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[yaml2obj/obj2yaml] - Add support for SHT_RELR sections. 

Note: this is a reland with a trivial 2 lines fix in ELFState<ELFT>::writeSectionContent.
      It adds a check similar to ones we already have for other sections to fix the case revealed
      by bots, like http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/60744.

The encoded sequence of Elf*_Relr entries in a SHT_RELR section looks
like [ AAAAAAAA BBBBBBB1 BBBBBBB1 ... AAAAAAAA BBBBBB1 ... ]
i.e. start with an address, followed by any number of bitmaps. The address
entry encodes 1 relocation. The subsequent bitmap entries encode up to 63(31)
relocations each, at subsequent offsets following the last address entry.

More information is here:
https://github.com/llvm-mirror/llvm/blob/master/lib/Object/ELF.cpp#L272

This patch adds a support for these sections.

Differential revision: https://reviews.llvm.org/D71872
This commit is contained in:
Georgii Rymar 2020-01-15 14:29:29 +03:00
parent 13f22f5d59
commit 7570d387c2
4 changed files with 95 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
llvm/include/llvm/ObjectYAML/ELFYAML.h
View File

@ -138,6 +138,7 @@ struct Chunk {
Group,
RawContent,
Relocation,
Relr,
NoBits,
Note,
Hash,
@ -440,6 +441,17 @@ struct RelocationSection : Section {
}
};
struct RelrSection : Section {
Optional<std::vector<llvm::yaml::Hex64>> Entries;
Optional<yaml::BinaryRef> Content;
RelrSection() : Section(ChunkKind::Relr) {}
static bool classof(const Chunk *S) {
return S->Kind == ChunkKind::Relr;
}
};
struct SymtabShndxSection : Section {
std::vector<uint32_t> Entries;

40
llvm/lib/ObjectYAML/ELFEmitter.cpp
View File

@ -110,6 +110,7 @@ template <class ELFT> class ELFState {
typedef typename ELFT::Rela Elf_Rela;
typedef typename ELFT::Relr Elf_Relr;
typedef typename ELFT::Dyn Elf_Dyn;
typedef typename ELFT::uint uintX_t;
enum class SymtabType { Static, Dynamic };
@ -165,6 +166,9 @@ template <class ELFT> class ELFState {
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::RelocationSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::RelrSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader, const ELFYAML::Group &Group,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
@ -454,6 +458,8 @@ void ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::RelocationSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::RelrSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::Group>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::MipsABIFlags>(Sec)) {
@ -770,10 +776,6 @@ void ELFState<ELFT>::writeSectionContent(
if (Section.EntSize)
SHeader.sh_entsize = *Section.EntSize;
else if (Section.Type == llvm::ELF::SHT_RELR)
SHeader.sh_entsize = sizeof(Elf_Relr);
else
SHeader.sh_entsize = 0;
if (Section.Info)
SHeader.sh_info = *Section.Info;
@ -827,6 +829,33 @@ void ELFState<ELFT>::writeSectionContent(
}
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::RelrSection &Section,
ContiguousBlobAccumulator &CBA) {
raw_ostream &OS =
CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
SHeader.sh_entsize =
Section.EntSize ? uint64_t(*Section.EntSize) : sizeof(Elf_Relr);
if (Section.Content) {
SHeader.sh_size = writeContent(OS, Section.Content, None);
return;
}
if (!Section.Entries)
return;
for (llvm::yaml::Hex64 E : *Section.Entries) {
if (!ELFT::Is64Bits && E > UINT32_MAX)
reportError(Section.Name + ": the value is too large for 32-bits: 0x" +
Twine::utohexstr(E));
support::endian::write<uintX_t>(OS, E, ELFT::TargetEndianness);
}
SHeader.sh_size = sizeof(uintX_t) * Section.Entries->size();
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(
Elf_Shdr &SHeader, const ELFYAML::SymtabShndxSection &Shndx,
@ -889,7 +918,6 @@ template <class ELFT>
void ELFState<ELFT>::writeSectionContent(
Elf_Shdr &SHeader, const ELFYAML::StackSizesSection &Section,
ContiguousBlobAccumulator &CBA) {
using uintX_t = typename ELFT::uint;
raw_ostream &OS =
CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
@ -1115,8 +1143,6 @@ template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::DynamicSection &Section,
ContiguousBlobAccumulator &CBA) {
typedef typename ELFT::uint uintX_t;
assert(Section.Type == llvm::ELF::SHT_DYNAMIC &&
"Section type is not SHT_DYNAMIC");

17
llvm/lib/ObjectYAML/ELFYAML.cpp
View File

@ -1101,6 +1101,12 @@ static void sectionMapping(IO &IO, ELFYAML::RelocationSection &Section) {
IO.mapOptional("Relocations", Section.Relocations);
}
static void sectionMapping(IO &IO, ELFYAML::RelrSection &Section) {
commonSectionMapping(IO, Section);
IO.mapOptional("Entries", Section.Entries);
IO.mapOptional("Content", Section.Content);
}
static void groupSectionMapping(IO &IO, ELFYAML::Group &Group) {
commonSectionMapping(IO, Group);
IO.mapOptional("Info", Group.Signature);
@ -1200,6 +1206,11 @@ void MappingTraits<std::unique_ptr<ELFYAML::Chunk>>::mapping(
Section.reset(new ELFYAML::RelocationSection());
sectionMapping(IO, *cast<ELFYAML::RelocationSection>(Section.get()));
break;
case ELF::SHT_RELR:
if (!IO.outputting())
Section.reset(new ELFYAML::RelrSection());
sectionMapping(IO, *cast<ELFYAML::RelrSection>(Section.get()));
break;
case ELF::SHT_GROUP:
if (!IO.outputting())
Section.reset(new ELFYAML::Group());
@ -1441,6 +1452,12 @@ StringRef MappingTraits<std::unique_ptr<ELFYAML::Chunk>>::validate(
return {};
}
if (const auto *RS = dyn_cast<ELFYAML::RelrSection>(C.get())) {
if (RS->Entries && RS->Content)
return "\"Entries\" and \"Content\" can't be used together";
return {};
}
return {};
}

33
llvm/tools/obj2yaml/elf2yaml.cpp
View File

@ -27,6 +27,7 @@ class ELFDumper {
typedef typename ELFT::Word Elf_Word;
typedef typename ELFT::Rel Elf_Rel;
typedef typename ELFT::Rela Elf_Rela;
using Elf_Relr = typename ELFT::Relr;
using Elf_Nhdr = typename ELFT::Nhdr;
using Elf_Note = typename ELFT::Note;
@ -66,6 +67,7 @@ class ELFDumper {
dumpDependentLibrariesSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::DynamicSection *> dumpDynamicSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::RelocationSection *> dumpRelocSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::RelrSection *> dumpRelrSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::RawContentSection *>
dumpContentSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::SymtabShndxSection *>
@ -251,6 +253,13 @@ template <class ELFT> Expected<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
Y->Chunks.emplace_back(*SecOrErr);
break;
}
case ELF::SHT_RELR: {
Expected<ELFYAML::RelrSection *> SecOrErr = dumpRelrSection(&Sec);
if (!SecOrErr)
return SecOrErr.takeError();
Y->Chunks.emplace_back(*SecOrErr);
break;
}
case ELF::SHT_GROUP: {
Expected<ELFYAML::Group *> GroupOrErr = dumpGroup(&Sec);
if (!GroupOrErr)
@ -723,6 +732,30 @@ ELFDumper<ELFT>::dumpRelocSection(const Elf_Shdr *Shdr) {
return S.release();
}
template <class ELFT>
Expected<ELFYAML::RelrSection *>
ELFDumper<ELFT>::dumpRelrSection(const Elf_Shdr *Shdr) {
auto S = std::make_unique<ELFYAML::RelrSection>();
if (auto E = dumpCommonSection(Shdr, *S))
return std::move(E);
if (Expected<ArrayRef<Elf_Relr>> Relrs = Obj.relrs(Shdr)) {
S->Entries.emplace();
for (Elf_Relr Rel : *Relrs)
S->Entries->emplace_back(Rel);
return S.release();
} else {
// Ignore. We are going to dump the data as raw content below.
consumeError(Relrs.takeError());
}
Expected<ArrayRef<uint8_t>> ContentOrErr = Obj.getSectionContents(Shdr);
if (!ContentOrErr)
return ContentOrErr.takeError();
S->Content = *ContentOrErr;
return S.release();
}
template <class ELFT>
Expected<ELFYAML::RawContentSection *>
ELFDumper<ELFT>::dumpContentSection(const Elf_Shdr *Shdr) {