[llvm-branch-commits] [clang] [clang] Implement function pointer signing and authenticated function calls (PR #93906)

[Daniil Kovalev via llvm-branch-commits]

================
@@ -75,3 +93,36 @@ CodeGen::getConstantSignedPointer(CodeGenModule &CGM,
   return CGM.getConstantSignedPointer(pointer, key, storageAddress,
                                       otherDiscriminator);
 }
+
+/// If applicable, sign a given constant function pointer with the ABI rules for
+/// functionType.
+llvm::Constant *CodeGenModule::getFunctionPointer(llvm::Constant *pointer,
+                                                  QualType functionType,
+                                                  GlobalDecl GD) {
+  assert(functionType->isFunctionType() ||
+         functionType->isFunctionReferenceType() ||
+         functionType->isFunctionPointerType());
+
+  if (auto pointerAuth = getFunctionPointerAuthInfo(functionType)) {
+    return getConstantSignedPointer(
+      pointer, pointerAuth.getKey(), nullptr,
+      cast_or_null<llvm::Constant>(pointerAuth.getDiscriminator()));
+  }
+
+  return pointer;
+}
+
+llvm::Constant *CodeGenModule::getFunctionPointer(GlobalDecl GD,
+                                                  llvm::Type *Ty) {
+  const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
----------------
kovdan01 wrote:

nit

```suggestion
  const auto *FD = cast<FunctionDecl>(GD.getDecl());
```

https://github.com/llvm/llvm-project/pull/93906