[mlir][OpDSL] Add type function attributes.

Previously, OpDSL operation used hardcoded type conversion operations (cast or cast_unsigned). Supporting signed and unsigned casts thus meant implementing two different operations. Type function attributes allow us to define a single operation that has a cast type function attribute which at operation instantiation time may be set to cast or cast_unsigned. We may for example, defina a matmul operation with a cast argument:

```
@linalg_structured_op
def matmul(A=TensorDef(T1, S.M, S.K), B=TensorDef(T2, S.K, S.N), C=TensorDef(U, S.M, S.N, output=True),
    cast=TypeFnAttrDef(default=TypeFn.cast)):
  C[D.m, D.n] += cast(U, A[D.m, D.k]) * cast(U, B[D.k, D.n])
```

When instantiating the operation the attribute may be set to the desired cast function:

```
linalg.matmul(lhs, rhs, outs=[out], cast=TypeFn.cast_unsigned)
```

The revsion introduces a enum in the Linalg dialect that maps one-by-one to the type functions defined by OpDSL.

Reviewed By: aartbik

Differential Revision: https://reviews.llvm.org/D119718

mlir/include/mlir/Dialect/Linalg/IR/CMakeLists.txt

@@ -44,6 +44,18 @@ add_dependencies(mlir-headers LinalgOdsGen)
 
 add_mlir_dialect(LinalgOps linalg)
 
+set(LLVM_TARGET_DEFINITIONS LinalgOps.td)
+mlir_tablegen(LinalgOpsEnums.h.inc -gen-enum-decls)
+mlir_tablegen(LinalgOpsEnums.cpp.inc -gen-enum-defs)
+add_public_tablegen_target(MLIRLinalgOpsEnumsIncGen)
+add_dependencies(mlir-headers MLIRLinalgOpsEnumsIncGen)
+
+set(LLVM_TARGET_DEFINITIONS LinalgOps.td)
+mlir_tablegen(LinalgOpsAttrDefs.h.inc -gen-attrdef-decls)
+mlir_tablegen(LinalgOpsAttrDefs.cpp.inc -gen-attrdef-defs)
+add_public_tablegen_target(MLIRLinalgOpsAttributesIncGen)
+add_dependencies(mlir-headers MLIRLinalgOpsAttributesIncGen)
+
 add_mlir_doc(LinalgDoc LinalgOps Dialects/ -gen-op-doc)
 add_dependencies(LinalgOpsDocGen LinalgOdsGen)
 

mlir/include/mlir/Dialect/Linalg/IR/Linalg.h

@@ -104,6 +104,19 @@ LogicalResult verifyStructuredOpInterface(Operation *op);
 
 #include "mlir/Dialect/Linalg/IR/LinalgOpsDialect.h.inc"
 
+//===----------------------------------------------------------------------===//
+// Linalg Enums
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Linalg/IR/LinalgOpsEnums.h.inc"
+
+//===----------------------------------------------------------------------===//
+// Linalg Attributes
+//===----------------------------------------------------------------------===//
+
+#define GET_ATTRDEF_CLASSES
+#include "mlir/Dialect/Linalg/IR/LinalgOpsAttrDefs.h.inc"
+
 //===----------------------------------------------------------------------===//
 // Linalg Interfaces
 //===----------------------------------------------------------------------===//

mlir/include/mlir/Dialect/Linalg/IR/LinalgBase.td

@@ -13,6 +13,7 @@
 #ifndef LINALG_BASE
 #define LINALG_BASE
 
+include "mlir/IR/EnumAttr.td"
 include "mlir/IR/OpBase.td"
 
 def Linalg_Dialect : Dialect {
@@ -57,4 +58,17 @@ def Linalg_Dialect : Dialect {
   }];
 }
 
+// Define a TypeFn enum matching the OpDSL TypeFn class.
+def TypeFn : I32EnumAttr<"TypeFn", "", [
+  I32EnumAttrCase<"cast", 0>,
+  I32EnumAttrCase<"cast_unsigned", 1>
+]> {
+  let genSpecializedAttr = 0;
+  let cppNamespace = "::mlir::linalg";
+}
+
+def TypeFnAttr : EnumAttr<Linalg_Dialect, TypeFn, "type_fn"> {
+  let assemblyFormat = "`<` $value `>`";
+}
+
 #endif // LINALG_BASE