Reland "Only use FreeSpace objects in the free list"

src/objects-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 3316 matching lines @@
 CAST_ACCESSOR(ExternalTwoByteString)
 CAST_ACCESSOR(ExternalUint16Array)
 CAST_ACCESSOR(ExternalUint32Array)
 CAST_ACCESSOR(ExternalUint8Array)
 CAST_ACCESSOR(ExternalUint8ClampedArray)
 CAST_ACCESSOR(FixedArray)
 CAST_ACCESSOR(FixedArrayBase)
 CAST_ACCESSOR(FixedDoubleArray)
 CAST_ACCESSOR(FixedTypedArrayBase)
 CAST_ACCESSOR(Foreign)
-CAST_ACCESSOR(FreeSpace)
 CAST_ACCESSOR(GlobalObject)
 CAST_ACCESSOR(HeapObject)
 CAST_ACCESSOR(JSArray)
 CAST_ACCESSOR(JSArrayBuffer)
 CAST_ACCESSOR(JSArrayBufferView)
 CAST_ACCESSOR(JSBuiltinsObject)
 CAST_ACCESSOR(JSDataView)
 CAST_ACCESSOR(JSDate)
 CAST_ACCESSOR(JSFunction)
 CAST_ACCESSOR(JSFunctionProxy)
@@ skipping 88 matching lines @@
 SMI_ACCESSORS(FixedArrayBase, length, kLengthOffset)
 SYNCHRONIZED_SMI_ACCESSORS(FixedArrayBase, length, kLengthOffset)
 
 SMI_ACCESSORS(FreeSpace, size, kSizeOffset)
 NOBARRIER_SMI_ACCESSORS(FreeSpace, size, kSizeOffset)
 
 SMI_ACCESSORS(String, length, kLengthOffset)
 SYNCHRONIZED_SMI_ACCESSORS(String, length, kLengthOffset)
 
 
+FreeSpace* FreeSpace::next() {
+  DCHECK(map() == GetHeap()->raw_unchecked_free_space_map() ||
+         (!GetHeap()->deserialization_complete() && map() == NULL));
+  DCHECK_LE(kNextOffset + kPointerSize, nobarrier_size());
+  return reinterpret_cast<FreeSpace*>(
+      Memory::Address_at(address() + kNextOffset));
+}
+
+
+FreeSpace** FreeSpace::next_address() {
+  DCHECK(map() == GetHeap()->raw_unchecked_free_space_map() ||
+         (!GetHeap()->deserialization_complete() && map() == NULL));
+  DCHECK_LE(kNextOffset + kPointerSize, nobarrier_size());
+  return reinterpret_cast<FreeSpace**>(address() + kNextOffset);
+}
+
+
+void FreeSpace::set_next(FreeSpace* next) {
+  DCHECK(map() == GetHeap()->raw_unchecked_free_space_map() ||
+         (!GetHeap()->deserialization_complete() && map() == NULL));
+  DCHECK_LE(kNextOffset + kPointerSize, nobarrier_size());
+  base::NoBarrier_Store(
+      reinterpret_cast<base::AtomicWord*>(address() + kNextOffset),
+      reinterpret_cast<base::AtomicWord>(next));
+}
+
+
+FreeSpace* FreeSpace::cast(HeapObject* o) {
+  SLOW_DCHECK(!o->GetHeap()->deserialization_complete() || o->IsFreeSpace());
+  return reinterpret_cast<FreeSpace*>(o);
+}
+
+
 uint32_t Name::hash_field() {
   return READ_UINT32_FIELD(this, kHashFieldOffset);
 }
 
 
 void Name::set_hash_field(uint32_t value) {
   WRITE_UINT32_FIELD(this, kHashFieldOffset, value);
 #if V8_HOST_ARCH_64_BIT
 #if V8_TARGET_LITTLE_ENDIAN
   WRITE_UINT32_FIELD(this, kHashFieldSlot + kIntSize, 0);
@@ skipping 4062 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_