| //===- tools/dsymutil/DwarfLinker.cpp - Dwarf debug info linker -----------===// |
| // |
| // 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 "DwarfLinker.h" |
| #include "BinaryHolder.h" |
| #include "DebugMap.h" |
| #include "DeclContext.h" |
| #include "DwarfStreamer.h" |
| #include "MachOUtils.h" |
| #include "NonRelocatableStringpool.h" |
| #include "dsymutil.h" |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/ADT/BitVector.h" |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/ADT/DenseMapInfo.h" |
| #include "llvm/ADT/DenseSet.h" |
| #include "llvm/ADT/FoldingSet.h" |
| #include "llvm/ADT/Hashing.h" |
| #include "llvm/ADT/IntervalMap.h" |
| #include "llvm/ADT/None.h" |
| #include "llvm/ADT/Optional.h" |
| #include "llvm/ADT/PointerIntPair.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/SmallString.h" |
| #include "llvm/ADT/StringMap.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/ADT/Triple.h" |
| #include "llvm/ADT/Twine.h" |
| #include "llvm/BinaryFormat/Dwarf.h" |
| #include "llvm/BinaryFormat/MachO.h" |
| #include "llvm/CodeGen/AccelTable.h" |
| #include "llvm/CodeGen/AsmPrinter.h" |
| #include "llvm/CodeGen/DIE.h" |
| #include "llvm/Config/config.h" |
| #include "llvm/DebugInfo/DIContext.h" |
| #include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h" |
| #include "llvm/DebugInfo/DWARF/DWARFContext.h" |
| #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h" |
| #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h" |
| #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h" |
| #include "llvm/DebugInfo/DWARF/DWARFDie.h" |
| #include "llvm/DebugInfo/DWARF/DWARFFormValue.h" |
| #include "llvm/DebugInfo/DWARF/DWARFSection.h" |
| #include "llvm/DebugInfo/DWARF/DWARFUnit.h" |
| #include "llvm/MC/MCAsmBackend.h" |
| #include "llvm/MC/MCAsmInfo.h" |
| #include "llvm/MC/MCCodeEmitter.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCDwarf.h" |
| #include "llvm/MC/MCInstrInfo.h" |
| #include "llvm/MC/MCObjectFileInfo.h" |
| #include "llvm/MC/MCObjectWriter.h" |
| #include "llvm/MC/MCRegisterInfo.h" |
| #include "llvm/MC/MCSection.h" |
| #include "llvm/MC/MCStreamer.h" |
| #include "llvm/MC/MCSubtargetInfo.h" |
| #include "llvm/MC/MCTargetOptions.h" |
| #include "llvm/Object/MachO.h" |
| #include "llvm/Object/ObjectFile.h" |
| #include "llvm/Object/SymbolicFile.h" |
| #include "llvm/Support/Allocator.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/Compiler.h" |
| #include "llvm/Support/DJB.h" |
| #include "llvm/Support/DataExtractor.h" |
| #include "llvm/Support/Error.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/ErrorOr.h" |
| #include "llvm/Support/FileSystem.h" |
| #include "llvm/Support/Format.h" |
| #include "llvm/Support/LEB128.h" |
| #include "llvm/Support/MathExtras.h" |
| #include "llvm/Support/MemoryBuffer.h" |
| #include "llvm/Support/Path.h" |
| #include "llvm/Support/TargetRegistry.h" |
| #include "llvm/Support/ThreadPool.h" |
| #include "llvm/Support/ToolOutputFile.h" |
| #include "llvm/Support/WithColor.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Target/TargetMachine.h" |
| #include "llvm/Target/TargetOptions.h" |
| #include <algorithm> |
| #include <cassert> |
| #include <cinttypes> |
| #include <climits> |
| #include <cstdint> |
| #include <cstdlib> |
| #include <cstring> |
| #include <limits> |
| #include <map> |
| #include <memory> |
| #include <string> |
| #include <system_error> |
| #include <tuple> |
| #include <utility> |
| #include <vector> |
| |
| namespace llvm { |
| namespace dsymutil { |
| |
| /// Similar to DWARFUnitSection::getUnitForOffset(), but returning our |
| /// CompileUnit object instead. |
| static CompileUnit *getUnitForOffset(const UnitListTy &Units, unsigned Offset) { |
| auto CU = std::upper_bound( |
| Units.begin(), Units.end(), Offset, |
| [](uint32_t LHS, const std::unique_ptr<CompileUnit> &RHS) { |
| return LHS < RHS->getOrigUnit().getNextUnitOffset(); |
| }); |
| return CU != Units.end() ? CU->get() : nullptr; |
| } |
| |
| /// Resolve the DIE attribute reference that has been extracted in \p RefValue. |
| /// The resulting DIE might be in another CompileUnit which is stored into \p |
| /// ReferencedCU. \returns null if resolving fails for any reason. |
| static DWARFDie resolveDIEReference(const DwarfLinker &Linker, |
| const DebugMapObject &DMO, |
| const UnitListTy &Units, |
| const DWARFFormValue &RefValue, |
| const DWARFDie &DIE, CompileUnit *&RefCU) { |
| assert(RefValue.isFormClass(DWARFFormValue::FC_Reference)); |
| uint64_t RefOffset = *RefValue.getAsReference(); |
| if ((RefCU = getUnitForOffset(Units, RefOffset))) |
| if (const auto RefDie = RefCU->getOrigUnit().getDIEForOffset(RefOffset)) { |
| // In a file with broken references, an attribute might point to a NULL |
| // DIE. |
| if (!RefDie.isNULL()) |
| return RefDie; |
| } |
| |
| Linker.reportWarning("could not find referenced DIE", DMO, &DIE); |
| return DWARFDie(); |
| } |
| |
| /// \returns whether the passed \a Attr type might contain a DIE reference |
| /// suitable for ODR uniquing. |
| static bool isODRAttribute(uint16_t Attr) { |
| switch (Attr) { |
| default: |
| return false; |
| case dwarf::DW_AT_type: |
| case dwarf::DW_AT_containing_type: |
| case dwarf::DW_AT_specification: |
| case dwarf::DW_AT_abstract_origin: |
| case dwarf::DW_AT_import: |
| return true; |
| } |
| llvm_unreachable("Improper attribute."); |
| } |
| |
| static bool isTypeTag(uint16_t Tag) { |
| switch (Tag) { |
| case dwarf::DW_TAG_array_type: |
| case dwarf::DW_TAG_class_type: |
| case dwarf::DW_TAG_enumeration_type: |
| case dwarf::DW_TAG_pointer_type: |
| case dwarf::DW_TAG_reference_type: |
| case dwarf::DW_TAG_string_type: |
| case dwarf::DW_TAG_structure_type: |
| case dwarf::DW_TAG_subroutine_type: |
| case dwarf::DW_TAG_typedef: |
| case dwarf::DW_TAG_union_type: |
| case dwarf::DW_TAG_ptr_to_member_type: |
| case dwarf::DW_TAG_set_type: |
| case dwarf::DW_TAG_subrange_type: |
| case dwarf::DW_TAG_base_type: |
| case dwarf::DW_TAG_const_type: |
| case dwarf::DW_TAG_constant: |
| case dwarf::DW_TAG_file_type: |
| case dwarf::DW_TAG_namelist: |
| case dwarf::DW_TAG_packed_type: |
| case dwarf::DW_TAG_volatile_type: |
| case dwarf::DW_TAG_restrict_type: |
| case dwarf::DW_TAG_atomic_type: |
| case dwarf::DW_TAG_interface_type: |
| case dwarf::DW_TAG_unspecified_type: |
| case dwarf::DW_TAG_shared_type: |
| return true; |
| default: |
| break; |
| } |
| return false; |
| } |
| |
| bool DwarfLinker::DIECloner::getDIENames(const DWARFDie &Die, |
| AttributesInfo &Info, |
| OffsetsStringPool &StringPool, |
| bool StripTemplate) { |
| // This function will be called on DIEs having low_pcs and |
| // ranges. As getting the name might be more expansive, filter out |
| // blocks directly. |
| if (Die.getTag() == dwarf::DW_TAG_lexical_block) |
| return false; |
| |
| // FIXME: a bit wasteful as the first getName might return the |
| // short name. |
| if (!Info.MangledName) |
| if (const char *MangledName = Die.getName(DINameKind::LinkageName)) |
| Info.MangledName = StringPool.getEntry(MangledName); |
| |
| if (!Info.Name) |
| if (const char *Name = Die.getName(DINameKind::ShortName)) |
| Info.Name = StringPool.getEntry(Name); |
| |
| if (StripTemplate && Info.Name && Info.MangledName != Info.Name) { |
| // FIXME: dsymutil compatibility. This is wrong for operator< |
| auto Split = Info.Name.getString().split('<'); |
| if (!Split.second.empty()) |
| Info.NameWithoutTemplate = StringPool.getEntry(Split.first); |
| } |
| |
| return Info.Name || Info.MangledName; |
| } |
| |
| /// Report a warning to the user, optionally including information about a |
| /// specific \p DIE related to the warning. |
| void DwarfLinker::reportWarning(const Twine &Warning, const DebugMapObject &DMO, |
| const DWARFDie *DIE) const { |
| StringRef Context = DMO.getObjectFilename(); |
| warn(Warning, Context); |
| |
| if (!Options.Verbose || !DIE) |
| return; |
| |
| DIDumpOptions DumpOpts; |
| DumpOpts.RecurseDepth = 0; |
| DumpOpts.Verbose = Options.Verbose; |
| |
| WithColor::note() << " in DIE:\n"; |
| DIE->dump(errs(), 6 /* Indent */, DumpOpts); |
| } |
| |
| bool DwarfLinker::createStreamer(const Triple &TheTriple, |
| raw_fd_ostream &OutFile) { |
| if (Options.NoOutput) |
| return true; |
| |
| Streamer = llvm::make_unique<DwarfStreamer>(OutFile, Options); |
| return Streamer->init(TheTriple); |
| } |
| |
| /// Recursive helper to build the global DeclContext information and |
| /// gather the child->parent relationships in the original compile unit. |
| /// |
| /// \return true when this DIE and all of its children are only |
| /// forward declarations to types defined in external clang modules |
| /// (i.e., forward declarations that are children of a DW_TAG_module). |
| static bool analyzeContextInfo(const DWARFDie &DIE, unsigned ParentIdx, |
| CompileUnit &CU, DeclContext *CurrentDeclContext, |
| UniquingStringPool &StringPool, |
| DeclContextTree &Contexts, |
| uint64_t ModulesEndOffset, |
| bool InImportedModule = false) { |
| unsigned MyIdx = CU.getOrigUnit().getDIEIndex(DIE); |
| CompileUnit::DIEInfo &Info = CU.getInfo(MyIdx); |
| |
| // Clang imposes an ODR on modules(!) regardless of the language: |
| // "The module-id should consist of only a single identifier, |
| // which provides the name of the module being defined. Each |
| // module shall have a single definition." |
| // |
| // This does not extend to the types inside the modules: |
| // "[I]n C, this implies that if two structs are defined in |
| // different submodules with the same name, those two types are |
| // distinct types (but may be compatible types if their |
| // definitions match)." |
| // |
| // We treat non-C++ modules like namespaces for this reason. |
| if (DIE.getTag() == dwarf::DW_TAG_module && ParentIdx == 0 && |
| dwarf::toString(DIE.find(dwarf::DW_AT_name), "") != |
| CU.getClangModuleName()) { |
| InImportedModule = true; |
| } |
| |
| Info.ParentIdx = ParentIdx; |
| bool InClangModule = CU.isClangModule() || InImportedModule; |
| if (CU.hasODR() || InClangModule) { |
| if (CurrentDeclContext) { |
| auto PtrInvalidPair = Contexts.getChildDeclContext( |
| *CurrentDeclContext, DIE, CU, StringPool, InClangModule); |
| CurrentDeclContext = PtrInvalidPair.getPointer(); |
| Info.Ctxt = |
| PtrInvalidPair.getInt() ? nullptr : PtrInvalidPair.getPointer(); |
| if (Info.Ctxt) |
| Info.Ctxt->setDefinedInClangModule(InClangModule); |
| } else |
| Info.Ctxt = CurrentDeclContext = nullptr; |
| } |
| |
| Info.Prune = InImportedModule; |
| if (DIE.hasChildren()) |
| for (auto Child : DIE.children()) |
| Info.Prune &= |
| analyzeContextInfo(Child, MyIdx, CU, CurrentDeclContext, StringPool, |
| Contexts, ModulesEndOffset, InImportedModule); |
| |
| // Prune this DIE if it is either a forward declaration inside a |
| // DW_TAG_module or a DW_TAG_module that contains nothing but |
| // forward declarations. |
| Info.Prune &= (DIE.getTag() == dwarf::DW_TAG_module) || |
| (isTypeTag(DIE.getTag()) && |
| dwarf::toUnsigned(DIE.find(dwarf::DW_AT_declaration), 0)); |
| |
| // Only prune forward declarations inside a DW_TAG_module for which a |
| // definition exists elsewhere. |
| if (ModulesEndOffset == 0) |
| Info.Prune &= Info.Ctxt && Info.Ctxt->getCanonicalDIEOffset(); |
| else |
| Info.Prune &= Info.Ctxt && Info.Ctxt->getCanonicalDIEOffset() > 0 && |
| Info.Ctxt->getCanonicalDIEOffset() <= ModulesEndOffset; |
| |
| return Info.Prune; |
| } // namespace dsymutil |
| |
| static bool dieNeedsChildrenToBeMeaningful(uint32_t Tag) { |
| switch (Tag) { |
| default: |
| return false; |
| case dwarf::DW_TAG_subprogram: |
| case dwarf::DW_TAG_lexical_block: |
| case dwarf::DW_TAG_subroutine_type: |
| case dwarf::DW_TAG_structure_type: |
| case dwarf::DW_TAG_class_type: |
| case dwarf::DW_TAG_union_type: |
| return true; |
| } |
| llvm_unreachable("Invalid Tag"); |
| } |
| |
| void DwarfLinker::startDebugObject(LinkContext &Context) { |
| // Iterate over the debug map entries and put all the ones that are |
| // functions (because they have a size) into the Ranges map. This map is |
| // very similar to the FunctionRanges that are stored in each unit, with 2 |
| // notable differences: |
| // |
| // 1. Obviously this one is global, while the other ones are per-unit. |
| // |
| // 2. This one contains not only the functions described in the DIE |
| // tree, but also the ones that are only in the debug map. |
| // |
| // The latter information is required to reproduce dsymutil's logic while |
| // linking line tables. The cases where this information matters look like |
| // bugs that need to be investigated, but for now we need to reproduce |
| // dsymutil's behavior. |
| // FIXME: Once we understood exactly if that information is needed, |
| // maybe totally remove this (or try to use it to do a real |
| // -gline-tables-only on Darwin. |
| for (const auto &Entry : Context.DMO.symbols()) { |
| const auto &Mapping = Entry.getValue(); |
| if (Mapping.Size && Mapping.ObjectAddress) |
| Context.Ranges[*Mapping.ObjectAddress] = DebugMapObjectRange( |
| *Mapping.ObjectAddress + Mapping.Size, |
| int64_t(Mapping.BinaryAddress) - *Mapping.ObjectAddress); |
| } |
| } |
| |
| void DwarfLinker::endDebugObject(LinkContext &Context) { |
| Context.Clear(); |
| |
| for (auto I = DIEBlocks.begin(), E = DIEBlocks.end(); I != E; ++I) |
| (*I)->~DIEBlock(); |
| for (auto I = DIELocs.begin(), E = DIELocs.end(); I != E; ++I) |
| (*I)->~DIELoc(); |
| |
| DIEBlocks.clear(); |
| DIELocs.clear(); |
| DIEAlloc.Reset(); |
| } |
| |
| static bool isMachOPairedReloc(uint64_t RelocType, uint64_t Arch) { |
| switch (Arch) { |
| case Triple::x86: |
| return RelocType == MachO::GENERIC_RELOC_SECTDIFF || |
| RelocType == MachO::GENERIC_RELOC_LOCAL_SECTDIFF; |
| case Triple::x86_64: |
| return RelocType == MachO::X86_64_RELOC_SUBTRACTOR; |
| case Triple::arm: |
| case Triple::thumb: |
| return RelocType == MachO::ARM_RELOC_SECTDIFF || |
| RelocType == MachO::ARM_RELOC_LOCAL_SECTDIFF || |
| RelocType == MachO::ARM_RELOC_HALF || |
| RelocType == MachO::ARM_RELOC_HALF_SECTDIFF; |
| case Triple::aarch64: |
| return RelocType == MachO::ARM64_RELOC_SUBTRACTOR; |
| default: |
| return false; |
| } |
| } |
| |
| /// Iterate over the relocations of the given \p Section and |
| /// store the ones that correspond to debug map entries into the |
| /// ValidRelocs array. |
| void DwarfLinker::RelocationManager::findValidRelocsMachO( |
| const object::SectionRef &Section, const object::MachOObjectFile &Obj, |
| const DebugMapObject &DMO) { |
| StringRef Contents; |
| Section.getContents(Contents); |
| DataExtractor Data(Contents, Obj.isLittleEndian(), 0); |
| bool SkipNext = false; |
| |
| for (const object::RelocationRef &Reloc : Section.relocations()) { |
| if (SkipNext) { |
| SkipNext = false; |
| continue; |
| } |
| |
| object::DataRefImpl RelocDataRef = Reloc.getRawDataRefImpl(); |
| MachO::any_relocation_info MachOReloc = Obj.getRelocation(RelocDataRef); |
| |
| if (isMachOPairedReloc(Obj.getAnyRelocationType(MachOReloc), |
| Obj.getArch())) { |
| SkipNext = true; |
| Linker.reportWarning("unsupported relocation in debug_info section.", |
| DMO); |
| continue; |
| } |
| |
| unsigned RelocSize = 1 << Obj.getAnyRelocationLength(MachOReloc); |
| uint64_t Offset64 = Reloc.getOffset(); |
| if ((RelocSize != 4 && RelocSize != 8)) { |
| Linker.reportWarning("unsupported relocation in debug_info section.", |
| DMO); |
| continue; |
| } |
| uint32_t Offset = Offset64; |
| // Mach-o uses REL relocations, the addend is at the relocation offset. |
| uint64_t Addend = Data.getUnsigned(&Offset, RelocSize); |
| uint64_t SymAddress; |
| int64_t SymOffset; |
| |
| if (Obj.isRelocationScattered(MachOReloc)) { |
| // The address of the base symbol for scattered relocations is |
| // stored in the reloc itself. The actual addend will store the |
| // base address plus the offset. |
| SymAddress = Obj.getScatteredRelocationValue(MachOReloc); |
| SymOffset = int64_t(Addend) - SymAddress; |
| } else { |
| SymAddress = Addend; |
| SymOffset = 0; |
| } |
| |
| auto Sym = Reloc.getSymbol(); |
| if (Sym != Obj.symbol_end()) { |
| Expected<StringRef> SymbolName = Sym->getName(); |
| if (!SymbolName) { |
| consumeError(SymbolName.takeError()); |
| Linker.reportWarning("error getting relocation symbol name.", DMO); |
| continue; |
| } |
| if (const auto *Mapping = DMO.lookupSymbol(*SymbolName)) |
| ValidRelocs.emplace_back(Offset64, RelocSize, Addend, Mapping); |
| } else if (const auto *Mapping = DMO.lookupObjectAddress(SymAddress)) { |
| // Do not store the addend. The addend was the address of the symbol in |
| // the object file, the address in the binary that is stored in the debug |
| // map doesn't need to be offset. |
| ValidRelocs.emplace_back(Offset64, RelocSize, SymOffset, Mapping); |
| } |
| } |
| } |
| |
| /// Dispatch the valid relocation finding logic to the |
| /// appropriate handler depending on the object file format. |
| bool DwarfLinker::RelocationManager::findValidRelocs( |
| const object::SectionRef &Section, const object::ObjectFile &Obj, |
| const DebugMapObject &DMO) { |
| // Dispatch to the right handler depending on the file type. |
| if (auto *MachOObj = dyn_cast<object::MachOObjectFile>(&Obj)) |
| findValidRelocsMachO(Section, *MachOObj, DMO); |
| else |
| Linker.reportWarning( |
| Twine("unsupported object file type: ") + Obj.getFileName(), DMO); |
| |
| if (ValidRelocs.empty()) |
| return false; |
| |
| // Sort the relocations by offset. We will walk the DIEs linearly in |
| // the file, this allows us to just keep an index in the relocation |
| // array that we advance during our walk, rather than resorting to |
| // some associative container. See DwarfLinker::NextValidReloc. |
| llvm::sort(ValidRelocs); |
| return true; |
| } |
| |
| /// Look for relocations in the debug_info section that match |
| /// entries in the debug map. These relocations will drive the Dwarf |
| /// link by indicating which DIEs refer to symbols present in the |
| /// linked binary. |
| /// \returns whether there are any valid relocations in the debug info. |
| bool DwarfLinker::RelocationManager::findValidRelocsInDebugInfo( |
| const object::ObjectFile &Obj, const DebugMapObject &DMO) { |
| // Find the debug_info section. |
| for (const object::SectionRef &Section : Obj.sections()) { |
| StringRef SectionName; |
| Section.getName(SectionName); |
| SectionName = SectionName.substr(SectionName.find_first_not_of("._")); |
| if (SectionName != "debug_info") |
| continue; |
| return findValidRelocs(Section, Obj, DMO); |
| } |
| return false; |
| } |
| |
| /// Checks that there is a relocation against an actual debug |
| /// map entry between \p StartOffset and \p NextOffset. |
| /// |
| /// This function must be called with offsets in strictly ascending |
| /// order because it never looks back at relocations it already 'went past'. |
| /// \returns true and sets Info.InDebugMap if it is the case. |
| bool DwarfLinker::RelocationManager::hasValidRelocation( |
| uint32_t StartOffset, uint32_t EndOffset, CompileUnit::DIEInfo &Info) { |
| assert(NextValidReloc == 0 || |
| StartOffset > ValidRelocs[NextValidReloc - 1].Offset); |
| if (NextValidReloc >= ValidRelocs.size()) |
| return false; |
| |
| uint64_t RelocOffset = ValidRelocs[NextValidReloc].Offset; |
| |
| // We might need to skip some relocs that we didn't consider. For |
| // example the high_pc of a discarded DIE might contain a reloc that |
| // is in the list because it actually corresponds to the start of a |
| // function that is in the debug map. |
| while (RelocOffset < StartOffset && NextValidReloc < ValidRelocs.size() - 1) |
| RelocOffset = ValidRelocs[++NextValidReloc].Offset; |
| |
| if (RelocOffset < StartOffset || RelocOffset >= EndOffset) |
| return false; |
| |
| const auto &ValidReloc = ValidRelocs[NextValidReloc++]; |
| const auto &Mapping = ValidReloc.Mapping->getValue(); |
| uint64_t ObjectAddress = Mapping.ObjectAddress |
| ? uint64_t(*Mapping.ObjectAddress) |
| : std::numeric_limits<uint64_t>::max(); |
| if (Linker.Options.Verbose) |
| outs() << "Found valid debug map entry: " << ValidReloc.Mapping->getKey() |
| << " " |
| << format("\t%016" PRIx64 " => %016" PRIx64, ObjectAddress, |
| uint64_t(Mapping.BinaryAddress)); |
| |
| Info.AddrAdjust = int64_t(Mapping.BinaryAddress) + ValidReloc.Addend; |
| if (Mapping.ObjectAddress) |
| Info.AddrAdjust -= ObjectAddress; |
| Info.InDebugMap = true; |
| return true; |
| } |
| |
| /// Get the starting and ending (exclusive) offset for the |
| /// attribute with index \p Idx descibed by \p Abbrev. \p Offset is |
| /// supposed to point to the position of the first attribute described |
| /// by \p Abbrev. |
| /// \return [StartOffset, EndOffset) as a pair. |
| static std::pair<uint32_t, uint32_t> |
| getAttributeOffsets(const DWARFAbbreviationDeclaration *Abbrev, unsigned Idx, |
| unsigned Offset, const DWARFUnit &Unit) { |
| DataExtractor Data = Unit.getDebugInfoExtractor(); |
| |
| for (unsigned i = 0; i < Idx; ++i) |
| DWARFFormValue::skipValue(Abbrev->getFormByIndex(i), Data, &Offset, |
| Unit.getFormParams()); |
| |
| uint32_t End = Offset; |
| DWARFFormValue::skipValue(Abbrev->getFormByIndex(Idx), Data, &End, |
| Unit.getFormParams()); |
| |
| return std::make_pair(Offset, End); |
| } |
| |
| /// Check if a variable describing DIE should be kept. |
| /// \returns updated TraversalFlags. |
| unsigned DwarfLinker::shouldKeepVariableDIE(RelocationManager &RelocMgr, |
| const DWARFDie &DIE, |
| CompileUnit &Unit, |
| CompileUnit::DIEInfo &MyInfo, |
| unsigned Flags) { |
| const auto *Abbrev = DIE.getAbbreviationDeclarationPtr(); |
| |
| // Global variables with constant value can always be kept. |
| if (!(Flags & TF_InFunctionScope) && |
| Abbrev->findAttributeIndex(dwarf::DW_AT_const_value)) { |
| MyInfo.InDebugMap = true; |
| return Flags | TF_Keep; |
| } |
| |
| Optional<uint32_t> LocationIdx = |
| Abbrev->findAttributeIndex(dwarf::DW_AT_location); |
| if (!LocationIdx) |
| return Flags; |
| |
| uint32_t Offset = DIE.getOffset() + getULEB128Size(Abbrev->getCode()); |
| const DWARFUnit &OrigUnit = Unit.getOrigUnit(); |
| uint32_t LocationOffset, LocationEndOffset; |
| std::tie(LocationOffset, LocationEndOffset) = |
| getAttributeOffsets(Abbrev, *LocationIdx, Offset, OrigUnit); |
| |
| // See if there is a relocation to a valid debug map entry inside |
| // this variable's location. The order is important here. We want to |
| // always check in the variable has a valid relocation, so that the |
| // DIEInfo is filled. However, we don't want a static variable in a |
| // function to force us to keep the enclosing function. |
| if (!RelocMgr.hasValidRelocation(LocationOffset, LocationEndOffset, MyInfo) || |
| (Flags & TF_InFunctionScope)) |
| return Flags; |
| |
| if (Options.Verbose) { |
| DIDumpOptions DumpOpts; |
| DumpOpts.RecurseDepth = 0; |
| DumpOpts.Verbose = Options.Verbose; |
| DIE.dump(outs(), 8 /* Indent */, DumpOpts); |
| } |
| |
| return Flags | TF_Keep; |
| } |
| |
| /// Check if a function describing DIE should be kept. |
| /// \returns updated TraversalFlags. |
| unsigned DwarfLinker::shouldKeepSubprogramDIE( |
| RelocationManager &RelocMgr, RangesTy &Ranges, const DWARFDie &DIE, |
| const DebugMapObject &DMO, CompileUnit &Unit, CompileUnit::DIEInfo &MyInfo, |
| unsigned Flags) { |
| const auto *Abbrev = DIE.getAbbreviationDeclarationPtr(); |
| |
| Flags |= TF_InFunctionScope; |
| |
| Optional<uint32_t> LowPcIdx = Abbrev->findAttributeIndex(dwarf::DW_AT_low_pc); |
| if (!LowPcIdx) |
| return Flags; |
| |
| uint32_t Offset = DIE.getOffset() + getULEB128Size(Abbrev->getCode()); |
| DWARFUnit &OrigUnit = Unit.getOrigUnit(); |
| uint32_t LowPcOffset, LowPcEndOffset; |
| std::tie(LowPcOffset, LowPcEndOffset) = |
| getAttributeOffsets(Abbrev, *LowPcIdx, Offset, OrigUnit); |
| |
| auto LowPc = dwarf::toAddress(DIE.find(dwarf::DW_AT_low_pc)); |
| assert(LowPc.hasValue() && "low_pc attribute is not an address."); |
| if (!LowPc || |
| !RelocMgr.hasValidRelocation(LowPcOffset, LowPcEndOffset, MyInfo)) |
| return Flags; |
| |
| if (Options.Verbose) { |
| DIDumpOptions DumpOpts; |
| DumpOpts.RecurseDepth = 0; |
| DumpOpts.Verbose = Options.Verbose; |
| DIE.dump(outs(), 8 /* Indent */, DumpOpts); |
| } |
| |
| if (DIE.getTag() == dwarf::DW_TAG_label) { |
| if (Unit.hasLabelAt(*LowPc)) |
| return Flags; |
| // FIXME: dsymutil-classic compat. dsymutil-classic doesn't consider labels |
| // that don't fall into the CU's aranges. This is wrong IMO. Debug info |
| // generation bugs aside, this is really wrong in the case of labels, where |
| // a label marking the end of a function will have a PC == CU's high_pc. |
| if (dwarf::toAddress(OrigUnit.getUnitDIE().find(dwarf::DW_AT_high_pc)) |
| .getValueOr(UINT64_MAX) <= LowPc) |
| return Flags; |
| Unit.addLabelLowPc(*LowPc, MyInfo.AddrAdjust); |
| return Flags | TF_Keep; |
| } |
| |
| Flags |= TF_Keep; |
| |
| Optional<uint64_t> HighPc = DIE.getHighPC(*LowPc); |
| if (!HighPc) { |
| reportWarning("Function without high_pc. Range will be discarded.\n", DMO, |
| &DIE); |
| return Flags; |
| } |
| |
| // Replace the debug map range with a more accurate one. |
| Ranges[*LowPc] = DebugMapObjectRange(*HighPc, MyInfo.AddrAdjust); |
| Unit.addFunctionRange(*LowPc, *HighPc, MyInfo.AddrAdjust); |
| return Flags; |
| } |
| |
| /// Check if a DIE should be kept. |
| /// \returns updated TraversalFlags. |
| unsigned DwarfLinker::shouldKeepDIE(RelocationManager &RelocMgr, |
| RangesTy &Ranges, const DWARFDie &DIE, |
| const DebugMapObject &DMO, |
| CompileUnit &Unit, |
| CompileUnit::DIEInfo &MyInfo, |
| unsigned Flags) { |
| switch (DIE.getTag()) { |
| case dwarf::DW_TAG_constant: |
| case dwarf::DW_TAG_variable: |
| return shouldKeepVariableDIE(RelocMgr, DIE, Unit, MyInfo, Flags); |
| case dwarf::DW_TAG_subprogram: |
| case dwarf::DW_TAG_label: |
| return shouldKeepSubprogramDIE(RelocMgr, Ranges, DIE, DMO, Unit, MyInfo, |
| Flags); |
| case dwarf::DW_TAG_base_type: |
| // DWARF Expressions may reference basic types, but scanning them |
| // is expensive. Basic types are tiny, so just keep all of them. |
| case dwarf::DW_TAG_imported_module: |
| case dwarf::DW_TAG_imported_declaration: |
| case dwarf::DW_TAG_imported_unit: |
| // We always want to keep these. |
| return Flags | TF_Keep; |
| default: |
| break; |
| } |
| |
| return Flags; |
| } |
| |
| /// Mark the passed DIE as well as all the ones it depends on |
| /// as kept. |
| /// |
| /// This function is called by lookForDIEsToKeep on DIEs that are |
| /// newly discovered to be needed in the link. It recursively calls |
| /// back to lookForDIEsToKeep while adding TF_DependencyWalk to the |
| /// TraversalFlags to inform it that it's not doing the primary DIE |
| /// tree walk. |
| void DwarfLinker::keepDIEAndDependencies( |
| RelocationManager &RelocMgr, RangesTy &Ranges, const UnitListTy &Units, |
| const DWARFDie &Die, CompileUnit::DIEInfo &MyInfo, |
| const DebugMapObject &DMO, CompileUnit &CU, bool UseODR) { |
| DWARFUnit &Unit = CU.getOrigUnit(); |
| MyInfo.Keep = true; |
| |
| // We're looking for incomplete types. |
| MyInfo.Incomplete = Die.getTag() != dwarf::DW_TAG_subprogram && |
| Die.getTag() != dwarf::DW_TAG_member && |
| dwarf::toUnsigned(Die.find(dwarf::DW_AT_declaration), 0); |
| |
| // First mark all the parent chain as kept. |
| unsigned AncestorIdx = MyInfo.ParentIdx; |
| while (!CU.getInfo(AncestorIdx).Keep) { |
| unsigned ODRFlag = UseODR ? TF_ODR : 0; |
| lookForDIEsToKeep(RelocMgr, Ranges, Units, Unit.getDIEAtIndex(AncestorIdx), |
| DMO, CU, |
| TF_ParentWalk | TF_Keep | TF_DependencyWalk | ODRFlag); |
| AncestorIdx = CU.getInfo(AncestorIdx).ParentIdx; |
| } |
| |
| // Then we need to mark all the DIEs referenced by this DIE's |
| // attributes as kept. |
| DWARFDataExtractor Data = Unit.getDebugInfoExtractor(); |
| const auto *Abbrev = Die.getAbbreviationDeclarationPtr(); |
| uint32_t Offset = Die.getOffset() + getULEB128Size(Abbrev->getCode()); |
| |
| // Mark all DIEs referenced through attributes as kept. |
| for (const auto &AttrSpec : Abbrev->attributes()) { |
| DWARFFormValue Val(AttrSpec.Form); |
| if (!Val.isFormClass(DWARFFormValue::FC_Reference) || |
| AttrSpec.Attr == dwarf::DW_AT_sibling) { |
| DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset, |
| Unit.getFormParams()); |
| continue; |
| } |
| |
| Val.extractValue(Data, &Offset, Unit.getFormParams(), &Unit); |
| CompileUnit *ReferencedCU; |
| if (auto RefDie = |
| resolveDIEReference(*this, DMO, Units, Val, Die, ReferencedCU)) { |
| uint32_t RefIdx = ReferencedCU->getOrigUnit().getDIEIndex(RefDie); |
| CompileUnit::DIEInfo &Info = ReferencedCU->getInfo(RefIdx); |
| bool IsModuleRef = Info.Ctxt && Info.Ctxt->getCanonicalDIEOffset() && |
| Info.Ctxt->isDefinedInClangModule(); |
| // If the referenced DIE has a DeclContext that has already been |
| // emitted, then do not keep the one in this CU. We'll link to |
| // the canonical DIE in cloneDieReferenceAttribute. |
| // FIXME: compatibility with dsymutil-classic. UseODR shouldn't |
| // be necessary and could be advantageously replaced by |
| // ReferencedCU->hasODR() && CU.hasODR(). |
| // FIXME: compatibility with dsymutil-classic. There is no |
| // reason not to unique ref_addr references. |
| if (AttrSpec.Form != dwarf::DW_FORM_ref_addr && (UseODR || IsModuleRef) && |
| Info.Ctxt && |
| Info.Ctxt != ReferencedCU->getInfo(Info.ParentIdx).Ctxt && |
| Info.Ctxt->getCanonicalDIEOffset() && isODRAttribute(AttrSpec.Attr)) |
| continue; |
| |
| // Keep a module forward declaration if there is no definition. |
| if (!(isODRAttribute(AttrSpec.Attr) && Info.Ctxt && |
| Info.Ctxt->getCanonicalDIEOffset())) |
| Info.Prune = false; |
| |
| unsigned ODRFlag = UseODR ? TF_ODR : 0; |
| lookForDIEsToKeep(RelocMgr, Ranges, Units, RefDie, DMO, *ReferencedCU, |
| TF_Keep | TF_DependencyWalk | ODRFlag); |
| |
| // The incomplete property is propagated if the current DIE is complete |
| // but references an incomplete DIE. |
| if (Info.Incomplete && !MyInfo.Incomplete && |
| (Die.getTag() == dwarf::DW_TAG_typedef || |
| Die.getTag() == dwarf::DW_TAG_member || |
| Die.getTag() == dwarf::DW_TAG_reference_type || |
| Die.getTag() == dwarf::DW_TAG_ptr_to_member_type || |
| Die.getTag() == dwarf::DW_TAG_pointer_type)) |
| MyInfo.Incomplete = true; |
| } |
| } |
| } |
| |
| namespace { |
| /// This class represents an item in the work list. In addition to it's obvious |
| /// purpose of representing the state associated with a particular run of the |
| /// work loop, it also serves as a marker to indicate that we should run the |
| /// "continuation" code. |
| /// |
| /// Originally, the latter was lambda which allowed arbitrary code to be run. |
| /// Because we always need to run the exact same code, it made more sense to |
| /// use a boolean and repurpose the already existing DIE field. |
| struct WorklistItem { |
| DWARFDie Die; |
| unsigned Flags; |
| bool IsContinuation; |
| CompileUnit::DIEInfo *ChildInfo = nullptr; |
| |
| /// Construct a classic worklist item. |
| WorklistItem(DWARFDie Die, unsigned Flags) |
| : Die(Die), Flags(Flags), IsContinuation(false){}; |
| |
| /// Creates a continuation marker. |
| WorklistItem(DWARFDie Die) : Die(Die), IsContinuation(true){}; |
| }; |
| } // namespace |
| |
| // Helper that updates the completeness of the current DIE. It depends on the |
| // fact that the incompletness of its children is already computed. |
| static void updateIncompleteness(const DWARFDie &Die, |
| CompileUnit::DIEInfo &ChildInfo, |
| CompileUnit &CU) { |
| // Only propagate incomplete members. |
| if (Die.getTag() != dwarf::DW_TAG_structure_type && |
| Die.getTag() != dwarf::DW_TAG_class_type) |
| return; |
| |
| unsigned Idx = CU.getOrigUnit().getDIEIndex(Die); |
| CompileUnit::DIEInfo &MyInfo = CU.getInfo(Idx); |
| |
| if (MyInfo.Incomplete) |
| return; |
| |
| if (ChildInfo.Incomplete || ChildInfo.Prune) |
| MyInfo.Incomplete = true; |
| } |
| |
| /// Recursively walk the \p DIE tree and look for DIEs to |
| /// keep. Store that information in \p CU's DIEInfo. |
| /// |
| /// This function is the entry point of the DIE selection |
| /// algorithm. It is expected to walk the DIE tree in file order and |
| /// (though the mediation of its helper) call hasValidRelocation() on |
| /// each DIE that might be a 'root DIE' (See DwarfLinker class |
| /// comment). |
| /// While walking the dependencies of root DIEs, this function is |
| /// also called, but during these dependency walks the file order is |
| /// not respected. The TF_DependencyWalk flag tells us which kind of |
| /// traversal we are currently doing. |
| /// |
| /// The return value indicates whether the DIE is incomplete. |
| void DwarfLinker::lookForDIEsToKeep(RelocationManager &RelocMgr, |
| RangesTy &Ranges, const UnitListTy &Units, |
| const DWARFDie &Die, |
| const DebugMapObject &DMO, CompileUnit &CU, |
| unsigned Flags) { |
| // LIFO work list. |
| SmallVector<WorklistItem, 4> Worklist; |
| Worklist.emplace_back(Die, Flags); |
| |
| while (!Worklist.empty()) { |
| WorklistItem Current = Worklist.back(); |
| Worklist.pop_back(); |
| |
| if (Current.IsContinuation) { |
| updateIncompleteness(Current.Die, *Current.ChildInfo, CU); |
| continue; |
| } |
| |
| unsigned Idx = CU.getOrigUnit().getDIEIndex(Current.Die); |
| CompileUnit::DIEInfo &MyInfo = CU.getInfo(Idx); |
| |
| // At this point we are guaranteed to have a continuation marker before us |
| // in the worklist, except for the last DIE. |
| if (!Worklist.empty()) |
| Worklist.back().ChildInfo = &MyInfo; |
| |
| if (MyInfo.Prune) |
| continue; |
| |
| // If the Keep flag is set, we are marking a required DIE's dependencies. |
| // If our target is already marked as kept, we're all set. |
| bool AlreadyKept = MyInfo.Keep; |
| if ((Current.Flags & TF_DependencyWalk) && AlreadyKept) |
| continue; |
| |
| // We must not call shouldKeepDIE while called from keepDIEAndDependencies, |
| // because it would screw up the relocation finding logic. |
| if (!(Current.Flags & TF_DependencyWalk)) |
| Current.Flags = shouldKeepDIE(RelocMgr, Ranges, Current.Die, DMO, CU, |
| MyInfo, Current.Flags); |
| |
| // If it is a newly kept DIE mark it as well as all its dependencies as |
| // kept. |
| if (!AlreadyKept && (Current.Flags & TF_Keep)) { |
| bool UseOdr = (Current.Flags & TF_DependencyWalk) |
| ? (Current.Flags & TF_ODR) |
| : CU.hasODR(); |
| keepDIEAndDependencies(RelocMgr, Ranges, Units, Current.Die, MyInfo, DMO, |
| CU, UseOdr); |
| } |
| |
| // The TF_ParentWalk flag tells us that we are currently walking up |
| // the parent chain of a required DIE, and we don't want to mark all |
| // the children of the parents as kept (consider for example a |
| // DW_TAG_namespace node in the parent chain). There are however a |
| // set of DIE types for which we want to ignore that directive and still |
| // walk their children. |
| if (dieNeedsChildrenToBeMeaningful(Current.Die.getTag())) |
| Current.Flags &= ~TF_ParentWalk; |
| |
| if (!Current.Die.hasChildren() || (Current.Flags & TF_ParentWalk)) |
| continue; |
| |
| // Add children in reverse order to the worklist to effectively process |
| // them in order. |
| for (auto Child : reverse(Current.Die.children())) { |
| // Add continuation marker before every child to calculate incompleteness |
| // after the last child is processed. We can't store this information in |
| // the same item because we might have to process other continuations |
| // first. |
| Worklist.emplace_back(Current.Die); |
| Worklist.emplace_back(Child, Current.Flags); |
| } |
| } |
| } |
| |
| /// Assign an abbreviation number to \p Abbrev. |
| /// |
| /// Our DIEs get freed after every DebugMapObject has been processed, |
| /// thus the FoldingSet we use to unique DIEAbbrevs cannot refer to |
| /// the instances hold by the DIEs. When we encounter an abbreviation |
| /// that we don't know, we create a permanent copy of it. |
| void DwarfLinker::AssignAbbrev(DIEAbbrev &Abbrev) { |
| // Check the set for priors. |
| FoldingSetNodeID ID; |
| Abbrev.Profile(ID); |
| void *InsertToken; |
| DIEAbbrev *InSet = AbbreviationsSet.FindNodeOrInsertPos(ID, InsertToken); |
| |
| // If it's newly added. |
| if (InSet) { |
| // Assign existing abbreviation number. |
| Abbrev.setNumber(InSet->getNumber()); |
| } else { |
| // Add to abbreviation list. |
| Abbreviations.push_back( |
| llvm::make_unique<DIEAbbrev>(Abbrev.getTag(), Abbrev.hasChildren())); |
| for (const auto &Attr : Abbrev.getData()) |
| Abbreviations.back()->AddAttribute(Attr.getAttribute(), Attr.getForm()); |
| AbbreviationsSet.InsertNode(Abbreviations.back().get(), InsertToken); |
| // Assign the unique abbreviation number. |
| Abbrev.setNumber(Abbreviations.size()); |
| Abbreviations.back()->setNumber(Abbreviations.size()); |
| } |
| } |
| |
| unsigned DwarfLinker::DIECloner::cloneStringAttribute( |
| DIE &Die, AttributeSpec AttrSpec, const DWARFFormValue &Val, |
| const DWARFUnit &U, OffsetsStringPool &StringPool, AttributesInfo &Info) { |
| // Switch everything to out of line strings. |
| const char *String = *Val.getAsCString(); |
| auto StringEntry = StringPool.getEntry(String); |
| |
| // Update attributes info. |
| if (AttrSpec.Attr == dwarf::DW_AT_name) |
| Info.Name = StringEntry; |
| else if (AttrSpec.Attr == dwarf::DW_AT_MIPS_linkage_name || |
| AttrSpec.Attr == dwarf::DW_AT_linkage_name) |
| Info.MangledName = StringEntry; |
| |
| Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), dwarf::DW_FORM_strp, |
| DIEInteger(StringEntry.getOffset())); |
| |
| return 4; |
| } |
| |
| unsigned DwarfLinker::DIECloner::cloneDieReferenceAttribute( |
| DIE &Die, const DWARFDie &InputDIE, AttributeSpec AttrSpec, |
| unsigned AttrSize, const DWARFFormValue &Val, const DebugMapObject &DMO, |
| CompileUnit &Unit) { |
| const DWARFUnit &U = Unit.getOrigUnit(); |
| uint32_t Ref = *Val.getAsReference(); |
| DIE *NewRefDie = nullptr; |
| CompileUnit *RefUnit = nullptr; |
| DeclContext *Ctxt = nullptr; |
| |
| DWARFDie RefDie = |
| resolveDIEReference(Linker, DMO, CompileUnits, Val, InputDIE, RefUnit); |
| |
| // If the referenced DIE is not found, drop the attribute. |
| if (!RefDie || AttrSpec.Attr == dwarf::DW_AT_sibling) |
| return 0; |
| |
| unsigned Idx = RefUnit->getOrigUnit().getDIEIndex(RefDie); |
| CompileUnit::DIEInfo &RefInfo = RefUnit->getInfo(Idx); |
| |
| // If we already have emitted an equivalent DeclContext, just point |
| // at it. |
| if (isODRAttribute(AttrSpec.Attr)) { |
| Ctxt = RefInfo.Ctxt; |
| if (Ctxt && Ctxt->getCanonicalDIEOffset()) { |
| DIEInteger Attr(Ctxt->getCanonicalDIEOffset()); |
| Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), |
| dwarf::DW_FORM_ref_addr, Attr); |
| return U.getRefAddrByteSize(); |
| } |
| } |
| |
| if (!RefInfo.Clone) { |
| assert(Ref > InputDIE.getOffset()); |
| // We haven't cloned this DIE yet. Just create an empty one and |
| // store it. It'll get really cloned when we process it. |
| RefInfo.Clone = DIE::get(DIEAlloc, dwarf::Tag(RefDie.getTag())); |
| } |
| NewRefDie = RefInfo.Clone; |
| |
| if (AttrSpec.Form == dwarf::DW_FORM_ref_addr || |
| (Unit.hasODR() && isODRAttribute(AttrSpec.Attr))) { |
| // We cannot currently rely on a DIEEntry to emit ref_addr |
| // references, because the implementation calls back to DwarfDebug |
| // to find the unit offset. (We don't have a DwarfDebug) |
| // FIXME: we should be able to design DIEEntry reliance on |
| // DwarfDebug away. |
| uint64_t Attr; |
| if (Ref < InputDIE.getOffset()) { |
| // We must have already cloned that DIE. |
| uint32_t NewRefOffset = |
| RefUnit->getStartOffset() + NewRefDie->getOffset(); |
| Attr = NewRefOffset; |
| Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), |
| dwarf::DW_FORM_ref_addr, DIEInteger(Attr)); |
| } else { |
| // A forward reference. Note and fixup later. |
| Attr = 0xBADDEF; |
| Unit.noteForwardReference( |
| NewRefDie, RefUnit, Ctxt, |
| Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), |
| dwarf::DW_FORM_ref_addr, DIEInteger(Attr))); |
| } |
| return U.getRefAddrByteSize(); |
| } |
| |
| Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), |
| dwarf::Form(AttrSpec.Form), DIEEntry(*NewRefDie)); |
| return AttrSize; |
| } |
| |
| void DwarfLinker::DIECloner::cloneExpression( |
| DataExtractor &Data, DWARFExpression Expression, const DebugMapObject &DMO, |
| CompileUnit &Unit, SmallVectorImpl<uint8_t> &OutputBuffer) { |
| using Encoding = DWARFExpression::Operation::Encoding; |
| |
| uint32_t OpOffset = 0; |
| for (auto &Op : Expression) { |
| auto Description = Op.getDescription(); |
| // DW_OP_const_type is variable-length and has 3 |
| // operands. DWARFExpression thus far only supports 2. |
| auto Op0 = Description.Op[0]; |
| auto Op1 = Description.Op[1]; |
| if ((Op0 == Encoding::BaseTypeRef && Op1 != Encoding::SizeNA) || |
| (Op1 == Encoding::BaseTypeRef && Op0 != Encoding::Size1)) |
| Linker.reportWarning("Unsupported DW_OP encoding.", DMO); |
| |
| if ((Op0 == Encoding::BaseTypeRef && Op1 == Encoding::SizeNA) || |
| (Op1 == Encoding::BaseTypeRef && Op0 == Encoding::Size1)) { |
| // This code assumes that the other non-typeref operand fits into 1 byte. |
| assert(OpOffset < Op.getEndOffset()); |
| uint32_t ULEBsize = Op.getEndOffset() - OpOffset - 1; |
| assert(ULEBsize <= 16); |
| |
| // Copy over the operation. |
| OutputBuffer.push_back(Op.getCode()); |
| uint64_t RefOffset; |
| if (Op1 == Encoding::SizeNA) { |
| RefOffset = Op.getRawOperand(0); |
| } else { |
| OutputBuffer.push_back(Op.getRawOperand(0)); |
| RefOffset = Op.getRawOperand(1); |
| } |
| auto RefDie = Unit.getOrigUnit().getDIEForOffset(RefOffset); |
| uint32_t RefIdx = Unit.getOrigUnit().getDIEIndex(RefDie); |
| CompileUnit::DIEInfo &Info = Unit.getInfo(RefIdx); |
| uint32_t Offset = 0; |
| if (DIE *Clone = Info.Clone) |
| Offset = Clone->getOffset(); |
| else |
| Linker.reportWarning("base type ref doesn't point to DW_TAG_base_type.", |
| DMO); |
| uint8_t ULEB[16]; |
| unsigned RealSize = encodeULEB128(Offset, ULEB, ULEBsize); |
| if (RealSize > ULEBsize) { |
| // Emit the generic type as a fallback. |
| RealSize = encodeULEB128(0, ULEB, ULEBsize); |
| Linker.reportWarning("base type ref doesn't fit.", DMO); |
| } |
| assert(RealSize == ULEBsize && "padding failed"); |
| ArrayRef<uint8_t> ULEBbytes(ULEB, ULEBsize); |
| OutputBuffer.append(ULEBbytes.begin(), ULEBbytes.end()); |
| } else { |
| // Copy over everything else unmodified. |
| StringRef Bytes = Data.getData().slice(OpOffset, Op.getEndOffset()); |
| OutputBuffer.append(Bytes.begin(), Bytes.end()); |
| } |
| OpOffset = Op.getEndOffset(); |
| } |
| } |
| |
| unsigned DwarfLinker::DIECloner::cloneBlockAttribute( |
| DIE &Die, const DebugMapObject &DMO, CompileUnit &Unit, |
| AttributeSpec AttrSpec, const DWARFFormValue &Val, unsigned AttrSize, |
| bool IsLittleEndian) { |
| DIEValueList *Attr; |
| DIEValue Value; |
| DIELoc *Loc = nullptr; |
| DIEBlock *Block = nullptr; |
| if (AttrSpec.Form == dwarf::DW_FORM_exprloc) { |
| Loc = new (DIEAlloc) DIELoc; |
| Linker.DIELocs.push_back(Loc); |
| } else { |
| Block = new (DIEAlloc) DIEBlock; |
| Linker.DIEBlocks.push_back(Block); |
| } |
| Attr = Loc ? static_cast<DIEValueList *>(Loc) |
| : static_cast<DIEValueList *>(Block); |
| |
| if (Loc) |
| Value = DIEValue(dwarf::Attribute(AttrSpec.Attr), |
| dwarf::Form(AttrSpec.Form), Loc); |
| else |
| Value = DIEValue(dwarf::Attribute(AttrSpec.Attr), |
| dwarf::Form(AttrSpec.Form), Block); |
| |
| // If the block is a DWARF Expression, clone it into the temporary |
| // buffer using cloneExpression(), otherwise copy the data directly. |
| SmallVector<uint8_t, 32> Buffer; |
| ArrayRef<uint8_t> Bytes = *Val.getAsBlock(); |
| if (DWARFAttribute::mayHaveLocationDescription(AttrSpec.Attr) && |
| (Val.isFormClass(DWARFFormValue::FC_Block) || |
| Val.isFormClass(DWARFFormValue::FC_Exprloc))) { |
| DWARFUnit &OrigUnit = Unit.getOrigUnit(); |
| DataExtractor Data(StringRef((const char *)Bytes.data(), Bytes.size()), |
| IsLittleEndian, OrigUnit.getAddressByteSize()); |
| DWARFExpression Expr(Data, OrigUnit.getVersion(), |
| OrigUnit.getAddressByteSize()); |
| cloneExpression(Data, Expr, DMO, Unit, Buffer); |
| Bytes = Buffer; |
| } |
| for (auto Byte : Bytes) |
| Attr->addValue(DIEAlloc, static_cast<dwarf::Attribute>(0), |
| dwarf::DW_FORM_data1, DIEInteger(Byte)); |
| |
| // FIXME: If DIEBlock and DIELoc just reuses the Size field of |
| // the DIE class, this if could be replaced by |
| // Attr->setSize(Bytes.size()). |
| if (Linker.Streamer) { |
| auto *AsmPrinter = &Linker.Streamer->getAsmPrinter(); |
| if (Loc) |
| Loc->ComputeSize(AsmPrinter); |
| else |
| Block->ComputeSize(AsmPrinter); |
| } |
| Die.addValue(DIEAlloc, Value); |
| return AttrSize; |
| } |
| |
| unsigned DwarfLinker::DIECloner::cloneAddressAttribute( |
| DIE &Die, AttributeSpec AttrSpec, const DWARFFormValue &Val, |
| const CompileUnit &Unit, AttributesInfo &Info) { |
| uint64_t Addr = *Val.getAsAddress(); |
| |
| if (LLVM_UNLIKELY(Linker.Options.Update)) { |
| if (AttrSpec.Attr == dwarf::DW_AT_low_pc) |
| Info.HasLowPc = true; |
| Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), |
| dwarf::Form(AttrSpec.Form), DIEInteger(Addr)); |
| return Unit.getOrigUnit().getAddressByteSize(); |
| } |
| |
| if (AttrSpec.Attr == dwarf::DW_AT_low_pc) { |
| if (Die.getTag() == dwarf::DW_TAG_inlined_subroutine || |
| Die.getTag() == dwarf::DW_TAG_lexical_block) |
| // The low_pc of a block or inline subroutine might get |
| // relocated because it happens to match the low_pc of the |
| // enclosing subprogram. To prevent issues with that, always use |
| // the low_pc from the input DIE if relocations have been applied. |
| Addr = (Info.OrigLowPc != std::numeric_limits<uint64_t>::max() |
| ? Info.OrigLowPc |
| : Addr) + |
| Info.PCOffset; |
| else if (Die.getTag() == dwarf::DW_TAG_compile_unit) { |
| Addr = Unit.getLowPc(); |
| if (Addr == std::numeric_limits<uint64_t>::max()) |
| return 0; |
| } |
| Info.HasLowPc = true; |
| } else if (AttrSpec.Attr == dwarf::DW_AT_high_pc) { |
| if (Die.getTag() == dwarf::DW_TAG_compile_unit) { |
| if (uint64_t HighPc = Unit.getHighPc()) |
| Addr = HighPc; |
| else |
| return 0; |
| } else |
| // If we have a high_pc recorded for the input DIE, use |
| // it. Otherwise (when no relocations where applied) just use the |
| // one we just decoded. |
| Addr = (Info.OrigHighPc ? Info.OrigHighPc : Addr) + Info.PCOffset; |
| } |
| |
| Die.addValue(DIEAlloc, static_cast<dwarf::Attribute>(AttrSpec.Attr), |
| static_cast<dwarf::Form>(AttrSpec.Form), DIEInteger(Addr)); |
| return Unit.getOrigUnit().getAddressByteSize(); |
| } |
| |
| unsigned DwarfLinker::DIECloner::cloneScalarAttribute( |
| DIE &Die, const DWARFDie &InputDIE, const DebugMapObject &DMO, |
| CompileUnit &Unit, AttributeSpec AttrSpec, const DWARFFormValue &Val, |
| unsigned AttrSize, AttributesInfo &Info) { |
| uint64_t Value; |
| |
| if (LLVM_UNLIKELY(Linker.Options.Update)) { |
| if (auto OptionalValue = Val.getAsUnsignedConstant()) |
| Value = *OptionalValue; |
| else if (auto OptionalValue = Val.getAsSignedConstant()) |
| Value = *OptionalValue; |
| else if (auto OptionalValue = Val.getAsSectionOffset()) |
| Value = *OptionalValue; |
| else { |
| Linker.reportWarning( |
| "Unsupported scalar attribute form. Dropping attribute.", DMO, |
| &InputDIE); |
| return 0; |
| } |
| if (AttrSpec.Attr == dwarf::DW_AT_declaration && Value) |
| Info.IsDeclaration = true; |
| Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), |
| dwarf::Form(AttrSpec.Form), DIEInteger(Value)); |
| return AttrSize; |
| } |
| |
| if (AttrSpec.Attr == dwarf::DW_AT_high_pc && |
| Die.getTag() == dwarf::DW_TAG_compile_unit) { |
| if (Unit.getLowPc() == -1ULL) |
| return 0; |
| // Dwarf >= 4 high_pc is an size, not an address. |
| Value = Unit.getHighPc() - Unit.getLowPc(); |
| } else if (AttrSpec.Form == dwarf::DW_FORM_sec_offset) |
| Value = *Val.getAsSectionOffset(); |
| else if (AttrSpec.Form == dwarf::DW_FORM_sdata) |
| Value = *Val.getAsSignedConstant(); |
| else if (auto OptionalValue = Val.getAsUnsignedConstant()) |
| Value = *OptionalValue; |
| else { |
| Linker.reportWarning( |
| "Unsupported scalar attribute form. Dropping attribute.", DMO, |
| &InputDIE); |
| return 0; |
| } |
| PatchLocation Patch = |
| Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), |
| dwarf::Form(AttrSpec.Form), DIEInteger(Value)); |
| if (AttrSpec.Attr == dwarf::DW_AT_ranges) { |
| Unit.noteRangeAttribute(Die, Patch); |
| Info.HasRanges = true; |
| } |
| |
| // A more generic way to check for location attributes would be |
| // nice, but it's very unlikely that any other attribute needs a |
| // location list. |
| // FIXME: use DWARFAttribute::mayHaveLocationDescription(). |
| else if (AttrSpec.Attr == dwarf::DW_AT_location || |
| AttrSpec.Attr == dwarf::DW_AT_frame_base) |
| Unit.noteLocationAttribute(Patch, Info.PCOffset); |
| else if (AttrSpec.Attr == dwarf::DW_AT_declaration && Value) |
| Info.IsDeclaration = true; |
| |
| return AttrSize; |
| } |
| |
| /// Clone \p InputDIE's attribute described by \p AttrSpec with |
| /// value \p Val, and add it to \p Die. |
| /// \returns the size of the cloned attribute. |
| unsigned DwarfLinker::DIECloner::cloneAttribute( |
| DIE &Die, const DWARFDie &InputDIE, const DebugMapObject &DMO, |
| CompileUnit &Unit, OffsetsStringPool &StringPool, const DWARFFormValue &Val, |
| const AttributeSpec AttrSpec, unsigned AttrSize, AttributesInfo &Info, |
| bool IsLittleEndian) { |
| const DWARFUnit &U = Unit.getOrigUnit(); |
| |
| switch (AttrSpec.Form) { |
| case dwarf::DW_FORM_strp: |
| case dwarf::DW_FORM_string: |
| return cloneStringAttribute(Die, AttrSpec, Val, U, StringPool, Info); |
| case dwarf::DW_FORM_ref_addr: |
| case dwarf::DW_FORM_ref1: |
| case dwarf::DW_FORM_ref2: |
| case dwarf::DW_FORM_ref4: |
| case dwarf::DW_FORM_ref8: |
| return cloneDieReferenceAttribute(Die, InputDIE, AttrSpec, AttrSize, Val, |
| DMO, Unit); |
| case dwarf::DW_FORM_block: |
| case dwarf::DW_FORM_block1: |
| case dwarf::DW_FORM_block2: |
| case dwarf::DW_FORM_block4: |
| case dwarf::DW_FORM_exprloc: |
| return cloneBlockAttribute(Die, DMO, Unit, AttrSpec, Val, AttrSize, |
| IsLittleEndian); |
| case dwarf::DW_FORM_addr: |
| return cloneAddressAttribute(Die, AttrSpec, Val, Unit, Info); |
| case dwarf::DW_FORM_data1: |
| case dwarf::DW_FORM_data2: |
| case dwarf::DW_FORM_data4: |
| case dwarf::DW_FORM_data8: |
| case dwarf::DW_FORM_udata: |
| case dwarf::DW_FORM_sdata: |
| case dwarf::DW_FORM_sec_offset: |
| case dwarf::DW_FORM_flag: |
| case dwarf::DW_FORM_flag_present: |
| return cloneScalarAttribute(Die, InputDIE, DMO, Unit, AttrSpec, Val, |
| AttrSize, Info); |
| default: |
| Linker.reportWarning( |
| "Unsupported attribute form in cloneAttribute. Dropping.", DMO, |
| &InputDIE); |
| } |
| |
| return 0; |
| } |
| |
| /// Apply the valid relocations found by findValidRelocs() to |
| /// the buffer \p Data, taking into account that Data is at \p BaseOffset |
| /// in the debug_info section. |
| /// |
| /// Like for findValidRelocs(), this function must be called with |
| /// monotonic \p BaseOffset values. |
| /// |
| /// \returns whether any reloc has been applied. |
| bool DwarfLinker::RelocationManager::applyValidRelocs( |
| MutableArrayRef<char> Data, uint32_t BaseOffset, bool IsLittleEndian) { |
| assert((NextValidReloc == 0 || |
| BaseOffset > ValidRelocs[NextValidReloc - 1].Offset) && |
| "BaseOffset should only be increasing."); |
| if (NextValidReloc >= ValidRelocs.size()) |
| return false; |
| |
| // Skip relocs that haven't been applied. |
| while (NextValidReloc < ValidRelocs.size() && |
| ValidRelocs[NextValidReloc].Offset < BaseOffset) |
| ++NextValidReloc; |
| |
| bool Applied = false; |
| uint64_t EndOffset = BaseOffset + Data.size(); |
| while (NextValidReloc < ValidRelocs.size() && |
| ValidRelocs[NextValidReloc].Offset >= BaseOffset && |
| ValidRelocs[NextValidReloc].Offset < EndOffset) { |
| const auto &ValidReloc = ValidRelocs[NextValidReloc++]; |
| assert(ValidReloc.Offset - BaseOffset < Data.size()); |
| assert(ValidReloc.Offset - BaseOffset + ValidReloc.Size <= Data.size()); |
| char Buf[8]; |
| uint64_t Value = ValidReloc.Mapping->getValue().BinaryAddress; |
| Value += ValidReloc.Addend; |
| for (unsigned i = 0; i != ValidReloc.Size; ++i) { |
| unsigned Index = IsLittleEndian ? i : (ValidReloc.Size - i - 1); |
| Buf[i] = uint8_t(Value >> (Index * 8)); |
| } |
| assert(ValidReloc.Size <= sizeof(Buf)); |
| memcpy(&Data[ValidReloc.Offset - BaseOffset], Buf, ValidReloc.Size); |
| Applied = true; |
| } |
| |
| return Applied; |
| } |
| |
| static bool isObjCSelector(StringRef Name) { |
| return Name.size() > 2 && (Name[0] == '-' || Name[0] == '+') && |
| (Name[1] == '['); |
| } |
| |
| void DwarfLinker::DIECloner::addObjCAccelerator(CompileUnit &Unit, |
| const DIE *Die, |
| DwarfStringPoolEntryRef Name, |
| OffsetsStringPool &StringPool, |
| bool SkipPubSection) { |
| assert(isObjCSelector(Name.getString()) && "not an objc selector"); |
| // Objective C method or class function. |
| // "- [Class(Category) selector :withArg ...]" |
| StringRef ClassNameStart(Name.getString().drop_front(2)); |
| size_t FirstSpace = ClassNameStart.find(' '); |
| if (FirstSpace == StringRef::npos) |
| return; |
| |
| StringRef SelectorStart(ClassNameStart.data() + FirstSpace + 1); |
| if (!SelectorStart.size()) |
| return; |
| |
| StringRef Selector(SelectorStart.data(), SelectorStart.size() - 1); |
| Unit.addNameAccelerator(Die, StringPool.getEntry(Selector), SkipPubSection); |
| |
| // Add an entry for the class name that points to this |
| // method/class function. |
| StringRef ClassName(ClassNameStart.data(), FirstSpace); |
| Unit.addObjCAccelerator(Die, StringPool.getEntry(ClassName), SkipPubSection); |
| |
| if (ClassName[ClassName.size() - 1] == ')') { |
| size_t OpenParens = ClassName.find('('); |
| if (OpenParens != StringRef::npos) { |
| StringRef ClassNameNoCategory(ClassName.data(), OpenParens); |
| Unit.addObjCAccelerator(Die, StringPool.getEntry(ClassNameNoCategory), |
| SkipPubSection); |
| |
| std::string MethodNameNoCategory(Name.getString().data(), OpenParens + 2); |
| // FIXME: The missing space here may be a bug, but |
| // dsymutil-classic also does it this way. |
| MethodNameNoCategory.append(SelectorStart); |
| Unit.addNameAccelerator(Die, StringPool.getEntry(MethodNameNoCategory), |
| SkipPubSection); |
| } |
| } |
| } |
| |
| static bool |
| shouldSkipAttribute(DWARFAbbreviationDeclaration::AttributeSpec AttrSpec, |
| uint16_t Tag, bool InDebugMap, bool SkipPC, |
| bool InFunctionScope) { |
| switch (AttrSpec.Attr) { |
| default: |
| return false; |
| case dwarf::DW_AT_low_pc: |
| case dwarf::DW_AT_high_pc: |
| case dwarf::DW_AT_ranges: |
| return SkipPC; |
| case dwarf::DW_AT_location: |
| case dwarf::DW_AT_frame_base: |
| // FIXME: for some reason dsymutil-classic keeps the location attributes |
| // when they are of block type (i.e. not location lists). This is totally |
| // wrong for globals where we will keep a wrong address. It is mostly |
| // harmless for locals, but there is no point in keeping these anyway when |
| // the function wasn't linked. |
| return (SkipPC || (!InFunctionScope && Tag == dwarf::DW_TAG_variable && |
| !InDebugMap)) && |
| !DWARFFormValue(AttrSpec.Form).isFormClass(DWARFFormValue::FC_Block); |
| } |
| } |
| |
| DIE *DwarfLinker::DIECloner::cloneDIE( |
| const DWARFDie &InputDIE, const DebugMapObject &DMO, CompileUnit &Unit, |
| OffsetsStringPool &StringPool, int64_t PCOffset, uint32_t OutOffset, |
| unsigned Flags, bool IsLittleEndian, DIE *Die) { |
| DWARFUnit &U = Unit.getOrigUnit(); |
| unsigned Idx = U.getDIEIndex(InputDIE); |
| CompileUnit::DIEInfo &Info = Unit.getInfo(Idx); |
| |
| // Should the DIE appear in the output? |
| if (!Unit.getInfo(Idx).Keep) |
| return nullptr; |
| |
| uint32_t Offset = InputDIE.getOffset(); |
| assert(!(Die && Info.Clone) && "Can't supply a DIE and a cloned DIE"); |
| if (!Die) { |
| // The DIE might have been already created by a forward reference |
| // (see cloneDieReferenceAttribute()). |
| if (!Info.Clone) |
| Info.Clone = DIE::get(DIEAlloc, dwarf::Tag(InputDIE.getTag())); |
| Die = Info.Clone; |
| } |
| |
| assert(Die->getTag() == InputDIE.getTag()); |
| Die->setOffset(OutOffset); |
| if ((Unit.hasODR() || Unit.isClangModule()) && !Info.Incomplete && |
| Die->getTag() != dwarf::DW_TAG_namespace && Info.Ctxt && |
| Info.Ctxt != Unit.getInfo(Info.ParentIdx).Ctxt && |
| !Info.Ctxt->getCanonicalDIEOffset()) { |
| // We are about to emit a DIE that is the root of its own valid |
| // DeclContext tree. Make the current offset the canonical offset |
| // for this context. |
| Info.Ctxt->setCanonicalDIEOffset(OutOffset + Unit.getStartOffset()); |
| } |
| |
| // Extract and clone every attribute. |
| DWARFDataExtractor Data = U.getDebugInfoExtractor(); |
| // Point to the next DIE (generally there is always at least a NULL |
| // entry after the current one). If this is a lone |
| // DW_TAG_compile_unit without any children, point to the next unit. |
| uint32_t NextOffset = (Idx + 1 < U.getNumDIEs()) |
| ? U.getDIEAtIndex(Idx + 1).getOffset() |
| : U.getNextUnitOffset(); |
| AttributesInfo AttrInfo; |
| |
| // We could copy the data only if we need to apply a relocation to it. After |
| // testing, it seems there is no performance downside to doing the copy |
| // unconditionally, and it makes the code simpler. |
| SmallString<40> DIECopy(Data.getData().substr(Offset, NextOffset - Offset)); |
| Data = |
| DWARFDataExtractor(DIECopy, Data.isLittleEndian(), Data.getAddressSize()); |
| // Modify the copy with relocated addresses. |
| if (RelocMgr.applyValidRelocs(DIECopy, Offset, Data.isLittleEndian())) { |
| // If we applied relocations, we store the value of high_pc that was |
| // potentially stored in the input DIE. If high_pc is an address |
| // (Dwarf version == 2), then it might have been relocated to a |
| // totally unrelated value (because the end address in the object |
| // file might be start address of another function which got moved |
| // independently by the linker). The computation of the actual |
| // high_pc value is done in cloneAddressAttribute(). |
| AttrInfo.OrigHighPc = |
| dwarf::toAddress(InputDIE.find(dwarf::DW_AT_high_pc), 0); |
| // Also store the low_pc. It might get relocated in an |
| // inline_subprogram that happens at the beginning of its |
| // inlining function. |
| AttrInfo.OrigLowPc = dwarf::toAddress(InputDIE.find(dwarf::DW_AT_low_pc), |
| std::numeric_limits<uint64_t>::max()); |
| } |
| |
| // Reset the Offset to 0 as we will be working on the local copy of |
| // the data. |
| Offset = 0; |
| |
| const auto *Abbrev = InputDIE.getAbbreviationDeclarationPtr(); |
| Offset += getULEB128Size(Abbrev->getCode()); |
| |
| // We are entering a subprogram. Get and propagate the PCOffset. |
| if (Die->getTag() == dwarf::DW_TAG_subprogram) |
| PCOffset = Info.AddrAdjust; |
| AttrInfo.PCOffset = PCOffset; |
| |
| if (Abbrev->getTag() == dwarf::DW_TAG_subprogram) { |
| Flags |= TF_InFunctionScope; |
| if (!Info.InDebugMap && LLVM_LIKELY(!Options.Update)) |
| Flags |= TF_SkipPC; |
| } |
| |
| bool Copied = false; |
| for (const auto &AttrSpec : Abbrev->attributes()) { |
| if (LLVM_LIKELY(!Options.Update) && |
| shouldSkipAttribute(AttrSpec, Die->getTag(), Info.InDebugMap, |
| Flags & TF_SkipPC, Flags & TF_InFunctionScope)) { |
| DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset, |
| U.getFormParams()); |
| // FIXME: dsymutil-classic keeps the old abbreviation around |
| // even if it's not used. We can remove this (and the copyAbbrev |
| // helper) as soon as bit-for-bit compatibility is not a goal anymore. |
| if (!Copied) { |
| copyAbbrev(*InputDIE.getAbbreviationDeclarationPtr(), Unit.hasODR()); |
| Copied = true; |
| } |
| continue; |
| } |
| |
| DWARFFormValue Val(AttrSpec.Form); |
| uint32_t AttrSize = Offset; |
| Val.extractValue(Data, &Offset, U.getFormParams(), &U); |
| AttrSize = Offset - AttrSize; |
| |
| OutOffset += cloneAttribute(*Die, InputDIE, DMO, Unit, StringPool, Val, |
| AttrSpec, AttrSize, AttrInfo, IsLittleEndian); |
| } |
| |
| // Look for accelerator entries. |
| uint16_t Tag = InputDIE.getTag(); |
| // FIXME: This is slightly wrong. An inline_subroutine without a |
| // low_pc, but with AT_ranges might be interesting to get into the |
| // accelerator tables too. For now stick with dsymutil's behavior. |
| if ((Info.InDebugMap || AttrInfo.HasLowPc || AttrInfo.HasRanges) && |
| Tag != dwarf::DW_TAG_compile_unit && |
| getDIENames(InputDIE, AttrInfo, StringPool, |
| Tag != dwarf::DW_TAG_inlined_subroutine)) { |
| if (AttrInfo.MangledName && AttrInfo.MangledName != AttrInfo.Name) |
| Unit.addNameAccelerator(Die, AttrInfo.MangledName, |
| Tag == dwarf::DW_TAG_inlined_subroutine); |
| if (AttrInfo.Name) { |
| if (AttrInfo.NameWithoutTemplate) |
| Unit.addNameAccelerator(Die, AttrInfo.NameWithoutTemplate, |
| /* SkipPubSection */ true); |
| Unit.addNameAccelerator(Die, AttrInfo.Name, |
| Tag == dwarf::DW_TAG_inlined_subroutine); |
| } |
| if (AttrInfo.Name && isObjCSelector(AttrInfo.Name.getString())) |
| addObjCAccelerator(Unit, Die, AttrInfo.Name, StringPool, |
| /* SkipPubSection =*/true); |
| |
| } else if (Tag == dwarf::DW_TAG_namespace) { |
| if (!AttrInfo.Name) |
| AttrInfo.Name = StringPool.getEntry("(anonymous namespace)"); |
| Unit.addNamespaceAccelerator(Die, AttrInfo.Name); |
| } else if (isTypeTag(Tag) && !AttrInfo.IsDeclaration && |
| getDIENames(InputDIE, AttrInfo, StringPool) && AttrInfo.Name && |
| AttrInfo.Name.getString()[0]) { |
| uint32_t Hash = hashFullyQualifiedName(InputDIE, Unit, DMO); |
| uint64_t RuntimeLang = |
| dwarf::toUnsigned(InputDIE.find(dwarf::DW_AT_APPLE_runtime_class)) |
| .getValueOr(0); |
| bool ObjCClassIsImplementation = |
| (RuntimeLang == dwarf::DW_LANG_ObjC || |
| RuntimeLang == dwarf::DW_LANG_ObjC_plus_plus) && |
| dwarf::toUnsigned(InputDIE.find(dwarf::DW_AT_APPLE_objc_complete_type)) |
| .getValueOr(0); |
| Unit.addTypeAccelerator(Die, AttrInfo.Name, ObjCClassIsImplementation, |
| Hash); |
| } |
| |
| // Determine whether there are any children that we want to keep. |
| bool HasChildren = false; |
| for (auto Child : InputDIE.children()) { |
| unsigned Idx = U.getDIEIndex(Child); |
| if (Unit.getInfo(Idx).Keep) { |
| HasChildren = true; |
| break; |
| } |
| } |
| |
| DIEAbbrev NewAbbrev = Die->generateAbbrev(); |
| if (HasChildren) |
| NewAbbrev.setChildrenFlag(dwarf::DW_CHILDREN_yes); |
| // Assign a permanent abbrev number |
| Linker.AssignAbbrev(NewAbbrev); |
| Die->setAbbrevNumber(NewAbbrev.getNumber()); |
| |
| // Add the size of the abbreviation number to the output offset. |
| OutOffset += getULEB128Size(Die->getAbbrevNumber()); |
| |
| if (!HasChildren) { |
| // Update our size. |
| Die->setSize(OutOffset - Die->getOffset()); |
| return Die; |
| } |
| |
| // Recursively clone children. |
| for (auto Child : InputDIE.children()) { |
| if (DIE *Clone = cloneDIE(Child, DMO, Unit, StringPool, PCOffset, OutOffset, |
| Flags, IsLittleEndian)) { |
| Die->addChild(Clone); |
| OutOffset = Clone->getOffset() + Clone->getSize(); |
| } |
| } |
| |
| // Account for the end of children marker. |
| OutOffset += sizeof(int8_t); |
| // Update our size. |
| Die->setSize(OutOffset - Die->getOffset()); |
| return Die; |
| } |
| |
| /// Patch the input object file relevant debug_ranges entries |
| /// and emit them in the output file. Update the relevant attributes |
| /// to point at the new entries. |
| void DwarfLinker::patchRangesForUnit(const CompileUnit &Unit, |
| DWARFContext &OrigDwarf, |
| const DebugMapObject &DMO) const { |
| DWARFDebugRangeList RangeList; |
| const auto &FunctionRanges = Unit.getFunctionRanges(); |
| unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize(); |
| DWARFDataExtractor RangeExtractor(OrigDwarf.getDWARFObj(), |
| OrigDwarf.getDWARFObj().getRangeSection(), |
| OrigDwarf.isLittleEndian(), AddressSize); |
| auto InvalidRange = FunctionRanges.end(), CurrRange = InvalidRange; |
| DWARFUnit &OrigUnit = Unit.getOrigUnit(); |
| auto OrigUnitDie = OrigUnit.getUnitDIE(false); |
| uint64_t OrigLowPc = |
| dwarf::toAddress(OrigUnitDie.find(dwarf::DW_AT_low_pc), -1ULL); |
| // Ranges addresses are based on the unit's low_pc. Compute the |
| // offset we need to apply to adapt to the new unit's low_pc. |
| int64_t UnitPcOffset = 0; |
| if (OrigLowPc != -1ULL) |
| UnitPcOffset = int64_t(OrigLowPc) - Unit.getLowPc(); |
| |
| for (const auto &RangeAttribute : Unit.getRangesAttributes()) { |
| uint32_t Offset = RangeAttribute.get(); |
| RangeAttribute.set(Streamer->getRangesSectionSize()); |
| if (Error E = RangeList.extract(RangeExtractor, &Offset)) { |
| llvm::consumeError(std::move(E)); |
| reportWarning("invalid range list ignored.", DMO); |
| RangeList.clear(); |
| } |
| const auto &Entries = RangeList.getEntries(); |
| if (!Entries.empty()) { |
| const DWARFDebugRangeList::RangeListEntry &First = Entries.front(); |
| |
| if (CurrRange == InvalidRange || |
| First.StartAddress + OrigLowPc < CurrRange.start() || |
| First.StartAddress + OrigLowPc >= CurrRange.stop()) { |
| CurrRange = FunctionRanges.find(First.StartAddress + OrigLowPc); |
| if (CurrRange == InvalidRange || |
| CurrRange.start() > First.StartAddress + OrigLowPc) { |
| reportWarning("no mapping for range.", DMO); |
| continue; |
| } |
| } |
| } |
| |
| Streamer->emitRangesEntries(UnitPcOffset, OrigLowPc, CurrRange, Entries, |
| AddressSize); |
| } |
| } |
| |
| /// Generate the debug_aranges entries for \p Unit and if the |
| /// unit has a DW_AT_ranges attribute, also emit the debug_ranges |
| /// contribution for this attribute. |
| /// FIXME: this could actually be done right in patchRangesForUnit, |
| /// but for the sake of initial bit-for-bit compatibility with legacy |
| /// dsymutil, we have to do it in a delayed pass. |
| void DwarfLinker::generateUnitRanges(CompileUnit &Unit) const { |
| auto Attr = Unit.getUnitRangesAttribute(); |
| if (Attr) |
| Attr->set(Streamer->getRangesSectionSize()); |
| Streamer->emitUnitRangesEntries(Unit, static_cast<bool>(Attr)); |
| } |
| |
| /// Insert the new line info sequence \p Seq into the current |
| /// set of already linked line info \p Rows. |
| static void insertLineSequence(std::vector<DWARFDebugLine::Row> &Seq, |
| std::vector<DWARFDebugLine::Row> &Rows) { |
| if (Seq.empty()) |
| return; |
| |
| if (!Rows.empty() && Rows.back().Address < Seq.front().Address) { |
| Rows.insert(Rows.end(), Seq.begin(), Seq.end()); |
| Seq.clear(); |
| return; |
| } |
| |
| auto InsertPoint = std::lower_bound( |
| Rows.begin(), Rows.end(), Seq.front(), |
| [](const DWARFDebugLine::Row &LHS, const DWARFDebugLine::Row &RHS) { |
| return LHS.Address < RHS.Address; |
| }); |
| |
| // FIXME: this only removes the unneeded end_sequence if the |
| // sequences have been inserted in order. Using a global sort like |
| // described in patchLineTableForUnit() and delaying the end_sequene |
| // elimination to emitLineTableForUnit() we can get rid of all of them. |
| if (InsertPoint != Rows.end() && |
| InsertPoint->Address == Seq.front().Address && InsertPoint->EndSequence) { |
| *InsertPoint = Seq.front(); |
| Rows.insert(InsertPoint + 1, Seq.begin() + 1, Seq.end()); |
| } else { |
| Rows.insert(InsertPoint, Seq.begin(), Seq.end()); |
| } |
| |
| Seq.clear(); |
| } |
| |
| static void patchStmtList(DIE &Die, DIEInteger Offset) { |
| for (auto &V : Die.values()) |
| if (V.getAttribute() == dwarf::DW_AT_stmt_list) { |
| V = DIEValue(V.getAttribute(), V.getForm(), Offset); |
| return; |
| } |
| |
| llvm_unreachable("Didn't find DW_AT_stmt_list in cloned DIE!"); |
| } |
| |
| /// Extract the line table for \p Unit from \p OrigDwarf, and |
| /// recreate a relocated version of these for the address ranges that |
| /// are present in the binary. |
| void DwarfLinker::patchLineTableForUnit(CompileUnit &Unit, |
| DWARFContext &OrigDwarf, |
| RangesTy &Ranges, |
| const DebugMapObject &DMO) { |
| DWARFDie CUDie = Unit.getOrigUnit().getUnitDIE(); |
| auto StmtList = dwarf::toSectionOffset(CUDie.find(dwarf::DW_AT_stmt_list)); |
| if (!StmtList) |
| return; |
| |
| // Update the cloned DW_AT_stmt_list with the correct debug_line offset. |
| if (auto *OutputDIE = Unit.getOutputUnitDIE()) |
| patchStmtList(*OutputDIE, DIEInteger(Streamer->getLineSectionSize())); |
| |
| // Parse the original line info for the unit. |
| DWARFDebugLine::LineTable LineTable; |
| uint32_t StmtOffset = *StmtList; |
| DWARFDataExtractor LineExtractor( |
| OrigDwarf.getDWARFObj(), OrigDwarf.getDWARFObj().getLineSection(), |
| OrigDwarf.isLittleEndian(), Unit.getOrigUnit().getAddressByteSize()); |
| if (Options.Translator) |
| return Streamer->translateLineTable(LineExtractor, StmtOffset, Options); |
| |
| Error Err = LineTable.parse(LineExtractor, &StmtOffset, OrigDwarf, |
| &Unit.getOrigUnit(), DWARFContext::dumpWarning); |
| DWARFContext::dumpWarning(std::move(Err)); |
| |
| // This vector is the output line table. |
| std::vector<DWARFDebugLine::Row> NewRows; |
| NewRows.reserve(LineTable.Rows.size()); |
| |
| // Current sequence of rows being extracted, before being inserted |
| // in NewRows. |
| std::vector<DWARFDebugLine::Row> Seq; |
| const auto &FunctionRanges = Unit.getFunctionRanges(); |
| auto InvalidRange = FunctionRanges.end(), CurrRange = InvalidRange; |
| |
| // FIXME: This logic is meant to generate exactly the same output as |
| // Darwin's classic dsymutil. There is a nicer way to implement this |
| // by simply putting all the relocated line info in NewRows and simply |
| // sorting NewRows before passing it to emitLineTableForUnit. This |
| // should be correct as sequences for a function should stay |
| // together in the sorted output. There are a few corner cases that |
| // look suspicious though, and that required to implement the logic |
| // this way. Revisit that once initial validation is finished. |
| |
| // Iterate over the object file line info and extract the sequences |
| // that correspond to linked functions. |
| for (auto &Row : LineTable.Rows) { |
| // Check whether we stepped out of the range. The range is |
| // half-open, but consider accept the end address of the range if |
| // it is marked as end_sequence in the input (because in that |
| // case, the relocation offset is accurate and that entry won't |
| // serve as the start of another function). |
| if (CurrRange == InvalidRange || Row.Address.Address < CurrRange.start() || |
| Row.Address.Address > CurrRange.stop() || |
| (Row.Address.Address == CurrRange.stop() && !Row.EndSequence)) { |
| // We just stepped out of a known range. Insert a end_sequence |
| // corresponding to the end of the range. |
| uint64_t StopAddress = CurrRange != InvalidRange |
| ? CurrRange.stop() + CurrRange.value() |
| : -1ULL; |
| CurrRange = FunctionRanges.find(Row.Address.Address); |
| bool CurrRangeValid = |
| CurrRange != InvalidRange && CurrRange.start() <= Row.Address.Address; |
| if (!CurrRangeValid) { |
| CurrRange = InvalidRange; |
| if (StopAddress != -1ULL) { |
| // Try harder by looking in the DebugMapObject function |
| // ranges map. There are corner cases where this finds a |
| // valid entry. It's unclear if this is right or wrong, but |
| // for now do as dsymutil. |
| // FIXME: Understand exactly what cases this addresses and |
| // potentially remove it along with the Ranges map. |
| auto Range = Ranges.lower_bound(Row.Address.Address); |
| if (Range != Ranges.begin() && Range != Ranges.end()) |
| --Range; |
| |
| if (Range != Ranges.end() && Range->first <= Row.Address.Address && |
| Range->second.HighPC >= Row.Address.Address) { |
| StopAddress = Row.Address.Address + Range->second.Offset; |
| } |
| } |
| } |
| if (StopAddress != -1ULL && !Seq.empty()) { |
| // Insert end sequence row with the computed end address, but |
| // the same line as the previous one. |
| auto NextLine = Seq.back(); |
| NextLine.Address.Address = StopAddress; |
| NextLine.EndSequence = 1; |
| NextLine.PrologueEnd = 0; |
| NextLine.BasicBlock = 0; |
| NextLine.EpilogueBegin = 0; |
| Seq.push_back(NextLine); |
| insertLineSequence(Seq, NewRows); |
| } |
| |
| if (!CurrRangeValid) |
| continue; |
| } |
| |
| // Ignore empty sequences. |
| if (Row.EndSequence && Seq.empty()) |
| continue; |
| |
| // Relocate row address and add it to the current sequence. |
| Row.Address.Address += CurrRange.value(); |
| Seq.emplace_back(Row); |
| |
| if (Row.EndSequence) |
| insertLineSequence(Seq, NewRows); |
| } |
| |
| // Finished extracting, now emit the line tables. |
| // FIXME: LLVM hard-codes its prologue values. We just copy the |
| // prologue over and that works because we act as both producer and |
| // consumer. It would be nicer to have a real configurable line |
| // table emitter. |
| if (LineTable.Prologue.getVersion() < 2 || |
| LineTable.Prologue.getVersion() > 5 || |
| LineTable.Prologue.DefaultIsStmt != DWARF2_LINE_DEFAULT_IS_STMT || |
| LineTable.Prologue.OpcodeBase > 13) |
| reportWarning("line table parameters mismatch. Cannot emit.", DMO); |
| else { |
| uint32_t PrologueEnd = *StmtList + 10 + LineTable.Prologue.PrologueLength; |
| // DWARF v5 has an extra 2 bytes of information before the header_length |
| // field. |
| if (LineTable.Prologue.getVersion() == 5) |
| PrologueEnd += 2; |
| StringRef LineData = OrigDwarf.getDWARFObj().getLineSection().Data; |
| MCDwarfLineTableParams Params; |
| Params.DWARF2LineOpcodeBase = LineTable.Prologue.OpcodeBase; |
| Params.DWARF2LineBase = LineTable.Prologue.LineBase; |
| Params.DWARF2LineRange = LineTable.Prologue.LineRange; |
| Streamer->emitLineTableForUnit(Params, |
| LineData.slice(*StmtList + 4, PrologueEnd), |
| LineTable.Prologue.MinInstLength, NewRows, |
| Unit.getOrigUnit().getAddressByteSize()); |
| } |
| } |
| |
| void DwarfLinker::emitAcceleratorEntriesForUnit(CompileUnit &Unit) { |
| switch (Options.TheAccelTableKind) { |
| case AccelTableKind::Apple: |
| emitAppleAcceleratorEntriesForUnit(Unit); |
| break; |
| case AccelTableKind::Dwarf: |
| emitDwarfAcceleratorEntriesForUnit(Unit); |
| break; |
| case AccelTableKind::Default: |
| llvm_unreachable("The default must be updated to a concrete value."); |
| break; |
| } |
| } |
| |
| void DwarfLinker::emitAppleAcceleratorEntriesForUnit(CompileUnit &Unit) { |
| // Add namespaces. |
| for (const auto &Namespace : Unit.getNamespaces()) |
| AppleNamespaces.addName(Namespace.Name, |
| Namespace.Die->getOffset() + Unit.getStartOffset()); |
| |
| /// Add names. |
| if (!Options.Minimize) |
| Streamer->emitPubNamesForUnit(Unit); |
| for (const auto &Pubname : Unit.getPubnames()) |
| AppleNames.addName(Pubname.Name, |
| Pubname.Die->getOffset() + Unit.getStartOffset()); |
| |
| /// Add types. |
| if (!Options.Minimize) |
| Streamer->emitPubTypesForUnit(Unit); |
| for (const auto &Pubtype : Unit.getPubtypes()) |
| AppleTypes.addName( |
| Pubtype.Name, Pubtype.Die->getOffset() + Unit.getStartOffset(), |
| Pubtype.Die->getTag(), |
| Pubtype.ObjcClassImplementation ? dwarf::DW_FLAG_type_implementation |
| : 0, |
| Pubtype.QualifiedNameHash); |
| |
| /// Add ObjC names. |
| for (const auto &ObjC : Unit.getObjC()) |
| AppleObjc.addName(ObjC.Name, ObjC.Die->getOffset() + Unit.getStartOffset()); |
| } |
| |
| void DwarfLinker::emitDwarfAcceleratorEntriesForUnit(CompileUnit &Unit) { |
| for (const auto &Namespace : Unit.getNamespaces()) |
| DebugNames.addName(Namespace.Name, Namespace.Die->getOffset(), |
| Namespace.Die->getTag(), Unit.getUniqueID()); |
| for (const auto &Pubname : Unit.getPubnames()) |
| DebugNames.addName(Pubname.Name, Pubname.Die->getOffset(), |
| Pubname.Die->getTag(), Unit.getUniqueID()); |
| for (const auto &Pubtype : Unit.getPubtypes()) |
| DebugNames.addName(Pubtype.Name, Pubtype.Die->getOffset(), |
| Pubtype.Die->getTag(), Unit.getUniqueID()); |
| } |
| |
| /// Read the frame info stored in the object, and emit the |
| /// patched frame descriptions for the linked binary. |
| /// |
| /// This is actually pretty easy as the data of the CIEs and FDEs can |
| /// be considered as black boxes and moved as is. The only thing to do |
| /// is to patch the addresses in the headers. |
| void DwarfLinker::patchFrameInfoForObject(const DebugMapObject &DMO, |
| RangesTy &Ranges, |
| DWARFContext &OrigDwarf, |
| unsigned AddrSize) { |
| StringRef FrameData = OrigDwarf.getDWARFObj().getDebugFrameSection(); |
| if (FrameData.empty()) |
| return; |
| |
| DataExtractor Data(FrameData, OrigDwarf.isLittleEndian(), 0); |
| uint32_t InputOffset = 0; |
| |
| // Store the data of the CIEs defined in this object, keyed by their |
| // offsets. |
| DenseMap<uint32_t, StringRef> LocalCIES; |
| |
| while (Data.isValidOffset(InputOffset)) { |
| uint32_t EntryOffset = InputOffset; |
| uint32_t InitialLength = Data.getU32(&InputOffset); |
| if (InitialLength == 0xFFFFFFFF) |
| return reportWarning("Dwarf64 bits no supported", DMO); |
| |
| uint32_t CIEId = Data.getU32(&InputOffset); |
| if (CIEId == 0xFFFFFFFF) { |
| // This is a CIE, store it. |
| StringRef CIEData = FrameData.substr(EntryOffset, InitialLength + 4); |
| LocalCIES[EntryOffset] = CIEData; |
| // The -4 is to account for the CIEId we just read. |
| InputOffset += InitialLength - 4; |
| continue; |
| } |
| |
| uint32_t Loc = Data.getUnsigned(&InputOffset, AddrSize); |
| |
| // Some compilers seem to emit frame info that doesn't start at |
| // the function entry point, thus we can't just lookup the address |
| // in the debug map. Use the linker's range map to see if the FDE |
| // describes something that we can relocate. |
| auto Range = Ranges.upper_bound(Loc); |
| if (Range != Ranges.begin()) |
| --Range; |
| if (Range == Ranges.end() || Range->first > Loc || |
| Range->second.HighPC <= Loc) { |
| // The +4 is to account for the size of the InitialLength field itself. |
| InputOffset = EntryOffset + InitialLength + 4; |
| continue; |
| } |
| |
| // This is an FDE, and we have a mapping. |
| // Have we already emitted a corresponding CIE? |
| StringRef CIEData = LocalCIES[CIEId]; |
| if (CIEData.empty()) |
| return reportWarning("Inconsistent debug_frame content. Dropping.", DMO); |
| |
| // Look if we already emitted a CIE that corresponds to the |
| // referenced one (the CIE data is the key of that lookup). |
| auto IteratorInserted = EmittedCIEs.insert( |
| std::make_pair(CIEData, Streamer->getFrameSectionSize())); |
| // If there is no CIE yet for this ID, emit it. |
| if (IteratorInserted.second || |
| // FIXME: dsymutil-classic only caches the last used CIE for |
| // reuse. Mimic that behavior for now. Just removing that |
| // second half of the condition and the LastCIEOffset variable |
| // makes the code DTRT. |
| LastCIEOffset != IteratorInserted.first->getValue()) { |
| LastCIEOffset = Streamer->getFrameSectionSize(); |
| IteratorInserted.first->getValue() = LastCIEOffset; |
| Streamer->emitCIE(CIEData); |
| } |
| |
| // Emit the FDE with updated address and CIE pointer. |
| // (4 + AddrSize) is the size of the CIEId + initial_location |
| // fields that will get reconstructed by emitFDE(). |
| unsigned FDERemainingBytes = InitialLength - (4 + AddrSize); |
| Streamer->emitFDE(IteratorInserted.first->getValue(), AddrSize, |
| Loc + Range->second.Offset, |
| FrameData.substr(InputOffset, FDERemainingBytes)); |
| InputOffset += FDERemainingBytes; |
| } |
| } |
| |
| void DwarfLinker::DIECloner::copyAbbrev( |
| const DWARFAbbreviationDeclaration &Abbrev, bool hasODR) { |
| DIEAbbrev Copy(dwarf::Tag(Abbrev.getTag()), |
| dwarf::Form(Abbrev.hasChildren())); |
| |
| for (const auto &Attr : Abbrev.attributes()) { |
| uint16_t Form = Attr.Form; |
| if (hasODR && isODRAttribute(Attr.Attr)) |
| Form = dwarf::DW_FORM_ref_addr; |
| Copy.AddAttribute(dwarf::Attribute(Attr.Attr), dwarf::Form(Form)); |
| } |
| |
| Linker.AssignAbbrev(Copy); |
| } |
| |
| uint32_t DwarfLinker::DIECloner::hashFullyQualifiedName( |
| DWARFDie DIE, CompileUnit &U, const DebugMapObject &DMO, int RecurseDepth) { |
| const char *Name = nullptr; |
| DWARFUnit *OrigUnit = &U.getOrigUnit(); |
| CompileUnit *CU = &U; |
| Optional<DWARFFormValue> Ref; |
| |
| while (1) { |
| if (const char *CurrentName = DIE.getName(DINameKind::ShortName)) |
| Name = CurrentName; |
| |
| if (!(Ref = DIE.find(dwarf::DW_AT_specification)) && |
| !(Ref = DIE.find(dwarf::DW_AT_abstract_origin))) |
| break; |
| |
| if (!Ref->isFormClass(DWARFFormValue::FC_Reference)) |
| break; |
| |
| CompileUnit *RefCU; |
| if (auto RefDIE = |
| resolveDIEReference(Linker, DMO, CompileUnits, *Ref, DIE, RefCU)) { |
| CU = RefCU; |
| OrigUnit = &RefCU->getOrigUnit(); |
| DIE = RefDIE; |
| } |
| } |
| |
| unsigned Idx = OrigUnit->getDIEIndex(DIE); |
| if (!Name && DIE.getTag() == dwarf::DW_TAG_namespace) |
| Name = "(anonymous namespace)"; |
| |
| if (CU->getInfo(Idx).ParentIdx == 0 || |
| // FIXME: dsymutil-classic compatibility. Ignore modules. |
| CU->getOrigUnit().getDIEAtIndex(CU->getInfo(Idx).ParentIdx).getTag() == |
| dwarf::DW_TAG_module) |
| return djbHash(Name ? Name : "", djbHash(RecurseDepth ? "" : "::")); |
| |
| DWARFDie Die = OrigUnit->getDIEAtIndex(CU->getInfo(Idx).ParentIdx); |
| return djbHash( |
| (Name ? Name : ""), |
| djbHash((Name ? "::" : ""), |
| hashFullyQualifiedName(Die, *CU, DMO, ++RecurseDepth))); |
| } |
| |
| static uint64_t getDwoId(const DWARFDie &CUDie, const DWARFUnit &Unit) { |
| auto DwoId = dwarf::toUnsigned( |
| CUDie.find({dwarf::DW_AT_dwo_id, dwarf::DW_AT_GNU_dwo_id})); |
| if (DwoId) |
| return *DwoId; |
| return 0; |
| } |
| |
| bool DwarfLinker::registerModuleReference( |
| const DWARFDie &CUDie, const DWARFUnit &Unit, DebugMap &ModuleMap, |
| const DebugMapObject &DMO, RangesTy &Ranges, OffsetsStringPool &StringPool, |
| UniquingStringPool &UniquingStringPool, DeclContextTree &ODRContexts, |
| uint64_t ModulesEndOffset, unsigned &UnitID, bool IsLittleEndian, |
| unsigned Indent, bool Quiet) { |
| std::string PCMfile = dwarf::toString( |
| CUDie.find({dwarf::DW_AT_dwo_name, dwarf::DW_AT_GNU_dwo_name}), ""); |
| if (PCMfile.empty()) |
| return false; |
| |
| // Clang module DWARF skeleton CUs abuse this for the path to the module. |
| std::string PCMpath = dwarf::toString(CUDie.find(dwarf::DW_AT_comp_dir), ""); |
| uint64_t DwoId = getDwoId(CUDie, Unit); |
| |
| std::string Name = dwarf::toString(CUDie.find(dwarf::DW_AT_name), ""); |
| if (Name.empty()) { |
| if (!Quiet) |
| reportWarning("Anonymous module skeleton CU for " + PCMfile, DMO); |
| return true; |
| } |
| |
| if (!Quiet && Options.Verbose) { |
| outs().indent(Indent); |
| outs() << "Found clang module reference " << PCMfile; |
| } |
| |
| auto Cached = ClangModules.find(PCMfile); |
| if (Cached != ClangModules.end()) { |
| // FIXME: Until PR27449 (https://llvm.org/bugs/show_bug.cgi?id=27449) is |
| // fixed in clang, only warn about DWO_id mismatches in verbose mode. |
| // ASTFileSignatures will change randomly when a module is rebuilt. |
| if (!Quiet && Options.Verbose && (Cached->second != DwoId)) |
| reportWarning(Twine("hash mismatch: this object file was built against a " |
| "different version of the module ") + |
| PCMfile, |
| DMO); |
| if (!Quiet && Options.Verbose) |
| outs() << " [cached].\n"; |
| return true; |
| } |
| if (!Quiet && Options.Verbose) |
| outs() << " ...\n"; |
| |
| // Cyclic dependencies are disallowed by Clang, but we still |
| // shouldn't run into an infinite loop, so mark it as processed now. |
| ClangModules.insert({PCMfile, DwoId}); |
| if (Error E = loadClangModule(PCMfile, PCMpath, Name, DwoId, ModuleMap, DMO, |
| Ranges, StringPool, UniquingStringPool, |
| ODRContexts, ModulesEndOffset, UnitID, |
| IsLittleEndian, Indent + 2, Quiet)) { |
| consumeError(std::move(E)); |
| return false; |
| } |
| return true; |
| } |
| |
| ErrorOr<const object::ObjectFile &> |
| DwarfLinker::loadObject(const DebugMapObject &Obj, const DebugMap &Map) { |
| auto ObjectEntry = |
| BinHolder.getObjectEntry(Obj.getObjectFilename(), Obj.getTimestamp()); |
| if (!ObjectEntry) { |
| auto Err = ObjectEntry.takeError(); |
| reportWarning( |
| Twine(Obj.getObjectFilename()) + ": " + toString(std::move(Err)), Obj); |
| return errorToErrorCode(std::move(Err)); |
| } |
| |
| auto Object = ObjectEntry->getObject(Map.getTriple()); |
| if (!Object) { |
| auto Err = Object.takeError(); |
| reportWarning( |
| Twine(Obj.getObjectFilename()) + ": " + toString(std::move(Err)), Obj); |
| return errorToErrorCode(std::move(Err)); |
| } |
| |
| return *Object; |
| } |
| |
| Error DwarfLinker::loadClangModule( |
| StringRef Filename, StringRef ModulePath, StringRef ModuleName, |
| uint64_t DwoId, DebugMap &ModuleMap, const DebugMapObject &DMO, |
| RangesTy &Ranges, OffsetsStringPool &StringPool, |
| UniquingStringPool &UniquingStringPool, DeclContextTree &ODRContexts, |
| uint64_t ModulesEndOffset, unsigned &UnitID, bool IsLittleEndian, |
| unsigned Indent, bool Quiet) { |
| SmallString<80> Path(Options.PrependPath); |
| if (sys::path::is_relative(Filename)) |
| sys::path::append(Path, ModulePath, Filename); |
| else |
| sys::path::append(Path, Filename); |
| // Don't use the cached binary holder because we have no thread-safety |
| // guarantee and the lifetime is limited. |
| auto &Obj = ModuleMap.addDebugMapObject( |
| Path, sys::TimePoint<std::chrono::seconds>(), MachO::N_OSO); |
| auto ErrOrObj = loadObject(Obj, ModuleMap); |
| if (!ErrOrObj) { |
| // Try and emit more helpful warnings by applying some heuristics. |
| StringRef ObjFile = DMO.getObjectFilename(); |
| bool isClangModule = sys::path::extension(Filename).equals(".pcm"); |
| bool isArchive = ObjFile.endswith(")"); |
| if (isClangModule) { |
| StringRef ModuleCacheDir = sys::path::parent_path(Path); |
| if (sys::fs::exists(ModuleCacheDir)) { |
| // If the module's parent directory exists, we assume that the module |
| // cache has expired and was pruned by clang. A more adventurous |
| // dsymutil would invoke clang to rebuild the module now. |
| if (!ModuleCacheHintDisplayed) { |
| WithColor::note() << "The clang module cache may have expired since " |
| "this object file was built. Rebuilding the " |
| "object file will rebuild the module cache.\n"; |
| ModuleCacheHintDisplayed = true; |
| } |
| } else if (isArchive) { |
| // If the module cache directory doesn't exist at all and the object |
| // file is inside a static library, we assume that the static library |
| // was built on a different machine. We don't want to discourage module |
| // debugging for convenience libraries within a project though. |
| if (!ArchiveHintDisplayed) { |
| WithColor::note() |
| << "Linking a static library that was built with " |
| "-gmodules, but the module cache was not found. " |
| "Redistributable static libraries should never be " |
| "built with module debugging enabled. The debug " |
| "experience will be degraded due to incomplete " |
| "debug information.\n"; |
| ArchiveHintDisplayed = true; |
| } |
| } |
| } |
| return Error::success(); |
| } |
| |
| std::unique_ptr<CompileUnit> Unit; |
| |
| // Setup access to the debug info. |
| auto DwarfContext = DWARFContext::create(*ErrOrObj); |
| RelocationManager RelocMgr(*this); |
| |
| for (const auto &CU : DwarfContext->compile_units()) { |
| updateDwarfVersion(CU->getVersion()); |
| // Recursively get all modules imported by this one. |
| auto CUDie = CU->getUnitDIE(false); |
| if (!CUDie) |
| continue; |
| if (!registerModuleReference(CUDie, *CU, ModuleMap, DMO, Ranges, StringPool, |
| UniquingStringPool, ODRContexts, |
| ModulesEndOffset, UnitID, IsLittleEndian, |
| Indent, Quiet)) { |
| if (Unit) { |
| std::string Err = |
| (Filename + |
| ": Clang modules are expected to have exactly 1 compile unit.\n") |
| .str(); |
| error(Err); |
| return make_error<StringError>(Err, inconvertibleErrorCode()); |
| } |
| // FIXME: Until PR27449 (https://llvm.org/bugs/show_bug.cgi?id=27449) is |
| // fixed in clang, only warn about DWO_id mismatches in verbose mode. |
| // ASTFileSignatures will change randomly when a module is rebuilt. |
| uint64_t PCMDwoId = getDwoId(CUDie, *CU); |
| if (PCMDwoId != DwoId) { |
| if (!Quiet && Options.Verbose) |
| reportWarning( |
| Twine("hash mismatch: this object file was built against a " |
| "different version of the module ") + |
| Filename, |
| DMO); |
| // Update the cache entry with the DwoId of the module loaded from disk. |
| ClangModules[Filename] = PCMDwoId; |
| } |
| |
| // Add this module. |
| Unit = llvm::make_unique<CompileUnit>(*CU, UnitID++, !Options.NoODR, |
| ModuleName); |
| Unit->setHasInterestingContent(); |
| analyzeContextInfo(CUDie, 0, *Unit, &ODRContexts.getRoot(), |
| UniquingStringPool, ODRContexts, ModulesEndOffset); |
| // Keep everything. |
| Unit->markEverythingAsKept(); |
| } |
| } |
| if (!Unit->getOrigUnit().getUnitDIE().hasChildren()) |
| return Error::success(); |
| if (!Quiet && Options.Verbose) { |
| outs().indent(Indent); |
| outs() << "cloning .debug_info from " << Filename << "\n"; |
| } |
| |
| UnitListTy CompileUnits; |
| CompileUnits.push_back(std::move(Unit)); |
| DIECloner(*this, RelocMgr, DIEAlloc, CompileUnits, Options) |
| .cloneAllCompileUnits(*DwarfContext, DMO, Ranges, StringPool, |
| IsLittleEndian); |
| return Error::success(); |
| } |
| |
| void DwarfLinker::DIECloner::cloneAllCompileUnits( |
| DWARFContext &DwarfContext, const DebugMapObject &DMO, RangesTy &Ranges, |
| OffsetsStringPool &StringPool, bool IsLittleEndian) { |
| if (!Linker.Streamer) |
| return; |
| |
| for (auto &CurrentUnit : CompileUnits) { |
| auto InputDIE = CurrentUnit->getOrigUnit().getUnitDIE(); |
| CurrentUnit->setStartOffset(Linker.OutputDebugInfoSize); |
| if (!InputDIE) { |
| Linker.OutputDebugInfoSize = CurrentUnit->computeNextUnitOffset(); |
| continue; |
| } |
| if (CurrentUnit->getInfo(0).Keep) { |
| // Clone the InputDIE into your Unit DIE in our compile unit since it |
| // already has a DIE inside of it. |
| CurrentUnit->createOutputDIE(); |
| cloneDIE(InputDIE, DMO, *CurrentUnit, StringPool, 0 /* PC offset */, |
| 11 /* Unit Header size */, 0, IsLittleEndian, |
| CurrentUnit->getOutputUnitDIE()); |
| } |
| |
| Linker.OutputDebugInfoSize = CurrentUnit->computeNextUnitOffset(); |
| |
| if (Linker.Options.NoOutput) |
| continue; |
| |
| // FIXME: for compatibility with the classic dsymutil, we emit |
| // an empty line table for the unit, even if the unit doesn't |
| // actually exist in the DIE tree. |
| if (LLVM_LIKELY(!Linker.Options.Update) || Linker.Options.Translator) |
| Linker.patchLineTableForUnit(*CurrentUnit, DwarfContext, Ranges, DMO); |
| |
| Linker.emitAcceleratorEntriesForUnit(*CurrentUnit); |
| |
| if (LLVM_UNLIKELY(Linker.Options.Update)) |
| continue; |
| |
| Linker.patchRangesForUnit(*CurrentUnit, DwarfContext, DMO); |
| auto ProcessExpr = [&](StringRef Bytes, SmallVectorImpl<uint8_t> &Buffer) { |
| DWARFUnit &OrigUnit = CurrentUnit->getOrigUnit(); |
| DataExtractor Data(Bytes, IsLittleEndian, OrigUnit.getAddressByteSize()); |
| cloneExpression(Data, |
| DWARFExpression(Data, OrigUnit.getVersion(), |
| OrigUnit.getAddressByteSize()), |
| DMO, *CurrentUnit, Buffer); |
| }; |
| Linker.Streamer->emitLocationsForUnit(*CurrentUnit, DwarfContext, |
| ProcessExpr); |
| } |
| |
| if (Linker.Options.NoOutput) |
| return; |
| |
| // Emit all the compile unit's debug information. |
| for (auto &CurrentUnit : CompileUnits) { |
| if (LLVM_LIKELY(!Linker.Options.Update)) |
| Linker.generateUnitRanges(*CurrentUnit); |
| |
| CurrentUnit->fixupForwardReferences(); |
| |
| if (!CurrentUnit->getOutputUnitDIE()) |
| continue; |
| |
| Linker.Streamer->emitCompileUnitHeader(*CurrentUnit); |
| Linker.Streamer->emitDIE(*CurrentUnit->getOutputUnitDIE()); |
| } |
| } |
| |
| void DwarfLinker::updateAccelKind(DWARFContext &Dwarf) { |
| if (Options.TheAccelTableKind != AccelTableKind::Default) |
| return; |
| |
| auto &DwarfObj = Dwarf.getDWARFObj(); |
| |
| if (!AtLeastOneDwarfAccelTable && |
| (!DwarfObj.getAppleNamesSection().Data.empty() || |
| !DwarfObj.getAppleTypesSection().Data.empty() || |
| !DwarfObj.getAppleNamespacesSection().Data.empty() || |
| !DwarfObj.getAppleObjCSection().Data.empty())) { |
| AtLeastOneAppleAccelTable = true; |
| } |
| |
| if (!AtLeastOneDwarfAccelTable && |
| !DwarfObj.getDebugNamesSection().Data.empty()) { |
| AtLeastOneDwarfAccelTable = true; |
| } |
| } |
| |
| bool DwarfLinker::emitPaperTrailWarnings(const DebugMapObject &DMO, |
| const DebugMap &Map, |
| OffsetsStringPool &StringPool) { |
| if (DMO.getWarnings().empty() || !DMO.empty()) |
| return false; |
| |
| Streamer->switchToDebugInfoSection(/* Version */ 2); |
| DIE *CUDie = DIE::get(DIEAlloc, dwarf::DW_TAG_compile_unit); |
| CUDie->setOffset(11); |
| StringRef Producer = StringPool.internString("dsymutil"); |
| StringRef File = StringPool.internString(DMO.getObjectFilename()); |
| CUDie->addValue(DIEAlloc, dwarf::DW_AT_producer, dwarf::DW_FORM_strp, |
| DIEInteger(StringPool.getStringOffset(Producer))); |
| DIEBlock *String = new (DIEAlloc) DIEBlock(); |
| DIEBlocks.push_back(String); |
| for (auto &C : File) |
| String->addValue(DIEAlloc, dwarf::Attribute(0), dwarf::DW_FORM_data1, |
| DIEInteger(C)); |
| String->addValue(DIEAlloc, dwarf::Attribute(0), dwarf::DW_FORM_data1, |
| DIEInteger(0)); |
| |
| CUDie->addValue(DIEAlloc, dwarf::DW_AT_name, dwarf::DW_FORM_string, String); |
| for (const auto &Warning : DMO.getWarnings()) { |
| DIE &ConstDie = CUDie->addChild(DIE::get(DIEAlloc, dwarf::DW_TAG_constant)); |
| ConstDie.addValue( |
| DIEAlloc, dwarf::DW_AT_name, dwarf::DW_FORM_strp, |
| DIEInteger(StringPool.getStringOffset("dsymutil_warning"))); |
| ConstDie.addValue(DIEAlloc, dwarf::DW_AT_artificial, dwarf::DW_FORM_flag, |
| DIEInteger(1)); |
| ConstDie.addValue(DIEAlloc, dwarf::DW_AT_const_value, dwarf::DW_FORM_strp, |
| DIEInteger(StringPool.getStringOffset(Warning))); |
| } |
| unsigned Size = 4 /* FORM_strp */ + File.size() + 1 + |
| DMO.getWarnings().size() * (4 + 1 + 4) + |
| 1 /* End of children */; |
| DIEAbbrev Abbrev = CUDie->generateAbbrev(); |
| AssignAbbrev(Abbrev); |
| CUDie->setAbbrevNumber(Abbrev.getNumber()); |
| Size += getULEB128Size(Abbrev.getNumber()); |
| // Abbreviation ordering needed for classic compatibility. |
| for (auto &Child : CUDie->children()) { |
| Abbrev = Child.generateAbbrev(); |
| AssignAbbrev(Abbrev); |
| Child.setAbbrevNumber(Abbrev.getNumber()); |
| Size += getULEB128Size(Abbrev.getNumber()); |
| } |
| CUDie->setSize(Size); |
| auto &Asm = Streamer->getAsmPrinter(); |
| Asm.emitInt32(11 + CUDie->getSize() - 4); |
| Asm.emitInt16(2); |
| Asm.emitInt32(0); |
| Asm.emitInt8(Map.getTriple().isArch64Bit() ? 8 : 4); |
| Streamer->emitDIE(*CUDie); |
| OutputDebugInfoSize += 11 /* Header */ + Size; |
| |
| return true; |
| } |
| |
| bool DwarfLinker::link(const DebugMap &Map) { |
| if (!createStreamer(Map.getTriple(), OutFile)) |
| return false; |
| |
| // Size of the DIEs (and headers) generated for the linked output. |
| OutputDebugInfoSize = 0; |
| // A unique ID that identifies each compile unit. |
| unsigned UnitID = 0; |
| DebugMap ModuleMap(Map.getTriple(), Map.getBinaryPath()); |
| |
| // First populate the data structure we need for each iteration of the |
| // parallel loop. |
| unsigned NumObjects = Map.getNumberOfObjects(); |
| std::vector<LinkContext> ObjectContexts; |
| ObjectContexts.reserve(NumObjects); |
| for (const auto &Obj : Map.objects()) { |
| ObjectContexts.emplace_back(Map, *this, *Obj.get()); |
| LinkContext &LC = ObjectContexts.back(); |
| if (LC.ObjectFile) |
| updateAccelKind(*LC.DwarfContext); |
| } |
| |
| // This Dwarf string pool which is only used for uniquing. This one should |
| // never be used for offsets as its not thread-safe or predictable. |
| UniquingStringPool UniquingStringPool; |
| |
| // This Dwarf string pool which is used for emission. It must be used |
| // serially as the order of calling getStringOffset matters for |
| // reproducibility. |
| OffsetsStringPool OffsetsStringPool(Options.Translator); |
| |
| // ODR Contexts for the link. |
| DeclContextTree ODRContexts; |
| |
| // If we haven't decided on an accelerator table kind yet, we base ourselves |
| // on the DWARF we have seen so far. At this point we haven't pulled in debug |
| // information from modules yet, so it is technically possible that they |
| // would affect the decision. However, as they're built with the same |
| // compiler and flags, it is safe to assume that they will follow the |
| // decision made here. |
| if (Options.TheAccelTableKind == AccelTableKind::Default) { |
| if (AtLeastOneDwarfAccelTable && !AtLeastOneAppleAccelTable) |
| Options.TheAccelTableKind = AccelTableKind::Dwarf; |
| else |
| Options.TheAccelTableKind = AccelTableKind::Apple; |
| } |
| |
| for (LinkContext &LinkContext : ObjectContexts) { |
| if (Options.Verbose) |
| outs() << "DEBUG MAP OBJECT: " << LinkContext.DMO.getObjectFilename() |
| << "\n"; |
| |
| // N_AST objects (swiftmodule files) should get dumped directly into the |
| // appropriate DWARF section. |
| if (LinkContext.DMO.getType() == MachO::N_AST) { |
| StringRef File = LinkContext.DMO.getObjectFilename(); |
| auto ErrorOrMem = MemoryBuffer::getFile(File); |
| if (!ErrorOrMem) { |
| warn("Could not open '" + File + "'\n"); |
| continue; |
| } |
| sys::fs::file_status Stat; |
| if (auto Err = sys::fs::status(File, Stat)) { |
| warn(Err.message()); |
| continue; |
| } |
| if (!Options.NoTimestamp) { |
| // The modification can have sub-second precision so we need to cast |
| // away the extra precision that's not present in the debug map. |
| auto ModificationTime = |
| std::chrono::time_point_cast<std::chrono::seconds>( |
| Stat.getLastModificationTime()); |
| if (ModificationTime != LinkContext.DMO.getTimestamp()) { |
| // Not using the helper here as we can easily stream TimePoint<>. |
| WithColor::warning() |
| << "Timestamp mismatch for " << File << ": " |
| << Stat.getLastModificationTime() << " and " |
| << sys::TimePoint<>(LinkContext.DMO.getTimestamp()) << "\n"; |
| continue; |
| } |
| } |
| |
| // Copy the module into the .swift_ast section. |
| if (!Options.NoOutput) |
| Streamer->emitSwiftAST((*ErrorOrMem)->getBuffer()); |
| continue; |
| } |
| |
| if (emitPaperTrailWarnings(LinkContext.DMO, Map, OffsetsStringPool)) |
| continue; |
| |
| if (!LinkContext.ObjectFile) |
| continue; |
| |
| // Look for relocations that correspond to debug map entries. |
| |
| if (LLVM_LIKELY(!Options.Update) && |
| !LinkContext.RelocMgr.findValidRelocsInDebugInfo( |
| *LinkContext.ObjectFile, LinkContext.DMO)) { |
| if (Options.Verbose) |
| outs() << "No valid relocations found. Skipping.\n"; |
| |
| // Clear this ObjFile entry as a signal to other loops that we should not |
| // process this iteration. |
| LinkContext.ObjectFile = nullptr; |
| continue; |
| } |
| |
| // Setup access to the debug info. |
| if (!LinkContext.DwarfContext) |
| continue; |
| |
| startDebugObject(LinkContext); |
| |
| // In a first phase, just read in the debug info and load all clang modules. |
| LinkContext.CompileUnits.reserve( |
| LinkContext.DwarfContext->getNumCompileUnits()); |
| |
| for (const auto &CU : LinkContext.DwarfContext->compile_units()) { |
| updateDwarfVersion(CU->getVersion()); |
| auto CUDie = CU->getUnitDIE(false); |
| if (Options.Verbose) { |
| outs() << "Input compilation unit:"; |
| DIDumpOptions DumpOpts; |
| DumpOpts.RecurseDepth = 0; |
| DumpOpts.Verbose = Options.Verbose; |
| CUDie.dump(outs(), 0, DumpOpts); |
| } |
| if (CUDie && !LLVM_UNLIKELY(Options.Update)) |
| registerModuleReference(CUDie, *CU, ModuleMap, LinkContext.DMO, |
| LinkContext.Ranges, OffsetsStringPool, |
| UniquingStringPool, ODRContexts, 0, UnitID, |
| LinkContext.DwarfContext->isLittleEndian()); |
|