Thu, 07 Feb 2013 16:05:48 -0500
Merge
1 /*
2 * Copyright (c) 2000, 2012, 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 */
25 #ifndef SHARE_VM_MEMORY_MEMREGION_HPP
26 #define SHARE_VM_MEMORY_MEMREGION_HPP
28 #include "memory/allocation.hpp"
29 #include "utilities/debug.hpp"
30 #include "utilities/globalDefinitions.hpp"
32 // A very simple data structure representing a contigous region
33 // region of address space.
35 // Note that MemRegions are passed by value, not by reference.
36 // The intent is that they remain very small and contain no
37 // objects.
39 class MetaWord;
41 class MemRegion VALUE_OBJ_CLASS_SPEC {
42 friend class VMStructs;
43 private:
44 HeapWord* _start;
45 size_t _word_size;
47 public:
48 MemRegion() : _start(NULL), _word_size(0) {};
49 MemRegion(HeapWord* start, size_t word_size) :
50 _start(start), _word_size(word_size) {};
51 MemRegion(HeapWord* start, HeapWord* end) :
52 _start(start), _word_size(pointer_delta(end, start)) {
53 assert(end >= start, "incorrect constructor arguments");
54 }
55 MemRegion(MetaWord* start, MetaWord* end) :
56 _start((HeapWord*)start), _word_size(pointer_delta(end, start)) {
57 assert(end >= start, "incorrect constructor arguments");
58 }
60 MemRegion(const MemRegion& mr): _start(mr._start), _word_size(mr._word_size) {}
62 MemRegion intersection(const MemRegion mr2) const;
63 // regions must overlap or be adjacent
64 MemRegion _union(const MemRegion mr2) const;
65 // minus will fail a guarantee if mr2 is interior to this,
66 // since there's no way to return 2 disjoint regions.
67 MemRegion minus(const MemRegion mr2) const;
69 HeapWord* start() const { return _start; }
70 HeapWord* end() const { return _start + _word_size; }
71 HeapWord* last() const { return _start + _word_size - 1; }
73 void set_start(HeapWord* start) { _start = start; }
74 void set_end(HeapWord* end) { _word_size = pointer_delta(end, _start); }
75 void set_word_size(size_t word_size) {
76 _word_size = word_size;
77 }
79 bool contains(const MemRegion mr2) const {
80 return _start <= mr2._start && end() >= mr2.end();
81 }
82 bool contains(const void* addr) const {
83 return addr >= (void*)_start && addr < (void*)end();
84 }
85 bool equals(const MemRegion mr2) const {
86 // first disjunct since we do not have a canonical empty set
87 return ((is_empty() && mr2.is_empty()) ||
88 (start() == mr2.start() && end() == mr2.end()));
89 }
91 size_t byte_size() const { return _word_size * sizeof(HeapWord); }
92 size_t word_size() const { return _word_size; }
94 bool is_empty() const { return word_size() == 0; }
95 };
97 // For iteration over MemRegion's.
99 class MemRegionClosure : public StackObj {
100 public:
101 virtual void do_MemRegion(MemRegion mr) = 0;
102 };
104 // A ResourceObj version of MemRegionClosure
106 class MemRegionClosureRO: public MemRegionClosure {
107 public:
108 void* operator new(size_t size, ResourceObj::allocation_type type, MEMFLAGS flags) {
109 return ResourceObj::operator new(size, type, flags);
110 }
111 void* operator new(size_t size, Arena *arena) {
112 return ResourceObj::operator new(size, arena);
113 }
114 void* operator new(size_t size) {
115 return ResourceObj::operator new(size);
116 }
118 void operator delete(void* p) {} // nothing to do
119 };
121 #endif // SHARE_VM_MEMORY_MEMREGION_HPP