Introduce a hydrogen value for contexts, support context slot assignment.

src/hydrogen-instructions.h

 // Copyright 2011 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 79 matching lines @@
   V(CheckFunction)                             \
   V(CheckInstanceType)                         \
   V(CheckMap)                                  \
   V(CheckNonSmi)                               \
   V(CheckPrototypeMaps)                        \
   V(CheckSmi)                                  \
   V(Compare)                                   \
   V(CompareJSObjectEq)                         \
   V(CompareMap)                                \
   V(Constant)                                  \
+  V(Context)                                   \
   V(DeleteProperty)                            \
   V(Deoptimize)                                \
   V(Div)                                       \
   V(EnterInlined)                              \
   V(FixedArrayLength)                          \
   V(FunctionLiteral)                           \
   V(GlobalObject)                              \
   V(GlobalReceiver)                            \
   V(Goto)                                      \
   V(InstanceOf)                                \
@@ skipping 11 matching lines @@
   V(LoadFunctionPrototype)                     \
   V(LoadGlobal)                                \
   V(LoadKeyedFastElement)                      \
   V(LoadKeyedGeneric)                          \
   V(LoadNamedField)                            \
   V(LoadNamedGeneric)                          \
   V(Mod)                                       \
   V(Mul)                                       \
   V(ObjectLiteral)                             \
   V(OsrEntry)                                  \
+  V(OuterContext)                              \
   V(Parameter)                                 \
   V(Power)                                     \
   V(PushArgument)                              \
   V(RegExpLiteral)                             \
   V(Return)                                    \
   V(Sar)                                       \
   V(Shl)                                       \
   V(Shr)                                       \
   V(Simulate)                                  \
   V(StackCheck)                                \
+  V(StoreContextSlot)                          \
   V(StoreGlobal)                               \
   V(StoreKeyedFastElement)                     \
   V(StoreKeyedGeneric)                         \
   V(StoreNamedField)                           \
   V(StoreNamedGeneric)                         \
   V(StringCharCodeAt)                          \
   V(StringLength)                              \
   V(Sub)                                       \
   V(Test)                                      \
   V(Throw)                                     \
   V(Typeof)                                    \
   V(TypeofIs)                                  \
   V(UnaryMathOperation)                        \
   V(UnknownOSRValue)                           \
   V(ValueOf)
 
 #define GVN_FLAG_LIST(V)                       \
   V(Calls)                                     \
   V(InobjectFields)                            \
   V(BackingStoreFields)                        \
   V(ArrayElements)                             \
   V(GlobalVars)                                \
   V(Maps)                                      \
   V(ArrayLengths)                              \
+  V(ContextSlots)                              \
   V(OsrEntries)
 
 #define DECLARE_INSTRUCTION(type)                   \
   virtual bool Is##type() const { return true; }    \
   static H##type* cast(HValue* value) {             \
     ASSERT(value->Is##type());                      \
     return reinterpret_cast<H##type*>(value);       \
   }                                                 \
   Opcode opcode() const { return HValue::k##type; }
 
@@ skipping 864 matching lines @@
     argument_index_ = index;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(PushArgument, "push_argument")
 
  private:
   int argument_index_;
 };
 
 
-class HGlobalObject: public HInstruction {
+class HContext: public HInstruction {
  public:
-  HGlobalObject() {
+  HContext() {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
-    SetFlag(kDependsOnCalls);
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(Context, "context");
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
+};
+
+
+class HOuterContext: public HUnaryOperation {
+ public:
+  explicit HOuterContext(HValue* inner) : HUnaryOperation(inner) {
+    set_representation(Representation::Tagged());
+    SetFlag(kUseGVN);
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(OuterContext, "outer_context");
+
+ protected:
+  virtual bool DataEquals(HValue* other) const { return true; }
+};
+
+
+class HGlobalObject: public HUnaryOperation {
+ public:
+  explicit HGlobalObject(HValue* context) : HUnaryOperation(context) {
+    set_representation(Representation::Tagged());
+    SetFlag(kUseGVN);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(GlobalObject, "global_object")
 
  protected:
   virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
-class HGlobalReceiver: public HInstruction {
+class HGlobalReceiver: public HUnaryOperation {
  public:
-  HGlobalReceiver() {
+  explicit HGlobalReceiver(HValue* global_object)
+      : HUnaryOperation(global_object) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
-    SetFlag(kDependsOnCalls);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(GlobalReceiver, "global_receiver")
 
  protected:
   virtual bool DataEquals(HValue* other) const { return true; }
 };
 
 
 class HCall: public HInstruction {
@@ skipping 1513 matching lines @@
   virtual void PrintDataTo(StringStream* stream) const;
 
   DECLARE_CONCRETE_INSTRUCTION(StoreGlobal, "store_global")
 
  private:
   Handle<JSGlobalPropertyCell> cell_;
   bool check_hole_value_;
 };
 
 
-class HLoadContextSlot: public HInstruction {
+class HLoadContextSlot: public HUnaryOperation {
  public:
-  HLoadContextSlot(int context_chain_length , int slot_index)
-      : context_chain_length_(context_chain_length), slot_index_(slot_index) {
+  HLoadContextSlot(HValue* context , int slot_index)
+      : HUnaryOperation(context), slot_index_(slot_index) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
-    SetFlag(kDependsOnCalls);
+    SetFlag(kDependsOnContextSlots);
   }
 
-  int context_chain_length() const { return context_chain_length_; }
   int slot_index() const { return slot_index_; }
 
+  virtual Representation RequiredInputRepresentation(int index) const {

[fschneider, 2011/01/28 11:54:50]

I think we are not consistent with when to override this function. Until now we
left the default implementation (Representation::None) for cases where we don't
ever expect a conversion of the inputs. 

[Kevin Millikin (Chromium), 2011/02/03 08:37:23]

Do you think that's a good idea?  It seems like another unsafe default.

+    return Representation::Tagged();
+  }
+
   virtual void PrintDataTo(StringStream* stream) const;
 
-  virtual intptr_t Hashcode() const {
-    return context_chain_length() * 29 + slot_index();
-  }
-
   DECLARE_CONCRETE_INSTRUCTION(LoadContextSlot, "load_context_slot")
 
  protected:
   virtual bool DataEquals(HValue* other) const {
     HLoadContextSlot* b = HLoadContextSlot::cast(other);
-    return (context_chain_length() == b->context_chain_length())
-        && (slot_index() == b->slot_index());
+    return (slot_index() == b->slot_index());
   }
 
  private:
-  int context_chain_length_;
   int slot_index_;
 };
 
+
+class HStoreContextSlot: public HBinaryOperation {
+ public:
+  HStoreContextSlot(HValue* context, int slot_index, HValue* value)
+      : HBinaryOperation(context, value), slot_index_(slot_index) {
+    SetFlag(kChangesContextSlots);
+  }
+
+  HValue* context() const { return OperandAt(0); }
+  HValue* value() const { return OperandAt(1); }
+  int slot_index() const { return slot_index_; }
+
+  virtual Representation RequiredInputRepresentation(int index) const {
+    return Representation::Tagged();
+  }
+
+  virtual void PrintDataTo(StringStream* stream) const;
+
+  DECLARE_CONCRETE_INSTRUCTION(StoreContextSlot, "store_context_slot")
+
+ private:
+  int slot_index_;
+};
+
 
 class HLoadNamedField: public HUnaryOperation {
  public:
   HLoadNamedField(HValue* object, bool is_in_object, int offset)
       : HUnaryOperation(object),
         is_in_object_(is_in_object),
         offset_(offset) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     if (is_in_object) {
@@ skipping 166 matching lines @@
     if (is_in_object_) {
       SetFlag(kChangesInobjectFields);
     } else {
       SetFlag(kChangesBackingStoreFields);
     }
   }
 
   DECLARE_CONCRETE_INSTRUCTION(StoreNamedField, "store_named_field")
 
   virtual Representation RequiredInputRepresentation(int index) const {
-    return  Representation::Tagged();
+    return Representation::Tagged();
   }
   virtual void PrintDataTo(StringStream* stream) const;
 
   bool is_in_object() const { return is_in_object_; }
   int offset() const { return offset_; }
   Handle<Map> transition() const { return transition_; }
   void set_transition(Handle<Map> map) { transition_ = map; }
 
  private:
   bool is_in_object_;
@@ skipping 272 matching lines @@
   HValue* object() const { return left(); }
   HValue* key() const { return right(); }
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_