| /* |
| * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_GC_SHARED_CMBITMAP_HPP |
| #define SHARE_VM_GC_SHARED_CMBITMAP_HPP |
| |
| #include "memory/memRegion.hpp" |
| #include "utilities/bitMap.hpp" |
| #include "utilities/globalDefinitions.hpp" |
| |
| // A generic CM bit map. This is essentially a wrapper around the BitMap |
| // class, with one bit per (1<<_shifter) HeapWords. |
| |
| class MarkBitMapRO { |
| protected: |
| MemRegion _covered; // The heap area covered by this bitmap. |
| HeapWord* _bmStartWord; // base address of range covered by map |
| size_t _bmWordSize; // map size (in #HeapWords covered) |
| const int _shifter; // map to char or bit |
| BitMapView _bm; // the bit map itself |
| |
| public: |
| // constructor |
| MarkBitMapRO(int shifter); |
| |
| // inquiries |
| HeapWord* startWord() const { return _bmStartWord; } |
| // the following is one past the last word in space |
| HeapWord* endWord() const { return _bmStartWord + _bmWordSize; } |
| |
| // read marks |
| |
| bool isMarked(HeapWord* addr) const { |
| assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize), |
| "outside underlying space?"); |
| return _bm.at(heapWordToOffset(addr)); |
| } |
| |
| // iteration |
| inline bool iterate(BitMapClosure* cl, MemRegion mr); |
| |
| // Return the address corresponding to the next marked bit at or after |
| // "addr", and before "limit", if "limit" is non-NULL. If there is no |
| // such bit, returns "limit" if that is non-NULL, or else "endWord()". |
| inline HeapWord* getNextMarkedWordAddress(const HeapWord* addr, |
| const HeapWord* limit = NULL) const; |
| |
| // conversion utilities |
| HeapWord* offsetToHeapWord(size_t offset) const { |
| return _bmStartWord + (offset << _shifter); |
| } |
| size_t heapWordToOffset(const HeapWord* addr) const { |
| return pointer_delta(addr, _bmStartWord) >> _shifter; |
| } |
| |
| // The argument addr should be the start address of a valid object |
| inline HeapWord* nextObject(HeapWord* addr); |
| |
| void print_on_error(outputStream* st, const char* prefix) const; |
| |
| // debugging |
| NOT_PRODUCT(bool covers(MemRegion rs) const;) |
| }; |
| |
| class MarkBitMap : public MarkBitMapRO { |
| private: |
| // Clear bitmap range |
| void do_clear(MemRegion mr, bool large); |
| |
| public: |
| static size_t compute_size(size_t heap_size); |
| // Returns the amount of bytes on the heap between two marks in the bitmap. |
| static size_t mark_distance(); |
| // Returns how many bytes (or bits) of the heap a single byte (or bit) of the |
| // mark bitmap corresponds to. This is the same as the mark distance above. static size_t heap_map_factor() { |
| static size_t heap_map_factor() { |
| return mark_distance(); |
| } |
| |
| MarkBitMap() : MarkBitMapRO(LogMinObjAlignment) {} |
| |
| // Initializes the underlying BitMap to cover the given area. |
| void initialize(MemRegion heap, MemRegion bitmap); |
| |
| // Write marks. |
| inline void mark(HeapWord* addr); |
| inline void clear(HeapWord* addr); |
| inline bool parMark(HeapWord* addr); |
| |
| // Clear range. For larger regions, use *_large. |
| void clear() { do_clear(_covered, true); } |
| void clear_range(MemRegion mr) { do_clear(mr, false); } |
| void clear_range_large(MemRegion mr) { do_clear(mr, true); } |
| }; |
| |
| #endif // SHARE_VM_GC_SHARED_CMBITMAP_HPP |