[compiler] Introduce StringEqualStub and StringNotEqualStub.

src/crankshaft/mips64/lithium-codegen-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.
 
 #include "src/crankshaft/mips64/lithium-codegen-mips64.h"
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/crankshaft/hydrogen-osr.h"
 #include "src/crankshaft/mips64/lithium-gap-resolver-mips64.h"
@@ skipping 2374 matching lines @@
       return kNoCondition;
   }
 }
 
 
 void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
   DCHECK(ToRegister(instr->context()).is(cp));
   DCHECK(ToRegister(instr->left()).is(a1));
   DCHECK(ToRegister(instr->right()).is(a0));
 
-  Handle<Code> code = CodeFactory::StringCompare(isolate()).code();
-  CallCode(code, RelocInfo::CODE_TARGET, instr);
+  if (Token::IsOrderedRelationalCompareOp(instr->op())) {
+    Handle<Code> code = CodeFactory::StringCompare(isolate()).code();
+    CallCode(code, RelocInfo::CODE_TARGET, instr);
 
-  EmitBranch(instr, ComputeCompareCondition(instr->op()), v0,
-             Operand(zero_reg));
+    EmitBranch(instr, ComputeCompareCondition(instr->op()), v0,
+               Operand(zero_reg));
+  } else {
+    Handle<Code> code = CodeFactory::StringEqual(isolate()).code();
+    CallCode(code, RelocInfo::CODE_TARGET, instr);
+    __ LoadRoot(at, Heap::kTrueValueRootIndex);
+
+    EmitBranch(instr, ComputeCompareCondition(instr->op()), v0, Operand(at));
+  }
 }
 
 
 static InstanceType TestType(HHasInstanceTypeAndBranch* instr) {
   InstanceType from = instr->from();
   InstanceType to = instr->to();
   if (from == FIRST_TYPE) return to;
   DCHECK(from == to || to == LAST_TYPE);
   return from;
 }
@@ skipping 3283 matching lines @@
 void LCodeGen::DoStoreFrameContext(LStoreFrameContext* instr) {
   Register context = ToRegister(instr->context());
   __ sd(context, MemOperand(fp, StandardFrameConstants::kContextOffset));
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8