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 ExportSection(COFFSection const *S);
158 bool ExportSymbol(MCSymbolData const &SymbolData, MCAssembler &Asm);
160 bool IsPhysicalSection(COFFSection *S);
162 // Entity writing methods.
164 void WriteFileHeader(const COFF::header &Header);
165 void WriteSymbol(const COFFSymbol *S);
166 void WriteAuxiliarySymbols(const COFFSymbol::AuxiliarySymbols &S);
167 void WriteSectionHeader(const COFF::section &S);
168 void WriteRelocation(const COFF::relocation &R);
170 // MCObjectWriter interface implementation.
172 void ExecutePostLayoutBinding(MCAssembler &Asm, const MCAsmLayout &Layout);
174 void RecordRelocation(const MCAssembler &Asm,
175 const MCAsmLayout &Layout,
176 const MCFragment *Fragment,
177 const MCFixup &Fixup,
179 uint64_t &FixedValue);
181 void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
185 static inline void write_uint32_le(void *Data, uint32_t const &Value) {
186 uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
187 Ptr[0] = (Value & 0x000000FF) >> 0;
188 Ptr[1] = (Value & 0x0000FF00) >> 8;
189 Ptr[2] = (Value & 0x00FF0000) >> 16;
190 Ptr[3] = (Value & 0xFF000000) >> 24;
193 //------------------------------------------------------------------------------
194 // Symbol class implementation
196 COFFSymbol::COFFSymbol(StringRef name)
197 : Name(name.begin(), name.end())
202 memset(&Data, 0, sizeof(Data));
205 size_t COFFSymbol::size() const {
206 return COFF::SymbolSize + (Data.NumberOfAuxSymbols * COFF::SymbolSize);
209 // In the case that the name does not fit within 8 bytes, the offset
210 // into the string table is stored in the last 4 bytes instead, leaving
211 // the first 4 bytes as 0.
212 void COFFSymbol::set_name_offset(uint32_t Offset) {
213 write_uint32_le(Data.Name + 0, 0);
214 write_uint32_le(Data.Name + 4, Offset);
217 /// logic to decide if the symbol should be reported in the symbol table
218 bool COFFSymbol::should_keep() const {
219 // no section means its external, keep it
223 // if it has relocations pointing at it, keep it
224 if (Relocations > 0) {
225 assert(Section->Number != -1 && "Sections with relocations must be real!");
229 // if the section its in is being droped, drop it
230 if (Section->Number == -1)
233 // if it is the section symbol, keep it
234 if (Section->Symbol == this)
237 // if its temporary, drop it
238 if (MCData && MCData->getSymbol().isTemporary())
241 // otherwise, keep it
245 //------------------------------------------------------------------------------
246 // Section class implementation
248 COFFSection::COFFSection(StringRef name)
252 memset(&Header, 0, sizeof(Header));
255 size_t COFFSection::size() {
256 return COFF::SectionSize;
259 //------------------------------------------------------------------------------
260 // StringTable class implementation
262 /// Write the length of the string table into Data.
263 /// The length of the string table includes uint32 length header.
264 void StringTable::update_length() {
265 write_uint32_le(&Data.front(), Data.size());
268 StringTable::StringTable() {
269 // The string table data begins with the length of the entire string table
270 // including the length header. Allocate space for this header.
275 size_t StringTable::size() const {
279 /// Add String to the table iff it is not already there.
280 /// @returns the index into the string table where the string is now located.
281 size_t StringTable::insert(StringRef String) {
282 map::iterator i = Map.find(String);
287 size_t Offset = Data.size();
289 // Insert string data into string table.
290 Data.insert(Data.end(), String.begin(), String.end());
291 Data.push_back('\0');
293 // Put a reference to it in the map.
294 Map[String] = Offset;
296 // Update the internal length field.
302 //------------------------------------------------------------------------------
303 // WinCOFFObjectWriter class implementation
305 WinCOFFObjectWriter::WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
307 : MCObjectWriter(OS, true)
308 , TargetObjectWriter(MOTW) {
309 memset(&Header, 0, sizeof(Header));
311 Header.Machine = TargetObjectWriter->getMachine();
314 WinCOFFObjectWriter::~WinCOFFObjectWriter() {
315 for (symbols::iterator I = Symbols.begin(), E = Symbols.end(); I != E; ++I)
317 for (sections::iterator I = Sections.begin(), E = Sections.end(); I != E; ++I)
321 COFFSymbol *WinCOFFObjectWriter::createSymbol(StringRef Name) {
322 return createCOFFEntity<COFFSymbol>(Name, Symbols);
325 COFFSymbol *WinCOFFObjectWriter::GetOrCreateCOFFSymbol(const MCSymbol * Symbol){
326 symbol_map::iterator i = SymbolMap.find(Symbol);
327 if (i != SymbolMap.end())
329 COFFSymbol *RetSymbol
330 = createCOFFEntity<COFFSymbol>(Symbol->getName(), Symbols);
331 SymbolMap[Symbol] = RetSymbol;
335 COFFSection *WinCOFFObjectWriter::createSection(StringRef Name) {
336 return createCOFFEntity<COFFSection>(Name, Sections);
339 /// A template used to lookup or create a symbol/section, and initialize it if
341 template <typename object_t, typename list_t>
342 object_t *WinCOFFObjectWriter::createCOFFEntity(StringRef Name,
344 object_t *Object = new object_t(Name);
346 List.push_back(Object);
351 /// This function takes a section data object from the assembler
352 /// and creates the associated COFF section staging object.
353 void WinCOFFObjectWriter::DefineSection(MCSectionData const &SectionData) {
354 assert(SectionData.getSection().getVariant() == MCSection::SV_COFF
355 && "Got non COFF section in the COFF backend!");
356 // FIXME: Not sure how to verify this (at least in a debug build).
357 MCSectionCOFF const &Sec =
358 static_cast<MCSectionCOFF const &>(SectionData.getSection());
360 COFFSection *coff_section = createSection(Sec.getSectionName());
361 COFFSymbol *coff_symbol = createSymbol(Sec.getSectionName());
363 coff_section->Symbol = coff_symbol;
364 coff_symbol->Section = coff_section;
365 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC;
367 // In this case the auxiliary symbol is a Section Definition.
368 coff_symbol->Aux.resize(1);
369 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
370 coff_symbol->Aux[0].AuxType = ATSectionDefinition;
371 coff_symbol->Aux[0].Aux.SectionDefinition.Selection = Sec.getSelection();
373 coff_section->Header.Characteristics = Sec.getCharacteristics();
375 uint32_t &Characteristics = coff_section->Header.Characteristics;
376 switch (SectionData.getAlignment()) {
377 case 1: Characteristics |= COFF::IMAGE_SCN_ALIGN_1BYTES; break;
378 case 2: Characteristics |= COFF::IMAGE_SCN_ALIGN_2BYTES; break;
379 case 4: Characteristics |= COFF::IMAGE_SCN_ALIGN_4BYTES; break;
380 case 8: Characteristics |= COFF::IMAGE_SCN_ALIGN_8BYTES; break;
381 case 16: Characteristics |= COFF::IMAGE_SCN_ALIGN_16BYTES; break;
382 case 32: Characteristics |= COFF::IMAGE_SCN_ALIGN_32BYTES; break;
383 case 64: Characteristics |= COFF::IMAGE_SCN_ALIGN_64BYTES; break;
384 case 128: Characteristics |= COFF::IMAGE_SCN_ALIGN_128BYTES; break;
385 case 256: Characteristics |= COFF::IMAGE_SCN_ALIGN_256BYTES; break;
386 case 512: Characteristics |= COFF::IMAGE_SCN_ALIGN_512BYTES; break;
387 case 1024: Characteristics |= COFF::IMAGE_SCN_ALIGN_1024BYTES; break;
388 case 2048: Characteristics |= COFF::IMAGE_SCN_ALIGN_2048BYTES; break;
389 case 4096: Characteristics |= COFF::IMAGE_SCN_ALIGN_4096BYTES; break;
390 case 8192: Characteristics |= COFF::IMAGE_SCN_ALIGN_8192BYTES; break;
392 llvm_unreachable("unsupported section alignment");
395 // Bind internal COFF section to MC section.
396 coff_section->MCData = &SectionData;
397 SectionMap[&SectionData.getSection()] = coff_section;
400 /// This function takes a section data object from the assembler
401 /// and creates the associated COFF symbol staging object.
402 void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
403 MCAssembler &Assembler) {
404 MCSymbol const &Symbol = SymbolData.getSymbol();
405 COFFSymbol *coff_symbol = GetOrCreateCOFFSymbol(&Symbol);
406 SymbolMap[&Symbol] = coff_symbol;
408 if (SymbolData.getFlags() & COFF::SF_WeakExternal) {
409 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
411 if (Symbol.isVariable()) {
412 const MCSymbolRefExpr *SymRef =
413 dyn_cast<MCSymbolRefExpr>(Symbol.getVariableValue());
416 report_fatal_error("Weak externals may only alias symbols");
418 coff_symbol->Other = GetOrCreateCOFFSymbol(&SymRef->getSymbol());
420 std::string WeakName = std::string(".weak.")
421 + Symbol.getName().str()
423 COFFSymbol *WeakDefault = createSymbol(WeakName);
424 WeakDefault->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
425 WeakDefault->Data.StorageClass = COFF::IMAGE_SYM_CLASS_EXTERNAL;
426 WeakDefault->Data.Type = 0;
427 WeakDefault->Data.Value = 0;
428 coff_symbol->Other = WeakDefault;
431 // Setup the Weak External auxiliary symbol.
432 coff_symbol->Aux.resize(1);
433 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
434 coff_symbol->Aux[0].AuxType = ATWeakExternal;
435 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = 0;
436 coff_symbol->Aux[0].Aux.WeakExternal.Characteristics =
437 COFF::IMAGE_WEAK_EXTERN_SEARCH_LIBRARY;
439 coff_symbol->MCData = &SymbolData;
441 const MCSymbolData &ResSymData =
442 Assembler.getSymbolData(Symbol.AliasedSymbol());
444 coff_symbol->Data.Type = (ResSymData.getFlags() & 0x0000FFFF) >> 0;
445 coff_symbol->Data.StorageClass = (ResSymData.getFlags() & 0x00FF0000) >> 16;
447 // If no storage class was specified in the streamer, define it here.
448 if (coff_symbol->Data.StorageClass == 0) {
449 bool external = ResSymData.isExternal() || (ResSymData.Fragment == NULL);
451 coff_symbol->Data.StorageClass =
452 external ? COFF::IMAGE_SYM_CLASS_EXTERNAL : COFF::IMAGE_SYM_CLASS_STATIC;
455 if (ResSymData.Fragment != NULL)
456 coff_symbol->Section =
457 SectionMap[&ResSymData.Fragment->getParent()->getSection()];
459 coff_symbol->MCData = &ResSymData;
463 /// making a section real involves assigned it a number and putting
464 /// name into the string table if needed
465 void WinCOFFObjectWriter::MakeSectionReal(COFFSection &S, size_t Number) {
466 if (S.Name.size() > COFF::NameSize) {
467 const unsigned Max6DecimalSize = 999999;
468 const unsigned Max7DecimalSize = 9999999;
469 uint64_t StringTableEntry = Strings.insert(S.Name.c_str());
471 if (StringTableEntry <= Max6DecimalSize) {
472 std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry));
473 } else if (StringTableEntry <= Max7DecimalSize) {
474 // With seven digits, we have to skip the terminating null. Because
475 // sprintf always appends it, we use a larger temporary buffer.
476 char buffer[9] = { };
477 std::sprintf(buffer, "/%d", unsigned(StringTableEntry));
478 std::memcpy(S.Header.Name, buffer, 8);
480 report_fatal_error("COFF string table is greater than 9,999,999 bytes.");
483 std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size());
486 S.Symbol->Data.SectionNumber = S.Number;
487 S.Symbol->Aux[0].Aux.SectionDefinition.Number = S.Number;
490 void WinCOFFObjectWriter::MakeSymbolReal(COFFSymbol &S, size_t Index) {
491 if (S.Name.size() > COFF::NameSize) {
492 size_t StringTableEntry = Strings.insert(S.Name.c_str());
494 S.set_name_offset(StringTableEntry);
496 std::memcpy(S.Data.Name, S.Name.c_str(), S.Name.size());
500 bool WinCOFFObjectWriter::ExportSection(COFFSection const *S) {
501 return !S->MCData->getFragmentList().empty();
504 bool WinCOFFObjectWriter::ExportSymbol(MCSymbolData const &SymbolData,
506 // This doesn't seem to be right. Strings referred to from the .data section
507 // need symbols so they can be linked to code in the .text section right?
509 // return Asm.isSymbolLinkerVisible (&SymbolData);
511 // For now, all non-variable symbols are exported,
512 // the linker will sort the rest out for us.
513 return SymbolData.isExternal() || !SymbolData.getSymbol().isVariable();
516 bool WinCOFFObjectWriter::IsPhysicalSection(COFFSection *S) {
517 return (S->Header.Characteristics
518 & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0;
521 //------------------------------------------------------------------------------
522 // entity writing methods
524 void WinCOFFObjectWriter::WriteFileHeader(const COFF::header &Header) {
525 WriteLE16(Header.Machine);
526 WriteLE16(Header.NumberOfSections);
527 WriteLE32(Header.TimeDateStamp);
528 WriteLE32(Header.PointerToSymbolTable);
529 WriteLE32(Header.NumberOfSymbols);
530 WriteLE16(Header.SizeOfOptionalHeader);
531 WriteLE16(Header.Characteristics);
534 void WinCOFFObjectWriter::WriteSymbol(const COFFSymbol *S) {
535 WriteBytes(StringRef(S->Data.Name, COFF::NameSize));
536 WriteLE32(S->Data.Value);
537 WriteLE16(S->Data.SectionNumber);
538 WriteLE16(S->Data.Type);
539 Write8(S->Data.StorageClass);
540 Write8(S->Data.NumberOfAuxSymbols);
541 WriteAuxiliarySymbols(S->Aux);
544 void WinCOFFObjectWriter::WriteAuxiliarySymbols(
545 const COFFSymbol::AuxiliarySymbols &S) {
546 for(COFFSymbol::AuxiliarySymbols::const_iterator i = S.begin(), e = S.end();
549 case ATFunctionDefinition:
550 WriteLE32(i->Aux.FunctionDefinition.TagIndex);
551 WriteLE32(i->Aux.FunctionDefinition.TotalSize);
552 WriteLE32(i->Aux.FunctionDefinition.PointerToLinenumber);
553 WriteLE32(i->Aux.FunctionDefinition.PointerToNextFunction);
554 WriteZeros(sizeof(i->Aux.FunctionDefinition.unused));
556 case ATbfAndefSymbol:
557 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused1));
558 WriteLE16(i->Aux.bfAndefSymbol.Linenumber);
559 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused2));
560 WriteLE32(i->Aux.bfAndefSymbol.PointerToNextFunction);
561 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused3));
564 WriteLE32(i->Aux.WeakExternal.TagIndex);
565 WriteLE32(i->Aux.WeakExternal.Characteristics);
566 WriteZeros(sizeof(i->Aux.WeakExternal.unused));
569 WriteBytes(StringRef(reinterpret_cast<const char *>(i->Aux.File.FileName),
570 sizeof(i->Aux.File.FileName)));
572 case ATSectionDefinition:
573 WriteLE32(i->Aux.SectionDefinition.Length);
574 WriteLE16(i->Aux.SectionDefinition.NumberOfRelocations);
575 WriteLE16(i->Aux.SectionDefinition.NumberOfLinenumbers);
576 WriteLE32(i->Aux.SectionDefinition.CheckSum);
577 WriteLE16(i->Aux.SectionDefinition.Number);
578 Write8(i->Aux.SectionDefinition.Selection);
579 WriteZeros(sizeof(i->Aux.SectionDefinition.unused));
585 void WinCOFFObjectWriter::WriteSectionHeader(const COFF::section &S) {
586 WriteBytes(StringRef(S.Name, COFF::NameSize));
588 WriteLE32(S.VirtualSize);
589 WriteLE32(S.VirtualAddress);
590 WriteLE32(S.SizeOfRawData);
591 WriteLE32(S.PointerToRawData);
592 WriteLE32(S.PointerToRelocations);
593 WriteLE32(S.PointerToLineNumbers);
594 WriteLE16(S.NumberOfRelocations);
595 WriteLE16(S.NumberOfLineNumbers);
596 WriteLE32(S.Characteristics);
599 void WinCOFFObjectWriter::WriteRelocation(const COFF::relocation &R) {
600 WriteLE32(R.VirtualAddress);
601 WriteLE32(R.SymbolTableIndex);
605 ////////////////////////////////////////////////////////////////////////////////
606 // MCObjectWriter interface implementations
608 void WinCOFFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
609 const MCAsmLayout &Layout) {
610 // "Define" each section & symbol. This creates section & symbol
611 // entries in the staging area.
613 for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e; i++)
616 for (MCAssembler::const_symbol_iterator i = Asm.symbol_begin(),
617 e = Asm.symbol_end(); i != e; i++) {
618 if (ExportSymbol(*i, Asm)) {
619 DefineSymbol(*i, Asm);
624 void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
625 const MCAsmLayout &Layout,
626 const MCFragment *Fragment,
627 const MCFixup &Fixup,
629 uint64_t &FixedValue) {
630 assert(Target.getSymA() != NULL && "Relocation must reference a symbol!");
632 const MCSymbol &Symbol = Target.getSymA()->getSymbol();
633 const MCSymbol &A = Symbol.AliasedSymbol();
634 MCSymbolData &A_SD = Asm.getSymbolData(A);
636 MCSectionData const *SectionData = Fragment->getParent();
638 // Mark this symbol as requiring an entry in the symbol table.
639 assert(SectionMap.find(&SectionData->getSection()) != SectionMap.end() &&
640 "Section must already have been defined in ExecutePostLayoutBinding!");
641 assert(SymbolMap.find(&A_SD.getSymbol()) != SymbolMap.end() &&
642 "Symbol must already have been defined in ExecutePostLayoutBinding!");
644 COFFSection *coff_section = SectionMap[&SectionData->getSection()];
645 COFFSymbol *coff_symbol = SymbolMap[&A_SD.getSymbol()];
646 const MCSymbolRefExpr *SymA = Target.getSymA();
647 const MCSymbolRefExpr *SymB = Target.getSymB();
648 const bool CrossSection = SymB &&
649 &SymA->getSymbol().getSection() != &SymB->getSymbol().getSection();
651 if (Target.getSymB()) {
652 const MCSymbol *B = &Target.getSymB()->getSymbol();
653 MCSymbolData &B_SD = Asm.getSymbolData(*B);
655 // Offset of the symbol in the section
656 int64_t a = Layout.getSymbolOffset(&B_SD);
658 // Ofeset of the relocation in the section
659 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
662 // In the case where we have SymbA and SymB, we just need to store the delta
663 // between the two symbols. Update FixedValue to account for the delta, and
664 // skip recording the relocation.
668 FixedValue = Target.getConstant();
671 COFFRelocation Reloc;
673 Reloc.Data.SymbolTableIndex = 0;
674 Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
676 // Turn relocations for temporary symbols into section relocations.
677 if (coff_symbol->MCData->getSymbol().isTemporary() || CrossSection) {
678 Reloc.Symb = coff_symbol->Section->Symbol;
679 FixedValue += Layout.getFragmentOffset(coff_symbol->MCData->Fragment)
680 + coff_symbol->MCData->getOffset();
682 Reloc.Symb = coff_symbol;
684 ++Reloc.Symb->Relocations;
686 Reloc.Data.VirtualAddress += Fixup.getOffset();
687 Reloc.Data.Type = TargetObjectWriter->getRelocType(Target, Fixup,
690 // FIXME: Can anyone explain what this does other than adjust for the size
692 if (Reloc.Data.Type == COFF::IMAGE_REL_AMD64_REL32 ||
693 Reloc.Data.Type == COFF::IMAGE_REL_I386_REL32)
696 coff_section->Relocations.push_back(Reloc);
699 void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
700 const MCAsmLayout &Layout) {
701 // Assign symbol and section indexes and offsets.
702 Header.NumberOfSections = 0;
704 DenseMap<COFFSection *, uint16_t> SectionIndices;
705 for (sections::iterator i = Sections.begin(),
706 e = Sections.end(); i != e; i++) {
707 if (Layout.getSectionAddressSize((*i)->MCData) > 0) {
708 size_t Number = ++Header.NumberOfSections;
709 SectionIndices[*i] = Number;
710 MakeSectionReal(**i, Number);
716 Header.NumberOfSymbols = 0;
718 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
719 COFFSymbol *coff_symbol = *i;
720 MCSymbolData const *SymbolData = coff_symbol->MCData;
722 // Update section number & offset for symbols that have them.
723 if ((SymbolData != NULL) && (SymbolData->Fragment != NULL)) {
724 assert(coff_symbol->Section != NULL);
726 coff_symbol->Data.SectionNumber = coff_symbol->Section->Number;
727 coff_symbol->Data.Value = Layout.getFragmentOffset(SymbolData->Fragment)
728 + SymbolData->Offset;
731 if (coff_symbol->should_keep()) {
732 MakeSymbolReal(*coff_symbol, Header.NumberOfSymbols++);
734 // Update auxiliary symbol info.
735 coff_symbol->Data.NumberOfAuxSymbols = coff_symbol->Aux.size();
736 Header.NumberOfSymbols += coff_symbol->Data.NumberOfAuxSymbols;
738 coff_symbol->Index = -1;
741 // Fixup weak external references.
742 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
743 COFFSymbol *coff_symbol = *i;
744 if (coff_symbol->Other != NULL) {
745 assert(coff_symbol->Index != -1);
746 assert(coff_symbol->Aux.size() == 1 &&
747 "Symbol must contain one aux symbol!");
748 assert(coff_symbol->Aux[0].AuxType == ATWeakExternal &&
749 "Symbol's aux symbol must be a Weak External!");
750 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = coff_symbol->Other->Index;
754 // Fixup associative COMDAT sections.
755 for (sections::iterator i = Sections.begin(),
756 e = Sections.end(); i != e; i++) {
757 if ((*i)->Symbol->Aux[0].Aux.SectionDefinition.Selection !=
758 COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE)
761 const MCSectionCOFF &MCSec = static_cast<const MCSectionCOFF &>(
762 (*i)->MCData->getSection());
764 COFFSection *Assoc = SectionMap.lookup(MCSec.getAssocSection());
766 report_fatal_error(Twine("Missing associated COMDAT section ") +
767 MCSec.getAssocSection()->getSectionName() +
768 " for section " + MCSec.getSectionName());
771 // Skip this section if the associated section is unused.
772 if (Assoc->Number == -1)
775 (*i)->Symbol->Aux[0].Aux.SectionDefinition.Number = SectionIndices[Assoc];
779 // Assign file offsets to COFF object file structures.
783 offset += COFF::HeaderSize;
784 offset += COFF::SectionSize * Header.NumberOfSections;
786 for (MCAssembler::const_iterator i = Asm.begin(),
789 COFFSection *Sec = SectionMap[&i->getSection()];
791 if (Sec->Number == -1)
794 Sec->Header.SizeOfRawData = Layout.getSectionAddressSize(i);
796 if (IsPhysicalSection(Sec)) {
797 Sec->Header.PointerToRawData = offset;
799 offset += Sec->Header.SizeOfRawData;
802 if (Sec->Relocations.size() > 0) {
803 bool RelocationsOverflow = Sec->Relocations.size() >= 0xffff;
805 if (RelocationsOverflow) {
806 // Signal overflow by setting NumberOfSections to max value. Actual
807 // size is found in reloc #0. Microsoft tools understand this.
808 Sec->Header.NumberOfRelocations = 0xffff;
810 Sec->Header.NumberOfRelocations = Sec->Relocations.size();
812 Sec->Header.PointerToRelocations = offset;
814 if (RelocationsOverflow) {
815 // Reloc #0 will contain actual count, so make room for it.
816 offset += COFF::RelocationSize;
819 offset += COFF::RelocationSize * Sec->Relocations.size();
821 for (relocations::iterator cr = Sec->Relocations.begin(),
822 er = Sec->Relocations.end();
824 assert((*cr).Symb->Index != -1);
825 (*cr).Data.SymbolTableIndex = (*cr).Symb->Index;
829 assert(Sec->Symbol->Aux.size() == 1
830 && "Section's symbol must have one aux!");
831 AuxSymbol &Aux = Sec->Symbol->Aux[0];
832 assert(Aux.AuxType == ATSectionDefinition &&
833 "Section's symbol's aux symbol must be a Section Definition!");
834 Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData;
835 Aux.Aux.SectionDefinition.NumberOfRelocations =
836 Sec->Header.NumberOfRelocations;
837 Aux.Aux.SectionDefinition.NumberOfLinenumbers =
838 Sec->Header.NumberOfLineNumbers;
841 Header.PointerToSymbolTable = offset;
843 Header.TimeDateStamp = sys::TimeValue::now().toEpochTime();
845 // Write it all to disk...
846 WriteFileHeader(Header);
849 sections::iterator i, ie;
850 MCAssembler::const_iterator j, je;
852 for (i = Sections.begin(), ie = Sections.end(); i != ie; i++)
853 if ((*i)->Number != -1) {
854 if ((*i)->Relocations.size() >= 0xffff) {
855 (*i)->Header.Characteristics |= COFF::IMAGE_SCN_LNK_NRELOC_OVFL;
857 WriteSectionHeader((*i)->Header);
860 for (i = Sections.begin(), ie = Sections.end(),
861 j = Asm.begin(), je = Asm.end();
862 (i != ie) && (j != je); ++i, ++j) {
864 if ((*i)->Number == -1)
867 if ((*i)->Header.PointerToRawData != 0) {
868 assert(OS.tell() == (*i)->Header.PointerToRawData &&
869 "Section::PointerToRawData is insane!");
871 Asm.writeSectionData(j, Layout);
874 if ((*i)->Relocations.size() > 0) {
875 assert(OS.tell() == (*i)->Header.PointerToRelocations &&
876 "Section::PointerToRelocations is insane!");
878 if ((*i)->Relocations.size() >= 0xffff) {
879 // In case of overflow, write actual relocation count as first
880 // relocation. Including the synthetic reloc itself (+ 1).
882 r.VirtualAddress = (*i)->Relocations.size() + 1;
883 r.SymbolTableIndex = 0;
888 for (relocations::const_iterator k = (*i)->Relocations.begin(),
889 ke = (*i)->Relocations.end();
891 WriteRelocation(k->Data);
894 assert((*i)->Header.PointerToRelocations == 0 &&
895 "Section::PointerToRelocations is insane!");
899 assert(OS.tell() == Header.PointerToSymbolTable &&
900 "Header::PointerToSymbolTable is insane!");
902 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++)
903 if ((*i)->Index != -1)
906 OS.write((char const *)&Strings.Data.front(), Strings.Data.size());
909 MCWinCOFFObjectTargetWriter::MCWinCOFFObjectTargetWriter(unsigned Machine_) :
913 //------------------------------------------------------------------------------
914 // WinCOFFObjectWriter factory function
917 MCObjectWriter *createWinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
919 return new WinCOFFObjectWriter(MOTW, OS);