[AArch64] Branch Protection and Return Address Signing B Key Support

- Add support for -mbranch-protection=<type>[+<type>]* where
  - <type> ::= [standard, none, bti, pac-ret[+b-key,+leaf]*]
- The protection emits relevant function attributes
  - sign-return-address=<scope>
  - sign-return-address-key=<key>
  - branch-protection

llvm-svn: 345273
11 files changed
tree: 84d95e34416176115f0c422aa5fdb1e1cc7e711f
  1. clang/
  2. clang-tools-extra/
  3. compiler-rt/
  4. debuginfo-tests/
  5. libclc/
  6. libcxx/
  7. libcxxabi/
  8. libunwind/
  9. lld/
  10. lldb/
  11. llgo/
  12. llvm/
  13. openmp/
  14. parallel-libs/
  15. polly/
  16. README.md
README.md

The LLVM Compiler Infrastructure

This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments.