Split up common into kernel,place,route

Signed-off-by: gatecat <gatecat@ds0.me>

59 files changed, 12002 insertions, 0 deletions

diff --git a/common/kernel/arch_api.h b/common/kernel/arch_api.h
new file mode 100644
index 00000000..14a30652
--- /dev/null
+++ b/common/kernel/arch_api.h
@@ -0,0 +1,158 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef ARCH_API_H
+#define ARCH_API_H
+
+#include <algorithm>
+
+#include "basectx.h"
+#include "idstring.h"
+#include "idstringlist.h"
+#include "nextpnr_assertions.h"
+#include "nextpnr_namespaces.h"
+#include "nextpnr_types.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+// The specification of the Arch API (pure virtual)
+template <typename R> struct ArchAPI : BaseCtx
+{
+    // Basic config
+    virtual IdString archId() const = 0;
+    virtual std::string getChipName() const = 0;
+    virtual typename R::ArchArgsT archArgs() const = 0;
+    virtual IdString archArgsToId(typename R::ArchArgsT args) const = 0;
+    virtual int getGridDimX() const = 0;
+    virtual int getGridDimY() const = 0;
+    virtual int getTileBelDimZ(int x, int y) const = 0;
+    virtual int getTilePipDimZ(int x, int y) const = 0;
+    virtual char getNameDelimiter() const = 0;
+    // Bel methods
+    virtual typename R::AllBelsRangeT getBels() const = 0;
+    virtual IdStringList getBelName(BelId bel) const = 0;
+    virtual BelId getBelByName(IdStringList name) const = 0;
+    virtual uint32_t getBelChecksum(BelId bel) const = 0;
+    virtual void bindBel(BelId bel, CellInfo *cell, PlaceStrength strength) = 0;
+    virtual void unbindBel(BelId bel) = 0;
+    virtual Loc getBelLocation(BelId bel) const = 0;
+    virtual BelId getBelByLocation(Loc loc) const = 0;
+    virtual typename R::TileBelsRangeT getBelsByTile(int x, int y) const = 0;
+    virtual bool getBelGlobalBuf(BelId bel) const = 0;
+    virtual bool checkBelAvail(BelId bel) const = 0;
+    virtual CellInfo *getBoundBelCell(BelId bel) const = 0;
+    virtual CellInfo *getConflictingBelCell(BelId bel) const = 0;
+    virtual IdString getBelType(BelId bel) const = 0;
+    virtual bool getBelHidden(BelId bel) const = 0;
+    virtual typename R::BelAttrsRangeT getBelAttrs(BelId bel) const = 0;
+    virtual WireId getBelPinWire(BelId bel, IdString pin) const = 0;
+    virtual PortType getBelPinType(BelId bel, IdString pin) const = 0;
+    virtual typename R::BelPinsRangeT getBelPins(BelId bel) const = 0;
+    virtual typename R::CellBelPinRangeT getBelPinsForCellPin(const CellInfo *cell_info, IdString pin) const = 0;
+    // Wire methods
+    virtual typename R::AllWiresRangeT getWires() const = 0;
+    virtual WireId getWireByName(IdStringList name) const = 0;
+    virtual IdStringList getWireName(WireId wire) const = 0;
+    virtual IdString getWireType(WireId wire) const = 0;
+    virtual typename R::WireAttrsRangeT getWireAttrs(WireId) const = 0;
+    virtual typename R::DownhillPipRangeT getPipsDownhill(WireId wire) const = 0;
+    virtual typename R::UphillPipRangeT getPipsUphill(WireId wire) const = 0;
+    virtual typename R::WireBelPinRangeT getWireBelPins(WireId wire) const = 0;
+    virtual uint32_t getWireChecksum(WireId wire) const = 0;
+    virtual void bindWire(WireId wire, NetInfo *net, PlaceStrength strength) = 0;
+    virtual void unbindWire(WireId wire) = 0;
+    virtual bool checkWireAvail(WireId wire) const = 0;
+    virtual NetInfo *getBoundWireNet(WireId wire) const = 0;
+    virtual WireId getConflictingWireWire(WireId wire) const = 0;
+    virtual NetInfo *getConflictingWireNet(WireId wire) const = 0;
+    virtual DelayQuad getWireDelay(WireId wire) const = 0;
+    // Pip methods
+    virtual typename R::AllPipsRangeT getPips() const = 0;
+    virtual PipId getPipByName(IdStringList name) const = 0;
+    virtual IdStringList getPipName(PipId pip) const = 0;
+    virtual IdString getPipType(PipId pip) const = 0;
+    virtual typename R::PipAttrsRangeT getPipAttrs(PipId) const = 0;
+    virtual uint32_t getPipChecksum(PipId pip) const = 0;
+    virtual void bindPip(PipId pip, NetInfo *net, PlaceStrength strength) = 0;
+    virtual void unbindPip(PipId pip) = 0;
+    virtual bool checkPipAvail(PipId pip) const = 0;
+    virtual bool checkPipAvailForNet(PipId pip, NetInfo *net) const = 0;
+    virtual NetInfo *getBoundPipNet(PipId pip) const = 0;
+    virtual WireId getConflictingPipWire(PipId pip) const = 0;
+    virtual NetInfo *getConflictingPipNet(PipId pip) const = 0;
+    virtual WireId getPipSrcWire(PipId pip) const = 0;
+    virtual WireId getPipDstWire(PipId pip) const = 0;
+    virtual DelayQuad getPipDelay(PipId pip) const = 0;
+    virtual Loc getPipLocation(PipId pip) const = 0;
+    // Group methods
+    virtual GroupId getGroupByName(IdStringList name) const = 0;
+    virtual IdStringList getGroupName(GroupId group) const = 0;
+    virtual typename R::AllGroupsRangeT getGroups() const = 0;
+    virtual typename R::GroupBelsRangeT getGroupBels(GroupId group) const = 0;
+    virtual typename R::GroupWiresRangeT getGroupWires(GroupId group) const = 0;
+    virtual typename R::GroupPipsRangeT getGroupPips(GroupId group) const = 0;
+    virtual typename R::GroupGroupsRangeT getGroupGroups(GroupId group) const = 0;
+    // Delay Methods
+    virtual delay_t predictDelay(BelId src_bel, IdString src_pin, BelId dst_bel, IdString dst_pin) const = 0;
+    virtual delay_t getDelayEpsilon() const = 0;
+    virtual delay_t getRipupDelayPenalty() const = 0;
+    virtual float getDelayNS(delay_t v) const = 0;
+    virtual delay_t getDelayFromNS(float ns) const = 0;
+    virtual uint32_t getDelayChecksum(delay_t v) const = 0;
+    virtual bool getBudgetOverride(const NetInfo *net_info, const PortRef &sink, delay_t &budget) const = 0;
+    virtual delay_t estimateDelay(WireId src, WireId dst) const = 0;
+    virtual ArcBounds getRouteBoundingBox(WireId src, WireId dst) const = 0;
+    // Decal methods
+    virtual typename R::DecalGfxRangeT getDecalGraphics(DecalId decal) const = 0;
+    virtual DecalXY getBelDecal(BelId bel) const = 0;
+    virtual DecalXY getWireDecal(WireId wire) const = 0;
+    virtual DecalXY getPipDecal(PipId pip) const = 0;
+    virtual DecalXY getGroupDecal(GroupId group) const = 0;
+    // Cell timing methods
+    virtual bool getCellDelay(const CellInfo *cell, IdString fromPort, IdString toPort, DelayQuad &delay) const = 0;
+    virtual TimingPortClass getPortTimingClass(const CellInfo *cell, IdString port, int &clockInfoCount) const = 0;
+    virtual TimingClockingInfo getPortClockingInfo(const CellInfo *cell, IdString port, int index) const = 0;
+    // Placement validity checks
+    virtual bool isValidBelForCellType(IdString cell_type, BelId bel) const = 0;
+    virtual IdString getBelBucketName(BelBucketId bucket) const = 0;
+    virtual BelBucketId getBelBucketByName(IdString name) const = 0;
+    virtual BelBucketId getBelBucketForBel(BelId bel) const = 0;
+    virtual BelBucketId getBelBucketForCellType(IdString cell_type) const = 0;
+    virtual bool isBelLocationValid(BelId bel) const = 0;
+    virtual typename R::CellTypeRangeT getCellTypes() const = 0;
+    virtual typename R::BelBucketRangeT getBelBuckets() const = 0;
+    virtual typename R::BucketBelRangeT getBelsInBucket(BelBucketId bucket) const = 0;
+    // Cluster methods
+    virtual CellInfo *getClusterRootCell(ClusterId cluster) const = 0;
+    virtual ArcBounds getClusterBounds(ClusterId cluster) const = 0;
+    virtual Loc getClusterOffset(const CellInfo *cell) const = 0;
+    virtual bool isClusterStrict(const CellInfo *cell) const = 0;
+    virtual bool getClusterPlacement(ClusterId cluster, BelId root_bel,
+                                     std::vector<std::pair<CellInfo *, BelId>> &placement) const = 0;
+    // Flow methods
+    virtual bool pack() = 0;
+    virtual bool place() = 0;
+    virtual bool route() = 0;
+    virtual void assignArchInfo() = 0;
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* ARCH_API_H */
diff --git a/common/kernel/arch_pybindings_shared.h b/common/kernel/arch_pybindings_shared.h
new file mode 100644
index 00000000..b3dc0506
--- /dev/null
+++ b/common/kernel/arch_pybindings_shared.h
@@ -0,0 +1,147 @@
+// Common Python bindings #included by all arches
+
+readonly_wrapper<Context, decltype(&Context::cells), &Context::cells, wrap_context<CellMap &>>::def_wrap(ctx_cls,
+                                                                                                         "cells");
+readonly_wrapper<Context, decltype(&Context::nets), &Context::nets, wrap_context<NetMap &>>::def_wrap(ctx_cls, "nets");
+readonly_wrapper<Context, decltype(&Context::net_aliases), &Context::net_aliases, wrap_context<AliasMap &>>::def_wrap(
+        ctx_cls, "net_aliases");
+readonly_wrapper<Context, decltype(&Context::hierarchy), &Context::hierarchy, wrap_context<HierarchyMap &>>::def_wrap(
+        ctx_cls, "hierarchy");
+readwrite_wrapper<Context, decltype(&Context::top_module), &Context::top_module, conv_to_str<IdString>,
+                  conv_from_str<IdString>>::def_wrap(ctx_cls, "top_module");
+readonly_wrapper<Context, decltype(&Context::timing_result), &Context::timing_result,
+                 wrap_context<TimingResult &>>::def_wrap(ctx_cls, "timing_result");
+
+fn_wrapper_0a<Context, decltype(&Context::getNameDelimiter), &Context::getNameDelimiter, pass_through<char>>::def_wrap(
+        ctx_cls, "getNameDelimiter");
+
+fn_wrapper_1a<Context, decltype(&Context::getNetByAlias), &Context::getNetByAlias, deref_and_wrap<NetInfo>,
+              conv_from_str<IdString>>::def_wrap(ctx_cls, "getNetByAlias");
+fn_wrapper_2a_v<Context, decltype(&Context::addClock), &Context::addClock, conv_from_str<IdString>,
+                pass_through<float>>::def_wrap(ctx_cls, "addClock");
+fn_wrapper_5a_v<Context, decltype(&Context::createRectangularRegion), &Context::createRectangularRegion,
+                conv_from_str<IdString>, pass_through<int>, pass_through<int>, pass_through<int>,
+                pass_through<int>>::def_wrap(ctx_cls, "createRectangularRegion");
+fn_wrapper_2a_v<Context, decltype(&Context::addBelToRegion), &Context::addBelToRegion, conv_from_str<IdString>,
+                conv_from_str<BelId>>::def_wrap(ctx_cls, "addBelToRegion");
+fn_wrapper_2a_v<Context, decltype(&Context::constrainCellToRegion), &Context::constrainCellToRegion,
+                conv_from_str<IdString>, conv_from_str<IdString>>::def_wrap(ctx_cls, "constrainCellToRegion");
+
+fn_wrapper_2a<Context, decltype(&Context::getNetinfoRouteDelay), &Context::getNetinfoRouteDelay, pass_through<delay_t>,
+              addr_and_unwrap<NetInfo>, unwrap_context<PortRef &>>::def_wrap(ctx_cls, "getNetinfoRouteDelay");
+
+fn_wrapper_1a<Context, decltype(&Context::createNet), &Context::createNet, deref_and_wrap<NetInfo>,
+              conv_from_str<IdString>>::def_wrap(ctx_cls, "createNet");
+fn_wrapper_3a_v<Context, decltype(&Context::connectPort), &Context::connectPort, conv_from_str<IdString>,
+                conv_from_str<IdString>, conv_from_str<IdString>>::def_wrap(ctx_cls, "connectPort");
+fn_wrapper_2a_v<Context, decltype(&Context::disconnectPort), &Context::disconnectPort, conv_from_str<IdString>,
+                conv_from_str<IdString>>::def_wrap(ctx_cls, "disconnectPort");
+fn_wrapper_1a_v<Context, decltype(&Context::ripupNet), &Context::ripupNet, conv_from_str<IdString>>::def_wrap(
+        ctx_cls, "ripupNet");
+fn_wrapper_1a_v<Context, decltype(&Context::lockNetRouting), &Context::lockNetRouting,
+                conv_from_str<IdString>>::def_wrap(ctx_cls, "lockNetRouting");
+
+fn_wrapper_2a<Context, decltype(&Context::createCell), &Context::createCell, deref_and_wrap<CellInfo>,
+              conv_from_str<IdString>, conv_from_str<IdString>>::def_wrap(ctx_cls, "createCell");
+fn_wrapper_2a_v<Context, decltype(&Context::copyBelPorts), &Context::copyBelPorts, conv_from_str<IdString>,
+                conv_from_str<BelId>>::def_wrap(ctx_cls, "copyBelPorts");
+
+fn_wrapper_1a<Context, decltype(&Context::getBelType), &Context::getBelType, conv_to_str<IdString>,
+              conv_from_str<BelId>>::def_wrap(ctx_cls, "getBelType");
+fn_wrapper_1a<Context, decltype(&Context::getBelLocation), &Context::getBelLocation, pass_through<Loc>,
+              conv_from_str<BelId>>::def_wrap(ctx_cls, "getBelLocation");
+fn_wrapper_1a<Context, decltype(&Context::checkBelAvail), &Context::checkBelAvail, pass_through<bool>,
+              conv_from_str<BelId>>::def_wrap(ctx_cls, "checkBelAvail");
+fn_wrapper_1a<Context, decltype(&Context::getBelChecksum), &Context::getBelChecksum, pass_through<uint32_t>,
+              conv_from_str<BelId>>::def_wrap(ctx_cls, "getBelChecksum");
+fn_wrapper_3a_v<Context, decltype(&Context::bindBel), &Context::bindBel, conv_from_str<BelId>,
+                addr_and_unwrap<CellInfo>, pass_through<PlaceStrength>>::def_wrap(ctx_cls, "bindBel");
+fn_wrapper_1a_v<Context, decltype(&Context::unbindBel), &Context::unbindBel, conv_from_str<BelId>>::def_wrap(
+        ctx_cls, "unbindBel");
+fn_wrapper_1a<Context, decltype(&Context::getBoundBelCell), &Context::getBoundBelCell, deref_and_wrap<CellInfo>,
+              conv_from_str<BelId>>::def_wrap(ctx_cls, "getBoundBelCell");
+fn_wrapper_1a<Context, decltype(&Context::getConflictingBelCell), &Context::getConflictingBelCell,
+              deref_and_wrap<CellInfo>, conv_from_str<BelId>>::def_wrap(ctx_cls, "getConflictingBelCell");
+fn_wrapper_0a<Context, decltype(&Context::getBels), &Context::getBels, wrap_context<BelRange>>::def_wrap(ctx_cls,
+                                                                                                         "getBels");
+
+fn_wrapper_2a<Context, decltype(&Context::getBelPinWire), &Context::getBelPinWire, conv_to_str<WireId>,
+              conv_from_str<BelId>, conv_from_str<IdString>>::def_wrap(ctx_cls, "getBelPinWire");
+fn_wrapper_2a<Context, decltype(&Context::getBelPinType), &Context::getBelPinType, pass_through<PortType>,
+              conv_from_str<BelId>, conv_from_str<IdString>>::def_wrap(ctx_cls, "getBelPinType");
+fn_wrapper_1a<Context, decltype(&Context::getWireBelPins), &Context::getWireBelPins, wrap_context<BelPinRange>,
+              conv_from_str<WireId>>::def_wrap(ctx_cls, "getWireBelPins");
+
+fn_wrapper_1a<Context, decltype(&Context::getWireChecksum), &Context::getWireChecksum, pass_through<uint32_t>,
+              conv_from_str<WireId>>::def_wrap(ctx_cls, "getWireChecksum");
+fn_wrapper_1a<Context, decltype(&Context::getWireType), &Context::getWireType, conv_to_str<IdString>,
+              conv_from_str<WireId>>::def_wrap(ctx_cls, "getWireType");
+fn_wrapper_3a_v<Context, decltype(&Context::bindWire), &Context::bindWire, conv_from_str<WireId>,
+                addr_and_unwrap<NetInfo>, pass_through<PlaceStrength>>::def_wrap(ctx_cls, "bindWire");
+fn_wrapper_1a_v<Context, decltype(&Context::unbindWire), &Context::unbindWire, conv_from_str<WireId>>::def_wrap(
+        ctx_cls, "unbindWire");
+fn_wrapper_1a<Context, decltype(&Context::checkWireAvail), &Context::checkWireAvail, pass_through<bool>,
+              conv_from_str<WireId>>::def_wrap(ctx_cls, "checkWireAvail");
+fn_wrapper_1a<Context, decltype(&Context::getBoundWireNet), &Context::getBoundWireNet, deref_and_wrap<NetInfo>,
+              conv_from_str<WireId>>::def_wrap(ctx_cls, "getBoundWireNet");
+fn_wrapper_1a<Context, decltype(&Context::getConflictingWireNet), &Context::getConflictingWireNet,
+              deref_and_wrap<NetInfo>, conv_from_str<WireId>>::def_wrap(ctx_cls, "getConflictingWireNet");
+
+fn_wrapper_0a<Context, decltype(&Context::getWires), &Context::getWires, wrap_context<WireRange>>::def_wrap(ctx_cls,
+                                                                                                            "getWires");
+
+fn_wrapper_0a<Context, decltype(&Context::getPips), &Context::getPips, wrap_context<AllPipRange>>::def_wrap(ctx_cls,
+                                                                                                            "getPips");
+fn_wrapper_1a<Context, decltype(&Context::getPipChecksum), &Context::getPipChecksum, pass_through<uint32_t>,
+              conv_from_str<PipId>>::def_wrap(ctx_cls, "getPipChecksum");
+fn_wrapper_1a<Context, decltype(&Context::getPipLocation), &Context::getPipLocation, pass_through<Loc>,
+              conv_from_str<PipId>>::def_wrap(ctx_cls, "getPipLocation");
+fn_wrapper_3a_v<Context, decltype(&Context::bindPip), &Context::bindPip, conv_from_str<PipId>, addr_and_unwrap<NetInfo>,
+                pass_through<PlaceStrength>>::def_wrap(ctx_cls, "bindPip");
+fn_wrapper_1a_v<Context, decltype(&Context::unbindPip), &Context::unbindPip, conv_from_str<PipId>>::def_wrap(
+        ctx_cls, "unbindPip");
+fn_wrapper_1a<Context, decltype(&Context::checkPipAvail), &Context::checkPipAvail, pass_through<bool>,
+              conv_from_str<PipId>>::def_wrap(ctx_cls, "checkPipAvail");
+fn_wrapper_1a<Context, decltype(&Context::getBoundPipNet), &Context::getBoundPipNet, deref_and_wrap<NetInfo>,
+              conv_from_str<PipId>>::def_wrap(ctx_cls, "getBoundPipNet");
+fn_wrapper_1a<Context, decltype(&Context::getConflictingPipNet), &Context::getConflictingPipNet,
+              deref_and_wrap<NetInfo>, conv_from_str<PipId>>::def_wrap(ctx_cls, "getConflictingPipNet");
+
+fn_wrapper_1a<Context, decltype(&Context::getPipsDownhill), &Context::getPipsDownhill, wrap_context<DownhillPipRange>,
+              conv_from_str<WireId>>::def_wrap(ctx_cls, "getPipsDownhill");
+fn_wrapper_1a<Context, decltype(&Context::getPipsUphill), &Context::getPipsUphill, wrap_context<UphillPipRange>,
+              conv_from_str<WireId>>::def_wrap(ctx_cls, "getPipsUphill");
+
+fn_wrapper_1a<Context, decltype(&Context::getPipSrcWire), &Context::getPipSrcWire, conv_to_str<WireId>,
+              conv_from_str<PipId>>::def_wrap(ctx_cls, "getPipSrcWire");
+fn_wrapper_1a<Context, decltype(&Context::getPipDstWire), &Context::getPipDstWire, conv_to_str<WireId>,
+              conv_from_str<PipId>>::def_wrap(ctx_cls, "getPipDstWire");
+fn_wrapper_1a<Context, decltype(&Context::getPipDelay), &Context::getPipDelay, pass_through<DelayQuad>,
+              conv_from_str<PipId>>::def_wrap(ctx_cls, "getPipDelay");
+
+fn_wrapper_0a<Context, decltype(&Context::getChipName), &Context::getChipName, pass_through<std::string>>::def_wrap(
+        ctx_cls, "getChipName");
+fn_wrapper_0a<Context, decltype(&Context::archId), &Context::archId, conv_to_str<IdString>>::def_wrap(ctx_cls,
+                                                                                                      "archId");
+
+fn_wrapper_2a_v<Context, decltype(&Context::writeSVG), &Context::writeSVG, pass_through<std::string>,
+                pass_through<std::string>>::def_wrap(ctx_cls, "writeSVG");
+
+fn_wrapper_1a<Context, decltype(&Context::isBelLocationValid), &Context::isBelLocationValid, pass_through<bool>,
+              conv_from_str<BelId>>::def_wrap(ctx_cls, "isBelLocationValid");
+
+// const\_range\<BelBucketId\> getBelBuckets() const
+fn_wrapper_0a<Context, decltype(&Context::getBelBuckets), &Context::getBelBuckets,
+              wrap_context<BelBucketRange>>::def_wrap(ctx_cls, "getBelBuckets");
+// BelBucketId getBelBucketForBel(BelId bel) const
+fn_wrapper_1a<Context, decltype(&Context::getBelBucketForBel), &Context::getBelBucketForBel, conv_to_str<BelBucketId>,
+              conv_from_str<BelId>>::def_wrap(ctx_cls, "getBelBucketForBel");
+// BelBucketId getBelBucketForCellType(IdString cell\_type) const
+fn_wrapper_1a<Context, decltype(&Context::getBelBucketForCellType), &Context::getBelBucketForCellType,
+              conv_to_str<BelBucketId>, conv_from_str<IdString>>::def_wrap(ctx_cls, "getBelBucketForCellType");
+// const\_range\<BelId\> getBelsInBucket(BelBucketId bucket) const
+fn_wrapper_1a<Context, decltype(&Context::getBelsInBucket), &Context::getBelsInBucket,
+              wrap_context<BelRangeForBelBucket>, conv_from_str<BelBucketId>>::def_wrap(ctx_cls, "getBelsInBucket");
+// bool isValidBelForCellType(IdString cell\_type, BelId bel) const
+fn_wrapper_2a<Context, decltype(&Context::isValidBelForCellType), &Context::isValidBelForCellType, pass_through<bool>,
+              conv_from_str<IdString>, conv_from_str<BelId>>::def_wrap(ctx_cls, "isValidBelForCellType");
diff --git a/common/kernel/archcheck.cc b/common/kernel/archcheck.cc
new file mode 100644
index 00000000..23ec7aee
--- /dev/null
+++ b/common/kernel/archcheck.cc
@@ -0,0 +1,408 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "log.h"
+#include "nextpnr.h"
+
+#if 0
+#define dbg(...) log(__VA_ARGS__)
+#else
+#define dbg(...)
+#endif
+
+USING_NEXTPNR_NAMESPACE
+
+#ifndef ARCH_MISTRAL
+// The LRU cache to reduce memory usage during the connectivity check relies on getPips() having some spacial locality,
+// which the current CycloneV arch impl doesn't have. This may be fixed in the future, though.
+#define USING_LRU_CACHE
+#endif
+
+namespace {
+
+void archcheck_names(const Context *ctx)
+{
+    log_info("Checking entity names.\n");
+
+    log_info("Checking bel names..\n");
+    for (BelId bel : ctx->getBels()) {
+        IdStringList name = ctx->getBelName(bel);
+        BelId bel2 = ctx->getBelByName(name);
+        if (bel != bel2) {
+            log_error("bel != bel2, name = %s\n", ctx->nameOfBel(bel));
+        }
+    }
+
+    log_info("Checking wire names..\n");
+    for (WireId wire : ctx->getWires()) {
+        IdStringList name = ctx->getWireName(wire);
+        WireId wire2 = ctx->getWireByName(name);
+        if (wire != wire2) {
+            log_error("wire != wire2, name = %s\n", ctx->nameOfWire(wire));
+        }
+    }
+
+    log_info("Checking bucket names..\n");
+    for (BelBucketId bucket : ctx->getBelBuckets()) {
+        IdString name = ctx->getBelBucketName(bucket);
+        BelBucketId bucket2 = ctx->getBelBucketByName(name);
+        if (bucket != bucket2) {
+            log_error("bucket != bucket2, name = %s\n", name.c_str(ctx));
+        }
+    }
+
+#ifndef ARCH_ECP5
+    log_info("Checking pip names..\n");
+    for (PipId pip : ctx->getPips()) {
+        IdStringList name = ctx->getPipName(pip);
+        PipId pip2 = ctx->getPipByName(name);
+        if (pip != pip2) {
+            log_error("pip != pip2, name = %s\n", ctx->nameOfPip(pip));
+        }
+    }
+#endif
+    log_break();
+}
+
+void archcheck_locs(const Context *ctx)
+{
+    log_info("Checking location data.\n");
+
+    log_info("Checking all bels..\n");
+    for (BelId bel : ctx->getBels()) {
+        log_assert(bel != BelId());
+        dbg("> %s\n", ctx->getBelName(bel).c_str(ctx));
+
+        Loc loc = ctx->getBelLocation(bel);
+        dbg("   ... %d %d %d\n", loc.x, loc.y, loc.z);
+
+        log_assert(0 <= loc.x);
+        log_assert(0 <= loc.y);
+        log_assert(0 <= loc.z);
+        log_assert(loc.x < ctx->getGridDimX());
+        log_assert(loc.y < ctx->getGridDimY());
+        log_assert(loc.z < ctx->getTileBelDimZ(loc.x, loc.y));
+
+        BelId bel2 = ctx->getBelByLocation(loc);
+        dbg("   ... %s\n", ctx->getBelName(bel2).c_str(ctx));
+        log_assert(bel == bel2);
+    }
+
+    log_info("Checking all locations..\n");
+    for (int x = 0; x < ctx->getGridDimX(); x++)
+        for (int y = 0; y < ctx->getGridDimY(); y++) {
+            dbg("> %d %d\n", x, y);
+            pool<int> usedz;
+
+            for (int z = 0; z < ctx->getTileBelDimZ(x, y); z++) {
+                BelId bel = ctx->getBelByLocation(Loc(x, y, z));
+                if (bel == BelId())
+                    continue;
+                Loc loc = ctx->getBelLocation(bel);
+                dbg("   + %d %s\n", z, ctx->nameOfBel(bel));
+                log_assert(x == loc.x);
+                log_assert(y == loc.y);
+                log_assert(z == loc.z);
+                usedz.insert(z);
+            }
+
+            for (BelId bel : ctx->getBelsByTile(x, y)) {
+                Loc loc = ctx->getBelLocation(bel);
+                dbg("   - %d %s\n", loc.z, ctx->nameOfBel(bel));
+                log_assert(x == loc.x);
+                log_assert(y == loc.y);
+                log_assert(usedz.count(loc.z));
+                usedz.erase(loc.z);
+            }
+
+            log_assert(usedz.empty());
+        }
+
+    log_break();
+}
+
+// Implements a LRU cache for pip to wire via getPipsDownhill/getPipsUphill.
+//
+// This allows a fast way to check getPipsDownhill/getPipsUphill from getPips,
+// without balloning memory usage.
+struct LruWireCacheMap
+{
+    LruWireCacheMap(const Context *ctx, size_t cache_size) : ctx(ctx), cache_size(cache_size)
+    {
+        cache_hits = 0;
+        cache_misses = 0;
+        cache_evictions = 0;
+    }
+
+    const Context *ctx;
+    size_t cache_size;
+
+    // Cache stats for checking on cache behavior.
+    size_t cache_hits;
+    size_t cache_misses;
+    size_t cache_evictions;
+
+    // Most recent accessed wires are added to the back of the list, front of
+    // list is oldest wire in cache.
+    std::list<WireId> last_access_list;
+    // Quick wire -> list element lookup.
+    dict<WireId, std::list<WireId>::iterator> last_access_map;
+
+    dict<PipId, WireId> pips_downhill;
+    dict<PipId, WireId> pips_uphill;
+
+    void removeWireFromCache(WireId wire_to_remove)
+    {
+        for (PipId pip : ctx->getPipsDownhill(wire_to_remove)) {
+            log_assert(pips_downhill.erase(pip) == 1);
+        }
+
+        for (PipId pip : ctx->getPipsUphill(wire_to_remove)) {
+            log_assert(pips_uphill.erase(pip) == 1);
+        }
+    }
+
+    void addWireToCache(WireId wire)
+    {
+        for (PipId pip : ctx->getPipsDownhill(wire)) {
+            auto result = pips_downhill.emplace(pip, wire);
+            log_assert(result.second);
+        }
+
+        for (PipId pip : ctx->getPipsUphill(wire)) {
+            auto result = pips_uphill.emplace(pip, wire);
+            log_assert(result.second);
+        }
+    }
+
+    void populateCache(WireId wire)
+    {
+        // Put this wire at the end of last_access_list.
+        auto iter = last_access_list.emplace(last_access_list.end(), wire);
+        last_access_map.emplace(wire, iter);
+
+        if (last_access_list.size() > cache_size) {
+            // Cache is full, remove front of last_access_list.
+            cache_evictions += 1;
+            WireId wire_to_remove = last_access_list.front();
+            last_access_list.pop_front();
+            log_assert(last_access_map.erase(wire_to_remove) == 1);
+
+            removeWireFromCache(wire_to_remove);
+        }
+
+        addWireToCache(wire);
+    }
+
+    // Determine if wire is in the cache.  If wire is not in the cache,
+    // adds the wire to the cache, and potentially evicts the oldest wire if
+    // cache is now full.
+    void checkCache(WireId wire)
+    {
+        auto iter = last_access_map.find(wire);
+        if (iter == last_access_map.end()) {
+            cache_misses += 1;
+            populateCache(wire);
+        } else {
+            // Record that this wire has been accessed.
+            cache_hits += 1;
+            last_access_list.splice(last_access_list.end(), last_access_list, iter->second);
+        }
+    }
+
+    // Returns true if pip is uphill of wire (e.g. pip in getPipsUphill(wire)).
+    bool isPipUphill(PipId pip, WireId wire)
+    {
+        checkCache(wire);
+        return pips_uphill.at(pip) == wire;
+    }
+
+    // Returns true if pip is downhill of wire (e.g. pip in getPipsDownhill(wire)).
+    bool isPipDownhill(PipId pip, WireId wire)
+    {
+        checkCache(wire);
+        return pips_downhill.at(pip) == wire;
+    }
+
+    void cache_info() const
+    {
+        log_info("Cache hits: %zu\n", cache_hits);
+        log_info("Cache misses: %zu\n", cache_misses);
+        log_info("Cache evictions: %zu\n", cache_evictions);
+    }
+};
+
+void archcheck_conn(const Context *ctx)
+{
+    log_info("Checking connectivity data.\n");
+
+    log_info("Checking all wires...\n");
+
+#ifndef USING_LRU_CACHE
+    dict<PipId, WireId> pips_downhill;
+    dict<PipId, WireId> pips_uphill;
+#endif
+
+    for (WireId wire : ctx->getWires()) {
+        for (BelPin belpin : ctx->getWireBelPins(wire)) {
+            WireId wire2 = ctx->getBelPinWire(belpin.bel, belpin.pin);
+            log_assert(wire == wire2);
+        }
+
+        for (PipId pip : ctx->getPipsDownhill(wire)) {
+            WireId wire2 = ctx->getPipSrcWire(pip);
+            log_assert(wire == wire2);
+#ifndef USING_LRU_CACHE
+            auto result = pips_downhill.emplace(pip, wire);
+            log_assert(result.second);
+#endif
+        }
+
+        for (PipId pip : ctx->getPipsUphill(wire)) {
+            WireId wire2 = ctx->getPipDstWire(pip);
+            log_assert(wire == wire2);
+#ifndef USING_LRU_CACHE
+            auto result = pips_uphill.emplace(pip, wire);
+            log_assert(result.second);
+#endif
+        }
+    }
+
+    log_info("Checking all BELs...\n");
+    for (BelId bel : ctx->getBels()) {
+        for (IdString pin : ctx->getBelPins(bel)) {
+            WireId wire = ctx->getBelPinWire(bel, pin);
+
+            if (wire == WireId()) {
+                continue;
+            }
+
+            bool found_belpin = false;
+            for (BelPin belpin : ctx->getWireBelPins(wire)) {
+                if (belpin.bel == bel && belpin.pin == pin) {
+                    found_belpin = true;
+                    break;
+                }
+            }
+
+            log_assert(found_belpin);
+        }
+    }
+#ifdef USING_LRU_CACHE
+    // This cache is used to meet two goals:
+    //  - Avoid linear scan by invoking getPipsDownhill/getPipsUphill directly.
+    //  - Avoid having pip -> wire maps for the entire part.
+    //
+    // The overhead of maintaining the cache is small relatively to the memory
+    // gains by avoiding the full pip -> wire map, and still preserves a fast
+    // pip -> wire, assuming that pips are returned from getPips with some
+    // chip locality.
+    LruWireCacheMap pip_cache(ctx, /*cache_size=*/64 * 1024);
+#endif
+    log_info("Checking all PIPs...\n");
+    for (PipId pip : ctx->getPips()) {
+        WireId src_wire = ctx->getPipSrcWire(pip);
+        if (src_wire != WireId()) {
+#ifdef USING_LRU_CACHE
+            log_assert(pip_cache.isPipDownhill(pip, src_wire));
+#else
+            log_assert(pips_downhill.at(pip) == src_wire);
+#endif
+        }
+
+        WireId dst_wire = ctx->getPipDstWire(pip);
+        if (dst_wire != WireId()) {
+#ifdef USING_LRU_CACHE
+            log_assert(pip_cache.isPipUphill(pip, dst_wire));
+#else
+            log_assert(pips_uphill.at(pip) == dst_wire);
+#endif
+        }
+    }
+}
+
+void archcheck_buckets(const Context *ctx)
+{
+    log_info("Checking bucket data.\n");
+
+    // BEL buckets should be subsets of BELs that form an exact cover.
+    // In particular that means cell types in a bucket should only be
+    // placable in that bucket.
+    for (BelBucketId bucket : ctx->getBelBuckets()) {
+
+        // Find out which cell types are in this bucket.
+        pool<IdString> cell_types_in_bucket;
+        for (IdString cell_type : ctx->getCellTypes()) {
+            if (ctx->getBelBucketForCellType(cell_type) == bucket) {
+                cell_types_in_bucket.insert(cell_type);
+            }
+        }
+
+        // Make sure that all cell types in this bucket have at least one
+        // BelId they can be placed at.
+        pool<IdString> cell_types_unused;
+
+        pool<BelId> bels_in_bucket;
+        for (BelId bel : ctx->getBelsInBucket(bucket)) {
+            BelBucketId bucket2 = ctx->getBelBucketForBel(bel);
+            log_assert(bucket == bucket2);
+
+            bels_in_bucket.insert(bel);
+
+            // Check to see if a cell type not in this bucket can be
+            // placed at a BEL in this bucket.
+            for (IdString cell_type : ctx->getCellTypes()) {
+                if (ctx->getBelBucketForCellType(cell_type) == bucket) {
+                    if (ctx->isValidBelForCellType(cell_type, bel)) {
+                        cell_types_unused.erase(cell_type);
+                    }
+                } else {
+                    log_assert(!ctx->isValidBelForCellType(cell_type, bel));
+                }
+            }
+        }
+
+        // Verify that any BEL not in this bucket reports a different
+        // bucket.
+        for (BelId bel : ctx->getBels()) {
+            if (ctx->getBelBucketForBel(bel) != bucket) {
+                log_assert(bels_in_bucket.count(bel) == 0);
+            }
+        }
+
+        log_assert(cell_types_unused.empty());
+    }
+}
+
+} // namespace
+
+NEXTPNR_NAMESPACE_BEGIN
+
+void Context::archcheck() const
+{
+    log_info("Running architecture database integrity check.\n");
+    log_break();
+
+    archcheck_names(this);
+    archcheck_locs(this);
+    archcheck_conn(this);
+    archcheck_buckets(this);
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/base_arch.h b/common/kernel/base_arch.h
new file mode 100644
index 00000000..3055619d
--- /dev/null
+++ b/common/kernel/base_arch.h
@@ -0,0 +1,486 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef BASE_ARCH_H
+#define BASE_ARCH_H
+
+#include <array>
+#include <vector>
+
+#include "arch_api.h"
+#include "base_clusterinfo.h"
+#include "idstring.h"
+#include "nextpnr_types.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+namespace {
+// For several functions; such as bel/wire/pip attributes; the trivial implementation is to return an empty vector
+// But an arch might want to do something fancy with a custom range type that doesn't provide a constructor
+// So some cursed C++ is needed to return an empty object if possible; or error out if not; is needed
+template <typename Tc> typename std::enable_if<std::is_constructible<Tc>::value, Tc>::type empty_if_possible()
+{
+    return Tc();
+}
+template <typename Tc> typename std::enable_if<!std::is_constructible<Tc>::value, Tc>::type empty_if_possible()
+{
+    NPNR_ASSERT_FALSE("attempting to use default implementation of range-returning function with range type lacking "
+                      "default constructor!");
+}
+
+// Provide a default implementation of bel bucket name if typedef'd to IdString
+template <typename Tbbid>
+typename std::enable_if<std::is_same<Tbbid, IdString>::value, IdString>::type bbid_to_name(Tbbid id)
+{
+    return id;
+}
+template <typename Tbbid>
+typename std::enable_if<!std::is_same<Tbbid, IdString>::value, IdString>::type bbid_to_name(Tbbid id)
+{
+    NPNR_ASSERT_FALSE("getBelBucketName must be implemented when BelBucketId is a type other than IdString!");
+}
+template <typename Tbbid>
+typename std::enable_if<std::is_same<Tbbid, IdString>::value, BelBucketId>::type bbid_from_name(IdString name)
+{
+    return name;
+}
+template <typename Tbbid>
+typename std::enable_if<!std::is_same<Tbbid, IdString>::value, BelBucketId>::type bbid_from_name(IdString name)
+{
+    NPNR_ASSERT_FALSE("getBelBucketByName must be implemented when BelBucketId is a type other than IdString!");
+}
+
+// For the cell type and bel type ranges; we want to return our stored vectors only if the type matches
+template <typename Tret, typename Tc>
+typename std::enable_if<std::is_same<Tret, Tc>::value, Tret>::type return_if_match(Tret r)
+{
+    return r;
+}
+
+template <typename Tret, typename Tc>
+typename std::enable_if<!std::is_same<Tret, Tc>::value, Tc>::type return_if_match(Tret r)
+{
+    NPNR_ASSERT_FALSE("default implementations of cell type and bel bucket range functions only available when the "
+                      "respective range types are 'const std::vector&'");
+}
+
+// Default implementations of the clustering functions
+template <typename Tid>
+typename std::enable_if<std::is_same<Tid, IdString>::value, CellInfo *>::type get_cluster_root(const BaseCtx *ctx,
+                                                                                               Tid cluster)
+{
+    return ctx->cells.at(cluster).get();
+}
+
+template <typename Tid>
+typename std::enable_if<!std::is_same<Tid, IdString>::value, CellInfo *>::type get_cluster_root(const BaseCtx *ctx,
+                                                                                                Tid cluster)
+{
+    NPNR_ASSERT_FALSE("default implementation of getClusterRootCell requires ClusterId to be IdString");
+}
+
+// Executes the lambda with the base cluster data, only if the derivation works
+template <typename Tret, typename Tcell, typename Tfunc>
+typename std::enable_if<std::is_base_of<BaseClusterInfo, Tcell>::value, Tret>::type
+if_using_basecluster(const Tcell *cell, Tfunc func)
+{
+    return func(static_cast<const BaseClusterInfo *>(cell));
+}
+template <typename Tret, typename Tcell, typename Tfunc>
+typename std::enable_if<!std::is_base_of<BaseClusterInfo, Tcell>::value, Tret>::type
+if_using_basecluster(const Tcell *cell, Tfunc func)
+{
+    NPNR_ASSERT_FALSE(
+            "default implementation of cluster functions requires ArchCellInfo to derive from BaseClusterInfo");
+}
+
+} // namespace
+
+// This contains the relevant range types for the default implementations of Arch functions
+struct BaseArchRanges
+{
+    // Bels
+    using CellBelPinRangeT = std::array<IdString, 1>;
+    // Attributes
+    using BelAttrsRangeT = std::vector<std::pair<IdString, std::string>>;
+    using WireAttrsRangeT = std::vector<std::pair<IdString, std::string>>;
+    using PipAttrsRangeT = std::vector<std::pair<IdString, std::string>>;
+    // Groups
+    using AllGroupsRangeT = std::vector<GroupId>;
+    using GroupBelsRangeT = std::vector<BelId>;
+    using GroupWiresRangeT = std::vector<WireId>;
+    using GroupPipsRangeT = std::vector<PipId>;
+    using GroupGroupsRangeT = std::vector<GroupId>;
+    // Decals
+    using DecalGfxRangeT = std::vector<GraphicElement>;
+    // Placement validity
+    using CellTypeRangeT = const std::vector<IdString> &;
+    using BelBucketRangeT = const std::vector<BelBucketId> &;
+    using BucketBelRangeT = const std::vector<BelId> &;
+};
+
+template <typename R> struct BaseArch : ArchAPI<R>
+{
+    // --------------------------------------------------------------
+    // Default, trivial, implementations of Arch API functions for arches that don't need complex behaviours
+
+    // Basic config
+    virtual IdString archId() const override { return this->id(NPNR_STRINGIFY(ARCHNAME)); }
+    virtual IdString archArgsToId(typename R::ArchArgsT args) const override { return IdString(); }
+    virtual int getTilePipDimZ(int x, int y) const override { return 1; }
+    virtual char getNameDelimiter() const override { return ' '; }
+
+    // Bel methods
+    virtual uint32_t getBelChecksum(BelId bel) const override { return bel.hash(); }
+    virtual void bindBel(BelId bel, CellInfo *cell, PlaceStrength strength) override
+    {
+        NPNR_ASSERT(bel != BelId());
+        auto &entry = base_bel2cell[bel];
+        NPNR_ASSERT(entry == nullptr);
+        cell->bel = bel;
+        cell->belStrength = strength;
+        entry = cell;
+        this->refreshUiBel(bel);
+    }
+    virtual void unbindBel(BelId bel) override
+    {
+        NPNR_ASSERT(bel != BelId());
+        auto &entry = base_bel2cell[bel];
+        NPNR_ASSERT(entry != nullptr);
+        entry->bel = BelId();
+        entry->belStrength = STRENGTH_NONE;
+        entry = nullptr;
+        this->refreshUiBel(bel);
+    }
+
+    virtual bool getBelHidden(BelId bel) const override { return false; }
+
+    virtual bool getBelGlobalBuf(BelId bel) const override { return false; }
+    virtual bool checkBelAvail(BelId bel) const override { return getBoundBelCell(bel) == nullptr; };
+    virtual CellInfo *getBoundBelCell(BelId bel) const override
+    {
+        auto fnd = base_bel2cell.find(bel);
+        return fnd == base_bel2cell.end() ? nullptr : fnd->second;
+    }
+    virtual CellInfo *getConflictingBelCell(BelId bel) const override { return getBoundBelCell(bel); }
+    virtual typename R::BelAttrsRangeT getBelAttrs(BelId bel) const override
+    {
+        return empty_if_possible<typename R::BelAttrsRangeT>();
+    }
+
+    virtual typename R::CellBelPinRangeT getBelPinsForCellPin(const CellInfo *cell_info, IdString pin) const override
+    {
+        return return_if_match<std::array<IdString, 1>, typename R::CellBelPinRangeT>({pin});
+    }
+
+    // Wire methods
+    virtual IdString getWireType(WireId wire) const override { return IdString(); }
+    virtual typename R::WireAttrsRangeT getWireAttrs(WireId) const override
+    {
+        return empty_if_possible<typename R::WireAttrsRangeT>();
+    }
+    virtual uint32_t getWireChecksum(WireId wire) const override { return wire.hash(); }
+
+    virtual void bindWire(WireId wire, NetInfo *net, PlaceStrength strength) override
+    {
+        NPNR_ASSERT(wire != WireId());
+        auto &w2n_entry = base_wire2net[wire];
+        NPNR_ASSERT(w2n_entry == nullptr);
+        net->wires[wire].pip = PipId();
+        net->wires[wire].strength = strength;
+        w2n_entry = net;
+        this->refreshUiWire(wire);
+    }
+    virtual void unbindWire(WireId wire) override
+    {
+        NPNR_ASSERT(wire != WireId());
+        auto &w2n_entry = base_wire2net[wire];
+        NPNR_ASSERT(w2n_entry != nullptr);
+
+        auto &net_wires = w2n_entry->wires;
+        auto it = net_wires.find(wire);
+        NPNR_ASSERT(it != net_wires.end());
+
+        auto pip = it->second.pip;
+        if (pip != PipId()) {
+            base_pip2net[pip] = nullptr;
+        }
+
+        net_wires.erase(it);
+        base_wire2net[wire] = nullptr;
+
+        w2n_entry = nullptr;
+        this->refreshUiWire(wire);
+    }
+    virtual bool checkWireAvail(WireId wire) const override { return getBoundWireNet(wire) == nullptr; }
+    virtual NetInfo *getBoundWireNet(WireId wire) const override
+    {
+        auto fnd = base_wire2net.find(wire);
+        return fnd == base_wire2net.end() ? nullptr : fnd->second;
+    }
+    virtual WireId getConflictingWireWire(WireId wire) const override { return wire; };
+    virtual NetInfo *getConflictingWireNet(WireId wire) const override { return getBoundWireNet(wire); }
+
+    // Pip methods
+    virtual IdString getPipType(PipId pip) const override { return IdString(); }
+    virtual typename R::PipAttrsRangeT getPipAttrs(PipId) const override
+    {
+        return empty_if_possible<typename R::PipAttrsRangeT>();
+    }
+    virtual uint32_t getPipChecksum(PipId pip) const override { return pip.hash(); }
+    virtual void bindPip(PipId pip, NetInfo *net, PlaceStrength strength) override
+    {
+        NPNR_ASSERT(pip != PipId());
+        auto &p2n_entry = base_pip2net[pip];
+        NPNR_ASSERT(p2n_entry == nullptr);
+        p2n_entry = net;
+
+        WireId dst = this->getPipDstWire(pip);
+        auto &w2n_entry = base_wire2net[dst];
+        NPNR_ASSERT(w2n_entry == nullptr);
+        w2n_entry = net;
+        net->wires[dst].pip = pip;
+        net->wires[dst].strength = strength;
+    }
+    virtual void unbindPip(PipId pip) override
+    {
+        NPNR_ASSERT(pip != PipId());
+        auto &p2n_entry = base_pip2net[pip];
+        NPNR_ASSERT(p2n_entry != nullptr);
+        WireId dst = this->getPipDstWire(pip);
+
+        auto &w2n_entry = base_wire2net[dst];
+        NPNR_ASSERT(w2n_entry != nullptr);
+        w2n_entry = nullptr;
+
+        p2n_entry->wires.erase(dst);
+        p2n_entry = nullptr;
+    }
+    virtual bool checkPipAvail(PipId pip) const override { return getBoundPipNet(pip) == nullptr; }
+    virtual bool checkPipAvailForNet(PipId pip, NetInfo *net) const override
+    {
+        NetInfo *bound_net = getBoundPipNet(pip);
+        return bound_net == nullptr || bound_net == net;
+    }
+    virtual NetInfo *getBoundPipNet(PipId pip) const override
+    {
+        auto fnd = base_pip2net.find(pip);
+        return fnd == base_pip2net.end() ? nullptr : fnd->second;
+    }
+    virtual WireId getConflictingPipWire(PipId pip) const override { return WireId(); }
+    virtual NetInfo *getConflictingPipNet(PipId pip) const override { return getBoundPipNet(pip); }
+
+    // Group methods
+    virtual GroupId getGroupByName(IdStringList name) const override { return GroupId(); };
+    virtual IdStringList getGroupName(GroupId group) const override { return IdStringList(); };
+    virtual typename R::AllGroupsRangeT getGroups() const override
+    {
+        return empty_if_possible<typename R::AllGroupsRangeT>();
+    }
+    // Default implementation of these assumes no groups so never called
+    virtual typename R::GroupBelsRangeT getGroupBels(GroupId group) const override
+    {
+        NPNR_ASSERT_FALSE("unreachable");
+    };
+    virtual typename R::GroupWiresRangeT getGroupWires(GroupId group) const override
+    {
+        NPNR_ASSERT_FALSE("unreachable");
+    };
+    virtual typename R::GroupPipsRangeT getGroupPips(GroupId group) const override
+    {
+        NPNR_ASSERT_FALSE("unreachable");
+    };
+    virtual typename R::GroupGroupsRangeT getGroupGroups(GroupId group) const override
+    {
+        NPNR_ASSERT_FALSE("unreachable");
+    };
+
+    // Delay methods
+    virtual bool getBudgetOverride(const NetInfo *net_info, const PortRef &sink, delay_t &budget) const override
+    {
+        return false;
+    }
+
+    // Decal methods
+    virtual typename R::DecalGfxRangeT getDecalGraphics(DecalId decal) const override
+    {
+        return empty_if_possible<typename R::DecalGfxRangeT>();
+    };
+    virtual DecalXY getBelDecal(BelId bel) const override { return DecalXY(); }
+    virtual DecalXY getWireDecal(WireId wire) const override { return DecalXY(); }
+    virtual DecalXY getPipDecal(PipId pip) const override { return DecalXY(); }
+    virtual DecalXY getGroupDecal(GroupId group) const override { return DecalXY(); }
+
+    // Cell timing methods
+    virtual bool getCellDelay(const CellInfo *cell, IdString fromPort, IdString toPort, DelayQuad &delay) const override
+    {
+        return false;
+    }
+    virtual TimingPortClass getPortTimingClass(const CellInfo *cell, IdString port, int &clockInfoCount) const override
+    {
+        return TMG_IGNORE;
+    }
+    virtual TimingClockingInfo getPortClockingInfo(const CellInfo *cell, IdString port, int index) const override
+    {
+        NPNR_ASSERT_FALSE("unreachable");
+    }
+
+    // Placement validity checks
+    virtual bool isValidBelForCellType(IdString cell_type, BelId bel) const override
+    {
+        return cell_type == this->getBelType(bel);
+    }
+    virtual IdString getBelBucketName(BelBucketId bucket) const override { return bbid_to_name<BelBucketId>(bucket); }
+    virtual BelBucketId getBelBucketByName(IdString name) const override { return bbid_from_name<BelBucketId>(name); }
+    virtual BelBucketId getBelBucketForBel(BelId bel) const override
+    {
+        return getBelBucketForCellType(this->getBelType(bel));
+    };
+    virtual BelBucketId getBelBucketForCellType(IdString cell_type) const override
+    {
+        return getBelBucketByName(cell_type);
+    };
+    virtual bool isBelLocationValid(BelId bel) const override { return true; }
+    virtual typename R::CellTypeRangeT getCellTypes() const override
+    {
+        NPNR_ASSERT(cell_types_initialised);
+        return return_if_match<const std::vector<IdString> &, typename R::CellTypeRangeT>(cell_types);
+    }
+    virtual typename R::BelBucketRangeT getBelBuckets() const override
+    {
+        NPNR_ASSERT(bel_buckets_initialised);
+        return return_if_match<const std::vector<BelBucketId> &, typename R::BelBucketRangeT>(bel_buckets);
+    }
+    virtual typename R::BucketBelRangeT getBelsInBucket(BelBucketId bucket) const override
+    {
+        NPNR_ASSERT(bel_buckets_initialised);
+        return return_if_match<const std::vector<BelId> &, typename R::BucketBelRangeT>(bucket_bels.at(bucket));
+    }
+
+    // Cluster methods
+    virtual CellInfo *getClusterRootCell(ClusterId cluster) const override { return get_cluster_root(this, cluster); }
+
+    virtual ArcBounds getClusterBounds(ClusterId cluster) const override
+    {
+        return if_using_basecluster<ArcBounds>(get_cluster_root(this, cluster), [](const BaseClusterInfo *cluster) {
+            ArcBounds bounds(0, 0, 0, 0);
+            for (auto child : cluster->constr_children) {
+                if_using_basecluster<void>(child, [&](const BaseClusterInfo *child) {
+                    bounds.x0 = std::min(bounds.x0, child->constr_x);
+                    bounds.y0 = std::min(bounds.y0, child->constr_y);
+                    bounds.x1 = std::max(bounds.x1, child->constr_x);
+                    bounds.y1 = std::max(bounds.y1, child->constr_y);
+                });
+            }
+            return bounds;
+        });
+    }
+
+    virtual Loc getClusterOffset(const CellInfo *cell) const override
+    {
+        return if_using_basecluster<Loc>(cell,
+                                         [](const BaseClusterInfo *c) { return Loc(c->constr_x, c->constr_y, 0); });
+    }
+
+    virtual bool isClusterStrict(const CellInfo *cell) const override { return true; }
+
+    virtual bool getClusterPlacement(ClusterId cluster, BelId root_bel,
+                                     std::vector<std::pair<CellInfo *, BelId>> &placement) const override
+    {
+        CellInfo *root_cell = get_cluster_root(this, cluster);
+        return if_using_basecluster<bool>(root_cell, [&](const BaseClusterInfo *cluster) -> bool {
+            placement.clear();
+            NPNR_ASSERT(root_bel != BelId());
+            Loc root_loc = this->getBelLocation(root_bel);
+
+            if (cluster->constr_abs_z) {
+                // Coerce root to absolute z constraint
+                root_loc.z = cluster->constr_z;
+                root_bel = this->getBelByLocation(root_loc);
+                if (root_bel == BelId() || !this->isValidBelForCellType(root_cell->type, root_bel))
+                    return false;
+            }
+            placement.emplace_back(root_cell, root_bel);
+
+            for (auto child : cluster->constr_children) {
+                Loc child_loc = if_using_basecluster<Loc>(child, [&](const BaseClusterInfo *child) {
+                    Loc result;
+                    result.x = root_loc.x + child->constr_x;
+                    result.y = root_loc.y + child->constr_y;
+                    result.z = child->constr_abs_z ? child->constr_z : (root_loc.z + child->constr_z);
+                    return result;
+                });
+                BelId child_bel = this->getBelByLocation(child_loc);
+                if (child_bel == BelId() || !this->isValidBelForCellType(child->type, child_bel))
+                    return false;
+                placement.emplace_back(child, child_bel);
+            }
+            return true;
+        });
+    }
+
+    // Flow methods
+    virtual void assignArchInfo() override{};
+
+    // --------------------------------------------------------------
+    // These structures are used to provide default implementations of bel/wire/pip binding. Arches might want to
+    // replace them with their own, for example to use faster access structures than dict. Arches might also
+    // want to add extra checks around these functions
+    dict<BelId, CellInfo *> base_bel2cell;
+    dict<WireId, NetInfo *> base_wire2net;
+    dict<PipId, NetInfo *> base_pip2net;
+
+    // For the default cell/bel bucket implementations
+    std::vector<IdString> cell_types;
+    std::vector<BelBucketId> bel_buckets;
+    dict<BelBucketId, std::vector<BelId>> bucket_bels;
+
+    // Arches that want to use the default cell types and bel buckets *must* call these functions in their constructor
+    bool cell_types_initialised = false;
+    bool bel_buckets_initialised = false;
+    void init_cell_types()
+    {
+        pool<IdString> bel_types;
+        for (auto bel : this->getBels())
+            bel_types.insert(this->getBelType(bel));
+        std::copy(bel_types.begin(), bel_types.end(), std::back_inserter(cell_types));
+        std::sort(cell_types.begin(), cell_types.end());
+        cell_types_initialised = true;
+    }
+    void init_bel_buckets()
+    {
+        for (auto cell_type : this->getCellTypes()) {
+            auto bucket = this->getBelBucketForCellType(cell_type);
+            bucket_bels[bucket]; // create empty bucket
+        }
+        for (auto bel : this->getBels()) {
+            auto bucket = this->getBelBucketForBel(bel);
+            bucket_bels[bucket].push_back(bel);
+        }
+        for (auto &b : bucket_bels)
+            bel_buckets.push_back(b.first);
+        std::sort(bel_buckets.begin(), bel_buckets.end());
+        bel_buckets_initialised = true;
+    }
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* BASE_ARCH_H */
diff --git a/common/kernel/base_clusterinfo.h b/common/kernel/base_clusterinfo.h
new file mode 100644
index 00000000..65e8e6d4
--- /dev/null
+++ b/common/kernel/base_clusterinfo.h
@@ -0,0 +1,45 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2021  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef BASE_CLUSTERINFO_H
+#define BASE_CLUSTERINFO_H
+
+#include "idstring.h"
+#include "nextpnr_namespaces.h"
+
+#include <vector>
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct CellInfo;
+
+// The 'legacy' cluster data, used for existing arches and to provide a basic implementation for arches without complex
+// clustering requirements
+struct BaseClusterInfo
+{
+    std::vector<CellInfo *> constr_children;
+    int constr_x = 0;          // this.x - parent.x
+    int constr_y = 0;          // this.y - parent.y
+    int constr_z = 0;          // this.z - parent.z
+    bool constr_abs_z = false; // parent.z := 0
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* BASE_ARCH_H */
diff --git a/common/kernel/basectx.cc b/common/kernel/basectx.cc
new file mode 100644
index 00000000..83a2deea
--- /dev/null
+++ b/common/kernel/basectx.cc
@@ -0,0 +1,279 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "basectx.h"
+
+#include <boost/algorithm/string.hpp>
+
+#include "context.h"
+#include "log.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+const char *BaseCtx::nameOfBel(BelId bel) const
+{
+    const Context *ctx = getCtx();
+    std::string &s = ctx->log_strs.next();
+    ctx->getBelName(bel).build_str(ctx, s);
+    return s.c_str();
+}
+
+const char *BaseCtx::nameOfWire(WireId wire) const
+{
+    const Context *ctx = getCtx();
+    std::string &s = ctx->log_strs.next();
+    ctx->getWireName(wire).build_str(ctx, s);
+    return s.c_str();
+}
+
+const char *BaseCtx::nameOfPip(PipId pip) const
+{
+    const Context *ctx = getCtx();
+    std::string &s = ctx->log_strs.next();
+    ctx->getPipName(pip).build_str(ctx, s);
+    return s.c_str();
+}
+
+const char *BaseCtx::nameOfGroup(GroupId group) const
+{
+    const Context *ctx = getCtx();
+    std::string &s = ctx->log_strs.next();
+    ctx->getGroupName(group).build_str(ctx, s);
+    return s.c_str();
+}
+
+BelId BaseCtx::getBelByNameStr(const std::string &str)
+{
+    Context *ctx = getCtx();
+    return ctx->getBelByName(IdStringList::parse(ctx, str));
+}
+
+WireId BaseCtx::getWireByNameStr(const std::string &str)
+{
+    Context *ctx = getCtx();
+    return ctx->getWireByName(IdStringList::parse(ctx, str));
+}
+
+PipId BaseCtx::getPipByNameStr(const std::string &str)
+{
+    Context *ctx = getCtx();
+    return ctx->getPipByName(IdStringList::parse(ctx, str));
+}
+
+GroupId BaseCtx::getGroupByNameStr(const std::string &str)
+{
+    Context *ctx = getCtx();
+    return ctx->getGroupByName(IdStringList::parse(ctx, str));
+}
+
+void BaseCtx::addClock(IdString net, float freq)
+{
+    std::unique_ptr<ClockConstraint> cc(new ClockConstraint());
+    cc->period = DelayPair(getCtx()->getDelayFromNS(1000 / freq));
+    cc->high = DelayPair(getCtx()->getDelayFromNS(500 / freq));
+    cc->low = DelayPair(getCtx()->getDelayFromNS(500 / freq));
+    if (!net_aliases.count(net)) {
+        log_warning("net '%s' does not exist in design, ignoring clock constraint\n", net.c_str(this));
+    } else {
+        getNetByAlias(net)->clkconstr = std::move(cc);
+        log_info("constraining clock net '%s' to %.02f MHz\n", net.c_str(this), freq);
+    }
+}
+
+void BaseCtx::createRectangularRegion(IdString name, int x0, int y0, int x1, int y1)
+{
+    std::unique_ptr<Region> new_region(new Region());
+    new_region->name = name;
+    new_region->constr_bels = true;
+    new_region->constr_pips = false;
+    new_region->constr_wires = false;
+    for (int x = x0; x <= x1; x++) {
+        for (int y = y0; y <= y1; y++) {
+            for (auto bel : getCtx()->getBelsByTile(x, y))
+                new_region->bels.insert(bel);
+        }
+    }
+    region[name] = std::move(new_region);
+}
+void BaseCtx::addBelToRegion(IdString name, BelId bel) { region[name]->bels.insert(bel); }
+void BaseCtx::constrainCellToRegion(IdString cell, IdString region_name)
+{
+    // Support hierarchical cells as well as leaf ones
+    bool matched = false;
+    if (hierarchy.count(cell)) {
+        auto &hc = hierarchy.at(cell);
+        for (auto &lc : hc.leaf_cells)
+            constrainCellToRegion(lc.second, region_name);
+        for (auto &hsc : hc.hier_cells)
+            constrainCellToRegion(hsc.second, region_name);
+        matched = true;
+    }
+    if (cells.count(cell)) {
+        cells.at(cell)->region = region[region_name].get();
+        matched = true;
+    }
+    if (!matched)
+        log_warning("No cell matched '%s' when constraining to region '%s'\n", nameOf(cell), nameOf(region_name));
+}
+DecalXY BaseCtx::constructDecalXY(DecalId decal, float x, float y)
+{
+    DecalXY dxy;
+    dxy.decal = decal;
+    dxy.x = x;
+    dxy.y = y;
+    return dxy;
+}
+
+void BaseCtx::archInfoToAttributes()
+{
+    for (auto &cell : cells) {
+        auto ci = cell.second.get();
+        if (ci->bel != BelId()) {
+            if (ci->attrs.find(id("BEL")) != ci->attrs.end()) {
+                ci->attrs.erase(ci->attrs.find(id("BEL")));
+            }
+            ci->attrs[id("NEXTPNR_BEL")] = getCtx()->getBelName(ci->bel).str(getCtx());
+            ci->attrs[id("BEL_STRENGTH")] = (int)ci->belStrength;
+        }
+    }
+    for (auto &net : getCtx()->nets) {
+        auto ni = net.second.get();
+        std::string routing;
+        bool first = true;
+        for (auto &item : ni->wires) {
+            if (!first)
+                routing += ";";
+            routing += getCtx()->getWireName(item.first).str(getCtx());
+            routing += ";";
+            if (item.second.pip != PipId())
+                routing += getCtx()->getPipName(item.second.pip).str(getCtx());
+            routing += ";" + std::to_string(item.second.strength);
+            first = false;
+        }
+        ni->attrs[id("ROUTING")] = routing;
+    }
+}
+
+void BaseCtx::attributesToArchInfo()
+{
+    for (auto &cell : cells) {
+        auto ci = cell.second.get();
+        auto val = ci->attrs.find(id("NEXTPNR_BEL"));
+        if (val != ci->attrs.end()) {
+            auto str = ci->attrs.find(id("BEL_STRENGTH"));
+            PlaceStrength strength = PlaceStrength::STRENGTH_USER;
+            if (str != ci->attrs.end())
+                strength = (PlaceStrength)str->second.as_int64();
+
+            BelId b = getCtx()->getBelByNameStr(val->second.as_string());
+            getCtx()->bindBel(b, ci, strength);
+        }
+    }
+    for (auto &net : getCtx()->nets) {
+        auto ni = net.second.get();
+        auto val = ni->attrs.find(id("ROUTING"));
+        if (val != ni->attrs.end()) {
+            std::vector<std::string> strs;
+            auto routing = val->second.as_string();
+            boost::split(strs, routing, boost::is_any_of(";"));
+            for (size_t i = 0; i < strs.size() / 3; i++) {
+                std::string wire = strs[i * 3];
+                std::string pip = strs[i * 3 + 1];
+                PlaceStrength strength = (PlaceStrength)std::stoi(strs[i * 3 + 2]);
+                if (pip.empty())
+                    getCtx()->bindWire(getCtx()->getWireByName(IdStringList::parse(getCtx(), wire)), ni, strength);
+                else
+                    getCtx()->bindPip(getCtx()->getPipByName(IdStringList::parse(getCtx(), pip)), ni, strength);
+            }
+        }
+    }
+    getCtx()->assignArchInfo();
+}
+
+NetInfo *BaseCtx::createNet(IdString name)
+{
+    NPNR_ASSERT(!nets.count(name));
+    NPNR_ASSERT(!net_aliases.count(name));
+    auto net = std::make_unique<NetInfo>(name);
+    net_aliases[name] = name;
+    NetInfo *ptr = net.get();
+    nets[name] = std::move(net);
+    refreshUi();
+    return ptr;
+}
+
+void BaseCtx::connectPort(IdString net, IdString cell, IdString port)
+{
+    NetInfo *net_info = getNetByAlias(net);
+    CellInfo *cell_info = cells.at(cell).get();
+    cell_info->connectPort(port, net_info);
+}
+
+void BaseCtx::disconnectPort(IdString cell, IdString port)
+{
+    CellInfo *cell_info = cells.at(cell).get();
+    cell_info->disconnectPort(port);
+}
+
+void BaseCtx::renameNet(IdString old_name, IdString new_name)
+{
+    NetInfo *net = nets.at(old_name).get();
+    NPNR_ASSERT(!nets.count(new_name));
+    nets[new_name];
+    std::swap(nets.at(net->name), nets.at(new_name));
+    nets.erase(net->name);
+    net->name = new_name;
+}
+
+void BaseCtx::ripupNet(IdString name)
+{
+    NetInfo *net_info = getNetByAlias(name);
+    std::vector<WireId> to_unbind;
+    for (auto &wire : net_info->wires)
+        to_unbind.push_back(wire.first);
+    for (auto &unbind : to_unbind)
+        getCtx()->unbindWire(unbind);
+}
+void BaseCtx::lockNetRouting(IdString name)
+{
+    NetInfo *net_info = getNetByAlias(name);
+    for (auto &wire : net_info->wires)
+        wire.second.strength = STRENGTH_USER;
+}
+
+CellInfo *BaseCtx::createCell(IdString name, IdString type)
+{
+    NPNR_ASSERT(!cells.count(name));
+    auto cell = std::make_unique<CellInfo>(getCtx(), name, type);
+    CellInfo *ptr = cell.get();
+    cells[name] = std::move(cell);
+    refreshUi();
+    return ptr;
+}
+
+void BaseCtx::copyBelPorts(IdString cell, BelId bel)
+{
+    CellInfo *cell_info = cells.at(cell).get();
+    for (auto pin : getCtx()->getBelPins(bel)) {
+        cell_info->ports[pin].name = pin;
+        cell_info->ports[pin].type = getCtx()->getBelPinType(bel, pin);
+    }
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/basectx.h b/common/kernel/basectx.h
new file mode 100644
index 00000000..21d6d63a
--- /dev/null
+++ b/common/kernel/basectx.h
@@ -0,0 +1,243 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef BASECTX_H
+#define BASECTX_H
+
+#include <mutex>
+#include <unordered_map>
+#include <vector>
+#ifndef NPNR_DISABLE_THREADS
+#include <boost/thread.hpp>
+#endif
+
+#include "hashlib.h"
+#include "idstring.h"
+#include "nextpnr_namespaces.h"
+#include "nextpnr_types.h"
+#include "property.h"
+#include "str_ring_buffer.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct Context;
+
+struct BaseCtx
+{
+#ifndef NPNR_DISABLE_THREADS
+    // Lock to perform mutating actions on the Context.
+    std::mutex mutex;
+    boost::thread::id mutex_owner;
+
+    // Lock to be taken by UI when wanting to access context - the yield()
+    // method will lock/unlock it when its' released the main mutex to make
+    // sure the UI is not starved.
+    std::mutex ui_mutex;
+#endif
+
+    // ID String database.
+    mutable std::unordered_map<std::string, int> *idstring_str_to_idx;
+    mutable std::vector<const std::string *> *idstring_idx_to_str;
+
+    // Temporary string backing store for logging
+    mutable StrRingBuffer log_strs;
+
+    // Project settings and config switches
+    dict<IdString, Property> settings;
+
+    // Placed nets and cells.
+    dict<IdString, std::unique_ptr<NetInfo>> nets;
+    dict<IdString, std::unique_ptr<CellInfo>> cells;
+
+    // Hierarchical (non-leaf) cells by full path
+    dict<IdString, HierarchicalCell> hierarchy;
+    // This is the root of the above structure
+    IdString top_module;
+
+    // Aliases for nets, which may have more than one name due to assignments and hierarchy
+    dict<IdString, IdString> net_aliases;
+
+    // Top-level ports
+    dict<IdString, PortInfo> ports;
+    dict<IdString, CellInfo *> port_cells;
+
+    // Floorplanning regions
+    dict<IdString, std::unique_ptr<Region>> region;
+
+    // Context meta data
+    dict<IdString, Property> attrs;
+
+    // Fmax data post timing analysis
+    TimingResult timing_result;
+
+    Context *as_ctx = nullptr;
+
+    // Has the frontend loaded a design?
+    bool design_loaded;
+
+    BaseCtx()
+    {
+        idstring_str_to_idx = new std::unordered_map<std::string, int>;
+        idstring_idx_to_str = new std::vector<const std::string *>;
+        IdString::initialize_add(this, "", 0);
+        IdString::initialize_arch(this);
+
+        design_loaded = false;
+    }
+
+    virtual ~BaseCtx()
+    {
+        delete idstring_str_to_idx;
+        delete idstring_idx_to_str;
+    }
+
+    // Must be called before performing any mutating changes on the Ctx/Arch.
+    void lock(void)
+    {
+#ifndef NPNR_DISABLE_THREADS
+        mutex.lock();
+        mutex_owner = boost::this_thread::get_id();
+#endif
+    }
+
+    void unlock(void)
+    {
+#ifndef NPNR_DISABLE_THREADS
+        NPNR_ASSERT(boost::this_thread::get_id() == mutex_owner);
+        mutex.unlock();
+#endif
+    }
+
+    // Must be called by the UI before rendering data. This lock will be
+    // prioritized when processing code calls yield().
+    void lock_ui(void)
+    {
+#ifndef NPNR_DISABLE_THREADS
+        ui_mutex.lock();
+        mutex.lock();
+#endif
+    }
+
+    void unlock_ui(void)
+    {
+#ifndef NPNR_DISABLE_THREADS
+        mutex.unlock();
+        ui_mutex.unlock();
+#endif
+    }
+
+    // Yield to UI by unlocking the main mutex, flashing the UI mutex and
+    // relocking the main mutex. Call this when you're performing a
+    // long-standing action while holding a lock to let the UI show
+    // visualization updates.
+    // Must be called with the main lock taken.
+    void yield(void)
+    {
+#ifndef NPNR_DISABLE_THREADS
+        unlock();
+        ui_mutex.lock();
+        ui_mutex.unlock();
+        lock();
+#endif
+    }
+
+    IdString id(const std::string &s) const { return IdString(this, s); }
+
+    IdString id(const char *s) const { return IdString(this, s); }
+
+    Context *getCtx() { return as_ctx; }
+
+    const Context *getCtx() const { return as_ctx; }
+
+    const char *nameOf(IdString name) const { return name.c_str(this); }
+
+    template <typename T> const char *nameOf(const T *obj) const
+    {
+        if (obj == nullptr)
+            return "";
+        return obj->name.c_str(this);
+    }
+
+    const char *nameOfBel(BelId bel) const;
+    const char *nameOfWire(WireId wire) const;
+    const char *nameOfPip(PipId pip) const;
+    const char *nameOfGroup(GroupId group) const;
+
+    // Wrappers of arch functions that take a string and handle IdStringList parsing
+    BelId getBelByNameStr(const std::string &str);
+    WireId getWireByNameStr(const std::string &str);
+    PipId getPipByNameStr(const std::string &str);
+    GroupId getGroupByNameStr(const std::string &str);
+
+    // --------------------------------------------------------------
+
+    bool allUiReload = true;
+    bool frameUiReload = false;
+    pool<BelId> belUiReload;
+    pool<WireId> wireUiReload;
+    pool<PipId> pipUiReload;
+    pool<GroupId> groupUiReload;
+
+    void refreshUi() { allUiReload = true; }
+
+    void refreshUiFrame() { frameUiReload = true; }
+
+    void refreshUiBel(BelId bel) { belUiReload.insert(bel); }
+
+    void refreshUiWire(WireId wire) { wireUiReload.insert(wire); }
+
+    void refreshUiPip(PipId pip) { pipUiReload.insert(pip); }
+
+    void refreshUiGroup(GroupId group) { groupUiReload.insert(group); }
+
+    // --------------------------------------------------------------
+
+    NetInfo *getNetByAlias(IdString alias) const
+    {
+        return nets.count(alias) ? nets.at(alias).get() : nets.at(net_aliases.at(alias)).get();
+    }
+
+    // Intended to simplify Python API
+    void addClock(IdString net, float freq);
+    void createRectangularRegion(IdString name, int x0, int y0, int x1, int y1);
+    void addBelToRegion(IdString name, BelId bel);
+    void constrainCellToRegion(IdString cell, IdString region_name);
+
+    // Helper functions for Python bindings
+    NetInfo *createNet(IdString name);
+    void connectPort(IdString net, IdString cell, IdString port);
+    void disconnectPort(IdString cell, IdString port);
+    void ripupNet(IdString name);
+    void lockNetRouting(IdString name);
+    void renameNet(IdString old_name, IdString new_name);
+
+    CellInfo *createCell(IdString name, IdString type);
+    void copyBelPorts(IdString cell, BelId bel);
+
+    // Workaround for lack of wrappable constructors
+    DecalXY constructDecalXY(DecalId decal, float x, float y);
+
+    void archInfoToAttributes();
+    void attributesToArchInfo();
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* BASECTX_H */
diff --git a/common/kernel/bits.cc b/common/kernel/bits.cc
new file mode 100644
index 00000000..b20c2e86
--- /dev/null
+++ b/common/kernel/bits.cc
@@ -0,0 +1,56 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (c) 2013  Mike Pedersen
+ *  Copyright (C) 2021  Symbiflow Authors
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "bits.h"
+
+#include <limits>
+#include <stdexcept>
+
+#include "log.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+int Bits::generic_popcount(unsigned int v)
+{
+    unsigned int c; // c accumulates the total bits set in v
+    for (c = 0; v; c++) {
+        v &= v - 1; // clear the least significant bit set
+    }
+
+    return c;
+}
+
+int Bits::generic_ctz(unsigned int x)
+{
+    if (x == 0) {
+        log_error("Cannot call ctz with arg = 0");
+    }
+
+    for (size_t i = 0; i < std::numeric_limits<unsigned int>::digits; ++i) {
+        if ((x & (1 << i)) != 0) {
+            return i;
+        }
+    }
+
+    // Unreachable!
+    log_error("Unreachable!");
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/bits.h b/common/kernel/bits.h
new file mode 100644
index 00000000..04b25b74
--- /dev/null
+++ b/common/kernel/bits.h
@@ -0,0 +1,76 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (c) 2013  Mike Pedersen
+ *  Copyright (C) 2021  Symbiflow Authors
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+// This is a small library for implementing common bit vector utilities,
+// namely:
+//
+//  - popcount : The number of bits set in an unsigned int
+//  - ctz : The number of trailing zero bits in an unsigned int.
+//          Must be called with a value that has at least 1 bit set.
+//
+// These methods will typically use instrinics when available, and have a
+// generic fallback in the event that the instrinic is not available.
+//
+// If clz (count leading zeros) is needed, it can be added when needed.
+#ifndef BITS_H
+#define BITS_H
+
+#if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_IX86))
+#include <intrin.h>
+#pragma intrinsic(_BitScanForward, _BitScanReverse, __popcnt)
+#endif
+
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct Bits
+{
+    static int generic_popcount(unsigned int x);
+    static int generic_ctz(unsigned int x);
+
+    static int popcount(unsigned int x)
+    {
+#if defined(__GNUC__) || defined(__clang__)
+        return __builtin_popcount(x);
+#elif defined(_MSC_VER) && (defined(_M_X64) || defined(_M_IX86))
+        return __popcnt(x);
+#else
+        return generic_popcount(x);
+#endif
+    }
+
+    static int ctz(unsigned int x)
+    {
+#if defined(__GNUC__) || defined(__clang__)
+        return __builtin_ctz(x);
+#elif defined(_MSC_VER) && (defined(_M_X64) || defined(_M_IX86))
+        unsigned long result;
+        _BitScanForward(&result, x);
+        return result;
+#else
+        return generic_ctz(x);
+#endif
+    }
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* BITS_H */
diff --git a/common/kernel/chain_utils.h b/common/kernel/chain_utils.h
new file mode 100644
index 00000000..ca8a1be3
--- /dev/null
+++ b/common/kernel/chain_utils.h
@@ -0,0 +1,69 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef CHAIN_UTILS_H
+#define CHAIN_UTILS_H
+
+#include "nextpnr.h"
+#include "util.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct CellChain
+{
+    std::vector<CellInfo *> cells;
+};
+
+// Generic chain finder
+template <typename F1, typename F2, typename F3>
+std::vector<CellChain> find_chains(const Context *ctx, F1 cell_type_predicate, F2 get_previous, F3 get_next,
+                                   size_t min_length = 2)
+{
+    std::set<IdString> chained;
+    std::vector<CellChain> chains;
+    for (auto &cell : ctx->cells) {
+        if (chained.find(cell.first) != chained.end())
+            continue;
+        CellInfo *ci = cell.second.get();
+        if (cell_type_predicate(ctx, ci)) {
+            CellInfo *start = ci;
+            CellInfo *prev_start = ci;
+            while (prev_start != nullptr) {
+                start = prev_start;
+                prev_start = get_previous(ctx, start);
+            }
+            CellChain chain;
+            CellInfo *end = start;
+            while (end != nullptr) {
+                if (chained.insert(end->name).second)
+                    chain.cells.push_back(end);
+                end = get_next(ctx, end);
+            }
+            if (chain.cells.size() >= min_length) {
+                chains.push_back(chain);
+                for (auto c : chain.cells)
+                    chained.insert(c->name);
+            }
+        }
+    }
+    return chains;
+}
+
+NEXTPNR_NAMESPACE_END
+#endif
diff --git a/common/kernel/command.cc b/common/kernel/command.cc
new file mode 100644
index 00000000..00f900b3
--- /dev/null
+++ b/common/kernel/command.cc
@@ -0,0 +1,563 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Miodrag Milanovic <micko@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef NO_GUI
+#include <QApplication>
+#include "application.h"
+#include "mainwindow.h"
+#endif
+#ifndef NO_PYTHON
+#include "pybindings.h"
+#endif
+
+#include <boost/algorithm/string.hpp>
+#include <boost/algorithm/string/join.hpp>
+#include <boost/filesystem/convenience.hpp>
+#include <boost/program_options.hpp>
+#include <fstream>
+#include <iostream>
+#include <random>
+#include "command.h"
+#include "design_utils.h"
+#include "json_frontend.h"
+#include "jsonwrite.h"
+#include "log.h"
+#include "timing.h"
+#include "util.h"
+#include "version.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct no_separator : std::numpunct<char>
+{
+  protected:
+    virtual string_type do_grouping() const { return "\000"; } // groups of 0 (disable)
+};
+
+CommandHandler::CommandHandler(int argc, char **argv) : argc(argc), argv(argv)
+{
+    try {
+        std::locale loc("");
+        std::locale::global(std::locale(loc, new no_separator()));
+    } catch (const std::runtime_error &e) {
+        // the locale is broken in this system, so leave it as it is
+    }
+    log_streams.clear();
+}
+
+bool CommandHandler::parseOptions()
+{
+    options.add(getGeneralOptions()).add(getArchOptions());
+    try {
+        po::parsed_options parsed =
+                po::command_line_parser(argc, argv)
+                        .style(po::command_line_style::default_style ^ po::command_line_style::allow_guessing)
+                        .options(options)
+                        .positional(pos)
+                        .run();
+        po::store(parsed, vm);
+        po::notify(vm);
+        return true;
+    } catch (std::exception &e) {
+        std::cout << e.what() << "\n";
+        return false;
+    }
+}
+
+bool CommandHandler::executeBeforeContext()
+{
+    if (vm.count("help") || argc == 1) {
+        std::cerr << boost::filesystem::basename(argv[0])
+                  << " -- Next Generation Place and Route (Version " GIT_DESCRIBE_STR ")\n";
+        std::cerr << options << "\n";
+        return argc != 1;
+    }
+
+    if (vm.count("version")) {
+        std::cerr << boost::filesystem::basename(argv[0])
+                  << " -- Next Generation Place and Route (Version " GIT_DESCRIBE_STR ")\n";
+        return true;
+    }
+    validate();
+
+    if (vm.count("quiet")) {
+        log_streams.push_back(std::make_pair(&std::cerr, LogLevel::WARNING_MSG));
+    } else {
+        log_streams.push_back(std::make_pair(&std::cerr, LogLevel::LOG_MSG));
+    }
+
+    if (vm.count("log")) {
+        std::string logfilename = vm["log"].as<std::string>();
+        logfile.open(logfilename);
+        if (!logfile.is_open())
+            log_error("Failed to open log file '%s' for writing.\n", logfilename.c_str());
+        log_streams.push_back(std::make_pair(&logfile, LogLevel::LOG_MSG));
+    }
+    return false;
+}
+
+po::options_description CommandHandler::getGeneralOptions()
+{
+    po::options_description general("General options");
+    general.add_options()("help,h", "show help");
+    general.add_options()("verbose,v", "verbose output");
+    general.add_options()("quiet,q", "quiet mode, only errors and warnings displayed");
+    general.add_options()("log,l", po::value<std::string>(),
+                          "log file, all log messages are written to this file regardless of -q");
+    general.add_options()("debug", "debug output");
+    general.add_options()("debug-placer", "debug output from placer only");
+    general.add_options()("debug-router", "debug output from router only");
+    general.add_options()("threads", po::value<int>(), "number of threads for passes where this is configurable");
+
+    general.add_options()("force,f", "keep running after errors");
+#ifndef NO_GUI
+    general.add_options()("gui", "start gui");
+    general.add_options()("gui-no-aa", "disable anti aliasing (use together with --gui option)");
+#endif
+#ifndef NO_PYTHON
+    general.add_options()("run", po::value<std::vector<std::string>>(),
+                          "python file to execute instead of default flow");
+    pos.add("run", -1);
+    general.add_options()("pre-pack", po::value<std::vector<std::string>>(), "python file to run before packing");
+    general.add_options()("pre-place", po::value<std::vector<std::string>>(), "python file to run before placement");
+    general.add_options()("pre-route", po::value<std::vector<std::string>>(), "python file to run before routing");
+    general.add_options()("post-route", po::value<std::vector<std::string>>(), "python file to run after routing");
+    general.add_options()("on-failure", po::value<std::vector<std::string>>(),
+                          "python file to run in event of crash for design introspection");
+
+#endif
+    general.add_options()("json", po::value<std::string>(), "JSON design file to ingest");
+    general.add_options()("write", po::value<std::string>(), "JSON design file to write");
+    general.add_options()("top", po::value<std::string>(), "name of top module");
+    general.add_options()("seed", po::value<int>(), "seed value for random number generator");
+    general.add_options()("randomize-seed,r", "randomize seed value for random number generator");
+
+    general.add_options()(
+            "placer", po::value<std::string>(),
+            std::string("placer algorithm to use; available: " + boost::algorithm::join(Arch::availablePlacers, ", ") +
+                        "; default: " + Arch::defaultPlacer)
+                    .c_str());
+
+    general.add_options()(
+            "router", po::value<std::string>(),
+            std::string("router algorithm to use; available: " + boost::algorithm::join(Arch::availableRouters, ", ") +
+                        "; default: " + Arch::defaultRouter)
+                    .c_str());
+
+    general.add_options()("slack_redist_iter", po::value<int>(), "number of iterations between slack redistribution");
+    general.add_options()("cstrweight", po::value<float>(), "placer weighting for relative constraint satisfaction");
+    general.add_options()("starttemp", po::value<float>(), "placer SA start temperature");
+    general.add_options()("placer-budgets", "use budget rather than criticality in placer timing weights");
+
+    general.add_options()("pack-only", "pack design only without placement or routing");
+    general.add_options()("no-route", "process design without routing");
+    general.add_options()("no-place", "process design without placement");
+    general.add_options()("no-pack", "process design without packing");
+
+    general.add_options()("ignore-loops", "ignore combinational loops in timing analysis");
+
+    general.add_options()("version,V", "show version");
+    general.add_options()("test", "check architecture database integrity");
+    general.add_options()("freq", po::value<double>(), "set target frequency for design in MHz");
+    general.add_options()("timing-allow-fail", "allow timing to fail in design");
+    general.add_options()("no-tmdriv", "disable timing-driven placement");
+    general.add_options()("sdf", po::value<std::string>(), "SDF delay back-annotation file to write");
+    general.add_options()("sdf-cvc", "enable tweaks for SDF file compatibility with the CVC simulator");
+    general.add_options()("no-print-critical-path-source",
+                          "disable printing of the line numbers associated with each net in the critical path");
+
+    general.add_options()("placer-heap-alpha", po::value<float>(), "placer heap alpha value (float, default: 0.1)");
+    general.add_options()("placer-heap-beta", po::value<float>(), "placer heap beta value (float, default: 0.9)");
+    general.add_options()("placer-heap-critexp", po::value<int>(),
+                          "placer heap criticality exponent (int, default: 2)");
+    general.add_options()("placer-heap-timingweight", po::value<int>(), "placer heap timing weight (int, default: 10)");
+
+#if !defined(__wasm)
+    general.add_options()("parallel-refine", "use new experimental parallelised engine for placement refinement");
+#endif
+
+    general.add_options()("router2-heatmap", po::value<std::string>(),
+                          "prefix for router2 resource congestion heatmaps");
+
+    general.add_options()("tmg-ripup", "enable experimental timing-driven ripup in router");
+    general.add_options()("router2-tmg-ripup",
+                          "enable experimental timing-driven ripup in router (deprecated; use --tmg-ripup instead)");
+
+    general.add_options()("report", po::value<std::string>(),
+                          "write timing and utilization report in JSON format to file");
+    general.add_options()("detailed-timing-report", "Append detailed net timing data to the JSON report");
+
+    general.add_options()("placed-svg", po::value<std::string>(), "write render of placement to SVG file");
+    general.add_options()("routed-svg", po::value<std::string>(), "write render of routing to SVG file");
+
+    return general;
+}
+
+namespace {
+static CommandHandler *global_command_handler = nullptr;
+void script_terminate_handler()
+{
+    if (global_command_handler != nullptr)
+        global_command_handler->run_script_hook("on-failure");
+}
+}; // namespace
+
+void CommandHandler::setupContext(Context *ctx)
+{
+    if (ctx->settings.find(ctx->id("seed")) != ctx->settings.end())
+        ctx->rngstate = ctx->setting<uint64_t>("seed");
+
+    if (vm.count("verbose")) {
+        ctx->verbose = true;
+    }
+
+    if (vm.count("debug")) {
+        ctx->verbose = true;
+        ctx->debug = true;
+    }
+
+    if (vm.count("no-print-critical-path-source")) {
+        ctx->disable_critical_path_source_print = true;
+    }
+
+    if (vm.count("force")) {
+        ctx->force = true;
+    }
+
+    if (vm.count("seed")) {
+        ctx->rngseed(vm["seed"].as<int>());
+    }
+
+    if (vm.count("threads")) {
+        ctx->settings[ctx->id("threads")] = vm["threads"].as<int>();
+    }
+
+    if (vm.count("randomize-seed")) {
+        std::random_device randDev{};
+        std::uniform_int_distribution<int> distrib{1};
+        ctx->rngseed(distrib(randDev));
+    }
+
+    if (vm.count("slack_redist_iter")) {
+        ctx->settings[ctx->id("slack_redist_iter")] = vm["slack_redist_iter"].as<int>();
+        if (vm.count("freq") && vm["freq"].as<double>() == 0) {
+            ctx->settings[ctx->id("auto_freq")] = true;
+#ifndef NO_GUI
+            if (!vm.count("gui"))
+#endif
+                log_warning("Target frequency not specified. Will optimise for max frequency.\n");
+        }
+    }
+
+    if (vm.count("ignore-loops")) {
+        ctx->settings[ctx->id("timing/ignoreLoops")] = true;
+    }
+
+    if (vm.count("timing-allow-fail")) {
+        ctx->settings[ctx->id("timing/allowFail")] = true;
+    }
+
+    if (vm.count("placer")) {
+        std::string placer = vm["placer"].as<std::string>();
+        if (std::find(Arch::availablePlacers.begin(), Arch::availablePlacers.end(), placer) ==
+            Arch::availablePlacers.end())
+            log_error("Placer algorithm '%s' is not supported (available options: %s)\n", placer.c_str(),
+                      boost::algorithm::join(Arch::availablePlacers, ", ").c_str());
+        ctx->settings[ctx->id("placer")] = placer;
+    }
+
+    if (vm.count("router")) {
+        std::string router = vm["router"].as<std::string>();
+        if (std::find(Arch::availableRouters.begin(), Arch::availableRouters.end(), router) ==
+            Arch::availableRouters.end())
+            log_error("Router algorithm '%s' is not supported (available options: %s)\n", router.c_str(),
+                      boost::algorithm::join(Arch::availableRouters, ", ").c_str());
+        ctx->settings[ctx->id("router")] = router;
+    }
+
+    if (vm.count("cstrweight")) {
+        ctx->settings[ctx->id("placer1/constraintWeight")] = std::to_string(vm["cstrweight"].as<float>());
+    }
+    if (vm.count("starttemp")) {
+        ctx->settings[ctx->id("placer1/startTemp")] = std::to_string(vm["starttemp"].as<float>());
+    }
+
+    if (vm.count("placer-budgets")) {
+        ctx->settings[ctx->id("placer1/budgetBased")] = true;
+    }
+    if (vm.count("freq")) {
+        auto freq = vm["freq"].as<double>();
+        if (freq > 0)
+            ctx->settings[ctx->id("target_freq")] = std::to_string(freq * 1e6);
+    }
+
+    if (vm.count("no-tmdriv"))
+        ctx->settings[ctx->id("timing_driven")] = false;
+
+    if (vm.count("placer-heap-alpha"))
+        ctx->settings[ctx->id("placerHeap/alpha")] = std::to_string(vm["placer-heap-alpha"].as<float>());
+
+    if (vm.count("placer-heap-beta"))
+        ctx->settings[ctx->id("placerHeap/beta")] = std::to_string(vm["placer-heap-beta"].as<float>());
+
+    if (vm.count("placer-heap-critexp"))
+        ctx->settings[ctx->id("placerHeap/criticalityExponent")] = std::to_string(vm["placer-heap-critexp"].as<int>());
+
+    if (vm.count("placer-heap-timingweight"))
+        ctx->settings[ctx->id("placerHeap/timingWeight")] = std::to_string(vm["placer-heap-timingweight"].as<int>());
+
+    if (vm.count("parallel-refine"))
+        ctx->settings[ctx->id("placerHeap/parallelRefine")] = true;
+
+    if (vm.count("router2-heatmap"))
+        ctx->settings[ctx->id("router2/heatmap")] = vm["router2-heatmap"].as<std::string>();
+    if (vm.count("tmg-ripup") || vm.count("router2-tmg-ripup"))
+        ctx->settings[ctx->id("router/tmg_ripup")] = true;
+
+    // Setting default values
+    if (ctx->settings.find(ctx->id("target_freq")) == ctx->settings.end())
+        ctx->settings[ctx->id("target_freq")] = std::to_string(12e6);
+    if (ctx->settings.find(ctx->id("timing_driven")) == ctx->settings.end())
+        ctx->settings[ctx->id("timing_driven")] = true;
+    if (ctx->settings.find(ctx->id("slack_redist_iter")) == ctx->settings.end())
+        ctx->settings[ctx->id("slack_redist_iter")] = 0;
+    if (ctx->settings.find(ctx->id("auto_freq")) == ctx->settings.end())
+        ctx->settings[ctx->id("auto_freq")] = false;
+    if (ctx->settings.find(ctx->id("placer")) == ctx->settings.end())
+        ctx->settings[ctx->id("placer")] = Arch::defaultPlacer;
+    if (ctx->settings.find(ctx->id("router")) == ctx->settings.end())
+        ctx->settings[ctx->id("router")] = Arch::defaultRouter;
+
+    ctx->settings[ctx->id("arch.name")] = std::string(ctx->archId().c_str(ctx));
+    ctx->settings[ctx->id("arch.type")] = std::string(ctx->archArgsToId(ctx->archArgs()).c_str(ctx));
+    ctx->settings[ctx->id("seed")] = ctx->rngstate;
+
+    if (ctx->settings.find(ctx->id("placerHeap/alpha")) == ctx->settings.end())
+        ctx->settings[ctx->id("placerHeap/alpha")] = std::to_string(0.1);
+    if (ctx->settings.find(ctx->id("placerHeap/beta")) == ctx->settings.end())
+        ctx->settings[ctx->id("placerHeap/beta")] = std::to_string(0.9);
+    if (ctx->settings.find(ctx->id("placerHeap/criticalityExponent")) == ctx->settings.end())
+        ctx->settings[ctx->id("placerHeap/criticalityExponent")] = std::to_string(2);
+    if (ctx->settings.find(ctx->id("placerHeap/timingWeight")) == ctx->settings.end())
+        ctx->settings[ctx->id("placerHeap/timingWeight")] = std::to_string(10);
+
+    if (vm.count("detailed-timing-report")) {
+        ctx->detailed_timing_report = true;
+    }
+}
+
+int CommandHandler::executeMain(std::unique_ptr<Context> ctx)
+{
+    if (vm.count("on-failure")) {
+        global_command_handler = this;
+        std::set_terminate(script_terminate_handler);
+    }
+    if (vm.count("test")) {
+        ctx->archcheck();
+        return 0;
+    }
+
+    if (vm.count("top")) {
+        ctx->settings[ctx->id("frontend/top")] = vm["top"].as<std::string>();
+    }
+
+#ifndef NO_GUI
+    if (vm.count("gui")) {
+        Application a(argc, argv, (vm.count("gui-no-aa") > 0));
+        MainWindow w(std::move(ctx), this);
+        try {
+            if (vm.count("json")) {
+                std::string filename = vm["json"].as<std::string>();
+                std::ifstream f(filename);
+                if (!parse_json(f, filename, w.getContext()))
+                    log_error("Loading design failed.\n");
+                customAfterLoad(w.getContext());
+                w.notifyChangeContext();
+                w.updateActions();
+            } else
+                w.notifyChangeContext();
+        } catch (log_execution_error_exception) {
+            // show error is handled by gui itself
+        }
+        w.show();
+
+        return a.exec();
+    }
+#endif
+    if (vm.count("json")) {
+        std::string filename = vm["json"].as<std::string>();
+        std::ifstream f(filename);
+        if (!parse_json(f, filename, ctx.get()))
+            log_error("Loading design failed.\n");
+
+        customAfterLoad(ctx.get());
+    }
+
+#ifndef NO_PYTHON
+    init_python(argv[0]);
+    python_export_global("ctx", *ctx);
+
+    if (vm.count("run")) {
+
+        std::vector<std::string> files = vm["run"].as<std::vector<std::string>>();
+        for (auto filename : files)
+            execute_python_file(filename.c_str());
+    } else
+#endif
+            if (ctx->design_loaded) {
+        bool do_pack = vm.count("pack-only") != 0 || vm.count("no-pack") == 0;
+        bool do_place = vm.count("pack-only") == 0 && vm.count("no-place") == 0;
+        bool do_route = vm.count("pack-only") == 0 && vm.count("no-route") == 0;
+
+        if (do_pack) {
+            run_script_hook("pre-pack");
+            if (!ctx->pack() && !ctx->force)
+                log_error("Packing design failed.\n");
+        }
+        assign_budget(ctx.get());
+        ctx->check();
+        print_utilisation(ctx.get());
+
+        if (do_place) {
+            run_script_hook("pre-place");
+            bool saved_debug = ctx->debug;
+            if (vm.count("debug-placer"))
+                ctx->debug = true;
+            if (!ctx->place() && !ctx->force)
+                log_error("Placing design failed.\n");
+            ctx->debug = saved_debug;
+            ctx->check();
+            if (vm.count("placed-svg"))
+                ctx->writeSVG(vm["placed-svg"].as<std::string>(), "scale=50 hide_routing");
+        }
+
+        if (do_route) {
+            run_script_hook("pre-route");
+            bool saved_debug = ctx->debug;
+            if (vm.count("debug-router"))
+                ctx->debug = true;
+            if (!ctx->route() && !ctx->force)
+                log_error("Routing design failed.\n");
+            ctx->debug = saved_debug;
+            run_script_hook("post-route");
+            if (vm.count("routed-svg"))
+                ctx->writeSVG(vm["routed-svg"].as<std::string>(), "scale=500");
+        }
+
+        customBitstream(ctx.get());
+    }
+
+    if (vm.count("write")) {
+        std::string filename = vm["write"].as<std::string>();
+        std::ofstream f(filename);
+        if (!write_json_file(f, filename, ctx.get()))
+            log_error("Saving design failed.\n");
+    }
+
+    if (vm.count("sdf")) {
+        std::string filename = vm["sdf"].as<std::string>();
+        std::ofstream f(filename);
+        if (!f)
+            log_error("Failed to open SDF file '%s' for writing.\n", filename.c_str());
+        ctx->writeSDF(f, vm.count("sdf-cvc"));
+    }
+
+    if (vm.count("report")) {
+        std::string filename = vm["report"].as<std::string>();
+        std::ofstream f(filename);
+        if (!f)
+            log_error("Failed to open report file '%s' for writing.\n", filename.c_str());
+        ctx->writeReport(f);
+    }
+
+#ifndef NO_PYTHON
+    deinit_python();
+#endif
+
+    return had_nonfatal_error ? 1 : 0;
+}
+
+void CommandHandler::conflicting_options(const boost::program_options::variables_map &vm, const char *opt1,
+                                         const char *opt2)
+{
+    if (vm.count(opt1) && !vm[opt1].defaulted() && vm.count(opt2) && !vm[opt2].defaulted()) {
+        std::string msg = "Conflicting options '" + std::string(opt1) + "' and '" + std::string(opt2) + "'.";
+        log_error("%s\n", msg.c_str());
+    }
+}
+
+void CommandHandler::printFooter()
+{
+    int warning_count = get_or_default(message_count_by_level, LogLevel::WARNING_MSG, 0),
+        error_count = get_or_default(message_count_by_level, LogLevel::ERROR_MSG, 0);
+    if (warning_count > 0 || error_count > 0)
+        log_always("%d warning%s, %d error%s\n", warning_count, warning_count == 1 ? "" : "s", error_count,
+                   error_count == 1 ? "" : "s");
+}
+
+int CommandHandler::exec()
+{
+    try {
+        if (!parseOptions())
+            return -1;
+
+        if (executeBeforeContext())
+            return 0;
+
+        dict<std::string, Property> values;
+        std::unique_ptr<Context> ctx = createContext(values);
+        setupContext(ctx.get());
+        setupArchContext(ctx.get());
+        int rc = executeMain(std::move(ctx));
+        printFooter();
+        log_break();
+        log_info("Program finished normally.\n");
+        return rc;
+    } catch (log_execution_error_exception) {
+        printFooter();
+        return -1;
+    }
+}
+
+void CommandHandler::load_json(Context *ctx, std::string filename)
+{
+    setupContext(ctx);
+    setupArchContext(ctx);
+    {
+        std::ifstream f(filename);
+        if (!parse_json(f, filename, ctx))
+            log_error("Loading design failed.\n");
+    }
+}
+
+void CommandHandler::clear() { vm.clear(); }
+
+void CommandHandler::run_script_hook(const std::string &name)
+{
+#ifndef NO_PYTHON
+    if (vm.count(name)) {
+        std::vector<std::string> files = vm[name].as<std::vector<std::string>>();
+        for (auto filename : files)
+            execute_python_file(filename.c_str());
+    }
+#endif
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/command.h b/common/kernel/command.h
new file mode 100644
index 00000000..6cce8c61
--- /dev/null
+++ b/common/kernel/command.h
@@ -0,0 +1,74 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Miodrag Milanovic <micko@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef COMMAND_H
+#define COMMAND_H
+
+#include <boost/program_options.hpp>
+#include <fstream>
+#include "log.h"
+#include "nextpnr.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+namespace po = boost::program_options;
+
+class CommandHandler
+{
+  public:
+    CommandHandler(int argc, char **argv);
+    virtual ~CommandHandler(){};
+
+    int exec();
+    void load_json(Context *ctx, std::string filename);
+    void clear();
+    void run_script_hook(const std::string &name);
+
+  protected:
+    virtual void setupArchContext(Context *ctx) = 0;
+    virtual std::unique_ptr<Context> createContext(dict<std::string, Property> &values) = 0;
+    virtual po::options_description getArchOptions() = 0;
+    virtual void validate(){};
+    virtual void customAfterLoad(Context *ctx){};
+    virtual void customBitstream(Context *ctx){};
+    void conflicting_options(const boost::program_options::variables_map &vm, const char *opt1, const char *opt2);
+
+  private:
+    bool parseOptions();
+    bool executeBeforeContext();
+    void setupContext(Context *ctx);
+    int executeMain(std::unique_ptr<Context> ctx);
+    po::options_description getGeneralOptions();
+    void printFooter();
+
+  protected:
+    po::variables_map vm;
+
+  private:
+    po::options_description options;
+    po::positional_options_description pos;
+    int argc;
+    char **argv;
+    std::ofstream logfile;
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif // COMMAND_H
diff --git a/common/kernel/constraints.h b/common/kernel/constraints.h
new file mode 100644
index 00000000..65abf12c
--- /dev/null
+++ b/common/kernel/constraints.h
@@ -0,0 +1,70 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2021  The SymbiFlow Authors.
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef CONSTRAINTS_H
+#define CONSTRAINTS_H
+
+#include <cstdint>
+#include <vector>
+
+#include "archdefs.h"
+#include "exclusive_state_groups.h"
+#include "hashlib.h"
+#include "idstring.h"
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct Context;
+
+template <std::size_t StateCount, typename StateType = int8_t, typename CountType = uint8_t> struct Constraints
+{
+    using ConstraintStateType = StateType;
+    using ConstraintCountType = CountType;
+
+    enum ConstraintType
+    {
+        CONSTRAINT_TAG_IMPLIES = 0,
+        CONSTRAINT_TAG_REQUIRES = 1,
+    };
+
+    template <typename StateRange> struct Constraint
+    {
+        virtual std::size_t tag() const = 0;
+        virtual ConstraintType constraint_type() const = 0;
+        virtual StateType state() const = 0;
+        virtual StateRange states() const = 0;
+    };
+
+    typedef ExclusiveStateGroup<StateCount, StateType, CountType> TagState;
+    dict<uint32_t, std::vector<typename TagState::Definition>> definitions;
+
+    template <typename ConstraintRange> void bindBel(TagState *tags, const ConstraintRange constraints);
+
+    template <typename ConstraintRange> void unbindBel(TagState *tags, const ConstraintRange constraints);
+
+    template <typename ConstraintRange>
+    bool isValidBelForCellType(const Context *ctx, uint32_t prototype, const TagState *tags,
+                               const ConstraintRange constraints, IdString object, IdString cell, BelId bel,
+                               bool explain_constraints) const;
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/constraints.impl.h b/common/kernel/constraints.impl.h
new file mode 100644
index 00000000..9c978411
--- /dev/null
+++ b/common/kernel/constraints.impl.h
@@ -0,0 +1,109 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2021  The SymbiFlow Authors.
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef CONSTRAINTS_IMPL_H
+#define CONSTRAINTS_IMPL_H
+
+#include "exclusive_state_groups.impl.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+template <size_t StateCount, typename StateType, typename CountType>
+template <typename ConstraintRange>
+void Constraints<StateCount, StateType, CountType>::bindBel(TagState *tags, const ConstraintRange constraints)
+{
+    for (const auto &constraint : constraints) {
+        switch (constraint.constraint_type()) {
+        case CONSTRAINT_TAG_IMPLIES:
+            tags[constraint.tag()].add_implies(constraint.state());
+            break;
+        case CONSTRAINT_TAG_REQUIRES:
+            break;
+        default:
+            NPNR_ASSERT(false);
+        }
+    }
+}
+
+template <size_t StateCount, typename StateType, typename CountType>
+template <typename ConstraintRange>
+void Constraints<StateCount, StateType, CountType>::unbindBel(TagState *tags, const ConstraintRange constraints)
+{
+    for (const auto &constraint : constraints) {
+        switch (constraint.constraint_type()) {
+        case CONSTRAINT_TAG_IMPLIES:
+            tags[constraint.tag()].remove_implies(constraint.state());
+            break;
+        case CONSTRAINT_TAG_REQUIRES:
+            break;
+        default:
+            NPNR_ASSERT(false);
+        }
+    }
+}
+
+template <size_t StateCount, typename StateType, typename CountType>
+template <typename ConstraintRange>
+bool Constraints<StateCount, StateType, CountType>::isValidBelForCellType(const Context *ctx, uint32_t prototype,
+                                                                          const TagState *tags,
+                                                                          const ConstraintRange constraints,
+                                                                          IdString object, IdString cell, BelId bel,
+                                                                          bool explain_constraints) const
+{
+    if (explain_constraints) {
+        auto &state_definition = definitions.at(prototype);
+        for (const auto &constraint : constraints) {
+            switch (constraint.constraint_type()) {
+            case CONSTRAINT_TAG_IMPLIES:
+                tags[constraint.tag()].explain_implies(ctx, object, cell, state_definition.at(constraint.tag()), bel,
+                                                       constraint.state());
+                break;
+            case CONSTRAINT_TAG_REQUIRES:
+                tags[constraint.tag()].explain_requires(ctx, object, cell, state_definition.at(constraint.tag()), bel,
+                                                        constraint.states());
+                break;
+            default:
+                NPNR_ASSERT(false);
+            }
+        }
+    }
+
+    for (const auto &constraint : constraints) {
+        switch (constraint.constraint_type()) {
+        case CONSTRAINT_TAG_IMPLIES:
+            if (!tags[constraint.tag()].check_implies(constraint.state())) {
+                return false;
+            }
+            break;
+        case CONSTRAINT_TAG_REQUIRES:
+            if (!tags[constraint.tag()].requires(constraint.states())) {
+                return false;
+            }
+            break;
+        default:
+            NPNR_ASSERT(false);
+        }
+    }
+
+    return true;
+}
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/context.cc b/common/kernel/context.cc
new file mode 100644
index 00000000..e35d3e49
--- /dev/null
+++ b/common/kernel/context.cc
@@ -0,0 +1,428 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "context.h"
+
+#include "log.h"
+#include "nextpnr_namespaces.h"
+#include "util.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+WireId Context::getNetinfoSourceWire(const NetInfo *net_info) const
+{
+    if (net_info->driver.cell == nullptr)
+        return WireId();
+
+    auto src_bel = net_info->driver.cell->bel;
+
+    if (src_bel == BelId())
+        return WireId();
+
+    auto bel_pins = getBelPinsForCellPin(net_info->driver.cell, net_info->driver.port);
+    auto iter = bel_pins.begin();
+    if (iter == bel_pins.end())
+        return WireId();
+    WireId driver = getBelPinWire(src_bel, *iter);
+    ++iter;
+    NPNR_ASSERT(iter == bel_pins.end()); // assert there is only one driver bel pin;
+    return driver;
+}
+
+SSOArray<WireId, 2> Context::getNetinfoSinkWires(const NetInfo *net_info, const PortRef &user_info) const
+{
+    auto dst_bel = user_info.cell->bel;
+    if (dst_bel == BelId())
+        return SSOArray<WireId, 2>(0, WireId());
+    size_t bel_pin_count = 0;
+    // We use an SSOArray here because it avoids any heap allocation for the 99.9% case of 1 or 2 sink wires
+    // but as SSOArray doesn't (currently) support resizing to keep things simple it does mean we have to do
+    // two loops
+    for (auto s : getBelPinsForCellPin(user_info.cell, user_info.port)) {
+        (void)s; // unused
+        ++bel_pin_count;
+    }
+    SSOArray<WireId, 2> result(bel_pin_count, WireId());
+    bel_pin_count = 0;
+    for (auto pin : getBelPinsForCellPin(user_info.cell, user_info.port)) {
+        result[bel_pin_count++] = getBelPinWire(dst_bel, pin);
+    }
+    return result;
+}
+
+size_t Context::getNetinfoSinkWireCount(const NetInfo *net_info, const PortRef &sink) const
+{
+    size_t count = 0;
+    for (auto s : getNetinfoSinkWires(net_info, sink)) {
+        (void)s; // unused
+        ++count;
+    }
+    return count;
+}
+
+WireId Context::getNetinfoSinkWire(const NetInfo *net_info, const PortRef &sink, size_t phys_idx) const
+{
+    size_t count = 0;
+    for (auto s : getNetinfoSinkWires(net_info, sink)) {
+        if (count == phys_idx)
+            return s;
+        ++count;
+    }
+    /* TODO: This should be an assertion failure, but for the zero-wire case of unplaced sinks; legacy code currently
+    assumes WireId Remove once the refactoring process is complete.
+    */
+    return WireId();
+}
+
+delay_t Context::predictArcDelay(const NetInfo *net_info, const PortRef &sink) const
+{
+    if (net_info->driver.cell == nullptr || net_info->driver.cell->bel == BelId() || sink.cell->bel == BelId())
+        return 0;
+    IdString driver_pin, sink_pin;
+    // Pick the first pin for a prediction; assume all will be similar enouhg
+    for (auto pin : getBelPinsForCellPin(net_info->driver.cell, net_info->driver.port)) {
+        driver_pin = pin;
+        break;
+    }
+    for (auto pin : getBelPinsForCellPin(sink.cell, sink.port)) {
+        sink_pin = pin;
+        break;
+    }
+    if (driver_pin == IdString() || sink_pin == IdString())
+        return 0;
+    return predictDelay(net_info->driver.cell->bel, driver_pin, sink.cell->bel, sink_pin);
+}
+
+delay_t Context::getNetinfoRouteDelay(const NetInfo *net_info, const PortRef &user_info) const
+{
+#ifdef ARCH_ECP5
+    if (net_info->is_global)
+        return 0;
+#endif
+
+    if (net_info->wires.empty())
+        return predictArcDelay(net_info, user_info);
+
+    WireId src_wire = getNetinfoSourceWire(net_info);
+    if (src_wire == WireId())
+        return 0;
+
+    delay_t max_delay = 0;
+
+    for (auto dst_wire : getNetinfoSinkWires(net_info, user_info)) {
+        WireId cursor = dst_wire;
+        delay_t delay = 0;
+
+        while (cursor != WireId() && cursor != src_wire) {
+            auto it = net_info->wires.find(cursor);
+
+            if (it == net_info->wires.end())
+                break;
+
+            PipId pip = it->second.pip;
+            if (pip == PipId())
+                break;
+
+            delay += getPipDelay(pip).maxDelay();
+            delay += getWireDelay(cursor).maxDelay();
+            cursor = getPipSrcWire(pip);
+        }
+
+        if (cursor == src_wire)
+            max_delay = std::max(max_delay, delay + getWireDelay(src_wire).maxDelay()); // routed
+        else
+            max_delay = std::max(max_delay, predictArcDelay(net_info, user_info)); // unrouted
+    }
+    return max_delay;
+}
+
+static uint32_t xorshift32(uint32_t x)
+{
+    x ^= x << 13;
+    x ^= x >> 17;
+    x ^= x << 5;
+    return x;
+}
+
+uint32_t Context::checksum() const
+{
+    uint32_t cksum = xorshift32(123456789);
+
+    uint32_t cksum_nets_sum = 0;
+    for (auto &it : nets) {
+        auto &ni = *it.second;
+        uint32_t x = 123456789;
+        x = xorshift32(x + xorshift32(it.first.index));
+        x = xorshift32(x + xorshift32(ni.name.index));
+        if (ni.driver.cell)
+            x = xorshift32(x + xorshift32(ni.driver.cell->name.index));
+        x = xorshift32(x + xorshift32(ni.driver.port.index));
+        x = xorshift32(x + xorshift32(getDelayChecksum(ni.driver.budget)));
+
+        for (auto &u : ni.users) {
+            if (u.cell)
+                x = xorshift32(x + xorshift32(u.cell->name.index));
+            x = xorshift32(x + xorshift32(u.port.index));
+            x = xorshift32(x + xorshift32(getDelayChecksum(u.budget)));
+        }
+
+        uint32_t attr_x_sum = 0;
+        for (auto &a : ni.attrs) {
+            uint32_t attr_x = 123456789;
+            attr_x = xorshift32(attr_x + xorshift32(a.first.index));
+            for (char ch : a.second.str)
+                attr_x = xorshift32(attr_x + xorshift32((int)ch));
+            attr_x_sum += attr_x;
+        }
+        x = xorshift32(x + xorshift32(attr_x_sum));
+
+        uint32_t wire_x_sum = 0;
+        for (auto &w : ni.wires) {
+            uint32_t wire_x = 123456789;
+            wire_x = xorshift32(wire_x + xorshift32(getWireChecksum(w.first)));
+            wire_x = xorshift32(wire_x + xorshift32(getPipChecksum(w.second.pip)));
+            wire_x = xorshift32(wire_x + xorshift32(int(w.second.strength)));
+            wire_x_sum += wire_x;
+        }
+        x = xorshift32(x + xorshift32(wire_x_sum));
+
+        cksum_nets_sum += x;
+    }
+    cksum = xorshift32(cksum + xorshift32(cksum_nets_sum));
+
+    uint32_t cksum_cells_sum = 0;
+    for (auto &it : cells) {
+        auto &ci = *it.second;
+        uint32_t x = 123456789;
+        x = xorshift32(x + xorshift32(it.first.index));
+        x = xorshift32(x + xorshift32(ci.name.index));
+        x = xorshift32(x + xorshift32(ci.type.index));
+
+        uint32_t port_x_sum = 0;
+        for (auto &p : ci.ports) {
+            uint32_t port_x = 123456789;
+            port_x = xorshift32(port_x + xorshift32(p.first.index));
+            port_x = xorshift32(port_x + xorshift32(p.second.name.index));
+            if (p.second.net)
+                port_x = xorshift32(port_x + xorshift32(p.second.net->name.index));
+            port_x = xorshift32(port_x + xorshift32(p.second.type));
+            port_x_sum += port_x;
+        }
+        x = xorshift32(x + xorshift32(port_x_sum));
+
+        uint32_t attr_x_sum = 0;
+        for (auto &a : ci.attrs) {
+            uint32_t attr_x = 123456789;
+            attr_x = xorshift32(attr_x + xorshift32(a.first.index));
+            for (char ch : a.second.str)
+                attr_x = xorshift32(attr_x + xorshift32((int)ch));
+            attr_x_sum += attr_x;
+        }
+        x = xorshift32(x + xorshift32(attr_x_sum));
+
+        uint32_t param_x_sum = 0;
+        for (auto &p : ci.params) {
+            uint32_t param_x = 123456789;
+            param_x = xorshift32(param_x + xorshift32(p.first.index));
+            for (char ch : p.second.str)
+                param_x = xorshift32(param_x + xorshift32((int)ch));
+            param_x_sum += param_x;
+        }
+        x = xorshift32(x + xorshift32(param_x_sum));
+
+        x = xorshift32(x + xorshift32(getBelChecksum(ci.bel)));
+        x = xorshift32(x + xorshift32(ci.belStrength));
+
+        cksum_cells_sum += x;
+    }
+    cksum = xorshift32(cksum + xorshift32(cksum_cells_sum));
+
+    return cksum;
+}
+
+void Context::check() const
+{
+    bool check_failed = false;
+
+#define CHECK_FAIL(...)                                                                                                \
+    do {                                                                                                               \
+        log_nonfatal_error(__VA_ARGS__);                                                                               \
+        check_failed = true;                                                                                           \
+    } while (false)
+
+    for (auto &n : nets) {
+        auto ni = n.second.get();
+        if (n.first != ni->name)
+            CHECK_FAIL("net key '%s' not equal to name '%s'\n", nameOf(n.first), nameOf(ni->name));
+        for (auto &w : ni->wires) {
+            if (ni != getBoundWireNet(w.first))
+                CHECK_FAIL("net '%s' not bound to wire '%s' in wires map\n", nameOf(n.first), nameOfWire(w.first));
+            if (w.second.pip != PipId()) {
+                if (w.first != getPipDstWire(w.second.pip))
+                    CHECK_FAIL("net '%s' has dest mismatch '%s' vs '%s' in for pip '%s'\n", nameOf(n.first),
+                               nameOfWire(w.first), nameOfWire(getPipDstWire(w.second.pip)), nameOfPip(w.second.pip));
+                if (ni != getBoundPipNet(w.second.pip))
+                    CHECK_FAIL("net '%s' not bound to pip '%s' in wires map\n", nameOf(n.first),
+                               nameOfPip(w.second.pip));
+            }
+        }
+        if (ni->driver.cell != nullptr) {
+            if (!ni->driver.cell->ports.count(ni->driver.port)) {
+                CHECK_FAIL("net '%s' driver port '%s' missing on cell '%s'\n", nameOf(n.first), nameOf(ni->driver.port),
+                           nameOf(ni->driver.cell));
+            } else {
+                const NetInfo *p_net = ni->driver.cell->ports.at(ni->driver.port).net;
+                if (p_net != ni)
+                    CHECK_FAIL("net '%s' driver port '%s.%s' connected to incorrect net '%s'\n", nameOf(n.first),
+                               nameOf(ni->driver.cell), nameOf(ni->driver.port), p_net ? nameOf(p_net) : "<nullptr>");
+            }
+        }
+        for (auto user : ni->users) {
+            if (!user.cell->ports.count(user.port)) {
+                CHECK_FAIL("net '%s' user port '%s' missing on cell '%s'\n", nameOf(n.first), nameOf(user.port),
+                           nameOf(user.cell));
+            } else {
+                const NetInfo *p_net = user.cell->ports.at(user.port).net;
+                if (p_net != ni)
+                    CHECK_FAIL("net '%s' user port '%s.%s' connected to incorrect net '%s'\n", nameOf(n.first),
+                               nameOf(user.cell), nameOf(user.port), p_net ? nameOf(p_net) : "<nullptr>");
+            }
+        }
+    }
+#ifdef CHECK_WIRES
+    for (auto w : getWires()) {
+        auto ni = getBoundWireNet(w);
+        if (ni != nullptr) {
+            if (!ni->wires.count(w))
+                CHECK_FAIL("wire '%s' missing in wires map of bound net '%s'\n", nameOfWire(w), nameOf(ni));
+        }
+    }
+#endif
+    for (auto &c : cells) {
+        auto ci = c.second.get();
+        if (c.first != ci->name)
+            CHECK_FAIL("cell key '%s' not equal to name '%s'\n", nameOf(c.first), nameOf(ci->name));
+        if (ci->bel != BelId()) {
+            if (getBoundBelCell(c.second->bel) != ci)
+                CHECK_FAIL("cell '%s' not bound to bel '%s' in bel field\n", nameOf(c.first), nameOfBel(ci->bel));
+        }
+        for (auto &port : c.second->ports) {
+            NetInfo *net = port.second.net;
+            if (net != nullptr) {
+                if (nets.find(net->name) == nets.end()) {
+                    CHECK_FAIL("cell port '%s.%s' connected to non-existent net '%s'\n", nameOf(c.first),
+                               nameOf(port.first), nameOf(net->name));
+                } else if (port.second.type == PORT_OUT) {
+                    if (net->driver.cell != c.second.get() || net->driver.port != port.first) {
+                        CHECK_FAIL("output cell port '%s.%s' not in driver field of net '%s'\n", nameOf(c.first),
+                                   nameOf(port.first), nameOf(net));
+                    }
+                } else if (port.second.type == PORT_IN) {
+                    if (!port.second.user_idx)
+                        CHECK_FAIL("input cell port '%s.%s' on net '%s' has no user index\n", nameOf(c.first),
+                                   nameOf(port.first), nameOf(net));
+                    auto net_user = net->users.at(port.second.user_idx);
+                    if (net_user.cell != c.second.get() || net_user.port != port.first)
+                        CHECK_FAIL("input cell port '%s.%s' not in associated user entry of net '%s'\n",
+                                   nameOf(c.first), nameOf(port.first), nameOf(net));
+                }
+            }
+        }
+    }
+
+#undef CHECK_FAIL
+
+    if (check_failed)
+        log_error("INTERNAL CHECK FAILED: please report this error with the design and full log output. Failure "
+                  "details are above this message.\n");
+}
+
+namespace {
+struct FixupHierarchyWorker
+{
+    FixupHierarchyWorker(Context *ctx) : ctx(ctx){};
+    Context *ctx;
+    void run()
+    {
+        trim_hierarchy(ctx->top_module);
+        rebuild_hierarchy();
+    };
+    // Remove cells and nets that no longer exist in the netlist
+    std::vector<IdString> todelete_cells, todelete_nets;
+    void trim_hierarchy(IdString path)
+    {
+        auto &h = ctx->hierarchy.at(path);
+        todelete_cells.clear();
+        todelete_nets.clear();
+        for (auto &lc : h.leaf_cells) {
+            if (!ctx->cells.count(lc.second))
+                todelete_cells.push_back(lc.first);
+        }
+        for (auto &n : h.nets)
+            if (!ctx->nets.count(n.second))
+                todelete_nets.push_back(n.first);
+        for (auto tdc : todelete_cells) {
+            h.leaf_cells_by_gname.erase(h.leaf_cells.at(tdc));
+            h.leaf_cells.erase(tdc);
+        }
+        for (auto tdn : todelete_nets) {
+            h.nets_by_gname.erase(h.nets.at(tdn));
+            h.nets.erase(tdn);
+        }
+        for (auto &sc : h.hier_cells)
+            trim_hierarchy(sc.second);
+    }
+
+    IdString construct_local_name(HierarchicalCell &hc, IdString global_name, bool is_cell)
+    {
+        std::string gn = global_name.str(ctx);
+        auto dp = gn.find_last_of('.');
+        if (dp != std::string::npos)
+            gn = gn.substr(dp + 1);
+        IdString name = ctx->id(gn);
+        // Make sure name is unique
+        int adder = 0;
+        while (is_cell ? hc.leaf_cells.count(name) : hc.nets.count(name)) {
+            ++adder;
+            name = ctx->id(gn + "$" + std::to_string(adder));
+        }
+        return name;
+    }
+
+    // Update hierarchy structure for nets and cells that have hiercell set
+    void rebuild_hierarchy()
+    {
+        for (auto &cell : ctx->cells) {
+            CellInfo *ci = cell.second.get();
+            if (ci->hierpath == IdString())
+                ci->hierpath = ctx->top_module;
+            auto &hc = ctx->hierarchy.at(ci->hierpath);
+            if (hc.leaf_cells_by_gname.count(ci->name))
+                continue; // already known
+            IdString local_name = construct_local_name(hc, ci->name, true);
+            hc.leaf_cells_by_gname[ci->name] = local_name;
+            hc.leaf_cells[local_name] = ci->name;
+        }
+    }
+};
+} // namespace
+
+void Context::fixupHierarchy() { FixupHierarchyWorker(this).run(); }
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/context.h b/common/kernel/context.h
new file mode 100644
index 00000000..cb8fd257
--- /dev/null
+++ b/common/kernel/context.h
@@ -0,0 +1,119 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef CONTEXT_H
+#define CONTEXT_H
+
+#include <boost/lexical_cast.hpp>
+
+#include "arch.h"
+#include "deterministic_rng.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct Context : Arch, DeterministicRNG
+{
+    bool verbose = false;
+    bool debug = false;
+    bool force = false;
+
+    // Should we disable printing of the location of nets in the critical path?
+    bool disable_critical_path_source_print = false;
+    // True when detailed per-net timing is to be stored / reported
+    bool detailed_timing_report = false;
+
+    ArchArgs arch_args;
+
+    Context(ArchArgs args) : Arch(args)
+    {
+        BaseCtx::as_ctx = this;
+        arch_args = args;
+    }
+
+    ArchArgs getArchArgs() { return arch_args; }
+
+    // --------------------------------------------------------------
+
+    delay_t predictArcDelay(const NetInfo *net_info, const PortRef &sink) const;
+
+    WireId getNetinfoSourceWire(const NetInfo *net_info) const;
+    SSOArray<WireId, 2> getNetinfoSinkWires(const NetInfo *net_info, const PortRef &sink) const;
+    size_t getNetinfoSinkWireCount(const NetInfo *net_info, const PortRef &sink) const;
+    WireId getNetinfoSinkWire(const NetInfo *net_info, const PortRef &sink, size_t phys_idx) const;
+    delay_t getNetinfoRouteDelay(const NetInfo *net_info, const PortRef &sink) const;
+
+    // provided by router1.cc
+    bool checkRoutedDesign() const;
+    bool getActualRouteDelay(WireId src_wire, WireId dst_wire, delay_t *delay = nullptr,
+                             dict<WireId, PipId> *route = nullptr, bool useEstimate = true);
+
+    // --------------------------------------------------------------
+    // call after changing hierpath or adding/removing nets and cells
+    void fixupHierarchy();
+
+    // --------------------------------------------------------------
+
+    // provided by sdf.cc
+    void writeSDF(std::ostream &out, bool cvc_mode = false) const;
+
+    // --------------------------------------------------------------
+
+    // provided by svg.cc
+    void writeSVG(const std::string &filename, const std::string &flags = "") const;
+
+    // --------------------------------------------------------------
+
+    // provided by report.cc
+    void writeReport(std::ostream &out) const;
+    // --------------------------------------------------------------
+
+    uint32_t checksum() const;
+
+    void check() const;
+    void archcheck() const;
+
+    template <typename T> T setting(const char *name, T defaultValue)
+    {
+        IdString new_id = id(name);
+        auto found = settings.find(new_id);
+        if (found != settings.end())
+            return boost::lexical_cast<T>(found->second.is_string ? found->second.as_string()
+                                                                  : std::to_string(found->second.as_int64()));
+        else
+            settings[id(name)] = std::to_string(defaultValue);
+
+        return defaultValue;
+    }
+
+    template <typename T> T setting(const char *name) const
+    {
+        IdString new_id = id(name);
+        auto found = settings.find(new_id);
+        if (found != settings.end())
+            return boost::lexical_cast<T>(found->second.is_string ? found->second.as_string()
+                                                                  : std::to_string(found->second.as_int64()));
+        else
+            throw std::runtime_error("settings does not exists");
+    }
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* CONTEXT_H */
diff --git a/common/kernel/design_utils.cc b/common/kernel/design_utils.cc
new file mode 100644
index 00000000..f52cc304
--- /dev/null
+++ b/common/kernel/design_utils.cc
@@ -0,0 +1,52 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "design_utils.h"
+#include <algorithm>
+#include <map>
+#include "log.h"
+#include "util.h"
+NEXTPNR_NAMESPACE_BEGIN
+
+// Print utilisation of a design
+void print_utilisation(const Context *ctx)
+{
+    // Sort by Bel type
+    std::map<IdString, int> used_types;
+    for (auto &cell : ctx->cells) {
+        used_types[ctx->getBelBucketName(ctx->getBelBucketForCellType(cell.second.get()->type))]++;
+    }
+    std::map<IdString, int> available_types;
+    for (auto bel : ctx->getBels()) {
+        if (!ctx->getBelHidden(bel)) {
+            available_types[ctx->getBelBucketName(ctx->getBelBucketForBel(bel))]++;
+        }
+    }
+    log_break();
+    log_info("Device utilisation:\n");
+    for (auto type : available_types) {
+        IdString type_id = type.first;
+        int used_bels = get_or_default(used_types, type.first, 0);
+        log_info("\t%20s: %5d/%5d %5d%%\n", type_id.c_str(ctx), used_bels, type.second, 100 * used_bels / type.second);
+    }
+    log_break();
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/design_utils.h b/common/kernel/design_utils.h
new file mode 100644
index 00000000..069600b5
--- /dev/null
+++ b/common/kernel/design_utils.h
@@ -0,0 +1,100 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "nextpnr.h"
+
+#ifndef DESIGN_UTILS_H
+#define DESIGN_UTILS_H
+
+#include <algorithm>
+
+NEXTPNR_NAMESPACE_BEGIN
+
+/*
+Utilities for design manipulation, intended for use inside packing algorithms
+ */
+
+// Disconnect a net (if connected) from old, and connect it to rep
+void replace_port(CellInfo *old_cell, IdString old_name, CellInfo *rep_cell, IdString rep_name);
+
+// If a net drives a given port of a cell matching a predicate (in many
+// cases more than one cell type, e.g. SB_DFFxx so a predicate is used), return
+// the first instance of that cell (otherwise nullptr). If exclusive is set to
+// true, then this cell must be the only load. If ignore_cell is set, that cell
+// is not considered
+template <typename F1>
+CellInfo *net_only_drives(const Context *ctx, NetInfo *net, F1 cell_pred, IdString port, bool exclusive = false,
+                          CellInfo *exclude = nullptr)
+{
+    if (net == nullptr)
+        return nullptr;
+    if (exclusive) {
+        if (exclude == nullptr) {
+            if (net->users.entries() != 1)
+                return nullptr;
+        } else {
+            if (net->users.entries() > 2) {
+                return nullptr;
+            } else if (net->users.entries() == 2) {
+                bool found = false;
+                for (auto &usr : net->users) {
+                    if (usr.cell == exclude)
+                        found = true;
+                }
+                if (!found)
+                    return nullptr;
+            }
+        }
+    }
+    for (const auto &load : net->users) {
+        if (load.cell != exclude && cell_pred(ctx, load.cell) && load.port == port) {
+            return load.cell;
+        }
+    }
+    return nullptr;
+}
+
+// If a net is driven by a given port of a cell matching a predicate, return
+// that cell, otherwise nullptr
+template <typename F1> CellInfo *net_driven_by(const Context *ctx, const NetInfo *net, F1 cell_pred, IdString port)
+{
+    if (net == nullptr)
+        return nullptr;
+    if (net->driver.cell == nullptr)
+        return nullptr;
+    if (cell_pred(ctx, net->driver.cell) && net->driver.port == port) {
+        return net->driver.cell;
+    } else {
+        return nullptr;
+    }
+}
+
+// Check if a port is used
+inline bool port_used(CellInfo *cell, IdString port_name)
+{
+    auto port_fnd = cell->ports.find(port_name);
+    return port_fnd != cell->ports.end() && port_fnd->second.net != nullptr;
+}
+
+void print_utilisation(const Context *ctx);
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/deterministic_rng.h b/common/kernel/deterministic_rng.h
new file mode 100644
index 00000000..3aab5a49
--- /dev/null
+++ b/common/kernel/deterministic_rng.h
@@ -0,0 +1,103 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef DETERMINISTIC_RNG_H
+#define DETERMINISTIC_RNG_H
+
+#include <algorithm>
+#include <cassert>
+#include <cstdint>
+#include <vector>
+
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct DeterministicRNG
+{
+    uint64_t rngstate;
+
+    DeterministicRNG() : rngstate(0x3141592653589793) {}
+
+    uint64_t rng64()
+    {
+        // xorshift64star
+        // https://arxiv.org/abs/1402.6246
+
+        uint64_t retval = rngstate * 0x2545F4914F6CDD1D;
+
+        rngstate ^= rngstate >> 12;
+        rngstate ^= rngstate << 25;
+        rngstate ^= rngstate >> 27;
+
+        return retval;
+    }
+
+    int rng() { return rng64() & 0x3fffffff; }
+
+    int rng(int n)
+    {
+        assert(n > 0);
+
+        // round up to power of 2
+        int m = n - 1;
+        m |= (m >> 1);
+        m |= (m >> 2);
+        m |= (m >> 4);
+        m |= (m >> 8);
+        m |= (m >> 16);
+        m += 1;
+
+        while (1) {
+            int x = rng64() & (m - 1);
+            if (x < n)
+                return x;
+        }
+    }
+
+    void rngseed(uint64_t seed)
+    {
+        rngstate = seed ? seed : 0x3141592653589793;
+        for (int i = 0; i < 5; i++)
+            rng64();
+    }
+
+    template <typename Iter> void shuffle(const Iter &begin, const Iter &end)
+    {
+        std::size_t size = end - begin;
+        for (std::size_t i = 0; i != size; i++) {
+            std::size_t j = i + rng(size - i);
+            if (j > i)
+                std::swap(*(begin + i), *(begin + j));
+        }
+    }
+
+    template <typename T> void shuffle(std::vector<T> &a) { shuffle(a.begin(), a.end()); }
+
+    template <typename T> void sorted_shuffle(std::vector<T> &a)
+    {
+        std::sort(a.begin(), a.end());
+        shuffle(a);
+    }
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/dynamic_bitarray.h b/common/kernel/dynamic_bitarray.h
new file mode 100644
index 00000000..be41835b
--- /dev/null
+++ b/common/kernel/dynamic_bitarray.h
@@ -0,0 +1,211 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2021  Symbiflow Authors
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef DYNAMIC_BITARRAY_H
+#define DYNAMIC_BITARRAY_H
+
+#include <cstdint>
+#include <limits>
+#include <vector>
+
+#include "log.h"
+#include "nextpnr_assertions.h"
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+// This class implements a simple dynamic bitarray, backed by some resizable
+// random access storage.  The default is to use a std::vector<uint8_t>.
+template <typename Storage = std::vector<uint8_t>> class DynamicBitarray
+{
+  public:
+    static_assert(!std::numeric_limits<typename Storage::value_type>::is_signed, "Storage must be unsigned!");
+
+    void fill(bool value)
+    {
+        std::fill(storage.begin(), storage.end(), value ? std::numeric_limits<typename Storage::value_type>::max() : 0);
+    }
+
+    constexpr size_t bits_per_value() const { return std::numeric_limits<typename Storage::value_type>::digits; }
+
+    bool get(size_t bit) const
+    {
+        size_t element_index = bit / bits_per_value();
+        size_t bit_offset = bit % bits_per_value();
+
+        auto element = storage.at(element_index);
+        return (element & (1 << bit_offset)) != 0;
+    }
+
+    void set(size_t bit, bool value)
+    {
+        size_t element_index = bit / bits_per_value();
+        size_t bit_offset = bit % bits_per_value();
+
+        if (value) {
+            storage.at(element_index) |= (1 << bit_offset);
+        } else {
+            storage.at(element_index) &= ~(1 << bit_offset);
+        }
+    }
+
+    void resize(size_t number_bits)
+    {
+        size_t required_storage = (number_bits + bits_per_value() - 1) / bits_per_value();
+        storage.resize(required_storage);
+    }
+
+    size_t size() const { return storage.size() * bits_per_value(); }
+
+    void clear() { return storage.clear(); }
+
+    // Convert IntType to a DynamicBitarray of sufficent width
+    template <typename IntType> static DynamicBitarray<Storage> to_bitarray(const IntType &value)
+    {
+        if (std::numeric_limits<IntType>::is_signed) {
+            if (value < 0) {
+                log_error("Expected position value, got %s\n", std::to_string(value).c_str());
+            }
+        }
+
+        DynamicBitarray<Storage> result;
+        result.resize(std::numeric_limits<IntType>::digits);
+        result.fill(false);
+
+        // Use a 1 of the right type (for shifting)
+        IntType one(1);
+
+        for (size_t i = 0; i < std::numeric_limits<IntType>::digits; ++i) {
+            if ((value & (one << i)) != 0) {
+                result.set(i, true);
+            }
+        }
+
+        return result;
+    }
+
+    // Convert binary bitstring to a DynamicBitarray of sufficent width
+    //
+    // string must be satisfy the following regex:
+    //
+    //    [01]+
+    //
+    // width can either be specified explicitly, or -1 to use a size wide
+    // enough to store the given string.
+    //
+    // If the width is specified and the width is insufficent it will result
+    // in an error.
+    static DynamicBitarray<Storage> parse_binary_bitstring(int width, const std::string &bits)
+    {
+        NPNR_ASSERT(width == -1 || width > 0);
+
+        DynamicBitarray<Storage> result;
+        // If no width was supplied, use the width from the input data.
+        if (width == -1) {
+            width = bits.size();
+        }
+
+        NPNR_ASSERT(width >= 0);
+        if ((size_t)width < bits.size()) {
+            log_error("String '%s' is wider than specified width %d\n", bits.c_str(), width);
+        }
+        result.resize(width);
+        result.fill(false);
+
+        for (size_t i = 0; i < bits.size(); ++i) {
+            // bits[0] is the MSB!
+            size_t index = width - 1 - i;
+            if (!(bits[i] == '1' || bits[i] == '0')) {
+                log_error("String '%s' is not a valid binary bitstring?\n", bits.c_str());
+            }
+            result.set(index, bits[i] == '1');
+        }
+
+        return result;
+    }
+
+    // Convert hex bitstring to a DynamicBitarray of sufficent width
+    //
+    // string must be satisfy the following regex:
+    //
+    //    [0-9a-fA-F]+
+    //
+    // width can either be specified explicitly, or -1 to use a size wide
+    // enough to store the given string.
+    //
+    // If the width is specified and the width is insufficent it will result
+    // in an error.
+    static DynamicBitarray<Storage> parse_hex_bitstring(int width, const std::string &bits)
+    {
+        NPNR_ASSERT(width == -1 || width > 0);
+
+        DynamicBitarray<Storage> result;
+        // If no width was supplied, use the width from the input data.
+        if (width == -1) {
+            // Each character is 4 bits!
+            width = bits.size() * 4;
+        }
+
+        NPNR_ASSERT(width >= 0);
+        int rem = width % 4;
+        size_t check_width = width;
+        if (rem != 0) {
+            check_width += (4 - rem);
+        }
+        if (check_width < bits.size() * 4) {
+            log_error("String '%s' is wider than specified width %d (check_width = %zu)\n", bits.c_str(), width,
+                      check_width);
+        }
+
+        result.resize(width);
+        result.fill(false);
+
+        size_t index = 0;
+        for (auto nibble_iter = bits.rbegin(); nibble_iter != bits.rend(); ++nibble_iter) {
+            char nibble = *nibble_iter;
+
+            int value;
+            if (nibble >= '0' && nibble <= '9') {
+                value = nibble - '0';
+            } else if (nibble >= 'a' && nibble <= 'f') {
+                value = 10 + (nibble - 'a');
+            } else if (nibble >= 'A' && nibble <= 'F') {
+                value = 10 + (nibble - 'A');
+            } else {
+                log_error("Invalid hex string '%s'?\n", bits.c_str());
+            }
+            NPNR_ASSERT(value >= 0);
+            NPNR_ASSERT(value < 16);
+
+            // Insert nibble into bitarray.
+            for (size_t i = 0; i < 4; ++i) {
+                result.set(index++, (value & (1 << i)) != 0);
+            }
+        }
+
+        return result;
+    }
+
+  private:
+    Storage storage;
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* DYNAMIC_BITARRAY_H */
diff --git a/common/kernel/embed.cc b/common/kernel/embed.cc
new file mode 100644
index 00000000..70bbc6fb
--- /dev/null
+++ b/common/kernel/embed.cc
@@ -0,0 +1,49 @@
+#if defined(WIN32)
+#include <windows.h>
+#endif
+#include <boost/filesystem.hpp>
+#include <boost/iostreams/device/mapped_file.hpp>
+#include "embed.h"
+#include "nextpnr.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+#if defined(EXTERNAL_CHIPDB_ROOT)
+
+const void *get_chipdb(const std::string &filename)
+{
+    static std::map<std::string, boost::iostreams::mapped_file> files;
+    if (!files.count(filename)) {
+        std::string full_filename = EXTERNAL_CHIPDB_ROOT "/" + filename;
+        if (boost::filesystem::exists(full_filename))
+            files[filename].open(full_filename, boost::iostreams::mapped_file::priv);
+    }
+    if (files.count(filename))
+        return files.at(filename).data();
+    return nullptr;
+}
+
+#elif defined(WIN32)
+
+const void *get_chipdb(const std::string &filename)
+{
+    HRSRC rc = ::FindResource(nullptr, filename.c_str(), RT_RCDATA);
+    HGLOBAL rcData = ::LoadResource(nullptr, rc);
+    return ::LockResource(rcData);
+}
+
+#else
+
+EmbeddedFile *EmbeddedFile::head = nullptr;
+
+const void *get_chipdb(const std::string &filename)
+{
+    for (EmbeddedFile *file = EmbeddedFile::head; file; file = file->next)
+        if (file->filename == filename)
+            return file->content;
+    return nullptr;
+}
+
+#endif
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/embed.h b/common/kernel/embed.h
new file mode 100644
index 00000000..5f2754f8
--- /dev/null
+++ b/common/kernel/embed.h
@@ -0,0 +1,49 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2020  whitequark <whitequark@whitequark.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef EMBED_H
+#define EMBED_H
+
+#include "nextpnr.h"
+NEXTPNR_NAMESPACE_BEGIN
+
+#if !defined(EXTERNAL_CHIPDB_ROOT) && !defined(WIN32)
+
+struct EmbeddedFile
+{
+    static EmbeddedFile *head;
+
+    std::string filename;
+    const void *content;
+    EmbeddedFile *next = nullptr;
+
+    EmbeddedFile(const std::string &filename, const void *content) : filename(filename), content(content)
+    {
+        next = head;
+        head = this;
+    }
+};
+
+#endif
+
+const void *get_chipdb(const std::string &filename);
+
+NEXTPNR_NAMESPACE_END
+
+#endif // EMBED_H
diff --git a/common/kernel/exclusive_state_groups.h b/common/kernel/exclusive_state_groups.h
new file mode 100644
index 00000000..68ce7c4e
--- /dev/null
+++ b/common/kernel/exclusive_state_groups.h
@@ -0,0 +1,154 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2021  The SymbiFlow Authors.
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef EXCLUSIVE_STATE_GROUPS_H
+#define EXCLUSIVE_STATE_GROUPS_H
+
+#include <array>
+#include <bitset>
+#include <cstdint>
+#include <limits>
+#include <vector>
+
+#include "archdefs.h"
+#include "bits.h"
+#include "idstring.h"
+#include "nextpnr_assertions.h"
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+// Implementation for exclusive state groups, used to implement generic
+// constraint system.
+template <size_t StateCount, typename StateType = int8_t, typename CountType = uint8_t> struct ExclusiveStateGroup
+{
+    ExclusiveStateGroup() : state(kNoSelected) { count.fill(0); }
+    struct Definition
+    {
+        IdString prefix;
+        IdString default_state;
+        std::vector<IdString> states;
+    };
+
+    static_assert(StateCount < std::numeric_limits<StateType>::max(), "StateType cannot store max StateType");
+    static_assert(std::numeric_limits<StateType>::is_signed, "StateType must be signed");
+
+    std::bitset<StateCount> selected_states;
+    StateType state;
+    std::array<CountType, StateCount> count;
+
+    static constexpr StateType kNoSelected = -1;
+    static constexpr StateType kOverConstrained = -2;
+
+    std::pair<bool, IdString> current_state(const Definition &definition) const
+    {
+        if (state <= 0) {
+            return std::make_pair(state == kNoSelected, definition.default_state);
+        } else {
+            NPNR_ASSERT(state <= definition.states.size());
+            return std::make_pair(true, definition.states[state]);
+        }
+    }
+
+    bool check_implies(int32_t next_state) const
+    {
+        // Implies can be satified if either that state is
+        // selected, or no state is currently selected.
+        return state == next_state || state == kNoSelected;
+    }
+
+    bool add_implies(int32_t next_state)
+    {
+        NPNR_ASSERT(next_state >= 0 && (size_t)next_state < StateCount);
+
+        // Increment and mark the state as selected.
+        count[next_state] += 1;
+        selected_states[next_state] = true;
+
+        if (state == next_state) {
+            // State was already selected, state group is still satified.
+            return true;
+        } else if (selected_states.count() == 1) {
+            // State was not select selected, state is now selected.
+            // State group is satified.
+            state = next_state;
+            return true;
+        } else {
+            // State group is now overconstrained.
+            state = kOverConstrained;
+            return false;
+        }
+    };
+
+    void remove_implies(int32_t next_state)
+    {
+        NPNR_ASSERT(next_state >= 0 && (size_t)next_state < StateCount);
+        NPNR_ASSERT(selected_states[next_state]);
+
+        count[next_state] -= 1;
+        NPNR_ASSERT(count[next_state] >= 0);
+
+        // Check if next_state is now unselected.
+        if (count[next_state] == 0) {
+            // next_state is not longer selected
+            selected_states[next_state] = false;
+
+            // Check whether the state group is now unselected or satified.
+            auto value = selected_states.to_ulong();
+            auto number_selected = Bits::popcount(value);
+            if (number_selected == 1) {
+                // Group is no longer overconstrained.
+                state = Bits::ctz(value);
+                NPNR_ASSERT(selected_states[state]);
+            } else if (number_selected == 0) {
+                // Group is unselected.
+                state = kNoSelected;
+            } else {
+                state = kOverConstrained;
+            }
+        }
+    }
+
+    template <typename StateRange> bool requires(const StateRange &state_range) const
+    {
+        if (state < 0) {
+            return false;
+        }
+
+        for (const auto required_state : state_range) {
+            if (state == required_state) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    void print_debug(const Context *ctx, IdString object, const Definition &definition) const;
+    void explain_implies(const Context *ctx, IdString object, IdString cell, const Definition &definition, BelId bel,
+                         int32_t next_state) const;
+
+    template <typename StateRange>
+    void explain_requires(const Context *ctx, IdString object, IdString cell, const Definition &definition, BelId bel,
+                          const StateRange state_range) const;
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/exclusive_state_groups.impl.h b/common/kernel/exclusive_state_groups.impl.h
new file mode 100644
index 00000000..f3ddb5fd
--- /dev/null
+++ b/common/kernel/exclusive_state_groups.impl.h
@@ -0,0 +1,89 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2021  The SymbiFlow Authors.
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#pragma once
+
+#include "context.h"
+#include "exclusive_state_groups.h"
+#include "log.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+template <size_t StateCount, typename StateType, typename CountType>
+void ExclusiveStateGroup<StateCount, StateType, CountType>::print_debug(const Context *ctx, IdString object,
+                                                                        const Definition &definition) const
+{
+    if (state == kNoSelected) {
+        NPNR_ASSERT(selected_states.count() == 0);
+        log_info("%s.%s is currently unselected\n", object.c_str(ctx), definition.prefix.c_str(ctx));
+    } else if (state >= 0) {
+        log_info("%s.%s = %s, count = %d\n", object.c_str(ctx), definition.prefix.c_str(ctx),
+                 definition.states.at(state).c_str(ctx), count[state]);
+    } else {
+        NPNR_ASSERT(state == kOverConstrained);
+        log_info("%s.%s is currently overconstrained, states selected:\n", object.c_str(ctx),
+                 definition.prefix.c_str(ctx));
+        for (size_t i = 0; i < definition.states.size(); ++i) {
+            if (selected_states[i]) {
+                log_info(" - %s, count = %d\n", definition.states.at(i).c_str(ctx), count[i]);
+            }
+        }
+    }
+}
+
+template <size_t StateCount, typename StateType, typename CountType>
+void ExclusiveStateGroup<StateCount, StateType, CountType>::explain_implies(const Context *ctx, IdString object,
+                                                                            IdString cell, const Definition &definition,
+                                                                            BelId bel, int32_t next_state) const
+{
+    if (check_implies(next_state)) {
+        log_info("Placing cell %s at bel %s does not violate %s.%s\n", cell.c_str(ctx), ctx->nameOfBel(bel),
+                 object.c_str(ctx), definition.prefix.c_str(ctx));
+    } else {
+        log_info("Placing cell %s at bel %s does violates %s.%s, desired state = %s.\n", cell.c_str(ctx),
+                 ctx->nameOfBel(bel), object.c_str(ctx), definition.prefix.c_str(ctx),
+                 definition.states.at(next_state).c_str(ctx));
+        print_debug(ctx, object, definition);
+    }
+}
+
+template <size_t StateCount, typename StateType, typename CountType>
+template <typename StateRange>
+void ExclusiveStateGroup<StateCount, StateType, CountType>::explain_requires(const Context *ctx, IdString object,
+                                                                             IdString cell,
+                                                                             const Definition &definition, BelId bel,
+                                                                             const StateRange state_range) const
+{
+    if (requires(state_range)) {
+        log_info("Placing cell %s at bel %s does not violate %s.%s\n", cell.c_str(ctx), ctx->nameOfBel(bel),
+                 object.c_str(ctx), definition.prefix.c_str(ctx));
+    } else {
+        log_info("Placing cell %s at bel %s does violate %s.%s, because current state is %s, constraint requires one "
+                 "of:\n",
+                 cell.c_str(ctx), ctx->nameOfBel(bel), object.c_str(ctx), definition.prefix.c_str(ctx),
+                 state != -1 ? definition.states.at(state).c_str(ctx) : "unset");
+
+        for (const auto required_state : state_range) {
+            log_info(" - %s\n", definition.states.at(required_state).c_str(ctx));
+        }
+        print_debug(ctx, object, definition);
+    }
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/handle_error.cc b/common/kernel/handle_error.cc
new file mode 100644
index 00000000..d5542369
--- /dev/null
+++ b/common/kernel/handle_error.cc
@@ -0,0 +1,61 @@
+#ifndef NO_PYTHON
+
+#include <Python.h>
+#include <pybind11/pybind11.h>
+#include "nextpnr.h"
+
+namespace py = pybind11;
+
+NEXTPNR_NAMESPACE_BEGIN
+
+// Parses the value of the active python exception
+// NOTE SHOULD NOT BE CALLED IF NO EXCEPTION
+std::string parse_python_exception()
+{
+    PyObject *type_ptr = NULL, *value_ptr = NULL, *traceback_ptr = NULL;
+    // Fetch the exception info from the Python C API
+    PyErr_Fetch(&type_ptr, &value_ptr, &traceback_ptr);
+
+    // Fallback error
+    std::string ret("Unfetchable Python error");
+    // If the fetch got a type pointer, parse the type into the exception string
+    if (type_ptr != NULL) {
+        py::object obj = py::reinterpret_borrow<py::object>(type_ptr);
+        // If a valid string extraction is available, use it
+        //  otherwise use fallback
+        if (py::isinstance<py::str>(obj))
+            ret = obj.cast<std::string>();
+        else
+            ret = "Unknown exception type";
+    }
+    // Do the same for the exception value (the stringification of the
+    // exception)
+    if (value_ptr != NULL) {
+        py::object obj = py::reinterpret_borrow<py::object>(value_ptr);
+        if (py::isinstance<py::str>(obj))
+            ret += ": " + obj.cast<std::string>();
+        else
+            ret += std::string(": Unparseable Python error: ");
+    }
+    // Parse lines from the traceback using the Python traceback module
+    if (traceback_ptr != NULL) {
+        py::handle h_tb(traceback_ptr);
+        // Load the traceback module and the format_tb function
+        py::object tb(py::module::import("traceback"));
+        py::object fmt_tb(tb.attr("format_tb"));
+        // Call format_tb to get a list of traceback strings
+        py::object tb_list(fmt_tb(h_tb));
+        // Join the traceback strings into a single string
+        py::object tb_str(py::str("\n") + tb_list);
+        // Extract the string, check the extraction, and fallback in necessary
+        if (py::isinstance<py::str>(tb_str))
+            ret += ": " + tb_str.cast<std::string>();
+        else
+            ret += std::string(": Unparseable Python traceback");
+    }
+    return ret;
+}
+
+NEXTPNR_NAMESPACE_END
+
+#endif // NO_PYTHON
\ No newline at end of file
diff --git a/common/kernel/hashlib.h b/common/kernel/hashlib.h
new file mode 100644
index 00000000..2f7357e2
--- /dev/null
+++ b/common/kernel/hashlib.h
@@ -0,0 +1,1210 @@
+// This is free and unencumbered software released into the public domain.
+//
+// Anyone is free to copy, modify, publish, use, compile, sell, or
+// distribute this software, either in source code form or as a compiled
+// binary, for any purpose, commercial or non-commercial, and by any
+// means.
+
+// -------------------------------------------------------
+// Written by Claire Xen <claire@clairexen.net> in 2014
+// -------------------------------------------------------
+
+#ifndef HASHLIB_H
+#define HASHLIB_H
+
+#include <algorithm>
+#include <array>
+#include <stdexcept>
+#include <string>
+#include <vector>
+
+#include "nextpnr_assertions.h"
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+const int hashtable_size_trigger = 2;
+const int hashtable_size_factor = 3;
+
+// Cantor pairing function for two non-negative integers
+// https://en.wikipedia.org/wiki/Pairing_function
+inline unsigned int mkhash(unsigned int a, unsigned int b) { return (a * a + 3 * a + 2 * a * b + b + b * b) / 2; }
+
+// traditionally 5381 is used as starting value for the djb2 hash
+const unsigned int mkhash_init = 5381;
+
+// The ADD version of DJB2
+// (use this version for cache locality in b)
+inline unsigned int mkhash_add(unsigned int a, unsigned int b) { return ((a << 5) + a) + b; }
+
+inline unsigned int mkhash_xorshift(unsigned int a)
+{
+    if (sizeof(a) == 4) {
+        a ^= a << 13;
+        a ^= a >> 17;
+        a ^= a << 5;
+    } else if (sizeof(a) == 8) {
+        a ^= a << 13;
+        a ^= a >> 7;
+        a ^= a << 17;
+    } else
+        NPNR_ASSERT_FALSE("mkhash_xorshift() only implemented for 32 bit and 64 bit ints");
+    return a;
+}
+
+template <typename T> struct hash_ops
+{
+    static inline bool cmp(const T &a, const T &b) { return a == b; }
+    static inline unsigned int hash(const T &a) { return a.hash(); }
+};
+
+struct hash_int_ops
+{
+    template <typename T> static inline bool cmp(T a, T b) { return a == b; }
+};
+
+template <> struct hash_ops<bool> : hash_int_ops
+{
+    static inline unsigned int hash(bool a) { return a ? 1 : 0; }
+};
+template <> struct hash_ops<int32_t> : hash_int_ops
+{
+    static inline unsigned int hash(int32_t a) { return a; }
+};
+template <> struct hash_ops<int64_t> : hash_int_ops
+{
+    static inline unsigned int hash(int64_t a) { return mkhash((unsigned int)(a), (unsigned int)(a >> 32)); }
+};
+
+template <> struct hash_ops<uint32_t> : hash_int_ops
+{
+    static inline unsigned int hash(uint32_t a) { return a; }
+};
+template <> struct hash_ops<uint64_t> : hash_int_ops
+{
+    static inline unsigned int hash(uint64_t a) { return mkhash((unsigned int)(a), (unsigned int)(a >> 32)); }
+};
+
+template <> struct hash_ops<std::string>
+{
+    static inline bool cmp(const std::string &a, const std::string &b) { return a == b; }
+    static inline unsigned int hash(const std::string &a)
+    {
+        unsigned int v = 0;
+        for (auto c : a)
+            v = mkhash(v, c);
+        return v;
+    }
+};
+
+template <typename P, typename Q> struct hash_ops<std::pair<P, Q>>
+{
+    static inline bool cmp(std::pair<P, Q> a, std::pair<P, Q> b) { return a == b; }
+    static inline unsigned int hash(std::pair<P, Q> a)
+    {
+        return mkhash(hash_ops<P>::hash(a.first), hash_ops<Q>::hash(a.second));
+    }
+};
+
+template <typename... T> struct hash_ops<std::tuple<T...>>
+{
+    static inline bool cmp(std::tuple<T...> a, std::tuple<T...> b) { return a == b; }
+    template <size_t I = 0>
+    static inline typename std::enable_if<I == sizeof...(T), unsigned int>::type hash(std::tuple<T...>)
+    {
+        return mkhash_init;
+    }
+    template <size_t I = 0>
+    static inline typename std::enable_if<I != sizeof...(T), unsigned int>::type hash(std::tuple<T...> a)
+    {
+        typedef hash_ops<typename std::tuple_element<I, std::tuple<T...>>::type> element_ops_t;
+        return mkhash(hash<I + 1>(a), element_ops_t::hash(std::get<I>(a)));
+    }
+};
+
+template <typename T> struct hash_ops<std::vector<T>>
+{
+    static inline bool cmp(std::vector<T> a, std::vector<T> b) { return a == b; }
+    static inline unsigned int hash(std::vector<T> a)
+    {
+        unsigned int h = mkhash_init;
+        for (auto k : a)
+            h = mkhash(h, hash_ops<T>::hash(k));
+        return h;
+    }
+};
+
+template <typename T, size_t N> struct hash_ops<std::array<T, N>>
+{
+    static inline bool cmp(std::array<T, N> a, std::array<T, N> b) { return a == b; }
+    static inline unsigned int hash(std::array<T, N> a)
+    {
+        unsigned int h = mkhash_init;
+        for (auto k : a)
+            h = mkhash(h, hash_ops<T>::hash(k));
+        return h;
+    }
+};
+
+struct hash_cstr_ops
+{
+    static inline bool cmp(const char *a, const char *b)
+    {
+        for (int i = 0; a[i] || b[i]; i++)
+            if (a[i] != b[i])
+                return false;
+        return true;
+    }
+    static inline unsigned int hash(const char *a)
+    {
+        unsigned int hash = mkhash_init;
+        while (*a)
+            hash = mkhash(hash, *(a++));
+        return hash;
+    }
+};
+
+struct hash_ptr_ops
+{
+    static inline bool cmp(const void *a, const void *b) { return a == b; }
+    static inline unsigned int hash(const void *a) { return (uintptr_t)a; }
+};
+
+struct hash_obj_ops
+{
+    static inline bool cmp(const void *a, const void *b) { return a == b; }
+    template <typename T> static inline unsigned int hash(const T *a) { return a ? a->hash() : 0; }
+};
+
+template <typename T> inline unsigned int mkhash(const T &v) { return hash_ops<T>().hash(v); }
+
+inline int hashtable_size(int min_size)
+{
+    static std::vector<int> zero_and_some_primes = {
+            0,         23,        29,        37,        47,       59,       79,       101,      127,      163,
+            211,       269,       337,       431,       541,      677,      853,      1069,     1361,     1709,
+            2137,      2677,      3347,      4201,      5261,     6577,     8231,     10289,    12889,    16127,
+            20161,     25219,     31531,     39419,     49277,    61603,    77017,    96281,    120371,   150473,
+            188107,    235159,    293957,    367453,    459317,   574157,   717697,   897133,   1121423,  1401791,
+            1752239,   2190299,   2737937,   3422429,   4278037,  5347553,  6684443,  8355563,  10444457, 13055587,
+            16319519,  20399411,  25499291,  31874149,  39842687, 49803361, 62254207, 77817767, 97272239, 121590311,
+            151987889, 189984863, 237481091, 296851369, 371064217};
+
+    for (auto p : zero_and_some_primes)
+        if (p >= min_size)
+            return p;
+
+    if (sizeof(int) == 4)
+        throw std::length_error("hash table exceeded maximum size. use a ILP64 abi for larger tables.");
+
+    for (auto p : zero_and_some_primes)
+        if (100129 * p > min_size)
+            return 100129 * p;
+
+    throw std::length_error("hash table exceeded maximum size.");
+}
+
+template <typename K, typename T, typename OPS = hash_ops<K>> class dict;
+template <typename K, int offset = 0, typename OPS = hash_ops<K>> class idict;
+template <typename K, typename OPS = hash_ops<K>> class pool;
+template <typename K, typename OPS = hash_ops<K>> class mfp;
+
+template <typename K, typename T, typename OPS> class dict
+{
+    struct entry_t
+    {
+        std::pair<K, T> udata;
+        int next;
+
+        entry_t() {}
+        entry_t(const std::pair<K, T> &udata, int next) : udata(udata), next(next) {}
+        entry_t(std::pair<K, T> &&udata, int next) : udata(std::move(udata)), next(next) {}
+        bool operator<(const entry_t &other) const { return udata.first < other.udata.first; }
+    };
+
+    std::vector<int> hashtable;
+    std::vector<entry_t> entries;
+    OPS ops;
+
+#ifdef NDEBUG
+    static inline void do_assert(bool) {}
+#else
+    static inline void do_assert(bool cond) { NPNR_ASSERT(cond); }
+#endif
+
+    int do_hash(const K &key) const
+    {
+        unsigned int hash = 0;
+        if (!hashtable.empty())
+            hash = ops.hash(key) % (unsigned int)(hashtable.size());
+        return hash;
+    }
+
+    void do_rehash()
+    {
+        hashtable.clear();
+        hashtable.resize(hashtable_size(entries.capacity() * hashtable_size_factor), -1);
+
+        for (int i = 0; i < int(entries.size()); i++) {
+            do_assert(-1 <= entries[i].next && entries[i].next < int(entries.size()));
+            int hash = do_hash(entries[i].udata.first);
+            entries[i].next = hashtable[hash];
+            hashtable[hash] = i;
+        }
+    }
+
+    int do_erase(int index, int hash)
+    {
+        do_assert(index < int(entries.size()));
+        if (hashtable.empty() || index < 0)
+            return 0;
+
+        int k = hashtable[hash];
+        do_assert(0 <= k && k < int(entries.size()));
+
+        if (k == index) {
+            hashtable[hash] = entries[index].next;
+        } else {
+            while (entries[k].next != index) {
+                k = entries[k].next;
+                do_assert(0 <= k && k < int(entries.size()));
+            }
+            entries[k].next = entries[index].next;
+        }
+
+        int back_idx = entries.size() - 1;
+
+        if (index != back_idx) {
+            int back_hash = do_hash(entries[back_idx].udata.first);
+
+            k = hashtable[back_hash];
+            do_assert(0 <= k && k < int(entries.size()));
+
+            if (k == back_idx) {
+                hashtable[back_hash] = index;
+            } else {
+                while (entries[k].next != back_idx) {
+                    k = entries[k].next;
+                    do_assert(0 <= k && k < int(entries.size()));
+                }
+                entries[k].next = index;
+            }
+
+            entries[index] = std::move(entries[back_idx]);
+        }
+
+        entries.pop_back();
+
+        if (entries.empty())
+            hashtable.clear();
+
+        return 1;
+    }
+
+    int do_lookup(const K &key, int &hash) const
+    {
+        if (hashtable.empty())
+            return -1;
+
+        if (entries.size() * hashtable_size_trigger > hashtable.size()) {
+            ((dict *)this)->do_rehash();
+            hash = do_hash(key);
+        }
+
+        int index = hashtable[hash];
+
+        while (index >= 0 && !ops.cmp(entries[index].udata.first, key)) {
+            index = entries[index].next;
+            do_assert(-1 <= index && index < int(entries.size()));
+        }
+
+        return index;
+    }
+
+    int do_insert(const K &key, int &hash)
+    {
+        if (hashtable.empty()) {
+            entries.emplace_back(std::pair<K, T>(key, T()), -1);
+            do_rehash();
+            hash = do_hash(key);
+        } else {
+            entries.emplace_back(std::pair<K, T>(key, T()), hashtable[hash]);
+            hashtable[hash] = entries.size() - 1;
+        }
+        return entries.size() - 1;
+    }
+
+    int do_insert(const std::pair<K, T> &value, int &hash)
+    {
+        if (hashtable.empty()) {
+            entries.emplace_back(value, -1);
+            do_rehash();
+            hash = do_hash(value.first);
+        } else {
+            entries.emplace_back(value, hashtable[hash]);
+            hashtable[hash] = entries.size() - 1;
+        }
+        return entries.size() - 1;
+    }
+
+    int do_insert(std::pair<K, T> &&rvalue, int &hash)
+    {
+        if (hashtable.empty()) {
+            auto key = rvalue.first;
+            entries.emplace_back(std::forward<std::pair<K, T>>(rvalue), -1);
+            do_rehash();
+            hash = do_hash(key);
+        } else {
+            entries.emplace_back(std::forward<std::pair<K, T>>(rvalue), hashtable[hash]);
+            hashtable[hash] = entries.size() - 1;
+        }
+        return entries.size() - 1;
+    }
+
+  public:
+    using key_type = K;
+    using mapped_type = T;
+    using value_type = std::pair<K, T>;
+
+    class const_iterator : public std::iterator<std::forward_iterator_tag, std::pair<K, T>>
+    {
+        friend class dict;
+
+      protected:
+        const dict *ptr;
+        int index;
+        const_iterator(const dict *ptr, int index) : ptr(ptr), index(index) {}
+
+      public:
+        const_iterator() {}
+        const_iterator operator++()
+        {
+            index--;
+            return *this;
+        }
+        const_iterator operator+=(int amt)
+        {
+            index -= amt;
+            return *this;
+        }
+        bool operator<(const const_iterator &other) const { return index > other.index; }
+        bool operator==(const const_iterator &other) const { return index == other.index; }
+        bool operator!=(const const_iterator &other) const { return index != other.index; }
+        const std::pair<K, T> &operator*() const { return ptr->entries[index].udata; }
+        const std::pair<K, T> *operator->() const { return &ptr->entries[index].udata; }
+    };
+
+    class iterator : public std::iterator<std::forward_iterator_tag, std::pair<K, T>>
+    {
+        friend class dict;
+
+      protected:
+        dict *ptr;
+        int index;
+        iterator(dict *ptr, int index) : ptr(ptr), index(index) {}
+
+      public:
+        iterator() {}
+        iterator operator++()
+        {
+            index--;
+            return *this;
+        }
+        iterator operator+=(int amt)
+        {
+            index -= amt;
+            return *this;
+        }
+        bool operator<(const iterator &other) const { return index > other.index; }
+        bool operator==(const iterator &other) const { return index == other.index; }
+        bool operator!=(const iterator &other) const { return index != other.index; }
+        std::pair<K, T> &operator*() { return ptr->entries[index].udata; }
+        std::pair<K, T> *operator->() { return &ptr->entries[index].udata; }
+        const std::pair<K, T> &operator*() const { return ptr->entries[index].udata; }
+        const std::pair<K, T> *operator->() const { return &ptr->entries[index].udata; }
+        operator const_iterator() const { return const_iterator(ptr, index); }
+    };
+
+    dict() {}
+
+    dict(const dict &other)
+    {
+        entries = other.entries;
+        do_rehash();
+    }
+
+    dict(dict &&other) { swap(other); }
+
+    dict &operator=(const dict &other)
+    {
+        entries = other.entries;
+        do_rehash();
+        return *this;
+    }
+
+    dict &operator=(dict &&other)
+    {
+        clear();
+        swap(other);
+        return *this;
+    }
+
+    dict(const std::initializer_list<std::pair<K, T>> &list)
+    {
+        for (auto &it : list)
+            insert(it);
+    }
+
+    template <class InputIterator> dict(InputIterator first, InputIterator last) { insert(first, last); }
+
+    template <class InputIterator> void insert(InputIterator first, InputIterator last)
+    {
+        for (; first != last; ++first)
+            insert(*first);
+    }
+
+    std::pair<iterator, bool> insert(const K &key)
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        if (i >= 0)
+            return std::pair<iterator, bool>(iterator(this, i), false);
+        i = do_insert(key, hash);
+        return std::pair<iterator, bool>(iterator(this, i), true);
+    }
+
+    std::pair<iterator, bool> insert(const std::pair<K, T> &value)
+    {
+        int hash = do_hash(value.first);
+        int i = do_lookup(value.first, hash);
+        if (i >= 0)
+            return std::pair<iterator, bool>(iterator(this, i), false);
+        i = do_insert(value, hash);
+        return std::pair<iterator, bool>(iterator(this, i), true);
+    }
+
+    std::pair<iterator, bool> insert(std::pair<K, T> &&rvalue)
+    {
+        int hash = do_hash(rvalue.first);
+        int i = do_lookup(rvalue.first, hash);
+        if (i >= 0)
+            return std::pair<iterator, bool>(iterator(this, i), false);
+        i = do_insert(std::forward<std::pair<K, T>>(rvalue), hash);
+        return std::pair<iterator, bool>(iterator(this, i), true);
+    }
+
+    std::pair<iterator, bool> emplace(K const &key, T const &value)
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        if (i >= 0)
+            return std::pair<iterator, bool>(iterator(this, i), false);
+        i = do_insert(std::make_pair(key, value), hash);
+        return std::pair<iterator, bool>(iterator(this, i), true);
+    }
+
+    std::pair<iterator, bool> emplace(K const &key, T &&rvalue)
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        if (i >= 0)
+            return std::pair<iterator, bool>(iterator(this, i), false);
+        i = do_insert(std::make_pair(key, std::forward<T>(rvalue)), hash);
+        return std::pair<iterator, bool>(iterator(this, i), true);
+    }
+
+    std::pair<iterator, bool> emplace(K &&rkey, T const &value)
+    {
+        int hash = do_hash(rkey);
+        int i = do_lookup(rkey, hash);
+        if (i >= 0)
+            return std::pair<iterator, bool>(iterator(this, i), false);
+        i = do_insert(std::make_pair(std::forward<K>(rkey), value), hash);
+        return std::pair<iterator, bool>(iterator(this, i), true);
+    }
+
+    std::pair<iterator, bool> emplace(K &&rkey, T &&rvalue)
+    {
+        int hash = do_hash(rkey);
+        int i = do_lookup(rkey, hash);
+        if (i >= 0)
+            return std::pair<iterator, bool>(iterator(this, i), false);
+        i = do_insert(std::make_pair(std::forward<K>(rkey), std::forward<T>(rvalue)), hash);
+        return std::pair<iterator, bool>(iterator(this, i), true);
+    }
+
+    int erase(const K &key)
+    {
+        int hash = do_hash(key);
+        int index = do_lookup(key, hash);
+        return do_erase(index, hash);
+    }
+
+    iterator erase(iterator it)
+    {
+        int hash = do_hash(it->first);
+        do_erase(it.index, hash);
+        return ++it;
+    }
+
+    int count(const K &key) const
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        return i < 0 ? 0 : 1;
+    }
+
+    int count(const K &key, const_iterator it) const
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        return i < 0 || i > it.index ? 0 : 1;
+    }
+
+    iterator find(const K &key)
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        if (i < 0)
+            return end();
+        return iterator(this, i);
+    }
+
+    const_iterator find(const K &key) const
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        if (i < 0)
+            return end();
+        return const_iterator(this, i);
+    }
+
+    T &at(const K &key)
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        if (i < 0)
+            throw std::out_of_range("dict::at()");
+        return entries[i].udata.second;
+    }
+
+    const T &at(const K &key) const
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        if (i < 0)
+            throw std::out_of_range("dict::at()");
+        return entries[i].udata.second;
+    }
+
+    const T &at(const K &key, const T &defval) const
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        if (i < 0)
+            return defval;
+        return entries[i].udata.second;
+    }
+
+    T &operator[](const K &key)
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        if (i < 0)
+            i = do_insert(std::pair<K, T>(key, T()), hash);
+        return entries[i].udata.second;
+    }
+
+    template <typename Compare = std::less<K>> void sort(Compare comp = Compare())
+    {
+        std::sort(entries.begin(), entries.end(),
+                  [comp](const entry_t &a, const entry_t &b) { return comp(b.udata.first, a.udata.first); });
+        do_rehash();
+    }
+
+    void swap(dict &other)
+    {
+        hashtable.swap(other.hashtable);
+        entries.swap(other.entries);
+    }
+
+    bool operator==(const dict &other) const
+    {
+        if (size() != other.size())
+            return false;
+        for (auto &it : entries) {
+            auto oit = other.find(it.udata.first);
+            if (oit == other.end() || !(oit->second == it.udata.second))
+                return false;
+        }
+        return true;
+    }
+
+    bool operator!=(const dict &other) const { return !operator==(other); }
+
+    unsigned int hash() const
+    {
+        unsigned int h = mkhash_init;
+        for (auto &entry : entries) {
+            h ^= hash_ops<K>::hash(entry.udata.first);
+            h ^= hash_ops<T>::hash(entry.udata.second);
+        }
+        return h;
+    }
+
+    void reserve(size_t n) { entries.reserve(n); }
+    size_t size() const { return entries.size(); }
+    bool empty() const { return entries.empty(); }
+    void clear()
+    {
+        hashtable.clear();
+        entries.clear();
+    }
+
+    iterator begin() { return iterator(this, int(entries.size()) - 1); }
+    iterator element(int n) { return iterator(this, int(entries.size()) - 1 - n); }
+    iterator end() { return iterator(nullptr, -1); }
+
+    const_iterator begin() const { return const_iterator(this, int(entries.size()) - 1); }
+    const_iterator element(int n) const { return const_iterator(this, int(entries.size()) - 1 - n); }
+    const_iterator end() const { return const_iterator(nullptr, -1); }
+};
+
+template <typename K, typename OPS> class pool
+{
+    template <typename, int, typename> friend class idict;
+
+  protected:
+    struct entry_t
+    {
+        K udata;
+        int next;
+
+        entry_t() {}
+        entry_t(const K &udata, int next) : udata(udata), next(next) {}
+        entry_t(K &&udata, int next) : udata(std::move(udata)), next(next) {}
+    };
+
+    std::vector<int> hashtable;
+    std::vector<entry_t> entries;
+    OPS ops;
+
+#ifdef NDEBUG
+    static inline void do_assert(bool) {}
+#else
+    static inline void do_assert(bool cond) { NPNR_ASSERT(cond); }
+#endif
+
+    int do_hash(const K &key) const
+    {
+        unsigned int hash = 0;
+        if (!hashtable.empty())
+            hash = ops.hash(key) % (unsigned int)(hashtable.size());
+        return hash;
+    }
+
+    void do_rehash()
+    {
+        hashtable.clear();
+        hashtable.resize(hashtable_size(entries.capacity() * hashtable_size_factor), -1);
+
+        for (int i = 0; i < int(entries.size()); i++) {
+            do_assert(-1 <= entries[i].next && entries[i].next < int(entries.size()));
+            int hash = do_hash(entries[i].udata);
+            entries[i].next = hashtable[hash];
+            hashtable[hash] = i;
+        }
+    }
+
+    int do_erase(int index, int hash)
+    {
+        do_assert(index < int(entries.size()));
+        if (hashtable.empty() || index < 0)
+            return 0;
+
+        int k = hashtable[hash];
+        if (k == index) {
+            hashtable[hash] = entries[index].next;
+        } else {
+            while (entries[k].next != index) {
+                k = entries[k].next;
+                do_assert(0 <= k && k < int(entries.size()));
+            }
+            entries[k].next = entries[index].next;
+        }
+
+        int back_idx = entries.size() - 1;
+
+        if (index != back_idx) {
+            int back_hash = do_hash(entries[back_idx].udata);
+
+            k = hashtable[back_hash];
+            if (k == back_idx) {
+                hashtable[back_hash] = index;
+            } else {
+                while (entries[k].next != back_idx) {
+                    k = entries[k].next;
+                    do_assert(0 <= k && k < int(entries.size()));
+                }
+                entries[k].next = index;
+            }
+
+            entries[index] = std::move(entries[back_idx]);
+        }
+
+        entries.pop_back();
+
+        if (entries.empty())
+            hashtable.clear();
+
+        return 1;
+    }
+
+    int do_lookup(const K &key, int &hash) const
+    {
+        if (hashtable.empty())
+            return -1;
+
+        if (entries.size() * hashtable_size_trigger > hashtable.size()) {
+            ((pool *)this)->do_rehash();
+            hash = do_hash(key);
+        }
+
+        int index = hashtable[hash];
+
+        while (index >= 0 && !ops.cmp(entries[index].udata, key)) {
+            index = entries[index].next;
+            do_assert(-1 <= index && index < int(entries.size()));
+        }
+
+        return index;
+    }
+
+    int do_insert(const K &value, int &hash)
+    {
+        if (hashtable.empty()) {
+            entries.emplace_back(value, -1);
+            do_rehash();
+            hash = do_hash(value);
+        } else {
+            entries.emplace_back(value, hashtable[hash]);
+            hashtable[hash] = entries.size() - 1;
+        }
+        return entries.size() - 1;
+    }
+
+    int do_insert(K &&rvalue, int &hash)
+    {
+        if (hashtable.empty()) {
+            entries.emplace_back(std::forward<K>(rvalue), -1);
+            do_rehash();
+            hash = do_hash(rvalue);
+        } else {
+            entries.emplace_back(std::forward<K>(rvalue), hashtable[hash]);
+            hashtable[hash] = entries.size() - 1;
+        }
+        return entries.size() - 1;
+    }
+
+  public:
+    class const_iterator : public std::iterator<std::forward_iterator_tag, K>
+    {
+        friend class pool;
+
+      protected:
+        const pool *ptr;
+        int index;
+        const_iterator(const pool *ptr, int index) : ptr(ptr), index(index) {}
+
+      public:
+        const_iterator() {}
+        const_iterator operator++()
+        {
+            index--;
+            return *this;
+        }
+        bool operator==(const const_iterator &other) const { return index == other.index; }
+        bool operator!=(const const_iterator &other) const { return index != other.index; }
+        const K &operator*() const { return ptr->entries[index].udata; }
+        const K *operator->() const { return &ptr->entries[index].udata; }
+    };
+
+    class iterator : public std::iterator<std::forward_iterator_tag, K>
+    {
+        friend class pool;
+
+      protected:
+        pool *ptr;
+        int index;
+        iterator(pool *ptr, int index) : ptr(ptr), index(index) {}
+
+      public:
+        iterator() {}
+        iterator operator++()
+        {
+            index--;
+            return *this;
+        }
+        bool operator==(const iterator &other) const { return index == other.index; }
+        bool operator!=(const iterator &other) const { return index != other.index; }
+        K &operator*() { return ptr->entries[index].udata; }
+        K *operator->() { return &ptr->entries[index].udata; }
+        const K &operator*() const { return ptr->entries[index].udata; }
+        const K *operator->() const { return &ptr->entries[index].udata; }
+        operator const_iterator() const { return const_iterator(ptr, index); }
+    };
+
+    pool() {}
+
+    pool(const pool &other)
+    {
+        entries = other.entries;
+        do_rehash();
+    }
+
+    pool(pool &&other) { swap(other); }
+
+    pool &operator=(const pool &other)
+    {
+        entries = other.entries;
+        do_rehash();
+        return *this;
+    }
+
+    pool &operator=(pool &&other)
+    {
+        clear();
+        swap(other);
+        return *this;
+    }
+
+    pool(const std::initializer_list<K> &list)
+    {
+        for (auto &it : list)
+            insert(it);
+    }
+
+    template <class InputIterator> pool(InputIterator first, InputIterator last) { insert(first, last); }
+
+    template <class InputIterator> void insert(InputIterator first, InputIterator last)
+    {
+        for (; first != last; ++first)
+            insert(*first);
+    }
+
+    std::pair<iterator, bool> insert(const K &value)
+    {
+        int hash = do_hash(value);
+        int i = do_lookup(value, hash);
+        if (i >= 0)
+            return std::pair<iterator, bool>(iterator(this, i), false);
+        i = do_insert(value, hash);
+        return std::pair<iterator, bool>(iterator(this, i), true);
+    }
+
+    std::pair<iterator, bool> insert(K &&rvalue)
+    {
+        int hash = do_hash(rvalue);
+        int i = do_lookup(rvalue, hash);
+        if (i >= 0)
+            return std::pair<iterator, bool>(iterator(this, i), false);
+        i = do_insert(std::forward<K>(rvalue), hash);
+        return std::pair<iterator, bool>(iterator(this, i), true);
+    }
+
+    template <typename... Args> std::pair<iterator, bool> emplace(Args &&...args)
+    {
+        return insert(K(std::forward<Args>(args)...));
+    }
+
+    int erase(const K &key)
+    {
+        int hash = do_hash(key);
+        int index = do_lookup(key, hash);
+        return do_erase(index, hash);
+    }
+
+    iterator erase(iterator it)
+    {
+        int hash = do_hash(*it);
+        do_erase(it.index, hash);
+        return ++it;
+    }
+
+    int count(const K &key) const
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        return i < 0 ? 0 : 1;
+    }
+
+    int count(const K &key, const_iterator it) const
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        return i < 0 || i > it.index ? 0 : 1;
+    }
+
+    iterator find(const K &key)
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        if (i < 0)
+            return end();
+        return iterator(this, i);
+    }
+
+    const_iterator find(const K &key) const
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        if (i < 0)
+            return end();
+        return const_iterator(this, i);
+    }
+
+    bool operator[](const K &key)
+    {
+        int hash = do_hash(key);
+        int i = do_lookup(key, hash);
+        return i >= 0;
+    }
+
+    template <typename Compare = std::less<K>> void sort(Compare comp = Compare())
+    {
+        std::sort(entries.begin(), entries.end(),
+                  [comp](const entry_t &a, const entry_t &b) { return comp(b.udata, a.udata); });
+        do_rehash();
+    }
+
+    K pop()
+    {
+        iterator it = begin();
+        K ret = *it;
+        erase(it);
+        return ret;
+    }
+
+    void swap(pool &other)
+    {
+        hashtable.swap(other.hashtable);
+        entries.swap(other.entries);
+    }
+
+    bool operator==(const pool &other) const
+    {
+        if (size() != other.size())
+            return false;
+        for (auto &it : entries)
+            if (!other.count(it.udata))
+                return false;
+        return true;
+    }
+
+    bool operator!=(const pool &other) const { return !operator==(other); }
+
+    bool hash() const
+    {
+        unsigned int hashval = mkhash_init;
+        for (auto &it : entries)
+            hashval ^= ops.hash(it.udata);
+        return hashval;
+    }
+
+    void reserve(size_t n) { entries.reserve(n); }
+    size_t size() const { return entries.size(); }
+    bool empty() const { return entries.empty(); }
+    void clear()
+    {
+        hashtable.clear();
+        entries.clear();
+    }
+
+    iterator begin() { return iterator(this, int(entries.size()) - 1); }
+    iterator element(int n) { return iterator(this, int(entries.size()) - 1 - n); }
+    iterator end() { return iterator(nullptr, -1); }
+
+    const_iterator begin() const { return const_iterator(this, int(entries.size()) - 1); }
+    const_iterator element(int n) const { return const_iterator(this, int(entries.size()) - 1 - n); }
+    const_iterator end() const { return const_iterator(nullptr, -1); }
+};
+
+template <typename K, int offset, typename OPS> class idict
+{
+    pool<K, OPS> database;
+
+  public:
+    class const_iterator : public std::iterator<std::forward_iterator_tag, K>
+    {
+        friend class idict;
+
+      protected:
+        const idict &container;
+        int index;
+        const_iterator(const idict &container, int index) : container(container), index(index) {}
+
+      public:
+        const_iterator() {}
+        const_iterator operator++()
+        {
+            index++;
+            return *this;
+        }
+        bool operator==(const const_iterator &other) const { return index == other.index; }
+        bool operator!=(const const_iterator &other) const { return index != other.index; }
+        const K &operator*() const { return container[index]; }
+        const K *operator->() const { return &container[index]; }
+    };
+
+    int operator()(const K &key)
+    {
+        int hash = database.do_hash(key);
+        int i = database.do_lookup(key, hash);
+        if (i < 0)
+            i = database.do_insert(key, hash);
+        return i + offset;
+    }
+
+    int at(const K &key) const
+    {
+        int hash = database.do_hash(key);
+        int i = database.do_lookup(key, hash);
+        if (i < 0)
+            throw std::out_of_range("idict::at()");
+        return i + offset;
+    }
+
+    int at(const K &key, int defval) const
+    {
+        int hash = database.do_hash(key);
+        int i = database.do_lookup(key, hash);
+        if (i < 0)
+            return defval;
+        return i + offset;
+    }
+
+    int count(const K &key) const
+    {
+        int hash = database.do_hash(key);
+        int i = database.do_lookup(key, hash);
+        return i < 0 ? 0 : 1;
+    }
+
+    void expect(const K &key, int i)
+    {
+        int j = (*this)(key);
+        if (i != j)
+            throw std::out_of_range("idict::expect()");
+    }
+
+    const K &operator[](int index) const { return database.entries.at(index - offset).udata; }
+
+    void swap(idict &other) { database.swap(other.database); }
+
+    void reserve(size_t n) { database.reserve(n); }
+    size_t size() const { return database.size(); }
+    bool empty() const { return database.empty(); }
+    void clear() { database.clear(); }
+
+    const_iterator begin() const { return const_iterator(*this, offset); }
+    const_iterator element(int n) const { return const_iterator(*this, n); }
+    const_iterator end() const { return const_iterator(*this, offset + size()); }
+};
+
+template <typename K, typename OPS> class mfp
+{
+    mutable idict<K, 0, OPS> database;
+    mutable std::vector<int> parents;
+
+  public:
+    typedef typename idict<K, 0, OPS>::const_iterator const_iterator;
+
+    int operator()(const K &key) const
+    {
+        int i = database(key);
+        parents.resize(database.size(), -1);
+        return i;
+    }
+
+    const K &operator[](int index) const { return database[index]; }
+
+    int ifind(int i) const
+    {
+        int p = i, k = i;
+
+        while (parents[p] != -1)
+            p = parents[p];
+
+        while (k != p) {
+            int next_k = parents[k];
+            parents[k] = p;
+            k = next_k;
+        }
+
+        return p;
+    }
+
+    void imerge(int i, int j)
+    {
+        i = ifind(i);
+        j = ifind(j);
+
+        if (i != j)
+            parents[i] = j;
+    }
+
+    void ipromote(int i)
+    {
+        int k = i;
+
+        while (k != -1) {
+            int next_k = parents[k];
+            parents[k] = i;
+            k = next_k;
+        }
+
+        parents[i] = -1;
+    }
+
+    int lookup(const K &a) const { return ifind((*this)(a)); }
+
+    const K &find(const K &a) const
+    {
+        int i = database.at(a, -1);
+        if (i < 0)
+            return a;
+        return (*this)[ifind(i)];
+    }
+
+    void merge(const K &a, const K &b) { imerge((*this)(a), (*this)(b)); }
+
+    void promote(const K &a)
+    {
+        int i = database.at(a, -1);
+        if (i >= 0)
+            ipromote(i);
+    }
+
+    void swap(mfp &other)
+    {
+        database.swap(other.database);
+        parents.swap(other.parents);
+    }
+
+    void reserve(size_t n) { database.reserve(n); }
+    size_t size() const { return database.size(); }
+    bool empty() const { return database.empty(); }
+    void clear()
+    {
+        database.clear();
+        parents.clear();
+    }
+
+    const_iterator begin() const { return database.begin(); }
+    const_iterator element(int n) const { return database.element(n); }
+    const_iterator end() const { return database.end(); }
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/idstring.cc b/common/kernel/idstring.cc
new file mode 100644
index 00000000..9e27ac6f
--- /dev/null
+++ b/common/kernel/idstring.cc
@@ -0,0 +1,51 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "idstring.h"
+
+#include "basectx.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+void IdString::set(const BaseCtx *ctx, const std::string &s)
+{
+    auto it = ctx->idstring_str_to_idx->find(s);
+    if (it == ctx->idstring_str_to_idx->end()) {
+        index = ctx->idstring_idx_to_str->size();
+        auto insert_rc = ctx->idstring_str_to_idx->insert({s, index});
+        ctx->idstring_idx_to_str->push_back(&insert_rc.first->first);
+    } else {
+        index = it->second;
+    }
+}
+
+const std::string &IdString::str(const BaseCtx *ctx) const { return *ctx->idstring_idx_to_str->at(index); }
+
+const char *IdString::c_str(const BaseCtx *ctx) const { return str(ctx).c_str(); }
+
+void IdString::initialize_add(const BaseCtx *ctx, const char *s, int idx)
+{
+    NPNR_ASSERT(ctx->idstring_str_to_idx->count(s) == 0);
+    NPNR_ASSERT(int(ctx->idstring_idx_to_str->size()) == idx);
+    auto insert_rc = ctx->idstring_str_to_idx->insert({s, idx});
+    ctx->idstring_idx_to_str->push_back(&insert_rc.first->first);
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/idstring.h b/common/kernel/idstring.h
new file mode 100644
index 00000000..019e0a2a
--- /dev/null
+++ b/common/kernel/idstring.h
@@ -0,0 +1,75 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef IDSTRING_H
+#define IDSTRING_H
+
+#include <string>
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct BaseCtx;
+
+struct IdString
+{
+    int index;
+
+    static void initialize_arch(const BaseCtx *ctx);
+
+    static void initialize_add(const BaseCtx *ctx, const char *s, int idx);
+
+    constexpr IdString() : index(0) {}
+    explicit constexpr IdString(int index) : index(index) {}
+
+    void set(const BaseCtx *ctx, const std::string &s);
+
+    IdString(const BaseCtx *ctx, const std::string &s) { set(ctx, s); }
+
+    IdString(const BaseCtx *ctx, const char *s) { set(ctx, s); }
+
+    const std::string &str(const BaseCtx *ctx) const;
+
+    const char *c_str(const BaseCtx *ctx) const;
+
+    bool operator<(const IdString &other) const { return index < other.index; }
+
+    bool operator==(const IdString &other) const { return index == other.index; }
+
+    bool operator!=(const IdString &other) const { return index != other.index; }
+
+    bool empty() const { return index == 0; }
+
+    unsigned int hash() const { return index; }
+
+    template <typename... Args> bool in(Args... args) const
+    {
+        // Credit: https://articles.emptycrate.com/2016/05/14/folds_in_cpp11_ish.html
+        bool result = false;
+        (void)std::initializer_list<int>{(result = result || in(args), 0)...};
+        return result;
+    }
+
+    bool in(const IdString &rhs) const { return *this == rhs; }
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* IDSTRING_H */
diff --git a/common/kernel/idstringlist.cc b/common/kernel/idstringlist.cc
new file mode 100644
index 00000000..624622cf
--- /dev/null
+++ b/common/kernel/idstringlist.cc
@@ -0,0 +1,80 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "idstringlist.h"
+#include "context.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+IdStringList IdStringList::parse(Context *ctx, const std::string &str)
+{
+    char delim = ctx->getNameDelimiter();
+    size_t id_count = std::count(str.begin(), str.end(), delim) + 1;
+    IdStringList list(id_count);
+    size_t start = 0;
+    for (size_t i = 0; i < id_count; i++) {
+        size_t end = str.find(delim, start);
+        NPNR_ASSERT((i == (id_count - 1)) || (end != std::string::npos));
+        list.ids[i] = ctx->id(str.substr(start, end - start));
+        start = end + 1;
+    }
+    return list;
+}
+
+void IdStringList::build_str(const Context *ctx, std::string &str) const
+{
+    char delim = ctx->getNameDelimiter();
+    bool first = true;
+    str.clear();
+    for (auto entry : ids) {
+        if (!first)
+            str += delim;
+        str += entry.str(ctx);
+        first = false;
+    }
+}
+
+std::string IdStringList::str(const Context *ctx) const
+{
+    std::string s;
+    build_str(ctx, s);
+    return s;
+}
+
+IdStringList IdStringList::concat(IdStringList a, IdStringList b)
+{
+    IdStringList result(a.size() + b.size());
+    for (size_t i = 0; i < a.size(); i++)
+        result.ids[i] = a[i];
+    for (size_t i = 0; i < b.size(); i++)
+        result.ids[a.size() + i] = b[i];
+    return result;
+}
+
+IdStringList IdStringList::slice(size_t s, size_t e) const
+{
+    NPNR_ASSERT(e >= s);
+    IdStringList result(e - s);
+    for (size_t i = 0; i < result.size(); i++)
+        result.ids[i] = ids[s + i];
+    return result;
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/idstringlist.h b/common/kernel/idstringlist.h
new file mode 100644
index 00000000..5e462d0e
--- /dev/null
+++ b/common/kernel/idstringlist.h
@@ -0,0 +1,87 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef IDSTRING_LIST_H
+#define IDSTRING_LIST_H
+
+#include <boost/functional/hash.hpp>
+#include "hashlib.h"
+#include "idstring.h"
+#include "nextpnr_namespaces.h"
+#include "sso_array.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct Context;
+
+struct IdStringList
+{
+    SSOArray<IdString, 4> ids;
+
+    IdStringList() : ids(1, IdString()){};
+    explicit IdStringList(size_t n) : ids(n, IdString()){};
+    explicit IdStringList(IdString id) : ids(1, id){};
+    template <typename Tlist> explicit IdStringList(const Tlist &list) : ids(list){};
+
+    static IdStringList parse(Context *ctx, const std::string &str);
+    void build_str(const Context *ctx, std::string &str) const;
+    std::string str(const Context *ctx) const;
+
+    size_t size() const { return ids.size(); }
+    const IdString *begin() const { return ids.begin(); }
+    const IdString *end() const { return ids.end(); }
+    const IdString &operator[](size_t idx) const { return ids[idx]; }
+    bool operator==(const IdStringList &other) const { return ids == other.ids; }
+    bool operator!=(const IdStringList &other) const { return ids != other.ids; }
+    bool operator<(const IdStringList &other) const
+    {
+        if (size() > other.size())
+            return false;
+        if (size() < other.size())
+            return true;
+        for (size_t i = 0; i < size(); i++) {
+            IdString a = ids[i], b = other[i];
+            if (a.index < b.index)
+                return true;
+            if (a.index > b.index)
+                return false;
+        }
+        return false;
+    }
+
+    static IdStringList concat(IdStringList a, IdStringList b);
+    static IdStringList concat(IdString a, IdString b) { return concat(IdStringList(a), IdStringList(b)); }
+    static IdStringList concat(IdStringList a, IdString b) { return concat(a, IdStringList(b)); }
+    static IdStringList concat(IdString a, IdStringList b) { return concat(IdStringList(a), b); }
+
+    IdStringList slice(size_t s, size_t e) const;
+
+    unsigned int hash() const
+    {
+        unsigned int h = mkhash_init;
+        for (const auto &val : ids)
+            h = mkhash(h, val.hash());
+        return h;
+    }
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* IDSTRING_LIST_H */
diff --git a/common/kernel/indexed_store.h b/common/kernel/indexed_store.h
new file mode 100644
index 00000000..df607c13
--- /dev/null
+++ b/common/kernel/indexed_store.h
@@ -0,0 +1,297 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2021-22  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef INDEXED_STORE_H
+#define INDEXED_STORE_H
+
+#include <algorithm>
+#include <limits>
+#include <type_traits>
+#include <vector>
+
+#include "nextpnr_assertions.h"
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+template <typename T> struct store_index
+{
+    int32_t m_index = -1;
+    store_index() = default;
+    explicit store_index(int32_t index) : m_index(index){};
+    int32_t idx() const { return m_index; }
+    void set(int32_t index) { m_index = index; }
+    bool empty() const { return m_index == -1; }
+    bool operator==(const store_index<T> &other) const { return m_index == other.m_index; }
+    bool operator!=(const store_index<T> &other) const { return m_index != other.m_index; }
+    bool operator<(const store_index<T> &other) const { return m_index < other.m_index; }
+    unsigned int hash() const { return m_index; }
+
+    operator bool() const { return !empty(); }
+    operator int() const = delete;
+    bool operator!() const { return empty(); }
+};
+
+// "Slotted" indexed object store
+template <typename T> class indexed_store
+{
+  private:
+    // This should move to using std::optional at some point
+    class slot
+    {
+      private:
+        alignas(T) unsigned char storage[sizeof(T)];
+        int32_t next_free;
+        bool active;
+        inline T &obj() { return reinterpret_cast<T &>(storage); }
+        inline const T &obj() const { return reinterpret_cast<const T &>(storage); }
+        friend class indexed_store<T>;
+
+      public:
+        slot() : next_free(std::numeric_limits<int32_t>::max()), active(false){};
+        slot(slot &&other) : next_free(other.next_free), active(other.active)
+        {
+            if (active)
+                ::new (static_cast<void *>(&storage)) T(std::move(other.obj()));
+        };
+
+        slot(const slot &other) : next_free(other.next_free), active(other.active)
+        {
+            if (active)
+                ::new (static_cast<void *>(&storage)) T(other.obj());
+        };
+
+        template <class... Args> void create(Args &&...args)
+        {
+            NPNR_ASSERT(!active);
+            active = true;
+            ::new (static_cast<void *>(&storage)) T(std::forward<Args &&>(args)...);
+        }
+        bool empty() const { return !active; }
+        T &get()
+        {
+            NPNR_ASSERT(active);
+            return reinterpret_cast<T &>(storage);
+        }
+        const T &get() const
+        {
+            NPNR_ASSERT(active);
+            return reinterpret_cast<const T &>(storage);
+        }
+        void free(int32_t first_free)
+        {
+            NPNR_ASSERT(active);
+            obj().~T();
+            active = false;
+            next_free = first_free;
+        }
+        ~slot()
+        {
+            if (active)
+                obj().~T();
+        }
+    };
+
+    std::vector<slot> slots;
+    int32_t first_free = 0;
+    int32_t active_count = 0;
+
+  public:
+    // Create a new entry and return its index
+    template <class... Args> store_index<T> add(Args &&...args)
+    {
+        ++active_count;
+        if (first_free == int32_t(slots.size())) {
+            slots.emplace_back();
+            slots.back().create(std::forward<Args &&>(args)...);
+            ++first_free;
+            return store_index<T>(int32_t(slots.size()) - 1);
+        } else {
+            int32_t idx = first_free;
+            auto &slot = slots.at(idx);
+            first_free = slot.next_free;
+            slot.create(std::forward<Args &&>(args)...);
+            return store_index<T>(idx);
+        }
+    }
+
+    // Remove an entry at an index
+    void remove(store_index<T> idx)
+    {
+        --active_count;
+        slots.at(idx.m_index).free(first_free);
+        first_free = idx.m_index;
+    }
+
+    void clear()
+    {
+        active_count = 0;
+        first_free = 0;
+        slots.clear();
+    }
+
+    // Number of live entries
+    int32_t entries() const { return active_count; }
+    bool empty() const { return (entries() == 0); }
+
+    // Reserve a certain amount of space
+    void reserve(int32_t size) { slots.reserve(size); }
+
+    // Check if an index exists
+    int32_t count(store_index<T> idx)
+    {
+        if (idx.m_index < 0 || idx.m_index >= int32_t(slots.size()))
+            return 0;
+        return slots.at(idx.m_index).empty() ? 0 : 1;
+    }
+
+    // Get an item by index
+    T &at(store_index<T> idx) { return slots.at(idx.m_index).get(); }
+    const T &at(store_index<T> idx) const { return slots.at(idx.m_index).get(); }
+    T &operator[](store_index<T> idx) { return slots.at(idx.m_index).get(); }
+    const T &operator[](store_index<T> idx) const { return slots.at(idx.m_index).get(); }
+
+    // Total size of the container
+    int32_t capacity() const { return int32_t(slots.size()); }
+
+    // Iterate over items
+    template <typename It, typename S> class enumerated_iterator;
+
+    class iterator
+    {
+      private:
+        indexed_store *base;
+        int32_t index = 0;
+
+      public:
+        iterator(indexed_store *base, int32_t index) : base(base), index(index){};
+        inline bool operator!=(const iterator &other) const { return other.index != index; }
+        inline bool operator==(const iterator &other) const { return other.index == index; }
+        inline iterator operator++()
+        {
+            // skip over unused slots
+            do {
+                index++;
+            } while (index < int32_t(base->slots.size()) && !base->slots.at(index).active);
+            return *this;
+        }
+        inline iterator operator++(int)
+        {
+            iterator prior(*this);
+            do {
+                index++;
+            } while (index < int32_t(base->slots.size()) && !base->slots.at(index).active);
+            return prior;
+        }
+        T &operator*() { return base->at(store_index<T>(index)); }
+        template <typename It, typename S> friend class indexed_store::enumerated_iterator;
+    };
+    iterator begin()
+    {
+        auto it = iterator{this, -1};
+        ++it;
+        return it;
+    }
+    iterator end() { return iterator{this, int32_t(slots.size())}; }
+
+    class const_iterator
+    {
+      private:
+        const indexed_store *base;
+        int32_t index = 0;
+
+      public:
+        const_iterator(const indexed_store *base, int32_t index) : base(base), index(index){};
+        inline bool operator!=(const const_iterator &other) const { return other.index != index; }
+        inline bool operator==(const const_iterator &other) const { return other.index == index; }
+        inline const_iterator operator++()
+        {
+            // skip over unused slots
+            do {
+                index++;
+            } while (index < int32_t(base->slots.size()) && !base->slots.at(index).active);
+            return *this;
+        }
+        inline const_iterator operator++(int)
+        {
+            iterator prior(*this);
+            do {
+                index++;
+            } while (index < int32_t(base->slots.size()) && !base->slots.at(index).active);
+            return prior;
+        }
+        const T &operator*() { return base->at(store_index<T>(index)); }
+        template <typename It, typename S> friend class indexed_store::enumerated_iterator;
+    };
+    const_iterator begin() const
+    {
+        auto it = const_iterator{this, -1};
+        ++it;
+        return it;
+    }
+    const_iterator end() const { return const_iterator{this, int32_t(slots.size())}; }
+
+    template <typename S> struct enumerated_item
+    {
+        enumerated_item(int32_t index, T &value) : index(index), value(value){};
+        store_index<std::remove_cv_t<S>> index;
+        S &value;
+    };
+
+    template <typename It, typename S> class enumerated_iterator
+    {
+      private:
+        It base;
+
+      public:
+        enumerated_iterator(const It &base) : base(base){};
+        inline bool operator!=(const enumerated_iterator<It, S> &other) const { return other.base != base; }
+        inline bool operator==(const enumerated_iterator<It, S> &other) const { return other.base == base; }
+        inline enumerated_iterator<It, S> operator++()
+        {
+            ++base;
+            return *this;
+        }
+        inline enumerated_iterator<It, S> operator++(int)
+        {
+            iterator prior(*this);
+            ++base;
+            return prior;
+        }
+        enumerated_item<S> operator*() { return enumerated_item<S>{base.index, *base}; }
+    };
+
+    template <typename It, typename S> struct enumerated_range
+    {
+        enumerated_range(const It &begin, const It &end) : m_begin(begin), m_end(end){};
+        enumerated_iterator<It, S> m_begin, m_end;
+        enumerated_iterator<It, S> begin() { return m_begin; }
+        enumerated_iterator<It, S> end() { return m_end; }
+    };
+
+    enumerated_range<iterator, T> enumerate() { return enumerated_range<iterator, T>{begin(), end()}; }
+    enumerated_range<const_iterator, const T> enumerate() const
+    {
+        return enumerated_range<iterator, T>{begin(), end()};
+    }
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/log.cc b/common/kernel/log.cc
new file mode 100644
index 00000000..8b1ad43b
--- /dev/null
+++ b/common/kernel/log.cc
@@ -0,0 +1,198 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <list>
+#include <map>
+#include <set>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <vector>
+
+#include "log.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+NPNR_NORETURN void logv_error(const char *format, va_list ap) NPNR_ATTRIBUTE(noreturn);
+
+std::vector<std::pair<std::ostream *, LogLevel>> log_streams;
+log_write_type log_write_function = nullptr;
+
+std::string log_last_error;
+void (*log_error_atexit)() = NULL;
+
+dict<LogLevel, int, loglevel_hash_ops> message_count_by_level;
+static int log_newline_count = 0;
+bool had_nonfatal_error = false;
+
+std::string stringf(const char *fmt, ...)
+{
+    std::string string;
+    va_list ap;
+
+    va_start(ap, fmt);
+    string = vstringf(fmt, ap);
+    va_end(ap);
+
+    return string;
+}
+
+std::string vstringf(const char *fmt, va_list ap)
+{
+    std::string string;
+    char *str = NULL;
+
+#if defined(_WIN32) || defined(__CYGWIN__)
+    int sz = 64 + strlen(fmt), rc;
+    while (1) {
+        va_list apc;
+        va_copy(apc, ap);
+        str = (char *)realloc(str, sz);
+        rc = vsnprintf(str, sz, fmt, apc);
+        va_end(apc);
+        if (rc >= 0 && rc < sz)
+            break;
+        sz *= 2;
+    }
+#else
+    if (vasprintf(&str, fmt, ap) < 0)
+        str = NULL;
+#endif
+
+    if (str != NULL) {
+        string = str;
+        free(str);
+    }
+
+    return string;
+}
+
+void logv(const char *format, va_list ap, LogLevel level = LogLevel::LOG_MSG)
+{
+    //
+    // Trim newlines from the beginning
+    while (format[0] == '\n' && format[1] != 0) {
+        log_always("\n");
+        format++;
+    }
+
+    std::string str = vstringf(format, ap);
+
+    if (str.empty())
+        return;
+
+    size_t nnl_pos = str.find_last_not_of('\n');
+    if (nnl_pos == std::string::npos)
+        log_newline_count += str.size();
+    else
+        log_newline_count = str.size() - nnl_pos - 1;
+
+    for (auto f : log_streams)
+        if (f.second <= level)
+            *f.first << str;
+    if (log_write_function)
+        log_write_function(str);
+}
+
+void log_with_level(LogLevel level, const char *format, ...)
+{
+    message_count_by_level[level]++;
+    va_list ap;
+    va_start(ap, format);
+    logv(format, ap, level);
+    va_end(ap);
+}
+
+void logv_prefixed(const char *prefix, const char *format, va_list ap, LogLevel level)
+{
+    std::string message = vstringf(format, ap);
+
+    log_with_level(level, "%s%s", prefix, message.c_str());
+    log_flush();
+}
+
+void log_always(const char *format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    logv(format, ap, LogLevel::ALWAYS_MSG);
+    va_end(ap);
+}
+
+void log(const char *format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    logv(format, ap, LogLevel::LOG_MSG);
+    va_end(ap);
+}
+
+void log_info(const char *format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    logv_prefixed("Info: ", format, ap, LogLevel::INFO_MSG);
+    va_end(ap);
+}
+
+void log_warning(const char *format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    logv_prefixed("Warning: ", format, ap, LogLevel::WARNING_MSG);
+    va_end(ap);
+}
+
+void log_error(const char *format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    logv_prefixed("ERROR: ", format, ap, LogLevel::ERROR_MSG);
+
+    if (log_error_atexit)
+        log_error_atexit();
+
+    throw log_execution_error_exception();
+}
+
+void log_break()
+{
+    if (log_newline_count < 2)
+        log("\n");
+    if (log_newline_count < 2)
+        log("\n");
+}
+
+void log_nonfatal_error(const char *format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    logv_prefixed("ERROR: ", format, ap, LogLevel::ERROR_MSG);
+    va_end(ap);
+    had_nonfatal_error = true;
+}
+
+void log_flush()
+{
+    for (auto f : log_streams)
+        f.first->flush();
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/log.h b/common/kernel/log.h
new file mode 100644
index 00000000..0ac4edf5
--- /dev/null
+++ b/common/kernel/log.h
@@ -0,0 +1,92 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef LOG_H
+#define LOG_H
+
+#include <functional>
+#include <ostream>
+#include <set>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string>
+#include <vector>
+#include "hashlib.h"
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+typedef std::function<void(std::string)> log_write_type;
+
+struct log_cmd_error_exception
+{
+};
+
+struct log_execution_error_exception
+{
+};
+
+enum class LogLevel
+{
+    LOG_MSG,
+    INFO_MSG,
+    WARNING_MSG,
+    ERROR_MSG,
+    ALWAYS_MSG
+};
+
+struct loglevel_hash_ops
+{
+    static inline bool cmp(LogLevel a, LogLevel b) { return a == b; }
+    static inline unsigned int hash(LogLevel a) { return unsigned(a); }
+};
+
+extern std::vector<std::pair<std::ostream *, LogLevel>> log_streams;
+extern log_write_type log_write_function;
+
+extern std::string log_last_error;
+extern void (*log_error_atexit)();
+extern bool had_nonfatal_error;
+extern dict<LogLevel, int, loglevel_hash_ops> message_count_by_level;
+
+std::string stringf(const char *fmt, ...);
+std::string vstringf(const char *fmt, va_list ap);
+
+void log(const char *format, ...) NPNR_ATTRIBUTE(format(printf, 1, 2));
+void log_always(const char *format, ...) NPNR_ATTRIBUTE(format(printf, 1, 2));
+void log_info(const char *format, ...) NPNR_ATTRIBUTE(format(printf, 1, 2));
+void log_warning(const char *format, ...) NPNR_ATTRIBUTE(format(printf, 1, 2));
+NPNR_NORETURN void log_error(const char *format, ...) NPNR_ATTRIBUTE(format(printf, 1, 2), noreturn);
+void log_nonfatal_error(const char *format, ...) NPNR_ATTRIBUTE(format(printf, 1, 2));
+void log_break();
+void log_flush();
+
+static inline void log_assert_worker(bool cond, const char *expr, const char *file, int line)
+{
+    if (!cond)
+        log_error("Assert `%s' failed in %s:%d.\n", expr, file, line);
+}
+#define log_assert(_assert_expr_)                                                                                      \
+    NEXTPNR_NAMESPACE_PREFIX log_assert_worker(_assert_expr_, #_assert_expr_, __FILE__, __LINE__)
+
+#define log_abort() log_error("Abort in %s:%d.\n", __FILE__, __LINE__)
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/nextpnr.cc b/common/kernel/nextpnr.cc
new file mode 100644
index 00000000..8c902d88
--- /dev/null
+++ b/common/kernel/nextpnr.cc
@@ -0,0 +1,35 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#if defined(__wasm)
+#include <exception>
+#include <typeinfo>
+#include "log.h"
+
+extern "C" {
+// FIXME: WASI does not currently support exceptions.
+void *__cxa_allocate_exception(size_t thrown_size) throw() { return malloc(thrown_size); }
+bool __cxa_uncaught_exception() throw();
+void __cxa_throw(void *thrown_exception, struct std::type_info *tinfo, void (*dest)(void *)) { std::terminate(); }
+}
+
+namespace boost {
+void throw_exception(std::exception const &e) { NEXTPNR_NAMESPACE::log_error("boost::exception(): %s\n", e.what()); }
+} // namespace boost
+#endif
diff --git a/common/kernel/nextpnr.h b/common/kernel/nextpnr.h
new file mode 100644
index 00000000..3b65900b
--- /dev/null
+++ b/common/kernel/nextpnr.h
@@ -0,0 +1,29 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+#ifndef NEXTPNR_H
+#define NEXTPNR_H
+
+#include "base_arch.h"
+#include "context.h"
+#include "nextpnr_assertions.h"
+#include "nextpnr_namespaces.h"
+#include "nextpnr_types.h"
+
+#endif
diff --git a/common/kernel/nextpnr_assertions.cc b/common/kernel/nextpnr_assertions.cc
new file mode 100644
index 00000000..ac4cdf57
--- /dev/null
+++ b/common/kernel/nextpnr_assertions.cc
@@ -0,0 +1,33 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "nextpnr_assertions.h"
+#include "log.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+assertion_failure::assertion_failure(std::string msg, std::string expr_str, std::string filename, int line)
+        : runtime_error("Assertion failure: " + msg + " (" + filename + ":" + std::to_string(line) + ")"), msg(msg),
+          expr_str(expr_str), filename(filename), line(line)
+{
+    log_flush();
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/nextpnr_assertions.h b/common/kernel/nextpnr_assertions.h
new file mode 100644
index 00000000..1989aa3a
--- /dev/null
+++ b/common/kernel/nextpnr_assertions.h
@@ -0,0 +1,64 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef NEXTPNR_ASSERTIONS_H
+#define NEXTPNR_ASSERTIONS_H
+
+#include <stdexcept>
+#include <string>
+
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+class assertion_failure : public std::runtime_error
+{
+  public:
+    assertion_failure(std::string msg, std::string expr_str, std::string filename, int line);
+
+    std::string msg;
+    std::string expr_str;
+    std::string filename;
+    int line;
+};
+
+NPNR_NORETURN
+inline void assert_fail_impl(const char *message, const char *expr_str, const char *filename, int line)
+{
+    throw assertion_failure(message, expr_str, filename, line);
+}
+
+NPNR_NORETURN
+inline void assert_fail_impl_str(std::string message, const char *expr_str, const char *filename, int line)
+{
+    throw assertion_failure(message, expr_str, filename, line);
+}
+
+#define NPNR_ASSERT(cond) (!(cond) ? assert_fail_impl(#cond, #cond, __FILE__, __LINE__) : (void)true)
+#define NPNR_ASSERT_MSG(cond, msg) (!(cond) ? assert_fail_impl(msg, #cond, __FILE__, __LINE__) : (void)true)
+#define NPNR_ASSERT_FALSE(msg) (assert_fail_impl(msg, "false", __FILE__, __LINE__))
+#define NPNR_ASSERT_FALSE_STR(msg) (assert_fail_impl_str(msg, "false", __FILE__, __LINE__))
+
+#define NPNR_STRINGIFY_MACRO(x) NPNR_STRINGIFY(x)
+#define NPNR_STRINGIFY(x) #x
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* NEXTPNR_ASSERTIONS_H */
diff --git a/common/kernel/nextpnr_base_types.h b/common/kernel/nextpnr_base_types.h
new file mode 100644
index 00000000..944bf0b8
--- /dev/null
+++ b/common/kernel/nextpnr_base_types.h
@@ -0,0 +1,135 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+// Theses are the nextpnr types that do **not** depend on user defined types,
+// like BelId, etc.
+//
+// If a common type is required that depends on one of the user defined types,
+// add it to nextpnr_types.h, which includes "archdefs.h", or make a new
+// header that includes "archdefs.h"
+#ifndef NEXTPNR_BASE_TYPES_H
+#define NEXTPNR_BASE_TYPES_H
+
+#include <boost/functional/hash.hpp>
+#include <string>
+
+#include "hashlib.h"
+#include "idstring.h"
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct GraphicElement
+{
+    enum type_t
+    {
+        TYPE_NONE,
+        TYPE_LINE,
+        TYPE_ARROW,
+        TYPE_BOX,
+        TYPE_CIRCLE,
+        TYPE_LABEL,
+        TYPE_LOCAL_ARROW, // Located entirely within the cell boundaries, coordinates in the range [0., 1.]
+        TYPE_LOCAL_LINE,
+
+        TYPE_MAX
+    } type = TYPE_NONE;
+
+    enum style_t
+    {
+        STYLE_GRID,
+        STYLE_FRAME,    // Static "frame". Contrast between STYLE_INACTIVE and STYLE_ACTIVE
+        STYLE_HIDDEN,   // Only display when object is selected or highlighted
+        STYLE_INACTIVE, // Render using low-contrast color
+        STYLE_ACTIVE,   // Render using high-contast color
+
+        // UI highlight groups
+        STYLE_HIGHLIGHTED0,
+        STYLE_HIGHLIGHTED1,
+        STYLE_HIGHLIGHTED2,
+        STYLE_HIGHLIGHTED3,
+        STYLE_HIGHLIGHTED4,
+        STYLE_HIGHLIGHTED5,
+        STYLE_HIGHLIGHTED6,
+        STYLE_HIGHLIGHTED7,
+
+        STYLE_SELECTED,
+        STYLE_HOVER,
+
+        STYLE_MAX
+    } style = STYLE_FRAME;
+
+    float x1 = 0, y1 = 0, x2 = 0, y2 = 0, z = 0;
+    std::string text;
+    GraphicElement(){};
+    GraphicElement(type_t type, style_t style, float x1, float y1, float x2, float y2, float z)
+            : type(type), style(style), x1(x1), y1(y1), x2(x2), y2(y2), z(z){};
+};
+
+struct Loc
+{
+    int x = -1, y = -1, z = -1;
+
+    Loc() {}
+    Loc(int x, int y, int z) : x(x), y(y), z(z) {}
+
+    bool operator==(const Loc &other) const { return (x == other.x) && (y == other.y) && (z == other.z); }
+    bool operator!=(const Loc &other) const { return (x != other.x) || (y != other.y) || (z != other.z); }
+    unsigned int hash() const { return mkhash(x, mkhash(y, z)); }
+};
+
+struct ArcBounds
+{
+    int x0 = -1, y0 = -1, x1 = -1, y1 = -1;
+
+    ArcBounds() {}
+    ArcBounds(int x0, int y0, int x1, int y1) : x0(x0), y0(y0), x1(x1), y1(y1){};
+
+    int distance(Loc loc) const
+    {
+        int dist = 0;
+        if (loc.x < x0)
+            dist += x0 - loc.x;
+        if (loc.x > x1)
+            dist += loc.x - x1;
+        if (loc.y < y0)
+            dist += y0 - loc.y;
+        if (loc.y > y1)
+            dist += loc.y - y1;
+        return dist;
+    };
+
+    bool contains(int x, int y) const { return x >= x0 && y >= y0 && x <= x1 && y <= y1; }
+};
+
+enum PlaceStrength
+{
+    STRENGTH_NONE = 0,
+    STRENGTH_WEAK = 1,
+    STRENGTH_STRONG = 2,
+    STRENGTH_PLACER = 3,
+    STRENGTH_FIXED = 4,
+    STRENGTH_LOCKED = 5,
+    STRENGTH_USER = 6
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* NEXTPNR_BASE_TYPES_H */
diff --git a/common/kernel/nextpnr_namespaces.cc b/common/kernel/nextpnr_namespaces.cc
new file mode 100644
index 00000000..802c89b4
--- /dev/null
+++ b/common/kernel/nextpnr_namespaces.cc
@@ -0,0 +1,23 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+// This cc file exists to ensure that "nextpnr_namespaces.h" can be compiled
+// on its own.
+#include "nextpnr_namespaces.h"
diff --git a/common/kernel/nextpnr_namespaces.h b/common/kernel/nextpnr_namespaces.h
new file mode 100644
index 00000000..b758d7c5
--- /dev/null
+++ b/common/kernel/nextpnr_namespaces.h
@@ -0,0 +1,58 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef NEXTPNR_NAMESPACES_H
+#define NEXTPNR_NAMESPACES_H
+
+#ifdef NEXTPNR_NAMESPACE
+#define NEXTPNR_NAMESPACE_PREFIX NEXTPNR_NAMESPACE::
+#define NEXTPNR_NAMESPACE_BEGIN namespace NEXTPNR_NAMESPACE {
+#define NEXTPNR_NAMESPACE_END }
+#define USING_NEXTPNR_NAMESPACE using namespace NEXTPNR_NAMESPACE;
+#else
+#define NEXTPNR_NAMESPACE_PREFIX
+#define NEXTPNR_NAMESPACE_BEGIN
+#define NEXTPNR_NAMESPACE_END
+#define USING_NEXTPNR_NAMESPACE
+#endif
+
+#define NPNR_UNUSED(x) ((void)x)
+
+#if defined(__GNUC__) || defined(__clang__)
+#define NPNR_ATTRIBUTE(...) __attribute__((__VA_ARGS__))
+#define NPNR_NORETURN __attribute__((noreturn))
+#define NPNR_DEPRECATED __attribute__((deprecated))
+#define NPNR_PACKED_STRUCT(...) __VA_ARGS__ __attribute__((packed))
+#define NPNR_ALWAYS_INLINE NPNR_ATTRIBUTE(__always_inline__)
+#elif defined(_MSC_VER)
+#define NPNR_ATTRIBUTE(...)
+#define NPNR_NORETURN __declspec(noreturn)
+#define NPNR_DEPRECATED __declspec(deprecated)
+#define NPNR_PACKED_STRUCT(...) __pragma(pack(push, 1)) __VA_ARGS__ __pragma(pack(pop))
+#define NPNR_ALWAYS_INLINE
+#else
+#define NPNR_ATTRIBUTE(...)
+#define NPNR_NORETURN
+#define NPNR_DEPRECATED
+#define NPNR_PACKED_STRUCT(...) __VA_ARGS__
+#define NPNR_ALWAYS_INLINE
+#endif
+
+#endif /* NEXTPNR_NAMESPACES_H */
diff --git a/common/kernel/nextpnr_types.cc b/common/kernel/nextpnr_types.cc
new file mode 100644
index 00000000..57d816c0
--- /dev/null
+++ b/common/kernel/nextpnr_types.cc
@@ -0,0 +1,180 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "nextpnr_types.h"
+#include "context.h"
+#include "log.h"
+
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+void CellInfo::addInput(IdString name)
+{
+    ports[name].name = name;
+    ports[name].type = PORT_IN;
+}
+void CellInfo::addOutput(IdString name)
+{
+    ports[name].name = name;
+    ports[name].type = PORT_OUT;
+}
+void CellInfo::addInout(IdString name)
+{
+    ports[name].name = name;
+    ports[name].type = PORT_INOUT;
+}
+
+void CellInfo::setParam(IdString name, Property value) { params[name] = value; }
+void CellInfo::unsetParam(IdString name) { params.erase(name); }
+void CellInfo::setAttr(IdString name, Property value) { attrs[name] = value; }
+void CellInfo::unsetAttr(IdString name) { attrs.erase(name); }
+
+bool CellInfo::testRegion(BelId bel) const
+{
+    return region == nullptr || !region->constr_bels || region->bels.count(bel);
+}
+
+void CellInfo::connectPort(IdString port_name, NetInfo *net)
+{
+    if (net == nullptr)
+        return;
+    PortInfo &port = ports.at(port_name);
+    NPNR_ASSERT(port.net == nullptr);
+    port.net = net;
+    if (port.type == PORT_OUT) {
+        NPNR_ASSERT(net->driver.cell == nullptr);
+        net->driver.cell = this;
+        net->driver.port = port_name;
+    } else if (port.type == PORT_IN || port.type == PORT_INOUT) {
+        PortRef user;
+        user.cell = this;
+        user.port = port_name;
+        port.user_idx = net->users.add(user);
+    } else {
+        NPNR_ASSERT_FALSE("invalid port type for connect_port");
+    }
+}
+
+void CellInfo::disconnectPort(IdString port_name)
+{
+    if (!ports.count(port_name))
+        return;
+    PortInfo &port = ports.at(port_name);
+    if (port.net != nullptr) {
+        if (port.user_idx)
+            port.net->users.remove(port.user_idx);
+        if (port.net->driver.cell == this && port.net->driver.port == port_name)
+            port.net->driver.cell = nullptr;
+        port.net = nullptr;
+    }
+}
+
+void CellInfo::connectPorts(IdString port, CellInfo *other, IdString other_port)
+{
+    PortInfo &port1 = ports.at(port);
+    if (port1.net == nullptr) {
+        // No net on port1; need to create one
+        NetInfo *p1net = ctx->createNet(ctx->id(name.str(ctx) + "$conn$" + port.str(ctx)));
+        connectPort(port, p1net);
+    }
+    other->connectPort(other_port, port1.net);
+}
+
+void CellInfo::movePortTo(IdString port, CellInfo *other, IdString other_port)
+{
+    if (!ports.count(port))
+        return;
+    PortInfo &old = ports.at(port);
+
+    // Create port on the replacement cell if it doesn't already exist
+    if (!other->ports.count(other_port)) {
+        other->ports[other_port].name = other_port;
+        other->ports[other_port].type = old.type;
+    }
+
+    PortInfo &rep = other->ports.at(other_port);
+    NPNR_ASSERT(old.type == rep.type);
+
+    rep.net = old.net;
+    rep.user_idx = old.user_idx;
+    old.net = nullptr;
+    old.user_idx = store_index<PortRef>{};
+    if (rep.type == PORT_OUT) {
+        if (rep.net != nullptr) {
+            rep.net->driver.cell = other;
+            rep.net->driver.port = other_port;
+        }
+    } else if (rep.type == PORT_IN) {
+        if (rep.net != nullptr) {
+            auto &load = rep.net->users.at(rep.user_idx);
+            load.cell = other;
+            load.port = other_port;
+        }
+    } else {
+        NPNR_ASSERT(false);
+    }
+}
+
+void CellInfo::renamePort(IdString old_name, IdString new_name)
+{
+    if (!ports.count(old_name))
+        return;
+    PortInfo pi = ports.at(old_name);
+    if (pi.net != nullptr) {
+        if (pi.net->driver.cell == this && pi.net->driver.port == old_name)
+            pi.net->driver.port = new_name;
+        if (pi.user_idx)
+            pi.net->users.at(pi.user_idx).port = new_name;
+    }
+    ports.erase(old_name);
+    pi.name = new_name;
+    ports[new_name] = pi;
+}
+
+void CellInfo::movePortBusTo(IdString old_name, int old_offset, bool old_brackets, CellInfo *new_cell,
+                             IdString new_name, int new_offset, bool new_brackets, int width)
+{
+    for (int i = 0; i < width; i++) {
+        IdString old_port = ctx->id(stringf(old_brackets ? "%s[%d]" : "%s%d", old_name.c_str(ctx), i + old_offset));
+        IdString new_port = ctx->id(stringf(new_brackets ? "%s[%d]" : "%s%d", new_name.c_str(ctx), i + new_offset));
+        movePortTo(old_port, new_cell, new_port);
+    }
+}
+
+void CellInfo::copyPortTo(IdString port, CellInfo *other, IdString other_port)
+{
+    if (!ports.count(port))
+        return;
+    other->ports[other_port].name = other_port;
+    other->ports[other_port].type = ports.at(port).type;
+    other->connectPort(other_port, ports.at(port).net);
+}
+
+void CellInfo::copyPortBusTo(IdString old_name, int old_offset, bool old_brackets, CellInfo *new_cell,
+                             IdString new_name, int new_offset, bool new_brackets, int width)
+{
+    for (int i = 0; i < width; i++) {
+        IdString old_port = ctx->id(stringf(old_brackets ? "%s[%d]" : "%s%d", old_name.c_str(ctx), i + old_offset));
+        IdString new_port = ctx->id(stringf(new_brackets ? "%s[%d]" : "%s%d", new_name.c_str(ctx), i + new_offset));
+        copyPortTo(old_port, new_cell, new_port);
+    }
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/nextpnr_types.h b/common/kernel/nextpnr_types.h
new file mode 100644
index 00000000..c21182cc
--- /dev/null
+++ b/common/kernel/nextpnr_types.h
@@ -0,0 +1,364 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+// Types defined in this header use one or more user defined types (e.g. BelId).
+// If a new common type is desired that doesn't depend on a user defined type,
+// either put it in it's own header, or in nextpnr_base_types.h.
+#ifndef NEXTPNR_TYPES_H
+#define NEXTPNR_TYPES_H
+
+#include <unordered_map>
+#include <unordered_set>
+
+#include "archdefs.h"
+#include "hashlib.h"
+#include "indexed_store.h"
+#include "nextpnr_base_types.h"
+#include "nextpnr_namespaces.h"
+#include "property.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct DecalXY
+{
+    DecalId decal;
+    float x = 0, y = 0;
+
+    bool operator==(const DecalXY &other) const { return (decal == other.decal && x == other.x && y == other.y); }
+};
+
+struct BelPin
+{
+    BelId bel;
+    IdString pin;
+};
+
+struct Region
+{
+    IdString name;
+
+    bool constr_bels = false;
+    bool constr_wires = false;
+    bool constr_pips = false;
+
+    pool<BelId> bels;
+    pool<WireId> wires;
+    pool<Loc> piplocs;
+};
+
+struct PipMap
+{
+    PipId pip = PipId();
+    PlaceStrength strength = STRENGTH_NONE;
+};
+
+struct CellInfo;
+
+struct PortRef
+{
+    CellInfo *cell = nullptr;
+    IdString port;
+    delay_t budget = 0;
+};
+
+// minimum and maximum delay
+struct DelayPair
+{
+    DelayPair(){};
+    explicit DelayPair(delay_t delay) : min_delay(delay), max_delay(delay){};
+    DelayPair(delay_t min_delay, delay_t max_delay) : min_delay(min_delay), max_delay(max_delay){};
+    delay_t minDelay() const { return min_delay; };
+    delay_t maxDelay() const { return max_delay; };
+    delay_t min_delay, max_delay;
+    DelayPair operator+(const DelayPair &other) const
+    {
+        return {min_delay + other.min_delay, max_delay + other.max_delay};
+    }
+    DelayPair operator-(const DelayPair &other) const
+    {
+        return {min_delay - other.min_delay, max_delay - other.max_delay};
+    }
+};
+
+// four-quadrant, min and max rise and fall delay
+struct DelayQuad
+{
+    DelayPair rise, fall;
+    DelayQuad(){};
+    explicit DelayQuad(delay_t delay) : rise(delay), fall(delay){};
+    DelayQuad(delay_t min_delay, delay_t max_delay) : rise(min_delay, max_delay), fall(min_delay, max_delay){};
+    DelayQuad(DelayPair rise, DelayPair fall) : rise(rise), fall(fall){};
+    DelayQuad(delay_t min_rise, delay_t max_rise, delay_t min_fall, delay_t max_fall)
+            : rise(min_rise, max_rise), fall(min_fall, max_fall){};
+
+    delay_t minRiseDelay() const { return rise.minDelay(); };
+    delay_t maxRiseDelay() const { return rise.maxDelay(); };
+    delay_t minFallDelay() const { return fall.minDelay(); };
+    delay_t maxFallDelay() const { return fall.maxDelay(); };
+    delay_t minDelay() const { return std::min<delay_t>(rise.minDelay(), fall.minDelay()); };
+    delay_t maxDelay() const { return std::max<delay_t>(rise.maxDelay(), fall.maxDelay()); };
+
+    DelayPair delayPair() const { return DelayPair(minDelay(), maxDelay()); };
+
+    DelayQuad operator+(const DelayQuad &other) const { return {rise + other.rise, fall + other.fall}; }
+    DelayQuad operator-(const DelayQuad &other) const { return {rise - other.rise, fall - other.fall}; }
+};
+
+struct ClockConstraint;
+
+struct NetInfo : ArchNetInfo
+{
+    explicit NetInfo(IdString name) : name(name){};
+    IdString name, hierpath;
+    int32_t udata = 0;
+
+    PortRef driver;
+    indexed_store<PortRef> users;
+    dict<IdString, Property> attrs;
+
+    // wire -> uphill_pip
+    dict<WireId, PipMap> wires;
+
+    std::vector<IdString> aliases; // entries in net_aliases that point to this net
+
+    std::unique_ptr<ClockConstraint> clkconstr;
+
+    Region *region = nullptr;
+};
+
+enum PortType
+{
+    PORT_IN = 0,
+    PORT_OUT = 1,
+    PORT_INOUT = 2
+};
+
+struct PortInfo
+{
+    IdString name;
+    NetInfo *net;
+    PortType type;
+    store_index<PortRef> user_idx{};
+};
+
+struct Context;
+
+struct CellInfo : ArchCellInfo
+{
+    CellInfo(Context *ctx, IdString name, IdString type) : ctx(ctx), name(name), type(type){};
+    Context *ctx = nullptr;
+
+    IdString name, type, hierpath;
+    int32_t udata;
+
+    dict<IdString, PortInfo> ports;
+    dict<IdString, Property> attrs, params;
+
+    BelId bel;
+    PlaceStrength belStrength = STRENGTH_NONE;
+
+    // cell is part of a cluster if != ClusterId
+    ClusterId cluster;
+
+    Region *region = nullptr;
+
+    void addInput(IdString name);
+    void addOutput(IdString name);
+    void addInout(IdString name);
+
+    void setParam(IdString name, Property value);
+    void unsetParam(IdString name);
+    void setAttr(IdString name, Property value);
+    void unsetAttr(IdString name);
+    // check whether a bel complies with the cell's region constraint
+    bool testRegion(BelId bel) const;
+
+    NetInfo *getPort(IdString name)
+    {
+        auto found = ports.find(name);
+        return (found == ports.end()) ? nullptr : found->second.net;
+    }
+    const NetInfo *getPort(IdString name) const
+    {
+        auto found = ports.find(name);
+        return (found == ports.end()) ? nullptr : found->second.net;
+    }
+    void connectPort(IdString port, NetInfo *net);
+    void disconnectPort(IdString port);
+    void connectPorts(IdString port, CellInfo *other, IdString other_port);
+    void movePortTo(IdString port, CellInfo *other, IdString other_port);
+    void renamePort(IdString old_name, IdString new_name);
+    void movePortBusTo(IdString old_name, int old_offset, bool old_brackets, CellInfo *new_cell, IdString new_name,
+                       int new_offset, bool new_brackets, int width);
+    void copyPortTo(IdString port, CellInfo *other, IdString other_port);
+    void copyPortBusTo(IdString old_name, int old_offset, bool old_brackets, CellInfo *new_cell, IdString new_name,
+                       int new_offset, bool new_brackets, int width);
+};
+
+enum TimingPortClass
+{
+    TMG_CLOCK_INPUT,     // Clock input to a sequential cell
+    TMG_GEN_CLOCK,       // Generated clock output (PLL, DCC, etc)
+    TMG_REGISTER_INPUT,  // Input to a register, with an associated clock (may also have comb. fanout too)
+    TMG_REGISTER_OUTPUT, // Output from a register
+    TMG_COMB_INPUT,      // Combinational input, no paths end here
+    TMG_COMB_OUTPUT,     // Combinational output, no paths start here
+    TMG_STARTPOINT,      // Unclocked primary startpoint, such as an IO cell output
+    TMG_ENDPOINT,        // Unclocked primary endpoint, such as an IO cell input
+    TMG_IGNORE,          // Asynchronous to all clocks, "don't care", and should be ignored (false path) for analysis
+};
+
+enum ClockEdge
+{
+    RISING_EDGE,
+    FALLING_EDGE
+};
+
+struct TimingClockingInfo
+{
+    IdString clock_port; // Port name of clock domain
+    ClockEdge edge;
+    DelayPair setup, hold; // Input timing checks
+    DelayQuad clockToQ;    // Output clock-to-Q time
+};
+
+struct ClockConstraint
+{
+    DelayPair high;
+    DelayPair low;
+    DelayPair period;
+};
+
+struct ClockFmax
+{
+    float achieved;
+    float constraint;
+};
+
+struct ClockEvent
+{
+    IdString clock;
+    ClockEdge edge;
+
+    bool operator==(const ClockEvent &other) const { return clock == other.clock && edge == other.edge; }
+    unsigned int hash() const { return mkhash(clock.hash(), int(edge)); }
+};
+
+struct ClockPair
+{
+    ClockEvent start, end;
+
+    bool operator==(const ClockPair &other) const { return start == other.start && end == other.end; }
+    unsigned int hash() const { return mkhash(start.hash(), end.hash()); }
+};
+
+struct CriticalPath
+{
+    struct Segment
+    {
+
+        // Segment type
+        enum class Type
+        {
+            CLK_TO_Q, // Clock-to-Q delay
+            SOURCE,   // Delayless source
+            LOGIC,    // Combinational logic delay
+            ROUTING,  // Routing delay
+            SETUP     // Setup time in sink
+        };
+
+        // Type
+        Type type;
+        // Net name (routing only)
+        IdString net;
+        // From cell.port
+        std::pair<IdString, IdString> from;
+        // To cell.port
+        std::pair<IdString, IdString> to;
+        // Segment delay
+        delay_t delay;
+        // Segment budget (routing only)
+        delay_t budget;
+    };
+
+    // Clock pair
+    ClockPair clock_pair;
+    // Total path delay
+    delay_t delay;
+    // Period (max allowed delay)
+    delay_t period;
+    // Individual path segments
+    std::vector<Segment> segments;
+};
+
+// Holds timing information of a single source to sink path of a net
+struct NetSinkTiming
+{
+    // Clock event pair
+    ClockPair clock_pair;
+    // Cell and port (the sink)
+    std::pair<IdString, IdString> cell_port;
+    // Delay
+    delay_t delay;
+    // Delay budget
+    delay_t budget;
+};
+
+struct TimingResult
+{
+    // Achieved and target Fmax for all clock domains
+    dict<IdString, ClockFmax> clock_fmax;
+    // Single domain critical paths
+    dict<IdString, CriticalPath> clock_paths;
+    // Cross-domain critical paths
+    std::vector<CriticalPath> xclock_paths;
+
+    // Detailed net timing data
+    dict<IdString, std::vector<NetSinkTiming>> detailed_net_timings;
+};
+
+// Represents the contents of a non-leaf cell in a design
+// with hierarchy
+
+struct HierarchicalPort
+{
+    IdString name;
+    PortType dir;
+    std::vector<IdString> nets;
+    int offset;
+    bool upto;
+};
+
+struct HierarchicalCell
+{
+    IdString name, type, parent, fullpath;
+    // Name inside cell instance -> global name
+    dict<IdString, IdString> leaf_cells, nets;
+    // Global name -> name inside cell instance
+    dict<IdString, IdString> leaf_cells_by_gname, nets_by_gname;
+    // Cell port to net
+    dict<IdString, HierarchicalPort> ports;
+    // Name inside cell instance -> global name
+    dict<IdString, IdString> hier_cells;
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* NEXTPNR_TYPES_H */
diff --git a/common/kernel/property.cc b/common/kernel/property.cc
new file mode 100644
index 00000000..6c30436d
--- /dev/null
+++ b/common/kernel/property.cc
@@ -0,0 +1,80 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "property.h"
+
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+Property::Property() : is_string(false), str(""), intval(0) {}
+
+Property::Property(int64_t intval, int width) : is_string(false), intval(intval)
+{
+    str.reserve(width);
+    for (int i = 0; i < width; i++)
+        str.push_back((intval & (1ULL << i)) ? S1 : S0);
+}
+
+Property::Property(const std::string &strval) : is_string(true), str(strval), intval(0xDEADBEEF) {}
+
+Property::Property(State bit) : is_string(false), str(std::string("") + char(bit)), intval(bit == S1) {}
+
+std::string Property::to_string() const
+{
+    if (is_string) {
+        std::string result = str;
+        int state = 0;
+        for (char c : str) {
+            if (state == 0) {
+                if (c == '0' || c == '1' || c == 'x' || c == 'z')
+                    state = 0;
+                else if (c == ' ')
+                    state = 1;
+                else
+                    state = 2;
+            } else if (state == 1 && c != ' ')
+                state = 2;
+        }
+        if (state < 2)
+            result += " ";
+        return result;
+    } else {
+        return std::string(str.rbegin(), str.rend());
+    }
+}
+
+Property Property::from_string(const std::string &s)
+{
+    Property p;
+
+    size_t cursor = s.find_first_not_of("01xz");
+    if (cursor == std::string::npos) {
+        p.str = std::string(s.rbegin(), s.rend());
+        p.is_string = false;
+        p.update_intval();
+    } else if (s.find_first_not_of(' ', cursor) == std::string::npos) {
+        p = Property(s.substr(0, s.size() - 1));
+    } else {
+        p = Property(s);
+    }
+    return p;
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/property.h b/common/kernel/property.h
new file mode 100644
index 00000000..814b2cac
--- /dev/null
+++ b/common/kernel/property.h
@@ -0,0 +1,131 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef PROPERTY_H
+#define PROPERTY_H
+
+#include <algorithm>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+#include "nextpnr_assertions.h"
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct Property
+{
+    enum State : char
+    {
+        S0 = '0',
+        S1 = '1',
+        Sx = 'x',
+        Sz = 'z'
+    };
+
+    Property();
+    Property(int64_t intval, int width = 32);
+    Property(const std::string &strval);
+    Property(State bit);
+    Property &operator=(const Property &other) = default;
+
+    bool is_string;
+
+    // The string literal (for string values), or a string of [01xz] (for numeric values)
+    std::string str;
+    // The lower 64 bits (for numeric values), unused for string values
+    int64_t intval;
+
+    void update_intval()
+    {
+        intval = 0;
+        for (int i = 0; i < int(str.size()); i++) {
+            NPNR_ASSERT(str[i] == S0 || str[i] == S1 || str[i] == Sx || str[i] == Sz);
+            if ((str[i] == S1) && i < 64)
+                intval |= (1ULL << i);
+        }
+    }
+
+    int64_t as_int64() const
+    {
+        NPNR_ASSERT(!is_string);
+        return intval;
+    }
+    std::vector<bool> as_bits() const
+    {
+        std::vector<bool> result;
+        result.reserve(str.size());
+        NPNR_ASSERT(!is_string);
+        for (auto c : str)
+            result.push_back(c == S1);
+        return result;
+    }
+    const std::string &as_string() const
+    {
+        NPNR_ASSERT(is_string);
+        return str;
+    }
+    const char *c_str() const
+    {
+        NPNR_ASSERT(is_string);
+        return str.c_str();
+    }
+    size_t size() const { return is_string ? 8 * str.size() : str.size(); }
+    double as_double() const
+    {
+        NPNR_ASSERT(is_string);
+        return std::stod(str);
+    }
+    bool as_bool() const
+    {
+        if (int(str.size()) <= 64)
+            return intval != 0;
+        else
+            return std::any_of(str.begin(), str.end(), [](char c) { return c == S1; });
+    }
+    bool is_fully_def() const
+    {
+        return !is_string && std::all_of(str.begin(), str.end(), [](char c) { return c == S0 || c == S1; });
+    }
+    Property extract(int offset, int len, State padding = State::S0) const
+    {
+        Property ret;
+        ret.is_string = false;
+        ret.str.reserve(len);
+        for (int i = offset; i < offset + len; i++)
+            ret.str.push_back(i < int(str.size()) ? str[i] : char(padding));
+        ret.update_intval();
+        return ret;
+    }
+    // Convert to a string representation, escaping literal strings matching /^[01xz]* *$/ by adding a space at the end,
+    // to disambiguate from binary strings
+    std::string to_string() const;
+    // Convert a string of four-value binary [01xz], or a literal string escaped according to the above rule
+    // to a Property
+    static Property from_string(const std::string &s);
+};
+
+inline bool operator==(const Property &a, const Property &b) { return a.is_string == b.is_string && a.str == b.str; }
+inline bool operator!=(const Property &a, const Property &b) { return a.is_string != b.is_string || a.str != b.str; }
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* PROPERTY_H */
diff --git a/common/kernel/pybindings.cc b/common/kernel/pybindings.cc
new file mode 100644
index 00000000..9a783eb4
--- /dev/null
+++ b/common/kernel/pybindings.cc
@@ -0,0 +1,362 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef NO_PYTHON
+
+#include "pybindings.h"
+#include "arch_pybindings.h"
+#include "json_frontend.h"
+#include "log.h"
+#include "nextpnr.h"
+
+#include <fstream>
+#include <memory>
+#include <signal.h>
+NEXTPNR_NAMESPACE_BEGIN
+
+// Required to determine concatenated module name (which differs for different
+// archs)
+#define PASTER(x, y) x##_##y
+#define EVALUATOR(x, y) PASTER(x, y)
+#define MODULE_NAME EVALUATOR(nextpnrpy, ARCHNAME)
+#define PYINIT_MODULE_NAME EVALUATOR(&PyInit_nextpnrpy, ARCHNAME)
+#define STRINGIFY(x) #x
+#define TOSTRING(x) STRINGIFY(x)
+
+// Architecture-specific bindings should be created in the below function, which
+// must be implemented in all architectures
+void arch_wrap_python(py::module &m);
+
+bool operator==(const PortRef &a, const PortRef &b) { return (a.cell == b.cell) && (a.port == b.port); }
+
+// Load a JSON file into a design
+void parse_json_shim(std::string filename, Context &d)
+{
+    std::ifstream inf(filename);
+    if (!inf)
+        throw std::runtime_error("failed to open file " + filename);
+    parse_json(inf, filename, &d);
+}
+
+// Create a new Chip and load design from json file
+Context *load_design_shim(std::string filename, ArchArgs args)
+{
+    Context *d = new Context(args);
+    parse_json_shim(filename, *d);
+    return d;
+}
+
+namespace PythonConversion {
+template <> struct string_converter<PortRef &>
+{
+    inline PortRef from_str(Context *ctx, std::string name) { NPNR_ASSERT_FALSE("PortRef from_str not implemented"); }
+
+    inline std::string to_str(Context *ctx, const PortRef &pr)
+    {
+        return pr.cell->name.str(ctx) + "." + pr.port.str(ctx);
+    }
+};
+
+template <> struct string_converter<Property>
+{
+    inline Property from_str(Context *ctx, std::string s) { return Property::from_string(s); }
+
+    inline std::string to_str(Context *ctx, Property p) { return p.to_string(); }
+};
+
+} // namespace PythonConversion
+
+std::string loc_repr_py(Loc loc) { return stringf("Loc(%d, %d, %d)", loc.x, loc.y, loc.z); }
+
+PYBIND11_EMBEDDED_MODULE(MODULE_NAME, m)
+{
+    py::register_exception_translator([](std::exception_ptr p) {
+        try {
+            if (p)
+                std::rethrow_exception(p);
+        } catch (const assertion_failure &e) {
+            PyErr_SetString(PyExc_AssertionError, e.what());
+        }
+    });
+
+    using namespace PythonConversion;
+
+    py::enum_<GraphicElement::type_t>(m, "GraphicElementType")
+            .value("TYPE_NONE", GraphicElement::TYPE_NONE)
+            .value("TYPE_LINE", GraphicElement::TYPE_LINE)
+            .value("TYPE_ARROW", GraphicElement::TYPE_ARROW)
+            .value("TYPE_BOX", GraphicElement::TYPE_BOX)
+            .value("TYPE_CIRCLE", GraphicElement::TYPE_CIRCLE)
+            .value("TYPE_LABEL", GraphicElement::TYPE_LABEL)
+            .export_values();
+
+    py::enum_<GraphicElement::style_t>(m, "GraphicElementStyle")
+            .value("STYLE_GRID", GraphicElement::STYLE_GRID)
+            .value("STYLE_FRAME", GraphicElement::STYLE_FRAME)
+            .value("STYLE_HIDDEN", GraphicElement::STYLE_HIDDEN)
+            .value("STYLE_INACTIVE", GraphicElement::STYLE_INACTIVE)
+            .value("STYLE_ACTIVE", GraphicElement::STYLE_ACTIVE)
+            .export_values();
+
+    py::class_<GraphicElement>(m, "GraphicElement")
+            .def(py::init<GraphicElement::type_t, GraphicElement::style_t, float, float, float, float, float>(),
+                 py::arg("type"), py::arg("style"), py::arg("x1"), py::arg("y1"), py::arg("x2"), py::arg("y2"),
+                 py::arg("z"))
+            .def_readwrite("type", &GraphicElement::type)
+            .def_readwrite("x1", &GraphicElement::x1)
+            .def_readwrite("y1", &GraphicElement::y1)
+            .def_readwrite("x2", &GraphicElement::x2)
+            .def_readwrite("y2", &GraphicElement::y2)
+            .def_readwrite("text", &GraphicElement::text);
+
+    py::enum_<PortType>(m, "PortType")
+            .value("PORT_IN", PORT_IN)
+            .value("PORT_OUT", PORT_OUT)
+            .value("PORT_INOUT", PORT_INOUT)
+            .export_values();
+
+    py::enum_<PlaceStrength>(m, "PlaceStrength")
+            .value("STRENGTH_NONE", STRENGTH_NONE)
+            .value("STRENGTH_WEAK", STRENGTH_WEAK)
+            .value("STRENGTH_STRONG", STRENGTH_STRONG)
+            .value("STRENGTH_FIXED", STRENGTH_FIXED)
+            .value("STRENGTH_LOCKED", STRENGTH_LOCKED)
+            .value("STRENGTH_USER", STRENGTH_USER)
+            .export_values();
+
+    py::class_<DelayPair>(m, "DelayPair")
+            .def(py::init<>())
+            .def(py::init<delay_t>())
+            .def(py::init<delay_t, delay_t>())
+            .def_readwrite("min_delay", &DelayPair::min_delay)
+            .def_readwrite("max_delay", &DelayPair::max_delay)
+            .def("minDelay", &DelayPair::minDelay)
+            .def("maxDelay", &DelayPair::maxDelay);
+
+    py::class_<DelayQuad>(m, "DelayQuad")
+            .def(py::init<>())
+            .def(py::init<delay_t>())
+            .def(py::init<delay_t, delay_t>())
+            .def(py::init<delay_t, delay_t, delay_t, delay_t>())
+            .def(py::init<DelayPair, DelayPair>())
+            .def_readwrite("rise", &DelayQuad::rise)
+            .def_readwrite("fall", &DelayQuad::fall)
+            .def("minDelay", &DelayQuad::minDelay)
+            .def("minRiseDelay", &DelayQuad::minRiseDelay)
+            .def("minFallDelay", &DelayQuad::minFallDelay)
+            .def("maxDelay", &DelayQuad::maxDelay)
+            .def("maxRiseDelay", &DelayQuad::maxRiseDelay)
+            .def("maxFallDelay", &DelayQuad::maxFallDelay)
+            .def("delayPair", &DelayQuad::delayPair);
+
+    typedef dict<IdString, Property> AttrMap;
+    typedef dict<IdString, PortInfo> PortMap;
+    typedef dict<IdString, IdString> IdIdMap;
+    typedef dict<IdString, std::unique_ptr<Region>> RegionMap;
+
+    py::class_<BaseCtx>(m, "BaseCtx");
+
+    auto loc_cls = py::class_<Loc>(m, "Loc")
+                           .def(py::init<int, int, int>())
+                           .def_readwrite("x", &Loc::x)
+                           .def_readwrite("y", &Loc::y)
+                           .def_readwrite("z", &Loc::z)
+                           .def("__repr__", loc_repr_py);
+
+    auto ci_cls = py::class_<ContextualWrapper<CellInfo &>>(m, "CellInfo");
+    readwrite_wrapper<CellInfo &, decltype(&CellInfo::name), &CellInfo::name, conv_to_str<IdString>,
+                      conv_from_str<IdString>>::def_wrap(ci_cls, "name");
+    readwrite_wrapper<CellInfo &, decltype(&CellInfo::type), &CellInfo::type, conv_to_str<IdString>,
+                      conv_from_str<IdString>>::def_wrap(ci_cls, "type");
+    readonly_wrapper<CellInfo &, decltype(&CellInfo::attrs), &CellInfo::attrs, wrap_context<AttrMap &>>::def_wrap(
+            ci_cls, "attrs");
+    readonly_wrapper<CellInfo &, decltype(&CellInfo::params), &CellInfo::params, wrap_context<AttrMap &>>::def_wrap(
+            ci_cls, "params");
+    readonly_wrapper<CellInfo &, decltype(&CellInfo::ports), &CellInfo::ports, wrap_context<PortMap &>>::def_wrap(
+            ci_cls, "ports");
+    readwrite_wrapper<CellInfo &, decltype(&CellInfo::bel), &CellInfo::bel, conv_to_str<BelId>,
+                      conv_from_str<BelId>>::def_wrap(ci_cls, "bel");
+    readwrite_wrapper<CellInfo &, decltype(&CellInfo::belStrength), &CellInfo::belStrength, pass_through<PlaceStrength>,
+                      pass_through<PlaceStrength>>::def_wrap(ci_cls, "belStrength");
+
+    fn_wrapper_1a_v<CellInfo &, decltype(&CellInfo::addInput), &CellInfo::addInput, conv_from_str<IdString>>::def_wrap(
+            ci_cls, "addInput");
+    fn_wrapper_1a_v<CellInfo &, decltype(&CellInfo::addOutput), &CellInfo::addOutput,
+                    conv_from_str<IdString>>::def_wrap(ci_cls, "addOutput");
+    fn_wrapper_1a_v<CellInfo &, decltype(&CellInfo::addInout), &CellInfo::addInout, conv_from_str<IdString>>::def_wrap(
+            ci_cls, "addInout");
+
+    fn_wrapper_2a_v<CellInfo &, decltype(&CellInfo::setParam), &CellInfo::setParam, conv_from_str<IdString>,
+                    conv_from_str<Property>>::def_wrap(ci_cls, "setParam");
+    fn_wrapper_1a_v<CellInfo &, decltype(&CellInfo::unsetParam), &CellInfo::unsetParam,
+                    conv_from_str<IdString>>::def_wrap(ci_cls, "unsetParam");
+    fn_wrapper_2a_v<CellInfo &, decltype(&CellInfo::setAttr), &CellInfo::setAttr, conv_from_str<IdString>,
+                    conv_from_str<Property>>::def_wrap(ci_cls, "setAttr");
+    fn_wrapper_1a_v<CellInfo &, decltype(&CellInfo::unsetAttr), &CellInfo::unsetAttr,
+                    conv_from_str<IdString>>::def_wrap(ci_cls, "unsetAttr");
+
+    auto pi_cls = py::class_<ContextualWrapper<PortInfo &>>(m, "PortInfo");
+    readwrite_wrapper<PortInfo &, decltype(&PortInfo::name), &PortInfo::name, conv_to_str<IdString>,
+                      conv_from_str<IdString>>::def_wrap(pi_cls, "name");
+    readonly_wrapper<PortInfo &, decltype(&PortInfo::net), &PortInfo::net, deref_and_wrap<NetInfo>>::def_wrap(pi_cls,
+                                                                                                              "net");
+    readwrite_wrapper<PortInfo &, decltype(&PortInfo::type), &PortInfo::type, pass_through<PortType>,
+                      pass_through<PortType>>::def_wrap(pi_cls, "type");
+
+    typedef indexed_store<PortRef> PortRefVector;
+    typedef dict<WireId, PipMap> WireMap;
+    typedef pool<BelId> BelSet;
+    typedef pool<WireId> WireSet;
+
+    auto ni_cls = py::class_<ContextualWrapper<NetInfo &>>(m, "NetInfo");
+    readwrite_wrapper<NetInfo &, decltype(&NetInfo::name), &NetInfo::name, conv_to_str<IdString>,
+                      conv_from_str<IdString>>::def_wrap(ni_cls, "name");
+    readonly_wrapper<NetInfo &, decltype(&NetInfo::driver), &NetInfo::driver, wrap_context<PortRef>>::def_wrap(
+            ni_cls, "driver");
+    readonly_wrapper<NetInfo &, decltype(&NetInfo::users), &NetInfo::users, wrap_context<PortRefVector &>>::def_wrap(
+            ni_cls, "users");
+    readonly_wrapper<NetInfo &, decltype(&NetInfo::wires), &NetInfo::wires, wrap_context<WireMap &>>::def_wrap(ni_cls,
+                                                                                                               "wires");
+
+    auto pr_cls = py::class_<ContextualWrapper<PortRef>>(m, "PortRef");
+    readonly_wrapper<PortRef, decltype(&PortRef::cell), &PortRef::cell, deref_and_wrap<CellInfo>>::def_wrap(pr_cls,
+                                                                                                            "cell");
+    readonly_wrapper<PortRef, decltype(&PortRef::port), &PortRef::port, conv_to_str<IdString>>::def_wrap(pr_cls,
+                                                                                                         "port");
+    readonly_wrapper<PortRef, decltype(&PortRef::budget), &PortRef::budget, pass_through<delay_t>>::def_wrap(pr_cls,
+                                                                                                             "budget");
+
+    auto pm_cls = py::class_<ContextualWrapper<PipMap &>>(m, "PipMap");
+    readwrite_wrapper<PipMap &, decltype(&PipMap::pip), &PipMap::pip, conv_to_str<PipId>,
+                      conv_from_str<PipId>>::def_wrap(pm_cls, "pip");
+    readwrite_wrapper<PipMap &, decltype(&PipMap::strength), &PipMap::strength, pass_through<PlaceStrength>,
+                      pass_through<PlaceStrength>>::def_wrap(pm_cls, "strength");
+
+    m.def("parse_json", parse_json_shim);
+    m.def("load_design", load_design_shim, py::return_value_policy::take_ownership);
+
+    auto region_cls = py::class_<ContextualWrapper<Region &>>(m, "Region");
+    readwrite_wrapper<Region &, decltype(&Region::name), &Region::name, conv_to_str<IdString>,
+                      conv_from_str<IdString>>::def_wrap(region_cls, "name");
+    readwrite_wrapper<Region &, decltype(&Region::constr_bels), &Region::constr_bels, pass_through<bool>,
+                      pass_through<bool>>::def_wrap(region_cls, "constr_bels");
+    readwrite_wrapper<Region &, decltype(&Region::constr_wires), &Region::constr_wires, pass_through<bool>,
+                      pass_through<bool>>::def_wrap(region_cls, "constr_bels");
+    readwrite_wrapper<Region &, decltype(&Region::constr_pips), &Region::constr_pips, pass_through<bool>,
+                      pass_through<bool>>::def_wrap(region_cls, "constr_pips");
+    readonly_wrapper<Region &, decltype(&Region::bels), &Region::bels, wrap_context<BelSet &>>::def_wrap(region_cls,
+                                                                                                         "bels");
+    readonly_wrapper<Region &, decltype(&Region::wires), &Region::wires, wrap_context<WireSet &>>::def_wrap(region_cls,
+                                                                                                            "wires");
+
+    auto hierarchy_cls = py::class_<ContextualWrapper<HierarchicalCell &>>(m, "HierarchicalCell");
+    readwrite_wrapper<HierarchicalCell &, decltype(&HierarchicalCell::name), &HierarchicalCell::name,
+                      conv_to_str<IdString>, conv_from_str<IdString>>::def_wrap(hierarchy_cls, "name");
+    readwrite_wrapper<HierarchicalCell &, decltype(&HierarchicalCell::type), &HierarchicalCell::type,
+                      conv_to_str<IdString>, conv_from_str<IdString>>::def_wrap(hierarchy_cls, "type");
+    readwrite_wrapper<HierarchicalCell &, decltype(&HierarchicalCell::parent), &HierarchicalCell::parent,
+                      conv_to_str<IdString>, conv_from_str<IdString>>::def_wrap(hierarchy_cls, "parent");
+    readwrite_wrapper<HierarchicalCell &, decltype(&HierarchicalCell::fullpath), &HierarchicalCell::fullpath,
+                      conv_to_str<IdString>, conv_from_str<IdString>>::def_wrap(hierarchy_cls, "fullpath");
+
+    readonly_wrapper<HierarchicalCell &, decltype(&HierarchicalCell::leaf_cells), &HierarchicalCell::leaf_cells,
+                     wrap_context<IdIdMap &>>::def_wrap(hierarchy_cls, "leaf_cells");
+    readonly_wrapper<HierarchicalCell &, decltype(&HierarchicalCell::nets), &HierarchicalCell::nets,
+                     wrap_context<IdIdMap &>>::def_wrap(hierarchy_cls, "nets");
+    readonly_wrapper<HierarchicalCell &, decltype(&HierarchicalCell::hier_cells), &HierarchicalCell::hier_cells,
+                     wrap_context<IdIdMap &>>::def_wrap(hierarchy_cls, "hier_cells");
+    WRAP_MAP(m, AttrMap, conv_to_str<Property>, "AttrMap");
+    WRAP_MAP(m, PortMap, wrap_context<PortInfo &>, "PortMap");
+    WRAP_MAP(m, IdIdMap, conv_to_str<IdString>, "IdIdMap");
+    WRAP_MAP(m, WireMap, wrap_context<PipMap &>, "WireMap");
+    WRAP_MAP_UPTR(m, RegionMap, "RegionMap");
+
+    WRAP_INDEXSTORE(m, PortRefVector, wrap_context<PortRef>);
+
+    typedef dict<IdString, ClockFmax> ClockFmaxMap;
+    WRAP_MAP(m, ClockFmaxMap, pass_through<ClockFmax>, "ClockFmaxMap");
+
+    auto clk_fmax_cls = py::class_<ClockFmax>(m, "ClockFmax")
+                                .def_readonly("achieved", &ClockFmax::achieved)
+                                .def_readonly("constraint", &ClockFmax::constraint);
+
+    auto tmg_result_cls = py::class_<ContextualWrapper<TimingResult &>>(m, "TimingResult");
+    readonly_wrapper<TimingResult &, decltype(&TimingResult::clock_fmax), &TimingResult::clock_fmax,
+                     wrap_context<ClockFmaxMap &>>::def_wrap(tmg_result_cls, "clock_fmax");
+    arch_wrap_python(m);
+}
+
+#ifdef MAIN_EXECUTABLE
+static wchar_t *program;
+#endif
+
+void (*python_sighandler)(int) = nullptr;
+
+void init_python(const char *executable)
+{
+#ifdef MAIN_EXECUTABLE
+    program = Py_DecodeLocale(executable, NULL);
+    if (program == NULL) {
+        fprintf(stderr, "Fatal error: cannot decode executable filename\n");
+        exit(1);
+    }
+    Py_SetProgramName(program);
+    py::initialize_interpreter();
+    py::module::import(TOSTRING(MODULE_NAME));
+    PyRun_SimpleString("from " TOSTRING(MODULE_NAME) " import *");
+    python_sighandler = signal(SIGINT, SIG_DFL);
+#endif
+}
+
+void deinit_python()
+{
+#ifdef MAIN_EXECUTABLE
+    py::finalize_interpreter();
+    PyMem_RawFree(program);
+#endif
+}
+
+void execute_python_file(const char *python_file)
+{
+    try {
+        FILE *fp = fopen(python_file, "r");
+        if (fp == NULL) {
+            fprintf(stderr, "Fatal error: file not found %s\n", python_file);
+            exit(1);
+        }
+        if (python_sighandler)
+            signal(SIGINT, python_sighandler);
+        int result = PyRun_SimpleFile(fp, python_file);
+        signal(SIGINT, SIG_DFL);
+        fclose(fp);
+        if (result == -1) {
+            log_error("Error occurred while executing Python script %s\n", python_file);
+        }
+    } catch (py::error_already_set const &) {
+        // Parse and output the exception
+        std::string perror_str = parse_python_exception();
+        signal(SIGINT, SIG_DFL);
+        log_error("Error in Python: %s\n", perror_str.c_str());
+    }
+}
+
+NEXTPNR_NAMESPACE_END
+
+#endif // NO_PYTHON
diff --git a/common/kernel/pybindings.h b/common/kernel/pybindings.h
new file mode 100644
index 00000000..695441f3
--- /dev/null
+++ b/common/kernel/pybindings.h
@@ -0,0 +1,93 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef COMMON_PYBINDINGS_H
+#define COMMON_PYBINDINGS_H
+
+#include <Python.h>
+#include <iostream>
+#include <pybind11/embed.h>
+#include <pybind11/pybind11.h>
+#include <stdexcept>
+#include <utility>
+#include "pycontainers.h"
+#include "pywrappers.h"
+
+#include "nextpnr.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+namespace py = pybind11;
+
+std::string parse_python_exception();
+
+template <typename Tn> void python_export_global(const char *name, Tn &x)
+{
+    try {
+        py::object obj = py::cast(x, py::return_value_policy::reference);
+        py::module::import("__main__").attr(name) = obj.ptr();
+    } catch (pybind11::error_already_set &) {
+        // Parse and output the exception
+        std::string perror_str = parse_python_exception();
+        std::cout << "Error in Python: " << perror_str << std::endl;
+        std::terminate();
+    }
+};
+
+void init_python(const char *executable);
+
+void deinit_python();
+
+void execute_python_file(const char *python_file);
+
+// Defauld IdString conversions
+namespace PythonConversion {
+
+template <> struct string_converter<IdString>
+{
+    inline IdString from_str(Context *ctx, std::string name) { return ctx->id(name); }
+
+    inline std::string to_str(Context *ctx, IdString id) { return id.str(ctx); }
+};
+
+template <> struct string_converter<const IdString>
+{
+    inline IdString from_str(Context *ctx, std::string name) { return ctx->id(name); }
+
+    inline std::string to_str(Context *ctx, IdString id) { return id.str(ctx); }
+};
+
+template <> struct string_converter<IdStringList>
+{
+    IdStringList from_str(Context *ctx, std::string name) { return IdStringList::parse(ctx, name); }
+    std::string to_str(Context *ctx, const IdStringList &id) { return id.str(ctx); }
+};
+
+template <> struct string_converter<const IdStringList>
+{
+    IdStringList from_str(Context *ctx, std::string name) { return IdStringList::parse(ctx, name); }
+    std::string to_str(Context *ctx, const IdStringList &id) { return id.str(ctx); }
+};
+
+} // namespace PythonConversion
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* end of include guard: COMMON_PYBINDINGS_HH */
diff --git a/common/kernel/pycontainers.h b/common/kernel/pycontainers.h
new file mode 100644
index 00000000..ff49c34c
--- /dev/null
+++ b/common/kernel/pycontainers.h
@@ -0,0 +1,575 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef COMMON_PYCONTAINERS_H
+#define COMMON_PYCONTAINERS_H
+
+#include <pybind11/pybind11.h>
+#include <sstream>
+#include <stdexcept>
+#include <type_traits>
+#include <utility>
+#include "nextpnr.h"
+#include "pywrappers.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+namespace py = pybind11;
+
+inline void KeyError()
+{
+    PyErr_SetString(PyExc_KeyError, "Key not found");
+    throw py::error_already_set();
+}
+
+/*
+A wrapper for a Pythonised nextpnr Iterator. The actual class wrapped is a
+pair<Iterator, Iterator> containing (current, end), wrapped in a ContextualWrapper
+
+*/
+
+template <typename T, py::return_value_policy P, typename value_conv = PythonConversion::pass_through<T>>
+struct iterator_wrapper
+{
+    typedef decltype(*(std::declval<T>())) value_t;
+
+    typedef PythonConversion::ContextualWrapper<std::pair<T, T>> wrapped_iter_t;
+    using return_t = typename value_conv::ret_type;
+
+    static return_t next(wrapped_iter_t &iter)
+    {
+        if (iter.base.first != iter.base.second) {
+            return_t val = value_conv()(iter.ctx, *iter.base.first);
+            ++iter.base.first;
+            return val;
+        } else {
+            PyErr_SetString(PyExc_StopIteration, "End of range reached");
+            throw py::error_already_set();
+        }
+    }
+
+    static void wrap(py::module &m, const char *python_name)
+    {
+        py::class_<wrapped_iter_t>(m, python_name).def("__next__", next, P);
+    }
+};
+
+/*
+A pair that doesn't automatically become a tuple
+*/
+template <typename Ta, typename Tb> struct iter_pair
+{
+    iter_pair(){};
+    iter_pair(const Ta &first, const Tb &second) : first(first), second(second){};
+    Ta first;
+    Tb second;
+};
+
+/*
+A wrapper for a nextpnr Range. Ranges should have two functions, begin()
+and end() which return iterator-like objects supporting ++, * and !=
+Full STL iterator semantics are not required, unlike the standard Boost wrappers
+*/
+
+template <typename T, py::return_value_policy P = py::return_value_policy::copy,
+          typename value_conv = PythonConversion::pass_through<T>>
+struct range_wrapper
+{
+    typedef decltype(std::declval<T>().begin()) iterator_t;
+    typedef decltype(*(std::declval<iterator_t>())) value_t;
+    typedef typename PythonConversion::ContextualWrapper<T> wrapped_range;
+    typedef typename PythonConversion::ContextualWrapper<std::pair<iterator_t, iterator_t>> wrapped_pair;
+    static wrapped_pair iter(wrapped_range &range)
+    {
+        return wrapped_pair(range.ctx, std::make_pair(range.base.begin(), range.base.end()));
+    }
+
+    static std::string repr(wrapped_range &range)
+    {
+        PythonConversion::string_converter<value_t> conv;
+        bool first = true;
+        std::stringstream ss;
+        ss << "[";
+        for (const auto &item : range.base) {
+            if (!first)
+                ss << ", ";
+            ss << "'" << conv.to_str(range.ctx, item) << "'";
+            first = false;
+        }
+        ss << "]";
+        return ss.str();
+    }
+
+    static void wrap(py::module &m, const char *range_name, const char *iter_name)
+    {
+        py::class_<wrapped_range>(m, range_name).def("__iter__", iter).def("__repr__", repr);
+        iterator_wrapper<iterator_t, P, value_conv>().wrap(m, iter_name);
+    }
+
+    typedef iterator_wrapper<iterator_t, P, value_conv> iter_wrap;
+};
+
+#define WRAP_RANGE(m, t, conv)                                                                                         \
+    range_wrapper<t##Range, py::return_value_policy::copy, conv>().wrap(m, #t "Range", #t "Iterator")
+
+/*
+A wrapper for a vector or similar structure. With support for conversion
+*/
+
+template <typename T, py::return_value_policy P = py::return_value_policy::copy,
+          typename value_conv = PythonConversion::pass_through<T>>
+struct vector_wrapper
+{
+    typedef decltype(std::declval<T>().begin()) iterator_t;
+    typedef decltype(*(std::declval<iterator_t>())) value_t;
+    typedef typename PythonConversion::ContextualWrapper<T &> wrapped_vector;
+    typedef typename PythonConversion::ContextualWrapper<std::pair<iterator_t, iterator_t>> wrapped_pair;
+    using return_t = typename value_conv::ret_type;
+    static wrapped_pair iter(wrapped_vector &range)
+    {
+        return wrapped_pair(range.ctx, std::make_pair(range.base.begin(), range.base.end()));
+    }
+
+    static std::string repr(wrapped_vector &range)
+    {
+        PythonConversion::string_converter<value_t> conv;
+        bool first = true;
+        std::stringstream ss;
+        ss << "[";
+        for (const auto &item : range.base) {
+            if (!first)
+                ss << ", ";
+            ss << "'" << conv.to_str(range.ctx, item) << "'";
+            first = false;
+        }
+        ss << "]";
+        return ss.str();
+    }
+
+    static int len(wrapped_vector &range) { return range.base.size(); }
+
+    static return_t getitem(wrapped_vector &range, int i)
+    {
+        return value_conv()(range.ctx, boost::ref(range.base.at(i)));
+    }
+
+    static void wrap(py::module &m, const char *range_name, const char *iter_name)
+    {
+        py::class_<wrapped_vector>(m, range_name)
+                .def("__iter__", iter)
+                .def("__repr__", repr)
+                .def("__len__", len)
+                .def("__getitem__", getitem);
+
+        iterator_wrapper<iterator_t, P, value_conv>().wrap(m, iter_name);
+    }
+
+    typedef iterator_wrapper<iterator_t, P, value_conv> iter_wrap;
+};
+
+#define WRAP_VECTOR(m, t, conv) vector_wrapper<t, py::return_value_policy::copy, conv>().wrap(m, #t, #t "Iterator")
+
+template <typename T, py::return_value_policy P = py::return_value_policy::copy,
+          typename value_conv = PythonConversion::pass_through<T>>
+struct indexed_store_wrapper
+{
+    typedef decltype(std::declval<T>().begin()) iterator_t;
+    typedef decltype(*(std::declval<iterator_t>())) value_t;
+    typedef typename PythonConversion::ContextualWrapper<T &> wrapped_vector;
+    typedef typename PythonConversion::ContextualWrapper<std::pair<iterator_t, iterator_t>> wrapped_pair;
+    using return_t = typename value_conv::ret_type;
+    static wrapped_pair iter(wrapped_vector &range)
+    {
+        return wrapped_pair(range.ctx, std::make_pair(range.base.begin(), range.base.end()));
+    }
+
+    static std::string repr(wrapped_vector &range)
+    {
+        PythonConversion::string_converter<value_t> conv;
+        bool first = true;
+        std::stringstream ss;
+        ss << "[";
+        for (const auto &item : range.base) {
+            if (!first)
+                ss << ", ";
+            ss << "'" << conv.to_str(range.ctx, item) << "'";
+            first = false;
+        }
+        ss << "]";
+        return ss.str();
+    }
+
+    static int len(wrapped_vector &range) { return range.base.capacity(); }
+
+    static py::object getitem(wrapped_vector &range, int i)
+    {
+        store_index<std::remove_reference_t<value_t>> idx(i);
+        if (!range.base.count(idx))
+            throw py::none();
+        return py::cast(value_conv()(range.ctx, boost::ref(range.base.at(idx))));
+    }
+
+    static void wrap(py::module &m, const char *range_name, const char *iter_name)
+    {
+        py::class_<wrapped_vector>(m, range_name)
+                .def("__iter__", iter)
+                .def("__repr__", repr)
+                .def("__len__", len)
+                .def("__getitem__", getitem);
+
+        iterator_wrapper<iterator_t, P, value_conv>().wrap(m, iter_name);
+    }
+
+    typedef iterator_wrapper<iterator_t, P, value_conv> iter_wrap;
+};
+
+#define WRAP_INDEXSTORE(m, t, conv)                                                                                    \
+    indexed_store_wrapper<t, py::return_value_policy::copy, conv>().wrap(m, #t, #t "Iterator")
+
+/*
+Wrapper for a pair, allows accessing either using C++-style members (.first and
+.second) or as a Python iterable and indexable object
+*/
+template <typename T1, typename T2> struct pair_wrapper
+{
+    typedef std::pair<T1, T2> T;
+
+    struct pair_iterator_wrapper
+    {
+        static py::object next(iter_pair<T &, int> &iter)
+        {
+            if (iter.second == 0) {
+                iter.second++;
+                return py::cast(iter.first.first);
+            } else if (iter.second == 1) {
+                iter.second++;
+                return py::cast(iter.first.second);
+            } else {
+                PyErr_SetString(PyExc_StopIteration, "End of range reached");
+                throw py::error_already_set();
+            }
+        }
+
+        static void wrap(py::module &m, const char *python_name)
+        {
+            py::class_<iter_pair<T &, int>>(m, python_name).def("__next__", next);
+        }
+    };
+
+    static py::object get(T &x, int i)
+    {
+        if ((i >= 2) || (i < 0))
+            KeyError();
+        return (i == 1) ? py::object(x.second) : py::object(x.first);
+    }
+
+    static void set(T &x, int i, py::object val)
+    {
+        if ((i >= 2) || (i < 0))
+            KeyError();
+        if (i == 0)
+            x.first = val.cast<T1>();
+        if (i == 1)
+            x.second = val.cast<T2>();
+    }
+
+    static int len(T &x) { return 2; }
+
+    static iter_pair<T &, int> iter(T &x) { return iter_pair<T &, int>(boost::ref(x), 0); };
+
+    static void wrap(py::module &m, const char *pair_name, const char *iter_name)
+    {
+        pair_iterator_wrapper::wrap(m, iter_name);
+        py::class_<T>(m, pair_name)
+                .def("__iter__", iter)
+                .def("__len__", len)
+                .def("__getitem__", get)
+                .def("__setitem__", set, py::keep_alive<1, 2>())
+                .def_readwrite("first", &T::first)
+                .def_readwrite("second", &T::second);
+    }
+};
+
+/*
+Special case of above for map key/values
+ */
+template <typename T1, typename T2, typename value_conv> struct map_pair_wrapper
+{
+    typedef std::pair<T1, T2> T;
+    typedef PythonConversion::ContextualWrapper<T &> wrapped_pair;
+    typedef typename T::second_type V;
+
+    struct pair_iterator_wrapper
+    {
+        static py::object next(iter_pair<wrapped_pair &, int> &iter)
+        {
+            if (iter.second == 0) {
+                iter.second++;
+                return py::cast(PythonConversion::string_converter<decltype(iter.first.base.first)>().to_str(
+                        iter.first.ctx, iter.first.base.first));
+            } else if (iter.second == 1) {
+                iter.second++;
+                return py::cast(value_conv()(iter.first.ctx, iter.first.base.second));
+            } else {
+                PyErr_SetString(PyExc_StopIteration, "End of range reached");
+                throw py::error_already_set();
+            }
+        }
+
+        static void wrap(py::module &m, const char *python_name)
+        {
+            py::class_<iter_pair<wrapped_pair &, int>>(m, python_name).def("__next__", next);
+        }
+    };
+
+    static py::object get(wrapped_pair &x, int i)
+    {
+        if ((i >= 2) || (i < 0))
+            KeyError();
+        return (i == 1) ? py::cast(value_conv()(x.ctx, x.base.second))
+                        : py::cast(PythonConversion::string_converter<decltype(x.base.first)>().to_str(x.ctx,
+                                                                                                       x.base.first));
+    }
+
+    static int len(wrapped_pair &x) { return 2; }
+
+    static iter_pair<wrapped_pair &, int> iter(wrapped_pair &x)
+    {
+        return iter_pair<wrapped_pair &, int>(boost::ref(x), 0);
+    };
+
+    static std::string first_getter(wrapped_pair &t)
+    {
+        return PythonConversion::string_converter<decltype(t.base.first)>().to_str(t.ctx, t.base.first);
+    }
+
+    static typename value_conv::ret_type second_getter(wrapped_pair &t) { return value_conv()(t.ctx, t.base.second); }
+
+    static void wrap(py::module &m, const char *pair_name, const char *iter_name)
+    {
+        pair_iterator_wrapper::wrap(m, iter_name);
+        py::class_<wrapped_pair>(m, pair_name)
+                .def("__iter__", iter)
+                .def("__len__", len)
+                .def("__getitem__", get)
+                .def_property_readonly("first", first_getter)
+                .def_property_readonly("second", second_getter);
+    }
+};
+
+/*
+Wrapper for a map, either an unordered_map, regular map or dict
+ */
+
+template <typename T, typename value_conv> struct map_wrapper
+{
+    typedef typename std::remove_cv<typename std::remove_reference<typename T::key_type>::type>::type K;
+    typedef typename T::mapped_type V;
+    typedef typename value_conv::ret_type wrapped_V;
+    typedef typename T::value_type KV;
+    typedef typename PythonConversion::ContextualWrapper<T &> wrapped_map;
+
+    static wrapped_V get(wrapped_map &x, std::string const &i)
+    {
+        K k = PythonConversion::string_converter<K>().from_str(x.ctx, i);
+        if (x.base.find(k) != x.base.end())
+            return value_conv()(x.ctx, x.base.at(k));
+        KeyError();
+
+        // Should be unreachable, but prevent control may reach end of non-void
+        throw std::runtime_error("unreachable");
+    }
+
+    static void set(wrapped_map &x, std::string const &i, V const &v)
+    {
+        x.base[PythonConversion::string_converter<K>().from_str(x.ctx, i)] = v;
+    }
+
+    static size_t len(wrapped_map &x) { return x.base.size(); }
+
+    static void del(T const &x, std::string const &i)
+    {
+        K k = PythonConversion::string_converter<K>().from_str(x.ctx, i);
+        if (x.base.find(k) != x.base.end())
+            x.base.erase(k);
+        else
+            KeyError();
+    }
+
+    static bool contains(wrapped_map &x, std::string const &i)
+    {
+        K k = PythonConversion::string_converter<K>().from_str(x.ctx, i);
+        return x.base.count(k);
+    }
+
+    static void wrap(py::module &m, const char *map_name, const char *kv_name, const char *kv_iter_name,
+                     const char *iter_name)
+    {
+        map_pair_wrapper<typename KV::first_type, typename KV::second_type, value_conv>::wrap(m, kv_name, kv_iter_name);
+        typedef range_wrapper<T &, py::return_value_policy::copy, PythonConversion::wrap_context<KV &>> rw;
+        typename rw::iter_wrap().wrap(m, iter_name);
+        py::class_<wrapped_map>(m, map_name)
+                .def("__iter__", rw::iter)
+                .def("__len__", len)
+                .def("__contains__", contains)
+                .def("__getitem__", get)
+                .def("__setitem__", set, py::keep_alive<1, 2>());
+    }
+};
+
+/*
+Special case of above for map key/values where value is a unique_ptr
+ */
+template <typename T1, typename T2> struct map_pair_wrapper_uptr
+{
+    typedef std::pair<T1, T2> T;
+    typedef PythonConversion::ContextualWrapper<T &> wrapped_pair;
+    typedef typename T::second_type::element_type V;
+
+    struct pair_iterator_wrapper
+    {
+        static py::object next(iter_pair<wrapped_pair &, int> &iter)
+        {
+            if (iter.second == 0) {
+                iter.second++;
+                return py::cast(PythonConversion::string_converter<decltype(iter.first.base.first)>().to_str(
+                        iter.first.ctx, iter.first.base.first));
+            } else if (iter.second == 1) {
+                iter.second++;
+                return py::cast(
+                        PythonConversion::ContextualWrapper<V &>(iter.first.ctx, *iter.first.base.second.get()));
+            } else {
+                PyErr_SetString(PyExc_StopIteration, "End of range reached");
+                throw py::error_already_set();
+            }
+        }
+
+        static void wrap(py::module &m, const char *python_name)
+        {
+            py::class_<iter_pair<wrapped_pair &, int>>(m, python_name).def("__next__", next);
+        }
+    };
+
+    static py::object get(wrapped_pair &x, int i)
+    {
+        if ((i >= 2) || (i < 0))
+            KeyError();
+        return (i == 1) ? py::cast(PythonConversion::ContextualWrapper<V &>(x.ctx, *x.base.second.get()))
+                        : py::cast(PythonConversion::string_converter<decltype(x.base.first)>().to_str(x.ctx,
+                                                                                                       x.base.first));
+    }
+
+    static int len(wrapped_pair &x) { return 2; }
+
+    static iter_pair<wrapped_pair &, int> iter(wrapped_pair &x)
+    {
+        return iter_pair<wrapped_pair &, int>(boost::ref(x), 0);
+    };
+
+    static std::string first_getter(wrapped_pair &t)
+    {
+        return PythonConversion::string_converter<decltype(t.base.first)>().to_str(t.ctx, t.base.first);
+    }
+
+    static PythonConversion::ContextualWrapper<V &> second_getter(wrapped_pair &t)
+    {
+        return PythonConversion::ContextualWrapper<V &>(t.ctx, *t.base.second.get());
+    }
+
+    static void wrap(py::module &m, const char *pair_name, const char *iter_name)
+    {
+        pair_iterator_wrapper::wrap(m, iter_name);
+        py::class_<wrapped_pair>(m, pair_name)
+                .def("__iter__", iter)
+                .def("__len__", len)
+                .def("__getitem__", get)
+                .def_property_readonly("first", first_getter)
+                .def_property_readonly("second", second_getter);
+    }
+};
+
+/*
+Wrapper for a map, either an unordered_map, regular map or dict
+ */
+
+template <typename T> struct map_wrapper_uptr
+{
+    typedef typename std::remove_cv<typename std::remove_reference<typename T::key_type>::type>::type K;
+    typedef typename T::mapped_type::pointer V;
+    typedef typename T::mapped_type::element_type &Vr;
+    typedef typename T::value_type KV;
+    typedef typename PythonConversion::ContextualWrapper<T &> wrapped_map;
+
+    static PythonConversion::ContextualWrapper<Vr> get(wrapped_map &x, std::string const &i)
+    {
+        K k = PythonConversion::string_converter<K>().from_str(x.ctx, i);
+        if (x.base.find(k) != x.base.end())
+            return PythonConversion::ContextualWrapper<Vr>(x.ctx, *x.base.at(k).get());
+        KeyError();
+
+        // Should be unreachable, but prevent control may reach end of non-void
+        throw std::runtime_error("unreachable");
+    }
+
+    static void set(wrapped_map &x, std::string const &i, V const &v)
+    {
+        x.base[PythonConversion::string_converter<K>().from_str(x.ctx, i)] = typename T::mapped_type(v);
+    }
+
+    static size_t len(wrapped_map &x) { return x.base.size(); }
+
+    static void del(T const &x, std::string const &i)
+    {
+        K k = PythonConversion::string_converter<K>().from_str(x.ctx, i);
+        if (x.base.find(k) != x.base.end())
+            x.base.erase(k);
+        else
+            KeyError();
+    }
+
+    static bool contains(wrapped_map &x, std::string const &i)
+    {
+        K k = PythonConversion::string_converter<K>().from_str(x.ctx, i);
+        return x.base.count(k);
+    }
+
+    static void wrap(py::module &m, const char *map_name, const char *kv_name, const char *kv_iter_name,
+                     const char *iter_name)
+    {
+        map_pair_wrapper_uptr<typename KV::first_type, typename KV::second_type>::wrap(m, kv_name, kv_iter_name);
+        typedef range_wrapper<T &, py::return_value_policy::copy, PythonConversion::wrap_context<KV &>> rw;
+        typename rw::iter_wrap().wrap(m, iter_name);
+        py::class_<wrapped_map>(m, map_name)
+                .def("__iter__", rw::iter)
+                .def("__len__", len)
+                .def("__contains__", contains)
+                .def("__getitem__", get)
+                .def("__setitem__", set, py::keep_alive<1, 2>());
+    }
+};
+
+#define WRAP_MAP(m, t, conv, name)                                                                                     \
+    map_wrapper<t, conv>().wrap(m, #name, #name "KeyValue", #name "KeyValueIter", #name "Iterator")
+#define WRAP_MAP_UPTR(m, t, name)                                                                                      \
+    map_wrapper_uptr<t>().wrap(m, #name, #name "KeyValue", #name "KeyValueIter", #name "Iterator")
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/pywrappers.h b/common/kernel/pywrappers.h
new file mode 100644
index 00000000..60ef65be
--- /dev/null
+++ b/common/kernel/pywrappers.h
@@ -0,0 +1,463 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef PYWRAPPERS_H
+#define PYWRAPPERS_H
+
+#include <pybind11/pybind11.h>
+#include <utility>
+#include "nextpnr.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+namespace py = pybind11;
+
+namespace PythonConversion {
+template <typename T> struct ContextualWrapper
+{
+    Context *ctx;
+    T base;
+
+    inline ContextualWrapper(Context *c, T x) : ctx(c), base(x){};
+
+    inline operator T() { return base; };
+    typedef T base_type;
+};
+
+template <typename T> struct WrapIfNotContext
+{
+    typedef ContextualWrapper<T> maybe_wrapped_t;
+};
+
+template <> struct WrapIfNotContext<Context>
+{
+    typedef Context maybe_wrapped_t;
+};
+
+template <typename T> inline Context *get_ctx(typename WrapIfNotContext<T>::maybe_wrapped_t &wrp_ctx)
+{
+    return wrp_ctx.ctx;
+}
+
+template <> inline Context *get_ctx<Context>(WrapIfNotContext<Context>::maybe_wrapped_t &unwrp_ctx)
+{
+    return &unwrp_ctx;
+}
+
+template <typename T> inline T &get_base(typename WrapIfNotContext<T>::maybe_wrapped_t &wrp_ctx)
+{
+    return wrp_ctx.base;
+}
+
+template <> inline Context &get_base<Context>(WrapIfNotContext<Context>::maybe_wrapped_t &unwrp_ctx)
+{
+    return unwrp_ctx;
+}
+
+template <typename T> ContextualWrapper<T> wrap_ctx(Context *ctx, T x) { return ContextualWrapper<T>(ctx, x); }
+
+// Dummy class, to be implemented by users
+template <typename T> struct string_converter;
+
+class bad_wrap
+{
+};
+
+// Action options
+template <typename T> struct pass_through
+{
+    inline T operator()(Context *ctx, T x) { return x; }
+
+    using ret_type = T;
+    using arg_type = T;
+};
+
+template <typename T> struct wrap_context
+{
+    inline ContextualWrapper<T> operator()(Context *ctx, T x) { return ContextualWrapper<T>(ctx, x); }
+
+    using arg_type = T;
+    using ret_type = ContextualWrapper<T>;
+};
+
+template <typename T> struct unwrap_context
+{
+    inline T operator()(Context *ctx, ContextualWrapper<T> x) { return x.base; }
+
+    using ret_type = T;
+    using arg_type = ContextualWrapper<T>;
+};
+
+template <typename T> struct conv_from_str
+{
+    inline T operator()(Context *ctx, std::string x) { return string_converter<T>().from_str(ctx, x); }
+
+    using ret_type = T;
+    using arg_type = std::string;
+};
+
+template <typename T> struct conv_to_str
+{
+    inline std::string operator()(Context *ctx, T x) { return string_converter<T>().to_str(ctx, x); }
+
+    using ret_type = std::string;
+    using arg_type = T;
+};
+
+template <typename T> struct deref_and_wrap
+{
+    inline ContextualWrapper<T &> operator()(Context *ctx, T *x)
+    {
+        if (x == nullptr)
+            throw bad_wrap();
+        return ContextualWrapper<T &>(ctx, *x);
+    }
+
+    using arg_type = T *;
+    using ret_type = ContextualWrapper<T &>;
+};
+
+template <typename T> struct addr_and_unwrap
+{
+    inline T *operator()(Context *ctx, ContextualWrapper<T &> x) { return &(x.base); }
+
+    using arg_type = ContextualWrapper<T &>;
+    using ret_type = T *;
+};
+
+// Function wrapper
+// Zero parameters, one return
+template <typename Class, typename FuncT, FuncT fn, typename rv_conv> struct fn_wrapper_0a
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_result_type = typename rv_conv::ret_type;
+
+    static py::object wrapped_fn(class_type &cls)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        try {
+            return py::cast(rv_conv()(ctx, (base.*fn)()));
+        } catch (bad_wrap &) {
+            return py::none();
+        }
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// One parameter, one return
+template <typename Class, typename FuncT, FuncT fn, typename rv_conv, typename arg1_conv> struct fn_wrapper_1a
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_result_type = typename rv_conv::ret_type;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+
+    static py::object wrapped_fn(class_type &cls, conv_arg1_type arg1)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        try {
+            return py::cast(rv_conv()(ctx, (base.*fn)(arg1_conv()(ctx, arg1))));
+        } catch (bad_wrap &) {
+            return py::none();
+        }
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// Two parameters, one return
+template <typename Class, typename FuncT, FuncT fn, typename rv_conv, typename arg1_conv, typename arg2_conv>
+struct fn_wrapper_2a
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_result_type = typename rv_conv::ret_type;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+    using conv_arg2_type = typename arg2_conv::arg_type;
+
+    static py::object wrapped_fn(class_type &cls, conv_arg1_type arg1, conv_arg2_type arg2)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        try {
+            return py::cast(rv_conv()(ctx, (base.*fn)(arg1_conv()(ctx, arg1), arg2_conv()(ctx, arg2))));
+        } catch (bad_wrap &) {
+            return py::none();
+        }
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// Three parameters, one return
+template <typename Class, typename FuncT, FuncT fn, typename rv_conv, typename arg1_conv, typename arg2_conv,
+          typename arg3_conv>
+struct fn_wrapper_3a
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_result_type = typename rv_conv::ret_type;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+    using conv_arg2_type = typename arg2_conv::arg_type;
+    using conv_arg3_type = typename arg3_conv::arg_type;
+
+    static py::object wrapped_fn(class_type &cls, conv_arg1_type arg1, conv_arg2_type arg2, conv_arg3_type arg3)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        try {
+            return py::cast(
+                    rv_conv()(ctx, (base.*fn)(arg1_conv()(ctx, arg1), arg2_conv()(ctx, arg2), arg3_conv()(ctx, arg3))));
+        } catch (bad_wrap &) {
+            return py::none();
+        }
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// Zero parameters void
+template <typename Class, typename FuncT, FuncT fn> struct fn_wrapper_0a_v
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+
+    static void wrapped_fn(class_type &cls)
+    {
+        Class &base = get_base<Class>(cls);
+        return (base.*fn)();
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+};
+
+// One parameter, void
+template <typename Class, typename FuncT, FuncT fn, typename arg1_conv> struct fn_wrapper_1a_v
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+
+    static void wrapped_fn(class_type &cls, conv_arg1_type arg1)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        (base.*fn)(arg1_conv()(ctx, arg1));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+
+    template <typename WrapCls, typename Ta>
+    static void def_wrap(WrapCls cls_, const char *name, Ta a = py::arg("arg1"))
+    {
+        cls_.def(name, wrapped_fn, a);
+    }
+};
+
+// Two parameters, no return
+template <typename Class, typename FuncT, FuncT fn, typename arg1_conv, typename arg2_conv> struct fn_wrapper_2a_v
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+    using conv_arg2_type = typename arg2_conv::arg_type;
+
+    static void wrapped_fn(class_type &cls, conv_arg1_type arg1, conv_arg2_type arg2)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        (base.*fn)(arg1_conv()(ctx, arg1), arg2_conv()(ctx, arg2));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+
+    template <typename WrapCls, typename... Ta> static void def_wrap(WrapCls cls_, const char *name, Ta... a)
+    {
+        cls_.def(name, wrapped_fn, a...);
+    }
+};
+
+// Three parameters, no return
+template <typename Class, typename FuncT, FuncT fn, typename arg1_conv, typename arg2_conv, typename arg3_conv>
+struct fn_wrapper_3a_v
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+    using conv_arg2_type = typename arg2_conv::arg_type;
+    using conv_arg3_type = typename arg3_conv::arg_type;
+
+    static void wrapped_fn(class_type &cls, conv_arg1_type arg1, conv_arg2_type arg2, conv_arg3_type arg3)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        (base.*fn)(arg1_conv()(ctx, arg1), arg2_conv()(ctx, arg2), arg3_conv()(ctx, arg3));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+
+    template <typename WrapCls, typename... Ta> static void def_wrap(WrapCls cls_, const char *name, Ta... a)
+    {
+        cls_.def(name, wrapped_fn, a...);
+    }
+};
+
+// Four parameters, no return
+template <typename Class, typename FuncT, FuncT fn, typename arg1_conv, typename arg2_conv, typename arg3_conv,
+          typename arg4_conv>
+struct fn_wrapper_4a_v
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+    using conv_arg2_type = typename arg2_conv::arg_type;
+    using conv_arg3_type = typename arg3_conv::arg_type;
+    using conv_arg4_type = typename arg4_conv::arg_type;
+
+    static void wrapped_fn(class_type &cls, conv_arg1_type arg1, conv_arg2_type arg2, conv_arg3_type arg3,
+                           conv_arg4_type arg4)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        (base.*fn)(arg1_conv()(ctx, arg1), arg2_conv()(ctx, arg2), arg3_conv()(ctx, arg3), arg4_conv()(ctx, arg4));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+
+    template <typename WrapCls, typename... Ta> static void def_wrap(WrapCls cls_, const char *name, Ta... a)
+    {
+        cls_.def(name, wrapped_fn, a...);
+    }
+};
+
+// Five parameters, no return
+template <typename Class, typename FuncT, FuncT fn, typename arg1_conv, typename arg2_conv, typename arg3_conv,
+          typename arg4_conv, typename arg5_conv>
+struct fn_wrapper_5a_v
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+    using conv_arg2_type = typename arg2_conv::arg_type;
+    using conv_arg3_type = typename arg3_conv::arg_type;
+    using conv_arg4_type = typename arg4_conv::arg_type;
+    using conv_arg5_type = typename arg5_conv::arg_type;
+
+    static void wrapped_fn(class_type &cls, conv_arg1_type arg1, conv_arg2_type arg2, conv_arg3_type arg3,
+                           conv_arg4_type arg4, conv_arg5_type arg5)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        (base.*fn)(arg1_conv()(ctx, arg1), arg2_conv()(ctx, arg2), arg3_conv()(ctx, arg3), arg4_conv()(ctx, arg4),
+                   arg5_conv()(ctx, arg5));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+
+    template <typename WrapCls, typename... Ta> static void def_wrap(WrapCls cls_, const char *name, Ta... a)
+    {
+        cls_.def(name, wrapped_fn, a...);
+    }
+};
+
+// Six parameters, no return
+template <typename Class, typename FuncT, FuncT fn, typename arg1_conv, typename arg2_conv, typename arg3_conv,
+          typename arg4_conv, typename arg5_conv, typename arg6_conv>
+struct fn_wrapper_6a_v
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_arg1_type = typename arg1_conv::arg_type;
+    using conv_arg2_type = typename arg2_conv::arg_type;
+    using conv_arg3_type = typename arg3_conv::arg_type;
+    using conv_arg4_type = typename arg4_conv::arg_type;
+    using conv_arg5_type = typename arg5_conv::arg_type;
+    using conv_arg6_type = typename arg6_conv::arg_type;
+
+    static void wrapped_fn(class_type &cls, conv_arg1_type arg1, conv_arg2_type arg2, conv_arg3_type arg3,
+                           conv_arg4_type arg4, conv_arg5_type arg5, conv_arg6_type arg6)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        (base.*fn)(arg1_conv()(ctx, arg1), arg2_conv()(ctx, arg2), arg3_conv()(ctx, arg3), arg4_conv()(ctx, arg4),
+                   arg5_conv()(ctx, arg5), arg6_conv()(ctx, arg6));
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name) { cls_.def(name, wrapped_fn); }
+
+    template <typename WrapCls, typename... Ta> static void def_wrap(WrapCls cls_, const char *name, Ta... a)
+    {
+        cls_.def(name, wrapped_fn, a...);
+    }
+};
+
+// Wrapped getter
+template <typename Class, typename MemT, MemT mem, typename v_conv> struct readonly_wrapper
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_val_type = typename v_conv::ret_type;
+
+    static py::object wrapped_getter(class_type &cls)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        try {
+            return py::cast(v_conv()(ctx, (base.*mem)));
+        } catch (bad_wrap &) {
+            return py::none();
+        }
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name)
+    {
+        cls_.def_property_readonly(name, wrapped_getter);
+    }
+};
+
+// Wrapped getter/setter
+template <typename Class, typename MemT, MemT mem, typename get_conv, typename set_conv> struct readwrite_wrapper
+{
+    using class_type = typename WrapIfNotContext<Class>::maybe_wrapped_t;
+    using conv_val_type = typename get_conv::ret_type;
+
+    static py::object wrapped_getter(class_type &cls)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        try {
+            return py::cast(get_conv()(ctx, (base.*mem)));
+        } catch (bad_wrap &) {
+            return py::none();
+        }
+    }
+
+    using conv_arg_type = typename set_conv::arg_type;
+
+    static void wrapped_setter(class_type &cls, conv_arg_type val)
+    {
+        Context *ctx = get_ctx<Class>(cls);
+        Class &base = get_base<Class>(cls);
+        (base.*mem) = set_conv()(ctx, val);
+    }
+
+    template <typename WrapCls> static void def_wrap(WrapCls cls_, const char *name)
+    {
+        cls_.def_property(name, wrapped_getter, wrapped_setter);
+    }
+};
+
+} // namespace PythonConversion
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/relptr.h b/common/kernel/relptr.h
new file mode 100644
index 00000000..f0f45b7d
--- /dev/null
+++ b/common/kernel/relptr.h
@@ -0,0 +1,74 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef RELPTR_H
+#define RELPTR_H
+
+#include <cstdint>
+
+#include "nextpnr_assertions.h"
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+template <typename T> struct RelPtr
+{
+    int32_t offset;
+
+    const T *get() const { return reinterpret_cast<const T *>(reinterpret_cast<const char *>(this) + offset); }
+
+    const T &operator[](std::size_t index) const { return get()[index]; }
+
+    const T &operator*() const { return *(get()); }
+
+    const T *operator->() const { return get(); }
+
+    RelPtr(const RelPtr &) = delete;
+    RelPtr &operator=(const RelPtr &) = delete;
+};
+
+NPNR_PACKED_STRUCT(template <typename T> struct RelSlice {
+    int32_t offset;
+    uint32_t length;
+
+    const T *get() const { return reinterpret_cast<const T *>(reinterpret_cast<const char *>(this) + offset); }
+
+    const T &operator[](std::size_t index) const
+    {
+        NPNR_ASSERT(index < length);
+        return get()[index];
+    }
+
+    const T *begin() const { return get(); }
+    const T *end() const { return get() + length; }
+
+    size_t size() const { return length; }
+    ptrdiff_t ssize() const { return length; }
+
+    const T &operator*() const { return *(get()); }
+
+    const T *operator->() const { return get(); }
+
+    RelSlice(const RelSlice &) = delete;
+    RelSlice &operator=(const RelSlice &) = delete;
+});
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* RELPTR_H */
diff --git a/common/kernel/report.cc b/common/kernel/report.cc
new file mode 100644
index 00000000..98ff14fb
--- /dev/null
+++ b/common/kernel/report.cc
@@ -0,0 +1,259 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2021  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "json11.hpp"
+#include "nextpnr.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+using namespace json11;
+
+namespace {
+dict<IdString, std::pair<int, int>> get_utilization(const Context *ctx)
+{
+    // Sort by Bel type
+    dict<IdString, std::pair<int, int>> result;
+    for (auto &cell : ctx->cells) {
+        result[ctx->getBelBucketName(ctx->getBelBucketForCellType(cell.second.get()->type))].first++;
+    }
+    for (auto bel : ctx->getBels()) {
+        if (!ctx->getBelHidden(bel)) {
+            result[ctx->getBelBucketName(ctx->getBelBucketForBel(bel))].second++;
+        }
+    }
+    return result;
+}
+} // namespace
+
+static std::string clock_event_name(const Context *ctx, const ClockEvent &e)
+{
+    std::string value;
+    if (e.clock == ctx->id("$async$"))
+        value = std::string("<async>");
+    else
+        value = (e.edge == FALLING_EDGE ? std::string("negedge ") : std::string("posedge ")) + e.clock.str(ctx);
+    return value;
+};
+
+static Json::array report_critical_paths(const Context *ctx)
+{
+
+    auto report_critical_path = [ctx](const CriticalPath &report) {
+        Json::array pathJson;
+
+        for (const auto &segment : report.segments) {
+
+            const auto &driver = ctx->cells.at(segment.from.first);
+            const auto &sink = ctx->cells.at(segment.to.first);
+
+            auto fromLoc = ctx->getBelLocation(driver->bel);
+            auto toLoc = ctx->getBelLocation(sink->bel);
+
+            auto fromJson = Json::object({{"cell", segment.from.first.c_str(ctx)},
+                                          {"port", segment.from.second.c_str(ctx)},
+                                          {"loc", Json::array({fromLoc.x, fromLoc.y})}});
+
+            auto toJson = Json::object({{"cell", segment.to.first.c_str(ctx)},
+                                        {"port", segment.to.second.c_str(ctx)},
+                                        {"loc", Json::array({toLoc.x, toLoc.y})}});
+
+            auto segmentJson = Json::object({
+                    {"delay", ctx->getDelayNS(segment.delay)},
+                    {"from", fromJson},
+                    {"to", toJson},
+            });
+
+            if (segment.type == CriticalPath::Segment::Type::CLK_TO_Q) {
+                segmentJson["type"] = "clk-to-q";
+            } else if (segment.type == CriticalPath::Segment::Type::SOURCE) {
+                segmentJson["type"] = "source";
+            } else if (segment.type == CriticalPath::Segment::Type::LOGIC) {
+                segmentJson["type"] = "logic";
+            } else if (segment.type == CriticalPath::Segment::Type::SETUP) {
+                segmentJson["type"] = "setup";
+            } else if (segment.type == CriticalPath::Segment::Type::ROUTING) {
+                segmentJson["type"] = "routing";
+                segmentJson["net"] = segment.net.c_str(ctx);
+                segmentJson["budget"] = ctx->getDelayNS(segment.budget);
+            }
+
+            pathJson.push_back(segmentJson);
+        }
+
+        return pathJson;
+    };
+
+    auto critPathsJson = Json::array();
+
+    // Critical paths
+    for (auto &report : ctx->timing_result.clock_paths) {
+
+        critPathsJson.push_back(Json::object({{"from", clock_event_name(ctx, report.second.clock_pair.start)},
+                                              {"to", clock_event_name(ctx, report.second.clock_pair.end)},
+                                              {"path", report_critical_path(report.second)}}));
+    }
+
+    // Cross-domain paths
+    for (auto &report : ctx->timing_result.xclock_paths) {
+        critPathsJson.push_back(Json::object({{"from", clock_event_name(ctx, report.clock_pair.start)},
+                                              {"to", clock_event_name(ctx, report.clock_pair.end)},
+                                              {"path", report_critical_path(report)}}));
+    }
+
+    return critPathsJson;
+}
+
+static Json::array report_detailed_net_timings(const Context *ctx)
+{
+    auto detailedNetTimingsJson = Json::array();
+
+    // Detailed per-net timing analysis
+    for (const auto &it : ctx->timing_result.detailed_net_timings) {
+
+        const NetInfo *net = ctx->nets.at(it.first).get();
+        ClockEvent start = it.second[0].clock_pair.start;
+
+        Json::array endpointsJson;
+        for (const auto &sink_timing : it.second) {
+
+            // FIXME: Is it possible that there are multiple different start
+            // events for a single net? It has a single driver
+            NPNR_ASSERT(sink_timing.clock_pair.start == start);
+
+            auto endpointJson = Json::object({{"cell", sink_timing.cell_port.first.c_str(ctx)},
+                                              {"port", sink_timing.cell_port.second.c_str(ctx)},
+                                              {"event", clock_event_name(ctx, sink_timing.clock_pair.end)},
+                                              {"delay", ctx->getDelayNS(sink_timing.delay)},
+                                              {"budget", ctx->getDelayNS(sink_timing.budget)}});
+            endpointsJson.push_back(endpointJson);
+        }
+
+        auto netTimingJson = Json::object({{"net", net->name.c_str(ctx)},
+                                           {"driver", net->driver.cell->name.c_str(ctx)},
+                                           {"port", net->driver.port.c_str(ctx)},
+                                           {"event", clock_event_name(ctx, start)},
+                                           {"endpoints", endpointsJson}});
+
+        detailedNetTimingsJson.push_back(netTimingJson);
+    }
+
+    return detailedNetTimingsJson;
+}
+
+/*
+Report JSON structure:
+
+{
+  "utilization": {
+    <BEL name>: {
+      "available": <available count>,
+      "used": <used count>
+    },
+    ...
+  },
+  "fmax" {
+    <clock name>: {
+      "achieved": <achieved fmax [MHz]>,
+      "constraint": <target fmax [MHz]>
+    },
+    ...
+  },
+  "critical_paths": [
+    {
+      "from": <clock event edge and name>,
+      "to": <clock event edge and name>,
+      "path": [
+        {
+          "from": {
+            "cell": <driver cell name>
+            "port": <driver port name>
+            "loc": [
+              <grid x>,
+              <grid y>
+            ]
+          },
+          "to": {
+            "cell": <sink cell name>
+            "port": <sink port name>
+            "loc": [
+              <grid x>,
+              <grid y>
+            ]
+          },
+          "type": <path segment type "clk-to-q", "source", "logic", "routing" or "setup">,
+          "net": <net name (for routing only!)>,
+          "delay": <segment delay [ns]>,
+          "budget": <segment delay budget [ns] (for routing only!)>,
+        }
+        ...
+      ]
+    },
+    ...
+  ],
+  "detailed_net_timings": [
+    {
+      "driver": <driving cell name>,
+      "port": <driving cell port name>,
+      "event": <driver clock event name>,
+      "net": <net name>,
+      "endpoints": [
+        {
+          "cell": <sink cell name>,
+          "port": <sink cell port name>,
+          "event": <destination clock event name>,
+          "delay": <delay [ns]>,
+          "budget": <delay budget [ns]>,
+        }
+        ...
+      ]
+    }
+    ...
+  ]
+}
+*/
+
+void Context::writeReport(std::ostream &out) const
+{
+    auto util = get_utilization(this);
+    dict<std::string, Json> util_json;
+    for (const auto &kv : util) {
+        util_json[kv.first.str(this)] = Json::object{
+                {"used", kv.second.first},
+                {"available", kv.second.second},
+        };
+    }
+    dict<std::string, Json> fmax_json;
+    for (const auto &kv : timing_result.clock_fmax) {
+        fmax_json[kv.first.str(this)] = Json::object{
+                {"achieved", kv.second.achieved},
+                {"constraint", kv.second.constraint},
+        };
+    }
+
+    Json::object jsonRoot{
+            {"utilization", util_json}, {"fmax", fmax_json}, {"critical_paths", report_critical_paths(this)}};
+
+    if (detailed_timing_report) {
+        jsonRoot["detailed_net_timings"] = report_detailed_net_timings(this);
+    }
+
+    out << Json(jsonRoot).dump() << std::endl;
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/scope_lock.h b/common/kernel/scope_lock.h
new file mode 100644
index 00000000..2f0f767c
--- /dev/null
+++ b/common/kernel/scope_lock.h
@@ -0,0 +1,67 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2021 Symbiflow Authors.
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef SCOPE_LOCK_H
+#define SCOPE_LOCK_H
+
+#include <stdexcept>
+
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+// Provides a simple RAII locking object.  ScopeLock takes a lock when
+// constructed, and releases the lock on destruction or if "unlock_early" is
+// called.
+//
+// LockingObject must have a method "void lock(void)" and "void unlock(void)".
+template <typename LockingObject> class ScopeLock
+{
+  public:
+    ScopeLock(LockingObject *obj) : obj_(obj), locked_(false)
+    {
+        obj_->lock();
+        locked_ = true;
+    }
+    ScopeLock(const ScopeLock &other) = delete;
+    ScopeLock(const ScopeLock &&other) = delete;
+
+    ~ScopeLock()
+    {
+        if (locked_) {
+            obj_->unlock();
+        }
+    }
+    void unlock_early()
+    {
+        if (!locked_) {
+            throw std::runtime_error("Lock already released?");
+        }
+        locked_ = false;
+        obj_->unlock();
+    }
+
+  private:
+    LockingObject *obj_;
+    bool locked_;
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* SCOPE_LOCK_H */
diff --git a/common/kernel/sdf.cc b/common/kernel/sdf.cc
new file mode 100644
index 00000000..acff56ed
--- /dev/null
+++ b/common/kernel/sdf.cc
@@ -0,0 +1,334 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2019  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "nextpnr.h"
+#include "util.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+namespace SDF {
+
+struct MinMaxTyp
+{
+    double min, typ, max;
+};
+
+struct RiseFallDelay
+{
+    MinMaxTyp rise, fall;
+};
+
+struct PortAndEdge
+{
+    std::string port;
+    ClockEdge edge;
+};
+
+struct IOPath
+{
+    std::string from, to;
+    RiseFallDelay delay;
+};
+
+struct TimingCheck
+{
+    enum CheckType
+    {
+        SETUPHOLD,
+        PERIOD,
+        WIDTH
+    } type;
+    PortAndEdge from, to;
+    RiseFallDelay delay;
+};
+
+struct Cell
+{
+    std::string celltype, instance;
+    std::vector<IOPath> iopaths;
+    std::vector<TimingCheck> checks;
+};
+
+struct CellPort
+{
+    std::string cell, port;
+};
+
+struct Interconnect
+{
+    CellPort from, to;
+    RiseFallDelay delay;
+};
+
+struct SDFWriter
+{
+    bool cvc_mode = false;
+    std::vector<Cell> cells;
+    std::vector<Interconnect> conn;
+    std::string sdfversion, design, vendor, program;
+
+    std::string format_name(const std::string &name)
+    {
+        std::string fmt = "\"";
+        for (char c : name) {
+            if (c == '\\' || c == '\"')
+                fmt += "\"";
+            fmt += c;
+        }
+        fmt += "\"";
+        return fmt;
+    }
+
+    std::string escape_name(const std::string &name)
+    {
+        std::string esc;
+        for (char c : name) {
+            if (c == '$' || c == '\\' || c == '[' || c == ']' || c == ':' || (cvc_mode && c == '.'))
+                esc += '\\';
+            esc += c;
+        }
+        return esc;
+    }
+
+    std::string timing_check_name(TimingCheck::CheckType type)
+    {
+        switch (type) {
+        case TimingCheck::SETUPHOLD:
+            return "SETUPHOLD";
+        case TimingCheck::PERIOD:
+            return "PERIOD";
+        case TimingCheck::WIDTH:
+            return "WIDTH";
+        default:
+            NPNR_ASSERT_FALSE("unknown timing check type");
+        }
+    }
+
+    void write_delay(std::ostream &out, const RiseFallDelay &delay)
+    {
+        write_delay(out, delay.rise);
+        out << " ";
+        write_delay(out, delay.fall);
+    }
+
+    void write_delay(std::ostream &out, const MinMaxTyp &delay)
+    {
+        if (cvc_mode)
+            out << "(" << int(delay.min) << ":" << int(delay.typ) << ":" << int(delay.max) << ")";
+        else
+            out << "(" << delay.min << ":" << delay.typ << ":" << delay.max << ")";
+    }
+
+    void write_port(std::ostream &out, const CellPort &port)
+    {
+        if (cvc_mode)
+            out << escape_name(port.cell) + "." + escape_name(port.port);
+        else
+            out << escape_name(port.cell + "/" + port.port);
+    }
+
+    void write_portedge(std::ostream &out, const PortAndEdge &pe)
+    {
+        out << "(" << (pe.edge == RISING_EDGE ? "posedge" : "negedge") << " " << escape_name(pe.port) << ")";
+    }
+
+    void write(std::ostream &out)
+    {
+        out << "(DELAYFILE" << std::endl;
+        // Headers and  metadata
+        out << "  (SDFVERSION " << format_name(sdfversion) << ")" << std::endl;
+        out << "  (DESIGN " << format_name(design) << ")" << std::endl;
+        out << "  (VENDOR " << format_name(vendor) << ")" << std::endl;
+        out << "  (PROGRAM " << format_name(program) << ")" << std::endl;
+        out << "  (DIVIDER " << (cvc_mode ? "." : "/") << ")" << std::endl;
+        out << "  (TIMESCALE 1ps)" << std::endl;
+        // Write interconnect delays, with the main design begin a "cell"
+        out << "  (CELL" << std::endl;
+        out << "    (CELLTYPE " << format_name(design) << ")" << std::endl;
+        out << "    (INSTANCE )" << std::endl;
+        out << "    (DELAY" << std::endl;
+        out << "      (ABSOLUTE" << std::endl;
+        for (auto &ic : conn) {
+            out << "        (INTERCONNECT ";
+            write_port(out, ic.from);
+            out << " ";
+            write_port(out, ic.to);
+            out << " ";
+            write_delay(out, ic.delay);
+            out << ")" << std::endl;
+        }
+        out << "      )" << std::endl;
+        out << "    )" << std::endl;
+        out << "  )" << std::endl;
+        // Write cells
+        for (auto &cell : cells) {
+            out << "  (CELL" << std::endl;
+            out << "    (CELLTYPE " << format_name(cell.celltype) << ")" << std::endl;
+            out << "    (INSTANCE " << escape_name(cell.instance) << ")" << std::endl;
+            // IOPATHs (combinational delay and clock-to-q)
+            if (!cell.iopaths.empty()) {
+                out << "    (DELAY" << std::endl;
+                out << "      (ABSOLUTE" << std::endl;
+                for (auto &path : cell.iopaths) {
+                    out << "        (IOPATH " << escape_name(path.from) << " " << escape_name(path.to) << " ";
+                    write_delay(out, path.delay);
+                    out << ")" << std::endl;
+                }
+                out << "      )" << std::endl;
+                out << "    )" << std::endl;
+            }
+            // Timing Checks (setup/hold, period, width)
+            if (!cell.checks.empty()) {
+                out << "    (TIMINGCHECK" << std::endl;
+                for (auto &check : cell.checks) {
+                    out << "      (" << timing_check_name(check.type) << " ";
+                    write_portedge(out, check.from);
+                    out << " ";
+                    if (check.type == TimingCheck::SETUPHOLD) {
+                        write_portedge(out, check.to);
+                        out << " ";
+                    }
+                    if (check.type == TimingCheck::SETUPHOLD)
+                        write_delay(out, check.delay);
+                    else
+                        write_delay(out, check.delay.rise);
+                    out << ")" << std::endl;
+                }
+                out << "    )" << std::endl;
+            }
+            out << "    )" << std::endl;
+        }
+        out << ")" << std::endl;
+    }
+};
+
+} // namespace SDF
+
+void Context::writeSDF(std::ostream &out, bool cvc_mode) const
+{
+    using namespace SDF;
+    SDFWriter wr;
+    wr.cvc_mode = cvc_mode;
+    wr.design = str_or_default(attrs, id("module"), "top");
+    wr.sdfversion = "3.0";
+    wr.vendor = "nextpnr";
+    wr.program = "nextpnr";
+
+    const double delay_scale = 1000;
+    // Convert from DelayQuad to SDF-friendly RiseFallDelay
+    auto convert_delay = [&](const DelayQuad &dly) {
+        RiseFallDelay rf;
+        rf.rise.min = getDelayNS(dly.minRiseDelay()) * delay_scale;
+        rf.rise.typ = getDelayNS((dly.minRiseDelay() + dly.maxRiseDelay()) / 2) * delay_scale; // fixme: typ delays?
+        rf.rise.max = getDelayNS(dly.maxRiseDelay()) * delay_scale;
+        rf.fall.min = getDelayNS(dly.minFallDelay()) * delay_scale;
+        rf.fall.typ = getDelayNS((dly.minFallDelay() + dly.maxFallDelay()) / 2) * delay_scale; // fixme: typ delays?
+        rf.fall.max = getDelayNS(dly.maxFallDelay()) * delay_scale;
+        return rf;
+    };
+
+    auto convert_setuphold = [&](const DelayPair &setup, const DelayPair &hold) {
+        RiseFallDelay rf;
+        rf.rise.min = getDelayNS(setup.minDelay()) * delay_scale;
+        rf.rise.typ = getDelayNS((setup.minDelay() + setup.maxDelay()) / 2) * delay_scale; // fixme: typ delays?
+        rf.rise.max = getDelayNS(setup.maxDelay()) * delay_scale;
+        rf.fall.min = getDelayNS(hold.minDelay()) * delay_scale;
+        rf.fall.typ = getDelayNS((hold.minDelay() + hold.maxDelay()) / 2) * delay_scale; // fixme: typ delays?
+        rf.fall.max = getDelayNS(hold.maxDelay()) * delay_scale;
+        return rf;
+    };
+
+    for (const auto &cell : cells) {
+        Cell sc;
+        const CellInfo *ci = cell.second.get();
+        sc.instance = ci->name.str(this);
+        sc.celltype = ci->type.str(this);
+        for (auto port : ci->ports) {
+            int clockCount = 0;
+            TimingPortClass cls = getPortTimingClass(ci, port.first, clockCount);
+            if (cls == TMG_IGNORE)
+                continue;
+            if (port.second.net == nullptr)
+                continue; // Ignore disconnected ports
+            if (port.second.type != PORT_IN) {
+                // Add combinational paths to this output (or inout)
+                for (auto other : ci->ports) {
+                    if (other.second.net == nullptr)
+                        continue;
+                    if (other.second.type == PORT_OUT)
+                        continue;
+                    DelayQuad dly;
+                    if (!getCellDelay(ci, other.first, port.first, dly))
+                        continue;
+                    IOPath iop;
+                    iop.from = other.first.str(this);
+                    iop.to = port.first.str(this);
+                    iop.delay = convert_delay(dly);
+                    sc.iopaths.push_back(iop);
+                }
+                // Add clock-to-output delays, also as IOPaths
+                if (cls == TMG_REGISTER_OUTPUT)
+                    for (int i = 0; i < clockCount; i++) {
+                        auto clkInfo = getPortClockingInfo(ci, port.first, i);
+                        IOPath cqp;
+                        cqp.from = clkInfo.clock_port.str(this);
+                        cqp.to = port.first.str(this);
+                        cqp.delay = convert_delay(clkInfo.clockToQ);
+                        sc.iopaths.push_back(cqp);
+                    }
+            }
+            if (port.second.type != PORT_OUT && cls == TMG_REGISTER_INPUT) {
+                // Add setup/hold checks
+                for (int i = 0; i < clockCount; i++) {
+                    auto clkInfo = getPortClockingInfo(ci, port.first, i);
+                    TimingCheck chk;
+                    chk.from.edge = RISING_EDGE; // Add setup/hold checks equally for rising and falling edges
+                    chk.from.port = port.first.str(this);
+                    chk.to.edge = clkInfo.edge;
+                    chk.to.port = clkInfo.clock_port.str(this);
+                    chk.type = TimingCheck::SETUPHOLD;
+                    chk.delay = convert_setuphold(clkInfo.setup, clkInfo.hold);
+                    sc.checks.push_back(chk);
+                    chk.from.edge = FALLING_EDGE;
+                    sc.checks.push_back(chk);
+                }
+            }
+        }
+        wr.cells.push_back(sc);
+    }
+
+    for (auto &net : nets) {
+        NetInfo *ni = net.second.get();
+        if (ni->driver.cell == nullptr)
+            continue;
+        for (auto &usr : ni->users) {
+            Interconnect ic;
+            ic.from.cell = ni->driver.cell->name.str(this);
+            ic.from.port = ni->driver.port.str(this);
+            ic.to.cell = usr.cell->name.str(this);
+            ic.to.port = usr.port.str(this);
+            // FIXME: min/max routing delay
+            ic.delay = convert_delay(DelayQuad(getNetinfoRouteDelay(ni, usr)));
+            wr.conn.push_back(ic);
+        }
+    }
+    wr.write(out);
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/sso_array.h b/common/kernel/sso_array.h
new file mode 100644
index 00000000..80e7d1c1
--- /dev/null
+++ b/common/kernel/sso_array.h
@@ -0,0 +1,132 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef SSO_ARRAY_H
+#define SSO_ARRAY_H
+
+#include <cstdint>
+
+#include "nextpnr_assertions.h"
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+// An small size optimised array that is statically allocated when the size is N or less; heap allocated otherwise
+template <typename T, std::size_t N> class SSOArray
+{
+  private:
+    union
+    {
+        T data_static[N];
+        T *data_heap;
+    };
+    std::size_t m_size;
+    inline bool is_heap() const { return (m_size > N); }
+    void alloc()
+    {
+        if (is_heap()) {
+            data_heap = new T[m_size];
+        }
+    }
+
+  public:
+    T *data() { return is_heap() ? data_heap : data_static; }
+    const T *data() const { return is_heap() ? data_heap : data_static; }
+    std::size_t size() const { return m_size; }
+
+    T *begin() { return data(); }
+    T *end() { return data() + m_size; }
+    const T *begin() const { return data(); }
+    const T *end() const { return data() + m_size; }
+
+    SSOArray() : m_size(0){};
+
+    SSOArray(std::size_t size, const T &init = T()) : m_size(size)
+    {
+        alloc();
+        std::fill(begin(), end(), init);
+    }
+
+    SSOArray(const SSOArray &other) : m_size(other.size())
+    {
+        alloc();
+        std::copy(other.begin(), other.end(), begin());
+    }
+
+    SSOArray(SSOArray &&other) : m_size(other.size())
+    {
+        if (is_heap())
+            data_heap = other.data_heap;
+        else
+            std::copy(other.begin(), other.end(), begin());
+        other.m_size = 0;
+    }
+    SSOArray &operator=(const SSOArray &other)
+    {
+        if (&other == this)
+            return *this;
+        if (is_heap())
+            delete[] data_heap;
+        m_size = other.m_size;
+        alloc();
+        std::copy(other.begin(), other.end(), begin());
+        return *this;
+    }
+
+    template <typename Tother> SSOArray(const Tother &other) : m_size(other.size())
+    {
+        alloc();
+        std::copy(other.begin(), other.end(), begin());
+    }
+
+    ~SSOArray()
+    {
+        if (is_heap()) {
+            delete[] data_heap;
+        }
+    }
+
+    bool operator==(const SSOArray &other) const
+    {
+        if (size() != other.size())
+            return false;
+        return std::equal(begin(), end(), other.begin());
+    }
+    bool operator!=(const SSOArray &other) const
+    {
+        if (size() != other.size())
+            return true;
+        return !std::equal(begin(), end(), other.begin());
+    }
+    T &operator[](std::size_t idx)
+    {
+        NPNR_ASSERT(idx < m_size);
+        return data()[idx];
+    }
+    const T &operator[](std::size_t idx) const
+    {
+        NPNR_ASSERT(idx < m_size);
+        return data()[idx];
+    }
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/str_ring_buffer.cc b/common/kernel/str_ring_buffer.cc
new file mode 100644
index 00000000..443d8612
--- /dev/null
+++ b/common/kernel/str_ring_buffer.cc
@@ -0,0 +1,34 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "str_ring_buffer.h"
+
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+std::string &StrRingBuffer::next()
+{
+    std::string &s = buffer.at(index++);
+    if (index >= N)
+        index = 0;
+    return s;
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/str_ring_buffer.h b/common/kernel/str_ring_buffer.h
new file mode 100644
index 00000000..42583beb
--- /dev/null
+++ b/common/kernel/str_ring_buffer.h
@@ -0,0 +1,45 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Claire Xenia Wolf <claire@yosyshq.com>
+ *  Copyright (C) 2018  Serge Bazanski <q3k@q3k.org>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+#ifndef STR_RING_BUFFER_H
+#define STR_RING_BUFFER_H
+
+#include <array>
+#include <string>
+
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+// A ring buffer of strings, so we can return a simple const char * pointer for %s formatting - inspired by how logging
+// in Yosys works Let's just hope noone tries to log more than 100 things in one call....
+class StrRingBuffer
+{
+  private:
+    static const size_t N = 100;
+    std::array<std::string, N> buffer;
+    size_t index = 0;
+
+  public:
+    std::string &next();
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* STR_RING_BUFFER_H */
diff --git a/common/kernel/svg.cc b/common/kernel/svg.cc
new file mode 100644
index 00000000..c5e2ea36
--- /dev/null
+++ b/common/kernel/svg.cc
@@ -0,0 +1,152 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2020  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <boost/algorithm/string.hpp>
+#include <fstream>
+#include "log.h"
+#include "nextpnr.h"
+#include "util.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+namespace {
+struct SVGWriter
+{
+    const Context *ctx;
+    std::ostream &out;
+    float scale = 500.0;
+    bool hide_inactive = false;
+    SVGWriter(const Context *ctx, std::ostream &out) : ctx(ctx), out(out){};
+    const char *get_stroke_colour(GraphicElement::style_t style)
+    {
+        switch (style) {
+        case GraphicElement::STYLE_GRID:
+            return "#CCC";
+        case GraphicElement::STYLE_FRAME:
+            return "#808080";
+        case GraphicElement::STYLE_INACTIVE:
+            return "#C0C0C0";
+        case GraphicElement::STYLE_ACTIVE:
+            return "#FF3030";
+        default:
+            return "#000";
+        }
+    }
+
+    void write_decal(const DecalXY &dxy)
+    {
+        for (const auto &el : ctx->getDecalGraphics(dxy.decal)) {
+            if (el.style == GraphicElement::STYLE_HIDDEN ||
+                (hide_inactive && el.style == GraphicElement::STYLE_INACTIVE))
+                continue;
+            switch (el.type) {
+            case GraphicElement::TYPE_LINE:
+            case GraphicElement::TYPE_ARROW:
+            case GraphicElement::TYPE_LOCAL_LINE:
+            case GraphicElement::TYPE_LOCAL_ARROW:
+                out << stringf("<line x1=\"%f\" y1=\"%f\" x2=\"%f\" y2=\"%f\" stroke=\"%s\"/>", (el.x1 + dxy.x) * scale,
+                               (el.y1 + dxy.y) * scale, (el.x2 + dxy.x) * scale, (el.y2 + dxy.y) * scale,
+                               get_stroke_colour(el.style))
+                    << std::endl;
+                break;
+            case GraphicElement::TYPE_BOX:
+                out << stringf("<rect x=\"%f\" y=\"%f\" width=\"%f\" height=\"%f\" stroke=\"%s\" fill=\"%s\"/>",
+                               (el.x1 + dxy.x) * scale, (el.y1 + dxy.y) * scale, (el.x2 - el.x1) * scale,
+                               (el.y2 - el.y1) * scale, get_stroke_colour(el.style),
+                               el.style == GraphicElement::STYLE_ACTIVE ? "#FF8080" : "none")
+                    << std::endl;
+                break;
+            default:
+                break;
+            }
+        }
+    }
+
+    void operator()(const std::string &flags)
+    {
+        std::vector<std::string> options;
+        boost::algorithm::split(options, flags, boost::algorithm::is_space());
+        bool noroute = false;
+        for (const auto &opt : options) {
+            if (boost::algorithm::starts_with(opt, "scale=")) {
+                scale = float(std::stod(opt.substr(6)));
+                continue;
+            } else if (opt == "hide_routing") {
+                noroute = true;
+            } else if (opt == "hide_inactive") {
+                hide_inactive = true;
+            } else {
+                log_error("Unknown SVG option '%s'\n", opt.c_str());
+            }
+        }
+        float max_x = 0, max_y = 0;
+        for (auto group : ctx->getGroups()) {
+            auto decal = ctx->getGroupDecal(group);
+            for (auto el : ctx->getDecalGraphics(decal.decal)) {
+                max_x = std::max(max_x, decal.x + el.x1 + 1);
+                max_y = std::max(max_y, decal.y + el.y1 + 1);
+            }
+        }
+        for (auto bel : ctx->getBels()) {
+            auto decal = ctx->getBelDecal(bel);
+            for (auto el : ctx->getDecalGraphics(decal.decal)) {
+                max_x = std::max(max_x, decal.x + el.x1 + 1);
+                max_y = std::max(max_y, decal.y + el.y1 + 1);
+            }
+        }
+        for (auto wire : ctx->getWires()) {
+            auto decal = ctx->getWireDecal(wire);
+            for (auto el : ctx->getDecalGraphics(decal.decal)) {
+                max_x = std::max(max_x, decal.x + el.x1 + 1);
+                max_y = std::max(max_y, decal.y + el.y1 + 1);
+            }
+        }
+        for (auto pip : ctx->getPips()) {
+            auto decal = ctx->getPipDecal(pip);
+            for (auto el : ctx->getDecalGraphics(decal.decal)) {
+                max_x = std::max(max_x, decal.x + el.x1 + 1);
+                max_y = std::max(max_y, decal.y + el.y1 + 1);
+            }
+        }
+        out << "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>" << std::endl;
+        out << stringf("<svg viewBox=\"0 0 %f %f\" width=\"%f\" height=\"%f\" xmlns=\"http://www.w3.org/2000/svg\">",
+                       max_x * scale, max_y * scale, max_x * scale, max_y * scale)
+            << std::endl;
+        out << "<rect x=\"0\" y=\"0\" width=\"100%\" height=\"100%\" stroke=\"#fff\" fill=\"#fff\"/>" << std::endl;
+        for (auto group : ctx->getGroups())
+            write_decal(ctx->getGroupDecal(group));
+        for (auto bel : ctx->getBels())
+            write_decal(ctx->getBelDecal(bel));
+        if (!noroute) {
+            for (auto wire : ctx->getWires())
+                write_decal(ctx->getWireDecal(wire));
+            for (auto pip : ctx->getPips())
+                write_decal(ctx->getPipDecal(pip));
+        }
+        out << "</svg>" << std::endl;
+    }
+};
+} // namespace
+
+void Context::writeSVG(const std::string &filename, const std::string &flags) const
+{
+    std::ofstream out(filename);
+    SVGWriter(this, out)(flags);
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/timing.cc b/common/kernel/timing.cc
new file mode 100644
index 00000000..834785fb
--- /dev/null
+++ b/common/kernel/timing.cc
@@ -0,0 +1,1515 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  gatecat <gatecat@ds0.me>
+ *  Copyright (C) 2018  Eddie Hung <eddieh@ece.ubc.ca>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "timing.h"
+#include <algorithm>
+#include <boost/range/adaptor/reversed.hpp>
+#include <deque>
+#include <map>
+#include <utility>
+#include "log.h"
+#include "util.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+void TimingAnalyser::setup()
+{
+    init_ports();
+    get_cell_delays();
+    topo_sort();
+    setup_port_domains();
+    run();
+}
+
+void TimingAnalyser::run(bool update_route_delays)
+{
+    reset_times();
+    if (update_route_delays)
+        get_route_delays();
+    walk_forward();
+    walk_backward();
+    compute_slack();
+    compute_criticality();
+}
+
+void TimingAnalyser::init_ports()
+{
+    // Per cell port structures
+    for (auto &cell : ctx->cells) {
+        CellInfo *ci = cell.second.get();
+        for (auto &port : ci->ports) {
+            auto &data = ports[CellPortKey(ci->name, port.first)];
+            data.type = port.second.type;
+            data.cell_port = CellPortKey(ci->name, port.first);
+        }
+    }
+}
+
+void TimingAnalyser::get_cell_delays()
+{
+    for (auto &port : ports) {
+        CellInfo *ci = cell_info(port.first);
+        auto &pi = port_info(port.first);
+        auto &pd = port.second;
+
+        IdString name = port.first.port;
+        // Ignore dangling ports altogether for timing purposes
+        if (!pi.net)
+            continue;
+        pd.cell_arcs.clear();
+        int clkInfoCount = 0;
+        TimingPortClass cls = ctx->getPortTimingClass(ci, name, clkInfoCount);
+        if (cls == TMG_STARTPOINT || cls == TMG_ENDPOINT || cls == TMG_CLOCK_INPUT || cls == TMG_GEN_CLOCK ||
+            cls == TMG_IGNORE)
+            continue;
+        if (pi.type == PORT_IN) {
+            // Input ports might have setup/hold relationships
+            if (cls == TMG_REGISTER_INPUT) {
+                for (int i = 0; i < clkInfoCount; i++) {
+                    auto info = ctx->getPortClockingInfo(ci, name, i);
+                    if (!ci->ports.count(info.clock_port) || ci->ports.at(info.clock_port).net == nullptr)
+                        continue;
+                    pd.cell_arcs.emplace_back(CellArc::SETUP, info.clock_port, DelayQuad(info.setup, info.setup),
+                                              info.edge);
+                    pd.cell_arcs.emplace_back(CellArc::HOLD, info.clock_port, DelayQuad(info.hold, info.hold),
+                                              info.edge);
+                }
+            }
+            // Combinational delays through cell
+            for (auto &other_port : ci->ports) {
+                auto &op = other_port.second;
+                // ignore dangling ports and non-outputs
+                if (op.net == nullptr || op.type != PORT_OUT)
+                    continue;
+                DelayQuad delay;
+                bool is_path = ctx->getCellDelay(ci, name, other_port.first, delay);
+                if (is_path)
+                    pd.cell_arcs.emplace_back(CellArc::COMBINATIONAL, other_port.first, delay);
+            }
+        } else if (pi.type == PORT_OUT) {
+            // Output ports might have clk-to-q relationships
+            if (cls == TMG_REGISTER_OUTPUT) {
+                for (int i = 0; i < clkInfoCount; i++) {
+                    auto info = ctx->getPortClockingInfo(ci, name, i);
+                    if (!ci->ports.count(info.clock_port) || ci->ports.at(info.clock_port).net == nullptr)
+                        continue;
+                    pd.cell_arcs.emplace_back(CellArc::CLK_TO_Q, info.clock_port, info.clockToQ, info.edge);
+                }
+            }
+            // Combinational delays through cell
+            for (auto &other_port : ci->ports) {
+                auto &op = other_port.second;
+                // ignore dangling ports and non-inputs
+                if (op.net == nullptr || op.type != PORT_IN)
+                    continue;
+                DelayQuad delay;
+                bool is_path = ctx->getCellDelay(ci, other_port.first, name, delay);
+                if (is_path)
+                    pd.cell_arcs.emplace_back(CellArc::COMBINATIONAL, other_port.first, delay);
+            }
+        }
+    }
+}
+
+void TimingAnalyser::get_route_delays()
+{
+    for (auto &net : ctx->nets) {
+        NetInfo *ni = net.second.get();
+        if (ni->driver.cell == nullptr || ni->driver.cell->bel == BelId())
+            continue;
+        for (auto &usr : ni->users) {
+            if (usr.cell->bel == BelId())
+                continue;
+            ports.at(CellPortKey(usr)).route_delay = DelayPair(ctx->getNetinfoRouteDelay(ni, usr));
+        }
+    }
+}
+
+void TimingAnalyser::set_route_delay(CellPortKey port, DelayPair value) { ports.at(port).route_delay = value; }
+
+void TimingAnalyser::topo_sort()
+{
+    TopoSort<CellPortKey> topo;
+    for (auto &port : ports) {
+        auto &pd = port.second;
+        // All ports are nodes
+        topo.node(port.first);
+        if (pd.type == PORT_IN) {
+            // inputs: combinational arcs through the cell are edges
+            for (auto &arc : pd.cell_arcs) {
+                if (arc.type != CellArc::COMBINATIONAL)
+                    continue;
+                topo.edge(port.first, CellPortKey(port.first.cell, arc.other_port));
+            }
+        } else if (pd.type == PORT_OUT) {
+            // output: routing arcs are edges
+            const NetInfo *pn = port_info(port.first).net;
+            if (pn != nullptr) {
+                for (auto &usr : pn->users)
+                    topo.edge(port.first, CellPortKey(usr));
+            }
+        }
+    }
+    bool no_loops = topo.sort();
+    if (!no_loops && verbose_mode) {
+        log_info("Found %d combinational loops:\n", int(topo.loops.size()));
+        int i = 0;
+        for (auto &loop : topo.loops) {
+            log_info("    loop %d:\n", ++i);
+            for (auto &port : loop) {
+                log_info("        %s.%s (%s)\n", ctx->nameOf(port.cell), ctx->nameOf(port.port),
+                         ctx->nameOf(port_info(port).net));
+            }
+        }
+    }
+    have_loops = !no_loops;
+    std::swap(topological_order, topo.sorted);
+}
+
+void TimingAnalyser::setup_port_domains()
+{
+    for (auto &d : domains) {
+        d.startpoints.clear();
+        d.endpoints.clear();
+    }
+    // Go forward through the topological order (domains from the PoV of arrival time)
+    bool first_iter = true;
+    do {
+        updated_domains = false;
+        for (auto port : topological_order) {
+            auto &pd = ports.at(port);
+            auto &pi = port_info(port);
+            if (pi.type == PORT_OUT) {
+                if (first_iter) {
+                    for (auto &fanin : pd.cell_arcs) {
+                        if (fanin.type != CellArc::CLK_TO_Q)
+                            continue;
+                        // registered outputs are startpoints
+                        auto dom = domain_id(port.cell, fanin.other_port, fanin.edge);
+                        // create per-domain data
+                        pd.arrival[dom];
+                        domains.at(dom).startpoints.emplace_back(port, fanin.other_port);
+                    }
+                }
+                // copy domains across routing
+                if (pi.net != nullptr)
+                    for (auto &usr : pi.net->users)
+                        copy_domains(port, CellPortKey(usr), false);
+            } else {
+                // copy domains from input to output
+                for (auto &fanout : pd.cell_arcs) {
+                    if (fanout.type != CellArc::COMBINATIONAL)
+                        continue;
+                    copy_domains(port, CellPortKey(port.cell, fanout.other_port), false);
+                }
+            }
+        }
+        // Go backward through the topological order (domains from the PoV of required time)
+        for (auto port : reversed_range(topological_order)) {
+            auto &pd = ports.at(port);
+            auto &pi = port_info(port);
+            if (pi.type == PORT_OUT) {
+                // copy domains from output to input
+                for (auto &fanin : pd.cell_arcs) {
+                    if (fanin.type != CellArc::COMBINATIONAL)
+                        continue;
+                    copy_domains(port, CellPortKey(port.cell, fanin.other_port), true);
+                }
+            } else {
+                if (first_iter) {
+                    for (auto &fanout : pd.cell_arcs) {
+                        if (fanout.type != CellArc::SETUP)
+                            continue;
+                        // registered inputs are endpoints
+                        auto dom = domain_id(port.cell, fanout.other_port, fanout.edge);
+                        // create per-domain data
+                        pd.required[dom];
+                        domains.at(dom).endpoints.emplace_back(port, fanout.other_port);
+                    }
+                }
+                // copy port to driver
+                if (pi.net != nullptr && pi.net->driver.cell != nullptr)
+                    copy_domains(port, CellPortKey(pi.net->driver), true);
+            }
+        }
+        // Iterate over ports and find domain paris
+        for (auto port : topological_order) {
+            auto &pd = ports.at(port);
+            for (auto &arr : pd.arrival)
+                for (auto &req : pd.required) {
+                    pd.domain_pairs[domain_pair_id(arr.first, req.first)];
+                }
+        }
+        first_iter = false;
+        // If there are loops, repeat the process until a fixed point is reached, as there might be unusual ways to
+        // visit points, which would result in a missing domain key and therefore crash later on
+    } while (have_loops && updated_domains);
+    for (auto &dp : domain_pairs) {
+        auto &launch_data = domains.at(dp.key.launch);
+        auto &capture_data = domains.at(dp.key.capture);
+        if (launch_data.key.clock != capture_data.key.clock)
+            continue;
+        IdString clk = launch_data.key.clock;
+        delay_t period = ctx->getDelayFromNS(1.0e9 / ctx->setting<float>("target_freq"));
+        if (ctx->nets.count(clk)) {
+            NetInfo *clk_net = ctx->nets.at(clk).get();
+            if (clk_net->clkconstr) {
+                period = clk_net->clkconstr->period.minDelay();
+            }
+        }
+        if (launch_data.key.edge != capture_data.key.edge)
+            period /= 2;
+        dp.period = DelayPair(period);
+    }
+}
+
+void TimingAnalyser::reset_times()
+{
+    for (auto &port : ports) {
+        auto do_reset = [&](dict<domain_id_t, ArrivReqTime> &times) {
+            for (auto &t : times) {
+                t.second.value = init_delay;
+                t.second.path_length = 0;
+                t.second.bwd_min = CellPortKey();
+                t.second.bwd_max = CellPortKey();
+            }
+        };
+        do_reset(port.second.arrival);
+        do_reset(port.second.required);
+        for (auto &dp : port.second.domain_pairs) {
+            dp.second.setup_slack = std::numeric_limits<delay_t>::max();
+            dp.second.hold_slack = std::numeric_limits<delay_t>::max();
+            dp.second.max_path_length = 0;
+            dp.second.criticality = 0;
+            dp.second.budget = 0;
+        }
+        port.second.worst_crit = 0;
+        port.second.worst_setup_slack = std::numeric_limits<delay_t>::max();
+        port.second.worst_hold_slack = std::numeric_limits<delay_t>::max();
+    }
+}
+
+void TimingAnalyser::set_arrival_time(CellPortKey target, domain_id_t domain, DelayPair arrival, int path_length,
+                                      CellPortKey prev)
+{
+    auto &arr = ports.at(target).arrival.at(domain);
+    if (arrival.max_delay > arr.value.max_delay) {
+        arr.value.max_delay = arrival.max_delay;
+        arr.bwd_max = prev;
+    }
+    if (!setup_only && (arrival.min_delay < arr.value.min_delay)) {
+        arr.value.min_delay = arrival.min_delay;
+        arr.bwd_min = prev;
+    }
+    arr.path_length = std::max(arr.path_length, path_length);
+}
+
+void TimingAnalyser::set_required_time(CellPortKey target, domain_id_t domain, DelayPair required, int path_length,
+                                       CellPortKey prev)
+{
+    auto &req = ports.at(target).required.at(domain);
+    if (required.min_delay < req.value.min_delay) {
+        req.value.min_delay = required.min_delay;
+        req.bwd_min = prev;
+    }
+    if (!setup_only && (required.max_delay > req.value.max_delay)) {
+        req.value.max_delay = required.max_delay;
+        req.bwd_max = prev;
+    }
+    req.path_length = std::max(req.path_length, path_length);
+}
+
+void TimingAnalyser::walk_forward()
+{
+    // Assign initial arrival time to domain startpoints
+    for (domain_id_t dom_id = 0; dom_id < domain_id_t(domains.size()); ++dom_id) {
+        auto &dom = domains.at(dom_id);
+        for (auto &sp : dom.startpoints) {
+            auto &pd = ports.at(sp.first);
+            DelayPair init_arrival(0);
+            CellPortKey clock_key;
+            // TODO: clock routing delay, if analysis of that is enabled
+            if (sp.second != IdString()) {
+                // clocked startpoints have a clock-to-out time
+                for (auto &fanin : pd.cell_arcs) {
+                    if (fanin.type == CellArc::CLK_TO_Q && fanin.other_port == sp.second) {
+                        init_arrival = init_arrival + fanin.value.delayPair();
+                        break;
+                    }
+                }
+                clock_key = CellPortKey(sp.first.cell, sp.second);
+            }
+            set_arrival_time(sp.first, dom_id, init_arrival, 1, clock_key);
+        }
+    }
+    // Walk forward in topological order
+    for (auto p : topological_order) {
+        auto &pd = ports.at(p);
+        for (auto &arr : pd.arrival) {
+            if (pd.type == PORT_OUT) {
+                // Output port: propagate delay through net, adding route delay
+                NetInfo *net = port_info(p).net;
+                if (net != nullptr)
+                    for (auto &usr : net->users) {
+                        CellPortKey usr_key(usr);
+                        auto &usr_pd = ports.at(usr_key);
+                        set_arrival_time(usr_key, arr.first, arr.second.value + usr_pd.route_delay,
+                                         arr.second.path_length, p);
+                    }
+            } else if (pd.type == PORT_IN) {
+                // Input port; propagate delay through cell, adding combinational delay
+                for (auto &fanout : pd.cell_arcs) {
+                    if (fanout.type != CellArc::COMBINATIONAL)
+                        continue;
+                    set_arrival_time(CellPortKey(p.cell, fanout.other_port), arr.first,
+                                     arr.second.value + fanout.value.delayPair(), arr.second.path_length + 1, p);
+                }
+            }
+        }
+    }
+}
+
+void TimingAnalyser::walk_backward()
+{
+    // Assign initial required time to domain endpoints
+    // Note that clock frequency will be considered later in the analysis for, for now all required times are normalised
+    // to 0ns
+    for (domain_id_t dom_id = 0; dom_id < domain_id_t(domains.size()); ++dom_id) {
+        auto &dom = domains.at(dom_id);
+        for (auto &ep : dom.endpoints) {
+            auto &pd = ports.at(ep.first);
+            DelayPair init_setuphold(0);
+            CellPortKey clock_key;
+            // TODO: clock routing delay, if analysis of that is enabled
+            if (ep.second != IdString()) {
+                // Add setup/hold time, if this endpoint is clocked
+                for (auto &fanin : pd.cell_arcs) {
+                    if (fanin.type == CellArc::SETUP && fanin.other_port == ep.second)
+                        init_setuphold.min_delay -= fanin.value.maxDelay();
+                    if (fanin.type == CellArc::HOLD && fanin.other_port == ep.second)
+                        init_setuphold.max_delay -= fanin.value.maxDelay();
+                }
+                clock_key = CellPortKey(ep.first.cell, ep.second);
+            }
+            set_required_time(ep.first, dom_id, init_setuphold, 1, clock_key);
+        }
+    }
+    // Walk backwards in topological order
+    for (auto p : reversed_range(topological_order)) {
+        auto &pd = ports.at(p);
+        for (auto &req : pd.required) {
+            if (pd.type == PORT_IN) {
+                // Input port: propagate delay back through net, subtracting route delay
+                NetInfo *net = port_info(p).net;
+                if (net != nullptr && net->driver.cell != nullptr)
+                    set_required_time(CellPortKey(net->driver), req.first,
+                                      req.second.value - DelayPair(pd.route_delay.maxDelay()), req.second.path_length,
+                                      p);
+            } else if (pd.type == PORT_OUT) {
+                // Output port : propagate delay back through cell, subtracting combinational delay
+                for (auto &fanin : pd.cell_arcs) {
+                    if (fanin.type != CellArc::COMBINATIONAL)
+                        continue;
+                    set_required_time(CellPortKey(p.cell, fanin.other_port), req.first,
+                                      req.second.value - DelayPair(fanin.value.maxDelay()), req.second.path_length + 1,
+                                      p);
+                }
+            }
+        }
+    }
+}
+
+void TimingAnalyser::print_fmax()
+{
+    // Temporary testing code for comparison only
+    dict<int, double> domain_fmax;
+    for (auto p : topological_order) {
+        auto &pd = ports.at(p);
+        for (auto &req : pd.required) {
+            if (pd.arrival.count(req.first)) {
+                auto &arr = pd.arrival.at(req.first);
+                double fmax = 1000.0 / ctx->getDelayNS(arr.value.maxDelay() - req.second.value.minDelay());
+                if (!domain_fmax.count(req.first) || domain_fmax.at(req.first) > fmax)
+                    domain_fmax[req.first] = fmax;
+            }
+        }
+    }
+    for (auto &fm : domain_fmax) {
+        log_info("Domain %s Worst Fmax %.02f\n", ctx->nameOf(domains.at(fm.first).key.clock), fm.second);
+    }
+}
+
+void TimingAnalyser::compute_slack()
+{
+    for (auto &dp : domain_pairs) {
+        dp.worst_setup_slack = std::numeric_limits<delay_t>::max();
+        dp.worst_hold_slack = std::numeric_limits<delay_t>::max();
+    }
+    for (auto p : topological_order) {
+        auto &pd = ports.at(p);
+        for (auto &pdp : pd.domain_pairs) {
+            auto &dp = domain_pairs.at(pdp.first);
+            auto &arr = pd.arrival.at(dp.key.launch);
+            auto &req = pd.required.at(dp.key.capture);
+            pdp.second.setup_slack = 0 - (arr.value.maxDelay() - req.value.minDelay());
+            if (!setup_only)
+                pdp.second.hold_slack = arr.value.minDelay() - req.value.maxDelay();
+            pdp.second.max_path_length = arr.path_length + req.path_length;
+            if (dp.key.launch == dp.key.capture)
+                pd.worst_setup_slack = std::min(pd.worst_setup_slack, dp.period.minDelay() + pdp.second.setup_slack);
+            dp.worst_setup_slack = std::min(dp.worst_setup_slack, pdp.second.setup_slack);
+            if (!setup_only) {
+                pd.worst_hold_slack = std::min(pd.worst_hold_slack, pdp.second.hold_slack);
+                dp.worst_hold_slack = std::min(dp.worst_hold_slack, pdp.second.hold_slack);
+            }
+        }
+    }
+}
+
+void TimingAnalyser::compute_criticality()
+{
+    for (auto p : topological_order) {
+        auto &pd = ports.at(p);
+        for (auto &pdp : pd.domain_pairs) {
+            auto &dp = domain_pairs.at(pdp.first);
+            float crit =
+                    1.0f - (float(pdp.second.setup_slack) - float(dp.worst_setup_slack)) / float(-dp.worst_setup_slack);
+            crit = std::min(crit, 1.0f);
+            crit = std::max(crit, 0.0f);
+            pdp.second.criticality = crit;
+            pd.worst_crit = std::max(pd.worst_crit, crit);
+        }
+    }
+}
+
+std::vector<CellPortKey> TimingAnalyser::get_failing_eps(domain_id_t domain_pair, int count)
+{
+    std::vector<CellPortKey> failing_eps;
+    delay_t last_slack = std::numeric_limits<delay_t>::min();
+    auto &dp = domain_pairs.at(domain_pair);
+    auto &cap_d = domains.at(dp.key.capture);
+    while (int(failing_eps.size()) < count) {
+        CellPortKey next;
+        delay_t next_slack = std::numeric_limits<delay_t>::max();
+        for (auto ep : cap_d.endpoints) {
+            auto &pd = ports.at(ep.first);
+            if (!pd.domain_pairs.count(domain_pair))
+                continue;
+            delay_t ep_slack = pd.domain_pairs.at(domain_pair).setup_slack;
+            if (ep_slack < next_slack && ep_slack > last_slack) {
+                next = ep.first;
+                next_slack = ep_slack;
+            }
+        }
+        if (next == CellPortKey())
+            break;
+        failing_eps.push_back(next);
+        last_slack = next_slack;
+    }
+    return failing_eps;
+}
+
+void TimingAnalyser::print_critical_path(CellPortKey endpoint, domain_id_t domain_pair)
+{
+    CellPortKey cursor = endpoint;
+    auto &dp = domain_pairs.at(domain_pair);
+    log("    endpoint %s.%s (slack %.02fns):\n", ctx->nameOf(cursor.cell), ctx->nameOf(cursor.port),
+        ctx->getDelayNS(ports.at(cursor).domain_pairs.at(domain_pair).setup_slack));
+    while (cursor != CellPortKey()) {
+        log("        %s.%s (net %s)\n", ctx->nameOf(cursor.cell), ctx->nameOf(cursor.port),
+            ctx->nameOf(get_net_or_empty(ctx->cells.at(cursor.cell).get(), cursor.port)));
+        if (!ports.at(cursor).arrival.count(dp.key.launch))
+            break;
+        cursor = ports.at(cursor).arrival.at(dp.key.launch).bwd_max;
+    }
+}
+
+namespace {
+const char *edge_name(ClockEdge edge) { return (edge == FALLING_EDGE) ? "negedge" : "posedge"; }
+} // namespace
+
+void TimingAnalyser::print_report()
+{
+    for (int i = 0; i < int(domain_pairs.size()); i++) {
+        auto &dp = domain_pairs.at(i);
+        auto &launch = domains.at(dp.key.launch);
+        auto &capture = domains.at(dp.key.capture);
+        log("Worst endpoints for %s %s -> %s %s\n", edge_name(launch.key.edge), ctx->nameOf(launch.key.clock),
+            edge_name(capture.key.edge), ctx->nameOf(capture.key.clock));
+        auto failing_eps = get_failing_eps(i, 5);
+        for (auto &ep : failing_eps)
+            print_critical_path(ep, i);
+        log_break();
+    }
+}
+
+domain_id_t TimingAnalyser::domain_id(IdString cell, IdString clock_port, ClockEdge edge)
+{
+    return domain_id(ctx->cells.at(cell)->ports.at(clock_port).net, edge);
+}
+domain_id_t TimingAnalyser::domain_id(const NetInfo *net, ClockEdge edge)
+{
+    NPNR_ASSERT(net != nullptr);
+    ClockDomainKey key{net->name, edge};
+    auto inserted = domain_to_id.emplace(key, domains.size());
+    if (inserted.second) {
+        domains.emplace_back(key);
+    }
+    return inserted.first->second;
+}
+domain_id_t TimingAnalyser::domain_pair_id(domain_id_t launch, domain_id_t capture)
+{
+    ClockDomainPairKey key{launch, capture};
+    auto inserted = pair_to_id.emplace(key, domain_pairs.size());
+    if (inserted.second) {
+        domain_pairs.emplace_back(key);
+    }
+    return inserted.first->second;
+}
+
+void TimingAnalyser::copy_domains(const CellPortKey &from, const CellPortKey &to, bool backward)
+{
+    auto &f = ports.at(from), &t = ports.at(to);
+    for (auto &dom : (backward ? f.required : f.arrival)) {
+        updated_domains |= (backward ? t.required : t.arrival).emplace(dom.first, ArrivReqTime{}).second;
+    }
+}
+
+CellInfo *TimingAnalyser::cell_info(const CellPortKey &key) { return ctx->cells.at(key.cell).get(); }
+
+PortInfo &TimingAnalyser::port_info(const CellPortKey &key) { return ctx->cells.at(key.cell)->ports.at(key.port); }
+
+/** LEGACY CODE BEGIN **/
+
+typedef std::vector<const PortRef *> PortRefVector;
+typedef std::map<int, unsigned> DelayFrequency;
+
+struct CriticalPathData
+{
+    PortRefVector ports;
+    delay_t path_delay;
+    delay_t path_period;
+};
+
+typedef dict<ClockPair, CriticalPathData> CriticalPathDataMap;
+
+typedef dict<IdString, std::vector<NetSinkTiming>> DetailedNetTimings;
+
+struct Timing
+{
+    Context *ctx;
+    bool net_delays;
+    bool update;
+    delay_t min_slack;
+    CriticalPathDataMap *crit_path;
+    DelayFrequency *slack_histogram;
+    DetailedNetTimings *detailed_net_timings;
+    IdString async_clock;
+
+    struct TimingData
+    {
+        TimingData() : max_arrival(), max_path_length(), min_remaining_budget() {}
+        TimingData(delay_t max_arrival) : max_arrival(max_arrival), max_path_length(), min_remaining_budget() {}
+        delay_t max_arrival;
+        unsigned max_path_length = 0;
+        delay_t min_remaining_budget;
+        bool false_startpoint = false;
+        std::vector<delay_t> min_required;
+        dict<ClockEvent, delay_t> arrival_time;
+    };
+
+    Timing(Context *ctx, bool net_delays, bool update, CriticalPathDataMap *crit_path = nullptr,
+           DelayFrequency *slack_histogram = nullptr, DetailedNetTimings *detailed_net_timings = nullptr)
+            : ctx(ctx), net_delays(net_delays), update(update), min_slack(1.0e12 / ctx->setting<float>("target_freq")),
+              crit_path(crit_path), slack_histogram(slack_histogram), detailed_net_timings(detailed_net_timings),
+              async_clock(ctx->id("$async$"))
+    {
+    }
+
+    delay_t walk_paths()
+    {
+        const auto clk_period = ctx->getDelayFromNS(1.0e9 / ctx->setting<float>("target_freq"));
+
+        // First, compute the topological order of nets to walk through the circuit, assuming it is a _acyclic_ graph
+        // TODO(eddieh): Handle the case where it is cyclic, e.g. combinatorial loops
+        std::vector<NetInfo *> topological_order;
+        dict<const NetInfo *, dict<ClockEvent, TimingData>, hash_ptr_ops> net_data;
+        // In lieu of deleting edges from the graph, simply count the number of fanins to each output port
+        dict<const PortInfo *, unsigned, hash_ptr_ops> port_fanin;
+
+        std::vector<IdString> input_ports;
+        std::vector<const PortInfo *> output_ports;
+
+        pool<IdString> ooc_port_nets;
+
+        // In out-of-context mode, top-level inputs look floating but aren't
+        if (bool_or_default(ctx->settings, ctx->id("arch.ooc"))) {
+            for (auto &p : ctx->ports) {
+                if (p.second.type != PORT_IN || p.second.net == nullptr)
+                    continue;
+                ooc_port_nets.insert(p.second.net->name);
+            }
+        }
+
+        for (auto &cell : ctx->cells) {
+            input_ports.clear();
+            output_ports.clear();
+            for (auto &port : cell.second->ports) {
+                if (!port.second.net)
+                    continue;
+                if (port.second.type == PORT_OUT)
+                    output_ports.push_back(&port.second);
+                else
+                    input_ports.push_back(port.first);
+            }
+
+            for (auto o : output_ports) {
+                int clocks = 0;
+                TimingPortClass portClass = ctx->getPortTimingClass(cell.second.get(), o->name, clocks);
+                // If output port is influenced by a clock (e.g. FF output) then add it to the ordering as a timing
+                // start-point
+                if (portClass == TMG_REGISTER_OUTPUT) {
+                    topological_order.emplace_back(o->net);
+                    for (int i = 0; i < clocks; i++) {
+                        TimingClockingInfo clkInfo = ctx->getPortClockingInfo(cell.second.get(), o->name, i);
+                        const NetInfo *clknet = get_net_or_empty(cell.second.get(), clkInfo.clock_port);
+                        IdString clksig = clknet ? clknet->name : async_clock;
+                        net_data[o->net][ClockEvent{clksig, clknet ? clkInfo.edge : RISING_EDGE}] =
+                                TimingData{clkInfo.clockToQ.maxDelay()};
+                    }
+
+                } else {
+                    if (portClass == TMG_STARTPOINT || portClass == TMG_GEN_CLOCK || portClass == TMG_IGNORE) {
+                        topological_order.emplace_back(o->net);
+                        TimingData td;
+                        td.false_startpoint = (portClass == TMG_GEN_CLOCK || portClass == TMG_IGNORE);
+                        td.max_arrival = 0;
+                        net_data[o->net][ClockEvent{async_clock, RISING_EDGE}] = td;
+                    }
+
+                    // Don't analyse paths from a clock input to other pins - they will be considered by the
+                    // special-case handling register input/output class ports
+                    if (portClass == TMG_CLOCK_INPUT)
+                        continue;
+
+                    // Otherwise, for all driven input ports on this cell, if a timing arc exists between the input and
+                    // the current output port, increment fanin counter
+                    for (auto i : input_ports) {
+                        DelayQuad comb_delay;
+                        NetInfo *i_net = cell.second->ports[i].net;
+                        if (i_net->driver.cell == nullptr && !ooc_port_nets.count(i_net->name))
+                            continue;
+                        bool is_path = ctx->getCellDelay(cell.second.get(), i, o->name, comb_delay);
+                        if (is_path)
+                            port_fanin[o]++;
+                    }
+                    // If there is no fanin, add the port as a false startpoint
+                    if (!port_fanin.count(o) && !net_data.count(o->net)) {
+                        topological_order.emplace_back(o->net);
+                        TimingData td;
+                        td.false_startpoint = true;
+                        td.max_arrival = 0;
+                        net_data[o->net][ClockEvent{async_clock, RISING_EDGE}] = td;
+                    }
+                }
+            }
+        }
+
+        // In out-of-context mode, handle top-level ports correctly
+        if (bool_or_default(ctx->settings, ctx->id("arch.ooc"))) {
+            for (auto &p : ctx->ports) {
+                if (p.second.type != PORT_IN || p.second.net == nullptr)
+                    continue;
+                topological_order.emplace_back(p.second.net);
+            }
+        }
+
+        std::deque<NetInfo *> queue(topological_order.begin(), topological_order.end());
+        // Now walk the design, from the start points identified previously, building up a topological order
+        while (!queue.empty()) {
+            const auto net = queue.front();
+            queue.pop_front();
+
+            for (auto &usr : net->users) {
+                int user_clocks;
+                TimingPortClass usrClass = ctx->getPortTimingClass(usr.cell, usr.port, user_clocks);
+                if (usrClass == TMG_IGNORE || usrClass == TMG_CLOCK_INPUT)
+                    continue;
+                for (auto &port : usr.cell->ports) {
+                    if (port.second.type != PORT_OUT || !port.second.net)
+                        continue;
+                    int port_clocks;
+                    TimingPortClass portClass = ctx->getPortTimingClass(usr.cell, port.first, port_clocks);
+
+                    // Skip if this is a clocked output (but allow non-clocked ones)
+                    if (portClass == TMG_REGISTER_OUTPUT || portClass == TMG_STARTPOINT || portClass == TMG_IGNORE ||
+                        portClass == TMG_GEN_CLOCK)
+                        continue;
+                    DelayQuad comb_delay;
+                    bool is_path = ctx->getCellDelay(usr.cell, usr.port, port.first, comb_delay);
+                    if (!is_path)
+                        continue;
+                    // Decrement the fanin count, and only add to topological order if all its fanins have already
+                    // been visited
+                    auto it = port_fanin.find(&port.second);
+                    if (it == port_fanin.end())
+                        log_error("Timing counted negative fanin count for port %s.%s (net %s), please report this "
+                                  "error.\n",
+                                  ctx->nameOf(usr.cell), ctx->nameOf(port.first), ctx->nameOf(port.second.net));
+                    if (--it->second == 0) {
+                        topological_order.emplace_back(port.second.net);
+                        queue.emplace_back(port.second.net);
+                        port_fanin.erase(it);
+                    }
+                }
+            }
+        }
+
+        // Sanity check to ensure that all ports where fanins were recorded were indeed visited
+        if (!port_fanin.empty() && !bool_or_default(ctx->settings, ctx->id("timing/ignoreLoops"), false)) {
+            for (auto fanin : port_fanin) {
+                NetInfo *net = fanin.first->net;
+                if (net != nullptr) {
+                    log_info("   remaining fanin includes %s (net %s)\n", fanin.first->name.c_str(ctx),
+                             net->name.c_str(ctx));
+                    if (net->driver.cell != nullptr)
+                        log_info("        driver = %s.%s\n", net->driver.cell->name.c_str(ctx),
+                                 net->driver.port.c_str(ctx));
+                    for (auto net_user : net->users)
+                        log_info("        user: %s.%s\n", net_user.cell->name.c_str(ctx), net_user.port.c_str(ctx));
+                } else {
+                    log_info("   remaining fanin includes %s (no net)\n", fanin.first->name.c_str(ctx));
+                }
+            }
+            if (ctx->force)
+                log_warning("timing analysis failed due to presence of combinatorial loops, incomplete specification "
+                            "of timing ports, etc.\n");
+            else
+                log_error("timing analysis failed due to presence of combinatorial loops, incomplete specification of "
+                          "timing ports, etc.\n");
+        }
+
+        // Go forwards topologically to find the maximum arrival time and max path length for each net
+        std::vector<ClockEvent> startdomains;
+        for (auto net : topological_order) {
+            if (!net_data.count(net))
+                continue;
+            // Updates later on might invalidate a reference taken here to net_data, so iterate over a list of domains
+            // instead
+            startdomains.clear();
+            {
+                auto &nd_map = net_data.at(net);
+                for (auto &startdomain : nd_map)
+                    startdomains.push_back(startdomain.first);
+            }
+            for (auto &start_clk : startdomains) {
+                auto &nd = net_data.at(net).at(start_clk);
+                if (nd.false_startpoint)
+                    continue;
+                const auto net_arrival = nd.max_arrival;
+                const auto net_length_plus_one = nd.max_path_length + 1;
+                nd.min_remaining_budget = clk_period;
+                for (auto &usr : net->users) {
+                    int port_clocks;
+                    TimingPortClass portClass = ctx->getPortTimingClass(usr.cell, usr.port, port_clocks);
+                    auto net_delay = net_delays ? ctx->getNetinfoRouteDelay(net, usr) : delay_t();
+                    auto usr_arrival = net_arrival + net_delay;
+
+                    if (portClass == TMG_ENDPOINT || portClass == TMG_IGNORE || portClass == TMG_CLOCK_INPUT) {
+                        // Skip
+                    } else {
+                        auto budget_override = ctx->getBudgetOverride(net, usr, net_delay);
+                        // Iterate over all output ports on the same cell as the sink
+                        for (auto port : usr.cell->ports) {
+                            if (port.second.type != PORT_OUT || !port.second.net)
+                                continue;
+                            DelayQuad comb_delay;
+                            // Look up delay through this path
+                            bool is_path = ctx->getCellDelay(usr.cell, usr.port, port.first, comb_delay);
+                            if (!is_path)
+                                continue;
+                            auto &data = net_data[port.second.net][start_clk];
+                            auto &arrival = data.max_arrival;
+                            arrival = std::max(arrival, usr_arrival + comb_delay.maxDelay());
+                            if (!budget_override) { // Do not increment path length if budget overridden since it
+                                                    // doesn't
+                                // require a share of the slack
+                                auto &path_length = data.max_path_length;
+                                path_length = std::max(path_length, net_length_plus_one);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        dict<ClockPair, std::pair<delay_t, NetInfo *>> crit_nets;
+
+        // Now go backwards topologically to determine the minimum path slack, and to distribute all path slack evenly
+        // between all nets on the path
+        for (auto net : boost::adaptors::reverse(topological_order)) {
+            if (!net_data.count(net))
+                continue;
+            auto &nd_map = net_data.at(net);
+            for (auto &startdomain : nd_map) {
+                auto &nd = startdomain.second;
+                // Ignore false startpoints
+                if (nd.false_startpoint)
+                    continue;
+                const delay_t net_length_plus_one = nd.max_path_length + 1;
+                auto &net_min_remaining_budget = nd.min_remaining_budget;
+                for (auto &usr : net->users) {
+                    auto net_delay = net_delays ? ctx->getNetinfoRouteDelay(net, usr) : delay_t();
+                    auto budget_override = ctx->getBudgetOverride(net, usr, net_delay);
+                    int port_clocks;
+                    TimingPortClass portClass = ctx->getPortTimingClass(usr.cell, usr.port, port_clocks);
+                    if (portClass == TMG_REGISTER_INPUT || portClass == TMG_ENDPOINT) {
+                        auto process_endpoint = [&](IdString clksig, ClockEdge edge, delay_t setup) {
+                            const auto net_arrival = nd.max_arrival;
+                            const auto endpoint_arrival = net_arrival + net_delay + setup;
+                            delay_t period;
+                            // Set default period
+                            if (edge == startdomain.first.edge) {
+                                period = clk_period;
+                            } else {
+                                period = clk_period / 2;
+                            }
+                            if (clksig != async_clock) {
+                                if (ctx->nets.at(clksig)->clkconstr) {
+                                    if (edge == startdomain.first.edge) {
+                                        // same edge
+                                        period = ctx->nets.at(clksig)->clkconstr->period.minDelay();
+                                    } else if (edge == RISING_EDGE) {
+                                        // falling -> rising
+                                        period = ctx->nets.at(clksig)->clkconstr->low.minDelay();
+                                    } else if (edge == FALLING_EDGE) {
+                                        // rising -> falling
+                                        period = ctx->nets.at(clksig)->clkconstr->high.minDelay();
+                                    }
+                                }
+                            }
+                            auto path_budget = period - endpoint_arrival;
+
+                            if (update) {
+                                auto budget_share = budget_override ? 0 : path_budget / net_length_plus_one;
+                                usr.budget = std::min(usr.budget, net_delay + budget_share);
+                                net_min_remaining_budget =
+                                        std::min(net_min_remaining_budget, path_budget - budget_share);
+                            }
+
+                            if (path_budget < min_slack)
+                                min_slack = path_budget;
+
+                            if (slack_histogram) {
+                                int slack_ps = ctx->getDelayNS(path_budget) * 1000;
+                                (*slack_histogram)[slack_ps]++;
+                            }
+                            ClockEvent dest_ev{clksig, edge};
+                            ClockPair clockPair{startdomain.first, dest_ev};
+                            nd.arrival_time[dest_ev] = std::max(nd.arrival_time[dest_ev], endpoint_arrival);
+
+                            // Store the detailed timing for each net and user (a.k.a. sink)
+                            if (detailed_net_timings) {
+                                NetSinkTiming sink_timing;
+                                sink_timing.clock_pair = clockPair;
+                                sink_timing.cell_port = std::make_pair(usr.cell->name, usr.port);
+                                sink_timing.delay = endpoint_arrival;
+                                sink_timing.budget = period;
+
+                                (*detailed_net_timings)[net->name].push_back(sink_timing);
+                            }
+
+                            if (crit_path) {
+                                if (!crit_nets.count(clockPair) || crit_nets.at(clockPair).first < endpoint_arrival) {
+                                    crit_nets[clockPair] = std::make_pair(endpoint_arrival, net);
+                                    (*crit_path)[clockPair].path_delay = endpoint_arrival;
+                                    (*crit_path)[clockPair].path_period = period;
+                                    (*crit_path)[clockPair].ports.clear();
+                                    (*crit_path)[clockPair].ports.push_back(&usr);
+                                }
+                            }
+                        };
+                        if (portClass == TMG_REGISTER_INPUT) {
+                            for (int i = 0; i < port_clocks; i++) {
+                                TimingClockingInfo clkInfo = ctx->getPortClockingInfo(usr.cell, usr.port, i);
+                                const NetInfo *clknet = get_net_or_empty(usr.cell, clkInfo.clock_port);
+                                IdString clksig = clknet ? clknet->name : async_clock;
+                                process_endpoint(clksig, clknet ? clkInfo.edge : RISING_EDGE, clkInfo.setup.maxDelay());
+                            }
+                        } else {
+                            process_endpoint(async_clock, RISING_EDGE, 0);
+                        }
+
+                    } else if (update) {
+
+                        // Iterate over all output ports on the same cell as the sink
+                        for (const auto &port : usr.cell->ports) {
+                            if (port.second.type != PORT_OUT || !port.second.net)
+                                continue;
+                            DelayQuad comb_delay;
+                            bool is_path = ctx->getCellDelay(usr.cell, usr.port, port.first, comb_delay);
+                            if (!is_path)
+                                continue;
+                            if (net_data.count(port.second.net) &&
+                                net_data.at(port.second.net).count(startdomain.first)) {
+                                auto path_budget =
+                                        net_data.at(port.second.net).at(startdomain.first).min_remaining_budget;
+                                auto budget_share = budget_override ? 0 : path_budget / net_length_plus_one;
+                                usr.budget = std::min(usr.budget, net_delay + budget_share);
+                                net_min_remaining_budget =
+                                        std::min(net_min_remaining_budget, path_budget - budget_share);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        if (crit_path) {
+            // Walk backwards from the most critical net
+            for (auto crit_pair : crit_nets) {
+                NetInfo *crit_net = crit_pair.second.second;
+                auto &cp_ports = (*crit_path)[crit_pair.first].ports;
+                while (crit_net) {
+                    const PortInfo *crit_ipin = nullptr;
+                    delay_t max_arrival = std::numeric_limits<delay_t>::min();
+                    // Look at all input ports on its driving cell
+                    for (const auto &port : crit_net->driver.cell->ports) {
+                        if (port.second.type != PORT_IN || !port.second.net)
+                            continue;
+                        DelayQuad comb_delay;
+                        bool is_path =
+                                ctx->getCellDelay(crit_net->driver.cell, port.first, crit_net->driver.port, comb_delay);
+                        if (!is_path)
+                            continue;
+                        // If input port is influenced by a clock, skip
+                        int port_clocks;
+                        TimingPortClass portClass =
+                                ctx->getPortTimingClass(crit_net->driver.cell, port.first, port_clocks);
+                        if (portClass == TMG_CLOCK_INPUT || portClass == TMG_ENDPOINT || portClass == TMG_IGNORE)
+                            continue;
+                        // And find the fanin net with the latest arrival time
+                        if (net_data.count(port.second.net) &&
+                            net_data.at(port.second.net).count(crit_pair.first.start)) {
+                            auto net_arrival = net_data.at(port.second.net).at(crit_pair.first.start).max_arrival;
+                            if (net_delays) {
+                                for (auto &user : port.second.net->users)
+                                    if (user.port == port.first && user.cell == crit_net->driver.cell) {
+                                        net_arrival += ctx->getNetinfoRouteDelay(port.second.net, user);
+                                        break;
+                                    }
+                            }
+                            net_arrival += comb_delay.maxDelay();
+                            if (net_arrival > max_arrival) {
+                                max_arrival = net_arrival;
+                                crit_ipin = &port.second;
+                            }
+                        }
+                    }
+
+                    if (!crit_ipin)
+                        break;
+                    // Now convert PortInfo* into a PortRef*
+                    for (auto &usr : crit_ipin->net->users) {
+                        if (usr.cell->name == crit_net->driver.cell->name && usr.port == crit_ipin->name) {
+                            cp_ports.push_back(&usr);
+                            break;
+                        }
+                    }
+                    crit_net = crit_ipin->net;
+                }
+                std::reverse(cp_ports.begin(), cp_ports.end());
+            }
+        }
+        return min_slack;
+    }
+
+    void assign_budget()
+    {
+        // Clear delays to a very high value first
+        for (auto &net : ctx->nets) {
+            for (auto &usr : net.second->users) {
+                usr.budget = std::numeric_limits<delay_t>::max();
+            }
+        }
+
+        walk_paths();
+    }
+};
+
+void assign_budget(Context *ctx, bool quiet)
+{
+    if (!quiet) {
+        log_break();
+        log_info("Annotating ports with timing budgets for target frequency %.2f MHz\n",
+                 ctx->setting<float>("target_freq") / 1e6);
+    }
+
+    Timing timing(ctx, ctx->setting<int>("slack_redist_iter") > 0 /* net_delays */, true /* update */);
+    timing.assign_budget();
+
+    if (!quiet || ctx->verbose) {
+        for (auto &net : ctx->nets) {
+            for (auto &user : net.second->users) {
+                // Post-update check
+                if (!ctx->setting<bool>("auto_freq") && user.budget < 0)
+                    log_info("port %s.%s, connected to net '%s', has negative "
+                             "timing budget of %fns\n",
+                             user.cell->name.c_str(ctx), user.port.c_str(ctx), net.first.c_str(ctx),
+                             ctx->getDelayNS(user.budget));
+                else if (ctx->debug)
+                    log_info("port %s.%s, connected to net '%s', has "
+                             "timing budget of %fns\n",
+                             user.cell->name.c_str(ctx), user.port.c_str(ctx), net.first.c_str(ctx),
+                             ctx->getDelayNS(user.budget));
+            }
+        }
+    }
+
+    // For slack redistribution, if user has not specified a frequency dynamically adjust the target frequency to be the
+    // currently achieved maximum
+    if (ctx->setting<bool>("auto_freq") && ctx->setting<int>("slack_redist_iter") > 0) {
+        delay_t default_slack = delay_t((1.0e9 / ctx->getDelayNS(1)) / ctx->setting<float>("target_freq"));
+        ctx->settings[ctx->id("target_freq")] =
+                std::to_string(1.0e9 / ctx->getDelayNS(default_slack - timing.min_slack));
+        if (ctx->verbose)
+            log_info("minimum slack for this assign = %.2f ns, target Fmax for next "
+                     "update = %.2f MHz\n",
+                     ctx->getDelayNS(timing.min_slack), ctx->setting<float>("target_freq") / 1e6);
+    }
+
+    if (!quiet)
+        log_info("Checksum: 0x%08x\n", ctx->checksum());
+}
+
+CriticalPath build_critical_path_report(Context *ctx, ClockPair &clocks, const PortRefVector &crit_path)
+{
+
+    CriticalPath report;
+    report.clock_pair = clocks;
+
+    auto &front = crit_path.front();
+    auto &front_port = front->cell->ports.at(front->port);
+    auto &front_driver = front_port.net->driver;
+
+    int port_clocks;
+    auto portClass = ctx->getPortTimingClass(front_driver.cell, front_driver.port, port_clocks);
+
+    const CellInfo *last_cell = front->cell;
+    IdString last_port = front_driver.port;
+
+    int clock_start = -1;
+    if (portClass == TMG_REGISTER_OUTPUT) {
+        for (int i = 0; i < port_clocks; i++) {
+            TimingClockingInfo clockInfo = ctx->getPortClockingInfo(front_driver.cell, front_driver.port, i);
+            const NetInfo *clknet = get_net_or_empty(front_driver.cell, clockInfo.clock_port);
+            if (clknet != nullptr && clknet->name == clocks.start.clock && clockInfo.edge == clocks.start.edge) {
+                last_port = clockInfo.clock_port;
+                clock_start = i;
+                break;
+            }
+        }
+    }
+
+    for (auto sink : crit_path) {
+        auto sink_cell = sink->cell;
+        auto &port = sink_cell->ports.at(sink->port);
+        auto net = port.net;
+        auto &driver = net->driver;
+        auto driver_cell = driver.cell;
+
+        CriticalPath::Segment seg_logic;
+
+        DelayQuad comb_delay;
+        if (clock_start != -1) {
+            auto clockInfo = ctx->getPortClockingInfo(driver_cell, driver.port, clock_start);
+            comb_delay = clockInfo.clockToQ;
+            clock_start = -1;
+            seg_logic.type = CriticalPath::Segment::Type::CLK_TO_Q;
+        } else if (last_port == driver.port) {
+            // Case where we start with a STARTPOINT etc
+            comb_delay = DelayQuad(0);
+            seg_logic.type = CriticalPath::Segment::Type::SOURCE;
+        } else {
+            ctx->getCellDelay(driver_cell, last_port, driver.port, comb_delay);
+            seg_logic.type = CriticalPath::Segment::Type::LOGIC;
+        }
+
+        seg_logic.delay = comb_delay.maxDelay();
+        seg_logic.budget = 0;
+        seg_logic.from = std::make_pair(last_cell->name, last_port);
+        seg_logic.to = std::make_pair(driver_cell->name, driver.port);
+        seg_logic.net = IdString();
+        report.segments.push_back(seg_logic);
+
+        auto net_delay = ctx->getNetinfoRouteDelay(net, *sink);
+
+        CriticalPath::Segment seg_route;
+        seg_route.type = CriticalPath::Segment::Type::ROUTING;
+        seg_route.delay = net_delay;
+        seg_route.budget = sink->budget;
+        seg_route.from = std::make_pair(driver_cell->name, driver.port);
+        seg_route.to = std::make_pair(sink_cell->name, sink->port);
+        seg_route.net = net->name;
+        report.segments.push_back(seg_route);
+
+        last_cell = sink_cell;
+        last_port = sink->port;
+    }
+
+    int clockCount = 0;
+    auto sinkClass = ctx->getPortTimingClass(crit_path.back()->cell, crit_path.back()->port, clockCount);
+    if (sinkClass == TMG_REGISTER_INPUT && clockCount > 0) {
+        auto sinkClockInfo = ctx->getPortClockingInfo(crit_path.back()->cell, crit_path.back()->port, 0);
+        delay_t setup = sinkClockInfo.setup.maxDelay();
+
+        CriticalPath::Segment seg_logic;
+        seg_logic.type = CriticalPath::Segment::Type::SETUP;
+        seg_logic.delay = setup;
+        seg_logic.budget = 0;
+        seg_logic.from = std::make_pair(last_cell->name, last_port);
+        seg_logic.to = seg_logic.from;
+        seg_logic.net = IdString();
+        report.segments.push_back(seg_logic);
+    }
+
+    return report;
+}
+
+void timing_analysis(Context *ctx, bool print_histogram, bool print_fmax, bool print_path, bool warn_on_failure,
+                     bool update_results)
+{
+    auto format_event = [ctx](const ClockEvent &e, int field_width = 0) {
+        std::string value;
+        if (e.clock == ctx->id("$async$"))
+            value = std::string("<async>");
+        else
+            value = (e.edge == FALLING_EDGE ? std::string("negedge ") : std::string("posedge ")) + e.clock.str(ctx);
+        if (int(value.length()) < field_width)
+            value.insert(value.length(), field_width - int(value.length()), ' ');
+        return value;
+    };
+
+    CriticalPathDataMap crit_paths;
+    DelayFrequency slack_histogram;
+    DetailedNetTimings detailed_net_timings;
+
+    Timing timing(ctx, true /* net_delays */, false /* update */, (print_path || print_fmax) ? &crit_paths : nullptr,
+                  print_histogram ? &slack_histogram : nullptr,
+                  (update_results && ctx->detailed_timing_report) ? &detailed_net_timings : nullptr);
+    timing.walk_paths();
+
+    bool report_critical_paths = print_path || print_fmax || update_results;
+
+    dict<IdString, CriticalPath> clock_reports;
+    std::vector<CriticalPath> xclock_reports;
+    dict<IdString, ClockFmax> clock_fmax;
+    std::set<IdString> empty_clocks; // set of clocks with no interior paths
+
+    if (report_critical_paths) {
+
+        for (auto path : crit_paths) {
+            const ClockEvent &a = path.first.start;
+            const ClockEvent &b = path.first.end;
+            empty_clocks.insert(a.clock);
+            empty_clocks.insert(b.clock);
+        }
+        for (auto path : crit_paths) {
+            const ClockEvent &a = path.first.start;
+            const ClockEvent &b = path.first.end;
+            if (a.clock != b.clock || a.clock == ctx->id("$async$"))
+                continue;
+            double Fmax;
+            empty_clocks.erase(a.clock);
+            if (a.edge == b.edge)
+                Fmax = 1000 / ctx->getDelayNS(path.second.path_delay);
+            else
+                Fmax = 500 / ctx->getDelayNS(path.second.path_delay);
+            if (!clock_fmax.count(a.clock) || Fmax < clock_fmax.at(a.clock).achieved) {
+                clock_fmax[a.clock].achieved = Fmax;
+                clock_fmax[a.clock].constraint = 0.0f; // Will be filled later
+                clock_reports[a.clock] = build_critical_path_report(ctx, path.first, path.second.ports);
+                clock_reports[a.clock].period = path.second.path_period;
+            }
+        }
+
+        for (auto &path : crit_paths) {
+            const ClockEvent &a = path.first.start;
+            const ClockEvent &b = path.first.end;
+            if (a.clock == b.clock && a.clock != ctx->id("$async$"))
+                continue;
+
+            auto &crit_path = crit_paths.at(path.first).ports;
+            xclock_reports.push_back(build_critical_path_report(ctx, path.first, crit_path));
+            xclock_reports.back().period = path.second.path_period;
+        }
+
+        if (clock_reports.empty()) {
+            log_info("No Fmax available; no interior timing paths found in design.\n");
+        }
+
+        std::sort(xclock_reports.begin(), xclock_reports.end(), [ctx](const CriticalPath &ra, const CriticalPath &rb) {
+            const auto &a = ra.clock_pair;
+            const auto &b = rb.clock_pair;
+
+            if (a.start.clock.str(ctx) < b.start.clock.str(ctx))
+                return true;
+            if (a.start.clock.str(ctx) > b.start.clock.str(ctx))
+                return false;
+            if (a.start.edge < b.start.edge)
+                return true;
+            if (a.start.edge > b.start.edge)
+                return false;
+            if (a.end.clock.str(ctx) < b.end.clock.str(ctx))
+                return true;
+            if (a.end.clock.str(ctx) > b.end.clock.str(ctx))
+                return false;
+            if (a.end.edge < b.end.edge)
+                return true;
+            return false;
+        });
+
+        for (auto &clock : clock_reports) {
+            float target = ctx->setting<float>("target_freq") / 1e6;
+            if (ctx->nets.at(clock.first)->clkconstr)
+                target = 1000 / ctx->getDelayNS(ctx->nets.at(clock.first)->clkconstr->period.minDelay());
+            clock_fmax[clock.first].constraint = target;
+        }
+    }
+
+    // Print critical paths
+    if (print_path) {
+
+        static auto print_net_source = [ctx](const NetInfo *net) {
+            // Check if this net is annotated with a source list
+            auto sources = net->attrs.find(ctx->id("src"));
+            if (sources == net->attrs.end()) {
+                // No sources for this net, can't print anything
+                return;
+            }
+
+            // Sources are separated by pipe characters.
+            // There is no guaranteed ordering on sources, so we just print all
+            auto sourcelist = sources->second.as_string();
+            std::vector<std::string> source_entries;
+            size_t current = 0, prev = 0;
+            while ((current = sourcelist.find("|", prev)) != std::string::npos) {
+                source_entries.emplace_back(sourcelist.substr(prev, current - prev));
+                prev = current + 1;
+            }
+            // Ensure we emplace the final entry
+            source_entries.emplace_back(sourcelist.substr(prev, current - prev));
+
+            // Iterate and print our source list at the correct indentation level
+            log_info("               Defined in:\n");
+            for (auto entry : source_entries) {
+                log_info("                 %s\n", entry.c_str());
+            }
+        };
+
+        // A helper function for reporting one critical path
+        auto print_path_report = [ctx](const CriticalPath &path) {
+            delay_t total = 0, logic_total = 0, route_total = 0;
+
+            log_info("curr total\n");
+            for (const auto &segment : path.segments) {
+
+                total += segment.delay;
+
+                if (segment.type == CriticalPath::Segment::Type::CLK_TO_Q ||
+                    segment.type == CriticalPath::Segment::Type::SOURCE ||
+                    segment.type == CriticalPath::Segment::Type::LOGIC ||
+                    segment.type == CriticalPath::Segment::Type::SETUP) {
+                    logic_total += segment.delay;
+
+                    const std::string type_name =
+                            (segment.type == CriticalPath::Segment::Type::SETUP) ? "Setup" : "Source";
+
+                    log_info("%4.1f %4.1f  %s %s.%s\n", ctx->getDelayNS(segment.delay), ctx->getDelayNS(total),
+                             type_name.c_str(), segment.to.first.c_str(ctx), segment.to.second.c_str(ctx));
+                } else if (segment.type == CriticalPath::Segment::Type::ROUTING) {
+                    route_total += segment.delay;
+
+                    const auto &driver = ctx->cells.at(segment.from.first);
+                    const auto &sink = ctx->cells.at(segment.to.first);
+
+                    auto driver_loc = ctx->getBelLocation(driver->bel);
+                    auto sink_loc = ctx->getBelLocation(sink->bel);
+
+                    log_info("%4.1f %4.1f    Net %s budget %f ns (%d,%d) -> (%d,%d)\n", ctx->getDelayNS(segment.delay),
+                             ctx->getDelayNS(total), segment.net.c_str(ctx), ctx->getDelayNS(segment.budget),
+                             driver_loc.x, driver_loc.y, sink_loc.x, sink_loc.y);
+                    log_info("               Sink %s.%s\n", segment.to.first.c_str(ctx), segment.to.second.c_str(ctx));
+
+                    const NetInfo *net = ctx->nets.at(segment.net).get();
+
+                    if (ctx->verbose) {
+
+                        PortRef sink_ref;
+                        sink_ref.cell = sink.get();
+                        sink_ref.port = segment.to.second;
+                        sink_ref.budget = segment.budget;
+
+                        auto driver_wire = ctx->getNetinfoSourceWire(net);
+                        auto sink_wire = ctx->getNetinfoSinkWire(net, sink_ref, 0);
+                        log_info("                 prediction: %f ns estimate: %f ns\n",
+                                 ctx->getDelayNS(ctx->predictArcDelay(net, sink_ref)),
+                                 ctx->getDelayNS(ctx->estimateDelay(driver_wire, sink_wire)));
+                        auto cursor = sink_wire;
+                        delay_t delay;
+                        while (driver_wire != cursor) {
+#ifdef ARCH_ECP5
+                            if (net->is_global)
+                                break;
+#endif
+                            auto it = net->wires.find(cursor);
+                            assert(it != net->wires.end());
+                            auto pip = it->second.pip;
+                            NPNR_ASSERT(pip != PipId());
+                            delay = ctx->getPipDelay(pip).maxDelay();
+                            log_info("                 %1.3f %s\n", ctx->getDelayNS(delay), ctx->nameOfPip(pip));
+                            cursor = ctx->getPipSrcWire(pip);
+                        }
+                    }
+
+                    if (!ctx->disable_critical_path_source_print) {
+                        print_net_source(net);
+                    }
+                }
+            }
+            log_info("%.1f ns logic, %.1f ns routing\n", ctx->getDelayNS(logic_total), ctx->getDelayNS(route_total));
+        };
+
+        // Single domain paths
+        for (auto &clock : clock_reports) {
+            log_break();
+            std::string start = clock.second.clock_pair.start.edge == FALLING_EDGE ? std::string("negedge")
+                                                                                   : std::string("posedge");
+            std::string end =
+                    clock.second.clock_pair.end.edge == FALLING_EDGE ? std::string("negedge") : std::string("posedge");
+            log_info("Critical path report for clock '%s' (%s -> %s):\n", clock.first.c_str(ctx), start.c_str(),
+                     end.c_str());
+            auto &report = clock.second;
+            print_path_report(report);
+        }
+
+        // Cross-domain paths
+        for (auto &report : xclock_reports) {
+            log_break();
+            std::string start = format_event(report.clock_pair.start);
+            std::string end = format_event(report.clock_pair.end);
+            log_info("Critical path report for cross-domain path '%s' -> '%s':\n", start.c_str(), end.c_str());
+            print_path_report(report);
+        }
+    }
+
+    if (print_fmax) {
+        log_break();
+
+        unsigned max_width = 0;
+        for (auto &clock : clock_reports)
+            max_width = std::max<unsigned>(max_width, clock.first.str(ctx).size());
+
+        for (auto &clock : clock_reports) {
+            const auto &clock_name = clock.first.str(ctx);
+            const int width = max_width - clock_name.size();
+
+            float fmax = clock_fmax[clock.first].achieved;
+            float target = clock_fmax[clock.first].constraint;
+            bool passed = target < fmax;
+
+            if (!warn_on_failure || passed)
+                log_info("Max frequency for clock %*s'%s': %.02f MHz (%s at %.02f MHz)\n", width, "",
+                         clock_name.c_str(), fmax, passed ? "PASS" : "FAIL", target);
+            else if (bool_or_default(ctx->settings, ctx->id("timing/allowFail"), false))
+                log_warning("Max frequency for clock %*s'%s': %.02f MHz (%s at %.02f MHz)\n", width, "",
+                            clock_name.c_str(), fmax, passed ? "PASS" : "FAIL", target);
+            else
+                log_nonfatal_error("Max frequency for clock %*s'%s': %.02f MHz (%s at %.02f MHz)\n", width, "",
+                                   clock_name.c_str(), fmax, passed ? "PASS" : "FAIL", target);
+        }
+        for (auto &eclock : empty_clocks) {
+            if (eclock != ctx->id("$async$"))
+                log_info("Clock '%s' has no interior paths\n", eclock.c_str(ctx));
+        }
+        log_break();
+
+        int start_field_width = 0, end_field_width = 0;
+        for (auto &report : xclock_reports) {
+            start_field_width = std::max((int)format_event(report.clock_pair.start).length(), start_field_width);
+            end_field_width = std::max((int)format_event(report.clock_pair.end).length(), end_field_width);
+        }
+
+        for (auto &report : xclock_reports) {
+            const ClockEvent &a = report.clock_pair.start;
+            const ClockEvent &b = report.clock_pair.end;
+            delay_t path_delay = 0;
+            for (const auto &segment : report.segments) {
+                path_delay += segment.delay;
+            }
+            auto ev_a = format_event(a, start_field_width), ev_b = format_event(b, end_field_width);
+            log_info("Max delay %s -> %s: %0.02f ns\n", ev_a.c_str(), ev_b.c_str(), ctx->getDelayNS(path_delay));
+        }
+        log_break();
+    }
+
+    if (print_histogram && slack_histogram.size() > 0) {
+        unsigned num_bins = 20;
+        unsigned bar_width = 60;
+        auto min_slack = slack_histogram.begin()->first;
+        auto max_slack = slack_histogram.rbegin()->first;
+        auto bin_size = std::max<unsigned>(1, ceil((max_slack - min_slack + 1) / float(num_bins)));
+        std::vector<unsigned> bins(num_bins);
+        unsigned max_freq = 0;
+        for (const auto &i : slack_histogram) {
+            int bin_idx = int((i.first - min_slack) / bin_size);
+            if (bin_idx < 0)
+                bin_idx = 0;
+            else if (bin_idx >= int(num_bins))
+                bin_idx = num_bins - 1;
+            auto &bin = bins.at(bin_idx);
+            bin += i.second;
+            max_freq = std::max(max_freq, bin);
+        }
+        bar_width = std::min(bar_width, max_freq);
+
+        log_break();
+        log_info("Slack histogram:\n");
+        log_info(" legend: * represents %d endpoint(s)\n", max_freq / bar_width);
+        log_info("         + represents [1,%d) endpoint(s)\n", max_freq / bar_width);
+        for (unsigned i = 0; i < num_bins; ++i)
+            log_info("[%6d, %6d) |%s%c\n", min_slack + bin_size * i, min_slack + bin_size * (i + 1),
+                     std::string(bins[i] * bar_width / max_freq, '*').c_str(),
+                     (bins[i] * bar_width) % max_freq > 0 ? '+' : ' ');
+    }
+
+    // Update timing results in the context
+    if (update_results) {
+        auto &results = ctx->timing_result;
+
+        results.clock_fmax = std::move(clock_fmax);
+        results.clock_paths = std::move(clock_reports);
+        results.xclock_paths = std::move(xclock_reports);
+
+        results.detailed_net_timings = std::move(detailed_net_timings);
+    }
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/kernel/timing.h b/common/kernel/timing.h
new file mode 100644
index 00000000..fe1bcaa8
--- /dev/null
+++ b/common/kernel/timing.h
@@ -0,0 +1,236 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef TIMING_H
+#define TIMING_H
+
+#include "nextpnr.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct CellPortKey
+{
+    CellPortKey(){};
+    CellPortKey(IdString cell, IdString port) : cell(cell), port(port){};
+    explicit CellPortKey(const PortRef &pr)
+    {
+        NPNR_ASSERT(pr.cell != nullptr);
+        cell = pr.cell->name;
+        port = pr.port;
+    }
+    IdString cell, port;
+    unsigned int hash() const { return mkhash(cell.hash(), port.hash()); }
+    inline bool operator==(const CellPortKey &other) const { return (cell == other.cell) && (port == other.port); }
+    inline bool operator!=(const CellPortKey &other) const { return (cell != other.cell) || (port != other.port); }
+    inline bool operator<(const CellPortKey &other) const
+    {
+        return cell == other.cell ? port < other.port : cell < other.cell;
+    }
+};
+
+struct ClockDomainKey
+{
+    IdString clock;
+    ClockEdge edge;
+    ClockDomainKey(IdString clock_net, ClockEdge edge) : clock(clock_net), edge(edge){};
+    // probably also need something here to deal with constraints
+    inline bool is_async() const { return clock == IdString(); }
+
+    unsigned int hash() const { return mkhash(clock.hash(), int(edge)); }
+
+    inline bool operator==(const ClockDomainKey &other) const { return (clock == other.clock) && (edge == other.edge); }
+};
+
+typedef int domain_id_t;
+
+struct ClockDomainPairKey
+{
+    domain_id_t launch, capture;
+    ClockDomainPairKey(domain_id_t launch, domain_id_t capture) : launch(launch), capture(capture){};
+    inline bool operator==(const ClockDomainPairKey &other) const
+    {
+        return (launch == other.launch) && (capture == other.capture);
+    }
+    unsigned int hash() const { return mkhash(launch, capture); }
+};
+
+struct TimingAnalyser
+{
+  public:
+    TimingAnalyser(Context *ctx) : ctx(ctx){};
+    void setup();
+    void run(bool update_route_delays = true);
+    void print_report();
+
+    // This is used when routers etc are not actually binding detailed routing (due to congestion or an abstracted
+    // model), but want to re-run STA with their own calculated delays
+    void set_route_delay(CellPortKey port, DelayPair value);
+
+    float get_criticality(CellPortKey port) const { return ports.at(port).worst_crit; }
+    float get_setup_slack(CellPortKey port) const { return ports.at(port).worst_setup_slack; }
+    float get_domain_setup_slack(CellPortKey port) const
+    {
+        delay_t slack = std::numeric_limits<delay_t>::max();
+        for (const auto &dp : ports.at(port).domain_pairs)
+            slack = std::min(slack, domain_pairs.at(dp.first).worst_setup_slack);
+        return slack;
+    }
+
+    bool setup_only = false;
+    bool verbose_mode = false;
+    bool have_loops = false;
+    bool updated_domains = false;
+
+  private:
+    void init_ports();
+    void get_cell_delays();
+    void get_route_delays();
+    void topo_sort();
+    void setup_port_domains();
+
+    void reset_times();
+
+    void walk_forward();
+    void walk_backward();
+
+    void compute_slack();
+    void compute_criticality();
+
+    void print_fmax();
+    // get the N most failing endpoints for a given domain pair
+    std::vector<CellPortKey> get_failing_eps(domain_id_t domain_pair, int count);
+    // print the critical path for an endpoint and domain pair
+    void print_critical_path(CellPortKey endpoint, domain_id_t domain_pair);
+
+    const DelayPair init_delay{std::numeric_limits<delay_t>::max(), std::numeric_limits<delay_t>::lowest()};
+
+    // Set arrival/required times if more/less than the current value
+    void set_arrival_time(CellPortKey target, domain_id_t domain, DelayPair arrival, int path_length,
+                          CellPortKey prev = CellPortKey());
+    void set_required_time(CellPortKey target, domain_id_t domain, DelayPair required, int path_length,
+                           CellPortKey prev = CellPortKey());
+
+    // To avoid storing the domain tag structure (which could get large when considering more complex constrained tag
+    // cases), assign each domain an ID and use that instead
+    // An arrival or required time entry. Stores both the min/max delays; and the traversal to reach them for critical
+    // path reporting
+    struct ArrivReqTime
+    {
+        DelayPair value;
+        CellPortKey bwd_min, bwd_max;
+        int path_length;
+    };
+    // Data per port-domain tuple
+    struct PortDomainPairData
+    {
+        delay_t setup_slack = std::numeric_limits<delay_t>::max(), hold_slack = std::numeric_limits<delay_t>::max();
+        delay_t budget = std::numeric_limits<delay_t>::max();
+        int max_path_length = 0;
+        float criticality = 0;
+    };
+
+    // A cell timing arc, used to cache cell timings and reduce the number of potentially-expensive Arch API calls
+    struct CellArc
+    {
+
+        enum ArcType
+        {
+            COMBINATIONAL,
+            SETUP,
+            HOLD,
+            CLK_TO_Q
+        } type;
+
+        IdString other_port;
+        DelayQuad value;
+        // Clock polarity, not used for combinational arcs
+        ClockEdge edge;
+
+        CellArc(ArcType type, IdString other_port, DelayQuad value)
+                : type(type), other_port(other_port), value(value), edge(RISING_EDGE){};
+        CellArc(ArcType type, IdString other_port, DelayQuad value, ClockEdge edge)
+                : type(type), other_port(other_port), value(value), edge(edge){};
+    };
+
+    // Timing data for every cell port
+    struct PerPort
+    {
+        CellPortKey cell_port;
+        PortType type;
+        // per domain timings
+        dict<domain_id_t, ArrivReqTime> arrival;
+        dict<domain_id_t, ArrivReqTime> required;
+        dict<domain_id_t, PortDomainPairData> domain_pairs;
+        // cell timing arcs to (outputs)/from (inputs)  from this port
+        std::vector<CellArc> cell_arcs;
+        // routing delay into this port (input ports only)
+        DelayPair route_delay{0};
+        // worst criticality and slack across domain pairs
+        float worst_crit = 0;
+        delay_t worst_setup_slack = std::numeric_limits<delay_t>::max(),
+                worst_hold_slack = std::numeric_limits<delay_t>::max();
+    };
+
+    struct PerDomain
+    {
+        PerDomain(ClockDomainKey key) : key(key){};
+        ClockDomainKey key;
+        // these are pairs (signal port; clock port)
+        std::vector<std::pair<CellPortKey, IdString>> startpoints, endpoints;
+    };
+
+    struct PerDomainPair
+    {
+        PerDomainPair(ClockDomainPairKey key) : key(key){};
+        ClockDomainPairKey key;
+        DelayPair period{0};
+        delay_t worst_setup_slack, worst_hold_slack;
+    };
+
+    CellInfo *cell_info(const CellPortKey &key);
+    PortInfo &port_info(const CellPortKey &key);
+
+    domain_id_t domain_id(IdString cell, IdString clock_port, ClockEdge edge);
+    domain_id_t domain_id(const NetInfo *net, ClockEdge edge);
+    domain_id_t domain_pair_id(domain_id_t launch, domain_id_t capture);
+
+    void copy_domains(const CellPortKey &from, const CellPortKey &to, bool backwards);
+
+    dict<CellPortKey, PerPort> ports;
+    dict<ClockDomainKey, domain_id_t> domain_to_id;
+    dict<ClockDomainPairKey, domain_id_t> pair_to_id;
+    std::vector<PerDomain> domains;
+    std::vector<PerDomainPair> domain_pairs;
+
+    std::vector<CellPortKey> topological_order;
+
+    Context *ctx;
+};
+
+// Evenly redistribute the total path slack amongst all sinks on each path
+void assign_budget(Context *ctx, bool quiet = false);
+
+// Perform timing analysis and print out the fmax, and optionally the
+//    critical path
+void timing_analysis(Context *ctx, bool slack_histogram = true, bool print_fmax = true, bool print_path = false,
+                     bool warn_on_failure = false, bool update_results = false);
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/kernel/util.h b/common/kernel/util.h
new file mode 100644
index 00000000..c10abb72
--- /dev/null
+++ b/common/kernel/util.h
@@ -0,0 +1,241 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  gatecat <gatecat@ds0.me>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef UTIL_H
+#define UTIL_H
+
+#include <map>
+#include <set>
+#include <string>
+#include "nextpnr.h"
+
+#include "log.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+// Get a value from a map-style container, returning default if value is not
+// found
+template <typename Container, typename KeyType, typename ValueType>
+ValueType get_or_default(const Container &ct, const KeyType &key, ValueType def = ValueType())
+{
+    auto found = ct.find(key);
+    if (found == ct.end())
+        return def;
+    else
+        return found->second;
+};
+
+// Get a value from a map-style container, returning default if value is not
+// found (forces string)
+template <typename Container, typename KeyType>
+std::string str_or_default(const Container &ct, const KeyType &key, std::string def = "")
+{
+    auto found = ct.find(key);
+    if (found == ct.end())
+        return def;
+    else {
+        return found->second;
+    }
+};
+
+template <typename KeyType>
+std::string str_or_default(const dict<KeyType, Property> &ct, const KeyType &key, std::string def = "")
+{
+    auto found = ct.find(key);
+    if (found == ct.end())
+        return def;
+    else {
+        if (!found->second.is_string)
+            log_error("Expecting string value but got integer %d.\n", int(found->second.intval));
+        return found->second.as_string();
+    }
+};
+
+// Get a value from a map-style container, converting to int, and returning
+// default if value is not found
+template <typename Container, typename KeyType> int int_or_default(const Container &ct, const KeyType &key, int def = 0)
+{
+    auto found = ct.find(key);
+    if (found == ct.end())
+        return def;
+    else
+        return std::stoi(found->second);
+};
+
+template <typename KeyType> int int_or_default(const dict<KeyType, Property> &ct, const KeyType &key, int def = 0)
+{
+    auto found = ct.find(key);
+    if (found == ct.end())
+        return def;
+    else {
+        if (found->second.is_string) {
+            try {
+                return std::stoi(found->second.as_string());
+            } catch (std::invalid_argument &e) {
+                log_error("Expecting numeric value but got '%s'.\n", found->second.as_string().c_str());
+            }
+        } else
+            return found->second.as_int64();
+    }
+};
+
+// As above, but convert to bool
+template <typename Container, typename KeyType>
+bool bool_or_default(const Container &ct, const KeyType &key, bool def = false)
+{
+    return bool(int_or_default(ct, key, int(def)));
+};
+
+// Return a net if port exists, or nullptr
+inline const NetInfo *get_net_or_empty(const CellInfo *cell, const IdString port)
+{
+    auto found = cell->ports.find(port);
+    if (found != cell->ports.end())
+        return found->second.net;
+    else
+        return nullptr;
+}
+
+inline NetInfo *get_net_or_empty(CellInfo *cell, const IdString port)
+{
+    auto found = cell->ports.find(port);
+    if (found != cell->ports.end())
+        return found->second.net;
+    else
+        return nullptr;
+}
+
+// Get only value from a forward iterator begin/end pair.
+//
+// Generates assertion failure if std::distance(begin, end) != 1.
+template <typename ForwardIterator>
+inline const typename ForwardIterator::reference get_only_value(ForwardIterator begin, ForwardIterator end)
+{
+    NPNR_ASSERT(begin != end);
+    const typename ForwardIterator::reference ret = *begin;
+    ++begin;
+    NPNR_ASSERT(begin == end);
+    return ret;
+}
+
+// Get only value from a forward iterator range pair.
+//
+// Generates assertion failure if std::distance(r.begin(), r.end()) != 1.
+template <typename ForwardRange> inline auto get_only_value(ForwardRange r)
+{
+    auto b = r.begin();
+    auto e = r.end();
+    return get_only_value(b, e);
+}
+
+// From Yosys
+// https://github.com/YosysHQ/yosys/blob/0fb4224ebca86156a1296b9210116d9a9cbebeed/kernel/utils.h#L131
+template <typename T, typename C = std::less<T>> struct TopoSort
+{
+    bool analyze_loops, found_loops;
+    std::map<T, std::set<T, C>, C> database;
+    std::set<std::set<T, C>> loops;
+    std::vector<T> sorted;
+
+    TopoSort()
+    {
+        analyze_loops = true;
+        found_loops = false;
+    }
+
+    void node(T n)
+    {
+        if (database.count(n) == 0)
+            database[n] = std::set<T, C>();
+    }
+
+    void edge(T left, T right)
+    {
+        node(left);
+        database[right].insert(left);
+    }
+
+    void sort_worker(const T &n, std::set<T, C> &marked_cells, std::set<T, C> &active_cells,
+                     std::vector<T> &active_stack)
+    {
+        if (active_cells.count(n)) {
+            found_loops = true;
+            if (analyze_loops) {
+                std::set<T, C> loop;
+                for (int i = int(active_stack.size()) - 1; i >= 0; i--) {
+                    loop.insert(active_stack[i]);
+                    if (active_stack[i] == n)
+                        break;
+                }
+                loops.insert(loop);
+            }
+            return;
+        }
+
+        if (marked_cells.count(n))
+            return;
+
+        if (!database.at(n).empty()) {
+            if (analyze_loops)
+                active_stack.push_back(n);
+            active_cells.insert(n);
+
+            for (auto &left_n : database.at(n))
+                sort_worker(left_n, marked_cells, active_cells, active_stack);
+
+            if (analyze_loops)
+                active_stack.pop_back();
+            active_cells.erase(n);
+        }
+
+        marked_cells.insert(n);
+        sorted.push_back(n);
+    }
+
+    bool sort()
+    {
+        loops.clear();
+        sorted.clear();
+        found_loops = false;
+
+        std::set<T, C> marked_cells;
+        std::set<T, C> active_cells;
+        std::vector<T> active_stack;
+
+        for (auto &it : database)
+            sort_worker(it.first, marked_cells, active_cells, active_stack);
+
+        NPNR_ASSERT(sorted.size() == database.size());
+        return !found_loops;
+    }
+};
+
+template <typename T> struct reversed_range_t
+{
+    T &obj;
+    explicit reversed_range_t(T &obj) : obj(obj){};
+    auto begin() { return obj.rbegin(); }
+    auto end() { return obj.rend(); }
+};
+
+template <typename T> reversed_range_t<T> reversed_range(T &obj) { return reversed_range_t<T>(obj); }
+
+NEXTPNR_NAMESPACE_END
+
+#endif