Thu, 11 Dec 2008 12:05:08 -0800
6578152: fill_region_with_object has usability and safety issues
Reviewed-by: apetrusenko, ysr
duke@435 | 1 | /* |
duke@435 | 2 | * Copyright 2000-2004 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | // A very simple data structure representing a contigous region |
duke@435 | 26 | // region of address space. |
duke@435 | 27 | |
duke@435 | 28 | // Note that MemRegions are passed by value, not by reference. |
duke@435 | 29 | // The intent is that they remain very small and contain no |
duke@435 | 30 | // objects. |
duke@435 | 31 | |
duke@435 | 32 | class MemRegion VALUE_OBJ_CLASS_SPEC { |
duke@435 | 33 | friend class VMStructs; |
duke@435 | 34 | private: |
duke@435 | 35 | HeapWord* _start; |
duke@435 | 36 | size_t _word_size; |
duke@435 | 37 | |
duke@435 | 38 | public: |
duke@435 | 39 | MemRegion() : _start(NULL), _word_size(0) {}; |
duke@435 | 40 | MemRegion(HeapWord* start, size_t word_size) : |
duke@435 | 41 | _start(start), _word_size(word_size) {}; |
duke@435 | 42 | MemRegion(HeapWord* start, HeapWord* end) : |
duke@435 | 43 | _start(start), _word_size(pointer_delta(end, start)) { |
duke@435 | 44 | assert(end >= start, "incorrect constructor arguments"); |
duke@435 | 45 | } |
duke@435 | 46 | |
duke@435 | 47 | MemRegion(const MemRegion& mr): _start(mr._start), _word_size(mr._word_size) {} |
duke@435 | 48 | |
duke@435 | 49 | MemRegion intersection(const MemRegion mr2) const; |
duke@435 | 50 | // regions must overlap or be adjacent |
duke@435 | 51 | MemRegion _union(const MemRegion mr2) const; |
duke@435 | 52 | // minus will fail a guarantee if mr2 is interior to this, |
duke@435 | 53 | // since there's no way to return 2 disjoint regions. |
duke@435 | 54 | MemRegion minus(const MemRegion mr2) const; |
duke@435 | 55 | |
duke@435 | 56 | HeapWord* start() const { return _start; } |
duke@435 | 57 | HeapWord* end() const { return _start + _word_size; } |
duke@435 | 58 | HeapWord* last() const { return _start + _word_size - 1; } |
duke@435 | 59 | |
duke@435 | 60 | void set_start(HeapWord* start) { _start = start; } |
duke@435 | 61 | void set_end(HeapWord* end) { _word_size = pointer_delta(end, _start); } |
duke@435 | 62 | void set_word_size(size_t word_size) { |
duke@435 | 63 | _word_size = word_size; |
duke@435 | 64 | } |
duke@435 | 65 | |
duke@435 | 66 | bool contains(const MemRegion mr2) const { |
duke@435 | 67 | return _start <= mr2._start && end() >= mr2.end(); |
duke@435 | 68 | } |
duke@435 | 69 | bool contains(const void* addr) const { |
duke@435 | 70 | return addr >= (void*)_start && addr < (void*)end(); |
duke@435 | 71 | } |
duke@435 | 72 | bool equals(const MemRegion mr2) const { |
duke@435 | 73 | // first disjunct since we do not have a canonical empty set |
duke@435 | 74 | return ((is_empty() && mr2.is_empty()) || |
duke@435 | 75 | (start() == mr2.start() && end() == mr2.end())); |
duke@435 | 76 | } |
duke@435 | 77 | |
duke@435 | 78 | size_t byte_size() const { return _word_size * sizeof(HeapWord); } |
duke@435 | 79 | size_t word_size() const { return _word_size; } |
duke@435 | 80 | |
duke@435 | 81 | bool is_empty() const { return word_size() == 0; } |
duke@435 | 82 | }; |
duke@435 | 83 | |
duke@435 | 84 | // For iteration over MemRegion's. |
duke@435 | 85 | |
duke@435 | 86 | class MemRegionClosure : public StackObj { |
duke@435 | 87 | public: |
duke@435 | 88 | virtual void do_MemRegion(MemRegion mr) = 0; |
duke@435 | 89 | }; |
duke@435 | 90 | |
duke@435 | 91 | // A ResourceObj version of MemRegionClosure |
duke@435 | 92 | |
duke@435 | 93 | class MemRegionClosureRO: public MemRegionClosure { |
duke@435 | 94 | public: |
duke@435 | 95 | void* operator new(size_t size, ResourceObj::allocation_type type) { |
duke@435 | 96 | return ResourceObj::operator new(size, type); |
duke@435 | 97 | } |
duke@435 | 98 | void* operator new(size_t size, Arena *arena) { |
duke@435 | 99 | return ResourceObj::operator new(size, arena); |
duke@435 | 100 | } |
duke@435 | 101 | void* operator new(size_t size) { |
duke@435 | 102 | return ResourceObj::operator new(size); |
duke@435 | 103 | } |
duke@435 | 104 | |
duke@435 | 105 | void operator delete(void* p) {} // nothing to do |
duke@435 | 106 | }; |