Add dependency to HLoadKeyed* instructions to prevent invalid hoisting

src/hydrogen-instructions.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 4009 matching lines @@
  public:
   virtual HValue* GetKey() = 0;
   virtual void SetKey(HValue* key) = 0;
   virtual void SetIndexOffset(uint32_t index_offset) = 0;
   virtual bool IsDehoisted() = 0;
   virtual void SetDehoisted(bool is_dehoisted) = 0;
   virtual ~ArrayInstructionInterface() { };
 };
 
 class HLoadKeyedFastElement
-    : public HTemplateInstruction<2>, public ArrayInstructionInterface {
+    : public HTemplateInstruction<3>, public ArrayInstructionInterface {
  public:
   HLoadKeyedFastElement(HValue* obj,
                         HValue* key,
+                        HValue* dependency,
                         ElementsKind elements_kind = FAST_ELEMENTS)
       : bit_field_(0) {
     ASSERT(IsFastSmiOrObjectElementsKind(elements_kind));
     bit_field_ = ElementsKindField::encode(elements_kind);
     if (IsFastSmiElementsKind(elements_kind) &&
         IsFastPackedElementsKind(elements_kind)) {
       set_type(HType::Smi());
     }
     SetOperandAt(0, obj);
     SetOperandAt(1, key);
+    SetOperandAt(2, dependency);
     set_representation(Representation::Tagged());
     SetGVNFlag(kDependsOnArrayElements);
     SetFlag(kUseGVN);
   }
 
   HValue* object() { return OperandAt(0); }
   HValue* key() { return OperandAt(1); }
+  HValue* dependency() { return OperandAt(2); }
   uint32_t index_offset() { return IndexOffsetField::decode(bit_field_); }
   void SetIndexOffset(uint32_t index_offset) {
     bit_field_ = IndexOffsetField::update(bit_field_, index_offset);
   }
   HValue* GetKey() { return key(); }
   void SetKey(HValue* key) { SetOperandAt(1, key); }
   bool IsDehoisted() { return IsDehoistedField::decode(bit_field_); }
   void SetDehoisted(bool is_dehoisted) {
     bit_field_ = IsDehoistedField::update(bit_field_, is_dehoisted);
   }
   ElementsKind elements_kind() const {
     return ElementsKindField::decode(bit_field_);
   }
 
   virtual Representation RequiredInputRepresentation(int index) {
     // The key is supposed to be Integer32.
-    return index == 0
-      ? Representation::Tagged()
-      : Representation::Integer32();
+    if (index == 0) return Representation::Tagged();
+    if (index == 1) return Representation::Integer32();
+    return Representation::None();
   }
 
   virtual void PrintDataTo(StringStream* stream);
 
   bool RequiresHoleCheck();
 
   DECLARE_CONCRETE_INSTRUCTION(LoadKeyedFastElement)
 
  protected:
   virtual bool DataEquals(HValue* other) {
     if (!other->IsLoadKeyedFastElement()) return false;
     HLoadKeyedFastElement* other_load = HLoadKeyedFastElement::cast(other);
     if (IsDehoisted() && index_offset() != other_load->index_offset())
       return false;
     return elements_kind() == other_load->elements_kind();
   }
 
  private:
   class ElementsKindField:  public BitField<ElementsKind, 0, 4> {};
   class IndexOffsetField:   public BitField<uint32_t, 4, 27> {};
   class IsDehoistedField:   public BitField<bool, 31, 1> {};
   uint32_t bit_field_;
 };
 
 
 enum HoleCheckMode { PERFORM_HOLE_CHECK, OMIT_HOLE_CHECK };
 
 
 class HLoadKeyedFastDoubleElement
-    : public HTemplateInstruction<2>, public ArrayInstructionInterface {
+    : public HTemplateInstruction<3>, public ArrayInstructionInterface {
  public:
   HLoadKeyedFastDoubleElement(
     HValue* elements,
     HValue* key,
+    HValue* dependency,
     HoleCheckMode hole_check_mode = PERFORM_HOLE_CHECK)
       : index_offset_(0),
         is_dehoisted_(false),
         hole_check_mode_(hole_check_mode) {
     SetOperandAt(0, elements);
     SetOperandAt(1, key);
+    SetOperandAt(2, dependency);
     set_representation(Representation::Double());
     SetGVNFlag(kDependsOnDoubleArrayElements);
     SetFlag(kUseGVN);
   }
 
   HValue* elements() { return OperandAt(0); }
   HValue* key() { return OperandAt(1); }
+  HValue* dependency() { return OperandAt(2); }
   uint32_t index_offset() { return index_offset_; }
   void SetIndexOffset(uint32_t index_offset) { index_offset_ = index_offset; }
   HValue* GetKey() { return key(); }
   void SetKey(HValue* key) { SetOperandAt(1, key); }
   bool IsDehoisted() { return is_dehoisted_; }
   void SetDehoisted(bool is_dehoisted) { is_dehoisted_ = is_dehoisted; }
 
   virtual Representation RequiredInputRepresentation(int index) {
     // The key is supposed to be Integer32.
-    return index == 0
-      ? Representation::Tagged()
-      : Representation::Integer32();
+    if (index == 0) return Representation::Tagged();
+    if (index == 1) return Representation::Integer32();
+    return Representation::None();
   }
 
   bool RequiresHoleCheck() {
     return hole_check_mode_ == PERFORM_HOLE_CHECK;
   }
 
   virtual void PrintDataTo(StringStream* stream);
 
   DECLARE_CONCRETE_INSTRUCTION(LoadKeyedFastDoubleElement)
 
  protected:
   virtual bool DataEquals(HValue* other) {
     if (!other->IsLoadKeyedFastDoubleElement()) return false;
     HLoadKeyedFastDoubleElement* other_load =
         HLoadKeyedFastDoubleElement::cast(other);
     return hole_check_mode_ == other_load->hole_check_mode_;
   }
 
  private:
   uint32_t index_offset_;
   bool is_dehoisted_;
   HoleCheckMode hole_check_mode_;
 };
 
 
 class HLoadKeyedSpecializedArrayElement
-    : public HTemplateInstruction<2>, public ArrayInstructionInterface {
+    : public HTemplateInstruction<3>, public ArrayInstructionInterface {
  public:
   HLoadKeyedSpecializedArrayElement(HValue* external_elements,
                                     HValue* key,
+                                    HValue* dependency,
                                     ElementsKind elements_kind)
       :  elements_kind_(elements_kind),
          index_offset_(0),
          is_dehoisted_(false) {
     SetOperandAt(0, external_elements);
     SetOperandAt(1, key);
+    SetOperandAt(2, dependency);
     if (elements_kind == EXTERNAL_FLOAT_ELEMENTS ||
         elements_kind == EXTERNAL_DOUBLE_ELEMENTS) {
       set_representation(Representation::Double());
     } else {
       set_representation(Representation::Integer32());
     }
     SetGVNFlag(kDependsOnSpecializedArrayElements);
     // Native code could change the specialized array.
     SetGVNFlag(kDependsOnCalls);
     SetFlag(kUseGVN);
   }
 
   virtual void PrintDataTo(StringStream* stream);
 
   virtual Representation RequiredInputRepresentation(int index) {
-    // The key is supposed to be Integer32, but the base pointer
-    // for the element load is a naked pointer.
-    return index == 0
-      ? Representation::External()
-      : Representation::Integer32();
+    // The key is supposed to be Integer32.
+    if (index == 0) return Representation::External();
+    if (index == 1) return Representation::Integer32();
+    return Representation::None();
   }
 
   HValue* external_pointer() { return OperandAt(0); }
   HValue* key() { return OperandAt(1); }
+  HValue* dependency() { return OperandAt(2); }
   ElementsKind elements_kind() const { return elements_kind_; }
   uint32_t index_offset() { return index_offset_; }
   void SetIndexOffset(uint32_t index_offset) { index_offset_ = index_offset; }
   HValue* GetKey() { return key(); }
   void SetKey(HValue* key) { SetOperandAt(1, key); }
   bool IsDehoisted() { return is_dehoisted_; }
   void SetDehoisted(bool is_dehoisted) { is_dehoisted_ = is_dehoisted; }
 
   virtual Range* InferRange(Zone* zone);
 
@@ skipping 951 matching lines @@
   DECLARE_CONCRETE_INSTRUCTION(LoadFieldByIndex);
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_