MIPS: Turn the NumberToStringStub into a hydrogen stub.

Port r16910 (5a0dd952)

Original commit message:
This adds a BuildLookupNumberStringCache() in Hydrogen, which will
be used by the hydrogen version of StringAddStub, in addition to the
hydrogen version of NumberToStringStub.

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/24436004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16926 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/code-stubs-mips.cc

@@ -60,6 +60,16 @@ void ToNumberStub::InitializeInterfaceDescriptor(
 }
 
 
+void NumberToStringStub::InitializeInterfaceDescriptor(
+    Isolate* isolate,
+    CodeStubInterfaceDescriptor* descriptor) {
+  static Register registers[] = { a0 };
+  descriptor->register_param_count_ = 1;
+  descriptor->register_params_ = registers;
+  descriptor->deoptimization_handler_ = NULL;
+}
+
+
 void FastCloneShallowArrayStub::InitializeInterfaceDescriptor(
     Isolate* isolate,
     CodeStubInterfaceDescriptor* descriptor) {
@@ -994,21 +1004,6 @@ static void EmitCheckForInternalizedStringsOrObjects(MacroAssembler* masm,
 }
 
 
-void NumberToStringStub::Generate(MacroAssembler* masm) {
-  Label runtime;
-
-  __ lw(a1, MemOperand(sp, 0));
-
-  // Generate code to lookup number in the number string cache.
-  __ LookupNumberStringCache(a1, v0, a2, a3, t0, &runtime);
-  __ DropAndRet(1);
-
-  __ bind(&runtime);
-  // Handle number to string in the runtime system if not found in the cache.
-  __ TailCallRuntime(Runtime::kNumberToString, 1, 1);
-}
-
-
 static void ICCompareStub_CheckInputType(MacroAssembler* masm,
                                          Register input,
                                          Register scratch,

src/mips/code-stubs-mips.h

@@ -268,18 +268,6 @@ class WriteInt32ToHeapNumberStub : public PlatformCodeStub {
 };
 
 
-class NumberToStringStub: public PlatformCodeStub {
- public:
-  NumberToStringStub() { }
-
- private:
-  Major MajorKey() { return NumberToString; }
-  int MinorKey() { return 0; }
-
-  void Generate(MacroAssembler* masm);
-};
-
-
 class RecordWriteStub: public PlatformCodeStub {
  public:
   RecordWriteStub(Register object,

src/mips/full-codegen-mips.cc

@@ -3611,8 +3611,9 @@ void FullCodeGenerator::EmitNumberToString(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   ASSERT_EQ(args->length(), 1);
 
-  // Load the argument on the stack and call the stub.
-  VisitForStackValue(args->at(0));
+  // Load the argument into a0 and call the stub.
+  VisitForAccumulatorValue(args->at(0));
+  __ mov(a0, result_register());
 
   NumberToStringStub stub;
   __ CallStub(&stub);

src/mips/lithium-codegen-mips.cc

@@ -1063,11 +1063,6 @@ void LCodeGen::DoCallStub(LCallStub* instr) {
       CallCode(stub.GetCode(isolate()), RelocInfo::CODE_TARGET, instr);
       break;
     }
-    case CodeStub::NumberToString: {
-      NumberToStringStub stub;
-      CallCode(stub.GetCode(isolate()), RelocInfo::CODE_TARGET, instr);
-      break;
-    }
     case CodeStub::StringCompare: {
       StringCompareStub stub;
       CallCode(stub.GetCode(isolate()), RelocInfo::CODE_TARGET, instr);