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/MCObjectWriter.h"
17 #include "llvm/MC/MCSection.h"
18 #include "llvm/MC/MCContext.h"
19 #include "llvm/MC/MCSymbol.h"
20 #include "llvm/MC/MCExpr.h"
21 #include "llvm/MC/MCValue.h"
22 #include "llvm/MC/MCAssembler.h"
23 #include "llvm/MC/MCAsmLayout.h"
24 #include "llvm/MC/MCSectionCOFF.h"
26 #include "llvm/ADT/DenseMap.h"
27 #include "llvm/ADT/StringMap.h"
28 #include "llvm/ADT/StringRef.h"
30 #include "llvm/Support/COFF.h"
31 #include "llvm/Support/Debug.h"
32 #include "llvm/Support/ErrorHandling.h"
34 #include "llvm/Support/TimeValue.h"
36 #include "../Target/X86/MCTargetDesc/X86FixupKinds.h"
43 typedef llvm::SmallString<COFF::NameSize> name;
54 AuxiliaryType AuxType;
65 typedef llvm::SmallVector<AuxSymbol, 1> AuxiliarySymbols;
74 MCSymbolData const *MCData;
76 COFFSymbol(llvm::StringRef name);
78 void set_name_offset(uint32_t Offset);
80 bool should_keep() const;
83 // This class contains staging data for a COFF relocation entry.
84 struct COFFRelocation {
85 COFF::relocation Data;
88 COFFRelocation() : Symb(NULL) {}
89 static size_t size() { return COFF::RelocationSize; }
92 typedef std::vector<COFFRelocation> relocations;
100 MCSectionData const *MCData;
102 relocations Relocations;
104 COFFSection(llvm::StringRef name);
105 static size_t size();
108 // This class holds the COFF string table.
110 typedef llvm::StringMap<size_t> map;
113 void update_length();
115 std::vector<char> Data;
119 size_t insert(llvm::StringRef String);
122 class WinCOFFObjectWriter : public MCObjectWriter {
123 unsigned getRelocType(unsigned FixupKind) const;
127 typedef std::vector<COFFSymbol*> symbols;
128 typedef std::vector<COFFSection*> sections;
130 typedef DenseMap<MCSymbol const *, COFFSymbol *> symbol_map;
131 typedef DenseMap<MCSection const *, COFFSection *> section_map;
133 // Root level file contents.
140 // Maps used during object file creation.
141 section_map SectionMap;
142 symbol_map SymbolMap;
144 WinCOFFObjectWriter(raw_ostream &OS, bool is64Bit);
145 ~WinCOFFObjectWriter();
147 COFFSymbol *createSymbol(StringRef Name);
148 COFFSymbol *GetOrCreateCOFFSymbol(const MCSymbol * Symbol);
149 COFFSection *createSection(StringRef Name);
151 template <typename object_t, typename list_t>
152 object_t *createCOFFEntity(llvm::StringRef Name, list_t &List);
154 void DefineSection(MCSectionData const &SectionData);
155 void DefineSymbol(MCSymbolData const &SymbolData, MCAssembler &Assembler);
157 void MakeSymbolReal(COFFSymbol &S, size_t Index);
158 void MakeSectionReal(COFFSection &S, size_t Number);
160 bool ExportSection(COFFSection const *S);
161 bool ExportSymbol(MCSymbolData const &SymbolData, MCAssembler &Asm);
163 bool IsPhysicalSection(COFFSection *S);
165 // Entity writing methods.
167 void WriteFileHeader(const COFF::header &Header);
168 void WriteSymbol(const COFFSymbol *S);
169 void WriteAuxiliarySymbols(const COFFSymbol::AuxiliarySymbols &S);
170 void WriteSectionHeader(const COFF::section &S);
171 void WriteRelocation(const COFF::relocation &R);
173 // MCObjectWriter interface implementation.
175 void ExecutePostLayoutBinding(MCAssembler &Asm, const MCAsmLayout &Layout);
177 void RecordRelocation(const MCAssembler &Asm,
178 const MCAsmLayout &Layout,
179 const MCFragment *Fragment,
180 const MCFixup &Fixup,
182 uint64_t &FixedValue);
184 void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
188 static inline void write_uint32_le(void *Data, uint32_t const &Value) {
189 uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
190 Ptr[0] = (Value & 0x000000FF) >> 0;
191 Ptr[1] = (Value & 0x0000FF00) >> 8;
192 Ptr[2] = (Value & 0x00FF0000) >> 16;
193 Ptr[3] = (Value & 0xFF000000) >> 24;
196 static inline void write_uint16_le(void *Data, uint16_t const &Value) {
197 uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
198 Ptr[0] = (Value & 0x00FF) >> 0;
199 Ptr[1] = (Value & 0xFF00) >> 8;
202 static inline void write_uint8_le(void *Data, uint8_t const &Value) {
203 uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
204 Ptr[0] = (Value & 0xFF) >> 0;
207 //------------------------------------------------------------------------------
208 // Symbol class implementation
210 COFFSymbol::COFFSymbol(llvm::StringRef name)
211 : Name(name.begin(), name.end())
216 memset(&Data, 0, sizeof(Data));
219 size_t COFFSymbol::size() const {
220 return COFF::SymbolSize + (Data.NumberOfAuxSymbols * COFF::SymbolSize);
223 // In the case that the name does not fit within 8 bytes, the offset
224 // into the string table is stored in the last 4 bytes instead, leaving
225 // the first 4 bytes as 0.
226 void COFFSymbol::set_name_offset(uint32_t Offset) {
227 write_uint32_le(Data.Name + 0, 0);
228 write_uint32_le(Data.Name + 4, Offset);
231 /// logic to decide if the symbol should be reported in the symbol table
232 bool COFFSymbol::should_keep() const {
233 // no section means its external, keep it
237 // if it has relocations pointing at it, keep it
238 if (Relocations > 0) {
239 assert(Section->Number != -1 && "Sections with relocations must be real!");
243 // if the section its in is being droped, drop it
244 if (Section->Number == -1)
247 // if it is the section symbol, keep it
248 if (Section->Symbol == this)
251 // if its temporary, drop it
252 if (MCData && MCData->getSymbol().isTemporary())
255 // otherwise, keep it
259 //------------------------------------------------------------------------------
260 // Section class implementation
262 COFFSection::COFFSection(llvm::StringRef name)
266 memset(&Header, 0, sizeof(Header));
269 size_t COFFSection::size() {
270 return COFF::SectionSize;
273 //------------------------------------------------------------------------------
274 // StringTable class implementation
276 /// Write the length of the string table into Data.
277 /// The length of the string table includes uint32 length header.
278 void StringTable::update_length() {
279 write_uint32_le(&Data.front(), Data.size());
282 StringTable::StringTable() {
283 // The string table data begins with the length of the entire string table
284 // including the length header. Allocate space for this header.
289 size_t StringTable::size() const {
293 /// Add String to the table iff it is not already there.
294 /// @returns the index into the string table where the string is now located.
295 size_t StringTable::insert(llvm::StringRef String) {
296 map::iterator i = Map.find(String);
301 size_t Offset = Data.size();
303 // Insert string data into string table.
304 Data.insert(Data.end(), String.begin(), String.end());
305 Data.push_back('\0');
307 // Put a reference to it in the map.
308 Map[String] = Offset;
310 // Update the internal length field.
316 //------------------------------------------------------------------------------
317 // WinCOFFObjectWriter class implementation
319 WinCOFFObjectWriter::WinCOFFObjectWriter(raw_ostream &OS, bool is64Bit)
320 : MCObjectWriter(OS, true)
322 memset(&Header, 0, sizeof(Header));
324 Is64Bit ? Header.Machine = COFF::IMAGE_FILE_MACHINE_AMD64
325 : Header.Machine = COFF::IMAGE_FILE_MACHINE_I386;
328 WinCOFFObjectWriter::~WinCOFFObjectWriter() {
329 for (symbols::iterator I = Symbols.begin(), E = Symbols.end(); I != E; ++I)
331 for (sections::iterator I = Sections.begin(), E = Sections.end(); I != E; ++I)
335 COFFSymbol *WinCOFFObjectWriter::createSymbol(StringRef Name) {
336 return createCOFFEntity<COFFSymbol>(Name, Symbols);
339 COFFSymbol *WinCOFFObjectWriter::GetOrCreateCOFFSymbol(const MCSymbol * Symbol){
340 symbol_map::iterator i = SymbolMap.find(Symbol);
341 if (i != SymbolMap.end())
343 COFFSymbol *RetSymbol
344 = createCOFFEntity<COFFSymbol>(Symbol->getName(), Symbols);
345 SymbolMap[Symbol] = RetSymbol;
349 COFFSection *WinCOFFObjectWriter::createSection(llvm::StringRef Name) {
350 return createCOFFEntity<COFFSection>(Name, Sections);
353 /// A template used to lookup or create a symbol/section, and initialize it if
355 template <typename object_t, typename list_t>
356 object_t *WinCOFFObjectWriter::createCOFFEntity(llvm::StringRef Name,
358 object_t *Object = new object_t(Name);
360 List.push_back(Object);
365 /// This function takes a section data object from the assembler
366 /// and creates the associated COFF section staging object.
367 void WinCOFFObjectWriter::DefineSection(MCSectionData const &SectionData) {
368 assert(SectionData.getSection().getVariant() == MCSection::SV_COFF
369 && "Got non COFF section in the COFF backend!");
370 // FIXME: Not sure how to verify this (at least in a debug build).
371 MCSectionCOFF const &Sec =
372 static_cast<MCSectionCOFF const &>(SectionData.getSection());
374 COFFSection *coff_section = createSection(Sec.getSectionName());
375 COFFSymbol *coff_symbol = createSymbol(Sec.getSectionName());
377 coff_section->Symbol = coff_symbol;
378 coff_symbol->Section = coff_section;
379 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC;
381 // In this case the auxiliary symbol is a Section Definition.
382 coff_symbol->Aux.resize(1);
383 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
384 coff_symbol->Aux[0].AuxType = ATSectionDefinition;
385 coff_symbol->Aux[0].Aux.SectionDefinition.Selection = Sec.getSelection();
387 coff_section->Header.Characteristics = Sec.getCharacteristics();
389 uint32_t &Characteristics = coff_section->Header.Characteristics;
390 switch (SectionData.getAlignment()) {
391 case 1: Characteristics |= COFF::IMAGE_SCN_ALIGN_1BYTES; break;
392 case 2: Characteristics |= COFF::IMAGE_SCN_ALIGN_2BYTES; break;
393 case 4: Characteristics |= COFF::IMAGE_SCN_ALIGN_4BYTES; break;
394 case 8: Characteristics |= COFF::IMAGE_SCN_ALIGN_8BYTES; break;
395 case 16: Characteristics |= COFF::IMAGE_SCN_ALIGN_16BYTES; break;
396 case 32: Characteristics |= COFF::IMAGE_SCN_ALIGN_32BYTES; break;
397 case 64: Characteristics |= COFF::IMAGE_SCN_ALIGN_64BYTES; break;
398 case 128: Characteristics |= COFF::IMAGE_SCN_ALIGN_128BYTES; break;
399 case 256: Characteristics |= COFF::IMAGE_SCN_ALIGN_256BYTES; break;
400 case 512: Characteristics |= COFF::IMAGE_SCN_ALIGN_512BYTES; break;
401 case 1024: Characteristics |= COFF::IMAGE_SCN_ALIGN_1024BYTES; break;
402 case 2048: Characteristics |= COFF::IMAGE_SCN_ALIGN_2048BYTES; break;
403 case 4096: Characteristics |= COFF::IMAGE_SCN_ALIGN_4096BYTES; break;
404 case 8192: Characteristics |= COFF::IMAGE_SCN_ALIGN_8192BYTES; break;
406 llvm_unreachable("unsupported section alignment");
409 // Bind internal COFF section to MC section.
410 coff_section->MCData = &SectionData;
411 SectionMap[&SectionData.getSection()] = coff_section;
414 /// This function takes a section data object from the assembler
415 /// and creates the associated COFF symbol staging object.
416 void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
417 MCAssembler &Assembler) {
418 COFFSymbol *coff_symbol = GetOrCreateCOFFSymbol(&SymbolData.getSymbol());
420 coff_symbol->Data.Type = (SymbolData.getFlags() & 0x0000FFFF) >> 0;
421 coff_symbol->Data.StorageClass = (SymbolData.getFlags() & 0x00FF0000) >> 16;
423 if (SymbolData.getFlags() & COFF::SF_WeakExternal) {
424 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
426 if (SymbolData.getSymbol().isVariable()) {
427 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
428 const MCExpr *Value = SymbolData.getSymbol().getVariableValue();
430 // FIXME: This assert message isn't very good.
431 assert(Value->getKind() == MCExpr::SymbolRef &&
432 "Value must be a SymbolRef!");
434 const MCSymbolRefExpr *SymbolRef =
435 static_cast<const MCSymbolRefExpr *>(Value);
436 coff_symbol->Other = GetOrCreateCOFFSymbol(&SymbolRef->getSymbol());
438 std::string WeakName = std::string(".weak.")
439 + SymbolData.getSymbol().getName().str()
441 COFFSymbol *WeakDefault = createSymbol(WeakName);
442 WeakDefault->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
443 WeakDefault->Data.StorageClass = COFF::IMAGE_SYM_CLASS_EXTERNAL;
444 WeakDefault->Data.Type = 0;
445 WeakDefault->Data.Value = 0;
446 coff_symbol->Other = WeakDefault;
449 // Setup the Weak External auxiliary symbol.
450 coff_symbol->Aux.resize(1);
451 memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
452 coff_symbol->Aux[0].AuxType = ATWeakExternal;
453 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = 0;
454 coff_symbol->Aux[0].Aux.WeakExternal.Characteristics =
455 COFF::IMAGE_WEAK_EXTERN_SEARCH_LIBRARY;
458 // If no storage class was specified in the streamer, define it here.
459 if (coff_symbol->Data.StorageClass == 0) {
460 bool external = SymbolData.isExternal() || (SymbolData.Fragment == NULL);
462 coff_symbol->Data.StorageClass =
463 external ? COFF::IMAGE_SYM_CLASS_EXTERNAL : COFF::IMAGE_SYM_CLASS_STATIC;
466 if (SymbolData.Fragment != NULL)
467 coff_symbol->Section =
468 SectionMap[&SymbolData.Fragment->getParent()->getSection()];
470 // Bind internal COFF symbol to MC symbol.
471 coff_symbol->MCData = &SymbolData;
472 SymbolMap[&SymbolData.getSymbol()] = coff_symbol;
475 /// making a section real involves assigned it a number and putting
476 /// name into the string table if needed
477 void WinCOFFObjectWriter::MakeSectionReal(COFFSection &S, size_t Number) {
478 if (S.Name.size() > COFF::NameSize) {
479 size_t StringTableEntry = Strings.insert(S.Name.c_str());
481 // FIXME: Why is this number 999999? This number is never mentioned in the
482 // spec. I'm assuming this is due to the printed value needing to fit into
483 // the S.Header.Name field. In which case why not 9999999 (7 9's instead of
484 // 6)? The spec does not state if this entry should be null terminated in
485 // this case, and thus this seems to be the best way to do it. I think I
486 // just solved my own FIXME...
487 if (StringTableEntry > 999999)
488 report_fatal_error("COFF string table is greater than 999999 bytes.");
490 std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry));
492 std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size());
495 S.Symbol->Data.SectionNumber = S.Number;
496 S.Symbol->Aux[0].Aux.SectionDefinition.Number = S.Number;
499 void WinCOFFObjectWriter::MakeSymbolReal(COFFSymbol &S, size_t Index) {
500 if (S.Name.size() > COFF::NameSize) {
501 size_t StringTableEntry = Strings.insert(S.Name.c_str());
503 S.set_name_offset(StringTableEntry);
505 std::memcpy(S.Data.Name, S.Name.c_str(), S.Name.size());
509 bool WinCOFFObjectWriter::ExportSection(COFFSection const *S) {
510 return !S->MCData->getFragmentList().empty();
513 bool WinCOFFObjectWriter::ExportSymbol(MCSymbolData const &SymbolData,
515 // This doesn't seem to be right. Strings referred to from the .data section
516 // need symbols so they can be linked to code in the .text section right?
518 // return Asm.isSymbolLinkerVisible (&SymbolData);
520 // For now, all non-variable symbols are exported,
521 // the linker will sort the rest out for us.
522 return SymbolData.isExternal() || !SymbolData.getSymbol().isVariable();
525 bool WinCOFFObjectWriter::IsPhysicalSection(COFFSection *S) {
526 return (S->Header.Characteristics
527 & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0;
530 //------------------------------------------------------------------------------
531 // entity writing methods
533 void WinCOFFObjectWriter::WriteFileHeader(const COFF::header &Header) {
534 WriteLE16(Header.Machine);
535 WriteLE16(Header.NumberOfSections);
536 WriteLE32(Header.TimeDateStamp);
537 WriteLE32(Header.PointerToSymbolTable);
538 WriteLE32(Header.NumberOfSymbols);
539 WriteLE16(Header.SizeOfOptionalHeader);
540 WriteLE16(Header.Characteristics);
543 void WinCOFFObjectWriter::WriteSymbol(const COFFSymbol *S) {
544 WriteBytes(StringRef(S->Data.Name, COFF::NameSize));
545 WriteLE32(S->Data.Value);
546 WriteLE16(S->Data.SectionNumber);
547 WriteLE16(S->Data.Type);
548 Write8(S->Data.StorageClass);
549 Write8(S->Data.NumberOfAuxSymbols);
550 WriteAuxiliarySymbols(S->Aux);
553 void WinCOFFObjectWriter::WriteAuxiliarySymbols(
554 const COFFSymbol::AuxiliarySymbols &S) {
555 for(COFFSymbol::AuxiliarySymbols::const_iterator i = S.begin(), e = S.end();
558 case ATFunctionDefinition:
559 WriteLE32(i->Aux.FunctionDefinition.TagIndex);
560 WriteLE32(i->Aux.FunctionDefinition.TotalSize);
561 WriteLE32(i->Aux.FunctionDefinition.PointerToLinenumber);
562 WriteLE32(i->Aux.FunctionDefinition.PointerToNextFunction);
563 WriteZeros(sizeof(i->Aux.FunctionDefinition.unused));
565 case ATbfAndefSymbol:
566 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused1));
567 WriteLE16(i->Aux.bfAndefSymbol.Linenumber);
568 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused2));
569 WriteLE32(i->Aux.bfAndefSymbol.PointerToNextFunction);
570 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused3));
573 WriteLE32(i->Aux.WeakExternal.TagIndex);
574 WriteLE32(i->Aux.WeakExternal.Characteristics);
575 WriteZeros(sizeof(i->Aux.WeakExternal.unused));
578 WriteBytes(StringRef(reinterpret_cast<const char *>(i->Aux.File.FileName),
579 sizeof(i->Aux.File.FileName)));
581 case ATSectionDefinition:
582 WriteLE32(i->Aux.SectionDefinition.Length);
583 WriteLE16(i->Aux.SectionDefinition.NumberOfRelocations);
584 WriteLE16(i->Aux.SectionDefinition.NumberOfLinenumbers);
585 WriteLE32(i->Aux.SectionDefinition.CheckSum);
586 WriteLE16(i->Aux.SectionDefinition.Number);
587 Write8(i->Aux.SectionDefinition.Selection);
588 WriteZeros(sizeof(i->Aux.SectionDefinition.unused));
594 void WinCOFFObjectWriter::WriteSectionHeader(const COFF::section &S) {
595 WriteBytes(StringRef(S.Name, COFF::NameSize));
597 WriteLE32(S.VirtualSize);
598 WriteLE32(S.VirtualAddress);
599 WriteLE32(S.SizeOfRawData);
600 WriteLE32(S.PointerToRawData);
601 WriteLE32(S.PointerToRelocations);
602 WriteLE32(S.PointerToLineNumbers);
603 WriteLE16(S.NumberOfRelocations);
604 WriteLE16(S.NumberOfLineNumbers);
605 WriteLE32(S.Characteristics);
608 void WinCOFFObjectWriter::WriteRelocation(const COFF::relocation &R) {
609 WriteLE32(R.VirtualAddress);
610 WriteLE32(R.SymbolTableIndex);
614 ////////////////////////////////////////////////////////////////////////////////
615 // MCObjectWriter interface implementations
617 void WinCOFFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
618 const MCAsmLayout &Layout) {
619 // "Define" each section & symbol. This creates section & symbol
620 // entries in the staging area.
622 for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e; i++)
625 for (MCAssembler::const_symbol_iterator i = Asm.symbol_begin(),
626 e = Asm.symbol_end(); i != e; i++) {
627 if (ExportSymbol(*i, Asm))
628 DefineSymbol(*i, Asm);
632 unsigned WinCOFFObjectWriter::getRelocType(unsigned FixupKind) const {
635 case X86::reloc_riprel_4byte:
636 case X86::reloc_riprel_4byte_movq_load:
637 return Is64Bit ? COFF::IMAGE_REL_AMD64_REL32 : COFF::IMAGE_REL_I386_REL32;
640 case X86::reloc_signed_4byte:
641 return Is64Bit ? COFF::IMAGE_REL_AMD64_ADDR32 : COFF::IMAGE_REL_I386_DIR32;
645 return COFF::IMAGE_REL_AMD64_ADDR64;
647 llvm_unreachable("unsupported relocation type");
649 case X86::reloc_coff_secrel32:
650 return Is64Bit ? COFF::IMAGE_REL_AMD64_SREL32 : COFF::IMAGE_REL_I386_SECREL;
653 llvm_unreachable("unsupported relocation type");
658 void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
659 const MCAsmLayout &Layout,
660 const MCFragment *Fragment,
661 const MCFixup &Fixup,
663 uint64_t &FixedValue) {
664 assert(Target.getSymA() != NULL && "Relocation must reference a symbol!");
666 const MCSymbol *A = &Target.getSymA()->getSymbol();
667 MCSymbolData &A_SD = Asm.getSymbolData(*A);
669 MCSectionData const *SectionData = Fragment->getParent();
671 // Mark this symbol as requiring an entry in the symbol table.
672 assert(SectionMap.find(&SectionData->getSection()) != SectionMap.end() &&
673 "Section must already have been defined in ExecutePostLayoutBinding!");
674 assert(SymbolMap.find(&A_SD.getSymbol()) != SymbolMap.end() &&
675 "Symbol must already have been defined in ExecutePostLayoutBinding!");
677 COFFSection *coff_section = SectionMap[&SectionData->getSection()];
678 COFFSymbol *coff_symbol = SymbolMap[&A_SD.getSymbol()];
679 const MCSymbolRefExpr *SymA = Target.getSymA();
680 const MCSymbolRefExpr *SymB = Target.getSymB();
681 const bool CrossSection = SymB &&
682 &SymA->getSymbol().getSection() != &SymB->getSymbol().getSection();
684 if (Target.getSymB()) {
685 const MCSymbol *B = &Target.getSymB()->getSymbol();
686 MCSymbolData &B_SD = Asm.getSymbolData(*B);
688 // Offset of the symbol in the section
689 int64_t a = Layout.getSymbolOffset(&B_SD);
691 // Ofeset of the relocation in the section
692 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
695 // In the case where we have SymbA and SymB, we just need to store the delta
696 // between the two symbols. Update FixedValue to account for the delta, and
697 // skip recording the relocation.
701 FixedValue = Target.getConstant();
704 COFFRelocation Reloc;
706 Reloc.Data.SymbolTableIndex = 0;
707 Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
709 // Turn relocations for temporary symbols into section relocations.
710 if (coff_symbol->MCData->getSymbol().isTemporary() || CrossSection) {
711 Reloc.Symb = coff_symbol->Section->Symbol;
712 FixedValue += Layout.getFragmentOffset(coff_symbol->MCData->Fragment)
713 + coff_symbol->MCData->getOffset();
715 Reloc.Symb = coff_symbol;
717 ++Reloc.Symb->Relocations;
719 Reloc.Data.VirtualAddress += Fixup.getOffset();
721 unsigned FixupKind = Fixup.getKind();
724 FixupKind = FK_PCRel_4;
726 Reloc.Data.Type = getRelocType(FixupKind);
728 // FIXME: Can anyone explain what this does other than adjust for the size
730 if (Reloc.Data.Type == COFF::IMAGE_REL_AMD64_REL32 ||
731 Reloc.Data.Type == COFF::IMAGE_REL_I386_REL32)
734 coff_section->Relocations.push_back(Reloc);
737 void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
738 const MCAsmLayout &Layout) {
739 // Assign symbol and section indexes and offsets.
740 Header.NumberOfSections = 0;
742 for (sections::iterator i = Sections.begin(),
743 e = Sections.end(); i != e; i++) {
744 if (Layout.getSectionAddressSize((*i)->MCData) > 0) {
745 MakeSectionReal(**i, ++Header.NumberOfSections);
751 Header.NumberOfSymbols = 0;
753 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
754 COFFSymbol *coff_symbol = *i;
755 MCSymbolData const *SymbolData = coff_symbol->MCData;
757 // Update section number & offset for symbols that have them.
758 if ((SymbolData != NULL) && (SymbolData->Fragment != NULL)) {
759 assert(coff_symbol->Section != NULL);
761 coff_symbol->Data.SectionNumber = coff_symbol->Section->Number;
762 coff_symbol->Data.Value = Layout.getFragmentOffset(SymbolData->Fragment)
763 + SymbolData->Offset;
766 if (coff_symbol->should_keep()) {
767 MakeSymbolReal(*coff_symbol, Header.NumberOfSymbols++);
769 // Update auxiliary symbol info.
770 coff_symbol->Data.NumberOfAuxSymbols = coff_symbol->Aux.size();
771 Header.NumberOfSymbols += coff_symbol->Data.NumberOfAuxSymbols;
773 coff_symbol->Index = -1;
776 // Fixup weak external references.
777 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
778 COFFSymbol *coff_symbol = *i;
779 if (coff_symbol->Other != NULL) {
780 assert(coff_symbol->Index != -1);
781 assert(coff_symbol->Aux.size() == 1 &&
782 "Symbol must contain one aux symbol!");
783 assert(coff_symbol->Aux[0].AuxType == ATWeakExternal &&
784 "Symbol's aux symbol must be a Weak External!");
785 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = coff_symbol->Other->Index;
789 // Assign file offsets to COFF object file structures.
793 offset += COFF::HeaderSize;
794 offset += COFF::SectionSize * Header.NumberOfSections;
796 for (MCAssembler::const_iterator i = Asm.begin(),
799 COFFSection *Sec = SectionMap[&i->getSection()];
801 if (Sec->Number == -1)
804 Sec->Header.SizeOfRawData = Layout.getSectionAddressSize(i);
806 if (IsPhysicalSection(Sec)) {
807 Sec->Header.PointerToRawData = offset;
809 offset += Sec->Header.SizeOfRawData;
812 if (Sec->Relocations.size() > 0) {
813 Sec->Header.NumberOfRelocations = Sec->Relocations.size();
814 Sec->Header.PointerToRelocations = offset;
816 offset += COFF::RelocationSize * Sec->Relocations.size();
818 for (relocations::iterator cr = Sec->Relocations.begin(),
819 er = Sec->Relocations.end();
821 assert((*cr).Symb->Index != -1);
822 (*cr).Data.SymbolTableIndex = (*cr).Symb->Index;
826 assert(Sec->Symbol->Aux.size() == 1
827 && "Section's symbol must have one aux!");
828 AuxSymbol &Aux = Sec->Symbol->Aux[0];
829 assert(Aux.AuxType == ATSectionDefinition &&
830 "Section's symbol's aux symbol must be a Section Definition!");
831 Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData;
832 Aux.Aux.SectionDefinition.NumberOfRelocations =
833 Sec->Header.NumberOfRelocations;
834 Aux.Aux.SectionDefinition.NumberOfLinenumbers =
835 Sec->Header.NumberOfLineNumbers;
838 Header.PointerToSymbolTable = offset;
840 Header.TimeDateStamp = sys::TimeValue::now().toEpochTime();
842 // Write it all to disk...
843 WriteFileHeader(Header);
846 sections::iterator i, ie;
847 MCAssembler::const_iterator j, je;
849 for (i = Sections.begin(), ie = Sections.end(); i != ie; i++)
850 if ((*i)->Number != -1)
851 WriteSectionHeader((*i)->Header);
853 for (i = Sections.begin(), ie = Sections.end(),
854 j = Asm.begin(), je = Asm.end();
855 (i != ie) && (j != je); ++i, ++j) {
857 if ((*i)->Number == -1)
860 if ((*i)->Header.PointerToRawData != 0) {
861 assert(OS.tell() == (*i)->Header.PointerToRawData &&
862 "Section::PointerToRawData is insane!");
864 Asm.writeSectionData(j, Layout);
867 if ((*i)->Relocations.size() > 0) {
868 assert(OS.tell() == (*i)->Header.PointerToRelocations &&
869 "Section::PointerToRelocations is insane!");
871 for (relocations::const_iterator k = (*i)->Relocations.begin(),
872 ke = (*i)->Relocations.end();
874 WriteRelocation(k->Data);
877 assert((*i)->Header.PointerToRelocations == 0 &&
878 "Section::PointerToRelocations is insane!");
882 assert(OS.tell() == Header.PointerToSymbolTable &&
883 "Header::PointerToSymbolTable is insane!");
885 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++)
886 if ((*i)->Index != -1)
889 OS.write((char const *)&Strings.Data.front(), Strings.Data.size());
892 //------------------------------------------------------------------------------
893 // WinCOFFObjectWriter factory function
896 MCObjectWriter *createWinCOFFObjectWriter(raw_ostream &OS, bool is64Bit) {
897 return new WinCOFFObjectWriter(OS, is64Bit);