MIPS: Turn FastNewContextStub into a HydrogenCodeStub.

Port r18764 (c40563f)

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/145013010

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18784 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/code-stubs-mips.cc

@@ -50,6 +50,16 @@ void FastNewClosureStub::InitializeInterfaceDescriptor(
 }
 
 
+void FastNewContextStub::InitializeInterfaceDescriptor(
+    Isolate* isolate,
+    CodeStubInterfaceDescriptor* descriptor) {
+  static Register registers[] = { a1 };
+  descriptor->register_param_count_ = 1;
+  descriptor->register_params_ = registers;
+  descriptor->deoptimization_handler_ = NULL;
+}
+
+
 void ToNumberStub::InitializeInterfaceDescriptor(
     Isolate* isolate,
     CodeStubInterfaceDescriptor* descriptor) {
@@ -453,47 +463,6 @@ void HydrogenCodeStub::GenerateLightweightMiss(MacroAssembler* masm) {
 }
 
 
-void FastNewContextStub::Generate(MacroAssembler* masm) {
-  // Try to allocate the context in new space.
-  Label gc;
-  int length = slots_ + Context::MIN_CONTEXT_SLOTS;
-
-  // Attempt to allocate the context in new space.
-  __ Allocate(FixedArray::SizeFor(length), v0, a1, a2, &gc, TAG_OBJECT);
-
-  // Load the function from the stack.
-  __ lw(a3, MemOperand(sp, 0));
-
-  // Set up the object header.
-  __ LoadRoot(a1, Heap::kFunctionContextMapRootIndex);
-  __ li(a2, Operand(Smi::FromInt(length)));
-  __ sw(a2, FieldMemOperand(v0, FixedArray::kLengthOffset));
-  __ sw(a1, FieldMemOperand(v0, HeapObject::kMapOffset));
-
-  // Set up the fixed slots, copy the global object from the previous context.
-  __ lw(a2, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
-  __ li(a1, Operand(Smi::FromInt(0)));
-  __ sw(a3, MemOperand(v0, Context::SlotOffset(Context::CLOSURE_INDEX)));
-  __ sw(cp, MemOperand(v0, Context::SlotOffset(Context::PREVIOUS_INDEX)));
-  __ sw(a1, MemOperand(v0, Context::SlotOffset(Context::EXTENSION_INDEX)));
-  __ sw(a2, MemOperand(v0, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
-
-  // Initialize the rest of the slots to undefined.
-  __ LoadRoot(a1, Heap::kUndefinedValueRootIndex);
-  for (int i = Context::MIN_CONTEXT_SLOTS; i < length; i++) {
-    __ sw(a1, MemOperand(v0, Context::SlotOffset(i)));
-  }
-
-  // Remove the on-stack argument and return.
-  __ mov(cp, v0);
-  __ DropAndRet(1);
-
-  // Need to collect. Call into runtime system.
-  __ bind(&gc);
-  __ TailCallRuntime(Runtime::kNewFunctionContext, 1, 1);
-}
-
-
 void FastNewBlockContextStub::Generate(MacroAssembler* masm) {
   // Stack layout on entry:
   //

src/mips/full-codegen-mips.cc

@@ -211,20 +211,22 @@ void FullCodeGenerator::Generate() {
   if (heap_slots > 0) {
     Comment cmnt(masm_, "[ Allocate context");
     // Argument to NewContext is the function, which is still in a1.
-    __ push(a1);
     if (FLAG_harmony_scoping && info->scope()->is_global_scope()) {
+      __ push(a1);
       __ Push(info->scope()->GetScopeInfo());
       __ CallRuntime(Runtime::kNewGlobalContext, 2);
     } else if (heap_slots <= FastNewContextStub::kMaximumSlots) {
       FastNewContextStub stub(heap_slots);
       __ CallStub(&stub);
     } else {
+      __ push(a1);
       __ CallRuntime(Runtime::kNewFunctionContext, 1);
     }
     function_in_register = false;
-    // Context is returned in both v0 and cp.  It replaces the context
-    // passed to us.  It's saved in the stack and kept live in cp.
-    __ sw(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
+    // Context is returned in v0. It replaces the context passed to us.
+    // It's saved in the stack and kept live in cp.
+    __ mov(cp, v0);
+    __ sw(v0, MemOperand(fp, StandardFrameConstants::kContextOffset));
     // Copy any necessary parameters into the context.
     int num_parameters = info->scope()->num_parameters();
     for (int i = 0; i < num_parameters; i++) {

src/mips/lithium-codegen-mips.cc

@@ -204,17 +204,18 @@ bool LCodeGen::GeneratePrologue() {
   if (heap_slots > 0) {
     Comment(";;; Allocate local context");
     // Argument to NewContext is the function, which is in a1.
-    __ push(a1);
     if (heap_slots <= FastNewContextStub::kMaximumSlots) {
       FastNewContextStub stub(heap_slots);
       __ CallStub(&stub);
     } else {
+      __ push(a1);
       __ CallRuntime(Runtime::kNewFunctionContext, 1);
     }
     RecordSafepoint(Safepoint::kNoLazyDeopt);
-    // Context is returned in both v0 and cp.  It replaces the context
-    // passed to us.  It's saved in the stack and kept live in cp.
-    __ sw(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
+    // Context is returned in both v0. It replaces the context passed to us.
+    // It's saved in the stack and kept live in cp.
+    __ mov(cp, v0);
+    __ sw(v0, MemOperand(fp, StandardFrameConstants::kContextOffset));
     // Copy any necessary parameters into the context.
     int num_parameters = scope()->num_parameters();
     for (int i = 0; i < num_parameters; i++) {