[petsc-dev] configureLibrary fails for c++11 projects
Stefano Zampini
stefano.zampini at gmail.com
Wed Mar 24 03:35:49 CDT 2021
I will open an MR then
Il giorno mar 23 mar 2021 alle ore 22:42 Matthew Knepley <knepley at gmail.com>
ha scritto:
>
> On Tue, Mar 23, 2021 at 1:15 PM Junchao Zhang <junchao.zhang at gmail.com>
> wrote:
>
>> Can we combine CXXPPFLAGS and CXXFLAGS into one CXXFLAGS?
>>
>
> No. There are compiler-only flags.
>
> Matt
>
>
>> --Junchao Zhang
>>
>>
>> On Tue, Mar 23, 2021 at 11:38 AM Patrick Sanan <patrick.sanan at gmail.com>
>> wrote:
>>
>>> I had a related (I think) issue trying to build with Kokkos. Those
>>> headers throw an #error if they're expecting OpenMP and the compiler
>>> doesn't have the OpenMP flag. I have an open MR here (number 60^2!) which
>>> thus adds the OpenMP flag to the CXXPPFLAGS:
>>> https://gitlab.com/petsc/petsc/-/merge_requests/3600
>>>
>>>
>>> My collaborator at CSCS was testing with the latest Kokkos and ran into
>>> an even hairier version of this problem trying to use CUDA - the Kokkos
>>> headers now apparently check that you're using nvcc. He has some workaround
>>> which I'll review and hopefully be able to submit.
>>>
>>>
>>> Am 23.03.2021 um 17:04 schrieb Stefano Zampini <
>>> stefano.zampini at gmail.com>:
>>>
>>> The check fails within buildsystem when running mpicc -E (which uses
>>> CXXPPFLAGS) The package header needs c++11 to be included properly.
>>> C++11 is also needed at preprocessing time
>>>
>>> Il Mar 23 Mar 2021, 18:59 Satish Balay <balay at mcs.anl.gov> ha scritto:
>>>
>>>> -std=cxx11 for sure is a compile flag. But don't really know if its
>>>> also needed at pre-process stage and/or at link stage.
>>>>
>>>> And for compile stage both CXXFLAGS and CXXPPFLAGS should get
>>>> used. [PETSc makefiles make sure this is the case]
>>>>
>>>> And for link stage CXXFLAGS and LDFLAGS get used [but then sometimes
>>>> we have CLINKER, and FLINKER - and they certainly don't use CXXFLAGS -
>>>> so -std=cxx11 isn't really needed at link time?
>>>>
>>>> So the previous default of CXXPPFLAGS=-std=cxx11 looks reasonable to me.
>>>>
>>>> However if this project is not using PETSc makefiles - it should make
>>>> sure all compile flags are grabbed.
>>>>
>>>> # lib/petsc/conf/variables
>>>> PETSC_CXXCPPFLAGS = ${PETSC_CC_INCLUDES} ${PETSCFLAGS}
>>>> ${CXXPP_FLAGS} ${CXXPPFLAGS}
>>>> CXXCPPFLAGS = ${PETSC_CXXCPPFLAGS}
>>>> PETSC_CXXCOMPILE_SINGLE = ${CXX} -o $*.o -c ${CXX_FLAGS} ${CXXFLAGS}
>>>> ${CXXCPPFLAGS}
>>>>
>>>> # lib/petsc/conf/rules
>>>> .cpp.o .cxx.o .cc.o .C.o:
>>>> ${PETSC_CXXCOMPILE_SINGLE} `pwd`/$<
>>>>
>>>> # gmakefile.test
>>>> PETSC_COMPILE.cxx = $(call quiet,CXX) -c $(CXX_FLAGS) $(CXXFLAGS)
>>>> $(CXXCPPFLAGS) $(CXX_DEPFLAGS)
>>>>
>>>> # lib/petsc/conf/test
>>>> LINK.cc = $(CXXLINKER) $(CXX_FLAGS) $(CXXFLAGS) $(CXXCPPFLAGS)
>>>> $(LDFLAGS)
>>>>
>>>> Satish
>>>>
>>>>
>>>> On Tue, 23 Mar 2021, Junchao Zhang wrote:
>>>>
>>>> > I would rather directly change the project to use CXXFLAGS instead of
>>>> > CXXPPFLAGS.
>>>> >
>>>> > --Junchao Zhang
>>>> >
>>>> >
>>>> > On Tue, Mar 23, 2021 at 10:01 AM Satish Balay via petsc-dev <
>>>> > petsc-dev at mcs.anl.gov> wrote:
>>>> >
>>>> > > On Tue, 23 Mar 2021, Stefano Zampini wrote:
>>>> > >
>>>> > > > Just tried out of main, and and the include tests of a c++11
>>>> project fail
>>>> > > > Below my fix, if we agree on, I'll make a MR
>>>> > > >
>>>> > > > diff --git a/config/BuildSystem/config/compilers.py
>>>> > > > b/config/BuildSystem/config/compilers.py
>>>> > > > index c96967e..44e4657 100644
>>>> > > > --- a/config/BuildSystem/config/compilers.py
>>>> > > > +++ b/config/BuildSystem/config/compilers.py
>>>> > > > @@ -527,6 +527,8 @@ class Configure(config.base.Configure):
>>>> > > > if self.setCompilers.checkCompilerFlag(flag, includes,
>>>> > > > body+body14):
>>>> > > > newflag = getattr(self.setCompilers,LANG+'FLAGS') + '
>>>> ' +
>>>> > > flag #
>>>> > > > append flag to the old
>>>> > > > setattr(self.setCompilers,LANG+'FLAGS',newflag)
>>>> > > > + newflag = getattr(self.setCompilers,LANG+'PPFLAGS') +
>>>> ' ' +
>>>> > > flag
>>>> > > > # append flag to the old
>>>> > > > + setattr(self.setCompilers,LANG+'PPFLAGS',newflag)
>>>> > >
>>>> > >
>>>> > >
>>>> https://gitlab.com/petsc/petsc/commit/ead1aa4045d7bca177e78933b9ca25145fc3c574
>>>> > >
>>>> > > self.setCompilers.CXXPPFLAGS += ' ' + flag
>>>> > > newflag = getattr(self.setCompilers,LANG+'FLAGS') + ' ' +
>>>> flag #
>>>> > > append flag to the old
>>>> > > setattr(self.setCompilers,LANG+'FLAGS',newflag)
>>>> > >
>>>> > > So the old code was setting 'PPFLAGS' - but this commit changed to
>>>> > > 'FLAGS'. Maybe this flag is needed at both compile time and link
>>>> time?
>>>> > >
>>>> > > So this project is somehow using CXXPPFLAGS - but not CXXFLAGS?
>>>> > >
>>>> > > I'm fine with adding it to PPFLAGS - duplicate listing hopefully
>>>> shouldn't
>>>> > > cause grief.
>>>> > >
>>>> > > Satish
>>>> > >
>>>> > > > cxxdialect = 'C++14'
>>>> > > > self.addDefine('HAVE_'+LANG+'_DIALECT_CXX14',1)
>>>> > > > self.addDefine('HAVE_'+LANG+'_DIALECT_CXX11',1)
>>>> > > > @@ -546,6 +548,8 @@ class Configure(config.base.Configure):
>>>> > > > if self.setCompilers.checkCompilerFlag(flag, includes,
>>>> body):
>>>> > > > newflag = getattr(self.setCompilers,LANG+'FLAGS') + '
>>>> ' +
>>>> > > flag #
>>>> > > > append flag to the old
>>>> > > > setattr(self.setCompilers,LANG+'FLAGS',newflag)
>>>> > > > + newflag = getattr(self.setCompilers,LANG+'PPFLAGS') +
>>>> ' ' +
>>>> > > flag
>>>> > > > # append flag to the old
>>>> > > > + setattr(self.setCompilers,LANG+'PPFLAGS',newflag)
>>>> > > > cxxdialect = 'C++11'
>>>> > > > self.addDefine('HAVE_'+LANG+'_DIALECT_CXX11',1)
>>>> > > > break
>>>> > > >
>>>> > > >
>>>> > > >
>>>> > >
>>>> > >
>>>> >
>>>>
>>>>
>>>
>
> --
> What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> -- Norbert Wiener
>
> https://www.cse.buffalo.edu/~knepley/
> <http://www.cse.buffalo.edu/~knepley/>
>
--
Stefano
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