Improve performance of arguments object allocation by taking...

src/runtime.cc

 // Copyright 2006-2008 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 2685 matching lines @@
 
 static Object* Runtime_Math_tan(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
   CONVERT_DOUBLE_CHECKED(x, args[0]);
   return Heap::AllocateHeapNumber(tan(x));
 }
 
 
+// The NewArguments function is only used when constructing the
+// arguments array when calling non-functions from JavaScript in
+// runtime.js:CALL_NON_FUNCTION.
 static Object* Runtime_NewArguments(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
 
   // ECMA-262, 3rd., 10.1.8, p.39
   CONVERT_CHECKED(JSFunction, callee, args[0]);
 
   // Compute the frame holding the arguments.
   JavaScriptFrameIterator it;
   it.AdvanceToArgumentsFrame();
   JavaScriptFrame* frame = it.frame();
 
   const int length = frame->GetProvidedParametersCount();
   Object* result = Heap::AllocateArgumentsObject(callee, length);
   if (result->IsFailure()) return result;
   FixedArray* array = FixedArray::cast(JSObject::cast(result)->elements());
   ASSERT(array->length() == length);
   for (int i = 0; i < length; i++) {
     array->set(i, frame->GetParameter(i));
   }
   return result;
 }
 
 
+static Object* Runtime_NewArgumentsFast(Arguments args) {
+  NoHandleAllocation ha;
+  ASSERT(args.length() == 3);
+
+  JSFunction* callee = JSFunction::cast(args[0]);
+  Object** parameters = reinterpret_cast<Object**>(args[1]);
+  const int length = Smi::cast(args[2])->value();
+
+  Object* result = Heap::AllocateArgumentsObject(callee, length);
+  if (result->IsFailure()) return result;
+  FixedArray* array = FixedArray::cast(JSObject::cast(result)->elements());
+  ASSERT(array->length() == length);
+  FixedArray::WriteBarrierMode mode = array->GetWriteBarrierMode();
+  for (int i = 0; i < length; i++) {
+    array->set(i, *--parameters, mode);
+  }
+  return result;
+}
+
+
 static Object* Runtime_NewClosure(Arguments args) {
   HandleScope scope;
   ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(JSFunction, boilerplate, 0);
   CONVERT_ARG_CHECKED(Context, context, 1);
 
   Handle<JSFunction> result =
       Factory::NewFunctionFromBoilerplate(boilerplate, context);
   return *result;
 }
@@ skipping 2287 matching lines @@
 
 void Runtime::PerformGC(Object* result) {
   Failure* failure = Failure::cast(result);
   // Try to do a garbage collection; ignore it if it fails. The C
   // entry stub will throw an out-of-memory exception in that case.
   Heap::CollectGarbage(failure->requested(), failure->allocation_space());
 }
 
 
 } }  // namespace v8::internal