Re: PIC flags not found for mpif77(ifort)

[Ralf Wildenhues]

Hello Christian,

* Christian Rössel wrote on Fri, Dec 10, 2010 at 02:56:51PM CET:
> ./configure --enable-shared F77=mpif77 ...
> 
> where mpif77 translates to
> 
> ifort -I/opt/parastation/mpi2-intel/include
> -L/opt/parastation/mpi2-intel/lib -Wl,-rpath
> -Wl,/opt/parastation/mpi2-intel/lib -lmpich -lpthread
> -L/opt/parastation/lib64 -Wl,-rpath,/opt/parastation/lib64
> -Wl,--enable-new-dtags -lpscom -lrt
> 
> configure fails in finding PIC flags (mpicc (icc) and mpicxx (icpc) PIC
> flags are discovered though):
> 
> configure:17627: checking for mpif77 option to produce PIC
> configure:17899: result:
> 
> There is no more output concerning the PIC flags in config.log.
> With F77=ifort everything works as expected:
> 
> configure:16805: checking for ifort option to produce PIC
> configure:17077: result: -fPIC

Yeah, that's because libtool.m4 macros partly match by name, unless the
compiler claims to be GCC.  A bit dumb, sure, but it's not easy to avoid
because portable testing of these flags is not trivial.  We might have
to think about a more general way to extract the compiler name from an
MPI driver (-show and -showme come to mind).

For the moment you should be able to work around it using
  configure lt_cv_prog_compiler_pic_F77=-fPIC \
            lt_cv_prog_compiler_pic_FC=-fPIC \

but I'm not sure if you also need fixes for missing -static and -Wl,
flags (lt_prog_compiler_wl_F77 and lt_prog_compiler_static_F77 ...).
This requires Libtool >= 2.4.

Alternatively, the untested patch below should help as well.  Can you
try it out?

Thanks for the report,
Ralf

    Fix PIC flags with mpif77 using ifort on GNU/Linux.
    
    * libltdl/m4/libtool.m4 (_LT_COMPILER_PIC) [linux]:
    Match Intel compiler also using $CC -V output, to avoid false
    negatives with compiler drivers like mpif77.
    Report by Christian Rössel.

diff --git a/libltdl/m4/libtool.m4 b/libltdl/m4/libtool.m4
index 1f61140..e735c75 100644
--- a/libltdl/m4/libtool.m4
+++ b/libltdl/m4/libtool.m4
@@ -4338,6 +4338,11 @@ m4_if([$1], [CXX], [
          _LT_TAGVAR(lt_prog_compiler_static, $1)='-Bstatic'
          _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
          ;;
+        *Intel*\ [CF]*Compiler*)
+         _LT_TAGVAR(lt_prog_compiler_wl, $1)='-Wl,'
+         _LT_TAGVAR(lt_prog_compiler_pic, $1)='-fPIC'
+         _LT_TAGVAR(lt_prog_compiler_static, $1)='-static'
+         ;;
        esac
        ;;
       esac