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llvm-project/lld/COFF/PDB.cpp

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//===- PDB.cpp ------------------------------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "PDB.h"
#include "Chunks.h"
#include "Config.h"
#include "Error.h"
#include "SymbolTable.h"
#include "Symbols.h"
#include "llvm/DebugInfo/CodeView/CVDebugRecord.h"
#include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
#include "llvm/DebugInfo/CodeView/DebugSubsectionRecord.h"
#include "llvm/DebugInfo/CodeView/DebugSubsectionVisitor.h"
#include "llvm/DebugInfo/CodeView/LazyRandomTypeCollection.h"
#include "llvm/DebugInfo/CodeView/TypeDumpVisitor.h"
#include "llvm/DebugInfo/CodeView/TypeIndexDiscovery.h"
#include "llvm/DebugInfo/CodeView/TypeStreamMerger.h"
#include "llvm/DebugInfo/CodeView/TypeTableBuilder.h"
#include "llvm/DebugInfo/MSF/MSFBuilder.h"
#include "llvm/DebugInfo/MSF/MSFCommon.h"
#include "llvm/DebugInfo/PDB/Native/DbiStream.h"
#include "llvm/DebugInfo/PDB/Native/DbiStreamBuilder.h"
#include "llvm/DebugInfo/PDB/Native/InfoStream.h"
#include "llvm/DebugInfo/PDB/Native/InfoStreamBuilder.h"
#include "llvm/DebugInfo/PDB/Native/PDBFile.h"
#include "llvm/DebugInfo/PDB/Native/PDBFileBuilder.h"
#include "llvm/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.h"
#include "llvm/DebugInfo/PDB/Native/PDBStringTableBuilder.h"
#include "llvm/DebugInfo/PDB/Native/PDBTypeServerHandler.h"
#include "llvm/DebugInfo/PDB/Native/TpiStream.h"
#include "llvm/DebugInfo/PDB/Native/TpiStreamBuilder.h"
#include "llvm/Object/COFF.h"
#include "llvm/Support/BinaryByteStream.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/FileOutputBuffer.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;
// Returns a list of all SectionChunks.
static void addSectionContribs(SymbolTable *Symtab, pdb::DbiStreamBuilder &DbiBuilder) {
for (Chunk *C : Symtab->getChunks())
if (auto *SC = dyn_cast<SectionChunk>(C))
DbiBuilder.addSectionContrib(SC->File->ModuleDBI, SC->Header);
}
static SectionChunk *findByName(std::vector<SectionChunk *> &Sections,
StringRef Name) {
for (SectionChunk *C : Sections)
if (C->getSectionName() == Name)
return C;
return nullptr;
}
static ArrayRef<uint8_t> consumeDebugMagic(ArrayRef<uint8_t> Data,
StringRef SecName) {
// First 4 bytes are section magic.
if (Data.size() < 4)
fatal(SecName + " too short");
if (support::endian::read32le(Data.data()) != COFF::DEBUG_SECTION_MAGIC)
fatal(SecName + " has an invalid magic");
return Data.slice(4);
}
static ArrayRef<uint8_t> getDebugSection(ObjectFile *File, StringRef SecName) {
if (SectionChunk *Sec = findByName(File->getDebugChunks(), SecName))
return consumeDebugMagic(Sec->getContents(), SecName);
return {};
}
static void addTypeInfo(pdb::TpiStreamBuilder &TpiBuilder,
TypeTableBuilder &TypeTable) {
// Start the TPI or IPI stream header.
TpiBuilder.setVersionHeader(pdb::PdbTpiV80);
// Flatten the in memory type table.
TypeTable.ForEachRecord([&](TypeIndex TI, ArrayRef<uint8_t> Rec) {
// FIXME: Hash types.
TpiBuilder.addTypeRecord(Rec, None);
});
}
static void mergeDebugT(ObjectFile *File,
TypeTableBuilder &IDTable,
TypeTableBuilder &TypeTable,
SmallVectorImpl<TypeIndex> &TypeIndexMap,
pdb::PDBTypeServerHandler &Handler) {
ArrayRef<uint8_t> Data = getDebugSection(File, ".debug$T");
if (Data.empty())
return;
BinaryByteStream Stream(Data, support::little);
CVTypeArray Types;
BinaryStreamReader Reader(Stream);
Handler.addSearchPath(sys::path::parent_path(File->getName()));
if (auto EC = Reader.readArray(Types, Reader.getLength()))
fatal(EC, "Reader::readArray failed");
if (auto Err = mergeTypeAndIdRecords(IDTable, TypeTable,
TypeIndexMap, &Handler, Types))
fatal(Err, "codeview::mergeTypeStreams failed");
}
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 bool remapTypesInSymbolRecord(ObjectFile *File,
MutableArrayRef<uint8_t> Contents,
ArrayRef<TypeIndex> TypeIndexMap,
ArrayRef<TiReference> TypeRefs) {
for (const TiReference &Ref : TypeRefs) {
unsigned ByteSize = Ref.Count * sizeof(TypeIndex);
if (Contents.size() < Ref.Offset + ByteSize) {
log("ignoring short symbol record");
return false;
}
MutableArrayRef<TypeIndex> TIs(
reinterpret_cast<TypeIndex *>(Contents.data() + Ref.Offset), Ref.Count);
for (TypeIndex &TI : TIs)
if (!remapTypeIndex(TI, TypeIndexMap)) {
log("ignoring symbol record in " + File->getName() +
" with bad type index 0x" + utohexstr(TI.getIndex()));
return false;
}
}
return true;
}
/// MSVC translates S_PROC_ID_END to S_END.
uint16_t canonicalizeSymbolKind(SymbolKind Kind) {
if (Kind == SymbolKind::S_PROC_ID_END)
return SymbolKind::S_END;
return 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> copySymbolForPdb(const CVSymbol &Sym,
BumpPtrAllocator &Alloc) {
size_t Size = alignTo(Sym.length(), alignOf(CodeViewContainer::Pdb));
assert(Size >= 4 && "record too short");
assert(Size <= MaxRecordLength && "record too long");
void *Mem = Alloc.Allocate(Size, 4);
// Copy the symbol record and zero out any padding bytes.
MutableArrayRef<uint8_t> NewData(reinterpret_cast<uint8_t *>(Mem), Size);
memcpy(NewData.data(), Sym.data().data(), Sym.length());
memset(NewData.data() + Sym.length(), 0, Size - Sym.length());
// Update the record prefix length. It should point to the beginning of the
// next record. MSVC does some canonicalization of the record kind, so we do
// that as well.
auto *Prefix = reinterpret_cast<RecordPrefix *>(Mem);
Prefix->RecordKind = canonicalizeSymbolKind(Sym.kind());
Prefix->RecordLen = Size - 2;
return NewData;
}
/// Return true if this symbol opens a scope. This implies that the symbol has
/// "parent" and "end" fields, which contain the offset of the S_END or
/// S_INLINESITE_END record.
static bool symbolOpensScope(SymbolKind Kind) {
switch (Kind) {
case SymbolKind::S_GPROC32:
case SymbolKind::S_LPROC32:
case SymbolKind::S_LPROC32_ID:
case SymbolKind::S_GPROC32_ID:
case SymbolKind::S_BLOCK32:
case SymbolKind::S_SEPCODE:
case SymbolKind::S_THUNK32:
case SymbolKind::S_INLINESITE:
case SymbolKind::S_INLINESITE2:
return true;
default:
break;
}
return false;
}
static bool symbolEndsScope(SymbolKind Kind) {
switch (Kind) {
case SymbolKind::S_END:
case SymbolKind::S_PROC_ID_END:
case SymbolKind::S_INLINESITE_END:
return true;
default:
break;
}
return false;
}
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, ObjectFile *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 void mergeSymbolRecords(BumpPtrAllocator &Alloc, ObjectFile *File,
ArrayRef<TypeIndex> TypeIndexMap,
BinaryStreamRef SymData) {
// FIXME: Improve error recovery by warning and skipping records when
// possible.
CVSymbolArray Syms;
BinaryStreamReader Reader(SymData);
ExitOnErr(Reader.readArray(Syms, Reader.getLength()));
SmallVector<SymbolScope, 4> Scopes;
for (const CVSymbol &Sym : Syms) {
// Discover type index references in the record. Skip it if we don't know
// where they are.
SmallVector<TiReference, 32> TypeRefs;
if (!discoverTypeIndices(Sym, TypeRefs)) {
log("ignoring unknown symbol record with kind 0x" + utohexstr(Sym.kind()));
continue;
}
// Copy the symbol record so we can mutate it.
MutableArrayRef<uint8_t> NewData = copySymbolForPdb(Sym, Alloc);
// Re-map all the type index references.
MutableArrayRef<uint8_t> Contents =
NewData.drop_front(sizeof(RecordPrefix));
if (!remapTypesInSymbolRecord(File, Contents, TypeIndexMap, TypeRefs))
continue;
// Fill in "Parent" and "End" fields by maintaining a stack of scopes.
CVSymbol NewSym(Sym.kind(), NewData);
if (symbolOpensScope(Sym.kind()))
scopeStackOpen(Scopes, File->ModuleDBI->getNextSymbolOffset(), NewSym);
else if (symbolEndsScope(Sym.kind()))
scopeStackClose(Scopes, File->ModuleDBI->getNextSymbolOffset(), File);
// Add the symbol to the module.
File->ModuleDBI->addSymbol(NewSym);
}
}
// Allocate memory for a .debug$S section and relocate it.
static ArrayRef<uint8_t> relocateDebugChunk(BumpPtrAllocator &Alloc,
SectionChunk *DebugChunk) {
uint8_t *Buffer = Alloc.Allocate<uint8_t>(DebugChunk->getSize());
assert(DebugChunk->OutputSectionOff == 0 &&
"debug sections should not be in output sections");
DebugChunk->writeTo(Buffer);
return consumeDebugMagic(makeArrayRef(Buffer, DebugChunk->getSize()),
".debug$S");
}
// Add all object files to the PDB. Merge .debug$T sections into IpiData and
// TpiData.
static void addObjectsToPDB(BumpPtrAllocator &Alloc, SymbolTable *Symtab,
pdb::PDBFileBuilder &Builder,
TypeTableBuilder &TypeTable,
TypeTableBuilder &IDTable) {
// Follow type servers. If the same type server is encountered more than
// once for this instance of `PDBTypeServerHandler` (for example if many
// object files reference the same TypeServer), the types from the
// TypeServer will only be visited once.
pdb::PDBTypeServerHandler Handler;
// PDBs use a single global string table for filenames in the file checksum
// table.
auto PDBStrTab = std::make_shared<DebugStringTableSubsection>();
// Visit all .debug$T sections to add them to Builder.
for (ObjectFile *File : Symtab->ObjectFiles) {
// Add a module descriptor for every object file. We need to put an absolute
// path to the object into the PDB. If this is a plain object, we make its
// path absolute. If it's an object in an archive, we make the archive path
// absolute.
bool InArchive = !File->ParentName.empty();
SmallString<128> Path = InArchive ? File->ParentName : File->getName();
sys::fs::make_absolute(Path);
StringRef Name = InArchive ? File->getName() : StringRef(Path);
File->ModuleDBI = &ExitOnErr(Builder.getDbiBuilder().addModuleInfo(Name));
File->ModuleDBI->setObjFileName(Path);
// Before we can process symbol substreams from .debug$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.
SmallVector<TypeIndex, 128> TypeIndexMap;
mergeDebugT(File, IDTable, TypeTable, TypeIndexMap, Handler);
// Now do all line info.
for (SectionChunk *DebugChunk : File->getDebugChunks()) {
if (!DebugChunk->isLive() || DebugChunk->getSectionName() != ".debug$S")
continue;
ArrayRef<uint8_t> RelocatedDebugContents =
relocateDebugChunk(Alloc, DebugChunk);
if (RelocatedDebugContents.empty())
continue;
DebugSubsectionArray Subsections;
BinaryStreamReader Reader(RelocatedDebugContents, support::little);
ExitOnErr(Reader.readArray(Subsections, RelocatedDebugContents.size()));
DebugStringTableSubsectionRef CVStrTab;
DebugChecksumsSubsectionRef Checksums;
for (const DebugSubsectionRecord &SS : Subsections) {
switch (SS.kind()) {
case DebugSubsectionKind::StringTable:
ExitOnErr(CVStrTab.initialize(SS.getRecordData()));
break;
case DebugSubsectionKind::FileChecksums:
ExitOnErr(Checksums.initialize(SS.getRecordData()));
break;
case DebugSubsectionKind::Lines:
// We can add the relocated line table directly to the PDB without
// modification because the file checksum offsets will stay the same.
File->ModuleDBI->addDebugSubsection(SS);
break;
case DebugSubsectionKind::Symbols:
mergeSymbolRecords(Alloc, File, TypeIndexMap, SS.getRecordData());
break;
default:
// FIXME: Process the rest of the subsections.
break;
}
}
if (Checksums.valid()) {
// Make a new file checksum table that refers to offsets in the PDB-wide
// string table. Generally the string table subsection appears after the
// checksum table, so we have to do this after looping over all the
// subsections.
if (!CVStrTab.valid())
fatal(".debug$S sections must have both a string table subsection "
"and a checksum subsection table or neither");
auto NewChecksums =
make_unique<DebugChecksumsSubsection>(*PDBStrTab);
for (FileChecksumEntry &FC : Checksums) {
StringRef FileName = ExitOnErr(CVStrTab.getString(FC.FileNameOffset));
ExitOnErr(Builder.getDbiBuilder().addModuleSourceFile(
*File->ModuleDBI, FileName));
NewChecksums->addChecksum(FileName, FC.Kind, FC.Checksum);
}
File->ModuleDBI->addDebugSubsection(std::move(NewChecksums));
}
}
}
Builder.getStringTableBuilder().setStrings(*PDBStrTab);
// Construct TPI stream contents.
addTypeInfo(Builder.getTpiBuilder(), TypeTable);
// Construct IPI stream contents.
addTypeInfo(Builder.getIpiBuilder(), IDTable);
}
// Creates a PDB file.
void coff::createPDB(StringRef Path, SymbolTable *Symtab,
ArrayRef<uint8_t> SectionTable,
const llvm::codeview::DebugInfo *DI) {
BumpPtrAllocator Alloc;
pdb::PDBFileBuilder Builder(Alloc);
ExitOnErr(Builder.initialize(4096)); // 4096 is blocksize
// 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.setAge(DI ? DI->PDB70.Age : 0);
llvm::SmallString<128> NativePath(Path.begin(), Path.end());
llvm::sys::fs::make_absolute(NativePath);
llvm::sys::path::native(NativePath);
pdb::PDB_UniqueId uuid{};
if (DI)
memcpy(&uuid, &DI->PDB70.Signature, sizeof(uuid));
InfoBuilder.setGuid(uuid);
// Should be the current time, but set 0 for reproducibilty.
InfoBuilder.setSignature(0);
InfoBuilder.setVersion(pdb::PdbRaw_ImplVer::PdbImplVC70);
// Add an empty DBI stream.
pdb::DbiStreamBuilder &DbiBuilder = Builder.getDbiBuilder();
DbiBuilder.setVersionHeader(pdb::PdbDbiV110);
// It's not entirely clear what this is, but the * Linker * module uses it.
uint32_t PdbFilePathNI = DbiBuilder.addECName(NativePath);
TypeTableBuilder TypeTable(BAlloc);
TypeTableBuilder IDTable(BAlloc);
addObjectsToPDB(Alloc, Symtab, Builder, TypeTable, IDTable);
// Add Section Contributions.
addSectionContribs(Symtab, DbiBuilder);
// Add Section Map stream.
ArrayRef<object::coff_section> Sections = {
(const object::coff_section *)SectionTable.data(),
SectionTable.size() / sizeof(object::coff_section)};
std::vector<pdb::SecMapEntry> SectionMap =
pdb::DbiStreamBuilder::createSectionMap(Sections);
DbiBuilder.setSectionMap(SectionMap);
auto &LinkerModule = ExitOnErr(DbiBuilder.addModuleInfo("* Linker *"));
LinkerModule.setPdbFilePathNI(PdbFilePathNI);
// Add COFF section header stream.
ExitOnErr(
DbiBuilder.addDbgStream(pdb::DbgHeaderType::SectionHdr, SectionTable));
// Write to a file.
ExitOnErr(Builder.commit(Path));
}
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