Thu, 13 Jun 2013 22:02:40 -0700
8014431: cleanup warnings indicated by the -Wunused-value compiler option on linux
Reviewed-by: dholmes, coleenp
Contributed-by: jeremymanson@google.com, calvin.cheung@oracle.com
1 /*
2 * Copyright (c) 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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
25 #include "precompiled.hpp"
26 #include "memory/allocation.hpp"
27 #include "memory/metachunk.hpp"
28 #include "utilities/copy.hpp"
29 #include "utilities/debug.hpp"
31 class VirtualSpaceNode;
32 //
33 // Future modification
34 //
35 // The Metachunk can conceivable be replaced by the Chunk in
36 // allocation.hpp. Note that the latter Chunk is the space for
37 // allocation (allocations from the chunk are out of the space in
38 // the Chunk after the header for the Chunk) where as Metachunks
39 // point to space in a VirtualSpace. To replace Metachunks with
40 // Chunks, change Chunks so that they can be allocated out of a VirtualSpace.
42 const size_t metadata_chunk_initialize = 0xf7f7f7f7;
44 size_t Metachunk::_overhead =
45 Chunk::aligned_overhead_size(sizeof(Metachunk)) / BytesPerWord;
47 // Metachunk methods
49 Metachunk::Metachunk(size_t word_size,
50 VirtualSpaceNode* container) :
51 _word_size(word_size),
52 _bottom(NULL),
53 _end(NULL),
54 _top(NULL),
55 _next(NULL),
56 _prev(NULL),
57 _container(container)
58 {
59 _bottom = (MetaWord*)this;
60 _top = (MetaWord*)this + _overhead;
61 _end = (MetaWord*)this + word_size;
62 #ifdef ASSERT
63 set_is_free(false);
64 size_t data_word_size = pointer_delta(end(),
65 top(),
66 sizeof(MetaWord));
67 Copy::fill_to_words((HeapWord*) top(),
68 data_word_size,
69 metadata_chunk_initialize);
70 #endif
71 }
73 MetaWord* Metachunk::allocate(size_t word_size) {
74 MetaWord* result = NULL;
75 // If available, bump the pointer to allocate.
76 if (free_word_size() >= word_size) {
77 result = _top;
78 _top = _top + word_size;
79 }
80 return result;
81 }
83 // _bottom points to the start of the chunk including the overhead.
84 size_t Metachunk::used_word_size() const {
85 return pointer_delta(_top, _bottom, sizeof(MetaWord));
86 }
88 size_t Metachunk::free_word_size() const {
89 return pointer_delta(_end, _top, sizeof(MetaWord));
90 }
92 size_t Metachunk::capacity_word_size() const {
93 return pointer_delta(_end, _bottom, sizeof(MetaWord));
94 }
96 void Metachunk::print_on(outputStream* st) const {
97 st->print_cr("Metachunk:"
98 " bottom " PTR_FORMAT " top " PTR_FORMAT
99 " end " PTR_FORMAT " size " SIZE_FORMAT,
100 bottom(), top(), end(), word_size());
101 if (Verbose) {
102 st->print_cr(" used " SIZE_FORMAT " free " SIZE_FORMAT,
103 used_word_size(), free_word_size());
104 }
105 }
107 #ifndef PRODUCT
108 void Metachunk::mangle() {
109 // Mangle the payload of the chunk and not the links that
110 // maintain list of chunks.
111 HeapWord* start = (HeapWord*)(bottom() + overhead());
112 size_t word_size = capacity_word_size() - overhead();
113 Copy::fill_to_words(start, word_size, metadata_chunk_initialize);
114 }
115 #endif // PRODUCT
117 void Metachunk::verify() {
118 #ifdef ASSERT
119 // Cannot walk through the blocks unless the blocks have
120 // headers with sizes.
121 assert(_bottom <= _top &&
122 _top <= _end,
123 "Chunk has been smashed");
124 #endif
125 return;
126 }