ResolveInfo.h revision 5460a1f25d9ddecb5c70667267d66d51af177a99 
1//===- ResolveInfo.h ------------------------------------------------------===//
2//
3//                     The MCLinker Project
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9#ifndef MCLD_RESOLVE_INFO_H
10#define MCLD_RESOLVE_INFO_H
11#ifdef ENABLE_UNITTEST
12#include <gtest.h>
13#endif
14
15#include <llvm/Support/DataTypes.h>
16#include <llvm/ADT/StringRef.h>
17
18namespace mcld
19{
20
21class LDSymbol;
22
23/** \class ResolveInfo
24 *  \brief ResolveInfo records the information about how to resolve a symbol.
25 *
26 *  A symbol must have some `attributes':
27 *  - Desc - Defined, Reference, Common or Indirect
28 *  - Binding - Global, Local, Weak
29 *  - IsDyn - appear in dynamic objects or regular objects
30 *  - Type - what the symbol points to
31 *  - Size  - the size of the symbol point to
32 *  - Value - the pointer to another LDSymbol
33 *  In order to save the memory and speed up the performance, MCLinker uses
34 *  a bit field to store all attributes.
35 *
36 *  The maximum string length is (2^16 - 1)
37 */
38class ResolveInfo
39{
40friend class ResolveInfoFactory;
41friend class MCLinker;
42public:
43  typedef uint64_t SizeType;
44
45  /** \enum Type
46   *  \brief What the symbol stand for
47   *
48   *  It is like ELF32_ST_TYPE
49   *  MachO does not need this, and can not jump between Thumb and ARM code.
50   */
51  enum Type {
52    NoType        = 0,
53    Object        = 1,
54    Function      = 2,
55    Section       = 3,
56    File          = 4,
57    CommonBlock   = 5,
58    ThreadLocal    = 6,
59    LoProc        = 13,
60    HiProc        = 15
61  };
62
63  /** \enum Desc
64   *  \brief Description of the symbols.
65   *
66   *   Follow the naming in MachO. Like MachO nlist::n_desc
67   *   In ELF, is a part of st_shndx
68   */
69  enum Desc {
70    Undefined    = 0,
71    Define       = 1,
72    Common       = 2,
73    Indirect     = 3,
74    NoneDesc
75  };
76
77  enum Binding {
78    Global       = 0,
79    Weak         = 1,
80    Local        = 2,
81    Absolute     = 3,
82    NoneBinding
83  };
84
85  enum Visibility {
86    Default      = 0,
87    Internal     = 1,
88    Hidden       = 2,
89    Protected    = 3
90  };
91
92  // -----  For HashTable  ----- //
93  typedef llvm::StringRef key_type;
94
95public:
96  // -----  modifiers  ----- //
97  /// setRegular - set the source of the file is a regular object
98  void setRegular();
99
100  /// setDynamic - set the source of the file is a dynamic object
101  void setDynamic();
102
103  /// setSource - set the source of the file
104  /// @param pIsDyn is the source from a dynamic object?
105  void setSource(bool pIsDyn);
106
107  void setType(uint32_t pType);
108
109  void setDesc(uint32_t pDesc);
110
111  void setBinding(uint32_t pBinding);
112
113  void setOther(uint32_t pOther);
114
115  void setVisibility(Visibility pVisibility);
116
117  void setIsSymbol(bool pIsSymbol);
118
119  void setReserved(uint32_t pReserved);
120
121  void setSize(SizeType pSize)
122  { m_Size = pSize; }
123
124  void override(const ResolveInfo& pForm);
125
126  void overrideAttributes(const ResolveInfo& pFrom);
127
128  void overrideVisibility(const ResolveInfo& pFrom);
129
130  void setSymPtr(const LDSymbol* pSymPtr)
131  { m_Ptr.sym_ptr = const_cast<LDSymbol*>(pSymPtr); }
132
133  void setLink(const ResolveInfo* pTarget) {
134    m_Ptr.info_ptr = const_cast<ResolveInfo*>(pTarget);
135    m_BitField |= indirect_flag;
136  }
137
138
139  // -----  observers  ----- //
140  bool isSymbol() const;
141
142  bool isString() const;
143
144  bool isGlobal() const;
145
146  bool isWeak() const;
147
148  bool isLocal() const;
149
150  bool isAbsolute() const;
151
152  bool isDefine() const;
153
154  bool isUndef() const;
155
156  bool isDyn() const;
157
158  bool isCommon() const;
159
160  bool isIndirect() const;
161
162  uint32_t type() const;
163
164  uint32_t desc() const;
165
166  uint32_t binding() const;
167
168  uint32_t reserved() const;
169
170  uint8_t other() const
171  { return (uint8_t)visibility(); }
172
173  Visibility visibility() const;
174
175  LDSymbol* outSymbol()
176  { return m_Ptr.sym_ptr; }
177
178  const LDSymbol* outSymbol() const
179  { return m_Ptr.sym_ptr; }
180
181  ResolveInfo* link()
182  { return m_Ptr.info_ptr; }
183
184  const ResolveInfo* link() const
185  { return m_Ptr.info_ptr; }
186
187  SizeType size() const
188  { return m_Size; }
189
190  const char* name() const
191  { return m_Name; }
192
193  unsigned int nameSize() const
194  { return (m_BitField >> NAME_LENGTH_OFFSET); }
195
196  uint32_t info() const
197  { return (m_BitField & INFO_MASK); }
198
199  uint32_t bitfield() const
200  { return m_BitField; }
201
202  // -----  For HashTable  ----- //
203  bool compare(const key_type& pKey);
204
205private:
206  static const uint32_t GLOBAL_OFFSET      = 0;
207  static const uint32_t GLOBAL_MASK        = 1;
208
209  static const uint32_t DYN_OFFSET         = 1;
210  static const uint32_t DYN_MASK           = 1   << DYN_OFFSET;
211
212  static const uint32_t DESC_OFFSET        = 2;
213  static const uint32_t DESC_MASK          = 0x3 << DESC_OFFSET;
214
215  static const uint32_t LOCAL_OFFSET       = 4;
216  static const uint32_t LOCAL_MASK         = 1   << LOCAL_OFFSET;
217
218  static const uint32_t BINDING_MASK       = GLOBAL_MASK | LOCAL_MASK;
219
220  static const uint32_t VISIBILITY_OFFSET  = 5;
221  static const uint32_t VISIBILITY_MASK    = 0x3 << VISIBILITY_OFFSET;
222
223  static const uint32_t TYPE_OFFSET        = 7;
224  static const uint32_t TYPE_MASK          = 0xF << TYPE_OFFSET;
225
226  static const uint32_t SYMBOL_OFFSET      = 11;
227  static const uint32_t SYMBOL_MASK        = 1   << SYMBOL_OFFSET;
228
229  static const uint32_t RESERVED_OFFSET    = 12;
230  static const uint32_t RESERVED_MASK      = 0xF << RESERVED_OFFSET;
231  static const uint32_t NAME_LENGTH_OFFSET = 16;
232  static const uint32_t INFO_MASK          = 0xF;
233  static const uint32_t RESOLVE_MASK       = 0xFFFF;
234
235  union SymOrInfo {
236    LDSymbol*    sym_ptr;
237    ResolveInfo* info_ptr;
238  };
239
240public:
241  static const uint32_t global_flag    = 0        << GLOBAL_OFFSET;
242  static const uint32_t weak_flag      = 1        << GLOBAL_OFFSET;
243  static const uint32_t regular_flag   = 0        << DYN_OFFSET;
244  static const uint32_t dynamic_flag   = 1        << DYN_OFFSET;
245  static const uint32_t undefine_flag  = 0        << DESC_OFFSET;
246  static const uint32_t define_flag    = 1        << DESC_OFFSET;
247  static const uint32_t common_flag    = 2        << DESC_OFFSET;
248  static const uint32_t indirect_flag  = 3        << DESC_OFFSET;
249  static const uint32_t local_flag     = 1        << LOCAL_OFFSET;
250  static const uint32_t absolute_flag  = BINDING_MASK;
251  static const uint32_t object_flag    = Object   << TYPE_OFFSET;
252  static const uint32_t function_flag  = Function << TYPE_OFFSET;
253  static const uint32_t section_flag   = Section  << TYPE_OFFSET;
254  static const uint32_t file_flag      = File     << TYPE_OFFSET;
255  static const uint32_t string_flag    = 0        << SYMBOL_OFFSET;
256  static const uint32_t symbol_flag    = 1        << SYMBOL_OFFSET;
257
258private:
259  ResolveInfo();
260  ResolveInfo(const ResolveInfo& pCopy);
261  ResolveInfo& operator=(const ResolveInfo& pCopy);
262  ~ResolveInfo();
263
264private:
265  SizeType m_Size;
266  SymOrInfo m_Ptr;
267
268  /** m_BitField
269   *  31     ...    16 15    12 11     10..7 6      ..    5 4     3   2   1   0
270   * |length of m_Name|reserved|Symbol|Type |ELF visibility|Local|Com|Def|Dyn|Weak|
271   */
272  uint32_t m_BitField;
273  char m_Name[0];
274};
275
276} // namespace of mcld
277
278#endif
279
280