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When reporting a symbol conflict, LLD parses the debug info to report source location information. Sections have not been decompressed at this point, so if an object file contains zlib compressed debug info, LLD ends up passing this compressed debug info to the DWARF parser, which causes debug info parsing failures and can trigger assertions in the parser (as the test case demonstrates). Decompress debug sections when constructing the LLDDwarfObj to avoid this issue. This doesn't handle GNU-style compressed debug info sections (.zdebug_*), which at present are simply ignored by LLDDwarfObj; those can be done in a follow-up. Differential Revision: https://reviews.llvm.org/D38491 llvm-svn: 314866
94 lines
3.5 KiB
C++
94 lines
3.5 KiB
C++
//===- GdbIndex.cpp -------------------------------------------------------===//
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//
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// The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// The -gdb-index option instructs the linker to emit a .gdb_index section.
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// The section contains information to make gdb startup faster.
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// The format of the section is described at
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// https://sourceware.org/gdb/onlinedocs/gdb/Index-Section-Format.html.
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//
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//===----------------------------------------------------------------------===//
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#include "GdbIndex.h"
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#include "Memory.h"
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#include "llvm/DebugInfo/DWARF/DWARFDebugPubTable.h"
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#include "llvm/Object/ELFObjectFile.h"
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using namespace llvm;
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using namespace llvm::object;
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using namespace lld;
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using namespace lld::elf;
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template <class ELFT> LLDDwarfObj<ELFT>::LLDDwarfObj(ObjFile<ELFT> *Obj) {
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for (InputSectionBase *Sec : Obj->getSections()) {
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if (!Sec)
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continue;
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if (LLDDWARFSection *M = StringSwitch<LLDDWARFSection *>(Sec->Name)
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.Case(".debug_info", &InfoSection)
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.Case(".debug_ranges", &RangeSection)
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.Case(".debug_line", &LineSection)
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.Default(nullptr)) {
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Sec->maybeUncompress();
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M->Data = toStringRef(Sec->Data);
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M->Sec = Sec;
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continue;
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}
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if (Sec->Name == ".debug_abbrev")
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AbbrevSection = toStringRef(Sec->Data);
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else if (Sec->Name == ".debug_gnu_pubnames")
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GnuPubNamesSection = toStringRef(Sec->Data);
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else if (Sec->Name == ".debug_gnu_pubtypes")
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GnuPubTypesSection = toStringRef(Sec->Data);
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}
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}
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// Find if there is a relocation at Pos in Sec. The code is a bit
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// more complicated than usual because we need to pass a section index
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// to llvm since it has no idea about InputSection.
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template <class ELFT>
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template <class RelTy>
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Optional<RelocAddrEntry>
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LLDDwarfObj<ELFT>::findAux(const InputSectionBase &Sec, uint64_t Pos,
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ArrayRef<RelTy> Rels) const {
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auto It = std::lower_bound(
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Rels.begin(), Rels.end(), Pos,
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[](const RelTy &A, uint64_t B) { return A.r_offset < B; });
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if (It == Rels.end() || It->r_offset != Pos)
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return None;
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const RelTy &Rel = *It;
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const ObjFile<ELFT> *File = Sec.getFile<ELFT>();
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uint32_t SymIndex = Rel.getSymbol(Config->IsMips64EL);
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const typename ELFT::Sym &Sym = File->getELFSyms()[SymIndex];
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uint32_t SecIndex = File->getSectionIndex(Sym);
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SymbolBody &B = File->getRelocTargetSym(Rel);
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auto &DR = cast<DefinedRegular>(B);
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uint64_t Val = DR.Value + getAddend<ELFT>(Rel);
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// FIXME: We should be consistent about always adding the file
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// offset or not.
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if (DR.Section->Flags & ELF::SHF_ALLOC)
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Val += cast<InputSection>(DR.Section)->getOffsetInFile();
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return RelocAddrEntry{SecIndex, Val};
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}
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template <class ELFT>
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Optional<RelocAddrEntry> LLDDwarfObj<ELFT>::find(const llvm::DWARFSection &S,
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uint64_t Pos) const {
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auto &Sec = static_cast<const LLDDWARFSection &>(S);
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if (Sec.Sec->AreRelocsRela)
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return findAux(*Sec.Sec, Pos, Sec.Sec->template relas<ELFT>());
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return findAux(*Sec.Sec, Pos, Sec.Sec->template rels<ELFT>());
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}
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template class elf::LLDDwarfObj<ELF32LE>;
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template class elf::LLDDwarfObj<ELF32BE>;
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template class elf::LLDDwarfObj<ELF64LE>;
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template class elf::LLDDwarfObj<ELF64BE>;
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