1 /* Declarations for -*- C++ -*- name lookup routines.
2 Copyright (C) 2003-2023 Free Software Foundation, Inc.
3 Contributed by Gabriel Dos Reis <gdr@integrable-solutions.net>
4
5 This file is part of GCC.
6
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
11
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
20
21 #ifndef GCC_CP_NAME_LOOKUP_H
22 #define GCC_CP_NAME_LOOKUP_H
23
24 #include "c-family/c-common.h"
25
26
27 /* The datatype used to implement C++ scope. */
28 struct cp_binding_level;
29
30 /* Nonzero if this binding is for a local scope, as opposed to a class
31 or namespace scope. */
32 #define LOCAL_BINDING_P(NODE) ((NODE)->is_local)
33
34 /* True if NODE->value is from a base class of the class which is
35 currently being defined. */
36 #define INHERITED_VALUE_BINDING_P(NODE) ((NODE)->value_is_inherited)
37
38 /* The IMPLICIT_TYPEDEF is hidden from ordinary name lookup (it was
39 injected via a local class's friend decl). The typdef may be in the
40 VALUE or the TYPE slot. We do not get the situation where the
41 value and type slots are both filled and both hidden. */
42 #define HIDDEN_TYPE_BINDING_P(NODE) ((NODE)->type_is_hidden)
43
44 /* Datatype that represents binding established by a declaration between
45 a name and a C++ entity. */
46 struct GTY(()) cxx_binding {
47 /* Link to chain together various bindings for this name. */
48 cxx_binding *previous;
49 /* The non-type entity this name is bound to. */
50 tree value;
51 /* The type entity this name is bound to. */
52 tree type;
53 /* The scope at which this binding was made. */
54 cp_binding_level *scope;
55
56 bool value_is_inherited : 1;
57 bool is_local : 1;
58 bool type_is_hidden : 1;
59 };
60
61 /* Datatype used to temporarily save C++ bindings (for implicit
62 instantiations purposes and like). Implemented in decl.cc. */
63 struct GTY(()) cxx_saved_binding {
64 /* The name of the current binding. */
65 tree identifier;
66 /* The binding we're saving. */
67 cxx_binding *binding;
68 tree real_type_value;
69 };
70
71 /* To support lazy module loading, we squirrel away a section number
72 (and a couple of flags) in the binding slot of unloaded bindings.
73 We rely on pointers being aligned and setting the bottom bit to
74 mark a lazy value. GTY doesn't like an array of union, so we have
75 a containing struct. */
76
77 struct GTY(()) binding_slot {
78 union GTY((desc ("%1.is_lazy ()"))) binding_slot_lazy {
79 tree GTY((tag ("false"))) binding;
80 } u;
81
82 operator tree & ()
83 {
84 gcc_checking_assert (!is_lazy ());
85 return u.binding;
86 }
87 binding_slot &operator= (tree t)
88 {
89 u.binding = t;
90 return *this;
91 }
92 bool is_lazy () const
93 {
94 return bool (uintptr_t (u.binding) & 1);
95 }
96 void set_lazy (unsigned snum)
97 {
98 gcc_checking_assert (!u.binding);
99 u.binding = tree (uintptr_t ((snum << 1) | 1));
100 }
101 void or_lazy (unsigned snum)
102 {
103 gcc_checking_assert (is_lazy ());
104 u.binding = tree (uintptr_t (u.binding) | (snum << 1));
105 }
106 unsigned get_lazy () const
107 {
108 gcc_checking_assert (is_lazy ());
109 return unsigned (uintptr_t (u.binding) >> 1);
110 }
111 };
112
113 /* Bindings for modules are held in a sparse array. There is always a
114 current TU slot, others are allocated as needed. By construction
115 of the importing mechanism we only ever need to append to the
116 array. Rather than have straight index/slot tuples, we bunch them
117 up for greater packing.
118
119 The cluster representation packs well on a 64-bit system. */
120
121 #define BINDING_VECTOR_SLOTS_PER_CLUSTER 2
122 struct binding_index {
123 unsigned short base;
124 unsigned short span;
125 };
126
127 struct GTY(()) binding_cluster
128 {
129 binding_index GTY((skip)) indices[BINDING_VECTOR_SLOTS_PER_CLUSTER];
130 binding_slot slots[BINDING_VECTOR_SLOTS_PER_CLUSTER];
131 };
132
133 /* These two fields overlay lang flags. So don't use those. */
134 #define BINDING_VECTOR_ALLOC_CLUSTERS(NODE) \
135 (BINDING_VECTOR_CHECK (NODE)->base.u.dependence_info.clique)
136 #define BINDING_VECTOR_NUM_CLUSTERS(NODE) \
137 (BINDING_VECTOR_CHECK (NODE)->base.u.dependence_info.base)
138 #define BINDING_VECTOR_CLUSTER_BASE(NODE) \
139 (((tree_binding_vec *)BINDING_VECTOR_CHECK (NODE))->vec)
140 #define BINDING_VECTOR_CLUSTER_LAST(NODE) \
141 (&BINDING_VECTOR_CLUSTER (NODE, BINDING_VECTOR_NUM_CLUSTERS (NODE) - 1))
142 #define BINDING_VECTOR_CLUSTER(NODE,IX) \
143 (((tree_binding_vec *)BINDING_VECTOR_CHECK (NODE))->vec[IX])
144
145 struct GTY(()) tree_binding_vec {
146 struct tree_base base;
147 tree name;
148 binding_cluster GTY((length ("%h.base.u.dependence_info.base"))) vec[1];
149 };
150
151 /* The name of a module vector. */
152 #define BINDING_VECTOR_NAME(NODE) \
153 (((tree_binding_vec *)BINDING_VECTOR_CHECK (NODE))->name)
154
155 /* tree_binding_vec does uses base.u.dependence_info.base field for
156 length. It does not have lang_flag etc available! */
157
158 /* These two flags note if a module-vector contains deduplicated
159 bindings (i.e. multiple declarations in different imports). */
160 /* This binding contains duplicate references to a global module
161 entity. */
162 #define BINDING_VECTOR_GLOBAL_DUPS_P(NODE) \
163 (BINDING_VECTOR_CHECK (NODE)->base.static_flag)
164 /* This binding contains duplicate references to a partioned module
165 entity. */
166 #define BINDING_VECTOR_PARTITION_DUPS_P(NODE) \
167 (BINDING_VECTOR_CHECK (NODE)->base.volatile_flag)
168
169 /* These two flags indicate the provenence of the bindings on this
170 particular vector slot. We can of course determine this from slot
171 number, but that's a relatively expensive lookup. This avoids
172 that when iterating. */
173 /* This slot is part of the global module (a header unit). */
174 #define MODULE_BINDING_GLOBAL_P(NODE) \
175 (OVERLOAD_CHECK (NODE)->base.static_flag)
176 /* This slot is part of the current module (a partition or primary). */
177 #define MODULE_BINDING_PARTITION_P(NODE) \
178 (OVERLOAD_CHECK (NODE)->base.volatile_flag)
179
180 extern void set_identifier_type_value (tree, tree);
181 extern void push_binding (tree, tree, cp_binding_level*);
182 extern void pop_local_binding (tree, tree);
183 extern void pop_bindings_and_leave_scope (void);
184 extern tree constructor_name (tree);
185 extern bool constructor_name_p (tree, tree);
186
187 /* The kinds of scopes we recognize. */
188 enum scope_kind {
189 sk_block = 0, /* An ordinary block scope. This enumerator must
190 have the value zero because "cp_binding_level"
191 is initialized by using "memset" to set the
192 contents to zero, and the default scope kind
193 is "sk_block". */
194 sk_cleanup, /* A scope for (pseudo-)scope for cleanup. It is
195 pseudo in that it is transparent to name lookup
196 activities. */
197 sk_try, /* A try-block. */
198 sk_catch, /* A catch-block. */
199 sk_for, /* The scope of the variable declared in a
200 init-statement. */
201 sk_cond, /* The scope of the variable declared in the condition
202 of an if or switch statement. */
203 sk_stmt_expr, /* GNU statement expression block. */
204 sk_function_parms, /* The scope containing function parameters. */
205 sk_class, /* The scope containing the members of a class. */
206 sk_scoped_enum, /* The scope containing the enumerators of a C++11
207 scoped enumeration. */
208 sk_namespace, /* The scope containing the members of a
209 namespace, including the global scope. */
210 sk_template_parms, /* A scope for template parameters. */
211 sk_template_spec, /* Like sk_template_parms, but for an explicit
212 specialization. Since, by definition, an
213 explicit specialization is introduced by
214 "template <>", this scope is always empty. */
215 sk_transaction, /* A synchronized or atomic statement. */
216 sk_omp /* An OpenMP structured block. */
217 };
218
219 struct GTY(()) cp_class_binding {
220 cxx_binding *base;
221 /* The bound name. */
222 tree identifier;
223 };
224
225 /* For each binding contour we allocate a binding_level structure
226 which records the names defined in that contour.
227 Contours include:
228 0) the global one
229 1) one for each function definition,
230 where internal declarations of the parameters appear.
231 2) one for each compound statement,
232 to record its declarations.
233
234 The current meaning of a name can be found by searching the levels
235 from the current one out to the global one.
236
237 Off to the side, may be the class_binding_level. This exists only
238 to catch class-local declarations. It is otherwise nonexistent.
239
240 Also there may be binding levels that catch cleanups that must be
241 run when exceptions occur. Thus, to see whether a name is bound in
242 the current scope, it is not enough to look in the
243 CURRENT_BINDING_LEVEL. You should use lookup_name_current_level
244 instead. */
245
246 struct GTY(()) cp_binding_level {
247 /* A chain of _DECL nodes for all variables, constants, functions,
248 and typedef types. These are in the reverse of the order
249 supplied. There may be OVERLOADs on this list, too, but they
250 are wrapped in TREE_LISTs; the TREE_VALUE is the OVERLOAD. */
251 tree names;
252
253 /* Using directives. */
254 vec<tree, va_gc> *using_directives;
255
256 /* For the binding level corresponding to a class, the entities
257 declared in the class or its base classes. */
258 vec<cp_class_binding, va_gc> *class_shadowed;
259
260 /* Similar to class_shadowed, but for IDENTIFIER_TYPE_VALUE, and
261 is used for all binding levels. The TREE_PURPOSE is the name of
262 the entity, the TREE_TYPE is the associated type. In addition
263 the TREE_VALUE is the IDENTIFIER_TYPE_VALUE before we entered
264 the class. */
265 tree type_shadowed;
266
267 /* For each level (except not the global one),
268 a chain of BLOCK nodes for all the levels
269 that were entered and exited one level down. */
270 tree blocks;
271
272 /* The entity (namespace, class, function) the scope of which this
273 binding contour corresponds to. Otherwise NULL. */
274 tree this_entity;
275
276 /* The binding level which this one is contained in (inherits from). */
277 cp_binding_level *level_chain;
278
279 /* STATEMENT_LIST for statements in this binding contour.
280 Only used at present for SK_CLEANUP temporary bindings. */
281 tree statement_list;
282
283 /* Binding depth at which this level began. */
284 int binding_depth;
285
286 /* The kind of scope that this object represents. However, a
287 SK_TEMPLATE_SPEC scope is represented with KIND set to
288 SK_TEMPLATE_PARMS and EXPLICIT_SPEC_P set to true. */
289 ENUM_BITFIELD (scope_kind) kind : 4;
290
291 /* True if this scope is an SK_TEMPLATE_SPEC scope. This field is
292 only valid if KIND == SK_TEMPLATE_PARMS. */
293 BOOL_BITFIELD explicit_spec_p : 1;
294
295 /* true means make a BLOCK for this level regardless of all else. */
296 unsigned keep : 1;
297
298 /* Nonzero if this level can safely have additional
299 cleanup-needing variables added to it. */
300 unsigned more_cleanups_ok : 1;
301 unsigned have_cleanups : 1;
302
303 /* Transient state set if this scope is of sk_class kind
304 and is in the process of defining 'this_entity'. Reset
305 on leaving the class definition to allow for the scope
306 to be subsequently re-used as a non-defining scope for
307 'this_entity'. */
308 unsigned defining_class_p : 1;
309
310 /* True for SK_FUNCTION_PARMS of a requires-expression. */
311 unsigned requires_expression: 1;
312
313 /* 22 bits left to fill a 32-bit word. */
314 };
315
316 /* The binding level currently in effect. */
317
318 #define current_binding_level \
319 (*(cfun && cp_function_chain && cp_function_chain->bindings \
320 ? &cp_function_chain->bindings \
321 : &scope_chain->bindings))
322
323 /* The binding level of the current class, if any. */
324
325 #define class_binding_level scope_chain->class_bindings
326
327 /* True if SCOPE designates the global scope binding contour. */
328 #define global_scope_p(SCOPE) \
329 ((SCOPE) == NAMESPACE_LEVEL (global_namespace))
330
331 extern cp_binding_level *leave_scope (void);
332 extern bool kept_level_p (void);
333 extern bool global_bindings_p (void);
334 extern bool toplevel_bindings_p (void);
335 extern bool namespace_bindings_p (void);
336 extern bool local_bindings_p (void);
337 extern bool template_parm_scope_p (void);
338 extern scope_kind innermost_scope_kind (void);
339 extern cp_binding_level *begin_scope (scope_kind, tree);
340 extern void print_binding_stack (void);
341 extern void pop_everything (void);
342 extern void keep_next_level (bool);
343 extern bool is_ancestor (tree ancestor, tree descendant);
344 extern bool is_nested_namespace (tree parent, tree descendant,
345 bool inline_only = false);
346 extern tree push_scope (tree);
347 extern void pop_scope (tree);
348 extern tree push_inner_scope (tree);
349 extern void pop_inner_scope (tree, tree);
350 extern void push_binding_level (cp_binding_level *);
351
352 extern bool handle_namespace_attrs (tree, tree);
353 extern void pushlevel_class (void);
354 extern void poplevel_class (void);
355
356 /* What kind of scopes name lookup looks in. An enum class so we
357 don't accidentally mix integers. */
358 enum class LOOK_where
359 {
360 BLOCK = 1 << 0, /* Consider block scopes. */
361 CLASS = 1 << 1, /* Consider class scopes. */
362 NAMESPACE = 1 << 2, /* Consider namespace scopes. */
363
364 ALL = BLOCK | CLASS | NAMESPACE,
365 BLOCK_NAMESPACE = BLOCK | NAMESPACE,
366 CLASS_NAMESPACE = CLASS | NAMESPACE,
367 };
368 constexpr LOOK_where operator| (LOOK_where a, LOOK_where b)
369 {
370 return LOOK_where (unsigned (a) | unsigned (b));
371 }
372 constexpr LOOK_where operator& (LOOK_where a, LOOK_where b)
373 {
374 return LOOK_where (unsigned (a) & unsigned (b));
375 }
376
377 enum class LOOK_want
378 {
379 NORMAL = 0, /* Normal lookup -- non-types can hide implicit types. */
380 TYPE = 1 << 1, /* We only want TYPE_DECLS. */
381 NAMESPACE = 1 << 2, /* We only want NAMESPACE_DECLS. */
382
383 HIDDEN_FRIEND = 1 << 3, /* See hidden friends. */
384 HIDDEN_LAMBDA = 1 << 4, /* See lambda-ignored entities. */
385
386 TYPE_NAMESPACE = TYPE | NAMESPACE, /* Either NAMESPACE or TYPE. */
387 };
388 constexpr LOOK_want operator| (LOOK_want a, LOOK_want b)
389 {
390 return LOOK_want (unsigned (a) | unsigned (b));
391 }
392 constexpr LOOK_want operator& (LOOK_want a, LOOK_want b)
393 {
394 return LOOK_want (unsigned (a) & unsigned (b));
395 }
396
397 extern tree lookup_name (tree, LOOK_where, LOOK_want = LOOK_want::NORMAL);
398 /* Also declared in c-family/c-common.h. */
399 extern tree lookup_name (tree name);
400 inline tree lookup_name (tree name, LOOK_want want)
401 {
402 return lookup_name (name, LOOK_where::ALL, want);
403 }
404
405 enum class TAG_how
406 {
407 CURRENT_ONLY = 0, // Look and insert only in current scope
408
409 GLOBAL = 1, // Unqualified lookup, innermost-non-class insertion
410
411 INNERMOST_NON_CLASS = 2, // Look and insert only into
412 // innermost-non-class
413
414 HIDDEN_FRIEND = 3, // As INNERMOST_NON_CLASS, but hide it
415 };
416
417 extern tree lookup_elaborated_type (tree, TAG_how);
418 extern tree get_namespace_binding (tree ns, tree id);
419 extern void set_global_binding (tree decl);
420 inline tree get_global_binding (tree id)
421 {
422 return get_namespace_binding (NULL_TREE, id);
423 }
424 extern tree lookup_qualified_name (tree scope, tree name,
425 LOOK_want = LOOK_want::NORMAL,
426 bool = true);
427 extern tree lookup_qualified_name (tree scope, const char *name,
428 LOOK_want = LOOK_want::NORMAL,
429 bool = true);
430 extern bool pushdecl_class_level (tree);
431 extern tree pushdecl_namespace_level (tree, bool hiding = false);
432 extern bool push_class_level_binding (tree, tree);
433 extern tree get_local_decls ();
434 extern int function_parm_depth (void);
435 extern tree cp_namespace_decls (tree);
436 extern void set_decl_namespace (tree, tree, bool);
437 extern void push_decl_namespace (tree);
438 extern void pop_decl_namespace (void);
439 extern void do_namespace_alias (tree, tree);
440 extern tree do_class_using_decl (tree, tree);
441 extern tree lookup_arg_dependent (tree, tree, vec<tree, va_gc> *);
442 extern tree search_anon_aggr (tree, tree, bool = false);
443 extern tree get_class_binding_direct (tree, tree, bool want_type = false);
444 extern tree get_class_binding (tree, tree, bool want_type = false);
445 extern tree *find_member_slot (tree klass, tree name);
446 extern tree *add_member_slot (tree klass, tree name);
447 extern void resort_type_member_vec (void *, void *,
448 gt_pointer_operator, void *);
449 extern vec<tree, va_gc> *set_class_bindings (tree, int extra = 0);
450 extern void insert_late_enum_def_bindings (tree, tree);
451 extern tree innermost_non_namespace_value (tree);
452 extern cxx_binding *outer_binding (tree, cxx_binding *, bool);
453 extern void cp_emit_debug_info_for_using (tree, tree);
454
455 extern void finish_nonmember_using_decl (tree scope, tree name);
456 extern void finish_using_directive (tree target, tree attribs);
457 void push_local_extern_decl_alias (tree decl);
458 extern tree pushdecl (tree, bool hiding = false);
459 extern tree pushdecl_outermost_localscope (tree);
460 extern tree pushdecl_top_level (tree);
461 extern tree pushdecl_top_level_and_finish (tree, tree);
462 extern tree pushtag (tree, tree, TAG_how = TAG_how::CURRENT_ONLY);
463 extern int push_namespace (tree, bool make_inline = false);
464 extern void pop_namespace (void);
465 extern void push_nested_namespace (tree);
466 extern void pop_nested_namespace (tree);
467 extern void push_to_top_level (void);
468 extern void pop_from_top_level (void);
469 extern bool maybe_push_to_top_level (tree);
470 extern void maybe_pop_from_top_level (bool);
471 extern void push_using_decl_bindings (tree, tree);
472
473 /* Lower level interface for modules. */
474 extern tree *mergeable_namespace_slots (tree ns, tree name, bool is_attached,
475 tree *mvec);
476 extern void add_mergeable_namespace_entity (tree *slot, tree decl);
477 extern tree lookup_class_binding (tree ctx, tree name);
478 extern bool import_module_binding (tree ctx, tree name, unsigned mod,
479 unsigned snum);
480 extern bool set_module_binding (tree ctx, tree name, unsigned mod,
481 int mod_glob_flag,
482 tree value, tree type, tree visible);
483 extern void add_module_namespace_decl (tree ns, tree decl);
484
485 enum WMB_Flags
486 {
487 WMB_None = 0,
488 WMB_Dups = 1 << 0,
489 WMB_Export = 1 << 1,
490 WMB_Using = 1 << 2,
491 WMB_Hidden = 1 << 3,
492 };
493
494 extern unsigned walk_module_binding (tree binding, bitmap partitions,
495 bool (*)(tree decl, WMB_Flags, void *data),
496 void *data);
497 extern tree add_imported_namespace (tree ctx, tree name, location_t,
498 unsigned module,
499 bool inline_p, bool visible_p);
500 extern const char *get_cxx_dialect_name (enum cxx_dialect dialect);
501
502 #endif /* GCC_CP_NAME_LOOKUP_H */