[clang] [llvm] [clang][llvm][AArch64] Set hardening fn attrs on synthetic functions (PR #211013)

[Anatoly Trosinenko via llvm-commits]

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@@ -1561,6 +1540,27 @@ void CodeGenModule::Release() {
                                 "sign-return-address-with-bkey", 2);
   }
   if (T.isAArch64()) {
+    // Emit the following 4 module flags so LLVM can derive corresponding
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atrosinenko wrote:

> And normally, we do not rely on checking "ptrauth-calls" in backend for indirect call signing - we just use ptrauth call bundles

Sure, my idea was that mid-end passes may need to synthesize functions with indirect calls - then they would need to know how to authenticate the pointers that are loaded from memory, if any. When I tried experimenting with something like that, I concluded that ad-hoc hardcoded constants might be easier to implement.

https://github.com/llvm/llvm-project/pull/211013