gcc/cp/parser.h

   1 /* Data structures and function exported by the C++ Parser.
   2    Copyright (C) 2010-2015 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 if an error has already been reported for this token, such as a
  55      CPP_NAME token that is not a keyword (i.e., for which KEYWORD is
  56      RID_MAX) iff this name was looked up and found to be ambiguous.  */
  57   BOOL_BITFIELD error_reported : 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 defined within their 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
 167   /* Nested classes go in this vector, so that we can do some final
 168      processing after parsing any NSDMIs.  */
 169   vec<tree, va_gc> *classes;
 170 } cp_unparsed_functions_entry;
 171
 172
 173 /* The status of a tentative parse.  */
 174
 175 typedef enum cp_parser_status_kind
 176 {
 177   /* No errors have occurred.  */
 178   CP_PARSER_STATUS_KIND_NO_ERROR,
 179   /* An error has occurred.  */
 180   CP_PARSER_STATUS_KIND_ERROR,
 181   /* We are committed to this tentative parse, whether or not an error
 182      has occurred.  */
 183   CP_PARSER_STATUS_KIND_COMMITTED
 184 } cp_parser_status_kind;
 185
 186
 187 /* Context that is saved and restored when parsing tentatively.  */
 188 typedef struct GTY (()) cp_parser_context {
 189   /* If this is a tentative parsing context, the status of the
 190      tentative parse.  */
 191   enum cp_parser_status_kind status;
 192   /* If non-NULL, we have just seen a `x->' or `x.' expression.  Names
 193      that are looked up in this context must be looked up both in the
 194      scope given by OBJECT_TYPE (the type of `x' or `*x') and also in
 195      the context of the containing expression.  */
 196   tree object_type;
 197
 198   /* The next parsing context in the stack.  */
 199   struct cp_parser_context *next;
 200 } cp_parser_context;
 201
 202
 203 /* Control structure for #pragma omp declare simd parsing.  */
 204 struct cp_omp_declare_simd_data {
 205   bool error_seen; /* Set if error has been reported.  */
 206   bool fndecl_seen; /* Set if one fn decl/definition has been seen already.  */
 207   vec<cp_token_cache_ptr> tokens;
 208 };
 209
 210
 211 /* The cp_parser structure represents the C++ parser.  */
 212
 213 typedef struct GTY(()) cp_parser {
 214   /* The lexer from which we are obtaining tokens.  */
 215   cp_lexer *lexer;
 216
 217   /* The scope in which names should be looked up.  If NULL_TREE, then
 218      we look up names in the scope that is currently open in the
 219      source program.  If non-NULL, this is either a TYPE or
 220      NAMESPACE_DECL for the scope in which we should look.  It can
 221      also be ERROR_MARK, when we've parsed a bogus scope.
 222
 223      This value is not cleared automatically after a name is looked
 224      up, so we must be careful to clear it before starting a new look
 225      up sequence.  (If it is not cleared, then `X::Y' followed by `Z'
 226      will look up `Z' in the scope of `X', rather than the current
 227      scope.)  Unfortunately, it is difficult to tell when name lookup
 228      is complete, because we sometimes peek at a token, look it up,
 229      and then decide not to consume it.   */
 230   tree scope;
 231
 232   /* OBJECT_SCOPE and QUALIFYING_SCOPE give the scopes in which the
 233      last lookup took place.  OBJECT_SCOPE is used if an expression
 234      like "x->y" or "x.y" was used; it gives the type of "*x" or "x",
 235      respectively.  QUALIFYING_SCOPE is used for an expression of the
 236      form "X::Y"; it refers to X.  */
 237   tree object_scope;
 238   tree qualifying_scope;
 239
 240   /* A stack of parsing contexts.  All but the bottom entry on the
 241      stack will be tentative contexts.
 242
 243      We parse tentatively in order to determine which construct is in
 244      use in some situations.  For example, in order to determine
 245      whether a statement is an expression-statement or a
 246      declaration-statement we parse it tentatively as a
 247      declaration-statement.  If that fails, we then reparse the same
 248      token stream as an expression-statement.  */
 249   cp_parser_context *context;
 250
 251   /* True if we are parsing GNU C++.  If this flag is not set, then
 252      GNU extensions are not recognized.  */
 253   bool allow_gnu_extensions_p;
 254
 255   /* TRUE if the `>' token should be interpreted as the greater-than
 256      operator.  FALSE if it is the end of a template-id or
 257      template-parameter-list. In C++0x mode, this flag also applies to
 258      `>>' tokens, which are viewed as two consecutive `>' tokens when
 259      this flag is FALSE.  */
 260   bool greater_than_is_operator_p;
 261
 262   /* TRUE if default arguments are allowed within a parameter list
 263      that starts at this point. FALSE if only a gnu extension makes
 264      them permissible.  */
 265   bool default_arg_ok_p;
 266
 267   /* TRUE if we are parsing an integral constant-expression.  See
 268      [expr.const] for a precise definition.  */
 269   bool integral_constant_expression_p;
 270
 271   /* TRUE if we are parsing an integral constant-expression -- but a
 272      non-constant expression should be permitted as well.  This flag
 273      is used when parsing an array bound so that GNU variable-length
 274      arrays are tolerated.  */
 275   bool allow_non_integral_constant_expression_p;
 276
 277   /* TRUE if ALLOW_NON_CONSTANT_EXPRESSION_P is TRUE and something has
 278      been seen that makes the expression non-constant.  */
 279   bool non_integral_constant_expression_p;
 280
 281   /* TRUE if local variable names and `this' are forbidden in the
 282      current context.  */
 283   bool local_variables_forbidden_p;
 284
 285   /* TRUE if the declaration we are parsing is part of a
 286      linkage-specification of the form `extern string-literal
 287      declaration'.  */
 288   bool in_unbraced_linkage_specification_p;
 289
 290   /* TRUE if we are presently parsing a declarator, after the
 291      direct-declarator.  */
 292   bool in_declarator_p;
 293
 294   /* TRUE if we are presently parsing a template-argument-list.  */
 295   bool in_template_argument_list_p;
 296
 297   /* Set to IN_ITERATION_STMT if parsing an iteration-statement,
 298      to IN_OMP_BLOCK if parsing OpenMP structured block and
 299      IN_OMP_FOR if parsing OpenMP loop.  If parsing a switch statement,
 300      this is bitwise ORed with IN_SWITCH_STMT, unless parsing an
 301      iteration-statement, OpenMP block or loop within that switch.  */
 302 #define IN_SWITCH_STMT          1
 303 #define IN_ITERATION_STMT       2
 304 #define IN_OMP_BLOCK            4
 305 #define IN_OMP_FOR              8
 306 #define IN_IF_STMT             16
 307 #define IN_CILK_SIMD_FOR       32
 308 #define IN_CILK_SPAWN          64
 309   unsigned char in_statement;
 310
 311   /* TRUE if we are presently parsing the body of a switch statement.
 312      Note that this doesn't quite overlap with in_statement above.
 313      The difference relates to giving the right sets of error messages:
 314      "case not in switch" vs "break statement used with OpenMP...".  */
 315   bool in_switch_statement_p;
 316
 317   /* TRUE if we are parsing a type-id in an expression context.  In
 318      such a situation, both "type (expr)" and "type (type)" are valid
 319      alternatives.  */
 320   bool in_type_id_in_expr_p;
 321
 322   /* TRUE if we are currently in a header file where declarations are
 323      implicitly extern "C".  */
 324   bool implicit_extern_c;
 325
 326   /* TRUE if strings in expressions should be translated to the execution
 327      character set.  */
 328   bool translate_strings_p;
 329
 330   /* TRUE if we are presently parsing the body of a function, but not
 331      a local class.  */
 332   bool in_function_body;
 333
 334   /* Nonzero if we're processing a __transaction_atomic or
 335      __transaction_relaxed statement.  */
 336   unsigned char in_transaction;
 337
 338   /* TRUE if we can auto-correct a colon to a scope operator.  */
 339   bool colon_corrects_to_scope_p;
 340
 341   /* TRUE if : doesn't start a class definition.  Should be only used
 342      together with type_definition_forbidden_message non-NULL, in
 343      contexts where new types may not be defined, and the type list
 344      is terminated by colon.  */
 345   bool colon_doesnt_start_class_def_p;
 346
 347   /* If non-NULL, then we are parsing a construct where new type
 348      definitions are not permitted.  The string stored here will be
 349      issued as an error message if a type is defined.  */
 350   const char *type_definition_forbidden_message;
 351
 352   /* A stack used for member functions of local classes.  The lists
 353      contained in an individual entry can only be processed once the
 354      outermost class being defined is complete.  */
 355   vec<cp_unparsed_functions_entry, va_gc> *unparsed_queues;
 356
 357   /* The number of classes whose definitions are currently in
 358      progress.  */
 359   unsigned num_classes_being_defined;
 360
 361   /* The number of template parameter lists that apply directly to the
 362      current declaration.  */
 363   unsigned num_template_parameter_lists;
 364
 365   /* When parsing #pragma omp declare simd, this is a pointer to a
 366      data structure with everything needed for parsing the clauses.  */
 367   cp_omp_declare_simd_data * GTY((skip)) omp_declare_simd;
 368
 369   /* When parsing the vector attribute in Cilk Plus SIMD-enabled function,
 370      this is a pointer to data structure with everything needed for parsing
 371      the clauses.  The cp_omp_declare_simd_data struct will hold all the
 372      necessary information, so creating another struct for this is not
 373      necessary.  */
 374   cp_omp_declare_simd_data * GTY((skip)) cilk_simd_fn_info;
 375
 376   /* Nonzero if parsing a parameter list where 'auto' should trigger an implicit
 377      template parameter.  */
 378   bool auto_is_implicit_function_template_parm_p;
 379
 380   /* TRUE if the function being declared was made a template due to its
 381      parameter list containing generic type specifiers (`auto' or concept
 382      identifiers) rather than an explicit template parameter list.  */
 383   bool fully_implicit_function_template_p;
 384
 385   /* Tracks the function's template parameter list when declaring a function
 386      using generic type parameters.  This is either a new chain in the case of a
 387      fully implicit function template or an extension of the function's existing
 388      template parameter list.  This is tracked to optimize calls subsequent
 389      calls to synthesize_implicit_template_parm during
 390      cp_parser_parameter_declaration.  */
 391   tree implicit_template_parms;
 392
 393   /* The scope into which an implicit template parameter list has been
 394      introduced or an existing template parameter list is being extended with
 395      implicit template paramaters.  In most cases this is the sk_function_parms
 396      scope containing the use of a generic type.  In the case of an out-of-line
 397      member definition using a generic type, it is the sk_class scope.  */
 398   cp_binding_level* implicit_template_scope;
 399
 400 } cp_parser;
 401
 402 /* In parser.c  */
 403 extern void debug (cp_token &ref);
 404 extern void debug (cp_token *ptr);
 405 extern void cp_lexer_debug_tokens (vec<cp_token, va_gc> *);
 406 extern void debug (vec<cp_token, va_gc> &ref);
 407 extern void debug (vec<cp_token, va_gc> *ptr);
 408 extern void cp_debug_parser (FILE *, cp_parser *);
 409 extern void debug (cp_parser &ref);
 410 extern void debug (cp_parser *ptr);
 411
 412 #endif  /* GCC_CP_PARSER_H  */