1/* Declarations for C++ name lookup routines.
2   Copyright (C) 2003-2015 Free Software Foundation, Inc.
3   Contributed by Gabriel Dos Reis <gdr@integrable-solutions.net>
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify
8it under the terms of the GNU General Public License as published by
9the Free Software Foundation; either version 3, or (at your option)
10any later version.
11
12GCC is distributed in the hope that it will be useful,
13but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15GNU General Public License for more details.
16
17You should have received a copy of the GNU General Public License
18along 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/* The type of dictionary used to map names to types declared at
27   a given scope.  */
28typedef struct binding_table_s *binding_table;
29typedef struct binding_entry_s *binding_entry;
30
31/* The type of a routine repeatedly called by binding_table_foreach.  */
32typedef void (*bt_foreach_proc) (binding_entry, void *);
33
34struct GTY(()) binding_entry_s {
35  binding_entry chain;
36  tree name;
37  tree type;
38};
39
40/* These macros indicate the initial chains count for binding_table.  */
41#define SCOPE_DEFAULT_HT_SIZE		(1 << 3)
42#define CLASS_SCOPE_HT_SIZE		(1 << 3)
43#define NAMESPACE_ORDINARY_HT_SIZE	(1 << 5)
44#define NAMESPACE_STD_HT_SIZE		(1 << 8)
45#define GLOBAL_SCOPE_HT_SIZE		(1 << 8)
46
47extern void binding_table_foreach (binding_table, bt_foreach_proc, void *);
48extern binding_entry binding_table_find (binding_table, tree);
49
50/* Datatype that represents binding established by a declaration between
51   a name and a C++ entity.  */
52typedef struct cxx_binding cxx_binding;
53
54/* The datatype used to implement C++ scope.  */
55typedef struct cp_binding_level cp_binding_level;
56
57/* Nonzero if this binding is for a local scope, as opposed to a class
58   or namespace scope.  */
59#define LOCAL_BINDING_P(NODE) ((NODE)->is_local)
60
61/* True if NODE->value is from a base class of the class which is
62   currently being defined.  */
63#define INHERITED_VALUE_BINDING_P(NODE) ((NODE)->value_is_inherited)
64
65struct GTY(()) cxx_binding {
66  /* Link to chain together various bindings for this name.  */
67  cxx_binding *previous;
68  /* The non-type entity this name is bound to.  */
69  tree value;
70  /* The type entity this name is bound to.  */
71  tree type;
72  /* The scope at which this binding was made.  */
73  cp_binding_level *scope;
74  unsigned value_is_inherited : 1;
75  unsigned is_local : 1;
76};
77
78/* Datatype used to temporarily save C++ bindings (for implicit
79   instantiations purposes and like).  Implemented in decl.c.  */
80typedef struct GTY(()) cxx_saved_binding {
81  /* The name of the current binding.  */
82  tree identifier;
83  /* The binding we're saving.  */
84  cxx_binding *binding;
85  tree real_type_value;
86} cxx_saved_binding;
87
88
89extern tree identifier_type_value (tree);
90extern void set_identifier_type_value (tree, tree);
91extern void pop_binding (tree, tree);
92extern void pop_bindings_and_leave_scope (void);
93extern tree constructor_name (tree);
94extern bool constructor_name_p (tree, tree);
95
96/* The kinds of scopes we recognize.  */
97typedef enum scope_kind {
98  sk_block = 0,      /* An ordinary block scope.  This enumerator must
99			have the value zero because "cp_binding_level"
100			is initialized by using "memset" to set the
101			contents to zero, and the default scope kind
102			is "sk_block".  */
103  sk_cleanup,	     /* A scope for (pseudo-)scope for cleanup.  It is
104			pseudo in that it is transparent to name lookup
105			activities.  */
106  sk_try,	     /* A try-block.  */
107  sk_catch,	     /* A catch-block.  */
108  sk_for,	     /* The scope of the variable declared in a
109			for-init-statement.  */
110  sk_cond,	     /* The scope of the variable declared in the condition
111			of an if or switch statement.  */
112  sk_function_parms, /* The scope containing function parameters.  */
113  sk_class,	     /* The scope containing the members of a class.  */
114  sk_scoped_enum,    /* The scope containing the enumertors of a C++0x
115                        scoped enumeration.  */
116  sk_namespace,	     /* The scope containing the members of a
117			namespace, including the global scope.  */
118  sk_template_parms, /* A scope for template parameters.  */
119  sk_template_spec,  /* Like sk_template_parms, but for an explicit
120			specialization.  Since, by definition, an
121			explicit specialization is introduced by
122			"template <>", this scope is always empty.  */
123  sk_omp	     /* An OpenMP structured block.  */
124} scope_kind;
125
126/* The scope where the class/struct/union/enum tag applies.  */
127typedef enum tag_scope {
128  ts_current = 0,	/* Current scope only.  This is for the
129			     class-key identifier;
130			   case mentioned in [basic.lookup.elab]/2,
131			   or the class/enum definition
132			     class-key identifier { ... };  */
133  ts_global = 1,	/* All scopes.  This is the 3.4.1
134			   [basic.lookup.unqual] lookup mentioned
135			   in [basic.lookup.elab]/2.  */
136  ts_within_enclosing_non_class = 2,	/* Search within enclosing non-class
137					   only, for friend class lookup
138					   according to [namespace.memdef]/3
139					   and [class.friend]/9.  */
140  ts_lambda = 3			/* Declaring a lambda closure.  */
141} tag_scope;
142
143typedef struct GTY(()) cp_class_binding {
144  cxx_binding *base;
145  /* The bound name.  */
146  tree identifier;
147} cp_class_binding;
148
149
150typedef struct GTY(()) cp_label_binding {
151  /* The bound LABEL_DECL.  */
152  tree label;
153  /* The previous IDENTIFIER_LABEL_VALUE.  */
154  tree prev_value;
155} cp_label_binding;
156
157
158/* For each binding contour we allocate a binding_level structure
159   which records the names defined in that contour.
160   Contours include:
161    0) the global one
162    1) one for each function definition,
163       where internal declarations of the parameters appear.
164    2) one for each compound statement,
165       to record its declarations.
166
167   The current meaning of a name can be found by searching the levels
168   from the current one out to the global one.
169
170   Off to the side, may be the class_binding_level.  This exists only
171   to catch class-local declarations.  It is otherwise nonexistent.
172
173   Also there may be binding levels that catch cleanups that must be
174   run when exceptions occur.  Thus, to see whether a name is bound in
175   the current scope, it is not enough to look in the
176   CURRENT_BINDING_LEVEL.  You should use lookup_name_current_level
177   instead.  */
178
179/* Note that the information in the `names' component of the global contour
180   is duplicated in the IDENTIFIER_GLOBAL_VALUEs of all identifiers.  */
181
182struct GTY(()) cp_binding_level {
183  /* A chain of _DECL nodes for all variables, constants, functions,
184      and typedef types.  These are in the reverse of the order
185      supplied.  There may be OVERLOADs on this list, too, but they
186      are wrapped in TREE_LISTs; the TREE_VALUE is the OVERLOAD.  */
187  tree names;
188
189  /* A chain of NAMESPACE_DECL nodes.  */
190  tree namespaces;
191
192  /* An array of static functions and variables (for namespaces only) */
193  vec<tree, va_gc> *static_decls;
194
195  /* A list of USING_DECL nodes.  */
196  tree usings;
197
198  /* A list of used namespaces. PURPOSE is the namespace,
199      VALUE the common ancestor with this binding_level's namespace.  */
200  tree using_directives;
201
202  /* For the binding level corresponding to a class, the entities
203      declared in the class or its base classes.  */
204  vec<cp_class_binding, va_gc> *class_shadowed;
205
206  /* Similar to class_shadowed, but for IDENTIFIER_TYPE_VALUE, and
207      is used for all binding levels. The TREE_PURPOSE is the name of
208      the entity, the TREE_TYPE is the associated type.  In addition
209      the TREE_VALUE is the IDENTIFIER_TYPE_VALUE before we entered
210      the class.  */
211  tree type_shadowed;
212
213  /* Similar to class_shadowed, but for IDENTIFIER_LABEL_VALUE, and
214      used for all binding levels.  */
215  vec<cp_label_binding, va_gc> *shadowed_labels;
216
217  /* For each level (except not the global one),
218      a chain of BLOCK nodes for all the levels
219      that were entered and exited one level down.  */
220  tree blocks;
221
222  /* The entity (namespace, class, function) the scope of which this
223      binding contour corresponds to.  Otherwise NULL.  */
224  tree this_entity;
225
226  /* The binding level which this one is contained in (inherits from).  */
227  cp_binding_level *level_chain;
228
229  /* List of VAR_DECLS saved from a previous for statement.
230      These would be dead in ISO-conforming code, but might
231      be referenced in ARM-era code.  */
232  vec<tree, va_gc> *dead_vars_from_for;
233
234  /* STATEMENT_LIST for statements in this binding contour.
235      Only used at present for SK_CLEANUP temporary bindings.  */
236  tree statement_list;
237
238  /* Binding depth at which this level began.  */
239  int binding_depth;
240
241  /* The kind of scope that this object represents.  However, a
242      SK_TEMPLATE_SPEC scope is represented with KIND set to
243      SK_TEMPLATE_PARMS and EXPLICIT_SPEC_P set to true.  */
244  ENUM_BITFIELD (scope_kind) kind : 4;
245
246  /* True if this scope is an SK_TEMPLATE_SPEC scope.  This field is
247      only valid if KIND == SK_TEMPLATE_PARMS.  */
248  BOOL_BITFIELD explicit_spec_p : 1;
249
250  /* true means make a BLOCK for this level regardless of all else.  */
251  unsigned keep : 1;
252
253  /* Nonzero if this level can safely have additional
254      cleanup-needing variables added to it.  */
255  unsigned more_cleanups_ok : 1;
256  unsigned have_cleanups : 1;
257
258  /* Transient state set if this scope is of sk_class kind
259     and is in the process of defining 'this_entity'.  Reset
260     on leaving the class definition to allow for the scope
261     to be subsequently re-used as a non-defining scope for
262     'this_entity'.  */
263  unsigned defining_class_p : 1;
264
265  /* 23 bits left to fill a 32-bit word.  */
266};
267
268/* The binding level currently in effect.  */
269
270#define current_binding_level			\
271  (*(cfun && cp_function_chain && cp_function_chain->bindings \
272   ? &cp_function_chain->bindings		\
273   : &scope_chain->bindings))
274
275/* The binding level of the current class, if any.  */
276
277#define class_binding_level scope_chain->class_bindings
278
279/* The tree node representing the global scope.  */
280extern GTY(()) tree global_namespace;
281extern GTY(()) tree global_scope_name;
282
283/* Indicates that there is a type value in some namespace, although
284   that is not necessarily in scope at the moment.  */
285
286extern GTY(()) tree global_type_node;
287
288/* True if SCOPE designates the global scope binding contour.  */
289#define global_scope_p(SCOPE) \
290  ((SCOPE) == NAMESPACE_LEVEL (global_namespace))
291
292extern cp_binding_level *leave_scope (void);
293extern bool kept_level_p (void);
294extern bool global_bindings_p (void);
295extern bool toplevel_bindings_p	(void);
296extern bool namespace_bindings_p (void);
297extern bool local_bindings_p (void);
298extern bool template_parm_scope_p (void);
299extern scope_kind innermost_scope_kind (void);
300extern cp_binding_level *begin_scope (scope_kind, tree);
301extern void print_binding_stack	(void);
302extern void push_to_top_level (void);
303extern void pop_from_top_level (void);
304extern void pop_everything (void);
305extern void keep_next_level (bool);
306extern bool is_ancestor (tree, tree);
307extern tree push_scope (tree);
308extern void pop_scope (tree);
309extern tree push_inner_scope (tree);
310extern void pop_inner_scope (tree, tree);
311extern void push_binding_level (cp_binding_level *);
312
313extern void push_namespace (tree);
314extern void pop_namespace (void);
315extern void push_nested_namespace (tree);
316extern void pop_nested_namespace (tree);
317extern bool handle_namespace_attrs (tree, tree);
318extern void pushlevel_class (void);
319extern void poplevel_class (void);
320extern tree pushdecl_with_scope (tree, cp_binding_level *, bool);
321extern tree lookup_name_prefer_type (tree, int);
322extern tree lookup_name_real (tree, int, int, bool, int, int);
323extern tree lookup_type_scope (tree, tag_scope);
324extern tree namespace_binding (tree, tree);
325extern void set_namespace_binding (tree, tree, tree);
326extern bool hidden_name_p (tree);
327extern tree remove_hidden_names (tree);
328extern tree lookup_qualified_name (tree, tree, bool, bool);
329extern tree lookup_name_nonclass (tree);
330extern tree lookup_name_innermost_nonclass_level (tree);
331extern bool is_local_extern (tree);
332extern tree lookup_function_nonclass (tree, vec<tree, va_gc> *, bool);
333extern void push_local_binding (tree, tree, int);
334extern bool pushdecl_class_level (tree);
335extern tree pushdecl_namespace_level (tree, bool);
336extern bool push_class_level_binding (tree, tree);
337extern tree getdecls (void);
338extern int function_parm_depth (void);
339extern tree cp_namespace_decls (tree);
340extern void set_decl_namespace (tree, tree, bool);
341extern void push_decl_namespace (tree);
342extern void pop_decl_namespace (void);
343extern void do_namespace_alias (tree, tree);
344extern void do_toplevel_using_decl (tree, tree, tree);
345extern void do_local_using_decl (tree, tree, tree);
346extern tree do_class_using_decl (tree, tree);
347extern void do_using_directive (tree);
348extern tree lookup_arg_dependent (tree, tree, vec<tree, va_gc> *);
349extern bool is_associated_namespace (tree, tree);
350extern void parse_using_directive (tree, tree);
351extern tree innermost_non_namespace_value (tree);
352extern cxx_binding *outer_binding (tree, cxx_binding *, bool);
353extern void cp_emit_debug_info_for_using (tree, tree);
354
355/* Set *DECL to the (non-hidden) declaration for ID at global scope,
356   if present and return true; otherwise return false.  */
357
358inline bool
359get_global_value_if_present (tree id, tree *decl)
360{
361  tree global_value = namespace_binding (id, global_namespace);
362  if (global_value)
363    *decl = global_value;
364  return global_value != NULL;
365}
366
367/* True is the binding of IDENTIFIER at global scope names a type.  */
368
369inline bool
370is_typename_at_global_scope (tree id)
371{
372  tree global_value = namespace_binding (id, global_namespace);
373
374  return global_value && TREE_CODE (global_value) == TYPE_DECL;
375}
376
377#endif /* GCC_CP_NAME_LOOKUP_H */
378