Always cache the original target in a handle on the IC.

This requires us to always open a handle-scope in the miss handlers.

BUG=
R=ulan@chromium.org

Review URL: https://chromiumcodereview.appspot.com/25238002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17037 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ic.h

@@ -95,7 +95,9 @@ class IC {
   virtual ~IC() {}
 
   // Get the call-site target; used for determining the state.
-  Code* target() const { return GetTargetAtAddress(address()); }
+  Handle<Code> target() const { return target_; }
+  Code* raw_target() const { return GetTargetAtAddress(address()); }
+
   inline Address address() const;
 
   // Compute the current IC state based on the target stub, receiver and name.
@@ -210,6 +212,9 @@ class IC {
 
   Isolate* isolate_;
 
+  // The original code target that missed.
+  Handle<Code> target_;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(IC);
 };
 

src/stub-cache.cc

@@ -1257,12 +1257,12 @@ static MaybeObject* ThrowReferenceError(Isolate* isolate, Name* name) {
   // If the load is non-contextual, just return the undefined result.
   // Note that both keyed and non-keyed loads may end up here, so we
   // can't use either LoadIC or KeyedLoadIC constructors.
+  HandleScope scope(isolate);
   IC ic(IC::NO_EXTRA_FRAME, isolate);
   ASSERT(ic.target()->is_load_stub() || ic.target()->is_keyed_load_stub());
   if (!ic.SlowIsUndeclaredGlobal()) return isolate->heap()->undefined_value();
 
   // Throw a reference error.
-  HandleScope scope(isolate);
   Handle<Name> name_handle(name);
   Handle<Object> error =
       isolate->factory()->NewReferenceError("not_defined",