Embed store callback in handler via weak cell.

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 658 matching lines @@
   __ PushReturnAddressFrom(scratch2());
 
   ExternalReference ref = ExternalReference(
       IC_Utility(IC::kLoadPropertyWithInterceptor), isolate());
   __ TailCallExternalReference(
       ref, NamedLoadHandlerCompiler::kInterceptorArgsLength, 1);
 }
 
 
 Handle<Code> NamedStoreHandlerCompiler::CompileStoreCallback(
-    Handle<JSObject> object, Handle<Name> name, int accessor_index) {
+    Handle<JSObject> object, Handle<Name> name,
+    Handle<ExecutableAccessorInfo> callback) {
   Register holder_reg = Frontend(name);
 
   __ PopReturnAddressTo(scratch1());
   __ Push(receiver());
   __ Push(holder_reg);
-  __ Push(Smi::FromInt(accessor_index));
+  // If the callback cannot leak, then push the callback directly,
+  // otherwise wrap it in a weak cell.
+  if (callback->data()->IsUndefined() || callback->data()->IsSmi()) {
+    __ Push(callback);
+  } else {
+    Handle<WeakCell> cell = isolate()->factory()->NewWeakCell(callback);
+    __ Push(cell);
+  }
   __ Push(name);
   __ Push(value());
   __ PushReturnAddressFrom(scratch1());
 
   // Do tail-call to the runtime system.
   ExternalReference store_callback_property =
       ExternalReference(IC_Utility(IC::kStoreCallbackProperty), isolate());
   __ TailCallExternalReference(store_callback_property, 5, 1);
 
   // Return the generated code.
@@ skipping 59 matching lines @@
   // Return the generated code.
   return GetCode(kind(), Code::NORMAL, name);
 }
 
 
 #undef __
 }
 }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64