gcc/cp/parser.h

   1 /* Data structures and function exported by the C++ Parser.
   2    Copyright (C) 2010-2013 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 /* The cp_parser structure represents the C++ parser.  */
 200
 201 typedef struct GTY(()) cp_parser {
 202   /* The lexer from which we are obtaining tokens.  */
 203   cp_lexer *lexer;
 204
 205   /* The scope in which names should be looked up.  If NULL_TREE, then
 206      we look up names in the scope that is currently open in the
 207      source program.  If non-NULL, this is either a TYPE or
 208      NAMESPACE_DECL for the scope in which we should look.  It can
 209      also be ERROR_MARK, when we've parsed a bogus scope.
 210
 211      This value is not cleared automatically after a name is looked
 212      up, so we must be careful to clear it before starting a new look
 213      up sequence.  (If it is not cleared, then `X::Y' followed by `Z'
 214      will look up `Z' in the scope of `X', rather than the current
 215      scope.)  Unfortunately, it is difficult to tell when name lookup
 216      is complete, because we sometimes peek at a token, look it up,
 217      and then decide not to consume it.   */
 218   tree scope;
 219
 220   /* OBJECT_SCOPE and QUALIFYING_SCOPE give the scopes in which the
 221      last lookup took place.  OBJECT_SCOPE is used if an expression
 222      like "x->y" or "x.y" was used; it gives the type of "*x" or "x",
 223      respectively.  QUALIFYING_SCOPE is used for an expression of the
 224      form "X::Y"; it refers to X.  */
 225   tree object_scope;
 226   tree qualifying_scope;
 227
 228   /* A stack of parsing contexts.  All but the bottom entry on the
 229      stack will be tentative contexts.
 230
 231      We parse tentatively in order to determine which construct is in
 232      use in some situations.  For example, in order to determine
 233      whether a statement is an expression-statement or a
 234      declaration-statement we parse it tentatively as a
 235      declaration-statement.  If that fails, we then reparse the same
 236      token stream as an expression-statement.  */
 237   cp_parser_context *context;
 238
 239   /* True if we are parsing GNU C++.  If this flag is not set, then
 240      GNU extensions are not recognized.  */
 241   bool allow_gnu_extensions_p;
 242
 243   /* TRUE if the `>' token should be interpreted as the greater-than
 244      operator.  FALSE if it is the end of a template-id or
 245      template-parameter-list. In C++0x mode, this flag also applies to
 246      `>>' tokens, which are viewed as two consecutive `>' tokens when
 247      this flag is FALSE.  */
 248   bool greater_than_is_operator_p;
 249
 250   /* TRUE if default arguments are allowed within a parameter list
 251      that starts at this point. FALSE if only a gnu extension makes
 252      them permissible.  */
 253   bool default_arg_ok_p;
 254
 255   /* TRUE if we are parsing an integral constant-expression.  See
 256      [expr.const] for a precise definition.  */
 257   bool integral_constant_expression_p;
 258
 259   /* TRUE if we are parsing an integral constant-expression -- but a
 260      non-constant expression should be permitted as well.  This flag
 261      is used when parsing an array bound so that GNU variable-length
 262      arrays are tolerated.  */
 263   bool allow_non_integral_constant_expression_p;
 264
 265   /* TRUE if ALLOW_NON_CONSTANT_EXPRESSION_P is TRUE and something has
 266      been seen that makes the expression non-constant.  */
 267   bool non_integral_constant_expression_p;
 268
 269   /* TRUE if local variable names and `this' are forbidden in the
 270      current context.  */
 271   bool local_variables_forbidden_p;
 272
 273   /* TRUE if the declaration we are parsing is part of a
 274      linkage-specification of the form `extern string-literal
 275      declaration'.  */
 276   bool in_unbraced_linkage_specification_p;
 277
 278   /* TRUE if we are presently parsing a declarator, after the
 279      direct-declarator.  */
 280   bool in_declarator_p;
 281
 282   /* TRUE if we are presently parsing a template-argument-list.  */
 283   bool in_template_argument_list_p;
 284
 285   /* Set to IN_ITERATION_STMT if parsing an iteration-statement,
 286      to IN_OMP_BLOCK if parsing OpenMP structured block and
 287      IN_OMP_FOR if parsing OpenMP loop.  If parsing a switch statement,
 288      this is bitwise ORed with IN_SWITCH_STMT, unless parsing an
 289      iteration-statement, OpenMP block or loop within that switch.  */
 290 #define IN_SWITCH_STMT          1
 291 #define IN_ITERATION_STMT       2
 292 #define IN_OMP_BLOCK            4
 293 #define IN_OMP_FOR              8
 294 #define IN_IF_STMT             16
 295   unsigned char in_statement;
 296
 297   /* TRUE if we are presently parsing the body of a switch statement.
 298      Note that this doesn't quite overlap with in_statement above.
 299      The difference relates to giving the right sets of error messages:
 300      "case not in switch" vs "break statement used with OpenMP...".  */
 301   bool in_switch_statement_p;
 302
 303   /* TRUE if we are parsing a type-id in an expression context.  In
 304      such a situation, both "type (expr)" and "type (type)" are valid
 305      alternatives.  */
 306   bool in_type_id_in_expr_p;
 307
 308   /* TRUE if we are currently in a header file where declarations are
 309      implicitly extern "C".  */
 310   bool implicit_extern_c;
 311
 312   /* TRUE if strings in expressions should be translated to the execution
 313      character set.  */
 314   bool translate_strings_p;
 315
 316   /* TRUE if we are presently parsing the body of a function, but not
 317      a local class.  */
 318   bool in_function_body;
 319
 320   /* Nonzero if we're processing a __transaction_atomic or
 321      __transaction_relaxed statement.  */
 322   unsigned char in_transaction;
 323
 324   /* TRUE if we can auto-correct a colon to a scope operator.  */
 325   bool colon_corrects_to_scope_p;
 326
 327   /* If non-NULL, then we are parsing a construct where new type
 328      definitions are not permitted.  The string stored here will be
 329      issued as an error message if a type is defined.  */
 330   const char *type_definition_forbidden_message;
 331
 332   /* A stack used for member functions of local classes.  The lists
 333      contained in an individual entry can only be processed once the
 334      outermost class being defined is complete.  */
 335   vec<cp_unparsed_functions_entry, va_gc> *unparsed_queues;
 336
 337   /* The number of classes whose definitions are currently in
 338      progress.  */
 339   unsigned num_classes_being_defined;
 340
 341   /* The number of template parameter lists that apply directly to the
 342      current declaration.  */
 343   unsigned num_template_parameter_lists;
 344 } cp_parser;
 345
 346 /* In parser.c  */
 347 extern void debug (cp_token &ref);
 348 extern void debug (cp_token *ptr);
 349 extern void cp_lexer_debug_tokens (vec<cp_token, va_gc> *);
 350 extern void debug (vec<cp_token, va_gc> &ref);
 351 extern void debug (vec<cp_token, va_gc> *ptr);
 352 extern void cp_debug_parser (FILE *, cp_parser *);
 353 extern void debug (cp_parser &ref);
 354 extern void debug (cp_parser *ptr);
 355
 356 #endif  /* GCC_CP_PARSER_H  */