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llvm-project/lld/COFF/PDB.cpp

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//===- PDB.cpp ------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "PDB.h"
#include "Chunks.h"
#include "Config.h"
#include "DebugTypes.h"
#include "Driver.h"
#include "SymbolTable.h"
#include "Symbols.h"
#include "TypeMerger.h"
#include "Writer.h"
#include "lld/Common/ErrorHandler.h"
#include "lld/Common/Timer.h"
#include "lld/Common/Threads.h"
#include "llvm/DebugInfo/CodeView/DebugFrameDataSubsection.h"
#include "llvm/DebugInfo/CodeView/DebugSubsectionRecord.h"
#include "llvm/DebugInfo/CodeView/GlobalTypeTableBuilder.h"
#include "llvm/DebugInfo/CodeView/LazyRandomTypeCollection.h"
#include "llvm/DebugInfo/CodeView/MergingTypeTableBuilder.h"
#include "llvm/DebugInfo/CodeView/RecordName.h"
#include "llvm/DebugInfo/CodeView/SymbolDeserializer.h"
#include "llvm/DebugInfo/CodeView/SymbolRecordHelpers.h"
#include "llvm/DebugInfo/CodeView/SymbolSerializer.h"
#include "llvm/DebugInfo/CodeView/TypeDeserializer.h"
#include "llvm/DebugInfo/CodeView/TypeDumpVisitor.h"
#include "llvm/DebugInfo/CodeView/TypeIndexDiscovery.h"
#include "llvm/DebugInfo/CodeView/TypeStreamMerger.h"
#include "llvm/DebugInfo/MSF/MSFBuilder.h"
#include "llvm/DebugInfo/MSF/MSFCommon.h"
#include "llvm/DebugInfo/PDB/GenericError.h"
#include "llvm/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.h"
#include "llvm/DebugInfo/PDB/Native/DbiStream.h"
#include "llvm/DebugInfo/PDB/Native/DbiStreamBuilder.h"
#include "llvm/DebugInfo/PDB/Native/GSIStreamBuilder.h"
#include "llvm/DebugInfo/PDB/Native/InfoStream.h"
#include "llvm/DebugInfo/PDB/Native/InfoStreamBuilder.h"
#include "llvm/DebugInfo/PDB/Native/NativeSession.h"
#include "llvm/DebugInfo/PDB/Native/PDBFile.h"
#include "llvm/DebugInfo/PDB/Native/PDBFileBuilder.h"
#include "llvm/DebugInfo/PDB/Native/PDBStringTableBuilder.h"
#include "llvm/DebugInfo/PDB/Native/TpiHashing.h"
#include "llvm/DebugInfo/PDB/Native/TpiStream.h"
#include "llvm/DebugInfo/PDB/Native/TpiStreamBuilder.h"
#include "llvm/DebugInfo/PDB/PDB.h"
#include "llvm/Object/COFF.h"
#include "llvm/Object/CVDebugRecord.h"
#include "llvm/Support/BinaryByteStream.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/JamCRC.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/ScopedPrinter.h"
#include <memory>
using namespace lld;
using namespace lld::coff;
using namespace llvm;
using namespace llvm::codeview;
using llvm::object::coff_section;
static ExitOnError ExitOnErr;
static Timer TotalPdbLinkTimer("PDB Emission (Cumulative)", Timer::root());
static Timer AddObjectsTimer("Add Objects", TotalPdbLinkTimer);
static Timer TypeMergingTimer("Type Merging", AddObjectsTimer);
static Timer SymbolMergingTimer("Symbol Merging", AddObjectsTimer);
static Timer GlobalsLayoutTimer("Globals Stream Layout", TotalPdbLinkTimer);
static Timer TpiStreamLayoutTimer("TPI Stream Layout", TotalPdbLinkTimer);
static Timer DiskCommitTimer("Commit to Disk", TotalPdbLinkTimer);
namespace {
class DebugSHandler;
class PDBLinker {
friend DebugSHandler;
public:
PDBLinker(SymbolTable *Symtab)
: Alloc(), Symtab(Symtab), Builder(Alloc), TMerger(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 info for each import file in the symbol table into the PDB.
void addImportFilesToPDB(ArrayRef<OutputSection *> OutputSections);
/// Link CodeView from a single object file into the target (output) PDB.
/// When a precompiled headers object is linked, its TPI map might be provided
/// externally.
void addObjFile(ObjFile *File, CVIndexMap *ExternIndexMap = nullptr);
/// 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);
/// Reads and makes available a PDB.
Expected<const CVIndexMap &> maybeMergeTypeServerPDB(ObjFile *File);
/// Merges a precompiled headers TPI map into the current TPI map. The
/// precompiled headers object will also be loaded and remapped in the
/// process.
Error mergeInPrecompHeaderObj(ObjFile *File, CVIndexMap *ObjectIndexMap);
/// Reads and makes available a precompiled headers object.
///
/// This is a requirement for objects compiled with cl.exe /Yu. In that
/// case, the referenced object (which was compiled with /Yc) has to be loaded
/// first. This is mainly because the current object's TPI stream has external
/// references to the precompiled headers object.
///
/// If the precompiled headers object was already loaded, this function will
/// simply return its (remapped) TPI map.
Expected<const CVIndexMap &> aquirePrecompObj(ObjFile *File);
/// Adds a precompiled headers object signature -> TPI mapping.
std::pair<CVIndexMap &, bool /*already there*/>
registerPrecompiledHeaders(uint32_t Signature);
void mergeSymbolRecords(ObjFile *File, const CVIndexMap &IndexMap,
std::vector<ulittle32_t *> &StringTableRefs,
BinaryStreamRef SymData);
/// 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);
// Print statistics regarding the final PDB
void printStats();
private:
BumpPtrAllocator Alloc;
SymbolTable *Symtab;
pdb::PDBFileBuilder Builder;
TypeMerger TMerger;
/// PDBs use a single global string table for filenames in the file checksum
/// table.
DebugStringTableSubsection PDBStrTab;
llvm::SmallString<128> NativePath;
std::vector<pdb::SecMapEntry> SectionMap;
/// Type index mappings of type server PDBs that we've loaded so far.
std::map<codeview::GUID, CVIndexMap> TypeServerIndexMappings;
/// Type index mappings of precompiled objects type map that we've loaded so
/// far.
std::map<uint32_t, CVIndexMap> PrecompTypeIndexMappings;
// For statistics
uint64_t GlobalSymbols = 0;
uint64_t ModuleSymbols = 0;
uint64_t PublicSymbols = 0;
};
class 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_INLINEELINES subsection. There can be only one of these per
/// object file.
DebugInlineeLinesSubsectionRef InlineeLines;
/// 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;
public:
DebugSHandler(PDBLinker &Linker, ObjFile &File, const CVIndexMap &IndexMap)
: Linker(Linker), File(File), IndexMap(IndexMap) {}
void handleDebugS(lld::coff::SectionChunk &DebugS);
std::shared_ptr<DebugInlineeLinesSubsection>
mergeInlineeLines(DebugChecksumsSubsection *NewChecksums);
void finish();
};
}
// Visual Studio's debugger requires absolute paths in various places in the
// PDB to work without additional configuration:
// https://docs.microsoft.com/en-us/visualstudio/debugger/debug-source-files-common-properties-solution-property-pages-dialog-box
static 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.
if (Config->PDBSourcePath.empty()) {
sys::path::native(FileName);
sys::fs::make_absolute(FileName);
return;
}
// Try to guess whether /PDBSOURCEPATH is a unix path or a windows path.
// Since PDB's are more of a Windows thing, we make this conservative and only
// decide that it's a unix path if we're fairly certain. Specifically, if
// it starts with a forward slash.
SmallString<128> AbsoluteFileName = Config->PDBSourcePath;
sys::path::Style GuessedStyle = AbsoluteFileName.startswith("/")
? sys::path::Style::posix
: sys::path::Style::windows;
sys::path::append(AbsoluteFileName, GuessedStyle, FileName);
sys::path::native(AbsoluteFileName, GuessedStyle);
sys::path::remove_dots(AbsoluteFileName, true, GuessedStyle);
FileName = std::move(AbsoluteFileName);
}
// A COFF .debug$H section is currently a clang extension. This function checks
// if a .debug$H section is in a format that we expect / understand, so that we
// can ignore any sections which are coincidentally also named .debug$H but do
// not contain a format we recognize.
static 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);
}
static Optional<ArrayRef<uint8_t>> getDebugH(ObjFile *File) {
SectionChunk *Sec =
SectionChunk::findByName(File->getDebugChunks(), ".debug$H");
if (!Sec)
return llvm::None;
ArrayRef<uint8_t> Contents = Sec->getContents();
if (!canUseDebugH(Contents))
return None;
return Contents;
}
static ArrayRef<GloballyHashedType>
getHashesFromDebugH(ArrayRef<uint8_t> DebugH) {
assert(canUseDebugH(DebugH));
DebugH = DebugH.drop_front(sizeof(object::debug_h_header));
uint32_t Count = DebugH.size() / sizeof(GloballyHashedType);
return {reinterpret_cast<const GloballyHashedType *>(DebugH.data()), Count};
}
static 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);
});
}
Expected<const CVIndexMap &>
PDBLinker::mergeDebugT(ObjFile *File, CVIndexMap *ObjectIndexMap) {
ScopedTimer T(TypeMergingTimer);
if (!File->DebugTypesObj)
return *ObjectIndexMap; // no Types stream
// Precompiled headers objects need to save the index map for further
// reference by other objects which use the precompiled headers.
if (File->DebugTypesObj->Kind == TpiSource::PCH) {
uint32_t PCHSignature = File->PCHSignature.getValueOr(0);
if (PCHSignature == 0)
fatal("No signature found for the precompiled headers OBJ (" +
File->getName() + ")");
// When a precompiled headers object comes first on the command-line, we
// update the mapping here. Otherwise, if an object referencing the
// precompiled headers object comes first, the mapping is created in
// aquirePrecompObj(), thus we would skip this block.
if (!ObjectIndexMap->IsPrecompiledTypeMap) {
auto R = registerPrecompiledHeaders(PCHSignature);
if (R.second)
fatal(
"A precompiled headers OBJ with the same signature was already "
"provided! (" +
File->getName() + ")");
ObjectIndexMap = &R.first;
}
}
if (File->DebugTypesObj->Kind == TpiSource::UsingPDB) {
// Look through type servers. If we've already seen this type server,
// don't merge any type information.
return maybeMergeTypeServerPDB(File);
}
CVTypeArray &Types = *File->DebugTypes;
if (File->DebugTypesObj->Kind == TpiSource::UsingPCH) {
// This object was compiled with /Yu, so process the corresponding
// precompiled headers object (/Yc) first. Some type indices in the current
// object are referencing data in the precompiled headers object, so we need
// both to be loaded.
Error E = mergeInPrecompHeaderObj(File, ObjectIndexMap);
if (E)
return std::move(E);
// Drop LF_PRECOMP record from the input stream, as it has been replaced
// with the precompiled headers Type stream in the mergeInPrecompHeaderObj()
// call above. Note that we can't just call Types.drop_front(), as we
// explicitly want to rebase the stream.
CVTypeArray::Iterator FirstType = Types.begin();
Types.setUnderlyingStream(
Types.getUnderlyingStream().drop_front(FirstType->RecordData.size()));
}
// 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(
TMerger.GlobalIDTable, TMerger.GlobalTypeTable,
ObjectIndexMap->TPIMap, Types, Hashes, File->PCHSignature))
fatal("codeview::mergeTypeAndIdRecords failed: " +
toString(std::move(Err)));
} else {
if (auto Err = mergeTypeAndIdRecords(TMerger.IDTable, TMerger.TypeTable,
ObjectIndexMap->TPIMap, Types,
File->PCHSignature))
fatal("codeview::mergeTypeAndIdRecords failed: " +
toString(std::move(Err)));
}
return *ObjectIndexMap;
}
Expected<const CVIndexMap &> PDBLinker::maybeMergeTypeServerPDB(ObjFile *File) {
Expected<llvm::pdb::NativeSession *> PDBSession = findTypeServerSource(File);
if (!PDBSession)
return PDBSession.takeError();
pdb::PDBFile &PDBFile = PDBSession.get()->getPDBFile();
pdb::InfoStream &Info = cantFail(PDBFile.getPDBInfoStream());
auto It = TypeServerIndexMappings.emplace(Info.getGuid(), CVIndexMap());
CVIndexMap &IndexMap = It.first->second;
if (!It.second)
return IndexMap; // already merged
// Mark this map as a type server map.
IndexMap.IsTypeServerMap = true;
Expected<pdb::TpiStream &> ExpectedTpi = PDBFile.getPDBTpiStream();
if (auto E = ExpectedTpi.takeError())
fatal("Type server does not have TPI stream: " + toString(std::move(E)));
Expected<pdb::TpiStream &> ExpectedIpi = PDBFile.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);
Optional<uint32_t> EndPrecomp;
// Merge TPI first, because the IPI stream will reference type indices.
if (auto Err =
mergeTypeRecords(TMerger.GlobalTypeTable, IndexMap.TPIMap,
ExpectedTpi->typeArray(), TpiHashes, EndPrecomp))
fatal("codeview::mergeTypeRecords failed: " + toString(std::move(Err)));
// Merge IPI.
if (auto Err = mergeIdRecords(TMerger.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(TMerger.TypeTable, IndexMap.TPIMap,
ExpectedTpi->typeArray()))
fatal("codeview::mergeTypeRecords failed: " + toString(std::move(Err)));
// Merge IPI.
if (auto Err = mergeIdRecords(TMerger.IDTable, IndexMap.TPIMap,
IndexMap.IPIMap, ExpectedIpi->typeArray()))
fatal("codeview::mergeIdRecords failed: " + toString(std::move(Err)));
}
return IndexMap;
}
Error PDBLinker::mergeInPrecompHeaderObj(ObjFile *File,
CVIndexMap *ObjectIndexMap) {
const PrecompRecord &Precomp =
retrieveDependencyInfo<PrecompRecord>(File->DebugTypesObj);
Expected<const CVIndexMap &> E = aquirePrecompObj(File);
if (!E)
return E.takeError();
const CVIndexMap &PrecompIndexMap = *E;
assert(PrecompIndexMap.IsPrecompiledTypeMap);
if (PrecompIndexMap.TPIMap.empty())
return Error::success();
assert(Precomp.getStartTypeIndex() == TypeIndex::FirstNonSimpleIndex);
assert(Precomp.getTypesCount() <= PrecompIndexMap.TPIMap.size());
// Use the previously remapped index map from the precompiled headers.
ObjectIndexMap->TPIMap.append(PrecompIndexMap.TPIMap.begin(),
PrecompIndexMap.TPIMap.begin() +
Precomp.getTypesCount());
return Error::success();
}
static bool equals_path(StringRef path1, StringRef path2) {
#if defined(_WIN32)
return path1.equals_lower(path2);
#else
return path1.equals(path2);
#endif
}
// Find by name an OBJ provided on the command line
static ObjFile *findObjByName(StringRef FileNameOnly) {
SmallString<128> CurrentPath;
for (ObjFile *F : ObjFile::Instances) {
StringRef CurrentFileName = sys::path::filename(F->getName());
// Compare based solely on the file name (link.exe behavior)
if (equals_path(CurrentFileName, FileNameOnly))
return F;
}
return nullptr;
}
std::pair<CVIndexMap &, bool /*already there*/>
PDBLinker::registerPrecompiledHeaders(uint32_t Signature) {
auto Insertion = PrecompTypeIndexMappings.insert({Signature, CVIndexMap()});
CVIndexMap &IndexMap = Insertion.first->second;
if (!Insertion.second)
return {IndexMap, true};
// Mark this map as a precompiled types map.
IndexMap.IsPrecompiledTypeMap = true;
return {IndexMap, false};
}
Expected<const CVIndexMap &> PDBLinker::aquirePrecompObj(ObjFile *File) {
const PrecompRecord &Precomp =
retrieveDependencyInfo<PrecompRecord>(File->DebugTypesObj);
// First, check if we already loaded the precompiled headers object with this
// signature. Return the type index mapping if we've already seen it.
auto R = registerPrecompiledHeaders(Precomp.getSignature());
if (R.second)
return R.first;
CVIndexMap &IndexMap = R.first;
// Cross-compile warning: given that Clang doesn't generate LF_PRECOMP
// records, we assume the OBJ comes from a Windows build of cl.exe. Thusly,
// the paths embedded in the OBJs are in the Windows format.
SmallString<128> PrecompFileName = sys::path::filename(
Precomp.getPrecompFilePath(), sys::path::Style::windows);
// link.exe requires that a precompiled headers object must always be provided
// on the command-line, even if that's not necessary.
auto PrecompFile = findObjByName(PrecompFileName);
if (!PrecompFile)
return createFileError(
PrecompFileName.str(),
make_error<pdb::PDBError>(pdb::pdb_error_code::external_cmdline_ref));
addObjFile(PrecompFile, &IndexMap);
if (!PrecompFile->PCHSignature)
fatal(PrecompFile->getName() + " is not a precompiled headers object");
if (Precomp.getSignature() != PrecompFile->PCHSignature.getValueOr(0))
return createFileError(
Precomp.getPrecompFilePath().str(),
make_error<pdb::PDBError>(pdb::pdb_error_code::signature_out_of_date));
return IndexMap;
}
static 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;
}
static void remapTypesInSymbolRecord(ObjFile *File, SymbolKind SymKind,
MutableArrayRef<uint8_t> RecordBytes,
const CVIndexMap &IndexMap,
ArrayRef<TiReference> TypeRefs) {
MutableArrayRef<uint8_t> Contents =
RecordBytes.drop_front(sizeof(RecordPrefix));
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;
}
}
}
}
static void
recordStringTableReferenceAtOffset(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);
}
static void
recordStringTableReferences(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, 8, 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;
}
}
static SymbolKind symbolKind(ArrayRef<uint8_t> RecordData) {
const RecordPrefix *Prefix =
reinterpret_cast<const RecordPrefix *>(RecordData.data());
return static_cast<SymbolKind>(uint16_t(Prefix->RecordKind));
}
/// MSVC translates S_PROC_ID_END to S_END, and S_[LG]PROC32_ID to S_[LG]PROC32
static 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(RecordData);
discoverTypeIndicesInSymbol(Sym, Refs);
assert(Refs.size() == 1);
assert(Refs.front().Count == 1);
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);
*TI = Indices[1];
}
Kind = (Kind == SymbolKind::S_GPROC32_ID) ? SymbolKind::S_GPROC32
: SymbolKind::S_LPROC32;
Prefix->RecordKind = uint16_t(Kind);
}
}
/// Copy the symbol record. In a PDB, symbol records must be 4 byte aligned.
/// The object file may not be aligned.
static MutableArrayRef<uint8_t>
copyAndAlignSymbol(const CVSymbol &Sym, MutableArrayRef<uint8_t> &AlignedMem) {
size_t Size = alignTo(Sym.length(), alignOf(CodeViewContainer::Pdb));
assert(Size >= 4 && "record too short");
assert(Size <= MaxRecordLength && "record too long");
assert(AlignedMem.size() >= Size && "didn't preallocate enough");
// Copy the symbol record and zero out any padding bytes.
MutableArrayRef<uint8_t> NewData = AlignedMem.take_front(Size);
AlignedMem = AlignedMem.drop_front(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 *>(NewData.data());
Prefix->RecordLen = Size - 2;
return NewData;
}
struct ScopeRecord {
ulittle32_t PtrParent;
ulittle32_t PtrEnd;
};
struct SymbolScope {
ScopeRecord *OpeningRecord;
uint32_t ScopeOffset;
};
static void scopeStackOpen(SmallVectorImpl<SymbolScope> &Stack,
uint32_t CurOffset, CVSymbol &Sym) {
assert(symbolOpensScope(Sym.kind()));
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);
}
static void scopeStackClose(SmallVectorImpl<SymbolScope> &Stack,
uint32_t CurOffset, InputFile *File) {
if (Stack.empty()) {
warn("symbol scopes are not balanced in " + File->getName());
return;
}
SymbolScope S = Stack.pop_back_val();
S.OpeningRecord->PtrEnd = CurOffset;
}
static bool symbolGoesInModuleStream(const CVSymbol &Sym, bool IsGlobalScope) {
switch (Sym.kind()) {
case SymbolKind::S_GDATA32:
case SymbolKind::S_CONSTANT:
// 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_UDT records go in the module stream if it is not a global S_UDT.
case SymbolKind::S_UDT:
return !IsGlobalScope;
// S_GDATA32 does not go in the module stream, but S_LDATA32 does.
case SymbolKind::S_LDATA32:
default:
return true;
}
}
static bool symbolGoesInGlobalsStream(const CVSymbol &Sym, bool IsGlobalScope) {
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;
// S_UDT records go in the globals stream if it is a global S_UDT.
case SymbolKind::S_UDT:
return IsGlobalScope;
default:
return false;
}
}
static void addGlobalSymbol(pdb::GSIStreamBuilder &Builder, uint16_t ModIndex,
unsigned SymOffset, 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 = ModIndex;
// For some reason, MSVC seems to add one to this value.
++PS.Module;
PS.Name = getSymbolName(Sym);
PS.SumName = 0;
PS.SymOffset = SymOffset;
Builder.addGlobalSymbol(PS);
break;
}
default:
llvm_unreachable("Invalid symbol kind!");
}
}
void PDBLinker::mergeSymbolRecords(ObjFile *File, const CVIndexMap &IndexMap,
std::vector<ulittle32_t *> &StringTableRefs,
BinaryStreamRef SymData) {
ArrayRef<uint8_t> SymsBuffer;
cantFail(SymData.readBytes(0, SymData.getLength(), SymsBuffer));
SmallVector<SymbolScope, 4> Scopes;
// Iterate every symbol to check if any need to be realigned, and if so, how
// much space we need to allocate for them.
bool NeedsRealignment = false;
unsigned TotalRealignedSize = 0;
auto EC = forEachCodeViewRecord<CVSymbol>(
SymsBuffer, [&](CVSymbol Sym) -> llvm::Error {
unsigned RealignedSize =
alignTo(Sym.length(), alignOf(CodeViewContainer::Pdb));
NeedsRealignment |= RealignedSize != Sym.length();
TotalRealignedSize += RealignedSize;
return Error::success();
});
// If any of the symbol record lengths was corrupt, ignore them all, warn
// about it, and move on.
if (EC) {
warn("corrupt symbol records in " + File->getName());
consumeError(std::move(EC));
return;
}
// If any symbol needed realignment, allocate enough contiguous memory for
// them all. Typically symbol subsections are small enough that this will not
// cause fragmentation.
MutableArrayRef<uint8_t> AlignedSymbolMem;
if (NeedsRealignment) {
void *AlignedData =
Alloc.Allocate(TotalRealignedSize, alignOf(CodeViewContainer::Pdb));
AlignedSymbolMem = makeMutableArrayRef(
reinterpret_cast<uint8_t *>(AlignedData), TotalRealignedSize);
}
// Iterate again, this time doing the real work.
unsigned CurSymOffset = File->ModuleDBI->getNextSymbolOffset();
ArrayRef<uint8_t> BulkSymbols;
cantFail(forEachCodeViewRecord<CVSymbol>(
SymsBuffer, [&](CVSymbol Sym) -> llvm::Error {
// Align the record if required.
MutableArrayRef<uint8_t> RecordBytes;
if (NeedsRealignment) {
RecordBytes = copyAndAlignSymbol(Sym, AlignedSymbolMem);
Sym = CVSymbol(RecordBytes);
} else {
// Otherwise, we can actually mutate the symbol directly, since we
// copied it to apply relocations.
RecordBytes = makeMutableArrayRef(
const_cast<uint8_t *>(Sym.data().data()), Sym.length());
}
// 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();
}
// Re-map all the type index references.
remapTypesInSymbolRecord(File, Sym.kind(), RecordBytes, IndexMap,
TypeRefs);
// An object file may have S_xxx_ID symbols, but these get converted to
// "real" symbols in a PDB.
translateIdSymbols(RecordBytes, TMerger.getIDTable());
Sym = CVSymbol(RecordBytes);
// 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(), RecordBytes, StringTableRefs);
// Fill in "Parent" and "End" fields by maintaining a stack of scopes.
if (symbolOpensScope(Sym.kind()))
scopeStackOpen(Scopes, CurSymOffset, Sym);
else if (symbolEndsScope(Sym.kind()))
scopeStackClose(Scopes, CurSymOffset, 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(Sym, Scopes.empty())) {
addGlobalSymbol(Builder.getGsiBuilder(),
File->ModuleDBI->getModuleIndex(), CurSymOffset, Sym);
++GlobalSymbols;
}
if (symbolGoesInModuleStream(Sym, Scopes.empty())) {
// Add symbols to the module in bulk. If this symbol is contiguous
// with the previous run of symbols to add, combine the ranges. If
// not, close the previous range of symbols and start a new one.
if (Sym.data().data() == BulkSymbols.end()) {
BulkSymbols = makeArrayRef(BulkSymbols.data(),
BulkSymbols.size() + Sym.length());
} else {
File->ModuleDBI->addSymbolsInBulk(BulkSymbols);
BulkSymbols = RecordBytes;
}
CurSymOffset += Sym.length();
++ModuleSymbols;
}
return Error::success();
}));
// Add any remaining symbols we've accumulated.
File->ModuleDBI->addSymbolsInBulk(BulkSymbols);
}
// Allocate memory for a .debug$S / .debug$F section and relocate it.
static ArrayRef<uint8_t> relocateDebugChunk(BumpPtrAllocator &Alloc,
SectionChunk &DebugChunk) {
uint8_t *Buffer = Alloc.Allocate<uint8_t>(DebugChunk.getSize());
assert(DebugChunk.getOutputSectionIdx() == 0 &&
"debug sections should not be in output sections");
DebugChunk.writeTo(Buffer);
return makeArrayRef(Buffer, DebugChunk.getSize());
}
static pdb::SectionContrib createSectionContrib(const Chunk *C, uint32_t Modi) {
OutputSection *OS = C ? C->getOutputSection() : nullptr;
pdb::SectionContrib SC;
memset(&SC, 0, sizeof(SC));
SC.ISect = OS ? OS->SectionIndex : llvm::pdb::kInvalidStreamIndex;
SC.Off = C && OS ? C->getRVA() - OS->getRVA() : 0;
SC.Size = C ? C->getSize() : -1;
if (auto *SecChunk = dyn_cast_or_null<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 ? OS->Header.Characteristics : 0;
SC.Imod = Modi;
}
SC.RelocCrc = 0; // FIXME
return SC;
}
static uint32_t
translateStringTableIndex(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);
}
void DebugSHandler::handleDebugS(lld::coff::SectionChunk &DebugS) {
DebugSubsectionArray Subsections;
ArrayRef<uint8_t> RelocatedDebugContents = SectionChunk::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() &&
"Encountered multiple string table subsections!");
ExitOnErr(CVStrTab.initialize(SS.getRecordData()));
break;
}
case DebugSubsectionKind::FileChecksums:
assert(!Checksums.valid() &&
"Encountered multiple checksum subsections!");
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::InlineeLines:
assert(!InlineeLines.valid() &&
"Encountered multiple inlinee lines subsections!");
ExitOnErr(InlineeLines.initialize(SS.getRecordData()));
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: {
Linker.mergeSymbolRecords(&File, IndexMap, StringTableReferences,
SS.getRecordData());
break;
}
case DebugSubsectionKind::CrossScopeImports:
case DebugSubsectionKind::CrossScopeExports:
// These appear to relate to cross-module optimization, so we might use
// these for ThinLTO.
break;
case DebugSubsectionKind::ILLines:
case DebugSubsectionKind::FuncMDTokenMap:
case DebugSubsectionKind::TypeMDTokenMap:
case DebugSubsectionKind::MergedAssemblyInput:
// These appear to relate to .Net assembly info.
break;
case DebugSubsectionKind::CoffSymbolRVA:
// Unclear what this is for.
break;
default:
warn("ignoring unknown debug$S subsection kind 0x" +
utohexstr(uint32_t(SS.kind())));
break;
}
}
}
static Expected<StringRef>
getFileName(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);
}
std::shared_ptr<DebugInlineeLinesSubsection>
DebugSHandler::mergeInlineeLines(DebugChecksumsSubsection *NewChecksums) {
auto NewInlineeLines = std::make_shared<DebugInlineeLinesSubsection>(
*NewChecksums, InlineeLines.hasExtraFiles());
for (const InlineeSourceLine &Line : InlineeLines) {
TypeIndex Inlinee = Line.Header->Inlinee;
uint32_t FileID = Line.Header->FileID;
uint32_t SourceLine = Line.Header->SourceLineNum;
ArrayRef<TypeIndex> TypeOrItemMap =
IndexMap.IsTypeServerMap ? IndexMap.IPIMap : IndexMap.TPIMap;
if (!remapTypeIndex(Inlinee, TypeOrItemMap)) {
log("ignoring inlinee line record in " + File.getName() +
" with bad inlinee index 0x" + utohexstr(Inlinee.getIndex()));
continue;
}
SmallString<128> Filename =
ExitOnErr(getFileName(CVStrTab, Checksums, FileID));
pdbMakeAbsolute(Filename);
NewInlineeLines->addInlineSite(Inlinee, Filename, SourceLine);
if (InlineeLines.hasExtraFiles()) {
for (uint32_t ExtraFileId : Line.ExtraFiles) {
Filename = ExitOnErr(getFileName(CVStrTab, Checksums, ExtraFileId));
pdbMakeAbsolute(Filename);
NewInlineeLines->addExtraFile(Filename);
}
}
}
return NewInlineeLines;
}
void 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$S sections with a checksums subsection must also contain a "
"string table subsection");
if (!StringTableReferences.empty())
warn("No StringTable subsection was encountered, but there are string "
"table references");
return;
}
// Rewrite string table indices in the Fpo Data and symbol records to refer to
// the global PDB string table instead of the object file string table.
for (DebugFrameDataSubsectionRef &FDS : NewFpoFrames) {
const ulittle32_t *Reloc = FDS.getRelocPtr();
for (codeview::FrameData FD : FDS) {
FD.RvaStart += *Reloc;
FD.FrameFunc =
translateStringTableIndex(FD.FrameFunc, CVStrTab, Linker.PDBStrTab);
DbiBuilder.addNewFpoData(FD);
}
}
for (ulittle32_t *Ref : StringTableReferences)
*Ref = translateStringTableIndex(*Ref, CVStrTab, Linker.PDBStrTab);
// Make a new file checksum table that refers to offsets in the PDB-wide
// string table. Generally the string table subsection appears after the
// checksum table, so we have to do this after looping over all the
// subsections.
auto NewChecksums = make_unique<DebugChecksumsSubsection>(Linker.PDBStrTab);
for (FileChecksumEntry &FC : Checksums) {
SmallString<128> Filename =
ExitOnErr(CVStrTab.getString(FC.FileNameOffset));
pdbMakeAbsolute(Filename);
ExitOnErr(DbiBuilder.addModuleSourceFile(*File.ModuleDBI, Filename));
NewChecksums->addChecksum(Filename, FC.Kind, FC.Checksum);
}
// Rewrite inlinee item indices if present.
if (InlineeLines.valid())
File.ModuleDBI->addDebugSubsection(mergeInlineeLines(NewChecksums.get()));
File.ModuleDBI->addDebugSubsection(std::move(NewChecksums));
}
void PDBLinker::addObjFile(ObjFile *File, CVIndexMap *ExternIndexMap) {
if (File->MergedIntoPDB)
return;
File->MergedIntoPDB = true;
// Before we can process symbol substreams from .debug$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, ExternIndexMap ? ExternIndexMap : &ObjectIndexMap);
// If the .debug$T sections fail to merge, assume there is no debug info.
if (!IndexMapResult) {
if (!Config->WarnDebugInfoUnusable) {
consumeError(IndexMapResult.takeError());
return;
}
warn("Cannot use debug info for '" + toString(File) + "' [LNK4099]\n" +
">>> failed to load reference " +
StringRef(toString(IndexMapResult.takeError())));
return;
}
ScopedTimer T(SymbolMergingTimer);
pdb::DbiStreamBuilder &DbiBuilder = Builder.getDbiBuilder();
DebugSHandler DSH(*this, *File, *IndexMapResult);
// Now do all live .debug$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();
}
// 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.
static void createModuleDBI(pdb::PDBFileBuilder &Builder) {
pdb::DbiStreamBuilder &DbiBuilder = Builder.getDbiBuilder();
SmallString<128> ObjName;
for (ObjFile *File : ObjFile::Instances) {
bool InArchive = !File->ParentName.empty();
ObjName = InArchive ? File->ParentName : File->getName();
pdbMakeAbsolute(ObjName);
StringRef ModName = InArchive ? File->getName() : StringRef(ObjName);
File->ModuleDBI = &ExitOnErr(DbiBuilder.addModuleInfo(ModName));
File->ModuleDBI->setObjFileName(ObjName);
ArrayRef<Chunk *> Chunks = File->getChunks();
uint32_t Modi = File->ModuleDBI->getModuleIndex();
for (Chunk *C : Chunks) {
auto *SecChunk = dyn_cast<SectionChunk>(C);
if (!SecChunk || !SecChunk->Live)
continue;
pdb::SectionContrib SC = createSectionContrib(SecChunk, Modi);
File->ModuleDBI->setFirstSectionContrib(SC);
break;
}
}
}
static 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");
Pub.Offset = Def->getRVA() - OS->getRVA();
Pub.Segment = OS->SectionIndex;
return Pub;
}
// Add all object files to the PDB. Merge .debug$T sections into IpiData and
// TpiData.
void PDBLinker::addObjectsToPDB() {
ScopedTimer T1(AddObjectsTimer);
createModuleDBI(Builder);
for (ObjFile *File : ObjFile::Instances)
addObjFile(File);
Builder.getStringTableBuilder().setStrings(PDBStrTab);
T1.stop();
// Construct TPI and IPI stream contents.
ScopedTimer T2(TpiStreamLayoutTimer);
addTypeInfo(Builder.getTpiBuilder(), TMerger.getTypeTable());
addTypeInfo(Builder.getIpiBuilder(), TMerger.getIDTable());
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()) {
PublicSymbols = Publics.size();
// Sort the public symbols and add them to the stream.
parallelSort(Publics, [](const PublicSym32 &L, const PublicSym32 &R) {
return L.Name < R.Name;
});
for (const PublicSym32 &Pub : Publics)
GsiBuilder.addPublicSymbol(Pub);
}
}
void PDBLinker::printStats() {
if (!Config->ShowSummary)
return;
SmallString<256> Buffer;
raw_svector_ostream Stream(Buffer);
Stream << center_justify("Summary", 80) << '\n'
<< std::string(80, '-') << '\n';
auto Print = [&](uint64_t V, StringRef S) {
Stream << format_decimal(V, 15) << " " << S << '\n';
};
Print(ObjFile::Instances.size(),
"Input OBJ files (expanded from all cmd-line inputs)");
Print(TypeServerIndexMappings.size(), "PDB type server dependencies");
Print(PrecompTypeIndexMappings.size(), "Precomp OBJ dependencies");
Print(TMerger.getTypeTable().size() + TMerger.getIDTable().size(),
"Merged TPI records");
Print(PDBStrTab.size(), "Output PDB strings");
Print(GlobalSymbols, "Global symbol records");
Print(ModuleSymbols, "Module symbol records");
Print(PublicSymbols, "Public symbol records");
message(Buffer);
}
void 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));
}
}
static 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");
}
}
// Mimic MSVC which surrounds arguments containing whitespace with quotes.
// Double double-quotes are handled, so that the resulting string can be
// executed again on the cmd-line.
static std::string quote(ArrayRef<StringRef> Args) {
std::string R;
R.reserve(256);
for (StringRef A : Args) {
if (!R.empty())
R.push_back(' ');
bool HasWS = A.find(' ') != StringRef::npos;
bool HasQ = A.find('"') != StringRef::npos;
if (HasWS || HasQ)
R.push_back('"');
if (HasQ) {
SmallVector<StringRef, 4> S;
A.split(S, '"');
R.append(join(S, "\"\""));
} else {
R.append(A);
}
if (HasWS || HasQ)
R.push_back('"');
}
return R;
}
static void fillLinkerVerRecord(Compile3Sym &CS) {
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);
}
static void addCommonLinkerModuleSymbols(StringRef Path,
pdb::DbiModuleDescriptorBuilder &Mod,
BumpPtrAllocator &Allocator) {
ObjNameSym ONS(SymbolRecordKind::ObjNameSym);
EnvBlockSym EBS(SymbolRecordKind::EnvBlockSym);
Compile3Sym CS(SymbolRecordKind::Compile3Sym);
fillLinkerVerRecord(CS);
ONS.Name = "* Linker *";
ONS.Signature = 0;
ArrayRef<StringRef> Args = makeArrayRef(Config->Argv).drop_front();
std::string ArgStr = quote(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));
}
static void addLinkerModuleCoffGroup(PartialSection *Sec,
pdb::DbiModuleDescriptorBuilder &Mod,
OutputSection &OS,
BumpPtrAllocator &Allocator) {
// If there's a section, there's at least one chunk
assert(!Sec->Chunks.empty());
const Chunk *firstChunk = *Sec->Chunks.begin();
const Chunk *lastChunk = *Sec->Chunks.rbegin();
// Emit COFF group
CoffGroupSym CGS(SymbolRecordKind::CoffGroupSym);
CGS.Name = Sec->Name;
CGS.Segment = OS.SectionIndex;
CGS.Offset = firstChunk->getRVA() - OS.getRVA();
CGS.Size = lastChunk->getRVA() + lastChunk->getSize() - firstChunk->getRVA();
CGS.Characteristics = Sec->Characteristics;
// Somehow .idata sections & sections groups in the debug symbol stream have
// the "write" flag set. However the section header for the corresponding
// .idata section doesn't have it.
if (CGS.Name.startswith(".idata"))
CGS.Characteristics |= llvm::COFF::IMAGE_SCN_MEM_WRITE;
Mod.addSymbol(codeview::SymbolSerializer::writeOneSymbol(
CGS, Allocator, CodeViewContainer::Pdb));
}
static 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));
// Skip COFF groups in MinGW because it adds a significant footprint to the
// PDB, due to each function being in its own section
if (Config->MinGW)
return;
// Output COFF groups for individual chunks of this section.
for (PartialSection *Sec : OS.ContribSections) {
addLinkerModuleCoffGroup(Sec, Mod, OS, Allocator);
}
}
// Add all import files as modules to the PDB.
void PDBLinker::addImportFilesToPDB(ArrayRef<OutputSection *> OutputSections) {
if (ImportFile::Instances.empty())
return;
std::map<std::string, llvm::pdb::DbiModuleDescriptorBuilder *> DllToModuleDbi;
for (ImportFile *File : ImportFile::Instances) {
if (!File->Live)
continue;
if (!File->ThunkSym)
continue;
if (!File->ThunkLive)
continue;
std::string DLL = StringRef(File->DLLName).lower();
llvm::pdb::DbiModuleDescriptorBuilder *&Mod = DllToModuleDbi[DLL];
if (!Mod) {
pdb::DbiStreamBuilder &DbiBuilder = Builder.getDbiBuilder();
SmallString<128> LibPath = File->ParentName;
pdbMakeAbsolute(LibPath);
sys::path::native(LibPath);
// Name modules similar to MSVC's link.exe.
// The first module is the simple dll filename
llvm::pdb::DbiModuleDescriptorBuilder &FirstMod =
ExitOnErr(DbiBuilder.addModuleInfo(File->DLLName));
FirstMod.setObjFileName(LibPath);
pdb::SectionContrib SC =
createSectionContrib(nullptr, llvm::pdb::kInvalidStreamIndex);
FirstMod.setFirstSectionContrib(SC);
// The second module is where the import stream goes.
Mod = &ExitOnErr(DbiBuilder.addModuleInfo("Import:" + File->DLLName));
Mod->setObjFileName(LibPath);
}
DefinedImportThunk *Thunk = cast<DefinedImportThunk>(File->ThunkSym);
Chunk *ThunkChunk = Thunk->getChunk();
OutputSection *ThunkOS = ThunkChunk->getOutputSection();
ObjNameSym ONS(SymbolRecordKind::ObjNameSym);
Compile3Sym CS(SymbolRecordKind::Compile3Sym);
Thunk32Sym TS(SymbolRecordKind::Thunk32Sym);
ScopeEndSym ES(SymbolRecordKind::ScopeEndSym);
ONS.Name = File->DLLName;
ONS.Signature = 0;
fillLinkerVerRecord(CS);
TS.Name = Thunk->getName();
TS.Parent = 0;
TS.End = 0;
TS.Next = 0;
TS.Thunk = ThunkOrdinal::Standard;
TS.Length = ThunkChunk->getSize();
TS.Segment = ThunkOS->SectionIndex;
TS.Offset = ThunkChunk->getRVA() - ThunkOS->getRVA();
Mod->addSymbol(codeview::SymbolSerializer::writeOneSymbol(
ONS, Alloc, CodeViewContainer::Pdb));
Mod->addSymbol(codeview::SymbolSerializer::writeOneSymbol(
CS, Alloc, CodeViewContainer::Pdb));
SmallVector<SymbolScope, 4> Scopes;
CVSymbol NewSym = codeview::SymbolSerializer::writeOneSymbol(
TS, Alloc, CodeViewContainer::Pdb);
scopeStackOpen(Scopes, Mod->getNextSymbolOffset(), NewSym);
Mod->addSymbol(NewSym);
NewSym = codeview::SymbolSerializer::writeOneSymbol(ES, Alloc,
CodeViewContainer::Pdb);
scopeStackClose(Scopes, Mod->getNextSymbolOffset(), File);
Mod->addSymbol(NewSym);
pdb::SectionContrib SC =
createSectionContrib(Thunk->getChunk(), Mod->getModuleIndex());
Mod->setFirstSectionContrib(SC);
}
}
// Creates a PDB file.
void 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();
PDB.addImportFilesToPDB(OutputSections);
PDB.addSections(OutputSections, SectionTable);
PDB.addNatvisFiles();
ScopedTimer T2(DiskCommitTimer);
codeview::GUID Guid;
PDB.commit(&Guid);
memcpy(&BuildId->PDB70.Signature, &Guid, 16);
T2.stop();
T1.stop();
PDB.printStats();
}
void 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);
}
void 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);
}
}
// The * Linker * first section contrib is only used along with /INCREMENTAL,
// to provide trampolines thunks for incremental function patching. Set this
// as "unused" because LLD doesn't support /INCREMENTAL link.
pdb::SectionContrib SC =
createSectionContrib(nullptr, llvm::pdb::kInvalidStreamIndex);
LinkerModule.setFirstSectionContrib(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));
}
void PDBLinker::commit(codeview::GUID *Guid) {
// Write to a file.
ExitOnErr(Builder.commit(Config->PDBPath, Guid));
}
static 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");
}
}
// Try to find a line table for the given offset Addr into the given chunk C.
// If a line table was found, the line table, the string and checksum tables
// that are used to interpret the line table, and the offset of Addr in the line
// table are stored in the output arguments. Returns whether a line table was
// found.
static 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->getRelocs()) {
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 =
SectionChunk::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() &&
"Encountered multiple string table subsections!");
ExitOnErr(CVStrTab.initialize(SS.getRecordData()));
break;
}
case DebugSubsectionKind::FileChecksums:
assert(!Checksums.valid() &&
"Encountered multiple checksum subsections!");
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() &&
"Encountered multiple line tables for function!");
ExitOnErr(Lines.initialize(BinaryStreamReader(Ref)));
OffsetInLinetable = Addr - OffsetInC;
break;
}
default:
break;
}
if (CVStrTab.valid() && Checksums.valid() && Lines.header())
return true;
}
}
return false;
}
// Use CodeView line tables to resolve a file and line number for the given
// offset into the given chunk and return them, or {"", 0} if a line table was
// not found.
std::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};
Optional<uint32_t> NameIndex;
Optional<uint32_t> LineNumber;
for (LineColumnEntry &Entry : Lines) {
for (const LineNumberEntry &LN : Entry.LineNumbers) {
LineInfo LI(LN.Flags);
if (LN.Offset > OffsetInLinetable) {
if (!NameIndex) {
NameIndex = Entry.NameIndex;
LineNumber = LI.getStartLine();
}
StringRef Filename =
ExitOnErr(getFileName(CVStrTab, Checksums, *NameIndex));
return {Filename, *LineNumber};
}
NameIndex = Entry.NameIndex;
LineNumber = LI.getStartLine();
}
}
if (!NameIndex)
return {"", 0};
StringRef Filename = ExitOnErr(getFileName(CVStrTab, Checksums, *NameIndex));
return {Filename, *LineNumber};
}
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