LFortran: --generate-object-code flag breaks lfortran's own examples/project1

When LFortran support was added by !9188 (merged), we hard-coded --generate-object-code in CMAKE_Fortran_COMPILE_OBJECT.

As reported in:

• Debian issue 1091023
• lfortran issue 5944

this flag breaks lfortran's examples/project1 example. The example uses Fortran modules, for which --generate-object-code does not work:

• 5a0908a1 (comment 1478158)
• lfortran issue 2955

However, removing the --generate-object-code flag causes several of CMake's Fortran test cases to fail. We need to figure out how to reconcile these cases.

changed milestone to %3.31.4

added comp:lfortran label

mentioned in merge request !10159 (merged)

removing the --generate-object-code flag causes several of CMake's Fortran test cases to fail.

This is the reason the flag was included in !9188 (merged).

Without --generate-object-code, even a basic project like CMake's Tests/FortranOnly fails to build:

/usr/bin/ld: CMakeFiles/FortranOnly1.dir/testf.f.o: in function `main':
LFortran:(.text+0x7): undefined reference to `hello'
/usr/bin/ld: LFortran:(.text+0xc): undefined reference to `world'

I've updated !10159 (merged) to just add --generate-object-code in individual test cases wherever it is needed.

Cc: @certik @junghans @kmr-srbh

It seems like some use cases need --generate-object-code and others don't, just for basic compiler functionality. What does the flag do, and why does lfortran make end users deal with this when no other Fortran compiler does?

What does the flag do, and why does lfortran make end users deal with this when no other Fortran compiler does?

I posted the motivation at:

https://github.com/lfortran/lfortran/issues/2955#issuecomment-2580861731

We have two modes of compilation. Other compilers typically have just one mode of compilation.

I agree, I think it is possible to automatically generate code for subroutines outside of modules, we are working on it at:

https://github.com/lfortran/lfortran/pull/5953

That should pass the cmake test suite without the flag, so that we can have the flag disabled by default.

Great, thanks for explaining!

closed with merge request !10159 (merged)