ObjectFile.h revision 2c10ecbe4c800bd8a2e1b3e05c4eedf75658b565 
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
81/// SymbolRef - This is a value type class that represents a single symbol in
82/// the list of symbols in the object file.
83class SymbolRef {
84  friend class SectionRef;
85  DataRefImpl SymbolPimpl;
86  const ObjectFile *OwningObject;
87
88public:
89  SymbolRef() : OwningObject(NULL) {
90    std::memset(&SymbolPimpl, 0, sizeof(SymbolPimpl));
91  }
92
93  enum Type {
94    ST_Function,
95    ST_Data,
96    ST_External,    // Defined in another object file
97    ST_Other
98  };
99
100  SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner);
101
102  bool operator==(const SymbolRef &Other) const;
103
104  error_code getNext(SymbolRef &Result) const;
105
106  error_code getName(StringRef &Result) const;
107  error_code getAddress(uint64_t &Result) const;
108  error_code getOffset(uint64_t &Result) const;
109  error_code getSize(uint64_t &Result) const;
110  error_code getType(SymbolRef::Type &Result) const;
111
112  /// Returns the ascii char that should be displayed in a symbol table dump via
113  /// nm for this symbol.
114  error_code getNMTypeChar(char &Result) const;
115
116  /// Returns true for symbols that are internal to the object file format such
117  /// as section symbols.
118  error_code isInternal(bool &Result) const;
119
120  /// Returns true for symbols that can be used in another objects,
121  /// such as library functions
122  error_code isGlobal(bool &Result) const;
123
124  DataRefImpl getRawDataRefImpl() const;
125};
126typedef content_iterator<SymbolRef> symbol_iterator;
127
128/// RelocationRef - This is a value type class that represents a single
129/// relocation in the list of relocations in the object file.
130class RelocationRef {
131  DataRefImpl RelocationPimpl;
132  const ObjectFile *OwningObject;
133
134public:
135  RelocationRef() : OwningObject(NULL) {
136    std::memset(&RelocationPimpl, 0, sizeof(RelocationPimpl));
137  }
138
139  RelocationRef(DataRefImpl RelocationP, const ObjectFile *Owner);
140
141  bool operator==(const RelocationRef &Other) const;
142
143  error_code getNext(RelocationRef &Result) const;
144
145  error_code getAddress(uint64_t &Result) const;
146  error_code getSymbol(SymbolRef &Result) const;
147  error_code getType(uint32_t &Result) const;
148
149  /// @brief Get a string that represents the type of this relocation.
150  ///
151  /// This is for display purposes only.
152  error_code getTypeName(SmallVectorImpl<char> &Result) const;
153  error_code getAdditionalInfo(int64_t &Result) const;
154
155  /// @brief Get a string that represents the calculation of the value of this
156  ///        relocation.
157  ///
158  /// This is for display purposes only.
159  error_code getValueString(SmallVectorImpl<char> &Result) const;
160};
161typedef content_iterator<RelocationRef> relocation_iterator;
162
163/// SectionRef - This is a value type class that represents a single section in
164/// the list of sections in the object file.
165class SectionRef {
166  friend class SymbolRef;
167  DataRefImpl SectionPimpl;
168  const ObjectFile *OwningObject;
169
170public:
171  SectionRef() : OwningObject(NULL) {
172    std::memset(&SectionPimpl, 0, sizeof(SectionPimpl));
173  }
174
175  SectionRef(DataRefImpl SectionP, const ObjectFile *Owner);
176
177  bool operator==(const SectionRef &Other) const;
178
179  error_code getNext(SectionRef &Result) const;
180
181  error_code getName(StringRef &Result) const;
182  error_code getAddress(uint64_t &Result) const;
183  error_code getSize(uint64_t &Result) const;
184  error_code getContents(StringRef &Result) const;
185
186  /// @brief Get the alignment of this section as the actual value (not log 2).
187  error_code getAlignment(uint64_t &Result) const;
188
189  // FIXME: Move to the normalization layer when it's created.
190  error_code isText(bool &Result) const;
191  error_code isData(bool &Result) const;
192  error_code isBSS(bool &Result) const;
193
194  error_code containsSymbol(SymbolRef S, bool &Result) const;
195
196  relocation_iterator begin_relocations() const;
197  relocation_iterator end_relocations() const;
198};
199typedef content_iterator<SectionRef> section_iterator;
200
201const uint64_t UnknownAddressOrSize = ~0ULL;
202
203/// ObjectFile - This class is the base class for all object file types.
204/// Concrete instances of this object are created by createObjectFile, which
205/// figure out which type to create.
206class ObjectFile : public Binary {
207private:
208  ObjectFile(); // = delete
209  ObjectFile(const ObjectFile &other); // = delete
210
211protected:
212  ObjectFile(unsigned int Type, MemoryBuffer *source, error_code &ec);
213
214  const uint8_t *base() const {
215    return reinterpret_cast<const uint8_t *>(Data->getBufferStart());
216  }
217
218  // These functions are for SymbolRef to call internally. The main goal of
219  // this is to allow SymbolRef::SymbolPimpl to point directly to the symbol
220  // entry in the memory mapped object file. SymbolPimpl cannot contain any
221  // virtual functions because then it could not point into the memory mapped
222  // file.
223  //
224  // Implementations assume that the DataRefImpl is valid and has not been
225  // modified externally. It's UB otherwise.
226  friend class SymbolRef;
227  virtual error_code getSymbolNext(DataRefImpl Symb, SymbolRef &Res) const = 0;
228  virtual error_code getSymbolName(DataRefImpl Symb, StringRef &Res) const = 0;
229  virtual error_code getSymbolAddress(DataRefImpl Symb, uint64_t &Res) const =0;
230  virtual error_code getSymbolOffset(DataRefImpl Symb, uint64_t &Res) const =0;
231  virtual error_code getSymbolSize(DataRefImpl Symb, uint64_t &Res) const = 0;
232  virtual error_code getSymbolType(DataRefImpl Symb,
233                                   SymbolRef::Type &Res) const = 0;
234  virtual error_code getSymbolNMTypeChar(DataRefImpl Symb, char &Res) const = 0;
235  virtual error_code isSymbolInternal(DataRefImpl Symb, bool &Res) const = 0;
236  virtual error_code isSymbolGlobal(DataRefImpl Symb, bool &Res) const = 0;
237
238
239  // Same as above for SectionRef.
240  friend class SectionRef;
241  virtual error_code getSectionNext(DataRefImpl Sec, SectionRef &Res) const = 0;
242  virtual error_code getSectionName(DataRefImpl Sec, StringRef &Res) const = 0;
243  virtual error_code getSectionAddress(DataRefImpl Sec, uint64_t &Res) const =0;
244  virtual error_code getSectionSize(DataRefImpl Sec, uint64_t &Res) const = 0;
245  virtual error_code getSectionContents(DataRefImpl Sec, StringRef &Res)const=0;
246  virtual error_code getSectionAlignment(DataRefImpl Sec, uint64_t &Res)const=0;
247  virtual error_code isSectionText(DataRefImpl Sec, bool &Res) const = 0;
248  virtual error_code isSectionData(DataRefImpl Sec, bool &Res) const = 0;
249  virtual error_code isSectionBSS(DataRefImpl Sec, bool &Res) const = 0;
250  virtual error_code sectionContainsSymbol(DataRefImpl Sec, DataRefImpl Symb,
251                                           bool &Result) const = 0;
252  virtual relocation_iterator getSectionRelBegin(DataRefImpl Sec) const = 0;
253  virtual relocation_iterator getSectionRelEnd(DataRefImpl Sec) const = 0;
254
255
256  // Same as above for RelocationRef.
257  friend class RelocationRef;
258  virtual error_code getRelocationNext(DataRefImpl Rel,
259                                       RelocationRef &Res) const = 0;
260  virtual error_code getRelocationAddress(DataRefImpl Rel,
261                                          uint64_t &Res) const =0;
262  virtual error_code getRelocationSymbol(DataRefImpl Rel,
263                                         SymbolRef &Res) const = 0;
264  virtual error_code getRelocationType(DataRefImpl Rel,
265                                       uint32_t &Res) const = 0;
266  virtual error_code getRelocationTypeName(DataRefImpl Rel,
267                                       SmallVectorImpl<char> &Result) const = 0;
268  virtual error_code getRelocationAdditionalInfo(DataRefImpl Rel,
269                                                 int64_t &Res) const = 0;
270  virtual error_code getRelocationValueString(DataRefImpl Rel,
271                                       SmallVectorImpl<char> &Result) const = 0;
272
273public:
274
275  virtual symbol_iterator begin_symbols() const = 0;
276  virtual symbol_iterator end_symbols() const = 0;
277
278  virtual section_iterator begin_sections() const = 0;
279  virtual section_iterator end_sections() const = 0;
280
281  /// @brief The number of bytes used to represent an address in this object
282  ///        file format.
283  virtual uint8_t getBytesInAddress() const = 0;
284
285  virtual StringRef getFileFormatName() const = 0;
286  virtual /* Triple::ArchType */ unsigned getArch() const = 0;
287
288  /// @returns Pointer to ObjectFile subclass to handle this type of object.
289  /// @param ObjectPath The path to the object file. ObjectPath.isObject must
290  ///        return true.
291  /// @brief Create ObjectFile from path.
292  static ObjectFile *createObjectFile(StringRef ObjectPath);
293  static ObjectFile *createObjectFile(MemoryBuffer *Object);
294
295  static inline bool classof(const Binary *v) {
296    return v->getType() >= isObject &&
297           v->getType() < lastObject;
298  }
299  static inline bool classof(const ObjectFile *v) { return true; }
300
301public:
302  static ObjectFile *createCOFFObjectFile(MemoryBuffer *Object);
303  static ObjectFile *createELFObjectFile(MemoryBuffer *Object);
304  static ObjectFile *createMachOObjectFile(MemoryBuffer *Object);
305};
306
307// Inline function definitions.
308inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner)
309  : SymbolPimpl(SymbolP)
310  , OwningObject(Owner) {}
311
312inline bool SymbolRef::operator==(const SymbolRef &Other) const {
313  return SymbolPimpl == Other.SymbolPimpl;
314}
315
316inline error_code SymbolRef::getNext(SymbolRef &Result) const {
317  return OwningObject->getSymbolNext(SymbolPimpl, Result);
318}
319
320inline error_code SymbolRef::getName(StringRef &Result) const {
321  return OwningObject->getSymbolName(SymbolPimpl, Result);
322}
323
324inline error_code SymbolRef::getAddress(uint64_t &Result) const {
325  return OwningObject->getSymbolAddress(SymbolPimpl, Result);
326}
327
328inline error_code SymbolRef::getOffset(uint64_t &Result) const {
329  return OwningObject->getSymbolOffset(SymbolPimpl, Result);
330}
331
332inline error_code SymbolRef::getSize(uint64_t &Result) const {
333  return OwningObject->getSymbolSize(SymbolPimpl, Result);
334}
335
336inline error_code SymbolRef::getNMTypeChar(char &Result) const {
337  return OwningObject->getSymbolNMTypeChar(SymbolPimpl, Result);
338}
339
340inline error_code SymbolRef::isInternal(bool &Result) const {
341  return OwningObject->isSymbolInternal(SymbolPimpl, Result);
342}
343
344inline error_code SymbolRef::isGlobal(bool &Result) const {
345  return OwningObject->isSymbolGlobal(SymbolPimpl, Result);
346}
347
348inline error_code SymbolRef::getType(SymbolRef::Type &Result) const {
349  return OwningObject->getSymbolType(SymbolPimpl, Result);
350}
351
352inline DataRefImpl SymbolRef::getRawDataRefImpl() const {
353  return SymbolPimpl;
354}
355
356
357/// SectionRef
358inline SectionRef::SectionRef(DataRefImpl SectionP,
359                              const ObjectFile *Owner)
360  : SectionPimpl(SectionP)
361  , OwningObject(Owner) {}
362
363inline bool SectionRef::operator==(const SectionRef &Other) const {
364  return SectionPimpl == Other.SectionPimpl;
365}
366
367inline error_code SectionRef::getNext(SectionRef &Result) const {
368  return OwningObject->getSectionNext(SectionPimpl, Result);
369}
370
371inline error_code SectionRef::getName(StringRef &Result) const {
372  return OwningObject->getSectionName(SectionPimpl, Result);
373}
374
375inline error_code SectionRef::getAddress(uint64_t &Result) const {
376  return OwningObject->getSectionAddress(SectionPimpl, Result);
377}
378
379inline error_code SectionRef::getSize(uint64_t &Result) const {
380  return OwningObject->getSectionSize(SectionPimpl, Result);
381}
382
383inline error_code SectionRef::getContents(StringRef &Result) const {
384  return OwningObject->getSectionContents(SectionPimpl, Result);
385}
386
387inline error_code SectionRef::getAlignment(uint64_t &Result) const {
388  return OwningObject->getSectionAlignment(SectionPimpl, Result);
389}
390
391inline error_code SectionRef::isText(bool &Result) const {
392  return OwningObject->isSectionText(SectionPimpl, Result);
393}
394
395inline error_code SectionRef::isData(bool &Result) const {
396  return OwningObject->isSectionData(SectionPimpl, Result);
397}
398
399inline error_code SectionRef::isBSS(bool &Result) const {
400  return OwningObject->isSectionBSS(SectionPimpl, Result);
401}
402
403inline error_code SectionRef::containsSymbol(SymbolRef S, bool &Result) const {
404  return OwningObject->sectionContainsSymbol(SectionPimpl, S.SymbolPimpl,
405                                             Result);
406}
407
408inline relocation_iterator SectionRef::begin_relocations() const {
409  return OwningObject->getSectionRelBegin(SectionPimpl);
410}
411
412inline relocation_iterator SectionRef::end_relocations() const {
413  return OwningObject->getSectionRelEnd(SectionPimpl);
414}
415
416
417/// RelocationRef
418inline RelocationRef::RelocationRef(DataRefImpl RelocationP,
419                              const ObjectFile *Owner)
420  : RelocationPimpl(RelocationP)
421  , OwningObject(Owner) {}
422
423inline bool RelocationRef::operator==(const RelocationRef &Other) const {
424  return RelocationPimpl == Other.RelocationPimpl;
425}
426
427inline error_code RelocationRef::getNext(RelocationRef &Result) const {
428  return OwningObject->getRelocationNext(RelocationPimpl, Result);
429}
430
431inline error_code RelocationRef::getAddress(uint64_t &Result) const {
432  return OwningObject->getRelocationAddress(RelocationPimpl, Result);
433}
434
435inline error_code RelocationRef::getSymbol(SymbolRef &Result) const {
436  return OwningObject->getRelocationSymbol(RelocationPimpl, Result);
437}
438
439inline error_code RelocationRef::getType(uint32_t &Result) const {
440  return OwningObject->getRelocationType(RelocationPimpl, Result);
441}
442
443inline error_code RelocationRef::getTypeName(SmallVectorImpl<char> &Result)
444  const {
445  return OwningObject->getRelocationTypeName(RelocationPimpl, Result);
446}
447
448inline error_code RelocationRef::getAdditionalInfo(int64_t &Result) const {
449  return OwningObject->getRelocationAdditionalInfo(RelocationPimpl, Result);
450}
451
452inline error_code RelocationRef::getValueString(SmallVectorImpl<char> &Result)
453  const {
454  return OwningObject->getRelocationValueString(RelocationPimpl, Result);
455}
456
457} // end namespace object
458} // end namespace llvm
459
460#endif
461