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 // The CollectedHeap type requires subtypes to implement a method
26 // "block_start". For some subtypes, notably generational
27 // systems using card-table-based write barriers, the efficiency of this
28 // operation may be important. Implementations of the "BlockOffsetArray"
29 // class may be useful in providing such efficient implementations.
30 //
31 // BlockOffsetTable (abstract)
32 // - BlockOffsetArray (abstract)
33 // - BlockOffsetArrayNonContigSpace
34 // - BlockOffsetArrayContigSpace
35 //
36
37 class ContiguousSpace;
38 class SerializeOopClosure;
39
40 //////////////////////////////////////////////////////////////////////////
41 // The BlockOffsetTable "interface"
42 //////////////////////////////////////////////////////////////////////////
43 class BlockOffsetTable VALUE_OBJ_CLASS_SPEC {
44 friend class VMStructs;
544 // [blk_start, blk_end) representing a block of memory in the heap.
545 // In this implementation, however, we are OK even if blk_start and/or
546 // blk_end are NULL because NULL is represented as 0, and thus
547 // never exceeds the "_next_offset_threshold".
548 void alloc_block(HeapWord* blk_start, HeapWord* blk_end) {
549 if (blk_end > _next_offset_threshold) {
550 alloc_block_work(blk_start, blk_end);
551 }
552 }
553 void alloc_block(HeapWord* blk, size_t size) {
554 alloc_block(blk, blk + size);
555 }
556
557 HeapWord* block_start_unsafe(const void* addr) const;
558
559 void serialize(SerializeOopClosure* soc);
560
561 // Debugging support
562 virtual size_t last_active_index() const;
563 };
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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 SHARE_VM_MEMORY_BLOCKOFFSETTABLE_HPP
26 #define SHARE_VM_MEMORY_BLOCKOFFSETTABLE_HPP
27
28 #include "memory/memRegion.hpp"
29 #include "runtime/virtualspace.hpp"
30 #include "utilities/globalDefinitions.hpp"
31
32 // The CollectedHeap type requires subtypes to implement a method
33 // "block_start". For some subtypes, notably generational
34 // systems using card-table-based write barriers, the efficiency of this
35 // operation may be important. Implementations of the "BlockOffsetArray"
36 // class may be useful in providing such efficient implementations.
37 //
38 // BlockOffsetTable (abstract)
39 // - BlockOffsetArray (abstract)
40 // - BlockOffsetArrayNonContigSpace
41 // - BlockOffsetArrayContigSpace
42 //
43
44 class ContiguousSpace;
45 class SerializeOopClosure;
46
47 //////////////////////////////////////////////////////////////////////////
48 // The BlockOffsetTable "interface"
49 //////////////////////////////////////////////////////////////////////////
50 class BlockOffsetTable VALUE_OBJ_CLASS_SPEC {
51 friend class VMStructs;
551 // [blk_start, blk_end) representing a block of memory in the heap.
552 // In this implementation, however, we are OK even if blk_start and/or
553 // blk_end are NULL because NULL is represented as 0, and thus
554 // never exceeds the "_next_offset_threshold".
555 void alloc_block(HeapWord* blk_start, HeapWord* blk_end) {
556 if (blk_end > _next_offset_threshold) {
557 alloc_block_work(blk_start, blk_end);
558 }
559 }
560 void alloc_block(HeapWord* blk, size_t size) {
561 alloc_block(blk, blk + size);
562 }
563
564 HeapWord* block_start_unsafe(const void* addr) const;
565
566 void serialize(SerializeOopClosure* soc);
567
568 // Debugging support
569 virtual size_t last_active_index() const;
570 };
571
572 #endif // SHARE_VM_MEMORY_BLOCKOFFSETTABLE_HPP
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