Re: [OMPI users] OMPI users] Compiling Open MPI for Cross-Compilation

[Benjamin Brock]

Yeah, I just noticed that Open MPI was giving me all x86_64 binaries with
the configuration flags

./configure --host=riscv64-unknown-linux --enable-static --disable-shared
--disable-dlopen --enable-mca-no-build=patcher-overwrite
--prefix=/home/ubuntu/src/ben-build/openmpi

and was very confused.

I thought that the expected behavior for configure scripts was that setting
--host=[myarch]-linux-gnu will tell the compiler to use the
[myarch]-linux-gnu-[gcc,g++,etc.] compiler when building software that will
run on the host arch.  This is what other software I've encountered (e.g.
MPICH) does.

Basically, I want the `orterun` binaries to be compiled with
riscv64-unknown-linux-[gcc,g++] compilers and the `mpi[cc,c++]` binaries to
be compiled with x86_64-linux-gnu-[gcc,g++] and configured to *use*
riscv64-unknown-linux-[gcc,g++] when compiling programs (because, like
`orterun`, programs compiled with `mpi[cc,c++]` will run on the host arch).

Can I get this by just setting [CC,CXX]=riscv64-unknown-linux-[gcc,g++],
etc.?

Ben
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Re: [OMPI users] OMPI users] Compiling Open MPI for Cross-Compilation

[gilles]

 Benjamin,



i noticed you build Open MPI with plain gcc.

is gcc a cross compiler ?

if not, you have to tell configure to use the cross compilers (and cross 
assembler and linker too)

for example

configure CC=crosscompiler ...

you might be able to achieve this with standard gcc and the right -march 
flag

for example

configure CFLAGS=-march=riscv64



Cheers,



Gilles

- Original Message -

Here's my config.log.

Recompiling now with those options.

Ben
 
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Re: [OMPI users] OMPI users] Compiling Open MPI for Cross-Compilation

[Gilles Gouaillardet]

There is something odd here.

From the configure.m4 of patcher/overwrite

#if !defined(__i386__) && !defined(__x86_64__) && !defined(__PPC__)
#error "platform not supported"
#endif

My guess is that should fail on your arch.

Can you please compress and post your config.log ?

Meanwhile, you can try using these two extra configure options
configure --disable-dlopen --enable-mca-no-build=patcher-overwrite ...


Cheers,

Gilles

Benjamin Brock  wrote:
>> try removing the --target option.
>
>With the configure line
>
>./configure --host=riscv64-unknown-linux --enable-static --disable-shared 
>--prefix=/home/ubuntu/src/ben-build/openmpi
>
>
>It successfully configures, but I now get the error
>
>/home/xiii/Downloads/openmpi-3.0.0/opal/.libs/libopen-pal.a(patcher_overwrite_module.o):
> In function `mca_patcher_overwrite_patch_address':
>patcher_overwrite_module.c:(.text+0x89): undefined reference to 
>`mca_patcher_overwrite_apply_patch'
>collect2: error: ld returned 1 exit status
>Makefile:1844: recipe for target 'orte-clean' failed
>
>
>When trying to compile.
>
>Ben
>
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