40     CardTableExtension,
  41     G1SATBCT,
  42     G1SATBCTLogging,
  43     Other,
  44     Uninit
  45   };
  46 
  47   enum Flags {
  48     None                = 0,
  49     TargetUninitialized = 1
  50   };
  51 protected:
  52   // Some barrier sets create tables whose elements correspond to parts of
  53   // the heap; the CardTableModRefBS is an example.  Such barrier sets will
  54   // normally reserve space for such tables, and commit parts of the table
  55   // "covering" parts of the heap that are committed. At most one covered
  56   // region per generation is needed.
  57   static const int _max_covered_regions = 2;
  58   Name _kind;
  59 



  60 public:
  61 
  62   BarrierSet() { _kind = Uninit; }
  63   // To get around prohibition on RTTI.
  64   BarrierSet::Name kind() { return _kind; }
  65   virtual bool is_a(BarrierSet::Name bsn) = 0;
  66 
  67   // These operations indicate what kind of barriers the BarrierSet has.
  68   virtual bool has_read_ref_barrier() = 0;
  69   virtual bool has_read_prim_barrier() = 0;
  70   virtual bool has_write_ref_barrier() = 0;
  71   virtual bool has_write_ref_pre_barrier() = 0;
  72   virtual bool has_write_prim_barrier() = 0;
  73 
  74   // These functions indicate whether a particular access of the given
  75   // kinds requires a barrier.
  76   virtual bool read_ref_needs_barrier(void* field) = 0;
  77   virtual bool read_prim_needs_barrier(HeapWord* field, size_t bytes) = 0;
  78   virtual bool write_prim_needs_barrier(HeapWord* field, size_t bytes,
  79                                         juint val1, juint val2) = 0;
  80 
  81   // The first four operations provide a direct implementation of the
  82   // barrier set.  An interpreter loop, for example, could call these

  40     CardTableExtension,
  41     G1SATBCT,
  42     G1SATBCTLogging,
  43     Other,
  44     Uninit
  45   };
  46 
  47   enum Flags {
  48     None                = 0,
  49     TargetUninitialized = 1
  50   };
  51 protected:
  52   // Some barrier sets create tables whose elements correspond to parts of
  53   // the heap; the CardTableModRefBS is an example.  Such barrier sets will
  54   // normally reserve space for such tables, and commit parts of the table
  55   // "covering" parts of the heap that are committed. At most one covered
  56   // region per generation is needed.
  57   static const int _max_covered_regions = 2;
  58   Name _kind;
  59 
  60   BarrierSet(Name kind) { _kind = kind; }
  61   ~BarrierSet() { }
  62 
  63 public:
  64 

  65   // To get around prohibition on RTTI.
  66   BarrierSet::Name kind() { return _kind; }
  67   virtual bool is_a(BarrierSet::Name bsn) = 0;
  68 
  69   // These operations indicate what kind of barriers the BarrierSet has.
  70   virtual bool has_read_ref_barrier() = 0;
  71   virtual bool has_read_prim_barrier() = 0;
  72   virtual bool has_write_ref_barrier() = 0;
  73   virtual bool has_write_ref_pre_barrier() = 0;
  74   virtual bool has_write_prim_barrier() = 0;
  75 
  76   // These functions indicate whether a particular access of the given
  77   // kinds requires a barrier.
  78   virtual bool read_ref_needs_barrier(void* field) = 0;
  79   virtual bool read_prim_needs_barrier(HeapWord* field, size_t bytes) = 0;
  80   virtual bool write_prim_needs_barrier(HeapWord* field, size_t bytes,
  81                                         juint val1, juint val2) = 0;
  82 
  83   // The first four operations provide a direct implementation of the
  84   // barrier set.  An interpreter loop, for example, could call these