src/hotspot/share/gc/g1/g1BlockOffsetTable.hpp

rev 56201 : 8225716: G1 GC: Undefined behaviour in G1BlockOffsetTablePart::block_at_or_preceding
Reviewed-by: kbarrett, tschatzl

*** 50,60 ****
    // The reserved region covered by the table.
    MemRegion _reserved;
  
    // Array for keeping offsets for retrieving object start fast given an
    // address.
!   u_char* _offset_array;          // byte array keeping backwards offsets
  
    void check_offset(size_t offset, const char* msg) const {
      assert(offset <= BOTConstants::N_words,
             "%s - offset: " SIZE_FORMAT ", N_words: %u",
             msg, offset, BOTConstants::N_words);
--- 50,60 ----
    // The reserved region covered by the table.
    MemRegion _reserved;
  
    // Array for keeping offsets for retrieving object start fast given an
    // address.
!   volatile u_char* _offset_array;  // byte array keeping backwards offsets
  
    void check_offset(size_t offset, const char* msg) const {
      assert(offset <= BOTConstants::N_words,
             "%s - offset: " SIZE_FORMAT ", N_words: %u",
             msg, offset, BOTConstants::N_words);
*** 62,75 ****
  
    // Bounds checking accessors:
    // For performance these have to devolve to array accesses in product builds.
    inline u_char offset_array(size_t index) const;
  
!   void set_offset_array_raw(size_t index, u_char offset) {
!     _offset_array[index] = offset;
!   }
! 
    inline void set_offset_array(size_t index, u_char offset);
  
    inline void set_offset_array(size_t index, HeapWord* high, HeapWord* low);
  
    inline void set_offset_array(size_t left, size_t right, u_char offset);
--- 62,72 ----
  
    // Bounds checking accessors:
    // For performance these have to devolve to array accesses in product builds.
    inline u_char offset_array(size_t index) const;
  
!   inline void set_offset_array_raw(size_t index, u_char offset);
    inline void set_offset_array(size_t index, u_char offset);
  
    inline void set_offset_array(size_t index, HeapWord* high, HeapWord* low);
  
    inline void set_offset_array(size_t left, size_t right, u_char offset);