Unable to build this on macOS

[abhi18av]

@gchatelet , I ran into an error while running this command on the macOS system

Abhinavs-MacBook-Pro:cpu_features eklavya$ cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=ON -H. -Bcmake_build
-- The C compiler identification is AppleClang 9.1.0.9020039
-- The CXX compiler identification is AppleClang 9.1.0.9020039
-- Check for working C compiler: /Library/Developer/CommandLineTools/usr/bin/cc
-- Check for working C compiler: /Library/Developer/CommandLineTools/usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /Library/Developer/CommandLineTools/usr/bin/c++
-- Check for working CXX compiler: /Library/Developer/CommandLineTools/usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done
-- Generating done
-- Build files have been written to: /Users/eklavya/projects/code/c-shared-lab/cpu_features/cmake_build


Abhinavs-MacBook-Pro:cpu_features eklavya$ cd cmake_build/


Abhinavs-MacBook-Pro:cmake_build eklavya$ make 
Scanning dependencies of target cpu_features
[  6%] Building C object CMakeFiles/cpu_features.dir/src/linux_features_aggregator.c.o
[ 13%] Building C object CMakeFiles/cpu_features.dir/src/cpuid_x86_clang_gcc.c.o
[ 20%] Building C object CMakeFiles/cpu_features.dir/src/cpuid_x86_msvc.c.o
[ 26%] Building C object CMakeFiles/cpu_features.dir/src/cpuinfo_aarch64.c.o
[ 33%] Building C object CMakeFiles/cpu_features.dir/src/cpuinfo_arm.c.o
[ 40%] Building C object CMakeFiles/cpu_features.dir/src/cpuinfo_mips.c.o
[ 46%] Building C object CMakeFiles/cpu_features.dir/src/cpuinfo_ppc.c.o
[ 53%] Building C object CMakeFiles/cpu_features.dir/src/cpuinfo_x86.c.o
[ 60%] Building C object CMakeFiles/cpu_features.dir/src/filesystem.c.o
[ 66%] Building C object CMakeFiles/cpu_features.dir/src/hwcaps.c.o
[ 73%] Building C object CMakeFiles/cpu_features.dir/src/stack_line_reader.c.o
[ 80%] Building C object CMakeFiles/cpu_features.dir/src/string_view.c.o
[ 86%] Linking C shared library libcpu_features.dylib
Undefined symbols for architecture x86_64:
  "_CpuFeatures_GetPlatformType", referenced from:
      _GetPPCPlatformStrings in cpuinfo_ppc.c.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [libcpu_features.dylib] Error 1
make[1]: *** [CMakeFiles/cpu_features.dir/all] Error 2
make: *** [all] Error 2

[Mizux]

here

cpu_features/include/cpu_features_macros.h

Lines 52 to 62 in 7863534

	#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

I would add

 #if defined(__APPLE__) 
 #define CPU_FEATURES_OS_APPLE 
 #endif 

or

 #if defined(__OSX__) 
 #define CPU_FEATURES_OS_OSX
 #endif 

then adapt accordingly

cpu_features/src/hwcaps.c

Lines 38 to 45 in 7863534

	#if defined(CPU_FEATURES_OS_LINUX_OR_ANDROID) && \
	!defined(HWCAPS_ANDROID_MIPS_OR_ARM)
	#define HWCAPS_REGULAR_LINUX
	#endif
	#if defined(HWCAPS_ANDROID_MIPS_OR_ARM) || defined(HWCAPS_REGULAR_LINUX)
	#define HWCAPS_SUPPORTED
	#endif

[Mizux]

FYI on my macbook pro

%clang -dM -E - </dev/null | grep -i "\(mach\|apple\)"
#define __APPLE_CC__ 6000
#define __APPLE__ 1
#define __MACH__ 1
#define __VERSION__ "4.2.1 Compatible Apple LLVM 9.1.0 (clang-902.0.39.2)"
#define __apple_build_version__ 9020039

[gchatelet]

According to https://sourceforge.net/p/predef/wiki/OperatingSystems/ we should test for __APPLE__ && __MACH__

[Mizux]

Be careful these macros are both defined also on iOS too
src: http://nadeausoftware.com/articles/2012/01/c_c_tip_how_use_compiler_predefined_macros_detect_operating_system#OSXiOSandDarwin

[sl1200mk2]

Hi,
so how to get cpu_features to compile on macOS?
I'm facing the same issue as Mizux...

thank you
++

[Mizux]

@abhi18av @sl1200mk2
It seems you are using the /Library/Developer/CommandLineTools/usr/bin/cc which is the wrong active developer directory.
You should use instead this one /Applications/Xcode-9.4.1.app/Contents/Developer/usr/bin/gcc.

To change please run xcode-select --install

@gchatelet Travis-CI Mac workers seems "correctly" configured in this regard...
see: https://travis-ci.org/google/cpu_features/jobs/427262835#L140-L144

[Mizux]

@gchatelet I still think there is a bug since cpuinfo_ppc.c call CpuFeatures_GetPlatformType();

cpu_features/src/cpuinfo_ppc.c

Lines 167 to 173 in 7863534

	PPCPlatformStrings GetPPCPlatformStrings(void) {
	PPCPlatformStrings strings = kEmptyPPCPlatformStrings;
	FillProcCpuInfoData(&strings);
	strings.type = CpuFeatures_GetPlatformType();
	return strings;
	}

unconditionally declared here:

cpu_features/include/internal/hwcaps.h

Line 127 in 26133d3

PlatformType CpuFeatures_GetPlatformType(void);

But CpuFeatures_GetPlatformType() is undefined for !HWCAPS_SUPPORTED (cf block L177-L187)

cpu_features/src/hwcaps.c

Lines 164 to 187 in 7863534

	PlatformType CpuFeatures_GetPlatformType(void) {
	PlatformType type = kEmptyPlatformType;
	char *platform = (char *)GetHardwareCapabilitiesFor(AT_PLATFORM);
	char *base_platform = (char *)GetHardwareCapabilitiesFor(AT_BASE_PLATFORM);
	if (platform != NULL)
	CpuFeatures_StringView_CopyString(str(platform), type.platform,
	sizeof(type.platform));
	if (base_platform != NULL)
	CpuFeatures_StringView_CopyString(str(base_platform), type.base_platform,
	sizeof(type.base_platform));
	return type;
	}
	#else // (defined(HWCAPS_SUPPORTED)
	////////////////////////////////////////////////////////////////////////////////
	// Implementation of GetHardwareCapabilities for unsupported platforms.
	////////////////////////////////////////////////////////////////////////////////
	const HardwareCapabilities kEmptyHardwareCapabilities;
	HardwareCapabilities CpuFeatures_GetHardwareCapabilities(void) {
	return kEmptyHardwareCapabilities;
	}
	#endif

I think, we should add this to the #else (i.e. L178)

PlatformType kEmptyPlatformType;
PlatformType CpuFeatures_GetPlatformType(void) {
  return kEmptyPlatformType;
}

ps: I think kEmptyPlatformType should be const like kEmptyHardwareCapabilities

cpu_features/src/hwcaps.c

Line 162 in 26133d3

PlatformType kEmptyPlatformType;

cpu_features/src/hwcaps.c

Line 183 in 26133d3

const HardwareCapabilities kEmptyHardwareCapabilities;

[jculpon]

Not @google but I'd like to confirm that a clean CMake on macOS 10.14.2 with a GNU-based toolchain is building successfully, but I have not been able to get tests passing with llvm this morning. This may be unrelated to the issues that @gchatelet / @Mizux are having.

[gchatelet]

@Mizux the build is now fixed. I'm closing the issue.