Add partial implementation of ndk_compat (#54)

* First implementation of ndk_compat
* Restrict building of linux_based_hardware_detection to UNIX
* Fix variable declaration and printf formatting
* Restrict ndk compat to UNIX style systems
* Restrict cpu_mask index to 32
* Fix values display in ndk-compat-test
* Addressing comments

CMakeLists.txt

@@ -16,97 +16,114 @@ option(BUILD_TESTING "Enable test (depends on googletest)." OFF)
 # it prominent in the GUI.
 option(BUILD_SHARED_LIBS "Build library as shared." OFF)
 
-#
-# library : cpu_features
-#
-
 include(CheckIncludeFile)
 include(CheckSymbolExists)
+include(GNUInstallDirs)
 
-check_include_file(dlfcn.h HAVE_DLFCN_H)
+macro(setup_include_and_definitions TARGET_NAME)
-check_symbol_exists(getauxval "sys/auxv.h" HAVE_STRONG_GETAUXVAL)
+  target_include_directories(${TARGET_NAME}
-
+    PUBLIC  $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
-set(_HDRS
+    PRIVATE $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include/internal>
-  include/cpu_features_macros.h
   )
-
+  target_compile_definitions(${TARGET_NAME}
-set(_SRCS
+    PUBLIC STACK_LINE_READER_BUFFER_SIZE=1024
-  include/internal/bit_utils.h
-)
-
-macro(add_linux_detection)
-  if(NOT UNIX)
-    message(FATAL_ERROR "Use of add_linux_detection() on non Linux-like OS")
-  endif()
-  list(APPEND _SRCS
-    include/internal/linux_features_aggregator.h
-    src/linux_features_aggregator.c
-    include/internal/hwcaps.h
-    src/hwcaps.c
-    include/internal/filesystem.h
-    src/filesystem.c
-    include/internal/stack_line_reader.h
-    src/stack_line_reader.c
-    include/internal/string_view.h
-    src/string_view.c
   )
 endmacro()
 
+set(PROCESSOR_IS_MIPS FALSE)
+set(PROCESSOR_IS_ARM FALSE)
+set(PROCESSOR_IS_AARCH64 FALSE)
+set(PROCESSOR_IS_X86 FALSE)
+set(PROCESSOR_IS_POWER FALSE)
+
 if(CMAKE_SYSTEM_PROCESSOR MATCHES "^mips")
-    list(APPEND _HDRS include/cpuinfo_mips.h)
+  set(PROCESSOR_IS_MIPS TRUE)
-    list(APPEND _SRCS src/cpuinfo_mips.c)
-    add_linux_detection()
 elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^arm")
-    list(APPEND _HDRS include/cpuinfo_arm.h)
+  set(PROCESSOR_IS_ARM TRUE)
-    list(APPEND _SRCS src/cpuinfo_arm.c)
-    add_linux_detection()
 elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^aarch64")
-    list(APPEND _HDRS include/cpuinfo_aarch64.h)
+  set(PROCESSOR_IS_AARCH64 TRUE)
-    list(APPEND _SRCS src/cpuinfo_aarch64.c)
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "(x86_64)|(AMD64)|(^i.86$)")
-    add_linux_detection()
+  set(PROCESSOR_IS_X86 TRUE)
-elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64" OR
-       CMAKE_SYSTEM_PROCESSOR STREQUAL "AMD64" OR
-       CMAKE_SYSTEM_PROCESSOR MATCHES "^i.86$")
-    list(APPEND _HDRS include/cpuinfo_x86.h)
-    list(APPEND _HDRS include/internal/cpuid_x86.h)
-    list(APPEND _SRCS src/cpuinfo_x86.c)
-    # add_linux_detection() is not needed on x86, we fetch the features directly
-    # from the CPU.
 elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^(powerpc|ppc)")
-    list(APPEND _HDRS include/cpuinfo_ppc.h)
+  set(PROCESSOR_IS_POWER TRUE)
-    list(APPEND _SRCS src/cpuinfo_ppc.c)
+endif()
-    add_linux_detection()
+
+macro(add_arch_sources HDRS_LIST_NAME SRCS_LIST_NAME)
+  list(APPEND ${HDRS_LIST_NAME} include/cpu_features_macros.h)
+  if(PROCESSOR_IS_MIPS)
+      list(APPEND ${HDRS_LIST_NAME} include/cpuinfo_mips.h)
+      list(APPEND ${SRCS_LIST_NAME} src/cpuinfo_mips.c)
+  elseif(PROCESSOR_IS_ARM)
+      list(APPEND ${HDRS_LIST_NAME} include/cpuinfo_arm.h)
+      list(APPEND ${SRCS_LIST_NAME} src/cpuinfo_arm.c)
+  elseif(PROCESSOR_IS_AARCH64)
+      list(APPEND ${HDRS_LIST_NAME} include/cpuinfo_aarch64.h)
+      list(APPEND ${SRCS_LIST_NAME} src/cpuinfo_aarch64.c)
+  elseif(PROCESSOR_IS_X86)
+      list(APPEND ${HDRS_LIST_NAME} include/cpuinfo_x86.h)
+      list(APPEND ${HDRS_LIST_NAME} include/internal/cpuid_x86.h)
+      list(APPEND ${SRCS_LIST_NAME} src/cpuinfo_x86.c)
+  elseif(PROCESSOR_IS_POWER)
+      list(APPEND ${HDRS_LIST_NAME} include/cpuinfo_ppc.h)
+      list(APPEND ${SRCS_LIST_NAME} src/cpuinfo_ppc.c)
   else()
     message(FATAL_ERROR "Unsupported architectures ${CMAKE_SYSTEM_PROCESSOR}")
   endif()
+endmacro()
 
-add_library(cpu_features ${_HDRS} ${_SRCS})
+#
+# library : utils
+#
 
-target_include_directories(cpu_features
+add_library(utils OBJECT
-  PUBLIC
+  include/internal/bit_utils.h
-  $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
+  include/internal/filesystem.h
-  $<INSTALL_INTERFACE:include/cpu_features>
+  include/internal/stack_line_reader.h
-  PRIVATE
+  include/internal/string_view.h
-  include/internal
+  src/filesystem.c
+  src/stack_line_reader.c
+  src/string_view.c
 )
-set_target_properties(cpu_features PROPERTIES PUBLIC_HEADER "${_HDRS}")
+setup_include_and_definitions(utils)
-target_compile_definitions(cpu_features PUBLIC STACK_LINE_READER_BUFFER_SIZE=1024)
+
+#
+# library : unix_based_hardware_detection
+#
+
+if(UNIX)
+  add_library(unix_based_hardware_detection OBJECT
+    include/internal/hwcaps.h
+    include/internal/unix_features_aggregator.h
+    src/hwcaps.c
+    src/unix_features_aggregator.c
+  )
+  setup_include_and_definitions(unix_based_hardware_detection)
+  check_include_file(dlfcn.h HAVE_DLFCN_H)
   if(HAVE_DLFCN_H)
-  target_compile_definitions(cpu_features PRIVATE HAVE_DLFCN_H)
+    target_compile_definitions(unix_based_hardware_detection PRIVATE HAVE_DLFCN_H)
   endif()
+  check_symbol_exists(getauxval "sys/auxv.h" HAVE_STRONG_GETAUXVAL)
   if(HAVE_STRONG_GETAUXVAL)
-  target_compile_definitions(cpu_features PRIVATE HAVE_STRONG_GETAUXVAL)
+    target_compile_definitions(unix_based_hardware_detection PRIVATE HAVE_STRONG_GETAUXVAL)
   endif()
+endif()
+
+#
+# library : cpu_features
+#
+set (CPU_FEATURES_HDRS)
+set (CPU_FEATURES_SRCS)
+add_arch_sources(CPU_FEATURES_HDRS CPU_FEATURES_SRCS)
+list(APPEND CPU_FEATURES_SRCS $<TARGET_OBJECTS:utils>)
+if(NOT PROCESSOR_IS_X86 AND UNIX)
+  list(APPEND CPU_FEATURES_SRCS $<TARGET_OBJECTS:unix_based_hardware_detection>)
+endif()
+add_library(cpu_features ${CPU_FEATURES_HDRS} ${CPU_FEATURES_SRCS})
+setup_include_and_definitions(cpu_features)
 target_link_libraries(cpu_features PUBLIC ${CMAKE_DL_LIBS})
-
+target_include_directories(cpu_features
-# The use of shared libraries is discouraged.
+  PUBLIC $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/cpu_features>
-# For API / ABI compatibility reasons, it is recommended to build and use
+)
-# cpu_features in a subdirectory of your project or as an embedded dependency.
-if(BUILD_SHARED_LIBS)
-  set_property(TARGET cpu_features PROPERTY POSITION_INDEPENDENT_CODE ON)
-endif()
-add_library(CpuFeature::cpu_features ALIAS cpu_features)
-
 #
 # program : list_cpu_features
 #
@@ -115,6 +132,31 @@ add_executable(list_cpu_features src/utils/list_cpu_features.c)
 target_link_libraries(list_cpu_features PRIVATE cpu_features)
 add_executable(CpuFeature::list_cpu_features ALIAS list_cpu_features)
 
+#
+# library : NDK compat
+#
+if(ANDROID)
+  find_package(Threads)
+  set (NDK_COMPAT_HDRS ndk_compat/cpu-features.h)
+  set (NDK_COMPAT_SRCS
+    ndk_compat/cpu-features.c
+    $<TARGET_OBJECTS:utils>
+    $<TARGET_OBJECTS:unix_based_hardware_detection>
+  )
+  add_arch_sources(NDK_COMPAT_HDRS NDK_COMPAT_SRCS)
+  add_library(ndk_compat ${NDK_COMPAT_HDRS} ${NDK_COMPAT_SRCS})
+  setup_include_and_definitions(ndk_compat)
+  target_link_libraries(ndk_compat PUBLIC ${CMAKE_DL_LIBS} ${CMAKE_THREAD_LIBS_INIT})
+endif()
+
+#
+# program : NDK compat test program
+#
+if(ANDROID AND ENABLE_TESTING)
+  add_executable(ndk-compat-test ndk_compat/ndk-compat-test.c)
+  target_link_libraries(ndk-compat-test PRIVATE ndk_compat)
+endif()
+
 #
 # tests
 #

ndk_compat/README.md

@@ -0,0 +1,4 @@
+Provides a header compatible with [android's NDK cpu-features.h](https://android.googlesource.com/platform/ndk/+/master/sources/android/cpufeatures/cpu-features.h).
+
+It is intended to be a drop in replacement for this header and help users
+transition from the NDK to [Google's cpu_features library](https://github.com/google/cpu_features).

ndk_compat/cpu-features.c

@@ -0,0 +1,199 @@
+#include "cpu-features.h"
+#include "cpu_features_macros.h"
+#include "internal/filesystem.h"
+#include "internal/stack_line_reader.h"
+#include "internal/string_view.h"
+
+#include <pthread.h>
+
+#if defined(CPU_FEATURES_ARCH_ARM)
+#include "cpuinfo_arm.h"
+#elif defined(CPU_FEATURES_ARCH_X86)
+#include "cpuinfo_x86.h"
+#elif defined(CPU_FEATURES_ARCH_MIPS)
+#include "cpuinfo_mips.h"
+#elif defined(CPU_FEATURES_ARCH_AARCH64)
+#include "cpuinfo_aarch64.h"
+#endif
+
+static pthread_once_t g_once;
+static int g_inited;
+static uint64_t g_cpuFeatures;
+static int g_cpuCount;
+
+#ifdef CPU_FEATURES_ARCH_ARM
+static uint32_t g_cpuIdArm;
+#endif
+
+static void set_cpu_mask_bit(uint32_t index, uint32_t* cpu_mask) {
+  *cpu_mask |= 1UL << index;
+}
+
+// Examples of valid inputs: "31", "4-31"
+static void parse_cpu_mask(const StringView text, uint32_t* cpu_mask) {
+  int separator_index = CpuFeatures_StringView_IndexOfChar(text, '-');
+  if (separator_index < 0) {  // A single cpu index
+    int cpu_index = CpuFeatures_StringView_ParsePositiveNumber(text);
+    if (cpu_index < 0) return;
+    set_cpu_mask_bit(cpu_index, cpu_mask);
+  } else {
+    int cpu_index_a = CpuFeatures_StringView_ParsePositiveNumber(
+        CpuFeatures_StringView_KeepFront(text, separator_index));
+    int cpu_index_b = CpuFeatures_StringView_ParsePositiveNumber(
+        CpuFeatures_StringView_PopFront(text, separator_index + 1));
+    int i;
+    if (cpu_index_a < 0 || cpu_index_b < 0) return;
+    for (i = cpu_index_a; i <= cpu_index_b; ++i) {
+      if (i < 32) {
+        set_cpu_mask_bit(i, cpu_mask);
+      }
+    }
+  }
+}
+
+// Format specification from
+// https://www.kernel.org/doc/Documentation/cputopology.txt
+// Examples of valid inputs: "31", "2,4-31,32-63", "0-1,3"
+static void parse_cpu_mask_line(const LineResult result, uint32_t* cpu_mask) {
+  if (!result.full_line || result.eof) return;
+  StringView line = result.line;
+  for (; line.size > 0;) {
+    int next_entry_index = CpuFeatures_StringView_IndexOfChar(line, ',');
+    if (next_entry_index < 0) {
+      parse_cpu_mask(line, cpu_mask);
+      break;
+    }
+    StringView entry = CpuFeatures_StringView_KeepFront(line, next_entry_index);
+    parse_cpu_mask(entry, cpu_mask);
+    line = CpuFeatures_StringView_PopFront(line, next_entry_index + 1);
+  }
+}
+
+static void update_cpu_mask_from_file(const char* filename,
+                                      uint32_t* cpu_mask) {
+  const int fd = CpuFeatures_OpenFile(filename);
+  if (fd >= 0) {
+    StackLineReader reader;
+    StackLineReader_Initialize(&reader, fd);
+    parse_cpu_mask_line(StackLineReader_NextLine(&reader), cpu_mask);
+    CpuFeatures_CloseFile(fd);
+  }
+}
+
+static int get_cpu_count(void) {
+  uint32_t cpu_mask = 0;
+  update_cpu_mask_from_file("/sys/devices/system/cpu/present", &cpu_mask);
+  update_cpu_mask_from_file("/sys/devices/system/cpu/possible", &cpu_mask);
+  return __builtin_popcount(cpu_mask);
+}
+
+static void android_cpuInit(void) {
+  g_cpuFeatures = 0;
+  g_cpuCount = 1;
+  g_inited = 1;
+
+  g_cpuCount = get_cpu_count();
+  if (g_cpuCount == 0) {
+    g_cpuCount = 1;
+  }
+#if defined(CPU_FEATURES_ARCH_ARM)
+  ArmInfo info = GetArmInfo();
+  if (info.architecture == 7) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_ARMv7;
+  if (info.features.vfpv3) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
+  if (info.features.neon) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_NEON;
+  if (info.features.vfpv3d16) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFP_FP16;
+  if (info.features.idiva) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_ARM;
+  if (info.features.idivt) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_THUMB2;
+  if (info.features.iwmmxt) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_iWMMXt;
+  if (info.features.aes) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_AES;
+  if (info.features.pmull) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_PMULL;
+  if (info.features.sha1) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_SHA1;
+  if (info.features.sha2) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_SHA2;
+  if (info.features.crc32) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_CRC32;
+  // if (info.features.) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_LDREX_STREX;
+  // if (info.features.) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv2;
+  // if (info.features.) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFP_D32;
+  // if (info.features.) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFP_FMA;
+  // if (info.features.) g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_NEON_FMA;
+  g_cpuIdArm = GetArmCpuId(&info);
+#elif defined(CPU_FEATURES_ARCH_X86)
+  X86Info info = GetX86Info();
+  if (info.features.ssse3) g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_SSSE3;
+  if (info.features.sse4_1) g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_SSE4_1;
+  if (info.features.sse4_2) g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_SSE4_2;
+  if (info.features.avx) g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_AVX;
+  if (info.features.avx2) g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_AVX2;
+    // if (info.features.) g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_MOVBE;
+    // if (info.features.) g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_AES_NI;
+    // if (info.features.) g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_RDRAND;
+    // if (info.features.) g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_POPCNT;
+    // if (info.features.) g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_SHA_NI;
+#elif defined(CPU_FEATURES_ARCH_MIPS)
+  MipsInfo info = GetMipsInfo();
+  // if (info.features.) g_cpuFeatures |= ANDROID_CPU_MIPS_FEATURE_R6;
+  if (info.features.msa) g_cpuFeatures |= ANDROID_CPU_MIPS_FEATURE_MSA;
+#elif defined(CPU_FEATURES_ARCH_AARCH64)
+  Aarch64Info info = GetAarch64Info();
+  if (info.features.fp) g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_FP;
+  if (info.features.asimd) g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_ASIMD;
+  if (info.features.aes) g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_AES;
+  if (info.features.pmull) g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_PMULL;
+  if (info.features.sha1) g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_SHA1;
+  if (info.features.sha2) g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_SHA2;
+  if (info.features.crc32) g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_CRC32;
+#endif
+}
+
+AndroidCpuFamily android_getCpuFamily(void) {
+#if defined(CPU_FEATURES_ARCH_ARM)
+  return ANDROID_CPU_FAMILY_ARM;
+#elif defined(CPU_FEATURES_ARCH_X86_32)
+  return ANDROID_CPU_FAMILY_X86;
+#elif defined(CPU_FEATURES_ARCH_MIPS64)
+  return ANDROID_CPU_FAMILY_MIPS64;
+#elif defined(CPU_FEATURES_ARCH_MIPS32)
+  return ANDROID_CPU_FAMILY_MIPS;
+#elif defined(CPU_FEATURES_ARCH_AARCH64)
+  return ANDROID_CPU_FAMILY_ARM64;
+#elif defined(CPU_FEATURES_ARCH_X86_64)
+  return ANDROID_CPU_FAMILY_X86_64;
+#else
+  return ANDROID_CPU_FAMILY_UNKNOWN;
+#endif
+}
+
+uint64_t android_getCpuFeatures(void) {
+  pthread_once(&g_once, android_cpuInit);
+  return g_cpuFeatures;
+}
+
+int android_getCpuCount(void) {
+  pthread_once(&g_once, android_cpuInit);
+  return g_cpuCount;
+}
+
+static void android_cpuInitDummy(void) { g_inited = 1; }
+
+int android_setCpu(int cpu_count, uint64_t cpu_features) {
+  /* Fail if the library was already initialized. */
+  if (g_inited) return 0;
+  g_cpuCount = (cpu_count <= 0 ? 1 : cpu_count);
+  g_cpuFeatures = cpu_features;
+  pthread_once(&g_once, android_cpuInitDummy);
+  return 1;
+}
+
+#ifdef CPU_FEATURES_ARCH_ARM
+
+uint32_t android_getCpuIdArm(void) {
+  pthread_once(&g_once, android_cpuInit);
+  return g_cpuIdArm;
+}
+
+int android_setCpuArm(int cpu_count, uint64_t cpu_features, uint32_t cpu_id) {
+  if (!android_setCpu(cpu_count, cpu_features)) return 0;
+  g_cpuIdArm = cpu_id;
+  return 1;
+}
+
+#endif  // CPU_FEATURES_ARCH_ARM

ndk_compat/cpu-features.h

@@ -0,0 +1,318 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#ifndef GOOGLE_CPU_FEATURES_H
+#define GOOGLE_CPU_FEATURES_H
+#include <stdint.h>
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+
+/* A list of valid values returned by android_getCpuFamily().
+ * They describe the CPU Architecture of the current process.
+ */
+typedef enum {
+  ANDROID_CPU_FAMILY_UNKNOWN = 0,
+  ANDROID_CPU_FAMILY_ARM,
+  ANDROID_CPU_FAMILY_X86,
+  ANDROID_CPU_FAMILY_MIPS,
+  ANDROID_CPU_FAMILY_ARM64,
+  ANDROID_CPU_FAMILY_X86_64,
+  ANDROID_CPU_FAMILY_MIPS64,
+  ANDROID_CPU_FAMILY_MAX /* do not remove */
+} AndroidCpuFamily;
+
+/* Return the CPU family of the current process.
+ *
+ * Note that this matches the bitness of the current process. I.e. when
+ * running a 32-bit binary on a 64-bit capable CPU, this will return the
+ * 32-bit CPU family value.
+ */
+extern AndroidCpuFamily android_getCpuFamily(void);
+
+/* Return a bitmap describing a set of optional CPU features that are
+ * supported by the current device's CPU. The exact bit-flags returned
+ * depend on the value returned by android_getCpuFamily(). See the
+ * documentation for the ANDROID_CPU_*_FEATURE_* flags below for details.
+ */
+extern uint64_t android_getCpuFeatures(void);
+
+/* The list of feature flags for ANDROID_CPU_FAMILY_ARM that can be
+ * recognized by the library (see note below for 64-bit ARM). Value details
+ * are:
+ *
+ *   VFPv2:
+ *     CPU supports the VFPv2 instruction set. Many, but not all, ARMv6 CPUs
+ *     support these instructions. VFPv2 is a subset of VFPv3 so this will
+ *     be set whenever VFPv3 is set too.
+ *
+ *   ARMv7:
+ *     CPU supports the ARMv7-A basic instruction set.
+ *     This feature is mandated by the 'armeabi-v7a' ABI.
+ *
+ *   VFPv3:
+ *     CPU supports the VFPv3-D16 instruction set, providing hardware FPU
+ *     support for single and double precision floating point registers.
+ *     Note that only 16 FPU registers are available by default, unless
+ *     the D32 bit is set too. This feature is also mandated by the
+ *     'armeabi-v7a' ABI.
+ *
+ *   VFP_D32:
+ *     CPU VFP optional extension that provides 32 FPU registers,
+ *     instead of 16. Note that ARM mandates this feature is the 'NEON'
+ *     feature is implemented by the CPU.
+ *
+ *   NEON:
+ *     CPU FPU supports "ARM Advanced SIMD" instructions, also known as
+ *     NEON. Note that this mandates the VFP_D32 feature as well, per the
+ *     ARM Architecture specification.
+ *
+ *   VFP_FP16:
+ *     Half-width floating precision VFP extension. If set, the CPU
+ *     supports instructions to perform floating-point operations on
+ *     16-bit registers. This is part of the VFPv4 specification, but
+ *     not mandated by any Android ABI.
+ *
+ *   VFP_FMA:
+ *     Fused multiply-accumulate VFP instructions extension. Also part of
+ *     the VFPv4 specification, but not mandated by any Android ABI.
+ *
+ *   NEON_FMA:
+ *     Fused multiply-accumulate NEON instructions extension. Optional
+ *     extension from the VFPv4 specification, but not mandated by any
+ *     Android ABI.
+ *
+ *   IDIV_ARM:
+ *     Integer division available in ARM mode. Only available
+ *     on recent CPUs (e.g. Cortex-A15).
+ *
+ *   IDIV_THUMB2:
+ *     Integer division available in Thumb-2 mode. Only available
+ *     on recent CPUs (e.g. Cortex-A15).
+ *
+ *   iWMMXt:
+ *     Optional extension that adds MMX registers and operations to an
+ *     ARM CPU. This is only available on a few XScale-based CPU designs
+ *     sold by Marvell. Pretty rare in practice.
+ *
+ *   AES:
+ *     CPU supports AES instructions. These instructions are only
+ *     available for 32-bit applications running on ARMv8 CPU.
+ *
+ *   CRC32:
+ *     CPU supports CRC32 instructions. These instructions are only
+ *     available for 32-bit applications running on ARMv8 CPU.
+ *
+ *   SHA2:
+ *     CPU supports SHA2 instructions. These instructions are only
+ *     available for 32-bit applications running on ARMv8 CPU.
+ *
+ *   SHA1:
+ *     CPU supports SHA1 instructions. These instructions are only
+ *     available for 32-bit applications running on ARMv8 CPU.
+ *
+ *   PMULL:
+ *     CPU supports 64-bit PMULL and PMULL2 instructions. These
+ *     instructions are only available for 32-bit applications
+ *     running on ARMv8 CPU.
+ *
+ * If you want to tell the compiler to generate code that targets one of
+ * the feature set above, you should probably use one of the following
+ * flags (for more details, see technical note at the end of this file):
+ *
+ *   -mfpu=vfp
+ *   -mfpu=vfpv2
+ *     These are equivalent and tell GCC to use VFPv2 instructions for
+ *     floating-point operations. Use this if you want your code to
+ *     run on *some* ARMv6 devices, and any ARMv7-A device supported
+ *     by Android.
+ *
+ *     Generated code requires VFPv2 feature.
+ *
+ *   -mfpu=vfpv3-d16
+ *     Tell GCC to use VFPv3 instructions (using only 16 FPU registers).
+ *     This should be generic code that runs on any CPU that supports the
+ *     'armeabi-v7a' Android ABI. Note that no ARMv6 CPU supports this.
+ *
+ *     Generated code requires VFPv3 feature.
+ *
+ *   -mfpu=vfpv3
+ *     Tell GCC to use VFPv3 instructions with 32 FPU registers.
+ *     Generated code requires VFPv3|VFP_D32 features.
+ *
+ *   -mfpu=neon
+ *     Tell GCC to use VFPv3 instructions with 32 FPU registers, and
+ *     also support NEON intrinsics (see <arm_neon.h>).
+ *     Generated code requires VFPv3|VFP_D32|NEON features.
+ *
+ *   -mfpu=vfpv4-d16
+ *     Generated code requires VFPv3|VFP_FP16|VFP_FMA features.
+ *
+ *   -mfpu=vfpv4
+ *     Generated code requires VFPv3|VFP_FP16|VFP_FMA|VFP_D32 features.
+ *
+ *   -mfpu=neon-vfpv4
+ *     Generated code requires VFPv3|VFP_FP16|VFP_FMA|VFP_D32|NEON|NEON_FMA
+ *     features.
+ *
+ *   -mcpu=cortex-a7
+ *   -mcpu=cortex-a15
+ *     Generated code requires VFPv3|VFP_FP16|VFP_FMA|VFP_D32|
+ *                             NEON|NEON_FMA|IDIV_ARM|IDIV_THUMB2
+ *     This flag implies -mfpu=neon-vfpv4.
+ *
+ *   -mcpu=iwmmxt
+ *     Allows the use of iWMMXt instrinsics with GCC.
+ *
+ * IMPORTANT NOTE: These flags should only be tested when
+ * android_getCpuFamily() returns ANDROID_CPU_FAMILY_ARM, i.e. this is a
+ * 32-bit process.
+ *
+ * When running a 64-bit ARM process on an ARMv8 CPU,
+ * android_getCpuFeatures() will return a different set of bitflags
+ */
+enum {
+  ANDROID_CPU_ARM_FEATURE_ARMv7 = (1 << 0),
+  ANDROID_CPU_ARM_FEATURE_VFPv3 = (1 << 1),
+  ANDROID_CPU_ARM_FEATURE_NEON = (1 << 2),
+  ANDROID_CPU_ARM_FEATURE_LDREX_STREX = (1 << 3),
+  ANDROID_CPU_ARM_FEATURE_VFPv2 = (1 << 4),
+  ANDROID_CPU_ARM_FEATURE_VFP_D32 = (1 << 5),
+  ANDROID_CPU_ARM_FEATURE_VFP_FP16 = (1 << 6),
+  ANDROID_CPU_ARM_FEATURE_VFP_FMA = (1 << 7),
+  ANDROID_CPU_ARM_FEATURE_NEON_FMA = (1 << 8),
+  ANDROID_CPU_ARM_FEATURE_IDIV_ARM = (1 << 9),
+  ANDROID_CPU_ARM_FEATURE_IDIV_THUMB2 = (1 << 10),
+  ANDROID_CPU_ARM_FEATURE_iWMMXt = (1 << 11),
+  ANDROID_CPU_ARM_FEATURE_AES = (1 << 12),
+  ANDROID_CPU_ARM_FEATURE_PMULL = (1 << 13),
+  ANDROID_CPU_ARM_FEATURE_SHA1 = (1 << 14),
+  ANDROID_CPU_ARM_FEATURE_SHA2 = (1 << 15),
+  ANDROID_CPU_ARM_FEATURE_CRC32 = (1 << 16),
+};
+
+/* The bit flags corresponding to the output of android_getCpuFeatures()
+ * when android_getCpuFamily() returns ANDROID_CPU_FAMILY_ARM64. Value details
+ * are:
+ *
+ *   FP:
+ *     CPU has Floating-point unit.
+ *
+ *   ASIMD:
+ *     CPU has Advanced SIMD unit.
+ *
+ *   AES:
+ *     CPU supports AES instructions.
+ *
+ *   CRC32:
+ *     CPU supports CRC32 instructions.
+ *
+ *   SHA2:
+ *     CPU supports SHA2 instructions.
+ *
+ *   SHA1:
+ *     CPU supports SHA1 instructions.
+ *
+ *   PMULL:
+ *     CPU supports 64-bit PMULL and PMULL2 instructions.
+ */
+enum {
+  ANDROID_CPU_ARM64_FEATURE_FP = (1 << 0),
+  ANDROID_CPU_ARM64_FEATURE_ASIMD = (1 << 1),
+  ANDROID_CPU_ARM64_FEATURE_AES = (1 << 2),
+  ANDROID_CPU_ARM64_FEATURE_PMULL = (1 << 3),
+  ANDROID_CPU_ARM64_FEATURE_SHA1 = (1 << 4),
+  ANDROID_CPU_ARM64_FEATURE_SHA2 = (1 << 5),
+  ANDROID_CPU_ARM64_FEATURE_CRC32 = (1 << 6),
+};
+
+/* The bit flags corresponding to the output of android_getCpuFeatures()
+ * when android_getCpuFamily() returns ANDROID_CPU_FAMILY_X86 or
+ * ANDROID_CPU_FAMILY_X86_64.
+ */
+enum {
+  ANDROID_CPU_X86_FEATURE_SSSE3 = (1 << 0),
+  ANDROID_CPU_X86_FEATURE_POPCNT = (1 << 1),
+  ANDROID_CPU_X86_FEATURE_MOVBE = (1 << 2),
+  ANDROID_CPU_X86_FEATURE_SSE4_1 = (1 << 3),
+  ANDROID_CPU_X86_FEATURE_SSE4_2 = (1 << 4),
+  ANDROID_CPU_X86_FEATURE_AES_NI = (1 << 5),
+  ANDROID_CPU_X86_FEATURE_AVX = (1 << 6),
+  ANDROID_CPU_X86_FEATURE_RDRAND = (1 << 7),
+  ANDROID_CPU_X86_FEATURE_AVX2 = (1 << 8),
+  ANDROID_CPU_X86_FEATURE_SHA_NI = (1 << 9),
+};
+
+/* The bit flags corresponding to the output of android_getCpuFeatures()
+ * when android_getCpuFamily() returns ANDROID_CPU_FAMILY_MIPS
+ * or ANDROID_CPU_FAMILY_MIPS64.  Values are:
+ *
+ *   R6:
+ *     CPU executes MIPS Release 6 instructions natively, and
+ *     supports obsoleted R1..R5 instructions only via kernel traps.
+ *
+ *   MSA:
+ *     CPU supports Mips SIMD Architecture instructions.
+ */
+enum {
+  ANDROID_CPU_MIPS_FEATURE_R6 = (1 << 0),
+  ANDROID_CPU_MIPS_FEATURE_MSA = (1 << 1),
+};
+
+/* Return the number of CPU cores detected on this device. */
+extern int android_getCpuCount(void);
+
+/* The following is used to force the CPU count and features
+ * mask in sandboxed processes. Under 4.1 and higher, these processes
+ * cannot access /proc, which is the only way to get information from
+ * the kernel about the current hardware (at least on ARM).
+ *
+ * It _must_ be called only once, and before any android_getCpuXXX
+ * function, any other case will fail.
+ *
+ * This function return 1 on success, and 0 on failure.
+ */
+extern int android_setCpu(int cpu_count, uint64_t cpu_features);
+
+#ifdef __arm__
+
+/* Retrieve the ARM 32-bit CPUID value from the kernel.
+ * Note that this cannot work on sandboxed processes under 4.1 and
+ * higher, unless you called android_setCpuArm() before.
+ */
+extern uint32_t android_getCpuIdArm(void);
+
+/* An ARM-specific variant of android_setCpu() that also allows you
+ * to set the ARM CPUID field.
+ */
+extern int android_setCpuArm(int cpu_count, uint64_t cpu_features,
+                             uint32_t cpu_id);
+
+#endif
+
+__END_DECLS
+#endif /* GOOGLE_CPU_FEATURES_H */

ndk_compat/ndk-compat-test.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+#include "cpu-features.h"
+
+int main() {
+  printf("android_getCpuFamily()=%d\n", android_getCpuFamily());
+  printf("android_getCpuFeatures()=0x%08llx\n", android_getCpuFeatures());
+  printf("android_getCpuCount()=%d\n", android_getCpuCount());
+#ifdef __arm__
+  printf("android_getCpuIdArm()=0x%04x\n", android_getCpuIdArm());
+#endif  //__arm__
+}

src/cpuinfo_aarch64.c

@@ -16,9 +16,9 @@
 
 #include "internal/filesystem.h"
 #include "internal/hwcaps.h"
-#include "internal/linux_features_aggregator.h"
 #include "internal/stack_line_reader.h"
 #include "internal/string_view.h"
+#include "internal/unix_features_aggregator.h"
 
 #include <ctype.h>
 

src/cpuinfo_arm.c

@@ -17,9 +17,9 @@
 #include "internal/bit_utils.h"
 #include "internal/filesystem.h"
 #include "internal/hwcaps.h"
-#include "internal/linux_features_aggregator.h"
 #include "internal/stack_line_reader.h"
 #include "internal/string_view.h"
+#include "internal/unix_features_aggregator.h"
 
 #include <ctype.h>
 

src/cpuinfo_mips.c

@@ -15,9 +15,9 @@
 #include "cpuinfo_mips.h"
 
 #include "internal/filesystem.h"
-#include "internal/linux_features_aggregator.h"
 #include "internal/stack_line_reader.h"
 #include "internal/string_view.h"
+#include "internal/unix_features_aggregator.h"
 
 DECLARE_SETTER(MipsFeatures, msa)
 DECLARE_SETTER(MipsFeatures, eva)

src/cpuinfo_ppc.c

@@ -18,9 +18,9 @@
 #include "cpuinfo_ppc.h"
 #include "internal/bit_utils.h"
 #include "internal/filesystem.h"
-#include "internal/linux_features_aggregator.h"
 #include "internal/stack_line_reader.h"
 #include "internal/string_view.h"
+#include "internal/unix_features_aggregator.h"
 
 DECLARE_SETTER(PPCFeatures, ppc32)
 DECLARE_SETTER(PPCFeatures, ppc64)

src/unix_features_aggregator.c

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include "internal/linux_features_aggregator.h"
+#include "internal/unix_features_aggregator.h"
 #include "internal/string_view.h"
 
 void CpuFeatures_SetFromFlags(const size_t configs_size,

test/CMakeLists.txt

@@ -27,7 +27,7 @@ add_library(stack_line_reader_for_test ../src/stack_line_reader.c)
 target_compile_definitions(stack_line_reader_for_test PUBLIC STACK_LINE_READER_BUFFER_SIZE=16)
 target_link_libraries(stack_line_reader_for_test string_view filesystem_for_testing)
 ##------------------------------------------------------------------------------
-add_library(all_libraries ../src/stack_line_reader.c ../src/linux_features_aggregator.c)
+add_library(all_libraries ../src/stack_line_reader.c ../src/unix_features_aggregator.c)
 target_link_libraries(all_libraries hwcaps_for_testing stack_line_reader string_view)
 
 #
@@ -50,10 +50,10 @@ add_executable(stack_line_reader_test stack_line_reader_test.cc)
 target_link_libraries(stack_line_reader_test stack_line_reader_for_test)
 add_test(NAME stack_line_reader_test COMMAND stack_line_reader_test)
 ##------------------------------------------------------------------------------
-## linux_features_aggregator_test
+## unix_features_aggregator_test
-add_executable(linux_features_aggregator_test linux_features_aggregator_test.cc)
+add_executable(unix_features_aggregator_test unix_features_aggregator_test.cc)
-target_link_libraries(linux_features_aggregator_test all_libraries)
+target_link_libraries(unix_features_aggregator_test all_libraries)
-add_test(NAME linux_features_aggregator_test COMMAND linux_features_aggregator_test)
+add_test(NAME unix_features_aggregator_test COMMAND unix_features_aggregator_test)
 ##------------------------------------------------------------------------------
 ## cpuinfo_x86_test
 if(CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")

test/unix_features_aggregator_test.cc

@@ -14,7 +14,7 @@
 
 #include <array>
 
-#include "internal/linux_features_aggregator.h"
+#include "internal/unix_features_aggregator.h"
 
 #include "gtest/gtest.h"