https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54924
--- Comment #6 from Martin Sebor <msebor at gcc dot gnu.org> ---
As a heads up, with the patch for bug 79234 applied and with -Wsystem-headers
explicitly specified GCC issues the warnings below (the -Warray-bounds is
printed even without the patch). Unfortunately, with the default
-Wno-system-headers, warnings from std::string and the rest of libstdc++
headers are suppressed.
$ cat t.C && /build/gcc-79234/gcc/xg++ -B /build/gcc-79234/gcc -nostdinc++ -I
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu
-I /build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include -I
/src/gcc/79234/libstdc++-v3/libsupc++ -I
/src/gcc/79234/libstdc++-v3/include/backward -I
/src/gcc/79234/libstdc++-v3/testsuite/util -L
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/src/.libs -O2 -S -Wall
-Wsystem-headers t.C
#include <string>
std::string s ("abc", 5);
In file included from
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/stl_algobase.h:66:0,
from
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/char_traits.h:39,
from
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include/string:40,
from t.C:1:
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/stl_iterator_base_funcs.h:
In function ‘(static initializers for t.C)’:
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/stl_iterator_base_funcs.h:104:21:
warning: array subscript is above array bounds [-Warray-bounds]
return __last - __first;
~~~~~~~^~~~~~~~~
In file included from
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include/string:40:0,
from t.C:1:
In static member function ‘static std::char_traits<char>::char_type*
std::char_traits<char>::copy(std::char_traits<char>::char_type*, const
char_type*, std::size_t)’,
inlined from ‘static void std::__cxx11::basic_string<_CharT, _Traits,
_Alloc>::_S_copy(_CharT*, const _CharT*, std::__cxx11::basic_string<_CharT,
_Traits, _Alloc>::size_type) [with _CharT = char; _Traits =
std::char_traits<char>; _Alloc = std::allocator<char>]’ at
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_string.h:324:21,
inlined from ‘void std::__cxx11::basic_string<_CharT, _Traits,
_Alloc>::_M_construct(_InIterator, _InIterator, std::forward_iterator_tag)
[with _FwdIterator = const char*; _CharT = char; _Traits =
std::char_traits<char>; _Alloc = std::allocator<char>]’,
inlined from ‘void std::__cxx11::basic_string<_CharT, _Traits,
_Alloc>::_M_construct(_InIterator, _InIterator) [with _InIterator = const
char*; _CharT = char; _Traits = std::char_traits<char>; _Alloc =
std::allocator<char>]’ at
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_string.h:220:23,
inlined from ‘std::__cxx11::basic_string<_CharT, _Traits,
_Alloc>::basic_string(const _CharT*, std::__cxx11::basic_string<_CharT,
_Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits =
std::char_traits<char>; _Alloc = std::allocator<char>]’ at
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_string.h:486:21,
inlined from ‘void __static_initialization_and_destruction_0(int, int)’ at
t.C:3:24,
inlined from ‘(static initializers for t.C)’ at t.C:3:25:
/build/gcc-79234/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/char_traits.h:292:66:
warning: ‘void* __builtin_memcpy(void*, const void*, long unsigned int)’
reading 5 bytes from a region of size 4 [-Wstringop-overflow=]
return static_cast<char_type*>(__builtin_memcpy(__s1, __s2, __n));
^
