ahatanak added a comment. The use case for this is a macro in which the call to `__builtin_os_log_format` that writes to the buffer and the call that uses the buffer appear in two different statements. For example:
__builtin_os_log_format(buf, "%@", getObj()); ... use_buffer(buf); The object returned by the call to `getObj` has to be kept alive until `use_buffer` is called, but currently it gets destructed at the end of the full expression. I think an alternate solution would be to provide users a means to tell ARC optimizer not to move the release call for a local variable past any calls, i.e., something that is stricter than `NS_VALID_UNTIL_END_OF_SCOPE`, but that places more burden on the users. In the `os_log` macro, the result of the call to `__builtin_os_log_format` is passed directly to the call that uses the buffer, so it doesn't require any lifetime extension as you pointed out. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D83997/new/ https://reviews.llvm.org/D83997 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
