On Sat, 30 May 2020 at 02:01, Manfred Schwarb <manfred99@xxxxxx> wrote: > > Hi, > I tried to debug fortran.dg/pr95090.f90, which showed > > f951: internal compiler error: Segmentation fault > 0x83cfe3c ??? > ../sysdeps/i386/start.S:117 > Please submit a full bug report, > with preprocessed source if appropriate. > Please include the complete backtrace with any bug report. > See <https://gcc.gnu.org/bugs/> for instructions. > > > Using GDB (8.3.1), I got > #> f951="`$instdir/bin/gcc -print-prog-name=f951`" > #> gdb -ex run -ex bt --batch --args $f951 fortran.dg/pr95090.f90 > > Program received signal SIGSEGV, Segmentation fault. > 0xf7aa5162 in __strlen_sse2_bsf () from /lib/libc.so.6 > #0 0xf7aa5162 in __strlen_sse2_bsf () from /lib/libc.so.6 > #1 0x083e7c3f in get_unique_hashed_string(char*, gfc_symbol*) () > #2 0x083e85a4 in gfc_find_derived_vtab(gfc_symbol*) () > #3 0x0847fde1 in resolve_fl_derived(gfc_symbol*) () > #4 0x0847c717 in resolve_symbol(gfc_symbol*) () > #5 0x084a78d0 in do_traverse_symtree(gfc_symtree*, void (*)(gfc_symtree*), void (*)(gfc_symbol*)) () > #6 0x08487f77 in resolve_types(gfc_namespace*) () > #7 0x0847b6e5 in gfc_resolve(gfc_namespace*) () > #8 0x0846e9f6 in gfc_parse_file() () > #9 0x084bebe7 in gfc_be_parse_file() () > #10 0x08a3b59e in compile_file() () > #11 0x083c98a5 in toplev::main(int, char**) () > #12 0x083cd9b1 in main () > > > So far so good, but there are no file locations shown, and I can't > switch frames and list code in GDB. > This although I built GCC with debug information and binaries are not stripped. > > I built GCC with > #> ../configure --enable-checking=yes,extra i686-linux > #> make BOOT_CFLAGS="-O2 -ggdb" bootstrap2-lean > > In desperation, I even tried > #> make BOOT_CFLAGS="-O2 -fanalyzer" bootstrap2-lean > and > #> make BOOT_CFLAGS="-O2 -fsanitize=address" bootstrap2-lean > but both compilation attempts failed. > > > Are there any magic knobs to make GDB output more useful? There's a whole wiki page about that: https://gcc.gnu.org/wiki/DebuggingGCC You probably don't want to use -O2
