Lift instance cause GHC build error: unknown symbol with CFFI

[Minh Le]

Hi everyone,
I’m building a floating-point library for Clash that uses FloPoCo. The
library integrates with the MPFR library via the hmpfr Haskell
bindings to perform accurate software simulations of floating-point
operations.
I’ve encountered build errors related to linking the MPFR library:
Windows:
unknown symbol 'mpfr_add' in Arithmetic.o.
Linux:
symbol lookup error: undefined symbol 'mpfr_custom_get_size_wrap'.
Interestingly, cabal repl works as expected, but cabal build fails.
This suggests a linking issue specific to the build process.
Steps to Reproduce
Clone the repository: https://github.com/yourcomrade/FloPoCoFloat.
Install MPFR:
Windows: pacman -S mingw-w64-clang-x86_64-mpfr
Linux: sudo apt install libmpfr6 libmpfr-dev
Check out the Error_branch.
Build the project using cabal build.
Expected Behavior
The project should compile without errors. Notably, if cabal build
fails, I would expect cabal repl to fail too, but that’s not the case.
Additional Info
OS: Windows 11, Ubuntu WSL 5.15
Tools: GHC 9.8.2, Cabal 3.10.3, GCC 11.4
Relevant discussion: Cabal issue: https://github.com/haskell/cabal/issues/10651
I have a discussion with Cabal maintainer and he suspects that is GHC
linking issue.
Does anyone have insights into resolving this issue? Any help would be
appreciated.
Kind regards,
Minh