https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110617
--- Comment #12 from Xi Ruoyao <xry111 at gcc dot gnu.org> --- (In reply to Florian Weimer from comment #11) > (In reply to Xi Ruoyao from comment #10) > > But Zack's reason against using __nonnull is __nonnull may cause unwanted > > optimizations to *the user code*. > > GCC already offers options to control function call behavior in the presence > of nonnull attributes: > > For function calls: > • If the compiler determines that a null pointer is passed in an > argument slot marked as non-null, and the ‘-Wnonnull’ option > is enabled, a warning is issued. *Note Warning Options::. > • The ‘-fisolate-erroneous-paths-attribute’ option can be > specified to have GCC transform calls with null arguments to > non-null functions into traps. *Note Optimize Options::. > • The compiler may also perform optimizations based on the > knowledge that certain function arguments cannot be null. > These optimizations can be disabled by the > ‘-fno-delete-null-pointer-checks’ option. *Note Optimize > Options::. > > So I don't think we need another way to disable nonnull attributes in > installed glibc headers. Ah indeed, I only remembered "-fisolate-erroneous-paths-attribute" but not "-fno-delete-null-pointer-checks".
