Fixed Accessors::FunctionGetPrototype's proto chain traversal.

src/accessors.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 24 matching lines @@
 #include "frames-inl.h"
 #include "isolate.h"
 #include "list-inl.h"
 #include "property-details.h"
 
 namespace v8 {
 namespace internal {
 
 
 template <class C>
-static C* FindInPrototypeChain(Object* obj, bool* found_it) {
-  ASSERT(!*found_it);
-  Heap* heap = HEAP;
-  while (!Is<C>(obj)) {
-    if (obj == heap->null_value()) return NULL;
-    obj = obj->GetPrototype();
+static C* FindInstanceOf(Object* obj) {
+  for (Object* cur = obj; !cur->IsNull(); cur = cur->GetPrototype()) {
+    if (Is<C>(cur)) return C::cast(cur);
   }
-  *found_it = true;
-  return C::cast(obj);
+  return NULL;
 }
 
 
 // Entry point that never should be called.
 MaybeObject* Accessors::IllegalSetter(JSObject*, Object*, void*) {
   UNREACHABLE();
   return NULL;
 }
 
 
@@ skipping 10 matching lines @@
 }
 
 
 //
 // Accessors::ArrayLength
 //
 
 
 MaybeObject* Accessors::ArrayGetLength(Object* object, void*) {
   // Traverse the prototype chain until we reach an array.
-  bool found_it = false;
-  JSArray* holder = FindInPrototypeChain<JSArray>(object, &found_it);
-  if (!found_it) return Smi::FromInt(0);
-  return holder->length();
+  JSArray* holder = FindInstanceOf<JSArray>(object);
+  return holder == NULL ? Smi::FromInt(0) : holder->length();
 }
 
 
 // The helper function will 'flatten' Number objects.
 Object* Accessors::FlattenNumber(Object* value) {
   if (value->IsNumber() || !value->IsJSValue()) return value;
   JSValue* wrapper = JSValue::cast(value);
   ASSERT(Isolate::Current()->context()->native_context()->number_function()->
       has_initial_map());
   Map* number_map = Isolate::Current()->context()->native_context()->
@@ skipping 343 matching lines @@
 };
 
 
 //
 // Accessors::FunctionPrototype
 //
 
 
 MaybeObject* Accessors::FunctionGetPrototype(Object* object, void*) {
   Heap* heap = Isolate::Current()->heap();
-  bool found_it = false;
-  JSFunction* function = FindInPrototypeChain<JSFunction>(object, &found_it);
-  if (!found_it) return heap->undefined_value();
+  JSFunction* function = FindInstanceOf<JSFunction>(object);
+  if (function == NULL) return heap->undefined_value();
   while (!function->should_have_prototype()) {
-    found_it = false;
-    function = FindInPrototypeChain<JSFunction>(object->GetPrototype(),
-                                                &found_it);
+    function = FindInstanceOf<JSFunction>(function->GetPrototype());
     // There has to be one because we hit the getter.
-    ASSERT(found_it);
+    ASSERT(function != NULL);
   }
 
   if (!function->has_prototype()) {
     Object* prototype;
     { MaybeObject* maybe_prototype = heap->AllocateFunctionPrototype(function);
       if (!maybe_prototype->ToObject(&prototype)) return maybe_prototype;
     }
     Object* result;
     { MaybeObject* maybe_result = function->SetPrototype(prototype);
       if (!maybe_result->ToObject(&result)) return maybe_result;
     }
   }
   return function->prototype();
 }
 
 
 MaybeObject* Accessors::FunctionSetPrototype(JSObject* object,
                                              Object* value,
                                              void*) {
   Heap* heap = object->GetHeap();
-  bool found_it = false;
-  JSFunction* function = FindInPrototypeChain<JSFunction>(object, &found_it);
-  if (!found_it) return heap->undefined_value();
+  JSFunction* function = FindInstanceOf<JSFunction>(object);
+  if (function == NULL) return heap->undefined_value();
   if (!function->should_have_prototype()) {
     // Since we hit this accessor, object will have no prototype property.
     return object->SetLocalPropertyIgnoreAttributes(heap->prototype_symbol(),
                                                     value,
                                                     NONE);
   }
 
   Object* prototype;
   { MaybeObject* maybe_prototype = function->SetPrototype(value);
     if (!maybe_prototype->ToObject(&prototype)) return maybe_prototype;
   }
   ASSERT(function->prototype() == value);
   return function;
 }
 
 
 const AccessorDescriptor Accessors::FunctionPrototype = {
   FunctionGetPrototype,
   FunctionSetPrototype,
   0
 };
 
 
 //
 // Accessors::FunctionLength
 //
 
 
 MaybeObject* Accessors::FunctionGetLength(Object* object, void*) {
-  bool found_it = false;
-  JSFunction* function = FindInPrototypeChain<JSFunction>(object, &found_it);
-  if (!found_it) return Smi::FromInt(0);
+  JSFunction* function = FindInstanceOf<JSFunction>(object);
+  if (function == NULL) return Smi::FromInt(0);
   // Check if already compiled.
-  if (!function->shared()->is_compiled()) {
-    // If the function isn't compiled yet, the length is not computed
-    // correctly yet. Compile it now and return the right length.
-    HandleScope scope;
-    Handle<JSFunction> handle(function);
-    if (!JSFunction::CompileLazy(handle, KEEP_EXCEPTION)) {
-      return Failure::Exception();
-    }
-    return Smi::FromInt(handle->shared()->length());
-  } else {
+  if (function->shared()->is_compiled()) {
     return Smi::FromInt(function->shared()->length());
   }
+  // If the function isn't compiled yet, the length is not computed correctly
+  // yet. Compile it now and return the right length.
+  HandleScope scope;
+  Handle<JSFunction> handle(function);
+  if (JSFunction::CompileLazy(handle, KEEP_EXCEPTION)) {
+    return Smi::FromInt(handle->shared()->length());
+  }
+  return Failure::Exception();
 }
 
 
 const AccessorDescriptor Accessors::FunctionLength = {
   FunctionGetLength,
   ReadOnlySetAccessor,
   0
 };
 
 
 //
 // Accessors::FunctionName
 //
 
 
 MaybeObject* Accessors::FunctionGetName(Object* object, void*) {
-  bool found_it = false;
-  JSFunction* holder = FindInPrototypeChain<JSFunction>(object, &found_it);
-  if (!found_it) return HEAP->undefined_value();
-  return holder->shared()->name();
+  JSFunction* holder = FindInstanceOf<JSFunction>(object);
+  return holder == NULL ? HEAP->undefined_value() : holder->shared()->name();
 }
 
 
 const AccessorDescriptor Accessors::FunctionName = {
   FunctionGetName,
   ReadOnlySetAccessor,
   0
 };
 
 
@@ skipping 24 matching lines @@
   args_slots.Dispose();
 
   // Return the freshly allocated arguments object.
   return *arguments;
 }
 
 
 MaybeObject* Accessors::FunctionGetArguments(Object* object, void*) {
   Isolate* isolate = Isolate::Current();
   HandleScope scope(isolate);
-  bool found_it = false;
-  JSFunction* holder = FindInPrototypeChain<JSFunction>(object, &found_it);
-  if (!found_it) return isolate->heap()->undefined_value();
+  JSFunction* holder = FindInstanceOf<JSFunction>(object);
+  if (holder == NULL) return isolate->heap()->undefined_value();
   Handle<JSFunction> function(holder, isolate);
 
   if (function->shared()->native()) return isolate->heap()->null_value();
   // Find the top invocation of the function by traversing frames.
   List<JSFunction*> functions(2);
   for (JavaScriptFrameIterator it(isolate); !it.done(); it.Advance()) {
     JavaScriptFrame* frame = it.frame();
     frame->GetFunctions(&functions);
     for (int i = functions.length() - 1; i >= 0; i--) {
       // Skip all frames that aren't invocations of the given function.
@@ skipping 115 matching lines @@
   JavaScriptFrameIterator frame_iterator_;
   List<JSFunction*> functions_;
   int index_;
 };
 
 
 MaybeObject* Accessors::FunctionGetCaller(Object* object, void*) {
   Isolate* isolate = Isolate::Current();
   HandleScope scope(isolate);
   AssertNoAllocation no_alloc;
-  bool found_it = false;
-  JSFunction* holder = FindInPrototypeChain<JSFunction>(object, &found_it);
-  if (!found_it) return isolate->heap()->undefined_value();
+  JSFunction* holder = FindInstanceOf<JSFunction>(object);
+  if (holder == NULL) return isolate->heap()->undefined_value();
   if (holder->shared()->native()) return isolate->heap()->null_value();
   Handle<JSFunction> function(holder, isolate);
 
   FrameFunctionIterator it(isolate, no_alloc);
 
   // Find the function from the frames.
   if (!it.Find(*function)) {
     // No frame corresponding to the given function found. Return null.
     return isolate->heap()->null_value();
   }
@@ skipping 121 matching lines @@
   info->set_data(Smi::FromInt(index));
   Handle<Object> getter = v8::FromCData(&ModuleGetExport);
   Handle<Object> setter = v8::FromCData(&ModuleSetExport);
   info->set_getter(*getter);
   if (!(attributes & ReadOnly)) info->set_setter(*setter);
   return info;
 }
 
 
 } }  // namespace v8::internal