/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h

Bug Summary

File:	include/llvm/Support/Error.h
Warning:	line 201, column 5 Potential leak of memory pointed to by 'Payload._M_t._M_head_impl'

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name PDB.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-8/lib/clang/8.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/lld/COFF -I /build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF -I /build/llvm-toolchain-snapshot-8~svn345461/tools/lld/include -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/lld/include -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/include -I /build/llvm-toolchain-snapshot-8~svn345461/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/include/clang/8.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-8/lib/clang/8.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/lld/COFF -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-10-27-211344-32123-1 -x c++ /build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp -faddrsig

/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp

→

1//===- PDB.cpp ------------------------------------------------------------===//
2//
3//                             The LLVM Linker
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//

10#include "PDB.h"
11#include "Chunks.h"
12#include "Config.h"
13#include "Driver.h"
14#include "SymbolTable.h"
15#include "Symbols.h"
16#include "Writer.h"
17#include "lld/Common/ErrorHandler.h"
18#include "lld/Common/Timer.h"
19#include "llvm/DebugInfo/CodeView/DebugFrameDataSubsection.h"
20#include "llvm/DebugInfo/CodeView/DebugSubsectionRecord.h"
21#include "llvm/DebugInfo/CodeView/GlobalTypeTableBuilder.h"
22#include "llvm/DebugInfo/CodeView/LazyRandomTypeCollection.h"
23#include "llvm/DebugInfo/CodeView/MergingTypeTableBuilder.h"
24#include "llvm/DebugInfo/CodeView/RecordName.h"
25#include "llvm/DebugInfo/CodeView/SymbolDeserializer.h"
26#include "llvm/DebugInfo/CodeView/SymbolSerializer.h"
27#include "llvm/DebugInfo/CodeView/TypeDeserializer.h"
28#include "llvm/DebugInfo/CodeView/TypeDumpVisitor.h"
29#include "llvm/DebugInfo/CodeView/TypeIndexDiscovery.h"
30#include "llvm/DebugInfo/CodeView/TypeStreamMerger.h"
31#include "llvm/DebugInfo/MSF/MSFBuilder.h"
32#include "llvm/DebugInfo/MSF/MSFCommon.h"
33#include "llvm/DebugInfo/PDB/GenericError.h"
34#include "llvm/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.h"
35#include "llvm/DebugInfo/PDB/Native/DbiStream.h"
36#include "llvm/DebugInfo/PDB/Native/DbiStreamBuilder.h"
37#include "llvm/DebugInfo/PDB/Native/GSIStreamBuilder.h"
38#include "llvm/DebugInfo/PDB/Native/InfoStream.h"
39#include "llvm/DebugInfo/PDB/Native/InfoStreamBuilder.h"
40#include "llvm/DebugInfo/PDB/Native/NativeSession.h"
41#include "llvm/DebugInfo/PDB/Native/PDBFile.h"
42#include "llvm/DebugInfo/PDB/Native/PDBFileBuilder.h"
43#include "llvm/DebugInfo/PDB/Native/PDBStringTableBuilder.h"
44#include "llvm/DebugInfo/PDB/Native/TpiHashing.h"
45#include "llvm/DebugInfo/PDB/Native/TpiStream.h"
46#include "llvm/DebugInfo/PDB/Native/TpiStreamBuilder.h"
47#include "llvm/DebugInfo/PDB/PDB.h"
48#include "llvm/Object/COFF.h"
49#include "llvm/Object/CVDebugRecord.h"
50#include "llvm/Support/BinaryByteStream.h"
51#include "llvm/Support/Endian.h"
52#include "llvm/Support/FormatVariadic.h"
53#include "llvm/Support/JamCRC.h"
54#include "llvm/Support/Path.h"
55#include "llvm/Support/ScopedPrinter.h"
56#include <memory>

58using namespace lld;
59using namespace lld::coff;
60using namespace llvm;
61using namespace llvm::codeview;

63using llvm::object::coff_section;

65static ExitOnError ExitOnErr;

67static Timer TotalPdbLinkTimer("PDB Emission (Cumulative)", Timer::root());

69static Timer AddObjectsTimer("Add Objects", TotalPdbLinkTimer);
70static Timer TypeMergingTimer("Type Merging", AddObjectsTimer);
71static Timer SymbolMergingTimer("Symbol Merging", AddObjectsTimer);
72static Timer GlobalsLayoutTimer("Globals Stream Layout", TotalPdbLinkTimer);
73static Timer TpiStreamLayoutTimer("TPI Stream Layout", TotalPdbLinkTimer);
74static Timer DiskCommitTimer("Commit to Disk", TotalPdbLinkTimer);

76namespace {
77/// Map from type index and item index in a type server PDB to the
78/// corresponding index in the destination PDB.
79struct CVIndexMap {
SmallVector<TypeIndex, 0> TPIMap;
SmallVector<TypeIndex, 0> IPIMap;
bool IsTypeServerMap = false;
83};

85class DebugSHandler;

87class PDBLinker {
friend DebugSHandler;

90public:
PDBLinker(SymbolTable *Symtab)
    : Alloc(), Symtab(Symtab), Builder(Alloc), TypeTable(Alloc),
      IDTable(Alloc), GlobalTypeTable(Alloc), GlobalIDTable(Alloc) {
  // This isn't strictly necessary, but link.exe usually puts an empty string
  // as the first "valid" string in the string table, so we do the same in
  // order to maintain as much byte-for-byte compatibility as possible.
  PDBStrTab.insert("");
}

/// Emit the basic PDB structure: initial streams, headers, etc.
void initialize(llvm::codeview::DebugInfo *BuildId);

/// Add natvis files specified on the command line.
void addNatvisFiles();

/// Link CodeView from each object file in the symbol table into the PDB.
void addObjectsToPDB();

/// Link CodeView from a single object file into the PDB.
void addObjFile(ObjFile *File);

/// Produce a mapping from the type and item indices used in the object
/// file to those in the destination PDB.
///
/// If the object file uses a type server PDB (compiled with /Zi), merge TPI
/// and IPI from the type server PDB and return a map for it. Each unique type
/// server PDB is merged at most once, so this may return an existing index
/// mapping.
///
/// If the object does not use a type server PDB (compiled with /Z7), we merge
/// all the type and item records from the .debug$S stream and fill in the
/// caller-provided ObjectIndexMap.
Expected<const CVIndexMap&> mergeDebugT(ObjFile *File,
                                        CVIndexMap &ObjectIndexMap);

Expected<const CVIndexMap&> maybeMergeTypeServerPDB(ObjFile *File,
                                                    TypeServer2Record &TS);

/// Add the section map and section contributions to the PDB.
void addSections(ArrayRef<OutputSection *> OutputSections,
                 ArrayRef<uint8_t> SectionTable);

/// Write the PDB to disk and store the Guid generated for it in *Guid.
void commit(codeview::GUID *Guid);

136private:
BumpPtrAllocator Alloc;

SymbolTable *Symtab;

pdb::PDBFileBuilder Builder;

/// Type records that will go into the PDB TPI stream.
MergingTypeTableBuilder TypeTable;

/// Item records that will go into the PDB IPI stream.
MergingTypeTableBuilder IDTable;

/// Type records that will go into the PDB TPI stream (for /DEBUG:GHASH)
GlobalTypeTableBuilder GlobalTypeTable;

/// Item records that will go into the PDB IPI stream (for /DEBUG:GHASH)
GlobalTypeTableBuilder GlobalIDTable;

/// PDBs use a single global string table for filenames in the file checksum
/// table.
DebugStringTableSubsection PDBStrTab;

llvm::SmallString<128> NativePath;

/// A list of other PDBs which are loaded during the linking process and which
/// we need to keep around since the linking operation may reference pointers
/// inside of these PDBs.
llvm::SmallVector<std::unique_ptr<pdb::NativeSession>, 2> LoadedPDBs;

std::vector<pdb::SecMapEntry> SectionMap;

/// Type index mappings of type server PDBs that we've loaded so far.
std::map<GUID, CVIndexMap> TypeServerIndexMappings;

/// List of TypeServer PDBs which cannot be loaded.
/// Cached to prevent repeated load attempts.
std::map<GUID, std::string> MissingTypeServerPDBs;
174};

176class DebugSHandler {
PDBLinker &Linker;

/// The object file whose .debug$S sections we're processing.
ObjFile &File;

/// The result of merging type indices.
const CVIndexMap &IndexMap;

/// The DEBUG_S_STRINGTABLE subsection.  These strings are referred to by
/// index from other records in the .debug$S section.  All of these strings
/// need to be added to the global PDB string table, and all references to
/// these strings need to have their indices re-written to refer to the
/// global PDB string table.
DebugStringTableSubsectionRef CVStrTab;

/// The DEBUG_S_FILECHKSMS subsection.  As above, these are referred to
/// by other records in the .debug$S section and need to be merged into the
/// PDB.
DebugChecksumsSubsectionRef Checksums;

/// The DEBUG_S_FRAMEDATA subsection(s).  There can be more than one of
/// these and they need not appear in any specific order.  However, they
/// contain string table references which need to be re-written, so we
/// collect them all here and re-write them after all subsections have been
/// discovered and processed.
std::vector<DebugFrameDataSubsectionRef> NewFpoFrames;

/// Pointers to raw memory that we determine have string table references
/// that need to be re-written.  We first process all .debug$S subsections
/// to ensure that we can handle subsections written in any order, building
/// up this list as we go.  At the end, we use the string table (which must
/// have been discovered by now else it is an error) to re-write these
/// references.
std::vector<ulittle32_t *> StringTableReferences;

212public:
DebugSHandler(PDBLinker &Linker, ObjFile &File, const CVIndexMap &IndexMap)
    : Linker(Linker), File(File), IndexMap(IndexMap) {}

void handleDebugS(lld::coff::SectionChunk &DebugS);
void finish();
218};
219}

221// Visual Studio's debugger requires absolute paths in various places in the
222// PDB to work without additional configuration:
223// https://docs.microsoft.com/en-us/visualstudio/debugger/debug-source-files-common-properties-solution-property-pages-dialog-box
224static void pdbMakeAbsolute(SmallVectorImpl<char> &FileName) {
// The default behavior is to produce paths that are valid within the context
// of the machine that you perform the link on.  If the linker is running on
// a POSIX system, we will output absolute POSIX paths.  If the linker is
// running on a Windows system, we will output absolute Windows paths.  If the
// user desires any other kind of behavior, they should explicitly pass
// /pdbsourcepath, in which case we will treat the exact string the user
// passed in as the gospel and not normalize, canonicalize it.
if (sys::path::is_absolute(FileName, sys::path::Style::windows) ||
    sys::path::is_absolute(FileName, sys::path::Style::posix))
  return;

// It's not absolute in any path syntax.  Relative paths necessarily refer to
// the local file system, so we can make it native without ending up with a
// nonsensical path.
sys::path::native(FileName);
if (Config->PDBSourcePath.empty()) {
  sys::fs::make_absolute(FileName);
  return;
}
// Only apply native and dot removal to the relative file path.  We want to
// leave the path the user specified untouched since we assume they specified
// it for a reason.
sys::path::remove_dots(FileName, /*remove_dot_dots=*/true);

SmallString<128> AbsoluteFileName = Config->PDBSourcePath;
sys::path::append(AbsoluteFileName, FileName);
FileName = std::move(AbsoluteFileName);
252}

254static SectionChunk *findByName(ArrayRef<SectionChunk *> Sections,
                              StringRef Name) {
for (SectionChunk *C : Sections)
  if (C->getSectionName() == Name)
    return C;
return nullptr;
260}

262static ArrayRef<uint8_t> consumeDebugMagic(ArrayRef<uint8_t> Data,
                                         StringRef SecName) {
// First 4 bytes are section magic.
if (Data.size() < 4)
  fatal(SecName + " too short");
if (support::endian::read32le(Data.data()) != COFF::DEBUG_SECTION_MAGIC)
  fatal(SecName + " has an invalid magic");
return Data.slice(4);
270}

272static ArrayRef<uint8_t> getDebugSection(ObjFile *File, StringRef SecName) {
if (SectionChunk *Sec = findByName(File->getDebugChunks(), SecName))
  return consumeDebugMagic(Sec->getContents(), SecName);
return {};
276}

278// A COFF .debug$H section is currently a clang extension.  This function checks
279// if a .debug$H section is in a format that we expect / understand, so that we
280// can ignore any sections which are coincidentally also named .debug$H but do
281// not contain a format we recognize.
282static bool canUseDebugH(ArrayRef<uint8_t> DebugH) {
if (DebugH.size() < sizeof(object::debug_h_header))
  return false;
auto *Header =
    reinterpret_cast<const object::debug_h_header *>(DebugH.data());
DebugH = DebugH.drop_front(sizeof(object::debug_h_header));
return Header->Magic == COFF::DEBUG_HASHES_SECTION_MAGIC &&
       Header->Version == 0 &&
       Header->HashAlgorithm == uint16_t(GlobalTypeHashAlg::SHA1_8) &&
       (DebugH.size() % 8 == 0);
292}

294static Optional<ArrayRef<uint8_t>> getDebugH(ObjFile *File) {
SectionChunk *Sec = findByName(File->getDebugChunks(), ".debug$H");
if (!Sec)
  return llvm::None;
ArrayRef<uint8_t> Contents = Sec->getContents();
if (!canUseDebugH(Contents))
  return None;
return Contents;
302}

304static ArrayRef<GloballyHashedType>
305getHashesFromDebugH(ArrayRef<uint8_t> DebugH) {
assert(canUseDebugH(DebugH))((canUseDebugH(DebugH)) ? static_cast<void> (0) : __assert_fail
 ("canUseDebugH(DebugH)", "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 306, __PRETTY_FUNCTION__));

DebugH = DebugH.drop_front(sizeof(object::debug_h_header));
uint32_t Count = DebugH.size() / sizeof(GloballyHashedType);
return {reinterpret_cast<const GloballyHashedType *>(DebugH.data()), Count};
311}

313static void addTypeInfo(pdb::TpiStreamBuilder &TpiBuilder,
                      TypeCollection &TypeTable) {
// Start the TPI or IPI stream header.
TpiBuilder.setVersionHeader(pdb::PdbTpiV80);

// Flatten the in memory type table and hash each type.
TypeTable.ForEachRecord([&](TypeIndex TI, const CVType &Type) {
  auto Hash = pdb::hashTypeRecord(Type);
  if (auto E = Hash.takeError())
    fatal("type hashing error");
  TpiBuilder.addTypeRecord(Type.RecordData, *Hash);
});
325}

327static Optional<TypeServer2Record>
328maybeReadTypeServerRecord(CVTypeArray &Types) {
auto I = Types.begin();
if (I == Types.end())
  return None;
const CVType &Type = *I;
if (Type.kind() != LF_TYPESERVER2)
  return None;
TypeServer2Record TS;
if (auto EC = TypeDeserializer::deserializeAs(const_cast<CVType &>(Type), TS))
  fatal("error reading type server record: " + toString(std::move(EC)));
return std::move(TS);
339}

341Expected<const CVIndexMap&> PDBLinker::mergeDebugT(ObjFile *File,
                                                 CVIndexMap &ObjectIndexMap) {
ScopedTimer T(TypeMergingTimer);

ArrayRef<uint8_t> Data = getDebugSection(File, ".debug$T");
if (Data.empty())
8
←
Assuming the condition is false→
9
←
Taking false branch→
  return ObjectIndexMap;

BinaryByteStream Stream(Data, support::little);
CVTypeArray Types;
BinaryStreamReader Reader(Stream);
if (auto EC = Reader.readArray(Types, Reader.getLength()))
10
←
Taking false branch→
  fatal("Reader::readArray failed: " + toString(std::move(EC)));

// Look through type servers. If we've already seen this type server, don't
// merge any type information.
if (Optional<TypeServer2Record> TS = maybeReadTypeServerRecord(Types))
11
←
Taking true branch→
  return maybeMergeTypeServerPDB(File, *TS);
12
←
Calling 'PDBLinker::maybeMergeTypeServerPDB'→

// This is a /Z7 object. Fill in the temporary, caller-provided
// ObjectIndexMap.
if (Config->DebugGHashes) {
  ArrayRef<GloballyHashedType> Hashes;
  std::vector<GloballyHashedType> OwnedHashes;
  if (Optional<ArrayRef<uint8_t>> DebugH = getDebugH(File))
    Hashes = getHashesFromDebugH(*DebugH);
  else {
    OwnedHashes = GloballyHashedType::hashTypes(Types);
    Hashes = OwnedHashes;
  }

  if (auto Err = mergeTypeAndIdRecords(GlobalIDTable, GlobalTypeTable,
                                       ObjectIndexMap.TPIMap, Types, Hashes))
    fatal("codeview::mergeTypeAndIdRecords failed: " +
          toString(std::move(Err)));
} else {
  if (auto Err = mergeTypeAndIdRecords(IDTable, TypeTable,
                                       ObjectIndexMap.TPIMap, Types))
    fatal("codeview::mergeTypeAndIdRecords failed: " +
          toString(std::move(Err)));
}
return ObjectIndexMap;
383}

385static Expected<std::unique_ptr<pdb::NativeSession>>
386tryToLoadPDB(const GUID &GuidFromObj, StringRef TSPath) {
// Ensure the file exists before anything else. We want to return ENOENT,
// "file not found", even if the path points to a removable device (in which
// case the return message would be EAGAIN, "resource unavailable try again")
if (!llvm::sys::fs::exists(TSPath))
  return errorCodeToError(std::error_code(ENOENT2, std::generic_category()));

ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr = MemoryBuffer::getFile(
    TSPath, /*FileSize=*/-1, /*RequiresNullTerminator=*/false);
if (!MBOrErr)
  return errorCodeToError(MBOrErr.getError());

std::unique_ptr<pdb::IPDBSession> ThisSession;
if (auto EC = pdb::NativeSession::createFromPdb(
        MemoryBuffer::getMemBuffer(Driver->takeBuffer(std::move(*MBOrErr)),
                                   /*RequiresNullTerminator=*/false),
        ThisSession))
  return std::move(EC);

std::unique_ptr<pdb::NativeSession> NS(
    static_cast<pdb::NativeSession *>(ThisSession.release()));
pdb::PDBFile &File = NS->getPDBFile();
auto ExpectedInfo = File.getPDBInfoStream();
// All PDB Files should have an Info stream.
if (!ExpectedInfo)
  return ExpectedInfo.takeError();

// Just because a file with a matching name was found and it was an actual
// PDB file doesn't mean it matches.  For it to match the InfoStream's GUID
// must match the GUID specified in the TypeServer2 record.
if (ExpectedInfo->getGuid() != GuidFromObj)
  return make_error<pdb::PDBError>(pdb::pdb_error_code::signature_out_of_date);

return std::move(NS);
420}

422Expected<const CVIndexMap &>
423PDBLinker::maybeMergeTypeServerPDB(ObjFile *File, TypeServer2Record &TS) {
const GUID &TSId = TS.getGuid();
StringRef TSPath = TS.getName();

// First, check if the PDB has previously failed to load.
auto PrevErr = MissingTypeServerPDBs.find(TSId);
if (PrevErr != MissingTypeServerPDBs.end())
13
←
Assuming the condition is true→
14
←
Taking true branch→
  return createFileError(
      TSPath,
      make_error<StringError>(PrevErr->second, inconvertibleErrorCode()));
15
←
Calling 'make_error<llvm::StringError, std::__cxx11::basic_string<char> &, std::error_code>'→

// Second, check if we already loaded a PDB with this GUID. Return the type
// index mapping if we have it.
auto Insertion = TypeServerIndexMappings.insert({TSId, CVIndexMap()});
CVIndexMap &IndexMap = Insertion.first->second;
if (!Insertion.second)
  return IndexMap;

// Mark this map as a type server map.
IndexMap.IsTypeServerMap = true;

// Check for a PDB at:
// 1. The given file path
// 2. Next to the object file or archive file
auto ExpectedSession = handleExpected(
    tryToLoadPDB(TSId, TSPath),
    [&]() {
      StringRef LocalPath =
          !File->ParentName.empty() ? File->ParentName : File->getName();
      SmallString<128> Path = sys::path::parent_path(LocalPath);
      // Currently, type server PDBs are only created by cl, which only runs
      // on Windows, so we can assume type server paths are Windows style.
      sys::path::append(
          Path, sys::path::filename(TSPath, sys::path::Style::windows));
      return tryToLoadPDB(TSId, Path);
    },
    [&](std::unique_ptr<ECError> EC) -> Error {
      auto SysErr = EC->convertToErrorCode();
      // Only re-try loading if the previous error was "No such file or
      // directory"
      if (SysErr.category() == std::generic_category() &&
          SysErr.value() == ENOENT2)
        return Error::success();
      return Error(std::move(EC));
    });

if (auto E = ExpectedSession.takeError()) {
  TypeServerIndexMappings.erase(TSId);

  // Flatten the error to a string, for later display, if the error occurs
  // again on the same PDB.
  std::string ErrMsg;
  raw_string_ostream S(ErrMsg);
  S << E;
  MissingTypeServerPDBs.emplace(TSId, S.str());

  return createFileError(TSPath, std::move(E));
}

pdb::NativeSession *Session = ExpectedSession->get();

// Keep a strong reference to this PDB, so that it's safe to hold pointers
// into the file.
LoadedPDBs.push_back(std::move(*ExpectedSession));

auto ExpectedTpi = Session->getPDBFile().getPDBTpiStream();
if (auto E = ExpectedTpi.takeError())
  fatal("Type server does not have TPI stream: " + toString(std::move(E)));
auto ExpectedIpi = Session->getPDBFile().getPDBIpiStream();
if (auto E = ExpectedIpi.takeError())
  fatal("Type server does not have TPI stream: " + toString(std::move(E)));

if (Config->DebugGHashes) {
  // PDBs do not actually store global hashes, so when merging a type server
  // PDB we have to synthesize global hashes.  To do this, we first synthesize
  // global hashes for the TPI stream, since it is independent, then we
  // synthesize hashes for the IPI stream, using the hashes for the TPI stream
  // as inputs.
  auto TpiHashes = GloballyHashedType::hashTypes(ExpectedTpi->typeArray());
  auto IpiHashes =
      GloballyHashedType::hashIds(ExpectedIpi->typeArray(), TpiHashes);

  // Merge TPI first, because the IPI stream will reference type indices.
  if (auto Err = mergeTypeRecords(GlobalTypeTable, IndexMap.TPIMap,
                                  ExpectedTpi->typeArray(), TpiHashes))
    fatal("codeview::mergeTypeRecords failed: " + toString(std::move(Err)));

  // Merge IPI.
  if (auto Err =
          mergeIdRecords(GlobalIDTable, IndexMap.TPIMap, IndexMap.IPIMap,
                         ExpectedIpi->typeArray(), IpiHashes))
    fatal("codeview::mergeIdRecords failed: " + toString(std::move(Err)));
} else {
  // Merge TPI first, because the IPI stream will reference type indices.
  if (auto Err = mergeTypeRecords(TypeTable, IndexMap.TPIMap,
                                  ExpectedTpi->typeArray()))
    fatal("codeview::mergeTypeRecords failed: " + toString(std::move(Err)));

  // Merge IPI.
  if (auto Err = mergeIdRecords(IDTable, IndexMap.TPIMap, IndexMap.IPIMap,
                                ExpectedIpi->typeArray()))
    fatal("codeview::mergeIdRecords failed: " + toString(std::move(Err)));
}

return IndexMap;
528}

530static bool remapTypeIndex(TypeIndex &TI, ArrayRef<TypeIndex> TypeIndexMap) {
if (TI.isSimple())
  return true;
if (TI.toArrayIndex() >= TypeIndexMap.size())
  return false;
TI = TypeIndexMap[TI.toArrayIndex()];
return true;
537}

539static void remapTypesInSymbolRecord(ObjFile *File, SymbolKind SymKind,
                                   MutableArrayRef<uint8_t> Contents,
                                   const CVIndexMap &IndexMap,
                                   ArrayRef<TiReference> TypeRefs) {
for (const TiReference &Ref : TypeRefs) {
  unsigned ByteSize = Ref.Count * sizeof(TypeIndex);
  if (Contents.size() < Ref.Offset + ByteSize)
    fatal("symbol record too short");

  // This can be an item index or a type index. Choose the appropriate map.
  ArrayRef<TypeIndex> TypeOrItemMap = IndexMap.TPIMap;
  bool IsItemIndex = Ref.Kind == TiRefKind::IndexRef;
  if (IsItemIndex && IndexMap.IsTypeServerMap)
    TypeOrItemMap = IndexMap.IPIMap;

  MutableArrayRef<TypeIndex> TIs(
      reinterpret_cast<TypeIndex *>(Contents.data() + Ref.Offset), Ref.Count);
  for (TypeIndex &TI : TIs) {
    if (!remapTypeIndex(TI, TypeOrItemMap)) {
      log("ignoring symbol record of kind 0x" + utohexstr(SymKind) + " in " +
          File->getName() + " with bad " + (IsItemIndex ? "item" : "type") +
          " index 0x" + utohexstr(TI.getIndex()));
      TI = TypeIndex(SimpleTypeKind::NotTranslated);
      continue;
    }
  }
}
566}

568static void
569recordStringTableReferenceAtOffset(MutableArrayRef<uint8_t> Contents,
                                 uint32_t Offset,
                                 std::vector<ulittle32_t *> &StrTableRefs) {
Contents =
    Contents.drop_front(Offset).take_front(sizeof(support::ulittle32_t));
ulittle32_t *Index = reinterpret_cast<ulittle32_t *>(Contents.data());
StrTableRefs.push_back(Index);
576}

578static void
579recordStringTableReferences(SymbolKind Kind, MutableArrayRef<uint8_t> Contents,
                          std::vector<ulittle32_t *> &StrTableRefs) {
// For now we only handle S_FILESTATIC, but we may need the same logic for
// S_DEFRANGE and S_DEFRANGE_SUBFIELD.  However, I cannot seem to generate any
// PDBs that contain these types of records, so because of the uncertainty
// they are omitted here until we can prove that it's necessary.
switch (Kind) {
case SymbolKind::S_FILESTATIC:
  // FileStaticSym::ModFileOffset
  recordStringTableReferenceAtOffset(Contents, 4, StrTableRefs);
  break;
case SymbolKind::S_DEFRANGE:
case SymbolKind::S_DEFRANGE_SUBFIELD:
  log("Not fixing up string table reference in S_DEFRANGE / "
      "S_DEFRANGE_SUBFIELD record");
  break;
default:
  break;
}
598}

600static SymbolKind symbolKind(ArrayRef<uint8_t> RecordData) {
const RecordPrefix *Prefix =
    reinterpret_cast<const RecordPrefix *>(RecordData.data());
return static_cast<SymbolKind>(uint16_t(Prefix->RecordKind));
604}

606/// MSVC translates S_PROC_ID_END to S_END, and S_[LG]PROC32_ID to S_[LG]PROC32
607static void translateIdSymbols(MutableArrayRef<uint8_t> &RecordData,
                             TypeCollection &IDTable) {
RecordPrefix *Prefix = reinterpret_cast<RecordPrefix *>(RecordData.data());

SymbolKind Kind = symbolKind(RecordData);

if (Kind == SymbolKind::S_PROC_ID_END) {
  Prefix->RecordKind = SymbolKind::S_END;
  return;
}

// In an object file, GPROC32_ID has an embedded reference which refers to the
// single object file type index namespace.  This has already been translated
// to the PDB file's ID stream index space, but we need to convert this to a
// symbol that refers to the type stream index space.  So we remap again from
// ID index space to type index space.
if (Kind == SymbolKind::S_GPROC32_ID || Kind == SymbolKind::S_LPROC32_ID) {
  SmallVector<TiReference, 1> Refs;
  auto Content = RecordData.drop_front(sizeof(RecordPrefix));
  CVSymbol Sym(Kind, RecordData);
  discoverTypeIndicesInSymbol(Sym, Refs);
  assert(Refs.size() == 1)((Refs.size() == 1) ? static_cast<void> (0) : __assert_fail
 ("Refs.size() == 1", "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 628, __PRETTY_FUNCTION__));
  assert(Refs.front().Count == 1)((Refs.front().Count == 1) ? static_cast<void> (0) : __assert_fail
 ("Refs.front().Count == 1", "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 629, __PRETTY_FUNCTION__));

  TypeIndex *TI =
      reinterpret_cast<TypeIndex *>(Content.data() + Refs[0].Offset);
  // `TI` is the index of a FuncIdRecord or MemberFuncIdRecord which lives in
  // the IPI stream, whose `FunctionType` member refers to the TPI stream.
  // Note that LF_FUNC_ID and LF_MEMFUNC_ID have the same record layout, and
  // in both cases we just need the second type index.
  if (!TI->isSimple() && !TI->isNoneType()) {
    CVType FuncIdData = IDTable.getType(*TI);
    SmallVector<TypeIndex, 2> Indices;
    discoverTypeIndices(FuncIdData, Indices);
    assert(Indices.size() == 2)((Indices.size() == 2) ? static_cast<void> (0) : __assert_fail
 ("Indices.size() == 2", "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 641, __PRETTY_FUNCTION__));
    *TI = Indices[1];
  }

  Kind = (Kind == SymbolKind::S_GPROC32_ID) ? SymbolKind::S_GPROC32
                                            : SymbolKind::S_LPROC32;
  Prefix->RecordKind = uint16_t(Kind);
}
649}

651/// Copy the symbol record. In a PDB, symbol records must be 4 byte aligned.
652/// The object file may not be aligned.
653static MutableArrayRef<uint8_t> copySymbolForPdb(const CVSymbol &Sym,
                                               BumpPtrAllocator &Alloc) {
size_t Size = alignTo(Sym.length(), alignOf(CodeViewContainer::Pdb));
assert(Size >= 4 && "record too short")((Size >= 4 && "record too short") ? static_cast<
void> (0) : __assert_fail ("Size >= 4 && \"record too short\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 656, __PRETTY_FUNCTION__));
assert(Size <= MaxRecordLength && "record too long")((Size <= MaxRecordLength && "record too long") ? static_cast
<void> (0) : __assert_fail ("Size <= MaxRecordLength && \"record too long\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 657, __PRETTY_FUNCTION__));
void *Mem = Alloc.Allocate(Size, 4);

// Copy the symbol record and zero out any padding bytes.
MutableArrayRef<uint8_t> NewData(reinterpret_cast<uint8_t *>(Mem), Size);
memcpy(NewData.data(), Sym.data().data(), Sym.length());
memset(NewData.data() + Sym.length(), 0, Size - Sym.length());

// Update the record prefix length. It should point to the beginning of the
// next record.
auto *Prefix = reinterpret_cast<RecordPrefix *>(Mem);
Prefix->RecordLen = Size - 2;
return NewData;
670}

672/// Return true if this symbol opens a scope. This implies that the symbol has
673/// "parent" and "end" fields, which contain the offset of the S_END or
674/// S_INLINESITE_END record.
675static bool symbolOpensScope(SymbolKind Kind) {
switch (Kind) {
case SymbolKind::S_GPROC32:
case SymbolKind::S_LPROC32:
case SymbolKind::S_LPROC32_ID:
case SymbolKind::S_GPROC32_ID:
case SymbolKind::S_BLOCK32:
case SymbolKind::S_SEPCODE:
case SymbolKind::S_THUNK32:
case SymbolKind::S_INLINESITE:
case SymbolKind::S_INLINESITE2:
  return true;
default:
  break;
}
return false;
691}

693static bool symbolEndsScope(SymbolKind Kind) {
switch (Kind) {
case SymbolKind::S_END:
case SymbolKind::S_PROC_ID_END:
case SymbolKind::S_INLINESITE_END:
  return true;
default:
  break;
}
return false;
703}

705struct ScopeRecord {
ulittle32_t PtrParent;
ulittle32_t PtrEnd;
708};

710struct SymbolScope {
ScopeRecord *OpeningRecord;
uint32_t ScopeOffset;
713};

715static void scopeStackOpen(SmallVectorImpl<SymbolScope> &Stack,
                         uint32_t CurOffset, CVSymbol &Sym) {
assert(symbolOpensScope(Sym.kind()))((symbolOpensScope(Sym.kind())) ? static_cast<void> (0)
 : __assert_fail ("symbolOpensScope(Sym.kind())", "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 717, __PRETTY_FUNCTION__));
SymbolScope S;
S.ScopeOffset = CurOffset;
S.OpeningRecord = const_cast<ScopeRecord *>(
    reinterpret_cast<const ScopeRecord *>(Sym.content().data()));
S.OpeningRecord->PtrParent = Stack.empty() ? 0 : Stack.back().ScopeOffset;
Stack.push_back(S);
724}

726static void scopeStackClose(SmallVectorImpl<SymbolScope> &Stack,
                          uint32_t CurOffset, ObjFile *File) {
if (Stack.empty()) {
  warn("symbol scopes are not balanced in " + File->getName());
  return;
}
SymbolScope S = Stack.pop_back_val();
S.OpeningRecord->PtrEnd = CurOffset;
734}

736static bool symbolGoesInModuleStream(const CVSymbol &Sym) {
switch (Sym.kind()) {
case SymbolKind::S_GDATA32:
case SymbolKind::S_CONSTANT:
case SymbolKind::S_UDT:
// We really should not be seeing S_PROCREF and S_LPROCREF in the first place
// since they are synthesized by the linker in response to S_GPROC32 and
// S_LPROC32, but if we do see them, don't put them in the module stream I
// guess.
case SymbolKind::S_PROCREF:
case SymbolKind::S_LPROCREF:
  return false;
// S_GDATA32 does not go in the module stream, but S_LDATA32 does.
case SymbolKind::S_LDATA32:
default:
  return true;
}
753}

755static bool symbolGoesInGlobalsStream(const CVSymbol &Sym) {
switch (Sym.kind()) {
case SymbolKind::S_CONSTANT:
case SymbolKind::S_GDATA32:
// S_LDATA32 goes in both the module stream and the globals stream.
case SymbolKind::S_LDATA32:
case SymbolKind::S_GPROC32:
case SymbolKind::S_LPROC32:
// We really should not be seeing S_PROCREF and S_LPROCREF in the first place
// since they are synthesized by the linker in response to S_GPROC32 and
// S_LPROC32, but if we do see them, copy them straight through.
case SymbolKind::S_PROCREF:
case SymbolKind::S_LPROCREF:
  return true;
// FIXME: For now, we drop all S_UDT symbols (i.e. they don't go in the
// globals stream or the modules stream).  These have special handling which
// needs more investigation before we can get right, but by putting them all
// into the globals stream WinDbg fails to display local variables of class
// types saying that it cannot find the type Foo *.  So as a stopgap just to
// keep things working, we drop them.
case SymbolKind::S_UDT:
default:
  return false;
}
779}

781static void addGlobalSymbol(pdb::GSIStreamBuilder &Builder, ObjFile &File,
                          const CVSymbol &Sym) {
switch (Sym.kind()) {
case SymbolKind::S_CONSTANT:
case SymbolKind::S_UDT:
case SymbolKind::S_GDATA32:
case SymbolKind::S_LDATA32:
case SymbolKind::S_PROCREF:
case SymbolKind::S_LPROCREF:
  Builder.addGlobalSymbol(Sym);
  break;
case SymbolKind::S_GPROC32:
case SymbolKind::S_LPROC32: {
  SymbolRecordKind K = SymbolRecordKind::ProcRefSym;
  if (Sym.kind() == SymbolKind::S_LPROC32)
    K = SymbolRecordKind::LocalProcRef;
  ProcRefSym PS(K);
  PS.Module = static_cast<uint16_t>(File.ModuleDBI->getModuleIndex());
  // For some reason, MSVC seems to add one to this value.
  ++PS.Module;
  PS.Name = getSymbolName(Sym);
  PS.SumName = 0;
  PS.SymOffset = File.ModuleDBI->getNextSymbolOffset();
  Builder.addGlobalSymbol(PS);
  break;
}
default:
  llvm_unreachable("Invalid symbol kind!")::llvm::llvm_unreachable_internal("Invalid symbol kind!", "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 808);
}
810}

812static void mergeSymbolRecords(BumpPtrAllocator &Alloc, ObjFile *File,
                             pdb::GSIStreamBuilder &GsiBuilder,
                             const CVIndexMap &IndexMap,
                             TypeCollection &IDTable,
                             std::vector<ulittle32_t *> &StringTableRefs,
                             BinaryStreamRef SymData) {
// FIXME: Improve error recovery by warning and skipping records when
// possible.
ArrayRef<uint8_t> SymsBuffer;
cantFail(SymData.readBytes(0, SymData.getLength(), SymsBuffer));
SmallVector<SymbolScope, 4> Scopes;

auto EC = forEachCodeViewRecord<CVSymbol>(
    SymsBuffer, [&](const CVSymbol &Sym) -> llvm::Error {
      // Discover type index references in the record. Skip it if we don't
      // know where they are.
      SmallVector<TiReference, 32> TypeRefs;
      if (!discoverTypeIndicesInSymbol(Sym, TypeRefs)) {
        log("ignoring unknown symbol record with kind 0x" +
            utohexstr(Sym.kind()));
        return Error::success();
      }

      // Copy the symbol record so we can mutate it.
      MutableArrayRef<uint8_t> NewData = copySymbolForPdb(Sym, Alloc);

      // Re-map all the type index references.
      MutableArrayRef<uint8_t> Contents =
          NewData.drop_front(sizeof(RecordPrefix));
      remapTypesInSymbolRecord(File, Sym.kind(), Contents, IndexMap,
                               TypeRefs);

      // An object file may have S_xxx_ID symbols, but these get converted to
      // "real" symbols in a PDB.
      translateIdSymbols(NewData, IDTable);

      // If this record refers to an offset in the object file's string table,
      // add that item to the global PDB string table and re-write the index.
      recordStringTableReferences(Sym.kind(), Contents, StringTableRefs);

      SymbolKind NewKind = symbolKind(NewData);

      // Fill in "Parent" and "End" fields by maintaining a stack of scopes.
      CVSymbol NewSym(NewKind, NewData);
      if (symbolOpensScope(NewKind))
        scopeStackOpen(Scopes, File->ModuleDBI->getNextSymbolOffset(),
                       NewSym);
      else if (symbolEndsScope(NewKind))
        scopeStackClose(Scopes, File->ModuleDBI->getNextSymbolOffset(), File);

      // Add the symbol to the globals stream if necessary.  Do this before
      // adding the symbol to the module since we may need to get the next
      // symbol offset, and writing to the module's symbol stream will update
      // that offset.
      if (symbolGoesInGlobalsStream(NewSym))
        addGlobalSymbol(GsiBuilder, *File, NewSym);

      // Add the symbol to the module.
      if (symbolGoesInModuleStream(NewSym))
        File->ModuleDBI->addSymbol(NewSym);
      return Error::success();
    });
cantFail(std::move(EC));
875}

877// Allocate memory for a .debug$S / .debug$F section and relocate it.
878static ArrayRef<uint8_t> relocateDebugChunk(BumpPtrAllocator &Alloc,
                                          SectionChunk &DebugChunk) {
uint8_t *Buffer = Alloc.Allocate<uint8_t>(DebugChunk.getSize());
assert(DebugChunk.OutputSectionOff == 0 &&((DebugChunk.OutputSectionOff == 0 && "debug sections should not be in output sections"
) ? static_cast<void> (0) : __assert_fail ("DebugChunk.OutputSectionOff == 0 && \"debug sections should not be in output sections\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 882, __PRETTY_FUNCTION__))
       "debug sections should not be in output sections")((DebugChunk.OutputSectionOff == 0 && "debug sections should not be in output sections"
) ? static_cast<void> (0) : __assert_fail ("DebugChunk.OutputSectionOff == 0 && \"debug sections should not be in output sections\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 882, __PRETTY_FUNCTION__));
DebugChunk.readRelocTargets();
DebugChunk.writeTo(Buffer);
return makeArrayRef(Buffer, DebugChunk.getSize());
886}

888static pdb::SectionContrib createSectionContrib(const Chunk *C, uint32_t Modi) {
OutputSection *OS = C->getOutputSection();
pdb::SectionContrib SC;
memset(&SC, 0, sizeof(SC));
SC.ISect = OS->SectionIndex;
SC.Off = C->getRVA() - OS->getRVA();
SC.Size = C->getSize();
if (auto *SecChunk = dyn_cast<SectionChunk>(C)) {
  SC.Characteristics = SecChunk->Header->Characteristics;
  SC.Imod = SecChunk->File->ModuleDBI->getModuleIndex();
  ArrayRef<uint8_t> Contents = SecChunk->getContents();
  JamCRC CRC(0);
  ArrayRef<char> CharContents = makeArrayRef(
      reinterpret_cast<const char *>(Contents.data()), Contents.size());
  CRC.update(CharContents);
  SC.DataCrc = CRC.getCRC();
} else {
  SC.Characteristics = OS->Header.Characteristics;
  // FIXME: When we start creating DBI for import libraries, use those here.
  SC.Imod = Modi;
}
SC.RelocCrc = 0; // FIXME

return SC;
912}

914static uint32_t
915translateStringTableIndex(uint32_t ObjIndex,
                        const DebugStringTableSubsectionRef &ObjStrTable,
                        DebugStringTableSubsection &PdbStrTable) {
auto ExpectedString = ObjStrTable.getString(ObjIndex);
if (!ExpectedString) {
  warn("Invalid string table reference");
  consumeError(ExpectedString.takeError());
  return 0;
}

return PdbStrTable.insert(*ExpectedString);
926}

928void DebugSHandler::handleDebugS(lld::coff::SectionChunk &DebugS) {
DebugSubsectionArray Subsections;

ArrayRef<uint8_t> RelocatedDebugContents = consumeDebugMagic(
    relocateDebugChunk(Linker.Alloc, DebugS), DebugS.getSectionName());

BinaryStreamReader Reader(RelocatedDebugContents, support::little);
ExitOnErr(Reader.readArray(Subsections, RelocatedDebugContents.size()));

for (const DebugSubsectionRecord &SS : Subsections) {
  switch (SS.kind()) {
  case DebugSubsectionKind::StringTable: {
    assert(!CVStrTab.valid() &&((!CVStrTab.valid() && "Encountered multiple string table subsections!"
) ? static_cast<void> (0) : __assert_fail ("!CVStrTab.valid() && \"Encountered multiple string table subsections!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 941, __PRETTY_FUNCTION__))
           "Encountered multiple string table subsections!")((!CVStrTab.valid() && "Encountered multiple string table subsections!"
) ? static_cast<void> (0) : __assert_fail ("!CVStrTab.valid() && \"Encountered multiple string table subsections!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 941, __PRETTY_FUNCTION__));
    ExitOnErr(CVStrTab.initialize(SS.getRecordData()));
    break;
  }
  case DebugSubsectionKind::FileChecksums:
    assert(!Checksums.valid() &&((!Checksums.valid() && "Encountered multiple checksum subsections!"
) ? static_cast<void> (0) : __assert_fail ("!Checksums.valid() && \"Encountered multiple checksum subsections!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 947, __PRETTY_FUNCTION__))
           "Encountered multiple checksum subsections!")((!Checksums.valid() && "Encountered multiple checksum subsections!"
) ? static_cast<void> (0) : __assert_fail ("!Checksums.valid() && \"Encountered multiple checksum subsections!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 947, __PRETTY_FUNCTION__));
    ExitOnErr(Checksums.initialize(SS.getRecordData()));
    break;
  case DebugSubsectionKind::Lines:
    // We can add the relocated line table directly to the PDB without
    // modification because the file checksum offsets will stay the same.
    File.ModuleDBI->addDebugSubsection(SS);
    break;
  case DebugSubsectionKind::FrameData: {
    // We need to re-write string table indices here, so save off all
    // frame data subsections until we've processed the entire list of
    // subsections so that we can be sure we have the string table.
    DebugFrameDataSubsectionRef FDS;
    ExitOnErr(FDS.initialize(SS.getRecordData()));
    NewFpoFrames.push_back(std::move(FDS));
    break;
  }
  case DebugSubsectionKind::Symbols:
    if (Config->DebugGHashes) {
      mergeSymbolRecords(Linker.Alloc, &File, Linker.Builder.getGsiBuilder(),
                         IndexMap, Linker.GlobalIDTable,
                         StringTableReferences, SS.getRecordData());
    } else {
      mergeSymbolRecords(Linker.Alloc, &File, Linker.Builder.getGsiBuilder(),
                         IndexMap, Linker.IDTable, StringTableReferences,
                         SS.getRecordData());
    }
    break;
  default:
    // FIXME: Process the rest of the subsections.
    break;
  }
}
980}

982void DebugSHandler::finish() {
pdb::DbiStreamBuilder &DbiBuilder = Linker.Builder.getDbiBuilder();

// We should have seen all debug subsections across the entire object file now
// which means that if a StringTable subsection and Checksums subsection were
// present, now is the time to handle them.
if (!CVStrTab.valid()) {
  if (Checksums.valid())
    fatal(".debug$S sections with a checksums subsection must also contain a "
          "string table subsection");

  if (!StringTableReferences.empty())
    warn("No StringTable subsection was encountered, but there are string "
         "table references");
  return;
}

// Rewrite string table indices in the Fpo Data and symbol records to refer to
// the global PDB string table instead of the object file string table.
for (DebugFrameDataSubsectionRef &FDS : NewFpoFrames) {
  const uint32_t *Reloc = FDS.getRelocPtr();
  for (codeview::FrameData FD : FDS) {
    FD.RvaStart += *Reloc;
    FD.FrameFunc =
        translateStringTableIndex(FD.FrameFunc, CVStrTab, Linker.PDBStrTab);
    DbiBuilder.addNewFpoData(FD);
  }
}

for (ulittle32_t *Ref : StringTableReferences)
  *Ref = translateStringTableIndex(*Ref, CVStrTab, Linker.PDBStrTab);

// Make a new file checksum table that refers to offsets in the PDB-wide
// string table. Generally the string table subsection appears after the
// checksum table, so we have to do this after looping over all the
// subsections.
auto NewChecksums = make_unique<DebugChecksumsSubsection>(Linker.PDBStrTab);
for (FileChecksumEntry &FC : Checksums) {
  SmallString<128> FileName =
      ExitOnErr(CVStrTab.getString(FC.FileNameOffset));
  pdbMakeAbsolute(FileName);
  ExitOnErr(Linker.Builder.getDbiBuilder().addModuleSourceFile(
      *File.ModuleDBI, FileName));
  NewChecksums->addChecksum(FileName, FC.Kind, FC.Checksum);
}
File.ModuleDBI->addDebugSubsection(std::move(NewChecksums));
1028}

1030void PDBLinker::addObjFile(ObjFile *File) {
// Add a module descriptor for every object file. We need to put an absolute
// path to the object into the PDB. If this is a plain object, we make its
// path absolute. If it's an object in an archive, we make the archive path
// absolute.
bool InArchive = !File->ParentName.empty();
3
←
Assuming the condition is false→
SmallString<128> Path = InArchive ? File->ParentName : File->getName();
4
←
'?' condition is false→
pdbMakeAbsolute(Path);
StringRef Name = InArchive ? File->getName() : StringRef(Path);
5
←
'?' condition is false→

pdb::DbiStreamBuilder &DbiBuilder = Builder.getDbiBuilder();
File->ModuleDBI = &ExitOnErr(DbiBuilder.addModuleInfo(Name));
File->ModuleDBI->setObjFileName(Path);

auto Chunks = File->getChunks();
uint32_t Modi = File->ModuleDBI->getModuleIndex();
for (Chunk *C : Chunks) {
6
←
Assuming '__begin1' is equal to '__end1'→
  auto *SecChunk = dyn_cast<SectionChunk>(C);
  if (!SecChunk || !SecChunk->Live)
    continue;
  pdb::SectionContrib SC = createSectionContrib(SecChunk, Modi);
  File->ModuleDBI->setFirstSectionContrib(SC);
  break;
}

// Before we can process symbol substreams from .debug$S, we need to process
// type information, file checksums, and the string table.  Add type info to
// the PDB first, so that we can get the map from object file type and item
// indices to PDB type and item indices.
CVIndexMap ObjectIndexMap;
auto IndexMapResult = mergeDebugT(File, ObjectIndexMap);
7
←
Calling 'PDBLinker::mergeDebugT'→

// If the .debug$T sections fail to merge, assume there is no debug info.
if (!IndexMapResult) {
  auto FileName = sys::path::filename(Path);
  warn("Cannot use debug info for '" + FileName + "'\n" +
       ">>> failed to load reference " +
       StringRef(toString(IndexMapResult.takeError())));
  return;
}

ScopedTimer T(SymbolMergingTimer);

DebugSHandler DSH(*this, *File, *IndexMapResult);
// Now do all live .debug$S and .debug$F sections.
for (SectionChunk *DebugChunk : File->getDebugChunks()) {
  if (!DebugChunk->Live || DebugChunk->getSize() == 0)
    continue;

  if (DebugChunk->getSectionName() == ".debug$S") {
    DSH.handleDebugS(*DebugChunk);
    continue;
  }

  if (DebugChunk->getSectionName() == ".debug$F") {
    ArrayRef<uint8_t> RelocatedDebugContents =
        relocateDebugChunk(Alloc, *DebugChunk);

    FixedStreamArray<object::FpoData> FpoRecords;
    BinaryStreamReader Reader(RelocatedDebugContents, support::little);
    uint32_t Count = RelocatedDebugContents.size() / sizeof(object::FpoData);
    ExitOnErr(Reader.readArray(FpoRecords, Count));

    // These are already relocated and don't refer to the string table, so we
    // can just copy it.
    for (const object::FpoData &FD : FpoRecords)
      DbiBuilder.addOldFpoData(FD);
    continue;
  }
}

// Do any post-processing now that all .debug$S sections have been processed.
DSH.finish();
1103}

1105static PublicSym32 createPublic(Defined *Def) {
PublicSym32 Pub(SymbolKind::S_PUB32);
Pub.Name = Def->getName();
if (auto *D = dyn_cast<DefinedCOFF>(Def)) {
  if (D->getCOFFSymbol().isFunctionDefinition())
    Pub.Flags = PublicSymFlags::Function;
} else if (isa<DefinedImportThunk>(Def)) {
  Pub.Flags = PublicSymFlags::Function;
}

OutputSection *OS = Def->getChunk()->getOutputSection();
assert(OS && "all publics should be in final image")((OS && "all publics should be in final image") ? static_cast
<void> (0) : __assert_fail ("OS && \"all publics should be in final image\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 1116, __PRETTY_FUNCTION__));
Pub.Offset = Def->getRVA() - OS->getRVA();
Pub.Segment = OS->SectionIndex;
return Pub;
1120}

1122// Add all object files to the PDB. Merge .debug$T sections into IpiData and
1123// TpiData.
1124void PDBLinker::addObjectsToPDB() {
ScopedTimer T1(AddObjectsTimer);
for (ObjFile *File : ObjFile::Instances)
  addObjFile(File);
2
←
Calling 'PDBLinker::addObjFile'→

Builder.getStringTableBuilder().setStrings(PDBStrTab);
T1.stop();

// Construct TPI and IPI stream contents.
ScopedTimer T2(TpiStreamLayoutTimer);
if (Config->DebugGHashes) {
  addTypeInfo(Builder.getTpiBuilder(), GlobalTypeTable);
  addTypeInfo(Builder.getIpiBuilder(), GlobalIDTable);
} else {
  addTypeInfo(Builder.getTpiBuilder(), TypeTable);
  addTypeInfo(Builder.getIpiBuilder(), IDTable);
}
T2.stop();

ScopedTimer T3(GlobalsLayoutTimer);
// Compute the public and global symbols.
auto &GsiBuilder = Builder.getGsiBuilder();
std::vector<PublicSym32> Publics;
Symtab->forEachSymbol([&Publics](Symbol *S) {
  // Only emit defined, live symbols that have a chunk.
  auto *Def = dyn_cast<Defined>(S);
  if (Def && Def->isLive() && Def->getChunk())
    Publics.push_back(createPublic(Def));
});

if (!Publics.empty()) {
  // Sort the public symbols and add them to the stream.
  std::sort(Publics.begin(), Publics.end(),
            [](const PublicSym32 &L, const PublicSym32 &R) {
              return L.Name < R.Name;
            });
  for (const PublicSym32 &Pub : Publics)
    GsiBuilder.addPublicSymbol(Pub);
}
1163}

1165void PDBLinker::addNatvisFiles() {
for (StringRef File : Config->NatvisFiles) {
  ErrorOr<std::unique_ptr<MemoryBuffer>> DataOrErr =
      MemoryBuffer::getFile(File);
  if (!DataOrErr) {
    warn("Cannot open input file: " + File);
    continue;
  }
  Builder.addInjectedSource(File, std::move(*DataOrErr));
}
1175}

1177static codeview::CPUType toCodeViewMachine(COFF::MachineTypes Machine) {
switch (Machine) {
case COFF::IMAGE_FILE_MACHINE_AMD64:
  return codeview::CPUType::X64;
case COFF::IMAGE_FILE_MACHINE_ARM:
  return codeview::CPUType::ARM7;
case COFF::IMAGE_FILE_MACHINE_ARM64:
  return codeview::CPUType::ARM64;
case COFF::IMAGE_FILE_MACHINE_ARMNT:
  return codeview::CPUType::ARMNT;
case COFF::IMAGE_FILE_MACHINE_I386:
  return codeview::CPUType::Intel80386;
default:
  llvm_unreachable("Unsupported CPU Type")::llvm::llvm_unreachable_internal("Unsupported CPU Type", "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 1190);
}
1192}

1194static void addCommonLinkerModuleSymbols(StringRef Path,
                                       pdb::DbiModuleDescriptorBuilder &Mod,
                                       BumpPtrAllocator &Allocator) {
ObjNameSym ONS(SymbolRecordKind::ObjNameSym);
Compile3Sym CS(SymbolRecordKind::Compile3Sym);
EnvBlockSym EBS(SymbolRecordKind::EnvBlockSym);

ONS.Name = "* Linker *";
ONS.Signature = 0;

CS.Machine = toCodeViewMachine(Config->Machine);
// Interestingly, if we set the string to 0.0.0.0, then when trying to view
// local variables WinDbg emits an error that private symbols are not present.
// By setting this to a valid MSVC linker version string, local variables are
// displayed properly.   As such, even though it is not representative of
// LLVM's version information, we need this for compatibility.
CS.Flags = CompileSym3Flags::None;
CS.VersionBackendBuild = 25019;
CS.VersionBackendMajor = 14;
CS.VersionBackendMinor = 10;
CS.VersionBackendQFE = 0;

// MSVC also sets the frontend to 0.0.0.0 since this is specifically for the
// linker module (which is by definition a backend), so we don't need to do
// anything here.  Also, it seems we can use "LLVM Linker" for the linker name
// without any problems.  Only the backend version has to be hardcoded to a
// magic number.
CS.VersionFrontendBuild = 0;
CS.VersionFrontendMajor = 0;
CS.VersionFrontendMinor = 0;
CS.VersionFrontendQFE = 0;
CS.Version = "LLVM Linker";
CS.setLanguage(SourceLanguage::Link);

ArrayRef<StringRef> Args = makeArrayRef(Config->Argv).drop_front();
std::string ArgStr = llvm::join(Args, " ");
EBS.Fields.push_back("cwd");
SmallString<64> cwd;
if (Config->PDBSourcePath.empty()) 
  sys::fs::current_path(cwd);
else
  cwd = Config->PDBSourcePath;
EBS.Fields.push_back(cwd);
EBS.Fields.push_back("exe");
SmallString<64> exe = Config->Argv[0];
pdbMakeAbsolute(exe);
EBS.Fields.push_back(exe);
EBS.Fields.push_back("pdb");
EBS.Fields.push_back(Path);
EBS.Fields.push_back("cmd");
EBS.Fields.push_back(ArgStr);
Mod.addSymbol(codeview::SymbolSerializer::writeOneSymbol(
    ONS, Allocator, CodeViewContainer::Pdb));
Mod.addSymbol(codeview::SymbolSerializer::writeOneSymbol(
    CS, Allocator, CodeViewContainer::Pdb));
Mod.addSymbol(codeview::SymbolSerializer::writeOneSymbol(
    EBS, Allocator, CodeViewContainer::Pdb));
1251}

1253static void addLinkerModuleSectionSymbol(pdb::DbiModuleDescriptorBuilder &Mod,
                                       OutputSection &OS,
                                       BumpPtrAllocator &Allocator) {
SectionSym Sym(SymbolRecordKind::SectionSym);
Sym.Alignment = 12; // 2^12 = 4KB
Sym.Characteristics = OS.Header.Characteristics;
Sym.Length = OS.getVirtualSize();
Sym.Name = OS.Name;
Sym.Rva = OS.getRVA();
Sym.SectionNumber = OS.SectionIndex;
Mod.addSymbol(codeview::SymbolSerializer::writeOneSymbol(
    Sym, Allocator, CodeViewContainer::Pdb));
1265}

1267// Creates a PDB file.
1268void coff::createPDB(SymbolTable *Symtab,
                   ArrayRef<OutputSection *> OutputSections,
                   ArrayRef<uint8_t> SectionTable,
                   llvm::codeview::DebugInfo *BuildId) {
ScopedTimer T1(TotalPdbLinkTimer);
PDBLinker PDB(Symtab);

PDB.initialize(BuildId);
PDB.addObjectsToPDB();
1
Calling 'PDBLinker::addObjectsToPDB'→
PDB.addSections(OutputSections, SectionTable);
PDB.addNatvisFiles();

ScopedTimer T2(DiskCommitTimer);
codeview::GUID Guid;
PDB.commit(&Guid);
memcpy(&BuildId->PDB70.Signature, &Guid, 16);
1284}

1286void PDBLinker::initialize(llvm::codeview::DebugInfo *BuildId) {
ExitOnErr(Builder.initialize(4096)); // 4096 is blocksize

BuildId->Signature.CVSignature = OMF::Signature::PDB70;
// Signature is set to a hash of the PDB contents when the PDB is done.
memset(BuildId->PDB70.Signature, 0, 16);
BuildId->PDB70.Age = 1;

// Create streams in MSF for predefined streams, namely
// PDB, TPI, DBI and IPI.
for (int I = 0; I < (int)pdb::kSpecialStreamCount; ++I)
  ExitOnErr(Builder.getMsfBuilder().addStream(0));

// Add an Info stream.
auto &InfoBuilder = Builder.getInfoBuilder();
InfoBuilder.setVersion(pdb::PdbRaw_ImplVer::PdbImplVC70);
InfoBuilder.setHashPDBContentsToGUID(true);

// Add an empty DBI stream.
pdb::DbiStreamBuilder &DbiBuilder = Builder.getDbiBuilder();
DbiBuilder.setAge(BuildId->PDB70.Age);
DbiBuilder.setVersionHeader(pdb::PdbDbiV70);
DbiBuilder.setMachineType(Config->Machine);
// Technically we are not link.exe 14.11, but there are known cases where
// debugging tools on Windows expect Microsoft-specific version numbers or
// they fail to work at all.  Since we know we produce PDBs that are
// compatible with LINK 14.11, we set that version number here.
DbiBuilder.setBuildNumber(14, 11);
1314}

1316void PDBLinker::addSections(ArrayRef<OutputSection *> OutputSections,
                          ArrayRef<uint8_t> SectionTable) {
// It's not entirely clear what this is, but the * Linker * module uses it.
pdb::DbiStreamBuilder &DbiBuilder = Builder.getDbiBuilder();
NativePath = Config->PDBPath;
pdbMakeAbsolute(NativePath);
uint32_t PdbFilePathNI = DbiBuilder.addECName(NativePath);
auto &LinkerModule = ExitOnErr(DbiBuilder.addModuleInfo("* Linker *"));
LinkerModule.setPdbFilePathNI(PdbFilePathNI);
addCommonLinkerModuleSymbols(NativePath, LinkerModule, Alloc);

// Add section contributions. They must be ordered by ascending RVA.
for (OutputSection *OS : OutputSections) {
  addLinkerModuleSectionSymbol(LinkerModule, *OS, Alloc);
  for (Chunk *C : OS->Chunks) {
    pdb::SectionContrib SC =
        createSectionContrib(C, LinkerModule.getModuleIndex());
    Builder.getDbiBuilder().addSectionContrib(SC);
  }
}

// Add Section Map stream.
ArrayRef<object::coff_section> Sections = {
    (const object::coff_section *)SectionTable.data(),
    SectionTable.size() / sizeof(object::coff_section)};
SectionMap = pdb::DbiStreamBuilder::createSectionMap(Sections);
DbiBuilder.setSectionMap(SectionMap);

// Add COFF section header stream.
ExitOnErr(
    DbiBuilder.addDbgStream(pdb::DbgHeaderType::SectionHdr, SectionTable));
1347}

1349void PDBLinker::commit(codeview::GUID *Guid) {
// Write to a file.
ExitOnErr(Builder.commit(Config->PDBPath, Guid));
1352}

1354static Expected<StringRef>
1355getFileName(const DebugStringTableSubsectionRef &Strings,
          const DebugChecksumsSubsectionRef &Checksums, uint32_t FileID) {
auto Iter = Checksums.getArray().at(FileID);
if (Iter == Checksums.getArray().end())
  return make_error<CodeViewError>(cv_error_code::no_records);
uint32_t Offset = Iter->FileNameOffset;
return Strings.getString(Offset);
1362}

1364static uint32_t getSecrelReloc() {
switch (Config->Machine) {
case AMD64:
  return COFF::IMAGE_REL_AMD64_SECREL;
case I386:
  return COFF::IMAGE_REL_I386_SECREL;
case ARMNT:
  return COFF::IMAGE_REL_ARM_SECREL;
case ARM64:
  return COFF::IMAGE_REL_ARM64_SECREL;
default:
  llvm_unreachable("unknown machine type")::llvm::llvm_unreachable_internal("unknown machine type", "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 1375);
}
1377}

1379// Try to find a line table for the given offset Addr into the given chunk C.
1380// If a line table was found, the line table, the string and checksum tables
1381// that are used to interpret the line table, and the offset of Addr in the line
1382// table are stored in the output arguments. Returns whether a line table was
1383// found.
1384static bool findLineTable(const SectionChunk *C, uint32_t Addr,
                        DebugStringTableSubsectionRef &CVStrTab,
                        DebugChecksumsSubsectionRef &Checksums,
                        DebugLinesSubsectionRef &Lines,
                        uint32_t &OffsetInLinetable) {
ExitOnError ExitOnErr;
uint32_t SecrelReloc = getSecrelReloc();

for (SectionChunk *DbgC : C->File->getDebugChunks()) {
  if (DbgC->getSectionName() != ".debug$S")
    continue;

  // Build a mapping of SECREL relocations in DbgC that refer to C.
  DenseMap<uint32_t, uint32_t> Secrels;
  for (const coff_relocation &R : DbgC->Relocs) {
    if (R.Type != SecrelReloc)
      continue;

    if (auto *S = dyn_cast_or_null<DefinedRegular>(
            C->File->getSymbols()[R.SymbolTableIndex]))
      if (S->getChunk() == C)
        Secrels[R.VirtualAddress] = S->getValue();
  }

  ArrayRef<uint8_t> Contents =
      consumeDebugMagic(DbgC->getContents(), ".debug$S");
  DebugSubsectionArray Subsections;
  BinaryStreamReader Reader(Contents, support::little);
  ExitOnErr(Reader.readArray(Subsections, Contents.size()));

  for (const DebugSubsectionRecord &SS : Subsections) {
    switch (SS.kind()) {
    case DebugSubsectionKind::StringTable: {
      assert(!CVStrTab.valid() &&((!CVStrTab.valid() && "Encountered multiple string table subsections!"
) ? static_cast<void> (0) : __assert_fail ("!CVStrTab.valid() && \"Encountered multiple string table subsections!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 1418, __PRETTY_FUNCTION__))
             "Encountered multiple string table subsections!")((!CVStrTab.valid() && "Encountered multiple string table subsections!"
) ? static_cast<void> (0) : __assert_fail ("!CVStrTab.valid() && \"Encountered multiple string table subsections!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 1418, __PRETTY_FUNCTION__));
      ExitOnErr(CVStrTab.initialize(SS.getRecordData()));
      break;
    }
    case DebugSubsectionKind::FileChecksums:
      assert(!Checksums.valid() &&((!Checksums.valid() && "Encountered multiple checksum subsections!"
) ? static_cast<void> (0) : __assert_fail ("!Checksums.valid() && \"Encountered multiple checksum subsections!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 1424, __PRETTY_FUNCTION__))
             "Encountered multiple checksum subsections!")((!Checksums.valid() && "Encountered multiple checksum subsections!"
) ? static_cast<void> (0) : __assert_fail ("!Checksums.valid() && \"Encountered multiple checksum subsections!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 1424, __PRETTY_FUNCTION__));
      ExitOnErr(Checksums.initialize(SS.getRecordData()));
      break;
    case DebugSubsectionKind::Lines: {
      ArrayRef<uint8_t> Bytes;
      auto Ref = SS.getRecordData();
      ExitOnErr(Ref.readLongestContiguousChunk(0, Bytes));
      size_t OffsetInDbgC = Bytes.data() - DbgC->getContents().data();

      // Check whether this line table refers to C.
      auto I = Secrels.find(OffsetInDbgC);
      if (I == Secrels.end())
        break;

      // Check whether this line table covers Addr in C.
      DebugLinesSubsectionRef LinesTmp;
      ExitOnErr(LinesTmp.initialize(BinaryStreamReader(Ref)));
      uint32_t OffsetInC = I->second + LinesTmp.header()->RelocOffset;
      if (Addr < OffsetInC || Addr >= OffsetInC + LinesTmp.header()->CodeSize)
        break;

      assert(!Lines.header() &&((!Lines.header() && "Encountered multiple line tables for function!"
) ? static_cast<void> (0) : __assert_fail ("!Lines.header() && \"Encountered multiple line tables for function!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 1446, __PRETTY_FUNCTION__))
             "Encountered multiple line tables for function!")((!Lines.header() && "Encountered multiple line tables for function!"
) ? static_cast<void> (0) : __assert_fail ("!Lines.header() && \"Encountered multiple line tables for function!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lld/COFF/PDB.cpp"
, 1446, __PRETTY_FUNCTION__));
      ExitOnErr(Lines.initialize(BinaryStreamReader(Ref)));
      OffsetInLinetable = Addr - OffsetInC;
      break;
    }
    default:
      break;
    }

    if (CVStrTab.valid() && Checksums.valid() && Lines.header())
      return true;
  }
}

return false;
1461}

1463// Use CodeView line tables to resolve a file and line number for the given
1464// offset into the given chunk and return them, or {"", 0} if a line table was
1465// not found.
1466std::pair<StringRef, uint32_t> coff::getFileLine(const SectionChunk *C,
                                               uint32_t Addr) {
ExitOnError ExitOnErr;

DebugStringTableSubsectionRef CVStrTab;
DebugChecksumsSubsectionRef Checksums;
DebugLinesSubsectionRef Lines;
uint32_t OffsetInLinetable;

if (!findLineTable(C, Addr, CVStrTab, Checksums, Lines, OffsetInLinetable))
  return {"", 0};

uint32_t NameIndex;
uint32_t LineNumber;
for (LineColumnEntry &Entry : Lines) {
  for (const LineNumberEntry &LN : Entry.LineNumbers) {
    if (LN.Offset > OffsetInLinetable) {
      StringRef Filename =
          ExitOnErr(getFileName(CVStrTab, Checksums, NameIndex));
      return {Filename, LineNumber};
    }
    LineInfo LI(LN.Flags);
    NameIndex = Entry.NameIndex;
    LineNumber = LI.getStartLine();
  }
}
StringRef Filename = ExitOnErr(getFileName(CVStrTab, Checksums, NameIndex));
return {Filename, LineNumber};
1494}

←

/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h

→

1//===- llvm/Support/Error.h - Recoverable error handling --------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file defines an API used to report recoverable errors.
11//
12//===----------------------------------------------------------------------===//
13 
14#ifndef LLVM_SUPPORT_ERROR_H
15#define LLVM_SUPPORT_ERROR_H
16 
17#include "llvm-c/Error.h"
18#include "llvm/ADT/STLExtras.h"
19#include "llvm/ADT/SmallVector.h"
20#include "llvm/ADT/StringExtras.h"
21#include "llvm/ADT/Twine.h"
22#include "llvm/Config/abi-breaking.h"
23#include "llvm/Support/AlignOf.h"
24#include "llvm/Support/Compiler.h"
25#include "llvm/Support/Debug.h"
26#include "llvm/Support/ErrorHandling.h"
27#include "llvm/Support/ErrorOr.h"
28#include "llvm/Support/Format.h"
29#include "llvm/Support/raw_ostream.h"
30#include <algorithm>
31#include <cassert>
32#include <cstdint>
33#include <cstdlib>
34#include <functional>
35#include <memory>
36#include <new>
37#include <string>
38#include <system_error>
39#include <type_traits>
40#include <utility>
41#include <vector>
42 
43namespace llvm {
44 
45class ErrorSuccess;
46 
47/// Base class for error info classes. Do not extend this directly: Extend
48/// the ErrorInfo template subclass instead.
49class ErrorInfoBase {
50public:
51  virtual ~ErrorInfoBase() = default;
52 
53  /// Print an error message to an output stream.
54  virtual void log(raw_ostream &OS) const = 0;
55 
56  /// Return the error message as a string.
57  virtual std::string message() const {
58    std::string Msg;
59    raw_string_ostream OS(Msg);
60    log(OS);
61    return OS.str();
62  }
63 
64  /// Convert this error to a std::error_code.
65  ///
66  /// This is a temporary crutch to enable interaction with code still
67  /// using std::error_code. It will be removed in the future.
68  virtual std::error_code convertToErrorCode() const = 0;
69 
70  // Returns the class ID for this type.
71  static const void *classID() { return &ID; }
72 
73  // Returns the class ID for the dynamic type of this ErrorInfoBase instance.
74  virtual const void *dynamicClassID() const = 0;
75 
76  // Check whether this instance is a subclass of the class identified by
77  // ClassID.
78  virtual bool isA(const void *const ClassID) const {
79    return ClassID == classID();
80  }
81 
82  // Check whether this instance is a subclass of ErrorInfoT.
83  template <typename ErrorInfoT> bool isA() const {
84    return isA(ErrorInfoT::classID());
85  }
86 
87private:
88  virtual void anchor();
89 
90  static char ID;
91};
92 
93/// Lightweight error class with error context and mandatory checking.
94///
95/// Instances of this class wrap a ErrorInfoBase pointer. Failure states
96/// are represented by setting the pointer to a ErrorInfoBase subclass
97/// instance containing information describing the failure. Success is
98/// represented by a null pointer value.
99///
100/// Instances of Error also contains a 'Checked' flag, which must be set
101/// before the destructor is called, otherwise the destructor will trigger a
102/// runtime error. This enforces at runtime the requirement that all Error
103/// instances be checked or returned to the caller.
104///
105/// There are two ways to set the checked flag, depending on what state the
106/// Error instance is in. For Error instances indicating success, it
107/// is sufficient to invoke the boolean conversion operator. E.g.:
108///
109///   @code{.cpp}
110///   Error foo(<...>);
111///
112///   if (auto E = foo(<...>))
113///     return E; // <- Return E if it is in the error state.
114///   // We have verified that E was in the success state. It can now be safely
115///   // destroyed.
116///   @endcode
117///
118/// A success value *can not* be dropped. For example, just calling 'foo(<...>)'
119/// without testing the return value will raise a runtime error, even if foo
120/// returns success.
121///
122/// For Error instances representing failure, you must use either the
123/// handleErrors or handleAllErrors function with a typed handler. E.g.:
124///
125///   @code{.cpp}
126///   class MyErrorInfo : public ErrorInfo<MyErrorInfo> {
127///     // Custom error info.
128///   };
129///
130///   Error foo(<...>) { return make_error<MyErrorInfo>(...); }
131///
132///   auto E = foo(<...>); // <- foo returns failure with MyErrorInfo.
133///   auto NewE =
134///     handleErrors(E,
135///       [](const MyErrorInfo &M) {
136///         // Deal with the error.
137///       },
138///       [](std::unique_ptr<OtherError> M) -> Error {
139///         if (canHandle(*M)) {
140///           // handle error.
141///           return Error::success();
142///         }
143///         // Couldn't handle this error instance. Pass it up the stack.
144///         return Error(std::move(M));
145///       );
146///   // Note - we must check or return NewE in case any of the handlers
147///   // returned a new error.
148///   @endcode
149///
150/// The handleAllErrors function is identical to handleErrors, except
151/// that it has a void return type, and requires all errors to be handled and
152/// no new errors be returned. It prevents errors (assuming they can all be
153/// handled) from having to be bubbled all the way to the top-level.
154///
155/// *All* Error instances must be checked before destruction, even if
156/// they're moved-assigned or constructed from Success values that have already
157/// been checked. This enforces checking through all levels of the call stack.
158class LLVM_NODISCARD[[clang::warn_unused_result]] Error {
159  // Both ErrorList and FileError need to be able to yank ErrorInfoBase
160  // pointers out of this class to add to the error list.
161  friend class ErrorList;
162  friend class FileError;
163 
164  // handleErrors needs to be able to set the Checked flag.
165  template <typename... HandlerTs>
166  friend Error handleErrors(Error E, HandlerTs &&... Handlers);
167 
168  // Expected<T> needs to be able to steal the payload when constructed from an
169  // error.
170  template <typename T> friend class Expected;
171 
172  // wrap needs to be able to steal the payload.
173  friend LLVMErrorRef wrap(Error);
174 
175protected:
176  /// Create a success value. Prefer using 'Error::success()' for readability
177  Error() {
178    setPtr(nullptr);
179    setChecked(false);
180  }
181 
182public:
183  /// Create a success value.
184  static ErrorSuccess success();
185 
186  // Errors are not copy-constructable.
187  Error(const Error &Other) = delete;
188 
189  /// Move-construct an error value. The newly constructed error is considered
190  /// unchecked, even if the source error had been checked. The original error
191  /// becomes a checked Success value, regardless of its original state.
192  Error(Error &&Other) {
193    setChecked(true);
194    *this = std::move(Other);
195  }
196 
197  /// Create an error value. Prefer using the 'make_error' function, but
198  /// this constructor can be useful when "re-throwing" errors from handlers.
199  Error(std::unique_ptr<ErrorInfoBase> Payload) {
200    setPtr(Payload.release());
201    setChecked(false);
20
←
Potential leak of memory pointed to by 'Payload._M_t._M_head_impl'
202  }
203 
204  // Errors are not copy-assignable.
205  Error &operator=(const Error &Other) = delete;
206 
207  /// Move-assign an error value. The current error must represent success, you
208  /// you cannot overwrite an unhandled error. The current error is then
209  /// considered unchecked. The source error becomes a checked success value,
210  /// regardless of its original state.
211  Error &operator=(Error &&Other) {
212    // Don't allow overwriting of unchecked values.
213    assertIsChecked();
214    setPtr(Other.getPtr());
215 
216    // This Error is unchecked, even if the source error was checked.
217    setChecked(false);
218 
219    // Null out Other's payload and set its checked bit.
220    Other.setPtr(nullptr);
221    Other.setChecked(true);
222 
223    return *this;
224  }
225 
226  /// Destroy a Error. Fails with a call to abort() if the error is
227  /// unchecked.
228  ~Error() {
229    assertIsChecked();
230    delete getPtr();
231  }
232 
233  /// Bool conversion. Returns true if this Error is in a failure state,
234  /// and false if it is in an accept state. If the error is in a Success state
235  /// it will be considered checked.
236  explicit operator bool() {
237    setChecked(getPtr() == nullptr);
238    return getPtr() != nullptr;
239  }
240 
241  /// Check whether one error is a subclass of another.
242  template <typename ErrT> bool isA() const {
243    return getPtr() && getPtr()->isA(ErrT::classID());
244  }
245 
246  /// Returns the dynamic class id of this error, or null if this is a success
247  /// value.
248  const void* dynamicClassID() const {
249    if (!getPtr())
250      return nullptr;
251    return getPtr()->dynamicClassID();
252  }
253 
254private:
255#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
256  // assertIsChecked() happens very frequently, but under normal circumstances
257  // is supposed to be a no-op.  So we want it to be inlined, but having a bunch
258  // of debug prints can cause the function to be too large for inlining.  So
259  // it's important that we define this function out of line so that it can't be
260  // inlined.
261  LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn))
262  void fatalUncheckedError() const;
263#endif
264 
265  void assertIsChecked() {
266#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
267    if (LLVM_UNLIKELY(!getChecked() || getPtr())__builtin_expect((bool)(!getChecked() || getPtr()), false))
268      fatalUncheckedError();
269#endif
270  }
271 
272  ErrorInfoBase *getPtr() const {
273    return reinterpret_cast<ErrorInfoBase*>(
274             reinterpret_cast<uintptr_t>(Payload) &
275             ~static_cast<uintptr_t>(0x1));
276  }
277 
278  void setPtr(ErrorInfoBase *EI) {
279#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
280    Payload = reinterpret_cast<ErrorInfoBase*>(
281                (reinterpret_cast<uintptr_t>(EI) &
282                 ~static_cast<uintptr_t>(0x1)) |
283                (reinterpret_cast<uintptr_t>(Payload) & 0x1));
284#else
285    Payload = EI;
286#endif
287  }
288 
289  bool getChecked() const {
290#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
291    return (reinterpret_cast<uintptr_t>(Payload) & 0x1) == 0;
292#else
293    return true;
294#endif
295  }
296 
297  void setChecked(bool V) {
298    Payload = reinterpret_cast<ErrorInfoBase*>(
299                (reinterpret_cast<uintptr_t>(Payload) &
300                  ~static_cast<uintptr_t>(0x1)) |
301                  (V ? 0 : 1));
302  }
303 
304  std::unique_ptr<ErrorInfoBase> takePayload() {
305    std::unique_ptr<ErrorInfoBase> Tmp(getPtr());
306    setPtr(nullptr);
307    setChecked(true);
308    return Tmp;
309  }
310 
311  friend raw_ostream &operator<<(raw_ostream &OS, const Error &E) {
312    if (auto P = E.getPtr())
313      P->log(OS);
314    else
315      OS << "success";
316    return OS;
317  }
318 
319  ErrorInfoBase *Payload = nullptr;
320};
321 
322/// Subclass of Error for the sole purpose of identifying the success path in
323/// the type system. This allows to catch invalid conversion to Expected<T> at
324/// compile time.
325class ErrorSuccess final : public Error {};
326 
327inline ErrorSuccess Error::success() { return ErrorSuccess(); }
328 
329/// Make a Error instance representing failure using the given error info
330/// type.
331template <typename ErrT, typename... ArgTs> Error make_error(ArgTs &&... Args) {
332  return Error(llvm::make_unique<ErrT>(std::forward<ArgTs>(Args)...));
16
←
Calling 'make_unique<llvm::StringError, std::__cxx11::basic_string<char> &, std::error_code>'→
18
←
Returned allocated memory→
19
←
Calling constructor for 'Error'→
333}
334 
335/// Base class for user error types. Users should declare their error types
336/// like:
337///
338/// class MyError : public ErrorInfo<MyError> {
339///   ....
340/// };
341///
342/// This class provides an implementation of the ErrorInfoBase::kind
343/// method, which is used by the Error RTTI system.
344template <typename ThisErrT, typename ParentErrT = ErrorInfoBase>
345class ErrorInfo : public ParentErrT {
346public:
347  using ParentErrT::ParentErrT; // inherit constructors
348 
349  static const void *classID() { return &ThisErrT::ID; }
350 
351  const void *dynamicClassID() const override { return &ThisErrT::ID; }
352 
353  bool isA(const void *const ClassID) const override {
354    return ClassID == classID() || ParentErrT::isA(ClassID);
355  }
356};
357 
358/// Special ErrorInfo subclass representing a list of ErrorInfos.
359/// Instances of this class are constructed by joinError.
360class ErrorList final : public ErrorInfo<ErrorList> {
361  // handleErrors needs to be able to iterate the payload list of an
362  // ErrorList.
363  template <typename... HandlerTs>
364  friend Error handleErrors(Error E, HandlerTs &&... Handlers);
365 
366  // joinErrors is implemented in terms of join.
367  friend Error joinErrors(Error, Error);
368 
369public:
370  void log(raw_ostream &OS) const override {
371    OS << "Multiple errors:\n";
372    for (auto &ErrPayload : Payloads) {
373      ErrPayload->log(OS);
374      OS << "\n";
375    }
376  }
377 
378  std::error_code convertToErrorCode() const override;
379 
380  // Used by ErrorInfo::classID.
381  static char ID;
382 
383private:
384  ErrorList(std::unique_ptr<ErrorInfoBase> Payload1,
385            std::unique_ptr<ErrorInfoBase> Payload2) {
386    assert(!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() &&((!Payload1->isA<ErrorList>() && !Payload2->
isA<ErrorList>() && "ErrorList constructor payloads should be singleton errors"
) ? static_cast<void> (0) : __assert_fail ("!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() && \"ErrorList constructor payloads should be singleton errors\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 387, __PRETTY_FUNCTION__))
387           "ErrorList constructor payloads should be singleton errors")((!Payload1->isA<ErrorList>() && !Payload2->
isA<ErrorList>() && "ErrorList constructor payloads should be singleton errors"
) ? static_cast<void> (0) : __assert_fail ("!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() && \"ErrorList constructor payloads should be singleton errors\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 387, __PRETTY_FUNCTION__));
388    Payloads.push_back(std::move(Payload1));
389    Payloads.push_back(std::move(Payload2));
390  }
391 
392  static Error join(Error E1, Error E2) {
393    if (!E1)
394      return E2;
395    if (!E2)
396      return E1;
397    if (E1.isA<ErrorList>()) {
398      auto &E1List = static_cast<ErrorList &>(*E1.getPtr());
399      if (E2.isA<ErrorList>()) {
400        auto E2Payload = E2.takePayload();
401        auto &E2List = static_cast<ErrorList &>(*E2Payload);
402        for (auto &Payload : E2List.Payloads)
403          E1List.Payloads.push_back(std::move(Payload));
404      } else
405        E1List.Payloads.push_back(E2.takePayload());
406 
407      return E1;
408    }
409    if (E2.isA<ErrorList>()) {
410      auto &E2List = static_cast<ErrorList &>(*E2.getPtr());
411      E2List.Payloads.insert(E2List.Payloads.begin(), E1.takePayload());
412      return E2;
413    }
414    return Error(std::unique_ptr<ErrorList>(
415        new ErrorList(E1.takePayload(), E2.takePayload())));
416  }
417 
418  std::vector<std::unique_ptr<ErrorInfoBase>> Payloads;
419};
420 
421/// Concatenate errors. The resulting Error is unchecked, and contains the
422/// ErrorInfo(s), if any, contained in E1, followed by the
423/// ErrorInfo(s), if any, contained in E2.
424inline Error joinErrors(Error E1, Error E2) {
425  return ErrorList::join(std::move(E1), std::move(E2));
426}
427 
428/// Tagged union holding either a T or a Error.
429///
430/// This class parallels ErrorOr, but replaces error_code with Error. Since
431/// Error cannot be copied, this class replaces getError() with
432/// takeError(). It also adds an bool errorIsA<ErrT>() method for testing the
433/// error class type.
434template <class T> class LLVM_NODISCARD[[clang::warn_unused_result]] Expected {
435  template <class T1> friend class ExpectedAsOutParameter;
436  template <class OtherT> friend class Expected;
437 
438  static const bool isRef = std::is_reference<T>::value;
439 
440  using wrap = std::reference_wrapper<typename std::remove_reference<T>::type>;
441 
442  using error_type = std::unique_ptr<ErrorInfoBase>;
443 
444public:
445  using storage_type = typename std::conditional<isRef, wrap, T>::type;
446  using value_type = T;
447 
448private:
449  using reference = typename std::remove_reference<T>::type &;
450  using const_reference = const typename std::remove_reference<T>::type &;
451  using pointer = typename std::remove_reference<T>::type *;
452  using const_pointer = const typename std::remove_reference<T>::type *;
453 
454public:
455  /// Create an Expected<T> error value from the given Error.
456  Expected(Error Err)
457      : HasError(true)
458#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
459        // Expected is unchecked upon construction in Debug builds.
460        , Unchecked(true)
461#endif
462  {
463    assert(Err && "Cannot create Expected<T> from Error success value.")((Err && "Cannot create Expected<T> from Error success value."
) ? static_cast<void> (0) : __assert_fail ("Err && \"Cannot create Expected<T> from Error success value.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 463, __PRETTY_FUNCTION__));
464    new (getErrorStorage()) error_type(Err.takePayload());
465  }
466 
467  /// Forbid to convert from Error::success() implicitly, this avoids having
468  /// Expected<T> foo() { return Error::success(); } which compiles otherwise
469  /// but triggers the assertion above.
470  Expected(ErrorSuccess) = delete;
471 
472  /// Create an Expected<T> success value from the given OtherT value, which
473  /// must be convertible to T.
474  template <typename OtherT>
475  Expected(OtherT &&Val,
476           typename std::enable_if<std::is_convertible<OtherT, T>::value>::type
477               * = nullptr)
478      : HasError(false)
479#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
480        // Expected is unchecked upon construction in Debug builds.
481        , Unchecked(true)
482#endif
483  {
484    new (getStorage()) storage_type(std::forward<OtherT>(Val));
485  }
486 
487  /// Move construct an Expected<T> value.
488  Expected(Expected &&Other) { moveConstruct(std::move(Other)); }
489 
490  /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
491  /// must be convertible to T.
492  template <class OtherT>
493  Expected(Expected<OtherT> &&Other,
494           typename std::enable_if<std::is_convertible<OtherT, T>::value>::type
495               * = nullptr) {
496    moveConstruct(std::move(Other));
497  }
498 
499  /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
500  /// isn't convertible to T.
501  template <class OtherT>
502  explicit Expected(
503      Expected<OtherT> &&Other,
504      typename std::enable_if<!std::is_convertible<OtherT, T>::value>::type * =
505          nullptr) {
506    moveConstruct(std::move(Other));
507  }
508 
509  /// Move-assign from another Expected<T>.
510  Expected &operator=(Expected &&Other) {
511    moveAssign(std::move(Other));
512    return *this;
513  }
514 
515  /// Destroy an Expected<T>.
516  ~Expected() {
517    assertIsChecked();
518    if (!HasError)
519      getStorage()->~storage_type();
520    else
521      getErrorStorage()->~error_type();
522  }
523 
524  /// Return false if there is an error.
525  explicit operator bool() {
526#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
527    Unchecked = HasError;
528#endif
529    return !HasError;
530  }
531 
532  /// Returns a reference to the stored T value.
533  reference get() {
534    assertIsChecked();
535    return *getStorage();
536  }
537 
538  /// Returns a const reference to the stored T value.
539  const_reference get() const {
540    assertIsChecked();
541    return const_cast<Expected<T> *>(this)->get();
542  }
543 
544  /// Check that this Expected<T> is an error of type ErrT.
545  template <typename ErrT> bool errorIsA() const {
546    return HasError && (*getErrorStorage())->template isA<ErrT>();
547  }
548 
549  /// Take ownership of the stored error.
550  /// After calling this the Expected<T> is in an indeterminate state that can
551  /// only be safely destructed. No further calls (beside the destructor) should
552  /// be made on the Expected<T> vaule.
553  Error takeError() {
554#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
555    Unchecked = false;
556#endif
557    return HasError ? Error(std::move(*getErrorStorage())) : Error::success();
558  }
559 
560  /// Returns a pointer to the stored T value.
561  pointer operator->() {
562    assertIsChecked();
563    return toPointer(getStorage());
564  }
565 
566  /// Returns a const pointer to the stored T value.
567  const_pointer operator->() const {
568    assertIsChecked();
569    return toPointer(getStorage());
570  }
571 
572  /// Returns a reference to the stored T value.
573  reference operator*() {
574    assertIsChecked();
575    return *getStorage();
576  }
577 
578  /// Returns a const reference to the stored T value.
579  const_reference operator*() const {
580    assertIsChecked();
581    return *getStorage();
582  }
583 
584private:
585  template <class T1>
586  static bool compareThisIfSameType(const T1 &a, const T1 &b) {
587    return &a == &b;
588  }
589 
590  template <class T1, class T2>
591  static bool compareThisIfSameType(const T1 &a, const T2 &b) {
592    return false;
593  }
594 
595  template <class OtherT> void moveConstruct(Expected<OtherT> &&Other) {
596    HasError = Other.HasError;
597#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
598    Unchecked = true;
599    Other.Unchecked = false;
600#endif
601 
602    if (!HasError)
603      new (getStorage()) storage_type(std::move(*Other.getStorage()));
604    else
605      new (getErrorStorage()) error_type(std::move(*Other.getErrorStorage()));
606  }
607 
608  template <class OtherT> void moveAssign(Expected<OtherT> &&Other) {
609    assertIsChecked();
610 
611    if (compareThisIfSameType(*this, Other))
612      return;
613 
614    this->~Expected();
615    new (this) Expected(std::move(Other));
616  }
617 
618  pointer toPointer(pointer Val) { return Val; }
619 
620  const_pointer toPointer(const_pointer Val) const { return Val; }
621 
622  pointer toPointer(wrap *Val) { return &Val->get(); }
623 
624  const_pointer toPointer(const wrap *Val) const { return &Val->get(); }
625 
626  storage_type *getStorage() {
627    assert(!HasError && "Cannot get value when an error exists!")((!HasError && "Cannot get value when an error exists!"
) ? static_cast<void> (0) : __assert_fail ("!HasError && \"Cannot get value when an error exists!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 627, __PRETTY_FUNCTION__));
628    return reinterpret_cast<storage_type *>(TStorage.buffer);
629  }
630 
631  const storage_type *getStorage() const {
632    assert(!HasError && "Cannot get value when an error exists!")((!HasError && "Cannot get value when an error exists!"
) ? static_cast<void> (0) : __assert_fail ("!HasError && \"Cannot get value when an error exists!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 632, __PRETTY_FUNCTION__));
633    return reinterpret_cast<const storage_type *>(TStorage.buffer);
634  }
635 
636  error_type *getErrorStorage() {
637    assert(HasError && "Cannot get error when a value exists!")((HasError && "Cannot get error when a value exists!"
) ? static_cast<void> (0) : __assert_fail ("HasError && \"Cannot get error when a value exists!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 637, __PRETTY_FUNCTION__));
638    return reinterpret_cast<error_type *>(ErrorStorage.buffer);
639  }
640 
641  const error_type *getErrorStorage() const {
642    assert(HasError && "Cannot get error when a value exists!")((HasError && "Cannot get error when a value exists!"
) ? static_cast<void> (0) : __assert_fail ("HasError && \"Cannot get error when a value exists!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 642, __PRETTY_FUNCTION__));
643    return reinterpret_cast<const error_type *>(ErrorStorage.buffer);
644  }
645 
646  // Used by ExpectedAsOutParameter to reset the checked flag.
647  void setUnchecked() {
648#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
649    Unchecked = true;
650#endif
651  }
652 
653#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
654  LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn))
655  LLVM_ATTRIBUTE_NOINLINE__attribute__((noinline))
656  void fatalUncheckedExpected() const {
657    dbgs() << "Expected<T> must be checked before access or destruction.\n";
658    if (HasError) {
659      dbgs() << "Unchecked Expected<T> contained error:\n";
660      (*getErrorStorage())->log(dbgs());
661    } else
662      dbgs() << "Expected<T> value was in success state. (Note: Expected<T> "
663                "values in success mode must still be checked prior to being "
664                "destroyed).\n";
665    abort();
666  }
667#endif
668 
669  void assertIsChecked() {
670#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
671    if (LLVM_UNLIKELY(Unchecked)__builtin_expect((bool)(Unchecked), false))
672      fatalUncheckedExpected();
673#endif
674  }
675 
676  union {
677    AlignedCharArrayUnion<storage_type> TStorage;
678    AlignedCharArrayUnion<error_type> ErrorStorage;
679  };
680  bool HasError : 1;
681#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
682  bool Unchecked : 1;
683#endif
684};
685 
686/// Report a serious error, calling any installed error handler. See
687/// ErrorHandling.h.
688LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) void report_fatal_error(Error Err,
689                                                bool gen_crash_diag = true);
690 
691/// Report a fatal error if Err is a failure value.
692///
693/// This function can be used to wrap calls to fallible functions ONLY when it
694/// is known that the Error will always be a success value. E.g.
695///
696///   @code{.cpp}
697///   // foo only attempts the fallible operation if DoFallibleOperation is
698///   // true. If DoFallibleOperation is false then foo always returns
699///   // Error::success().
700///   Error foo(bool DoFallibleOperation);
701///
702///   cantFail(foo(false));
703///   @endcode
704inline void cantFail(Error Err, const char *Msg = nullptr) {
705  if (Err) {
706    if (!Msg)
707      Msg = "Failure value returned from cantFail wrapped call";
708    llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 708);
709  }
710}
711 
712/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
713/// returns the contained value.
714///
715/// This function can be used to wrap calls to fallible functions ONLY when it
716/// is known that the Error will always be a success value. E.g.
717///
718///   @code{.cpp}
719///   // foo only attempts the fallible operation if DoFallibleOperation is
720///   // true. If DoFallibleOperation is false then foo always returns an int.
721///   Expected<int> foo(bool DoFallibleOperation);
722///
723///   int X = cantFail(foo(false));
724///   @endcode
725template <typename T>
726T cantFail(Expected<T> ValOrErr, const char *Msg = nullptr) {
727  if (ValOrErr)
728    return std::move(*ValOrErr);
729  else {
730    if (!Msg)
731      Msg = "Failure value returned from cantFail wrapped call";
732    llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 732);
733  }
734}
735 
736/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
737/// returns the contained reference.
738///
739/// This function can be used to wrap calls to fallible functions ONLY when it
740/// is known that the Error will always be a success value. E.g.
741///
742///   @code{.cpp}
743///   // foo only attempts the fallible operation if DoFallibleOperation is
744///   // true. If DoFallibleOperation is false then foo always returns a Bar&.
745///   Expected<Bar&> foo(bool DoFallibleOperation);
746///
747///   Bar &X = cantFail(foo(false));
748///   @endcode
749template <typename T>
750T& cantFail(Expected<T&> ValOrErr, const char *Msg = nullptr) {
751  if (ValOrErr)
752    return *ValOrErr;
753  else {
754    if (!Msg)
755      Msg = "Failure value returned from cantFail wrapped call";
756    llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 756);
757  }
758}
759 
760/// Helper for testing applicability of, and applying, handlers for
761/// ErrorInfo types.
762template <typename HandlerT>
763class ErrorHandlerTraits
764    : public ErrorHandlerTraits<decltype(
765          &std::remove_reference<HandlerT>::type::operator())> {};
766 
767// Specialization functions of the form 'Error (const ErrT&)'.
768template <typename ErrT> class ErrorHandlerTraits<Error (&)(ErrT &)> {
769public:
770  static bool appliesTo(const ErrorInfoBase &E) {
771    return E.template isA<ErrT>();
772  }
773 
774  template <typename HandlerT>
775  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
776    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 776, __PRETTY_FUNCTION__));
777    return H(static_cast<ErrT &>(*E));
778  }
779};
780 
781// Specialization functions of the form 'void (const ErrT&)'.
782template <typename ErrT> class ErrorHandlerTraits<void (&)(ErrT &)> {
783public:
784  static bool appliesTo(const ErrorInfoBase &E) {
785    return E.template isA<ErrT>();
786  }
787 
788  template <typename HandlerT>
789  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
790    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 790, __PRETTY_FUNCTION__));
791    H(static_cast<ErrT &>(*E));
792    return Error::success();
793  }
794};
795 
796/// Specialization for functions of the form 'Error (std::unique_ptr<ErrT>)'.
797template <typename ErrT>
798class ErrorHandlerTraits<Error (&)(std::unique_ptr<ErrT>)> {
799public:
800  static bool appliesTo(const ErrorInfoBase &E) {
801    return E.template isA<ErrT>();
802  }
803 
804  template <typename HandlerT>
805  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
806    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 806, __PRETTY_FUNCTION__));
807    std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
808    return H(std::move(SubE));
809  }
810};
811 
812/// Specialization for functions of the form 'void (std::unique_ptr<ErrT>)'.
813template <typename ErrT>
814class ErrorHandlerTraits<void (&)(std::unique_ptr<ErrT>)> {
815public:
816  static bool appliesTo(const ErrorInfoBase &E) {
817    return E.template isA<ErrT>();
818  }
819 
820  template <typename HandlerT>
821  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
822    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 822, __PRETTY_FUNCTION__));
823    std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
824    H(std::move(SubE));
825    return Error::success();
826  }
827};
828 
829// Specialization for member functions of the form 'RetT (const ErrT&)'.
830template <typename C, typename RetT, typename ErrT>
831class ErrorHandlerTraits<RetT (C::*)(ErrT &)>
832    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
833 
834// Specialization for member functions of the form 'RetT (const ErrT&) const'.
835template <typename C, typename RetT, typename ErrT>
836class ErrorHandlerTraits<RetT (C::*)(ErrT &) const>
837    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
838 
839// Specialization for member functions of the form 'RetT (const ErrT&)'.
840template <typename C, typename RetT, typename ErrT>
841class ErrorHandlerTraits<RetT (C::*)(const ErrT &)>
842    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
843 
844// Specialization for member functions of the form 'RetT (const ErrT&) const'.
845template <typename C, typename RetT, typename ErrT>
846class ErrorHandlerTraits<RetT (C::*)(const ErrT &) const>
847    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
848 
849/// Specialization for member functions of the form
850/// 'RetT (std::unique_ptr<ErrT>)'.
851template <typename C, typename RetT, typename ErrT>
852class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>)>
853    : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
854 
855/// Specialization for member functions of the form
856/// 'RetT (std::unique_ptr<ErrT>) const'.
857template <typename C, typename RetT, typename ErrT>
858class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>) const>
859    : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
860 
861inline Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload) {
862  return Error(std::move(Payload));
863}
864 
865template <typename HandlerT, typename... HandlerTs>
866Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload,
867                      HandlerT &&Handler, HandlerTs &&... Handlers) {
868  if (ErrorHandlerTraits<HandlerT>::appliesTo(*Payload))
869    return ErrorHandlerTraits<HandlerT>::apply(std::forward<HandlerT>(Handler),
870                                               std::move(Payload));
871  return handleErrorImpl(std::move(Payload),
872                         std::forward<HandlerTs>(Handlers)...);
873}
874 
875/// Pass the ErrorInfo(s) contained in E to their respective handlers. Any
876/// unhandled errors (or Errors returned by handlers) are re-concatenated and
877/// returned.
878/// Because this function returns an error, its result must also be checked
879/// or returned. If you intend to handle all errors use handleAllErrors
880/// (which returns void, and will abort() on unhandled errors) instead.
881template <typename... HandlerTs>
882Error handleErrors(Error E, HandlerTs &&... Hs) {
883  if (!E)
884    return Error::success();
885 
886  std::unique_ptr<ErrorInfoBase> Payload = E.takePayload();
887 
888  if (Payload->isA<ErrorList>()) {
889    ErrorList &List = static_cast<ErrorList &>(*Payload);
890    Error R;
891    for (auto &P : List.Payloads)
892      R = ErrorList::join(
893          std::move(R),
894          handleErrorImpl(std::move(P), std::forward<HandlerTs>(Hs)...));
895    return R;
896  }
897 
898  return handleErrorImpl(std::move(Payload), std::forward<HandlerTs>(Hs)...);
899}
900 
901/// Behaves the same as handleErrors, except that by contract all errors
902/// *must* be handled by the given handlers (i.e. there must be no remaining
903/// errors after running the handlers, or llvm_unreachable is called).
904template <typename... HandlerTs>
905void handleAllErrors(Error E, HandlerTs &&... Handlers) {
906  cantFail(handleErrors(std::move(E), std::forward<HandlerTs>(Handlers)...));
907}
908 
909/// Check that E is a non-error, then drop it.
910/// If E is an error, llvm_unreachable will be called.
911inline void handleAllErrors(Error E) {
912  cantFail(std::move(E));
913}
914 
915/// Handle any errors (if present) in an Expected<T>, then try a recovery path.
916///
917/// If the incoming value is a success value it is returned unmodified. If it
918/// is a failure value then it the contained error is passed to handleErrors.
919/// If handleErrors is able to handle the error then the RecoveryPath functor
920/// is called to supply the final result. If handleErrors is not able to
921/// handle all errors then the unhandled errors are returned.
922///
923/// This utility enables the follow pattern:
924///
925///   @code{.cpp}
926///   enum FooStrategy { Aggressive, Conservative };
927///   Expected<Foo> foo(FooStrategy S);
928///
929///   auto ResultOrErr =
930///     handleExpected(
931///       foo(Aggressive),
932///       []() { return foo(Conservative); },
933///       [](AggressiveStrategyError&) {
934///         // Implicitly conusme this - we'll recover by using a conservative
935///         // strategy.
936///       });
937///
938///   @endcode
939template <typename T, typename RecoveryFtor, typename... HandlerTs>
940Expected<T> handleExpected(Expected<T> ValOrErr, RecoveryFtor &&RecoveryPath,
941                           HandlerTs &&... Handlers) {
942  if (ValOrErr)
943    return ValOrErr;
944 
945  if (auto Err = handleErrors(ValOrErr.takeError(),
946                              std::forward<HandlerTs>(Handlers)...))
947    return std::move(Err);
948 
949  return RecoveryPath();
950}
951 
952/// Log all errors (if any) in E to OS. If there are any errors, ErrorBanner
953/// will be printed before the first one is logged. A newline will be printed
954/// after each error.
955///
956/// This is useful in the base level of your program to allow clean termination
957/// (allowing clean deallocation of resources, etc.), while reporting error
958/// information to the user.
959void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner);
960 
961/// Write all error messages (if any) in E to a string. The newline character
962/// is used to separate error messages.
963inline std::string toString(Error E) {
964  SmallVector<std::string, 2> Errors;
965  handleAllErrors(std::move(E), [&Errors](const ErrorInfoBase &EI) {
966    Errors.push_back(EI.message());
967  });
968  return join(Errors.begin(), Errors.end(), "\n");
969}
970 
971/// Consume a Error without doing anything. This method should be used
972/// only where an error can be considered a reasonable and expected return
973/// value.
974///
975/// Uses of this method are potentially indicative of design problems: If it's
976/// legitimate to do nothing while processing an "error", the error-producer
977/// might be more clearly refactored to return an Optional<T>.
978inline void consumeError(Error Err) {
979  handleAllErrors(std::move(Err), [](const ErrorInfoBase &) {});
980}
981 
982/// Helper for converting an Error to a bool.
983///
984/// This method returns true if Err is in an error state, or false if it is
985/// in a success state.  Puts Err in a checked state in both cases (unlike
986/// Error::operator bool(), which only does this for success states).
987inline bool errorToBool(Error Err) {
988  bool IsError = static_cast<bool>(Err);
989  if (IsError)
990    consumeError(std::move(Err));
991  return IsError;
992}
993 
994/// Helper for Errors used as out-parameters.
995///
996/// This helper is for use with the Error-as-out-parameter idiom, where an error
997/// is passed to a function or method by reference, rather than being returned.
998/// In such cases it is helpful to set the checked bit on entry to the function
999/// so that the error can be written to (unchecked Errors abort on assignment)
1000/// and clear the checked bit on exit so that clients cannot accidentally forget
1001/// to check the result. This helper performs these actions automatically using
1002/// RAII:
1003///
1004///   @code{.cpp}
1005///   Result foo(Error &Err) {
1006///     ErrorAsOutParameter ErrAsOutParam(&Err); // 'Checked' flag set
1007///     // <body of foo>
1008///     // <- 'Checked' flag auto-cleared when ErrAsOutParam is destructed.
1009///   }
1010///   @endcode
1011///
1012/// ErrorAsOutParameter takes an Error* rather than Error& so that it can be
1013/// used with optional Errors (Error pointers that are allowed to be null). If
1014/// ErrorAsOutParameter took an Error reference, an instance would have to be
1015/// created inside every condition that verified that Error was non-null. By
1016/// taking an Error pointer we can just create one instance at the top of the
1017/// function.
1018class ErrorAsOutParameter {
1019public:
1020  ErrorAsOutParameter(Error *Err) : Err(Err) {
1021    // Raise the checked bit if Err is success.
1022    if (Err)
1023      (void)!!*Err;
1024  }
1025 
1026  ~ErrorAsOutParameter() {
1027    // Clear the checked bit.
1028    if (Err && !*Err)
1029      *Err = Error::success();
1030  }
1031 
1032private:
1033  Error *Err;
1034};
1035 
1036/// Helper for Expected<T>s used as out-parameters.
1037///
1038/// See ErrorAsOutParameter.
1039template <typename T>
1040class ExpectedAsOutParameter {
1041public:
1042  ExpectedAsOutParameter(Expected<T> *ValOrErr)
1043    : ValOrErr(ValOrErr) {
1044    if (ValOrErr)
1045      (void)!!*ValOrErr;
1046  }
1047 
1048  ~ExpectedAsOutParameter() {
1049    if (ValOrErr)
1050      ValOrErr->setUnchecked();
1051  }
1052 
1053private:
1054  Expected<T> *ValOrErr;
1055};
1056 
1057/// This class wraps a std::error_code in a Error.
1058///
1059/// This is useful if you're writing an interface that returns a Error
1060/// (or Expected) and you want to call code that still returns
1061/// std::error_codes.
1062class ECError : public ErrorInfo<ECError> {
1063  friend Error errorCodeToError(std::error_code);
1064 
1065public:
1066  void setErrorCode(std::error_code EC) { this->EC = EC; }
1067  std::error_code convertToErrorCode() const override { return EC; }
1068  void log(raw_ostream &OS) const override { OS << EC.message(); }
1069 
1070  // Used by ErrorInfo::classID.
1071  static char ID;
1072 
1073protected:
1074  ECError() = default;
1075  ECError(std::error_code EC) : EC(EC) {}
1076 
1077  std::error_code EC;
1078};
1079 
1080/// The value returned by this function can be returned from convertToErrorCode
1081/// for Error values where no sensible translation to std::error_code exists.
1082/// It should only be used in this situation, and should never be used where a
1083/// sensible conversion to std::error_code is available, as attempts to convert
1084/// to/from this error will result in a fatal error. (i.e. it is a programmatic
1085///error to try to convert such a value).
1086std::error_code inconvertibleErrorCode();
1087 
1088/// Helper for converting an std::error_code to a Error.
1089Error errorCodeToError(std::error_code EC);
1090 
1091/// Helper for converting an ECError to a std::error_code.
1092///
1093/// This method requires that Err be Error() or an ECError, otherwise it
1094/// will trigger a call to abort().
1095std::error_code errorToErrorCode(Error Err);
1096 
1097/// Convert an ErrorOr<T> to an Expected<T>.
1098template <typename T> Expected<T> errorOrToExpected(ErrorOr<T> &&EO) {
1099  if (auto EC = EO.getError())
1100    return errorCodeToError(EC);
1101  return std::move(*EO);
1102}
1103 
1104/// Convert an Expected<T> to an ErrorOr<T>.
1105template <typename T> ErrorOr<T> expectedToErrorOr(Expected<T> &&E) {
1106  if (auto Err = E.takeError())
1107    return errorToErrorCode(std::move(Err));
1108  return std::move(*E);
1109}
1110 
1111/// This class wraps a string in an Error.
1112///
1113/// StringError is useful in cases where the client is not expected to be able
1114/// to consume the specific error message programmatically (for example, if the
1115/// error message is to be presented to the user).
1116///
1117/// StringError can also be used when additional information is to be printed
1118/// along with a error_code message. Depending on the constructor called, this
1119/// class can either display:
1120///    1. the error_code message (ECError behavior)
1121///    2. a string
1122///    3. the error_code message and a string
1123///
1124/// These behaviors are useful when subtyping is required; for example, when a
1125/// specific library needs an explicit error type. In the example below,
1126/// PDBError is derived from StringError:
1127///
1128///   @code{.cpp}
1129///   Expected<int> foo() {
1130///      return llvm::make_error<PDBError>(pdb_error_code::dia_failed_loading,
1131///                                        "Additional information");
1132///   }
1133///   @endcode
1134///
1135class StringError : public ErrorInfo<StringError> {
1136public:
1137  static char ID;
1138 
1139  // Prints EC + S and converts to EC
1140  StringError(std::error_code EC, const Twine &S = Twine());
1141 
1142  // Prints S and converts to EC
1143  StringError(const Twine &S, std::error_code EC);
1144 
1145  void log(raw_ostream &OS) const override;
1146  std::error_code convertToErrorCode() const override;
1147 
1148  const std::string &getMessage() const { return Msg; }
1149 
1150private:
1151  std::string Msg;
1152  std::error_code EC;
1153  const bool PrintMsgOnly = false;
1154};
1155 
1156/// Create formatted StringError object.
1157template <typename... Ts>
1158Error createStringError(std::error_code EC, char const *Fmt,
1159                        const Ts &... Vals) {
1160  std::string Buffer;
1161  raw_string_ostream Stream(Buffer);
1162  Stream << format(Fmt, Vals...);
1163  return make_error<StringError>(Stream.str(), EC);
1164}
1165 
1166Error createStringError(std::error_code EC, char const *Msg);
1167 
1168/// This class wraps a filename and another Error.
1169///
1170/// In some cases, an error needs to live along a 'source' name, in order to
1171/// show more detailed information to the user.
1172class FileError final : public ErrorInfo<FileError> {
1173 
1174  friend Error createFileError(std::string, Error);
1175 
1176public:
1177  void log(raw_ostream &OS) const override {
1178    assert(Err && !FileName.empty() && "Trying to log after takeError().")((Err && !FileName.empty() && "Trying to log after takeError()."
) ? static_cast<void> (0) : __assert_fail ("Err && !FileName.empty() && \"Trying to log after takeError().\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 1178, __PRETTY_FUNCTION__));
1179    OS << "'" << FileName << "': ";
1180    Err->log(OS);
1181  }
1182 
1183  Error takeError() { return Error(std::move(Err)); }
1184 
1185  std::error_code convertToErrorCode() const override;
1186 
1187  // Used by ErrorInfo::classID.
1188  static char ID;
1189 
1190private:
1191  FileError(std::string F, std::unique_ptr<ErrorInfoBase> E) {
1192    assert(E && "Cannot create FileError from Error success value.")((E && "Cannot create FileError from Error success value."
) ? static_cast<void> (0) : __assert_fail ("E && \"Cannot create FileError from Error success value.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 1192, __PRETTY_FUNCTION__));
1193    assert(!F.empty() &&((!F.empty() && "The file name provided to FileError must not be empty."
) ? static_cast<void> (0) : __assert_fail ("!F.empty() && \"The file name provided to FileError must not be empty.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 1194, __PRETTY_FUNCTION__))
1194           "The file name provided to FileError must not be empty.")((!F.empty() && "The file name provided to FileError must not be empty."
) ? static_cast<void> (0) : __assert_fail ("!F.empty() && \"The file name provided to FileError must not be empty.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/Support/Error.h"
, 1194, __PRETTY_FUNCTION__));
1195    FileName = F;
1196    Err = std::move(E);
1197  }
1198 
1199  static Error build(std::string F, Error E) {
1200    return Error(std::unique_ptr<FileError>(new FileError(F, E.takePayload())));
1201  }
1202 
1203  std::string FileName;
1204  std::unique_ptr<ErrorInfoBase> Err;
1205};
1206 
1207/// Concatenate a source file path and/or name with an Error. The resulting
1208/// Error is unchecked.
1209inline Error createFileError(std::string F, Error E) {
1210  return FileError::build(F, std::move(E));
1211}
1212 
1213Error createFileError(std::string F, ErrorSuccess) = delete;
1214 
1215/// Helper for check-and-exit error handling.
1216///
1217/// For tool use only. NOT FOR USE IN LIBRARY CODE.
1218///
1219class ExitOnError {
1220public:
1221  /// Create an error on exit helper.
1222  ExitOnError(std::string Banner = "", int DefaultErrorExitCode = 1)
1223      : Banner(std::move(Banner)),
1224        GetExitCode([=](const Error &) { return DefaultErrorExitCode; }) {}
1225 
1226  /// Set the banner string for any errors caught by operator().
1227  void setBanner(std::string Banner) { this->Banner = std::move(Banner); }
1228 
1229  /// Set the exit-code mapper function.
1230  void setExitCodeMapper(std::function<int(const Error &)> GetExitCode) {
1231    this->GetExitCode = std::move(GetExitCode);
1232  }
1233 
1234  /// Check Err. If it's in a failure state log the error(s) and exit.
1235  void operator()(Error Err) const { checkError(std::move(Err)); }
1236 
1237  /// Check E. If it's in a success state then return the contained value. If
1238  /// it's in a failure state log the error(s) and exit.
1239  template <typename T> T operator()(Expected<T> &&E) const {
1240    checkError(E.takeError());
1241    return std::move(*E);
1242  }
1243 
1244  /// Check E. If it's in a success state then return the contained reference. If
1245  /// it's in a failure state log the error(s) and exit.
1246  template <typename T> T& operator()(Expected<T&> &&E) const {
1247    checkError(E.takeError());
1248    return *E;
1249  }
1250 
1251private:
1252  void checkError(Error Err) const {
1253    if (Err) {
1254      int ExitCode = GetExitCode(Err);
1255      logAllUnhandledErrors(std::move(Err), errs(), Banner);
1256      exit(ExitCode);
1257    }
1258  }
1259 
1260  std::string Banner;
1261  std::function<int(const Error &)> GetExitCode;
1262};
1263 
1264/// Conversion from Error to LLVMErrorRef for C error bindings.
1265inline LLVMErrorRef wrap(Error Err) {
1266  return reinterpret_cast<LLVMErrorRef>(Err.takePayload().release());
1267}
1268 
1269/// Conversion from LLVMErrorRef to Error for C error bindings.
1270inline Error unwrap(LLVMErrorRef ErrRef) {
1271  return Error(std::unique_ptr<ErrorInfoBase>(
1272      reinterpret_cast<ErrorInfoBase *>(ErrRef)));
1273}
1274 
1275} // end namespace llvm
1276 
1277#endif // LLVM_SUPPORT_ERROR_H

←

/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/ADT/STLExtras.h

1//===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains some templates that are useful if you are working with the
11// STL at all.
12//
13// No library is required when using these functions.
14//
15//===----------------------------------------------------------------------===//
16 
17#ifndef LLVM_ADT_STLEXTRAS_H
18#define LLVM_ADT_STLEXTRAS_H
19 
20#include "llvm/ADT/Optional.h"
21#include "llvm/ADT/SmallVector.h"
22#include "llvm/ADT/iterator.h"
23#include "llvm/ADT/iterator_range.h"
24#include "llvm/Config/abi-breaking.h"
25#include "llvm/Support/ErrorHandling.h"
26#include <algorithm>
27#include <cassert>
28#include <cstddef>
29#include <cstdint>
30#include <cstdlib>
31#include <functional>
32#include <initializer_list>
33#include <iterator>
34#include <limits>
35#include <memory>
36#include <tuple>
37#include <type_traits>
38#include <utility>
39 
40#ifdef EXPENSIVE_CHECKS
41#include <random> // for std::mt19937
42#endif
43 
44namespace llvm {
45 
46// Only used by compiler if both template types are the same.  Useful when
47// using SFINAE to test for the existence of member functions.
48template <typename T, T> struct SameType;
49 
50namespace detail {
51 
52template <typename RangeT>
53using IterOfRange = decltype(std::begin(std::declval<RangeT &>()));
54 
55template <typename RangeT>
56using ValueOfRange = typename std::remove_reference<decltype(
57    *std::begin(std::declval<RangeT &>()))>::type;
58 
59} // end namespace detail
60 
61//===----------------------------------------------------------------------===//
62//     Extra additions to <type_traits>
63//===----------------------------------------------------------------------===//
64 
65template <typename T>
66struct negation : std::integral_constant<bool, !bool(T::value)> {};
67 
68template <typename...> struct conjunction : std::true_type {};
69template <typename B1> struct conjunction<B1> : B1 {};
70template <typename B1, typename... Bn>
71struct conjunction<B1, Bn...>
72    : std::conditional<bool(B1::value), conjunction<Bn...>, B1>::type {};
73 
74//===----------------------------------------------------------------------===//
75//     Extra additions to <functional>
76//===----------------------------------------------------------------------===//
77 
78template <class Ty> struct identity {
79  using argument_type = Ty;
80 
81  Ty &operator()(Ty &self) const {
82    return self;
83  }
84  const Ty &operator()(const Ty &self) const {
85    return self;
86  }
87};
88 
89template <class Ty> struct less_ptr {
90  bool operator()(const Ty* left, const Ty* right) const {
91    return *left < *right;
92  }
93};
94 
95template <class Ty> struct greater_ptr {
96  bool operator()(const Ty* left, const Ty* right) const {
97    return *right < *left;
98  }
99};
100 
101/// An efficient, type-erasing, non-owning reference to a callable. This is
102/// intended for use as the type of a function parameter that is not used
103/// after the function in question returns.
104///
105/// This class does not own the callable, so it is not in general safe to store
106/// a function_ref.
107template<typename Fn> class function_ref;
108 
109template<typename Ret, typename ...Params>
110class function_ref<Ret(Params...)> {
111  Ret (*callback)(intptr_t callable, Params ...params) = nullptr;
112  intptr_t callable;
113 
114  template<typename Callable>
115  static Ret callback_fn(intptr_t callable, Params ...params) {
116    return (*reinterpret_cast<Callable*>(callable))(
117        std::forward<Params>(params)...);
118  }
119 
120public:
121  function_ref() = default;
122  function_ref(std::nullptr_t) {}
123 
124  template <typename Callable>
125  function_ref(Callable &&callable,
126               typename std::enable_if<
127                   !std::is_same<typename std::remove_reference<Callable>::type,
128                                 function_ref>::value>::type * = nullptr)
129      : callback(callback_fn<typename std::remove_reference<Callable>::type>),
130        callable(reinterpret_cast<intptr_t>(&callable)) {}
131 
132  Ret operator()(Params ...params) const {
133    return callback(callable, std::forward<Params>(params)...);
134  }
135 
136  operator bool() const { return callback; }
137};
138 
139// deleter - Very very very simple method that is used to invoke operator
140// delete on something.  It is used like this:
141//
142//   for_each(V.begin(), B.end(), deleter<Interval>);
143template <class T>
144inline void deleter(T *Ptr) {
145  delete Ptr;
146}
147 
148//===----------------------------------------------------------------------===//
149//     Extra additions to <iterator>
150//===----------------------------------------------------------------------===//
151 
152namespace adl_detail {
153 
154using std::begin;
155 
156template <typename ContainerTy>
157auto adl_begin(ContainerTy &&container)
158    -> decltype(begin(std::forward<ContainerTy>(container))) {
159  return begin(std::forward<ContainerTy>(container));
160}
161 
162using std::end;
163 
164template <typename ContainerTy>
165auto adl_end(ContainerTy &&container)
166    -> decltype(end(std::forward<ContainerTy>(container))) {
167  return end(std::forward<ContainerTy>(container));
168}
169 
170using std::swap;
171 
172template <typename T>
173void adl_swap(T &&lhs, T &&rhs) noexcept(noexcept(swap(std::declval<T>(),
174                                                       std::declval<T>()))) {
175  swap(std::forward<T>(lhs), std::forward<T>(rhs));
176}
177 
178} // end namespace adl_detail
179 
180template <typename ContainerTy>
181auto adl_begin(ContainerTy &&container)
182    -> decltype(adl_detail::adl_begin(std::forward<ContainerTy>(container))) {
183  return adl_detail::adl_begin(std::forward<ContainerTy>(container));
184}
185 
186template <typename ContainerTy>
187auto adl_end(ContainerTy &&container)
188    -> decltype(adl_detail::adl_end(std::forward<ContainerTy>(container))) {
189  return adl_detail::adl_end(std::forward<ContainerTy>(container));
190}
191 
192template <typename T>
193void adl_swap(T &&lhs, T &&rhs) noexcept(
194    noexcept(adl_detail::adl_swap(std::declval<T>(), std::declval<T>()))) {
195  adl_detail::adl_swap(std::forward<T>(lhs), std::forward<T>(rhs));
196}
197 
198// mapped_iterator - This is a simple iterator adapter that causes a function to
199// be applied whenever operator* is invoked on the iterator.
200 
201template <typename ItTy, typename FuncTy,
202          typename FuncReturnTy =
203            decltype(std::declval<FuncTy>()(*std::declval<ItTy>()))>
204class mapped_iterator
205    : public iterator_adaptor_base<
206             mapped_iterator<ItTy, FuncTy>, ItTy,
207             typename std::iterator_traits<ItTy>::iterator_category,
208             typename std::remove_reference<FuncReturnTy>::type> {
209public:
210  mapped_iterator(ItTy U, FuncTy F)
211    : mapped_iterator::iterator_adaptor_base(std::move(U)), F(std::move(F)) {}
212 
213  ItTy getCurrent() { return this->I; }
214 
215  FuncReturnTy operator*() { return F(*this->I); }
216 
217private:
218  FuncTy F;
219};
220 
221// map_iterator - Provide a convenient way to create mapped_iterators, just like
222// make_pair is useful for creating pairs...
223template <class ItTy, class FuncTy>
224inline mapped_iterator<ItTy, FuncTy> map_iterator(ItTy I, FuncTy F) {
225  return mapped_iterator<ItTy, FuncTy>(std::move(I), std::move(F));
226}
227 
228/// Helper to determine if type T has a member called rbegin().
229template <typename Ty> class has_rbegin_impl {
230  using yes = char[1];
231  using no = char[2];
232 
233  template <typename Inner>
234  static yes& test(Inner *I, decltype(I->rbegin()) * = nullptr);
235 
236  template <typename>
237  static no& test(...);
238 
239public:
240  static const bool value = sizeof(test<Ty>(nullptr)) == sizeof(yes);
241};
242 
243/// Metafunction to determine if T& or T has a member called rbegin().
244template <typename Ty>
245struct has_rbegin : has_rbegin_impl<typename std::remove_reference<Ty>::type> {
246};
247 
248// Returns an iterator_range over the given container which iterates in reverse.
249// Note that the container must have rbegin()/rend() methods for this to work.
250template <typename ContainerTy>
251auto reverse(ContainerTy &&C,
252             typename std::enable_if<has_rbegin<ContainerTy>::value>::type * =
253                 nullptr) -> decltype(make_range(C.rbegin(), C.rend())) {
254  return make_range(C.rbegin(), C.rend());
255}
256 
257// Returns a std::reverse_iterator wrapped around the given iterator.
258template <typename IteratorTy>
259std::reverse_iterator<IteratorTy> make_reverse_iterator(IteratorTy It) {
260  return std::reverse_iterator<IteratorTy>(It);
261}
262 
263// Returns an iterator_range over the given container which iterates in reverse.
264// Note that the container must have begin()/end() methods which return
265// bidirectional iterators for this to work.
266template <typename ContainerTy>
267auto reverse(
268    ContainerTy &&C,
269    typename std::enable_if<!has_rbegin<ContainerTy>::value>::type * = nullptr)
270    -> decltype(make_range(llvm::make_reverse_iterator(std::end(C)),
271                           llvm::make_reverse_iterator(std::begin(C)))) {
272  return make_range(llvm::make_reverse_iterator(std::end(C)),
273                    llvm::make_reverse_iterator(std::begin(C)));
274}
275 
276/// An iterator adaptor that filters the elements of given inner iterators.
277///
278/// The predicate parameter should be a callable object that accepts the wrapped
279/// iterator's reference type and returns a bool. When incrementing or
280/// decrementing the iterator, it will call the predicate on each element and
281/// skip any where it returns false.
282///
283/// \code
284///   int A[] = { 1, 2, 3, 4 };
285///   auto R = make_filter_range(A, [](int N) { return N % 2 == 1; });
286///   // R contains { 1, 3 }.
287/// \endcode
288///
289/// Note: filter_iterator_base implements support for forward iteration.
290/// filter_iterator_impl exists to provide support for bidirectional iteration,
291/// conditional on whether the wrapped iterator supports it.
292template <typename WrappedIteratorT, typename PredicateT, typename IterTag>
293class filter_iterator_base
294    : public iterator_adaptor_base<
295          filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>,
296          WrappedIteratorT,
297          typename std::common_type<
298              IterTag, typename std::iterator_traits<
299                           WrappedIteratorT>::iterator_category>::type> {
300  using BaseT = iterator_adaptor_base<
301      filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>,
302      WrappedIteratorT,
303      typename std::common_type<
304          IterTag, typename std::iterator_traits<
305                       WrappedIteratorT>::iterator_category>::type>;
306 
307protected:
308  WrappedIteratorT End;
309  PredicateT Pred;
310 
311  void findNextValid() {
312    while (this->I != End && !Pred(*this->I))
313      BaseT::operator++();
314  }
315 
316  // Construct the iterator. The begin iterator needs to know where the end
317  // is, so that it can properly stop when it gets there. The end iterator only
318  // needs the predicate to support bidirectional iteration.
319  filter_iterator_base(WrappedIteratorT Begin, WrappedIteratorT End,
320                       PredicateT Pred)
321      : BaseT(Begin), End(End), Pred(Pred) {
322    findNextValid();
323  }
324 
325public:
326  using BaseT::operator++;
327 
328  filter_iterator_base &operator++() {
329    BaseT::operator++();
330    findNextValid();
331    return *this;
332  }
333};
334 
335/// Specialization of filter_iterator_base for forward iteration only.
336template <typename WrappedIteratorT, typename PredicateT,
337          typename IterTag = std::forward_iterator_tag>
338class filter_iterator_impl
339    : public filter_iterator_base<WrappedIteratorT, PredicateT, IterTag> {
340  using BaseT = filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>;
341 
342public:
343  filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End,
344                       PredicateT Pred)
345      : BaseT(Begin, End, Pred) {}
346};
347 
348/// Specialization of filter_iterator_base for bidirectional iteration.
349template <typename WrappedIteratorT, typename PredicateT>
350class filter_iterator_impl<WrappedIteratorT, PredicateT,
351                           std::bidirectional_iterator_tag>
352    : public filter_iterator_base<WrappedIteratorT, PredicateT,
353                                  std::bidirectional_iterator_tag> {
354  using BaseT = filter_iterator_base<WrappedIteratorT, PredicateT,
355                                     std::bidirectional_iterator_tag>;
356  void findPrevValid() {
357    while (!this->Pred(*this->I))
358      BaseT::operator--();
359  }
360 
361public:
362  using BaseT::operator--;
363 
364  filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End,
365                       PredicateT Pred)
366      : BaseT(Begin, End, Pred) {}
367 
368  filter_iterator_impl &operator--() {
369    BaseT::operator--();
370    findPrevValid();
371    return *this;
372  }
373};
374 
375namespace detail {
376 
377template <bool is_bidirectional> struct fwd_or_bidi_tag_impl {
378  using type = std::forward_iterator_tag;
379};
380 
381template <> struct fwd_or_bidi_tag_impl<true> {
382  using type = std::bidirectional_iterator_tag;
383};
384 
385/// Helper which sets its type member to forward_iterator_tag if the category
386/// of \p IterT does not derive from bidirectional_iterator_tag, and to
387/// bidirectional_iterator_tag otherwise.
388template <typename IterT> struct fwd_or_bidi_tag {
389  using type = typename fwd_or_bidi_tag_impl<std::is_base_of<
390      std::bidirectional_iterator_tag,
391      typename std::iterator_traits<IterT>::iterator_category>::value>::type;
392};
393 
394} // namespace detail
395 
396/// Defines filter_iterator to a suitable specialization of
397/// filter_iterator_impl, based on the underlying iterator's category.
398template <typename WrappedIteratorT, typename PredicateT>
399using filter_iterator = filter_iterator_impl<
400    WrappedIteratorT, PredicateT,
401    typename detail::fwd_or_bidi_tag<WrappedIteratorT>::type>;
402 
403/// Convenience function that takes a range of elements and a predicate,
404/// and return a new filter_iterator range.
405///
406/// FIXME: Currently if RangeT && is a rvalue reference to a temporary, the
407/// lifetime of that temporary is not kept by the returned range object, and the
408/// temporary is going to be dropped on the floor after the make_iterator_range
409/// full expression that contains this function call.
410template <typename RangeT, typename PredicateT>
411iterator_range<filter_iterator<detail::IterOfRange<RangeT>, PredicateT>>
412make_filter_range(RangeT &&Range, PredicateT Pred) {
413  using FilterIteratorT =
414      filter_iterator<detail::IterOfRange<RangeT>, PredicateT>;
415  return make_range(
416      FilterIteratorT(std::begin(std::forward<RangeT>(Range)),
417                      std::end(std::forward<RangeT>(Range)), Pred),
418      FilterIteratorT(std::end(std::forward<RangeT>(Range)),
419                      std::end(std::forward<RangeT>(Range)), Pred));
420}
421 
422/// A pseudo-iterator adaptor that is designed to implement "early increment"
423/// style loops.
424///
425/// This is *not a normal iterator* and should almost never be used directly. It
426/// is intended primarily to be used with range based for loops and some range
427/// algorithms.
428///
429/// The iterator isn't quite an `OutputIterator` or an `InputIterator` but
430/// somewhere between them. The constraints of these iterators are:
431///
432/// - On construction or after being incremented, it is comparable and
433///   dereferencable. It is *not* incrementable.
434/// - After being dereferenced, it is neither comparable nor dereferencable, it
435///   is only incrementable.
436///
437/// This means you can only dereference the iterator once, and you can only
438/// increment it once between dereferences.
439template <typename WrappedIteratorT>
440class early_inc_iterator_impl
441    : public iterator_adaptor_base<early_inc_iterator_impl<WrappedIteratorT>,
442                                   WrappedIteratorT, std::input_iterator_tag> {
443  using BaseT =
444      iterator_adaptor_base<early_inc_iterator_impl<WrappedIteratorT>,
445                            WrappedIteratorT, std::input_iterator_tag>;
446 
447  using PointerT = typename std::iterator_traits<WrappedIteratorT>::pointer;
448 
449protected:
450#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
451  bool IsEarlyIncremented = false;
452#endif
453 
454public:
455  early_inc_iterator_impl(WrappedIteratorT I) : BaseT(I) {}
456 
457  using BaseT::operator*;
458  typename BaseT::reference operator*() {
459#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
460    assert(!IsEarlyIncremented && "Cannot dereference twice!")((!IsEarlyIncremented && "Cannot dereference twice!")
 ? static_cast<void> (0) : __assert_fail ("!IsEarlyIncremented && \"Cannot dereference twice!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/ADT/STLExtras.h"
, 460, __PRETTY_FUNCTION__));
461    IsEarlyIncremented = true;
462#endif
463    return *(this->I)++;
464  }
465 
466  using BaseT::operator++;
467  early_inc_iterator_impl &operator++() {
468#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
469    assert(IsEarlyIncremented && "Cannot increment before dereferencing!")((IsEarlyIncremented && "Cannot increment before dereferencing!"
) ? static_cast<void> (0) : __assert_fail ("IsEarlyIncremented && \"Cannot increment before dereferencing!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/ADT/STLExtras.h"
, 469, __PRETTY_FUNCTION__));
470    IsEarlyIncremented = false;
471#endif
472    return *this;
473  }
474 
475  using BaseT::operator==;
476  bool operator==(const early_inc_iterator_impl &RHS) const {
477#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
478    assert(!IsEarlyIncremented && "Cannot compare after dereferencing!")((!IsEarlyIncremented && "Cannot compare after dereferencing!"
) ? static_cast<void> (0) : __assert_fail ("!IsEarlyIncremented && \"Cannot compare after dereferencing!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/ADT/STLExtras.h"
, 478, __PRETTY_FUNCTION__));
479#endif
480    return BaseT::operator==(RHS);
481  }
482};
483 
484/// Make a range that does early increment to allow mutation of the underlying
485/// range without disrupting iteration.
486///
487/// The underlying iterator will be incremented immediately after it is
488/// dereferenced, allowing deletion of the current node or insertion of nodes to
489/// not disrupt iteration provided they do not invalidate the *next* iterator --
490/// the current iterator can be invalidated.
491///
492/// This requires a very exact pattern of use that is only really suitable to
493/// range based for loops and other range algorithms that explicitly guarantee
494/// to dereference exactly once each element, and to increment exactly once each
495/// element.
496template <typename RangeT>
497iterator_range<early_inc_iterator_impl<detail::IterOfRange<RangeT>>>
498make_early_inc_range(RangeT &&Range) {
499  using EarlyIncIteratorT =
500      early_inc_iterator_impl<detail::IterOfRange<RangeT>>;
501  return make_range(EarlyIncIteratorT(std::begin(std::forward<RangeT>(Range))),
502                    EarlyIncIteratorT(std::end(std::forward<RangeT>(Range))));
503}
504 
505// forward declarations required by zip_shortest/zip_first
506template <typename R, typename UnaryPredicate>
507bool all_of(R &&range, UnaryPredicate P);
508 
509template <size_t... I> struct index_sequence;
510 
511template <class... Ts> struct index_sequence_for;
512 
513namespace detail {
514 
515using std::declval;
516 
517// We have to alias this since inlining the actual type at the usage site
518// in the parameter list of iterator_facade_base<> below ICEs MSVC 2017.
519template<typename... Iters> struct ZipTupleType {
520  using type = std::tuple<decltype(*declval<Iters>())...>;
521};
522 
523template <typename ZipType, typename... Iters>
524using zip_traits = iterator_facade_base<
525    ZipType, typename std::common_type<std::bidirectional_iterator_tag,
526                                       typename std::iterator_traits<
527                                           Iters>::iterator_category...>::type,
528    // ^ TODO: Implement random access methods.
529    typename ZipTupleType<Iters...>::type,
530    typename std::iterator_traits<typename std::tuple_element<
531        0, std::tuple<Iters...>>::type>::difference_type,
532    // ^ FIXME: This follows boost::make_zip_iterator's assumption that all
533    // inner iterators have the same difference_type. It would fail if, for
534    // instance, the second field's difference_type were non-numeric while the
535    // first is.
536    typename ZipTupleType<Iters...>::type *,
537    typename ZipTupleType<Iters...>::type>;
538 
539template <typename ZipType, typename... Iters>
540struct zip_common : public zip_traits<ZipType, Iters...> {
541  using Base = zip_traits<ZipType, Iters...>;
542  using value_type = typename Base::value_type;
543 
544  std::tuple<Iters...> iterators;
545 
546protected:
547  template <size_t... Ns> value_type deref(index_sequence<Ns...>) const {
548    return value_type(*std::get<Ns>(iterators)...);
549  }
550 
551  template <size_t... Ns>
552  decltype(iterators) tup_inc(index_sequence<Ns...>) const {
553    return std::tuple<Iters...>(std::next(std::get<Ns>(iterators))...);
554  }
555 
556  template <size_t... Ns>
557  decltype(iterators) tup_dec(index_sequence<Ns...>) const {
558    return std::tuple<Iters...>(std::prev(std::get<Ns>(iterators))...);
559  }
560 
561public:
562  zip_common(Iters &&... ts) : iterators(std::forward<Iters>(ts)...) {}
563 
564  value_type operator*() { return deref(index_sequence_for<Iters...>{}); }
565 
566  const value_type operator*() const {
567    return deref(index_sequence_for<Iters...>{});
568  }
569 
570  ZipType &operator++() {
571    iterators = tup_inc(index_sequence_for<Iters...>{});
572    return *reinterpret_cast<ZipType *>(this);
573  }
574 
575  ZipType &operator--() {
576    static_assert(Base::IsBidirectional,
577                  "All inner iterators must be at least bidirectional.");
578    iterators = tup_dec(index_sequence_for<Iters...>{});
579    return *reinterpret_cast<ZipType *>(this);
580  }
581};
582 
583template <typename... Iters>
584struct zip_first : public zip_common<zip_first<Iters...>, Iters...> {
585  using Base = zip_common<zip_first<Iters...>, Iters...>;
586 
587  bool operator==(const zip_first<Iters...> &other) const {
588    return std::get<0>(this->iterators) == std::get<0>(other.iterators);
589  }
590 
591  zip_first(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {}
592};
593 
594template <typename... Iters>
595class zip_shortest : public zip_common<zip_shortest<Iters...>, Iters...> {
596  template <size_t... Ns>
597  bool test(const zip_shortest<Iters...> &other, index_sequence<Ns...>) const {
598    return all_of(std::initializer_list<bool>{std::get<Ns>(this->iterators) !=
599                                              std::get<Ns>(other.iterators)...},
600                  identity<bool>{});
601  }
602 
603public:
604  using Base = zip_common<zip_shortest<Iters...>, Iters...>;
605 
606  zip_shortest(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {}
607 
608  bool operator==(const zip_shortest<Iters...> &other) const {
609    return !test(other, index_sequence_for<Iters...>{});
610  }
611};
612 
613template <template <typename...> class ItType, typename... Args> class zippy {
614public:
615  using iterator = ItType<decltype(std::begin(std::declval<Args>()))...>;
616  using iterator_category = typename iterator::iterator_category;
617  using value_type = typename iterator::value_type;
618  using difference_type = typename iterator::difference_type;
619  using pointer = typename iterator::pointer;
620  using reference = typename iterator::reference;
621 
622private:
623  std::tuple<Args...> ts;
624 
625  template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) const {
626    return iterator(std::begin(std::get<Ns>(ts))...);
627  }
628  template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) const {
629    return iterator(std::end(std::get<Ns>(ts))...);
630  }
631 
632public:
633  zippy(Args &&... ts_) : ts(std::forward<Args>(ts_)...) {}
634 
635  iterator begin() const { return begin_impl(index_sequence_for<Args...>{}); }
636  iterator end() const { return end_impl(index_sequence_for<Args...>{}); }
637};
638 
639} // end namespace detail
640 
641/// zip iterator for two or more iteratable types.
642template <typename T, typename U, typename... Args>
643detail::zippy<detail::zip_shortest, T, U, Args...> zip(T &&t, U &&u,
644                                                       Args &&... args) {
645  return detail::zippy<detail::zip_shortest, T, U, Args...>(
646      std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
647}
648 
649/// zip iterator that, for the sake of efficiency, assumes the first iteratee to
650/// be the shortest.
651template <typename T, typename U, typename... Args>
652detail::zippy<detail::zip_first, T, U, Args...> zip_first(T &&t, U &&u,
653                                                          Args &&... args) {
654  return detail::zippy<detail::zip_first, T, U, Args...>(
655      std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
656}
657 
658/// Iterator wrapper that concatenates sequences together.
659///
660/// This can concatenate different iterators, even with different types, into
661/// a single iterator provided the value types of all the concatenated
662/// iterators expose `reference` and `pointer` types that can be converted to
663/// `ValueT &` and `ValueT *` respectively. It doesn't support more
664/// interesting/customized pointer or reference types.
665///
666/// Currently this only supports forward or higher iterator categories as
667/// inputs and always exposes a forward iterator interface.
668template <typename ValueT, typename... IterTs>
669class concat_iterator
670    : public iterator_facade_base<concat_iterator<ValueT, IterTs...>,
671                                  std::forward_iterator_tag, ValueT> {
672  using BaseT = typename concat_iterator::iterator_facade_base;
673 
674  /// We store both the current and end iterators for each concatenated
675  /// sequence in a tuple of pairs.
676  ///
677  /// Note that something like iterator_range seems nice at first here, but the
678  /// range properties are of little benefit and end up getting in the way
679  /// because we need to do mutation on the current iterators.
680  std::tuple<IterTs...> Begins;
681  std::tuple<IterTs...> Ends;
682 
683  /// Attempts to increment a specific iterator.
684  ///
685  /// Returns true if it was able to increment the iterator. Returns false if
686  /// the iterator is already at the end iterator.
687  template <size_t Index> bool incrementHelper() {
688    auto &Begin = std::get<Index>(Begins);
689    auto &End = std::get<Index>(Ends);
690    if (Begin == End)
691      return false;
692 
693    ++Begin;
694    return true;
695  }
696 
697  /// Increments the first non-end iterator.
698  ///
699  /// It is an error to call this with all iterators at the end.
700  template <size_t... Ns> void increment(index_sequence<Ns...>) {
701    // Build a sequence of functions to increment each iterator if possible.
702    bool (concat_iterator::*IncrementHelperFns[])() = {
703        &concat_iterator::incrementHelper<Ns>...};
704 
705    // Loop over them, and stop as soon as we succeed at incrementing one.
706    for (auto &IncrementHelperFn : IncrementHelperFns)
707      if ((this->*IncrementHelperFn)())
708        return;
709 
710    llvm_unreachable("Attempted to increment an end concat iterator!")::llvm::llvm_unreachable_internal("Attempted to increment an end concat iterator!"
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/ADT/STLExtras.h"
, 710);
711  }
712 
713  /// Returns null if the specified iterator is at the end. Otherwise,
714  /// dereferences the iterator and returns the address of the resulting
715  /// reference.
716  template <size_t Index> ValueT *getHelper() const {
717    auto &Begin = std::get<Index>(Begins);
718    auto &End = std::get<Index>(Ends);
719    if (Begin == End)
720      return nullptr;
721 
722    return &*Begin;
723  }
724 
725  /// Finds the first non-end iterator, dereferences, and returns the resulting
726  /// reference.
727  ///
728  /// It is an error to call this with all iterators at the end.
729  template <size_t... Ns> ValueT &get(index_sequence<Ns...>) const {
730    // Build a sequence of functions to get from iterator if possible.
731    ValueT *(concat_iterator::*GetHelperFns[])() const = {
732        &concat_iterator::getHelper<Ns>...};
733 
734    // Loop over them, and return the first result we find.
735    for (auto &GetHelperFn : GetHelperFns)
736      if (ValueT *P = (this->*GetHelperFn)())
737        return *P;
738 
739    llvm_unreachable("Attempted to get a pointer from an end concat iterator!")::llvm::llvm_unreachable_internal("Attempted to get a pointer from an end concat iterator!"
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/ADT/STLExtras.h"
, 739);
740  }
741 
742public:
743  /// Constructs an iterator from a squence of ranges.
744  ///
745  /// We need the full range to know how to switch between each of the
746  /// iterators.
747  template <typename... RangeTs>
748  explicit concat_iterator(RangeTs &&... Ranges)
749      : Begins(std::begin(Ranges)...), Ends(std::end(Ranges)...) {}
750 
751  using BaseT::operator++;
752 
753  concat_iterator &operator++() {
754    increment(index_sequence_for<IterTs...>());
755    return *this;
756  }
757 
758  ValueT &operator*() const { return get(index_sequence_for<IterTs...>()); }
759 
760  bool operator==(const concat_iterator &RHS) const {
761    return Begins == RHS.Begins && Ends == RHS.Ends;
762  }
763};
764 
765namespace detail {
766 
767/// Helper to store a sequence of ranges being concatenated and access them.
768///
769/// This is designed to facilitate providing actual storage when temporaries
770/// are passed into the constructor such that we can use it as part of range
771/// based for loops.
772template <typename ValueT, typename... RangeTs> class concat_range {
773public:
774  using iterator =
775      concat_iterator<ValueT,
776                      decltype(std::begin(std::declval<RangeTs &>()))...>;
777 
778private:
779  std::tuple<RangeTs...> Ranges;
780 
781  template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) {
782    return iterator(std::get<Ns>(Ranges)...);
783  }
784  template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) {
785    return iterator(make_range(std::end(std::get<Ns>(Ranges)),
786                               std::end(std::get<Ns>(Ranges)))...);
787  }
788 
789public:
790  concat_range(RangeTs &&... Ranges)
791      : Ranges(std::forward<RangeTs>(Ranges)...) {}
792 
793  iterator begin() { return begin_impl(index_sequence_for<RangeTs...>{}); }
794  iterator end() { return end_impl(index_sequence_for<RangeTs...>{}); }
795};
796 
797} // end namespace detail
798 
799/// Concatenated range across two or more ranges.
800///
801/// The desired value type must be explicitly specified.
802template <typename ValueT, typename... RangeTs>
803detail::concat_range<ValueT, RangeTs...> concat(RangeTs &&... Ranges) {
804  static_assert(sizeof...(RangeTs) > 1,
805                "Need more than one range to concatenate!");
806  return detail::concat_range<ValueT, RangeTs...>(
807      std::forward<RangeTs>(Ranges)...);
808}
809 
810//===----------------------------------------------------------------------===//
811//     Extra additions to <utility>
812//===----------------------------------------------------------------------===//
813 
814/// Function object to check whether the first component of a std::pair
815/// compares less than the first component of another std::pair.
816struct less_first {
817  template <typename T> bool operator()(const T &lhs, const T &rhs) const {
818    return lhs.first < rhs.first;
819  }
820};
821 
822/// Function object to check whether the second component of a std::pair
823/// compares less than the second component of another std::pair.
824struct less_second {
825  template <typename T> bool operator()(const T &lhs, const T &rhs) const {
826    return lhs.second < rhs.second;
827  }
828};
829 
830/// \brief Function object to apply a binary function to the first component of
831/// a std::pair.
832template<typename FuncTy>
833struct on_first {
834  FuncTy func;
835 
836  template <typename T>
837  auto operator()(const T &lhs, const T &rhs) const
838      -> decltype(func(lhs.first, rhs.first)) {
839    return func(lhs.first, rhs.first);
840  }
841};
842 
843// A subset of N3658. More stuff can be added as-needed.
844 
845/// Represents a compile-time sequence of integers.
846template <class T, T... I> struct integer_sequence {
847  using value_type = T;
848 
849  static constexpr size_t size() { return sizeof...(I); }
850};
851 
852/// Alias for the common case of a sequence of size_ts.
853template <size_t... I>
854struct index_sequence : integer_sequence<std::size_t, I...> {};
855 
856template <std::size_t N, std::size_t... I>
857struct build_index_impl : build_index_impl<N - 1, N - 1, I...> {};
858template <std::size_t... I>
859struct build_index_impl<0, I...> : index_sequence<I...> {};
860 
861/// Creates a compile-time integer sequence for a parameter pack.
862template <class... Ts>
863struct index_sequence_for : build_index_impl<sizeof...(Ts)> {};
864 
865/// Utility type to build an inheritance chain that makes it easy to rank
866/// overload candidates.
867template <int N> struct rank : rank<N - 1> {};
868template <> struct rank<0> {};
869 
870/// traits class for checking whether type T is one of any of the given
871/// types in the variadic list.
872template <typename T, typename... Ts> struct is_one_of {
873  static const bool value = false;
874};
875 
876template <typename T, typename U, typename... Ts>
877struct is_one_of<T, U, Ts...> {
878  static const bool value =
879      std::is_same<T, U>::value || is_one_of<T, Ts...>::value;
880};
881 
882/// traits class for checking whether type T is a base class for all
883///  the given types in the variadic list.
884template <typename T, typename... Ts> struct are_base_of {
885  static const bool value = true;
886};
887 
888template <typename T, typename U, typename... Ts>
889struct are_base_of<T, U, Ts...> {
890  static const bool value =
891      std::is_base_of<T, U>::value && are_base_of<T, Ts...>::value;
892};
893 
894//===----------------------------------------------------------------------===//
895//     Extra additions for arrays
896//===----------------------------------------------------------------------===//
897 
898/// Find the length of an array.
899template <class T, std::size_t N>
900constexpr inline size_t array_lengthof(T (&)[N]) {
901  return N;
902}
903 
904/// Adapt std::less<T> for array_pod_sort.
905template<typename T>
906inline int array_pod_sort_comparator(const void *P1, const void *P2) {
907  if (std::less<T>()(*reinterpret_cast<const T*>(P1),
908                     *reinterpret_cast<const T*>(P2)))
909    return -1;
910  if (std::less<T>()(*reinterpret_cast<const T*>(P2),
911                     *reinterpret_cast<const T*>(P1)))
912    return 1;
913  return 0;
914}
915 
916/// get_array_pod_sort_comparator - This is an internal helper function used to
917/// get type deduction of T right.
918template<typename T>
919inline int (*get_array_pod_sort_comparator(const T &))
920             (const void*, const void*) {
921  return array_pod_sort_comparator<T>;
922}
923 
924/// array_pod_sort - This sorts an array with the specified start and end
925/// extent.  This is just like std::sort, except that it calls qsort instead of
926/// using an inlined template.  qsort is slightly slower than std::sort, but
927/// most sorts are not performance critical in LLVM and std::sort has to be
928/// template instantiated for each type, leading to significant measured code
929/// bloat.  This function should generally be used instead of std::sort where
930/// possible.
931///
932/// This function assumes that you have simple POD-like types that can be
933/// compared with std::less and can be moved with memcpy.  If this isn't true,
934/// you should use std::sort.
935///
936/// NOTE: If qsort_r were portable, we could allow a custom comparator and
937/// default to std::less.
938template<class IteratorTy>
939inline void array_pod_sort(IteratorTy Start, IteratorTy End) {
940  // Don't inefficiently call qsort with one element or trigger undefined
941  // behavior with an empty sequence.
942  auto NElts = End - Start;
943  if (NElts <= 1) return;
944#ifdef EXPENSIVE_CHECKS
945  std::mt19937 Generator(std::random_device{}());
946  std::shuffle(Start, End, Generator);
947#endif
948  qsort(&*Start, NElts, sizeof(*Start), get_array_pod_sort_comparator(*Start));
949}
950 
951template <class IteratorTy>
952inline void array_pod_sort(
953    IteratorTy Start, IteratorTy End,
954    int (*Compare)(
955        const typename std::iterator_traits<IteratorTy>::value_type *,
956        const typename std::iterator_traits<IteratorTy>::value_type *)) {
957  // Don't inefficiently call qsort with one element or trigger undefined
958  // behavior with an empty sequence.
959  auto NElts = End - Start;
960  if (NElts <= 1) return;
961#ifdef EXPENSIVE_CHECKS
962  std::mt19937 Generator(std::random_device{}());
963  std::shuffle(Start, End, Generator);
964#endif
965  qsort(&*Start, NElts, sizeof(*Start),
966        reinterpret_cast<int (*)(const void *, const void *)>(Compare));
967}
968 
969// Provide wrappers to std::sort which shuffle the elements before sorting
970// to help uncover non-deterministic behavior (PR35135).
971template <typename IteratorTy>
972inline void sort(IteratorTy Start, IteratorTy End) {
973#ifdef EXPENSIVE_CHECKS
974  std::mt19937 Generator(std::random_device{}());
975  std::shuffle(Start, End, Generator);
976#endif
977  std::sort(Start, End);
978}
979 
980template <typename Container> inline void sort(Container &&C) {
981  llvm::sort(adl_begin(C), adl_end(C));
982}
983 
984template <typename IteratorTy, typename Compare>
985inline void sort(IteratorTy Start, IteratorTy End, Compare Comp) {
986#ifdef EXPENSIVE_CHECKS
987  std::mt19937 Generator(std::random_device{}());
988  std::shuffle(Start, End, Generator);
989#endif
990  std::sort(Start, End, Comp);
991}
992 
993template <typename Container, typename Compare>
994inline void sort(Container &&C, Compare Comp) {
995  llvm::sort(adl_begin(C), adl_end(C), Comp);
996}
997 
998//===----------------------------------------------------------------------===//
999//     Extra additions to <algorithm>
1000//===----------------------------------------------------------------------===//
1001 
1002/// For a container of pointers, deletes the pointers and then clears the
1003/// container.
1004template<typename Container>
1005void DeleteContainerPointers(Container &C) {
1006  for (auto V : C)
1007    delete V;
1008  C.clear();
1009}
1010 
1011/// In a container of pairs (usually a map) whose second element is a pointer,
1012/// deletes the second elements and then clears the container.
1013template<typename Container>
1014void DeleteContainerSeconds(Container &C) {
1015  for (auto &V : C)
1016    delete V.second;
1017  C.clear();
1018}
1019 
1020/// Get the size of a range. This is a wrapper function around std::distance
1021/// which is only enabled when the operation is O(1).
1022template <typename R>
1023auto size(R &&Range, typename std::enable_if<
1024                         std::is_same<typename std::iterator_traits<decltype(
1025                                          Range.begin())>::iterator_category,
1026                                      std::random_access_iterator_tag>::value,
1027                         void>::type * = nullptr)
1028    -> decltype(std::distance(Range.begin(), Range.end())) {
1029  return std::distance(Range.begin(), Range.end());
1030}
1031 
1032/// Provide wrappers to std::for_each which take ranges instead of having to
1033/// pass begin/end explicitly.
1034template <typename R, typename UnaryPredicate>
1035UnaryPredicate for_each(R &&Range, UnaryPredicate P) {
1036  return std::for_each(adl_begin(Range), adl_end(Range), P);
1037}
1038 
1039/// Provide wrappers to std::all_of which take ranges instead of having to pass
1040/// begin/end explicitly.
1041template <typename R, typename UnaryPredicate>
1042bool all_of(R &&Range, UnaryPredicate P) {
1043  return std::all_of(adl_begin(Range), adl_end(Range), P);
1044}
1045 
1046/// Provide wrappers to std::any_of which take ranges instead of having to pass
1047/// begin/end explicitly.
1048template <typename R, typename UnaryPredicate>
1049bool any_of(R &&Range, UnaryPredicate P) {
1050  return std::any_of(adl_begin(Range), adl_end(Range), P);
1051}
1052 
1053/// Provide wrappers to std::none_of which take ranges instead of having to pass
1054/// begin/end explicitly.
1055template <typename R, typename UnaryPredicate>
1056bool none_of(R &&Range, UnaryPredicate P) {
1057  return std::none_of(adl_begin(Range), adl_end(Range), P);
1058}
1059 
1060/// Provide wrappers to std::find which take ranges instead of having to pass
1061/// begin/end explicitly.
1062template <typename R, typename T>
1063auto find(R &&Range, const T &Val) -> decltype(adl_begin(Range)) {
1064  return std::find(adl_begin(Range), adl_end(Range), Val);
1065}
1066 
1067/// Provide wrappers to std::find_if which take ranges instead of having to pass
1068/// begin/end explicitly.
1069template <typename R, typename UnaryPredicate>
1070auto find_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1071  return std::find_if(adl_begin(Range), adl_end(Range), P);
1072}
1073 
1074template <typename R, typename UnaryPredicate>
1075auto find_if_not(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1076  return std::find_if_not(adl_begin(Range), adl_end(Range), P);
1077}
1078 
1079/// Provide wrappers to std::remove_if which take ranges instead of having to
1080/// pass begin/end explicitly.
1081template <typename R, typename UnaryPredicate>
1082auto remove_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1083  return std::remove_if(adl_begin(Range), adl_end(Range), P);
1084}
1085 
1086/// Provide wrappers to std::copy_if which take ranges instead of having to
1087/// pass begin/end explicitly.
1088template <typename R, typename OutputIt, typename UnaryPredicate>
1089OutputIt copy_if(R &&Range, OutputIt Out, UnaryPredicate P) {
1090  return std::copy_if(adl_begin(Range), adl_end(Range), Out, P);
1091}
1092 
1093template <typename R, typename OutputIt>
1094OutputIt copy(R &&Range, OutputIt Out) {
1095  return std::copy(adl_begin(Range), adl_end(Range), Out);
1096}
1097 
1098/// Wrapper function around std::find to detect if an element exists
1099/// in a container.
1100template <typename R, typename E>
1101bool is_contained(R &&Range, const E &Element) {
1102  return std::find(adl_begin(Range), adl_end(Range), Element) != adl_end(Range);
1103}
1104 
1105/// Wrapper function around std::count to count the number of times an element
1106/// \p Element occurs in the given range \p Range.
1107template <typename R, typename E>
1108auto count(R &&Range, const E &Element) ->
1109    typename std::iterator_traits<decltype(adl_begin(Range))>::difference_type {
1110  return std::count(adl_begin(Range), adl_end(Range), Element);
1111}
1112 
1113/// Wrapper function around std::count_if to count the number of times an
1114/// element satisfying a given predicate occurs in a range.
1115template <typename R, typename UnaryPredicate>
1116auto count_if(R &&Range, UnaryPredicate P) ->
1117    typename std::iterator_traits<decltype(adl_begin(Range))>::difference_type {
1118  return std::count_if(adl_begin(Range), adl_end(Range), P);
1119}
1120 
1121/// Wrapper function around std::transform to apply a function to a range and
1122/// store the result elsewhere.
1123template <typename R, typename OutputIt, typename UnaryPredicate>
1124OutputIt transform(R &&Range, OutputIt d_first, UnaryPredicate P) {
1125  return std::transform(adl_begin(Range), adl_end(Range), d_first, P);
1126}
1127 
1128/// Provide wrappers to std::partition which take ranges instead of having to
1129/// pass begin/end explicitly.
1130template <typename R, typename UnaryPredicate>
1131auto partition(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1132  return std::partition(adl_begin(Range), adl_end(Range), P);
1133}
1134 
1135/// Provide wrappers to std::lower_bound which take ranges instead of having to
1136/// pass begin/end explicitly.
1137template <typename R, typename ForwardIt>
1138auto lower_bound(R &&Range, ForwardIt I) -> decltype(adl_begin(Range)) {
1139  return std::lower_bound(adl_begin(Range), adl_end(Range), I);
1140}
1141 
1142template <typename R, typename ForwardIt, typename Compare>
1143auto lower_bound(R &&Range, ForwardIt I, Compare C)
1144    -> decltype(adl_begin(Range)) {
1145  return std::lower_bound(adl_begin(Range), adl_end(Range), I, C);
1146}
1147 
1148/// Provide wrappers to std::upper_bound which take ranges instead of having to
1149/// pass begin/end explicitly.
1150template <typename R, typename ForwardIt>
1151auto upper_bound(R &&Range, ForwardIt I) -> decltype(adl_begin(Range)) {
1152  return std::upper_bound(adl_begin(Range), adl_end(Range), I);
1153}
1154 
1155template <typename R, typename ForwardIt, typename Compare>
1156auto upper_bound(R &&Range, ForwardIt I, Compare C)
1157    -> decltype(adl_begin(Range)) {
1158  return std::upper_bound(adl_begin(Range), adl_end(Range), I, C);
1159}
1160/// Wrapper function around std::equal to detect if all elements
1161/// in a container are same.
1162template <typename R>
1163bool is_splat(R &&Range) {
1164  size_t range_size = size(Range);
1165  return range_size != 0 && (range_size == 1 ||
1166         std::equal(adl_begin(Range) + 1, adl_end(Range), adl_begin(Range)));
1167}
1168 
1169/// Given a range of type R, iterate the entire range and return a
1170/// SmallVector with elements of the vector.  This is useful, for example,
1171/// when you want to iterate a range and then sort the results.
1172template <unsigned Size, typename R>
1173SmallVector<typename std::remove_const<detail::ValueOfRange<R>>::type, Size>
1174to_vector(R &&Range) {
1175  return {adl_begin(Range), adl_end(Range)};
1176}
1177 
1178/// Provide a container algorithm similar to C++ Library Fundamentals v2's
1179/// `erase_if` which is equivalent to:
1180///
1181///   C.erase(remove_if(C, pred), C.end());
1182///
1183/// This version works for any container with an erase method call accepting
1184/// two iterators.
1185template <typename Container, typename UnaryPredicate>
1186void erase_if(Container &C, UnaryPredicate P) {
1187  C.erase(remove_if(C, P), C.end());
1188}
1189 
1190//===----------------------------------------------------------------------===//
1191//     Extra additions to <memory>
1192//===----------------------------------------------------------------------===//
1193 
1194// Implement make_unique according to N3656.
1195 
1196/// Constructs a `new T()` with the given args and returns a
1197///        `unique_ptr<T>` which owns the object.
1198///
1199/// Example:
1200///
1201///     auto p = make_unique<int>();
1202///     auto p = make_unique<std::tuple<int, int>>(0, 1);
1203template <class T, class... Args>
1204typename std::enable_if<!std::is_array<T>::value, std::unique_ptr<T>>::type
1205make_unique(Args &&... args) {
1206  return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
17
←
Memory is allocated→
1207}
1208 
1209/// Constructs a `new T[n]` with the given args and returns a
1210///        `unique_ptr<T[]>` which owns the object.
1211///
1212/// \param n size of the new array.
1213///
1214/// Example:
1215///
1216///     auto p = make_unique<int[]>(2); // value-initializes the array with 0's.
1217template <class T>
1218typename std::enable_if<std::is_array<T>::value && std::extent<T>::value == 0,
1219                        std::unique_ptr<T>>::type
1220make_unique(size_t n) {
1221  return std::unique_ptr<T>(new typename std::remove_extent<T>::type[n]());
1222}
1223 
1224/// This function isn't used and is only here to provide better compile errors.
1225template <class T, class... Args>
1226typename std::enable_if<std::extent<T>::value != 0>::type
1227make_unique(Args &&...) = delete;
1228 
1229struct FreeDeleter {
1230  void operator()(void* v) {
1231    ::free(v);
1232  }
1233};
1234 
1235template<typename First, typename Second>
1236struct pair_hash {
1237  size_t operator()(const std::pair<First, Second> &P) const {
1238    return std::hash<First>()(P.first) * 31 + std::hash<Second>()(P.second);
1239  }
1240};
1241 
1242/// A functor like C++14's std::less<void> in its absence.
1243struct less {
1244  template <typename A, typename B> bool operator()(A &&a, B &&b) const {
1245    return std::forward<A>(a) < std::forward<B>(b);
1246  }
1247};
1248 
1249/// A functor like C++14's std::equal<void> in its absence.
1250struct equal {
1251  template <typename A, typename B> bool operator()(A &&a, B &&b) const {
1252    return std::forward<A>(a) == std::forward<B>(b);
1253  }
1254};
1255 
1256/// Binary functor that adapts to any other binary functor after dereferencing
1257/// operands.
1258template <typename T> struct deref {
1259  T func;
1260 
1261  // Could be further improved to cope with non-derivable functors and
1262  // non-binary functors (should be a variadic template member function
1263  // operator()).
1264  template <typename A, typename B>
1265  auto operator()(A &lhs, B &rhs) const -> decltype(func(*lhs, *rhs)) {
1266    assert(lhs)((lhs) ? static_cast<void> (0) : __assert_fail ("lhs", "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/ADT/STLExtras.h"
, 1266, __PRETTY_FUNCTION__));
1267    assert(rhs)((rhs) ? static_cast<void> (0) : __assert_fail ("rhs", "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/ADT/STLExtras.h"
, 1267, __PRETTY_FUNCTION__));
1268    return func(*lhs, *rhs);
1269  }
1270};
1271 
1272namespace detail {
1273 
1274template <typename R> class enumerator_iter;
1275 
1276template <typename R> struct result_pair {
1277  friend class enumerator_iter<R>;
1278 
1279  result_pair() = default;
1280  result_pair(std::size_t Index, IterOfRange<R> Iter)
1281      : Index(Index), Iter(Iter) {}
1282 
1283  result_pair<R> &operator=(const result_pair<R> &Other) {
1284    Index = Other.Index;
1285    Iter = Other.Iter;
1286    return *this;
1287  }
1288 
1289  std::size_t index() const { return Index; }
1290  const ValueOfRange<R> &value() const { return *Iter; }
1291  ValueOfRange<R> &value() { return *Iter; }
1292 
1293private:
1294  std::size_t Index = std::numeric_limits<std::size_t>::max();
1295  IterOfRange<R> Iter;
1296};
1297 
1298template <typename R>
1299class enumerator_iter
1300    : public iterator_facade_base<
1301          enumerator_iter<R>, std::forward_iterator_tag, result_pair<R>,
1302          typename std::iterator_traits<IterOfRange<R>>::difference_type,
1303          typename std::iterator_traits<IterOfRange<R>>::pointer,
1304          typename std::iterator_traits<IterOfRange<R>>::reference> {
1305  using result_type = result_pair<R>;
1306 
1307public:
1308  explicit enumerator_iter(IterOfRange<R> EndIter)
1309      : Result(std::numeric_limits<size_t>::max(), EndIter) {}
1310 
1311  enumerator_iter(std::size_t Index, IterOfRange<R> Iter)
1312      : Result(Index, Iter) {}
1313 
1314  result_type &operator*() { return Result; }
1315  const result_type &operator*() const { return Result; }
1316 
1317  enumerator_iter<R> &operator++() {
1318    assert(Result.Index != std::numeric_limits<size_t>::max())((Result.Index != std::numeric_limits<size_t>::max()) ?
 static_cast<void> (0) : __assert_fail ("Result.Index != std::numeric_limits<size_t>::max()"
, "/build/llvm-toolchain-snapshot-8~svn345461/include/llvm/ADT/STLExtras.h"
, 1318, __PRETTY_FUNCTION__));
1319    ++Result.Iter;
1320    ++Result.Index;
1321    return *this;
1322  }
1323 
1324  bool operator==(const enumerator_iter<R> &RHS) const {
1325    // Don't compare indices here, only iterators.  It's possible for an end
1326    // iterator to have different indices depending on whether it was created
1327    // by calling std::end() versus incrementing a valid iterator.
1328    return Result.Iter == RHS.Result.Iter;
1329  }
1330 
1331  enumerator_iter<R> &operator=(const enumerator_iter<R> &Other) {
1332    Result = Other.Result;
1333    return *this;
1334  }
1335 
1336private:
1337  result_type Result;
1338};
1339 
1340template <typename R> class enumerator {
1341public:
1342  explicit enumerator(R &&Range) : TheRange(std::forward<R>(Range)) {}
1343 
1344  enumerator_iter<R> begin() {
1345    return enumerator_iter<R>(0, std::begin(TheRange));
1346  }
1347 
1348  enumerator_iter<R> end() {
1349    return enumerator_iter<R>(std::end(TheRange));
1350  }
1351 
1352private:
1353  R TheRange;
1354};
1355 
1356} // end namespace detail
1357 
1358/// Given an input range, returns a new range whose values are are pair (A,B)
1359/// such that A is the 0-based index of the item in the sequence, and B is
1360/// the value from the original sequence.  Example:
1361///
1362/// std::vector<char> Items = {'A', 'B', 'C', 'D'};
1363/// for (auto X : enumerate(Items)) {
1364///   printf("Item %d - %c\n", X.index(), X.value());
1365/// }
1366///
1367/// Output:
1368///   Item 0 - A
1369///   Item 1 - B
1370///   Item 2 - C
1371///   Item 3 - D
1372///
1373template <typename R> detail::enumerator<R> enumerate(R &&TheRange) {
1374  return detail::enumerator<R>(std::forward<R>(TheRange));
1375}
1376 
1377namespace detail {
1378 
1379template <typename F, typename Tuple, std::size_t... I>
1380auto apply_tuple_impl(F &&f, Tuple &&t, index_sequence<I...>)
1381    -> decltype(std::forward<F>(f)(std::get<I>(std::forward<Tuple>(t))...)) {
1382  return std::forward<F>(f)(std::get<I>(std::forward<Tuple>(t))...);
1383}
1384 
1385} // end namespace detail
1386 
1387/// Given an input tuple (a1, a2, ..., an), pass the arguments of the
1388/// tuple variadically to f as if by calling f(a1, a2, ..., an) and
1389/// return the result.
1390template <typename F, typename Tuple>
1391auto apply_tuple(F &&f, Tuple &&t) -> decltype(detail::apply_tuple_impl(
1392    std::forward<F>(f), std::forward<Tuple>(t),
1393    build_index_impl<
1394        std::tuple_size<typename std::decay<Tuple>::type>::value>{})) {
1395  using Indices = build_index_impl<
1396      std::tuple_size<typename std::decay<Tuple>::type>::value>;
1397 
1398  return detail::apply_tuple_impl(std::forward<F>(f), std::forward<Tuple>(t),
1399                                  Indices{});
1400}
1401 
1402} // end namespace llvm
1403 
1404#endif // LLVM_ADT_STLEXTRAS_H