[stubs] replaced ToString MacroAssembler Stub with CodeStubAssembler builtin

src/mips64/code-stubs-mips64.cc

Index: src/mips64/code-stubs-mips64.cc
diff --git a/src/mips64/code-stubs-mips64.cc b/src/mips64/code-stubs-mips64.cc
index c0c05747df22f643df78c0eb8509c04fc9fd3646..d1756d0103921872de56b690c94ce32354938f9f 100644
--- a/src/mips64/code-stubs-mips64.cc
+++ b/src/mips64/code-stubs-mips64.cc
@@ -2494,37 +2494,6 @@ void SubStringStub::Generate(MacroAssembler* masm) {
   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,