//===-- DWARFContext.cpp --------------------------------------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// #include "llvm/DebugInfo/DWARF/DWARFContext.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/StringSwitch.h" #include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h" #include "llvm/DebugInfo/DWARF/DWARFDebugArangeSet.h" #include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h" #include "llvm/Support/Compression.h" #include "llvm/Support/Dwarf.h" #include "llvm/Support/Format.h" #include "llvm/Support/Path.h" #include "llvm/Support/raw_ostream.h" #include <algorithm> using namespace llvm; using namespace dwarf; using namespace object; #define DEBUG_TYPE "dwarf" typedef DWARFDebugLine::LineTable DWARFLineTable; typedef DILineInfoSpecifier::FileLineInfoKind FileLineInfoKind; typedef DILineInfoSpecifier::FunctionNameKind FunctionNameKind; static void dumpPubSection(raw_ostream &OS, StringRef Name, StringRef Data, bool LittleEndian, bool GnuStyle) { OS << "\n." << Name << " contents:\n"; DataExtractor pubNames(Data, LittleEndian, 0); uint32_t offset = 0; while (pubNames.isValidOffset(offset)) { OS << "length = " << format("0x%08x", pubNames.getU32(&offset)); OS << " version = " << format("0x%04x", pubNames.getU16(&offset)); OS << " unit_offset = " << format("0x%08x", pubNames.getU32(&offset)); OS << " unit_size = " << format("0x%08x", pubNames.getU32(&offset)) << '\n'; if (GnuStyle) OS << "Offset Linkage Kind Name\n"; else OS << "Offset Name\n"; while (offset < Data.size()) { uint32_t dieRef = pubNames.getU32(&offset); if (dieRef == 0) break; OS << format("0x%8.8x ", dieRef); if (GnuStyle) { PubIndexEntryDescriptor desc(pubNames.getU8(&offset)); OS << format("%-8s", dwarf::GDBIndexEntryLinkageString(desc.Linkage)) << ' ' << format("%-8s", dwarf::GDBIndexEntryKindString(desc.Kind)) << ' '; } OS << '\"' << pubNames.getCStr(&offset) << "\"\n"; } } } static void dumpAccelSection(raw_ostream &OS, StringRef Name, const DWARFSection& Section, StringRef StringSection, bool LittleEndian) { DataExtractor AccelSection(Section.Data, LittleEndian, 0); DataExtractor StrData(StringSection, LittleEndian, 0); OS << "\n." << Name << " contents:\n"; DWARFAcceleratorTable Accel(AccelSection, StrData, Section.Relocs); if (!Accel.extract()) return; Accel.dump(OS); } void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType) { if (DumpType == DIDT_All || DumpType == DIDT_Abbrev) { OS << ".debug_abbrev contents:\n"; getDebugAbbrev()->dump(OS); } if (DumpType == DIDT_All || DumpType == DIDT_AbbrevDwo) if (const DWARFDebugAbbrev *D = getDebugAbbrevDWO()) { OS << "\n.debug_abbrev.dwo contents:\n"; D->dump(OS); } if (DumpType == DIDT_All || DumpType == DIDT_Info) { OS << "\n.debug_info contents:\n"; for (const auto &CU : compile_units()) CU->dump(OS); } if ((DumpType == DIDT_All || DumpType == DIDT_InfoDwo) && getNumDWOCompileUnits()) { OS << "\n.debug_info.dwo contents:\n"; for (const auto &DWOCU : dwo_compile_units()) DWOCU->dump(OS); } if ((DumpType == DIDT_All || DumpType == DIDT_Types) && getNumTypeUnits()) { OS << "\n.debug_types contents:\n"; for (const auto &TUS : type_unit_sections()) for (const auto &TU : TUS) TU->dump(OS); } if ((DumpType == DIDT_All || DumpType == DIDT_TypesDwo) && getNumDWOTypeUnits()) { OS << "\n.debug_types.dwo contents:\n"; for (const auto &DWOTUS : dwo_type_unit_sections()) for (const auto &DWOTU : DWOTUS) DWOTU->dump(OS); } if (DumpType == DIDT_All || DumpType == DIDT_Loc) { OS << "\n.debug_loc contents:\n"; getDebugLoc()->dump(OS); } if (DumpType == DIDT_All || DumpType == DIDT_LocDwo) { OS << "\n.debug_loc.dwo contents:\n"; getDebugLocDWO()->dump(OS); } if (DumpType == DIDT_All || DumpType == DIDT_Frames) { OS << "\n.debug_frame contents:\n"; getDebugFrame()->dump(OS); } if (DumpType == DIDT_All || DumpType == DIDT_Macro) { OS << "\n.debug_macinfo contents:\n"; getDebugMacro()->dump(OS); } uint32_t offset = 0; if (DumpType == DIDT_All || DumpType == DIDT_Aranges) { OS << "\n.debug_aranges contents:\n"; DataExtractor arangesData(getARangeSection(), isLittleEndian(), 0); DWARFDebugArangeSet set; while (set.extract(arangesData, &offset)) set.dump(OS); } uint8_t savedAddressByteSize = 0; if (DumpType == DIDT_All || DumpType == DIDT_Line) { OS << "\n.debug_line contents:\n"; for (const auto &CU : compile_units()) { savedAddressByteSize = CU->getAddressByteSize(); const auto *CUDIE = CU->getUnitDIE(); if (CUDIE == nullptr) continue; unsigned stmtOffset = CUDIE->getAttributeValueAsSectionOffset( CU.get(), DW_AT_stmt_list, -1U); if (stmtOffset != -1U) { DataExtractor lineData(getLineSection().Data, isLittleEndian(), savedAddressByteSize); DWARFDebugLine::LineTable LineTable; LineTable.parse(lineData, &getLineSection().Relocs, &stmtOffset); LineTable.dump(OS); } } } if (DumpType == DIDT_All || DumpType == DIDT_CUIndex) { OS << "\n.debug_cu_index contents:\n"; getCUIndex().dump(OS); } if (DumpType == DIDT_All || DumpType == DIDT_TUIndex) { OS << "\n.debug_tu_index contents:\n"; getTUIndex().dump(OS); } if (DumpType == DIDT_All || DumpType == DIDT_LineDwo) { OS << "\n.debug_line.dwo contents:\n"; unsigned stmtOffset = 0; DataExtractor lineData(getLineDWOSection().Data, isLittleEndian(), savedAddressByteSize); DWARFDebugLine::LineTable LineTable; while (LineTable.Prologue.parse(lineData, &stmtOffset)) { LineTable.dump(OS); LineTable.clear(); } } if (DumpType == DIDT_All || DumpType == DIDT_Str) { OS << "\n.debug_str contents:\n"; DataExtractor strData(getStringSection(), isLittleEndian(), 0); offset = 0; uint32_t strOffset = 0; while (const char *s = strData.getCStr(&offset)) { OS << format("0x%8.8x: \"%s\"\n", strOffset, s); strOffset = offset; } } if ((DumpType == DIDT_All || DumpType == DIDT_StrDwo) && !getStringDWOSection().empty()) { OS << "\n.debug_str.dwo contents:\n"; DataExtractor strDWOData(getStringDWOSection(), isLittleEndian(), 0); offset = 0; uint32_t strDWOOffset = 0; while (const char *s = strDWOData.getCStr(&offset)) { OS << format("0x%8.8x: \"%s\"\n", strDWOOffset, s); strDWOOffset = offset; } } if (DumpType == DIDT_All || DumpType == DIDT_Ranges) { OS << "\n.debug_ranges contents:\n"; // In fact, different compile units may have different address byte // sizes, but for simplicity we just use the address byte size of the last // compile unit (there is no easy and fast way to associate address range // list and the compile unit it describes). DataExtractor rangesData(getRangeSection(), isLittleEndian(), savedAddressByteSize); offset = 0; DWARFDebugRangeList rangeList; while (rangeList.extract(rangesData, &offset)) rangeList.dump(OS); } if (DumpType == DIDT_All || DumpType == DIDT_Pubnames) dumpPubSection(OS, "debug_pubnames", getPubNamesSection(), isLittleEndian(), false); if (DumpType == DIDT_All || DumpType == DIDT_Pubtypes) dumpPubSection(OS, "debug_pubtypes", getPubTypesSection(), isLittleEndian(), false); if (DumpType == DIDT_All || DumpType == DIDT_GnuPubnames) dumpPubSection(OS, "debug_gnu_pubnames", getGnuPubNamesSection(), isLittleEndian(), true /* GnuStyle */); if (DumpType == DIDT_All || DumpType == DIDT_GnuPubtypes) dumpPubSection(OS, "debug_gnu_pubtypes", getGnuPubTypesSection(), isLittleEndian(), true /* GnuStyle */); if ((DumpType == DIDT_All || DumpType == DIDT_StrOffsetsDwo) && !getStringOffsetDWOSection().empty()) { OS << "\n.debug_str_offsets.dwo contents:\n"; DataExtractor strOffsetExt(getStringOffsetDWOSection(), isLittleEndian(), 0); offset = 0; uint64_t size = getStringOffsetDWOSection().size(); while (offset < size) { OS << format("0x%8.8x: ", offset); OS << format("%8.8x\n", strOffsetExt.getU32(&offset)); } } if (DumpType == DIDT_All || DumpType == DIDT_AppleNames) dumpAccelSection(OS, "apple_names", getAppleNamesSection(), getStringSection(), isLittleEndian()); if (DumpType == DIDT_All || DumpType == DIDT_AppleTypes) dumpAccelSection(OS, "apple_types", getAppleTypesSection(), getStringSection(), isLittleEndian()); if (DumpType == DIDT_All || DumpType == DIDT_AppleNamespaces) dumpAccelSection(OS, "apple_namespaces", getAppleNamespacesSection(), getStringSection(), isLittleEndian()); if (DumpType == DIDT_All || DumpType == DIDT_AppleObjC) dumpAccelSection(OS, "apple_objc", getAppleObjCSection(), getStringSection(), isLittleEndian()); } const DWARFUnitIndex &DWARFContext::getCUIndex() { if (CUIndex) return *CUIndex; DataExtractor CUIndexData(getCUIndexSection(), isLittleEndian(), 0); CUIndex = llvm::make_unique<DWARFUnitIndex>(DW_SECT_INFO); CUIndex->parse(CUIndexData); return *CUIndex; } const DWARFUnitIndex &DWARFContext::getTUIndex() { if (TUIndex) return *TUIndex; DataExtractor TUIndexData(getTUIndexSection(), isLittleEndian(), 0); TUIndex = llvm::make_unique<DWARFUnitIndex>(DW_SECT_TYPES); TUIndex->parse(TUIndexData); return *TUIndex; } const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() { if (Abbrev) return Abbrev.get(); DataExtractor abbrData(getAbbrevSection(), isLittleEndian(), 0); Abbrev.reset(new DWARFDebugAbbrev()); Abbrev->extract(abbrData); return Abbrev.get(); } const DWARFDebugAbbrev *DWARFContext::getDebugAbbrevDWO() { if (AbbrevDWO) return AbbrevDWO.get(); DataExtractor abbrData(getAbbrevDWOSection(), isLittleEndian(), 0); AbbrevDWO.reset(new DWARFDebugAbbrev()); AbbrevDWO->extract(abbrData); return AbbrevDWO.get(); } const DWARFDebugLoc *DWARFContext::getDebugLoc() { if (Loc) return Loc.get(); DataExtractor LocData(getLocSection().Data, isLittleEndian(), 0); Loc.reset(new DWARFDebugLoc(getLocSection().Relocs)); // assume all compile units have the same address byte size if (getNumCompileUnits()) Loc->parse(LocData, getCompileUnitAtIndex(0)->getAddressByteSize()); return Loc.get(); } const DWARFDebugLocDWO *DWARFContext::getDebugLocDWO() { if (LocDWO) return LocDWO.get(); DataExtractor LocData(getLocDWOSection().Data, isLittleEndian(), 0); LocDWO.reset(new DWARFDebugLocDWO()); LocDWO->parse(LocData); return LocDWO.get(); } const DWARFDebugAranges *DWARFContext::getDebugAranges() { if (Aranges) return Aranges.get(); Aranges.reset(new DWARFDebugAranges()); Aranges->generate(this); return Aranges.get(); } const DWARFDebugFrame *DWARFContext::getDebugFrame() { if (DebugFrame) return DebugFrame.get(); // There's a "bug" in the DWARFv3 standard with respect to the target address // size within debug frame sections. While DWARF is supposed to be independent // of its container, FDEs have fields with size being "target address size", // which isn't specified in DWARF in general. It's only specified for CUs, but // .eh_frame can appear without a .debug_info section. Follow the example of // other tools (libdwarf) and extract this from the container (ObjectFile // provides this information). This problem is fixed in DWARFv4 // See this dwarf-discuss discussion for more details: // http://lists.dwarfstd.org/htdig.cgi/dwarf-discuss-dwarfstd.org/2011-December/001173.html DataExtractor debugFrameData(getDebugFrameSection(), isLittleEndian(), getAddressSize()); DebugFrame.reset(new DWARFDebugFrame()); DebugFrame->parse(debugFrameData); return DebugFrame.get(); } const DWARFDebugMacro *DWARFContext::getDebugMacro() { if (Macro) return Macro.get(); DataExtractor MacinfoData(getMacinfoSection(), isLittleEndian(), 0); Macro.reset(new DWARFDebugMacro()); Macro->parse(MacinfoData); return Macro.get(); } const DWARFLineTable * DWARFContext::getLineTableForUnit(DWARFUnit *U) { if (!Line) Line.reset(new DWARFDebugLine(&getLineSection().Relocs)); const auto *UnitDIE = U->getUnitDIE(); if (UnitDIE == nullptr) return nullptr; unsigned stmtOffset = UnitDIE->getAttributeValueAsSectionOffset(U, DW_AT_stmt_list, -1U); if (stmtOffset == -1U) return nullptr; // No line table for this compile unit. stmtOffset += U->getLineTableOffset(); // See if the line table is cached. if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset)) return lt; // We have to parse it first. DataExtractor lineData(U->getLineSection(), isLittleEndian(), U->getAddressByteSize()); return Line->getOrParseLineTable(lineData, stmtOffset); } void DWARFContext::parseCompileUnits() { CUs.parse(*this, getInfoSection()); } void DWARFContext::parseTypeUnits() { if (!TUs.empty()) return; for (const auto &I : getTypesSections()) { TUs.emplace_back(); TUs.back().parse(*this, I.second); } } void DWARFContext::parseDWOCompileUnits() { DWOCUs.parseDWO(*this, getInfoDWOSection()); } void DWARFContext::parseDWOTypeUnits() { if (!DWOTUs.empty()) return; for (const auto &I : getTypesDWOSections()) { DWOTUs.emplace_back(); DWOTUs.back().parseDWO(*this, I.second); } } DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t Offset) { parseCompileUnits(); return CUs.getUnitForOffset(Offset); } DWARFCompileUnit *DWARFContext::getCompileUnitForAddress(uint64_t Address) { // First, get the offset of the compile unit. uint32_t CUOffset = getDebugAranges()->findAddress(Address); // Retrieve the compile unit. return getCompileUnitForOffset(CUOffset); } static bool getFunctionNameForAddress(DWARFCompileUnit *CU, uint64_t Address, FunctionNameKind Kind, std::string &FunctionName) { if (Kind == FunctionNameKind::None) return false; // The address may correspond to instruction in some inlined function, // so we have to build the chain of inlined functions and take the // name of the topmost function in it. const DWARFDebugInfoEntryInlinedChain &InlinedChain = CU->getInlinedChainForAddress(Address); if (InlinedChain.DIEs.size() == 0) return false; const DWARFDebugInfoEntryMinimal &TopFunctionDIE = InlinedChain.DIEs[0]; if (const char *Name = TopFunctionDIE.getSubroutineName(InlinedChain.U, Kind)) { FunctionName = Name; return true; } return false; } DILineInfo DWARFContext::getLineInfoForAddress(uint64_t Address, DILineInfoSpecifier Spec) { DILineInfo Result; DWARFCompileUnit *CU = getCompileUnitForAddress(Address); if (!CU) return Result; getFunctionNameForAddress(CU, Address, Spec.FNKind, Result.FunctionName); if (Spec.FLIKind != FileLineInfoKind::None) { if (const DWARFLineTable *LineTable = getLineTableForUnit(CU)) LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(), Spec.FLIKind, Result); } return Result; } DILineInfoTable DWARFContext::getLineInfoForAddressRange(uint64_t Address, uint64_t Size, DILineInfoSpecifier Spec) { DILineInfoTable Lines; DWARFCompileUnit *CU = getCompileUnitForAddress(Address); if (!CU) return Lines; std::string FunctionName = "<invalid>"; getFunctionNameForAddress(CU, Address, Spec.FNKind, FunctionName); // If the Specifier says we don't need FileLineInfo, just // return the top-most function at the starting address. if (Spec.FLIKind == FileLineInfoKind::None) { DILineInfo Result; Result.FunctionName = FunctionName; Lines.push_back(std::make_pair(Address, Result)); return Lines; } const DWARFLineTable *LineTable = getLineTableForUnit(CU); // Get the index of row we're looking for in the line table. std::vector<uint32_t> RowVector; if (!LineTable->lookupAddressRange(Address, Size, RowVector)) return Lines; for (uint32_t RowIndex : RowVector) { // Take file number and line/column from the row. const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex]; DILineInfo Result; LineTable->getFileNameByIndex(Row.File, CU->getCompilationDir(), Spec.FLIKind, Result.FileName); Result.FunctionName = FunctionName; Result.Line = Row.Line; Result.Column = Row.Column; Lines.push_back(std::make_pair(Row.Address, Result)); } return Lines; } DIInliningInfo DWARFContext::getInliningInfoForAddress(uint64_t Address, DILineInfoSpecifier Spec) { DIInliningInfo InliningInfo; DWARFCompileUnit *CU = getCompileUnitForAddress(Address); if (!CU) return InliningInfo; const DWARFLineTable *LineTable = nullptr; const DWARFDebugInfoEntryInlinedChain &InlinedChain = CU->getInlinedChainForAddress(Address); if (InlinedChain.DIEs.size() == 0) { // If there is no DIE for address (e.g. it is in unavailable .dwo file), // try to at least get file/line info from symbol table. if (Spec.FLIKind != FileLineInfoKind::None) { DILineInfo Frame; LineTable = getLineTableForUnit(CU); if (LineTable && LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(), Spec.FLIKind, Frame)) InliningInfo.addFrame(Frame); } return InliningInfo; } uint32_t CallFile = 0, CallLine = 0, CallColumn = 0; for (uint32_t i = 0, n = InlinedChain.DIEs.size(); i != n; i++) { const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain.DIEs[i]; DILineInfo Frame; // Get function name if necessary. if (const char *Name = FunctionDIE.getSubroutineName(InlinedChain.U, Spec.FNKind)) Frame.FunctionName = Name; if (Spec.FLIKind != FileLineInfoKind::None) { if (i == 0) { // For the topmost frame, initialize the line table of this // compile unit and fetch file/line info from it. LineTable = getLineTableForUnit(CU); // For the topmost routine, get file/line info from line table. if (LineTable) LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(), Spec.FLIKind, Frame); } else { // Otherwise, use call file, call line and call column from // previous DIE in inlined chain. if (LineTable) LineTable->getFileNameByIndex(CallFile, CU->getCompilationDir(), Spec.FLIKind, Frame.FileName); Frame.Line = CallLine; Frame.Column = CallColumn; } // Get call file/line/column of a current DIE. if (i + 1 < n) { FunctionDIE.getCallerFrame(InlinedChain.U, CallFile, CallLine, CallColumn); } } InliningInfo.addFrame(Frame); } return InliningInfo; } static bool consumeCompressedDebugSectionHeader(StringRef &data, uint64_t &OriginalSize) { // Consume "ZLIB" prefix. if (!data.startswith("ZLIB")) return false; data = data.substr(4); // Consume uncompressed section size (big-endian 8 bytes). DataExtractor extractor(data, false, 8); uint32_t Offset = 0; OriginalSize = extractor.getU64(&Offset); if (Offset == 0) return false; data = data.substr(Offset); return true; } DWARFContextInMemory::DWARFContextInMemory(const object::ObjectFile &Obj, const LoadedObjectInfo *L) : IsLittleEndian(Obj.isLittleEndian()), AddressSize(Obj.getBytesInAddress()) { for (const SectionRef &Section : Obj.sections()) { StringRef name; Section.getName(name); // Skip BSS and Virtual sections, they aren't interesting. bool IsBSS = Section.isBSS(); if (IsBSS) continue; bool IsVirtual = Section.isVirtual(); if (IsVirtual) continue; StringRef data; section_iterator RelocatedSection = Section.getRelocatedSection(); // Try to obtain an already relocated version of this section. // Else use the unrelocated section from the object file. We'll have to // apply relocations ourselves later. if (!L || !L->getLoadedSectionContents(*RelocatedSection,data)) Section.getContents(data); name = name.substr(name.find_first_not_of("._")); // Skip . and _ prefixes. // Check if debug info section is compressed with zlib. if (name.startswith("zdebug_")) { uint64_t OriginalSize; if (!zlib::isAvailable() || !consumeCompressedDebugSectionHeader(data, OriginalSize)) continue; UncompressedSections.resize(UncompressedSections.size() + 1); if (zlib::uncompress(data, UncompressedSections.back(), OriginalSize) != zlib::StatusOK) { UncompressedSections.pop_back(); continue; } // Make data point to uncompressed section contents and save its contents. name = name.substr(1); data = UncompressedSections.back(); } StringRef *SectionData = StringSwitch<StringRef *>(name) .Case("debug_info", &InfoSection.Data) .Case("debug_abbrev", &AbbrevSection) .Case("debug_loc", &LocSection.Data) .Case("debug_line", &LineSection.Data) .Case("debug_aranges", &ARangeSection) .Case("debug_frame", &DebugFrameSection) .Case("debug_str", &StringSection) .Case("debug_ranges", &RangeSection) .Case("debug_macinfo", &MacinfoSection) .Case("debug_pubnames", &PubNamesSection) .Case("debug_pubtypes", &PubTypesSection) .Case("debug_gnu_pubnames", &GnuPubNamesSection) .Case("debug_gnu_pubtypes", &GnuPubTypesSection) .Case("debug_info.dwo", &InfoDWOSection.Data) .Case("debug_abbrev.dwo", &AbbrevDWOSection) .Case("debug_loc.dwo", &LocDWOSection.Data) .Case("debug_line.dwo", &LineDWOSection.Data) .Case("debug_str.dwo", &StringDWOSection) .Case("debug_str_offsets.dwo", &StringOffsetDWOSection) .Case("debug_addr", &AddrSection) .Case("apple_names", &AppleNamesSection.Data) .Case("apple_types", &AppleTypesSection.Data) .Case("apple_namespaces", &AppleNamespacesSection.Data) .Case("apple_namespac", &AppleNamespacesSection.Data) .Case("apple_objc", &AppleObjCSection.Data) .Case("debug_cu_index", &CUIndexSection) .Case("debug_tu_index", &TUIndexSection) // Any more debug info sections go here. .Default(nullptr); if (SectionData) { *SectionData = data; if (name == "debug_ranges") { // FIXME: Use the other dwo range section when we emit it. RangeDWOSection = data; } } else if (name == "debug_types") { // Find debug_types data by section rather than name as there are // multiple, comdat grouped, debug_types sections. TypesSections[Section].Data = data; } else if (name == "debug_types.dwo") { TypesDWOSections[Section].Data = data; } if (RelocatedSection == Obj.section_end()) continue; StringRef RelSecName; StringRef RelSecData; RelocatedSection->getName(RelSecName); // If the section we're relocating was relocated already by the JIT, // then we used the relocated version above, so we do not need to process // relocations for it now. if (L && L->getLoadedSectionContents(*RelocatedSection,RelSecData)) continue; // In Mach-o files, the relocations do not need to be applied if // there is no load offset to apply. The value read at the // relocation point already factors in the section address // (actually applying the relocations will produce wrong results // as the section address will be added twice). if (!L && isa<MachOObjectFile>(&Obj)) continue; RelSecName = RelSecName.substr( RelSecName.find_first_not_of("._")); // Skip . and _ prefixes. // TODO: Add support for relocations in other sections as needed. // Record relocations for the debug_info and debug_line sections. RelocAddrMap *Map = StringSwitch<RelocAddrMap*>(RelSecName) .Case("debug_info", &InfoSection.Relocs) .Case("debug_loc", &LocSection.Relocs) .Case("debug_info.dwo", &InfoDWOSection.Relocs) .Case("debug_line", &LineSection.Relocs) .Case("apple_names", &AppleNamesSection.Relocs) .Case("apple_types", &AppleTypesSection.Relocs) .Case("apple_namespaces", &AppleNamespacesSection.Relocs) .Case("apple_namespac", &AppleNamespacesSection.Relocs) .Case("apple_objc", &AppleObjCSection.Relocs) .Default(nullptr); if (!Map) { // Find debug_types relocs by section rather than name as there are // multiple, comdat grouped, debug_types sections. if (RelSecName == "debug_types") Map = &TypesSections[*RelocatedSection].Relocs; else if (RelSecName == "debug_types.dwo") Map = &TypesDWOSections[*RelocatedSection].Relocs; else continue; } if (Section.relocation_begin() != Section.relocation_end()) { uint64_t SectionSize = RelocatedSection->getSize(); for (const RelocationRef &Reloc : Section.relocations()) { uint64_t Address = Reloc.getOffset(); uint64_t Type = Reloc.getType(); uint64_t SymAddr = 0; uint64_t SectionLoadAddress = 0; object::symbol_iterator Sym = Reloc.getSymbol(); object::section_iterator RSec = Obj.section_end(); // First calculate the address of the symbol or section as it appears // in the objct file if (Sym != Obj.symbol_end()) { ErrorOr<uint64_t> SymAddrOrErr = Sym->getAddress(); if (std::error_code EC = SymAddrOrErr.getError()) { errs() << "error: failed to compute symbol address: " << EC.message() << '\n'; continue; } SymAddr = *SymAddrOrErr; // Also remember what section this symbol is in for later RSec = *Sym->getSection(); } else if (auto *MObj = dyn_cast<MachOObjectFile>(&Obj)) { // MachO also has relocations that point to sections and // scattered relocations. auto RelocInfo = MObj->getRelocation(Reloc.getRawDataRefImpl()); if (MObj->isRelocationScattered(RelocInfo)) { // FIXME: it's not clear how to correctly handle scattered // relocations. continue; } else { RSec = MObj->getRelocationSection(Reloc.getRawDataRefImpl()); SymAddr = RSec->getAddress(); } } // If we are given load addresses for the sections, we need to adjust: // SymAddr = (Address of Symbol Or Section in File) - // (Address of Section in File) + // (Load Address of Section) if (L != nullptr && RSec != Obj.section_end()) { // RSec is now either the section being targeted or the section // containing the symbol being targeted. In either case, // we need to perform the same computation. StringRef SecName; RSec->getName(SecName); // llvm::dbgs() << "Name: '" << SecName // << "', RSec: " << RSec->getRawDataRefImpl() // << ", Section: " << Section.getRawDataRefImpl() << "\n"; SectionLoadAddress = L->getSectionLoadAddress(*RSec); if (SectionLoadAddress != 0) SymAddr += SectionLoadAddress - RSec->getAddress(); } object::RelocVisitor V(Obj); object::RelocToApply R(V.visit(Type, Reloc, SymAddr)); if (V.error()) { SmallString<32> Name; Reloc.getTypeName(Name); errs() << "error: failed to compute relocation: " << Name << "\n"; continue; } if (Address + R.Width > SectionSize) { errs() << "error: " << R.Width << "-byte relocation starting " << Address << " bytes into section " << name << " which is " << SectionSize << " bytes long.\n"; continue; } if (R.Width > 8) { errs() << "error: can't handle a relocation of more than 8 bytes at " "a time.\n"; continue; } DEBUG(dbgs() << "Writing " << format("%p", R.Value) << " at " << format("%p", Address) << " with width " << format("%d", R.Width) << "\n"); Map->insert(std::make_pair(Address, std::make_pair(R.Width, R.Value))); } } } } void DWARFContextInMemory::anchor() { }