[llvm] [CGData] Outlined Hash Tree (PR #89792)

[Guillaume Belz via llvm-commits]

================
@@ -0,0 +1,168 @@
+//===-- OutlinedHashTreeRecord.cpp ----------------------------------------===//
+//
+// 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 defines the OutlinedHashTreeRecord class. This class holds the outlined
+// hash tree for both serialization and deserialization processes. It utilizes
+// two data formats for serialization: raw binary data and YAML.
+// These two formats can be used interchangeably.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGenData/OutlinedHashTreeRecord.h"
+#include "llvm/ObjectYAML/YAML.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/EndianStream.h"
+
+#define DEBUG_TYPE "outlined-hash-tree"
+
+using namespace llvm;
+using namespace llvm::support;
+
+namespace llvm {
+namespace yaml {
+
+template <> struct MappingTraits<HashNodeStable> {
+  static void mapping(IO &io, HashNodeStable &res) {
+    io.mapRequired("Hash", res.Hash);
+    io.mapRequired("Terminals", res.Terminals);
+    io.mapRequired("SuccessorIds", res.SuccessorIds);
+  }
+};
+
+template <> struct CustomMappingTraits<IdHashNodeStableMapTy> {
+  static void inputOne(IO &io, StringRef Key, IdHashNodeStableMapTy &V) {
+    HashNodeStable NodeStable;
+    io.mapRequired(Key.str().c_str(), NodeStable);
+    unsigned Id;
+    if (Key.getAsInteger(0, Id)) {
+      io.setError("Id not an integer");
+      return;
+    }
+    V.insert({Id, NodeStable});
+  }
+
+  static void output(IO &io, IdHashNodeStableMapTy &V) {
+    for (auto Iter = V.begin(); Iter != V.end(); ++Iter)
+      io.mapRequired(utostr(Iter->first).c_str(), Iter->second);
+  }
+};
+
+} // namespace yaml
+} // namespace llvm
+
+void OutlinedHashTreeRecord::serialize(raw_ostream &OS) const {
+  IdHashNodeStableMapTy IdNodeStableMap;
+  convertToStableData(IdNodeStableMap);
+  support::endian::Writer Writer(OS, endianness::little);
+  Writer.write<uint32_t>(IdNodeStableMap.size());
+
+  for (const auto &[Id, NodeStable] : IdNodeStableMap) {
+    Writer.write<uint32_t>(Id);
+    Writer.write<uint64_t>(NodeStable.Hash);
+    Writer.write<uint32_t>(NodeStable.Terminals);
+    Writer.write<uint32_t>(NodeStable.SuccessorIds.size());
+    for (auto SuccessorId : NodeStable.SuccessorIds)
+      Writer.write<uint32_t>(SuccessorId);
+  }
+}
+
+void OutlinedHashTreeRecord::deserialize(const unsigned char *&Ptr) {
+  IdHashNodeStableMapTy IdNodeStableMap;
+  auto NumIdNodeStableMap =
+      endian::readNext<uint32_t, endianness::little, unaligned>(Ptr);
+
+  for (unsigned I = 0; I < NumIdNodeStableMap; ++I) {
+    auto Id = endian::readNext<uint32_t, endianness::little, unaligned>(Ptr);
+    HashNodeStable NodeStable;
+    NodeStable.Hash =
+        endian::readNext<uint64_t, endianness::little, unaligned>(Ptr);
+    NodeStable.Terminals =
+        endian::readNext<uint32_t, endianness::little, unaligned>(Ptr);
+    auto NumSuccessorIds =
+        endian::readNext<uint32_t, endianness::little, unaligned>(Ptr);
+    for (unsigned J = 0; J < NumSuccessorIds; ++J)
+      NodeStable.SuccessorIds.push_back(
+          endian::readNext<uint32_t, endianness::little, unaligned>(Ptr));
+
+    IdNodeStableMap[Id] = std::move(NodeStable);
+  }
+
+  convertFromStableData(IdNodeStableMap);
+}
+
+void OutlinedHashTreeRecord::serializeYAML(yaml::Output &YOS) const {
+  IdHashNodeStableMapTy IdNodeStableMap;
+  convertToStableData(IdNodeStableMap);
+
+  YOS << IdNodeStableMap;
+}
+
+void OutlinedHashTreeRecord::deserializeYAML(yaml::Input &YIS) {
+  IdHashNodeStableMapTy IdNodeStableMap;
+
+  YIS >> IdNodeStableMap;
+  YIS.nextDocument();
+
+  convertFromStableData(IdNodeStableMap);
+}
+
+void OutlinedHashTreeRecord::convertToStableData(
+    IdHashNodeStableMapTy &IdNodeStableMap) const {
+  // Build NodeIdMap
+  HashNodeIdMapTy NodeIdMap;
+  HashTree->walkGraph(
+      [&NodeIdMap](const HashNode *Current) {
+        size_t Index = NodeIdMap.size();
+        NodeIdMap[Current] = Index;
+        assert(Index = NodeIdMap.size() + 1 &&
----------------
GuillaumeBelz wrote:

@kyulee-com  This line looks suspicious and generates a warning:

```
llvm/lib/CodeGenData/OutlinedHashTreeRecord.cpp:122:22: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  122 |         assert(Index = NodeIdMap.size() + 1 &&
      |                ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
  123 |                        "Expected size of NodeMap to increment by 1");
      |                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```

https://github.com/llvm/llvm-project/pull/89792