llvm-project/lld/ELF/GdbIndex.cpp
George Rimar 5f928ff133 [ELF] - Teach LLD to use information from .debug_str for error reporting.
Recently we teached LLD to report line numbers for duplicate variables
definitions, though currently LLD is unable to do that for case when
strings are not built in .debug_info, but stored in .debug_str instead.
That is because out LLDDwarfObj does not handle .debug_str yet. 
Patch fixes that.

Differential revision: https://reviews.llvm.org/D39542

llvm-svn: 318519
2017-11-17 11:57:47 +00:00

96 lines
3.6 KiB
C++

//===- GdbIndex.cpp -------------------------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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 "GdbIndex.h"
#include "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) {
for (InputSectionBase *Sec : Obj->getSections()) {
if (!Sec)
continue;
if (LLDDWARFSection *M = StringSwitch<LLDDWARFSection *>(Sec->Name)
.Case(".debug_info", &InfoSection)
.Case(".debug_ranges", &RangeSection)
.Case(".debug_line", &LineSection)
.Default(nullptr)) {
Sec->maybeUncompress();
M->Data = toStringRef(Sec->Data);
M->Sec = Sec;
continue;
}
if (Sec->Name == ".debug_abbrev")
AbbrevSection = toStringRef(Sec->Data);
else if (Sec->Name == ".debug_gnu_pubnames")
GnuPubNamesSection = toStringRef(Sec->Data);
else if (Sec->Name == ".debug_gnu_pubtypes")
GnuPubTypesSection = toStringRef(Sec->Data);
else if (Sec->Name == ".debug_str")
StrSection = toStringRef(Sec->Data);
}
}
// 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 = std::lower_bound(
Rels.begin(), Rels.end(), Pos,
[](const RelTy &A, uint64_t B) { return A.r_offset < B; });
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->getELFSyms()[SymIndex];
uint32_t SecIndex = File->getSectionIndex(Sym);
Symbol &B = File->getRelocTargetSym(Rel);
auto &DR = cast<Defined>(B);
uint64_t Val = DR.Value + getAddend<ELFT>(Rel);
// FIXME: We should be consistent about always adding the file
// offset or not.
if (DR.Section->Flags & ELF::SHF_ALLOC)
Val += cast<InputSection>(DR.Section)->getOffsetInFile();
return RelocAddrEntry{SecIndex, Val};
}
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>;