On Tue, 9 Apr 2024, Jørgen Kvalsvik wrote:
> PR114601 shows that it is possible to reach the condition_uid lookup
> without having also created the fn->cond_uids, through
> compiler-generated conditionals. Consider all lookups on non-existing
> maps misses, which they are from the perspective of the source code, to
> avoid the NULL access.
OK.
> PR gcov-profile/114601
>
> gcc/ChangeLog:
>
> * tree-profile.cc (condition_uid): Guard fn->cond_uids access.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.misc-tests/gcov-pr114601.c: New test.
> ---
> gcc/testsuite/gcc.misc-tests/gcov-pr114601.c | 11 +++++++++++
> gcc/tree-profile.cc | 9 +++++++--
> 2 files changed, 18 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.misc-tests/gcov-pr114601.c
>
> diff --git a/gcc/testsuite/gcc.misc-tests/gcov-pr114601.c
> b/gcc/testsuite/gcc.misc-tests/gcov-pr114601.c
> new file mode 100644
> index 00000000000..72248c8fd25
> --- /dev/null
> +++ b/gcc/testsuite/gcc.misc-tests/gcov-pr114601.c
> @@ -0,0 +1,11 @@
> +/* PR gcov-profile/114601 */
> +/* { dg-do compile } */
> +/* { dg-options "-fcondition-coverage -finstrument-functions-once" } */
> +
> +/* -finstrument-functions-once inserts a hidden conditional expression into
> + this function which otherwise has none. This caused a crash on looking up
> + the condition as the cond->expr map is not created unless it necessary.
> */
> +void
> +empty (void)
> +{
> +}
> diff --git a/gcc/tree-profile.cc b/gcc/tree-profile.cc
> index b85111624fe..b87c121790c 100644
> --- a/gcc/tree-profile.cc
> +++ b/gcc/tree-profile.cc
> @@ -359,12 +359,17 @@ condition_index (unsigned flag)
> min-max, etc., which leaves ghost identifiers in basic blocks that do not
> end with a conditional jump. They are not really meaningful for condition
> coverage anymore, but since coverage is unreliable under optimization
> anyway
> - this is not a big problem. */
> + this is not a big problem.
> +
> + The cond_uids map in FN cannot be expected to exist. It will only be
> + created if it is needed, and a function may have gconds even though there
> + are none in source. This can be seen in PR gcov-profile/114601, when
> + -finstrument-functions-once is used and the function has no conditions.
> */
> unsigned
> condition_uid (struct function *fn, basic_block b)
> {
> gimple *stmt = gsi_stmt (gsi_last_bb (b));
> - if (!safe_is_a<gcond *> (stmt))
> + if (!safe_is_a <gcond*> (stmt) || !fn->cond_uids)
> return 0;
>
> unsigned *v = fn->cond_uids->get (as_a <gcond*> (stmt));
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
