[stubs] Split ToNumberStub into reusable subparts.

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index 1eb9379580dd0072b72116c9968ec566ced78aed..620f84c6b3ac14f0d3e9f29ed52da9d41f50e7f1 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -2572,23 +2572,21 @@ void ToNumberStub::Generate(MacroAssembler* masm) {
   __ Ret();
   __ bind(&not_heap_number);
 
-  Label not_string, slow_string;
+  NonNumberToNumberStub stub(masm->isolate());
+  __ TailCallStub(&stub);
+}
+
+void NonNumberToNumberStub::Generate(MacroAssembler* masm) {
+  // The NonNumberToNumber stub takes one argument in rax.
+  __ AssertNotNumber(rax);
+
+  Label not_string;
   __ CmpObjectType(rax, FIRST_NONSTRING_TYPE, rdi);
   // rax: object
   // rdi: object map
   __ j(above_equal, &not_string, Label::kNear);
-  // Check if string has a cached array index.
-  __ testl(FieldOperand(rax, String::kHashFieldOffset),
-           Immediate(String::kContainsCachedArrayIndexMask));
-  __ j(not_zero, &slow_string, Label::kNear);
-  __ movl(rax, FieldOperand(rax, String::kHashFieldOffset));
-  __ IndexFromHash(rax, rax);
-  __ Ret();
-  __ bind(&slow_string);
-  __ PopReturnAddressTo(rcx);     // Pop return address.
-  __ Push(rax);                   // Push argument.
-  __ PushReturnAddressFrom(rcx);  // Push return address.
-  __ TailCallRuntime(Runtime::kStringToNumber);
+  StringToNumberStub stub(masm->isolate());
+  __ TailCallStub(&stub);
   __ bind(&not_string);
 
   Label not_oddball;
@@ -2604,6 +2602,25 @@ void ToNumberStub::Generate(MacroAssembler* masm) {
   __ TailCallRuntime(Runtime::kToNumber);
 }
 
+void StringToNumberStub::Generate(MacroAssembler* masm) {
+  // The StringToNumber stub takes one argument in rax.
+  __ AssertString(rax);
+
+  // Check if string has a cached array index.
+  Label runtime;
+  __ testl(FieldOperand(rax, String::kHashFieldOffset),
+           Immediate(String::kContainsCachedArrayIndexMask));
+  __ j(not_zero, &runtime, Label::kNear);
+  __ movl(rax, FieldOperand(rax, String::kHashFieldOffset));
+  __ IndexFromHash(rax, rax);
+  __ Ret();
+
+  __ bind(&runtime);
+  __ PopReturnAddressTo(rcx);     // Pop return address.
+  __ Push(rax);                   // Push argument.
+  __ PushReturnAddressFrom(rcx);  // Push return address.
+  __ TailCallRuntime(Runtime::kStringToNumber);
+}
 
 void ToLengthStub::Generate(MacroAssembler* masm) {
   // The ToLength stub takes on argument in rax.