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1 /* | |
2 * Copyright (C) 2010 Apple Inc. All rights reserved. | |
3 * | |
4 * Redistribution and use in source and binary forms, with or without | |
5 * modification, are permitted provided that the following conditions | |
6 * are met: | |
7 * 1. Redistributions of source code must retain the above copyright | |
8 * notice, this list of conditions and the following disclaimer. | |
9 * 2. Redistributions in binary form must reproduce the above copyright | |
10 * notice, this list of conditions and the following disclaimer in the | |
11 * documentation and/or other materials provided with the distribution. | |
12 * | |
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' | |
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, | |
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS | |
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF | |
23 * THE POSSIBILITY OF SUCH DAMAGE. | |
24 */ | |
25 | |
26 #ifndef OSAllocator_h | |
27 #define OSAllocator_h | |
28 | |
29 #include <algorithm> | |
30 #include <wtf/UnusedParam.h> | |
31 #include <wtf/VMTags.h> | |
32 | |
33 namespace WTF { | |
34 | |
35 class OSAllocator { | |
36 public: | |
37 enum Usage { | |
38 UnknownUsage = -1, | |
39 FastMallocPages = VM_TAG_FOR_TCMALLOC_MEMORY, | |
40 JSGCHeapPages = VM_TAG_FOR_COLLECTOR_MEMORY, | |
41 JSVMStackPages = VM_TAG_FOR_REGISTERFILE_MEMORY, | |
42 JSJITCodePages = VM_TAG_FOR_EXECUTABLEALLOCATOR_MEMORY, | |
43 }; | |
44 | |
45 // These methods are symmetric; reserveUncommitted allocates VM in an uncomm
itted state, | |
46 // releaseDecommitted should be called on a region of VM allocated by a sing
le reservation, | |
47 // the memory must all currently be in a decommitted state. | |
48 static void* reserveUncommitted(size_t, Usage = UnknownUsage, bool writable
= true, bool executable = false, bool includesGuardPages = false); | |
49 WTF_EXPORT_PRIVATE static void releaseDecommitted(void*, size_t); | |
50 | |
51 // These methods are symmetric; they commit or decommit a region of VM (unco
mmitted VM should | |
52 // never be accessed, since the OS may not have attached physical memory for
these regions). | |
53 // Clients should only call commit on uncommitted regions and decommit on co
mmitted regions. | |
54 static void commit(void*, size_t, bool writable, bool executable); | |
55 static void decommit(void*, size_t); | |
56 | |
57 // These methods are symmetric; reserveAndCommit allocates VM in an committe
d state, | |
58 // decommitAndRelease should be called on a region of VM allocated by a sing
le reservation, | |
59 // the memory must all currently be in a committed state. | |
60 WTF_EXPORT_PRIVATE static void* reserveAndCommit(size_t, Usage = UnknownUsag
e, bool writable = true, bool executable = false, bool includesGuardPages = fals
e); | |
61 static void decommitAndRelease(void* base, size_t size); | |
62 | |
63 // These methods are akin to reserveAndCommit/decommitAndRelease, above - ho
wever rather than | |
64 // committing/decommitting the entire region additional parameters allow a s
ubregion to be | |
65 // specified. | |
66 static void* reserveAndCommit(size_t reserveSize, size_t commitSize, Usage =
UnknownUsage, bool writable = true, bool executable = false); | |
67 static void decommitAndRelease(void* releaseBase, size_t releaseSize, void*
decommitBase, size_t decommitSize); | |
68 | |
69 // Reallocate an existing, committed allocation. | |
70 // The prior allocation must be fully comitted, and the new size will also b
e fully committed. | |
71 // This interface is provided since it may be possible to optimize this oper
ation on some platforms. | |
72 template<typename T> | |
73 static T* reallocateCommitted(T*, size_t oldSize, size_t newSize, Usage = Un
knownUsage, bool writable = true, bool executable = false); | |
74 }; | |
75 | |
76 inline void* OSAllocator::reserveAndCommit(size_t reserveSize, size_t commitSize
, Usage usage, bool writable, bool executable) | |
77 { | |
78 void* base = reserveUncommitted(reserveSize, usage, writable, executable); | |
79 commit(base, commitSize, writable, executable); | |
80 return base; | |
81 } | |
82 | |
83 inline void OSAllocator::decommitAndRelease(void* releaseBase, size_t releaseSiz
e, void* decommitBase, size_t decommitSize) | |
84 { | |
85 ASSERT(decommitBase >= releaseBase && (static_cast<char*>(decommitBase) + de
commitSize) <= (static_cast<char*>(releaseBase) + releaseSize)); | |
86 #if OS(WINCE) | |
87 // On most platforms we can actually skip this final decommit; releasing the
VM will | |
88 // implicitly decommit any physical memory in the region. This is not true o
n WINCE. | |
89 decommit(decommitBase, decommitSize); | |
90 #else | |
91 UNUSED_PARAM(decommitBase); | |
92 UNUSED_PARAM(decommitSize); | |
93 #endif | |
94 releaseDecommitted(releaseBase, releaseSize); | |
95 } | |
96 | |
97 inline void OSAllocator::decommitAndRelease(void* base, size_t size) | |
98 { | |
99 decommitAndRelease(base, size, base, size); | |
100 } | |
101 | |
102 template<typename T> | |
103 inline T* OSAllocator::reallocateCommitted(T* oldBase, size_t oldSize, size_t ne
wSize, Usage usage, bool writable, bool executable) | |
104 { | |
105 void* newBase = reserveAndCommit(newSize, usage, writable, executable); | |
106 memcpy(newBase, oldBase, std::min(oldSize, newSize)); | |
107 decommitAndRelease(oldBase, oldSize); | |
108 return static_cast<T*>(newBase); | |
109 } | |
110 | |
111 } // namespace WTF | |
112 | |
113 using WTF::OSAllocator; | |
114 | |
115 #endif // OSAllocator_h | |
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