Add support for writing binary ELF doc nodes

[tpr]

Summary

Will be used for a front-end compiler
https://github.com/GPUOpen-Drivers/llpc
to insert a binary blob value into AMDGPU PAL metadata.

Change-Id: I90685883d1478335937218e6b1a569b1b26dc05a

[scott.linder]

LGTM with 1 small nit

llvm/include/llvm/BinaryFormat/MsgPackDocument.h

380

Local should be CamelCase

llvm/include/llvm/BinaryFormat/MsgPackDocument.h

double getFloat() const {
     return Float;
   }
 
   StringRef getString() const {
     assert(getKind() == Type::String);
     return Raw;
   }
 
+  MemoryBufferRef getBinary() const {
+    assert(getKind() == Type::Binary);
+    return MemoryBufferRef(Raw, "");
+  }
+
   /// Get an ArrayDocNode for an array node. If Convert, convert the node to an
   /// array node if necessary.
   ArrayDocNode &getArray(bool Convert = false) {
     if (getKind() != Type::Array) {
       assert(Convert);
       convertToArray();
     }
     // This could be a static_cast, except ArrayDocNode is a forward reference.
public:
 
   /// Convenience assignment operators. This only works if the destination
   /// DocNode has an associated Document, i.e. it was not constructed using the
   /// default constructor. The string one does not copy, so the string must
   /// remain valid for the lifetime of the Document. Use fromString to avoid
   /// that restriction.
   DocNode &operator=(const char *Val) { return *this = StringRef(Val); }
   DocNode &operator=(StringRef Val);
+  DocNode &operator=(MemoryBufferRef Val);
   DocNode &operator=(bool Val);
   DocNode &operator=(int Val);
   DocNode &operator=(unsigned Val);
   DocNode &operator=(int64_t Val);
   DocNode &operator=(uint64_t Val);
 
 private:
   // Private constructor setting KindAndDoc, used by methods in Document.
public:
   }
 
   /// Create a String node associated with this Document. If !Copy, the passed
   /// string must remain valid for the lifetime of the Document.
   DocNode getNode(const char *V, bool Copy = false) {
     return getNode(StringRef(V), Copy);
   }
 
+  /// Create a Binary node associated with this Document. If !Copy, the passed
+  /// buffer must remain valid for the lifetime of the Document.
+  DocNode getNode(MemoryBufferRef V, bool Copy = false) {
+    auto Raw = V.getBuffer();
+    if (Copy)
+      Raw = addString(Raw);
+    auto N = DocNode(&KindAndDocs[size_t(Type::Binary)]);
+    N.Raw = Raw;
+    return N;
+  }
+
   /// Create an empty Map node associated with this Document.
   MapDocNode getMapNode() {
     auto N = DocNode(&KindAndDocs[size_t(Type::Map)]);
     Maps.push_back(std::unique_ptr<DocNode::MapTy>(new DocNode::MapTy));
     N.Map = Maps.back().get();
     return N.getMap();
   }
 

llvm/lib/BinaryFormat/MsgPackDocument.cpp

 // DocNode has an associated Document, i.e. it was not constructed using the
 // default constructor. The string one does not copy, so the string must
 // remain valid for the lifetime of the Document. Use fromString to avoid
 // that restriction.
 DocNode &DocNode::operator=(StringRef Val) {
   *this = getDocument()->getNode(Val);
   return *this;
 }
+DocNode &DocNode::operator=(MemoryBufferRef Val) {
+  *this = getDocument()->getNode(Val);
+  return *this;
+}
 DocNode &DocNode::operator=(bool Val) {
   *this = getDocument()->getNode(Val);
   return *this;
 }
 DocNode &DocNode::operator=(int Val) {
   *this = getDocument()->getNode(Val);
   return *this;
 }
case Type::Boolean:
       Node = getNode(Obj.Bool);
       break;
     case Type::Float:
       Node = getNode(Obj.Float);
       break;
     case Type::String:
       Node = getNode(Obj.Raw);
       break;
+    case Type::Binary:
+      Node = getNode(MemoryBufferRef(Obj.Raw, ""));
+      break;
     case Type::Map:
       Node = getMapNode();
       break;
     case Type::Array:
       Node = getArrayNode();
       break;
     default:
       return false; // Raw and Extension not supported
case Type::Int:
       MPWriter.write(Node.getInt());
       break;
     case Type::UInt:
       MPWriter.write(Node.getUInt());
       break;
     case Type::String:
       MPWriter.write(Node.getString());
       break;
+    case Type::Binary:
+      MPWriter.write(Node.getBinary());
+      break;
     case Type::Empty:
       llvm_unreachable("unhandled empty msgpack node");
     default:
       llvm_unreachable("unhandled msgpack object kind");
     }
     // Pop finished stack levels.
     while (!Stack.empty()) {
       if (Stack.back().Node.getKind() == Type::Map) {

llvm/unittests/BinaryFormat/MsgPackDocumentTest.cpp

 TEST(MsgPackDocument, TestReadInt) {
   Document Doc;
   bool Ok = Doc.readFromBlob(StringRef("\xd0\x00", 2), /*Multi=*/false);
   ASSERT_TRUE(Ok);
   ASSERT_EQ(Doc.getRoot().getKind(), Type::Int);
   ASSERT_EQ(Doc.getRoot().getInt(), 0);
 }
 
+TEST(MsgPackDocument, TestReadBinary) {
+  Document Doc;
+  uint8_t data[] = {1, 2, 3, 4};
+  bool Ok =
+      Doc.readFromBlob(StringRef("\xC4\x4\x1\x2\x3\x4", 6), /*Multi=*/false);
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(Doc.getRoot().getKind(), Type::Binary);
+  ASSERT_EQ(Doc.getRoot().getBinary().getBuffer(),
+            StringRef(reinterpret_cast<const char *>(data), 4));
+}
+
 TEST(MsgPackDocument, TestReadMergeArray) {
   Document Doc;
   bool Ok = Doc.readFromBlob(StringRef("\x92\xd0\x01\xc0"), /*Multi=*/false);
   ASSERT_TRUE(Ok);
   ASSERT_EQ(Doc.getRoot().getKind(), Type::Array);
   auto A = Doc.getRoot().getArray();
   ASSERT_EQ(A.size(), 2u);
   auto SI = A[0];

 TEST(MsgPackDocument, TestWriteInt) {
   Document Doc;
   Doc.getRoot() = 1;
   std::string Buffer;
   Doc.writeToBlob(Buffer);
   ASSERT_EQ(Buffer, "\x01");
 }
 
+TEST(MsgPackDocument, TestWriteBinary) {
+  uint8_t data[] = {1, 2, 3, 4};
+  Document Doc;
+  Doc.getRoot() = MemoryBufferRef(
+      StringRef(reinterpret_cast<const char *>(data), sizeof(data)), "");
+  std::string Buffer;
+  Doc.writeToBlob(Buffer);
+  ASSERT_EQ(Buffer, "\xC4\x4\x1\x2\x3\x4");
+}
+
 TEST(MsgPackDocument, TestWriteArray) {
   Document Doc;
   auto A = Doc.getRoot().getArray(/*Convert=*/true);
   A.push_back(Doc.getNode(int64_t(1)));
   A.push_back(Doc.getNode());
   std::string Buffer;
   Doc.writeToBlob(Buffer);
   ASSERT_EQ(Buffer, "\x92\x01\xc0");