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(MCSymbol const &Symbol,
151 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 static inline void write_uint16_le(void *Data, uint16_t const &Value) {
194 uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
195 Ptr[0] = (Value & 0x00FF) >> 0;
196 Ptr[1] = (Value & 0xFF00) >> 8;
199 static inline void write_uint8_le(void *Data, uint8_t const &Value) {
200 uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
201 Ptr[0] = (Value & 0xFF) >> 0;
204 //------------------------------------------------------------------------------
205 // Symbol class implementation
207 COFFSymbol::COFFSymbol(StringRef name)
208 : Name(name.begin(), name.end())
213 memset(&Data, 0, sizeof(Data));
216 size_t COFFSymbol::size() const {
217 return COFF::SymbolSize + (Data.NumberOfAuxSymbols * COFF::SymbolSize);
220 // In the case that the name does not fit within 8 bytes, the offset
221 // into the string table is stored in the last 4 bytes instead, leaving
222 // the first 4 bytes as 0.
223 void COFFSymbol::set_name_offset(uint32_t Offset) {
224 write_uint32_le(Data.Name + 0, 0);
225 write_uint32_le(Data.Name + 4, Offset);
228 /// logic to decide if the symbol should be reported in the symbol table
229 bool COFFSymbol::should_keep() const {
230 // no section means its external, keep it
234 // if it has relocations pointing at it, keep it
235 if (Relocations > 0) {
236 assert(Section->Number != -1 && "Sections with relocations must be real!");
240 // if the section its in is being droped, drop it
241 if (Section->Number == -1)
244 // if it is the section symbol, keep it
245 if (Section->Symbol == this)
248 // if its temporary, drop it
249 if (MCData && MCData->getSymbol().isTemporary())
252 // otherwise, keep it
256 //------------------------------------------------------------------------------
257 // Section class implementation
259 COFFSection::COFFSection(StringRef name)
263 memset(&Header, 0, sizeof(Header));
266 size_t COFFSection::size() {
267 return COFF::SectionSize;
270 //------------------------------------------------------------------------------
271 // StringTable class implementation
273 /// Write the length of the string table into Data.
274 /// The length of the string table includes uint32 length header.
275 void StringTable::update_length() {
276 write_uint32_le(&Data.front(), Data.size());
279 StringTable::StringTable() {
280 // The string table data begins with the length of the entire string table
281 // including the length header. Allocate space for this header.
286 size_t StringTable::size() const {
290 /// Add String to the table iff it is not already there.
291 /// @returns the index into the string table where the string is now located.
292 size_t StringTable::insert(StringRef String) {
293 map::iterator i = Map.find(String);
298 size_t Offset = Data.size();
300 // Insert string data into string table.
301 Data.insert(Data.end(), String.begin(), String.end());
302 Data.push_back('\0');
304 // Put a reference to it in the map.
305 Map[String] = Offset;
307 // Update the internal length field.
313 //------------------------------------------------------------------------------
314 // WinCOFFObjectWriter class implementation
316 WinCOFFObjectWriter::WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
318 : MCObjectWriter(OS, true)
319 , TargetObjectWriter(MOTW) {
320 memset(&Header, 0, sizeof(Header));
322 Header.Machine = TargetObjectWriter->getMachine();
325 WinCOFFObjectWriter::~WinCOFFObjectWriter() {
326 for (symbols::iterator I = Symbols.begin(), E = Symbols.end(); I != E; ++I)
328 for (sections::iterator I = Sections.begin(), E = Sections.end(); I != E; ++I)
332 COFFSymbol *WinCOFFObjectWriter::createSymbol(StringRef Name) {
333 return createCOFFEntity<COFFSymbol>(Name, Symbols);
336 COFFSymbol *WinCOFFObjectWriter::GetOrCreateCOFFSymbol(const MCSymbol * Symbol){
337 symbol_map::iterator i = SymbolMap.find(Symbol);
338 if (i != SymbolMap.end())
340 COFFSymbol *RetSymbol
341 = createCOFFEntity<COFFSymbol>(Symbol->getName(), Symbols);
342 SymbolMap[Symbol] = RetSymbol;
346 COFFSection *WinCOFFObjectWriter::createSection(StringRef Name) {
347 return createCOFFEntity<COFFSection>(Name, Sections);
350 /// A template used to lookup or create a symbol/section, and initialize it if
352 template <typename object_t, typename list_t>
353 object_t *WinCOFFObjectWriter::createCOFFEntity(StringRef Name,
355 object_t *Object = new object_t(Name);
357 List.push_back(Object);
362 /// This function takes a section data object from the assembler
363 /// and creates the associated COFF section staging object.
364 void WinCOFFObjectWriter::DefineSection(MCSectionData const &SectionData) {
365 assert(SectionData.getSection().getVariant() == MCSection::SV_COFF
366 && "Got non COFF section in the COFF backend!");
367 // FIXME: Not sure how to verify this (at least in a debug build).
368 MCSectionCOFF const &Sec =
369 static_cast<MCSectionCOFF const &>(SectionData.getSection());
371 COFFSection *coff_section = createSection(Sec.getSectionName());
372 COFFSymbol *coff_symbol = createSymbol(Sec.getSectionName());
374 coff_section->Symbol = coff_symbol;
375 coff_symbol->Section = coff_section;
376 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC;
378 // In this case the auxiliary symbol is a Section Definition.
379 coff_symbol->Aux.resize(1);
380 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
381 coff_symbol->Aux[0].AuxType = ATSectionDefinition;
382 coff_symbol->Aux[0].Aux.SectionDefinition.Selection = Sec.getSelection();
384 coff_section->Header.Characteristics = Sec.getCharacteristics();
386 uint32_t &Characteristics = coff_section->Header.Characteristics;
387 switch (SectionData.getAlignment()) {
388 case 1: Characteristics |= COFF::IMAGE_SCN_ALIGN_1BYTES; break;
389 case 2: Characteristics |= COFF::IMAGE_SCN_ALIGN_2BYTES; break;
390 case 4: Characteristics |= COFF::IMAGE_SCN_ALIGN_4BYTES; break;
391 case 8: Characteristics |= COFF::IMAGE_SCN_ALIGN_8BYTES; break;
392 case 16: Characteristics |= COFF::IMAGE_SCN_ALIGN_16BYTES; break;
393 case 32: Characteristics |= COFF::IMAGE_SCN_ALIGN_32BYTES; break;
394 case 64: Characteristics |= COFF::IMAGE_SCN_ALIGN_64BYTES; break;
395 case 128: Characteristics |= COFF::IMAGE_SCN_ALIGN_128BYTES; break;
396 case 256: Characteristics |= COFF::IMAGE_SCN_ALIGN_256BYTES; break;
397 case 512: Characteristics |= COFF::IMAGE_SCN_ALIGN_512BYTES; break;
398 case 1024: Characteristics |= COFF::IMAGE_SCN_ALIGN_1024BYTES; break;
399 case 2048: Characteristics |= COFF::IMAGE_SCN_ALIGN_2048BYTES; break;
400 case 4096: Characteristics |= COFF::IMAGE_SCN_ALIGN_4096BYTES; break;
401 case 8192: Characteristics |= COFF::IMAGE_SCN_ALIGN_8192BYTES; break;
403 llvm_unreachable("unsupported section alignment");
406 // Bind internal COFF section to MC section.
407 coff_section->MCData = &SectionData;
408 SectionMap[&SectionData.getSection()] = coff_section;
411 /// This function takes a section data object from the assembler
412 /// and creates the associated COFF symbol staging object.
413 void WinCOFFObjectWriter::DefineSymbol(MCSymbol const &Symbol,
414 MCSymbolData const &SymbolData,
415 MCAssembler &Assembler) {
416 COFFSymbol *coff_symbol = GetOrCreateCOFFSymbol(&Symbol);
418 coff_symbol->Data.Type = (SymbolData.getFlags() & 0x0000FFFF) >> 0;
419 coff_symbol->Data.StorageClass = (SymbolData.getFlags() & 0x00FF0000) >> 16;
421 if (SymbolData.getFlags() & COFF::SF_WeakExternal) {
422 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
424 if (Symbol.isVariable()) {
425 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
427 // FIXME: This assert message isn't very good.
428 assert(Symbol.getVariableValue()->getKind() == MCExpr::SymbolRef &&
429 "Value must be a SymbolRef!");
431 coff_symbol->Other = GetOrCreateCOFFSymbol(&Symbol);
433 std::string WeakName = std::string(".weak.")
434 + Symbol.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[&Symbol] = 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 const MCSymbol &Alias = i->getSymbol();
624 const MCSymbol &Symbol = Alias.AliasedSymbol();
625 DefineSymbol(Alias, Asm.getSymbolData(Symbol), Asm);
630 void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
631 const MCAsmLayout &Layout,
632 const MCFragment *Fragment,
633 const MCFixup &Fixup,
635 uint64_t &FixedValue) {
636 assert(Target.getSymA() != NULL && "Relocation must reference a symbol!");
638 const MCSymbol *A = &Target.getSymA()->getSymbol();
639 MCSymbolData &A_SD = Asm.getSymbolData(*A);
641 MCSectionData const *SectionData = Fragment->getParent();
643 // Mark this symbol as requiring an entry in the symbol table.
644 assert(SectionMap.find(&SectionData->getSection()) != SectionMap.end() &&
645 "Section must already have been defined in ExecutePostLayoutBinding!");
646 assert(SymbolMap.find(&A_SD.getSymbol()) != SymbolMap.end() &&
647 "Symbol must already have been defined in ExecutePostLayoutBinding!");
649 COFFSection *coff_section = SectionMap[&SectionData->getSection()];
650 COFFSymbol *coff_symbol = SymbolMap[&A_SD.getSymbol()];
651 const MCSymbolRefExpr *SymA = Target.getSymA();
652 const MCSymbolRefExpr *SymB = Target.getSymB();
653 const bool CrossSection = SymB &&
654 &SymA->getSymbol().getSection() != &SymB->getSymbol().getSection();
656 if (Target.getSymB()) {
657 const MCSymbol *B = &Target.getSymB()->getSymbol();
658 MCSymbolData &B_SD = Asm.getSymbolData(*B);
660 // Offset of the symbol in the section
661 int64_t a = Layout.getSymbolOffset(&B_SD);
663 // Ofeset of the relocation in the section
664 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
667 // In the case where we have SymbA and SymB, we just need to store the delta
668 // between the two symbols. Update FixedValue to account for the delta, and
669 // skip recording the relocation.
673 FixedValue = Target.getConstant();
676 COFFRelocation Reloc;
678 Reloc.Data.SymbolTableIndex = 0;
679 Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
681 // Turn relocations for temporary symbols into section relocations.
682 if (coff_symbol->MCData->getSymbol().isTemporary() || CrossSection) {
683 Reloc.Symb = coff_symbol->Section->Symbol;
684 FixedValue += Layout.getFragmentOffset(coff_symbol->MCData->Fragment)
685 + coff_symbol->MCData->getOffset();
687 Reloc.Symb = coff_symbol;
689 ++Reloc.Symb->Relocations;
691 Reloc.Data.VirtualAddress += Fixup.getOffset();
693 unsigned FixupKind = Fixup.getKind();
696 FixupKind = FK_PCRel_4;
698 Reloc.Data.Type = TargetObjectWriter->getRelocType(FixupKind);
700 // FIXME: Can anyone explain what this does other than adjust for the size
702 if (Reloc.Data.Type == COFF::IMAGE_REL_AMD64_REL32 ||
703 Reloc.Data.Type == COFF::IMAGE_REL_I386_REL32)
706 coff_section->Relocations.push_back(Reloc);
709 void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
710 const MCAsmLayout &Layout) {
711 // Assign symbol and section indexes and offsets.
712 Header.NumberOfSections = 0;
714 for (sections::iterator i = Sections.begin(),
715 e = Sections.end(); i != e; i++) {
716 if (Layout.getSectionAddressSize((*i)->MCData) > 0) {
717 MakeSectionReal(**i, ++Header.NumberOfSections);
723 Header.NumberOfSymbols = 0;
725 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
726 COFFSymbol *coff_symbol = *i;
727 MCSymbolData const *SymbolData = coff_symbol->MCData;
729 // Update section number & offset for symbols that have them.
730 if ((SymbolData != NULL) && (SymbolData->Fragment != NULL)) {
731 assert(coff_symbol->Section != NULL);
733 coff_symbol->Data.SectionNumber = coff_symbol->Section->Number;
734 coff_symbol->Data.Value = Layout.getFragmentOffset(SymbolData->Fragment)
735 + SymbolData->Offset;
738 if (coff_symbol->should_keep()) {
739 MakeSymbolReal(*coff_symbol, Header.NumberOfSymbols++);
741 // Update auxiliary symbol info.
742 coff_symbol->Data.NumberOfAuxSymbols = coff_symbol->Aux.size();
743 Header.NumberOfSymbols += coff_symbol->Data.NumberOfAuxSymbols;
745 coff_symbol->Index = -1;
748 // Fixup weak external references.
749 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
750 COFFSymbol *coff_symbol = *i;
751 if (coff_symbol->Other != NULL) {
752 assert(coff_symbol->Index != -1);
753 assert(coff_symbol->Aux.size() == 1 &&
754 "Symbol must contain one aux symbol!");
755 assert(coff_symbol->Aux[0].AuxType == ATWeakExternal &&
756 "Symbol's aux symbol must be a Weak External!");
757 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = coff_symbol->Other->Index;
761 // Assign file offsets to COFF object file structures.
765 offset += COFF::HeaderSize;
766 offset += COFF::SectionSize * Header.NumberOfSections;
768 for (MCAssembler::const_iterator i = Asm.begin(),
771 COFFSection *Sec = SectionMap[&i->getSection()];
773 if (Sec->Number == -1)
776 Sec->Header.SizeOfRawData = Layout.getSectionAddressSize(i);
778 if (IsPhysicalSection(Sec)) {
779 Sec->Header.PointerToRawData = offset;
781 offset += Sec->Header.SizeOfRawData;
784 if (Sec->Relocations.size() > 0) {
785 bool RelocationsOverflow = Sec->Relocations.size() >= 0xffff;
787 if (RelocationsOverflow) {
788 // Signal overflow by setting NumberOfSections to max value. Actual
789 // size is found in reloc #0. Microsoft tools understand this.
790 Sec->Header.NumberOfRelocations = 0xffff;
792 Sec->Header.NumberOfRelocations = Sec->Relocations.size();
794 Sec->Header.PointerToRelocations = offset;
796 if (RelocationsOverflow) {
797 // Reloc #0 will contain actual count, so make room for it.
798 offset += COFF::RelocationSize;
801 offset += COFF::RelocationSize * Sec->Relocations.size();
803 for (relocations::iterator cr = Sec->Relocations.begin(),
804 er = Sec->Relocations.end();
806 assert((*cr).Symb->Index != -1);
807 (*cr).Data.SymbolTableIndex = (*cr).Symb->Index;
811 assert(Sec->Symbol->Aux.size() == 1
812 && "Section's symbol must have one aux!");
813 AuxSymbol &Aux = Sec->Symbol->Aux[0];
814 assert(Aux.AuxType == ATSectionDefinition &&
815 "Section's symbol's aux symbol must be a Section Definition!");
816 Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData;
817 Aux.Aux.SectionDefinition.NumberOfRelocations =
818 Sec->Header.NumberOfRelocations;
819 Aux.Aux.SectionDefinition.NumberOfLinenumbers =
820 Sec->Header.NumberOfLineNumbers;
823 Header.PointerToSymbolTable = offset;
825 Header.TimeDateStamp = sys::TimeValue::now().toEpochTime();
827 // Write it all to disk...
828 WriteFileHeader(Header);
831 sections::iterator i, ie;
832 MCAssembler::const_iterator j, je;
834 for (i = Sections.begin(), ie = Sections.end(); i != ie; i++)
835 if ((*i)->Number != -1) {
836 if ((*i)->Relocations.size() >= 0xffff) {
837 (*i)->Header.Characteristics |= COFF::IMAGE_SCN_LNK_NRELOC_OVFL;
839 WriteSectionHeader((*i)->Header);
842 for (i = Sections.begin(), ie = Sections.end(),
843 j = Asm.begin(), je = Asm.end();
844 (i != ie) && (j != je); ++i, ++j) {
846 if ((*i)->Number == -1)
849 if ((*i)->Header.PointerToRawData != 0) {
850 assert(OS.tell() == (*i)->Header.PointerToRawData &&
851 "Section::PointerToRawData is insane!");
853 Asm.writeSectionData(j, Layout);
856 if ((*i)->Relocations.size() > 0) {
857 assert(OS.tell() == (*i)->Header.PointerToRelocations &&
858 "Section::PointerToRelocations is insane!");
860 if ((*i)->Relocations.size() >= 0xffff) {
861 // In case of overflow, write actual relocation count as first
862 // relocation. Including the synthetic reloc itself (+ 1).
864 r.VirtualAddress = (*i)->Relocations.size() + 1;
865 r.SymbolTableIndex = 0;
870 for (relocations::const_iterator k = (*i)->Relocations.begin(),
871 ke = (*i)->Relocations.end();
873 WriteRelocation(k->Data);
876 assert((*i)->Header.PointerToRelocations == 0 &&
877 "Section::PointerToRelocations is insane!");
881 assert(OS.tell() == Header.PointerToSymbolTable &&
882 "Header::PointerToSymbolTable is insane!");
884 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++)
885 if ((*i)->Index != -1)
888 OS.write((char const *)&Strings.Data.front(), Strings.Data.size());
891 MCWinCOFFObjectTargetWriter::MCWinCOFFObjectTargetWriter(unsigned Machine_) :
895 //------------------------------------------------------------------------------
896 // WinCOFFObjectWriter factory function
899 MCObjectWriter *createWinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
901 return new WinCOFFObjectWriter(MOTW, OS);