https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88772
--- Comment #5 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> For 64bits the result is "no":
> 643 configure:4751: checking whether the compiler is configured for
> setjmp/longjmp exceptions
> 644 configure:4769: x86_64-w64-mingw32-gcc
> -L/home/andoni/mingw/windows/multilib/x86_64-w64-mingw32/lib
> -L/home/andoni/mingw/windows/multilib/mingw/lib -isystem /home
> /andoni/mingw/windows/multilib/x86_64-w64-mingw32/include -isystem
> /home/andoni/mingw/windows/multilib/mingw/include -c -Wall -g -O2
> -DWINVER=0x0600 -D_WIN32_ WINNT=0x0600 conftest.c >&5
> 645 conftest.c: In function 'main':
> 646 conftest.c:30:5: warning: unused variable 'i' [-Wunused-variable]
> 647 int i;
> 648 ^
> 649 configure:4769: $? = 0
> 650 configure:4776: result: no
As expected.
> for 32 bits the result is "yes":
> 631 configure:4751: checking whether the compiler is configured for
> setjmp/longjmp exceptions
> 632 configure:4769: x86_64-w64-mingw32-gcc
> -L/home/andoni/mingw/windows/multilib/x86_64-w64-mingw32/lib
> -L/home/andoni/mingw/windows/multilib/mingw/lib -isystem /home
> /andoni/mingw/windows/multilib/x86_64-w64-mingw32/include -isystem
> /home/andoni/mingw/windows/multilib/mingw/include -m32 -c -Wall -g -O2
> -DWINVER=0x0600 -D_WIN 32_WINNT=0x0600 conftest.c >&5
> 633 conftest.c:25:11: error: unknown type name 'this'
> 634 this will fail
> 635 ^~~~
> 636 conftest.c:25:21: error: expected '=', ',', ';', 'asm' or
> '__attribute__' before 'fail'
> 637 this will fail
> 638 ^~~~
> 639 configure:4769: $? = 1
> [...]
> 674 configure:4776: result: yes
As expected.
> For 32 bits the final EH model being used is Dwarf2:
>
> 340 # Additional sources to handle exceptions; overridden by targets as
> needed.
> 341 LIB2ADDEH = $(srcdir)/unwind-dw2.c $(srcdir)/unwind-dw2-fde.c \
> 342 $(srcdir)/unwind-sjlj.c $(srcdir)/unwind-c.c
>
>
> What I understand is happening in a multilib build is that for 64 it chooses
> SEH because ac_cv_sjlj_exceptions is not "yes" but for 32, it chooses dw2
> instead of SJLJ for the same reason, because ac_cv_sjlj_exceptions is not
> "yes":
> if test x$ac_cv_sjlj_exceptions = xyes; then
> tmake_eh_file="i386/t-sjlj-eh"
> elif test "${host_address}" = 32; then
> # biarch -m32 with --disable-sjlj-exceptions
> tmake_eh_file="i386/t-dw2-eh"
> md_unwind_header=i386/w32-unwind.h
> else
> tmake_eh_file="i386/t-seh-eh"
> fi
But you said above that the result is "yes" for 32-bit, so how come the test:
x$ac_cv_sjlj_exceptions = xyes;
is false? Does it help to rewrite it into just:
$ac_cv_sjlj_exceptions = yes;
like in libgcc/configure.ac?
