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//===- DWARFUnit.h ----------------------------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugRnglists.h"
#include "llvm/DebugInfo/DWARF/DWARFDie.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
#include "llvm/DebugInfo/DWARF/DWARFSection.h"
#include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
#include "llvm/Support/DataExtractor.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <map>
#include <memory>
#include <utility>
#include <vector>
namespace llvm {
class DWARFAbbreviationDeclarationSet;
class DWARFContext;
class DWARFDebugAbbrev;
class DWARFUnit;
/// Base class describing the header of any kind of "unit." Some information
/// is specific to certain unit types. We separate this class out so we can
/// parse the header before deciding what specific kind of unit to construct.
class DWARFUnitHeader {
// Offset within section.
uint32_t Offset = 0;
// Version, address size, and DWARF format.
dwarf::FormParams FormParams;
uint32_t Length = 0;
uint64_t AbbrOffset = 0;
// For DWO units only.
const DWARFUnitIndex::Entry *IndexEntry = nullptr;
// For type units only.
uint64_t TypeHash = 0;
uint32_t TypeOffset = 0;
// For v5 split or skeleton compile units only.
Optional<uint64_t> DWOId;
// Unit type as parsed, or derived from the section kind.
uint8_t UnitType = 0;
// Size as parsed. uint8_t for compactness.
uint8_t Size = 0;
/// Parse a unit header from \p debug_info starting at \p offset_ptr.
bool extract(DWARFContext &Context, const DWARFDataExtractor &debug_info,
uint32_t *offset_ptr, DWARFSectionKind Kind = DW_SECT_INFO,
const DWARFUnitIndex *Index = nullptr,
const DWARFUnitIndex::Entry *Entry = nullptr);
uint32_t getOffset() const { return Offset; }
const dwarf::FormParams &getFormParams() const { return FormParams; }
uint16_t getVersion() const { return FormParams.Version; }
dwarf::DwarfFormat getFormat() const { return FormParams.Format; }
uint8_t getAddressByteSize() const { return FormParams.AddrSize; }
uint8_t getRefAddrByteSize() const { return FormParams.getRefAddrByteSize(); }
uint8_t getDwarfOffsetByteSize() const {
return FormParams.getDwarfOffsetByteSize();
uint32_t getLength() const { return Length; }
uint64_t getAbbrOffset() const { return AbbrOffset; }
Optional<uint64_t> getDWOId() const { return DWOId; }
void setDWOId(uint64_t Id) {
assert((!DWOId || *DWOId == Id) && "setting DWOId to a different value");
DWOId = Id;
const DWARFUnitIndex::Entry *getIndexEntry() const { return IndexEntry; }
uint64_t getTypeHash() const { return TypeHash; }
uint32_t getTypeOffset() const { return TypeOffset; }
uint8_t getUnitType() const { return UnitType; }
bool isTypeUnit() const {
return UnitType == dwarf::DW_UT_type || UnitType == dwarf::DW_UT_split_type;
uint8_t getSize() const { return Size; }
// FIXME: Support DWARF64.
uint32_t getNextUnitOffset() const { return Offset + Length + 4; }
const DWARFUnitIndex &getDWARFUnitIndex(DWARFContext &Context,
DWARFSectionKind Kind);
/// Describe a collection of units. Intended to hold all units either from
/// .debug_info and .debug_types, or from .debug_info.dwo and .debug_types.dwo.
class DWARFUnitVector final : public SmallVector<std::unique_ptr<DWARFUnit>, 1> {
std::function<std::unique_ptr<DWARFUnit>(uint32_t, DWARFSectionKind,
const DWARFSection *,
const DWARFUnitIndex::Entry *)>
int NumInfoUnits = -1;
using UnitVector = SmallVectorImpl<std::unique_ptr<DWARFUnit>>;
using iterator = typename UnitVector::iterator;
using iterator_range = llvm::iterator_range<typename UnitVector::iterator>;
DWARFUnit *getUnitForOffset(uint32_t Offset) const;
DWARFUnit *getUnitForIndexEntry(const DWARFUnitIndex::Entry &E);
/// Read units from a .debug_info or .debug_types section. Calls made
/// before finishedInfoUnits() are assumed to be for .debug_info sections,
/// calls after finishedInfoUnits() are for .debug_types sections. Caller
/// must not mix calls to addUnitsForSection and addUnitsForDWOSection.
void addUnitsForSection(DWARFContext &C, const DWARFSection &Section,
DWARFSectionKind SectionKind);
/// Read units from a .debug_info.dwo or .debug_types.dwo section. Calls
/// made before finishedInfoUnits() are assumed to be for .debug_info.dwo
/// sections, calls after finishedInfoUnits() are for .debug_types.dwo
/// sections. Caller must not mix calls to addUnitsForSection and
/// addUnitsForDWOSection.
void addUnitsForDWOSection(DWARFContext &C, const DWARFSection &DWOSection,
DWARFSectionKind SectionKind, bool Lazy = false);
/// Add an existing DWARFUnit to this UnitVector. This is used by the DWARF
/// verifier to process unit separately.
DWARFUnit *addUnit(std::unique_ptr<DWARFUnit> Unit);
/// Returns number of all units held by this instance.
unsigned getNumUnits() const { return size(); }
/// Returns number of units from all .debug_info[.dwo] sections.
unsigned getNumInfoUnits() const {
return NumInfoUnits == -1 ? size() : NumInfoUnits;
/// Returns number of units from all .debug_types[.dwo] sections.
unsigned getNumTypesUnits() const { return size() - NumInfoUnits; }
/// Indicate that parsing .debug_info[.dwo] is done, and remaining units
/// will be from .debug_types[.dwo].
void finishedInfoUnits() { NumInfoUnits = size(); }
void addUnitsImpl(DWARFContext &Context, const DWARFObject &Obj,
const DWARFSection &Section, const DWARFDebugAbbrev *DA,
const DWARFSection *RS, const DWARFSection *LocSection,
StringRef SS, const DWARFSection &SOS,
const DWARFSection *AOS, const DWARFSection &LS, bool LE,
bool IsDWO, bool Lazy, DWARFSectionKind SectionKind);
/// Represents base address of the CU.
/// Represents a unit's contribution to the string offsets table.
struct StrOffsetsContributionDescriptor {
uint64_t Base = 0;
/// The contribution size not including the header.
uint64_t Size = 0;
/// Format and version.
dwarf::FormParams FormParams = {0, 0, dwarf::DwarfFormat::DWARF32};
StrOffsetsContributionDescriptor(uint64_t Base, uint64_t Size,
uint8_t Version, dwarf::DwarfFormat Format)
: Base(Base), Size(Size), FormParams({Version, 0, Format}) {}
uint8_t getVersion() const { return FormParams.Version; }
dwarf::DwarfFormat getFormat() const { return FormParams.Format; }
uint8_t getDwarfOffsetByteSize() const {
return FormParams.getDwarfOffsetByteSize();
/// Determine whether a contribution to the string offsets table is
/// consistent with the relevant section size and that its length is
/// a multiple of the size of one of its entries.
validateContributionSize(DWARFDataExtractor &DA);
class DWARFUnit {
DWARFContext &Context;
/// Section containing this DWARFUnit.
const DWARFSection &InfoSection;
DWARFUnitHeader Header;
const DWARFDebugAbbrev *Abbrev;
const DWARFSection *RangeSection;
uint32_t RangeSectionBase;
/// We either keep track of the location list section or its data, depending
/// on whether we are handling a split DWARF section or not.
union {
const DWARFSection *LocSection;
StringRef LocSectionData;
const DWARFSection &LineSection;
StringRef StringSection;
const DWARFSection &StringOffsetSection;
const DWARFSection *AddrOffsetSection;
uint32_t AddrOffsetSectionBase = 0;
bool isLittleEndian;
bool IsDWO;
const DWARFUnitVector &UnitVector;
/// Start, length, and DWARF format of the unit's contribution to the string
/// offsets table (DWARF v5).
Optional<StrOffsetsContributionDescriptor> StringOffsetsTableContribution;
/// A table of range lists (DWARF v5 and later).
Optional<DWARFDebugRnglistTable> RngListTable;
mutable const DWARFAbbreviationDeclarationSet *Abbrevs;
llvm::Optional<SectionedAddress> BaseAddr;
/// The compile unit debug information entry items.
std::vector<DWARFDebugInfoEntry> DieArray;
/// Map from range's start address to end address and corresponding DIE.
/// IntervalMap does not support range removal, as a result, we use the
/// std::map::upper_bound for address range lookup.
std::map<uint64_t, std::pair<uint64_t, DWARFDie>> AddrDieMap;
using die_iterator_range =
std::shared_ptr<DWARFUnit> DWO;
uint32_t getDIEIndex(const DWARFDebugInfoEntry *Die) {
auto First =;
assert(Die >= First && Die < First + DieArray.size());
return Die - First;
const DWARFUnitHeader &getHeader() const { return Header; }
/// Size in bytes of the parsed unit header.
uint32_t getHeaderSize() const { return Header.getSize(); }
/// Find the unit's contribution to the string offsets table and determine its
/// length and form. The given offset is expected to be derived from the unit
/// DIE's DW_AT_str_offsets_base attribute.
determineStringOffsetsTableContribution(DWARFDataExtractor &DA);
/// Find the unit's contribution to the string offsets table and determine its
/// length and form. The given offset is expected to be 0 in a dwo file or,
/// in a dwp file, the start of the unit's contribution to the string offsets
/// table section (as determined by the index table).
determineStringOffsetsTableContributionDWO(DWARFDataExtractor &DA);
DWARFUnit(DWARFContext &Context, const DWARFSection &Section,
const DWARFUnitHeader &Header, const DWARFDebugAbbrev *DA,
const DWARFSection *RS, const DWARFSection *LocSection,
StringRef SS, const DWARFSection &SOS, const DWARFSection *AOS,
const DWARFSection &LS, bool LE, bool IsDWO,
const DWARFUnitVector &UnitVector);
virtual ~DWARFUnit();
bool isDWOUnit() const { return IsDWO; }
DWARFContext& getContext() const { return Context; }
const DWARFSection &getInfoSection() const { return InfoSection; }
const DWARFSection *getLocSection() const { return LocSection; }
StringRef getLocSectionData() const { return LocSectionData; }
uint32_t getOffset() const { return Header.getOffset(); }
const dwarf::FormParams &getFormParams() const {
return Header.getFormParams();
uint16_t getVersion() const { return Header.getVersion(); }
uint8_t getAddressByteSize() const { return Header.getAddressByteSize(); }
uint8_t getRefAddrByteSize() const { return Header.getRefAddrByteSize(); }
uint8_t getDwarfOffsetByteSize() const {
return Header.getDwarfOffsetByteSize();
uint32_t getLength() const { return Header.getLength(); }
uint8_t getUnitType() const { return Header.getUnitType(); }
bool isTypeUnit() const { return Header.isTypeUnit(); }
uint32_t getNextUnitOffset() const { return Header.getNextUnitOffset(); }
const DWARFSection &getLineSection() const { return LineSection; }
StringRef getStringSection() const { return StringSection; }
const DWARFSection &getStringOffsetSection() const {
return StringOffsetSection;
void setAddrOffsetSection(const DWARFSection *AOS, uint32_t Base) {
AddrOffsetSection = AOS;
AddrOffsetSectionBase = Base;
/// Recursively update address to Die map.
void updateAddressDieMap(DWARFDie Die);
void setRangesSection(const DWARFSection *RS, uint32_t Base) {
RangeSection = RS;
RangeSectionBase = Base;
Optional<SectionedAddress> getAddrOffsetSectionItem(uint32_t Index) const;
Optional<uint64_t> getStringOffsetSectionItem(uint32_t Index) const;
DWARFDataExtractor getDebugInfoExtractor() const;
DataExtractor getStringExtractor() const {
return DataExtractor(StringSection, false, 0);
/// Extract the range list referenced by this compile unit from the
/// .debug_ranges section. If the extraction is unsuccessful, an error
/// is returned. Successful extraction requires that the compile unit
/// has already been extracted.
Error extractRangeList(uint32_t RangeListOffset,
DWARFDebugRangeList &RangeList) const;
void clear();
const Optional<StrOffsetsContributionDescriptor> &
getStringOffsetsTableContribution() const {
return StringOffsetsTableContribution;
uint8_t getDwarfStringOffsetsByteSize() const {
return StringOffsetsTableContribution->getDwarfOffsetByteSize();
uint64_t getStringOffsetsBase() const {
return StringOffsetsTableContribution->Base;
const DWARFAbbreviationDeclarationSet *getAbbreviations() const;
static bool isMatchingUnitTypeAndTag(uint8_t UnitType, dwarf::Tag Tag) {
switch (UnitType) {
case dwarf::DW_UT_compile:
return Tag == dwarf::DW_TAG_compile_unit;
case dwarf::DW_UT_type:
return Tag == dwarf::DW_TAG_type_unit;
case dwarf::DW_UT_partial:
return Tag == dwarf::DW_TAG_partial_unit;
case dwarf::DW_UT_skeleton:
return Tag == dwarf::DW_TAG_skeleton_unit;
case dwarf::DW_UT_split_compile:
case dwarf::DW_UT_split_type:
return dwarf::isUnitType(Tag);
return false;
/// Return the number of bytes for the header of a unit of
/// UnitType type.
/// This function must be called with a valid unit type which in
/// DWARF5 is defined as one of the following six types.
static uint32_t getDWARF5HeaderSize(uint8_t UnitType) {
switch (UnitType) {
case dwarf::DW_UT_compile:
case dwarf::DW_UT_partial:
return 12;
case dwarf::DW_UT_skeleton:
case dwarf::DW_UT_split_compile:
return 20;
case dwarf::DW_UT_type:
case dwarf::DW_UT_split_type:
return 24;
llvm_unreachable("Invalid UnitType.");
llvm::Optional<SectionedAddress> getBaseAddress();
DWARFDie getUnitDIE(bool ExtractUnitDIEOnly = true) {
if (DieArray.empty())
return DWARFDie();
return DWARFDie(this, &DieArray[0]);
const char *getCompilationDir();
Optional<uint64_t> getDWOId() {
extractDIEsIfNeeded(/*CUDieOnly*/ true);
return getHeader().getDWOId();
void setDWOId(uint64_t NewID) { Header.setDWOId(NewID); }
/// Return a vector of address ranges resulting from a (possibly encoded)
/// range list starting at a given offset in the appropriate ranges section.
Expected<DWARFAddressRangesVector> findRnglistFromOffset(uint32_t Offset);
/// Return a vector of address ranges retrieved from an encoded range
/// list whose offset is found via a table lookup given an index (DWARF v5
/// and later).
Expected<DWARFAddressRangesVector> findRnglistFromIndex(uint32_t Index);
/// Return a rangelist's offset based on an index. The index designates
/// an entry in the rangelist table's offset array and is supplied by
/// DW_FORM_rnglistx.
Optional<uint32_t> getRnglistOffset(uint32_t Index) {
if (RngListTable)
return RngListTable->getOffsetEntry(Index);
return None;
Expected<DWARFAddressRangesVector> collectAddressRanges();
/// Returns subprogram DIE with address range encompassing the provided
/// address. The pointer is alive as long as parsed compile unit DIEs are not
/// cleared.
DWARFDie getSubroutineForAddress(uint64_t Address);
/// getInlinedChainForAddress - fetches inlined chain for a given address.
/// Returns empty chain if there is no subprogram containing address. The
/// chain is valid as long as parsed compile unit DIEs are not cleared.
void getInlinedChainForAddress(uint64_t Address,
SmallVectorImpl<DWARFDie> &InlinedChain);
/// Return the DWARFUnitVector containing this unit.
const DWARFUnitVector &getUnitVector() const { return UnitVector; }
/// Returns the number of DIEs in the unit. Parses the unit
/// if necessary.
unsigned getNumDIEs() {
return DieArray.size();
/// Return the index of a DIE inside the unit's DIE vector.
/// It is illegal to call this method with a DIE that hasn't be
/// created by this unit. In other word, it's illegal to call this
/// method on a DIE that isn't accessible by following
/// children/sibling links starting from this unit's getUnitDIE().
uint32_t getDIEIndex(const DWARFDie &D) {
return getDIEIndex(D.getDebugInfoEntry());
/// Return the DIE object at the given index.
DWARFDie getDIEAtIndex(unsigned Index) {
assert(Index < DieArray.size());
return DWARFDie(this, &DieArray[Index]);
DWARFDie getParent(const DWARFDebugInfoEntry *Die);
DWARFDie getSibling(const DWARFDebugInfoEntry *Die);
DWARFDie getPreviousSibling(const DWARFDebugInfoEntry *Die);
DWARFDie getFirstChild(const DWARFDebugInfoEntry *Die);
DWARFDie getLastChild(const DWARFDebugInfoEntry *Die);
/// Return the DIE object for a given offset inside the
/// unit's DIE vector.
/// The unit needs to have its DIEs extracted for this method to work.
DWARFDie getDIEForOffset(uint32_t Offset) {
auto it = std::lower_bound(
DieArray.begin(), DieArray.end(), Offset,
[](const DWARFDebugInfoEntry &LHS, uint32_t Offset) {
return LHS.getOffset() < Offset;
if (it != DieArray.end() && it->getOffset() == Offset)
return DWARFDie(this, &*it);
return DWARFDie();
uint32_t getLineTableOffset() const {
if (auto IndexEntry = Header.getIndexEntry())
if (const auto *Contrib = IndexEntry->getOffset(DW_SECT_LINE))
return Contrib->Offset;
return 0;
die_iterator_range dies() {
return die_iterator_range(DieArray.begin(), DieArray.end());
virtual void dump(raw_ostream &OS, DIDumpOptions DumpOpts) = 0;
/// Size in bytes of the .debug_info data associated with this compile unit.
size_t getDebugInfoSize() const {
return Header.getLength() + 4 - getHeaderSize();
/// extractDIEsIfNeeded - Parses a compile unit and indexes its DIEs if it
/// hasn't already been done. Returns the number of DIEs parsed at this call.
size_t extractDIEsIfNeeded(bool CUDieOnly);
/// extractDIEsToVector - Appends all parsed DIEs to a vector.
void extractDIEsToVector(bool AppendCUDie, bool AppendNonCUDIEs,
std::vector<DWARFDebugInfoEntry> &DIEs) const;
/// clearDIEs - Clear parsed DIEs to keep memory usage low.
void clearDIEs(bool KeepCUDie);
/// parseDWO - Parses .dwo file for current compile unit. Returns true if
/// it was actually constructed.
bool parseDWO();
} // end namespace llvm