[PATCH] Clean up dangling pointers in cgraph_edge (PR ipa/89330).

[Martin Liška]

Hi.

We have to clean up dangling pointers before we call ggc_free for a cgraph_edge.

Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
And it survives --enable-checking=release bootstrap on x86_64-linux-gnu.

Ready to be installed?
Thanks,
Martin

gcc/ChangeLog:

2019-07-30  Martin Liska  <mli...@suse.cz>

        PR ipa/89330
        * cgraph.c (symbol_table::free_edge): Memset 0 to cgraph_edge
        before we call ggc_free.
---
 gcc/cgraph.c | 2 ++
 1 file changed, 2 insertions(+)



diff --git a/gcc/cgraph.c b/gcc/cgraph.c
index 81250acb70c..372974f12df 100644
--- a/gcc/cgraph.c
+++ b/gcc/cgraph.c
@@ -1008,6 +1008,8 @@ symbol_table::free_edge (cgraph_edge *e)
   if (e->m_summary_id != -1)
     edge_released_summary_ids.safe_push (e->m_summary_id);
 
+  /* Clear out the edge so we do not dangle pointers.  */
+  memset (e, 0, sizeof (*e));
   if (e->indirect_info)
     ggc_free (e->indirect_info);
   ggc_free (e);