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

src/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 67 matching lines @@
     for (Object** current = start; current < end; current++) {
       if ((*current)->IsHeapObject()) {
         HeapObject* object = HeapObject::cast(*current);
         CHECK(HEAP->mark_compact_collector()->IsMarked(object));
       }
     }
   }
 
   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()) {
       VisitPointer(rinfo->target_object_address());
     }
   }
 };
 
 
 static void VerifyMarking(Address bottom, Address top) {
@@ skipping 306 matching lines @@
   SweepSpaces();
 
   if (!FLAG_collect_maps) ReattachInitialMaps();
 
 #ifdef DEBUG
   if (FLAG_verify_native_context_separation) {
     VerifyNativeContextSeparation(heap_);
   }
 #endif
 
+#ifdef VERIFY_HEAP
+  if (FLAG_collect_maps && FLAG_weak_embedded_maps_in_optimized_code &&
+      heap()->weak_embedded_maps_verification_enabled()) {
+    VerifyWeakEmbeddedMapsInOptimizedCode();
+  }
+#endif
+
   Finish();
 
   if (marking_parity_ == EVEN_MARKING_PARITY) {
     marking_parity_ = ODD_MARKING_PARITY;
   } else {
     ASSERT(marking_parity_ == ODD_MARKING_PARITY);
     marking_parity_ = EVEN_MARKING_PARITY;
   }
 
   tracer_ = NULL;
@@ skipping 31 matching lines @@
   VerifyMarkbitsAreClean(heap_->map_space());
   VerifyMarkbitsAreClean(heap_->new_space());
 
   LargeObjectIterator it(heap_->lo_space());
   for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
     MarkBit mark_bit = Marking::MarkBitFrom(obj);
     CHECK(Marking::IsWhite(mark_bit));
     CHECK_EQ(0, Page::FromAddress(obj->address())->LiveBytes());
   }
 }
+
+
+void MarkCompactCollector::VerifyWeakEmbeddedMapsInOptimizedCode() {
+  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->VerifyEmbeddedMapsDependency();
+  }
+}
 #endif  // VERIFY_HEAP
 
 
 static void ClearMarkbitsInPagedSpace(PagedSpace* space) {
   PageIterator it(space);
 
   while (it.has_next()) {
     Bitmap::Clear(it.next());
   }
 }
@@ skipping 350 matching lines @@
     space->PrepareForMarkCompact();
   }
 
 #ifdef VERIFY_HEAP
   if (!was_marked_incrementally_ && FLAG_verify_heap) {
     VerifyMarkbitsAreClean();
   }
 #endif
 }
 
+
 class DeoptimizeMarkedCodeFilter : public OptimizedFunctionFilter {
  public:
   virtual bool TakeFunction(JSFunction* function) {
     return function->code()->marked_for_deoptimization();
   }
 };
 
 
 void MarkCompactCollector::Finish() {
 #ifdef DEBUG
@@ skipping 1457 matching lines @@
   AssertNoAllocation no_allocation_scope;
   DependentCodes* codes = map->dependent_codes();
   int number_of_codes = codes->number_of_codes();
   if (number_of_codes == 0) return;
   int new_number_of_codes = 0;
   for (int i = 0; i < number_of_codes; i++) {
     Code* code = codes->code_at(i);
     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);
+      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);
 }
 
 
 void MarkCompactCollector::ProcessWeakMaps() {
@@ skipping 1584 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal