[clang] [clang][ptrauth] Add support for querying the ptrauth schema of a type (PR #138482)

[Oliver Hunt via cfe-commits]

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@@ -9619,6 +9620,65 @@ ObjCInterfaceDecl *ASTContext::getObjCProtocolDecl() const {
   return ObjCProtocolClassDecl;
 }
 
+std::optional<PointerAuthQualifier>
+ASTContext::getExplicitOrImplicitPointerAuth(QualType T) {
+  auto ExplicitQualifier = T.getPointerAuth();
+  if (ExplicitQualifier.isPresent())
+    return ExplicitQualifier;
+  if (T->isDependentType()) {
+    return std::nullopt;
+  }
+  // FIXME: The more we expand pointer auth support, the more it becomes clear
+  // the codegen option's PointerAuth info belongs in LangOpts
+  if (!LangOpts.PointerAuthCalls)
+    return PointerAuthQualifier();
+  if (T->isFunctionPointerType() || T->isFunctionReferenceType())
+    T = T->getPointeeType();
+  if (!T->isFunctionType())
+    return PointerAuthQualifier();
+  int ExtraDiscriminator = 0;
+  if (LangOpts.PointerAuthFunctionTypeDiscrimination) {
+    ExtraDiscriminator = getPointerAuthTypeDiscriminator(T);
+  }
+  return PointerAuthQualifier::Create(
+      LangOpts.PointerAuthFunctionKey, false, ExtraDiscriminator,
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ojhunt wrote:

Yup (another "I wonder if we can make clang-tidy complain")

https://github.com/llvm/llvm-project/pull/138482