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Diffstat (limited to 'lib/ReaderWriter/ELF/DefaultLayout.h')
| -rw-r--r-- | lib/ReaderWriter/ELF/DefaultLayout.h | 1050 |
1 files changed, 0 insertions, 1050 deletions
diff --git a/lib/ReaderWriter/ELF/DefaultLayout.h b/lib/ReaderWriter/ELF/DefaultLayout.h deleted file mode 100644 index 9af3b8eb8dc6..000000000000 --- a/lib/ReaderWriter/ELF/DefaultLayout.h +++ /dev/null @@ -1,1050 +0,0 @@ -//===- lib/ReaderWriter/ELF/DefaultLayout.h -------------------------------===// -// -// The LLVM Linker -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// - -#ifndef LLD_READER_WRITER_ELF_DEFAULT_LAYOUT_H -#define LLD_READER_WRITER_ELF_DEFAULT_LAYOUT_H - -#include "Atoms.h" -#include "Chunk.h" -#include "HeaderChunks.h" -#include "Layout.h" -#include "SectionChunks.h" -#include "SegmentChunks.h" -#include "lld/Core/Instrumentation.h" -#include "lld/Core/STDExtras.h" -#include "llvm/ADT/ArrayRef.h" -#include "llvm/ADT/DenseMap.h" -#include "llvm/ADT/DenseSet.h" -#include "llvm/ADT/Hashing.h" -#include "llvm/ADT/SmallVector.h" -#include "llvm/ADT/StringExtras.h" -#include "llvm/ADT/StringMap.h" -#include "llvm/ADT/StringRef.h" -#include "llvm/ADT/StringSwitch.h" -#include "llvm/Support/Errc.h" -#include "llvm/Support/Format.h" -#include <map> -#include <unordered_map> - -namespace lld { -namespace elf { -/// \brief The DefaultLayout class is used by the Writer to arrange -/// sections and segments in the order determined by the target ELF -/// format. The writer creates a single instance of the DefaultLayout -/// class -template<class ELFT> -class DefaultLayout : public Layout { -public: - - // The order in which the sections appear in the output file - // If its determined, that the layout needs to change - // just changing the order of enumerations would essentially - // change the layout in the output file - // Change the enumerations so that Target can override and stick - // a section anywhere it wants to - enum DefaultSectionOrder { - ORDER_NOT_DEFINED = 0, - ORDER_INTERP = 10, - ORDER_RO_NOTE = 15, - ORDER_HASH = 30, - ORDER_DYNAMIC_SYMBOLS = 40, - ORDER_DYNAMIC_STRINGS = 50, - ORDER_DYNAMIC_RELOCS = 52, - ORDER_DYNAMIC_PLT_RELOCS = 54, - ORDER_INIT = 60, - ORDER_PLT = 70, - ORDER_TEXT = 80, - ORDER_FINI = 90, - ORDER_REL = 95, - ORDER_RODATA = 100, - ORDER_EH_FRAME = 110, - ORDER_EH_FRAMEHDR = 120, - ORDER_TDATA = 124, - ORDER_TBSS = 128, - ORDER_CTORS = 130, - ORDER_DTORS = 140, - ORDER_INIT_ARRAY = 150, - ORDER_FINI_ARRAY = 160, - ORDER_DYNAMIC = 170, - ORDER_GOT = 180, - ORDER_GOT_PLT = 190, - ORDER_DATA = 200, - ORDER_RW_NOTE = 205, - ORDER_BSS = 210, - ORDER_NOALLOC = 215, - ORDER_OTHER = 220, - ORDER_SECTION_STRINGS = 230, - ORDER_SYMBOL_TABLE = 240, - ORDER_STRING_TABLE = 250, - ORDER_SECTION_HEADERS = 260 - }; - -public: - - // The Key used for creating Sections - // The sections are created using - // SectionName, contentPermissions - struct SectionKey { - SectionKey(StringRef name, DefinedAtom::ContentPermissions perm, - StringRef path) - : _name(name), _perm(perm), _path(path) {} - - // Data members - StringRef _name; - DefinedAtom::ContentPermissions _perm; - StringRef _path; - }; - - struct SectionKeyHash { - int64_t operator()(const SectionKey &k) const { - return llvm::hash_combine(k._name, k._perm, k._path); - } - }; - - struct SectionKeyEq { - bool operator()(const SectionKey &lhs, const SectionKey &rhs) const { - return ((lhs._name == rhs._name) && (lhs._perm == rhs._perm) && - (lhs._path == rhs._path)); - } - }; - - typedef typename std::vector<Chunk<ELFT> *>::iterator ChunkIter; - typedef typename std::vector<Segment<ELFT> *>::iterator SegmentIter; - - // The additional segments are used to figure out - // if there is a segment by that type already created - // For example : PT_TLS, we have two sections .tdata/.tbss - // that are part of PT_TLS, we need to create this additional - // segment only once - typedef std::pair<int64_t, int64_t> AdditionalSegmentKey; - // The segments are created using - // SegmentName, Segment flags - typedef std::pair<StringRef, int64_t> SegmentKey; - - // HashKey for the Segment - class SegmentHashKey { - public: - int64_t operator() (const SegmentKey &k) const { - // k.first = SegmentName - // k.second = SegmentFlags - return llvm::hash_combine(k.first, k.second); - } - }; - - class AdditionalSegmentHashKey { - public: - int64_t operator()(const AdditionalSegmentKey &k) const { - // k.first = SegmentName - // k.second = SegmentFlags - return llvm::hash_combine(k.first, k.second); - } - }; - - // Output Sections contain the map of Sectionnames to a vector of sections, - // that have been merged to form a single section - typedef llvm::StringMap<OutputSection<ELFT> *> OutputSectionMapT; - typedef - typename std::vector<OutputSection<ELFT> *>::iterator OutputSectionIter; - - typedef std::unordered_map<SectionKey, AtomSection<ELFT> *, SectionKeyHash, - SectionKeyEq> SectionMapT; - typedef std::unordered_map<AdditionalSegmentKey, Segment<ELFT> *, - AdditionalSegmentHashKey> AdditionalSegmentMapT; - typedef std::unordered_map<SegmentKey, Segment<ELFT> *, SegmentHashKey> - SegmentMapT; - - /// \brief find a absolute atom pair given a absolute atom name - struct FindByName { - const std::string _name; - FindByName(StringRef name) : _name(name) {} - bool operator()(const lld::AtomLayout *j) { return j->_atom->name() == _name; } - }; - - typedef typename std::vector<lld::AtomLayout *>::iterator AbsoluteAtomIterT; - - typedef llvm::DenseSet<const Atom *> AtomSetT; - - DefaultLayout(ELFLinkingContext &context) - : _context(context), _linkerScriptSema(context.linkerScriptSema()) {} - - /// \brief Return the section order for a input section - SectionOrder getSectionOrder(StringRef name, int32_t contentType, - int32_t contentPermissions) override; - - /// \brief Return the name of the input section by decoding the input - /// sectionChoice. - virtual StringRef getInputSectionName(const DefinedAtom *da) const; - - /// \brief Return the name of the output section from the input section. - virtual StringRef getOutputSectionName(StringRef archivePath, - StringRef memberPath, - StringRef inputSectionName) const; - - /// \brief Gets or creates a section. - AtomSection<ELFT> * - getSection(StringRef name, int32_t contentType, - DefinedAtom::ContentPermissions contentPermissions, - const DefinedAtom *da); - - /// \brief Gets the segment for a output section - virtual Layout::SegmentType getSegmentType(Section<ELFT> *section) const; - - /// \brief Returns true/false depending on whether the section has a Output - // segment or not - static bool hasOutputSegment(Section<ELFT> *section); - - // Adds an atom to the section - ErrorOr<const lld::AtomLayout *> addAtom(const Atom *atom) override; - - /// \brief Find an output Section given a section name. - OutputSection<ELFT> *findOutputSection(StringRef name) { - auto iter = _outputSectionMap.find(name); - if (iter == _outputSectionMap.end()) - return nullptr; - return iter->second; - } - - /// \brief find a absolute atom given a name - AbsoluteAtomIterT findAbsoluteAtom(StringRef name) { - return std::find_if(_absoluteAtoms.begin(), _absoluteAtoms.end(), - FindByName(name)); - } - - // Output sections with the same name into a OutputSection - void createOutputSections(); - - /// \brief Sort the sections by their order as defined by the layout, - /// preparing all sections to be assigned to a segment. - virtual void sortInputSections(); - - /// \brief Add extra chunks to a segment just before including the input - /// section given by <archivePath, memberPath, sectionName>. This - /// is used to add linker script expressions before each section. - virtual void addExtraChunksToSegment(Segment<ELFT> *segment, - StringRef archivePath, - StringRef memberPath, - StringRef sectionName); - - void assignSectionsToSegments() override; - - void assignVirtualAddress() override; - - void assignFileOffsetsForMiscSections(); - - range<AbsoluteAtomIterT> absoluteAtoms() { return _absoluteAtoms; } - - void addSection(Chunk<ELFT> *c) { _sections.push_back(c); } - - void finalize() { - ScopedTask task(getDefaultDomain(), "Finalize layout"); - for (auto &si : _sections) - si->finalize(); - } - - void doPreFlight() { - for (auto &si : _sections) - si->doPreFlight(); - } - - const AtomLayout *findAtomLayoutByName(StringRef name) const override { - for (auto sec : _sections) - if (auto section = dyn_cast<Section<ELFT>>(sec)) - if (auto *al = section->findAtomLayoutByName(name)) - return al; - return nullptr; - } - - void setHeader(ELFHeader<ELFT> *elfHeader) { _elfHeader = elfHeader; } - - void setProgramHeader(ProgramHeader<ELFT> *p) { - _programHeader = p; - } - - range<OutputSectionIter> outputSections() { return _outputSections; } - - range<ChunkIter> sections() { return _sections; } - - range<SegmentIter> segments() { return _segments; } - - ELFHeader<ELFT> *getHeader() { return _elfHeader; } - - bool hasDynamicRelocationTable() const { return !!_dynamicRelocationTable; } - - bool hasPLTRelocationTable() const { return !!_pltRelocationTable; } - - /// \brief Get or create the dynamic relocation table. All relocations in this - /// table are processed at startup. - RelocationTable<ELFT> *getDynamicRelocationTable() { - if (!_dynamicRelocationTable) { - _dynamicRelocationTable = std::move(createRelocationTable( - _context.isRelaOutputFormat() ? ".rela.dyn" : ".rel.dyn", - ORDER_DYNAMIC_RELOCS)); - addSection(_dynamicRelocationTable.get()); - } - return _dynamicRelocationTable.get(); - } - - /// \brief Get or create the PLT relocation table. Referenced by DT_JMPREL. - RelocationTable<ELFT> *getPLTRelocationTable() { - if (!_pltRelocationTable) { - _pltRelocationTable = std::move(createRelocationTable( - _context.isRelaOutputFormat() ? ".rela.plt" : ".rel.plt", - ORDER_DYNAMIC_PLT_RELOCS)); - addSection(_pltRelocationTable.get()); - } - return _pltRelocationTable.get(); - } - - uint64_t getTLSSize() const { - for (const auto &phdr : *_programHeader) - if (phdr->p_type == llvm::ELF::PT_TLS) - return phdr->p_memsz; - return 0; - } - - bool isReferencedByDefinedAtom(const Atom *a) const { - return _referencedDynAtoms.count(a); - } - - bool isCopied(const SharedLibraryAtom *sla) const { - return _copiedDynSymNames.count(sla->name()); - } - - /// \brief Handle SORT_BY_PRIORITY. - void sortOutputSectionByPriority(StringRef outputSectionName, - StringRef prefix); - -protected: - /// \brief TargetLayouts may use these functions to reorder the input sections - /// in a order defined by their ABI. - virtual void finalizeOutputSectionLayout() {} - - /// \brief Allocate a new section. - virtual AtomSection<ELFT> *createSection( - StringRef name, int32_t contentType, - DefinedAtom::ContentPermissions contentPermissions, - SectionOrder sectionOrder); - - /// \brief Create a new relocation table. - virtual unique_bump_ptr<RelocationTable<ELFT>> - createRelocationTable(StringRef name, int32_t order) { - return unique_bump_ptr<RelocationTable<ELFT>>( - new (_allocator) RelocationTable<ELFT>(_context, name, order)); - } - -private: - /// Helper function that returns the priority value from an input section. - uint32_t getPriorityFromSectionName(StringRef sectionName) const; - -protected: - llvm::BumpPtrAllocator _allocator; - SectionMapT _sectionMap; - OutputSectionMapT _outputSectionMap; - AdditionalSegmentMapT _additionalSegmentMap; - SegmentMapT _segmentMap; - std::vector<Chunk<ELFT> *> _sections; - std::vector<Segment<ELFT> *> _segments; - std::vector<OutputSection<ELFT> *> _outputSections; - ELFHeader<ELFT> *_elfHeader; - ProgramHeader<ELFT> *_programHeader; - unique_bump_ptr<RelocationTable<ELFT>> _dynamicRelocationTable; - unique_bump_ptr<RelocationTable<ELFT>> _pltRelocationTable; - std::vector<lld::AtomLayout *> _absoluteAtoms; - AtomSetT _referencedDynAtoms; - llvm::StringSet<> _copiedDynSymNames; - ELFLinkingContext &_context; - script::Sema &_linkerScriptSema; -}; - -template <class ELFT> -Layout::SectionOrder DefaultLayout<ELFT>::getSectionOrder( - StringRef name, int32_t contentType, int32_t contentPermissions) { - switch (contentType) { - case DefinedAtom::typeResolver: - case DefinedAtom::typeCode: - return llvm::StringSwitch<Layout::SectionOrder>(name) - .StartsWith(".eh_frame_hdr", ORDER_EH_FRAMEHDR) - .StartsWith(".eh_frame", ORDER_EH_FRAME) - .StartsWith(".init", ORDER_INIT) - .StartsWith(".fini", ORDER_FINI) - .StartsWith(".hash", ORDER_HASH) - .Default(ORDER_TEXT); - - case DefinedAtom::typeConstant: - return ORDER_RODATA; - - case DefinedAtom::typeData: - case DefinedAtom::typeDataFast: - return llvm::StringSwitch<Layout::SectionOrder>(name) - .StartsWith(".init_array", ORDER_INIT_ARRAY) - .StartsWith(".fini_array", ORDER_FINI_ARRAY) - .StartsWith(".dynamic", ORDER_DYNAMIC) - .StartsWith(".ctors", ORDER_CTORS) - .StartsWith(".dtors", ORDER_DTORS) - .Default(ORDER_DATA); - - case DefinedAtom::typeZeroFill: - case DefinedAtom::typeZeroFillFast: - return ORDER_BSS; - - case DefinedAtom::typeGOT: - return llvm::StringSwitch<Layout::SectionOrder>(name) - .StartsWith(".got.plt", ORDER_GOT_PLT) - .Default(ORDER_GOT); - - case DefinedAtom::typeStub: - return ORDER_PLT; - - case DefinedAtom::typeRONote: - return ORDER_RO_NOTE; - - case DefinedAtom::typeRWNote: - return ORDER_RW_NOTE; - - case DefinedAtom::typeNoAlloc: - return ORDER_NOALLOC; - - case DefinedAtom::typeThreadData: - return ORDER_TDATA; - case DefinedAtom::typeThreadZeroFill: - return ORDER_TBSS; - default: - // If we get passed in a section push it to OTHER - if (contentPermissions == DefinedAtom::perm___) - return ORDER_OTHER; - - return ORDER_NOT_DEFINED; - } -} - -/// \brief This maps the input sections to the output section names -template <class ELFT> -StringRef -DefaultLayout<ELFT>::getInputSectionName(const DefinedAtom *da) const { - if (da->sectionChoice() == DefinedAtom::sectionBasedOnContent) { - switch (da->contentType()) { - case DefinedAtom::typeCode: - return ".text"; - case DefinedAtom::typeData: - return ".data"; - case DefinedAtom::typeConstant: - return ".rodata"; - case DefinedAtom::typeZeroFill: - return ".bss"; - case DefinedAtom::typeThreadData: - return ".tdata"; - case DefinedAtom::typeThreadZeroFill: - return ".tbss"; - default: - break; - } - } - return da->customSectionName(); -} - -/// \brief This maps the input sections to the output section names. -template <class ELFT> -StringRef -DefaultLayout<ELFT>::getOutputSectionName(StringRef archivePath, - StringRef memberPath, - StringRef inputSectionName) const { - StringRef outputSectionName; - if (_linkerScriptSema.hasLayoutCommands()) { - script::Sema::SectionKey key = {archivePath, memberPath, inputSectionName}; - outputSectionName = _linkerScriptSema.getOutputSection(key); - if (!outputSectionName.empty()) - return outputSectionName; - } - return llvm::StringSwitch<StringRef>(inputSectionName) - .StartsWith(".text", ".text") - .StartsWith(".ctors", ".ctors") - .StartsWith(".dtors", ".dtors") - .StartsWith(".rodata", ".rodata") - .StartsWith(".gcc_except_table", ".gcc_except_table") - .StartsWith(".data.rel.ro", ".data.rel.ro") - .StartsWith(".data.rel.local", ".data.rel.local") - .StartsWith(".data", ".data") - .StartsWith(".tdata", ".tdata") - .StartsWith(".tbss", ".tbss") - .StartsWith(".init_array", ".init_array") - .StartsWith(".fini_array", ".fini_array") - .Default(inputSectionName); -} - -/// \brief Gets the segment for a output section -template <class ELFT> -Layout::SegmentType DefaultLayout<ELFT>::getSegmentType( - Section<ELFT> *section) const { - - switch (section->order()) { - case ORDER_INTERP: - return llvm::ELF::PT_INTERP; - - case ORDER_TEXT: - case ORDER_HASH: - case ORDER_DYNAMIC_SYMBOLS: - case ORDER_DYNAMIC_STRINGS: - case ORDER_DYNAMIC_RELOCS: - case ORDER_DYNAMIC_PLT_RELOCS: - case ORDER_REL: - case ORDER_INIT: - case ORDER_PLT: - case ORDER_FINI: - case ORDER_RODATA: - case ORDER_EH_FRAME: - case ORDER_CTORS: - case ORDER_DTORS: - return llvm::ELF::PT_LOAD; - - case ORDER_RO_NOTE: - case ORDER_RW_NOTE: - return llvm::ELF::PT_NOTE; - - case ORDER_DYNAMIC: - return llvm::ELF::PT_DYNAMIC; - - case ORDER_EH_FRAMEHDR: - return llvm::ELF::PT_GNU_EH_FRAME; - - case ORDER_GOT: - case ORDER_GOT_PLT: - case ORDER_DATA: - case ORDER_BSS: - case ORDER_INIT_ARRAY: - case ORDER_FINI_ARRAY: - return llvm::ELF::PT_LOAD; - - case ORDER_TDATA: - case ORDER_TBSS: - return llvm::ELF::PT_TLS; - - default: - return llvm::ELF::PT_NULL; - } -} - -template <class ELFT> -bool DefaultLayout<ELFT>::hasOutputSegment(Section<ELFT> *section) { - switch (section->order()) { - case ORDER_INTERP: - case ORDER_HASH: - case ORDER_DYNAMIC_SYMBOLS: - case ORDER_DYNAMIC_STRINGS: - case ORDER_DYNAMIC_RELOCS: - case ORDER_DYNAMIC_PLT_RELOCS: - case ORDER_REL: - case ORDER_INIT: - case ORDER_PLT: - case ORDER_TEXT: - case ORDER_FINI: - case ORDER_RODATA: - case ORDER_EH_FRAME: - case ORDER_EH_FRAMEHDR: - case ORDER_TDATA: - case ORDER_TBSS: - case ORDER_RO_NOTE: - case ORDER_RW_NOTE: - case ORDER_DYNAMIC: - case ORDER_CTORS: - case ORDER_DTORS: - case ORDER_GOT: - case ORDER_GOT_PLT: - case ORDER_DATA: - case ORDER_INIT_ARRAY: - case ORDER_FINI_ARRAY: - case ORDER_BSS: - case ORDER_NOALLOC: - return true; - default: - return section->hasOutputSegment(); - } -} - -template <class ELFT> -AtomSection<ELFT> *DefaultLayout<ELFT>::createSection( - StringRef sectionName, int32_t contentType, - DefinedAtom::ContentPermissions permissions, SectionOrder sectionOrder) { - return new (_allocator) AtomSection<ELFT>(_context, sectionName, contentType, - permissions, sectionOrder); -} - -template <class ELFT> -AtomSection<ELFT> * -DefaultLayout<ELFT>::getSection(StringRef sectionName, int32_t contentType, - DefinedAtom::ContentPermissions permissions, - const DefinedAtom *da) { - const SectionKey sectionKey(sectionName, permissions, da->file().path()); - SectionOrder sectionOrder = getSectionOrder(sectionName, contentType, permissions); - auto sec = _sectionMap.find(sectionKey); - if (sec != _sectionMap.end()) - return sec->second; - AtomSection<ELFT> *newSec = - createSection(sectionName, contentType, permissions, sectionOrder); - - newSec->setOutputSectionName(getOutputSectionName( - da->file().archivePath(), da->file().memberPath(), sectionName)); - newSec->setOrder(sectionOrder); - newSec->setArchiveNameOrPath(da->file().archivePath()); - newSec->setMemberNameOrPath(da->file().memberPath()); - _sections.push_back(newSec); - _sectionMap.insert(std::make_pair(sectionKey, newSec)); - return newSec; -} - -template <class ELFT> -ErrorOr<const lld::AtomLayout *> -DefaultLayout<ELFT>::addAtom(const Atom *atom) { - if (const DefinedAtom *definedAtom = dyn_cast<DefinedAtom>(atom)) { - // HACK: Ignore undefined atoms. We need to adjust the interface so that - // undefined atoms can still be included in the output symbol table for - // -noinhibit-exec. - if (definedAtom->contentType() == DefinedAtom::typeUnknown) - return make_error_code(llvm::errc::invalid_argument); - const DefinedAtom::ContentPermissions permissions = - definedAtom->permissions(); - const DefinedAtom::ContentType contentType = definedAtom->contentType(); - - StringRef sectionName = getInputSectionName(definedAtom); - AtomSection<ELFT> *section = - getSection(sectionName, contentType, permissions, definedAtom); - - // Add runtime relocations to the .rela section. - for (const auto &reloc : *definedAtom) { - bool isLocalReloc = true; - if (_context.isDynamicRelocation(*reloc)) { - getDynamicRelocationTable()->addRelocation(*definedAtom, *reloc); - isLocalReloc = false; - } else if (_context.isPLTRelocation(*reloc)) { - getPLTRelocationTable()->addRelocation(*definedAtom, *reloc); - isLocalReloc = false; - } - - if (!reloc->target()) - continue; - - //Ignore undefined atoms that are not target of dynamic relocations - if (isa<UndefinedAtom>(reloc->target()) && isLocalReloc) - continue; - - if (_context.isCopyRelocation(*reloc)) { - _copiedDynSymNames.insert(definedAtom->name()); - continue; - } - - _referencedDynAtoms.insert(reloc->target()); - } - - return section->appendAtom(atom); - } else if (const AbsoluteAtom *absoluteAtom = dyn_cast<AbsoluteAtom>(atom)) { - // Absolute atoms are not part of any section, they are global for the whole - // link - _absoluteAtoms.push_back(new (_allocator) - lld::AtomLayout(absoluteAtom, 0, absoluteAtom->value())); - return _absoluteAtoms.back(); - } else { - llvm_unreachable("Only absolute / defined atoms can be added here"); - } -} - -/// Output sections with the same name into a OutputSection -template <class ELFT> void DefaultLayout<ELFT>::createOutputSections() { - OutputSection<ELFT> *outputSection; - - for (auto &si : _sections) { - Section<ELFT> *section = dyn_cast<Section<ELFT>>(si); - if (!section) - continue; - const std::pair<StringRef, OutputSection<ELFT> *> currentOutputSection( - section->outputSectionName(), nullptr); - std::pair<typename OutputSectionMapT::iterator, bool> outputSectionInsert( - _outputSectionMap.insert(currentOutputSection)); - if (!outputSectionInsert.second) { - outputSection = outputSectionInsert.first->second; - } else { - outputSection = new (_allocator.Allocate<OutputSection<ELFT>>()) - OutputSection<ELFT>(section->outputSectionName()); - _outputSections.push_back(outputSection); - outputSectionInsert.first->second = outputSection; - } - outputSection->appendSection(si); - } -} - -template <class ELFT> -uint32_t -DefaultLayout<ELFT>::getPriorityFromSectionName(StringRef sectionName) const { - StringRef priority = sectionName.drop_front().rsplit('.').second; - uint32_t prio; - if (priority.getAsInteger(10, prio)) - return std::numeric_limits<uint32_t>::max(); - return prio; -} - -template <class ELFT> -void DefaultLayout<ELFT>::sortOutputSectionByPriority( - StringRef outputSectionName, StringRef prefix) { - OutputSection<ELFT> *outputSection = findOutputSection(outputSectionName); - if (!outputSection) - return; - - auto sections = outputSection->sections(); - - std::sort(sections.begin(), sections.end(), - [&](Chunk<ELFT> *lhs, Chunk<ELFT> *rhs) { - Section<ELFT> *lhsSection = dyn_cast<Section<ELFT>>(lhs); - Section<ELFT> *rhsSection = dyn_cast<Section<ELFT>>(rhs); - if (!lhsSection || !rhsSection) - return false; - StringRef lhsSectionName = lhsSection->inputSectionName(); - StringRef rhsSectionName = rhsSection->inputSectionName(); - - if (!prefix.empty()) { - if (!lhsSectionName.startswith(prefix) || - !rhsSectionName.startswith(prefix)) - return false; - } - return getPriorityFromSectionName(lhsSectionName) < - getPriorityFromSectionName(rhsSectionName); - }); -} - -template <class ELFT> void DefaultLayout<ELFT>::assignSectionsToSegments() { - ScopedTask task(getDefaultDomain(), "assignSectionsToSegments"); - ELFLinkingContext::OutputMagic outputMagic = _context.getOutputMagic(); - // sort the sections by their order as defined by the layout - sortInputSections(); - - // Create output sections. - createOutputSections(); - - // Finalize output section layout. - finalizeOutputSectionLayout(); - - // Set the ordinal after sorting the sections - int ordinal = 1; - for (auto osi : _outputSections) { - osi->setOrdinal(ordinal); - for (auto ai : osi->sections()) { - ai->setOrdinal(ordinal); - } - ++ordinal; - } - for (auto osi : _outputSections) { - for (auto ai : osi->sections()) { - if (auto section = dyn_cast<Section<ELFT> >(ai)) { - if (!hasOutputSegment(section)) - continue; - - osi->setLoadableSection(section->isLoadableSection()); - - // Get the segment type for the section - int64_t segmentType = getSegmentType(section); - - osi->setHasSegment(); - section->setSegmentType(segmentType); - StringRef segmentName = section->segmentKindToStr(); - - int64_t lookupSectionFlag = osi->flags(); - if ((!(lookupSectionFlag & llvm::ELF::SHF_WRITE)) && - (_context.mergeRODataToTextSegment())) - lookupSectionFlag &= ~llvm::ELF::SHF_EXECINSTR; - - // Merge string sections into Data segment itself - lookupSectionFlag &= ~(llvm::ELF::SHF_STRINGS | llvm::ELF::SHF_MERGE); - - // Merge the TLS section into the DATA segment itself - lookupSectionFlag &= ~(llvm::ELF::SHF_TLS); - - Segment<ELFT> *segment; - // We need a separate segment for sections that don't have - // the segment type to be PT_LOAD - if (segmentType != llvm::ELF::PT_LOAD) { - const AdditionalSegmentKey key(segmentType, lookupSectionFlag); - const std::pair<AdditionalSegmentKey, Segment<ELFT> *> - additionalSegment(key, nullptr); - std::pair<typename AdditionalSegmentMapT::iterator, bool> - additionalSegmentInsert( - _additionalSegmentMap.insert(additionalSegment)); - if (!additionalSegmentInsert.second) { - segment = additionalSegmentInsert.first->second; - } else { - segment = new (_allocator) - Segment<ELFT>(_context, segmentName, segmentType); - additionalSegmentInsert.first->second = segment; - _segments.push_back(segment); - } - segment->append(section); - } - if (segmentType == llvm::ELF::PT_NULL) - continue; - - // If the output magic is set to OutputMagic::NMAGIC or - // OutputMagic::OMAGIC, Place the data alongside text in one single - // segment - if (outputMagic == ELFLinkingContext::OutputMagic::NMAGIC || - outputMagic == ELFLinkingContext::OutputMagic::OMAGIC) - lookupSectionFlag = llvm::ELF::SHF_EXECINSTR | llvm::ELF::SHF_ALLOC | - llvm::ELF::SHF_WRITE; - - // Use the flags of the merged Section for the segment - const SegmentKey key("PT_LOAD", lookupSectionFlag); - const std::pair<SegmentKey, Segment<ELFT> *> currentSegment(key, - nullptr); - std::pair<typename SegmentMapT::iterator, bool> segmentInsert( - _segmentMap.insert(currentSegment)); - if (!segmentInsert.second) { - segment = segmentInsert.first->second; - } else { - segment = new (_allocator) - Segment<ELFT>(_context, "PT_LOAD", llvm::ELF::PT_LOAD); - segmentInsert.first->second = segment; - _segments.push_back(segment); - } - // Insert chunks with linker script expressions that occur at this - // point, just before appending a new input section - addExtraChunksToSegment(segment, section->archivePath(), - section->memberPath(), - section->inputSectionName()); - segment->append(section); - } - } - } - if (_context.isDynamic() && !_context.isDynamicLibrary()) { - Segment<ELFT> *segment = - new (_allocator) ProgramHeaderSegment<ELFT>(_context); - _segments.push_back(segment); - segment->append(_elfHeader); - segment->append(_programHeader); - } -} - -template<class ELFT> -void -DefaultLayout<ELFT>::assignVirtualAddress() { - if (_segments.empty()) - return; - - std::sort(_segments.begin(), _segments.end(), Segment<ELFT>::compareSegments); - - uint64_t baseAddress = _context.getBaseAddress(); - - // HACK: This is a super dirty hack. The elf header and program header are - // not part of a section, but we need them to be loaded at the base address - // so that AT_PHDR is set correctly by the loader and so they are accessible - // at runtime. To do this we simply prepend them to the first loadable Segment - // and let the layout logic take care of it. - Segment<ELFT> *firstLoadSegment = nullptr; - for (auto si : _segments) { - if (si->segmentType() == llvm::ELF::PT_LOAD) { - firstLoadSegment = si; - si->firstSection()->setAlign(si->alignment()); - break; - } - } - assert(firstLoadSegment != nullptr && "No loadable segment!"); - firstLoadSegment->prepend(_programHeader); - firstLoadSegment->prepend(_elfHeader); - bool newSegmentHeaderAdded = true; - bool virtualAddressAssigned = false; - bool fileOffsetAssigned = false; - while (true) { - for (auto si : _segments) { - si->finalize(); - // Don't add PT_NULL segments into the program header - if (si->segmentType() != llvm::ELF::PT_NULL) - newSegmentHeaderAdded = _programHeader->addSegment(si); - } - if (!newSegmentHeaderAdded && virtualAddressAssigned) - break; - uint64_t address = baseAddress; - // start assigning virtual addresses - for (auto &si : _segments) { - if ((si->segmentType() != llvm::ELF::PT_LOAD) && - (si->segmentType() != llvm::ELF::PT_NULL)) - continue; - - if (si->segmentType() == llvm::ELF::PT_NULL) { - si->assignVirtualAddress(0 /*non loadable*/); - } else { - if (virtualAddressAssigned && (address != baseAddress) && - (address == si->virtualAddr())) - break; - si->assignVirtualAddress(address); - } - address = si->virtualAddr() + si->memSize(); - } - uint64_t baseFileOffset = 0; - uint64_t fileoffset = baseFileOffset; - for (auto &si : _segments) { - if ((si->segmentType() != llvm::ELF::PT_LOAD) && - (si->segmentType() != llvm::ELF::PT_NULL)) - continue; - if (fileOffsetAssigned && (fileoffset != baseFileOffset) && - (fileoffset == si->fileOffset())) - break; - si->assignFileOffsets(fileoffset); - fileoffset = si->fileOffset() + si->fileSize(); - } - virtualAddressAssigned = true; - fileOffsetAssigned = true; - _programHeader->resetProgramHeaders(); - } - Section<ELFT> *section; - // Fix the offsets of all the atoms within a section - for (auto &si : _sections) { - section = dyn_cast<Section<ELFT>>(si); - if (section && DefaultLayout<ELFT>::hasOutputSegment(section)) - section->assignFileOffsets(section->fileOffset()); - } - // Set the size of the merged Sections - for (auto osi : _outputSections) { - uint64_t sectionfileoffset = 0; - uint64_t startFileOffset = 0; - uint64_t sectionsize = 0; - bool isFirstSection = true; - for (auto si : osi->sections()) { - if (isFirstSection) { - startFileOffset = si->fileOffset(); - isFirstSection = false; - } - sectionfileoffset = si->fileOffset(); - sectionsize = si->fileSize(); - } - sectionsize = (sectionfileoffset - startFileOffset) + sectionsize; - osi->setFileOffset(startFileOffset); - osi->setSize(sectionsize); - } - // Set the virtual addr of the merged Sections - for (auto osi : _outputSections) { - uint64_t sectionstartaddr = 0; - uint64_t startaddr = 0; - uint64_t sectionsize = 0; - bool isFirstSection = true; - for (auto si : osi->sections()) { - if (isFirstSection) { - startaddr = si->virtualAddr(); - isFirstSection = false; - } - sectionstartaddr = si->virtualAddr(); - sectionsize = si->memSize(); - } - sectionsize = (sectionstartaddr - startaddr) + sectionsize; - osi->setMemSize(sectionsize); - osi->setAddr(startaddr); - } -} - -template <class ELFT> -void DefaultLayout<ELFT>::assignFileOffsetsForMiscSections() { - uint64_t fileoffset = 0; - uint64_t size = 0; - for (auto si : _segments) { - // Don't calculate offsets from non loadable segments - if ((si->segmentType() != llvm::ELF::PT_LOAD) && - (si->segmentType() != llvm::ELF::PT_NULL)) - continue; - fileoffset = si->fileOffset(); - size = si->fileSize(); - } - fileoffset = fileoffset + size; - Section<ELFT> *section; - for (auto si : _sections) { - section = dyn_cast<Section<ELFT>>(si); - if (section && DefaultLayout<ELFT>::hasOutputSegment(section)) - continue; - fileoffset = llvm::RoundUpToAlignment(fileoffset, si->alignment()); - si->setFileOffset(fileoffset); - si->setVirtualAddr(0); - fileoffset += si->fileSize(); - } -} - -template <class ELFT> void DefaultLayout<ELFT>::sortInputSections() { - // First, sort according to default layout's order - std::stable_sort( - _sections.begin(), _sections.end(), - [](Chunk<ELFT> *A, Chunk<ELFT> *B) { return A->order() < B->order(); }); - - if (!_linkerScriptSema.hasLayoutCommands()) - return; - - // Sort the sections by their order as defined by the linker script - std::stable_sort(this->_sections.begin(), this->_sections.end(), - [this](Chunk<ELFT> *A, Chunk<ELFT> *B) { - auto *a = dyn_cast<Section<ELFT>>(A); - auto *b = dyn_cast<Section<ELFT>>(B); - - if (a == nullptr) - return false; - if (b == nullptr) - return true; - - return _linkerScriptSema.less( - {a->archivePath(), a->memberPath(), - a->inputSectionName()}, - {b->archivePath(), b->memberPath(), - b->inputSectionName()}); - }); - // Now try to arrange sections with no mapping rules to sections with - // similar content - auto p = this->_sections.begin(); - // Find first section that has no assigned rule id - while (p != this->_sections.end()) { - auto *sect = dyn_cast<AtomSection<ELFT>>(*p); - if (!sect) - break; - - if (!_linkerScriptSema.hasMapping({sect->archivePath(), - sect->memberPath(), - sect->inputSectionName()})) - break; - - ++p; - } - // For all sections that have no assigned rule id, try to move them near a - // section with similar contents - if (p != this->_sections.begin()) { - for (; p != this->_sections.end(); ++p) { - auto q = p; - --q; - while (q != this->_sections.begin() && - (*q)->getContentType() != (*p)->getContentType()) - --q; - if ((*q)->getContentType() != (*p)->getContentType()) - continue; - ++q; - for (auto i = p; i != q;) { - auto next = i--; - std::iter_swap(i, next); - } - } - } -} - -template <class ELFT> -void DefaultLayout<ELFT>::addExtraChunksToSegment(Segment<ELFT> *segment, - StringRef archivePath, - StringRef memberPath, - StringRef sectionName) { - if (!_linkerScriptSema.hasLayoutCommands()) - return; - - std::vector<const script::SymbolAssignment *> exprs = - _linkerScriptSema.getExprs({archivePath, memberPath, sectionName}); - for (auto expr : exprs) { - auto expChunk = - new (this->_allocator) ExpressionChunk<ELFT>(this->_context, expr); - segment->append(expChunk); - } -} - -} // end namespace elf -} // end namespace lld - -#endif |