Did the LLVM folks fix the C++ structured exception handling incompatibility between MSVC compiled DLLs/programs and LLVM compiled ones? This was a problem for many years.
(To the extent possible. There are some edge cases left, but they're very rare. Essentially all the real-world code we've seen works now.)
From that document:
Asynchronous Exceptions (SEH): Partial. Structured exceptions (__try / __except / __finally) mostly work on x86 and x64. LLVM does not model asynchronous exceptions, so it is currently impossible to catch an asynchronous exception generated in the same frame as the catching __try.