[turbofan] Introduce ObjectIsString operator.

src/compiler/typer.cc

 // Copyright 2014 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/compiler/typer.h"
 
 #include "src/base/flags.h"
 #include "src/bootstrapper.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/common-operator.h"
@@ skipping 232 matching lines @@
   static Type* NumberCeil(Type*, Typer*);
   static Type* NumberFloor(Type*, Typer*);
   static Type* NumberRound(Type*, Typer*);
   static Type* NumberTrunc(Type*, Typer*);
   static Type* NumberToInt32(Type*, Typer*);
   static Type* NumberToUint32(Type*, Typer*);
 
   static Type* ObjectIsNumber(Type*, Typer*);
   static Type* ObjectIsReceiver(Type*, Typer*);
   static Type* ObjectIsSmi(Type*, Typer*);
+  static Type* ObjectIsString(Type*, Typer*);
   static Type* ObjectIsUndetectable(Type*, Typer*);
 
   static Type* JSAddRanger(RangeType*, RangeType*, Typer*);
   static Type* JSSubtractRanger(RangeType*, RangeType*, Typer*);
   static Type* JSDivideRanger(RangeType*, RangeType*, Typer*);
   static Type* JSModulusRanger(RangeType*, RangeType*, Typer*);
 
   static ComparisonOutcome JSCompareTyper(Type*, Type*, Typer*);
 
 #define DECLARE_METHOD(x) static Type* x##Typer(Type*, Type*, Typer*);
@@ skipping 307 matching lines @@
   return Type::Boolean();
 }
 
 
 Type* Typer::Visitor::ObjectIsSmi(Type* type, Typer* t) {
   if (type->Is(Type::TaggedSigned())) return t->singleton_true_;
   if (type->Is(Type::TaggedPointer())) return t->singleton_false_;
   return Type::Boolean();
 }
 
+Type* Typer::Visitor::ObjectIsString(Type* type, Typer* t) {
+  if (type->Is(Type::String())) return t->singleton_true_;
+  if (!type->Maybe(Type::String())) return t->singleton_false_;
+  return Type::Boolean();
+}
 
 Type* Typer::Visitor::ObjectIsUndetectable(Type* type, Typer* t) {
   if (type->Is(Type::Undetectable())) return t->singleton_true_;
   if (!type->Maybe(Type::Undetectable())) return t->singleton_false_;
   return Type::Boolean();
 }
 
 
 // -----------------------------------------------------------------------------
 
@@ skipping 1400 matching lines @@
 
 Type* Typer::Visitor::TypeObjectIsReceiver(Node* node) {
   return TypeUnaryOp(node, ObjectIsReceiver);
 }
 
 
 Type* Typer::Visitor::TypeObjectIsSmi(Node* node) {
   return TypeUnaryOp(node, ObjectIsSmi);
 }
 
+Type* Typer::Visitor::TypeObjectIsString(Node* node) {
+  return TypeUnaryOp(node, ObjectIsString);
+}
 
 Type* Typer::Visitor::TypeObjectIsUndetectable(Node* node) {
   return TypeUnaryOp(node, ObjectIsUndetectable);
 }
 
 
 // Machine operators.
 
 Type* Typer::Visitor::TypeLoad(Node* node) { return Type::Any(); }
 
@@ skipping 526 matching lines @@
   }
   if (Type::IsInteger(*value)) {
     return Type::Range(value->Number(), value->Number(), zone());
   }
   return Type::Constant(value, zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8