* xvasprintf.c: New file.
[official-gcc.git] / gcc / attribs.c
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1 /* Functions dealing with attribute handling, used by most front ends.
2 Copyright (C) 1992-2014 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
9 version.
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
14 for more details.
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 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "tm.h"
24 #include "tree.h"
25 #include "stringpool.h"
26 #include "attribs.h"
27 #include "stor-layout.h"
28 #include "flags.h"
29 #include "diagnostic-core.h"
30 #include "ggc.h"
31 #include "tm_p.h"
32 #include "cpplib.h"
33 #include "target.h"
34 #include "langhooks.h"
35 #include "hash-table.h"
36 #include "plugin.h"
38 /* Table of the tables of attributes (common, language, format, machine)
39 searched. */
40 static const struct attribute_spec *attribute_tables[4];
42 /* Substring representation. */
44 struct substring
46 const char *str;
47 int length;
50 /* Simple hash function to avoid need to scan whole string. */
52 static inline hashval_t
53 substring_hash (const char *str, int l)
55 return str[0] + str[l - 1] * 256 + l * 65536;
58 /* Used for attribute_hash. */
60 struct attribute_hasher : typed_noop_remove <attribute_spec>
62 typedef attribute_spec value_type;
63 typedef substring compare_type;
64 static inline hashval_t hash (const value_type *);
65 static inline bool equal (const value_type *, const compare_type *);
68 inline hashval_t
69 attribute_hasher::hash (const value_type *spec)
71 const int l = strlen (spec->name);
72 return substring_hash (spec->name, l);
75 inline bool
76 attribute_hasher::equal (const value_type *spec, const compare_type *str)
78 return (strncmp (spec->name, str->str, str->length) == 0
79 && !spec->name[str->length]);
82 /* Scoped attribute name representation. */
84 struct scoped_attributes
86 const char *ns;
87 vec<attribute_spec> attributes;
88 hash_table<attribute_hasher> *attribute_hash;
91 /* The table of scope attributes. */
92 static vec<scoped_attributes> attributes_table;
94 static scoped_attributes* find_attribute_namespace (const char*);
95 static void register_scoped_attribute (const struct attribute_spec *,
96 scoped_attributes *);
98 static bool attributes_initialized = false;
100 /* Default empty table of attributes. */
102 static const struct attribute_spec empty_attribute_table[] =
104 { NULL, 0, 0, false, false, false, NULL, false }
107 /* Return base name of the attribute. Ie '__attr__' is turned into 'attr'.
108 To avoid need for copying, we simply return length of the string. */
110 static void
111 extract_attribute_substring (struct substring *str)
113 if (str->length > 4 && str->str[0] == '_' && str->str[1] == '_'
114 && str->str[str->length - 1] == '_' && str->str[str->length - 2] == '_')
116 str->length -= 4;
117 str->str += 2;
121 /* Insert an array of attributes ATTRIBUTES into a namespace. This
122 array must be NULL terminated. NS is the name of attribute
123 namespace. The function returns the namespace into which the
124 attributes have been registered. */
126 scoped_attributes*
127 register_scoped_attributes (const struct attribute_spec * attributes,
128 const char* ns)
130 scoped_attributes *result = NULL;
132 /* See if we already have attributes in the namespace NS. */
133 result = find_attribute_namespace (ns);
135 if (result == NULL)
137 /* We don't have any namespace NS yet. Create one. */
138 scoped_attributes sa;
140 if (!attributes_table.is_empty ())
141 attributes_table.create (64);
143 memset (&sa, 0, sizeof (sa));
144 sa.ns = ns;
145 sa.attributes.create (64);
146 result = attributes_table.safe_push (sa);
147 result->attribute_hash = new hash_table<attribute_hasher> (200);
150 /* Really add the attributes to their namespace now. */
151 for (unsigned i = 0; attributes[i].name != NULL; ++i)
153 result->attributes.safe_push (attributes[i]);
154 register_scoped_attribute (&attributes[i], result);
157 gcc_assert (result != NULL);
159 return result;
162 /* Return the namespace which name is NS, NULL if none exist. */
164 static scoped_attributes*
165 find_attribute_namespace (const char* ns)
167 unsigned ix;
168 scoped_attributes *iter;
170 FOR_EACH_VEC_ELT (attributes_table, ix, iter)
171 if (ns == iter->ns
172 || (iter->ns != NULL
173 && ns != NULL
174 && !strcmp (iter->ns, ns)))
175 return iter;
176 return NULL;
179 /* Initialize attribute tables, and make some sanity checks
180 if --enable-checking. */
182 void
183 init_attributes (void)
185 size_t i;
187 if (attributes_initialized)
188 return;
190 attribute_tables[0] = lang_hooks.common_attribute_table;
191 attribute_tables[1] = lang_hooks.attribute_table;
192 attribute_tables[2] = lang_hooks.format_attribute_table;
193 attribute_tables[3] = targetm.attribute_table;
195 /* Translate NULL pointers to pointers to the empty table. */
196 for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
197 if (attribute_tables[i] == NULL)
198 attribute_tables[i] = empty_attribute_table;
200 #ifdef ENABLE_CHECKING
201 /* Make some sanity checks on the attribute tables. */
202 for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
204 int j;
206 for (j = 0; attribute_tables[i][j].name != NULL; j++)
208 /* The name must not begin and end with __. */
209 const char *name = attribute_tables[i][j].name;
210 int len = strlen (name);
212 gcc_assert (!(name[0] == '_' && name[1] == '_'
213 && name[len - 1] == '_' && name[len - 2] == '_'));
215 /* The minimum and maximum lengths must be consistent. */
216 gcc_assert (attribute_tables[i][j].min_length >= 0);
218 gcc_assert (attribute_tables[i][j].max_length == -1
219 || (attribute_tables[i][j].max_length
220 >= attribute_tables[i][j].min_length));
222 /* An attribute cannot require both a DECL and a TYPE. */
223 gcc_assert (!attribute_tables[i][j].decl_required
224 || !attribute_tables[i][j].type_required);
226 /* If an attribute requires a function type, in particular
227 it requires a type. */
228 gcc_assert (!attribute_tables[i][j].function_type_required
229 || attribute_tables[i][j].type_required);
233 /* Check that each name occurs just once in each table. */
234 for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
236 int j, k;
237 for (j = 0; attribute_tables[i][j].name != NULL; j++)
238 for (k = j + 1; attribute_tables[i][k].name != NULL; k++)
239 gcc_assert (strcmp (attribute_tables[i][j].name,
240 attribute_tables[i][k].name));
242 /* Check that no name occurs in more than one table. Names that
243 begin with '*' are exempt, and may be overridden. */
244 for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
246 size_t j, k, l;
248 for (j = i + 1; j < ARRAY_SIZE (attribute_tables); j++)
249 for (k = 0; attribute_tables[i][k].name != NULL; k++)
250 for (l = 0; attribute_tables[j][l].name != NULL; l++)
251 gcc_assert (attribute_tables[i][k].name[0] == '*'
252 || strcmp (attribute_tables[i][k].name,
253 attribute_tables[j][l].name));
255 #endif
257 for (i = 0; i < ARRAY_SIZE (attribute_tables); ++i)
258 /* Put all the GNU attributes into the "gnu" namespace. */
259 register_scoped_attributes (attribute_tables[i], "gnu");
261 invoke_plugin_callbacks (PLUGIN_ATTRIBUTES, NULL);
262 attributes_initialized = true;
265 /* Insert a single ATTR into the attribute table. */
267 void
268 register_attribute (const struct attribute_spec *attr)
270 register_scoped_attribute (attr, find_attribute_namespace ("gnu"));
273 /* Insert a single attribute ATTR into a namespace of attributes. */
275 static void
276 register_scoped_attribute (const struct attribute_spec *attr,
277 scoped_attributes *name_space)
279 struct substring str;
280 attribute_spec **slot;
282 gcc_assert (attr != NULL && name_space != NULL);
284 gcc_assert (name_space->attribute_hash);
286 str.str = attr->name;
287 str.length = strlen (str.str);
289 /* Attribute names in the table must be in the form 'text' and not
290 in the form '__text__'. */
291 gcc_assert (str.length > 0 && str.str[0] != '_');
293 slot = name_space->attribute_hash
294 ->find_slot_with_hash (&str, substring_hash (str.str, str.length),
295 INSERT);
296 gcc_assert (!*slot || attr->name[0] == '*');
297 *slot = CONST_CAST (struct attribute_spec *, attr);
300 /* Return the spec for the scoped attribute with namespace NS and
301 name NAME. */
303 static const struct attribute_spec *
304 lookup_scoped_attribute_spec (const_tree ns, const_tree name)
306 struct substring attr;
307 scoped_attributes *attrs;
309 const char *ns_str = (ns != NULL_TREE) ? IDENTIFIER_POINTER (ns): NULL;
311 attrs = find_attribute_namespace (ns_str);
313 if (attrs == NULL)
314 return NULL;
316 attr.str = IDENTIFIER_POINTER (name);
317 attr.length = IDENTIFIER_LENGTH (name);
318 extract_attribute_substring (&attr);
319 return attrs->attribute_hash->find_with_hash (&attr,
320 substring_hash (attr.str,
321 attr.length));
324 /* Return the spec for the attribute named NAME. If NAME is a TREE_LIST,
325 it also specifies the attribute namespace. */
327 const struct attribute_spec *
328 lookup_attribute_spec (const_tree name)
330 tree ns;
331 if (TREE_CODE (name) == TREE_LIST)
333 ns = TREE_PURPOSE (name);
334 name = TREE_VALUE (name);
336 else
337 ns = get_identifier ("gnu");
338 return lookup_scoped_attribute_spec (ns, name);
342 /* Return the namespace of the attribute ATTR. This accessor works on
343 GNU and C++11 (scoped) attributes. On GNU attributes,
344 it returns an identifier tree for the string "gnu".
346 Please read the comments of cxx11_attribute_p to understand the
347 format of attributes. */
349 static tree
350 get_attribute_namespace (const_tree attr)
352 if (cxx11_attribute_p (attr))
353 return TREE_PURPOSE (TREE_PURPOSE (attr));
354 return get_identifier ("gnu");
358 /* Process the attributes listed in ATTRIBUTES and install them in *NODE,
359 which is either a DECL (including a TYPE_DECL) or a TYPE. If a DECL,
360 it should be modified in place; if a TYPE, a copy should be created
361 unless ATTR_FLAG_TYPE_IN_PLACE is set in FLAGS. FLAGS gives further
362 information, in the form of a bitwise OR of flags in enum attribute_flags
363 from tree.h. Depending on these flags, some attributes may be
364 returned to be applied at a later stage (for example, to apply
365 a decl attribute to the declaration rather than to its type). */
367 tree
368 decl_attributes (tree *node, tree attributes, int flags)
370 tree a;
371 tree returned_attrs = NULL_TREE;
373 if (TREE_TYPE (*node) == error_mark_node || attributes == error_mark_node)
374 return NULL_TREE;
376 if (!attributes_initialized)
377 init_attributes ();
379 /* If this is a function and the user used #pragma GCC optimize, add the
380 options to the attribute((optimize(...))) list. */
381 if (TREE_CODE (*node) == FUNCTION_DECL && current_optimize_pragma)
383 tree cur_attr = lookup_attribute ("optimize", attributes);
384 tree opts = copy_list (current_optimize_pragma);
386 if (! cur_attr)
387 attributes
388 = tree_cons (get_identifier ("optimize"), opts, attributes);
389 else
390 TREE_VALUE (cur_attr) = chainon (opts, TREE_VALUE (cur_attr));
393 if (TREE_CODE (*node) == FUNCTION_DECL
394 && optimization_current_node != optimization_default_node
395 && !DECL_FUNCTION_SPECIFIC_OPTIMIZATION (*node))
396 DECL_FUNCTION_SPECIFIC_OPTIMIZATION (*node) = optimization_current_node;
398 /* If this is a function and the user used #pragma GCC target, add the
399 options to the attribute((target(...))) list. */
400 if (TREE_CODE (*node) == FUNCTION_DECL
401 && current_target_pragma
402 && targetm.target_option.valid_attribute_p (*node, NULL_TREE,
403 current_target_pragma, 0))
405 tree cur_attr = lookup_attribute ("target", attributes);
406 tree opts = copy_list (current_target_pragma);
408 if (! cur_attr)
409 attributes = tree_cons (get_identifier ("target"), opts, attributes);
410 else
411 TREE_VALUE (cur_attr) = chainon (opts, TREE_VALUE (cur_attr));
414 /* A "naked" function attribute implies "noinline" and "noclone" for
415 those targets that support it. */
416 if (TREE_CODE (*node) == FUNCTION_DECL
417 && attributes
418 && lookup_attribute_spec (get_identifier ("naked"))
419 && lookup_attribute ("naked", attributes) != NULL)
421 if (lookup_attribute ("noinline", attributes) == NULL)
422 attributes = tree_cons (get_identifier ("noinline"), NULL, attributes);
424 if (lookup_attribute ("noclone", attributes) == NULL)
425 attributes = tree_cons (get_identifier ("noclone"), NULL, attributes);
428 targetm.insert_attributes (*node, &attributes);
430 for (a = attributes; a; a = TREE_CHAIN (a))
432 tree ns = get_attribute_namespace (a);
433 tree name = get_attribute_name (a);
434 tree args = TREE_VALUE (a);
435 tree *anode = node;
436 const struct attribute_spec *spec =
437 lookup_scoped_attribute_spec (ns, name);
438 bool no_add_attrs = 0;
439 int fn_ptr_quals = 0;
440 tree fn_ptr_tmp = NULL_TREE;
442 if (spec == NULL)
444 if (!(flags & (int) ATTR_FLAG_BUILT_IN))
446 if (ns == NULL_TREE || !cxx11_attribute_p (a))
447 warning (OPT_Wattributes, "%qE attribute directive ignored",
448 name);
449 else
450 warning (OPT_Wattributes,
451 "%<%E::%E%> scoped attribute directive ignored",
452 ns, name);
454 continue;
456 else if (list_length (args) < spec->min_length
457 || (spec->max_length >= 0
458 && list_length (args) > spec->max_length))
460 error ("wrong number of arguments specified for %qE attribute",
461 name);
462 continue;
464 gcc_assert (is_attribute_p (spec->name, name));
466 if (TYPE_P (*node)
467 && cxx11_attribute_p (a)
468 && !(flags & ATTR_FLAG_TYPE_IN_PLACE))
470 /* This is a c++11 attribute that appertains to a
471 type-specifier, outside of the definition of, a class
472 type. Ignore it. */
473 warning (OPT_Wattributes, "attribute ignored");
474 inform (input_location,
475 "an attribute that appertains to a type-specifier "
476 "is ignored");
477 continue;
480 if (spec->decl_required && !DECL_P (*anode))
482 if (flags & ((int) ATTR_FLAG_DECL_NEXT
483 | (int) ATTR_FLAG_FUNCTION_NEXT
484 | (int) ATTR_FLAG_ARRAY_NEXT))
486 /* Pass on this attribute to be tried again. */
487 returned_attrs = tree_cons (name, args, returned_attrs);
488 continue;
490 else
492 warning (OPT_Wattributes, "%qE attribute does not apply to types",
493 name);
494 continue;
498 /* If we require a type, but were passed a decl, set up to make a
499 new type and update the one in the decl. ATTR_FLAG_TYPE_IN_PLACE
500 would have applied if we'd been passed a type, but we cannot modify
501 the decl's type in place here. */
502 if (spec->type_required && DECL_P (*anode))
504 anode = &TREE_TYPE (*anode);
505 flags &= ~(int) ATTR_FLAG_TYPE_IN_PLACE;
508 if (spec->function_type_required && TREE_CODE (*anode) != FUNCTION_TYPE
509 && TREE_CODE (*anode) != METHOD_TYPE)
511 if (TREE_CODE (*anode) == POINTER_TYPE
512 && (TREE_CODE (TREE_TYPE (*anode)) == FUNCTION_TYPE
513 || TREE_CODE (TREE_TYPE (*anode)) == METHOD_TYPE))
515 /* OK, this is a bit convoluted. We can't just make a copy
516 of the pointer type and modify its TREE_TYPE, because if
517 we change the attributes of the target type the pointer
518 type needs to have a different TYPE_MAIN_VARIANT. So we
519 pull out the target type now, frob it as appropriate, and
520 rebuild the pointer type later.
522 This would all be simpler if attributes were part of the
523 declarator, grumble grumble. */
524 fn_ptr_tmp = TREE_TYPE (*anode);
525 fn_ptr_quals = TYPE_QUALS (*anode);
526 anode = &fn_ptr_tmp;
527 flags &= ~(int) ATTR_FLAG_TYPE_IN_PLACE;
529 else if (flags & (int) ATTR_FLAG_FUNCTION_NEXT)
531 /* Pass on this attribute to be tried again. */
532 returned_attrs = tree_cons (name, args, returned_attrs);
533 continue;
536 if (TREE_CODE (*anode) != FUNCTION_TYPE
537 && TREE_CODE (*anode) != METHOD_TYPE)
539 warning (OPT_Wattributes,
540 "%qE attribute only applies to function types",
541 name);
542 continue;
546 if (TYPE_P (*anode)
547 && (flags & (int) ATTR_FLAG_TYPE_IN_PLACE)
548 && TYPE_SIZE (*anode) != NULL_TREE)
550 warning (OPT_Wattributes, "type attributes ignored after type is already defined");
551 continue;
554 if (spec->handler != NULL)
556 int cxx11_flag =
557 cxx11_attribute_p (a) ? ATTR_FLAG_CXX11 : 0;
559 returned_attrs = chainon ((*spec->handler) (anode, name, args,
560 flags|cxx11_flag,
561 &no_add_attrs),
562 returned_attrs);
565 /* Layout the decl in case anything changed. */
566 if (spec->type_required && DECL_P (*node)
567 && (TREE_CODE (*node) == VAR_DECL
568 || TREE_CODE (*node) == PARM_DECL
569 || TREE_CODE (*node) == RESULT_DECL))
570 relayout_decl (*node);
572 if (!no_add_attrs)
574 tree old_attrs;
575 tree a;
577 if (DECL_P (*anode))
578 old_attrs = DECL_ATTRIBUTES (*anode);
579 else
580 old_attrs = TYPE_ATTRIBUTES (*anode);
582 for (a = lookup_attribute (spec->name, old_attrs);
583 a != NULL_TREE;
584 a = lookup_attribute (spec->name, TREE_CHAIN (a)))
586 if (simple_cst_equal (TREE_VALUE (a), args) == 1)
587 break;
590 if (a == NULL_TREE)
592 /* This attribute isn't already in the list. */
593 if (DECL_P (*anode))
594 DECL_ATTRIBUTES (*anode) = tree_cons (name, args, old_attrs);
595 else if (flags & (int) ATTR_FLAG_TYPE_IN_PLACE)
597 TYPE_ATTRIBUTES (*anode) = tree_cons (name, args, old_attrs);
598 /* If this is the main variant, also push the attributes
599 out to the other variants. */
600 if (*anode == TYPE_MAIN_VARIANT (*anode))
602 tree variant;
603 for (variant = *anode; variant;
604 variant = TYPE_NEXT_VARIANT (variant))
606 if (TYPE_ATTRIBUTES (variant) == old_attrs)
607 TYPE_ATTRIBUTES (variant)
608 = TYPE_ATTRIBUTES (*anode);
609 else if (!lookup_attribute
610 (spec->name, TYPE_ATTRIBUTES (variant)))
611 TYPE_ATTRIBUTES (variant) = tree_cons
612 (name, args, TYPE_ATTRIBUTES (variant));
616 else
617 *anode = build_type_attribute_variant (*anode,
618 tree_cons (name, args,
619 old_attrs));
623 if (fn_ptr_tmp)
625 /* Rebuild the function pointer type and put it in the
626 appropriate place. */
627 fn_ptr_tmp = build_pointer_type (fn_ptr_tmp);
628 if (fn_ptr_quals)
629 fn_ptr_tmp = build_qualified_type (fn_ptr_tmp, fn_ptr_quals);
630 if (DECL_P (*node))
631 TREE_TYPE (*node) = fn_ptr_tmp;
632 else
634 gcc_assert (TREE_CODE (*node) == POINTER_TYPE);
635 *node = fn_ptr_tmp;
640 return returned_attrs;
643 /* Return TRUE iff ATTR has been parsed by the front-end as a C++-11
644 attribute.
646 When G++ parses a C++11 attribute, it is represented as
647 a TREE_LIST which TREE_PURPOSE is itself a TREE_LIST. TREE_PURPOSE
648 (TREE_PURPOSE (ATTR)) is the namespace of the attribute, and the
649 TREE_VALUE (TREE_PURPOSE (ATTR)) is its non-qualified name. Please
650 use get_attribute_namespace and get_attribute_name to retrieve the
651 namespace and name of the attribute, as these accessors work with
652 GNU attributes as well. */
654 bool
655 cxx11_attribute_p (const_tree attr)
657 if (attr == NULL_TREE
658 || TREE_CODE (attr) != TREE_LIST)
659 return false;
661 return (TREE_CODE (TREE_PURPOSE (attr)) == TREE_LIST);
664 /* Return the name of the attribute ATTR. This accessor works on GNU
665 and C++11 (scoped) attributes.
667 Please read the comments of cxx11_attribute_p to understand the
668 format of attributes. */
670 tree
671 get_attribute_name (const_tree attr)
673 if (cxx11_attribute_p (attr))
674 return TREE_VALUE (TREE_PURPOSE (attr));
675 return TREE_PURPOSE (attr);
678 /* Subroutine of set_method_tm_attributes. Apply TM attribute ATTR
679 to the method FNDECL. */
681 void
682 apply_tm_attr (tree fndecl, tree attr)
684 decl_attributes (&TREE_TYPE (fndecl), tree_cons (attr, NULL, NULL), 0);