Affects versions down to at least r5 : (missing attribute allocatable or pointer) $ cat z1.f90 program p type t end type type(t) :: x class(t) :: y print *, extends_type_of(x, y) end $ cat z2.f90 program p type t end type type(t) :: x class(t) :: y stop extends_type_of(x, y) end $ gfortran-13-20220626 -c z1.f90 z1.f90:5:16: 5 | class(t) :: y | 1 Error: CLASS variable 'y' at (1) must be dummy, allocatable or pointer (null):0: confused by earlier errors, bailing out $ gfortran-13-20220626 -c z2.f90 f951: internal compiler error: Segmentation fault 0xcd816f crash_signal ../../gcc/toplev.cc:322 0x78d799 gfc_simplify_extends_type_of(gfc_expr*, gfc_expr*) ../../gcc/fortran/simplify.cc:3109 0x70e0b6 do_simplify ../../gcc/fortran/intrinsic.cc:4670 0x718fca gfc_intrinsic_func_interface(gfc_expr*, int) ../../gcc/fortran/intrinsic.cc:5056 0x76db08 resolve_unknown_f ../../gcc/fortran/resolve.cc:2990 0x76db08 resolve_function ../../gcc/fortran/resolve.cc:3347 0x76db08 gfc_resolve_expr(gfc_expr*) ../../gcc/fortran/resolve.cc:7187 0x6fdfa4 gfc_reduce_init_expr(gfc_expr*) ../../gcc/fortran/expr.cc:3163 0x72b268 gfc_match_stopcode ../../gcc/fortran/match.cc:3157 0x751af1 match_word ../../gcc/fortran/parse.cc:67 0x75744d decode_statement ../../gcc/fortran/parse.cc:561 0x757a6a next_free ../../gcc/fortran/parse.cc:1397 0x757a6a next_statement ../../gcc/fortran/parse.cc:1629 0x758ffb parse_spec ../../gcc/fortran/parse.cc:4168 0x75c19c parse_progunit ../../gcc/fortran/parse.cc:6210 0x75d861 gfc_parse_file() ../../gcc/fortran/parse.cc:6755 0x7ab3ef gfc_be_parse_file ../../gcc/fortran/f95-lang.cc:229
$ cat z3.f90 program p type t integer :: a end type type(t) :: x class(t) :: y print *, extends_type_of(x, y) end $ cat z4.f90 program p type t integer :: a end type type(t) :: x class(t) :: y stop extends_type_of(x, y) end $ gfortran-13-20220626 -c z3.f90 z3.f90:6:16: 6 | class(t) :: y | 1 Error: CLASS variable 'y' at (1) must be dummy, allocatable or pointer $ gfortran-13-20220626 -c z4.f90 f951: internal compiler error: gfc_compare_derived_types: invalid derived type 0x73a249 gfc_report_diagnostic ../../gcc/fortran/error.cc:883 0x73bdc7 gfc_internal_error(char const*, ...) ../../gcc/fortran/error.cc:1503 0x748458 gfc_compare_derived_types(gfc_symbol*, gfc_symbol*) ../../gcc/fortran/interface.cc:619 0x7e032e gfc_type_is_extension_of(gfc_symbol*, gfc_symbol*) ../../gcc/fortran/symbol.cc:5116 0x7cfd01 gfc_simplify_extends_type_of(gfc_expr*, gfc_expr*) ../../gcc/fortran/simplify.cc:3109 0x750296 do_simplify ../../gcc/fortran/intrinsic.cc:4670 0x75b25a gfc_intrinsic_func_interface(gfc_expr*, int) ../../gcc/fortran/intrinsic.cc:5056 0x7b0068 resolve_unknown_f ../../gcc/fortran/resolve.cc:2990 0x7b0068 resolve_function ../../gcc/fortran/resolve.cc:3347 0x7b0068 gfc_resolve_expr(gfc_expr*) ../../gcc/fortran/resolve.cc:7187 0x740184 gfc_reduce_init_expr(gfc_expr*) ../../gcc/fortran/expr.cc:3163 0x76d538 gfc_match_stopcode ../../gcc/fortran/match.cc:3157 0x794051 match_word ../../gcc/fortran/parse.cc:67 0x7999ad decode_statement ../../gcc/fortran/parse.cc:561 0x799fca next_free ../../gcc/fortran/parse.cc:1397 0x799fca next_statement ../../gcc/fortran/parse.cc:1629 0x79b55b parse_spec ../../gcc/fortran/parse.cc:4168 0x79e6fc parse_progunit ../../gcc/fortran/parse.cc:6210 0x79fdc1 gfc_parse_file() ../../gcc/fortran/parse.cc:6755 0x7ee53f gfc_be_parse_file ../../gcc/fortran/f95-lang.cc:229
Infamous NULL pointer dereference. diff --git a/gcc/fortran/simplify.cc b/gcc/fortran/simplify.cc index c8f2ef9fbf4..1a33f26932a 100644 --- a/gcc/fortran/simplify.cc +++ b/gcc/fortran/simplify.cc @@ -3084,6 +3084,8 @@ is_last_ref_vtab (gfc_expr *e) gfc_expr * gfc_simplify_extends_type_of (gfc_expr *a, gfc_expr *mold) { + gfc_component *ac, *mc; + /* Avoid simplification of resolved symbols. */ if (is_last_ref_vtab (a) || is_last_ref_vtab (mold)) return NULL; @@ -3096,31 +3098,28 @@ gfc_simplify_extends_type_of (gfc_expr *a, gfc_expr *mold) if (UNLIMITED_POLY (a) || UNLIMITED_POLY (mold)) return NULL; + ac = a->ts.u.derived->components; + if (a->ts.type == BT_CLASS && !ac) + return NULL; + + mc = mold->ts.u.derived->components; + if (mold->ts.type == BT_CLASS && !mc) + return NULL; + /* Return .false. if the dynamic type can never be an extension. */ if ((a->ts.type == BT_CLASS && mold->ts.type == BT_CLASS - && !gfc_type_is_extension_of - (mold->ts.u.derived->components->ts.u.derived, - a->ts.u.derived->components->ts.u.derived) - && !gfc_type_is_extension_of - (a->ts.u.derived->components->ts.u.derived, - mold->ts.u.derived->components->ts.u.derived)) + && !gfc_type_is_extension_of (mc->ts.u.derived, ac->ts.u.derived) + && !gfc_type_is_extension_of (ac->ts.u.derived, mc->ts.u.derived)) || (a->ts.type == BT_DERIVED && mold->ts.type == BT_CLASS - && !gfc_type_is_extension_of - (mold->ts.u.derived->components->ts.u.derived, - a->ts.u.derived)) + && !gfc_type_is_extension_of (mc->ts.u.derived, a->ts.u.derived)) || (a->ts.type == BT_CLASS && mold->ts.type == BT_DERIVED - && !gfc_type_is_extension_of - (mold->ts.u.derived, - a->ts.u.derived->components->ts.u.derived) - && !gfc_type_is_extension_of - (a->ts.u.derived->components->ts.u.derived, - mold->ts.u.derived))) + && !gfc_type_is_extension_of (mold->ts.u.derived, ac->ts.u.derived) + && !gfc_type_is_extension_of (ac->ts.u.derived, mold->ts.u.derived))) return gfc_get_logical_expr (gfc_default_logical_kind, &a->where, false); /* Return .true. if the dynamic type is guaranteed to be an extension. */ if (a->ts.type == BT_CLASS && mold->ts.type == BT_DERIVED - && gfc_type_is_extension_of (mold->ts.u.derived, - a->ts.u.derived->components->ts.u.derived)) + && gfc_type_is_extension_of (mold->ts.u.derived, ac->ts.u.derived)) return gfc_get_logical_expr (gfc_default_logical_kind, &a->where, true); return NULL;
(In reply to kargl from comment #2) > Infamous NULL pointer dereference. Yes. Shorter fix: diff --git a/gcc/fortran/simplify.cc b/gcc/fortran/simplify.cc index e8e3ec63669..b5112da441a 100644 --- a/gcc/fortran/simplify.cc +++ b/gcc/fortran/simplify.cc @@ -3096,6 +3096,10 @@ gfc_simplify_extends_type_of (gfc_expr *a, gfc_expr *mold) if (UNLIMITED_POLY (a) || UNLIMITED_POLY (mold)) return NULL; + if ((a->ts.type == BT_CLASS && !gfc_expr_attr (a).class_ok) + || (mold->ts.type == BT_CLASS && !gfc_expr_attr (mold).class_ok)) + return NULL; + /* Return .false. if the dynamic type can never be an extension. */ if ((a->ts.type == BT_CLASS && mold->ts.type == BT_CLASS && !gfc_type_is_extension_of I think we need a good (better) set of macros to concisely handle problems like the above to improve error recovery.
On Tue, Jun 28, 2022 at 07:43:39PM +0000, anlauf at gcc dot gnu.org wrote: > (In reply to kargl from comment #2) > > Infamous NULL pointer dereference. > > Yes. > > Shorter fix: > > diff --git a/gcc/fortran/simplify.cc b/gcc/fortran/simplify.cc > index e8e3ec63669..b5112da441a 100644 > --- a/gcc/fortran/simplify.cc > +++ b/gcc/fortran/simplify.cc > @@ -3096,6 +3096,10 @@ gfc_simplify_extends_type_of (gfc_expr *a, gfc_expr > *mold) > if (UNLIMITED_POLY (a) || UNLIMITED_POLY (mold)) > return NULL; > > + if ((a->ts.type == BT_CLASS && !gfc_expr_attr (a).class_ok) > + || (mold->ts.type == BT_CLASS && !gfc_expr_attr (mold).class_ok)) > + return NULL; > + > /* Return .false. if the dynamic type can never be an extension. */ > if ((a->ts.type == BT_CLASS && mold->ts.type == BT_CLASS > && !gfc_type_is_extension_of > Shorter is definitely better. One thing that my patch allowed was shortening the tortured if-statement that is spread across a dozen of so lines. In any event, if you're patch survives regression testing, ok to commit.
(In reply to Steve Kargl from comment #4) > Shorter is definitely better. One thing that my patch > allowed was shortening the tortured if-statement that > is spread across a dozen of so lines. In any event, > if you're patch survives regression testing, ok to > commit. It did regtest fine. I nevertheless submitted here https://gcc.gnu.org/pipermail/fortran/2022-June/057966.html and will wait for 24h for comments.
The master branch has been updated by Harald Anlauf <anlauf@gcc.gnu.org>: https://gcc.gnu.org/g:b8f284d3673004dffae714b56ed663467c2a52a7 commit r13-1349-gb8f284d3673004dffae714b56ed663467c2a52a7 Author: Harald Anlauf <anlauf@gmx.de> Date: Tue Jun 28 22:29:28 2022 +0200 Fortran: improve error recovery for EXTENDS_TYPE_OF() [PR106121] gcc/fortran/ChangeLog: PR fortran/106121 * simplify.cc (gfc_simplify_extends_type_of): Do not attempt to simplify when one of the arguments is a CLASS variable that was not properly declared. gcc/testsuite/ChangeLog: PR fortran/106121 * gfortran.dg/extends_type_of_4.f90: New test. Co-authored-by: Steven G. Kargl <kargl@gcc.gnu.org>
Fixed for gcc-13. Thanks for the report!
The releases/gcc-12 branch has been updated by Harald Anlauf <anlauf@gcc.gnu.org>: https://gcc.gnu.org/g:cf12a703cf7af34d91a6346883600caac2156e6e commit r12-8543-gcf12a703cf7af34d91a6346883600caac2156e6e Author: Harald Anlauf <anlauf@gmx.de> Date: Tue Jun 28 22:29:28 2022 +0200 Fortran: improve error recovery for EXTENDS_TYPE_OF() [PR106121] gcc/fortran/ChangeLog: PR fortran/106121 * simplify.cc (gfc_simplify_extends_type_of): Do not attempt to simplify when one of the arguments is a CLASS variable that was not properly declared. gcc/testsuite/ChangeLog: PR fortran/106121 * gfortran.dg/extends_type_of_4.f90: New test. Co-authored-by: Steven G. Kargl <kargl@gcc.gnu.org> (cherry picked from commit b8f284d3673004dffae714b56ed663467c2a52a7)
The releases/gcc-11 branch has been updated by Harald Anlauf <anlauf@gcc.gnu.org>: https://gcc.gnu.org/g:19f6e8ddfc447ac3b6198ab4b0176323e75a65cc commit r11-10106-g19f6e8ddfc447ac3b6198ab4b0176323e75a65cc Author: Harald Anlauf <anlauf@gmx.de> Date: Tue Jun 28 22:29:28 2022 +0200 Fortran: improve error recovery for EXTENDS_TYPE_OF() [PR106121] gcc/fortran/ChangeLog: PR fortran/106121 * simplify.c (gfc_simplify_extends_type_of): Do not attempt to simplify when one of the arguments is a CLASS variable that was not properly declared. gcc/testsuite/ChangeLog: PR fortran/106121 * gfortran.dg/extends_type_of_4.f90: New test. Co-authored-by: Steven G. Kargl <kargl@gcc.gnu.org> (cherry picked from commit b8f284d3673004dffae714b56ed663467c2a52a7)
The releases/gcc-10 branch has been updated by Harald Anlauf <anlauf@gcc.gnu.org>: https://gcc.gnu.org/g:8bb7567f5a3e67ab91614d4538eb3a14a5a76274 commit r10-10881-g8bb7567f5a3e67ab91614d4538eb3a14a5a76274 Author: Harald Anlauf <anlauf@gmx.de> Date: Tue Jun 28 22:29:28 2022 +0200 Fortran: improve error recovery for EXTENDS_TYPE_OF() [PR106121] gcc/fortran/ChangeLog: PR fortran/106121 * simplify.c (gfc_simplify_extends_type_of): Do not attempt to simplify when one of the arguments is a CLASS variable that was not properly declared. gcc/testsuite/ChangeLog: PR fortran/106121 * gfortran.dg/extends_type_of_4.f90: New test. Co-authored-by: Steven G. Kargl <kargl@gcc.gnu.org> (cherry picked from commit b8f284d3673004dffae714b56ed663467c2a52a7)