[llvm-branch-commits] [llvm] [AArch64][PAC] Lower authenticated calls with ptrauth bundles. (PR #85736)

[Daniil Kovalev via llvm-branch-commits]

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@@ -1012,25 +1014,37 @@ bool AArch64CallLowering::isEligibleForTailCallOptimization(
 }
 
 static unsigned getCallOpcode(const MachineFunction &CallerF, bool IsIndirect,
-                              bool IsTailCall) {
+                              bool IsTailCall,
+                              std::optional<CallLowering::PointerAuthInfo> &PAI,
+                              MachineRegisterInfo &MRI) {
   const AArch64FunctionInfo *FuncInfo = CallerF.getInfo<AArch64FunctionInfo>();
 
-  if (!IsTailCall)
-    return IsIndirect ? getBLRCallOpcode(CallerF) : (unsigned)AArch64::BL;
+  if (!IsTailCall) {
+    if (!PAI)
+      return IsIndirect ? getBLRCallOpcode(CallerF) : (unsigned)AArch64::BL;
+
+    assert(IsIndirect && "authenticated direct call");
+    assert(PAI->Key == 0 || PAI->Key == 1 && "invalid ptrauth key");
+    return AArch64::BLRA;
+  }
 
   if (!IsIndirect)
     return AArch64::TCRETURNdi;
 
-  // When BTI or PAuthLR are enabled, there are restrictions on using x16 and
-  // x17 to hold the function pointer.
+  // When BTI is enabled, we need to use TCRETURNriBTI to make sure that we use
+  // x16 or x17.
   if (FuncInfo->branchTargetEnforcement()) {
-    if (FuncInfo->branchProtectionPAuthLR())
+    if (PAI)
+      return AArch64::AUTH_TCRETURN_BTI;
+    else if (FuncInfo->branchProtectionPAuthLR())
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kovdan01 wrote:

Do not use else after return https://llvm.org/docs/CodingStandards.html#don-t-use-else-after-a-return

https://github.com/llvm/llvm-project/pull/85736