[Bug gcov-profile/80911] gcov failed: gcno corrupted

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80911

--- Comment #11 from Martin Liška <marxin at gcc dot gnu.org> ---
Ok, I'm probably starting to know what's wrong. Can you please following patch
and provide me output:

diff --git a/gcc/gcov.c b/gcc/gcov.c
index a5aa4aadcac..b0417165642 100644
--- a/gcc/gcov.c
+++ b/gcc/gcov.c
@@ -1382,12 +1382,15 @@ read_graph_file (void)
       else if (fn && tag == GCOV_TAG_ARCS)
        {
          unsigned src = gcov_read_unsigned ();
+         fprintf (stderr, "arc: %d\n", src);
          fn->blocks[src].id = src;
          unsigned num_dests = GCOV_TAG_ARCS_NUM (length);
          block_t *src_blk = &fn->blocks[src];
          unsigned mark_catches = 0;
          struct arc_info *arc;

+         fprintf (stderr, "fn->blocks.size(): %d, succ: %p\n",
+                  fn->blocks.size (), fn->blocks[src].succ);
          if (src >= fn->blocks.size () || fn->blocks[src].succ)
            goto corrupt;

@@ -1395,6 +1398,8 @@ read_graph_file (void)
            {
              unsigned dest = gcov_read_unsigned ();
              unsigned flags = gcov_read_unsigned ();
+             fprintf (stderr, "dest: %d\n", dest);
+             fprintf (stderr, "flags: %d\n", flags);

              if (dest >= fn->blocks.size ())
                goto corrupt;

As block_t does not have a default ctor, blocks.resize() adds new elements that
are not cleared. I'm going to prepare a patch.