aboutsummaryrefslogtreecommitdiff
path: root/gcc/hash-traits.h
blob: 450354ae1d706a0688b27e4de620b2a5d568eb6f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
/* Traits for hashable types.
   Copyright (C) 2014-2015 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#ifndef hash_traits_h
#define hash_traits_h

/* Helpful type for removing with free.  */

template <typename Type>
struct typed_free_remove
{
  static inline void remove (Type *p);
};


/* Remove with free.  */

template <typename Type>
inline void
typed_free_remove <Type>::remove (Type *p)
{
  free (p);
}


/* Helpful type for a no-op remove.  */

template <typename Type>
struct typed_noop_remove
{
  static inline void remove (Type &);
};


/* Remove doing nothing.  */

template <typename Type>
inline void
typed_noop_remove <Type>::remove (Type &)
{
}


/* Hasher for integer type Type in which Empty is a spare value that can be
   used to mark empty slots.  If Deleted != Empty then Deleted is another
   spare value that can be used for deleted slots; if Deleted == Empty then
   hash table entries cannot be deleted.  */

template <typename Type, Type Empty, Type Deleted = Empty>
struct int_hash : typed_noop_remove <Type>
{
  typedef Type value_type;
  typedef Type compare_type;

  static inline hashval_t hash (value_type);
  static inline bool equal (value_type existing, value_type candidate);
  static inline void mark_deleted (Type &);
  static inline void mark_empty (Type &);
  static inline bool is_deleted (Type);
  static inline bool is_empty (Type);
};

template <typename Type, Type Empty, Type Deleted>
inline hashval_t
int_hash <Type, Empty, Deleted>::hash (value_type x)
{
  return x;
}

template <typename Type, Type Empty, Type Deleted>
inline bool
int_hash <Type, Empty, Deleted>::equal (value_type x, value_type y)
{
  return x == y;
}

template <typename Type, Type Empty, Type Deleted>
inline void
int_hash <Type, Empty, Deleted>::mark_deleted (Type &x)
{
  gcc_assert (Empty != Deleted);
  x = Deleted;
}

template <typename Type, Type Empty, Type Deleted>
inline void
int_hash <Type, Empty, Deleted>::mark_empty (Type &x)
{
  x = Empty;
}

template <typename Type, Type Empty, Type Deleted>
inline bool
int_hash <Type, Empty, Deleted>::is_deleted (Type x)
{
  return Empty != Deleted && x == Deleted;
}

template <typename Type, Type Empty, Type Deleted>
inline bool
int_hash <Type, Empty, Deleted>::is_empty (Type x)
{
  return x == Empty;
}

/* Pointer hasher based on pointer equality.  Other types of pointer hash
   can inherit this and override the hash and equal functions with some
   other form of equality (such as string equality).  */

template <typename Type>
struct pointer_hash
{
  typedef Type *value_type;
  typedef Type *compare_type;

  static inline hashval_t hash (const value_type &);
  static inline bool equal (const value_type &existing,
			    const compare_type &candidate);
  static inline void mark_deleted (Type *&);
  static inline void mark_empty (Type *&);
  static inline bool is_deleted (Type *);
  static inline bool is_empty (Type *);
};

template <typename Type>
inline hashval_t
pointer_hash <Type>::hash (const value_type &candidate)
{
  /* This is a really poor hash function, but it is what the current code uses,
     so I am reusing it to avoid an additional axis in testing.  */
  return (hashval_t) ((intptr_t)candidate >> 3);
}

template <typename Type>
inline bool
pointer_hash <Type>::equal (const value_type &existing,
			   const compare_type &candidate)
{
  return existing == candidate;
}

template <typename Type>
inline void
pointer_hash <Type>::mark_deleted (Type *&e)
{
  e = reinterpret_cast<Type *> (1);
}

template <typename Type>
inline void
pointer_hash <Type>::mark_empty (Type *&e)
{
  e = NULL;
}

template <typename Type>
inline bool
pointer_hash <Type>::is_deleted (Type *e)
{
  return e == reinterpret_cast<Type *> (1);
}

template <typename Type>
inline bool
pointer_hash <Type>::is_empty (Type *e)
{
  return e == NULL;
}

/* Hasher for "const char *" strings, using string rather than pointer
   equality.  */

struct string_hash : pointer_hash <const char>
{
  static inline hashval_t hash (const char *);
  static inline bool equal (const char *, const char *);
};

inline hashval_t
string_hash::hash (const char *id)
{
  return htab_hash_string (id);
}

inline bool
string_hash::equal (const char *id1, const char *id2)
{
  return strcmp (id1, id2) == 0;
}

/* Remover and marker for entries in gc memory.  */

template<typename T>
struct ggc_remove
{
  static void remove (T &) {}

  static void
  ggc_mx (T &p)
  {
    extern void gt_ggc_mx (T &);
    gt_ggc_mx (p);
  }

  static void
  pch_nx (T &p)
  {
    extern void gt_pch_nx (T &);
    gt_pch_nx (p);
  }

  static void
  pch_nx (T &p, gt_pointer_operator op, void *cookie)
  {
    op (&p, cookie);
  }
};

/* Remover and marker for "cache" entries in gc memory.  These entries can
   be deleted if there are no non-cache references to the data.  */

template<typename T>
struct ggc_cache_remove : ggc_remove<T>
{
  /* Entries are weakly held because this is for caches.  */
  static void ggc_mx (T &) {}

  static int
  keep_cache_entry (T &e)
  {
    return ggc_marked_p (e) ? -1 : 0;
  }
};

/* Traits for pointer elements that should not be freed when an element
   is deleted.  */

template <typename T>
struct nofree_ptr_hash : pointer_hash <T>, typed_noop_remove <T *> {};

/* Traits for pointer elements that should be freed via free() when an
   element is deleted.  */

template <typename T>
struct free_ptr_hash : pointer_hash <T>, typed_free_remove <T> {};

/* Traits for elements that point to gc memory.  The pointed-to data
   must be kept across collections.  */

template <typename T>
struct ggc_ptr_hash : pointer_hash <T>, ggc_remove <T *> {};

/* Traits for elements that point to gc memory.  The elements don't
   in themselves keep the pointed-to data alive and they can be deleted
   if the pointed-to data is going to be collected.  */

template <typename T>
struct ggc_cache_ptr_hash : pointer_hash <T>, ggc_cache_remove <T *> {};

/* Traits for string elements that should not be freed when an element
   is deleted.  */

struct nofree_string_hash : string_hash, typed_noop_remove <const char *> {};

template <typename T> struct default_hash_traits : T {};

template <typename T>
struct default_hash_traits <T *> : ggc_ptr_hash <T> {};

#endif