1 /* Declarations for -*- C++ -*- name lookup routines.
2 Copyright (C) 2003-2021 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.c. */
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 }
is_lazybinding_slot92 bool is_lazy () const
93 {
94 return bool (uintptr_t (u.binding) & 1);
95 }
set_lazybinding_slot96 void set_lazy (unsigned snum)
97 {
98 gcc_checking_assert (!u.binding);
99 u.binding = tree (uintptr_t ((snum << 1) | 1));
100 }
or_lazybinding_slot101 void or_lazy (unsigned snum)
102 {
103 gcc_checking_assert (is_lazy ());
104 u.binding = tree (uintptr_t (u.binding) | (snum << 1));
105 }
get_lazybinding_slot106 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_function_parms, /* The scope containing function parameters. */
204 sk_class, /* The scope containing the members of a class. */
205 sk_scoped_enum, /* The scope containing the enumerators of a C++11
206 scoped enumeration. */
207 sk_namespace, /* The scope containing the members of a
208 namespace, including the global scope. */
209 sk_template_parms, /* A scope for template parameters. */
210 sk_template_spec, /* Like sk_template_parms, but for an explicit
211 specialization. Since, by definition, an
212 explicit specialization is introduced by
213 "template <>", this scope is always empty. */
214 sk_transaction, /* A synchronized or atomic statement. */
215 sk_omp /* An OpenMP structured block. */
216 };
217
218 struct GTY(()) cp_class_binding {
219 cxx_binding *base;
220 /* The bound name. */
221 tree identifier;
222 };
223
224 /* For each binding contour we allocate a binding_level structure
225 which records the names defined in that contour.
226 Contours include:
227 0) the global one
228 1) one for each function definition,
229 where internal declarations of the parameters appear.
230 2) one for each compound statement,
231 to record its declarations.
232
233 The current meaning of a name can be found by searching the levels
234 from the current one out to the global one.
235
236 Off to the side, may be the class_binding_level. This exists only
237 to catch class-local declarations. It is otherwise nonexistent.
238
239 Also there may be binding levels that catch cleanups that must be
240 run when exceptions occur. Thus, to see whether a name is bound in
241 the current scope, it is not enough to look in the
242 CURRENT_BINDING_LEVEL. You should use lookup_name_current_level
243 instead. */
244
245 struct GTY(()) cp_binding_level {
246 /* A chain of _DECL nodes for all variables, constants, functions,
247 and typedef types. These are in the reverse of the order
248 supplied. There may be OVERLOADs on this list, too, but they
249 are wrapped in TREE_LISTs; the TREE_VALUE is the OVERLOAD. */
250 tree names;
251
252 /* Using directives. */
253 vec<tree, va_gc> *using_directives;
254
255 /* For the binding level corresponding to a class, the entities
256 declared in the class or its base classes. */
257 vec<cp_class_binding, va_gc> *class_shadowed;
258
259 /* Similar to class_shadowed, but for IDENTIFIER_TYPE_VALUE, and
260 is used for all binding levels. The TREE_PURPOSE is the name of
261 the entity, the TREE_TYPE is the associated type. In addition
262 the TREE_VALUE is the IDENTIFIER_TYPE_VALUE before we entered
263 the class. */
264 tree type_shadowed;
265
266 /* For each level (except not the global one),
267 a chain of BLOCK nodes for all the levels
268 that were entered and exited one level down. */
269 tree blocks;
270
271 /* The entity (namespace, class, function) the scope of which this
272 binding contour corresponds to. Otherwise NULL. */
273 tree this_entity;
274
275 /* The binding level which this one is contained in (inherits from). */
276 cp_binding_level *level_chain;
277
278 /* STATEMENT_LIST for statements in this binding contour.
279 Only used at present for SK_CLEANUP temporary bindings. */
280 tree statement_list;
281
282 /* Binding depth at which this level began. */
283 int binding_depth;
284
285 /* The kind of scope that this object represents. However, a
286 SK_TEMPLATE_SPEC scope is represented with KIND set to
287 SK_TEMPLATE_PARMS and EXPLICIT_SPEC_P set to true. */
288 ENUM_BITFIELD (scope_kind) kind : 4;
289
290 /* True if this scope is an SK_TEMPLATE_SPEC scope. This field is
291 only valid if KIND == SK_TEMPLATE_PARMS. */
292 BOOL_BITFIELD explicit_spec_p : 1;
293
294 /* true means make a BLOCK for this level regardless of all else. */
295 unsigned keep : 1;
296
297 /* Nonzero if this level can safely have additional
298 cleanup-needing variables added to it. */
299 unsigned more_cleanups_ok : 1;
300 unsigned have_cleanups : 1;
301
302 /* Transient state set if this scope is of sk_class kind
303 and is in the process of defining 'this_entity'. Reset
304 on leaving the class definition to allow for the scope
305 to be subsequently re-used as a non-defining scope for
306 'this_entity'. */
307 unsigned defining_class_p : 1;
308
309 /* true for SK_FUNCTION_PARMS of immediate functions. */
310 unsigned immediate_fn_ctx_p : 1;
311
312 /* 22 bits left to fill a 32-bit word. */
313 };
314
315 /* The binding level currently in effect. */
316
317 #define current_binding_level \
318 (*(cfun && cp_function_chain && cp_function_chain->bindings \
319 ? &cp_function_chain->bindings \
320 : &scope_chain->bindings))
321
322 /* The binding level of the current class, if any. */
323
324 #define class_binding_level scope_chain->class_bindings
325
326 /* True if SCOPE designates the global scope binding contour. */
327 #define global_scope_p(SCOPE) \
328 ((SCOPE) == NAMESPACE_LEVEL (global_namespace))
329
330 extern cp_binding_level *leave_scope (void);
331 extern bool kept_level_p (void);
332 extern bool global_bindings_p (void);
333 extern bool toplevel_bindings_p (void);
334 extern bool namespace_bindings_p (void);
335 extern bool local_bindings_p (void);
336 extern bool template_parm_scope_p (void);
337 extern scope_kind innermost_scope_kind (void);
338 extern cp_binding_level *begin_scope (scope_kind, tree);
339 extern void print_binding_stack (void);
340 extern void pop_everything (void);
341 extern void keep_next_level (bool);
342 extern bool is_ancestor (tree ancestor, tree descendant);
343 extern bool is_nested_namespace (tree parent, tree descendant,
344 bool inline_only = false);
345 extern tree push_scope (tree);
346 extern void pop_scope (tree);
347 extern tree push_inner_scope (tree);
348 extern void pop_inner_scope (tree, tree);
349 extern void push_binding_level (cp_binding_level *);
350
351 extern bool handle_namespace_attrs (tree, tree);
352 extern void pushlevel_class (void);
353 extern void poplevel_class (void);
354
355 /* What kind of scopes name lookup looks in. An enum class so we
356 don't accidentally mix integers. */
357 enum class LOOK_where
358 {
359 BLOCK = 1 << 0, /* Consider block scopes. */
360 CLASS = 1 << 1, /* Consider class scopes. */
361 NAMESPACE = 1 << 2, /* Consider namespace scopes. */
362
363 ALL = BLOCK | CLASS | NAMESPACE,
364 BLOCK_NAMESPACE = BLOCK | NAMESPACE,
365 CLASS_NAMESPACE = CLASS | NAMESPACE,
366 };
367 constexpr LOOK_where operator| (LOOK_where a, LOOK_where b)
368 {
369 return LOOK_where (unsigned (a) | unsigned (b));
370 }
371 constexpr LOOK_where operator& (LOOK_where a, LOOK_where b)
372 {
373 return LOOK_where (unsigned (a) & unsigned (b));
374 }
375
376 enum class LOOK_want
377 {
378 NORMAL = 0, /* Normal lookup -- non-types can hide implicit types. */
379 TYPE = 1 << 1, /* We only want TYPE_DECLS. */
380 NAMESPACE = 1 << 2, /* We only want NAMESPACE_DECLS. */
381
382 HIDDEN_FRIEND = 1 << 3, /* See hidden friends. */
383 HIDDEN_LAMBDA = 1 << 4, /* See lambda-ignored entities. */
384
385 TYPE_NAMESPACE = TYPE | NAMESPACE, /* Either NAMESPACE or TYPE. */
386 };
387 constexpr LOOK_want operator| (LOOK_want a, LOOK_want b)
388 {
389 return LOOK_want (unsigned (a) | unsigned (b));
390 }
391 constexpr LOOK_want operator& (LOOK_want a, LOOK_want b)
392 {
393 return LOOK_want (unsigned (a) & unsigned (b));
394 }
395
396 extern tree lookup_name (tree, LOOK_where, LOOK_want = LOOK_want::NORMAL);
397 /* Also declared in c-family/c-common.h. */
398 extern tree lookup_name (tree name);
lookup_name(tree name,LOOK_want want)399 inline tree lookup_name (tree name, LOOK_want want)
400 {
401 return lookup_name (name, LOOK_where::ALL, want);
402 }
403
404 enum class TAG_how
405 {
406 CURRENT_ONLY = 0, // Look and insert only in current scope
407
408 GLOBAL = 1, // Unqualified lookup, innermost-non-class insertion
409
410 INNERMOST_NON_CLASS = 2, // Look and insert only into
411 // innermost-non-class
412
413 HIDDEN_FRIEND = 3, // As INNERMOST_NON_CLASS, but hide it
414 };
415
416 extern tree lookup_elaborated_type (tree, TAG_how);
417 extern tree get_namespace_binding (tree ns, tree id);
418 extern void set_global_binding (tree decl);
get_global_binding(tree id)419 inline tree get_global_binding (tree id)
420 {
421 return get_namespace_binding (NULL_TREE, id);
422 }
423 extern tree lookup_qualified_name (tree scope, tree name,
424 LOOK_want = LOOK_want::NORMAL,
425 bool = true);
426 extern tree lookup_qualified_name (tree scope, const char *name,
427 LOOK_want = LOOK_want::NORMAL,
428 bool = true);
429 extern bool pushdecl_class_level (tree);
430 extern tree pushdecl_namespace_level (tree, bool hiding = false);
431 extern bool push_class_level_binding (tree, tree);
432 extern tree get_local_decls ();
433 extern int function_parm_depth (void);
434 extern tree cp_namespace_decls (tree);
435 extern void set_decl_namespace (tree, tree, bool);
436 extern void push_decl_namespace (tree);
437 extern void pop_decl_namespace (void);
438 extern void do_namespace_alias (tree, tree);
439 extern tree do_class_using_decl (tree, tree);
440 extern tree lookup_arg_dependent (tree, tree, vec<tree, va_gc> *);
441 extern tree search_anon_aggr (tree, tree, bool = false);
442 extern tree get_class_binding_direct (tree, tree, bool want_type = false);
443 extern tree get_class_binding (tree, tree, bool want_type = false);
444 extern tree *find_member_slot (tree klass, tree name);
445 extern tree *add_member_slot (tree klass, tree name);
446 extern void resort_type_member_vec (void *, void *,
447 gt_pointer_operator, void *);
448 extern vec<tree, va_gc> *set_class_bindings (tree, int extra = 0);
449 extern void insert_late_enum_def_bindings (tree, tree);
450 extern tree innermost_non_namespace_value (tree);
451 extern cxx_binding *outer_binding (tree, cxx_binding *, bool);
452 extern void cp_emit_debug_info_for_using (tree, tree);
453
454 extern void finish_nonmember_using_decl (tree scope, tree name);
455 extern void finish_using_directive (tree target, tree attribs);
456 void push_local_extern_decl_alias (tree decl);
457 extern tree pushdecl (tree, bool hiding = false);
458 extern tree pushdecl_outermost_localscope (tree);
459 extern tree pushdecl_top_level (tree);
460 extern tree pushdecl_top_level_and_finish (tree, tree);
461 extern tree pushtag (tree, tree, TAG_how = TAG_how::CURRENT_ONLY);
462 extern int push_namespace (tree, bool make_inline = false);
463 extern void pop_namespace (void);
464 extern void push_nested_namespace (tree);
465 extern void pop_nested_namespace (tree);
466 extern void push_to_top_level (void);
467 extern void pop_from_top_level (void);
468 extern void maybe_save_operator_binding (tree);
469 extern void push_operator_bindings (void);
470 extern void push_using_decl_bindings (tree, tree);
471 extern void discard_operator_bindings (tree);
472
473 /* Lower level interface for modules. */
474 extern tree *mergeable_namespace_slots (tree ns, tree name, bool is_global,
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 */
503