Handlify DebugLookupResultValue.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 4f340855e907380dc0fa7ceda43a18219fa13227..ef0a6333fb2b36db652e52480d05abdccbbc654d 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -10717,63 +10717,45 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_Break) {
 }
 
 
-static MaybeObject* DebugLookupResultValue(Heap* heap,
-                                           Object* receiver,
-                                           Name* name,
-                                           LookupResult* result,
-                                           bool* caught_exception) {
-  Object* value;
-  if (result->IsTransition()) return heap->undefined_value();
+static MaybeHandle<Object> DebugLookupResultValue(Isolate* isolate,
+                                                  Handle<Object> receiver,
+                                                  Handle<Name> name,
+                                                  LookupResult* result) {
+  Handle<Object> value = isolate->factory()->undefined_value();
   switch (result->type()) {
-    case NORMAL:
-      value = result->holder()->GetNormalizedProperty(result);
-      if (value->IsTheHole()) {
-        return heap->undefined_value();
-      }
-      return value;
-    case FIELD: {
-      Object* value;
-      MaybeObject* maybe_value =
-          JSObject::cast(result->holder())->FastPropertyAt(
-              result->representation(),
-              result->GetFieldIndex().field_index());
-      if (!maybe_value->To(&value)) return maybe_value;
-      if (value->IsTheHole()) {
-        return heap->undefined_value();
-      }
-      return value;
+    case NORMAL: {
+      value = JSObject::GetNormalizedProperty(
+          handle(result->holder(), isolate), result);
+      break;
     }
+    case FIELD:
+      value = JSObject::FastPropertyAt(handle(result->holder(), isolate),
+                                       result->representation(),
+                                       result->GetFieldIndex().field_index());
+      break;
     case CONSTANT:
-      return result->GetConstant();
+      return handle(result->GetConstant(), isolate);
     case CALLBACKS: {
-      Object* structure = result->GetCallbackObject();
+      Handle<Object> structure(result->GetCallbackObject(), isolate);
       if (structure->IsForeign() || structure->IsAccessorInfo()) {
-        Isolate* isolate = heap->isolate();
-        HandleScope scope(isolate);
-        MaybeHandle<Object> maybe_value = JSObject::GetPropertyWithCallback(
+        return JSObject::GetPropertyWithCallback(
             handle(result->holder(), isolate),
-            handle(receiver, isolate),
-            handle(structure, isolate),
-            handle(name, isolate));
-        Handle<Object> value;
-        if (maybe_value.ToHandle(&value)) return *value;
-        Object* exception = heap->isolate()->pending_exception();
-        heap->isolate()->clear_pending_exception();
-        if (caught_exception != NULL) *caught_exception = true;
-        return exception;
-      } else {
-        return heap->undefined_value();
+            receiver,
+            handle(result->GetCallbackObject(), isolate),
+            name);
       }
+      // Fall through;

[ulan, 2014/04/14 11:25:25]

"break" would be easier to read than "fall through".

[Yang, 2014/04/14 13:12:42]

Done.

     }
-    case INTERCEPTOR:
-      return heap->undefined_value();
     case HANDLER:

[ulan, 2014/04/14 11:25:25]

this was unreachable before.

[Yang, 2014/04/14 13:12:42]

Handler is now again unreachable. Debugger/proxy interaction will be fixed in a
future CL.

+    case INTERCEPTOR:
+      break;
     case NONEXISTENT:
       UNREACHABLE();
-      return heap->undefined_value();
+      break;
   }
-  UNREACHABLE();  // keep the compiler happy
-  return heap->undefined_value();
+  ASSERT(!value->IsTheHole() || result->IsReadOnly());
+  return value->IsTheHole()
+      ? Handle<Object>::cast(isolate->factory()->undefined_value()) : value;
 }
 
 
@@ -10847,29 +10829,23 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugGetPropertyDetails) {
         result_callback_obj = Handle<Object>(result.GetCallbackObject(),
                                              isolate);
       }
-      Smi* property_details = result.GetPropertyDetails().AsSmi();
-      // DebugLookupResultValue can cause GC so details from LookupResult needs
-      // to be copied to handles before this.
-      bool caught_exception = false;
-      Object* raw_value;
-      { MaybeObject* maybe_raw_value =
-            DebugLookupResultValue(isolate->heap(), *obj, *name,
-                                   &result, &caught_exception);
-        if (!maybe_raw_value->ToObject(&raw_value)) return maybe_raw_value;
-      }
-      Handle<Object> value(raw_value, isolate);
+
+      Handle<Object> value;
+      bool has_caught =
+          !DebugLookupResultValue(isolate, obj, name, &result).ToHandle(&value);
+      if (has_caught) value = handle(isolate->pending_exception(), isolate);
 
       // If the callback object is a fixed array then it contains JavaScript
       // getter and/or setter.
-      bool hasJavaScriptAccessors = result.IsPropertyCallbacks() &&
-                                    result_callback_obj->IsAccessorPair();
+      bool has_js_accessors = result.IsPropertyCallbacks() &&
+                              result_callback_obj->IsAccessorPair();
       Handle<FixedArray> details =
-          isolate->factory()->NewFixedArray(hasJavaScriptAccessors ? 5 : 2);
+          isolate->factory()->NewFixedArray(has_js_accessors ? 5 : 2);
       details->set(0, *value);
-      details->set(1, property_details);
-      if (hasJavaScriptAccessors) {
+      details->set(1, result.GetPropertyDetails().AsSmi());
+      if (has_js_accessors) {
         AccessorPair* accessors = AccessorPair::cast(*result_callback_obj);
-        details->set(2, isolate->heap()->ToBoolean(caught_exception));
+        details->set(2, isolate->heap()->ToBoolean(has_caught));
         details->set(3, accessors->GetComponent(ACCESSOR_GETTER));
         details->set(4, accessors->GetComponent(ACCESSOR_SETTER));
       }
@@ -10895,10 +10871,10 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugGetProperty) {
 
   LookupResult result(isolate);
   obj->Lookup(*name, &result);
-  if (result.IsFound()) {
-    return DebugLookupResultValue(isolate->heap(), *obj, *name, &result, NULL);
-  }
-  return isolate->heap()->undefined_value();
+  Handle<Object> value;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, value, DebugLookupResultValue(isolate, obj, name, &result));
+  return *value;
 }