FX Coudert wrote:
> The idea is that libbacktrace should be able to build on all targets, at
> least in a minimally-functional form:
> https://gcc.gnu.org/ml/gcc/2015-08/msg00038.html
> libgfortran should continue to build on all targets, even those that
> don't have an mmap().
>
> I see that there is a test in libbacktrace/configure.ac for mmap(), but
> apparently it fails on your system:
Ah, I see. On the SPU, we do have an sys/mman.h header file, which provides
a "mmap_eaddr" routine used to map files into the DMA address space, and
associated mmap flags. That's why the test gets confused.
> So this should be the place to patch things up. Relying on the presence of
> <sys/mman.h> is apparently not restrictive enough. Maybe we could use a
> AC_EGREP_HEADER test, as is currently done for dl_interate_phdr()?
Hmm, that seems tricky, since the SPU sys/mman.h file contains the prototype
for mmap_eaddr, and the string "mmap" in various comments ...
I guess we can always just hard-code that SPU does not have mmap, similar
to how Solaris is hard-coded to not have dl_iterate_phdr.
Would something like the below be OK (if it passes testing)?
Thanks,
Ulrich
Index: libbacktrace/configure.ac
===================================================================
--- libbacktrace/configure.ac (revision 227056)
+++ libbacktrace/configure.ac (working copy)
@@ -273,6 +273,12 @@ else
# When built as a GCC target library, we can't do a link test. We
# simply assume that if we have mman.h, we have mmap.
have_mmap=yes
+ case "${host}" in
+ spu-*-*)
+ # The SPU does not have mmap, but it has a sys/mman.h header file
+ # containing "mmap_eaddr" and the mmap flags, confusing the test.
+ have_mmap=no ;;
+ esac
else
AC_CHECK_FUNC(mmap, [have_mmap=yes], [have_mmap=no])
fi
--
Dr. Ulrich Weigand
GNU/Linux compilers and toolchain
ulrich.weig...@de.ibm.com
