Polymorphism support for load IC.

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 62 matching lines @@
   V(CEntry)                              \
   V(JSEntry)                             \
   V(KeyedLoadElement)                    \
   V(KeyedStoreElement)                   \
   V(DebuggerStatement)                   \
   V(StringDictionaryLookup)              \
   V(ElementsTransitionAndStore)          \
   V(TransitionElementsKind)              \
   V(StoreArrayLiteralElement)            \
   V(StubFailureTrampoline)               \
-  V(ProfileEntryHook)
+  V(ProfileEntryHook)                    \
+  /* IC Handler stubs */                 \
+  V(LoadField)
 
 // List of code stubs only used on ARM platforms.
 #ifdef V8_TARGET_ARCH_ARM
 #define CODE_STUB_LIST_ARM(V)  \
   V(GetProperty)               \
   V(SetProperty)               \
   V(InvokeBuiltin)             \
   V(RegExpCEntry)              \
   V(DirectCEntry)
 #else
@@ skipping 84 matching lines @@
   // Generates the assembler code for the stub.
   virtual Handle<Code> GenerateCode() = 0;
 
   // BinaryOpStub needs to override this.
   virtual InlineCacheState GetICState() {
     return UNINITIALIZED;
   }
   virtual Code::ExtraICState GetExtraICState() {
     return Code::kNoExtraICState;
   }
+  virtual Code::StubType GetStubType() {
+    return Code::NORMAL;
+  }
 
   // Returns whether the code generated for this stub needs to be allocated as
   // a fixed (non-moveable) code object.
   virtual bool NeedsImmovableCode() { return false; }
 
  private:
   // Perform bookkeeping required after code generation when stub code is
   // initially generated.
   void RecordCodeGeneration(Code* code, Isolate* isolate);
 
@@ skipping 444 matching lines @@
  public:
   explicit StoreArrayLengthStub(Code::Kind kind, StrictModeFlag strict_mode)
       : StoreICStub(kind, strict_mode) { }
   virtual void Generate(MacroAssembler* masm);
 
  private:
   virtual CodeStub::Major MajorKey() { return StoreArrayLength; }
 };
 
 
+class HandlerStub: public ICStub {
+ public:
+  explicit HandlerStub(Code::Kind kind) : ICStub(kind) { }
+
+ protected:
+  virtual Code::ExtraICState GetExtraICState() {
+    return Code::HANDLER_FRAGMENT;
+  }
+};
+
+
+class LoadFieldStub: public HandlerStub {
+ public:
+  enum FieldMode { HEADER, INOBJECT, PROPERTIES };
+  LoadFieldStub(Register reg, bool inobject, int index)
+      : HandlerStub(Code::LOAD_IC), reg_(reg),

[Jakob Kummerow, 2013/03/01 22:21:04]

nit: let's give each initializer statement its own line.

[Toon Verwaest, 2013/03/04 10:54:08]

Done.

+        inobject_(inobject), index_(index) { }
+  virtual void Generate(MacroAssembler* masm);
+
+ protected:
+  virtual Code::StubType GetStubType() { return Code::FIELD; }
+
+ private:
+  class RegisterBits: public BitField<int, 1, 4> {};

[Jakob Kummerow, 2013/03/01 22:21:04]

Looks like something's wrong with those bit fields. The meaning of the template
arguments is "type, shift, size". ICStub::MinorKey() needs 4 bits. So you
probably want:
CodeKindBits -> int, 0, 4 (I'd make this explicit for clarity, and for getting
ASSERT coverage; use "CodeKindBits::encode(HandlerStub::MinorKey())" below.)
RegisterBits -> int, 4, 4 (is 4 bits enough on all platforms?)
InobjectBits -> bool, 8, 1
IndexBits -> int, 9, 16 (is there a reasonable upper limit for |index_|? If yes,
use that; otherwise 16 == kStubMinorKeyBits - 9).

[Toon Verwaest, 2013/03/04 10:54:08]

Doh, what did I do there.

2**11 is a reasonable upper limit for fast properties, given that that's the max
number of descriptors we support.

I used 6 bits for the registers as reasonable upper limit.

On 2013/03/01 22:21:04, Jakob wrote:

+  class InobjectBits: public BitField<bool, 6, 4> {};
+  class IndexBits: public BitField<int, 10, 11> {};
+  virtual CodeStub::Major MajorKey() { return LoadField; }
+  virtual int MinorKey() {
+    return HandlerStub::MinorKey()
+        | RegisterBits::encode(reg_.code())
+        | InobjectBits::encode(inobject_)
+        | IndexBits::encode(index_);
+  }
+
+  Register reg_;
+  bool inobject_;
+  int index_;
+};
+
+
 class BinaryOpStub: public PlatformCodeStub {
  public:
   BinaryOpStub(Token::Value op, OverwriteMode mode)
       : op_(op),
         mode_(mode),
         platform_specific_bit_(false),
         left_type_(BinaryOpIC::UNINITIALIZED),
         right_type_(BinaryOpIC::UNINITIALIZED),
         result_type_(BinaryOpIC::UNINITIALIZED) {
     Initialize();
@@ skipping 842 matching lines @@
 
   // The current function entry hook.
   static FunctionEntryHook entry_hook_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileEntryHookStub);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_