https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90347
Bug ID: 90347 Summary: [UBSAN] __attribute__((weak))__ results in "declared weak after being used" error Product: gcc Version: 10.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: sanitizer Assignee: unassigned at gcc dot gnu.org Reporter: dimhen at gmail dot com CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org, jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at gcc dot gnu.org Target Milestone: --- $ cat x.cpp struct s { }; extern s var; // __attribute__ ((weak)) s var; // no error extern void foo(s&); void bar() { foo(var); } __attribute__ ((weak)) s var; // error $ /usr/local/gcc_current/bin/g++ -fsanitize=undefined -Wall -c x.cpp x.cpp:2:10: error: 'var' declared weak after being used 2 | extern s var; | ^~~ $ /usr/local/gcc_current/bin/g++ -Wall -c x.cpp $ $ /usr/local/gcc_current/bin/g++ -v Using built-in specs. COLLECT_GCC=/usr/local/gcc_current/bin/g++ COLLECT_LTO_WRAPPER=/usr/local/gcc_current/libexec/gcc/x86_64-pc-linux-gnu/10.0.0/lto-wrapper OFFLOAD_TARGET_NAMES=nvptx-none Target: x86_64-pc-linux-gnu Configured with: /home/dimhen/src/gcc_current/configure --prefix=/usr/local/gcc_current --enable-checking=yes,df,fold,rtl,extra --enable-languages=c,c++,lto --disable-multilib --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-gnu-unique-object --enable-linker-build-id --with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --with-isl --enable-offload-targets=nvptx-none --without-cuda-driver --enable-gnu-indirect-function --with-tune=native Thread model: posix gcc version 10.0.0 20190503 (experimental) [trunk revision 270859] (GCC)