Hi, On Fri, 2023-12-01 at 13:09 +0100, Jakub Jelinek via Gcc wrote: > On Fri, Dec 01, 2023 at 01:03:01PM +0100, Jan Hubicka via Gcc wrote: > > > On Dez 01 2023, Richard Biener via Gcc wrote: > > > > > > > Hmm, so why's it then referenced and not "GCed"? > > > > > > This has nothing to do with garbage collection. It's just the way > > > libgcc avoids having too many source files. It would be exactly the > > > same if every function were in its own file. > > > > THe ifdef machinery makes every function to go insto its own .o file > > which are then archived. So if user code never calls to fork, the .o > > file with fork wrapper should not be picked by linker and we should not > > have link error. > > > > If user code calls fork, then the .o file with wrapper should be picked > > and we will get linker error on missing fork. So I think it ought to > > work as it is now. Does mingw linker behave somehow differently with > > archives? Or is there problem with a libgcov being DLL or something? > > The problem is that the changes to switch to modern C result in calls to > unprototyped function being an error rather than just warning as before. > int foo (void) { return fork (); } > warning: implicit declaration of function ‘fork’ > [-Wimplicit-function-declaration] > previously, now > error: implicit declaration of function ‘fork’ > [-Wimplicit-function-declaration] > (by default in C99+). > > So, as has been discussed earlier, either we should use __builtin_fork () > rather than fork (), or we need in configure to test for fork prototype and > if missing, prototype it ourselves, or ensure _gcov_fork.o is not compiled > on targets which don't have fork prototyped.
BTW. The gcc-fedora-mingw buildbot has been broken because of this issue for the last week: https://builder.sourceware.org/buildbot/#/builders/gcc-fedora-mingw ../../../gcc/libgcc/libgcov-interface.c: In function '__gcov_fork': ../../../gcc/libgcc/libgcov-interface.c:185:9: error: implicit declaration of function 'fork' [-Wimplicit-function-declaration] 185 | pid = fork (); | ^~~~ make[2]: *** [Makefile:935: _gcov_fork.o] Error 1 Cheers, Mark