gcc/cp/parser.h

   1 /* Data structures and function exported by the C++ Parser.
   2    Copyright (C) 2010-2014 Free Software Foundation, Inc.
   3
   4    This file is part of GCC.
   5
   6    GCC is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3, or (at your option)
   9    any later version.
  10
  11    GCC is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef GCC_CP_PARSER_H
  21 #define GCC_CP_PARSER_H
  22
  23 #include "tree.h"
  24 #include "cp/cp-tree.h"
  25 #include "c-family/c-pragma.h"
  26
  27 /* A token's value and its associated deferred access checks and
  28    qualifying scope.  */
  29
  30 struct GTY(()) tree_check {
  31   /* The value associated with the token.  */
  32   tree value;
  33   /* The checks that have been associated with value.  */
  34   vec<deferred_access_check, va_gc> *checks;
  35   /* The token's qualifying scope (used when it is a
  36      CPP_NESTED_NAME_SPECIFIER).  */
  37   tree qualifying_scope;
  38 };
  39
  40 /* A C++ token.  */
  41
  42 typedef struct GTY (()) cp_token {
  43   /* The kind of token.  */
  44   ENUM_BITFIELD (cpp_ttype) type : 8;
  45   /* If this token is a keyword, this value indicates which keyword.
  46      Otherwise, this value is RID_MAX.  */
  47   ENUM_BITFIELD (rid) keyword : 8;
  48   /* Token flags.  */
  49   unsigned char flags;
  50   /* Identifier for the pragma.  */
  51   ENUM_BITFIELD (pragma_kind) pragma_kind : 6;
  52   /* True if this token is from a context where it is implicitly extern "C" */
  53   BOOL_BITFIELD implicit_extern_c : 1;
  54   /* True for a CPP_NAME token that is not a keyword (i.e., for which
  55      KEYWORD is RID_MAX) iff this name was looked up and found to be
  56      ambiguous.  An error has already been reported.  */
  57   BOOL_BITFIELD ambiguous_p : 1;
  58   /* True for a token that has been purged.  If a token is purged,
  59      it is no longer a valid token and it should be considered
  60      deleted.  */
  61   BOOL_BITFIELD purged_p : 1;
  62   /* The location at which this token was found.  */
  63   location_t location;
  64   /* The value associated with this token, if any.  */
  65   union cp_token_value {
  66     /* Used for CPP_NESTED_NAME_SPECIFIER and CPP_TEMPLATE_ID.  */
  67     struct tree_check* GTY((tag ("1"))) tree_check_value;
  68     /* Use for all other tokens.  */
  69     tree GTY((tag ("0"))) value;
  70   } GTY((desc ("(%1.type == CPP_TEMPLATE_ID) || (%1.type == CPP_NESTED_NAME_SPECIFIER)"))) u;
  71 } cp_token;
  72
  73
  74 /* We use a stack of token pointer for saving token sets.  */
  75 typedef struct cp_token *cp_token_position;
  76
  77 /* The cp_lexer structure represents the C++ lexer.  It is responsible
  78    for managing the token stream from the preprocessor and supplying
  79    it to the parser.  Tokens are never added to the cp_lexer after
  80    it is created.  */
  81
  82 typedef struct GTY (()) cp_lexer {
  83   /* The memory allocated for the buffer.  NULL if this lexer does not
  84      own the token buffer.  */
  85   vec<cp_token, va_gc> *buffer;
  86
  87   /* A pointer just past the last available token.  The tokens
  88      in this lexer are [buffer, last_token).  */
  89   cp_token_position GTY ((skip)) last_token;
  90
  91   /* The next available token.  If NEXT_TOKEN is &eof_token, then there are
  92      no more available tokens.  */
  93   cp_token_position GTY ((skip)) next_token;
  94
  95   /* A stack indicating positions at which cp_lexer_save_tokens was
  96      called.  The top entry is the most recent position at which we
  97      began saving tokens.  If the stack is non-empty, we are saving
  98      tokens.  */
  99   vec<cp_token_position> GTY ((skip)) saved_tokens;
 100
 101   /* The next lexer in a linked list of lexers.  */
 102   struct cp_lexer *next;
 103
 104   /* True if we should output debugging information.  */
 105   bool debugging_p;
 106
 107   /* True if we're in the context of parsing a pragma, and should not
 108      increment past the end-of-line marker.  */
 109   bool in_pragma;
 110 } cp_lexer;
 111
 112
 113 /* cp_token_cache is a range of tokens.  There is no need to represent
 114    allocate heap memory for it, since tokens are never removed from the
 115    lexer's array.  There is also no need for the GC to walk through
 116    a cp_token_cache, since everything in here is referenced through
 117    a lexer.  */
 118
 119 typedef struct GTY(()) cp_token_cache {
 120   /* The beginning of the token range.  */
 121   cp_token * GTY((skip)) first;
 122
 123   /* Points immediately after the last token in the range.  */
 124   cp_token * GTY ((skip)) last;
 125 } cp_token_cache;
 126
 127 typedef cp_token_cache *cp_token_cache_ptr;
 128
 129 struct cp_token_ident_d
 130 {
 131   unsigned int ident_len;
 132   const char *ident_str;
 133   unsigned int before_len;
 134   const char *before_str;
 135   unsigned int after_len;
 136   const char *after_str;
 137 };
 138
 139 typedef struct cp_token_ident_d cp_token_ident;
 140
 141 /* An entry in a queue of function arguments that require post-processing.  */
 142
 143 typedef struct GTY(()) cp_default_arg_entry_d {
 144   /* The current_class_type when we parsed this arg.  */
 145   tree class_type;
 146
 147   /* The function decl itself.  */
 148   tree decl;
 149 } cp_default_arg_entry;
 150
 151
 152 /* An entry in a stack for member functions of local classes.  */
 153
 154 typedef struct GTY(()) cp_unparsed_functions_entry_d {
 155   /* Functions with default arguments that require post-processing.
 156      Functions appear in this list in declaration order.  */
 157   vec<cp_default_arg_entry, va_gc> *funs_with_default_args;
 158
 159   /* Functions with defintions that require post-processing.  Functions
 160      appear in this list in declaration order.  */
 161   vec<tree, va_gc> *funs_with_definitions;
 162
 163   /* Non-static data members with initializers that require post-processing.
 164      FIELD_DECLs appear in this list in declaration order.  */
 165   vec<tree, va_gc> *nsdmis;
 166 } cp_unparsed_functions_entry;
 167
 168
 169 /* The status of a tentative parse.  */
 170
 171 typedef enum cp_parser_status_kind
 172 {
 173   /* No errors have occurred.  */
 174   CP_PARSER_STATUS_KIND_NO_ERROR,
 175   /* An error has occurred.  */
 176   CP_PARSER_STATUS_KIND_ERROR,
 177   /* We are committed to this tentative parse, whether or not an error
 178      has occurred.  */
 179   CP_PARSER_STATUS_KIND_COMMITTED
 180 } cp_parser_status_kind;
 181
 182
 183 /* Context that is saved and restored when parsing tentatively.  */
 184 typedef struct GTY (()) cp_parser_context {
 185   /* If this is a tentative parsing context, the status of the
 186      tentative parse.  */
 187   enum cp_parser_status_kind status;
 188   /* If non-NULL, we have just seen a `x->' or `x.' expression.  Names
 189      that are looked up in this context must be looked up both in the
 190      scope given by OBJECT_TYPE (the type of `x' or `*x') and also in
 191      the context of the containing expression.  */
 192   tree object_type;
 193
 194   /* The next parsing context in the stack.  */
 195   struct cp_parser_context *next;
 196 } cp_parser_context;
 197
 198
 199 /* Control structure for #pragma omp declare simd parsing.  */
 200 struct cp_omp_declare_simd_data {
 201   bool error_seen; /* Set if error has been reported.  */
 202   bool fndecl_seen; /* Set if one fn decl/definition has been seen already.  */
 203   vec<cp_token_cache_ptr> tokens;
 204 };
 205
 206
 207 /* The cp_parser structure represents the C++ parser.  */
 208
 209 typedef struct GTY(()) cp_parser {
 210   /* The lexer from which we are obtaining tokens.  */
 211   cp_lexer *lexer;
 212
 213   /* The scope in which names should be looked up.  If NULL_TREE, then
 214      we look up names in the scope that is currently open in the
 215      source program.  If non-NULL, this is either a TYPE or
 216      NAMESPACE_DECL for the scope in which we should look.  It can
 217      also be ERROR_MARK, when we've parsed a bogus scope.
 218
 219      This value is not cleared automatically after a name is looked
 220      up, so we must be careful to clear it before starting a new look
 221      up sequence.  (If it is not cleared, then `X::Y' followed by `Z'
 222      will look up `Z' in the scope of `X', rather than the current
 223      scope.)  Unfortunately, it is difficult to tell when name lookup
 224      is complete, because we sometimes peek at a token, look it up,
 225      and then decide not to consume it.   */
 226   tree scope;
 227
 228   /* OBJECT_SCOPE and QUALIFYING_SCOPE give the scopes in which the
 229      last lookup took place.  OBJECT_SCOPE is used if an expression
 230      like "x->y" or "x.y" was used; it gives the type of "*x" or "x",
 231      respectively.  QUALIFYING_SCOPE is used for an expression of the
 232      form "X::Y"; it refers to X.  */
 233   tree object_scope;
 234   tree qualifying_scope;
 235
 236   /* A stack of parsing contexts.  All but the bottom entry on the
 237      stack will be tentative contexts.
 238
 239      We parse tentatively in order to determine which construct is in
 240      use in some situations.  For example, in order to determine
 241      whether a statement is an expression-statement or a
 242      declaration-statement we parse it tentatively as a
 243      declaration-statement.  If that fails, we then reparse the same
 244      token stream as an expression-statement.  */
 245   cp_parser_context *context;
 246
 247   /* True if we are parsing GNU C++.  If this flag is not set, then
 248      GNU extensions are not recognized.  */
 249   bool allow_gnu_extensions_p;
 250
 251   /* TRUE if the `>' token should be interpreted as the greater-than
 252      operator.  FALSE if it is the end of a template-id or
 253      template-parameter-list. In C++0x mode, this flag also applies to
 254      `>>' tokens, which are viewed as two consecutive `>' tokens when
 255      this flag is FALSE.  */
 256   bool greater_than_is_operator_p;
 257
 258   /* TRUE if default arguments are allowed within a parameter list
 259      that starts at this point. FALSE if only a gnu extension makes
 260      them permissible.  */
 261   bool default_arg_ok_p;
 262
 263   /* TRUE if we are parsing an integral constant-expression.  See
 264      [expr.const] for a precise definition.  */
 265   bool integral_constant_expression_p;
 266
 267   /* TRUE if we are parsing an integral constant-expression -- but a
 268      non-constant expression should be permitted as well.  This flag
 269      is used when parsing an array bound so that GNU variable-length
 270      arrays are tolerated.  */
 271   bool allow_non_integral_constant_expression_p;
 272
 273   /* TRUE if ALLOW_NON_CONSTANT_EXPRESSION_P is TRUE and something has
 274      been seen that makes the expression non-constant.  */
 275   bool non_integral_constant_expression_p;
 276
 277   /* TRUE if local variable names and `this' are forbidden in the
 278      current context.  */
 279   bool local_variables_forbidden_p;
 280
 281   /* TRUE if the declaration we are parsing is part of a
 282      linkage-specification of the form `extern string-literal
 283      declaration'.  */
 284   bool in_unbraced_linkage_specification_p;
 285
 286   /* TRUE if we are presently parsing a declarator, after the
 287      direct-declarator.  */
 288   bool in_declarator_p;
 289
 290   /* TRUE if we are presently parsing a template-argument-list.  */
 291   bool in_template_argument_list_p;
 292
 293   /* Set to IN_ITERATION_STMT if parsing an iteration-statement,
 294      to IN_OMP_BLOCK if parsing OpenMP structured block and
 295      IN_OMP_FOR if parsing OpenMP loop.  If parsing a switch statement,
 296      this is bitwise ORed with IN_SWITCH_STMT, unless parsing an
 297      iteration-statement, OpenMP block or loop within that switch.  */
 298 #define IN_SWITCH_STMT          1
 299 #define IN_ITERATION_STMT       2
 300 #define IN_OMP_BLOCK            4
 301 #define IN_OMP_FOR              8
 302 #define IN_IF_STMT             16
 303 #define IN_CILK_SIMD_FOR       32
 304 #define IN_CILK_SPAWN          64
 305   unsigned char in_statement;
 306
 307   /* TRUE if we are presently parsing the body of a switch statement.
 308      Note that this doesn't quite overlap with in_statement above.
 309      The difference relates to giving the right sets of error messages:
 310      "case not in switch" vs "break statement used with OpenMP...".  */
 311   bool in_switch_statement_p;
 312
 313   /* TRUE if we are parsing a type-id in an expression context.  In
 314      such a situation, both "type (expr)" and "type (type)" are valid
 315      alternatives.  */
 316   bool in_type_id_in_expr_p;
 317
 318   /* TRUE if we are currently in a header file where declarations are
 319      implicitly extern "C".  */
 320   bool implicit_extern_c;
 321
 322   /* TRUE if strings in expressions should be translated to the execution
 323      character set.  */
 324   bool translate_strings_p;
 325
 326   /* TRUE if we are presently parsing the body of a function, but not
 327      a local class.  */
 328   bool in_function_body;
 329
 330   /* Nonzero if we're processing a __transaction_atomic or
 331      __transaction_relaxed statement.  */
 332   unsigned char in_transaction;
 333
 334   /* TRUE if we can auto-correct a colon to a scope operator.  */
 335   bool colon_corrects_to_scope_p;
 336
 337   /* TRUE if : doesn't start a class definition.  Should be only used
 338      together with type_definition_forbidden_message non-NULL, in
 339      contexts where new types may not be defined, and the type list
 340      is terminated by colon.  */
 341   bool colon_doesnt_start_class_def_p;
 342
 343   /* If non-NULL, then we are parsing a construct where new type
 344      definitions are not permitted.  The string stored here will be
 345      issued as an error message if a type is defined.  */
 346   const char *type_definition_forbidden_message;
 347
 348   /* A stack used for member functions of local classes.  The lists
 349      contained in an individual entry can only be processed once the
 350      outermost class being defined is complete.  */
 351   vec<cp_unparsed_functions_entry, va_gc> *unparsed_queues;
 352
 353   /* The number of classes whose definitions are currently in
 354      progress.  */
 355   unsigned num_classes_being_defined;
 356
 357   /* The number of template parameter lists that apply directly to the
 358      current declaration.  */
 359   unsigned num_template_parameter_lists;
 360
 361   /* When parsing #pragma omp declare simd, this is a pointer to a
 362      data structure with everything needed for parsing the clauses.  */
 363   cp_omp_declare_simd_data * GTY((skip)) omp_declare_simd;
 364
 365   /* When parsing the vector attribute in Cilk Plus SIMD-enabled function,
 366      this is a pointer to data structure with everything needed for parsing
 367      the clauses.  The cp_omp_declare_simd_data struct will hold all the
 368      necessary information, so creating another struct for this is not
 369      necessary.  */
 370   cp_omp_declare_simd_data * GTY((skip)) cilk_simd_fn_info;
 371
 372   /* Nonzero if parsing a parameter list where 'auto' should trigger an implicit
 373      template parameter.  */
 374   bool auto_is_implicit_function_template_parm_p;
 375
 376   /* TRUE if the function being declared was made a template due to its
 377      parameter list containing generic type specifiers (`auto' or concept
 378      identifiers) rather than an explicit template parameter list.  */
 379   bool fully_implicit_function_template_p;
 380
 381   /* Tracks the function's template parameter list when declaring a function
 382      using generic type parameters.  This is either a new chain in the case of a
 383      fully implicit function template or an extension of the function's existing
 384      template parameter list.  This is tracked to optimize calls subsequent
 385      calls to synthesize_implicit_template_parm during
 386      cp_parser_parameter_declaration.  */
 387   tree implicit_template_parms;
 388
 389   /* The scope into which an implicit template parameter list has been
 390      introduced or an existing template parameter list is being extended with
 391      implicit template paramaters.  In most cases this is the sk_function_parms
 392      scope containing the use of a generic type.  In the case of an out-of-line
 393      member definition using a generic type, it is the sk_class scope.  */
 394   cp_binding_level* implicit_template_scope;
 395
 396 } cp_parser;
 397
 398 /* In parser.c  */
 399 extern void debug (cp_token &ref);
 400 extern void debug (cp_token *ptr);
 401 extern void cp_lexer_debug_tokens (vec<cp_token, va_gc> *);
 402 extern void debug (vec<cp_token, va_gc> &ref);
 403 extern void debug (vec<cp_token, va_gc> *ptr);
 404 extern void cp_debug_parser (FILE *, cp_parser *);
 405 extern void debug (cp_parser &ref);
 406 extern void debug (cp_parser *ptr);
 407
 408 #endif  /* GCC_CP_PARSER_H  */