Replace ICStub for array.length with hydrogen stub

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 151a51ca31d03c123035dfc7a3c789b4a358eae9..4f9a6374591d17955a0771e71244b7462df63563 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -47,7 +47,7 @@ namespace internal {
   V(Compare)                             \
   V(CompareIC)                           \
   V(MathPow)                             \
-  V(ArrayLength)                         \
+  V(FastArrayLength)                     \
   V(StringLength)                        \
   V(FunctionPrototype)                   \
   V(StoreArrayLength)                    \
@@ -597,13 +597,39 @@ class ICStub: public PlatformCodeStub {
 };
 
 
-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);
 };