[PATCH] D108689: [Linker] Support weak symbols in nodeduplicate COMDAT group

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added a comment.

The description should call out that with current IR, a generic `comdat nodeduplicate` for regular LTO is not representable.

In the linker, sections and symbols are separate concepts. A dropped weak symbol does not force the drop of the defining input section (though can be collected by GC).
While in the IR, when a weak linkage symbol is dropped, its associate section content is dropped as well.
profc and profd must be parallel, so we need to be careful.
For their regular LTO behavior, a `comdat any` happens to work because we don't really the need other members in the comdat whose leader is weak.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D108689/new/

https://reviews.llvm.org/D108689