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comparison: js/src/yarr/OSAllocator.h
js/src/yarr/OSAllocator.h
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| 1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- | |
| 2 * vim: set ts=8 sts=4 et sw=4 tw=99: | |
| 3 * | |
| 4 * ***** BEGIN LICENSE BLOCK ***** | |
| 5 * Copyright (C) 2010 Apple Inc. All rights reserved. | |
| 6 * | |
| 7 * Redistribution and use in source and binary forms, with or without | |
| 8 * modification, are permitted provided that the following conditions | |
| 9 * are met: | |
| 10 * 1. Redistributions of source code must retain the above copyright | |
| 11 * notice, this list of conditions and the following disclaimer. | |
| 12 * 2. Redistributions in binary form must reproduce the above copyright | |
| 13 * notice, this list of conditions and the following disclaimer in the | |
| 14 * documentation and/or other materials provided with the distribution. | |
| 15 * | |
| 16 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' | |
| 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, | |
| 18 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
| 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS | |
| 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF | |
| 26 * THE POSSIBILITY OF SUCH DAMAGE. | |
| 27 * | |
| 28 * ***** END LICENSE BLOCK ***** */ | |
| 29 | |
| 30 #ifndef yarr_OSAllocator_h | |
| 31 #define yarr_OSAllocator_h | |
| 32 | |
| 33 #include <stdlib.h> | |
| 34 #include "yarr/wtfbridge.h" | |
| 35 #include "assembler/wtf/VMTags.h" | |
| 36 #include "assembler/wtf/Assertions.h" | |
| 37 | |
| 38 namespace WTF { | |
| 39 | |
| 40 class OSAllocator { | |
| 41 public: | |
| 42 enum Usage { | |
| 43 UnknownUsage = -1, | |
| 44 FastMallocPages = VM_TAG_FOR_TCMALLOC_MEMORY, | |
| 45 JSGCHeapPages = VM_TAG_FOR_COLLECTOR_MEMORY, | |
| 46 JSVMStackPages = VM_TAG_FOR_REGISTERFILE_MEMORY, | |
| 47 JSJITCodePages = VM_TAG_FOR_EXECUTABLEALLOCATOR_MEMORY | |
| 48 }; | |
| 49 | |
| 50 // These methods are symmetric; reserveUncommitted allocates VM in an uncommitted state, | |
| 51 // releaseDecommitted should be called on a region of VM allocated by a single reservation, | |
| 52 // the memory must all currently be in a decommitted state. | |
| 53 static void* reserveUncommitted(size_t, Usage = UnknownUsage, bool writable = true, bool executable = false); | |
| 54 static void releaseDecommitted(void*, size_t); | |
| 55 | |
| 56 // These methods are symmetric; they commit or decommit a region of VM (uncommitted VM should | |
| 57 // never be accessed, since the OS may not have attached physical memory for these regions). | |
| 58 // Clients should only call commit on uncommitted regions and decommit on committed regions. | |
| 59 static void commit(void*, size_t, bool writable, bool executable); | |
| 60 static void decommit(void*, size_t); | |
| 61 | |
| 62 // These methods are symmetric; reserveAndCommit allocates VM in an committed state, | |
| 63 // decommitAndRelease should be called on a region of VM allocated by a single reservation, | |
| 64 // the memory must all currently be in a committed state. | |
| 65 static void* reserveAndCommit(size_t, Usage = UnknownUsage, bool writable = true, bool executable = false); | |
| 66 static void decommitAndRelease(void* base, size_t size); | |
| 67 | |
| 68 // These methods are akin to reserveAndCommit/decommitAndRelease, above - however rather than | |
| 69 // committing/decommitting the entire region additional parameters allow a subregion to be | |
| 70 // specified. | |
| 71 static void* reserveAndCommit(size_t reserveSize, size_t commitSize, Usage = UnknownUsage, bool writable = true, bool executable = false); | |
| 72 static void decommitAndRelease(void* releaseBase, size_t releaseSize, void* decommitBase, size_t decommitSize); | |
| 73 }; | |
| 74 | |
| 75 inline void* OSAllocator::reserveAndCommit(size_t reserveSize, size_t commitSize, Usage usage, bool writable, bool executable) | |
| 76 { | |
| 77 void* base = reserveUncommitted(reserveSize, usage, writable, executable); | |
| 78 commit(base, commitSize, writable, executable); | |
| 79 return base; | |
| 80 } | |
| 81 | |
| 82 inline void OSAllocator::decommitAndRelease(void* releaseBase, size_t releaseSize, void* decommitBase, size_t decommitSize) | |
| 83 { | |
| 84 ASSERT(decommitBase >= releaseBase && (static_cast<char*>(decommitBase) + decommitSize) <= (static_cast<char*>(releaseBase) + releaseSize)); | |
| 85 #if WTF_OS_WINCE || WTF_OS_SYMBIAN | |
| 86 // On most platforms we can actually skip this final decommit; releasing the VM will | |
| 87 // implicitly decommit any physical memory in the region. This is not true on WINCE. | |
| 88 // On Symbian, this makes implementation simpler and better aligned with the RChunk API | |
| 89 decommit(decommitBase, decommitSize); | |
| 90 #endif | |
| 91 releaseDecommitted(releaseBase, releaseSize); | |
| 92 } | |
| 93 | |
| 94 inline void OSAllocator::decommitAndRelease(void* base, size_t size) | |
| 95 { | |
| 96 decommitAndRelease(base, size, base, size); | |
| 97 } | |
| 98 | |
| 99 } // namespace WTF | |
| 100 | |
| 101 using WTF::OSAllocator; | |
| 102 | |
| 103 #endif /* yarr_OSAllocator_h */ |
