Index: lldb/source/Plugins/Language/ClangCommon/ClangHighlighter.cpp
===================================================================
--- lldb/source/Plugins/Language/ClangCommon/ClangHighlighter.cpp
+++ lldb/source/Plugins/Language/ClangCommon/ClangHighlighter.cpp
@@ -139,6 +139,16 @@
   FileManager file_mgr(file_opts,
                        FileSystem::Instance().GetVirtualFileSystem());
 
+  // The line might end in a backslash which would cause Clang to drop the
+  // backslash and the terminating line feed. This makes sense when parsing C++,
+  // but when highlighting we care about preserving the backslash/newline. To
+  // not lose this information we remove the line feed here so that Clang knows
+  // this is just a single line we are highlighting. We add back the newline
+  // after tokenizing.
+  const bool line_had_cr_lf = line.endswith("\r\n");
+  const bool line_had_lf = line.endswith("\n") && !line_had_cr_lf;
+  line = line.trim("\r\n");
+
   unsigned line_number = previous_lines.count('\n') + 1U;
 
   // Let's build the actual source code Clang needs and setup some utility
@@ -227,6 +237,11 @@
     color.Apply(result, to_print);
   }
 
+  if (line_had_cr_lf)
+    result << "\r\n";
+  else if (line_had_lf)
+    result << "\n";
+
   // If we went over the whole file but couldn't find our own file, then
   // somehow our setup was wrong. When we're in release mode we just give the
   // user the normal line and pretend we don't know how to highlight it. In
Index: lldb/unittests/Language/Highlighting/HighlighterTest.cpp
===================================================================
--- lldb/unittests/Language/Highlighting/HighlighterTest.cpp
+++ lldb/unittests/Language/Highlighting/HighlighterTest.cpp
@@ -205,6 +205,43 @@
             highlightC("#include \"foo\" //c", s));
 }
 
+TEST_F(HighlighterTest, ClangPreserveNewLine) {
+  HighlightStyle s;
+  s.comment.Set("<cc>", "</cc>");
+
+  EXPECT_EQ("<cc>//</cc>\n", highlightC("//\n", s));
+}
+
+TEST_F(HighlighterTest, ClangTrailingBackslashBeforeNewline) {
+  HighlightStyle s;
+
+  EXPECT_EQ("\\\n", highlightC("\\\n", s));
+  EXPECT_EQ("\\\r\n", highlightC("\\\r\n", s));
+
+  EXPECT_EQ("#define a \\\n", highlightC("#define a \\\n", s));
+  EXPECT_EQ("#define a \\\r\n", highlightC("#define a \\\r\n", s));
+}
+
+TEST_F(HighlighterTest, ClangTrailingBackslashWithWhitespace) {
+  HighlightStyle s;
+
+  EXPECT_EQ("\\  \n", highlightC("\\  \n", s));
+  EXPECT_EQ("\\ \t\n", highlightC("\\ \t\n", s));
+  EXPECT_EQ("\\ \n", highlightC("\\ \n", s));
+  EXPECT_EQ("\\\t\n", highlightC("\\\t\n", s));
+
+  EXPECT_EQ("#define a \\  \n", highlightC("#define a \\  \n", s));
+  EXPECT_EQ("#define a \\ \t\n", highlightC("#define a \\ \t\n", s));
+  EXPECT_EQ("#define a \\ \n", highlightC("#define a \\ \n", s));
+  EXPECT_EQ("#define a \\\t\n", highlightC("#define a \\\t\n", s));
+}
+
+TEST_F(HighlighterTest, ClangTrailingBackslashMissingNewLine) {
+  HighlightStyle s;
+  EXPECT_EQ("\\", highlightC("\\", s));
+  EXPECT_EQ("#define a\\", highlightC("#define a\\", s));
+}
+
 TEST_F(HighlighterTest, ClangComments) {
   HighlightStyle s;
   s.comment.Set("<cc>", "</cc>");