X87: [runtime] Add %ToString and %_ToString and remove the TO_STRING builtin.

src/x87/code-stubs-x87.cc

Index: src/x87/code-stubs-x87.cc
diff --git a/src/x87/code-stubs-x87.cc b/src/x87/code-stubs-x87.cc
index ff05f4d763af4032802c1d7977e29d4841152534..ea6250fae188eef717390507cf71d735bbf8dbf6 100644
--- a/src/x87/code-stubs-x87.cc
+++ b/src/x87/code-stubs-x87.cc
@@ -2985,6 +2985,41 @@ void ToNumberStub::Generate(MacroAssembler* masm) {
 }
 
 
+void ToStringStub::Generate(MacroAssembler* masm) {
+  // The ToString stub takes one argument in eax.
+  Label is_number;
+  __ JumpIfSmi(eax, &is_number, Label::kNear);
+
+  Label not_string;
+  __ CmpObjectType(eax, FIRST_NONSTRING_TYPE, edi);
+  // eax: receiver
+  // edi: receiver map
+  __ j(above_equal, &not_string, Label::kNear);
+  __ Ret();
+  __ bind(&not_string);
+
+  Label not_heap_number;
+  __ CompareMap(eax, masm->isolate()->factory()->heap_number_map());
+  __ j(not_equal, &not_heap_number, Label::kNear);
+  __ bind(&is_number);
+  NumberToStringStub stub(isolate());
+  __ TailCallStub(&stub);
+  __ bind(&not_heap_number);
+
+  Label not_oddball;
+  __ CmpInstanceType(edi, ODDBALL_TYPE);
+  __ j(not_equal, &not_oddball, Label::kNear);
+  __ mov(eax, FieldOperand(eax, Oddball::kToStringOffset));
+  __ Ret();
+  __ bind(&not_oddball);
+
+  __ pop(ecx);   // Pop return address.
+  __ push(eax);  // Push argument.
+  __ push(ecx);  // Push return address.
+  __ TailCallRuntime(Runtime::kToString, 1, 1);
+}
+
+
 void StringHelper::GenerateFlatOneByteStringEquals(MacroAssembler* masm,
                                                    Register left,
                                                    Register right,