This implementation of objc_exception_throw constructs a
_CxxThrowException-compatible ThrowInfo based on the runtime type of the
passed-in exception. Everything pertaining to the exception is allocated
on the stack before the call and destroyed when/if the stack frame is
aborted.
The construction of ThrowInfo, CatchableTypes, and TypeDescriptors, as
well as mangling, is compatible with Clang/LLVM's MicrosoftCXXABI
exception generator.
This ties Objective-C exceptions on Windows to the C++ exception model,
which allows us to support (unboxed) foreign exceptions and C++ catch of
Objective-C types.
objc_exception_rethrow recycles MicrosoftCXXABI's rethrow.
Contributing-author: Jordan Saunders <jmsaunde@microsoft.com>
Contributing-author: Shayne Hiet-Block <shaynehi@microsoft.com>
Dustin L. Howett