[stubs] replaced ToString MacroAssembler Stub with CodeStubAssembler builtin

src/x64/code-stubs-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 2214 matching lines @@
   // rbx: instance type
   // rcx: sub string length (smi)
   // rdx: from index (smi)
   StringCharAtGenerator generator(rax, rdx, rcx, rax, &runtime, &runtime,
                                   &runtime, RECEIVER_IS_STRING);
   generator.GenerateFast(masm);
   __ ret(SUB_STRING_ARGUMENT_COUNT * kPointerSize);
   generator.SkipSlow(masm, &runtime);
 }
 
-void ToStringStub::Generate(MacroAssembler* masm) {
-  // The ToString stub takes one argument in rax.
-  Label is_number;
-  __ JumpIfSmi(rax, &is_number, Label::kNear);
-
-  Label not_string;
-  __ CmpObjectType(rax, FIRST_NONSTRING_TYPE, rdi);
-  // rax: receiver
-  // rdi: receiver map
-  __ j(above_equal, &not_string, Label::kNear);
-  __ Ret();
-  __ bind(&not_string);
-
-  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::kToString);
-}
-
 
 void StringHelper::GenerateFlatOneByteStringEquals(MacroAssembler* masm,
                                                    Register left,
                                                    Register right,
                                                    Register scratch1,
                                                    Register scratch2) {
   Register length = scratch1;
 
   // Compare lengths.
   Label check_zero_length;
@@ skipping 2882 matching lines @@
                            kStackUnwindSpace, nullptr, return_value_operand,
                            NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64