ObjectFile.h revision 255f89faee13dc491cb64fbeae3c763e7e2ea4e6 
1//===- ObjectFile.h - File format independent object file -------*- 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 declares a file format independent ObjectFile class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_OBJECT_OBJECT_FILE_H
15#define LLVM_OBJECT_OBJECT_FILE_H
16
17#include "llvm/ADT/StringRef.h"
18#include "llvm/Object/Binary.h"
19#include "llvm/Support/DataTypes.h"
20#include "llvm/Support/ErrorHandling.h"
21#include "llvm/Support/MemoryBuffer.h"
22#include <cstring>
23#include <vector>
24
25namespace llvm {
26namespace object {
27
28class ObjectFile;
29
30union DataRefImpl {
31  struct {
32    // ELF needs this for relocations. This entire union should probably be a
33    // char[max(8, sizeof(uintptr_t))] and require the impl to cast.
34    uint16_t a, b;
35    uint32_t c;
36  } w;
37  struct {
38    uint32_t a, b;
39  } d;
40  uintptr_t p;
41  DataRefImpl() {
42    std::memset(this, 0, sizeof(DataRefImpl));
43  }
44};
45
46template<class content_type>
47class content_iterator {
48  content_type Current;
49public:
50  content_iterator(content_type symb)
51    : Current(symb) {}
52
53  const content_type* operator->() const {
54    return &Current;
55  }
56
57  const content_type &operator*() const {
58    return Current;
59  }
60
61  bool operator==(const content_iterator &other) const {
62    return Current == other.Current;
63  }
64
65  bool operator!=(const content_iterator &other) const {
66    return !(*this == other);
67  }
68
69  content_iterator& increment(error_code &err) {
70    content_type next;
71    if (error_code ec = Current.getNext(next))
72      err = ec;
73    else
74      Current = next;
75    return *this;
76  }
77};
78
79inline bool operator==(const DataRefImpl &a, const DataRefImpl &b) {
80  // Check bitwise identical. This is the only legal way to compare a union w/o
81  // knowing which member is in use.
82  return std::memcmp(&a, &b, sizeof(DataRefImpl)) == 0;
83}
84
85inline bool operator<(const DataRefImpl &a, const DataRefImpl &b) {
86  // Check bitwise identical. This is the only legal way to compare a union w/o
87  // knowing which member is in use.
88  return std::memcmp(&a, &b, sizeof(DataRefImpl)) < 0;
89}
90
91class SymbolRef;
92
93/// RelocationRef - This is a value type class that represents a single
94/// relocation in the list of relocations in the object file.
95class RelocationRef {
96  DataRefImpl RelocationPimpl;
97  const ObjectFile *OwningObject;
98
99public:
100  RelocationRef() : OwningObject(NULL) { }
101
102  RelocationRef(DataRefImpl RelocationP, const ObjectFile *Owner);
103
104  bool operator==(const RelocationRef &Other) const;
105
106  error_code getNext(RelocationRef &Result) const;
107
108  error_code getAddress(uint64_t &Result) const;
109  error_code getOffset(uint64_t &Result) const;
110  error_code getSymbol(SymbolRef &Result) const;
111  error_code getType(uint64_t &Result) const;
112
113  /// @brief Indicates whether this relocation should hidden when listing
114  /// relocations, usually because it is the trailing part of a multipart
115  /// relocation that will be printed as part of the leading relocation.
116  error_code getHidden(bool &Result) const;
117
118  /// @brief Get a string that represents the type of this relocation.
119  ///
120  /// This is for display purposes only.
121  error_code getTypeName(SmallVectorImpl<char> &Result) const;
122  error_code getAdditionalInfo(int64_t &Result) const;
123
124  /// @brief Get a string that represents the calculation of the value of this
125  ///        relocation.
126  ///
127  /// This is for display purposes only.
128  error_code getValueString(SmallVectorImpl<char> &Result) const;
129
130  DataRefImpl getRawDataRefImpl() const;
131};
132typedef content_iterator<RelocationRef> relocation_iterator;
133
134/// SectionRef - This is a value type class that represents a single section in
135/// the list of sections in the object file.
136class SectionRef {
137  friend class SymbolRef;
138  DataRefImpl SectionPimpl;
139  const ObjectFile *OwningObject;
140
141public:
142  SectionRef() : OwningObject(NULL) { }
143
144  SectionRef(DataRefImpl SectionP, const ObjectFile *Owner);
145
146  bool operator==(const SectionRef &Other) const;
147  bool operator<(const SectionRef &Other) const;
148
149  error_code getNext(SectionRef &Result) const;
150
151  error_code getName(StringRef &Result) const;
152  error_code getAddress(uint64_t &Result) const;
153  error_code getSize(uint64_t &Result) const;
154  error_code getContents(StringRef &Result) const;
155
156  /// @brief Get the alignment of this section as the actual value (not log 2).
157  error_code getAlignment(uint64_t &Result) const;
158
159  // FIXME: Move to the normalization layer when it's created.
160  error_code isText(bool &Result) const;
161  error_code isData(bool &Result) const;
162  error_code isBSS(bool &Result) const;
163  error_code isRequiredForExecution(bool &Result) const;
164  error_code isVirtual(bool &Result) const;
165  error_code isZeroInit(bool &Result) const;
166  error_code isReadOnlyData(bool &Result) const;
167
168  error_code containsSymbol(SymbolRef S, bool &Result) const;
169
170  relocation_iterator begin_relocations() const;
171  relocation_iterator end_relocations() const;
172
173  DataRefImpl getRawDataRefImpl() const;
174};
175typedef content_iterator<SectionRef> section_iterator;
176
177/// SymbolRef - This is a value type class that represents a single symbol in
178/// the list of symbols in the object file.
179class SymbolRef {
180  friend class SectionRef;
181  DataRefImpl SymbolPimpl;
182  const ObjectFile *OwningObject;
183
184public:
185  SymbolRef() : OwningObject(NULL) { }
186
187  enum Type {
188    ST_Unknown, // Type not specified
189    ST_Data,
190    ST_Debug,
191    ST_File,
192    ST_Function,
193    ST_Other
194  };
195
196  enum Flags {
197    SF_None            = 0,
198    SF_Undefined       = 1U << 0,  // Symbol is defined in another object file
199    SF_Global          = 1U << 1,  // Global symbol
200    SF_Weak            = 1U << 2,  // Weak symbol
201    SF_Absolute        = 1U << 3,  // Absolute symbol
202    SF_ThreadLocal     = 1U << 4,  // Thread local symbol
203    SF_Common          = 1U << 5,  // Symbol has common linkage
204    SF_FormatSpecific  = 1U << 31  // Specific to the object file format
205                                   // (e.g. section symbols)
206  };
207
208  SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner);
209
210  bool operator==(const SymbolRef &Other) const;
211  bool operator<(const SymbolRef &Other) const;
212
213  error_code getNext(SymbolRef &Result) const;
214
215  error_code getName(StringRef &Result) const;
216  /// Returns the symbol virtual address (i.e. address at which it will be
217  /// mapped).
218  error_code getAddress(uint64_t &Result) const;
219  error_code getFileOffset(uint64_t &Result) const;
220  error_code getSize(uint64_t &Result) const;
221  error_code getType(SymbolRef::Type &Result) const;
222
223  /// Returns the ascii char that should be displayed in a symbol table dump via
224  /// nm for this symbol.
225  error_code getNMTypeChar(char &Result) const;
226
227  /// Get symbol flags (bitwise OR of SymbolRef::Flags)
228  error_code getFlags(uint32_t &Result) const;
229
230  /// @brief Return true for common symbols such as uninitialized globals
231  error_code isCommon(bool &Result) const;
232
233  /// @brief Get section this symbol is defined in reference to. Result is
234  /// end_sections() if it is undefined or is an absolute symbol.
235  error_code getSection(section_iterator &Result) const;
236
237  /// @brief Get value of the symbol in the symbol table.
238  error_code getValue(uint64_t &Val) const;
239
240  DataRefImpl getRawDataRefImpl() const;
241};
242typedef content_iterator<SymbolRef> symbol_iterator;
243
244/// LibraryRef - This is a value type class that represents a single library in
245/// the list of libraries needed by a shared or dynamic object.
246class LibraryRef {
247  friend class SectionRef;
248  DataRefImpl LibraryPimpl;
249  const ObjectFile *OwningObject;
250
251public:
252  LibraryRef() : OwningObject(NULL) { }
253
254  LibraryRef(DataRefImpl LibraryP, const ObjectFile *Owner);
255
256  bool operator==(const LibraryRef &Other) const;
257  bool operator<(const LibraryRef &Other) const;
258
259  error_code getNext(LibraryRef &Result) const;
260
261  // Get the path to this library, as stored in the object file.
262  error_code getPath(StringRef &Result) const;
263
264  DataRefImpl getRawDataRefImpl() const;
265};
266typedef content_iterator<LibraryRef> library_iterator;
267
268const uint64_t UnknownAddressOrSize = ~0ULL;
269
270/// ObjectFile - This class is the base class for all object file types.
271/// Concrete instances of this object are created by createObjectFile, which
272/// figures out which type to create.
273class ObjectFile : public Binary {
274  virtual void anchor();
275  ObjectFile() LLVM_DELETED_FUNCTION;
276  ObjectFile(const ObjectFile &other) LLVM_DELETED_FUNCTION;
277
278protected:
279  ObjectFile(unsigned int Type, MemoryBuffer *source, error_code &ec);
280
281  const uint8_t *base() const {
282    return reinterpret_cast<const uint8_t *>(Data->getBufferStart());
283  }
284
285  // These functions are for SymbolRef to call internally. The main goal of
286  // this is to allow SymbolRef::SymbolPimpl to point directly to the symbol
287  // entry in the memory mapped object file. SymbolPimpl cannot contain any
288  // virtual functions because then it could not point into the memory mapped
289  // file.
290  //
291  // Implementations assume that the DataRefImpl is valid and has not been
292  // modified externally. It's UB otherwise.
293  friend class SymbolRef;
294  virtual error_code getSymbolNext(DataRefImpl Symb, SymbolRef &Res) const = 0;
295  virtual error_code getSymbolName(DataRefImpl Symb, StringRef &Res) const = 0;
296  virtual error_code getSymbolAddress(DataRefImpl Symb, uint64_t &Res) const = 0;
297  virtual error_code getSymbolFileOffset(DataRefImpl Symb, uint64_t &Res)const=0;
298  virtual error_code getSymbolSize(DataRefImpl Symb, uint64_t &Res) const = 0;
299  virtual error_code getSymbolType(DataRefImpl Symb,
300                                   SymbolRef::Type &Res) const = 0;
301  virtual error_code getSymbolNMTypeChar(DataRefImpl Symb, char &Res) const = 0;
302  virtual error_code getSymbolFlags(DataRefImpl Symb,
303                                    uint32_t &Res) const = 0;
304  virtual error_code getSymbolSection(DataRefImpl Symb,
305                                      section_iterator &Res) const = 0;
306  virtual error_code getSymbolValue(DataRefImpl Symb, uint64_t &Val) const = 0;
307
308  // Same as above for SectionRef.
309  friend class SectionRef;
310  virtual error_code getSectionNext(DataRefImpl Sec, SectionRef &Res) const = 0;
311  virtual error_code getSectionName(DataRefImpl Sec, StringRef &Res) const = 0;
312  virtual error_code getSectionAddress(DataRefImpl Sec, uint64_t &Res) const =0;
313  virtual error_code getSectionSize(DataRefImpl Sec, uint64_t &Res) const = 0;
314  virtual error_code getSectionContents(DataRefImpl Sec, StringRef &Res)const=0;
315  virtual error_code getSectionAlignment(DataRefImpl Sec, uint64_t &Res)const=0;
316  virtual error_code isSectionText(DataRefImpl Sec, bool &Res) const = 0;
317  virtual error_code isSectionData(DataRefImpl Sec, bool &Res) const = 0;
318  virtual error_code isSectionBSS(DataRefImpl Sec, bool &Res) const = 0;
319  virtual error_code isSectionRequiredForExecution(DataRefImpl Sec,
320                                                   bool &Res) const = 0;
321  // A section is 'virtual' if its contents aren't present in the object image.
322  virtual error_code isSectionVirtual(DataRefImpl Sec, bool &Res) const = 0;
323  virtual error_code isSectionZeroInit(DataRefImpl Sec, bool &Res) const = 0;
324  virtual error_code isSectionReadOnlyData(DataRefImpl Sec, bool &Res) const =0;
325  virtual error_code sectionContainsSymbol(DataRefImpl Sec, DataRefImpl Symb,
326                                           bool &Result) const = 0;
327  virtual relocation_iterator getSectionRelBegin(DataRefImpl Sec) const = 0;
328  virtual relocation_iterator getSectionRelEnd(DataRefImpl Sec) const = 0;
329
330
331  // Same as above for RelocationRef.
332  friend class RelocationRef;
333  virtual error_code getRelocationNext(DataRefImpl Rel,
334                                       RelocationRef &Res) const = 0;
335  virtual error_code getRelocationAddress(DataRefImpl Rel,
336                                          uint64_t &Res) const =0;
337  virtual error_code getRelocationOffset(DataRefImpl Rel,
338                                         uint64_t &Res) const =0;
339  virtual error_code getRelocationSymbol(DataRefImpl Rel,
340                                         SymbolRef &Res) const = 0;
341  virtual error_code getRelocationType(DataRefImpl Rel,
342                                       uint64_t &Res) const = 0;
343  virtual error_code getRelocationTypeName(DataRefImpl Rel,
344                                       SmallVectorImpl<char> &Result) const = 0;
345  virtual error_code getRelocationAdditionalInfo(DataRefImpl Rel,
346                                                 int64_t &Res) const = 0;
347  virtual error_code getRelocationValueString(DataRefImpl Rel,
348                                       SmallVectorImpl<char> &Result) const = 0;
349  virtual error_code getRelocationHidden(DataRefImpl Rel, bool &Result) const {
350    Result = false;
351    return object_error::success;
352  }
353
354  // Same for LibraryRef
355  friend class LibraryRef;
356  virtual error_code getLibraryNext(DataRefImpl Lib, LibraryRef &Res) const = 0;
357  virtual error_code getLibraryPath(DataRefImpl Lib, StringRef &Res) const = 0;
358
359public:
360
361  virtual symbol_iterator begin_symbols() const = 0;
362  virtual symbol_iterator end_symbols() const = 0;
363
364  virtual symbol_iterator begin_dynamic_symbols() const = 0;
365  virtual symbol_iterator end_dynamic_symbols() const = 0;
366
367  virtual section_iterator begin_sections() const = 0;
368  virtual section_iterator end_sections() const = 0;
369
370  virtual library_iterator begin_libraries_needed() const = 0;
371  virtual library_iterator end_libraries_needed() const = 0;
372
373  /// @brief The number of bytes used to represent an address in this object
374  ///        file format.
375  virtual uint8_t getBytesInAddress() const = 0;
376
377  virtual StringRef getFileFormatName() const = 0;
378  virtual /* Triple::ArchType */ unsigned getArch() const = 0;
379
380  /// For shared objects, returns the name which this object should be
381  /// loaded from at runtime. This corresponds to DT_SONAME on ELF and
382  /// LC_ID_DYLIB (install name) on MachO.
383  virtual StringRef getLoadName() const = 0;
384
385  /// @returns Pointer to ObjectFile subclass to handle this type of object.
386  /// @param ObjectPath The path to the object file. ObjectPath.isObject must
387  ///        return true.
388  /// @brief Create ObjectFile from path.
389  static ObjectFile *createObjectFile(StringRef ObjectPath);
390  static ObjectFile *createObjectFile(MemoryBuffer *Object);
391
392  static inline bool classof(const Binary *v) {
393    return v->isObject();
394  }
395
396public:
397  static ObjectFile *createCOFFObjectFile(MemoryBuffer *Object);
398  static ObjectFile *createELFObjectFile(MemoryBuffer *Object);
399  static ObjectFile *createMachOObjectFile(MemoryBuffer *Object);
400};
401
402// Inline function definitions.
403inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner)
404  : SymbolPimpl(SymbolP)
405  , OwningObject(Owner) {}
406
407inline bool SymbolRef::operator==(const SymbolRef &Other) const {
408  return SymbolPimpl == Other.SymbolPimpl;
409}
410
411inline bool SymbolRef::operator<(const SymbolRef &Other) const {
412  return SymbolPimpl < Other.SymbolPimpl;
413}
414
415inline error_code SymbolRef::getNext(SymbolRef &Result) const {
416  return OwningObject->getSymbolNext(SymbolPimpl, Result);
417}
418
419inline error_code SymbolRef::getName(StringRef &Result) const {
420  return OwningObject->getSymbolName(SymbolPimpl, Result);
421}
422
423inline error_code SymbolRef::getAddress(uint64_t &Result) const {
424  return OwningObject->getSymbolAddress(SymbolPimpl, Result);
425}
426
427inline error_code SymbolRef::getFileOffset(uint64_t &Result) const {
428  return OwningObject->getSymbolFileOffset(SymbolPimpl, Result);
429}
430
431inline error_code SymbolRef::getSize(uint64_t &Result) const {
432  return OwningObject->getSymbolSize(SymbolPimpl, Result);
433}
434
435inline error_code SymbolRef::getNMTypeChar(char &Result) const {
436  return OwningObject->getSymbolNMTypeChar(SymbolPimpl, Result);
437}
438
439inline error_code SymbolRef::getFlags(uint32_t &Result) const {
440  return OwningObject->getSymbolFlags(SymbolPimpl, Result);
441}
442
443inline error_code SymbolRef::getSection(section_iterator &Result) const {
444  return OwningObject->getSymbolSection(SymbolPimpl, Result);
445}
446
447inline error_code SymbolRef::getType(SymbolRef::Type &Result) const {
448  return OwningObject->getSymbolType(SymbolPimpl, Result);
449}
450
451inline error_code SymbolRef::getValue(uint64_t &Val) const {
452  return OwningObject->getSymbolValue(SymbolPimpl, Val);
453}
454
455inline DataRefImpl SymbolRef::getRawDataRefImpl() const {
456  return SymbolPimpl;
457}
458
459
460/// SectionRef
461inline SectionRef::SectionRef(DataRefImpl SectionP,
462                              const ObjectFile *Owner)
463  : SectionPimpl(SectionP)
464  , OwningObject(Owner) {}
465
466inline bool SectionRef::operator==(const SectionRef &Other) const {
467  return SectionPimpl == Other.SectionPimpl;
468}
469
470inline bool SectionRef::operator<(const SectionRef &Other) const {
471  return SectionPimpl < Other.SectionPimpl;
472}
473
474inline error_code SectionRef::getNext(SectionRef &Result) const {
475  return OwningObject->getSectionNext(SectionPimpl, Result);
476}
477
478inline error_code SectionRef::getName(StringRef &Result) const {
479  return OwningObject->getSectionName(SectionPimpl, Result);
480}
481
482inline error_code SectionRef::getAddress(uint64_t &Result) const {
483  return OwningObject->getSectionAddress(SectionPimpl, Result);
484}
485
486inline error_code SectionRef::getSize(uint64_t &Result) const {
487  return OwningObject->getSectionSize(SectionPimpl, Result);
488}
489
490inline error_code SectionRef::getContents(StringRef &Result) const {
491  return OwningObject->getSectionContents(SectionPimpl, Result);
492}
493
494inline error_code SectionRef::getAlignment(uint64_t &Result) const {
495  return OwningObject->getSectionAlignment(SectionPimpl, Result);
496}
497
498inline error_code SectionRef::isText(bool &Result) const {
499  return OwningObject->isSectionText(SectionPimpl, Result);
500}
501
502inline error_code SectionRef::isData(bool &Result) const {
503  return OwningObject->isSectionData(SectionPimpl, Result);
504}
505
506inline error_code SectionRef::isBSS(bool &Result) const {
507  return OwningObject->isSectionBSS(SectionPimpl, Result);
508}
509
510inline error_code SectionRef::isRequiredForExecution(bool &Result) const {
511  return OwningObject->isSectionRequiredForExecution(SectionPimpl, Result);
512}
513
514inline error_code SectionRef::isVirtual(bool &Result) const {
515  return OwningObject->isSectionVirtual(SectionPimpl, Result);
516}
517
518inline error_code SectionRef::isZeroInit(bool &Result) const {
519  return OwningObject->isSectionZeroInit(SectionPimpl, Result);
520}
521
522inline error_code SectionRef::isReadOnlyData(bool &Result) const {
523  return OwningObject->isSectionReadOnlyData(SectionPimpl, Result);
524}
525
526inline error_code SectionRef::containsSymbol(SymbolRef S, bool &Result) const {
527  return OwningObject->sectionContainsSymbol(SectionPimpl, S.SymbolPimpl,
528                                             Result);
529}
530
531inline relocation_iterator SectionRef::begin_relocations() const {
532  return OwningObject->getSectionRelBegin(SectionPimpl);
533}
534
535inline relocation_iterator SectionRef::end_relocations() const {
536  return OwningObject->getSectionRelEnd(SectionPimpl);
537}
538
539inline DataRefImpl SectionRef::getRawDataRefImpl() const {
540  return SectionPimpl;
541}
542
543/// RelocationRef
544inline RelocationRef::RelocationRef(DataRefImpl RelocationP,
545                              const ObjectFile *Owner)
546  : RelocationPimpl(RelocationP)
547  , OwningObject(Owner) {}
548
549inline bool RelocationRef::operator==(const RelocationRef &Other) const {
550  return RelocationPimpl == Other.RelocationPimpl;
551}
552
553inline error_code RelocationRef::getNext(RelocationRef &Result) const {
554  return OwningObject->getRelocationNext(RelocationPimpl, Result);
555}
556
557inline error_code RelocationRef::getAddress(uint64_t &Result) const {
558  return OwningObject->getRelocationAddress(RelocationPimpl, Result);
559}
560
561inline error_code RelocationRef::getOffset(uint64_t &Result) const {
562  return OwningObject->getRelocationOffset(RelocationPimpl, Result);
563}
564
565inline error_code RelocationRef::getSymbol(SymbolRef &Result) const {
566  return OwningObject->getRelocationSymbol(RelocationPimpl, Result);
567}
568
569inline error_code RelocationRef::getType(uint64_t &Result) const {
570  return OwningObject->getRelocationType(RelocationPimpl, Result);
571}
572
573inline error_code RelocationRef::getTypeName(SmallVectorImpl<char> &Result)
574  const {
575  return OwningObject->getRelocationTypeName(RelocationPimpl, Result);
576}
577
578inline error_code RelocationRef::getAdditionalInfo(int64_t &Result) const {
579  return OwningObject->getRelocationAdditionalInfo(RelocationPimpl, Result);
580}
581
582inline error_code RelocationRef::getValueString(SmallVectorImpl<char> &Result)
583  const {
584  return OwningObject->getRelocationValueString(RelocationPimpl, Result);
585}
586
587inline error_code RelocationRef::getHidden(bool &Result) const {
588  return OwningObject->getRelocationHidden(RelocationPimpl, Result);
589}
590
591inline DataRefImpl RelocationRef::getRawDataRefImpl() const {
592  return RelocationPimpl;
593}
594
595// Inline function definitions.
596inline LibraryRef::LibraryRef(DataRefImpl LibraryP, const ObjectFile *Owner)
597  : LibraryPimpl(LibraryP)
598  , OwningObject(Owner) {}
599
600inline bool LibraryRef::operator==(const LibraryRef &Other) const {
601  return LibraryPimpl == Other.LibraryPimpl;
602}
603
604inline bool LibraryRef::operator<(const LibraryRef &Other) const {
605  return LibraryPimpl < Other.LibraryPimpl;
606}
607
608inline error_code LibraryRef::getNext(LibraryRef &Result) const {
609  return OwningObject->getLibraryNext(LibraryPimpl, Result);
610}
611
612inline error_code LibraryRef::getPath(StringRef &Result) const {
613  return OwningObject->getLibraryPath(LibraryPimpl, Result);
614}
615
616} // end namespace object
617} // end namespace llvm
618
619#endif
620