1 /*
2 * Copyright (c) 2001, 2019, 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.
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23 */
24
25 #ifndef SHARE_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
26 #define SHARE_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
27
28 #include "gc/g1/g1BlockOffsetTable.hpp"
29 #include "gc/g1/heapRegion.hpp"
30 #include "gc/shared/memset_with_concurrent_readers.hpp"
31 #include "runtime/atomic.hpp"
32
33 inline HeapWord* G1BlockOffsetTablePart::block_start(const void* addr) {
34 if (addr >= _hr->bottom() && addr < _hr->end()) {
35 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
36 return forward_to_block_containing_addr(q, addr);
37 } else {
38 return NULL;
39 }
40 }
41
42 inline HeapWord* G1BlockOffsetTablePart::block_start_const(const void* addr) const {
43 if (addr >= _hr->bottom() && addr < _hr->end()) {
44 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
45 HeapWord* n = q + block_size(q);
46 return forward_to_block_containing_addr_const(q, n, addr);
47 } else {
48 return NULL;
49 }
50 }
51
52 u_char G1BlockOffsetTable::offset_array(size_t index) const {
53 check_index(index, "index out of range");
54 return Atomic::load(&_offset_array[index]);
55 }
56
57 void G1BlockOffsetTable::set_offset_array_raw(size_t index, u_char offset) {
58 Atomic::store(&_offset_array[index], offset);
59 }
60
61 void G1BlockOffsetTable::set_offset_array(size_t index, u_char offset) {
62 check_index(index, "index out of range");
63 set_offset_array_raw(index, offset);
64 }
65
66 void G1BlockOffsetTable::set_offset_array(size_t index, HeapWord* high, HeapWord* low) {
67 check_index(index, "index out of range");
68 assert(high >= low, "addresses out of order");
69 size_t offset = pointer_delta(high, low);
70 check_offset(offset, "offset too large");
71 set_offset_array(index, (u_char)offset);
72 }
73
74 void G1BlockOffsetTable::set_offset_array(size_t left, size_t right, u_char offset) {
75 check_index(right, "right index out of range");
76 assert(left <= right, "indexes out of order");
77 size_t num_cards = right - left + 1;
78 memset_with_concurrent_readers
79 (const_cast<u_char*> (&_offset_array[left]), offset, num_cards);
80 }
81
82 // Variant of index_for that does not check the index for validity.
83 inline size_t G1BlockOffsetTable::index_for_raw(const void* p) const {
84 return pointer_delta((char*)p, _reserved.start(), sizeof(char)) >> BOTConstants::LogN;
85 }
86
87 inline size_t G1BlockOffsetTable::index_for(const void* p) const {
88 char* pc = (char*)p;
89 assert(pc >= (char*)_reserved.start() &&
90 pc < (char*)_reserved.end(),
91 "p (" PTR_FORMAT ") not in reserved [" PTR_FORMAT ", " PTR_FORMAT ")",
92 p2i(p), p2i(_reserved.start()), p2i(_reserved.end()));
93 size_t result = index_for_raw(p);
94 check_index(result, "bad index from address");
95 return result;
96 }
97
98 inline HeapWord* G1BlockOffsetTable::address_for_index(size_t index) const {
99 check_index(index, "index out of range");
100 HeapWord* result = address_for_index_raw(index);
101 assert(result >= _reserved.start() && result < _reserved.end(),
102 "bad address from index result " PTR_FORMAT
103 " _reserved.start() " PTR_FORMAT " _reserved.end() " PTR_FORMAT,
104 p2i(result), p2i(_reserved.start()), p2i(_reserved.end()));
105 return result;
106 }
107
108 inline size_t G1BlockOffsetTablePart::block_size(const HeapWord* p) const {
109 return _hr->block_size(p);
110 }
111
112 inline HeapWord* G1BlockOffsetTablePart::block_at_or_preceding(const void* addr,
113 bool has_max_index,
114 size_t max_index) const {
115 assert(_object_can_span || _bot->offset_array(_bot->index_for(_hr->bottom())) == 0,
116 "Object crossed region boundary, found offset %u instead of 0",
117 (uint) _bot->offset_array(_bot->index_for(_hr->bottom())));
118 size_t index = _bot->index_for(addr);
119 // We must make sure that the offset table entry we use is valid. If
120 // "addr" is past the end, start at the last known one and go forward.
121 if (has_max_index) {
122 index = MIN2(index, max_index);
123 }
124 HeapWord* q = _bot->address_for_index(index);
125
126 uint offset = _bot->offset_array(index); // Extend u_char to uint.
127 while (offset >= BOTConstants::N_words) {
128 // The excess of the offset from N_words indicates a power of Base
129 // to go back by.
130 size_t n_cards_back = BOTConstants::entry_to_cards_back(offset);
131 q -= (BOTConstants::N_words * n_cards_back);
132 index -= n_cards_back;
133 offset = _bot->offset_array(index);
134 }
135 assert(offset < BOTConstants::N_words, "offset too large");
136 q -= offset;
137 return q;
138 }
139
140 inline HeapWord* G1BlockOffsetTablePart::forward_to_block_containing_addr_const(HeapWord* q, HeapWord* n,
141 const void* addr) const {
142 if (addr >= _hr->top()) return _hr->top();
143 while (n <= addr) {
144 q = n;
145 oop obj = oop(q);
146 if (obj->klass_or_null_acquire() == NULL) {
147 return q;
148 }
149 n += block_size(q);
150 }
151 assert(q <= n, "wrong order for q and addr");
152 assert(addr < n, "wrong order for addr and n");
153 return q;
154 }
155
156 inline HeapWord* G1BlockOffsetTablePart::forward_to_block_containing_addr(HeapWord* q,
157 const void* addr) {
158 if (oop(q)->klass_or_null_acquire() == NULL) {
159 return q;
160 }
161 HeapWord* n = q + block_size(q);
162 // In the normal case, where the query "addr" is a card boundary, and the
163 // offset table chunks are the same size as cards, the block starting at
164 // "q" will contain addr, so the test below will fail, and we'll fall
165 // through quickly.
166 if (n <= addr) {
167 q = forward_to_block_containing_addr_slow(q, n, addr);
168 }
169 assert(q <= addr, "wrong order for current and arg");
170 return q;
171 }
172
173 #endif // SHARE_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
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