gcc/cp/name-lookup.h

   1 /* Declarations for -*- C++ -*- name lookup routines.
   2    Copyright (C) 2003-2021 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.c.  */
  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_function_parms, /* The scope containing function parameters.  */
 204   sk_class,          /* The scope containing the members of a class.  */
 205   sk_scoped_enum,    /* The scope containing the enumerators of a C++11
 206                         scoped enumeration.  */
 207   sk_namespace,      /* The scope containing the members of a
 208                         namespace, including the global scope.  */
 209   sk_template_parms, /* A scope for template parameters.  */
 210   sk_template_spec,  /* Like sk_template_parms, but for an explicit
 211                         specialization.  Since, by definition, an
 212                         explicit specialization is introduced by
 213                         "template <>", this scope is always empty.  */
 214   sk_transaction,    /* A synchronized or atomic statement.  */
 215   sk_omp             /* An OpenMP structured block.  */
 216 };
 217
 218 struct GTY(()) cp_class_binding {
 219   cxx_binding *base;
 220   /* The bound name.  */
 221   tree identifier;
 222 };
 223
 224 /* For each binding contour we allocate a binding_level structure
 225    which records the names defined in that contour.
 226    Contours include:
 227     0) the global one
 228     1) one for each function definition,
 229        where internal declarations of the parameters appear.
 230     2) one for each compound statement,
 231        to record its declarations.
 232
 233    The current meaning of a name can be found by searching the levels
 234    from the current one out to the global one.
 235
 236    Off to the side, may be the class_binding_level.  This exists only
 237    to catch class-local declarations.  It is otherwise nonexistent.
 238
 239    Also there may be binding levels that catch cleanups that must be
 240    run when exceptions occur.  Thus, to see whether a name is bound in
 241    the current scope, it is not enough to look in the
 242    CURRENT_BINDING_LEVEL.  You should use lookup_name_current_level
 243    instead.  */
 244
 245 struct GTY(()) cp_binding_level {
 246   /* A chain of _DECL nodes for all variables, constants, functions,
 247       and typedef types.  These are in the reverse of the order
 248       supplied.  There may be OVERLOADs on this list, too, but they
 249       are wrapped in TREE_LISTs; the TREE_VALUE is the OVERLOAD.  */
 250   tree names;
 251
 252   /* Using directives.  */
 253   vec<tree, va_gc> *using_directives;
 254
 255   /* For the binding level corresponding to a class, the entities
 256       declared in the class or its base classes.  */
 257   vec<cp_class_binding, va_gc> *class_shadowed;
 258
 259   /* Similar to class_shadowed, but for IDENTIFIER_TYPE_VALUE, and
 260       is used for all binding levels. The TREE_PURPOSE is the name of
 261       the entity, the TREE_TYPE is the associated type.  In addition
 262       the TREE_VALUE is the IDENTIFIER_TYPE_VALUE before we entered
 263       the class.  */
 264   tree type_shadowed;
 265
 266   /* For each level (except not the global one),
 267       a chain of BLOCK nodes for all the levels
 268       that were entered and exited one level down.  */
 269   tree blocks;
 270
 271   /* The entity (namespace, class, function) the scope of which this
 272       binding contour corresponds to.  Otherwise NULL.  */
 273   tree this_entity;
 274
 275   /* The binding level which this one is contained in (inherits from).  */
 276   cp_binding_level *level_chain;
 277
 278   /* STATEMENT_LIST for statements in this binding contour.
 279       Only used at present for SK_CLEANUP temporary bindings.  */
 280   tree statement_list;
 281
 282   /* Binding depth at which this level began.  */
 283   int binding_depth;
 284
 285   /* The kind of scope that this object represents.  However, a
 286       SK_TEMPLATE_SPEC scope is represented with KIND set to
 287       SK_TEMPLATE_PARMS and EXPLICIT_SPEC_P set to true.  */
 288   ENUM_BITFIELD (scope_kind) kind : 4;
 289
 290   /* True if this scope is an SK_TEMPLATE_SPEC scope.  This field is
 291       only valid if KIND == SK_TEMPLATE_PARMS.  */
 292   BOOL_BITFIELD explicit_spec_p : 1;
 293
 294   /* true means make a BLOCK for this level regardless of all else.  */
 295   unsigned keep : 1;
 296
 297   /* Nonzero if this level can safely have additional
 298       cleanup-needing variables added to it.  */
 299   unsigned more_cleanups_ok : 1;
 300   unsigned have_cleanups : 1;
 301
 302   /* Transient state set if this scope is of sk_class kind
 303      and is in the process of defining 'this_entity'.  Reset
 304      on leaving the class definition to allow for the scope
 305      to be subsequently re-used as a non-defining scope for
 306      'this_entity'.  */
 307   unsigned defining_class_p : 1;
 308
 309   /* true for SK_FUNCTION_PARMS of immediate functions.  */
 310   unsigned immediate_fn_ctx_p : 1;
 311
 312   /* 22 bits left to fill a 32-bit word.  */
 313 };
 314
 315 /* The binding level currently in effect.  */
 316
 317 #define current_binding_level                   \
 318   (*(cfun && cp_function_chain && cp_function_chain->bindings \
 319    ? &cp_function_chain->bindings               \
 320    : &scope_chain->bindings))
 321
 322 /* The binding level of the current class, if any.  */
 323
 324 #define class_binding_level scope_chain->class_bindings
 325
 326 /* True if SCOPE designates the global scope binding contour.  */
 327 #define global_scope_p(SCOPE) \
 328   ((SCOPE) == NAMESPACE_LEVEL (global_namespace))
 329
 330 extern cp_binding_level *leave_scope (void);
 331 extern bool kept_level_p (void);
 332 extern bool global_bindings_p (void);
 333 extern bool toplevel_bindings_p (void);
 334 extern bool namespace_bindings_p (void);
 335 extern bool local_bindings_p (void);
 336 extern bool template_parm_scope_p (void);
 337 extern scope_kind innermost_scope_kind (void);
 338 extern cp_binding_level *begin_scope (scope_kind, tree);
 339 extern void print_binding_stack (void);
 340 extern void pop_everything (void);
 341 extern void keep_next_level (bool);
 342 extern bool is_ancestor (tree ancestor, tree descendant);
 343 extern bool is_nested_namespace (tree parent, tree descendant,
 344                                  bool inline_only = false);
 345 extern tree push_scope (tree);
 346 extern void pop_scope (tree);
 347 extern tree push_inner_scope (tree);
 348 extern void pop_inner_scope (tree, tree);
 349 extern void push_binding_level (cp_binding_level *);
 350 \f
 351 extern bool handle_namespace_attrs (tree, tree);
 352 extern void pushlevel_class (void);
 353 extern void poplevel_class (void);
 354
 355 /* What kind of scopes name lookup looks in.  An enum class so we
 356    don't accidentally mix integers.  */
 357 enum class LOOK_where
 358 {
 359   BLOCK = 1 << 0,  /* Consider block scopes.  */
 360   CLASS = 1 << 1,  /* Consider class scopes.  */
 361   NAMESPACE = 1 << 2,  /* Consider namespace scopes.  */
 362
 363   ALL = BLOCK | CLASS | NAMESPACE,
 364   BLOCK_NAMESPACE = BLOCK | NAMESPACE,
 365   CLASS_NAMESPACE = CLASS | NAMESPACE,
 366 };
 367 constexpr LOOK_where operator| (LOOK_where a, LOOK_where b)
 368 {
 369   return LOOK_where (unsigned (a) | unsigned (b));
 370 }
 371 constexpr LOOK_where operator& (LOOK_where a, LOOK_where b)
 372 {
 373   return LOOK_where (unsigned (a) & unsigned (b));
 374 }
 375
 376 enum class LOOK_want
 377 {
 378   NORMAL = 0,  /* Normal lookup -- non-types can hide implicit types.  */
 379   TYPE = 1 << 1,  /* We only want TYPE_DECLS.  */
 380   NAMESPACE = 1 << 2,  /* We only want NAMESPACE_DECLS.  */
 381
 382   HIDDEN_FRIEND = 1 << 3, /* See hidden friends.  */
 383   HIDDEN_LAMBDA = 1 << 4,  /* See lambda-ignored entities.  */
 384
 385   TYPE_NAMESPACE = TYPE | NAMESPACE,  /* Either NAMESPACE or TYPE.  */
 386 };
 387 constexpr LOOK_want operator| (LOOK_want a, LOOK_want b)
 388 {
 389   return LOOK_want (unsigned (a) | unsigned (b));
 390 }
 391 constexpr LOOK_want operator& (LOOK_want a, LOOK_want b)
 392 {
 393   return LOOK_want (unsigned (a) & unsigned (b));
 394 }
 395
 396 extern tree lookup_name (tree, LOOK_where, LOOK_want = LOOK_want::NORMAL);
 397 /* Also declared in c-family/c-common.h.  */
 398 extern tree lookup_name (tree name);
 399 inline tree lookup_name (tree name, LOOK_want want)
 400 {
 401   return lookup_name (name, LOOK_where::ALL, want);
 402 }
 403
 404 enum class TAG_how
 405 {
 406   CURRENT_ONLY = 0, // Look and insert only in current scope
 407
 408   GLOBAL = 1, // Unqualified lookup, innermost-non-class insertion
 409
 410   INNERMOST_NON_CLASS = 2, // Look and insert only into
 411                            // innermost-non-class
 412
 413   HIDDEN_FRIEND = 3, // As INNERMOST_NON_CLASS, but hide it
 414 };
 415
 416 extern tree lookup_elaborated_type (tree, TAG_how);
 417 extern tree get_namespace_binding (tree ns, tree id);
 418 extern void set_global_binding (tree decl);
 419 inline tree get_global_binding (tree id)
 420 {
 421   return get_namespace_binding (NULL_TREE, id);
 422 }
 423 extern tree lookup_qualified_name (tree scope, tree name,
 424                                    LOOK_want = LOOK_want::NORMAL,
 425                                    bool = true);
 426 extern tree lookup_qualified_name (tree scope, const char *name,
 427                                    LOOK_want = LOOK_want::NORMAL,
 428                                    bool = true);
 429 extern bool pushdecl_class_level (tree);
 430 extern tree pushdecl_namespace_level (tree, bool hiding = false);
 431 extern bool push_class_level_binding (tree, tree);
 432 extern tree get_local_decls ();
 433 extern int function_parm_depth (void);
 434 extern tree cp_namespace_decls (tree);
 435 extern void set_decl_namespace (tree, tree, bool);
 436 extern void push_decl_namespace (tree);
 437 extern void pop_decl_namespace (void);
 438 extern void do_namespace_alias (tree, tree);
 439 extern tree do_class_using_decl (tree, tree);
 440 extern tree lookup_arg_dependent (tree, tree, vec<tree, va_gc> *);
 441 extern tree search_anon_aggr (tree, tree, bool = false);
 442 extern tree get_class_binding_direct (tree, tree, bool want_type = false);
 443 extern tree get_class_binding (tree, tree, bool want_type = false);
 444 extern tree *find_member_slot (tree klass, tree name);
 445 extern tree *add_member_slot (tree klass, tree name);
 446 extern void resort_type_member_vec (void *, void *,
 447                                     gt_pointer_operator, void *);
 448 extern vec<tree, va_gc> *set_class_bindings (tree, int extra = 0);
 449 extern void insert_late_enum_def_bindings (tree, tree);
 450 extern tree innermost_non_namespace_value (tree);
 451 extern cxx_binding *outer_binding (tree, cxx_binding *, bool);
 452 extern void cp_emit_debug_info_for_using (tree, tree);
 453
 454 extern void finish_nonmember_using_decl (tree scope, tree name);
 455 extern void finish_using_directive (tree target, tree attribs);
 456 void push_local_extern_decl_alias (tree decl);
 457 extern tree pushdecl (tree, bool hiding = false);
 458 extern tree pushdecl_outermost_localscope (tree);
 459 extern tree pushdecl_top_level (tree);
 460 extern tree pushdecl_top_level_and_finish (tree, tree);
 461 extern tree pushtag (tree, tree, TAG_how = TAG_how::CURRENT_ONLY);
 462 extern int push_namespace (tree, bool make_inline = false);
 463 extern void pop_namespace (void);
 464 extern void push_nested_namespace (tree);
 465 extern void pop_nested_namespace (tree);
 466 extern void push_to_top_level (void);
 467 extern void pop_from_top_level (void);
 468 extern void maybe_save_operator_binding (tree);
 469 extern void push_operator_bindings (void);
 470 extern void push_using_decl_bindings (tree, tree);
 471 extern void discard_operator_bindings (tree);
 472
 473 /* Lower level interface for modules. */
 474 extern tree *mergeable_namespace_slots (tree ns, tree name, bool is_global,
 475                                         tree *mvec);
 476 extern void add_mergeable_namespace_entity (tree *slot, tree decl);
 477 extern tree lookup_class_binding (tree ctx, tree name);
 478 extern bool import_module_binding (tree ctx, tree name, unsigned mod,
 479                                    unsigned snum);
 480 extern bool set_module_binding (tree ctx, tree name, unsigned mod,
 481                                 int mod_glob_flag,
 482                                 tree value, tree type, tree visible);
 483 extern void add_module_namespace_decl (tree ns, tree decl);
 484
 485 enum WMB_Flags
 486 {
 487   WMB_None = 0,
 488   WMB_Dups = 1 << 0,
 489   WMB_Export = 1 << 1,
 490   WMB_Using = 1 << 2,
 491   WMB_Hidden = 1 << 3,
 492 };
 493
 494 extern unsigned walk_module_binding (tree binding, bitmap partitions,
 495                                      bool (*)(tree decl, WMB_Flags, void *data),
 496                                      void *data);
 497 extern tree add_imported_namespace (tree ctx, tree name, location_t,
 498                                     unsigned module,
 499                                     bool inline_p, bool visible_p);
 500 extern const char *get_cxx_dialect_name (enum cxx_dialect dialect);
 501
 502 #endif /* GCC_CP_NAME_LOOKUP_H */