Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release:

MFC r309142 (by emaste):

Add WITH_LLD_AS_LD build knob

If set it installs LLD as /usr/bin/ld.  LLD (as of version 3.9) is not
capable of linking the world and kernel, but can self-host and link many
substantial applications. GNU ld continues to be used for the world and
kernel build, regardless of how this knob is set.

It is on by default for arm64, and off for all other CPU architectures.

Sponsored by:	The FreeBSD Foundation

MFC r310840:

Reapply 310775, now it also builds correctly if lldb is disabled:

Move llvm-objdump from CLANG_EXTRAS to installed by default

We currently install three tools from binutils 2.17.50: as, ld, and
objdump. Work is underway to migrate to a permissively-licensed
tool-chain, with one goal being the retirement of binutils 2.17.50.

LLVM's llvm-objdump is intended to be compatible with GNU objdump
although it is currently missing some options and may have formatting
differences. Enable it by default for testing and further investigation.
It may later be changed to install as /usr/bin/objdump, it becomes a
fully viable replacement.

Reviewed by:	emaste
Differential Revision:	https://reviews.freebsd.org/D8879

MFC r312855 (by emaste):

Rename LLD_AS_LD to LLD_IS_LD, for consistency with CLANG_IS_CC

Reported by:	Dan McGregor <dan.mcgregor usask.ca>

MFC r313559 | glebius | 2017-02-10 18:34:48 +0100 (Fri, 10 Feb 2017) | 5 lines

Don't check struct rtentry on FreeBSD, it is an internal kernel structure.
On other systems it may be API structure for SIOCADDRT/SIOCDELRT.

Reviewed by:	emaste, dim

MFC r314152 (by jkim):

Remove an assembler flag, which is redundant since r309124.  The upstream
took care of it by introducing a macro NO_EXEC_STACK_DIRECTIVE.

http://llvm.org/viewvc/llvm-project?rev=273500&view=rev

Reviewed by:	dim

MFC r314564:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
4.0.0 (branches/release_40 296509).  The release will follow soon.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Also note that as of 4.0.0, lld should be able to link the base system
on amd64 and aarch64.  See the WITH_LLD_IS_LLD setting in src.conf(5).
Though please be aware that this is work in progress.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/4.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Jan Beich, Antoine Brodin and Eric Fiselier for
their help.

Relnotes:	yes
Exp-run:	antoine
PR:		215969, 216008

MFC r314708:

For now, revert r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

This commit is the cause of excessive compile times on skein_block.c
(and possibly other files) during kernel builds on amd64.

We never saw the problematic behavior described in this upstream commit,
so for now it is better to revert it.  An upstream bug has been filed
here: https://bugs.llvm.org/show_bug.cgi?id=32142

Reported by:	mjg

MFC r314795:

Reapply r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

Pull in r296992 from upstream llvm trunk (by Sanjoy Das):

  [SCEV] Decrease the recursion threshold for CompareValueComplexity

  Fixes PR32142.

  r287232 accidentally increased the recursion threshold for
  CompareValueComplexity from 2 to 32.  This change reverses that
  change by introducing a separate flag for CompareValueComplexity's
  threshold.

The latter revision fixes the excessive compile times for skein_block.c.

MFC r314907 | mmel | 2017-03-08 12:40:27 +0100 (Wed, 08 Mar 2017) | 7 lines

Unbreak ARMv6 world.

The new compiler_rt library imported with clang 4.0.0 have several fatal
issues (non-functional __udivsi3 for example) with ARM specific instrict
functions. As temporary workaround, until upstream solve these problems,
disable all thumb[1][2] related feature.

MFC r315016:

Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release.
We were already very close to the last release candidate, so this is a
pretty minor update.

Relnotes:	yes

MFC r316005:

Revert r314907, and pull in r298713 from upstream compiler-rt trunk (by
Weiming Zhao):

  builtins: Select correct code fragments when compiling for Thumb1/Thum2/ARM ISA.

  Summary:
  Value of __ARM_ARCH_ISA_THUMB isn't based on the actual compilation
  mode (-mthumb, -marm), it reflect's capability of given CPU.

  Due to this:
   - use  __tbumb__ and __thumb2__ insteand of __ARM_ARCH_ISA_THUMB
   - use '.thumb' directive consistently  in all affected files
   - decorate all thumb functions using
     DEFINE_COMPILERRT_THUMB_FUNCTION()

  ---------
  Note: This patch doesn't fix broken Thumb1 variant of __udivsi3 !

  Reviewers: weimingz, rengolin, compnerd

  Subscribers: aemerson, dim

  Differential Revision: https://reviews.llvm.org/D30938

Discussed with:	mmel

1 files changed, 586 insertions, 497 deletions

diff --git a/contrib/llvm/tools/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp b/contrib/llvm/tools/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
index beb89b8..82441a6 100644
--- a/contrib/llvm/tools/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
+++ b/contrib/llvm/tools/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
@@ -27,202 +27,211 @@
 #include "lldb/Host/Endian.h"
 #include "lldb/Symbol/ClangASTContext.h"
 #include "lldb/Target/Target.h"
+#include "lldb/Utility/ProcessStructReader.h"
 
 using namespace lldb;
 using namespace lldb_private;
 using namespace lldb_private::formatters;
 
-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;
-        Error error;
-        ValueObjectSP pointee_sp = ptr_sp->Dereference(error);
-        if (pointee_sp && error.Success())
-        {
-            if (pointee_sp->DumpPrintableRepresentation(stream,
-                                                        ValueObject::eValueObjectRepresentationStyleSummary,
-                                                        lldb::eFormatInvalid,
-                                                        ValueObject::ePrintableRepresentationSpecialCasesDisable,
-                                                        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));
+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 (weakcount_sp)
-        stream.Printf(" weak=%" PRIu64, 1+weakcount_sp->GetValueAsUnsigned(0));
-    
+  if (ptr_sp->GetValueAsUnsigned(0) == 0) {
+    stream.Printf("nullptr");
     return true;
+  } else {
+    bool print_pointee = false;
+    Error 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_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::LibcxxVectorBoolSyntheticFrontEnd (lldb::ValueObjectSP valobj_sp) :
-    SyntheticChildrenFrontEnd(*valobj_sp),
-    m_bool_type(),
-    m_exe_ctx_ref(),
-    m_count(0),
-    m_base_data_address(0),
-    m_children()
-{
-    if (valobj_sp)
-    {
-        Update();
-        m_bool_type = valobj_sp->GetCompilerType().GetBasicTypeFromAST(lldb::eBasicTypeBool);
-    }
+lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
+    LibcxxVectorBoolSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
+    : SyntheticChildrenFrontEnd(*valobj_sp), m_bool_type(), m_exe_ctx_ref(),
+      m_count(0), m_base_data_address(0), m_children() {
+  if (valobj_sp) {
+    Update();
+    m_bool_type =
+        valobj_sp->GetCompilerType().GetBasicTypeFromAST(lldb::eBasicTypeBool);
+  }
 }
 
-size_t
-lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::CalculateNumChildren ()
-{
-    return m_count;
+size_t lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
+    CalculateNumChildren() {
+  return m_count;
 }
 
 lldb::ValueObjectSP
-lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::GetChildAtIndex (size_t idx)
-{
-    auto iter = m_children.find(idx),
-        end = m_children.end();
-    if (iter != end)
-        return iter->second;
-    if (idx >= m_count)
-        return ValueObjectSP();
-    if (m_base_data_address == 0 || m_count == 0)
-        return ValueObjectSP();
-    if (!m_bool_type)
-        return ValueObjectSP();
-    size_t byte_idx = (idx >> 3); // divide by 8 to get byte index
-    size_t bit_index = (idx & 7); // efficient idx % 8 for bit index
-    lldb::addr_t byte_location = m_base_data_address + byte_idx;
-    ProcessSP process_sp(m_exe_ctx_ref.GetProcessSP());
-    if (!process_sp)
-        return ValueObjectSP();
-    uint8_t byte = 0;
-    uint8_t mask = 0;
-    Error err;
-    size_t bytes_read = process_sp->ReadMemory(byte_location, &byte, 1, err);
-    if (err.Fail() || bytes_read == 0)
-        return ValueObjectSP();
-    switch (bit_index)
-    {
-        case 0:
-            mask = 1; break;
-        case 1:
-            mask = 2; break;
-        case 2:
-            mask = 4; break;
-        case 3:
-            mask = 8; break;
-        case 4:
-            mask = 16; break;
-        case 5:
-            mask = 32; break;
-        case 6:
-            mask = 64; break;
-        case 7:
-            mask = 128; break;
-        default:
-            return ValueObjectSP();
-    }
-    bool bit_set = ((byte & mask) != 0);
-    DataBufferSP buffer_sp(new DataBufferHeap(m_bool_type.GetByteSize(nullptr), 0));
-    if (bit_set && buffer_sp && buffer_sp->GetBytes())
-        *(buffer_sp->GetBytes()) = 1; // regardless of endianness, anything non-zero is true
-    StreamString name; name.Printf("[%" PRIu64 "]", (uint64_t)idx);
-    ValueObjectSP retval_sp(CreateValueObjectFromData(name.GetData(), DataExtractor(buffer_sp, process_sp->GetByteOrder(), process_sp->GetAddressByteSize()), m_exe_ctx_ref, m_bool_type));
-    if (retval_sp)
-        m_children[idx] = retval_sp;
-    return retval_sp;
+lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::GetChildAtIndex(
+    size_t idx) {
+  auto iter = m_children.find(idx), end = m_children.end();
+  if (iter != end)
+    return iter->second;
+  if (idx >= m_count)
+    return ValueObjectSP();
+  if (m_base_data_address == 0 || m_count == 0)
+    return ValueObjectSP();
+  if (!m_bool_type)
+    return ValueObjectSP();
+  size_t byte_idx = (idx >> 3); // divide by 8 to get byte index
+  size_t bit_index = (idx & 7); // efficient idx % 8 for bit index
+  lldb::addr_t byte_location = m_base_data_address + byte_idx;
+  ProcessSP process_sp(m_exe_ctx_ref.GetProcessSP());
+  if (!process_sp)
+    return ValueObjectSP();
+  uint8_t byte = 0;
+  uint8_t mask = 0;
+  Error err;
+  size_t bytes_read = process_sp->ReadMemory(byte_location, &byte, 1, err);
+  if (err.Fail() || bytes_read == 0)
+    return ValueObjectSP();
+  switch (bit_index) {
+  case 0:
+    mask = 1;
+    break;
+  case 1:
+    mask = 2;
+    break;
+  case 2:
+    mask = 4;
+    break;
+  case 3:
+    mask = 8;
+    break;
+  case 4:
+    mask = 16;
+    break;
+  case 5:
+    mask = 32;
+    break;
+  case 6:
+    mask = 64;
+    break;
+  case 7:
+    mask = 128;
+    break;
+  default:
+    return ValueObjectSP();
+  }
+  bool bit_set = ((byte & mask) != 0);
+  DataBufferSP buffer_sp(
+      new DataBufferHeap(m_bool_type.GetByteSize(nullptr), 0));
+  if (bit_set && buffer_sp && buffer_sp->GetBytes())
+    *(buffer_sp->GetBytes()) =
+        1; // regardless of endianness, anything non-zero is true
+  StreamString name;
+  name.Printf("[%" PRIu64 "]", (uint64_t)idx);
+  ValueObjectSP retval_sp(CreateValueObjectFromData(
+      name.GetString(), DataExtractor(buffer_sp, process_sp->GetByteOrder(),
+                                      process_sp->GetAddressByteSize()),
+      m_exe_ctx_ref, m_bool_type));
+  if (retval_sp)
+    m_children[idx] = retval_sp;
+  return retval_sp;
 }
 
 /*(std::__1::vector<std::__1::allocator<bool> >) vBool = {
  __begin_ = 0x00000001001000e0
  __size_ = 56
  __cap_alloc_ = {
- std::__1::__libcpp_compressed_pair_imp<unsigned long, std::__1::allocator<unsigned long> > = {
+ std::__1::__libcpp_compressed_pair_imp<unsigned long,
+ std::__1::allocator<unsigned long> > = {
  __first_ = 1
  }
  }
  }*/
 
-bool
-lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::Update()
-{
-    m_children.clear();
-    ValueObjectSP valobj_sp = m_backend.GetSP();
-    if (!valobj_sp)
-        return false;
-    m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
-    ValueObjectSP size_sp(valobj_sp->GetChildMemberWithName(ConstString("__size_"), true));
-    if (!size_sp)
-        return false;
-    m_count = size_sp->GetValueAsUnsigned(0);
-    if (!m_count)
-        return true;
-    ValueObjectSP begin_sp(valobj_sp->GetChildMemberWithName(ConstString("__begin_"), true));
-    if (!begin_sp)
-    {
-        m_count = 0;
-        return false;
-    }
-    m_base_data_address = begin_sp->GetValueAsUnsigned(0);
-    if (!m_base_data_address)
-    {
-        m_count = 0;
-        return false;
-    }
+bool lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::Update() {
+  m_children.clear();
+  ValueObjectSP valobj_sp = m_backend.GetSP();
+  if (!valobj_sp)
     return false;
+  m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
+  ValueObjectSP size_sp(
+      valobj_sp->GetChildMemberWithName(ConstString("__size_"), true));
+  if (!size_sp)
+    return false;
+  m_count = size_sp->GetValueAsUnsigned(0);
+  if (!m_count)
+    return true;
+  ValueObjectSP begin_sp(
+      valobj_sp->GetChildMemberWithName(ConstString("__begin_"), true));
+  if (!begin_sp) {
+    m_count = 0;
+    return false;
+  }
+  m_base_data_address = begin_sp->GetValueAsUnsigned(0);
+  if (!m_base_data_address) {
+    m_count = 0;
+    return false;
+  }
+  return false;
 }
 
-bool
-lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::MightHaveChildren ()
-{
-    return true;
+bool lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
+    MightHaveChildren() {
+  return true;
 }
 
-size_t
-lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::GetIndexOfChildWithName (const ConstString &name)
-{
-    if (!m_count || !m_base_data_address)
-        return UINT32_MAX;
-    const char* item_name = name.GetCString();
-    uint32_t idx = ExtractIndexFromString(item_name);
-    if (idx < UINT32_MAX && idx >= CalculateNumChildren())
-        return UINT32_MAX;
-    return idx;
+size_t lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
+    GetIndexOfChildWithName(const ConstString &name) {
+  if (!m_count || !m_base_data_address)
+    return UINT32_MAX;
+  const char *item_name = name.GetCString();
+  uint32_t idx = ExtractIndexFromString(item_name);
+  if (idx < UINT32_MAX && idx >= CalculateNumChildren())
+    return UINT32_MAX;
+  return idx;
 }
 
-lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::~LibcxxVectorBoolSyntheticFrontEnd() = default;
+lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
+    ~LibcxxVectorBoolSyntheticFrontEnd() = default;
 
-SyntheticChildrenFrontEnd*
-lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEndCreator (CXXSyntheticChildren*, lldb::ValueObjectSP valobj_sp)
-{
-    return (valobj_sp ? new LibcxxVectorBoolSyntheticFrontEnd(valobj_sp) : nullptr);
+SyntheticChildrenFrontEnd *
+lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEndCreator(
+    CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
+  return (valobj_sp ? new LibcxxVectorBoolSyntheticFrontEnd(valobj_sp)
+                    : nullptr);
 }
 
 /*
  (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 = {
+ (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 *> = {
@@ -238,82 +247,144 @@ lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEndCreator (CXXSynthetic
  second = { std::string }
  */
 
-lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::LibCxxMapIteratorSyntheticFrontEnd (lldb::ValueObjectSP valobj_sp) :
-    SyntheticChildrenFrontEnd(*valobj_sp),
-    m_pair_ptr()
-{
-    if (valobj_sp)
-        Update();
+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()
-{
-    ValueObjectSP valobj_sp = m_backend.GetSP();
-    if (!valobj_sp)
-        return false;
-    
-    TargetSP target_sp(valobj_sp->GetTargetSP());
-    
-    if (!target_sp)
-        return false;
+bool lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::Update() {
+  m_pair_sp.reset();
+  m_pair_ptr = nullptr;
 
-    if (!valobj_sp)
-        return false;
+  ValueObjectSP valobj_sp = m_backend.GetSP();
+  if (!valobj_sp)
+    return false;
+
+  TargetSP target_sp(valobj_sp->GetTargetSP());
 
-    // 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,
-                                                      nullptr,
-                                                      ValueObject::GetValueForExpressionPathOptions().DontCheckDotVsArrowSyntax().SetSyntheticChildrenTraversal(ValueObject::GetValueForExpressionPathOptions::SyntheticChildrenTraversal::None),
-                                                      nullptr).get();
-    
+  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));
+      lldb::TemplateArgumentKind kind;
+      if (!__i_) {
+        m_pair_ptr = nullptr;
+        return false;
+      }
+      CompilerType pair_type(__i_->GetCompilerType().GetTemplateArgument(0, kind));
+      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}
+        });
+        DataBufferSP buffer_sp(new DataBufferHeap(tree_node_type.GetByteSize(nullptr),0));
+        ProcessSP process_sp(target_sp->GetProcessSP());
+        Error 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;
+size_t lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
+    CalculateNumChildren() {
+  return 2;
 }
 
 lldb::ValueObjectSP
-lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::GetChildAtIndex (size_t idx)
-{
-    if (!m_pair_ptr)
-        return 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;
+bool lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
+    MightHaveChildren() {
+  return true;
 }
 
-size_t
-lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::GetIndexOfChildWithName (const ConstString &name)
-{
-    if (name == ConstString("first"))
-        return 0;
-    if (name == ConstString("second"))
-        return 1;
-    return UINT32_MAX;
+size_t lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEnd::
+    GetIndexOfChildWithName(const ConstString &name) {
+  if (name == ConstString("first"))
+    return 0;
+  if (name == ConstString("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;
+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);
+SyntheticChildrenFrontEnd *
+lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEndCreator(
+    CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
+  return (valobj_sp ? new LibCxxMapIteratorSyntheticFrontEnd(valobj_sp)
+                    : nullptr);
 }
 
 /*
@@ -325,323 +396,341 @@ lldb_private::formatters::LibCxxMapIteratorSyntheticFrontEndCreator (CXXSyntheti
  }
 */
 
-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);
+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();
+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);
+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)
+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();
-
-    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;
+      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());
     }
-    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;
+    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
+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;
+bool lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
+    MightHaveChildren() {
+  return true;
 }
 
-size_t
-lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::GetIndexOfChildWithName (const ConstString &name)
-{
-    if (name == ConstString("__ptr_"))
-        return 0;
-    if (name == ConstString("count"))
-        return 1;
-    if (name == ConstString("weak_count"))
-        return 2;
-    return UINT32_MAX;
+size_t lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
+    GetIndexOfChildWithName(const ConstString &name) {
+  if (name == ConstString("__ptr_"))
+    return 0;
+  if (name == ConstString("count"))
+    return 1;
+  if (name == ConstString("weak_count"))
+    return 2;
+  return UINT32_MAX;
 }
 
-lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::~LibcxxSharedPtrSyntheticFrontEnd() = default;
+lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEnd::
+    ~LibcxxSharedPtrSyntheticFrontEnd() = default;
 
-SyntheticChildrenFrontEnd*
-lldb_private::formatters::LibcxxSharedPtrSyntheticFrontEndCreator (CXXSyntheticChildren*, lldb::ValueObjectSP valobj_sp)
-{
-    return (valobj_sp ? new LibcxxSharedPtrSyntheticFrontEnd(valobj_sp) : nullptr);
+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=${svar%#}", stream, nullptr, nullptr, nullptr, &valobj, false, false);
+bool lldb_private::formatters::LibcxxContainerSummaryProvider(
+    ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
+  if (valobj.IsPointerType()) {
+    uint64_t value = valobj.GetValueAsUnsigned(0);
+    if (!value)
+      return false;
+    stream.Printf("0x%016" PRIx64 " ", value);
+  }
+  return FormatEntity::FormatStringRef("size=${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
+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({0,0}));
-    
-    // this child should exist
-    if (!layout_decider)
+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({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;
-    
-    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;
     }
+
+    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);
-    
-    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;
+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);
+
+  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;
 }
 
-bool
-lldb_private::formatters::LibcxxStringSummaryProvider (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("\"\"");
-        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);
-    options.SetPrefixToken(nullptr);
-    options.SetQuote('"');
-    options.SetSourceSize(size);
-    options.SetBinaryZeroIsTerminator(false);
-    StringPrinter::ReadBufferAndDumpToStream<StringPrinter::StringElementType::ASCII>(options);
-    
+bool lldb_private::formatters::LibcxxStringSummaryProvider(
+    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("\"\"");
     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);
+  options.SetPrefixToken(nullptr);
+  options.SetQuote('"');
+  options.SetSourceSize(size);
+  options.SetBinaryZeroIsTerminator(false);
+  StringPrinter::ReadBufferAndDumpToStream<
+      StringPrinter::StringElementType::ASCII>(options);
+
+  return true;
+}
+
+class LibcxxFunctionFrontEnd : public SyntheticValueProviderFrontEnd {
+public:
+  LibcxxFunctionFrontEnd(ValueObject &backend)
+      : SyntheticValueProviderFrontEnd(backend) {}
+
+  lldb::ValueObjectSP GetSyntheticValue() override {
+    static ConstString g___f_("__f_");
+    return m_backend.GetChildMemberWithName(g___f_, true);
+  }
+};
+
+SyntheticChildrenFrontEnd *
+lldb_private::formatters::LibcxxFunctionFrontEndCreator(
+    CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
+  if (valobj_sp)
+    return new LibcxxFunctionFrontEnd(*valobj_sp);
+  return nullptr;
 }