what is the libgcc_s requirement in LAPACK?

[jhgorse]

Greetings,

I was trying to compile a 3rd party app for the new Apple M1 cpu and found some difficulty linking due to LAPACK's libgcc requirement. Specifically, ld: file not found: @rpath/libgcc_s.1.1.dylib for architecture arm64

The 3rd party build was done with clang.

The libgcc dep appeared to come from OpenBLAS/LAPACK's use of gfortran.

Is there any chance that libgcc might be mistakenly getting included in the LAPACK build?

Cheers,
Joe

[weslleyspereira]

Hi!
I have some questions to try to help you:

• Are you trying to build LAPACK with Makefile or CMake? The C Compiler is set to gcc in some make.inc files.
• Have you tried compiling LAPACK with the reference BLAS instead of OpenBLAS?

[martin-frbg]

I'm fairly certain that you will get the depencency on libgcc_s (gcc's runtime library) even just from compiling the LAPACK Fortran source with gfortran, with no C code in the mix. The alternative would be to compile everything with flang (not entirely sure if this is considered stable on the M1 yet), nvfortran or the commercial NAG fortran compiler.

[jhgorse]

@weslleyspereira, I have built it both ways. The make.inc.default from gcc to cc just worked. I had to run the */ Makefiles to generate the _mangling.h headers, but it otherwise worked without a hitch.

I do not see any references to the libgcc_s library, though I did not xref through all of it's symbols. If it grabbed any of the long int type numeric symbols, it does so without further issue because it is a statically linked set of .a libraries.

@martin-frbg, I did try to build flang and failed. Did not look too deep into it. I didn't know about nvfortran! Looks neat! =)

Cheers,
Joe

[weslleyspereira]

@weslleyspereira, I have built it both ways. The make.inc.default from gcc to cc just worked. I had to run the */ Makefiles to generate the _mangling.h headers, but it otherwise worked without a hitch.

Good! We have been trying to improve the installation of the mangling files, see #584 and #616. Currently, one must run CBLAS/ and LAPACKE/ Makefiles to get the _mangling files installed.

[weslleyspereira]

We just merged a PR which improves the installation of mangling files for lapack.h. Please, see: #637

@jhgorse, May I mark this issue as solved? Thanks

[jhgorse]

Yes, please. This ticket is resolved.

Thank you for the update.

Cheers,
Joe