From dc4ab55b27a2ada341b060bfe12dade99bf94daf Mon Sep 17 00:00:00 2001
From: David Shah <davey1576@gmail.com>
Date: Fri, 3 Aug 2018 16:59:45 +0200
Subject: [PATCH] Adding constraint satisfaction checks for debugging

Signed-off-by: David Shah <davey1576@gmail.com>
---
 common/nextpnr.h       |  2 +-
 common/place_common.cc |  6 +++++-
 common/placer1.cc      | 19 ++++++++++++-------
 3 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/common/nextpnr.h b/common/nextpnr.h
index f01173e6..f49b982e 100644
--- a/common/nextpnr.h
+++ b/common/nextpnr.h
@@ -281,7 +281,7 @@ struct CellInfo : ArchCellInfo
     std::unordered_map<IdString, IdString> pins;
 
     // placement constraints
-    CellInfo *constr_parent;
+    CellInfo *constr_parent = nullptr;
     std::vector<CellInfo *> constr_children;
     const int UNCONSTR = INT_MIN;
     int constr_x = UNCONSTR;   // this.x - parent.x
diff --git a/common/place_common.cc b/common/place_common.cc
index 8a30f592..11823360 100644
--- a/common/place_common.cc
+++ b/common/place_common.cc
@@ -438,13 +438,17 @@ class ConstraintLegaliseWorker
             }
         }
         for (auto rippedCell : rippedCells) {
-            bool res = place_single_cell(ctx, rippedCell, STRENGTH_WEAK);
+            bool res = place_single_cell(ctx, rippedCell, true);
             if (!res) {
                 log_error("failed to place cell '%s' after relative constraint legalisation\n",
                           rippedCell->name.c_str(ctx));
                 return false;
             }
         }
+        for (auto cell : sorted(ctx->cells))
+            if (get_constraints_distance(ctx, cell.second) != 0)
+                log_error("constraint satisfaction check failed for cell '%s' at Bel '%s'\n", cell.first.c_str(ctx),
+                          ctx->getBelName(cell.second->bel).c_str(ctx));
         return true;
     }
 };
diff --git a/common/placer1.cc b/common/placer1.cc
index 27206139..601a0245 100644
--- a/common/placer1.cc
+++ b/common/placer1.cc
@@ -40,11 +40,12 @@
 #include "place_common.h"
 #include "timing.h"
 #include "util.h"
+
 NEXTPNR_NAMESPACE_BEGIN
 
 class SAPlacer
 {
-  public:
+public:
     SAPlacer(Context *ctx) : ctx(ctx)
     {
         int num_bel_types = 0;
@@ -59,11 +60,11 @@ class SAPlacer
                 type_idx = bel_types.at(type);
             }
             if (int(fast_bels.size()) < type_idx + 1)
-                fast_bels.resize(type_idx + 1);
+            fast_bels.resize(type_idx + 1);
             if (int(fast_bels.at(type_idx).size()) < (loc.x + 1))
-                fast_bels.at(type_idx).resize(loc.x + 1);
+            fast_bels.at(type_idx).resize(loc.x + 1);
             if (int(fast_bels.at(type_idx).at(loc.x).size()) < (loc.y + 1))
-                fast_bels.at(type_idx).at(loc.x).resize(loc.y + 1);
+            fast_bels.at(type_idx).at(loc.x).resize(loc.y + 1);
             max_x = std::max(max_x, loc.x);
             max_y = std::max(max_y, loc.y);
             fast_bels.at(type_idx).at(loc.x).at(loc.y).push_back(bel);
@@ -272,12 +273,16 @@ class SAPlacer
                 }
             }
         }
+        for (auto cell : sorted(ctx->cells))
+            if (get_constraints_distance(ctx, cell.second) != 0)
+                log_error("constraint satisfaction check failed for cell '%s' at Bel '%s'\n", cell.first.c_str(ctx),
+                          ctx->getBelName(cell.second->bel).c_str(ctx));
         timing_analysis(ctx, true /* print_fmax */);
         ctx->unlock();
         return true;
     }
 
-  private:
+private:
     // Initial random placement
     void place_initial(CellInfo *cell)
     {
@@ -286,7 +291,7 @@ class SAPlacer
         while (!all_placed) {
             BelId best_bel = BelId();
             uint64_t best_score = std::numeric_limits<uint64_t>::max(),
-                     best_ripup_score = std::numeric_limits<uint64_t>::max();
+                    best_ripup_score = std::numeric_limits<uint64_t>::max();
             CellInfo *ripup_target = nullptr;
             BelId ripup_bel = BelId();
             if (cell->bel != BelId()) {
@@ -397,7 +402,7 @@ class SAPlacer
             metrics.at(new_wl.first) = new_wl.second;
 
         return true;
-    swap_fail:
+        swap_fail:
         ctx->bindBel(oldBel, cell->name, STRENGTH_WEAK);
         if (other != IdString()) {
             ctx->bindBel(newBel, other, STRENGTH_WEAK);