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-rw-r--r--lib/MC/ELFObjectWriter.cpp552
1 files changed, 202 insertions, 350 deletions
diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index 18746d1..0765937 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -21,12 +21,11 @@
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
-#include "llvm/MC/MCELF.h"
-#include "llvm/MC/MCELFSymbolFlags.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCFixupKindInfo.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSectionELF.h"
+#include "llvm/MC/MCSymbolELF.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/StringTableBuilder.h"
#include "llvm/Support/Compression.h"
@@ -71,23 +70,20 @@ public:
class ELFObjectWriter : public MCObjectWriter {
static bool isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind);
- static bool RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant);
static uint64_t SymbolValue(const MCSymbol &Sym, const MCAsmLayout &Layout);
- static bool isInSymtab(const MCAsmLayout &Layout, const MCSymbol &Symbol,
+ static bool isInSymtab(const MCAsmLayout &Layout, const MCSymbolELF &Symbol,
bool Used, bool Renamed);
- static bool isLocal(const MCSymbol &Symbol, bool isUsedInReloc);
/// Helper struct for containing some precomputed information on symbols.
struct ELFSymbolData {
- const MCSymbol *Symbol;
- uint64_t StringIndex;
+ const MCSymbolELF *Symbol;
uint32_t SectionIndex;
StringRef Name;
// Support lexicographic sorting.
bool operator<(const ELFSymbolData &RHS) const {
- unsigned LHSType = MCELF::GetType(Symbol->getData());
- unsigned RHSType = MCELF::GetType(RHS.Symbol->getData());
+ unsigned LHSType = Symbol->getType();
+ unsigned RHSType = RHS.Symbol->getType();
if (LHSType == ELF::STT_SECTION && RHSType != ELF::STT_SECTION)
return false;
if (LHSType != ELF::STT_SECTION && RHSType == ELF::STT_SECTION)
@@ -101,9 +97,7 @@ class ELFObjectWriter : public MCObjectWriter {
/// The target specific ELF writer instance.
std::unique_ptr<MCELFObjectTargetWriter> TargetObjectWriter;
- SmallPtrSet<const MCSymbol *, 16> UsedInReloc;
- SmallPtrSet<const MCSymbol *, 16> WeakrefUsedInReloc;
- DenseMap<const MCSymbol *, const MCSymbol *> Renames;
+ DenseMap<const MCSymbolELF *, const MCSymbolELF *> Renames;
llvm::DenseMap<const MCSectionELF *, std::vector<ELFRelocationEntry>>
Relocations;
@@ -113,15 +107,9 @@ class ELFObjectWriter : public MCObjectWriter {
/// @{
StringTableBuilder StrTabBuilder;
- std::vector<uint64_t> FileSymbolData;
- std::vector<ELFSymbolData> LocalSymbolData;
- std::vector<ELFSymbolData> ExternalSymbolData;
- std::vector<ELFSymbolData> UndefinedSymbolData;
/// @}
- bool NeedsGOT;
-
// This holds the symbol table index of the last local symbol.
unsigned LastLocalSymbolIndex;
// This holds the .strtab section index.
@@ -145,23 +133,17 @@ class ELFObjectWriter : public MCObjectWriter {
return TargetObjectWriter->GetRelocType(Target, Fixup, IsPCRel);
}
+ void align(unsigned Alignment);
+
public:
ELFObjectWriter(MCELFObjectTargetWriter *MOTW, raw_pwrite_stream &OS,
bool IsLittleEndian)
- : MCObjectWriter(OS, IsLittleEndian), TargetObjectWriter(MOTW),
- NeedsGOT(false) {}
+ : MCObjectWriter(OS, IsLittleEndian), TargetObjectWriter(MOTW) {}
void reset() override {
- UsedInReloc.clear();
- WeakrefUsedInReloc.clear();
Renames.clear();
Relocations.clear();
StrTabBuilder.clear();
- FileSymbolData.clear();
- LocalSymbolData.clear();
- ExternalSymbolData.clear();
- UndefinedSymbolData.clear();
- NeedsGOT = false;
SectionTable.clear();
MCObjectWriter::reset();
}
@@ -170,9 +152,9 @@ class ELFObjectWriter : public MCObjectWriter {
void WriteWord(uint64_t W) {
if (is64Bit())
- Write64(W);
+ write64(W);
else
- Write32(W);
+ write32(W);
}
template <typename T> void write(T Val) {
@@ -184,29 +166,23 @@ class ELFObjectWriter : public MCObjectWriter {
void writeHeader(const MCAssembler &Asm);
- void WriteSymbol(SymbolTableWriter &Writer, ELFSymbolData &MSD,
- const MCAsmLayout &Layout);
+ void writeSymbol(SymbolTableWriter &Writer, uint32_t StringIndex,
+ ELFSymbolData &MSD, const MCAsmLayout &Layout);
// Start and end offset of each section
typedef std::map<const MCSectionELF *, std::pair<uint64_t, uint64_t>>
SectionOffsetsTy;
- void writeSymbolTable(MCContext &Ctx, const MCAsmLayout &Layout,
- SectionOffsetsTy &SectionOffsets);
-
bool shouldRelocateWithSymbol(const MCAssembler &Asm,
const MCSymbolRefExpr *RefA,
const MCSymbol *Sym, uint64_t C,
unsigned Type) const;
- void RecordRelocation(MCAssembler &Asm, const MCAsmLayout &Layout,
+ void recordRelocation(MCAssembler &Asm, const MCAsmLayout &Layout,
const MCFragment *Fragment, const MCFixup &Fixup,
MCValue Target, bool &IsPCRel,
uint64_t &FixedValue) override;
- uint64_t getSymbolIndexInSymbolTable(const MCAssembler &Asm,
- const MCSymbol *S);
-
// Map from a signature symbol to the group section index
typedef DenseMap<const MCSymbol *, unsigned> RevGroupMapTy;
@@ -217,17 +193,18 @@ class ELFObjectWriter : public MCObjectWriter {
/// \param RevGroupMap - Maps a signature symbol to the group section.
void computeSymbolTable(MCAssembler &Asm, const MCAsmLayout &Layout,
const SectionIndexMapTy &SectionIndexMap,
- const RevGroupMapTy &RevGroupMap);
+ const RevGroupMapTy &RevGroupMap,
+ SectionOffsetsTy &SectionOffsets);
MCSectionELF *createRelocationSection(MCContext &Ctx,
const MCSectionELF &Sec);
const MCSectionELF *createStringTable(MCContext &Ctx);
- void ExecutePostLayoutBinding(MCAssembler &Asm,
+ void executePostLayoutBinding(MCAssembler &Asm,
const MCAsmLayout &Layout) override;
- void writeSectionHeader(const MCAssembler &Asm, const MCAsmLayout &Layout,
+ void writeSectionHeader(const MCAsmLayout &Layout,
const SectionIndexMapTy &SectionIndexMap,
const SectionOffsetsTy &SectionOffsets);
@@ -241,7 +218,7 @@ class ELFObjectWriter : public MCObjectWriter {
void writeRelocations(const MCAssembler &Asm, const MCSectionELF &Sec);
- bool IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
+ bool isSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
const MCSymbol &SymA,
const MCFragment &FB,
bool InSet,
@@ -249,13 +226,18 @@ class ELFObjectWriter : public MCObjectWriter {
bool isWeak(const MCSymbol &Sym) const override;
- void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout) override;
+ void writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) override;
void writeSection(const SectionIndexMapTy &SectionIndexMap,
uint32_t GroupSymbolIndex, uint64_t Offset, uint64_t Size,
const MCSectionELF &Section);
};
}
+void ELFObjectWriter::align(unsigned Alignment) {
+ uint64_t Padding = OffsetToAlignment(OS.tell(), Alignment);
+ WriteZeros(Padding);
+}
+
unsigned ELFObjectWriter::addToSectionTable(const MCSectionELF *Sec) {
SectionTable.push_back(Sec);
StrTabBuilder.add(Sec->getSectionName());
@@ -319,27 +301,6 @@ bool ELFObjectWriter::isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind) {
return FKI.Flags & MCFixupKindInfo::FKF_IsPCRel;
}
-bool ELFObjectWriter::RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant) {
- switch (Variant) {
- default:
- return false;
- case MCSymbolRefExpr::VK_GOT:
- case MCSymbolRefExpr::VK_PLT:
- case MCSymbolRefExpr::VK_GOTPCREL:
- case MCSymbolRefExpr::VK_GOTOFF:
- 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;
- }
-}
-
ELFObjectWriter::~ELFObjectWriter()
{}
@@ -353,54 +314,53 @@ void ELFObjectWriter::writeHeader(const MCAssembler &Asm) {
// emitWord method behaves differently for ELF32 and ELF64, writing
// 4 bytes in the former and 8 in the latter.
- WriteBytes(ELF::ElfMagic); // e_ident[EI_MAG0] to e_ident[EI_MAG3]
+ writeBytes(ELF::ElfMagic); // e_ident[EI_MAG0] to e_ident[EI_MAG3]
- Write8(is64Bit() ? ELF::ELFCLASS64 : ELF::ELFCLASS32); // e_ident[EI_CLASS]
+ write8(is64Bit() ? ELF::ELFCLASS64 : ELF::ELFCLASS32); // e_ident[EI_CLASS]
// e_ident[EI_DATA]
- Write8(isLittleEndian() ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
+ write8(isLittleEndian() ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
- Write8(ELF::EV_CURRENT); // e_ident[EI_VERSION]
+ write8(ELF::EV_CURRENT); // e_ident[EI_VERSION]
// e_ident[EI_OSABI]
- Write8(TargetObjectWriter->getOSABI());
- Write8(0); // e_ident[EI_ABIVERSION]
+ write8(TargetObjectWriter->getOSABI());
+ write8(0); // e_ident[EI_ABIVERSION]
WriteZeros(ELF::EI_NIDENT - ELF::EI_PAD);
- Write16(ELF::ET_REL); // e_type
+ write16(ELF::ET_REL); // e_type
- Write16(TargetObjectWriter->getEMachine()); // e_machine = target
+ write16(TargetObjectWriter->getEMachine()); // e_machine = target
- Write32(ELF::EV_CURRENT); // e_version
+ write32(ELF::EV_CURRENT); // e_version
WriteWord(0); // e_entry, no entry point in .o file
WriteWord(0); // e_phoff, no program header for .o
WriteWord(0); // e_shoff = sec hdr table off in bytes
// e_flags = whatever the target wants
- Write32(Asm.getELFHeaderEFlags());
+ write32(Asm.getELFHeaderEFlags());
// e_ehsize = ELF header size
- Write16(is64Bit() ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr));
+ write16(is64Bit() ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr));
- Write16(0); // e_phentsize = prog header entry size
- Write16(0); // e_phnum = # prog header entries = 0
+ write16(0); // e_phentsize = prog header entry size
+ write16(0); // e_phnum = # prog header entries = 0
// e_shentsize = Section header entry size
- Write16(is64Bit() ? sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr));
+ write16(is64Bit() ? sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr));
// e_shnum = # of section header ents
- Write16(0);
+ write16(0);
// e_shstrndx = Section # of '.shstrtab'
assert(StringTableIndex < ELF::SHN_LORESERVE);
- Write16(StringTableIndex);
+ write16(StringTableIndex);
}
uint64_t ELFObjectWriter::SymbolValue(const MCSymbol &Sym,
const MCAsmLayout &Layout) {
- MCSymbolData &Data = Sym.getData();
- if (Data.isCommon() && Data.isExternal())
- return Data.getCommonAlignment();
+ if (Sym.isCommon() && Sym.isExternal())
+ return Sym.getCommonAlignment();
uint64_t Res;
if (!Layout.getSymbolOffset(Sym, Res))
@@ -412,22 +372,20 @@ uint64_t ELFObjectWriter::SymbolValue(const MCSymbol &Sym,
return Res;
}
-void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
+void ELFObjectWriter::executePostLayoutBinding(MCAssembler &Asm,
const MCAsmLayout &Layout) {
// The presence of symbol versions causes undefined symbols and
// versions declared with @@@ to be renamed.
- for (const MCSymbol &Alias : Asm.symbols()) {
- MCSymbolData &OriginalData = Alias.getData();
-
+ for (const MCSymbol &A : Asm.symbols()) {
+ const auto &Alias = cast<MCSymbolELF>(A);
// Not an alias.
if (!Alias.isVariable())
continue;
auto *Ref = dyn_cast<MCSymbolRefExpr>(Alias.getVariableValue());
if (!Ref)
continue;
- const MCSymbol &Symbol = Ref->getSymbol();
- MCSymbolData &SD = Asm.getSymbolData(Symbol);
+ const auto &Symbol = cast<MCSymbolELF>(Ref->getSymbol());
StringRef AliasName = Alias.getName();
size_t Pos = AliasName.find('@');
@@ -436,8 +394,8 @@ void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
// Aliases defined with .symvar copy the binding from the symbol they alias.
// This is the first place we are able to copy this information.
- OriginalData.setExternal(SD.isExternal());
- MCELF::SetBinding(OriginalData, MCELF::GetBinding(SD));
+ Alias.setExternal(Symbol.isExternal());
+ Alias.setBinding(Symbol.getBinding());
StringRef Rest = AliasName.substr(Pos);
if (!Symbol.isUndefined() && !Rest.startswith("@@@"))
@@ -487,40 +445,39 @@ static uint8_t mergeTypeForSet(uint8_t origType, uint8_t newType) {
return Type;
}
-void ELFObjectWriter::WriteSymbol(SymbolTableWriter &Writer, ELFSymbolData &MSD,
+void ELFObjectWriter::writeSymbol(SymbolTableWriter &Writer,
+ uint32_t StringIndex, ELFSymbolData &MSD,
const MCAsmLayout &Layout) {
- MCSymbolData &OrigData = MSD.Symbol->getData();
- assert((!OrigData.getFragment() ||
- (OrigData.getFragment()->getParent() == &MSD.Symbol->getSection())) &&
+ const auto &Symbol = cast<MCSymbolELF>(*MSD.Symbol);
+ assert((!Symbol.getFragment() ||
+ (Symbol.getFragment()->getParent() == &Symbol.getSection())) &&
"The symbol's section doesn't match the fragment's symbol");
- const MCSymbol *Base = Layout.getBaseSymbol(*MSD.Symbol);
+ const MCSymbolELF *Base =
+ cast_or_null<MCSymbolELF>(Layout.getBaseSymbol(Symbol));
// This has to be in sync with when computeSymbolTable uses SHN_ABS or
// SHN_COMMON.
- bool IsReserved = !Base || OrigData.isCommon();
+ bool IsReserved = !Base || Symbol.isCommon();
// Binding and Type share the same byte as upper and lower nibbles
- uint8_t Binding = MCELF::GetBinding(OrigData);
- uint8_t Type = MCELF::GetType(OrigData);
- MCSymbolData *BaseSD = nullptr;
+ uint8_t Binding = Symbol.getBinding();
+ uint8_t Type = Symbol.getType();
if (Base) {
- BaseSD = &Layout.getAssembler().getSymbolData(*Base);
- Type = mergeTypeForSet(Type, MCELF::GetType(*BaseSD));
+ Type = mergeTypeForSet(Type, Base->getType());
}
- uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift);
+ uint8_t Info = (Binding << 4) | Type;
// 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;
+ uint8_t Visibility = Symbol.getVisibility();
+ uint8_t Other = Symbol.getOther() | Visibility;
uint64_t Value = SymbolValue(*MSD.Symbol, Layout);
uint64_t Size = 0;
- const MCExpr *ESize = OrigData.getSize();
+ const MCExpr *ESize = MSD.Symbol->getSize();
if (!ESize && Base)
- ESize = BaseSD->getSize();
+ ESize = Base->getSize();
if (ESize) {
int64_t Res;
@@ -530,78 +487,8 @@ void ELFObjectWriter::WriteSymbol(SymbolTableWriter &Writer, ELFSymbolData &MSD,
}
// Write out the symbol table entry
- Writer.writeSymbol(MSD.StringIndex, Info, Value, Size, Other,
- MSD.SectionIndex, IsReserved);
-}
-
-void ELFObjectWriter::writeSymbolTable(MCContext &Ctx,
- const MCAsmLayout &Layout,
- SectionOffsetsTy &SectionOffsets) {
- const MCSectionELF *SymtabSection = SectionTable[SymbolTableIndex - 1];
-
- // The string table must be emitted first because we need the index
- // into the string table for all the symbol names.
-
- SymbolTableWriter Writer(*this, is64Bit());
-
- uint64_t Padding =
- OffsetToAlignment(OS.tell(), SymtabSection->getAlignment());
- WriteZeros(Padding);
-
- uint64_t SecStart = OS.tell();
-
- // The first entry is the undefined symbol entry.
- Writer.writeSymbol(0, 0, 0, 0, 0, 0, false);
-
- for (unsigned i = 0, e = FileSymbolData.size(); i != e; ++i) {
- Writer.writeSymbol(FileSymbolData[i], ELF::STT_FILE | ELF::STB_LOCAL, 0, 0,
- ELF::STV_DEFAULT, ELF::SHN_ABS, true);
- }
-
- // Write the symbol table entries.
- LastLocalSymbolIndex = FileSymbolData.size() + LocalSymbolData.size() + 1;
-
- for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) {
- ELFSymbolData &MSD = LocalSymbolData[i];
- WriteSymbol(Writer, MSD, Layout);
- }
-
- for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) {
- ELFSymbolData &MSD = ExternalSymbolData[i];
- MCSymbolData &Data = MSD.Symbol->getData();
- assert(((Data.getFlags() & ELF_STB_Global) ||
- (Data.getFlags() & ELF_STB_Weak)) &&
- "External symbol requires STB_GLOBAL or STB_WEAK flag");
- WriteSymbol(Writer, MSD, Layout);
- if (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
- LastLocalSymbolIndex++;
- }
-
- for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) {
- ELFSymbolData &MSD = UndefinedSymbolData[i];
- MCSymbolData &Data = MSD.Symbol->getData();
- WriteSymbol(Writer, MSD, Layout);
- if (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
- LastLocalSymbolIndex++;
- }
-
- uint64_t SecEnd = OS.tell();
- SectionOffsets[SymtabSection] = std::make_pair(SecStart, SecEnd);
-
- ArrayRef<uint32_t> ShndxIndexes = Writer.getShndxIndexes();
- if (ShndxIndexes.empty()) {
- assert(SymtabShndxSectionIndex == 0);
- return;
- }
- assert(SymtabShndxSectionIndex != 0);
-
- SecStart = OS.tell();
- const MCSectionELF *SymtabShndxSection =
- SectionTable[SymtabShndxSectionIndex - 1];
- for (uint32_t Index : ShndxIndexes)
- write(Index);
- SecEnd = OS.tell();
- SectionOffsets[SymtabShndxSection] = std::make_pair(SecStart, SecEnd);
+ Writer.writeSymbol(StringIndex, Info, Value, Size, Other, MSD.SectionIndex,
+ IsReserved);
}
// It is always valid to create a relocation with a symbol. It is preferable
@@ -609,10 +496,9 @@ void ELFObjectWriter::writeSymbolTable(MCContext &Ctx,
// allows us to omit some local symbols from the symbol table.
bool ELFObjectWriter::shouldRelocateWithSymbol(const MCAssembler &Asm,
const MCSymbolRefExpr *RefA,
- const MCSymbol *Sym, uint64_t C,
+ const MCSymbol *S, uint64_t C,
unsigned Type) const {
- MCSymbolData *SD = Sym ? &Sym->getData() : nullptr;
-
+ const auto *Sym = cast_or_null<MCSymbolELF>(S);
// A PCRel relocation to an absolute value has no symbol (or section). We
// represent that with a relocation to a null section.
if (!RefA)
@@ -651,7 +537,7 @@ bool ELFObjectWriter::shouldRelocateWithSymbol(const MCAssembler &Asm,
if (Sym->isUndefined())
return true;
- unsigned Binding = MCELF::GetBinding(*SD);
+ unsigned Binding = Sym->getBinding();
switch(Binding) {
default:
llvm_unreachable("Invalid Binding");
@@ -701,38 +587,19 @@ bool ELFObjectWriter::shouldRelocateWithSymbol(const MCAssembler &Asm,
if (Asm.isThumbFunc(Sym))
return true;
- if (TargetObjectWriter->needsRelocateWithSymbol(*SD, Type))
+ if (TargetObjectWriter->needsRelocateWithSymbol(*Sym, Type))
return true;
return false;
}
-static const MCSymbol *getWeakRef(const MCSymbolRefExpr &Ref) {
- const MCSymbol &Sym = Ref.getSymbol();
-
- if (Ref.getKind() == MCSymbolRefExpr::VK_WEAKREF)
- return &Sym;
-
- if (!Sym.isVariable())
- return nullptr;
-
- const MCExpr *Expr = Sym.getVariableValue();
- const auto *Inner = dyn_cast<MCSymbolRefExpr>(Expr);
- if (!Inner)
- return nullptr;
-
- if (Inner->getKind() == MCSymbolRefExpr::VK_WEAKREF)
- return &Inner->getSymbol();
- return nullptr;
-}
-
// True if the assembler knows nothing about the final value of the symbol.
// This doesn't cover the comdat issues, since in those cases the assembler
// can at least know that all symbols in the section will move together.
-static bool isWeak(const MCSymbolData &D) {
- if (MCELF::GetType(D) == ELF::STT_GNU_IFUNC)
+static bool isWeak(const MCSymbolELF &Sym) {
+ if (Sym.getType() == ELF::STT_GNU_IFUNC)
return true;
- switch (MCELF::GetBinding(D)) {
+ switch (Sym.getBinding()) {
default:
llvm_unreachable("Unknown binding");
case ELF::STB_LOCAL:
@@ -745,7 +612,7 @@ static bool isWeak(const MCSymbolData &D) {
}
}
-void ELFObjectWriter::RecordRelocation(MCAssembler &Asm,
+void ELFObjectWriter::recordRelocation(MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFragment *Fragment,
const MCFixup &Fixup, MCValue Target,
@@ -770,7 +637,7 @@ void ELFObjectWriter::RecordRelocation(MCAssembler &Asm,
Fixup.getLoc(),
"No relocation available to represent this relative expression");
- const MCSymbol &SymB = RefB->getSymbol();
+ const auto &SymB = cast<MCSymbolELF>(RefB->getSymbol());
if (SymB.isUndefined())
Asm.getContext().reportFatalError(
@@ -784,7 +651,7 @@ void ELFObjectWriter::RecordRelocation(MCAssembler &Asm,
Asm.getContext().reportFatalError(
Fixup.getLoc(), "Cannot represent a difference across sections");
- if (::isWeak(SymB.getData()))
+ if (::isWeak(SymB))
Asm.getContext().reportFatalError(
Fixup.getLoc(), "Cannot represent a subtraction with a weak symbol");
@@ -796,7 +663,18 @@ void ELFObjectWriter::RecordRelocation(MCAssembler &Asm,
// We either rejected the fixup or folded B into C at this point.
const MCSymbolRefExpr *RefA = Target.getSymA();
- const MCSymbol *SymA = RefA ? &RefA->getSymbol() : nullptr;
+ const auto *SymA = RefA ? cast<MCSymbolELF>(&RefA->getSymbol()) : nullptr;
+
+ bool ViaWeakRef = false;
+ if (SymA && SymA->isVariable()) {
+ const MCExpr *Expr = SymA->getVariableValue();
+ if (const auto *Inner = dyn_cast<MCSymbolRefExpr>(Expr)) {
+ if (Inner->getKind() == MCSymbolRefExpr::VK_WEAKREF) {
+ SymA = cast<MCSymbolELF>(&Inner->getSymbol());
+ ViaWeakRef = true;
+ }
+ }
+ }
unsigned Type = GetRelocType(Target, Fixup, IsPCRel);
bool RelocateWithSymbol = shouldRelocateWithSymbol(Asm, RefA, SymA, C, Type);
@@ -811,50 +689,36 @@ void ELFObjectWriter::RecordRelocation(MCAssembler &Asm,
FixedValue = C;
- // FIXME: What is this!?!?
- MCSymbolRefExpr::VariantKind Modifier =
- RefA ? RefA->getKind() : MCSymbolRefExpr::VK_None;
- if (RelocNeedsGOT(Modifier))
- NeedsGOT = true;
-
if (!RelocateWithSymbol) {
const MCSection *SecA =
(SymA && !SymA->isUndefined()) ? &SymA->getSection() : nullptr;
auto *ELFSec = cast_or_null<MCSectionELF>(SecA);
- MCSymbol *SectionSymbol =
- ELFSec ? Asm.getContext().getOrCreateSectionSymbol(*ELFSec)
- : nullptr;
+ const auto *SectionSymbol =
+ ELFSec ? cast<MCSymbolELF>(ELFSec->getBeginSymbol()) : nullptr;
+ if (SectionSymbol)
+ SectionSymbol->setUsedInReloc();
ELFRelocationEntry Rec(FixupOffset, SectionSymbol, Type, Addend);
Relocations[&FixupSection].push_back(Rec);
return;
}
if (SymA) {
- if (const MCSymbol *R = Renames.lookup(SymA))
+ if (const MCSymbolELF *R = Renames.lookup(SymA))
SymA = R;
- if (const MCSymbol *WeakRef = getWeakRef(*RefA))
- WeakrefUsedInReloc.insert(WeakRef);
+ if (ViaWeakRef)
+ SymA->setIsWeakrefUsedInReloc();
else
- UsedInReloc.insert(SymA);
+ SymA->setUsedInReloc();
}
ELFRelocationEntry Rec(FixupOffset, SymA, Type, Addend);
Relocations[&FixupSection].push_back(Rec);
return;
}
-
-uint64_t
-ELFObjectWriter::getSymbolIndexInSymbolTable(const MCAssembler &Asm,
- const MCSymbol *S) {
- assert(S->hasData());
- return S->getIndex();
-}
-
bool ELFObjectWriter::isInSymtab(const MCAsmLayout &Layout,
- const MCSymbol &Symbol, bool Used,
+ const MCSymbolELF &Symbol, bool Used,
bool Renamed) {
- const MCSymbolData &Data = Symbol.getData();
if (Symbol.isVariable()) {
const MCExpr *Expr = Symbol.getVariableValue();
if (const MCSymbolRefExpr *Ref = dyn_cast<MCSymbolRefExpr>(Expr)) {
@@ -869,34 +733,19 @@ bool ELFObjectWriter::isInSymtab(const MCAsmLayout &Layout,
if (Renamed)
return false;
- if (Symbol.getName() == "_GLOBAL_OFFSET_TABLE_")
- return true;
-
- if (Symbol.isVariable()) {
- const MCSymbol *Base = Layout.getBaseSymbol(Symbol);
- if (Base && Base->isUndefined())
- return false;
+ if (Symbol.isVariable() && Symbol.isUndefined()) {
+ // FIXME: this is here just to diagnose the case of a var = commmon_sym.
+ Layout.getBaseSymbol(Symbol);
+ return false;
}
- bool IsGlobal = MCELF::GetBinding(Data) == ELF::STB_GLOBAL;
- if (!Symbol.isVariable() && Symbol.isUndefined() && !IsGlobal)
+ if (Symbol.isUndefined() && !Symbol.isBindingSet())
return false;
if (Symbol.isTemporary())
return false;
- return true;
-}
-
-bool ELFObjectWriter::isLocal(const MCSymbol &Symbol, bool isUsedInReloc) {
- const MCSymbolData &Data = Symbol.getData();
- if (Data.isExternal())
- return false;
-
- if (Symbol.isDefined())
- return true;
-
- if (isUsedInReloc)
+ if (Symbol.getType() == ELF::STT_SECTION)
return false;
return true;
@@ -904,9 +753,11 @@ bool ELFObjectWriter::isLocal(const MCSymbol &Symbol, bool isUsedInReloc) {
void ELFObjectWriter::computeSymbolTable(
MCAssembler &Asm, const MCAsmLayout &Layout,
- const SectionIndexMapTy &SectionIndexMap,
- const RevGroupMapTy &RevGroupMap) {
+ const SectionIndexMapTy &SectionIndexMap, const RevGroupMapTy &RevGroupMap,
+ SectionOffsetsTy &SectionOffsets) {
MCContext &Ctx = Asm.getContext();
+ SymbolTableWriter Writer(*this, is64Bit());
+
// Symbol table
unsigned EntrySize = is64Bit() ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
MCSectionELF *SymtabSection =
@@ -914,49 +765,37 @@ void ELFObjectWriter::computeSymbolTable(
SymtabSection->setAlignment(is64Bit() ? 8 : 4);
SymbolTableIndex = addToSectionTable(SymtabSection);
- // FIXME: Is this the correct place to do this?
- // FIXME: Why is an undefined reference to _GLOBAL_OFFSET_TABLE_ needed?
- if (NeedsGOT) {
- StringRef Name = "_GLOBAL_OFFSET_TABLE_";
- MCSymbol *Sym = Asm.getContext().getOrCreateSymbol(Name);
- MCSymbolData &Data = Asm.getOrCreateSymbolData(*Sym);
- Data.setExternal(true);
- MCELF::SetBinding(Data, ELF::STB_GLOBAL);
- }
+ align(SymtabSection->getAlignment());
+ uint64_t SecStart = OS.tell();
+
+ // The first entry is the undefined symbol entry.
+ Writer.writeSymbol(0, 0, 0, 0, 0, 0, false);
+
+ std::vector<ELFSymbolData> LocalSymbolData;
+ std::vector<ELFSymbolData> ExternalSymbolData;
// Add the data for the symbols.
bool HasLargeSectionIndex = false;
- for (const MCSymbol &Symbol : Asm.symbols()) {
- MCSymbolData &SD = Symbol.getData();
-
- bool Used = UsedInReloc.count(&Symbol);
- bool WeakrefUsed = WeakrefUsedInReloc.count(&Symbol);
- bool isSignature = RevGroupMap.count(&Symbol);
+ for (const MCSymbol &S : Asm.symbols()) {
+ const auto &Symbol = cast<MCSymbolELF>(S);
+ bool Used = Symbol.isUsedInReloc();
+ bool WeakrefUsed = Symbol.isWeakrefUsedInReloc();
+ bool isSignature = Symbol.isSignature();
if (!isInSymtab(Layout, Symbol, Used || WeakrefUsed || isSignature,
Renames.count(&Symbol)))
continue;
ELFSymbolData MSD;
- MSD.Symbol = &Symbol;
- const MCSymbol *BaseSymbol = Layout.getBaseSymbol(Symbol);
-
- // Undefined symbols are global, but this is the first place we
- // are able to set it.
- bool Local = isLocal(Symbol, Used);
- if (!Local && MCELF::GetBinding(SD) == ELF::STB_LOCAL) {
- assert(BaseSymbol);
- MCSymbolData &BaseData = Asm.getSymbolData(*BaseSymbol);
- MCELF::SetBinding(SD, ELF::STB_GLOBAL);
- MCELF::SetBinding(BaseData, ELF::STB_GLOBAL);
- }
+ MSD.Symbol = cast<MCSymbolELF>(&Symbol);
- if (!BaseSymbol) {
+ bool Local = Symbol.getBinding() == ELF::STB_LOCAL;
+ if (Symbol.isAbsolute()) {
MSD.SectionIndex = ELF::SHN_ABS;
- } else if (SD.isCommon()) {
+ } else if (Symbol.isCommon()) {
assert(!Local);
MSD.SectionIndex = ELF::SHN_COMMON;
- } else if (BaseSymbol->isUndefined()) {
+ } else if (Symbol.isUndefined()) {
if (isSignature && !Used) {
MSD.SectionIndex = RevGroupMap.lookup(&Symbol);
if (MSD.SectionIndex >= ELF::SHN_LORESERVE)
@@ -964,11 +803,9 @@ void ELFObjectWriter::computeSymbolTable(
} else {
MSD.SectionIndex = ELF::SHN_UNDEF;
}
- if (!Used && WeakrefUsed)
- MCELF::SetBinding(SD, ELF::STB_WEAK);
} else {
const MCSectionELF &Section =
- static_cast<const MCSectionELF&>(BaseSymbol->getSection());
+ static_cast<const MCSectionELF &>(Symbol.getSection());
MSD.SectionIndex = SectionIndexMap.lookup(&Section);
assert(MSD.SectionIndex && "Invalid section index!");
if (MSD.SectionIndex >= ELF::SHN_LORESERVE)
@@ -1015,12 +852,10 @@ void ELFObjectWriter::computeSymbolTable(
}
// Sections have their own string table
- if (MCELF::GetType(SD) != ELF::STT_SECTION)
+ if (Symbol.getType() != ELF::STT_SECTION)
MSD.Name = StrTabBuilder.add(Name);
- if (MSD.SectionIndex == ELF::SHN_UNDEF)
- UndefinedSymbolData.push_back(MSD);
- else if (Local)
+ if (Local)
LocalSymbolData.push_back(MSD);
else
ExternalSymbolData.push_back(MSD);
@@ -1033,38 +868,60 @@ void ELFObjectWriter::computeSymbolTable(
SymtabShndxSection->setAlignment(4);
}
- for (auto i = Asm.file_names_begin(), e = Asm.file_names_end(); i != e; ++i)
- StrTabBuilder.add(*i);
+ ArrayRef<std::string> FileNames = Asm.getFileNames();
+ for (const std::string &Name : FileNames)
+ StrTabBuilder.add(Name);
StrTabBuilder.finalize(StringTableBuilder::ELF);
- for (auto i = Asm.file_names_begin(), e = Asm.file_names_end(); i != e; ++i)
- FileSymbolData.push_back(StrTabBuilder.getOffset(*i));
-
- for (ELFSymbolData &MSD : LocalSymbolData)
- MSD.StringIndex = MCELF::GetType(MSD.Symbol->getData()) == ELF::STT_SECTION
- ? 0
- : StrTabBuilder.getOffset(MSD.Name);
- for (ELFSymbolData &MSD : ExternalSymbolData)
- MSD.StringIndex = StrTabBuilder.getOffset(MSD.Name);
- for (ELFSymbolData& MSD : UndefinedSymbolData)
- MSD.StringIndex = StrTabBuilder.getOffset(MSD.Name);
+ for (const std::string &Name : FileNames)
+ Writer.writeSymbol(StrTabBuilder.getOffset(Name),
+ ELF::STT_FILE | ELF::STB_LOCAL, 0, 0, ELF::STV_DEFAULT,
+ ELF::SHN_ABS, true);
// Symbols are required to be in lexicographic order.
array_pod_sort(LocalSymbolData.begin(), LocalSymbolData.end());
array_pod_sort(ExternalSymbolData.begin(), ExternalSymbolData.end());
- array_pod_sort(UndefinedSymbolData.begin(), UndefinedSymbolData.end());
// Set the symbol indices. Local symbols must come before all other
// symbols with non-local bindings.
- unsigned Index = FileSymbolData.size() + 1;
- for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
- LocalSymbolData[i].Symbol->setIndex(Index++);
-
- for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
- ExternalSymbolData[i].Symbol->setIndex(Index++);
- for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
- UndefinedSymbolData[i].Symbol->setIndex(Index++);
+ unsigned Index = FileNames.size() + 1;
+
+ for (ELFSymbolData &MSD : LocalSymbolData) {
+ unsigned StringIndex = MSD.Symbol->getType() == ELF::STT_SECTION
+ ? 0
+ : StrTabBuilder.getOffset(MSD.Name);
+ MSD.Symbol->setIndex(Index++);
+ writeSymbol(Writer, StringIndex, MSD, Layout);
+ }
+
+ // Write the symbol table entries.
+ LastLocalSymbolIndex = Index;
+
+ for (ELFSymbolData &MSD : ExternalSymbolData) {
+ unsigned StringIndex = StrTabBuilder.getOffset(MSD.Name);
+ MSD.Symbol->setIndex(Index++);
+ writeSymbol(Writer, StringIndex, MSD, Layout);
+ assert(MSD.Symbol->getBinding() != ELF::STB_LOCAL);
+ }
+
+ uint64_t SecEnd = OS.tell();
+ SectionOffsets[SymtabSection] = std::make_pair(SecStart, SecEnd);
+
+ ArrayRef<uint32_t> ShndxIndexes = Writer.getShndxIndexes();
+ if (ShndxIndexes.empty()) {
+ assert(SymtabShndxSectionIndex == 0);
+ return;
+ }
+ assert(SymtabShndxSectionIndex != 0);
+
+ SecStart = OS.tell();
+ const MCSectionELF *SymtabShndxSection =
+ SectionTable[SymtabShndxSectionIndex - 1];
+ for (uint32_t Index : ShndxIndexes)
+ write(Index);
+ SecEnd = OS.tell();
+ SectionOffsets[SymtabShndxSection] = std::make_pair(SecStart, SecEnd);
}
MCSectionELF *
@@ -1182,14 +1039,14 @@ void ELFObjectWriter::WriteSecHdrEntry(uint32_t Name, uint32_t Type,
uint32_t Link, uint32_t Info,
uint64_t Alignment,
uint64_t EntrySize) {
- Write32(Name); // sh_name: index into string table
- Write32(Type); // sh_type
+ write32(Name); // sh_name: index into string table
+ write32(Type); // sh_type
WriteWord(Flags); // sh_flags
WriteWord(Address); // sh_addr
WriteWord(Offset); // sh_offset
WriteWord(Size); // sh_size
- Write32(Link); // sh_link
- Write32(Info); // sh_info
+ write32(Link); // sh_link
+ write32(Info); // sh_info
WriteWord(Alignment); // sh_addralign
WriteWord(EntrySize); // sh_entsize
}
@@ -1204,8 +1061,7 @@ void ELFObjectWriter::writeRelocations(const MCAssembler &Asm,
for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
const ELFRelocationEntry &Entry = Relocs[e - i - 1];
- unsigned Index =
- Entry.Symbol ? getSymbolIndexInSymbolTable(Asm, Entry.Symbol) : 0;
+ unsigned Index = Entry.Symbol ? Entry.Symbol->getIndex() : 0;
if (is64Bit()) {
write(Entry.Offset);
@@ -1292,8 +1148,7 @@ void ELFObjectWriter::writeSection(const SectionIndexMapTy &SectionIndexMap,
}
void ELFObjectWriter::writeSectionHeader(
- const MCAssembler &Asm, const MCAsmLayout &Layout,
- const SectionIndexMapTy &SectionIndexMap,
+ const MCAsmLayout &Layout, const SectionIndexMapTy &SectionIndexMap,
const SectionOffsetsTy &SectionOffsets) {
const unsigned NumSections = SectionTable.size();
@@ -1308,7 +1163,7 @@ void ELFObjectWriter::writeSectionHeader(
if (Type != ELF::SHT_GROUP)
GroupSymbolIndex = 0;
else
- GroupSymbolIndex = getSymbolIndexInSymbolTable(Asm, Section->getGroup());
+ GroupSymbolIndex = Section->getGroup()->getIndex();
const std::pair<uint64_t, uint64_t> &Offsets =
SectionOffsets.find(Section)->second;
@@ -1323,7 +1178,7 @@ void ELFObjectWriter::writeSectionHeader(
}
}
-void ELFObjectWriter::WriteObject(MCAssembler &Asm,
+void ELFObjectWriter::writeObject(MCAssembler &Asm,
const MCAsmLayout &Layout) {
MCContext &Ctx = Asm.getContext();
MCSectionELF *StrtabSection =
@@ -1345,13 +1200,12 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
for (MCSection &Sec : Asm) {
MCSectionELF &Section = static_cast<MCSectionELF &>(Sec);
- uint64_t Padding = OffsetToAlignment(OS.tell(), Section.getAlignment());
- WriteZeros(Padding);
+ align(Section.getAlignment());
// Remember the offset into the file for this section.
uint64_t SecStart = OS.tell();
- const MCSymbol *SignatureSymbol = Section.getGroup();
+ const MCSymbolELF *SignatureSymbol = Section.getGroup();
writeSectionData(Asm, Section, Layout);
uint64_t SecEnd = OS.tell();
@@ -1360,7 +1214,7 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
MCSectionELF *RelSection = createRelocationSection(Ctx, Section);
if (SignatureSymbol) {
- Asm.getOrCreateSymbolData(*SignatureSymbol);
+ Asm.registerSymbol(*SignatureSymbol);
unsigned &GroupIdx = RevGroupMap[SignatureSymbol];
if (!GroupIdx) {
MCSectionELF *Group = Ctx.createELFGroupSection(SignatureSymbol);
@@ -1368,9 +1222,11 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
Group->setAlignment(4);
Groups.push_back(Group);
}
- GroupMembers[SignatureSymbol].push_back(&Section);
+ std::vector<const MCSectionELF *> &Members =
+ GroupMembers[SignatureSymbol];
+ Members.push_back(&Section);
if (RelSection)
- GroupMembers[SignatureSymbol].push_back(RelSection);
+ Members.push_back(RelSection);
}
SectionIndexMap[&Section] = addToSectionTable(&Section);
@@ -1381,8 +1237,7 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
}
for (MCSectionELF *Group : Groups) {
- uint64_t Padding = OffsetToAlignment(OS.tell(), Group->getAlignment());
- WriteZeros(Padding);
+ align(Group->getAlignment());
// Remember the offset into the file for this section.
uint64_t SecStart = OS.tell();
@@ -1400,11 +1255,10 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
}
// Compute symbol table information.
- computeSymbolTable(Asm, Layout, SectionIndexMap, RevGroupMap);
+ computeSymbolTable(Asm, Layout, SectionIndexMap, RevGroupMap, SectionOffsets);
for (MCSectionELF *RelSection : Relocations) {
- uint64_t Padding = OffsetToAlignment(OS.tell(), RelSection->getAlignment());
- WriteZeros(Padding);
+ align(RelSection->getAlignment());
// Remember the offset into the file for this section.
uint64_t SecStart = OS.tell();
@@ -1415,8 +1269,6 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
SectionOffsets[RelSection] = std::make_pair(SecStart, SecEnd);
}
- writeSymbolTable(Ctx, Layout, SectionOffsets);
-
{
uint64_t SecStart = OS.tell();
const MCSectionELF *Sec = createStringTable(Ctx);
@@ -1425,13 +1277,12 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
}
uint64_t NaturalAlignment = is64Bit() ? 8 : 4;
- uint64_t Padding = OffsetToAlignment(OS.tell(), NaturalAlignment);
- WriteZeros(Padding);
+ align(NaturalAlignment);
const unsigned SectionHeaderOffset = OS.tell();
// ... then the section header table ...
- writeSectionHeader(Asm, Layout, SectionIndexMap, SectionOffsets);
+ writeSectionHeader(Layout, SectionIndexMap, SectionOffsets);
uint16_t NumSections = (SectionTable.size() + 1 >= ELF::SHN_LORESERVE)
? (uint16_t)ELF::SHN_UNDEF
@@ -1459,21 +1310,22 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
NumSectionsOffset);
}
-bool ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
- const MCAssembler &Asm, const MCSymbol &SymA, const MCFragment &FB,
+bool ELFObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
+ const MCAssembler &Asm, const MCSymbol &SA, const MCFragment &FB,
bool InSet, bool IsPCRel) const {
+ const auto &SymA = cast<MCSymbolELF>(SA);
if (IsPCRel) {
assert(!InSet);
- if (::isWeak(SymA.getData()))
+ if (::isWeak(SymA))
return false;
}
- return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(Asm, SymA, FB,
+ return MCObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(Asm, SymA, FB,
InSet, IsPCRel);
}
-bool ELFObjectWriter::isWeak(const MCSymbol &Sym) const {
- const MCSymbolData &SD = Sym.getData();
- if (::isWeak(SD))
+bool ELFObjectWriter::isWeak(const MCSymbol &S) const {
+ const auto &Sym = cast<MCSymbolELF>(S);
+ if (::isWeak(Sym))
return true;
// It is invalid to replace a reference to a global in a comdat
@@ -1482,7 +1334,7 @@ bool ELFObjectWriter::isWeak(const MCSymbol &Sym) const {
// We could try to return false for more cases, like the reference
// being in the same comdat or Sym being an alias to another global,
// but it is not clear if it is worth the effort.
- if (MCELF::GetBinding(SD) != ELF::STB_GLOBAL)
+ if (Sym.getBinding() != ELF::STB_GLOBAL)
return false;
if (!Sym.isInSection())
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