name-lookup.h revision 1.6 
1/* Declarations for C++ name lookup routines.
2   Copyright (C) 2003-2016 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.  */
80struct 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};
87
88
89extern tree identifier_type_value (tree);
90extern void set_identifier_type_value (tree, tree);
91extern void push_binding (tree, tree, cp_binding_level*);
92extern void pop_binding (tree, tree);
93extern void pop_bindings_and_leave_scope (void);
94extern tree constructor_name (tree);
95extern bool constructor_name_p (tree, tree);
96
97/* The kinds of scopes we recognize.  */
98enum scope_kind {
99  sk_block = 0,      /* An ordinary block scope.  This enumerator must
100			have the value zero because "cp_binding_level"
101			is initialized by using "memset" to set the
102			contents to zero, and the default scope kind
103			is "sk_block".  */
104  sk_cleanup,	     /* A scope for (pseudo-)scope for cleanup.  It is
105			pseudo in that it is transparent to name lookup
106			activities.  */
107  sk_try,	     /* A try-block.  */
108  sk_catch,	     /* A catch-block.  */
109  sk_for,	     /* The scope of the variable declared in a
110			for-init-statement.  */
111  sk_cond,	     /* The scope of the variable declared in the condition
112			of an if or switch statement.  */
113  sk_function_parms, /* The scope containing function parameters.  */
114  sk_class,	     /* The scope containing the members of a class.  */
115  sk_scoped_enum,    /* The scope containing the enumertors of a C++0x
116                        scoped enumeration.  */
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_transaction,    /* A synchronized or atomic statement.  */
125  sk_omp	     /* An OpenMP structured block.  */
126};
127
128/* The scope where the class/struct/union/enum tag applies.  */
129enum tag_scope {
130  ts_current = 0,	/* Current scope only.  This is for the
131			     class-key identifier;
132			   case mentioned in [basic.lookup.elab]/2,
133			   or the class/enum definition
134			     class-key identifier { ... };  */
135  ts_global = 1,	/* All scopes.  This is the 3.4.1
136			   [basic.lookup.unqual] lookup mentioned
137			   in [basic.lookup.elab]/2.  */
138  ts_within_enclosing_non_class = 2,	/* Search within enclosing non-class
139					   only, for friend class lookup
140					   according to [namespace.memdef]/3
141					   and [class.friend]/9.  */
142  ts_lambda = 3			/* Declaring a lambda closure.  */
143};
144
145struct GTY(()) cp_class_binding {
146  cxx_binding *base;
147  /* The bound name.  */
148  tree identifier;
149};
150
151
152struct GTY(()) cp_label_binding {
153  /* The bound LABEL_DECL.  */
154  tree label;
155  /* The previous IDENTIFIER_LABEL_VALUE.  */
156  tree prev_value;
157};
158
159
160/* For each binding contour we allocate a binding_level structure
161   which records the names defined in that contour.
162   Contours include:
163    0) the global one
164    1) one for each function definition,
165       where internal declarations of the parameters appear.
166    2) one for each compound statement,
167       to record its declarations.
168
169   The current meaning of a name can be found by searching the levels
170   from the current one out to the global one.
171
172   Off to the side, may be the class_binding_level.  This exists only
173   to catch class-local declarations.  It is otherwise nonexistent.
174
175   Also there may be binding levels that catch cleanups that must be
176   run when exceptions occur.  Thus, to see whether a name is bound in
177   the current scope, it is not enough to look in the
178   CURRENT_BINDING_LEVEL.  You should use lookup_name_current_level
179   instead.  */
180
181/* Note that the information in the `names' component of the global contour
182   is duplicated in the IDENTIFIER_GLOBAL_VALUEs of all identifiers.  */
183
184struct GTY(()) cp_binding_level {
185  /* A chain of _DECL nodes for all variables, constants, functions,
186      and typedef types.  These are in the reverse of the order
187      supplied.  There may be OVERLOADs on this list, too, but they
188      are wrapped in TREE_LISTs; the TREE_VALUE is the OVERLOAD.  */
189  tree names;
190
191  /* A chain of NAMESPACE_DECL nodes.  */
192  tree namespaces;
193
194  /* An array of static functions and variables (for namespaces only) */
195  vec<tree, va_gc> *static_decls;
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, va_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  /* Similar to class_shadowed, but for IDENTIFIER_LABEL_VALUE, and
216      used for all binding levels.  */
217  vec<cp_label_binding, va_gc> *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  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.  */
234  vec<tree, va_gc> *dead_vars_from_for;
235
236  /* STATEMENT_LIST for statements in this binding contour.
237      Only used at present for SK_CLEANUP temporary bindings.  */
238  tree statement_list;
239
240  /* Binding depth at which this level began.  */
241  int binding_depth;
242
243  /* The kind of scope that this object represents.  However, a
244      SK_TEMPLATE_SPEC scope is represented with KIND set to
245      SK_TEMPLATE_PARMS and EXPLICIT_SPEC_P set to true.  */
246  ENUM_BITFIELD (scope_kind) kind : 4;
247
248  /* True if this scope is an SK_TEMPLATE_SPEC scope.  This field is
249      only valid if KIND == SK_TEMPLATE_PARMS.  */
250  BOOL_BITFIELD explicit_spec_p : 1;
251
252  /* true means make a BLOCK for this level regardless of all else.  */
253  unsigned keep : 1;
254
255  /* Nonzero if this level can safely have additional
256      cleanup-needing variables added to it.  */
257  unsigned more_cleanups_ok : 1;
258  unsigned have_cleanups : 1;
259
260  /* Transient state set if this scope is of sk_class kind
261     and is in the process of defining 'this_entity'.  Reset
262     on leaving the class definition to allow for the scope
263     to be subsequently re-used as a non-defining scope for
264     'this_entity'.  */
265  unsigned defining_class_p : 1;
266
267  /* 23 bits left to fill a 32-bit word.  */
268};
269
270/* The binding level currently in effect.  */
271
272#define current_binding_level			\
273  (*(cfun && cp_function_chain && cp_function_chain->bindings \
274   ? &cp_function_chain->bindings		\
275   : &scope_chain->bindings))
276
277/* The binding level of the current class, if any.  */
278
279#define class_binding_level scope_chain->class_bindings
280
281/* The tree node representing the global scope.  */
282extern GTY(()) tree global_namespace;
283extern GTY(()) tree global_scope_name;
284
285/* Indicates that there is a type value in some namespace, although
286   that is not necessarily in scope at the moment.  */
287
288extern GTY(()) tree global_type_node;
289
290/* True if SCOPE designates the global scope binding contour.  */
291#define global_scope_p(SCOPE) \
292  ((SCOPE) == NAMESPACE_LEVEL (global_namespace))
293
294extern cp_binding_level *leave_scope (void);
295extern bool kept_level_p (void);
296extern bool global_bindings_p (void);
297extern bool toplevel_bindings_p	(void);
298extern bool namespace_bindings_p (void);
299extern bool local_bindings_p (void);
300extern bool template_parm_scope_p (void);
301extern scope_kind innermost_scope_kind (void);
302extern cp_binding_level *begin_scope (scope_kind, tree);
303extern void print_binding_stack	(void);
304extern void push_to_top_level (void);
305extern void pop_from_top_level (void);
306extern void pop_everything (void);
307extern void keep_next_level (bool);
308extern bool is_ancestor (tree, tree);
309extern tree push_scope (tree);
310extern void pop_scope (tree);
311extern tree push_inner_scope (tree);
312extern void pop_inner_scope (tree, tree);
313extern void push_binding_level (cp_binding_level *);
314
315extern void push_namespace (tree);
316extern void pop_namespace (void);
317extern void push_nested_namespace (tree);
318extern void pop_nested_namespace (tree);
319extern bool handle_namespace_attrs (tree, tree);
320extern void pushlevel_class (void);
321extern void poplevel_class (void);
322extern tree pushdecl_with_scope (tree, cp_binding_level *, bool);
323extern tree lookup_name_prefer_type (tree, int);
324extern tree lookup_name_real (tree, int, int, bool, int, int);
325extern tree lookup_type_scope (tree, tag_scope);
326extern tree namespace_binding (tree, tree);
327extern void set_namespace_binding (tree, tree, tree);
328extern bool hidden_name_p (tree);
329extern tree remove_hidden_names (tree);
330extern tree lookup_qualified_name (tree, tree, int, bool, /*hidden*/bool = false);
331extern tree lookup_name_nonclass (tree);
332extern tree lookup_name_innermost_nonclass_level (tree);
333extern bool is_local_extern (tree);
334extern tree lookup_function_nonclass (tree, vec<tree, va_gc> *, bool);
335extern void push_local_binding (tree, tree, int);
336extern bool pushdecl_class_level (tree);
337extern tree pushdecl_namespace_level (tree, bool);
338extern bool push_class_level_binding (tree, tree);
339extern tree getdecls (void);
340extern int function_parm_depth (void);
341extern tree cp_namespace_decls (tree);
342extern void set_decl_namespace (tree, tree, bool);
343extern void push_decl_namespace (tree);
344extern void pop_decl_namespace (void);
345extern void do_namespace_alias (tree, tree);
346extern void do_toplevel_using_decl (tree, tree, tree);
347extern void do_local_using_decl (tree, tree, tree);
348extern tree do_class_using_decl (tree, tree);
349extern void do_using_directive (tree);
350extern cp_expr lookup_arg_dependent (tree, tree, vec<tree, va_gc> *);
351extern bool is_associated_namespace (tree, tree);
352extern void parse_using_directive (tree, tree);
353extern tree innermost_non_namespace_value (tree);
354extern cxx_binding *outer_binding (tree, cxx_binding *, bool);
355extern void cp_emit_debug_info_for_using (tree, tree);
356
357/* Set *DECL to the (non-hidden) declaration for ID at global scope,
358   if present and return true; otherwise return false.  */
359
360inline bool
361get_global_value_if_present (tree id, tree *decl)
362{
363  tree global_value = namespace_binding (id, global_namespace);
364  if (global_value)
365    *decl = global_value;
366  return global_value != NULL;
367}
368
369/* True is the binding of IDENTIFIER at global scope names a type.  */
370
371inline bool
372is_typename_at_global_scope (tree id)
373{
374  tree global_value = namespace_binding (id, global_namespace);
375
376  return global_value && TREE_CODE (global_value) == TYPE_DECL;
377}
378
379#endif /* GCC_CP_NAME_LOOKUP_H */
380