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			peusdo 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} 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} tag_scope;
141
142typedef struct cp_class_binding GTY(())
143{
144  cxx_binding base;
145  /* The bound name.  */
146  tree identifier;
147} cp_class_binding;
148
149DEF_VEC_O(cp_class_binding);
150DEF_VEC_ALLOC_O(cp_class_binding,gc);
151
152/* For each binding contour we allocate a binding_level structure
153   which records the names defined in that contour.
154   Contours include:
155    0) the global one
156    1) one for each function definition,
157       where internal declarations of the parameters appear.
158    2) one for each compound statement,
159       to record its declarations.
160
161   The current meaning of a name can be found by searching the levels
162   from the current one out to the global one.
163
164   Off to the side, may be the class_binding_level.  This exists only
165   to catch class-local declarations.  It is otherwise nonexistent.
166
167   Also there may be binding levels that catch cleanups that must be
168   run when exceptions occur.  Thus, to see whether a name is bound in
169   the current scope, it is not enough to look in the
170   CURRENT_BINDING_LEVEL.  You should use lookup_name_current_level
171   instead.  */
172
173/* Note that the information in the `names' component of the global contour
174   is duplicated in the IDENTIFIER_GLOBAL_VALUEs of all identifiers.  */
175
176struct cp_binding_level GTY(())
177  {
178    /* A chain of _DECL nodes for all variables, constants, functions,
179       and typedef types.  These are in the reverse of the order
180       supplied.  There may be OVERLOADs on this list, too, but they
181       are wrapped in TREE_LISTs; the TREE_VALUE is the OVERLOAD.  */
182    tree names;
183
184    /* Count of elements in names chain.  */
185    size_t names_size;
186
187    /* A chain of NAMESPACE_DECL nodes.  */
188    tree namespaces;
189
190    /* An array of static functions and variables (for namespaces only) */
191    VEC(tree,gc) *static_decls;
192
193    /* A chain of VTABLE_DECL nodes.  */
194    tree vtables;
195
196    /* A list of USING_DECL nodes.  */
197    tree usings;
198
199    /* A list of used namespaces. PURPOSE is the namespace,
200       VALUE the common ancestor with this binding_level's namespace.  */
201    tree using_directives;
202
203    /* For the binding level corresponding to a class, the entities
204       declared in the class or its base classes.  */
205    VEC(cp_class_binding,gc) *class_shadowed;
206
207    /* Similar to class_shadowed, but for IDENTIFIER_TYPE_VALUE, and
208       is used for all binding levels. The TREE_PURPOSE is the name of
209       the entity, the TREE_TYPE is the associated type.  In addition
210       the TREE_VALUE is the IDENTIFIER_TYPE_VALUE before we entered
211       the class.  */
212    tree type_shadowed;
213
214    /* A TREE_LIST.  Each TREE_VALUE is the LABEL_DECL for a local
215       label in this scope.  The TREE_PURPOSE is the previous value of
216       the IDENTIFIER_LABEL VALUE.  */
217    tree shadowed_labels;
218
219    /* For each level (except not the global one),
220       a chain of BLOCK nodes for all the levels
221       that were entered and exited one level down.  */
222    tree blocks;
223
224    /* The entity (namespace, class, function) the scope of which this
225       binding contour corresponds to.  Otherwise NULL.  */
226    tree this_entity;
227
228    /* The binding level which this one is contained in (inherits from).  */
229    struct cp_binding_level *level_chain;
230
231    /* List of VAR_DECLS saved from a previous for statement.
232       These would be dead in ISO-conforming code, but might
233       be referenced in ARM-era code.  These are stored in a
234       TREE_LIST; the TREE_VALUE is the actual declaration.  */
235    tree dead_vars_from_for;
236
237    /* STATEMENT_LIST for statements in this binding contour.
238       Only used at present for SK_CLEANUP temporary bindings.  */
239    tree statement_list;
240
241    /* Binding depth at which this level began.  */
242    int binding_depth;
243
244    /* The kind of scope that this object represents.  However, a
245       SK_TEMPLATE_SPEC scope is represented with KIND set to
246       SK_TEMPLATE_PARMS and EXPLICIT_SPEC_P set to true.  */
247    ENUM_BITFIELD (scope_kind) kind : 4;
248
249    /* True if this scope is an SK_TEMPLATE_SPEC scope.  This field is
250       only valid if KIND == SK_TEMPLATE_PARMS.  */
251    BOOL_BITFIELD explicit_spec_p : 1;
252
253    /* true means make a BLOCK for this level regardless of all else.  */
254    unsigned keep : 1;
255
256    /* Nonzero if this level can safely have additional
257       cleanup-needing variables added to it.  */
258    unsigned more_cleanups_ok : 1;
259    unsigned have_cleanups : 1;
260
261    /* 22 bits left to fill a 32-bit word.  */
262  };
263
264/* The binding level currently in effect.  */
265
266#define current_binding_level			\
267  (*(cfun && cp_function_chain->bindings	\
268   ? &cp_function_chain->bindings		\
269   : &scope_chain->bindings))
270
271/* The binding level of the current class, if any.  */
272
273#define class_binding_level scope_chain->class_bindings
274
275/* The tree node representing the global scope.  */
276extern GTY(()) tree global_namespace;
277extern GTY(()) tree global_scope_name;
278
279/* Indicates that there is a type value in some namespace, although
280   that is not necessarily in scope at the moment.  */
281
282extern GTY(()) tree global_type_node;
283
284/* True if SCOPE designates the global scope binding contour.  */
285#define global_scope_p(SCOPE) \
286  ((SCOPE) == NAMESPACE_LEVEL (global_namespace))
287
288extern cxx_scope *leave_scope (void);
289extern bool kept_level_p (void);
290extern int global_bindings_p (void);
291extern bool toplevel_bindings_p	(void);
292extern bool namespace_bindings_p (void);
293extern bool template_parm_scope_p (void);
294extern scope_kind innermost_scope_kind (void);
295extern cxx_scope *begin_scope (scope_kind, tree);
296extern void print_binding_stack	(void);
297extern void push_to_top_level (void);
298extern void pop_from_top_level (void);
299extern void pop_everything (void);
300extern void keep_next_level (bool);
301extern bool is_ancestor (tree, tree);
302extern tree push_scope (tree);
303extern void pop_scope (tree);
304extern tree push_inner_scope (tree);
305extern void pop_inner_scope (tree, tree);
306extern void push_binding_level (struct cp_binding_level *);
307
308extern void push_namespace (tree);
309extern void pop_namespace (void);
310extern void push_nested_namespace (tree);
311extern void pop_nested_namespace (tree);
312extern void pushlevel_class (void);
313extern void poplevel_class (void);
314extern tree pushdecl_with_scope (tree, cxx_scope *, bool);
315extern tree lookup_name	(tree, int);
316extern tree lookup_name_one (tree);
317extern tree lookup_name_real (tree, int, int, bool, int, int);
318extern tree lookup_type_scope (tree, tag_scope);
319extern tree namespace_binding (tree, tree);
320extern void set_namespace_binding (tree, tree, tree);
321extern bool hidden_name_p (tree);
322extern tree remove_hidden_names (tree);
323extern tree lookup_namespace_name (tree, tree);
324extern tree lookup_qualified_name (tree, tree, bool, bool);
325extern tree lookup_name_nonclass (tree);
326extern tree lookup_function_nonclass (tree, tree, bool);
327extern void push_local_binding (tree, tree, int);
328extern bool pushdecl_class_level (tree);
329extern tree pushdecl_namespace_level (tree, bool);
330extern bool push_class_level_binding (tree, tree);
331extern tree getdecls (void);
332extern tree cp_namespace_decls (tree);
333extern void set_decl_namespace (tree, tree, bool);
334extern void push_decl_namespace (tree);
335extern void pop_decl_namespace (void);
336extern void do_namespace_alias (tree, tree);
337extern void do_toplevel_using_decl (tree, tree, tree);
338extern void do_local_using_decl (tree, tree, tree);
339extern tree do_class_using_decl (tree, tree);
340extern void do_using_directive (tree);
341extern tree lookup_arg_dependent (tree, tree, tree);
342extern bool is_associated_namespace (tree, tree);
343extern void parse_using_directive (tree, tree);
344extern tree innermost_non_namespace_value (tree);
345extern cxx_binding *outer_binding (tree, cxx_binding *, bool);
346extern void cp_emit_debug_info_for_using (tree, tree);
347
348/* Set *DECL to the (non-hidden) declaration for ID at global scope,
349   if present and return true; otherwise return false.  */
350
351static inline bool
352get_global_value_if_present (tree id, tree *decl)
353{
354  tree global_value = namespace_binding (id, global_namespace);
355  if (global_value)
356    *decl = global_value;
357  return global_value != NULL;
358}
359
360/* True is the binding of IDENTIFIER at global scope names a type.  */
361
362static inline bool
363is_typename_at_global_scope (tree id)
364{
365  tree global_value = namespace_binding (id, global_namespace);
366
367  return global_value && TREE_CODE (global_value) == TYPE_DECL;
368}
369
370#endif /* GCC_CP_NAME_LOOKUP_H */
371