joaomoreira added inline comments.
================ Comment at: llvm/lib/Target/X86/X86AsmPrinter.cpp:121 + if (N == Value) + return ~Value; + } ---------------- samitolvanen wrote: > joaomoreira wrote: > > Can we use another constant blinding scheme, such as a Value++ or anything > > else? This way, we would prevent endbrs from being emitted in the indirect > > branch guards too. > > > > Since we are using Value (prologue) and ~Value (caller/guard) for doing the > > checks, we also need to check if ~ENDBR was picked as a KCFIType, otherwise > > ENDBR will be emitted in the ibranch guards. > > Can we use another constant blinding scheme, such as a Value++ or anything > > else? This way, we would prevent endbrs from being emitted in the indirect > > branch guards too. > > > > Since we are using Value (prologue) and ~Value (caller/guard) for doing the > > checks, we also need to check if ~ENDBR was picked as a KCFIType, otherwise > > ENDBR will be emitted in the ibranch guards. > > I don't mind changing this to `Value + 1`, but that actually doesn't change > anything because we emit `-Value` in indirect call checks, not `~Value`. > Therefore, using `~Value` works equally well here. > > Specifically, this code currently emits `~Value`in the preamble and > `-(~Value) == Value + 1` in the indirect call check. Switching to `Value + 1` > simply reverses the order; we'll emit `Value + 1` in the preamble and > `-(Value + 1) == ~Value` in the indirect call check. > > However, you are right that we also need to avoid `-ENDBR` in this function. > I'll fix that and clarify the comment. Oops, got confused with the operands, tks for clearing it up. Otherwise, changes LGTM. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D119296/new/ https://reviews.llvm.org/D119296 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
