1 files changed, 681 insertions, 0 deletions

diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
new file mode 100644
index 000000000000..abe89035c532
--- /dev/null
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
@@ -0,0 +1,681 @@
+//===-- LibCxx.cpp ----------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "LibCxx.h"
+
+#include "llvm/ADT/ScopeExit.h"
+#include "lldb/Core/Debugger.h"
+#include "lldb/Core/FormatEntity.h"
+#include "lldb/Core/ValueObject.h"
+#include "lldb/Core/ValueObjectConstResult.h"
+#include "lldb/DataFormatters/FormattersHelpers.h"
+#include "lldb/DataFormatters/StringPrinter.h"
+#include "lldb/DataFormatters/TypeSummary.h"
+#include "lldb/DataFormatters/VectorIterator.h"
+#include "lldb/Symbol/ClangASTContext.h"
+#include "lldb/Target/ProcessStructReader.h"
+#include "lldb/Target/SectionLoadList.h"
+#include "lldb/Target/Target.h"
+#include "lldb/Utility/DataBufferHeap.h"
+#include "lldb/Utility/Endian.h"
+#include "lldb/Utility/Status.h"
+#include "lldb/Utility/Stream.h"
+
+#include "Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.h"
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace lldb_private::formatters;
+
+bool lldb_private::formatters::LibcxxOptionalSummaryProvider(
+    ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
+  ValueObjectSP valobj_sp(valobj.GetNonSyntheticValue());
+  if (!valobj_sp)
+    return false;
+
+  // An optional either contains a value or not, the member __engaged_ is
+  // a bool flag, it is true if the optional has a value and false otherwise.
+  ValueObjectSP engaged_sp(
+      valobj_sp->GetChildMemberWithName(ConstString("__engaged_"), true));
+
+  if (!engaged_sp)
+    return false;
+
+  llvm::StringRef engaged_as_cstring(
+      engaged_sp->GetValueAsUnsigned(0) == 1 ? "true" : "false");
+
+  stream.Printf(" Has Value=%s ", engaged_as_cstring.data());
+
+  return true;
+}
+
+bool lldb_private::formatters::LibcxxFunctionSummaryProvider(
+    ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
+
+  ValueObjectSP valobj_sp(valobj.GetNonSyntheticValue());
+
+  if (!valobj_sp)
+    return false;
+
+  ExecutionContext exe_ctx(valobj_sp->GetExecutionContextRef());
+  Process *process = exe_ctx.GetProcessPtr();
+
+  if (process == nullptr)
+    return false;
+
+  CPPLanguageRuntime *cpp_runtime = CPPLanguageRuntime::Get(*process);
+
+  if (!cpp_runtime)
+    return false;
+
+  CPPLanguageRuntime::LibCppStdFunctionCallableInfo callable_info =
+      cpp_runtime->FindLibCppStdFunctionCallableInfo(valobj_sp);
+
+  switch (callable_info.callable_case) {
+  case CPPLanguageRuntime::LibCppStdFunctionCallableCase::Invalid:
+    stream.Printf(" __f_ = %" PRIu64, callable_info.member__f_pointer_value);
+    return false;
+    break;
+  case CPPLanguageRuntime::LibCppStdFunctionCallableCase::Lambda:
+    stream.Printf(
+        " Lambda in File %s at Line %u",
+        callable_info.callable_line_entry.file.GetFilename().GetCString(),
+        callable_info.callable_line_entry.line);
+    break;
+  case CPPLanguageRuntime::LibCppStdFunctionCallableCase::CallableObject:
+    stream.Printf(
+        " Function in File %s at Line %u",
+        callable_info.callable_line_entry.file.GetFilename().GetCString(),
+        callable_info.callable_line_entry.line);
+    break;
+  case CPPLanguageRuntime::LibCppStdFunctionCallableCase::FreeOrMemberFunction:
+    stream.Printf(" Function = %s ",
+                  callable_info.callable_symbol.GetName().GetCString());
+    break;
+  }
+
+  return true;
+}
+
+bool lldb_private::formatters::LibcxxSmartPointerSummaryProvider(
+    ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
+  ValueObjectSP valobj_sp(valobj.GetNonSyntheticValue());
+  if (!valobj_sp)
+    return false;
+  ValueObjectSP ptr_sp(
+      valobj_sp->GetChildMemberWithName(ConstString("__ptr_"), true));
+  ValueObjectSP count_sp(valobj_sp->GetChildAtNamePath(
+      {ConstString("__cntrl_"), ConstString("__shared_owners_")}));
+  ValueObjectSP weakcount_sp(valobj_sp->GetChildAtNamePath(
+      {ConstString("__cntrl_"), ConstString("__shared_weak_owners_")}));
+
+  if (!ptr_sp)
+    return false;
+
+  if (ptr_sp->GetValueAsUnsigned(0) == 0) {
+    stream.Printf("nullptr");
+    return true;
+  } else {
+    bool print_pointee = false;
+    Status error;
+    ValueObjectSP pointee_sp = ptr_sp->Dereference(error);
+    if (pointee_sp && error.Success()) {
+      if (pointee_sp->DumpPrintableRepresentation(
+              stream, ValueObject::eValueObjectRepresentationStyleSummary,
+              lldb::eFormatInvalid,
+              ValueObject::PrintableRepresentationSpecialCases::eDisable,
+              false))
+        print_pointee = true;
+    }
+    if (!print_pointee)
+      stream.Printf("ptr = 0x%" PRIx64, ptr_sp->GetValueAsUnsigned(0));
+  }
+
+  if (count_sp)
+    stream.Printf(" strong=%" PRIu64, 1 + count_sp->GetValueAsUnsigned(0));
+
+  if (weakcount_sp)
+    stream.Printf(" weak=%" PRIu64, 1 + weakcount_sp->GetValueAsUnsigned(0));
+
+  return true;
+}
+
+/*
+ (lldb) fr var ibeg --raw --ptr-depth 1
+ (std::__1::__map_iterator<std::__1::__tree_iterator<std::__1::pair<int,
+ std::__1::basic_string<char, std::__1::char_traits<char>,
+ std::__1::allocator<char> > >, std::__1::__tree_node<std::__1::pair<int,
+ std::__1::basic_string<char, std::__1::char_traits<char>,
+ std::__1::allocator<char> > >, void *> *, long> >) ibeg = {
+ __i_ = {
+ __ptr_ = 0x0000000100103870 {
+ std::__1::__tree_node_base<void *> = {
+ std::__1::__tree_end_node<std::__1::__tree_node_base<void *> *> = {
+ __left_ = 0x0000000000000000
+ }
+ __right_ = 0x0000000000000000
+ __parent_ = 0x00000001001038b0
+ __is_black_ = true
+ }
+ __value_ = {
+ first = 0
+ second = { std::string }
+ */
+
+lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
+    LibCxxMapIteratorSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
+    : SyntheticChildrenFrontEnd(*valobj_sp), m_pair_ptr(), m_pair_sp() {
+  if (valobj_sp)
+    Update();
+}
+
+bool lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::Update() {
+  m_pair_sp.reset();
+  m_pair_ptr = nullptr;
+
+  ValueObjectSP valobj_sp = m_backend.GetSP();
+  if (!valobj_sp)
+    return false;
+
+  TargetSP target_sp(valobj_sp->GetTargetSP());
+
+  if (!target_sp)
+    return false;
+
+  if (!valobj_sp)
+    return false;
+
+  static ConstString g___i_("__i_");
+
+  // this must be a ValueObject* because it is a child of the ValueObject we
+  // are producing children for it if were a ValueObjectSP, we would end up
+  // with a loop (iterator -> synthetic -> child -> parent == iterator) and
+  // that would in turn leak memory by never allowing the ValueObjects to die
+  // and free their memory
+  m_pair_ptr = valobj_sp
+                   ->GetValueForExpressionPath(
+                       ".__i_.__ptr_->__value_", nullptr, nullptr,
+                       ValueObject::GetValueForExpressionPathOptions()
+                           .DontCheckDotVsArrowSyntax()
+                           .SetSyntheticChildrenTraversal(
+                               ValueObject::GetValueForExpressionPathOptions::
+                                   SyntheticChildrenTraversal::None),
+                       nullptr)
+                   .get();
+
+  if (!m_pair_ptr) {
+    m_pair_ptr = valobj_sp
+                     ->GetValueForExpressionPath(
+                         ".__i_.__ptr_", nullptr, nullptr,
+                         ValueObject::GetValueForExpressionPathOptions()
+                             .DontCheckDotVsArrowSyntax()
+                             .SetSyntheticChildrenTraversal(
+                                 ValueObject::GetValueForExpressionPathOptions::
+                                     SyntheticChildrenTraversal::None),
+                         nullptr)
+                     .get();
+    if (m_pair_ptr) {
+      auto __i_(valobj_sp->GetChildMemberWithName(g___i_, true));
+      if (!__i_) {
+        m_pair_ptr = nullptr;
+        return false;
+      }
+      CompilerType pair_type(
+          __i_->GetCompilerType().GetTypeTemplateArgument(0));
+      std::string name;
+      uint64_t bit_offset_ptr;
+      uint32_t bitfield_bit_size_ptr;
+      bool is_bitfield_ptr;
+      pair_type = pair_type.GetFieldAtIndex(
+          0, name, &bit_offset_ptr, &bitfield_bit_size_ptr, &is_bitfield_ptr);
+      if (!pair_type) {
+        m_pair_ptr = nullptr;
+        return false;
+      }
+
+      auto addr(m_pair_ptr->GetValueAsUnsigned(LLDB_INVALID_ADDRESS));
+      m_pair_ptr = nullptr;
+      if (addr && addr != LLDB_INVALID_ADDRESS) {
+        ClangASTContext *ast_ctx =
+            llvm::dyn_cast_or_null<ClangASTContext>(pair_type.GetTypeSystem());
+        if (!ast_ctx)
+          return false;
+        CompilerType tree_node_type = ast_ctx->CreateStructForIdentifier(
+            ConstString(),
+            {{"ptr0",
+              ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
+             {"ptr1",
+              ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
+             {"ptr2",
+              ast_ctx->GetBasicType(lldb::eBasicTypeVoid).GetPointerType()},
+             {"cw", ast_ctx->GetBasicType(lldb::eBasicTypeBool)},
+             {"payload", pair_type}});
+        llvm::Optional<uint64_t> size = tree_node_type.GetByteSize(nullptr);
+        if (!size)
+          return false;
+        DataBufferSP buffer_sp(new DataBufferHeap(*size, 0));
+        ProcessSP process_sp(target_sp->GetProcessSP());
+        Status error;
+        process_sp->ReadMemory(addr, buffer_sp->GetBytes(),
+                               buffer_sp->GetByteSize(), error);
+        if (error.Fail())
+          return false;
+        DataExtractor extractor(buffer_sp, process_sp->GetByteOrder(),
+                                process_sp->GetAddressByteSize());
+        auto pair_sp = CreateValueObjectFromData(
+            "pair", extractor, valobj_sp->GetExecutionContextRef(),
+            tree_node_type);
+        if (pair_sp)
+          m_pair_sp = pair_sp->GetChildAtIndex(4, true);
+      }
+    }
+  }
+
+  return false;
+}
+
+size_t lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
+    CalculateNumChildren() {
+  return 2;
+}
+
+lldb::ValueObjectSP
+lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::GetChildAtIndex(
+    size_t idx) {
+  if (m_pair_ptr)
+    return m_pair_ptr->GetChildAtIndex(idx, true);
+  if (m_pair_sp)
+    return m_pair_sp->GetChildAtIndex(idx, true);
+  return lldb::ValueObjectSP();
+}
+
+bool lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
+    MightHaveChildren() {
+  return true;
+}
+
+size_t lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
+    GetIndexOfChildWithName(ConstString name) {
+  if (name == "first")
+    return 0;
+  if (name == "second")
+    return 1;
+  return UINT32_MAX;
+}
+
+lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
+    ~LibCxxMapIteratorSyntheticFrontEnd() {
+  // this will be deleted when its parent dies (since it's a child object)
+  // delete m_pair_ptr;
+}
+
+SyntheticChildrenFrontEnd *
+lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEndCreator(
+    CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
+  return (valobj_sp ? new LibCxxMapIteratorSyntheticFrontEnd(valobj_sp)
+                    : nullptr);
+}
+
+/*
+ (lldb) fr var ibeg --raw --ptr-depth 1 -T
+ (std::__1::__wrap_iter<int *>) ibeg = {
+ (std::__1::__wrap_iter<int *>::iterator_type) __i = 0x00000001001037a0 {
+ (int) *__i = 1
+ }
+ }
+*/
+
+SyntheticChildrenFrontEnd *
+lldb_private::formatters::LibCxxVectorIteratorSyntheticFrontEndCreator(
+    CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
+  static ConstString g_item_name;
+  if (!g_item_name)
+    g_item_name.SetCString("__i");
+  return (valobj_sp
+              ? new VectorIteratorSyntheticFrontEnd(valobj_sp, g_item_name)
+              : nullptr);
+}
+
+lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
+    LibcxxSharedPtrSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
+    : SyntheticChildrenFrontEnd(*valobj_sp), m_cntrl(nullptr), m_count_sp(),
+      m_weak_count_sp(), m_ptr_size(0), m_byte_order(lldb::eByteOrderInvalid) {
+  if (valobj_sp)
+    Update();
+}
+
+size_t lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
+    CalculateNumChildren() {
+  return (m_cntrl ? 1 : 0);
+}
+
+lldb::ValueObjectSP
+lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::GetChildAtIndex(
+    size_t idx) {
+  if (!m_cntrl)
+    return lldb::ValueObjectSP();
+
+  ValueObjectSP valobj_sp = m_backend.GetSP();
+  if (!valobj_sp)
+    return lldb::ValueObjectSP();
+
+  if (idx == 0)
+    return valobj_sp->GetChildMemberWithName(ConstString("__ptr_"), true);
+
+  if (idx > 2)
+    return lldb::ValueObjectSP();
+
+  if (idx == 1) {
+    if (!m_count_sp) {
+      ValueObjectSP shared_owners_sp(m_cntrl->GetChildMemberWithName(
+          ConstString("__shared_owners_"), true));
+      if (!shared_owners_sp)
+        return lldb::ValueObjectSP();
+      uint64_t count = 1 + shared_owners_sp->GetValueAsUnsigned(0);
+      DataExtractor data(&count, 8, m_byte_order, m_ptr_size);
+      m_count_sp = CreateValueObjectFromData(
+          "count", data, valobj_sp->GetExecutionContextRef(),
+          shared_owners_sp->GetCompilerType());
+    }
+    return m_count_sp;
+  } else /* if (idx == 2) */
+  {
+    if (!m_weak_count_sp) {
+      ValueObjectSP shared_weak_owners_sp(m_cntrl->GetChildMemberWithName(
+          ConstString("__shared_weak_owners_"), true));
+      if (!shared_weak_owners_sp)
+        return lldb::ValueObjectSP();
+      uint64_t count = 1 + shared_weak_owners_sp->GetValueAsUnsigned(0);
+      DataExtractor data(&count, 8, m_byte_order, m_ptr_size);
+      m_weak_count_sp = CreateValueObjectFromData(
+          "count", data, valobj_sp->GetExecutionContextRef(),
+          shared_weak_owners_sp->GetCompilerType());
+    }
+    return m_weak_count_sp;
+  }
+}
+
+bool lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::Update() {
+  m_count_sp.reset();
+  m_weak_count_sp.reset();
+  m_cntrl = nullptr;
+
+  ValueObjectSP valobj_sp = m_backend.GetSP();
+  if (!valobj_sp)
+    return false;
+
+  TargetSP target_sp(valobj_sp->GetTargetSP());
+  if (!target_sp)
+    return false;
+
+  m_byte_order = target_sp->GetArchitecture().GetByteOrder();
+  m_ptr_size = target_sp->GetArchitecture().GetAddressByteSize();
+
+  lldb::ValueObjectSP cntrl_sp(
+      valobj_sp->GetChildMemberWithName(ConstString("__cntrl_"), true));
+
+  m_cntrl = cntrl_sp.get(); // need to store the raw pointer to avoid a circular
+                            // dependency
+  return false;
+}
+
+bool lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
+    MightHaveChildren() {
+  return true;
+}
+
+size_t lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
+    GetIndexOfChildWithName(ConstString name) {
+  if (name == "__ptr_")
+    return 0;
+  if (name == "count")
+    return 1;
+  if (name == "weak_count")
+    return 2;
+  return UINT32_MAX;
+}
+
+lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
+    ~LibcxxSharedPtrSyntheticFrontEnd() = default;
+
+SyntheticChildrenFrontEnd *
+lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEndCreator(
+    CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
+  return (valobj_sp ? new LibcxxSharedPtrSyntheticFrontEnd(valobj_sp)
+                    : nullptr);
+}
+
+bool lldb_private::formatters::LibcxxContainerSummaryProvider(
+    ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
+  if (valobj.IsPointerType()) {
+    uint64_t value = valobj.GetValueAsUnsigned(0);
+    if (!value)
+      return false;
+    stream.Printf("0x%016" PRIx64 " ", value);
+  }
+  return FormatEntity::FormatStringRef("size=${svar%#}", stream, nullptr,
+                                       nullptr, nullptr, &valobj, false, false);
+}
+
+// the field layout in a libc++ string (cap, side, data or data, size, cap)
+enum LibcxxStringLayoutMode {
+  eLibcxxStringLayoutModeCSD = 0,
+  eLibcxxStringLayoutModeDSC = 1,
+  eLibcxxStringLayoutModeInvalid = 0xffff
+};
+
+// this function abstracts away the layout and mode details of a libc++ string
+// and returns the address of the data and the size ready for callers to
+// consume
+static bool ExtractLibcxxStringInfo(ValueObject &valobj,
+                                    ValueObjectSP &location_sp,
+                                    uint64_t &size) {
+  ValueObjectSP D(valobj.GetChildAtIndexPath({0, 0, 0, 0}));
+  if (!D)
+    return false;
+
+  ValueObjectSP layout_decider(
+    D->GetChildAtIndexPath(llvm::ArrayRef<size_t>({0, 0})));
+
+  // this child should exist
+  if (!layout_decider)
+    return false;
+
+  ConstString g_data_name("__data_");
+  ConstString g_size_name("__size_");
+  bool short_mode = false; // this means the string is in short-mode and the
+                           // data is stored inline
+  LibcxxStringLayoutMode layout = (layout_decider->GetName() == g_data_name)
+                                      ? eLibcxxStringLayoutModeDSC
+                                      : eLibcxxStringLayoutModeCSD;
+  uint64_t size_mode_value = 0;
+
+  if (layout == eLibcxxStringLayoutModeDSC) {
+    ValueObjectSP size_mode(D->GetChildAtIndexPath({1, 1, 0}));
+    if (!size_mode)
+      return false;
+
+    if (size_mode->GetName() != g_size_name) {
+      // we are hitting the padding structure, move along
+      size_mode = D->GetChildAtIndexPath({1, 1, 1});
+      if (!size_mode)
+        return false;
+    }
+
+    size_mode_value = (size_mode->GetValueAsUnsigned(0));
+    short_mode = ((size_mode_value & 0x80) == 0);
+  } else {
+    ValueObjectSP size_mode(D->GetChildAtIndexPath({1, 0, 0}));
+    if (!size_mode)
+      return false;
+
+    size_mode_value = (size_mode->GetValueAsUnsigned(0));
+    short_mode = ((size_mode_value & 1) == 0);
+  }
+
+  if (short_mode) {
+    ValueObjectSP s(D->GetChildAtIndex(1, true));
+    if (!s)
+      return false;
+    location_sp = s->GetChildAtIndex(
+        (layout == eLibcxxStringLayoutModeDSC) ? 0 : 1, true);
+    size = (layout == eLibcxxStringLayoutModeDSC)
+               ? size_mode_value
+               : ((size_mode_value >> 1) % 256);
+    return (location_sp.get() != nullptr);
+  } else {
+    ValueObjectSP l(D->GetChildAtIndex(0, true));
+    if (!l)
+      return false;
+    // we can use the layout_decider object as the data pointer
+    location_sp = (layout == eLibcxxStringLayoutModeDSC)
+                      ? layout_decider
+                      : l->GetChildAtIndex(2, true);
+    ValueObjectSP size_vo(l->GetChildAtIndex(1, true));
+    if (!size_vo || !location_sp)
+      return false;
+    size = size_vo->GetValueAsUnsigned(0);
+    return true;
+  }
+}
+
+bool lldb_private::formatters::LibcxxWStringSummaryProvider(
+    ValueObject &valobj, Stream &stream,
+    const TypeSummaryOptions &summary_options) {
+  uint64_t size = 0;
+  ValueObjectSP location_sp;
+  if (!ExtractLibcxxStringInfo(valobj, location_sp, size))
+    return false;
+  if (size == 0) {
+    stream.Printf("L\"\"");
+    return true;
+  }
+  if (!location_sp)
+    return false;
+
+  DataExtractor extractor;
+
+  StringPrinter::ReadBufferAndDumpToStreamOptions options(valobj);
+
+  if (summary_options.GetCapping() == TypeSummaryCapping::eTypeSummaryCapped) {
+    const auto max_size = valobj.GetTargetSP()->GetMaximumSizeOfStringSummary();
+    if (size > max_size) {
+      size = max_size;
+      options.SetIsTruncated(true);
+    }
+  }
+  location_sp->GetPointeeData(extractor, 0, size);
+
+  // std::wstring::size() is measured in 'characters', not bytes
+  auto wchar_t_size = valobj.GetTargetSP()
+                          ->GetScratchClangASTContext()
+                          ->GetBasicType(lldb::eBasicTypeWChar)
+                          .GetByteSize(nullptr);
+  if (!wchar_t_size)
+    return false;
+
+  options.SetData(extractor);
+  options.SetStream(&stream);
+  options.SetPrefixToken("L");
+  options.SetQuote('"');
+  options.SetSourceSize(size);
+  options.SetBinaryZeroIsTerminator(false);
+
+  switch (*wchar_t_size) {
+  case 1:
+    StringPrinter::ReadBufferAndDumpToStream<
+        lldb_private::formatters::StringPrinter::StringElementType::UTF8>(
+        options);
+    break;
+
+  case 2:
+    lldb_private::formatters::StringPrinter::ReadBufferAndDumpToStream<
+        lldb_private::formatters::StringPrinter::StringElementType::UTF16>(
+        options);
+    break;
+
+  case 4:
+    lldb_private::formatters::StringPrinter::ReadBufferAndDumpToStream<
+        lldb_private::formatters::StringPrinter::StringElementType::UTF32>(
+        options);
+    break;
+
+  default:
+    stream.Printf("size for wchar_t is not valid");
+    return true;
+  }
+
+  return true;
+}
+
+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;
+
+  if (!ExtractLibcxxStringInfo(valobj, location_sp, size))
+    return false;
+
+  if (size == 0) {
+    stream.Printf("\"\"");
+    return true;
+  }
+
+  if (!location_sp)
+    return false;
+
+  StringPrinter::ReadBufferAndDumpToStreamOptions options(valobj);
+
+  DataExtractor extractor;
+  if (summary_options.GetCapping() == TypeSummaryCapping::eTypeSummaryCapped) {
+    const auto max_size = valobj.GetTargetSP()->GetMaximumSizeOfStringSummary();
+    if (size > max_size) {
+      size = max_size;
+      options.SetIsTruncated(true);
+    }
+  }
+  location_sp->GetPointeeData(extractor, 0, size);
+
+  options.SetData(extractor);
+  options.SetStream(&stream);
+
+  if (prefix_token.empty())
+    options.SetPrefixToken(nullptr);
+  else
+    options.SetPrefixToken(prefix_token);
+
+  options.SetQuote('"');
+  options.SetSourceSize(size);
+  options.SetBinaryZeroIsTerminator(false);
+  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");
+}