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, MCAssembler &Assembler,
152 const MCAsmLayout &Layout);
154 void MakeSymbolReal(COFFSymbol &S, size_t Index);
155 void MakeSectionReal(COFFSection &S, size_t Number);
157 bool IsPhysicalSection(COFFSection *S);
159 // Entity writing methods.
161 void WriteFileHeader(const COFF::header &Header);
162 void WriteSymbol(const COFFSymbol *S);
163 void WriteAuxiliarySymbols(const COFFSymbol::AuxiliarySymbols &S);
164 void WriteSectionHeader(const COFF::section &S);
165 void WriteRelocation(const COFF::relocation &R);
167 // MCObjectWriter interface implementation.
169 void ExecutePostLayoutBinding(MCAssembler &Asm, const MCAsmLayout &Layout);
171 void RecordRelocation(const MCAssembler &Asm,
172 const MCAsmLayout &Layout,
173 const MCFragment *Fragment,
174 const MCFixup &Fixup,
176 uint64_t &FixedValue);
178 void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
182 static inline void write_uint32_le(void *Data, uint32_t const &Value) {
183 uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
184 Ptr[0] = (Value & 0x000000FF) >> 0;
185 Ptr[1] = (Value & 0x0000FF00) >> 8;
186 Ptr[2] = (Value & 0x00FF0000) >> 16;
187 Ptr[3] = (Value & 0xFF000000) >> 24;
190 //------------------------------------------------------------------------------
191 // Symbol class implementation
193 COFFSymbol::COFFSymbol(StringRef name)
194 : Name(name.begin(), name.end())
199 memset(&Data, 0, sizeof(Data));
202 size_t COFFSymbol::size() const {
203 return COFF::SymbolSize + (Data.NumberOfAuxSymbols * COFF::SymbolSize);
206 // In the case that the name does not fit within 8 bytes, the offset
207 // into the string table is stored in the last 4 bytes instead, leaving
208 // the first 4 bytes as 0.
209 void COFFSymbol::set_name_offset(uint32_t Offset) {
210 write_uint32_le(Data.Name + 0, 0);
211 write_uint32_le(Data.Name + 4, Offset);
214 /// logic to decide if the symbol should be reported in the symbol table
215 bool COFFSymbol::should_keep() const {
216 // no section means its external, keep it
220 // if it has relocations pointing at it, keep it
221 if (Relocations > 0) {
222 assert(Section->Number != -1 && "Sections with relocations must be real!");
226 // if the section its in is being droped, drop it
227 if (Section->Number == -1)
230 // if it is the section symbol, keep it
231 if (Section->Symbol == this)
234 // if its temporary, drop it
235 if (MCData && MCData->getSymbol().isTemporary())
238 // otherwise, keep it
242 //------------------------------------------------------------------------------
243 // Section class implementation
245 COFFSection::COFFSection(StringRef name)
249 memset(&Header, 0, sizeof(Header));
252 size_t COFFSection::size() {
253 return COFF::SectionSize;
256 //------------------------------------------------------------------------------
257 // StringTable class implementation
259 /// Write the length of the string table into Data.
260 /// The length of the string table includes uint32 length header.
261 void StringTable::update_length() {
262 write_uint32_le(&Data.front(), Data.size());
265 StringTable::StringTable() {
266 // The string table data begins with the length of the entire string table
267 // including the length header. Allocate space for this header.
272 size_t StringTable::size() const {
276 /// Add String to the table iff it is not already there.
277 /// @returns the index into the string table where the string is now located.
278 size_t StringTable::insert(StringRef String) {
279 map::iterator i = Map.find(String);
284 size_t Offset = Data.size();
286 // Insert string data into string table.
287 Data.insert(Data.end(), String.begin(), String.end());
288 Data.push_back('\0');
290 // Put a reference to it in the map.
291 Map[String] = Offset;
293 // Update the internal length field.
299 //------------------------------------------------------------------------------
300 // WinCOFFObjectWriter class implementation
302 WinCOFFObjectWriter::WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
304 : MCObjectWriter(OS, true)
305 , TargetObjectWriter(MOTW) {
306 memset(&Header, 0, sizeof(Header));
308 Header.Machine = TargetObjectWriter->getMachine();
311 WinCOFFObjectWriter::~WinCOFFObjectWriter() {
312 for (symbols::iterator I = Symbols.begin(), E = Symbols.end(); I != E; ++I)
314 for (sections::iterator I = Sections.begin(), E = Sections.end(); I != E; ++I)
318 COFFSymbol *WinCOFFObjectWriter::createSymbol(StringRef Name) {
319 return createCOFFEntity<COFFSymbol>(Name, Symbols);
322 COFFSymbol *WinCOFFObjectWriter::GetOrCreateCOFFSymbol(const MCSymbol * Symbol){
323 symbol_map::iterator i = SymbolMap.find(Symbol);
324 if (i != SymbolMap.end())
326 COFFSymbol *RetSymbol
327 = createCOFFEntity<COFFSymbol>(Symbol->getName(), Symbols);
328 SymbolMap[Symbol] = RetSymbol;
332 COFFSection *WinCOFFObjectWriter::createSection(StringRef Name) {
333 return createCOFFEntity<COFFSection>(Name, Sections);
336 /// A template used to lookup or create a symbol/section, and initialize it if
338 template <typename object_t, typename list_t>
339 object_t *WinCOFFObjectWriter::createCOFFEntity(StringRef Name,
341 object_t *Object = new object_t(Name);
343 List.push_back(Object);
348 /// This function takes a section data object from the assembler
349 /// and creates the associated COFF section staging object.
350 void WinCOFFObjectWriter::DefineSection(MCSectionData const &SectionData) {
351 assert(SectionData.getSection().getVariant() == MCSection::SV_COFF
352 && "Got non COFF section in the COFF backend!");
353 // FIXME: Not sure how to verify this (at least in a debug build).
354 MCSectionCOFF const &Sec =
355 static_cast<MCSectionCOFF const &>(SectionData.getSection());
357 COFFSection *coff_section = createSection(Sec.getSectionName());
358 COFFSymbol *coff_symbol = createSymbol(Sec.getSectionName());
360 coff_section->Symbol = coff_symbol;
361 coff_symbol->Section = coff_section;
362 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC;
364 // In this case the auxiliary symbol is a Section Definition.
365 coff_symbol->Aux.resize(1);
366 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
367 coff_symbol->Aux[0].AuxType = ATSectionDefinition;
368 coff_symbol->Aux[0].Aux.SectionDefinition.Selection = Sec.getSelection();
370 coff_section->Header.Characteristics = Sec.getCharacteristics();
372 uint32_t &Characteristics = coff_section->Header.Characteristics;
373 switch (SectionData.getAlignment()) {
374 case 1: Characteristics |= COFF::IMAGE_SCN_ALIGN_1BYTES; break;
375 case 2: Characteristics |= COFF::IMAGE_SCN_ALIGN_2BYTES; break;
376 case 4: Characteristics |= COFF::IMAGE_SCN_ALIGN_4BYTES; break;
377 case 8: Characteristics |= COFF::IMAGE_SCN_ALIGN_8BYTES; break;
378 case 16: Characteristics |= COFF::IMAGE_SCN_ALIGN_16BYTES; break;
379 case 32: Characteristics |= COFF::IMAGE_SCN_ALIGN_32BYTES; break;
380 case 64: Characteristics |= COFF::IMAGE_SCN_ALIGN_64BYTES; break;
381 case 128: Characteristics |= COFF::IMAGE_SCN_ALIGN_128BYTES; break;
382 case 256: Characteristics |= COFF::IMAGE_SCN_ALIGN_256BYTES; break;
383 case 512: Characteristics |= COFF::IMAGE_SCN_ALIGN_512BYTES; break;
384 case 1024: Characteristics |= COFF::IMAGE_SCN_ALIGN_1024BYTES; break;
385 case 2048: Characteristics |= COFF::IMAGE_SCN_ALIGN_2048BYTES; break;
386 case 4096: Characteristics |= COFF::IMAGE_SCN_ALIGN_4096BYTES; break;
387 case 8192: Characteristics |= COFF::IMAGE_SCN_ALIGN_8192BYTES; break;
389 llvm_unreachable("unsupported section alignment");
392 // Bind internal COFF section to MC section.
393 coff_section->MCData = &SectionData;
394 SectionMap[&SectionData.getSection()] = coff_section;
397 /// This function takes a section data object from the assembler
398 /// and creates the associated COFF symbol staging object.
399 void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
400 MCAssembler &Assembler,
401 const MCAsmLayout &Layout) {
402 MCSymbol const &Symbol = SymbolData.getSymbol();
403 COFFSymbol *coff_symbol = GetOrCreateCOFFSymbol(&Symbol);
404 SymbolMap[&Symbol] = coff_symbol;
406 if (SymbolData.getFlags() & COFF::SF_WeakExternal) {
407 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
409 if (Symbol.isVariable()) {
410 const MCSymbolRefExpr *SymRef =
411 dyn_cast<MCSymbolRefExpr>(Symbol.getVariableValue());
414 report_fatal_error("Weak externals may only alias symbols");
416 coff_symbol->Other = GetOrCreateCOFFSymbol(&SymRef->getSymbol());
418 std::string WeakName = std::string(".weak.")
419 + Symbol.getName().str()
421 COFFSymbol *WeakDefault = createSymbol(WeakName);
422 WeakDefault->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
423 WeakDefault->Data.StorageClass = COFF::IMAGE_SYM_CLASS_EXTERNAL;
424 WeakDefault->Data.Type = 0;
425 WeakDefault->Data.Value = 0;
426 coff_symbol->Other = WeakDefault;
429 // Setup the Weak External auxiliary symbol.
430 coff_symbol->Aux.resize(1);
431 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
432 coff_symbol->Aux[0].AuxType = ATWeakExternal;
433 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = 0;
434 coff_symbol->Aux[0].Aux.WeakExternal.Characteristics =
435 COFF::IMAGE_WEAK_EXTERN_SEARCH_LIBRARY;
437 coff_symbol->MCData = &SymbolData;
439 const MCSymbolData &ResSymData =
440 Assembler.getSymbolData(Symbol.AliasedSymbol());
442 if (Symbol.isVariable()) {
444 if (Symbol.getVariableValue()->EvaluateAsAbsolute(Addr, Layout))
445 coff_symbol->Data.Value = Addr;
448 coff_symbol->Data.Type = (ResSymData.getFlags() & 0x0000FFFF) >> 0;
449 coff_symbol->Data.StorageClass = (ResSymData.getFlags() & 0x00FF0000) >> 16;
451 // If no storage class was specified in the streamer, define it here.
452 if (coff_symbol->Data.StorageClass == 0) {
453 bool external = ResSymData.isExternal() || (ResSymData.Fragment == NULL);
455 coff_symbol->Data.StorageClass =
456 external ? COFF::IMAGE_SYM_CLASS_EXTERNAL : COFF::IMAGE_SYM_CLASS_STATIC;
459 if (Symbol.isAbsolute() || Symbol.AliasedSymbol().isVariable())
460 coff_symbol->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
461 else if (ResSymData.Fragment != NULL)
462 coff_symbol->Section =
463 SectionMap[&ResSymData.Fragment->getParent()->getSection()];
465 coff_symbol->MCData = &ResSymData;
469 /// making a section real involves assigned it a number and putting
470 /// name into the string table if needed
471 void WinCOFFObjectWriter::MakeSectionReal(COFFSection &S, size_t Number) {
472 if (S.Name.size() > COFF::NameSize) {
473 const unsigned Max6DecimalSize = 999999;
474 const unsigned Max7DecimalSize = 9999999;
475 uint64_t StringTableEntry = Strings.insert(S.Name.c_str());
477 if (StringTableEntry <= Max6DecimalSize) {
478 std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry));
479 } else if (StringTableEntry <= Max7DecimalSize) {
480 // With seven digits, we have to skip the terminating null. Because
481 // sprintf always appends it, we use a larger temporary buffer.
482 char buffer[9] = { };
483 std::sprintf(buffer, "/%d", unsigned(StringTableEntry));
484 std::memcpy(S.Header.Name, buffer, 8);
486 report_fatal_error("COFF string table is greater than 9,999,999 bytes.");
489 std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size());
492 S.Symbol->Data.SectionNumber = S.Number;
493 S.Symbol->Aux[0].Aux.SectionDefinition.Number = S.Number;
496 void WinCOFFObjectWriter::MakeSymbolReal(COFFSymbol &S, size_t Index) {
497 if (S.Name.size() > COFF::NameSize) {
498 size_t StringTableEntry = Strings.insert(S.Name.c_str());
500 S.set_name_offset(StringTableEntry);
502 std::memcpy(S.Data.Name, S.Name.c_str(), S.Name.size());
506 bool WinCOFFObjectWriter::IsPhysicalSection(COFFSection *S) {
507 return (S->Header.Characteristics
508 & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0;
511 //------------------------------------------------------------------------------
512 // entity writing methods
514 void WinCOFFObjectWriter::WriteFileHeader(const COFF::header &Header) {
515 WriteLE16(Header.Machine);
516 WriteLE16(Header.NumberOfSections);
517 WriteLE32(Header.TimeDateStamp);
518 WriteLE32(Header.PointerToSymbolTable);
519 WriteLE32(Header.NumberOfSymbols);
520 WriteLE16(Header.SizeOfOptionalHeader);
521 WriteLE16(Header.Characteristics);
524 void WinCOFFObjectWriter::WriteSymbol(const COFFSymbol *S) {
525 WriteBytes(StringRef(S->Data.Name, COFF::NameSize));
526 WriteLE32(S->Data.Value);
527 WriteLE16(S->Data.SectionNumber);
528 WriteLE16(S->Data.Type);
529 Write8(S->Data.StorageClass);
530 Write8(S->Data.NumberOfAuxSymbols);
531 WriteAuxiliarySymbols(S->Aux);
534 void WinCOFFObjectWriter::WriteAuxiliarySymbols(
535 const COFFSymbol::AuxiliarySymbols &S) {
536 for(COFFSymbol::AuxiliarySymbols::const_iterator i = S.begin(), e = S.end();
539 case ATFunctionDefinition:
540 WriteLE32(i->Aux.FunctionDefinition.TagIndex);
541 WriteLE32(i->Aux.FunctionDefinition.TotalSize);
542 WriteLE32(i->Aux.FunctionDefinition.PointerToLinenumber);
543 WriteLE32(i->Aux.FunctionDefinition.PointerToNextFunction);
544 WriteZeros(sizeof(i->Aux.FunctionDefinition.unused));
546 case ATbfAndefSymbol:
547 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused1));
548 WriteLE16(i->Aux.bfAndefSymbol.Linenumber);
549 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused2));
550 WriteLE32(i->Aux.bfAndefSymbol.PointerToNextFunction);
551 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused3));
554 WriteLE32(i->Aux.WeakExternal.TagIndex);
555 WriteLE32(i->Aux.WeakExternal.Characteristics);
556 WriteZeros(sizeof(i->Aux.WeakExternal.unused));
559 WriteBytes(StringRef(reinterpret_cast<const char *>(i->Aux.File.FileName),
560 sizeof(i->Aux.File.FileName)));
562 case ATSectionDefinition:
563 WriteLE32(i->Aux.SectionDefinition.Length);
564 WriteLE16(i->Aux.SectionDefinition.NumberOfRelocations);
565 WriteLE16(i->Aux.SectionDefinition.NumberOfLinenumbers);
566 WriteLE32(i->Aux.SectionDefinition.CheckSum);
567 WriteLE16(i->Aux.SectionDefinition.Number);
568 Write8(i->Aux.SectionDefinition.Selection);
569 WriteZeros(sizeof(i->Aux.SectionDefinition.unused));
575 void WinCOFFObjectWriter::WriteSectionHeader(const COFF::section &S) {
576 WriteBytes(StringRef(S.Name, COFF::NameSize));
578 WriteLE32(S.VirtualSize);
579 WriteLE32(S.VirtualAddress);
580 WriteLE32(S.SizeOfRawData);
581 WriteLE32(S.PointerToRawData);
582 WriteLE32(S.PointerToRelocations);
583 WriteLE32(S.PointerToLineNumbers);
584 WriteLE16(S.NumberOfRelocations);
585 WriteLE16(S.NumberOfLineNumbers);
586 WriteLE32(S.Characteristics);
589 void WinCOFFObjectWriter::WriteRelocation(const COFF::relocation &R) {
590 WriteLE32(R.VirtualAddress);
591 WriteLE32(R.SymbolTableIndex);
595 ////////////////////////////////////////////////////////////////////////////////
596 // MCObjectWriter interface implementations
598 void WinCOFFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
599 const MCAsmLayout &Layout) {
600 // "Define" each section & symbol. This creates section & symbol
601 // entries in the staging area.
603 for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e; i++)
606 for (MCAssembler::const_symbol_iterator i = Asm.symbol_begin(),
607 e = Asm.symbol_end();
609 DefineSymbol(*i, Asm, Layout);
612 void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
613 const MCAsmLayout &Layout,
614 const MCFragment *Fragment,
615 const MCFixup &Fixup,
617 uint64_t &FixedValue) {
618 assert(Target.getSymA() != NULL && "Relocation must reference a symbol!");
620 const MCSymbol &Symbol = Target.getSymA()->getSymbol();
621 const MCSymbol &A = Symbol.AliasedSymbol();
622 MCSymbolData &A_SD = Asm.getSymbolData(A);
624 MCSectionData const *SectionData = Fragment->getParent();
626 // Mark this symbol as requiring an entry in the symbol table.
627 assert(SectionMap.find(&SectionData->getSection()) != SectionMap.end() &&
628 "Section must already have been defined in ExecutePostLayoutBinding!");
629 assert(SymbolMap.find(&A_SD.getSymbol()) != SymbolMap.end() &&
630 "Symbol must already have been defined in ExecutePostLayoutBinding!");
632 COFFSection *coff_section = SectionMap[&SectionData->getSection()];
633 COFFSymbol *coff_symbol = SymbolMap[&A_SD.getSymbol()];
634 const MCSymbolRefExpr *SymA = Target.getSymA();
635 const MCSymbolRefExpr *SymB = Target.getSymB();
636 const bool CrossSection = SymB &&
637 &SymA->getSymbol().getSection() != &SymB->getSymbol().getSection();
639 if (Target.getSymB()) {
640 const MCSymbol *B = &Target.getSymB()->getSymbol();
641 MCSymbolData &B_SD = Asm.getSymbolData(*B);
643 // Offset of the symbol in the section
644 int64_t a = Layout.getSymbolOffset(&B_SD);
646 // Ofeset of the relocation in the section
647 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
650 // In the case where we have SymbA and SymB, we just need to store the delta
651 // between the two symbols. Update FixedValue to account for the delta, and
652 // skip recording the relocation.
656 FixedValue = Target.getConstant();
659 COFFRelocation Reloc;
661 Reloc.Data.SymbolTableIndex = 0;
662 Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
664 // Turn relocations for temporary symbols into section relocations.
665 if (coff_symbol->MCData->getSymbol().isTemporary() || CrossSection) {
666 Reloc.Symb = coff_symbol->Section->Symbol;
667 FixedValue += Layout.getFragmentOffset(coff_symbol->MCData->Fragment)
668 + coff_symbol->MCData->getOffset();
670 Reloc.Symb = coff_symbol;
672 ++Reloc.Symb->Relocations;
674 Reloc.Data.VirtualAddress += Fixup.getOffset();
675 Reloc.Data.Type = TargetObjectWriter->getRelocType(Target, Fixup,
678 // FIXME: Can anyone explain what this does other than adjust for the size
680 if (Reloc.Data.Type == COFF::IMAGE_REL_AMD64_REL32 ||
681 Reloc.Data.Type == COFF::IMAGE_REL_I386_REL32)
684 coff_section->Relocations.push_back(Reloc);
687 void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
688 const MCAsmLayout &Layout) {
689 // Assign symbol and section indexes and offsets.
690 Header.NumberOfSections = 0;
692 DenseMap<COFFSection *, uint16_t> SectionIndices;
693 for (sections::iterator i = Sections.begin(),
694 e = Sections.end(); i != e; i++) {
695 if (Layout.getSectionAddressSize((*i)->MCData) > 0) {
696 size_t Number = ++Header.NumberOfSections;
697 SectionIndices[*i] = Number;
698 MakeSectionReal(**i, Number);
704 Header.NumberOfSymbols = 0;
706 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
707 COFFSymbol *coff_symbol = *i;
708 MCSymbolData const *SymbolData = coff_symbol->MCData;
710 // Update section number & offset for symbols that have them.
711 if ((SymbolData != NULL) && (SymbolData->Fragment != NULL)) {
712 assert(coff_symbol->Section != NULL);
714 coff_symbol->Data.SectionNumber = coff_symbol->Section->Number;
715 coff_symbol->Data.Value = Layout.getFragmentOffset(SymbolData->Fragment)
716 + SymbolData->Offset;
719 if (coff_symbol->should_keep()) {
720 MakeSymbolReal(*coff_symbol, Header.NumberOfSymbols++);
722 // Update auxiliary symbol info.
723 coff_symbol->Data.NumberOfAuxSymbols = coff_symbol->Aux.size();
724 Header.NumberOfSymbols += coff_symbol->Data.NumberOfAuxSymbols;
726 coff_symbol->Index = -1;
729 // Fixup weak external references.
730 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
731 COFFSymbol *coff_symbol = *i;
732 if (coff_symbol->Other != NULL) {
733 assert(coff_symbol->Index != -1);
734 assert(coff_symbol->Aux.size() == 1 &&
735 "Symbol must contain one aux symbol!");
736 assert(coff_symbol->Aux[0].AuxType == ATWeakExternal &&
737 "Symbol's aux symbol must be a Weak External!");
738 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = coff_symbol->Other->Index;
742 // Fixup associative COMDAT sections.
743 for (sections::iterator i = Sections.begin(),
744 e = Sections.end(); i != e; i++) {
745 if ((*i)->Symbol->Aux[0].Aux.SectionDefinition.Selection !=
746 COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE)
749 const MCSectionCOFF &MCSec = static_cast<const MCSectionCOFF &>(
750 (*i)->MCData->getSection());
752 COFFSection *Assoc = SectionMap.lookup(MCSec.getAssocSection());
754 report_fatal_error(Twine("Missing associated COMDAT section ") +
755 MCSec.getAssocSection()->getSectionName() +
756 " for section " + MCSec.getSectionName());
759 // Skip this section if the associated section is unused.
760 if (Assoc->Number == -1)
763 (*i)->Symbol->Aux[0].Aux.SectionDefinition.Number = SectionIndices[Assoc];
767 // Assign file offsets to COFF object file structures.
771 offset += COFF::HeaderSize;
772 offset += COFF::SectionSize * Header.NumberOfSections;
774 for (MCAssembler::const_iterator i = Asm.begin(),
777 COFFSection *Sec = SectionMap[&i->getSection()];
779 if (Sec->Number == -1)
782 Sec->Header.SizeOfRawData = Layout.getSectionAddressSize(i);
784 if (IsPhysicalSection(Sec)) {
785 Sec->Header.PointerToRawData = offset;
787 offset += Sec->Header.SizeOfRawData;
790 if (Sec->Relocations.size() > 0) {
791 bool RelocationsOverflow = Sec->Relocations.size() >= 0xffff;
793 if (RelocationsOverflow) {
794 // Signal overflow by setting NumberOfSections to max value. Actual
795 // size is found in reloc #0. Microsoft tools understand this.
796 Sec->Header.NumberOfRelocations = 0xffff;
798 Sec->Header.NumberOfRelocations = Sec->Relocations.size();
800 Sec->Header.PointerToRelocations = offset;
802 if (RelocationsOverflow) {
803 // Reloc #0 will contain actual count, so make room for it.
804 offset += COFF::RelocationSize;
807 offset += COFF::RelocationSize * Sec->Relocations.size();
809 for (relocations::iterator cr = Sec->Relocations.begin(),
810 er = Sec->Relocations.end();
812 assert((*cr).Symb->Index != -1);
813 (*cr).Data.SymbolTableIndex = (*cr).Symb->Index;
817 assert(Sec->Symbol->Aux.size() == 1
818 && "Section's symbol must have one aux!");
819 AuxSymbol &Aux = Sec->Symbol->Aux[0];
820 assert(Aux.AuxType == ATSectionDefinition &&
821 "Section's symbol's aux symbol must be a Section Definition!");
822 Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData;
823 Aux.Aux.SectionDefinition.NumberOfRelocations =
824 Sec->Header.NumberOfRelocations;
825 Aux.Aux.SectionDefinition.NumberOfLinenumbers =
826 Sec->Header.NumberOfLineNumbers;
829 Header.PointerToSymbolTable = offset;
831 Header.TimeDateStamp = sys::TimeValue::now().toEpochTime();
833 // Write it all to disk...
834 WriteFileHeader(Header);
837 sections::iterator i, ie;
838 MCAssembler::const_iterator j, je;
840 for (i = Sections.begin(), ie = Sections.end(); i != ie; i++)
841 if ((*i)->Number != -1) {
842 if ((*i)->Relocations.size() >= 0xffff) {
843 (*i)->Header.Characteristics |= COFF::IMAGE_SCN_LNK_NRELOC_OVFL;
845 WriteSectionHeader((*i)->Header);
848 for (i = Sections.begin(), ie = Sections.end(),
849 j = Asm.begin(), je = Asm.end();
850 (i != ie) && (j != je); ++i, ++j) {
852 if ((*i)->Number == -1)
855 if ((*i)->Header.PointerToRawData != 0) {
856 assert(OS.tell() == (*i)->Header.PointerToRawData &&
857 "Section::PointerToRawData is insane!");
859 Asm.writeSectionData(j, Layout);
862 if ((*i)->Relocations.size() > 0) {
863 assert(OS.tell() == (*i)->Header.PointerToRelocations &&
864 "Section::PointerToRelocations is insane!");
866 if ((*i)->Relocations.size() >= 0xffff) {
867 // In case of overflow, write actual relocation count as first
868 // relocation. Including the synthetic reloc itself (+ 1).
870 r.VirtualAddress = (*i)->Relocations.size() + 1;
871 r.SymbolTableIndex = 0;
876 for (relocations::const_iterator k = (*i)->Relocations.begin(),
877 ke = (*i)->Relocations.end();
879 WriteRelocation(k->Data);
882 assert((*i)->Header.PointerToRelocations == 0 &&
883 "Section::PointerToRelocations is insane!");
887 assert(OS.tell() == Header.PointerToSymbolTable &&
888 "Header::PointerToSymbolTable is insane!");
890 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++)
891 if ((*i)->Index != -1)
894 OS.write((char const *)&Strings.Data.front(), Strings.Data.size());
897 MCWinCOFFObjectTargetWriter::MCWinCOFFObjectTargetWriter(unsigned Machine_) :
901 //------------------------------------------------------------------------------
902 // WinCOFFObjectWriter factory function
905 MCObjectWriter *createWinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
907 return new WinCOFFObjectWriter(MOTW, OS);