Port FastNewContextStub to x64 and arm.

BUG=551
Review URL: http://codereview.chromium.org/541027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3592 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/codegen-arm.cc

@@ -187,12 +187,18 @@ void CodeGenerator::GenCode(FunctionLiteral* fun) {
     function_return_is_shadowed_ = false;
 
     VirtualFrame::SpilledScope spilled_scope;
-    if (scope_->num_heap_slots() > 0) {
+    int heap_slots = scope_->num_heap_slots();
+    if (heap_slots > 0) {
       // Allocate local context.
       // Get outer context and create a new context based on it.
       __ ldr(r0, frame_->Function());
       frame_->EmitPush(r0);
-      frame_->CallRuntime(Runtime::kNewContext, 1);  // r0 holds the result
+      if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+        FastNewContextStub stub(heap_slots);
+        frame_->CallStub(&stub, 1);
+      } else {
+        frame_->CallRuntime(Runtime::kNewContext, 1);
+      }
 
 #ifdef DEBUG
       JumpTarget verified_true;
@@ -4444,6 +4450,55 @@ void FastNewClosureStub::Generate(MacroAssembler* masm) {
 }
 
 
+void FastNewContextStub::Generate(MacroAssembler* masm) {
+  // Try to allocate the context in new space.
+  Label gc;
+  int length = slots_ + Context::MIN_CONTEXT_SLOTS;
+
+  // Pop the function from the stack.
+  __ pop(r3);
+
+  // Attempt to allocate the context in new space.
+  __ AllocateInNewSpace(length + (FixedArray::kHeaderSize / kPointerSize),
+                        r0,
+                        r1,
+                        r2,
+                        &gc,
+                        TAG_OBJECT);
+
+  // Setup the object header.
+  __ LoadRoot(r2, Heap::kContextMapRootIndex);
+  __ str(r2, FieldMemOperand(r0, HeapObject::kMapOffset));
+  __ mov(r2, Operand(length));
+  __ str(r2, FieldMemOperand(r0, Array::kLengthOffset));
+
+  // Setup the fixed slots.
+  __ mov(r1, Operand(Smi::FromInt(0)));
+  __ str(r3, MemOperand(r0, Context::SlotOffset(Context::CLOSURE_INDEX)));
+  __ str(r0, MemOperand(r0, Context::SlotOffset(Context::FCONTEXT_INDEX)));
+  __ str(r1, MemOperand(r0, Context::SlotOffset(Context::PREVIOUS_INDEX)));
+  __ str(r1, MemOperand(r0, Context::SlotOffset(Context::EXTENSION_INDEX)));
+
+  // Copy the global object from the surrounding context.
+  __ ldr(r1, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ str(r1, MemOperand(r0, Context::SlotOffset(Context::GLOBAL_INDEX)));
+
+  // Initialize the rest of the slots to undefined.
+  __ LoadRoot(r1, Heap::kUndefinedValueRootIndex);
+  for (int i = Context::MIN_CONTEXT_SLOTS; i < length; i++) {
+    __ str(r1, MemOperand(r0, Context::SlotOffset(i)));
+  }
+
+  // Return. The on-stack parameter has already been popped.
+  __ mov(cp, r0);
+  __ Ret();
+
+  // Need to collect. Call into runtime system.
+  __ bind(&gc);
+  __ TailCallRuntime(ExternalReference(Runtime::kNewContext), 1, 1);
+}
+
+
 // Count leading zeros in a 32 bit word.  On ARM5 and later it uses the clz
 // instruction.  On pre-ARM5 hardware this routine gives the wrong answer for 0
 // (31 instead of 32).

src/x64/codegen-x64.cc

@@ -326,12 +326,19 @@ void CodeGenerator::GenCode(FunctionLiteral* function) {
     function_return_is_shadowed_ = false;
 
     // Allocate the local context if needed.
-    if (scope_->num_heap_slots() > 0) {
+    int heap_slots = scope_->num_heap_slots();
+    if (heap_slots > 0) {
       Comment cmnt(masm_, "[ allocate local context");
       // Allocate local context.
       // Get outer context and create a new context based on it.
       frame_->PushFunction();
-      Result context = frame_->CallRuntime(Runtime::kNewContext, 1);
+      Result context;
+      if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+        FastNewContextStub stub(heap_slots);
+        context = frame_->CallStub(&stub, 1);
+      } else {
+        context = frame_->CallRuntime(Runtime::kNewContext, 1);
+      }
 
       // Update context local.
       frame_->SaveContextRegister();
@@ -6116,6 +6123,48 @@ void FastNewClosureStub::Generate(MacroAssembler* masm) {
 }
 
 
+void FastNewContextStub::Generate(MacroAssembler* masm) {
+  // Try to allocate the context in new space.
+  Label gc;
+  int length = slots_ + Context::MIN_CONTEXT_SLOTS;
+  __ AllocateInNewSpace((length * kPointerSize) + FixedArray::kHeaderSize,
+                        rax, rbx, rcx, &gc, TAG_OBJECT);
+
+  // Get the function from the stack.
+  __ movq(rcx, Operand(rsp, 1 * kPointerSize));
+
+  // Setup the object header.
+  __ LoadRoot(kScratchRegister, Heap::kContextMapRootIndex);
+  __ movq(FieldOperand(rax, HeapObject::kMapOffset), kScratchRegister);
+  __ movl(FieldOperand(rax, Array::kLengthOffset), Immediate(length));
+
+  // Setup the fixed slots.
+  __ xor_(rbx, rbx);  // Set to NULL.
+  __ movq(Operand(rax, Context::SlotOffset(Context::CLOSURE_INDEX)), rcx);
+  __ movq(Operand(rax, Context::SlotOffset(Context::FCONTEXT_INDEX)), rax);
+  __ movq(Operand(rax, Context::SlotOffset(Context::PREVIOUS_INDEX)), rbx);
+  __ movq(Operand(rax, Context::SlotOffset(Context::EXTENSION_INDEX)), rbx);
+
+  // Copy the global object from the surrounding context.
+  __ movq(rbx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ movq(Operand(rax, Context::SlotOffset(Context::GLOBAL_INDEX)), rbx);
+
+  // Initialize the rest of the slots to undefined.
+  __ LoadRoot(rbx, Heap::kUndefinedValueRootIndex);
+  for (int i = Context::MIN_CONTEXT_SLOTS; i < length; i++) {
+    __ movq(Operand(rax, Context::SlotOffset(i)), rbx);
+  }
+
+  // Return and remove the on-stack parameter.
+  __ movq(rsi, rax);
+  __ ret(1 * kPointerSize);
+
+  // Need to collect. Call into runtime system.
+  __ bind(&gc);
+  __ TailCallRuntime(ExternalReference(Runtime::kNewContext), 1, 1);
+}
+
+
 void ToBooleanStub::Generate(MacroAssembler* masm) {
   Label false_result, true_result, not_string;
   __ movq(rax, Operand(rsp, 1 * kPointerSize));