[PDB] Add tests for BinaryStream.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296555 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 644 insertions, 0 deletions

diff --git a/unittests/DebugInfo/PDB/BinaryStreamTest.cpp b/unittests/DebugInfo/PDB/BinaryStreamTest.cpp
new file mode 100644
index 00000000000..04561987506
--- /dev/null
+++ b/unittests/DebugInfo/PDB/BinaryStreamTest.cpp
@@ -0,0 +1,643 @@
+//===- llvm/unittest/Support/BinaryStreamTest.cpp -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/MSF/BinaryByteStream.h"
+#include "llvm/DebugInfo/MSF/BinaryItemStream.h"
+#include "llvm/DebugInfo/MSF/BinaryStreamArray.h"
+#include "llvm/DebugInfo/MSF/BinaryStreamReader.h"
+#include "llvm/DebugInfo/MSF/BinaryStreamRef.h"
+#include "llvm/DebugInfo/MSF/BinaryStreamWriter.h"
+#include "gtest/gtest.h"
+
+#include <unordered_map>
+
+using namespace llvm;
+using namespace llvm::support;
+
+#define EXPECT_NO_ERROR(Err)                                                   \
+  {                                                                            \
+    auto E = Err;                                                              \
+    EXPECT_FALSE(static_cast<bool>(E));                                        \
+    if (E)                                                                     \
+      consumeError(std::move(E));                                              \
+  }
+
+#define ASSERT_NO_ERROR(Err)                                                   \
+  {                                                                            \
+    auto E = Err;                                                              \
+    ASSERT_FALSE(static_cast<bool>(E));                                        \
+    if (E)                                                                     \
+      consumeError(std::move(E));                                              \
+  }
+
+#define EXPECT_ERROR(Err)                                                      \
+  {                                                                            \
+    auto E = Err;                                                              \
+    EXPECT_TRUE(static_cast<bool>(E));                                         \
+    if (E)                                                                     \
+      consumeError(std::move(E));                                              \
+  }
+
+namespace {
+
+class DiscontiguousStream : public WritableBinaryStream {
+public:
+  DiscontiguousStream(MutableArrayRef<uint8_t> Data, endianness Endian)
+      : Data(Data), PartitionIndex(Data.size() / 2), Endian(Endian) {}
+
+  endianness getEndian() const override { return Endian; }
+
+  Error readBytes(uint32_t Offset, uint32_t Size,
+                  ArrayRef<uint8_t> &Buffer) override {
+    if (Offset + Size > Data.size())
+      return errorCodeToError(make_error_code(std::errc::no_buffer_space));
+    uint32_t S = startIndex(Offset);
+    auto Ref = Data.drop_front(S);
+    if (Ref.size() >= Size) {
+      Buffer = Ref.take_front(Size);
+      return Error::success();
+    }
+
+    uint32_t BytesLeft = Size - Ref.size();
+    uint8_t *Ptr = Allocator.Allocate<uint8_t>(Size);
+    ::memcpy(Ptr, Ref.data(), Ref.size());
+    ::memcpy(Ptr + Ref.size(), Data.data(), BytesLeft);
+    Buffer = makeArrayRef<uint8_t>(Ptr, Size);
+    return Error::success();
+  }
+
+  Error readLongestContiguousChunk(uint32_t Offset,
+                                   ArrayRef<uint8_t> &Buffer) override {
+    if (Offset >= Data.size())
+      return errorCodeToError(make_error_code(std::errc::no_buffer_space));
+    uint32_t S = startIndex(Offset);
+    Buffer = Data.drop_front(S);
+    return Error::success();
+  }
+
+  uint32_t getLength() override { return Data.size(); }
+
+  Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> SrcData) override {
+    if (Offset + SrcData.size() > Data.size())
+      return errorCodeToError(make_error_code(std::errc::no_buffer_space));
+    if (SrcData.empty())
+      return Error::success();
+
+    uint32_t S = startIndex(Offset);
+    MutableArrayRef<uint8_t> Ref(Data);
+    Ref = Ref.drop_front(S);
+    if (Ref.size() >= SrcData.size()) {
+      ::memcpy(Ref.data(), SrcData.data(), SrcData.size());
+      return Error::success();
+    }
+
+    uint32_t BytesLeft = SrcData.size() - Ref.size();
+    ::memcpy(Ref.data(), SrcData.data(), Ref.size());
+    ::memcpy(&Data[0], SrcData.data() + Ref.size(), BytesLeft);
+    return Error::success();
+  }
+  Error commit() override { return Error::success(); }
+
+private:
+  uint32_t startIndex(uint32_t Offset) const {
+    return (Offset + PartitionIndex) % Data.size();
+  }
+
+  uint32_t endIndex(uint32_t Offset, uint32_t Size) const {
+    return (startIndex(Offset) + Size - 1) % Data.size();
+  }
+
+  // Buffer is organized like this:
+  // -------------------------------------------------
+  // | N/2 | N/2+1 | ... | N-1 | 0 | 1 | ... | N-2-1 |
+  // -------------------------------------------------
+  // So reads from the beginning actually come from the middle.
+  MutableArrayRef<uint8_t> Data;
+  uint32_t PartitionIndex = 0;
+  endianness Endian;
+  BumpPtrAllocator Allocator;
+};
+
+class BinaryStreamTest : public testing::Test {
+  static constexpr endianness Endians[] = {big, little, native};
+  static constexpr uint32_t NumEndians = llvm::array_lengthof(Endians);
+  static constexpr uint32_t NumStreams = 2 * NumEndians;
+
+public:
+  BinaryStreamTest() {}
+
+  void SetUp() override {
+    Streams.clear();
+    Streams.resize(NumStreams);
+    InputData.clear();
+    OutputData.clear();
+  }
+
+protected:
+  struct StreamPair {
+    std::unique_ptr<BinaryStream> Input;
+    std::unique_ptr<WritableBinaryStream> Output;
+  };
+
+  void initializeInput(ArrayRef<uint8_t> Input) {
+    InputData = Input;
+
+    BrokenInputData.resize(InputData.size());
+    if (!Input.empty()) {
+      uint32_t PartitionIndex = InputData.size() / 2;
+      uint32_t RightBytes = InputData.size() - PartitionIndex;
+      uint32_t LeftBytes = PartitionIndex;
+      if (RightBytes > 0)
+        ::memcpy(&BrokenInputData[PartitionIndex], Input.data(), RightBytes);
+      if (LeftBytes > 0)
+        ::memcpy(&BrokenInputData[0], Input.data() + RightBytes, LeftBytes);
+    }
+
+    for (uint32_t I = 0; I < NumEndians; ++I) {
+      auto InByteStream =
+          llvm::make_unique<BinaryByteStream>(InputData, Endians[I]);
+      auto InBrokenStream =
+          llvm::make_unique<DiscontiguousStream>(BrokenInputData, Endians[I]);
+
+      Streams[I * 2].Input = std::move(InByteStream);
+      Streams[I * 2 + 1].Input = std::move(InBrokenStream);
+    }
+  }
+
+  void initializeOutput(uint32_t Size) {
+    OutputData.resize(Size);
+    BrokenOutputData.resize(Size);
+
+    for (uint32_t I = 0; I < NumEndians; ++I) {
+      Streams[I * 2].Output =
+          llvm::make_unique<MutableBinaryByteStream>(OutputData, Endians[I]);
+      Streams[I * 2 + 1].Output =
+          llvm::make_unique<DiscontiguousStream>(BrokenOutputData, Endians[I]);
+    }
+  }
+
+  void initializeOutputFromInput() {
+    for (uint32_t I = 0; I < NumEndians; ++I) {
+      Streams[I * 2].Output =
+          llvm::make_unique<MutableBinaryByteStream>(InputData, Endians[I]);
+      Streams[I * 2 + 1].Output =
+          llvm::make_unique<DiscontiguousStream>(BrokenInputData, Endians[I]);
+    }
+  }
+
+  void initializeInputFromOutput() {
+    for (uint32_t I = 0; I < NumEndians; ++I) {
+      Streams[I * 2].Input =
+          llvm::make_unique<BinaryByteStream>(OutputData, Endians[I]);
+      Streams[I * 2 + 1].Input =
+          llvm::make_unique<DiscontiguousStream>(BrokenOutputData, Endians[I]);
+    }
+  }
+
+  std::vector<uint8_t> InputData;
+  std::vector<uint8_t> BrokenInputData;
+
+  std::vector<uint8_t> OutputData;
+  std::vector<uint8_t> BrokenOutputData;
+
+  std::vector<StreamPair> Streams;
+};
+
+// Tests that a we can read from a BinaryByteStream without a StreamReader.
+TEST_F(BinaryStreamTest, BinaryByteStreamProperties) {
+  std::vector<uint8_t> InputData = {1, 2, 3, 4, 5};
+  initializeInput(InputData);
+
+  for (auto &Stream : Streams) {
+    ArrayRef<uint8_t> Buffer;
+
+    // 1. If the read fits it should work.
+    ASSERT_EQ(InputData.size(), Stream.Input->getLength());
+    ASSERT_NO_ERROR(Stream.Input->readBytes(2, 1, Buffer));
+    EXPECT_EQ(makeArrayRef(InputData).slice(2, 1), Buffer);
+    ASSERT_NO_ERROR(Stream.Input->readBytes(0, 4, Buffer));
+    EXPECT_EQ(makeArrayRef(InputData).slice(0, 4), Buffer);
+
+    // 2. Reading past the bounds of the input should fail.
+    EXPECT_ERROR(Stream.Input->readBytes(4, 2, Buffer));
+  }
+}
+
+// Test that we can write to a BinaryStream without a StreamWriter.
+TEST_F(BinaryStreamTest, MutableBinaryByteStreamProperties) {
+  std::vector<uint8_t> InputData = {'T', 'e', 's', 't', '\0'};
+  initializeInput(InputData);
+  initializeOutput(InputData.size());
+
+  // For every combination of input stream and output stream.
+  for (auto &Stream : Streams) {
+    MutableArrayRef<uint8_t> Buffer;
+    ASSERT_EQ(InputData.size(), Stream.Input->getLength());
+
+    // 1. Try two reads that are supposed to work.  One from offset 0, and one
+    // from the middle.
+    uint32_t Offsets[] = {0, 3};
+    for (auto Offset : Offsets) {
+      uint32_t ExpectedSize = Stream.Input->getLength() - Offset;
+
+      // Read everything from Offset until the end of the input data.
+      ArrayRef<uint8_t> Data;
+      ASSERT_NO_ERROR(Stream.Input->readBytes(Offset, ExpectedSize, Data));
+      ASSERT_EQ(ExpectedSize, Data.size());
+
+      // Then write it to the destination.
+      ASSERT_NO_ERROR(Stream.Output->writeBytes(0, Data));
+
+      // Then we read back what we wrote, it should match the corresponding
+      // slice of the original input data.
+      ArrayRef<uint8_t> Data2;
+      ASSERT_NO_ERROR(Stream.Output->readBytes(Offset, ExpectedSize, Data2));
+      EXPECT_EQ(makeArrayRef(InputData).drop_front(Offset), Data2);
+    }
+
+    std::vector<uint8_t> BigData = {0, 1, 2, 3, 4};
+    // 2. If the write is too big, it should fail.
+    EXPECT_ERROR(Stream.Output->writeBytes(3, BigData));
+  }
+}
+
+// Test that FixedStreamArray works correctly.
+TEST_F(BinaryStreamTest, FixedStreamArray) {
+  std::vector<uint32_t> Ints = {90823, 12908, 109823, 209823};
+  ArrayRef<uint8_t> IntBytes(reinterpret_cast<uint8_t *>(Ints.data()),
+                             Ints.size() * sizeof(uint32_t));
+
+  initializeInput(IntBytes);
+
+  for (auto &Stream : Streams) {
+    MutableArrayRef<uint8_t> Buffer;
+    ASSERT_EQ(InputData.size(), Stream.Input->getLength());
+
+    FixedStreamArray<uint32_t> Array(*Stream.Input);
+    auto Iter = Array.begin();
+    ASSERT_EQ(Ints[0], *Iter++);
+    ASSERT_EQ(Ints[1], *Iter++);
+    ASSERT_EQ(Ints[2], *Iter++);
+    ASSERT_EQ(Ints[3], *Iter++);
+    ASSERT_EQ(Array.end(), Iter);
+  }
+}
+
+// Test that VarStreamArray works correctly.
+TEST_F(BinaryStreamTest, VarStreamArray) {
+  StringLiteral Strings("1. Test2. Longer Test3. Really Long Test4. Super "
+                        "Extra Longest Test Of All");
+  ArrayRef<uint8_t> StringBytes(
+      reinterpret_cast<const uint8_t *>(Strings.data()), Strings.size());
+  initializeInput(StringBytes);
+
+  struct StringExtractor {
+  public:
+    Error operator()(BinaryStreamRef Stream, uint32_t &Len, StringRef &Item) {
+      if (Index == 0)
+        Len = strlen("1. Test");
+      else if (Index == 1)
+        Len = strlen("2. Longer Test");
+      else if (Index == 2)
+        Len = strlen("3. Really Long Test");
+      else
+        Len = strlen("4. Super Extra Longest Test Of All");
+      ArrayRef<uint8_t> Bytes;
+      if (auto EC = Stream.readBytes(0, Len, Bytes))
+        return EC;
+      Item =
+          StringRef(reinterpret_cast<const char *>(Bytes.data()), Bytes.size());
+      ++Index;
+      return Error::success();
+    }
+
+  private:
+    uint32_t Index = 0;
+  };
+
+  for (auto &Stream : Streams) {
+    VarStreamArray<StringRef, StringExtractor> Array(*Stream.Input);
+    auto Iter = Array.begin();
+    ASSERT_EQ("1. Test", *Iter++);
+    ASSERT_EQ("2. Longer Test", *Iter++);
+    ASSERT_EQ("3. Really Long Test", *Iter++);
+    ASSERT_EQ("4. Super Extra Longest Test Of All", *Iter++);
+    ASSERT_EQ(Array.end(), Iter);
+  }
+}
+
+TEST_F(BinaryStreamTest, StreamReaderBounds) {
+  std::vector<uint8_t> Bytes;
+
+  initializeInput(Bytes);
+  for (auto &Stream : Streams) {
+    StringRef S;
+    BinaryStreamReader Reader(*Stream.Input);
+    EXPECT_EQ(0U, Reader.bytesRemaining());
+    EXPECT_ERROR(Reader.readFixedString(S, 1));
+  }
+
+  Bytes.resize(5);
+  initializeInput(Bytes);
+  for (auto &Stream : Streams) {
+    StringRef S;
+    BinaryStreamReader Reader(*Stream.Input);
+    EXPECT_EQ(Bytes.size(), Reader.bytesRemaining());
+    EXPECT_NO_ERROR(Reader.readFixedString(S, 5));
+    EXPECT_ERROR(Reader.readFixedString(S, 6));
+  }
+}
+
+TEST_F(BinaryStreamTest, StreamReaderIntegers) {
+  support::ulittle64_t Little{908234};
+  support::ubig32_t Big{28907823};
+  short NS = 2897;
+  int NI = -89723;
+  unsigned long NUL = 902309023UL;
+  constexpr uint32_t Size =
+      sizeof(Little) + sizeof(Big) + sizeof(NS) + sizeof(NI) + sizeof(NUL);
+
+  initializeOutput(Size);
+  initializeInputFromOutput();
+
+  for (auto &Stream : Streams) {
+    BinaryStreamWriter Writer(*Stream.Output);
+    ASSERT_NO_ERROR(Writer.writeObject(Little));
+    ASSERT_NO_ERROR(Writer.writeObject(Big));
+    ASSERT_NO_ERROR(Writer.writeInteger(NS));
+    ASSERT_NO_ERROR(Writer.writeInteger(NI));
+    ASSERT_NO_ERROR(Writer.writeInteger(NUL));
+
+    const support::ulittle64_t *Little2;
+    const support::ubig32_t *Big2;
+    short NS2;
+    int NI2;
+    unsigned long NUL2;
+
+    // 1. Reading fields individually.
+    BinaryStreamReader Reader(*Stream.Input);
+    ASSERT_NO_ERROR(Reader.readObject(Little2));
+    ASSERT_NO_ERROR(Reader.readObject(Big2));
+    ASSERT_NO_ERROR(Reader.readInteger(NS2));
+    ASSERT_NO_ERROR(Reader.readInteger(NI2));
+    ASSERT_NO_ERROR(Reader.readInteger(NUL2));
+    ASSERT_EQ(0U, Reader.bytesRemaining());
+
+    EXPECT_EQ(Little, *Little2);
+    EXPECT_EQ(Big, *Big2);
+    EXPECT_EQ(NS, NS2);
+    EXPECT_EQ(NI, NI2);
+    EXPECT_EQ(NUL, NUL2);
+  }
+}
+
+TEST_F(BinaryStreamTest, StreamReaderIntegerArray) {
+  // 1. Arrays of integers
+  std::vector<int> Ints = {1, 2, 3, 4, 5};
+  ArrayRef<uint8_t> IntBytes(reinterpret_cast<uint8_t *>(&Ints[0]),
+                             Ints.size() * sizeof(int));
+
+  initializeInput(IntBytes);
+  for (auto &Stream : Streams) {
+    BinaryStreamReader Reader(*Stream.Input);
+    ArrayRef<int> IntsRef;
+    ASSERT_NO_ERROR(Reader.readArray(IntsRef, Ints.size()));
+    ASSERT_EQ(0U, Reader.bytesRemaining());
+    EXPECT_EQ(makeArrayRef(Ints), IntsRef);
+
+    Reader.setOffset(0);
+    FixedStreamArray<int> FixedIntsRef;
+    ASSERT_NO_ERROR(Reader.readArray(FixedIntsRef, Ints.size()));
+    ASSERT_EQ(0U, Reader.bytesRemaining());
+    ASSERT_EQ(Ints, std::vector<int>(FixedIntsRef.begin(), FixedIntsRef.end()));
+  }
+}
+
+TEST_F(BinaryStreamTest, StreamReaderEnum) {
+  enum class MyEnum : int64_t { Foo = -10, Bar = 0, Baz = 10 };
+
+  std::vector<MyEnum> Enums = {MyEnum::Bar, MyEnum::Baz, MyEnum::Foo};
+
+  initializeOutput(Enums.size() * sizeof(MyEnum));
+  initializeInputFromOutput();
+  for (auto &Stream : Streams) {
+    BinaryStreamWriter Writer(*Stream.Output);
+    for (auto Value : Enums)
+      ASSERT_NO_ERROR(Writer.writeEnum(Value));
+
+    BinaryStreamReader Reader(*Stream.Input);
+
+    ArrayRef<MyEnum> Array;
+    FixedStreamArray<MyEnum> FSA;
+
+    for (size_t I = 0; I < Enums.size(); ++I) {
+      MyEnum Value;
+      ASSERT_NO_ERROR(Reader.readEnum(Value));
+      EXPECT_EQ(Enums[I], Value);
+    }
+    ASSERT_EQ(0U, Reader.bytesRemaining());
+  }
+}
+
+TEST_F(BinaryStreamTest, StreamReaderObject) {
+  struct Foo {
+    int X;
+    double Y;
+    char Z;
+  };
+
+  std::vector<Foo> Foos;
+  Foos.push_back({-42, 42.42, 42});
+  Foos.push_back({100, 3.1415, static_cast<char>(-89)});
+
+  const uint8_t *Bytes = reinterpret_cast<const uint8_t *>(&Foos[0]);
+
+  initializeInput(makeArrayRef(Bytes, 2 * sizeof(Foo)));
+
+  for (auto &Stream : Streams) {
+    // 1. Reading object pointers.
+    BinaryStreamReader Reader(*Stream.Input);
+    const Foo *FPtrOut = nullptr;
+    const Foo *GPtrOut = nullptr;
+    ASSERT_NO_ERROR(Reader.readObject(FPtrOut));
+    ASSERT_NO_ERROR(Reader.readObject(GPtrOut));
+    EXPECT_EQ(0U, Reader.bytesRemaining());
+    EXPECT_EQ(0, ::memcmp(&Foos[0], FPtrOut, sizeof(Foo)));
+    EXPECT_EQ(0, ::memcmp(&Foos[1], GPtrOut, sizeof(Foo)));
+  }
+}
+
+TEST_F(BinaryStreamTest, StreamReaderStrings) {
+  std::vector<uint8_t> Bytes = {'O',  'n', 'e', '\0', 'T', 'w', 'o',
+                                '\0', 'T', 'h', 'r',  'e', 'e', '\0',
+                                'F',  'o', 'u', 'r',  '\0'};
+  initializeInput(Bytes);
+
+  for (auto &Stream : Streams) {
+    BinaryStreamReader Reader(*Stream.Input);
+
+    StringRef S1;
+    StringRef S2;
+    StringRef S3;
+    StringRef S4;
+    ASSERT_NO_ERROR(Reader.readCString(S1));
+    ASSERT_NO_ERROR(Reader.readCString(S2));
+    ASSERT_NO_ERROR(Reader.readCString(S3));
+    ASSERT_NO_ERROR(Reader.readCString(S4));
+    ASSERT_EQ(0U, Reader.bytesRemaining());
+
+    EXPECT_EQ("One", S1);
+    EXPECT_EQ("Two", S2);
+    EXPECT_EQ("Three", S3);
+    EXPECT_EQ("Four", S4);
+
+    S1 = S2 = S3 = S4 = "";
+    Reader.setOffset(0);
+    ASSERT_NO_ERROR(Reader.readFixedString(S1, 3));
+    ASSERT_NO_ERROR(Reader.skip(1));
+    ASSERT_NO_ERROR(Reader.readFixedString(S2, 3));
+    ASSERT_NO_ERROR(Reader.skip(1));
+    ASSERT_NO_ERROR(Reader.readFixedString(S3, 5));
+    ASSERT_NO_ERROR(Reader.skip(1));
+    ASSERT_NO_ERROR(Reader.readFixedString(S4, 4));
+    ASSERT_NO_ERROR(Reader.skip(1));
+    ASSERT_EQ(0U, Reader.bytesRemaining());
+
+    EXPECT_EQ("One", S1);
+    EXPECT_EQ("Two", S2);
+    EXPECT_EQ("Three", S3);
+    EXPECT_EQ("Four", S4);
+  }
+}
+
+TEST_F(BinaryStreamTest, StreamWriterBounds) {
+  initializeOutput(5);
+
+  for (auto &Stream : Streams) {
+    BinaryStreamWriter Writer(*Stream.Output);
+
+    // 1. Can write a string that exactly fills the buffer.
+    EXPECT_EQ(5U, Writer.bytesRemaining());
+    EXPECT_NO_ERROR(Writer.writeFixedString("abcde"));
+    EXPECT_EQ(0U, Writer.bytesRemaining());
+
+    // 2. Can write an empty string even when you're full
+    EXPECT_NO_ERROR(Writer.writeFixedString(""));
+    EXPECT_ERROR(Writer.writeFixedString("a"));
+
+    // 3. Can't write a string that is one character too long.
+    Writer.setOffset(0);
+    EXPECT_ERROR(Writer.writeFixedString("abcdef"));
+  }
+}
+
+TEST_F(BinaryStreamTest, StreamWriterIntegerArrays) {
+  // 3. Arrays of integers
+  std::vector<int> SourceInts = {1, 2, 3, 4, 5};
+  ArrayRef<uint8_t> SourceBytes(reinterpret_cast<uint8_t *>(&SourceInts[0]),
+                                SourceInts.size() * sizeof(int));
+
+  initializeInput(SourceBytes);
+  initializeOutputFromInput();
+
+  for (auto &Stream : Streams) {
+    BinaryStreamReader Reader(*Stream.Input);
+    BinaryStreamWriter Writer(*Stream.Output);
+    ArrayRef<int> Ints;
+    ArrayRef<int> Ints2;
+    // First read them, then write them, then read them back.
+    ASSERT_NO_ERROR(Reader.readArray(Ints, SourceInts.size()));
+    ASSERT_NO_ERROR(Writer.writeArray(Ints));
+
+    BinaryStreamReader ReaderBacker(*Stream.Output);
+    ASSERT_NO_ERROR(ReaderBacker.readArray(Ints2, SourceInts.size()));
+
+    EXPECT_EQ(makeArrayRef(SourceInts), Ints2);
+  }
+}
+
+TEST_F(BinaryStreamTest, StringWriterStrings) {
+  StringRef Strings[] = {"First", "Second", "Third", "Fourth"};
+
+  size_t Length = 0;
+  for (auto S : Strings)
+    Length += S.size() + 1;
+  initializeOutput(Length);
+  initializeInputFromOutput();
+
+  for (auto &Stream : Streams) {
+    BinaryStreamWriter Writer(*Stream.Output);
+    for (auto S : Strings)
+      ASSERT_NO_ERROR(Writer.writeCString(S));
+    std::vector<StringRef> InStrings;
+    BinaryStreamReader Reader(*Stream.Input);
+    while (!Reader.empty()) {
+      StringRef S;
+      ASSERT_NO_ERROR(Reader.readCString(S));
+      InStrings.push_back(S);
+    }
+    EXPECT_EQ(makeArrayRef(Strings), makeArrayRef(InStrings));
+  }
+}
+}
+
+namespace {
+struct BinaryItemStreamObject {
+  explicit BinaryItemStreamObject(ArrayRef<uint8_t> Bytes) : Bytes(Bytes) {}
+
+  ArrayRef<uint8_t> Bytes;
+};
+}
+
+namespace llvm {
+template <> struct BinaryItemTraits<BinaryItemStreamObject> {
+  static size_t length(const BinaryItemStreamObject &Item) {
+    return Item.Bytes.size();
+  }
+
+  static ArrayRef<uint8_t> bytes(const BinaryItemStreamObject &Item) {
+    return Item.Bytes;
+  }
+};
+}
+
+namespace {
+
+TEST_F(BinaryStreamTest, BinaryItemStream) {
+  std::vector<BinaryItemStreamObject> Objects;
+
+  struct Foo {
+    int X;
+    double Y;
+  };
+  std::vector<Foo> Foos = {{1, 1.0}, {2, 2.0}, {3, 3.0}};
+  BumpPtrAllocator Allocator;
+  for (const auto &F : Foos) {
+    uint8_t *Ptr = Allocator.Allocate<uint8_t>(sizeof(Foo));
+    MutableArrayRef<uint8_t> Buffer(Ptr, sizeof(Foo));
+    MutableBinaryByteStream Stream(Buffer, llvm::support::big);
+    BinaryStreamWriter Writer(Stream);
+    ASSERT_NO_ERROR(Writer.writeObject(F));
+    Objects.push_back(BinaryItemStreamObject(Buffer));
+  }
+
+  BinaryItemStream<BinaryItemStreamObject> ItemStream(big);
+  ItemStream.setItems(Objects);
+  BinaryStreamReader Reader(ItemStream);
+
+  for (const auto &F : Foos) {
+    const Foo *F2;
+    ASSERT_NO_ERROR(Reader.readObject(F2));
+
+    EXPECT_EQ(F.X, F2->X);
+    EXPECT_DOUBLE_EQ(F.Y, F2->Y);
+  }
+}
+
+} // end anonymous namespace
diff --git a/unittests/DebugInfo/PDB/CMakeLists.txt b/unittests/DebugInfo/PDB/CMakeLists.txt
index cbbbd817748..cb57ada5ee4 100644
--- a/unittests/DebugInfo/PDB/CMakeLists.txt
+++ b/unittests/DebugInfo/PDB/CMakeLists.txt
@@ -5,6 +5,7 @@ set(LLVM_LINK_COMPONENTS
   )
 
 set(DebugInfoPDBSources
+  BinaryStreamTest.cpp
   HashTableTest.cpp
   MappedBlockStreamTest.cpp
   StringTableBuilderTest.cpp