//
//===----------------------------------------------------------------------===//
#include "DebugMap.h"
+#include "BinaryHolder.h"
+#include "DebugMap.h"
+#include "dsymutil.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/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
+#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
+#include "llvm/MC/MCAsmBackend.h"
+#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"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
+#include <string>
+#include <tuple>
+
+namespace llvm {
+namespace dsymutil {
+
+namespace {
+
+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;
+}
+
+template <typename KeyT, typename ValT>
+using HalfOpenIntervalMap =
+ IntervalMap<KeyT, ValT, IntervalMapImpl::NodeSizer<KeyT, ValT>::LeafSize,
+ IntervalMapHalfOpenInfo<KeyT>>;
+
+typedef HalfOpenIntervalMap<uint64_t, int64_t> 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();
+ }
+};
+
+/// \brief Stores all information relating to a compile unit, be it in
+/// its original instance in the object file to its brand new cloned
+/// and linked DIE tree.
+class CompileUnit {
+public:
+ /// \brief Information gathered about a DIE in the object file.
+ struct DIEInfo {
+ int64_t AddrAdjust; ///< Address offset to apply to the described entity.
+ 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?
+ };
+
+ CompileUnit(DWARFUnit &OrigUnit, unsigned ID)
+ : OrigUnit(OrigUnit), ID(ID), LowPc(UINT64_MAX), HighPc(0), RangeAlloc(),
+ Ranges(RangeAlloc) {
+ Info.resize(OrigUnit.getNumDIEs());
+ }
+
+ CompileUnit(CompileUnit &&RHS)
+ : OrigUnit(RHS.OrigUnit), Info(std::move(RHS.Info)),
+ CUDie(std::move(RHS.CUDie)), StartOffset(RHS.StartOffset),
+ 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; }
+
+ unsigned getUniqueID() const { return ID; }
+
+ DIE *getOutputUnitDIE() const { return CUDie; }
+ void setOutputUnitDIE(DIE *Die) { CUDie = Die; }
+
+ 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<PatchLocation> getUnitRangesAttribute() const {
+ return UnitRangeAttribute;
+ }
+ const FunctionIntervals &getFunctionRanges() const { return Ranges; }
+ const std::vector<PatchLocation> &getRangesAttributes() const {
+ return RangeAttributes;
+ }
+
+ const std::vector<std::pair<PatchLocation, int64_t>> &
+ getLocationAttributes() const {
+ return LocationAttributes;
+ }
+
+ /// \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 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.
+ void noteForwardReference(DIE *Die, const CompileUnit *RefUnit,
+ 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<AccelInfo> &getPubnames() const { return Pubnames; }
+ const std::vector<AccelInfo> &getPubtypes() const { return Pubtypes; }
+
+private:
+ DWARFUnit &OrigUnit;
+ unsigned ID;
+ std::vector<DIEInfo> 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 cross-cu forward refences the target DIE's
+ /// offset isn't known you emit the reference attribute.
+ std::vector<std::tuple<DIE *, const CompileUnit *, PatchLocation>>
+ 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<PatchLocation> RangeAttributes;
+ Optional<PatchLocation> 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<std::pair<PatchLocation, int64_t>> LocationAttributes;
+
+ /// \brief Accelerator entries for the unit, both for the pub*
+ /// sections and the apple* ones.
+ /// @{
+ std::vector<AccelInfo> Pubnames;
+ std::vector<AccelInfo> Pubtypes;
+ /// @}
+};
+
+uint64_t CompileUnit::computeNextUnitOffset() {
+ NextUnitOffset = StartOffset + 11 /* Header size */;
+ // The root DIE might be null, meaning that the Unit had nothing to
+ // contribute to the linked output. In that case, we will emit the
+ // unit header without any actual DIE.
+ if (CUDie)
+ NextUnitOffset += CUDie->getSize();
+ return NextUnitOffset;
+}
+
+/// \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,
+ PatchLocation Attr) {
+ ForwardDIEReferences.emplace_back(Die, RefUnit, Attr);
+}
+
+/// \brief Apply all fixups recorded by noteForwardReference().
+void CompileUnit::fixupForwardReferences() {
+ for (const auto &Ref : ForwardDIEReferences) {
+ DIE *RefDie;
+ const CompileUnit *RefUnit;
+ PatchLocation Attr;
+ std::tie(RefDie, RefUnit, Attr) = Ref;
+ Attr.set(RefDie->getOffset() + RefUnit->getStartOffset());
+ }
+}
+
+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);
+}
+
+void CompileUnit::noteRangeAttribute(const DIE &Die, PatchLocation Attr) {
+ if (Die.getTag() != dwarf::DW_TAG_compile_unit)
+ RangeAttributes.push_back(Attr);
+ else
+ UnitRangeAttribute = Attr;
+}
+
+void CompileUnit::noteLocationAttribute(PatchLocation Attr, int64_t PcOffset) {
+ LocationAttributes.emplace_back(Attr, PcOffset);
+}
+
+/// \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 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 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<std::pair<uint32_t, StringMapEntryBase *>, 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<const MapTy::MapEntryTy *>(E->getValue().second);
+ }
+
+ uint64_t getSize() { return CurrentEndOffset; }
+
+private:
+ MapTy Strings;
+ uint32_t CurrentEndOffset;
+ MapTy::MapEntryTy Sentinel, *Last;
+};
+
+/// \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<uint32_t, StringMapEntryBase *> 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<uint32_t, StringMapEntryBase *> Entry(0, nullptr);
+ auto InsertResult = Strings.insert(std::make_pair(S, Entry));
+ return InsertResult.first->getKey();
+}
+
+/// \brief The Dwarf streaming logic
+///
+/// All interactions with the MC layer that is used to build the debug
+/// information binary representation are handled in this class.
+class DwarfStreamer {
+ /// \defgroup MCObjects MC layer objects constructed by the streamer
+ /// @{
+ std::unique_ptr<MCRegisterInfo> MRI;
+ std::unique_ptr<MCAsmInfo> MAI;
+ std::unique_ptr<MCObjectFileInfo> MOFI;
+ std::unique_ptr<MCContext> MC;
+ MCAsmBackend *MAB; // Owned by MCStreamer
+ std::unique_ptr<MCInstrInfo> MII;
+ std::unique_ptr<MCSubtargetInfo> MSTI;
+ MCCodeEmitter *MCE; // Owned by MCStreamer
+ MCStreamer *MS; // Owned by AsmPrinter
+ std::unique_ptr<TargetMachine> TM;
+ std::unique_ptr<AsmPrinter> Asm;
+ /// @}
+
+ /// \brief the file we stream the linked Dwarf to.
+ std::unique_ptr<raw_fd_ostream> 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<CompileUnit::AccelInfo> &Names);
+
+public:
+ /// \brief Actually create the streamer and the ouptut file.
+ ///
+ /// This could be done directly in the constructor, but it feels
+ /// more natural to handle errors through return value.
+ bool init(Triple TheTriple, StringRef OutputFilename);
+
+ /// \brief Dump the file to the disk.
+ bool finish();
+
+ AsmPrinter &getAsmPrinter() const { return *Asm; }
+
+ /// \brief Set the current output section to debug_info and change
+ /// the MC Dwarf version to \p DwarfVersion.
+ void switchToDebugInfoSection(unsigned DwarfVersion);
+
+ /// \brief Emit the compilation unit header for \p Unit in the
+ /// debug_info section.
+ ///
+ /// As a side effect, this also switches the current Dwarf version
+ /// of the MC layer to the one of U.getOrigUnit().
+ void emitCompileUnitHeader(CompileUnit &Unit);
+
+ /// \brief Recursively emit the DIE tree rooted at \p Die.
+ void emitDIE(DIE &Die);
+
+ /// \brief Emit the abbreviation table \p Abbrevs to the
+ /// debug_abbrev section.
+ void emitAbbrevs(const std::vector<DIEAbbrev *> &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<DWARFDebugRangeList::RangeListEntry> &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(StringRef PrologueBytes, unsigned MinInstLength,
+ std::vector<DWARFDebugLine::Row> &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) {
+ std::string ErrorStr;
+ std::string TripleName;
+ StringRef Context = "dwarf streamer init";
+
+ // Get the target.
+ const Target *TheTarget =
+ TargetRegistry::lookupTarget(TripleName, TheTriple, ErrorStr);
+ if (!TheTarget)
+ return error(ErrorStr, Context);
+ TripleName = TheTriple.getTriple();
+
+ // Create all the MC Objects.
+ MRI.reset(TheTarget->createMCRegInfo(TripleName));
+ if (!MRI)
+ return error(Twine("no register info for target ") + TripleName, Context);
+
+ MAI.reset(TheTarget->createMCAsmInfo(*MRI, TripleName));
+ if (!MAI)
+ return error("no asm info for target " + TripleName, Context);
+
+ MOFI.reset(new MCObjectFileInfo);
+ MC.reset(new MCContext(MAI.get(), MRI.get(), MOFI.get()));
+ MOFI->InitMCObjectFileInfo(TheTriple, Reloc::Default, CodeModel::Default,
+ *MC);
+
+ MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, "");
+ if (!MAB)
+ return error("no asm backend for target " + TripleName, Context);
+
+ MII.reset(TheTarget->createMCInstrInfo());
+ if (!MII)
+ return error("no instr info info for target " + TripleName, Context);
+
+ MSTI.reset(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
+ if (!MSTI)
+ return error("no subtarget info for target " + TripleName, Context);
+
+ MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, *MC);
+ if (!MCE)
+ return error("no code emitter for target " + TripleName, Context);
+
+ // Create the output file.
+ std::error_code EC;
+ OutFile =
+ llvm::make_unique<raw_fd_ostream>(OutputFilename, EC, sys::fs::F_None);
+ if (EC)
+ return error(Twine(OutputFilename) + ": " + EC.message(), Context);
+
+ MS = TheTarget->createMCObjectStreamer(TheTriple, *MC, *MAB, *OutFile, MCE,
+ *MSTI, false,
+ /*DWARFMustBeAtTheEnd*/ false);
+ if (!MS)
+ return error("no object streamer for target " + TripleName, Context);
+
+ // Finally create the AsmPrinter we'll use to emit the DIEs.
+ TM.reset(TheTarget->createTargetMachine(TripleName, "", "", TargetOptions()));
+ if (!TM)
+ return error("no target machine for target " + TripleName, Context);
+
+ Asm.reset(TheTarget->createAsmPrinter(*TM, std::unique_ptr<MCStreamer>(MS)));
+ if (!Asm)
+ return error("no asm printer for target " + TripleName, Context);
+
+ RangesSectionSize = 0;
+ LocSectionSize = 0;
+ LineSectionSize = 0;
+ FrameSectionSize = 0;
+
+ return true;
+}
+
+bool DwarfStreamer::finish() {
+ MS->Finish();
+ return true;
+}
+
+/// \brief Set the current output section to debug_info and change
+/// the MC Dwarf version to \p DwarfVersion.
+void DwarfStreamer::switchToDebugInfoSection(unsigned DwarfVersion) {
+ MS->SwitchSection(MOFI->getDwarfInfoSection());
+ MC->setDwarfVersion(DwarfVersion);
+}
+
+/// \brief Emit the compilation unit header for \p Unit in the
+/// debug_info section.
+///
+/// A Dwarf scetion header is encoded as:
+/// uint32_t Unit length (omiting this field)
+/// uint16_t Version
+/// uint32_t Abbreviation table offset
+/// uint8_t Address size
+///
+/// Leading to a total of 11 bytes.
+void DwarfStreamer::emitCompileUnitHeader(CompileUnit &Unit) {
+ unsigned Version = Unit.getOrigUnit().getVersion();
+ switchToDebugInfoSection(Version);
+
+ // Emit size of content not including length itself. The size has
+ // already been computed in CompileUnit::computeOffsets(). Substract
+ // 4 to that size to account for the length field.
+ Asm->EmitInt32(Unit.getNextUnitOffset() - Unit.getStartOffset() - 4);
+ Asm->EmitInt16(Version);
+ // We share one abbreviations table across all units so it's always at the
+ // start of the section.
+ Asm->EmitInt32(0);
+ Asm->EmitInt8(Unit.getOrigUnit().getAddressByteSize());
+}
+
+/// \brief Emit the \p Abbrevs array as the shared abbreviation table
+/// for the linked Dwarf file.
+void DwarfStreamer::emitAbbrevs(const std::vector<DIEAbbrev *> &Abbrevs) {
+ MS->SwitchSection(MOFI->getDwarfAbbrevSection());
+ Asm->emitDwarfAbbrevs(Abbrevs);
+}
+
+/// \brief Recursively emit the DIE tree rooted at \p Die.
+void DwarfStreamer::emitDIE(DIE &Die) {
+ MS->SwitchSection(MOFI->getDwarfInfoSection());
+ Asm->emitDwarfDIE(Die);
+}
+
+/// \brief Emit the debug_str section stored in \p Pool.
+void DwarfStreamer::emitStrings(const NonRelocatableStringpool &Pool) {
+ Asm->OutStreamer->SwitchSection(MOFI->getDwarfStrSection());
+ for (auto *Entry = Pool.getFirstEntry(); Entry;
+ Entry = Pool.getNextEntry(Entry))
+ 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<DWARFDebugRangeList::RangeListEntry> &Entries,
+ unsigned AddressSize) {
+ MS->SwitchSection(MC->getObjectFileInfo()->getDwarfRangesSection());
+
+ // Offset each range by the right amount.
+ int64_t PcOffset = 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<std::pair<uint64_t, uint64_t>> 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(StringRef PrologueBytes,
+ unsigned MinInstLength,
+ std::vector<DWARFDebugLine::Row> &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, 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, LineDelta, AddressDelta, EncodingOS);
+ MS->EmitBytes(EncodingOS.str());
+ LineSectionSize += EncodingBuffer.size();
+ EncodingBuffer.resize(0);
+ EncodingOS.resync();
+ 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, INT64_MAX, 0, EncodingOS);
+ MS->EmitBytes(EncodingOS.str());
+ LineSectionSize += EncodingBuffer.size();
+ EncodingBuffer.resize(0);
+ EncodingOS.resync();
+ Address = -1ULL;
+ LastLine = FileNum = IsStatement = 1;
+ RowsSinceLastSequence = Column = Isa = 0;
+ }
+ }
+
+ if (RowsSinceLastSequence) {
+ MCDwarfLineAddr::Encode(*MC, INT64_MAX, 0, EncodingOS);
+ MS->EmitBytes(EncodingOS.str());
+ LineSectionSize += EncodingBuffer.size();
+ EncodingBuffer.resize(0);
+ EncodingOS.resync();
+ }
+
+ 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<CompileUnit::AccelInfo> &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
+/// driven by the selection of 'root DIEs', which are DIEs that
+/// describe variables or functions that are present in the linked
+/// binary (and thus have entries in the debug map). All the debug
+/// information that will be linked (the DIEs, but also the line
+/// tables, ranges, ...) is derived from that set of root DIEs.
+///
+/// The root DIEs are identified because they contain relocations that
+/// correspond to a debug map entry at specific places (the low_pc for
+/// a function, the location for a variable). These relocations are
+/// called ValidRelocs in the DwarfLinker and are gathered as a very
+/// first step when we start processing a DebugMapObject.
+class DwarfLinker {
+public:
+ DwarfLinker(StringRef OutputFilename, const LinkOptions &Options)
+ : OutputFilename(OutputFilename), Options(Options),
+ BinHolder(Options.Verbose), LastCIEOffset(0) {}
+
+ ~DwarfLinker() {
+ for (auto *Abbrev : Abbreviations)
+ delete Abbrev;
+ }
+
+ /// \brief Link the contents of the DebugMap.
+ bool link(const DebugMap &);
+
+private:
+ /// \brief Called at the start of a debug object link.
+ 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;
+
+ 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; }
+ };
+
+ /// \brief The valid relocations for the current DebugMapObject.
+ /// This vector is sorted by relocation offset.
+ std::vector<ValidReloc> 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,
+ const DebugMapObject &DMO, CompileUnit &CU,
+ unsigned Flags);
+
+ /// \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.
+ };
+
+ /// \brief Mark the passed DIE as well as all the ones it depends on
+ /// as kept.
+ void keepDIEAndDenpendencies(const DWARFDebugInfoEntryMinimal &DIE,
+ CompileUnit::DIEInfo &MyInfo,
+ const DebugMapObject &DMO, CompileUnit &CU,
+ unsigned Flags);
+
+ unsigned shouldKeepDIE(const DWARFDebugInfoEntryMinimal &DIE,
+ CompileUnit &Unit, CompileUnit::DIEInfo &MyInfo,
+ unsigned Flags);
+
+ unsigned shouldKeepVariableDIE(const DWARFDebugInfoEntryMinimal &DIE,
+ CompileUnit &Unit,
+ CompileUnit::DIEInfo &MyInfo, unsigned Flags);
+
+ unsigned shouldKeepSubprogramDIE(const DWARFDebugInfoEntryMinimal &DIE,
+ CompileUnit &Unit,
+ CompileUnit::DIEInfo &MyInfo,
+ unsigned Flags);
+
+ bool hasValidRelocation(uint32_t StartOffset, uint32_t EndOffset,
+ CompileUnit::DIEInfo &Info);
+ /// @}
+
+ /// \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.
+ /// \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.
+ DIE *cloneDIE(const DWARFDebugInfoEntryMinimal &InputDIE, CompileUnit &U,
+ int64_t PCOffset, uint32_t OutOffset);
+
+ typedef DWARFAbbreviationDeclaration::AttributeSpec AttributeSpec;
+
+ /// \brief 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 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), OrigHighPc(0), PCOffset(0), HasLowPc(false),
+ IsDeclaration(false) {}
+ };
+
+ /// \brief Helper for cloneDIE.
+ unsigned cloneAttribute(DIE &Die, const DWARFDebugInfoEntryMinimal &InputDIE,
+ CompileUnit &U, const DWARFFormValue &Val,
+ const AttributeSpec AttrSpec, unsigned AttrSize,
+ AttributesInfo &AttrInfo);
+
+ /// \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, CompileUnit &Unit);
+
+ /// \brief Helper for cloneDIE.
+ unsigned cloneBlockAttribute(DIE &Die, AttributeSpec AttrSpec,
+ const DWARFFormValue &Val, unsigned AttrSize);
+
+ /// \brief Helper for cloneDIE.
+ unsigned cloneAddressAttribute(DIE &Die, AttributeSpec AttrSpec,
+ const DWARFFormValue &Val,
+ const CompileUnit &Unit, AttributesInfo &Info);
+
+ /// \brief Helper for cloneDIE.
+ unsigned cloneScalarAttribute(DIE &Die,
+ const DWARFDebugInfoEntryMinimal &InputDIE,
+ CompileUnit &U, AttributeSpec AttrSpec,
+ const DWARFFormValue &Val, unsigned AttrSize,
+ AttributesInfo &Info);
+
+ /// \brief Helper for cloneDIE.
+ bool applyValidRelocs(MutableArrayRef<char> Data, uint32_t BaseOffset,
+ bool isLittleEndian);
+
+ /// \brief Assign an abbreviation number to \p Abbrev
+ void AssignAbbrev(DIEAbbrev &Abbrev);
+
+ /// \brief FoldingSet that uniques the abbreviations.
+ FoldingSet<DIEAbbrev> AbbreviationsSet;
+ /// \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<DIEAbbrev *> 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<DIELoc *> DIELocs;
+ /// \brief DIEBlock objects that need to be destructed (but not freed!).
+ std::vector<DIEBlock *> DIEBlocks;
+ /// \brief Allocator used for all the DIEValue objects.
+ BumpPtrAllocator DIEAlloc;
+ /// @}
+
+ /// \defgroup Helpers Various helper methods.
+ ///
+ /// @{
+ const DWARFDebugInfoEntryMinimal *
+ resolveDIEReference(DWARFFormValue &RefValue, const DWARFUnit &Unit,
+ const DWARFDebugInfoEntryMinimal &DIE,
+ CompileUnit *&ReferencedCU);
+
+ CompileUnit *getUnitForOffset(unsigned Offset);
+
+ bool getDIENames(const DWARFDebugInfoEntryMinimal &Die, DWARFUnit &U,
+ AttributesInfo &Info);
+
+ void reportWarning(const Twine &Warning, const DWARFUnit *Unit = nullptr,
+ const DWARFDebugInfoEntryMinimal *DIE = nullptr) const;
+
+ bool createStreamer(Triple TheTriple, StringRef OutputFilename);
+ /// @}
+
+private:
+ std::string OutputFilename;
+ LinkOptions Options;
+ BinaryHolder BinHolder;
+ std::unique_ptr<DwarfStreamer> Streamer;
+
+ /// The units of the current debug map object.
+ std::vector<CompileUnit> Units;
+
+ /// The debug map object curently 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<uint64_t, std::pair<uint64_t, int64_t>> 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<uint32_t> EmittedCIEs;
+
+ /// Offset of the last CIE that has been emitted in the output
+ /// debug_frame section.
+ uint32_t LastCIEOffset;
+};
+
+/// \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;
+}
+
+/// \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);
+
+ if ((RefCU = getUnitForOffset(RefOffset)))
+ if (const auto *RefDie = RefCU->getOrigUnit().getDIEForOffset(RefOffset))
+ return RefDie;
+
+ reportWarning("could not find referenced DIE", &Unit, &DIE);
+ return nullptr;
+}
+
+/// \brief 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 DwarfLinker::getDIENames(const DWARFDebugInfoEntryMinimal &Die,
+ DWARFUnit &U, AttributesInfo &Info) {
+ // FIXME: a bit wastefull as the first getName might return the
+ // short name.
+ if (!Info.MangledName &&
+ (Info.MangledName = Die.getName(&U, DINameKind::LinkageName)))
+ Info.MangledNameOffset = StringPool.getStringOffset(Info.MangledName);
+
+ if (!Info.Name && (Info.Name = Die.getName(&U, DINameKind::ShortName)))
+ Info.NameOffset = StringPool.getStringOffset(Info.Name);
+
+ return Info.Name || Info.MangledName;
+}
-#include "BinaryHolder.h"
-#include "DebugMap.h"
-#include "dsymutil.h"
-#include "llvm/DebugInfo/DWARFContext.h"
-#include "llvm/DebugInfo/DWARFDebugInfoEntry.h"
-#include <string>
+/// \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 {
+ StringRef Context = "<debug map>";
+ if (CurrentDebugObject)
+ Context = CurrentDebugObject->getObjectFilename();
+ warn(Warning, Context);
-namespace llvm {
-namespace dsymutil {
+ if (!Options.Verbose || !DIE)
+ return;
-namespace {
+ errs() << " in DIE:\n";
+ DIE->dump(errs(), const_cast<DWARFUnit *>(Unit), 0 /* RecurseDepth */,
+ 6 /* Indent */);
+}
-/// \brief The core of the Dwarf linking logic.
-class DwarfLinker {
-public:
- DwarfLinker(StringRef OutputFilename, bool Verbose)
- : OutputFilename(OutputFilename), Verbose(Verbose), BinHolder(Verbose) {}
+bool DwarfLinker::createStreamer(Triple TheTriple, StringRef OutputFilename) {
+ if (Options.NoOutput)
+ return true;
- /// \brief Link the contents of the DebugMap.
- bool link(const DebugMap &);
+ Streamer = llvm::make_unique<DwarfStreamer>();
+ return Streamer->init(TheTriple, OutputFilename);
+}
-private:
- std::string OutputFilename;
- bool Verbose;
- BinaryHolder BinHolder;
-};
+/// \brief Recursive helper to gather the child->parent relationships in the
+/// original compile unit.
+static void gatherDIEParents(const DWARFDebugInfoEntryMinimal *DIE,
+ unsigned ParentIdx, CompileUnit &CU) {
+ unsigned MyIdx = CU.getOrigUnit().getDIEIndex(DIE);
+ CU.getInfo(MyIdx).ParentIdx = ParentIdx;
+
+ if (DIE->hasChildren())
+ for (auto *Child = DIE->getFirstChild(); Child && !Child->isNULL();
+ Child = Child->getSibling())
+ gatherDIEParents(Child, MyIdx, CU);
+}
+
+static bool dieNeedsChildrenToBeMeaningful(uint32_t Tag) {
+ switch (Tag) {
+ default:
+ return false;
+ case dwarf::DW_TAG_subprogram:
+ case dwarf::DW_TAG_lexical_block:
+ case dwarf::DW_TAG_subroutine_type:
+ case dwarf::DW_TAG_structure_type:
+ case dwarf::DW_TAG_class_type:
+ case dwarf::DW_TAG_union_type:
+ return true;
+ }
+ llvm_unreachable("Invalid Tag");
+}
+
+void DwarfLinker::startDebugObject(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 I = DIEBlocks.begin(), E = DIEBlocks.end(); I != E; ++I)
+ (*I)->~DIEBlock();
+ for (auto I = DIELocs.begin(), E = DIELocs.end(); I != E; ++I)
+ (*I)->~DIELoc();
+
+ DIEBlocks.clear();
+ DIELocs.clear();
+ DIEAlloc.Reset();
+}
+
+/// \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) {
+ StringRef Contents;
+ Section.getContents(Contents);
+ DataExtractor Data(Contents, Obj.isLittleEndian(), 0);
+
+ for (const object::RelocationRef &Reloc : Section.relocations()) {
+ object::DataRefImpl RelocDataRef = Reloc.getRawDataRefImpl();
+ MachO::any_relocation_info MachOReloc = Obj.getRelocation(RelocDataRef);
+ unsigned RelocSize = 1 << Obj.getAnyRelocationLength(MachOReloc);
+ uint64_t Offset64 = Reloc.getOffset();
+ if ((RelocSize != 4 && RelocSize != 8)) {
+ reportWarning(" unsupported relocation in debug_info section.");
+ continue;
+ }
+ uint32_t Offset = Offset64;
+ // Mach-o uses REL relocations, the addend is at the relocation offset.
+ uint64_t Addend = Data.getUnsigned(&Offset, RelocSize);
+
+ auto Sym = Reloc.getSymbol();
+ if (Sym != Obj.symbol_end()) {
+ StringRef SymbolName;
+ if (Sym->getName(SymbolName)) {
+ reportWarning("error getting relocation symbol name.");
+ continue;
+ }
+ 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
+ // symbol in the object file, the address in the binary that is
+ // stored in the debug map doesn't need to be offseted.
+ ValidRelocs.emplace_back(Offset64, RelocSize, 0, Mapping);
+ }
+ }
+}
+
+/// \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) {
+ // Dispatch to the right handler depending on the file type.
+ if (auto *MachOObj = dyn_cast<object::MachOObjectFile>(&Obj))
+ findValidRelocsMachO(Section, *MachOObj, DMO);
+ else
+ reportWarning(Twine("unsupported object file type: ") + Obj.getFileName());
+
+ if (ValidRelocs.empty())
+ return false;
+
+ // Sort the relocations by offset. We will walk the DIEs linearly in
+ // the file, this allows us to just keep an index in the relocation
+ // array that we advance during our walk, rather than resorting to
+ // some associative container. See DwarfLinker::NextValidReloc.
+ std::sort(ValidRelocs.begin(), ValidRelocs.end());
+ return true;
+}
+
+/// \brief Look for relocations in the debug_info section that match
+/// entries in the debug map. These relocations will drive the Dwarf
+/// link by indicating which DIEs refer to symbols present in the
+/// linked binary.
+/// \returns wether there are any valid relocations in the debug info.
+bool DwarfLinker::findValidRelocsInDebugInfo(const object::ObjectFile &Obj,
+ const DebugMapObject &DMO) {
+ // Find the debug_info section.
+ for (const object::SectionRef &Section : Obj.sections()) {
+ StringRef SectionName;
+ Section.getName(SectionName);
+ SectionName = SectionName.substr(SectionName.find_first_not_of("._"));
+ if (SectionName != "debug_info")
+ continue;
+ return findValidRelocs(Section, Obj, DMO);
+ }
+ return false;
+}
+
+/// \brief Checks that there is a relocation against an actual debug
+/// map entry between \p StartOffset and \p NextOffset.
+///
+/// This function must be called with offsets in strictly ascending
+/// order because it never looks back at relocations it already 'went past'.
+/// \returns true and sets Info.InDebugMap if it is the case.
+bool DwarfLinker::hasValidRelocation(uint32_t StartOffset, uint32_t EndOffset,
+ CompileUnit::DIEInfo &Info) {
+ assert(NextValidReloc == 0 ||
+ StartOffset > ValidRelocs[NextValidReloc - 1].Offset);
+ if (NextValidReloc >= ValidRelocs.size())
+ return false;
+
+ uint64_t RelocOffset = ValidRelocs[NextValidReloc].Offset;
+
+ // We might need to skip some relocs that we didn't consider. For
+ // example the high_pc of a discarded DIE might contain a reloc that
+ // is in the list because it actually corresponds to the start of a
+ // function that is in the debug map.
+ while (RelocOffset < StartOffset && NextValidReloc < ValidRelocs.size() - 1)
+ RelocOffset = ValidRelocs[++NextValidReloc].Offset;
+
+ if (RelocOffset < StartOffset || RelocOffset >= EndOffset)
+ return false;
+
+ const auto &ValidReloc = ValidRelocs[NextValidReloc++];
+ const auto &Mapping = ValidReloc.Mapping->getValue();
+ if (Options.Verbose)
+ outs() << "Found valid debug map entry: " << ValidReloc.Mapping->getKey()
+ << " " << format("\t%016" PRIx64 " => %016" PRIx64,
+ uint64_t(Mapping.ObjectAddress),
+ uint64_t(Mapping.BinaryAddress));
+
+ Info.AddrAdjust = int64_t(Mapping.BinaryAddress) + ValidReloc.Addend -
+ Mapping.ObjectAddress;
+ Info.InDebugMap = true;
+ return true;
+}
+
+/// \brief Get the starting and ending (exclusive) offset for the
+/// attribute with index \p Idx descibed by \p Abbrev. \p Offset is
+/// supposed to point to the position of the first attribute described
+/// by \p Abbrev.
+/// \return [StartOffset, EndOffset) as a pair.
+static std::pair<uint32_t, uint32_t>
+getAttributeOffsets(const DWARFAbbreviationDeclaration *Abbrev, unsigned Idx,
+ unsigned Offset, const DWARFUnit &Unit) {
+ DataExtractor Data = Unit.getDebugInfoExtractor();
+
+ for (unsigned i = 0; i < Idx; ++i)
+ DWARFFormValue::skipValue(Abbrev->getFormByIndex(i), Data, &Offset, &Unit);
+
+ uint32_t End = Offset;
+ DWARFFormValue::skipValue(Abbrev->getFormByIndex(Idx), Data, &End, &Unit);
+
+ return std::make_pair(Offset, End);
+}
+
+/// \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) {
+ const auto *Abbrev = DIE.getAbbreviationDeclarationPtr();
+
+ // Global variables with constant value can always be kept.
+ if (!(Flags & TF_InFunctionScope) &&
+ Abbrev->findAttributeIndex(dwarf::DW_AT_const_value) != -1U) {
+ MyInfo.InDebugMap = true;
+ return Flags | TF_Keep;
+ }
+
+ uint32_t LocationIdx = Abbrev->findAttributeIndex(dwarf::DW_AT_location);
+ if (LocationIdx == -1U)
+ return Flags;
+
+ uint32_t Offset = DIE.getOffset() + getULEB128Size(Abbrev->getCode());
+ const DWARFUnit &OrigUnit = Unit.getOrigUnit();
+ uint32_t LocationOffset, LocationEndOffset;
+ std::tie(LocationOffset, LocationEndOffset) =
+ getAttributeOffsets(Abbrev, LocationIdx, Offset, OrigUnit);
+
+ // See if there is a relocation to a valid debug map entry inside
+ // this variable's location. The order is important here. We want to
+ // always check in the variable has a valid relocation, so that the
+ // DIEInfo is filled. However, we don't want a static variable in a
+ // function to force us to keep the enclosing function.
+ if (!hasValidRelocation(LocationOffset, LocationEndOffset, MyInfo) ||
+ (Flags & TF_InFunctionScope))
+ return Flags;
+
+ if (Options.Verbose)
+ DIE.dump(outs(), const_cast<DWARFUnit *>(&OrigUnit), 0, 8 /* Indent */);
+
+ return Flags | TF_Keep;
+}
+
+/// \brief Check if a function describing DIE should be kept.
+/// \returns updated TraversalFlags.
+unsigned DwarfLinker::shouldKeepSubprogramDIE(
+ const DWARFDebugInfoEntryMinimal &DIE, CompileUnit &Unit,
+ CompileUnit::DIEInfo &MyInfo, unsigned Flags) {
+ const auto *Abbrev = DIE.getAbbreviationDeclarationPtr();
+
+ Flags |= TF_InFunctionScope;
+
+ uint32_t LowPcIdx = Abbrev->findAttributeIndex(dwarf::DW_AT_low_pc);
+ if (LowPcIdx == -1U)
+ return Flags;
+
+ uint32_t Offset = DIE.getOffset() + getULEB128Size(Abbrev->getCode());
+ const DWARFUnit &OrigUnit = Unit.getOrigUnit();
+ uint32_t LowPcOffset, LowPcEndOffset;
+ std::tie(LowPcOffset, LowPcEndOffset) =
+ getAttributeOffsets(Abbrev, LowPcIdx, Offset, OrigUnit);
+
+ uint64_t LowPc =
+ 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))
+ return Flags;
+
+ if (Options.Verbose)
+ DIE.dump(outs(), const_cast<DWARFUnit *>(&OrigUnit), 0, 8 /* Indent */);
+
+ 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,
+ 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);
+ case dwarf::DW_TAG_subprogram:
+ return shouldKeepSubprogramDIE(DIE, Unit, MyInfo, Flags);
+ case dwarf::DW_TAG_module:
+ case dwarf::DW_TAG_imported_module:
+ case dwarf::DW_TAG_imported_declaration:
+ case dwarf::DW_TAG_imported_unit:
+ // We always want to keep these.
+ return Flags | TF_Keep;
+ }
+
+ return Flags;
+}
+
+/// \brief Mark the passed DIE as well as all the ones it depends on
+/// as kept.
+///
+/// This function is called by lookForDIEsToKeep on DIEs that are
+/// newly discovered to be needed in the link. It recursively calls
+/// back to lookForDIEsToKeep while adding TF_DependencyWalk to the
+/// TraversalFlags to inform it that it's not doing the primary DIE
+/// tree walk.
+void DwarfLinker::keepDIEAndDenpendencies(const DWARFDebugInfoEntryMinimal &DIE,
+ CompileUnit::DIEInfo &MyInfo,
+ const DebugMapObject &DMO,
+ CompileUnit &CU, unsigned Flags) {
+ 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);
+ 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());
+
+ // Mark all DIEs referenced through atttributes as kept.
+ for (const auto &AttrSpec : Abbrev->attributes()) {
+ DWARFFormValue Val(AttrSpec.Form);
+
+ if (!Val.isFormClass(DWARFFormValue::FC_Reference)) {
+ DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset, &Unit);
+ continue;
+ }
+
+ Val.extractValue(Data, &Offset, &Unit);
+ CompileUnit *ReferencedCU;
+ if (const auto *RefDIE = resolveDIEReference(Val, Unit, DIE, ReferencedCU))
+ lookForDIEsToKeep(*RefDIE, DMO, *ReferencedCU,
+ TF_Keep | TF_DependencyWalk);
+ }
+}
+
+/// \brief Recursively walk the \p DIE tree and look for DIEs to
+/// keep. Store that information in \p CU's DIEInfo.
+///
+/// This function is the entry point of the DIE selection
+/// algorithm. It is expected to walk the DIE tree in file order and
+/// (though the mediation of its helper) call hasValidRelocation() on
+/// each DIE that might be a 'root DIE' (See DwarfLinker class
+/// comment).
+/// While walking the dependencies of root DIEs, this function is
+/// also called, but during these dependency walks the file order is
+/// not respected. The TF_DependencyWalk flag tells us which kind of
+/// traversal we are currently doing.
+void DwarfLinker::lookForDIEsToKeep(const DWARFDebugInfoEntryMinimal &DIE,
+ const DebugMapObject &DMO, CompileUnit &CU,
+ unsigned Flags) {
+ unsigned Idx = CU.getOrigUnit().getDIEIndex(&DIE);
+ CompileUnit::DIEInfo &MyInfo = CU.getInfo(Idx);
+ bool AlreadyKept = MyInfo.Keep;
+
+ // If the Keep flag is set, we are marking a required DIE's
+ // dependencies. If our target is already marked as kept, we're all
+ // set.
+ if ((Flags & TF_DependencyWalk) && AlreadyKept)
+ return;
+
+ // We must not call shouldKeepDIE while called from keepDIEAndDenpendencies,
+ // because it would screw up the relocation finding logic.
+ if (!(Flags & TF_DependencyWalk))
+ Flags = shouldKeepDIE(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);
+
+ // 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()))
+ Flags &= ~TF_ParentWalk;
+
+ if (!DIE.hasChildren() || (Flags & TF_ParentWalk))
+ return;
+
+ for (auto *Child = DIE.getFirstChild(); Child && !Child->isNULL();
+ Child = Child->getSibling())
+ lookForDIEsToKeep(*Child, DMO, CU, Flags);
+}
+
+/// \brief Assign an abbreviation numer to \p Abbrev.
+///
+/// Our DIEs get freed after every DebugMapObject has been processed,
+/// thus the FoldingSet we use to unique DIEAbbrevs cannot refer to
+/// the instances hold by the DIEs. When we encounter an abbreviation
+/// that we don't know, we create a permanent copy of it.
+void DwarfLinker::AssignAbbrev(DIEAbbrev &Abbrev) {
+ // Check the set for priors.
+ FoldingSetNodeID ID;
+ Abbrev.Profile(ID);
+ void *InsertToken;
+ DIEAbbrev *InSet = AbbreviationsSet.FindNodeOrInsertPos(ID, InsertToken);
+
+ // If it's newly added.
+ if (InSet) {
+ // Assign existing abbreviation number.
+ Abbrev.setNumber(InSet->getNumber());
+ } else {
+ // Add to abbreviation list.
+ Abbreviations.push_back(
+ new DIEAbbrev(Abbrev.getTag(), Abbrev.hasChildren()));
+ for (const auto &Attr : Abbrev.getData())
+ Abbreviations.back()->AddAttribute(Attr.getAttribute(), Attr.getForm());
+ AbbreviationsSet.InsertNode(Abbreviations.back(), 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) {
+ // Switch everything to out of line strings.
+ const char *String = *Val.getAsCString(&U);
+ unsigned Offset = 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(
+ DIE &Die, const DWARFDebugInfoEntryMinimal &InputDIE,
+ AttributeSpec AttrSpec, unsigned AttrSize, const DWARFFormValue &Val,
+ CompileUnit &Unit) {
+ uint32_t Ref = *Val.getAsReference(&Unit.getOrigUnit());
+ 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.",
+ &Unit.getOrigUnit(), &InputDIE);
+ return 0;
+ }
+
+ unsigned Idx = RefUnit->getOrigUnit().getDIEIndex(RefDie);
+ CompileUnit::DIEInfo &RefInfo = RefUnit->getInfo(Idx);
+ if (!RefInfo.Clone) {
+ assert(Ref > InputDIE.getOffset());
+ // We haven't cloned this DIE yet. Just create an empty one and
+ // store it. It'll get really cloned when we process it.
+ RefInfo.Clone = DIE::get(DIEAlloc, dwarf::Tag(RefDie->getTag()));
+ }
+ NewRefDie = RefInfo.Clone;
+
+ if (AttrSpec.Form == dwarf::DW_FORM_ref_addr) {
+ // We cannot currently rely on a DIEEntry to emit ref_addr
+ // references, because the implementation calls back to DwarfDebug
+ // to find the unit offset. (We don't have a DwarfDebug)
+ // FIXME: we should be able to design DIEEntry reliance on
+ // DwarfDebug away.
+ uint64_t Attr;
+ if (Ref < InputDIE.getOffset()) {
+ // We must have already cloned that DIE.
+ uint32_t NewRefOffset =
+ RefUnit->getStartOffset() + NewRefDie->getOffset();
+ Attr = NewRefOffset;
+ Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
+ dwarf::DW_FORM_ref_addr, DIEInteger(Attr));
+ } else {
+ // A forward reference. Note and fixup later.
+ Attr = 0xBADDEF;
+ Unit.noteForwardReference(
+ NewRefDie, RefUnit,
+ Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
+ dwarf::DW_FORM_ref_addr, DIEInteger(Attr)));
+ }
+ return AttrSize;
+ }
+
+ 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;
+ DIELoc *Loc = nullptr;
+ DIEBlock *Block = nullptr;
+ // Just copy the block data over.
+ if (AttrSpec.Form == dwarf::DW_FORM_exprloc) {
+ Loc = new (DIEAlloc) DIELoc;
+ DIELocs.push_back(Loc);
+ } else {
+ Block = new (DIEAlloc) DIEBlock;
+ DIEBlocks.push_back(Block);
+ }
+ Attr = Loc ? static_cast<DIE *>(Loc) : static_cast<DIE *>(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<uint8_t> Bytes = *Val.getAsBlock();
+ for (auto Byte : Bytes)
+ Attr->addValue(DIEAlloc, static_cast<dwarf::Attribute>(0),
+ dwarf::DW_FORM_data1, DIEInteger(Byte));
+ // FIXME: If DIEBlock and DIELoc just reuses the Size field of
+ // the DIE class, this if could be replaced by
+ // Attr->setSize(Bytes.size()).
+ if (Streamer) {
+ if (Loc)
+ Loc->ComputeSize(&Streamer->getAsmPrinter());
+ else
+ Block->ComputeSize(&Streamer->getAsmPrinter());
+ }
+ Die.addValue(DIEAlloc, Value);
+ return AttrSize;
+}
+
+/// \brief Clone an address attribute and add it to \p Die.
+/// \returns the size of the new attribute.
+unsigned DwarfLinker::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)
+ 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<dwarf::Attribute>(AttrSpec.Attr),
+ static_cast<dwarf::Form>(AttrSpec.Form), DIEInteger(Addr));
+ return Unit.getOrigUnit().getAddressByteSize();
+}
+
+/// \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, CompileUnit &Unit,
+ AttributeSpec AttrSpec, const DWARFFormValue &Val, unsigned AttrSize,
+ AttributesInfo &Info) {
+ uint64_t Value;
+ if (AttrSpec.Attr == dwarf::DW_AT_high_pc &&
+ Die.getTag() == dwarf::DW_TAG_compile_unit) {
+ if (Unit.getLowPc() == -1ULL)
+ return 0;
+ // Dwarf >= 4 high_pc is an size, not an address.
+ Value = Unit.getHighPc() - Unit.getLowPc();
+ } else if (AttrSpec.Form == dwarf::DW_FORM_sec_offset)
+ Value = *Val.getAsSectionOffset();
+ else if (AttrSpec.Form == dwarf::DW_FORM_sdata)
+ Value = *Val.getAsSignedConstant();
+ else if (auto OptionalValue = Val.getAsUnsignedConstant())
+ Value = *OptionalValue;
+ else {
+ reportWarning("Unsupported scalar attribute form. Dropping attribute.",
+ &Unit.getOrigUnit(), &InputDIE);
+ return 0;
+ }
+ PatchLocation Patch =
+ Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
+ dwarf::Form(AttrSpec.Form), DIEInteger(Value));
+ if (AttrSpec.Attr == dwarf::DW_AT_ranges)
+ Unit.noteRangeAttribute(Die, Patch);
+ // 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, AttributesInfo &Info) {
+ const DWARFUnit &U = Unit.getOrigUnit();
+
+ switch (AttrSpec.Form) {
+ case dwarf::DW_FORM_strp:
+ case dwarf::DW_FORM_string:
+ return cloneStringAttribute(Die, AttrSpec, Val, U);
+ case dwarf::DW_FORM_ref_addr:
+ case dwarf::DW_FORM_ref1:
+ case dwarf::DW_FORM_ref2:
+ case dwarf::DW_FORM_ref4:
+ case dwarf::DW_FORM_ref8:
+ return cloneDieReferenceAttribute(Die, InputDIE, AttrSpec, AttrSize, Val,
+ Unit);
+ case dwarf::DW_FORM_block:
+ case dwarf::DW_FORM_block1:
+ case dwarf::DW_FORM_block2:
+ case dwarf::DW_FORM_block4:
+ case dwarf::DW_FORM_exprloc:
+ return cloneBlockAttribute(Die, 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:
+ case dwarf::DW_FORM_data8:
+ case dwarf::DW_FORM_udata:
+ case dwarf::DW_FORM_sdata:
+ case dwarf::DW_FORM_sec_offset:
+ case dwarf::DW_FORM_flag:
+ case dwarf::DW_FORM_flag_present:
+ return cloneScalarAttribute(Die, InputDIE, Unit, AttrSpec, Val, AttrSize,
+ Info);
+ default:
+ reportWarning("Unsupported attribute form in cloneAttribute. Dropping.", &U,
+ &InputDIE);
+ }
+
+ return 0;
+}
+
+/// \brief Apply the valid relocations found by findValidRelocs() to
+/// the buffer \p Data, taking into account that Data is at \p BaseOffset
+/// in the debug_info section.
+///
+/// Like for findValidRelocs(), this function must be called with
+/// monotonic \p BaseOffset values.
+///
+/// \returns wether any reloc has been applied.
+bool DwarfLinker::applyValidRelocs(MutableArrayRef<char> Data,
+ uint32_t BaseOffset, bool isLittleEndian) {
+ assert((NextValidReloc == 0 ||
+ BaseOffset > ValidRelocs[NextValidReloc - 1].Offset) &&
+ "BaseOffset should only be increasing.");
+ if (NextValidReloc >= ValidRelocs.size())
+ return false;
+
+ // Skip relocs that haven't been applied.
+ while (NextValidReloc < ValidRelocs.size() &&
+ ValidRelocs[NextValidReloc].Offset < BaseOffset)
+ ++NextValidReloc;
+
+ bool Applied = false;
+ uint64_t EndOffset = BaseOffset + Data.size();
+ while (NextValidReloc < ValidRelocs.size() &&
+ ValidRelocs[NextValidReloc].Offset >= BaseOffset &&
+ ValidRelocs[NextValidReloc].Offset < EndOffset) {
+ const auto &ValidReloc = ValidRelocs[NextValidReloc++];
+ assert(ValidReloc.Offset - BaseOffset < Data.size());
+ assert(ValidReloc.Offset - BaseOffset + ValidReloc.Size <= Data.size());
+ char Buf[8];
+ uint64_t Value = ValidReloc.Mapping->getValue().BinaryAddress;
+ Value += ValidReloc.Addend;
+ for (unsigned i = 0; i != ValidReloc.Size; ++i) {
+ unsigned Index = isLittleEndian ? i : (ValidReloc.Size - i - 1);
+ Buf[i] = uint8_t(Value >> (Index * 8));
+ }
+ assert(ValidReloc.Size <= sizeof(Buf));
+ memcpy(&Data[ValidReloc.Offset - BaseOffset], Buf, ValidReloc.Size);
+ Applied = true;
+ }
+
+ return Applied;
+}
+
+static bool 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;
+}
+
+/// \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, int64_t PCOffset,
+ uint32_t OutOffset) {
+ DWARFUnit &U = Unit.getOrigUnit();
+ unsigned Idx = U.getDIEIndex(&InputDIE);
+ CompileUnit::DIEInfo &Info = Unit.getInfo(Idx);
+
+ // Should the DIE appear in the output?
+ if (!Unit.getInfo(Idx).Keep)
+ return nullptr;
+
+ uint32_t Offset = InputDIE.getOffset();
+ // The DIE might have been already created by a forward reference
+ // (see cloneDieReferenceAttribute()).
+ DIE *Die = Info.Clone;
+ if (!Die)
+ Die = Info.Clone = DIE::get(DIEAlloc, dwarf::Tag(InputDIE.getTag()));
+ assert(Die->getTag() == InputDIE.getTag());
+ Die->setOffset(OutOffset);
+
+ // Extract and clone every attribute.
+ DataExtractor Data = U.getDebugInfoExtractor();
+ uint32_t NextOffset = U.getDIEAtIndex(Idx + 1)->getOffset();
+ 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
+ // doing the copy unconditionally, and it makes the code simpler.
+ SmallString<40> DIECopy(Data.getData().substr(Offset, NextOffset - Offset));
+ Data = DataExtractor(DIECopy, Data.isLittleEndian(), Data.getAddressSize());
+ // Modify the copy with relocated addresses.
+ if (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);
+ }
+
+ // Reset the Offset to 0 as we will be working on the local copy of
+ // the data.
+ Offset = 0;
+
+ const auto *Abbrev = InputDIE.getAbbreviationDeclarationPtr();
+ Offset += getULEB128Size(Abbrev->getCode());
+
+ // We are entering a subprogram. Get and propagate the PCOffset.
+ if (Die->getTag() == dwarf::DW_TAG_subprogram)
+ PCOffset = Info.AddrAdjust;
+ AttrInfo.PCOffset = PCOffset;
+
+ for (const auto &AttrSpec : Abbrev->attributes()) {
+ DWARFFormValue Val(AttrSpec.Form);
+ uint32_t AttrSize = Offset;
+ Val.extractValue(Data, &Offset, &U);
+ AttrSize = Offset - 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);
+ }
+
+ DIEAbbrev NewAbbrev = Die->generateAbbrev();
+ // 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())
+ NewAbbrev.setChildrenFlag(dwarf::DW_CHILDREN_yes);
+ // Assign a permanent abbrev number
+ AssignAbbrev(NewAbbrev);
+ Die->setAbbrevNumber(NewAbbrev.getNumber());
+
+ // Add the size of the abbreviation number to the output offset.
+ OutOffset += getULEB128Size(Die->getAbbrevNumber());
+
+ if (!Abbrev->hasChildren()) {
+ // Update our size.
+ Die->setSize(OutOffset - Die->getOffset());
+ return Die;
+ }
+
+ // Recursively clone children.
+ for (auto *Child = InputDIE.getFirstChild(); Child && !Child->isNULL();
+ Child = Child->getSibling()) {
+ if (DIE *Clone = cloneDIE(*Child, Unit, PCOffset, OutOffset)) {
+ Die->addChild(Clone);
+ OutOffset = Clone->getOffset() + Clone->getSize();
+ }
+ }
+
+ // Account for the end of children marker.
+ OutOffset += sizeof(int8_t);
+ // Update our size.
+ Die->setSize(OutOffset - Die->getOffset());
+ return Die;
+}
+
+/// \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();
+ const DWARFDebugRangeList::RangeListEntry &First = Entries.front();
+
+ if (CurrRange == InvalidRange || First.StartAddress < CurrRange.start() ||
+ First.StartAddress >= 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<bool>(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<DWARFDebugLine::Row> &Seq,
+ std::vector<DWARFDebugLine::Row> &Rows) {
+ if (Seq.empty())
+ return;
+
+ if (!Rows.empty() && Rows.back().Address < Seq.front().Address) {
+ Rows.insert(Rows.end(), Seq.begin(), Seq.end());
+ Seq.clear();
+ return;
+ }
+
+ auto InsertPoint = std::lower_bound(
+ Rows.begin(), Rows.end(), Seq.front(),
+ [](const DWARFDebugLine::Row &LHS, const DWARFDebugLine::Row &RHS) {
+ return LHS.Address < RHS.Address;
+ });
+
+ // FIXME: this only removes the unneeded end_sequence if the
+ // sequences have been inserted in order. using a global sort like
+ // described in patchLineTableForUnit() and delaying the end_sequene
+ // elimination to emitLineTableForUnit() we can get rid of all of them.
+ if (InsertPoint != Rows.end() &&
+ InsertPoint->Address == Seq.front().Address && InsertPoint->EndSequence) {
+ *InsertPoint = Seq.front();
+ Rows.insert(InsertPoint + 1, Seq.begin() + 1, Seq.end());
+ } else {
+ Rows.insert(InsertPoint, Seq.begin(), Seq.end());
+ }
+
+ Seq.clear();
+}
+
+static void patchStmtList(DIE &Die, DIEInteger Offset) {
+ for (auto &V : Die.values())
+ if (V.getAttribute() == dwarf::DW_AT_stmt_list) {
+ V = DIEValue(V.getAttribute(), V.getForm(), Offset);
+ return;
+ }
+
+ llvm_unreachable("Didn't find DW_AT_stmt_list in cloned DIE!");
+}
+
+/// \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<DWARFDebugLine::Row> NewRows;
+ NewRows.reserve(LineTable.Rows.size());
+
+ // Current sequence of rows being extracted, before being inserted
+ // in NewRows.
+ std::vector<DWARFDebugLine::Row> Seq;
+ const auto &FunctionRanges = Unit.getFunctionRanges();
+ auto InvalidRange = FunctionRanges.end(), CurrRange = InvalidRange;
+
+ // FIXME: This logic is meant to generate exactly the same output as
+ // Darwin's classic 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.
+ Seq.emplace_back(Seq.back());
+ Seq.back().Address = StopAddress;
+ Seq.back().EndSequence = 1;
+ Seq.back().PrologueEnd = 0;
+ Seq.back().BasicBlock = 0;
+ Seq.back().EpilogueBegin = 0;
+ 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.LineBase != -5 || LineTable.Prologue.LineRange != 14 ||
+ LineTable.Prologue.OpcodeBase != 13)
+ reportWarning("line table paramters mismatch. Cannot emit.");
+ else
+ Streamer->emitLineTableForUnit(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<uint32_t, StringRef> LocalCIES;
+
+ while (Data.isValidOffset(InputOffset)) {
+ uint32_t EntryOffset = InputOffset;
+ uint32_t InitialLength = Data.getU32(&InputOffset);
+ if (InitialLength == 0xFFFFFFFF)
+ return reportWarning("Dwarf64 bits no supported");
+
+ 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;
+ }
+}
bool DwarfLinker::link(const DebugMap &Map) {
return false;
}
+ if (!createStreamer(Map.getTriple(), OutputFilename))
+ return false;
+
+ // Size of the DIEs (and headers) generated for the linked output.
+ uint64_t OutputDebugInfoSize = 0;
+ // A unique ID that identifies each compile unit.
+ unsigned UnitID = 0;
for (const auto &Obj : Map.objects()) {
- if (Verbose)
+ 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()) {
- errs() << Obj->getObjectFilename() << ": " << EC.message() << "\n";
+ reportWarning(Twine(Obj->getObjectFilename()) + ": " + EC.message());
+ continue;
+ }
+
+ // Look for relocations that correspond to debug map entries.
+ if (!findValidRelocsInDebugInfo(*ErrOrObj, *Obj)) {
+ if (Options.Verbose)
+ outs() << "No valid relocations found. Skipping.\n";
continue;
}
+ // Setup access to the debug info.
DWARFContextInMemory DwarfContext(*ErrOrObj);
+ 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.
for (const auto &CU : DwarfContext.compile_units()) {
- auto *CUDie = CU->getCompileUnitDIE(false);
- if (Verbose) {
+ auto *CUDie = CU->getUnitDIE(false);
+ if (Options.Verbose) {
outs() << "Input compilation unit:";
CUDie->dump(outs(), CU.get(), 0);
}
+ Units.emplace_back(*CU, UnitID++);
+ gatherDIEParents(CUDie, 0, Units.back());
}
+
+ // 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().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().getUnitDIE();
+ CurrentUnit.setStartOffset(OutputDebugInfoSize);
+ DIE *OutputDIE = cloneDIE(*InputDIE, CurrentUnit, 0 /* PCOffset */,
+ 11 /* Unit Header size */);
+ CurrentUnit.setOutputUnitDIE(OutputDIE);
+ OutputDebugInfoSize = CurrentUnit.computeNextUnitOffset();
+ if (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.
+ patchLineTableForUnit(CurrentUnit, DwarfContext);
+ if (!OutputDIE)
+ continue;
+ patchRangesForUnit(CurrentUnit, DwarfContext);
+ Streamer->emitLocationsForUnit(CurrentUnit, DwarfContext);
+ emitAcceleratorEntriesForUnit(CurrentUnit);
+ }
+
+ // Emit all the compile unit's debug information.
+ if (!ValidRelocs.empty() && !Options.NoOutput)
+ for (auto &CurrentUnit : Units) {
+ generateUnitRanges(CurrentUnit);
+ CurrentUnit.fixupForwardReferences();
+ Streamer->emitCompileUnitHeader(CurrentUnit);
+ if (!CurrentUnit.getOutputUnitDIE())
+ continue;
+ Streamer->emitDIE(*CurrentUnit.getOutputUnitDIE());
+ }
+
+ if (!ValidRelocs.empty() && !Options.NoOutput && !Units.empty())
+ patchFrameInfoForObject(*Obj, DwarfContext,
+ Units[0].getOrigUnit().getAddressByteSize());
+
+ // Clean-up before starting working on the next object.
+ endDebugObject();
}
- return true;
+ // Emit everything that's global.
+ if (!Options.NoOutput) {
+ Streamer->emitAbbrevs(Abbreviations);
+ Streamer->emitStrings(StringPool);
+ }
+
+ return Options.NoOutput ? true : Streamer->finish();
}
}
-bool linkDwarf(StringRef OutputFilename, const DebugMap &DM, bool Verbose) {
- DwarfLinker Linker(OutputFilename, Verbose);
+bool linkDwarf(StringRef OutputFilename, const DebugMap &DM,
+ const LinkOptions &Options) {
+ DwarfLinker Linker(OutputFilename, Options);
return Linker.link(DM);
}
}
projects / oota-llvm.git / blobdiff