Hello,
this patch addresses an issue uncovered by the undefined behavior
sanitizer. In function resolve_structure_cons in resolve.cc there is
a test starting with:
if (cons->expr->ts.type == BT_CHARACTER && comp->ts.u.cl
&& comp->ts.u.cl->length
&& comp->ts.u.cl->length->expr_type == EXPR_CONSTANT
and UBSAN complained of loads from comp->ts.u.cl->length->expr_type of
integer value 1818451807 which is outside of the value range expr_t
enum. If I understand the code correctly it the entire load was
unwanted because comp->ts.type in those cases is BT_CLASS and not
BT_CHARACTER. This patch simply adds a check to make sure it is only
accessed in those cases.
I have verified that the UPBSAN failure goes away with this patch, it
also passes bootstrap and testing on x86_64-linux. OK for master?
Thanks,
Martin
gcc/fortran/ChangeLog:
2023-08-14 Martin Jambor <mjam...@suse.cz>
PR fortran/110677
* resolve.cc (resolve_structure_cons): Check comp->ts is character
type before accessing stuff through comp->ts.u.cl.
---
gcc/fortran/resolve.cc | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/gcc/fortran/resolve.cc b/gcc/fortran/resolve.cc
index e7c8d919bef..5b4dfc5fcd2 100644
--- a/gcc/fortran/resolve.cc
+++ b/gcc/fortran/resolve.cc
@@ -1396,8 +1396,9 @@ resolve_structure_cons (gfc_expr *expr, int init)
the one of the structure, ensure this if the lengths are known at
compile time and when we are dealing with PARAMETER or structure
constructors. */
- if (cons->expr->ts.type == BT_CHARACTER && comp->ts.u.cl
- && comp->ts.u.cl->length
+ if (cons->expr->ts.type == BT_CHARACTER
+ && comp->ts.type == BT_CHARACTER
+ && comp->ts.u.cl && comp->ts.u.cl->length
&& comp->ts.u.cl->length->expr_type == EXPR_CONSTANT
&& cons->expr->ts.u.cl && cons->expr->ts.u.cl->length
&& cons->expr->ts.u.cl->length->expr_type == EXPR_CONSTANT
--
2.41.0
