17 files changed, 319 insertions, 357 deletions

diff --git a/common/command.cc b/common/command.cc
index 3eafdb17..dc98d032 100644
--- a/common/command.cc
+++ b/common/command.cc
@@ -28,6 +28,7 @@
 #endif
 
 #include <boost/algorithm/string/join.hpp>
+#include <boost/algorithm/string.hpp>
 #include <boost/filesystem/convenience.hpp>
 #include <boost/program_options.hpp>
 #include <fstream>
@@ -35,6 +36,7 @@
 #include "command.h"
 #include "design_utils.h"
 #include "jsonparse.h"
+#include "jsonwrite.h"
 #include "log.h"
 #include "timing.h"
 #include "util.h"
@@ -120,6 +122,7 @@ po::options_description CommandHandler::getGeneralOptions()
 
 #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()("seed", po::value<int>(), "seed value for random number generator");
     general.add_options()("randomize-seed,r", "randomize seed value for random number generator");
 
@@ -135,6 +138,9 @@ po::options_description CommandHandler::getGeneralOptions()
     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");
 
@@ -143,13 +149,14 @@ po::options_description CommandHandler::getGeneralOptions()
     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()("save", po::value<std::string>(), "project file to write");
-    general.add_options()("load", po::value<std::string>(), "project file to read");
     return general;
 }
 
 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;
     }
@@ -177,9 +184,9 @@ void CommandHandler::setupContext(Context *ctx)
     }
 
     if (vm.count("slack_redist_iter")) {
-        ctx->slack_redist_iter = vm["slack_redist_iter"].as<int>();
+        ctx->settings[ctx->id("slack_redist_iter")] = vm["slack_redist_iter"].as<std::string>();
         if (vm.count("freq") && vm["freq"].as<double>() == 0) {
-            ctx->auto_freq = true;
+            ctx->settings[ctx->id("auto_freq")] = std::to_string(true);
 #ifndef NO_GUI
             if (!vm.count("gui"))
 #endif
@@ -188,11 +195,11 @@ void CommandHandler::setupContext(Context *ctx)
     }
 
     if (vm.count("ignore-loops")) {
-        settings->set("timing/ignoreLoops", true);
+        ctx->settings[ctx->id("timing/ignoreLoops")] = std::to_string(true);
     }
 
     if (vm.count("timing-allow-fail")) {
-        settings->set("timing/allowFail", true);
+        ctx->settings[ctx->id("timing/allowFail")] = std::to_string(true);
     }
 
     if (vm.count("placer")) {
@@ -201,30 +208,43 @@ void CommandHandler::setupContext(Context *ctx)
             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());
-        settings->set("placer", placer);
-    } else {
-        settings->set("placer", Arch::defaultPlacer);
+        ctx->settings[ctx->id("placer")] = placer;
     }
 
     if (vm.count("cstrweight")) {
-        settings->set("placer1/constraintWeight", vm["cstrweight"].as<float>());
+        ctx->settings[ctx->id("placer1/constraintWeight")] = std::to_string(vm["cstrweight"].as<float>());
     }
     if (vm.count("starttemp")) {
-        settings->set("placer1/startTemp", vm["starttemp"].as<float>());
+        ctx->settings[ctx->id("placer1/startTemp")] = std::to_string(vm["starttemp"].as<float>());
     }
 
     if (vm.count("placer-budgets")) {
-        settings->set("placer1/budgetBased", true);
+        ctx->settings[ctx->id("placer1/budgetBased")] = std::to_string(true);
     }
     if (vm.count("freq")) {
         auto freq = vm["freq"].as<double>();
         if (freq > 0)
-            ctx->target_freq = freq * 1e6;
+            ctx->settings[ctx->id("target_freq")] = std::to_string(freq * 1e6);
     }
 
-    ctx->timing_driven = true;
     if (vm.count("no-tmdriv"))
-        ctx->timing_driven = false;
+        ctx->settings[ctx->id("timing_driven")] = std::to_string(false);
+
+    // 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")] = std::to_string(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")] = std::to_string(false);
+    if (ctx->settings.find(ctx->id("placer")) == ctx->settings.end())    
+        ctx->settings[ctx->id("placer")] = Arch::defaultPlacer;
+
+    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")] = std::to_string(ctx->rngstate);
 }
 
 int CommandHandler::executeMain(std::unique_ptr<Context> ctx)
@@ -237,19 +257,17 @@ int CommandHandler::executeMain(std::unique_ptr<Context> ctx)
 #ifndef NO_GUI
     if (vm.count("gui")) {
         Application a(argc, argv, (vm.count("gui-no-aa") > 0));
-        MainWindow w(std::move(ctx), chipArgs);
+        MainWindow w(std::move(ctx), this);
         try {
             if (vm.count("json")) {
                 std::string filename = vm["json"].as<std::string>();
                 std::ifstream f(filename);
-                w.notifyChangeContext();
                 if (!parse_json_file(f, filename, w.getContext()))
                     log_error("Loading design failed.\n");
 
                 customAfterLoad(w.getContext());
-                w.updateLoaded();
-            } else if (vm.count("load")) {
-                w.projectLoad(vm["load"].as<std::string>());
+                w.notifyChangeContext();
+                w.updateActions();
             } else
                 w.notifyChangeContext();
         } catch (log_execution_error_exception) {
@@ -280,31 +298,42 @@ int CommandHandler::executeMain(std::unique_ptr<Context> ctx)
             execute_python_file(filename.c_str());
     } else
 #endif
-            if (vm.count("json") || vm.count("load")) {
-        run_script_hook("pre-pack");
-        if (!ctx->pack() && !ctx->force)
-            log_error("Packing design failed.\n");
+    if (vm.count("json")) {
+        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());
-        run_script_hook("pre-place");
 
-        if (!vm.count("pack-only")) {
+        if (do_place) {
+            run_script_hook("pre-place");
             if (!ctx->place() && !ctx->force)
                 log_error("Placing design failed.\n");
             ctx->check();
-            run_script_hook("pre-route");
+        }
 
+        if (do_route) {
+            run_script_hook("pre-route");
             if (!ctx->route() && !ctx->force)
                 log_error("Routing design failed.\n");
+            run_script_hook("post-route");
         }
-        run_script_hook("post-route");
 
         customBitstream(ctx.get());
     }
 
-    if (vm.count("save")) {
-        project.save(ctx.get(), vm["save"].as<std::string>());
+    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");
     }
 
 #ifndef NO_PYTHON
@@ -341,13 +370,14 @@ int CommandHandler::exec()
         if (executeBeforeContext())
             return 0;
 
-        std::unique_ptr<Context> ctx;
-        if (vm.count("load") && vm.count("gui") == 0) {
-            ctx = project.load(vm["load"].as<std::string>());
-        } else {
-            ctx = createContext();
+        std::unordered_map<std::string,Property> values;
+        if (vm.count("json")) {
+            std::string filename = vm["json"].as<std::string>();
+            std::ifstream f(filename);
+            if (!load_json_settings(f, filename, values))
+                log_error("Loading design failed.\n");
         }
-        settings = std::unique_ptr<Settings>(new Settings(ctx.get()));
+        std::unique_ptr<Context> ctx = createContext(values);
         setupContext(ctx.get());
         setupArchContext(ctx.get());
         int rc = executeMain(std::move(ctx));
@@ -359,6 +389,27 @@ int CommandHandler::exec()
     }
 }
 
+std::unique_ptr<Context> CommandHandler::load_json(std::string filename)
+{
+    vm.clear();
+    std::unordered_map<std::string,Property> values;
+    {
+        std::ifstream f(filename);
+        if (!load_json_settings(f, filename, values))
+            log_error("Loading design failed.\n");
+    }
+    std::unique_ptr<Context> ctx = createContext(values);
+    setupContext(ctx.get());
+    setupArchContext(ctx.get());
+    {
+        std::ifstream f(filename);
+        if (!parse_json_file(f, filename, ctx.get()))
+            log_error("Loading design failed.\n");
+    }
+    customAfterLoad(ctx.get());
+    return ctx;
+}
+
 void CommandHandler::run_script_hook(const std::string &name)
 {
 #ifndef NO_PYTHON
diff --git a/common/command.h b/common/command.h
index d0f1d328..b5908e3f 100644
--- a/common/command.h
+++ b/common/command.h
@@ -22,9 +22,9 @@
 #define COMMAND_H
 
 #include <boost/program_options.hpp>
+#include <fstream>
 #include "nextpnr.h"
-#include "project.h"
-#include "settings.h"
+#include "log.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
@@ -37,10 +37,11 @@ class CommandHandler
     virtual ~CommandHandler(){};
 
     int exec();
+    std::unique_ptr<Context> load_json(std::string filename);
 
   protected:
     virtual void setupArchContext(Context *ctx) = 0;
-    virtual std::unique_ptr<Context> createContext() = 0;
+    virtual std::unique_ptr<Context> createContext(std::unordered_map<std::string,Property> &values) = 0;
     virtual po::options_description getArchOptions() = 0;
     virtual void validate(){};
     virtual void customAfterLoad(Context *ctx){};
@@ -58,15 +59,12 @@ class CommandHandler
 
   protected:
     po::variables_map vm;
-    ArchArgs chipArgs;
-    std::unique_ptr<Settings> settings;
 
   private:
     po::options_description options;
     po::positional_options_description pos;
     int argc;
     char **argv;
-    ProjectHandler project;
     std::ofstream logfile;
 };
 
diff --git a/common/nextpnr.cc b/common/nextpnr.cc
index daaadf28..a026b60d 100644
--- a/common/nextpnr.cc
+++ b/common/nextpnr.cc
@@ -19,6 +19,7 @@
 
 #include "nextpnr.h"
 #include "log.h"
+#include <boost/algorithm/string.hpp>
 
 NEXTPNR_NAMESPACE_BEGIN
 
@@ -453,4 +454,119 @@ DecalXY BaseCtx::constructDecalXY(DecalId decal, float x, float 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).c_str(this);
+            ci->attrs[id("BEL_STRENGTH")] = std::to_string((int)ci->belStrength);
+        }
+        if (ci->constr_x!= ci->UNCONSTR)
+            ci->attrs[id("CONSTR_X")] = std::to_string(ci->constr_x);
+        if (ci->constr_y!= ci->UNCONSTR)
+            ci->attrs[id("CONSTR_Y")] = std::to_string(ci->constr_y);
+        if (ci->constr_z!= ci->UNCONSTR) {
+            ci->attrs[id("CONSTR_Z")] = std::to_string(ci->constr_z);
+            ci->attrs[id("CONSTR_ABS_Z")] = std::to_string(ci->constr_abs_z ? 1 : 0);
+        }
+        if (ci->constr_parent!= nullptr)
+            ci->attrs[id("CONSTR_PARENT")] = ci->constr_parent->name.c_str(this);
+        if (!ci->constr_children.empty()) {
+            std::string constr = "";
+            for(auto &item : ci->constr_children)
+            {
+                if (!constr.empty()) constr += std::string(";");
+                constr += item->name.c_str(this);
+            }            
+            ci->attrs[id("CONSTR_CHILDREN")] = constr;
+        }
+    }
+    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).c_str(this);
+            routing += ";";
+            if (item.second.pip != PipId())
+                routing += getCtx()->getPipName(item.second.pip).c_str(this);
+            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)std::stoi(str->second.str);
+            
+            BelId b = getCtx()->getBelByName(id(val->second.str));
+            getCtx()->bindBel(b, ci, strength);
+        }
+        val = ci->attrs.find(id("CONSTR_X"));
+        if (val != ci->attrs.end())
+            ci->constr_x = std::stoi(val->second.str);
+
+        val = ci->attrs.find(id("CONSTR_Y"));
+        if (val != ci->attrs.end())
+            ci->constr_y = std::stoi(val->second.str);
+
+        val = ci->attrs.find(id("CONSTR_Z"));
+        if (val != ci->attrs.end()) 
+            ci->constr_z = std::stoi(val->second.str);
+
+        val = ci->attrs.find(id("CONSTR_ABS_Z"));
+        if (val != ci->attrs.end())
+            ci->constr_abs_z = std::stoi(val->second.str)==1;
+
+        val = ci->attrs.find(id("CONSTR_PARENT"));
+        if (val != ci->attrs.end()) {
+            auto parent = cells.find(id(val->second.str));
+            if (parent != cells.end())
+                ci->constr_parent = parent->second.get();
+        }
+        val = ci->attrs.find(id("CONSTR_CHILDREN"));
+        if (val != ci->attrs.end()) {
+            std::vector<std::string> strs;
+            boost::split(strs,val->second.str,boost::is_any_of(";"));
+            for(auto val : strs)
+            {
+                ci->constr_children.push_back(cells.find(id(val.c_str()))->second.get());
+            }            
+        }
+    }
+    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;
+            boost::split(strs,val->second.str,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(id(wire)), ni, strength);
+                else
+                    getCtx()->bindPip(getCtx()->getPipByName(id(pip)), ni, strength);
+            }
+        }
+    }
+    getCtx()->assignArchInfo();
+}
+
 NEXTPNR_NAMESPACE_END
diff --git a/common/nextpnr.h b/common/nextpnr.h
index fc49300e..6950ac76 100644
--- a/common/nextpnr.h
+++ b/common/nextpnr.h
@@ -32,6 +32,7 @@
 #include <vector>
 
 #include <boost/functional/hash.hpp>
+#include <boost/lexical_cast.hpp>
 
 #ifndef NEXTPNR_H
 #define NEXTPNR_H
@@ -286,6 +287,41 @@ struct PipMap
     PlaceStrength strength = STRENGTH_NONE;
 };
 
+struct Property
+{
+    bool is_string;
+    
+    std::string str;
+    int num;
+
+    std::string::iterator begin() { return str.begin(); }
+    std::string::iterator end() { return str.end(); }
+
+    bool isString() const { return is_string; }
+
+    void setNumber(int val) { is_string = false; num = val; str =  std::to_string(val); }
+    void setString(std::string val) { is_string = true; str = val; }
+
+    const char * c_str() const { return str.c_str(); }
+    operator std::string () const { return str; }
+
+    bool operator==(const std::string other) const
+    {
+        return str == other;
+    }    
+    bool operator!=(const std::string other) const
+    {
+        return str != other;
+    }    
+
+    Property& operator=(std::string other)
+    {
+        is_string = true;
+        str = other;
+        return *this;
+    }
+};
+
 struct ClockConstraint;
 
 struct NetInfo : ArchNetInfo
@@ -295,7 +331,7 @@ struct NetInfo : ArchNetInfo
 
     PortRef driver;
     std::vector<PortRef> users;
-    std::unordered_map<IdString, std::string> attrs;
+    std::unordered_map<IdString, Property> attrs;
 
     // wire -> uphill_pip
     std::unordered_map<WireId, PipMap> wires;
@@ -328,7 +364,7 @@ struct CellInfo : ArchCellInfo
     int32_t udata;
 
     std::unordered_map<IdString, PortInfo> ports;
-    std::unordered_map<IdString, std::string> attrs, params;
+    std::unordered_map<IdString, Property> attrs, params;
 
     BelId bel;
     PlaceStrength belStrength = STRENGTH_NONE;
@@ -506,15 +542,21 @@ struct BaseCtx
     mutable std::vector<const std::string *> *idstring_idx_to_str;
 
     // Project settings and config switches
-    std::unordered_map<IdString, std::string> settings;
+    std::unordered_map<IdString, Property> settings;
 
     // Placed nets and cells.
     std::unordered_map<IdString, std::unique_ptr<NetInfo>> nets;
     std::unordered_map<IdString, std::unique_ptr<CellInfo>> cells;
 
+    // Top-level ports
+    std::unordered_map<IdString, PortInfo> ports;
+
     // Floorplanning regions
     std::unordered_map<IdString, std::unique_ptr<Region>> region;
 
+    // Context meta data
+    std::unordered_map<IdString, Property> attrs;
+
     BaseCtx()
     {
         idstring_str_to_idx = new std::unordered_map<std::string, int>;
@@ -646,6 +688,9 @@ struct BaseCtx
 
     // Workaround for lack of wrappable constructors
     DecalXY constructDecalXY(DecalId decal, float x, float y);
+
+    void archInfoToAttributes();
+    void attributesToArchInfo();
 };
 
 NEXTPNR_NAMESPACE_END
@@ -659,10 +704,6 @@ struct Context : Arch, DeterministicRNG
     bool verbose = false;
     bool debug = false;
     bool force = false;
-    bool timing_driven = true;
-    float target_freq = 12e6;
-    bool auto_freq = false;
-    int slack_redist_iter = 0;
 
     Context(ArchArgs args) : Arch(args) {}
 
@@ -683,6 +724,26 @@ struct Context : Arch, DeterministicRNG
 
     void check() const;
     void archcheck() const;
+
+    template <typename T> T setting(const char *name, T defaultValue)
+    {
+        IdString new_id = id(name);
+        if (settings.find(new_id) != settings.end())
+            return boost::lexical_cast<T>(settings.find(new_id)->second.str);
+        else
+            settings[id(name)] = std::to_string(defaultValue);
+ 
+        return defaultValue;        
+    }
+    
+    template <typename T> T setting(const char *name) const
+    {
+        IdString new_id = id(name);
+        if (settings.find(new_id) != settings.end())
+            return boost::lexical_cast<T>(settings.find(new_id)->second.str);
+        else
+            throw std::runtime_error("settings does not exists");
+    }
 };
 
 NEXTPNR_NAMESPACE_END
diff --git a/common/place_common.cc b/common/place_common.cc
index 73a320d0..cb9799b5 100644
--- a/common/place_common.cc
+++ b/common/place_common.cc
@@ -37,7 +37,7 @@ wirelen_t get_net_metric(const Context *ctx, const NetInfo *net, MetricType type
     if (driver_gb)
         return 0;
     int clock_count;
-    bool timing_driven = ctx->timing_driven && type == MetricType::COST &&
+    bool timing_driven = ctx->setting<bool>("timing_driven") && type == MetricType::COST &&
                          ctx->getPortTimingClass(driver_cell, net->driver.port, clock_count) != TMG_IGNORE;
     delay_t negative_slack = 0;
     delay_t worst_slack = std::numeric_limits<delay_t>::max();
diff --git a/common/placer1.cc b/common/placer1.cc
index a8ddd8a6..a2272b83 100644
--- a/common/placer1.cc
+++ b/common/placer1.cc
@@ -219,7 +219,7 @@ class SAPlacer
             if ((placed_cells - constr_placed_cells) % 500 != 0)
                 log_info("  initial placement placed %d/%d cells\n", int(placed_cells - constr_placed_cells),
                          int(autoplaced.size()));
-            if (cfg.budgetBased && ctx->slack_redist_iter > 0)
+            if (cfg.budgetBased && ctx->setting<int>("slack_redist_iter") > 0)
                 assign_budget(ctx);
             ctx->yield();
             auto iplace_end = std::chrono::high_resolution_clock::now();
@@ -370,16 +370,16 @@ class SAPlacer
                     ctx->shuffle(autoplaced);
 
                     // Legalisation is a big change so force a slack redistribution here
-                    if (ctx->slack_redist_iter > 0 && cfg.budgetBased)
+                    if (ctx->setting<int>("slack_redist_iter") > 0 && cfg.budgetBased)
                         assign_budget(ctx, true /* quiet */);
                 }
                 require_legal = false;
-            } else if (cfg.budgetBased && ctx->slack_redist_iter > 0 && iter % ctx->slack_redist_iter == 0) {
+            } else if (cfg.budgetBased && ctx->setting<int>("slack_redist_iter") > 0 && iter % ctx->setting<int>("slack_redist_iter") == 0) {
                 assign_budget(ctx, true /* quiet */);
             }
 
             // Invoke timing analysis to obtain criticalities
-            if (!cfg.budgetBased && ctx->timing_driven)
+            if (!cfg.budgetBased && ctx->setting<bool>("timing_driven"))
                 get_criticalities(ctx, &net_crit);
             // Need to rebuild costs after criticalities change
             setup_costs();
@@ -804,7 +804,7 @@ class SAPlacer
             if (ignore_net(ni))
                 continue;
             net_bounds[ni->udata] = get_net_bounds(ni);
-            if (ctx->timing_driven && int(ni->users.size()) < cfg.timingFanoutThresh)
+            if (ctx->setting<bool>("timing_driven") && int(ni->users.size()) < cfg.timingFanoutThresh)
                 for (size_t i = 0; i < ni->users.size(); i++)
                     net_arc_tcost[ni->udata][i] = get_timing_cost(ni, i);
         }
@@ -1021,7 +1021,7 @@ class SAPlacer
                 }
             }
 
-            if (ctx->timing_driven && int(pn->users.size()) < cfg.timingFanoutThresh) {
+            if (ctx->setting<bool>("timing_driven") && int(pn->users.size()) < cfg.timingFanoutThresh) {
                 // Output ports - all arcs change timing
                 if (port.second.type == PORT_OUT) {
                     int cc;
@@ -1061,7 +1061,7 @@ class SAPlacer
             if (md.already_bounds_changed_x[bc] == MoveChangeData::NO_CHANGE)
                 md.wirelen_delta += md.new_net_bounds[bc].hpwl() - net_bounds[bc].hpwl();
 
-        if (ctx->timing_driven) {
+        if (ctx->setting<bool>("timing_driven")) {
             for (const auto &tc : md.changed_arcs) {
                 double old_cost = net_arc_tcost.at(tc.first).at(tc.second);
                 double new_cost = get_timing_cost(net_by_udata.at(tc.first), tc.second);
@@ -1131,12 +1131,12 @@ class SAPlacer
     Placer1Cfg cfg;
 };
 
-Placer1Cfg::Placer1Cfg(Context *ctx) : Settings(ctx)
+Placer1Cfg::Placer1Cfg(Context *ctx)
 {
-    constraintWeight = get<float>("placer1/constraintWeight", 10);
-    minBelsForGridPick = get<int>("placer1/minBelsForGridPick", 64);
-    budgetBased = get<bool>("placer1/budgetBased", false);
-    startTemp = get<float>("placer1/startTemp", 1);
+    constraintWeight = ctx->setting<float>("placer1/constraintWeight", 10);
+    minBelsForGridPick = ctx->setting<int>("placer1/minBelsForGridPick", 64);
+    budgetBased = ctx->setting<bool>("placer1/budgetBased", false);
+    startTemp = ctx->setting<float>("placer1/startTemp", 1);
     timingFanoutThresh = std::numeric_limits<int>::max();
 }
 
diff --git a/common/placer1.h b/common/placer1.h
index 4c7c7339..0f2e2894 100644
--- a/common/placer1.h
+++ b/common/placer1.h
@@ -20,11 +20,11 @@
 #define PLACE_H
 
 #include "nextpnr.h"
-#include "settings.h"
+#include "log.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
-struct Placer1Cfg : public Settings
+struct Placer1Cfg
 {
     Placer1Cfg(Context *ctx);
     float constraintWeight;
diff --git a/common/placer_heap.cc b/common/placer_heap.cc
index f9b639f8..7b72200a 100644
--- a/common/placer_heap.cc
+++ b/common/placer_heap.cc
@@ -234,7 +234,7 @@ class HeAPPlacer
                          std::chrono::duration<double>(run_stopt - run_startt).count());
             }
 
-            if (ctx->timing_driven)
+            if (ctx->setting<bool>("timing_driven"))
                 get_criticalities(ctx, &net_crit);
 
             if (legal_hpwl < best_hpwl) {
@@ -1516,11 +1516,11 @@ int HeAPPlacer::CutSpreader::seq = 0;
 
 bool placer_heap(Context *ctx, PlacerHeapCfg cfg) { return HeAPPlacer(ctx, cfg).place(); }
 
-PlacerHeapCfg::PlacerHeapCfg(Context *ctx) : Settings(ctx)
+PlacerHeapCfg::PlacerHeapCfg(Context *ctx)
 {
-    alpha = get<float>("placerHeap/alpha", 0.1);
-    criticalityExponent = get<int>("placerHeap/criticalityExponent", 2);
-    timingWeight = get<int>("placerHeap/timingWeight", 10);
+    alpha = ctx->setting<float>("placerHeap/alpha", 0.1);
+    criticalityExponent = ctx->setting<int>("placerHeap/criticalityExponent", 2);
+    timingWeight = ctx->setting<int>("placerHeap/timingWeight", 10);
 }
 
 NEXTPNR_NAMESPACE_END
@@ -1538,7 +1538,7 @@ bool placer_heap(Context *ctx, PlacerHeapCfg cfg)
     return false;
 }
 
-PlacerHeapCfg::PlacerHeapCfg(Context *ctx) : Settings(ctx) {}
+PlacerHeapCfg::PlacerHeapCfg(Context *ctx) {}
 
 NEXTPNR_NAMESPACE_END
 
diff --git a/common/placer_heap.h b/common/placer_heap.h
index 841aa0d9..2def5e75 100644
--- a/common/placer_heap.h
+++ b/common/placer_heap.h
@@ -27,11 +27,11 @@
 #ifndef PLACER_HEAP_H
 #define PLACER_HEAP_H
 #include "nextpnr.h"
-#include "settings.h"
+#include "log.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
-struct PlacerHeapCfg : public Settings
+struct PlacerHeapCfg
 {
     PlacerHeapCfg(Context *ctx);
 
diff --git a/common/project.cc b/common/project.cc
deleted file mode 100644
index b0ebe961..00000000
--- a/common/project.cc
+++ /dev/null
@@ -1,144 +0,0 @@
-/*
- *  nextpnr -- Next Generation Place and Route
- *
- *  Copyright (C) 2018  Miodrag Milanovic <miodrag@symbioticeda.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 "project.h"
-#include <algorithm>
-#include <boost/filesystem/convenience.hpp>
-#include <boost/property_tree/json_parser.hpp>
-#include <fstream>
-#include "jsonparse.h"
-#include "log.h"
-
-NEXTPNR_NAMESPACE_BEGIN
-
-boost::filesystem::path make_relative(boost::filesystem::path child, boost::filesystem::path parent)
-{
-    boost::filesystem::path::const_iterator parentIter = parent.begin();
-    boost::filesystem::path::const_iterator childIter = child.begin();
-
-    while (parentIter != parent.end() && childIter != child.end() && (*childIter) == (*parentIter)) {
-        ++childIter;
-        ++parentIter;
-    }
-
-    boost::filesystem::path finalPath;
-    while (parentIter != parent.end()) {
-        finalPath /= "..";
-        ++parentIter;
-    }
-
-    while (childIter != child.end()) {
-        finalPath /= *childIter;
-        ++childIter;
-    }
-
-    return finalPath;
-}
-
-void ProjectHandler::save(Context *ctx, std::string filename)
-{
-    try {
-        boost::filesystem::path proj(filename);
-        std::ofstream f(filename);
-        pt::ptree root;
-
-        log_info("Saving project %s...\n", filename.c_str());
-        log_break();
-
-        root.put("project.version", 1);
-        root.put("project.name", boost::filesystem::basename(filename));
-        root.put("project.arch.name", ctx->archId().c_str(ctx));
-        root.put("project.arch.type", ctx->archArgsToId(ctx->archArgs()).c_str(ctx));
-        std::string fn = ctx->settings[ctx->id("input/json")];
-        root.put("project.input.json", make_relative(fn, proj.parent_path()).string());
-        root.put("project.params.freq", int(ctx->target_freq / 1e6));
-        root.put("project.params.seed", ctx->rngstate);
-        saveArch(ctx, root, proj.parent_path().string());
-        for (auto const &item : ctx->settings) {
-            std::string path = "project.settings.";
-            path += item.first.c_str(ctx);
-            std::replace(path.begin(), path.end(), '/', '.');
-            root.put(path, item.second);
-        }
-        pt::write_json(f, root);
-    } catch (...) {
-        log_error("Error saving project file.\n");
-    }
-}
-
-void addSettings(Context *ctx, std::string path, pt::ptree sub)
-{
-    for (pt::ptree::value_type &v : sub) {
-        const std::string &key = v.first;
-        const boost::property_tree::ptree &subtree = v.second;
-        if (subtree.empty()) {
-            ctx->settings.emplace(ctx->id(path + key), subtree.get_value<std::string>().c_str());
-        } else {
-            addSettings(ctx, path + key + "/", subtree);
-        }
-    }
-}
-
-std::unique_ptr<Context> ProjectHandler::load(std::string filename)
-{
-    std::unique_ptr<Context> ctx;
-    try {
-        pt::ptree root;
-        boost::filesystem::path proj(filename);
-        pt::read_json(filename, root);
-        log_info("Loading project %s...\n", filename.c_str());
-        log_break();
-
-        int version = root.get<int>("project.version");
-        if (version != 1)
-            log_error("Wrong project format version.\n");
-
-        ctx = createContext(root);
-
-        std::string arch_name = root.get<std::string>("project.arch.name");
-        if (arch_name != ctx->archId().c_str(ctx.get()))
-            log_error("Unsuported project architecture.\n");
-
-        auto project = root.get_child("project");
-        auto input = project.get_child("input");
-        std::string fn = input.get<std::string>("json");
-        boost::filesystem::path json = proj.parent_path() / fn;
-        std::ifstream f(json.string());
-        if (!parse_json_file(f, fn, ctx.get()))
-            log_error("Loading design failed.\n");
-
-        if (project.count("params")) {
-            auto params = project.get_child("params");
-            if (params.count("freq"))
-                ctx->target_freq = params.get<double>("freq") * 1e6;
-            if (params.count("seed"))
-                ctx->rngseed(params.get<uint64_t>("seed"));
-        }
-        if (project.count("settings")) {
-            addSettings(ctx.get(), "", project.get_child("settings"));
-        }
-
-        loadArch(ctx.get(), root, proj.parent_path().string());
-    } catch (...) {
-        log_error("Error loading project file.\n");
-    }
-    return ctx;
-}
-
-NEXTPNR_NAMESPACE_END
diff --git a/common/project.h b/common/project.h
deleted file mode 100644
index 03b4b7b5..00000000
--- a/common/project.h
+++ /dev/null
@@ -1,45 +0,0 @@
-/*
- *  nextpnr -- Next Generation Place and Route
- *
- *  Copyright (C) 2018  Miodrag Milanovic <miodrag@symbioticeda.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 PROJECT_H
-#define PROJECT_H
-
-#include <boost/filesystem/convenience.hpp>
-#include <boost/property_tree/ptree.hpp>
-#include "nextpnr.h"
-
-NEXTPNR_NAMESPACE_BEGIN
-
-namespace pt = boost::property_tree;
-
-struct ProjectHandler
-{
-    void save(Context *ctx, std::string filename);
-    std::unique_ptr<Context> load(std::string filename);
-    // implemented per arch
-    void saveArch(Context *ctx, pt::ptree &root, std::string path);
-    std::unique_ptr<Context> createContext(pt::ptree &root);
-    void loadArch(Context *ctx, pt::ptree &root, std::string path);
-};
-
-boost::filesystem::path make_relative(boost::filesystem::path child, boost::filesystem::path parent);
-
-NEXTPNR_NAMESPACE_END
-
-#endif // PROJECT_H
diff --git a/common/pybindings.cc b/common/pybindings.cc
index 60f87e27..52dd9717 100644
--- a/common/pybindings.cc
+++ b/common/pybindings.cc
@@ -122,7 +122,7 @@ BOOST_PYTHON_MODULE(MODULE_NAME)
             .value("PORT_INOUT", PORT_INOUT)
             .export_values();
 
-    typedef std::unordered_map<IdString, std::string> AttrMap;
+    typedef std::unordered_map<IdString, Property> AttrMap;
     typedef std::unordered_map<IdString, PortInfo> PortMap;
     typedef std::unordered_map<IdString, IdString> PinMap;
     typedef std::unordered_map<IdString, std::unique_ptr<Region>> RegionMap;
diff --git a/common/router1.cc b/common/router1.cc
index 28a422c8..02c817c7 100644
--- a/common/router1.cc
+++ b/common/router1.cc
@@ -733,12 +733,12 @@ struct Router1
 
 NEXTPNR_NAMESPACE_BEGIN
 
-Router1Cfg::Router1Cfg(Context *ctx) : Settings(ctx)
+Router1Cfg::Router1Cfg(Context *ctx)
 {
-    maxIterCnt = get<int>("router1/maxIterCnt", 200);
-    cleanupReroute = get<bool>("router1/cleanupReroute", true);
-    fullCleanupReroute = get<bool>("router1/fullCleanupReroute", true);
-    useEstimate = get<bool>("router1/useEstimate", true);
+    maxIterCnt = ctx->setting<int>("router1/maxIterCnt", 200);
+    cleanupReroute = ctx->setting<bool>("router1/cleanupReroute", true);
+    fullCleanupReroute = ctx->setting<bool>("router1/fullCleanupReroute", true);
+    useEstimate = ctx->setting<bool>("router1/useEstimate", true);
 
     wireRipupPenalty = ctx->getRipupDelayPenalty();
     netRipupPenalty = 10 * ctx->getRipupDelayPenalty();
diff --git a/common/router1.h b/common/router1.h
index 80d7aa96..f3d325ad 100644
--- a/common/router1.h
+++ b/common/router1.h
@@ -21,11 +21,10 @@
 #define ROUTER1_H
 
 #include "nextpnr.h"
-#include "settings.h"
-
+#include "log.h"
 NEXTPNR_NAMESPACE_BEGIN
 
-struct Router1Cfg : Settings
+struct Router1Cfg
 {
     Router1Cfg(Context *ctx);
 
diff --git a/common/settings.h b/common/settings.h
deleted file mode 100644
index b57947c9..00000000
--- a/common/settings.h
+++ /dev/null
@@ -1,74 +0,0 @@
-/*
- *  nextpnr -- Next Generation Place and Route
- *
- *  Copyright (C) 2018  Miodrag Milanovic <miodrag@symbioticeda.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 SETTINGS_H
-#define SETTINGS_H
-
-#include <boost/lexical_cast.hpp>
-#include "log.h"
-#include "nextpnr.h"
-
-NEXTPNR_NAMESPACE_BEGIN
-
-class Settings
-{
-  public:
-    explicit Settings(Context *ctx) : ctx(ctx) {}
-
-    template <typename T> T get(const char *name, T defaultValue)
-    {
-        try {
-            IdString id = ctx->id(name);
-            auto pair = ctx->settings.emplace(id, std::to_string(defaultValue));
-            if (!pair.second) {
-                return boost::lexical_cast<T>(pair.first->second);
-            }
-
-        } catch (boost::bad_lexical_cast &) {
-            log_error("Problem reading setting %s, using default value\n", name);
-        }
-        return defaultValue;
-    }
-
-    template <typename T> void set(const char *name, T value);
-
-  private:
-    Context *ctx;
-};
-
-template <typename T> inline void Settings::set(const char *name, T value)
-{
-    IdString id = ctx->id(name);
-    auto pair = ctx->settings.emplace(id, std::to_string(value));
-    if (!pair.second) {
-        ctx->settings[pair.first->first] = value;
-    }
-}
-
-template <> inline void Settings::set<std::string>(const char *name, std::string value)
-{
-    IdString id = ctx->id(name);
-    auto pair = ctx->settings.emplace(id, value);
-    if (!pair.second) {
-        ctx->settings[pair.first->first] = value;
-    }
-}
-
-NEXTPNR_NAMESPACE_END
-
-#endif // SETTINGS_H
diff --git a/common/timing.cc b/common/timing.cc
index e67ac231..60aef3fa 100644
--- a/common/timing.cc
+++ b/common/timing.cc
@@ -113,7 +113,7 @@ struct Timing
 
     Timing(Context *ctx, bool net_delays, bool update, CriticalPathMap *crit_path = nullptr,
            DelayFrequency *slack_histogram = nullptr, NetCriticalityMap *net_crit = nullptr)
-            : ctx(ctx), net_delays(net_delays), update(update), min_slack(1.0e12 / ctx->target_freq),
+            : 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), net_crit(net_crit),
               async_clock(ctx->id("$async$"))
     {
@@ -121,7 +121,7 @@ struct Timing
 
     delay_t walk_paths()
     {
-        const auto clk_period = ctx->getDelayFromNS(1.0e9 / ctx->target_freq).maxDelay();
+        const auto clk_period = ctx->getDelayFromNS(1.0e9 / ctx->setting<float>("target_freq")).maxDelay();
 
         // First, compute the topographical 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
@@ -658,17 +658,17 @@ 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->target_freq / 1e6);
+        log_info("Annotating ports with timing budgets for target frequency %.2f MHz\n", ctx->setting<float>("target_freq") / 1e6);
     }
 
-    Timing timing(ctx, ctx->slack_redist_iter > 0 /* net_delays */, true /* update */);
+    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->auto_freq && user.budget < 0)
+                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),
@@ -684,13 +684,13 @@ void assign_budget(Context *ctx, bool quiet)
 
     // For slack redistribution, if user has not specified a frequency dynamically adjust the target frequency to be the
     // currently achieved maximum
-    if (ctx->auto_freq && ctx->slack_redist_iter > 0) {
-        delay_t default_slack = delay_t((1.0e9 / ctx->getDelayNS(1)) / ctx->target_freq);
-        ctx->target_freq = 1.0e9 / ctx->getDelayNS(default_slack - timing.min_slack);
+    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->target_freq / 1e6);
+                     ctx->getDelayNS(timing.min_slack),ctx->setting<float>("target_freq") / 1e6);
     }
 
     if (!quiet)
@@ -897,7 +897,7 @@ void timing_analysis(Context *ctx, bool print_histogram, bool print_fmax, bool p
         for (auto &clock : clock_reports) {
             const auto &clock_name = clock.first.str(ctx);
             const int width = max_width - clock_name.size();
-            float target = ctx->target_freq / 1e6;
+            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());
 
diff --git a/common/timing_opt.h b/common/timing_opt.h
index ceb35c71..cdc02406 100644
--- a/common/timing_opt.h
+++ b/common/timing_opt.h
@@ -18,13 +18,13 @@
  */
 
 #include "nextpnr.h"
-#include "settings.h"
+#include "log.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
-struct TimingOptCfg : public Settings
+struct TimingOptCfg
 {
-    TimingOptCfg(Context *ctx) : Settings(ctx) {}
+    TimingOptCfg(Context *ctx) {}
 
     // The timing optimiser will *only* optimise cells of these types
     // Normally these would only be logic cells (or tiles if applicable), the algorithm makes little sense