PdbUtil.cpp

//===-- PdbUtil.cpp -------------------------------------------------------===//
//
// 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 "PdbUtil.h"

#include "DWARFLocationExpression.h"
#include "PdbIndex.h"
#include "PdbSymUid.h"

#include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
#include "llvm/DebugInfo/CodeView/SymbolDeserializer.h"
#include "llvm/DebugInfo/CodeView/TypeDeserializer.h"
#include "llvm/DebugInfo/PDB/Native/DbiStream.h"
#include "llvm/DebugInfo/PDB/Native/TpiStream.h"

#include "Plugins/Language/CPlusPlus/MSVCUndecoratedNameParser.h"
#include "Plugins/SymbolFile/NativePDB/CodeViewRegisterMapping.h"
#include "lldb/Symbol/Block.h"
#include "lldb/Utility/LLDBAssert.h"
#include "lldb/Utility/LLDBLog.h"
#include "lldb/lldb-enumerations.h"

using namespace lldb_private;
using namespace lldb_private::npdb;
using namespace llvm::codeview;
using namespace llvm::pdb;

// The returned range list is guaranteed to be sorted and no overlaps between
// adjacent ranges because fields in LocalVariableAddrGap are unsigned integers.
static Variable::RangeList
MakeRangeList(const PdbIndex &index, const LocalVariableAddrRange &range,
              llvm::ArrayRef<LocalVariableAddrGap> gaps) {
  lldb::addr_t start =
      index.MakeVirtualAddress(range.ISectStart, range.OffsetStart);
  if (start == LLDB_INVALID_ADDRESS)
    return {};
  lldb::addr_t end = start + range.Range;

  Variable::RangeList result;
  while (!gaps.empty()) {
    const LocalVariableAddrGap &gap = gaps.front();
    lldb::addr_t gap_start = start + gap.GapStartOffset;
    result.Append(start, gap_start - start);
    start = gap_start + gap.Range;
    gaps = gaps.drop_front();
  }

  result.Append(start, end - start);
  return result;
}

namespace {
struct MemberLocations {
  std::map<uint64_t, MemberValLocation> offset_to_location;
  DWARFExpression expr;
  bool is_dwarf = false;

  MemberLocations() = default;
  MemberLocations(const DWARFExpression &expr) : expr(expr), is_dwarf(true) {}
  MemberLocations(uint64_t offset, const MemberValLocation &member_loc) {
    insert(offset, member_loc);
  }

  void insert(uint64_t offset, const MemberValLocation &member_loc) {
    offset_to_location[offset] = member_loc;
  }

  struct Comparator {
  public:
    bool operator()(const MemberLocations &, const MemberLocations &) const {
      return false;
    }
  };
};

// A range map with address ranges to a map of pair of offset and locaitons.
typedef RangeDataVector<lldb::addr_t, lldb::addr_t, MemberLocations, 0,
                        MemberLocations::Comparator>
    RangeMap;

void AddMemberLocationRanges(RangeMap &location_map, uint64_t offset,
                             MemberValLocation member_loc,
                             const Variable::RangeList &ranges) {
  RangeMap new_location_map;
  auto add_overlap_region = [&](lldb::addr_t base, lldb::addr_t end,
                                RangeMap::Entry *entry) {
    RangeMap::Entry overlap_region = {base, end - base, entry->data};
    overlap_region.data.insert(offset, member_loc);
    new_location_map.Append(overlap_region);
  };

  for (const auto &range : ranges) {
    lldb::addr_t base = range.GetRangeBase();
    lldb::addr_t end = range.GetRangeEnd();
    uint32_t base_idx = location_map.FindEntryIndexThatContainsOrFollows(base);
    while (auto *entry = location_map.GetMutableEntryAtIndex(base_idx)) {
      if (base >= end || entry->base >= end)
        break;
      if (entry->data.is_dwarf)
        base = entry->GetRangeEnd();
      else {
        lldb::addr_t entry_end = entry->GetRangeEnd();
        if (base > entry->base) {
          if (end < entry_end)
            new_location_map.Append({end, entry_end - end, entry->data});
          add_overlap_region(base, end < entry_end ? end : entry_end, entry);
          entry->SetRangeEnd(base);
        } else if (base < entry->base) {
          new_location_map.Append(
              {base, entry->base - base, {offset, member_loc}});
          if (entry_end == end)
            entry->data.insert(offset, member_loc);
          else {
            add_overlap_region(entry->base, end, entry);
            entry->ShrinkFront(end - entry->base);
          }
        } else {
          if (end < entry_end) {
            new_location_map.Append({end, entry_end, entry->data});
            entry->SetRangeEnd(end);
          }
          entry->data.insert(offset, member_loc);
        }
        base = entry_end;
      }
      ++base_idx;
    }
    if (base >= end)
      continue;
    new_location_map.Append({base, end - base, {offset, member_loc}});
  }
  for (const auto &entry : new_location_map)
    location_map.Append(entry);
  if (!new_location_map.IsEmpty())
    location_map.Sort();
}

void AddDwarfRange(RangeMap &location_map, const DWARFExpression &expr,
                   const Variable::RangeList &ranges) {
  if (!expr.IsValid())
    return;
  RangeMap new_location_map;
  for (const auto &range : ranges) {
    lldb::addr_t base = range.GetRangeBase();
    lldb::addr_t end = range.GetRangeEnd();
    uint32_t base_idx = location_map.FindEntryIndexThatContains(base);
    uint32_t end_idx = location_map.FindEntryIndexThatContains(end - 1);
    // range is within an entry.
    if (base_idx == end_idx && base_idx != UINT32_MAX) {
      auto *entry = location_map.GetMutableEntryAtIndex(base_idx);
      if (base > entry->base) {
        new_location_map.Append({entry->base, base - entry->base, entry->data});
        entry->ShrinkFront(base - entry->base);
      }
      if (end == entry->GetRangeEnd())
        entry->data = expr;
      else {
        entry->ShrinkFront(end - base);
        new_location_map.Append({base, end - base, expr});
      }
      continue;
    }
    base_idx = location_map.FindEntryIndexThatContainsOrFollows(base);
    if (auto *entry = location_map.GetMutableEntryAtIndex(base_idx)) {
      if (entry->Contains(base) && entry->base != base) {
        entry->SetRangeEnd(base);
        ++base_idx;
      }
    }
    end_idx = location_map.FindEntryIndexThatContainsOrFollows(end - 1);
    if (auto *entry = location_map.GetMutableEntryAtIndex(end_idx)) {
      if (entry->Contains(end - 1)) {
        if (entry->GetRangeEnd() == end)
          ++end_idx;
        else
          entry->ShrinkFront(end - entry->base);
      }
    }

    if (end_idx == UINT32_MAX)
      end_idx = location_map.GetSize();
    // Erase existing ranges covered by new range.
    location_map.Erase(base_idx, end_idx);
    new_location_map.Append({base, end - base, expr});
  }

  for (const auto &entry : new_location_map)
    location_map.Append(entry);
  location_map.Sort();
}
} // namespace

CVTagRecord CVTagRecord::create(CVType type) {
  assert(IsTagRecord(type) && "type is not a tag record!");
  switch (type.kind()) {
  case LF_CLASS:
  case LF_STRUCTURE:
  case LF_INTERFACE: {
    ClassRecord cr;
    llvm::cantFail(TypeDeserializer::deserializeAs<ClassRecord>(type, cr));
    return CVTagRecord(std::move(cr));
  }
  case LF_UNION: {
    UnionRecord ur;
    llvm::cantFail(TypeDeserializer::deserializeAs<UnionRecord>(type, ur));
    return CVTagRecord(std::move(ur));
  }
  case LF_ENUM: {
    EnumRecord er;
    llvm::cantFail(TypeDeserializer::deserializeAs<EnumRecord>(type, er));
    return CVTagRecord(std::move(er));
  }
  default:
    llvm_unreachable("Unreachable!");
  }
}

CVTagRecord::CVTagRecord(ClassRecord &&c)
    : cvclass(std::move(c)),
      m_kind(cvclass.Kind == TypeRecordKind::Struct ? Struct : Class) {}
CVTagRecord::CVTagRecord(UnionRecord &&u)
    : cvunion(std::move(u)), m_kind(Union) {}
CVTagRecord::CVTagRecord(EnumRecord &&e) : cvenum(std::move(e)), m_kind(Enum) {}

PDB_SymType lldb_private::npdb::CVSymToPDBSym(SymbolKind kind) {
  switch (kind) {
  case S_COMPILE3:
  case S_OBJNAME:
    return PDB_SymType::CompilandDetails;
  case S_ENVBLOCK:
    return PDB_SymType::CompilandEnv;
  case S_THUNK32:
  case S_TRAMPOLINE:
    return PDB_SymType::Thunk;
  case S_COFFGROUP:
    return PDB_SymType::CoffGroup;
  case S_EXPORT:
    return PDB_SymType::Export;
  case S_LPROC32:
  case S_GPROC32:
  case S_LPROC32_DPC:
    return PDB_SymType::Function;
  case S_PUB32:
    return PDB_SymType::PublicSymbol;
  case S_INLINESITE:
    return PDB_SymType::InlineSite;
  case S_LOCAL:
  case S_BPREL32:
  case S_REGREL32:
  case S_MANCONSTANT:
  case S_CONSTANT:
  case S_LDATA32:
  case S_GDATA32:
  case S_LMANDATA:
  case S_GMANDATA:
  case S_LTHREAD32:
  case S_GTHREAD32:
    return PDB_SymType::Data;
  case S_BLOCK32:
    return PDB_SymType::Block;
  case S_LABEL32:
    return PDB_SymType::Label;
  case S_CALLSITEINFO:
    return PDB_SymType::CallSite;
  case S_HEAPALLOCSITE:
    return PDB_SymType::HeapAllocationSite;
  case S_CALLEES:
    return PDB_SymType::Callee;
  case S_CALLERS:
    return PDB_SymType::Caller;
  default:
    lldbassert(false && "Invalid symbol record kind!");
  }
  return PDB_SymType::None;
}

PDB_SymType lldb_private::npdb::CVTypeToPDBType(TypeLeafKind kind) {
  switch (kind) {
  case LF_ARRAY:
    return PDB_SymType::ArrayType;
  case LF_ARGLIST:
    return PDB_SymType::FunctionSig;
  case LF_BCLASS:
    return PDB_SymType::BaseClass;
  case LF_BINTERFACE:
    return PDB_SymType::BaseInterface;
  case LF_CLASS:
  case LF_STRUCTURE:
  case LF_INTERFACE:
  case LF_UNION:
    return PDB_SymType::UDT;
  case LF_POINTER:
    return PDB_SymType::PointerType;
  case LF_ENUM:
    return PDB_SymType::Enum;
  case LF_PROCEDURE:
    return PDB_SymType::FunctionSig;
  case LF_BITFIELD:
    return PDB_SymType::BuiltinType;
  default:
    lldbassert(false && "Invalid type record kind!");
  }
  return PDB_SymType::None;
}

bool lldb_private::npdb::SymbolHasAddress(const CVSymbol &sym) {
  switch (sym.kind()) {
  case S_GPROC32:
  case S_LPROC32:
  case S_GPROC32_ID:
  case S_LPROC32_ID:
  case S_LPROC32_DPC:
  case S_LPROC32_DPC_ID:
  case S_THUNK32:
  case S_TRAMPOLINE:
  case S_COFFGROUP:
  case S_BLOCK32:
  case S_LABEL32:
  case S_CALLSITEINFO:
  case S_HEAPALLOCSITE:
  case S_LDATA32:
  case S_GDATA32:
  case S_LMANDATA:
  case S_GMANDATA:
  case S_LTHREAD32:
  case S_GTHREAD32:
    return true;
  default:
    return false;
  }
}

bool lldb_private::npdb::SymbolIsCode(const CVSymbol &sym) {
  switch (sym.kind()) {
  case S_GPROC32:
  case S_LPROC32:
  case S_GPROC32_ID:
  case S_LPROC32_ID:
  case S_LPROC32_DPC:
  case S_LPROC32_DPC_ID:
  case S_THUNK32:
  case S_TRAMPOLINE:
  case S_COFFGROUP:
  case S_BLOCK32:
    return true;
  default:
    return false;
  }
}

template <typename RecordT> RecordT createRecord(const CVSymbol &sym) {
  RecordT record(static_cast<SymbolRecordKind>(sym.kind()));
  cantFail(SymbolDeserializer::deserializeAs<RecordT>(sym, record));
  return record;
}

template <typename RecordT>
static SegmentOffset GetSegmentAndOffset(const CVSymbol &sym) {
  RecordT record = createRecord<RecordT>(sym);
  return {record.Segment, record.CodeOffset};
}

template <>
SegmentOffset GetSegmentAndOffset<TrampolineSym>(const CVSymbol &sym) {
  TrampolineSym record = createRecord<TrampolineSym>(sym);
  return {record.ThunkSection, record.ThunkOffset};
}

template <> SegmentOffset GetSegmentAndOffset<Thunk32Sym>(const CVSymbol &sym) {
  Thunk32Sym record = createRecord<Thunk32Sym>(sym);
  return {record.Segment, record.Offset};
}

template <>
SegmentOffset GetSegmentAndOffset<CoffGroupSym>(const CVSymbol &sym) {
  CoffGroupSym record = createRecord<CoffGroupSym>(sym);
  return {record.Segment, record.Offset};
}

template <> SegmentOffset GetSegmentAndOffset<DataSym>(const CVSymbol &sym) {
  DataSym record = createRecord<DataSym>(sym);
  return {record.Segment, record.DataOffset};
}

template <>
SegmentOffset GetSegmentAndOffset<ThreadLocalDataSym>(const CVSymbol &sym) {
  ThreadLocalDataSym record = createRecord<ThreadLocalDataSym>(sym);
  return {record.Segment, record.DataOffset};
}

SegmentOffset lldb_private::npdb::GetSegmentAndOffset(const CVSymbol &sym) {
  switch (sym.kind()) {
  case S_GPROC32:
  case S_LPROC32:
  case S_GPROC32_ID:
  case S_LPROC32_ID:
  case S_LPROC32_DPC:
  case S_LPROC32_DPC_ID:
    return ::GetSegmentAndOffset<ProcSym>(sym);
  case S_THUNK32:
    return ::GetSegmentAndOffset<Thunk32Sym>(sym);
    break;
  case S_TRAMPOLINE:
    return ::GetSegmentAndOffset<TrampolineSym>(sym);
    break;
  case S_COFFGROUP:
    return ::GetSegmentAndOffset<CoffGroupSym>(sym);
    break;
  case S_BLOCK32:
    return ::GetSegmentAndOffset<BlockSym>(sym);
    break;
  case S_LABEL32:
    return ::GetSegmentAndOffset<LabelSym>(sym);
    break;
  case S_CALLSITEINFO:
    return ::GetSegmentAndOffset<CallSiteInfoSym>(sym);
    break;
  case S_HEAPALLOCSITE:
    return ::GetSegmentAndOffset<HeapAllocationSiteSym>(sym);
    break;
  case S_LDATA32:
  case S_GDATA32:
  case S_LMANDATA:
  case S_GMANDATA:
    return ::GetSegmentAndOffset<DataSym>(sym);
    break;
  case S_LTHREAD32:
  case S_GTHREAD32:
    return ::GetSegmentAndOffset<ThreadLocalDataSym>(sym);
    break;
  default:
    lldbassert(false && "Record does not have a segment/offset!");
  }
  return {0, 0};
}

template <typename RecordT>
SegmentOffsetLength GetSegmentOffsetAndLength(const CVSymbol &sym) {
  RecordT record = createRecord<RecordT>(sym);
  return {record.Segment, record.CodeOffset, record.CodeSize};
}

template <>
SegmentOffsetLength
GetSegmentOffsetAndLength<TrampolineSym>(const CVSymbol &sym) {
  TrampolineSym record = createRecord<TrampolineSym>(sym);
  return {record.ThunkSection, record.ThunkOffset, record.Size};
}

template <>
SegmentOffsetLength GetSegmentOffsetAndLength<Thunk32Sym>(const CVSymbol &sym) {
  Thunk32Sym record = createRecord<Thunk32Sym>(sym);
  return SegmentOffsetLength{record.Segment, record.Offset, record.Length};
}

template <>
SegmentOffsetLength
GetSegmentOffsetAndLength<CoffGroupSym>(const CVSymbol &sym) {
  CoffGroupSym record = createRecord<CoffGroupSym>(sym);
  return SegmentOffsetLength{record.Segment, record.Offset, record.Size};
}

SegmentOffsetLength
lldb_private::npdb::GetSegmentOffsetAndLength(const CVSymbol &sym) {
  switch (sym.kind()) {
  case S_GPROC32:
  case S_LPROC32:
  case S_GPROC32_ID:
  case S_LPROC32_ID:
  case S_LPROC32_DPC:
  case S_LPROC32_DPC_ID:
    return ::GetSegmentOffsetAndLength<ProcSym>(sym);
  case S_THUNK32:
    return ::GetSegmentOffsetAndLength<Thunk32Sym>(sym);
    break;
  case S_TRAMPOLINE:
    return ::GetSegmentOffsetAndLength<TrampolineSym>(sym);
    break;
  case S_COFFGROUP:
    return ::GetSegmentOffsetAndLength<CoffGroupSym>(sym);
    break;
  case S_BLOCK32:
    return ::GetSegmentOffsetAndLength<BlockSym>(sym);
    break;
  default:
    lldbassert(false && "Record does not have a segment/offset/length triple!");
  }
  return {0, 0, 0};
}

bool lldb_private::npdb::IsForwardRefUdt(CVType cvt) {
  ClassRecord cr;
  UnionRecord ur;
  EnumRecord er;
  switch (cvt.kind()) {
  case LF_CLASS:
  case LF_STRUCTURE:
  case LF_INTERFACE:
    llvm::cantFail(TypeDeserializer::deserializeAs<ClassRecord>(cvt, cr));
    return cr.isForwardRef();
  case LF_UNION:
    llvm::cantFail(TypeDeserializer::deserializeAs<UnionRecord>(cvt, ur));
    return ur.isForwardRef();
  case LF_ENUM:
    llvm::cantFail(TypeDeserializer::deserializeAs<EnumRecord>(cvt, er));
    return er.isForwardRef();
  default:
    return false;
  }
}

bool lldb_private::npdb::IsTagRecord(llvm::codeview::CVType cvt) {
  switch (cvt.kind()) {
  case LF_CLASS:
  case LF_STRUCTURE:
  case LF_UNION:
  case LF_ENUM:
    return true;
  default:
    return false;
  }
}

bool lldb_private::npdb::IsClassStructUnion(llvm::codeview::CVType cvt) {
  switch (cvt.kind()) {
  case LF_CLASS:
  case LF_STRUCTURE:
  case LF_UNION:
    return true;
  default:
    return false;
  }
}

bool lldb_private::npdb::IsForwardRefUdt(const PdbTypeSymId &id,
                                         TpiStream &tpi) {
  if (id.is_ipi || id.index.isSimple())
    return false;
  return IsForwardRefUdt(tpi.getType(id.index));
}

bool lldb_private::npdb::IsTagRecord(const PdbTypeSymId &id, TpiStream &tpi) {
  if (id.is_ipi || id.index.isSimple())
    return false;
  return IsTagRecord(tpi.getType(id.index));
}

lldb::AccessType
lldb_private::npdb::TranslateMemberAccess(MemberAccess access) {
  switch (access) {
  case MemberAccess::Private:
    return lldb::eAccessPrivate;
  case MemberAccess::Protected:
    return lldb::eAccessProtected;
  case MemberAccess::Public:
    return lldb::eAccessPublic;
  case MemberAccess::None:
    return lldb::eAccessNone;
  }
  llvm_unreachable("unreachable");
}

TypeIndex lldb_private::npdb::GetFieldListIndex(CVType cvt) {
  switch (cvt.kind()) {
  case LF_CLASS:
  case LF_STRUCTURE:
  case LF_INTERFACE: {
    ClassRecord cr;
    cantFail(TypeDeserializer::deserializeAs<ClassRecord>(cvt, cr));
    return cr.FieldList;
  }
  case LF_UNION: {
    UnionRecord ur;
    cantFail(TypeDeserializer::deserializeAs<UnionRecord>(cvt, ur));
    return ur.FieldList;
  }
  case LF_ENUM: {
    EnumRecord er;
    cantFail(TypeDeserializer::deserializeAs<EnumRecord>(cvt, er));
    return er.FieldList;
  }
  default:
    llvm_unreachable("Unreachable!");
  }
}

TypeIndex lldb_private::npdb::LookThroughModifierRecord(CVType modifier) {
  lldbassert(modifier.kind() == LF_MODIFIER);
  ModifierRecord mr;
  llvm::cantFail(TypeDeserializer::deserializeAs<ModifierRecord>(modifier, mr));
  return mr.ModifiedType;
}

llvm::StringRef lldb_private::npdb::DropNameScope(llvm::StringRef name) {
  return MSVCUndecoratedNameParser::DropScope(name);
}

VariableInfo lldb_private::npdb::GetVariableNameInfo(CVSymbol sym) {
  VariableInfo result = {};

  if (sym.kind() == S_REGREL32) {
    RegRelativeSym reg(SymbolRecordKind::RegRelativeSym);
    cantFail(SymbolDeserializer::deserializeAs<RegRelativeSym>(sym, reg));
    result.type = reg.Type;
    result.name = reg.Name;
    return result;
  }

  if (sym.kind() == S_REGISTER) {
    RegisterSym reg(SymbolRecordKind::RegisterSym);
    cantFail(SymbolDeserializer::deserializeAs<RegisterSym>(sym, reg));
    result.type = reg.Index;
    result.name = reg.Name;
    return result;
  }

  if (sym.kind() == S_LOCAL) {
    LocalSym local(SymbolRecordKind::LocalSym);
    cantFail(SymbolDeserializer::deserializeAs<LocalSym>(sym, local));
    result.type = local.Type;
    result.name = local.Name;
    result.is_param =
        ((local.Flags & LocalSymFlags::IsParameter) != LocalSymFlags::None);
    return result;
  }

  if (sym.kind() == S_GDATA32 || sym.kind() == S_LDATA32) {
    DataSym data(SymbolRecordKind::DataSym);
    cantFail(SymbolDeserializer::deserializeAs<DataSym>(sym, data));
    result.type = data.Type;
    result.name = data.Name;
    return result;
  }

  if (sym.kind() == S_GTHREAD32 || sym.kind() == S_LTHREAD32) {
    ThreadLocalDataSym data(SymbolRecordKind::ThreadLocalDataSym);
    cantFail(SymbolDeserializer::deserializeAs<ThreadLocalDataSym>(sym, data));
    result.type = data.Type;
    result.name = data.Name;
    return result;
  }

  if (sym.kind() == S_CONSTANT) {
    ConstantSym constant(SymbolRecordKind::ConstantSym);
    cantFail(SymbolDeserializer::deserializeAs<ConstantSym>(sym, constant));
    result.type = constant.Type;
    result.name = constant.Name;
    return result;
  }

  lldbassert(false && "Invalid variable record kind!");
  return {};
}

static llvm::FixedStreamArray<FrameData>::Iterator
GetCorrespondingFrameData(lldb::addr_t load_addr,
                          const DebugFrameDataSubsectionRef &fpo_data,
                          const Variable::RangeList &ranges) {
  lldbassert(!ranges.IsEmpty());

  // assume that all variable ranges correspond to one frame data
  using RangeListEntry = Variable::RangeList::Entry;
  const RangeListEntry &range = ranges.GetEntryRef(0);

  auto it = fpo_data.begin();

  // start by searching first frame data range containing variable range
  for (; it != fpo_data.end(); ++it) {
    RangeListEntry fd_range(load_addr + it->RvaStart, it->CodeSize);

    if (fd_range.Contains(range)) {
      break;
    }
  }

  // then first most nested entry that still contains variable range
  auto found = it;
  for (; it != fpo_data.end(); ++it) {
    RangeListEntry fd_range(load_addr + it->RvaStart, it->CodeSize);

    if (!fd_range.Contains(range)) {
      break;
    }
    found = it;
  }

  return found;
}

static bool GetFrameDataProgram(PdbIndex &index,
                                const Variable::RangeList &ranges,
                                llvm::StringRef &out_program) {
  const DebugFrameDataSubsectionRef &new_fpo_data =
      index.dbi().getNewFpoRecords();

  auto frame_data_it =
      GetCorrespondingFrameData(index.GetLoadAddress(), new_fpo_data, ranges);
  if (frame_data_it == new_fpo_data.end())
    return false;

  auto strings = index.pdb().getStringTable();
  if (!strings) {
    consumeError(strings.takeError());
    return false;
  }
  out_program = cantFail(strings->getStringForID(frame_data_it->FrameFunc));
  return true;
}

static RegisterId GetBaseFrameRegister(PdbIndex &index,
                                       PdbCompilandSymId frame_proc_id,
                                       bool is_parameter) {
  CVSymbol frame_proc_cvs = index.ReadSymbolRecord(frame_proc_id);
  if (frame_proc_cvs.kind() != S_FRAMEPROC)
    return RegisterId::NONE;

  FrameProcSym frame_proc(SymbolRecordKind::FrameProcSym);
  cantFail(SymbolDeserializer::deserializeAs<FrameProcSym>(frame_proc_cvs,
                                                           frame_proc));

  CPUType cpu_type = index.compilands()
                         .GetCompiland(frame_proc_id.modi)
                         ->m_compile_opts->Machine;

  return is_parameter ? frame_proc.getParamFramePtrReg(cpu_type)
                      : frame_proc.getLocalFramePtrReg(cpu_type);
}

VariableInfo lldb_private::npdb::GetVariableLocationInfo(
    PdbIndex &index, PdbCompilandSymId var_id, Block &func_block,
    lldb::ModuleSP module) {

  CVSymbol sym = index.ReadSymbolRecord(var_id);

  VariableInfo result = GetVariableNameInfo(sym);

  if (sym.kind() == S_REGREL32) {
    RegRelativeSym reg(SymbolRecordKind::RegRelativeSym);
    cantFail(SymbolDeserializer::deserializeAs<RegRelativeSym>(sym, reg));
    result.location = DWARFExpressionList(
        module, MakeRegRelLocationExpression(reg.Register, reg.Offset, module),
        nullptr);
    return result;
  }

  if (sym.kind() == S_REGISTER) {
    RegisterSym reg(SymbolRecordKind::RegisterSym);
    cantFail(SymbolDeserializer::deserializeAs<RegisterSym>(sym, reg));
    result.location = DWARFExpressionList(
        module, MakeEnregisteredLocationExpression(reg.Register, module),
        nullptr);
    return result;
  }

  if (sym.kind() == S_LOCAL) {
    LocalSym local(SymbolRecordKind::LocalSym);
    if (llvm::Error error =
            SymbolDeserializer::deserializeAs<LocalSym>(sym, local)) {
      llvm::consumeError(std::move(error));
      return result;
    }

    PdbCompilandSymId loc_specifier_id(var_id.modi,
                                       var_id.offset + sym.RecordData.size());
    CVSymbol loc_specifier_cvs;
    // Only used for S_DEFRANGE_FRAMEPOINTER_REL.
    RegisterId base_reg = RegisterId::NONE;
    size_t type_size = GetSizeOfType(result.type, index.tpi());
    // A map from offset of a field in parent to size of the field.
    std::map<uint64_t, size_t> offset_to_size;

    // When overlaps happens, always prefer the one that doesn't split the value
    // into multiple locations and the location parsed first is perfered.
    RangeMap location_map;

    // Iterate through all location records after S_LOCAL. They describe the
    // value of this variable at different locations.
    bool finished = false;
    while (!finished) {
      loc_specifier_cvs = index.ReadSymbolRecord(loc_specifier_id);
      switch (loc_specifier_cvs.kind()) {
      case S_DEFRANGE_FRAMEPOINTER_REL: {
        DefRangeFramePointerRelSym loc(
            SymbolRecordKind::DefRangeFramePointerRelSym);
        if (llvm::Error error =
                SymbolDeserializer::deserializeAs<DefRangeFramePointerRelSym>(
                    loc_specifier_cvs, loc)) {
          llvm::consumeError(std::move(error));
          return result;
        }
        Variable::RangeList raw_ranges =
            MakeRangeList(index, loc.Range, loc.Gaps);
        if (base_reg == RegisterId::NONE) {
          PdbCompilandSymId func_scope_id =
              PdbSymUid(func_block.GetID()).asCompilandSym();
          CVSymbol func_block_cvs = index.ReadSymbolRecord(func_scope_id);
          lldbassert(func_block_cvs.kind() == S_GPROC32 ||
                     func_block_cvs.kind() == S_LPROC32);
          PdbCompilandSymId frame_proc_id(func_scope_id.modi,
                                          func_scope_id.offset +
                                              func_block_cvs.length());
          base_reg =
              GetBaseFrameRegister(index, frame_proc_id, result.is_param);
          if (base_reg == RegisterId::NONE)
            break;
        }
        DWARFExpression expr;
        if (base_reg == RegisterId::VFRAME) {
          llvm::StringRef program;
          if (GetFrameDataProgram(index, raw_ranges, program))
            expr = MakeVFrameRelLocationExpression(program, loc.Hdr.Offset,
                                                   module);
          else {
            // invalid variable
          }
        } else
          expr = MakeRegRelLocationExpression(base_reg, loc.Hdr.Offset, module);
        AddDwarfRange(location_map, expr, raw_ranges);
        break;
      }
      case S_DEFRANGE_REGISTER: {
        DefRangeRegisterSym loc(SymbolRecordKind::DefRangeRegisterSym);
        if (llvm::Error error =
                SymbolDeserializer::deserializeAs<DefRangeRegisterSym>(
                    loc_specifier_cvs, loc)) {
          llvm::consumeError(std::move(error));
          return result;
        }
        RegisterId reg_id = (RegisterId)(uint16_t)loc.Hdr.Register;
        Variable::RangeList raw_ranges =
            MakeRangeList(index, loc.Range, loc.Gaps);
        DWARFExpression expr =
            MakeEnregisteredLocationExpression(reg_id, module);
        AddDwarfRange(location_map, expr, raw_ranges);
        break;
      }
      case S_DEFRANGE_REGISTER_REL: {
        DefRangeRegisterRelSym loc(SymbolRecordKind::DefRangeRegisterRelSym);
        if (llvm::Error error =
                SymbolDeserializer::deserializeAs<DefRangeRegisterRelSym>(
                    loc_specifier_cvs, loc)) {
          llvm::consumeError(std::move(error));
          return result;
        }
        Variable::RangeList raw_ranges =
            MakeRangeList(index, loc.Range, loc.Gaps);
        RegisterId reg_id = (RegisterId)(uint16_t)loc.Hdr.Register;
        DWARFExpression expr;
        if (reg_id == RegisterId::VFRAME) {
          llvm::StringRef program;
          if (GetFrameDataProgram(index, raw_ranges, program))
            expr = MakeVFrameRelLocationExpression(
                program, loc.Hdr.BasePointerOffset, module);
          else {
            // invalid variable
          }
        } else {
          expr = MakeRegRelLocationExpression(reg_id, loc.Hdr.BasePointerOffset,
                                              module);
        }
        // FIXME: If it's UDT, we need to know the size of the value in byte.
        if (!loc.hasSpilledUDTMember())
          AddDwarfRange(location_map, expr, raw_ranges);
        break;
      }
      case S_DEFRANGE_SUBFIELD_REGISTER: {
        DefRangeSubfieldRegisterSym loc(
            SymbolRecordKind::DefRangeSubfieldRegisterSym);
        if (llvm::Error error =
                SymbolDeserializer::deserializeAs<DefRangeSubfieldRegisterSym>(
                    loc_specifier_cvs, loc)) {
          llvm::consumeError(std::move(error));
          return result;
        }

        Variable::RangeList ranges = MakeRangeList(index, loc.Range, loc.Gaps);
        uint32_t reg_size =
            GetRegisterSize((RegisterId)(uint16_t)loc.Hdr.Register);
        if (reg_size == 0)
          break;
        offset_to_size[loc.Hdr.OffsetInParent] = reg_size;
        AddMemberLocationRanges(location_map, loc.Hdr.OffsetInParent,
                                {loc.Hdr.Register, 0, true}, ranges);
        break;
      }
      // FIXME: Handle other kinds. LLVM only generates the 4 types of records
      // above. MSVC generates other location types.
      case S_DEFRANGE:
      case S_DEFRANGE_SUBFIELD:
      case S_DEFRANGE_FRAMEPOINTER_REL_FULL_SCOPE:
        break;
      default:
        finished = true;
        break;
      }
      loc_specifier_id = PdbCompilandSymId(
          loc_specifier_id.modi,
          loc_specifier_id.offset + loc_specifier_cvs.RecordData.size());
    }
    for (const auto &entry : location_map) {
      DWARFExpression dwarf_expr =
          entry.data.is_dwarf ? entry.data.expr
                              : MakeEnregisteredLocationExpressionForComposite(
                                    entry.data.offset_to_location,
                                    offset_to_size, type_size, module);

      result.location.AddExpression(entry.GetRangeBase(), entry.GetRangeEnd(),
                                     dwarf_expr);
    }
    return result;
  }
  llvm_unreachable("Symbol is not a local variable!");
  return result;
}

lldb::BasicType
lldb_private::npdb::GetCompilerTypeForSimpleKind(SimpleTypeKind kind) {
  switch (kind) {
  case SimpleTypeKind::Boolean128:
  case SimpleTypeKind::Boolean16:
  case SimpleTypeKind::Boolean32:
  case SimpleTypeKind::Boolean64:
  case SimpleTypeKind::Boolean8:
    return lldb::eBasicTypeBool;
  case SimpleTypeKind::Byte:
  case SimpleTypeKind::UnsignedCharacter:
    return lldb::eBasicTypeUnsignedChar;
  case SimpleTypeKind::NarrowCharacter:
    return lldb::eBasicTypeChar;
  case SimpleTypeKind::SignedCharacter:
  case SimpleTypeKind::SByte:
    return lldb::eBasicTypeSignedChar;
  case SimpleTypeKind::Character16:
    return lldb::eBasicTypeChar16;
  case SimpleTypeKind::Character32:
    return lldb::eBasicTypeChar32;
  case SimpleTypeKind::Character8:
    return lldb::eBasicTypeChar8;
  case SimpleTypeKind::Complex80:
    return lldb::eBasicTypeLongDoubleComplex;
  case SimpleTypeKind::Complex64:
    return lldb::eBasicTypeDoubleComplex;
  case SimpleTypeKind::Complex32:
    return lldb::eBasicTypeFloatComplex;
  case SimpleTypeKind::Float128:
  case SimpleTypeKind::Float80:
    return lldb::eBasicTypeLongDouble;
  case SimpleTypeKind::Float64:
    return lldb::eBasicTypeDouble;
  case SimpleTypeKind::Float32:
    return lldb::eBasicTypeFloat;
  case SimpleTypeKind::Float16:
    return lldb::eBasicTypeHalf;
  case SimpleTypeKind::Int128:
    return lldb::eBasicTypeInt128;
  case SimpleTypeKind::Int64:
  case SimpleTypeKind::Int64Quad:
    return lldb::eBasicTypeLongLong;
  case SimpleTypeKind::Int32:
    return lldb::eBasicTypeInt;
  case SimpleTypeKind::Int16:
  case SimpleTypeKind::Int16Short:
    return lldb::eBasicTypeShort;
  case SimpleTypeKind::UInt128:
    return lldb::eBasicTypeUnsignedInt128;
  case SimpleTypeKind::UInt64:
  case SimpleTypeKind::UInt64Quad:
    return lldb::eBasicTypeUnsignedLongLong;
  case SimpleTypeKind::HResult:
  case SimpleTypeKind::UInt32:
    return lldb::eBasicTypeUnsignedInt;
  case SimpleTypeKind::UInt16:
  case SimpleTypeKind::UInt16Short:
    return lldb::eBasicTypeUnsignedShort;
  case SimpleTypeKind::Int32Long:
    return lldb::eBasicTypeLong;
  case SimpleTypeKind::UInt32Long:
    return lldb::eBasicTypeUnsignedLong;
  case SimpleTypeKind::Void:
    return lldb::eBasicTypeVoid;
  case SimpleTypeKind::WideCharacter:
    return lldb::eBasicTypeWChar;
  default:
    return lldb::eBasicTypeInvalid;
  }
}

size_t lldb_private::npdb::GetTypeSizeForSimpleKind(SimpleTypeKind kind) {
  switch (kind) {
  case SimpleTypeKind::Boolean128:
  case SimpleTypeKind::Int128:
  case SimpleTypeKind::UInt128:
  case SimpleTypeKind::Float128:
    return 16;
  case SimpleTypeKind::Complex80:
  case SimpleTypeKind::Float80:
    return 10;
  case SimpleTypeKind::Boolean64:
  case SimpleTypeKind::Complex64:
  case SimpleTypeKind::UInt64:
  case SimpleTypeKind::UInt64Quad:
  case SimpleTypeKind::Float64:
  case SimpleTypeKind::Int64:
  case SimpleTypeKind::Int64Quad:
    return 8;
  case SimpleTypeKind::Boolean32:
  case SimpleTypeKind::Character32:
  case SimpleTypeKind::Complex32:
  case SimpleTypeKind::Float32:
  case SimpleTypeKind::Int32:
  case SimpleTypeKind::Int32Long:
  case SimpleTypeKind::UInt32Long:
  case SimpleTypeKind::HResult:
  case SimpleTypeKind::UInt32:
    return 4;
  case SimpleTypeKind::Boolean16:
  case SimpleTypeKind::Character16:
  case SimpleTypeKind::Float16:
  case SimpleTypeKind::Int16:
  case SimpleTypeKind::Int16Short:
  case SimpleTypeKind::UInt16:
  case SimpleTypeKind::UInt16Short:
  case SimpleTypeKind::WideCharacter:
    return 2;
  case SimpleTypeKind::Boolean8:
  case SimpleTypeKind::Byte:
  case SimpleTypeKind::UnsignedCharacter:
  case SimpleTypeKind::NarrowCharacter:
  case SimpleTypeKind::SignedCharacter:
  case SimpleTypeKind::SByte:
  case SimpleTypeKind::Character8:
    return 1;
  case SimpleTypeKind::Void:
  default:
    return 0;
  }
}

PdbTypeSymId lldb_private::npdb::GetBestPossibleDecl(PdbTypeSymId id,
                                                     TpiStream &tpi) {
  if (id.index.isSimple())
    return id;

  CVType cvt = tpi.getType(id.index);

  // Only tag records have a best and a worst record.
  if (!IsTagRecord(cvt))
    return id;

  // Tag records that are not forward decls are full decls, hence they are the
  // best.
  if (!IsForwardRefUdt(cvt))
    return id;

  return llvm::cantFail(tpi.findFullDeclForForwardRef(id.index));
}

template <typename RecordType> static size_t GetSizeOfTypeInternal(CVType cvt) {
  RecordType record;
  llvm::cantFail(TypeDeserializer::deserializeAs<RecordType>(cvt, record));
  return record.getSize();
}

size_t lldb_private::npdb::GetSizeOfType(PdbTypeSymId id,
                                         llvm::pdb::TpiStream &tpi) {
  if (id.index.isSimple()) {
    switch (id.index.getSimpleMode()) {
    case SimpleTypeMode::Direct:
      return GetTypeSizeForSimpleKind(id.index.getSimpleKind());
    case SimpleTypeMode::NearPointer32:
    case SimpleTypeMode::FarPointer32:
      return 4;
    case SimpleTypeMode::NearPointer64:
      return 8;
    case SimpleTypeMode::NearPointer128:
      return 16;
    default:
      break;
    }
    return 0;
  }

  TypeIndex index = id.index;
  if (IsForwardRefUdt(index, tpi))
    index = llvm::cantFail(tpi.findFullDeclForForwardRef(index));

  CVType cvt = tpi.getType(index);
  switch (cvt.kind()) {
  case LF_MODIFIER:
    return GetSizeOfType({LookThroughModifierRecord(cvt)}, tpi);
  case LF_ENUM: {
    EnumRecord record;
    llvm::cantFail(TypeDeserializer::deserializeAs<EnumRecord>(cvt, record));
    return GetSizeOfType({record.UnderlyingType}, tpi);
  }
  case LF_POINTER:
    return GetSizeOfTypeInternal<PointerRecord>(cvt);
  case LF_ARRAY:
    return GetSizeOfTypeInternal<ArrayRecord>(cvt);
  case LF_CLASS:
  case LF_STRUCTURE:
  case LF_INTERFACE:
    return GetSizeOfTypeInternal<ClassRecord>(cvt);
  case LF_UNION:
    return GetSizeOfTypeInternal<UnionRecord>(cvt);
  case LF_BITFIELD: {
    BitFieldRecord record;
    llvm::cantFail(TypeDeserializer::deserializeAs<BitFieldRecord>(cvt, record));
    return GetSizeOfType({record.Type}, tpi);
  }
  default:
    break;
  }
  return 0;
}