Flag warnings show intermediate hscpp filenames on SmartOS

Sun Jan 10 20:08:11 UTC 2016

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 at 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 at 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 at 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:
>>> https://gcc.gnu.org/onlinedocs/gcc/Spec-Files.html
>>>
>>> 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 at 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 at 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 at gmail.com
>>>>> > <mailto:alain.odea at gmail.com>> wrote:
>>>>> >
>>>>> >     Thanks for the clarification. I understand now.
>>>>> >     On Thu, Dec 31, 2015 at 16:52 Karel Gardas <
>>>>> karel.gardas at centrum.cz
>>>>> >     <mailto:karel.gardas at 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
>>>>> >
>>>>>
>>>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/ghc-devs/attachments/20160110/885ef2ca/attachment-0001.html>