1 /*
   2  * Copyright (c) 2001, 2007, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SERIALGC
  26 
  27 class DirtyCardQueueSet;
  28 
  29 // This barrier is specialized to use a logging barrier to support
  30 // snapshot-at-the-beginning marking.
  31 
  32 class G1SATBCardTableModRefBS: public CardTableModRefBSForCTRS {
  33 private:
  34   // Add "pre_val" to a set of objects that may have been disconnected from the
  35   // pre-marking object graph.
  36   static void enqueue(oop pre_val);
  37 
  38 public:
  39   G1SATBCardTableModRefBS(MemRegion whole_heap,
  40                           int max_covered_regions);
  41 
  42   bool is_a(BarrierSet::Name bsn) {
  43     return bsn == BarrierSet::G1SATBCT || CardTableModRefBS::is_a(bsn);
  44   }
  45 
  46   virtual bool has_write_ref_pre_barrier() { return true; }
  47 
  48   // This notes that we don't need to access any BarrierSet data
  49   // structures, so this can be called from a static context.
  50   template <class T> static void write_ref_field_pre_static(T* field, oop newVal) {
  51     T heap_oop = oopDesc::load_heap_oop(field);
  52     if (!oopDesc::is_null(heap_oop)) {
  53       enqueue(oopDesc::decode_heap_oop(heap_oop));
  54     }
  55   }
  56 
  57   // When we know the current java thread:
  58   template <class T> static void write_ref_field_pre_static(T* field, oop newVal,
  59                                                             JavaThread* jt);
  60 
  61   // We export this to make it available in cases where the static
  62   // type of the barrier set is known.  Note that it is non-virtual.
  63   template <class T> inline void inline_write_ref_field_pre(T* field, oop newVal) {
  64     write_ref_field_pre_static(field, newVal);
  65   }
  66 
  67   // These are the more general virtual versions.
  68   virtual void write_ref_field_pre_work(oop* field, oop new_val) {
  69     inline_write_ref_field_pre(field, new_val);
  70   }
  71   virtual void write_ref_field_pre_work(narrowOop* field, oop new_val) {
  72     inline_write_ref_field_pre(field, new_val);
  73   }
  74   virtual void write_ref_field_pre_work(void* field, oop new_val) {
  75     guarantee(false, "Not needed");
  76   }
  77 
  78   template <class T> void write_ref_array_pre_work(T* dst, int count);
  79   virtual void write_ref_array_pre(oop* dst, int count) {
  80     write_ref_array_pre_work(dst, count);
  81   }
  82   virtual void write_ref_array_pre(narrowOop* dst, int count) {
  83     write_ref_array_pre_work(dst, count);
  84   }
  85 };
  86 
  87 // Adds card-table logging to the post-barrier.
  88 // Usual invariant: all dirty cards are logged in the DirtyCardQueueSet.
  89 class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS {
  90  private:
  91   DirtyCardQueueSet& _dcqs;
  92  public:
  93   G1SATBCardTableLoggingModRefBS(MemRegion whole_heap,
  94                                  int max_covered_regions);
  95 
  96   bool is_a(BarrierSet::Name bsn) {
  97     return bsn == BarrierSet::G1SATBCTLogging ||
  98       G1SATBCardTableModRefBS::is_a(bsn);
  99   }
 100 
 101   void write_ref_field_work(void* field, oop new_val);
 102 
 103   // Can be called from static contexts.
 104   static void write_ref_field_static(void* field, oop new_val);
 105 
 106   // NB: if you do a whole-heap invalidation, the "usual invariant" defined
 107   // above no longer applies.
 108   void invalidate(MemRegion mr, bool whole_heap = false);
 109 
 110   void write_region_work(MemRegion mr)    { invalidate(mr); }
 111   void write_ref_array_work(MemRegion mr) { invalidate(mr); }
 112 
 113 
 114 };
 115 
 116 
 117 #endif // SERIALGC