GCC Middle and Back End API Reference
attribs.h
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1/* Declarations and definitions dealing with attribute handling.
2 Copyright (C) 2013-2024 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3. If not see
18<http://www.gnu.org/licenses/>. */
19
20#ifndef GCC_ATTRIBS_H
21#define GCC_ATTRIBS_H
22
23/* A set of attributes that belong to the same namespace, given by NS. */
29
30extern const struct attribute_spec *lookup_attribute_spec (const_tree);
31extern void free_attr_data ();
32extern void init_attributes (void);
33
34/* Process the attributes listed in ATTRIBUTES and install them in *NODE,
35 which is either a DECL (including a TYPE_DECL) or a TYPE. If a DECL,
36 it should be modified in place; if a TYPE, a copy should be created
37 unless ATTR_FLAG_TYPE_IN_PLACE is set in FLAGS. FLAGS gives further
38 information, in the form of a bitwise OR of flags in enum attribute_flags
39 from tree.h. Depending on these flags, some attributes may be
40 returned to be applied at a later stage (for example, to apply
41 a decl attribute to the declaration rather than to its type). */
42extern tree decl_attributes (tree *, tree, int, tree = NULL_TREE);
43
44extern bool cxx11_attribute_p (const_tree);
47extern void apply_tm_attr (tree, tree);
48extern tree make_attribute (const char *, const char *, tree);
49extern bool attribute_ignored_p (tree);
50extern bool attribute_ignored_p (const attribute_spec *const);
52
53extern struct scoped_attributes *
55
56extern char *sorted_attr_string (tree);
58extern tree make_dispatcher_decl (const tree);
59extern bool is_function_default_version (const tree);
61
62/* Return a type like TTYPE except that its TYPE_ATTRIBUTES
63 is ATTRIBUTE.
64
65 Such modified types already made are recorded so that duplicates
66 are not made. */
67
71
74
75/* Return 0 if the attributes for two types are incompatible, 1 if they
76 are compatible, and 2 if they are nearly compatible (which causes a
77 warning to be generated). */
79
80extern tree affects_type_identity_attributes (tree, bool = true);
82
83/* Default versions of target-overridable functions. */
86
87/* Remove any instances of attribute ATTR_NAME in LIST and return the
88 modified list. */
89
90extern tree remove_attribute (const char *, tree);
91
92/* Similarly but also with specific attribute namespace. */
93
94extern tree remove_attribute (const char *, const char *, tree);
95
96/* Given two attributes lists, return a list of their union. */
97
99
100/* Duplicate all attributes with name NAME in ATTR list to *ATTRS if
101 they are missing there. */
102
103extern void duplicate_one_attribute (tree *, tree, const char *);
104
105/* Duplicate all attributes from user DECL to the corresponding
106 builtin that should be propagated. */
107
108extern void copy_attributes_to_builtin (tree);
109
110/* Given two Windows decl attributes lists, possibly including
111 dllimport, return a list of their union . */
113
114/* Handle a "dllimport" or "dllexport" attribute. */
115extern tree handle_dll_attribute (tree *, tree, tree, int, bool *);
116
119
120/* The backbone of lookup_attribute(). ATTR_LEN is the string length
121 of ATTR_NAME, and LIST is not NULL_TREE.
122
123 The function is called from lookup_attribute in order to optimize
124 for size. */
125extern tree private_lookup_attribute (const char *attr_name, size_t attr_len,
126 tree list);
127extern tree private_lookup_attribute (const char *attr_ns,
128 const char *attr_name,
129 size_t attr_ns_len, size_t attr_len,
130 tree list);
131
132extern unsigned decls_mismatched_attributes (tree, tree, tree,
133 const char* const[],
135
137
138/* For a given string S of length L, strip leading and trailing '_' characters
139 so that we have a canonical form of attribute names. NB: This function may
140 change S and L. */
141
142template <typename T>
143inline bool
144canonicalize_attr_name (const char *&s, T &l)
145{
146 if (l > 4 && s[0] == '_' && s[1] == '_' && s[l - 1] == '_' && s[l - 2] == '_')
147 {
148 s += 2;
149 l -= 4;
150 return true;
151 }
152 return false;
153}
154
155/* For a given IDENTIFIER_NODE, strip leading and trailing '_' characters
156 so that we have a canonical form of attribute names. */
157
158inline tree
160{
161 size_t l = IDENTIFIER_LENGTH (attr_name);
162 const char *s = IDENTIFIER_POINTER (attr_name);
163
164 if (canonicalize_attr_name (s, l))
165 return get_identifier_with_length (s, l);
166
167 return attr_name;
168}
169
170/* Compare attribute identifiers ATTR1 and ATTR2 with length ATTR1_LEN and
171 ATTR2_LEN. */
172
173inline bool
174cmp_attribs (const char *attr1, size_t attr1_len,
175 const char *attr2, size_t attr2_len)
176{
177 return attr1_len == attr2_len && strncmp (attr1, attr2, attr1_len) == 0;
178}
179
180/* Compare attribute identifiers ATTR1 and ATTR2. */
181
182inline bool
183cmp_attribs (const char *attr1, const char *attr2)
184{
185 return cmp_attribs (attr1, strlen (attr1), attr2, strlen (attr2));
186}
187
188/* Given an identifier node IDENT and a string ATTR_NAME, return true
189 if the identifier node is a valid attribute name for the string. */
190
191inline bool
192is_attribute_p (const char *attr_name, const_tree ident)
193{
194 return cmp_attribs (attr_name, strlen (attr_name),
195 IDENTIFIER_POINTER (ident), IDENTIFIER_LENGTH (ident));
196}
197
198/* Given an attribute ATTR and a string ATTR_NS, return true
199 if the attribute namespace is valid for the string. ATTR_NS "" stands
200 for standard attribute (NULL get_attribute_namespace) or "gnu"
201 namespace. */
202
203inline bool
204is_attribute_namespace_p (const char *attr_ns, const_tree attr)
205{
206 tree ident = get_attribute_namespace (attr);
207 if (attr_ns == NULL)
208 return ident == NULL_TREE;
209 if (attr_ns[0])
210 return ident && is_attribute_p (attr_ns, ident);
211 return ident == NULL_TREE || is_attribute_p ("gnu", ident);
212}
213
214/* Given an attribute name ATTR_NAME and a list of attributes LIST,
215 return a pointer to the attribute's list element if the attribute
216 is part of the list, or NULL_TREE if not found. If the attribute
217 appears more than once, this only returns the first occurrence; the
218 TREE_CHAIN of the return value should be passed back in if further
219 occurrences are wanted. ATTR_NAME must be in the form 'text' (not
220 '__text__'). */
221
222inline tree
223lookup_attribute (const char *attr_name, tree list)
224{
225 if (CHECKING_P && attr_name[0] != '_')
226 {
227 size_t attr_len = strlen (attr_name);
228 gcc_checking_assert (!canonicalize_attr_name (attr_name, attr_len));
229 }
230 /* In most cases, list is NULL_TREE. */
231 if (list == NULL_TREE)
232 return NULL_TREE;
233 else
234 {
235 size_t attr_len = strlen (attr_name);
236 /* Do the strlen() before calling the out-of-line implementation.
237 In most cases attr_name is a string constant, and the compiler
238 will optimize the strlen() away. */
239 return private_lookup_attribute (attr_name, attr_len, list);
240 }
241}
242
243/* Similar to lookup_attribute, but also match the attribute namespace.
244 ATTR_NS "" stands for either standard attribute or "gnu" namespace. */
245
246inline tree
247lookup_attribute (const char *attr_ns, const char *attr_name, tree list)
248{
249 if (CHECKING_P && attr_name[0] != '_')
250 {
251 size_t attr_len = strlen (attr_name);
252 gcc_checking_assert (!canonicalize_attr_name (attr_name, attr_len));
253 }
254 if (CHECKING_P && attr_ns && attr_ns[0] != '_')
255 {
256 size_t attr_ns_len = strlen (attr_ns);
257 gcc_checking_assert (!canonicalize_attr_name (attr_ns, attr_ns_len));
258 }
259 /* In most cases, list is NULL_TREE. */
260 if (list == NULL_TREE)
261 return NULL_TREE;
262 else
263 {
264 size_t attr_ns_len = attr_ns ? strlen (attr_ns) : 0;
265 size_t attr_len = strlen (attr_name);
266 /* Do the strlen() before calling the out-of-line implementation.
267 In most cases attr_name is a string constant, and the compiler
268 will optimize the strlen() away. */
269 return private_lookup_attribute (attr_ns, attr_name,
270 attr_ns_len, attr_len, list);
271 }
272}
273
274/* Given an attribute name ATTR_NAME and a list of attributes LIST,
275 return a pointer to the attribute's list first element if the attribute
276 starts with ATTR_NAME. ATTR_NAME must be in the form 'text' (not
277 '__text__'). */
278
279inline tree
280lookup_attribute_by_prefix (const char *attr_name, tree list)
281{
282 gcc_checking_assert (attr_name[0] != '_');
283 /* In most cases, list is NULL_TREE. */
284 if (list == NULL_TREE)
285 return NULL_TREE;
286 else
287 {
288 size_t attr_len = strlen (attr_name);
289 while (list)
290 {
291 tree name = get_attribute_name (list);
292 size_t ident_len = IDENTIFIER_LENGTH (name);
293
294 if (attr_len > ident_len)
295 {
296 list = TREE_CHAIN (list);
297 continue;
298 }
299
300 const char *p = IDENTIFIER_POINTER (name);
301 gcc_checking_assert (attr_len == 0 || p[0] != '_'
302 || (ident_len > 1 && p[1] != '_'));
303 if (strncmp (attr_name, p, attr_len) == 0)
304 break;
305
306 list = TREE_CHAIN (list);
307 }
308
309 return list;
310 }
311}
312
313/* Description of a function argument declared with attribute access.
314 Used as an "iterator" over all such arguments in a function declaration
315 or call. */
316
318{
319 /* The beginning and end of the internal string representation. */
320 const char *str, *end;
321 /* The attribute pointer argument. */
323 /* For a declaration, a TREE_CHAIN of VLA bound expressions stored
324 in TREE_VALUE and their positions in the argument list (stored
325 in TREE_PURPOSE). Each expression may be a PARM_DECL or some
326 other DECL (for ordinary variables), or an EXPR for other
327 expressions (e.g., function calls). */
329
330 /* The zero-based position of each of the formal function arguments.
331 For the optional SIZARG, UINT_MAX when not specified. For VLAs
332 with multiple variable bounds, SIZARG is the position corresponding
333 to the most significant bound in the argument list. Positions of
334 subsequent bounds are in the TREE_PURPOSE field of the SIZE chain. */
335 unsigned ptrarg;
336 unsigned sizarg;
337 /* For internal specifications only, the constant minimum size of
338 the array, zero if not specified, and HWI_M1U for the unspecified
339 VLA [*] notation. Meaningless for external (explicit) access
340 specifications. */
341 unsigned HOST_WIDE_INT minsize;
342
343 /* The access mode. */
345
346 /* Set for an attribute added internally rather than by an explicit
347 declaration. */
349 /* Set for the T[static MINSIZE] array notation for nonzero MINSIZE
350 less than HWI_M1U. */
352
353 /* Return the number of specified VLA bounds. */
354 unsigned vla_bounds (unsigned *) const;
355
356 /* Return internal representation as STRING_CST. */
357 tree to_internal_string () const;
358
359 /* Return the human-readable representation of the external attribute
360 specification (as it might appear in the source code) as STRING_CST. */
361 tree to_external_string () const;
362
363 /* Return argument of array type formatted as a readable string. */
364 std::string array_as_string (tree) const;
365
366 /* Return the access mode corresponding to the character code. */
367 static access_mode from_mode_char (char);
368
369 /* Reset front end-specific attribute access data from attributes. */
370 static void free_lang_data (tree);
371
372 /* The character codes corresponding to all the access modes. */
373 static constexpr char mode_chars[5] = { '-', 'r', 'w', 'x', '^' };
374
375 /* The strings corresponding to just the external access modes. */
376 static constexpr char mode_names[4][11] =
377 {
378 "none", "read_only", "write_only", "read_write"
379 };
380};
381
382inline access_mode
384{
385 switch (c)
386 {
387 case mode_chars[access_none]: return access_none;
392 }
394}
395
396/* Used to define rdwr_map below. */
397struct rdwr_access_hash: int_hash<int, -1> { };
398
399/* A mapping between argument number corresponding to attribute access
400 mode (read_only, write_only, or read_write) and operands. */
401struct attr_access;
403
404extern void init_attr_rdwr_indices (rdwr_map *, tree);
407
408#endif // GCC_ATTRIBS_H
void maybe_diag_alias_attributes(tree, tree)
Definition attribs.cc:2302
bool is_function_default_version(const tree)
Definition attribs.cc:1280
bool simple_cst_list_equal(const_tree, const_tree)
Definition attribs.cc:1392
int attribute_list_contained(const_tree, const_tree)
Definition attribs.cc:2059
tree build_type_attribute_variant(tree, tree)
Definition attribs.cc:1637
hash_map< rdwr_access_hash, attr_access > rdwr_map
Definition attribs.h:402
int comp_type_attributes(const_tree, const_tree)
Definition attribs.cc:1493
void init_attributes(void)
Definition attribs.cc:317
tree lookup_attribute_by_prefix(const char *attr_name, tree list)
Definition attribs.h:280
char * sorted_attr_string(tree)
Definition attribs.cc:1109
bool attribute_value_equal(const_tree, const_tree)
Definition attribs.cc:1453
tree make_dispatcher_decl(const tree)
Definition attribs.cc:1248
bool is_attribute_namespace_p(const char *attr_ns, const_tree attr)
Definition attribs.h:204
tree private_lookup_attribute(const char *attr_name, size_t attr_len, tree list)
Definition attribs.cc:2106
tree merge_dllimport_decl_attributes(tree, tree)
tree decl_attributes(tree *, tree, int, tree=NULL_TREE)
Definition attribs.cc:622
tree build_type_attribute_qual_variant(tree, tree, int)
Definition attribs.cc:1308
struct scoped_attributes * register_scoped_attributes(const scoped_attribute_specs &, bool=false)
Definition attribs.cc:125
void duplicate_one_attribute(tree *, tree, const char *)
Definition attribs.cc:1794
bool cxx11_attribute_p(const_tree)
Definition attribs.cc:1039
const struct attribute_spec * lookup_attribute_spec(const_tree)
Definition attribs.cc:401
bool any_nonignored_attribute_p(tree)
Definition attribs.cc:586
tree get_attribute_name(const_tree)
Definition attribs.cc:1055
tree merge_attributes(tree, tree)
Definition attribs.cc:1727
bool attribute_ignored_p(tree)
Definition attribs.cc:559
void apply_tm_attr(tree, tree)
Definition attribs.cc:1066
void copy_attributes_to_builtin(tree)
Definition attribs.cc:1820
int attribute_list_equal(const_tree, const_tree)
Definition attribs.cc:2041
attr_access * get_parm_access(rdwr_map &, tree, tree=current_function_decl)
Definition attribs.cc:2512
tree affects_type_identity_attributes(tree, bool=true)
Definition attribs.cc:1599
bool common_function_versions(tree, tree)
Definition attribs.cc:1184
tree make_attribute(const char *, const char *, tree)
Definition attribs.cc:1075
tree merge_type_attributes(tree, tree)
Definition attribs.cc:1774
unsigned decls_mismatched_attributes(tree, tree, tree, const char *const[], pretty_printer *)
Definition attribs.cc:2205
tree remove_attribute(const char *, tree)
Definition attribs.cc:1678
tree build_decl_attribute_variant(tree, tree)
Definition attribs.cc:1296
bool cmp_attribs(const char *attr1, size_t attr1_len, const char *attr2, size_t attr2_len)
Definition attribs.h:174
bool canonicalize_attr_name(const char *&s, T &l)
Definition attribs.h:144
tree handle_dll_attribute(tree *, tree, tree, int, bool *)
tree restrict_type_identity_attributes_to(tree, tree)
Definition attribs.cc:1612
tree get_attribute_namespace(const_tree)
Definition attribs.cc:423
bool is_attribute_p(const char *attr_name, const_tree ident)
Definition attribs.h:192
tree lookup_attribute(const char *attr_name, tree list)
Definition attribs.h:223
void init_attr_rdwr_indices(rdwr_map *, tree)
Definition attribs.cc:2363
tree merge_decl_attributes(tree, tree)
Definition attribs.cc:1784
void free_attr_data()
Definition attribs.cc:306
void handle_ignored_attributes_option(vec< char * > *)
Definition attribs.cc:230
Definition vec.h:2362
Definition hash-map.h:40
Definition pretty-print.h:255
const union tree_node * const_tree
Definition coretypes.h:98
union tree_node * tree
Definition coretypes.h:97
tree get_identifier_with_length(const char *text, size_t length)
Definition stringpool.cc:119
Definition attribs.h:318
static void free_lang_data(tree)
Definition attribs.cc:2580
access_mode mode
Definition attribs.h:344
tree to_internal_string() const
Definition attribs.cc:2534
static constexpr char mode_names[4][11]
Definition attribs.h:376
const char * str
Definition attribs.h:320
tree ptr
Definition attribs.h:322
static constexpr char mode_chars[5]
Definition attribs.h:373
unsigned ptrarg
Definition attribs.h:335
bool static_p
Definition attribs.h:351
const char * end
Definition attribs.h:320
bool internal_p
Definition attribs.h:348
tree to_external_string() const
Definition attribs.cc:2544
static access_mode from_mode_char(char)
Definition attribs.h:383
unsigned sizarg
Definition attribs.h:336
tree size
Definition attribs.h:328
unsigned HOST_WIDE_INT minsize
Definition attribs.h:341
std::string array_as_string(tree) const
Definition attribs.cc:2624
unsigned vla_bounds(unsigned *) const
Definition attribs.cc:2560
Definition hash-traits.h:122
Definition attribs.h:397
Definition attribs.h:25
const char * ns
Definition attribs.h:26
array_slice< const attribute_spec > attributes
Definition attribs.h:27
Definition attribs.cc:87
Definition vec.h:450
#define NULL
Definition system.h:50
#define gcc_unreachable()
Definition system.h:848
#define gcc_checking_assert(EXPR)
Definition system.h:828
tree current_function_decl
Definition toplev.cc:124
#define IDENTIFIER_LENGTH(NODE)
Definition tree.h:1194
#define TREE_CHAIN(NODE)
Definition tree.h:511
#define IDENTIFIER_POINTER(NODE)
Definition tree.h:1196
access_mode
Definition tree.h:5846
@ access_deferred
Definition tree.h:5851
@ access_none
Definition tree.h:5847
@ access_read_write
Definition tree.h:5850
@ access_write_only
Definition tree.h:5849
@ access_read_only
Definition tree.h:5848
#define NULL_TREE
Definition tree.h:317