[clang] [Clang] FunctionEffects: Correctly navigate through array types in FunctionEffectsRef::get(). (PR #121525)

[Doug Wyatt via cfe-commits]

================
@@ -8836,13 +8836,22 @@ void FixedPointValueToString(SmallVectorImpl<char> &Str, llvm::APSInt Val,
                              unsigned Scale);
 
 inline FunctionEffectsRef FunctionEffectsRef::get(QualType QT) {
+  const Type *TypePtr = QT.getTypePtr();
   while (true) {
-    QualType Pointee = QT->getPointeeType();
-    if (Pointee.isNull())
+    // Note that getPointeeType() seems to successfully navigate some constructs
+    // for which isAnyPointerType() returns false (e.g.
+    // pointer-to-member-function).
+    QualType Pointee = TypePtr->getPointeeType();
+    if (Pointee.isNull()) {
+      if (TypePtr->isArrayType()) {
+        TypePtr = TypePtr->getBaseElementTypeUnsafe();
+        continue;
+      }
       break;
-    QT = Pointee;
+    }
+    TypePtr = Pointee.getTypePtr();
   }
-  if (const auto *FPT = QT->getAs<FunctionProtoType>())
+  if (const auto *FPT = TypePtr->getAs<FunctionProtoType>())
----------------
dougsonos wrote:

Yeah I really wanted to use that! When I tried, I discovered that it uses isAnyPointerType() which fails for PTMF (as commented above).

```
inline const Type *Type::getPointeeOrArrayElementType() const {
  const Type *type = this;
  if (type->isAnyPointerType())
    return type->getPointeeType().getTypePtr();
  else if (type->isArrayType())
    return type->getBaseElementTypeUnsafe();
  return type;
}
```

https://github.com/llvm/llvm-project/pull/121525