1/*
2 * Copyright (c) 2001, 2017, 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_VM_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
26#define SHARE_VM_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 "gc/shared/space.hpp"
32
33inline HeapWord* G1BlockOffsetTablePart::block_start(const void* addr) {
34  if (addr >= _space->bottom() && addr < _space->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
42inline HeapWord* G1BlockOffsetTablePart::block_start_const(const void* addr) const {
43  if (addr >= _space->bottom() && addr < _space->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
52u_char G1BlockOffsetTable::offset_array(size_t index) const {
53  check_index(index, "index out of range");
54  return _offset_array[index];
55}
56
57void G1BlockOffsetTable::set_offset_array(size_t index, u_char offset) {
58  check_index(index, "index out of range");
59  set_offset_array_raw(index, offset);
60}
61
62void G1BlockOffsetTable::set_offset_array(size_t index, HeapWord* high, HeapWord* low) {
63  check_index(index, "index out of range");
64  assert(high >= low, "addresses out of order");
65  size_t offset = pointer_delta(high, low);
66  check_offset(offset, "offset too large");
67  set_offset_array(index, (u_char)offset);
68}
69
70void G1BlockOffsetTable::set_offset_array(size_t left, size_t right, u_char offset) {
71  check_index(right, "right index out of range");
72  assert(left <= right, "indexes out of order");
73  size_t num_cards = right - left + 1;
74  memset_with_concurrent_readers(&_offset_array[left], offset, num_cards);
75}
76
77// Variant of index_for that does not check the index for validity.
78inline size_t G1BlockOffsetTable::index_for_raw(const void* p) const {
79  return pointer_delta((char*)p, _reserved.start(), sizeof(char)) >> BOTConstants::LogN;
80}
81
82inline size_t G1BlockOffsetTable::index_for(const void* p) const {
83  char* pc = (char*)p;
84  assert(pc >= (char*)_reserved.start() &&
85         pc <  (char*)_reserved.end(),
86         "p (" PTR_FORMAT ") not in reserved [" PTR_FORMAT ", " PTR_FORMAT ")",
87         p2i(p), p2i(_reserved.start()), p2i(_reserved.end()));
88  size_t result = index_for_raw(p);
89  check_index(result, "bad index from address");
90  return result;
91}
92
93inline HeapWord* G1BlockOffsetTable::address_for_index(size_t index) const {
94  check_index(index, "index out of range");
95  HeapWord* result = address_for_index_raw(index);
96  assert(result >= _reserved.start() && result < _reserved.end(),
97         "bad address from index result " PTR_FORMAT
98         " _reserved.start() " PTR_FORMAT " _reserved.end() " PTR_FORMAT,
99         p2i(result), p2i(_reserved.start()), p2i(_reserved.end()));
100  return result;
101}
102
103inline size_t G1BlockOffsetTablePart::block_size(const HeapWord* p) const {
104  return _space->block_size(p);
105}
106
107inline HeapWord* G1BlockOffsetTablePart::block_at_or_preceding(const void* addr,
108                                                               bool has_max_index,
109                                                               size_t max_index) const {
110  assert(_object_can_span || _bot->offset_array(_bot->index_for(_space->bottom())) == 0,
111         "Object crossed region boundary, found offset %u instead of 0",
112         (uint) _bot->offset_array(_bot->index_for(_space->bottom())));
113  size_t index = _bot->index_for(addr);
114  // We must make sure that the offset table entry we use is valid.  If
115  // "addr" is past the end, start at the last known one and go forward.
116  if (has_max_index) {
117    index = MIN2(index, max_index);
118  }
119  HeapWord* q = _bot->address_for_index(index);
120
121  uint offset = _bot->offset_array(index);  // Extend u_char to uint.
122  while (offset >= BOTConstants::N_words) {
123    // The excess of the offset from N_words indicates a power of Base
124    // to go back by.
125    size_t n_cards_back = BOTConstants::entry_to_cards_back(offset);
126    q -= (BOTConstants::N_words * n_cards_back);
127    index -= n_cards_back;
128    offset = _bot->offset_array(index);
129  }
130  assert(offset < BOTConstants::N_words, "offset too large");
131  q -= offset;
132  return q;
133}
134
135inline HeapWord* G1BlockOffsetTablePart::forward_to_block_containing_addr_const(HeapWord* q, HeapWord* n,
136                                                                                const void* addr) const {
137  if (addr >= _space->top()) return _space->top();
138  while (n <= addr) {
139    q = n;
140    oop obj = oop(q);
141    if (obj->klass_or_null_acquire() == NULL) {
142      return q;
143    }
144    n += block_size(q);
145  }
146  assert(q <= n, "wrong order for q and addr");
147  assert(addr < n, "wrong order for addr and n");
148  return q;
149}
150
151inline HeapWord* G1BlockOffsetTablePart::forward_to_block_containing_addr(HeapWord* q,
152                                                                          const void* addr) {
153  if (oop(q)->klass_or_null_acquire() == NULL) {
154    return q;
155  }
156  HeapWord* n = q + block_size(q);
157  // In the normal case, where the query "addr" is a card boundary, and the
158  // offset table chunks are the same size as cards, the block starting at
159  // "q" will contain addr, so the test below will fail, and we'll fall
160  // through quickly.
161  if (n <= addr) {
162    q = forward_to_block_containing_addr_slow(q, n, addr);
163  }
164  assert(q <= addr, "wrong order for current and arg");
165  return q;
166}
167
168#endif // SHARE_VM_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
169