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 static bool isFixupKindPCRel(unsigned Kind) {
407 case ARM::fixup_arm_pcrel_12:
408 case ARM::fixup_arm_vfp_pcrel_12:
409 case ARM::fixup_arm_branch:
415 //===- MBlazeELFObjectWriter -------------------------------------------===//
417 class MBlazeELFObjectWriter : public ELFObjectWriter {
419 MBlazeELFObjectWriter(raw_ostream &_OS, bool _Is64Bit, bool IsLittleEndian,
420 uint16_t _EMachine, bool _HasRelAddend,
421 Triple::OSType _OSType);
423 virtual ~MBlazeELFObjectWriter();
424 virtual void RecordRelocation(const MCAssembler &Asm,
425 const MCAsmLayout &Layout,
426 const MCFragment *Fragment,
427 const MCFixup &Fixup, MCValue Target,
428 uint64_t &FixedValue);
431 static bool isFixupKindPCRel(unsigned Kind) {
444 ELFObjectWriter::~ELFObjectWriter()
447 // Emit the ELF header.
448 void ELFObjectWriter::WriteHeader(uint64_t SectionDataSize,
449 unsigned NumberOfSections) {
455 // emitWord method behaves differently for ELF32 and ELF64, writing
456 // 4 bytes in the former and 8 in the latter.
458 Write8(0x7f); // e_ident[EI_MAG0]
459 Write8('E'); // e_ident[EI_MAG1]
460 Write8('L'); // e_ident[EI_MAG2]
461 Write8('F'); // e_ident[EI_MAG3]
463 Write8(Is64Bit ? ELF::ELFCLASS64 : ELF::ELFCLASS32); // e_ident[EI_CLASS]
466 Write8(isLittleEndian() ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
468 Write8(ELF::EV_CURRENT); // e_ident[EI_VERSION]
471 case Triple::FreeBSD: Write8(ELF::ELFOSABI_FREEBSD); break;
472 case Triple::Linux: Write8(ELF::ELFOSABI_LINUX); break;
473 default: Write8(ELF::ELFOSABI_NONE); break;
475 Write8(0); // e_ident[EI_ABIVERSION]
477 WriteZeros(ELF::EI_NIDENT - ELF::EI_PAD);
479 Write16(ELF::ET_REL); // e_type
481 Write16(EMachine); // e_machine = target
483 Write32(ELF::EV_CURRENT); // e_version
484 WriteWord(0); // e_entry, no entry point in .o file
485 WriteWord(0); // e_phoff, no program header for .o
486 WriteWord(SectionDataSize + (Is64Bit ? sizeof(ELF::Elf64_Ehdr) :
487 sizeof(ELF::Elf32_Ehdr))); // e_shoff = sec hdr table off in bytes
489 // FIXME: Make this configurable.
490 Write32(0); // e_flags = whatever the target wants
492 // e_ehsize = ELF header size
493 Write16(Is64Bit ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr));
495 Write16(0); // e_phentsize = prog header entry size
496 Write16(0); // e_phnum = # prog header entries = 0
498 // e_shentsize = Section header entry size
499 Write16(Is64Bit ? sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr));
501 // e_shnum = # of section header ents
502 if (NumberOfSections >= ELF::SHN_LORESERVE)
505 Write16(NumberOfSections);
507 // e_shstrndx = Section # of '.shstrtab'
508 if (NumberOfSections >= ELF::SHN_LORESERVE)
509 Write16(ELF::SHN_XINDEX);
511 Write16(ShstrtabIndex);
514 void ELFObjectWriter::WriteSymbolEntry(MCDataFragment *SymtabF,
515 MCDataFragment *ShndxF,
517 uint8_t info, uint64_t value,
518 uint64_t size, uint8_t other,
522 if (shndx >= ELF::SHN_LORESERVE && !Reserved)
523 String32(*ShndxF, shndx);
525 String32(*ShndxF, 0);
528 uint16_t Index = (shndx >= ELF::SHN_LORESERVE && !Reserved) ?
529 uint16_t(ELF::SHN_XINDEX) : shndx;
532 String32(*SymtabF, name); // st_name
533 String8(*SymtabF, info); // st_info
534 String8(*SymtabF, other); // st_other
535 String16(*SymtabF, Index); // st_shndx
536 String64(*SymtabF, value); // st_value
537 String64(*SymtabF, size); // st_size
539 String32(*SymtabF, name); // st_name
540 String32(*SymtabF, value); // st_value
541 String32(*SymtabF, size); // st_size
542 String8(*SymtabF, info); // st_info
543 String8(*SymtabF, other); // st_other
544 String16(*SymtabF, Index); // st_shndx
548 static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout) {
549 if (Data.isCommon() && Data.isExternal())
550 return Data.getCommonAlignment();
552 const MCSymbol &Symbol = Data.getSymbol();
553 if (!Symbol.isInSection())
556 if (MCFragment *FF = Data.getFragment())
557 return Layout.getSymbolAddress(&Data) -
558 Layout.getSectionAddress(FF->getParent());
563 void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm) {
564 // The presence of symbol versions causes undefined symbols and
565 // versions declared with @@@ to be renamed.
567 for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
568 ie = Asm.symbol_end(); it != ie; ++it) {
569 const MCSymbol &Alias = it->getSymbol();
570 const MCSymbol &Symbol = Alias.AliasedSymbol();
571 MCSymbolData &SD = Asm.getSymbolData(Symbol);
574 if (&Symbol == &Alias)
577 StringRef AliasName = Alias.getName();
578 size_t Pos = AliasName.find('@');
579 if (Pos == StringRef::npos)
582 // Aliases defined with .symvar copy the binding from the symbol they alias.
583 // This is the first place we are able to copy this information.
584 it->setExternal(SD.isExternal());
585 SetBinding(*it, GetBinding(SD));
587 StringRef Rest = AliasName.substr(Pos);
588 if (!Symbol.isUndefined() && !Rest.startswith("@@@"))
591 // FIXME: produce a better error message.
592 if (Symbol.isUndefined() && Rest.startswith("@@") &&
593 !Rest.startswith("@@@"))
594 report_fatal_error("A @@ version cannot be undefined");
596 Renames.insert(std::make_pair(&Symbol, &Alias));
600 void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF,
601 MCDataFragment *ShndxF,
603 const MCAsmLayout &Layout) {
604 MCSymbolData &OrigData = *MSD.SymbolData;
606 Layout.getAssembler().getSymbolData(OrigData.getSymbol().AliasedSymbol());
608 bool IsReserved = Data.isCommon() || Data.getSymbol().isAbsolute() ||
609 Data.getSymbol().isVariable();
611 uint8_t Binding = GetBinding(OrigData);
612 uint8_t Visibility = GetVisibility(OrigData);
613 uint8_t Type = GetType(Data);
615 uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift);
616 uint8_t Other = Visibility;
618 uint64_t Value = SymbolValue(Data, Layout);
622 assert(!(Data.isCommon() && !Data.isExternal()));
624 ESize = Data.getSize();
625 if (Data.getSize()) {
627 if (ESize->getKind() == MCExpr::Binary) {
628 const MCBinaryExpr *BE = static_cast<const MCBinaryExpr *>(ESize);
630 if (BE->EvaluateAsRelocatable(Res, &Layout)) {
631 assert(!Res.getSymA() || !Res.getSymA()->getSymbol().isDefined());
632 assert(!Res.getSymB() || !Res.getSymB()->getSymbol().isDefined());
633 Size = Res.getConstant();
635 } else if (ESize->getKind() == MCExpr::Constant) {
636 Size = static_cast<const MCConstantExpr *>(ESize)->getValue();
638 assert(0 && "Unsupported size expression");
642 // Write out the symbol table entry
643 WriteSymbolEntry(SymtabF, ShndxF, MSD.StringIndex, Info, Value,
644 Size, Other, MSD.SectionIndex, IsReserved);
647 void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF,
648 MCDataFragment *ShndxF,
649 const MCAssembler &Asm,
650 const MCAsmLayout &Layout,
651 const SectionIndexMapTy &SectionIndexMap) {
652 // The string table must be emitted first because we need the index
653 // into the string table for all the symbol names.
654 assert(StringTable.size() && "Missing string table");
656 // FIXME: Make sure the start of the symbol table is aligned.
658 // The first entry is the undefined symbol entry.
659 WriteSymbolEntry(SymtabF, ShndxF, 0, 0, 0, 0, 0, 0, false);
661 // Write the symbol table entries.
662 LastLocalSymbolIndex = LocalSymbolData.size() + 1;
663 for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) {
664 ELFSymbolData &MSD = LocalSymbolData[i];
665 WriteSymbol(SymtabF, ShndxF, MSD, Layout);
668 // Write out a symbol table entry for each regular section.
669 for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e;
671 const MCSectionELF &Section =
672 static_cast<const MCSectionELF&>(i->getSection());
673 if (Section.getType() == ELF::SHT_RELA ||
674 Section.getType() == ELF::SHT_REL ||
675 Section.getType() == ELF::SHT_STRTAB ||
676 Section.getType() == ELF::SHT_SYMTAB)
678 WriteSymbolEntry(SymtabF, ShndxF, 0, ELF::STT_SECTION, 0, 0,
679 ELF::STV_DEFAULT, SectionIndexMap.lookup(&Section), false);
680 LastLocalSymbolIndex++;
683 for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) {
684 ELFSymbolData &MSD = ExternalSymbolData[i];
685 MCSymbolData &Data = *MSD.SymbolData;
686 assert(((Data.getFlags() & ELF_STB_Global) ||
687 (Data.getFlags() & ELF_STB_Weak)) &&
688 "External symbol requires STB_GLOBAL or STB_WEAK flag");
689 WriteSymbol(SymtabF, ShndxF, MSD, Layout);
690 if (GetBinding(Data) == ELF::STB_LOCAL)
691 LastLocalSymbolIndex++;
694 for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) {
695 ELFSymbolData &MSD = UndefinedSymbolData[i];
696 MCSymbolData &Data = *MSD.SymbolData;
697 WriteSymbol(SymtabF, ShndxF, MSD, Layout);
698 if (GetBinding(Data) == ELF::STB_LOCAL)
699 LastLocalSymbolIndex++;
703 const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm,
704 const MCValue &Target,
705 const MCFragment &F) const {
706 const MCSymbol &Symbol = Target.getSymA()->getSymbol();
707 const MCSymbol &ASymbol = Symbol.AliasedSymbol();
708 const MCSymbol *Renamed = Renames.lookup(&Symbol);
709 const MCSymbolData &SD = Asm.getSymbolData(Symbol);
711 if (ASymbol.isUndefined()) {
717 if (SD.isExternal()) {
723 const MCSectionELF &Section =
724 static_cast<const MCSectionELF&>(ASymbol.getSection());
725 const SectionKind secKind = Section.getKind();
730 if (secKind.isThreadLocal()) {
736 MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind();
737 const MCSectionELF &Sec2 =
738 static_cast<const MCSectionELF&>(F.getParent()->getSection());
740 if (&Sec2 != &Section &&
741 (Kind == MCSymbolRefExpr::VK_PLT ||
742 Kind == MCSymbolRefExpr::VK_GOTPCREL ||
743 Kind == MCSymbolRefExpr::VK_GOTOFF)) {
749 if (Section.getFlags() & MCSectionELF::SHF_MERGE) {
750 if (Target.getConstant() == 0)
762 ELFObjectWriter::getSymbolIndexInSymbolTable(const MCAssembler &Asm,
764 MCSymbolData &SD = Asm.getSymbolData(*S);
765 return SD.getIndex();
768 static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data,
769 bool Used, bool Renamed) {
770 if (Data.getFlags() & ELF_Other_Weakref)
779 const MCSymbol &Symbol = Data.getSymbol();
781 if (Symbol.getName() == "_GLOBAL_OFFSET_TABLE_")
784 const MCSymbol &A = Symbol.AliasedSymbol();
785 if (!A.isVariable() && A.isUndefined() && !Data.isCommon())
788 if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
791 if (Symbol.isTemporary())
797 static bool isLocal(const MCSymbolData &Data, bool isSignature,
798 bool isUsedInReloc) {
799 if (Data.isExternal())
802 const MCSymbol &Symbol = Data.getSymbol();
803 const MCSymbol &RefSymbol = Symbol.AliasedSymbol();
805 if (RefSymbol.isUndefined() && !RefSymbol.isVariable()) {
806 if (isSignature && !isUsedInReloc)
815 void ELFObjectWriter::ComputeIndexMap(MCAssembler &Asm,
816 SectionIndexMapTy &SectionIndexMap) {
818 for (MCAssembler::iterator it = Asm.begin(),
819 ie = Asm.end(); it != ie; ++it) {
820 const MCSectionELF &Section =
821 static_cast<const MCSectionELF &>(it->getSection());
822 if (Section.getType() != ELF::SHT_GROUP)
824 SectionIndexMap[&Section] = Index++;
827 for (MCAssembler::iterator it = Asm.begin(),
828 ie = Asm.end(); it != ie; ++it) {
829 const MCSectionELF &Section =
830 static_cast<const MCSectionELF &>(it->getSection());
831 if (Section.getType() == ELF::SHT_GROUP)
833 SectionIndexMap[&Section] = Index++;
837 void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm,
838 const SectionIndexMapTy &SectionIndexMap,
839 RevGroupMapTy RevGroupMap) {
840 // FIXME: Is this the correct place to do this?
842 llvm::StringRef Name = "_GLOBAL_OFFSET_TABLE_";
843 MCSymbol *Sym = Asm.getContext().GetOrCreateSymbol(Name);
844 MCSymbolData &Data = Asm.getOrCreateSymbolData(*Sym);
845 Data.setExternal(true);
846 SetBinding(Data, ELF::STB_GLOBAL);
849 // Build section lookup table.
850 int NumRegularSections = Asm.size();
852 // Index 0 is always the empty string.
853 StringMap<uint64_t> StringIndexMap;
854 StringTable += '\x00';
856 // Add the data for the symbols.
857 for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
858 ie = Asm.symbol_end(); it != ie; ++it) {
859 const MCSymbol &Symbol = it->getSymbol();
861 bool Used = UsedInReloc.count(&Symbol);
862 bool WeakrefUsed = WeakrefUsedInReloc.count(&Symbol);
863 bool isSignature = RevGroupMap.count(&Symbol);
865 if (!isInSymtab(Asm, *it,
866 Used || WeakrefUsed || isSignature,
867 Renames.count(&Symbol)))
872 const MCSymbol &RefSymbol = Symbol.AliasedSymbol();
874 // Undefined symbols are global, but this is the first place we
875 // are able to set it.
876 bool Local = isLocal(*it, isSignature, Used);
877 if (!Local && GetBinding(*it) == ELF::STB_LOCAL) {
878 MCSymbolData &SD = Asm.getSymbolData(RefSymbol);
879 SetBinding(*it, ELF::STB_GLOBAL);
880 SetBinding(SD, ELF::STB_GLOBAL);
883 if (RefSymbol.isUndefined() && !Used && WeakrefUsed)
884 SetBinding(*it, ELF::STB_WEAK);
886 if (it->isCommon()) {
888 MSD.SectionIndex = ELF::SHN_COMMON;
889 } else if (Symbol.isAbsolute() || RefSymbol.isVariable()) {
890 MSD.SectionIndex = ELF::SHN_ABS;
891 } else if (RefSymbol.isUndefined()) {
892 if (isSignature && !Used)
893 MSD.SectionIndex = SectionIndexMap.lookup(RevGroupMap[&Symbol]);
895 MSD.SectionIndex = ELF::SHN_UNDEF;
897 const MCSectionELF &Section =
898 static_cast<const MCSectionELF&>(RefSymbol.getSection());
899 MSD.SectionIndex = SectionIndexMap.lookup(&Section);
900 if (MSD.SectionIndex >= ELF::SHN_LORESERVE)
901 NeedsSymtabShndx = true;
902 assert(MSD.SectionIndex && "Invalid section index!");
905 // The @@@ in symbol version is replaced with @ in undefined symbols and
906 // @@ in defined ones.
907 StringRef Name = Symbol.getName();
910 size_t Pos = Name.find("@@@");
911 if (Pos != StringRef::npos) {
912 Buf += Name.substr(0, Pos);
913 unsigned Skip = MSD.SectionIndex == ELF::SHN_UNDEF ? 2 : 1;
914 Buf += Name.substr(Pos + Skip);
918 uint64_t &Entry = StringIndexMap[Name];
920 Entry = StringTable.size();
922 StringTable += '\x00';
924 MSD.StringIndex = Entry;
925 if (MSD.SectionIndex == ELF::SHN_UNDEF)
926 UndefinedSymbolData.push_back(MSD);
928 LocalSymbolData.push_back(MSD);
930 ExternalSymbolData.push_back(MSD);
933 // Symbols are required to be in lexicographic order.
934 array_pod_sort(LocalSymbolData.begin(), LocalSymbolData.end());
935 array_pod_sort(ExternalSymbolData.begin(), ExternalSymbolData.end());
936 array_pod_sort(UndefinedSymbolData.begin(), UndefinedSymbolData.end());
938 // Set the symbol indices. Local symbols must come before all other
939 // symbols with non-local bindings.
941 for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
942 LocalSymbolData[i].SymbolData->setIndex(Index++);
944 Index += NumRegularSections;
946 for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
947 ExternalSymbolData[i].SymbolData->setIndex(Index++);
948 for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
949 UndefinedSymbolData[i].SymbolData->setIndex(Index++);
952 void ELFObjectWriter::WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout,
953 const MCSectionData &SD) {
954 if (!Relocations[&SD].empty()) {
955 MCContext &Ctx = Asm.getContext();
956 const MCSectionELF *RelaSection;
957 const MCSectionELF &Section =
958 static_cast<const MCSectionELF&>(SD.getSection());
960 const StringRef SectionName = Section.getSectionName();
961 std::string RelaSectionName = HasRelocationAddend ? ".rela" : ".rel";
962 RelaSectionName += SectionName;
965 if (HasRelocationAddend)
966 EntrySize = Is64Bit ? sizeof(ELF::Elf64_Rela) : sizeof(ELF::Elf32_Rela);
968 EntrySize = Is64Bit ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel);
970 RelaSection = Ctx.getELFSection(RelaSectionName, HasRelocationAddend ?
971 ELF::SHT_RELA : ELF::SHT_REL, 0,
972 SectionKind::getReadOnly(),
975 MCSectionData &RelaSD = Asm.getOrCreateSectionData(*RelaSection);
976 RelaSD.setAlignment(Is64Bit ? 8 : 4);
978 MCDataFragment *F = new MCDataFragment(&RelaSD);
980 WriteRelocationsFragment(Asm, F, &SD);
982 Asm.AddSectionToTheEnd(*this, RelaSD, Layout);
986 void ELFObjectWriter::WriteSecHdrEntry(uint32_t Name, uint32_t Type,
987 uint64_t Flags, uint64_t Address,
988 uint64_t Offset, uint64_t Size,
989 uint32_t Link, uint32_t Info,
991 uint64_t EntrySize) {
992 Write32(Name); // sh_name: index into string table
993 Write32(Type); // sh_type
994 WriteWord(Flags); // sh_flags
995 WriteWord(Address); // sh_addr
996 WriteWord(Offset); // sh_offset
997 WriteWord(Size); // sh_size
998 Write32(Link); // sh_link
999 Write32(Info); // sh_info
1000 WriteWord(Alignment); // sh_addralign
1001 WriteWord(EntrySize); // sh_entsize
1004 void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm,
1006 const MCSectionData *SD) {
1007 std::vector<ELFRelocationEntry> &Relocs = Relocations[SD];
1008 // sort by the r_offset just like gnu as does
1009 array_pod_sort(Relocs.begin(), Relocs.end());
1011 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
1012 ELFRelocationEntry entry = Relocs[e - i - 1];
1016 else if (entry.Index < 0)
1017 entry.Index = getSymbolIndexInSymbolTable(Asm, entry.Symbol);
1019 entry.Index += LocalSymbolData.size();
1021 String64(*F, entry.r_offset);
1023 struct ELF::Elf64_Rela ERE64;
1024 ERE64.setSymbolAndType(entry.Index, entry.Type);
1025 String64(*F, ERE64.r_info);
1027 if (HasRelocationAddend)
1028 String64(*F, entry.r_addend);
1030 String32(*F, entry.r_offset);
1032 struct ELF::Elf32_Rela ERE32;
1033 ERE32.setSymbolAndType(entry.Index, entry.Type);
1034 String32(*F, ERE32.r_info);
1036 if (HasRelocationAddend)
1037 String32(*F, entry.r_addend);
1042 void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm,
1043 MCAsmLayout &Layout,
1044 const SectionIndexMapTy &SectionIndexMap) {
1045 MCContext &Ctx = Asm.getContext();
1048 unsigned EntrySize = Is64Bit ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
1050 // We construct .shstrtab, .symtab and .strtab in this order to match gnu as.
1051 const MCSectionELF *ShstrtabSection =
1052 Ctx.getELFSection(".shstrtab", ELF::SHT_STRTAB, 0,
1053 SectionKind::getReadOnly());
1054 MCSectionData &ShstrtabSD = Asm.getOrCreateSectionData(*ShstrtabSection);
1055 ShstrtabSD.setAlignment(1);
1056 ShstrtabIndex = Asm.size();
1058 const MCSectionELF *SymtabSection =
1059 Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
1060 SectionKind::getReadOnly(),
1062 MCSectionData &SymtabSD = Asm.getOrCreateSectionData(*SymtabSection);
1063 SymtabSD.setAlignment(Is64Bit ? 8 : 4);
1064 SymbolTableIndex = Asm.size();
1066 MCSectionData *SymtabShndxSD = NULL;
1068 if (NeedsSymtabShndx) {
1069 const MCSectionELF *SymtabShndxSection =
1070 Ctx.getELFSection(".symtab_shndx", ELF::SHT_SYMTAB_SHNDX, 0,
1071 SectionKind::getReadOnly(), 4, "");
1072 SymtabShndxSD = &Asm.getOrCreateSectionData(*SymtabShndxSection);
1073 SymtabShndxSD->setAlignment(4);
1076 const MCSection *StrtabSection;
1077 StrtabSection = Ctx.getELFSection(".strtab", ELF::SHT_STRTAB, 0,
1078 SectionKind::getReadOnly());
1079 MCSectionData &StrtabSD = Asm.getOrCreateSectionData(*StrtabSection);
1080 StrtabSD.setAlignment(1);
1081 StringTableIndex = Asm.size();
1083 WriteRelocations(Asm, Layout);
1086 F = new MCDataFragment(&SymtabSD);
1087 MCDataFragment *ShndxF = NULL;
1088 if (NeedsSymtabShndx) {
1089 ShndxF = new MCDataFragment(SymtabShndxSD);
1090 Asm.AddSectionToTheEnd(*this, *SymtabShndxSD, Layout);
1092 WriteSymbolTable(F, ShndxF, Asm, Layout, SectionIndexMap);
1093 Asm.AddSectionToTheEnd(*this, SymtabSD, Layout);
1095 F = new MCDataFragment(&StrtabSD);
1096 F->getContents().append(StringTable.begin(), StringTable.end());
1097 Asm.AddSectionToTheEnd(*this, StrtabSD, Layout);
1099 F = new MCDataFragment(&ShstrtabSD);
1101 // Section header string table.
1103 // The first entry of a string table holds a null character so skip
1106 F->getContents() += '\x00';
1108 StringMap<uint64_t> SecStringMap;
1109 for (MCAssembler::const_iterator it = Asm.begin(),
1110 ie = Asm.end(); it != ie; ++it) {
1111 const MCSectionELF &Section =
1112 static_cast<const MCSectionELF&>(it->getSection());
1113 // FIXME: We could merge suffixes like in .text and .rela.text.
1115 StringRef Name = Section.getSectionName();
1116 if (SecStringMap.count(Name)) {
1117 SectionStringTableIndex[&Section] = SecStringMap[Name];
1120 // Remember the index into the string table so we can write it
1121 // into the sh_name field of the section header table.
1122 SectionStringTableIndex[&Section] = Index;
1123 SecStringMap[Name] = Index;
1125 Index += Name.size() + 1;
1126 F->getContents() += Name;
1127 F->getContents() += '\x00';
1130 Asm.AddSectionToTheEnd(*this, ShstrtabSD, Layout);
1133 bool ELFObjectWriter::IsFixupFullyResolved(const MCAssembler &Asm,
1134 const MCValue Target,
1136 const MCFragment *DF) const {
1137 // If this is a PCrel relocation, find the section this fixup value is
1139 const MCSection *BaseSection = 0;
1141 BaseSection = &DF->getParent()->getSection();
1142 assert(BaseSection);
1145 const MCSection *SectionA = 0;
1146 const MCSymbol *SymbolA = 0;
1147 if (const MCSymbolRefExpr *A = Target.getSymA()) {
1148 SymbolA = &A->getSymbol();
1149 SectionA = &SymbolA->AliasedSymbol().getSection();
1152 const MCSection *SectionB = 0;
1153 const MCSymbol *SymbolB = 0;
1154 if (const MCSymbolRefExpr *B = Target.getSymB()) {
1155 SymbolB = &B->getSymbol();
1156 SectionB = &SymbolB->AliasedSymbol().getSection();
1160 return SectionA == SectionB;
1165 // Absolute address but PCrel instruction, so we need a relocation.
1169 // FIXME: This is in here just to match gnu as output. If the two ends
1170 // are in the same section, there is nothing that the linker can do to
1172 const MCSymbolData &DataA = Asm.getSymbolData(*SymbolA);
1173 if (DataA.isExternal())
1176 return BaseSection == SectionA;
1179 void ELFObjectWriter::CreateGroupSections(MCAssembler &Asm,
1180 MCAsmLayout &Layout,
1181 GroupMapTy &GroupMap,
1182 RevGroupMapTy &RevGroupMap) {
1184 for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
1186 const MCSectionELF &Section =
1187 static_cast<const MCSectionELF&>(it->getSection());
1188 if (!(Section.getFlags() & MCSectionELF::SHF_GROUP))
1191 const MCSymbol *SignatureSymbol = Section.getGroup();
1192 Asm.getOrCreateSymbolData(*SignatureSymbol);
1193 const MCSectionELF *&Group = RevGroupMap[SignatureSymbol];
1195 Group = Asm.getContext().CreateELFGroupSection();
1196 MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
1197 Data.setAlignment(4);
1198 MCDataFragment *F = new MCDataFragment(&Data);
1199 String32(*F, ELF::GRP_COMDAT);
1201 GroupMap[Group] = SignatureSymbol;
1204 // Add sections to the groups
1206 unsigned NumGroups = RevGroupMap.size();
1207 for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
1208 it != ie; ++it, ++Index) {
1209 const MCSectionELF &Section =
1210 static_cast<const MCSectionELF&>(it->getSection());
1211 if (!(Section.getFlags() & MCSectionELF::SHF_GROUP))
1213 const MCSectionELF *Group = RevGroupMap[Section.getGroup()];
1214 MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
1215 // FIXME: we could use the previous fragment
1216 MCDataFragment *F = new MCDataFragment(&Data);
1217 String32(*F, NumGroups + Index);
1220 for (RevGroupMapTy::const_iterator i = RevGroupMap.begin(),
1221 e = RevGroupMap.end(); i != e; ++i) {
1222 const MCSectionELF *Group = i->second;
1223 MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
1224 Asm.AddSectionToTheEnd(*this, Data, Layout);
1228 void ELFObjectWriter::WriteSection(MCAssembler &Asm,
1229 const SectionIndexMapTy &SectionIndexMap,
1230 uint32_t GroupSymbolIndex,
1231 uint64_t Offset, uint64_t Size,
1233 const MCSectionELF &Section) {
1234 uint64_t sh_link = 0;
1235 uint64_t sh_info = 0;
1237 switch(Section.getType()) {
1238 case ELF::SHT_DYNAMIC:
1239 sh_link = SectionStringTableIndex[&Section];
1244 case ELF::SHT_RELA: {
1245 const MCSectionELF *SymtabSection;
1246 const MCSectionELF *InfoSection;
1247 SymtabSection = Asm.getContext().getELFSection(".symtab", ELF::SHT_SYMTAB,
1249 SectionKind::getReadOnly());
1250 sh_link = SectionIndexMap.lookup(SymtabSection);
1251 assert(sh_link && ".symtab not found");
1253 // Remove ".rel" and ".rela" prefixes.
1254 unsigned SecNameLen = (Section.getType() == ELF::SHT_REL) ? 4 : 5;
1255 StringRef SectionName = Section.getSectionName().substr(SecNameLen);
1257 InfoSection = Asm.getContext().getELFSection(SectionName,
1258 ELF::SHT_PROGBITS, 0,
1259 SectionKind::getReadOnly());
1260 sh_info = SectionIndexMap.lookup(InfoSection);
1264 case ELF::SHT_SYMTAB:
1265 case ELF::SHT_DYNSYM:
1266 sh_link = StringTableIndex;
1267 sh_info = LastLocalSymbolIndex;
1270 case ELF::SHT_SYMTAB_SHNDX:
1271 sh_link = SymbolTableIndex;
1274 case ELF::SHT_PROGBITS:
1275 case ELF::SHT_STRTAB:
1276 case ELF::SHT_NOBITS:
1278 case ELF::SHT_ARM_ATTRIBUTES:
1282 case ELF::SHT_GROUP: {
1283 sh_link = SymbolTableIndex;
1284 sh_info = GroupSymbolIndex;
1289 assert(0 && "FIXME: sh_type value not supported!");
1293 WriteSecHdrEntry(SectionStringTableIndex[&Section], Section.getType(),
1294 Section.getFlags(), 0, Offset, Size, sh_link, sh_info,
1295 Alignment, Section.getEntrySize());
1298 void ELFObjectWriter::WriteObject(MCAssembler &Asm,
1299 const MCAsmLayout &Layout) {
1300 GroupMapTy GroupMap;
1301 RevGroupMapTy RevGroupMap;
1302 CreateGroupSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap,
1305 SectionIndexMapTy SectionIndexMap;
1307 ComputeIndexMap(Asm, SectionIndexMap);
1309 // Compute symbol table information.
1310 ComputeSymbolTable(Asm, SectionIndexMap, RevGroupMap);
1312 CreateMetadataSections(const_cast<MCAssembler&>(Asm),
1313 const_cast<MCAsmLayout&>(Layout),
1316 // Update to include the metadata sections.
1317 ComputeIndexMap(Asm, SectionIndexMap);
1319 // Add 1 for the null section.
1320 unsigned NumSections = Asm.size() + 1;
1321 uint64_t NaturalAlignment = Is64Bit ? 8 : 4;
1322 uint64_t HeaderSize = Is64Bit ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr);
1323 uint64_t FileOff = HeaderSize;
1325 std::vector<const MCSectionELF*> Sections;
1326 Sections.resize(NumSections);
1328 for (SectionIndexMapTy::const_iterator i=
1329 SectionIndexMap.begin(), e = SectionIndexMap.end(); i != e; ++i) {
1330 const std::pair<const MCSectionELF*, uint32_t> &p = *i;
1331 Sections[p.second] = p.first;
1334 for (unsigned i = 1; i < NumSections; ++i) {
1335 const MCSectionELF &Section = *Sections[i];
1336 const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
1338 FileOff = RoundUpToAlignment(FileOff, SD.getAlignment());
1340 // Get the size of the section in the output file (including padding).
1341 uint64_t Size = Layout.getSectionFileSize(&SD);
1346 FileOff = RoundUpToAlignment(FileOff, NaturalAlignment);
1348 // Write out the ELF header ...
1349 WriteHeader(FileOff - HeaderSize, NumSections);
1351 FileOff = HeaderSize;
1353 // ... then all of the sections ...
1354 DenseMap<const MCSection*, uint64_t> SectionOffsetMap;
1356 for (unsigned i = 1; i < NumSections; ++i) {
1357 const MCSectionELF &Section = *Sections[i];
1358 const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
1360 uint64_t Padding = OffsetToAlignment(FileOff, SD.getAlignment());
1361 WriteZeros(Padding);
1364 // Remember the offset into the file for this section.
1365 SectionOffsetMap[&Section] = FileOff;
1367 FileOff += Layout.getSectionFileSize(&SD);
1369 Asm.WriteSectionData(&SD, Layout, this);
1372 uint64_t Padding = OffsetToAlignment(FileOff, NaturalAlignment);
1373 WriteZeros(Padding);
1376 // ... and then the section header table.
1377 // Should we align the section header table?
1379 // Null section first.
1380 uint64_t FirstSectionSize =
1381 NumSections >= ELF::SHN_LORESERVE ? NumSections : 0;
1382 uint32_t FirstSectionLink =
1383 ShstrtabIndex >= ELF::SHN_LORESERVE ? ShstrtabIndex : 0;
1384 WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, FirstSectionLink, 0, 0, 0);
1386 for (unsigned i = 1; i < NumSections; ++i) {
1387 const MCSectionELF &Section = *Sections[i];
1388 const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
1389 uint32_t GroupSymbolIndex;
1390 if (Section.getType() != ELF::SHT_GROUP)
1391 GroupSymbolIndex = 0;
1393 GroupSymbolIndex = getSymbolIndexInSymbolTable(Asm, GroupMap[&Section]);
1395 WriteSection(Asm, SectionIndexMap, GroupSymbolIndex,
1396 SectionOffsetMap[&Section], Layout.getSectionSize(&SD),
1397 SD.getAlignment(), Section);
1401 MCObjectWriter *llvm::createELFObjectWriter(raw_ostream &OS,
1403 Triple::OSType OSType,
1405 bool IsLittleEndian,
1406 bool HasRelocationAddend) {
1409 case ELF::EM_X86_64:
1410 return new X86ELFObjectWriter(OS, Is64Bit, IsLittleEndian, EMachine,
1411 HasRelocationAddend, OSType); break;
1413 return new ARMELFObjectWriter(OS, Is64Bit, IsLittleEndian, EMachine,
1414 HasRelocationAddend, OSType); break;
1415 case ELF::EM_MBLAZE:
1416 return new MBlazeELFObjectWriter(OS, Is64Bit, IsLittleEndian, EMachine,
1417 HasRelocationAddend, OSType); break;
1418 default: llvm_unreachable("Unsupported architecture"); break;
1423 /// START OF SUBCLASSES for ELFObjectWriter
1424 //===- ARMELFObjectWriter -------------------------------------------===//
1426 ARMELFObjectWriter::ARMELFObjectWriter(raw_ostream &_OS, bool _Is64Bit,
1427 bool _IsLittleEndian,
1428 uint16_t _EMachine, bool _HasRelocationAddend,
1429 Triple::OSType _OSType)
1430 : ELFObjectWriter(_OS, _Is64Bit, _IsLittleEndian, _EMachine,
1431 _HasRelocationAddend, _OSType)
1434 ARMELFObjectWriter::~ARMELFObjectWriter()
1437 void ARMELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
1438 const MCAsmLayout &Layout,
1439 const MCFragment *Fragment,
1440 const MCFixup &Fixup,
1442 uint64_t &FixedValue) {
1443 assert(0 && "ARMELFObjectWriter::RecordRelocation() unimplemented");
1446 //===- MBlazeELFObjectWriter -------------------------------------------===//
1448 MBlazeELFObjectWriter::MBlazeELFObjectWriter(raw_ostream &_OS, bool _Is64Bit,
1449 bool _IsLittleEndian,
1451 bool _HasRelocationAddend,
1452 Triple::OSType _OSType)
1453 : ELFObjectWriter(_OS, _Is64Bit, _IsLittleEndian, _EMachine,
1454 _HasRelocationAddend, _OSType) {
1457 MBlazeELFObjectWriter::~MBlazeELFObjectWriter() {
1460 void MBlazeELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
1461 const MCAsmLayout &Layout,
1462 const MCFragment *Fragment,
1463 const MCFixup &Fixup,
1465 uint64_t &FixedValue) {
1468 int64_t Value = Target.getConstant();
1469 const MCSymbol &Symbol = Target.getSymA()->getSymbol();
1470 const MCSymbol &ASymbol = Symbol.AliasedSymbol();
1471 const MCSymbol *RelocSymbol = SymbolToReloc(Asm, Target, *Fragment);
1473 bool IsPCRel = isFixupKindPCRel(Fixup.getKind());
1474 if (!Target.isAbsolute()) {
1475 if (const MCSymbolRefExpr *RefB = Target.getSymB()) {
1476 const MCSymbol &SymbolB = RefB->getSymbol();
1477 MCSymbolData &SDB = Asm.getSymbolData(SymbolB);
1479 MCSectionData *Sec = Fragment->getParent();
1481 // Offset of the symbol in the section
1482 int64_t a = Layout.getSymbolAddress(&SDB) - Layout.getSectionAddress(Sec);
1484 // Ofeset of the relocation in the section
1485 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
1490 MCSymbolData &SD = Asm.getSymbolData(ASymbol);
1491 MCFragment *F = SD.getFragment();
1493 Index = F->getParent()->getOrdinal();
1495 MCSectionData *FSD = F->getParent();
1496 // Offset of the symbol in the section
1497 Value += Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD);
1499 if (Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
1500 WeakrefUsedInReloc.insert(RelocSymbol);
1502 UsedInReloc.insert(RelocSymbol);
1510 // determine the type of the relocation
1513 switch ((unsigned)Fixup.getKind()) {
1515 llvm_unreachable("Unimplemented");
1517 Type = ELF::R_MICROBLAZE_64_PCREL;
1520 Type = ELF::R_MICROBLAZE_32_PCREL;
1524 switch ((unsigned)Fixup.getKind()) {
1525 default: llvm_unreachable("invalid fixup kind!");
1527 Type = (RelocSymbol || Addend !=0) ? ELF::R_MICROBLAZE_32
1528 : ELF::R_MICROBLAZE_64;
1531 Type = ELF::R_MICROBLAZE_32;
1536 MCSymbolRefExpr::VariantKind Modifier = Target.getSymA()->getKind();
1537 if (RelocNeedsGOT(Modifier))
1540 uint64_t RelocOffset = Layout.getFragmentOffset(Fragment) +
1543 if (!HasRelocationAddend) Addend = 0;
1544 ELFRelocationEntry ERE(RelocOffset, Index, Type, RelocSymbol, Addend);
1545 Relocations[Fragment->getParent()].push_back(ERE);
1548 //===- X86ELFObjectWriter -------------------------------------------===//
1551 X86ELFObjectWriter::X86ELFObjectWriter(raw_ostream &_OS, bool _Is64Bit,
1552 bool _IsLittleEndian,
1553 uint16_t _EMachine, bool _HasRelocationAddend,
1554 Triple::OSType _OSType)
1555 : ELFObjectWriter(_OS, _Is64Bit, _IsLittleEndian, _EMachine,
1556 _HasRelocationAddend, _OSType)
1559 X86ELFObjectWriter::~X86ELFObjectWriter()
1562 void X86ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
1563 const MCAsmLayout &Layout,
1564 const MCFragment *Fragment,
1565 const MCFixup &Fixup,
1567 uint64_t &FixedValue) {
1570 int64_t Value = Target.getConstant();
1571 const MCSymbol *RelocSymbol = NULL;
1573 bool IsPCRel = isFixupKindPCRel(Fixup.getKind());
1574 if (!Target.isAbsolute()) {
1575 const MCSymbol &Symbol = Target.getSymA()->getSymbol();
1576 const MCSymbol &ASymbol = Symbol.AliasedSymbol();
1577 RelocSymbol = SymbolToReloc(Asm, Target, *Fragment);
1579 if (const MCSymbolRefExpr *RefB = Target.getSymB()) {
1580 const MCSymbol &SymbolB = RefB->getSymbol();
1581 MCSymbolData &SDB = Asm.getSymbolData(SymbolB);
1583 MCSectionData *Sec = Fragment->getParent();
1585 // Offset of the symbol in the section
1586 int64_t a = Layout.getSymbolAddress(&SDB) - Layout.getSectionAddress(Sec);
1588 // Ofeset of the relocation in the section
1589 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
1594 MCSymbolData &SD = Asm.getSymbolData(ASymbol);
1595 MCFragment *F = SD.getFragment();
1597 Index = F->getParent()->getOrdinal() + 1;
1599 MCSectionData *FSD = F->getParent();
1600 // Offset of the symbol in the section
1601 Value += Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD);
1603 if (Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
1604 WeakrefUsedInReloc.insert(RelocSymbol);
1606 UsedInReloc.insert(RelocSymbol);
1610 // Compensate for the addend on i386.
1617 // determine the type of the relocation
1619 MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
1620 MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
1626 llvm_unreachable("Unimplemented");
1627 case MCSymbolRefExpr::VK_None:
1628 Type = ELF::R_X86_64_PC32;
1630 case MCSymbolRefExpr::VK_PLT:
1631 Type = ELF::R_X86_64_PLT32;
1633 case MCSymbolRefExpr::VK_GOTPCREL:
1634 Type = ELF::R_X86_64_GOTPCREL;
1636 case MCSymbolRefExpr::VK_GOTTPOFF:
1637 Type = ELF::R_X86_64_GOTTPOFF;
1639 case MCSymbolRefExpr::VK_TLSGD:
1640 Type = ELF::R_X86_64_TLSGD;
1642 case MCSymbolRefExpr::VK_TLSLD:
1643 Type = ELF::R_X86_64_TLSLD;
1647 switch ((unsigned)Fixup.getKind()) {
1648 default: llvm_unreachable("invalid fixup kind!");
1649 case FK_Data_8: Type = ELF::R_X86_64_64; break;
1650 case X86::reloc_signed_4byte:
1652 assert(isInt<32>(Target.getConstant()));
1655 llvm_unreachable("Unimplemented");
1656 case MCSymbolRefExpr::VK_None:
1657 Type = ELF::R_X86_64_32S;
1659 case MCSymbolRefExpr::VK_GOT:
1660 Type = ELF::R_X86_64_GOT32;
1662 case MCSymbolRefExpr::VK_GOTPCREL:
1663 Type = ELF::R_X86_64_GOTPCREL;
1665 case MCSymbolRefExpr::VK_TPOFF:
1666 Type = ELF::R_X86_64_TPOFF32;
1668 case MCSymbolRefExpr::VK_DTPOFF:
1669 Type = ELF::R_X86_64_DTPOFF32;
1674 Type = ELF::R_X86_64_32;
1676 case FK_Data_2: Type = ELF::R_X86_64_16; break;
1678 case FK_Data_1: Type = ELF::R_X86_64_8; break;
1685 llvm_unreachable("Unimplemented");
1686 case MCSymbolRefExpr::VK_None:
1687 Type = ELF::R_386_PC32;
1689 case MCSymbolRefExpr::VK_PLT:
1690 Type = ELF::R_386_PLT32;
1694 switch ((unsigned)Fixup.getKind()) {
1695 default: llvm_unreachable("invalid fixup kind!");
1697 case X86::reloc_global_offset_table:
1698 Type = ELF::R_386_GOTPC;
1701 // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode
1703 case X86::reloc_signed_4byte:
1708 llvm_unreachable("Unimplemented");
1709 case MCSymbolRefExpr::VK_None:
1710 Type = ELF::R_386_32;
1712 case MCSymbolRefExpr::VK_GOT:
1713 Type = ELF::R_386_GOT32;
1715 case MCSymbolRefExpr::VK_GOTOFF:
1716 Type = ELF::R_386_GOTOFF;
1718 case MCSymbolRefExpr::VK_TLSGD:
1719 Type = ELF::R_386_TLS_GD;
1721 case MCSymbolRefExpr::VK_TPOFF:
1722 Type = ELF::R_386_TLS_LE_32;
1724 case MCSymbolRefExpr::VK_INDNTPOFF:
1725 Type = ELF::R_386_TLS_IE;
1727 case MCSymbolRefExpr::VK_NTPOFF:
1728 Type = ELF::R_386_TLS_LE;
1730 case MCSymbolRefExpr::VK_GOTNTPOFF:
1731 Type = ELF::R_386_TLS_GOTIE;
1733 case MCSymbolRefExpr::VK_TLSLDM:
1734 Type = ELF::R_386_TLS_LDM;
1736 case MCSymbolRefExpr::VK_DTPOFF:
1737 Type = ELF::R_386_TLS_LDO_32;
1741 case FK_Data_2: Type = ELF::R_386_16; break;
1743 case FK_Data_1: Type = ELF::R_386_8; break;
1748 if (RelocNeedsGOT(Modifier))
1752 uint64_t RelocOffset = Layout.getFragmentOffset(Fragment) +
1755 if (!HasRelocationAddend) Addend = 0;
1756 ELFRelocationEntry ERE(RelocOffset, Index, Type, RelocSymbol, Addend);
1757 Relocations[Fragment->getParent()].push_back(ERE);