Refactor common placement functions out of SA placer for use in legaliser

Signed-off-by: David Shah <davey1576@gmail.com>

4 files changed, 138 insertions, 58 deletions

diff --git a/common/nextpnr.h b/common/nextpnr.h
index efe5936f..8d4714bf 100644
--- a/common/nextpnr.h
+++ b/common/nextpnr.h
@@ -200,7 +200,7 @@ struct BaseCtx
 
     BaseCtx()
     {
-        //assert(IdString::global_ctx == nullptr);
+        // assert(IdString::global_ctx == nullptr);
         IdString::global_ctx = this;
 
         idstring_str_to_idx = new std::unordered_map<std::string, int>;
@@ -229,6 +229,7 @@ struct Context : Arch
     bool verbose = false;
     bool debug = false;
     bool force = false;
+    bool timing_driven = true;
 
     Context(ArchArgs args) : Arch(args) {}
 
diff --git a/common/place_common.cc b/common/place_common.cc
new file mode 100644
index 00000000..86060cd8
--- /dev/null
+++ b/common/place_common.cc
@@ -0,0 +1,92 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  David Shah <david@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 "place_common.h"
+#include <cmath>
+#include "log.h"
+#include "util.h"
+NEXTPNR_NAMESPACE_BEGIN
+
+// Get the total estimated wirelength for a net
+wirelen_t get_net_wirelength(const Context *ctx, const NetInfo *net, float &tns)
+{
+    wirelen_t wirelength = 0;
+    int driver_x, driver_y;
+    bool driver_gb;
+    CellInfo *driver_cell = net->driver.cell;
+    if (!driver_cell)
+        return 0;
+    if (driver_cell->bel == BelId())
+        return 0;
+    ctx->estimatePosition(driver_cell->bel, driver_x, driver_y, driver_gb);
+    WireId drv_wire = ctx->getWireBelPin(driver_cell->bel, ctx->portPinFromId(net->driver.port));
+    if (driver_gb)
+        return 0;
+    float worst_slack = 1000;
+    int xmin = driver_x, xmax = driver_x, ymin = driver_y, ymax = driver_y;
+    for (auto load : net->users) {
+        if (load.cell == nullptr)
+            continue;
+        CellInfo *load_cell = load.cell;
+        if (load_cell->bel == BelId())
+            continue;
+        if (ctx->timing_driven) {
+            WireId user_wire = ctx->getWireBelPin(load_cell->bel, ctx->portPinFromId(load.port));
+            delay_t raw_wl = ctx->estimateDelay(drv_wire, user_wire);
+            float slack = ctx->getDelayNS(load.budget) - ctx->getDelayNS(raw_wl);
+            if (slack < 0)
+                tns += slack;
+            worst_slack = std::min(slack, worst_slack);
+        }
+
+        int load_x, load_y;
+        bool load_gb;
+        ctx->estimatePosition(load_cell->bel, load_x, load_y, load_gb);
+        if (load_gb)
+            continue;
+        xmin = std::min(xmin, load_x);
+        ymin = std::min(ymin, load_y);
+        xmax = std::max(xmax, load_x);
+        ymax = std::max(ymax, load_y);
+    }
+    if (ctx->timing_driven) {
+        wirelength = wirelen_t((((ymax - ymin) + (xmax - xmin)) * std::min(5.0, (1.0 + std::exp(-worst_slack / 5)))));
+    } else {
+        wirelength = wirelen_t((ymax - ymin) + (xmax - xmin));
+    }
+
+    return wirelength;
+}
+
+// Get the total wirelength for a cell
+wirelen_t get_cell_wirelength(const Context *ctx, const CellInfo *cell)
+{
+    std::set<IdString> nets;
+    for (auto p : cell->ports) {
+        nets.insert(p.first);
+    }
+    wirelen_t wirelength = 0;
+    float tns = 0;
+    for (auto n : nets) {
+        wirelength += get_net_wirelength(ctx, ctx->nets.at(n).get(), tns);
+    }
+    return wirelength;
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/place_common.h b/common/place_common.h
new file mode 100644
index 00000000..b81574b9
--- /dev/null
+++ b/common/place_common.h
@@ -0,0 +1,40 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  David Shah <david@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 PLACE_COMMON_H
+#define PLACE_COMMON_H
+
+#include "nextpnr.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+typedef int64_t wirelen_t;
+
+// Return the wirelength of a net
+wirelen_t get_net_wirelength(const Context *ctx, const NetInfo *net, float &tns);
+
+// Return the wirelength of all nets connected to a cell
+wirelen_t get_cell_wirelength(const Context *ctx, const CellInfo *cell);
+
+// Place a single cell in the lowest wirelength Bel available, optionally requiring validity check
+bool place_single_cell(const Context *ctx, CellInfo *cell, bool require_legality);
+
+NEXTPNR_NAMESPACE_END
+
+#endif
diff --git a/common/place_sa.cc b/common/place_sa.cc
index 3e900c84..ed584d60 100644
--- a/common/place_sa.cc
+++ b/common/place_sa.cc
@@ -37,11 +37,10 @@
 #include <string.h>
 #include <vector>
 #include "log.h"
+#include "place_common.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
-typedef int64_t wirelen_t;
-
 class SAPlacer
 {
   public:
@@ -138,7 +137,7 @@ class SAPlacer
         curr_wirelength = 0;
         curr_tns = 0;
         for (auto &net : ctx->nets) {
-            wirelen_t wl = get_wirelength(net.second.get(), curr_tns);
+            wirelen_t wl = get_net_wirelength(ctx, net.second.get(), curr_tns);
             wirelengths[net.first] = wl;
             curr_wirelength += wl;
         }
@@ -212,7 +211,7 @@ class SAPlacer
             curr_wirelength = 0;
             curr_tns = 0;
             for (auto &net : ctx->nets) {
-                wirelen_t wl = get_wirelength(net.second.get(), curr_tns);
+                wirelen_t wl = get_net_wirelength(ctx, net.second.get(), curr_tns);
                 wirelengths[net.first] = wl;
                 curr_wirelength += wl;
             }
@@ -289,58 +288,6 @@ class SAPlacer
         }
     }
 
-    // Get the total estimated wirelength for a net
-    wirelen_t get_wirelength(NetInfo *net, float &tns)
-    {
-        wirelen_t wirelength = 0;
-        int driver_x, driver_y;
-        bool driver_gb;
-        CellInfo *driver_cell = net->driver.cell;
-        if (!driver_cell)
-            return 0;
-        if (driver_cell->bel == BelId())
-            return 0;
-        ctx->estimatePosition(driver_cell->bel, driver_x, driver_y, driver_gb);
-        WireId drv_wire = ctx->getWireBelPin(driver_cell->bel, ctx->portPinFromId(net->driver.port));
-        if (driver_gb)
-            return 0;
-        float worst_slack = 1000;
-        int xmin = driver_x, xmax = driver_x, ymin = driver_y, ymax = driver_y;
-        for (auto load : net->users) {
-            if (load.cell == nullptr)
-                continue;
-            CellInfo *load_cell = load.cell;
-            if (load_cell->bel == BelId())
-                continue;
-            if (timing_driven) {
-                WireId user_wire = ctx->getWireBelPin(load_cell->bel, ctx->portPinFromId(load.port));
-                delay_t raw_wl = ctx->estimateDelay(drv_wire, user_wire);
-                float slack = ctx->getDelayNS(load.budget) - ctx->getDelayNS(raw_wl);
-                if (slack < 0)
-                    tns += slack;
-                worst_slack = std::min(slack, worst_slack);
-            }
-
-            int load_x, load_y;
-            bool load_gb;
-            ctx->estimatePosition(load_cell->bel, load_x, load_y, load_gb);
-            if (load_gb)
-                continue;
-            xmin = std::min(xmin, load_x);
-            ymin = std::min(ymin, load_y);
-            xmax = std::max(xmax, load_x);
-            ymax = std::max(ymax, load_y);
-        }
-        if (timing_driven) {
-            wirelength =
-                    wirelen_t((((ymax - ymin) + (xmax - xmin)) * std::min(5.0, (1.0 + std::exp(-worst_slack / 5)))));
-        } else {
-            wirelength = wirelen_t((ymax - ymin) + (xmax - xmin));
-        }
-
-        return wirelength;
-    }
-
     // Attempt a SA position swap, return true on success or false on failure
     bool try_swap_position(CellInfo *cell, BelId newBel)
     {
@@ -387,7 +334,7 @@ class SAPlacer
         for (auto net : update) {
             new_wirelength -= wirelengths.at(net->name);
             float temp_tns = 0;
-            wirelen_t net_new_wl = get_wirelength(net, temp_tns);
+            wirelen_t net_new_wl = get_net_wirelength(ctx, net, temp_tns);
             new_wirelength += net_new_wl;
             new_lengths.push_back(std::make_pair(net->name, net_new_wl));
         }