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From: "vultkayn at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug analyzer/109365] Double delete yields -Wanalyzer-use-after-free instead of -Wanalyzer-double-free
Date: Wed, 05 Jul 2023 11:31:41 +0000	[thread overview]
Message-ID: <bug-109365-4-XIipBLrN24@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-109365-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109365

Benjamin Priour <vultkayn at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |vultkayn at gcc dot gnu.org

--- Comment #3 from Benjamin Priour <vultkayn at gcc dot gnu.org> ---
Changing the second delete expression into a direct call to "operator delete"
results in the correct warning Wanalyzer-double-free being emitted.

This is due to delete expression first calling the destructor and performing
extra operations, whose one of them is a dereference.

"delete expression" compiled with -O0 results on my x86_64-linux-gnu
to analyzer ipa:

  if (a.0_11 != 0B)
    goto <bb 3>; [INV]
  else
    goto <bb 4>; [INV]

  <bb 3> :
  *a.0_11 ={v} {CLOBBER};
  operator delete (a.0_11, 8);

  <bb 4> :
  _14 = 0;

Entry statement of bb3 is the one actually detected as -Wanalyzer-double-free.

  parent reply	other threads:[~2023-07-05 11:31 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-31 20:31 [Bug analyzer/109365] New: " priour.be at gmail dot com
2023-03-31 20:34 ` [Bug analyzer/109365] " dmalcolm at gcc dot gnu.org
2023-03-31 20:37 ` priour.be at gmail dot com
2023-07-05 11:31 ` vultkayn at gcc dot gnu.org [this message]
2023-07-07 11:28 ` vultkayn at gcc dot gnu.org
2023-07-21 22:22 ` dmalcolm at gcc dot gnu.org
2023-07-26 17:10 ` vultkayn at gcc dot gnu.org

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