How to force -fPIC on package builds?

[Boespflug, Mathieu]

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 <djsamperi at gmail.com> 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.
>
> On Sat, Aug 13, 2016 at 10:22 AM, Dominick Samperi <djsamperi at gmail.com>
> wrote:
> > 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 <m at tweag.io> wrote:
> >> Hi Dominick,
> >>
> >> which version of Fedora Linux are you on? The -fPIC message from the
> linker
> >> 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 <djsamperi at gmail.com>
> wrote:
> >>>
> >>> Hello,
> >>>
> >>> I am getting relocation errors when building an executable
> >>> (specifically, the "H"
> >>> executable -- part of haskellR) under Fedora Linux, and the message
> says
> >>> 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 at haskell.org
> >>> http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
> >>
> >>
>
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