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//===- tools/dsymutil/DwarfLinkerForBinary.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 "BinaryHolder.h"
#include "DebugMap.h"
#include "LinkUtils.h"
#include "llvm/DWARFLinker/DWARFLinker.h"
#include "llvm/DWARFLinker/DWARFLinkerCompileUnit.h"
#include "llvm/DWARFLinker/DWARFLinkerDeclContext.h"
#include "llvm/DWARFLinker/DWARFStreamer.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/Remarks/RemarkFormat.h"
#include "llvm/Remarks/RemarkLinker.h"
namespace llvm {
namespace dsymutil {
/// The core of the Dsymutil Dwarf linking logic.
/// The link of the dwarf information from the object files will be
/// driven by DWARFLinker. DwarfLinkerForBinary reads DebugMap objects
/// and pass information to the DWARFLinker. DWARFLinker
/// optimizes DWARF taking into account valid relocations.
/// Finally, optimized DWARF is passed to DwarfLinkerForBinary through
/// DWARFEmitter interface.
class DwarfLinkerForBinary {
DwarfLinkerForBinary(raw_fd_ostream &OutFile, BinaryHolder &BinHolder,
LinkOptions Options)
: OutFile(OutFile), BinHolder(BinHolder), Options(std::move(Options)) {}
/// Link the contents of the DebugMap.
bool link(const DebugMap &);
void reportWarning(const Twine &Warning, StringRef Context,
const DWARFDie *DIE = nullptr) const;
/// Flags passed to DwarfLinker::lookForDIEsToKeep
enum TraversalFlags {
TF_Keep = 1 << 0, ///< Mark the traversed DIEs as kept.
TF_InFunctionScope = 1 << 1, ///< Current scope is a function scope.
TF_DependencyWalk = 1 << 2, ///< Walking the dependencies of a kept DIE.
TF_ParentWalk = 1 << 3, ///< Walking up the parents of a kept DIE.
TF_ODR = 1 << 4, ///< Use the ODR while keeping dependents.
TF_SkipPC = 1 << 5, ///< Skip all location attributes.
/// Keeps track of relocations.
class AddressManager : public AddressesMap {
struct ValidReloc {
uint64_t Offset;
uint32_t Size;
uint64_t Addend;
const DebugMapObject::DebugMapEntry *Mapping;
ValidReloc(uint64_t Offset, uint32_t Size, uint64_t Addend,
const DebugMapObject::DebugMapEntry *Mapping)
: Offset(Offset), Size(Size), Addend(Addend), Mapping(Mapping) {}
bool operator<(const ValidReloc &RHS) const {
return Offset < RHS.Offset;
bool operator<(uint64_t RHS) const { return Offset < RHS; }
const DwarfLinkerForBinary &Linker;
/// The valid relocations for the current DebugMapObject.
/// This vector is sorted by relocation offset.
/// {
std::vector<ValidReloc> ValidDebugInfoRelocs;
std::vector<ValidReloc> ValidDebugAddrRelocs;
/// }
/// 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 up to date is all we have to do to have a
/// cheap lookup during the root DIE selection and during DIE cloning.
unsigned NextValidReloc = 0;
RangesTy AddressRanges;
AddressManager(DwarfLinkerForBinary &Linker, const object::ObjectFile &Obj,
const DebugMapObject &DMO)
: Linker(Linker) {
findValidRelocsInDebugSections(Obj, DMO);
// Iterate over the debug map entries and put all the ones that are
// functions (because they have a size) into the Ranges map. This map is
// very similar to the FunctionRanges that are stored in each unit, with 2
// notable differences:
// 1. Obviously this one is global, while the other ones are per-unit.
// 2. This one contains not only the functions described in the DIE
// tree, but also the ones that are only in the debug map.
// The latter information is required to reproduce dsymutil's logic while
// linking line tables. The cases where this information matters look like
// bugs that need to be investigated, but for now we need to reproduce
// dsymutil's behavior.
// FIXME: Once we understood exactly if that information is needed,
// maybe totally remove this (or try to use it to do a real
// -gline-tables-only on Darwin.
for (const auto &Entry : DMO.symbols()) {
const auto &Mapping = Entry.getValue();
if (Mapping.Size && Mapping.ObjectAddress)
AddressRanges[*Mapping.ObjectAddress] = ObjFileAddressRange(
*Mapping.ObjectAddress + Mapping.Size,
int64_t(Mapping.BinaryAddress) - *Mapping.ObjectAddress);
virtual ~AddressManager() override { clear(); }
virtual bool areRelocationsResolved() const override { return true; }
bool hasValidRelocs(bool ResetRelocsPtr = true) override {
if (ResetRelocsPtr)
NextValidReloc = 0;
return !ValidDebugInfoRelocs.empty() || !ValidDebugAddrRelocs.empty();
/// \defgroup FindValidRelocations Translate debug map into a list
/// of relevant relocations
/// @{
bool findValidRelocsInDebugSections(const object::ObjectFile &Obj,
const DebugMapObject &DMO);
bool findValidRelocs(const object::SectionRef &Section,
const object::ObjectFile &Obj,
const DebugMapObject &DMO,
std::vector<ValidReloc> &ValidRelocs);
void findValidRelocsMachO(const object::SectionRef &Section,
const object::MachOObjectFile &Obj,
const DebugMapObject &DMO,
std::vector<ValidReloc> &ValidRelocs);
/// @}
/// Checks that there is a relocation in the debug_addr section against a
/// 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 hasValidDebugInfoRelocationAt(uint64_t StartOffset, uint64_t EndOffset,
CompileUnit::DIEInfo &Info);
/// Checks that there is a relocation in the debug_addr section against a
/// debug map entry at the given offset.
bool hasValidDebugAddrRelocationAt(uint64_t Offset);
bool hasLiveMemoryLocation(const DWARFDie &DIE,
CompileUnit::DIEInfo &Info) override;
bool hasLiveAddressRange(const DWARFDie &DIE,
CompileUnit::DIEInfo &Info) override;
bool applyValidRelocs(MutableArrayRef<char> Data, uint64_t BaseOffset,
bool IsLittleEndian) override;
llvm::Expected<uint64_t> relocateIndexedAddr(uint64_t Offset) override;
RangesTy &getValidAddressRanges() override { return AddressRanges; }
void clear() override {
NextValidReloc = 0;
/// \defgroup Helpers Various helper methods.
/// @{
bool createStreamer(const Triple &TheTriple, raw_fd_ostream &OutFile);
/// Attempt to load a debug object from disk.
ErrorOr<const object::ObjectFile &> loadObject(const DebugMapObject &Obj,
const Triple &triple);
ErrorOr<DWARFFile &> loadObject(const DebugMapObject &Obj,
const DebugMap &DebugMap,
remarks::RemarkLinker &RL);
raw_fd_ostream &OutFile;
BinaryHolder &BinHolder;
LinkOptions Options;
std::unique_ptr<DwarfStreamer> Streamer;
std::vector<std::unique_ptr<DWARFFile>> ObjectsForLinking;
std::vector<std::unique_ptr<DWARFContext>> ContextForLinking;
std::vector<std::unique_ptr<AddressManager>> AddressMapForLinking;
std::vector<std::string> EmptyWarnings;
/// A list of all .swiftinterface files referenced by the debug
/// info, mapping Module name to path on disk. The entries need to
/// be uniqued and sorted and there are only few entries expected
/// per compile unit, which is why this is a std::map.
std::map<std::string, std::string> ParseableSwiftInterfaces;
bool ModuleCacheHintDisplayed = false;
bool ArchiveHintDisplayed = false;
} // end namespace dsymutil
} // end namespace llvm