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1 // Copyright 2013 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "mojo/system/memory.h" | |
6 | |
7 #include <limits> | |
8 | |
9 #include "base/logging.h" | |
10 #include "build/build_config.h" | |
11 | |
12 namespace mojo { | |
13 namespace system { | |
14 namespace internal { | |
15 | |
16 template <size_t alignment> | |
17 bool IsAligned(const void* pointer) { | |
18 return reinterpret_cast<uintptr_t>(pointer) % alignment == 0; | |
19 } | |
20 | |
21 // MSVS (2010, 2013) sometimes (on the stack) aligns, e.g., |int64_t|s (for | |
22 // which |__alignof(int64_t)| is 8) to 4-byte boundaries. http://goo.gl/Y2n56T | |
23 #if defined(COMPILER_MSVC) && defined(ARCH_CPU_32_BITS) | |
24 template <> | |
25 bool IsAligned<8>(const void* pointer) { | |
26 return reinterpret_cast<uintptr_t>(pointer) % 4 == 0; | |
27 } | |
28 #endif | |
29 | |
30 template <size_t size, size_t alignment> | |
31 void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer(const void* pointer) { | |
32 CHECK(pointer && IsAligned<alignment>(pointer)); | |
33 } | |
34 | |
35 // Explicitly instantiate the sizes we need. Add instantiations as needed. | |
36 template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<1, 1>(const void*); | |
37 template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<4, 4>(const void*); | |
38 template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<8, 4>(const void*); | |
39 template void MOJO_SYSTEM_IMPL_EXPORT CheckUserPointer<8, 8>(const void*); | |
40 | |
41 template <size_t size, size_t alignment> | |
42 void MOJO_SYSTEM_IMPL_EXPORT | |
43 CheckUserPointerWithCount(const void* pointer, size_t count) { | |
44 CHECK_LE(count, std::numeric_limits<size_t>::max() / size); | |
45 CHECK(count == 0 || (pointer && IsAligned<alignment>(pointer))); | |
46 } | |
47 | |
48 // Explicitly instantiate the sizes we need. Add instantiations as needed. | |
49 template void MOJO_SYSTEM_IMPL_EXPORT | |
50 CheckUserPointerWithCount<1, 1>(const void*, size_t); | |
51 template void MOJO_SYSTEM_IMPL_EXPORT | |
52 CheckUserPointerWithCount<4, 4>(const void*, size_t); | |
53 template void MOJO_SYSTEM_IMPL_EXPORT | |
54 CheckUserPointerWithCount<8, 4>(const void*, size_t); | |
55 template void MOJO_SYSTEM_IMPL_EXPORT | |
56 CheckUserPointerWithCount<8, 8>(const void*, size_t); | |
57 | |
58 template <size_t alignment> | |
59 void CheckUserPointerWithSize(const void* pointer, size_t size) { | |
60 // TODO(vtl): If running in kernel mode, do a full verification. For now, just | |
61 // check that it's non-null and aligned. (A faster user mode implementation is | |
62 // also possible if this check is skipped.) | |
63 CHECK(size == 0 || (!!pointer && internal::IsAligned<alignment>(pointer))); | |
64 } | |
65 | |
66 // Explicitly instantiate the sizes we need. Add instantiations as needed. | |
67 template void MOJO_SYSTEM_IMPL_EXPORT | |
68 CheckUserPointerWithSize<1>(const void*, size_t); | |
69 template void MOJO_SYSTEM_IMPL_EXPORT | |
70 CheckUserPointerWithSize<4>(const void*, size_t); | |
71 // Whereas the other |Check...()| functions are usually used with integral typs | |
72 // or arrays of integral types, this one is used with Options structs for which | |
73 // alignment has been explicitly been specified (using |MOJO_ALIGNAS()|), which | |
74 // MSVS *does* respect. | |
75 #if defined(COMPILER_MSVC) && defined(ARCH_CPU_32_BITS) | |
76 template <> | |
77 void MOJO_SYSTEM_IMPL_EXPORT | |
78 CheckUserPointerWithSize<8>(const void* pointer, size_t size) { | |
79 CHECK(size == 0 || | |
80 (!!pointer && reinterpret_cast<uintptr_t>(pointer) % 8 == 0)); | |
81 } | |
82 #else | |
83 template void MOJO_SYSTEM_IMPL_EXPORT | |
84 CheckUserPointerWithSize<8>(const void*, size_t); | |
85 #endif | |
86 | |
87 } // namespace internal | |
88 } // namespace system | |
89 } // namespace mojo | |
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