teresajohnson wrote: > > I assume this will give a duplicate symbol linker error if used > > inappropriately? Any chance of more subtle bugs? > > As far as LTO is concerned I think it can only result in a duplicate symbol > error as the resulting symbols will have external strong linkage. There are > two non-LTO uses of `getModuleUniqueId` in the tree: > > * The PowerPC AsmPrinter. It looks like this one is used to produce symbols > with external linkage, so the usage error would be detected at link time. > * The ASan pass. It's unclear what would happen if used incorrectly (a > discarded section error I think?) but it doesn't look like we can do much > about it anyway because LTO isn't necessarily enabled with ASan.
Could that be addressed by only allowing this flag under LTO? > > > Should there be some error detection at LTO link time? I.e. if the module > > flag is set on the LTO linked modules can and should we detect and error on > > duplicate source file names? > > I don't think it is needed as the LTO-specific cases are already detectable. Probably at least add a note to the new documentation for the option that it will result in linker errors if used inappropriately. I was mostly thinking that detecting and erroring at LTO time would result in a clearer error (like at the start of LTO::addModule, where it is looking for partially split LTO units, which we do by adding the module flag to the index flags). E.g. I could see a case where someone adds this option to their makefiles, time passes and they forget about it, a new file is added that violates the constraints, and boom they get a linker error that they don't understand (and then the compiler gets an bug report). https://github.com/llvm/llvm-project/pull/135728 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
