Port arguments object allocation in generated code to ARM and x64....

src/x64/codegen-x64.cc

Index: src/x64/codegen-x64.cc
===================================================================
--- src/x64/codegen-x64.cc	(revision 3863)
+++ src/x64/codegen-x64.cc	(working copy)
@@ -7401,30 +7401,107 @@
 
 
 void ArgumentsAccessStub::GenerateNewObject(MacroAssembler* masm) {
+  // rsp[0] : return address
+  // rsp[8] : number of parameters
+  // rsp[16] : receiver displacement
+  // rsp[24] : function
+
   // The displacement is used for skipping the return address and the
   // frame pointer on the stack. It is the offset of the last
   // parameter (if any) relative to the frame pointer.
   static const int kDisplacement = 2 * kPointerSize;
 
   // Check if the calling frame is an arguments adaptor frame.
-  Label runtime;
+  Label adaptor_frame, try_allocate, runtime;
   __ movq(rdx, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
   __ SmiCompare(Operand(rdx, StandardFrameConstants::kContextOffset),
                 Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
-  __ j(not_equal, &runtime);
-  // Value in rcx is Smi encoded.
+  __ j(equal, &adaptor_frame);
 
+  // Get the length from the frame.
+  __ movq(rcx, Operand(rsp, 1 * kPointerSize));
+  __ jmp(&try_allocate);
+
   // Patch the arguments.length and the parameters pointer.
+  __ bind(&adaptor_frame);
   __ movq(rcx, Operand(rdx, ArgumentsAdaptorFrameConstants::kLengthOffset));
   __ movq(Operand(rsp, 1 * kPointerSize), rcx);
-  SmiIndex index = masm->SmiToIndex(rcx, rcx, kPointerSizeLog2);
+  // Do not clobber the length index for the indexing operation since
+  // it is used compute the size for allocation later.
+  SmiIndex index = masm->SmiToIndex(rbx, rcx, kPointerSizeLog2);
   __ lea(rdx, Operand(rdx, index.reg, index.scale, kDisplacement));
   __ movq(Operand(rsp, 2 * kPointerSize), rdx);
 
+  // Try the new space allocation. Start out with computing the size of
+  // the arguments object and the elements array.
+  Label add_arguments_object;
+  __ bind(&try_allocate);
+  __ testq(rcx, rcx);
+  __ j(zero, &add_arguments_object);
+  index = masm->SmiToIndex(rcx, rcx, kPointerSizeLog2);
+  __ lea(rcx, Operand(index.reg, index.scale, FixedArray::kHeaderSize));
+  __ bind(&add_arguments_object);
+  __ addq(rcx, Immediate(Heap::kArgumentsObjectSize));
+
+  // Do the allocation of both objects in one go.
+  __ AllocateInNewSpace(rcx, rax, rdx, rbx, &runtime, TAG_OBJECT);
+
+  // Get the arguments boilerplate from the current (global) context.
+  int offset = Context::SlotOffset(Context::ARGUMENTS_BOILERPLATE_INDEX);
+  __ movq(rdi, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ movq(rdi, FieldOperand(rdi, GlobalObject::kGlobalContextOffset));
+  __ movq(rdi, Operand(rdi, offset));
+
+  // Copy the JS object part.
+  for (int i = 0; i < JSObject::kHeaderSize; i += kPointerSize) {
+    __ movq(kScratchRegister, FieldOperand(rdi, i));
+    __ movq(FieldOperand(rax, i), kScratchRegister);
+  }
+
+  // Setup the callee in-object property.
+  ASSERT(Heap::arguments_callee_index == 0);
+  __ movq(kScratchRegister, Operand(rsp, 3 * kPointerSize));
+  __ movq(FieldOperand(rax, JSObject::kHeaderSize), kScratchRegister);
+
+  // Get the length (smi tagged) and set that as an in-object property too.
+  ASSERT(Heap::arguments_length_index == 1);
+  __ movq(rcx, Operand(rsp, 1 * kPointerSize));
+  __ movq(FieldOperand(rax, JSObject::kHeaderSize + kPointerSize), rcx);
+
+  // If there are no actual arguments, we're done.
+  Label done;
+  __ testq(rcx, rcx);
+  __ j(zero, &done);
+
+  // Get the parameters pointer from the stack and untag the length.
+  __ movq(rdx, Operand(rsp, 2 * kPointerSize));
+  __ SmiToInteger32(rcx, rcx);
+
+  // Setup the elements pointer in the allocated arguments object and
+  // initialize the header in the elements fixed array.
+  __ lea(rdi, Operand(rax, Heap::kArgumentsObjectSize));
+  __ movq(FieldOperand(rax, JSObject::kElementsOffset), rdi);
+  __ LoadRoot(kScratchRegister, Heap::kFixedArrayMapRootIndex);
+  __ movq(FieldOperand(rdi, FixedArray::kMapOffset), kScratchRegister);
+  __ movq(FieldOperand(rdi, FixedArray::kLengthOffset), rcx);
+
+  // Copy the fixed array slots.
+  Label loop;
+  __ bind(&loop);
+  __ movq(kScratchRegister, Operand(rdx, -1 * kPointerSize));  // Skip receiver.
+  __ movq(FieldOperand(rdi, FixedArray::kHeaderSize), kScratchRegister);
+  __ addq(rdi, Immediate(kPointerSize));
+  __ subq(rdx, Immediate(kPointerSize));
+  __ decq(rcx);
+  __ j(not_zero, &loop);
+
+  // Return and remove the on-stack parameters.
+  __ bind(&done);
+  __ ret(3 * kPointerSize);
+
   // Do the runtime call to allocate the arguments object.
   __ bind(&runtime);
-  Runtime::Function* f = Runtime::FunctionForId(Runtime::kNewArgumentsFast);
-  __ TailCallRuntime(ExternalReference(f), 3, f->result_size);
+  __ TailCallRuntime(ExternalReference(Runtime::kNewArgumentsFast), 3, 1);
 }