--verify-predictable mode added for ensuring that GC behaves deterministically.

src/heap-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_INL_H_
 #define V8_HEAP_INL_H_
 
 #include <cmath>
 
 #include "src/heap.h"
@@ skipping 217 matching lines @@
     allocation = map_space_->AllocateRaw(size_in_bytes);
   }
   if (allocation.IsRetry()) old_gen_exhausted_ = true;
   if (profiler->is_tracking_allocations() && allocation.To(&object)) {
     profiler->AllocationEvent(object->address(), size_in_bytes);
   }
   return allocation;
 }
 
 
+void Heap::OnAllocationEvent(HeapObject* object, int size_in_bytes) {
+  ++allocations_count_;
+
+  Address object_address = object->address();
+  MemoryChunk* memory_chunk = MemoryChunk::FromAddress(object_address);
+  uint32_t offset =
+      static_cast<uint32_t>(object_address - memory_chunk->address());
+
+  UpdateAllocationsHash(offset);
+  UpdateAllocationsHash(size_in_bytes);
+  UpdateAllocationsHash(memory_chunk->owner()->identity());
+
+  if (FLAG_dump_allocations_digest_at_alloc > 0) {
+    if (--dump_allocations_hash_countdown_ == 0) {
+      dump_allocations_hash_countdown_ = FLAG_dump_allocations_digest_at_alloc;
+      PrintAlloctionsHash();
+    }
+  }
+}
+
+
+void Heap::UpdateAllocationsHash(uint32_t value) {
+  uint16_t c1 = static_cast<uint16_t>(value);
+  uint16_t c2 = static_cast<uint16_t>(value >> 16);
+  raw_allocations_hash_ =
+      StringHasher::AddCharacterCore(raw_allocations_hash_, c1);
+  raw_allocations_hash_ =
+      StringHasher::AddCharacterCore(raw_allocations_hash_, c2);
+}
+
+
+void Heap::PrintAlloctionsHash() {
+  uint32_t hash = StringHasher::GetHashCore(raw_allocations_hash_);
+  PrintF("\n### Allocations = %u, hash = 0x%08x\n", allocations_count_, hash);
+}
+
+
 void Heap::FinalizeExternalString(String* string) {
   ASSERT(string->IsExternalString());
   v8::String::ExternalStringResourceBase** resource_addr =
       reinterpret_cast<v8::String::ExternalStringResourceBase**>(
           reinterpret_cast<byte*>(string) +
           ExternalString::kResourceOffset -
           kHeapObjectTag);
 
   // Dispose of the C++ object if it has not already been disposed.
   if (*resource_addr != NULL) {
@@ skipping 477 matching lines @@
 
 
 double GCTracer::SizeOfHeapObjects() {
   return (static_cast<double>(heap_->SizeOfObjects())) / MB;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_INL_H_