AaronBallman wrote: > I have started to implement defining the -Wformat-signedness option config in > clang/include/clang/Basic/DiagnosticSemaKinds.td as suggested originally by > @hazohelet and I agree that the implementation is a lot cleaner that way. > However before finishing implementing that I think we need to conclude what > level of gcc compatibility that we aim for in clang. > > Below I list the characteristics of -Wformat-signedness that I have seen by > testing it out in gcc and reading the gcc documentation (I have not inspected > the gcc source code): > > 1. The option -Wformat-signedness is default off. > > 2. The -Wformat-signedness warnings are not enabled alone by the -Wformat > option. > > 3. The -Wformat-signedness warnings are not enabled alone by the > -Wformat-signedness option. > > 4. The -Wformat-signedness warnings are enabled by the option -Wformat > together with the option -Wformat-signedness. > > 5. Parts of the -Wformat-signedness warnings (regarding scanf) are > enabled by the options -Wformat together with the option -pedantic. > > 6. Warnings produced by -Wformat-signedness is reported as a -Wformat > warnings (e.g "warning: format ‘%u’ expects argument of type ‘unsigned int’, > but argument 2 has type ‘int’ [-Wformat=]" > > 7. Warnings produced by -Wformat-signedness can be suppressed by "#pragma > GCC diagnostic ignored -Wformat" > > > Which of the above points are important for us to follow in clang to get a > reasonable gcc compatibility? To me I think point 1, 2 and maybe 7 is the > most important to follow.
I agree, 1, 2, 4 (same idea as 2, basically), and 7 are the critical things we'd need for compatibility. I personally find 3, 5, and 6 to be kind of strange behavior though I can see how it would arise. https://github.com/llvm/llvm-project/pull/74440 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
