[llvm] [LLVM] Refactor Autoupgrade function attributes from Module attributes. (PR #84494)

[Daniel Hoekwater via llvm-commits]

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@@ -5182,65 +5182,46 @@ void llvm::UpgradeFunctionAttributes(Function &F) {
 static bool isModuleAttributeSet(Module &M, const StringRef &ModAttr) {
   const auto *Attr =
       mdconst::extract_or_null<ConstantInt>(M.getModuleFlag(ModAttr));
-  return Attr && Attr->getZExtValue();
+  return Attr && Attr->isOne();
 }
 
-// Copy an attribute from module to the function if exists.
-// First value of the pair is used when the module attribute is not zero
-// the second otherwise.
-static void
-CopyModuleAttributeToFunction(Function &F, StringRef FnAttrName,
-                              StringRef ModAttrName,
-                              std::pair<StringRef, StringRef> Values) {
-  if (F.hasFnAttribute(FnAttrName))
-    return;
-  F.addFnAttr(FnAttrName, isModuleAttributeSet(*F.getParent(), ModAttrName)
-                              ? Values.first
-                              : Values.second);
-}
-
-// Copy a boolean attribute from module to the function if exists.
-// Module attribute treated false if zero otherwise true.
-static void CopyModuleAttributeToFunction(Function &F, StringRef AttrName) {
-  CopyModuleAttributeToFunction(
-      F, AttrName, AttrName,
-      std::make_pair<StringRef, StringRef>("true", "false"));
-}
-
-// Copy an attribute from module to the function if exists.
-// First value of the pair is used when the module attribute is not zero
-// the second otherwise.
-static void
-CopyModuleAttributeToFunction(Function &F, StringRef AttrName,
-                              std::pair<StringRef, StringRef> Values) {
-  CopyModuleAttributeToFunction(F, AttrName, AttrName, Values);
+// Check if the function attribute is not present and set it.
+static void SetFunctionAttrIfNotSet(Function &F, StringRef FnAttrName,
+                                    StringRef Value) {
+  if (!F.hasFnAttribute(FnAttrName))
+    F.addFnAttr(FnAttrName, Value);
 }
 
 void llvm::CopyModuleAttrToFunctions(Module &M) {
   Triple T(M.getTargetTriple());
   if (!T.isThumb() && !T.isARM() && !T.isAArch64())
     return;
 
+  StringRef SignTypeValue = "none";
----------------
dhoekwater wrote:

Since adding the `sign-return-address=none` attribute is not a noop (it should not be set if pac and bti are disabled), is there something we can predicate adding this attribute on? For example, is `sign-return-address` only set when `sign-return-address-with-bkey` is non-null for the module?

https://github.com/llvm/llvm-project/pull/84494