From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id BD86A3858D39; Wed, 15 Dec 2021 17:58:25 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org BD86A3858D39 From: "msebor at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/54924] Warn for std::string constructor with wrong size Date: Wed, 15 Dec 2021 17:58:25 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: libstdc++ X-Bugzilla-Version: 4.7.2 X-Bugzilla-Keywords: diagnostic X-Bugzilla-Severity: enhancement X-Bugzilla-Who: msebor at gcc dot gnu.org X-Bugzilla-Status: RESOLVED X-Bugzilla-Resolution: FIXED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: msebor at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: resolution bug_status 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, 15 Dec 2021 17:58:25 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D54924 Martin Sebor changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |FIXED Status|ASSIGNED |RESOLVED --- Comment #15 from Martin Sebor --- GCC 11 and 12 finally diagnose this problem even without -Wsystem-headers, albeit inconsistently. At -O1 GCC 11 issues -Wstringop-overread: In file included from /build/gcc-11-branch/x86_64-pc-linux-gnu/libstdc++-v3/include/string:40, from pr54924.C:2: In static member function =E2=80=98static std::char_traits::char_type* std::char_traits::copy(std::char_traits::char_type*, const char_type*, std::size_t)=E2=80=99, inlined from =E2=80=98static void std::__cxx11::basic_string<_CharT, _T= raits, _Alloc>::_S_copy(_CharT*, const _CharT*, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type) [with _CharT =3D char; _Traits =3D std::char_traits; _Alloc =3D std::allocator]=E2=80=99 at /build/gcc-11-branch/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_st= ring.h:359:21, inlined from =E2=80=98static void std::__cxx11::basic_string<_CharT, _T= raits, _Alloc>::_S_copy_chars(_CharT*, const _CharT*, const _CharT*) [with _CharT = =3D char; _Traits =3D std::char_traits; _Alloc =3D std::allocator]= =E2=80=99 at /build/gcc-11-branch/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_st= ring.h:406:16, inlined from =E2=80=98void std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_M_construct(_InIterator, _InIterator, std::forward_iterator_tag) [with _FwdIterator =3D const char*; _CharT =3D char; _Traits =3D std::char_traits; _Alloc =3D std::allocator]=E2=80=99 at /build/gcc-11-branch/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_st= ring.tcc:225:25, inlined from =E2=80=98void std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_M_construct_aux(_InIterator, _InIterator, std::__false_type) [with _InIterator =3D const char*; _CharT =3D char; _Traits =3D std::char_traits<= char>; _Alloc =3D std::allocator]=E2=80=99 at /build/gcc-11-branch/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_st= ring.h:255:23, inlined from =E2=80=98void std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_M_construct(_InIterator, _InIterator) [with _InIterator =3D const char*; _CharT =3D char; _Traits =3D std::char_traits; _Alloc =3D std::allocator]=E2=80=99 at /build/gcc-11-branch/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_st= ring.h:274:20, inlined from =E2=80=98std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT =3D char; _Traits = =3D std::char_traits; _Alloc =3D std::allocator]=E2=80=99 at /build/gcc-11-branch/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_st= ring.h:521:21, inlined from =E2=80=98void __static_initialization_and_destruction_0(in= t, int)=E2=80=99 at pr54924.C:4:24, inlined from =E2=80=98(static initializers for pr54924.C)=E2=80=99 at p= r54924.C:4:25: /build/gcc-11-branch/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/char_tra= its.h:409:56: warning: =E2=80=98void* __builtin_memcpy(void*, const void*, long unsigned = int)=E2=80=99 reading 5 bytes from a region of size 4 [-Wstringop-overread] 409 | return static_cast(__builtin_memcpy(__s1, __s2, __n)); |=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20= =20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20 ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~ As a result of g:b8f2efaed02e8b03d215d74e42d3707761772f64 GCC 12 doesn't is= sue -Wstringop-overread at any level but at -O2 it does issue -Warray-bounds: In file included from /build/gcc-master/x86_64-pc-linux-gnu/libstdc++-v3/include/string:53, from pr54924.C:2: In constructor =E2=80=98std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, size_type, const _Alloc&) [with _CharT= =3D char; _Traits =3D std::char_traits; _Alloc =3D std::allocator]= =E2=80=99, inlined from =E2=80=98void __static_initialization_and_destruction_0(in= t, int)=E2=80=99 at pr54924.C:4:24, inlined from =E2=80=98(static initializers for pr54924.C)=E2=80=99 at p= r54924.C:4:25: /build/gcc-master/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_strin= g.h:620:21: warning: array subscript 5 is outside array bounds of =E2=80=98const char [= 4]=E2=80=99 [-Warray-bounds] 620 | _M_construct(__s, __s + __n, std::forward_iterator_tag()); | ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I'm not happy with how this has turned out but I'm also not sure how to imp= rove things, so I'll resolve this as fixed.=