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-rw-r--r--ELF/DWARF.cpp132
1 files changed, 76 insertions, 56 deletions
diff --git a/ELF/DWARF.cpp b/ELF/DWARF.cpp
index 17e1a4d600eb5..1e4b36f71b540 100644
--- a/ELF/DWARF.cpp
+++ b/ELF/DWARF.cpp
@@ -1,9 +1,8 @@
//===- DWARF.cpp ----------------------------------------------------------===//
//
-// The LLVM Linker
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
+// 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
//
//===----------------------------------------------------------------------===//
//
@@ -26,81 +25,102 @@ 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)
+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_addr", &AddrSection)
- .Case(".debug_gnu_pubnames", &GnuPubNamesSection)
- .Case(".debug_gnu_pubtypes", &GnuPubTypesSection)
- .Case(".debug_info", &InfoSection)
- .Case(".debug_ranges", &RangeSection)
- .Case(".debug_rnglists", &RngListsSection)
- .Case(".debug_line", &LineSection)
+ if (LLDDWARFSection *m =
+ StringSwitch<LLDDWARFSection *>(sec->name)
+ .Case(".debug_addr", &addrSection)
+ .Case(".debug_gnu_pubnames", &gnuPubNamesSection)
+ .Case(".debug_gnu_pubtypes", &gnuPubTypesSection)
+ .Case(".debug_info", &infoSection)
+ .Case(".debug_ranges", &rangeSection)
+ .Case(".debug_rnglists", &rngListsSection)
+ .Case(".debug_line", &lineSection)
.Default(nullptr)) {
- M->Data = toStringRef(Sec->data());
- M->Sec = Sec;
+ 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")
- LineStringSection = toStringRef(Sec->data());
+ 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")
+ lineStringSection = toStringRef(sec->data());
}
}
+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 = 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)
+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 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);
+ 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);
- // Broken debug info can point to a non-Defined symbol.
- auto *DR = dyn_cast<Defined>(&File->getRelocTargetSym(Rel));
- if (!DR) {
- RelType Type = Rel.getType(Config->IsMips64EL);
- if (Type != Target->NoneRel)
- error(toString(File) + ": relocation " + lld::toString(Type) + " at 0x" +
- llvm::utohexstr(Rel.r_offset) + " has unsupported target");
- return None;
- }
- uint64_t Val = DR->Value + getAddend<ELFT>(Rel);
+ // 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;
- // 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();
+ // 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};
+ 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>());
+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>;
generated by cgit v1.2.3 (git 2.25.1) at 2025-08-02 22:38:22 +0000