[Bug fortran/103507] New: ICE in resolve_block_construct, at fortran/resolve.c:10787

[Bug fortran/103507] New: ICE in resolve_block_construct, at fortran/resolve.c:10787

[gscfq@t-online.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103507

            Bug ID: 103507
           Summary: ICE in resolve_block_construct, at
                    fortran/resolve.c:10787
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gscfq@t-online.de
  Target Milestone: ---

Seems to have started with r6 :


$ cat z1.f90
subroutine s
block
end if
end
program p
end


$ cat z2.f90
subroutine s
block
end do
end
program p
end


$ cat z4.f90
subroutine s(x)
block
end if
end
end


$ cat z5.f90
subroutine s(x)
block
end subroutine
end
end


$ gfortran-12-20211128 -c z1.f90
z1.f90:3:3:

    3 | end if
      |   1
Error: Expecting END BLOCK statement at (1)
z1.f90:5:9:

    5 | program p
      |         1
Error: Unexpected PROGRAM statement at (1)
f951: internal compiler error: Segmentation fault
0xf0942f crash_signal
        ../../gcc/toplev.c:322
0x853098 gfc_resolve(gfc_namespace*)
        ../../gcc/fortran/resolve.c:17556
0x853098 resolve_block_construct
        ../../gcc/fortran/resolve.c:10787
0x853098 gfc_resolve_code(gfc_code*, gfc_namespace*)
        ../../gcc/fortran/resolve.c:12182
0x854f97 resolve_codes
        ../../gcc/fortran/resolve.c:17536
0x85505e gfc_resolve(gfc_namespace*)
        ../../gcc/fortran/resolve.c:17571
0x83d314 resolve_all_program_units
        ../../gcc/fortran/parse.c:6573
0x83d314 gfc_parse_file()
        ../../gcc/fortran/parse.c:6829
0x88b37f gfc_be_parse_file
        ../../gcc/fortran/f95-lang.c:216

[Bug fortran/103507] ICE in resolve_block_construct, at fortran/resolve.c:10787

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103507

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2021-12-01
     Ever confirmed|0                           |1
                 CC|                            |marxin at gcc dot gnu.org

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
All compilers I have do ICE (4.8.0+).

[Bug fortran/103507] ICE in resolve_block_construct, at fortran/resolve.c:10787

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103507

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kargl at gcc dot gnu.org

--- Comment #2 from kargl at gcc dot gnu.org ---
This patch prevents the ICE, but is not as elegant as I would like.

diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index f074a0ab3a1..08f657407da 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -17553,6 +17553,14 @@ gfc_resolve (gfc_namespace *ns)
   code_stack *old_cs_base;
   struct gfc_omp_saved_state old_omp_state;

+  if (!ns)
+    {
+      int ecnt;
+      gfc_get_errors (NULL, &ecnt);
+      if (ecnt > 0)
+       gfc_fatal_error ("Namespace corruption due to previous errors");
+    }
+
   if (ns->resolved)
     return;

The problem seems to be with one of more namespaces being
incomplete and/or overlapping.