[ARM] Implement setjmp BTI placement for PACBTI-M
This patch intends to guard indirect branches performed by longjmp
by inserting BTI instructions after calls to setjmp.
Calls with 'returns-twice' are lowered to a new pseudo-instruction
named t2CALL_BTI that is later expanded to a bundle of {tBL,t2BTI}.
This patch is part of a series that adds support for the PACBTI-M extension of
the Armv8.1-M architecture, as detailed here:
https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/armv8-1-m-pointer-authentication-and-branch-target-identification-extension
The PACBTI-M specification can be found in the Armv8-M Architecture Reference
Manual:
https://developer.arm.com/documentation/ddi0553/latest
The following people contributed to this patch:
- Alexandros Lamprineas
- Ties Stuij
Reviewed By: labrinea
Differential Revision: https://reviews.llvm.org/D112427
12 files changed: