On 09/04/2024 13:43, 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.
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.
I tested this with Zdenek's configuration on x86_64/linux, but I would
mostly consider it obvious (with the test case).
Thanks for the report, Zdenek.
---
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));
