1/* Declarations for C++ name lookup routines.
2   Copyright (C) 2003, 2004, 2005  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 2, 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 COPYING.  If not, write to
19the Free Software Foundation, 51 Franklin Street, Fifth Floor,
20Boston, MA 02110-1301, USA.  */
21
22#ifndef GCC_CP_NAME_LOOKUP_H
23#define GCC_CP_NAME_LOOKUP_H
24
25#include "c-common.h"
26
27/* The type of dictionary used to map names to types declared at
28   a given scope.  */
29typedef struct binding_table_s *binding_table;
30typedef struct binding_entry_s *binding_entry;
31
32/* The type of a routine repeatedly called by binding_table_foreach.  */
33typedef void (*bt_foreach_proc) (binding_entry, void *);
34
35struct binding_entry_s GTY(())
36{
37  binding_entry chain;
38  tree name;
39  tree type;
40};
41
42/* These macros indicate the initial chains count for binding_table.  */
43#define SCOPE_DEFAULT_HT_SIZE		(1 << 3)
44#define CLASS_SCOPE_HT_SIZE		(1 << 3)
45#define NAMESPACE_ORDINARY_HT_SIZE	(1 << 5)
46#define NAMESPACE_STD_HT_SIZE		(1 << 8)
47#define GLOBAL_SCOPE_HT_SIZE		(1 << 8)
48
49extern void binding_table_foreach (binding_table, bt_foreach_proc, void *);
50extern binding_entry binding_table_find (binding_table, tree);
51
52/* Datatype that represents binding established by a declaration between
53   a name and a C++ entity.  */
54typedef struct cxx_binding cxx_binding;
55
56/* The datatype used to implement C++ scope.  */
57typedef struct cp_binding_level cxx_scope;
58
59/* Nonzero if this binding is for a local scope, as opposed to a class
60   or namespace scope.  */
61#define LOCAL_BINDING_P(NODE) ((NODE)->is_local)
62
63/* True if NODE->value is from a base class of the class which is
64   currently being defined.  */
65#define INHERITED_VALUE_BINDING_P(NODE) ((NODE)->value_is_inherited)
66
67struct cxx_binding GTY(())
68{
69  /* Link to chain together various bindings for this name.  */
70  cxx_binding *previous;
71  /* The non-type entity this name is bound to.  */
72  tree value;
73  /* The type entity this name is bound to.  */
74  tree type;
75  /* The scope at which this binding was made.  */
76  cxx_scope *scope;
77  unsigned value_is_inherited : 1;
78  unsigned is_local : 1;
79};
80
81/* Datatype used to temporarily save C++ bindings (for implicit
82   instantiations purposes and like).  Implemented in decl.c.  */
83typedef struct cxx_saved_binding GTY(())
84{
85  /* The name of the current binding.  */
86  tree identifier;
87  /* The binding we're saving.  */
88  cxx_binding *binding;
89  tree real_type_value;
90} cxx_saved_binding;
91
92DEF_VEC_O(cxx_saved_binding);
93DEF_VEC_ALLOC_O(cxx_saved_binding,gc);
94
95extern tree identifier_type_value (tree);
96extern void set_identifier_type_value (tree, tree);
97extern void pop_binding (tree, tree);
98extern tree constructor_name (tree);
99extern bool constructor_name_p (tree, tree);
100
101/* The kinds of scopes we recognize.  */
102typedef enum scope_kind {
103  sk_block = 0,      /* An ordinary block scope.  This enumerator must
104			have the value zero because "cp_binding_level"
105			is initialized by using "memset" to set the
106			contents to zero, and the default scope kind
107			is "sk_block".  */
108  sk_cleanup,	     /* A scope for (pseudo-)scope for cleanup.  It is
109			pseudo in that it is transparent to name lookup
110			activities.  */
111  sk_try,	     /* A try-block.  */
112  sk_catch,	     /* A catch-block.  */
113  sk_for,	     /* The scope of the variable declared in a
114			for-init-statement.  */
115  sk_function_parms, /* The scope containing function parameters.  */
116  sk_class,	     /* The scope containing the members of a class.  */
117  sk_namespace,	     /* The scope containing the members of a
118			namespace, including the global scope.  */
119  sk_template_parms, /* A scope for template parameters.  */
120  sk_template_spec,  /* Like sk_template_parms, but for an explicit
121			specialization.  Since, by definition, an
122			explicit specialization is introduced by
123			"template <>", this scope is always empty.  */
124  sk_omp	     /* An OpenMP structured block.  */
125} scope_kind;
126
127/* The scope where the class/struct/union/enum tag applies.  */
128typedef enum tag_scope {
129  ts_current = 0,	/* Current scope only.  This is for the
130			     class-key identifier;
131			   case mentioned in [basic.lookup.elab]/2,
132			   or the class/enum definition
133			     class-key identifier { ... };  */
134  ts_global = 1,	/* All scopes.  This is the 3.4.1
135			   [basic.lookup.unqual] lookup mentioned
136			   in [basic.lookup.elab]/2.  */
137  ts_within_enclosing_non_class = 2	/* Search within enclosing non-class
138					   only, for friend class lookup
139					   according to [namespace.memdef]/3
140					   and [class.friend]/9.  */
141} tag_scope;
142
143typedef struct cp_class_binding GTY(())
144{
145  cxx_binding base;
146  /* The bound name.  */
147  tree identifier;
148} cp_class_binding;
149
150DEF_VEC_O(cp_class_binding);
151DEF_VEC_ALLOC_O(cp_class_binding,gc);
152
153/* For each binding contour we allocate a binding_level structure
154   which records the names defined in that contour.
155   Contours include:
156    0) the global one
157    1) one for each function definition,
158       where internal declarations of the parameters appear.
159    2) one for each compound statement,
160       to record its declarations.
161
162   The current meaning of a name can be found by searching the levels
163   from the current one out to the global one.
164
165   Off to the side, may be the class_binding_level.  This exists only
166   to catch class-local declarations.  It is otherwise nonexistent.
167
168   Also there may be binding levels that catch cleanups that must be
169   run when exceptions occur.  Thus, to see whether a name is bound in
170   the current scope, it is not enough to look in the
171   CURRENT_BINDING_LEVEL.  You should use lookup_name_current_level
172   instead.  */
173
174/* Note that the information in the `names' component of the global contour
175   is duplicated in the IDENTIFIER_GLOBAL_VALUEs of all identifiers.  */
176
177struct cp_binding_level GTY(())
178  {
179    /* A chain of _DECL nodes for all variables, constants, functions,
180       and typedef types.  These are in the reverse of the order
181       supplied.  There may be OVERLOADs on this list, too, but they
182       are wrapped in TREE_LISTs; the TREE_VALUE is the OVERLOAD.  */
183    tree names;
184
185    /* Count of elements in names chain.  */
186    size_t names_size;
187
188    /* A chain of NAMESPACE_DECL nodes.  */
189    tree namespaces;
190
191    /* An array of static functions and variables (for namespaces only) */
192    VEC(tree,gc) *static_decls;
193
194    /* A chain of VTABLE_DECL nodes.  */
195    tree vtables;
196
197    /* A list of USING_DECL nodes.  */
198    tree usings;
199
200    /* A list of used namespaces. PURPOSE is the namespace,
201       VALUE the common ancestor with this binding_level's namespace.  */
202    tree using_directives;
203
204    /* For the binding level corresponding to a class, the entities
205       declared in the class or its base classes.  */
206    VEC(cp_class_binding,gc) *class_shadowed;
207
208    /* Similar to class_shadowed, but for IDENTIFIER_TYPE_VALUE, and
209       is used for all binding levels. The TREE_PURPOSE is the name of
210       the entity, the TREE_TYPE is the associated type.  In addition
211       the TREE_VALUE is the IDENTIFIER_TYPE_VALUE before we entered
212       the class.  */
213    tree type_shadowed;
214
215    /* A TREE_LIST.  Each TREE_VALUE is the LABEL_DECL for a local
216       label in this scope.  The TREE_PURPOSE is the previous value of
217       the IDENTIFIER_LABEL VALUE.  */
218    tree shadowed_labels;
219
220    /* For each level (except not the global one),
221       a chain of BLOCK nodes for all the levels
222       that were entered and exited one level down.  */
223    tree blocks;
224
225    /* The entity (namespace, class, function) the scope of which this
226       binding contour corresponds to.  Otherwise NULL.  */
227    tree this_entity;
228
229    /* The binding level which this one is contained in (inherits from).  */
230    struct cp_binding_level *level_chain;
231
232    /* List of VAR_DECLS saved from a previous for statement.
233       These would be dead in ISO-conforming code, but might
234       be referenced in ARM-era code.  These are stored in a
235       TREE_LIST; the TREE_VALUE is the actual declaration.  */
236    tree dead_vars_from_for;
237
238    /* STATEMENT_LIST for statements in this binding contour.
239       Only used at present for SK_CLEANUP temporary bindings.  */
240    tree statement_list;
241
242    /* Binding depth at which this level began.  */
243    int binding_depth;
244
245    /* The kind of scope that this object represents.  However, a
246       SK_TEMPLATE_SPEC scope is represented with KIND set to
247       SK_TEMPLATE_PARMS and EXPLICIT_SPEC_P set to true.  */
248    ENUM_BITFIELD (scope_kind) kind : 4;
249
250    /* True if this scope is an SK_TEMPLATE_SPEC scope.  This field is
251       only valid if KIND == SK_TEMPLATE_PARMS.  */
252    BOOL_BITFIELD explicit_spec_p : 1;
253
254    /* true means make a BLOCK for this level regardless of all else.  */
255    unsigned keep : 1;
256
257    /* Nonzero if this level can safely have additional
258       cleanup-needing variables added to it.  */
259    unsigned more_cleanups_ok : 1;
260    unsigned have_cleanups : 1;
261
262    /* Nonzero if this level has associated visibility which we should pop
263       when leaving the scope. */
264    unsigned has_visibility : 1;
265
266    /* 23 bits left to fill a 32-bit word.  */
267  };
268
269/* The binding level currently in effect.  */
270
271#define current_binding_level			\
272  (*(cfun && cp_function_chain->bindings	\
273   ? &cp_function_chain->bindings		\
274   : &scope_chain->bindings))
275
276/* The binding level of the current class, if any.  */
277
278#define class_binding_level scope_chain->class_bindings
279
280/* The tree node representing the global scope.  */
281extern GTY(()) tree global_namespace;
282extern GTY(()) tree global_scope_name;
283
284/* Indicates that there is a type value in some namespace, although
285   that is not necessarily in scope at the moment.  */
286
287extern GTY(()) tree global_type_node;
288
289/* True if SCOPE designates the global scope binding contour.  */
290#define global_scope_p(SCOPE) \
291  ((SCOPE) == NAMESPACE_LEVEL (global_namespace))
292
293extern cxx_scope *leave_scope (void);
294extern bool kept_level_p (void);
295extern int global_bindings_p (void);
296extern bool toplevel_bindings_p	(void);
297extern bool namespace_bindings_p (void);
298extern bool template_parm_scope_p (void);
299extern scope_kind innermost_scope_kind (void);
300extern cxx_scope *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 (struct cp_binding_level *);
312
313extern void push_namespace (tree);
314extern void push_namespace_with_attribs (tree, tree);
315extern void pop_namespace (void);
316extern void push_nested_namespace (tree);
317extern void pop_nested_namespace (tree);
318extern void pushlevel_class (void);
319extern void poplevel_class (void);
320extern tree pushdecl_with_scope (tree, cxx_scope *, 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_function_nonclass (tree, tree, bool);
331extern void push_local_binding (tree, tree, int);
332extern bool pushdecl_class_level (tree);
333extern tree pushdecl_namespace_level (tree, bool);
334extern bool push_class_level_binding (tree, tree);
335extern tree getdecls (void);
336extern tree cp_namespace_decls (tree);
337extern void set_decl_namespace (tree, tree, bool);
338extern void push_decl_namespace (tree);
339extern void pop_decl_namespace (void);
340extern void do_namespace_alias (tree, tree);
341extern void do_toplevel_using_decl (tree, tree, tree);
342extern void do_local_using_decl (tree, tree, tree);
343extern tree do_class_using_decl (tree, tree);
344extern void do_using_directive (tree);
345extern tree lookup_arg_dependent (tree, tree, tree);
346extern bool is_associated_namespace (tree, tree);
347extern void parse_using_directive (tree, tree);
348extern tree innermost_non_namespace_value (tree);
349extern cxx_binding *outer_binding (tree, cxx_binding *, bool);
350extern void cp_emit_debug_info_for_using (tree, tree);
351
352/* Set *DECL to the (non-hidden) declaration for ID at global scope,
353   if present and return true; otherwise return false.  */
354
355static inline bool
356get_global_value_if_present (tree id, tree *decl)
357{
358  tree global_value = namespace_binding (id, global_namespace);
359  if (global_value)
360    *decl = global_value;
361  return global_value != NULL;
362}
363
364/* True is the binding of IDENTIFIER at global scope names a type.  */
365
366static inline bool
367is_typename_at_global_scope (tree id)
368{
369  tree global_value = namespace_binding (id, global_namespace);
370
371  return global_value && TREE_CODE (global_value) == TYPE_DECL;
372}
373
374#endif /* GCC_CP_NAME_LOOKUP_H */
375