[PATCH] D138546: Clangd: Preserve target flags in system includes extractor

[Nathan Ridge via Phabricator via llvm-commits]

nridge added a comment.

In D138546#4075681 <https://reviews.llvm.org/D138546#4075681>, @cpsauer wrote:

> Sounds like you're not concerned, then, that the JSONCompilationDatabasePlugin will get invoked and the results then passed to a SystemIncludeExtractor-enabled mangler?
> (I'd seen some fallback calls into the plugin registry in GlobalCompilationDatabase, hence the original change, but, lacking broader context, I was having trouble tracing the expected control flow.)

I did initially overlook the mentioned fallback codepath <https://searchfox.org/llvm/rev/eb8fcc1e835acc1f9ea1cb43902672dd9511d66b/clang-tools-extra/clangd/GlobalCompilationDatabase.cpp#317-339>, thanks for catching that. However, it looks like it's only taken if we've already explicitly checked for `compile_commands.json` and didn't find one, so `JsonCompilationDatabasePlugin` won't find anything either (i.e. the fallback is for potential other plugins).

As for consumers of the plugin registry outside of clangd, we can assume they won't use `SystemIncludeExtractor` which is currently a clangd-internal component. (There has been an idea floated about upstreaming `SystemIncludeExtractor` from clangd to libTooling, but it remains to be determined how that would look at the API level, and we can make adjustments as necessary if/when that happens.)

Anyways, +1 from me on the TargetAndMode related changes.


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https://reviews.llvm.org/D138546