Introduce MaybeHandle to police exception checking in handlified code.

src/runtime.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 3220 matching lines @@
   Vector< Handle<Object> > argv = HandleVector<Object>(NULL, 0);
   Handle<Object> error = isolate->factory()->NewError(message, argv);
   return isolate->Throw(*error);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ObjectFreeze) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, object, 0);
-  Handle<Object> result = JSObject::Freeze(object);
-  RETURN_IF_EMPTY_HANDLE(isolate, result);
+  Handle<Object> result;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, JSObject::Freeze(object));
   return *result;
 }
 
 
 MUST_USE_RESULT static MaybeObject* CharFromCode(Isolate* isolate,
                                                  Object* char_code) {
   if (char_code->IsNumber()) {
     return isolate->heap()->LookupSingleCharacterStringFromCode(
         NumberToUint32(char_code) & 0xffff);
   }
@@ skipping 9058 matching lines @@
   }
   return *array;
 }
 
 
 static const int kScopeDetailsTypeIndex = 0;
 static const int kScopeDetailsObjectIndex = 1;
 static const int kScopeDetailsSize = 2;
 
 
-static Handle<JSObject> MaterializeScopeDetails(Isolate* isolate,
-    ScopeIterator* it) {
+static MaybeHandle<JSObject> MaterializeScopeDetails(Isolate* isolate,
+                                                     ScopeIterator* it) {
   // Calculate the size of the result.
   int details_size = kScopeDetailsSize;
   Handle<FixedArray> details = isolate->factory()->NewFixedArray(details_size);
 
   // Fill in scope details.
   details->set(kScopeDetailsTypeIndex, Smi::FromInt(it->Type()));
-  Handle<JSObject> scope_object = it->ScopeObject();
-  RETURN_IF_EMPTY_HANDLE_VALUE(isolate, scope_object, Handle<JSObject>());
+  Handle<JSObject> scope_object;
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate, scope_object, it->ScopeObject(), JSObject);
   details->set(kScopeDetailsObjectIndex, *scope_object);
 
   return isolate->factory()->NewJSArrayWithElements(details);
 }
 
 
 // Return an array with scope details
 // args[0]: number: break id
 // args[1]: number: frame index
 // args[2]: number: inlined frame index
@@ skipping 23 matching lines @@
 
   // Find the requested scope.
   int n = 0;
   ScopeIterator it(isolate, frame, inlined_jsframe_index);
   for (; !it.Done() && n < index; it.Next()) {
     n++;
   }
   if (it.Done()) {
     return isolate->heap()->undefined_value();
   }
-  Handle<JSObject> details = MaterializeScopeDetails(isolate, &it);
-  RETURN_IF_EMPTY_HANDLE(isolate, details);
+  Handle<JSObject> details;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, details, MaterializeScopeDetails(isolate, &it));
   return *details;
 }
 
 
 // Return an array of scope details
 // args[0]: number: break id
 // args[1]: number: frame index
 // args[2]: number: inlined frame index
 // args[3]: boolean: ignore nested scopes
 //
@@ skipping 20 matching lines @@
   }
 
   // Get the frame where the debugging is performed.
   StackFrame::Id id = UnwrapFrameId(wrapped_id);
   JavaScriptFrameIterator frame_it(isolate, id);
   JavaScriptFrame* frame = frame_it.frame();
 
   List<Handle<JSObject> > result(4);
   ScopeIterator it(isolate, frame, inlined_jsframe_index, ignore_nested_scopes);
   for (; !it.Done(); it.Next()) {
-    Handle<JSObject> details = MaterializeScopeDetails(isolate, &it);
-    RETURN_IF_EMPTY_HANDLE(isolate, details);
+    Handle<JSObject> details;
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, details, MaterializeScopeDetails(isolate, &it));
     result.Add(details);
   }
 
   Handle<FixedArray> array = isolate->factory()->NewFixedArray(result.length());
   for (int i = 0; i < result.length(); ++i) {
     array->set(i, *result[i]);
   }
   return *isolate->factory()->NewJSArrayWithElements(array);
 }
 
@@ skipping 26 matching lines @@
   // Find the requested scope.
   int n = 0;
   ScopeIterator it(isolate, fun);
   for (; !it.Done() && n < index; it.Next()) {
     n++;
   }
   if (it.Done()) {
     return isolate->heap()->undefined_value();
   }
 
-  Handle<JSObject> details = MaterializeScopeDetails(isolate, &it);
-  RETURN_IF_EMPTY_HANDLE(isolate, details);
+  Handle<JSObject> details;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, details, MaterializeScopeDetails(isolate, &it));
   return *details;
 }
 
 
 static bool SetScopeVariableValue(ScopeIterator* it, int index,
                                   Handle<String> variable_name,
                                   Handle<Object> new_value) {
   for (int n = 0; !it->Done() && n < index; it->Next()) {
     n++;
   }
@@ skipping 2755 matching lines @@
   }
 }
 
 
 void Runtime::OutOfMemory() {
   Heap::FatalProcessOutOfMemory("CALL_AND_RETRY_LAST", true);
   UNREACHABLE();
 }
 
 } }  // namespace v8::internal