================
@@ -1537,11 +1570,16 @@ static void CollectARMPACBTIOptions(const ToolChain
&TC, const ArgList &Args,
if (!isAArch64 && PBP.Key == "b_key")
D.Diag(diag::warn_unsupported_branch_protection)
<< "b-key" << A->getAsString(Args);
+ if (!isAArch64 && PBP.HasPauthABI)
+ D.Diag(diag::warn_unsupported_branch_protection)
+ << "pauthabi" << A->getAsString(Args);
Scope = PBP.Scope;
Key = PBP.Key;
BranchProtectionPAuthLR = PBP.BranchProtectionPAuthLR;
IndirectBranches = PBP.BranchTargetEnforcement;
GuardedControlStack = PBP.GuardedControlStack;
+ if (isAArch64 && PBP.HasPauthABI)
----------------
kovdan01 wrote:
@DanielKristofKiss Thanks! Yes, I now see that authenticating branch
instructions also set the `PSTATE.BTYPE`. So, I agree that we can allow
pauthabi+bti. The codegen when `pauthabi+bti` is passed as branch protection
looks OK on downstream:
- for functions which do not sign LR (w/o `pacibsp` in the beginning, e.g. leaf
functions), a proper `bti` instruction is emitted in the beginning of the
function;
- for function which sign LR (with `pacibsp` in the beginning), no additional
`bti` instruction is emitted since `pacibsp` also has `bti` built-in, see
`SetBTypeCompatible` in
https://developer.arm.com/documentation/ddi0602/2022-06/Base-Instructions/PACIB--PACIB1716--PACIBSP--PACIBZ--PACIZB--Pointer-Authentication-Code-for-Instruction-address--using-key-B-
In mainline, codegen with `-fptrauth-returns` is not implemented yet, so I
can't provide tests verifying generated assembly correctness right now. I'll
add them as soon as codegen support for this flag is merged.
I've implemented a check which only allows `bti` with `pauthabi` and does not
allow `pac-ret[+leaf,+pc,+b-key]` and `gcs`. See
3067c934a957eed21cb3ae73404675242425e5cb
Tagging @smithp35
https://github.com/llvm/llvm-project/pull/97237
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