Index: lldb/include/lldb/Interpreter/CommandReturnObject.h
===================================================================
--- lldb/include/lldb/Interpreter/CommandReturnObject.h
+++ lldb/include/lldb/Interpreter/CommandReturnObject.h
@@ -158,8 +158,8 @@
 private:
   enum { eStreamStringIndex = 0, eImmediateStreamIndex = 1 };
 
-  StreamTee m_out_stream;
-  StreamTee m_err_stream;
+  NullEscaped<StreamTee> m_out_stream;
+  NullEscaped<StreamTee> m_err_stream;
 
   lldb::ReturnStatus m_status = lldb::eReturnStatusStarted;
 
Index: lldb/include/lldb/Utility/Stream.h
===================================================================
--- lldb/include/lldb/Utility/Stream.h
+++ lldb/include/lldb/Utility/Stream.h
@@ -412,6 +412,27 @@
   RawOstreamForward m_forwarder;
 };
 
+template <typename T> class NullEscaped : public T {
+public:
+  using T::T;
+  ~NullEscaped() = default;
+
+  static_assert(std::is_base_of<Stream, T>::value, "T must be a Stream");
+
+protected:
+  size_t WriteImpl(const void *s, size_t length) override {
+    llvm::StringRef input(static_cast<const char *>(s), length);
+    llvm::SmallVector<llvm::StringRef, 1> parts;
+    input.split(parts, '\0');
+    size_t written = T::WriteImpl(parts[0].data(), parts[0].size());
+    for (llvm::StringRef part : llvm::drop_begin(parts)) {
+      written += T::WriteImpl("\\0", 2);
+      written += T::WriteImpl(part.data(), part.size());
+    }
+    return written;
+  }
+};
+
 /// Output an address value to this stream.
 ///
 /// Put an address \a addr out to the stream with optional \a prefix and \a
Index: lldb/unittests/Utility/StreamTest.cpp
===================================================================
--- lldb/unittests/Utility/StreamTest.cpp
+++ lldb/unittests/Utility/StreamTest.cpp
@@ -25,16 +25,23 @@
     return result;
   }
 };
-}
+
+struct NullEscapedTest : ::testing::Test {
+  NullEscaped<StreamString> s;
+  std::string TakeValue() {
+    std::string result = s.GetString().str();
+    s.Clear();
+    return result;
+  }
+};
+} // namespace
 
 namespace {
 // A StreamTest where we expect the Stream output to be binary.
 struct BinaryStreamTest : StreamTest {
-  void SetUp() override {
-    s.GetFlags().Set(Stream::eBinary);
-  }
+  void SetUp() override { s.GetFlags().Set(Stream::eBinary); }
 };
-}
+} // namespace
 
 TEST_F(StreamTest, AddressPrefix) {
   DumpAddress(s.AsRawOstream(), 0x1, 1, "foo");
@@ -718,3 +725,21 @@
   EXPECT_EQ("0x6533", TakeValue());
   EXPECT_EQ(6U, bytes);
 }
+
+TEST_F(NullEscapedTest, NonNull) {
+  s.PutChar(' ');
+  EXPECT_EQ(1U, s.GetWrittenBytes());
+  EXPECT_EQ(" ", TakeValue());
+
+  s.PutCString(llvm::StringRef("\0", 1));
+  EXPECT_EQ(2U, s.GetWrittenBytes());
+  EXPECT_EQ("\\0", TakeValue());
+
+  s.PutCString(llvm::StringRef("foo\0bar\0baz", 11));
+  EXPECT_EQ(13U, s.GetWrittenBytes());
+  EXPECT_EQ("foo\\0bar\\0baz", TakeValue());
+
+  s.PutCString(llvm::StringRef("foo\0bar\0baz\0", 12));
+  EXPECT_EQ(15U, s.GetWrittenBytes());
+  EXPECT_EQ("foo\\0bar\\0baz\\0", TakeValue());
+}