Done rely on C++ object padding across platforms

src/deoptimizer.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 308 matching lines @@
   friend class DeoptimizingCodeListNode;
 };
 
 
 class FrameDescription {
  public:
   FrameDescription(uint32_t frame_size,
                    JSFunction* function);
 
   void* operator new(size_t size, uint32_t frame_size) {
-    return malloc(size + frame_size);
+    // Subtracts kPointerSize, as the member frame_content_ already supplies
+    // the first element of the area to store the frame.
+    return malloc(size + frame_size - kPointerSize);
   }
 
   void operator delete(void* description) {
     free(description);
   }
 
   intptr_t GetFrameSize() const { return frame_size_; }
 
   JSFunction* GetFunction() const { return function_; }
 
@@ skipping 63 matching lines @@
 
   static int state_offset() {
     return OFFSET_OF(FrameDescription, state_);
   }
 
   static int continuation_offset() {
     return OFFSET_OF(FrameDescription, continuation_);
   }
 
   static int frame_content_offset() {
-    return sizeof(FrameDescription);
+    return OFFSET_OF(FrameDescription, frame_content_);
   }
 
  private:
   static const uint32_t kZapUint32 = 0xbeeddead;
 
   uintptr_t frame_size_;  // Number of bytes.
   JSFunction* function_;
   intptr_t registers_[Register::kNumRegisters];
   double double_registers_[DoubleRegister::kNumAllocatableRegisters];
   intptr_t top_;
   intptr_t pc_;
   intptr_t fp_;
   Smi* state_;
 
   // Continuation is the PC where the execution continues after
   // deoptimizing.
   intptr_t continuation_;
 
+  // This must be at the end of the object as the object is allocated larger
+  // than it's definition indicate to extend this array.
+  intptr_t frame_content_[1];
+
   intptr_t* GetFrameSlotPointer(unsigned offset) {
     ASSERT(offset < frame_size_);
     return reinterpret_cast<intptr_t*>(
         reinterpret_cast<Address>(this) + frame_content_offset() + offset);
   }
 };
 
 
 class TranslationBuffer BASE_EMBEDDED {
  public:
@@ skipping 100 matching lines @@
   Handle<Code> code_;
 
   // Next pointer for linked list.
   DeoptimizingCodeListNode* next_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_DEOPTIMIZER_H_