llvm-project

4e2efa55 - [llvm] export private symbols needed by unittests (#145767)

[llvm] export private symbols needed by unittests (#145767) ## Purpose Export a small number of private LLVM symbols so that unit tests can still build/run when LLVM is built as a Windows DLL or a shared library with default hidden symbol visibility. ## Background The effort to build LLVM as a WIndows DLL is tracked in #109483. Additional context is provided in [this discourse](https://discourse.llvm.org/t/psa-annotating-llvm-public-interface/85307). Some LLVM unit tests use internal/private symbols that are not part of LLVM's public interface. When building LLVM as a DLL or shared library with default hidden symbol visibility, the symbols are not available when the unit test links against the DLL or shared library. This problem can be solved in one of two ways: 1. Export the private symbols from the DLL. 2. Link the unit tests against the intermediate static libraries instead of the final LLVM DLL. This PR applies option 1. Based on the discussion of option 2 in #145448, this option is preferable. ## Overview * Adds a new `LLVM_ABI_FOR_TEST` export macro, which is currently just an alias for `LLVM_ABI`. * Annotates the sub-set of symbols under `llvm/lib` that are required to get unit tests building using the new macro.