Re-land "Clusterfuzz identified overflow check needed in dehoisting."

src/hydrogen-instructions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HYDROGEN_INSTRUCTIONS_H_
 #define V8_HYDROGEN_INSTRUCTIONS_H_
 
 #include "src/v8.h"
 
 #include "src/allocation.h"
@@ skipping 6423 matching lines @@
     SetFlag(kUseGVN);
     SetDependsOnFlag(kCalls);
   }
 };
 
 class ArrayInstructionInterface {
  public:
   virtual HValue* GetKey() = 0;
   virtual void SetKey(HValue* key) = 0;
   virtual ElementsKind elements_kind() const = 0;
-  virtual void IncreaseBaseOffset(uint32_t base_offset) = 0;
-  virtual int MaxBaseOffsetBits() = 0;
+  // TryIncreaseBaseOffset returns false if overflow would result.
+  virtual bool TryIncreaseBaseOffset(uint32_t increase_by_value) = 0;
   virtual bool IsDehoisted() = 0;
   virtual void SetDehoisted(bool is_dehoisted) = 0;
   virtual ~ArrayInstructionInterface() { }
 
   static Representation KeyedAccessIndexRequirement(Representation r) {
     return r.IsInteger32() || SmiValuesAre32Bits()
         ? Representation::Integer32() : Representation::Smi();
   }
 };
 
@@ skipping 26 matching lines @@
     return is_external() || is_fixed_typed_array();
   }
   HValue* elements() { return OperandAt(0); }
   HValue* key() { return OperandAt(1); }
   HValue* dependency() {
     ASSERT(HasDependency());
     return OperandAt(2);
   }
   bool HasDependency() const { return OperandAt(0) != OperandAt(2); }
   uint32_t base_offset() { return BaseOffsetField::decode(bit_field_); }
-  void IncreaseBaseOffset(uint32_t base_offset) {
+  bool TryIncreaseBaseOffset(uint32_t increase_by_value) {
     // The base offset is usually simply the size of the array header, except
     // with dehoisting adds an addition offset due to a array index key
     // manipulation, in which case it becomes (array header size +
     // constant-offset-from-key * kPointerSize)
-    base_offset += BaseOffsetField::decode(bit_field_);
+    uint32_t base_offset = BaseOffsetField::decode(bit_field_);
+    if (AdditionOverflows(base_offset, increase_by_value) ||
+        !BaseOffsetField::is_valid(base_offset + increase_by_value)) {
+      return false;
+    }
+    base_offset += increase_by_value;
     bit_field_ = BaseOffsetField::update(bit_field_, base_offset);
-  }
-  virtual int MaxBaseOffsetBits() {
-    return kBitsForBaseOffset;
+    return true;
   }
   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);
   }
   virtual ElementsKind elements_kind() const V8_OVERRIDE {
     return ElementsKindField::decode(bit_field_);
   }
@@ skipping 444 matching lines @@
 
   HValue* elements() const { return OperandAt(0); }
   HValue* key() const { return OperandAt(1); }
   HValue* value() const { return OperandAt(2); }
   bool value_is_smi() const {
     return IsFastSmiElementsKind(elements_kind_);
   }
   StoreFieldOrKeyedMode store_mode() const { return store_mode_; }
   ElementsKind elements_kind() const { return elements_kind_; }
   uint32_t base_offset() { return base_offset_; }
-  void IncreaseBaseOffset(uint32_t base_offset) {
+  bool TryIncreaseBaseOffset(uint32_t increase_by_value) {
     // The base offset is usually simply the size of the array header, except
     // with dehoisting adds an addition offset due to a array index key
     // manipulation, in which case it becomes (array header size +
     // constant-offset-from-key * kPointerSize)
-    base_offset_ += base_offset;
-  }
-  virtual int MaxBaseOffsetBits() {
-    return 31 - ElementsKindToShiftSize(elements_kind_);
+    if (AdditionOverflows(base_offset_, increase_by_value)) return false;
+    base_offset_ += increase_by_value;
+    return true;
   }
   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; }
   bool IsUninitialized() { return is_uninitialized_; }
   void SetUninitialized(bool is_uninitialized) {
     is_uninitialized_ = is_uninitialized;
   }
 
@@ skipping 817 matching lines @@
 };
 
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_