1 /* Data structures and function exported by the C++ Parser. 2 Copyright (C) 2010-2019 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_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 /* True if this token is from a context where it is implicitly extern "C" */ 51 BOOL_BITFIELD 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_BITFIELD 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_BITFIELD purged_p : 1; 60 /* 5 unused bits. */ 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 compound tokens such as CPP_NESTED_NAME_SPECIFIER. */ 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)" 70 "|| (%1.type == CPP_NESTED_NAME_SPECIFIER)" 71 "|| (%1.type == CPP_DECLTYPE)"))) 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 /* The next lexer in a linked list of lexers. */ 103 struct cp_lexer *next; 104 105 /* True if we should output debugging information. */ 106 bool debugging_p; 107 108 /* True if we're in the context of parsing a pragma, and should not 109 increment past the end-of-line marker. */ 110 bool in_pragma; 111 }; 112 113 114 /* cp_token_cache is a range of tokens. There is no need to represent 115 allocate heap memory for it, since tokens are never removed from the 116 lexer's array. There is also no need for the GC to walk through 117 a cp_token_cache, since everything in here is referenced through 118 a lexer. */ 119 120 struct GTY(()) cp_token_cache { 121 /* The beginning of the token range. */ 122 cp_token * GTY((skip)) first; 123 124 /* Points immediately after the last token in the range. */ 125 cp_token * GTY ((skip)) last; 126 }; 127 128 typedef cp_token_cache *cp_token_cache_ptr; 129 130 struct cp_token_ident 131 { 132 unsigned int ident_len; 133 const char *ident_str; 134 unsigned int before_len; 135 const char *before_str; 136 unsigned int after_len; 137 const char *after_str; 138 }; 139 140 /* An entry in a queue of function arguments that require post-processing. */ 141 142 struct GTY(()) cp_default_arg_entry { 143 /* The current_class_type when we parsed this arg. */ 144 tree class_type; 145 146 /* The function decl itself. */ 147 tree decl; 148 }; 149 150 151 /* An entry in a stack for member functions defined within their classes. */ 152 153 struct GTY(()) cp_unparsed_functions_entry { 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; 165 166 /* Nested classes go in this vector, so that we can do some final 167 processing after parsing any NSDMIs. */ 168 vec<tree, va_gc> *classes; 169 }; 170 171 172 /* The status of a tentative parse. */ 173 174 enum cp_parser_status_kind 175 { 176 /* No errors have occurred. */ 177 CP_PARSER_STATUS_KIND_NO_ERROR, 178 /* An error has occurred. */ 179 CP_PARSER_STATUS_KIND_ERROR, 180 /* We are committed to this tentative parse, whether or not an error 181 has occurred. */ 182 CP_PARSER_STATUS_KIND_COMMITTED 183 }; 184 185 186 /* Context that is saved and restored when parsing tentatively. */ 187 struct GTY (()) cp_parser_context { 188 /* If this is a tentative parsing context, the status of the 189 tentative parse. */ 190 enum cp_parser_status_kind status; 191 /* If non-NULL, we have just seen a `x->' or `x.' expression. Names 192 that are looked up in this context must be looked up both in the 193 scope given by OBJECT_TYPE (the type of `x' or `*x') and also in 194 the context of the containing expression. */ 195 tree object_type; 196 197 /* The next parsing context in the stack. */ 198 struct cp_parser_context *next; 199 }; 200 201 202 /* Helper data structure for parsing #pragma omp declare simd. */ 203 struct cp_omp_declare_simd_data { 204 bool error_seen; /* Set if error has been reported. */ 205 bool fndecl_seen; /* Set if one fn decl/definition has been seen already. */ 206 vec<cp_token_cache_ptr> tokens; 207 tree clauses; 208 }; 209 210 /* Helper data structure for parsing #pragma acc routine. */ 211 struct cp_oacc_routine_data : cp_omp_declare_simd_data { 212 location_t loc; 213 }; 214 215 /* The cp_parser structure represents the C++ parser. */ 216 217 struct GTY(()) cp_parser { 218 /* The lexer from which we are obtaining tokens. */ 219 cp_lexer *lexer; 220 221 /* The scope in which names should be looked up. If NULL_TREE, then 222 we look up names in the scope that is currently open in the 223 source program. If non-NULL, this is either a TYPE or 224 NAMESPACE_DECL for the scope in which we should look. It can 225 also be ERROR_MARK, when we've parsed a bogus scope. 226 227 This value is not cleared automatically after a name is looked 228 up, so we must be careful to clear it before starting a new look 229 up sequence. (If it is not cleared, then `X::Y' followed by `Z' 230 will look up `Z' in the scope of `X', rather than the current 231 scope.) Unfortunately, it is difficult to tell when name lookup 232 is complete, because we sometimes peek at a token, look it up, 233 and then decide not to consume it. */ 234 tree scope; 235 236 /* OBJECT_SCOPE and QUALIFYING_SCOPE give the scopes in which the 237 last lookup took place. OBJECT_SCOPE is used if an expression 238 like "x->y" or "x.y" was used; it gives the type of "*x" or "x", 239 respectively. QUALIFYING_SCOPE is used for an expression of the 240 form "X::Y"; it refers to X. */ 241 tree object_scope; 242 tree qualifying_scope; 243 244 /* A stack of parsing contexts. All but the bottom entry on the 245 stack will be tentative contexts. 246 247 We parse tentatively in order to determine which construct is in 248 use in some situations. For example, in order to determine 249 whether a statement is an expression-statement or a 250 declaration-statement we parse it tentatively as a 251 declaration-statement. If that fails, we then reparse the same 252 token stream as an expression-statement. */ 253 cp_parser_context *context; 254 255 /* True if we are parsing GNU C++. If this flag is not set, then 256 GNU extensions are not recognized. */ 257 bool allow_gnu_extensions_p; 258 259 /* TRUE if the `>' token should be interpreted as the greater-than 260 operator. FALSE if it is the end of a template-id or 261 template-parameter-list. In C++0x mode, this flag also applies to 262 `>>' tokens, which are viewed as two consecutive `>' tokens when 263 this flag is FALSE. */ 264 bool greater_than_is_operator_p; 265 266 /* TRUE if default arguments are allowed within a parameter list 267 that starts at this point. FALSE if only a gnu extension makes 268 them permissible. */ 269 bool default_arg_ok_p; 270 271 /* TRUE if we are parsing an integral constant-expression. See 272 [expr.const] for a precise definition. */ 273 bool integral_constant_expression_p; 274 275 /* TRUE if we are parsing an integral constant-expression -- but a 276 non-constant expression should be permitted as well. This flag 277 is used when parsing an array bound so that GNU variable-length 278 arrays are tolerated. */ 279 bool allow_non_integral_constant_expression_p; 280 281 /* TRUE if ALLOW_NON_CONSTANT_EXPRESSION_P is TRUE and something has 282 been seen that makes the expression non-constant. */ 283 bool non_integral_constant_expression_p; 284 285 /* Used to track if local variable names and/or `this' are forbidden 286 in the current context. */ 287 #define LOCAL_VARS_FORBIDDEN (1 << 0) 288 #define THIS_FORBIDDEN (1 << 1) 289 #define LOCAL_VARS_AND_THIS_FORBIDDEN (LOCAL_VARS_FORBIDDEN | THIS_FORBIDDEN) 290 unsigned char local_variables_forbidden_p; 291 292 /* TRUE if the declaration we are parsing is part of a 293 linkage-specification of the form `extern string-literal 294 declaration'. */ 295 bool in_unbraced_linkage_specification_p; 296 297 /* TRUE if we are presently parsing a declarator, after the 298 direct-declarator. */ 299 bool in_declarator_p; 300 301 /* TRUE if we are presently parsing a template-argument-list. */ 302 bool in_template_argument_list_p; 303 304 /* Set to IN_ITERATION_STMT if parsing an iteration-statement, 305 to IN_OMP_BLOCK if parsing OpenMP structured block and 306 IN_OMP_FOR if parsing OpenMP loop. If parsing a switch statement, 307 this is bitwise ORed with IN_SWITCH_STMT, unless parsing an 308 iteration-statement, OpenMP block or loop within that switch. */ 309 #define IN_SWITCH_STMT 1 310 #define IN_ITERATION_STMT 2 311 #define IN_OMP_BLOCK 4 312 #define IN_OMP_FOR 8 313 #define IN_IF_STMT 16 314 unsigned char in_statement; 315 316 /* TRUE if we are presently parsing the body of a switch statement. 317 Note that this doesn't quite overlap with in_statement above. 318 The difference relates to giving the right sets of error messages: 319 "case not in switch" vs "break statement used with OpenMP...". */ 320 bool in_switch_statement_p; 321 322 /* TRUE if we are parsing a type-id in an expression context. In 323 such a situation, both "type (expr)" and "type (type)" are valid 324 alternatives. */ 325 bool in_type_id_in_expr_p; 326 327 /* TRUE if strings in expressions should be translated to the execution 328 character set. */ 329 bool translate_strings_p; 330 331 /* TRUE if we are presently parsing the body of a function, but not 332 a local class. */ 333 bool in_function_body; 334 335 /* Nonzero if we're processing a __transaction_atomic or 336 __transaction_relaxed statement. */ 337 unsigned char in_transaction; 338 339 /* TRUE if we can auto-correct a colon to a scope operator. */ 340 bool colon_corrects_to_scope_p; 341 342 /* TRUE if : doesn't start a class definition. Should be only used 343 together with type_definition_forbidden_message non-NULL, in 344 contexts where new types may not be defined, and the type list 345 is terminated by colon. */ 346 bool colon_doesnt_start_class_def_p; 347 348 /* If non-NULL, then we are parsing a construct where new type 349 definitions are not permitted. The string stored here will be 350 issued as an error message if a type is defined. */ 351 const char *type_definition_forbidden_message; 352 353 /* Argument for type_definition_forbidden_message if needed. */ 354 const char *type_definition_forbidden_message_arg; 355 356 /* A stack used for member functions of local classes. The lists 357 contained in an individual entry can only be processed once the 358 outermost class being defined is complete. */ 359 vec<cp_unparsed_functions_entry, va_gc> *unparsed_queues; 360 361 /* The number of classes whose definitions are currently in 362 progress. */ 363 unsigned num_classes_being_defined; 364 365 /* The number of template parameter lists that apply directly to the 366 current declaration. */ 367 unsigned num_template_parameter_lists; 368 369 /* When parsing #pragma omp declare simd, this is a pointer to a 370 helper data structure. */ 371 cp_omp_declare_simd_data * GTY((skip)) omp_declare_simd; 372 373 /* When parsing #pragma acc routine, this is a pointer to a helper data 374 structure. */ 375 cp_oacc_routine_data * GTY((skip)) oacc_routine; 376 377 /* Nonzero if parsing a parameter list where 'auto' should trigger an implicit 378 template parameter. */ 379 bool auto_is_implicit_function_template_parm_p; 380 381 /* TRUE if the function being declared was made a template due to its 382 parameter list containing generic type specifiers (`auto' or concept 383 identifiers) rather than an explicit template parameter list. */ 384 bool fully_implicit_function_template_p; 385 386 /* Tracks the function's template parameter list when declaring a function 387 using generic type parameters. This is either a new chain in the case of a 388 fully implicit function template or an extension of the function's existing 389 template parameter list. This is tracked to optimize calls subsequent 390 calls to synthesize_implicit_template_parm during 391 cp_parser_parameter_declaration. */ 392 tree implicit_template_parms; 393 394 /* The scope into which an implicit template parameter list has been 395 introduced or an existing template parameter list is being extended with 396 implicit template parameters. In most cases this is the sk_function_parms 397 scope containing the use of a generic type. In the case of an out-of-line 398 member definition using a generic type, it is the sk_class scope. */ 399 cp_binding_level* implicit_template_scope; 400 401 /* True if parsing a result type in a compound requirement. This permits 402 constrained-type-specifiers inside what would normally be a trailing 403 return type. */ 404 bool in_result_type_constraint_p; 405 406 /* True if a constrained-type-specifier is not allowed in this 407 context e.g., because they could never be deduced. */ 408 int prevent_constrained_type_specifiers; 409 410 /* Location of the string-literal token within the current linkage 411 specification, if any, or UNKNOWN_LOCATION otherwise. */ 412 location_t innermost_linkage_specification_location; 413 414 }; 415 416 /* In parser.c */ 417 extern void debug (cp_token &ref); 418 extern void debug (cp_token *ptr); 419 extern void cp_lexer_debug_tokens (vec<cp_token, va_gc> *); 420 extern void debug (vec<cp_token, va_gc> &ref); 421 extern void debug (vec<cp_token, va_gc> *ptr); 422 extern void cp_debug_parser (FILE *, cp_parser *); 423 extern void debug (cp_parser &ref); 424 extern void debug (cp_parser *ptr); 425 extern bool cp_keyword_starts_decl_specifier_p (enum rid keyword); 426 427 #endif /* GCC_CP_PARSER_H */ 428