[llvm] 78cb1ad - [Object] Move llvm-nm's symbol version utility to ELFObjectFile::readDynsymVersions
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 17 09:06:44 PDT 2021
Author: Fangrui Song
Date: 2021-08-17T09:06:39-07:00
New Revision: 78cb1adc5c17850e1a1b33f78f5657ca38493c8d
URL: https://github.com/llvm/llvm-project/commit/78cb1adc5c17850e1a1b33f78f5657ca38493c8d
DIFF: https://github.com/llvm/llvm-project/commit/78cb1adc5c17850e1a1b33f78f5657ca38493c8d.diff
LOG: [Object] Move llvm-nm's symbol version utility to ELFObjectFile::readDynsymVersions
The utility can be reused by llvm-objdump -T.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D108096
Added:
Modified:
llvm/include/llvm/Object/ELFObjectFile.h
llvm/lib/Object/ELFObjectFile.cpp
llvm/tools/llvm-nm/llvm-nm.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/Object/ELFObjectFile.h b/llvm/include/llvm/Object/ELFObjectFile.h
index c87a09f86fae1..386dd24f52efc 100644
--- a/llvm/include/llvm/Object/ELFObjectFile.h
+++ b/llvm/include/llvm/Object/ELFObjectFile.h
@@ -96,6 +96,10 @@ class ELFObjectFileBase : public ObjectFile {
std::vector<std::pair<Optional<DataRefImpl>, uint64_t>>
getPltAddresses() const;
+
+ /// Returns a vector containing a symbol version for each dynamic symbol.
+ /// Returns an empty vector if version sections do not exist.
+ Expected<std::vector<VersionEntry>> readDynsymVersions() const;
};
class ELFSectionRef : public SectionRef {
diff --git a/llvm/lib/Object/ELFObjectFile.cpp b/llvm/lib/Object/ELFObjectFile.cpp
index 9efb28c6da2b3..2d6d25d2688d4 100644
--- a/llvm/lib/Object/ELFObjectFile.cpp
+++ b/llvm/lib/Object/ELFObjectFile.cpp
@@ -654,3 +654,72 @@ ELFObjectFileBase::getPltAddresses() const {
}
return Result;
}
+
+template <class ELFT>
+static Expected<std::vector<VersionEntry>>
+readDynsymVersionsImpl(const ELFFile<ELFT> &EF,
+ ELFObjectFileBase::elf_symbol_iterator_range Symbols) {
+ using Elf_Shdr = typename ELFT::Shdr;
+ const Elf_Shdr *VerSec = nullptr;
+ const Elf_Shdr *VerNeedSec = nullptr;
+ const Elf_Shdr *VerDefSec = nullptr;
+ // The user should ensure sections() can't fail here.
+ for (const Elf_Shdr &Sec : cantFail(EF.sections())) {
+ if (Sec.sh_type == ELF::SHT_GNU_versym)
+ VerSec = &Sec;
+ else if (Sec.sh_type == ELF::SHT_GNU_verdef)
+ VerDefSec = &Sec;
+ else if (Sec.sh_type == ELF::SHT_GNU_verneed)
+ VerNeedSec = &Sec;
+ }
+ if (!VerSec)
+ return std::vector<VersionEntry>();
+
+ Expected<SmallVector<Optional<VersionEntry>, 0>> MapOrErr =
+ EF.loadVersionMap(VerNeedSec, VerDefSec);
+ if (!MapOrErr)
+ return MapOrErr.takeError();
+
+ std::vector<VersionEntry> Ret;
+ size_t I = 0;
+ for (auto It = Symbols.begin(), E = Symbols.end(); It != E; ++It) {
+ ++I;
+ Expected<const typename ELFT::Versym *> VerEntryOrErr =
+ EF.template getEntry<typename ELFT::Versym>(*VerSec, I);
+ if (!VerEntryOrErr)
+ return createError("unable to read an entry with index " + Twine(I) +
+ " from " + describe(EF, *VerSec) + ": " +
+ toString(VerEntryOrErr.takeError()));
+
+ Expected<uint32_t> FlagsOrErr = It->getFlags();
+ if (!FlagsOrErr)
+ return createError("unable to read flags for symbol with index " +
+ Twine(I) + ": " + toString(FlagsOrErr.takeError()));
+
+ bool IsDefault;
+ Expected<StringRef> VerOrErr = EF.getSymbolVersionByIndex(
+ (*VerEntryOrErr)->vs_index, IsDefault, *MapOrErr,
+ (*FlagsOrErr) & SymbolRef::SF_Undefined);
+ if (!VerOrErr)
+ return createError("unable to get a version for entry " + Twine(I) +
+ " of " + describe(EF, *VerSec) + ": " +
+ toString(VerOrErr.takeError()));
+
+ Ret.push_back({(*VerOrErr).str(), IsDefault});
+ }
+
+ return Ret;
+}
+
+Expected<std::vector<VersionEntry>>
+ELFObjectFileBase::readDynsymVersions() const {
+ elf_symbol_iterator_range Symbols = getDynamicSymbolIterators();
+ if (const auto *Obj = dyn_cast<ELF32LEObjectFile>(this))
+ return readDynsymVersionsImpl(Obj->getELFFile(), Symbols);
+ if (const auto *Obj = dyn_cast<ELF32BEObjectFile>(this))
+ return readDynsymVersionsImpl(Obj->getELFFile(), Symbols);
+ if (const auto *Obj = dyn_cast<ELF64LEObjectFile>(this))
+ return readDynsymVersionsImpl(Obj->getELFFile(), Symbols);
+ return readDynsymVersionsImpl(cast<ELF64BEObjectFile>(this)->getELFFile(),
+ Symbols);
+}
diff --git a/llvm/tools/llvm-nm/llvm-nm.cpp b/llvm/tools/llvm-nm/llvm-nm.cpp
index ffb427a3f2bdf..f713fb8eb35f9 100644
--- a/llvm/tools/llvm-nm/llvm-nm.cpp
+++ b/llvm/tools/llvm-nm/llvm-nm.cpp
@@ -1575,90 +1575,11 @@ static void dumpSymbolsFromDLInfoMachO(MachOObjectFile &MachO) {
}
}
-namespace {
-struct SymbolVersion {
- std::string Name;
- bool IsDefault;
-};
-} // namespace
-
-template <class ELFT>
-static Expected<std::vector<SymbolVersion>>
-readSymbolVersionsELF(const ELFFile<ELFT> &Obj, StringRef FileName,
- ELFObjectFileBase::elf_symbol_iterator_range Symbols) {
- using Elf_Shdr = typename ELFT::Shdr;
-
- // We called sections() earlier, so can't fail here.
- typename ELFT::ShdrRange SectionsOrErr = cantFail(Obj.sections());
- const Elf_Shdr *SymVerSec = nullptr;
- const Elf_Shdr *SymVerNeedSec = nullptr;
- const Elf_Shdr *SymVerDefSec = nullptr;
- for (const Elf_Shdr &Sec : SectionsOrErr) {
- if (Sec.sh_type == ELF::SHT_GNU_versym)
- SymVerSec = &Sec;
- else if (Sec.sh_type == ELF::SHT_GNU_verdef)
- SymVerDefSec = &Sec;
- else if (Sec.sh_type == ELF::SHT_GNU_verneed)
- SymVerNeedSec = &Sec;
- }
-
- if (!SymVerSec)
- return std::vector<SymbolVersion>{};
-
- Expected<SmallVector<Optional<VersionEntry>, 0>> MapOrErr =
- Obj.loadVersionMap(SymVerNeedSec, SymVerDefSec);
- if (!MapOrErr)
- return MapOrErr.takeError();
-
- std::vector<SymbolVersion> Ret;
- size_t I = 0;
- for (auto It = Symbols.begin(), E = Symbols.end(); It != E; ++It) {
- ++I;
- Expected<const typename ELFT::Versym *> VerEntryOrErr =
- Obj.template getEntry<typename ELFT::Versym>(*SymVerSec, I);
- if (!VerEntryOrErr)
- return createError("unable to read an entry with index " + Twine(I) +
- " from " + describe(Obj, *SymVerSec) + ": " +
- toString(VerEntryOrErr.takeError()));
-
- Expected<uint32_t> FlagsOrErr = It->getFlags();
- if (!FlagsOrErr)
- return createError("unable to read flags for symbol with index " +
- Twine(I) + ": " + toString(FlagsOrErr.takeError()));
-
- bool IsDefault;
- Expected<StringRef> VerOrErr = Obj.getSymbolVersionByIndex(
- (*VerEntryOrErr)->vs_index, IsDefault, *MapOrErr,
- (*FlagsOrErr) & SymbolRef::SF_Undefined);
- if (!VerOrErr)
- return createError("unable to get a version for entry " + Twine(I) +
- " of " + describe(Obj, *SymVerSec) + ": " +
- toString(VerOrErr.takeError()));
-
- Ret.push_back({(*VerOrErr).str(), IsDefault});
- }
-
- return Ret;
-}
-
-static Expected<std::vector<SymbolVersion>>
-readSymbolVersionsELF(const ELFObjectFileBase &Obj,
- ELFObjectFileBase::elf_symbol_iterator_range Symbols) {
- if (const auto *ELF = dyn_cast<ELF32LEObjectFile>(&Obj))
- return readSymbolVersionsELF(ELF->getELFFile(), Obj.getFileName(), Symbols);
- else if (const auto *ELF = dyn_cast<ELF32BEObjectFile>(&Obj))
- return readSymbolVersionsELF(ELF->getELFFile(), Obj.getFileName(), Symbols);
- else if (const auto *ELF = dyn_cast<ELF64LEObjectFile>(&Obj))
- return readSymbolVersionsELF(ELF->getELFFile(), Obj.getFileName(), Symbols);
- return readSymbolVersionsELF(cast<ELF64BEObjectFile>(&Obj)->getELFFile(),
- Obj.getFileName(), Symbols);
-}
-
static void dumpSymbolNamesFromObject(SymbolicFile &Obj, bool printName,
StringRef ArchiveName = {},
StringRef ArchitectureName = {}) {
auto Symbols = Obj.symbols();
- std::vector<SymbolVersion> SymbolVersions;
+ std::vector<VersionEntry> SymbolVersions;
if (DynamicSyms) {
const auto *E = dyn_cast<ELFObjectFileBase>(&Obj);
if (!E) {
@@ -1667,8 +1588,8 @@ static void dumpSymbolNamesFromObject(SymbolicFile &Obj, bool printName,
}
Symbols = E->getDynamicSymbolIterators();
- if (Expected<std::vector<SymbolVersion>> VersionsOrErr =
- readSymbolVersionsELF(*E, Symbols))
+ if (Expected<std::vector<VersionEntry>> VersionsOrErr =
+ E->readDynsymVersions())
SymbolVersions = std::move(*VersionsOrErr);
else
WithColor::warning(errs(), ToolName)
@@ -1738,7 +1659,7 @@ static void dumpSymbolNamesFromObject(SymbolicFile &Obj, bool printName,
}
if (!SymbolVersions.empty() && !SymbolVersions[I].Name.empty())
S.Name +=
- (SymbolVersions[I].IsDefault ? "@@" : "@") + SymbolVersions[I].Name;
+ (SymbolVersions[I].IsVerDef ? "@@" : "@") + SymbolVersions[I].Name;
S.Sym = Sym;
SymbolList.push_back(S);
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