1 //===- PDB.cpp ------------------------------------------------------------===//
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
14 #include "SymbolTable.h"
17 #include "lld/Common/ErrorHandler.h"
18 #include "llvm/DebugInfo/CodeView/CVDebugRecord.h"
19 #include "llvm/DebugInfo/CodeView/DebugSubsectionRecord.h"
20 #include "llvm/DebugInfo/CodeView/GlobalTypeTableBuilder.h"
21 #include "llvm/DebugInfo/CodeView/LazyRandomTypeCollection.h"
22 #include "llvm/DebugInfo/CodeView/MergingTypeTableBuilder.h"
23 #include "llvm/DebugInfo/CodeView/RecordName.h"
24 #include "llvm/DebugInfo/CodeView/SymbolDeserializer.h"
25 #include "llvm/DebugInfo/CodeView/SymbolSerializer.h"
26 #include "llvm/DebugInfo/CodeView/TypeDeserializer.h"
27 #include "llvm/DebugInfo/CodeView/TypeDumpVisitor.h"
28 #include "llvm/DebugInfo/CodeView/TypeIndexDiscovery.h"
29 #include "llvm/DebugInfo/CodeView/TypeStreamMerger.h"
30 #include "llvm/DebugInfo/MSF/MSFBuilder.h"
31 #include "llvm/DebugInfo/MSF/MSFCommon.h"
32 #include "llvm/DebugInfo/PDB/GenericError.h"
33 #include "llvm/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.h"
34 #include "llvm/DebugInfo/PDB/Native/DbiStream.h"
35 #include "llvm/DebugInfo/PDB/Native/DbiStreamBuilder.h"
36 #include "llvm/DebugInfo/PDB/Native/GSIStreamBuilder.h"
37 #include "llvm/DebugInfo/PDB/Native/InfoStream.h"
38 #include "llvm/DebugInfo/PDB/Native/InfoStreamBuilder.h"
39 #include "llvm/DebugInfo/PDB/Native/NativeSession.h"
40 #include "llvm/DebugInfo/PDB/Native/PDBFile.h"
41 #include "llvm/DebugInfo/PDB/Native/PDBFileBuilder.h"
42 #include "llvm/DebugInfo/PDB/Native/PDBStringTableBuilder.h"
43 #include "llvm/DebugInfo/PDB/Native/TpiHashing.h"
44 #include "llvm/DebugInfo/PDB/Native/TpiStream.h"
45 #include "llvm/DebugInfo/PDB/Native/TpiStreamBuilder.h"
46 #include "llvm/DebugInfo/PDB/PDB.h"
47 #include "llvm/Object/COFF.h"
48 #include "llvm/Support/BinaryByteStream.h"
49 #include "llvm/Support/Endian.h"
50 #include "llvm/Support/JamCRC.h"
51 #include "llvm/Support/Path.h"
52 #include "llvm/Support/ScopedPrinter.h"
56 using namespace lld::coff;
58 using namespace llvm::codeview;
60 using llvm::object::coff_section;
62 static ExitOnError ExitOnErr;
65 /// Map from type index and item index in a type server PDB to the
66 /// corresponding index in the destination PDB.
68 SmallVector<TypeIndex, 0> TPIMap;
69 SmallVector<TypeIndex, 0> IPIMap;
70 bool IsTypeServerMap = false;
75 PDBLinker(SymbolTable *Symtab)
76 : Alloc(), Symtab(Symtab), Builder(Alloc), TypeTable(Alloc),
77 IDTable(Alloc), GlobalTypeTable(Alloc), GlobalIDTable(Alloc) {}
79 /// Emit the basic PDB structure: initial streams, headers, etc.
80 void initialize(const llvm::codeview::DebugInfo &BuildId);
82 /// Link CodeView from each object file in the symbol table into the PDB.
83 void addObjectsToPDB();
85 /// Link CodeView from a single object file into the PDB.
86 void addObjFile(ObjFile *File);
88 /// Produce a mapping from the type and item indices used in the object
89 /// file to those in the destination PDB.
91 /// If the object file uses a type server PDB (compiled with /Zi), merge TPI
92 /// and IPI from the type server PDB and return a map for it. Each unique type
93 /// server PDB is merged at most once, so this may return an existing index
96 /// If the object does not use a type server PDB (compiled with /Z7), we merge
97 /// all the type and item records from the .debug$S stream and fill in the
98 /// caller-provided ObjectIndexMap.
99 const CVIndexMap &mergeDebugT(ObjFile *File, CVIndexMap &ObjectIndexMap);
101 const CVIndexMap &maybeMergeTypeServerPDB(ObjFile *File,
102 TypeServer2Record &TS);
104 /// Add the section map and section contributions to the PDB.
105 void addSections(ArrayRef<OutputSection *> OutputSections,
106 ArrayRef<uint8_t> SectionTable);
108 void addSectionContrib(pdb::DbiModuleDescriptorBuilder &LinkerModule,
109 OutputSection *OS, Chunk *C);
111 /// Write the PDB to disk.
115 BumpPtrAllocator Alloc;
119 pdb::PDBFileBuilder Builder;
121 /// Type records that will go into the PDB TPI stream.
122 MergingTypeTableBuilder TypeTable;
124 /// Item records that will go into the PDB IPI stream.
125 MergingTypeTableBuilder IDTable;
127 /// Type records that will go into the PDB TPI stream (for /DEBUG:GHASH)
128 GlobalTypeTableBuilder GlobalTypeTable;
130 /// Item records that will go into the PDB IPI stream (for /DEBUG:GHASH)
131 GlobalTypeTableBuilder GlobalIDTable;
133 /// PDBs use a single global string table for filenames in the file checksum
135 DebugStringTableSubsection PDBStrTab;
137 llvm::SmallString<128> NativePath;
139 std::vector<pdb::SecMapEntry> SectionMap;
141 /// Type index mappings of type server PDBs that we've loaded so far.
142 std::map<GUID, CVIndexMap> TypeServerIndexMappings;
146 static SectionChunk *findByName(ArrayRef<SectionChunk *> Sections,
148 for (SectionChunk *C : Sections)
149 if (C->getSectionName() == Name)
154 static ArrayRef<uint8_t> consumeDebugMagic(ArrayRef<uint8_t> Data,
156 // First 4 bytes are section magic.
158 fatal(SecName + " too short");
159 if (support::endian::read32le(Data.data()) != COFF::DEBUG_SECTION_MAGIC)
160 fatal(SecName + " has an invalid magic");
161 return Data.slice(4);
164 static ArrayRef<uint8_t> getDebugSection(ObjFile *File, StringRef SecName) {
165 if (SectionChunk *Sec = findByName(File->getDebugChunks(), SecName))
166 return consumeDebugMagic(Sec->getContents(), SecName);
170 // A COFF .debug$H section is currently a clang extension. This function checks
171 // if a .debug$H section is in a format that we expect / understand, so that we
172 // can ignore any sections which are coincidentally also named .debug$H but do
173 // not contain a format we recognize.
174 static bool canUseDebugH(ArrayRef<uint8_t> DebugH) {
175 if (DebugH.size() < sizeof(object::debug_h_header))
178 reinterpret_cast<const object::debug_h_header *>(DebugH.data());
179 DebugH = DebugH.drop_front(sizeof(object::debug_h_header));
180 return Header->Magic == COFF::DEBUG_HASHES_SECTION_MAGIC &&
181 Header->Version == 0 &&
182 Header->HashAlgorithm == uint16_t(GlobalTypeHashAlg::SHA1) &&
183 (DebugH.size() % 20 == 0);
186 static Optional<ArrayRef<uint8_t>> getDebugH(ObjFile *File) {
187 SectionChunk *Sec = findByName(File->getDebugChunks(), ".debug$H");
190 ArrayRef<uint8_t> Contents = Sec->getContents();
191 if (!canUseDebugH(Contents))
196 static ArrayRef<GloballyHashedType>
197 getHashesFromDebugH(ArrayRef<uint8_t> DebugH) {
198 assert(canUseDebugH(DebugH));
200 DebugH = DebugH.drop_front(sizeof(object::debug_h_header));
201 uint32_t Count = DebugH.size() / sizeof(GloballyHashedType);
202 return {reinterpret_cast<const GloballyHashedType *>(DebugH.data()), Count};
205 static void addTypeInfo(pdb::TpiStreamBuilder &TpiBuilder,
206 TypeCollection &TypeTable) {
207 // Start the TPI or IPI stream header.
208 TpiBuilder.setVersionHeader(pdb::PdbTpiV80);
210 // Flatten the in memory type table and hash each type.
211 TypeTable.ForEachRecord([&](TypeIndex TI, const CVType &Type) {
212 auto Hash = pdb::hashTypeRecord(Type);
213 if (auto E = Hash.takeError())
214 fatal("type hashing error");
215 TpiBuilder.addTypeRecord(Type.RecordData, *Hash);
219 static Optional<TypeServer2Record>
220 maybeReadTypeServerRecord(CVTypeArray &Types) {
221 auto I = Types.begin();
222 if (I == Types.end())
224 const CVType &Type = *I;
225 if (Type.kind() != LF_TYPESERVER2)
227 TypeServer2Record TS;
228 if (auto EC = TypeDeserializer::deserializeAs(const_cast<CVType &>(Type), TS))
229 fatal("error reading type server record: " + toString(std::move(EC)));
230 return std::move(TS);
233 const CVIndexMap &PDBLinker::mergeDebugT(ObjFile *File,
234 CVIndexMap &ObjectIndexMap) {
235 ArrayRef<uint8_t> Data = getDebugSection(File, ".debug$T");
237 return ObjectIndexMap;
239 BinaryByteStream Stream(Data, support::little);
241 BinaryStreamReader Reader(Stream);
242 if (auto EC = Reader.readArray(Types, Reader.getLength()))
243 fatal("Reader::readArray failed: " + toString(std::move(EC)));
245 // Look through type servers. If we've already seen this type server, don't
246 // merge any type information.
247 if (Optional<TypeServer2Record> TS = maybeReadTypeServerRecord(Types))
248 return maybeMergeTypeServerPDB(File, *TS);
250 // This is a /Z7 object. Fill in the temporary, caller-provided
252 if (Config->DebugGHashes) {
253 ArrayRef<GloballyHashedType> Hashes;
254 std::vector<GloballyHashedType> OwnedHashes;
255 if (Optional<ArrayRef<uint8_t>> DebugH = getDebugH(File))
256 Hashes = getHashesFromDebugH(*DebugH);
258 OwnedHashes = GloballyHashedType::hashTypes(Types);
259 Hashes = OwnedHashes;
262 if (auto Err = mergeTypeAndIdRecords(GlobalIDTable, GlobalTypeTable,
263 ObjectIndexMap.TPIMap, Types, Hashes))
264 fatal("codeview::mergeTypeAndIdRecords failed: " +
265 toString(std::move(Err)));
267 if (auto Err = mergeTypeAndIdRecords(IDTable, TypeTable,
268 ObjectIndexMap.TPIMap, Types))
269 fatal("codeview::mergeTypeAndIdRecords failed: " +
270 toString(std::move(Err)));
272 return ObjectIndexMap;
275 static Expected<std::unique_ptr<pdb::NativeSession>>
276 tryToLoadPDB(const GUID &GuidFromObj, StringRef TSPath) {
277 ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr = MemoryBuffer::getFile(
278 TSPath, /*FileSize=*/-1, /*RequiresNullTerminator=*/false);
280 return errorCodeToError(MBOrErr.getError());
282 std::unique_ptr<pdb::IPDBSession> ThisSession;
283 if (auto EC = pdb::NativeSession::createFromPdb(
284 MemoryBuffer::getMemBuffer(Driver->takeBuffer(std::move(*MBOrErr)),
285 /*RequiresNullTerminator=*/false),
287 return std::move(EC);
289 std::unique_ptr<pdb::NativeSession> NS(
290 static_cast<pdb::NativeSession *>(ThisSession.release()));
291 pdb::PDBFile &File = NS->getPDBFile();
292 auto ExpectedInfo = File.getPDBInfoStream();
293 // All PDB Files should have an Info stream.
295 return ExpectedInfo.takeError();
297 // Just because a file with a matching name was found and it was an actual
298 // PDB file doesn't mean it matches. For it to match the InfoStream's GUID
299 // must match the GUID specified in the TypeServer2 record.
300 if (ExpectedInfo->getGuid() != GuidFromObj)
301 return make_error<pdb::GenericError>(
302 pdb::generic_error_code::type_server_not_found, TSPath);
304 return std::move(NS);
307 const CVIndexMap &PDBLinker::maybeMergeTypeServerPDB(ObjFile *File,
308 TypeServer2Record &TS) {
309 // First, check if we already loaded a PDB with this GUID. Return the type
310 // index mapping if we have it.
311 auto Insertion = TypeServerIndexMappings.insert({TS.getGuid(), CVIndexMap()});
312 CVIndexMap &IndexMap = Insertion.first->second;
313 if (!Insertion.second)
316 // Mark this map as a type server map.
317 IndexMap.IsTypeServerMap = true;
319 // Check for a PDB at:
320 // 1. The given file path
321 // 2. Next to the object file or archive file
322 auto ExpectedSession = tryToLoadPDB(TS.getGuid(), TS.getName());
323 if (!ExpectedSession) {
324 consumeError(ExpectedSession.takeError());
325 StringRef LocalPath =
326 !File->ParentName.empty() ? File->ParentName : File->getName();
327 SmallString<128> Path = sys::path::parent_path(LocalPath);
329 Path, sys::path::filename(TS.getName(), sys::path::Style::windows));
330 ExpectedSession = tryToLoadPDB(TS.getGuid(), Path);
332 if (auto E = ExpectedSession.takeError())
333 fatal("Type server PDB was not found: " + toString(std::move(E)));
335 auto ExpectedTpi = (*ExpectedSession)->getPDBFile().getPDBTpiStream();
336 if (auto E = ExpectedTpi.takeError())
337 fatal("Type server does not have TPI stream: " + toString(std::move(E)));
338 auto ExpectedIpi = (*ExpectedSession)->getPDBFile().getPDBIpiStream();
339 if (auto E = ExpectedIpi.takeError())
340 fatal("Type server does not have TPI stream: " + toString(std::move(E)));
342 if (Config->DebugGHashes) {
343 // PDBs do not actually store global hashes, so when merging a type server
344 // PDB we have to synthesize global hashes. To do this, we first synthesize
345 // global hashes for the TPI stream, since it is independent, then we
346 // synthesize hashes for the IPI stream, using the hashes for the TPI stream
348 auto TpiHashes = GloballyHashedType::hashTypes(ExpectedTpi->typeArray());
350 GloballyHashedType::hashIds(ExpectedIpi->typeArray(), TpiHashes);
352 // Merge TPI first, because the IPI stream will reference type indices.
353 if (auto Err = mergeTypeRecords(GlobalTypeTable, IndexMap.TPIMap,
354 ExpectedTpi->typeArray(), TpiHashes))
355 fatal("codeview::mergeTypeRecords failed: " + toString(std::move(Err)));
359 mergeIdRecords(GlobalIDTable, IndexMap.TPIMap, IndexMap.IPIMap,
360 ExpectedIpi->typeArray(), IpiHashes))
361 fatal("codeview::mergeIdRecords failed: " + toString(std::move(Err)));
363 // Merge TPI first, because the IPI stream will reference type indices.
364 if (auto Err = mergeTypeRecords(TypeTable, IndexMap.TPIMap,
365 ExpectedTpi->typeArray()))
366 fatal("codeview::mergeTypeRecords failed: " + toString(std::move(Err)));
369 if (auto Err = mergeIdRecords(IDTable, IndexMap.TPIMap, IndexMap.IPIMap,
370 ExpectedIpi->typeArray()))
371 fatal("codeview::mergeIdRecords failed: " + toString(std::move(Err)));
377 static bool remapTypeIndex(TypeIndex &TI, ArrayRef<TypeIndex> TypeIndexMap) {
380 if (TI.toArrayIndex() >= TypeIndexMap.size())
382 TI = TypeIndexMap[TI.toArrayIndex()];
386 static void remapTypesInSymbolRecord(ObjFile *File, SymbolKind SymKind,
387 MutableArrayRef<uint8_t> Contents,
388 const CVIndexMap &IndexMap,
389 ArrayRef<TiReference> TypeRefs) {
390 for (const TiReference &Ref : TypeRefs) {
391 unsigned ByteSize = Ref.Count * sizeof(TypeIndex);
392 if (Contents.size() < Ref.Offset + ByteSize)
393 fatal("symbol record too short");
395 // This can be an item index or a type index. Choose the appropriate map.
396 ArrayRef<TypeIndex> TypeOrItemMap = IndexMap.TPIMap;
397 bool IsItemIndex = Ref.Kind == TiRefKind::IndexRef;
398 if (IsItemIndex && IndexMap.IsTypeServerMap)
399 TypeOrItemMap = IndexMap.IPIMap;
401 MutableArrayRef<TypeIndex> TIs(
402 reinterpret_cast<TypeIndex *>(Contents.data() + Ref.Offset), Ref.Count);
403 for (TypeIndex &TI : TIs) {
404 if (!remapTypeIndex(TI, TypeOrItemMap)) {
405 log("ignoring symbol record of kind 0x" + utohexstr(SymKind) + " in " +
406 File->getName() + " with bad " + (IsItemIndex ? "item" : "type") +
407 " index 0x" + utohexstr(TI.getIndex()));
408 TI = TypeIndex(SimpleTypeKind::NotTranslated);
415 static SymbolKind symbolKind(ArrayRef<uint8_t> RecordData) {
416 const RecordPrefix *Prefix =
417 reinterpret_cast<const RecordPrefix *>(RecordData.data());
418 return static_cast<SymbolKind>(uint16_t(Prefix->RecordKind));
421 /// MSVC translates S_PROC_ID_END to S_END, and S_[LG]PROC32_ID to S_[LG]PROC32
422 static void translateIdSymbols(MutableArrayRef<uint8_t> &RecordData,
423 TypeCollection &IDTable) {
424 RecordPrefix *Prefix = reinterpret_cast<RecordPrefix *>(RecordData.data());
426 SymbolKind Kind = symbolKind(RecordData);
428 if (Kind == SymbolKind::S_PROC_ID_END) {
429 Prefix->RecordKind = SymbolKind::S_END;
433 // In an object file, GPROC32_ID has an embedded reference which refers to the
434 // single object file type index namespace. This has already been translated
435 // to the PDB file's ID stream index space, but we need to convert this to a
436 // symbol that refers to the type stream index space. So we remap again from
437 // ID index space to type index space.
438 if (Kind == SymbolKind::S_GPROC32_ID || Kind == SymbolKind::S_LPROC32_ID) {
439 SmallVector<TiReference, 1> Refs;
440 auto Content = RecordData.drop_front(sizeof(RecordPrefix));
441 CVSymbol Sym(Kind, RecordData);
442 discoverTypeIndicesInSymbol(Sym, Refs);
443 assert(Refs.size() == 1);
444 assert(Refs.front().Count == 1);
447 reinterpret_cast<TypeIndex *>(Content.data() + Refs[0].Offset);
448 // `TI` is the index of a FuncIdRecord or MemberFuncIdRecord which lives in
449 // the IPI stream, whose `FunctionType` member refers to the TPI stream.
450 // Note that LF_FUNC_ID and LF_MEMFUNC_ID have the same record layout, and
451 // in both cases we just need the second type index.
452 if (!TI->isSimple() && !TI->isNoneType()) {
453 CVType FuncIdData = IDTable.getType(*TI);
454 SmallVector<TypeIndex, 2> Indices;
455 discoverTypeIndices(FuncIdData, Indices);
456 assert(Indices.size() == 2);
460 Kind = (Kind == SymbolKind::S_GPROC32_ID) ? SymbolKind::S_GPROC32
461 : SymbolKind::S_LPROC32;
462 Prefix->RecordKind = uint16_t(Kind);
466 /// Copy the symbol record. In a PDB, symbol records must be 4 byte aligned.
467 /// The object file may not be aligned.
468 static MutableArrayRef<uint8_t> copySymbolForPdb(const CVSymbol &Sym,
469 BumpPtrAllocator &Alloc) {
470 size_t Size = alignTo(Sym.length(), alignOf(CodeViewContainer::Pdb));
471 assert(Size >= 4 && "record too short");
472 assert(Size <= MaxRecordLength && "record too long");
473 void *Mem = Alloc.Allocate(Size, 4);
475 // Copy the symbol record and zero out any padding bytes.
476 MutableArrayRef<uint8_t> NewData(reinterpret_cast<uint8_t *>(Mem), Size);
477 memcpy(NewData.data(), Sym.data().data(), Sym.length());
478 memset(NewData.data() + Sym.length(), 0, Size - Sym.length());
480 // Update the record prefix length. It should point to the beginning of the
482 auto *Prefix = reinterpret_cast<RecordPrefix *>(Mem);
483 Prefix->RecordLen = Size - 2;
487 /// Return true if this symbol opens a scope. This implies that the symbol has
488 /// "parent" and "end" fields, which contain the offset of the S_END or
489 /// S_INLINESITE_END record.
490 static bool symbolOpensScope(SymbolKind Kind) {
492 case SymbolKind::S_GPROC32:
493 case SymbolKind::S_LPROC32:
494 case SymbolKind::S_LPROC32_ID:
495 case SymbolKind::S_GPROC32_ID:
496 case SymbolKind::S_BLOCK32:
497 case SymbolKind::S_SEPCODE:
498 case SymbolKind::S_THUNK32:
499 case SymbolKind::S_INLINESITE:
500 case SymbolKind::S_INLINESITE2:
508 static bool symbolEndsScope(SymbolKind Kind) {
510 case SymbolKind::S_END:
511 case SymbolKind::S_PROC_ID_END:
512 case SymbolKind::S_INLINESITE_END:
521 ulittle32_t PtrParent;
526 ScopeRecord *OpeningRecord;
527 uint32_t ScopeOffset;
530 static void scopeStackOpen(SmallVectorImpl<SymbolScope> &Stack,
531 uint32_t CurOffset, CVSymbol &Sym) {
532 assert(symbolOpensScope(Sym.kind()));
534 S.ScopeOffset = CurOffset;
535 S.OpeningRecord = const_cast<ScopeRecord *>(
536 reinterpret_cast<const ScopeRecord *>(Sym.content().data()));
537 S.OpeningRecord->PtrParent = Stack.empty() ? 0 : Stack.back().ScopeOffset;
541 static void scopeStackClose(SmallVectorImpl<SymbolScope> &Stack,
542 uint32_t CurOffset, ObjFile *File) {
544 warn("symbol scopes are not balanced in " + File->getName());
547 SymbolScope S = Stack.pop_back_val();
548 S.OpeningRecord->PtrEnd = CurOffset;
551 static bool symbolGoesInModuleStream(const CVSymbol &Sym) {
552 switch (Sym.kind()) {
553 case SymbolKind::S_GDATA32:
554 case SymbolKind::S_CONSTANT:
555 case SymbolKind::S_UDT:
556 // We really should not be seeing S_PROCREF and S_LPROCREF in the first place
557 // since they are synthesized by the linker in response to S_GPROC32 and
558 // S_LPROC32, but if we do see them, don't put them in the module stream I
560 case SymbolKind::S_PROCREF:
561 case SymbolKind::S_LPROCREF:
563 // S_GDATA32 does not go in the module stream, but S_LDATA32 does.
564 case SymbolKind::S_LDATA32:
570 static bool symbolGoesInGlobalsStream(const CVSymbol &Sym) {
571 switch (Sym.kind()) {
572 case SymbolKind::S_CONSTANT:
573 case SymbolKind::S_GDATA32:
574 // S_LDATA32 goes in both the module stream and the globals stream.
575 case SymbolKind::S_LDATA32:
576 case SymbolKind::S_GPROC32:
577 case SymbolKind::S_LPROC32:
578 // We really should not be seeing S_PROCREF and S_LPROCREF in the first place
579 // since they are synthesized by the linker in response to S_GPROC32 and
580 // S_LPROC32, but if we do see them, copy them straight through.
581 case SymbolKind::S_PROCREF:
582 case SymbolKind::S_LPROCREF:
584 // FIXME: For now, we drop all S_UDT symbols (i.e. they don't go in the
585 // globals stream or the modules stream). These have special handling which
586 // needs more investigation before we can get right, but by putting them all
587 // into the globals stream WinDbg fails to display local variables of class
588 // types saying that it cannot find the type Foo *. So as a stopgap just to
589 // keep things working, we drop them.
590 case SymbolKind::S_UDT:
596 static void addGlobalSymbol(pdb::GSIStreamBuilder &Builder, ObjFile &File,
597 const CVSymbol &Sym) {
598 switch (Sym.kind()) {
599 case SymbolKind::S_CONSTANT:
600 case SymbolKind::S_UDT:
601 case SymbolKind::S_GDATA32:
602 case SymbolKind::S_LDATA32:
603 case SymbolKind::S_PROCREF:
604 case SymbolKind::S_LPROCREF:
605 Builder.addGlobalSymbol(Sym);
607 case SymbolKind::S_GPROC32:
608 case SymbolKind::S_LPROC32: {
609 SymbolRecordKind K = SymbolRecordKind::ProcRefSym;
610 if (Sym.kind() == SymbolKind::S_LPROC32)
611 K = SymbolRecordKind::LocalProcRef;
613 PS.Module = static_cast<uint16_t>(File.ModuleDBI->getModuleIndex());
614 // For some reason, MSVC seems to add one to this value.
616 PS.Name = getSymbolName(Sym);
618 PS.SymOffset = File.ModuleDBI->getNextSymbolOffset();
619 Builder.addGlobalSymbol(PS);
623 llvm_unreachable("Invalid symbol kind!");
627 static void mergeSymbolRecords(BumpPtrAllocator &Alloc, ObjFile *File,
628 pdb::GSIStreamBuilder &GsiBuilder,
629 const CVIndexMap &IndexMap,
630 TypeCollection &IDTable,
631 BinaryStreamRef SymData) {
632 // FIXME: Improve error recovery by warning and skipping records when
635 BinaryStreamReader Reader(SymData);
636 ExitOnErr(Reader.readArray(Syms, Reader.getLength()));
637 SmallVector<SymbolScope, 4> Scopes;
638 for (CVSymbol Sym : Syms) {
639 // Discover type index references in the record. Skip it if we don't know
641 SmallVector<TiReference, 32> TypeRefs;
642 if (!discoverTypeIndicesInSymbol(Sym, TypeRefs)) {
643 log("ignoring unknown symbol record with kind 0x" + utohexstr(Sym.kind()));
647 // Copy the symbol record so we can mutate it.
648 MutableArrayRef<uint8_t> NewData = copySymbolForPdb(Sym, Alloc);
650 // Re-map all the type index references.
651 MutableArrayRef<uint8_t> Contents =
652 NewData.drop_front(sizeof(RecordPrefix));
653 remapTypesInSymbolRecord(File, Sym.kind(), Contents, IndexMap, TypeRefs);
655 // An object file may have S_xxx_ID symbols, but these get converted to
656 // "real" symbols in a PDB.
657 translateIdSymbols(NewData, IDTable);
659 SymbolKind NewKind = symbolKind(NewData);
661 // Fill in "Parent" and "End" fields by maintaining a stack of scopes.
662 CVSymbol NewSym(NewKind, NewData);
663 if (symbolOpensScope(NewKind))
664 scopeStackOpen(Scopes, File->ModuleDBI->getNextSymbolOffset(), NewSym);
665 else if (symbolEndsScope(NewKind))
666 scopeStackClose(Scopes, File->ModuleDBI->getNextSymbolOffset(), File);
668 // Add the symbol to the globals stream if necessary. Do this before adding
669 // the symbol to the module since we may need to get the next symbol offset,
670 // and writing to the module's symbol stream will update that offset.
671 if (symbolGoesInGlobalsStream(NewSym))
672 addGlobalSymbol(GsiBuilder, *File, NewSym);
674 // Add the symbol to the module.
675 if (symbolGoesInModuleStream(NewSym))
676 File->ModuleDBI->addSymbol(NewSym);
680 // Allocate memory for a .debug$S section and relocate it.
681 static ArrayRef<uint8_t> relocateDebugChunk(BumpPtrAllocator &Alloc,
682 SectionChunk *DebugChunk) {
683 uint8_t *Buffer = Alloc.Allocate<uint8_t>(DebugChunk->getSize());
684 assert(DebugChunk->OutputSectionOff == 0 &&
685 "debug sections should not be in output sections");
686 DebugChunk->writeTo(Buffer);
687 return consumeDebugMagic(makeArrayRef(Buffer, DebugChunk->getSize()),
691 void PDBLinker::addObjFile(ObjFile *File) {
692 // Add a module descriptor for every object file. We need to put an absolute
693 // path to the object into the PDB. If this is a plain object, we make its
694 // path absolute. If it's an object in an archive, we make the archive path
696 bool InArchive = !File->ParentName.empty();
697 SmallString<128> Path = InArchive ? File->ParentName : File->getName();
698 sys::fs::make_absolute(Path);
699 sys::path::native(Path, sys::path::Style::windows);
700 StringRef Name = InArchive ? File->getName() : StringRef(Path);
702 File->ModuleDBI = &ExitOnErr(Builder.getDbiBuilder().addModuleInfo(Name));
703 File->ModuleDBI->setObjFileName(Path);
705 // Before we can process symbol substreams from .debug$S, we need to process
706 // type information, file checksums, and the string table. Add type info to
707 // the PDB first, so that we can get the map from object file type and item
708 // indices to PDB type and item indices.
709 CVIndexMap ObjectIndexMap;
710 const CVIndexMap &IndexMap = mergeDebugT(File, ObjectIndexMap);
712 // Now do all live .debug$S sections.
713 for (SectionChunk *DebugChunk : File->getDebugChunks()) {
714 if (!DebugChunk->isLive() || DebugChunk->getSectionName() != ".debug$S")
717 ArrayRef<uint8_t> RelocatedDebugContents =
718 relocateDebugChunk(Alloc, DebugChunk);
719 if (RelocatedDebugContents.empty())
722 DebugSubsectionArray Subsections;
723 BinaryStreamReader Reader(RelocatedDebugContents, support::little);
724 ExitOnErr(Reader.readArray(Subsections, RelocatedDebugContents.size()));
726 DebugStringTableSubsectionRef CVStrTab;
727 DebugChecksumsSubsectionRef Checksums;
728 for (const DebugSubsectionRecord &SS : Subsections) {
730 case DebugSubsectionKind::StringTable:
731 ExitOnErr(CVStrTab.initialize(SS.getRecordData()));
733 case DebugSubsectionKind::FileChecksums:
734 ExitOnErr(Checksums.initialize(SS.getRecordData()));
736 case DebugSubsectionKind::Lines:
737 // We can add the relocated line table directly to the PDB without
738 // modification because the file checksum offsets will stay the same.
739 File->ModuleDBI->addDebugSubsection(SS);
741 case DebugSubsectionKind::Symbols:
742 if (Config->DebugGHashes) {
743 mergeSymbolRecords(Alloc, File, Builder.getGsiBuilder(), IndexMap,
744 GlobalIDTable, SS.getRecordData());
746 mergeSymbolRecords(Alloc, File, Builder.getGsiBuilder(), IndexMap,
747 IDTable, SS.getRecordData());
751 // FIXME: Process the rest of the subsections.
756 if (Checksums.valid()) {
757 // Make a new file checksum table that refers to offsets in the PDB-wide
758 // string table. Generally the string table subsection appears after the
759 // checksum table, so we have to do this after looping over all the
761 if (!CVStrTab.valid())
762 fatal(".debug$S sections must have both a string table subsection "
763 "and a checksum subsection table or neither");
764 auto NewChecksums = make_unique<DebugChecksumsSubsection>(PDBStrTab);
765 for (FileChecksumEntry &FC : Checksums) {
766 StringRef FileName = ExitOnErr(CVStrTab.getString(FC.FileNameOffset));
767 ExitOnErr(Builder.getDbiBuilder().addModuleSourceFile(*File->ModuleDBI,
769 NewChecksums->addChecksum(FileName, FC.Kind, FC.Checksum);
771 File->ModuleDBI->addDebugSubsection(std::move(NewChecksums));
776 static PublicSym32 createPublic(Defined *Def) {
777 PublicSym32 Pub(SymbolKind::S_PUB32);
778 Pub.Name = Def->getName();
779 if (auto *D = dyn_cast<DefinedCOFF>(Def)) {
780 if (D->getCOFFSymbol().isFunctionDefinition())
781 Pub.Flags = PublicSymFlags::Function;
782 } else if (isa<DefinedImportThunk>(Def)) {
783 Pub.Flags = PublicSymFlags::Function;
786 OutputSection *OS = Def->getChunk()->getOutputSection();
787 assert(OS && "all publics should be in final image");
788 Pub.Offset = Def->getRVA() - OS->getRVA();
789 Pub.Segment = OS->SectionIndex;
793 // Add all object files to the PDB. Merge .debug$T sections into IpiData and
795 void PDBLinker::addObjectsToPDB() {
796 for (ObjFile *File : ObjFile::Instances)
799 Builder.getStringTableBuilder().setStrings(PDBStrTab);
801 // Construct TPI and IPI stream contents.
802 if (Config->DebugGHashes) {
803 addTypeInfo(Builder.getTpiBuilder(), GlobalTypeTable);
804 addTypeInfo(Builder.getIpiBuilder(), GlobalIDTable);
806 addTypeInfo(Builder.getTpiBuilder(), TypeTable);
807 addTypeInfo(Builder.getIpiBuilder(), IDTable);
810 // Compute the public and global symbols.
811 auto &GsiBuilder = Builder.getGsiBuilder();
812 std::vector<PublicSym32> Publics;
813 Symtab->forEachSymbol([&Publics](Symbol *S) {
814 // Only emit defined, live symbols that have a chunk.
815 auto *Def = dyn_cast<Defined>(S);
816 if (Def && Def->isLive() && Def->getChunk())
817 Publics.push_back(createPublic(Def));
820 if (!Publics.empty()) {
821 // Sort the public symbols and add them to the stream.
822 std::sort(Publics.begin(), Publics.end(),
823 [](const PublicSym32 &L, const PublicSym32 &R) {
824 return L.Name < R.Name;
826 for (const PublicSym32 &Pub : Publics)
827 GsiBuilder.addPublicSymbol(Pub);
831 static void addCommonLinkerModuleSymbols(StringRef Path,
832 pdb::DbiModuleDescriptorBuilder &Mod,
833 BumpPtrAllocator &Allocator) {
834 ObjNameSym ONS(SymbolRecordKind::ObjNameSym);
835 Compile3Sym CS(SymbolRecordKind::Compile3Sym);
836 EnvBlockSym EBS(SymbolRecordKind::EnvBlockSym);
838 ONS.Name = "* Linker *";
841 CS.Machine = Config->is64() ? CPUType::X64 : CPUType::Intel80386;
842 // Interestingly, if we set the string to 0.0.0.0, then when trying to view
843 // local variables WinDbg emits an error that private symbols are not present.
844 // By setting this to a valid MSVC linker version string, local variables are
845 // displayed properly. As such, even though it is not representative of
846 // LLVM's version information, we need this for compatibility.
847 CS.Flags = CompileSym3Flags::None;
848 CS.VersionBackendBuild = 25019;
849 CS.VersionBackendMajor = 14;
850 CS.VersionBackendMinor = 10;
851 CS.VersionBackendQFE = 0;
853 // MSVC also sets the frontend to 0.0.0.0 since this is specifically for the
854 // linker module (which is by definition a backend), so we don't need to do
855 // anything here. Also, it seems we can use "LLVM Linker" for the linker name
856 // without any problems. Only the backend version has to be hardcoded to a
858 CS.VersionFrontendBuild = 0;
859 CS.VersionFrontendMajor = 0;
860 CS.VersionFrontendMinor = 0;
861 CS.VersionFrontendQFE = 0;
862 CS.Version = "LLVM Linker";
863 CS.setLanguage(SourceLanguage::Link);
865 ArrayRef<StringRef> Args = makeArrayRef(Config->Argv).drop_front();
866 std::string ArgStr = llvm::join(Args, " ");
867 EBS.Fields.push_back("cwd");
869 sys::fs::current_path(cwd);
870 EBS.Fields.push_back(cwd);
871 EBS.Fields.push_back("exe");
872 SmallString<64> exe = Config->Argv[0];
873 llvm::sys::fs::make_absolute(exe);
874 EBS.Fields.push_back(exe);
875 EBS.Fields.push_back("pdb");
876 EBS.Fields.push_back(Path);
877 EBS.Fields.push_back("cmd");
878 EBS.Fields.push_back(ArgStr);
879 Mod.addSymbol(codeview::SymbolSerializer::writeOneSymbol(
880 ONS, Allocator, CodeViewContainer::Pdb));
881 Mod.addSymbol(codeview::SymbolSerializer::writeOneSymbol(
882 CS, Allocator, CodeViewContainer::Pdb));
883 Mod.addSymbol(codeview::SymbolSerializer::writeOneSymbol(
884 EBS, Allocator, CodeViewContainer::Pdb));
887 static void addLinkerModuleSectionSymbol(pdb::DbiModuleDescriptorBuilder &Mod,
889 BumpPtrAllocator &Allocator) {
890 SectionSym Sym(SymbolRecordKind::SectionSym);
891 Sym.Alignment = 12; // 2^12 = 4KB
892 Sym.Characteristics = OS.getCharacteristics();
893 Sym.Length = OS.getVirtualSize();
894 Sym.Name = OS.getName();
895 Sym.Rva = OS.getRVA();
896 Sym.SectionNumber = OS.SectionIndex;
897 Mod.addSymbol(codeview::SymbolSerializer::writeOneSymbol(
898 Sym, Allocator, CodeViewContainer::Pdb));
901 // Creates a PDB file.
902 void coff::createPDB(SymbolTable *Symtab,
903 ArrayRef<OutputSection *> OutputSections,
904 ArrayRef<uint8_t> SectionTable,
905 const llvm::codeview::DebugInfo &BuildId) {
906 PDBLinker PDB(Symtab);
907 PDB.initialize(BuildId);
908 PDB.addObjectsToPDB();
909 PDB.addSections(OutputSections, SectionTable);
913 void PDBLinker::initialize(const llvm::codeview::DebugInfo &BuildId) {
914 ExitOnErr(Builder.initialize(4096)); // 4096 is blocksize
916 // Create streams in MSF for predefined streams, namely
917 // PDB, TPI, DBI and IPI.
918 for (int I = 0; I < (int)pdb::kSpecialStreamCount; ++I)
919 ExitOnErr(Builder.getMsfBuilder().addStream(0));
921 // Add an Info stream.
922 auto &InfoBuilder = Builder.getInfoBuilder();
923 InfoBuilder.setAge(BuildId.PDB70.Age);
926 memcpy(&uuid, &BuildId.PDB70.Signature, sizeof(uuid));
927 InfoBuilder.setGuid(uuid);
928 InfoBuilder.setSignature(time(nullptr));
929 InfoBuilder.setVersion(pdb::PdbRaw_ImplVer::PdbImplVC70);
931 // Add an empty DBI stream.
932 pdb::DbiStreamBuilder &DbiBuilder = Builder.getDbiBuilder();
933 DbiBuilder.setAge(BuildId.PDB70.Age);
934 DbiBuilder.setVersionHeader(pdb::PdbDbiV70);
935 ExitOnErr(DbiBuilder.addDbgStream(pdb::DbgHeaderType::NewFPO, {}));
938 void PDBLinker::addSectionContrib(pdb::DbiModuleDescriptorBuilder &LinkerModule,
939 OutputSection *OS, Chunk *C) {
940 pdb::SectionContrib SC;
941 memset(&SC, 0, sizeof(SC));
942 SC.ISect = OS->SectionIndex;
943 SC.Off = C->getRVA() - OS->getRVA();
944 SC.Size = C->getSize();
945 if (auto *SecChunk = dyn_cast<SectionChunk>(C)) {
946 SC.Characteristics = SecChunk->Header->Characteristics;
947 SC.Imod = SecChunk->File->ModuleDBI->getModuleIndex();
948 ArrayRef<uint8_t> Contents = SecChunk->getContents();
950 ArrayRef<char> CharContents = makeArrayRef(
951 reinterpret_cast<const char *>(Contents.data()), Contents.size());
952 CRC.update(CharContents);
953 SC.DataCrc = CRC.getCRC();
955 SC.Characteristics = OS->getCharacteristics();
956 // FIXME: When we start creating DBI for import libraries, use those here.
957 SC.Imod = LinkerModule.getModuleIndex();
959 SC.RelocCrc = 0; // FIXME
960 Builder.getDbiBuilder().addSectionContrib(SC);
963 void PDBLinker::addSections(ArrayRef<OutputSection *> OutputSections,
964 ArrayRef<uint8_t> SectionTable) {
965 // It's not entirely clear what this is, but the * Linker * module uses it.
966 pdb::DbiStreamBuilder &DbiBuilder = Builder.getDbiBuilder();
967 NativePath = Config->PDBPath;
968 sys::fs::make_absolute(NativePath);
969 sys::path::native(NativePath, sys::path::Style::windows);
970 uint32_t PdbFilePathNI = DbiBuilder.addECName(NativePath);
971 auto &LinkerModule = ExitOnErr(DbiBuilder.addModuleInfo("* Linker *"));
972 LinkerModule.setPdbFilePathNI(PdbFilePathNI);
973 addCommonLinkerModuleSymbols(NativePath, LinkerModule, Alloc);
975 // Add section contributions. They must be ordered by ascending RVA.
976 for (OutputSection *OS : OutputSections) {
977 addLinkerModuleSectionSymbol(LinkerModule, *OS, Alloc);
978 for (Chunk *C : OS->getChunks())
979 addSectionContrib(LinkerModule, OS, C);
982 // Add Section Map stream.
983 ArrayRef<object::coff_section> Sections = {
984 (const object::coff_section *)SectionTable.data(),
985 SectionTable.size() / sizeof(object::coff_section)};
986 SectionMap = pdb::DbiStreamBuilder::createSectionMap(Sections);
987 DbiBuilder.setSectionMap(SectionMap);
989 // Add COFF section header stream.
991 DbiBuilder.addDbgStream(pdb::DbgHeaderType::SectionHdr, SectionTable));
994 void PDBLinker::commit() {
996 ExitOnErr(Builder.commit(Config->PDBPath));