gcc/cp/name-lookup.h

   1 /* Declarations for -*- C++ -*- name lookup routines.
   2    Copyright (C) 2003-2023 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 \f
  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.cc.  */
  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   }
  92   bool is_lazy () const
  93   {
  94     return bool (uintptr_t (u.binding) & 1);
  95   }
  96   void set_lazy (unsigned snum)
  97   {
  98     gcc_checking_assert (!u.binding);
  99     u.binding = tree (uintptr_t ((snum << 1) | 1));
 100   }
 101   void or_lazy (unsigned snum)
 102   {
 103     gcc_checking_assert (is_lazy ());
 104     u.binding = tree (uintptr_t (u.binding) | (snum << 1));
 105   }
 106   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 \f
 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_stmt_expr,      /* GNU statement expression block.  */
 204   sk_function_parms, /* The scope containing function parameters.  */
 205   sk_class,          /* The scope containing the members of a class.  */
 206   sk_scoped_enum,    /* The scope containing the enumerators of a C++11
 207                         scoped enumeration.  */
 208   sk_namespace,      /* The scope containing the members of a
 209                         namespace, including the global scope.  */
 210   sk_template_parms, /* A scope for template parameters.  */
 211   sk_template_spec,  /* Like sk_template_parms, but for an explicit
 212                         specialization.  Since, by definition, an
 213                         explicit specialization is introduced by
 214                         "template <>", this scope is always empty.  */
 215   sk_transaction,    /* A synchronized or atomic statement.  */
 216   sk_omp             /* An OpenMP structured block.  */
 217 };
 218
 219 struct GTY(()) cp_class_binding {
 220   cxx_binding *base;
 221   /* The bound name.  */
 222   tree identifier;
 223 };
 224
 225 /* For each binding contour we allocate a binding_level structure
 226    which records the names defined in that contour.
 227    Contours include:
 228     0) the global one
 229     1) one for each function definition,
 230        where internal declarations of the parameters appear.
 231     2) one for each compound statement,
 232        to record its declarations.
 233
 234    The current meaning of a name can be found by searching the levels
 235    from the current one out to the global one.
 236
 237    Off to the side, may be the class_binding_level.  This exists only
 238    to catch class-local declarations.  It is otherwise nonexistent.
 239
 240    Also there may be binding levels that catch cleanups that must be
 241    run when exceptions occur.  Thus, to see whether a name is bound in
 242    the current scope, it is not enough to look in the
 243    CURRENT_BINDING_LEVEL.  You should use lookup_name_current_level
 244    instead.  */
 245
 246 struct GTY(()) cp_binding_level {
 247   /* A chain of _DECL nodes for all variables, constants, functions,
 248       and typedef types.  These are in the reverse of the order
 249       supplied.  There may be OVERLOADs on this list, too, but they
 250       are wrapped in TREE_LISTs; the TREE_VALUE is the OVERLOAD.  */
 251   tree names;
 252
 253   /* Using directives.  */
 254   vec<tree, va_gc> *using_directives;
 255
 256   /* For the binding level corresponding to a class, the entities
 257       declared in the class or its base classes.  */
 258   vec<cp_class_binding, va_gc> *class_shadowed;
 259
 260   /* Similar to class_shadowed, but for IDENTIFIER_TYPE_VALUE, and
 261       is used for all binding levels. The TREE_PURPOSE is the name of
 262       the entity, the TREE_TYPE is the associated type.  In addition
 263       the TREE_VALUE is the IDENTIFIER_TYPE_VALUE before we entered
 264       the class.  */
 265   tree type_shadowed;
 266
 267   /* For each level (except not the global one),
 268       a chain of BLOCK nodes for all the levels
 269       that were entered and exited one level down.  */
 270   tree blocks;
 271
 272   /* The entity (namespace, class, function) the scope of which this
 273       binding contour corresponds to.  Otherwise NULL.  */
 274   tree this_entity;
 275
 276   /* The binding level which this one is contained in (inherits from).  */
 277   cp_binding_level *level_chain;
 278
 279   /* STATEMENT_LIST for statements in this binding contour.
 280       Only used at present for SK_CLEANUP temporary bindings.  */
 281   tree statement_list;
 282
 283   /* Binding depth at which this level began.  */
 284   int binding_depth;
 285
 286   /* The kind of scope that this object represents.  However, a
 287       SK_TEMPLATE_SPEC scope is represented with KIND set to
 288       SK_TEMPLATE_PARMS and EXPLICIT_SPEC_P set to true.  */
 289   ENUM_BITFIELD (scope_kind) kind : 4;
 290
 291   /* True if this scope is an SK_TEMPLATE_SPEC scope.  This field is
 292       only valid if KIND == SK_TEMPLATE_PARMS.  */
 293   BOOL_BITFIELD explicit_spec_p : 1;
 294
 295   /* true means make a BLOCK for this level regardless of all else.  */
 296   unsigned keep : 1;
 297
 298   /* Nonzero if this level can safely have additional
 299       cleanup-needing variables added to it.  */
 300   unsigned more_cleanups_ok : 1;
 301   unsigned have_cleanups : 1;
 302
 303   /* Transient state set if this scope is of sk_class kind
 304      and is in the process of defining 'this_entity'.  Reset
 305      on leaving the class definition to allow for the scope
 306      to be subsequently re-used as a non-defining scope for
 307      'this_entity'.  */
 308   unsigned defining_class_p : 1;
 309
 310   /* True for SK_FUNCTION_PARMS of a requires-expression.  */
 311   unsigned requires_expression: 1;
 312
 313   /* 22 bits left to fill a 32-bit word.  */
 314 };
 315
 316 /* The binding level currently in effect.  */
 317
 318 #define current_binding_level                   \
 319   (*(cfun && cp_function_chain && cp_function_chain->bindings \
 320    ? &cp_function_chain->bindings               \
 321    : &scope_chain->bindings))
 322
 323 /* The binding level of the current class, if any.  */
 324
 325 #define class_binding_level scope_chain->class_bindings
 326
 327 /* True if SCOPE designates the global scope binding contour.  */
 328 #define global_scope_p(SCOPE) \
 329   ((SCOPE) == NAMESPACE_LEVEL (global_namespace))
 330
 331 extern cp_binding_level *leave_scope (void);
 332 extern bool kept_level_p (void);
 333 extern bool global_bindings_p (void);
 334 extern bool toplevel_bindings_p (void);
 335 extern bool namespace_bindings_p (void);
 336 extern bool local_bindings_p (void);
 337 extern bool template_parm_scope_p (void);
 338 extern scope_kind innermost_scope_kind (void);
 339 extern cp_binding_level *begin_scope (scope_kind, tree);
 340 extern void print_binding_stack (void);
 341 extern void pop_everything (void);
 342 extern void keep_next_level (bool);
 343 extern bool is_ancestor (tree ancestor, tree descendant);
 344 extern bool is_nested_namespace (tree parent, tree descendant,
 345                                  bool inline_only = false);
 346 extern tree push_scope (tree);
 347 extern void pop_scope (tree);
 348 extern tree push_inner_scope (tree);
 349 extern void pop_inner_scope (tree, tree);
 350 extern void push_binding_level (cp_binding_level *);
 351 \f
 352 extern bool handle_namespace_attrs (tree, tree);
 353 extern void pushlevel_class (void);
 354 extern void poplevel_class (void);
 355
 356 /* What kind of scopes name lookup looks in.  An enum class so we
 357    don't accidentally mix integers.  */
 358 enum class LOOK_where
 359 {
 360   BLOCK = 1 << 0,  /* Consider block scopes.  */
 361   CLASS = 1 << 1,  /* Consider class scopes.  */
 362   NAMESPACE = 1 << 2,  /* Consider namespace scopes.  */
 363
 364   ALL = BLOCK | CLASS | NAMESPACE,
 365   BLOCK_NAMESPACE = BLOCK | NAMESPACE,
 366   CLASS_NAMESPACE = CLASS | NAMESPACE,
 367 };
 368 constexpr LOOK_where operator| (LOOK_where a, LOOK_where b)
 369 {
 370   return LOOK_where (unsigned (a) | unsigned (b));
 371 }
 372 constexpr LOOK_where operator& (LOOK_where a, LOOK_where b)
 373 {
 374   return LOOK_where (unsigned (a) & unsigned (b));
 375 }
 376
 377 enum class LOOK_want
 378 {
 379   NORMAL = 0,  /* Normal lookup -- non-types can hide implicit types.  */
 380   TYPE = 1 << 1,  /* We only want TYPE_DECLS.  */
 381   NAMESPACE = 1 << 2,  /* We only want NAMESPACE_DECLS.  */
 382
 383   HIDDEN_FRIEND = 1 << 3, /* See hidden friends.  */
 384   HIDDEN_LAMBDA = 1 << 4,  /* See lambda-ignored entities.  */
 385
 386   TYPE_NAMESPACE = TYPE | NAMESPACE,  /* Either NAMESPACE or TYPE.  */
 387 };
 388 constexpr LOOK_want operator| (LOOK_want a, LOOK_want b)
 389 {
 390   return LOOK_want (unsigned (a) | unsigned (b));
 391 }
 392 constexpr LOOK_want operator& (LOOK_want a, LOOK_want b)
 393 {
 394   return LOOK_want (unsigned (a) & unsigned (b));
 395 }
 396
 397 extern tree lookup_name (tree, LOOK_where, LOOK_want = LOOK_want::NORMAL);
 398 /* Also declared in c-family/c-common.h.  */
 399 extern tree lookup_name (tree name);
 400 inline tree lookup_name (tree name, LOOK_want want)
 401 {
 402   return lookup_name (name, LOOK_where::ALL, want);
 403 }
 404
 405 enum class TAG_how
 406 {
 407   CURRENT_ONLY = 0, // Look and insert only in current scope
 408
 409   GLOBAL = 1, // Unqualified lookup, innermost-non-class insertion
 410
 411   INNERMOST_NON_CLASS = 2, // Look and insert only into
 412                            // innermost-non-class
 413
 414   HIDDEN_FRIEND = 3, // As INNERMOST_NON_CLASS, but hide it
 415 };
 416
 417 extern tree lookup_elaborated_type (tree, TAG_how);
 418 extern tree get_namespace_binding (tree ns, tree id);
 419 extern void set_global_binding (tree decl);
 420 inline tree get_global_binding (tree id)
 421 {
 422   return get_namespace_binding (NULL_TREE, id);
 423 }
 424 extern tree lookup_qualified_name (tree scope, tree name,
 425                                    LOOK_want = LOOK_want::NORMAL,
 426                                    bool = true);
 427 extern tree lookup_qualified_name (tree scope, const char *name,
 428                                    LOOK_want = LOOK_want::NORMAL,
 429                                    bool = true);
 430 extern bool pushdecl_class_level (tree);
 431 extern tree pushdecl_namespace_level (tree, bool hiding = false);
 432 extern bool push_class_level_binding (tree, tree);
 433 extern tree get_local_decls ();
 434 extern int function_parm_depth (void);
 435 extern tree cp_namespace_decls (tree);
 436 extern void set_decl_namespace (tree, tree, bool);
 437 extern void push_decl_namespace (tree);
 438 extern void pop_decl_namespace (void);
 439 extern void do_namespace_alias (tree, tree);
 440 extern tree do_class_using_decl (tree, tree);
 441 extern tree lookup_arg_dependent (tree, tree, vec<tree, va_gc> *);
 442 extern tree search_anon_aggr (tree, tree, bool = false);
 443 extern tree get_class_binding_direct (tree, tree, bool want_type = false);
 444 extern tree get_class_binding (tree, tree, bool want_type = false);
 445 extern tree *find_member_slot (tree klass, tree name);
 446 extern tree *add_member_slot (tree klass, tree name);
 447 extern void resort_type_member_vec (void *, void *,
 448                                     gt_pointer_operator, void *);
 449 extern vec<tree, va_gc> *set_class_bindings (tree, int extra = 0);
 450 extern void insert_late_enum_def_bindings (tree, tree);
 451 extern tree innermost_non_namespace_value (tree);
 452 extern bool decl_in_scope_p (tree);
 453 extern cxx_binding *outer_binding (tree, cxx_binding *, bool);
 454 extern void cp_emit_debug_info_for_using (tree, tree);
 455
 456 extern void finish_nonmember_using_decl (tree scope, tree name);
 457 extern void finish_using_directive (tree target, tree attribs);
 458 void push_local_extern_decl_alias (tree decl);
 459 extern tree pushdecl (tree, bool hiding = false);
 460 extern tree pushdecl_outermost_localscope (tree);
 461 extern tree pushdecl_top_level (tree);
 462 extern tree pushdecl_top_level_and_finish (tree, tree);
 463 extern tree pushtag (tree, tree, TAG_how = TAG_how::CURRENT_ONLY);
 464 extern int push_namespace (tree, bool make_inline = false);
 465 extern void pop_namespace (void);
 466 extern void push_nested_namespace (tree);
 467 extern void pop_nested_namespace (tree);
 468 extern void push_to_top_level (void);
 469 extern void pop_from_top_level (void);
 470 extern bool maybe_push_to_top_level (tree);
 471 extern void maybe_pop_from_top_level (bool);
 472 extern void push_using_decl_bindings (tree, tree);
 473
 474 /* Lower level interface for modules. */
 475 extern tree *mergeable_namespace_slots (tree ns, tree name, bool is_attached,
 476                                         tree *mvec);
 477 extern void add_mergeable_namespace_entity (tree *slot, tree decl);
 478 extern tree lookup_class_binding (tree ctx, tree name);
 479 extern bool import_module_binding (tree ctx, tree name, unsigned mod,
 480                                    unsigned snum);
 481 extern bool set_module_binding (tree ctx, tree name, unsigned mod,
 482                                 int mod_glob_flag,
 483                                 tree value, tree type, tree visible);
 484 extern void add_module_namespace_decl (tree ns, tree decl);
 485
 486 enum WMB_Flags
 487 {
 488   WMB_None = 0,
 489   WMB_Dups = 1 << 0,
 490   WMB_Export = 1 << 1,
 491   WMB_Using = 1 << 2,
 492   WMB_Hidden = 1 << 3,
 493 };
 494
 495 extern unsigned walk_module_binding (tree binding, bitmap partitions,
 496                                      bool (*)(tree decl, WMB_Flags, void *data),
 497                                      void *data);
 498 extern tree add_imported_namespace (tree ctx, tree name, location_t,
 499                                     unsigned module,
 500                                     bool inline_p, bool visible_p);
 501 extern const char *get_cxx_dialect_name (enum cxx_dialect dialect);
 502
 503 #endif /* GCC_CP_NAME_LOOKUP_H */