Can we combine CXXPPFLAGS and CXXFLAGS into one CXXFLAGS? --Junchao Zhang
On Tue, Mar 23, 2021 at 11:38 AM Patrick Sanan <patrick.sa...@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.zamp...@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 <ba...@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@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 >> > > > >> > > > >> > > > >> > > >> > > >> > >> >> >