[petsc-dev] COPTFLAGS

[Barry Smith]

  I likely changed it when I got frustrated with something OpenMPI did (since that was changed at the same time). As the commit message says it can be reverted if bad things happen.


On Nov 12, 2013, at 11:37 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:

> Passing COPTFLAGS currently causes your flags to be passed _prior_ to
> the flags that get added in compilerOptions.py.  This makes ./configure
> COPTFLAGS='-Og -g' useless since -O0 gets passed afterward, for example.
> 
> https://bitbucket.org/petsc/petsc/commits/e3218094707942d5674f57c17eb63a9af846a945
> 
>> commit e3218094707942d5674f57c17eb63a9af846a945
>> Author: Barry Smith <bsmith at mcs.anl.gov>
>> Date:   Sat Mar 17 22:47:44 2012 -0500
>> 
>>    added -fno-inline for better debugging with gnu compilers; take it out if it breaks something
>> 
>>    Hg-commit: cee000f4e8f56981f3611284aa810e3c0419aa10
>> 
>> 	Modified   config/compilerOptions.py
>> diff --git a/config/compilerOptions.py b/config/compilerOptions.py
>> index e619c8e..612cb3f 100644
>> --- a/config/compilerOptions.py
>> +++ b/config/compilerOptions.py
>> @@ -22,6 +22,8 @@ class CompilerOptions(config.base.Configure):
>>         if self.framework.argDB['with-gcov']:
>>           flags.extend(['-fprofile-arcs', '-ftest-coverage'])
>>         flags.append('-g3')
>> +        flags.append('-fno-inline')
> 
>       -fno-inline
>           Do not expand any functions inline apart from those marked with the
>           "always_inline" attribute.  This is the default when not optimizing.
> 
> I.e., this option should have no effect.
> 
>> +        flags.append('-O0')
> 
> This is the default and overrides COPTFLAGS since it comes later.
> 
> I would guess this was added to compensate for MPICH putting its CFLAGS
> into the compiler wrappers (you need MPICHLIB_CFLAGS to avoid it), so
> that "mpicc somefile.c" often defaults to high optimization.  That
> behavior is bad and I agree that we need to work around it somehow, but
> the fix in this patch was not applied to getCxxFlags or getFortranFlags.
> 
> The way I see, it, we can exit early when the user specifies COPTFLAGS
> 
> diff --git i/config/BuildSystem/config/compilerOptions.py w/config/BuildSystem/config/compilerOptions.py
> index dadc5fb..2a3cfa0 100644
> --- i/config/BuildSystem/config/compilerOptions.py
> +++ w/config/BuildSystem/config/compilerOptions.py
> @@ -14,6 +14,9 @@ class CompilerOptions(config.base.Configure):
>       except:
>         pass
> 
> +    if bopt and 'COPTFLAGS' in self.framework.argDB:
> +      return []
> +
>     flags = []
>     # GNU gcc
>     if config.setCompilers.Configure.isGNU(compiler) or config.setCompilers.Configure.isClang(compiler):
> 
> and we can add -O0 to the other languages
> 
> @@ -96,6 +101,7 @@ class CompilerOptions(config.base.Configure):
>           flags.extend(['-fprofile-arcs', '-ftest-coverage'])
>         # -g3 causes an as SEGV on OSX
>         flags.append('-g')
> +        flags.append('-O0') # MPICH puts CXXFLAGS into wrappers, so ensure that we do not use optimization
>       elif bopt in ['O']:
>         if os.environ.has_key('USER'):
>           flags.append('-O')
> 
> (similar for Fortran).  But this is also imperfect because some people
> use non-Gnu compilers.
> 
> Is there a clean solution?
> 
> 
>>       elif bopt == 'O':
>>         flags.append('-O')
>>     else:
>> 	Modified   config/packages/MPI.py
>> diff --git a/config/packages/MPI.py b/config/packages/MPI.py
>> index 260acab..2328eb9 100644
>> --- a/config/packages/MPI.py
>> +++ b/config/packages/MPI.py
>> @@ -11,7 +11,7 @@ from stat import *
>> class Configure(config.package.Package):
>>   def __init__(self, framework):
>>     config.package.Package.__init__(self, framework)
>> -    self.download_openmpi   = ['http://www.open-mpi.org/software/ompi/v1.5/downloads/openmpi-1.5.4.tar.gz']
>> +    self.download_openmpi   = ['http://www.open-mpi.org/software/ompi/v1.4/downloads/openmpi-1.4.4.tar.gz']
>>     self.download_mpich     = ['http://www.mcs.anl.gov/research/projects/mpich2/downloads/tarballs/1.4.1p1/mpich2-1.4.1p1.tar.gz']
>>     self.download           = ['redefine']
>>     self.functions          = ['MPI_Init', 'MPI_Comm_create']
>> 
>>