[mlir][SparseTensor][NFC] Migrate to OpAsmAttrInterface for ASM alias generation (#130483)

After the introduction of `OpAsmAttrInterface`, it is favorable to
migrate code using `OpAsmDialectInterface` for ASM alias generation,
which lives in `Dialect.cpp`, to use `OpAsmAttrInterface`, which lives
in `Attrs.td`. In this way, attribute behavior is placed near its
tablegen definition and people won't need to go through other files to
know what other (unexpected) hooks comes into play.

Author: ZenithalHourlyRate

mlir/include/mlir/Dialect/SparseTensor/IR/SparseTensorAttrDefs.td

@@ -11,6 +11,7 @@
 
 include "mlir/IR/AttrTypeBase.td"
 include "mlir/IR/EnumAttr.td"
+include "mlir/IR/OpAsmInterface.td"
 include "mlir/Dialect/SparseTensor/IR/SparseTensorBase.td"
 include "mlir/IR/TensorEncoding.td"
 
@@ -112,7 +113,7 @@ def SparseTensorDimSliceAttr : SparseTensor_Attr<"SparseTensorDimSlice", []> {
 
 // Sparse tensor encoding attribute.
 def SparseTensorEncodingAttr : SparseTensor_Attr<"SparseTensorEncoding",
-         [ DeclareAttrInterfaceMethods<VerifiableTensorEncoding> ] > {
+         [ DeclareAttrInterfaceMethods<VerifiableTensorEncoding>, OpAsmAttrInterface ] > {
   let mnemonic = "encoding";
 
   let description = [{
@@ -543,6 +544,15 @@ def SparseTensorEncodingAttr : SparseTensor_Attr<"SparseTensorEncoding",
     void printSymbols(AffineMap &map, AsmPrinter &printer) const;
     void printDimensions(AffineMap &map, AsmPrinter &printer, ArrayRef<::mlir::sparse_tensor::SparseTensorDimSliceAttr> dimSlices) const;
     void printLevels(AffineMap &map, AsmPrinter &printer, ArrayRef<::mlir::sparse_tensor::LevelType> lvlTypes) const;
+
+    //
+    // OpAsmAttrInterface methods.
+    //
+
+    ::mlir::OpAsmAliasResult getAlias(::llvm::raw_ostream &os) const {
+      os << "sparse";
+      return ::mlir::OpAsmAliasResult::OverridableAlias;
+    }
   }];
 
   let genVerifyDecl = 1;

mlir/lib/Dialect/SparseTensor/IR/SparseTensorDialect.cpp

@@ -2778,22 +2778,7 @@ Operation *SparseTensorDialect::materializeConstant(OpBuilder &builder,
   return nullptr;
 }
 
-namespace {
-struct SparseTensorAsmDialectInterface : public OpAsmDialectInterface {
-  using OpAsmDialectInterface::OpAsmDialectInterface;
-
-  AliasResult getAlias(Attribute attr, raw_ostream &os) const override {
-    if (isa<SparseTensorEncodingAttr>(attr)) {
-      os << "sparse";
-      return AliasResult::OverridableAlias;
-    }
-    return AliasResult::NoAlias;
-  }
-};
-} // namespace
-
 void SparseTensorDialect::initialize() {
-  addInterface<SparseTensorAsmDialectInterface>();
   addAttributes<
 #define GET_ATTRDEF_LIST
 #include "mlir/Dialect/SparseTensor/IR/SparseTensorAttrDefs.cpp.inc"