I recently tried a cross-build from sparc-sun-solaris2.12 to
i386-pc-solaris2.12 (with cross-binutils and gas, but the native ld
which has been a cross-linker for quite some time). The build failed in
libstdc++-v3 like this:
/vol/gcc/src/hg/trunk/local/libstdc++-v3/libsupc++/new_opa.cc:62:46: error: ‘void* aligned_alloc(std::size_t, std::size_t)’ conflicts with a previous declaration
aligned_alloc (std::size_t al, std::size_t sz)
^
In file included from /var/gcc/sysroot/i386/usr/include/stdlib.h:13:0,
from /var/gcc/cross/i386-pc-solaris2.12/obj/gcc-8.0.0-20170516/12-gcc-gas/i386-pc-solaris2.12/libstdc++-v3/include/cstdlib:75,
from /var/gcc/cross/i386-pc-solaris2.12/obj/gcc-8.0.0-20170516/12-gcc-gas/i386-pc-solaris2.12/libstdc++-v3/include/stdlib.h:36,
from /vol/gcc/src/hg/trunk/local/libstdc++-v3/libsupc++/new_opa.cc:27:
/var/gcc/sysroot/i386/usr/include/iso/stdlib_c99.h:79:14: note: previous declaration ‘void* std::aligned_alloc(std::size_t, std::size_t)’
extern void *aligned_alloc(size_t, size_t);
^~~~~~~~~~~~~
/vol/gcc/src/hg/trunk/local/libstdc++-v3/libsupc++/new_opa.cc: In function ‘void* operator new(std::size_t, std::align_val_t)’:
/vol/gcc/src/hg/trunk/local/libstdc++-v3/libsupc++/new_opa.cc:103:57: error: call of overloaded ‘aligned_alloc(std::size_t&, std::size_t&)’ is ambiguous
while (__builtin_expect ((p = aligned_alloc (align, sz)) == 0, false))
^
In file included from /var/gcc/sysroot/i386/usr/include/stdlib.h:13:0,
from /var/gcc/cross/i386-pc-solaris2.12/obj/gcc-8.0.0-20170516/12-gcc-gas/i386-pc-solaris2.12/libstdc++-v3/include/cstdlib:75,
from /var/gcc/cross/i386-pc-solaris2.12/obj/gcc-8.0.0-20170516/12-gcc-gas/i386-pc-solaris2.12/libstdc++-v3/include/stdlib.h:36,
from /vol/gcc/src/hg/trunk/local/libstdc++-v3/libsupc++/new_opa.cc:27:
/var/gcc/sysroot/i386/usr/include/iso/stdlib_c99.h:79:14: note: candidate: ‘void* std::aligned_alloc(std::size_t, std::size_t)’
extern void *aligned_alloc(size_t, size_t);
^~~~~~~~~~~~~
/vol/gcc/src/hg/trunk/local/libstdc++-v3/libsupc++/new_opa.cc:62:1: note: candidate: ‘void* aligned_alloc(std::size_t, std::size_t)’
aligned_alloc (std::size_t al, std::size_t sz)
^~~~~~~~~~~~~
make[4]: *** [Makefile:936: new_opa.lo] Error 1
It turns out that currently crossconfig.m4 has a static list of
AC_DEFINEs for *-solaris*, which is obviously incomplete compared to the
target's features. Instead of manually fixing this, it seems the way to
go is follow the lead of the Linux etc. targets and just perform the
link tests which are skipped in configure.ac for the !GLIBCXX_IS_NATIVE
case since they *do* work reliably in this case. This is just what this
patch does: treat Solaris like the Linux targets and remove the
hardcoded feature list from crossconfig.m4.
This way, config.h is identical between a native build and the cross
above, with the exception of HAVE_SETENV which is equally guarded with
GLIBCXX_IS_NATIVE in acinclude.m4 (GLIBCXX_CONFIGURE_TESTSUITE). Maybe
it's time to somehow refine the GLIBCXX_IS_NATIVE check to allow cross
configurations that *can* perform link tests to run them?