Hello.
As reported in mentioned PR, we segfault in gcov tool when one uses -a. It's
caused by fact
that vectors blocks and block_lists have indices kept in sync and as one
removes an element
from blocks via:
blocked.erase (it);
Then calling recursively the same function breaks the synchronization. The
patch was originally
written by Joshua (adding him to CC). If I'm correct calling:
- unblock (u, blocked, block_lists);
does not make sense as we've already removed 'u'. Plus one needs to put content
of block_lists[index]
to a separate vector in order to not to break iteration.
Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
And fixed the problem reported in opensuse bugzilla (mentioned in the GCC
bugzilla PR).
Ready to be installed?
Martin
gcc/ChangeLog:
2017-07-26 Martin Liska <mli...@suse.cz>
PR gcov-profile/81561
* gcov.c (unblock): Make unblocking safe as we need to preserve
index correspondence of blocks and block_lists.
---
gcc/gcov.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
>From a31295c91c57fd3338e47eba1f513fcb1c37d8d2 Mon Sep 17 00:00:00 2001
From: marxin <mli...@suse.cz>
Date: Wed, 26 Jul 2017 14:21:52 +0200
Subject: [PATCH] Fix segfault in gcov.c (PR gcov-profile/81561).
gcc/ChangeLog:
2017-07-26 Martin Liska <mli...@suse.cz>
PR gcov-profile/81561
* gcov.c (unblock): Make unblocking safe as we need to preserve
index correspondence of blocks and block_lists.
---
gcc/gcov.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/gcc/gcov.c b/gcc/gcov.c
index e324cadad82..c56bac20278 100644
--- a/gcc/gcov.c
+++ b/gcc/gcov.c
@@ -539,13 +539,13 @@ unblock (const block_t *u, block_vector_t &blocked,
unsigned index = it - blocked.begin ();
blocked.erase (it);
- for (block_vector_t::iterator it2 = block_lists[index].begin ();
- it2 != block_lists[index].end (); it2++)
- unblock (*it2, blocked, block_lists);
- for (unsigned j = 0; j < block_lists[index].size (); j++)
- unblock (u, blocked, block_lists);
+ block_vector_t to_unblock (block_lists[index]);
block_lists.erase (block_lists.begin () + index);
+
+ for (block_vector_t::iterator it = to_unblock.begin ();
+ it != to_unblock.end (); it++)
+ unblock (*it, blocked, block_lists);
}
/* Find circuit going to block V, PATH is provisional seen cycle.
--
2.13.3
