| //===- SymbolizableObjectFile.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 |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Implementation of SymbolizableObjectFile class. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "SymbolizableObjectFile.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/ADT/Triple.h" |
| #include "llvm/BinaryFormat/COFF.h" |
| #include "llvm/DebugInfo/DWARF/DWARFContext.h" |
| #include "llvm/DebugInfo/Symbolize/SymbolizableModule.h" |
| #include "llvm/Object/COFF.h" |
| #include "llvm/Object/ObjectFile.h" |
| #include "llvm/Object/SymbolSize.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/DataExtractor.h" |
| #include "llvm/Support/Error.h" |
| #include <algorithm> |
| #include <cstdint> |
| #include <memory> |
| #include <string> |
| #include <system_error> |
| #include <utility> |
| #include <vector> |
| |
| using namespace llvm; |
| using namespace object; |
| using namespace symbolize; |
| |
| static DILineInfoSpecifier |
| getDILineInfoSpecifier(FunctionNameKind FNKind) { |
| return DILineInfoSpecifier( |
| DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, FNKind); |
| } |
| |
| ErrorOr<std::unique_ptr<SymbolizableObjectFile>> |
| SymbolizableObjectFile::create(const object::ObjectFile *Obj, |
| std::unique_ptr<DIContext> DICtx, |
| bool UntagAddresses) { |
| assert(DICtx); |
| std::unique_ptr<SymbolizableObjectFile> res( |
| new SymbolizableObjectFile(Obj, std::move(DICtx), UntagAddresses)); |
| std::unique_ptr<DataExtractor> OpdExtractor; |
| uint64_t OpdAddress = 0; |
| // Find the .opd (function descriptor) section if any, for big-endian |
| // PowerPC64 ELF. |
| if (Obj->getArch() == Triple::ppc64) { |
| for (section_iterator Section : Obj->sections()) { |
| Expected<StringRef> NameOrErr = Section->getName(); |
| if (!NameOrErr) |
| return errorToErrorCode(NameOrErr.takeError()); |
| |
| if (*NameOrErr == ".opd") { |
| Expected<StringRef> E = Section->getContents(); |
| if (!E) |
| return errorToErrorCode(E.takeError()); |
| OpdExtractor.reset(new DataExtractor(*E, Obj->isLittleEndian(), |
| Obj->getBytesInAddress())); |
| OpdAddress = Section->getAddress(); |
| break; |
| } |
| } |
| } |
| std::vector<std::pair<SymbolRef, uint64_t>> Symbols = |
| computeSymbolSizes(*Obj); |
| for (auto &P : Symbols) |
| res->addSymbol(P.first, P.second, OpdExtractor.get(), OpdAddress); |
| |
| // If this is a COFF object and we didn't find any symbols, try the export |
| // table. |
| if (Symbols.empty()) { |
| if (auto *CoffObj = dyn_cast<COFFObjectFile>(Obj)) |
| if (auto EC = res->addCoffExportSymbols(CoffObj)) |
| return EC; |
| } |
| |
| std::vector<std::pair<SymbolDesc, StringRef>> &Fs = res->Functions, |
| &Os = res->Objects; |
| auto Uniquify = [](std::vector<std::pair<SymbolDesc, StringRef>> &S) { |
| // Sort by (Addr,Size,Name). If several SymbolDescs share the same Addr, |
| // pick the one with the largest Size. This helps us avoid symbols with no |
| // size information (Size=0). |
| llvm::sort(S); |
| auto I = S.begin(), E = S.end(), J = S.begin(); |
| while (I != E) { |
| auto OI = I; |
| while (++I != E && OI->first.Addr == I->first.Addr) { |
| } |
| *J++ = I[-1]; |
| } |
| S.erase(J, S.end()); |
| }; |
| Uniquify(Fs); |
| Uniquify(Os); |
| |
| return std::move(res); |
| } |
| |
| SymbolizableObjectFile::SymbolizableObjectFile(const ObjectFile *Obj, |
| std::unique_ptr<DIContext> DICtx, |
| bool UntagAddresses) |
| : Module(Obj), DebugInfoContext(std::move(DICtx)), |
| UntagAddresses(UntagAddresses) {} |
| |
| namespace { |
| |
| struct OffsetNamePair { |
| uint32_t Offset; |
| StringRef Name; |
| |
| bool operator<(const OffsetNamePair &R) const { |
| return Offset < R.Offset; |
| } |
| }; |
| |
| } // end anonymous namespace |
| |
| std::error_code SymbolizableObjectFile::addCoffExportSymbols( |
| const COFFObjectFile *CoffObj) { |
| // Get all export names and offsets. |
| std::vector<OffsetNamePair> ExportSyms; |
| for (const ExportDirectoryEntryRef &Ref : CoffObj->export_directories()) { |
| StringRef Name; |
| uint32_t Offset; |
| if (auto EC = Ref.getSymbolName(Name)) |
| return EC; |
| if (auto EC = Ref.getExportRVA(Offset)) |
| return EC; |
| ExportSyms.push_back(OffsetNamePair{Offset, Name}); |
| } |
| if (ExportSyms.empty()) |
| return std::error_code(); |
| |
| // Sort by ascending offset. |
| array_pod_sort(ExportSyms.begin(), ExportSyms.end()); |
| |
| // Approximate the symbol sizes by assuming they run to the next symbol. |
| // FIXME: This assumes all exports are functions. |
| uint64_t ImageBase = CoffObj->getImageBase(); |
| for (auto I = ExportSyms.begin(), E = ExportSyms.end(); I != E; ++I) { |
| OffsetNamePair &Export = *I; |
| // FIXME: The last export has a one byte size now. |
| uint32_t NextOffset = I != E ? I->Offset : Export.Offset + 1; |
| uint64_t SymbolStart = ImageBase + Export.Offset; |
| uint64_t SymbolSize = NextOffset - Export.Offset; |
| SymbolDesc SD = {SymbolStart, SymbolSize}; |
| Functions.emplace_back(SD, Export.Name); |
| } |
| return std::error_code(); |
| } |
| |
| std::error_code SymbolizableObjectFile::addSymbol(const SymbolRef &Symbol, |
| uint64_t SymbolSize, |
| DataExtractor *OpdExtractor, |
| uint64_t OpdAddress) { |
| // Avoid adding symbols from an unknown/undefined section. |
| const ObjectFile *Obj = Symbol.getObject(); |
| Expected<section_iterator> Sec = Symbol.getSection(); |
| if (!Sec || (Obj && Obj->section_end() == *Sec)) |
| return std::error_code(); |
| Expected<SymbolRef::Type> SymbolTypeOrErr = Symbol.getType(); |
| if (!SymbolTypeOrErr) |
| return errorToErrorCode(SymbolTypeOrErr.takeError()); |
| SymbolRef::Type SymbolType = *SymbolTypeOrErr; |
| if (SymbolType != SymbolRef::ST_Function && SymbolType != SymbolRef::ST_Data) |
| return std::error_code(); |
| Expected<uint64_t> SymbolAddressOrErr = Symbol.getAddress(); |
| if (!SymbolAddressOrErr) |
| return errorToErrorCode(SymbolAddressOrErr.takeError()); |
| uint64_t SymbolAddress = *SymbolAddressOrErr; |
| if (UntagAddresses) { |
| // For kernel addresses, bits 56-63 need to be set, so we sign extend bit 55 |
| // into bits 56-63 instead of masking them out. |
| SymbolAddress &= (1ull << 56) - 1; |
| SymbolAddress = (int64_t(SymbolAddress) << 8) >> 8; |
| } |
| if (OpdExtractor) { |
| // For big-endian PowerPC64 ELF, symbols in the .opd section refer to |
| // function descriptors. The first word of the descriptor is a pointer to |
| // the function's code. |
| // For the purposes of symbolization, pretend the symbol's address is that |
| // of the function's code, not the descriptor. |
| uint64_t OpdOffset = SymbolAddress - OpdAddress; |
| if (OpdExtractor->isValidOffsetForAddress(OpdOffset)) |
| SymbolAddress = OpdExtractor->getAddress(&OpdOffset); |
| } |
| Expected<StringRef> SymbolNameOrErr = Symbol.getName(); |
| if (!SymbolNameOrErr) |
| return errorToErrorCode(SymbolNameOrErr.takeError()); |
| StringRef SymbolName = *SymbolNameOrErr; |
| // Mach-O symbol table names have leading underscore, skip it. |
| if (Module->isMachO() && !SymbolName.empty() && SymbolName[0] == '_') |
| SymbolName = SymbolName.drop_front(); |
| // FIXME: If a function has alias, there are two entries in symbol table |
| // with same address size. Make sure we choose the correct one. |
| auto &M = SymbolType == SymbolRef::ST_Function ? Functions : Objects; |
| SymbolDesc SD = { SymbolAddress, SymbolSize }; |
| M.emplace_back(SD, SymbolName); |
| return std::error_code(); |
| } |
| |
| // Return true if this is a 32-bit x86 PE COFF module. |
| bool SymbolizableObjectFile::isWin32Module() const { |
| auto *CoffObject = dyn_cast<COFFObjectFile>(Module); |
| return CoffObject && CoffObject->getMachine() == COFF::IMAGE_FILE_MACHINE_I386; |
| } |
| |
| uint64_t SymbolizableObjectFile::getModulePreferredBase() const { |
| if (auto *CoffObject = dyn_cast<COFFObjectFile>(Module)) |
| return CoffObject->getImageBase(); |
| return 0; |
| } |
| |
| bool SymbolizableObjectFile::getNameFromSymbolTable(SymbolRef::Type Type, |
| uint64_t Address, |
| std::string &Name, |
| uint64_t &Addr, |
| uint64_t &Size) const { |
| const auto &Symbols = Type == SymbolRef::ST_Function ? Functions : Objects; |
| std::pair<SymbolDesc, StringRef> SD{{Address, UINT64_C(-1)}, StringRef()}; |
| auto SymbolIterator = llvm::upper_bound(Symbols, SD); |
| if (SymbolIterator == Symbols.begin()) |
| return false; |
| --SymbolIterator; |
| if (SymbolIterator->first.Size != 0 && |
| SymbolIterator->first.Addr + SymbolIterator->first.Size <= Address) |
| return false; |
| Name = SymbolIterator->second.str(); |
| Addr = SymbolIterator->first.Addr; |
| Size = SymbolIterator->first.Size; |
| return true; |
| } |
| |
| bool SymbolizableObjectFile::shouldOverrideWithSymbolTable( |
| FunctionNameKind FNKind, bool UseSymbolTable) const { |
| // When DWARF is used with -gline-tables-only / -gmlt, the symbol table gives |
| // better answers for linkage names than the DIContext. Otherwise, we are |
| // probably using PEs and PDBs, and we shouldn't do the override. PE files |
| // generally only contain the names of exported symbols. |
| return FNKind == FunctionNameKind::LinkageName && UseSymbolTable && |
| isa<DWARFContext>(DebugInfoContext.get()); |
| } |
| |
| DILineInfo |
| SymbolizableObjectFile::symbolizeCode(object::SectionedAddress ModuleOffset, |
| FunctionNameKind FNKind, |
| bool UseSymbolTable) const { |
| if (ModuleOffset.SectionIndex == object::SectionedAddress::UndefSection) |
| ModuleOffset.SectionIndex = |
| getModuleSectionIndexForAddress(ModuleOffset.Address); |
| DILineInfo LineInfo = DebugInfoContext->getLineInfoForAddress( |
| ModuleOffset, getDILineInfoSpecifier(FNKind)); |
| |
| // Override function name from symbol table if necessary. |
| if (shouldOverrideWithSymbolTable(FNKind, UseSymbolTable)) { |
| std::string FunctionName; |
| uint64_t Start, Size; |
| if (getNameFromSymbolTable(SymbolRef::ST_Function, ModuleOffset.Address, |
| FunctionName, Start, Size)) { |
| LineInfo.FunctionName = FunctionName; |
| } |
| } |
| return LineInfo; |
| } |
| |
| DIInliningInfo SymbolizableObjectFile::symbolizeInlinedCode( |
| object::SectionedAddress ModuleOffset, FunctionNameKind FNKind, |
| bool UseSymbolTable) const { |
| if (ModuleOffset.SectionIndex == object::SectionedAddress::UndefSection) |
| ModuleOffset.SectionIndex = |
| getModuleSectionIndexForAddress(ModuleOffset.Address); |
| DIInliningInfo InlinedContext = DebugInfoContext->getInliningInfoForAddress( |
| ModuleOffset, getDILineInfoSpecifier(FNKind)); |
| |
| // Make sure there is at least one frame in context. |
| if (InlinedContext.getNumberOfFrames() == 0) |
| InlinedContext.addFrame(DILineInfo()); |
| |
| // Override the function name in lower frame with name from symbol table. |
| if (shouldOverrideWithSymbolTable(FNKind, UseSymbolTable)) { |
| std::string FunctionName; |
| uint64_t Start, Size; |
| if (getNameFromSymbolTable(SymbolRef::ST_Function, ModuleOffset.Address, |
| FunctionName, Start, Size)) { |
| InlinedContext.getMutableFrame(InlinedContext.getNumberOfFrames() - 1) |
| ->FunctionName = FunctionName; |
| } |
| } |
| |
| return InlinedContext; |
| } |
| |
| DIGlobal SymbolizableObjectFile::symbolizeData( |
| object::SectionedAddress ModuleOffset) const { |
| DIGlobal Res; |
| getNameFromSymbolTable(SymbolRef::ST_Data, ModuleOffset.Address, Res.Name, |
| Res.Start, Res.Size); |
| return Res; |
| } |
| |
| std::vector<DILocal> SymbolizableObjectFile::symbolizeFrame( |
| object::SectionedAddress ModuleOffset) const { |
| if (ModuleOffset.SectionIndex == object::SectionedAddress::UndefSection) |
| ModuleOffset.SectionIndex = |
| getModuleSectionIndexForAddress(ModuleOffset.Address); |
| return DebugInfoContext->getLocalsForAddress(ModuleOffset); |
| } |
| |
| /// Search for the first occurence of specified Address in ObjectFile. |
| uint64_t SymbolizableObjectFile::getModuleSectionIndexForAddress( |
| uint64_t Address) const { |
| |
| for (SectionRef Sec : Module->sections()) { |
| if (!Sec.isText() || Sec.isVirtual()) |
| continue; |
| |
| if (Address >= Sec.getAddress() && |
| Address < Sec.getAddress() + Sec.getSize()) |
| return Sec.getIndex(); |
| } |
| |
| return object::SectionedAddress::UndefSection; |
| } |
