Adding code. Closes #0.

include/cpu_features_macros.h

@@ -0,0 +1,121 @@
+// Copyright 2017 Google Inc.
+//
+// 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
+//
+//    http://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 THIRD_PARTY_CPU_FEATURES_INCLUDE_CPU_FEATURES_MACROS_H_
+#define THIRD_PARTY_CPU_FEATURES_INCLUDE_CPU_FEATURES_MACROS_H_
+
+////////////////////////////////////////////////////////////////////////////////
+// Architectures
+////////////////////////////////////////////////////////////////////////////////
+
+#if ((defined(_M_IX86) || defined(_M_X64) || defined(__i386__) || \
+      defined(__x86_64__)) &&                                     \
+     !defined(__pnacl__) && !defined(__CLR_VER))
+#define CPU_FEATURES_ARCH_X86
+#endif
+
+#if (defined(__arm__) || defined(_M_ARM))
+#define CPU_FEATURES_ARCH_ARM
+#endif
+
+#if defined(__aarch64__)
+#define CPU_FEATURES_ARCH_AARCH64
+#endif
+
+#if (defined(CPU_FEATURES_ARCH_AARCH64) || defined(CPU_FEATURES_ARCH_ARM))
+#define CPU_FEATURES_ARCH_ANY_ARM
+#endif
+
+#if defined(__mips__)
+#define CPU_FEATURES_ARCH_MIPS
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// Os
+////////////////////////////////////////////////////////////////////////////////
+
+#if defined(__linux__)
+#define CPU_FEATURES_OS_LINUX_OR_ANDROID
+#endif
+
+#if defined(__ANDROID__)
+#define CPU_FEATURES_OS_ANDROID
+#endif
+
+#if (defined(_WIN64) || defined(_WIN32))
+#define CPU_FEATURES_OS_WINDOWS
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// Compilers
+////////////////////////////////////////////////////////////////////////////////
+
+#if defined(__clang__)
+#define CPU_FEATURES_COMPILER_CLANG
+#endif
+
+#if defined(__GNUC__) && !defined(__clang__)
+#define CPU_FEATURES_COMPILER_GCC
+#endif
+
+#if defined(_MSC_VER)
+#define CPU_FEATURES_COMPILER_MSC
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// Cpp
+////////////////////////////////////////////////////////////////////////////////
+
+#if defined(__cplusplus)
+#define START_CPP_NAMESPACE \
+  namespace cpu_features {  \
+  extern "C" {
+#define END_CPP_NAMESPACE \
+  }                       \
+  }
+#else
+#define START_CPP_NAMESPACE
+#define END_CPP_NAMESPACE
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// Compiler flags
+////////////////////////////////////////////////////////////////////////////////
+
+// Use the following to check if a feature is known to be available at compile
+// time. See README.md for an example.
+#if defined(CPU_FEATURES_ARCH_X86)
+#define CPU_FEATURES_COMPILED_X86_AES defined(__AES__)
+#define CPU_FEATURES_COMPILED_X86_F16C defined(__F16C__)
+#define CPU_FEATURES_COMPILED_X86_BMI defined(__BMI__)
+#define CPU_FEATURES_COMPILED_X86_BMI2 defined(__BMI2__)
+#define CPU_FEATURES_COMPILED_X86_SSE (defined(__SSE__) || (_M_IX86_FP >= 1))
+#define CPU_FEATURES_COMPILED_X86_SSE2 (defined(__SSE2__) || (_M_IX86_FP >= 2))
+#define CPU_FEATURES_COMPILED_X86_SSE3 defined(__SSE3__)
+#define CPU_FEATURES_COMPILED_X86_SSSE3 defined(__SSSE3__)
+#define CPU_FEATURES_COMPILED_X86_SSE4_1 defined(__SSE4_1__)
+#define CPU_FEATURES_COMPILED_X86_SSE4_2 defined(__SSE4_2__)
+#define CPU_FEATURES_COMPILED_X86_AVX defined(__AVX__)
+#define CPU_FEATURES_COMPILED_x86_AVX2 defined(__AVX2__)
+#endif
+
+#if defined(CPU_FEATURES_ARCH_ANY_ARM)
+#define CPU_FEATURES_COMPILED_ANY_ARM_NEON defined(__ARM_NEON__)
+#endif
+
+#if defined(CPU_FEATURES_ARCH_MIPS)
+#define CPU_FEATURES_COMPILED_MIPS_MSA defined(__mips_msa)
+#endif
+
+#endif  // THIRD_PARTY_CPU_FEATURES_INCLUDE_CPU_FEATURES_MACROS_H_