Get rid of HStringLength.

src/hydrogen-instructions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 160 matching lines @@
   V(StoreGlobalCell)                           \
   V(StoreGlobalGeneric)                        \
   V(StoreKeyed)                                \
   V(StoreKeyedGeneric)                         \
   V(StoreNamedField)                           \
   V(StoreNamedGeneric)                         \
   V(StringAdd)                                 \
   V(StringCharCodeAt)                          \
   V(StringCharFromCode)                        \
   V(StringCompareAndBranch)                    \
-  V(StringLength)                              \
   V(Sub)                                       \
   V(ThisFunction)                              \
   V(Throw)                                     \
   V(ToFastProperties)                          \
   V(TransitionElementsKind)                    \
   V(TrapAllocationMemento)                     \
   V(Typeof)                                    \
   V(TypeofIsAndBranch)                         \
   V(UnaryMathOperation)                        \
   V(UnknownOSRValue)                           \
   V(UseConst)                                  \
   V(ValueOf)                                   \
   V(WrapReceiver)
 
 #define GVN_TRACKED_FLAG_LIST(V)               \
   V(Maps)                                      \
   V(NewSpacePromotion)
 
 #define GVN_UNTRACKED_FLAG_LIST(V)             \
   V(ArrayElements)                             \
   V(ArrayLengths)                              \
+  V(StringLengths)                             \
   V(BackingStoreFields)                        \
   V(Calls)                                     \
   V(ContextSlots)                              \
   V(DoubleArrayElements)                       \
   V(DoubleFields)                              \
   V(ElementsKind)                              \
   V(ElementsPointer)                           \
   V(GlobalVars)                                \
   V(InobjectFields)                            \
   V(OsrEntries)                                \
@@ skipping 5625 matching lines @@
 class HObjectAccess {
  public:
   inline bool IsInobject() const {
     return portion() != kBackingStore && portion() != kExternalMemory;
   }
 
   inline bool IsExternalMemory() const {
     return portion() == kExternalMemory;
   }
 
+  inline bool IsStringLength() const {
+    return portion() == kStringLengths;
+  }
+
   inline int offset() const {
     return OffsetField::decode(value_);
   }
 
   inline Representation representation() const {
     return Representation::FromKind(RepresentationField::decode(value_));
   }
 
   inline Handle<String> name() const {
     return name_;
@@ skipping 33 matching lines @@
     return HObjectAccess(kExternalMemory, 0, Representation::Tagged());
   }
 
   static HObjectAccess ForFixedArrayLength() {
     return HObjectAccess(
         kArrayLengths,
         FixedArray::kLengthOffset,
         FLAG_track_fields ? Representation::Smi() : Representation::Tagged());
   }
 
+  static HObjectAccess ForStringLength() {
+    STATIC_ASSERT(String::kMaxLength <= Smi::kMaxValue);
+    return HObjectAccess(
+        kStringLengths,
+        String::kLengthOffset,
+        FLAG_track_fields ? Representation::Smi() : Representation::Tagged());
+  }
+
   static HObjectAccess ForPropertiesPointer() {
     return HObjectAccess(kInobject, JSObject::kPropertiesOffset);
   }
 
   static HObjectAccess ForPrototypeOrInitialMap() {
     return HObjectAccess(kInobject, JSFunction::kPrototypeOrInitialMapOffset);
   }
 
   static HObjectAccess ForMap() {
     return HObjectAccess(kMaps, JSObject::kMapOffset);
@@ skipping 43 matching lines @@
   }
 
  protected:
   void SetGVNFlags(HValue *instr, bool is_store);
 
  private:
   // internal use only; different parts of an object or array
   enum Portion {
     kMaps,             // map of an object
     kArrayLengths,     // the length of an array
+    kStringLengths,    // the length of a string
     kElementsPointer,  // elements pointer
     kBackingStore,     // some field in the backing store
     kDouble,           // some double field
     kInobject,         // some other in-object field
     kExternalMemory    // some field in external memory
   };
 
   HObjectAccess(Portion portion, int offset,
                 Representation representation = Representation::Tagged(),
                 Handle<String> name = Handle<String>::null())
@@ skipping 42 matching lines @@
   }
 
   virtual bool HasEscapingOperandAt(int index) { return false; }
   virtual Representation RequiredInputRepresentation(int index) {
     if (index == 0 && access().IsExternalMemory()) {
       // object must be external in case of external memory access
       return Representation::External();
     }
     return Representation::Tagged();
   }
+  virtual Range* InferRange(Zone* zone);
   virtual void PrintDataTo(StringStream* stream);
 
   DECLARE_CONCRETE_INSTRUCTION(LoadNamedField)
 
  protected:
   virtual bool DataEquals(HValue* other) {
     HLoadNamedField* b = HLoadNamedField::cast(other);
     return access_.Equals(b->access_);
   }
 
@@ skipping 815 matching lines @@
     SetFlag(kUseGVN);
     SetGVNFlag(kChangesNewSpacePromotion);
   }
 
   virtual bool IsDeletable() const {
     return !value()->ToNumberCanBeObserved();
   }
 };
 
 
-class HStringLength: public HUnaryOperation {
- public:
-  static HInstruction* New(Zone* zone, HValue* context, HValue* string);
-
-  virtual Representation RequiredInputRepresentation(int index) {
-    return Representation::Tagged();
-  }
-
-  DECLARE_CONCRETE_INSTRUCTION(StringLength)
-
- protected:
-  virtual bool DataEquals(HValue* other) { return true; }
-
-  virtual Range* InferRange(Zone* zone) {
-    return new(zone) Range(0, String::kMaxLength);
-  }
-
- private:
-  explicit HStringLength(HValue* string)
-      : HUnaryOperation(string, HType::Smi()) {
-    STATIC_ASSERT(String::kMaxLength <= Smi::kMaxValue);
-    set_representation(Representation::Tagged());
-    SetFlag(kUseGVN);
-    SetGVNFlag(kDependsOnMaps);
-  }
-
-  virtual bool IsDeletable() const { return true; }
-};
-
-
 template <int V>
 class HMaterializedLiteral: public HTemplateInstruction<V> {
  public:
   HMaterializedLiteral<V>(int index, int depth, AllocationSiteMode mode)
       : literal_index_(index), depth_(depth), allocation_site_mode_(mode) {
     this->set_representation(Representation::Tagged());
   }
 
   HMaterializedLiteral<V>(int index, int depth)
       : literal_index_(index), depth_(depth),
@@ skipping 369 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_