Index: unittests/Utility/CMakeLists.txt
===================================================================
--- unittests/Utility/CMakeLists.txt
+++ unittests/Utility/CMakeLists.txt
@@ -14,6 +14,7 @@
   NameMatchesTest.cpp
   StatusTest.cpp
   StreamTeeTest.cpp
+  StreamTest.cpp
   StringExtractorTest.cpp
   StructuredDataTest.cpp
   TildeExpressionResolverTest.cpp
Index: unittests/Utility/StreamTest.cpp
===================================================================
--- /dev/null
+++ unittests/Utility/StreamTest.cpp
@@ -0,0 +1,480 @@
+//===-- StreamTest.cpp ------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Utility/StreamString.h"
+#include "gtest/gtest.h"
+
+using namespace lldb_private;
+
+namespace {
+struct StreamTest : ::testing::Test {
+  // Note: Stream is an abstract class, so we use StreamString to test it. To
+  // make it easier to change this later, only methods in this class explicitly
+  // refer to the StringStream class.
+  StreamString s;
+  // We return here a std::string because that way gtest can print better
+  // assertion messages.
+  std::string TakeValue() {
+    std::string result = s.GetString().str();
+    s.Clear();
+    return result;
+  }
+};
+}
+
+namespace {
+// A StreamTest where we expect the Stream output to be binary.
+struct BinaryStreamTest : StreamTest {
+  void SetUp() override {
+    s.GetFlags().Set(Stream::eBinary);
+  }
+};
+}
+
+TEST_F(StreamTest, ChangingByteOrder) {
+  s.SetByteOrder(lldb::eByteOrderPDP);
+  EXPECT_EQ(lldb::eByteOrderPDP, s.GetByteOrder());
+}
+
+TEST_F(StreamTest, PutChar) {
+  s.PutChar('a');
+  EXPECT_EQ("a", TakeValue());
+
+  s.PutChar('1');
+  EXPECT_EQ("1", TakeValue());
+}
+
+TEST_F(StreamTest, PutCharWhitespace) {
+  s.PutChar(' ');
+  EXPECT_EQ(" ", TakeValue());
+
+  s.PutChar('\n');
+  EXPECT_EQ("\n", TakeValue());
+
+  s.PutChar('\r');
+  EXPECT_EQ("\r", TakeValue());
+
+  s.PutChar('\t');
+  EXPECT_EQ("\t", TakeValue());
+}
+
+TEST_F(StreamTest, PutCString) {
+  s.PutCString("");
+  EXPECT_EQ("", TakeValue());
+
+  s.PutCString("foobar");
+  EXPECT_EQ("foobar", TakeValue());
+
+  s.PutCString(" ");
+  EXPECT_EQ(" ", TakeValue());
+}
+
+TEST_F(StreamTest, PutCStringWithStringRef) {
+  s.PutCString(llvm::StringRef(""));
+  EXPECT_EQ("", TakeValue());
+
+  s.PutCString(llvm::StringRef("foobar"));
+  EXPECT_EQ("foobar", TakeValue());
+
+  s.PutCString(llvm::StringRef(" "));
+  EXPECT_EQ(" ", TakeValue());
+}
+
+TEST_F(StreamTest, QuotedCString) {
+  s.QuotedCString("foo");
+  EXPECT_EQ(R"("foo")", TakeValue());
+
+  s.QuotedCString("ba r");
+  EXPECT_EQ(R"("ba r")", TakeValue());
+
+  s.QuotedCString(" ");
+  EXPECT_EQ(R"(" ")", TakeValue());
+}
+
+TEST_F(StreamTest, PutCharNull) {
+  s.PutChar('\0');
+  EXPECT_EQ(std::string("\0", 1), TakeValue());
+
+  s.PutChar('a');
+  EXPECT_EQ(std::string("a", 1), TakeValue());
+}
+
+TEST_F(StreamTest, PutCStringAsRawHex8) {
+  s.PutCStringAsRawHex8("");
+  // FIXME: Check that printing 00 on an empty string is the intended behavior.
+  // It seems kind of unexpected  that we print the trailing 0 byte for empty
+  // strings, but not for non-empty strings.
+  EXPECT_EQ("00", TakeValue());
+
+  s.PutCStringAsRawHex8("foobar");
+  EXPECT_EQ("666f6f626172", TakeValue());
+
+  s.PutCStringAsRawHex8(" ");
+  EXPECT_EQ("20", TakeValue());
+}
+
+TEST_F(StreamTest, PutHex8) {
+  s.PutHex8((uint8_t)55);
+  EXPECT_EQ("37", TakeValue());
+  s.PutHex8(std::numeric_limits<uint8_t>::max());
+  EXPECT_EQ("ff", TakeValue());
+  s.PutHex8((uint8_t)0);
+  EXPECT_EQ("00", TakeValue());
+}
+
+TEST_F(StreamTest, PutNHex8) {
+  s.PutNHex8(0, (uint8_t)55);
+  EXPECT_EQ("", TakeValue());
+  s.PutNHex8(1, (uint8_t)55);
+  EXPECT_EQ("37", TakeValue());
+  s.PutNHex8(2, (uint8_t)55);
+  EXPECT_EQ("3737", TakeValue());
+  s.PutNHex8(1, (uint8_t)56);
+  EXPECT_EQ("38", TakeValue());
+}
+
+TEST_F(StreamTest, PutHex16ByteOrderLittle) {
+  s.PutHex16(0x1234U, lldb::eByteOrderLittle);
+  EXPECT_EQ("3412", TakeValue());
+  s.PutHex16(std::numeric_limits<uint16_t>::max(), lldb::eByteOrderLittle);
+  EXPECT_EQ("ffff", TakeValue());
+  s.PutHex16(0U, lldb::eByteOrderLittle);
+  EXPECT_EQ("0000", TakeValue());
+}
+
+TEST_F(StreamTest, PutHex16ByteOrderBig) {
+  s.PutHex16(0x1234U, lldb::eByteOrderBig);
+  EXPECT_EQ("1234", TakeValue());
+  s.PutHex16(std::numeric_limits<uint16_t>::max(), lldb::eByteOrderBig);
+  EXPECT_EQ("ffff", TakeValue());
+  s.PutHex16(0U, lldb::eByteOrderBig);
+  EXPECT_EQ("0000", TakeValue());
+}
+
+TEST_F(StreamTest, PutHex32ByteOrderLittle) {
+  s.PutHex32(0x12345678U, lldb::eByteOrderLittle);
+  EXPECT_EQ("78563412", TakeValue());
+  s.PutHex32(std::numeric_limits<uint32_t>::max(), lldb::eByteOrderLittle);
+  EXPECT_EQ("ffffffff", TakeValue());
+  s.PutHex32(0U, lldb::eByteOrderLittle);
+  EXPECT_EQ("00000000", TakeValue());
+}
+
+TEST_F(StreamTest, PutHex32ByteOrderBig) {
+  s.PutHex32(0x12345678U, lldb::eByteOrderBig);
+  EXPECT_EQ("12345678", TakeValue());
+  s.PutHex32(std::numeric_limits<uint32_t>::max(), lldb::eByteOrderBig);
+  EXPECT_EQ("ffffffff", TakeValue());
+  s.PutHex32(0U, lldb::eByteOrderBig);
+  EXPECT_EQ("00000000", TakeValue());
+}
+
+TEST_F(StreamTest, PutHex64ByteOrderLittle) {
+  s.PutHex64(0x1234567890ABCDEFU, lldb::eByteOrderLittle);
+  EXPECT_EQ("efcdab9078563412", TakeValue());
+  s.PutHex64(std::numeric_limits<uint64_t>::max(), lldb::eByteOrderLittle);
+  EXPECT_EQ("ffffffffffffffff", TakeValue());
+  s.PutHex64(0U, lldb::eByteOrderLittle);
+  EXPECT_EQ("0000000000000000", TakeValue());
+}
+
+TEST_F(StreamTest, PutHex64ByteOrderBig) {
+  s.PutHex64(0x1234567890ABCDEFU, lldb::eByteOrderBig);
+  EXPECT_EQ("1234567890abcdef", TakeValue());
+  s.PutHex64(std::numeric_limits<uint64_t>::max(), lldb::eByteOrderBig);
+  EXPECT_EQ("ffffffffffffffff", TakeValue());
+  s.PutHex64(0U, lldb::eByteOrderBig);
+  EXPECT_EQ("0000000000000000", TakeValue());
+}
+
+//------------------------------------------------------------------------------
+// Shift operator tests.
+//------------------------------------------------------------------------------
+
+TEST_F(StreamTest, ShiftOperatorChars) {
+  s << 'a' << 'b';
+  EXPECT_EQ("ab", TakeValue());
+}
+
+TEST_F(StreamTest, ShiftOperatorStrings) {
+  s << "cstring\n";
+  s << llvm::StringRef("llvm::StringRef\n");
+  EXPECT_EQ("cstring\nllvm::StringRef\n", TakeValue());
+}
+
+TEST_F(StreamTest, ShiftOperatorInts) {
+  s << std::numeric_limits<int8_t>::max() << " ";
+  s << std::numeric_limits<int16_t>::max() << " ";
+  s << std::numeric_limits<int32_t>::max() << " ";
+  s << std::numeric_limits<int64_t>::max();
+  EXPECT_EQ("127 32767 2147483647 9223372036854775807", TakeValue());
+}
+
+TEST_F(StreamTest, ShiftOperatorUInts) {
+  s << std::numeric_limits<uint8_t>::max() << " ";
+  s << std::numeric_limits<uint16_t>::max() << " ";
+  s << std::numeric_limits<uint32_t>::max() << " ";
+  s << std::numeric_limits<uint64_t>::max();
+  EXPECT_EQ("ff ffff ffffffff ffffffffffffffff", TakeValue());
+}
+
+TEST_F(StreamTest, ShiftOperatorPtr) {
+  // This test is a bit tricky because pretty much everything related to
+  // pointer printing seems to lead to UB or IB. So let's make the most basic
+  // test that just checks that we print *something*. This way we at least know
+  // that pointer printing doesn't do really bad things (e.g. crashing, reading
+  // OOB/uninitialized memory which the sanitizers would spot).
+
+  // Shift our own pointer to the output.
+  int i = 3;
+  int *ptr = &i;
+  s << ptr;
+
+  EXPECT_TRUE(!TakeValue().empty());
+}
+
+TEST_F(StreamTest, PutPtr) {
+  // See the ShiftOperatorPtr test for the rationale.
+  int i = 3;
+  int *ptr = &i;
+  s.PutPointer(ptr);
+
+  EXPECT_TRUE(!TakeValue().empty());
+}
+
+// Alias to make it more clear that 'invalid' means for the Stream interface
+// that it should use the host byte order.
+const static auto hostByteOrder = lldb::eByteOrderInvalid;
+
+//------------------------------------------------------------------------------
+// PutRawBytes/PutBytesAsRawHex tests.
+//------------------------------------------------------------------------------
+
+TEST_F(StreamTest, PutBytesAsRawHex8ToBigEndian) {
+  uint32_t value = 0x12345678;
+  s.PutBytesAsRawHex8(static_cast<void*>(&value), sizeof(value),
+                      hostByteOrder, lldb::eByteOrderBig);
+  EXPECT_EQ("78563412", TakeValue());
+}
+
+TEST_F(StreamTest, PutRawBytesToBigEndian) {
+  uint32_t value = 0x12345678;
+  s.PutRawBytes(static_cast<void*>(&value), sizeof(value),
+                      hostByteOrder, lldb::eByteOrderBig);
+  EXPECT_EQ("\x78\x56\x34\x12", TakeValue());
+}
+
+TEST_F(StreamTest, PutBytesAsRawHex8ToLittleEndian) {
+  uint32_t value = 0x12345678;
+  s.PutBytesAsRawHex8(static_cast<void*>(&value), sizeof(value),
+                      hostByteOrder, lldb::eByteOrderLittle);
+  EXPECT_EQ("12345678", TakeValue());
+}
+
+TEST_F(StreamTest, PutRawBytesToLittleEndian) {
+  uint32_t value = 0x12345678;
+  s.PutRawBytes(static_cast<void*>(&value), sizeof(value),
+                      hostByteOrder, lldb::eByteOrderLittle);
+  EXPECT_EQ("\x12\x34\x56\x78", TakeValue());
+}
+
+TEST_F(StreamTest, PutBytesAsRawHex8ToMixedEndian) {
+  uint32_t value = 0x12345678;
+  s.PutBytesAsRawHex8(static_cast<void*>(&value), sizeof(value),
+                      hostByteOrder, lldb::eByteOrderPDP);
+
+  // FIXME: PDP byte order is not actually implemented but Stream just silently
+  // prints the value in some random byte order...
+#if 0
+  EXPECT_EQ("34127856", TakeValue());
+#endif
+}
+
+TEST_F(StreamTest, PutRawBytesToMixedEndian) {
+  uint32_t value = 0x12345678;
+  s.PutRawBytes(static_cast<void*>(&value), sizeof(value),
+                      lldb::eByteOrderInvalid, lldb::eByteOrderPDP);
+
+  // FIXME: PDP byte order is not actually implemented but Stream just silently
+  // prints the value in some random byte order...
+#if 0
+  EXPECT_EQ("\x34\x12\x78\x56", TakeValue());
+#endif
+}
+
+//------------------------------------------------------------------------------
+// ULEB128 support for binary streams.
+//------------------------------------------------------------------------------
+
+TEST_F(BinaryStreamTest, PutULEB128OneByte) {
+  auto bytes = s.PutULEB128(0x74ULL);
+  EXPECT_EQ("\x74", TakeValue());
+  EXPECT_EQ(1U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutULEB128TwoBytes) {
+  auto bytes = s.PutULEB128(0x1985ULL);
+  EXPECT_EQ("\x85\x33", TakeValue());
+  EXPECT_EQ(2U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutULEB128ThreeBytes) {
+  auto bytes = s.PutULEB128(0x5023ULL);
+  EXPECT_EQ("\xA3\xA0\x1", TakeValue());
+  EXPECT_EQ(3U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutULEB128FourBytes) {
+  auto bytes = s.PutULEB128(0xA48032ULL);
+  EXPECT_EQ("\xB2\x80\x92\x5", TakeValue());
+  EXPECT_EQ(4U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutULEB128FiveBytes) {
+  auto bytes = s.PutULEB128(0x12345678ULL);
+  EXPECT_EQ("\xF8\xAC\xD1\x91\x1", TakeValue());
+  EXPECT_EQ(5U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutULEB128SixBytes) {
+  auto bytes = s.PutULEB128(0xABFE3FAFDFULL);
+  EXPECT_EQ("\xDF\xDF\xFE\xF1\xBF\x15", TakeValue());
+  EXPECT_EQ(6U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutULEB128SevenBytes) {
+  auto bytes = s.PutULEB128(0xDABFE3FAFDFULL);
+  EXPECT_EQ("\xDF\xDF\xFE\xF1\xBF\xB5\x3", TakeValue());
+  EXPECT_EQ(7U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutULEB128EightBytes) {
+  auto bytes = s.PutULEB128(0x7CDABFE3FAFDFULL);
+  EXPECT_EQ("\xDF\xDF\xFE\xF1\xBF\xB5\xF3\x3", TakeValue());
+  EXPECT_EQ(8U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutULEB128NineBytes) {
+  auto bytes = s.PutULEB128(0x327CDABFE3FAFDFULL);
+  EXPECT_EQ("\xDF\xDF\xFE\xF1\xBF\xB5\xF3\x93\x3", TakeValue());
+  EXPECT_EQ(9U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutULEB128MaxValue) {
+  auto bytes = s.PutULEB128(std::numeric_limits<uint64_t>::max());
+  EXPECT_EQ("\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\x1", TakeValue());
+  EXPECT_EQ(10U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutULEB128Zero) {
+  auto bytes = s.PutULEB128(0x0U);
+  EXPECT_EQ(std::string("\0", 1), TakeValue());
+  EXPECT_EQ(1U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutULEB128One) {
+  auto bytes = s.PutULEB128(0x1U);
+  EXPECT_EQ("\x1", TakeValue());
+  EXPECT_EQ(1U, bytes);
+}
+
+//------------------------------------------------------------------------------
+// SLEB128 support for binary streams.
+//------------------------------------------------------------------------------
+
+TEST_F(BinaryStreamTest, PutSLEB128OneByte) {
+  auto bytes = s.PutSLEB128(0x74LL);
+  EXPECT_EQ(std::string("\xF4\0", 2), TakeValue());
+  EXPECT_EQ(2U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutSLEB128TwoBytes) {
+  auto bytes = s.PutSLEB128(0x1985LL);
+  EXPECT_EQ("\x85\x33", TakeValue());
+  EXPECT_EQ(2U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutSLEB128ThreeBytes) {
+  auto bytes = s.PutSLEB128(0x5023LL);
+  EXPECT_EQ("\xA3\xA0\x1", TakeValue());
+  EXPECT_EQ(3U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutSLEB128FourBytes) {
+  auto bytes = s.PutSLEB128(0xA48032LL);
+  EXPECT_EQ("\xB2\x80\x92\x5", TakeValue());
+  EXPECT_EQ(4U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutSLEB128FiveBytes) {
+  auto bytes = s.PutSLEB128(0x12345678LL);
+  EXPECT_EQ("\xF8\xAC\xD1\x91\x1", TakeValue());
+  EXPECT_EQ(5U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutSLEB128SixBytes) {
+  auto bytes = s.PutSLEB128(0xABFE3FAFDFLL);
+  EXPECT_EQ("\xDF\xDF\xFE\xF1\xBF\x15", TakeValue());
+  EXPECT_EQ(6U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutSLEB128SevenBytes) {
+  auto bytes = s.PutSLEB128(0xDABFE3FAFDFLL);
+  EXPECT_EQ("\xDF\xDF\xFE\xF1\xBF\xB5\x3", TakeValue());
+  EXPECT_EQ(7U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutSLEB128EightBytes) {
+  auto bytes = s.PutSLEB128(0x7CDABFE3FAFDFLL);
+  EXPECT_EQ("\xDF\xDF\xFE\xF1\xBF\xB5\xF3\x3", TakeValue());
+  EXPECT_EQ(8U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutSLEB128NineBytes) {
+  auto bytes = s.PutSLEB128(0x327CDABFE3FAFDFLL);
+  EXPECT_EQ("\xDF\xDF\xFE\xF1\xBF\xB5\xF3\x93\x3", TakeValue());
+  EXPECT_EQ(9U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutSLEB128MaxValue) {
+  auto bytes = s.PutSLEB128(std::numeric_limits<int64_t>::max());
+  EXPECT_EQ(std::string("\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\0", 10), TakeValue());
+  EXPECT_EQ(10U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutSLEB128Zero) {
+  auto bytes = s.PutSLEB128(0x0);
+  EXPECT_EQ(std::string("\0", 1), TakeValue());
+  EXPECT_EQ(1U, bytes);
+}
+
+TEST_F(BinaryStreamTest, PutSLEB128One) {
+  auto bytes = s.PutSLEB128(0x1);
+  EXPECT_EQ(std::string("\x1", 1), TakeValue());
+  EXPECT_EQ(1U, bytes);
+}
+
+//------------------------------------------------------------------------------
+// SLEB128/ULEB128 support for non-binary streams.
+//------------------------------------------------------------------------------
+
+// The logic for this is very simple, so it should be enough to test some basic
+// use cases.
+
+TEST_F(StreamTest, PutULEB128) {
+  auto bytes = s.PutULEB128(0x74ULL);
+  EXPECT_EQ("0x74", TakeValue());
+  EXPECT_EQ(4U, bytes);
+}
+
+TEST_F(StreamTest, PutSLEB128) {
+  auto bytes = s.PutSLEB128(0x1985LL);
+  EXPECT_EQ("0x6533", TakeValue());
+  EXPECT_EQ(6U, bytes);
+}