| /* |
| * Copyright (c) 2000, 2013, 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_MEMORY_MEMREGION_HPP |
| #define SHARE_VM_MEMORY_MEMREGION_HPP |
| |
| #include "memory/allocation.hpp" |
| #include "utilities/debug.hpp" |
| #include "utilities/globalDefinitions.hpp" |
| |
| // A very simple data structure representing a contigous region |
| // region of address space. |
| |
| // Note that MemRegions are passed by value, not by reference. |
| // The intent is that they remain very small and contain no |
| // objects. _ValueObj should never be allocated in heap but we do |
| // create MemRegions (in CardTableModRefBS) in heap so operator |
| // new and operator new [] added for this special case. |
| |
| class MetaWord; |
| |
| class MemRegion VALUE_OBJ_CLASS_SPEC { |
| friend class VMStructs; |
| private: |
| HeapWord* _start; |
| size_t _word_size; |
| |
| public: |
| MemRegion() : _start(NULL), _word_size(0) {}; |
| MemRegion(HeapWord* start, size_t word_size) : |
| _start(start), _word_size(word_size) {}; |
| MemRegion(HeapWord* start, HeapWord* end) : |
| _start(start), _word_size(pointer_delta(end, start)) { |
| assert(end >= start, "incorrect constructor arguments"); |
| } |
| MemRegion(MetaWord* start, MetaWord* end) : |
| _start((HeapWord*)start), _word_size(pointer_delta(end, start)) { |
| assert(end >= start, "incorrect constructor arguments"); |
| } |
| |
| MemRegion(const MemRegion& mr): _start(mr._start), _word_size(mr._word_size) {} |
| |
| MemRegion intersection(const MemRegion mr2) const; |
| // regions must overlap or be adjacent |
| MemRegion _union(const MemRegion mr2) const; |
| // minus will fail a guarantee if mr2 is interior to this, |
| // since there's no way to return 2 disjoint regions. |
| MemRegion minus(const MemRegion mr2) const; |
| |
| HeapWord* start() const { return _start; } |
| HeapWord* end() const { return _start + _word_size; } |
| HeapWord* last() const { return _start + _word_size - 1; } |
| |
| void set_start(HeapWord* start) { _start = start; } |
| void set_end(HeapWord* end) { _word_size = pointer_delta(end, _start); } |
| void set_word_size(size_t word_size) { |
| _word_size = word_size; |
| } |
| |
| bool contains(const MemRegion mr2) const { |
| return _start <= mr2._start && end() >= mr2.end(); |
| } |
| bool contains(const void* addr) const { |
| return addr >= (void*)_start && addr < (void*)end(); |
| } |
| bool equals(const MemRegion mr2) const { |
| // first disjunct since we do not have a canonical empty set |
| return ((is_empty() && mr2.is_empty()) || |
| (start() == mr2.start() && end() == mr2.end())); |
| } |
| |
| size_t byte_size() const { return _word_size * sizeof(HeapWord); } |
| size_t word_size() const { return _word_size; } |
| |
| bool is_empty() const { return word_size() == 0; } |
| void* operator new(size_t size) throw(); |
| void* operator new [](size_t size) throw(); |
| void operator delete(void* p); |
| void operator delete [](void* p); |
| }; |
| |
| // For iteration over MemRegion's. |
| |
| class MemRegionClosure : public StackObj { |
| public: |
| virtual void do_MemRegion(MemRegion mr) = 0; |
| }; |
| |
| // A ResourceObj version of MemRegionClosure |
| |
| class MemRegionClosureRO: public MemRegionClosure { |
| public: |
| void* operator new(size_t size, ResourceObj::allocation_type type, MEMFLAGS flags) throw() { |
| return ResourceObj::operator new(size, type, flags); |
| } |
| void* operator new(size_t size, Arena *arena) throw() { |
| return ResourceObj::operator new(size, arena); |
| } |
| void* operator new(size_t size) throw() { |
| return ResourceObj::operator new(size); |
| } |
| |
| void operator delete(void* p) {} // nothing to do |
| }; |
| |
| #endif // SHARE_VM_MEMORY_MEMREGION_HPP |