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/MC/MCAsmLayout.h"
22 #include "llvm/MC/MCAssembler.h"
23 #include "llvm/MC/MCContext.h"
24 #include "llvm/MC/MCExpr.h"
25 #include "llvm/MC/MCObjectWriter.h"
26 #include "llvm/MC/MCSection.h"
27 #include "llvm/MC/MCSectionCOFF.h"
28 #include "llvm/MC/MCSymbol.h"
29 #include "llvm/MC/MCValue.h"
30 #include "llvm/Support/COFF.h"
31 #include "llvm/Support/Debug.h"
32 #include "llvm/Support/ErrorHandling.h"
33 #include "llvm/Support/TimeValue.h"
39 typedef SmallString<COFF::NameSize> name;
50 AuxiliaryType AuxType;
61 typedef SmallVector<AuxSymbol, 1> AuxiliarySymbols;
70 MCSymbolData const *MCData;
72 COFFSymbol(StringRef name);
74 void set_name_offset(uint32_t Offset);
76 bool should_keep() const;
79 // This class contains staging data for a COFF relocation entry.
80 struct COFFRelocation {
81 COFF::relocation Data;
84 COFFRelocation() : Symb(NULL) {}
85 static size_t size() { return COFF::RelocationSize; }
88 typedef std::vector<COFFRelocation> relocations;
96 MCSectionData const *MCData;
98 relocations Relocations;
100 COFFSection(StringRef name);
101 static size_t size();
104 // This class holds the COFF string table.
106 typedef StringMap<size_t> map;
109 void update_length();
111 std::vector<char> Data;
115 size_t insert(StringRef String);
118 class WinCOFFObjectWriter : public MCObjectWriter {
121 typedef std::vector<COFFSymbol*> symbols;
122 typedef std::vector<COFFSection*> sections;
124 typedef DenseMap<MCSymbol const *, COFFSymbol *> symbol_map;
125 typedef DenseMap<MCSection const *, COFFSection *> section_map;
127 llvm::OwningPtr<MCWinCOFFObjectTargetWriter> TargetObjectWriter;
129 // Root level file contents.
135 // Maps used during object file creation.
136 section_map SectionMap;
137 symbol_map SymbolMap;
139 WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW, raw_ostream &OS);
140 ~WinCOFFObjectWriter();
142 COFFSymbol *createSymbol(StringRef Name);
143 COFFSymbol *GetOrCreateCOFFSymbol(const MCSymbol * Symbol);
144 COFFSection *createSection(StringRef Name);
146 template <typename object_t, typename list_t>
147 object_t *createCOFFEntity(StringRef Name, list_t &List);
149 void DefineSection(MCSectionData const &SectionData);
150 void DefineSymbol(MCSymbolData const &SymbolData, MCAssembler &Assembler);
152 void MakeSymbolReal(COFFSymbol &S, size_t Index);
153 void MakeSectionReal(COFFSection &S, size_t Number);
155 bool ExportSection(COFFSection const *S);
156 bool ExportSymbol(MCSymbolData const &SymbolData, MCAssembler &Asm);
158 bool IsPhysicalSection(COFFSection *S);
160 // Entity writing methods.
162 void WriteFileHeader(const COFF::header &Header);
163 void WriteSymbol(const COFFSymbol *S);
164 void WriteAuxiliarySymbols(const COFFSymbol::AuxiliarySymbols &S);
165 void WriteSectionHeader(const COFF::section &S);
166 void WriteRelocation(const COFF::relocation &R);
168 // MCObjectWriter interface implementation.
170 void ExecutePostLayoutBinding(MCAssembler &Asm, const MCAsmLayout &Layout);
172 void RecordRelocation(const MCAssembler &Asm,
173 const MCAsmLayout &Layout,
174 const MCFragment *Fragment,
175 const MCFixup &Fixup,
177 uint64_t &FixedValue);
179 void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
183 static inline void write_uint32_le(void *Data, uint32_t const &Value) {
184 uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
185 Ptr[0] = (Value & 0x000000FF) >> 0;
186 Ptr[1] = (Value & 0x0000FF00) >> 8;
187 Ptr[2] = (Value & 0x00FF0000) >> 16;
188 Ptr[3] = (Value & 0xFF000000) >> 24;
191 static inline void write_uint16_le(void *Data, uint16_t const &Value) {
192 uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
193 Ptr[0] = (Value & 0x00FF) >> 0;
194 Ptr[1] = (Value & 0xFF00) >> 8;
197 static inline void write_uint8_le(void *Data, uint8_t const &Value) {
198 uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
199 Ptr[0] = (Value & 0xFF) >> 0;
202 //------------------------------------------------------------------------------
203 // Symbol class implementation
205 COFFSymbol::COFFSymbol(StringRef name)
206 : Name(name.begin(), name.end())
211 memset(&Data, 0, sizeof(Data));
214 size_t COFFSymbol::size() const {
215 return COFF::SymbolSize + (Data.NumberOfAuxSymbols * COFF::SymbolSize);
218 // In the case that the name does not fit within 8 bytes, the offset
219 // into the string table is stored in the last 4 bytes instead, leaving
220 // the first 4 bytes as 0.
221 void COFFSymbol::set_name_offset(uint32_t Offset) {
222 write_uint32_le(Data.Name + 0, 0);
223 write_uint32_le(Data.Name + 4, Offset);
226 /// logic to decide if the symbol should be reported in the symbol table
227 bool COFFSymbol::should_keep() const {
228 // no section means its external, keep it
232 // if it has relocations pointing at it, keep it
233 if (Relocations > 0) {
234 assert(Section->Number != -1 && "Sections with relocations must be real!");
238 // if the section its in is being droped, drop it
239 if (Section->Number == -1)
242 // if it is the section symbol, keep it
243 if (Section->Symbol == this)
246 // if its temporary, drop it
247 if (MCData && MCData->getSymbol().isTemporary())
250 // otherwise, keep it
254 //------------------------------------------------------------------------------
255 // Section class implementation
257 COFFSection::COFFSection(StringRef name)
261 memset(&Header, 0, sizeof(Header));
264 size_t COFFSection::size() {
265 return COFF::SectionSize;
268 //------------------------------------------------------------------------------
269 // StringTable class implementation
271 /// Write the length of the string table into Data.
272 /// The length of the string table includes uint32 length header.
273 void StringTable::update_length() {
274 write_uint32_le(&Data.front(), Data.size());
277 StringTable::StringTable() {
278 // The string table data begins with the length of the entire string table
279 // including the length header. Allocate space for this header.
284 size_t StringTable::size() const {
288 /// Add String to the table iff it is not already there.
289 /// @returns the index into the string table where the string is now located.
290 size_t StringTable::insert(StringRef String) {
291 map::iterator i = Map.find(String);
296 size_t Offset = Data.size();
298 // Insert string data into string table.
299 Data.insert(Data.end(), String.begin(), String.end());
300 Data.push_back('\0');
302 // Put a reference to it in the map.
303 Map[String] = Offset;
305 // Update the internal length field.
311 //------------------------------------------------------------------------------
312 // WinCOFFObjectWriter class implementation
314 WinCOFFObjectWriter::WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
316 : MCObjectWriter(OS, true)
317 , TargetObjectWriter(MOTW) {
318 memset(&Header, 0, sizeof(Header));
320 Header.Machine = TargetObjectWriter->getMachine();
323 WinCOFFObjectWriter::~WinCOFFObjectWriter() {
324 for (symbols::iterator I = Symbols.begin(), E = Symbols.end(); I != E; ++I)
326 for (sections::iterator I = Sections.begin(), E = Sections.end(); I != E; ++I)
330 COFFSymbol *WinCOFFObjectWriter::createSymbol(StringRef Name) {
331 return createCOFFEntity<COFFSymbol>(Name, Symbols);
334 COFFSymbol *WinCOFFObjectWriter::GetOrCreateCOFFSymbol(const MCSymbol * Symbol){
335 symbol_map::iterator i = SymbolMap.find(Symbol);
336 if (i != SymbolMap.end())
338 COFFSymbol *RetSymbol
339 = createCOFFEntity<COFFSymbol>(Symbol->getName(), Symbols);
340 SymbolMap[Symbol] = RetSymbol;
344 COFFSection *WinCOFFObjectWriter::createSection(StringRef Name) {
345 return createCOFFEntity<COFFSection>(Name, Sections);
348 /// A template used to lookup or create a symbol/section, and initialize it if
350 template <typename object_t, typename list_t>
351 object_t *WinCOFFObjectWriter::createCOFFEntity(StringRef Name,
353 object_t *Object = new object_t(Name);
355 List.push_back(Object);
360 /// This function takes a section data object from the assembler
361 /// and creates the associated COFF section staging object.
362 void WinCOFFObjectWriter::DefineSection(MCSectionData const &SectionData) {
363 assert(SectionData.getSection().getVariant() == MCSection::SV_COFF
364 && "Got non COFF section in the COFF backend!");
365 // FIXME: Not sure how to verify this (at least in a debug build).
366 MCSectionCOFF const &Sec =
367 static_cast<MCSectionCOFF const &>(SectionData.getSection());
369 COFFSection *coff_section = createSection(Sec.getSectionName());
370 COFFSymbol *coff_symbol = createSymbol(Sec.getSectionName());
372 coff_section->Symbol = coff_symbol;
373 coff_symbol->Section = coff_section;
374 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC;
376 // In this case the auxiliary symbol is a Section Definition.
377 coff_symbol->Aux.resize(1);
378 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
379 coff_symbol->Aux[0].AuxType = ATSectionDefinition;
380 coff_symbol->Aux[0].Aux.SectionDefinition.Selection = Sec.getSelection();
382 coff_section->Header.Characteristics = Sec.getCharacteristics();
384 uint32_t &Characteristics = coff_section->Header.Characteristics;
385 switch (SectionData.getAlignment()) {
386 case 1: Characteristics |= COFF::IMAGE_SCN_ALIGN_1BYTES; break;
387 case 2: Characteristics |= COFF::IMAGE_SCN_ALIGN_2BYTES; break;
388 case 4: Characteristics |= COFF::IMAGE_SCN_ALIGN_4BYTES; break;
389 case 8: Characteristics |= COFF::IMAGE_SCN_ALIGN_8BYTES; break;
390 case 16: Characteristics |= COFF::IMAGE_SCN_ALIGN_16BYTES; break;
391 case 32: Characteristics |= COFF::IMAGE_SCN_ALIGN_32BYTES; break;
392 case 64: Characteristics |= COFF::IMAGE_SCN_ALIGN_64BYTES; break;
393 case 128: Characteristics |= COFF::IMAGE_SCN_ALIGN_128BYTES; break;
394 case 256: Characteristics |= COFF::IMAGE_SCN_ALIGN_256BYTES; break;
395 case 512: Characteristics |= COFF::IMAGE_SCN_ALIGN_512BYTES; break;
396 case 1024: Characteristics |= COFF::IMAGE_SCN_ALIGN_1024BYTES; break;
397 case 2048: Characteristics |= COFF::IMAGE_SCN_ALIGN_2048BYTES; break;
398 case 4096: Characteristics |= COFF::IMAGE_SCN_ALIGN_4096BYTES; break;
399 case 8192: Characteristics |= COFF::IMAGE_SCN_ALIGN_8192BYTES; break;
401 llvm_unreachable("unsupported section alignment");
404 // Bind internal COFF section to MC section.
405 coff_section->MCData = &SectionData;
406 SectionMap[&SectionData.getSection()] = coff_section;
409 /// This function takes a section data object from the assembler
410 /// and creates the associated COFF symbol staging object.
411 void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
412 MCAssembler &Assembler) {
413 COFFSymbol *coff_symbol = GetOrCreateCOFFSymbol(&SymbolData.getSymbol());
415 coff_symbol->Data.Type = (SymbolData.getFlags() & 0x0000FFFF) >> 0;
416 coff_symbol->Data.StorageClass = (SymbolData.getFlags() & 0x00FF0000) >> 16;
418 if (SymbolData.getFlags() & COFF::SF_WeakExternal) {
419 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
421 if (SymbolData.getSymbol().isVariable()) {
422 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
423 const MCExpr *Value = SymbolData.getSymbol().getVariableValue();
425 // FIXME: This assert message isn't very good.
426 assert(Value->getKind() == MCExpr::SymbolRef &&
427 "Value must be a SymbolRef!");
429 const MCSymbolRefExpr *SymbolRef =
430 static_cast<const MCSymbolRefExpr *>(Value);
431 coff_symbol->Other = GetOrCreateCOFFSymbol(&SymbolRef->getSymbol());
433 std::string WeakName = std::string(".weak.")
434 + SymbolData.getSymbol().getName().str()
436 COFFSymbol *WeakDefault = createSymbol(WeakName);
437 WeakDefault->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
438 WeakDefault->Data.StorageClass = COFF::IMAGE_SYM_CLASS_EXTERNAL;
439 WeakDefault->Data.Type = 0;
440 WeakDefault->Data.Value = 0;
441 coff_symbol->Other = WeakDefault;
444 // Setup the Weak External auxiliary symbol.
445 coff_symbol->Aux.resize(1);
446 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
447 coff_symbol->Aux[0].AuxType = ATWeakExternal;
448 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = 0;
449 coff_symbol->Aux[0].Aux.WeakExternal.Characteristics =
450 COFF::IMAGE_WEAK_EXTERN_SEARCH_LIBRARY;
453 // If no storage class was specified in the streamer, define it here.
454 if (coff_symbol->Data.StorageClass == 0) {
455 bool external = SymbolData.isExternal() || (SymbolData.Fragment == NULL);
457 coff_symbol->Data.StorageClass =
458 external ? COFF::IMAGE_SYM_CLASS_EXTERNAL : COFF::IMAGE_SYM_CLASS_STATIC;
461 if (SymbolData.Fragment != NULL)
462 coff_symbol->Section =
463 SectionMap[&SymbolData.Fragment->getParent()->getSection()];
465 // Bind internal COFF symbol to MC symbol.
466 coff_symbol->MCData = &SymbolData;
467 SymbolMap[&SymbolData.getSymbol()] = coff_symbol;
470 /// making a section real involves assigned it a number and putting
471 /// name into the string table if needed
472 void WinCOFFObjectWriter::MakeSectionReal(COFFSection &S, size_t Number) {
473 if (S.Name.size() > COFF::NameSize) {
474 size_t StringTableEntry = Strings.insert(S.Name.c_str());
476 // FIXME: Why is this number 999999? This number is never mentioned in the
477 // spec. I'm assuming this is due to the printed value needing to fit into
478 // the S.Header.Name field. In which case why not 9999999 (7 9's instead of
479 // 6)? The spec does not state if this entry should be null terminated in
480 // this case, and thus this seems to be the best way to do it. I think I
481 // just solved my own FIXME...
482 if (StringTableEntry > 999999)
483 report_fatal_error("COFF string table is greater than 999999 bytes.");
485 std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry));
487 std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size());
490 S.Symbol->Data.SectionNumber = S.Number;
491 S.Symbol->Aux[0].Aux.SectionDefinition.Number = S.Number;
494 void WinCOFFObjectWriter::MakeSymbolReal(COFFSymbol &S, size_t Index) {
495 if (S.Name.size() > COFF::NameSize) {
496 size_t StringTableEntry = Strings.insert(S.Name.c_str());
498 S.set_name_offset(StringTableEntry);
500 std::memcpy(S.Data.Name, S.Name.c_str(), S.Name.size());
504 bool WinCOFFObjectWriter::ExportSection(COFFSection const *S) {
505 return !S->MCData->getFragmentList().empty();
508 bool WinCOFFObjectWriter::ExportSymbol(MCSymbolData const &SymbolData,
510 // This doesn't seem to be right. Strings referred to from the .data section
511 // need symbols so they can be linked to code in the .text section right?
513 // return Asm.isSymbolLinkerVisible (&SymbolData);
515 // For now, all non-variable symbols are exported,
516 // the linker will sort the rest out for us.
517 return SymbolData.isExternal() || !SymbolData.getSymbol().isVariable();
520 bool WinCOFFObjectWriter::IsPhysicalSection(COFFSection *S) {
521 return (S->Header.Characteristics
522 & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0;
525 //------------------------------------------------------------------------------
526 // entity writing methods
528 void WinCOFFObjectWriter::WriteFileHeader(const COFF::header &Header) {
529 WriteLE16(Header.Machine);
530 WriteLE16(Header.NumberOfSections);
531 WriteLE32(Header.TimeDateStamp);
532 WriteLE32(Header.PointerToSymbolTable);
533 WriteLE32(Header.NumberOfSymbols);
534 WriteLE16(Header.SizeOfOptionalHeader);
535 WriteLE16(Header.Characteristics);
538 void WinCOFFObjectWriter::WriteSymbol(const COFFSymbol *S) {
539 WriteBytes(StringRef(S->Data.Name, COFF::NameSize));
540 WriteLE32(S->Data.Value);
541 WriteLE16(S->Data.SectionNumber);
542 WriteLE16(S->Data.Type);
543 Write8(S->Data.StorageClass);
544 Write8(S->Data.NumberOfAuxSymbols);
545 WriteAuxiliarySymbols(S->Aux);
548 void WinCOFFObjectWriter::WriteAuxiliarySymbols(
549 const COFFSymbol::AuxiliarySymbols &S) {
550 for(COFFSymbol::AuxiliarySymbols::const_iterator i = S.begin(), e = S.end();
553 case ATFunctionDefinition:
554 WriteLE32(i->Aux.FunctionDefinition.TagIndex);
555 WriteLE32(i->Aux.FunctionDefinition.TotalSize);
556 WriteLE32(i->Aux.FunctionDefinition.PointerToLinenumber);
557 WriteLE32(i->Aux.FunctionDefinition.PointerToNextFunction);
558 WriteZeros(sizeof(i->Aux.FunctionDefinition.unused));
560 case ATbfAndefSymbol:
561 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused1));
562 WriteLE16(i->Aux.bfAndefSymbol.Linenumber);
563 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused2));
564 WriteLE32(i->Aux.bfAndefSymbol.PointerToNextFunction);
565 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused3));
568 WriteLE32(i->Aux.WeakExternal.TagIndex);
569 WriteLE32(i->Aux.WeakExternal.Characteristics);
570 WriteZeros(sizeof(i->Aux.WeakExternal.unused));
573 WriteBytes(StringRef(reinterpret_cast<const char *>(i->Aux.File.FileName),
574 sizeof(i->Aux.File.FileName)));
576 case ATSectionDefinition:
577 WriteLE32(i->Aux.SectionDefinition.Length);
578 WriteLE16(i->Aux.SectionDefinition.NumberOfRelocations);
579 WriteLE16(i->Aux.SectionDefinition.NumberOfLinenumbers);
580 WriteLE32(i->Aux.SectionDefinition.CheckSum);
581 WriteLE16(i->Aux.SectionDefinition.Number);
582 Write8(i->Aux.SectionDefinition.Selection);
583 WriteZeros(sizeof(i->Aux.SectionDefinition.unused));
589 void WinCOFFObjectWriter::WriteSectionHeader(const COFF::section &S) {
590 WriteBytes(StringRef(S.Name, COFF::NameSize));
592 WriteLE32(S.VirtualSize);
593 WriteLE32(S.VirtualAddress);
594 WriteLE32(S.SizeOfRawData);
595 WriteLE32(S.PointerToRawData);
596 WriteLE32(S.PointerToRelocations);
597 WriteLE32(S.PointerToLineNumbers);
598 WriteLE16(S.NumberOfRelocations);
599 WriteLE16(S.NumberOfLineNumbers);
600 WriteLE32(S.Characteristics);
603 void WinCOFFObjectWriter::WriteRelocation(const COFF::relocation &R) {
604 WriteLE32(R.VirtualAddress);
605 WriteLE32(R.SymbolTableIndex);
609 ////////////////////////////////////////////////////////////////////////////////
610 // MCObjectWriter interface implementations
612 void WinCOFFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
613 const MCAsmLayout &Layout) {
614 // "Define" each section & symbol. This creates section & symbol
615 // entries in the staging area.
617 for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e; i++)
620 for (MCAssembler::const_symbol_iterator i = Asm.symbol_begin(),
621 e = Asm.symbol_end(); i != e; i++) {
622 if (ExportSymbol(*i, Asm))
623 DefineSymbol(*i, Asm);
627 void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
628 const MCAsmLayout &Layout,
629 const MCFragment *Fragment,
630 const MCFixup &Fixup,
632 uint64_t &FixedValue) {
633 assert(Target.getSymA() != NULL && "Relocation must reference a symbol!");
635 const MCSymbol *A = &Target.getSymA()->getSymbol();
636 MCSymbolData &A_SD = Asm.getSymbolData(*A);
638 MCSectionData const *SectionData = Fragment->getParent();
640 // Mark this symbol as requiring an entry in the symbol table.
641 assert(SectionMap.find(&SectionData->getSection()) != SectionMap.end() &&
642 "Section must already have been defined in ExecutePostLayoutBinding!");
643 assert(SymbolMap.find(&A_SD.getSymbol()) != SymbolMap.end() &&
644 "Symbol must already have been defined in ExecutePostLayoutBinding!");
646 COFFSection *coff_section = SectionMap[&SectionData->getSection()];
647 COFFSymbol *coff_symbol = SymbolMap[&A_SD.getSymbol()];
648 const MCSymbolRefExpr *SymA = Target.getSymA();
649 const MCSymbolRefExpr *SymB = Target.getSymB();
650 const bool CrossSection = SymB &&
651 &SymA->getSymbol().getSection() != &SymB->getSymbol().getSection();
653 if (Target.getSymB()) {
654 const MCSymbol *B = &Target.getSymB()->getSymbol();
655 MCSymbolData &B_SD = Asm.getSymbolData(*B);
657 // Offset of the symbol in the section
658 int64_t a = Layout.getSymbolOffset(&B_SD);
660 // Ofeset of the relocation in the section
661 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
664 // In the case where we have SymbA and SymB, we just need to store the delta
665 // between the two symbols. Update FixedValue to account for the delta, and
666 // skip recording the relocation.
670 FixedValue = Target.getConstant();
673 COFFRelocation Reloc;
675 Reloc.Data.SymbolTableIndex = 0;
676 Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
678 // Turn relocations for temporary symbols into section relocations.
679 if (coff_symbol->MCData->getSymbol().isTemporary() || CrossSection) {
680 Reloc.Symb = coff_symbol->Section->Symbol;
681 FixedValue += Layout.getFragmentOffset(coff_symbol->MCData->Fragment)
682 + coff_symbol->MCData->getOffset();
684 Reloc.Symb = coff_symbol;
686 ++Reloc.Symb->Relocations;
688 Reloc.Data.VirtualAddress += Fixup.getOffset();
690 unsigned FixupKind = Fixup.getKind();
693 FixupKind = FK_PCRel_4;
695 Reloc.Data.Type = TargetObjectWriter->getRelocType(FixupKind);
697 // FIXME: Can anyone explain what this does other than adjust for the size
699 if (Reloc.Data.Type == COFF::IMAGE_REL_AMD64_REL32 ||
700 Reloc.Data.Type == COFF::IMAGE_REL_I386_REL32)
703 coff_section->Relocations.push_back(Reloc);
706 void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
707 const MCAsmLayout &Layout) {
708 // Assign symbol and section indexes and offsets.
709 Header.NumberOfSections = 0;
711 for (sections::iterator i = Sections.begin(),
712 e = Sections.end(); i != e; i++) {
713 if (Layout.getSectionAddressSize((*i)->MCData) > 0) {
714 MakeSectionReal(**i, ++Header.NumberOfSections);
720 Header.NumberOfSymbols = 0;
722 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
723 COFFSymbol *coff_symbol = *i;
724 MCSymbolData const *SymbolData = coff_symbol->MCData;
726 // Update section number & offset for symbols that have them.
727 if ((SymbolData != NULL) && (SymbolData->Fragment != NULL)) {
728 assert(coff_symbol->Section != NULL);
730 coff_symbol->Data.SectionNumber = coff_symbol->Section->Number;
731 coff_symbol->Data.Value = Layout.getFragmentOffset(SymbolData->Fragment)
732 + SymbolData->Offset;
735 if (coff_symbol->should_keep()) {
736 MakeSymbolReal(*coff_symbol, Header.NumberOfSymbols++);
738 // Update auxiliary symbol info.
739 coff_symbol->Data.NumberOfAuxSymbols = coff_symbol->Aux.size();
740 Header.NumberOfSymbols += coff_symbol->Data.NumberOfAuxSymbols;
742 coff_symbol->Index = -1;
745 // Fixup weak external references.
746 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
747 COFFSymbol *coff_symbol = *i;
748 if (coff_symbol->Other != NULL) {
749 assert(coff_symbol->Index != -1);
750 assert(coff_symbol->Aux.size() == 1 &&
751 "Symbol must contain one aux symbol!");
752 assert(coff_symbol->Aux[0].AuxType == ATWeakExternal &&
753 "Symbol's aux symbol must be a Weak External!");
754 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = coff_symbol->Other->Index;
758 // Assign file offsets to COFF object file structures.
762 offset += COFF::HeaderSize;
763 offset += COFF::SectionSize * Header.NumberOfSections;
765 for (MCAssembler::const_iterator i = Asm.begin(),
768 COFFSection *Sec = SectionMap[&i->getSection()];
770 if (Sec->Number == -1)
773 Sec->Header.SizeOfRawData = Layout.getSectionAddressSize(i);
775 if (IsPhysicalSection(Sec)) {
776 Sec->Header.PointerToRawData = offset;
778 offset += Sec->Header.SizeOfRawData;
781 if (Sec->Relocations.size() > 0) {
782 bool RelocationsOverflow = Sec->Relocations.size() >= 0xffff;
784 if (RelocationsOverflow) {
785 // Signal overflow by setting NumberOfSections to max value. Actual
786 // size is found in reloc #0. Microsoft tools understand this.
787 Sec->Header.NumberOfRelocations = 0xffff;
789 Sec->Header.NumberOfRelocations = Sec->Relocations.size();
791 Sec->Header.PointerToRelocations = offset;
793 if (RelocationsOverflow) {
794 // Reloc #0 will contain actual count, so make room for it.
795 offset += COFF::RelocationSize;
798 offset += COFF::RelocationSize * Sec->Relocations.size();
800 for (relocations::iterator cr = Sec->Relocations.begin(),
801 er = Sec->Relocations.end();
803 assert((*cr).Symb->Index != -1);
804 (*cr).Data.SymbolTableIndex = (*cr).Symb->Index;
808 assert(Sec->Symbol->Aux.size() == 1
809 && "Section's symbol must have one aux!");
810 AuxSymbol &Aux = Sec->Symbol->Aux[0];
811 assert(Aux.AuxType == ATSectionDefinition &&
812 "Section's symbol's aux symbol must be a Section Definition!");
813 Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData;
814 Aux.Aux.SectionDefinition.NumberOfRelocations =
815 Sec->Header.NumberOfRelocations;
816 Aux.Aux.SectionDefinition.NumberOfLinenumbers =
817 Sec->Header.NumberOfLineNumbers;
820 Header.PointerToSymbolTable = offset;
822 Header.TimeDateStamp = sys::TimeValue::now().toEpochTime();
824 // Write it all to disk...
825 WriteFileHeader(Header);
828 sections::iterator i, ie;
829 MCAssembler::const_iterator j, je;
831 for (i = Sections.begin(), ie = Sections.end(); i != ie; i++)
832 if ((*i)->Number != -1) {
833 if ((*i)->Relocations.size() >= 0xffff) {
834 (*i)->Header.Characteristics |= COFF::IMAGE_SCN_LNK_NRELOC_OVFL;
836 WriteSectionHeader((*i)->Header);
839 for (i = Sections.begin(), ie = Sections.end(),
840 j = Asm.begin(), je = Asm.end();
841 (i != ie) && (j != je); ++i, ++j) {
843 if ((*i)->Number == -1)
846 if ((*i)->Header.PointerToRawData != 0) {
847 assert(OS.tell() == (*i)->Header.PointerToRawData &&
848 "Section::PointerToRawData is insane!");
850 Asm.writeSectionData(j, Layout);
853 if ((*i)->Relocations.size() > 0) {
854 assert(OS.tell() == (*i)->Header.PointerToRelocations &&
855 "Section::PointerToRelocations is insane!");
857 if ((*i)->Relocations.size() >= 0xffff) {
858 // In case of overflow, write actual relocation count as first
859 // relocation. Including the synthetic reloc itself (+ 1).
861 r.VirtualAddress = (*i)->Relocations.size() + 1;
862 r.SymbolTableIndex = 0;
867 for (relocations::const_iterator k = (*i)->Relocations.begin(),
868 ke = (*i)->Relocations.end();
870 WriteRelocation(k->Data);
873 assert((*i)->Header.PointerToRelocations == 0 &&
874 "Section::PointerToRelocations is insane!");
878 assert(OS.tell() == Header.PointerToSymbolTable &&
879 "Header::PointerToSymbolTable is insane!");
881 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++)
882 if ((*i)->Index != -1)
885 OS.write((char const *)&Strings.Data.front(), Strings.Data.size());
888 MCWinCOFFObjectTargetWriter::MCWinCOFFObjectTargetWriter(unsigned Machine_) :
892 //------------------------------------------------------------------------------
893 // WinCOFFObjectWriter factory function
896 MCObjectWriter *createWinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
898 return new WinCOFFObjectWriter(MOTW, OS);