[turbofan] Add typing rules for the typeof 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/base/lazy-instance.h"
 #include "src/bootstrapper.h"
 #include "src/compiler/graph-reducer.h"
@@ skipping 313 matching lines @@
   static Type* JSDivideRanger(Type::RangeType*, Type::RangeType*, Typer*);
   static Type* JSModulusRanger(Type::RangeType*, Type::RangeType*, Typer*);
 
   static ComparisonOutcome JSCompareTyper(Type*, Type*, Typer*);
 
 #define DECLARE_METHOD(x) static Type* x##Typer(Type*, Type*, Typer*);
   JS_SIMPLE_BINOP_LIST(DECLARE_METHOD)
 #undef DECLARE_METHOD
 
   static Type* JSUnaryNotTyper(Type*, Typer*);
+  static Type* JSTypeOfTyper(Type*, Typer*);
   static Type* JSLoadPropertyTyper(Type*, Type*, Typer*);
   static Type* JSCallFunctionTyper(Type*, Typer*);
 
   Reduction UpdateBounds(Node* node, Bounds current) {
     if (NodeProperties::IsTyped(node)) {
       // Widen the bounds of a previously typed node.
       Bounds previous = NodeProperties::GetBounds(node);
       if (node->opcode() == IrOpcode::kPhi) {
         // Speed up termination in the presence of range types:
         current.upper = Weaken(node, current.upper, previous.upper);
@@ skipping 860 matching lines @@
 Type* Typer::Visitor::JSUnaryNotTyper(Type* type, Typer* t) {
   return Invert(ToBoolean(type, t), t);
 }
 
 
 Bounds Typer::Visitor::TypeJSUnaryNot(Node* node) {
   return TypeUnaryOp(node, JSUnaryNotTyper);
 }
 
 
+Type* Typer::Visitor::JSTypeOfTyper(Type* type, Typer* t) {
+  Factory* const f = t->isolate()->factory();
+  if (type->Is(Type::Boolean())) {
+    return Type::Constant(f->boolean_string(), t->zone());
+  } else if (type->Is(Type::Number())) {
+    return Type::Constant(f->number_string(), t->zone());
+  } else if (type->Is(Type::Symbol())) {
+    return Type::Constant(f->symbol_string(), t->zone());
+  } else if (type->Is(Type::Union(Type::Undefined(), Type::Undetectable()))) {
+    return Type::Constant(f->undefined_string(), t->zone());
+  } else if (type->Is(Type::Null())) {
+    return Type::Constant(f->object_string(), t->zone());
+  }
+  return Type::InternalizedString();
+}
+
+
 Bounds Typer::Visitor::TypeJSTypeOf(Node* node) {
-  return Bounds(Type::None(zone()), Type::InternalizedString(zone()));
+  return TypeUnaryOp(node, JSTypeOfTyper);
 }
 
 
 // JS conversion operators.
 
 
 Bounds Typer::Visitor::TypeJSToBoolean(Node* node) {
   return TypeUnaryOp(node, ToBoolean);
 }
 
@@ skipping 1145 matching lines @@
       TYPED_ARRAYS(TYPED_ARRAY_CASE)
 #undef TYPED_ARRAY_CASE
     }
   }
   return Type::Constant(value, zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8