ObjectFile.h revision 739b65bf85cf7221b8a615e83dee11ec729e2649 
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    uint32_t a, b;
32  } d;
33  uintptr_t p;
34};
35
36static bool operator ==(const DataRefImpl &a, const DataRefImpl &b) {
37  // Check bitwise identical. This is the only legal way to compare a union w/o
38  // knowing which member is in use.
39  return std::memcmp(&a, &b, sizeof(DataRefImpl)) == 0;
40}
41
42class RelocationRef {
43  DataRefImpl RelocationPimpl;
44  const ObjectFile *OwningObject;
45
46public:
47  RelocationRef() : OwningObject(NULL) {
48    std::memset(&RelocationPimpl, 0, sizeof(RelocationPimpl));
49  }
50
51  RelocationRef(DataRefImpl RelocationP, const ObjectFile *Owner);
52
53  bool operator==(const RelocationRef &Other) const;
54
55  error_code getNext(RelocationRef &Result);
56};
57
58/// SymbolRef - This is a value type class that represents a single symbol in
59/// the list of symbols in the object file.
60class SymbolRef {
61  friend class SectionRef;
62  DataRefImpl SymbolPimpl;
63  const ObjectFile *OwningObject;
64
65public:
66  SymbolRef() : OwningObject(NULL) {
67    std::memset(&SymbolPimpl, 0, sizeof(SymbolPimpl));
68  }
69
70  SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner);
71
72  bool operator==(const SymbolRef &Other) const;
73
74  error_code getNext(SymbolRef &Result) const;
75
76  error_code getName(StringRef &Result) const;
77  error_code getAddress(uint64_t &Result) const;
78  error_code getSize(uint64_t &Result) const;
79
80  /// Returns the ascii char that should be displayed in a symbol table dump via
81  /// nm for this symbol.
82  error_code getNMTypeChar(char &Result) const;
83
84  /// Returns true for symbols that are internal to the object file format such
85  /// as section symbols.
86  error_code isInternal(bool &Result) const;
87};
88
89/// SectionRef - This is a value type class that represents a single section in
90/// the list of sections in the object file.
91class SectionRef {
92  friend class SymbolRef;
93  DataRefImpl SectionPimpl;
94  const ObjectFile *OwningObject;
95
96public:
97  SectionRef() : OwningObject(NULL) {
98    std::memset(&SectionPimpl, 0, sizeof(SectionPimpl));
99  }
100
101  SectionRef(DataRefImpl SectionP, const ObjectFile *Owner);
102
103  bool operator==(const SectionRef &Other) const;
104
105  error_code getNext(SectionRef &Result) const;
106
107  error_code getName(StringRef &Result) const;
108  error_code getAddress(uint64_t &Result) const;
109  error_code getSize(uint64_t &Result) const;
110  error_code getContents(StringRef &Result) const;
111
112  // FIXME: Move to the normalization layer when it's created.
113  error_code isText(bool &Result) const;
114
115  error_code containsSymbol(SymbolRef S, bool &Result) const;
116};
117
118const uint64_t UnknownAddressOrSize = ~0ULL;
119
120/// ObjectFile - This class is the base class for all object file types.
121/// Concrete instances of this object are created by createObjectFile, which
122/// figure out which type to create.
123class ObjectFile : public Binary {
124private:
125  ObjectFile(); // = delete
126  ObjectFile(const ObjectFile &other); // = delete
127
128protected:
129  ObjectFile(unsigned int Type, MemoryBuffer *source, error_code &ec);
130
131  const uint8_t *base() const {
132    return reinterpret_cast<const uint8_t *>(Data->getBufferStart());
133  }
134
135  // These functions are for SymbolRef to call internally. The main goal of
136  // this is to allow SymbolRef::SymbolPimpl to point directly to the symbol
137  // entry in the memory mapped object file. SymbolPimpl cannot contain any
138  // virtual functions because then it could not point into the memory mapped
139  // file.
140  //
141  // Implementations assume that the DataRefImpl is valid and has not been
142  // modified externally. It's UB otherwise.
143  friend class SymbolRef;
144  virtual error_code getSymbolNext(DataRefImpl Symb, SymbolRef &Res) const = 0;
145  virtual error_code getSymbolName(DataRefImpl Symb, StringRef &Res) const = 0;
146  virtual error_code getSymbolAddress(DataRefImpl Symb, uint64_t &Res) const =0;
147  virtual error_code getSymbolSize(DataRefImpl Symb, uint64_t &Res) const = 0;
148  virtual error_code getSymbolNMTypeChar(DataRefImpl Symb, char &Res) const = 0;
149  virtual error_code isSymbolInternal(DataRefImpl Symb, bool &Res) const = 0;
150
151  // Same as above for SectionRef.
152  friend class SectionRef;
153  virtual error_code getSectionNext(DataRefImpl Sec, SectionRef &Res) const = 0;
154  virtual error_code getSectionName(DataRefImpl Sec, StringRef &Res) const = 0;
155  virtual error_code getSectionAddress(DataRefImpl Sec, uint64_t &Res) const =0;
156  virtual error_code getSectionSize(DataRefImpl Sec, uint64_t &Res) const = 0;
157  virtual error_code getSectionContents(DataRefImpl Sec, StringRef &Res)const=0;
158  virtual error_code isSectionText(DataRefImpl Sec, bool &Res) const = 0;
159  virtual error_code sectionContainsSymbol(DataRefImpl Sec, DataRefImpl Symb,
160                                           bool &Result) const = 0;
161
162
163public:
164  template<class content_type>
165  class content_iterator {
166    content_type Current;
167  public:
168    content_iterator(content_type symb)
169      : Current(symb) {}
170
171    const content_type* operator->() const {
172      return &Current;
173    }
174
175    const content_type &operator*() const {
176      return Current;
177    }
178
179    bool operator==(const content_iterator &other) const {
180      return Current == other.Current;
181    }
182
183    bool operator!=(const content_iterator &other) const {
184      return !(*this == other);
185    }
186
187    content_iterator& increment(error_code &err) {
188      content_type next;
189      if (error_code ec = Current.getNext(next))
190        err = ec;
191      else
192        Current = next;
193      return *this;
194    }
195  };
196
197  typedef content_iterator<SymbolRef> symbol_iterator;
198  typedef content_iterator<SectionRef> section_iterator;
199
200  virtual symbol_iterator begin_symbols() const = 0;
201  virtual symbol_iterator end_symbols() const = 0;
202
203  virtual section_iterator begin_sections() const = 0;
204  virtual section_iterator end_sections() const = 0;
205
206  /// @brief The number of bytes used to represent an address in this object
207  ///        file format.
208  virtual uint8_t getBytesInAddress() const = 0;
209
210  virtual StringRef getFileFormatName() const = 0;
211  virtual /* Triple::ArchType */ unsigned getArch() const = 0;
212
213  /// @returns Pointer to ObjectFile subclass to handle this type of object.
214  /// @param ObjectPath The path to the object file. ObjectPath.isObject must
215  ///        return true.
216  /// @brief Create ObjectFile from path.
217  static ObjectFile *createObjectFile(StringRef ObjectPath);
218  static ObjectFile *createObjectFile(MemoryBuffer *Object);
219
220  static inline bool classof(const Binary *v) {
221    return v->getType() >= isObject &&
222           v->getType() < lastObject;
223  }
224  static inline bool classof(const ObjectFile *v) { return true; }
225
226public:
227  static ObjectFile *createCOFFObjectFile(MemoryBuffer *Object);
228  static ObjectFile *createELFObjectFile(MemoryBuffer *Object);
229  static ObjectFile *createMachOObjectFile(MemoryBuffer *Object);
230};
231
232// Inline function definitions.
233inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner)
234  : SymbolPimpl(SymbolP)
235  , OwningObject(Owner) {}
236
237inline bool SymbolRef::operator==(const SymbolRef &Other) const {
238  return SymbolPimpl == Other.SymbolPimpl;
239}
240
241inline error_code SymbolRef::getNext(SymbolRef &Result) const {
242  return OwningObject->getSymbolNext(SymbolPimpl, Result);
243}
244
245inline error_code SymbolRef::getName(StringRef &Result) const {
246  return OwningObject->getSymbolName(SymbolPimpl, Result);
247}
248
249inline error_code SymbolRef::getAddress(uint64_t &Result) const {
250  return OwningObject->getSymbolAddress(SymbolPimpl, Result);
251}
252
253inline error_code SymbolRef::getSize(uint64_t &Result) const {
254  return OwningObject->getSymbolSize(SymbolPimpl, Result);
255}
256
257inline error_code SymbolRef::getNMTypeChar(char &Result) const {
258  return OwningObject->getSymbolNMTypeChar(SymbolPimpl, Result);
259}
260
261inline error_code SymbolRef::isInternal(bool &Result) const {
262  return OwningObject->isSymbolInternal(SymbolPimpl, Result);
263}
264
265
266/// SectionRef
267inline SectionRef::SectionRef(DataRefImpl SectionP,
268                              const ObjectFile *Owner)
269  : SectionPimpl(SectionP)
270  , OwningObject(Owner) {}
271
272inline bool SectionRef::operator==(const SectionRef &Other) const {
273  return SectionPimpl == Other.SectionPimpl;
274}
275
276inline error_code SectionRef::getNext(SectionRef &Result) const {
277  return OwningObject->getSectionNext(SectionPimpl, Result);
278}
279
280inline error_code SectionRef::getName(StringRef &Result) const {
281  return OwningObject->getSectionName(SectionPimpl, Result);
282}
283
284inline error_code SectionRef::getAddress(uint64_t &Result) const {
285  return OwningObject->getSectionAddress(SectionPimpl, Result);
286}
287
288inline error_code SectionRef::getSize(uint64_t &Result) const {
289  return OwningObject->getSectionSize(SectionPimpl, Result);
290}
291
292inline error_code SectionRef::getContents(StringRef &Result) const {
293  return OwningObject->getSectionContents(SectionPimpl, Result);
294}
295
296inline error_code SectionRef::isText(bool &Result) const {
297  return OwningObject->isSectionText(SectionPimpl, Result);
298}
299
300inline error_code SectionRef::containsSymbol(SymbolRef S, bool &Result) const {
301  return OwningObject->sectionContainsSymbol(SectionPimpl, S.SymbolPimpl,
302                                             Result);
303}
304
305} // end namespace object
306} // end namespace llvm
307
308#endif
309