[FXML-4440] Introduce a pass that annotates the type of the argument as an attribute (#167)

Create a pass that annotates all func op inputs with their type as attributes.

Author: josel-amd

mlir/include/mlir/Dialect/Func/Transforms/Passes.td

@@ -51,4 +51,15 @@ def DuplicateFunctionEliminationPass : Pass<"duplicate-function-elimination",
   let constructor = "mlir::func::createDuplicateFunctionEliminationPass()";
 }
 
+def AnnotateFunctionType: Pass<"annotate-function-type", "func::FuncOp"> {
+  let summary = "Annotate the function type as type attributes";
+  let description = [{
+    Annotates all the inputs and outputs of func.func operators with a type
+    attribute. The type attribute mirrors the actual type of the inputs/outputs.
+
+    This pass can be used to trace back the original types of func.func
+    operators in case they need to be modified.
+  }];
+}
+
 #endif // MLIR_DIALECT_FUNC_TRANSFORMS_PASSES_TD

mlir/lib/Dialect/Func/Transforms/AnnotateFunctionType.cpp

@@ -0,0 +1,47 @@
+//===- AnnotateInputTypes.cpp - Type attribute annotation for func ops ----===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a pass that creates type attributes for func parameters,
+// that mirror the actual type. This is useful when the func op input types
+// might change.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Func/Transforms/Passes.h"
+
+#include "mlir/Dialect/Func/IR/FuncOps.h"
+#include "mlir/IR/BuiltinAttributes.h"
+#include "mlir/Pass/Pass.h"
+
+using namespace mlir;
+
+namespace mlir::func {
+#define GEN_PASS_DEF_ANNOTATEFUNCTIONTYPE
+#include "mlir/Dialect/Func/Transforms/Passes.h.inc"
+} // namespace mlir::func
+
+namespace {
+struct AnnotateFunctionTypePass
+    : public mlir::func::impl::AnnotateFunctionTypeBase<
+          AnnotateFunctionTypePass> {
+
+  void runOnOperation() override {
+    func::FuncOp func = getOperation();
+    auto inputs = func.getArgumentTypes();
+    auto results = func.getResultTypes();
+
+    for (const auto [argNum, type] : llvm::enumerate(inputs)) {
+      func.setArgAttr(argNum, "func.orig_type", TypeAttr::get(type));
+    }
+
+    for (const auto [resultNum, type] : llvm::enumerate(results)) {
+      func.setResultAttr(resultNum, "func.orig_type", TypeAttr::get(type));
+    }
+  }
+};
+} // namespace

mlir/lib/Dialect/Func/Transforms/CMakeLists.txt

@@ -1,4 +1,5 @@
 add_mlir_dialect_library(MLIRFuncTransforms
+  AnnotateFunctionType.cpp
   DecomposeCallGraphTypes.cpp
   DuplicateFunctionElimination.cpp
   FuncBufferize.cpp

mlir/test/Dialect/Func/annotate-types.mlir

@@ -0,0 +1,27 @@
+// RUN: mlir-opt %s --split-input-file --annotate-function-type | FileCheck %s
+
+// CHECK-LABEL: func.func @one_arg(%arg0: tensor<f32> {func.orig_type = tensor<f32>}) -> (tensor<f32> {func.orig_type = tensor<f32>}) {
+func.func @one_arg(%arg0: tensor<f32>) -> tensor<f32> {
+  return %arg0 : tensor<f32>
+}
+
+// -----
+
+// CHECK-LABEL: func.func @one_arg_int(%arg0: tensor<ui8> {func.orig_type = tensor<ui8>}) -> (tensor<ui8> {func.orig_type = tensor<ui8>}) {
+func.func @one_arg_int(%arg0: tensor<ui8>) -> tensor<ui8> {
+  return %arg0 : tensor<ui8>
+}
+
+// -----
+
+// CHECK-LABEL: func.func @n_rank_tensor(%arg0: tensor<3x4x5xf32> {func.orig_type = tensor<3x4x5xf32>}) -> (tensor<3x4x5xf32> {func.orig_type = tensor<3x4x5xf32>}) {
+func.func @n_rank_tensor(%arg0: tensor<3x4x5xf32>) -> tensor<3x4x5xf32> {
+  return %arg0 : tensor<3x4x5xf32>
+}
+
+// -----
+
+// CHECK-LABEL: func.func @two_args(%arg0: f32 {func.orig_type = f32}, %arg1: f32 {func.orig_type = f32}) -> (f32 {func.orig_type = f32}) {
+func.func @two_args(%arg0: f32, %arg1: f32) -> f32 {
+  return %arg0 : f32
+}