1 /* String pool for GCC.
2 Copyright (C) 2000-2013 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /* String text, identifier text and identifier node allocator.
21 Identifiers are uniquely stored in a hash table.
23 We use cpplib's hash table implementation. libiberty's
24 hashtab.c is not used because it requires 100% average space
25 overhead per string, which is unacceptable. Also, this algorithm
30 #include "coretypes.h"
32 #include "ggc-internal.h"
37 /* The "" allocated string. */
38 const char empty_string
[] = "";
40 /* Character strings, each containing a single decimal digit.
41 Written this way to save space. */
42 static const char digit_vector
[] = {
43 '0', 0, '1', 0, '2', 0, '3', 0, '4', 0,
44 '5', 0, '6', 0, '7', 0, '8', 0, '9', 0
47 #define digit_string(d) (digit_vector + ((d) * 2))
49 struct ht
*ident_hash
;
51 static hashnode
alloc_node (cpp_hash_table
*);
52 static int mark_ident (struct cpp_reader
*, hashnode
, const void *);
55 stringpool_ggc_alloc (size_t x
)
57 return ggc_alloc_atomic (x
);
60 /* Initialize the string pool. */
62 init_stringpool (void)
64 /* Create with 16K (2^14) entries. */
65 ident_hash
= ht_create (14);
66 ident_hash
->alloc_node
= alloc_node
;
67 ident_hash
->alloc_subobject
= stringpool_ggc_alloc
;
70 /* Allocate a hash node. */
72 alloc_node (cpp_hash_table
*table ATTRIBUTE_UNUSED
)
74 return GCC_IDENT_TO_HT_IDENT (make_node (IDENTIFIER_NODE
));
77 /* Allocate and return a string constant of length LENGTH, containing
78 CONTENTS. If LENGTH is -1, CONTENTS is assumed to be a
79 nul-terminated string, and the length is calculated using strlen. */
82 ggc_alloc_string_stat (const char *contents
, int length MEM_STAT_DECL
)
87 length
= strlen (contents
);
91 if (length
== 1 && ISDIGIT (contents
[0]))
92 return digit_string (contents
[0] - '0');
94 result
= (char *) ggc_alloc_atomic_stat (length
+ 1 PASS_MEM_STAT
);
95 memcpy (result
, contents
, length
);
96 result
[length
] = '\0';
97 return (const char *) result
;
100 /* Return an IDENTIFIER_NODE whose name is TEXT (a null-terminated string).
101 If an identifier with that name has previously been referred to,
102 the same node is returned this time. */
104 #undef get_identifier
107 get_identifier (const char *text
)
109 hashnode ht_node
= ht_lookup (ident_hash
,
110 (const unsigned char *) text
,
111 strlen (text
), HT_ALLOC
);
113 /* ht_node can't be NULL here. */
114 return HT_IDENT_TO_GCC_IDENT (ht_node
);
117 /* Identical to get_identifier, except that the length is assumed
121 get_identifier_with_length (const char *text
, size_t length
)
123 hashnode ht_node
= ht_lookup (ident_hash
,
124 (const unsigned char *) text
,
127 /* ht_node can't be NULL here. */
128 return HT_IDENT_TO_GCC_IDENT (ht_node
);
131 /* If an identifier with the name TEXT (a null-terminated string) has
132 previously been referred to, return that node; otherwise return
136 maybe_get_identifier (const char *text
)
140 ht_node
= ht_lookup (ident_hash
, (const unsigned char *) text
,
141 strlen (text
), HT_NO_INSERT
);
143 return HT_IDENT_TO_GCC_IDENT (ht_node
);
148 /* Report some basic statistics about the string pool. */
151 stringpool_statistics (void)
153 ht_dump_statistics (ident_hash
);
156 /* Mark an identifier for GC. */
159 mark_ident (struct cpp_reader
*pfile ATTRIBUTE_UNUSED
, hashnode h
,
160 const void *v ATTRIBUTE_UNUSED
)
162 gt_ggc_m_9tree_node (HT_IDENT_TO_GCC_IDENT (h
));
166 /* Return true if an identifier should be removed from the table. */
169 maybe_delete_ident (struct cpp_reader
*pfile ATTRIBUTE_UNUSED
, hashnode h
,
170 const void *v ATTRIBUTE_UNUSED
)
172 return !ggc_marked_p (HT_IDENT_TO_GCC_IDENT (h
));
175 /* Mark the trees hanging off the identifier node for GGC. These are
176 handled specially (not using gengtype) because identifiers are only
177 roots during one part of compilation. */
180 ggc_mark_stringpool (void)
182 ht_forall (ident_hash
, mark_ident
, NULL
);
185 /* Purge the identifier hash of identifiers which are no longer
189 ggc_purge_stringpool (void)
191 ht_purge (ident_hash
, maybe_delete_ident
, NULL
);
194 /* Pointer-walking routine for strings (not very interesting, since
195 strings don't contain pointers). */
198 gt_pch_p_S (void *obj ATTRIBUTE_UNUSED
, void *x ATTRIBUTE_UNUSED
,
199 gt_pointer_operator op ATTRIBUTE_UNUSED
,
200 void *cookie ATTRIBUTE_UNUSED
)
204 /* PCH pointer-walking routine for strings. */
207 gt_pch_n_S (const void *x
)
209 gt_pch_note_object (CONST_CAST (void *, x
), CONST_CAST (void *, x
),
210 >_pch_p_S
, gt_types_enum_last
);
214 /* User-callable entry point for marking string X. */
217 gt_pch_nx (const char *& x
)
223 gt_pch_nx (unsigned char *& x
)
229 gt_pch_nx (unsigned char& x ATTRIBUTE_UNUSED
)
234 gt_pch_nx (unsigned char *x
, gt_pointer_operator op
, void *cookie
)
239 /* Handle saving and restoring the string pool for PCH. */
241 /* SPD is saved in the PCH file and holds the information needed
242 to restore the string pool. */
244 struct GTY(()) string_pool_data
{
246 GTY((length ("%h.nslots"),
247 nested_ptr (union tree_node
, "%h ? GCC_IDENT_TO_HT_IDENT (%h) : NULL",
248 "%h ? HT_IDENT_TO_GCC_IDENT (%h) : NULL")))
251 unsigned int nelements
;
254 static GTY(()) struct string_pool_data
* spd
;
256 /* Save the stringpool data in SPD. */
259 gt_pch_save_stringpool (void)
261 spd
= ggc_alloc_string_pool_data ();
262 spd
->nslots
= ident_hash
->nslots
;
263 spd
->nelements
= ident_hash
->nelements
;
264 spd
->entries
= ggc_alloc_vec_ht_identifier_ptr (spd
->nslots
);
265 memcpy (spd
->entries
, ident_hash
->entries
,
266 spd
->nslots
* sizeof (spd
->entries
[0]));
269 /* Return the stringpool to its state before gt_pch_save_stringpool
273 gt_pch_fixup_stringpool (void)
277 /* A PCH file has been restored, which loaded SPD; fill the real hash table
281 gt_pch_restore_stringpool (void)
283 ht_load (ident_hash
, spd
->entries
, spd
->nslots
, spd
->nelements
, false);
287 #include "gt-stringpool.h"