[Mlir-commits] [mlir] [MLIR][LLVM] Add bytecode support for several attributes (PR #162577)

[Bruno Cardoso Lopes]

================
@@ -0,0 +1,155 @@
+//===- LLVMDialectBytecode.cpp - LLVM Bytecode Implementation -------------===//
+//
+// 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 "LLVMDialectBytecode.h"
+#include "mlir/Bytecode/BytecodeImplementation.h"
+#include "mlir/Dialect/LLVMIR/LLVMAttrs.h"
+#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
+#include "mlir/Dialect/LLVMIR/LLVMTypes.h"
+#include "mlir/IR/Diagnostics.h"
+#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/TypeSwitch.h"
+#include <type_traits>
+
+using namespace mlir;
+using namespace mlir::LLVM;
+
+namespace {
+
+// Provide some forward declarations of the functions that will be generated by
+// the include below.
+static void write(DIExpressionElemAttr attribute,
+                  DialectBytecodeWriter &writer);
+static LogicalResult writeAttribute(Attribute attribute,
+                                    DialectBytecodeWriter &writer);
+
+//===--------------------------------------------------------------------===//
+// Optional ArrayRefs
+//
+// Note that both the writer and reader functions consider attributes to be
+// optional. This is because the attribute may be present by empty.
+//===--------------------------------------------------------------------===//
+
+template <class EntryTy>
+static void writeOptionalArrayRef(DialectBytecodeWriter &writer,
+                                  ArrayRef<EntryTy> storage) {
+  if (!storage.empty()) {
+    writer.writeOwnedBool(true);
+    writer.writeList(storage, [&](EntryTy val) {
+      if constexpr (std::is_base_of_v<Attribute, EntryTy>) {
+        (void)writer.writeOptionalAttribute(val);
+      } else if constexpr (std::is_integral_v<EntryTy>) {
+        (void)writer.writeVarInt(val);
+      } else
+        static_assert(true, "EntryTy not supported");
+    });
+  } else {
+    writer.writeOwnedBool(false);
+  }
+}
+
+template <class EntryTy>
+static LogicalResult readOptionalArrayRef(DialectBytecodeReader &reader,
+                                          SmallVectorImpl<EntryTy> &storage) {
+  bool isPresent = false;
+  if (failed(reader.readBool(isPresent)))
+    return failure();
+  // Nothing to do here, the array is empty.
----------------
bcardosolopes wrote:

The idea is for the caller to pass in a ArrayRef to the builder that refers to an empty `SmallVector`, there's nothing really to initialize here. This is what the callsite looks like:
```
  SmallVector<DINodeAttr> elements;
  if (... &&
      succeeded(readOptionalArrayRef<DINodeAttr>(reader, elements))) {
    return get<DICompositeTypeAttr>(..., elements);
```

https://github.com/llvm/llvm-project/pull/162577