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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug gcov-profile/97461] [11 Regression] allocate_gcov_kvp()
 deadlocks in firefox LTO+PGO build (overridden malloc() recursion)
Date: Mon, 19 Oct 2020 07:15:27 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97461

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Hmm, is the TOPN allocation strathegy configurable?  I wonder whether we ha=
ve
to resort to an alternate allocation scheme (mmap/sbrk), avoiding libc?  At
least
I don't see a good way to force the gcov allocation to call the libc malloc
rather than a user replacement that is being instrumented.  Of course the
instrumentation code could do sth like

  if (is_allocated =3D=3D 0)
    {
      is_allocated =3D in_progress;
      ... =3D malloc ();
      is_allocated =3D 1;
    }
  else if (is_allocted =3D=3D in_progress)
    {
      topn_mem =3D &transitional_garbage_space;
    }

but of course that's quite some overhead for a small benefit.  Maybe it
could be hidden in gcov_malloc.=