Fast path for strict closure creation.

src/x64/code-stubs-x64.cc

 // Copyright 2011 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 50 matching lines @@
 
 void FastNewClosureStub::Generate(MacroAssembler* masm) {
   // Create a new closure from the given function info in new
   // space. Set the context to the current context in rsi.
   Label gc;
   __ AllocateInNewSpace(JSFunction::kSize, rax, rbx, rcx, &gc, TAG_OBJECT);
 
   // Get the function info from the stack.
   __ movq(rdx, Operand(rsp, 1 * kPointerSize));
 
+  int map_index = strict_mode_ == kStrictMode
+      ? Context::FUNCTION_MAP_STRICT_INDEX
+      : Context::FUNCTION_MAP_INDEX;
+
   // Compute the function map in the current global context and set that
   // as the map of the allocated object.
   __ movq(rcx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
   __ movq(rcx, FieldOperand(rcx, GlobalObject::kGlobalContextOffset));
-  __ movq(rcx, Operand(rcx, Context::SlotOffset(Context::FUNCTION_MAP_INDEX)));
+  __ movq(rcx, Operand(rcx, Context::SlotOffset(map_index)));
   __ movq(FieldOperand(rax, JSObject::kMapOffset), rcx);
 
   // Initialize the rest of the function. We don't have to update the
   // write barrier because the allocated object is in new space.
   __ LoadRoot(rbx, Heap::kEmptyFixedArrayRootIndex);
   __ LoadRoot(rcx, Heap::kTheHoleValueRootIndex);
   __ LoadRoot(rdi, Heap::kUndefinedValueRootIndex);
   __ movq(FieldOperand(rax, JSObject::kPropertiesOffset), rbx);
   __ movq(FieldOperand(rax, JSObject::kElementsOffset), rbx);
   __ movq(FieldOperand(rax, JSFunction::kPrototypeOrInitialMapOffset), rcx);
@@ skipping 4938 matching lines @@
   // Do a tail call to the rewritten stub.
   __ jmp(rdi);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64