[NFC][ARM][AArch64] Deduplicated code. (#82785)

Add the SignReturnAddressScopeKind to the BranchProtectionInfo class.

Author: DanielKristofKiss

clang/include/clang/Basic/TargetInfo.h

@@ -1369,13 +1369,35 @@ class TargetInfo : public TransferrableTargetInfo,
   }
 
   struct BranchProtectionInfo {
-    LangOptions::SignReturnAddressScopeKind SignReturnAddr =
-        LangOptions::SignReturnAddressScopeKind::None;
-    LangOptions::SignReturnAddressKeyKind SignKey =
-        LangOptions::SignReturnAddressKeyKind::AKey;
-    bool BranchTargetEnforcement = false;
-    bool BranchProtectionPAuthLR = false;
-    bool GuardedControlStack = false;
+    LangOptions::SignReturnAddressScopeKind SignReturnAddr;
+    LangOptions::SignReturnAddressKeyKind SignKey;
+    bool BranchTargetEnforcement;
+    bool BranchProtectionPAuthLR;
+    bool GuardedControlStack;
+
+    BranchProtectionInfo() = default;
+
+    const char *getSignReturnAddrStr() const {
+      switch (SignReturnAddr) {
+      case LangOptions::SignReturnAddressScopeKind::None:
+        return "none";
+      case LangOptions::SignReturnAddressScopeKind::NonLeaf:
+        return "non-leaf";
+      case LangOptions::SignReturnAddressScopeKind::All:
+        return "all";
+      }
+      assert(false && "Unexpected SignReturnAddressScopeKind");
+    }
+
+    const char *getSignKeyStr() const {
+      switch (SignKey) {
+      case LangOptions::SignReturnAddressKeyKind::AKey:
+        return "a_key";
+      case LangOptions::SignReturnAddressKeyKind::BKey:
+        return "b_key";
+      }
+      assert(false && "Unexpected SignReturnAddressKeyKind");
+    }
   };
 
   /// Determine if the Architecture in this TargetInfo supports branch

clang/lib/CodeGen/Targets/AArch64.cpp

@@ -132,8 +132,7 @@ class AArch64TargetCodeGenInfo : public TargetCodeGenInfo {
     assert(Error.empty());
 
     auto *Fn = cast<llvm::Function>(GV);
-    static const char *SignReturnAddrStr[] = {"none", "non-leaf", "all"};
-    Fn->addFnAttr("sign-return-address", SignReturnAddrStr[static_cast<int>(BPI.SignReturnAddr)]);
+    Fn->addFnAttr("sign-return-address", BPI.getSignReturnAddrStr());
 
     if (BPI.SignReturnAddr != LangOptions::SignReturnAddressScopeKind::None) {
       Fn->addFnAttr("sign-return-address-key",

clang/lib/CodeGen/Targets/ARM.cpp

@@ -152,13 +152,7 @@ class ARMTargetCodeGenInfo : public TargetCodeGenInfo {
               diag::warn_target_unsupported_branch_protection_attribute)
               << Arch;
         } else {
-          static const char *SignReturnAddrStr[] = {"none", "non-leaf", "all"};
-          assert(static_cast<unsigned>(BPI.SignReturnAddr) <= 2 &&
-                 "Unexpected SignReturnAddressScopeKind");
-          Fn->addFnAttr(
-              "sign-return-address",
-              SignReturnAddrStr[static_cast<int>(BPI.SignReturnAddr)]);
-
+          Fn->addFnAttr("sign-return-address", BPI.getSignReturnAddrStr());
           Fn->addFnAttr("branch-target-enforcement",
                         BPI.BranchTargetEnforcement ? "true" : "false");
         }