Add experimental support for tracing the state of the VM heap to a file

src/spaces-inl.h

 // 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 152 matching lines @@
                        MemoryChunk* chunk,
                        Executability executable,
                        PagedSpace* owner) {
   Page* page = reinterpret_cast<Page*>(chunk);
   ASSERT(chunk->size() == static_cast<size_t>(kPageSize));
   ASSERT(chunk->owner() == owner);
   owner->IncreaseCapacity(Page::kObjectAreaSize);
   owner->Free(page->ObjectAreaStart(),
               static_cast<int>(page->ObjectAreaEnd() -
                                page->ObjectAreaStart()));
+  for (HeapVisualizer* vis = heap->visualizer();
+       vis != NULL;
+       vis = vis->next()) {
+    vis->Name(v8::HeapVisualizer::kHeapOverheadPseudoSpaceIdentity,
+              reinterpret_cast<uintptr_t>(page->address()),
+              page->ObjectAreaStart() - page->address());
+    vis->ConstantAllocation(reinterpret_cast<uintptr_t>(page->address()),
+                            page->ObjectAreaStart() - page->address(),
+                            0);
+  }
 
   heap->incremental_marking()->SetOldSpacePageFlags(chunk);
 
   return page;
 }
 
 
 bool PagedSpace::Contains(Address addr) {
   Page* p = Page::FromAddress(addr);
   if (!p->is_valid()) return false;
   return p->owner() == this;
 }
 
 
+void PagedSpace::SetTop(Address top, Address limit) {
+  if (heap()->has_visualizer()) {
+    VisualizeTopChange(top);
+  }
+  ASSERT(top == limit ||
+         Page::FromAddress(top) == Page::FromAddress(limit - 1));
+  allocation_info_.top = top;
+  allocation_info_.limit = limit;
+}
+
+
 void MemoryChunk::set_scan_on_scavenge(bool scan) {
   if (scan) {
     if (!scan_on_scavenge()) heap_->increment_scan_on_scavenge_pages();
     SetFlag(SCAN_ON_SCAVENGE);
   } else {
     if (scan_on_scavenge()) heap_->decrement_scan_on_scavenge_pages();
     ClearFlag(SCAN_ON_SCAVENGE);
   }
   heap_->incremental_marking()->SetOldSpacePageFlags(this);
 }
@@ skipping 166 matching lines @@
   Map* map = object->map();
   Heap* heap = object->GetHeap();
   return map == heap->raw_unchecked_free_space_map()
       || map == heap->raw_unchecked_one_pointer_filler_map()
       || map == heap->raw_unchecked_two_pointer_filler_map();
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_INL_H_