lldb/source/Plugins/Language/ObjC/NSException.cpp

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

#include "clang/AST/DeclCXX.h"

#include "Cocoa.h"

#include "lldb/Core/ValueObject.h"
#include "lldb/Core/ValueObjectConstResult.h"
#include "lldb/DataFormatters/FormattersHelpers.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Target/ObjCLanguageRuntime.h"
#include "lldb/Target/ProcessStructReader.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/Language/ObjC/NSString.h"

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

static bool ExtractFields(ValueObject &valobj, ValueObjectSP *name_sp,
                          ValueObjectSP *reason_sp,
                          ValueObjectSP *userinfo_sp) {
  ProcessSP process_sp(valobj.GetProcessSP());
  if (!process_sp)
    return false;

  lldb::addr_t ptr = LLDB_INVALID_ADDRESS;

  CompilerType valobj_type(valobj.GetCompilerType());
  Flags type_flags(valobj_type.GetTypeInfo());
  if (type_flags.AllClear(eTypeHasValue)) {
    if (valobj.IsBaseClass() && valobj.GetParent())
      ptr = valobj.GetParent()->GetValueAsUnsigned(LLDB_INVALID_ADDRESS);
  } else {
    ptr = valobj.GetValueAsUnsigned(LLDB_INVALID_ADDRESS);
  }

  if (ptr == LLDB_INVALID_ADDRESS)
    return false;
  size_t ptr_size = process_sp->GetAddressByteSize();

  Status error;
  auto name = process_sp->ReadPointerFromMemory(ptr + 1 * ptr_size, error);
  if (error.Fail() || name == LLDB_INVALID_ADDRESS)
    return false;
  auto reason = process_sp->ReadPointerFromMemory(ptr + 2 * ptr_size, error);
  if (error.Fail() || reason == LLDB_INVALID_ADDRESS)
    return false;
  auto userinfo = process_sp->ReadPointerFromMemory(ptr + 3 * ptr_size, error);
  if (error.Fail() || userinfo == LLDB_INVALID_ADDRESS)
    return false;

  InferiorSizedWord name_isw(name, *process_sp);
  InferiorSizedWord reason_isw(reason, *process_sp);
  InferiorSizedWord userinfo_isw(userinfo, *process_sp);

  CompilerType voidstar = process_sp->GetTarget()
                              .GetScratchClangASTContext()
                              ->GetBasicType(lldb::eBasicTypeVoid)
                              .GetPointerType();

  if (name_sp)
    *name_sp = ValueObject::CreateValueObjectFromData(
        "name", name_isw.GetAsData(process_sp->GetByteOrder()),
        valobj.GetExecutionContextRef(), voidstar);
  if (reason_sp)
    *reason_sp = ValueObject::CreateValueObjectFromData(
        "reason", reason_isw.GetAsData(process_sp->GetByteOrder()),
        valobj.GetExecutionContextRef(), voidstar);
  if (userinfo_sp)
    *userinfo_sp = ValueObject::CreateValueObjectFromData(
        "userInfo", userinfo_isw.GetAsData(process_sp->GetByteOrder()),
        valobj.GetExecutionContextRef(), voidstar);

  return true;
}

bool lldb_private::formatters::NSException_SummaryProvider(
    ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
  lldb::ValueObjectSP name_sp;
  lldb::ValueObjectSP reason_sp;
  if (!ExtractFields(valobj, &name_sp, &reason_sp, nullptr))
    return false;

  if (!name_sp || !reason_sp)
    return false;

  StreamString name_str_summary;
  StreamString reason_str_summary;
  if (NSStringSummaryProvider(*name_sp, name_str_summary, options) &&
      NSStringSummaryProvider(*reason_sp, reason_str_summary, options) &&
      !name_str_summary.Empty() && !reason_str_summary.Empty()) {
    stream.Printf("name: %s - reason: %s", name_str_summary.GetData(),
                  reason_str_summary.GetData());
    return true;
  } else
    return false;
}

class NSExceptionSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
public:
  NSExceptionSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
      : SyntheticChildrenFrontEnd(*valobj_sp) {}

  ~NSExceptionSyntheticFrontEnd() override = default;

  size_t CalculateNumChildren() override {
    return 1;
  }

  lldb::ValueObjectSP GetChildAtIndex(size_t idx) override {
    switch (idx) {
      case 0: return m_userinfo_sp;
    }
    return lldb::ValueObjectSP();
  }

  bool Update() override {
    m_userinfo_sp.reset();
    if (!ExtractFields(m_backend, nullptr, nullptr, &m_userinfo_sp)) {
      return false;
    }
    return true;
  }

  bool MightHaveChildren() override { return true; }

  size_t GetIndexOfChildWithName(const ConstString &name) override {
    static ConstString g___userInfo("userInfo");
    if (name == g___userInfo)
      return 0;
    return UINT32_MAX;
  }

private:
  ValueObjectSP m_userinfo_sp;
};

SyntheticChildrenFrontEnd *
lldb_private::formatters::NSExceptionSyntheticFrontEndCreator(
    CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
  lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
  if (!process_sp)
    return nullptr;
  ObjCLanguageRuntime *runtime =
      (ObjCLanguageRuntime *)process_sp->GetLanguageRuntime(
          lldb::eLanguageTypeObjC);
  if (!runtime)
    return nullptr;

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

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

  const char *class_name = descriptor->GetClassName().GetCString();

  if (!class_name || !*class_name)
    return nullptr;

  if (!strcmp(class_name, "NSException"))
    return (new NSExceptionSyntheticFrontEnd(valobj_sp));
  else if (!strcmp(class_name, "NSCFException"))
    return (new NSExceptionSyntheticFrontEnd(valobj_sp));
  else if (!strcmp(class_name, "__NSCFException"))
    return (new NSExceptionSyntheticFrontEnd(valobj_sp));

  return nullptr;
}