[MLIR] Add initial convert-memref-to-emitc pass (#30)

mlir/include/mlir/Conversion/MemRefToEmitC/MemRefToEmitC.h

@@ -0,0 +1,27 @@
+//===- MemRefToEmitC.h - Convert MemRef to EmitC --------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+#ifndef MLIR_CONVERSION_MEMREFTOEMITC_MEMREFTOEMITC_H
+#define MLIR_CONVERSION_MEMREFTOEMITC_MEMREFTOEMITC_H
+
+#include "mlir/Pass/Pass.h"
+
+namespace mlir {
+class RewritePatternSet;
+class TypeConverter;
+
+#define GEN_PASS_DECL_CONVERTMEMREFTOEMITC
+#include "mlir/Conversion/Passes.h.inc"
+
+void populateMemRefToEmitCConversionPatterns(RewritePatternSet &patterns,
+                                             TypeConverter &typeConverter);
+
+std::unique_ptr<OperationPass<>> createConvertMemRefToEmitCPass();
+
+} // namespace mlir
+
+#endif // MLIR_CONVERSION_MEMREFTOEMITC_MEMREFTOEMITC_H

mlir/include/mlir/Conversion/Passes.h

@@ -42,6 +42,7 @@
 #include "mlir/Conversion/MathToLLVM/MathToLLVM.h"
 #include "mlir/Conversion/MathToLibm/MathToLibm.h"
 #include "mlir/Conversion/MathToSPIRV/MathToSPIRVPass.h"
+#include "mlir/Conversion/MemRefToEmitC/MemRefToEmitC.h"
 #include "mlir/Conversion/MemRefToLLVM/MemRefToLLVM.h"
 #include "mlir/Conversion/MemRefToSPIRV/MemRefToSPIRVPass.h"
 #include "mlir/Conversion/NVGPUToNVVM/NVGPUToNVVM.h"

mlir/include/mlir/Conversion/Passes.td

@@ -724,6 +724,15 @@ def ConvertMathToFuncs : Pass<"convert-math-to-funcs", "ModuleOp"> {
   ];
 }
 
+//===----------------------------------------------------------------------===//
+// MemRefToEmitC
+//===----------------------------------------------------------------------===//
+
+def ConvertMemRefToEmitC : Pass<"convert-memref-to-emitc"> {
+  let summary = "Convert MemRef dialect to EmitC dialect";
+  let dependentDialects = ["emitc::EmitCDialect"];
+}
+
 //===----------------------------------------------------------------------===//
 // MemRefToLLVM
 //===----------------------------------------------------------------------===//

mlir/lib/Conversion/CMakeLists.txt

@@ -32,6 +32,7 @@ add_subdirectory(MathToFuncs)
 add_subdirectory(MathToLibm)
 add_subdirectory(MathToLLVM)
 add_subdirectory(MathToSPIRV)
+add_subdirectory(MemRefToEmitC)
 add_subdirectory(MemRefToLLVM)
 add_subdirectory(MemRefToSPIRV)
 add_subdirectory(NVGPUToNVVM)

mlir/lib/Conversion/MemRefToEmitC/CMakeLists.txt

@@ -0,0 +1,17 @@
+add_mlir_conversion_library(MLIRMemRefToEmitC
+  MemRefToEmitC.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${MLIR_MAIN_INCLUDE_DIR}/mlir/Conversion/MemRefToEmitC
+
+  DEPENDS
+  MLIRConversionPassIncGen
+
+  LINK_COMPONENTS
+  Core
+
+  LINK_LIBS PUBLIC
+  MLIREmitCDialect
+  MLIRMemRefDialect
+  MLIRTransforms
+  )

mlir/lib/Conversion/MemRefToEmitC/MemRefToEmitC.cpp

@@ -0,0 +1,113 @@
+//===- MemRefToEmitC.cpp - MemRef to EmitC conversion ---------------------===//
+//
+// 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 to convert memref ops into emitc ops.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Conversion/MemRefToEmitC/MemRefToEmitC.h"
+
+#include "mlir/Dialect/EmitC/IR/EmitC.h"
+#include "mlir/Dialect/Func/IR/FuncOps.h"
+#include "mlir/Dialect/Func/Transforms/FuncConversions.h"
+#include "mlir/Dialect/MemRef/IR/MemRef.h"
+#include "mlir/IR/Builders.h"
+#include "mlir/IR/BuiltinOps.h"
+#include "mlir/IR/IRMapping.h"
+#include "mlir/IR/MLIRContext.h"
+#include "mlir/IR/PatternMatch.h"
+#include "mlir/Interfaces/FunctionInterfaces.h"
+#include "mlir/Transforms/DialectConversion.h"
+#include "mlir/Transforms/Passes.h"
+
+namespace mlir {
+#define GEN_PASS_DEF_CONVERTMEMREFTOEMITC
+#include "mlir/Conversion/Passes.h.inc"
+} // namespace mlir
+
+using namespace mlir;
+
+namespace {
+
+/// Disallow all memrefs even though we only have conversions
+/// for memrefs with static shape right now to have good diagnostics.
+bool isLegal(Type t) { return !isa<BaseMemRefType>(t); }
+
+template <typename RangeT>
+std::enable_if_t<!std::is_convertible<RangeT, Type>::value &&
+                     !std::is_convertible<RangeT, Operation *>::value,
+                 bool>
+isLegal(RangeT &&range) {
+  return llvm::all_of(range, [](Type type) { return isLegal(type); });
+}
+
+bool isLegal(Operation *op) {
+  return isLegal(op->getOperandTypes()) && isLegal(op->getResultTypes());
+}
+
+bool isSignatureLegal(FunctionType ty) {
+  return isLegal(llvm::concat<const Type>(ty.getInputs(), ty.getResults()));
+}
+
+struct ConvertMemRefToEmitCPass
+    : public impl::ConvertMemRefToEmitCBase<ConvertMemRefToEmitCPass> {
+  void runOnOperation() override {
+    TypeConverter converter;
+    // Pass through for all other types.
+    converter.addConversion([](Type type) { return type; });
+
+    converter.addConversion([](MemRefType memRefType) -> std::optional<Type> {
+      if (memRefType.hasStaticShape()) {
+        return emitc::ArrayType::get(memRefType.getShape(),
+                                     memRefType.getElementType());
+      }
+      return {};
+    });
+
+    converter.addConversion(
+        [&converter](FunctionType ty) -> std::optional<Type> {
+          SmallVector<Type> inputs;
+          if (failed(converter.convertTypes(ty.getInputs(), inputs)))
+            return std::nullopt;
+
+          SmallVector<Type> results;
+          if (failed(converter.convertTypes(ty.getResults(), results)))
+            return std::nullopt;
+
+          return FunctionType::get(ty.getContext(), inputs, results);
+        });
+
+    RewritePatternSet patterns(&getContext());
+    populateMemRefToEmitCConversionPatterns(patterns, converter);
+
+    ConversionTarget target(getContext());
+    target.addDynamicallyLegalOp<func::FuncOp>(
+        [](func::FuncOp op) { return isSignatureLegal(op.getFunctionType()); });
+    target.addDynamicallyLegalDialect<func::FuncDialect>(
+        [](Operation *op) { return isLegal(op); });
+    target.addIllegalDialect<memref::MemRefDialect>();
+
+    if (failed(applyPartialConversion(getOperation(), target,
+                                      std::move(patterns))))
+      return signalPassFailure();
+  }
+};
+} // namespace
+
+void mlir::populateMemRefToEmitCConversionPatterns(RewritePatternSet &patterns,
+                                                   TypeConverter &converter) {
+
+  populateFunctionOpInterfaceTypeConversionPattern<func::FuncOp>(patterns,
+                                                                 converter);
+  populateCallOpTypeConversionPattern(patterns, converter);
+  populateReturnOpTypeConversionPattern(patterns, converter);
+}
+
+std::unique_ptr<OperationPass<>> mlir::createConvertMemRefToEmitCPass() {
+  return std::make_unique<ConvertMemRefToEmitCPass>();
+}

mlir/test/Conversion/MemRefToEmitC/memref-to-emit-failed.mlir

@@ -0,0 +1,24 @@
+// RUN: mlir-opt -convert-memref-to-emitc %s -split-input-file -verify-diagnostics
+
+// Unranked memrefs are not converted
+// expected-error@+1 {{failed to legalize operation 'func.func' that was explicitly marked illegal}}
+func.func @memref_unranked(%arg0 : memref<*xf32>) {
+  return
+}
+
+// -----
+
+// Memrefs with dynamic shapes are not converted
+// expected-error@+1 {{failed to legalize operation 'func.func' that was explicitly marked illegal}}
+func.func @memref_dynamic_shape(%arg0 : memref<2x?xf32>) {
+  return
+}
+
+// -----
+
+// Memrefs with dynamic shapes are not converted
+func.func @memref_op(%arg0 : memref<2x4xf32>) {
+  // expected-error@+1 {{failed to legalize operation 'memref.copy' that was explicitly marked illegal}}
+  memref.copy %arg0, %arg0 : memref<2x4xf32> to memref<2x4xf32>
+  return
+}

mlir/test/Conversion/MemRefToEmitC/memref-to-emitc.mlir

@@ -0,0 +1,24 @@
+// RUN: mlir-opt -convert-memref-to-emitc %s -split-input-file | FileCheck %s
+
+// CHECK-LABEL: memref_arg
+// CHECK-SAME:  !emitc.array<32xf32>)
+func.func @memref_arg(%arg0 : memref<32xf32>) {
+  func.return
+}
+
+// -----
+
+// CHECK-LABEL: memref_return
+// CHECK-SAME:  %[[arg0:.*]]: !emitc.array<32xf32>) -> !emitc.array<32xf32>
+func.func @memref_return(%arg0 : memref<32xf32>) -> memref<32xf32> {
+// CHECK: return %[[arg0]] : !emitc.array<32xf32>
+  func.return %arg0 : memref<32xf32>
+}
+
+// CHECK-LABEL: memref_call
+// CHECK-SAME:  %[[arg0:.*]]: !emitc.array<32xf32>)
+func.func @memref_call(%arg0 : memref<32xf32>) {
+// CHECK: call @memref_return(%[[arg0]]) : (!emitc.array<32xf32>) -> !emitc.array<32xf32>
+  func.call @memref_return(%arg0) : (memref<32xf32>) -> memref<32xf32>
+  func.return
+}