WinCOFFObjectWriter.cpp revision da0bfcdaf95d95a66e306ef6d45f638939272d34 
1//===-- llvm/MC/WinCOFFObjectWriter.cpp -------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains an implementation of a Win32 COFF object file writer.
11//
12//===----------------------------------------------------------------------===//
13
14#define DEBUG_TYPE "WinCOFFObjectWriter"
15
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"
25
26#include "llvm/ADT/DenseMap.h"
27#include "llvm/ADT/StringMap.h"
28#include "llvm/ADT/StringRef.h"
29
30#include "llvm/Support/COFF.h"
31#include "llvm/Support/Debug.h"
32#include "llvm/Support/ErrorHandling.h"
33
34#include "llvm/System/TimeValue.h"
35
36#include "../Target/X86/X86FixupKinds.h"
37
38#include <cstdio>
39
40using namespace llvm;
41
42namespace {
43typedef llvm::SmallString<COFF::NameSize> name;
44
45enum AuxiliaryType {
46  ATFunctionDefinition,
47  ATbfAndefSymbol,
48  ATWeakExternal,
49  ATFile,
50  ATSectionDefinition
51};
52
53struct AuxSymbol {
54  AuxiliaryType   AuxType;
55  COFF::Auxiliary Aux;
56};
57
58class COFFSymbol {
59public:
60  COFF::symbol Data;
61
62  typedef llvm::SmallVector<AuxSymbol, 1> AuxiliarySymbols;
63
64  name             Name;
65  size_t           Index;
66  AuxiliarySymbols Aux;
67  COFFSymbol      *Other;
68
69  MCSymbolData const *MCData;
70
71  COFFSymbol(llvm::StringRef name, size_t index);
72  size_t size() const;
73  void set_name_offset(uint32_t Offset);
74};
75
76// This class contains staging data for a COFF relocation entry.
77struct COFFRelocation {
78  COFF::relocation Data;
79  COFFSymbol          *Symb;
80
81  COFFRelocation() : Symb(NULL) {}
82  static size_t size() { return COFF::RelocationSize; }
83};
84
85typedef std::vector<COFFRelocation> relocations;
86
87class COFFSection {
88public:
89  COFF::section Header;
90
91  std::string          Name;
92  size_t               Number;
93  MCSectionData const *MCData;
94  COFFSymbol              *Symb;
95  relocations          Relocations;
96
97  COFFSection(llvm::StringRef name, size_t Index);
98  static size_t size();
99};
100
101// This class holds the COFF string table.
102class StringTable {
103  typedef llvm::StringMap<size_t> map;
104  map Map;
105
106  void update_length();
107public:
108  std::vector<char> Data;
109
110  StringTable();
111  size_t size() const;
112  size_t insert(llvm::StringRef String);
113};
114
115class WinCOFFObjectWriter : public MCObjectWriter {
116public:
117
118  typedef std::vector<COFFSymbol*>  symbols;
119  typedef std::vector<COFFSection*> sections;
120
121  typedef StringMap<COFFSymbol *>  name_symbol_map;
122  typedef StringMap<COFFSection *> name_section_map;
123
124  typedef DenseMap<MCSymbolData const *, COFFSymbol *>   symbol_map;
125  typedef DenseMap<MCSectionData const *, COFFSection *> section_map;
126
127  // Root level file contents.
128  COFF::header Header;
129  sections     Sections;
130  symbols      Symbols;
131  StringTable  Strings;
132
133  // Maps used during object file creation.
134  section_map SectionMap;
135  symbol_map  SymbolMap;
136
137  WinCOFFObjectWriter(raw_ostream &OS, bool is64Bit);
138  ~WinCOFFObjectWriter();
139
140  COFFSymbol *createSymbol(llvm::StringRef Name);
141  COFFSection *createSection(llvm::StringRef Name);
142
143  void InitCOFFEntity(COFFSymbol &Symbol);
144  void InitCOFFEntity(COFFSection &Section);
145
146  template <typename object_t, typename list_t>
147  object_t *createCOFFEntity(llvm::StringRef Name, list_t &List);
148
149  void DefineSection(MCSectionData const &SectionData);
150  void DefineSymbol(MCSymbolData const &SymbolData, MCAssembler &Assembler);
151
152  bool ExportSection(COFFSection *S);
153  bool ExportSymbol(MCSymbolData const &SymbolData, MCAssembler &Asm);
154
155  // Entity writing methods.
156
157  void WriteFileHeader(const COFF::header &Header);
158  void WriteSymbol(const COFFSymbol *S);
159  void WriteAuxiliarySymbols(const COFFSymbol::AuxiliarySymbols &S);
160  void WriteSectionHeader(const COFF::section &S);
161  void WriteRelocation(const COFF::relocation &R);
162
163  // MCObjectWriter interface implementation.
164
165  void ExecutePostLayoutBinding(MCAssembler &Asm);
166
167  void RecordRelocation(const MCAssembler &Asm,
168                        const MCAsmLayout &Layout,
169                        const MCFragment *Fragment,
170                        const MCFixup &Fixup,
171                        MCValue Target,
172                        uint64_t &FixedValue);
173
174  void WriteObject(const MCAssembler &Asm, const MCAsmLayout &Layout);
175};
176}
177
178static inline void write_uint32_le(void *Data, uint32_t const &Value) {
179  uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
180  Ptr[0] = (Value & 0x000000FF) >>  0;
181  Ptr[1] = (Value & 0x0000FF00) >>  8;
182  Ptr[2] = (Value & 0x00FF0000) >> 16;
183  Ptr[3] = (Value & 0xFF000000) >> 24;
184}
185
186static inline void write_uint16_le(void *Data, uint16_t const &Value) {
187  uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
188  Ptr[0] = (Value & 0x00FF) >> 0;
189  Ptr[1] = (Value & 0xFF00) >> 8;
190}
191
192static inline void write_uint8_le(void *Data, uint8_t const &Value) {
193  uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
194  Ptr[0] = (Value & 0xFF) >> 0;
195}
196
197//------------------------------------------------------------------------------
198// Symbol class implementation
199
200COFFSymbol::COFFSymbol(llvm::StringRef name, size_t index)
201      : Name(name.begin(), name.end()), Index(-1)
202      , Other(NULL), MCData(NULL) {
203  memset(&Data, 0, sizeof(Data));
204}
205
206size_t COFFSymbol::size() const {
207  return COFF::SymbolSize + (Data.NumberOfAuxSymbols * COFF::SymbolSize);
208}
209
210// In the case that the name does not fit within 8 bytes, the offset
211// into the string table is stored in the last 4 bytes instead, leaving
212// the first 4 bytes as 0.
213void COFFSymbol::set_name_offset(uint32_t Offset) {
214  write_uint32_le(Data.Name + 0, 0);
215  write_uint32_le(Data.Name + 4, Offset);
216}
217
218//------------------------------------------------------------------------------
219// Section class implementation
220
221COFFSection::COFFSection(llvm::StringRef name, size_t Index)
222       : Name(name), Number(Index + 1)
223       , MCData(NULL), Symb(NULL) {
224  memset(&Header, 0, sizeof(Header));
225}
226
227size_t COFFSection::size() {
228  return COFF::SectionSize;
229}
230
231//------------------------------------------------------------------------------
232// StringTable class implementation
233
234/// Write the length of the string table into Data.
235/// The length of the string table includes uint32 length header.
236void StringTable::update_length() {
237  write_uint32_le(&Data.front(), Data.size());
238}
239
240StringTable::StringTable() {
241  // The string table data begins with the length of the entire string table
242  // including the length header. Allocate space for this header.
243  Data.resize(4);
244}
245
246size_t StringTable::size() const {
247  return Data.size();
248}
249
250/// Add String to the table iff it is not already there.
251/// @returns the index into the string table where the string is now located.
252size_t StringTable::insert(llvm::StringRef String) {
253  map::iterator i = Map.find(String);
254
255  if (i != Map.end())
256    return i->second;
257
258  size_t Offset = Data.size();
259
260  // Insert string data into string table.
261  Data.insert(Data.end(), String.begin(), String.end());
262  Data.push_back('\0');
263
264  // Put a reference to it in the map.
265  Map[String] = Offset;
266
267  // Update the internal length field.
268  update_length();
269
270  return Offset;
271}
272
273//------------------------------------------------------------------------------
274// WinCOFFObjectWriter class implementation
275
276WinCOFFObjectWriter::WinCOFFObjectWriter(raw_ostream &OS, bool is64Bit)
277                                : MCObjectWriter(OS, true) {
278  memset(&Header, 0, sizeof(Header));
279
280  is64Bit ? Header.Machine = COFF::IMAGE_FILE_MACHINE_AMD64
281          : Header.Machine = COFF::IMAGE_FILE_MACHINE_I386;
282}
283
284WinCOFFObjectWriter::~WinCOFFObjectWriter() {
285  for (symbols::iterator I = Symbols.begin(), E = Symbols.end(); I != E; ++I)
286    delete *I;
287  for (sections::iterator I = Sections.begin(), E = Sections.end(); I != E; ++I)
288    delete *I;
289}
290
291COFFSymbol *WinCOFFObjectWriter::createSymbol(llvm::StringRef Name) {
292  return createCOFFEntity<COFFSymbol>(Name, Symbols);
293}
294
295COFFSection *WinCOFFObjectWriter::createSection(llvm::StringRef Name) {
296  return createCOFFEntity<COFFSection>(Name, Sections);
297}
298
299/// This function initializes a symbol by entering its name into the string
300/// table if it is too long to fit in the symbol table header.
301void WinCOFFObjectWriter::InitCOFFEntity(COFFSymbol &S) {
302  if (S.Name.size() > COFF::NameSize) {
303    size_t StringTableEntry = Strings.insert(S.Name.c_str());
304
305    S.set_name_offset(StringTableEntry);
306  } else
307    memcpy(S.Data.Name, S.Name.c_str(), S.Name.size());
308}
309
310/// This function initializes a section by entering its name into the string
311/// table if it is too long to fit in the section table header.
312void WinCOFFObjectWriter::InitCOFFEntity(COFFSection &S) {
313  if (S.Name.size() > COFF::NameSize) {
314    size_t StringTableEntry = Strings.insert(S.Name.c_str());
315
316    // FIXME: Why is this number 999999? This number is never mentioned in the
317    // spec. I'm assuming this is due to the printed value needing to fit into
318    // the S.Header.Name field. In which case why not 9999999 (7 9's instead of
319    // 6)? The spec does not state if this entry should be null terminated in
320    // this case, and thus this seems to be the best way to do it. I think I
321    // just solved my own FIXME...
322    if (StringTableEntry > 999999)
323      report_fatal_error("COFF string table is greater than 999999 bytes.");
324
325    sprintf(S.Header.Name, "/%d", (unsigned)StringTableEntry);
326  } else
327    memcpy(S.Header.Name, S.Name.c_str(), S.Name.size());
328}
329
330/// A template used to lookup or create a symbol/section, and initialize it if
331/// needed.
332template <typename object_t, typename list_t>
333object_t *WinCOFFObjectWriter::createCOFFEntity(llvm::StringRef Name,
334                                                list_t &List) {
335  object_t *Object = new object_t(Name, List.size());
336
337  InitCOFFEntity(*Object);
338
339  List.push_back(Object);
340
341  return Object;
342}
343
344/// This function takes a section data object from the assembler
345/// and creates the associated COFF section staging object.
346void WinCOFFObjectWriter::DefineSection(MCSectionData const &SectionData) {
347  // FIXME: Not sure how to verify this (at least in a debug build).
348  MCSectionCOFF const &Sec =
349    static_cast<MCSectionCOFF const &>(SectionData.getSection());
350
351  COFFSection *coff_section = createSection(Sec.getSectionName());
352  COFFSymbol  *coff_symbol = createSymbol(Sec.getSectionName());
353
354  coff_section->Symb = coff_symbol;
355  coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC;
356  coff_symbol->Data.SectionNumber = coff_section->Number;
357
358  // In this case the auxiliary symbol is a Section Definition.
359  coff_symbol->Aux.resize(1);
360  memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
361  coff_symbol->Aux[0].AuxType = ATSectionDefinition;
362  coff_symbol->Aux[0].Aux.SectionDefinition.Number = coff_section->Number;
363  coff_symbol->Aux[0].Aux.SectionDefinition.Selection = Sec.getSelection();
364
365  coff_section->Header.Characteristics = Sec.getCharacteristics();
366
367  uint32_t &Characteristics = coff_section->Header.Characteristics;
368  switch (SectionData.getAlignment()) {
369  case 1:    Characteristics |= COFF::IMAGE_SCN_ALIGN_1BYTES;    break;
370  case 2:    Characteristics |= COFF::IMAGE_SCN_ALIGN_2BYTES;    break;
371  case 4:    Characteristics |= COFF::IMAGE_SCN_ALIGN_4BYTES;    break;
372  case 8:    Characteristics |= COFF::IMAGE_SCN_ALIGN_8BYTES;    break;
373  case 16:   Characteristics |= COFF::IMAGE_SCN_ALIGN_16BYTES;   break;
374  case 32:   Characteristics |= COFF::IMAGE_SCN_ALIGN_32BYTES;   break;
375  case 64:   Characteristics |= COFF::IMAGE_SCN_ALIGN_64BYTES;   break;
376  case 128:  Characteristics |= COFF::IMAGE_SCN_ALIGN_128BYTES;  break;
377  case 256:  Characteristics |= COFF::IMAGE_SCN_ALIGN_256BYTES;  break;
378  case 512:  Characteristics |= COFF::IMAGE_SCN_ALIGN_512BYTES;  break;
379  case 1024: Characteristics |= COFF::IMAGE_SCN_ALIGN_1024BYTES; break;
380  case 2048: Characteristics |= COFF::IMAGE_SCN_ALIGN_2048BYTES; break;
381  case 4096: Characteristics |= COFF::IMAGE_SCN_ALIGN_4096BYTES; break;
382  case 8192: Characteristics |= COFF::IMAGE_SCN_ALIGN_8192BYTES; break;
383  default:
384    llvm_unreachable("unsupported section alignment");
385  }
386
387  // Bind internal COFF section to MC section.
388  coff_section->MCData = &SectionData;
389  SectionMap[&SectionData] = coff_section;
390}
391
392/// This function takes a section data object from the assembler
393/// and creates the associated COFF symbol staging object.
394void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
395                                        MCAssembler &Assembler) {
396  COFFSymbol *coff_symbol = createSymbol(SymbolData.getSymbol().getName());
397
398  coff_symbol->Data.Type         = (SymbolData.getFlags() & 0x0000FFFF) >>  0;
399  coff_symbol->Data.StorageClass = (SymbolData.getFlags() & 0x00FF0000) >> 16;
400
401  // If no storage class was specified in the streamer, define it here.
402  if (coff_symbol->Data.StorageClass == 0) {
403    bool external = SymbolData.isExternal() || (SymbolData.Fragment == NULL);
404
405    coff_symbol->Data.StorageClass =
406      external ? COFF::IMAGE_SYM_CLASS_EXTERNAL : COFF::IMAGE_SYM_CLASS_STATIC;
407  }
408
409  if (SymbolData.getFlags() & COFF::SF_WeakReference) {
410    coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
411
412    const MCExpr *Value = SymbolData.getSymbol().getVariableValue();
413
414    // FIXME: This assert message isn't very good.
415    assert(Value->getKind() == MCExpr::SymbolRef &&
416           "Value must be a SymbolRef!");
417
418    const MCSymbolRefExpr *SymbolRef =
419      static_cast<const MCSymbolRefExpr *>(Value);
420
421    const MCSymbolData &OtherSymbolData =
422      Assembler.getSymbolData(SymbolRef->getSymbol());
423
424    // FIXME: This assert message isn't very good.
425    assert(SymbolMap.find(&OtherSymbolData) != SymbolMap.end() &&
426           "OtherSymbolData must be in the symbol map!");
427
428    coff_symbol->Other = SymbolMap[&OtherSymbolData];
429
430    // Setup the Weak External auxiliary symbol.
431    coff_symbol->Aux.resize(1);
432    memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
433    coff_symbol->Aux[0].AuxType = ATWeakExternal;
434    coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = 0;
435    coff_symbol->Aux[0].Aux.WeakExternal.Characteristics =
436                                        COFF::IMAGE_WEAK_EXTERN_SEARCH_LIBRARY;
437  }
438
439  // Bind internal COFF symbol to MC symbol.
440  coff_symbol->MCData = &SymbolData;
441  SymbolMap[&SymbolData] = coff_symbol;
442}
443
444bool WinCOFFObjectWriter::ExportSection(COFFSection *S) {
445  return (S->Header.Characteristics
446         & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0;
447}
448
449bool WinCOFFObjectWriter::ExportSymbol(MCSymbolData const &SymbolData,
450                                       MCAssembler &Asm) {
451  // This doesn't seem to be right. Strings referred to from the .data section
452  // need symbols so they can be linked to code in the .text section right?
453
454  // return Asm.isSymbolLinkerVisible (&SymbolData);
455
456  // For now, all symbols are exported, the linker will sort it out for us.
457  return true;
458}
459
460//------------------------------------------------------------------------------
461// entity writing methods
462
463void WinCOFFObjectWriter::WriteFileHeader(const COFF::header &Header) {
464  WriteLE16(Header.Machine);
465  WriteLE16(Header.NumberOfSections);
466  WriteLE32(Header.TimeDateStamp);
467  WriteLE32(Header.PointerToSymbolTable);
468  WriteLE32(Header.NumberOfSymbols);
469  WriteLE16(Header.SizeOfOptionalHeader);
470  WriteLE16(Header.Characteristics);
471}
472
473void WinCOFFObjectWriter::WriteSymbol(const COFFSymbol *S) {
474  WriteBytes(StringRef(S->Data.Name, COFF::NameSize));
475  WriteLE32(S->Data.Value);
476  WriteLE16(S->Data.SectionNumber);
477  WriteLE16(S->Data.Type);
478  Write8(S->Data.StorageClass);
479  Write8(S->Data.NumberOfAuxSymbols);
480  WriteAuxiliarySymbols(S->Aux);
481}
482
483void WinCOFFObjectWriter::WriteAuxiliarySymbols(
484                                        const COFFSymbol::AuxiliarySymbols &S) {
485  for(COFFSymbol::AuxiliarySymbols::const_iterator i = S.begin(), e = S.end();
486      i != e; ++i) {
487    switch(i->AuxType) {
488    case ATFunctionDefinition:
489      WriteLE32(i->Aux.FunctionDefinition.TagIndex);
490      WriteLE32(i->Aux.FunctionDefinition.TotalSize);
491      WriteLE32(i->Aux.FunctionDefinition.PointerToLinenumber);
492      WriteLE32(i->Aux.FunctionDefinition.PointerToNextFunction);
493      WriteZeros(sizeof(i->Aux.FunctionDefinition.unused));
494      break;
495    case ATbfAndefSymbol:
496      WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused1));
497      WriteLE16(i->Aux.bfAndefSymbol.Linenumber);
498      WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused2));
499      WriteLE32(i->Aux.bfAndefSymbol.PointerToNextFunction);
500      WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused3));
501      break;
502    case ATWeakExternal:
503      WriteLE32(i->Aux.WeakExternal.TagIndex);
504      WriteLE32(i->Aux.WeakExternal.Characteristics);
505      WriteZeros(sizeof(i->Aux.WeakExternal.unused));
506      break;
507    case ATFile:
508      WriteBytes(StringRef(reinterpret_cast<const char *>(i->Aux.File.FileName),
509                 sizeof(i->Aux.File.FileName)));
510      break;
511    case ATSectionDefinition:
512      WriteLE32(i->Aux.SectionDefinition.Length);
513      WriteLE16(i->Aux.SectionDefinition.NumberOfRelocations);
514      WriteLE16(i->Aux.SectionDefinition.NumberOfLinenumbers);
515      WriteLE32(i->Aux.SectionDefinition.CheckSum);
516      WriteLE16(i->Aux.SectionDefinition.Number);
517      Write8(i->Aux.SectionDefinition.Selection);
518      WriteZeros(sizeof(i->Aux.SectionDefinition.unused));
519      break;
520    }
521  }
522}
523
524void WinCOFFObjectWriter::WriteSectionHeader(const COFF::section &S) {
525  WriteBytes(StringRef(S.Name, COFF::NameSize));
526
527  WriteLE32(S.VirtualSize);
528  WriteLE32(S.VirtualAddress);
529  WriteLE32(S.SizeOfRawData);
530  WriteLE32(S.PointerToRawData);
531  WriteLE32(S.PointerToRelocations);
532  WriteLE32(S.PointerToLineNumbers);
533  WriteLE16(S.NumberOfRelocations);
534  WriteLE16(S.NumberOfLineNumbers);
535  WriteLE32(S.Characteristics);
536}
537
538void WinCOFFObjectWriter::WriteRelocation(const COFF::relocation &R) {
539  WriteLE32(R.VirtualAddress);
540  WriteLE32(R.SymbolTableIndex);
541  WriteLE16(R.Type);
542}
543
544////////////////////////////////////////////////////////////////////////////////
545// MCObjectWriter interface implementations
546
547void WinCOFFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm) {
548  // "Define" each section & symbol. This creates section & symbol
549  // entries in the staging area and gives them their final indexes.
550
551  for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e; i++)
552    DefineSection(*i);
553
554  for (MCAssembler::const_symbol_iterator i = Asm.symbol_begin(),
555                                          e = Asm.symbol_end(); i != e; i++) {
556    if (ExportSymbol(*i, Asm))
557      DefineSymbol(*i, Asm);
558  }
559}
560
561void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
562                                           const MCAsmLayout &Layout,
563                                           const MCFragment *Fragment,
564                                           const MCFixup &Fixup,
565                                           MCValue Target,
566                                           uint64_t &FixedValue) {
567  assert(Target.getSymA() != NULL && "Relocation must reference a symbol!");
568  assert(Target.getSymB() == NULL &&
569         "Relocation must reference only one symbol!");
570
571  MCSectionData const *SectionData = Fragment->getParent();
572  MCSymbolData const *SymbolData =
573                              &Asm.getSymbolData(Target.getSymA()->getSymbol());
574
575  assert(SectionMap.find(SectionData) != SectionMap.end() &&
576         "Section must already have been defined in ExecutePostLayoutBinding!");
577  assert(SymbolMap.find(SymbolData) != SymbolMap.end() &&
578         "Symbol must already have been defined in ExecutePostLayoutBinding!");
579
580  COFFSection *coff_section = SectionMap[SectionData];
581  COFFSymbol *coff_symbol = SymbolMap[SymbolData];
582
583  FixedValue = Target.getConstant();
584
585  COFFRelocation Reloc;
586
587  Reloc.Data.SymbolTableIndex = 0;
588  Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
589  Reloc.Symb = coff_symbol;
590
591  Reloc.Data.VirtualAddress += Fixup.getOffset();
592
593  COFF::RelocationTypeX86 Type;
594
595  if (Header.Machine == COFF::IMAGE_FILE_MACHINE_I386) {
596    switch (Fixup.getKind()) {
597    case X86::reloc_pcrel_4byte:
598      Type = COFF::IMAGE_REL_I386_REL32;
599      FixedValue += 4;
600      break;
601    case FK_Data_4:
602      Type = COFF::IMAGE_REL_I386_DIR32;
603      break;
604    default:
605      llvm_unreachable("unsupported relocation type");
606    }
607  } else if (Header.Machine == COFF::IMAGE_FILE_MACHINE_AMD64) {
608    switch (Fixup.getKind()) {
609    case FK_Data_8:
610      Type = COFF::IMAGE_REL_AMD64_ADDR64;
611      break;
612    case X86::reloc_pcrel_4byte:
613    case X86::reloc_riprel_4byte:
614      Type = COFF::IMAGE_REL_AMD64_REL32;
615      FixedValue += 4;
616      break;
617    case FK_Data_4:
618      Type = COFF::IMAGE_REL_AMD64_ADDR32;
619      break;
620    default:
621      llvm_unreachable("unsupported relocation type");
622    }
623  } else
624    llvm_unreachable("unknown target architecture");
625
626  Reloc.Data.Type = Type;
627
628  coff_section->Relocations.push_back(Reloc);
629}
630
631void WinCOFFObjectWriter::WriteObject(const MCAssembler &Asm,
632                                      const MCAsmLayout &Layout) {
633  // Assign symbol and section indexes and offsets.
634
635  Header.NumberOfSymbols = 0;
636
637  for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
638    COFFSymbol *coff_symbol = *i;
639    MCSymbolData const *SymbolData = coff_symbol->MCData;
640
641    coff_symbol->Index = Header.NumberOfSymbols++;
642
643    // Update section number & offset for symbols that have them.
644    if ((SymbolData != NULL) && (SymbolData->Fragment != NULL)) {
645      COFFSection *coff_section = SectionMap[SymbolData->Fragment->getParent()];
646
647      coff_symbol->Data.SectionNumber = coff_section->Number;
648      coff_symbol->Data.Value = Layout.getFragmentOffset(SymbolData->Fragment)
649                              + SymbolData->Offset;
650    }
651
652    // Update auxiliary symbol info.
653    coff_symbol->Data.NumberOfAuxSymbols = coff_symbol->Aux.size();
654    Header.NumberOfSymbols += coff_symbol->Data.NumberOfAuxSymbols;
655  }
656
657  // Fixup weak external references.
658  for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
659    COFFSymbol *symb = *i;
660
661    if (symb->Other != NULL) {
662      assert(symb->Aux.size() == 1 &&
663             "Symbol must contain one aux symbol!");
664      assert(symb->Aux[0].AuxType == ATWeakExternal &&
665             "Symbol's aux symbol must be a Weak External!");
666      symb->Aux[0].Aux.WeakExternal.TagIndex = symb->Other->Index;
667    }
668  }
669
670  // Assign file offsets to COFF object file structures.
671
672  unsigned offset = 0;
673
674  offset += COFF::HeaderSize;
675  offset += COFF::SectionSize * Asm.size();
676
677  Header.NumberOfSections = Sections.size();
678
679  for (MCAssembler::const_iterator i = Asm.begin(),
680                                   e = Asm.end();
681                                   i != e; i++) {
682    COFFSection *Sec = SectionMap[i];
683
684    Sec->Header.SizeOfRawData = Layout.getSectionFileSize(i);
685
686    if (ExportSection(Sec)) {
687      Sec->Header.PointerToRawData = offset;
688
689      offset += Sec->Header.SizeOfRawData;
690    }
691
692    if (Sec->Relocations.size() > 0) {
693      Sec->Header.NumberOfRelocations = Sec->Relocations.size();
694      Sec->Header.PointerToRelocations = offset;
695
696      offset += COFF::RelocationSize * Sec->Relocations.size();
697
698      for (relocations::iterator cr = Sec->Relocations.begin(),
699                                 er = Sec->Relocations.end();
700                                 cr != er; cr++) {
701        (*cr).Data.SymbolTableIndex = (*cr).Symb->Index;
702      }
703    }
704
705    assert(Sec->Symb->Aux.size() == 1 && "Section's symbol must have one aux!");
706    AuxSymbol &Aux = Sec->Symb->Aux[0];
707    assert(Aux.AuxType == ATSectionDefinition &&
708           "Section's symbol's aux symbol must be a Section Definition!");
709    Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData;
710    Aux.Aux.SectionDefinition.NumberOfRelocations =
711                                                Sec->Header.NumberOfRelocations;
712    Aux.Aux.SectionDefinition.NumberOfLinenumbers =
713                                                Sec->Header.NumberOfLineNumbers;
714  }
715
716  Header.PointerToSymbolTable = offset;
717
718  Header.TimeDateStamp = sys::TimeValue::now().toEpochTime();
719
720  // Write it all to disk...
721  WriteFileHeader(Header);
722
723  {
724    sections::iterator i, ie;
725    MCAssembler::const_iterator j, je;
726
727    for (i = Sections.begin(), ie = Sections.end(); i != ie; i++)
728      WriteSectionHeader((*i)->Header);
729
730    for (i = Sections.begin(), ie = Sections.end(),
731         j = Asm.begin(), je = Asm.end();
732         (i != ie) && (j != je); i++, j++) {
733      if ((*i)->Header.PointerToRawData != 0) {
734        assert(OS.tell() == (*i)->Header.PointerToRawData &&
735               "Section::PointerToRawData is insane!");
736
737        Asm.WriteSectionData(j, Layout, this);
738      }
739
740      if ((*i)->Relocations.size() > 0) {
741        assert(OS.tell() == (*i)->Header.PointerToRelocations &&
742               "Section::PointerToRelocations is insane!");
743
744        for (relocations::const_iterator k = (*i)->Relocations.begin(),
745                                               ke = (*i)->Relocations.end();
746                                               k != ke; k++) {
747          WriteRelocation(k->Data);
748        }
749      } else
750        assert((*i)->Header.PointerToRelocations == 0 &&
751               "Section::PointerToRelocations is insane!");
752    }
753  }
754
755  assert(OS.tell() == Header.PointerToSymbolTable &&
756         "Header::PointerToSymbolTable is insane!");
757
758  for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++)
759    WriteSymbol(*i);
760
761  OS.write((char const *)&Strings.Data.front(), Strings.Data.size());
762}
763
764//------------------------------------------------------------------------------
765// WinCOFFObjectWriter factory function
766
767namespace llvm {
768  MCObjectWriter *createWinCOFFObjectWriter(raw_ostream &OS, bool is64Bit) {
769    return new WinCOFFObjectWriter(OS, is64Bit);
770  }
771}
772