//
//===----------------------------------------------------------------------===//
-#include "llvm/MC/ELFObjectWriter.h"
+#include "ELFObjectWriter.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/Twine.h"
-#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCContext.h"
-#include "llvm/MC/MCELFSymbolFlags.h"
#include "llvm/MC/MCExpr.h"
-#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSectionELF.h"
-#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ELF.h"
#include "llvm/Target/TargetAsmBackend.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/ADT/Statistic.h"
#include "../Target/X86/X86FixupKinds.h"
+#include "../Target/ARM/ARMFixupKinds.h"
#include <vector>
using namespace llvm;
-namespace {
+#undef DEBUG_TYPE
+#define DEBUG_TYPE "reloc-info"
- 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;
- }
-
-
- /// ELFSymbolData - Helper struct for containing some precomputed information
- /// on symbols.
- struct ELFSymbolData {
- MCSymbolData *SymbolData;
- uint64_t StringIndex;
- uint32_t SectionIndex;
-
- // Support lexicographic sorting.
- bool operator<(const ELFSymbolData &RHS) const {
- const std::string &Name = SymbolData->getSymbol().getName();
- return Name < RHS.SymbolData->getSymbol().getName();
- }
- };
-
- /// @name Relocation Data
- /// @{
-
- struct ELFRelocationEntry {
- // Make these big enough for both 32-bit and 64-bit
- uint64_t r_offset;
- uint64_t r_info;
- uint64_t r_addend;
-
- // Support lexicographic sorting.
- bool operator<(const ELFRelocationEntry &RE) const {
- return RE.r_offset < r_offset;
- }
- };
-
- llvm::DenseMap<const MCSectionData*,
- std::vector<ELFRelocationEntry> > Relocations;
- DenseMap<const MCSection*, uint64_t> SectionStringTableIndex;
-
- /// @}
- /// @name Symbol Table Data
- /// @{
-
- SmallString<256> StringTable;
- std::vector<ELFSymbolData> LocalSymbolData;
- std::vector<ELFSymbolData> ExternalSymbolData;
- std::vector<ELFSymbolData> UndefinedSymbolData;
-
- /// @}
-
- ELFObjectWriter *Writer;
-
- raw_ostream &OS;
-
- // This holds the current offset into the object file.
- size_t FileOff;
-
- unsigned Is64Bit : 1;
-
- bool HasRelocationAddend;
-
- // This holds the symbol table index of the last local symbol.
- unsigned LastLocalSymbolIndex;
- // This holds the .strtab section index.
- unsigned StringTableIndex;
-
- unsigned ShstrtabIndex;
-
- public:
- ELFObjectWriterImpl(ELFObjectWriter *_Writer, bool _Is64Bit,
- bool _HasRelAddend)
- : Writer(_Writer), OS(Writer->getStream()), FileOff(0),
- Is64Bit(_Is64Bit), HasRelocationAddend(_HasRelAddend) {
- }
-
- void Write8(uint8_t Value) { Writer->Write8(Value); }
- void Write16(uint16_t Value) { Writer->Write16(Value); }
- void Write32(uint32_t Value) { Writer->Write32(Value); }
- void Write64(uint64_t Value) { Writer->Write64(Value); }
- void WriteZeros(unsigned N) { Writer->WriteZeros(N); }
- void WriteBytes(StringRef Str, unsigned ZeroFillSize = 0) {
- Writer->WriteBytes(Str, ZeroFillSize);
- }
-
- void WriteWord(uint64_t W) {
- if (Is64Bit) {
- Writer->Write64(W);
- } else {
- Writer->Write32(W);
- }
- }
-
- void String8(char *buf, uint8_t Value) {
- buf[0] = Value;
- }
-
- void StringLE16(char *buf, uint16_t Value) {
- buf[0] = char(Value >> 0);
- buf[1] = char(Value >> 8);
- }
-
- void StringLE32(char *buf, uint32_t Value) {
- buf[0] = char(Value >> 0);
- buf[1] = char(Value >> 8);
- buf[2] = char(Value >> 16);
- buf[3] = char(Value >> 24);
- }
-
- void StringLE64(char *buf, uint64_t Value) {
- buf[0] = char(Value >> 0);
- buf[1] = char(Value >> 8);
- buf[2] = char(Value >> 16);
- buf[3] = char(Value >> 24);
- buf[4] = char(Value >> 32);
- buf[5] = char(Value >> 40);
- buf[6] = char(Value >> 48);
- buf[7] = char(Value >> 56);
- }
-
- void StringBE16(char *buf ,uint16_t Value) {
- buf[0] = char(Value >> 8);
- buf[1] = char(Value >> 0);
- }
-
- void StringBE32(char *buf, uint32_t Value) {
- buf[0] = char(Value >> 24);
- buf[1] = char(Value >> 16);
- buf[2] = char(Value >> 8);
- buf[3] = char(Value >> 0);
- }
-
- void StringBE64(char *buf, uint64_t Value) {
- buf[0] = char(Value >> 56);
- buf[1] = char(Value >> 48);
- buf[2] = char(Value >> 40);
- buf[3] = char(Value >> 32);
- buf[4] = char(Value >> 24);
- buf[5] = char(Value >> 16);
- buf[6] = char(Value >> 8);
- buf[7] = char(Value >> 0);
- }
-
- void String16(char *buf, uint16_t Value) {
- if (Writer->isLittleEndian())
- StringLE16(buf, Value);
- else
- StringBE16(buf, Value);
- }
-
- void String32(char *buf, uint32_t Value) {
- if (Writer->isLittleEndian())
- StringLE32(buf, Value);
- else
- StringBE32(buf, Value);
- }
-
- void String64(char *buf, uint64_t Value) {
- if (Writer->isLittleEndian())
- StringLE64(buf, Value);
- else
- StringBE64(buf, Value);
- }
-
- void WriteHeader(uint64_t SectionDataSize, unsigned NumberOfSections);
-
- void WriteSymbolEntry(MCDataFragment *F, uint64_t name, uint8_t info,
- uint64_t value, uint64_t size,
- uint8_t other, uint16_t shndx);
-
- void WriteSymbol(MCDataFragment *F, ELFSymbolData &MSD,
- const MCAsmLayout &Layout);
-
- void WriteSymbolTable(MCDataFragment *F, const MCAssembler &Asm,
- const MCAsmLayout &Layout);
-
- void RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
- const MCFragment *Fragment, const MCFixup &Fixup,
- MCValue Target, uint64_t &FixedValue);
-
- // XXX-PERF: this should be cached
- uint64_t getNumOfLocalSymbols(const MCAssembler &Asm) {
- std::vector<const MCSymbol*> Local;
-
- uint64_t Index = 0;
- for (MCAssembler::const_symbol_iterator it = Asm.symbol_begin(),
- ie = Asm.symbol_end(); it != ie; ++it) {
- const MCSymbol &Symbol = it->getSymbol();
+bool ELFObjectWriter::isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind) {
+ const MCFixupKindInfo &FKI =
+ Asm.getBackend().getFixupKindInfo((MCFixupKind) Kind);
- // Ignore non-linker visible symbols.
- if (!Asm.isSymbolLinkerVisible(Symbol))
- continue;
-
- if (it->isExternal() || Symbol.isUndefined())
- continue;
-
- Index++;
- }
-
- return Index;
- }
-
- uint64_t getSymbolIndexInSymbolTable(MCAssembler &Asm, const MCSymbol *S);
-
- /// 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.
- void ComputeSymbolTable(MCAssembler &Asm);
-
- void WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout,
- const MCSectionData &SD);
-
- void WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout) {
- for (MCAssembler::const_iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it) {
- WriteRelocation(Asm, Layout, *it);
- }
- }
-
- void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout);
-
- void ExecutePostLayoutBinding(MCAssembler &Asm) {}
-
- void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
- uint64_t Address, uint64_t Offset,
- uint64_t Size, uint32_t Link, uint32_t Info,
- uint64_t Alignment, uint64_t EntrySize);
-
- void WriteRelocationsFragment(const MCAssembler &Asm, MCDataFragment *F,
- const MCSectionData *SD);
-
- void WriteObject(const MCAssembler &Asm, const MCAsmLayout &Layout);
- };
+ 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()
+{}
+
// Emit the ELF header.
-void ELFObjectWriterImpl::WriteHeader(uint64_t SectionDataSize,
- unsigned NumberOfSections) {
+void ELFObjectWriter::WriteHeader(uint64_t SectionDataSize,
+ unsigned NumberOfSections) {
// ELF Header
// ----------
//
Write8('L'); // e_ident[EI_MAG2]
Write8('F'); // 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(Writer->isLittleEndian() ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
+ Write8(isLittleEndian() ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
Write8(ELF::EV_CURRENT); // e_ident[EI_VERSION]
- Write8(ELF::ELFOSABI_LINUX); // e_ident[EI_OSABI]
+ // e_ident[EI_OSABI]
+ switch (TargetObjectWriter->getOSType()) {
+ case Triple::FreeBSD: Write8(ELF::ELFOSABI_FREEBSD); break;
+ case Triple::Linux: Write8(ELF::ELFOSABI_LINUX); break;
+ default: Write8(ELF::ELFOSABI_NONE); break;
+ }
Write8(0); // e_ident[EI_ABIVERSION]
WriteZeros(ELF::EI_NIDENT - ELF::EI_PAD);
Write16(ELF::ET_REL); // e_type
- // FIXME: Make this configurable
- Write16(Is64Bit ? ELF::EM_X86_64 : ELF::EM_386); // e_machine = target
+ Write16(TargetObjectWriter->getEMachine()); // e_machine = target
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(SectionDataSize + (Is64Bit ? sizeof(ELF::Elf64_Ehdr) :
+ WriteWord(SectionDataSize + (is64Bit() ? sizeof(ELF::Elf64_Ehdr) :
sizeof(ELF::Elf32_Ehdr))); // e_shoff = sec hdr table off in bytes
- // FIXME: Make this configurable.
- Write32(0); // e_flags = whatever the target wants
+ // e_flags = whatever the target wants
+ WriteEFlags();
// 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
// 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(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,
- uint8_t info, uint64_t value,
- uint64_t size, uint8_t other,
- uint16_t shndx) {
- if (Is64Bit) {
- char buf[8];
+void ELFObjectWriter::WriteSymbolEntry(MCDataFragment *SymtabF,
+ MCDataFragment *ShndxF,
+ uint64_t name,
+ uint8_t info, uint64_t value,
+ uint64_t size, uint8_t other,
+ uint32_t shndx,
+ bool Reserved) {
+ if (ShndxF) {
+ if (shndx >= ELF::SHN_LORESERVE && !Reserved)
+ String32(*ShndxF, shndx);
+ else
+ String32(*ShndxF, 0);
+ }
+
+ uint16_t Index = (shndx >= ELF::SHN_LORESERVE && !Reserved) ?
+ uint16_t(ELF::SHN_XINDEX) : shndx;
+
+ if (is64Bit()) {
+ String32(*SymtabF, name); // st_name
+ String8(*SymtabF, info); // st_info
+ String8(*SymtabF, other); // st_other
+ String16(*SymtabF, Index); // st_shndx
+ String64(*SymtabF, value); // st_value
+ String64(*SymtabF, size); // st_size
+ } else {
+ String32(*SymtabF, name); // st_name
+ String32(*SymtabF, value); // st_value
+ String32(*SymtabF, size); // st_size
+ String8(*SymtabF, info); // st_info
+ String8(*SymtabF, other); // st_other
+ String16(*SymtabF, Index); // st_shndx
+ }
+}
+
+uint64_t ELFObjectWriter::SymbolValue(MCSymbolData &Data,
+ const MCAsmLayout &Layout) {
+ if (Data.isCommon() && Data.isExternal())
+ return Data.getCommonAlignment();
+
+ const MCSymbol &Symbol = Data.getSymbol();
- String32(buf, name);
- F->getContents() += StringRef(buf, 4); // st_name
+ if (Symbol.isAbsolute() && Symbol.isVariable()) {
+ if (const MCExpr *Value = Symbol.getVariableValue()) {
+ int64_t IntValue;
+ if (Value->EvaluateAsAbsolute(IntValue, Layout))
+ return (uint64_t)IntValue;
+ }
+ }
- String8(buf, info);
- F->getContents() += StringRef(buf, 1); // st_info
+ if (!Symbol.isInSection())
+ return 0;
- String8(buf, other);
- F->getContents() += StringRef(buf, 1); // st_other
- String16(buf, shndx);
- F->getContents() += StringRef(buf, 2); // st_shndx
+ if (Data.getFragment()) {
+ if (Data.getFlags() & ELF_Other_ThumbFunc)
+ return Layout.getSymbolOffset(&Data)+1;
+ else
+ return Layout.getSymbolOffset(&Data);
+ }
- String64(buf, value);
- F->getContents() += StringRef(buf, 8); // st_value
+ return 0;
+}
- String64(buf, size);
- F->getContents() += StringRef(buf, 8); // st_size
- } else {
- char buf[4];
+void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
+ const MCAsmLayout &Layout) {
+ // The presence of symbol versions causes undefined symbols and
+ // versions declared with @@@ to be renamed.
- String32(buf, name);
- F->getContents() += StringRef(buf, 4); // st_name
+ for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
+ ie = Asm.symbol_end(); it != ie; ++it) {
+ const MCSymbol &Alias = it->getSymbol();
+ const MCSymbol &Symbol = Alias.AliasedSymbol();
+ MCSymbolData &SD = Asm.getSymbolData(Symbol);
+
+ // Not an alias.
+ if (&Symbol == &Alias)
+ continue;
- String32(buf, value);
- F->getContents() += StringRef(buf, 4); // st_value
+ StringRef AliasName = Alias.getName();
+ size_t Pos = AliasName.find('@');
+ if (Pos == StringRef::npos)
+ continue;
- String32(buf, size);
- F->getContents() += StringRef(buf, 4); // st_size
+ // 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());
+ MCELF::SetBinding(*it, MCELF::GetBinding(SD));
- String8(buf, info);
- F->getContents() += StringRef(buf, 1); // st_info
+ StringRef Rest = AliasName.substr(Pos);
+ if (!Symbol.isUndefined() && !Rest.startswith("@@@"))
+ continue;
- String8(buf, other);
- F->getContents() += StringRef(buf, 1); // st_other
+ // FIXME: produce a better error message.
+ if (Symbol.isUndefined() && Rest.startswith("@@") &&
+ !Rest.startswith("@@@"))
+ report_fatal_error("A @@ version cannot be undefined");
- String16(buf, shndx);
- F->getContents() += StringRef(buf, 2); // st_shndx
+ Renames.insert(std::make_pair(&Symbol, &Alias));
}
}
-void ELFObjectWriterImpl::WriteSymbol(MCDataFragment *F, ELFSymbolData &MSD,
- const MCAsmLayout &Layout) {
- MCSymbolData &Data = *MSD.SymbolData;
- uint8_t Info = (Data.getFlags() & 0xff);
- uint8_t Other = ((Data.getFlags() & 0xf00) >> ELF_STV_Shift);
- uint64_t Value = 0;
+void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF,
+ MCDataFragment *ShndxF,
+ ELFSymbolData &MSD,
+ const MCAsmLayout &Layout) {
+ MCSymbolData &OrigData = *MSD.SymbolData;
+ MCSymbolData &Data =
+ Layout.getAssembler().getSymbolData(OrigData.getSymbol().AliasedSymbol());
+
+ bool IsReserved = Data.isCommon() || Data.getSymbol().isAbsolute() ||
+ Data.getSymbol().isVariable();
+
+ uint8_t Binding = MCELF::GetBinding(OrigData);
+ uint8_t Visibility = MCELF::GetVisibility(OrigData);
+ uint8_t Type = MCELF::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;
- if (Data.isCommon() && Data.isExternal())
- Value = Data.getCommonAlignment();
-
- ESize = Data.getSize();
- if (Data.getSize()) {
- MCValue Res;
- if (ESize->getKind() == MCExpr::Binary) {
- 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);
- Value = Layout.getSymbolAddress(&Data);
- }
- } else if (ESize->getKind() == MCExpr::Constant) {
- Size = static_cast<const MCConstantExpr *>(ESize)->getValue();
- } else {
- assert(0 && "Unsupported size expression");
- }
+ assert(!(Data.isCommon() && !Data.isExternal()));
+
+ const MCExpr *ESize = Data.getSize();
+ if (ESize) {
+ int64_t Res;
+ if (!ESize->EvaluateAsAbsolute(Res, Layout))
+ report_fatal_error("Size expression must be absolute.");
+ Size = Res;
}
// 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,
- const MCAssembler &Asm,
- const MCAsmLayout &Layout) {
+void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF,
+ MCDataFragment *ShndxF,
+ const MCAssembler &Asm,
+ const MCAsmLayout &Layout,
+ const SectionIndexMapTy &SectionIndexMap) {
// The string table must be emitted first because we need the index
// into the string table for all the symbol names.
assert(StringTable.size() && "Missing string table");
// 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 section.
- // leaving out the just added .symtab which is at
- // the very end
- unsigned Index = 1;
- for (MCAssembler::const_iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it, ++Index) {
+ // Write out a symbol table entry for each regular section.
+ for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e;
+ ++i) {
const MCSectionELF &Section =
- static_cast<const MCSectionELF&>(it->getSection());
- // Leave out relocations so we don't have indexes within
- // the relocations messed up
- if (Section.getType() == ELF::SHT_RELA || Section.getType() == ELF::SHT_REL)
- continue;
- if (Index == Asm.size())
+ static_cast<const MCSectionELF&>(i->getSection());
+ if (Section.getType() == ELF::SHT_RELA ||
+ Section.getType() == ELF::SHT_REL ||
+ Section.getType() == ELF::SHT_STRTAB ||
+ Section.getType() == ELF::SHT_SYMTAB)
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, SectionIndexMap.lookup(&Section), 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);
- if (Data.getFlags() & ELF_STB_Local)
+ 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 (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
LastLocalSymbolIndex++;
}
for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) {
ELFSymbolData &MSD = UndefinedSymbolData[i];
MCSymbolData &Data = *MSD.SymbolData;
- Data.setFlags(Data.getFlags() | ELF_STB_Global);
- WriteSymbol(F, MSD, Layout);
- if (Data.getFlags() & ELF_STB_Local)
+ WriteSymbol(SymtabF, ShndxF, MSD, Layout);
+ if (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
LastLocalSymbolIndex++;
}
}
-// FIXME: this is currently X86_64 only
-void ELFObjectWriterImpl::RecordRelocation(const MCAssembler &Asm,
- const MCAsmLayout &Layout,
- const MCFragment *Fragment,
- const MCFixup &Fixup,
- MCValue Target,
- uint64_t &FixedValue) {
- unsigned IsPCRel = isFixupKindX86PCRel(Fixup.getKind());
- ELFRelocationEntry ERE;
- struct ELF::Elf64_Rela ERE64;
-
- uint64_t FixupOffset =
- Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
- int64_t Value;
- int64_t Addend = 0;
- unsigned Index = 0;
- unsigned Type;
+const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm,
+ const MCValue &Target,
+ const MCFragment &F,
+ const MCFixup &Fixup,
+ bool IsPCRel) const {
+ const MCSymbol &Symbol = Target.getSymA()->getSymbol();
+ const MCSymbol &ASymbol = Symbol.AliasedSymbol();
+ const MCSymbol *Renamed = Renames.lookup(&Symbol);
+ const MCSymbolData &SD = Asm.getSymbolData(Symbol);
+
+ if (ASymbol.isUndefined()) {
+ if (Renamed)
+ return Renamed;
+ return &ASymbol;
+ }
- Value = Target.getConstant();
+ if (SD.isExternal()) {
+ if (Renamed)
+ return Renamed;
+ return &Symbol;
+ }
- if (Target.isAbsolute()) {
- Type = ELF::R_X86_64_NONE;
- Index = 0;
- } else {
- const MCSymbol *Symbol = &Target.getSymA()->getSymbol();
- MCSymbolData &SD = Asm.getSymbolData(*Symbol);
- const MCSymbolData *Base = Asm.getAtom(Layout, &SD);
-
- if (Base) {
- Index = getSymbolIndexInSymbolTable(const_cast<MCAssembler &>(Asm), &Base->getSymbol());
- if (Base != &SD)
- Value += Layout.getSymbolAddress(&SD) - Layout.getSymbolAddress(Base);
- Addend = Value;
- Value = 0;
- } else {
- MCFragment *F = SD.getFragment();
- if (F) {
- // Index of the section in .symtab against this symbol
- // is being relocated + 2 (empty section + abs. symbols).
- Index = SD.getFragment()->getParent()->getOrdinal() +
- getNumOfLocalSymbols(Asm) + 1;
-
- MCSectionData *FSD = F->getParent();
- // Offset of the symbol in the section
- Addend = Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD);
- } else {
- FixedValue = Value;
- return;
- }
- }
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF&>(ASymbol.getSection());
+ const SectionKind secKind = Section.getKind();
+
+ if (secKind.isBSS())
+ return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
+
+ if (secKind.isThreadLocal()) {
+ if (Renamed)
+ return Renamed;
+ return &Symbol;
}
- // determine the type of the relocation
- if (IsPCRel) {
- Type = ELF::R_X86_64_PC32;
- } else {
- switch ((unsigned)Fixup.getKind()) {
- default: llvm_unreachable("invalid fixup kind!");
- case FK_Data_8: Type = ELF::R_X86_64_64; break;
- case X86::reloc_pcrel_4byte:
- case FK_Data_4:
- // check that the offset fits within a signed long
- if (isInt<32>(Target.getConstant()))
- Type = ELF::R_X86_64_32S;
+ MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind();
+ const MCSectionELF &Sec2 =
+ static_cast<const MCSectionELF&>(F.getParent()->getSection());
+
+ if (&Sec2 != &Section &&
+ (Kind == MCSymbolRefExpr::VK_PLT ||
+ Kind == MCSymbolRefExpr::VK_GOTPCREL ||
+ Kind == MCSymbolRefExpr::VK_GOTOFF)) {
+ if (Renamed)
+ return Renamed;
+ return &Symbol;
+ }
+
+ if (Section.getFlags() & ELF::SHF_MERGE) {
+ if (Target.getConstant() == 0)
+ return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
+ if (Renamed)
+ return Renamed;
+ return &Symbol;
+ }
+
+ return ExplicitRelSym(Asm, Target, F, Fixup, IsPCRel);
+
+}
+
+
+void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
+ const MCAsmLayout &Layout,
+ const MCFragment *Fragment,
+ const MCFixup &Fixup,
+ MCValue Target,
+ uint64_t &FixedValue) {
+ int64_t Addend = 0;
+ int Index = 0;
+ int64_t Value = Target.getConstant();
+ const MCSymbol *RelocSymbol = NULL;
+
+ bool IsPCRel = isFixupKindPCRel(Asm, Fixup.getKind());
+ if (!Target.isAbsolute()) {
+ const MCSymbol &Symbol = Target.getSymA()->getSymbol();
+ const MCSymbol &ASymbol = Symbol.AliasedSymbol();
+ RelocSymbol = SymbolToReloc(Asm, Target, *Fragment, Fixup, IsPCRel);
+
+ if (const MCSymbolRefExpr *RefB = Target.getSymB()) {
+ const MCSymbol &SymbolB = RefB->getSymbol();
+ MCSymbolData &SDB = Asm.getSymbolData(SymbolB);
+ IsPCRel = true;
+
+ // Offset of the symbol in the section
+ int64_t a = Layout.getSymbolOffset(&SDB);
+
+ // Ofeset of the relocation in the section
+ int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
+ Value += b - a;
+ }
+
+ if (!RelocSymbol) {
+ 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);
+ } else {
+ if (Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
+ WeakrefUsedInReloc.insert(RelocSymbol);
else
- Type = ELF::R_X86_64_32;
- break;
- case FK_Data_2: Type = ELF::R_X86_64_16; break;
- case X86::reloc_pcrel_1byte:
- case FK_Data_1:
- Type = ELF::R_X86_64_8;
- break;
+ UsedInReloc.insert(RelocSymbol);
+ Index = -1;
}
+ Addend = Value;
+ // Compensate for the addend on i386.
+ if (is64Bit())
+ Value = 0;
}
FixedValue = Value;
+ unsigned Type = GetRelocType(Target, Fixup, IsPCRel,
+ (RelocSymbol != 0), Addend);
- ERE64.setSymbolAndType(Index, Type);
-
- ERE.r_offset = FixupOffset;
- ERE.r_info = ERE64.r_info;
- if (HasRelocationAddend)
- ERE.r_addend = Addend;
- else
- ERE.r_addend = 0; // Silence compiler warning.
+ uint64_t RelocOffset = Layout.getFragmentOffset(Fragment) +
+ Fixup.getOffset();
+ if (!hasRelocationAddend())
+ Addend = 0;
+ ELFRelocationEntry ERE(RelocOffset, Index, Type, RelocSymbol, Addend);
Relocations[Fragment->getParent()].push_back(ERE);
}
-// XXX-PERF: this should be cached
-uint64_t ELFObjectWriterImpl::getSymbolIndexInSymbolTable(MCAssembler &Asm,
- const MCSymbol *S) {
- std::vector<ELFSymbolData> Local;
- std::vector<ELFSymbolData> External;
- std::vector<ELFSymbolData> Undefined;
- for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
- ie = Asm.symbol_end(); it != ie; ++it) {
- const MCSymbol &Symbol = it->getSymbol();
+uint64_t
+ELFObjectWriter::getSymbolIndexInSymbolTable(const MCAssembler &Asm,
+ const MCSymbol *S) {
+ MCSymbolData &SD = Asm.getSymbolData(*S);
+ return SD.getIndex();
+}
- // Ignore non-linker visible symbols.
- if (!Asm.isSymbolLinkerVisible(Symbol))
- continue;
+bool ELFObjectWriter::isInSymtab(const MCAssembler &Asm,
+ const MCSymbolData &Data,
+ bool Used, bool Renamed) {
+ if (Data.getFlags() & ELF_Other_Weakref)
+ return false;
- if (it->isExternal() || Symbol.isUndefined())
- continue;
+ if (Used)
+ return true;
- ELFSymbolData MSD;
- MSD.SymbolData = it;
+ if (Renamed)
+ return false;
- Local.push_back(MSD);
- }
- for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
- ie = Asm.symbol_end(); it != ie; ++it) {
- const MCSymbol &Symbol = it->getSymbol();
+ const MCSymbol &Symbol = Data.getSymbol();
- // Ignore non-linker visible symbols.
- if (!Asm.isSymbolLinkerVisible(Symbol))
- continue;
+ if (Symbol.getName() == "_GLOBAL_OFFSET_TABLE_")
+ return true;
- if (!it->isExternal() && !Symbol.isUndefined())
- continue;
+ const MCSymbol &A = Symbol.AliasedSymbol();
+ if (Symbol.isVariable() && !A.isVariable() && A.isUndefined())
+ return false;
- ELFSymbolData MSD;
- MSD.SymbolData = it;
+ bool IsGlobal = MCELF::GetBinding(Data) == ELF::STB_GLOBAL;
+ if (!Symbol.isVariable() && Symbol.isUndefined() && !IsGlobal)
+ return false;
- if (Symbol.isUndefined())
- Undefined.push_back(MSD);
- else
- External.push_back(MSD);
+ if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
+ return false;
+
+ if (Symbol.isTemporary())
+ return false;
+
+ return true;
+}
+
+bool ELFObjectWriter::isLocal(const MCSymbolData &Data, bool isSignature,
+ bool isUsedInReloc) {
+ if (Data.isExternal())
+ return false;
+
+ const MCSymbol &Symbol = Data.getSymbol();
+ const MCSymbol &RefSymbol = Symbol.AliasedSymbol();
+
+ if (RefSymbol.isUndefined() && !RefSymbol.isVariable()) {
+ if (isSignature && !isUsedInReloc)
+ return true;
+
+ return false;
}
- array_pod_sort(Local.begin(), Local.end());
- array_pod_sort(External.begin(), External.end());
- array_pod_sort(Undefined.begin(), Undefined.end());
-
- for (unsigned i = 0, e = Local.size(); i != e; ++i)
- if (&Local[i].SymbolData->getSymbol() == S)
- return i + /* empty symbol */ 1;
- for (unsigned i = 0, e = External.size(); i != e; ++i)
- if (&External[i].SymbolData->getSymbol() == S)
- return i + Local.size() + Asm.size() + /* empty symbol */ 1;
- for (unsigned i = 0, e = Undefined.size(); i != e; ++i)
- if (&Undefined[i].SymbolData->getSymbol() == S)
- return i + Local.size() + External.size() + Asm.size() + /* empty symbol */ 1;
-
- llvm_unreachable("Cannot find symbol which should exist!");
+ return true;
}
-void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) {
- // Build section lookup table.
- DenseMap<const MCSection*, uint8_t> SectionIndexMap;
+void ELFObjectWriter::ComputeIndexMap(MCAssembler &Asm,
+ SectionIndexMapTy &SectionIndexMap,
+ const RelMapTy &RelMap) {
unsigned Index = 1;
for (MCAssembler::iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it, ++Index)
- SectionIndexMap[&it->getSection()] = Index;
+ ie = Asm.end(); it != ie; ++it) {
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF &>(it->getSection());
+ if (Section.getType() != ELF::SHT_GROUP)
+ continue;
+ SectionIndexMap[&Section] = Index++;
+ }
+
+ for (MCAssembler::iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF &>(it->getSection());
+ if (Section.getType() == ELF::SHT_GROUP ||
+ Section.getType() == ELF::SHT_REL ||
+ Section.getType() == ELF::SHT_RELA)
+ continue;
+ SectionIndexMap[&Section] = Index++;
+ const MCSectionELF *RelSection = RelMap.lookup(&Section);
+ if (RelSection)
+ SectionIndexMap[RelSection] = Index++;
+ }
+}
+
+void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm,
+ 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) {
+ llvm::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);
+ }
// Index 0 is always the empty string.
StringMap<uint64_t> StringIndexMap;
StringTable += '\x00';
- // Add the data for local symbols.
+ // FIXME: We could optimize suffixes in strtab in the same way we
+ // optimize them in shstrtab.
+
+ // 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;
+ bool Used = UsedInReloc.count(&Symbol);
+ bool WeakrefUsed = WeakrefUsedInReloc.count(&Symbol);
+ bool isSignature = RevGroupMap.count(&Symbol);
- if (it->isExternal() || Symbol.isUndefined())
+ if (!isInSymtab(Asm, *it,
+ Used || WeakrefUsed || isSignature,
+ 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;
+ const MCSymbol &RefSymbol = Symbol.AliasedSymbol();
+
+ // 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);
+ MCELF::SetBinding(*it, ELF::STB_GLOBAL);
+ MCELF::SetBinding(SD, ELF::STB_GLOBAL);
+ }
+
+ if (RefSymbol.isUndefined() && !Used && WeakrefUsed)
+ MCELF::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()) {
+ if (isSignature && !Used)
+ MSD.SectionIndex = SectionIndexMap.lookup(RevGroupMap[&Symbol]);
+ else
+ MSD.SectionIndex = ELF::SHN_UNDEF;
} else {
- MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection());
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF&>(RefSymbol.getSection());
+ MSD.SectionIndex = SectionIndexMap.lookup(&Section);
+ 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))
- continue;
- if (!it->isExternal() && !Symbol.isUndefined())
- continue;
+ // The @@@ in symbol version is replaced with @ in undefined symbols and
+ // @@ in defined ones.
+ StringRef Name = Symbol.getName();
+ SmallString<32> Buf;
+
+ size_t Pos = Name.find("@@@");
+ if (Pos != StringRef::npos) {
+ Buf += Name.substr(0, Pos);
+ unsigned Skip = MSD.SectionIndex == ELF::SHN_UNDEF ? 2 : 1;
+ Buf += Name.substr(Pos + Skip);
+ Name = Buf;
+ }
- uint64_t &Entry = StringIndexMap[Symbol.getName()];
+ uint64_t &Entry = StringIndexMap[Name];
if (!Entry) {
Entry = StringTable.size();
- StringTable += Symbol.getName();
+ StringTable += Name;
StringTable += '\x00';
}
-
- ELFSymbolData MSD;
- MSD.SymbolData = it;
MSD.StringIndex = Entry;
-
- if (Symbol.isUndefined()) {
- MSD.SectionIndex = ELF::SHN_UNDEF;
- // XXX: for some reason we dont Emit* this
- it->setFlags(it->getFlags() | 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 if (it->isCommon()) {
- MSD.SectionIndex = ELF::SHN_COMMON;
- 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.
// Set the symbol indices. Local symbols must come before all other
// symbols with non-local bindings.
- Index = 0;
+ unsigned Index = 1;
for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
LocalSymbolData[i].SymbolData->setIndex(Index++);
+
+ Index += NumRegularSections;
+
for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
ExternalSymbolData[i].SymbolData->setIndex(Index++);
for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
UndefinedSymbolData[i].SymbolData->setIndex(Index++);
}
-void ELFObjectWriterImpl::WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout,
- const MCSectionData &SD) {
- if (!Relocations[&SD].empty()) {
+void ELFObjectWriter::CreateRelocationSections(MCAssembler &Asm,
+ MCAsmLayout &Layout,
+ RelMapTy &RelMap) {
+ for (MCAssembler::const_iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ const MCSectionData &SD = *it;
+ if (Relocations[&SD].empty())
+ continue;
+
MCContext &Ctx = Asm.getContext();
- const MCSection *RelaSection;
const MCSectionELF &Section =
static_cast<const MCSectionELF&>(SD.getSection());
const StringRef SectionName = Section.getSectionName();
- std::string RelaSectionName = HasRelocationAddend ? ".rela" : ".rel";
-
+ std::string RelaSectionName = hasRelocationAddend() ? ".rela" : ".rel";
RelaSectionName += SectionName;
- unsigned EntrySize = Is64Bit ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
- RelaSection = Ctx.getELFSection(RelaSectionName, HasRelocationAddend ?
- ELF::SHT_RELA : ELF::SHT_REL, 0,
- SectionKind::getReadOnly(),
- false, EntrySize);
+ unsigned EntrySize;
+ if (hasRelocationAddend())
+ EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rela) : sizeof(ELF::Elf32_Rela);
+ else
+ EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel);
+
+ const MCSectionELF *RelaSection =
+ Ctx.getELFSection(RelaSectionName, hasRelocationAddend() ?
+ ELF::SHT_RELA : ELF::SHT_REL, 0,
+ SectionKind::getReadOnly(),
+ EntrySize, "");
+ RelMap[&Section] = RelaSection;
+ Asm.getOrCreateSectionData(*RelaSection);
+ }
+}
+
+void ELFObjectWriter::WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout,
+ const RelMapTy &RelMap) {
+ for (MCAssembler::const_iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ const MCSectionData &SD = *it;
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF&>(SD.getSection());
+ const MCSectionELF *RelaSection = RelMap.lookup(&Section);
+ if (!RelaSection)
+ continue;
MCSectionData &RelaSD = Asm.getOrCreateSectionData(*RelaSection);
- RelaSD.setAlignment(1);
+ RelaSD.setAlignment(is64Bit() ? 8 : 4);
MCDataFragment *F = new MCDataFragment(&RelaSD);
-
- WriteRelocationsFragment(Asm, F, &SD);
-
- Asm.AddSectionToTheEnd(RelaSD, Layout);
+ WriteRelocationsFragment(Asm, F, &*it);
}
}
-void ELFObjectWriterImpl::WriteSecHdrEntry(uint32_t Name, uint32_t Type,
- uint64_t Flags, uint64_t Address,
- uint64_t Offset, uint64_t Size,
- uint32_t Link, uint32_t Info,
- uint64_t Alignment,
- uint64_t EntrySize) {
+void ELFObjectWriter::WriteSecHdrEntry(uint32_t Name, uint32_t Type,
+ uint64_t Flags, uint64_t Address,
+ uint64_t Offset, uint64_t Size,
+ uint32_t Link, uint32_t Info,
+ uint64_t Alignment,
+ uint64_t EntrySize) {
Write32(Name); // sh_name: index into string table
Write32(Type); // sh_type
WriteWord(Flags); // sh_flags
WriteWord(EntrySize); // sh_entsize
}
-void ELFObjectWriterImpl::WriteRelocationsFragment(const MCAssembler &Asm,
- MCDataFragment *F,
- const MCSectionData *SD) {
+void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm,
+ MCDataFragment *F,
+ const MCSectionData *SD) {
std::vector<ELFRelocationEntry> &Relocs = Relocations[SD];
// sort by the r_offset just like gnu as does
array_pod_sort(Relocs.begin(), Relocs.end());
for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
ELFRelocationEntry entry = Relocs[e - i - 1];
- unsigned WordSize = Is64Bit ? 8 : 4;
- F->getContents() += StringRef((const char *)&entry.r_offset, WordSize);
- F->getContents() += StringRef((const char *)&entry.r_info, WordSize);
+ if (!entry.Index)
+ ;
+ else if (entry.Index < 0)
+ entry.Index = getSymbolIndexInSymbolTable(Asm, entry.Symbol);
+ else
+ entry.Index += LocalSymbolData.size();
+ if (is64Bit()) {
+ String64(*F, entry.r_offset);
+
+ struct ELF::Elf64_Rela ERE64;
+ ERE64.setSymbolAndType(entry.Index, entry.Type);
+ String64(*F, ERE64.r_info);
+
+ if (hasRelocationAddend())
+ String64(*F, entry.r_addend);
+ } else {
+ String32(*F, entry.r_offset);
+
+ struct ELF::Elf32_Rela ERE32;
+ ERE32.setSymbolAndType(entry.Index, entry.Type);
+ String32(*F, ERE32.r_info);
+
+ if (hasRelocationAddend())
+ String32(*F, entry.r_addend);
+ }
+ }
+}
- if (HasRelocationAddend)
- F->getContents() += StringRef((const char *)&entry.r_addend, WordSize);
+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();
+ const unsigned sizeA = NameA.size();
+ const unsigned sizeB = NameB.size();
+ const unsigned len = std::min(sizeA, sizeB);
+ for (unsigned int i = 0; i < len; ++i) {
+ char ca = NameA[sizeA - i - 1];
+ char cb = NameB[sizeB - i - 1];
+ if (ca != cb)
+ return cb - ca;
}
+
+ return sizeB - sizeA;
}
-void ELFObjectWriterImpl::CreateMetadataSections(MCAssembler &Asm,
- MCAsmLayout &Layout) {
+void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm,
+ MCAsmLayout &Layout,
+ SectionIndexMapTy &SectionIndexMap,
+ const RelMapTy &RelMap) {
MCContext &Ctx = Asm.getContext();
MCDataFragment *F;
- WriteRelocations(Asm, Layout);
-
- const MCSection *SymtabSection;
- unsigned EntrySize = Is64Bit ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
+ unsigned EntrySize = is64Bit() ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
- SymtabSection = Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
- SectionKind::getReadOnly(),
- false, EntrySize);
+ // We construct .shstrtab, .symtab and .strtab in this order to match gnu as.
+ const MCSectionELF *ShstrtabSection =
+ Ctx.getELFSection(".shstrtab", ELF::SHT_STRTAB, 0,
+ SectionKind::getReadOnly());
+ MCSectionData &ShstrtabSD = Asm.getOrCreateSectionData(*ShstrtabSection);
+ ShstrtabSD.setAlignment(1);
+ const MCSectionELF *SymtabSection =
+ Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
+ SectionKind::getReadOnly(),
+ EntrySize, "");
MCSectionData &SymtabSD = Asm.getOrCreateSectionData(*SymtabSection);
+ SymtabSD.setAlignment(is64Bit() ? 8 : 4);
- SymtabSD.setAlignment(Is64Bit ? 8 : 4);
-
- F = new MCDataFragment(&SymtabSD);
+ MCSectionData *SymtabShndxSD = NULL;
- // Symbol table
- WriteSymbolTable(F, Asm, Layout);
- Asm.AddSectionToTheEnd(SymtabSD, Layout);
+ if (NeedsSymtabShndx) {
+ const MCSectionELF *SymtabShndxSection =
+ Ctx.getELFSection(".symtab_shndx", ELF::SHT_SYMTAB_SHNDX, 0,
+ SectionKind::getReadOnly(), 4, "");
+ SymtabShndxSD = &Asm.getOrCreateSectionData(*SymtabShndxSection);
+ SymtabShndxSD->setAlignment(4);
+ }
- const MCSection *StrtabSection;
+ const MCSectionELF *StrtabSection;
StrtabSection = Ctx.getELFSection(".strtab", ELF::SHT_STRTAB, 0,
- SectionKind::getReadOnly(), false);
-
+ SectionKind::getReadOnly());
MCSectionData &StrtabSD = Asm.getOrCreateSectionData(*StrtabSection);
StrtabSD.setAlignment(1);
- // FIXME: This isn't right. If the sections get rearranged this will
- // be wrong. We need a proper lookup.
- StringTableIndex = Asm.size();
+ ComputeIndexMap(Asm, SectionIndexMap, RelMap);
- F = new MCDataFragment(&StrtabSD);
- F->getContents().append(StringTable.begin(), StringTable.end());
- Asm.AddSectionToTheEnd(StrtabSD, Layout);
+ ShstrtabIndex = SectionIndexMap.lookup(ShstrtabSection);
+ SymbolTableIndex = SectionIndexMap.lookup(SymtabSection);
+ StringTableIndex = SectionIndexMap.lookup(StrtabSection);
- const MCSection *ShstrtabSection;
- ShstrtabSection = Ctx.getELFSection(".shstrtab", ELF::SHT_STRTAB, 0,
- SectionKind::getReadOnly(), false);
+ // Symbol table
+ F = new MCDataFragment(&SymtabSD);
+ MCDataFragment *ShndxF = NULL;
+ if (NeedsSymtabShndx) {
+ ShndxF = new MCDataFragment(SymtabShndxSD);
+ }
+ WriteSymbolTable(F, ShndxF, Asm, Layout, SectionIndexMap);
- MCSectionData &ShstrtabSD = Asm.getOrCreateSectionData(*ShstrtabSection);
- ShstrtabSD.setAlignment(1);
+ F = new MCDataFragment(&StrtabSD);
+ F->getContents().append(StringTable.begin(), StringTable.end());
F = new MCDataFragment(&ShstrtabSD);
- // FIXME: This isn't right. If the sections get rearranged this will
- // be wrong. We need a proper lookup.
- ShstrtabIndex = Asm.size();
+ std::vector<const MCSectionELF*> Sections;
+ for (MCAssembler::const_iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF&>(it->getSection());
+ Sections.push_back(&Section);
+ }
+ array_pod_sort(Sections.begin(), Sections.end(), compareBySuffix);
// Section header string table.
//
uint64_t Index = 1;
F->getContents() += '\x00';
- for (MCAssembler::const_iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it) {
- const MCSectionELF &Section =
- static_cast<const MCSectionELF&>(it->getSection());
+ for (unsigned int I = 0, E = Sections.size(); I != E; ++I) {
+ const MCSectionELF &Section = *Sections[I];
+ StringRef Name = Section.getSectionName();
+ if (I != 0) {
+ StringRef PreviousName = Sections[I - 1]->getSectionName();
+ if (PreviousName.endswith(Name)) {
+ SectionStringTableIndex[&Section] = Index - Name.size() - 1;
+ continue;
+ }
+ }
// Remember the index into the string table so we can write it
// into the sh_name field of the section header table.
- SectionStringTableIndex[&it->getSection()] = Index;
+ SectionStringTableIndex[&Section] = Index;
- Index += Section.getSectionName().size() + 1;
- F->getContents() += Section.getSectionName();
+ Index += Name.size() + 1;
+ F->getContents() += Name;
F->getContents() += '\x00';
}
+}
+
+void ELFObjectWriter::CreateIndexedSections(MCAssembler &Asm,
+ MCAsmLayout &Layout,
+ GroupMapTy &GroupMap,
+ RevGroupMapTy &RevGroupMap,
+ SectionIndexMapTy &SectionIndexMap,
+ const RelMapTy &RelMap) {
+ // Create the .note.GNU-stack section if needed.
+ MCContext &Ctx = Asm.getContext();
+ if (Asm.getNoExecStack()) {
+ const MCSectionELF *GnuStackSection =
+ Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS, 0,
+ SectionKind::getReadOnly());
+ Asm.getOrCreateSectionData(*GnuStackSection);
+ }
+
+ // Build the groups
+ for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
+ it != ie; ++it) {
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF&>(it->getSection());
+ if (!(Section.getFlags() & ELF::SHF_GROUP))
+ continue;
+
+ const MCSymbol *SignatureSymbol = Section.getGroup();
+ Asm.getOrCreateSymbolData(*SignatureSymbol);
+ const MCSectionELF *&Group = RevGroupMap[SignatureSymbol];
+ if (!Group) {
+ Group = Ctx.CreateELFGroupSection();
+ MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
+ Data.setAlignment(4);
+ MCDataFragment *F = new MCDataFragment(&Data);
+ String32(*F, ELF::GRP_COMDAT);
+ }
+ GroupMap[Group] = SignatureSymbol;
+ }
+
+ ComputeIndexMap(Asm, SectionIndexMap, RelMap);
- Asm.AddSectionToTheEnd(ShstrtabSD, Layout);
+ // Add sections to the groups
+ for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
+ it != ie; ++it) {
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF&>(it->getSection());
+ if (!(Section.getFlags() & ELF::SHF_GROUP))
+ continue;
+ const MCSectionELF *Group = RevGroupMap[Section.getGroup()];
+ MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
+ // FIXME: we could use the previous fragment
+ MCDataFragment *F = new MCDataFragment(&Data);
+ unsigned Index = SectionIndexMap.lookup(&Section);
+ String32(*F, Index);
+ }
}
-void ELFObjectWriterImpl::WriteObject(const MCAssembler &Asm,
- const MCAsmLayout &Layout) {
- // Compute symbol table information.
- ComputeSymbolTable(const_cast<MCAssembler&>(Asm));
+void ELFObjectWriter::WriteSection(MCAssembler &Asm,
+ const SectionIndexMapTy &SectionIndexMap,
+ uint32_t GroupSymbolIndex,
+ uint64_t Offset, uint64_t Size,
+ uint64_t Alignment,
+ const MCSectionELF &Section) {
+ uint64_t sh_link = 0;
+ uint64_t sh_info = 0;
+
+ switch(Section.getType()) {
+ case ELF::SHT_DYNAMIC:
+ sh_link = SectionStringTableIndex[&Section];
+ sh_info = 0;
+ break;
+
+ case ELF::SHT_REL:
+ case ELF::SHT_RELA: {
+ const MCSectionELF *SymtabSection;
+ const MCSectionELF *InfoSection;
+ SymtabSection = Asm.getContext().getELFSection(".symtab", ELF::SHT_SYMTAB,
+ 0,
+ SectionKind::getReadOnly());
+ sh_link = SectionIndexMap.lookup(SymtabSection);
+ assert(sh_link && ".symtab not found");
+
+ // Remove ".rel" and ".rela" prefixes.
+ unsigned SecNameLen = (Section.getType() == ELF::SHT_REL) ? 4 : 5;
+ StringRef SectionName = Section.getSectionName().substr(SecNameLen);
+
+ InfoSection = Asm.getContext().getELFSection(SectionName,
+ ELF::SHT_PROGBITS, 0,
+ SectionKind::getReadOnly());
+ sh_info = SectionIndexMap.lookup(InfoSection);
+ break;
+ }
- CreateMetadataSections(const_cast<MCAssembler&>(Asm),
- const_cast<MCAsmLayout&>(Layout));
+ case ELF::SHT_SYMTAB:
+ case ELF::SHT_DYNSYM:
+ sh_link = StringTableIndex;
+ 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_NOTE:
+ case ELF::SHT_NULL:
+ case ELF::SHT_ARM_ATTRIBUTES:
+ case ELF::SHT_INIT_ARRAY:
+ case ELF::SHT_FINI_ARRAY:
+ case ELF::SHT_PREINIT_ARRAY:
+ case ELF::SHT_X86_64_UNWIND:
+ // Nothing to do.
+ break;
+
+ case ELF::SHT_GROUP: {
+ sh_link = SymbolTableIndex;
+ sh_info = GroupSymbolIndex;
+ break;
+ }
- // Add 1 for the null section.
- unsigned NumSections = Asm.size() + 1;
+ default:
+ assert(0 && "FIXME: sh_type value not supported!");
+ break;
+ }
- uint64_t SectionDataSize = 0;
+ WriteSecHdrEntry(SectionStringTableIndex[&Section], Section.getType(),
+ Section.getFlags(), 0, Offset, Size, sh_link, sh_info,
+ Alignment, Section.getEntrySize());
+}
- for (MCAssembler::const_iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it) {
- const MCSectionData &SD = *it;
+bool ELFObjectWriter::IsELFMetaDataSection(const MCSectionData &SD) {
+ return SD.getOrdinal() == ~UINT32_C(0) &&
+ !SD.getSection().isVirtualSection();
+}
- // Get the size of the section in the output file (including padding).
- uint64_t Size = Layout.getSectionFileSize(&SD);
- SectionDataSize += Size;
+uint64_t ELFObjectWriter::DataSectionSize(const MCSectionData &SD) {
+ uint64_t Ret = 0;
+ for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e;
+ ++i) {
+ const MCFragment &F = *i;
+ assert(F.getKind() == MCFragment::FT_Data);
+ Ret += cast<MCDataFragment>(F).getContents().size();
}
+ return Ret;
+}
- // Write out the ELF header ...
- WriteHeader(SectionDataSize, NumSections);
- FileOff = Is64Bit ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr);
+uint64_t ELFObjectWriter::GetSectionFileSize(const MCAsmLayout &Layout,
+ const MCSectionData &SD) {
+ if (IsELFMetaDataSection(SD))
+ return DataSectionSize(SD);
+ return Layout.getSectionFileSize(&SD);
+}
- // ... then all of the sections ...
- DenseMap<const MCSection*, uint64_t> SectionOffsetMap;
+uint64_t ELFObjectWriter::GetSectionAddressSize(const MCAsmLayout &Layout,
+ const MCSectionData &SD) {
+ if (IsELFMetaDataSection(SD))
+ return DataSectionSize(SD);
+ return Layout.getSectionAddressSize(&SD);
+}
- for (MCAssembler::const_iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it) {
- // Remember the offset into the file for this section.
- SectionOffsetMap[&it->getSection()] = FileOff;
+void ELFObjectWriter::WriteDataSectionData(MCAssembler &Asm,
+ const MCAsmLayout &Layout,
+ const MCSectionELF &Section) {
+ uint64_t FileOff = OS.tell();
+ const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
+
+ uint64_t Padding = OffsetToAlignment(FileOff, SD.getAlignment());
+ WriteZeros(Padding);
+ FileOff += Padding;
+
+ FileOff += GetSectionFileSize(Layout, SD);
+
+ if (IsELFMetaDataSection(SD)) {
+ for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e;
+ ++i) {
+ const MCFragment &F = *i;
+ assert(F.getKind() == MCFragment::FT_Data);
+ WriteBytes(cast<MCDataFragment>(F).getContents().str());
+ }
+ } else {
+ Asm.WriteSectionData(&SD, Layout);
+ }
+}
- const MCSectionData &SD = *it;
- FileOff += Layout.getSectionFileSize(&SD);
+void ELFObjectWriter::WriteSectionHeader(MCAssembler &Asm,
+ const GroupMapTy &GroupMap,
+ const MCAsmLayout &Layout,
+ const SectionIndexMapTy &SectionIndexMap,
+ const SectionOffsetMapTy &SectionOffsetMap) {
+ const unsigned NumSections = Asm.size() + 1;
+
+ std::vector<const MCSectionELF*> Sections;
+ Sections.resize(NumSections - 1);
- Asm.WriteSectionData(it, Layout, Writer);
+ for (SectionIndexMapTy::const_iterator i=
+ SectionIndexMap.begin(), e = SectionIndexMap.end(); i != e; ++i) {
+ const std::pair<const MCSectionELF*, uint32_t> &p = *i;
+ Sections[p.second - 1] = p.first;
}
- // ... and then the section header table.
- // 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 (unsigned i = 0; i < NumSections - 1; ++i) {
+ const MCSectionELF &Section = *Sections[i];
+ const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
+ uint32_t GroupSymbolIndex;
+ if (Section.getType() != ELF::SHT_GROUP)
+ GroupSymbolIndex = 0;
+ else
+ GroupSymbolIndex = getSymbolIndexInSymbolTable(Asm,
+ GroupMap.lookup(&Section));
- for (MCAssembler::const_iterator it = Asm.begin(),
+ uint64_t Size = GetSectionAddressSize(Layout, SD);
+
+ WriteSection(Asm, SectionIndexMap, GroupSymbolIndex,
+ SectionOffsetMap.lookup(&Section), Size,
+ SD.getAlignment(), Section);
+ }
+}
+
+void ELFObjectWriter::ComputeSectionOrder(MCAssembler &Asm,
+ std::vector<const MCSectionELF*> &Sections) {
+ for (MCAssembler::iterator it = Asm.begin(),
ie = Asm.end(); it != ie; ++it) {
- const MCSectionData &SD = *it;
const MCSectionELF &Section =
- static_cast<const MCSectionELF&>(SD.getSection());
+ static_cast<const MCSectionELF &>(it->getSection());
+ if (Section.getType() == ELF::SHT_GROUP)
+ Sections.push_back(&Section);
+ }
- uint64_t sh_link = 0;
- uint64_t sh_info = 0;
+ for (MCAssembler::iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF &>(it->getSection());
+ if (Section.getType() != ELF::SHT_GROUP &&
+ Section.getType() != ELF::SHT_REL &&
+ Section.getType() != ELF::SHT_RELA)
+ Sections.push_back(&Section);
+ }
- switch(Section.getType()) {
- case ELF::SHT_DYNAMIC:
- sh_link = SectionStringTableIndex[&it->getSection()];
- sh_info = 0;
- break;
+ for (MCAssembler::iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF &>(it->getSection());
+ if (Section.getType() == ELF::SHT_REL ||
+ Section.getType() == ELF::SHT_RELA)
+ Sections.push_back(&Section);
+ }
+}
- case ELF::SHT_REL:
- case ELF::SHT_RELA: {
- const MCSection *SymtabSection;
- const MCSection *InfoSection;
- const MCSectionData *SymtabSD;
- const MCSectionData *InfoSD;
-
- SymtabSection = Asm.getContext().getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
- SectionKind::getReadOnly(),
- false);
- SymtabSD = &Asm.getSectionData(*SymtabSection);
- // we have to count the empty section in too
- sh_link = SymtabSD->getLayoutOrder() + 1;
-
- // Remove ".rel" and ".rela" prefixes.
- unsigned SecNameLen = (Section.getType() == ELF::SHT_REL) ? 4 : 5;
- StringRef SectionName = Section.getSectionName().substr(SecNameLen);
-
- InfoSection = Asm.getContext().getELFSection(SectionName,
- ELF::SHT_PROGBITS, 0,
- SectionKind::getReadOnly(),
- false);
- InfoSD = &Asm.getSectionData(*InfoSection);
- sh_info = InfoSD->getLayoutOrder() + 1;
- break;
- }
+void ELFObjectWriter::WriteObject(MCAssembler &Asm,
+ const MCAsmLayout &Layout) {
+ GroupMapTy GroupMap;
+ RevGroupMapTy RevGroupMap;
+ SectionIndexMapTy SectionIndexMap;
- case ELF::SHT_SYMTAB:
- case ELF::SHT_DYNSYM:
- sh_link = StringTableIndex;
- sh_info = LastLocalSymbolIndex;
- break;
+ unsigned NumUserSections = Asm.size();
- case ELF::SHT_PROGBITS:
- case ELF::SHT_STRTAB:
- case ELF::SHT_NOBITS:
- // Nothing to do.
- break;
+ DenseMap<const MCSectionELF*, const MCSectionELF*> RelMap;
+ CreateRelocationSections(Asm, const_cast<MCAsmLayout&>(Layout), RelMap);
+
+ const unsigned NumUserAndRelocSections = Asm.size();
+ CreateIndexedSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap,
+ RevGroupMap, SectionIndexMap, RelMap);
+ const unsigned AllSections = Asm.size();
+ const unsigned NumIndexedSections = AllSections - NumUserAndRelocSections;
+
+ unsigned NumRegularSections = NumUserSections + NumIndexedSections;
+
+ // Compute symbol table information.
+ ComputeSymbolTable(Asm, SectionIndexMap, RevGroupMap, NumRegularSections);
+
+
+ WriteRelocations(Asm, const_cast<MCAsmLayout&>(Layout), RelMap);
- case ELF::SHT_HASH:
- case ELF::SHT_GROUP:
- case ELF::SHT_SYMTAB_SHNDX:
+ CreateMetadataSections(const_cast<MCAssembler&>(Asm),
+ const_cast<MCAsmLayout&>(Layout),
+ SectionIndexMap,
+ RelMap);
+
+ uint64_t NaturalAlignment = is64Bit() ? 8 : 4;
+ uint64_t HeaderSize = is64Bit() ? sizeof(ELF::Elf64_Ehdr) :
+ sizeof(ELF::Elf32_Ehdr);
+ uint64_t FileOff = HeaderSize;
+
+ std::vector<const MCSectionELF*> Sections;
+ ComputeSectionOrder(Asm, Sections);
+ unsigned NumSections = Sections.size();
+ SectionOffsetMapTy SectionOffsetMap;
+ for (unsigned i = 0; i < NumRegularSections + 1; ++i) {
+ const MCSectionELF &Section = *Sections[i];
+ const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
+
+ FileOff = RoundUpToAlignment(FileOff, SD.getAlignment());
+
+ // Remember the offset into the file for this section.
+ SectionOffsetMap[&Section] = FileOff;
+
+ // Get the size of the section in the output file (including padding).
+ FileOff += GetSectionFileSize(Layout, SD);
+ }
+
+ FileOff = RoundUpToAlignment(FileOff, NaturalAlignment);
+
+ const unsigned SectionHeaderOffset = FileOff - HeaderSize;
+
+ uint64_t SectionHeaderEntrySize = is64Bit() ?
+ sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr);
+ FileOff += (NumSections + 1) * SectionHeaderEntrySize;
+
+ for (unsigned i = NumRegularSections + 1; i < NumSections; ++i) {
+ const MCSectionELF &Section = *Sections[i];
+ const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
+
+ FileOff = RoundUpToAlignment(FileOff, SD.getAlignment());
+
+ // Remember the offset into the file for this section.
+ SectionOffsetMap[&Section] = FileOff;
+
+ // Get the size of the section in the output file (including padding).
+ FileOff += GetSectionFileSize(Layout, SD);
+ }
+
+ // Write out the ELF header ...
+ WriteHeader(SectionHeaderOffset, NumSections + 1);
+
+ // ... then the regular sections ...
+ // + because of .shstrtab
+ for (unsigned i = 0; i < NumRegularSections + 1; ++i)
+ WriteDataSectionData(Asm, Layout, *Sections[i]);
+
+ FileOff = OS.tell();
+ uint64_t Padding = OffsetToAlignment(FileOff, NaturalAlignment);
+ WriteZeros(Padding);
+
+ // ... then the section header table ...
+ WriteSectionHeader(Asm, GroupMap, Layout, SectionIndexMap,
+ SectionOffsetMap);
+
+ FileOff = OS.tell();
+
+ // ... and then the remainting sections ...
+ for (unsigned i = NumRegularSections + 1; i < NumSections; ++i)
+ WriteDataSectionData(Asm, Layout, *Sections[i]);
+}
+
+bool
+ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
+ const MCSymbolData &DataA,
+ const MCFragment &FB,
+ bool InSet,
+ bool IsPCRel) const {
+ if (DataA.getFlags() & ELF_STB_Weak)
+ return false;
+ return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
+ Asm, DataA, FB,InSet, IsPCRel);
+}
+
+MCObjectWriter *llvm::createELFObjectWriter(MCELFObjectTargetWriter *MOTW,
+ raw_ostream &OS,
+ bool IsLittleEndian) {
+ switch (MOTW->getEMachine()) {
+ case ELF::EM_386:
+ case ELF::EM_X86_64:
+ return new X86ELFObjectWriter(MOTW, OS, IsLittleEndian); break;
+ case ELF::EM_ARM:
+ return new ARMELFObjectWriter(MOTW, OS, IsLittleEndian); break;
+ case ELF::EM_MBLAZE:
+ return new MBlazeELFObjectWriter(MOTW, OS, IsLittleEndian); break;
+ default: llvm_unreachable("Unsupported architecture"); break;
+ }
+}
+
+
+/// START OF SUBCLASSES for ELFObjectWriter
+//===- ARMELFObjectWriter -------------------------------------------===//
+
+ARMELFObjectWriter::ARMELFObjectWriter(MCELFObjectTargetWriter *MOTW,
+ raw_ostream &_OS,
+ bool IsLittleEndian)
+ : ELFObjectWriter(MOTW, _OS, IsLittleEndian)
+{}
+
+ARMELFObjectWriter::~ARMELFObjectWriter()
+{}
+
+// FIXME: get the real EABI Version from the Triple.
+void ARMELFObjectWriter::WriteEFlags() {
+ Write32(ELF::EF_ARM_EABIMASK & DefaultEABIVersion);
+}
+
+// In ARM, _MergedGlobals and other most symbols get emitted directly.
+// I.e. not as an offset to a section symbol.
+// This code is an approximation of what ARM/gcc does.
+
+STATISTIC(PCRelCount, "Total number of PIC Relocations");
+STATISTIC(NonPCRelCount, "Total number of non-PIC relocations");
+
+const MCSymbol *ARMELFObjectWriter::ExplicitRelSym(const MCAssembler &Asm,
+ const MCValue &Target,
+ const MCFragment &F,
+ const MCFixup &Fixup,
+ bool IsPCRel) const {
+ const MCSymbol &Symbol = Target.getSymA()->getSymbol();
+ bool EmitThisSym = false;
+
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF&>(Symbol.getSection());
+ bool InNormalSection = true;
+ unsigned RelocType = 0;
+ RelocType = GetRelocTypeInner(Target, Fixup, IsPCRel);
+
+ DEBUG(
+ const MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind();
+ MCSymbolRefExpr::VariantKind Kind2;
+ Kind2 = Target.getSymB() ? Target.getSymB()->getKind() :
+ MCSymbolRefExpr::VK_None;
+ dbgs() << "considering symbol "
+ << Section.getSectionName() << "/"
+ << Symbol.getName() << "/"
+ << " Rel:" << (unsigned)RelocType
+ << " Kind: " << (int)Kind << "/" << (int)Kind2
+ << " Tmp:"
+ << Symbol.isAbsolute() << "/" << Symbol.isDefined() << "/"
+ << Symbol.isVariable() << "/" << Symbol.isTemporary()
+ << " Counts:" << PCRelCount << "/" << NonPCRelCount << "\n");
+
+ if (IsPCRel) { ++PCRelCount;
+ switch (RelocType) {
default:
- assert(0 && "FIXME: sh_type value not supported!");
+ // Most relocation types are emitted as explicit symbols
+ InNormalSection =
+ StringSwitch<bool>(Section.getSectionName())
+ .Case(".data.rel.ro.local", false)
+ .Case(".data.rel", false)
+ .Case(".bss", false)
+ .Default(true);
+ EmitThisSym = true;
break;
+ case ELF::R_ARM_ABS32:
+ // But things get strange with R_ARM_ABS32
+ // In this case, most things that go in .rodata show up
+ // as section relative relocations
+ InNormalSection =
+ StringSwitch<bool>(Section.getSectionName())
+ .Case(".data.rel.ro.local", false)
+ .Case(".data.rel", false)
+ .Case(".rodata", false)
+ .Case(".bss", false)
+ .Default(true);
+ EmitThisSym = false;
+ break;
+ }
+ } else {
+ NonPCRelCount++;
+ InNormalSection =
+ StringSwitch<bool>(Section.getSectionName())
+ .Case(".data.rel.ro.local", false)
+ .Case(".rodata", false)
+ .Case(".data.rel", false)
+ .Case(".bss", false)
+ .Default(true);
+
+ switch (RelocType) {
+ default: EmitThisSym = true; break;
+ case ELF::R_ARM_ABS32: EmitThisSym = false; break;
}
+ }
- WriteSecHdrEntry(SectionStringTableIndex[&it->getSection()],
- Section.getType(), Section.getFlags(),
- Layout.getSectionAddress(&SD),
- SectionOffsetMap.lookup(&SD.getSection()),
- Layout.getSectionSize(&SD), sh_link,
- sh_info, SD.getAlignment(),
- Section.getEntrySize());
+ if (EmitThisSym)
+ return &Symbol;
+ if (! Symbol.isTemporary() && InNormalSection) {
+ return &Symbol;
}
+ return NULL;
}
-ELFObjectWriter::ELFObjectWriter(raw_ostream &OS,
- bool Is64Bit,
- bool IsLittleEndian,
- bool HasRelocationAddend)
- : MCObjectWriter(OS, IsLittleEndian)
-{
- Impl = new ELFObjectWriterImpl(this, Is64Bit, HasRelocationAddend);
+// Need to examine the Fixup when determining whether to
+// emit the relocation as an explicit symbol or as a section relative
+// offset
+unsigned ARMELFObjectWriter::GetRelocType(const MCValue &Target,
+ const MCFixup &Fixup,
+ bool IsPCRel,
+ bool IsRelocWithSymbol,
+ int64_t Addend) {
+ MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
+ MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
+
+ unsigned Type = GetRelocTypeInner(Target, Fixup, IsPCRel);
+
+ if (RelocNeedsGOT(Modifier))
+ NeedsGOT = true;
+
+ return Type;
+}
+
+unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
+ const MCFixup &Fixup,
+ bool IsPCRel) const {
+ MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
+ MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
+
+ unsigned Type = 0;
+ if (IsPCRel) {
+ switch ((unsigned)Fixup.getKind()) {
+ default: assert(0 && "Unimplemented");
+ case FK_Data_4:
+ switch (Modifier) {
+ default: llvm_unreachable("Unsupported Modifier");
+ case MCSymbolRefExpr::VK_None:
+ Type = ELF::R_ARM_REL32;
+ break;
+ case MCSymbolRefExpr::VK_ARM_TLSGD:
+ assert(0 && "unimplemented");
+ break;
+ case MCSymbolRefExpr::VK_ARM_GOTTPOFF:
+ Type = ELF::R_ARM_TLS_IE32;
+ break;
+ }
+ break;
+ case ARM::fixup_arm_uncondbranch:
+ switch (Modifier) {
+ case MCSymbolRefExpr::VK_ARM_PLT:
+ Type = ELF::R_ARM_PLT32;
+ break;
+ default:
+ Type = ELF::R_ARM_CALL;
+ break;
+ }
+ break;
+ case ARM::fixup_arm_condbranch:
+ Type = ELF::R_ARM_JUMP24;
+ break;
+ case ARM::fixup_arm_movt_hi16:
+ case ARM::fixup_arm_movt_hi16_pcrel:
+ Type = ELF::R_ARM_MOVT_PREL;
+ break;
+ case ARM::fixup_arm_movw_lo16:
+ case ARM::fixup_arm_movw_lo16_pcrel:
+ Type = ELF::R_ARM_MOVW_PREL_NC;
+ break;
+ case ARM::fixup_t2_movt_hi16:
+ case ARM::fixup_t2_movt_hi16_pcrel:
+ Type = ELF::R_ARM_THM_MOVT_PREL;
+ break;
+ case ARM::fixup_t2_movw_lo16:
+ case ARM::fixup_t2_movw_lo16_pcrel:
+ Type = ELF::R_ARM_THM_MOVW_PREL_NC;
+ break;
+ case ARM::fixup_arm_thumb_bl:
+ case ARM::fixup_arm_thumb_blx:
+ switch (Modifier) {
+ case MCSymbolRefExpr::VK_ARM_PLT:
+ Type = ELF::R_ARM_THM_CALL;
+ break;
+ default:
+ Type = ELF::R_ARM_NONE;
+ break;
+ }
+ break;
+ }
+ } else {
+ switch ((unsigned)Fixup.getKind()) {
+ default: llvm_unreachable("invalid fixup kind!");
+ case FK_Data_4:
+ switch (Modifier) {
+ default: llvm_unreachable("Unsupported Modifier"); break;
+ case MCSymbolRefExpr::VK_ARM_GOT:
+ Type = ELF::R_ARM_GOT_BREL;
+ break;
+ case MCSymbolRefExpr::VK_ARM_TLSGD:
+ Type = ELF::R_ARM_TLS_GD32;
+ break;
+ case MCSymbolRefExpr::VK_ARM_TPOFF:
+ Type = ELF::R_ARM_TLS_LE32;
+ break;
+ case MCSymbolRefExpr::VK_ARM_GOTTPOFF:
+ Type = ELF::R_ARM_TLS_IE32;
+ break;
+ case MCSymbolRefExpr::VK_None:
+ Type = ELF::R_ARM_ABS32;
+ break;
+ case MCSymbolRefExpr::VK_ARM_GOTOFF:
+ Type = ELF::R_ARM_GOTOFF32;
+ break;
+ }
+ break;
+ case ARM::fixup_arm_ldst_pcrel_12:
+ case ARM::fixup_arm_pcrel_10:
+ case ARM::fixup_arm_adr_pcrel_12:
+ case ARM::fixup_arm_thumb_bl:
+ case ARM::fixup_arm_thumb_cb:
+ case ARM::fixup_arm_thumb_cp:
+ case ARM::fixup_arm_thumb_br:
+ assert(0 && "Unimplemented");
+ break;
+ case ARM::fixup_arm_uncondbranch:
+ Type = ELF::R_ARM_CALL;
+ break;
+ case ARM::fixup_arm_condbranch:
+ Type = ELF::R_ARM_JUMP24;
+ break;
+ case ARM::fixup_arm_movt_hi16:
+ Type = ELF::R_ARM_MOVT_ABS;
+ break;
+ case ARM::fixup_arm_movw_lo16:
+ Type = ELF::R_ARM_MOVW_ABS_NC;
+ break;
+ case ARM::fixup_t2_movt_hi16:
+ Type = ELF::R_ARM_THM_MOVT_ABS;
+ break;
+ case ARM::fixup_t2_movw_lo16:
+ Type = ELF::R_ARM_THM_MOVW_ABS_NC;
+ break;
+ }
+ }
+
+ return Type;
}
-ELFObjectWriter::~ELFObjectWriter() {
- delete (ELFObjectWriterImpl*) Impl;
+//===- MBlazeELFObjectWriter -------------------------------------------===//
+
+MBlazeELFObjectWriter::MBlazeELFObjectWriter(MCELFObjectTargetWriter *MOTW,
+ raw_ostream &_OS,
+ bool IsLittleEndian)
+ : ELFObjectWriter(MOTW, _OS, IsLittleEndian) {
}
-void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm) {
- ((ELFObjectWriterImpl*) Impl)->ExecutePostLayoutBinding(Asm);
+MBlazeELFObjectWriter::~MBlazeELFObjectWriter() {
}
-void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
- const MCAsmLayout &Layout,
- const MCFragment *Fragment,
- const MCFixup &Fixup, MCValue Target,
- uint64_t &FixedValue) {
- ((ELFObjectWriterImpl*) Impl)->RecordRelocation(Asm, Layout, Fragment, Fixup,
- Target, FixedValue);
+unsigned MBlazeELFObjectWriter::GetRelocType(const MCValue &Target,
+ const MCFixup &Fixup,
+ bool IsPCRel,
+ bool IsRelocWithSymbol,
+ int64_t Addend) {
+ // determine the type of the relocation
+ unsigned Type;
+ if (IsPCRel) {
+ switch ((unsigned)Fixup.getKind()) {
+ default:
+ llvm_unreachable("Unimplemented");
+ case FK_PCRel_4:
+ Type = ELF::R_MICROBLAZE_64_PCREL;
+ break;
+ case FK_PCRel_2:
+ Type = ELF::R_MICROBLAZE_32_PCREL;
+ break;
+ }
+ } else {
+ switch ((unsigned)Fixup.getKind()) {
+ default: llvm_unreachable("invalid fixup kind!");
+ case FK_Data_4:
+ Type = ((IsRelocWithSymbol || Addend !=0)
+ ? ELF::R_MICROBLAZE_32
+ : ELF::R_MICROBLAZE_64);
+ break;
+ case FK_Data_2:
+ Type = ELF::R_MICROBLAZE_32;
+ break;
+ }
+ }
+ return Type;
}
-void ELFObjectWriter::WriteObject(const MCAssembler &Asm,
- const MCAsmLayout &Layout) {
- ((ELFObjectWriterImpl*) Impl)->WriteObject(Asm, Layout);
+//===- X86ELFObjectWriter -------------------------------------------===//
+
+
+X86ELFObjectWriter::X86ELFObjectWriter(MCELFObjectTargetWriter *MOTW,
+ raw_ostream &_OS,
+ bool IsLittleEndian)
+ : ELFObjectWriter(MOTW, _OS, IsLittleEndian)
+{}
+
+X86ELFObjectWriter::~X86ELFObjectWriter()
+{}
+
+unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
+ const MCFixup &Fixup,
+ bool IsPCRel,
+ bool IsRelocWithSymbol,
+ int64_t Addend) {
+ // determine the type of the relocation
+
+ MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
+ MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
+ unsigned Type;
+ if (is64Bit()) {
+ if (IsPCRel) {
+ switch ((unsigned)Fixup.getKind()) {
+ default: llvm_unreachable("invalid fixup kind!");
+
+ case FK_Data_8: Type = ELF::R_X86_64_PC64; break;
+ case FK_Data_4: Type = ELF::R_X86_64_PC32; break;
+ case FK_Data_2: Type = ELF::R_X86_64_PC16; break;
+
+ case FK_PCRel_8:
+ assert(Modifier == MCSymbolRefExpr::VK_None);
+ Type = ELF::R_X86_64_PC64;
+ break;
+ case X86::reloc_signed_4byte:
+ case X86::reloc_riprel_4byte_movq_load:
+ case X86::reloc_riprel_4byte:
+ case FK_PCRel_4:
+ 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;
+ }
+ break;
+ case FK_PCRel_2:
+ assert(Modifier == MCSymbolRefExpr::VK_None);
+ Type = ELF::R_X86_64_PC16;
+ break;
+ case FK_PCRel_1:
+ assert(Modifier == MCSymbolRefExpr::VK_None);
+ Type = ELF::R_X86_64_PC8;
+ break;
+ }
+ } else {
+ switch ((unsigned)Fixup.getKind()) {
+ default: llvm_unreachable("invalid fixup kind!");
+ case FK_Data_8: Type = ELF::R_X86_64_64; break;
+ case X86::reloc_signed_4byte:
+ assert(isInt<32>(Target.getConstant()));
+ 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;
+ break;
+ case FK_Data_2: Type = ELF::R_X86_64_16; break;
+ case FK_PCRel_1:
+ case FK_Data_1: Type = ELF::R_X86_64_8; break;
+ }
+ }
+ } else {
+ if (IsPCRel) {
+ 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 FK_PCRel_4:
+ 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;
+ case MCSymbolRefExpr::VK_GOTTPOFF:
+ Type = ELF::R_386_TLS_IE_32;
+ break;
+ }
+ break;
+ case FK_Data_2: Type = ELF::R_386_16; break;
+ case FK_PCRel_1:
+ case FK_Data_1: Type = ELF::R_386_8; break;
+ }
+ }
+ }
+
+ if (RelocNeedsGOT(Modifier))
+ NeedsGOT = true;
+
+ return Type;
}