Load callback data from weak cell instead of embedding it in handler.

src/ic/x64/handler-compiler-x64.cc

 // Copyright 2014 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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/ic/call-optimization.h"
 #include "src/ic/handler-compiler.h"
@@ skipping 544 matching lines @@
   __ PopReturnAddressTo(scratch4());
 
   STATIC_ASSERT(PropertyCallbackArguments::kHolderIndex == 0);
   STATIC_ASSERT(PropertyCallbackArguments::kIsolateIndex == 1);
   STATIC_ASSERT(PropertyCallbackArguments::kReturnValueDefaultValueIndex == 2);
   STATIC_ASSERT(PropertyCallbackArguments::kReturnValueOffset == 3);
   STATIC_ASSERT(PropertyCallbackArguments::kDataIndex == 4);
   STATIC_ASSERT(PropertyCallbackArguments::kThisIndex == 5);
   STATIC_ASSERT(PropertyCallbackArguments::kArgsLength == 6);
   __ Push(receiver());  // receiver
-  if (heap()->InNewSpace(callback->data())) {
+  Handle<Object> data(callback->data(), isolate());
+  if (data->IsUndefined() || data->IsSmi()) {
+    __ Push(data);
+  } else {
     DCHECK(!scratch2().is(reg));
-    __ Move(scratch2(), callback);
-    __ Push(FieldOperand(scratch2(),
-                         ExecutableAccessorInfo::kDataOffset));  // data
-  } else {
-    __ Push(Handle<Object>(callback->data(), isolate()));
+    Handle<WeakCell> cell =
+        isolate()->factory()->NewWeakCell(Handle<HeapObject>::cast(data));
+    // The callback is alive if this instruction is executed,
+    // so the weak cell is not cleared and points to data.
+    __ GetWeakValue(scratch2(), cell);
+    __ Push(scratch2());
   }
   DCHECK(!kScratchRegister.is(reg));
   __ LoadRoot(kScratchRegister, Heap::kUndefinedValueRootIndex);
   __ Push(kScratchRegister);  // return value
   __ Push(kScratchRegister);  // return value default
   __ PushAddress(ExternalReference::isolate_address(isolate()));
   __ Push(reg);     // holder
   __ Push(name());  // name
   // Save a pointer to where we pushed the arguments pointer.  This will be
   // passed as the const PropertyAccessorInfo& to the C++ callback.
@@ skipping 176 matching lines @@
   // Return the generated code.
   return GetCode(kind(), Code::NORMAL, name);
 }
 
 
 #undef __
 }
 }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64