Dear all,
the code in the PR demonstrates that dependency checking in the
frontend optimization was not recovering well from invalid code,
leading to a NULL pointer dereference. An easy and really obvious
fix.
Regtested on x86_64-pc-linux-gnu. OK for mainline?
Thanks,
Harald
From d27e1b13ba312411ce271f5122f694ffe6c051e6 Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anl...@gmx.de>
Date: Mon, 23 Jan 2023 22:13:44 +0100
Subject: [PATCH] Fortran: fix NULL pointer dereference in gfc_check_dependency
[PR108502]
gcc/fortran/ChangeLog:
PR fortran/108502
* dependency.cc (gfc_check_dependency): Prevent NULL pointer
dereference while recursively checking expressions.
gcc/testsuite/ChangeLog:
PR fortran/108502
* gfortran.dg/pr108502.f90: New test.
---
gcc/fortran/dependency.cc | 5 +++++
gcc/testsuite/gfortran.dg/pr108502.f90 | 12 ++++++++++++
2 files changed, 17 insertions(+)
create mode 100644 gcc/testsuite/gfortran.dg/pr108502.f90
diff --git a/gcc/fortran/dependency.cc b/gcc/fortran/dependency.cc
index 43417a6ec76..9117825ee6e 100644
--- a/gcc/fortran/dependency.cc
+++ b/gcc/fortran/dependency.cc
@@ -1292,6 +1292,11 @@ gfc_check_dependency (gfc_expr *expr1, gfc_expr *expr2, bool identical)
if (expr1->expr_type != EXPR_VARIABLE)
gfc_internal_error ("gfc_check_dependency: expecting an EXPR_VARIABLE");
+ /* Prevent NULL pointer dereference while recursively analyzing invalid
+ expressions. */
+ if (expr2 == NULL)
+ return 0;
+
switch (expr2->expr_type)
{
case EXPR_OP:
diff --git a/gcc/testsuite/gfortran.dg/pr108502.f90 b/gcc/testsuite/gfortran.dg/pr108502.f90
new file mode 100644
index 00000000000..45f73849c57
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr108502.f90
@@ -0,0 +1,12 @@
+! { dg-do compile }
+! { dg-options "-O2 -ffrontend-optimize" }
+! PR fortran/108502 - ICE in gfc_check_dependency
+! Contributed by G.Steinmetz
+
+integer function n()
+ integer :: a(1)
+ a = [1] / 0
+end
+program p
+ integer :: b = n() ! { dg-error "must be an intrinsic function" }
+end
--
2.35.3
