Make heap iterable in PrepareForBreakPoints.

src/mark-compact.cc

 // Copyright 2011 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 240 matching lines @@
     heap()->old_data_space()->EvictEvacuationCandidatesFromFreeLists();
     heap()->code_space()->EvictEvacuationCandidatesFromFreeLists();
 
     compacting_ = evacuation_candidates_.length() > 0;
   }
 
   return compacting_;
 }
 
 
+void MarkCompactCollector::AbortCompaction() {
+  if (compacting_) {
+    int npages = evacuation_candidates_.length();
+    for (int i = 0; i < npages; i++) {
+      Page* p = evacuation_candidates_[i];
+      slots_buffer_allocator_.DeallocateChain(p->slots_buffer_address());
+      p->ClearEvacuationCandidate();
+      p->ClearFlag(MemoryChunk::RESCAN_ON_EVACUATION);
+    }
+    compacting_ = false;
+    evacuation_candidates_.Rewind(0);
+  }
+  ASSERT_EQ(0, evacuation_candidates_.length());
+}
+
+
 void MarkCompactCollector::CollectGarbage() {
   // Make sure that Prepare() has been called. The individual steps below will
   // update the state as they proceed.
   ASSERT(state_ == PREPARE_GC);
   ASSERT(encountered_weak_maps_ == Smi::FromInt(0));
 
   MarkLiveObjects();
   ASSERT(heap_->incremental_marking()->IsStopped());
 
   if (collect_maps_) ClearNonLiveTransitions();
@@ skipping 200 matching lines @@
   if (FLAG_gdbjit) {
     // If GDBJIT interface is active disable compaction.
     compacting_collection_ = false;
   }
 #endif
 
   // Clear marking bits for precise sweeping to collect all garbage.
   if (heap()->incremental_marking()->IsMarking() && PreciseSweepingRequired()) {
     heap()->incremental_marking()->Abort();
     ClearMarkbits(heap_);
+    AbortCompaction();
   }
 
   if (!FLAG_never_compact) StartCompaction();
 
   PagedSpaces spaces;
   for (PagedSpace* space = spaces.next();
        space != NULL;
        space = spaces.next()) {
     space->PrepareForMarkCompact();
   }
@@ skipping 3133 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal