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Diffstat (limited to 'absl/random/internal/platform.h')
| -rw-r--r-- | absl/random/internal/platform.h | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/absl/random/internal/platform.h b/absl/random/internal/platform.h new file mode 100644 index 00000000..a5a42cbb --- /dev/null +++ b/absl/random/internal/platform.h @@ -0,0 +1,170 @@ +// Copyright 2017 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_RANDOM_INTERNAL_PLATFORM_H_ +#define ABSL_RANDOM_INTERNAL_PLATFORM_H_ + +// HERMETIC NOTE: The randen_hwaes target must not introduce duplicate +// symbols from arbitrary system and other headers, since it may be built +// with different flags from other targets, using different levels of +// optimization, potentially introducing ODR violations. + +// ----------------------------------------------------------------------------- +// Platform Feature Checks +// ----------------------------------------------------------------------------- + +// Currently supported operating systems and associated preprocessor +// symbols: +// +// Linux and Linux-derived __linux__ +// Android __ANDROID__ (implies __linux__) +// Linux (non-Android) __linux__ && !__ANDROID__ +// Darwin (macOS and iOS) __APPLE__ +// Akaros (http://akaros.org) __ros__ +// Windows _WIN32 +// NaCL __native_client__ +// AsmJS __asmjs__ +// WebAssembly __wasm__ +// Fuchsia __Fuchsia__ +// +// Note that since Android defines both __ANDROID__ and __linux__, one +// may probe for either Linux or Android by simply testing for __linux__. +// +// NOTE: For __APPLE__ platforms, we use #include <TargetConditionals.h> +// to distinguish os variants. +// +// http://nadeausoftware.com/articles/2012/01/c_c_tip_how_use_compiler_predefined_macros_detect_operating_system + +#if defined(__APPLE__) +#include <TargetConditionals.h> +#endif + +// ----------------------------------------------------------------------------- +// Architecture Checks +// ----------------------------------------------------------------------------- + +// These preprocessor directives are trying to determine CPU architecture, +// including necessary headers to support hardware AES. +// +// ABSL_ARCH_{X86/PPC/ARM} macros determine the platform. +#if defined(__x86_64__) || defined(__x86_64) || defined(_M_AMD64) || \ + defined(_M_X64) +#define ABSL_ARCH_X86_64 +#elif defined(__i386) || defined(_M_IX86) +#define ABSL_ARCH_X86_32 +#elif defined(__aarch64__) || defined(__arm64__) || defined(_M_ARM64) +#define ABSL_ARCH_AARCH64 +#elif defined(__arm__) || defined(__ARMEL__) || defined(_M_ARM) +#define ABSL_ARCH_ARM +#elif defined(__powerpc64__) || defined(__PPC64__) || defined(__powerpc__) || \ + defined(__ppc__) || defined(__PPC__) +#define ABSL_ARCH_PPC +#else +// Unsupported architecture. +// * https://sourceforge.net/p/predef/wiki/Architectures/ +// * https://msdn.microsoft.com/en-us/library/b0084kay.aspx +// * for gcc, clang: "echo | gcc -E -dM -" +#endif + +// ----------------------------------------------------------------------------- +// Attribute Checks +// ----------------------------------------------------------------------------- + +// ABSL_RANDOM_INTERNAL_RESTRICT annotates whether pointers may be considered +// to be unaliased. +#if defined(__clang__) || defined(__GNUC__) +#define ABSL_RANDOM_INTERNAL_RESTRICT __restrict__ +#elif defined(_MSC_VER) +#define ABSL_RANDOM_INTERNAL_RESTRICT __restrict +#else +#define ABSL_RANDOM_INTERNAL_RESTRICT +#endif + +// ABSL_HAVE_ACCELERATED_AES indicates whether the currently active compiler +// flags (e.g. -maes) allow using hardware accelerated AES instructions, which +// implies us assuming that the target platform supports them. +#define ABSL_HAVE_ACCELERATED_AES 0 + +#if defined(ABSL_ARCH_X86_64) + +#if defined(__AES__) || defined(__AVX__) +#undef ABSL_HAVE_ACCELERATED_AES +#define ABSL_HAVE_ACCELERATED_AES 1 +#endif + +#elif defined(ABSL_ARCH_PPC) + +// Rely on VSX and CRYPTO extensions for vcipher on PowerPC. +#if (defined(__VEC__) || defined(__ALTIVEC__)) && defined(__VSX__) && \ + defined(__CRYPTO__) +#undef ABSL_HAVE_ACCELERATED_AES +#define ABSL_HAVE_ACCELERATED_AES 1 +#endif + +#elif defined(ABSL_ARCH_ARM) || defined(ABSL_ARCH_AARCH64) + +// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0053c/IHI0053C_acle_2_0.pdf +// Rely on NEON+CRYPTO extensions for ARM. +#if defined(__ARM_NEON) && defined(__ARM_FEATURE_CRYPTO) +#undef ABSL_HAVE_ACCELERATED_AES +#define ABSL_HAVE_ACCELERATED_AES 1 +#endif + +#endif + +// NaCl does not allow AES. +#if defined(__native_client__) +#undef ABSL_HAVE_ACCELERATED_AES +#define ABSL_HAVE_ACCELERATED_AES 0 +#endif + +// ABSL_RANDOM_INTERNAL_AES_DISPATCH indicates whether the currently active +// platform has, or should use run-time dispatch for selecting the +// acclerated Randen implementation. +#define ABSL_RANDOM_INTERNAL_AES_DISPATCH 0 + +#if defined(ABSL_ARCH_X86_64) +// Dispatch is available on x86_64 +#undef ABSL_RANDOM_INTERNAL_AES_DISPATCH +#define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1 +#elif defined(__linux__) && defined(ABSL_ARCH_PPC) +// Or when running linux PPC +#undef ABSL_RANDOM_INTERNAL_AES_DISPATCH +#define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1 +#elif defined(__linux__) && defined(ABSL_ARCH_AARCH64) +// Or when running linux AArch64 +#undef ABSL_RANDOM_INTERNAL_AES_DISPATCH +#define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1 +#elif defined(__linux__) && defined(ABSL_ARCH_ARM) && (__ARM_ARCH >= 8) +// Or when running linux ARM v8 or higher. +// (This captures a lot of Android configurations.) +#undef ABSL_RANDOM_INTERNAL_AES_DISPATCH +#define ABSL_RANDOM_INTERNAL_AES_DISPATCH 1 +#endif + +// NaCl does not allow dispatch. +#if defined(__native_client__) +#undef ABSL_RANDOM_INTERNAL_AES_DISPATCH +#define ABSL_RANDOM_INTERNAL_AES_DISPATCH 0 +#endif + +// iOS does not support dispatch, even on x86, since applications +// should be bundled as fat binaries, with a different build tailored for +// each specific supported platform/architecture. +#if defined(__APPLE__) && (TARGET_OS_IPHONE || TARGET_OS_IPHONE_SIMULATOR) +#undef ABSL_RANDOM_INTERNAL_AES_DISPATCH +#define ABSL_RANDOM_INTERNAL_AES_DISPATCH 0 +#endif + +#endif // ABSL_RANDOM_INTERNAL_PLATFORM_H_ |