ResolveInfo.h revision f33f6de54db174aa679a4b6d1e040d37e95541c0 
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_LD_RESOLVEINFO_H
10#define MCLD_LD_RESOLVEINFO_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
20class LDSymbol;
21class LinkerConfig;
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 refers 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, FragmentLinker 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 FragmentLinker;
41friend class IRBuilder;
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    IndirectFunc  = 10,
60    LoProc        = 13,
61    HiProc        = 15
62  };
63
64  /** \enum Desc
65   *  \brief Description of the symbols.
66   *
67   *   Follow the naming in MachO. Like MachO nlist::n_desc
68   *   In ELF, is a part of st_shndx
69   */
70  enum Desc {
71    Undefined    = 0,
72    Define       = 1,
73    Common       = 2,
74    Indirect     = 3,
75    NoneDesc
76  };
77
78  enum Binding {
79    Global       = 0,
80    Weak         = 1,
81    Local        = 2,
82    Absolute     = 3,
83    NoneBinding
84  };
85
86  enum Visibility {
87    Default      = 0,
88    Internal     = 1,
89    Hidden       = 2,
90    Protected    = 3
91  };
92
93  // -----  For HashTable  ----- //
94  typedef llvm::StringRef key_type;
95
96public:
97  // -----  factory method  ----- //
98  static ResolveInfo* Create(const key_type& pKey);
99
100  static void Destroy(ResolveInfo*& pInfo);
101
102  static ResolveInfo* Null();
103
104  // -----  modifiers  ----- //
105  /// setRegular - set the source of the file is a regular object
106  void setRegular();
107
108  /// setDynamic - set the source of the file is a dynamic object
109  void setDynamic();
110
111  /// setSource - set the source of the file
112  /// @param pIsDyn is the source from a dynamic object?
113  void setSource(bool pIsDyn);
114
115  void setType(uint32_t pType);
116
117  void setDesc(uint32_t pDesc);
118
119  void setBinding(uint32_t pBinding);
120
121  void setOther(uint32_t pOther);
122
123  void setVisibility(Visibility pVisibility);
124
125  void setIsSymbol(bool pIsSymbol);
126
127  void setReserved(uint32_t pReserved);
128
129  void setSize(SizeType pSize)
130  { m_Size = pSize; }
131
132  void override(const ResolveInfo& pForm);
133
134  void overrideAttributes(const ResolveInfo& pFrom);
135
136  void overrideVisibility(const ResolveInfo& pFrom);
137
138  void setSymPtr(const LDSymbol* pSymPtr)
139  { m_Ptr.sym_ptr = const_cast<LDSymbol*>(pSymPtr); }
140
141  void setLink(const ResolveInfo* pTarget) {
142    m_Ptr.info_ptr = const_cast<ResolveInfo*>(pTarget);
143    m_BitField |= indirect_flag;
144  }
145
146  /// setInDyn - set if the symbol has been seen in the dynamic objects. Once
147  /// InDyn set, then it won't be set back to false
148  void setInDyn();
149
150  // -----  observers  ----- //
151  bool isNull() const;
152
153  bool isSymbol() const;
154
155  bool isString() const;
156
157  bool isGlobal() const;
158
159  bool isWeak() const;
160
161  bool isLocal() const;
162
163  bool isAbsolute() const;
164
165  bool isDefine() const;
166
167  bool isUndef() const;
168
169  bool isDyn() const;
170
171  bool isCommon() const;
172
173  bool isIndirect() const;
174
175  bool isInDyn() const;
176
177  uint32_t type() const;
178
179  uint32_t desc() const;
180
181  uint32_t binding() const;
182
183  uint32_t reserved() const;
184
185  uint8_t other() const
186  { return (uint8_t)visibility(); }
187
188  Visibility visibility() const;
189
190  LDSymbol* outSymbol()
191  { return m_Ptr.sym_ptr; }
192
193  const LDSymbol* outSymbol() const
194  { return m_Ptr.sym_ptr; }
195
196  ResolveInfo* link()
197  { return m_Ptr.info_ptr; }
198
199  const ResolveInfo* link() const
200  { return m_Ptr.info_ptr; }
201
202  SizeType size() const
203  { return m_Size; }
204
205  const char* name() const
206  { return m_Name; }
207
208  unsigned int nameSize() const
209  { return (m_BitField >> NAME_LENGTH_OFFSET); }
210
211  uint32_t info() const
212  { return (m_BitField & INFO_MASK); }
213
214  uint32_t bitfield() const
215  { return m_BitField; }
216
217  // shouldForceLocal - check if this symbol should be forced to local
218  bool shouldForceLocal(const LinkerConfig& pConfig);
219
220  // -----  For HashTable  ----- //
221  bool compare(const key_type& pKey);
222
223private:
224  static const uint32_t GLOBAL_OFFSET      = 0;
225  static const uint32_t GLOBAL_MASK        = 1;
226
227  static const uint32_t DYN_OFFSET         = 1;
228  static const uint32_t DYN_MASK           = 1   << DYN_OFFSET;
229
230  static const uint32_t DESC_OFFSET        = 2;
231  static const uint32_t DESC_MASK          = 0x3 << DESC_OFFSET;
232
233  static const uint32_t LOCAL_OFFSET       = 4;
234  static const uint32_t LOCAL_MASK         = 1   << LOCAL_OFFSET;
235
236  static const uint32_t BINDING_MASK       = GLOBAL_MASK | LOCAL_MASK;
237
238  static const uint32_t VISIBILITY_OFFSET  = 5;
239  static const uint32_t VISIBILITY_MASK    = 0x3 << VISIBILITY_OFFSET;
240
241  static const uint32_t TYPE_OFFSET        = 7;
242  static const uint32_t TYPE_MASK          = 0xF << TYPE_OFFSET;
243
244  static const uint32_t SYMBOL_OFFSET      = 11;
245  static const uint32_t SYMBOL_MASK        = 1   << SYMBOL_OFFSET;
246
247  static const uint32_t RESERVED_OFFSET    = 12;
248  static const uint32_t RESERVED_MASK      = 0xF << RESERVED_OFFSET;
249
250  static const uint32_t IN_DYN_OFFSET      = 16;
251  static const uint32_t IN_DYN_MASK        = 1   << IN_DYN_OFFSET;
252
253  static const uint32_t NAME_LENGTH_OFFSET = 17;
254  static const uint32_t INFO_MASK          = 0xF;
255  static const uint32_t RESOLVE_MASK       = 0xFFFF;
256
257  union SymOrInfo {
258    LDSymbol*    sym_ptr;
259    ResolveInfo* info_ptr;
260  };
261
262public:
263  static const uint32_t global_flag    = 0        << GLOBAL_OFFSET;
264  static const uint32_t weak_flag      = 1        << GLOBAL_OFFSET;
265  static const uint32_t regular_flag   = 0        << DYN_OFFSET;
266  static const uint32_t dynamic_flag   = 1        << DYN_OFFSET;
267  static const uint32_t undefine_flag  = 0        << DESC_OFFSET;
268  static const uint32_t define_flag    = 1        << DESC_OFFSET;
269  static const uint32_t common_flag    = 2        << DESC_OFFSET;
270  static const uint32_t indirect_flag  = 3        << DESC_OFFSET;
271  static const uint32_t local_flag     = 1        << LOCAL_OFFSET;
272  static const uint32_t absolute_flag  = BINDING_MASK;
273  static const uint32_t object_flag    = Object   << TYPE_OFFSET;
274  static const uint32_t function_flag  = Function << TYPE_OFFSET;
275  static const uint32_t section_flag   = Section  << TYPE_OFFSET;
276  static const uint32_t file_flag      = File     << TYPE_OFFSET;
277  static const uint32_t string_flag    = 0        << SYMBOL_OFFSET;
278  static const uint32_t symbol_flag    = 1        << SYMBOL_OFFSET;
279  static const uint32_t indyn_flag     = 1        << IN_DYN_OFFSET;
280
281private:
282  ResolveInfo();
283  ResolveInfo(const ResolveInfo& pCopy);
284  ResolveInfo& operator=(const ResolveInfo& pCopy);
285  ~ResolveInfo();
286
287private:
288  SizeType m_Size;
289  SymOrInfo m_Ptr;
290
291  /** m_BitField
292   *  31     ...    17 16    15    12 11     10..7 6      ..    5 4     3   2   1   0
293   * |length of m_Name|InDyn|reserved|Symbol|Type |ELF visibility|Local|Com|Def|Dyn|Weak|
294   */
295  uint32_t m_BitField;
296  char m_Name[];
297};
298
299} // namespace of mcld
300
301#endif
302
303