Add support for ARM64 darwin (#43)

* Rename linux specific functions and file. * Use sysctlbyname to get ARM64 CRC32 instruction availability. * Tested on ARM64 macOS machine. This might also work on iOS (untested!)
google · Sep 17, 2020 · 1f85030 · 1f85030
1 parent 3bb959c
commit 1f85030
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Showing 6 changed files with 31 additions and 20 deletions.
diff --git a/AUTHORS b/AUTHORS
@@ -8,3 +8,4 @@ Google Inc.
 Fangming Fang <Fangming.Fang@arm.com>
 Vadim Skipin <vadim.skipin@gmail.com>
 Rodrigo Tobar <rtobar@icrar.org>
+Harry Mallon <hjmallon@gmail.com>
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -275,7 +275,7 @@ target_sources(crc32c
   PRIVATE
     "${PROJECT_BINARY_DIR}/include/crc32c/crc32c_config.h"
     "src/crc32c_arm64.h"
-    "src/crc32c_arm64_linux_check.h"
+    "src/crc32c_arm64_check.h"
     "src/crc32c_internal.h"
     "src/crc32c_portable.cc"
     "src/crc32c_prefetch.h"

diff --git a/src/crc32c.cc b/src/crc32c.cc
@@ -8,7 +8,7 @@
 #include <cstdint>
 
 #include "./crc32c_arm64.h"
-#include "./crc32c_arm64_linux_check.h"
+#include "./crc32c_arm64_check.h"
 #include "./crc32c_internal.h"
 #include "./crc32c_sse42.h"
 #include "./crc32c_sse42_check.h"
@@ -20,8 +20,8 @@ uint32_t Extend(uint32_t crc, const uint8_t* data, size_t count) {
   static bool can_use_sse42 = CanUseSse42();
   if (can_use_sse42) return ExtendSse42(crc, data, count);
 #elif HAVE_ARM64_CRC32C
-  static bool can_use_arm_linux = CanUseArm64Linux();
-  if (can_use_arm_linux) return ExtendArm64(crc, data, count);
+  static bool can_use_arm64_crc32 = CanUseArm64Crc32();
+  if (can_use_arm64_crc32) return ExtendArm64(crc, data, count);
 #endif  // HAVE_SSE42 && (defined(_M_X64) || defined(__x86_64__))
 
   return ExtendPortable(crc, data, count);

diff --git a/src/crc32c_arm64.h b/src/crc32c_arm64.h
@@ -2,10 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 
-// Linux-specific code checking the availability for ARM CRC32C instructions.
+// ARM-specific code
 
-#ifndef CRC32C_CRC32C_ARM_LINUX_H_
-#define CRC32C_CRC32C_ARM_LINUX_H_
+#ifndef CRC32C_CRC32C_ARM_H_
+#define CRC32C_CRC32C_ARM_H_
 
 #include <cstddef>
 #include <cstdint>
@@ -22,4 +22,4 @@ uint32_t ExtendArm64(uint32_t crc, const uint8_t* data, size_t count);
 
 #endif  // HAVE_ARM64_CRC32C
 
-#endif  // CRC32C_CRC32C_ARM_LINUX_H_
+#endif  // CRC32C_CRC32C_ARM_H_
diff --git a/src/crc32c_arm64_linux_check.h → src/crc32c_arm64_check.h b/src/crc32c_arm64_linux_check.h → src/crc32c_arm64_check.h
@@ -2,12 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 
-// ARM Linux-specific code checking for the availability of CRC32C instructions.
+// ARM-specific code checking for the availability of CRC32C instructions.
 
-#ifndef CRC32C_CRC32C_ARM_LINUX_CHECK_H_
-#define CRC32C_CRC32C_ARM_LINUX_CHECK_H_
-
-// X86-specific code checking for the availability of SSE4.2 instructions.
+#ifndef CRC32C_CRC32C_ARM_CHECK_H_
+#define CRC32C_CRC32C_ARM_CHECK_H_
 
 #include <cstddef>
 #include <cstdint>
@@ -16,6 +14,7 @@
 
 #if HAVE_ARM64_CRC32C
 
+#ifdef __linux__
 #if HAVE_STRONG_GETAUXVAL
 #include <sys/auxv.h>
 #elif HAVE_WEAK_GETAUXVAL
@@ -25,17 +24,28 @@ extern "C" unsigned long getauxval(unsigned long type) __attribute__((weak));
 
 #define AT_HWCAP 16
 #endif  // HAVE_STRONG_GETAUXVAL || HAVE_WEAK_GETAUXVAL
+#endif  // defined (__linux__)
+
+#ifdef __APPLE__
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#endif  // defined (__APPLE__)
 
 namespace crc32c {
 
-inline bool CanUseArm64Linux() {
-#if HAVE_STRONG_GETAUXVAL || HAVE_WEAK_GETAUXVAL
+inline bool CanUseArm64Crc32() {
+#if defined (__linux__) && (HAVE_STRONG_GETAUXVAL || HAVE_WEAK_GETAUXVAL)
   // From 'arch/arm64/include/uapi/asm/hwcap.h' in Linux kernel source code.
   constexpr unsigned long kHWCAP_PMULL = 1 << 4;
   constexpr unsigned long kHWCAP_CRC32 = 1 << 7;
   unsigned long hwcap = (&getauxval != nullptr) ? getauxval(AT_HWCAP) : 0;
   return (hwcap & (kHWCAP_PMULL | kHWCAP_CRC32)) ==
          (kHWCAP_PMULL | kHWCAP_CRC32);
+#elif defined(__APPLE__)
+  int val = 0;
+  size_t len = sizeof(val);
+  return sysctlbyname("hw.optional.armv8_crc32", &val, &len, nullptr, 0) == 0
+             && val != 0;
 #else
   return false;
 #endif  // HAVE_STRONG_GETAUXVAL || HAVE_WEAK_GETAUXVAL
@@ -45,4 +55,4 @@ inline bool CanUseArm64Linux() {
 
 #endif  // HAVE_ARM64_CRC32C
 
-#endif  // CRC32C_CRC32C_ARM_LINUX_CHECK_H_
+#endif  // CRC32C_CRC32C_ARM_CHECK_H_
diff --git a/src/crc32c_benchmark.cc b/src/crc32c_benchmark.cc
@@ -14,7 +14,7 @@
 #endif  // CRC32C_TESTS_BUILT_WITH_GLOG
 
 #include "./crc32c_arm64.h"
-#include "./crc32c_arm64_linux_check.h"
+#include "./crc32c_arm64_check.h"
 #include "./crc32c_internal.h"
 #include "./crc32c_sse42.h"
 #include "./crc32c_sse42_check.h"
@@ -56,8 +56,8 @@ BENCHMARK_REGISTER_F(CRC32CBenchmark, Portable)
 
 #if HAVE_ARM64_CRC32C
 
-BENCHMARK_DEFINE_F(CRC32CBenchmark, ArmLinux)(benchmark::State& state) {
-  if (!crc32c::CanUseArm64Linux()) {
+BENCHMARK_DEFINE_F(CRC32CBenchmark, ArmCRC32C)(benchmark::State& state) {
+  if (!crc32c::CanUseArm64Crc32()) {
     state.SkipWithError("ARM CRC32C instructions not available or not enabled");
     return;
   }
@@ -67,7 +67,7 @@ BENCHMARK_DEFINE_F(CRC32CBenchmark, ArmLinux)(benchmark::State& state) {
     crc = crc32c::ExtendArm64(crc, block_buffer_, block_size_);
   state.SetBytesProcessed(state.iterations() * block_size_);
 }
-BENCHMARK_REGISTER_F(CRC32CBenchmark, ArmLinux)
+BENCHMARK_REGISTER_F(CRC32CBenchmark, ArmCRC32C)
     ->RangeMultiplier(16)
     ->Range(256, 16777216);  // Block size.