Cross-DSO control flow integrity (LLVM part).

An LTO pass that generates a __cfi_check() function that validates a
call based on a hash of the call-site-known type and the target
pointer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255693 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed