Fix build for Apple Silicon (pytorch#48)

* Fix build for Apple Silicon

MacOS machines based on Apple M1 silicon are identified by cmake as "arm64"

Modify build rules accordingly to recognize "arm64" is valid CPU configuration for cpuinfo

* Add CPUFAMILY_ARM_FIRESTORM_ICESTORM switch case

* Update comment in src/arm/mach/init.c

CMakeLists.txt

@@ -67,7 +67,7 @@ IF(NOT CMAKE_SYSTEM_PROCESSOR)
       "cpuinfo will compile, but cpuinfo_initialize() will always fail.")
     SET(CPUINFO_SUPPORTED_PLATFORM FALSE)
   ENDIF()
-ELSEIF(NOT CMAKE_SYSTEM_PROCESSOR MATCHES "^(i[3-6]86|AMD64|x86(_64)?|armv[5-8].*|aarch64)$")
+ELSEIF(NOT CMAKE_SYSTEM_PROCESSOR MATCHES "^(i[3-6]86|AMD64|x86(_64)?|armv[5-8].*|aarch64|arm64)$")
   MESSAGE(WARNING
     "Target processor architecture \"${CMAKE_SYSTEM_PROCESSOR}\" is not supported in cpuinfo. "
     "cpuinfo will compile, but cpuinfo_initialize() will always fail.")
@@ -146,7 +146,7 @@ IF(CPUINFO_SUPPORTED_PLATFORM)
     ELSEIF(CMAKE_SYSTEM_NAME MATCHES "^(Windows|CYGWIN|MSYS)$")
       LIST(APPEND CPUINFO_SRCS src/x86/windows/init.c)
     ENDIF()
-  ELSEIF(CMAKE_SYSTEM_PROCESSOR MATCHES "^(armv[5-8].*|aarch64)$" OR IOS_ARCH MATCHES "^(armv7.*|arm64.*)$")
+  ELSEIF(CMAKE_SYSTEM_PROCESSOR MATCHES "^(armv[5-8].*|aarch64|arm64)$" OR IOS_ARCH MATCHES "^(armv7.*|arm64.*)$")
     LIST(APPEND CPUINFO_SRCS
       src/arm/uarch.c
       src/arm/cache.c)
@@ -163,10 +163,10 @@ IF(CPUINFO_SUPPORTED_PLATFORM)
         IF(CMAKE_SYSTEM_NAME STREQUAL "Android" AND ANDROID_ABI STREQUAL "armeabi")
           SET_SOURCE_FILES_PROPERTIES(src/arm/linux/aarch32-isa.c PROPERTIES COMPILE_FLAGS -marm)
         ENDIF()
-      ELSEIF(CMAKE_SYSTEM_PROCESSOR STREQUAL "aarch64")
+      ELSEIF(CMAKE_SYSTEM_PROCESSOR MATCHES "^(aarch64|arm64)$")
         LIST(APPEND CPUINFO_SRCS src/arm/linux/aarch64-isa.c)
       ENDIF()
-    ELSEIF(IOS)
+    ELSEIF(IOS OR (CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND CMAKE_SYSTEM_PROCESSOR STREQUAL "arm64"))
       LIST(APPEND CPUINFO_SRCS src/arm/mach/init.c)
     ENDIF()
     IF(CMAKE_SYSTEM_NAME STREQUAL "Android")

include/cpuinfo.h

@@ -484,6 +484,10 @@ enum cpuinfo_uarch {
 	cpuinfo_uarch_lightning = 0x00700109,
 	/** Apple A13 processor (little cores). */
 	cpuinfo_uarch_thunder   = 0x0070010A,
+	/** Apple M1 processor (big cores). */
+	cpuinfo_uarch_firestorm = 0x0070010B,
+	/** Apple M1 processor (little cores). */
+	cpuinfo_uarch_icestorm  = 0x0070010C,
 
 	/** Cavium ThunderX. */
 	cpuinfo_uarch_thunderx = 0x00800100,

src/arm/mach/init.c

@@ -25,6 +25,10 @@
 	#define CPUFAMILY_ARM_LIGHTNING_THUNDER 0x462504D2
 #endif
 
+#ifndef CPUFAMILY_ARM_FIRESTORM_ICESTORM
+	#define CPUFAMILY_ARM_FIRESTORM_ICESTORM 0x1B588BB3
+#endif
+
 struct cpuinfo_arm_isa cpuinfo_isa = {
 #if CPUINFO_ARCH_ARM
 	.thumb = true,
@@ -101,6 +105,9 @@ static enum cpuinfo_uarch decode_uarch(uint32_t cpu_family, uint32_t cpu_subtype
 		case CPUFAMILY_ARM_LIGHTNING_THUNDER:
 			/* Hexa-core: 2x Lightning + 4x Thunder; Octa-core (presumed): 4x Lightning + 4x Thunder */
 			return core_index + 4 < core_count ? cpuinfo_uarch_lightning : cpuinfo_uarch_thunder;
+		case CPUFAMILY_ARM_FIRESTORM_ICESTORM:
+			/* Hexa-core: 2x Firestorm + 4x Icestorm; Octa-core: 4x Firestorm + 4x Icestorm */
+			return core_index + 4 < core_count ? cpuinfo_uarch_firestorm : cpuinfo_uarch_icestorm;
 		default:
 			/* Use hw.cpusubtype for detection */
 			break;

src/init.c

@@ -37,6 +37,8 @@ bool CPUINFO_ABI cpuinfo_initialize(void) {
 		pthread_once(&init_guard, &cpuinfo_arm_linux_init);
 	#elif defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE
 		pthread_once(&init_guard, &cpuinfo_arm_mach_init);
+	#elif defined(__MACH__) && defined(__APPLE__)
+		pthread_once(&init_guard, &cpuinfo_arm_mach_init);
 	#else
 		cpuinfo_log_error("operating system is not supported in cpuinfo");
 	#endif

tools/cpu-info.c

@@ -233,6 +233,10 @@ static const char* uarch_to_string(enum cpuinfo_uarch uarch) {
 			return "Lightning";
 		case cpuinfo_uarch_thunder:
 			return "Thunder";
+		case cpuinfo_uarch_firestorm:
+			return "Firestorm";
+		case cpuinfo_uarch_icestorm:
+			return "Icestorm";
 		case cpuinfo_uarch_thunderx:
 			return "ThunderX";
 		case cpuinfo_uarch_thunderx2: