random/internal/platform.h

0001 // Copyright 2017 The Abseil Authors.
0002 //
0003 // Licensed under the Apache License, Version 2.0 (the "License");
0004 // you may not use this file except in compliance with the License.
0005 // You may obtain a copy of the License at
0006 //
0007 //      https://www.apache.org/licenses/LICENSE-2.0
0008 //
0009 // Unless required by applicable law or agreed to in writing, software
0010 // distributed under the License is distributed on an "AS IS" BASIS,
0011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0012 // See the License for the specific language governing permissions and
0013 // limitations under the License.
0014
0015 #ifndef ABSL_RANDOM_INTERNAL_PLATFORM_H_
0016 #define ABSL_RANDOM_INTERNAL_PLATFORM_H_
0017
0018 // HERMETIC NOTE: The randen_hwaes target must not introduce duplicate
0019 // symbols from arbitrary system and other headers, since it may be built
0020 // with different flags from other targets, using different levels of
0021 // optimization, potentially introducing ODR violations.
0022
0023 // -----------------------------------------------------------------------------
0024 // Platform Feature Checks
0025 // -----------------------------------------------------------------------------
0026
0027 // Currently supported operating systems and associated preprocessor
0028 // symbols:
0029 //
0030 //   Linux and Linux-derived           __linux__
0031 //   Android                           __ANDROID__ (implies __linux__)
0032 //   Linux (non-Android)               __linux__ && !__ANDROID__
0033 //   Darwin (macOS and iOS)            __APPLE__
0034 //   Akaros (http://akaros.org)        __ros__
0035 //   Windows                           _WIN32
0036 //   NaCL                              __native_client__
0037 //   AsmJS                             __asmjs__
0038 //   WebAssembly                       __wasm__
0039 //   Fuchsia                           __Fuchsia__
0040 //
0041 // Note that since Android defines both __ANDROID__ and __linux__, one
0042 // may probe for either Linux or Android by simply testing for __linux__.
0043 //
0044 // NOTE: For __APPLE__ platforms, we use #include <TargetConditionals.h>
0045 // to distinguish os variants.
0046 //
0047 // http://nadeausoftware.com/articles/2012/01/c_c_tip_how_use_compiler_predefined_macros_detect_operating_system
0048
0049 #if defined(__APPLE__)
0050 #include <TargetConditionals.h>
0051 #endif
0052
0053 // -----------------------------------------------------------------------------
0054 // Architecture Checks
0055 // -----------------------------------------------------------------------------
0056
0057 // These preprocessor directives are trying to determine CPU architecture,
0058 // including necessary headers to support hardware AES.
0059 //
0060 // ABSL_ARCH_{X86/PPC/ARM} macros determine the platform.
0061 #if defined(__x86_64__) || defined(__x86_64) || defined(_M_AMD64) || \
0062     defined(_M_X64)
0063 #define ABSL_ARCH_X86_64
0064 #elif defined(__i386) || defined(_M_IX86)
0065 #define ABSL_ARCH_X86_32
0066 #elif defined(__aarch64__) || defined(__arm64__) || defined(_M_ARM64)
0067 #define ABSL_ARCH_AARCH64
0068 #elif defined(__arm__) || defined(__ARMEL__) || defined(_M_ARM)
0069 #define ABSL_ARCH_ARM
0070 #elif defined(__powerpc64__) || defined(__PPC64__) || defined(__powerpc__) || \
0071     defined(__ppc__) || defined(__PPC__)
0072 #define ABSL_ARCH_PPC
0073 #else
0074 // Unsupported architecture.
0075 //  * https://sourceforge.net/p/predef/wiki/Architectures/
0076 //  * https://msdn.microsoft.com/en-us/library/b0084kay.aspx
0077 //  * for gcc, clang: "echo | gcc -E -dM -"
0078 #endif
0079
0080 // -----------------------------------------------------------------------------
0081 // Attribute Checks
0082 // -----------------------------------------------------------------------------
0083
0084 // ABSL_RANDOM_INTERNAL_RESTRICT annotates whether pointers may be considered
0085 // to be unaliased.
0086 #if defined(__clang__) || defined(__GNUC__)
0087 #define ABSL_RANDOM_INTERNAL_RESTRICT __restrict__
0088 #elif defined(_MSC_VER)
0089 #define ABSL_RANDOM_INTERNAL_RESTRICT __restrict
0090 #else
0091 #define ABSL_RANDOM_INTERNAL_RESTRICT
0092 #endif
0093
0094 // ABSL_HAVE_ACCELERATED_AES indicates whether the currently active compiler
0095 // flags (e.g. -maes) allow using hardware accelerated AES instructions, which
0096 // implies us assuming that the target platform supports them.
0097 #define ABSL_HAVE_ACCELERATED_AES 0
0098
0099 #if defined(ABSL_ARCH_X86_64)
0100
0101 #if defined(__AES__) || defined(__AVX__)
0102 #undef ABSL_HAVE_ACCELERATED_AES
0103 #define ABSL_HAVE_ACCELERATED_AES 1
0104 #endif
0105
0106 #elif defined(ABSL_ARCH_PPC)
0107
0108 // Rely on VSX and CRYPTO extensions for vcipher on PowerPC.
0109 #if (defined(__VEC__) || defined(__ALTIVEC__)) && defined(__VSX__) && \
0110     defined(__CRYPTO__)
0111 #undef ABSL_HAVE_ACCELERATED_AES
0112 #define ABSL_HAVE_ACCELERATED_AES 1
0113 #endif
0114
0115 #elif defined(ABSL_ARCH_ARM) || defined(ABSL_ARCH_AARCH64)
0116
0117 // http://infocenter.arm.com/help/topic/com.arm.doc.ihi0053c/IHI0053C_acle_2_0.pdf
0118 // Rely on NEON+CRYPTO extensions for ARM.
0119 #if defined(__ARM_NEON) && defined(__ARM_FEATURE_CRYPTO)
0120 #undef ABSL_HAVE_ACCELERATED_AES
0121 #define ABSL_HAVE_ACCELERATED_AES 1
0122 #endif
0123
0124 #endif
0125
0126 // NaCl does not allow AES.
0127 #if defined(__native_client__)
0128 #undef ABSL_HAVE_ACCELERATED_AES
0129 #define ABSL_HAVE_ACCELERATED_AES 0
0130 #endif
0131
0132 // ABSL_RANDOM_INTERNAL_AES_DISPATCH indicates whether the currently active
0133 // platform has, or should use run-time dispatch for selecting the
0134 // accelerated Randen implementation.
0135 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 0
0136
0137 #if defined(ABSL_ARCH_X86_64)
0138 // Dispatch is available on x86_64
0139 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
0140 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1
0141 #elif defined(__linux__) && defined(ABSL_ARCH_PPC)
0142 // Or when running linux PPC
0143 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
0144 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1
0145 #elif defined(__linux__) && defined(ABSL_ARCH_AARCH64)
0146 // Or when running linux AArch64
0147 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
0148 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1
0149 #elif defined(__linux__) && defined(ABSL_ARCH_ARM) && (__ARM_ARCH >= 8)
0150 // Or when running linux ARM v8 or higher.
0151 // (This captures a lot of Android configurations.)
0152 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
0153 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1
0154 #endif
0155
0156 // NaCl does not allow dispatch.
0157 #if defined(__native_client__)
0158 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
0159 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 0
0160 #endif
0161
0162 // iOS does not support dispatch, even on x86, since applications
0163 // should be bundled as fat binaries, with a different build tailored for
0164 // each specific supported platform/architecture.
0165 #if (defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) || \
0166     (defined(TARGET_OS_IPHONE_SIMULATOR) && TARGET_OS_IPHONE_SIMULATOR)
0167 #undef ABSL_RANDOM_INTERNAL_AES_DISPATCH
0168 #define ABSL_RANDOM_INTERNAL_AES_DISPATCH 0
0169 #endif
0170
0171 #endif  // ABSL_RANDOM_INTERNAL_PLATFORM_H_