CPP usage in GHC.

Karel Gardas karel.gardas at centrum.cz
Tue Aug 12 21:12:01 UTC 2014

Actually probably not debris leftover but needed code. I just removed -x 
assembler-with-cpp and got this:

gcc: ghc/Main.hs: linker input file unused because linking not done

so we definitely need some -x to set language even for GNU C. Tested 
also with old 3.4.x. From langs available, assembler-with-cpp looks like 
the best option unfortunately...


On 08/12/14 01:35 AM, Carter Schonwald wrote:
> Oooooo.  Then it's possibly debris leftover from Austin's initial clang
> compatibility work predating the improvements via the settings file work.
> I'm Afk right now, but that probably can be safely removed from ghc,
> especially since the configure script for clang cpp adds that anyways
> now I think?  I might be wrong though.
> On Monday, August 11, 2014, Karel Gardas <karel.gardas at centrum.cz
> <mailto:karel.gardas at centrum.cz>> wrote:
>     On 08/11/14 11:18 PM, Carter Schonwald wrote:
>         why should this flag be passed to cpp when invoked on HS files?
>         It'd be
>         easy to expose another field in the settings file for this other
>         invokecation.. though i should look more closely at the use site
>         before
>         opinining :)
>     Hmm, isn't doCpp function what's invoked when cpp is invoked for HS
>     files? If so, then -x assembler-with-cpp is already used for HS
>     files anyway.
>     Karel
>         On Mon, Aug 11, 2014 at 4:27 PM, Karel Gardas
>         <karel.gardas at centrum.cz
>         <mailto:karel.gardas at centrum.cz>> wrote:
>              On 08/11/14 08:48 PM, Carter Schonwald wrote:
>                  What i'm hearing you say is we actually need TWO sets
>         of CPP
>                  flags, one
>                  for normal haskell, and another for the CPP used on the
>         assembler?
>                  wheres this hardcoding?
>              DriverPipeline.hs -- grep for "assembler-with-cpp" and you
>         will find it.
>              IMHO best would be to move this "-x assembler-with-cpp"
>         into the
>              hs-cpp-flags managed by configure. This way it may be even
>         possible
>              to use system supplied plain cpp instead of cpp builtinto
>         GNU C.
>              Karel

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