Replace ICStub for array.length with hydrogen stub

src/code-stubs.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 29 matching lines @@
   V(CallFunction)                        \
   V(CallConstruct)                       \
   V(UnaryOp)                             \
   V(BinaryOp)                            \
   V(StringAdd)                           \
   V(SubString)                           \
   V(StringCompare)                       \
   V(Compare)                             \
   V(CompareIC)                           \
   V(MathPow)                             \
-  V(ArrayLength)                         \
+  V(FastArrayLength)                     \
   V(StringLength)                        \
   V(FunctionPrototype)                   \
   V(StoreArrayLength)                    \
   V(RecordWrite)                         \
   V(StoreBufferOverflow)                 \
   V(RegExpExec)                          \
   V(TranscendentalCache)                 \
   V(Instanceof)                          \
   V(ConvertToDouble)                     \
   V(WriteInt32ToHeapNumber)              \
@@ skipping 529 matching lines @@
 
   virtual int MinorKey() {
     return KindBits::encode(kind_);
   }
 
  private:
   Code::Kind kind_;
 };
 
 
-class ArrayLengthStub: public ICStub {
+class FastArrayLengthStub: public HydrogenCodeStub {
  public:
-  explicit ArrayLengthStub(Code::Kind kind) : ICStub(kind) { }
-  virtual void Generate(MacroAssembler* masm);
+  explicit FastArrayLengthStub(Register receiver) : receiver_(receiver) { }
+
+  virtual Handle<Code> GenerateCode();
+
+  virtual void InitializeInterfaceDescriptor(
+      Isolate* isolate,
+      CodeStubInterfaceDescriptor* descriptor);
+
+ protected:
+  virtual void FinishCode(Handle<Code> code) {
+    Code::Flags flags = code->flags();
+    flags = static_cast<Code::Flags>(
+        Code::TypeField::update(flags, Code::CALLBACKS));
+    flags = static_cast<Code::Flags>(
+        Code::ICStateField::update(flags, MONOMORPHIC));
+    code->set_flags(flags);
+  }

[Dmitry Lomov (no reviews), 2013/03/11 17:31:31]

Not entirely happy about this code; probably need to parametrize
HydrogenCodeStub with this 

[danno, 2013/03/12 11:16:16]

Agreed. You shouldn't have to override FinishCode here.
On 2013/03/11 17:31:31, Dmitry Lomov (chromium) wrote:

+
+  virtual Code::StubType GetStubType() {
+    return Code::CALLBACKS;
+  }
 
  private:
-  virtual CodeStub::Major MajorKey() { return ArrayLength; }
+  virtual CodeStub::Major MajorKey() { return FastArrayLength; }
+  virtual int MinorKey() { return 0; }
+
+  Register receiver_;
+  // Initialized in InititalizeInterfaceDescriptor
+  Register registers_[2];
+
+  DISALLOW_COPY_AND_ASSIGN(FastArrayLengthStub);
 };
 
 
 class FunctionPrototypeStub: public ICStub {
  public:
   explicit FunctionPrototypeStub(Code::Kind kind) : ICStub(kind) { }
   virtual void Generate(MacroAssembler* masm);
 
  private:
   virtual CodeStub::Major MajorKey() { return FunctionPrototype; }
@@ skipping 1002 matching lines @@
 
   // The current function entry hook.
   static FunctionEntryHook entry_hook_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileEntryHookStub);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_