[mlir] Add elementAttr to TypedArrayAttrBase.

In code generators, one can automate the translation of typed ArrayAttrs
if element attribute translators are already implemented. However, the
type of the element attribute is lost at the construction of
TypedArrayAttrBase. With this change one can inspect the element type
and generate the translation logic automatically, which will reduce the
code repetition.

Differential Revision: https://reviews.llvm.org/D73579

mlir/include/mlir/IR/OpBase.td

@@ -1130,6 +1130,8 @@ class TypedArrayAttrBase<Attr element, string description>: ArrayAttrBase<
                           "; })">]>,
     description> {
   let constBuilderCall = "$_builder.getArrayAttr($0)";
+
+  Attr elementAttr = element;
 }
 
 def I32ArrayAttr : TypedArrayAttrBase<I32Attr,

mlir/test/mlir-tblgen/op-attribute.td

@@ -1,5 +1,6 @@
 // RUN: mlir-tblgen -gen-op-decls -I %S/../../include %s | FileCheck %s --check-prefix=DECL --dump-input-on-failure
 // RUN: mlir-tblgen -gen-op-defs -I %S/../../include %s | FileCheck %s --check-prefix=DEF --dump-input-on-failure
+// RUN: mlir-tblgen -print-records -I %S/../../include %s | FileCheck %s --check-prefix=RECORD --dump-input-on-failure
 
 include "mlir/IR/OpBase.td"
 
@@ -239,3 +240,12 @@ def UnitAttrOp : NS_Op<"unit_attr_op", []> {
 // DEF:   return {{.*}} != nullptr
 
 // DEF: build(Builder *odsBuilder, OperationState &odsState, /*optional*/UnitAttr attr)
+
+
+// Test elementAttr field of TypedArrayAttr.
+// ---
+
+def SomeTypedArrayAttr : TypedArrayAttrBase<SomeAttr, "SomeAttr array">;
+
+// RECORD-LABEL: def SomeTypedArrayAttr
+// RECORD: Attr elementAttr = SomeAttr;