Introduce FieldIndex to unify and abstract property/field offset

src/code-stubs.h

 // 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.
 
 #ifndef V8_CODE_STUBS_H_
 #define V8_CODE_STUBS_H_
 
 #include "src/allocation.h"
 #include "src/assembler.h"
 #include "src/codegen.h"
@@ skipping 879 matching lines @@
 
  protected:
   explicit HandlerStub(Isolate* isolate) : HICStub(isolate) { }
   virtual int NotMissMinorKey() { return bit_field_; }
   int bit_field_;
 };
 
 
 class LoadFieldStub: public HandlerStub {
  public:
-  LoadFieldStub(Isolate* isolate,
-                bool inobject,
-                int index, Representation representation)
-      : HandlerStub(isolate) {
-    Initialize(Code::LOAD_IC, inobject, index, representation);
+  LoadFieldStub(Isolate* isolate, FieldIndex index)
+    : HandlerStub(isolate), index_(index) {
+    Initialize(Code::LOAD_IC);
   }
 
   virtual Handle<Code> GenerateCode() V8_OVERRIDE;
 
   virtual void InitializeInterfaceDescriptor(
       CodeStubInterfaceDescriptor* descriptor) V8_OVERRIDE;
 
   Representation representation() {
     if (unboxed_double()) return Representation::Double();
     return Representation::Tagged();
   }
 
   virtual Code::Kind kind() const {
     return KindBits::decode(bit_field_);
   }
 
-  bool is_inobject() {
-    return InobjectBits::decode(bit_field_);
-  }
-
-  int offset() {
-    int index = IndexBits::decode(bit_field_);
-    int offset = index * kPointerSize;
-    if (is_inobject()) return offset;
-    return FixedArray::kHeaderSize + offset;
-  }
+  FieldIndex index() const { return index_; }
 
   bool unboxed_double() {
-    return UnboxedDoubleBits::decode(bit_field_);
+    return index_.is_double();
   }
 
   virtual Code::StubType GetStubType() { return Code::FAST; }
 
  protected:
-  explicit LoadFieldStub(Isolate* isolate) : HandlerStub(isolate) { }
+  explicit LoadFieldStub(Isolate* isolate);
 
-  void Initialize(Code::Kind kind,
-                  bool inobject,
-                  int index,
-                  Representation representation) {
-    bit_field_ = KindBits::encode(kind)
-        | InobjectBits::encode(inobject)
-        | IndexBits::encode(index)
-        | UnboxedDoubleBits::encode(representation.IsDouble());
+  void Initialize(Code::Kind kind) {
+    int property_index_key = index_.GetLoadFieldStubKey();
+    // Save a copy of the essence of the property index into the bit field to
+    // make sure that hashing of unique stubs works correctly..
+    bit_field_ = KindBits::encode(kind) |
+        EncodedLoadFieldByIndexBits::encode(property_index_key);
   }
 
  private:
   STATIC_ASSERT(KindBits::kSize == 4);
-  class InobjectBits: public BitField<bool, 4, 1> {};
-  class IndexBits: public BitField<int, 5, 11> {};
-  class UnboxedDoubleBits: public BitField<bool, 16, 1> {};
+  class EncodedLoadFieldByIndexBits: public BitField<int, 4, 13> {};
   virtual CodeStub::Major MajorKey() { return LoadField; }
+  FieldIndex index_;
 };
 
 
 class StringLengthStub: public HandlerStub {
  public:
   explicit StringLengthStub(Isolate* isolate) : HandlerStub(isolate) {
     Initialize(Code::LOAD_IC);
   }
   virtual Handle<Code> GenerateCode() V8_OVERRIDE;
   virtual void InitializeInterfaceDescriptor(
@@ skipping 124 matching lines @@
   virtual void Generate(MacroAssembler* masm) V8_OVERRIDE;
   virtual Major MajorKey() V8_OVERRIDE { return CallApiGetter; }
   virtual int MinorKey() V8_OVERRIDE { return 0; }
 
   DISALLOW_COPY_AND_ASSIGN(CallApiGetterStub);
 };
 
 
 class KeyedLoadFieldStub: public LoadFieldStub {
  public:
-  KeyedLoadFieldStub(Isolate* isolate,
-                     bool inobject,
-                     int index, Representation representation)
-      : LoadFieldStub(isolate) {
-    Initialize(Code::KEYED_LOAD_IC, inobject, index, representation);
+  KeyedLoadFieldStub(Isolate* isolate, FieldIndex index)
+      : LoadFieldStub(isolate, index) {
+    Initialize(Code::KEYED_LOAD_IC);
   }
 
   virtual void InitializeInterfaceDescriptor(
       CodeStubInterfaceDescriptor* descriptor) V8_OVERRIDE;
 
  private:
   virtual CodeStub::Major MajorKey() { return KeyedLoadField; }
 };
 
 
@@ skipping 1359 matching lines @@
 
 
 class CallDescriptors {
  public:
   static void InitializeForIsolate(Isolate* isolate);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_