cpphs doesn't currently work for compiling GHC.  libraries/base/GHC/Natural.hs uses a macro with arguments inside an if defined preprocessor expression and cpphs tries to expand the macro and errors since there are no arguments provided.

This is non-compliant if cpphs is trying to be a C99 preprocessor:
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf
6.10.1/1 Conditional Inclusion pg 148 clearly indicates that the token after defined or within defined ( ) is an identifier, not a macro to be expanded.



On Sun, Jan 10, 2016 at 2:14 AM Alain O'Dea <alain.odea@gmail.com> wrote:
Progress Update:
1. fixing CPP fixes the majority of the remaining test failures
2. cpphs builds and runs successfully on SmartOS
3. --with-hs-cpp-flags='-specs=overridecpp.spec" can be used in lieu of a wrapper script
3. I am running some experiments with cpphs to see how it works
4. I will run some experiments with hs-cpp-flags and gcc to see how that goes (it would be a smaller impact change on GHC to include and reference a spec file)

On Fri, Jan 1, 2016 at 5:32 PM Alain O'Dea <alain.odea@gmail.com> wrote:
Okay Karel.  I have a solution that works to make T2464 pass.

Create overridecpp.spec:

*cpp:
%{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}

Create ghc-cpp and make it executable:

#!/bin/bash
gcc -spec=/path/to/overridecpp.spec $@

Configure and make GHC with ghc-cpp and run T2464:

./configure --with-hs-cpp=/path/to/ghc-cpp
make -j8
make TEST=T2464 test

This should work on Solaris 11 as well.

So GHC could ship a GCC Specs file like this and that wrapper script as an interim solution.  In the interim I'll include these as patches in PKGSRC and get a GHC 7.10.3 built with them applied.  I'm going to hold off on PKGSRC stuff until I get fixes for more of the failing tests though.

Does this seem like a reasonable solution to you?

On Fri, Jan 1, 2016 at 4:58 PM Alain O'Dea <alain.odea@gmail.com> wrote:
Actually Karel, if "gcc -dumpspecs" shows you that same -P as I get you can override it with spec files as described here:

I think this means that you could specify "gcc -specs=/path/to/overridecpp.spec" as --with-hs-cpp when building GHC.  I'm trying that now.  I've already gotten a strawman example based on your post to the GCC list working, and I'm going to try to expand on it.

On Fri, Jan 1, 2016 at 3:08 PM Alain O'Dea <alain.odea@gmail.com> wrote:
True, but I'd still like to find a mutual solution since we're both somewhat at the edge of the supported landscape for GHC.

Is installing cpphs and configuring GHC to use that an option on Solaris 11? I haven't built cpphs successfully on SmartOS yet. Supplying a custom C preprocessor may be your best bet and using GCC 3.4's works for you. If I can get cpphs working that may be the common ground needed to keep Illumos and Solaris support from diverging.

On Fri, Jan 1, 2016 at 7:52 AM Karel Gardas <karel.gardas@centrum.cz> wrote:

Alain,

indeed, on SmartOS you are free to modify the supplied GCC so the fix to
remove -P is most natural one. On the other hand I'm not so lucky with
binary Solaris 11.x distribution provided by Oracle so I need to use not
so clean and nice workarounds...

Karel

On 01/ 1/16 12:17 AM, Alain O'Dea wrote:
> cpphs isn't a direct option.  It won't install on SmartOS with Cabal.
> GCC 4.7 is the earliest GCC supported so I'll have to try something else
> for SmartOS.
>
> It looks like the GCC Specs are the problem.
>
> On Ubuntu the Spec for cpp is:
>
> *cpp:
> %{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}
>
> On SmartOS the Spec for cpp is:
>
> *cpp:
> %{,assembler-with-cpp:-P} %(cpp_subtarget)
>
> I think this is how the -P gets injected.  I think this is correctable.
> I had a similar issue with -std=c99 which is the default for C compiling
> on Ubuntu but not on SmartOS leading to issues with compiling source
> that isn't old school C (like persistent-sqlite).
>
> Anyways I must retire from this and entertain my guests.  Happy New Year
> folks.
>
>
> On Thu, Dec 31, 2015 at 5:19 PM Alain O'Dea <alain.odea@gmail.com
> <mailto:alain.odea@gmail.com>> wrote:
>
>     Thanks for the clarification. I understand now.
>     On Thu, Dec 31, 2015 at 16:52 Karel Gardas <karel.gardas@centrum.cz
>     <mailto:karel.gardas@centrum.cz>> wrote:
>
>         On 12/31/15 07:41 PM, Alain O'Dea wrote:
>          > Yes. I can do that.
>          >
>          > On SmartOS it may not be GCC 3.4.3 causing this. I see this
>         on GCC 4.7.x
>          > through 4.9.x. The paths to gcc on SmartOS also differ. I'll
>         have to
>          > verify that as part of checking this.
>
>         This is misunderstanding. GCC 3.4.3 provides *correct* CPP behavior,
>         while all 4.x provides broken CPP. That means as a workaround
>         when GCC
>         3.4.3 is installed I set it as GHC's CPP automatically on
>         Solaris. When
>         it is not available, then GHC behaves like you've seen when
>         using CPP...
>
>         Hopefully this is more clear now,
>
>         Karel
>