[all-commits] [llvm/llvm-project] 61c7a9: Commit to a primary definition for a class when we...

[Richard Smith via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 61c7a9140becb19c5b1bc644e54452c6f782f5d5
      https://github.com/llvm/llvm-project/commit/61c7a9140becb19c5b1bc644e54452c6f782f5d5
  Author: Richard Smith <richard at metafoo.co.uk>
  Date:   2023-07-25 (Tue, 25 Jul 2023)

  Changed paths:
    M clang/docs/ReleaseNotes.rst
    M clang/lib/Serialization/ASTReaderDecl.cpp

  Log Message:
  -----------
  Commit to a primary definition for a class when we load its first
member.

Previously, we wouldn't do this if the first member loaded is within a
definition that's added to a class via an update record, which happens
when template instantiation adds a class definition to a declaration
that was imported from an AST file.

This would lead to classes having member functions whose getParent
returned a class declaration that wasn't the primary definition, which
in turn caused the vtable builder to build broken vtables.

I don't yet have a reduced testcase for the wrong-code bug here, because
the setup required to get us into the broken state is very subtle, but
have confirmed that this fixes it.