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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 "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/TypeIndexDiscovery.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/CRC.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/FormatAdapters.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/ScopedPrinter.h"
#include <memory>
using namespace llvm;
using namespace llvm::codeview;
using namespace lld;
using namespace lld::coff;
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 publicsLayoutTimer("Publics 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)
: symtab(symtab), builder(bAlloc), tMerger(bAlloc) {
// 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();
/// Add named streams specified on the command line.
void addNamedStreams();
/// Link CodeView from each object file in the symbol table into the PDB.
void addObjectsToPDB();
/// Add every live, defined public symbol to the PDB.
void addPublicsToPDB();
/// 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 addDebug(TpiSource *source);
const CVIndexMap *mergeTypeRecords(TpiSource *source, CVIndexMap *localMap);
void addDebugSymbols(ObjFile *file, const CVIndexMap *indexMap);
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:
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;
// 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);
}
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);
});
}
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);
ArrayRef<uint8_t> tiBuf = funcIdData.data().slice(8, 4);
assert(tiBuf.size() == 4 && "corrupt LF_[MEM]FUNC_ID record");
*ti = *reinterpret_cast<const TypeIndex *>(tiBuf.data());
}
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:
case SymbolKind::S_GTHREAD32:
// 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:
case SymbolKind::S_LTHREAD32:
default:
return true;
}
}
static bool symbolGoesInGlobalsStream(const CVSymbol &sym,
bool isFunctionScope) {
switch (sym.kind()) {
case SymbolKind::S_CONSTANT:
case SymbolKind::S_GDATA32:
case SymbolKind::S_GTHREAD32:
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;
// Records that go in the globals stream, unless they are function-local.
case SymbolKind::S_UDT:
case SymbolKind::S_LDATA32:
case SymbolKind::S_LTHREAD32:
return !isFunctionScope;
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_GTHREAD32:
case SymbolKind::S_LTHREAD32:
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 =
bAlloc.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(SectionChunk &debugChunk) {
uint8_t *buffer = bAlloc.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);
crc.update(contents);
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(debugS), debugS.getSectionName());
BinaryStreamReader reader(relocatedDebugContents, support::little);
exitOnErr(reader.readArray(subsections, relocatedDebugContents.size()));
// If there is no index map, use an empty one.
CVIndexMap tempIndexMap;
if (!indexMap)
indexMap = &tempIndexMap;
for (const DebugSubsectionRecord &ss : subsections) {
// Ignore subsections with the 'ignore' bit. Some versions of the Visual C++
// runtime have subsections with this bit set.
if (uint32_t(ss.kind()) & codeview::SubsectionIgnoreFlag)
continue;
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$S subsection kind 0x" +
utohexstr(uint32_t(ss.kind())) + " in file " + toString(&file));
break;
}
}
}
static Expected<StringRef>
getFileName(const DebugStringTableSubsectionRef &strings,
const DebugChecksumsSubsectionRef &checksums, uint32_t fileID) {
auto iter = checksums.getArray().at(fileID);
if (iter == checksums.getArray().end())
return make_error<CodeViewError>(cv_error_code::no_records);
uint32_t offset = iter->FileNameOffset;
return strings.getString(offset);
}
std::shared_ptr<DebugInlineeLinesSubsection>
DebugSHandler::mergeInlineeLines(DebugChecksumsSubsection *newChecksums) {
auto newInlineeLines = std::make_shared<DebugInlineeLinesSubsection>(
*newChecksums, inlineeLines.hasExtraFiles());
for (const InlineeSourceLine &line : inlineeLines) {
TypeIndex inlinee = line.Header->Inlinee;
uint32_t fileID = line.Header->FileID;
uint32_t sourceLine = line.Header->SourceLineNum;
ArrayRef<TypeIndex> typeOrItemMap =
indexMap->isTypeServerMap ? indexMap->ipiMap : indexMap->tpiMap;
if (!remapTypeIndex(inlinee, typeOrItemMap)) {
log("ignoring inlinee line record in " + file.getName() +
" with bad inlinee index 0x" + utohexstr(inlinee.getIndex()));
continue;
}
SmallString<128> filename =
exitOnErr(getFileName(cvStrTab, checksums, fileID));
pdbMakeAbsolute(filename);
newInlineeLines->addInlineSite(inlinee, filename, sourceLine);
if (inlineeLines.hasExtraFiles()) {
for (uint32_t extraFileId : line.ExtraFiles) {
filename = exitOnErr(getFileName(cvStrTab, checksums, extraFileId));
pdbMakeAbsolute(filename);
newInlineeLines->addExtraFile(filename);
}
}
}
return newInlineeLines;
}
void DebugSHandler::finish() {
pdb::DbiStreamBuilder &dbiBuilder = linker.builder.getDbiBuilder();
// We should have seen all debug subsections across the entire object file now
// which means that if a StringTable subsection and Checksums subsection were
// present, now is the time to handle them.
if (!cvStrTab.valid()) {
if (checksums.valid())
fatal(".debug$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 = std::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));
}
static void warnUnusable(InputFile *f, Error e) {
if (!config->warnDebugInfoUnusable) {
consumeError(std::move(e));
return;
}
auto msg = "Cannot use debug info for '" + toString(f) + "' [LNK4099]";
if (e)
warn(msg + "\n>>> failed to load reference " + toString(std::move(e)));
else
warn(msg);
}
const CVIndexMap *PDBLinker::mergeTypeRecords(TpiSource *source,
CVIndexMap *localMap) {
ScopedTimer t(typeMergingTimer);
// Before we can process symbol substreams from .debug$S, we need to process
// type information, file checksums, and the string table. Add type info to
// the PDB first, so that we can get the map from object file type and item
// indices to PDB type and item indices.
Expected<const CVIndexMap *> r = source->mergeDebugT(&tMerger, localMap);
// If the .debug$T sections fail to merge, assume there is no debug info.
if (!r) {
warnUnusable(source->file, r.takeError());
return nullptr;
}
return *r;
}
void PDBLinker::addDebugSymbols(ObjFile *file, const CVIndexMap *indexMap) {
ScopedTimer t(symbolMergingTimer);
pdb::DbiStreamBuilder &dbiBuilder = builder.getDbiBuilder();
DebugSHandler dsh(*this, *file, indexMap);
// 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(*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, ObjFile *file) {
pdb::DbiStreamBuilder &dbiBuilder = builder.getDbiBuilder();
SmallString<128> objName;
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;
}
}
void PDBLinker::addDebug(TpiSource *source) {
CVIndexMap localMap;
const CVIndexMap *indexMap = mergeTypeRecords(source, &localMap);
if (source->kind == TpiSource::PDB)
return; // No symbols in TypeServer PDBs
addDebugSymbols(source->file, indexMap);
}
static pdb::BulkPublic createPublic(Defined *def) {
pdb::BulkPublic pub;
pub.Name = def->getName().data();
pub.NameLen = def->getName().size();
PublicSymFlags flags = PublicSymFlags::None;
if (auto *d = dyn_cast<DefinedCOFF>(def)) {
if (d->getCOFFSymbol().isFunctionDefinition())
flags = PublicSymFlags::Function;
} else if (isa<DefinedImportThunk>(def)) {
flags = PublicSymFlags::Function;
}
pub.Flags = static_cast<uint16_t>(flags);
OutputSection *os = def->getChunk()->getOutputSection();
assert(os && "all publics should be in final image");
pub.Offset = def->getRVA() - os->getRVA();
pub.U.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);
// Create module descriptors
for_each(ObjFile::instances,
[&](ObjFile *obj) { createModuleDBI(builder, obj); });
// Merge OBJs that do not have debug types
for_each(ObjFile::instances, [&](ObjFile *obj) {
if (obj->debugTypesObj)
return;
// Even if there're no types, still merge non-symbol .Debug$S and .Debug$F
// sections
addDebugSymbols(obj, nullptr);
});
// Merge dependencies
TpiSource::forEachSource([&](TpiSource *source) {
if (source->isDependency())
addDebug(source);
});
// Merge regular and dependent OBJs
TpiSource::forEachSource([&](TpiSource *source) {
if (!source->isDependency())
addDebug(source);
});
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();
}
void PDBLinker::addPublicsToPDB() {
ScopedTimer t3(publicsLayoutTimer);
// Compute the public symbols.
auto &gsiBuilder = builder.getGsiBuilder();
std::vector<pdb::BulkPublic> publics;
symtab->forEachSymbol([&publics](Symbol *s) {
// Only emit external, defined, live symbols that have a chunk. Static,
// non-external symbols do not appear in the symbol table.
auto *def = dyn_cast<Defined>(s);
if (def && def->isLive() && def->getChunk())
publics.push_back(createPublic(def));
});
if (!publics.empty()) {
publicSymbols = publics.size();
gsiBuilder.addPublicSymbols(std::move(publics));
}
}
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(TpiSource::countTypeServerPDBs(), "PDB type server dependencies");
print(TpiSource::countPrecompObjs(), "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");
auto printLargeInputTypeRecs = [&](StringRef name,
ArrayRef<uint32_t> recCounts,
TypeCollection &records) {
// Figure out which type indices were responsible for the most duplicate
// bytes in the input files. These should be frequently emitted LF_CLASS and
// LF_FIELDLIST records.
struct TypeSizeInfo {
uint32_t typeSize;
uint32_t dupCount;
TypeIndex typeIndex;
uint64_t totalInputSize() const { return uint64_t(dupCount) * typeSize; }
bool operator<(const TypeSizeInfo &rhs) const {
if (totalInputSize() == rhs.totalInputSize())
return typeIndex < rhs.typeIndex;
return totalInputSize() < rhs.totalInputSize();
}
};
SmallVector<TypeSizeInfo, 0> tsis;
for (auto e : enumerate(recCounts)) {
TypeIndex typeIndex = TypeIndex::fromArrayIndex(e.index());
uint32_t typeSize = records.getType(typeIndex).length();
uint32_t dupCount = e.value();
tsis.push_back({typeSize, dupCount, typeIndex});
}
if (!tsis.empty()) {
stream << "\nTop 10 types responsible for the most " << name
<< " input:\n";
stream << " index total bytes count size\n";
llvm::sort(tsis);
unsigned i = 0;
for (const auto &tsi : reverse(tsis)) {
stream << formatv(" {0,10:X}: {1,14:N} = {2,5:N} * {3,6:N}\n",
tsi.typeIndex.getIndex(), tsi.totalInputSize(),
tsi.dupCount, tsi.typeSize);
if (++i >= 10)
break;
}
stream
<< "Run llvm-pdbutil to print details about a particular record:\n";
stream << formatv("llvm-pdbutil dump -{0}s -{0}-index {1:X} {2}\n",
(name == "TPI" ? "type" : "id"),
tsis.back().typeIndex.getIndex(), config->pdbPath);
}
};
printLargeInputTypeRecs("TPI", tMerger.tpiCounts, tMerger.getTypeTable());
printLargeInputTypeRecs("IPI", tMerger.ipiCounts, tMerger.getIDTable());
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));
}
}
void PDBLinker::addNamedStreams() {
for (const auto &streamFile : config->namedStreams) {
const StringRef stream = streamFile.getKey(), file = streamFile.getValue();
ErrorOr<std::unique_ptr<MemoryBuffer>> dataOrErr =
MemoryBuffer::getFile(file);
if (!dataOrErr) {
warn("Cannot open input file: " + file);
continue;
}
exitOnErr(builder.addNamedStream(stream, (*dataOrErr)->getBuffer()));
}
}
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(std::string(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) {
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, bAlloc, CodeViewContainer::Pdb));
mod.addSymbol(codeview::SymbolSerializer::writeOneSymbol(
cs, bAlloc, CodeViewContainer::Pdb));
mod.addSymbol(codeview::SymbolSerializer::writeOneSymbol(
ebs, bAlloc, CodeViewContainer::Pdb));
}
static void addLinkerModuleCoffGroup(PartialSection *sec,
pdb::DbiModuleDescriptorBuilder &mod,
OutputSection &os) {
// 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, bAlloc, CodeViewContainer::Pdb));
}
static void addLinkerModuleSectionSymbol(pdb::DbiModuleDescriptorBuilder &mod,
OutputSection &os) {
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, bAlloc, 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);
}
}
// 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, bAlloc, CodeViewContainer::Pdb));
mod->addSymbol(codeview::SymbolSerializer::writeOneSymbol(
cs, bAlloc, CodeViewContainer::Pdb));
SmallVector<SymbolScope, 4> scopes;
CVSymbol newSym = codeview::SymbolSerializer::writeOneSymbol(
ts, bAlloc, CodeViewContainer::Pdb);
scopeStackOpen(scopes, mod->getNextSymbolOffset(), newSym);
mod->addSymbol(newSym);
newSym = codeview::SymbolSerializer::writeOneSymbol(es, bAlloc,
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 lld::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();
pdb.addNamedStreams();
pdb.addPublicsToPDB();
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);
// Add section contributions. They must be ordered by ascending RVA.
for (OutputSection *os : outputSections) {
addLinkerModuleSectionSymbol(linkerModule, *os);
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)};
dbiBuilder.createSectionMap(sections);
// Add COFF section header stream.
exitOnErr(
dbiBuilder.addDbgStream(pdb::DbgHeaderType::SectionHdr, sectionTable));
}
void PDBLinker::commit(codeview::GUID *guid) {
ExitOnError exitOnErr((config->pdbPath + ": ").str());
// 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 None if a line table was
// not found.
Optional<std::pair<StringRef, uint32_t>>
lld::coff::getFileLineCodeView(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 None;
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 std::make_pair(filename, *lineNumber);
}
nameIndex = entry.NameIndex;
lineNumber = li.getStartLine();
}
}
if (!nameIndex)
return None;
StringRef filename = exitOnErr(getFileName(cvStrTab, checksums, *nameIndex));
return std::make_pair(filename, *lineNumber);
}
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