[clang] [flang] [flang][Driver] Let the linker fail on multiple definitions of main() (PR #73124)

[Andrzej Warzyński via cfe-commits]

banach-space wrote:

> I see. So Fortran and C interoperability of F2003/F2008 is not supported yet in Flang? 

That's not really what I had in mind. It worked for you so everything that's needed is there, but no upstream testing indicates that you might be the first person trying it. And that nobody has actually tried verifying it and making sure that relevant various bits are integrated in the intended way.

> Those ~100ish regression test cases we have were passing before this PR though. 

That's a lot - I am sorry about that :(

> I think I can copy the source code of one test case here, but it needs to be run manually.

It sounds like you are hitting something fairly fundamental that should be reproducible with a couple of files (C and Fortran), few lines each. And without a repro, it will be very hard to fix that. We could revert this change, but then again - without a simple repro we won't be able to improve this for the future.



https://github.com/llvm/llvm-project/pull/73124