[stubs] Split ToNumberStub into reusable subparts.

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 3f1c8708ad4e9230a7dac684270d33aab514674f..bd83cd1ae8cdfdfc4f15e02292025f115366e1a7 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -2661,29 +2661,28 @@ void SubStringStub::Generate(MacroAssembler* masm) {
 
 void ToNumberStub::Generate(MacroAssembler* masm) {
   // The ToNumber stub takes one argument in r0.
-  Label not_smi;
-  __ JumpIfNotSmi(r0, &not_smi);
-  __ Ret();
-  __ bind(&not_smi);
+  STATIC_ASSERT(kSmiTag == 0);
+  __ tst(r0, Operand(kSmiTagMask));
+  __ Ret(eq);
 
   __ CompareObjectType(r0, r1, r1, HEAP_NUMBER_TYPE);
   // r0: receiver
   // r1: receiver instance type
   __ Ret(eq);
 
-  Label not_string, slow_string;
-  __ cmp(r1, Operand(FIRST_NONSTRING_TYPE));
-  __ b(hs, &not_string);
-  // Check if string has a cached array index.
-  __ ldr(r2, FieldMemOperand(r0, String::kHashFieldOffset));
-  __ tst(r2, Operand(String::kContainsCachedArrayIndexMask));
-  __ b(ne, &slow_string);
-  __ IndexFromHash(r2, r0);
-  __ Ret();
-  __ bind(&slow_string);
-  __ push(r0);  // Push argument.
-  __ TailCallRuntime(Runtime::kStringToNumber);
-  __ bind(&not_string);
+  NonNumberToNumberStub stub(masm->isolate());
+  __ TailCallStub(&stub);
+}
+
+void NonNumberToNumberStub::Generate(MacroAssembler* masm) {
+  // The NonNumberToNumber stub takes one argument in r0.
+  __ AssertNotNumber(r0);
+
+  __ CompareObjectType(r0, r1, r1, FIRST_NONSTRING_TYPE);
+  // r0: receiver
+  // r1: receiver instance type
+  StringToNumberStub stub(masm->isolate());
+  __ TailCallStub(&stub, lo);
 
   Label not_oddball;
   __ cmp(r1, Operand(ODDBALL_TYPE));
@@ -2692,10 +2691,26 @@ void ToNumberStub::Generate(MacroAssembler* masm) {
   __ Ret();
   __ bind(&not_oddball);
 
-  __ push(r0);  // Push argument.
+  __ Push(r0);  // Push argument.
   __ TailCallRuntime(Runtime::kToNumber);
 }
 
+void StringToNumberStub::Generate(MacroAssembler* masm) {
+  // The StringToNumber stub takes one argument in r0.
+  __ AssertString(r0);
+
+  // Check if string has a cached array index.
+  Label runtime;
+  __ ldr(r2, FieldMemOperand(r0, String::kHashFieldOffset));
+  __ tst(r2, Operand(String::kContainsCachedArrayIndexMask));
+  __ b(ne, &runtime);
+  __ IndexFromHash(r2, r0);
+  __ Ret();
+
+  __ bind(&runtime);
+  __ Push(r0);  // Push argument.
+  __ TailCallRuntime(Runtime::kStringToNumber);
+}
 
 void ToLengthStub::Generate(MacroAssembler* masm) {
   // The ToLength stub takes one argument in r0.