diff -r 0b27f3512f9e -r 37f87013dfd8 src/share/vm/memory/barrierSet.hpp
--- a/src/share/vm/memory/barrierSet.hpp	Wed Jun 04 13:51:09 2008 -0700
+++ b/src/share/vm/memory/barrierSet.hpp	Thu Jun 05 15:57:56 2008 -0700
@@ -32,6 +32,8 @@
     ModRef,
     CardTableModRef,
     CardTableExtension,
+    G1SATBCT,
+    G1SATBCTLogging,
     Other,
     Uninit
   };
@@ -42,14 +44,16 @@
 
 public:
 
+  BarrierSet() { _kind = Uninit; }
   // To get around prohibition on RTTI.
-  virtual BarrierSet::Name kind() { return _kind; }
+  BarrierSet::Name kind() { return _kind; }
   virtual bool is_a(BarrierSet::Name bsn) = 0;
 
   // These operations indicate what kind of barriers the BarrierSet has.
   virtual bool has_read_ref_barrier() = 0;
   virtual bool has_read_prim_barrier() = 0;
   virtual bool has_write_ref_barrier() = 0;
+  virtual bool has_write_ref_pre_barrier() = 0;
   virtual bool has_write_prim_barrier() = 0;
 
   // These functions indicate whether a particular access of the given
@@ -57,7 +61,8 @@
   virtual bool read_ref_needs_barrier(void* field) = 0;
   virtual bool read_prim_needs_barrier(HeapWord* field, size_t bytes) = 0;
   virtual bool write_ref_needs_barrier(void* field, oop new_val) = 0;
-  virtual bool write_prim_needs_barrier(HeapWord* field, size_t bytes, juint val1, juint val2) = 0;
+  virtual bool write_prim_needs_barrier(HeapWord* field, size_t bytes,
+                                        juint val1, juint val2) = 0;
 
   // The first four operations provide a direct implementation of the
   // barrier set.  An interpreter loop, for example, could call these
@@ -75,6 +80,13 @@
   // (For efficiency reasons, this operation is specialized for certain
   // barrier types.  Semantically, it should be thought of as a call to the
   // virtual "_work" function below, which must implement the barrier.)
+  // First the pre-write versions...
+  inline void write_ref_field_pre(void* field, oop new_val);
+protected:
+  virtual void write_ref_field_pre_work(void* field, oop new_val) {};
+public:
+
+  // ...then the post-write version.
   inline void write_ref_field(void* field, oop new_val);
 protected:
   virtual void write_ref_field_work(void* field, oop new_val) = 0;
@@ -92,6 +104,7 @@
   // the particular barrier.
   virtual bool has_read_ref_array_opt() = 0;
   virtual bool has_read_prim_array_opt() = 0;
+  virtual bool has_write_ref_array_pre_opt() { return true; }
   virtual bool has_write_ref_array_opt() = 0;
   virtual bool has_write_prim_array_opt() = 0;
 
@@ -104,7 +117,13 @@
   virtual void read_ref_array(MemRegion mr) = 0;
   virtual void read_prim_array(MemRegion mr) = 0;
 
+  virtual void write_ref_array_pre(MemRegion mr) {}
   inline void write_ref_array(MemRegion mr);
+
+  // Static versions, suitable for calling from generated code.
+  static void static_write_ref_array_pre(HeapWord* start, size_t count);
+  static void static_write_ref_array_post(HeapWord* start, size_t count);
+
 protected:
   virtual void write_ref_array_work(MemRegion mr) = 0;
 public:
@@ -120,33 +139,6 @@
   virtual void write_region_work(MemRegion mr) = 0;
 public:
 
-  // The remaining sets of operations are called by compilers or other code
-  // generators to insert barriers into generated code.  There may be
-  // several such code generators; the signatures of these
-  // barrier-generating functions may differ from generator to generator.
-  // There will be a set of four function signatures for each code
-  // generator, which accomplish the generation of barriers of the four
-  // kinds listed above.
-
-#ifdef TBD
-  // Generates code to invoke the barrier, if any, necessary when reading
-  // the ref field at "offset" in "obj".
-  virtual void gen_read_ref_field() = 0;
-
-  // Generates code to invoke the barrier, if any, necessary when reading
-  // the primitive field of "bytes" bytes at offset" in "obj".
-  virtual void gen_read_prim_field() = 0;
-
-  // Generates code to invoke the barrier, if any, necessary when writing
-  // "new_val" into the ref field at "offset" in "obj".
-  virtual void gen_write_ref_field() = 0;
-
-  // Generates code to invoke the barrier, if any, necessary when writing
-  // the "bytes"-byte value "new_val" into the primitive field at "offset"
-  // in "obj".
-  virtual void gen_write_prim_field() = 0;
-#endif
-
   // Some barrier sets create tables whose elements correspond to parts of
   // the heap; the CardTableModRefBS is an example.  Such barrier sets will
   // normally reserve space for such tables, and commit parts of the table