ObjectFile.h revision 9ac0f1d7255d7941c331b0a62a830a3b033358fd 
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/Object/Binary.h"
18#include "llvm/ADT/StringRef.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
79static 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
85static 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
167  error_code containsSymbol(SymbolRef S, bool &Result) const;
168
169  relocation_iterator begin_relocations() const;
170  relocation_iterator end_relocations() const;
171
172  DataRefImpl getRawDataRefImpl() const;
173};
174typedef content_iterator<SectionRef> section_iterator;
175
176/// SymbolRef - This is a value type class that represents a single symbol in
177/// the list of symbols in the object file.
178class SymbolRef {
179  friend class SectionRef;
180  DataRefImpl SymbolPimpl;
181  const ObjectFile *OwningObject;
182
183public:
184  SymbolRef() : OwningObject(NULL) { }
185
186  enum Type {
187    ST_Unknown, // Type not specified
188    ST_Data,
189    ST_Debug,
190    ST_File,
191    ST_Function,
192    ST_Other
193  };
194
195  enum Flags {
196    SF_None            = 0,
197    SF_Undefined       = 1U << 0,  // Symbol is defined in another object file
198    SF_Global          = 1U << 1,  // Global symbol
199    SF_Weak            = 1U << 2,  // Weak symbol
200    SF_Absolute        = 1U << 3,  // Absolute symbol
201    SF_ThreadLocal     = 1U << 4,  // Thread local symbol
202    SF_Common          = 1U << 5,  // Symbol has common linkage
203    SF_FormatSpecific  = 1U << 31  // Specific to the object file format
204                                   // (e.g. section symbols)
205  };
206
207  SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner);
208
209  bool operator==(const SymbolRef &Other) const;
210  bool operator <(const SymbolRef &Other) const;
211
212  error_code getNext(SymbolRef &Result) const;
213
214  error_code getName(StringRef &Result) const;
215  error_code getAddress(uint64_t &Result) const;
216  error_code getFileOffset(uint64_t &Result) const;
217  error_code getSize(uint64_t &Result) const;
218  error_code getType(SymbolRef::Type &Result) const;
219
220  /// Returns the ascii char that should be displayed in a symbol table dump via
221  /// nm for this symbol.
222  error_code getNMTypeChar(char &Result) const;
223
224  /// Get symbol flags (bitwise OR of SymbolRef::Flags)
225  error_code getFlags(uint32_t &Result) const;
226
227  /// @brief Return true for common symbols such as uninitialized globals
228  error_code isCommon(bool &Result) const;
229
230  /// @brief Get section this symbol is defined in reference to. Result is
231  /// end_sections() if it is undefined or is an absolute symbol.
232  error_code getSection(section_iterator &Result) const;
233
234  DataRefImpl getRawDataRefImpl() const;
235};
236typedef content_iterator<SymbolRef> symbol_iterator;
237
238/// LibraryRef - This is a value type class that represents a single library in
239/// the list of libraries needed by a shared or dynamic object.
240class LibraryRef {
241  friend class SectionRef;
242  DataRefImpl LibraryPimpl;
243  const ObjectFile *OwningObject;
244
245public:
246  LibraryRef() : OwningObject(NULL) { }
247
248  LibraryRef(DataRefImpl LibraryP, const ObjectFile *Owner);
249
250  bool operator==(const LibraryRef &Other) const;
251  bool operator <(const LibraryRef &Other) const;
252
253  error_code getNext(LibraryRef &Result) const;
254
255  // Get the path to this library, as stored in the object file.
256  error_code getPath(StringRef &Result) const;
257
258  DataRefImpl getRawDataRefImpl() const;
259};
260typedef content_iterator<LibraryRef> library_iterator;
261
262const uint64_t UnknownAddressOrSize = ~0ULL;
263
264/// ObjectFile - This class is the base class for all object file types.
265/// Concrete instances of this object are created by createObjectFile, which
266/// figure out which type to create.
267class ObjectFile : public Binary {
268  virtual void anchor();
269  ObjectFile(); // = delete
270  ObjectFile(const ObjectFile &other); // = delete
271
272protected:
273  ObjectFile(unsigned int Type, MemoryBuffer *source, error_code &ec);
274
275  const uint8_t *base() const {
276    return reinterpret_cast<const uint8_t *>(Data->getBufferStart());
277  }
278
279  // These functions are for SymbolRef to call internally. The main goal of
280  // this is to allow SymbolRef::SymbolPimpl to point directly to the symbol
281  // entry in the memory mapped object file. SymbolPimpl cannot contain any
282  // virtual functions because then it could not point into the memory mapped
283  // file.
284  //
285  // Implementations assume that the DataRefImpl is valid and has not been
286  // modified externally. It's UB otherwise.
287  friend class SymbolRef;
288  virtual error_code getSymbolNext(DataRefImpl Symb, SymbolRef &Res) const = 0;
289  virtual error_code getSymbolName(DataRefImpl Symb, StringRef &Res) const = 0;
290  virtual error_code getSymbolAddress(DataRefImpl Symb, uint64_t &Res) const =0;
291  virtual error_code getSymbolFileOffset(DataRefImpl Symb, uint64_t &Res) const =0;
292  virtual error_code getSymbolSize(DataRefImpl Symb, uint64_t &Res) const = 0;
293  virtual error_code getSymbolType(DataRefImpl Symb,
294                                   SymbolRef::Type &Res) const = 0;
295  virtual error_code getSymbolNMTypeChar(DataRefImpl Symb, char &Res) const = 0;
296  virtual error_code getSymbolFlags(DataRefImpl Symb,
297                                    uint32_t &Res) const = 0;
298  virtual error_code getSymbolSection(DataRefImpl Symb,
299                                      section_iterator &Res) const = 0;
300
301  // Same as above for SectionRef.
302  friend class SectionRef;
303  virtual error_code getSectionNext(DataRefImpl Sec, SectionRef &Res) const = 0;
304  virtual error_code getSectionName(DataRefImpl Sec, StringRef &Res) const = 0;
305  virtual error_code getSectionAddress(DataRefImpl Sec, uint64_t &Res) const =0;
306  virtual error_code getSectionSize(DataRefImpl Sec, uint64_t &Res) const = 0;
307  virtual error_code getSectionContents(DataRefImpl Sec, StringRef &Res)const=0;
308  virtual error_code getSectionAlignment(DataRefImpl Sec, uint64_t &Res)const=0;
309  virtual error_code isSectionText(DataRefImpl Sec, bool &Res) const = 0;
310  virtual error_code isSectionData(DataRefImpl Sec, bool &Res) const = 0;
311  virtual error_code isSectionBSS(DataRefImpl Sec, bool &Res) const = 0;
312  virtual error_code isSectionRequiredForExecution(DataRefImpl Sec,
313                                                   bool &Res) const = 0;
314  // A section is 'virtual' if its contents aren't present in the object image.
315  virtual error_code isSectionVirtual(DataRefImpl Sec, bool &Res) const = 0;
316  virtual error_code isSectionZeroInit(DataRefImpl Sec, bool &Res) const = 0;
317  virtual error_code sectionContainsSymbol(DataRefImpl Sec, DataRefImpl Symb,
318                                           bool &Result) const = 0;
319  virtual relocation_iterator getSectionRelBegin(DataRefImpl Sec) const = 0;
320  virtual relocation_iterator getSectionRelEnd(DataRefImpl Sec) const = 0;
321
322
323  // Same as above for RelocationRef.
324  friend class RelocationRef;
325  virtual error_code getRelocationNext(DataRefImpl Rel,
326                                       RelocationRef &Res) const = 0;
327  virtual error_code getRelocationAddress(DataRefImpl Rel,
328                                          uint64_t &Res) const =0;
329  virtual error_code getRelocationOffset(DataRefImpl Rel,
330                                         uint64_t &Res) const =0;
331  virtual error_code getRelocationSymbol(DataRefImpl Rel,
332                                         SymbolRef &Res) const = 0;
333  virtual error_code getRelocationType(DataRefImpl Rel,
334                                       uint64_t &Res) const = 0;
335  virtual error_code getRelocationTypeName(DataRefImpl Rel,
336                                       SmallVectorImpl<char> &Result) const = 0;
337  virtual error_code getRelocationAdditionalInfo(DataRefImpl Rel,
338                                                 int64_t &Res) const = 0;
339  virtual error_code getRelocationValueString(DataRefImpl Rel,
340                                       SmallVectorImpl<char> &Result) const = 0;
341  virtual error_code getRelocationHidden(DataRefImpl Rel, bool &Result) const {
342    Result = false;
343    return object_error::success;
344  }
345
346  // Same for LibraryRef
347  friend class LibraryRef;
348  virtual error_code getLibraryNext(DataRefImpl Lib, LibraryRef &Res) const = 0;
349  virtual error_code getLibraryPath(DataRefImpl Lib, StringRef &Res) const = 0;
350
351public:
352
353  virtual symbol_iterator begin_symbols() const = 0;
354  virtual symbol_iterator end_symbols() const = 0;
355
356  virtual symbol_iterator begin_dynamic_symbols() const = 0;
357  virtual symbol_iterator end_dynamic_symbols() const = 0;
358
359  virtual section_iterator begin_sections() const = 0;
360  virtual section_iterator end_sections() const = 0;
361
362  virtual library_iterator begin_libraries_needed() const = 0;
363  virtual library_iterator end_libraries_needed() const = 0;
364
365  /// @brief The number of bytes used to represent an address in this object
366  ///        file format.
367  virtual uint8_t getBytesInAddress() const = 0;
368
369  virtual StringRef getFileFormatName() const = 0;
370  virtual /* Triple::ArchType */ unsigned getArch() const = 0;
371
372  /// For shared objects, returns the name which this object should be
373  /// loaded from at runtime. This corresponds to DT_SONAME on ELF and
374  /// LC_ID_DYLIB (install name) on MachO.
375  virtual StringRef getLoadName() const = 0;
376
377  /// @returns Pointer to ObjectFile subclass to handle this type of object.
378  /// @param ObjectPath The path to the object file. ObjectPath.isObject must
379  ///        return true.
380  /// @brief Create ObjectFile from path.
381  static ObjectFile *createObjectFile(StringRef ObjectPath);
382  static ObjectFile *createObjectFile(MemoryBuffer *Object);
383
384  static inline bool classof(const Binary *v) {
385    return v->isObject();
386  }
387  static inline bool classof(const ObjectFile *v) { return true; }
388
389public:
390  static ObjectFile *createCOFFObjectFile(MemoryBuffer *Object);
391  static ObjectFile *createELFObjectFile(MemoryBuffer *Object);
392  static ObjectFile *createMachOObjectFile(MemoryBuffer *Object);
393};
394
395// Inline function definitions.
396inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner)
397  : SymbolPimpl(SymbolP)
398  , OwningObject(Owner) {}
399
400inline bool SymbolRef::operator==(const SymbolRef &Other) const {
401  return SymbolPimpl == Other.SymbolPimpl;
402}
403
404inline bool SymbolRef::operator <(const SymbolRef &Other) const {
405  return SymbolPimpl < Other.SymbolPimpl;
406}
407
408inline error_code SymbolRef::getNext(SymbolRef &Result) const {
409  return OwningObject->getSymbolNext(SymbolPimpl, Result);
410}
411
412inline error_code SymbolRef::getName(StringRef &Result) const {
413  return OwningObject->getSymbolName(SymbolPimpl, Result);
414}
415
416inline error_code SymbolRef::getAddress(uint64_t &Result) const {
417  return OwningObject->getSymbolAddress(SymbolPimpl, Result);
418}
419
420inline error_code SymbolRef::getFileOffset(uint64_t &Result) const {
421  return OwningObject->getSymbolFileOffset(SymbolPimpl, Result);
422}
423
424inline error_code SymbolRef::getSize(uint64_t &Result) const {
425  return OwningObject->getSymbolSize(SymbolPimpl, Result);
426}
427
428inline error_code SymbolRef::getNMTypeChar(char &Result) const {
429  return OwningObject->getSymbolNMTypeChar(SymbolPimpl, Result);
430}
431
432inline error_code SymbolRef::getFlags(uint32_t &Result) const {
433  return OwningObject->getSymbolFlags(SymbolPimpl, Result);
434}
435
436inline error_code SymbolRef::getSection(section_iterator &Result) const {
437  return OwningObject->getSymbolSection(SymbolPimpl, Result);
438}
439
440inline error_code SymbolRef::getType(SymbolRef::Type &Result) const {
441  return OwningObject->getSymbolType(SymbolPimpl, Result);
442}
443
444inline DataRefImpl SymbolRef::getRawDataRefImpl() const {
445  return SymbolPimpl;
446}
447
448
449/// SectionRef
450inline SectionRef::SectionRef(DataRefImpl SectionP,
451                              const ObjectFile *Owner)
452  : SectionPimpl(SectionP)
453  , OwningObject(Owner) {}
454
455inline bool SectionRef::operator==(const SectionRef &Other) const {
456  return SectionPimpl == Other.SectionPimpl;
457}
458
459inline bool SectionRef::operator <(const SectionRef &Other) const {
460  return SectionPimpl < Other.SectionPimpl;
461}
462
463inline error_code SectionRef::getNext(SectionRef &Result) const {
464  return OwningObject->getSectionNext(SectionPimpl, Result);
465}
466
467inline error_code SectionRef::getName(StringRef &Result) const {
468  return OwningObject->getSectionName(SectionPimpl, Result);
469}
470
471inline error_code SectionRef::getAddress(uint64_t &Result) const {
472  return OwningObject->getSectionAddress(SectionPimpl, Result);
473}
474
475inline error_code SectionRef::getSize(uint64_t &Result) const {
476  return OwningObject->getSectionSize(SectionPimpl, Result);
477}
478
479inline error_code SectionRef::getContents(StringRef &Result) const {
480  return OwningObject->getSectionContents(SectionPimpl, Result);
481}
482
483inline error_code SectionRef::getAlignment(uint64_t &Result) const {
484  return OwningObject->getSectionAlignment(SectionPimpl, Result);
485}
486
487inline error_code SectionRef::isText(bool &Result) const {
488  return OwningObject->isSectionText(SectionPimpl, Result);
489}
490
491inline error_code SectionRef::isData(bool &Result) const {
492  return OwningObject->isSectionData(SectionPimpl, Result);
493}
494
495inline error_code SectionRef::isBSS(bool &Result) const {
496  return OwningObject->isSectionBSS(SectionPimpl, Result);
497}
498
499inline error_code SectionRef::isRequiredForExecution(bool &Result) const {
500  return OwningObject->isSectionRequiredForExecution(SectionPimpl, Result);
501}
502
503inline error_code SectionRef::isVirtual(bool &Result) const {
504  return OwningObject->isSectionVirtual(SectionPimpl, Result);
505}
506
507inline error_code SectionRef::isZeroInit(bool &Result) const {
508  return OwningObject->isSectionZeroInit(SectionPimpl, Result);
509}
510
511inline error_code SectionRef::containsSymbol(SymbolRef S, bool &Result) const {
512  return OwningObject->sectionContainsSymbol(SectionPimpl, S.SymbolPimpl,
513                                             Result);
514}
515
516inline relocation_iterator SectionRef::begin_relocations() const {
517  return OwningObject->getSectionRelBegin(SectionPimpl);
518}
519
520inline relocation_iterator SectionRef::end_relocations() const {
521  return OwningObject->getSectionRelEnd(SectionPimpl);
522}
523
524inline DataRefImpl SectionRef::getRawDataRefImpl() const {
525  return SectionPimpl;
526}
527
528/// RelocationRef
529inline RelocationRef::RelocationRef(DataRefImpl RelocationP,
530                              const ObjectFile *Owner)
531  : RelocationPimpl(RelocationP)
532  , OwningObject(Owner) {}
533
534inline bool RelocationRef::operator==(const RelocationRef &Other) const {
535  return RelocationPimpl == Other.RelocationPimpl;
536}
537
538inline error_code RelocationRef::getNext(RelocationRef &Result) const {
539  return OwningObject->getRelocationNext(RelocationPimpl, Result);
540}
541
542inline error_code RelocationRef::getAddress(uint64_t &Result) const {
543  return OwningObject->getRelocationAddress(RelocationPimpl, Result);
544}
545
546inline error_code RelocationRef::getOffset(uint64_t &Result) const {
547  return OwningObject->getRelocationOffset(RelocationPimpl, Result);
548}
549
550inline error_code RelocationRef::getSymbol(SymbolRef &Result) const {
551  return OwningObject->getRelocationSymbol(RelocationPimpl, Result);
552}
553
554inline error_code RelocationRef::getType(uint64_t &Result) const {
555  return OwningObject->getRelocationType(RelocationPimpl, Result);
556}
557
558inline error_code RelocationRef::getTypeName(SmallVectorImpl<char> &Result)
559  const {
560  return OwningObject->getRelocationTypeName(RelocationPimpl, Result);
561}
562
563inline error_code RelocationRef::getAdditionalInfo(int64_t &Result) const {
564  return OwningObject->getRelocationAdditionalInfo(RelocationPimpl, Result);
565}
566
567inline error_code RelocationRef::getValueString(SmallVectorImpl<char> &Result)
568  const {
569  return OwningObject->getRelocationValueString(RelocationPimpl, Result);
570}
571
572inline error_code RelocationRef::getHidden(bool &Result) const {
573  return OwningObject->getRelocationHidden(RelocationPimpl, Result);
574}
575
576inline DataRefImpl RelocationRef::getRawDataRefImpl() const {
577  return RelocationPimpl;
578}
579
580// Inline function definitions.
581inline LibraryRef::LibraryRef(DataRefImpl LibraryP, const ObjectFile *Owner)
582  : LibraryPimpl(LibraryP)
583  , OwningObject(Owner) {}
584
585inline bool LibraryRef::operator==(const LibraryRef &Other) const {
586  return LibraryPimpl == Other.LibraryPimpl;
587}
588
589inline bool LibraryRef::operator <(const LibraryRef &Other) const {
590  return LibraryPimpl < Other.LibraryPimpl;
591}
592
593inline error_code LibraryRef::getNext(LibraryRef &Result) const {
594  return OwningObject->getLibraryNext(LibraryPimpl, Result);
595}
596
597inline error_code LibraryRef::getPath(StringRef &Result) const {
598  return OwningObject->getLibraryPath(LibraryPimpl, Result);
599}
600
601} // end namespace object
602} // end namespace llvm
603
604#endif
605