A64: Synchronize with r19234.

src/heap-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 400 matching lines @@
     // Only the latter two contain non-map-word pointers to heap objects.
     return ((type & kIsIndirectStringMask) == kIsIndirectStringTag)
         ? OLD_POINTER_SPACE
         : OLD_DATA_SPACE;
   } else {
     return (type <= LAST_DATA_TYPE) ? OLD_DATA_SPACE : OLD_POINTER_SPACE;
   }
 }
 
 
-bool Heap::AllowedToBeMigrated(HeapObject* object, AllocationSpace dst) {
+bool Heap::AllowedToBeMigrated(HeapObject* obj, AllocationSpace dst) {
   // Object migration is governed by the following rules:
   //
   // 1) Objects in new-space can be migrated to one of the old spaces
   //    that matches their target space or they stay in new-space.
   // 2) Objects in old-space stay in the same space when migrating.
   // 3) Fillers (two or more words) can migrate due to left-trimming of
   //    fixed arrays in new-space, old-data-space and old-pointer-space.
   // 4) Fillers (one word) can never migrate, they are skipped by
   //    incremental marking explicitly to prevent invalid pattern.
+  // 5) Short external strings can end up in old pointer space when a cons
+  //    string in old pointer space is made external (String::MakeExternal).
   //
   // Since this function is used for debugging only, we do not place
   // asserts here, but check everything explicitly.
-  if (object->map() == one_pointer_filler_map()) return false;
-  InstanceType type = object->map()->instance_type();
-  MemoryChunk* chunk = MemoryChunk::FromAddress(object->address());
+  if (obj->map() == one_pointer_filler_map()) return false;
+  InstanceType type = obj->map()->instance_type();
+  MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
   AllocationSpace src = chunk->owner()->identity();
   switch (src) {
     case NEW_SPACE:
       return dst == src || dst == TargetSpaceId(type);
     case OLD_POINTER_SPACE:
-      return dst == src && (dst == TargetSpaceId(type) || object->IsFiller());
+      return dst == src &&
+          (dst == TargetSpaceId(type) || obj->IsFiller() ||
+          (obj->IsExternalString() && ExternalString::cast(obj)->is_short()));
     case OLD_DATA_SPACE:
       return dst == src && dst == TargetSpaceId(type);
     case CODE_SPACE:
       return dst == src && type == CODE_TYPE;
     case MAP_SPACE:
     case CELL_SPACE:
     case PROPERTY_CELL_SPACE:
     case LO_SPACE:
       return false;
   }
@@ skipping 28 matching lines @@
 }
 
 
 void Heap::ScavengePointer(HeapObject** p) {
   ScavengeObject(p, *p);
 }
 
 
 void Heap::UpdateAllocationSiteFeedback(HeapObject* object) {
   Heap* heap = object->GetHeap();
-  ASSERT(heap->InNewSpace(object));
+  ASSERT(heap->InFromSpace(object));
 
   if (!FLAG_allocation_site_pretenuring ||
       !AllocationSite::CanTrack(object->map()->instance_type())) return;
 
-  // Either object is the last object in the from space, or there is another
-  // object of at least word size (the header map word) following it, so
-  // suffices to compare ptr and top here.
-  Address ptr = object->address() + object->Size();
-  Address top = heap->new_space()->FromSpacePageHigh();
-  ASSERT(ptr == top || ptr + HeapObject::kHeaderSize <= top);
-  if (ptr == top) return;
+  // Check if there is potentially a memento behind the object. If
+  // the last word of the momento is on another page we return
+  // immediatelly. Note that we do not have to compare with the current
+  // top pointer of the from space page, since we always install filler
+  // objects above the top pointer of a from space page when performing
+  // a garbage collection.
+  Address object_address = object->address();
+  Address memento_address = object_address + object->Size();
+  Address last_memento_word_address = memento_address + kPointerSize;
+  if (!NewSpacePage::OnSamePage(object_address,
+                                last_memento_word_address)) {
+    return;
+  }
 
-  HeapObject* candidate = HeapObject::FromAddress(ptr);
+  HeapObject* candidate = HeapObject::FromAddress(memento_address);
   if (candidate->map() != heap->allocation_memento_map()) return;
 
   AllocationMemento* memento = AllocationMemento::cast(candidate);
   if (!memento->IsValid()) return;
 
-  if (memento->GetAllocationSite()->IncrementMementoFoundCount() &&
-      heap->allocation_sites_scratchpad_length <
-      kAllocationSiteScratchpadSize) {
-    heap->allocation_sites_scratchpad[
-        heap->allocation_sites_scratchpad_length++] =
-        memento->GetAllocationSite();
+  if (memento->GetAllocationSite()->IncrementMementoFoundCount()) {
+    heap->AddAllocationSiteToScratchpad(memento->GetAllocationSite());
   }
 }
 
 
 void Heap::ScavengeObject(HeapObject** p, HeapObject* object) {
   ASSERT(object->GetIsolate()->heap()->InFromSpace(object));
 
   // We use the first word (where the map pointer usually is) of a heap
   // object to record the forwarding pointer.  A forwarding pointer can
   // point to an old space, the code space, or the to space of the new
@@ skipping 16 matching lines @@
   // Call the slow part of scavenge object.
   return ScavengeObjectSlow(p, object);
 }
 
 
 bool Heap::CollectGarbage(AllocationSpace space,
                           const char* gc_reason,
                           const v8::GCCallbackFlags callbackFlags) {
   const char* collector_reason = NULL;
   GarbageCollector collector = SelectGarbageCollector(space, &collector_reason);
-  return CollectGarbage(
-      space, collector, gc_reason, collector_reason, callbackFlags);
+  return CollectGarbage(collector, gc_reason, collector_reason, callbackFlags);
 }
 
 
 MaybeObject* Heap::PrepareForCompare(String* str) {
   // Always flatten small strings and force flattening of long strings
   // after we have accumulated a certain amount we failed to flatten.
   static const int kMaxAlwaysFlattenLength = 32;
   static const int kFlattenLongThreshold = 16*KB;
 
   const int length = str->length();
@@ skipping 269 matching lines @@
 #ifdef DEBUG
   Isolate* isolate = Isolate::Current();
   isolate->heap()->disallow_allocation_failure_ = old_state_;
 #endif
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_INL_H_