Fix issue 656 on x64.

src/x64/codegen-x64.cc

Index: src/x64/codegen-x64.cc
===================================================================
--- src/x64/codegen-x64.cc	(revision 4211)
+++ src/x64/codegen-x64.cc	(working copy)
@@ -2238,8 +2238,7 @@
 
   // Use the fast case closure allocation code that allocates in new
   // space for nested functions that don't need literals cloning.
-  if (false && scope()->is_function_scope() &&
-      function_info->num_literals() == 0) {
+  if (scope()->is_function_scope() && function_info->num_literals() == 0) {
     FastNewClosureStub stub;
     frame_->Push(function_info);
     Result answer = frame_->CallStub(&stub, 1);
@@ -6361,12 +6360,12 @@
 
 
 void FastNewClosureStub::Generate(MacroAssembler* masm) {
-  // Clone the boilerplate in new space. Set the context to the
-  // current context in rsi.
+  // 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 boilerplate function from the stack.
+  // Get the function info from the stack.
   __ movq(rdx, Operand(rsp, 1 * kPointerSize));
 
   // Compute the function map in the current global context and set that
@@ -6376,18 +6375,16 @@
   __ movq(rcx, Operand(rcx, Context::SlotOffset(Context::FUNCTION_MAP_INDEX)));
   __ movq(FieldOperand(rax, JSObject::kMapOffset), rcx);
 
-  // Clone the rest of the boilerplate fields. We don't have to update
-  // the write barrier because the allocated object is in new space.
-  for (int offset = kPointerSize;
-       offset < JSFunction::kSize;
-       offset += kPointerSize) {
-    if (offset == JSFunction::kContextOffset) {
-      __ movq(FieldOperand(rax, offset), rsi);
-    } else {
-      __ movq(rbx, FieldOperand(rdx, offset));
-      __ movq(FieldOperand(rax, offset), rbx);
-    }
-  }
+  // 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);
+  __ movq(FieldOperand(rax, JSObject::kPropertiesOffset), rbx);
+  __ movq(FieldOperand(rax, JSObject::kElementsOffset), rbx);
+  __ movq(FieldOperand(rax, JSFunction::kPrototypeOrInitialMapOffset), rcx);
+  __ movq(FieldOperand(rax, JSFunction::kSharedFunctionInfoOffset), rdx);
+  __ movq(FieldOperand(rax, JSFunction::kContextOffset), rsi);
+  __ movq(FieldOperand(rax, JSFunction::kLiteralsOffset), rbx);
 
   // Return and remove the on-stack parameter.
   __ ret(1 * kPointerSize);