Introduce Object::DebugGetProperty.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 4f340855e907380dc0fa7ceda43a18219fa13227..094f262df37328b8d60179e57077dfed7d891eab 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -10717,66 +10717,6 @@ 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();
-  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 CONSTANT:
-      return result->GetConstant();
-    case CALLBACKS: {
-      Object* structure = result->GetCallbackObject();
-      if (structure->IsForeign() || structure->IsAccessorInfo()) {

[ulan, 2014/04/14 08:39:35]

After this change, we no longer check for: structure->IsForeign() ||
structure->IsAccessorInfo()

-        Isolate* isolate = heap->isolate();
-        HandleScope scope(isolate);
-        MaybeHandle<Object> maybe_value = 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();
-      }
-    }
-    case INTERCEPTOR:
-      return heap->undefined_value();

[ulan, 2014/04/14 08:39:35]

After this change, this can return other values.

-    case HANDLER:
-    case NONEXISTENT:
-      UNREACHABLE();
-      return heap->undefined_value();
-  }
-  UNREACHABLE();  // keep the compiler happy
-  return heap->undefined_value();
-}
-
-
 // Get debugger related details for an object property.
 // args[0]: object holding property
 // args[1]: name of the property
@@ -10847,29 +10787,22 @@ 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);
+
+      bool has_caught;
+      Handle<Object> value = Object::DebugGetProperty(
+          obj, name, &result, &has_caught);
 
       // 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 +10828,7 @@ 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();
+  return *Object::DebugGetProperty(obj, name, &result);
 }