//===----------------------------------------------------------------------===//
#include "llvm/MC/ELFObjectWriter.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/Twine.h"
SD.setFlags(OtherFlags | (Binding << ELF_STB_Shift));
}
+static unsigned GetVisibility(MCSymbolData &SD) {
+ unsigned Visibility =
+ (SD.getFlags() & (0xf << ELF_STV_Shift)) >> ELF_STV_Shift;
+ assert(Visibility == ELF::STV_DEFAULT || Visibility == ELF::STV_INTERNAL ||
+ Visibility == ELF::STV_HIDDEN || Visibility == ELF::STV_PROTECTED);
+ return Visibility;
+}
+
+static bool isFixupKindX86PCRel(unsigned Kind) {
+ switch (Kind) {
+ default:
+ return false;
+ case X86::reloc_pcrel_1byte:
+ case X86::reloc_pcrel_4byte:
+ case X86::reloc_riprel_4byte:
+ case X86::reloc_riprel_4byte_movq_load:
+ return true;
+ }
+}
+
+static bool RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant) {
+ switch (Variant) {
+ default:
+ return false;
+ case MCSymbolRefExpr::VK_GOT:
+ case MCSymbolRefExpr::VK_PLT:
+ case MCSymbolRefExpr::VK_GOTPCREL:
+ case MCSymbolRefExpr::VK_TPOFF:
+ case MCSymbolRefExpr::VK_TLSGD:
+ case MCSymbolRefExpr::VK_GOTTPOFF:
+ case MCSymbolRefExpr::VK_INDNTPOFF:
+ case MCSymbolRefExpr::VK_NTPOFF:
+ case MCSymbolRefExpr::VK_GOTNTPOFF:
+ case MCSymbolRefExpr::VK_TLSLDM:
+ case MCSymbolRefExpr::VK_DTPOFF:
+ case MCSymbolRefExpr::VK_TLSLD:
+ return true;
+ }
+}
+
namespace {
class ELFObjectWriterImpl {
- static bool isFixupKindX86PCRel(unsigned Kind) {
- switch (Kind) {
- default:
- return false;
- case X86::reloc_pcrel_1byte:
- case X86::reloc_pcrel_4byte:
- case X86::reloc_riprel_4byte:
- case X86::reloc_riprel_4byte_movq_load:
- return true;
- }
- }
-
/*static bool isFixupKindX86RIPRel(unsigned Kind) {
return Kind == X86::reloc_riprel_4byte ||
Kind == X86::reloc_riprel_4byte_movq_load;
struct ELFRelocationEntry {
// Make these big enough for both 32-bit and 64-bit
uint64_t r_offset;
- uint64_t r_info;
+ int Index;
+ unsigned Type;
+ const MCSymbol *Symbol;
uint64_t r_addend;
// Support lexicographic sorting.
}
};
+ SmallPtrSet<const MCSymbol *, 16> UsedInReloc;
+ SmallPtrSet<const MCSymbol *, 16> WeakrefUsedInReloc;
+ DenseMap<const MCSymbol *, const MCSymbol *> Renames;
+
llvm::DenseMap<const MCSectionData*,
std::vector<ELFRelocationEntry> > Relocations;
DenseMap<const MCSection*, uint64_t> SectionStringTableIndex;
/// @}
+ int NumRegularSections;
+
+ bool NeedsGOT;
+
+ bool NeedsSymtabShndx;
+
ELFObjectWriter *Writer;
raw_ostream &OS;
Triple::OSType OSType;
+ uint16_t EMachine;
+
// This holds the symbol table index of the last local symbol.
unsigned LastLocalSymbolIndex;
// This holds the .strtab section index.
unsigned StringTableIndex;
+ // This holds the .symtab section index.
+ unsigned SymbolTableIndex;
unsigned ShstrtabIndex;
public:
ELFObjectWriterImpl(ELFObjectWriter *_Writer, bool _Is64Bit,
- bool _HasRelAddend, Triple::OSType _OSType)
- : Writer(_Writer), OS(Writer->getStream()),
+ uint16_t _EMachine, bool _HasRelAddend,
+ Triple::OSType _OSType)
+ : NeedsGOT(false), NeedsSymtabShndx(false), Writer(_Writer),
+ OS(Writer->getStream()),
Is64Bit(_Is64Bit), HasRelocationAddend(_HasRelAddend),
- OSType(_OSType) {
+ OSType(_OSType), EMachine(_EMachine) {
}
void Write8(uint8_t Value) { Writer->Write8(Value); }
void WriteHeader(uint64_t SectionDataSize, unsigned NumberOfSections);
- void WriteSymbolEntry(MCDataFragment *F, uint64_t name, uint8_t info,
+ void WriteSymbolEntry(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
+ uint64_t name, uint8_t info,
uint64_t value, uint64_t size,
- uint8_t other, uint16_t shndx);
+ uint8_t other, uint32_t shndx,
+ bool Reserved);
- void WriteSymbol(MCDataFragment *F, ELFSymbolData &MSD,
+ void WriteSymbol(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
+ ELFSymbolData &MSD,
const MCAsmLayout &Layout);
- void WriteSymbolTable(MCDataFragment *F, const MCAssembler &Asm,
+ void WriteSymbolTable(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
+ const MCAssembler &Asm,
const MCAsmLayout &Layout,
unsigned NumRegularSections);
void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout);
- void ExecutePostLayoutBinding(MCAssembler &Asm) {
- // Compute symbol table information.
- ComputeSymbolTable(Asm);
- }
+ void ExecutePostLayoutBinding(MCAssembler &Asm);
void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
uint64_t Address, uint64_t Offset,
bool IsPCRel,
const MCFragment *DF) const;
- void WriteObject(const MCAssembler &Asm, const MCAsmLayout &Layout);
+ void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
};
}
Write16(ELF::ET_REL); // e_type
- // FIXME: Make this configurable
- Write16(Is64Bit ? ELF::EM_X86_64 : ELF::EM_386); // e_machine = target
+ Write16(EMachine); // e_machine = target
Write32(ELF::EV_CURRENT); // e_version
WriteWord(0); // e_entry, no entry point in .o file
Write16(Is64Bit ? sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr));
// e_shnum = # of section header ents
- Write16(NumberOfSections);
+ if (NumberOfSections >= ELF::SHN_LORESERVE)
+ Write16(0);
+ else
+ Write16(NumberOfSections);
// e_shstrndx = Section # of '.shstrtab'
- Write16(ShstrtabIndex);
+ if (NumberOfSections >= ELF::SHN_LORESERVE)
+ Write16(ELF::SHN_XINDEX);
+ else
+ Write16(ShstrtabIndex);
}
-void ELFObjectWriterImpl::WriteSymbolEntry(MCDataFragment *F, uint64_t name,
+void ELFObjectWriterImpl::WriteSymbolEntry(MCDataFragment *SymtabF,
+ MCDataFragment *ShndxF,
+ uint64_t name,
uint8_t info, uint64_t value,
uint64_t size, uint8_t other,
- uint16_t shndx) {
+ uint32_t shndx,
+ bool Reserved) {
+ if (ShndxF) {
+ char buf[4];
+ if (shndx >= ELF::SHN_LORESERVE && !Reserved)
+ String32(buf, shndx);
+ else
+ String32(buf, 0);
+ ShndxF->getContents() += StringRef(buf, 4);
+ }
+
if (Is64Bit) {
char buf[8];
String32(buf, name);
- F->getContents() += StringRef(buf, 4); // st_name
+ SymtabF->getContents() += StringRef(buf, 4); // st_name
String8(buf, info);
- F->getContents() += StringRef(buf, 1); // st_info
+ SymtabF->getContents() += StringRef(buf, 1); // st_info
String8(buf, other);
- F->getContents() += StringRef(buf, 1); // st_other
+ SymtabF->getContents() += StringRef(buf, 1); // st_other
+
+ if (shndx >= ELF::SHN_LORESERVE && !Reserved)
+ String16(buf, ELF::SHN_XINDEX);
+ else
+ String16(buf, shndx);
- String16(buf, shndx);
- F->getContents() += StringRef(buf, 2); // st_shndx
+ SymtabF->getContents() += StringRef(buf, 2); // st_shndx
String64(buf, value);
- F->getContents() += StringRef(buf, 8); // st_value
+ SymtabF->getContents() += StringRef(buf, 8); // st_value
String64(buf, size);
- F->getContents() += StringRef(buf, 8); // st_size
+ SymtabF->getContents() += StringRef(buf, 8); // st_size
} else {
char buf[4];
String32(buf, name);
- F->getContents() += StringRef(buf, 4); // st_name
+ SymtabF->getContents() += StringRef(buf, 4); // st_name
String32(buf, value);
- F->getContents() += StringRef(buf, 4); // st_value
+ SymtabF->getContents() += StringRef(buf, 4); // st_value
String32(buf, size);
- F->getContents() += StringRef(buf, 4); // st_size
+ SymtabF->getContents() += StringRef(buf, 4); // st_size
String8(buf, info);
- F->getContents() += StringRef(buf, 1); // st_info
+ SymtabF->getContents() += StringRef(buf, 1); // st_info
String8(buf, other);
- F->getContents() += StringRef(buf, 1); // st_other
+ SymtabF->getContents() += StringRef(buf, 1); // st_other
- String16(buf, shndx);
- F->getContents() += StringRef(buf, 2); // st_shndx
+ if (shndx >= ELF::SHN_LORESERVE && !Reserved)
+ String16(buf, ELF::SHN_XINDEX);
+ else
+ String16(buf, shndx);
+
+ SymtabF->getContents() += StringRef(buf, 2); // st_shndx
}
}
if (!Symbol.isInSection())
return 0;
- if (!Data.isCommon() && !(Data.getFlags() & ELF_STB_Weak))
- if (MCFragment *FF = Data.getFragment())
- return Layout.getSymbolAddress(&Data) -
- Layout.getSectionAddress(FF->getParent());
+ if (MCFragment *FF = Data.getFragment())
+ return Layout.getSymbolAddress(&Data) -
+ Layout.getSectionAddress(FF->getParent());
return 0;
}
-void ELFObjectWriterImpl::WriteSymbol(MCDataFragment *F, ELFSymbolData &MSD,
+static const MCSymbol &AliasedSymbol(const MCSymbol &Symbol) {
+ const MCSymbol *S = &Symbol;
+ while (S->isVariable()) {
+ const MCExpr *Value = S->getVariableValue();
+ if (Value->getKind() != MCExpr::SymbolRef)
+ return *S;
+ const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr*>(Value);
+ S = &Ref->getSymbol();
+ }
+ return *S;
+}
+
+void ELFObjectWriterImpl::ExecutePostLayoutBinding(MCAssembler &Asm) {
+ // The presence of symbol versions causes undefined symbols and
+ // versions declared with @@@ to be renamed.
+
+ for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
+ ie = Asm.symbol_end(); it != ie; ++it) {
+ const MCSymbol &Alias = it->getSymbol();
+ const MCSymbol &Symbol = AliasedSymbol(Alias);
+ MCSymbolData &SD = Asm.getSymbolData(Symbol);
+
+ // Undefined symbols are global, but this is the first place we
+ // are able to set it.
+ if (Symbol.isUndefined() && !Symbol.isVariable()) {
+ if (GetBinding(SD) == ELF::STB_LOCAL) {
+ SetBinding(SD, ELF::STB_GLOBAL);
+ SetBinding(*it, ELF::STB_GLOBAL);
+ }
+ }
+
+ // Not an alias.
+ if (&Symbol == &Alias)
+ continue;
+
+ StringRef AliasName = Alias.getName();
+ size_t Pos = AliasName.find('@');
+ if (Pos == StringRef::npos)
+ continue;
+
+ // Aliases defined with .symvar copy the binding from the symbol they alias.
+ // This is the first place we are able to copy this information.
+ it->setExternal(SD.isExternal());
+ SetBinding(*it, GetBinding(SD));
+
+ StringRef Rest = AliasName.substr(Pos);
+ if (!Symbol.isUndefined() && !Rest.startswith("@@@"))
+ continue;
+
+ // FIXME: produce a better error message.
+ if (Symbol.isUndefined() && Rest.startswith("@@") &&
+ !Rest.startswith("@@@"))
+ report_fatal_error("A @@ version cannot be undefined");
+
+ Renames.insert(std::make_pair(&Symbol, &Alias));
+ }
+}
+
+void ELFObjectWriterImpl::WriteSymbol(MCDataFragment *SymtabF,
+ MCDataFragment *ShndxF,
+ ELFSymbolData &MSD,
const MCAsmLayout &Layout) {
- MCSymbolData &Data = *MSD.SymbolData;
- uint8_t Info = (Data.getFlags() & 0xff);
- uint8_t Other = ((Data.getFlags() & 0xf00) >> ELF_STV_Shift);
+ MCSymbolData &OrigData = *MSD.SymbolData;
+ MCSymbolData &Data =
+ Layout.getAssembler().getSymbolData(AliasedSymbol(OrigData.getSymbol()));
+
+ bool IsReserved = Data.isCommon() || Data.getSymbol().isAbsolute() ||
+ Data.getSymbol().isVariable();
+
+ uint8_t Binding = GetBinding(OrigData);
+ uint8_t Visibility = GetVisibility(OrigData);
+ uint8_t Type = GetType(Data);
+
+ uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift);
+ uint8_t Other = Visibility;
+
uint64_t Value = SymbolValue(Data, Layout);
uint64_t Size = 0;
const MCExpr *ESize;
const MCBinaryExpr *BE = static_cast<const MCBinaryExpr *>(ESize);
if (BE->EvaluateAsRelocatable(Res, &Layout)) {
- MCSymbolData &A =
- Layout.getAssembler().getSymbolData(Res.getSymA()->getSymbol());
- MCSymbolData &B =
- Layout.getAssembler().getSymbolData(Res.getSymB()->getSymbol());
-
- Size = Layout.getSymbolAddress(&A) - Layout.getSymbolAddress(&B);
+ assert(!Res.getSymA() || !Res.getSymA()->getSymbol().isDefined());
+ assert(!Res.getSymB() || !Res.getSymB()->getSymbol().isDefined());
+ Size = Res.getConstant();
}
} else if (ESize->getKind() == MCExpr::Constant) {
Size = static_cast<const MCConstantExpr *>(ESize)->getValue();
}
// Write out the symbol table entry
- WriteSymbolEntry(F, MSD.StringIndex, Info, Value,
- Size, Other, MSD.SectionIndex);
+ WriteSymbolEntry(SymtabF, ShndxF, MSD.StringIndex, Info, Value,
+ Size, Other, MSD.SectionIndex, IsReserved);
}
-void ELFObjectWriterImpl::WriteSymbolTable(MCDataFragment *F,
+void ELFObjectWriterImpl::WriteSymbolTable(MCDataFragment *SymtabF,
+ MCDataFragment *ShndxF,
const MCAssembler &Asm,
const MCAsmLayout &Layout,
unsigned NumRegularSections) {
// FIXME: Make sure the start of the symbol table is aligned.
// The first entry is the undefined symbol entry.
- unsigned EntrySize = Is64Bit ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
- F->getContents().append(EntrySize, '\x00');
+ WriteSymbolEntry(SymtabF, ShndxF, 0, 0, 0, 0, 0, 0, false);
// Write the symbol table entries.
LastLocalSymbolIndex = LocalSymbolData.size() + 1;
for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) {
ELFSymbolData &MSD = LocalSymbolData[i];
- WriteSymbol(F, MSD, Layout);
+ WriteSymbol(SymtabF, ShndxF, MSD, Layout);
}
// Write out a symbol table entry for each regular section.
// the relocations messed up
if (Section.getType() == ELF::SHT_RELA || Section.getType() == ELF::SHT_REL)
continue;
- WriteSymbolEntry(F, 0, ELF::STT_SECTION, 0, 0, ELF::STV_DEFAULT, Index);
+ WriteSymbolEntry(SymtabF, ShndxF, 0, ELF::STT_SECTION, 0, 0,
+ ELF::STV_DEFAULT, Index, false);
LastLocalSymbolIndex++;
}
for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) {
ELFSymbolData &MSD = ExternalSymbolData[i];
MCSymbolData &Data = *MSD.SymbolData;
- assert((Data.getFlags() & ELF_STB_Global) &&
- "External symbol requires STB_GLOBAL flag");
- WriteSymbol(F, MSD, Layout);
+ assert(((Data.getFlags() & ELF_STB_Global) ||
+ (Data.getFlags() & ELF_STB_Weak)) &&
+ "External symbol requires STB_GLOBAL or STB_WEAK flag");
+ WriteSymbol(SymtabF, ShndxF, MSD, Layout);
if (GetBinding(Data) == ELF::STB_LOCAL)
LastLocalSymbolIndex++;
}
for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) {
ELFSymbolData &MSD = UndefinedSymbolData[i];
MCSymbolData &Data = *MSD.SymbolData;
- WriteSymbol(F, MSD, Layout);
+ WriteSymbol(SymtabF, ShndxF, MSD, Layout);
if (GetBinding(Data) == ELF::STB_LOCAL)
LastLocalSymbolIndex++;
}
}
static bool ShouldRelocOnSymbol(const MCSymbolData &SD,
- const MCValue &Target) {
+ const MCValue &Target,
+ const MCFragment &F) {
const MCSymbol &Symbol = SD.getSymbol();
if (Symbol.isUndefined())
return true;
const MCSectionELF &Section =
static_cast<const MCSectionELF&>(Symbol.getSection());
- if (Section.getFlags() & MCSectionELF::SHF_MERGE)
- return Target.getConstant() != 0;
-
if (SD.isExternal())
return true;
+ MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind();
+ const MCSectionELF &Sec2 =
+ static_cast<const MCSectionELF&>(F.getParent()->getSection());
+
+ if (Section.getKind().isBSS())
+ return false;
+
+ if (&Sec2 != &Section &&
+ (Kind == MCSymbolRefExpr::VK_PLT ||
+ Kind == MCSymbolRefExpr::VK_GOTPCREL ||
+ Kind == MCSymbolRefExpr::VK_GOTOFF))
+ return true;
+
+ if (Section.getFlags() & MCSectionELF::SHF_MERGE)
+ return Target.getConstant() != 0;
+
return false;
}
MCValue Target,
uint64_t &FixedValue) {
int64_t Addend = 0;
- unsigned Index = 0;
+ int Index = 0;
int64_t Value = Target.getConstant();
+ const MCSymbol *Symbol = 0;
+ const MCSymbol *Renamed = 0;
bool IsPCRel = isFixupKindX86PCRel(Fixup.getKind());
if (!Target.isAbsolute()) {
- const MCSymbol *Symbol = &Target.getSymA()->getSymbol();
+ Symbol = &AliasedSymbol(Target.getSymA()->getSymbol());
+ Renamed = Renames.lookup(Symbol);
+ if (!Renamed)
+ Renamed = &Target.getSymA()->getSymbol();
MCSymbolData &SD = Asm.getSymbolData(*Symbol);
MCFragment *F = SD.getFragment();
+ if (const MCSymbolRefExpr *RefB = Target.getSymB()) {
+ const MCSymbol &SymbolB = RefB->getSymbol();
+ MCSymbolData &SDB = Asm.getSymbolData(SymbolB);
+ IsPCRel = true;
+ MCSectionData *Sec = Fragment->getParent();
+
+ // Offset of the symbol in the section
+ int64_t a = Layout.getSymbolAddress(&SDB) - Layout.getSectionAddress(Sec);
+
+ // Ofeset of the relocation in the section
+ int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
+ Value += b - a;
+ }
+
// Check that this case has already been fully resolved before we get
// here.
if (Symbol->isDefined() && !SD.isExternal() &&
return;
}
- bool RelocOnSymbol = ShouldRelocOnSymbol(SD, Target);
+ bool RelocOnSymbol = ShouldRelocOnSymbol(SD, Target, *Fragment);
if (!RelocOnSymbol) {
- Index = F->getParent()->getOrdinal() + LocalSymbolData.size() + 1;
+ Index = F->getParent()->getOrdinal();
MCSectionData *FSD = F->getParent();
// Offset of the symbol in the section
Value += Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD);
- } else
- Index = getSymbolIndexInSymbolTable(Asm, Symbol);
+ } else {
+ UsedInReloc.insert(Renamed);
+ MCSymbolData &RenamedSD = Asm.getSymbolData(*Renamed);
+ if (RenamedSD.getFlags() & ELF_Other_Weakref) {
+ WeakrefUsedInReloc.insert(Symbol);
+ }
+ Index = -1;
+ }
Addend = Value;
// Compensate for the addend on i386.
if (Is64Bit)
FixedValue = Value;
// determine the type of the relocation
+
+ MCSymbolRefExpr::VariantKind Modifier = Target.getSymA()->getKind();
unsigned Type;
if (Is64Bit) {
if (IsPCRel) {
- Type = ELF::R_X86_64_PC32;
+ switch (Modifier) {
+ default:
+ llvm_unreachable("Unimplemented");
+ case MCSymbolRefExpr::VK_None:
+ Type = ELF::R_X86_64_PC32;
+ break;
+ case MCSymbolRefExpr::VK_PLT:
+ Type = ELF::R_X86_64_PLT32;
+ break;
+ case MCSymbolRefExpr::VK_GOTPCREL:
+ Type = ELF::R_X86_64_GOTPCREL;
+ break;
+ case MCSymbolRefExpr::VK_GOTTPOFF:
+ Type = ELF::R_X86_64_GOTTPOFF;
+ break;
+ case MCSymbolRefExpr::VK_TLSGD:
+ Type = ELF::R_X86_64_TLSGD;
+ break;
+ case MCSymbolRefExpr::VK_TLSLD:
+ Type = ELF::R_X86_64_TLSLD;
+ break;
+ }
} else {
switch ((unsigned)Fixup.getKind()) {
default: llvm_unreachable("invalid fixup kind!");
case X86::reloc_signed_4byte:
case X86::reloc_pcrel_4byte:
assert(isInt<32>(Target.getConstant()));
- Type = ELF::R_X86_64_32S;
+ switch (Modifier) {
+ default:
+ llvm_unreachable("Unimplemented");
+ case MCSymbolRefExpr::VK_None:
+ Type = ELF::R_X86_64_32S;
+ break;
+ case MCSymbolRefExpr::VK_GOT:
+ Type = ELF::R_X86_64_GOT32;
+ break;
+ case MCSymbolRefExpr::VK_GOTPCREL:
+ Type = ELF::R_X86_64_GOTPCREL;
+ break;
+ case MCSymbolRefExpr::VK_TPOFF:
+ Type = ELF::R_X86_64_TPOFF32;
+ break;
+ case MCSymbolRefExpr::VK_DTPOFF:
+ Type = ELF::R_X86_64_DTPOFF32;
+ break;
+ }
break;
case FK_Data_4:
Type = ELF::R_X86_64_32;
}
} else {
if (IsPCRel) {
- Type = ELF::R_386_PC32;
+ switch (Modifier) {
+ default:
+ llvm_unreachable("Unimplemented");
+ case MCSymbolRefExpr::VK_None:
+ Type = ELF::R_386_PC32;
+ break;
+ case MCSymbolRefExpr::VK_PLT:
+ Type = ELF::R_386_PLT32;
+ break;
+ }
} else {
switch ((unsigned)Fixup.getKind()) {
default: llvm_unreachable("invalid fixup kind!");
+ case X86::reloc_global_offset_table:
+ Type = ELF::R_386_GOTPC;
+ break;
+
// FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode
// instead?
case X86::reloc_signed_4byte:
case X86::reloc_pcrel_4byte:
- case FK_Data_4: Type = ELF::R_386_32; break;
+ case FK_Data_4:
+ switch (Modifier) {
+ default:
+ llvm_unreachable("Unimplemented");
+ case MCSymbolRefExpr::VK_None:
+ Type = ELF::R_386_32;
+ break;
+ case MCSymbolRefExpr::VK_GOT:
+ Type = ELF::R_386_GOT32;
+ break;
+ case MCSymbolRefExpr::VK_GOTOFF:
+ Type = ELF::R_386_GOTOFF;
+ break;
+ case MCSymbolRefExpr::VK_TLSGD:
+ Type = ELF::R_386_TLS_GD;
+ break;
+ case MCSymbolRefExpr::VK_TPOFF:
+ Type = ELF::R_386_TLS_LE_32;
+ break;
+ case MCSymbolRefExpr::VK_INDNTPOFF:
+ Type = ELF::R_386_TLS_IE;
+ break;
+ case MCSymbolRefExpr::VK_NTPOFF:
+ Type = ELF::R_386_TLS_LE;
+ break;
+ case MCSymbolRefExpr::VK_GOTNTPOFF:
+ Type = ELF::R_386_TLS_GOTIE;
+ break;
+ case MCSymbolRefExpr::VK_TLSLDM:
+ Type = ELF::R_386_TLS_LDM;
+ break;
+ case MCSymbolRefExpr::VK_DTPOFF:
+ Type = ELF::R_386_TLS_LDO_32;
+ break;
+ }
+ break;
case FK_Data_2: Type = ELF::R_386_16; break;
case X86::reloc_pcrel_1byte:
case FK_Data_1: Type = ELF::R_386_8; break;
}
}
+ if (RelocNeedsGOT(Modifier))
+ NeedsGOT = true;
+
ELFRelocationEntry ERE;
- if (Is64Bit) {
- struct ELF::Elf64_Rela ERE64;
- ERE64.setSymbolAndType(Index, Type);
- ERE.r_info = ERE64.r_info;
- } else {
- struct ELF::Elf32_Rela ERE32;
- ERE32.setSymbolAndType(Index, Type);
- ERE.r_info = ERE32.r_info;
- }
+ ERE.Index = Index;
+ ERE.Type = Type;
+ ERE.Symbol = Renamed;
ERE.r_offset = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
return SD.getIndex() + /* empty symbol */ 1;
// External or undefined symbol.
- return SD.getIndex() + Asm.size() + /* empty symbol */ 1;
+ return SD.getIndex() + NumRegularSections + /* empty symbol */ 1;
+}
+
+static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data,
+ bool Used, bool Renamed) {
+ if (Data.getFlags() & ELF_Other_Weakref)
+ return false;
+
+ if (Used)
+ return true;
+
+ if (Renamed)
+ return false;
+
+ const MCSymbol &Symbol = Data.getSymbol();
+
+ if (Symbol.getName() == "_GLOBAL_OFFSET_TABLE_")
+ return true;
+
+ const MCSymbol &A = AliasedSymbol(Symbol);
+ if (!A.isVariable() && A.isUndefined() && !Data.isCommon())
+ return false;
+
+ if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
+ return false;
+
+ if (Symbol.isTemporary())
+ return false;
+
+ return true;
+}
+
+static bool isLocal(const MCSymbolData &Data) {
+ if (Data.isExternal())
+ return false;
+
+ const MCSymbol &Symbol = Data.getSymbol();
+ if (Symbol.isUndefined() && !Symbol.isVariable())
+ return false;
+
+ return true;
}
void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) {
+ // FIXME: Is this the correct place to do this?
+ if (NeedsGOT) {
+ llvm::StringRef Name = "_GLOBAL_OFFSET_TABLE_";
+ MCSymbol *Sym = Asm.getContext().GetOrCreateSymbol(Name);
+ MCSymbolData &Data = Asm.getOrCreateSymbolData(*Sym);
+ Data.setExternal(true);
+ SetBinding(Data, ELF::STB_GLOBAL);
+ }
+
// Build section lookup table.
- DenseMap<const MCSection*, uint8_t> SectionIndexMap;
+ NumRegularSections = Asm.size();
+ DenseMap<const MCSection*, uint32_t> SectionIndexMap;
unsigned Index = 1;
for (MCAssembler::iterator it = Asm.begin(),
ie = Asm.end(); it != ie; ++it, ++Index)
StringMap<uint64_t> StringIndexMap;
StringTable += '\x00';
- // Add the data for local symbols.
+ // Add the data for the symbols.
for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
ie = Asm.symbol_end(); it != ie; ++it) {
const MCSymbol &Symbol = it->getSymbol();
- // Ignore non-linker visible symbols.
- if (!Asm.isSymbolLinkerVisible(Symbol))
- continue;
-
- if (it->isExternal() || Symbol.isUndefined())
+ bool Used = UsedInReloc.count(&Symbol);
+ bool WeakrefUsed = WeakrefUsedInReloc.count(&Symbol);
+ if (!isInSymtab(Asm, *it, Used || WeakrefUsed,
+ Renames.count(&Symbol)))
continue;
- uint64_t &Entry = StringIndexMap[Symbol.getName()];
- if (!Entry) {
- Entry = StringTable.size();
- StringTable += Symbol.getName();
- StringTable += '\x00';
- }
-
ELFSymbolData MSD;
MSD.SymbolData = it;
- MSD.StringIndex = Entry;
+ bool Local = isLocal(*it);
+ const MCSymbol &RefSymbol = AliasedSymbol(Symbol);
+
+ if (RefSymbol.isUndefined() && !Used && WeakrefUsed)
+ SetBinding(*it, ELF::STB_WEAK);
- if (Symbol.isAbsolute()) {
+ if (it->isCommon()) {
+ assert(!Local);
+ MSD.SectionIndex = ELF::SHN_COMMON;
+ } else if (Symbol.isAbsolute() || RefSymbol.isVariable()) {
MSD.SectionIndex = ELF::SHN_ABS;
- LocalSymbolData.push_back(MSD);
+ } else if (RefSymbol.isUndefined()) {
+ MSD.SectionIndex = ELF::SHN_UNDEF;
} else {
- MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection());
+ MSD.SectionIndex = SectionIndexMap.lookup(&RefSymbol.getSection());
+ if (MSD.SectionIndex >= ELF::SHN_LORESERVE)
+ NeedsSymtabShndx = true;
assert(MSD.SectionIndex && "Invalid section index!");
- LocalSymbolData.push_back(MSD);
}
- }
-
- // Now add non-local symbols.
- for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
- ie = Asm.symbol_end(); it != ie; ++it) {
- const MCSymbol &Symbol = it->getSymbol();
-
- // Ignore non-linker visible symbols.
- if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
- continue;
- if (!it->isExternal() && !Symbol.isUndefined())
- continue;
-
- if (Symbol.isVariable())
- continue;
+ // The @@@ in symbol version is replaced with @ in undefined symbols and
+ // @@ in defined ones.
+ StringRef Name = Symbol.getName();
+ size_t Pos = Name.find("@@@");
+ std::string FinalName;
+ if (Pos != StringRef::npos) {
+ StringRef Prefix = Name.substr(0, Pos);
+ unsigned n = MSD.SectionIndex == ELF::SHN_UNDEF ? 2 : 1;
+ StringRef Suffix = Name.substr(Pos + n);
+ FinalName = Prefix.str() + Suffix.str();
+ } else {
+ FinalName = Name.str();
+ }
- uint64_t &Entry = StringIndexMap[Symbol.getName()];
+ uint64_t &Entry = StringIndexMap[FinalName];
if (!Entry) {
Entry = StringTable.size();
- StringTable += Symbol.getName();
+ StringTable += FinalName;
StringTable += '\x00';
}
-
- ELFSymbolData MSD;
- MSD.SymbolData = it;
MSD.StringIndex = Entry;
-
- if (it->isCommon()) {
- MSD.SectionIndex = ELF::SHN_COMMON;
- ExternalSymbolData.push_back(MSD);
- } else if (Symbol.isUndefined()) {
- MSD.SectionIndex = ELF::SHN_UNDEF;
- // FIXME: Undefined symbols are global, but this is the first place we
- // are able to set it.
- if (GetBinding(*it) == ELF::STB_LOCAL)
- SetBinding(*it, ELF::STB_GLOBAL);
+ if (MSD.SectionIndex == ELF::SHN_UNDEF)
UndefinedSymbolData.push_back(MSD);
- } else if (Symbol.isAbsolute()) {
- MSD.SectionIndex = ELF::SHN_ABS;
- ExternalSymbolData.push_back(MSD);
- } else {
- MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection());
- assert(MSD.SectionIndex && "Invalid section index!");
+ else if (Local)
+ LocalSymbolData.push_back(MSD);
+ else
ExternalSymbolData.push_back(MSD);
- }
}
// Symbols are required to be in lexicographic order.
for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
ELFRelocationEntry entry = Relocs[e - i - 1];
+ if (entry.Index < 0)
+ entry.Index = getSymbolIndexInSymbolTable(Asm, entry.Symbol);
+ else
+ entry.Index += LocalSymbolData.size() + 1;
if (Is64Bit) {
char buf[8];
String64(buf, entry.r_offset);
F->getContents() += StringRef(buf, 8);
- String64(buf, entry.r_info);
+ struct ELF::Elf64_Rela ERE64;
+ ERE64.setSymbolAndType(entry.Index, entry.Type);
+ String64(buf, ERE64.r_info);
F->getContents() += StringRef(buf, 8);
if (HasRelocationAddend) {
String32(buf, entry.r_offset);
F->getContents() += StringRef(buf, 4);
- String32(buf, entry.r_info);
+ struct ELF::Elf32_Rela ERE32;
+ ERE32.setSymbolAndType(entry.Index, entry.Type);
+ String32(buf, ERE32.r_info);
F->getContents() += StringRef(buf, 4);
if (HasRelocationAddend) {
MCContext &Ctx = Asm.getContext();
MCDataFragment *F;
- const MCSection *SymtabSection;
unsigned EntrySize = Is64Bit ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
unsigned NumRegularSections = Asm.size();
// We construct .shstrtab, .symtab and .strtab in this order to match gnu as.
- const MCSection *ShstrtabSection;
- ShstrtabSection = Ctx.getELFSection(".shstrtab", ELF::SHT_STRTAB, 0,
- SectionKind::getReadOnly(), false);
+ const MCSection *ShstrtabSection =
+ Ctx.getELFSection(".shstrtab", ELF::SHT_STRTAB, 0,
+ SectionKind::getReadOnly(), false);
MCSectionData &ShstrtabSD = Asm.getOrCreateSectionData(*ShstrtabSection);
ShstrtabSD.setAlignment(1);
ShstrtabIndex = Asm.size();
- SymtabSection = Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
- SectionKind::getReadOnly(),
- false, EntrySize);
+ const MCSection *SymtabSection =
+ Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
+ SectionKind::getReadOnly(),
+ false, EntrySize);
MCSectionData &SymtabSD = Asm.getOrCreateSectionData(*SymtabSection);
SymtabSD.setAlignment(Is64Bit ? 8 : 4);
+ SymbolTableIndex = Asm.size();
+
+ MCSectionData *SymtabShndxSD = NULL;
+
+ if (NeedsSymtabShndx) {
+ const MCSection *SymtabShndxSection =
+ Ctx.getELFSection(".symtab_shndx", ELF::SHT_SYMTAB_SHNDX, 0,
+ SectionKind::getReadOnly(), false, 4);
+ SymtabShndxSD = &Asm.getOrCreateSectionData(*SymtabShndxSection);
+ SymtabShndxSD->setAlignment(4);
+ }
const MCSection *StrtabSection;
StrtabSection = Ctx.getELFSection(".strtab", ELF::SHT_STRTAB, 0,
// Symbol table
F = new MCDataFragment(&SymtabSD);
- WriteSymbolTable(F, Asm, Layout, NumRegularSections);
+ MCDataFragment *ShndxF = NULL;
+ if (NeedsSymtabShndx) {
+ ShndxF = new MCDataFragment(SymtabShndxSD);
+ Asm.AddSectionToTheEnd(*Writer, *SymtabShndxSD, Layout);
+ }
+ WriteSymbolTable(F, ShndxF, Asm, Layout, NumRegularSections);
Asm.AddSectionToTheEnd(*Writer, SymtabSD, Layout);
F = new MCDataFragment(&StrtabSD);
return !SectionB && BaseSection == SectionA;
}
-void ELFObjectWriterImpl::WriteObject(const MCAssembler &Asm,
+void ELFObjectWriterImpl::WriteObject(MCAssembler &Asm,
const MCAsmLayout &Layout) {
+ // Compute symbol table information.
+ ComputeSymbolTable(Asm);
+
CreateMetadataSections(const_cast<MCAssembler&>(Asm),
const_cast<MCAsmLayout&>(Layout));
// ... then all of the sections ...
DenseMap<const MCSection*, uint64_t> SectionOffsetMap;
- DenseMap<const MCSection*, uint8_t> SectionIndexMap;
+ DenseMap<const MCSection*, uint32_t> SectionIndexMap;
unsigned Index = 1;
for (MCAssembler::const_iterator it = Asm.begin(),
// Should we align the section header table?
//
// Null section first.
- WriteSecHdrEntry(0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
+ uint64_t FirstSectionSize =
+ NumSections >= ELF::SHN_LORESERVE ? NumSections : 0;
+ uint32_t FirstSectionLink =
+ ShstrtabIndex >= ELF::SHN_LORESERVE ? ShstrtabIndex : 0;
+ WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, FirstSectionLink, 0, 0, 0);
for (MCAssembler::const_iterator it = Asm.begin(),
ie = Asm.end(); it != ie; ++it) {
sh_info = LastLocalSymbolIndex;
break;
+ case ELF::SHT_SYMTAB_SHNDX:
+ sh_link = SymbolTableIndex;
+ break;
+
case ELF::SHT_PROGBITS:
case ELF::SHT_STRTAB:
case ELF::SHT_NOBITS:
case ELF::SHT_NULL:
+ case ELF::SHT_ARM_ATTRIBUTES:
// Nothing to do.
break;
- case ELF::SHT_HASH:
- case ELF::SHT_GROUP:
- case ELF::SHT_SYMTAB_SHNDX:
default:
assert(0 && "FIXME: sh_type value not supported!");
break;
ELFObjectWriter::ELFObjectWriter(raw_ostream &OS,
bool Is64Bit,
Triple::OSType OSType,
+ uint16_t EMachine,
bool IsLittleEndian,
bool HasRelocationAddend)
: MCObjectWriter(OS, IsLittleEndian)
{
- Impl = new ELFObjectWriterImpl(this, Is64Bit, HasRelocationAddend, OSType);
+ Impl = new ELFObjectWriterImpl(this, Is64Bit, EMachine,
+ HasRelocationAddend, OSType);
}
ELFObjectWriter::~ELFObjectWriter() {
IsPCRel, DF);
}
-void ELFObjectWriter::WriteObject(const MCAssembler &Asm,
+void ELFObjectWriter::WriteObject(MCAssembler &Asm,
const MCAsmLayout &Layout) {
((ELFObjectWriterImpl*) Impl)->WriteObject(Asm, Layout);
}
projects / oota-llvm.git / blobdiff