[Bug c++/107532] [13 Regression] -Werror=dangling-reference false positives in libcamera-0.0.1
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107532
--- Comment #20 from Rolf Eike Beer ---
I'm running this rev:
g++-13 (Gentoo 13.0.1. p, commit 27495bc8fe028d4a68e97ad12b52231772e48dcf)
13.0.1 20230308 (experimental)
And I still get a warning for this testcase:
// $ cat ref.cpp
#include
const std::string &trigger(const std::string &server);
int verifyDevXml()
{
const auto &str = trigger("");
if (str.empty())
return 1;
return 0;
}
// $ g++-13 -Wdangling-reference -c -o ref.o ref.cpp
ref.cpp: In function ?int verifyDevXml()?:
ref.cpp:7:15: warning: possibly dangling reference to a temporary
[-Wdangling-reference]
7 | const auto &str = trigger("");
| ^~~
ref.cpp:7:28: note: the temporary was destroyed at the end of the full
expression ?trigger(std::__cxx11::basic_string(((const char*)""),
std::allocator()))?
7 | const auto &str = trigger("");
| ~~~^~~~
The problem is to my understanding that this warns about the temporary
constructed in the argument, i.e. it warns that the std::string() formed from
"" could be bound here. Which could be true if the function does that, but in
my case it is just used as a lookup for a map and not returned.
[Bug c++/104012] New: -Wformat-truncation warnings not taking previous length check into account
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104012
Bug ID: 104012
Summary: -Wformat-truncation warnings not taking previous
length check into account
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: e...@sf-mail.de
Target Milestone: ---
This code is from CMake's Source/cmLocalUnixMakefileGenerator3.cxx:
std::string cmLocalUnixMakefileGenerator3::CreateMakeVariable(
std::string const& s, std::string const& s2)
{
[…]
char buffer[5];
int ni = 0;
snprintf(buffer, sizeof(buffer), "%04d", ni);
ret = str1 + str2 + buffer;
while (this->ShortMakeVariableMap.count(ret) && ni < 1000) {
++ni;
snprintf(buffer, sizeof(buffer), "%04d", ni);
ret = str1 + str2 + buffer;
}
The second snprintf() causes this warning:
…/CMake/Source/cmLocalUnixMakefileGenerator3.cxx:1311:41: warning: '%04d'
directive output may be truncated writing between 4 and 11 bytes into a region
of size 5 [-Wformat-truncation=]
1311 | snprintf(buffer, sizeof(buffer), "%04d", ni);
| ^~~~
…/CMake/Source/cmLocalUnixMakefileGenerator3.cxx:1311:40: note: directive
argument in the range [-2147483647, 2147483647]
1311 | snprintf(buffer, sizeof(buffer), "%04d", ni);
|^~
The second warning line shows that the argument range is not correctly limited
to [0, 1000], which would have avoided the warning. A similar warning is shown
~30 lines earlier in the same file for basically the same code.
My current version is:
gcc-12.0.0 (Gentoo 12.0.0_pre p2, commit
8b35f02ed599a70cce752e3cb544a7c9f808fce8) 12.0.0 20220111 (experimental)
The version used previously has been built on 2021-08-14T20:47:39 and didn't
show that warning.
[Bug tree-optimization/104012] [12 regression] -Wformat-truncation warnings not taking previous length check into account
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104012 --- Comment #2 from Rolf Eike Beer --- Created attachment 52182 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52182&action=edit preprocessed source
[Bug tree-optimization/104012] [12 regression] -Wformat-truncation warnings not taking previous length check into account
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104012 --- Comment #4 from Rolf Eike Beer --- I have rebuilt gcc today, now at commit b77e3b4e4589e56c01511fabdbaadb029cd47f5c. Configuration line: /var/tmp/portage/sys-devel/gcc-12.0.0_pre/work/gcc-12.0.0_pre/configure --host=sparc-unknown-linux-gnu --build=sparc-unknown-linux-gnu --prefix=/usr --bindir=/usr/sparc-unknown-linux-gnu/gcc-bin/12.0.0 --includedir=/usr/lib/gcc/sparc-unknown-linux-gnu/12.0.0/include --datadir=/usr/share/gcc-data/sparc-unknown-linux-gnu/12.0.0 --mandir=/usr/share/gcc-data/sparc-unknown-linux-gnu/12.0.0/man --infodir=/usr/share/gcc-data/sparc-unknown-linux-gnu/12.0.0/info --with-gxx-include-dir=/usr/lib/gcc/sparc-unknown-linux-gnu/12.0.0/include/g++-v12 --with-python-dir=/share/gcc-data/sparc-unknown-linux-gnu/12.0.0/python --enable-languages=c,c++,fortran --enable-obsolete --enable-secureplt --disable-werror --with-system-zlib --disable-nls --disable-libunwind-exceptions --enable-checking=release --with-bugurl=https://bugs.gentoo.org/ --with-pkgversion=Gentoo 12.0.0_pre, commit b77e3b4e4589e56c01511fabdbaadb029cd47f5c --disable-esp --enable-libstdcxx-time --disable-libstdcxx-pch --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --disable-multilib --disable-fixed-point --enable-targets=all --enable-libgomp --disable-libssp --disable-libada --disable-cet --disable-systemtap --disable-valgrind-annotations --disable-vtable-verify --disable-libvtv --without-zstd --enable-lto --with-isl --disable-isl-version-check --enable-default-pie --enable-default-ssp I can still trigger the warning: cd /tmp/cmtest/Source && /usr/bin/c++ -DCURL_STATICLIB -DLIBARCHIVE_STATIC -D_FILE_OFFSET_BITS=64 -I/tmp/cmtest/Utilities -I/tmp/cmtest/Source -I/home/buildbot/repos/CMake/Source -I/home/buildbot/repos/CMake/Source/LexerParser -I/home/buildbot/repos/CMake/Source/CTest -I/home/buildbot/repos/CMake/Source/CPack -isystem /home/buildbot/repos/CMake/Utilities/std -isystem /home/buildbot/repos/CMake/Utilities -Wnon-virtual-dtor -Wcast-align -Wchar-subscripts -Wall -W -Wshadow -Wpointer-arith -Wformat-security -Wundef -g -std=c++17 -MD -MT Source/CMakeFiles/CMakeLib.dir/cmLocalUnixMakefileGenerator3.cxx.o -MF CMakeFiles/CMakeLib.dir/cmLocalUnixMakefileGenerator3.cxx.o.d -o CMakeFiles/CMakeLib.dir/cmLocalUnixMakefileGenerator3.cxx.o -c /home/buildbot/repos/CMake/Source/cmLocalUnixMakefileGenerator3.cxx -Wformat-truncation=2 I still have the full gcc build log if that matters.
[Bug middle-end/104069] -Werror=use-after-free false positive on elfutils-0.186
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104069
Rolf Eike Beer changed:
What|Removed |Added
CC||e...@sf-mail.de
--- Comment #23 from Rolf Eike Beer ---
Using gcc12 from 4943b75e9f06f0b64ed541430bb7fbccf55fc552.
$ cat rea.c
#include
char *
compact_buffer(char *inbuf, size_t oldlen, size_t k)
{
char *foo;
#ifdef WARN
char **buf = &foo;
#endif
foo = realloc(inbuf, k);
if (foo == NULL) {
#if defined(WARN) && defined(WARN2)
foo = inbuf;
return inbuf;
#else
return inbuf;
#endif
}
return foo;
}
$ gcc-12.0.1 -c -Wuse-after-free=3 -Irepos/Qsmtp/include rea.c
$ gcc-12.0.1 -c -DWARN -Wuse-after-free=2 -Irepos/Qsmtp/include rea.c
rea.c: In function 'compact_buffer':
rea.c:17:24: warning: pointer 'inbuf' may be used after 'realloc'
[-Wuse-after-free]
17 | return inbuf;
|^
rea.c:11:15: note: call to 'realloc' here
11 | foo = realloc(inbuf, k);
| ^
$ gcc-12.0.1 -c -DWARN -DWARN2 -Wuse-after-free=2 -Irepos/Qsmtp/include rea.c
rea.c: In function 'compact_buffer':
rea.c:15:24: warning: pointer 'inbuf' may be used after 'realloc'
[-Wuse-after-free]
15 | return inbuf;
|^
rea.c:11:15: note: call to 'realloc' here
11 | foo = realloc(inbuf, k);
| ^
rea.c:14:21: warning: pointer 'inbuf' may be used after 'realloc'
[-Wuse-after-free]
14 | foo = inbuf;
| ^~~
rea.c:11:15: note: call to 'realloc' here
11 | foo = realloc(inbuf, k);
| ^
[Bug bootstrap/111642] [14 Regression] profiledbootstrap failure: poly-int.h:453:5: error: too many initializers for ‘long int [1]’ (possibly since r14-4339-geaa41a6dc127d8)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111642
Rolf Eike Beer changed:
What|Removed |Added
CC||e...@sf-mail.de
--- Comment #2 from Rolf Eike Beer ---
Just hit the one in simplify-rtx.cc on Linux/sparc64:
In file included from
/var/tmp/portage/sys-devel/gcc-14.0.0./work/gcc-14.0.0./gcc/coretypes.h:480,
from
/var/tmp/portage/sys-devel/gcc-14.0.0./work/gcc-14.0.0./gcc/simplify-rtx.cc:23:
/var/tmp/portage/sys-devel/gcc-14.0.0./work/gcc-14.0.0./gcc/poly-int.h:
In instantiation of ‘constexpr poly_int::poly_int(poly_int_full, const
Cs& ...) [with Cs = {int, int}; unsigned int N = 1; C = long int]’:
/var/tmp/portage/sys-devel/gcc-14.0.0./work/gcc-14.0.0./gcc/poly-int.h:439:13:
required from here
/var/tmp/portage/sys-devel/gcc-14.0.0./work/gcc-14.0.0./gcc/simplify-rtx.cc:8692:25:
in ‘constexpr’ expansion of ‘poly_int<1, long int>(1, 1)’
/var/tmp/portage/sys-devel/gcc-14.0.0./work/gcc-14.0.0./gcc/poly-int.h:453:5:
error: too many initializers for ‘long int [1]’
453 | : coeffs { (typename poly_coeff_traits::
| ^
454 | template init_cast::type (cs))... } {}
| ~~~
