rjmccall added a comment. In https://reviews.llvm.org/D40508#938854, @sepavloff wrote:
> In https://reviews.llvm.org/D40508#938686, @rjmccall wrote: > > > In https://reviews.llvm.org/D40508#938675, @sepavloff wrote: > > > > > In https://reviews.llvm.org/D40508#938040, @rjmccall wrote: > > > > > > > My skepticism about the raw_ostream is not about the design of having a > > > > custom raw_ostream subclass, it's that that subclass could conceivably > > > > be re-used by some other client. It feels like it belongs as an > > > > internal hack in Clang absent some real evidence that someone else > > > > would use it. > > > > > > > > > This class can be helpful in various cases where string identifier must > > > persistently identify an object and memory consumption must be low. It > > > may be: > > > > > > - If we introduce an option that allows a user to specify how many > > > symbols of full type name are kept in abbreviated name, then `llvm-link` > > > may see types named as `foo<int>` and > > > `2544896211ff669ed44dccd265f4c9163b340190`, if they come from modules > > > compiled with different options. To find out that these are the same > > > type, it must have access to the same machinery. > > > > > > The LLVM linking model does not actually depend on struct type names > > matching. My understanding is that, at best, it uses that as a heuristic > > for deciding whether to make an effort to unify two types, but it's not > > something that's ultimately supposed to impact IR semantics. > > > It is mainly true with an exception, when `llvm-link` resolves opaque types > it relies on type name only. And this behavior creates the issue that > https://reviews.llvm.org/D40567 tries to resolve. It is not clear from that report what the actual problem is. Two incomplete types get merged by the linker? So what? >> If we needed IR type names to match reliably, we would use a mangled name, >> not a pretty-print. > > There is no requirement for IR type name to be an identifier, so pretty-print > fits the need of type identification. Not really; pretty-printing drops a lot of information that is pertinent in a stable identifier, like scopes and so on, and makes arbitrary decisions about other things, like where to insert spaces, namespace qualifiers, etc. https://reviews.llvm.org/D40508 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
