Fix clearing of dead dependent codes and verify weak embedded maps on full GC.

src/mark-compact.cc

Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index bfb4031f3e42831d0c381efa05f542f2117c56e9..c018f9930bbfd6dde0c17ff7d3bf2e2d5aedeec5 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -85,7 +85,7 @@ class VerifyMarkingVisitor: public ObjectVisitor {
 
   void VisitEmbeddedPointer(RelocInfo* rinfo) {
     ASSERT(rinfo->rmode() == RelocInfo::EMBEDDED_OBJECT);
-    if (!FLAG_weak_embedded_maps_in_optimized_code ||
+    if (!FLAG_weak_embedded_maps_in_optimized_code || !FLAG_collect_maps ||
         rinfo->host()->kind() != Code::OPTIMIZED_FUNCTION ||
         !rinfo->target_object()->IsMap() ||
         !Map::cast(rinfo->target_object())->CanTransition()) {
@@ -833,6 +833,20 @@ void MarkCompactCollector::Prepare(GCTracer* tracer) {
 #endif
 }
 
+#ifdef VERIFY_HEAP
+static void VerifyWeakEmbeddedMapsInOptimizedCode(Heap* heap) {

[Michael Starzinger, 2013/01/31 14:27:50]

Move this function up to the other verifiers at the top of the file.

[ulan, 2013/02/04 09:54:06]

Done.

+  HeapObjectIterator code_iterator(heap->code_space());
+  for (HeapObject* obj = code_iterator.Next();
+       obj != NULL;
+       obj = code_iterator.Next()) {
+    Code* code = Code::cast(obj);
+    if (code->kind() != Code::OPTIMIZED_FUNCTION) continue;
+    if (code->marked_for_deoptimization()) continue;
+    code->VerifyEmbeddedMaps();
+  }
+}
+#endif
+
 class DeoptimizeMarkedCodeFilter : public OptimizedFunctionFilter {
  public:
   virtual bool TakeFunction(JSFunction* function) {
@@ -852,6 +866,13 @@ void MarkCompactCollector::Finish() {
   // objects (empty string, illegal builtin).
   heap()->isolate()->stub_cache()->Clear();
 
+#ifdef VERIFY_HEAP
+  if (FLAG_collect_maps && FLAG_weak_embedded_maps_in_optimized_code &&

[Michael Starzinger, 2013/01/31 14:27:50]

Move this call into MarkCompactCollector::CollectGarbage() where the other
verifiers are called.

[ulan, 2013/02/04 09:54:06]

Done.

+      heap()->weak_embedded_maps_verification_enabled()) {
+    VerifyWeakEmbeddedMapsInOptimizedCode(heap());
+  }
+#endif
+
   DeoptimizeMarkedCodeFilter filter;
   Deoptimizer::DeoptimizeAllFunctionsWith(&filter);
 }
@@ -2310,16 +2331,17 @@ void MarkCompactCollector::ClearNonLiveDependentCodes(Map* map) {
     if (IsMarked(code) && !code->marked_for_deoptimization()) {
       if (new_number_of_codes != i) {
         codes->set_code_at(new_number_of_codes, code);
-        Object** slot = codes->code_slot_at(new_number_of_codes);
-        RecordSlot(slot, slot, code);
-        new_number_of_codes++;
       }
+      Object** slot = codes->code_slot_at(new_number_of_codes);

[ulan, 2013/01/29 15:02:58]

This was the bug that lead to crashes.

[Michael Starzinger, 2013/01/31 14:27:50]

Ouch, nice catch, I should have seen that in my initial review.

+      RecordSlot(slot, slot, code);
+      new_number_of_codes++;
     }
   }
   for (int i = new_number_of_codes; i < number_of_codes; i++) {
     codes->clear_code_at(i);
   }
   codes->set_number_of_codes(new_number_of_codes);
+  number_of_codes = codes->number_of_codes();

[Michael Starzinger, 2013/01/31 14:27:50]

This call seems to be obsolete.

[ulan, 2013/02/04 09:54:06]

Done.

 }