[llvm] [mlir] [MLIR] Add initial convert-memref-to-emitc pass (PR #85389)

[Marius Brehler via llvm-commits]

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@@ -0,0 +1,91 @@
+//===- 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/MemRefToEmitCPass.h"
+
+#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/PatternMatch.h"
+#include "mlir/Pass/Pass.h"
+#include "mlir/Transforms/DialectConversion.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>
+bool areLegal(RangeT &&range) {
+  return llvm::all_of(range, [](Type type) { return isLegal(type); });
+}
+
+bool isLegal(Operation *op) {
+  return areLegal(op->getOperandTypes()) && areLegal(op->getResultTypes());
+}
+
+bool isSignatureLegal(FunctionType ty) {
+  return areLegal(ty.getInputs()) && areLegal(ty.getResults());
+}
+
+struct ConvertMemRefToEmitCPass
+    : public impl::ConvertMemRefToEmitCBase<ConvertMemRefToEmitCPass> {
+  void runOnOperation() override {
+    TypeConverter converter;
+    // Fallback for other types.
+    converter.addConversion([](Type type) { return type; });
+    populateMemRefToEmitCTypeConversion(converter);
+    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);
+    populateFunctionOpInterfaceTypeConversionPattern<func::FuncOp>(patterns,
+                                                                   converter);
+    populateCallOpTypeConversionPattern(patterns, converter);
+    populateReturnOpTypeConversionPattern(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); });
----------------
marbre wrote:

First of all, I haven't really worked much with the TypeConverter yet.

The longer I think about this specific code, the more uncertain I am whether this part actually belongs here. I think, using the type converter could also be moved to the FuncToEmitC conversion. In consequence here, we would only convert MemRef ops. This would be fine as MemRef types don't belong to the MemRef dialect. I am kind of unsure how we want to compose this.

https://github.com/llvm/llvm-project/pull/85389