nickdesaulniers added a comment. In D134461#3815458 <https://reviews.llvm.org/D134461#3815458>, @aaron.ballman wrote:
> In D134461#3815298 <https://reviews.llvm.org/D134461#3815298>, @nathanchance > wrote: > >> This warning is quite noisy for the Linux kernel due to a couple of places >> where a `void *` is dereferenced as part of compile time checking. > > Thank you for letting us know! In particular offsetof and __is_constexpr are _heavily_ used throughout the codebase. > This one is interesting to me -- I was on the fence about whether we want to > diagnose this in an unevaluated context or not. The > `clang/test/Analysis/misc-ps.m` test was why I was considering it, and I > eventually convinced myself that the dereference there was a harmless UB when > we support pointer arithmetic on void as an extension, but UB nonetheless. > Now I wonder whether we want different behavior in the `sizeof` case -- it > seems odd to me that we warn by default on `sizeof(*vp)` but not > `sizeof(void)`: https://godbolt.org/z/PcMrW7b5W so I think we might want to > silence `sizeof(*vp)` diagnostics. > > WDYT? SGTM > All this said, I think in both cases we want `-pedantic` to warn on these > situations even if we would silence by default. e.g., > > void func(void *vp) { > sizeof(void); // No warning by default, does get pedantic warning > sizeof(*vp); // No warning by default, does get pedantic warning > sizeof(*(vp))`; // No warning by default, does get pedantic warning > void inner(typeof(*vp)); // No warning by default, does get pedantic > warning > > (void)*vp; // Warning by default > } > > What do folks think of that idea? SGTM; either warn via -Wpedantic or silenced with -Wno-gnu. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D134461/new/ https://reviews.llvm.org/D134461 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
