abseil-cpp/absl/random/internal/platform.h
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1 // Copyright 2017 The Abseil Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #ifndef ABSL_RANDOM_INTERNAL_PLATFORM_H_
16 #define ABSL_RANDOM_INTERNAL_PLATFORM_H_
17 
18 // HERMETIC NOTE: The randen_hwaes target must not introduce duplicate
19 // symbols from arbitrary system and other headers, since it may be built
20 // with different flags from other targets, using different levels of
21 // optimization, potentially introducing ODR violations.
22 
23 // -----------------------------------------------------------------------------
24 // Platform Feature Checks
25 // -----------------------------------------------------------------------------
26 
27 // Currently supported operating systems and associated preprocessor
28 // symbols:
29 //
30 // Linux and Linux-derived __linux__
31 // Android __ANDROID__ (implies __linux__)
32 // Linux (non-Android) __linux__ && !__ANDROID__
33 // Darwin (macOS and iOS) __APPLE__
34 // Akaros (http://akaros.org) __ros__
35 // Windows _WIN32
36 // NaCL __native_client__
37 // AsmJS __asmjs__
38 // WebAssembly __wasm__
39 // Fuchsia __Fuchsia__
40 //
41 // Note that since Android defines both __ANDROID__ and __linux__, one
42 // may probe for either Linux or Android by simply testing for __linux__.
43 //
44 // NOTE: For __APPLE__ platforms, we use #include <TargetConditionals.h>
45 // to distinguish os variants.
46 //
47 // http://nadeausoftware.com/articles/2012/01/c_c_tip_how_use_compiler_predefined_macros_detect_operating_system
48 
49 #if defined(__APPLE__)
50 #include <TargetConditionals.h>
51 #endif
52 
53 // -----------------------------------------------------------------------------
54 // Architecture Checks
55 // -----------------------------------------------------------------------------
56 
57 // These preprocessor directives are trying to determine CPU architecture,
58 // including necessary headers to support hardware AES.
59 //
60 // ABSL_ARCH_{X86/PPC/ARM} macros determine the platform.
61 #if defined(__x86_64__) || defined(__x86_64) || defined(_M_AMD64) || \
62  defined(_M_X64)
63 #define ABSL_ARCH_X86_64
64 #elif defined(__i386) || defined(_M_IX86)
65 #define ABSL_ARCH_X86_32
66 #elif defined(__aarch64__) || defined(__arm64__) || defined(_M_ARM64)
67 #define ABSL_ARCH_AARCH64
68 #elif defined(__arm__) || defined(__ARMEL__) || defined(_M_ARM)
69 #define ABSL_ARCH_ARM
70 #elif defined(__powerpc64__) || defined(__PPC64__) || defined(__powerpc__) || \
71  defined(__ppc__) || defined(__PPC__)
72 #define ABSL_ARCH_PPC
73 #else
74 // Unsupported architecture.
75 // * https://sourceforge.net/p/predef/wiki/Architectures/
76 // * https://msdn.microsoft.com/en-us/library/b0084kay.aspx
77 // * for gcc, clang: "echo | gcc -E -dM -"
78 #endif
79 
80 // -----------------------------------------------------------------------------
81 // Attribute Checks
82 // -----------------------------------------------------------------------------
83 
84 // ABSL_RANDOM_INTERNAL_RESTRICT annotates whether pointers may be considered
85 // to be unaliased.
86 #if defined(__clang__) || defined(__GNUC__)
87 #define ABSL_RANDOM_INTERNAL_RESTRICT __restrict__
88 #elif defined(_MSC_VER)
89 #define ABSL_RANDOM_INTERNAL_RESTRICT __restrict
90 #else
91 #define ABSL_RANDOM_INTERNAL_RESTRICT
92 #endif
93 
94 // ABSL_HAVE_ACCELERATED_AES indicates whether the currently active compiler
95 // flags (e.g. -maes) allow using hardware accelerated AES instructions, which
96 // implies us assuming that the target platform supports them.
97 #define ABSL_HAVE_ACCELERATED_AES 0
98 
99 #if defined(ABSL_ARCH_X86_64)
100 
101 #if defined(__AES__) || defined(__AVX__)
102 #undef ABSL_HAVE_ACCELERATED_AES
103 #define ABSL_HAVE_ACCELERATED_AES 1
104 #endif
105 
106 #elif defined(ABSL_ARCH_PPC)
107 
108 // Rely on VSX and CRYPTO extensions for vcipher on PowerPC.
109 #if (defined(__VEC__) || defined(__ALTIVEC__)) && defined(__VSX__) && \
110  defined(__CRYPTO__)
111 #undef ABSL_HAVE_ACCELERATED_AES
112 #define ABSL_HAVE_ACCELERATED_AES 1
113 #endif
114 
115 #elif defined(ABSL_ARCH_ARM) || defined(ABSL_ARCH_AARCH64)
116 
117 // http://infocenter.arm.com/help/topic/com.arm.doc.ihi0053c/IHI0053C_acle_2_0.pdf
118 // Rely on NEON+CRYPTO extensions for ARM.
119 #if defined(__ARM_NEON) && defined(__ARM_FEATURE_CRYPTO)
120 #undef ABSL_HAVE_ACCELERATED_AES
121 #define ABSL_HAVE_ACCELERATED_AES 1
122 #endif
123 
124 #endif
125 
126 // NaCl does not allow AES.
127 #if defined(__native_client__)
128 #undef ABSL_HAVE_ACCELERATED_AES
129 #define ABSL_HAVE_ACCELERATED_AES 0
130 #endif
131 
132 // ABSL_RANDOM_INTERNAL_AES_DISPATCH indicates whether the currently active
133 // platform has, or should use run-time dispatch for selecting the
134 // acclerated Randen implementation.
135 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 0
136 
137 #if defined(ABSL_ARCH_X86_64)
138 // Dispatch is available on x86_64
139 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
140 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1
141 #elif defined(__linux__) && defined(ABSL_ARCH_PPC)
142 // Or when running linux PPC
143 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
144 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1
145 #elif defined(__linux__) && defined(ABSL_ARCH_AARCH64)
146 // Or when running linux AArch64
147 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
148 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1
149 #elif defined(__linux__) && defined(ABSL_ARCH_ARM) && (__ARM_ARCH >= 8)
150 // Or when running linux ARM v8 or higher.
151 // (This captures a lot of Android configurations.)
152 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
153 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1
154 #endif
155 
156 // NaCl does not allow dispatch.
157 #if defined(__native_client__)
158 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
159 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 0
160 #endif
161 
162 // iOS does not support dispatch, even on x86, since applications
163 // should be bundled as fat binaries, with a different build tailored for
164 // each specific supported platform/architecture.
165 #if (defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) || \
166  (defined(TARGET_OS_IPHONE_SIMULATOR) && TARGET_OS_IPHONE_SIMULATOR)
167 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
168 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 0
169 #endif
170 
171 #endif // ABSL_RANDOM_INTERNAL_PLATFORM_H_

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autogenerated on Fri May 16 2025 02:59:43