[PATCH] D41723: Introduce the "retpoline" x86 mitigation technique for variant #2 of the speculative execution vulnerabilities disclosed today, specifically identified by CVE-2017-5715, "Branch Target Injection", and is one of the two halves to Spectre..

[Zach Riggle via Phabricator via llvm-commits]

zachriggle added a comment.

Pardon my unsolicited comment, but it seems to me that using a "retpoline" will have two unintended negative side-effects:

1. It will ~neuter Control Flow Integrity by providing a "universal" gadget that pulls a call target off the stack and is allowed to call anything
2. It will break performance-counter-based ROP detection


https://reviews.llvm.org/D41723