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Chris Lattnerb1622902010-07-11 22:07:02 +00001//===-- 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"
Michael J. Spencer801a3592010-07-26 02:17:32 +000015
Chris Lattnerb1622902010-07-11 22:07:02 +000016#include "llvm/MC/MCObjectWriter.h"
Michael J. Spencer801a3592010-07-26 02:17:32 +000017#include "llvm/MC/MCSection.h"
18#include "llvm/MC/MCContext.h"
19#include "llvm/MC/MCSymbol.h"
20#include "llvm/MC/MCExpr.h"
Chris Lattnerb1622902010-07-11 22:07:02 +000021#include "llvm/MC/MCValue.h"
22#include "llvm/MC/MCAssembler.h"
23#include "llvm/MC/MCAsmLayout.h"
Michael J. Spencer801a3592010-07-26 02:17:32 +000024#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
Michael J. Spencer1f6efa32010-11-29 18:16:10 +000034#include "llvm/Support/TimeValue.h"
Michael J. Spencerab3de492010-08-03 04:43:33 +000035
Michael J. Spencerda0bfcd2010-08-21 05:58:13 +000036#include "../Target/X86/X86FixupKinds.h"
37
Michael J. Spencer801a3592010-07-26 02:17:32 +000038#include <cstdio>
39
Chris Lattnerb1622902010-07-11 22:07:02 +000040using namespace llvm;
41
42namespace {
Michael J. Spencer801a3592010-07-26 02:17:32 +000043typedef llvm::SmallString<COFF::NameSize> name;
Chris Lattnerb1622902010-07-11 22:07:02 +000044
Michael J. Spencer801a3592010-07-26 02:17:32 +000045enum AuxiliaryType {
46 ATFunctionDefinition,
47 ATbfAndefSymbol,
48 ATWeakExternal,
49 ATFile,
50 ATSectionDefinition
51};
Chris Lattnerb1622902010-07-11 22:07:02 +000052
Michael J. Spencer801a3592010-07-26 02:17:32 +000053struct AuxSymbol {
54 AuxiliaryType AuxType;
55 COFF::Auxiliary Aux;
56};
Chris Lattnerb1622902010-07-11 22:07:02 +000057
Michael J. Spencera72d8782010-09-27 08:58:26 +000058class COFFSymbol;
59class COFFSection;
60
Michael J. Spencer801a3592010-07-26 02:17:32 +000061class COFFSymbol {
62public:
63 COFF::symbol Data;
Chris Lattnerb1622902010-07-11 22:07:02 +000064
Michael J. Spencer801a3592010-07-26 02:17:32 +000065 typedef llvm::SmallVector<AuxSymbol, 1> AuxiliarySymbols;
Chris Lattnerb1622902010-07-11 22:07:02 +000066
Michael J. Spencer801a3592010-07-26 02:17:32 +000067 name Name;
Michael J. Spencer9cf23a92010-09-27 21:17:39 +000068 int Index;
Michael J. Spencer801a3592010-07-26 02:17:32 +000069 AuxiliarySymbols Aux;
70 COFFSymbol *Other;
Michael J. Spencera72d8782010-09-27 08:58:26 +000071 COFFSection *Section;
72 int Relocations;
Michael J. Spencer801a3592010-07-26 02:17:32 +000073
74 MCSymbolData const *MCData;
75
Michael J. Spencera72d8782010-09-27 08:58:26 +000076 COFFSymbol(llvm::StringRef name);
Michael J. Spencer801a3592010-07-26 02:17:32 +000077 size_t size() const;
78 void set_name_offset(uint32_t Offset);
Michael J. Spencera72d8782010-09-27 08:58:26 +000079
80 bool should_keep() const;
Michael J. Spencer801a3592010-07-26 02:17:32 +000081};
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;
Michael J. Spencer9cf23a92010-09-27 21:17:39 +000099 int Number;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000100 MCSectionData const *MCData;
Michael J. Spencera72d8782010-09-27 08:58:26 +0000101 COFFSymbol *Symbol;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000102 relocations Relocations;
103
Michael J. Spencera72d8782010-09-27 08:58:26 +0000104 COFFSection(llvm::StringRef name);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000105 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
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000128 typedef DenseMap<MCSymbol const *, COFFSymbol *> symbol_map;
129 typedef DenseMap<MCSection const *, COFFSection *> section_map;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000130
131 // Root level file contents.
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000132 bool Is64Bit;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000133 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
Michael J. Spencerda0bfcd2010-08-21 05:58:13 +0000142 WinCOFFObjectWriter(raw_ostream &OS, bool is64Bit);
Benjamin Kramer808ecfc2010-07-29 11:57:59 +0000143 ~WinCOFFObjectWriter();
Michael J. Spencer801a3592010-07-26 02:17:32 +0000144
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000145 COFFSymbol *createSymbol(StringRef Name);
146 COFFSymbol *GetOrCreateCOFFSymbol(const MCSymbol * Symbol);
147 COFFSection *createSection(StringRef Name);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000148
Michael J. Spencer801a3592010-07-26 02:17:32 +0000149 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
Michael J. Spencera72d8782010-09-27 08:58:26 +0000155 void MakeSymbolReal(COFFSymbol &S, size_t Index);
156 void MakeSectionReal(COFFSection &S, size_t Number);
157
158 bool ExportSection(COFFSection const *S);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000159 bool ExportSymbol(MCSymbolData const &SymbolData, MCAssembler &Asm);
160
Michael J. Spencera72d8782010-09-27 08:58:26 +0000161 bool IsPhysicalSection(COFFSection *S);
162
Michael J. Spencer801a3592010-07-26 02:17:32 +0000163 // 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
Rafael Espindola85f2ecc2010-12-07 00:27:36 +0000173 void ExecutePostLayoutBinding(MCAssembler &Asm, const MCAsmLayout &Layout);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000174
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
Rafael Espindola8f413fa2010-10-05 15:11:03 +0000182 void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000183};
Chris Lattnerb1622902010-07-11 22:07:02 +0000184}
185
Michael J. Spencer801a3592010-07-26 02:17:32 +0000186static 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
Michael J. Spencera72d8782010-09-27 08:58:26 +0000208COFFSymbol::COFFSymbol(llvm::StringRef name)
209 : Name(name.begin(), name.end())
210 , Other(NULL)
211 , Section(NULL)
212 , Relocations(0)
213 , MCData(NULL) {
Michael J. Spencer801a3592010-07-26 02:17:32 +0000214 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
Michael J. Spencera72d8782010-09-27 08:58:26 +0000229/// 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
Michael J. Spencer801a3592010-07-26 02:17:32 +0000257//------------------------------------------------------------------------------
258// Section class implementation
259
Michael J. Spencera72d8782010-09-27 08:58:26 +0000260COFFSection::COFFSection(llvm::StringRef name)
261 : Name(name)
262 , MCData(NULL)
263 , Symbol(NULL) {
Michael J. Spencer801a3592010-07-26 02:17:32 +0000264 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
Michael J. Spencerda0bfcd2010-08-21 05:58:13 +0000316WinCOFFObjectWriter::WinCOFFObjectWriter(raw_ostream &OS, bool is64Bit)
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000317 : MCObjectWriter(OS, true)
318 , Is64Bit(is64Bit) {
Michael J. Spencer801a3592010-07-26 02:17:32 +0000319 memset(&Header, 0, sizeof(Header));
Michael J. Spencerda0bfcd2010-08-21 05:58:13 +0000320
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000321 Is64Bit ? Header.Machine = COFF::IMAGE_FILE_MACHINE_AMD64
Michael J. Spencerda0bfcd2010-08-21 05:58:13 +0000322 : Header.Machine = COFF::IMAGE_FILE_MACHINE_I386;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000323}
324
Benjamin Kramer808ecfc2010-07-29 11:57:59 +0000325WinCOFFObjectWriter::~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
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000332COFFSymbol *WinCOFFObjectWriter::createSymbol(StringRef Name) {
Michael J. Spencer801a3592010-07-26 02:17:32 +0000333 return createCOFFEntity<COFFSymbol>(Name, Symbols);
334}
335
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000336COFFSymbol *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
Michael J. Spencer801a3592010-07-26 02:17:32 +0000346COFFSection *WinCOFFObjectWriter::createSection(llvm::StringRef Name) {
347 return createCOFFEntity<COFFSection>(Name, Sections);
348}
349
Michael J. Spencer801a3592010-07-26 02:17:32 +0000350/// 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) {
Michael J. Spencera72d8782010-09-27 08:58:26 +0000355 object_t *Object = new object_t(Name);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000356
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) {
Michael J. Spencerd47f4a92010-10-09 11:00:37 +0000365 assert(SectionData.getSection().getVariant() == MCSection::SV_COFF
366 && "Got non COFF section in the COFF backend!");
Michael J. Spencer801a3592010-07-26 02:17:32 +0000367 // 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
Michael J. Spencera72d8782010-09-27 08:58:26 +0000374 coff_section->Symbol = coff_symbol;
375 coff_symbol->Section = coff_section;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000376 coff_symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000377
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;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000382 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;
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000408 SectionMap[&SectionData.getSection()] = coff_section;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000409}
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,
Michael J. Spencera72d8782010-09-27 08:58:26 +0000414 MCAssembler &Assembler) {
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000415 COFFSymbol *coff_symbol = GetOrCreateCOFFSymbol(&SymbolData.getSymbol());
Michael J. Spencer801a3592010-07-26 02:17:32 +0000416
417 coff_symbol->Data.Type = (SymbolData.getFlags() & 0x0000FFFF) >> 0;
418 coff_symbol->Data.StorageClass = (SymbolData.getFlags() & 0x00FF0000) >> 16;
419
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000420 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
Michael J. Spencer801a3592010-07-26 02:17:32 +0000455 // 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 =
Michael J. Spencer81100d02010-09-29 03:13:41 +0000460 external ? COFF::IMAGE_SYM_CLASS_EXTERNAL : COFF::IMAGE_SYM_CLASS_STATIC;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000461 }
462
Michael J. Spencera72d8782010-09-27 08:58:26 +0000463 if (SymbolData.Fragment != NULL)
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000464 coff_symbol->Section =
465 SectionMap[&SymbolData.Fragment->getParent()->getSection()];
Michael J. Spencera72d8782010-09-27 08:58:26 +0000466
Michael J. Spencer801a3592010-07-26 02:17:32 +0000467 // Bind internal COFF symbol to MC symbol.
468 coff_symbol->MCData = &SymbolData;
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000469 SymbolMap[&SymbolData.getSymbol()] = coff_symbol;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000470}
471
Michael J. Spencera72d8782010-09-27 08:58:26 +0000472/// 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 std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry));
488 } else
489 std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size());
490
491 S.Number = Number;
492 S.Symbol->Data.SectionNumber = S.Number;
493 S.Symbol->Aux[0].Aux.SectionDefinition.Number = S.Number;
494}
495
496void WinCOFFObjectWriter::MakeSymbolReal(COFFSymbol &S, size_t Index) {
497 if (S.Name.size() > COFF::NameSize) {
498 size_t StringTableEntry = Strings.insert(S.Name.c_str());
499
500 S.set_name_offset(StringTableEntry);
501 } else
502 std::memcpy(S.Data.Name, S.Name.c_str(), S.Name.size());
503 S.Index = Index;
504}
505
506bool WinCOFFObjectWriter::ExportSection(COFFSection const *S) {
507 return !S->MCData->getFragmentList().empty();
Michael J. Spencer801a3592010-07-26 02:17:32 +0000508}
509
510bool WinCOFFObjectWriter::ExportSymbol(MCSymbolData const &SymbolData,
511 MCAssembler &Asm) {
512 // This doesn't seem to be right. Strings referred to from the .data section
513 // need symbols so they can be linked to code in the .text section right?
514
515 // return Asm.isSymbolLinkerVisible (&SymbolData);
516
Michael J. Spencera72d8782010-09-27 08:58:26 +0000517 // For now, all non-variable symbols are exported,
518 // the linker will sort the rest out for us.
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000519 return SymbolData.isExternal() || !SymbolData.getSymbol().isVariable();
Michael J. Spencera72d8782010-09-27 08:58:26 +0000520}
521
522bool WinCOFFObjectWriter::IsPhysicalSection(COFFSection *S) {
523 return (S->Header.Characteristics
524 & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000525}
526
527//------------------------------------------------------------------------------
528// entity writing methods
529
530void WinCOFFObjectWriter::WriteFileHeader(const COFF::header &Header) {
531 WriteLE16(Header.Machine);
532 WriteLE16(Header.NumberOfSections);
533 WriteLE32(Header.TimeDateStamp);
534 WriteLE32(Header.PointerToSymbolTable);
535 WriteLE32(Header.NumberOfSymbols);
536 WriteLE16(Header.SizeOfOptionalHeader);
537 WriteLE16(Header.Characteristics);
538}
539
540void WinCOFFObjectWriter::WriteSymbol(const COFFSymbol *S) {
541 WriteBytes(StringRef(S->Data.Name, COFF::NameSize));
542 WriteLE32(S->Data.Value);
543 WriteLE16(S->Data.SectionNumber);
544 WriteLE16(S->Data.Type);
545 Write8(S->Data.StorageClass);
546 Write8(S->Data.NumberOfAuxSymbols);
547 WriteAuxiliarySymbols(S->Aux);
548}
549
550void WinCOFFObjectWriter::WriteAuxiliarySymbols(
551 const COFFSymbol::AuxiliarySymbols &S) {
552 for(COFFSymbol::AuxiliarySymbols::const_iterator i = S.begin(), e = S.end();
553 i != e; ++i) {
554 switch(i->AuxType) {
555 case ATFunctionDefinition:
556 WriteLE32(i->Aux.FunctionDefinition.TagIndex);
557 WriteLE32(i->Aux.FunctionDefinition.TotalSize);
558 WriteLE32(i->Aux.FunctionDefinition.PointerToLinenumber);
559 WriteLE32(i->Aux.FunctionDefinition.PointerToNextFunction);
560 WriteZeros(sizeof(i->Aux.FunctionDefinition.unused));
561 break;
562 case ATbfAndefSymbol:
563 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused1));
564 WriteLE16(i->Aux.bfAndefSymbol.Linenumber);
565 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused2));
566 WriteLE32(i->Aux.bfAndefSymbol.PointerToNextFunction);
567 WriteZeros(sizeof(i->Aux.bfAndefSymbol.unused3));
568 break;
569 case ATWeakExternal:
570 WriteLE32(i->Aux.WeakExternal.TagIndex);
571 WriteLE32(i->Aux.WeakExternal.Characteristics);
572 WriteZeros(sizeof(i->Aux.WeakExternal.unused));
573 break;
574 case ATFile:
575 WriteBytes(StringRef(reinterpret_cast<const char *>(i->Aux.File.FileName),
576 sizeof(i->Aux.File.FileName)));
577 break;
578 case ATSectionDefinition:
579 WriteLE32(i->Aux.SectionDefinition.Length);
580 WriteLE16(i->Aux.SectionDefinition.NumberOfRelocations);
581 WriteLE16(i->Aux.SectionDefinition.NumberOfLinenumbers);
582 WriteLE32(i->Aux.SectionDefinition.CheckSum);
583 WriteLE16(i->Aux.SectionDefinition.Number);
584 Write8(i->Aux.SectionDefinition.Selection);
585 WriteZeros(sizeof(i->Aux.SectionDefinition.unused));
586 break;
587 }
588 }
589}
590
591void WinCOFFObjectWriter::WriteSectionHeader(const COFF::section &S) {
592 WriteBytes(StringRef(S.Name, COFF::NameSize));
593
594 WriteLE32(S.VirtualSize);
595 WriteLE32(S.VirtualAddress);
596 WriteLE32(S.SizeOfRawData);
597 WriteLE32(S.PointerToRawData);
598 WriteLE32(S.PointerToRelocations);
599 WriteLE32(S.PointerToLineNumbers);
600 WriteLE16(S.NumberOfRelocations);
601 WriteLE16(S.NumberOfLineNumbers);
602 WriteLE32(S.Characteristics);
603}
604
605void WinCOFFObjectWriter::WriteRelocation(const COFF::relocation &R) {
606 WriteLE32(R.VirtualAddress);
607 WriteLE32(R.SymbolTableIndex);
608 WriteLE16(R.Type);
Chris Lattnerb1622902010-07-11 22:07:02 +0000609}
610
611////////////////////////////////////////////////////////////////////////////////
612// MCObjectWriter interface implementations
613
Rafael Espindola85f2ecc2010-12-07 00:27:36 +0000614void WinCOFFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
615 const MCAsmLayout &Layout) {
Michael J. Spencer801a3592010-07-26 02:17:32 +0000616 // "Define" each section & symbol. This creates section & symbol
Michael J. Spencera72d8782010-09-27 08:58:26 +0000617 // entries in the staging area.
Michael J. Spencer801a3592010-07-26 02:17:32 +0000618
619 for (MCAssembler::const_iterator i = Asm.begin(), e = Asm.end(); i != e; i++)
620 DefineSection(*i);
621
622 for (MCAssembler::const_symbol_iterator i = Asm.symbol_begin(),
623 e = Asm.symbol_end(); i != e; i++) {
624 if (ExportSymbol(*i, Asm))
625 DefineSymbol(*i, Asm);
626 }
Chris Lattnerb1622902010-07-11 22:07:02 +0000627}
628
629void WinCOFFObjectWriter::RecordRelocation(const MCAssembler &Asm,
630 const MCAsmLayout &Layout,
631 const MCFragment *Fragment,
632 const MCFixup &Fixup,
633 MCValue Target,
634 uint64_t &FixedValue) {
Michael J. Spencer801a3592010-07-26 02:17:32 +0000635 assert(Target.getSymA() != NULL && "Relocation must reference a symbol!");
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000636
637 const MCSymbol *A = &Target.getSymA()->getSymbol();
638 MCSymbolData &A_SD = Asm.getSymbolData(*A);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000639
640 MCSectionData const *SectionData = Fragment->getParent();
Michael J. Spencer801a3592010-07-26 02:17:32 +0000641
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000642 // Mark this symbol as requiring an entry in the symbol table.
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000643 assert(SectionMap.find(&SectionData->getSection()) != SectionMap.end() &&
Michael J. Spencer801a3592010-07-26 02:17:32 +0000644 "Section must already have been defined in ExecutePostLayoutBinding!");
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000645 assert(SymbolMap.find(&A_SD.getSymbol()) != SymbolMap.end() &&
Michael J. Spencer801a3592010-07-26 02:17:32 +0000646 "Symbol must already have been defined in ExecutePostLayoutBinding!");
647
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000648 COFFSection *coff_section = SectionMap[&SectionData->getSection()];
649 COFFSymbol *coff_symbol = SymbolMap[&A_SD.getSymbol()];
Rafael Espindola3660a842011-04-20 14:01:45 +0000650 const MCSymbolRefExpr *SymA = Target.getSymA();
651 const MCSymbolRefExpr *SymB = Target.getSymB();
652 const bool CrossSection = SymB &&
653 &SymA->getSymbol().getSection() != &SymB->getSymbol().getSection();
Michael J. Spencer801a3592010-07-26 02:17:32 +0000654
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000655 if (Target.getSymB()) {
656 const MCSymbol *B = &Target.getSymB()->getSymbol();
657 MCSymbolData &B_SD = Asm.getSymbolData(*B);
658
Rafael Espindola1ac7fe02011-04-21 18:36:50 +0000659 // Offset of the symbol in the section
660 int64_t a = Layout.getSymbolOffset(&B_SD);
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000661
Rafael Espindola1ac7fe02011-04-21 18:36:50 +0000662 // Ofeset of the relocation in the section
663 int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
664
665 FixedValue = b - a;
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000666 // In the case where we have SymbA and SymB, we just need to store the delta
667 // between the two symbols. Update FixedValue to account for the delta, and
668 // skip recording the relocation.
Rafael Espindola3660a842011-04-20 14:01:45 +0000669 if (!CrossSection)
670 return;
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000671 } else {
672 FixedValue = Target.getConstant();
673 }
Michael J. Spencer801a3592010-07-26 02:17:32 +0000674
675 COFFRelocation Reloc;
676
Daniel Dunbar425f6342010-07-31 21:08:54 +0000677 Reloc.Data.SymbolTableIndex = 0;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000678 Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment);
Michael J. Spencera72d8782010-09-27 08:58:26 +0000679
Michael J. Spencerea1104a2010-10-05 19:48:12 +0000680 // Turn relocations for temporary symbols into section relocations.
Rafael Espindola3660a842011-04-20 14:01:45 +0000681 if (coff_symbol->MCData->getSymbol().isTemporary() || CrossSection) {
Michael J. Spencera72d8782010-09-27 08:58:26 +0000682 Reloc.Symb = coff_symbol->Section->Symbol;
Michael J. Spencereb6e77f2010-10-05 19:48:03 +0000683 FixedValue += Layout.getFragmentOffset(coff_symbol->MCData->Fragment)
684 + coff_symbol->MCData->getOffset();
Michael J. Spencera72d8782010-09-27 08:58:26 +0000685 } else
686 Reloc.Symb = coff_symbol;
687
688 ++Reloc.Symb->Relocations;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000689
690 Reloc.Data.VirtualAddress += Fixup.getOffset();
691
Rafael Espindola3660a842011-04-20 14:01:45 +0000692 unsigned FixupKind = Fixup.getKind();
693
694 if (CrossSection)
695 FixupKind = FK_PCRel_4;
696
697 switch (FixupKind) {
Rafael Espindolae04ed7e2010-11-28 14:17:56 +0000698 case FK_PCRel_4:
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000699 case X86::reloc_riprel_4byte:
700 case X86::reloc_riprel_4byte_movq_load:
701 Reloc.Data.Type = Is64Bit ? COFF::IMAGE_REL_AMD64_REL32
702 : COFF::IMAGE_REL_I386_REL32;
703 // FIXME: Can anyone explain what this does other than adjust for the size
704 // of the offset?
705 FixedValue += 4;
706 break;
707 case FK_Data_4:
Rafael Espindolaa8c02c32010-09-30 03:11:42 +0000708 case X86::reloc_signed_4byte:
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000709 Reloc.Data.Type = Is64Bit ? COFF::IMAGE_REL_AMD64_ADDR32
710 : COFF::IMAGE_REL_I386_DIR32;
711 break;
712 case FK_Data_8:
713 if (Is64Bit)
714 Reloc.Data.Type = COFF::IMAGE_REL_AMD64_ADDR64;
715 else
Michael J. Spencerda0bfcd2010-08-21 05:58:13 +0000716 llvm_unreachable("unsupported relocation type");
Michael J. Spencer82c84fd2010-08-24 21:04:52 +0000717 break;
718 default:
719 llvm_unreachable("unsupported relocation type");
720 }
Michael J. Spencer801a3592010-07-26 02:17:32 +0000721
722 coff_section->Relocations.push_back(Reloc);
Chris Lattnerb1622902010-07-11 22:07:02 +0000723}
724
Rafael Espindola8f413fa2010-10-05 15:11:03 +0000725void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
Chris Lattnerb1622902010-07-11 22:07:02 +0000726 const MCAsmLayout &Layout) {
Michael J. Spencer801a3592010-07-26 02:17:32 +0000727 // Assign symbol and section indexes and offsets.
Michael J. Spencera72d8782010-09-27 08:58:26 +0000728 Header.NumberOfSections = 0;
729
730 for (sections::iterator i = Sections.begin(),
731 e = Sections.end(); i != e; i++) {
Rafael Espindola85f2ecc2010-12-07 00:27:36 +0000732 if (Layout.getSectionAddressSize((*i)->MCData) > 0) {
Michael J. Spencera72d8782010-09-27 08:58:26 +0000733 MakeSectionReal(**i, ++Header.NumberOfSections);
734 } else {
735 (*i)->Number = -1;
736 }
737 }
Michael J. Spencer801a3592010-07-26 02:17:32 +0000738
739 Header.NumberOfSymbols = 0;
740
741 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
742 COFFSymbol *coff_symbol = *i;
743 MCSymbolData const *SymbolData = coff_symbol->MCData;
744
Michael J. Spencer801a3592010-07-26 02:17:32 +0000745 // Update section number & offset for symbols that have them.
746 if ((SymbolData != NULL) && (SymbolData->Fragment != NULL)) {
Michael J. Spencera72d8782010-09-27 08:58:26 +0000747 assert(coff_symbol->Section != NULL);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000748
Michael J. Spencera72d8782010-09-27 08:58:26 +0000749 coff_symbol->Data.SectionNumber = coff_symbol->Section->Number;
Michael J. Spencer237f8fe2010-08-03 05:02:46 +0000750 coff_symbol->Data.Value = Layout.getFragmentOffset(SymbolData->Fragment)
751 + SymbolData->Offset;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000752 }
753
Michael J. Spencera72d8782010-09-27 08:58:26 +0000754 if (coff_symbol->should_keep()) {
755 MakeSymbolReal(*coff_symbol, Header.NumberOfSymbols++);
756
757 // Update auxiliary symbol info.
758 coff_symbol->Data.NumberOfAuxSymbols = coff_symbol->Aux.size();
759 Header.NumberOfSymbols += coff_symbol->Data.NumberOfAuxSymbols;
760 } else
761 coff_symbol->Index = -1;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000762 }
763
764 // Fixup weak external references.
765 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++) {
Michael J. Spencera72d8782010-09-27 08:58:26 +0000766 COFFSymbol *coff_symbol = *i;
767 if (coff_symbol->Other != NULL) {
768 assert(coff_symbol->Index != -1);
769 assert(coff_symbol->Aux.size() == 1 &&
Michael J. Spencer801a3592010-07-26 02:17:32 +0000770 "Symbol must contain one aux symbol!");
Michael J. Spencera72d8782010-09-27 08:58:26 +0000771 assert(coff_symbol->Aux[0].AuxType == ATWeakExternal &&
Michael J. Spencer801a3592010-07-26 02:17:32 +0000772 "Symbol's aux symbol must be a Weak External!");
Michael J. Spencera72d8782010-09-27 08:58:26 +0000773 coff_symbol->Aux[0].Aux.WeakExternal.TagIndex = coff_symbol->Other->Index;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000774 }
775 }
776
777 // Assign file offsets to COFF object file structures.
778
779 unsigned offset = 0;
780
781 offset += COFF::HeaderSize;
Michael J. Spencera72d8782010-09-27 08:58:26 +0000782 offset += COFF::SectionSize * Header.NumberOfSections;
Michael J. Spencer801a3592010-07-26 02:17:32 +0000783
784 for (MCAssembler::const_iterator i = Asm.begin(),
785 e = Asm.end();
786 i != e; i++) {
Michael J. Spencer4cee2892010-10-16 08:25:57 +0000787 COFFSection *Sec = SectionMap[&i->getSection()];
Michael J. Spencer801a3592010-07-26 02:17:32 +0000788
Michael J. Spencera72d8782010-09-27 08:58:26 +0000789 if (Sec->Number == -1)
790 continue;
791
Michael J. Spencer28ca86a2010-10-09 16:04:45 +0000792 Sec->Header.SizeOfRawData = Layout.getSectionAddressSize(i);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000793
Michael J. Spencera72d8782010-09-27 08:58:26 +0000794 if (IsPhysicalSection(Sec)) {
Michael J. Spencer801a3592010-07-26 02:17:32 +0000795 Sec->Header.PointerToRawData = offset;
796
797 offset += Sec->Header.SizeOfRawData;
798 }
799
800 if (Sec->Relocations.size() > 0) {
801 Sec->Header.NumberOfRelocations = Sec->Relocations.size();
802 Sec->Header.PointerToRelocations = offset;
803
804 offset += COFF::RelocationSize * Sec->Relocations.size();
805
806 for (relocations::iterator cr = Sec->Relocations.begin(),
807 er = Sec->Relocations.end();
Michael J. Spencera72d8782010-09-27 08:58:26 +0000808 cr != er; ++cr) {
809 assert((*cr).Symb->Index != -1);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000810 (*cr).Data.SymbolTableIndex = (*cr).Symb->Index;
811 }
812 }
813
Michael J. Spencera72d8782010-09-27 08:58:26 +0000814 assert(Sec->Symbol->Aux.size() == 1
815 && "Section's symbol must have one aux!");
816 AuxSymbol &Aux = Sec->Symbol->Aux[0];
Michael J. Spencer801a3592010-07-26 02:17:32 +0000817 assert(Aux.AuxType == ATSectionDefinition &&
818 "Section's symbol's aux symbol must be a Section Definition!");
819 Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData;
820 Aux.Aux.SectionDefinition.NumberOfRelocations =
821 Sec->Header.NumberOfRelocations;
822 Aux.Aux.SectionDefinition.NumberOfLinenumbers =
823 Sec->Header.NumberOfLineNumbers;
824 }
825
826 Header.PointerToSymbolTable = offset;
827
Michael J. Spencerab3de492010-08-03 04:43:33 +0000828 Header.TimeDateStamp = sys::TimeValue::now().toEpochTime();
829
Michael J. Spencer801a3592010-07-26 02:17:32 +0000830 // Write it all to disk...
831 WriteFileHeader(Header);
832
833 {
834 sections::iterator i, ie;
835 MCAssembler::const_iterator j, je;
836
837 for (i = Sections.begin(), ie = Sections.end(); i != ie; i++)
Michael J. Spencera72d8782010-09-27 08:58:26 +0000838 if ((*i)->Number != -1)
839 WriteSectionHeader((*i)->Header);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000840
841 for (i = Sections.begin(), ie = Sections.end(),
842 j = Asm.begin(), je = Asm.end();
Michael J. Spencera72d8782010-09-27 08:58:26 +0000843 (i != ie) && (j != je); ++i, ++j) {
844
845 if ((*i)->Number == -1)
846 continue;
847
Michael J. Spencer801a3592010-07-26 02:17:32 +0000848 if ((*i)->Header.PointerToRawData != 0) {
849 assert(OS.tell() == (*i)->Header.PointerToRawData &&
850 "Section::PointerToRawData is insane!");
851
Daniel Dunbar5d2477c2010-12-17 02:45:59 +0000852 Asm.WriteSectionData(j, Layout);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000853 }
854
855 if ((*i)->Relocations.size() > 0) {
856 assert(OS.tell() == (*i)->Header.PointerToRelocations &&
857 "Section::PointerToRelocations is insane!");
858
859 for (relocations::const_iterator k = (*i)->Relocations.begin(),
860 ke = (*i)->Relocations.end();
861 k != ke; k++) {
862 WriteRelocation(k->Data);
863 }
864 } else
865 assert((*i)->Header.PointerToRelocations == 0 &&
866 "Section::PointerToRelocations is insane!");
867 }
868 }
869
870 assert(OS.tell() == Header.PointerToSymbolTable &&
871 "Header::PointerToSymbolTable is insane!");
872
873 for (symbols::iterator i = Symbols.begin(), e = Symbols.end(); i != e; i++)
Michael J. Spencera72d8782010-09-27 08:58:26 +0000874 if ((*i)->Index != -1)
875 WriteSymbol(*i);
Michael J. Spencer801a3592010-07-26 02:17:32 +0000876
877 OS.write((char const *)&Strings.Data.front(), Strings.Data.size());
Chris Lattnerb1622902010-07-11 22:07:02 +0000878}
879
880//------------------------------------------------------------------------------
881// WinCOFFObjectWriter factory function
882
883namespace llvm {
Michael J. Spencerda0bfcd2010-08-21 05:58:13 +0000884 MCObjectWriter *createWinCOFFObjectWriter(raw_ostream &OS, bool is64Bit) {
885 return new WinCOFFObjectWriter(OS, is64Bit);
Chris Lattnerb1622902010-07-11 22:07:02 +0000886 }
Michael J. Spencer933304e2010-07-26 03:01:28 +0000887}