llvm-project/lldb/source/Plugins/Language/ObjC/NSArray.cpp

//===-- NSArray.cpp ---------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// C Includes
// C++ Includes
// Other libraries and framework includes
#include "clang/AST/ASTContext.h"

// Project includes
#include "Cocoa.h"

#include "Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Core/ValueObjectConstResult.h"
#include "lldb/DataFormatters/FormattersHelpers.h"
#include "lldb/Expression/FunctionCaller.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Target/Language.h"
#include "lldb/Target/ObjCLanguageRuntime.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"

using namespace lldb;
using namespace lldb_private;
using namespace lldb_private::formatters;

namespace lldb_private {
namespace formatters {
std::map<ConstString, CXXFunctionSummaryFormat::Callback> &
NSArray_Additionals::GetAdditionalSummaries() {
  static std::map<ConstString, CXXFunctionSummaryFormat::Callback> g_map;
  return g_map;
}

std::map<ConstString, CXXSyntheticChildren::CreateFrontEndCallback> &
NSArray_Additionals::GetAdditionalSynthetics() {
  static std::map<ConstString, CXXSyntheticChildren::CreateFrontEndCallback>
      g_map;
  return g_map;
}

class NSArrayMSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
public:
  NSArrayMSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);

  ~NSArrayMSyntheticFrontEnd() override = default;

  size_t CalculateNumChildren() override;

  lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;

  bool Update() override = 0;

  bool MightHaveChildren() override;

  size_t GetIndexOfChildWithName(const ConstString &name) override;

protected:
  virtual lldb::addr_t GetDataAddress() = 0;

  virtual uint64_t GetUsedCount() = 0;

  virtual uint64_t GetOffset() = 0;

  virtual uint64_t GetSize() = 0;

  ExecutionContextRef m_exe_ctx_ref;
  uint8_t m_ptr_size;
  CompilerType m_id_type;
};

class NSArrayMSyntheticFrontEnd_109 : public NSArrayMSyntheticFrontEnd {
public:
  NSArrayMSyntheticFrontEnd_109(lldb::ValueObjectSP valobj_sp);

  ~NSArrayMSyntheticFrontEnd_109() override;

  bool Update() override;

protected:
  lldb::addr_t GetDataAddress() override;

  uint64_t GetUsedCount() override;

  uint64_t GetOffset() override;

  uint64_t GetSize() override;

private:
  struct DataDescriptor_32 {
    uint32_t _used;
    uint32_t _priv1 : 2;
    uint32_t _size : 30;
    uint32_t _priv2 : 2;
    uint32_t _offset : 30;
    uint32_t _priv3;
    uint32_t _data;
  };

  struct DataDescriptor_64 {
    uint64_t _used;
    uint64_t _priv1 : 2;
    uint64_t _size : 62;
    uint64_t _priv2 : 2;
    uint64_t _offset : 62;
    uint32_t _priv3;
    uint64_t _data;
  };

  DataDescriptor_32 *m_data_32;
  DataDescriptor_64 *m_data_64;
};

class NSArrayMSyntheticFrontEnd_1010 : public NSArrayMSyntheticFrontEnd {
public:
  NSArrayMSyntheticFrontEnd_1010(lldb::ValueObjectSP valobj_sp);

  ~NSArrayMSyntheticFrontEnd_1010() override;

  bool Update() override;

protected:
  lldb::addr_t GetDataAddress() override;

  uint64_t GetUsedCount() override;

  uint64_t GetOffset() override;

  uint64_t GetSize() override;

private:
  struct DataDescriptor_32 {
    uint32_t _used;
    uint32_t _offset;
    uint32_t _size : 28;
    uint64_t _priv1 : 4;
    uint32_t _priv2;
    uint32_t _data;
  };

  struct DataDescriptor_64 {
    uint64_t _used;
    uint64_t _offset;
    uint64_t _size : 60;
    uint64_t _priv1 : 4;
    uint32_t _priv2;
    uint64_t _data;
  };

  DataDescriptor_32 *m_data_32;
  DataDescriptor_64 *m_data_64;
};

class NSArrayMSyntheticFrontEnd_1400 : public NSArrayMSyntheticFrontEnd {
public:
  NSArrayMSyntheticFrontEnd_1400(lldb::ValueObjectSP valobj_sp);

  ~NSArrayMSyntheticFrontEnd_1400() override;

  bool Update() override;

protected:
  lldb::addr_t GetDataAddress() override;

  uint64_t GetUsedCount() override;

  uint64_t GetOffset() override;

  uint64_t GetSize() override;

private:
  struct DataDescriptor_32 {
    uint32_t used;
    uint32_t offset;
    uint32_t size;
    uint32_t list;
  };

  struct DataDescriptor_64 {
    uint64_t used;
    uint64_t offset;
    uint64_t size;
    uint64_t list;
  };

  DataDescriptor_32 *m_data_32;
  DataDescriptor_64 *m_data_64;
};

class NSArrayISyntheticFrontEnd_1300 : public SyntheticChildrenFrontEnd {
public:
  NSArrayISyntheticFrontEnd_1300(lldb::ValueObjectSP valobj_sp);

  ~NSArrayISyntheticFrontEnd_1300() override = default;

  size_t CalculateNumChildren() override;

  lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;

  bool Update() override;

  bool MightHaveChildren() override;

  size_t GetIndexOfChildWithName(const ConstString &name) override;

private:
  ExecutionContextRef m_exe_ctx_ref;
  uint8_t m_ptr_size;
  uint64_t m_items;
  lldb::addr_t m_data_ptr;
  CompilerType m_id_type;
};

class NSArrayISyntheticFrontEnd_1400 : public SyntheticChildrenFrontEnd {
public:
  NSArrayISyntheticFrontEnd_1400(lldb::ValueObjectSP valobj_sp);

  ~NSArrayISyntheticFrontEnd_1400() override;

  size_t CalculateNumChildren() override;

  lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;

  bool Update() override;

  bool MightHaveChildren() override;

  size_t GetIndexOfChildWithName(const ConstString &name) override;

private:
  ExecutionContextRef m_exe_ctx_ref;
  uint8_t m_ptr_size;

  struct DataDescriptor_32 {
    uint32_t used;
    uint32_t offset;
    uint32_t size;
    uint32_t list;
  };

  struct DataDescriptor_64 {
    uint64_t used;
    uint64_t offset;
    uint64_t size;
    uint64_t list;
  };

  DataDescriptor_32 *m_data_32;
  DataDescriptor_64 *m_data_64;
  CompilerType m_id_type;
};

class NSArray0SyntheticFrontEnd : public SyntheticChildrenFrontEnd {
public:
  NSArray0SyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);

  ~NSArray0SyntheticFrontEnd() override = default;

  size_t CalculateNumChildren() override;

  lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;

  bool Update() override;

  bool MightHaveChildren() override;

  size_t GetIndexOfChildWithName(const ConstString &name) override;
};

class NSArray1SyntheticFrontEnd : public SyntheticChildrenFrontEnd {
public:
  NSArray1SyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);

  ~NSArray1SyntheticFrontEnd() override = default;

  size_t CalculateNumChildren() override;

  lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;

  bool Update() override;

  bool MightHaveChildren() override;

  size_t GetIndexOfChildWithName(const ConstString &name) override;
};
} // namespace formatters
} // namespace lldb_private

bool lldb_private::formatters::NSArraySummaryProvider(
    ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
  static ConstString g_TypeHint("NSArray");

  ProcessSP process_sp = valobj.GetProcessSP();
  if (!process_sp)
    return false;

  ObjCLanguageRuntime *runtime =
      (ObjCLanguageRuntime *)process_sp->GetLanguageRuntime(
          lldb::eLanguageTypeObjC);

  if (!runtime)
    return false;

  ObjCLanguageRuntime::ClassDescriptorSP descriptor(
      runtime->GetClassDescriptor(valobj));

  if (!descriptor || !descriptor->IsValid())
    return false;

  uint32_t ptr_size = process_sp->GetAddressByteSize();

  lldb::addr_t valobj_addr = valobj.GetValueAsUnsigned(0);

  if (!valobj_addr)
    return false;

  uint64_t value = 0;

  ConstString class_name(descriptor->GetClassName());

  static const ConstString g_NSArrayI("__NSArrayI");
  static const ConstString g_NSArrayM("__NSArrayM");
  static const ConstString g_NSArray0("__NSArray0");
  static const ConstString g_NSArray1("__NSSingleObjectArrayI");
  static const ConstString g_NSArrayCF("__NSCFArray");
  static const ConstString g_NSArrayMLegacy("__NSArrayM_Legacy");
  static const ConstString g_NSArrayMImmutable("__NSArrayM_Immutable");

  if (class_name.IsEmpty())
    return false;

  if (class_name == g_NSArrayI) {
    Status error;
    value = process_sp->ReadUnsignedIntegerFromMemory(valobj_addr + ptr_size,
                                                      ptr_size, 0, error);
    if (error.Fail())
      return false;
  } else if (class_name == g_NSArrayM) {
    Status error;
    value = process_sp->ReadUnsignedIntegerFromMemory(valobj_addr + ptr_size,
                                                      ptr_size, 0, error);
    if (error.Fail())
      return false;
  } else if (class_name == g_NSArrayMLegacy) {
    Status error;
    value = process_sp->ReadUnsignedIntegerFromMemory(valobj_addr + ptr_size,
                                                      ptr_size, 0, error);
    if (error.Fail())
      return false;
  } else if (class_name == g_NSArrayMImmutable) {
    Status error;
    value = process_sp->ReadUnsignedIntegerFromMemory(valobj_addr + ptr_size,
                                                      ptr_size, 0, error);
    if (error.Fail())
      return false;
  } else if (class_name == g_NSArray0) {
    value = 0;
  } else if (class_name == g_NSArray1) {
    value = 1;
  } else if (class_name == g_NSArrayCF) {
    Status error;
    value = process_sp->ReadUnsignedIntegerFromMemory(
        valobj_addr + 2 * ptr_size, ptr_size, 0, error);
    if (error.Fail())
      return false;
  } else {
    auto &map(NSArray_Additionals::GetAdditionalSummaries());
    auto iter = map.find(class_name), end = map.end();
    if (iter != end)
      return iter->second(valobj, stream, options);
    else
      return false;
  }

  std::string prefix, suffix;
  if (Language *language = Language::FindPlugin(options.GetLanguage())) {
    if (!language->GetFormatterPrefixSuffix(valobj, g_TypeHint, prefix,
                                            suffix)) {
      prefix.clear();
      suffix.clear();
    }
  }

  stream.Printf("%s%" PRIu64 " %s%s%s", prefix.c_str(), value, "element",
                value == 1 ? "" : "s", suffix.c_str());
  return true;
}

lldb_private::formatters::NSArrayMSyntheticFrontEnd::NSArrayMSyntheticFrontEnd(
    lldb::ValueObjectSP valobj_sp)
    : SyntheticChildrenFrontEnd(*valobj_sp), m_exe_ctx_ref(), m_ptr_size(8),
      m_id_type() {
  if (valobj_sp) {
    clang::ASTContext *ast = valobj_sp->GetExecutionContextRef()
                                 .GetTargetSP()
                                 ->GetScratchClangASTContext()
                                 ->getASTContext();
    if (ast)
      m_id_type = CompilerType(ast, ast->ObjCBuiltinIdTy);
    if (valobj_sp->GetProcessSP())
      m_ptr_size = valobj_sp->GetProcessSP()->GetAddressByteSize();
  }
}

lldb_private::formatters::NSArrayMSyntheticFrontEnd_109::
    NSArrayMSyntheticFrontEnd_109(lldb::ValueObjectSP valobj_sp)
    : NSArrayMSyntheticFrontEnd(valobj_sp), m_data_32(nullptr),
      m_data_64(nullptr) {}

lldb_private::formatters::NSArrayMSyntheticFrontEnd_1010::
    NSArrayMSyntheticFrontEnd_1010(lldb::ValueObjectSP valobj_sp)
    : NSArrayMSyntheticFrontEnd(valobj_sp), m_data_32(nullptr),
      m_data_64(nullptr) {}

lldb_private::formatters::NSArrayMSyntheticFrontEnd_1400::
    NSArrayMSyntheticFrontEnd_1400(lldb::ValueObjectSP valobj_sp)
    : NSArrayMSyntheticFrontEnd(valobj_sp), m_data_32(nullptr),
      m_data_64(nullptr) {}

size_t
lldb_private::formatters::NSArrayMSyntheticFrontEnd::CalculateNumChildren() {
  return GetUsedCount();
}

lldb::ValueObjectSP
lldb_private::formatters::NSArrayMSyntheticFrontEnd::GetChildAtIndex(
    size_t idx) {
  if (idx >= CalculateNumChildren())
    return lldb::ValueObjectSP();
  lldb::addr_t object_at_idx = GetDataAddress();
  size_t pyhs_idx = idx;
  pyhs_idx += GetOffset();
  if (GetSize() <= pyhs_idx)
    pyhs_idx -= GetSize();
  object_at_idx += (pyhs_idx * m_ptr_size);
  StreamString idx_name;
  idx_name.Printf("[%" PRIu64 "]", (uint64_t)idx);
  return CreateValueObjectFromAddress(idx_name.GetString(), object_at_idx,
                                      m_exe_ctx_ref, m_id_type);
}

bool lldb_private::formatters::NSArrayMSyntheticFrontEnd_109::Update() {
  ValueObjectSP valobj_sp = m_backend.GetSP();
  m_ptr_size = 0;
  delete m_data_32;
  m_data_32 = nullptr;
  delete m_data_64;
  m_data_64 = nullptr;
  if (!valobj_sp)
    return false;
  m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
  Status error;
  error.Clear();
  lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
  if (!process_sp)
    return false;
  m_ptr_size = process_sp->GetAddressByteSize();
  uint64_t data_location = valobj_sp->GetValueAsUnsigned(0) + m_ptr_size;
  if (m_ptr_size == 4) {
    m_data_32 = new DataDescriptor_32();
    process_sp->ReadMemory(data_location, m_data_32, sizeof(DataDescriptor_32),
                           error);
  } else {
    m_data_64 = new DataDescriptor_64();
    process_sp->ReadMemory(data_location, m_data_64, sizeof(DataDescriptor_64),
                           error);
  }
  if (error.Fail())
    return false;
  return false;
}

bool lldb_private::formatters::NSArrayMSyntheticFrontEnd_1010::Update() {
  ValueObjectSP valobj_sp = m_backend.GetSP();
  m_ptr_size = 0;
  delete m_data_32;
  m_data_32 = nullptr;
  delete m_data_64;
  m_data_64 = nullptr;
  if (!valobj_sp)
    return false;
  m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
  Status error;
  error.Clear();
  lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
  if (!process_sp)
    return false;
  m_ptr_size = process_sp->GetAddressByteSize();
  uint64_t data_location = valobj_sp->GetValueAsUnsigned(0) + m_ptr_size;
  if (m_ptr_size == 4) {
    m_data_32 = new DataDescriptor_32();
    process_sp->ReadMemory(data_location, m_data_32, sizeof(DataDescriptor_32),
                           error);
  } else {
    m_data_64 = new DataDescriptor_64();
    process_sp->ReadMemory(data_location, m_data_64, sizeof(DataDescriptor_64),
                           error);
  }
  if (error.Fail())
    return false;
  return false;
}

bool lldb_private::formatters::NSArrayMSyntheticFrontEnd_1400::Update() {
  ValueObjectSP valobj_sp = m_backend.GetSP();
  m_ptr_size = 0;
  delete m_data_32;
  m_data_32 = nullptr;
  delete m_data_64;
  m_data_64 = nullptr;
  if (!valobj_sp)
    return false;
  m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
  Status error;
  error.Clear();
  lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
  if (!process_sp)
    return false;
  m_ptr_size = process_sp->GetAddressByteSize();
  uint64_t data_location = valobj_sp->GetValueAsUnsigned(0) + m_ptr_size;
  if (m_ptr_size == 4) {
    m_data_32 = new DataDescriptor_32();
    process_sp->ReadMemory(data_location, m_data_32, sizeof(DataDescriptor_32),
                           error);
  } else {
    m_data_64 = new DataDescriptor_64();
    process_sp->ReadMemory(data_location, m_data_64, sizeof(DataDescriptor_64),
                           error);
  }
  if (error.Fail())
    return false;
  return false;
}

bool lldb_private::formatters::NSArrayMSyntheticFrontEnd::MightHaveChildren() {
  return true;
}

size_t
lldb_private::formatters::NSArrayMSyntheticFrontEnd::GetIndexOfChildWithName(
    const ConstString &name) {
  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::NSArrayMSyntheticFrontEnd_109::
    ~NSArrayMSyntheticFrontEnd_109() {
  delete m_data_32;
  m_data_32 = nullptr;
  delete m_data_64;
  m_data_64 = nullptr;
}

lldb::addr_t
lldb_private::formatters::NSArrayMSyntheticFrontEnd_109::GetDataAddress() {
  if (!m_data_32 && !m_data_64)
    return LLDB_INVALID_ADDRESS;
  return m_data_32 ? m_data_32->_data : m_data_64->_data;
}

uint64_t
lldb_private::formatters::NSArrayMSyntheticFrontEnd_109::GetUsedCount() {
  if (!m_data_32 && !m_data_64)
    return 0;
  return m_data_32 ? m_data_32->_used : m_data_64->_used;
}

uint64_t lldb_private::formatters::NSArrayMSyntheticFrontEnd_109::GetOffset() {
  if (!m_data_32 && !m_data_64)
    return 0;
  return m_data_32 ? m_data_32->_offset : m_data_64->_offset;
}

uint64_t lldb_private::formatters::NSArrayMSyntheticFrontEnd_109::GetSize() {
  if (!m_data_32 && !m_data_64)
    return 0;
  return m_data_32 ? m_data_32->_size : m_data_64->_size;
}

lldb_private::formatters::NSArrayMSyntheticFrontEnd_1010::
    ~NSArrayMSyntheticFrontEnd_1010() {
  delete m_data_32;
  m_data_32 = nullptr;
  delete m_data_64;
  m_data_64 = nullptr;
}

lldb::addr_t
lldb_private::formatters::NSArrayMSyntheticFrontEnd_1010::GetDataAddress() {
  if (!m_data_32 && !m_data_64)
    return LLDB_INVALID_ADDRESS;
  return m_data_32 ? m_data_32->_data : m_data_64->_data;
}

uint64_t
lldb_private::formatters::NSArrayMSyntheticFrontEnd_1010::GetUsedCount() {
  if (!m_data_32 && !m_data_64)
    return 0;
  return m_data_32 ? m_data_32->_used : m_data_64->_used;
}

uint64_t lldb_private::formatters::NSArrayMSyntheticFrontEnd_1010::GetOffset() {
  if (!m_data_32 && !m_data_64)
    return 0;
  return m_data_32 ? m_data_32->_offset : m_data_64->_offset;
}

uint64_t lldb_private::formatters::NSArrayMSyntheticFrontEnd_1010::GetSize() {
  if (!m_data_32 && !m_data_64)
    return 0;
  return m_data_32 ? m_data_32->_size : m_data_64->_size;
}

lldb_private::formatters::NSArrayMSyntheticFrontEnd_1400::
    ~NSArrayMSyntheticFrontEnd_1400() {
  delete m_data_32;
  m_data_32 = nullptr;
  delete m_data_64;
  m_data_64 = nullptr;
}

lldb::addr_t
lldb_private::formatters::NSArrayMSyntheticFrontEnd_1400::GetDataAddress() {
  if (!m_data_32 && !m_data_64)
    return LLDB_INVALID_ADDRESS;
  return m_data_32 ? m_data_32->list : m_data_64->list;
}

uint64_t
lldb_private::formatters::NSArrayMSyntheticFrontEnd_1400::GetUsedCount() {
  if (!m_data_32 && !m_data_64)
    return 0;
  return m_data_32 ? m_data_32->used : m_data_64->used;
}

uint64_t lldb_private::formatters::NSArrayMSyntheticFrontEnd_1400::GetOffset() {
  if (!m_data_32 && !m_data_64)
    return 0;
  return m_data_32 ? m_data_32->offset : m_data_64->offset;
}

uint64_t lldb_private::formatters::NSArrayMSyntheticFrontEnd_1400::GetSize() {
  if (!m_data_32 && !m_data_64)
    return 0;
  return m_data_32 ? m_data_32->size : m_data_64->size;
}


lldb_private::formatters::NSArrayISyntheticFrontEnd_1300::NSArrayISyntheticFrontEnd_1300(
    lldb::ValueObjectSP valobj_sp)
    : SyntheticChildrenFrontEnd(*valobj_sp), m_exe_ctx_ref(), m_ptr_size(8),
      m_items(0), m_data_ptr(0) {
  if (valobj_sp) {
    CompilerType type = valobj_sp->GetCompilerType();
    if (type) {
      ClangASTContext *ast = valobj_sp->GetExecutionContextRef()
                                 .GetTargetSP()
                                 ->GetScratchClangASTContext();
      if (ast)
        m_id_type = CompilerType(ast->getASTContext(),
                                 ast->getASTContext()->ObjCBuiltinIdTy);
    }
  }
}

size_t
lldb_private::formatters::NSArrayISyntheticFrontEnd_1300::GetIndexOfChildWithName(
    const ConstString &name) {
  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::NSArrayISyntheticFrontEnd_1300::CalculateNumChildren() {
  return m_items;
}

bool lldb_private::formatters::NSArrayISyntheticFrontEnd_1300::Update() {
  m_ptr_size = 0;
  m_items = 0;
  m_data_ptr = 0;
  ValueObjectSP valobj_sp = m_backend.GetSP();
  if (!valobj_sp)
    return false;
  m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
  Status error;
  error.Clear();
  lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
  if (!process_sp)
    return false;
  m_ptr_size = process_sp->GetAddressByteSize();
  uint64_t data_location = valobj_sp->GetValueAsUnsigned(0) + m_ptr_size;
  m_items = process_sp->ReadPointerFromMemory(data_location, error);
  if (error.Fail())
    return false;
  m_data_ptr = data_location + m_ptr_size;
  return false;
}

bool lldb_private::formatters::NSArrayISyntheticFrontEnd_1300::MightHaveChildren() {
  return true;
}

lldb::ValueObjectSP
lldb_private::formatters::NSArrayISyntheticFrontEnd_1300::GetChildAtIndex(
    size_t idx) {
  if (idx >= CalculateNumChildren())
    return lldb::ValueObjectSP();
  lldb::addr_t object_at_idx = m_data_ptr;
  object_at_idx += (idx * m_ptr_size);
  ProcessSP process_sp = m_exe_ctx_ref.GetProcessSP();
  if (!process_sp)
    return lldb::ValueObjectSP();
  Status error;
  if (error.Fail())
    return lldb::ValueObjectSP();
  StreamString idx_name;
  idx_name.Printf("[%" PRIu64 "]", (uint64_t)idx);
  return CreateValueObjectFromAddress(idx_name.GetString(), object_at_idx,
                                      m_exe_ctx_ref, m_id_type);
}

lldb_private::formatters::NSArrayISyntheticFrontEnd_1400::NSArrayISyntheticFrontEnd_1400(
    lldb::ValueObjectSP valobj_sp)
    : SyntheticChildrenFrontEnd(*valobj_sp), m_exe_ctx_ref(), m_ptr_size(8),
      m_data_32(nullptr), m_data_64(nullptr) {
  if (valobj_sp) {
    CompilerType type = valobj_sp->GetCompilerType();
    if (type) {
      ClangASTContext *ast = valobj_sp->GetExecutionContextRef()
                                 .GetTargetSP()
                                 ->GetScratchClangASTContext();
      if (ast)
        m_id_type = CompilerType(ast->getASTContext(),
                                 ast->getASTContext()->ObjCBuiltinIdTy);
    }
  }
}

lldb_private::formatters::NSArrayISyntheticFrontEnd_1400::~NSArrayISyntheticFrontEnd_1400() {
  delete m_data_32;
  m_data_32 = nullptr;
  delete m_data_64;
  m_data_64 = nullptr;
}

size_t
lldb_private::formatters::NSArrayISyntheticFrontEnd_1400::GetIndexOfChildWithName(
    const ConstString &name) {
  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::NSArrayISyntheticFrontEnd_1400::CalculateNumChildren() {
  return m_data_32 ? m_data_32->used : m_data_64->used;
}

bool lldb_private::formatters::NSArrayISyntheticFrontEnd_1400::Update() {
  ValueObjectSP valobj_sp = m_backend.GetSP();
  m_ptr_size = 0;
  delete m_data_32;
  m_data_32 = nullptr;
  delete m_data_64;
  m_data_64 = nullptr;
  if (!valobj_sp)
    return false;
  m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
  Status error;
  error.Clear();
  lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
  if (!process_sp)
    return false;
  m_ptr_size = process_sp->GetAddressByteSize();
  uint64_t data_location = valobj_sp->GetValueAsUnsigned(0) + m_ptr_size;
  if (m_ptr_size == 4) {
    m_data_32 = new DataDescriptor_32();
    process_sp->ReadMemory(data_location, m_data_32, sizeof(DataDescriptor_32),
                           error);
  } else {
    m_data_64 = new DataDescriptor_64();
    process_sp->ReadMemory(data_location, m_data_64, sizeof(DataDescriptor_64),
                           error);
  }
  if (error.Fail())
    return false;
  return false;
}

bool lldb_private::formatters::NSArrayISyntheticFrontEnd_1400::MightHaveChildren() {
  return true;
}

lldb::ValueObjectSP
lldb_private::formatters::NSArrayISyntheticFrontEnd_1400::GetChildAtIndex(
    size_t idx) {
  if (idx >= CalculateNumChildren())
    return lldb::ValueObjectSP();
  lldb::addr_t object_at_idx = m_data_32 ? m_data_32->list : m_data_64->list;
  object_at_idx += (idx * m_ptr_size);
  ProcessSP process_sp = m_exe_ctx_ref.GetProcessSP();
  if (!process_sp)
    return lldb::ValueObjectSP();
  Status error;
  if (error.Fail())
    return lldb::ValueObjectSP();
  StreamString idx_name;
  idx_name.Printf("[%" PRIu64 "]", (uint64_t)idx);
  return CreateValueObjectFromAddress(idx_name.GetString(), object_at_idx,
                                      m_exe_ctx_ref, m_id_type);
}

lldb_private::formatters::NSArray0SyntheticFrontEnd::NSArray0SyntheticFrontEnd(
    lldb::ValueObjectSP valobj_sp)
    : SyntheticChildrenFrontEnd(*valobj_sp) {}

size_t
lldb_private::formatters::NSArray0SyntheticFrontEnd::GetIndexOfChildWithName(
    const ConstString &name) {
  return UINT32_MAX;
}

size_t
lldb_private::formatters::NSArray0SyntheticFrontEnd::CalculateNumChildren() {
  return 0;
}

bool lldb_private::formatters::NSArray0SyntheticFrontEnd::Update() {
  return false;
}

bool lldb_private::formatters::NSArray0SyntheticFrontEnd::MightHaveChildren() {
  return false;
}

lldb::ValueObjectSP
lldb_private::formatters::NSArray0SyntheticFrontEnd::GetChildAtIndex(
    size_t idx) {
  return lldb::ValueObjectSP();
}

lldb_private::formatters::NSArray1SyntheticFrontEnd::NSArray1SyntheticFrontEnd(
    lldb::ValueObjectSP valobj_sp)
    : SyntheticChildrenFrontEnd(*valobj_sp.get()) {}

size_t
lldb_private::formatters::NSArray1SyntheticFrontEnd::GetIndexOfChildWithName(
    const ConstString &name) {
  static const ConstString g_zero("[0]");

  if (name == g_zero)
    return 0;

  return UINT32_MAX;
}

size_t
lldb_private::formatters::NSArray1SyntheticFrontEnd::CalculateNumChildren() {
  return 1;
}

bool lldb_private::formatters::NSArray1SyntheticFrontEnd::Update() {
  return false;
}

bool lldb_private::formatters::NSArray1SyntheticFrontEnd::MightHaveChildren() {
  return true;
}

lldb::ValueObjectSP
lldb_private::formatters::NSArray1SyntheticFrontEnd::GetChildAtIndex(
    size_t idx) {
  static const ConstString g_zero("[0]");

  if (idx == 0) {
    CompilerType id_type(
        m_backend.GetTargetSP()->GetScratchClangASTContext()->GetBasicType(
            lldb::eBasicTypeObjCID));
    return m_backend.GetSyntheticChildAtOffset(
        m_backend.GetProcessSP()->GetAddressByteSize(), id_type, true, g_zero);
  }
  return lldb::ValueObjectSP();
}

SyntheticChildrenFrontEnd *
lldb_private::formatters::NSArraySyntheticFrontEndCreator(
    CXXSyntheticChildren *synth, lldb::ValueObjectSP valobj_sp) {
  if (!valobj_sp)
    return nullptr;

  lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
  if (!process_sp)
    return nullptr;
  AppleObjCRuntime *runtime = llvm::dyn_cast_or_null<AppleObjCRuntime>(
      process_sp->GetObjCLanguageRuntime());
  if (!runtime)
    return nullptr;

  CompilerType valobj_type(valobj_sp->GetCompilerType());
  Flags flags(valobj_type.GetTypeInfo());

  if (flags.IsClear(eTypeIsPointer)) {
    Status error;
    valobj_sp = valobj_sp->AddressOf(error);
    if (error.Fail() || !valobj_sp)
      return nullptr;
  }

  ObjCLanguageRuntime::ClassDescriptorSP descriptor(
      runtime->GetClassDescriptor(*valobj_sp));

  if (!descriptor || !descriptor->IsValid())
    return nullptr;

  ConstString class_name(descriptor->GetClassName());

  static const ConstString g_NSArrayI("__NSArrayI");
  static const ConstString g_NSArrayM("__NSArrayM");
  static const ConstString g_NSArray0("__NSArray0");
  static const ConstString g_NSArray1("__NSSingleObjectArrayI");
  static const ConstString g_NSArrayMLegacy("__NSArrayM_Legacy");
  static const ConstString g_NSArrayMImmutable("__NSArrayM_Immutable");

  if (class_name.IsEmpty())
    return nullptr;

  if (class_name == g_NSArrayI) {
      if (runtime->GetFoundationVersion() >= 1400)
        return (new NSArrayISyntheticFrontEnd_1400(valobj_sp));
      else
        return (new NSArrayISyntheticFrontEnd_1300(valobj_sp));
  } else if (class_name == g_NSArray0) {
    return (new NSArray0SyntheticFrontEnd(valobj_sp));
  } else if (class_name == g_NSArray1) {
    return (new NSArray1SyntheticFrontEnd(valobj_sp));
  } else if (class_name == g_NSArrayM) {
    if (runtime->GetFoundationVersion() >= 1400)
      return (new NSArrayMSyntheticFrontEnd_1400(valobj_sp));
    if (runtime->GetFoundationVersion() >= 1100)
      return (new NSArrayMSyntheticFrontEnd_1010(valobj_sp));
    else
      return (new NSArrayMSyntheticFrontEnd_109(valobj_sp));
  } else {
    auto &map(NSArray_Additionals::GetAdditionalSynthetics());
    auto iter = map.find(class_name), end = map.end();
    if (iter != end)
      return iter->second(synth, valobj_sp);
  }

  return nullptr;
}