[compiler] Introduce code stubs for string relational comparisons.

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/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
 #include "src/ic/handler-compiler.h"
@@ skipping 2799 matching lines @@
   Label loop;
   __ bind(&loop);
   __ movb(scratch, Operand(left, index, times_1, 0));
   __ cmpb(scratch, Operand(right, index, times_1, 0));
   __ j(not_equal, chars_not_equal, near_jump);
   __ incq(index);
   __ j(not_zero, &loop);
 }
 
 
-void StringCompareStub::Generate(MacroAssembler* masm) {
-  // ----------- S t a t e -------------
-  //  -- rdx    : left string
-  //  -- rax    : right string
-  //  -- rsp[0] : return address
-  // -----------------------------------
-  __ AssertString(rdx);
-  __ AssertString(rax);
-
-  // Check for identity.
-  Label not_same;
-  __ cmpp(rdx, rax);
-  __ j(not_equal, &not_same, Label::kNear);
-  __ Move(rax, Smi::FromInt(EQUAL));
-  __ IncrementCounter(isolate()->counters()->string_compare_native(), 1);
-  __ Ret();
-
-  __ bind(&not_same);
-
-  // Check that both are sequential one-byte strings.
-  Label runtime;
-  __ JumpIfNotBothSequentialOneByteStrings(rdx, rax, rcx, rbx, &runtime);
-
-  // Inline comparison of one-byte strings.
-  __ IncrementCounter(isolate()->counters()->string_compare_native(), 1);
-  StringHelper::GenerateCompareFlatOneByteStrings(masm, rdx, rax, rcx, rbx, rdi,
-                                                  r8);
-
-  // Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
-  // tagged as a small integer.
-  __ bind(&runtime);
-  __ PopReturnAddressTo(rcx);
-  __ Push(rdx);
-  __ Push(rax);
-  __ PushReturnAddressFrom(rcx);
-  __ TailCallRuntime(Runtime::kStringCompare);
-}
-
-
 void BinaryOpICWithAllocationSiteStub::Generate(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rdx    : left
   //  -- rax    : right
   //  -- rsp[0] : return address
   // -----------------------------------
 
   // Load rcx with the allocation site.  We stick an undefined dummy value here
   // and replace it with the real allocation site later when we instantiate this
   // stub in BinaryOpICWithAllocationSiteStub::GetCodeCopyFromTemplate().
@@ skipping 2782 matching lines @@
                            NULL);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64