X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=tools%2Fdsymutil%2FDwarfLinker.cpp;h=7ac6f8ed5e3d6247f40d93dd75057b246b14b825;hb=accfde3ad612bb30e426b1bc13760549a28fd9df;hp=bcdd9cb7c03d9edf0badb77c3c25d21c09fb6595;hpb=b36506466fd02d583381fa986b6aa9c97a7e045e;p=oota-llvm.git diff --git a/tools/dsymutil/DwarfLinker.cpp b/tools/dsymutil/DwarfLinker.cpp index bcdd9cb7c03..7ac6f8ed5e3 100644 --- a/tools/dsymutil/DwarfLinker.cpp +++ b/tools/dsymutil/DwarfLinker.cpp @@ -10,8 +10,14 @@ #include "BinaryHolder.h" #include "DebugMap.h" #include "dsymutil.h" +#include "MachOUtils.h" +#include "NonRelocatableStringpool.h" +#include "llvm/ADT/IntervalMap.h" +#include "llvm/ADT/StringMap.h" +#include "llvm/ADT/STLExtras.h" #include "llvm/CodeGen/AsmPrinter.h" #include "llvm/CodeGen/DIE.h" +#include "llvm/Config/config.h" #include "llvm/DebugInfo/DWARF/DWARFContext.h" #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h" #include "llvm/DebugInfo/DWARF/DWARFFormValue.h" @@ -19,10 +25,12 @@ #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCContext.h" #include "llvm/MC/MCCodeEmitter.h" +#include "llvm/MC/MCDwarf.h" #include "llvm/MC/MCInstrInfo.h" #include "llvm/MC/MCObjectFileInfo.h" #include "llvm/MC/MCRegisterInfo.h" #include "llvm/MC/MCStreamer.h" +#include "llvm/MC/MCSubtargetInfo.h" #include "llvm/Object/MachO.h" #include "llvm/Support/Dwarf.h" #include "llvm/Support/LEB128.h" @@ -30,22 +38,145 @@ #include "llvm/Target/TargetMachine.h" #include "llvm/Target/TargetOptions.h" #include +#include namespace llvm { namespace dsymutil { namespace { -void warn(const Twine &Warning, const Twine &Context) { - errs() << Twine("while processing ") + Context + ":\n"; - errs() << Twine("warning: ") + Warning + "\n"; -} +template +using HalfOpenIntervalMap = + IntervalMap::LeafSize, + IntervalMapHalfOpenInfo>; -bool error(const Twine &Error, const Twine &Context) { - errs() << Twine("while processing ") + Context + ":\n"; - errs() << Twine("error: ") + Error + "\n"; - return false; -} +typedef HalfOpenIntervalMap FunctionIntervals; + +// FIXME: Delete this structure. +struct PatchLocation { + DIE::value_iterator I; + + PatchLocation() = default; + PatchLocation(DIE::value_iterator I) : I(I) {} + + void set(uint64_t New) const { + assert(I); + const auto &Old = *I; + assert(Old.getType() == DIEValue::isInteger); + *I = DIEValue(Old.getAttribute(), Old.getForm(), DIEInteger(New)); + } + + uint64_t get() const { + assert(I); + return I->getDIEInteger().getValue(); + } +}; + +class CompileUnit; +struct DeclMapInfo; + +/// A DeclContext is a named program scope that is used for ODR +/// uniquing of types. +/// The set of DeclContext for the ODR-subject parts of a Dwarf link +/// is expanded (and uniqued) with each new object file processed. We +/// need to determine the context of each DIE in an linked object file +/// to see if the corresponding type has already been emitted. +/// +/// The contexts are conceptually organised as a tree (eg. a function +/// scope is contained in a namespace scope that contains other +/// scopes), but storing/accessing them in an actual tree is too +/// inefficient: we need to be able to very quickly query a context +/// for a given child context by name. Storing a StringMap in each +/// DeclContext would be too space inefficient. +/// The solution here is to give each DeclContext a link to its parent +/// (this allows to walk up the tree), but to query the existance of a +/// specific DeclContext using a separate DenseMap keyed on the hash +/// of the fully qualified name of the context. +class DeclContext { + unsigned QualifiedNameHash; + uint32_t Line; + uint32_t ByteSize; + uint16_t Tag; + StringRef Name; + StringRef File; + const DeclContext &Parent; + const DWARFDebugInfoEntryMinimal *LastSeenDIE; + uint32_t LastSeenCompileUnitID; + uint32_t CanonicalDIEOffset; + + friend DeclMapInfo; + +public: + typedef DenseSet Map; + + DeclContext() + : QualifiedNameHash(0), Line(0), ByteSize(0), + Tag(dwarf::DW_TAG_compile_unit), Name(), File(), Parent(*this), + LastSeenDIE(nullptr), LastSeenCompileUnitID(0), CanonicalDIEOffset(0) {} + + DeclContext(unsigned Hash, uint32_t Line, uint32_t ByteSize, uint16_t Tag, + StringRef Name, StringRef File, const DeclContext &Parent, + const DWARFDebugInfoEntryMinimal *LastSeenDIE = nullptr, + unsigned CUId = 0) + : QualifiedNameHash(Hash), Line(Line), ByteSize(ByteSize), Tag(Tag), + Name(Name), File(File), Parent(Parent), LastSeenDIE(LastSeenDIE), + LastSeenCompileUnitID(CUId), CanonicalDIEOffset(0) {} + + uint32_t getQualifiedNameHash() const { return QualifiedNameHash; } + + bool setLastSeenDIE(CompileUnit &U, const DWARFDebugInfoEntryMinimal *Die); + + uint32_t getCanonicalDIEOffset() const { return CanonicalDIEOffset; } + void setCanonicalDIEOffset(uint32_t Offset) { CanonicalDIEOffset = Offset; } + + uint16_t getTag() const { return Tag; } + StringRef getName() const { return Name; } +}; + +/// Info type for the DenseMap storing the DeclContext pointers. +struct DeclMapInfo : private DenseMapInfo { + using DenseMapInfo::getEmptyKey; + using DenseMapInfo::getTombstoneKey; + + static unsigned getHashValue(const DeclContext *Ctxt) { + return Ctxt->QualifiedNameHash; + } + + static bool isEqual(const DeclContext *LHS, const DeclContext *RHS) { + if (RHS == getEmptyKey() || RHS == getTombstoneKey()) + return RHS == LHS; + return LHS->QualifiedNameHash == RHS->QualifiedNameHash && + LHS->Line == RHS->Line && LHS->ByteSize == RHS->ByteSize && + LHS->Name.data() == RHS->Name.data() && + LHS->File.data() == RHS->File.data() && + LHS->Parent.QualifiedNameHash == RHS->Parent.QualifiedNameHash; + } +}; + +/// This class gives a tree-like API to the DenseMap that stores the +/// DeclContext objects. It also holds the BumpPtrAllocator where +/// these objects will be allocated. +class DeclContextTree { + BumpPtrAllocator Allocator; + DeclContext Root; + DeclContext::Map Contexts; + +public: + /// Get the child of \a Context described by \a DIE in \a Unit. The + /// required strings will be interned in \a StringPool. + /// \returns The child DeclContext along with one bit that is set if + /// this context is invalid. + /// An invalid context means it shouldn't be considered for uniquing, but its + /// not returning null, because some children of that context might be + /// uniquing candidates. FIXME: The invalid bit along the return value is to + /// emulate some dsymutil-classic functionality. + PointerIntPair + getChildDeclContext(DeclContext &Context, + const DWARFDebugInfoEntryMinimal *DIE, CompileUnit &Unit, + NonRelocatableStringpool &StringPool, bool InClangModule); + + DeclContext &getRoot() { return Root; } +}; /// \brief Stores all information relating to a compile unit, be it in /// its original instance in the object file to its brand new cloned @@ -54,67 +185,214 @@ class CompileUnit { public: /// \brief Information gathered about a DIE in the object file. struct DIEInfo { - uint64_t Address; ///< Linked address of the described entity. + int64_t AddrAdjust; ///< Address offset to apply to the described entity. + DeclContext *Ctxt; ///< ODR Declaration context. DIE *Clone; ///< Cloned version of that DIE. uint32_t ParentIdx; ///< The index of this DIE's parent. - bool Keep; ///< Is the DIE part of the linked output? - bool InDebugMap; ///< Was this DIE's entity found in the map? + bool Keep : 1; ///< Is the DIE part of the linked output? + bool InDebugMap : 1;///< Was this DIE's entity found in the map? + bool Prune : 1; ///< Is this a pure forward declaration we can strip? }; - CompileUnit(DWARFUnit &OrigUnit) : OrigUnit(OrigUnit) { + CompileUnit(DWARFUnit &OrigUnit, unsigned ID, bool CanUseODR, + StringRef ClangModuleName) + : OrigUnit(OrigUnit), ID(ID), LowPc(UINT64_MAX), HighPc(0), RangeAlloc(), + Ranges(RangeAlloc), ClangModuleName(ClangModuleName) { Info.resize(OrigUnit.getNumDIEs()); + + const auto *CUDie = OrigUnit.getUnitDIE(false); + unsigned Lang = CUDie->getAttributeValueAsUnsignedConstant( + &OrigUnit, dwarf::DW_AT_language, 0); + HasODR = CanUseODR && (Lang == dwarf::DW_LANG_C_plus_plus || + Lang == dwarf::DW_LANG_C_plus_plus_03 || + Lang == dwarf::DW_LANG_C_plus_plus_11 || + Lang == dwarf::DW_LANG_C_plus_plus_14 || + Lang == dwarf::DW_LANG_ObjC_plus_plus); } - // Workaround MSVC not supporting implicit move ops CompileUnit(CompileUnit &&RHS) : OrigUnit(RHS.OrigUnit), Info(std::move(RHS.Info)), CUDie(std::move(RHS.CUDie)), StartOffset(RHS.StartOffset), - NextUnitOffset(RHS.NextUnitOffset) {} + NextUnitOffset(RHS.NextUnitOffset), RangeAlloc(), Ranges(RangeAlloc) { + // The CompileUnit container has been 'reserve()'d with the right + // size. We cannot move the IntervalMap anyway. + llvm_unreachable("CompileUnits should not be moved."); + } DWARFUnit &getOrigUnit() const { return OrigUnit; } - DIE *getOutputUnitDIE() const { return CUDie.get(); } - void setOutputUnitDIE(DIE *Die) { CUDie.reset(Die); } + unsigned getUniqueID() const { return ID; } + + DIE *getOutputUnitDIE() const { return CUDie; } + void setOutputUnitDIE(DIE *Die) { CUDie = Die; } + + bool hasODR() const { return HasODR; } + bool isClangModule() const { return !ClangModuleName.empty(); } + const std::string &getClangModuleName() const { return ClangModuleName; } DIEInfo &getInfo(unsigned Idx) { return Info[Idx]; } const DIEInfo &getInfo(unsigned Idx) const { return Info[Idx]; } uint64_t getStartOffset() const { return StartOffset; } uint64_t getNextUnitOffset() const { return NextUnitOffset; } - void setStartOffset(uint64_t DebugInfoSize) { StartOffset = DebugInfoSize; } + uint64_t getLowPc() const { return LowPc; } + uint64_t getHighPc() const { return HighPc; } + + Optional getUnitRangesAttribute() const { + return UnitRangeAttribute; + } + const FunctionIntervals &getFunctionRanges() const { return Ranges; } + const std::vector &getRangesAttributes() const { + return RangeAttributes; + } + + const std::vector> & + getLocationAttributes() const { + return LocationAttributes; + } + + void setHasInterestingContent() { HasInterestingContent = true; } + bool hasInterestingContent() { return HasInterestingContent; } + + /// Mark every DIE in this unit as kept. This function also + /// marks variables as InDebugMap so that they appear in the + /// reconstructed accelerator tables. + void markEverythingAsKept(); + /// \brief Compute the end offset for this unit. Must be /// called after the CU's DIEs have been cloned. /// \returns the next unit offset (which is also the current /// debug_info section size). uint64_t computeNextUnitOffset(); - /// \brief Keep track of a forward reference to DIE \p Die by - /// \p Attr. The attribute should be fixed up later to point to the - /// absolute offset of \p Die in the debug_info section. - void noteForwardReference(DIE *Die, DIEInteger *Attr); + /// \brief Keep track of a forward reference to DIE \p Die in \p + /// RefUnit by \p Attr. The attribute should be fixed up later to + /// point to the absolute offset of \p Die in the debug_info section + /// or to the canonical offset of \p Ctxt if it is non-null. + void noteForwardReference(DIE *Die, const CompileUnit *RefUnit, + DeclContext *Ctxt, PatchLocation Attr); /// \brief Apply all fixups recored by noteForwardReference(). void fixupForwardReferences(); + /// \brief Add a function range [\p LowPC, \p HighPC) that is + /// relocatad by applying offset \p PCOffset. + void addFunctionRange(uint64_t LowPC, uint64_t HighPC, int64_t PCOffset); + + /// \brief Keep track of a DW_AT_range attribute that we will need to + /// patch up later. + void noteRangeAttribute(const DIE &Die, PatchLocation Attr); + + /// \brief Keep track of a location attribute pointing to a location + /// list in the debug_loc section. + void noteLocationAttribute(PatchLocation Attr, int64_t PcOffset); + + /// \brief Add a name accelerator entry for \p Die with \p Name + /// which is stored in the string table at \p Offset. + void addNameAccelerator(const DIE *Die, const char *Name, uint32_t Offset, + bool SkipPubnamesSection = false); + + /// \brief Add a type accelerator entry for \p Die with \p Name + /// which is stored in the string table at \p Offset. + void addTypeAccelerator(const DIE *Die, const char *Name, uint32_t Offset); + + struct AccelInfo { + StringRef Name; ///< Name of the entry. + const DIE *Die; ///< DIE this entry describes. + uint32_t NameOffset; ///< Offset of Name in the string pool. + bool SkipPubSection; ///< Emit this entry only in the apple_* sections. + + AccelInfo(StringRef Name, const DIE *Die, uint32_t NameOffset, + bool SkipPubSection = false) + : Name(Name), Die(Die), NameOffset(NameOffset), + SkipPubSection(SkipPubSection) {} + }; + + const std::vector &getPubnames() const { return Pubnames; } + const std::vector &getPubtypes() const { return Pubtypes; } + + /// Get the full path for file \a FileNum in the line table + const char *getResolvedPath(unsigned FileNum) { + if (FileNum >= ResolvedPaths.size()) + return nullptr; + return ResolvedPaths[FileNum].size() ? ResolvedPaths[FileNum].c_str() + : nullptr; + } + + /// Set the fully resolved path for the line-table's file \a FileNum + /// to \a Path. + void setResolvedPath(unsigned FileNum, const std::string &Path) { + if (ResolvedPaths.size() <= FileNum) + ResolvedPaths.resize(FileNum + 1); + ResolvedPaths[FileNum] = Path; + } + private: DWARFUnit &OrigUnit; - std::vector Info; ///< DIE info indexed by DIE index. - std::unique_ptr CUDie; ///< Root of the linked DIE tree. + unsigned ID; + std::vector Info; ///< DIE info indexed by DIE index. + DIE *CUDie; ///< Root of the linked DIE tree. uint64_t StartOffset; uint64_t NextUnitOffset; + uint64_t LowPc; + uint64_t HighPc; + /// \brief A list of attributes to fixup with the absolute offset of /// a DIE in the debug_info section. /// /// The offsets for the attributes in this array couldn't be set while - /// cloning because for forward refences the target DIE's offset isn't - /// known you emit the reference attribute. - std::vector> ForwardDIEReferences; + /// cloning because for cross-cu forward refences the target DIE's + /// offset isn't known you emit the reference attribute. + std::vector> ForwardDIEReferences; + + FunctionIntervals::Allocator RangeAlloc; + /// \brief The ranges in that interval map are the PC ranges for + /// functions in this unit, associated with the PC offset to apply + /// to the addresses to get the linked address. + FunctionIntervals Ranges; + + /// \brief DW_AT_ranges attributes to patch after we have gathered + /// all the unit's function addresses. + /// @{ + std::vector RangeAttributes; + Optional UnitRangeAttribute; + /// @} + + /// \brief Location attributes that need to be transfered from th + /// original debug_loc section to the liked one. They are stored + /// along with the PC offset that is to be applied to their + /// function's address. + std::vector> LocationAttributes; + + /// \brief Accelerator entries for the unit, both for the pub* + /// sections and the apple* ones. + /// @{ + std::vector Pubnames; + std::vector Pubtypes; + /// @} + + /// Cached resolved paths from the line table. + std::vector ResolvedPaths; + + /// Is this unit subject to the ODR rule? + bool HasODR; + /// Did a DIE actually contain a valid reloc? + bool HasInterestingContent; + /// If this is a Clang module, this holds the module's name. + std::string ClangModuleName; }; +void CompileUnit::markEverythingAsKept() { + for (auto &I : Info) + // Mark everything that wasn't explicity marked for pruning. + I.Keep = !I.Prune; +} + uint64_t CompileUnit::computeNextUnitOffset() { NextUnitOffset = StartOffset + 11 /* Header size */; // The root DIE might be null, meaning that the Unit had nothing to @@ -125,100 +403,58 @@ uint64_t CompileUnit::computeNextUnitOffset() { return NextUnitOffset; } -/// \brief Keep track of a forward reference to \p Die. -void CompileUnit::noteForwardReference(DIE *Die, DIEInteger *Attr) { - ForwardDIEReferences.emplace_back(Die, Attr); +/// \brief Keep track of a forward cross-cu reference from this unit +/// to \p Die that lives in \p RefUnit. +void CompileUnit::noteForwardReference(DIE *Die, const CompileUnit *RefUnit, + DeclContext *Ctxt, PatchLocation Attr) { + ForwardDIEReferences.emplace_back(Die, RefUnit, Ctxt, Attr); } /// \brief Apply all fixups recorded by noteForwardReference(). void CompileUnit::fixupForwardReferences() { - for (const auto &Ref : ForwardDIEReferences) - Ref.second->setValue(Ref.first->getOffset() + getStartOffset()); -} - -/// \brief A string table that doesn't need relocations. -/// -/// We are doing a final link, no need for a string table that -/// has relocation entries for every reference to it. This class -/// provides this ablitity by just associating offsets with -/// strings. -class NonRelocatableStringpool { -public: - /// \brief Entries are stored into the StringMap and simply linked - /// together through the second element of this pair in order to - /// keep track of insertion order. - typedef StringMap, BumpPtrAllocator> - MapTy; - - NonRelocatableStringpool() - : CurrentEndOffset(0), Sentinel(0), Last(&Sentinel) { - // Legacy dsymutil puts an empty string at the start of the line - // table. - getStringOffset(""); - } - - /// \brief Get the offset of string \p S in the string table. This - /// can insert a new element or return the offset of a preexisitng - /// one. - uint32_t getStringOffset(StringRef S); - - /// \brief Get permanent storage for \p S (but do not necessarily - /// emit \p S in the output section). - /// \returns The StringRef that points to permanent storage to use - /// in place of \p S. - StringRef internString(StringRef S); - - // \brief Return the first entry of the string table. - const MapTy::MapEntryTy *getFirstEntry() const { - return getNextEntry(&Sentinel); - } - - // \brief Get the entry following \p E in the string table or null - // if \p E was the last entry. - const MapTy::MapEntryTy *getNextEntry(const MapTy::MapEntryTy *E) const { - return static_cast(E->getValue().second); + for (const auto &Ref : ForwardDIEReferences) { + DIE *RefDie; + const CompileUnit *RefUnit; + PatchLocation Attr; + DeclContext *Ctxt; + std::tie(RefDie, RefUnit, Ctxt, Attr) = Ref; + if (Ctxt && Ctxt->getCanonicalDIEOffset()) + Attr.set(Ctxt->getCanonicalDIEOffset()); + else + Attr.set(RefDie->getOffset() + RefUnit->getStartOffset()); } +} - uint64_t getSize() { return CurrentEndOffset; } - -private: - MapTy Strings; - uint32_t CurrentEndOffset; - MapTy::MapEntryTy Sentinel, *Last; -}; +void CompileUnit::addFunctionRange(uint64_t FuncLowPc, uint64_t FuncHighPc, + int64_t PcOffset) { + Ranges.insert(FuncLowPc, FuncHighPc, PcOffset); + this->LowPc = std::min(LowPc, FuncLowPc + PcOffset); + this->HighPc = std::max(HighPc, FuncHighPc + PcOffset); +} -/// \brief Get the offset of string \p S in the string table. This -/// can insert a new element or return the offset of a preexisitng -/// one. -uint32_t NonRelocatableStringpool::getStringOffset(StringRef S) { - if (S.empty() && !Strings.empty()) - return 0; +void CompileUnit::noteRangeAttribute(const DIE &Die, PatchLocation Attr) { + if (Die.getTag() != dwarf::DW_TAG_compile_unit) + RangeAttributes.push_back(Attr); + else + UnitRangeAttribute = Attr; +} - std::pair Entry(0, nullptr); - MapTy::iterator It; - bool Inserted; +void CompileUnit::noteLocationAttribute(PatchLocation Attr, int64_t PcOffset) { + LocationAttributes.emplace_back(Attr, PcOffset); +} - // A non-empty string can't be at offset 0, so if we have an entry - // with a 0 offset, it must be a previously interned string. - std::tie(It, Inserted) = Strings.insert(std::make_pair(S, Entry)); - if (Inserted || It->getValue().first == 0) { - // Set offset and chain at the end of the entries list. - It->getValue().first = CurrentEndOffset; - CurrentEndOffset += S.size() + 1; // +1 for the '\0'. - Last->getValue().second = &*It; - Last = &*It; - } - return It->getValue().first; +/// \brief Add a name accelerator entry for \p Die with \p Name +/// which is stored in the string table at \p Offset. +void CompileUnit::addNameAccelerator(const DIE *Die, const char *Name, + uint32_t Offset, bool SkipPubSection) { + Pubnames.emplace_back(Name, Die, Offset, SkipPubSection); } -/// \brief Put \p S into the StringMap so that it gets permanent -/// storage, but do not actually link it in the chain of elements -/// that go into the output section. A latter call to -/// getStringOffset() with the same string will chain it though. -StringRef NonRelocatableStringpool::internString(StringRef S) { - std::pair Entry(0, nullptr); - auto InsertResult = Strings.insert(std::make_pair(S, Entry)); - return InsertResult.first->getKey(); +/// \brief Add a type accelerator entry for \p Die with \p Name +/// which is stored in the string table at \p Offset. +void CompileUnit::addTypeAccelerator(const DIE *Die, const char *Name, + uint32_t Offset) { + Pubtypes.emplace_back(Name, Die, Offset, false); } /// \brief The Dwarf streaming logic @@ -244,6 +480,17 @@ class DwarfStreamer { /// \brief the file we stream the linked Dwarf to. std::unique_ptr OutFile; + uint32_t RangesSectionSize; + uint32_t LocSectionSize; + uint32_t LineSectionSize; + uint32_t FrameSectionSize; + + /// \brief Emit the pubnames or pubtypes section contribution for \p + /// Unit into \p Sec. The data is provided in \p Names. + void emitPubSectionForUnit(MCSection *Sec, StringRef Name, + const CompileUnit &Unit, + const std::vector &Names); + public: /// \brief Actually create the streamer and the ouptut file. /// @@ -252,7 +499,7 @@ public: bool init(Triple TheTriple, StringRef OutputFilename); /// \brief Dump the file to the disk. - bool finish(); + bool finish(const DebugMap &); AsmPrinter &getAsmPrinter() const { return *Asm; } @@ -272,10 +519,54 @@ public: /// \brief Emit the abbreviation table \p Abbrevs to the /// debug_abbrev section. - void emitAbbrevs(const std::vector &Abbrevs); + void emitAbbrevs(const std::vector> &Abbrevs); /// \brief Emit the string table described by \p Pool. void emitStrings(const NonRelocatableStringpool &Pool); + + /// \brief Emit debug_ranges for \p FuncRange by translating the + /// original \p Entries. + void emitRangesEntries( + int64_t UnitPcOffset, uint64_t OrigLowPc, + FunctionIntervals::const_iterator FuncRange, + const std::vector &Entries, + unsigned AddressSize); + + /// \brief Emit debug_aranges entries for \p Unit and if \p + /// DoRangesSection is true, also emit the debug_ranges entries for + /// the DW_TAG_compile_unit's DW_AT_ranges attribute. + void emitUnitRangesEntries(CompileUnit &Unit, bool DoRangesSection); + + uint32_t getRangesSectionSize() const { return RangesSectionSize; } + + /// \brief Emit the debug_loc contribution for \p Unit by copying + /// the entries from \p Dwarf and offseting them. Update the + /// location attributes to point to the new entries. + void emitLocationsForUnit(const CompileUnit &Unit, DWARFContext &Dwarf); + + /// \brief Emit the line table described in \p Rows into the + /// debug_line section. + void emitLineTableForUnit(MCDwarfLineTableParams Params, + StringRef PrologueBytes, unsigned MinInstLength, + std::vector &Rows, + unsigned AdddressSize); + + uint32_t getLineSectionSize() const { return LineSectionSize; } + + /// \brief Emit the .debug_pubnames contribution for \p Unit. + void emitPubNamesForUnit(const CompileUnit &Unit); + + /// \brief Emit the .debug_pubtypes contribution for \p Unit. + void emitPubTypesForUnit(const CompileUnit &Unit); + + /// \brief Emit a CIE. + void emitCIE(StringRef CIEBytes); + + /// \brief Emit an FDE with data \p Bytes. + void emitFDE(uint32_t CIEOffset, uint32_t AddreSize, uint32_t Address, + StringRef Bytes); + + uint32_t getFrameSectionSize() const { return FrameSectionSize; } }; bool DwarfStreamer::init(Triple TheTriple, StringRef OutputFilename) { @@ -301,7 +592,7 @@ bool DwarfStreamer::init(Triple TheTriple, StringRef OutputFilename) { MOFI.reset(new MCObjectFileInfo); MC.reset(new MCContext(MAI.get(), MRI.get(), MOFI.get())); - MOFI->InitMCObjectFileInfo(TripleName, Reloc::Default, CodeModel::Default, + MOFI->InitMCObjectFileInfo(TheTriple, Reloc::Default, CodeModel::Default, *MC); MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, ""); @@ -316,7 +607,7 @@ bool DwarfStreamer::init(Triple TheTriple, StringRef OutputFilename) { if (!MSTI) return error("no subtarget info for target " + TripleName, Context); - MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, *MSTI, *MC); + MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, *MC); if (!MCE) return error("no code emitter for target " + TripleName, Context); @@ -327,8 +618,9 @@ bool DwarfStreamer::init(Triple TheTriple, StringRef OutputFilename) { if (EC) return error(Twine(OutputFilename) + ": " + EC.message(), Context); - MS = TheTarget->createMCObjectStreamer(TripleName, *MC, *MAB, *OutFile, MCE, - *MSTI, false); + MS = TheTarget->createMCObjectStreamer(TheTriple, *MC, *MAB, *OutFile, MCE, + *MSTI, false, + /*DWARFMustBeAtTheEnd*/ false); if (!MS) return error("no object streamer for target " + TripleName, Context); @@ -341,10 +633,18 @@ bool DwarfStreamer::init(Triple TheTriple, StringRef OutputFilename) { if (!Asm) return error("no asm printer for target " + TripleName, Context); + RangesSectionSize = 0; + LocSectionSize = 0; + LineSectionSize = 0; + FrameSectionSize = 0; + return true; } -bool DwarfStreamer::finish() { +bool DwarfStreamer::finish(const DebugMap &DM) { + if (DM.getTriple().isOSDarwin() && !DM.getBinaryPath().empty()) + return MachOUtils::generateDsymCompanion(DM, *MS, *OutFile); + MS->Finish(); return true; } @@ -383,7 +683,8 @@ void DwarfStreamer::emitCompileUnitHeader(CompileUnit &Unit) { /// \brief Emit the \p Abbrevs array as the shared abbreviation table /// for the linked Dwarf file. -void DwarfStreamer::emitAbbrevs(const std::vector &Abbrevs) { +void DwarfStreamer::emitAbbrevs( + const std::vector> &Abbrevs) { MS->SwitchSection(MOFI->getDwarfAbbrevSection()); Asm->emitDwarfAbbrevs(Abbrevs); } @@ -396,13 +697,401 @@ void DwarfStreamer::emitDIE(DIE &Die) { /// \brief Emit the debug_str section stored in \p Pool. void DwarfStreamer::emitStrings(const NonRelocatableStringpool &Pool) { - Asm->OutStreamer.SwitchSection(MOFI->getDwarfStrSection()); + Asm->OutStreamer->SwitchSection(MOFI->getDwarfStrSection()); for (auto *Entry = Pool.getFirstEntry(); Entry; Entry = Pool.getNextEntry(Entry)) - Asm->OutStreamer.EmitBytes( + Asm->OutStreamer->EmitBytes( StringRef(Entry->getKey().data(), Entry->getKey().size() + 1)); } +/// \brief Emit the debug_range section contents for \p FuncRange by +/// translating the original \p Entries. The debug_range section +/// format is totally trivial, consisting just of pairs of address +/// sized addresses describing the ranges. +void DwarfStreamer::emitRangesEntries( + int64_t UnitPcOffset, uint64_t OrigLowPc, + FunctionIntervals::const_iterator FuncRange, + const std::vector &Entries, + unsigned AddressSize) { + MS->SwitchSection(MC->getObjectFileInfo()->getDwarfRangesSection()); + + // Offset each range by the right amount. + int64_t PcOffset = Entries.empty() ? 0 : FuncRange.value() + UnitPcOffset; + for (const auto &Range : Entries) { + if (Range.isBaseAddressSelectionEntry(AddressSize)) { + warn("unsupported base address selection operation", + "emitting debug_ranges"); + break; + } + // Do not emit empty ranges. + if (Range.StartAddress == Range.EndAddress) + continue; + + // All range entries should lie in the function range. + if (!(Range.StartAddress + OrigLowPc >= FuncRange.start() && + Range.EndAddress + OrigLowPc <= FuncRange.stop())) + warn("inconsistent range data.", "emitting debug_ranges"); + MS->EmitIntValue(Range.StartAddress + PcOffset, AddressSize); + MS->EmitIntValue(Range.EndAddress + PcOffset, AddressSize); + RangesSectionSize += 2 * AddressSize; + } + + // Add the terminator entry. + MS->EmitIntValue(0, AddressSize); + MS->EmitIntValue(0, AddressSize); + RangesSectionSize += 2 * AddressSize; +} + +/// \brief Emit the debug_aranges contribution of a unit and +/// if \p DoDebugRanges is true the debug_range contents for a +/// compile_unit level DW_AT_ranges attribute (Which are basically the +/// same thing with a different base address). +/// Just aggregate all the ranges gathered inside that unit. +void DwarfStreamer::emitUnitRangesEntries(CompileUnit &Unit, + bool DoDebugRanges) { + unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize(); + // Gather the ranges in a vector, so that we can simplify them. The + // IntervalMap will have coalesced the non-linked ranges, but here + // we want to coalesce the linked addresses. + std::vector> Ranges; + const auto &FunctionRanges = Unit.getFunctionRanges(); + for (auto Range = FunctionRanges.begin(), End = FunctionRanges.end(); + Range != End; ++Range) + Ranges.push_back(std::make_pair(Range.start() + Range.value(), + Range.stop() + Range.value())); + + // The object addresses where sorted, but again, the linked + // addresses might end up in a different order. + std::sort(Ranges.begin(), Ranges.end()); + + if (!Ranges.empty()) { + MS->SwitchSection(MC->getObjectFileInfo()->getDwarfARangesSection()); + + MCSymbol *BeginLabel = Asm->createTempSymbol("Barange"); + MCSymbol *EndLabel = Asm->createTempSymbol("Earange"); + + unsigned HeaderSize = + sizeof(int32_t) + // Size of contents (w/o this field + sizeof(int16_t) + // DWARF ARange version number + sizeof(int32_t) + // Offset of CU in the .debug_info section + sizeof(int8_t) + // Pointer Size (in bytes) + sizeof(int8_t); // Segment Size (in bytes) + + unsigned TupleSize = AddressSize * 2; + unsigned Padding = OffsetToAlignment(HeaderSize, TupleSize); + + Asm->EmitLabelDifference(EndLabel, BeginLabel, 4); // Arange length + Asm->OutStreamer->EmitLabel(BeginLabel); + Asm->EmitInt16(dwarf::DW_ARANGES_VERSION); // Version number + Asm->EmitInt32(Unit.getStartOffset()); // Corresponding unit's offset + Asm->EmitInt8(AddressSize); // Address size + Asm->EmitInt8(0); // Segment size + + Asm->OutStreamer->EmitFill(Padding, 0x0); + + for (auto Range = Ranges.begin(), End = Ranges.end(); Range != End; + ++Range) { + uint64_t RangeStart = Range->first; + MS->EmitIntValue(RangeStart, AddressSize); + while ((Range + 1) != End && Range->second == (Range + 1)->first) + ++Range; + MS->EmitIntValue(Range->second - RangeStart, AddressSize); + } + + // Emit terminator + Asm->OutStreamer->EmitIntValue(0, AddressSize); + Asm->OutStreamer->EmitIntValue(0, AddressSize); + Asm->OutStreamer->EmitLabel(EndLabel); + } + + if (!DoDebugRanges) + return; + + MS->SwitchSection(MC->getObjectFileInfo()->getDwarfRangesSection()); + // Offset each range by the right amount. + int64_t PcOffset = -Unit.getLowPc(); + // Emit coalesced ranges. + for (auto Range = Ranges.begin(), End = Ranges.end(); Range != End; ++Range) { + MS->EmitIntValue(Range->first + PcOffset, AddressSize); + while (Range + 1 != End && Range->second == (Range + 1)->first) + ++Range; + MS->EmitIntValue(Range->second + PcOffset, AddressSize); + RangesSectionSize += 2 * AddressSize; + } + + // Add the terminator entry. + MS->EmitIntValue(0, AddressSize); + MS->EmitIntValue(0, AddressSize); + RangesSectionSize += 2 * AddressSize; +} + +/// \brief Emit location lists for \p Unit and update attribtues to +/// point to the new entries. +void DwarfStreamer::emitLocationsForUnit(const CompileUnit &Unit, + DWARFContext &Dwarf) { + const auto &Attributes = Unit.getLocationAttributes(); + + if (Attributes.empty()) + return; + + MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLocSection()); + + unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize(); + const DWARFSection &InputSec = Dwarf.getLocSection(); + DataExtractor Data(InputSec.Data, Dwarf.isLittleEndian(), AddressSize); + DWARFUnit &OrigUnit = Unit.getOrigUnit(); + const auto *OrigUnitDie = OrigUnit.getUnitDIE(false); + int64_t UnitPcOffset = 0; + uint64_t OrigLowPc = OrigUnitDie->getAttributeValueAsAddress( + &OrigUnit, dwarf::DW_AT_low_pc, -1ULL); + if (OrigLowPc != -1ULL) + UnitPcOffset = int64_t(OrigLowPc) - Unit.getLowPc(); + + for (const auto &Attr : Attributes) { + uint32_t Offset = Attr.first.get(); + Attr.first.set(LocSectionSize); + // This is the quantity to add to the old location address to get + // the correct address for the new one. + int64_t LocPcOffset = Attr.second + UnitPcOffset; + while (Data.isValidOffset(Offset)) { + uint64_t Low = Data.getUnsigned(&Offset, AddressSize); + uint64_t High = Data.getUnsigned(&Offset, AddressSize); + LocSectionSize += 2 * AddressSize; + if (Low == 0 && High == 0) { + Asm->OutStreamer->EmitIntValue(0, AddressSize); + Asm->OutStreamer->EmitIntValue(0, AddressSize); + break; + } + Asm->OutStreamer->EmitIntValue(Low + LocPcOffset, AddressSize); + Asm->OutStreamer->EmitIntValue(High + LocPcOffset, AddressSize); + uint64_t Length = Data.getU16(&Offset); + Asm->OutStreamer->EmitIntValue(Length, 2); + // Just copy the bytes over. + Asm->OutStreamer->EmitBytes( + StringRef(InputSec.Data.substr(Offset, Length))); + Offset += Length; + LocSectionSize += Length + 2; + } + } +} + +void DwarfStreamer::emitLineTableForUnit(MCDwarfLineTableParams Params, + StringRef PrologueBytes, + unsigned MinInstLength, + std::vector &Rows, + unsigned PointerSize) { + // Switch to the section where the table will be emitted into. + MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLineSection()); + MCSymbol *LineStartSym = MC->createTempSymbol(); + MCSymbol *LineEndSym = MC->createTempSymbol(); + + // The first 4 bytes is the total length of the information for this + // compilation unit (not including these 4 bytes for the length). + Asm->EmitLabelDifference(LineEndSym, LineStartSym, 4); + Asm->OutStreamer->EmitLabel(LineStartSym); + // Copy Prologue. + MS->EmitBytes(PrologueBytes); + LineSectionSize += PrologueBytes.size() + 4; + + SmallString<128> EncodingBuffer; + raw_svector_ostream EncodingOS(EncodingBuffer); + + if (Rows.empty()) { + // We only have the dummy entry, dsymutil emits an entry with a 0 + // address in that case. + MCDwarfLineAddr::Encode(*MC, Params, INT64_MAX, 0, EncodingOS); + MS->EmitBytes(EncodingOS.str()); + LineSectionSize += EncodingBuffer.size(); + MS->EmitLabel(LineEndSym); + return; + } + + // Line table state machine fields + unsigned FileNum = 1; + unsigned LastLine = 1; + unsigned Column = 0; + unsigned IsStatement = 1; + unsigned Isa = 0; + uint64_t Address = -1ULL; + + unsigned RowsSinceLastSequence = 0; + + for (unsigned Idx = 0; Idx < Rows.size(); ++Idx) { + auto &Row = Rows[Idx]; + + int64_t AddressDelta; + if (Address == -1ULL) { + MS->EmitIntValue(dwarf::DW_LNS_extended_op, 1); + MS->EmitULEB128IntValue(PointerSize + 1); + MS->EmitIntValue(dwarf::DW_LNE_set_address, 1); + MS->EmitIntValue(Row.Address, PointerSize); + LineSectionSize += 2 + PointerSize + getULEB128Size(PointerSize + 1); + AddressDelta = 0; + } else { + AddressDelta = (Row.Address - Address) / MinInstLength; + } + + // FIXME: code copied and transfromed from + // MCDwarf.cpp::EmitDwarfLineTable. We should find a way to share + // this code, but the current compatibility requirement with + // classic dsymutil makes it hard. Revisit that once this + // requirement is dropped. + + if (FileNum != Row.File) { + FileNum = Row.File; + MS->EmitIntValue(dwarf::DW_LNS_set_file, 1); + MS->EmitULEB128IntValue(FileNum); + LineSectionSize += 1 + getULEB128Size(FileNum); + } + if (Column != Row.Column) { + Column = Row.Column; + MS->EmitIntValue(dwarf::DW_LNS_set_column, 1); + MS->EmitULEB128IntValue(Column); + LineSectionSize += 1 + getULEB128Size(Column); + } + + // FIXME: We should handle the discriminator here, but dsymutil + // doesn' consider it, thus ignore it for now. + + if (Isa != Row.Isa) { + Isa = Row.Isa; + MS->EmitIntValue(dwarf::DW_LNS_set_isa, 1); + MS->EmitULEB128IntValue(Isa); + LineSectionSize += 1 + getULEB128Size(Isa); + } + if (IsStatement != Row.IsStmt) { + IsStatement = Row.IsStmt; + MS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1); + LineSectionSize += 1; + } + if (Row.BasicBlock) { + MS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1); + LineSectionSize += 1; + } + + if (Row.PrologueEnd) { + MS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1); + LineSectionSize += 1; + } + + if (Row.EpilogueBegin) { + MS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1); + LineSectionSize += 1; + } + + int64_t LineDelta = int64_t(Row.Line) - LastLine; + if (!Row.EndSequence) { + MCDwarfLineAddr::Encode(*MC, Params, LineDelta, AddressDelta, EncodingOS); + MS->EmitBytes(EncodingOS.str()); + LineSectionSize += EncodingBuffer.size(); + EncodingBuffer.resize(0); + Address = Row.Address; + LastLine = Row.Line; + RowsSinceLastSequence++; + } else { + if (LineDelta) { + MS->EmitIntValue(dwarf::DW_LNS_advance_line, 1); + MS->EmitSLEB128IntValue(LineDelta); + LineSectionSize += 1 + getSLEB128Size(LineDelta); + } + if (AddressDelta) { + MS->EmitIntValue(dwarf::DW_LNS_advance_pc, 1); + MS->EmitULEB128IntValue(AddressDelta); + LineSectionSize += 1 + getULEB128Size(AddressDelta); + } + MCDwarfLineAddr::Encode(*MC, Params, INT64_MAX, 0, EncodingOS); + MS->EmitBytes(EncodingOS.str()); + LineSectionSize += EncodingBuffer.size(); + EncodingBuffer.resize(0); + Address = -1ULL; + LastLine = FileNum = IsStatement = 1; + RowsSinceLastSequence = Column = Isa = 0; + } + } + + if (RowsSinceLastSequence) { + MCDwarfLineAddr::Encode(*MC, Params, INT64_MAX, 0, EncodingOS); + MS->EmitBytes(EncodingOS.str()); + LineSectionSize += EncodingBuffer.size(); + EncodingBuffer.resize(0); + } + + MS->EmitLabel(LineEndSym); +} + +/// \brief Emit the pubnames or pubtypes section contribution for \p +/// Unit into \p Sec. The data is provided in \p Names. +void DwarfStreamer::emitPubSectionForUnit( + MCSection *Sec, StringRef SecName, const CompileUnit &Unit, + const std::vector &Names) { + if (Names.empty()) + return; + + // Start the dwarf pubnames section. + Asm->OutStreamer->SwitchSection(Sec); + MCSymbol *BeginLabel = Asm->createTempSymbol("pub" + SecName + "_begin"); + MCSymbol *EndLabel = Asm->createTempSymbol("pub" + SecName + "_end"); + + bool HeaderEmitted = false; + // Emit the pubnames for this compilation unit. + for (const auto &Name : Names) { + if (Name.SkipPubSection) + continue; + + if (!HeaderEmitted) { + // Emit the header. + Asm->EmitLabelDifference(EndLabel, BeginLabel, 4); // Length + Asm->OutStreamer->EmitLabel(BeginLabel); + Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION); // Version + Asm->EmitInt32(Unit.getStartOffset()); // Unit offset + Asm->EmitInt32(Unit.getNextUnitOffset() - Unit.getStartOffset()); // Size + HeaderEmitted = true; + } + Asm->EmitInt32(Name.Die->getOffset()); + Asm->OutStreamer->EmitBytes( + StringRef(Name.Name.data(), Name.Name.size() + 1)); + } + + if (!HeaderEmitted) + return; + Asm->EmitInt32(0); // End marker. + Asm->OutStreamer->EmitLabel(EndLabel); +} + +/// \brief Emit .debug_pubnames for \p Unit. +void DwarfStreamer::emitPubNamesForUnit(const CompileUnit &Unit) { + emitPubSectionForUnit(MC->getObjectFileInfo()->getDwarfPubNamesSection(), + "names", Unit, Unit.getPubnames()); +} + +/// \brief Emit .debug_pubtypes for \p Unit. +void DwarfStreamer::emitPubTypesForUnit(const CompileUnit &Unit) { + emitPubSectionForUnit(MC->getObjectFileInfo()->getDwarfPubTypesSection(), + "types", Unit, Unit.getPubtypes()); +} + +/// \brief Emit a CIE into the debug_frame section. +void DwarfStreamer::emitCIE(StringRef CIEBytes) { + MS->SwitchSection(MC->getObjectFileInfo()->getDwarfFrameSection()); + + MS->EmitBytes(CIEBytes); + FrameSectionSize += CIEBytes.size(); +} + +/// \brief Emit a FDE into the debug_frame section. \p FDEBytes +/// contains the FDE data without the length, CIE offset and address +/// which will be replaced with the paramter values. +void DwarfStreamer::emitFDE(uint32_t CIEOffset, uint32_t AddrSize, + uint32_t Address, StringRef FDEBytes) { + MS->SwitchSection(MC->getObjectFileInfo()->getDwarfFrameSection()); + + MS->EmitIntValue(FDEBytes.size() + 4 + AddrSize, 4); + MS->EmitIntValue(CIEOffset, 4); + MS->EmitIntValue(Address, AddrSize); + MS->EmitBytes(FDEBytes); + FrameSectionSize += FDEBytes.size() + 8 + AddrSize; +} + /// \brief The core of the Dwarf linking logic. /// /// The link of the dwarf information from the object files will be @@ -421,96 +1110,139 @@ class DwarfLinker { public: DwarfLinker(StringRef OutputFilename, const LinkOptions &Options) : OutputFilename(OutputFilename), Options(Options), - BinHolder(Options.Verbose) {} - - ~DwarfLinker() { - for (auto *Abbrev : Abbreviations) - delete Abbrev; - } + BinHolder(Options.Verbose), LastCIEOffset(0) {} /// \brief Link the contents of the DebugMap. bool link(const DebugMap &); + void reportWarning(const Twine &Warning, const DWARFUnit *Unit = nullptr, + const DWARFDebugInfoEntryMinimal *DIE = nullptr) const; + private: /// \brief Called at the start of a debug object link. - void startDebugObject(DWARFContext &); + void startDebugObject(DWARFContext &, DebugMapObject &); /// \brief Called at the end of a debug object link. void endDebugObject(); - /// \defgroup FindValidRelocations Translate debug map into a list - /// of relevant relocations - /// - /// @{ - struct ValidReloc { - uint32_t Offset; - uint32_t Size; - uint64_t Addend; - const DebugMapObject::DebugMapEntry *Mapping; + /// Keeps track of relocations. + class RelocationManager { + struct ValidReloc { + uint32_t Offset; + uint32_t Size; + uint64_t Addend; + const DebugMapObject::DebugMapEntry *Mapping; - ValidReloc(uint32_t Offset, uint32_t Size, uint64_t Addend, - const DebugMapObject::DebugMapEntry *Mapping) - : Offset(Offset), Size(Size), Addend(Addend), Mapping(Mapping) {} + ValidReloc(uint32_t Offset, uint32_t Size, uint64_t Addend, + const DebugMapObject::DebugMapEntry *Mapping) + : Offset(Offset), Size(Size), Addend(Addend), Mapping(Mapping) {} - bool operator<(const ValidReloc &RHS) const { return Offset < RHS.Offset; } + bool operator<(const ValidReloc &RHS) const { + return Offset < RHS.Offset; + } + }; + + DwarfLinker &Linker; + + /// \brief The valid relocations for the current DebugMapObject. + /// This vector is sorted by relocation offset. + std::vector ValidRelocs; + + /// \brief Index into ValidRelocs of the next relocation to + /// consider. As we walk the DIEs in acsending file offset and as + /// ValidRelocs is sorted by file offset, keeping this index + /// uptodate is all we have to do to have a cheap lookup during the + /// root DIE selection and during DIE cloning. + unsigned NextValidReloc; + + public: + RelocationManager(DwarfLinker &Linker) + : Linker(Linker), NextValidReloc(0) {} + + bool hasValidRelocs() const { return !ValidRelocs.empty(); } + /// \brief Reset the NextValidReloc counter. + void resetValidRelocs() { NextValidReloc = 0; } + + /// \defgroup FindValidRelocations Translate debug map into a list + /// of relevant relocations + /// + /// @{ + bool findValidRelocsInDebugInfo(const object::ObjectFile &Obj, + const DebugMapObject &DMO); + + bool findValidRelocs(const object::SectionRef &Section, + const object::ObjectFile &Obj, + const DebugMapObject &DMO); + + void findValidRelocsMachO(const object::SectionRef &Section, + const object::MachOObjectFile &Obj, + const DebugMapObject &DMO); + /// @} + + bool hasValidRelocation(uint32_t StartOffset, uint32_t EndOffset, + CompileUnit::DIEInfo &Info); + + bool applyValidRelocs(MutableArrayRef Data, uint32_t BaseOffset, + bool isLittleEndian); }; - /// \brief The valid relocations for the current DebugMapObject. - /// This vector is sorted by relocation offset. - std::vector ValidRelocs; - - /// \brief Index into ValidRelocs of the next relocation to - /// consider. As we walk the DIEs in acsending file offset and as - /// ValidRelocs is sorted by file offset, keeping this index - /// uptodate is all we have to do to have a cheap lookup during the - /// root DIE selection and during DIE cloning. - unsigned NextValidReloc; - - bool findValidRelocsInDebugInfo(const object::ObjectFile &Obj, - const DebugMapObject &DMO); - - bool findValidRelocs(const object::SectionRef &Section, - const object::ObjectFile &Obj, - const DebugMapObject &DMO); - - void findValidRelocsMachO(const object::SectionRef &Section, - const object::MachOObjectFile &Obj, - const DebugMapObject &DMO); - /// @} - /// \defgroup FindRootDIEs Find DIEs corresponding to debug map entries. /// /// @{ /// \brief Recursively walk the \p DIE tree and look for DIEs to /// keep. Store that information in \p CU's DIEInfo. - void lookForDIEsToKeep(const DWARFDebugInfoEntryMinimal &DIE, + void lookForDIEsToKeep(RelocationManager &RelocMgr, + const DWARFDebugInfoEntryMinimal &DIE, const DebugMapObject &DMO, CompileUnit &CU, unsigned Flags); + /// If this compile unit is really a skeleton CU that points to a + /// clang module, register it in ClangModules and return true. + /// + /// A skeleton CU is a CU without children, a DW_AT_gnu_dwo_name + /// pointing to the module, and a DW_AT_gnu_dwo_id with the module + /// hash. + bool registerModuleReference(const DWARFDebugInfoEntryMinimal &CUDie, + const DWARFUnit &Unit, DebugMap &ModuleMap, + unsigned Indent = 0); + + /// Recursively add the debug info in this clang module .pcm + /// file (and all the modules imported by it in a bottom-up fashion) + /// to Units. + void loadClangModule(StringRef Filename, StringRef ModulePath, + StringRef ModuleName, uint64_t DwoId, + DebugMap &ModuleMap, unsigned Indent = 0); + /// \brief Flags passed to DwarfLinker::lookForDIEsToKeep enum TravesalFlags { TF_Keep = 1 << 0, ///< Mark the traversed DIEs as kept. TF_InFunctionScope = 1 << 1, ///< Current scope is a fucntion scope. TF_DependencyWalk = 1 << 2, ///< Walking the dependencies of a kept DIE. TF_ParentWalk = 1 << 3, ///< Walking up the parents of a kept DIE. + TF_ODR = 1 << 4, ///< Use the ODR whhile keeping dependants. + TF_SkipPC = 1 << 5, ///< Skip all location attributes. }; /// \brief Mark the passed DIE as well as all the ones it depends on /// as kept. - void keepDIEAndDenpendencies(const DWARFDebugInfoEntryMinimal &DIE, + void keepDIEAndDependencies(RelocationManager &RelocMgr, + const DWARFDebugInfoEntryMinimal &DIE, CompileUnit::DIEInfo &MyInfo, const DebugMapObject &DMO, CompileUnit &CU, - unsigned Flags); + bool UseODR); - unsigned shouldKeepDIE(const DWARFDebugInfoEntryMinimal &DIE, + unsigned shouldKeepDIE(RelocationManager &RelocMgr, + const DWARFDebugInfoEntryMinimal &DIE, CompileUnit &Unit, CompileUnit::DIEInfo &MyInfo, unsigned Flags); - unsigned shouldKeepVariableDIE(const DWARFDebugInfoEntryMinimal &DIE, + unsigned shouldKeepVariableDIE(RelocationManager &RelocMgr, + const DWARFDebugInfoEntryMinimal &DIE, CompileUnit &Unit, CompileUnit::DIEInfo &MyInfo, unsigned Flags); - unsigned shouldKeepSubprogramDIE(const DWARFDebugInfoEntryMinimal &DIE, + unsigned shouldKeepSubprogramDIE(RelocationManager &RelocMgr, + const DWARFDebugInfoEntryMinimal &DIE, CompileUnit &Unit, CompileUnit::DIEInfo &MyInfo, unsigned Flags); @@ -522,49 +1254,118 @@ private: /// \defgroup Linking Methods used to link the debug information /// /// @{ - /// \brief Recursively clone \p InputDIE into an tree of DIE objects - /// where useless (as decided by lookForDIEsToKeep()) bits have been - /// stripped out and addresses have been rewritten according to the - /// debug map. - /// - /// \param OutOffset is the offset the cloned DIE in the output - /// compile unit. - /// - /// \returns the root of the cloned tree. - DIE *cloneDIE(const DWARFDebugInfoEntryMinimal &InputDIE, CompileUnit &U, - uint32_t OutOffset); - - typedef DWARFAbbreviationDeclaration::AttributeSpec AttributeSpec; - - /// \brief Helper for cloneDIE. - unsigned cloneAttribute(DIE &Die, const DWARFDebugInfoEntryMinimal &InputDIE, - CompileUnit &U, const DWARFFormValue &Val, - const AttributeSpec AttrSpec, unsigned AttrSize); - - /// \brief Helper for cloneDIE. - unsigned cloneStringAttribute(DIE &Die, AttributeSpec AttrSpec, - const DWARFFormValue &Val, const DWARFUnit &U); - - /// \brief Helper for cloneDIE. - unsigned - cloneDieReferenceAttribute(DIE &Die, - const DWARFDebugInfoEntryMinimal &InputDIE, - AttributeSpec AttrSpec, unsigned AttrSize, - const DWARFFormValue &Val, const DWARFUnit &U); - - /// \brief Helper for cloneDIE. - unsigned cloneBlockAttribute(DIE &Die, AttributeSpec AttrSpec, - const DWARFFormValue &Val, unsigned AttrSize); - - /// \brief Helper for cloneDIE. - unsigned cloneScalarAttribute(DIE &Die, - const DWARFDebugInfoEntryMinimal &InputDIE, - const DWARFUnit &U, AttributeSpec AttrSpec, - const DWARFFormValue &Val, unsigned AttrSize); - - /// \brief Helper for cloneDIE. - bool applyValidRelocs(MutableArrayRef Data, uint32_t BaseOffset, - bool isLittleEndian); + + class DIECloner { + DwarfLinker &Linker; + RelocationManager &RelocMgr; + /// Allocator used for all the DIEValue objects. + BumpPtrAllocator &DIEAlloc; + MutableArrayRef CompileUnits; + LinkOptions Options; + + public: + DIECloner(DwarfLinker &Linker, RelocationManager &RelocMgr, + BumpPtrAllocator &DIEAlloc, + MutableArrayRef CompileUnits, LinkOptions &Options) + : Linker(Linker), RelocMgr(RelocMgr), DIEAlloc(DIEAlloc), + CompileUnits(CompileUnits), Options(Options) {} + + /// Recursively clone \p InputDIE into an tree of DIE objects + /// where useless (as decided by lookForDIEsToKeep()) bits have been + /// stripped out and addresses have been rewritten according to the + /// debug map. + /// + /// \param OutOffset is the offset the cloned DIE in the output + /// compile unit. + /// \param PCOffset (while cloning a function scope) is the offset + /// applied to the entry point of the function to get the linked address. + /// + /// \returns the root of the cloned tree or null if nothing was selected. + DIE *cloneDIE(const DWARFDebugInfoEntryMinimal &InputDIE, CompileUnit &U, + int64_t PCOffset, uint32_t OutOffset, unsigned Flags); + + /// Construct the output DIE tree by cloning the DIEs we + /// chose to keep above. If there are no valid relocs, then there's + /// nothing to clone/emit. + void cloneAllCompileUnits(DWARFContextInMemory &DwarfContext); + + private: + typedef DWARFAbbreviationDeclaration::AttributeSpec AttributeSpec; + + /// Information gathered and exchanged between the various + /// clone*Attributes helpers about the attributes of a particular DIE. + struct AttributesInfo { + const char *Name, *MangledName; ///< Names. + uint32_t NameOffset, MangledNameOffset; ///< Offsets in the string pool. + + uint64_t OrigLowPc; ///< Value of AT_low_pc in the input DIE + uint64_t OrigHighPc; ///< Value of AT_high_pc in the input DIE + int64_t PCOffset; ///< Offset to apply to PC addresses inside a function. + + bool HasLowPc; ///< Does the DIE have a low_pc attribute? + bool IsDeclaration; ///< Is this DIE only a declaration? + + AttributesInfo() + : Name(nullptr), MangledName(nullptr), NameOffset(0), + MangledNameOffset(0), OrigLowPc(UINT64_MAX), OrigHighPc(0), + PCOffset(0), HasLowPc(false), IsDeclaration(false) {} + }; + + /// Helper for cloneDIE. + unsigned cloneAttribute(DIE &Die, + const DWARFDebugInfoEntryMinimal &InputDIE, + CompileUnit &U, const DWARFFormValue &Val, + const AttributeSpec AttrSpec, unsigned AttrSize, + AttributesInfo &AttrInfo); + + /// Clone a string attribute described by \p AttrSpec and add + /// it to \p Die. + /// \returns the size of the new attribute. + unsigned cloneStringAttribute(DIE &Die, AttributeSpec AttrSpec, + const DWARFFormValue &Val, + const DWARFUnit &U); + + /// Clone an attribute referencing another DIE and add + /// it to \p Die. + /// \returns the size of the new attribute. + unsigned + cloneDieReferenceAttribute(DIE &Die, + const DWARFDebugInfoEntryMinimal &InputDIE, + AttributeSpec AttrSpec, unsigned AttrSize, + const DWARFFormValue &Val, CompileUnit &Unit); + + /// Clone an attribute referencing another DIE and add + /// it to \p Die. + /// \returns the size of the new attribute. + unsigned cloneBlockAttribute(DIE &Die, AttributeSpec AttrSpec, + const DWARFFormValue &Val, unsigned AttrSize); + + /// Clone an attribute referencing another DIE and add + /// it to \p Die. + /// \returns the size of the new attribute. + unsigned cloneAddressAttribute(DIE &Die, AttributeSpec AttrSpec, + const DWARFFormValue &Val, + const CompileUnit &Unit, + AttributesInfo &Info); + + /// Clone a scalar attribute and add it to \p Die. + /// \returns the size of the new attribute. + unsigned cloneScalarAttribute(DIE &Die, + const DWARFDebugInfoEntryMinimal &InputDIE, + CompileUnit &U, AttributeSpec AttrSpec, + const DWARFFormValue &Val, unsigned AttrSize, + AttributesInfo &Info); + + /// Get the potential name and mangled name for the entity + /// described by \p Die and store them in \Info if they are not + /// already there. + /// \returns is a name was found. + bool getDIENames(const DWARFDebugInfoEntryMinimal &Die, DWARFUnit &U, + AttributesInfo &Info); + + /// Create a copy of abbreviation Abbrev. + void copyAbbrev(const DWARFAbbreviationDeclaration &Abbrev, bool hasODR); + }; /// \brief Assign an abbreviation number to \p Abbrev void AssignAbbrev(DIEAbbrev &Abbrev); @@ -574,7 +1375,27 @@ private: /// \brief Storage for the unique Abbreviations. /// This is passed to AsmPrinter::emitDwarfAbbrevs(), thus it cannot /// be changed to a vecot of unique_ptrs. - std::vector Abbreviations; + std::vector> Abbreviations; + + /// \brief Compute and emit debug_ranges section for \p Unit, and + /// patch the attributes referencing it. + void patchRangesForUnit(const CompileUnit &Unit, DWARFContext &Dwarf) const; + + /// \brief Generate and emit the DW_AT_ranges attribute for a + /// compile_unit if it had one. + void generateUnitRanges(CompileUnit &Unit) const; + + /// \brief Extract the line tables fromt he original dwarf, extract + /// the relevant parts according to the linked function ranges and + /// emit the result in the debug_line section. + void patchLineTableForUnit(CompileUnit &Unit, DWARFContext &OrigDwarf); + + /// \brief Emit the accelerator entries for \p Unit. + void emitAcceleratorEntriesForUnit(CompileUnit &Unit); + + /// \brief Patch the frame info for an object file and emit it. + void patchFrameInfoForObject(const DebugMapObject &, DWARFContext &, + unsigned AddressSize); /// \brief DIELoc objects that need to be destructed (but not freed!). std::vector DIELocs; @@ -584,71 +1405,323 @@ private: BumpPtrAllocator DIEAlloc; /// @} + /// ODR Contexts for that link. + DeclContextTree ODRContexts; + /// \defgroup Helpers Various helper methods. /// /// @{ - const DWARFDebugInfoEntryMinimal * - resolveDIEReference(DWARFFormValue &RefValue, const DWARFUnit &Unit, - const DWARFDebugInfoEntryMinimal &DIE, - CompileUnit *&ReferencedCU); - - CompileUnit *getUnitForOffset(unsigned Offset); - - void reportWarning(const Twine &Warning, const DWARFUnit *Unit = nullptr, - const DWARFDebugInfoEntryMinimal *DIE = nullptr); - bool createStreamer(Triple TheTriple, StringRef OutputFilename); + + /// \brief Attempt to load a debug object from disk. + ErrorOr loadObject(BinaryHolder &BinaryHolder, + DebugMapObject &Obj, + const DebugMap &Map); /// @} -private: std::string OutputFilename; LinkOptions Options; BinaryHolder BinHolder; std::unique_ptr Streamer; + uint64_t OutputDebugInfoSize; + unsigned UnitID; ///< A unique ID that identifies each compile unit. /// The units of the current debug map object. std::vector Units; - /// The debug map object curently under consideration. + /// The debug map object currently under consideration. DebugMapObject *CurrentDebugObject; /// \brief The Dwarf string pool NonRelocatableStringpool StringPool; + + /// \brief This map is keyed by the entry PC of functions in that + /// debug object and the associated value is a pair storing the + /// corresponding end PC and the offset to apply to get the linked + /// address. + /// + /// See startDebugObject() for a more complete description of its use. + std::map> Ranges; + + /// \brief The CIEs that have been emitted in the output + /// section. The actual CIE data serves a the key to this StringMap, + /// this takes care of comparing the semantics of CIEs defined in + /// different object files. + StringMap EmittedCIEs; + + /// Offset of the last CIE that has been emitted in the output + /// debug_frame section. + uint32_t LastCIEOffset; + + /// Mapping the PCM filename to the DwoId. + StringMap ClangModules; }; -/// \brief Similar to DWARFUnitSection::getUnitForOffset(), but -/// returning our CompileUnit object instead. -CompileUnit *DwarfLinker::getUnitForOffset(unsigned Offset) { - auto CU = - std::upper_bound(Units.begin(), Units.end(), Offset, - [](uint32_t LHS, const CompileUnit &RHS) { - return LHS < RHS.getOrigUnit().getNextUnitOffset(); - }); - return CU != Units.end() ? &*CU : nullptr; +/// Similar to DWARFUnitSection::getUnitForOffset(), but returning our +/// CompileUnit object instead. +static CompileUnit *getUnitForOffset(MutableArrayRef Units, + unsigned Offset) { + auto CU = + std::upper_bound(Units.begin(), Units.end(), Offset, + [](uint32_t LHS, const CompileUnit &RHS) { + return LHS < RHS.getOrigUnit().getNextUnitOffset(); + }); + return CU != Units.end() ? &*CU : nullptr; +} + +/// Resolve the DIE attribute reference that has been +/// extracted in \p RefValue. The resulting DIE migh be in another +/// CompileUnit which is stored into \p ReferencedCU. +/// \returns null if resolving fails for any reason. +static const DWARFDebugInfoEntryMinimal *resolveDIEReference( + const DwarfLinker &Linker, MutableArrayRef Units, + const DWARFFormValue &RefValue, const DWARFUnit &Unit, + const DWARFDebugInfoEntryMinimal &DIE, CompileUnit *&RefCU) { + assert(RefValue.isFormClass(DWARFFormValue::FC_Reference)); + uint64_t RefOffset = *RefValue.getAsReference(&Unit); + + if ((RefCU = getUnitForOffset(Units, RefOffset))) + if (const auto *RefDie = RefCU->getOrigUnit().getDIEForOffset(RefOffset)) + return RefDie; + + Linker.reportWarning("could not find referenced DIE", &Unit, &DIE); + return nullptr; +} + +/// \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."); +} + +/// Set the last DIE/CU a context was seen in and, possibly invalidate +/// the context if it is ambiguous. +/// +/// In the current implementation, we don't handle overloaded +/// functions well, because the argument types are not taken into +/// account when computing the DeclContext tree. +/// +/// Some of this is mitigated byt using mangled names that do contain +/// the arguments types, but sometimes (eg. with function templates) +/// we don't have that. In that case, just do not unique anything that +/// refers to the contexts we are not able to distinguish. +/// +/// If a context that is not a namespace appears twice in the same CU, +/// we know it is ambiguous. Make it invalid. +bool DeclContext::setLastSeenDIE(CompileUnit &U, + const DWARFDebugInfoEntryMinimal *Die) { + if (LastSeenCompileUnitID == U.getUniqueID()) { + DWARFUnit &OrigUnit = U.getOrigUnit(); + uint32_t FirstIdx = OrigUnit.getDIEIndex(LastSeenDIE); + U.getInfo(FirstIdx).Ctxt = nullptr; + return false; + } + + LastSeenCompileUnitID = U.getUniqueID(); + LastSeenDIE = Die; + return true; +} + +PointerIntPair DeclContextTree::getChildDeclContext( + DeclContext &Context, const DWARFDebugInfoEntryMinimal *DIE, CompileUnit &U, + NonRelocatableStringpool &StringPool, bool InClangModule) { + unsigned Tag = DIE->getTag(); + + // FIXME: dsymutil-classic compat: We should bail out here if we + // have a specification or an abstract_origin. We will get the + // parent context wrong here. + + switch (Tag) { + default: + // By default stop gathering child contexts. + return PointerIntPair(nullptr); + case dwarf::DW_TAG_module: + break; + case dwarf::DW_TAG_compile_unit: + return PointerIntPair(&Context); + case dwarf::DW_TAG_subprogram: + // Do not unique anything inside CU local functions. + if ((Context.getTag() == dwarf::DW_TAG_namespace || + Context.getTag() == dwarf::DW_TAG_compile_unit) && + !DIE->getAttributeValueAsUnsignedConstant(&U.getOrigUnit(), + dwarf::DW_AT_external, 0)) + return PointerIntPair(nullptr); + // Fallthrough + case dwarf::DW_TAG_member: + case dwarf::DW_TAG_namespace: + case dwarf::DW_TAG_structure_type: + case dwarf::DW_TAG_class_type: + case dwarf::DW_TAG_union_type: + case dwarf::DW_TAG_enumeration_type: + case dwarf::DW_TAG_typedef: + // Artificial things might be ambiguous, because they might be + // created on demand. For example implicitely defined constructors + // are ambiguous because of the way we identify contexts, and they + // won't be generated everytime everywhere. + if (DIE->getAttributeValueAsUnsignedConstant(&U.getOrigUnit(), + dwarf::DW_AT_artificial, 0)) + return PointerIntPair(nullptr); + break; + } + + const char *Name = DIE->getName(&U.getOrigUnit(), DINameKind::LinkageName); + const char *ShortName = DIE->getName(&U.getOrigUnit(), DINameKind::ShortName); + StringRef NameRef; + StringRef ShortNameRef; + StringRef FileRef; + + if (Name) + NameRef = StringPool.internString(Name); + else if (Tag == dwarf::DW_TAG_namespace) + // FIXME: For dsymutil-classic compatibility. I think uniquing + // within anonymous namespaces is wrong. There is no ODR guarantee + // there. + NameRef = StringPool.internString("(anonymous namespace)"); + + if (ShortName && ShortName != Name) + ShortNameRef = StringPool.internString(ShortName); + else + ShortNameRef = NameRef; + + if (Tag != dwarf::DW_TAG_class_type && Tag != dwarf::DW_TAG_structure_type && + Tag != dwarf::DW_TAG_union_type && + Tag != dwarf::DW_TAG_enumeration_type && NameRef.empty()) + return PointerIntPair(nullptr); + + std::string File; + unsigned Line = 0; + unsigned ByteSize = UINT32_MAX; + + if (!InClangModule) { + // Gather some discriminating data about the DeclContext we will be + // creating: File, line number and byte size. This shouldn't be + // necessary, because the ODR is just about names, but given that we + // do some approximations with overloaded functions and anonymous + // namespaces, use these additional data points to make the process + // safer. This is disabled for clang modules, because forward + // declarations of module-defined types do not have a file and line. + ByteSize = DIE->getAttributeValueAsUnsignedConstant( + &U.getOrigUnit(), dwarf::DW_AT_byte_size, UINT64_MAX); + if (Tag != dwarf::DW_TAG_namespace || !Name) { + if (unsigned FileNum = DIE->getAttributeValueAsUnsignedConstant( + &U.getOrigUnit(), dwarf::DW_AT_decl_file, 0)) { + if (const auto *LT = U.getOrigUnit().getContext().getLineTableForUnit( + &U.getOrigUnit())) { + // FIXME: dsymutil-classic compatibility. I'd rather not + // unique anything in anonymous namespaces, but if we do, then + // verify that the file and line correspond. + if (!Name && Tag == dwarf::DW_TAG_namespace) + FileNum = 1; + + // FIXME: Passing U.getOrigUnit().getCompilationDir() + // instead of "" would allow more uniquing, but for now, do + // it this way to match dsymutil-classic. + if (LT->getFileNameByIndex( + FileNum, "", + DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, + File)) { + Line = DIE->getAttributeValueAsUnsignedConstant( + &U.getOrigUnit(), dwarf::DW_AT_decl_line, 0); +#ifdef HAVE_REALPATH + // Cache the resolved paths, because calling realpath is expansive. + if (const char *ResolvedPath = U.getResolvedPath(FileNum)) { + File = ResolvedPath; + } else { + char RealPath[PATH_MAX + 1]; + RealPath[PATH_MAX] = 0; + if (::realpath(File.c_str(), RealPath)) + File = RealPath; + U.setResolvedPath(FileNum, File); + } +#endif + FileRef = StringPool.internString(File); + } + } + } + } + } + + if (!Line && NameRef.empty()) + return PointerIntPair(nullptr); + + // We hash NameRef, which is the mangled name, in order to get most + // overloaded functions resolve correctly. + // + // Strictly speaking, hashing the Tag is only necessary for a + // DW_TAG_module, to prevent uniquing of a module and a namespace + // with the same name. + // + // FIXME: dsymutil-classic won't unique the same type presented + // once as a struct and once as a class. Using the Tag in the fully + // qualified name hash to get the same effect. + unsigned Hash = hash_combine(Context.getQualifiedNameHash(), Tag, NameRef); + + // FIXME: dsymutil-classic compatibility: when we don't have a name, + // use the filename. + if (Tag == dwarf::DW_TAG_namespace && NameRef == "(anonymous namespace)") + Hash = hash_combine(Hash, FileRef); + + // Now look if this context already exists. + DeclContext Key(Hash, Line, ByteSize, Tag, NameRef, FileRef, Context); + auto ContextIter = Contexts.find(&Key); + + if (ContextIter == Contexts.end()) { + // The context wasn't found. + bool Inserted; + DeclContext *NewContext = + new (Allocator) DeclContext(Hash, Line, ByteSize, Tag, NameRef, FileRef, + Context, DIE, U.getUniqueID()); + std::tie(ContextIter, Inserted) = Contexts.insert(NewContext); + assert(Inserted && "Failed to insert DeclContext"); + (void)Inserted; + } else if (Tag != dwarf::DW_TAG_namespace && + !(*ContextIter)->setLastSeenDIE(U, DIE)) { + // The context was found, but it is ambiguous with another context + // in the same file. Mark it invalid. + return PointerIntPair(*ContextIter, /* Invalid= */ 1); + } + + assert(ContextIter != Contexts.end()); + // FIXME: dsymutil-classic compatibility. Union types aren't + // uniques, but their children might be. + if ((Tag == dwarf::DW_TAG_subprogram && + Context.getTag() != dwarf::DW_TAG_structure_type && + Context.getTag() != dwarf::DW_TAG_class_type) || + (Tag == dwarf::DW_TAG_union_type)) + return PointerIntPair(*ContextIter, /* Invalid= */ 1); + + return PointerIntPair(*ContextIter); } -/// \brief Resolve the DIE attribute reference that has been -/// extracted in \p RefValue. The resulting DIE migh be in another -/// CompileUnit which is stored into \p ReferencedCU. -/// \returns null if resolving fails for any reason. -const DWARFDebugInfoEntryMinimal *DwarfLinker::resolveDIEReference( - DWARFFormValue &RefValue, const DWARFUnit &Unit, - const DWARFDebugInfoEntryMinimal &DIE, CompileUnit *&RefCU) { - assert(RefValue.isFormClass(DWARFFormValue::FC_Reference)); - uint64_t RefOffset = *RefValue.getAsReference(&Unit); +bool DwarfLinker::DIECloner::getDIENames(const DWARFDebugInfoEntryMinimal &Die, + DWARFUnit &U, AttributesInfo &Info) { + // FIXME: a bit wasteful as the first getName might return the + // short name. + if (!Info.MangledName && + (Info.MangledName = Die.getName(&U, DINameKind::LinkageName))) + Info.MangledNameOffset = + Linker.StringPool.getStringOffset(Info.MangledName); - if ((RefCU = getUnitForOffset(RefOffset))) - if (const auto *RefDie = RefCU->getOrigUnit().getDIEForOffset(RefOffset)) - return RefDie; + if (!Info.Name && (Info.Name = Die.getName(&U, DINameKind::ShortName))) + Info.NameOffset = Linker.StringPool.getStringOffset(Info.Name); - reportWarning("could not find referenced DIE", &Unit, &DIE); - return nullptr; + return Info.Name || Info.MangledName; } /// \brief Report a warning to the user, optionaly including /// information about a specific \p DIE related to the warning. void DwarfLinker::reportWarning(const Twine &Warning, const DWARFUnit *Unit, - const DWARFDebugInfoEntryMinimal *DIE) { + const DWARFDebugInfoEntryMinimal *DIE) const { StringRef Context = ""; if (CurrentDebugObject) Context = CurrentDebugObject->getObjectFilename(); @@ -670,17 +1743,70 @@ bool DwarfLinker::createStreamer(Triple TheTriple, StringRef OutputFilename) { return Streamer->init(TheTriple, OutputFilename); } -/// \brief Recursive helper to gather the child->parent relationships in the -/// original compile unit. -static void gatherDIEParents(const DWARFDebugInfoEntryMinimal *DIE, - unsigned ParentIdx, CompileUnit &CU) { +/// 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 DWARFDebugInfoEntryMinimal *DIE, + unsigned ParentIdx, CompileUnit &CU, + DeclContext *CurrentDeclContext, + NonRelocatableStringpool &StringPool, + DeclContextTree &Contexts, + bool InImportedModule = false) { unsigned MyIdx = CU.getOrigUnit().getDIEIndex(DIE); - CU.getInfo(MyIdx).ParentIdx = ParentIdx; + 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 && + DIE->getAttributeValueAsString(&CU.getOrigUnit(), 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(); + } else + Info.Ctxt = CurrentDeclContext = nullptr; + } + Info.Prune = InImportedModule; if (DIE->hasChildren()) for (auto *Child = DIE->getFirstChild(); Child && !Child->isNULL(); Child = Child->getSibling()) - gatherDIEParents(Child, MyIdx, CU); + Info.Prune &= analyzeContextInfo(Child, MyIdx, CU, CurrentDeclContext, + StringPool, Contexts, 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) || + DIE->getAttributeValueAsUnsignedConstant( + &CU.getOrigUnit(), dwarf::DW_AT_declaration, 0); + + // Don't prune it if there is no definition for the DIE. + Info.Prune &= Info.Ctxt && Info.Ctxt->getCanonicalDIEOffset(); + + return Info.Prune; } static bool dieNeedsChildrenToBeMeaningful(uint32_t Tag) { @@ -698,19 +1824,45 @@ static bool dieNeedsChildrenToBeMeaningful(uint32_t Tag) { llvm_unreachable("Invalid Tag"); } -void DwarfLinker::startDebugObject(DWARFContext &Dwarf) { +static unsigned getRefAddrSize(const DWARFUnit &U) { + if (U.getVersion() == 2) + return U.getAddressByteSize(); + return 4; +} + +void DwarfLinker::startDebugObject(DWARFContext &Dwarf, DebugMapObject &Obj) { Units.reserve(Dwarf.getNumCompileUnits()); - NextValidReloc = 0; + // 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: + // - obviously this one is global, while the other ones are per-unit. + // - 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 : Obj.symbols()) { + const auto &Mapping = Entry.getValue(); + if (Mapping.Size) + Ranges[Mapping.ObjectAddress] = std::make_pair( + Mapping.ObjectAddress + Mapping.Size, + int64_t(Mapping.BinaryAddress) - Mapping.ObjectAddress); + } } void DwarfLinker::endDebugObject() { Units.clear(); - ValidRelocs.clear(); + Ranges.clear(); - for (auto *Block : DIEBlocks) - Block->~DIEBlock(); - for (auto *Loc : DIELocs) - Loc->~DIELoc(); + 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(); @@ -720,9 +1872,10 @@ void DwarfLinker::endDebugObject() { /// \brief 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::findValidRelocsMachO(const object::SectionRef &Section, - const object::MachOObjectFile &Obj, - const DebugMapObject &DMO) { +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); @@ -731,9 +1884,9 @@ void DwarfLinker::findValidRelocsMachO(const object::SectionRef &Section, object::DataRefImpl RelocDataRef = Reloc.getRawDataRefImpl(); MachO::any_relocation_info MachOReloc = Obj.getRelocation(RelocDataRef); unsigned RelocSize = 1 << Obj.getAnyRelocationLength(MachOReloc); - uint64_t Offset64; - if ((RelocSize != 4 && RelocSize != 8) || Reloc.getOffset(Offset64)) { - reportWarning(" unsupported relocation in debug_info section."); + uint64_t Offset64 = Reloc.getOffset(); + if ((RelocSize != 4 && RelocSize != 8)) { + Linker.reportWarning(" unsupported relocation in debug_info section."); continue; } uint32_t Offset = Offset64; @@ -742,12 +1895,12 @@ void DwarfLinker::findValidRelocsMachO(const object::SectionRef &Section, auto Sym = Reloc.getSymbol(); if (Sym != Obj.symbol_end()) { - StringRef SymbolName; - if (Sym->getName(SymbolName)) { - reportWarning("error getting relocation symbol name."); + ErrorOr SymbolName = Sym->getName(); + if (!SymbolName) { + Linker.reportWarning("error getting relocation symbol name."); continue; } - if (const auto *Mapping = DMO.lookupSymbol(SymbolName)) + if (const auto *Mapping = DMO.lookupSymbol(*SymbolName)) ValidRelocs.emplace_back(Offset64, RelocSize, Addend, Mapping); } else if (const auto *Mapping = DMO.lookupObjectAddress(Addend)) { // Do not store the addend. The addend was the address of the @@ -760,14 +1913,15 @@ void DwarfLinker::findValidRelocsMachO(const object::SectionRef &Section, /// \brief Dispatch the valid relocation finding logic to the /// appropriate handler depending on the object file format. -bool DwarfLinker::findValidRelocs(const object::SectionRef &Section, - const object::ObjectFile &Obj, - const DebugMapObject &DMO) { +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(&Obj)) findValidRelocsMachO(Section, *MachOObj, DMO); else - reportWarning(Twine("unsupported object file type: ") + Obj.getFileName()); + Linker.reportWarning(Twine("unsupported object file type: ") + + Obj.getFileName()); if (ValidRelocs.empty()) return false; @@ -785,8 +1939,9 @@ bool DwarfLinker::findValidRelocs(const object::SectionRef &Section, /// link by indicating which DIEs refer to symbols present in the /// linked binary. /// \returns wether there are any valid relocations in the debug info. -bool DwarfLinker::findValidRelocsInDebugInfo(const object::ObjectFile &Obj, - const DebugMapObject &DMO) { +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; @@ -805,8 +1960,9 @@ bool DwarfLinker::findValidRelocsInDebugInfo(const object::ObjectFile &Obj, /// 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::hasValidRelocation(uint32_t StartOffset, uint32_t EndOffset, - CompileUnit::DIEInfo &Info) { +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()) @@ -825,14 +1981,15 @@ bool DwarfLinker::hasValidRelocation(uint32_t StartOffset, uint32_t EndOffset, return false; const auto &ValidReloc = ValidRelocs[NextValidReloc++]; - if (Options.Verbose) + const auto &Mapping = ValidReloc.Mapping->getValue(); + if (Linker.Options.Verbose) outs() << "Found valid debug map entry: " << ValidReloc.Mapping->getKey() << " " << format("\t%016" PRIx64 " => %016" PRIx64, - ValidReloc.Mapping->getValue().ObjectAddress, - ValidReloc.Mapping->getValue().BinaryAddress); + uint64_t(Mapping.ObjectAddress), + uint64_t(Mapping.BinaryAddress)); - Info.Address = - ValidReloc.Mapping->getValue().BinaryAddress + ValidReloc.Addend; + Info.AddrAdjust = int64_t(Mapping.BinaryAddress) + ValidReloc.Addend - + Mapping.ObjectAddress; Info.InDebugMap = true; return true; } @@ -858,9 +2015,11 @@ getAttributeOffsets(const DWARFAbbreviationDeclaration *Abbrev, unsigned Idx, /// \brief Check if a variable describing DIE should be kept. /// \returns updated TraversalFlags. -unsigned DwarfLinker::shouldKeepVariableDIE( - const DWARFDebugInfoEntryMinimal &DIE, CompileUnit &Unit, - CompileUnit::DIEInfo &MyInfo, unsigned Flags) { +unsigned DwarfLinker::shouldKeepVariableDIE(RelocationManager &RelocMgr, + const DWARFDebugInfoEntryMinimal &DIE, + CompileUnit &Unit, + CompileUnit::DIEInfo &MyInfo, + unsigned Flags) { const auto *Abbrev = DIE.getAbbreviationDeclarationPtr(); // Global variables with constant value can always be kept. @@ -885,7 +2044,7 @@ unsigned DwarfLinker::shouldKeepVariableDIE( // 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 (!hasValidRelocation(LocationOffset, LocationEndOffset, MyInfo) || + if (!RelocMgr.hasValidRelocation(LocationOffset, LocationEndOffset, MyInfo) || (Flags & TF_InFunctionScope)) return Flags; @@ -898,6 +2057,7 @@ unsigned DwarfLinker::shouldKeepVariableDIE( /// \brief Check if a function describing DIE should be kept. /// \returns updated TraversalFlags. unsigned DwarfLinker::shouldKeepSubprogramDIE( + RelocationManager &RelocMgr, const DWARFDebugInfoEntryMinimal &DIE, CompileUnit &Unit, CompileUnit::DIEInfo &MyInfo, unsigned Flags) { const auto *Abbrev = DIE.getAbbreviationDeclarationPtr(); @@ -918,27 +2078,48 @@ unsigned DwarfLinker::shouldKeepSubprogramDIE( DIE.getAttributeValueAsAddress(&OrigUnit, dwarf::DW_AT_low_pc, -1ULL); assert(LowPc != -1ULL && "low_pc attribute is not an address."); if (LowPc == -1ULL || - !hasValidRelocation(LowPcOffset, LowPcEndOffset, MyInfo)) + !RelocMgr.hasValidRelocation(LowPcOffset, LowPcEndOffset, MyInfo)) return Flags; if (Options.Verbose) DIE.dump(outs(), const_cast(&OrigUnit), 0, 8 /* Indent */); - return Flags | TF_Keep; + Flags |= TF_Keep; + + DWARFFormValue HighPcValue; + if (!DIE.getAttributeValue(&OrigUnit, dwarf::DW_AT_high_pc, HighPcValue)) { + reportWarning("Function without high_pc. Range will be discarded.\n", + &OrigUnit, &DIE); + return Flags; + } + + uint64_t HighPc; + if (HighPcValue.isFormClass(DWARFFormValue::FC_Address)) { + HighPc = *HighPcValue.getAsAddress(&OrigUnit); + } else { + assert(HighPcValue.isFormClass(DWARFFormValue::FC_Constant)); + HighPc = LowPc + *HighPcValue.getAsUnsignedConstant(); + } + + // Replace the debug map range with a more accurate one. + Ranges[LowPc] = std::make_pair(HighPc, MyInfo.AddrAdjust); + Unit.addFunctionRange(LowPc, HighPc, MyInfo.AddrAdjust); + return Flags; } /// \brief Check if a DIE should be kept. /// \returns updated TraversalFlags. -unsigned DwarfLinker::shouldKeepDIE(const DWARFDebugInfoEntryMinimal &DIE, +unsigned DwarfLinker::shouldKeepDIE(RelocationManager &RelocMgr, + const DWARFDebugInfoEntryMinimal &DIE, CompileUnit &Unit, CompileUnit::DIEInfo &MyInfo, unsigned Flags) { switch (DIE.getTag()) { case dwarf::DW_TAG_constant: case dwarf::DW_TAG_variable: - return shouldKeepVariableDIE(DIE, Unit, MyInfo, Flags); + return shouldKeepVariableDIE(RelocMgr, DIE, Unit, MyInfo, Flags); case dwarf::DW_TAG_subprogram: - return shouldKeepSubprogramDIE(DIE, Unit, MyInfo, Flags); + return shouldKeepSubprogramDIE(RelocMgr, DIE, Unit, MyInfo, Flags); case dwarf::DW_TAG_module: case dwarf::DW_TAG_imported_module: case dwarf::DW_TAG_imported_declaration: @@ -958,26 +2139,28 @@ unsigned DwarfLinker::shouldKeepDIE(const DWARFDebugInfoEntryMinimal &DIE, /// 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::keepDIEAndDenpendencies(const DWARFDebugInfoEntryMinimal &DIE, +void DwarfLinker::keepDIEAndDependencies(RelocationManager &RelocMgr, + const DWARFDebugInfoEntryMinimal &Die, CompileUnit::DIEInfo &MyInfo, const DebugMapObject &DMO, - CompileUnit &CU, unsigned Flags) { + CompileUnit &CU, bool UseODR) { const DWARFUnit &Unit = CU.getOrigUnit(); MyInfo.Keep = true; // First mark all the parent chain as kept. unsigned AncestorIdx = MyInfo.ParentIdx; while (!CU.getInfo(AncestorIdx).Keep) { - lookForDIEsToKeep(*Unit.getDIEAtIndex(AncestorIdx), DMO, CU, - TF_ParentWalk | TF_Keep | TF_DependencyWalk); + unsigned ODRFlag = UseODR ? TF_ODR : 0; + lookForDIEsToKeep(RelocMgr, *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. DataExtractor Data = Unit.getDebugInfoExtractor(); - const auto *Abbrev = DIE.getAbbreviationDeclarationPtr(); - uint32_t Offset = DIE.getOffset() + getULEB128Size(Abbrev->getCode()); + const auto *Abbrev = Die.getAbbreviationDeclarationPtr(); + uint32_t Offset = Die.getOffset() + getULEB128Size(Abbrev->getCode()); // Mark all DIEs referenced through atttributes as kept. for (const auto &AttrSpec : Abbrev->attributes()) { @@ -990,9 +2173,33 @@ void DwarfLinker::keepDIEAndDenpendencies(const DWARFDebugInfoEntryMinimal &DIE, Val.extractValue(Data, &Offset, &Unit); CompileUnit *ReferencedCU; - if (const auto *RefDIE = resolveDIEReference(Val, Unit, DIE, ReferencedCU)) - lookForDIEsToKeep(*RefDIE, DMO, *ReferencedCU, - TF_Keep | TF_DependencyWalk); + if (const auto *RefDIE = + resolveDIEReference(*this, MutableArrayRef(Units), Val, + Unit, Die, ReferencedCU)) { + uint32_t RefIdx = ReferencedCU->getOrigUnit().getDIEIndex(RefDIE); + CompileUnit::DIEInfo &Info = ReferencedCU->getInfo(RefIdx); + // 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 && 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, *RefDIE, DMO, *ReferencedCU, + TF_Keep | TF_DependencyWalk | ODRFlag); + } } } @@ -1008,12 +2215,15 @@ void DwarfLinker::keepDIEAndDenpendencies(const DWARFDebugInfoEntryMinimal &DIE, /// 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. -void DwarfLinker::lookForDIEsToKeep(const DWARFDebugInfoEntryMinimal &DIE, +void DwarfLinker::lookForDIEsToKeep(RelocationManager &RelocMgr, + const DWARFDebugInfoEntryMinimal &Die, const DebugMapObject &DMO, CompileUnit &CU, unsigned Flags) { - unsigned Idx = CU.getOrigUnit().getDIEIndex(&DIE); + unsigned Idx = CU.getOrigUnit().getDIEIndex(&Die); CompileUnit::DIEInfo &MyInfo = CU.getInfo(Idx); bool AlreadyKept = MyInfo.Keep; + if (MyInfo.Prune) + return; // 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 @@ -1021,30 +2231,31 @@ void DwarfLinker::lookForDIEsToKeep(const DWARFDebugInfoEntryMinimal &DIE, if ((Flags & TF_DependencyWalk) && AlreadyKept) return; - // We must not call shouldKeepDIE while called from keepDIEAndDenpendencies, + // We must not call shouldKeepDIE while called from keepDIEAndDependencies, // because it would screw up the relocation finding logic. if (!(Flags & TF_DependencyWalk)) - Flags = shouldKeepDIE(DIE, CU, MyInfo, Flags); + Flags = shouldKeepDIE(RelocMgr, Die, CU, MyInfo, Flags); // If it is a newly kept DIE mark it as well as all its dependencies as kept. - if (!AlreadyKept && (Flags & TF_Keep)) - keepDIEAndDenpendencies(DIE, MyInfo, DMO, CU, Flags); - + if (!AlreadyKept && (Flags & TF_Keep)) { + bool UseOdr = (Flags & TF_DependencyWalk) ? (Flags & TF_ODR) : CU.hasODR(); + keepDIEAndDependencies(RelocMgr, 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(DIE.getTag())) + if (dieNeedsChildrenToBeMeaningful(Die.getTag())) Flags &= ~TF_ParentWalk; - if (!DIE.hasChildren() || (Flags & TF_ParentWalk)) + if (!Die.hasChildren() || (Flags & TF_ParentWalk)) return; - for (auto *Child = DIE.getFirstChild(); Child && !Child->isNULL(); + for (auto *Child = Die.getFirstChild(); Child && !Child->isNULL(); Child = Child->getSibling()) - lookForDIEsToKeep(*Child, DMO, CU, Flags); + lookForDIEsToKeep(RelocMgr, *Child, DMO, CU, Flags); } /// \brief Assign an abbreviation numer to \p Abbrev. @@ -1067,161 +2278,227 @@ void DwarfLinker::AssignAbbrev(DIEAbbrev &Abbrev) { } else { // Add to abbreviation list. Abbreviations.push_back( - new DIEAbbrev(Abbrev.getTag(), Abbrev.hasChildren())); + llvm::make_unique(Abbrev.getTag(), Abbrev.hasChildren())); for (const auto &Attr : Abbrev.getData()) Abbreviations.back()->AddAttribute(Attr.getAttribute(), Attr.getForm()); - AbbreviationsSet.InsertNode(Abbreviations.back(), InsertToken); + AbbreviationsSet.InsertNode(Abbreviations.back().get(), InsertToken); // Assign the unique abbreviation number. Abbrev.setNumber(Abbreviations.size()); Abbreviations.back()->setNumber(Abbreviations.size()); } } -/// \brief Clone a string attribute described by \p AttrSpec and add -/// it to \p Die. -/// \returns the size of the new attribute. -unsigned DwarfLinker::cloneStringAttribute(DIE &Die, AttributeSpec AttrSpec, - const DWARFFormValue &Val, - const DWARFUnit &U) { +unsigned DwarfLinker::DIECloner::cloneStringAttribute(DIE &Die, + AttributeSpec AttrSpec, + const DWARFFormValue &Val, + const DWARFUnit &U) { // Switch everything to out of line strings. const char *String = *Val.getAsCString(&U); - unsigned Offset = StringPool.getStringOffset(String); - Die.addValue(dwarf::Attribute(AttrSpec.Attr), dwarf::DW_FORM_strp, - new (DIEAlloc) DIEInteger(Offset)); + unsigned Offset = Linker.StringPool.getStringOffset(String); + Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), dwarf::DW_FORM_strp, + DIEInteger(Offset)); return 4; } -/// \brief Clone an attribute referencing another DIE and add -/// it to \p Die. -/// \returns the size of the new attribute. -unsigned DwarfLinker::cloneDieReferenceAttribute( +unsigned DwarfLinker::DIECloner::cloneDieReferenceAttribute( DIE &Die, const DWARFDebugInfoEntryMinimal &InputDIE, AttributeSpec AttrSpec, unsigned AttrSize, const DWARFFormValue &Val, - const DWARFUnit &U) { + CompileUnit &Unit) { + const DWARFUnit &U = Unit.getOrigUnit(); uint32_t Ref = *Val.getAsReference(&U); DIE *NewRefDie = nullptr; CompileUnit *RefUnit = nullptr; - const DWARFDebugInfoEntryMinimal *RefDie = nullptr; - - if (!(RefUnit = getUnitForOffset(Ref)) || - !(RefDie = RefUnit->getOrigUnit().getDIEForOffset(Ref))) { - const char *AttributeString = dwarf::AttributeString(AttrSpec.Attr); - if (!AttributeString) - AttributeString = "DW_AT_???"; - reportWarning(Twine("Missing DIE for ref in attribute ") + AttributeString + - ". Dropping.", - &U, &InputDIE); + DeclContext *Ctxt = nullptr; + + const DWARFDebugInfoEntryMinimal *RefDie = + resolveDIEReference(Linker, CompileUnits, Val, U, InputDIE, RefUnit); + + // If the referenced DIE is not found, drop the attribute. + if (!RefDie) 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 getRefAddrSize(U); + } + } + 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 = new DIE(dwarf::Tag(RefDie->getTag())); + RefInfo.Clone = DIE::get(DIEAlloc, dwarf::Tag(RefDie->getTag())); } NewRefDie = RefInfo.Clone; - if (AttrSpec.Form == dwarf::DW_FORM_ref_addr) { + 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. - DIEInteger *Attr; + uint64_t Attr; if (Ref < InputDIE.getOffset()) { // We must have already cloned that DIE. uint32_t NewRefOffset = RefUnit->getStartOffset() + NewRefDie->getOffset(); - Attr = new (DIEAlloc) DIEInteger(NewRefOffset); + 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 = new (DIEAlloc) DIEInteger(0xBADDEF); - RefUnit->noteForwardReference(NewRefDie, Attr); + Attr = 0xBADDEF; + Unit.noteForwardReference( + NewRefDie, RefUnit, Ctxt, + Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), + dwarf::DW_FORM_ref_addr, DIEInteger(Attr))); } - Die.addValue(dwarf::Attribute(AttrSpec.Attr), dwarf::DW_FORM_ref_addr, - Attr); - return AttrSize; + return getRefAddrSize(U); } - Die.addValue(dwarf::Attribute(AttrSpec.Attr), dwarf::Form(AttrSpec.Form), - new (DIEAlloc) DIEEntry(*NewRefDie)); + Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), + dwarf::Form(AttrSpec.Form), DIEEntry(*NewRefDie)); return AttrSize; } -/// \brief Clone an attribute of block form (locations, constants) and add -/// it to \p Die. -/// \returns the size of the new attribute. -unsigned DwarfLinker::cloneBlockAttribute(DIE &Die, AttributeSpec AttrSpec, - const DWARFFormValue &Val, - unsigned AttrSize) { - DIE *Attr; - DIEValue *Value; +unsigned DwarfLinker::DIECloner::cloneBlockAttribute(DIE &Die, + AttributeSpec AttrSpec, + const DWARFFormValue &Val, + unsigned AttrSize) { + DIEValueList *Attr; + DIEValue Value; DIELoc *Loc = nullptr; DIEBlock *Block = nullptr; // Just copy the block data over. - if (AttrSpec.Attr == dwarf::DW_FORM_exprloc) { - Loc = new (DIEAlloc) DIELoc(); - DIELocs.push_back(Loc); + if (AttrSpec.Form == dwarf::DW_FORM_exprloc) { + Loc = new (DIEAlloc) DIELoc; + Linker.DIELocs.push_back(Loc); } else { - Block = new (DIEAlloc) DIEBlock(); - DIEBlocks.push_back(Block); + Block = new (DIEAlloc) DIEBlock; + Linker.DIEBlocks.push_back(Block); } - Attr = Loc ? static_cast(Loc) : static_cast(Block); - Value = Loc ? static_cast(Loc) : static_cast(Block); + Attr = Loc ? static_cast(Loc) + : static_cast(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); ArrayRef Bytes = *Val.getAsBlock(); for (auto Byte : Bytes) - Attr->addValue(static_cast(0), dwarf::DW_FORM_data1, - new (DIEAlloc) DIEInteger(Byte)); + Attr->addValue(DIEAlloc, static_cast(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 (Streamer) { + if (Linker.Streamer) { + auto *AsmPrinter = &Linker.Streamer->getAsmPrinter(); if (Loc) - Loc->ComputeSize(&Streamer->getAsmPrinter()); + Loc->ComputeSize(AsmPrinter); else - Block->ComputeSize(&Streamer->getAsmPrinter()); + Block->ComputeSize(AsmPrinter); } - Die.addValue(dwarf::Attribute(AttrSpec.Attr), dwarf::Form(AttrSpec.Form), - Value); + Die.addValue(DIEAlloc, Value); return AttrSize; } -/// \brief Clone a scalar attribute and add it to \p Die. -/// \returns the size of the new attribute. -unsigned DwarfLinker::cloneScalarAttribute( - DIE &Die, const DWARFDebugInfoEntryMinimal &InputDIE, const DWARFUnit &U, - AttributeSpec AttrSpec, const DWARFFormValue &Val, unsigned AttrSize) { +unsigned DwarfLinker::DIECloner::cloneAddressAttribute( + DIE &Die, AttributeSpec AttrSpec, const DWARFFormValue &Val, + const CompileUnit &Unit, AttributesInfo &Info) { + uint64_t Addr = *Val.getAsAddress(&Unit.getOrigUnit()); + 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 != UINT64_MAX ? Info.OrigLowPc : Addr) + + Info.PCOffset; + else if (Die.getTag() == dwarf::DW_TAG_compile_unit) { + Addr = Unit.getLowPc(); + if (Addr == UINT64_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(AttrSpec.Attr), + static_cast(AttrSpec.Form), DIEInteger(Addr)); + return Unit.getOrigUnit().getAddressByteSize(); +} + +unsigned DwarfLinker::DIECloner::cloneScalarAttribute( + DIE &Die, const DWARFDebugInfoEntryMinimal &InputDIE, CompileUnit &Unit, + AttributeSpec AttrSpec, const DWARFFormValue &Val, unsigned AttrSize, + AttributesInfo &Info) { uint64_t Value; - if (AttrSpec.Form == dwarf::DW_FORM_sec_offset) + 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 (AttrSpec.Form == dwarf::DW_FORM_addr) - Value = *Val.getAsAddress(&U); else if (auto OptionalValue = Val.getAsUnsignedConstant()) Value = *OptionalValue; else { - reportWarning("Unsupported scalar attribute form. Dropping attribute.", &U, - &InputDIE); + Linker.reportWarning( + "Unsupported scalar attribute form. Dropping attribute.", + &Unit.getOrigUnit(), &InputDIE); return 0; } - Die.addValue(dwarf::Attribute(AttrSpec.Attr), dwarf::Form(AttrSpec.Form), - new (DIEAlloc) DIEInteger(Value)); + 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); + + // 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. + 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; } /// \brief 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::cloneAttribute(DIE &Die, - const DWARFDebugInfoEntryMinimal &InputDIE, - CompileUnit &Unit, - const DWARFFormValue &Val, - const AttributeSpec AttrSpec, - unsigned AttrSize) { +unsigned DwarfLinker::DIECloner::cloneAttribute( + DIE &Die, const DWARFDebugInfoEntryMinimal &InputDIE, CompileUnit &Unit, + const DWARFFormValue &Val, const AttributeSpec AttrSpec, unsigned AttrSize, + AttributesInfo &Info) { const DWARFUnit &U = Unit.getOrigUnit(); switch (AttrSpec.Form) { @@ -1234,7 +2511,7 @@ unsigned DwarfLinker::cloneAttribute(DIE &Die, case dwarf::DW_FORM_ref4: case dwarf::DW_FORM_ref8: return cloneDieReferenceAttribute(Die, InputDIE, AttrSpec, AttrSize, Val, - U); + Unit); case dwarf::DW_FORM_block: case dwarf::DW_FORM_block1: case dwarf::DW_FORM_block2: @@ -1242,6 +2519,7 @@ unsigned DwarfLinker::cloneAttribute(DIE &Die, case dwarf::DW_FORM_exprloc: return cloneBlockAttribute(Die, AttrSpec, Val, AttrSize); 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: @@ -1251,10 +2529,12 @@ unsigned DwarfLinker::cloneAttribute(DIE &Die, case dwarf::DW_FORM_sec_offset: case dwarf::DW_FORM_flag: case dwarf::DW_FORM_flag_present: - return cloneScalarAttribute(Die, InputDIE, U, AttrSpec, Val, AttrSize); + return cloneScalarAttribute(Die, InputDIE, Unit, AttrSpec, Val, AttrSize, + Info); default: - reportWarning("Unsupported attribute form in cloneAttribute. Dropping.", &U, - &InputDIE); + Linker.reportWarning( + "Unsupported attribute form in cloneAttribute. Dropping.", &U, + &InputDIE); } return 0; @@ -1268,11 +2548,12 @@ unsigned DwarfLinker::cloneAttribute(DIE &Die, /// monotonic \p BaseOffset values. /// /// \returns wether any reloc has been applied. -bool DwarfLinker::applyValidRelocs(MutableArrayRef Data, - uint32_t BaseOffset, bool isLittleEndian) { +bool DwarfLinker::RelocationManager:: +applyValidRelocs(MutableArrayRef Data, uint32_t BaseOffset, + bool isLittleEndian) { assert((NextValidReloc == 0 || - BaseOffset > ValidRelocs[NextValidReloc - 1].Offset) && - "BaseOffset should only be increasing."); + BaseOffset > ValidRelocs[NextValidReloc - 1].Offset) && + "BaseOffset should only be increasing."); if (NextValidReloc >= ValidRelocs.size()) return false; @@ -1304,15 +2585,66 @@ bool DwarfLinker::applyValidRelocs(MutableArrayRef Data, return Applied; } -/// \brief Recursively clone \p InputDIE's subtrees that have been -/// selected to appear in the linked output. -/// -/// \param OutOffset is the Offset where the newly created DIE will -/// lie in the linked compile unit. -/// -/// \returns the cloned DIE object or null if nothing was selected. -DIE *DwarfLinker::cloneDIE(const DWARFDebugInfoEntryMinimal &InputDIE, - CompileUnit &Unit, uint32_t OutOffset) { +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_interface_type: + case dwarf::DW_TAG_unspecified_type: + case dwarf::DW_TAG_shared_type: + return true; + default: + break; + } + return false; +} + +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 (ie. 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 DWARFDebugInfoEntryMinimal &InputDIE, CompileUnit &Unit, + int64_t PCOffset, uint32_t OutOffset, unsigned Flags) { DWARFUnit &U = Unit.getOrigUnit(); unsigned Idx = U.getDIEIndex(&InputDIE); CompileUnit::DIEInfo &Info = Unit.getInfo(Idx); @@ -1326,13 +2658,29 @@ DIE *DwarfLinker::cloneDIE(const DWARFDebugInfoEntryMinimal &InputDIE, // (see cloneDieReferenceAttribute()). DIE *Die = Info.Clone; if (!Die) - Die = Info.Clone = new DIE(dwarf::Tag(InputDIE.getTag())); + Die = Info.Clone = DIE::get(DIEAlloc, dwarf::Tag(InputDIE.getTag())); assert(Die->getTag() == InputDIE.getTag()); Die->setOffset(OutOffset); + if ((Unit.hasODR() || Unit.isClangModule()) && + 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. DataExtractor Data = U.getDebugInfoExtractor(); - uint32_t NextOffset = U.getDIEAtIndex(Idx + 1)->getOffset(); + // 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 aply a relocation to // it. After testing, it seems there is no performance downside to @@ -1340,7 +2688,22 @@ DIE *DwarfLinker::cloneDIE(const DWARFDebugInfoEntryMinimal &InputDIE, SmallString<40> DIECopy(Data.getData().substr(Offset, NextOffset - Offset)); Data = DataExtractor(DIECopy, Data.isLittleEndian(), Data.getAddressSize()); // Modify the copy with relocated addresses. - applyValidRelocs(DIECopy, Offset, Data.isLittleEndian()); + 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 + // independantly by the linker). The computation of the actual + // high_pc value is done in cloneAddressAttribute(). + AttrInfo.OrigHighPc = + InputDIE.getAttributeValueAsAddress(&U, 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 = + InputDIE.getAttributeValueAsAddress(&U, dwarf::DW_AT_low_pc, UINT64_MAX); + } // Reset the Offset to 0 as we will be working on the local copy of // the data. @@ -1349,28 +2712,83 @@ DIE *DwarfLinker::cloneDIE(const DWARFDebugInfoEntryMinimal &InputDIE, 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) + Flags |= TF_SkipPC; + } + + bool Copied = false; for (const auto &AttrSpec : Abbrev->attributes()) { + if (shouldSkipAttribute(AttrSpec, Die->getTag(), Info.InDebugMap, + Flags & TF_SkipPC, Flags & TF_InFunctionScope)) { + DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset, &U); + // 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); AttrSize = Offset - AttrSize; - OutOffset += cloneAttribute(*Die, InputDIE, Unit, Val, AttrSpec, AttrSize); + OutOffset += + cloneAttribute(*Die, InputDIE, Unit, Val, AttrSpec, AttrSize, AttrInfo); + } + + // 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) && + Tag != dwarf::DW_TAG_compile_unit && + getDIENames(InputDIE, Unit.getOrigUnit(), AttrInfo)) { + if (AttrInfo.MangledName && AttrInfo.MangledName != AttrInfo.Name) + Unit.addNameAccelerator(Die, AttrInfo.MangledName, + AttrInfo.MangledNameOffset, + Tag == dwarf::DW_TAG_inlined_subroutine); + if (AttrInfo.Name) + Unit.addNameAccelerator(Die, AttrInfo.Name, AttrInfo.NameOffset, + Tag == dwarf::DW_TAG_inlined_subroutine); + } else if (isTypeTag(Tag) && !AttrInfo.IsDeclaration && + getDIENames(InputDIE, Unit.getOrigUnit(), AttrInfo)) { + Unit.addTypeAccelerator(Die, AttrInfo.Name, AttrInfo.NameOffset); + } + + // Determine whether there are any children that we want to keep. + bool HasChildren = false; + for (auto *Child = InputDIE.getFirstChild(); Child && !Child->isNULL(); + Child = Child->getSibling()) { + unsigned Idx = U.getDIEIndex(Child); + if (Unit.getInfo(Idx).Keep) { + HasChildren = true; + break; + } } - DIEAbbrev &NewAbbrev = Die->getAbbrev(); - // If a scope DIE is kept, we must have kept at least one child. If - // it's not the case, we'll just be emitting one wasteful end of - // children marker, but things won't break. - if (InputDIE.hasChildren()) + DIEAbbrev NewAbbrev = Die->generateAbbrev(); + if (HasChildren) NewAbbrev.setChildrenFlag(dwarf::DW_CHILDREN_yes); // Assign a permanent abbrev number - AssignAbbrev(Die->getAbbrev()); + Linker.AssignAbbrev(NewAbbrev); + Die->setAbbrevNumber(NewAbbrev.getNumber()); // Add the size of the abbreviation number to the output offset. OutOffset += getULEB128Size(Die->getAbbrevNumber()); - if (!Abbrev->hasChildren()) { + if (!HasChildren) { // Update our size. Die->setSize(OutOffset - Die->getOffset()); return Die; @@ -1379,8 +2797,8 @@ DIE *DwarfLinker::cloneDIE(const DWARFDebugInfoEntryMinimal &InputDIE, // Recursively clone children. for (auto *Child = InputDIE.getFirstChild(); Child && !Child->isNULL(); Child = Child->getSibling()) { - if (DIE *Clone = cloneDIE(*Child, Unit, OutOffset)) { - Die->addChild(std::unique_ptr(Clone)); + if (DIE *Clone = cloneDIE(*Child, Unit, PCOffset, OutOffset, Flags)) { + Die->addChild(Clone); OutOffset = Clone->getOffset() + Clone->getSize(); } } @@ -1392,32 +2810,536 @@ DIE *DwarfLinker::cloneDIE(const DWARFDebugInfoEntryMinimal &InputDIE, return Die; } -bool DwarfLinker::link(const DebugMap &Map) { +/// \brief 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 { + DWARFDebugRangeList RangeList; + const auto &FunctionRanges = Unit.getFunctionRanges(); + unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize(); + DataExtractor RangeExtractor(OrigDwarf.getRangeSection(), + OrigDwarf.isLittleEndian(), AddressSize); + auto InvalidRange = FunctionRanges.end(), CurrRange = InvalidRange; + DWARFUnit &OrigUnit = Unit.getOrigUnit(); + const auto *OrigUnitDie = OrigUnit.getUnitDIE(false); + uint64_t OrigLowPc = OrigUnitDie->getAttributeValueAsAddress( + &OrigUnit, 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 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()); + RangeList.extract(RangeExtractor, &Offset); + 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."); + continue; + } + } + } + + Streamer->emitRangesEntries(UnitPcOffset, OrigLowPc, CurrRange, Entries, + AddressSize); + } +} + +/// \brief 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(Attr)); +} + +/// \brief Insert the new line info sequence \p Seq into the current +/// set of already linked line info \p Rows. +static void insertLineSequence(std::vector &Seq, + std::vector &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!"); +} + +/// \brief 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) { + const DWARFDebugInfoEntryMinimal *CUDie = Unit.getOrigUnit().getUnitDIE(); + uint64_t StmtList = CUDie->getAttributeValueAsSectionOffset( + &Unit.getOrigUnit(), dwarf::DW_AT_stmt_list, -1ULL); + if (StmtList == -1ULL) + 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; + StringRef LineData = OrigDwarf.getLineSection().Data; + DataExtractor LineExtractor(LineData, OrigDwarf.isLittleEndian(), + Unit.getOrigUnit().getAddressByteSize()); + LineTable.parse(LineExtractor, &OrigDwarf.getLineSection().Relocs, + &StmtOffset); + + // This vector is the output line table. + std::vector NewRows; + NewRows.reserve(LineTable.Rows.size()); + + // Current sequence of rows being extracted, before being inserted + // in NewRows. + std::vector 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 dsynutil. 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 wether 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 < CurrRange.start() || + Row.Address > CurrRange.stop() || + (Row.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); + bool CurrRangeValid = + CurrRange != InvalidRange && CurrRange.start() <= Row.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); + if (Range != Ranges.begin() && Range != Ranges.end()) + --Range; + + if (Range != Ranges.end() && Range->first <= Row.Address && + Range->second.first >= Row.Address) { + StopAddress = Row.Address + Range->second.second; + } + } + } + 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 = 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 += CurrRange.value(); + Seq.emplace_back(Row); + + if (Row.EndSequence) + insertLineSequence(Seq, NewRows); + } + + // Finished extracting, now emit the line tables. + uint32_t PrologueEnd = StmtList + 10 + LineTable.Prologue.PrologueLength; + // FIXME: LLVM hardcodes it's 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.Version != 2 || + LineTable.Prologue.DefaultIsStmt != DWARF2_LINE_DEFAULT_IS_STMT || + LineTable.Prologue.OpcodeBase > 13) + reportWarning("line table paramters mismatch. Cannot emit."); + else { + 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) { + Streamer->emitPubNamesForUnit(Unit); + Streamer->emitPubTypesForUnit(Unit); +} + +/// \brief 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, + DWARFContext &OrigDwarf, + unsigned AddrSize) { + StringRef FrameData = OrigDwarf.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 LocalCIES; + + while (Data.isValidOffset(InputOffset)) { + uint32_t EntryOffset = InputOffset; + uint32_t InitialLength = Data.getU32(&InputOffset); + if (InitialLength == 0xFFFFFFFF) + return reportWarning("Dwarf64 bits no supported"); + + 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.first <= 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."); + + // 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.second, + 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); +} - if (Map.begin() == Map.end()) { - errs() << "Empty debug map.\n"; +static uint64_t getDwoId(const DWARFDebugInfoEntryMinimal &CUDie, + const DWARFUnit &Unit) { + uint64_t DwoId = + CUDie.getAttributeValueAsUnsignedConstant(&Unit, dwarf::DW_AT_dwo_id, 0); + if (!DwoId) + DwoId = CUDie.getAttributeValueAsUnsignedConstant(&Unit, + dwarf::DW_AT_GNU_dwo_id, 0); + return DwoId; +} + +bool DwarfLinker::registerModuleReference( + const DWARFDebugInfoEntryMinimal &CUDie, const DWARFUnit &Unit, + DebugMap &ModuleMap, unsigned Indent) { + std::string PCMfile = + CUDie.getAttributeValueAsString(&Unit, dwarf::DW_AT_dwo_name, ""); + if (PCMfile.empty()) + PCMfile = + CUDie.getAttributeValueAsString(&Unit, 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 = + CUDie.getAttributeValueAsString(&Unit, dwarf::DW_AT_comp_dir, ""); + uint64_t DwoId = getDwoId(CUDie, Unit); + + std::string Name = + CUDie.getAttributeValueAsString(&Unit, dwarf::DW_AT_name, ""); + if (Name.empty()) { + reportWarning("Anonymous module skeleton CU for " + PCMfile); + return true; + } + + if (Options.Verbose) { + outs().indent(Indent); + outs() << "Found clang module reference " << PCMfile; + } + + auto Cached = ClangModules.find(PCMfile); + if (Cached != ClangModules.end()) { + if (Cached->second != DwoId) + reportWarning(Twine("hash mismatch: this object file was built against a " + "different version of the module ") + PCMfile); + if (Options.Verbose) + outs() << " [cached].\n"; + return true; + } + if (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}); + loadClangModule(PCMfile, PCMpath, Name, DwoId, ModuleMap, Indent + 2); + return true; +} + +ErrorOr +DwarfLinker::loadObject(BinaryHolder &BinaryHolder, DebugMapObject &Obj, + const DebugMap &Map) { + auto ErrOrObjs = + BinaryHolder.GetObjectFiles(Obj.getObjectFilename(), Obj.getTimestamp()); + if (std::error_code EC = ErrOrObjs.getError()) { + reportWarning(Twine(Obj.getObjectFilename()) + ": " + EC.message()); + return EC; + } + auto ErrOrObj = BinaryHolder.Get(Map.getTriple()); + if (std::error_code EC = ErrOrObj.getError()) + reportWarning(Twine(Obj.getObjectFilename()) + ": " + EC.message()); + return ErrOrObj; +} + +void DwarfLinker::loadClangModule(StringRef Filename, StringRef ModulePath, + StringRef ModuleName, uint64_t DwoId, + DebugMap &ModuleMap, unsigned Indent) { + SmallString<80> Path(Options.PrependPath); + if (sys::path::is_relative(Filename)) + sys::path::append(Path, ModulePath, Filename); + else + sys::path::append(Path, Filename); + BinaryHolder ObjHolder(Options.Verbose); + auto &Obj = + ModuleMap.addDebugMapObject(Path, sys::TimeValue::PosixZeroTime()); + auto ErrOrObj = loadObject(ObjHolder, Obj, ModuleMap); + if (!ErrOrObj) { + ClangModules.erase(ClangModules.find(Filename)); + return; + } + + std::unique_ptr Unit; + + // Setup access to the debug info. + DWARFContextInMemory DwarfContext(*ErrOrObj); + RelocationManager RelocMgr(*this); + for (const auto &CU : DwarfContext.compile_units()) { + auto *CUDie = CU->getUnitDIE(false); + // Recursively get all modules imported by this one. + if (!registerModuleReference(*CUDie, *CU, ModuleMap, Indent)) { + if (Unit) { + errs() << Filename << ": Clang modules are expected to have exactly" + << " 1 compile unit.\n"; + exitDsymutil(1); + } + if (getDwoId(*CUDie, *CU) != DwoId) + reportWarning( + Twine("hash mismatch: this object file was built against a " + "different version of the module ") + Filename); + + // Add this module. + Unit = llvm::make_unique(*CU, UnitID++, !Options.NoODR, + ModuleName); + Unit->setHasInterestingContent(); + analyzeContextInfo(CUDie, 0, *Unit, &ODRContexts.getRoot(), StringPool, + ODRContexts); + // Keep everything. + Unit->markEverythingAsKept(); + } + } + if (Options.Verbose) { + outs().indent(Indent); + outs() << "cloning .debug_info from " << Filename << "\n"; + } + + DIECloner(*this, RelocMgr, DIEAlloc, MutableArrayRef(*Unit), + Options) + .cloneAllCompileUnits(DwarfContext); +} + +void DwarfLinker::DIECloner::cloneAllCompileUnits( + DWARFContextInMemory &DwarfContext) { + if (!Linker.Streamer) + return; + + for (auto &CurrentUnit : CompileUnits) { + const auto *InputDIE = CurrentUnit.getOrigUnit().getUnitDIE(); + CurrentUnit.setStartOffset(Linker.OutputDebugInfoSize); + DIE *OutputDIE = cloneDIE(*InputDIE, CurrentUnit, 0 /* PC offset */, + 11 /* Unit Header size */, 0); + CurrentUnit.setOutputUnitDIE(OutputDIE); + 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. + Linker.patchLineTableForUnit(CurrentUnit, DwarfContext); + if (!OutputDIE) + continue; + Linker.patchRangesForUnit(CurrentUnit, DwarfContext); + Linker.Streamer->emitLocationsForUnit(CurrentUnit, DwarfContext); + Linker.emitAcceleratorEntriesForUnit(CurrentUnit); + } + + if (Linker.Options.NoOutput) + return; + + // Emit all the compile unit's debug information. + for (auto &CurrentUnit : CompileUnits) { + Linker.generateUnitRanges(CurrentUnit); + CurrentUnit.fixupForwardReferences(); + Linker.Streamer->emitCompileUnitHeader(CurrentUnit); + if (!CurrentUnit.getOutputUnitDIE()) + continue; + Linker.Streamer->emitDIE(*CurrentUnit.getOutputUnitDIE()); } +} + +bool DwarfLinker::link(const DebugMap &Map) { if (!createStreamer(Map.getTriple(), OutputFilename)) return false; // Size of the DIEs (and headers) generated for the linked output. - uint64_t OutputDebugInfoSize = 0; + OutputDebugInfoSize = 0; + // A unique ID that identifies each compile unit. + UnitID = 0; + DebugMap ModuleMap(Map.getTriple(), Map.getBinaryPath()); for (const auto &Obj : Map.objects()) { CurrentDebugObject = Obj.get(); if (Options.Verbose) outs() << "DEBUG MAP OBJECT: " << Obj->getObjectFilename() << "\n"; - auto ErrOrObj = BinHolder.GetObjectFile(Obj->getObjectFilename()); - if (std::error_code EC = ErrOrObj.getError()) { - reportWarning(Twine(Obj->getObjectFilename()) + ": " + EC.message()); + auto ErrOrObj = loadObject(BinHolder, *Obj, Map); + if (!ErrOrObj) continue; - } // Look for relocations that correspond to debug map entries. - if (!findValidRelocsInDebugInfo(*ErrOrObj, *Obj)) { + RelocationManager RelocMgr(*this); + if (!RelocMgr.findValidRelocsInDebugInfo(*ErrOrObj, *Obj)) { if (Options.Verbose) outs() << "No valid relocations found. Skipping.\n"; continue; @@ -1425,56 +3347,44 @@ bool DwarfLinker::link(const DebugMap &Map) { // Setup access to the debug info. DWARFContextInMemory DwarfContext(*ErrOrObj); - startDebugObject(DwarfContext); + startDebugObject(DwarfContext, *Obj); - // In a first phase, just read in the debug info and store the DIE - // parent links that we will use during the next phase. + // In a first phase, just read in the debug info and load all clang modules. for (const auto &CU : DwarfContext.compile_units()) { - auto *CUDie = CU->getCompileUnitDIE(false); + auto *CUDie = CU->getUnitDIE(false); if (Options.Verbose) { outs() << "Input compilation unit:"; CUDie->dump(outs(), CU.get(), 0); } - Units.emplace_back(*CU); - gatherDIEParents(CUDie, 0, Units.back()); + + if (!registerModuleReference(*CUDie, *CU, ModuleMap)) + Units.emplace_back(*CU, UnitID++, !Options.NoODR, ""); } + // Now build the DIE parent links that we will use during the next phase. + for (auto &CurrentUnit : Units) + analyzeContextInfo(CurrentUnit.getOrigUnit().getUnitDIE(), 0, CurrentUnit, + &ODRContexts.getRoot(), StringPool, ODRContexts); + // Then mark all the DIEs that need to be present in the linked // output and collect some information about them. Note that this // loop can not be merged with the previous one becaue cross-cu // references require the ParentIdx to be setup for every CU in // the object file before calling this. for (auto &CurrentUnit : Units) - lookForDIEsToKeep(*CurrentUnit.getOrigUnit().getCompileUnitDIE(), *Obj, + lookForDIEsToKeep(RelocMgr, *CurrentUnit.getOrigUnit().getUnitDIE(), *Obj, CurrentUnit, 0); // The calls to applyValidRelocs inside cloneDIE will walk the // reloc array again (in the same way findValidRelocsInDebugInfo() // did). We need to reset the NextValidReloc index to the beginning. - NextValidReloc = 0; - - // Construct the output DIE tree by cloning the DIEs we chose to - // keep above. If there are no valid relocs, then there's nothing - // to clone/emit. - if (!ValidRelocs.empty()) - for (auto &CurrentUnit : Units) { - const auto *InputDIE = CurrentUnit.getOrigUnit().getCompileUnitDIE(); - CurrentUnit.setStartOffset(OutputDebugInfoSize); - DIE *OutputDIE = - cloneDIE(*InputDIE, CurrentUnit, 11 /* Unit Header size */); - CurrentUnit.setOutputUnitDIE(OutputDIE); - OutputDebugInfoSize = CurrentUnit.computeNextUnitOffset(); - } - - // Emit all the compile unit's debug information. - if (!ValidRelocs.empty() && !Options.NoOutput) - for (auto &CurrentUnit : Units) { - CurrentUnit.fixupForwardReferences(); - Streamer->emitCompileUnitHeader(CurrentUnit); - if (!CurrentUnit.getOutputUnitDIE()) - continue; - Streamer->emitDIE(*CurrentUnit.getOutputUnitDIE()); - } + RelocMgr.resetValidRelocs(); + if (RelocMgr.hasValidRelocs()) + DIECloner(*this, RelocMgr, DIEAlloc, Units, Options) + .cloneAllCompileUnits(DwarfContext); + if (!Options.NoOutput && !Units.empty()) + patchFrameInfoForObject(*Obj, DwarfContext, + Units[0].getOrigUnit().getAddressByteSize()); // Clean-up before starting working on the next object. endDebugObject(); @@ -1486,8 +3396,53 @@ bool DwarfLinker::link(const DebugMap &Map) { Streamer->emitStrings(StringPool); } - return Options.NoOutput ? true : Streamer->finish(); + return Options.NoOutput ? true : Streamer->finish(Map); +} +} + +/// \brief Get the offset of string \p S in the string table. This +/// can insert a new element or return the offset of a preexisitng +/// one. +uint32_t NonRelocatableStringpool::getStringOffset(StringRef S) { + if (S.empty() && !Strings.empty()) + return 0; + + std::pair Entry(0, nullptr); + MapTy::iterator It; + bool Inserted; + + // A non-empty string can't be at offset 0, so if we have an entry + // with a 0 offset, it must be a previously interned string. + std::tie(It, Inserted) = Strings.insert(std::make_pair(S, Entry)); + if (Inserted || It->getValue().first == 0) { + // Set offset and chain at the end of the entries list. + It->getValue().first = CurrentEndOffset; + CurrentEndOffset += S.size() + 1; // +1 for the '\0'. + Last->getValue().second = &*It; + Last = &*It; + } + return It->getValue().first; +} + +/// \brief Put \p S into the StringMap so that it gets permanent +/// storage, but do not actually link it in the chain of elements +/// that go into the output section. A latter call to +/// getStringOffset() with the same string will chain it though. +StringRef NonRelocatableStringpool::internString(StringRef S) { + std::pair Entry(0, nullptr); + auto InsertResult = Strings.insert(std::make_pair(S, Entry)); + return InsertResult.first->getKey(); +} + +void warn(const Twine &Warning, const Twine &Context) { + errs() << Twine("while processing ") + Context + ":\n"; + errs() << Twine("warning: ") + Warning + "\n"; } + +bool error(const Twine &Error, const Twine &Context) { + errs() << Twine("while processing ") + Context + ":\n"; + errs() << Twine("error: ") + Error + "\n"; + return false; } bool linkDwarf(StringRef OutputFilename, const DebugMap &DM,