Simplify and fix code aging.

src/objects.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 4307 matching lines @@
   // [gc_metadata]: Field used to hold GC related metadata. The contents of this
   // field does not have to be traced during garbage collection since
   // it is only used by the garbage collector itself.
   DECL_ACCESSORS(gc_metadata, Object)
 
   // [ic_age]: Inline caching age: the value of the Heap::global_ic_age
   // at the moment when this object was created.
   inline void set_ic_age(int count);
   inline int ic_age();
 
+  // [prologue_offset]: Offset of the function prologue, used for aging
+  // FUNCTIONs and OPTIMIZED_FUNCTIONs.
+  inline int prologue_offset();
+  inline void set_prologue_offset(int offset);
+
   // Unchecked accessors to be used during GC.
   inline ByteArray* unchecked_relocation_info();
   inline FixedArray* unchecked_deoptimization_data();
 
   inline int relocation_size();
 
   // [flags]: Various code flags.
   inline Flags flags();
   inline void set_flags(Flags flags);
 
@@ skipping 248 matching lines @@
       kHandlerTableOffset + kPointerSize;
   static const int kTypeFeedbackInfoOffset =
       kDeoptimizationDataOffset + kPointerSize;
   static const int kGCMetadataOffset = kTypeFeedbackInfoOffset + kPointerSize;
   static const int kICAgeOffset =
       kGCMetadataOffset + kPointerSize;
   static const int kFlagsOffset = kICAgeOffset + kIntSize;
   static const int kKindSpecificFlags1Offset = kFlagsOffset + kIntSize;
   static const int kKindSpecificFlags2Offset =
       kKindSpecificFlags1Offset + kIntSize;
+  // Note: We might be able to squeeze this into the flags above.
+  static const int kPrologueOffset = kKindSpecificFlags2Offset + kIntSize;
 
-  static const int kHeaderPaddingStart = kKindSpecificFlags2Offset + kIntSize;
+  static const int kHeaderPaddingStart = kPrologueOffset + kIntSize;
 
   // Add padding to align the instruction start following right after
   // the Code object header.
   static const int kHeaderSize =
       (kHeaderPaddingStart + kCodeAlignmentMask) & ~kCodeAlignmentMask;
 
   // Byte offsets within kKindSpecificFlags1Offset.
   static const int kOptimizableOffset = kKindSpecificFlags1Offset;
   static const int kCheckTypeOffset = kKindSpecificFlags1Offset;
 
@@ skipping 73 matching lines @@
 
   // Code aging
   byte* FindCodeAgeSequence();
   static void  GetCodeAgeAndParity(Code* code, Age* age,
                                    MarkingParity* parity);
   static void GetCodeAgeAndParity(byte* sequence, Age* age,
                                   MarkingParity* parity);
   static Code* GetCodeAgeStub(Age age, MarkingParity parity);
 
   // Code aging -- platform-specific
-  byte* FindPlatformCodeAgeSequence();
   static void PatchPlatformCodeAge(byte* sequence, Age age,
                                    MarkingParity parity);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(Code);
 };
 
 
 // All heap objects have a Map that describes their structure.
 //  A Map contains information about:
 //  - Size information about the object
@@ skipping 4301 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_