-//===- lib/MC/ELFObjectWriter.cpp - ELF File Writer -------------------===//
+//===- lib/MC/ELFObjectWriter.cpp - ELF File Writer -----------------------===//
//
// The LLVM Compiler Infrastructure
//
//
//===----------------------------------------------------------------------===//
-#include "MCELF.h"
+#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
-#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
-#include "llvm/MC/MCELFObjectWriter.h"
+#include "llvm/MC/MCELF.h"
#include "llvm/MC/MCELFSymbolFlags.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCFixupKindInfo.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/Debug.h"
-#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ELF.h"
-
+#include "llvm/Support/ErrorHandling.h"
#include <vector>
using namespace llvm;
// Support lexicographic sorting.
bool operator<(const ELFSymbolData &RHS) const {
- if (MCELF::GetType(*SymbolData) == ELF::STT_FILE)
- return true;
- if (MCELF::GetType(*RHS.SymbolData) == ELF::STT_FILE)
- return false;
return SymbolData->getSymbol().getName() <
RHS.SymbolData->getSymbol().getName();
}
/// @{
SmallString<256> StringTable;
+ std::vector<uint64_t> FileSymbolData;
std::vector<ELFSymbolData> LocalSymbolData;
std::vector<ELFSymbolData> ExternalSymbolData;
std::vector<ELFSymbolData> UndefinedSymbolData;
bool IsPCRel) const {
return TargetObjectWriter->ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
}
+ const MCSymbol *undefinedExplicitRelSym(const MCValue &Target,
+ const MCFixup &Fixup,
+ bool IsPCRel) const {
+ return TargetObjectWriter->undefinedExplicitRelSym(Target, Fixup,
+ IsPCRel);
+ }
bool is64Bit() const { return TargetObjectWriter->is64Bit(); }
bool hasRelocationAddend() const {
return TargetObjectWriter->hasRelocationAddend();
}
- unsigned getEFlags() const {
- return TargetObjectWriter->getEFlags();
- }
unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
bool IsPCRel, bool IsRelocWithSymbol,
int64_t Addend) const {
IsRelocWithSymbol, Addend);
}
-
public:
ELFObjectWriter(MCELFObjectTargetWriter *MOTW,
raw_ostream &_OS, bool IsLittleEndian)
: MCObjectWriter(_OS, IsLittleEndian),
TargetObjectWriter(MOTW),
- NeedsGOT(false), NeedsSymtabShndx(false){
+ NeedsGOT(false), NeedsSymtabShndx(false) {
}
virtual ~ELFObjectWriter();
void String8(MCDataFragment &F, uint8_t Value) {
char buf[1];
buf[0] = Value;
- F.getContents() += StringRef(buf, 1);
+ F.getContents().append(&buf[0], &buf[1]);
}
void String16(MCDataFragment &F, uint16_t Value) {
StringLE16(buf, Value);
else
StringBE16(buf, Value);
- F.getContents() += StringRef(buf, 2);
+ F.getContents().append(&buf[0], &buf[2]);
}
void String32(MCDataFragment &F, uint32_t Value) {
StringLE32(buf, Value);
else
StringBE32(buf, Value);
- F.getContents() += StringRef(buf, 4);
+ F.getContents().append(&buf[0], &buf[4]);
}
void String64(MCDataFragment &F, uint64_t Value) {
StringLE64(buf, Value);
else
StringBE64(buf, Value);
- F.getContents() += StringRef(buf, 8);
+ F.getContents().append(&buf[0], &buf[8]);
}
- void WriteHeader(uint64_t SectionDataSize,
+ void WriteHeader(const MCAssembler &Asm,
+ uint64_t SectionDataSize,
unsigned NumberOfSections);
void WriteSymbolEntry(MCDataFragment *SymtabF,
/// ComputeSymbolTable - Compute the symbol table data
///
- /// \param StringTable [out] - The string table data.
- /// \param StringIndexMap [out] - Map from symbol names to offsets in the
- /// string table.
+ /// \param Asm - The assembler.
+ /// \param SectionIndexMap - Maps a section to its index.
+ /// \param RevGroupMap - Maps a signature symbol to the group section.
+ /// \param NumRegularSections - Number of non-relocation sections.
void ComputeSymbolTable(MCAssembler &Asm,
const SectionIndexMapTy &SectionIndexMap,
RevGroupMapTy RevGroupMap,
{}
// Emit the ELF header.
-void ELFObjectWriter::WriteHeader(uint64_t SectionDataSize,
+void ELFObjectWriter::WriteHeader(const MCAssembler &Asm,
+ uint64_t SectionDataSize,
unsigned NumberOfSections) {
// ELF Header
// ----------
sizeof(ELF::Elf32_Ehdr))); // e_shoff = sec hdr table off in bytes
// e_flags = whatever the target wants
- Write32(getEFlags());
+ Write32(Asm.getELFHeaderEFlags());
// e_ehsize = ELF header size
Write16(is64Bit() ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr));
}
}
+static uint8_t mergeTypeForSet(uint8_t origType, uint8_t newType) {
+ uint8_t Type = newType;
+
+ // Propagation rules:
+ // IFUNC > FUNC > OBJECT > NOTYPE
+ // TLS_OBJECT > OBJECT > NOTYPE
+ //
+ // dont let the new type degrade the old type
+ switch (origType) {
+ default:
+ break;
+ case ELF::STT_GNU_IFUNC:
+ if (Type == ELF::STT_FUNC || Type == ELF::STT_OBJECT ||
+ Type == ELF::STT_NOTYPE || Type == ELF::STT_TLS)
+ Type = ELF::STT_GNU_IFUNC;
+ break;
+ case ELF::STT_FUNC:
+ if (Type == ELF::STT_OBJECT || Type == ELF::STT_NOTYPE ||
+ Type == ELF::STT_TLS)
+ Type = ELF::STT_FUNC;
+ break;
+ case ELF::STT_OBJECT:
+ if (Type == ELF::STT_NOTYPE)
+ Type = ELF::STT_OBJECT;
+ break;
+ case ELF::STT_TLS:
+ if (Type == ELF::STT_OBJECT || Type == ELF::STT_NOTYPE ||
+ Type == ELF::STT_GNU_IFUNC || Type == ELF::STT_FUNC)
+ Type = ELF::STT_TLS;
+ break;
+ }
+
+ return Type;
+}
+
void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF,
MCDataFragment *ShndxF,
ELFSymbolData &MSD,
bool IsReserved = Data.isCommon() || Data.getSymbol().isAbsolute() ||
Data.getSymbol().isVariable();
+ // Binding and Type share the same byte as upper and lower nibbles
uint8_t Binding = MCELF::GetBinding(OrigData);
- uint8_t Visibility = MCELF::GetVisibility(OrigData);
- uint8_t Type = MCELF::GetType(Data);
-
+ uint8_t Type = mergeTypeForSet(MCELF::GetType(OrigData), MCELF::GetType(Data));
uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift);
- uint8_t Other = Visibility;
+
+ // Other and Visibility share the same byte with Visibility using the lower
+ // 2 bits
+ uint8_t Visibility = MCELF::GetVisibility(OrigData);
+ uint8_t Other = MCELF::getOther(OrigData) << (ELF_STO_Shift - ELF_STV_Shift);
+ Other |= Visibility;
uint64_t Value = SymbolValue(Data, Layout);
uint64_t Size = 0;
// The first entry is the undefined symbol entry.
WriteSymbolEntry(SymtabF, ShndxF, 0, 0, 0, 0, 0, 0, false);
+ for (unsigned i = 0, e = FileSymbolData.size(); i != e; ++i) {
+ WriteSymbolEntry(SymtabF, ShndxF, FileSymbolData[i],
+ ELF::STT_FILE | ELF::STB_LOCAL, 0, 0,
+ ELF::STV_DEFAULT, ELF::SHN_ABS, true);
+ }
+
// Write the symbol table entries.
- LastLocalSymbolIndex = LocalSymbolData.size() + 1;
+ LastLocalSymbolIndex = FileSymbolData.size() + LocalSymbolData.size() + 1;
+
for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) {
ELFSymbolData &MSD = LocalSymbolData[i];
WriteSymbol(SymtabF, ShndxF, MSD, Layout);
if (ASymbol.isUndefined()) {
if (Renamed)
return Renamed;
- return &ASymbol;
+ return undefinedExplicitRelSym(Target, Fixup, IsPCRel);
}
if (SD.isExternal()) {
MCSymbolData &SDB = Asm.getSymbolData(SymbolB);
IsPCRel = true;
+ if (!SDB.getFragment())
+ Asm.getContext().FatalError(
+ Fixup.getLoc(),
+ Twine("symbol '") + SymbolB.getName() +
+ "' can not be undefined in a subtraction expression");
+
// Offset of the symbol in the section
int64_t a = Layout.getSymbolOffset(&SDB);
MCSymbolData &SD = Asm.getSymbolData(ASymbol);
MCFragment *F = SD.getFragment();
- Index = F->getParent()->getOrdinal() + 1;
-
- // Offset of the symbol in the section
- Value += Layout.getSymbolOffset(&SD);
+ if (F) {
+ Index = F->getParent()->getOrdinal() + 1;
+ // Offset of the symbol in the section
+ Value += Layout.getSymbolOffset(&SD);
+ } else {
+ Index = 0;
+ }
} else {
if (Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
WeakrefUsedInReloc.insert(RelocSymbol);
Index = -1;
}
Addend = Value;
- // Compensate for the addend on i386.
- if (is64Bit())
+ if (hasRelocationAddend())
Value = 0;
}
uint64_t RelocOffset = Layout.getFragmentOffset(Fragment) +
Fixup.getOffset();
- // FIXME: no tests cover this. Is adjustFixupOffset dead code?
- TargetObjectWriter->adjustFixupOffset(Fixup, RelocOffset);
-
if (!hasRelocationAddend())
Addend = 0;
// FIXME: Is this the correct place to do this?
// FIXME: Why is an undefined reference to _GLOBAL_OFFSET_TABLE_ needed?
if (NeedsGOT) {
- llvm::StringRef Name = "_GLOBAL_OFFSET_TABLE_";
+ StringRef Name = "_GLOBAL_OFFSET_TABLE_";
MCSymbol *Sym = Asm.getContext().GetOrCreateSymbol(Name);
MCSymbolData &Data = Asm.getOrCreateSymbolData(*Sym);
Data.setExternal(true);
// FIXME: We could optimize suffixes in strtab in the same way we
// optimize them in shstrtab.
+ for (MCAssembler::const_file_name_iterator it = Asm.file_names_begin(),
+ ie = Asm.file_names_end();
+ it != ie;
+ ++it) {
+ StringRef Name = *it;
+ uint64_t &Entry = StringIndexMap[Name];
+ if (!Entry) {
+ Entry = StringTable.size();
+ StringTable += Name;
+ StringTable += '\x00';
+ }
+ FileSymbolData.push_back(Entry);
+ }
+
// Add the data for the symbols.
for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
ie = Asm.symbol_end(); it != ie; ++it) {
// Set the symbol indices. Local symbols must come before all other
// symbols with non-local bindings.
- unsigned Index = 1;
+ unsigned Index = FileSymbolData.size() + 1;
for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
LocalSymbolData[i].SymbolData->setIndex(Index++);
for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
UndefinedSymbolData[i].SymbolData->setIndex(Index++);
- if (NumRegularSections > ELF::SHN_LORESERVE)
+ if (Index >= ELF::SHN_LORESERVE)
NeedsSymtabShndx = true;
}
else
EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel);
+ unsigned Flags = 0;
+ StringRef Group = "";
+ if (Section.getFlags() & ELF::SHF_GROUP) {
+ Flags = ELF::SHF_GROUP;
+ Group = Section.getGroup()->getName();
+ }
+
const MCSectionELF *RelaSection =
Ctx.getELFSection(RelaSectionName, hasRelocationAddend() ?
- ELF::SHT_RELA : ELF::SHT_REL, 0,
+ ELF::SHT_RELA : ELF::SHT_REL, Flags,
SectionKind::getReadOnly(),
- EntrySize, "");
+ EntrySize, Group);
RelMap[&Section] = RelaSection;
Asm.getOrCreateSectionData(*RelaSection);
}
else if (entry.Index < 0)
entry.Index = getSymbolIndexInSymbolTable(Asm, entry.Symbol);
else
- entry.Index += LocalSymbolData.size();
+ entry.Index += FileSymbolData.size() + LocalSymbolData.size();
if (is64Bit()) {
String64(*F, entry.r_offset);
if (TargetObjectWriter->isN64()) {
}
}
-static int compareBySuffix(const void *a, const void *b) {
- const MCSectionELF *secA = *static_cast<const MCSectionELF* const *>(a);
- const MCSectionELF *secB = *static_cast<const MCSectionELF* const *>(b);
- const StringRef &NameA = secA->getSectionName();
- const StringRef &NameB = secB->getSectionName();
+static int compareBySuffix(const MCSectionELF *const *a,
+ const MCSectionELF *const *b) {
+ const StringRef &NameA = (*a)->getSectionName();
+ const StringRef &NameB = (*b)->getSectionName();
const unsigned sizeA = NameA.size();
const unsigned sizeB = NameB.size();
const unsigned len = std::min(sizeA, sizeB);
// The first entry of a string table holds a null character so skip
// section 0.
uint64_t Index = 1;
- F->getContents() += '\x00';
+ F->getContents().push_back('\x00');
for (unsigned int I = 0, E = Sections.size(); I != E; ++I) {
const MCSectionELF &Section = *Sections[I];
SectionStringTableIndex[&Section] = Index;
Index += Name.size() + 1;
- F->getContents() += Name;
- F->getContents() += '\x00';
+ F->getContents().append(Name.begin(), Name.end());
+ F->getContents().push_back('\x00');
}
}
// Remove ".rel" and ".rela" prefixes.
unsigned SecNameLen = (Section.getType() == ELF::SHT_REL) ? 4 : 5;
StringRef SectionName = Section.getSectionName().substr(SecNameLen);
+ StringRef GroupName =
+ Section.getGroup() ? Section.getGroup()->getName() : "";
- InfoSection = Asm.getContext().getELFSection(SectionName,
- ELF::SHT_PROGBITS, 0,
- SectionKind::getReadOnly());
+ InfoSection = Asm.getContext().getELFSection(SectionName, ELF::SHT_PROGBITS,
+ 0, SectionKind::getReadOnly(),
+ 0, GroupName);
sh_info = SectionIndexMap.lookup(InfoSection);
break;
}
case ELF::SHT_FINI_ARRAY:
case ELF::SHT_PREINIT_ARRAY:
case ELF::SHT_X86_64_UNWIND:
+ case ELF::SHT_MIPS_REGINFO:
+ case ELF::SHT_MIPS_OPTIONS:
// Nothing to do.
break;
break;
}
+ if (TargetObjectWriter->getEMachine() == ELF::EM_ARM &&
+ Section.getType() == ELF::SHT_ARM_EXIDX) {
+ StringRef SecName(Section.getSectionName());
+ if (SecName == ".ARM.exidx") {
+ sh_link = SectionIndexMap.lookup(
+ Asm.getContext().getELFSection(".text",
+ ELF::SHT_PROGBITS,
+ ELF::SHF_EXECINSTR | ELF::SHF_ALLOC,
+ SectionKind::getText()));
+ } else if (SecName.startswith(".ARM.exidx")) {
+ StringRef GroupName =
+ Section.getGroup() ? Section.getGroup()->getName() : "";
+ sh_link = SectionIndexMap.lookup(Asm.getContext().getELFSection(
+ SecName.substr(sizeof(".ARM.exidx") - 1), ELF::SHT_PROGBITS,
+ ELF::SHF_EXECINSTR | ELF::SHF_ALLOC, SectionKind::getText(), 0,
+ GroupName));
+ }
+ }
+
WriteSecHdrEntry(SectionStringTableIndex[&Section], Section.getType(),
Section.getFlags(), 0, Offset, Size, sh_link, sh_info,
Alignment, Section.getEntrySize());
++i) {
const MCFragment &F = *i;
assert(F.getKind() == MCFragment::FT_Data);
- WriteBytes(cast<MCDataFragment>(F).getContents().str());
+ WriteBytes(cast<MCDataFragment>(F).getContents());
}
} else {
Asm.writeSectionData(&SD, Layout);
}
// Write out the ELF header ...
- WriteHeader(SectionHeaderOffset, NumSections + 1);
+ WriteHeader(Asm, SectionHeaderOffset, NumSections + 1);
// ... then the regular sections ...
// + because of .shstrtab
const MCFragment &FB,
bool InSet,
bool IsPCRel) const {
- if (DataA.getFlags() & ELF_STB_Weak)
+ if (DataA.getFlags() & ELF_STB_Weak || MCELF::GetType(DataA) == ELF::STT_GNU_IFUNC)
return false;
return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
Asm, DataA, FB,InSet, IsPCRel);
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