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cgram.y revision 1.454
      1 %{
      2 /* $NetBSD: cgram.y,v 1.454 2023/07/11 21:13:36 rillig Exp $ */
      3 
      4 /*
      5  * Copyright (c) 1996 Christopher G. Demetriou.  All Rights Reserved.
      6  * Copyright (c) 1994, 1995 Jochen Pohl
      7  * All Rights Reserved.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. All advertising materials mentioning features or use of this software
     18  *    must display the following acknowledgement:
     19  *      This product includes software developed by Jochen Pohl for
     20  *	The NetBSD Project.
     21  * 4. The name of the author may not be used to endorse or promote products
     22  *    derived from this software without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     27  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     28  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     29  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     30  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     31  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     32  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     33  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(__RCSID)
     38 __RCSID("$NetBSD: cgram.y,v 1.454 2023/07/11 21:13:36 rillig Exp $");
     39 #endif
     40 
     41 #include <limits.h>
     42 #include <stdlib.h>
     43 #include <string.h>
     44 
     45 #include "lint1.h"
     46 
     47 extern char *yytext;
     48 
     49 /*
     50  * Contains the level of current declaration, used for symbol table entries.
     51  * 0 is the top-level, > 0 is inside a function body.
     52  */
     53 int	block_level;
     54 
     55 /*
     56  * level for memory allocation. Normally the same as block_level.
     57  * An exception is the declaration of arguments in prototypes. Memory
     58  * for these can't be freed after the declaration, but symbols must
     59  * be removed from the symbol table after the declaration.
     60  */
     61 size_t	mem_block_level;
     62 
     63 /*
     64  * Save the no-warns state and restore it to avoid the problem where
     65  * if (expr) { stmt } / * NOLINT * / stmt;
     66  */
     67 #define LWARN_NOTHING_SAVED (-3)
     68 static int saved_lwarn = LWARN_NOTHING_SAVED;
     69 
     70 static	void	cgram_declare(sym_t *, bool, sbuf_t *);
     71 static	void	read_until_rparen(void);
     72 static	sym_t	*symbolrename(sym_t *, sbuf_t *);
     73 
     74 
     75 /* ARGSUSED */
     76 static void
     77 clear_warning_flags_loc(const char *file, size_t line)
     78 {
     79 	debug_step("%s:%zu: clearing flags", file, line);
     80 	clear_warn_flags();
     81 	saved_lwarn = LWARN_NOTHING_SAVED;
     82 }
     83 
     84 /* ARGSUSED */
     85 static void
     86 save_warning_flags_loc(const char *file, size_t line)
     87 {
     88 	/*
     89 	 * There used to be an assertion that saved_lwarn is
     90 	 * LWARN_NOTHING_SAVED here, but that triggered for the following
     91 	 * code:
     92 	 *
     93 	 * void function(int x) { if (x > 0) if (x > 1) return; }
     94 	 *
     95 	 * It didn't trigger if the inner 'if' was enclosed in braces though.
     96 	 *
     97 	 * TODO: If actually needed, add support for nested suppression of
     98 	 *  warnings.
     99 	 */
    100 	debug_step("%s:%zu: saving flags %d", file, line, lwarn);
    101 	saved_lwarn = lwarn;
    102 }
    103 
    104 /* ARGSUSED */
    105 static void
    106 restore_warning_flags_loc(const char *file, size_t line)
    107 {
    108 	if (saved_lwarn != LWARN_NOTHING_SAVED) {
    109 		lwarn = saved_lwarn;
    110 		debug_step("%s:%zu: restoring flags %d", file, line, lwarn);
    111 		/*
    112 		 * Do not set 'saved_lwarn = LWARN_NOTHING_SAVED' here, to
    113 		 * avoid triggering the assertion in save_warning_flags_loc.
    114 		 */
    115 	} else
    116 		clear_warning_flags_loc(file, line);
    117 }
    118 
    119 #define clear_warning_flags()	clear_warning_flags_loc(__FILE__, __LINE__)
    120 #define save_warning_flags()	save_warning_flags_loc(__FILE__, __LINE__)
    121 #define restore_warning_flags()	restore_warning_flags_loc(__FILE__, __LINE__)
    122 
    123 static bool
    124 is_either(const char *s, const char *a, const char *b)
    125 {
    126 	return strcmp(s, a) == 0 || strcmp(s, b) == 0;
    127 }
    128 
    129 #if YYDEBUG && YYBYACC
    130 #define YYSTYPE_TOSTRING cgram_to_string
    131 #endif
    132 
    133 %}
    134 
    135 %expect 131
    136 
    137 %union {
    138 	val_t	*y_val;
    139 	sbuf_t	*y_name;
    140 	sym_t	*y_sym;
    141 	op_t	y_op;
    142 	scl_t	y_scl;
    143 	tspec_t	y_tspec;
    144 	tqual_t	y_tqual;
    145 	type_t	*y_type;
    146 	tnode_t	*y_tnode;
    147 	range_t	y_range;
    148 	strg_t	*y_string;
    149 	qual_ptr *y_qual_ptr;
    150 	bool	y_seen_statement;
    151 	struct generic_association *y_generic;
    152 	struct array_size y_array_size;
    153 	bool	y_in_system_header;
    154 };
    155 
    156 /* for Bison:
    157 %printer {
    158 	if (is_integer($$->v_tspec))
    159 		fprintf(yyo, "%lld", (unsigned long long)$$->u.integer);
    160 	else
    161 		fprintf(yyo, "%Lg", $$->u.floating);
    162 } <y_val>
    163 %printer { fprintf(yyo, "'%s'", $$ != NULL ? $$->sb_name : "<null>"); } <y_name>
    164 %printer { debug_sym("", $$, ""); } <y_sym>
    165 %printer { fprintf(yyo, "%s", op_name($$)); } <y_op>
    166 %printer { fprintf(yyo, "%s", scl_name($$)); } <y_scl>
    167 %printer { fprintf(yyo, "%s", tspec_name($$)); } <y_tspec>
    168 %printer { fprintf(yyo, "%s", tqual_name($$)); } <y_tqual>
    169 %printer { fprintf(yyo, "%s", type_name($$)); } <y_type>
    170 %printer {
    171 	if ($$ == NULL)
    172 		fprintf(yyo, "<null>");
    173 	else
    174 		fprintf(yyo, "%s '%s'",
    175 		    op_name($$->tn_op), type_name($$->tn_type));
    176 } <y_tnode>
    177 %printer { fprintf(yyo, "%zu to %zu", $$.lo, $$.hi); } <y_range>
    178 %printer { fprintf(yyo, "length %zu", $$->st_len); } <y_string>
    179 %printer {
    180 	fprintf(yyo, "%s%s%s",
    181 	    $$->p_const ? "const " : "",
    182 	    $$->p_volatile ? "volatile " : "",
    183 	    $$->p_pointer ? "*" : "");
    184 } <y_qual_ptr>
    185 %printer { fprintf(yyo, "%s", $$ ? "yes" : "no"); } <y_seen_statement>
    186 %printer { fprintf(yyo, "%s", type_name($$->ga_arg)); } <y_generic>
    187 %printer { fprintf(yyo, "%d", $$.dim); } <y_array_size>
    188 %printer { fprintf(yyo, "%s", $$ ? "yes" : "no"); } <y_in_system_header>
    189 */
    190 
    191 %token			T_LBRACE T_RBRACE T_LBRACK T_RBRACK T_LPAREN T_RPAREN
    192 %token			T_POINT T_ARROW
    193 %token			T_COMPLEMENT T_LOGNOT
    194 %token	<y_op>		T_INCDEC
    195 %token			T_SIZEOF
    196 %token			T_BUILTIN_OFFSETOF
    197 %token			T_TYPEOF
    198 %token			T_EXTENSION
    199 %token			T_ALIGNAS
    200 %token			T_ALIGNOF
    201 %token			T_ASTERISK
    202 %token	<y_op>		T_MULTIPLICATIVE
    203 %token	<y_op>		T_ADDITIVE
    204 %token	<y_op>		T_SHIFT
    205 %token	<y_op>		T_RELATIONAL
    206 %token	<y_op>		T_EQUALITY
    207 %token			T_AMPER
    208 %token			T_BITXOR
    209 %token			T_BITOR
    210 %token			T_LOGAND
    211 %token			T_LOGOR
    212 %token			T_QUEST
    213 %token			T_COLON
    214 %token			T_ASSIGN
    215 %token	<y_op>		T_OPASSIGN
    216 %token			T_COMMA
    217 %token			T_SEMI
    218 %token			T_ELLIPSIS
    219 %token			T_REAL
    220 %token			T_IMAG
    221 %token			T_GENERIC
    222 %token			T_NORETURN
    223 
    224 /* storage classes (extern, static, auto, register and typedef) */
    225 %token	<y_scl>		T_SCLASS
    226 
    227 /*
    228  * predefined type keywords (char, int, short, long, unsigned, signed,
    229  * float, double, void); see T_TYPENAME for types from typedef
    230  */
    231 %token	<y_tspec>	T_TYPE
    232 
    233 /* qualifiers (const, volatile, restrict, _Thread_local) */
    234 %token	<y_tqual>	T_QUAL
    235 %token	<y_tqual>	T_ATOMIC
    236 
    237 /* struct or union */
    238 %token	<y_tspec>	T_STRUCT_OR_UNION
    239 
    240 /* remaining keywords */
    241 %token			T_ASM
    242 %token			T_BREAK
    243 %token			T_CASE
    244 %token			T_CONTINUE
    245 %token			T_DEFAULT
    246 %token			T_DO
    247 %token			T_ELSE
    248 %token			T_ENUM
    249 %token			T_FOR
    250 %token			T_GOTO
    251 %token			T_IF
    252 %token			T_PACKED
    253 %token			T_RETURN
    254 %token			T_SWITCH
    255 %token			T_SYMBOLRENAME
    256 %token			T_WHILE
    257 %token			T_STATIC_ASSERT
    258 
    259 %token			T_ATTRIBUTE
    260 
    261 %left	T_THEN
    262 %left	T_ELSE
    263 %right	T_QUEST T_COLON
    264 %left	T_LOGOR
    265 %left	T_LOGAND
    266 %left	T_BITOR
    267 %left	T_BITXOR
    268 %left	T_AMPER
    269 %left	T_EQUALITY
    270 %left	T_RELATIONAL
    271 %left	T_SHIFT
    272 %left	T_ADDITIVE
    273 %left	T_ASTERISK T_MULTIPLICATIVE
    274 
    275 %token	<y_name>	T_NAME
    276 %token	<y_name>	T_TYPENAME
    277 %token	<y_val>		T_CON
    278 %token	<y_string>	T_STRING
    279 
    280 /* No type for program. */
    281 %type	<y_sym>		identifier_sym
    282 %type	<y_name>	identifier
    283 %type	<y_string>	string
    284 %type	<y_tnode>	primary_expression
    285 %type	<y_tnode>	generic_selection
    286 %type	<y_generic>	generic_assoc_list
    287 %type	<y_generic>	generic_association
    288 %type	<y_tnode>	postfix_expression
    289 /* No type for comma_opt. */
    290 %type	<y_tnode>	gcc_statement_expr_list
    291 %type	<y_tnode>	gcc_statement_expr_item
    292 %type	<y_op>		point_or_arrow
    293 %type	<y_tnode>	argument_expression_list
    294 %type	<y_tnode>	unary_expression
    295 %type	<y_tnode>	cast_expression
    296 %type	<y_tnode>	expression_opt
    297 %type	<y_tnode>	conditional_expression
    298 %type	<y_tnode>	assignment_expression
    299 %type	<y_tnode>	expression
    300 %type	<y_tnode>	constant_expression
    301 /* No type for declaration_or_error. */
    302 /* No type for declaration. */
    303 /* No type for begin_type_declaration_specifiers. */
    304 /* No type for begin_type_declmods. */
    305 /* No type for begin_type_specifier_qualifier_list. */
    306 /* No type for begin_type_specifier_qualifier_list_postfix. */
    307 %type	<y_type>	begin_type_typespec
    308 /* No type for begin_type_qualifier_list. */
    309 /* No type for declmod. */
    310 /* No type for type_attribute_list_opt. */
    311 /* No type for type_attribute_list. */
    312 /* No type for type_attribute_opt. */
    313 /* No type for type_attribute. */
    314 /* No type for begin_type. */
    315 /* No type for end_type. */
    316 %type	<y_type>	type_specifier
    317 %type	<y_type>	notype_type_specifier
    318 %type	<y_type>	atomic_type_specifier
    319 %type	<y_type>	struct_or_union_specifier
    320 %type	<y_tspec>	struct_or_union
    321 %type	<y_sym>		braced_member_declaration_list
    322 /* No type for member_declaration_lbrace. */
    323 %type	<y_sym>		member_declaration_list_with_rbrace
    324 %type	<y_sym>		member_declaration_list
    325 %type	<y_sym>		member_declaration
    326 %type	<y_sym>		notype_member_declarators
    327 %type	<y_sym>		type_member_declarators
    328 %type	<y_sym>		notype_member_declarator
    329 %type	<y_sym>		type_member_declarator
    330 %type	<y_type>	enum_specifier
    331 /* No type for enum. */
    332 %type	<y_sym>		enum_declaration
    333 /* No type for enum_decl_lbrace. */
    334 %type	<y_sym>		enums_with_opt_comma
    335 %type	<y_sym>		enumerator_list
    336 %type	<y_sym>		enumerator
    337 %type	<y_tqual>	type_qualifier
    338 /* No type for atomic. */
    339 %type	<y_qual_ptr>	pointer
    340 %type	<y_qual_ptr>	asterisk
    341 %type	<y_qual_ptr>	type_qualifier_list_opt
    342 %type	<y_qual_ptr>	type_qualifier_list
    343 %type	<y_qual_ptr>	type_qualifier_list_elem
    344 /* No type for notype_init_declarators. */
    345 /* No type for type_init_declarators. */
    346 /* No type for notype_init_declarator. */
    347 /* No type for type_init_declarator. */
    348 %type	<y_sym>		notype_declarator
    349 %type	<y_sym>		type_declarator
    350 %type	<y_sym>		notype_direct_declarator
    351 %type	<y_sym>		type_direct_declarator
    352 %type	<y_sym>		type_param_declarator
    353 %type	<y_sym>		notype_param_declarator
    354 %type	<y_sym>		direct_param_declarator
    355 %type	<y_sym>		direct_notype_param_declarator
    356 %type	<y_sym>		param_list
    357 /* No type for id_list_lparen. */
    358 /* No type for abstract_decl_lparen. */
    359 %type	<y_array_size>	array_size_opt
    360 %type	<y_tnode>	array_size
    361 %type	<y_sym>		identifier_list
    362 %type	<y_type>	type_name
    363 %type	<y_sym>		abstract_declaration
    364 %type	<y_sym>		abstract_declarator
    365 %type	<y_sym>		direct_abstract_declarator
    366 %type	<y_sym>		abstract_decl_param_list
    367 /* No type for abstract_decl_lparen. */
    368 %type	<y_sym>		vararg_parameter_type_list
    369 %type	<y_sym>		parameter_type_list
    370 %type	<y_sym>		parameter_declaration
    371 /* No type for braced_initializer. */
    372 /* No type for initializer. */
    373 /* No type for initializer_list. */
    374 /* No type for initializer_list_item. */
    375 /* No type for designation. */
    376 /* No type for begin_designation. */
    377 /* No type for designator_list. */
    378 /* No type for designator. */
    379 /* No type for static_assert_declaration. */
    380 %type	<y_range>	range
    381 /* No type for init_lbrace. */
    382 /* No type for init_rbrace. */
    383 %type	<y_name>	asm_or_symbolrename_opt
    384 /* No type for statement. */
    385 /* No type for non_expr_statement. */
    386 /* No type for labeled_statement. */
    387 /* No type for label. */
    388 /* No type for compound_statement. */
    389 /* No type for compound_statement_lbrace. */
    390 /* No type for compound_statement_rbrace. */
    391 %type	<y_seen_statement> block_item_list
    392 %type	<y_seen_statement> block_item
    393 /* No type for expression_statement. */
    394 /* No type for selection_statement. */
    395 /* No type for if_without_else. */
    396 /* No type for if_expr. */
    397 /* No type for switch_expr. */
    398 /* No type for iteration_statement. */
    399 /* No type for while_expr. */
    400 /* No type for do_statement. */
    401 /* No type for do. */
    402 %type	<y_tnode>	do_while_expr
    403 /* No type for for_start. */
    404 /* No type for for_exprs. */
    405 /* No type for jump_statement. */
    406 /* No type for goto. */
    407 /* No type for asm_statement. */
    408 /* No type for read_until_rparen. */
    409 /* No type for translation_unit. */
    410 /* No type for external_declaration. */
    411 /* No type for top_level_declaration. */
    412 /* No type for function_definition. */
    413 %type	<y_sym>		func_declarator
    414 /* No type for arg_declaration_list_opt. */
    415 /* No type for arg_declaration_list. */
    416 /* No type for arg_declaration. */
    417 /* No type for gcc_attribute_specifier_list_opt. */
    418 /* No type for gcc_attribute_specifier_list. */
    419 /* No type for gcc_attribute_specifier. */
    420 /* No type for gcc_attribute_list. */
    421 /* No type for gcc_attribute. */
    422 /* No type for gcc_attribute_parameters. */
    423 %type	<y_in_system_header> sys
    424 
    425 %%
    426 
    427 program:
    428 	  /* empty */ {
    429 		/* TODO: Make this an error in C99 mode as well. */
    430 		if (!allow_trad && !allow_c99) {
    431 			/* empty translation unit */
    432 			error(272);
    433 		} else if (allow_c90) {
    434 			/* empty translation unit */
    435 			warning(272);
    436 		}
    437 	  }
    438 	| translation_unit
    439 	;
    440 
    441 identifier_sym:			/* helper for struct/union/enum */
    442 	  identifier {
    443 		$$ = getsym($1);
    444 	  }
    445 	;
    446 
    447 /* K&R ???, C90 ???, C99 6.4.2.1, C11 ??? */
    448 identifier:
    449 	  T_NAME {
    450 		debug_step("cgram: name '%s'", $1->sb_name);
    451 		$$ = $1;
    452 	  }
    453 	| T_TYPENAME {
    454 		debug_step("cgram: typename '%s'", $1->sb_name);
    455 		$$ = $1;
    456 	  }
    457 	;
    458 
    459 /* see C99 6.4.5, string literals are joined by 5.1.1.2 */
    460 string:
    461 	  T_STRING
    462 	| string T_STRING {
    463 		if (!allow_c90) {
    464 			/* concatenated strings are illegal in traditional C */
    465 			warning(219);
    466 		}
    467 		$$ = cat_strings($1, $2);
    468 	  }
    469 	;
    470 
    471 /* K&R 7.1, C90 ???, C99 6.5.1, C11 6.5.1 */
    472 primary_expression:
    473 	  T_NAME {
    474 		bool sys_name, sys_next;
    475 		sys_name = in_system_header;
    476 		if (yychar < 0)
    477 			yychar = yylex();
    478 		sys_next = in_system_header;
    479 		in_system_header = sys_name;
    480 		$$ = build_name(getsym($1), yychar == T_LPAREN);
    481 		in_system_header = sys_next;
    482 	  }
    483 	| T_CON {
    484 		$$ = build_constant(gettyp($1->v_tspec), $1);
    485 	  }
    486 	| string {
    487 		$$ = build_string($1);
    488 	  }
    489 	| T_LPAREN expression T_RPAREN {
    490 		if ($2 != NULL)
    491 			$2->tn_parenthesized = true;
    492 		$$ = $2;
    493 	  }
    494 	| generic_selection
    495 	/* GCC primary-expression, see c_parser_postfix_expression */
    496 	/* TODO: C99 7.17p3 allows not only an identifier but a designator. */
    497 	| T_BUILTIN_OFFSETOF T_LPAREN type_name T_COMMA identifier T_RPAREN {
    498 		set_symtyp(FMEMBER);
    499 		$$ = build_offsetof($3, getsym($5));
    500 	  }
    501 	;
    502 
    503 /* K&R ---, C90 ---, C99 ---, C11 6.5.1.1 */
    504 generic_selection:
    505 	  T_GENERIC T_LPAREN assignment_expression T_COMMA
    506 	    generic_assoc_list T_RPAREN {
    507 		/* generic selection requires C11 or later */
    508 		c11ism(345);
    509 		$$ = build_generic_selection($3, $5);
    510 	  }
    511 	;
    512 
    513 /* K&R ---, C90 ---, C99 ---, C11 6.5.1.1 */
    514 generic_assoc_list:
    515 	  generic_association
    516 	| generic_assoc_list T_COMMA generic_association {
    517 		$3->ga_prev = $1;
    518 		$$ = $3;
    519 	  }
    520 	;
    521 
    522 /* K&R ---, C90 ---, C99 ---, C11 6.5.1.1 */
    523 generic_association:
    524 	  type_name T_COLON assignment_expression {
    525 		$$ = block_zero_alloc(sizeof(*$$));
    526 		$$->ga_arg = $1;
    527 		$$->ga_result = $3;
    528 	  }
    529 	| T_DEFAULT T_COLON assignment_expression {
    530 		$$ = block_zero_alloc(sizeof(*$$));
    531 		$$->ga_arg = NULL;
    532 		$$->ga_result = $3;
    533 	  }
    534 	;
    535 
    536 /* K&R 7.1, C90 ???, C99 6.5.2, C11 6.5.2, C23 6.5.2 */
    537 postfix_expression:
    538 	  primary_expression
    539 	| postfix_expression T_LBRACK sys expression T_RBRACK {
    540 		$$ = build_unary(INDIR, $3, build_binary($1, PLUS, $3, $4));
    541 	  }
    542 	| postfix_expression T_LPAREN sys T_RPAREN {
    543 		$$ = build_function_call($1, $3, NULL);
    544 	  }
    545 	| postfix_expression T_LPAREN sys argument_expression_list T_RPAREN {
    546 		$$ = build_function_call($1, $3, $4);
    547 	  }
    548 	| postfix_expression point_or_arrow sys T_NAME {
    549 		$$ = build_member_access($1, $2, $3, $4);
    550 	  }
    551 	| postfix_expression T_INCDEC sys {
    552 		$$ = build_unary($2 == INC ? INCAFT : DECAFT, $3, $1);
    553 	  }
    554 	| T_LPAREN type_name T_RPAREN {	/* C99 6.5.2.5 "Compound literals" */
    555 		sym_t *tmp = mktempsym($2);
    556 		begin_initialization(tmp);
    557 		cgram_declare(tmp, true, NULL);
    558 	  } braced_initializer {
    559 		if (!allow_c99)
    560 			 /* compound literals are a C99/GCC extension */
    561 			 gnuism(319);
    562 		$$ = build_name(current_initsym(), false);
    563 		end_initialization();
    564 	  }
    565 	| T_LPAREN compound_statement_lbrace {
    566 		begin_statement_expr();
    567 	  } gcc_statement_expr_list {
    568 		do_statement_expr($4);
    569 	  } compound_statement_rbrace T_RPAREN {
    570 		$$ = end_statement_expr();
    571 	  }
    572 	;
    573 
    574 comma_opt:			/* helper for 'postfix_expression' */
    575 	  /* empty */
    576 	| T_COMMA
    577 	;
    578 
    579 /*
    580  * The inner part of a GCC statement-expression of the form ({ ... }).
    581  *
    582  * https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html
    583  */
    584 gcc_statement_expr_list:
    585 	  gcc_statement_expr_item
    586 	| gcc_statement_expr_list gcc_statement_expr_item {
    587 		$$ = $2;
    588 	  }
    589 	;
    590 
    591 gcc_statement_expr_item:
    592 	  declaration_or_error {
    593 		clear_warning_flags();
    594 		$$ = NULL;
    595 	  }
    596 	| non_expr_statement {
    597 		$$ = expr_alloc_tnode();
    598 		$$->tn_type = gettyp(VOID);
    599 	  }
    600 	| T_SEMI {
    601 		$$ = expr_alloc_tnode();
    602 		$$->tn_type = gettyp(VOID);
    603 	  }
    604 	| expression T_SEMI {
    605 		if ($1 == NULL) {	/* in case of syntax errors */
    606 			$$ = expr_alloc_tnode();
    607 			$$->tn_type = gettyp(VOID);
    608 		} else {
    609 			/* XXX: do that only on the last name */
    610 			if ($1->tn_op == NAME)
    611 				$1->tn_sym->s_used = true;
    612 			expr($1, false, false, false, false);
    613 			seen_fallthrough = false;
    614 			$$ = $1;
    615 		}
    616 	  }
    617 	;
    618 
    619 point_or_arrow:			/* helper for 'postfix_expression' */
    620 	  T_POINT {
    621 		set_symtyp(FMEMBER);
    622 		$$ = POINT;
    623 	  }
    624 	| T_ARROW {
    625 		set_symtyp(FMEMBER);
    626 		$$ = ARROW;
    627 	  }
    628 	;
    629 
    630 /* K&R 7.1, C90 ???, C99 6.5.2, C11 6.5.2 */
    631 argument_expression_list:
    632 	  assignment_expression {
    633 		$$ = build_function_argument(NULL, $1);
    634 	  }
    635 	| argument_expression_list T_COMMA assignment_expression {
    636 		$$ = build_function_argument($1, $3);
    637 	  }
    638 	;
    639 
    640 /* K&R 7.2, C90 ???, C99 6.5.3, C11 6.5.3 */
    641 unary_expression:
    642 	  postfix_expression
    643 	| T_INCDEC sys unary_expression {
    644 		$$ = build_unary($1 == INC ? INCBEF : DECBEF, $2, $3);
    645 	  }
    646 	| T_AMPER sys cast_expression {
    647 		$$ = build_unary(ADDR, $2, $3);
    648 	  }
    649 	| T_ASTERISK sys cast_expression {
    650 		$$ = build_unary(INDIR, $2, $3);
    651 	  }
    652 	| T_ADDITIVE sys cast_expression {
    653 		if (!allow_c90 && $1 == PLUS) {
    654 			/* unary '+' is illegal in traditional C */
    655 			warning(100);
    656 		}
    657 		$$ = build_unary($1 == PLUS ? UPLUS : UMINUS, $2, $3);
    658 	  }
    659 	| T_COMPLEMENT sys cast_expression {
    660 		$$ = build_unary(COMPL, $2, $3);
    661 	  }
    662 	| T_LOGNOT sys cast_expression {
    663 		$$ = build_unary(NOT, $2, $3);
    664 	  }
    665 	| T_REAL sys cast_expression {	/* GCC c_parser_unary_expression */
    666 		$$ = build_unary(REAL, $2, $3);
    667 	  }
    668 	| T_IMAG sys cast_expression {	/* GCC c_parser_unary_expression */
    669 		$$ = build_unary(IMAG, $2, $3);
    670 	  }
    671 	| T_EXTENSION cast_expression {	/* GCC c_parser_unary_expression */
    672 		$$ = $2;
    673 	  }
    674 	| T_SIZEOF unary_expression {
    675 		$$ = $2 == NULL ? NULL : build_sizeof($2->tn_type);
    676 		if ($$ != NULL)
    677 			check_expr_misc($2,
    678 			    false, false, false, false, false, true);
    679 	  }
    680 	| T_SIZEOF T_LPAREN type_name T_RPAREN {
    681 		$$ = build_sizeof($3);
    682 	  }
    683 	| T_ALIGNOF unary_expression {
    684 		/* non type argument to alignof is a GCC extension */
    685 		gnuism(349);
    686 		lint_assert($2 != NULL);
    687 		$$ = build_alignof($2->tn_type);
    688 	  }
    689 	/* K&R ---, C90 ---, C99 ---, C11 6.5.3 */
    690 	| T_ALIGNOF T_LPAREN type_name T_RPAREN {
    691 		/* TODO: c11ism */
    692 		$$ = build_alignof($3);
    693 	  }
    694 	;
    695 
    696 /* The rule 'unary_operator' is inlined into unary_expression. */
    697 
    698 /* K&R 7.2, C90 ???, C99 6.5.4, C11 6.5.4 */
    699 cast_expression:
    700 	  unary_expression
    701 	| T_LPAREN type_name T_RPAREN cast_expression {
    702 		$$ = cast($4, $2);
    703 	  }
    704 	;
    705 
    706 expression_opt:
    707 	  /* empty */ {
    708 		$$ = NULL;
    709 	  }
    710 	| expression
    711 	;
    712 
    713 /* 'conditional_expression' also implements 'multiplicative_expression'. */
    714 /* 'conditional_expression' also implements 'additive_expression'. */
    715 /* 'conditional_expression' also implements 'shift_expression'. */
    716 /* 'conditional_expression' also implements 'relational_expression'. */
    717 /* 'conditional_expression' also implements 'equality_expression'. */
    718 /* 'conditional_expression' also implements 'AND_expression'. */
    719 /* 'conditional_expression' also implements 'exclusive_OR_expression'. */
    720 /* 'conditional_expression' also implements 'inclusive_OR_expression'. */
    721 /* 'conditional_expression' also implements 'logical_AND_expression'. */
    722 /* 'conditional_expression' also implements 'logical_OR_expression'. */
    723 /* K&R ???, C90 ???, C99 6.5.5 to 6.5.15, C11 6.5.5 to 6.5.15 */
    724 conditional_expression:
    725 	  cast_expression
    726 	| conditional_expression T_ASTERISK sys conditional_expression {
    727 		$$ = build_binary($1, MULT, $3, $4);
    728 	  }
    729 	| conditional_expression T_MULTIPLICATIVE sys conditional_expression {
    730 		$$ = build_binary($1, $2, $3, $4);
    731 	  }
    732 	| conditional_expression T_ADDITIVE sys conditional_expression {
    733 		$$ = build_binary($1, $2, $3, $4);
    734 	  }
    735 	| conditional_expression T_SHIFT sys conditional_expression {
    736 		$$ = build_binary($1, $2, $3, $4);
    737 	  }
    738 	| conditional_expression T_RELATIONAL sys conditional_expression {
    739 		$$ = build_binary($1, $2, $3, $4);
    740 	  }
    741 	| conditional_expression T_EQUALITY sys conditional_expression {
    742 		$$ = build_binary($1, $2, $3, $4);
    743 	  }
    744 	| conditional_expression T_AMPER sys conditional_expression {
    745 		$$ = build_binary($1, BITAND, $3, $4);
    746 	  }
    747 	| conditional_expression T_BITXOR sys conditional_expression {
    748 		$$ = build_binary($1, BITXOR, $3, $4);
    749 	  }
    750 	| conditional_expression T_BITOR sys conditional_expression {
    751 		$$ = build_binary($1, BITOR, $3, $4);
    752 	  }
    753 	| conditional_expression T_LOGAND sys conditional_expression {
    754 		$$ = build_binary($1, LOGAND, $3, $4);
    755 	  }
    756 	| conditional_expression T_LOGOR sys conditional_expression {
    757 		$$ = build_binary($1, LOGOR, $3, $4);
    758 	  }
    759 	| conditional_expression T_QUEST sys
    760 	    expression T_COLON sys conditional_expression {
    761 		$$ = build_binary($1, QUEST, $3,
    762 		    build_binary($4, COLON, $6, $7));
    763 	  }
    764 	;
    765 
    766 /* K&R ???, C90 ???, C99 6.5.16, C11 6.5.16 */
    767 assignment_expression:
    768 	  conditional_expression
    769 	| unary_expression T_ASSIGN sys assignment_expression {
    770 		$$ = build_binary($1, ASSIGN, $3, $4);
    771 	  }
    772 	| unary_expression T_OPASSIGN sys assignment_expression {
    773 		$$ = build_binary($1, $2, $3, $4);
    774 	  }
    775 	;
    776 
    777 /* K&R ???, C90 ???, C99 6.5.17, C11 6.5.17 */
    778 expression:
    779 	  assignment_expression
    780 	| expression T_COMMA sys assignment_expression {
    781 		$$ = build_binary($1, COMMA, $3, $4);
    782 	  }
    783 	;
    784 
    785 /* K&R ???, C90 ???, C99 6.6, C11 ???, C23 6.6 */
    786 constant_expression:
    787 	  conditional_expression
    788 	;
    789 
    790 declaration_or_error:
    791 	  declaration
    792 	| error T_SEMI
    793 	;
    794 
    795 /* K&R ???, C90 ???, C99 6.7, C11 ???, C23 6.7 */
    796 declaration:
    797 	  begin_type_declmods end_type T_SEMI {
    798 		if (dcs->d_scl == TYPEDEF) {
    799 			/* typedef declares no type name */
    800 			warning(72);
    801 		} else {
    802 			/* empty declaration */
    803 			warning(2);
    804 		}
    805 	  }
    806 	| begin_type_declmods end_type notype_init_declarators T_SEMI {
    807 		if (dcs->d_scl == TYPEDEF) {
    808 			/* syntax error '%s' */
    809 			error(249, "missing base type for typedef");
    810 		} else {
    811 			/* old-style declaration; add 'int' */
    812 			error(1);
    813 		}
    814 	  }
    815 	| begin_type_declaration_specifiers end_type T_SEMI {
    816 		if (dcs->d_scl == TYPEDEF) {
    817 			/* typedef declares no type name */
    818 			warning(72);
    819 		} else if (!dcs->d_nonempty_decl) {
    820 			/* empty declaration */
    821 			warning(2);
    822 		}
    823 	  }
    824 	| begin_type_declaration_specifiers end_type
    825 	    type_init_declarators T_SEMI
    826 	| static_assert_declaration
    827 	;
    828 
    829 begin_type_declaration_specifiers:	/* see C99 6.7 */
    830 	  begin_type_typespec {
    831 		dcs_add_type($1);
    832 	  }
    833 	| begin_type_declmods type_specifier {
    834 		dcs_add_type($2);
    835 	  }
    836 	| type_attribute begin_type_declaration_specifiers
    837 	| begin_type_declaration_specifiers declmod
    838 	| begin_type_declaration_specifiers notype_type_specifier {
    839 		dcs_add_type($2);
    840 	  }
    841 	;
    842 
    843 begin_type_declmods:		/* see C99 6.7 */
    844 	  begin_type type_qualifier {
    845 		dcs_add_qualifier($2);
    846 	  }
    847 	| begin_type T_SCLASS {
    848 		dcs_add_storage_class($2);
    849 	  }
    850 	| begin_type_declmods declmod
    851 	;
    852 
    853 begin_type_specifier_qualifier_list:	/* see C11 6.7.2.1 */
    854 	  begin_type_specifier_qualifier_list_postfix
    855 	| type_attribute_list begin_type_specifier_qualifier_list_postfix
    856 	;
    857 
    858 begin_type_specifier_qualifier_list_postfix:
    859 	  begin_type_typespec {
    860 		dcs_add_type($1);
    861 	  }
    862 	| begin_type_qualifier_list type_specifier {
    863 		dcs_add_type($2);
    864 	  }
    865 	| begin_type_specifier_qualifier_list_postfix type_qualifier {
    866 		dcs_add_qualifier($2);
    867 	  }
    868 	| begin_type_specifier_qualifier_list_postfix notype_type_specifier {
    869 		dcs_add_type($2);
    870 	  }
    871 	| begin_type_specifier_qualifier_list_postfix type_attribute
    872 	;
    873 
    874 begin_type_typespec:
    875 	  begin_type notype_type_specifier {
    876 		$$ = $2;
    877 	  }
    878 	| begin_type T_TYPENAME {
    879 		$$ = getsym($2)->s_type;
    880 	  }
    881 	;
    882 
    883 begin_type_qualifier_list:
    884 	  begin_type type_qualifier {
    885 		dcs_add_qualifier($2);
    886 	  }
    887 	| begin_type_qualifier_list type_qualifier {
    888 		dcs_add_qualifier($2);
    889 	  }
    890 	;
    891 
    892 declmod:
    893 	  type_qualifier {
    894 		dcs_add_qualifier($1);
    895 	  }
    896 	| T_SCLASS {
    897 		dcs_add_storage_class($1);
    898 	  }
    899 	| type_attribute_list
    900 	;
    901 
    902 type_attribute_list_opt:
    903 	  /* empty */
    904 	| type_attribute_list
    905 	;
    906 
    907 type_attribute_list:
    908 	  type_attribute
    909 	| type_attribute_list type_attribute
    910 	;
    911 
    912 type_attribute_opt:
    913 	  /* empty */
    914 	| type_attribute
    915 	;
    916 
    917 type_attribute:			/* See C11 6.7 declaration-specifiers */
    918 	  gcc_attribute_specifier
    919 	| T_ALIGNAS T_LPAREN type_specifier T_RPAREN	/* C11 6.7.5 */
    920 	| T_ALIGNAS T_LPAREN constant_expression T_RPAREN	/* C11 6.7.5 */
    921 	| T_PACKED {
    922 		dcs_add_packed();
    923 	  }
    924 	| T_NORETURN
    925 	;
    926 
    927 begin_type:
    928 	  /* empty */ {
    929 		dcs_begin_type();
    930 	  }
    931 	;
    932 
    933 end_type:
    934 	  /* empty */ {
    935 		dcs_end_type();
    936 	  }
    937 	;
    938 
    939 type_specifier:			/* C99 6.7.2 */
    940 	  notype_type_specifier
    941 	| T_TYPENAME {
    942 		$$ = getsym($1)->s_type;
    943 	  }
    944 	;
    945 
    946 notype_type_specifier:		/* see C99 6.7.2 */
    947 	  T_TYPE {
    948 		$$ = gettyp($1);
    949 	  }
    950 	| T_TYPEOF T_LPAREN expression T_RPAREN {	/* GCC extension */
    951 		$$ = $3 != NULL ? block_dup_type($3->tn_type) : gettyp(INT);
    952 		$$->t_typeof = true;
    953 	  }
    954 	| atomic_type_specifier
    955 	| struct_or_union_specifier {
    956 		end_declaration_level();
    957 		$$ = $1;
    958 	  }
    959 	| enum_specifier {
    960 		end_declaration_level();
    961 		$$ = $1;
    962 	  }
    963 	;
    964 
    965 /* K&R ---, C90 ---, C99 ---, C11 6.7.2.4 */
    966 atomic_type_specifier:
    967 	  atomic T_LPAREN type_name T_RPAREN {
    968 		$$ = $3;
    969 	  }
    970 	;
    971 
    972 /* K&R ---, C90 ---, C99 6.7.2.1, C11 ???, C23 6.7.2.1 */
    973 struct_or_union_specifier:
    974 	  struct_or_union identifier_sym {
    975 		/*
    976 		 * STDC requires that "struct a;" always introduces
    977 		 * a new tag if "a" is not declared at current level
    978 		 *
    979 		 * yychar is valid because otherwise the parser would not
    980 		 * have been able to decide if it must shift or reduce
    981 		 */
    982 		$$ = make_tag_type($2, $1, false, yychar == T_SEMI);
    983 	  }
    984 	| struct_or_union identifier_sym {
    985 		dcs->d_tag_type = make_tag_type($2, $1, true, false);
    986 	  } braced_member_declaration_list {
    987 		$$ = complete_struct_or_union($4);
    988 	  }
    989 	| struct_or_union {
    990 		dcs->d_tag_type = make_tag_type(NULL, $1, true, false);
    991 	  } braced_member_declaration_list {
    992 		$$ = complete_struct_or_union($3);
    993 	  }
    994 	| struct_or_union error {
    995 		set_symtyp(FVFT);
    996 		$$ = gettyp(INT);
    997 	  }
    998 	;
    999 
   1000 /* K&R ---, C90 ---, C99 6.7.2.1, C11 ???, C23 6.7.2.1 */
   1001 struct_or_union:
   1002 	  T_STRUCT_OR_UNION {
   1003 		set_symtyp(FTAG);
   1004 		begin_declaration_level($1 == STRUCT ? DLK_STRUCT : DLK_UNION);
   1005 		dcs->d_sou_size_in_bits = 0;
   1006 		dcs->d_sou_align_in_bits = CHAR_SIZE;
   1007 		$$ = $1;
   1008 	  }
   1009 	| struct_or_union type_attribute
   1010 	;
   1011 
   1012 braced_member_declaration_list:	/* see C99 6.7.2.1 */
   1013 	  member_declaration_lbrace member_declaration_list_with_rbrace {
   1014 		$$ = $2;
   1015 	  }
   1016 	;
   1017 
   1018 member_declaration_lbrace:	/* see C99 6.7.2.1 */
   1019 	  T_LBRACE {
   1020 		set_symtyp(FVFT);
   1021 	  }
   1022 	;
   1023 
   1024 member_declaration_list_with_rbrace:	/* see C99 6.7.2.1 */
   1025 	  member_declaration_list T_RBRACE
   1026 	| T_RBRACE {
   1027 		/* XXX: This is not allowed by any C standard. */
   1028 		$$ = NULL;
   1029 	  }
   1030 	;
   1031 
   1032 /* K&R ???, C90 ???, C99 6.7.2.1, C11 6.7.2.1, C23 6.7.2.1 */
   1033 /* Was named struct_declaration_list until C11. */
   1034 member_declaration_list:
   1035 	  member_declaration
   1036 	| member_declaration_list member_declaration {
   1037 		$$ = concat_symbols($1, $2);
   1038 	  }
   1039 	;
   1040 
   1041 /* Was named struct_declaration until C11. */
   1042 /* K&R ???, C90 ???, C99 6.7.2.1, C11 6.7.2.1, C23 6.7.2.1 */
   1043 member_declaration:
   1044 	  begin_type_qualifier_list end_type {
   1045 		/* ^^ There is no check for the missing type-specifier. */
   1046 		/* too late, i know, but getsym() compensates it */
   1047 		set_symtyp(FMEMBER);
   1048 	  } notype_member_declarators type_attribute_opt T_SEMI {
   1049 		set_symtyp(FVFT);
   1050 		$$ = $4;
   1051 	  }
   1052 	| begin_type_specifier_qualifier_list end_type {
   1053 		set_symtyp(FMEMBER);
   1054 	  } type_member_declarators type_attribute_opt T_SEMI {
   1055 		set_symtyp(FVFT);
   1056 		$$ = $4;
   1057 	  }
   1058 	| begin_type_qualifier_list end_type type_attribute_opt T_SEMI {
   1059 		/* syntax error '%s' */
   1060 		error(249, "member without type");
   1061 		$$ = NULL;
   1062 	  }
   1063 	| begin_type_specifier_qualifier_list end_type type_attribute_opt
   1064 	    T_SEMI {
   1065 		set_symtyp(FVFT);
   1066 		if (!allow_c11 && !allow_gcc)
   1067 			/* anonymous struct/union members is a C11 feature */
   1068 			warning(49);
   1069 		if (is_struct_or_union(dcs->d_type->t_tspec))
   1070 			$$ = declare_unnamed_member();
   1071 		else {
   1072 			/* syntax error '%s' */
   1073 			error(249, "unnamed member");
   1074 			$$ = NULL;
   1075 		}
   1076 	  }
   1077 	| static_assert_declaration {
   1078 		$$ = NULL;
   1079 	  }
   1080 	| error T_SEMI {
   1081 		set_symtyp(FVFT);
   1082 		$$ = NULL;
   1083 	  }
   1084 	;
   1085 
   1086 /* Was named struct_declarators until C11. */
   1087 notype_member_declarators:
   1088 	  notype_member_declarator {
   1089 		$$ = declare_member($1);
   1090 	  }
   1091 	| notype_member_declarators {
   1092 		set_symtyp(FMEMBER);
   1093 	  } T_COMMA type_member_declarator {
   1094 		$$ = concat_symbols($1, declare_member($4));
   1095 	  }
   1096 	;
   1097 
   1098 /* Was named struct_declarators until C11. */
   1099 type_member_declarators:
   1100 	  type_member_declarator {
   1101 		$$ = declare_member($1);
   1102 	  }
   1103 	| type_member_declarators {
   1104 		set_symtyp(FMEMBER);
   1105 	  } T_COMMA type_member_declarator {
   1106 		$$ = concat_symbols($1, declare_member($4));
   1107 	  }
   1108 	;
   1109 
   1110 /* Was named struct_declarator until C11. */
   1111 notype_member_declarator:
   1112 	  notype_declarator
   1113 	/* C99 6.7.2.1 */
   1114 	| notype_declarator T_COLON constant_expression {
   1115 		$$ = set_bit_field_width($1, to_int_constant($3, true));
   1116 	  }
   1117 	/* C99 6.7.2.1 */
   1118 	| {
   1119 		set_symtyp(FVFT);
   1120 	  } T_COLON constant_expression {
   1121 		$$ = set_bit_field_width(NULL, to_int_constant($3, true));
   1122 	  }
   1123 	;
   1124 
   1125 /* Was named struct_declarator until C11. */
   1126 type_member_declarator:
   1127 	  type_declarator
   1128 	| type_declarator T_COLON constant_expression {
   1129 		$$ = set_bit_field_width($1, to_int_constant($3, true));
   1130 	  }
   1131 	| {
   1132 		set_symtyp(FVFT);
   1133 	  } T_COLON constant_expression {
   1134 		$$ = set_bit_field_width(NULL, to_int_constant($3, true));
   1135 	  }
   1136 	;
   1137 
   1138 /* K&R ---, C90 6.5.2.2, C99 6.7.2.2, C11 6.7.2.2 */
   1139 enum_specifier:
   1140 	  enum gcc_attribute_specifier_list_opt identifier_sym {
   1141 		$$ = make_tag_type($3, ENUM, false, false);
   1142 	  }
   1143 	| enum gcc_attribute_specifier_list_opt identifier_sym {
   1144 		dcs->d_tag_type = make_tag_type($3, ENUM, true, false);
   1145 	  } enum_declaration /*gcc_attribute_specifier_list_opt*/ {
   1146 		$$ = complete_enum($5);
   1147 	  }
   1148 	| enum gcc_attribute_specifier_list_opt {
   1149 		dcs->d_tag_type = make_tag_type(NULL, ENUM, true, false);
   1150 	  } enum_declaration /*gcc_attribute_specifier_list_opt*/ {
   1151 		$$ = complete_enum($4);
   1152 	  }
   1153 	| enum error {
   1154 		set_symtyp(FVFT);
   1155 		$$ = gettyp(INT);
   1156 	  }
   1157 	;
   1158 
   1159 enum:				/* helper for C99 6.7.2.2 */
   1160 	  T_ENUM {
   1161 		set_symtyp(FTAG);
   1162 		begin_declaration_level(DLK_ENUM);
   1163 	  }
   1164 	;
   1165 
   1166 enum_declaration:		/* helper for C99 6.7.2.2 */
   1167 	  enum_decl_lbrace enums_with_opt_comma T_RBRACE {
   1168 		$$ = $2;
   1169 	  }
   1170 	;
   1171 
   1172 enum_decl_lbrace:		/* helper for C99 6.7.2.2 */
   1173 	  T_LBRACE {
   1174 		set_symtyp(FVFT);
   1175 		enumval = 0;
   1176 	  }
   1177 	;
   1178 
   1179 enums_with_opt_comma:		/* helper for C99 6.7.2.2 */
   1180 	  enumerator_list
   1181 	| enumerator_list T_COMMA {
   1182 		if (!allow_c99 && !allow_trad) {
   1183 			/* trailing ',' in enum declaration requires C99 ... */
   1184 			error(54);
   1185 		} else {
   1186 			/* trailing ',' in enum declaration requires C99 ... */
   1187 			c99ism(54);
   1188 		}
   1189 		$$ = $1;
   1190 	  }
   1191 	;
   1192 
   1193 enumerator_list:		/* C99 6.7.2.2 */
   1194 	  enumerator
   1195 	| enumerator_list T_COMMA enumerator {
   1196 		$$ = concat_symbols($1, $3);
   1197 	  }
   1198 	| error {
   1199 		$$ = NULL;
   1200 	  }
   1201 	;
   1202 
   1203 enumerator:			/* C99 6.7.2.2 */
   1204 	  identifier_sym gcc_attribute_specifier_list_opt {
   1205 		$$ = enumeration_constant($1, enumval, true);
   1206 	  }
   1207 	| identifier_sym gcc_attribute_specifier_list_opt
   1208 	    T_ASSIGN constant_expression {
   1209 		$$ = enumeration_constant($1, to_int_constant($4, true),
   1210 		    false);
   1211 	  }
   1212 	;
   1213 
   1214 type_qualifier:			/* C99 6.7.3 */
   1215 	  T_QUAL
   1216 	| atomic {
   1217 		$$ = ATOMIC;
   1218 	  }
   1219 	;
   1220 
   1221 atomic:				/* helper */
   1222 	  T_ATOMIC {
   1223 		/* TODO: First fix c11ism, then use it here. */
   1224 		if (!allow_c11)
   1225 			/* '_Atomic' requires C11 or later */
   1226 			error(350);
   1227 	  }
   1228 	;
   1229 
   1230 pointer:			/* C99 6.7.5 */
   1231 	  asterisk type_qualifier_list_opt {
   1232 		$$ = merge_qualified_pointer($1, $2);
   1233 	  }
   1234 	| asterisk type_qualifier_list_opt pointer {
   1235 		$$ = merge_qualified_pointer($1, $2);
   1236 		$$ = merge_qualified_pointer($$, $3);
   1237 	  }
   1238 	;
   1239 
   1240 asterisk:			/* helper for 'pointer' */
   1241 	  T_ASTERISK {
   1242 		$$ = xcalloc(1, sizeof(*$$));
   1243 		$$->p_pointer = true;
   1244 	  }
   1245 	;
   1246 
   1247 type_qualifier_list_opt:	/* see C99 6.7.5 */
   1248 	  /* empty */ {
   1249 		$$ = NULL;
   1250 	  }
   1251 	| type_qualifier_list
   1252 	;
   1253 
   1254 type_qualifier_list:		/* C99 6.7.5 */
   1255 	  type_qualifier_list_elem
   1256 	| type_qualifier_list type_qualifier_list_elem {
   1257 		$$ = merge_qualified_pointer($1, $2);
   1258 	  }
   1259 	;
   1260 
   1261 type_qualifier_list_elem:	/* helper for 'pointer' */
   1262 	type_qualifier {
   1263 		$$ = xcalloc(1, sizeof(*$$));
   1264 		if ($1 == CONST)
   1265 			$$->p_const = true;
   1266 		if ($1 == VOLATILE)
   1267 			$$->p_volatile = true;
   1268 	  }
   1269 	;
   1270 
   1271 /*
   1272  * For an explanation of 'notype' in the following rules, see
   1273  * https://www.gnu.org/software/bison/manual/bison.html#Semantic-Tokens.
   1274  */
   1275 
   1276 notype_init_declarators:
   1277 	  notype_init_declarator
   1278 	| notype_init_declarators T_COMMA type_init_declarator
   1279 	;
   1280 
   1281 type_init_declarators:
   1282 	  type_init_declarator
   1283 	| type_init_declarators T_COMMA type_init_declarator
   1284 	;
   1285 
   1286 notype_init_declarator:
   1287 	  notype_declarator asm_or_symbolrename_opt {
   1288 		cgram_declare($1, false, $2);
   1289 		check_size($1);
   1290 	  }
   1291 	| notype_declarator asm_or_symbolrename_opt {
   1292 		begin_initialization($1);
   1293 		cgram_declare($1, true, $2);
   1294 	  } T_ASSIGN initializer {
   1295 		check_size($1);
   1296 		end_initialization();
   1297 	  }
   1298 	;
   1299 
   1300 type_init_declarator:
   1301 	  type_declarator asm_or_symbolrename_opt {
   1302 		cgram_declare($1, false, $2);
   1303 		check_size($1);
   1304 	  }
   1305 	| type_declarator asm_or_symbolrename_opt {
   1306 		begin_initialization($1);
   1307 		cgram_declare($1, true, $2);
   1308 	  } T_ASSIGN initializer {
   1309 		check_size($1);
   1310 		end_initialization();
   1311 	  }
   1312 	;
   1313 
   1314 notype_declarator:
   1315 	  notype_direct_declarator
   1316 	| pointer notype_direct_declarator {
   1317 		$$ = add_pointer($2, $1);
   1318 	  }
   1319 	;
   1320 
   1321 type_declarator:
   1322 	  type_direct_declarator
   1323 	| pointer type_direct_declarator {
   1324 		$$ = add_pointer($2, $1);
   1325 	  }
   1326 	;
   1327 
   1328 notype_direct_declarator:
   1329 	  type_attribute_list_opt T_NAME {
   1330 		$$ = declarator_name(getsym($2));
   1331 	  }
   1332 	| type_attribute_list_opt T_LPAREN type_declarator T_RPAREN {
   1333 		$$ = $3;
   1334 	  }
   1335 	| notype_direct_declarator T_LBRACK array_size_opt T_RBRACK {
   1336 		$$ = add_array($1, $3.has_dim, $3.dim);
   1337 	  }
   1338 	| notype_direct_declarator param_list asm_or_symbolrename_opt {
   1339 		$$ = add_function(symbolrename($1, $3), $2);
   1340 		end_declaration_level();
   1341 		block_level--;
   1342 	  }
   1343 	| notype_direct_declarator type_attribute
   1344 	;
   1345 
   1346 type_direct_declarator:
   1347 	  type_attribute_list_opt identifier {
   1348 		$$ = declarator_name(getsym($2));
   1349 	  }
   1350 	| type_attribute_list_opt T_LPAREN type_declarator T_RPAREN {
   1351 		$$ = $3;
   1352 	  }
   1353 	| type_direct_declarator T_LBRACK array_size_opt T_RBRACK {
   1354 		$$ = add_array($1, $3.has_dim, $3.dim);
   1355 	  }
   1356 	| type_direct_declarator param_list asm_or_symbolrename_opt {
   1357 		$$ = add_function(symbolrename($1, $3), $2);
   1358 		end_declaration_level();
   1359 		block_level--;
   1360 	  }
   1361 	| type_direct_declarator type_attribute
   1362 	;
   1363 
   1364 /*
   1365  * The two distinct rules type_param_declarator and notype_param_declarator
   1366  * avoid a conflict in argument lists. A typename enclosed in parentheses is
   1367  * always treated as a typename, not an argument name. For example, after
   1368  * "typedef double a;", the declaration "f(int (a));" is interpreted as
   1369  * "f(int (double));", not "f(int a);".
   1370  */
   1371 type_param_declarator:
   1372 	  direct_param_declarator
   1373 	| pointer direct_param_declarator {
   1374 		$$ = add_pointer($2, $1);
   1375 	  }
   1376 	;
   1377 
   1378 notype_param_declarator:
   1379 	  direct_notype_param_declarator
   1380 	| pointer direct_notype_param_declarator {
   1381 		$$ = add_pointer($2, $1);
   1382 	  }
   1383 	;
   1384 
   1385 direct_param_declarator:
   1386 	  identifier type_attribute_list {
   1387 		$$ = declarator_name(getsym($1));
   1388 	  }
   1389 	| identifier {
   1390 		$$ = declarator_name(getsym($1));
   1391 	  }
   1392 	| T_LPAREN notype_param_declarator T_RPAREN {
   1393 		$$ = $2;
   1394 	  }
   1395 	| direct_param_declarator T_LBRACK array_size_opt T_RBRACK
   1396 	    gcc_attribute_specifier_list_opt {
   1397 		$$ = add_array($1, $3.has_dim, $3.dim);
   1398 	  }
   1399 	| direct_param_declarator param_list asm_or_symbolrename_opt {
   1400 		$$ = add_function(symbolrename($1, $3), $2);
   1401 		end_declaration_level();
   1402 		block_level--;
   1403 	  }
   1404 	;
   1405 
   1406 direct_notype_param_declarator:
   1407 	  identifier {
   1408 		$$ = declarator_name(getsym($1));
   1409 	  }
   1410 	| T_LPAREN notype_param_declarator T_RPAREN {
   1411 		$$ = $2;
   1412 	  }
   1413 	| direct_notype_param_declarator T_LBRACK array_size_opt T_RBRACK {
   1414 		$$ = add_array($1, $3.has_dim, $3.dim);
   1415 	  }
   1416 	| direct_notype_param_declarator param_list asm_or_symbolrename_opt {
   1417 		$$ = add_function(symbolrename($1, $3), $2);
   1418 		end_declaration_level();
   1419 		block_level--;
   1420 	  }
   1421 	;
   1422 
   1423 param_list:
   1424 	  id_list_lparen identifier_list T_RPAREN {
   1425 		$$ = $2;
   1426 	  }
   1427 	| abstract_decl_param_list
   1428 	;
   1429 
   1430 id_list_lparen:
   1431 	  T_LPAREN {
   1432 		block_level++;
   1433 		begin_declaration_level(DLK_PROTO_PARAMS);
   1434 	  }
   1435 	;
   1436 
   1437 array_size_opt:
   1438 	  /* empty */ {
   1439 		$$.has_dim = false;
   1440 		$$.dim = 0;
   1441 	  }
   1442 	| T_ASTERISK {
   1443 		/* since C99; variable length array of unspecified size */
   1444 		$$.has_dim = false; /* TODO: maybe change to true */
   1445 		$$.dim = 0;	/* just as a placeholder */
   1446 	  }
   1447 	| array_size {
   1448 		$$.has_dim = true;
   1449 		$$.dim = $1 == NULL ? 0 : to_int_constant($1, false);
   1450 	  }
   1451 	;
   1452 
   1453 array_size:
   1454 	  type_qualifier_list_opt T_SCLASS constant_expression {
   1455 		/* C11 6.7.6.3p7 */
   1456 		if ($2 != STATIC)
   1457 			yyerror("Bad attribute");
   1458 		/* static array size is a C11 extension */
   1459 		c11ism(343);
   1460 		$$ = $3;
   1461 	  }
   1462 	| type_qualifier {
   1463 		/* C11 6.7.6.2 */
   1464 		if ($1 != RESTRICT)
   1465 			yyerror("Bad attribute");
   1466 		$$ = NULL;
   1467 	  }
   1468 	| constant_expression
   1469 	;
   1470 
   1471 identifier_list:		/* C99 6.7.5 */
   1472 	  T_NAME {
   1473 		$$ = old_style_function_parameter_name(getsym($1));
   1474 	  }
   1475 	| identifier_list T_COMMA T_NAME {
   1476 		$$ = concat_symbols($1,
   1477 		    old_style_function_parameter_name(getsym($3)));
   1478 	  }
   1479 	| identifier_list error
   1480 	;
   1481 
   1482 /* XXX: C99 requires an additional specifier-qualifier-list. */
   1483 type_name:			/* C99 6.7.6 */
   1484 	  {
   1485 		begin_declaration_level(DLK_ABSTRACT);
   1486 	  } abstract_declaration {
   1487 		end_declaration_level();
   1488 		$$ = $2->s_type;
   1489 	  }
   1490 	;
   1491 
   1492 abstract_declaration:		/* specific to lint */
   1493 	  begin_type_qualifier_list end_type {
   1494 		$$ = declare_abstract_type(abstract_name());
   1495 	  }
   1496 	| begin_type_specifier_qualifier_list end_type {
   1497 		$$ = declare_abstract_type(abstract_name());
   1498 	  }
   1499 	| begin_type_qualifier_list end_type abstract_declarator {
   1500 		$$ = declare_abstract_type($3);
   1501 	  }
   1502 	| begin_type_specifier_qualifier_list end_type abstract_declarator {
   1503 		$$ = declare_abstract_type($3);
   1504 	  }
   1505 	;
   1506 
   1507 /* K&R 8.7, C90 ???, C99 6.7.6, C11 6.7.7 */
   1508 /* In K&R, abstract-declarator could be empty and was still simpler. */
   1509 abstract_declarator:
   1510 	  pointer {
   1511 		$$ = add_pointer(abstract_name(), $1);
   1512 	  }
   1513 	| direct_abstract_declarator
   1514 	| pointer direct_abstract_declarator {
   1515 		$$ = add_pointer($2, $1);
   1516 	  }
   1517 	| type_attribute_list direct_abstract_declarator {
   1518 		$$ = $2;
   1519 	  }
   1520 	| pointer type_attribute_list direct_abstract_declarator {
   1521 		$$ = add_pointer($3, $1);
   1522 	  }
   1523 	;
   1524 
   1525 /* K&R ---, C90 ???, C99 6.7.6, C11 6.7.7 */
   1526 direct_abstract_declarator:
   1527 	/* TODO: sort rules according to C99 */
   1528 	  T_LPAREN abstract_declarator T_RPAREN {
   1529 		$$ = $2;
   1530 	  }
   1531 	| T_LBRACK array_size_opt T_RBRACK {
   1532 		$$ = add_array(abstract_name(), $2.has_dim, $2.dim);
   1533 	  }
   1534 	| direct_abstract_declarator T_LBRACK array_size_opt T_RBRACK {
   1535 		$$ = add_array($1, $3.has_dim, $3.dim);
   1536 	  }
   1537 	| abstract_decl_param_list asm_or_symbolrename_opt {
   1538 		$$ = add_function(symbolrename(abstract_name(), $2), $1);
   1539 		end_declaration_level();
   1540 		block_level--;
   1541 	  }
   1542 	| direct_abstract_declarator abstract_decl_param_list
   1543 	    asm_or_symbolrename_opt {
   1544 		$$ = add_function(symbolrename($1, $3), $2);
   1545 		end_declaration_level();
   1546 		block_level--;
   1547 	  }
   1548 	| direct_abstract_declarator type_attribute_list
   1549 	;
   1550 
   1551 abstract_decl_param_list:	/* specific to lint */
   1552 	  abstract_decl_lparen T_RPAREN type_attribute_opt {
   1553 		$$ = NULL;
   1554 	  }
   1555 	| abstract_decl_lparen vararg_parameter_type_list T_RPAREN
   1556 	    type_attribute_opt {
   1557 		dcs->d_prototype = true;
   1558 		$$ = $2;
   1559 	  }
   1560 	| abstract_decl_lparen error T_RPAREN type_attribute_opt {
   1561 		$$ = NULL;
   1562 	  }
   1563 	;
   1564 
   1565 abstract_decl_lparen:		/* specific to lint */
   1566 	  T_LPAREN {
   1567 		block_level++;
   1568 		begin_declaration_level(DLK_PROTO_PARAMS);
   1569 	  }
   1570 	;
   1571 
   1572 vararg_parameter_type_list:	/* specific to lint */
   1573 	  parameter_type_list
   1574 	| parameter_type_list T_COMMA T_ELLIPSIS {
   1575 		dcs->d_vararg = true;
   1576 		$$ = $1;
   1577 	  }
   1578 	| T_ELLIPSIS {
   1579 		/* TODO: C99 6.7.5 makes this an error as well. */
   1580 		if (!allow_trad && !allow_c99) {
   1581 			/* ANSI C requires formal parameter before '...' */
   1582 			error(84);
   1583 		} else if (allow_c90) {
   1584 			/* ANSI C requires formal parameter before '...' */
   1585 			warning(84);
   1586 		}
   1587 		dcs->d_vararg = true;
   1588 		$$ = NULL;
   1589 	  }
   1590 	;
   1591 
   1592 /* XXX: C99 6.7.5 defines the same name, but it looks different. */
   1593 parameter_type_list:
   1594 	  parameter_declaration
   1595 	| parameter_type_list T_COMMA parameter_declaration {
   1596 		$$ = concat_symbols($1, $3);
   1597 	  }
   1598 	;
   1599 
   1600 /* XXX: C99 6.7.5 defines the same name, but it looks completely different. */
   1601 parameter_declaration:
   1602 	  begin_type_declmods end_type {
   1603 		/* ^^ There is no check for the missing type-specifier. */
   1604 		$$ = declare_argument(abstract_name(), false);
   1605 	  }
   1606 	| begin_type_declaration_specifiers end_type {
   1607 		$$ = declare_argument(abstract_name(), false);
   1608 	  }
   1609 	| begin_type_declmods end_type notype_param_declarator {
   1610 		/* ^^ There is no check for the missing type-specifier. */
   1611 		$$ = declare_argument($3, false);
   1612 	  }
   1613 	/*
   1614 	 * type_param_declarator is needed because of following conflict:
   1615 	 * "typedef int a; f(int (a));" could be parsed as
   1616 	 * "function with argument a of type int", or
   1617 	 * "function with an abstract argument of type function".
   1618 	 * This grammar realizes the second case.
   1619 	 */
   1620 	| begin_type_declaration_specifiers end_type type_param_declarator {
   1621 		$$ = declare_argument($3, false);
   1622 	  }
   1623 	| begin_type_declmods end_type abstract_declarator {
   1624 		/* ^^ There is no check for the missing type-specifier. */
   1625 		$$ = declare_argument($3, false);
   1626 	  }
   1627 	| begin_type_declaration_specifiers end_type abstract_declarator {
   1628 		$$ = declare_argument($3, false);
   1629 	  }
   1630 	;
   1631 
   1632 braced_initializer:
   1633 	/* K&R ---, C90 ---, C99 ---, C11 ---, C23 6.7.10 */
   1634 	  init_lbrace init_rbrace {
   1635 		/* empty initializer braces require C23 or later */
   1636 		c23ism(353);
   1637 	}
   1638 	/* K&R ---, C90 ---, C99 6.7.8, C11 6.7.9, C23 6.7.10 */
   1639 	| init_lbrace initializer_list comma_opt init_rbrace
   1640 	;
   1641 
   1642 initializer:			/* C99 6.7.8 "Initialization" */
   1643 	  assignment_expression {
   1644 		init_expr($1);
   1645 	  }
   1646 	| init_lbrace init_rbrace {
   1647 		/* XXX: Empty braces are not covered by C99 6.7.8. */
   1648 	  }
   1649 	| init_lbrace initializer_list comma_opt init_rbrace
   1650 	  /* XXX: What is this error handling for? */
   1651 	| error
   1652 	;
   1653 
   1654 initializer_list:		/* C99 6.7.8 "Initialization" */
   1655 	  initializer_list_item
   1656 	| initializer_list T_COMMA initializer_list_item
   1657 	;
   1658 
   1659 initializer_list_item:		/* helper */
   1660 	  designation initializer
   1661 	| initializer
   1662 	;
   1663 
   1664 designation:			/* C99 6.7.8 "Initialization" */
   1665 	  begin_designation designator_list T_ASSIGN
   1666 	| identifier T_COLON {
   1667 		/* GCC style struct or union member name in initializer */
   1668 		gnuism(315);
   1669 		begin_designation();
   1670 		add_designator_member($1);
   1671 	  }
   1672 	;
   1673 
   1674 begin_designation:		/* lint-specific helper */
   1675 	  /* empty */ {
   1676 		begin_designation();
   1677 	  }
   1678 	;
   1679 
   1680 designator_list:		/* C99 6.7.8 "Initialization" */
   1681 	  designator
   1682 	| designator_list designator
   1683 	;
   1684 
   1685 designator:			/* C99 6.7.8 "Initialization" */
   1686 	  T_LBRACK range T_RBRACK {
   1687 		if (!allow_c99)
   1688 			/* array initializer with designators is a C99 ... */
   1689 			warning(321);
   1690 		add_designator_subscript($2);
   1691 	  }
   1692 	| T_POINT identifier {
   1693 		if (!allow_c99)
   1694 			/* struct or union member name in initializer is ... */
   1695 			warning(313);
   1696 		add_designator_member($2);
   1697 	  }
   1698 	;
   1699 
   1700 static_assert_declaration:
   1701 	  T_STATIC_ASSERT T_LPAREN
   1702 	    constant_expression T_COMMA T_STRING T_RPAREN T_SEMI /* C11 */
   1703 	| T_STATIC_ASSERT T_LPAREN constant_expression T_RPAREN T_SEMI /* C23 */
   1704 	;
   1705 
   1706 range:
   1707 	  constant_expression {
   1708 		$$.lo = to_int_constant($1, true);
   1709 		$$.hi = $$.lo;
   1710 	  }
   1711 	| constant_expression T_ELLIPSIS constant_expression {
   1712 		$$.lo = to_int_constant($1, true);
   1713 		$$.hi = to_int_constant($3, true);
   1714 		/* initialization with '[a...b]' is a GCC extension */
   1715 		gnuism(340);
   1716 	  }
   1717 	;
   1718 
   1719 init_lbrace:			/* helper */
   1720 	  T_LBRACE {
   1721 		init_lbrace();
   1722 	  }
   1723 	;
   1724 
   1725 init_rbrace:			/* helper */
   1726 	  T_RBRACE {
   1727 		init_rbrace();
   1728 	  }
   1729 	;
   1730 
   1731 asm_or_symbolrename_opt:	/* GCC extensions */
   1732 	  /* empty */ {
   1733 		$$ = NULL;
   1734 	  }
   1735 	| T_ASM T_LPAREN T_STRING T_RPAREN gcc_attribute_specifier_list_opt {
   1736 		freeyyv(&$3, T_STRING);
   1737 		$$ = NULL;
   1738 	  }
   1739 	| T_SYMBOLRENAME T_LPAREN T_NAME T_RPAREN
   1740 	    gcc_attribute_specifier_list_opt {
   1741 		$$ = $3;
   1742 	  }
   1743 	;
   1744 
   1745 /* K&R ???, C90 ???, C99 6.8, C11 ???, C23 6.8 */
   1746 statement:
   1747 	  expression_statement
   1748 	| non_expr_statement
   1749 	;
   1750 
   1751 non_expr_statement:		/* helper for C99 6.8 */
   1752 	  gcc_attribute_specifier /* ((__fallthrough__)) */ T_SEMI
   1753 	| labeled_statement
   1754 	| compound_statement
   1755 	| selection_statement
   1756 	| iteration_statement
   1757 	| jump_statement {
   1758 		seen_fallthrough = false;
   1759 	  }
   1760 	| asm_statement
   1761 	;
   1762 
   1763 labeled_statement:		/* C99 6.8.1 */
   1764 	  label gcc_attribute_specifier_list_opt statement
   1765 	;
   1766 
   1767 label:
   1768 	  T_NAME T_COLON {
   1769 		set_symtyp(FLABEL);
   1770 		named_label(getsym($1));
   1771 	  }
   1772 	| T_CASE constant_expression T_COLON {
   1773 		case_label($2);
   1774 		seen_fallthrough = true;
   1775 	  }
   1776 	| T_CASE constant_expression T_ELLIPSIS constant_expression T_COLON {
   1777 		/* XXX: We don't fill all cases */
   1778 		case_label($2);
   1779 		seen_fallthrough = true;
   1780 	  }
   1781 	| T_DEFAULT T_COLON {
   1782 		default_label();
   1783 		seen_fallthrough = true;
   1784 	  }
   1785 	;
   1786 
   1787 compound_statement:		/* C99 6.8.2 */
   1788 	  compound_statement_lbrace compound_statement_rbrace
   1789 	| compound_statement_lbrace block_item_list compound_statement_rbrace
   1790 	;
   1791 
   1792 compound_statement_lbrace:
   1793 	  T_LBRACE {
   1794 		block_level++;
   1795 		mem_block_level++;
   1796 		begin_declaration_level(DLK_AUTO);
   1797 	  }
   1798 	;
   1799 
   1800 compound_statement_rbrace:
   1801 	  T_RBRACE {
   1802 		end_declaration_level();
   1803 		level_free_all(mem_block_level);
   1804 		mem_block_level--;
   1805 		block_level--;
   1806 		seen_fallthrough = false;
   1807 	  }
   1808 	;
   1809 
   1810 block_item_list:		/* C99 6.8.2 */
   1811 	  block_item
   1812 	| block_item_list block_item {
   1813 		if ($1 && !$2)
   1814 			/* declarations after statements is a C99 feature */
   1815 			c99ism(327);
   1816 		$$ = $1 || $2;
   1817 	  }
   1818 	;
   1819 
   1820 block_item:			/* C99 6.8.2 */
   1821 	  declaration_or_error {
   1822 		$$ = false;
   1823 		restore_warning_flags();
   1824 	  }
   1825 	| statement {
   1826 		$$ = true;
   1827 		restore_warning_flags();
   1828 	  }
   1829 	;
   1830 
   1831 expression_statement:		/* C99 6.8.3 */
   1832 	  expression T_SEMI {
   1833 		expr($1, false, false, false, false);
   1834 		seen_fallthrough = false;
   1835 	  }
   1836 	| T_SEMI {
   1837 		check_statement_reachable();
   1838 		seen_fallthrough = false;
   1839 	  }
   1840 	;
   1841 
   1842 selection_statement:		/* C99 6.8.4 */
   1843 	  if_without_else %prec T_THEN {
   1844 		save_warning_flags();
   1845 		stmt_if_then_stmt();
   1846 		stmt_if_else_stmt(false);
   1847 	  }
   1848 	| if_without_else T_ELSE {
   1849 		save_warning_flags();
   1850 		stmt_if_then_stmt();
   1851 	  } statement {
   1852 		clear_warning_flags();
   1853 		stmt_if_else_stmt(true);
   1854 	  }
   1855 	| if_without_else T_ELSE error {
   1856 		clear_warning_flags();
   1857 		stmt_if_else_stmt(false);
   1858 	  }
   1859 	| switch_expr statement {
   1860 		clear_warning_flags();
   1861 		stmt_switch_expr_stmt();
   1862 	  }
   1863 	| switch_expr error {
   1864 		clear_warning_flags();
   1865 		stmt_switch_expr_stmt();
   1866 	  }
   1867 	;
   1868 
   1869 if_without_else:		/* see C99 6.8.4 */
   1870 	  if_expr statement
   1871 	| if_expr error
   1872 	;
   1873 
   1874 if_expr:			/* see C99 6.8.4 */
   1875 	  T_IF T_LPAREN expression T_RPAREN {
   1876 		stmt_if_expr($3);
   1877 		clear_warning_flags();
   1878 	  }
   1879 	;
   1880 
   1881 switch_expr:			/* see C99 6.8.4 */
   1882 	  T_SWITCH T_LPAREN expression T_RPAREN {
   1883 		stmt_switch_expr($3);
   1884 		clear_warning_flags();
   1885 	  }
   1886 	;
   1887 
   1888 iteration_statement:		/* C99 6.8.5 */
   1889 	  while_expr statement {
   1890 		clear_warning_flags();
   1891 		stmt_while_expr_stmt();
   1892 	  }
   1893 	| while_expr error {
   1894 		clear_warning_flags();
   1895 		stmt_while_expr_stmt();
   1896 	  }
   1897 	| do_statement do_while_expr {
   1898 		stmt_do_while_expr($2);
   1899 		seen_fallthrough = false;
   1900 	  }
   1901 	| do error {
   1902 		clear_warning_flags();
   1903 		stmt_do_while_expr(NULL);
   1904 	  }
   1905 	| for_exprs statement {
   1906 		clear_warning_flags();
   1907 		stmt_for_exprs_stmt();
   1908 		end_declaration_level();
   1909 		block_level--;
   1910 	  }
   1911 	| for_exprs error {
   1912 		clear_warning_flags();
   1913 		stmt_for_exprs_stmt();
   1914 		end_declaration_level();
   1915 		block_level--;
   1916 	  }
   1917 	;
   1918 
   1919 while_expr:			/* see C99 6.8.5 */
   1920 	  T_WHILE T_LPAREN expression T_RPAREN {
   1921 		stmt_while_expr($3);
   1922 		clear_warning_flags();
   1923 	  }
   1924 	;
   1925 
   1926 do_statement:			/* see C99 6.8.5 */
   1927 	  do statement {
   1928 		clear_warning_flags();
   1929 	  }
   1930 	;
   1931 
   1932 do:				/* see C99 6.8.5 */
   1933 	  T_DO {
   1934 		stmt_do();
   1935 	  }
   1936 	;
   1937 
   1938 do_while_expr:			/* see C99 6.8.5 */
   1939 	  T_WHILE T_LPAREN expression T_RPAREN T_SEMI {
   1940 		$$ = $3;
   1941 	  }
   1942 	;
   1943 
   1944 for_start:			/* see C99 6.8.5 */
   1945 	  T_FOR T_LPAREN {
   1946 		begin_declaration_level(DLK_AUTO);
   1947 		block_level++;
   1948 	  }
   1949 	;
   1950 
   1951 for_exprs:			/* see C99 6.8.5 */
   1952 	  for_start
   1953 	    begin_type_declaration_specifiers end_type
   1954 	    notype_init_declarators T_SEMI
   1955 	    expression_opt T_SEMI
   1956 	    expression_opt T_RPAREN {
   1957 		/* variable declaration in for loop */
   1958 		c99ism(325);
   1959 		stmt_for_exprs(NULL, $6, $8);
   1960 		clear_warning_flags();
   1961 	    }
   1962 	| for_start
   1963 	    expression_opt T_SEMI
   1964 	    expression_opt T_SEMI
   1965 	    expression_opt T_RPAREN {
   1966 		stmt_for_exprs($2, $4, $6);
   1967 		clear_warning_flags();
   1968 	  }
   1969 	;
   1970 
   1971 jump_statement:			/* C99 6.8.6 */
   1972 	  goto identifier T_SEMI {
   1973 		stmt_goto(getsym($2));
   1974 	  }
   1975 	| goto error T_SEMI {
   1976 		set_symtyp(FVFT);
   1977 	  }
   1978 	| T_CONTINUE T_SEMI {
   1979 		stmt_continue();
   1980 	  }
   1981 	| T_BREAK T_SEMI {
   1982 		stmt_break();
   1983 	  }
   1984 	| T_RETURN sys T_SEMI {
   1985 		stmt_return($2, NULL);
   1986 	  }
   1987 	| T_RETURN sys expression T_SEMI {
   1988 		stmt_return($2, $3);
   1989 	  }
   1990 	;
   1991 
   1992 goto:				/* see C99 6.8.6 */
   1993 	  T_GOTO {
   1994 		set_symtyp(FLABEL);
   1995 	  }
   1996 	;
   1997 
   1998 asm_statement:			/* GCC extension */
   1999 	  T_ASM T_LPAREN read_until_rparen T_SEMI {
   2000 		dcs_set_asm();
   2001 	  }
   2002 	| T_ASM type_qualifier T_LPAREN read_until_rparen T_SEMI {
   2003 		dcs_set_asm();
   2004 	  }
   2005 	| T_ASM error
   2006 	;
   2007 
   2008 read_until_rparen:		/* helper for 'asm_statement' */
   2009 	  /* empty */ {
   2010 		read_until_rparen();
   2011 	  }
   2012 	;
   2013 
   2014 translation_unit:		/* C99 6.9 */
   2015 	  external_declaration
   2016 	| translation_unit external_declaration
   2017 	;
   2018 
   2019 external_declaration:		/* C99 6.9 */
   2020 	  function_definition {
   2021 		global_clean_up_decl(false);
   2022 		clear_warning_flags();
   2023 	  }
   2024 	| top_level_declaration {
   2025 		global_clean_up_decl(false);
   2026 		clear_warning_flags();
   2027 	  }
   2028 	| asm_statement		/* GCC extension */
   2029 	| T_SEMI {		/* GCC extension */
   2030 		/*
   2031 		 * TODO: Only allow this in GCC mode, not in plain C99.
   2032 		 * This is one of the top 10 warnings in the NetBSD build.
   2033 		 */
   2034 		if (!allow_trad && !allow_c99) {
   2035 			/* empty declaration */
   2036 			error(0);
   2037 		} else if (allow_c90) {
   2038 			/* empty declaration */
   2039 			warning(0);
   2040 		}
   2041 	  }
   2042 	;
   2043 
   2044 /*
   2045  * On the top level, lint allows several forms of declarations that it doesn't
   2046  * allow in functions.  For example, a single ';' is an empty declaration and
   2047  * is supported by some compilers, but in a function it would be an empty
   2048  * statement, not a declaration.  This makes a difference in C90 mode, where
   2049  * a statement must not be followed by a declaration.
   2050  *
   2051  * See 'declaration' for all other declarations.
   2052  */
   2053 top_level_declaration:		/* C99 6.9 calls this 'declaration' */
   2054 	  begin_type end_type notype_init_declarators T_SEMI {
   2055 		/* TODO: Make this an error in C99 mode as well. */
   2056 		if (!allow_trad && !allow_c99) {
   2057 			/* old-style declaration; add 'int' */
   2058 			error(1);
   2059 		} else if (allow_c90) {
   2060 			/* old-style declaration; add 'int' */
   2061 			warning(1);
   2062 		}
   2063 	  }
   2064 	| declaration
   2065 	| error T_SEMI {
   2066 		global_clean_up();
   2067 	  }
   2068 	| error T_RBRACE {
   2069 		global_clean_up();
   2070 	  }
   2071 	;
   2072 
   2073 function_definition:		/* C99 6.9.1 */
   2074 	  func_declarator {
   2075 		if ($1->s_type->t_tspec != FUNC) {
   2076 			/* syntax error '%s' */
   2077 			error(249, yytext);
   2078 			YYERROR;
   2079 		}
   2080 		if ($1->s_type->t_typedef) {
   2081 			/* ()-less function definition */
   2082 			error(64);
   2083 			YYERROR;
   2084 		}
   2085 		check_extern_declaration($1);
   2086 		begin_function($1);
   2087 		block_level++;
   2088 		begin_declaration_level(DLK_OLD_STYLE_ARGS);
   2089 		if (lwarn == LWARN_NONE)
   2090 			$1->s_used = true;
   2091 	  } arg_declaration_list_opt {
   2092 		end_declaration_level();
   2093 		block_level--;
   2094 		check_func_lint_directives();
   2095 		check_func_old_style_arguments();
   2096 		begin_control_statement(CS_FUNCTION_BODY);
   2097 	  } compound_statement {
   2098 		end_function();
   2099 		end_control_statement(CS_FUNCTION_BODY);
   2100 	  }
   2101 	;
   2102 
   2103 func_declarator:
   2104 	  begin_type end_type notype_declarator {
   2105 		if (!allow_trad) {
   2106 			/* old-style declaration; add 'int' */
   2107 			error(1);
   2108 		}
   2109 		$$ = $3;
   2110 	  }
   2111 	| begin_type_declmods end_type notype_declarator {
   2112 		if (!allow_trad) {
   2113 			/* old-style declaration; add 'int' */
   2114 			error(1);
   2115 		}
   2116 		$$ = $3;
   2117 	  }
   2118 	| begin_type_declaration_specifiers end_type type_declarator {
   2119 		$$ = $3;
   2120 	  }
   2121 	;
   2122 
   2123 arg_declaration_list_opt:	/* C99 6.9.1p13 example 1 */
   2124 	  /* empty */
   2125 	| arg_declaration_list
   2126 	;
   2127 
   2128 arg_declaration_list:		/* C99 6.9.1p13 example 1 */
   2129 	  arg_declaration
   2130 	| arg_declaration_list arg_declaration
   2131 	/* XXX or better "arg_declaration error" ? */
   2132 	| error
   2133 	;
   2134 
   2135 /*
   2136  * "arg_declaration" is separated from "declaration" because it
   2137  * needs other error handling.
   2138  */
   2139 arg_declaration:
   2140 	  begin_type_declmods end_type T_SEMI {
   2141 		/* empty declaration */
   2142 		warning(2);
   2143 	  }
   2144 	| begin_type_declmods end_type notype_init_declarators T_SEMI
   2145 	| begin_type_declaration_specifiers end_type T_SEMI {
   2146 		if (!dcs->d_nonempty_decl) {
   2147 			/* empty declaration */
   2148 			warning(2);
   2149 		} else {
   2150 			/* '%s' declared in argument declaration list */
   2151 			warning(3, type_name(dcs->d_type));
   2152 		}
   2153 	  }
   2154 	| begin_type_declaration_specifiers end_type
   2155 	    type_init_declarators T_SEMI {
   2156 		if (dcs->d_nonempty_decl) {
   2157 			/* '%s' declared in argument declaration list */
   2158 			warning(3, type_name(dcs->d_type));
   2159 		}
   2160 	  }
   2161 	| begin_type_declmods error
   2162 	| begin_type_declaration_specifiers error
   2163 	;
   2164 
   2165 /* https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html */
   2166 gcc_attribute_specifier_list_opt:
   2167 	  /* empty */
   2168 	| gcc_attribute_specifier_list
   2169 	;
   2170 
   2171 gcc_attribute_specifier_list:
   2172 	  gcc_attribute_specifier
   2173 	| gcc_attribute_specifier_list gcc_attribute_specifier
   2174 	;
   2175 
   2176 gcc_attribute_specifier:
   2177 	  T_ATTRIBUTE T_LPAREN T_LPAREN {
   2178 		in_gcc_attribute = true;
   2179 	  } gcc_attribute_list {
   2180 		in_gcc_attribute = false;
   2181 	  } T_RPAREN T_RPAREN
   2182 	;
   2183 
   2184 gcc_attribute_list:
   2185 	  gcc_attribute
   2186 	| gcc_attribute_list T_COMMA gcc_attribute
   2187 	;
   2188 
   2189 gcc_attribute:
   2190 	  /* empty */
   2191 	| T_NAME {
   2192 		const char *name = $1->sb_name;
   2193 		if (is_either(name, "packed", "__packed__"))
   2194 			dcs_add_packed();
   2195 		else if (is_either(name, "used", "__used__") ||
   2196 		    is_either(name, "unused", "__unused__"))
   2197 			dcs_set_used();
   2198 		else if (is_either(name, "fallthrough", "__fallthrough__"))
   2199 			fallthru(1);
   2200 	}
   2201 	| T_NAME T_LPAREN T_RPAREN
   2202 	| T_NAME T_LPAREN gcc_attribute_parameters T_RPAREN
   2203 	| type_qualifier {
   2204 		if ($1 != CONST)
   2205 			yyerror("Bad attribute");
   2206 	  }
   2207 	;
   2208 
   2209 gcc_attribute_parameters:
   2210 	  constant_expression
   2211 	| gcc_attribute_parameters T_COMMA constant_expression
   2212 	;
   2213 
   2214 sys:
   2215 	  /* empty */ {
   2216 		$$ = in_system_header;
   2217 	  }
   2218 	;
   2219 
   2220 %%
   2221 
   2222 /* ARGSUSED */
   2223 int
   2224 yyerror(const char *msg)
   2225 {
   2226 	/* syntax error '%s' */
   2227 	error(249, yytext);
   2228 	if (++sytxerr >= 5)
   2229 		norecover();
   2230 	return 0;
   2231 }
   2232 
   2233 #if YYDEBUG && YYBYACC
   2234 static const char *
   2235 cgram_to_string(int token, YYSTYPE val)
   2236 {
   2237 
   2238 	switch (token) {
   2239 	case T_INCDEC:
   2240 	case T_MULTIPLICATIVE:
   2241 	case T_ADDITIVE:
   2242 	case T_SHIFT:
   2243 	case T_RELATIONAL:
   2244 	case T_EQUALITY:
   2245 	case T_OPASSIGN:
   2246 		return op_name(val.y_op);
   2247 	case T_SCLASS:
   2248 		return scl_name(val.y_scl);
   2249 	case T_TYPE:
   2250 	case T_STRUCT_OR_UNION:
   2251 		return tspec_name(val.y_tspec);
   2252 	case T_QUAL:
   2253 		return tqual_name(val.y_tqual);
   2254 	case T_NAME:
   2255 		return val.y_name->sb_name;
   2256 	default:
   2257 		return "<none>";
   2258 	}
   2259 }
   2260 #endif
   2261 
   2262 static void
   2263 cgram_declare(sym_t *decl, bool has_initializer, sbuf_t *renaming)
   2264 {
   2265 	declare(decl, has_initializer, renaming);
   2266 	if (renaming != NULL)
   2267 		freeyyv(&renaming, T_NAME);
   2268 }
   2269 
   2270 /*
   2271  * Discard all input tokens up to and including the next
   2272  * unmatched right paren
   2273  */
   2274 static void
   2275 read_until_rparen(void)
   2276 {
   2277 	int	level;
   2278 
   2279 	if (yychar < 0)
   2280 		yychar = yylex();
   2281 	freeyyv(&yylval, yychar);
   2282 
   2283 	level = 1;
   2284 	while (yychar > 0) {
   2285 		if (yychar == T_LPAREN)
   2286 			level++;
   2287 		if (yychar == T_RPAREN && --level == 0)
   2288 			break;
   2289 		freeyyv(&yylval, yychar = yylex());
   2290 	}
   2291 
   2292 	yyclearin;
   2293 }
   2294 
   2295 static	sym_t *
   2296 symbolrename(sym_t *s, sbuf_t *sb)
   2297 {
   2298 	if (sb != NULL)
   2299 		s->s_rename = sb->sb_name;
   2300 	return s;
   2301 }
   2302