[Mlir-commits] [mlir] [MLIR][LLVM] DI Expression Rewrite & Legalization (PR #77541)

[Tobias Gysi]

================
@@ -0,0 +1,61 @@
+//===- DIExpressionLegalization.cpp - DIExpression Legalization Patterns --===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/LLVMIR/Transforms/DIExpressionLegalization.h"
+
+#include "llvm/BinaryFormat/Dwarf.h"
+
+using namespace mlir;
+using namespace LLVM;
+
+//===----------------------------------------------------------------------===//
+// MergeFragments
+//===----------------------------------------------------------------------===//
+
+MergeFragments::OpIterT MergeFragments::match(OpIterRange operators) const {
+  OpIterT it = operators.begin();
+  if (it == operators.end() ||
+      it->getOpcode() != llvm::dwarf::DW_OP_LLVM_fragment)
+    return operators.begin();
+
+  ++it;
+  if (it == operators.end() ||
+      it->getOpcode() != llvm::dwarf::DW_OP_LLVM_fragment)
+    return operators.begin();
+
+  return ++it;
+}
+
+SmallVector<MergeFragments::OperatorT>
+MergeFragments::replace(OpIterRange operators) const {
+  OpIterT it = operators.begin();
+  OperatorT first = *(it++);
+  OperatorT second = *it;
+  // Add offsets & select the size of the earlier operator (the one closer to
+  // the IR value).
+  uint64_t offset = first.getArguments()[0] + second.getArguments()[0];
+  uint64_t size = first.getArguments()[1];
+  OperatorT newOp = OperatorT::get(
+      first.getContext(), llvm::dwarf::DW_OP_LLVM_fragment, {offset, size});
+  return SmallVector<OperatorT>{newOp};
+}
+
+//===----------------------------------------------------------------------===//
+// Runner
+//===----------------------------------------------------------------------===//
+
+void mlir::LLVM::legalizeDIExpressionsRecursively(Operation *op) {
+  LLVM::DIExpressionRewriter rewriter;
+  rewriter.addPattern(std::make_unique<MergeFragments>());
+
+  mlir::AttrTypeReplacer replacer;
----------------
gysit wrote:

```suggestion
  AttrTypeReplacer replacer;
```
ultra nit:

https://github.com/llvm/llvm-project/pull/77541