beccadax added a comment. In D112773#3096185 <https://reviews.llvm.org/D112773#3096185>, @aaron.ballman wrote:
> `swift_attr` has no subjects, so this will attempt to spray the attribute > onto literally *everything*. That makes this incredibly risky to use with the > pragma approach (not to mention what it could do to memory consumption of > large ASTs). I'm not certain I'm comfortable allowing this without an > explicit set of subjects for the attribute. What exactly is the risk here? In my testing, omitting `apply_to` or setting it to `any` or `any()` caused clang to apply the attribute to nothing, not everything. If there is a way I didn't find, perhaps we could address that by emitting a warning if you use the "match anything" subject with an attribute that has an empty subject list. > Can we add subjects to this attribute to try to limit the damage somewhat? I don't think we can, because `swift_attr` is by design very widely applicable—it allows you to apply arbitrary Swift language features to the imported representation of any Clang declaration. Any declaration Swift imports, including types and typedefs, functions, non-local variables, and parameters, ought to accept it. Looking through the subject matchers available, almost everything would at least //theoretically// be a reasonable target for `swift_attr` (`variable(is_local)` is the only exception I noticed). We could restrict it to only declarations we're currently using it for, but many of these (e.g. C++ declarations) are likely to be supported in the future, so this would create clang churn and integration issues as Swift's capabilities expand. So I don't think the risk you're worried about is really there, and I don't think adding a subject list would mitigate it very much. But if I've missed something, please point it out. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D112773/new/ https://reviews.llvm.org/D112773 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
