Version 2.5.2

src/heap.cc

 // Copyright 2010 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 38 matching lines @@
 
 
 namespace v8 {
 namespace internal {
 
 
 String* Heap::hidden_symbol_;
 Object* Heap::roots_[Heap::kRootListLength];
 Object* Heap::global_contexts_list_;
 
+
 NewSpace Heap::new_space_;
 OldSpace* Heap::old_pointer_space_ = NULL;
 OldSpace* Heap::old_data_space_ = NULL;
 OldSpace* Heap::code_space_ = NULL;
 MapSpace* Heap::map_space_ = NULL;
 CellSpace* Heap::cell_space_ = NULL;
 LargeObjectSpace* Heap::lo_space_ = NULL;
 
+static const intptr_t kMinimumPromotionLimit = 2 * MB;
+static const intptr_t kMinimumAllocationLimit = 8 * MB;
+
 intptr_t Heap::old_gen_promotion_limit_ = kMinimumPromotionLimit;
 intptr_t Heap::old_gen_allocation_limit_ = kMinimumAllocationLimit;
 
 int Heap::old_gen_exhausted_ = false;
 
 int Heap::amount_of_external_allocated_memory_ = 0;
 int Heap::amount_of_external_allocated_memory_at_last_global_gc_ = 0;
 
 // semispace_size_ should be a power of 2 and old_generation_size_ should be
 // a multiple of Page::kPageSize.
@@ skipping 331 matching lines @@
   Counters::number_of_symbols.Set(symbol_table()->NumberOfElements());
 #if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
   ReportStatisticsAfterGC();
 #endif
 #ifdef ENABLE_DEBUGGER_SUPPORT
   Debug::AfterGarbageCollection();
 #endif
 }
 
 
-void Heap::CollectAllGarbage(bool force_compaction,
-                             CollectionPolicy collectionPolicy) {
+void Heap::CollectAllGarbage(bool force_compaction) {
   // Since we are ignoring the return value, the exact choice of space does
   // not matter, so long as we do not specify NEW_SPACE, which would not
   // cause a full GC.
   MarkCompactCollector::SetForceCompaction(force_compaction);
-  CollectGarbage(OLD_POINTER_SPACE, collectionPolicy);
+  CollectGarbage(OLD_POINTER_SPACE);
   MarkCompactCollector::SetForceCompaction(false);
 }
 
 
-void Heap::CollectAllAvailableGarbage() {
-  CompilationCache::Clear();
-  CollectAllGarbage(true, AGGRESSIVE);
-}
-
-
-void Heap::CollectGarbage(AllocationSpace space,
-                          CollectionPolicy collectionPolicy) {
+void Heap::CollectGarbage(AllocationSpace space) {
   // The VM is in the GC state until exiting this function.
   VMState state(GC);
 
 #ifdef DEBUG
   // Reset the allocation timeout to the GC interval, but make sure to
   // allow at least a few allocations after a collection. The reason
   // for this is that we have a lot of allocation sequences and we
   // assume that a garbage collection will allow the subsequent
   // allocation attempts to go through.
   allocation_timeout_ = Max(6, FLAG_gc_interval);
 #endif
 
   { GCTracer tracer;
     GarbageCollectionPrologue();
     // The GC count was incremented in the prologue.  Tell the tracer about
     // it.
     tracer.set_gc_count(gc_count_);
 
     GarbageCollector collector = SelectGarbageCollector(space);
     // Tell the tracer which collector we've selected.
     tracer.set_collector(collector);
 
     HistogramTimer* rate = (collector == SCAVENGER)
         ? &Counters::gc_scavenger
         : &Counters::gc_compactor;
     rate->Start();
-    PerformGarbageCollection(collector, &tracer, collectionPolicy);
+    PerformGarbageCollection(collector, &tracer);
     rate->Stop();
 
     GarbageCollectionEpilogue();
   }
 
 
 #ifdef ENABLE_LOGGING_AND_PROFILING
   if (FLAG_log_gc) HeapProfiler::WriteSample();
   if (CpuProfiler::is_profiling()) CpuProfiler::ProcessMovedFunctions();
 #endif
 }
 
 
 void Heap::PerformScavenge() {
   GCTracer tracer;
-  PerformGarbageCollection(SCAVENGER, &tracer, NORMAL);
+  PerformGarbageCollection(SCAVENGER, &tracer);
 }
 
 
 #ifdef DEBUG
 // Helper class for verifying the symbol table.
 class SymbolTableVerifier : public ObjectVisitor {
  public:
   SymbolTableVerifier() { }
   void VisitPointers(Object** start, Object** end) {
     // Visit all HeapObject pointers in [start, end).
@@ skipping 164 matching lines @@
   } else if (survival_rate_diff < -kYoungSurvivalRateAllowedDeviation) {
     set_survival_rate_trend(INCREASING);
   } else {
     set_survival_rate_trend(STABLE);
   }
 
   survival_rate_ = survival_rate;
 }
 
 void Heap::PerformGarbageCollection(GarbageCollector collector,
-                                    GCTracer* tracer,
-                                    CollectionPolicy collectionPolicy) {
+                                    GCTracer* tracer) {
   if (collector != SCAVENGER) {
     PROFILE(CodeMovingGCEvent());
   }
 
   VerifySymbolTable();
   if (collector == MARK_COMPACTOR && global_gc_prologue_callback_) {
     ASSERT(!allocation_allowed_);
     GCTracer::Scope scope(tracer, GCTracer::Scope::EXTERNAL);
     global_gc_prologue_callback_();
   }
@@ skipping 13 matching lines @@
 
   if (collector == MARK_COMPACTOR) {
     // Perform mark-sweep with optional compaction.
     MarkCompact(tracer);
 
     bool high_survival_rate_during_scavenges = IsHighSurvivalRate() &&
         IsStableOrIncreasingSurvivalTrend();
 
     UpdateSurvivalRateTrend(start_new_space_size);
 
-    UpdateOldSpaceLimits();
+    intptr_t old_gen_size = PromotedSpaceSize();
+    old_gen_promotion_limit_ =
+        old_gen_size + Max(kMinimumPromotionLimit, old_gen_size / 3);
+    old_gen_allocation_limit_ =
+        old_gen_size + Max(kMinimumAllocationLimit, old_gen_size / 2);
 
-    // Major GC would invoke weak handle callbacks on weakly reachable
-    // handles, but won't collect weakly reachable objects until next
-    // major GC.  Therefore if we collect aggressively and weak handle callback
-    // has been invoked, we rerun major GC to release objects which become
-    // garbage.
-    if (collectionPolicy == AGGRESSIVE) {
-      // Note: as weak callbacks can execute arbitrary code, we cannot
-      // hope that eventually there will be no weak callbacks invocations.
-      // Therefore stop recollecting after several attempts.
-      const int kMaxNumberOfAttempts = 7;
-      for (int attempt = 0; attempt < kMaxNumberOfAttempts; attempt++) {
-        { DisableAssertNoAllocation allow_allocation;
-          GCTracer::Scope scope(tracer, GCTracer::Scope::EXTERNAL);
-          if (!GlobalHandles::PostGarbageCollectionProcessing()) break;
-        }
-        MarkCompact(tracer);
-        // Weak handle callbacks can allocate data, so keep limits correct.
-        UpdateOldSpaceLimits();
-      }
-    } else {
-      if (high_survival_rate_during_scavenges &&
-          IsStableOrIncreasingSurvivalTrend()) {
-        // Stable high survival rates of young objects both during partial and
-        // full collection indicate that mutator is either building or modifying
-        // a structure with a long lifetime.
-        // In this case we aggressively raise old generation memory limits to
-        // postpone subsequent mark-sweep collection and thus trade memory
-        // space for the mutation speed.
-        old_gen_promotion_limit_ *= 2;
-        old_gen_allocation_limit_ *= 2;
-      }
+    if (high_survival_rate_during_scavenges &&
+        IsStableOrIncreasingSurvivalTrend()) {
+      // Stable high survival rates of young objects both during partial and
+      // full collection indicate that mutator is either building or modifying
+      // a structure with a long lifetime.
+      // In this case we aggressively raise old generation memory limits to
+      // postpone subsequent mark-sweep collection and thus trade memory
+      // space for the mutation speed.
+      old_gen_promotion_limit_ *= 2;
+      old_gen_allocation_limit_ *= 2;
     }
 
-    { DisableAssertNoAllocation allow_allocation;
-      GCTracer::Scope scope(tracer, GCTracer::Scope::EXTERNAL);
-      GlobalHandles::PostGarbageCollectionProcessing();
-    }
+    old_gen_exhausted_ = false;
   } else {
     tracer_ = tracer;
     Scavenge();
     tracer_ = NULL;
 
     UpdateSurvivalRateTrend(start_new_space_size);
   }
 
   Counters::objs_since_last_young.Set(0);
 
+  if (collector == MARK_COMPACTOR) {
+    DisableAssertNoAllocation allow_allocation;
+    GCTracer::Scope scope(tracer, GCTracer::Scope::EXTERNAL);
+    GlobalHandles::PostGarbageCollectionProcessing();
+  }
+
   // Update relocatables.
   Relocatable::PostGarbageCollectionProcessing();
 
   if (collector == MARK_COMPACTOR) {
     // Register the amount of external allocated memory.
     amount_of_external_allocated_memory_at_last_global_gc_ =
         amount_of_external_allocated_memory_;
   }
 
   GCCallbackFlags callback_flags = tracer->is_compacting()
@@ skipping 56 matching lines @@
 
   CompletelyClearInstanceofCache();
 
   if (is_compacting) FlushNumberStringCache();
 
   ClearNormalizedMapCaches();
 }
 
 
 Object* Heap::FindCodeObject(Address a) {
-  Object* obj = code_space_->FindObject(a);
-  if (obj->IsFailure()) {
-    obj = lo_space_->FindObject(a);
+  Object* obj = NULL;  // Initialization to please compiler.
+  { MaybeObject* maybe_obj = code_space_->FindObject(a);
+    if (!maybe_obj->ToObject(&obj)) {
+      obj = lo_space_->FindObject(a)->ToObjectUnchecked();
+    }
   }
-  ASSERT(!obj->IsFailure());
   return obj;
 }
 
 
 // Helper class for copying HeapObjects
 class ScavengeVisitor: public ObjectVisitor {
  public:
 
   void VisitPointer(Object** p) { ScavengePointer(p); }
 
@@ skipping 433 matching lines @@
   template<ObjectContents object_contents, SizeRestriction size_restriction>
   static inline void EvacuateObject(Map* map,
                                     HeapObject** slot,
                                     HeapObject* object,
                                     int object_size) {
     ASSERT((size_restriction != SMALL) ||
            (object_size <= Page::kMaxHeapObjectSize));
     ASSERT(object->Size() == object_size);
 
     if (Heap::ShouldBePromoted(object->address(), object_size)) {
-      Object* result;
+      MaybeObject* maybe_result;
 
       if ((size_restriction != SMALL) &&
           (object_size > Page::kMaxHeapObjectSize)) {
-        result = Heap::lo_space()->AllocateRawFixedArray(object_size);
+        maybe_result = Heap::lo_space()->AllocateRawFixedArray(object_size);
       } else {
         if (object_contents == DATA_OBJECT) {
-          result = Heap::old_data_space()->AllocateRaw(object_size);
+          maybe_result = Heap::old_data_space()->AllocateRaw(object_size);
         } else {
-          result = Heap::old_pointer_space()->AllocateRaw(object_size);
+          maybe_result = Heap::old_pointer_space()->AllocateRaw(object_size);
         }
       }
 
-      if (!result->IsFailure()) {
+      Object* result = NULL;  // Initialization to please compiler.
+      if (maybe_result->ToObject(&result)) {
         HeapObject* target = HeapObject::cast(result);
         *slot = MigrateObject(object, target, object_size);
 
         if (object_contents == POINTER_OBJECT) {
           promotion_queue.insert(target, object_size);
         }
 
         Heap::tracer()->increment_promoted_objects_size(object_size);
         return;
       }
     }
-    Object* result = Heap::new_space()->AllocateRaw(object_size);
-    ASSERT(!result->IsFailure());
+    Object* result =
+        Heap::new_space()->AllocateRaw(object_size)->ToObjectUnchecked();
     *slot = MigrateObject(object, HeapObject::cast(result), object_size);
     return;
   }
 
 
   static inline void EvacuateFixedArray(Map* map,
                                         HeapObject** slot,
                                         HeapObject* object) {
     int object_size = FixedArray::BodyDescriptor::SizeOf(map, object);
     EvacuateObject<POINTER_OBJECT, UNKNOWN_SIZE>(map,
@@ skipping 101 matching lines @@
   Map* map = first_word.ToMap();
   ScavengingVisitor::Scavenge(map, p, object);
 }
 
 
 void Heap::ScavengePointer(HeapObject** p) {
   ScavengeObject(p, *p);
 }
 
 
-Object* Heap::AllocatePartialMap(InstanceType instance_type,
-                                 int instance_size) {
-  Object* result = AllocateRawMap();
-  if (result->IsFailure()) return result;
+MaybeObject* Heap::AllocatePartialMap(InstanceType instance_type,
+                                      int instance_size) {
+  Object* result;
+  { MaybeObject* maybe_result = AllocateRawMap();
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   // Map::cast cannot be used due to uninitialized map field.
   reinterpret_cast<Map*>(result)->set_map(raw_unchecked_meta_map());
   reinterpret_cast<Map*>(result)->set_instance_type(instance_type);
   reinterpret_cast<Map*>(result)->set_instance_size(instance_size);
   reinterpret_cast<Map*>(result)->
       set_visitor_id(
           StaticVisitorBase::GetVisitorId(instance_type, instance_size));
   reinterpret_cast<Map*>(result)->set_inobject_properties(0);
   reinterpret_cast<Map*>(result)->set_pre_allocated_property_fields(0);
   reinterpret_cast<Map*>(result)->set_unused_property_fields(0);
   reinterpret_cast<Map*>(result)->set_bit_field(0);
   reinterpret_cast<Map*>(result)->set_bit_field2(0);
   return result;
 }
 
 
-Object* Heap::AllocateMap(InstanceType instance_type, int instance_size) {
-  Object* result = AllocateRawMap();
-  if (result->IsFailure()) return result;
+MaybeObject* Heap::AllocateMap(InstanceType instance_type, int instance_size) {
+  Object* result;
+  { MaybeObject* maybe_result = AllocateRawMap();
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   Map* map = reinterpret_cast<Map*>(result);
   map->set_map(meta_map());
   map->set_instance_type(instance_type);
   map->set_visitor_id(
       StaticVisitorBase::GetVisitorId(instance_type, instance_size));
   map->set_prototype(null_value());
   map->set_constructor(null_value());
   map->set_instance_size(instance_size);
   map->set_inobject_properties(0);
   map->set_pre_allocated_property_fields(0);
   map->set_instance_descriptors(empty_descriptor_array());
   map->set_code_cache(empty_fixed_array());
   map->set_unused_property_fields(0);
   map->set_bit_field(0);
   map->set_bit_field2((1 << Map::kIsExtensible) | (1 << Map::kHasFastElements));
 
   // If the map object is aligned fill the padding area with Smi 0 objects.
   if (Map::kPadStart < Map::kSize) {
     memset(reinterpret_cast<byte*>(map) + Map::kPadStart - kHeapObjectTag,
            0,
            Map::kSize - Map::kPadStart);
   }
   return map;
 }
 
 
-Object* Heap::AllocateCodeCache() {
-  Object* result = AllocateStruct(CODE_CACHE_TYPE);
-  if (result->IsFailure()) return result;
+MaybeObject* Heap::AllocateCodeCache() {
+  Object* result;
+  { MaybeObject* maybe_result = AllocateStruct(CODE_CACHE_TYPE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   CodeCache* code_cache = CodeCache::cast(result);
   code_cache->set_default_cache(empty_fixed_array());
   code_cache->set_normal_type_cache(undefined_value());
   return code_cache;
 }
 
 
 const Heap::StringTypeTable Heap::string_type_table[] = {
 #define STRING_TYPE_ELEMENT(type, size, name, camel_name)                      \
   {type, size, k##camel_name##MapRootIndex},
@@ skipping 12 matching lines @@
 
 const Heap::StructTable Heap::struct_table[] = {
 #define STRUCT_TABLE_ELEMENT(NAME, Name, name)                                 \
   { NAME##_TYPE, Name::kSize, k##Name##MapRootIndex },
   STRUCT_LIST(STRUCT_TABLE_ELEMENT)
 #undef STRUCT_TABLE_ELEMENT
 };
 
 
 bool Heap::CreateInitialMaps() {
-  Object* obj = AllocatePartialMap(MAP_TYPE, Map::kSize);
-  if (obj->IsFailure()) return false;
+  Object* obj;
+  { MaybeObject* maybe_obj = AllocatePartialMap(MAP_TYPE, Map::kSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   // Map::cast cannot be used due to uninitialized map field.
   Map* new_meta_map = reinterpret_cast<Map*>(obj);
   set_meta_map(new_meta_map);
   new_meta_map->set_map(new_meta_map);
 
-  obj = AllocatePartialMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocatePartialMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_fixed_array_map(Map::cast(obj));
 
-  obj = AllocatePartialMap(ODDBALL_TYPE, Oddball::kSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocatePartialMap(ODDBALL_TYPE, Oddball::kSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_oddball_map(Map::cast(obj));
 
   // Allocate the empty array.
-  obj = AllocateEmptyFixedArray();
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateEmptyFixedArray();
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_empty_fixed_array(FixedArray::cast(obj));
 
-  obj = Allocate(oddball_map(), OLD_DATA_SPACE);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = Allocate(oddball_map(), OLD_DATA_SPACE);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_null_value(obj);
 
   // Allocate the empty descriptor array.
-  obj = AllocateEmptyFixedArray();
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateEmptyFixedArray();
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_empty_descriptor_array(DescriptorArray::cast(obj));
 
   // Fix the instance_descriptors for the existing maps.
   meta_map()->set_instance_descriptors(empty_descriptor_array());
   meta_map()->set_code_cache(empty_fixed_array());
 
   fixed_array_map()->set_instance_descriptors(empty_descriptor_array());
   fixed_array_map()->set_code_cache(empty_fixed_array());
 
   oddball_map()->set_instance_descriptors(empty_descriptor_array());
   oddball_map()->set_code_cache(empty_fixed_array());
 
   // Fix prototype object for existing maps.
   meta_map()->set_prototype(null_value());
   meta_map()->set_constructor(null_value());
 
   fixed_array_map()->set_prototype(null_value());
   fixed_array_map()->set_constructor(null_value());
 
   oddball_map()->set_prototype(null_value());
   oddball_map()->set_constructor(null_value());
 
-  obj = AllocateMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocateMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_fixed_cow_array_map(Map::cast(obj));
   ASSERT(fixed_array_map() != fixed_cow_array_map());
 
-  obj = AllocateMap(HEAP_NUMBER_TYPE, HeapNumber::kSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(HEAP_NUMBER_TYPE, HeapNumber::kSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_heap_number_map(Map::cast(obj));
 
-  obj = AllocateMap(PROXY_TYPE, Proxy::kSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(PROXY_TYPE, Proxy::kSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_proxy_map(Map::cast(obj));
 
   for (unsigned i = 0; i < ARRAY_SIZE(string_type_table); i++) {
     const StringTypeTable& entry = string_type_table[i];
-    obj = AllocateMap(entry.type, entry.size);
-    if (obj->IsFailure()) return false;
+    { MaybeObject* maybe_obj = AllocateMap(entry.type, entry.size);
+      if (!maybe_obj->ToObject(&obj)) return false;
+    }
     roots_[entry.index] = Map::cast(obj);
   }
 
-  obj = AllocateMap(STRING_TYPE, kVariableSizeSentinel);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(STRING_TYPE, kVariableSizeSentinel);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_undetectable_string_map(Map::cast(obj));
   Map::cast(obj)->set_is_undetectable();
 
-  obj = AllocateMap(ASCII_STRING_TYPE, kVariableSizeSentinel);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocateMap(ASCII_STRING_TYPE, kVariableSizeSentinel);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_undetectable_ascii_string_map(Map::cast(obj));
   Map::cast(obj)->set_is_undetectable();
 
-  obj = AllocateMap(BYTE_ARRAY_TYPE, kVariableSizeSentinel);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocateMap(BYTE_ARRAY_TYPE, kVariableSizeSentinel);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_byte_array_map(Map::cast(obj));
 
-  obj = AllocateMap(PIXEL_ARRAY_TYPE, PixelArray::kAlignedSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocateMap(PIXEL_ARRAY_TYPE, PixelArray::kAlignedSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_pixel_array_map(Map::cast(obj));
 
-  obj = AllocateMap(EXTERNAL_BYTE_ARRAY_TYPE,
-                    ExternalArray::kAlignedSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(EXTERNAL_BYTE_ARRAY_TYPE,
+                                         ExternalArray::kAlignedSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_external_byte_array_map(Map::cast(obj));
 
-  obj = AllocateMap(EXTERNAL_UNSIGNED_BYTE_ARRAY_TYPE,
-                    ExternalArray::kAlignedSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(EXTERNAL_UNSIGNED_BYTE_ARRAY_TYPE,
+                                         ExternalArray::kAlignedSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_external_unsigned_byte_array_map(Map::cast(obj));
 
-  obj = AllocateMap(EXTERNAL_SHORT_ARRAY_TYPE,
-                    ExternalArray::kAlignedSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(EXTERNAL_SHORT_ARRAY_TYPE,
+                                         ExternalArray::kAlignedSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_external_short_array_map(Map::cast(obj));
 
-  obj = AllocateMap(EXTERNAL_UNSIGNED_SHORT_ARRAY_TYPE,
-                    ExternalArray::kAlignedSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(EXTERNAL_UNSIGNED_SHORT_ARRAY_TYPE,
+                                         ExternalArray::kAlignedSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_external_unsigned_short_array_map(Map::cast(obj));
 
-  obj = AllocateMap(EXTERNAL_INT_ARRAY_TYPE,
-                    ExternalArray::kAlignedSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(EXTERNAL_INT_ARRAY_TYPE,
+                                         ExternalArray::kAlignedSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_external_int_array_map(Map::cast(obj));
 
-  obj = AllocateMap(EXTERNAL_UNSIGNED_INT_ARRAY_TYPE,
-                    ExternalArray::kAlignedSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(EXTERNAL_UNSIGNED_INT_ARRAY_TYPE,
+                                         ExternalArray::kAlignedSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_external_unsigned_int_array_map(Map::cast(obj));
 
-  obj = AllocateMap(EXTERNAL_FLOAT_ARRAY_TYPE,
-                    ExternalArray::kAlignedSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(EXTERNAL_FLOAT_ARRAY_TYPE,
+                                         ExternalArray::kAlignedSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_external_float_array_map(Map::cast(obj));
 
-  obj = AllocateMap(CODE_TYPE, kVariableSizeSentinel);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(CODE_TYPE, kVariableSizeSentinel);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_code_map(Map::cast(obj));
 
-  obj = AllocateMap(JS_GLOBAL_PROPERTY_CELL_TYPE,
-                    JSGlobalPropertyCell::kSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(JS_GLOBAL_PROPERTY_CELL_TYPE,
+                                         JSGlobalPropertyCell::kSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_global_property_cell_map(Map::cast(obj));
 
-  obj = AllocateMap(FILLER_TYPE, kPointerSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(FILLER_TYPE, kPointerSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_one_pointer_filler_map(Map::cast(obj));
 
-  obj = AllocateMap(FILLER_TYPE, 2 * kPointerSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(FILLER_TYPE, 2 * kPointerSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_two_pointer_filler_map(Map::cast(obj));
 
   for (unsigned i = 0; i < ARRAY_SIZE(struct_table); i++) {
     const StructTable& entry = struct_table[i];
-    obj = AllocateMap(entry.type, entry.size);
-    if (obj->IsFailure()) return false;
+    { MaybeObject* maybe_obj = AllocateMap(entry.type, entry.size);
+      if (!maybe_obj->ToObject(&obj)) return false;
+    }
     roots_[entry.index] = Map::cast(obj);
   }
 
-  obj = AllocateMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocateMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_hash_table_map(Map::cast(obj));
 
-  obj = AllocateMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocateMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_context_map(Map::cast(obj));
 
-  obj = AllocateMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocateMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_catch_context_map(Map::cast(obj));
 
-  obj = AllocateMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocateMap(FIXED_ARRAY_TYPE, kVariableSizeSentinel);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   Map* global_context_map = Map::cast(obj);
   global_context_map->set_visitor_id(StaticVisitorBase::kVisitGlobalContext);
   set_global_context_map(global_context_map);
 
-  obj = AllocateMap(SHARED_FUNCTION_INFO_TYPE,
-                    SharedFunctionInfo::kAlignedSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(SHARED_FUNCTION_INFO_TYPE,
+                                         SharedFunctionInfo::kAlignedSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_shared_function_info_map(Map::cast(obj));
 
   ASSERT(!Heap::InNewSpace(Heap::empty_fixed_array()));
   return true;
 }
 
 
-Object* Heap::AllocateHeapNumber(double value, PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateHeapNumber(double value, PretenureFlag pretenure) {
   // Statically ensure that it is safe to allocate heap numbers in paged
   // spaces.
   STATIC_ASSERT(HeapNumber::kSize <= Page::kMaxHeapObjectSize);
   AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
 
-  Object* result = AllocateRaw(HeapNumber::kSize, space, OLD_DATA_SPACE);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result =
+        AllocateRaw(HeapNumber::kSize, space, OLD_DATA_SPACE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   HeapObject::cast(result)->set_map(heap_number_map());
   HeapNumber::cast(result)->set_value(value);
   return result;
 }
 
 
-Object* Heap::AllocateHeapNumber(double value) {
+MaybeObject* Heap::AllocateHeapNumber(double value) {
   // Use general version, if we're forced to always allocate.
   if (always_allocate()) return AllocateHeapNumber(value, TENURED);
 
   // This version of AllocateHeapNumber is optimized for
   // allocation in new space.
   STATIC_ASSERT(HeapNumber::kSize <= Page::kMaxHeapObjectSize);
   ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
-  Object* result = new_space_.AllocateRaw(HeapNumber::kSize);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = new_space_.AllocateRaw(HeapNumber::kSize);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   HeapObject::cast(result)->set_map(heap_number_map());
   HeapNumber::cast(result)->set_value(value);
   return result;
 }
 
 
-Object* Heap::AllocateJSGlobalPropertyCell(Object* value) {
-  Object* result = AllocateRawCell();
-  if (result->IsFailure()) return result;
+MaybeObject* Heap::AllocateJSGlobalPropertyCell(Object* value) {
+  Object* result;
+  { MaybeObject* maybe_result = AllocateRawCell();
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   HeapObject::cast(result)->set_map(global_property_cell_map());
   JSGlobalPropertyCell::cast(result)->set_value(value);
   return result;
 }
 
 
-Object* Heap::CreateOddball(const char* to_string,
-                            Object* to_number) {
-  Object* result = Allocate(oddball_map(), OLD_DATA_SPACE);
-  if (result->IsFailure()) return result;
+MaybeObject* Heap::CreateOddball(const char* to_string,
+                                 Object* to_number) {
+  Object* result;
+  { MaybeObject* maybe_result = Allocate(oddball_map(), OLD_DATA_SPACE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   return Oddball::cast(result)->Initialize(to_string, to_number);
 }
 
 
 bool Heap::CreateApiObjects() {
   Object* obj;
 
-  obj = AllocateMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_neander_map(Map::cast(obj));
 
-  obj = Heap::AllocateJSObjectFromMap(neander_map());
-  if (obj->IsFailure()) return false;
-  Object* elements = AllocateFixedArray(2);
-  if (elements->IsFailure()) return false;
+  { MaybeObject* maybe_obj = Heap::AllocateJSObjectFromMap(neander_map());
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
+  Object* elements;
+  { MaybeObject* maybe_elements = AllocateFixedArray(2);
+    if (!maybe_elements->ToObject(&elements)) return false;
+  }
   FixedArray::cast(elements)->set(0, Smi::FromInt(0));
   JSObject::cast(obj)->set_elements(FixedArray::cast(elements));
   set_message_listeners(JSObject::cast(obj));
 
   return true;
 }
 
 
 void Heap::CreateCEntryStub() {
   CEntryStub stub(1);
@@ skipping 41 matching lines @@
 #if V8_TARGET_ARCH_ARM && !V8_INTERPRETED_REGEXP
   Heap::CreateRegExpCEntryStub();
 #endif
 }
 
 
 bool Heap::CreateInitialObjects() {
   Object* obj;
 
   // The -0 value must be set before NumberFromDouble works.
-  obj = AllocateHeapNumber(-0.0, TENURED);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateHeapNumber(-0.0, TENURED);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_minus_zero_value(obj);
   ASSERT(signbit(minus_zero_value()->Number()) != 0);
 
-  obj = AllocateHeapNumber(OS::nan_value(), TENURED);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateHeapNumber(OS::nan_value(), TENURED);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_nan_value(obj);
 
-  obj = Allocate(oddball_map(), OLD_DATA_SPACE);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = Allocate(oddball_map(), OLD_DATA_SPACE);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_undefined_value(obj);
   ASSERT(!InNewSpace(undefined_value()));
 
   // Allocate initial symbol table.
-  obj = SymbolTable::Allocate(kInitialSymbolTableSize);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = SymbolTable::Allocate(kInitialSymbolTableSize);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   // Don't use set_symbol_table() due to asserts.
   roots_[kSymbolTableRootIndex] = obj;
 
   // Assign the print strings for oddballs after creating symboltable.
-  Object* symbol = LookupAsciiSymbol("undefined");
-  if (symbol->IsFailure()) return false;
+  Object* symbol;
+  { MaybeObject* maybe_symbol = LookupAsciiSymbol("undefined");
+    if (!maybe_symbol->ToObject(&symbol)) return false;
+  }
   Oddball::cast(undefined_value())->set_to_string(String::cast(symbol));
   Oddball::cast(undefined_value())->set_to_number(nan_value());
 
   // Allocate the null_value
-  obj = Oddball::cast(null_value())->Initialize("null", Smi::FromInt(0));
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        Oddball::cast(null_value())->Initialize("null", Smi::FromInt(0));
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
 
-  obj = CreateOddball("true", Smi::FromInt(1));
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = CreateOddball("true", Smi::FromInt(1));
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_true_value(obj);
 
-  obj = CreateOddball("false", Smi::FromInt(0));
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = CreateOddball("false", Smi::FromInt(0));
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_false_value(obj);
 
-  obj = CreateOddball("hole", Smi::FromInt(-1));
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = CreateOddball("hole", Smi::FromInt(-1));
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_the_hole_value(obj);
 
-  obj = CreateOddball("no_interceptor_result_sentinel", Smi::FromInt(-2));
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        CreateOddball("no_interceptor_result_sentinel", Smi::FromInt(-2));
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_no_interceptor_result_sentinel(obj);
 
-  obj = CreateOddball("termination_exception", Smi::FromInt(-3));
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        CreateOddball("termination_exception", Smi::FromInt(-3));
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_termination_exception(obj);
 
   // Allocate the empty string.
-  obj = AllocateRawAsciiString(0, TENURED);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateRawAsciiString(0, TENURED);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_empty_string(String::cast(obj));
 
   for (unsigned i = 0; i < ARRAY_SIZE(constant_symbol_table); i++) {
-    obj = LookupAsciiSymbol(constant_symbol_table[i].contents);
-    if (obj->IsFailure()) return false;
+    { MaybeObject* maybe_obj =
+          LookupAsciiSymbol(constant_symbol_table[i].contents);
+      if (!maybe_obj->ToObject(&obj)) return false;
+    }
     roots_[constant_symbol_table[i].index] = String::cast(obj);
   }
 
   // Allocate the hidden symbol which is used to identify the hidden properties
   // in JSObjects. The hash code has a special value so that it will not match
   // the empty string when searching for the property. It cannot be part of the
   // loop above because it needs to be allocated manually with the special
   // hash code in place. The hash code for the hidden_symbol is zero to ensure
   // that it will always be at the first entry in property descriptors.
-  obj = AllocateSymbol(CStrVector(""), 0, String::kZeroHash);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocateSymbol(CStrVector(""), 0, String::kZeroHash);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   hidden_symbol_ = String::cast(obj);
 
   // Allocate the proxy for __proto__.
-  obj = AllocateProxy((Address) &Accessors::ObjectPrototype);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocateProxy((Address) &Accessors::ObjectPrototype);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_prototype_accessors(Proxy::cast(obj));
 
   // Allocate the code_stubs dictionary. The initial size is set to avoid
   // expanding the dictionary during bootstrapping.
-  obj = NumberDictionary::Allocate(128);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = NumberDictionary::Allocate(128);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_code_stubs(NumberDictionary::cast(obj));
 
   // Allocate the non_monomorphic_cache used in stub-cache.cc. The initial size
   // is set to avoid expanding the dictionary during bootstrapping.
-  obj = NumberDictionary::Allocate(64);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = NumberDictionary::Allocate(64);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_non_monomorphic_cache(NumberDictionary::cast(obj));
 
   set_instanceof_cache_function(Smi::FromInt(0));
   set_instanceof_cache_map(Smi::FromInt(0));
   set_instanceof_cache_answer(Smi::FromInt(0));
 
   CreateFixedStubs();
 
   // Allocate the dictionary of intrinsic function names.
-  obj = StringDictionary::Allocate(Runtime::kNumFunctions);
-  if (obj->IsFailure()) return false;
-  obj = Runtime::InitializeIntrinsicFunctionNames(obj);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = StringDictionary::Allocate(Runtime::kNumFunctions);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
+  { MaybeObject* maybe_obj = Runtime::InitializeIntrinsicFunctionNames(obj);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_intrinsic_function_names(StringDictionary::cast(obj));
 
   if (InitializeNumberStringCache()->IsFailure()) return false;
 
   // Allocate cache for single character ASCII strings.
-  obj = AllocateFixedArray(String::kMaxAsciiCharCode + 1, TENURED);
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj =
+        AllocateFixedArray(String::kMaxAsciiCharCode + 1, TENURED);
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_single_character_string_cache(FixedArray::cast(obj));
 
   // Allocate cache for external strings pointing to native source code.
-  obj = AllocateFixedArray(Natives::GetBuiltinsCount());
-  if (obj->IsFailure()) return false;
+  { MaybeObject* maybe_obj = AllocateFixedArray(Natives::GetBuiltinsCount());
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
   set_natives_source_cache(FixedArray::cast(obj));
 
   // Handling of script id generation is in Factory::NewScript.
   set_last_script_id(undefined_value());
 
   // Initialize keyed lookup cache.
   KeyedLookupCache::Clear();
 
   // Initialize context slot cache.
   ContextSlotCache::Clear();
 
   // Initialize descriptor cache.
   DescriptorLookupCache::Clear();
 
   // Initialize compilation cache.
   CompilationCache::Clear();
 
   return true;
 }
 
 
-Object* Heap::InitializeNumberStringCache() {
+MaybeObject* Heap::InitializeNumberStringCache() {
   // Compute the size of the number string cache based on the max heap size.
   // max_semispace_size_ == 512 KB => number_string_cache_size = 32.
   // max_semispace_size_ ==   8 MB => number_string_cache_size = 16KB.
   int number_string_cache_size = max_semispace_size_ / 512;
   number_string_cache_size = Max(32, Min(16*KB, number_string_cache_size));
-  Object* obj = AllocateFixedArray(number_string_cache_size * 2, TENURED);
-  if (!obj->IsFailure()) set_number_string_cache(FixedArray::cast(obj));
-  return obj;
+  Object* obj;
+  MaybeObject* maybe_obj =
+      AllocateFixedArray(number_string_cache_size * 2, TENURED);
+  if (maybe_obj->ToObject(&obj)) set_number_string_cache(FixedArray::cast(obj));
+  return maybe_obj;
 }
 
 
 void Heap::FlushNumberStringCache() {
   // Flush the number to string cache.
   int len = number_string_cache()->length();
   for (int i = 0; i < len; i++) {
     number_string_cache()->set_undefined(i);
   }
 }
@@ skipping 37 matching lines @@
     hash = smi_get_hash(Smi::cast(number)) & mask;
     number_string_cache()->set(hash * 2, Smi::cast(number));
   } else {
     hash = double_get_hash(number->Number()) & mask;
     number_string_cache()->set(hash * 2, number);
   }
   number_string_cache()->set(hash * 2 + 1, string);
 }
 
 
-Object* Heap::NumberToString(Object* number, bool check_number_string_cache) {
+MaybeObject* Heap::NumberToString(Object* number,
+                                  bool check_number_string_cache) {
   Counters::number_to_string_runtime.Increment();
   if (check_number_string_cache) {
     Object* cached = GetNumberStringCache(number);
     if (cached != undefined_value()) {
       return cached;
     }
   }
 
   char arr[100];
   Vector<char> buffer(arr, ARRAY_SIZE(arr));
   const char* str;
   if (number->IsSmi()) {
     int num = Smi::cast(number)->value();
     str = IntToCString(num, buffer);
   } else {
     double num = HeapNumber::cast(number)->value();
     str = DoubleToCString(num, buffer);
   }
-  Object* result = AllocateStringFromAscii(CStrVector(str));
 
-  if (!result->IsFailure()) {
-    SetNumberStringCache(number, String::cast(result));
+  Object* js_string;
+  MaybeObject* maybe_js_string = AllocateStringFromAscii(CStrVector(str));
+  if (maybe_js_string->ToObject(&js_string)) {
+    SetNumberStringCache(number, String::cast(js_string));
   }
-  return result;
+  return maybe_js_string;
 }
 
 
 Map* Heap::MapForExternalArrayType(ExternalArrayType array_type) {
   return Map::cast(roots_[RootIndexForExternalArrayType(array_type)]);
 }
 
 
 Heap::RootListIndex Heap::RootIndexForExternalArrayType(
     ExternalArrayType array_type) {
@@ skipping 12 matching lines @@
       return kExternalUnsignedIntArrayMapRootIndex;
     case kExternalFloatArray:
       return kExternalFloatArrayMapRootIndex;
     default:
       UNREACHABLE();
       return kUndefinedValueRootIndex;
   }
 }
 
 
-Object* Heap::NumberFromDouble(double value, PretenureFlag pretenure) {
+MaybeObject* Heap::NumberFromDouble(double value, PretenureFlag pretenure) {
   // We need to distinguish the minus zero value and this cannot be
   // done after conversion to int. Doing this by comparing bit
   // patterns is faster than using fpclassify() et al.
   static const DoubleRepresentation minus_zero(-0.0);
 
   DoubleRepresentation rep(value);
   if (rep.bits == minus_zero.bits) {
     return AllocateHeapNumber(-0.0, pretenure);
   }
 
   int int_value = FastD2I(value);
   if (value == int_value && Smi::IsValid(int_value)) {
     return Smi::FromInt(int_value);
   }
 
   // Materialize the value in the heap.
   return AllocateHeapNumber(value, pretenure);
 }
 
 
-Object* Heap::AllocateProxy(Address proxy, PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateProxy(Address proxy, PretenureFlag pretenure) {
   // Statically ensure that it is safe to allocate proxies in paged spaces.
   STATIC_ASSERT(Proxy::kSize <= Page::kMaxHeapObjectSize);
   AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
-  Object* result = Allocate(proxy_map(), space);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = Allocate(proxy_map(), space);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   Proxy::cast(result)->set_proxy(proxy);
   return result;
 }
 
 
-Object* Heap::AllocateSharedFunctionInfo(Object* name) {
-  Object* result = Allocate(shared_function_info_map(), OLD_POINTER_SPACE);
-  if (result->IsFailure()) return result;
+MaybeObject* Heap::AllocateSharedFunctionInfo(Object* name) {
+  Object* result;
+  { MaybeObject* maybe_result =
+        Allocate(shared_function_info_map(), OLD_POINTER_SPACE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   SharedFunctionInfo* share = SharedFunctionInfo::cast(result);
   share->set_name(name);
   Code* illegal = Builtins::builtin(Builtins::Illegal);
   share->set_code(illegal);
   share->set_scope_info(SerializedScopeInfo::Empty());
   Code* construct_stub = Builtins::builtin(Builtins::JSConstructStubGeneric);
   share->set_construct_stub(construct_stub);
   share->set_expected_nof_properties(0);
   share->set_length(0);
@@ skipping 15 matching lines @@
 }
 
 
 // Returns true for a character in a range.  Both limits are inclusive.
 static inline bool Between(uint32_t character, uint32_t from, uint32_t to) {
   // This makes uses of the the unsigned wraparound.
   return character - from <= to - from;
 }
 
 
-static inline Object* MakeOrFindTwoCharacterString(uint32_t c1, uint32_t c2) {
+MUST_USE_RESULT static inline MaybeObject* MakeOrFindTwoCharacterString(
+    uint32_t c1,
+    uint32_t c2) {
   String* symbol;
   // Numeric strings have a different hash algorithm not known by
   // LookupTwoCharsSymbolIfExists, so we skip this step for such strings.
   if ((!Between(c1, '0', '9') || !Between(c2, '0', '9')) &&
       Heap::symbol_table()->LookupTwoCharsSymbolIfExists(c1, c2, &symbol)) {
     return symbol;
   // Now we know the length is 2, we might as well make use of that fact
   // when building the new string.
   } else if ((c1 | c2) <= String::kMaxAsciiCharCodeU) {  // We can do this
     ASSERT(IsPowerOf2(String::kMaxAsciiCharCodeU + 1));  // because of this.
-    Object* result = Heap::AllocateRawAsciiString(2);
-    if (result->IsFailure()) return result;
+    Object* result;
+    { MaybeObject* maybe_result = Heap::AllocateRawAsciiString(2);
+      if (!maybe_result->ToObject(&result)) return maybe_result;
+    }
     char* dest = SeqAsciiString::cast(result)->GetChars();
     dest[0] = c1;
     dest[1] = c2;
     return result;
   } else {
-    Object* result = Heap::AllocateRawTwoByteString(2);
-    if (result->IsFailure()) return result;
+    Object* result;
+    { MaybeObject* maybe_result = Heap::AllocateRawTwoByteString(2);
+      if (!maybe_result->ToObject(&result)) return maybe_result;
+    }
     uc16* dest = SeqTwoByteString::cast(result)->GetChars();
     dest[0] = c1;
     dest[1] = c2;
     return result;
   }
 }
 
 
-Object* Heap::AllocateConsString(String* first, String* second) {
+MaybeObject* Heap::AllocateConsString(String* first, String* second) {
   int first_length = first->length();
   if (first_length == 0) {
     return second;
   }
 
   int second_length = second->length();
   if (second_length == 0) {
     return first;
   }
 
@@ skipping 29 matching lines @@
     if (is_ascii_data_in_two_byte_string) {
       Counters::string_add_runtime_ext_to_ascii.Increment();
     }
   }
 
   // If the resulting string is small make a flat string.
   if (length < String::kMinNonFlatLength) {
     ASSERT(first->IsFlat());
     ASSERT(second->IsFlat());
     if (is_ascii) {
-      Object* result = AllocateRawAsciiString(length);
-      if (result->IsFailure()) return result;
+      Object* result;
+      { MaybeObject* maybe_result = AllocateRawAsciiString(length);
+        if (!maybe_result->ToObject(&result)) return maybe_result;
+      }
       // Copy the characters into the new object.
       char* dest = SeqAsciiString::cast(result)->GetChars();
       // Copy first part.
       const char* src;
       if (first->IsExternalString()) {
         src = ExternalAsciiString::cast(first)->resource()->data();
       } else {
         src = SeqAsciiString::cast(first)->GetChars();
       }
       for (int i = 0; i < first_length; i++) *dest++ = src[i];
       // Copy second part.
       if (second->IsExternalString()) {
         src = ExternalAsciiString::cast(second)->resource()->data();
       } else {
         src = SeqAsciiString::cast(second)->GetChars();
       }
       for (int i = 0; i < second_length; i++) *dest++ = src[i];
       return result;
     } else {
       if (is_ascii_data_in_two_byte_string) {
-        Object* result = AllocateRawAsciiString(length);
-        if (result->IsFailure()) return result;
+        Object* result;
+        { MaybeObject* maybe_result = AllocateRawAsciiString(length);
+          if (!maybe_result->ToObject(&result)) return maybe_result;
+        }
         // Copy the characters into the new object.
         char* dest = SeqAsciiString::cast(result)->GetChars();
         String::WriteToFlat(first, dest, 0, first_length);
         String::WriteToFlat(second, dest + first_length, 0, second_length);
         return result;
       }
 
-      Object* result = AllocateRawTwoByteString(length);
-      if (result->IsFailure()) return result;
+      Object* result;
+      { MaybeObject* maybe_result = AllocateRawTwoByteString(length);
+        if (!maybe_result->ToObject(&result)) return maybe_result;
+      }
       // Copy the characters into the new object.
       uc16* dest = SeqTwoByteString::cast(result)->GetChars();
       String::WriteToFlat(first, dest, 0, first_length);
       String::WriteToFlat(second, dest + first_length, 0, second_length);
       return result;
     }
   }
 
   Map* map = (is_ascii || is_ascii_data_in_two_byte_string) ?
       cons_ascii_string_map() : cons_string_map();
 
-  Object* result = Allocate(map, NEW_SPACE);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = Allocate(map, NEW_SPACE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   AssertNoAllocation no_gc;
   ConsString* cons_string = ConsString::cast(result);
   WriteBarrierMode mode = cons_string->GetWriteBarrierMode(no_gc);
   cons_string->set_length(length);
   cons_string->set_hash_field(String::kEmptyHashField);
   cons_string->set_first(first, mode);
   cons_string->set_second(second, mode);
   return result;
 }
 
 
-Object* Heap::AllocateSubString(String* buffer,
+MaybeObject* Heap::AllocateSubString(String* buffer,
                                 int start,
                                 int end,
                                 PretenureFlag pretenure) {
   int length = end - start;
 
   if (length == 1) {
     return Heap::LookupSingleCharacterStringFromCode(
         buffer->Get(start));
   } else if (length == 2) {
     // Optimization for 2-byte strings often used as keys in a decompression
     // dictionary.  Check whether we already have the string in the symbol
     // table to prevent creation of many unneccesary strings.
     unsigned c1 = buffer->Get(start);
     unsigned c2 = buffer->Get(start + 1);
     return MakeOrFindTwoCharacterString(c1, c2);
   }
 
   // Make an attempt to flatten the buffer to reduce access time.
   buffer = buffer->TryFlattenGetString();
 
-  Object* result = buffer->IsAsciiRepresentation()
-      ? AllocateRawAsciiString(length, pretenure )
-      : AllocateRawTwoByteString(length, pretenure);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = buffer->IsAsciiRepresentation()
+                   ? AllocateRawAsciiString(length, pretenure )
+                   : AllocateRawTwoByteString(length, pretenure);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   String* string_result = String::cast(result);
   // Copy the characters into the new object.
   if (buffer->IsAsciiRepresentation()) {
     ASSERT(string_result->IsAsciiRepresentation());
     char* dest = SeqAsciiString::cast(string_result)->GetChars();
     String::WriteToFlat(buffer, dest, start, end);
   } else {
     ASSERT(string_result->IsTwoByteRepresentation());
     uc16* dest = SeqTwoByteString::cast(string_result)->GetChars();
     String::WriteToFlat(buffer, dest, start, end);
   }
 
   return result;
 }
 
 
-Object* Heap::AllocateExternalStringFromAscii(
+MaybeObject* Heap::AllocateExternalStringFromAscii(
     ExternalAsciiString::Resource* resource) {
   size_t length = resource->length();
   if (length > static_cast<size_t>(String::kMaxLength)) {
     Top::context()->mark_out_of_memory();
     return Failure::OutOfMemoryException();
   }
 
   Map* map = external_ascii_string_map();
-  Object* result = Allocate(map, NEW_SPACE);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = Allocate(map, NEW_SPACE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   ExternalAsciiString* external_string = ExternalAsciiString::cast(result);
   external_string->set_length(static_cast<int>(length));
   external_string->set_hash_field(String::kEmptyHashField);
   external_string->set_resource(resource);
 
   return result;
 }
 
 
-Object* Heap::AllocateExternalStringFromTwoByte(
+MaybeObject* Heap::AllocateExternalStringFromTwoByte(
     ExternalTwoByteString::Resource* resource) {
   size_t length = resource->length();
   if (length > static_cast<size_t>(String::kMaxLength)) {
     Top::context()->mark_out_of_memory();
     return Failure::OutOfMemoryException();
   }
 
   // For small strings we check whether the resource contains only
   // ascii characters.  If yes, we use a different string map.
   bool is_ascii = true;
   if (length >= static_cast<size_t>(String::kMinNonFlatLength)) {
     is_ascii = false;
   } else {
     const uc16* data = resource->data();
     for (size_t i = 0; i < length; i++) {
       if (data[i] > String::kMaxAsciiCharCode) {
         is_ascii = false;
         break;
       }
     }
   }
 
   Map* map = is_ascii ?
       Heap::external_string_with_ascii_data_map() : Heap::external_string_map();
-  Object* result = Allocate(map, NEW_SPACE);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = Allocate(map, NEW_SPACE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   ExternalTwoByteString* external_string = ExternalTwoByteString::cast(result);
   external_string->set_length(static_cast<int>(length));
   external_string->set_hash_field(String::kEmptyHashField);
   external_string->set_resource(resource);
 
   return result;
 }
 
 
-Object* Heap::LookupSingleCharacterStringFromCode(uint16_t code) {
+MaybeObject* Heap::LookupSingleCharacterStringFromCode(uint16_t code) {
   if (code <= String::kMaxAsciiCharCode) {
     Object* value = Heap::single_character_string_cache()->get(code);
     if (value != Heap::undefined_value()) return value;
 
     char buffer[1];
     buffer[0] = static_cast<char>(code);
-    Object* result = LookupSymbol(Vector<const char>(buffer, 1));
+    Object* result;
+    MaybeObject* maybe_result = LookupSymbol(Vector<const char>(buffer, 1));
 
-    if (result->IsFailure()) return result;
+    if (!maybe_result->ToObject(&result)) return maybe_result;
     Heap::single_character_string_cache()->set(code, result);
     return result;
   }
 
-  Object* result = Heap::AllocateRawTwoByteString(1);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = Heap::AllocateRawTwoByteString(1);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   String* answer = String::cast(result);
   answer->Set(0, code);
   return answer;
 }
 
 
-Object* Heap::AllocateByteArray(int length, PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateByteArray(int length, PretenureFlag pretenure) {
   if (length < 0 || length > ByteArray::kMaxLength) {
     return Failure::OutOfMemoryException();
   }
   if (pretenure == NOT_TENURED) {
     return AllocateByteArray(length);
   }
   int size = ByteArray::SizeFor(length);
-  Object* result = (size <= MaxObjectSizeInPagedSpace())
-      ? old_data_space_->AllocateRaw(size)
-      : lo_space_->AllocateRaw(size);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = (size <= MaxObjectSizeInPagedSpace())
+                   ? old_data_space_->AllocateRaw(size)
+                   : lo_space_->AllocateRaw(size);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   reinterpret_cast<ByteArray*>(result)->set_map(byte_array_map());
   reinterpret_cast<ByteArray*>(result)->set_length(length);
   return result;
 }
 
 
-Object* Heap::AllocateByteArray(int length) {
+MaybeObject* Heap::AllocateByteArray(int length) {
   if (length < 0 || length > ByteArray::kMaxLength) {
     return Failure::OutOfMemoryException();
   }
   int size = ByteArray::SizeFor(length);
   AllocationSpace space =
       (size > MaxObjectSizeInPagedSpace()) ? LO_SPACE : NEW_SPACE;
-  Object* result = AllocateRaw(size, space, OLD_DATA_SPACE);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = AllocateRaw(size, space, OLD_DATA_SPACE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   reinterpret_cast<ByteArray*>(result)->set_map(byte_array_map());
   reinterpret_cast<ByteArray*>(result)->set_length(length);
   return result;
 }
 
 
 void Heap::CreateFillerObjectAt(Address addr, int size) {
   if (size == 0) return;
   HeapObject* filler = HeapObject::FromAddress(addr);
   if (size == kPointerSize) {
     filler->set_map(one_pointer_filler_map());
   } else if (size == 2 * kPointerSize) {
     filler->set_map(two_pointer_filler_map());
   } else {
     filler->set_map(byte_array_map());
     ByteArray::cast(filler)->set_length(ByteArray::LengthFor(size));
   }
 }
 
 
-Object* Heap::AllocatePixelArray(int length,
+MaybeObject* Heap::AllocatePixelArray(int length,
                                  uint8_t* external_pointer,
                                  PretenureFlag pretenure) {
   AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
-  Object* result = AllocateRaw(PixelArray::kAlignedSize, space, OLD_DATA_SPACE);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result =
+        AllocateRaw(PixelArray::kAlignedSize, space, OLD_DATA_SPACE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   reinterpret_cast<PixelArray*>(result)->set_map(pixel_array_map());
   reinterpret_cast<PixelArray*>(result)->set_length(length);
   reinterpret_cast<PixelArray*>(result)->set_external_pointer(external_pointer);
 
   return result;
 }
 
 
-Object* Heap::AllocateExternalArray(int length,
-                                    ExternalArrayType array_type,
-                                    void* external_pointer,
-                                    PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateExternalArray(int length,
+                                         ExternalArrayType array_type,
+                                         void* external_pointer,
+                                         PretenureFlag pretenure) {
   AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
-  Object* result = AllocateRaw(ExternalArray::kAlignedSize,
-                               space,
-                               OLD_DATA_SPACE);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = AllocateRaw(ExternalArray::kAlignedSize,
+                                            space,
+                                            OLD_DATA_SPACE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   reinterpret_cast<ExternalArray*>(result)->set_map(
       MapForExternalArrayType(array_type));
   reinterpret_cast<ExternalArray*>(result)->set_length(length);
   reinterpret_cast<ExternalArray*>(result)->set_external_pointer(
       external_pointer);
 
   return result;
 }
 
 
-Object* Heap::CreateCode(const CodeDesc& desc,
-                         Code::Flags flags,
-                         Handle<Object> self_reference) {
+MaybeObject* Heap::CreateCode(const CodeDesc& desc,
+                              Code::Flags flags,
+                              Handle<Object> self_reference) {
   // Allocate ByteArray before the Code object, so that we do not risk
   // leaving uninitialized Code object (and breaking the heap).
-  Object* reloc_info = AllocateByteArray(desc.reloc_size, TENURED);
-  if (reloc_info->IsFailure()) return reloc_info;
+  Object* reloc_info;
+  { MaybeObject* maybe_reloc_info = AllocateByteArray(desc.reloc_size, TENURED);
+    if (!maybe_reloc_info->ToObject(&reloc_info)) return maybe_reloc_info;
+  }
 
   // Compute size
   int body_size = RoundUp(desc.instr_size, kObjectAlignment);
   int obj_size = Code::SizeFor(body_size);
   ASSERT(IsAligned(static_cast<intptr_t>(obj_size), kCodeAlignment));
-  Object* result;
+  MaybeObject* maybe_result;
   if (obj_size > MaxObjectSizeInPagedSpace()) {
-    result = lo_space_->AllocateRawCode(obj_size);
+    maybe_result = lo_space_->AllocateRawCode(obj_size);
   } else {
-    result = code_space_->AllocateRaw(obj_size);
+    maybe_result = code_space_->AllocateRaw(obj_size);
   }
 
-  if (result->IsFailure()) return result;
+  Object* result;
+  if (!maybe_result->ToObject(&result)) return maybe_result;
 
   // Initialize the object
   HeapObject::cast(result)->set_map(code_map());
   Code* code = Code::cast(result);
   ASSERT(!CodeRange::exists() || CodeRange::contains(code->address()));
   code->set_instruction_size(desc.instr_size);
   code->set_relocation_info(ByteArray::cast(reloc_info));
   code->set_flags(flags);
   // Allow self references to created code object by patching the handle to
   // point to the newly allocated Code object.
   if (!self_reference.is_null()) {
     *(self_reference.location()) = code;
   }
   // Migrate generated code.
   // The generated code can contain Object** values (typically from handles)
   // that are dereferenced during the copy to point directly to the actual heap
   // objects. These pointers can include references to the code object itself,
   // through the self_reference parameter.
   code->CopyFrom(desc);
 
 #ifdef DEBUG
   code->Verify();
 #endif
   return code;
 }
 
 
-Object* Heap::CopyCode(Code* code) {
+MaybeObject* Heap::CopyCode(Code* code) {
   // Allocate an object the same size as the code object.
   int obj_size = code->Size();
-  Object* result;
+  MaybeObject* maybe_result;
   if (obj_size > MaxObjectSizeInPagedSpace()) {
-    result = lo_space_->AllocateRawCode(obj_size);
+    maybe_result = lo_space_->AllocateRawCode(obj_size);
   } else {
-    result = code_space_->AllocateRaw(obj_size);
+    maybe_result = code_space_->AllocateRaw(obj_size);
   }
 
-  if (result->IsFailure()) return result;
+  Object* result;
+  if (!maybe_result->ToObject(&result)) return maybe_result;
 
   // Copy code object.
   Address old_addr = code->address();
   Address new_addr = reinterpret_cast<HeapObject*>(result)->address();
   CopyBlock(new_addr, old_addr, obj_size);
   // Relocate the copy.
   Code* new_code = Code::cast(result);
   ASSERT(!CodeRange::exists() || CodeRange::contains(code->address()));
   new_code->Relocate(new_addr - old_addr);
   return new_code;
 }
 
 
-Object* Heap::CopyCode(Code* code, Vector<byte> reloc_info) {
+MaybeObject* Heap::CopyCode(Code* code, Vector<byte> reloc_info) {
   // Allocate ByteArray before the Code object, so that we do not risk
   // leaving uninitialized Code object (and breaking the heap).
-  Object* reloc_info_array = AllocateByteArray(reloc_info.length(), TENURED);
-  if (reloc_info_array->IsFailure()) return reloc_info_array;
+  Object* reloc_info_array;
+  { MaybeObject* maybe_reloc_info_array =
+        AllocateByteArray(reloc_info.length(), TENURED);
+    if (!maybe_reloc_info_array->ToObject(&reloc_info_array)) {
+      return maybe_reloc_info_array;
+    }
+  }
 
   int new_body_size = RoundUp(code->instruction_size(), kObjectAlignment);
 
   int new_obj_size = Code::SizeFor(new_body_size);
 
   Address old_addr = code->address();
 
   size_t relocation_offset =
       static_cast<size_t>(code->instruction_end() - old_addr);
 
-  Object* result;
+  MaybeObject* maybe_result;
   if (new_obj_size > MaxObjectSizeInPagedSpace()) {
-    result = lo_space_->AllocateRawCode(new_obj_size);
+    maybe_result = lo_space_->AllocateRawCode(new_obj_size);
   } else {
-    result = code_space_->AllocateRaw(new_obj_size);
+    maybe_result = code_space_->AllocateRaw(new_obj_size);
   }
 
-  if (result->IsFailure()) return result;
+  Object* result;
+  if (!maybe_result->ToObject(&result)) return maybe_result;
 
   // Copy code object.
   Address new_addr = reinterpret_cast<HeapObject*>(result)->address();
 
   // Copy header and instructions.
   memcpy(new_addr, old_addr, relocation_offset);
 
   Code* new_code = Code::cast(result);
   new_code->set_relocation_info(ByteArray::cast(reloc_info_array));
 
   // Copy patched rinfo.
   memcpy(new_code->relocation_start(), reloc_info.start(), reloc_info.length());
 
   // Relocate the copy.
   ASSERT(!CodeRange::exists() || CodeRange::contains(code->address()));
   new_code->Relocate(new_addr - old_addr);
 
 #ifdef DEBUG
   code->Verify();
 #endif
   return new_code;
 }
 
 
-Object* Heap::Allocate(Map* map, AllocationSpace space) {
+MaybeObject* Heap::Allocate(Map* map, AllocationSpace space) {
   ASSERT(gc_state_ == NOT_IN_GC);
   ASSERT(map->instance_type() != MAP_TYPE);
   // If allocation failures are disallowed, we may allocate in a different
   // space when new space is full and the object is not a large object.
   AllocationSpace retry_space =
       (space != NEW_SPACE) ? space : TargetSpaceId(map->instance_type());
-  Object* result =
-      AllocateRaw(map->instance_size(), space, retry_space);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result =
+        AllocateRaw(map->instance_size(), space, retry_space);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   HeapObject::cast(result)->set_map(map);
 #ifdef ENABLE_LOGGING_AND_PROFILING
   ProducerHeapProfile::RecordJSObjectAllocation(result);
 #endif
   return result;
 }
 
 
-Object* Heap::InitializeFunction(JSFunction* function,
-                                 SharedFunctionInfo* shared,
-                                 Object* prototype) {
+MaybeObject* Heap::InitializeFunction(JSFunction* function,
+                                      SharedFunctionInfo* shared,
+                                      Object* prototype) {
   ASSERT(!prototype->IsMap());
   function->initialize_properties();
   function->initialize_elements();
   function->set_shared(shared);
   function->set_code(shared->code());
   function->set_prototype_or_initial_map(prototype);
   function->set_context(undefined_value());
   function->set_literals(empty_fixed_array());
   return function;
 }
 
 
-Object* Heap::AllocateFunctionPrototype(JSFunction* function) {
+MaybeObject* Heap::AllocateFunctionPrototype(JSFunction* function) {
   // Allocate the prototype.  Make sure to use the object function
   // from the function's context, since the function can be from a
   // different context.
   JSFunction* object_function =
       function->context()->global_context()->object_function();
-  Object* prototype = AllocateJSObject(object_function);
-  if (prototype->IsFailure()) return prototype;
+  Object* prototype;
+  { MaybeObject* maybe_prototype = AllocateJSObject(object_function);
+    if (!maybe_prototype->ToObject(&prototype)) return maybe_prototype;
+  }
   // When creating the prototype for the function we must set its
   // constructor to the function.
-  Object* result =
-      JSObject::cast(prototype)->SetProperty(constructor_symbol(),
-                                             function,
-                                             DONT_ENUM);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result =
+        JSObject::cast(prototype)->SetProperty(constructor_symbol(),
+                                               function,
+                                               DONT_ENUM);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   return prototype;
 }
 
 
-Object* Heap::AllocateFunction(Map* function_map,
-                               SharedFunctionInfo* shared,
-                               Object* prototype,
-                               PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateFunction(Map* function_map,
+                                    SharedFunctionInfo* shared,
+                                    Object* prototype,
+                                    PretenureFlag pretenure) {
   AllocationSpace space =
       (pretenure == TENURED) ? OLD_POINTER_SPACE : NEW_SPACE;
-  Object* result = Allocate(function_map, space);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = Allocate(function_map, space);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   return InitializeFunction(JSFunction::cast(result), shared, prototype);
 }
 
 
-Object* Heap::AllocateArgumentsObject(Object* callee, int length) {
+MaybeObject* Heap::AllocateArgumentsObject(Object* callee, int length) {
   // To get fast allocation and map sharing for arguments objects we
   // allocate them based on an arguments boilerplate.
 
   // This calls Copy directly rather than using Heap::AllocateRaw so we
   // duplicate the check here.
   ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
 
   JSObject* boilerplate =
       Top::context()->global_context()->arguments_boilerplate();
 
   // Check that the size of the boilerplate matches our
   // expectations. The ArgumentsAccessStub::GenerateNewObject relies
   // on the size being a known constant.
   ASSERT(kArgumentsObjectSize == boilerplate->map()->instance_size());
 
   // Do the allocation.
-  Object* result =
-      AllocateRaw(kArgumentsObjectSize, NEW_SPACE, OLD_POINTER_SPACE);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result =
+        AllocateRaw(kArgumentsObjectSize, NEW_SPACE, OLD_POINTER_SPACE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   // Copy the content. The arguments boilerplate doesn't have any
   // fields that point to new space so it's safe to skip the write
   // barrier here.
   CopyBlock(HeapObject::cast(result)->address(),
             boilerplate->address(),
             kArgumentsObjectSize);
 
   // Set the two properties.
   JSObject::cast(result)->InObjectPropertyAtPut(arguments_callee_index,
@@ skipping 17 matching lines @@
     for (int i = 1; i != count; i++) {
       String* current_key = descriptors->GetKey(i);
       if (prev_key == current_key) return true;
       prev_key = current_key;
     }
   }
   return false;
 }
 
 
-Object* Heap::AllocateInitialMap(JSFunction* fun) {
+MaybeObject* Heap::AllocateInitialMap(JSFunction* fun) {
   ASSERT(!fun->has_initial_map());
 
   // First create a new map with the size and number of in-object properties
   // suggested by the function.
   int instance_size = fun->shared()->CalculateInstanceSize();
   int in_object_properties = fun->shared()->CalculateInObjectProperties();
-  Object* map_obj = Heap::AllocateMap(JS_OBJECT_TYPE, instance_size);
-  if (map_obj->IsFailure()) return map_obj;
+  Object* map_obj;
+  { MaybeObject* maybe_map_obj =
+        Heap::AllocateMap(JS_OBJECT_TYPE, instance_size);
+    if (!maybe_map_obj->ToObject(&map_obj)) return maybe_map_obj;
+  }
 
   // Fetch or allocate prototype.
   Object* prototype;
   if (fun->has_instance_prototype()) {
     prototype = fun->instance_prototype();
   } else {
-    prototype = AllocateFunctionPrototype(fun);
-    if (prototype->IsFailure()) return prototype;
+    { MaybeObject* maybe_prototype = AllocateFunctionPrototype(fun);
+      if (!maybe_prototype->ToObject(&prototype)) return maybe_prototype;
+    }
   }
   Map* map = Map::cast(map_obj);
   map->set_inobject_properties(in_object_properties);
   map->set_unused_property_fields(in_object_properties);
   map->set_prototype(prototype);
   ASSERT(map->has_fast_elements());
 
   // If the function has only simple this property assignments add
   // field descriptors for these to the initial map as the object
   // cannot be constructed without having these properties.  Guard by
   // the inline_new flag so we only change the map if we generate a
   // specialized construct stub.
   ASSERT(in_object_properties <= Map::kMaxPreAllocatedPropertyFields);
   if (fun->shared()->CanGenerateInlineConstructor(prototype)) {
     int count = fun->shared()->this_property_assignments_count();
     if (count > in_object_properties) {
       // Inline constructor can only handle inobject properties.
       fun->shared()->ForbidInlineConstructor();
     } else {
-      Object* descriptors_obj = DescriptorArray::Allocate(count);
-      if (descriptors_obj->IsFailure()) return descriptors_obj;
+      Object* descriptors_obj;
+      { MaybeObject* maybe_descriptors_obj = DescriptorArray::Allocate(count);
+        if (!maybe_descriptors_obj->ToObject(&descriptors_obj)) {
+          return maybe_descriptors_obj;
+        }
+      }
       DescriptorArray* descriptors = DescriptorArray::cast(descriptors_obj);
       for (int i = 0; i < count; i++) {
         String* name = fun->shared()->GetThisPropertyAssignmentName(i);
         ASSERT(name->IsSymbol());
         FieldDescriptor field(name, i, NONE);
         field.SetEnumerationIndex(i);
         descriptors->Set(i, &field);
       }
       descriptors->SetNextEnumerationIndex(count);
       descriptors->SortUnchecked();
@@ skipping 40 matching lines @@
     // We might want to shrink the object later.
     ASSERT(obj->GetInternalFieldCount() == 0);
     filler = Heap::one_pointer_filler_map();
   } else {
     filler = Heap::undefined_value();
   }
   obj->InitializeBody(map->instance_size(), filler);
 }
 
 
-Object* Heap::AllocateJSObjectFromMap(Map* map, PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateJSObjectFromMap(Map* map, PretenureFlag pretenure) {
   // JSFunctions should be allocated using AllocateFunction to be
   // properly initialized.
   ASSERT(map->instance_type() != JS_FUNCTION_TYPE);
 
   // Both types of global objects should be allocated using
   // AllocateGlobalObject to be properly initialized.
   ASSERT(map->instance_type() != JS_GLOBAL_OBJECT_TYPE);
   ASSERT(map->instance_type() != JS_BUILTINS_OBJECT_TYPE);
 
   // Allocate the backing storage for the properties.
   int prop_size =
       map->pre_allocated_property_fields() +
       map->unused_property_fields() -
       map->inobject_properties();
   ASSERT(prop_size >= 0);
-  Object* properties = AllocateFixedArray(prop_size, pretenure);
-  if (properties->IsFailure()) return properties;
+  Object* properties;
+  { MaybeObject* maybe_properties = AllocateFixedArray(prop_size, pretenure);
+    if (!maybe_properties->ToObject(&properties)) return maybe_properties;
+  }
 
   // Allocate the JSObject.
   AllocationSpace space =
       (pretenure == TENURED) ? OLD_POINTER_SPACE : NEW_SPACE;
   if (map->instance_size() > MaxObjectSizeInPagedSpace()) space = LO_SPACE;
-  Object* obj = Allocate(map, space);
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = Allocate(map, space);
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   // Initialize the JSObject.
   InitializeJSObjectFromMap(JSObject::cast(obj),
                             FixedArray::cast(properties),
                             map);
   ASSERT(JSObject::cast(obj)->HasFastElements());
   return obj;
 }
 
 
-Object* Heap::AllocateJSObject(JSFunction* constructor,
-                               PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateJSObject(JSFunction* constructor,
+                                    PretenureFlag pretenure) {
   // Allocate the initial map if absent.
   if (!constructor->has_initial_map()) {
-    Object* initial_map = AllocateInitialMap(constructor);
-    if (initial_map->IsFailure()) return initial_map;
+    Object* initial_map;
+    { MaybeObject* maybe_initial_map = AllocateInitialMap(constructor);
+      if (!maybe_initial_map->ToObject(&initial_map)) return maybe_initial_map;
+    }
     constructor->set_initial_map(Map::cast(initial_map));
     Map::cast(initial_map)->set_constructor(constructor);
   }
   // Allocate the object based on the constructors initial map.
-  Object* result =
+  MaybeObject* result =
       AllocateJSObjectFromMap(constructor->initial_map(), pretenure);
+#ifdef DEBUG
   // Make sure result is NOT a global object if valid.
-  ASSERT(result->IsFailure() || !result->IsGlobalObject());
+  Object* non_failure;
+  ASSERT(!result->ToObject(&non_failure) || !non_failure->IsGlobalObject());
+#endif
   return result;
 }
 
 
-Object* Heap::AllocateGlobalObject(JSFunction* constructor) {
+MaybeObject* Heap::AllocateGlobalObject(JSFunction* constructor) {
   ASSERT(constructor->has_initial_map());
   Map* map = constructor->initial_map();
 
   // Make sure no field properties are described in the initial map.
   // This guarantees us that normalizing the properties does not
   // require us to change property values to JSGlobalPropertyCells.
   ASSERT(map->NextFreePropertyIndex() == 0);
 
   // Make sure we don't have a ton of pre-allocated slots in the
   // global objects. They will be unused once we normalize the object.
   ASSERT(map->unused_property_fields() == 0);
   ASSERT(map->inobject_properties() == 0);
 
   // Initial size of the backing store to avoid resize of the storage during
   // bootstrapping. The size differs between the JS global object ad the
   // builtins object.
   int initial_size = map->instance_type() == JS_GLOBAL_OBJECT_TYPE ? 64 : 512;
 
   // Allocate a dictionary object for backing storage.
-  Object* obj =
-      StringDictionary::Allocate(
-          map->NumberOfDescribedProperties() * 2 + initial_size);
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj =
+        StringDictionary::Allocate(
+            map->NumberOfDescribedProperties() * 2 + initial_size);
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
   StringDictionary* dictionary = StringDictionary::cast(obj);
 
   // The global object might be created from an object template with accessors.
   // Fill these accessors into the dictionary.
   DescriptorArray* descs = map->instance_descriptors();
   for (int i = 0; i < descs->number_of_descriptors(); i++) {
     PropertyDetails details = descs->GetDetails(i);
     ASSERT(details.type() == CALLBACKS);  // Only accessors are expected.
     PropertyDetails d =
         PropertyDetails(details.attributes(), CALLBACKS, details.index());
     Object* value = descs->GetCallbacksObject(i);
-    value = Heap::AllocateJSGlobalPropertyCell(value);
-    if (value->IsFailure()) return value;
+    { MaybeObject* maybe_value = Heap::AllocateJSGlobalPropertyCell(value);
+      if (!maybe_value->ToObject(&value)) return maybe_value;
+    }
 
-    Object* result = dictionary->Add(descs->GetKey(i), value, d);
-    if (result->IsFailure()) return result;
+    Object* result;
+    { MaybeObject* maybe_result = dictionary->Add(descs->GetKey(i), value, d);
+      if (!maybe_result->ToObject(&result)) return maybe_result;
+    }
     dictionary = StringDictionary::cast(result);
   }
 
   // Allocate the global object and initialize it with the backing store.
-  obj = Allocate(map, OLD_POINTER_SPACE);
-  if (obj->IsFailure()) return obj;
+  { MaybeObject* maybe_obj = Allocate(map, OLD_POINTER_SPACE);
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
   JSObject* global = JSObject::cast(obj);
   InitializeJSObjectFromMap(global, dictionary, map);
 
   // Create a new map for the global object.
-  obj = map->CopyDropDescriptors();
-  if (obj->IsFailure()) return obj;
+  { MaybeObject* maybe_obj = map->CopyDropDescriptors();
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
   Map* new_map = Map::cast(obj);
 
   // Setup the global object as a normalized object.
   global->set_map(new_map);
   global->map()->set_instance_descriptors(Heap::empty_descriptor_array());
   global->set_properties(dictionary);
 
   // Make sure result is a global object with properties in dictionary.
   ASSERT(global->IsGlobalObject());
   ASSERT(!global->HasFastProperties());
   return global;
 }
 
 
-Object* Heap::CopyJSObject(JSObject* source) {
+MaybeObject* Heap::CopyJSObject(JSObject* source) {
   // Never used to copy functions.  If functions need to be copied we
   // have to be careful to clear the literals array.
   ASSERT(!source->IsJSFunction());
 
   // Make the clone.
   Map* map = source->map();
   int object_size = map->instance_size();
   Object* clone;
 
   // If we're forced to always allocate, we use the general allocation
   // functions which may leave us with an object in old space.
   if (always_allocate()) {
-    clone = AllocateRaw(object_size, NEW_SPACE, OLD_POINTER_SPACE);
-    if (clone->IsFailure()) return clone;
+    { MaybeObject* maybe_clone =
+          AllocateRaw(object_size, NEW_SPACE, OLD_POINTER_SPACE);
+      if (!maybe_clone->ToObject(&clone)) return maybe_clone;
+    }
     Address clone_address = HeapObject::cast(clone)->address();
     CopyBlock(clone_address,
               source->address(),
               object_size);
     // Update write barrier for all fields that lie beyond the header.
     RecordWrites(clone_address,
                  JSObject::kHeaderSize,
                  (object_size - JSObject::kHeaderSize) / kPointerSize);
   } else {
-    clone = new_space_.AllocateRaw(object_size);
-    if (clone->IsFailure()) return clone;
+    { MaybeObject* maybe_clone = new_space_.AllocateRaw(object_size);
+      if (!maybe_clone->ToObject(&clone)) return maybe_clone;
+    }
     ASSERT(Heap::InNewSpace(clone));
     // Since we know the clone is allocated in new space, we can copy
     // the contents without worrying about updating the write barrier.
     CopyBlock(HeapObject::cast(clone)->address(),
               source->address(),
               object_size);
   }
 
   FixedArray* elements = FixedArray::cast(source->elements());
   FixedArray* properties = FixedArray::cast(source->properties());
   // Update elements if necessary.
   if (elements->length() > 0) {
-    Object* elem =
-        (elements->map() == fixed_cow_array_map()) ?
-        elements : CopyFixedArray(elements);
-    if (elem->IsFailure()) return elem;
+    Object* elem;
+    { MaybeObject* maybe_elem =
+          (elements->map() == fixed_cow_array_map()) ?
+          elements : CopyFixedArray(elements);
+      if (!maybe_elem->ToObject(&elem)) return maybe_elem;
+    }
     JSObject::cast(clone)->set_elements(FixedArray::cast(elem));
   }
   // Update properties if necessary.
   if (properties->length() > 0) {
-    Object* prop = CopyFixedArray(properties);
-    if (prop->IsFailure()) return prop;
+    Object* prop;
+    { MaybeObject* maybe_prop = CopyFixedArray(properties);
+      if (!maybe_prop->ToObject(&prop)) return maybe_prop;
+    }
     JSObject::cast(clone)->set_properties(FixedArray::cast(prop));
   }
   // Return the new clone.
 #ifdef ENABLE_LOGGING_AND_PROFILING
   ProducerHeapProfile::RecordJSObjectAllocation(clone);
 #endif
   return clone;
 }
 
 
-Object* Heap::ReinitializeJSGlobalProxy(JSFunction* constructor,
-                                        JSGlobalProxy* object) {
+MaybeObject* Heap::ReinitializeJSGlobalProxy(JSFunction* constructor,
+                                             JSGlobalProxy* object) {
   ASSERT(constructor->has_initial_map());
   Map* map = constructor->initial_map();
 
   // Check that the already allocated object has the same size and type as
   // objects allocated using the constructor.
   ASSERT(map->instance_size() == object->map()->instance_size());
   ASSERT(map->instance_type() == object->map()->instance_type());
 
   // Allocate the backing storage for the properties.
   int prop_size = map->unused_property_fields() - map->inobject_properties();
-  Object* properties = AllocateFixedArray(prop_size, TENURED);
-  if (properties->IsFailure()) return properties;
+  Object* properties;
+  { MaybeObject* maybe_properties = AllocateFixedArray(prop_size, TENURED);
+    if (!maybe_properties->ToObject(&properties)) return maybe_properties;
+  }
 
   // Reset the map for the object.
   object->set_map(constructor->initial_map());
 
   // Reinitialize the object from the constructor map.
   InitializeJSObjectFromMap(object, FixedArray::cast(properties), map);
   return object;
 }
 
 
-Object* Heap::AllocateStringFromAscii(Vector<const char> string,
-                                      PretenureFlag pretenure) {
-  Object* result = AllocateRawAsciiString(string.length(), pretenure);
-  if (result->IsFailure()) return result;
+MaybeObject* Heap::AllocateStringFromAscii(Vector<const char> string,
+                                           PretenureFlag pretenure) {
+  Object* result;
+  { MaybeObject* maybe_result =
+        AllocateRawAsciiString(string.length(), pretenure);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   // Copy the characters into the new object.
   SeqAsciiString* string_result = SeqAsciiString::cast(result);
   for (int i = 0; i < string.length(); i++) {
     string_result->SeqAsciiStringSet(i, string[i]);
   }
   return result;
 }
 
 
-Object* Heap::AllocateStringFromUtf8(Vector<const char> string,
-                                     PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateStringFromUtf8(Vector<const char> string,
+                                          PretenureFlag pretenure) {
   // V8 only supports characters in the Basic Multilingual Plane.
   const uc32 kMaxSupportedChar = 0xFFFF;
   // Count the number of characters in the UTF-8 string and check if
   // it is an ASCII string.
   Access<Scanner::Utf8Decoder> decoder(Scanner::utf8_decoder());
   decoder->Reset(string.start(), string.length());
   int chars = 0;
   bool is_ascii = true;
   while (decoder->has_more()) {
     uc32 r = decoder->GetNext();
     if (r > String::kMaxAsciiCharCode) is_ascii = false;
     chars++;
   }
 
   // If the string is ascii, we do not need to convert the characters
   // since UTF8 is backwards compatible with ascii.
   if (is_ascii) return AllocateStringFromAscii(string, pretenure);
 
-  Object* result = AllocateRawTwoByteString(chars, pretenure);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = AllocateRawTwoByteString(chars, pretenure);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   // Convert and copy the characters into the new object.
   String* string_result = String::cast(result);
   decoder->Reset(string.start(), string.length());
   for (int i = 0; i < chars; i++) {
     uc32 r = decoder->GetNext();
     if (r > kMaxSupportedChar) { r = unibrow::Utf8::kBadChar; }
     string_result->Set(i, r);
   }
   return result;
 }
 
 
-Object* Heap::AllocateStringFromTwoByte(Vector<const uc16> string,
-                                        PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateStringFromTwoByte(Vector<const uc16> string,
+                                             PretenureFlag pretenure) {
   // Check if the string is an ASCII string.
   int i = 0;
   while (i < string.length() && string[i] <= String::kMaxAsciiCharCode) i++;
 
+  MaybeObject* maybe_result;
+  if (i == string.length()) {  // It's an ASCII string.
+    maybe_result = AllocateRawAsciiString(string.length(), pretenure);
+  } else {  // It's not an ASCII string.
+    maybe_result = AllocateRawTwoByteString(string.length(), pretenure);
+  }
   Object* result;
-  if (i == string.length()) {  // It's an ASCII string.
-    result = AllocateRawAsciiString(string.length(), pretenure);
-  } else {  // It's not an ASCII string.
-    result = AllocateRawTwoByteString(string.length(), pretenure);
-  }
-  if (result->IsFailure()) return result;
+  if (!maybe_result->ToObject(&result)) return maybe_result;
 
   // Copy the characters into the new object, which may be either ASCII or
   // UTF-16.
   String* string_result = String::cast(result);
   for (int i = 0; i < string.length(); i++) {
     string_result->Set(i, string[i]);
   }
   return result;
 }
 
@@ skipping 12 matching lines @@
   if (map == external_ascii_string_map()) return external_ascii_symbol_map();
   if (map == external_string_with_ascii_data_map()) {
     return external_symbol_with_ascii_data_map();
   }
 
   // No match found.
   return NULL;
 }
 
 
-Object* Heap::AllocateInternalSymbol(unibrow::CharacterStream* buffer,
-                                     int chars,
-                                     uint32_t hash_field) {
+MaybeObject* Heap::AllocateInternalSymbol(unibrow::CharacterStream* buffer,
+                                          int chars,
+                                          uint32_t hash_field) {
   ASSERT(chars >= 0);
   // Ensure the chars matches the number of characters in the buffer.
   ASSERT(static_cast<unsigned>(chars) == buffer->Length());
   // Determine whether the string is ascii.
   bool is_ascii = true;
   while (buffer->has_more()) {
     if (buffer->GetNext() > unibrow::Utf8::kMaxOneByteChar) {
       is_ascii = false;
       break;
     }
@@ skipping 12 matching lines @@
     size = SeqAsciiString::SizeFor(chars);
   } else {
     if (chars > SeqTwoByteString::kMaxLength) {
       return Failure::OutOfMemoryException();
     }
     map = symbol_map();
     size = SeqTwoByteString::SizeFor(chars);
   }
 
   // Allocate string.
-  Object* result = (size > MaxObjectSizeInPagedSpace())
-      ? lo_space_->AllocateRaw(size)
-      : old_data_space_->AllocateRaw(size);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = (size > MaxObjectSizeInPagedSpace())
+                   ? lo_space_->AllocateRaw(size)
+                   : old_data_space_->AllocateRaw(size);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   reinterpret_cast<HeapObject*>(result)->set_map(map);
   // Set length and hash fields of the allocated string.
   String* answer = String::cast(result);
   answer->set_length(chars);
   answer->set_hash_field(hash_field);
 
   ASSERT_EQ(size, answer->Size());
 
   // Fill in the characters.
   for (int i = 0; i < chars; i++) {
     answer->Set(i, buffer->GetNext());
   }
   return answer;
 }
 
 
-Object* Heap::AllocateRawAsciiString(int length, PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateRawAsciiString(int length, PretenureFlag pretenure) {
   if (length < 0 || length > SeqAsciiString::kMaxLength) {
     return Failure::OutOfMemoryException();
   }
 
   int size = SeqAsciiString::SizeFor(length);
   ASSERT(size <= SeqAsciiString::kMaxSize);
 
   AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
   AllocationSpace retry_space = OLD_DATA_SPACE;
 
   if (space == NEW_SPACE) {
     if (size > kMaxObjectSizeInNewSpace) {
       // Allocate in large object space, retry space will be ignored.
       space = LO_SPACE;
     } else if (size > MaxObjectSizeInPagedSpace()) {
       // Allocate in new space, retry in large object space.
       retry_space = LO_SPACE;
     }
   } else if (space == OLD_DATA_SPACE && size > MaxObjectSizeInPagedSpace()) {
     space = LO_SPACE;
   }
-  Object* result = AllocateRaw(size, space, retry_space);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = AllocateRaw(size, space, retry_space);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   // Partially initialize the object.
   HeapObject::cast(result)->set_map(ascii_string_map());
   String::cast(result)->set_length(length);
   String::cast(result)->set_hash_field(String::kEmptyHashField);
   ASSERT_EQ(size, HeapObject::cast(result)->Size());
   return result;
 }
 
 
-Object* Heap::AllocateRawTwoByteString(int length, PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateRawTwoByteString(int length,
+                                            PretenureFlag pretenure) {
   if (length < 0 || length > SeqTwoByteString::kMaxLength) {
     return Failure::OutOfMemoryException();
   }
   int size = SeqTwoByteString::SizeFor(length);
   ASSERT(size <= SeqTwoByteString::kMaxSize);
   AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
   AllocationSpace retry_space = OLD_DATA_SPACE;
 
   if (space == NEW_SPACE) {
     if (size > kMaxObjectSizeInNewSpace) {
       // Allocate in large object space, retry space will be ignored.
       space = LO_SPACE;
     } else if (size > MaxObjectSizeInPagedSpace()) {
       // Allocate in new space, retry in large object space.
       retry_space = LO_SPACE;
     }
   } else if (space == OLD_DATA_SPACE && size > MaxObjectSizeInPagedSpace()) {
     space = LO_SPACE;
   }
-  Object* result = AllocateRaw(size, space, retry_space);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = AllocateRaw(size, space, retry_space);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   // Partially initialize the object.
   HeapObject::cast(result)->set_map(string_map());
   String::cast(result)->set_length(length);
   String::cast(result)->set_hash_field(String::kEmptyHashField);
   ASSERT_EQ(size, HeapObject::cast(result)->Size());
   return result;
 }
 
 
-Object* Heap::AllocateEmptyFixedArray() {
+MaybeObject* Heap::AllocateEmptyFixedArray() {
   int size = FixedArray::SizeFor(0);
-  Object* result = AllocateRaw(size, OLD_DATA_SPACE, OLD_DATA_SPACE);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result =
+        AllocateRaw(size, OLD_DATA_SPACE, OLD_DATA_SPACE);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   // Initialize the object.
   reinterpret_cast<FixedArray*>(result)->set_map(fixed_array_map());
   reinterpret_cast<FixedArray*>(result)->set_length(0);
   return result;
 }
 
 
-Object* Heap::AllocateRawFixedArray(int length) {
+MaybeObject* Heap::AllocateRawFixedArray(int length) {
   if (length < 0 || length > FixedArray::kMaxLength) {
     return Failure::OutOfMemoryException();
   }
   ASSERT(length > 0);
   // Use the general function if we're forced to always allocate.
   if (always_allocate()) return AllocateFixedArray(length, TENURED);
   // Allocate the raw data for a fixed array.
   int size = FixedArray::SizeFor(length);
   return size <= kMaxObjectSizeInNewSpace
       ? new_space_.AllocateRaw(size)
       : lo_space_->AllocateRawFixedArray(size);
 }
 
 
-Object* Heap::CopyFixedArrayWithMap(FixedArray* src, Map* map) {
+MaybeObject* Heap::CopyFixedArrayWithMap(FixedArray* src, Map* map) {
   int len = src->length();
-  Object* obj = AllocateRawFixedArray(len);
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = AllocateRawFixedArray(len);
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
   if (Heap::InNewSpace(obj)) {
     HeapObject* dst = HeapObject::cast(obj);
     dst->set_map(map);
     CopyBlock(dst->address() + kPointerSize,
               src->address() + kPointerSize,
               FixedArray::SizeFor(len) - kPointerSize);
     return obj;
   }
   HeapObject::cast(obj)->set_map(map);
   FixedArray* result = FixedArray::cast(obj);
   result->set_length(len);
 
   // Copy the content
   AssertNoAllocation no_gc;
   WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);
   for (int i = 0; i < len; i++) result->set(i, src->get(i), mode);
   return result;
 }
 
 
-Object* Heap::AllocateFixedArray(int length) {
+MaybeObject* Heap::AllocateFixedArray(int length) {
   ASSERT(length >= 0);
   if (length == 0) return empty_fixed_array();
-  Object* result = AllocateRawFixedArray(length);
-  if (!result->IsFailure()) {
-    // Initialize header.
-    FixedArray* array = reinterpret_cast<FixedArray*>(result);
-    array->set_map(fixed_array_map());
-    array->set_length(length);
-    // Initialize body.
-    ASSERT(!Heap::InNewSpace(undefined_value()));
-    MemsetPointer(array->data_start(), undefined_value(), length);
+  Object* result;
+  { MaybeObject* maybe_result = AllocateRawFixedArray(length);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
   }
+  // Initialize header.
+  FixedArray* array = reinterpret_cast<FixedArray*>(result);
+  array->set_map(fixed_array_map());
+  array->set_length(length);
+  // Initialize body.
+  ASSERT(!Heap::InNewSpace(undefined_value()));
+  MemsetPointer(array->data_start(), undefined_value(), length);
   return result;
 }
 
 
-Object* Heap::AllocateRawFixedArray(int length, PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateRawFixedArray(int length, PretenureFlag pretenure) {
   if (length < 0 || length > FixedArray::kMaxLength) {
     return Failure::OutOfMemoryException();
   }
 
   AllocationSpace space =
       (pretenure == TENURED) ? OLD_POINTER_SPACE : NEW_SPACE;
   int size = FixedArray::SizeFor(length);
   if (space == NEW_SPACE && size > kMaxObjectSizeInNewSpace) {
     // Too big for new space.
     space = LO_SPACE;
   } else if (space == OLD_POINTER_SPACE &&
              size > MaxObjectSizeInPagedSpace()) {
     // Too big for old pointer space.
     space = LO_SPACE;
   }
 
   AllocationSpace retry_space =
       (size <= MaxObjectSizeInPagedSpace()) ? OLD_POINTER_SPACE : LO_SPACE;
 
   return AllocateRaw(size, space, retry_space);
 }
 
 
-static Object* AllocateFixedArrayWithFiller(int length,
-                                            PretenureFlag pretenure,
-                                            Object* filler) {
+MUST_USE_RESULT static MaybeObject* AllocateFixedArrayWithFiller(
+    int length,
+    PretenureFlag pretenure,
+    Object* filler) {
   ASSERT(length >= 0);
   ASSERT(Heap::empty_fixed_array()->IsFixedArray());
   if (length == 0) return Heap::empty_fixed_array();
 
   ASSERT(!Heap::InNewSpace(filler));
-  Object* result = Heap::AllocateRawFixedArray(length, pretenure);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = Heap::AllocateRawFixedArray(length, pretenure);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
 
   HeapObject::cast(result)->set_map(Heap::fixed_array_map());
   FixedArray* array = FixedArray::cast(result);
   array->set_length(length);
   MemsetPointer(array->data_start(), filler, length);
   return array;
 }
 
 
-Object* Heap::AllocateFixedArray(int length, PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateFixedArray(int length, PretenureFlag pretenure) {
   return AllocateFixedArrayWithFiller(length, pretenure, undefined_value());
 }
 
 
-Object* Heap::AllocateFixedArrayWithHoles(int length, PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateFixedArrayWithHoles(int length,
+                                               PretenureFlag pretenure) {
   return AllocateFixedArrayWithFiller(length, pretenure, the_hole_value());
 }
 
 
-Object* Heap::AllocateUninitializedFixedArray(int length) {
+MaybeObject* Heap::AllocateUninitializedFixedArray(int length) {
   if (length == 0) return empty_fixed_array();
 
-  Object* obj = AllocateRawFixedArray(length);
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = AllocateRawFixedArray(length);
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   reinterpret_cast<FixedArray*>(obj)->set_map(fixed_array_map());
   FixedArray::cast(obj)->set_length(length);
   return obj;
 }
 
 
-Object* Heap::AllocateHashTable(int length, PretenureFlag pretenure) {
-  Object* result = Heap::AllocateFixedArray(length, pretenure);
-  if (result->IsFailure()) return result;
+MaybeObject* Heap::AllocateHashTable(int length, PretenureFlag pretenure) {
+  Object* result;
+  { MaybeObject* maybe_result = Heap::AllocateFixedArray(length, pretenure);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   reinterpret_cast<HeapObject*>(result)->set_map(hash_table_map());
   ASSERT(result->IsHashTable());
   return result;
 }
 
 
-Object* Heap::AllocateGlobalContext() {
-  Object* result = Heap::AllocateFixedArray(Context::GLOBAL_CONTEXT_SLOTS);
-  if (result->IsFailure()) return result;
+MaybeObject* Heap::AllocateGlobalContext() {
+  Object* result;
+  { MaybeObject* maybe_result =
+        Heap::AllocateFixedArray(Context::GLOBAL_CONTEXT_SLOTS);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   Context* context = reinterpret_cast<Context*>(result);
   context->set_map(global_context_map());
   ASSERT(context->IsGlobalContext());
   ASSERT(result->IsContext());
   return result;
 }
 
 
-Object* Heap::AllocateFunctionContext(int length, JSFunction* function) {
+MaybeObject* Heap::AllocateFunctionContext(int length, JSFunction* function) {
   ASSERT(length >= Context::MIN_CONTEXT_SLOTS);
-  Object* result = Heap::AllocateFixedArray(length);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = Heap::AllocateFixedArray(length);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   Context* context = reinterpret_cast<Context*>(result);
   context->set_map(context_map());
   context->set_closure(function);
   context->set_fcontext(context);
   context->set_previous(NULL);
   context->set_extension(NULL);
   context->set_global(function->context()->global());
   ASSERT(!context->IsGlobalContext());
   ASSERT(context->is_function_context());
   ASSERT(result->IsContext());
   return result;
 }
 
 
-Object* Heap::AllocateWithContext(Context* previous,
-                                  JSObject* extension,
-                                  bool is_catch_context) {
-  Object* result = Heap::AllocateFixedArray(Context::MIN_CONTEXT_SLOTS);
-  if (result->IsFailure()) return result;
+MaybeObject* Heap::AllocateWithContext(Context* previous,
+                                       JSObject* extension,
+                                       bool is_catch_context) {
+  Object* result;
+  { MaybeObject* maybe_result =
+        Heap::AllocateFixedArray(Context::MIN_CONTEXT_SLOTS);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   Context* context = reinterpret_cast<Context*>(result);
   context->set_map(is_catch_context ? catch_context_map() : context_map());
   context->set_closure(previous->closure());
   context->set_fcontext(previous->fcontext());
   context->set_previous(previous);
   context->set_extension(extension);
   context->set_global(previous->global());
   ASSERT(!context->IsGlobalContext());
   ASSERT(!context->is_function_context());
   ASSERT(result->IsContext());
   return result;
 }
 
 
-Object* Heap::AllocateStruct(InstanceType type) {
+MaybeObject* Heap::AllocateStruct(InstanceType type) {
   Map* map;
   switch (type) {
 #define MAKE_CASE(NAME, Name, name) case NAME##_TYPE: map = name##_map(); break;
 STRUCT_LIST(MAKE_CASE)
 #undef MAKE_CASE
     default:
       UNREACHABLE();
       return Failure::InternalError();
   }
   int size = map->instance_size();
   AllocationSpace space =
       (size > MaxObjectSizeInPagedSpace()) ? LO_SPACE : OLD_POINTER_SPACE;
-  Object* result = Heap::Allocate(map, space);
-  if (result->IsFailure()) return result;
+  Object* result;
+  { MaybeObject* maybe_result = Heap::Allocate(map, space);
+    if (!maybe_result->ToObject(&result)) return maybe_result;
+  }
   Struct::cast(result)->InitializeBody(size);
   return result;
 }
 
 
 bool Heap::IdleNotification() {
   static const int kIdlesBeforeScavenge = 4;
   static const int kIdlesBeforeMarkSweep = 7;
   static const int kIdlesBeforeMarkCompact = 8;
   static int number_idle_notifications = 0;
@@ skipping 239 matching lines @@
   VerifyPointersVisitor no_dirty_regions_visitor;
   old_data_space_->Verify(&no_dirty_regions_visitor);
   code_space_->Verify(&no_dirty_regions_visitor);
   cell_space_->Verify(&no_dirty_regions_visitor);
 
   lo_space_->Verify();
 }
 #endif  // DEBUG
 
 
-Object* Heap::LookupSymbol(Vector<const char> string) {
+MaybeObject* Heap::LookupSymbol(Vector<const char> string) {
   Object* symbol = NULL;
-  Object* new_table = symbol_table()->LookupSymbol(string, &symbol);
-  if (new_table->IsFailure()) return new_table;
+  Object* new_table;
+  { MaybeObject* maybe_new_table =
+        symbol_table()->LookupSymbol(string, &symbol);
+    if (!maybe_new_table->ToObject(&new_table)) return maybe_new_table;
+  }
   // Can't use set_symbol_table because SymbolTable::cast knows that
   // SymbolTable is a singleton and checks for identity.
   roots_[kSymbolTableRootIndex] = new_table;
   ASSERT(symbol != NULL);
   return symbol;
 }
 
 
-Object* Heap::LookupSymbol(String* string) {
+MaybeObject* Heap::LookupSymbol(String* string) {
   if (string->IsSymbol()) return string;
   Object* symbol = NULL;
-  Object* new_table = symbol_table()->LookupString(string, &symbol);
-  if (new_table->IsFailure()) return new_table;
+  Object* new_table;
+  { MaybeObject* maybe_new_table =
+        symbol_table()->LookupString(string, &symbol);
+    if (!maybe_new_table->ToObject(&new_table)) return maybe_new_table;
+  }
   // Can't use set_symbol_table because SymbolTable::cast knows that
   // SymbolTable is a singleton and checks for identity.
   roots_[kSymbolTableRootIndex] = new_table;
   ASSERT(symbol != NULL);
   return symbol;
 }
 
 
 bool Heap::LookupSymbolIfExists(String* string, String** symbol) {
   if (string->IsSymbol()) {
@@ skipping 1305 matching lines @@
 void ExternalStringTable::TearDown() {
   new_space_strings_.Free();
   old_space_strings_.Free();
 }
 
 
 List<Object*> ExternalStringTable::new_space_strings_;
 List<Object*> ExternalStringTable::old_space_strings_;
 
 } }  // namespace v8::internal