-//===- lib/MC/ELFObjectWriter.cpp - ELF File Writer -------------------===//
+//===- lib/MC/ELFObjectWriter.cpp - ELF File Writer -----------------------===//
//
// The LLVM Compiler Infrastructure
//
//===----------------------------------------------------------------------===//
#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"
// 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();
}
};
/// The target specific ELF writer instance.
- llvm::OwningPtr<MCELFObjectTargetWriter> TargetObjectWriter;
+ std::unique_ptr<MCELFObjectTargetWriter> TargetObjectWriter;
SmallPtrSet<const MCSymbol *, 16> UsedInReloc;
SmallPtrSet<const MCSymbol *, 16> WeakrefUsedInReloc;
/// @{
SmallString<256> StringTable;
+ std::vector<uint64_t> FileSymbolData;
std::vector<ELFSymbolData> LocalSymbolData;
std::vector<ELFSymbolData> ExternalSymbolData;
std::vector<ELFSymbolData> UndefinedSymbolData;
const MCSymbol *undefinedExplicitRelSym(const MCValue &Target,
const MCFixup &Fixup,
bool IsPCRel) const {
- return TargetObjectWriter->undefinedExplicitRelSym(Target, Fixup, IsPCRel);
+ return TargetObjectWriter->undefinedExplicitRelSym(Target, Fixup,
+ IsPCRel);
}
bool is64Bit() const { return TargetObjectWriter->is64Bit(); }
raw_ostream &_OS, bool IsLittleEndian)
: MCObjectWriter(_OS, IsLittleEndian),
TargetObjectWriter(MOTW),
- NeedsGOT(false), NeedsSymtabShndx(false){
+ NeedsGOT(false), NeedsSymtabShndx(false) {
}
virtual ~ELFObjectWriter();
const MCAsmLayout &Layout,
const SectionIndexMapTy &SectionIndexMap);
- virtual void RecordRelocation(const MCAssembler &Asm,
- const MCAsmLayout &Layout,
- const MCFragment *Fragment,
- const MCFixup &Fixup,
- MCValue Target, uint64_t &FixedValue);
+ void RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
+ const MCFragment *Fragment, const MCFixup &Fixup,
+ MCValue Target, uint64_t &FixedValue) override;
uint64_t getSymbolIndexInSymbolTable(const MCAssembler &Asm,
const MCSymbol *S);
/// \param RevGroupMap - Maps a signature symbol to the group section.
/// \param NumRegularSections - Number of non-relocation sections.
void ComputeSymbolTable(MCAssembler &Asm,
+ const MCAsmLayout &Layout,
const SectionIndexMapTy &SectionIndexMap,
RevGroupMapTy RevGroupMap,
unsigned NumRegularSections);
SectionIndexMapTy &SectionIndexMap,
const RelMapTy &RelMap);
- virtual void ExecutePostLayoutBinding(MCAssembler &Asm,
- const MCAsmLayout &Layout);
+ void ExecutePostLayoutBinding(MCAssembler &Asm,
+ const MCAsmLayout &Layout) override;
void WriteSectionHeader(MCAssembler &Asm, const GroupMapTy &GroupMap,
const MCAsmLayout &Layout,
MCDataFragment *F,
const MCSectionData *SD);
- virtual bool
+ bool
IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
const MCSymbolData &DataA,
const MCFragment &FB,
bool InSet,
- bool IsPCRel) const;
+ bool IsPCRel) const override;
- virtual void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
+ void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout) override;
void WriteSection(MCAssembler &Asm,
const SectionIndexMapTy &SectionIndexMap,
uint32_t GroupSymbolIndex,
}
}
-uint64_t ELFObjectWriter::SymbolValue(MCSymbolData &Data,
+uint64_t ELFObjectWriter::SymbolValue(MCSymbolData &OrigData,
const MCAsmLayout &Layout) {
- if (Data.isCommon() && Data.isExternal())
- return Data.getCommonAlignment();
-
- const MCSymbol &Symbol = Data.getSymbol();
-
- if (Symbol.isAbsolute() && Symbol.isVariable()) {
- if (const MCExpr *Value = Symbol.getVariableValue()) {
- int64_t IntValue;
- if (Value->EvaluateAsAbsolute(IntValue, Layout))
- return (uint64_t)IntValue;
- }
+ MCSymbolData *Data = &OrigData;
+ if (Data->isCommon() && Data->isExternal())
+ return Data->getCommonAlignment();
+
+ const MCSymbol *Symbol = &Data->getSymbol();
+
+ uint64_t Res = 0;
+ if (Symbol->isVariable()) {
+ const MCExpr *Expr = Symbol->getVariableValue();
+ MCValue Value;
+ if (!Expr->EvaluateAsRelocatable(Value, &Layout))
+ return 0;
+ if (Value.getSymB())
+ return 0;
+ Res = Value.getConstant();
+
+ const MCSymbolRefExpr *A = Value.getSymA();
+ if (!A)
+ return Res;
+
+ Symbol = &A->getSymbol();
+ Data = &Layout.getAssembler().getSymbolData(*Symbol);
}
- if (!Symbol.isInSection())
+ if (!Symbol->isInSection())
return 0;
+ if (!Data->getFragment())
+ return 0;
- if (Data.getFragment()) {
- if (Data.getFlags() & ELF_Other_ThumbFunc)
- return Layout.getSymbolOffset(&Data)+1;
- else
- return Layout.getSymbolOffset(&Data);
- }
+ Res += Layout.getSymbolOffset(Data);
+ if (Data->getFlags() & ELF_Other_ThumbFunc)
+ ++Res;
- return 0;
+ return Res;
}
void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
}
}
+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;
- uint64_t Value = SymbolValue(Data, Layout);
+ // 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(OrigData, Layout);
uint64_t Size = 0;
assert(!(Data.isCommon() && !Data.isExternal()));
// 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);
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);
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;
if (!Symbol.isVariable() && Symbol.isUndefined() && !IsGlobal)
return false;
- if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
- return false;
-
if (Symbol.isTemporary())
return false;
}
}
-void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm,
- const SectionIndexMapTy &SectionIndexMap,
- RevGroupMapTy RevGroupMap,
- unsigned NumRegularSections) {
+void
+ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm, const MCAsmLayout &Layout,
+ const SectionIndexMapTy &SectionIndexMap,
+ RevGroupMapTy RevGroupMap,
+ unsigned NumRegularSections) {
// FIXME: Is this the correct place to do this?
// FIXME: Why is an undefined reference to _GLOBAL_OFFSET_TABLE_ needed?
if (NeedsGOT) {
// 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) {
ELFSymbolData MSD;
MSD.SymbolData = it;
- const MCSymbol &RefSymbol = Symbol.AliasedSymbol();
+ const MCSymbol *BaseSymbol = Symbol.getBaseSymbol(Layout);
// Undefined symbols are global, but this is the first place we
// are able to set it.
bool Local = isLocal(*it, isSignature, Used);
if (!Local && MCELF::GetBinding(*it) == ELF::STB_LOCAL) {
- MCSymbolData &SD = Asm.getSymbolData(RefSymbol);
+ assert(BaseSymbol);
+ MCSymbolData &SD = Asm.getSymbolData(*BaseSymbol);
MCELF::SetBinding(*it, ELF::STB_GLOBAL);
MCELF::SetBinding(SD, ELF::STB_GLOBAL);
}
- if (RefSymbol.isUndefined() && !Used && WeakrefUsed)
- MCELF::SetBinding(*it, ELF::STB_WEAK);
-
- if (it->isCommon()) {
+ if (!BaseSymbol) {
+ MSD.SectionIndex = ELF::SHN_ABS;
+ } else if (it->isCommon()) {
assert(!Local);
MSD.SectionIndex = ELF::SHN_COMMON;
- } else if (Symbol.isAbsolute() || RefSymbol.isVariable()) {
- MSD.SectionIndex = ELF::SHN_ABS;
- } else if (RefSymbol.isUndefined()) {
+ } else if (BaseSymbol->isUndefined()) {
if (isSignature && !Used)
MSD.SectionIndex = SectionIndexMap.lookup(RevGroupMap[&Symbol]);
else
MSD.SectionIndex = ELF::SHN_UNDEF;
+ if (!Used && WeakrefUsed)
+ MCELF::SetBinding(*it, ELF::STB_WEAK);
} else {
const MCSectionELF &Section =
- static_cast<const MCSectionELF&>(RefSymbol.getSection());
+ static_cast<const MCSectionELF&>(BaseSymbol->getSection());
MSD.SectionIndex = SectionIndexMap.lookup(&Section);
if (MSD.SectionIndex >= ELF::SHN_LORESERVE)
NeedsSymtabShndx = true;
// 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);
// 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;
}
ELF::SHF_EXECINSTR | ELF::SHF_ALLOC,
SectionKind::getText()));
} else if (SecName.startswith(".ARM.exidx")) {
- sh_link = SectionIndexMap.lookup(
- Asm.getContext().getELFSection(SecName.substr(sizeof(".ARM.exidx") - 1),
- ELF::SHT_PROGBITS,
- ELF::SHF_EXECINSTR | ELF::SHF_ALLOC,
- SectionKind::getText()));
+ 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));
}
}
unsigned NumRegularSections = NumUserSections + NumIndexedSections;
// Compute symbol table information.
- ComputeSymbolTable(Asm, SectionIndexMap, RevGroupMap, NumRegularSections);
-
+ ComputeSymbolTable(Asm, Layout, SectionIndexMap, RevGroupMap,
+ NumRegularSections);
WriteRelocations(Asm, const_cast<MCAsmLayout&>(Layout), RelMap);
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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