Refactoring PropertyCallbackInfo & FunctionCallbackInfo, step 1.

src/stub-cache.cc

Index: src/stub-cache.cc
diff --git a/src/stub-cache.cc b/src/stub-cache.cc
index f83a7d2a88f6eabbc472f65e6471416a01a5bbac..f3dbd64f147045e5a06b33f769c13d7f7b183179 100644
--- a/src/stub-cache.cc
+++ b/src/stub-cache.cc
@@ -1278,10 +1278,14 @@ RUNTIME_FUNCTION(MaybeObject*, LoadPropertyWithInterceptorOnly) {
       FUNCTION_CAST<v8::NamedPropertyGetterCallback>(getter_address);
   ASSERT(getter != NULL);
 
-  Handle<JSObject> receiver =
-      args.at<JSObject>(kArgsOffset - PCA::kThisIndex);
-  Handle<JSObject> holder =
-      args.at<JSObject>(kArgsOffset - PCA::kHolderIndex);
+  int this_index = kArgsOffset - PCA::kThisIndex;
+  int holder_index = kArgsOffset - PCA::kHolderIndex;
+  if (PCA::kThisIndex < PCA::kReturnValueOffset)

[Michael Starzinger, 2013/09/11 09:55:19]

Instead of overlaying the indices used for the arguments object here with PCA,
we should just use a separate set of constant that describes the layout.
Decouples those two things and avoids this magic "minus 2" computation. I would
put the index constant into stub-cache.h either at the top-level or into the
StubCompiler class.

[marja, 2013/09/11 16:35:32]

Done.

+      this_index -= 2;
+  if (PCA::kHolderIndex < PCA::kReturnValueOffset)
+      holder_index -= 2;
+  Handle<JSObject> receiver = args.at<JSObject>(this_index);
+  Handle<JSObject> holder = args.at<JSObject>(holder_index);
   PropertyCallbackArguments callback_args(isolate,
                                           interceptor_info->data(),
                                           *receiver,
@@ -1330,10 +1334,14 @@ static MaybeObject* LoadWithInterceptor(Arguments* args,
   ASSERT(kArgsOffset == 2);
   // No ReturnValue in interceptors.
   ASSERT_EQ(kArgsOffset + PCA::kArgsLength - 2, args->length());
-  Handle<JSObject> receiver_handle =
-      args->at<JSObject>(kArgsOffset - PCA::kThisIndex);
-  Handle<JSObject> holder_handle =
-      args->at<JSObject>(kArgsOffset - PCA::kHolderIndex);
+  int this_index = kArgsOffset - PCA::kThisIndex;
+  int holder_index = kArgsOffset - PCA::kHolderIndex;
+  if (PCA::kThisIndex < PCA::kReturnValueOffset)
+      this_index -= 2;
+  if (PCA::kHolderIndex < PCA::kReturnValueOffset)
+      holder_index -= 2;
+  Handle<JSObject> receiver_handle = args->at<JSObject>(this_index);
+  Handle<JSObject> holder_handle = args->at<JSObject>(holder_index);
 
   Isolate* isolate = receiver_handle->GetIsolate();