In D76527, we stopped exporting symbols from clang, opt and llc unless
the LLVM_ENABLE_PLUGINS cmake variable is true (which causes clang's
own plugin collection to be built).
But another reasonable build configuration is to ask clang to export
its symbols for out-of-tree plugins to use, without building the
in-tree ones. That is, you might set LLVM_EXPORT_SYMBOLS_FOR_PLUGINS
without also setting LLVM_ENABLE_PLUGINS (at least if you're using
MSVC, where you need to ask explicitly for the symbols to be
In that situation, the symbols should still be exported, but after
D76527, they weren't being.