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 uncommitted state, |
46 | // releaseDecommitted should be called on a region of VM allocated by a single 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); |
49 | WTF_EXPORT_PRIVATE static void releaseDecommitted(void*, size_t); |
50 | |
51 | // These methods are symmetric; they commit or decommit a region of VM (uncommitted 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 committed 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 committed state, |
58 | // decommitAndRelease should be called on a region of VM allocated by a single reservation, |
59 | // the memory must all currently be in a committed state. |
60 | WTF_EXPORT_PRIVATE static void* reserveAndCommit(size_t, Usage = UnknownUsage, bool writable = true, bool executable = false, bool includesGuardPages = false); |
61 | static void decommitAndRelease(void* base, size_t size); |
62 | |
63 | // These methods are akin to reserveAndCommit/decommitAndRelease, above - however rather than |
64 | // committing/decommitting the entire region additional parameters allow a subregion 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 be fully committed. |
71 | // This interface is provided since it may be possible to optimize this operation on some platforms. |
72 | template<typename T> |
73 | static T* reallocateCommitted(T*, size_t oldSize, size_t newSize, Usage = UnknownUsage, bool writable = true, bool executable = false); |
74 | |
75 | static bool canAllocateExecutableMemory(); |
76 | |
77 | #if defined(Q_OS_INTEGRITY) |
78 | static void setMemoryAttributes(void* addr, size_t size, bool writable, bool executable); |
79 | #endif |
80 | }; |
81 | |
82 | inline void* OSAllocator::reserveAndCommit(size_t reserveSize, size_t commitSize, Usage usage, bool writable, bool executable) |
83 | { |
84 | void* base = reserveUncommitted(reserveSize, usage, writable, executable); |
85 | commit(base, commitSize, writable, executable); |
86 | return base; |
87 | } |
88 | |
89 | inline void OSAllocator::decommitAndRelease(void* releaseBase, size_t releaseSize, void* decommitBase, size_t decommitSize) |
90 | { |
91 | ASSERT(decommitBase >= releaseBase && (static_cast<char*>(decommitBase) + decommitSize) <= (static_cast<char*>(releaseBase) + releaseSize)); |
92 | #if OS(WINCE) |
93 | // On most platforms we can actually skip this final decommit; releasing the VM will |
94 | // implicitly decommit any physical memory in the region. This is not true on WINCE. |
95 | decommit(decommitBase, decommitSize); |
96 | #else |
97 | UNUSED_PARAM(decommitBase); |
98 | UNUSED_PARAM(decommitSize); |
99 | #endif |
100 | releaseDecommitted(releaseBase, releaseSize); |
101 | } |
102 | |
103 | inline void OSAllocator::decommitAndRelease(void* base, size_t size) |
104 | { |
105 | decommitAndRelease(releaseBase: base, releaseSize: size, decommitBase: base, decommitSize: size); |
106 | } |
107 | |
108 | template<typename T> |
109 | inline T* OSAllocator::reallocateCommitted(T* oldBase, size_t oldSize, size_t newSize, Usage usage, bool writable, bool executable) |
110 | { |
111 | void* newBase = reserveAndCommit(newSize, usage, writable, executable); |
112 | memcpy(newBase, oldBase, std::min(a: oldSize, b: newSize)); |
113 | decommitAndRelease(oldBase, oldSize); |
114 | return static_cast<T*>(newBase); |
115 | } |
116 | |
117 | } // namespace WTF |
118 | |
119 | using WTF::OSAllocator; |
120 | |
121 | #endif // OSAllocator_h |
122 | |