gcc/cp/parser.h

   1 /* Data structures and function exported by the C++ Parser.
   2    Copyright (C) 2010 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 "c-family/c-pragma.h"
  25
  26 /* A token's value and its associated deferred access checks and
  27    qualifying scope.  */
  28
  29 struct GTY(()) tree_check {
  30   /* The value associated with the token.  */
  31   tree value;
  32   /* The checks that have been associated with value.  */
  33   VEC (deferred_access_check, gc)* checks;
  34   /* The token's qualifying scope (used when it is a
  35      CPP_NESTED_NAME_SPECIFIER).  */
  36   tree qualifying_scope;
  37 };
  38
  39 /* A C++ token.  */
  40
  41 typedef struct GTY (()) cp_token {
  42   /* The kind of token.  */
  43   ENUM_BITFIELD (cpp_ttype) type : 8;
  44   /* If this token is a keyword, this value indicates which keyword.
  45      Otherwise, this value is RID_MAX.  */
  46   ENUM_BITFIELD (rid) keyword : 8;
  47   /* Token flags.  */
  48   unsigned char flags;
  49   /* Identifier for the pragma.  */
  50   ENUM_BITFIELD (pragma_kind) pragma_kind : 6;
  51   /* True if this token is from a context where it is implicitly extern "C" */
  52   BOOL_BITFIELD implicit_extern_c : 1;
  53   /* True for a CPP_NAME token that is not a keyword (i.e., for which
  54      KEYWORD is RID_MAX) iff this name was looked up and found to be
  55      ambiguous.  An error has already been reported.  */
  56   BOOL_BITFIELD ambiguous_p : 1;
  57   /* True for a token that has been purged.  If a token is purged,
  58      it is no longer a valid token and it should be considered
  59      deleted.  */
  60   BOOL_BITFIELD purged_p : 1;
  61   /* The location at which this token was found.  */
  62   location_t location;
  63   /* The value associated with this token, if any.  */
  64   union cp_token_value {
  65     /* Used for CPP_NESTED_NAME_SPECIFIER and CPP_TEMPLATE_ID.  */
  66     struct tree_check* GTY((tag ("1"))) tree_check_value;
  67     /* Use for all other tokens.  */
  68     tree GTY((tag ("0"))) value;
  69   } GTY((desc ("(%1.type == CPP_TEMPLATE_ID) || (%1.type == CPP_NESTED_NAME_SPECIFIER)"))) u;
  70 } cp_token;
  71
  72 DEF_VEC_O (cp_token);
  73 DEF_VEC_ALLOC_O (cp_token,gc);
  74 DEF_VEC_ALLOC_O (cp_token,heap);
  75
  76 /* We use a stack of token pointer for saving token sets.  */
  77 typedef struct cp_token *cp_token_position;
  78 DEF_VEC_P (cp_token_position);
  79 DEF_VEC_ALLOC_P (cp_token_position,heap);
  80
  81 /* The cp_lexer structure represents the C++ lexer.  It is responsible
  82    for managing the token stream from the preprocessor and supplying
  83    it to the parser.  Tokens are never added to the cp_lexer after
  84    it is created.  */
  85
  86 typedef struct GTY (()) cp_lexer {
  87   /* The memory allocated for the buffer.  NULL if this lexer does not
  88      own the token buffer.  */
  89   VEC(cp_token,gc) *buffer;
  90
  91   /* A pointer just past the last available token.  The tokens
  92      in this lexer are [buffer, last_token).  */
  93   cp_token_position GTY ((skip)) last_token;
  94
  95   /* The next available token.  If NEXT_TOKEN is &eof_token, then there are
  96      no more available tokens.  */
  97   cp_token_position GTY ((skip)) next_token;
  98
  99   /* A stack indicating positions at which cp_lexer_save_tokens was
 100      called.  The top entry is the most recent position at which we
 101      began saving tokens.  If the stack is non-empty, we are saving
 102      tokens.  */
 103   VEC(cp_token_position,heap) *GTY ((skip)) saved_tokens;
 104
 105   /* The next lexer in a linked list of lexers.  */
 106   struct cp_lexer *next;
 107
 108   /* True if we should output debugging information.  */
 109   bool debugging_p;
 110
 111   /* True if we're in the context of parsing a pragma, and should not
 112      increment past the end-of-line marker.  */
 113   bool in_pragma;
 114 } cp_lexer;
 115
 116 DEF_VEC_O (cp_lexer);
 117 DEF_VEC_ALLOC_O (cp_lexer,heap);
 118
 119 /* cp_token_cache is a range of tokens.  There is no need to represent
 120    allocate heap memory for it, since tokens are never removed from the
 121    lexer's array.  There is also no need for the GC to walk through
 122    a cp_token_cache, since everything in here is referenced through
 123    a lexer.  */
 124
 125 typedef struct GTY(()) cp_token_cache {
 126   /* The beginning of the token range.  */
 127   cp_token * GTY((skip)) first;
 128
 129   /* Points immediately after the last token in the range.  */
 130   cp_token * GTY ((skip)) last;
 131 } cp_token_cache;
 132
 133 typedef cp_token_cache *cp_token_cache_ptr;
 134 DEF_VEC_P (cp_token_cache_ptr);
 135 DEF_VEC_ALLOC_P (cp_token_cache_ptr,gc);
 136
 137 struct cp_token_ident_d
 138 {
 139   unsigned int ident_len;
 140   const char *ident_str;
 141   unsigned int before_len;
 142   const char *before_str;
 143   unsigned int after_len;
 144   const char *after_str;
 145 };
 146
 147 typedef struct cp_token_ident_d cp_token_ident;
 148
 149 /* An entry in a queue of function arguments that require post-processing.  */
 150
 151 typedef struct GTY(()) cp_default_arg_entry_d {
 152   /* The current_class_type when we parsed this arg.  */
 153   tree class_type;
 154
 155   /* The function decl itself.  */
 156   tree decl;
 157 } cp_default_arg_entry;
 158
 159 DEF_VEC_O(cp_default_arg_entry);
 160 DEF_VEC_ALLOC_O(cp_default_arg_entry,gc);
 161
 162 /* An entry in a stack for member functions of local classes.  */
 163
 164 typedef struct GTY(()) cp_unparsed_functions_entry_d {
 165   /* Functions with default arguments that require post-processing.
 166      Functions appear in this list in declaration order.  */
 167   VEC(cp_default_arg_entry,gc) *funs_with_default_args;
 168
 169   /* Functions with defintions that require post-processing.  Functions
 170      appear in this list in declaration order.  */
 171   VEC(tree,gc) *funs_with_definitions;
 172 } cp_unparsed_functions_entry;
 173
 174 DEF_VEC_O(cp_unparsed_functions_entry);
 175 DEF_VEC_ALLOC_O(cp_unparsed_functions_entry,gc);
 176
 177 /* The status of a tentative parse.  */
 178
 179 typedef enum cp_parser_status_kind
 180 {
 181   /* No errors have occurred.  */
 182   CP_PARSER_STATUS_KIND_NO_ERROR,
 183   /* An error has occurred.  */
 184   CP_PARSER_STATUS_KIND_ERROR,
 185   /* We are committed to this tentative parse, whether or not an error
 186      has occurred.  */
 187   CP_PARSER_STATUS_KIND_COMMITTED
 188 } cp_parser_status_kind;
 189
 190
 191 /* Context that is saved and restored when parsing tentatively.  */
 192 typedef struct GTY (()) cp_parser_context {
 193   /* If this is a tentative parsing context, the status of the
 194      tentative parse.  */
 195   enum cp_parser_status_kind status;
 196   /* If non-NULL, we have just seen a `x->' or `x.' expression.  Names
 197      that are looked up in this context must be looked up both in the
 198      scope given by OBJECT_TYPE (the type of `x' or `*x') and also in
 199      the context of the containing expression.  */
 200   tree object_type;
 201
 202   /* The next parsing context in the stack.  */
 203   struct cp_parser_context *next;
 204 } cp_parser_context;
 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   unsigned char in_statement;
 304
 305   /* TRUE if we are presently parsing the body of a switch statement.
 306      Note that this doesn't quite overlap with in_statement above.
 307      The difference relates to giving the right sets of error messages:
 308      "case not in switch" vs "break statement used with OpenMP...".  */
 309   bool in_switch_statement_p;
 310
 311   /* TRUE if we are parsing a type-id in an expression context.  In
 312      such a situation, both "type (expr)" and "type (type)" are valid
 313      alternatives.  */
 314   bool in_type_id_in_expr_p;
 315
 316   /* TRUE if we are currently in a header file where declarations are
 317      implicitly extern "C".  */
 318   bool implicit_extern_c;
 319
 320   /* TRUE if strings in expressions should be translated to the execution
 321      character set.  */
 322   bool translate_strings_p;
 323
 324   /* TRUE if we are presently parsing the body of a function, but not
 325      a local class.  */
 326   bool in_function_body;
 327
 328   /* TRUE if we can auto-correct a colon to a scope operator.  */
 329   bool colon_corrects_to_scope_p;
 330
 331   /* If non-NULL, then we are parsing a construct where new type
 332      definitions are not permitted.  The string stored here will be
 333      issued as an error message if a type is defined.  */
 334   const char *type_definition_forbidden_message;
 335
 336   /* A stack used for member functions of local classes.  The lists
 337      contained in an individual entry can only be processed once the
 338      outermost class being defined is complete.  */
 339   VEC(cp_unparsed_functions_entry,gc) *unparsed_queues;
 340
 341   /* The number of classes whose definitions are currently in
 342      progress.  */
 343   unsigned num_classes_being_defined;
 344
 345   /* The number of template parameter lists that apply directly to the
 346      current declaration.  */
 347   unsigned num_template_parameter_lists;
 348 } cp_parser;
 349
 350 /* In parser.c  */
 351 #ifdef ENABLE_CHECKING
 352 extern void cp_lexer_dump_tokens (FILE *, VEC(cp_token,gc) *, unsigned);
 353 extern void cp_lexer_debug_tokens (VEC(cp_token,gc) *);
 354 #endif
 355
 356 #endif  /* GCC_CP_PARSER_H  */