MIPS: Add HLoadRoot hydrogen instruction.

Port r16807 (257f48f)

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/24134004

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

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16840 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/lithium-codegen-mips.cc

@@ -3002,6 +3002,12 @@ void LCodeGen::DoLoadFunctionPrototype(LLoadFunctionPrototype* instr) {
 }
 
 
+void LCodeGen::DoLoadRoot(LLoadRoot* instr) {
+  Register result = ToRegister(instr->result());
+  __ LoadRoot(result, instr->index());
+}
+
+
 void LCodeGen::DoLoadExternalArrayPointer(
     LLoadExternalArrayPointer* instr) {
   Register to_reg = ToRegister(instr->result());

src/mips/lithium-mips.cc

@@ -2071,6 +2071,11 @@ LInstruction* LChunkBuilder::DoLoadFunctionPrototype(
 }
 
 
+LInstruction* LChunkBuilder::DoLoadRoot(HLoadRoot* instr) {
+  return DefineAsRegister(new(zone()) LLoadRoot);
+}
+
+
 LInstruction* LChunkBuilder::DoLoadExternalArrayPointer(
     HLoadExternalArrayPointer* instr) {
   LOperand* input = UseRegisterAtStart(instr->value());

src/mips/lithium-mips.h

@@ -119,6 +119,7 @@ class LCodeGen;
   V(LazyBailout)                                \
   V(LoadContextSlot)                            \
   V(LoadExternalArrayPointer)                   \
+  V(LoadRoot)                                   \
   V(LoadFieldByIndex)                           \
   V(LoadFunctionPrototype)                      \
   V(LoadGlobalCell)                             \
@@ -1559,6 +1560,15 @@ class LLoadFunctionPrototype V8_FINAL : public LTemplateInstruction<1, 1, 0> {
 };
 
 
+class LLoadRoot V8_FINAL : public LTemplateInstruction<1, 0, 0> {
+ public:
+  DECLARE_CONCRETE_INSTRUCTION(LoadRoot, "load-root")
+  DECLARE_HYDROGEN_ACCESSOR(LoadRoot)
+
+  Heap::RootListIndex index() const { return hydrogen()->index(); }
+};
+
+
 class LLoadExternalArrayPointer V8_FINAL
     : public LTemplateInstruction<1, 1, 0> {
  public: