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 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(MCSymbolData const &SymbolData,
414 MCAssembler &Assembler) {
415 MCSymbol const &Symbol = SymbolData.getSymbol();
416 COFFSymbol *coff_symbol = GetOrCreateCOFFSymbol(&Symbol);
417 SymbolMap[&Symbol] = coff_symbol;
419 if (SymbolData.getFlags() & COFF::SF_WeakExternal) {
420 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
422 if (Symbol.isVariable()) {
423 const MCSymbolRefExpr *SymRef =
424 dyn_cast<MCSymbolRefExpr>(Symbol.getVariableValue());
427 report_fatal_error("Weak externals may only alias symbols");
429 coff_symbol->Other = GetOrCreateCOFFSymbol(&SymRef->getSymbol());
431 std::string WeakName = std::string(".weak.")
432 + Symbol.getName().str()
434 COFFSymbol *WeakDefault = createSymbol(WeakName);
435 WeakDefault->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
436 WeakDefault->Data.StorageClass = COFF::IMAGE_SYM_CLASS_EXTERNAL;
437 WeakDefault->Data.Type = 0;
438 WeakDefault->Data.Value = 0;
439 coff_symbol->Other = WeakDefault;
442 // Setup the Weak External auxiliary symbol.
443 coff_symbol->Aux.resize(1);
444 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
445 coff_symbol->Aux[0].AuxType = ATWeakExternal;
446 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = 0;
447 coff_symbol->Aux[0].Aux.WeakExternal.Characteristics =
448 COFF::IMAGE_WEAK_EXTERN_SEARCH_LIBRARY;
450 coff_symbol->MCData = &SymbolData;
452 const MCSymbolData &ResSymData =
453 Assembler.getSymbolData(Symbol.AliasedSymbol());
455 coff_symbol->Data.Type = (ResSymData.getFlags() & 0x0000FFFF) >> 0;
456 coff_symbol->Data.StorageClass = (ResSymData.getFlags() & 0x00FF0000) >> 16;
458 // If no storage class was specified in the streamer, define it here.
459 if (coff_symbol->Data.StorageClass == 0) {
460 bool external = ResSymData.isExternal() || (ResSymData.Fragment == NULL);
462 coff_symbol->Data.StorageClass =
463 external ? COFF::IMAGE_SYM_CLASS_EXTERNAL : COFF::IMAGE_SYM_CLASS_STATIC;
466 if (ResSymData.Fragment != NULL)
467 coff_symbol->Section =
468 SectionMap[&ResSymData.Fragment->getParent()->getSection()];
470 coff_symbol->MCData = &ResSymData;
474 /// making a section real involves assigned it a number and putting
475 /// name into the string table if needed
476 void WinCOFFObjectWriter::MakeSectionReal(COFFSection &S, size_t Number) {
477 if (S.Name.size() > COFF::NameSize) {
478 size_t StringTableEntry = Strings.insert(S.Name.c_str());
480 // FIXME: Why is this number 999999? This number is never mentioned in the
481 // spec. I'm assuming this is due to the printed value needing to fit into
482 // the S.Header.Name field. In which case why not 9999999 (7 9's instead of
483 // 6)? The spec does not state if this entry should be null terminated in
484 // this case, and thus this seems to be the best way to do it. I think I
485 // just solved my own FIXME...
486 if (StringTableEntry > 999999)
487 report_fatal_error("COFF string table is greater than 999999 bytes.");
489 std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry));
491 std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size());
494 S.Symbol->Data.SectionNumber = S.Number;
495 S.Symbol->Aux[0].Aux.SectionDefinition.Number = S.Number;
498 void WinCOFFObjectWriter::MakeSymbolReal(COFFSymbol &S, size_t Index) {
499 if (S.Name.size() > COFF::NameSize) {
500 size_t StringTableEntry = Strings.insert(S.Name.c_str());
502 S.set_name_offset(StringTableEntry);
504 std::memcpy(S.Data.Name, S.Name.c_str(), S.Name.size());
508 bool WinCOFFObjectWriter::ExportSection(COFFSection const *S) {
509 return !S->MCData->getFragmentList().empty();
512 bool WinCOFFObjectWriter::ExportSymbol(MCSymbolData const &SymbolData,
514 // This doesn't seem to be right. Strings referred to from the .data section
515 // need symbols so they can be linked to code in the .text section right?
517 // return Asm.isSymbolLinkerVisible (&SymbolData);
519 // For now, all non-variable symbols are exported,
520 // the linker will sort the rest out for us.
521 return SymbolData.isExternal() || !SymbolData.getSymbol().isVariable();
524 bool WinCOFFObjectWriter::IsPhysicalSection(COFFSection *S) {
525 return (S->Header.Characteristics
526 & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0;
529 //------------------------------------------------------------------------------
530 // entity writing methods
532 void WinCOFFObjectWriter::WriteFileHeader(const COFF::header &Header) {
533 WriteLE16(Header.Machine);
534 WriteLE16(Header.NumberOfSections);
535 WriteLE32(Header.TimeDateStamp);
536 WriteLE32(Header.PointerToSymbolTable);
537 WriteLE32(Header.NumberOfSymbols);
538 WriteLE16(Header.SizeOfOptionalHeader);
539 WriteLE16(Header.Characteristics);
542 void WinCOFFObjectWriter::WriteSymbol(const COFFSymbol *S) {
543 WriteBytes(StringRef(S->Data.Name, COFF::NameSize));
544 WriteLE32(S->Data.Value);
545 WriteLE16(S->Data.SectionNumber);
546 WriteLE16(S->Data.Type);
547 Write8(S->Data.StorageClass);
548 Write8(S->Data.NumberOfAuxSymbols);
549 WriteAuxiliarySymbols(S->Aux);
552 void WinCOFFObjectWriter::WriteAuxiliarySymbols(
553 const COFFSymbol::AuxiliarySymbols &S) {
554 for(COFFSymbol::AuxiliarySymbols::const_iterator i = S.begin(), e = S.end();
557 case ATFunctionDefinition:
558 WriteLE32(i->Aux.FunctionDefinition.TagIndex);
559 WriteLE32(i->Aux.FunctionDefinition.TotalSize);
560 WriteLE32(i->Aux.FunctionDefinition.PointerToLinenumber);
561 WriteLE32(i->Aux.FunctionDefinition.PointerToNextFunction);
562 WriteZeros(sizeof(i->Aux.FunctionDefinition.unused));
564 case ATbfAndefSymbol:
565 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused1));
566 WriteLE16(i->Aux.bfAndefSymbol.Linenumber);
567 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused2));
568 WriteLE32(i->Aux.bfAndefSymbol.PointerToNextFunction);
569 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused3));
572 WriteLE32(i->Aux.WeakExternal.TagIndex);
573 WriteLE32(i->Aux.WeakExternal.Characteristics);
574 WriteZeros(sizeof(i->Aux.WeakExternal.unused));
577 WriteBytes(StringRef(reinterpret_cast<const char *>(i->Aux.File.FileName),
578 sizeof(i->Aux.File.FileName)));
580 case ATSectionDefinition:
581 WriteLE32(i->Aux.SectionDefinition.Length);
582 WriteLE16(i->Aux.SectionDefinition.NumberOfRelocations);
583 WriteLE16(i->Aux.SectionDefinition.NumberOfLinenumbers);
584 WriteLE32(i->Aux.SectionDefinition.CheckSum);
585 WriteLE16(i->Aux.SectionDefinition.Number);
586 Write8(i->Aux.SectionDefinition.Selection);
587 WriteZeros(sizeof(i->Aux.SectionDefinition.unused));
593 void WinCOFFObjectWriter::WriteSectionHeader(const COFF::section &S) {
594 WriteBytes(StringRef(S.Name, COFF::NameSize));
596 WriteLE32(S.VirtualSize);
597 WriteLE32(S.VirtualAddress);
598 WriteLE32(S.SizeOfRawData);
599 WriteLE32(S.PointerToRawData);
600 WriteLE32(S.PointerToRelocations);
601 WriteLE32(S.PointerToLineNumbers);
602 WriteLE16(S.NumberOfRelocations);
603 WriteLE16(S.NumberOfLineNumbers);
604 WriteLE32(S.Characteristics);
607 void WinCOFFObjectWriter::WriteRelocation(const COFF::relocation &R) {
608 WriteLE32(R.VirtualAddress);
609 WriteLE32(R.SymbolTableIndex);
613 ////////////////////////////////////////////////////////////////////////////////
614 // MCObjectWriter interface implementations
616 void WinCOFFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
617 const MCAsmLayout &Layout) {
618 // "Define" each section & symbol. This creates section & symbol
619 // entries in the staging area.
621 for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e; i++)
624 for (MCAssembler::const_symbol_iterator i = Asm.symbol_begin(),
625 e = Asm.symbol_end(); i != e; i++) {
626 if (ExportSymbol(*i, Asm)) {
627 DefineSymbol(*i, Asm);
632 void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
633 const MCAsmLayout &Layout,
634 const MCFragment *Fragment,
635 const MCFixup &Fixup,
637 uint64_t &FixedValue) {
638 assert(Target.getSymA() != NULL && "Relocation must reference a symbol!");
640 const MCSymbol &Symbol = Target.getSymA()->getSymbol();
641 const MCSymbol &A = Symbol.AliasedSymbol();
642 MCSymbolData &A_SD = Asm.getSymbolData(A);
644 MCSectionData const *SectionData = Fragment->getParent();
646 // Mark this symbol as requiring an entry in the symbol table.
647 assert(SectionMap.find(&SectionData->getSection()) != SectionMap.end() &&
648 "Section must already have been defined in ExecutePostLayoutBinding!");
649 assert(SymbolMap.find(&A_SD.getSymbol()) != SymbolMap.end() &&
650 "Symbol must already have been defined in ExecutePostLayoutBinding!");
652 COFFSection *coff_section = SectionMap[&SectionData->getSection()];
653 COFFSymbol *coff_symbol = SymbolMap[&A_SD.getSymbol()];
654 const MCSymbolRefExpr *SymA = Target.getSymA();
655 const MCSymbolRefExpr *SymB = Target.getSymB();
656 const bool CrossSection = SymB &&
657 &SymA->getSymbol().getSection() != &SymB->getSymbol().getSection();
659 if (Target.getSymB()) {
660 const MCSymbol *B = &Target.getSymB()->getSymbol();
661 MCSymbolData &B_SD = Asm.getSymbolData(*B);
663 // Offset of the symbol in the section
664 int64_t a = Layout.getSymbolOffset(&B_SD);
666 // Ofeset of the relocation in the section
667 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
670 // In the case where we have SymbA and SymB, we just need to store the delta
671 // between the two symbols. Update FixedValue to account for the delta, and
672 // skip recording the relocation.
676 FixedValue = Target.getConstant();
679 COFFRelocation Reloc;
681 Reloc.Data.SymbolTableIndex = 0;
682 Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
684 // Turn relocations for temporary symbols into section relocations.
685 if (coff_symbol->MCData->getSymbol().isTemporary() || CrossSection) {
686 Reloc.Symb = coff_symbol->Section->Symbol;
687 FixedValue += Layout.getFragmentOffset(coff_symbol->MCData->Fragment)
688 + coff_symbol->MCData->getOffset();
690 Reloc.Symb = coff_symbol;
692 ++Reloc.Symb->Relocations;
694 Reloc.Data.VirtualAddress += Fixup.getOffset();
695 Reloc.Data.Type = TargetObjectWriter->getRelocType(Target, Fixup,
698 // FIXME: Can anyone explain what this does other than adjust for the size
700 if (Reloc.Data.Type == COFF::IMAGE_REL_AMD64_REL32 ||
701 Reloc.Data.Type == COFF::IMAGE_REL_I386_REL32)
704 coff_section->Relocations.push_back(Reloc);
707 void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
708 const MCAsmLayout &Layout) {
709 // Assign symbol and section indexes and offsets.
710 Header.NumberOfSections = 0;
712 DenseMap<COFFSection *, uint16_t> SectionIndices;
713 for (sections::iterator i = Sections.begin(),
714 e = Sections.end(); i != e; i++) {
715 if (Layout.getSectionAddressSize((*i)->MCData) > 0) {
716 size_t Number = ++Header.NumberOfSections;
717 SectionIndices[*i] = Number;
718 MakeSectionReal(**i, Number);
724 Header.NumberOfSymbols = 0;
726 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
727 COFFSymbol *coff_symbol = *i;
728 MCSymbolData const *SymbolData = coff_symbol->MCData;
730 // Update section number & offset for symbols that have them.
731 if ((SymbolData != NULL) && (SymbolData->Fragment != NULL)) {
732 assert(coff_symbol->Section != NULL);
734 coff_symbol->Data.SectionNumber = coff_symbol->Section->Number;
735 coff_symbol->Data.Value = Layout.getFragmentOffset(SymbolData->Fragment)
736 + SymbolData->Offset;
739 if (coff_symbol->should_keep()) {
740 MakeSymbolReal(*coff_symbol, Header.NumberOfSymbols++);
742 // Update auxiliary symbol info.
743 coff_symbol->Data.NumberOfAuxSymbols = coff_symbol->Aux.size();
744 Header.NumberOfSymbols += coff_symbol->Data.NumberOfAuxSymbols;
746 coff_symbol->Index = -1;
749 // Fixup weak external references.
750 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
751 COFFSymbol *coff_symbol = *i;
752 if (coff_symbol->Other != NULL) {
753 assert(coff_symbol->Index != -1);
754 assert(coff_symbol->Aux.size() == 1 &&
755 "Symbol must contain one aux symbol!");
756 assert(coff_symbol->Aux[0].AuxType == ATWeakExternal &&
757 "Symbol's aux symbol must be a Weak External!");
758 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = coff_symbol->Other->Index;
762 // Fixup associative COMDAT sections.
763 for (sections::iterator i = Sections.begin(),
764 e = Sections.end(); i != e; i++) {
765 if ((*i)->Symbol->Aux[0].Aux.SectionDefinition.Selection !=
766 COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE)
769 const MCSectionCOFF &MCSec = static_cast<const MCSectionCOFF &>(
770 (*i)->MCData->getSection());
772 COFFSection *Assoc = SectionMap.lookup(MCSec.getAssocSection());
774 report_fatal_error(Twine("Missing associated COMDAT section ") +
775 MCSec.getAssocSection()->getSectionName() +
776 " for section " + MCSec.getSectionName());
779 // Skip this section if the associated section is unused.
780 if (Assoc->Number == -1)
783 (*i)->Symbol->Aux[0].Aux.SectionDefinition.Number = SectionIndices[Assoc];
787 // Assign file offsets to COFF object file structures.
791 offset += COFF::HeaderSize;
792 offset += COFF::SectionSize * Header.NumberOfSections;
794 for (MCAssembler::const_iterator i = Asm.begin(),
797 COFFSection *Sec = SectionMap[&i->getSection()];
799 if (Sec->Number == -1)
802 Sec->Header.SizeOfRawData = Layout.getSectionAddressSize(i);
804 if (IsPhysicalSection(Sec)) {
805 Sec->Header.PointerToRawData = offset;
807 offset += Sec->Header.SizeOfRawData;
810 if (Sec->Relocations.size() > 0) {
811 bool RelocationsOverflow = Sec->Relocations.size() >= 0xffff;
813 if (RelocationsOverflow) {
814 // Signal overflow by setting NumberOfSections to max value. Actual
815 // size is found in reloc #0. Microsoft tools understand this.
816 Sec->Header.NumberOfRelocations = 0xffff;
818 Sec->Header.NumberOfRelocations = Sec->Relocations.size();
820 Sec->Header.PointerToRelocations = offset;
822 if (RelocationsOverflow) {
823 // Reloc #0 will contain actual count, so make room for it.
824 offset += COFF::RelocationSize;
827 offset += COFF::RelocationSize * Sec->Relocations.size();
829 for (relocations::iterator cr = Sec->Relocations.begin(),
830 er = Sec->Relocations.end();
832 assert((*cr).Symb->Index != -1);
833 (*cr).Data.SymbolTableIndex = (*cr).Symb->Index;
837 assert(Sec->Symbol->Aux.size() == 1
838 && "Section's symbol must have one aux!");
839 AuxSymbol &Aux = Sec->Symbol->Aux[0];
840 assert(Aux.AuxType == ATSectionDefinition &&
841 "Section's symbol's aux symbol must be a Section Definition!");
842 Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData;
843 Aux.Aux.SectionDefinition.NumberOfRelocations =
844 Sec->Header.NumberOfRelocations;
845 Aux.Aux.SectionDefinition.NumberOfLinenumbers =
846 Sec->Header.NumberOfLineNumbers;
849 Header.PointerToSymbolTable = offset;
851 Header.TimeDateStamp = sys::TimeValue::now().toEpochTime();
853 // Write it all to disk...
854 WriteFileHeader(Header);
857 sections::iterator i, ie;
858 MCAssembler::const_iterator j, je;
860 for (i = Sections.begin(), ie = Sections.end(); i != ie; i++)
861 if ((*i)->Number != -1) {
862 if ((*i)->Relocations.size() >= 0xffff) {
863 (*i)->Header.Characteristics |= COFF::IMAGE_SCN_LNK_NRELOC_OVFL;
865 WriteSectionHeader((*i)->Header);
868 for (i = Sections.begin(), ie = Sections.end(),
869 j = Asm.begin(), je = Asm.end();
870 (i != ie) && (j != je); ++i, ++j) {
872 if ((*i)->Number == -1)
875 if ((*i)->Header.PointerToRawData != 0) {
876 assert(OS.tell() == (*i)->Header.PointerToRawData &&
877 "Section::PointerToRawData is insane!");
879 Asm.writeSectionData(j, Layout);
882 if ((*i)->Relocations.size() > 0) {
883 assert(OS.tell() == (*i)->Header.PointerToRelocations &&
884 "Section::PointerToRelocations is insane!");
886 if ((*i)->Relocations.size() >= 0xffff) {
887 // In case of overflow, write actual relocation count as first
888 // relocation. Including the synthetic reloc itself (+ 1).
890 r.VirtualAddress = (*i)->Relocations.size() + 1;
891 r.SymbolTableIndex = 0;
896 for (relocations::const_iterator k = (*i)->Relocations.begin(),
897 ke = (*i)->Relocations.end();
899 WriteRelocation(k->Data);
902 assert((*i)->Header.PointerToRelocations == 0 &&
903 "Section::PointerToRelocations is insane!");
907 assert(OS.tell() == Header.PointerToSymbolTable &&
908 "Header::PointerToSymbolTable is insane!");
910 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++)
911 if ((*i)->Index != -1)
914 OS.write((char const *)&Strings.Data.front(), Strings.Data.size());
917 MCWinCOFFObjectTargetWriter::MCWinCOFFObjectTargetWriter(unsigned Machine_) :
921 //------------------------------------------------------------------------------
922 // WinCOFFObjectWriter factory function
925 MCObjectWriter *createWinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW,
927 return new WinCOFFObjectWriter(MOTW, OS);