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📄 AArch64ErrataFix.cpp(25.49 KB)
📄 AArch64ErrataFix.h(1.35 KB)
📄 ARMErrataFix.cpp(21.67 KB)
📄 ARMErrataFix.h(1.38 KB)
📁 Arch
📄 CallGraphSort.cpp(8.81 KB)
📄 CallGraphSort.h(652 B)
📄 Config.h(10.49 KB)
📄 DWARF.cpp(5.75 KB)
📄 DWARF.h(2.97 KB)
📄 Driver.cpp(80.51 KB)
📄 Driver.h(2.1 KB)
📄 DriverUtils.cpp(8.74 KB)
📄 EhFrame.cpp(5.42 KB)
📄 EhFrame.h(680 B)
📄 ICF.cpp(19.74 KB)
📄 ICF.h(531 B)
📄 InputFiles.cpp(63.74 KB)
📄 InputFiles.h(12.88 KB)
📄 InputSection.cpp(54.78 KB)
📄 InputSection.h(14 KB)
📄 LTO.cpp(12.64 KB)
📄 LTO.h(1.65 KB)
📄 LinkerScript.cpp(44.6 KB)
📄 LinkerScript.h(10.59 KB)
📄 MapFile.cpp(9.1 KB)
📄 MapFile.h(581 B)
📄 MarkLive.cpp(14.18 KB)
📄 MarkLive.h(566 B)
📄 Options.td(27.47 KB)
📄 OutputSections.cpp(19.23 KB)
📄 OutputSections.h(4.73 KB)
📄 README.md(20 B)
📄 Relocations.cpp(81.61 KB)
📄 Relocations.h(5.89 KB)
📄 ScriptLexer.cpp(8.99 KB)
📄 ScriptLexer.h(1.31 KB)
📄 ScriptParser.cpp(48.05 KB)
📄 ScriptParser.h(961 B)
📄 SymbolTable.cpp(9.72 KB)
📄 SymbolTable.h(3.62 KB)
📄 Symbols.cpp(23.27 KB)
📄 Symbols.h(20.34 KB)
📄 SyntheticSections.cpp(134.95 KB)
📄 SyntheticSections.h(40.28 KB)
📄 Target.cpp(5.79 KB)
📄 Target.h(10.89 KB)
📄 Thunks.cpp(35.71 KB)
📄 Thunks.h(2.69 KB)
📄 Writer.cpp(108.98 KB)
📄 Writer.h(1.79 KB)

Editing: DWARF.cpp

//===- DWARF.cpp ----------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// The -gdb-index option instructs the linker to emit a .gdb_index section.
// The section contains information to make gdb startup faster.
// The format of the section is described at
// https://sourceware.org/gdb/onlinedocs/gdb/Index-Section-Format.html.
//
//===----------------------------------------------------------------------===//

#include "DWARF.h"
#include "Symbols.h"
#include "Target.h"
#include "lld/Common/Memory.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugPubTable.h"
#include "llvm/Object/ELFObjectFile.h"

using namespace llvm;
using namespace llvm::object;
using namespace lld;
using namespace lld::elf;

template <class ELFT> LLDDwarfObj<ELFT>::LLDDwarfObj(ObjFile<ELFT> *obj) {
  // Get the ELF sections to retrieve sh_flags. See the SHF_GROUP comment below.
  ArrayRef<typename ELFT::Shdr> objSections =
      CHECK(obj->getObj().sections(), obj);
  assert(objSections.size() == obj->getSections().size());
  for (auto it : llvm::enumerate(obj->getSections())) {
    InputSectionBase *sec = it.value();
    if (!sec)
      continue;

if (LLDDWARFSection *m =
            StringSwitch<LLDDWARFSection *>(sec->name)
                .Case(".debug_addr", &addrSection)
                .Case(".debug_gnu_pubnames", &gnuPubnamesSection)
                .Case(".debug_gnu_pubtypes", &gnuPubtypesSection)
                .Case(".debug_loclists", &loclistsSection)
                .Case(".debug_ranges", &rangesSection)
                .Case(".debug_rnglists", &rnglistsSection)
                .Case(".debug_str_offsets", &strOffsetsSection)
                .Case(".debug_line", &lineSection)
                .Default(nullptr)) {
      m->Data = toStringRef(sec->data());
      m->sec = sec;
      continue;
    }

if (sec->name == ".debug_abbrev")
      abbrevSection = toStringRef(sec->data());
    else if (sec->name == ".debug_str")
      strSection = toStringRef(sec->data());
    else if (sec->name == ".debug_line_str")
      lineStrSection = toStringRef(sec->data());
    else if (sec->name == ".debug_info" &&
             !(objSections[it.index()].sh_flags & ELF::SHF_GROUP)) {
      // In DWARF v5, -fdebug-types-section places type units in .debug_info
      // sections in COMDAT groups. They are not compile units and thus should
      // be ignored for .gdb_index/diagnostics purposes.
      //
      // We use a simple heuristic: the compile unit does not have the SHF_GROUP
      // flag. If we place compile units in COMDAT groups in the future, we may
      // need to perform a lightweight parsing. We drop the SHF_GROUP flag when
      // the InputSection was created, so we need to retrieve sh_flags from the
      // associated ELF section header.
      infoSection.Data = toStringRef(sec->data());
      infoSection.sec = sec;
    }
  }
}

namespace {
template <class RelTy> struct LLDRelocationResolver {
  // In the ELF ABIs, S sepresents the value of the symbol in the relocation
  // entry. For Rela, the addend is stored as part of the relocation entry.
  static uint64_t resolve(object::RelocationRef ref, uint64_t s,
                          uint64_t /* A */) {
    return s + ref.getRawDataRefImpl().p;
  }
};

template <class ELFT> struct LLDRelocationResolver<Elf_Rel_Impl<ELFT, false>> {
  // For Rel, the addend A is supplied by the caller.
  static uint64_t resolve(object::RelocationRef /*Ref*/, uint64_t s,
                          uint64_t a) {
    return s + a;
  }
};
} // namespace

// Find if there is a relocation at Pos in Sec.  The code is a bit
// more complicated than usual because we need to pass a section index
// to llvm since it has no idea about InputSection.
template <class ELFT>
template <class RelTy>
Optional<RelocAddrEntry>
LLDDwarfObj<ELFT>::findAux(const InputSectionBase &sec, uint64_t pos,
                           ArrayRef<RelTy> rels) const {
  auto it =
      partition_point(rels, [=](const RelTy &a) { return a.r_offset < pos; });
  if (it == rels.end() || it->r_offset != pos)
    return None;
  const RelTy &rel = *it;

const ObjFile<ELFT> *file = sec.getFile<ELFT>();
  uint32_t symIndex = rel.getSymbol(config->isMips64EL);
  const typename ELFT::Sym &sym = file->template getELFSyms<ELFT>()[symIndex];
  uint32_t secIndex = file->getSectionIndex(sym);

// An undefined symbol may be a symbol defined in a discarded section. We
  // shall still resolve it. This is important for --gdb-index: the end address
  // offset of an entry in .debug_ranges is relocated. If it is not resolved,
  // its zero value will terminate the decoding of .debug_ranges prematurely.
  Symbol &s = file->getRelocTargetSym(rel);
  uint64_t val = 0;
  if (auto *dr = dyn_cast<Defined>(&s))
    val = dr->value;

DataRefImpl d;
  d.p = getAddend<ELFT>(rel);
  return RelocAddrEntry{secIndex, RelocationRef(d, nullptr),
                        val,      Optional<object::RelocationRef>(),
                        0,        LLDRelocationResolver<RelTy>::resolve};
}

template <class ELFT>
Optional<RelocAddrEntry> LLDDwarfObj<ELFT>::find(const llvm::DWARFSection &s,
                                                 uint64_t pos) const {
  auto &sec = static_cast<const LLDDWARFSection &>(s);
  if (sec.sec->areRelocsRela)
    return findAux(*sec.sec, pos, sec.sec->template relas<ELFT>());
  return findAux(*sec.sec, pos, sec.sec->template rels<ELFT>());
}

template class elf::LLDDwarfObj<ELF32LE>;
template class elf::LLDDwarfObj<ELF32BE>;
template class elf::LLDDwarfObj<ELF64LE>;
template class elf::LLDDwarfObj<ELF64BE>;

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Editing: DWARF.cpp

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