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Move to llvm-readobj code that is only used there. 

lld might end up using a small part of this, but it will be in a much
refactored form. For now this unblocks avoiding the full section scan in the
ELFFile constructor.

This also has a (very small) error handling improvement.

llvm-svn: 244282
This commit is contained in:
Rafael Espindola 2015-08-06 21:54:37 +00:00
parent 03c9cd0852
commit 8b3b09fdcf
4 changed files with 216 additions and 215 deletions
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192
llvm/include/llvm/Object/ELF.h
View File

@ -105,36 +105,6 @@ private:
const Elf_Shdr *SymbolTableSectionHeaderIndex = nullptr;
DenseMap<const Elf_Sym *, ELF::Elf64_Word> ExtendedSymbolTable;
const Elf_Shdr *dot_gnu_version_sec = nullptr; // .gnu.version
const Elf_Shdr *dot_gnu_version_r_sec = nullptr; // .gnu.version_r
const Elf_Shdr *dot_gnu_version_d_sec = nullptr; // .gnu.version_d
// Records for each version index the corresponding Verdef or Vernaux entry.
// This is filled the first time LoadVersionMap() is called.
class VersionMapEntry : public PointerIntPair<const void*, 1> {
public:
// If the integer is 0, this is an Elf_Verdef*.
// If the integer is 1, this is an Elf_Vernaux*.
VersionMapEntry() : PointerIntPair<const void*, 1>(nullptr, 0) { }
VersionMapEntry(const Elf_Verdef *verdef)
: PointerIntPair<const void*, 1>(verdef, 0) { }
VersionMapEntry(const Elf_Vernaux *vernaux)
: PointerIntPair<const void*, 1>(vernaux, 1) { }
bool isNull() const { return getPointer() == nullptr; }
bool isVerdef() const { return !isNull() && getInt() == 0; }
bool isVernaux() const { return !isNull() && getInt() == 1; }
const Elf_Verdef *getVerdef() const {
return isVerdef() ? (const Elf_Verdef*)getPointer() : nullptr;
}
const Elf_Vernaux *getVernaux() const {
return isVernaux() ? (const Elf_Vernaux*)getPointer() : nullptr;
}
};
mutable SmallVector<VersionMapEntry, 16> VersionMap;
void LoadVersionDefs(const Elf_Shdr *sec) const;
void LoadVersionNeeds(const Elf_Shdr *ec) const;
void LoadVersionMap() const;
public:
template<typename T>
const T *getEntry(uint32_t Section, uint32_t Entry) const;
@ -147,8 +117,6 @@ public:
ErrorOr<StringRef> getStringTable(const Elf_Shdr *Section) const;
ErrorOr<StringRef> getStringTableForSymtab(const Elf_Shdr &Section) const;
ErrorOr<StringRef> getSymbolVersion(StringRef StrTab, const Elf_Sym *Symb,
bool &IsDefault) const;
void VerifyStrTab(const Elf_Shdr *sh) const;
StringRef getRelocationTypeName(uint32_t Type) const;
@ -282,87 +250,6 @@ typedef ELFFile<ELFType<support::little, true>> ELF64LEFile;
typedef ELFFile<ELFType<support::big, false>> ELF32BEFile;
typedef ELFFile<ELFType<support::big, true>> ELF64BEFile;
// Iterate through the version definitions, and place each Elf_Verdef
// in the VersionMap according to its index.
template <class ELFT>
void ELFFile<ELFT>::LoadVersionDefs(const Elf_Shdr *sec) const {
unsigned vd_size = sec->sh_size; // Size of section in bytes
unsigned vd_count = sec->sh_info; // Number of Verdef entries
const char *sec_start = (const char*)base() + sec->sh_offset;
const char *sec_end = sec_start + vd_size;
// The first Verdef entry is at the start of the section.
const char *p = sec_start;
for (unsigned i = 0; i < vd_count; i++) {
if (p + sizeof(Elf_Verdef) > sec_end)
report_fatal_error("Section ended unexpectedly while scanning "
"version definitions.");
const Elf_Verdef *vd = reinterpret_cast<const Elf_Verdef *>(p);
if (vd->vd_version != ELF::VER_DEF_CURRENT)
report_fatal_error("Unexpected verdef version");
size_t index = vd->vd_ndx & ELF::VERSYM_VERSION;
if (index >= VersionMap.size())
VersionMap.resize(index + 1);
VersionMap[index] = VersionMapEntry(vd);
p += vd->vd_next;
}
}
// Iterate through the versions needed section, and place each Elf_Vernaux
// in the VersionMap according to its index.
template <class ELFT>
void ELFFile<ELFT>::LoadVersionNeeds(const Elf_Shdr *sec) const {
unsigned vn_size = sec->sh_size; // Size of section in bytes
unsigned vn_count = sec->sh_info; // Number of Verneed entries
const char *sec_start = (const char *)base() + sec->sh_offset;
const char *sec_end = sec_start + vn_size;
// The first Verneed entry is at the start of the section.
const char *p = sec_start;
for (unsigned i = 0; i < vn_count; i++) {
if (p + sizeof(Elf_Verneed) > sec_end)
report_fatal_error("Section ended unexpectedly while scanning "
"version needed records.");
const Elf_Verneed *vn = reinterpret_cast<const Elf_Verneed *>(p);
if (vn->vn_version != ELF::VER_NEED_CURRENT)
report_fatal_error("Unexpected verneed version");
// Iterate through the Vernaux entries
const char *paux = p + vn->vn_aux;
for (unsigned j = 0; j < vn->vn_cnt; j++) {
if (paux + sizeof(Elf_Vernaux) > sec_end)
report_fatal_error("Section ended unexpected while scanning auxiliary "
"version needed records.");
const Elf_Vernaux *vna = reinterpret_cast<const Elf_Vernaux *>(paux);
size_t index = vna->vna_other & ELF::VERSYM_VERSION;
if (index >= VersionMap.size())
VersionMap.resize(index + 1);
VersionMap[index] = VersionMapEntry(vna);
paux += vna->vna_next;
}
p += vn->vn_next;
}
}
template <class ELFT>
void ELFFile<ELFT>::LoadVersionMap() const {
// If there is no dynamic symtab or version table, there is nothing to do.
if (!DotDynSymSec || !dot_gnu_version_sec)
return;
// Has the VersionMap already been loaded?
if (VersionMap.size() > 0)
return;
// The first two version indexes are reserved.
// Index 0 is LOCAL, index 1 is GLOBAL.
VersionMap.push_back(VersionMapEntry());
VersionMap.push_back(VersionMapEntry());
if (dot_gnu_version_d_sec)
LoadVersionDefs(dot_gnu_version_d_sec);
if (dot_gnu_version_r_sec)
LoadVersionNeeds(dot_gnu_version_r_sec);
}
template <class ELFT>
ELF::Elf64_Word
ELFFile<ELFT>::getExtendedSymbolTableIndex(const Elf_Sym *symb) const {
@ -530,30 +417,6 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
DotDynSymSec = &Sec;
break;
}
case ELF::SHT_GNU_versym:
if (dot_gnu_version_sec != nullptr) {
// More than one .gnu.version section!
EC = object_error::parse_failed;
return;
}
dot_gnu_version_sec = &Sec;
break;
case ELF::SHT_GNU_verdef:
if (dot_gnu_version_d_sec != nullptr) {
// More than one .gnu.version_d section!
EC = object_error::parse_failed;
return;
}
dot_gnu_version_d_sec = &Sec;
break;
case ELF::SHT_GNU_verneed:
if (dot_gnu_version_r_sec != nullptr) {
// More than one .gnu.version_r section!
EC = object_error::parse_failed;
return;
}
dot_gnu_version_r_sec = &Sec;
break;
}
}
@ -668,61 +531,6 @@ ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section) const {
return StringRef(DotShstrtab.data() + Offset);
}
template <class ELFT>
ErrorOr<StringRef> ELFFile<ELFT>::getSymbolVersion(StringRef StrTab,
const Elf_Sym *symb,
bool &IsDefault) const {
// This is a dynamic symbol. Look in the GNU symbol version table.
if (!dot_gnu_version_sec) {
// No version table.
IsDefault = false;
return StringRef("");
}
// Determine the position in the symbol table of this entry.
size_t entry_index =
(reinterpret_cast<uintptr_t>(symb) - DotDynSymSec->sh_offset -
reinterpret_cast<uintptr_t>(base())) /
sizeof(Elf_Sym);
// Get the corresponding version index entry
const Elf_Versym *vs = getEntry<Elf_Versym>(dot_gnu_version_sec, entry_index);
size_t version_index = vs->vs_index & ELF::VERSYM_VERSION;
// Special markers for unversioned symbols.
if (version_index == ELF::VER_NDX_LOCAL ||
version_index == ELF::VER_NDX_GLOBAL) {
IsDefault = false;
return StringRef("");
}
// Lookup this symbol in the version table
LoadVersionMap();
if (version_index >= VersionMap.size() || VersionMap[version_index].isNull())
return object_error::parse_failed;
const VersionMapEntry &entry = VersionMap[version_index];
// Get the version name string
size_t name_offset;
if (entry.isVerdef()) {
// The first Verdaux entry holds the name.
name_offset = entry.getVerdef()->getAux()->vda_name;
} else {
name_offset = entry.getVernaux()->vna_name;
}
// Set IsDefault
if (entry.isVerdef()) {
IsDefault = !(vs->vs_index & ELF::VERSYM_HIDDEN);
} else {
IsDefault = false;
}
if (name_offset >= StrTab.size())
return object_error::parse_failed;
return StringRef(StrTab.data() + name_offset);
}
/// This function returns the hash value for a symbol in the .dynsym section
/// Name of the API remains consistent as specified in the libelf
/// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash

2
llvm/test/Object/corrupt.test
View File

@ -23,7 +23,7 @@ SYMNAME: Error reading file: Invalid data was encountered while parsing the file
RUN: not llvm-readobj %p/Inputs/corrupt-version.elf-x86_64 -dt \
RUN: 2>&1 | FileCheck --check-prefix=VER %s
VER: Error reading file: Invalid data was encountered while parsing the file.
VER: Error reading file: Invalid version entry.
// The file is missing the dynamic string table but has references to it.

233
llvm/tools/llvm-readobj/ELFDumper.cpp
View File

@ -78,6 +78,10 @@ private:
typedef typename ELFO::Elf_Hash Elf_Hash;
typedef typename ELFO::Elf_Ehdr Elf_Ehdr;
typedef typename ELFO::uintX_t uintX_t;
typedef typename ELFO::Elf_Versym Elf_Versym;
typedef typename ELFO::Elf_Verneed Elf_Verneed;
typedef typename ELFO::Elf_Vernaux Elf_Vernaux;
typedef typename ELFO::Elf_Verdef Elf_Verdef;
/// \brief Represents a region described by entries in the .dynamic table.
struct DynRegionInfo {
@ -106,6 +110,12 @@ private:
return make_range(dynamic_table_begin(), dynamic_table_end());
}
StringRef getSymbolVersion(StringRef StrTab, const Elf_Sym *symb,
bool &IsDefault);
void LoadVersionMap();
void LoadVersionNeeds(const Elf_Shdr *ec) const;
void LoadVersionDefs(const Elf_Shdr *sec) const;
const ELFO *Obj;
DynRegionInfo DynRelaRegion;
DynRegionInfo DynamicRegion;
@ -113,6 +123,37 @@ private:
const Elf_Sym *DynSymStart = nullptr;
StringRef SOName;
const Elf_Hash *HashTable = nullptr;
const Elf_Shdr *dot_gnu_version_sec = nullptr; // .gnu.version
const Elf_Shdr *dot_gnu_version_r_sec = nullptr; // .gnu.version_r
const Elf_Shdr *dot_gnu_version_d_sec = nullptr; // .gnu.version_d
// Records for each version index the corresponding Verdef or Vernaux entry.
// This is filled the first time LoadVersionMap() is called.
class VersionMapEntry : public PointerIntPair<const void *, 1> {
public:
// If the integer is 0, this is an Elf_Verdef*.
// If the integer is 1, this is an Elf_Vernaux*.
VersionMapEntry() : PointerIntPair<const void *, 1>(nullptr, 0) {}
VersionMapEntry(const Elf_Verdef *verdef)
: PointerIntPair<const void *, 1>(verdef, 0) {}
VersionMapEntry(const Elf_Vernaux *vernaux)
: PointerIntPair<const void *, 1>(vernaux, 1) {}
bool isNull() const { return getPointer() == nullptr; }
bool isVerdef() const { return !isNull() && getInt() == 0; }
bool isVernaux() const { return !isNull() && getInt() == 1; }
const Elf_Verdef *getVerdef() const {
return isVerdef() ? (const Elf_Verdef *)getPointer() : nullptr;
}
const Elf_Vernaux *getVernaux() const {
return isVernaux() ? (const Elf_Vernaux *)getPointer() : nullptr;
}
};
mutable SmallVector<VersionMapEntry, 16> VersionMap;
public:
std::string getFullSymbolName(const Elf_Sym *Symbol, StringRef StrTable,
bool IsDynamic);
};
template <class T> T errorOrDefault(ErrorOr<T> Val, T Default = T()) {
@ -159,10 +200,145 @@ std::error_code createELFDumper(const object::ObjectFile *Obj,
} // namespace llvm
template <typename ELFO>
static std::string getFullSymbolName(const ELFO &Obj,
const typename ELFO::Elf_Sym *Symbol,
StringRef StrTable, bool IsDynamic) {
// Iterate through the versions needed section, and place each Elf_Vernaux
// in the VersionMap according to its index.
template <class ELFT>
void ELFDumper<ELFT>::LoadVersionNeeds(const Elf_Shdr *sec) const {
unsigned vn_size = sec->sh_size; // Size of section in bytes
unsigned vn_count = sec->sh_info; // Number of Verneed entries
const char *sec_start = (const char *)Obj->base() + sec->sh_offset;
const char *sec_end = sec_start + vn_size;
// The first Verneed entry is at the start of the section.
const char *p = sec_start;
for (unsigned i = 0; i < vn_count; i++) {
if (p + sizeof(Elf_Verneed) > sec_end)
report_fatal_error("Section ended unexpectedly while scanning "
"version needed records.");
const Elf_Verneed *vn = reinterpret_cast<const Elf_Verneed *>(p);
if (vn->vn_version != ELF::VER_NEED_CURRENT)
report_fatal_error("Unexpected verneed version");
// Iterate through the Vernaux entries
const char *paux = p + vn->vn_aux;
for (unsigned j = 0; j < vn->vn_cnt; j++) {
if (paux + sizeof(Elf_Vernaux) > sec_end)
report_fatal_error("Section ended unexpected while scanning auxiliary "
"version needed records.");
const Elf_Vernaux *vna = reinterpret_cast<const Elf_Vernaux *>(paux);
size_t index = vna->vna_other & ELF::VERSYM_VERSION;
if (index >= VersionMap.size())
VersionMap.resize(index + 1);
VersionMap[index] = VersionMapEntry(vna);
paux += vna->vna_next;
}
p += vn->vn_next;
}
}
// Iterate through the version definitions, and place each Elf_Verdef
// in the VersionMap according to its index.
template <class ELFT>
void ELFDumper<ELFT>::LoadVersionDefs(const Elf_Shdr *sec) const {
unsigned vd_size = sec->sh_size; // Size of section in bytes
unsigned vd_count = sec->sh_info; // Number of Verdef entries
const char *sec_start = (const char *)Obj->base() + sec->sh_offset;
const char *sec_end = sec_start + vd_size;
// The first Verdef entry is at the start of the section.
const char *p = sec_start;
for (unsigned i = 0; i < vd_count; i++) {
if (p + sizeof(Elf_Verdef) > sec_end)
report_fatal_error("Section ended unexpectedly while scanning "
"version definitions.");
const Elf_Verdef *vd = reinterpret_cast<const Elf_Verdef *>(p);
if (vd->vd_version != ELF::VER_DEF_CURRENT)
report_fatal_error("Unexpected verdef version");
size_t index = vd->vd_ndx & ELF::VERSYM_VERSION;
if (index >= VersionMap.size())
VersionMap.resize(index + 1);
VersionMap[index] = VersionMapEntry(vd);
p += vd->vd_next;
}
}
template <class ELFT> void ELFDumper<ELFT>::LoadVersionMap() {
// If there is no dynamic symtab or version table, there is nothing to do.
if (!DynSymStart || !dot_gnu_version_sec)
return;
// Has the VersionMap already been loaded?
if (VersionMap.size() > 0)
return;
// The first two version indexes are reserved.
// Index 0 is LOCAL, index 1 is GLOBAL.
VersionMap.push_back(VersionMapEntry());
VersionMap.push_back(VersionMapEntry());
if (dot_gnu_version_d_sec)
LoadVersionDefs(dot_gnu_version_d_sec);
if (dot_gnu_version_r_sec)
LoadVersionNeeds(dot_gnu_version_r_sec);
}
template <typename ELFT>
StringRef ELFDumper<ELFT>::getSymbolVersion(StringRef StrTab,
const Elf_Sym *symb,
bool &IsDefault) {
// This is a dynamic symbol. Look in the GNU symbol version table.
if (!dot_gnu_version_sec) {
// No version table.
IsDefault = false;
return StringRef("");
}
// Determine the position in the symbol table of this entry.
size_t entry_index = (reinterpret_cast<uintptr_t>(symb) -
reinterpret_cast<uintptr_t>(DynSymStart)) /
sizeof(Elf_Sym);
// Get the corresponding version index entry
const Elf_Versym *vs =
Obj->template getEntry<Elf_Versym>(dot_gnu_version_sec, entry_index);
size_t version_index = vs->vs_index & ELF::VERSYM_VERSION;
// Special markers for unversioned symbols.
if (version_index == ELF::VER_NDX_LOCAL ||
version_index == ELF::VER_NDX_GLOBAL) {
IsDefault = false;
return StringRef("");
}
// Lookup this symbol in the version table
LoadVersionMap();
if (version_index >= VersionMap.size() || VersionMap[version_index].isNull())
reportError("Invalid version entry");
const VersionMapEntry &entry = VersionMap[version_index];
// Get the version name string
size_t name_offset;
if (entry.isVerdef()) {
// The first Verdaux entry holds the name.
name_offset = entry.getVerdef()->getAux()->vda_name;
} else {
name_offset = entry.getVernaux()->vna_name;
}
// Set IsDefault
if (entry.isVerdef()) {
IsDefault = !(vs->vs_index & ELF::VERSYM_HIDDEN);
} else {
IsDefault = false;
}
if (name_offset >= StrTab.size())
reportError("Invalid string offset");
return StringRef(StrTab.data() + name_offset);
}
template <typename ELFT>
std::string ELFDumper<ELFT>::getFullSymbolName(const Elf_Sym *Symbol,
StringRef StrTable,
bool IsDynamic) {
StringRef SymbolName = errorOrDefault(Symbol->getName(StrTable));
if (!IsDynamic)
return SymbolName;
@ -170,13 +346,9 @@ static std::string getFullSymbolName(const ELFO &Obj,
std::string FullSymbolName(SymbolName);
bool IsDefault;
ErrorOr<StringRef> Version =
Obj.getSymbolVersion(StrTable, &*Symbol, IsDefault);
if (Version) {
FullSymbolName += (IsDefault ? "@@" : "@");
FullSymbolName += *Version;
} else
error(Version.getError());
StringRef Version = getSymbolVersion(StrTable, &*Symbol, IsDefault);
FullSymbolName += (IsDefault ? "@@" : "@");
FullSymbolName += Version;
return FullSymbolName;
}
@ -671,6 +843,26 @@ ELFDumper<ELFT>::ELFDumper(const ELFFile<ELFT> *Obj, StreamWriter &Writer)
DynamicStringTable = StringRef(StringTableBegin, StringTableSize);
if (SONameOffset)
SOName = getDynamicString(SONameOffset);
for (const Elf_Shdr &Sec : Obj->sections()) {
switch (Sec.sh_type) {
case ELF::SHT_GNU_versym:
if (dot_gnu_version_sec != nullptr)
reportError("Multiple SHT_GNU_versym");
dot_gnu_version_sec = &Sec;
break;
case ELF::SHT_GNU_verdef:
if (dot_gnu_version_d_sec != nullptr)
reportError("Multiple SHT_GNU_verdef");
dot_gnu_version_d_sec = &Sec;
break;
case ELF::SHT_GNU_verneed:
if (dot_gnu_version_r_sec != nullptr)
reportError("Multilpe SHT_GNU_verneed");
dot_gnu_version_r_sec = &Sec;
break;
}
}
}
template <typename ELFT>
@ -946,8 +1138,7 @@ void ELFDumper<ELFT>::printSymbol(const Elf_Sym *Symbol, StringRef StrTable,
unsigned SectionIndex = 0;
StringRef SectionName;
getSectionNameIndex(*Obj, Symbol, SectionName, SectionIndex);
std::string FullSymbolName =
getFullSymbolName(*Obj, Symbol, StrTable, IsDynamic);
std::string FullSymbolName = getFullSymbolName(Symbol, StrTable, IsDynamic);
DictScope D(W, "Symbol");
W.printNumber("Name", FullSymbolName, Symbol->st_name);
@ -1346,12 +1537,14 @@ public:
typedef typename ELFO::Elf_Rel Elf_Rel;
typedef typename ELFO::Elf_Rela Elf_Rela;
MipsGOTParser(const ELFO *Obj, Elf_Dyn_Range DynTable, StreamWriter &W);
MipsGOTParser(ELFDumper<ELFT> *Dumper, const ELFO *Obj,
Elf_Dyn_Range DynTable, StreamWriter &W);
void parseGOT();
void parsePLT();
private:
ELFDumper<ELFT> *Dumper;
const ELFO *Obj;
StreamWriter &W;
llvm::Optional<uint64_t> DtPltGot;
@ -1377,9 +1570,9 @@ private:
}
template <class ELFT>
MipsGOTParser<ELFT>::MipsGOTParser(const ELFO *Obj, Elf_Dyn_Range DynTable,
StreamWriter &W)
: Obj(Obj), W(W) {
MipsGOTParser<ELFT>::MipsGOTParser(ELFDumper<ELFT> *Dumper, const ELFO *Obj,
Elf_Dyn_Range DynTable, StreamWriter &W)
: Dumper(Dumper), Obj(Obj), W(W) {
for (const auto &Entry : DynTable) {
switch (Entry.getTag()) {
case ELF::DT_PLTGOT:
@ -1606,7 +1799,7 @@ void MipsGOTParser<ELFT>::printGlobalGotEntry(
W.printHex("Section", SectionName, SectionIndex);
std::string FullSymbolName =
getFullSymbolName(*Obj, Sym, StrTable, IsDynamic);
Dumper->getFullSymbolName(Sym, StrTable, IsDynamic);
W.printNumber("Name", FullSymbolName, Sym->st_name);
}
@ -1638,7 +1831,7 @@ void MipsGOTParser<ELFT>::printPLTEntry(uint64_t PLTAddr,
getSectionNameIndex(*Obj, Sym, SectionName, SectionIndex);
W.printHex("Section", SectionName, SectionIndex);
std::string FullSymbolName = getFullSymbolName(*Obj, Sym, StrTable, true);
std::string FullSymbolName = Dumper->getFullSymbolName(Sym, StrTable, true);
W.printNumber("Name", FullSymbolName, Sym->st_name);
}
@ -1648,7 +1841,7 @@ template <class ELFT> void ELFDumper<ELFT>::printMipsPLTGOT() {
return;
}
MipsGOTParser<ELFT> GOTParser(Obj, dynamic_table(), W);
MipsGOTParser<ELFT> GOTParser(this, Obj, dynamic_table(), W);
GOTParser.parseGOT();
GOTParser.parsePLT();
}

4
llvm/tools/llvm-readobj/llvm-readobj.cpp
View File

@ -191,7 +191,7 @@ namespace opts {
namespace llvm {
void reportError(Twine Msg) {
outs() << Msg << "\n";
outs() << "\nError reading file: " << Msg << ".\n";
outs().flush();
exit(1);
}
@ -200,7 +200,7 @@ void error(std::error_code EC) {
if (!EC)
return;
reportError(Twine("\nError reading file: ") + EC.message() + ".");
reportError(EC.message());
}
bool relocAddressLess(RelocationRef a, RelocationRef b) {