[clang] [llvm] [PAC][Driver] Support `pauthtest` ABI for AArch64 Linux triples (PR #97237)

[Peter Smith via cfe-commits]

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@@ -1546,16 +1581,28 @@ static void CollectARMPACBTIOptions(const ToolChain &TC, const ArgList &Args,
 
   CmdArgs.push_back(
       Args.MakeArgString(Twine("-msign-return-address=") + Scope));
-  if (Scope != "none")
+  if (Scope != "none") {
+    if (Triple.getEnvironment() == llvm::Triple::PAuthTest)
+      D.Diag(diag::err_drv_unsupported_opt_for_target)
+          << A->getAsString(Args) << Triple.getTriple();
     CmdArgs.push_back(
         Args.MakeArgString(Twine("-msign-return-address-key=") + Key));
-  if (BranchProtectionPAuthLR)
+  }
+  if (BranchProtectionPAuthLR) {
+    if (Triple.getEnvironment() == llvm::Triple::PAuthTest)
+      D.Diag(diag::err_drv_unsupported_opt_for_target)
+          << A->getAsString(Args) << Triple.getTriple();
     CmdArgs.push_back(
         Args.MakeArgString(Twine("-mbranch-protection-pauth-lr")));
+  }
   if (IndirectBranches)
     CmdArgs.push_back("-mbranch-target-enforce");
-  if (GuardedControlStack)
+  if (GuardedControlStack) {
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smithp35 wrote:

I think GuardedControlStack should be compatible with PAuthABI but there won't be hardware available for some time so we could retrospectively support it later after testing it.

Perhaps worth a comment that GCS is untested with PAuthABI, but could be enabled after testing with a suitable system.

https://github.com/llvm/llvm-project/pull/97237