Index: lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/string/Makefile
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/string/Makefile
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/string/Makefile
@@ -4,4 +4,4 @@
 
 USE_LIBCPP := 1
 include $(LEVEL)/Makefile.rules
-CXXFLAGS += -O0
+CXXFLAGS += -std=c++11 -O0
Index: lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/string/TestDataFormatterLibcxxString.py
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/string/TestDataFormatterLibcxxString.py
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/string/TestDataFormatterLibcxxString.py
@@ -68,7 +68,9 @@
                 '(%s::string) q = "hello world"'%ns,
                 '(%s::string) Q = "quite a long std::strin with lots of info inside it"'%ns,
                 '(%s::string) IHaveEmbeddedZeros = "a\\0b\\0c\\0d"'%ns,
-                '(%s::wstring) IHaveEmbeddedZerosToo = L"hello world!\\0てざ ル゜䋨ミ㠧槊 きゅへ狦穤襩 じゃ馩リョ 䤦監"'%ns])
+                '(%s::wstring) IHaveEmbeddedZerosToo = L"hello world!\\0てざ ル゜䋨ミ㠧槊 きゅへ狦穤襩 じゃ馩リョ 䤦監"'%ns,
+                '(%s::u16string) u16_string = u"ß水氶"'%ns,
+                '(%s::u32string) u32_string = U"🍄🍅🍆🍌"'%ns])
 
         self.runCmd("n")
 
@@ -98,4 +100,6 @@
                 '(%s::string) q = "hello world"'%ns,
                 '(%s::string) Q = "quite a long std::strin with lots of info inside it"'%ns,
                 '(%s::string) IHaveEmbeddedZeros = "a\\0b\\0c\\0d"'%ns,
-                '(%s::wstring) IHaveEmbeddedZerosToo = L"hello world!\\0てざ ル゜䋨ミ㠧槊 きゅへ狦穤襩 じゃ馩リョ 䤦監"'%ns])
+                '(%s::wstring) IHaveEmbeddedZerosToo = L"hello world!\\0てざ ル゜䋨ミ㠧槊 きゅへ狦穤襩 じゃ馩リョ 䤦監"'%ns,
+                '(%s::u16string) u16_string = u"ß水氶"'%ns,
+                '(%s::u32string) u32_string = U"🍄🍅🍆🍌"'%ns])
Index: lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/string/main.cpp
===================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/string/main.cpp
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/data-formatter/data-formatter-stl/libcxx/string/main.cpp
@@ -10,6 +10,8 @@
     std::string TheVeryLongOne("1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890someText1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890");
     std::string IHaveEmbeddedZeros("a\0b\0c\0d",7);
     std::wstring IHaveEmbeddedZerosToo(L"hello world!\0てざ ル゜䋨ミ㠧槊 きゅへ狦穤襩 じゃ馩リョ 䤦監", 38);
+    std::u16string u16_string(u"ß水氶");
+    std::u32string u32_string(U"🍄🍅🍆🍌");
     S.assign(L"!!!!!"); // Set break point at this line.
     return 0;
 }
Index: lldb/trunk/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
===================================================================
--- lldb/trunk/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ lldb/trunk/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
@@ -405,8 +405,17 @@
 
 #ifndef LLDB_DISABLE_PYTHON
   lldb::TypeSummaryImplSP std_string_summary_sp(new CXXFunctionSummaryFormat(
-      stl_summary_flags, lldb_private::formatters::LibcxxStringSummaryProvider,
+      stl_summary_flags,
+      lldb_private::formatters::LibcxxStringSummaryProviderASCII,
       "std::string summary provider"));
+  lldb::TypeSummaryImplSP std_stringu16_summary_sp(new CXXFunctionSummaryFormat(
+      stl_summary_flags,
+      lldb_private::formatters::LibcxxStringSummaryProviderUTF16,
+      "std::u16string summary provider"));
+  lldb::TypeSummaryImplSP std_stringu32_summary_sp(new CXXFunctionSummaryFormat(
+      stl_summary_flags,
+      lldb_private::formatters::LibcxxStringSummaryProviderUTF32,
+      "std::u32string summary provider"));
   lldb::TypeSummaryImplSP std_wstring_summary_sp(new CXXFunctionSummaryFormat(
       stl_summary_flags, lldb_private::formatters::LibcxxWStringSummaryProvider,
       "std::wstring summary provider"));
@@ -420,6 +429,16 @@
                   "std::__1::allocator<char> >"),
       std_string_summary_sp);
   cpp_category_sp->GetTypeSummariesContainer()->Add(
+      ConstString(
+          "std::__1::basic_string<char16_t, std::__1::char_traits<char16_t>, "
+          "std::__1::allocator<char16_t> >"),
+      std_stringu16_summary_sp);
+  cpp_category_sp->GetTypeSummariesContainer()->Add(
+      ConstString(
+          "std::__1::basic_string<char32_t, std::__1::char_traits<char32_t>, "
+          "std::__1::allocator<char32_t> >"),
+      std_stringu32_summary_sp);
+  cpp_category_sp->GetTypeSummariesContainer()->Add(
       ConstString("std::__ndk1::basic_string<char, "
                   "std::__ndk1::char_traits<char>, "
                   "std::__ndk1::allocator<char> >"),
Index: lldb/trunk/source/Plugins/Language/CPlusPlus/LibCxx.h
===================================================================
--- lldb/trunk/source/Plugins/Language/CPlusPlus/LibCxx.h
+++ lldb/trunk/source/Plugins/Language/CPlusPlus/LibCxx.h
@@ -19,9 +19,17 @@
 namespace lldb_private {
 namespace formatters {
 
-bool LibcxxStringSummaryProvider(
+bool LibcxxStringSummaryProviderASCII(
     ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &options); // libc++ std::string
+    const TypeSummaryOptions &summary_options); // libc++ std::string
+
+bool LibcxxStringSummaryProviderUTF16(
+    ValueObject &valobj, Stream &stream,
+    const TypeSummaryOptions &summary_options); // libc++ std::u16string
+
+bool LibcxxStringSummaryProviderUTF32(
+    ValueObject &valobj, Stream &stream,
+    const TypeSummaryOptions &summary_options); // libc++ std::u32string
 
 bool LibcxxWStringSummaryProvider(
     ValueObject &valobj, Stream &stream,
Index: lldb/trunk/source/Plugins/Language/CPlusPlus/LibCxx.cpp
===================================================================
--- lldb/trunk/source/Plugins/Language/CPlusPlus/LibCxx.cpp
+++ lldb/trunk/source/Plugins/Language/CPlusPlus/LibCxx.cpp
@@ -599,9 +599,10 @@
   return true;
 }
 
-bool lldb_private::formatters::LibcxxStringSummaryProvider(
-    ValueObject &valobj, Stream &stream,
-    const TypeSummaryOptions &summary_options) {
+template <StringPrinter::StringElementType element_type>
+bool LibcxxStringSummaryProvider(ValueObject &valobj, Stream &stream,
+                                 const TypeSummaryOptions &summary_options,
+                                 std::string prefix_token = "") {
   uint64_t size = 0;
   ValueObjectSP location_sp;
 
@@ -630,12 +631,37 @@
 
   options.SetData(extractor);
   options.SetStream(&stream);
-  options.SetPrefixToken(nullptr);
+
+  if (prefix_token.empty())
+    options.SetPrefixToken(nullptr);
+  else
+    options.SetPrefixToken(prefix_token);
+
   options.SetQuote('"');
   options.SetSourceSize(size);
   options.SetBinaryZeroIsTerminator(false);
-  StringPrinter::ReadBufferAndDumpToStream<
-      StringPrinter::StringElementType::ASCII>(options);
+  StringPrinter::ReadBufferAndDumpToStream<element_type>(options);
 
   return true;
 }
+
+bool lldb_private::formatters::LibcxxStringSummaryProviderASCII(
+    ValueObject &valobj, Stream &stream,
+    const TypeSummaryOptions &summary_options) {
+  return LibcxxStringSummaryProvider<StringPrinter::StringElementType::ASCII>(
+      valobj, stream, summary_options);
+}
+
+bool lldb_private::formatters::LibcxxStringSummaryProviderUTF16(
+    ValueObject &valobj, Stream &stream,
+    const TypeSummaryOptions &summary_options) {
+  return LibcxxStringSummaryProvider<StringPrinter::StringElementType::UTF16>(
+      valobj, stream, summary_options, "u");
+}
+
+bool lldb_private::formatters::LibcxxStringSummaryProviderUTF32(
+    ValueObject &valobj, Stream &stream,
+    const TypeSummaryOptions &summary_options) {
+  return LibcxxStringSummaryProvider<StringPrinter::StringElementType::UTF32>(
+      valobj, stream, summary_options, "U");
+}