102 lines
3.7 KiB
C++
102 lines
3.7 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 "Symbols.h"
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#include "lld/Common/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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else if (Sec->Name == ".debug_str")
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StrSection = 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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// Broken debug info can point to a non-Defined symbol.
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auto *DR = dyn_cast<Defined>(&File->getRelocTargetSym(Rel));
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if (!DR) {
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error("unsupported relocation target while parsing debug info");
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return None;
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}
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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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