[PATCH] D81474: Handle delayed-template-parsing functions imported into a non-dtp TU

[Kadir Cetinkaya via Phabricator via cfe-commits]

kadircet accepted this revision.
kadircet added a comment.
This revision is now accepted and ready to land.

Looking at this some more, it looks like whenever clang is building a TU prefix(preamble), the assumption is that any delayed templates will be parsed at the end of the TU. That is unfortunately not true, if the rest of the TU is built with no-delayed-template-parsing. (as you've already said in the description)

This suggests that DelayedTemplateParsing shouldn't be a benign langopt. But since it is, we should be setting late template parser at the end of TU if there are any delayed templates coming from either the preamble or in the rest of the TU.
The latter is already done by checking for langopt, we can check for the former using `Actions.ExternalSemaSource`. But in the absence of delayed templates, setting the parser is (currently) a no-op. So setting it all the time should hopefully be OK.
Hence LGTM.

Another option would be to change preamble building logic to parse all the late parsed templates at the end, instead of just serializing the tokens. That sounds like a more intrusive change though, so I am more comfortable with current one.


Repository:
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  https://reviews.llvm.org/D81474/new/

https://reviews.llvm.org/D81474