1 /*
   2  * Copyright (c) 2001, 2014, 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.
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  23  */
  24 
  25 #ifndef SHARE_VM_MEMORY_GENOOPCLOSURES_INLINE_HPP
  26 #define SHARE_VM_MEMORY_GENOOPCLOSURES_INLINE_HPP
  27 
  28 #include "memory/cardTableRS.hpp"
  29 #include "memory/defNewGeneration.hpp"
  30 #include "memory/genCollectedHeap.hpp"
  31 #include "memory/genOopClosures.hpp"
  32 #include "memory/genRemSet.hpp"
  33 #include "memory/generation.hpp"
  34 #include "memory/sharedHeap.hpp"
  35 #include "memory/space.hpp"
  36 
  37 inline OopsInGenClosure::OopsInGenClosure(Generation* gen) :
  38   ExtendedOopClosure(gen->ref_processor()), _orig_gen(gen), _rs(NULL) {
  39   set_generation(gen);
  40 }
  41 
  42 inline void OopsInGenClosure::set_generation(Generation* gen) {
  43   _gen = gen;
  44   _gen_boundary = _gen->reserved().start();
  45   // Barrier set for the heap, must be set after heap is initialized
  46   if (_rs == NULL) {
  47     GenRemSet* rs = GenCollectedHeap::heap()->rem_set();
  48     _rs = (CardTableRS*)rs;
  49   }
  50 }
  51 
  52 template <class T> inline void OopsInGenClosure::do_barrier(T* p) {
  53   assert(generation()->is_in_reserved(p), "expected ref in generation");
  54   T heap_oop = oopDesc::load_heap_oop(p);
  55   assert(!oopDesc::is_null(heap_oop), "expected non-null oop");
  56   oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
  57   // If p points to a younger generation, mark the card.
  58   if ((HeapWord*)obj < _gen_boundary) {
  59     _rs->inline_write_ref_field_gc(p, obj);
  60   }
  61 }
  62 
  63 template <class T> inline void OopsInGenClosure::par_do_barrier(T* p) {
  64   assert(generation()->is_in_reserved(p), "expected ref in generation");
  65   T heap_oop = oopDesc::load_heap_oop(p);
  66   assert(!oopDesc::is_null(heap_oop), "expected non-null oop");
  67   oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
  68   // If p points to a younger generation, mark the card.
  69   if ((HeapWord*)obj < gen_boundary()) {
  70     rs()->write_ref_field_gc_par(p, obj);
  71   }
  72 }
  73 
  74 inline void OopsInKlassOrGenClosure::do_klass_barrier() {
  75   assert(_scanned_klass != NULL, "Must be");
  76   _scanned_klass->record_modified_oops();
  77 }
  78 
  79 // NOTE! Any changes made here should also be made
  80 // in FastScanClosure::do_oop_work()
  81 template <class T> inline void ScanClosure::do_oop_work(T* p) {
  82   T heap_oop = oopDesc::load_heap_oop(p);
  83   // Should we copy the obj?
  84   if (!oopDesc::is_null(heap_oop)) {
  85     oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
  86     if ((HeapWord*)obj < _boundary) {
  87       assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?");
  88       oop new_obj = obj->is_forwarded() ? obj->forwardee()
  89                                         : _g->copy_to_survivor_space(obj);
  90       oopDesc::encode_store_heap_oop_not_null(p, new_obj);
  91     }
  92 
  93     if (is_scanning_a_klass()) {
  94       do_klass_barrier();
  95     } else if (_gc_barrier) {
  96       // Now call parent closure
  97       do_barrier(p);
  98     }
  99   }
 100 }
 101 
 102 inline void ScanClosure::do_oop_nv(oop* p)       { ScanClosure::do_oop_work(p); }
 103 inline void ScanClosure::do_oop_nv(narrowOop* p) { ScanClosure::do_oop_work(p); }
 104 
 105 // NOTE! Any changes made here should also be made
 106 // in ScanClosure::do_oop_work()
 107 template <class T> inline void FastScanClosure::do_oop_work(T* p) {
 108   T heap_oop = oopDesc::load_heap_oop(p);
 109   // Should we copy the obj?
 110   if (!oopDesc::is_null(heap_oop)) {
 111     oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
 112     if ((HeapWord*)obj < _boundary) {
 113       assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?");
 114       oop new_obj = obj->is_forwarded() ? obj->forwardee()
 115                                         : _g->copy_to_survivor_space(obj);
 116       oopDesc::encode_store_heap_oop_not_null(p, new_obj);
 117       if (is_scanning_a_klass()) {
 118         do_klass_barrier();
 119       } else if (_gc_barrier) {
 120         // Now call parent closure
 121         do_barrier(p);
 122       }
 123     }
 124   }
 125 }
 126 
 127 inline void FastScanClosure::do_oop_nv(oop* p)       { FastScanClosure::do_oop_work(p); }
 128 inline void FastScanClosure::do_oop_nv(narrowOop* p) { FastScanClosure::do_oop_work(p); }
 129 
 130 // Note similarity to ScanClosure; the difference is that
 131 // the barrier set is taken care of outside this closure.
 132 template <class T> inline void ScanWeakRefClosure::do_oop_work(T* p) {
 133   assert(!oopDesc::is_null(*p), "null weak reference?");
 134   oop obj = oopDesc::load_decode_heap_oop_not_null(p);
 135   // weak references are sometimes scanned twice; must check
 136   // that to-space doesn't already contain this object
 137   if ((HeapWord*)obj < _boundary && !_g->to()->is_in_reserved(obj)) {
 138     oop new_obj = obj->is_forwarded() ? obj->forwardee()
 139                                       : _g->copy_to_survivor_space(obj);
 140     oopDesc::encode_store_heap_oop_not_null(p, new_obj);
 141   }
 142 }
 143 
 144 inline void ScanWeakRefClosure::do_oop_nv(oop* p)       { ScanWeakRefClosure::do_oop_work(p); }
 145 inline void ScanWeakRefClosure::do_oop_nv(narrowOop* p) { ScanWeakRefClosure::do_oop_work(p); }
 146 
 147 #endif // SHARE_VM_MEMORY_GENOOPCLOSURES_INLINE_HPP