ObjectFile.h revision 9b24738bd1dc791eb2c21b5562fcfe4b7b99fe2a 
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
24namespace llvm {
25namespace object {
26
27class ObjectFile;
28
29union DataRefImpl {
30  struct {
31    // ELF needs this for relocations. This entire union should probably be a
32    // char[max(8, sizeof(uintptr_t))] and require the impl to cast.
33    uint16_t a, b;
34    uint32_t c;
35  } w;
36  struct {
37    uint32_t a, b;
38  } d;
39  uintptr_t p;
40};
41
42template<class content_type>
43class content_iterator {
44  content_type Current;
45public:
46  content_iterator(content_type symb)
47    : Current(symb) {}
48
49  const content_type* operator->() const {
50    return &Current;
51  }
52
53  const content_type &operator*() const {
54    return Current;
55  }
56
57  bool operator==(const content_iterator &other) const {
58    return Current == other.Current;
59  }
60
61  bool operator!=(const content_iterator &other) const {
62    return !(*this == other);
63  }
64
65  content_iterator& increment(error_code &err) {
66    content_type next;
67    if (error_code ec = Current.getNext(next))
68      err = ec;
69    else
70      Current = next;
71    return *this;
72  }
73};
74
75static bool operator ==(const DataRefImpl &a, const DataRefImpl &b) {
76  // Check bitwise identical. This is the only legal way to compare a union w/o
77  // knowing which member is in use.
78  return std::memcmp(&a, &b, sizeof(DataRefImpl)) == 0;
79}
80
81static bool operator <(const DataRefImpl &a, const DataRefImpl &b) {
82  // Check bitwise identical. This is the only legal way to compare a union w/o
83  // knowing which member is in use.
84  return std::memcmp(&a, &b, sizeof(DataRefImpl)) < 0;
85}
86
87class SymbolRef;
88
89/// RelocationRef - This is a value type class that represents a single
90/// relocation in the list of relocations in the object file.
91class RelocationRef {
92  DataRefImpl RelocationPimpl;
93  const ObjectFile *OwningObject;
94
95public:
96  RelocationRef() : OwningObject(NULL) {
97    std::memset(&RelocationPimpl, 0, sizeof(RelocationPimpl));
98  }
99
100  RelocationRef(DataRefImpl RelocationP, const ObjectFile *Owner);
101
102  bool operator==(const RelocationRef &Other) const;
103
104  error_code getNext(RelocationRef &Result) const;
105
106  error_code getAddress(uint64_t &Result) const;
107  error_code getOffset(uint64_t &Result) const;
108  error_code getSymbol(SymbolRef &Result) const;
109  error_code getType(uint64_t &Result) const;
110
111  /// @brief Indicates whether this relocation should hidden when listing
112  /// relocations, usually because it is the trailing part of a multipart
113  /// relocation that will be printed as part of the leading relocation.
114  error_code getHidden(bool &Result) const;
115
116  /// @brief Get a string that represents the type of this relocation.
117  ///
118  /// This is for display purposes only.
119  error_code getTypeName(SmallVectorImpl<char> &Result) const;
120  error_code getAdditionalInfo(int64_t &Result) const;
121
122  /// @brief Get a string that represents the calculation of the value of this
123  ///        relocation.
124  ///
125  /// This is for display purposes only.
126  error_code getValueString(SmallVectorImpl<char> &Result) const;
127};
128typedef content_iterator<RelocationRef> relocation_iterator;
129
130/// SectionRef - This is a value type class that represents a single section in
131/// the list of sections in the object file.
132class SectionRef {
133  friend class SymbolRef;
134  DataRefImpl SectionPimpl;
135  const ObjectFile *OwningObject;
136
137public:
138  SectionRef() : OwningObject(NULL) {
139    std::memset(&SectionPimpl, 0, sizeof(SectionPimpl));
140  }
141
142  SectionRef(DataRefImpl SectionP, const ObjectFile *Owner);
143
144  bool operator==(const SectionRef &Other) const;
145  bool operator <(const SectionRef &Other) const;
146
147  error_code getNext(SectionRef &Result) const;
148
149  error_code getName(StringRef &Result) const;
150  error_code getAddress(uint64_t &Result) const;
151  error_code getSize(uint64_t &Result) const;
152  error_code getContents(StringRef &Result) const;
153
154  /// @brief Get the alignment of this section as the actual value (not log 2).
155  error_code getAlignment(uint64_t &Result) const;
156
157  // FIXME: Move to the normalization layer when it's created.
158  error_code isText(bool &Result) const;
159  error_code isData(bool &Result) const;
160  error_code isBSS(bool &Result) const;
161
162  error_code containsSymbol(SymbolRef S, bool &Result) const;
163
164  relocation_iterator begin_relocations() const;
165  relocation_iterator end_relocations() const;
166};
167typedef content_iterator<SectionRef> section_iterator;
168
169/// SymbolRef - This is a value type class that represents a single symbol in
170/// the list of symbols in the object file.
171class SymbolRef {
172  friend class SectionRef;
173  DataRefImpl SymbolPimpl;
174  const ObjectFile *OwningObject;
175
176public:
177  SymbolRef() : OwningObject(NULL) {
178    std::memset(&SymbolPimpl, 0, sizeof(SymbolPimpl));
179  }
180
181  enum Type {
182    ST_Data,
183    ST_Debug,
184    ST_External,    // Defined in another object file
185    ST_File,
186    ST_Function,
187    ST_Other
188  };
189
190  SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner);
191
192  bool operator==(const SymbolRef &Other) const;
193  bool operator <(const SymbolRef &Other) const;
194
195  error_code getNext(SymbolRef &Result) const;
196
197  error_code getName(StringRef &Result) const;
198  error_code getAddress(uint64_t &Result) const;
199  error_code getFileOffset(uint64_t &Result) const;
200  error_code getSize(uint64_t &Result) const;
201  error_code getType(SymbolRef::Type &Result) const;
202
203  /// Returns the ascii char that should be displayed in a symbol table dump via
204  /// nm for this symbol.
205  error_code getNMTypeChar(char &Result) const;
206
207  /// Returns true for symbols that are internal to the object file format such
208  /// as section symbols.
209  error_code isInternal(bool &Result) const;
210
211  /// Returns true for symbols that can be used in another objects,
212  /// such as library functions
213  error_code isGlobal(bool &Result) const;
214
215  /// Returns true for weak symbols.
216  error_code isWeak(bool &Result) const;
217
218  /// @brief Return true for absolute symbols.
219  error_code isAbsolute(bool &Result) const;
220
221  /// @brief Get section this symbol is defined in reference to. Result is
222  /// end_sections() if it is undefined or is an absolute symbol.
223  error_code getSection(section_iterator &Result) const;
224
225  DataRefImpl getRawDataRefImpl() const;
226};
227typedef content_iterator<SymbolRef> symbol_iterator;
228
229const uint64_t UnknownAddressOrSize = ~0ULL;
230
231/// ObjectFile - This class is the base class for all object file types.
232/// Concrete instances of this object are created by createObjectFile, which
233/// figure out which type to create.
234class ObjectFile : public Binary {
235private:
236  ObjectFile(); // = delete
237  ObjectFile(const ObjectFile &other); // = delete
238
239protected:
240  ObjectFile(unsigned int Type, MemoryBuffer *source, error_code &ec);
241
242  const uint8_t *base() const {
243    return reinterpret_cast<const uint8_t *>(Data->getBufferStart());
244  }
245
246  // These functions are for SymbolRef to call internally. The main goal of
247  // this is to allow SymbolRef::SymbolPimpl to point directly to the symbol
248  // entry in the memory mapped object file. SymbolPimpl cannot contain any
249  // virtual functions because then it could not point into the memory mapped
250  // file.
251  //
252  // Implementations assume that the DataRefImpl is valid and has not been
253  // modified externally. It's UB otherwise.
254  friend class SymbolRef;
255  virtual error_code getSymbolNext(DataRefImpl Symb, SymbolRef &Res) const = 0;
256  virtual error_code getSymbolName(DataRefImpl Symb, StringRef &Res) const = 0;
257  virtual error_code getSymbolAddress(DataRefImpl Symb, uint64_t &Res) const =0;
258  virtual error_code getSymbolFileOffset(DataRefImpl Symb, uint64_t &Res) const =0;
259  virtual error_code getSymbolSize(DataRefImpl Symb, uint64_t &Res) const = 0;
260  virtual error_code getSymbolType(DataRefImpl Symb,
261                                   SymbolRef::Type &Res) const = 0;
262  virtual error_code getSymbolNMTypeChar(DataRefImpl Symb, char &Res) const = 0;
263  virtual error_code isSymbolInternal(DataRefImpl Symb, bool &Res) const = 0;
264  virtual error_code isSymbolGlobal(DataRefImpl Symb, bool &Res) const = 0;
265  virtual error_code isSymbolWeak(DataRefImpl Symb, bool &Res) const = 0;
266  virtual error_code isSymbolAbsolute(DataRefImpl Symb, bool &Res) const = 0;
267  virtual error_code getSymbolSection(DataRefImpl Symb,
268                                      section_iterator &Res) const = 0;
269
270  // Same as above for SectionRef.
271  friend class SectionRef;
272  virtual error_code getSectionNext(DataRefImpl Sec, SectionRef &Res) const = 0;
273  virtual error_code getSectionName(DataRefImpl Sec, StringRef &Res) const = 0;
274  virtual error_code getSectionAddress(DataRefImpl Sec, uint64_t &Res) const =0;
275  virtual error_code getSectionSize(DataRefImpl Sec, uint64_t &Res) const = 0;
276  virtual error_code getSectionContents(DataRefImpl Sec, StringRef &Res)const=0;
277  virtual error_code getSectionAlignment(DataRefImpl Sec, uint64_t &Res)const=0;
278  virtual error_code isSectionText(DataRefImpl Sec, bool &Res) const = 0;
279  virtual error_code isSectionData(DataRefImpl Sec, bool &Res) const = 0;
280  virtual error_code isSectionBSS(DataRefImpl Sec, bool &Res) const = 0;
281  virtual error_code sectionContainsSymbol(DataRefImpl Sec, DataRefImpl Symb,
282                                           bool &Result) const = 0;
283  virtual relocation_iterator getSectionRelBegin(DataRefImpl Sec) const = 0;
284  virtual relocation_iterator getSectionRelEnd(DataRefImpl Sec) const = 0;
285
286
287  // Same as above for RelocationRef.
288  friend class RelocationRef;
289  virtual error_code getRelocationNext(DataRefImpl Rel,
290                                       RelocationRef &Res) const = 0;
291  virtual error_code getRelocationAddress(DataRefImpl Rel,
292                                          uint64_t &Res) const =0;
293  virtual error_code getRelocationOffset(DataRefImpl Rel,
294                                         uint64_t &Res) const =0;
295  virtual error_code getRelocationSymbol(DataRefImpl Rel,
296                                         SymbolRef &Res) const = 0;
297  virtual error_code getRelocationType(DataRefImpl Rel,
298                                       uint64_t &Res) const = 0;
299  virtual error_code getRelocationTypeName(DataRefImpl Rel,
300                                       SmallVectorImpl<char> &Result) const = 0;
301  virtual error_code getRelocationAdditionalInfo(DataRefImpl Rel,
302                                                 int64_t &Res) const = 0;
303  virtual error_code getRelocationValueString(DataRefImpl Rel,
304                                       SmallVectorImpl<char> &Result) const = 0;
305  virtual error_code getRelocationHidden(DataRefImpl Rel, bool &Result) const {
306    Result = false;
307    return object_error::success;
308  }
309
310public:
311
312  virtual symbol_iterator begin_symbols() const = 0;
313  virtual symbol_iterator end_symbols() const = 0;
314
315  virtual section_iterator begin_sections() const = 0;
316  virtual section_iterator end_sections() const = 0;
317
318  /// @brief The number of bytes used to represent an address in this object
319  ///        file format.
320  virtual uint8_t getBytesInAddress() const = 0;
321
322  virtual StringRef getFileFormatName() const = 0;
323  virtual /* Triple::ArchType */ unsigned getArch() const = 0;
324
325  /// @returns Pointer to ObjectFile subclass to handle this type of object.
326  /// @param ObjectPath The path to the object file. ObjectPath.isObject must
327  ///        return true.
328  /// @brief Create ObjectFile from path.
329  static ObjectFile *createObjectFile(StringRef ObjectPath);
330  static ObjectFile *createObjectFile(MemoryBuffer *Object);
331
332  static inline bool classof(const Binary *v) {
333    return v->getType() >= isObject &&
334           v->getType() < lastObject;
335  }
336  static inline bool classof(const ObjectFile *v) { return true; }
337
338public:
339  static ObjectFile *createCOFFObjectFile(MemoryBuffer *Object);
340  static ObjectFile *createELFObjectFile(MemoryBuffer *Object);
341  static ObjectFile *createMachOObjectFile(MemoryBuffer *Object);
342};
343
344// Inline function definitions.
345inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner)
346  : SymbolPimpl(SymbolP)
347  , OwningObject(Owner) {}
348
349inline bool SymbolRef::operator==(const SymbolRef &Other) const {
350  return SymbolPimpl == Other.SymbolPimpl;
351}
352
353inline bool SymbolRef::operator <(const SymbolRef &Other) const {
354  return SymbolPimpl < Other.SymbolPimpl;
355}
356
357inline error_code SymbolRef::getNext(SymbolRef &Result) const {
358  return OwningObject->getSymbolNext(SymbolPimpl, Result);
359}
360
361inline error_code SymbolRef::getName(StringRef &Result) const {
362  return OwningObject->getSymbolName(SymbolPimpl, Result);
363}
364
365inline error_code SymbolRef::getAddress(uint64_t &Result) const {
366  return OwningObject->getSymbolAddress(SymbolPimpl, Result);
367}
368
369inline error_code SymbolRef::getFileOffset(uint64_t &Result) const {
370  return OwningObject->getSymbolFileOffset(SymbolPimpl, Result);
371}
372
373inline error_code SymbolRef::getSize(uint64_t &Result) const {
374  return OwningObject->getSymbolSize(SymbolPimpl, Result);
375}
376
377inline error_code SymbolRef::getNMTypeChar(char &Result) const {
378  return OwningObject->getSymbolNMTypeChar(SymbolPimpl, Result);
379}
380
381inline error_code SymbolRef::isInternal(bool &Result) const {
382  return OwningObject->isSymbolInternal(SymbolPimpl, Result);
383}
384
385inline error_code SymbolRef::isGlobal(bool &Result) const {
386  return OwningObject->isSymbolGlobal(SymbolPimpl, Result);
387}
388
389inline error_code SymbolRef::isWeak(bool &Result) const {
390  return OwningObject->isSymbolWeak(SymbolPimpl, Result);
391}
392
393inline error_code SymbolRef::isAbsolute(bool &Result) const {
394  return OwningObject->isSymbolAbsolute(SymbolPimpl, Result);
395}
396
397inline error_code SymbolRef::getSection(section_iterator &Result) const {
398  return OwningObject->getSymbolSection(SymbolPimpl, Result);
399}
400
401inline error_code SymbolRef::getType(SymbolRef::Type &Result) const {
402  return OwningObject->getSymbolType(SymbolPimpl, Result);
403}
404
405inline DataRefImpl SymbolRef::getRawDataRefImpl() const {
406  return SymbolPimpl;
407}
408
409
410/// SectionRef
411inline SectionRef::SectionRef(DataRefImpl SectionP,
412                              const ObjectFile *Owner)
413  : SectionPimpl(SectionP)
414  , OwningObject(Owner) {}
415
416inline bool SectionRef::operator==(const SectionRef &Other) const {
417  return SectionPimpl == Other.SectionPimpl;
418}
419
420inline bool SectionRef::operator <(const SectionRef &Other) const {
421  return SectionPimpl < Other.SectionPimpl;
422}
423
424inline error_code SectionRef::getNext(SectionRef &Result) const {
425  return OwningObject->getSectionNext(SectionPimpl, Result);
426}
427
428inline error_code SectionRef::getName(StringRef &Result) const {
429  return OwningObject->getSectionName(SectionPimpl, Result);
430}
431
432inline error_code SectionRef::getAddress(uint64_t &Result) const {
433  return OwningObject->getSectionAddress(SectionPimpl, Result);
434}
435
436inline error_code SectionRef::getSize(uint64_t &Result) const {
437  return OwningObject->getSectionSize(SectionPimpl, Result);
438}
439
440inline error_code SectionRef::getContents(StringRef &Result) const {
441  return OwningObject->getSectionContents(SectionPimpl, Result);
442}
443
444inline error_code SectionRef::getAlignment(uint64_t &Result) const {
445  return OwningObject->getSectionAlignment(SectionPimpl, Result);
446}
447
448inline error_code SectionRef::isText(bool &Result) const {
449  return OwningObject->isSectionText(SectionPimpl, Result);
450}
451
452inline error_code SectionRef::isData(bool &Result) const {
453  return OwningObject->isSectionData(SectionPimpl, Result);
454}
455
456inline error_code SectionRef::isBSS(bool &Result) const {
457  return OwningObject->isSectionBSS(SectionPimpl, Result);
458}
459
460inline error_code SectionRef::containsSymbol(SymbolRef S, bool &Result) const {
461  return OwningObject->sectionContainsSymbol(SectionPimpl, S.SymbolPimpl,
462                                             Result);
463}
464
465inline relocation_iterator SectionRef::begin_relocations() const {
466  return OwningObject->getSectionRelBegin(SectionPimpl);
467}
468
469inline relocation_iterator SectionRef::end_relocations() const {
470  return OwningObject->getSectionRelEnd(SectionPimpl);
471}
472
473
474/// RelocationRef
475inline RelocationRef::RelocationRef(DataRefImpl RelocationP,
476                              const ObjectFile *Owner)
477  : RelocationPimpl(RelocationP)
478  , OwningObject(Owner) {}
479
480inline bool RelocationRef::operator==(const RelocationRef &Other) const {
481  return RelocationPimpl == Other.RelocationPimpl;
482}
483
484inline error_code RelocationRef::getNext(RelocationRef &Result) const {
485  return OwningObject->getRelocationNext(RelocationPimpl, Result);
486}
487
488inline error_code RelocationRef::getAddress(uint64_t &Result) const {
489  return OwningObject->getRelocationAddress(RelocationPimpl, Result);
490}
491
492inline error_code RelocationRef::getOffset(uint64_t &Result) const {
493  return OwningObject->getRelocationOffset(RelocationPimpl, Result);
494}
495
496inline error_code RelocationRef::getSymbol(SymbolRef &Result) const {
497  return OwningObject->getRelocationSymbol(RelocationPimpl, Result);
498}
499
500inline error_code RelocationRef::getType(uint64_t &Result) const {
501  return OwningObject->getRelocationType(RelocationPimpl, Result);
502}
503
504inline error_code RelocationRef::getTypeName(SmallVectorImpl<char> &Result)
505  const {
506  return OwningObject->getRelocationTypeName(RelocationPimpl, Result);
507}
508
509inline error_code RelocationRef::getAdditionalInfo(int64_t &Result) const {
510  return OwningObject->getRelocationAdditionalInfo(RelocationPimpl, Result);
511}
512
513inline error_code RelocationRef::getValueString(SmallVectorImpl<char> &Result)
514  const {
515  return OwningObject->getRelocationValueString(RelocationPimpl, Result);
516}
517
518inline error_code RelocationRef::getHidden(bool &Result) const {
519  return OwningObject->getRelocationHidden(RelocationPimpl, Result);
520}
521
522} // end namespace object
523} // end namespace llvm
524
525#endif
526