[llvm-branch-commits] [libc++] Annotate classes with _LIBCPP_PFP to enable pointer field protection (PR #151652)

[Louis Dionne via llvm-branch-commits]

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@@ -210,3 +210,17 @@ prevent compilers from generating said debug information. Aliases inside type tr
 should be annotated for the same reason.
 
 This is enforced by the clang-tidy check ``libcpp-nodebug-on-aliases``.
+
+Pointer field protection
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ldionne wrote:

I don't think we have much precedent for codifying support for an extension like this in our coding guidelines. I think it's a good idea to do it if we're going to try to support it, but I'd like to capture something about this being done on a best effort basis. Otherwise, the implication is that a patch could be e.g. reverted or blocked because the attribute hasn't been applied properly, which would now contradict our coding guidelines.

Another path forward, which I like even more, would be that if we can actually capture those rules into something systematic, we can add a clang-tidy check that catches when we forget to apply the attribute, and then that becomes a solid guarantee that these annotations are going to be added when they are needed (and it requires even less thinking from contributors). WDYT?

https://github.com/llvm/llvm-project/pull/151652