[mlir] Make extraClassOf compile with attribute and type interfaces

[zero9178]

Using extraClassOf currently does not work with attribute or type interfaces as the generated code calls getInterfaceFor, a private method of AttributeInterface and TypeInterface respectively.

This PR fixes this by applying the same change that has been done to OpInterface in the past: Make getInterfaceFor a protected member of the class, allowing the generated code in subclasses to use it.

An attribute and type interface with extraClassOf have been added as interfaces in the test dialect to ensure it compiles without errors.

[llvmbot]

@llvm/pr-subscribers-mlir-core

@llvm/pr-subscribers-mlir

Changes

Using `extraClassOf` currently does not work with attribute or type interfaces as the generated code calls `getInterfaceFor`, a private method of `AttributeInterface` and `TypeInterface` respectively.

This PR fixes this by applying the same change that has been done to OpInterface in the past: Make getInterfaceFor a protected member of the class, allowing the generated code in subclasses to use it.

An attribute and type interface with extraClassOf have been added as interfaces in the test dialect to ensure it compiles without errors.

Full diff: https://github.com/llvm/llvm-project/pull/66292.diff

3 Files Affected:

• (modified) mlir/include/mlir/IR/Attributes.h (+1-1)
• (modified) mlir/include/mlir/IR/Types.h (+1-1)
• (modified) mlir/test/lib/Dialect/Test/TestInterfaces.td (+26)

diff --git a/mlir/include/mlir/IR/Attributes.h b/mlir/include/mlir/IR/Attributes.h
index 53a2a1f2ad59f9e..ac5dd49f0ba3970 100644
--- a/mlir/include/mlir/IR/Attributes.h
+++ b/mlir/include/mlir/IR/Attributes.h
@@ -291,7 +291,7 @@ class AttributeInterface
                                           Attribute, AttributeTrait::TraitBase>;
   using InterfaceBase::InterfaceBase;
 
-private:
+protected:
   /// Returns the impl interface instance for the given type.
   static typename InterfaceBase::Concept *getInterfaceFor(Attribute attr) {
 #ifndef NDEBUG
diff --git a/mlir/include/mlir/IR/Types.h b/mlir/include/mlir/IR/Types.h
index 8443518027c0b62..832794928a44198 100644
--- a/mlir/include/mlir/IR/Types.h
+++ b/mlir/include/mlir/IR/Types.h
@@ -276,7 +276,7 @@ class TypeInterface : public detail::Interface<ConcreteType, Type, Traits, Type,
       detail::Interface<ConcreteType, Type, Traits, Type, TypeTrait::TraitBase>;
   using InterfaceBase::InterfaceBase;
 
-private:
+protected:
   /// Returns the impl interface instance for the given type.
   static typename InterfaceBase::Concept *getInterfaceFor(Type type) {
 #ifndef NDEBUG
diff --git a/mlir/test/lib/Dialect/Test/TestInterfaces.td b/mlir/test/lib/Dialect/Test/TestInterfaces.td
index e2ed27bdf0203e3..79a6c86493d418c 100644
--- a/mlir/test/lib/Dialect/Test/TestInterfaces.td
+++ b/mlir/test/lib/Dialect/Test/TestInterfaces.td
@@ -147,4 +147,30 @@ def TestOptionallyImplementedOpInterface
   }];
 }
 
+def TestOptionallyImplementedAttrInterface
+    : AttrInterface<"TestOptionallyImplementedAttrInterface"> {
+  let cppNamespace = "::mlir";
+
+  let methods = [
+    InterfaceMethod<"", "bool", "getImplementsInterface", (ins)>,
+  ];
+
+  let extraClassOf = [{
+    return $_attr.getImplementsInterface();
+  }];
+}
+
+def TestOptionallyImplementedTypeInterface
+    : TypeInterface<"TestOptionallyImplementedTypeInterface"> {
+  let cppNamespace = "::mlir";
+
+  let methods = [
+    InterfaceMethod<"", "bool", "getImplementsInterface", (ins)>,
+  ];
+
+  let extraClassOf = [{
+    return $_type.getImplementsInterface();
+  }];
+}
+
 #endif // MLIR_TEST_DIALECT_TEST_INTERFACES

[jpienaar]

Sounds reasonable and consistent with previous.