1 /* Data structures and function exported by the C++ Parser. 2 Copyright (C) 2010-2020 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 struct GTY (()) cp_token { 43 /* The kind of token. */ 44 enum 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 rid keyword : 8; 48 /* Token flags. */ 49 unsigned char flags; 50 /* True if this token is from a context where it is implicitly extern "C" */ 51 bool implicit_extern_c : 1; 52 /* True if an error has already been reported for this token, such as a 53 CPP_NAME token that is not a keyword (i.e., for which KEYWORD is 54 RID_MAX) iff this name was looked up and found to be ambiguous. */ 55 bool error_reported : 1; 56 /* True for a token that has been purged. If a token is purged, 57 it is no longer a valid token and it should be considered 58 deleted. */ 59 bool purged_p : 1; 60 bool tree_check_p : 1; 61 /* 4 unused bits. */ 62 63 /* The location at which this token was found. */ 64 location_t location; 65 /* The value associated with this token, if any. */ 66 union cp_token_value { 67 /* Used for compound tokens such as CPP_NESTED_NAME_SPECIFIER. */ 68 struct tree_check* GTY((tag ("true"))) tree_check_value; 69 /* Use for all other tokens. */ 70 tree GTY((tag ("false"))) value; 71 } GTY((desc ("%1.tree_check_p"))) u; 72 }; 73 74 75 /* We use a stack of token pointer for saving token sets. */ 76 typedef struct cp_token *cp_token_position; 77 78 /* The cp_lexer structure represents the C++ lexer. It is responsible 79 for managing the token stream from the preprocessor and supplying 80 it to the parser. Tokens are never added to the cp_lexer after 81 it is created. */ 82 83 struct GTY (()) cp_lexer { 84 /* The memory allocated for the buffer. NULL if this lexer does not 85 own the token buffer. */ 86 vec<cp_token, va_gc> *buffer; 87 88 /* A pointer just past the last available token. The tokens 89 in this lexer are [buffer, last_token). */ 90 cp_token_position GTY ((skip)) last_token; 91 92 /* The next available token. If NEXT_TOKEN is &eof_token, then there are 93 no more available tokens. */ 94 cp_token_position GTY ((skip)) next_token; 95 96 /* A stack indicating positions at which cp_lexer_save_tokens was 97 called. The top entry is the most recent position at which we 98 began saving tokens. If the stack is non-empty, we are saving 99 tokens. */ 100 vec<cp_token_position> GTY ((skip)) saved_tokens; 101 102 /* Saved pieces of end token we replaced with the eof token. */ 103 enum cpp_ttype saved_type : 8; 104 enum rid saved_keyword : 8; 105 106 /* The next lexer in a linked list of lexers. */ 107 struct cp_lexer *next; 108 109 /* True if we should output debugging information. */ 110 bool debugging_p; 111 112 /* True if we're in the context of parsing a pragma, and should not 113 increment past the end-of-line marker. */ 114 bool in_pragma; 115 }; 116 117 118 /* cp_token_cache is a range of tokens. There is no need to represent 119 allocate heap memory for it, since tokens are never removed from the 120 lexer's array. There is also no need for the GC to walk through 121 a cp_token_cache, since everything in here is referenced through 122 a lexer. */ 123 124 struct GTY(()) cp_token_cache { 125 /* The beginning of the token range. */ 126 cp_token * GTY((skip)) first; 127 128 /* Points immediately after the last token in the range. */ 129 cp_token * GTY ((skip)) last; 130 }; 131 132 typedef cp_token_cache *cp_token_cache_ptr; 133 134 struct cp_token_ident 135 { 136 unsigned int ident_len; 137 const char *ident_str; 138 unsigned int before_len; 139 const char *before_str; 140 unsigned int after_len; 141 const char *after_str; 142 }; 143 144 /* An entry in a queue of function arguments that require post-processing. */ 145 146 struct GTY(()) cp_default_arg_entry { 147 /* The current_class_type when we parsed this arg. */ 148 tree class_type; 149 150 /* The function decl itself. */ 151 tree decl; 152 }; 153 154 155 /* An entry in a stack for member functions defined within their classes. */ 156 157 struct GTY(()) cp_unparsed_functions_entry { 158 /* Functions with default arguments that require post-processing. 159 Functions appear in this list in declaration order. */ 160 vec<cp_default_arg_entry, va_gc> *funs_with_default_args; 161 162 /* Functions with defintions that require post-processing. Functions 163 appear in this list in declaration order. */ 164 vec<tree, va_gc> *funs_with_definitions; 165 166 /* Non-static data members with initializers that require post-processing. 167 FIELD_DECLs appear in this list in declaration order. */ 168 vec<tree, va_gc> *nsdmis; 169 170 /* Functions with noexcept-specifiers that require post-processing. */ 171 vec<tree, va_gc> *noexcepts; 172 }; 173 174 175 /* The status of a tentative parse. */ 176 177 enum cp_parser_status_kind 178 { 179 /* No errors have occurred. */ 180 CP_PARSER_STATUS_KIND_NO_ERROR, 181 /* An error has occurred. */ 182 CP_PARSER_STATUS_KIND_ERROR, 183 /* We are committed to this tentative parse, whether or not an error 184 has occurred. */ 185 CP_PARSER_STATUS_KIND_COMMITTED 186 }; 187 188 189 /* Context that is saved and restored when parsing tentatively. */ 190 struct GTY (()) cp_parser_context { 191 /* If this is a tentative parsing context, the status of the 192 tentative parse. */ 193 enum cp_parser_status_kind status; 194 /* If non-NULL, we have just seen a `x->' or `x.' expression. Names 195 that are looked up in this context must be looked up both in the 196 scope given by OBJECT_TYPE (the type of `x' or `*x') and also in 197 the context of the containing expression. */ 198 tree object_type; 199 200 /* The next parsing context in the stack. */ 201 struct cp_parser_context *next; 202 }; 203 204 205 /* Helper data structure for parsing #pragma omp declare {simd,variant}. */ 206 struct cp_omp_declare_simd_data { 207 bool error_seen; /* Set if error has been reported. */ 208 bool fndecl_seen; /* Set if one fn decl/definition has been seen already. */ 209 bool variant_p; /* Set for #pragma omp declare variant. */ 210 vec<cp_token_cache_ptr> tokens; 211 tree clauses; 212 }; 213 214 /* Helper data structure for parsing #pragma acc routine. */ 215 struct cp_oacc_routine_data : cp_omp_declare_simd_data { 216 location_t loc; 217 }; 218 219 /* The cp_parser structure represents the C++ parser. */ 220 221 struct GTY(()) cp_parser { 222 /* The lexer from which we are obtaining tokens. */ 223 cp_lexer *lexer; 224 225 /* The scope in which names should be looked up. If NULL_TREE, then 226 we look up names in the scope that is currently open in the 227 source program. If non-NULL, this is either a TYPE or 228 NAMESPACE_DECL for the scope in which we should look. It can 229 also be ERROR_MARK, when we've parsed a bogus scope. 230 231 This value is not cleared automatically after a name is looked 232 up, so we must be careful to clear it before starting a new look 233 up sequence. (If it is not cleared, then `X::Y' followed by `Z' 234 will look up `Z' in the scope of `X', rather than the current 235 scope.) Unfortunately, it is difficult to tell when name lookup 236 is complete, because we sometimes peek at a token, look it up, 237 and then decide not to consume it. */ 238 tree scope; 239 240 /* OBJECT_SCOPE and QUALIFYING_SCOPE give the scopes in which the 241 last lookup took place. OBJECT_SCOPE is used if an expression 242 like "x->y" or "x.y" was used; it gives the type of "*x" or "x", 243 respectively. QUALIFYING_SCOPE is used for an expression of the 244 form "X::Y"; it refers to X. */ 245 tree object_scope; 246 tree qualifying_scope; 247 248 /* A stack of parsing contexts. All but the bottom entry on the 249 stack will be tentative contexts. 250 251 We parse tentatively in order to determine which construct is in 252 use in some situations. For example, in order to determine 253 whether a statement is an expression-statement or a 254 declaration-statement we parse it tentatively as a 255 declaration-statement. If that fails, we then reparse the same 256 token stream as an expression-statement. */ 257 cp_parser_context *context; 258 259 /* True if we are parsing GNU C++. If this flag is not set, then 260 GNU extensions are not recognized. */ 261 bool allow_gnu_extensions_p; 262 263 /* TRUE if the `>' token should be interpreted as the greater-than 264 operator. FALSE if it is the end of a template-id or 265 template-parameter-list. In C++0x mode, this flag also applies to 266 `>>' tokens, which are viewed as two consecutive `>' tokens when 267 this flag is FALSE. */ 268 bool greater_than_is_operator_p; 269 270 /* TRUE if default arguments are allowed within a parameter list 271 that starts at this point. FALSE if only a gnu extension makes 272 them permissible. */ 273 bool default_arg_ok_p; 274 275 /* TRUE if we are parsing an integral constant-expression. See 276 [expr.const] for a precise definition. */ 277 bool integral_constant_expression_p; 278 279 /* TRUE if we are parsing an integral constant-expression -- but a 280 non-constant expression should be permitted as well. This flag 281 is used when parsing an array bound so that GNU variable-length 282 arrays are tolerated. */ 283 bool allow_non_integral_constant_expression_p; 284 285 /* TRUE if ALLOW_NON_CONSTANT_EXPRESSION_P is TRUE and something has 286 been seen that makes the expression non-constant. */ 287 bool non_integral_constant_expression_p; 288 289 /* Used to track if local variable names and/or `this' are forbidden 290 in the current context. */ 291 #define LOCAL_VARS_FORBIDDEN (1 << 0) 292 #define THIS_FORBIDDEN (1 << 1) 293 #define LOCAL_VARS_AND_THIS_FORBIDDEN (LOCAL_VARS_FORBIDDEN | THIS_FORBIDDEN) 294 unsigned char local_variables_forbidden_p; 295 296 /* TRUE if the declaration we are parsing is part of a 297 linkage-specification of the form `extern string-literal 298 declaration'. */ 299 bool in_unbraced_linkage_specification_p; 300 301 /* TRUE if we are presently parsing a declarator, after the 302 direct-declarator. */ 303 bool in_declarator_p; 304 305 /* TRUE if we are presently parsing a template-argument-list. */ 306 bool in_template_argument_list_p; 307 308 /* Set to IN_ITERATION_STMT if parsing an iteration-statement, 309 to IN_OMP_BLOCK if parsing OpenMP structured block and 310 IN_OMP_FOR if parsing OpenMP loop. If parsing a switch statement, 311 this is bitwise ORed with IN_SWITCH_STMT, unless parsing an 312 iteration-statement, OpenMP block or loop within that switch. */ 313 #define IN_SWITCH_STMT 1 314 #define IN_ITERATION_STMT 2 315 #define IN_OMP_BLOCK 4 316 #define IN_OMP_FOR 8 317 #define IN_IF_STMT 16 318 unsigned char in_statement; 319 320 /* TRUE if we are presently parsing the body of a switch statement. 321 Note that this doesn't quite overlap with in_statement above. 322 The difference relates to giving the right sets of error messages: 323 "case not in switch" vs "break statement used with OpenMP...". */ 324 bool in_switch_statement_p; 325 326 /* TRUE if we are parsing a type-id in an expression context. In 327 such a situation, both "type (expr)" and "type (type)" are valid 328 alternatives. */ 329 bool in_type_id_in_expr_p; 330 331 /* TRUE if strings in expressions should be translated to the execution 332 character set. */ 333 bool translate_strings_p; 334 335 /* TRUE if we are presently parsing the body of a function, but not 336 a local class. */ 337 bool in_function_body; 338 339 /* Nonzero if we're processing a __transaction_atomic or 340 __transaction_relaxed statement. */ 341 unsigned char in_transaction; 342 343 /* TRUE if we can auto-correct a colon to a scope operator. */ 344 bool colon_corrects_to_scope_p; 345 346 /* TRUE if : doesn't start a class definition. Should be only used 347 together with type_definition_forbidden_message non-NULL, in 348 contexts where new types may not be defined, and the type list 349 is terminated by colon. */ 350 bool colon_doesnt_start_class_def_p; 351 352 /* TRUE if we are parsing an objective c message, and ':' is permitted 353 to terminate an assignment-expression. */ 354 bool objective_c_message_context_p; 355 356 /* If non-NULL, then we are parsing a construct where new type 357 definitions are not permitted. The string stored here will be 358 issued as an error message if a type is defined. */ 359 const char *type_definition_forbidden_message; 360 361 /* Argument for type_definition_forbidden_message if needed. */ 362 const char *type_definition_forbidden_message_arg; 363 364 /* A stack used for member functions of local classes. The lists 365 contained in an individual entry can only be processed once the 366 outermost class being defined is complete. */ 367 vec<cp_unparsed_functions_entry, va_gc> *unparsed_queues; 368 369 /* The number of classes whose definitions are currently in 370 progress. */ 371 unsigned num_classes_being_defined; 372 373 /* The number of template parameter lists that apply directly to the 374 current declaration. */ 375 unsigned num_template_parameter_lists; 376 377 /* When parsing #pragma omp declare simd, this is a pointer to a 378 helper data structure. */ 379 cp_omp_declare_simd_data * GTY((skip)) omp_declare_simd; 380 381 /* When parsing #pragma acc routine, this is a pointer to a helper data 382 structure. */ 383 cp_oacc_routine_data * GTY((skip)) oacc_routine; 384 385 /* Nonzero if parsing a parameter list where 'auto' should trigger an implicit 386 template parameter. */ 387 bool auto_is_implicit_function_template_parm_p; 388 389 /* TRUE if the function being declared was made a template due to its 390 parameter list containing generic type specifiers (`auto' or concept 391 identifiers) rather than an explicit template parameter list. */ 392 bool fully_implicit_function_template_p; 393 394 /* Tracks the function's template parameter list when declaring a function 395 using generic type parameters. This is either a new chain in the case of a 396 fully implicit function template or an extension of the function's existing 397 template parameter list. This is tracked to optimize calls subsequent 398 calls to synthesize_implicit_template_parm during 399 cp_parser_parameter_declaration. */ 400 tree implicit_template_parms; 401 402 /* The scope into which an implicit template parameter list has been 403 introduced or an existing template parameter list is being extended with 404 implicit template parameters. In most cases this is the sk_function_parms 405 scope containing the use of a generic type. In the case of an out-of-line 406 member definition using a generic type, it is the sk_class scope. */ 407 cp_binding_level* implicit_template_scope; 408 409 /* True if parsing a result type in a compound requirement. This permits 410 constrained-type-specifiers inside what would normally be a trailing 411 return type. */ 412 bool in_result_type_constraint_p; 413 414 /* True if a constrained-type-specifier is not allowed in this 415 context e.g., because they could never be deduced. */ 416 int prevent_constrained_type_specifiers; 417 418 /* Location of the string-literal token within the current linkage 419 specification, if any, or UNKNOWN_LOCATION otherwise. */ 420 location_t innermost_linkage_specification_location; 421 422 }; 423 424 /* In parser.c */ 425 extern void debug (cp_token &ref); 426 extern void debug (cp_token *ptr); 427 extern void cp_lexer_debug_tokens (vec<cp_token, va_gc> *); 428 extern void debug (vec<cp_token, va_gc> &ref); 429 extern void debug (vec<cp_token, va_gc> *ptr); 430 extern void cp_debug_parser (FILE *, cp_parser *); 431 extern void debug (cp_parser &ref); 432 extern void debug (cp_parser *ptr); 433 extern bool cp_keyword_starts_decl_specifier_p (enum rid keyword); 434 435 #endif /* GCC_CP_PARSER_H */ 436