1 //===- lib/MC/ELFObjectWriter.cpp - ELF File Writer -------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements ELF object file writer information.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/ADT/SmallPtrSet.h"
15 #include "llvm/ADT/STLExtras.h"
16 #include "llvm/ADT/StringMap.h"
17 #include "llvm/ADT/Twine.h"
18 #include "llvm/MC/MCAssembler.h"
19 #include "llvm/MC/MCAsmLayout.h"
20 #include "llvm/MC/MCContext.h"
21 #include "llvm/MC/MCELFSymbolFlags.h"
22 #include "llvm/MC/MCExpr.h"
23 #include "llvm/MC/MCObjectWriter.h"
24 #include "llvm/MC/MCSectionELF.h"
25 #include "llvm/MC/MCSymbol.h"
26 #include "llvm/MC/MCValue.h"
27 #include "llvm/Support/Debug.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/ELF.h"
30 #include "llvm/Target/TargetAsmBackend.h"
32 #include "../Target/X86/X86FixupKinds.h"
33 #include "../Target/ARM/ARMFixupKinds.h"
38 static unsigned GetType(const MCSymbolData &SD) {
39 uint32_t Type = (SD.getFlags() & (0xf << ELF_STT_Shift)) >> ELF_STT_Shift;
40 assert(Type == ELF::STT_NOTYPE || Type == ELF::STT_OBJECT ||
41 Type == ELF::STT_FUNC || Type == ELF::STT_SECTION ||
42 Type == ELF::STT_FILE || Type == ELF::STT_COMMON ||
43 Type == ELF::STT_TLS);
47 static unsigned GetBinding(const MCSymbolData &SD) {
48 uint32_t Binding = (SD.getFlags() & (0xf << ELF_STB_Shift)) >> ELF_STB_Shift;
49 assert(Binding == ELF::STB_LOCAL || Binding == ELF::STB_GLOBAL ||
50 Binding == ELF::STB_WEAK);
54 static void SetBinding(MCSymbolData &SD, unsigned Binding) {
55 assert(Binding == ELF::STB_LOCAL || Binding == ELF::STB_GLOBAL ||
56 Binding == ELF::STB_WEAK);
57 uint32_t OtherFlags = SD.getFlags() & ~(0xf << ELF_STB_Shift);
58 SD.setFlags(OtherFlags | (Binding << ELF_STB_Shift));
61 static unsigned GetVisibility(MCSymbolData &SD) {
63 (SD.getFlags() & (0xf << ELF_STV_Shift)) >> ELF_STV_Shift;
64 assert(Visibility == ELF::STV_DEFAULT || Visibility == ELF::STV_INTERNAL ||
65 Visibility == ELF::STV_HIDDEN || Visibility == ELF::STV_PROTECTED);
70 static bool RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant) {
74 case MCSymbolRefExpr::VK_GOT:
75 case MCSymbolRefExpr::VK_PLT:
76 case MCSymbolRefExpr::VK_GOTPCREL:
77 case MCSymbolRefExpr::VK_TPOFF:
78 case MCSymbolRefExpr::VK_TLSGD:
79 case MCSymbolRefExpr::VK_GOTTPOFF:
80 case MCSymbolRefExpr::VK_INDNTPOFF:
81 case MCSymbolRefExpr::VK_NTPOFF:
82 case MCSymbolRefExpr::VK_GOTNTPOFF:
83 case MCSymbolRefExpr::VK_TLSLDM:
84 case MCSymbolRefExpr::VK_DTPOFF:
85 case MCSymbolRefExpr::VK_TLSLD:
91 class ELFObjectWriter : public MCObjectWriter {
93 /*static bool isFixupKindX86RIPRel(unsigned Kind) {
94 return Kind == X86::reloc_riprel_4byte ||
95 Kind == X86::reloc_riprel_4byte_movq_load;
99 /// ELFSymbolData - Helper struct for containing some precomputed information
101 struct ELFSymbolData {
102 MCSymbolData *SymbolData;
103 uint64_t StringIndex;
104 uint32_t SectionIndex;
106 // Support lexicographic sorting.
107 bool operator<(const ELFSymbolData &RHS) const {
108 if (GetType(*SymbolData) == ELF::STT_FILE)
110 if (GetType(*RHS.SymbolData) == ELF::STT_FILE)
112 return SymbolData->getSymbol().getName() <
113 RHS.SymbolData->getSymbol().getName();
117 /// @name Relocation Data
120 struct ELFRelocationEntry {
121 // Make these big enough for both 32-bit and 64-bit
125 const MCSymbol *Symbol;
129 : r_offset(0), Index(0), Type(0), Symbol(0), r_addend(0) {}
131 ELFRelocationEntry(uint64_t RelocOffset, int Idx,
132 unsigned RelType, const MCSymbol *Sym,
134 : r_offset(RelocOffset), Index(Idx), Type(RelType),
135 Symbol(Sym), r_addend(Addend) {}
137 // Support lexicographic sorting.
138 bool operator<(const ELFRelocationEntry &RE) const {
139 return RE.r_offset < r_offset;
143 SmallPtrSet<const MCSymbol *, 16> UsedInReloc;
144 SmallPtrSet<const MCSymbol *, 16> WeakrefUsedInReloc;
145 DenseMap<const MCSymbol *, const MCSymbol *> Renames;
147 llvm::DenseMap<const MCSectionData*,
148 std::vector<ELFRelocationEntry> > Relocations;
149 DenseMap<const MCSection*, uint64_t> SectionStringTableIndex;
152 /// @name Symbol Table Data
155 SmallString<256> StringTable;
156 std::vector<ELFSymbolData> LocalSymbolData;
157 std::vector<ELFSymbolData> ExternalSymbolData;
158 std::vector<ELFSymbolData> UndefinedSymbolData;
164 bool NeedsSymtabShndx;
166 unsigned Is64Bit : 1;
168 bool HasRelocationAddend;
170 Triple::OSType OSType;
174 // This holds the symbol table index of the last local symbol.
175 unsigned LastLocalSymbolIndex;
176 // This holds the .strtab section index.
177 unsigned StringTableIndex;
178 // This holds the .symtab section index.
179 unsigned SymbolTableIndex;
181 unsigned ShstrtabIndex;
184 const MCSymbol *SymbolToReloc(const MCAssembler &Asm,
185 const MCValue &Target,
186 const MCFragment &F) const;
189 ELFObjectWriter(raw_ostream &_OS, bool _Is64Bit, bool IsLittleEndian,
190 uint16_t _EMachine, bool _HasRelAddend,
191 Triple::OSType _OSType)
192 : MCObjectWriter(_OS, IsLittleEndian),
193 NeedsGOT(false), NeedsSymtabShndx(false),
194 Is64Bit(_Is64Bit), HasRelocationAddend(_HasRelAddend),
195 OSType(_OSType), EMachine(_EMachine) {
198 virtual ~ELFObjectWriter();
200 void WriteWord(uint64_t W) {
207 void StringLE16(char *buf, uint16_t Value) {
208 buf[0] = char(Value >> 0);
209 buf[1] = char(Value >> 8);
212 void StringLE32(char *buf, uint32_t Value) {
213 StringLE16(buf, uint16_t(Value >> 0));
214 StringLE16(buf + 2, uint16_t(Value >> 16));
217 void StringLE64(char *buf, uint64_t Value) {
218 StringLE32(buf, uint32_t(Value >> 0));
219 StringLE32(buf + 4, uint32_t(Value >> 32));
222 void StringBE16(char *buf ,uint16_t Value) {
223 buf[0] = char(Value >> 8);
224 buf[1] = char(Value >> 0);
227 void StringBE32(char *buf, uint32_t Value) {
228 StringBE16(buf, uint16_t(Value >> 16));
229 StringBE16(buf + 2, uint16_t(Value >> 0));
232 void StringBE64(char *buf, uint64_t Value) {
233 StringBE32(buf, uint32_t(Value >> 32));
234 StringBE32(buf + 4, uint32_t(Value >> 0));
237 void String8(MCDataFragment &F, uint8_t Value) {
240 F.getContents() += StringRef(buf, 1);
243 void String16(MCDataFragment &F, uint16_t Value) {
245 if (isLittleEndian())
246 StringLE16(buf, Value);
248 StringBE16(buf, Value);
249 F.getContents() += StringRef(buf, 2);
252 void String32(MCDataFragment &F, uint32_t Value) {
254 if (isLittleEndian())
255 StringLE32(buf, Value);
257 StringBE32(buf, Value);
258 F.getContents() += StringRef(buf, 4);
261 void String64(MCDataFragment &F, uint64_t Value) {
263 if (isLittleEndian())
264 StringLE64(buf, Value);
266 StringBE64(buf, Value);
267 F.getContents() += StringRef(buf, 8);
270 virtual void WriteHeader(uint64_t SectionDataSize, unsigned NumberOfSections);
272 virtual void WriteSymbolEntry(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
273 uint64_t name, uint8_t info,
274 uint64_t value, uint64_t size,
275 uint8_t other, uint32_t shndx,
278 virtual void WriteSymbol(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
280 const MCAsmLayout &Layout);
282 typedef DenseMap<const MCSectionELF*, uint32_t> SectionIndexMapTy;
283 virtual void WriteSymbolTable(MCDataFragment *SymtabF, MCDataFragment *ShndxF,
284 const MCAssembler &Asm,
285 const MCAsmLayout &Layout,
286 const SectionIndexMapTy &SectionIndexMap);
288 virtual void RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
289 const MCFragment *Fragment, const MCFixup &Fixup,
290 MCValue Target, uint64_t &FixedValue) {
291 assert(0 && "RecordRelocation is not specific enough");
294 virtual uint64_t getSymbolIndexInSymbolTable(const MCAssembler &Asm,
297 // Map from a group section to the signature symbol
298 typedef DenseMap<const MCSectionELF*, const MCSymbol*> GroupMapTy;
299 // Map from a signature symbol to the group section
300 typedef DenseMap<const MCSymbol*, const MCSectionELF*> RevGroupMapTy;
302 /// ComputeSymbolTable - Compute the symbol table data
304 /// \param StringTable [out] - The string table data.
305 /// \param StringIndexMap [out] - Map from symbol names to offsets in the
307 virtual void ComputeSymbolTable(MCAssembler &Asm,
308 const SectionIndexMapTy &SectionIndexMap,
309 RevGroupMapTy RevGroupMap);
311 virtual void ComputeIndexMap(MCAssembler &Asm,
312 SectionIndexMapTy &SectionIndexMap);
314 virtual void WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout,
315 const MCSectionData &SD);
317 virtual void WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout) {
318 for (MCAssembler::const_iterator it = Asm.begin(),
319 ie = Asm.end(); it != ie; ++it) {
320 WriteRelocation(Asm, Layout, *it);
324 virtual void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout,
325 const SectionIndexMapTy &SectionIndexMap);
327 virtual void CreateGroupSections(MCAssembler &Asm, MCAsmLayout &Layout,
328 GroupMapTy &GroupMap, RevGroupMapTy &RevGroupMap);
330 virtual void ExecutePostLayoutBinding(MCAssembler &Asm);
332 virtual void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
333 uint64_t Address, uint64_t Offset,
334 uint64_t Size, uint32_t Link, uint32_t Info,
335 uint64_t Alignment, uint64_t EntrySize);
337 virtual void WriteRelocationsFragment(const MCAssembler &Asm, MCDataFragment *F,
338 const MCSectionData *SD);
340 virtual bool IsFixupFullyResolved(const MCAssembler &Asm,
341 const MCValue Target,
343 const MCFragment *DF) const;
345 virtual void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
346 virtual void WriteSection(MCAssembler &Asm,
347 const SectionIndexMapTy &SectionIndexMap,
348 uint32_t GroupSymbolIndex,
349 uint64_t Offset, uint64_t Size, uint64_t Alignment,
350 const MCSectionELF &Section);
353 //===- X86ELFObjectWriter -------------------------------------------===//
355 class X86ELFObjectWriter : public ELFObjectWriter {
357 X86ELFObjectWriter(raw_ostream &_OS, bool _Is64Bit, bool IsLittleEndian,
358 uint16_t _EMachine, bool _HasRelAddend,
359 Triple::OSType _OSType);
361 virtual ~X86ELFObjectWriter();
362 virtual void RecordRelocation(const MCAssembler &Asm,
363 const MCAsmLayout &Layout,
364 const MCFragment *Fragment,
365 const MCFixup &Fixup, MCValue Target,
366 uint64_t &FixedValue);
369 static bool isFixupKindPCRel(unsigned Kind) {
376 case X86::reloc_riprel_4byte:
377 case X86::reloc_riprel_4byte_movq_load:
384 //===- ARMELFObjectWriter -------------------------------------------===//
386 class ARMELFObjectWriter : public ELFObjectWriter {
388 ARMELFObjectWriter(raw_ostream &_OS, bool _Is64Bit, bool IsLittleEndian,
389 uint16_t _EMachine, bool _HasRelAddend,
390 Triple::OSType _OSType);
392 virtual ~ARMELFObjectWriter();
393 virtual void RecordRelocation(const MCAssembler &Asm,
394 const MCAsmLayout &Layout,
395 const MCFragment *Fragment,
396 const MCFixup &Fixup, MCValue Target,
397 uint64_t &FixedValue);
400 // Fixme: pull up to ELFObjectWriter
401 unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
404 static bool isFixupKindPCRel(unsigned Kind) {
411 case ARM::fixup_arm_ldst_pcrel_12:
412 case ARM::fixup_arm_pcrel_10:
413 case ARM::fixup_arm_branch:
419 //===- MBlazeELFObjectWriter -------------------------------------------===//
421 class MBlazeELFObjectWriter : public ELFObjectWriter {
423 MBlazeELFObjectWriter(raw_ostream &_OS, bool _Is64Bit, bool IsLittleEndian,
424 uint16_t _EMachine, bool _HasRelAddend,
425 Triple::OSType _OSType);
427 virtual ~MBlazeELFObjectWriter();
428 virtual void RecordRelocation(const MCAssembler &Asm,
429 const MCAsmLayout &Layout,
430 const MCFragment *Fragment,
431 const MCFixup &Fixup, MCValue Target,
432 uint64_t &FixedValue);
435 static bool isFixupKindPCRel(unsigned Kind) {
448 ELFObjectWriter::~ELFObjectWriter()
451 // Emit the ELF header.
452 void ELFObjectWriter::WriteHeader(uint64_t SectionDataSize,
453 unsigned NumberOfSections) {
459 // emitWord method behaves differently for ELF32 and ELF64, writing
460 // 4 bytes in the former and 8 in the latter.
462 Write8(0x7f); // e_ident[EI_MAG0]
463 Write8('E'); // e_ident[EI_MAG1]
464 Write8('L'); // e_ident[EI_MAG2]
465 Write8('F'); // e_ident[EI_MAG3]
467 Write8(Is64Bit ? ELF::ELFCLASS64 : ELF::ELFCLASS32); // e_ident[EI_CLASS]
470 Write8(isLittleEndian() ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
472 Write8(ELF::EV_CURRENT); // e_ident[EI_VERSION]
475 case Triple::FreeBSD: Write8(ELF::ELFOSABI_FREEBSD); break;
476 case Triple::Linux: Write8(ELF::ELFOSABI_LINUX); break;
477 default: Write8(ELF::ELFOSABI_NONE); break;
479 Write8(0); // e_ident[EI_ABIVERSION]
481 WriteZeros(ELF::EI_NIDENT - ELF::EI_PAD);
483 Write16(ELF::ET_REL); // e_type
485 Write16(EMachine); // e_machine = target
487 Write32(ELF::EV_CURRENT); // e_version
488 WriteWord(0); // e_entry, no entry point in .o file
489 WriteWord(0); // e_phoff, no program header for .o
490 WriteWord(SectionDataSize + (Is64Bit ? sizeof(ELF::Elf64_Ehdr) :
491 sizeof(ELF::Elf32_Ehdr))); // e_shoff = sec hdr table off in bytes
493 // FIXME: Make this configurable.
494 Write32(0); // e_flags = whatever the target wants
496 // e_ehsize = ELF header size
497 Write16(Is64Bit ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr));
499 Write16(0); // e_phentsize = prog header entry size
500 Write16(0); // e_phnum = # prog header entries = 0
502 // e_shentsize = Section header entry size
503 Write16(Is64Bit ? sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr));
505 // e_shnum = # of section header ents
506 if (NumberOfSections >= ELF::SHN_LORESERVE)
509 Write16(NumberOfSections);
511 // e_shstrndx = Section # of '.shstrtab'
512 if (NumberOfSections >= ELF::SHN_LORESERVE)
513 Write16(ELF::SHN_XINDEX);
515 Write16(ShstrtabIndex);
518 void ELFObjectWriter::WriteSymbolEntry(MCDataFragment *SymtabF,
519 MCDataFragment *ShndxF,
521 uint8_t info, uint64_t value,
522 uint64_t size, uint8_t other,
526 if (shndx >= ELF::SHN_LORESERVE && !Reserved)
527 String32(*ShndxF, shndx);
529 String32(*ShndxF, 0);
532 uint16_t Index = (shndx >= ELF::SHN_LORESERVE && !Reserved) ?
533 uint16_t(ELF::SHN_XINDEX) : shndx;
536 String32(*SymtabF, name); // st_name
537 String8(*SymtabF, info); // st_info
538 String8(*SymtabF, other); // st_other
539 String16(*SymtabF, Index); // st_shndx
540 String64(*SymtabF, value); // st_value
541 String64(*SymtabF, size); // st_size
543 String32(*SymtabF, name); // st_name
544 String32(*SymtabF, value); // st_value
545 String32(*SymtabF, size); // st_size
546 String8(*SymtabF, info); // st_info
547 String8(*SymtabF, other); // st_other
548 String16(*SymtabF, Index); // st_shndx
552 static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout) {
553 if (Data.isCommon() && Data.isExternal())
554 return Data.getCommonAlignment();
556 const MCSymbol &Symbol = Data.getSymbol();
557 if (!Symbol.isInSection())
560 if (MCFragment *FF = Data.getFragment())
561 return Layout.getSymbolAddress(&Data) -
562 Layout.getSectionAddress(FF->getParent());
567 void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm) {
568 // The presence of symbol versions causes undefined symbols and
569 // versions declared with @@@ to be renamed.
571 for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
572 ie = Asm.symbol_end(); it != ie; ++it) {
573 const MCSymbol &Alias = it->getSymbol();
574 const MCSymbol &Symbol = Alias.AliasedSymbol();
575 MCSymbolData &SD = Asm.getSymbolData(Symbol);
578 if (&Symbol == &Alias)
581 StringRef AliasName = Alias.getName();
582 size_t Pos = AliasName.find('@');
583 if (Pos == StringRef::npos)
586 // Aliases defined with .symvar copy the binding from the symbol they alias.
587 // This is the first place we are able to copy this information.
588 it->setExternal(SD.isExternal());
589 SetBinding(*it, GetBinding(SD));
591 StringRef Rest = AliasName.substr(Pos);
592 if (!Symbol.isUndefined() && !Rest.startswith("@@@"))
595 // FIXME: produce a better error message.
596 if (Symbol.isUndefined() && Rest.startswith("@@") &&
597 !Rest.startswith("@@@"))
598 report_fatal_error("A @@ version cannot be undefined");
600 Renames.insert(std::make_pair(&Symbol, &Alias));
604 void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF,
605 MCDataFragment *ShndxF,
607 const MCAsmLayout &Layout) {
608 MCSymbolData &OrigData = *MSD.SymbolData;
610 Layout.getAssembler().getSymbolData(OrigData.getSymbol().AliasedSymbol());
612 bool IsReserved = Data.isCommon() || Data.getSymbol().isAbsolute() ||
613 Data.getSymbol().isVariable();
615 uint8_t Binding = GetBinding(OrigData);
616 uint8_t Visibility = GetVisibility(OrigData);
617 uint8_t Type = GetType(Data);
619 uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift);
620 uint8_t Other = Visibility;
622 uint64_t Value = SymbolValue(Data, Layout);
626 assert(!(Data.isCommon() && !Data.isExternal()));
628 ESize = Data.getSize();
629 if (Data.getSize()) {
631 if (ESize->getKind() == MCExpr::Binary) {
632 const MCBinaryExpr *BE = static_cast<const MCBinaryExpr *>(ESize);
634 if (BE->EvaluateAsRelocatable(Res, &Layout)) {
635 assert(!Res.getSymA() || !Res.getSymA()->getSymbol().isDefined());
636 assert(!Res.getSymB() || !Res.getSymB()->getSymbol().isDefined());
637 Size = Res.getConstant();
639 } else if (ESize->getKind() == MCExpr::Constant) {
640 Size = static_cast<const MCConstantExpr *>(ESize)->getValue();
642 assert(0 && "Unsupported size expression");
646 // Write out the symbol table entry
647 WriteSymbolEntry(SymtabF, ShndxF, MSD.StringIndex, Info, Value,
648 Size, Other, MSD.SectionIndex, IsReserved);
651 void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF,
652 MCDataFragment *ShndxF,
653 const MCAssembler &Asm,
654 const MCAsmLayout &Layout,
655 const SectionIndexMapTy &SectionIndexMap) {
656 // The string table must be emitted first because we need the index
657 // into the string table for all the symbol names.
658 assert(StringTable.size() && "Missing string table");
660 // FIXME: Make sure the start of the symbol table is aligned.
662 // The first entry is the undefined symbol entry.
663 WriteSymbolEntry(SymtabF, ShndxF, 0, 0, 0, 0, 0, 0, false);
665 // Write the symbol table entries.
666 LastLocalSymbolIndex = LocalSymbolData.size() + 1;
667 for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) {
668 ELFSymbolData &MSD = LocalSymbolData[i];
669 WriteSymbol(SymtabF, ShndxF, MSD, Layout);
672 // Write out a symbol table entry for each regular section.
673 for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e;
675 const MCSectionELF &Section =
676 static_cast<const MCSectionELF&>(i->getSection());
677 if (Section.getType() == ELF::SHT_RELA ||
678 Section.getType() == ELF::SHT_REL ||
679 Section.getType() == ELF::SHT_STRTAB ||
680 Section.getType() == ELF::SHT_SYMTAB)
682 WriteSymbolEntry(SymtabF, ShndxF, 0, ELF::STT_SECTION, 0, 0,
683 ELF::STV_DEFAULT, SectionIndexMap.lookup(&Section), false);
684 LastLocalSymbolIndex++;
687 for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) {
688 ELFSymbolData &MSD = ExternalSymbolData[i];
689 MCSymbolData &Data = *MSD.SymbolData;
690 assert(((Data.getFlags() & ELF_STB_Global) ||
691 (Data.getFlags() & ELF_STB_Weak)) &&
692 "External symbol requires STB_GLOBAL or STB_WEAK flag");
693 WriteSymbol(SymtabF, ShndxF, MSD, Layout);
694 if (GetBinding(Data) == ELF::STB_LOCAL)
695 LastLocalSymbolIndex++;
698 for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) {
699 ELFSymbolData &MSD = UndefinedSymbolData[i];
700 MCSymbolData &Data = *MSD.SymbolData;
701 WriteSymbol(SymtabF, ShndxF, MSD, Layout);
702 if (GetBinding(Data) == ELF::STB_LOCAL)
703 LastLocalSymbolIndex++;
707 const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm,
708 const MCValue &Target,
709 const MCFragment &F) const {
710 const MCSymbol &Symbol = Target.getSymA()->getSymbol();
711 const MCSymbol &ASymbol = Symbol.AliasedSymbol();
712 const MCSymbol *Renamed = Renames.lookup(&Symbol);
713 const MCSymbolData &SD = Asm.getSymbolData(Symbol);
715 if (ASymbol.isUndefined()) {
721 if (SD.isExternal()) {
727 const MCSectionELF &Section =
728 static_cast<const MCSectionELF&>(ASymbol.getSection());
729 const SectionKind secKind = Section.getKind();
734 if (secKind.isThreadLocal()) {
740 MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind();
741 const MCSectionELF &Sec2 =
742 static_cast<const MCSectionELF&>(F.getParent()->getSection());
744 if (&Sec2 != &Section &&
745 (Kind == MCSymbolRefExpr::VK_PLT ||
746 Kind == MCSymbolRefExpr::VK_GOTPCREL ||
747 Kind == MCSymbolRefExpr::VK_GOTOFF)) {
753 if (Section.getFlags() & MCSectionELF::SHF_MERGE) {
754 if (Target.getConstant() == 0)
766 ELFObjectWriter::getSymbolIndexInSymbolTable(const MCAssembler &Asm,
768 MCSymbolData &SD = Asm.getSymbolData(*S);
769 return SD.getIndex();
772 static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data,
773 bool Used, bool Renamed) {
774 if (Data.getFlags() & ELF_Other_Weakref)
783 const MCSymbol &Symbol = Data.getSymbol();
785 if (Symbol.getName() == "_GLOBAL_OFFSET_TABLE_")
788 const MCSymbol &A = Symbol.AliasedSymbol();
789 if (!A.isVariable() && A.isUndefined() && !Data.isCommon())
792 if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
795 if (Symbol.isTemporary())
801 static bool isLocal(const MCSymbolData &Data, bool isSignature,
802 bool isUsedInReloc) {
803 if (Data.isExternal())
806 const MCSymbol &Symbol = Data.getSymbol();
807 const MCSymbol &RefSymbol = Symbol.AliasedSymbol();
809 if (RefSymbol.isUndefined() && !RefSymbol.isVariable()) {
810 if (isSignature && !isUsedInReloc)
819 void ELFObjectWriter::ComputeIndexMap(MCAssembler &Asm,
820 SectionIndexMapTy &SectionIndexMap) {
822 for (MCAssembler::iterator it = Asm.begin(),
823 ie = Asm.end(); it != ie; ++it) {
824 const MCSectionELF &Section =
825 static_cast<const MCSectionELF &>(it->getSection());
826 if (Section.getType() != ELF::SHT_GROUP)
828 SectionIndexMap[&Section] = Index++;
831 for (MCAssembler::iterator it = Asm.begin(),
832 ie = Asm.end(); it != ie; ++it) {
833 const MCSectionELF &Section =
834 static_cast<const MCSectionELF &>(it->getSection());
835 if (Section.getType() == ELF::SHT_GROUP)
837 SectionIndexMap[&Section] = Index++;
841 void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm,
842 const SectionIndexMapTy &SectionIndexMap,
843 RevGroupMapTy RevGroupMap) {
844 // FIXME: Is this the correct place to do this?
846 llvm::StringRef Name = "_GLOBAL_OFFSET_TABLE_";
847 MCSymbol *Sym = Asm.getContext().GetOrCreateSymbol(Name);
848 MCSymbolData &Data = Asm.getOrCreateSymbolData(*Sym);
849 Data.setExternal(true);
850 SetBinding(Data, ELF::STB_GLOBAL);
853 // Build section lookup table.
854 int NumRegularSections = Asm.size();
856 // Index 0 is always the empty string.
857 StringMap<uint64_t> StringIndexMap;
858 StringTable += '\x00';
860 // Add the data for the symbols.
861 for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
862 ie = Asm.symbol_end(); it != ie; ++it) {
863 const MCSymbol &Symbol = it->getSymbol();
865 bool Used = UsedInReloc.count(&Symbol);
866 bool WeakrefUsed = WeakrefUsedInReloc.count(&Symbol);
867 bool isSignature = RevGroupMap.count(&Symbol);
869 if (!isInSymtab(Asm, *it,
870 Used || WeakrefUsed || isSignature,
871 Renames.count(&Symbol)))
876 const MCSymbol &RefSymbol = Symbol.AliasedSymbol();
878 // Undefined symbols are global, but this is the first place we
879 // are able to set it.
880 bool Local = isLocal(*it, isSignature, Used);
881 if (!Local && GetBinding(*it) == ELF::STB_LOCAL) {
882 MCSymbolData &SD = Asm.getSymbolData(RefSymbol);
883 SetBinding(*it, ELF::STB_GLOBAL);
884 SetBinding(SD, ELF::STB_GLOBAL);
887 if (RefSymbol.isUndefined() && !Used && WeakrefUsed)
888 SetBinding(*it, ELF::STB_WEAK);
890 if (it->isCommon()) {
892 MSD.SectionIndex = ELF::SHN_COMMON;
893 } else if (Symbol.isAbsolute() || RefSymbol.isVariable()) {
894 MSD.SectionIndex = ELF::SHN_ABS;
895 } else if (RefSymbol.isUndefined()) {
896 if (isSignature && !Used)
897 MSD.SectionIndex = SectionIndexMap.lookup(RevGroupMap[&Symbol]);
899 MSD.SectionIndex = ELF::SHN_UNDEF;
901 const MCSectionELF &Section =
902 static_cast<const MCSectionELF&>(RefSymbol.getSection());
903 MSD.SectionIndex = SectionIndexMap.lookup(&Section);
904 if (MSD.SectionIndex >= ELF::SHN_LORESERVE)
905 NeedsSymtabShndx = true;
906 assert(MSD.SectionIndex && "Invalid section index!");
909 // The @@@ in symbol version is replaced with @ in undefined symbols and
910 // @@ in defined ones.
911 StringRef Name = Symbol.getName();
914 size_t Pos = Name.find("@@@");
915 if (Pos != StringRef::npos) {
916 Buf += Name.substr(0, Pos);
917 unsigned Skip = MSD.SectionIndex == ELF::SHN_UNDEF ? 2 : 1;
918 Buf += Name.substr(Pos + Skip);
922 uint64_t &Entry = StringIndexMap[Name];
924 Entry = StringTable.size();
926 StringTable += '\x00';
928 MSD.StringIndex = Entry;
929 if (MSD.SectionIndex == ELF::SHN_UNDEF)
930 UndefinedSymbolData.push_back(MSD);
932 LocalSymbolData.push_back(MSD);
934 ExternalSymbolData.push_back(MSD);
937 // Symbols are required to be in lexicographic order.
938 array_pod_sort(LocalSymbolData.begin(), LocalSymbolData.end());
939 array_pod_sort(ExternalSymbolData.begin(), ExternalSymbolData.end());
940 array_pod_sort(UndefinedSymbolData.begin(), UndefinedSymbolData.end());
942 // Set the symbol indices. Local symbols must come before all other
943 // symbols with non-local bindings.
945 for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
946 LocalSymbolData[i].SymbolData->setIndex(Index++);
948 Index += NumRegularSections;
950 for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
951 ExternalSymbolData[i].SymbolData->setIndex(Index++);
952 for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
953 UndefinedSymbolData[i].SymbolData->setIndex(Index++);
956 void ELFObjectWriter::WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout,
957 const MCSectionData &SD) {
958 if (!Relocations[&SD].empty()) {
959 MCContext &Ctx = Asm.getContext();
960 const MCSectionELF *RelaSection;
961 const MCSectionELF &Section =
962 static_cast<const MCSectionELF&>(SD.getSection());
964 const StringRef SectionName = Section.getSectionName();
965 std::string RelaSectionName = HasRelocationAddend ? ".rela" : ".rel";
966 RelaSectionName += SectionName;
969 if (HasRelocationAddend)
970 EntrySize = Is64Bit ? sizeof(ELF::Elf64_Rela) : sizeof(ELF::Elf32_Rela);
972 EntrySize = Is64Bit ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel);
974 RelaSection = Ctx.getELFSection(RelaSectionName, HasRelocationAddend ?
975 ELF::SHT_RELA : ELF::SHT_REL, 0,
976 SectionKind::getReadOnly(),
979 MCSectionData &RelaSD = Asm.getOrCreateSectionData(*RelaSection);
980 RelaSD.setAlignment(Is64Bit ? 8 : 4);
982 MCDataFragment *F = new MCDataFragment(&RelaSD);
984 WriteRelocationsFragment(Asm, F, &SD);
988 void ELFObjectWriter::WriteSecHdrEntry(uint32_t Name, uint32_t Type,
989 uint64_t Flags, uint64_t Address,
990 uint64_t Offset, uint64_t Size,
991 uint32_t Link, uint32_t Info,
993 uint64_t EntrySize) {
994 Write32(Name); // sh_name: index into string table
995 Write32(Type); // sh_type
996 WriteWord(Flags); // sh_flags
997 WriteWord(Address); // sh_addr
998 WriteWord(Offset); // sh_offset
999 WriteWord(Size); // sh_size
1000 Write32(Link); // sh_link
1001 Write32(Info); // sh_info
1002 WriteWord(Alignment); // sh_addralign
1003 WriteWord(EntrySize); // sh_entsize
1006 void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm,
1008 const MCSectionData *SD) {
1009 std::vector<ELFRelocationEntry> &Relocs = Relocations[SD];
1010 // sort by the r_offset just like gnu as does
1011 array_pod_sort(Relocs.begin(), Relocs.end());
1013 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
1014 ELFRelocationEntry entry = Relocs[e - i - 1];
1018 else if (entry.Index < 0)
1019 entry.Index = getSymbolIndexInSymbolTable(Asm, entry.Symbol);
1021 entry.Index += LocalSymbolData.size();
1023 String64(*F, entry.r_offset);
1025 struct ELF::Elf64_Rela ERE64;
1026 ERE64.setSymbolAndType(entry.Index, entry.Type);
1027 String64(*F, ERE64.r_info);
1029 if (HasRelocationAddend)
1030 String64(*F, entry.r_addend);
1032 String32(*F, entry.r_offset);
1034 struct ELF::Elf32_Rela ERE32;
1035 ERE32.setSymbolAndType(entry.Index, entry.Type);
1036 String32(*F, ERE32.r_info);
1038 if (HasRelocationAddend)
1039 String32(*F, entry.r_addend);
1044 void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm,
1045 MCAsmLayout &Layout,
1046 const SectionIndexMapTy &SectionIndexMap) {
1047 MCContext &Ctx = Asm.getContext();
1050 unsigned EntrySize = Is64Bit ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
1052 // We construct .shstrtab, .symtab and .strtab in this order to match gnu as.
1053 const MCSectionELF *ShstrtabSection =
1054 Ctx.getELFSection(".shstrtab", ELF::SHT_STRTAB, 0,
1055 SectionKind::getReadOnly());
1056 MCSectionData &ShstrtabSD = Asm.getOrCreateSectionData(*ShstrtabSection);
1057 ShstrtabSD.setAlignment(1);
1058 ShstrtabIndex = Asm.size();
1060 const MCSectionELF *SymtabSection =
1061 Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
1062 SectionKind::getReadOnly(),
1064 MCSectionData &SymtabSD = Asm.getOrCreateSectionData(*SymtabSection);
1065 SymtabSD.setAlignment(Is64Bit ? 8 : 4);
1066 SymbolTableIndex = Asm.size();
1068 MCSectionData *SymtabShndxSD = NULL;
1070 if (NeedsSymtabShndx) {
1071 const MCSectionELF *SymtabShndxSection =
1072 Ctx.getELFSection(".symtab_shndx", ELF::SHT_SYMTAB_SHNDX, 0,
1073 SectionKind::getReadOnly(), 4, "");
1074 SymtabShndxSD = &Asm.getOrCreateSectionData(*SymtabShndxSection);
1075 SymtabShndxSD->setAlignment(4);
1078 const MCSection *StrtabSection;
1079 StrtabSection = Ctx.getELFSection(".strtab", ELF::SHT_STRTAB, 0,
1080 SectionKind::getReadOnly());
1081 MCSectionData &StrtabSD = Asm.getOrCreateSectionData(*StrtabSection);
1082 StrtabSD.setAlignment(1);
1083 StringTableIndex = Asm.size();
1085 WriteRelocations(Asm, Layout);
1088 F = new MCDataFragment(&SymtabSD);
1089 MCDataFragment *ShndxF = NULL;
1090 if (NeedsSymtabShndx) {
1091 ShndxF = new MCDataFragment(SymtabShndxSD);
1093 WriteSymbolTable(F, ShndxF, Asm, Layout, SectionIndexMap);
1095 F = new MCDataFragment(&StrtabSD);
1096 F->getContents().append(StringTable.begin(), StringTable.end());
1098 F = new MCDataFragment(&ShstrtabSD);
1100 // Section header string table.
1102 // The first entry of a string table holds a null character so skip
1105 F->getContents() += '\x00';
1107 StringMap<uint64_t> SecStringMap;
1108 for (MCAssembler::const_iterator it = Asm.begin(),
1109 ie = Asm.end(); it != ie; ++it) {
1110 const MCSectionELF &Section =
1111 static_cast<const MCSectionELF&>(it->getSection());
1112 // FIXME: We could merge suffixes like in .text and .rela.text.
1114 StringRef Name = Section.getSectionName();
1115 if (SecStringMap.count(Name)) {
1116 SectionStringTableIndex[&Section] = SecStringMap[Name];
1119 // Remember the index into the string table so we can write it
1120 // into the sh_name field of the section header table.
1121 SectionStringTableIndex[&Section] = Index;
1122 SecStringMap[Name] = Index;
1124 Index += Name.size() + 1;
1125 F->getContents() += Name;
1126 F->getContents() += '\x00';
1130 bool ELFObjectWriter::IsFixupFullyResolved(const MCAssembler &Asm,
1131 const MCValue Target,
1133 const MCFragment *DF) const {
1134 // If this is a PCrel relocation, find the section this fixup value is
1136 const MCSection *BaseSection = 0;
1138 BaseSection = &DF->getParent()->getSection();
1139 assert(BaseSection);
1142 const MCSection *SectionA = 0;
1143 const MCSymbol *SymbolA = 0;
1144 if (const MCSymbolRefExpr *A = Target.getSymA()) {
1145 SymbolA = &A->getSymbol();
1146 SectionA = &SymbolA->AliasedSymbol().getSection();
1149 const MCSection *SectionB = 0;
1150 const MCSymbol *SymbolB = 0;
1151 if (const MCSymbolRefExpr *B = Target.getSymB()) {
1152 SymbolB = &B->getSymbol();
1153 SectionB = &SymbolB->AliasedSymbol().getSection();
1157 return SectionA == SectionB;
1162 // Absolute address but PCrel instruction, so we need a relocation.
1166 // FIXME: This is in here just to match gnu as output. If the two ends
1167 // are in the same section, there is nothing that the linker can do to
1169 const MCSymbolData &DataA = Asm.getSymbolData(*SymbolA);
1170 if (DataA.isExternal())
1173 return BaseSection == SectionA;
1176 void ELFObjectWriter::CreateGroupSections(MCAssembler &Asm,
1177 MCAsmLayout &Layout,
1178 GroupMapTy &GroupMap,
1179 RevGroupMapTy &RevGroupMap) {
1181 for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
1183 const MCSectionELF &Section =
1184 static_cast<const MCSectionELF&>(it->getSection());
1185 if (!(Section.getFlags() & MCSectionELF::SHF_GROUP))
1188 const MCSymbol *SignatureSymbol = Section.getGroup();
1189 Asm.getOrCreateSymbolData(*SignatureSymbol);
1190 const MCSectionELF *&Group = RevGroupMap[SignatureSymbol];
1192 Group = Asm.getContext().CreateELFGroupSection();
1193 MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
1194 Data.setAlignment(4);
1195 MCDataFragment *F = new MCDataFragment(&Data);
1196 String32(*F, ELF::GRP_COMDAT);
1198 GroupMap[Group] = SignatureSymbol;
1201 // Add sections to the groups
1203 unsigned NumGroups = RevGroupMap.size();
1204 for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
1205 it != ie; ++it, ++Index) {
1206 const MCSectionELF &Section =
1207 static_cast<const MCSectionELF&>(it->getSection());
1208 if (!(Section.getFlags() & MCSectionELF::SHF_GROUP))
1210 const MCSectionELF *Group = RevGroupMap[Section.getGroup()];
1211 MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
1212 // FIXME: we could use the previous fragment
1213 MCDataFragment *F = new MCDataFragment(&Data);
1214 String32(*F, NumGroups + Index);
1218 void ELFObjectWriter::WriteSection(MCAssembler &Asm,
1219 const SectionIndexMapTy &SectionIndexMap,
1220 uint32_t GroupSymbolIndex,
1221 uint64_t Offset, uint64_t Size,
1223 const MCSectionELF &Section) {
1224 uint64_t sh_link = 0;
1225 uint64_t sh_info = 0;
1227 switch(Section.getType()) {
1228 case ELF::SHT_DYNAMIC:
1229 sh_link = SectionStringTableIndex[&Section];
1234 case ELF::SHT_RELA: {
1235 const MCSectionELF *SymtabSection;
1236 const MCSectionELF *InfoSection;
1237 SymtabSection = Asm.getContext().getELFSection(".symtab", ELF::SHT_SYMTAB,
1239 SectionKind::getReadOnly());
1240 sh_link = SectionIndexMap.lookup(SymtabSection);
1241 assert(sh_link && ".symtab not found");
1243 // Remove ".rel" and ".rela" prefixes.
1244 unsigned SecNameLen = (Section.getType() == ELF::SHT_REL) ? 4 : 5;
1245 StringRef SectionName = Section.getSectionName().substr(SecNameLen);
1247 InfoSection = Asm.getContext().getELFSection(SectionName,
1248 ELF::SHT_PROGBITS, 0,
1249 SectionKind::getReadOnly());
1250 sh_info = SectionIndexMap.lookup(InfoSection);
1254 case ELF::SHT_SYMTAB:
1255 case ELF::SHT_DYNSYM:
1256 sh_link = StringTableIndex;
1257 sh_info = LastLocalSymbolIndex;
1260 case ELF::SHT_SYMTAB_SHNDX:
1261 sh_link = SymbolTableIndex;
1264 case ELF::SHT_PROGBITS:
1265 case ELF::SHT_STRTAB:
1266 case ELF::SHT_NOBITS:
1268 case ELF::SHT_ARM_ATTRIBUTES:
1272 case ELF::SHT_GROUP: {
1273 sh_link = SymbolTableIndex;
1274 sh_info = GroupSymbolIndex;
1279 assert(0 && "FIXME: sh_type value not supported!");
1283 WriteSecHdrEntry(SectionStringTableIndex[&Section], Section.getType(),
1284 Section.getFlags(), 0, Offset, Size, sh_link, sh_info,
1285 Alignment, Section.getEntrySize());
1288 static bool IsELFMetaDataSection(const MCSectionData &SD) {
1289 return SD.getAddress() == ~UINT64_C(0) &&
1290 !SD.getSection().isVirtualSection();
1293 static uint64_t DataSectionSize(const MCSectionData &SD) {
1295 for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e;
1297 const MCFragment &F = *i;
1298 assert(F.getKind() == MCFragment::FT_Data);
1299 Ret += cast<MCDataFragment>(F).getContents().size();
1304 static uint64_t GetSectionFileSize(const MCAsmLayout &Layout,
1305 const MCSectionData &SD) {
1306 if (IsELFMetaDataSection(SD))
1307 return DataSectionSize(SD);
1308 return Layout.getSectionFileSize(&SD);
1311 static uint64_t GetSectionSize(const MCAsmLayout &Layout,
1312 const MCSectionData &SD) {
1313 if (IsELFMetaDataSection(SD))
1314 return DataSectionSize(SD);
1315 return Layout.getSectionSize(&SD);
1318 static void WriteDataSectionData(ELFObjectWriter *W, const MCSectionData &SD) {
1319 for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e;
1321 const MCFragment &F = *i;
1322 assert(F.getKind() == MCFragment::FT_Data);
1323 W->WriteBytes(cast<MCDataFragment>(F).getContents().str());
1327 void ELFObjectWriter::WriteObject(MCAssembler &Asm,
1328 const MCAsmLayout &Layout) {
1329 GroupMapTy GroupMap;
1330 RevGroupMapTy RevGroupMap;
1331 CreateGroupSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap,
1334 SectionIndexMapTy SectionIndexMap;
1336 ComputeIndexMap(Asm, SectionIndexMap);
1338 // Compute symbol table information.
1339 ComputeSymbolTable(Asm, SectionIndexMap, RevGroupMap);
1341 CreateMetadataSections(const_cast<MCAssembler&>(Asm),
1342 const_cast<MCAsmLayout&>(Layout),
1345 // Update to include the metadata sections.
1346 ComputeIndexMap(Asm, SectionIndexMap);
1348 // Add 1 for the null section.
1349 unsigned NumSections = Asm.size() + 1;
1350 uint64_t NaturalAlignment = Is64Bit ? 8 : 4;
1351 uint64_t HeaderSize = Is64Bit ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr);
1352 uint64_t FileOff = HeaderSize;
1354 std::vector<const MCSectionELF*> Sections;
1355 Sections.resize(NumSections);
1357 for (SectionIndexMapTy::const_iterator i=
1358 SectionIndexMap.begin(), e = SectionIndexMap.end(); i != e; ++i) {
1359 const std::pair<const MCSectionELF*, uint32_t> &p = *i;
1360 Sections[p.second] = p.first;
1363 for (unsigned i = 1; i < NumSections; ++i) {
1364 const MCSectionELF &Section = *Sections[i];
1365 const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
1367 FileOff = RoundUpToAlignment(FileOff, SD.getAlignment());
1369 // Get the size of the section in the output file (including padding).
1370 FileOff += GetSectionFileSize(Layout, SD);
1373 FileOff = RoundUpToAlignment(FileOff, NaturalAlignment);
1375 // Write out the ELF header ...
1376 WriteHeader(FileOff - HeaderSize, NumSections);
1378 FileOff = HeaderSize;
1380 // ... then all of the sections ...
1381 DenseMap<const MCSection*, uint64_t> SectionOffsetMap;
1383 for (unsigned i = 1; i < NumSections; ++i) {
1384 const MCSectionELF &Section = *Sections[i];
1385 const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
1387 uint64_t Padding = OffsetToAlignment(FileOff, SD.getAlignment());
1388 WriteZeros(Padding);
1391 // Remember the offset into the file for this section.
1392 SectionOffsetMap[&Section] = FileOff;
1394 FileOff += GetSectionFileSize(Layout, SD);
1396 if (IsELFMetaDataSection(SD))
1397 WriteDataSectionData(this, SD);
1399 Asm.WriteSectionData(&SD, Layout, this);
1402 uint64_t Padding = OffsetToAlignment(FileOff, NaturalAlignment);
1403 WriteZeros(Padding);
1406 // ... and then the section header table.
1407 // Should we align the section header table?
1409 // Null section first.
1410 uint64_t FirstSectionSize =
1411 NumSections >= ELF::SHN_LORESERVE ? NumSections : 0;
1412 uint32_t FirstSectionLink =
1413 ShstrtabIndex >= ELF::SHN_LORESERVE ? ShstrtabIndex : 0;
1414 WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, FirstSectionLink, 0, 0, 0);
1416 for (unsigned i = 1; i < NumSections; ++i) {
1417 const MCSectionELF &Section = *Sections[i];
1418 const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
1419 uint32_t GroupSymbolIndex;
1420 if (Section.getType() != ELF::SHT_GROUP)
1421 GroupSymbolIndex = 0;
1423 GroupSymbolIndex = getSymbolIndexInSymbolTable(Asm, GroupMap[&Section]);
1425 uint64_t Size = GetSectionSize(Layout, SD);
1427 WriteSection(Asm, SectionIndexMap, GroupSymbolIndex,
1428 SectionOffsetMap[&Section], Size,
1429 SD.getAlignment(), Section);
1433 MCObjectWriter *llvm::createELFObjectWriter(raw_ostream &OS,
1435 Triple::OSType OSType,
1437 bool IsLittleEndian,
1438 bool HasRelocationAddend) {
1441 case ELF::EM_X86_64:
1442 return new X86ELFObjectWriter(OS, Is64Bit, IsLittleEndian, EMachine,
1443 HasRelocationAddend, OSType); break;
1445 return new ARMELFObjectWriter(OS, Is64Bit, IsLittleEndian, EMachine,
1446 HasRelocationAddend, OSType); break;
1447 case ELF::EM_MBLAZE:
1448 return new MBlazeELFObjectWriter(OS, Is64Bit, IsLittleEndian, EMachine,
1449 HasRelocationAddend, OSType); break;
1450 default: llvm_unreachable("Unsupported architecture"); break;
1455 /// START OF SUBCLASSES for ELFObjectWriter
1456 //===- ARMELFObjectWriter -------------------------------------------===//
1458 ARMELFObjectWriter::ARMELFObjectWriter(raw_ostream &_OS, bool _Is64Bit,
1459 bool _IsLittleEndian,
1460 uint16_t _EMachine, bool _HasRelocationAddend,
1461 Triple::OSType _OSType)
1462 : ELFObjectWriter(_OS, _Is64Bit, _IsLittleEndian, _EMachine,
1463 _HasRelocationAddend, _OSType)
1466 ARMELFObjectWriter::~ARMELFObjectWriter()
1469 unsigned ARMELFObjectWriter::GetRelocType(const MCValue &Target,
1470 const MCFixup &Fixup,
1472 MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
1473 MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
1477 default: assert(0 && "Unimplemented Modifier");
1478 case MCSymbolRefExpr::VK_None: break;
1480 switch ((unsigned)Fixup.getKind()) {
1481 default: assert(0 && "Unimplemented");
1482 case ARM::fixup_arm_branch: return ELF::R_ARM_CALL; break;
1485 switch ((unsigned)Fixup.getKind()) {
1486 default: llvm_unreachable("invalid fixup kind!");
1487 case ARM::fixup_arm_ldst_pcrel_12:
1488 case ARM::fixup_arm_pcrel_10:
1489 case ARM::fixup_arm_adr_pcrel_12:
1490 assert(0 && "Unimplemented"); break;
1491 case ARM::fixup_arm_branch:
1492 return ELF::R_ARM_CALL; break;
1493 case ARM::fixup_arm_movt_hi16:
1494 return ELF::R_ARM_MOVT_ABS; break;
1495 case ARM::fixup_arm_movw_lo16:
1496 return ELF::R_ARM_MOVW_ABS_NC; break;
1500 if (RelocNeedsGOT(Modifier))
1505 void ARMELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
1506 const MCAsmLayout &Layout,
1507 const MCFragment *Fragment,
1508 const MCFixup &Fixup,
1510 uint64_t &FixedValue) {
1513 int64_t Value = Target.getConstant();
1514 const MCSymbol *RelocSymbol = NULL;
1516 bool IsPCRel = isFixupKindPCRel(Fixup.getKind());
1517 if (!Target.isAbsolute()) {
1518 const MCSymbol &Symbol = Target.getSymA()->getSymbol();
1519 const MCSymbol &ASymbol = Symbol.AliasedSymbol();
1520 RelocSymbol = SymbolToReloc(Asm, Target, *Fragment);
1522 if (const MCSymbolRefExpr *RefB = Target.getSymB()) {
1523 const MCSymbol &SymbolB = RefB->getSymbol();
1524 MCSymbolData &SDB = Asm.getSymbolData(SymbolB);
1526 MCSectionData *Sec = Fragment->getParent();
1528 // Offset of the symbol in the section
1529 int64_t a = Layout.getSymbolAddress(&SDB) - Layout.getSectionAddress(Sec);
1531 // Ofeset of the relocation in the section
1532 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
1537 MCSymbolData &SD = Asm.getSymbolData(ASymbol);
1538 MCFragment *F = SD.getFragment();
1540 Index = F->getParent()->getOrdinal() + 1;
1542 MCSectionData *FSD = F->getParent();
1543 // Offset of the symbol in the section
1544 Value += Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD);
1546 if (Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
1547 WeakrefUsedInReloc.insert(RelocSymbol);
1549 UsedInReloc.insert(RelocSymbol);
1553 // Compensate for the addend on i386.
1560 // determine the type of the relocation
1561 unsigned Type = GetRelocType(Target, Fixup, IsPCRel);
1563 uint64_t RelocOffset = Layout.getFragmentOffset(Fragment) +
1566 if (!HasRelocationAddend) Addend = 0;
1567 ELFRelocationEntry ERE(RelocOffset, Index, Type, RelocSymbol, Addend);
1568 Relocations[Fragment->getParent()].push_back(ERE);
1571 //===- MBlazeELFObjectWriter -------------------------------------------===//
1573 MBlazeELFObjectWriter::MBlazeELFObjectWriter(raw_ostream &_OS, bool _Is64Bit,
1574 bool _IsLittleEndian,
1576 bool _HasRelocationAddend,
1577 Triple::OSType _OSType)
1578 : ELFObjectWriter(_OS, _Is64Bit, _IsLittleEndian, _EMachine,
1579 _HasRelocationAddend, _OSType) {
1582 MBlazeELFObjectWriter::~MBlazeELFObjectWriter() {
1585 void MBlazeELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
1586 const MCAsmLayout &Layout,
1587 const MCFragment *Fragment,
1588 const MCFixup &Fixup,
1590 uint64_t &FixedValue) {
1593 int64_t Value = Target.getConstant();
1594 const MCSymbol &Symbol = Target.getSymA()->getSymbol();
1595 const MCSymbol &ASymbol = Symbol.AliasedSymbol();
1596 const MCSymbol *RelocSymbol = SymbolToReloc(Asm, Target, *Fragment);
1598 bool IsPCRel = isFixupKindPCRel(Fixup.getKind());
1599 if (!Target.isAbsolute()) {
1600 if (const MCSymbolRefExpr *RefB = Target.getSymB()) {
1601 const MCSymbol &SymbolB = RefB->getSymbol();
1602 MCSymbolData &SDB = Asm.getSymbolData(SymbolB);
1604 MCSectionData *Sec = Fragment->getParent();
1606 // Offset of the symbol in the section
1607 int64_t a = Layout.getSymbolAddress(&SDB) - Layout.getSectionAddress(Sec);
1609 // Ofeset of the relocation in the section
1610 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
1615 MCSymbolData &SD = Asm.getSymbolData(ASymbol);
1616 MCFragment *F = SD.getFragment();
1618 Index = F->getParent()->getOrdinal();
1620 MCSectionData *FSD = F->getParent();
1621 // Offset of the symbol in the section
1622 Value += Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD);
1624 if (Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
1625 WeakrefUsedInReloc.insert(RelocSymbol);
1627 UsedInReloc.insert(RelocSymbol);
1635 // determine the type of the relocation
1638 switch ((unsigned)Fixup.getKind()) {
1640 llvm_unreachable("Unimplemented");
1642 Type = ELF::R_MICROBLAZE_64_PCREL;
1645 Type = ELF::R_MICROBLAZE_32_PCREL;
1649 switch ((unsigned)Fixup.getKind()) {
1650 default: llvm_unreachable("invalid fixup kind!");
1652 Type = (RelocSymbol || Addend !=0) ? ELF::R_MICROBLAZE_32
1653 : ELF::R_MICROBLAZE_64;
1656 Type = ELF::R_MICROBLAZE_32;
1661 MCSymbolRefExpr::VariantKind Modifier = Target.getSymA()->getKind();
1662 if (RelocNeedsGOT(Modifier))
1665 uint64_t RelocOffset = Layout.getFragmentOffset(Fragment) +
1668 if (!HasRelocationAddend) Addend = 0;
1669 ELFRelocationEntry ERE(RelocOffset, Index, Type, RelocSymbol, Addend);
1670 Relocations[Fragment->getParent()].push_back(ERE);
1673 //===- X86ELFObjectWriter -------------------------------------------===//
1676 X86ELFObjectWriter::X86ELFObjectWriter(raw_ostream &_OS, bool _Is64Bit,
1677 bool _IsLittleEndian,
1678 uint16_t _EMachine, bool _HasRelocationAddend,
1679 Triple::OSType _OSType)
1680 : ELFObjectWriter(_OS, _Is64Bit, _IsLittleEndian, _EMachine,
1681 _HasRelocationAddend, _OSType)
1684 X86ELFObjectWriter::~X86ELFObjectWriter()
1687 void X86ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
1688 const MCAsmLayout &Layout,
1689 const MCFragment *Fragment,
1690 const MCFixup &Fixup,
1692 uint64_t &FixedValue) {
1695 int64_t Value = Target.getConstant();
1696 const MCSymbol *RelocSymbol = NULL;
1698 bool IsPCRel = isFixupKindPCRel(Fixup.getKind());
1699 if (!Target.isAbsolute()) {
1700 const MCSymbol &Symbol = Target.getSymA()->getSymbol();
1701 const MCSymbol &ASymbol = Symbol.AliasedSymbol();
1702 RelocSymbol = SymbolToReloc(Asm, Target, *Fragment);
1704 if (const MCSymbolRefExpr *RefB = Target.getSymB()) {
1705 const MCSymbol &SymbolB = RefB->getSymbol();
1706 MCSymbolData &SDB = Asm.getSymbolData(SymbolB);
1708 MCSectionData *Sec = Fragment->getParent();
1710 // Offset of the symbol in the section
1711 int64_t a = Layout.getSymbolAddress(&SDB) - Layout.getSectionAddress(Sec);
1713 // Ofeset of the relocation in the section
1714 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
1719 MCSymbolData &SD = Asm.getSymbolData(ASymbol);
1720 MCFragment *F = SD.getFragment();
1722 Index = F->getParent()->getOrdinal() + 1;
1724 MCSectionData *FSD = F->getParent();
1725 // Offset of the symbol in the section
1726 Value += Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD);
1728 if (Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
1729 WeakrefUsedInReloc.insert(RelocSymbol);
1731 UsedInReloc.insert(RelocSymbol);
1735 // Compensate for the addend on i386.
1742 // determine the type of the relocation
1744 MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
1745 MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
1751 llvm_unreachable("Unimplemented");
1752 case MCSymbolRefExpr::VK_None:
1753 Type = ELF::R_X86_64_PC32;
1755 case MCSymbolRefExpr::VK_PLT:
1756 Type = ELF::R_X86_64_PLT32;
1758 case MCSymbolRefExpr::VK_GOTPCREL:
1759 Type = ELF::R_X86_64_GOTPCREL;
1761 case MCSymbolRefExpr::VK_GOTTPOFF:
1762 Type = ELF::R_X86_64_GOTTPOFF;
1764 case MCSymbolRefExpr::VK_TLSGD:
1765 Type = ELF::R_X86_64_TLSGD;
1767 case MCSymbolRefExpr::VK_TLSLD:
1768 Type = ELF::R_X86_64_TLSLD;
1772 switch ((unsigned)Fixup.getKind()) {
1773 default: llvm_unreachable("invalid fixup kind!");
1774 case FK_Data_8: Type = ELF::R_X86_64_64; break;
1775 case X86::reloc_signed_4byte:
1777 assert(isInt<32>(Target.getConstant()));
1780 llvm_unreachable("Unimplemented");
1781 case MCSymbolRefExpr::VK_None:
1782 Type = ELF::R_X86_64_32S;
1784 case MCSymbolRefExpr::VK_GOT:
1785 Type = ELF::R_X86_64_GOT32;
1787 case MCSymbolRefExpr::VK_GOTPCREL:
1788 Type = ELF::R_X86_64_GOTPCREL;
1790 case MCSymbolRefExpr::VK_TPOFF:
1791 Type = ELF::R_X86_64_TPOFF32;
1793 case MCSymbolRefExpr::VK_DTPOFF:
1794 Type = ELF::R_X86_64_DTPOFF32;
1799 Type = ELF::R_X86_64_32;
1801 case FK_Data_2: Type = ELF::R_X86_64_16; break;
1803 case FK_Data_1: Type = ELF::R_X86_64_8; break;
1810 llvm_unreachable("Unimplemented");
1811 case MCSymbolRefExpr::VK_None:
1812 Type = ELF::R_386_PC32;
1814 case MCSymbolRefExpr::VK_PLT:
1815 Type = ELF::R_386_PLT32;
1819 switch ((unsigned)Fixup.getKind()) {
1820 default: llvm_unreachable("invalid fixup kind!");
1822 case X86::reloc_global_offset_table:
1823 Type = ELF::R_386_GOTPC;
1826 // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode
1828 case X86::reloc_signed_4byte:
1833 llvm_unreachable("Unimplemented");
1834 case MCSymbolRefExpr::VK_None:
1835 Type = ELF::R_386_32;
1837 case MCSymbolRefExpr::VK_GOT:
1838 Type = ELF::R_386_GOT32;
1840 case MCSymbolRefExpr::VK_GOTOFF:
1841 Type = ELF::R_386_GOTOFF;
1843 case MCSymbolRefExpr::VK_TLSGD:
1844 Type = ELF::R_386_TLS_GD;
1846 case MCSymbolRefExpr::VK_TPOFF:
1847 Type = ELF::R_386_TLS_LE_32;
1849 case MCSymbolRefExpr::VK_INDNTPOFF:
1850 Type = ELF::R_386_TLS_IE;
1852 case MCSymbolRefExpr::VK_NTPOFF:
1853 Type = ELF::R_386_TLS_LE;
1855 case MCSymbolRefExpr::VK_GOTNTPOFF:
1856 Type = ELF::R_386_TLS_GOTIE;
1858 case MCSymbolRefExpr::VK_TLSLDM:
1859 Type = ELF::R_386_TLS_LDM;
1861 case MCSymbolRefExpr::VK_DTPOFF:
1862 Type = ELF::R_386_TLS_LDO_32;
1866 case FK_Data_2: Type = ELF::R_386_16; break;
1868 case FK_Data_1: Type = ELF::R_386_8; break;
1873 if (RelocNeedsGOT(Modifier))
1877 uint64_t RelocOffset = Layout.getFragmentOffset(Fragment) +
1880 if (!HasRelocationAddend) Addend = 0;
1881 ELFRelocationEntry ERE(RelocOffset, Index, Type, RelocSymbol, Addend);
1882 Relocations[Fragment->getParent()].push_back(ERE);