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#include "config.h"
27#include "PageAllocationAligned.h"
28
29namespace WTF {
30
31PageAllocationAligned PageAllocationAligned::allocate(size_t size, size_t alignment, OSAllocator::Usage usage, bool writable)
32{
33 ASSERT(isPageAligned(size));
34 ASSERT(isPageAligned(alignment));
35 ASSERT(isPowerOfTwo(alignment));
36 ASSERT(size >= alignment);
37 size_t alignmentMask = alignment - 1;
38
39#if OS(DARWIN)
40 int flags = VM_FLAGS_ANYWHERE;
41 if (usage != OSAllocator::UnknownUsage)
42 flags |= usage;
43 int protection = PROT_READ;
44 if (writable)
45 protection |= PROT_WRITE;
46
47 vm_address_t address = 0;
48 vm_map(current_task(), &address, size, alignmentMask, flags, MEMORY_OBJECT_NULL, 0, FALSE, protection, PROT_READ | PROT_WRITE, VM_INHERIT_DEFAULT);
49 return PageAllocationAligned(reinterpret_cast<void*>(address), size);
50#else
51 size_t alignmentDelta = alignment - pageSize();
52
53 // Resererve with suffcient additional VM to correctly align.
54 size_t reservationSize = size + alignmentDelta;
55 void* reservationBase = OSAllocator::reserveUncommitted(reservationSize, usage, writable);
56
57 // Select an aligned region within the reservation and commit.
58 void* alignedBase = reinterpret_cast<uintptr_t>(reservationBase) & alignmentMask
59 ? reinterpret_cast<void*>((reinterpret_cast<uintptr_t>(reservationBase) & ~alignmentMask) + alignment)
60 : reservationBase;
61 OSAllocator::commit(alignedBase, size, writable, executable: false);
62
63 return PageAllocationAligned(alignedBase, size, reservationBase, reservationSize);
64#endif
65}
66
67void PageAllocationAligned::deallocate()
68{
69 // Clear base & size before calling release; if this is *inside* allocation
70 // then we won't be able to clear then after deallocating the memory.
71 PageAllocationAligned tmp;
72 std::swap(a&: tmp, b&: *this);
73
74 ASSERT(tmp);
75 ASSERT(!*this);
76
77#if OS(DARWIN)
78 vm_deallocate(current_task(), reinterpret_cast<vm_address_t>(tmp.realBase()), tmp.realSize());
79#else
80 ASSERT(tmp.m_reservation.contains(tmp.realBase(), tmp.realSize()));
81 OSAllocator::decommitAndRelease(releaseBase: tmp.m_reservation.realBase(), releaseSize: tmp.m_reservation.realSize(),
82 decommitBase: tmp.realBase(), decommitSize: tmp.realSize());
83#endif
84}
85
86} // namespace WTF
87

source code of qtdeclarative/src/3rdparty/masm/wtf/PageAllocationAligned.cpp