[PATCH] D100919: [AArch64] Support customizing stack protector guard

Tue May 4 17:53:42 PDT 2021

nickdesaulniers added inline comments.

================
Comment at: llvm/lib/Target/AArch64/AArch64InstrInfo.cpp:1914-1915
+      BuildMI(MBB, MI, DL, get(AArch64::LDRXui))
+          .addReg(Reg, getKillRegState(false))
+          .addReg(Reg, RegState::Define)
+          .addImm(Options.StackProtectorGuardOffset >> 3);
----------------
nickdesaulniers wrote:
> nickdesaulniers wrote:
> > nickdesaulniers wrote:
> > > @efriedma can you please check that I have these flags correct? I'm not sure that I do.  Also, I suspect that I can't allocated a virtual register for the result of the LDR, since this is post-RA?
> > @efriedma bumping for review; otherwise can you suggest another reviewer?
> In particular, I'm most curious about the use of `RegState::Renamable`; the result of reading via `mrs` is a temporary; but this is post-RA, so isn't it too late for further register renaming?
Additionally, if it's a temporary, should it be `RegState::Implicit`?

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D100919/new/

https://reviews.llvm.org/D100919