Re: How to force -fPIC on package builds?

I was able to reproduce in a docker container and tracked down the source of the issue: https://github.com/tweag/HaskellR/issues/257 The executive summary is that if Cabal is asking hsc2hs to link to a dynamic library, then it should pass --cflag=-fPIC to hsc2hs. Otherwise hsc2hs might fail, because then it might be impossible to link the temporary object files that it creates with the shared library. A workaround is to set "cc-options: -fPIC" in the .cabal file. But in my mind this is probably a Cabal bug. -- Mathieu Boespflug Founder at http://tweag.io. On 14 August 2016 at 06:12, Dominick Samperi wrote:

I should add that H builds and runs nicely under Windows and MacOS (using ghc 8.0.1), so this is indeed a Fedora Linux issue.

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Hello Mathieu,

I'm using Fedora 23. The default Haskell Platform here provides ghc 7.8.4, and this seems to have even more problems. Thus I have been trying to use ghc 8.0.1 compiled from source. I think the red herring bit may apply to 32 bit builds, but I am attempting a 64 bit build. The problem may be related to the way modules are randomly relocated for security reasons, Fedora security policies, and confusion/bugs in the linker(s).

Cheers, Dominick

On Sat, Aug 13, 2016 at 7:43 AM, Boespflug, Mathieu wrote:

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Hi Dominick,

which version of Fedora Linux are you on? The -fPIC message from the

On Sat, Aug 13, 2016 at 10:22 AM, Dominick Samperi wrote: linker

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may well be a red herring. AFAIR generating PIC is the default in GHC, at least for dynamic libraries.

Best,

-- Mathieu Boespflug Founder at http://tweag.io.

On 13 August 2016 at 05:55, Dominick Samperi wrote:

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Hello,

I am getting relocation errors when building an executable (specifically, the "H" executable -- part of haskellR) under Fedora Linux, and the message

says

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to "recompile with -fPIC".

The FAQ associated with H suggests that I switch to the gold linker (ld.gold) due to bugs in the default linker (ld.bfd), but this only changes the wording of the relocation error messages.

I have tried several strategies for satisfying the -fPIC requirement: 1. In cabal files I insert cc-options: and ghc-options: lines including -fPIC 2. To the 'cabal install' command line I add: --ghc-option=-fPIC --hsc2hs-option=-cflag=-fPIC 3. When building ghc 8.0.1 from source I modify config.mk by including: CONF_CC_OPTS += -fPIC SRC_HSC2HS_OPTS += --cflag=-fPIC CONF_CC_OPTS_STAGE0 = -fno-stack-protector -fPIC [same for STAGE1 and STAGE2]

All of this doesn't fix the problem, and the error messages still say "recompile with -fPIC".

This may be a bug, but I'm not sure where. Any ideas?

Thanks, Dominick _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs