[stubs] Introduce ToNameStub to implement %_ToName.

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 7f976940b5a2213e505c3af0005405d9efb1dc8b..c0113f8bdd849a1099d9e4dbcf16c62daf25c2e0 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -3075,6 +3075,42 @@ void ToStringStub::Generate(MacroAssembler* masm) {
 }
 
 
+void ToNameStub::Generate(MacroAssembler* masm) {
+  // The ToName stub takes one argument in rax.
+  Label is_number;
+  __ JumpIfSmi(rax, &is_number, Label::kNear);
+
+  Label not_name;
+  STATIC_ASSERT(FIRST_NAME_TYPE == FIRST_TYPE);
+  __ CmpObjectType(rax, LAST_NAME_TYPE, rdi);
+  // rax: receiver
+  // rdi: receiver map
+  __ j(above, &not_name, Label::kNear);
+  __ Ret();
+  __ bind(&not_name);
+
+  Label not_heap_number;
+  __ CompareRoot(rdi, Heap::kHeapNumberMapRootIndex);
+  __ j(not_equal, &not_heap_number, Label::kNear);
+  __ bind(&is_number);
+  NumberToStringStub stub(isolate());
+  __ TailCallStub(&stub);
+  __ bind(&not_heap_number);
+
+  Label not_oddball;
+  __ CmpInstanceType(rdi, ODDBALL_TYPE);
+  __ j(not_equal, &not_oddball, Label::kNear);
+  __ movp(rax, FieldOperand(rax, Oddball::kToStringOffset));
+  __ Ret();
+  __ bind(&not_oddball);
+
+  __ PopReturnAddressTo(rcx);     // Pop return address.
+  __ Push(rax);                   // Push argument.
+  __ PushReturnAddressFrom(rcx);  // Push return address.
+  __ TailCallRuntime(Runtime::kToName);
+}
+
+
 void StringHelper::GenerateFlatOneByteStringEquals(MacroAssembler* masm,
                                                    Register left,
                                                    Register right,