1 //===-- llvm/MC/WinCOFFObjectWriter.cpp -------------------------*- C++ -*-===//
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 contains an implementation of a Win32 COFF object file writer.
12 //===----------------------------------------------------------------------===//
14 #define DEBUG_TYPE "WinCOFFObjectWriter"
16 #include "llvm/MC/MCWinCOFFObjectWriter.h"
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/OwningPtr.h"
19 #include "llvm/ADT/StringMap.h"
20 #include "llvm/ADT/StringRef.h"
21 #include "llvm/ADT/Twine.h"
22 #include "llvm/MC/MCAsmLayout.h"
23 #include "llvm/MC/MCAssembler.h"
24 #include "llvm/MC/MCContext.h"
25 #include "llvm/MC/MCExpr.h"
26 #include "llvm/MC/MCObjectWriter.h"
27 #include "llvm/MC/MCSection.h"
28 #include "llvm/MC/MCSectionCOFF.h"
29 #include "llvm/MC/MCSymbol.h"
30 #include "llvm/MC/MCValue.h"
31 #include "llvm/Support/COFF.h"
32 #include "llvm/Support/Debug.h"
33 #include "llvm/Support/ErrorHandling.h"
34 #include "llvm/Support/TimeValue.h"
40 typedef SmallString<COFF::NameSize> name;
51 AuxiliaryType AuxType;
62 typedef SmallVector<AuxSymbol, 1> AuxiliarySymbols;
71 MCSymbolData const *MCData;
73 COFFSymbol(StringRef name);
75 void set_name_offset(uint32_t Offset);
77 bool should_keep() const;
80 // This class contains staging data for a COFF relocation entry.
81 struct COFFRelocation {
82 COFF::relocation Data;
85 COFFRelocation() : Symb(NULL) {}
86 static size_t size() { return COFF::RelocationSize; }
89 typedef std::vector<COFFRelocation> relocations;
97 MCSectionData const *MCData;
99 relocations Relocations;
101 COFFSection(StringRef name);
102 static size_t size();
105 // This class holds the COFF string table.
107 typedef StringMap<size_t> map;
110 void update_length();
112 std::vector<char> Data;
116 size_t insert(StringRef String);
119 class WinCOFFObjectWriter : public MCObjectWriter {
122 typedef std::vector<COFFSymbol*> symbols;
123 typedef std::vector<COFFSection*> sections;
125 typedef DenseMap<MCSymbol const *, COFFSymbol *> symbol_map;
126 typedef DenseMap<MCSection const *, COFFSection *> section_map;
128 llvm::OwningPtr<MCWinCOFFObjectTargetWriter> TargetObjectWriter;
130 // Root level file contents.
136 // Maps used during object file creation.
137 section_map SectionMap;
138 symbol_map SymbolMap;
140 WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW, raw_ostream &OS);
141 ~WinCOFFObjectWriter();
143 COFFSymbol *createSymbol(StringRef Name);
144 COFFSymbol *GetOrCreateCOFFSymbol(const MCSymbol * Symbol);
145 COFFSection *createSection(StringRef Name);
147 template <typename object_t, typename list_t>
148 object_t *createCOFFEntity(StringRef Name, list_t &List);
150 void DefineSection(MCSectionData const &SectionData);
151 void DefineSymbol(MCSymbolData const &SymbolData,
152 MCAssembler &Assembler);
154 void MakeSymbolReal(COFFSymbol &S, size_t Index);
155 void MakeSectionReal(COFFSection &S, size_t Number);
157 bool ExportSymbol(MCSymbolData const &SymbolData, MCAssembler &Asm);
159 bool IsPhysicalSection(COFFSection *S);
161 // Entity writing methods.
163 void WriteFileHeader(const COFF::header &Header);
164 void WriteSymbol(const COFFSymbol *S);
165 void WriteAuxiliarySymbols(const COFFSymbol::AuxiliarySymbols &S);
166 void WriteSectionHeader(const COFF::section &S);
167 void WriteRelocation(const COFF::relocation &R);
169 // MCObjectWriter interface implementation.
171 void ExecutePostLayoutBinding(MCAssembler &Asm, const MCAsmLayout &Layout);
173 void RecordRelocation(const MCAssembler &Asm,
174 const MCAsmLayout &Layout,
175 const MCFragment *Fragment,
176 const MCFixup &Fixup,
178 uint64_t &FixedValue);
180 void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
184 static inline void write_uint32_le(void *Data, uint32_t const &Value) {
185 uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
186 Ptr[0] = (Value & 0x000000FF) >> 0;
187 Ptr[1] = (Value & 0x0000FF00) >> 8;
188 Ptr[2] = (Value & 0x00FF0000) >> 16;
189 Ptr[3] = (Value & 0xFF000000) >> 24;
192 //------------------------------------------------------------------------------
193 // Symbol class implementation
195 COFFSymbol::COFFSymbol(StringRef name)
196 : Name(name.begin(), name.end())
201 memset(&Data, 0, sizeof(Data));
204 size_t COFFSymbol::size() const {
205 return COFF::SymbolSize + (Data.NumberOfAuxSymbols * COFF::SymbolSize);
208 // In the case that the name does not fit within 8 bytes, the offset
209 // into the string table is stored in the last 4 bytes instead, leaving
210 // the first 4 bytes as 0.
211 void COFFSymbol::set_name_offset(uint32_t Offset) {
212 write_uint32_le(Data.Name + 0, 0);
213 write_uint32_le(Data.Name + 4, Offset);
216 /// logic to decide if the symbol should be reported in the symbol table
217 bool COFFSymbol::should_keep() const {
218 // no section means its external, keep it
222 // if it has relocations pointing at it, keep it
223 if (Relocations > 0) {
224 assert(Section->Number != -1 && "Sections with relocations must be real!");
228 // if the section its in is being droped, drop it
229 if (Section->Number == -1)
232 // if it is the section symbol, keep it
233 if (Section->Symbol == this)
236 // if its temporary, drop it
237 if (MCData && MCData->getSymbol().isTemporary())
240 // otherwise, keep it
244 //------------------------------------------------------------------------------
245 // Section class implementation
247 COFFSection::COFFSection(StringRef name)
251 memset(&Header, 0, sizeof(Header));
254 size_t COFFSection::size() {
255 return COFF::SectionSize;
258 //------------------------------------------------------------------------------
259 // StringTable class implementation
261 /// Write the length of the string table into Data.
262 /// The length of the string table includes uint32 length header.
263 void StringTable::update_length() {
264 write_uint32_le(&Data.front(), Data.size());
267 StringTable::StringTable() {
268 // The string table data begins with the length of the entire string table
269 // including the length header. Allocate space for this header.
274 size_t StringTable::size() const {
278 /// Add String to the table iff it is not already there.
279 /// @returns the index into the string table where the string is now located.
280 size_t StringTable::insert(StringRef String) {
281 map::iterator i = Map.find(String);
286 size_t Offset = Data.size();
288 // Insert string data into string table.
289 Data.insert(Data.end(), String.begin(), String.end());
290 Data.push_back('\0');
292 // Put a reference to it in the map.
293 Map[String] = Offset;
295 // Update the internal length field.
301 //------------------------------------------------------------------------------
302 // WinCOFFObjectWriter class implementation
304 WinCOFFObjectWriter::WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
306 : MCObjectWriter(OS, true)
307 , TargetObjectWriter(MOTW) {
308 memset(&Header, 0, sizeof(Header));
310 Header.Machine = TargetObjectWriter->getMachine();
313 WinCOFFObjectWriter::~WinCOFFObjectWriter() {
314 for (symbols::iterator I = Symbols.begin(), E = Symbols.end(); I != E; ++I)
316 for (sections::iterator I = Sections.begin(), E = Sections.end(); I != E; ++I)
320 COFFSymbol *WinCOFFObjectWriter::createSymbol(StringRef Name) {
321 return createCOFFEntity<COFFSymbol>(Name, Symbols);
324 COFFSymbol *WinCOFFObjectWriter::GetOrCreateCOFFSymbol(const MCSymbol * Symbol){
325 symbol_map::iterator i = SymbolMap.find(Symbol);
326 if (i != SymbolMap.end())
328 COFFSymbol *RetSymbol
329 = createCOFFEntity<COFFSymbol>(Symbol->getName(), Symbols);
330 SymbolMap[Symbol] = RetSymbol;
334 COFFSection *WinCOFFObjectWriter::createSection(StringRef Name) {
335 return createCOFFEntity<COFFSection>(Name, Sections);
338 /// A template used to lookup or create a symbol/section, and initialize it if
340 template <typename object_t, typename list_t>
341 object_t *WinCOFFObjectWriter::createCOFFEntity(StringRef Name,
343 object_t *Object = new object_t(Name);
345 List.push_back(Object);
350 /// This function takes a section data object from the assembler
351 /// and creates the associated COFF section staging object.
352 void WinCOFFObjectWriter::DefineSection(MCSectionData const &SectionData) {
353 assert(SectionData.getSection().getVariant() == MCSection::SV_COFF
354 && "Got non COFF section in the COFF backend!");
355 // FIXME: Not sure how to verify this (at least in a debug build).
356 MCSectionCOFF const &Sec =
357 static_cast<MCSectionCOFF const &>(SectionData.getSection());
359 COFFSection *coff_section = createSection(Sec.getSectionName());
360 COFFSymbol *coff_symbol = createSymbol(Sec.getSectionName());
362 coff_section->Symbol = coff_symbol;
363 coff_symbol->Section = coff_section;
364 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC;
366 // In this case the auxiliary symbol is a Section Definition.
367 coff_symbol->Aux.resize(1);
368 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
369 coff_symbol->Aux[0].AuxType = ATSectionDefinition;
370 coff_symbol->Aux[0].Aux.SectionDefinition.Selection = Sec.getSelection();
372 coff_section->Header.Characteristics = Sec.getCharacteristics();
374 uint32_t &Characteristics = coff_section->Header.Characteristics;
375 switch (SectionData.getAlignment()) {
376 case 1: Characteristics |= COFF::IMAGE_SCN_ALIGN_1BYTES; break;
377 case 2: Characteristics |= COFF::IMAGE_SCN_ALIGN_2BYTES; break;
378 case 4: Characteristics |= COFF::IMAGE_SCN_ALIGN_4BYTES; break;
379 case 8: Characteristics |= COFF::IMAGE_SCN_ALIGN_8BYTES; break;
380 case 16: Characteristics |= COFF::IMAGE_SCN_ALIGN_16BYTES; break;
381 case 32: Characteristics |= COFF::IMAGE_SCN_ALIGN_32BYTES; break;
382 case 64: Characteristics |= COFF::IMAGE_SCN_ALIGN_64BYTES; break;
383 case 128: Characteristics |= COFF::IMAGE_SCN_ALIGN_128BYTES; break;
384 case 256: Characteristics |= COFF::IMAGE_SCN_ALIGN_256BYTES; break;
385 case 512: Characteristics |= COFF::IMAGE_SCN_ALIGN_512BYTES; break;
386 case 1024: Characteristics |= COFF::IMAGE_SCN_ALIGN_1024BYTES; break;
387 case 2048: Characteristics |= COFF::IMAGE_SCN_ALIGN_2048BYTES; break;
388 case 4096: Characteristics |= COFF::IMAGE_SCN_ALIGN_4096BYTES; break;
389 case 8192: Characteristics |= COFF::IMAGE_SCN_ALIGN_8192BYTES; break;
391 llvm_unreachable("unsupported section alignment");
394 // Bind internal COFF section to MC section.
395 coff_section->MCData = &SectionData;
396 SectionMap[&SectionData.getSection()] = coff_section;
399 /// This function takes a section data object from the assembler
400 /// and creates the associated COFF symbol staging object.
401 void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
402 MCAssembler &Assembler) {
403 MCSymbol const &Symbol = SymbolData.getSymbol();
404 COFFSymbol *coff_symbol = GetOrCreateCOFFSymbol(&Symbol);
405 SymbolMap[&Symbol] = coff_symbol;
407 if (SymbolData.getFlags() & COFF::SF_WeakExternal) {
408 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
410 if (Symbol.isVariable()) {
411 const MCSymbolRefExpr *SymRef =
412 dyn_cast<MCSymbolRefExpr>(Symbol.getVariableValue());
415 report_fatal_error("Weak externals may only alias symbols");
417 coff_symbol->Other = GetOrCreateCOFFSymbol(&SymRef->getSymbol());
419 std::string WeakName = std::string(".weak.")
420 + Symbol.getName().str()
422 COFFSymbol *WeakDefault = createSymbol(WeakName);
423 WeakDefault->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
424 WeakDefault->Data.StorageClass = COFF::IMAGE_SYM_CLASS_EXTERNAL;
425 WeakDefault->Data.Type = 0;
426 WeakDefault->Data.Value = 0;
427 coff_symbol->Other = WeakDefault;
430 // Setup the Weak External auxiliary symbol.
431 coff_symbol->Aux.resize(1);
432 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
433 coff_symbol->Aux[0].AuxType = ATWeakExternal;
434 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = 0;
435 coff_symbol->Aux[0].Aux.WeakExternal.Characteristics =
436 COFF::IMAGE_WEAK_EXTERN_SEARCH_LIBRARY;
438 coff_symbol->MCData = &SymbolData;
440 const MCSymbolData &ResSymData =
441 Assembler.getSymbolData(Symbol.AliasedSymbol());
443 coff_symbol->Data.Type = (ResSymData.getFlags() & 0x0000FFFF) >> 0;
444 coff_symbol->Data.StorageClass = (ResSymData.getFlags() & 0x00FF0000) >> 16;
446 // If no storage class was specified in the streamer, define it here.
447 if (coff_symbol->Data.StorageClass == 0) {
448 bool external = ResSymData.isExternal() || (ResSymData.Fragment == NULL);
450 coff_symbol->Data.StorageClass =
451 external ? COFF::IMAGE_SYM_CLASS_EXTERNAL : COFF::IMAGE_SYM_CLASS_STATIC;
454 if (ResSymData.Fragment != NULL)
455 coff_symbol->Section =
456 SectionMap[&ResSymData.Fragment->getParent()->getSection()];
458 coff_symbol->MCData = &ResSymData;
462 /// making a section real involves assigned it a number and putting
463 /// name into the string table if needed
464 void WinCOFFObjectWriter::MakeSectionReal(COFFSection &S, size_t Number) {
465 if (S.Name.size() > COFF::NameSize) {
466 const unsigned Max6DecimalSize = 999999;
467 const unsigned Max7DecimalSize = 9999999;
468 uint64_t StringTableEntry = Strings.insert(S.Name.c_str());
470 if (StringTableEntry <= Max6DecimalSize) {
471 std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry));
472 } else if (StringTableEntry <= Max7DecimalSize) {
473 // With seven digits, we have to skip the terminating null. Because
474 // sprintf always appends it, we use a larger temporary buffer.
475 char buffer[9] = { };
476 std::sprintf(buffer, "/%d", unsigned(StringTableEntry));
477 std::memcpy(S.Header.Name, buffer, 8);
479 report_fatal_error("COFF string table is greater than 9,999,999 bytes.");
482 std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size());
485 S.Symbol->Data.SectionNumber = S.Number;
486 S.Symbol->Aux[0].Aux.SectionDefinition.Number = S.Number;
489 void WinCOFFObjectWriter::MakeSymbolReal(COFFSymbol &S, size_t Index) {
490 if (S.Name.size() > COFF::NameSize) {
491 size_t StringTableEntry = Strings.insert(S.Name.c_str());
493 S.set_name_offset(StringTableEntry);
495 std::memcpy(S.Data.Name, S.Name.c_str(), S.Name.size());
499 bool WinCOFFObjectWriter::ExportSymbol(MCSymbolData const &SymbolData,
501 // This doesn't seem to be right. Strings referred to from the .data section
502 // need symbols so they can be linked to code in the .text section right?
504 // return Asm.isSymbolLinkerVisible (&SymbolData);
506 // For now, all non-variable symbols are exported,
507 // the linker will sort the rest out for us.
508 return SymbolData.isExternal() || !SymbolData.getSymbol().isVariable();
511 bool WinCOFFObjectWriter::IsPhysicalSection(COFFSection *S) {
512 return (S->Header.Characteristics
513 & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0;
516 //------------------------------------------------------------------------------
517 // entity writing methods
519 void WinCOFFObjectWriter::WriteFileHeader(const COFF::header &Header) {
520 WriteLE16(Header.Machine);
521 WriteLE16(Header.NumberOfSections);
522 WriteLE32(Header.TimeDateStamp);
523 WriteLE32(Header.PointerToSymbolTable);
524 WriteLE32(Header.NumberOfSymbols);
525 WriteLE16(Header.SizeOfOptionalHeader);
526 WriteLE16(Header.Characteristics);
529 void WinCOFFObjectWriter::WriteSymbol(const COFFSymbol *S) {
530 WriteBytes(StringRef(S->Data.Name, COFF::NameSize));
531 WriteLE32(S->Data.Value);
532 WriteLE16(S->Data.SectionNumber);
533 WriteLE16(S->Data.Type);
534 Write8(S->Data.StorageClass);
535 Write8(S->Data.NumberOfAuxSymbols);
536 WriteAuxiliarySymbols(S->Aux);
539 void WinCOFFObjectWriter::WriteAuxiliarySymbols(
540 const COFFSymbol::AuxiliarySymbols &S) {
541 for(COFFSymbol::AuxiliarySymbols::const_iterator i = S.begin(), e = S.end();
544 case ATFunctionDefinition:
545 WriteLE32(i->Aux.FunctionDefinition.TagIndex);
546 WriteLE32(i->Aux.FunctionDefinition.TotalSize);
547 WriteLE32(i->Aux.FunctionDefinition.PointerToLinenumber);
548 WriteLE32(i->Aux.FunctionDefinition.PointerToNextFunction);
549 WriteZeros(sizeof(i->Aux.FunctionDefinition.unused));
551 case ATbfAndefSymbol:
552 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused1));
553 WriteLE16(i->Aux.bfAndefSymbol.Linenumber);
554 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused2));
555 WriteLE32(i->Aux.bfAndefSymbol.PointerToNextFunction);
556 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused3));
559 WriteLE32(i->Aux.WeakExternal.TagIndex);
560 WriteLE32(i->Aux.WeakExternal.Characteristics);
561 WriteZeros(sizeof(i->Aux.WeakExternal.unused));
564 WriteBytes(StringRef(reinterpret_cast<const char *>(i->Aux.File.FileName),
565 sizeof(i->Aux.File.FileName)));
567 case ATSectionDefinition:
568 WriteLE32(i->Aux.SectionDefinition.Length);
569 WriteLE16(i->Aux.SectionDefinition.NumberOfRelocations);
570 WriteLE16(i->Aux.SectionDefinition.NumberOfLinenumbers);
571 WriteLE32(i->Aux.SectionDefinition.CheckSum);
572 WriteLE16(i->Aux.SectionDefinition.Number);
573 Write8(i->Aux.SectionDefinition.Selection);
574 WriteZeros(sizeof(i->Aux.SectionDefinition.unused));
580 void WinCOFFObjectWriter::WriteSectionHeader(const COFF::section &S) {
581 WriteBytes(StringRef(S.Name, COFF::NameSize));
583 WriteLE32(S.VirtualSize);
584 WriteLE32(S.VirtualAddress);
585 WriteLE32(S.SizeOfRawData);
586 WriteLE32(S.PointerToRawData);
587 WriteLE32(S.PointerToRelocations);
588 WriteLE32(S.PointerToLineNumbers);
589 WriteLE16(S.NumberOfRelocations);
590 WriteLE16(S.NumberOfLineNumbers);
591 WriteLE32(S.Characteristics);
594 void WinCOFFObjectWriter::WriteRelocation(const COFF::relocation &R) {
595 WriteLE32(R.VirtualAddress);
596 WriteLE32(R.SymbolTableIndex);
600 ////////////////////////////////////////////////////////////////////////////////
601 // MCObjectWriter interface implementations
603 void WinCOFFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
604 const MCAsmLayout &Layout) {
605 // "Define" each section & symbol. This creates section & symbol
606 // entries in the staging area.
608 for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e; i++)
611 for (MCAssembler::const_symbol_iterator i = Asm.symbol_begin(),
612 e = Asm.symbol_end(); i != e; i++) {
613 if (ExportSymbol(*i, Asm)) {
614 DefineSymbol(*i, Asm);
619 void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
620 const MCAsmLayout &Layout,
621 const MCFragment *Fragment,
622 const MCFixup &Fixup,
624 uint64_t &FixedValue) {
625 assert(Target.getSymA() != NULL && "Relocation must reference a symbol!");
627 const MCSymbol &Symbol = Target.getSymA()->getSymbol();
628 const MCSymbol &A = Symbol.AliasedSymbol();
629 MCSymbolData &A_SD = Asm.getSymbolData(A);
631 MCSectionData const *SectionData = Fragment->getParent();
633 // Mark this symbol as requiring an entry in the symbol table.
634 assert(SectionMap.find(&SectionData->getSection()) != SectionMap.end() &&
635 "Section must already have been defined in ExecutePostLayoutBinding!");
636 assert(SymbolMap.find(&A_SD.getSymbol()) != SymbolMap.end() &&
637 "Symbol must already have been defined in ExecutePostLayoutBinding!");
639 COFFSection *coff_section = SectionMap[&SectionData->getSection()];
640 COFFSymbol *coff_symbol = SymbolMap[&A_SD.getSymbol()];
641 const MCSymbolRefExpr *SymA = Target.getSymA();
642 const MCSymbolRefExpr *SymB = Target.getSymB();
643 const bool CrossSection = SymB &&
644 &SymA->getSymbol().getSection() != &SymB->getSymbol().getSection();
646 if (Target.getSymB()) {
647 const MCSymbol *B = &Target.getSymB()->getSymbol();
648 MCSymbolData &B_SD = Asm.getSymbolData(*B);
650 // Offset of the symbol in the section
651 int64_t a = Layout.getSymbolOffset(&B_SD);
653 // Ofeset of the relocation in the section
654 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
657 // In the case where we have SymbA and SymB, we just need to store the delta
658 // between the two symbols. Update FixedValue to account for the delta, and
659 // skip recording the relocation.
663 FixedValue = Target.getConstant();
666 COFFRelocation Reloc;
668 Reloc.Data.SymbolTableIndex = 0;
669 Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
671 // Turn relocations for temporary symbols into section relocations.
672 if (coff_symbol->MCData->getSymbol().isTemporary() || CrossSection) {
673 Reloc.Symb = coff_symbol->Section->Symbol;
674 FixedValue += Layout.getFragmentOffset(coff_symbol->MCData->Fragment)
675 + coff_symbol->MCData->getOffset();
677 Reloc.Symb = coff_symbol;
679 ++Reloc.Symb->Relocations;
681 Reloc.Data.VirtualAddress += Fixup.getOffset();
682 Reloc.Data.Type = TargetObjectWriter->getRelocType(Target, Fixup,
685 // FIXME: Can anyone explain what this does other than adjust for the size
687 if (Reloc.Data.Type == COFF::IMAGE_REL_AMD64_REL32 ||
688 Reloc.Data.Type == COFF::IMAGE_REL_I386_REL32)
691 coff_section->Relocations.push_back(Reloc);
694 void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
695 const MCAsmLayout &Layout) {
696 // Assign symbol and section indexes and offsets.
697 Header.NumberOfSections = 0;
699 DenseMap<COFFSection *, uint16_t> SectionIndices;
700 for (sections::iterator i = Sections.begin(),
701 e = Sections.end(); i != e; i++) {
702 if (Layout.getSectionAddressSize((*i)->MCData) > 0) {
703 size_t Number = ++Header.NumberOfSections;
704 SectionIndices[*i] = Number;
705 MakeSectionReal(**i, Number);
711 Header.NumberOfSymbols = 0;
713 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
714 COFFSymbol *coff_symbol = *i;
715 MCSymbolData const *SymbolData = coff_symbol->MCData;
717 // Update section number & offset for symbols that have them.
718 if ((SymbolData != NULL) && (SymbolData->Fragment != NULL)) {
719 assert(coff_symbol->Section != NULL);
721 coff_symbol->Data.SectionNumber = coff_symbol->Section->Number;
722 coff_symbol->Data.Value = Layout.getFragmentOffset(SymbolData->Fragment)
723 + SymbolData->Offset;
726 if (coff_symbol->should_keep()) {
727 MakeSymbolReal(*coff_symbol, Header.NumberOfSymbols++);
729 // Update auxiliary symbol info.
730 coff_symbol->Data.NumberOfAuxSymbols = coff_symbol->Aux.size();
731 Header.NumberOfSymbols += coff_symbol->Data.NumberOfAuxSymbols;
733 coff_symbol->Index = -1;
736 // Fixup weak external references.
737 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
738 COFFSymbol *coff_symbol = *i;
739 if (coff_symbol->Other != NULL) {
740 assert(coff_symbol->Index != -1);
741 assert(coff_symbol->Aux.size() == 1 &&
742 "Symbol must contain one aux symbol!");
743 assert(coff_symbol->Aux[0].AuxType == ATWeakExternal &&
744 "Symbol's aux symbol must be a Weak External!");
745 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = coff_symbol->Other->Index;
749 // Fixup associative COMDAT sections.
750 for (sections::iterator i = Sections.begin(),
751 e = Sections.end(); i != e; i++) {
752 if ((*i)->Symbol->Aux[0].Aux.SectionDefinition.Selection !=
753 COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE)
756 const MCSectionCOFF &MCSec = static_cast<const MCSectionCOFF &>(
757 (*i)->MCData->getSection());
759 COFFSection *Assoc = SectionMap.lookup(MCSec.getAssocSection());
761 report_fatal_error(Twine("Missing associated COMDAT section ") +
762 MCSec.getAssocSection()->getSectionName() +
763 " for section " + MCSec.getSectionName());
766 // Skip this section if the associated section is unused.
767 if (Assoc->Number == -1)
770 (*i)->Symbol->Aux[0].Aux.SectionDefinition.Number = SectionIndices[Assoc];
774 // Assign file offsets to COFF object file structures.
778 offset += COFF::HeaderSize;
779 offset += COFF::SectionSize * Header.NumberOfSections;
781 for (MCAssembler::const_iterator i = Asm.begin(),
784 COFFSection *Sec = SectionMap[&i->getSection()];
786 if (Sec->Number == -1)
789 Sec->Header.SizeOfRawData = Layout.getSectionAddressSize(i);
791 if (IsPhysicalSection(Sec)) {
792 Sec->Header.PointerToRawData = offset;
794 offset += Sec->Header.SizeOfRawData;
797 if (Sec->Relocations.size() > 0) {
798 bool RelocationsOverflow = Sec->Relocations.size() >= 0xffff;
800 if (RelocationsOverflow) {
801 // Signal overflow by setting NumberOfSections to max value. Actual
802 // size is found in reloc #0. Microsoft tools understand this.
803 Sec->Header.NumberOfRelocations = 0xffff;
805 Sec->Header.NumberOfRelocations = Sec->Relocations.size();
807 Sec->Header.PointerToRelocations = offset;
809 if (RelocationsOverflow) {
810 // Reloc #0 will contain actual count, so make room for it.
811 offset += COFF::RelocationSize;
814 offset += COFF::RelocationSize * Sec->Relocations.size();
816 for (relocations::iterator cr = Sec->Relocations.begin(),
817 er = Sec->Relocations.end();
819 assert((*cr).Symb->Index != -1);
820 (*cr).Data.SymbolTableIndex = (*cr).Symb->Index;
824 assert(Sec->Symbol->Aux.size() == 1
825 && "Section's symbol must have one aux!");
826 AuxSymbol &Aux = Sec->Symbol->Aux[0];
827 assert(Aux.AuxType == ATSectionDefinition &&
828 "Section's symbol's aux symbol must be a Section Definition!");
829 Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData;
830 Aux.Aux.SectionDefinition.NumberOfRelocations =
831 Sec->Header.NumberOfRelocations;
832 Aux.Aux.SectionDefinition.NumberOfLinenumbers =
833 Sec->Header.NumberOfLineNumbers;
836 Header.PointerToSymbolTable = offset;
838 Header.TimeDateStamp = sys::TimeValue::now().toEpochTime();
840 // Write it all to disk...
841 WriteFileHeader(Header);
844 sections::iterator i, ie;
845 MCAssembler::const_iterator j, je;
847 for (i = Sections.begin(), ie = Sections.end(); i != ie; i++)
848 if ((*i)->Number != -1) {
849 if ((*i)->Relocations.size() >= 0xffff) {
850 (*i)->Header.Characteristics |= COFF::IMAGE_SCN_LNK_NRELOC_OVFL;
852 WriteSectionHeader((*i)->Header);
855 for (i = Sections.begin(), ie = Sections.end(),
856 j = Asm.begin(), je = Asm.end();
857 (i != ie) && (j != je); ++i, ++j) {
859 if ((*i)->Number == -1)
862 if ((*i)->Header.PointerToRawData != 0) {
863 assert(OS.tell() == (*i)->Header.PointerToRawData &&
864 "Section::PointerToRawData is insane!");
866 Asm.writeSectionData(j, Layout);
869 if ((*i)->Relocations.size() > 0) {
870 assert(OS.tell() == (*i)->Header.PointerToRelocations &&
871 "Section::PointerToRelocations is insane!");
873 if ((*i)->Relocations.size() >= 0xffff) {
874 // In case of overflow, write actual relocation count as first
875 // relocation. Including the synthetic reloc itself (+ 1).
877 r.VirtualAddress = (*i)->Relocations.size() + 1;
878 r.SymbolTableIndex = 0;
883 for (relocations::const_iterator k = (*i)->Relocations.begin(),
884 ke = (*i)->Relocations.end();
886 WriteRelocation(k->Data);
889 assert((*i)->Header.PointerToRelocations == 0 &&
890 "Section::PointerToRelocations is insane!");
894 assert(OS.tell() == Header.PointerToSymbolTable &&
895 "Header::PointerToSymbolTable is insane!");
897 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++)
898 if ((*i)->Index != -1)
901 OS.write((char const *)&Strings.Data.front(), Strings.Data.size());
904 MCWinCOFFObjectTargetWriter::MCWinCOFFObjectTargetWriter(unsigned Machine_) :
908 //------------------------------------------------------------------------------
909 // WinCOFFObjectWriter factory function
912 MCObjectWriter *createWinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
914 return new WinCOFFObjectWriter(MOTW, OS);