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/Support/TimeValue.h"
35
36#include "../Target/X86/MCTargetDesc/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;
59class COFFSection;
60
61class COFFSymbol {
62public:
63  COFF::symbol Data;
64
65  typedef llvm::SmallVector<AuxSymbol, 1> AuxiliarySymbols;
66
67  name             Name;
68  int              Index;
69  AuxiliarySymbols Aux;
70  COFFSymbol      *Other;
71  COFFSection     *Section;
72  int              Relocations;
73
74  MCSymbolData const *MCData;
75
76  COFFSymbol(llvm::StringRef name);
77  size_t size() const;
78  void set_name_offset(uint32_t Offset);
79
80  bool should_keep() const;
81};
82
83// This class contains staging data for a COFF relocation entry.
84struct COFFRelocation {
85  COFF::relocation Data;
86  COFFSymbol          *Symb;
87
88  COFFRelocation() : Symb(NULL) {}
89  static size_t size() { return COFF::RelocationSize; }
90};
91
92typedef std::vector<COFFRelocation> relocations;
93
94class COFFSection {
95public:
96  COFF::section Header;
97
98  std::string          Name;
99  int                  Number;
100  MCSectionData const *MCData;
101  COFFSymbol          *Symbol;
102  relocations          Relocations;
103
104  COFFSection(llvm::StringRef name);
105  static size_t size();
106};
107
108// This class holds the COFF string table.
109class StringTable {
110  typedef llvm::StringMap<size_t> map;
111  map Map;
112
113  void update_length();
114public:
115  std::vector<char> Data;
116
117  StringTable();
118  size_t size() const;
119  size_t insert(llvm::StringRef String);
120};
121
122class WinCOFFObjectWriter : public MCObjectWriter {
123public:
124
125  typedef std::vector<COFFSymbol*>  symbols;
126  typedef std::vector<COFFSection*> sections;
127
128  typedef DenseMap<MCSymbol  const *, COFFSymbol *>   symbol_map;
129  typedef DenseMap<MCSection const *, COFFSection *> section_map;
130
131  // Root level file contents.
132  bool Is64Bit;
133  COFF::header Header;
134  sections     Sections;
135  symbols      Symbols;
136  StringTable  Strings;
137
138  // Maps used during object file creation.
139  section_map SectionMap;
140  symbol_map  SymbolMap;
141
142  WinCOFFObjectWriter(raw_ostream &OS, bool is64Bit);
143  ~WinCOFFObjectWriter();
144
145  COFFSymbol *createSymbol(StringRef Name);
146  COFFSymbol *GetOrCreateCOFFSymbol(const MCSymbol * Symbol);
147  COFFSection *createSection(StringRef Name);
148
149  template <typename object_t, typename list_t>
150  object_t *createCOFFEntity(llvm::StringRef Name, list_t &List);
151
152  void DefineSection(MCSectionData const &SectionData);
153  void DefineSymbol(MCSymbolData const &SymbolData, MCAssembler &Assembler);
154
155  void MakeSymbolReal(COFFSymbol &S, size_t Index);
156  void MakeSectionReal(COFFSection &S, size_t Number);
157
158  bool ExportSection(COFFSection const *S);
159  bool ExportSymbol(MCSymbolData const &SymbolData, MCAssembler &Asm);
160
161  bool IsPhysicalSection(COFFSection *S);
162
163  // Entity writing methods.
164
165  void WriteFileHeader(const COFF::header &Header);
166  void WriteSymbol(const COFFSymbol *S);
167  void WriteAuxiliarySymbols(const COFFSymbol::AuxiliarySymbols &S);
168  void WriteSectionHeader(const COFF::section &S);
169  void WriteRelocation(const COFF::relocation &R);
170
171  // MCObjectWriter interface implementation.
172
173  void ExecutePostLayoutBinding(MCAssembler &Asm, const MCAsmLayout &Layout);
174
175  void RecordRelocation(const MCAssembler &Asm,
176                        const MCAsmLayout &Layout,
177                        const MCFragment *Fragment,
178                        const MCFixup &Fixup,
179                        MCValue Target,
180                        uint64_t &FixedValue);
181
182  void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
183};
184}
185
186static inline void write_uint32_le(void *Data, uint32_t const &Value) {
187  uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
188  Ptr[0] = (Value & 0x000000FF) >>  0;
189  Ptr[1] = (Value & 0x0000FF00) >>  8;
190  Ptr[2] = (Value & 0x00FF0000) >> 16;
191  Ptr[3] = (Value & 0xFF000000) >> 24;
192}
193
194static inline void write_uint16_le(void *Data, uint16_t const &Value) {
195  uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
196  Ptr[0] = (Value & 0x00FF) >> 0;
197  Ptr[1] = (Value & 0xFF00) >> 8;
198}
199
200static inline void write_uint8_le(void *Data, uint8_t const &Value) {
201  uint8_t *Ptr = reinterpret_cast<uint8_t *>(Data);
202  Ptr[0] = (Value & 0xFF) >> 0;
203}
204
205//------------------------------------------------------------------------------
206// Symbol class implementation
207
208COFFSymbol::COFFSymbol(llvm::StringRef name)
209  : Name(name.begin(), name.end())
210  , Other(NULL)
211  , Section(NULL)
212  , Relocations(0)
213  , MCData(NULL) {
214  memset(&Data, 0, sizeof(Data));
215}
216
217size_t COFFSymbol::size() const {
218  return COFF::SymbolSize + (Data.NumberOfAuxSymbols * COFF::SymbolSize);
219}
220
221// In the case that the name does not fit within 8 bytes, the offset
222// into the string table is stored in the last 4 bytes instead, leaving
223// the first 4 bytes as 0.
224void COFFSymbol::set_name_offset(uint32_t Offset) {
225  write_uint32_le(Data.Name + 0, 0);
226  write_uint32_le(Data.Name + 4, Offset);
227}
228
229/// logic to decide if the symbol should be reported in the symbol table
230bool COFFSymbol::should_keep() const {
231  // no section means its external, keep it
232  if (Section == NULL)
233    return true;
234
235  // if it has relocations pointing at it, keep it
236  if (Relocations > 0)   {
237    assert(Section->Number != -1 && "Sections with relocations must be real!");
238    return true;
239  }
240
241  // if the section its in is being droped, drop it
242  if (Section->Number == -1)
243      return false;
244
245  // if it is the section symbol, keep it
246  if (Section->Symbol == this)
247    return true;
248
249  // if its temporary, drop it
250  if (MCData && MCData->getSymbol().isTemporary())
251      return false;
252
253  // otherwise, keep it
254  return true;
255}
256
257//------------------------------------------------------------------------------
258// Section class implementation
259
260COFFSection::COFFSection(llvm::StringRef name)
261  : Name(name)
262  , MCData(NULL)
263  , Symbol(NULL) {
264  memset(&Header, 0, sizeof(Header));
265}
266
267size_t COFFSection::size() {
268  return COFF::SectionSize;
269}
270
271//------------------------------------------------------------------------------
272// StringTable class implementation
273
274/// Write the length of the string table into Data.
275/// The length of the string table includes uint32 length header.
276void StringTable::update_length() {
277  write_uint32_le(&Data.front(), Data.size());
278}
279
280StringTable::StringTable() {
281  // The string table data begins with the length of the entire string table
282  // including the length header. Allocate space for this header.
283  Data.resize(4);
284}
285
286size_t StringTable::size() const {
287  return Data.size();
288}
289
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.
292size_t StringTable::insert(llvm::StringRef String) {
293  map::iterator i = Map.find(String);
294
295  if (i != Map.end())
296    return i->second;
297
298  size_t Offset = Data.size();
299
300  // Insert string data into string table.
301  Data.insert(Data.end(), String.begin(), String.end());
302  Data.push_back('\0');
303
304  // Put a reference to it in the map.
305  Map[String] = Offset;
306
307  // Update the internal length field.
308  update_length();
309
310  return Offset;
311}
312
313//------------------------------------------------------------------------------
314// WinCOFFObjectWriter class implementation
315
316WinCOFFObjectWriter::WinCOFFObjectWriter(raw_ostream &OS, bool is64Bit)
317  : MCObjectWriter(OS, true)
318  , Is64Bit(is64Bit) {
319  memset(&Header, 0, sizeof(Header));
320
321  Is64Bit ? Header.Machine = COFF::IMAGE_FILE_MACHINE_AMD64
322          : Header.Machine = COFF::IMAGE_FILE_MACHINE_I386;
323}
324
325WinCOFFObjectWriter::~WinCOFFObjectWriter() {
326  for (symbols::iterator I = Symbols.begin(), E = Symbols.end(); I != E; ++I)
327    delete *I;
328  for (sections::iterator I = Sections.begin(), E = Sections.end(); I != E; ++I)
329    delete *I;
330}
331
332COFFSymbol *WinCOFFObjectWriter::createSymbol(StringRef Name) {
333  return createCOFFEntity<COFFSymbol>(Name, Symbols);
334}
335
336COFFSymbol *WinCOFFObjectWriter::GetOrCreateCOFFSymbol(const MCSymbol * Symbol){
337  symbol_map::iterator i = SymbolMap.find(Symbol);
338  if (i != SymbolMap.end())
339    return i->second;
340  COFFSymbol *RetSymbol
341    = createCOFFEntity<COFFSymbol>(Symbol->getName(), Symbols);
342  SymbolMap[Symbol] = RetSymbol;
343  return RetSymbol;
344}
345
346COFFSection *WinCOFFObjectWriter::createSection(llvm::StringRef Name) {
347  return createCOFFEntity<COFFSection>(Name, Sections);
348}
349
350/// A template used to lookup or create a symbol/section, and initialize it if
351/// needed.
352template <typename object_t, typename list_t>
353object_t *WinCOFFObjectWriter::createCOFFEntity(llvm::StringRef Name,
354                                                list_t &List) {
355  object_t *Object = new object_t(Name);
356
357  List.push_back(Object);
358
359  return Object;
360}
361
362/// This function takes a section data object from the assembler
363/// and creates the associated COFF section staging object.
364void 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());
370
371  COFFSection *coff_section = createSection(Sec.getSectionName());
372  COFFSymbol  *coff_symbol = createSymbol(Sec.getSectionName());
373
374  coff_section->Symbol = coff_symbol;
375  coff_symbol->Section = coff_section;
376  coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC;
377
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();
383
384  coff_section->Header.Characteristics = Sec.getCharacteristics();
385
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;
402  default:
403    llvm_unreachable("unsupported section alignment");
404  }
405
406  // Bind internal COFF section to MC section.
407  coff_section->MCData = &SectionData;
408  SectionMap[&SectionData.getSection()] = coff_section;
409}
410
411/// This function takes a section data object from the assembler
412/// and creates the associated COFF symbol staging object.
413void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
414                                       MCAssembler &Assembler) {
415  COFFSymbol *coff_symbol = GetOrCreateCOFFSymbol(&SymbolData.getSymbol());
416
417  coff_symbol->Data.Type         = (SymbolData.getFlags() & 0x0000FFFF) >>  0;
418  coff_symbol->Data.StorageClass = (SymbolData.getFlags() & 0x00FF0000) >> 16;
419
420  if (SymbolData.getFlags() & COFF::SF_WeakExternal) {
421    coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
422
423    if (SymbolData.getSymbol().isVariable()) {
424      coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL;
425      const MCExpr *Value = SymbolData.getSymbol().getVariableValue();
426
427      // FIXME: This assert message isn't very good.
428      assert(Value->getKind() == MCExpr::SymbolRef &&
429              "Value must be a SymbolRef!");
430
431      const MCSymbolRefExpr *SymbolRef =
432        static_cast<const MCSymbolRefExpr *>(Value);
433      coff_symbol->Other = GetOrCreateCOFFSymbol(&SymbolRef->getSymbol());
434    } else {
435      std::string WeakName = std::string(".weak.")
436                           +  SymbolData.getSymbol().getName().str()
437                           + ".default";
438      COFFSymbol *WeakDefault = createSymbol(WeakName);
439      WeakDefault->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
440      WeakDefault->Data.StorageClass  = COFF::IMAGE_SYM_CLASS_EXTERNAL;
441      WeakDefault->Data.Type          = 0;
442      WeakDefault->Data.Value         = 0;
443      coff_symbol->Other = WeakDefault;
444    }
445
446    // Setup the Weak External auxiliary symbol.
447    coff_symbol->Aux.resize(1);
448    memset(&coff_symbol->Aux[0], 0, sizeof(coff_symbol->Aux[0]));
449    coff_symbol->Aux[0].AuxType = ATWeakExternal;
450    coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = 0;
451    coff_symbol->Aux[0].Aux.WeakExternal.Characteristics =
452      COFF::IMAGE_WEAK_EXTERN_SEARCH_LIBRARY;
453  }
454
455  // If no storage class was specified in the streamer, define it here.
456  if (coff_symbol->Data.StorageClass == 0) {
457    bool external = SymbolData.isExternal() || (SymbolData.Fragment == NULL);
458
459    coff_symbol->Data.StorageClass =
460      external ? COFF::IMAGE_SYM_CLASS_EXTERNAL : COFF::IMAGE_SYM_CLASS_STATIC;
461  }
462
463  if (SymbolData.Fragment != NULL)
464    coff_symbol->Section =
465      SectionMap[&SymbolData.Fragment->getParent()->getSection()];
466
467  // Bind internal COFF symbol to MC symbol.
468  coff_symbol->MCData = &SymbolData;
469  SymbolMap[&SymbolData.getSymbol()] = coff_symbol;
470}
471
472/// making a section real involves assigned it a number and putting
473/// name into the string table if needed
474void WinCOFFObjectWriter::MakeSectionReal(COFFSection &S, size_t Number) {
475  if (S.Name.size() > COFF::NameSize) {
476    size_t StringTableEntry = Strings.insert(S.Name.c_str());
477
478    // FIXME: Why is this number 999999? This number is never mentioned in the
479    // spec. I'm assuming this is due to the printed value needing to fit into
480    // the S.Header.Name field. In which case why not 9999999 (7 9's instead of
481    // 6)? The spec does not state if this entry should be null terminated in
482    // this case, and thus this seems to be the best way to do it. I think I
483    // just solved my own FIXME...
484    if (StringTableEntry > 999999)
485      report_fatal_error("COFF string table is greater than 999999 bytes.");
486
487#if defined(__ANDROID__) || defined(ANDROID)
488    // bionic defines sprintf as __builtin___sprintf_chk, which is not available
489    // in std.
490    sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry));
491#else
492    std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry));
493#endif
494  } else
495    std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size());
496
497  S.Number = Number;
498  S.Symbol->Data.SectionNumber = S.Number;
499  S.Symbol->Aux[0].Aux.SectionDefinition.Number = S.Number;
500}
501
502void WinCOFFObjectWriter::MakeSymbolReal(COFFSymbol &S, size_t Index) {
503  if (S.Name.size() > COFF::NameSize) {
504    size_t StringTableEntry = Strings.insert(S.Name.c_str());
505
506    S.set_name_offset(StringTableEntry);
507  } else
508    std::memcpy(S.Data.Name, S.Name.c_str(), S.Name.size());
509  S.Index = Index;
510}
511
512bool WinCOFFObjectWriter::ExportSection(COFFSection const *S) {
513  return !S->MCData->getFragmentList().empty();
514}
515
516bool WinCOFFObjectWriter::ExportSymbol(MCSymbolData const &SymbolData,
517                                       MCAssembler &Asm) {
518  // This doesn't seem to be right. Strings referred to from the .data section
519  // need symbols so they can be linked to code in the .text section right?
520
521  // return Asm.isSymbolLinkerVisible (&SymbolData);
522
523  // For now, all non-variable symbols are exported,
524  // the linker will sort the rest out for us.
525  return SymbolData.isExternal() || !SymbolData.getSymbol().isVariable();
526}
527
528bool WinCOFFObjectWriter::IsPhysicalSection(COFFSection *S) {
529  return (S->Header.Characteristics
530         & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0;
531}
532
533//------------------------------------------------------------------------------
534// entity writing methods
535
536void WinCOFFObjectWriter::WriteFileHeader(const COFF::header &Header) {
537  WriteLE16(Header.Machine);
538  WriteLE16(Header.NumberOfSections);
539  WriteLE32(Header.TimeDateStamp);
540  WriteLE32(Header.PointerToSymbolTable);
541  WriteLE32(Header.NumberOfSymbols);
542  WriteLE16(Header.SizeOfOptionalHeader);
543  WriteLE16(Header.Characteristics);
544}
545
546void WinCOFFObjectWriter::WriteSymbol(const COFFSymbol *S) {
547  WriteBytes(StringRef(S->Data.Name, COFF::NameSize));
548  WriteLE32(S->Data.Value);
549  WriteLE16(S->Data.SectionNumber);
550  WriteLE16(S->Data.Type);
551  Write8(S->Data.StorageClass);
552  Write8(S->Data.NumberOfAuxSymbols);
553  WriteAuxiliarySymbols(S->Aux);
554}
555
556void WinCOFFObjectWriter::WriteAuxiliarySymbols(
557                                        const COFFSymbol::AuxiliarySymbols &S) {
558  for(COFFSymbol::AuxiliarySymbols::const_iterator i = S.begin(), e = S.end();
559      i != e; ++i) {
560    switch(i->AuxType) {
561    case ATFunctionDefinition:
562      WriteLE32(i->Aux.FunctionDefinition.TagIndex);
563      WriteLE32(i->Aux.FunctionDefinition.TotalSize);
564      WriteLE32(i->Aux.FunctionDefinition.PointerToLinenumber);
565      WriteLE32(i->Aux.FunctionDefinition.PointerToNextFunction);
566      WriteZeros(sizeof(i->Aux.FunctionDefinition.unused));
567      break;
568    case ATbfAndefSymbol:
569      WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused1));
570      WriteLE16(i->Aux.bfAndefSymbol.Linenumber);
571      WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused2));
572      WriteLE32(i->Aux.bfAndefSymbol.PointerToNextFunction);
573      WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused3));
574      break;
575    case ATWeakExternal:
576      WriteLE32(i->Aux.WeakExternal.TagIndex);
577      WriteLE32(i->Aux.WeakExternal.Characteristics);
578      WriteZeros(sizeof(i->Aux.WeakExternal.unused));
579      break;
580    case ATFile:
581      WriteBytes(StringRef(reinterpret_cast<const char *>(i->Aux.File.FileName),
582                 sizeof(i->Aux.File.FileName)));
583      break;
584    case ATSectionDefinition:
585      WriteLE32(i->Aux.SectionDefinition.Length);
586      WriteLE16(i->Aux.SectionDefinition.NumberOfRelocations);
587      WriteLE16(i->Aux.SectionDefinition.NumberOfLinenumbers);
588      WriteLE32(i->Aux.SectionDefinition.CheckSum);
589      WriteLE16(i->Aux.SectionDefinition.Number);
590      Write8(i->Aux.SectionDefinition.Selection);
591      WriteZeros(sizeof(i->Aux.SectionDefinition.unused));
592      break;
593    }
594  }
595}
596
597void WinCOFFObjectWriter::WriteSectionHeader(const COFF::section &S) {
598  WriteBytes(StringRef(S.Name, COFF::NameSize));
599
600  WriteLE32(S.VirtualSize);
601  WriteLE32(S.VirtualAddress);
602  WriteLE32(S.SizeOfRawData);
603  WriteLE32(S.PointerToRawData);
604  WriteLE32(S.PointerToRelocations);
605  WriteLE32(S.PointerToLineNumbers);
606  WriteLE16(S.NumberOfRelocations);
607  WriteLE16(S.NumberOfLineNumbers);
608  WriteLE32(S.Characteristics);
609}
610
611void WinCOFFObjectWriter::WriteRelocation(const COFF::relocation &R) {
612  WriteLE32(R.VirtualAddress);
613  WriteLE32(R.SymbolTableIndex);
614  WriteLE16(R.Type);
615}
616
617////////////////////////////////////////////////////////////////////////////////
618// MCObjectWriter interface implementations
619
620void WinCOFFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
621                                                   const MCAsmLayout &Layout) {
622  // "Define" each section & symbol. This creates section & symbol
623  // entries in the staging area.
624
625  for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e; i++)
626    DefineSection(*i);
627
628  for (MCAssembler::const_symbol_iterator i = Asm.symbol_begin(),
629                                          e = Asm.symbol_end(); i != e; i++) {
630    if (ExportSymbol(*i, Asm))
631      DefineSymbol(*i, Asm);
632  }
633}
634
635void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
636                                           const MCAsmLayout &Layout,
637                                           const MCFragment *Fragment,
638                                           const MCFixup &Fixup,
639                                           MCValue Target,
640                                           uint64_t &FixedValue) {
641  assert(Target.getSymA() != NULL && "Relocation must reference a symbol!");
642
643  const MCSymbol *A = &Target.getSymA()->getSymbol();
644  MCSymbolData &A_SD = Asm.getSymbolData(*A);
645
646  MCSectionData const *SectionData = Fragment->getParent();
647
648  // Mark this symbol as requiring an entry in the symbol table.
649  assert(SectionMap.find(&SectionData->getSection()) != SectionMap.end() &&
650         "Section must already have been defined in ExecutePostLayoutBinding!");
651  assert(SymbolMap.find(&A_SD.getSymbol()) != SymbolMap.end() &&
652         "Symbol must already have been defined in ExecutePostLayoutBinding!");
653
654  COFFSection *coff_section = SectionMap[&SectionData->getSection()];
655  COFFSymbol *coff_symbol = SymbolMap[&A_SD.getSymbol()];
656  const MCSymbolRefExpr *SymA = Target.getSymA();
657  const MCSymbolRefExpr *SymB = Target.getSymB();
658  const bool CrossSection = SymB &&
659    &SymA->getSymbol().getSection() != &SymB->getSymbol().getSection();
660
661  if (Target.getSymB()) {
662    const MCSymbol *B = &Target.getSymB()->getSymbol();
663    MCSymbolData &B_SD = Asm.getSymbolData(*B);
664
665    // Offset of the symbol in the section
666    int64_t a = Layout.getSymbolOffset(&B_SD);
667
668    // Ofeset of the relocation in the section
669    int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
670
671    FixedValue = b - a;
672    // In the case where we have SymbA and SymB, we just need to store the delta
673    // between the two symbols.  Update FixedValue to account for the delta, and
674    // skip recording the relocation.
675    if (!CrossSection)
676      return;
677  } else {
678    FixedValue = Target.getConstant();
679  }
680
681  COFFRelocation Reloc;
682
683  Reloc.Data.SymbolTableIndex = 0;
684  Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
685
686  // Turn relocations for temporary symbols into section relocations.
687  if (coff_symbol->MCData->getSymbol().isTemporary() || CrossSection) {
688    Reloc.Symb = coff_symbol->Section->Symbol;
689    FixedValue += Layout.getFragmentOffset(coff_symbol->MCData->Fragment)
690                + coff_symbol->MCData->getOffset();
691  } else
692    Reloc.Symb = coff_symbol;
693
694  ++Reloc.Symb->Relocations;
695
696  Reloc.Data.VirtualAddress += Fixup.getOffset();
697
698  unsigned FixupKind = Fixup.getKind();
699
700  if (CrossSection)
701    FixupKind = FK_PCRel_4;
702
703  switch (FixupKind) {
704  case FK_PCRel_4:
705  case X86::reloc_riprel_4byte:
706  case X86::reloc_riprel_4byte_movq_load:
707    Reloc.Data.Type = Is64Bit ? COFF::IMAGE_REL_AMD64_REL32
708                              : COFF::IMAGE_REL_I386_REL32;
709    // FIXME: Can anyone explain what this does other than adjust for the size
710    // of the offset?
711    FixedValue += 4;
712    break;
713  case FK_Data_4:
714  case X86::reloc_signed_4byte:
715    Reloc.Data.Type = Is64Bit ? COFF::IMAGE_REL_AMD64_ADDR32
716                              : COFF::IMAGE_REL_I386_DIR32;
717    break;
718  case FK_Data_8:
719    if (Is64Bit)
720      Reloc.Data.Type = COFF::IMAGE_REL_AMD64_ADDR64;
721    else
722      llvm_unreachable("unsupported relocation type");
723    break;
724  default:
725    llvm_unreachable("unsupported relocation type");
726  }
727
728  coff_section->Relocations.push_back(Reloc);
729}
730
731void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
732                                      const MCAsmLayout &Layout) {
733  // Assign symbol and section indexes and offsets.
734  Header.NumberOfSections = 0;
735
736  for (sections::iterator i = Sections.begin(),
737                          e = Sections.end(); i != e; i++) {
738    if (Layout.getSectionAddressSize((*i)->MCData) > 0) {
739      MakeSectionReal(**i, ++Header.NumberOfSections);
740    } else {
741      (*i)->Number = -1;
742    }
743  }
744
745  Header.NumberOfSymbols = 0;
746
747  for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
748    COFFSymbol *coff_symbol = *i;
749    MCSymbolData const *SymbolData = coff_symbol->MCData;
750
751    // Update section number & offset for symbols that have them.
752    if ((SymbolData != NULL) && (SymbolData->Fragment != NULL)) {
753      assert(coff_symbol->Section != NULL);
754
755      coff_symbol->Data.SectionNumber = coff_symbol->Section->Number;
756      coff_symbol->Data.Value = Layout.getFragmentOffset(SymbolData->Fragment)
757                              + SymbolData->Offset;
758    }
759
760    if (coff_symbol->should_keep()) {
761      MakeSymbolReal(*coff_symbol, Header.NumberOfSymbols++);
762
763      // Update auxiliary symbol info.
764      coff_symbol->Data.NumberOfAuxSymbols = coff_symbol->Aux.size();
765      Header.NumberOfSymbols += coff_symbol->Data.NumberOfAuxSymbols;
766    } else
767      coff_symbol->Index = -1;
768  }
769
770  // Fixup weak external references.
771  for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
772    COFFSymbol *coff_symbol = *i;
773    if (coff_symbol->Other != NULL) {
774      assert(coff_symbol->Index != -1);
775      assert(coff_symbol->Aux.size() == 1 &&
776             "Symbol must contain one aux symbol!");
777      assert(coff_symbol->Aux[0].AuxType == ATWeakExternal &&
778             "Symbol's aux symbol must be a Weak External!");
779      coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = coff_symbol->Other->Index;
780    }
781  }
782
783  // Assign file offsets to COFF object file structures.
784
785  unsigned offset = 0;
786
787  offset += COFF::HeaderSize;
788  offset += COFF::SectionSize * Header.NumberOfSections;
789
790  for (MCAssembler::const_iterator i = Asm.begin(),
791                                   e = Asm.end();
792                                   i != e; i++) {
793    COFFSection *Sec = SectionMap[&i->getSection()];
794
795    if (Sec->Number == -1)
796      continue;
797
798    Sec->Header.SizeOfRawData = Layout.getSectionAddressSize(i);
799
800    if (IsPhysicalSection(Sec)) {
801      Sec->Header.PointerToRawData = offset;
802
803      offset += Sec->Header.SizeOfRawData;
804    }
805
806    if (Sec->Relocations.size() > 0) {
807      Sec->Header.NumberOfRelocations = Sec->Relocations.size();
808      Sec->Header.PointerToRelocations = offset;
809
810      offset += COFF::RelocationSize * Sec->Relocations.size();
811
812      for (relocations::iterator cr = Sec->Relocations.begin(),
813                                 er = Sec->Relocations.end();
814                                 cr != er; ++cr) {
815        assert((*cr).Symb->Index != -1);
816        (*cr).Data.SymbolTableIndex = (*cr).Symb->Index;
817      }
818    }
819
820    assert(Sec->Symbol->Aux.size() == 1
821      && "Section's symbol must have one aux!");
822    AuxSymbol &Aux = Sec->Symbol->Aux[0];
823    assert(Aux.AuxType == ATSectionDefinition &&
824           "Section's symbol's aux symbol must be a Section Definition!");
825    Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData;
826    Aux.Aux.SectionDefinition.NumberOfRelocations =
827                                                Sec->Header.NumberOfRelocations;
828    Aux.Aux.SectionDefinition.NumberOfLinenumbers =
829                                                Sec->Header.NumberOfLineNumbers;
830  }
831
832  Header.PointerToSymbolTable = offset;
833
834  Header.TimeDateStamp = sys::TimeValue::now().toEpochTime();
835
836  // Write it all to disk...
837  WriteFileHeader(Header);
838
839  {
840    sections::iterator i, ie;
841    MCAssembler::const_iterator j, je;
842
843    for (i = Sections.begin(), ie = Sections.end(); i != ie; i++)
844      if ((*i)->Number != -1)
845        WriteSectionHeader((*i)->Header);
846
847    for (i = Sections.begin(), ie = Sections.end(),
848         j = Asm.begin(), je = Asm.end();
849         (i != ie) && (j != je); ++i, ++j) {
850
851      if ((*i)->Number == -1)
852        continue;
853
854      if ((*i)->Header.PointerToRawData != 0) {
855        assert(OS.tell() == (*i)->Header.PointerToRawData &&
856               "Section::PointerToRawData is insane!");
857
858        Asm.WriteSectionData(j, Layout);
859      }
860
861      if ((*i)->Relocations.size() > 0) {
862        assert(OS.tell() == (*i)->Header.PointerToRelocations &&
863               "Section::PointerToRelocations is insane!");
864
865        for (relocations::const_iterator k = (*i)->Relocations.begin(),
866                                               ke = (*i)->Relocations.end();
867                                               k != ke; k++) {
868          WriteRelocation(k->Data);
869        }
870      } else
871        assert((*i)->Header.PointerToRelocations == 0 &&
872               "Section::PointerToRelocations is insane!");
873    }
874  }
875
876  assert(OS.tell() == Header.PointerToSymbolTable &&
877         "Header::PointerToSymbolTable is insane!");
878
879  for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++)
880    if ((*i)->Index != -1)
881      WriteSymbol(*i);
882
883  OS.write((char const *)&Strings.Data.front(), Strings.Data.size());
884}
885
886//------------------------------------------------------------------------------
887// WinCOFFObjectWriter factory function
888
889namespace llvm {
890  MCObjectWriter *createWinCOFFObjectWriter(raw_ostream &OS, bool is64Bit) {
891    return new WinCOFFObjectWriter(OS, is64Bit);
892  }
893}
894