[stubs] replaced ToString MacroAssembler Stub with CodeStubAssembler builtin

src/mips64/code-stubs-mips64.cc

 // Copyright 2012 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_MIPS64
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 2476 matching lines @@
   // a2: length
   // a3: from index (untagged)
   __ SmiTag(a3);
   StringCharAtGenerator generator(v0, a3, a2, v0, &runtime, &runtime, &runtime,
                                   RECEIVER_IS_STRING);
   generator.GenerateFast(masm);
   __ DropAndRet(3);
   generator.SkipSlow(masm, &runtime);
 }
 
-void ToStringStub::Generate(MacroAssembler* masm) {
-  // The ToString stub takes on argument in a0.
-  Label is_number;
-  __ JumpIfSmi(a0, &is_number);
-
-  Label not_string;
-  __ GetObjectType(a0, a1, a1);
-  // a0: receiver
-  // a1: receiver instance type
-  __ Branch(&not_string, ge, a1, Operand(FIRST_NONSTRING_TYPE));
-  __ Ret(USE_DELAY_SLOT);
-  __ mov(v0, a0);
-  __ bind(&not_string);
-
-  Label not_heap_number;
-  __ Branch(&not_heap_number, ne, a1, Operand(HEAP_NUMBER_TYPE));
-  __ bind(&is_number);
-  NumberToStringStub stub(isolate());
-  __ TailCallStub(&stub);
-  __ bind(&not_heap_number);
-
-  Label not_oddball;
-  __ Branch(&not_oddball, ne, a1, Operand(ODDBALL_TYPE));
-  __ Ret(USE_DELAY_SLOT);
-  __ ld(v0, FieldMemOperand(a0, Oddball::kToStringOffset));
-  __ bind(&not_oddball);
-
-  __ push(a0);  // Push argument.
-  __ TailCallRuntime(Runtime::kToString);
-}
-
 
 void StringHelper::GenerateFlatOneByteStringEquals(
     MacroAssembler* masm, Register left, Register right, Register scratch1,
     Register scratch2, Register scratch3) {
   Register length = scratch1;
 
   // Compare lengths.
   Label strings_not_equal, check_zero_length;
   __ ld(length, FieldMemOperand(left, String::kLengthOffset));
   __ ld(scratch2, FieldMemOperand(right, String::kLengthOffset));
@@ skipping 2853 matching lines @@
                            kStackUnwindSpace, kInvalidStackOffset,
                            return_value_operand, NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS64