Enable IBT(Indirect Branch Tracking) in JIT with CET(Control-flow Enforcement Technology)
This patch comes from H.J.'s https://github.com/hjl-tools/llvm-project/commit/2bd54ce7fa9e94fcd1118b948e14d1b6fc54dfd2
This patch fix the failed llvm unit tests which running on CET machine. (e.g. ExecutionEngine/MCJIT/MCJITTests)
The reason we enable IBT at "JIT compiled with CET" is mainly that: the JIT don't know the its caller program is CET enable or not.
If JIT's caller program is non-CET, it is no problem JIT generate CET code or not.
But if JIT's caller program is CET enabled, JIT must generate CET code or it will cause Control protection exceptions.
I have test the patch at llvm-unit-test and llvm-test-suite at CET machine. It passed.
and H.J. also test it at building and running VNCserver(Virtual Network Console), it works too.
(if not apply this patch, VNCserver will crash at CET machine.)
Reviewers: hjl.tools, craig.topper, LuoYuanke, annita.zhang, pengfei
Subscribers: tstellar, efriedma, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D76900