Config.h not found when building for android x86-64

[DavidVentura]

Hi
I'm trying to build OpenBLAS for Android on x86-64, using CMake, but config.h cannot be included:

common.h:62:10: fatal error: 'config.h' file not found
   62 | #include "config.h"
      |          ^~~~~~~~~~

gen_config_h.c looks suspiciously useful, but I can't figure out which 2 files it wants as parameters -- I'd assumed openblas_config_template.h but no idea for the second one

I tried commenting out the include to see what should come from there, and so far I've only needed to #define ARCH_X86_64, but this feels wrong.

I have not tried building for other targets.

[martin-frbg]

Can you please describe in more detail what you are trying to do - are you cross-compiling on x86_64 to some ARM target running Android, or to an x86_64 device with Android, or are you compiling on the Android device itself ? The config.h file would normally be generated by the getarch helper, or in cross-compilation situations by the script cmake/prebuild.cmake
(using a long list of predefined configurations, which may be missing some cpu targets)

[DavidVentura]

This is an x86_64 linux host, building for an x86_64 android target.

I'm using OpenBLAS as a backend for marian-dev, and including it in my project with

add_subdirectory(third_party/OpenBLAS)

The only value I'm setting is TARGET, to ZEN; I'm not sure why, but the build is considered cross-compilation by cmake

[martin-frbg]

Target ZEN should be supported by prebuild.cmake (you could try the almost-equivalent HASWELL but I doubt it will make a difference). Which compiler, and with Android I assume you are using the ndk ?

[DavidVentura]

Yeah, I'm using the NDK, compiler is the one which comes prebuilt with the NDK: Clang 18. Haswell doesn't make a difference.

I'm 99% sure it's a me problem, but not sure what I can try with this

[martin-frbg]

Maybe the build script from #4952 (comment)
has a few cmake options that you haven't tried ? (Obviously you'd want to use TARGET=ZEN rather than the ATOM in that config, if this is what your Android hardware has)

[martin-frbg]

Did you manage to solve this ? There would have to be something going wrong very early in the build phase of OpenBLAS for config.h tivnot be generated at all, which I think should normally leave a trace in one if the CMake output and/or error files, or in console output