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 "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, va_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 73 /* We use a stack of token pointer for saving token sets. */ 74 typedef struct cp_token *cp_token_position; 75 76 /* The cp_lexer structure represents the C++ lexer. It is responsible 77 for managing the token stream from the preprocessor and supplying 78 it to the parser. Tokens are never added to the cp_lexer after 79 it is created. */ 80 81 typedef struct GTY (()) cp_lexer { 82 /* The memory allocated for the buffer. NULL if this lexer does not 83 own the token buffer. */ 84 vec<cp_token, va_gc> *buffer; 85 86 /* A pointer just past the last available token. The tokens 87 in this lexer are [buffer, last_token). */ 88 cp_token_position GTY ((skip)) last_token; 89 90 /* The next available token. If NEXT_TOKEN is &eof_token, then there are 91 no more available tokens. */ 92 cp_token_position GTY ((skip)) next_token; 93 94 /* A stack indicating positions at which cp_lexer_save_tokens was 95 called. The top entry is the most recent position at which we 96 began saving tokens. If the stack is non-empty, we are saving 97 tokens. */ 98 vec<cp_token_position> GTY ((skip)) saved_tokens; 99 100 /* The next lexer in a linked list of lexers. */ 101 struct cp_lexer *next; 102 103 /* True if we should output debugging information. */ 104 bool debugging_p; 105 106 /* True if we're in the context of parsing a pragma, and should not 107 increment past the end-of-line marker. */ 108 bool in_pragma; 109 } cp_lexer; 110 111 112 /* cp_token_cache is a range of tokens. There is no need to represent 113 allocate heap memory for it, since tokens are never removed from the 114 lexer's array. There is also no need for the GC to walk through 115 a cp_token_cache, since everything in here is referenced through 116 a lexer. */ 117 118 typedef struct GTY(()) cp_token_cache { 119 /* The beginning of the token range. */ 120 cp_token * GTY((skip)) first; 121 122 /* Points immediately after the last token in the range. */ 123 cp_token * GTY ((skip)) last; 124 } cp_token_cache; 125 126 typedef cp_token_cache *cp_token_cache_ptr; 127 128 struct cp_token_ident_d 129 { 130 unsigned int ident_len; 131 const char *ident_str; 132 unsigned int before_len; 133 const char *before_str; 134 unsigned int after_len; 135 const char *after_str; 136 }; 137 138 typedef struct cp_token_ident_d cp_token_ident; 139 140 /* An entry in a queue of function arguments that require post-processing. */ 141 142 typedef struct GTY(()) cp_default_arg_entry_d { 143 /* The current_class_type when we parsed this arg. */ 144 tree class_type; 145 146 /* The function decl itself. */ 147 tree decl; 148 } cp_default_arg_entry; 149 150 151 /* An entry in a stack for member functions of local classes. */ 152 153 typedef struct GTY(()) cp_unparsed_functions_entry_d { 154 /* Functions with default arguments that require post-processing. 155 Functions appear in this list in declaration order. */ 156 vec<cp_default_arg_entry, va_gc> *funs_with_default_args; 157 158 /* Functions with defintions that require post-processing. Functions 159 appear in this list in declaration order. */ 160 vec<tree, va_gc> *funs_with_definitions; 161 162 /* Non-static data members with initializers that require post-processing. 163 FIELD_DECLs appear in this list in declaration order. */ 164 vec<tree, va_gc> *nsdmis; 165 } cp_unparsed_functions_entry; 166 167 168 /* The status of a tentative parse. */ 169 170 typedef enum cp_parser_status_kind 171 { 172 /* No errors have occurred. */ 173 CP_PARSER_STATUS_KIND_NO_ERROR, 174 /* An error has occurred. */ 175 CP_PARSER_STATUS_KIND_ERROR, 176 /* We are committed to this tentative parse, whether or not an error 177 has occurred. */ 178 CP_PARSER_STATUS_KIND_COMMITTED 179 } cp_parser_status_kind; 180 181 182 /* Context that is saved and restored when parsing tentatively. */ 183 typedef struct GTY (()) cp_parser_context { 184 /* If this is a tentative parsing context, the status of the 185 tentative parse. */ 186 enum cp_parser_status_kind status; 187 /* If non-NULL, we have just seen a `x->' or `x.' expression. Names 188 that are looked up in this context must be looked up both in the 189 scope given by OBJECT_TYPE (the type of `x' or `*x') and also in 190 the context of the containing expression. */ 191 tree object_type; 192 193 /* The next parsing context in the stack. */ 194 struct cp_parser_context *next; 195 } cp_parser_context; 196 197 198 /* The cp_parser structure represents the C++ parser. */ 199 200 typedef struct GTY(()) cp_parser { 201 /* The lexer from which we are obtaining tokens. */ 202 cp_lexer *lexer; 203 204 /* The scope in which names should be looked up. If NULL_TREE, then 205 we look up names in the scope that is currently open in the 206 source program. If non-NULL, this is either a TYPE or 207 NAMESPACE_DECL for the scope in which we should look. It can 208 also be ERROR_MARK, when we've parsed a bogus scope. 209 210 This value is not cleared automatically after a name is looked 211 up, so we must be careful to clear it before starting a new look 212 up sequence. (If it is not cleared, then `X::Y' followed by `Z' 213 will look up `Z' in the scope of `X', rather than the current 214 scope.) Unfortunately, it is difficult to tell when name lookup 215 is complete, because we sometimes peek at a token, look it up, 216 and then decide not to consume it. */ 217 tree scope; 218 219 /* OBJECT_SCOPE and QUALIFYING_SCOPE give the scopes in which the 220 last lookup took place. OBJECT_SCOPE is used if an expression 221 like "x->y" or "x.y" was used; it gives the type of "*x" or "x", 222 respectively. QUALIFYING_SCOPE is used for an expression of the 223 form "X::Y"; it refers to X. */ 224 tree object_scope; 225 tree qualifying_scope; 226 227 /* A stack of parsing contexts. All but the bottom entry on the 228 stack will be tentative contexts. 229 230 We parse tentatively in order to determine which construct is in 231 use in some situations. For example, in order to determine 232 whether a statement is an expression-statement or a 233 declaration-statement we parse it tentatively as a 234 declaration-statement. If that fails, we then reparse the same 235 token stream as an expression-statement. */ 236 cp_parser_context *context; 237 238 /* True if we are parsing GNU C++. If this flag is not set, then 239 GNU extensions are not recognized. */ 240 bool allow_gnu_extensions_p; 241 242 /* TRUE if the `>' token should be interpreted as the greater-than 243 operator. FALSE if it is the end of a template-id or 244 template-parameter-list. In C++0x mode, this flag also applies to 245 `>>' tokens, which are viewed as two consecutive `>' tokens when 246 this flag is FALSE. */ 247 bool greater_than_is_operator_p; 248 249 /* TRUE if default arguments are allowed within a parameter list 250 that starts at this point. FALSE if only a gnu extension makes 251 them permissible. */ 252 bool default_arg_ok_p; 253 254 /* TRUE if we are parsing an integral constant-expression. See 255 [expr.const] for a precise definition. */ 256 bool integral_constant_expression_p; 257 258 /* TRUE if we are parsing an integral constant-expression -- but a 259 non-constant expression should be permitted as well. This flag 260 is used when parsing an array bound so that GNU variable-length 261 arrays are tolerated. */ 262 bool allow_non_integral_constant_expression_p; 263 264 /* TRUE if ALLOW_NON_CONSTANT_EXPRESSION_P is TRUE and something has 265 been seen that makes the expression non-constant. */ 266 bool non_integral_constant_expression_p; 267 268 /* TRUE if local variable names and `this' are forbidden in the 269 current context. */ 270 bool local_variables_forbidden_p; 271 272 /* TRUE if the declaration we are parsing is part of a 273 linkage-specification of the form `extern string-literal 274 declaration'. */ 275 bool in_unbraced_linkage_specification_p; 276 277 /* TRUE if we are presently parsing a declarator, after the 278 direct-declarator. */ 279 bool in_declarator_p; 280 281 /* TRUE if we are presently parsing a template-argument-list. */ 282 bool in_template_argument_list_p; 283 284 /* Set to IN_ITERATION_STMT if parsing an iteration-statement, 285 to IN_OMP_BLOCK if parsing OpenMP structured block and 286 IN_OMP_FOR if parsing OpenMP loop. If parsing a switch statement, 287 this is bitwise ORed with IN_SWITCH_STMT, unless parsing an 288 iteration-statement, OpenMP block or loop within that switch. */ 289 #define IN_SWITCH_STMT 1 290 #define IN_ITERATION_STMT 2 291 #define IN_OMP_BLOCK 4 292 #define IN_OMP_FOR 8 293 #define IN_IF_STMT 16 294 unsigned char in_statement; 295 296 /* TRUE if we are presently parsing the body of a switch statement. 297 Note that this doesn't quite overlap with in_statement above. 298 The difference relates to giving the right sets of error messages: 299 "case not in switch" vs "break statement used with OpenMP...". */ 300 bool in_switch_statement_p; 301 302 /* TRUE if we are parsing a type-id in an expression context. In 303 such a situation, both "type (expr)" and "type (type)" are valid 304 alternatives. */ 305 bool in_type_id_in_expr_p; 306 307 /* TRUE if we are currently in a header file where declarations are 308 implicitly extern "C". */ 309 bool implicit_extern_c; 310 311 /* TRUE if strings in expressions should be translated to the execution 312 character set. */ 313 bool translate_strings_p; 314 315 /* TRUE if we are presently parsing the body of a function, but not 316 a local class. */ 317 bool in_function_body; 318 319 /* Nonzero if we're processing a __transaction_atomic or 320 __transaction_relaxed statement. */ 321 unsigned char in_transaction; 322 323 /* TRUE if we can auto-correct a colon to a scope operator. */ 324 bool colon_corrects_to_scope_p; 325 326 /* If non-NULL, then we are parsing a construct where new type 327 definitions are not permitted. The string stored here will be 328 issued as an error message if a type is defined. */ 329 const char *type_definition_forbidden_message; 330 331 /* A stack used for member functions of local classes. The lists 332 contained in an individual entry can only be processed once the 333 outermost class being defined is complete. */ 334 vec<cp_unparsed_functions_entry, va_gc> *unparsed_queues; 335 336 /* The number of classes whose definitions are currently in 337 progress. */ 338 unsigned num_classes_being_defined; 339 340 /* The number of template parameter lists that apply directly to the 341 current declaration. */ 342 unsigned num_template_parameter_lists; 343 } cp_parser; 344 345 /* In parser.c */ 346 extern void cp_lexer_debug_tokens (vec<cp_token, va_gc> *); 347 extern void cp_debug_parser (FILE *, cp_parser *); 348 349 #endif /* GCC_CP_PARSER_H */ 350