From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 88540385DC2B; Wed, 1 Apr 2020 17:17:34 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 88540385DC2B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1585761454; bh=Km2o4W6qT6XSgRVcnyzONby0gDVPBC6ufFRVdoqsPl8=; h=From:To:Subject:Date:In-Reply-To:References:From; b=OqlxkIykv37wRX4aREMM7FP2Jw67MyN3UEW67gztToj+JTDMmXq/wdnu4Vc/6uQrE 5fRa/lJlDWXfGnbLdJ/3nVAq5RByPj/9HhyzLRml+5XZG+6VZLUjpJj199SdfOjubN y8HGZ6mEq888dxOZvpYMb3GPNQS4oVVbQhC+4o9M= From: "felix-gcc at fefe dot de" To: gcc-bugs@gcc.gnu.org Subject: [Bug c/94444] __attribute__((access(...))) ignored for memcpy when compiling with -Os Date: Wed, 01 Apr 2020 17:17:34 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c X-Bugzilla-Version: unknown X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: felix-gcc at fefe dot de X-Bugzilla-Status: WAITING X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 01 Apr 2020 17:17:34 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94444 --- Comment #4 from felix-gcc at fefe dot de --- Sure, here's a test case: #include __attribute__((access(read_only,2,3), access(write_only,1,3))) extern void* memcpy(void* dest, const void* src, size_t len); int main() { char buf[10]; memcpy(buf,"fnordfnord",11); // should reject or at least warn } $ gcc -c t.c t.c: In function =E2=80=98main=E2=80=99: t.c:8:3: warning: =E2=80=98memcpy=E2=80=99 writing 11 bytes into a region o= f size 10 overflows the destination [-Wstringop-overflow=3D] 8 | memcpy(buf,"fnordfnord",11); // should reject or at least warn | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ t.c:4:14: note: in a call to function =E2=80=98memcpy=E2=80=99 declared wit= h attribute =E2=80=98write_only (1, 3)=E2=80=99 4 | extern void* memcpy(void* dest, const void* src, size_t len); | ^~~~~~ $ gcc -c t.c -Os $ gcc -v [...] gcc version 10.0.1 20200401 (experimental) (GCC)=