xref: /netbsd-src/usr.bin/xlint/lint1/lex.c (revision a8016b51bcf5204ff836e46c2432dc27e5b12586)
1 /* $NetBSD: lex.c,v 1.232 2024/12/08 17:12:01 rillig Exp $ */
2 
3 /*
4  * Copyright (c) 1996 Christopher G. Demetriou.  All Rights Reserved.
5  * Copyright (c) 1994, 1995 Jochen Pohl
6  * All Rights Reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by Jochen Pohl for
19  *	The NetBSD Project.
20  * 4. The name of the author may not be used to endorse or promote products
21  *    derived from this software without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33  */
34 
35 #if HAVE_NBTOOL_CONFIG_H
36 #include "nbtool_config.h"
37 #endif
38 
39 #include <sys/cdefs.h>
40 #if defined(__RCSID)
41 __RCSID("$NetBSD: lex.c,v 1.232 2024/12/08 17:12:01 rillig Exp $");
42 #endif
43 
44 #include <ctype.h>
45 #include <errno.h>
46 #include <float.h>
47 #include <limits.h>
48 #include <math.h>
49 #include <stdlib.h>
50 #include <string.h>
51 
52 #include "lint1.h"
53 #include "cgram.h"
54 
55 #define CHAR_MASK	((1U << CHAR_SIZE) - 1)
56 
57 
58 /* Current position (it's also updated when an included file is parsed) */
59 pos_t curr_pos = { "", 1, 0 };
60 
61 /*
62  * Current position in C source (not updated when an included file is
63  * parsed).
64  */
65 pos_t csrc_pos = { "", 1, 0 };
66 
67 bool in_gcc_attribute;
68 bool in_system_header;
69 
70 /*
71  * Define a keyword that cannot be overridden by identifiers.
72  *
73  * Valid values for 'since' are 78, 90, 99, 11, 23.
74  *
75  * The C11 keywords are all taken from the reserved namespace.  They are added
76  * in C99 mode as well, to make the parse error messages more useful.  For
77  * example, if the keyword '_Generic' were not defined, it would be interpreted
78  * as an implicit function call, leading to a parse error.
79  *
80  * The C23 keywords are not made available in earlier modes, as they may
81  * conflict with user-defined identifiers.
82  */
83 #define kwdef(name, token, detail,	since, gcc, deco) \
84 	{ /* CONSTCOND */ \
85 		name, token, detail, \
86 		(since) == 90, \
87 		(since) == 99 || (since) == 11, \
88 		(since) == 23, \
89 		(gcc) > 0, \
90 		((deco) & 1) != 0, ((deco) & 2) != 0, ((deco) & 4) != 0, \
91 	}
92 #define kwdef_token(name, token,		since, gcc, deco) \
93 	kwdef(name, token, {false},		since, gcc, deco)
94 #define kwdef_sclass(name, sclass,		since, gcc, deco) \
95 	kwdef(name, T_SCLASS, .u.kw_scl = (sclass), since, gcc, deco)
96 #define kwdef_type(name, tspec,			since) \
97 	kwdef(name, T_TYPE, .u.kw_tspec = (tspec), since, 0, 1)
98 #define kwdef_tqual(name, tqual,		since, gcc, deco) \
99 	kwdef(name, T_QUAL, .u.kw_tqual = {.tqual = true}, since, gcc, deco)
100 #define kwdef_const(name, named_constant,	since, gcc, deco) \
101 	kwdef(name, T_NAMED_CONSTANT, \
102 	    .u.kw_named_constant = (named_constant), since, gcc, deco)
103 #define kwdef_keyword(name, token) \
104 	kwdef(name, token, {false},		78, 0, 1)
105 
106 /* During initialization, these keywords are written to the symbol table. */
107 static const struct keyword {
108 	const	char kw_name[20];
109 	int	kw_token;	/* token to be returned by yylex() */
110 	union {
111 		bool kw_dummy;
112 		scl_t kw_scl;		/* if kw_token is T_SCLASS */
113 		tspec_t kw_tspec;	/* if kw_token is T_TYPE or
114 					 * T_STRUCT_OR_UNION */
115 		type_qualifiers kw_tqual;	/* if kw_token is T_QUAL */
116 		function_specifier kw_fs;	/* if kw_token is
117 						 * T_FUNCTION_SPECIFIER */
118 		named_constant kw_named_constant;
119 	} u;
120 	bool	kw_added_in_c90:1;
121 	bool	kw_added_in_c99_or_c11:1;
122 	bool	kw_added_in_c23:1;
123 	bool	kw_gcc:1;	/* available in GCC mode */
124 	bool	kw_plain:1;	/* 'name' */
125 	bool	kw_leading:1;	/* '__name' */
126 	bool	kw_both:1;	/* '__name__' */
127 } keywords[] = {
128 	// TODO: _Alignas is not available in C99.
129 	kwdef_keyword(	"_Alignas",	T_ALIGNAS),
130 	// TODO: _Alignof is not available in C99.
131 	kwdef_keyword(	"_Alignof",	T_ALIGNOF),
132 	// TODO: alignof is not available in C99.
133 	kwdef_token(	"alignof",	T_ALIGNOF,		78,0,6),
134 	kwdef_token(	"asm",		T_ASM,			78,1,7),
135 	kwdef_token(	"_Atomic",	T_ATOMIC,		11,0,1),
136 	kwdef("__auto_type", T_TYPE, .u.kw_tspec = AUTO_TYPE,	99,1,1),
137 	kwdef_token(	"attribute",	T_ATTRIBUTE,		78,1,6),
138 	kwdef_sclass(	"auto",		AUTO,			78,0,1),
139 	kwdef_type(	"_Bool",	BOOL,			99),
140 	kwdef_type(	"bool",		BOOL,			23),
141 	kwdef_keyword(	"break",	T_BREAK),
142 	kwdef_token(	"__builtin_offsetof", T_BUILTIN_OFFSETOF, 78,1,1),
143 	kwdef_keyword(	"case",		T_CASE),
144 	kwdef_type(	"char",		CHAR,			78),
145 	kwdef_type(	"_Complex",	COMPLEX,		99),
146 	kwdef_tqual(	"const",	tq_const,		90,0,7),
147 	kwdef_keyword(	"continue",	T_CONTINUE),
148 	kwdef_keyword(	"default",	T_DEFAULT),
149 	kwdef_keyword(	"do",		T_DO),
150 	kwdef_type(	"double",	DOUBLE,			78),
151 	kwdef_keyword(	"else",		T_ELSE),
152 	// XXX: enum is not available in traditional C.
153 	kwdef_keyword(	"enum",		T_ENUM),
154 	kwdef_token(	"__extension__",T_EXTENSION,		78,1,1),
155 	kwdef_sclass(	"extern",	EXTERN,			78,0,1),
156 	kwdef_const(	"false",	NC_FALSE,		23,0,1),
157 	kwdef_type(	"float",	FLOAT,			78),
158 	kwdef_keyword(	"for",		T_FOR),
159 	kwdef_token(	"_Generic",	T_GENERIC,		11,0,1),
160 	kwdef_keyword(	"goto",		T_GOTO),
161 	kwdef_keyword(	"if",		T_IF),
162 	kwdef_token(	"__imag__",	T_IMAG,			78,1,1),
163 	kwdef("inline",	T_FUNCTION_SPECIFIER, .u.kw_fs = FS_INLINE, 99,0,7),
164 	kwdef_type(	"int",		INT,			78),
165 #ifdef INT128_SIZE
166 	kwdef_type(	"__int128_t",	INT128,			99),
167 #endif
168 	kwdef_type(	"long",		LONG,			78),
169 	kwdef("_Noreturn", T_FUNCTION_SPECIFIER, .u.kw_fs = FS_NORETURN, 11,0,1),
170 	kwdef_const(	"nullptr",	NC_NULLPTR,		23,0,1),
171 	// XXX: __packed is GCC-specific.
172 	kwdef_token(	"__packed",	T_PACKED,		78,0,1),
173 	kwdef_token(	"__real__",	T_REAL,			78,1,1),
174 	kwdef_sclass(	"register",	REG,			78,0,1),
175 	kwdef_tqual(	"restrict",	tq_restrict,		99,0,7),
176 	kwdef_keyword(	"return",	T_RETURN),
177 	kwdef_type(	"short",	SHORT,			78),
178 	kwdef(		"signed", T_TYPE, .u.kw_tspec = SIGNED,	90,0,3),
179 	kwdef_keyword(	"sizeof",	T_SIZEOF),
180 	kwdef_sclass(	"static",	STATIC,			78,0,1),
181 	// XXX: _Static_assert was added in C11.
182 	kwdef_keyword(	"_Static_assert",	T_STATIC_ASSERT),
183 	kwdef("struct",	T_STRUCT_OR_UNION, .u.kw_tspec = STRUCT, 78,0,1),
184 	kwdef_keyword(	"switch",	T_SWITCH),
185 	kwdef_token(	"__symbolrename",	T_SYMBOLRENAME,	78,0,1),
186 	kwdef_sclass(	"__thread",	THREAD_LOCAL,		78,1,1),
187 	kwdef_sclass(	"_Thread_local", THREAD_LOCAL,		11,0,1),
188 	kwdef_sclass(	"thread_local", THREAD_LOCAL,		23,0,1),
189 	kwdef_const(	"true",		NC_TRUE,		23,0,1),
190 	kwdef_sclass(	"typedef",	TYPEDEF,		78,0,1),
191 	kwdef_token(	"typeof",	T_TYPEOF,		78,1,7),
192 #ifdef INT128_SIZE
193 	kwdef_type(	"__uint128_t",	UINT128,		99),
194 #endif
195 	kwdef("union",	T_STRUCT_OR_UNION, .u.kw_tspec = UNION,	78,0,1),
196 	kwdef_type(	"unsigned",	UNSIGN,			78),
197 	// XXX: void is not available in traditional C.
198 	kwdef_type(	"void",		VOID,			78),
199 	kwdef_tqual(	"volatile",	tq_volatile,		90,0,7),
200 	kwdef_keyword(	"while",	T_WHILE),
201 #undef kwdef
202 #undef kwdef_token
203 #undef kwdef_sclass
204 #undef kwdef_type
205 #undef kwdef_tqual
206 #undef kwdef_keyword
207 };
208 
209 /*
210  * The symbol table containing all keywords, identifiers and labels. The hash
211  * entries are linked via sym_t.s_symtab_next.
212  */
213 static sym_t *symtab[503];
214 
215 /*
216  * The kind of the next expected symbol, to distinguish the namespaces of
217  * members, labels, type tags and other identifiers.
218  */
219 symbol_kind sym_kind;
220 
221 
222 static unsigned int
223 hash(const char *s)
224 {
225 	unsigned int v = 0;
226 	for (const char *p = s; *p != '\0'; p++) {
227 		v = (v << 4) + (unsigned char)*p;
228 		v ^= v >> 28;
229 	}
230 	return v % (sizeof(symtab) / sizeof(symtab[0]));
231 }
232 
233 static void
234 symtab_add(sym_t *sym)
235 {
236 	unsigned int h = hash(sym->s_name);
237 	if ((sym->s_symtab_next = symtab[h]) != NULL)
238 		symtab[h]->s_symtab_ref = &sym->s_symtab_next;
239 	sym->s_symtab_ref = &symtab[h];
240 	symtab[h] = sym;
241 }
242 
243 static sym_t *
244 symtab_search(const char *name)
245 {
246 
247 	unsigned int h = hash(name);
248 	for (sym_t *sym = symtab[h]; sym != NULL; sym = sym->s_symtab_next) {
249 		if (strcmp(sym->s_name, name) != 0)
250 			continue;
251 		if (sym->s_keyword != NULL ||
252 		    sym->s_kind == sym_kind ||
253 		    in_gcc_attribute)
254 			return sym;
255 	}
256 
257 	return NULL;
258 }
259 
260 static void
261 symtab_remove(sym_t *sym)
262 {
263 
264 	if ((*sym->s_symtab_ref = sym->s_symtab_next) != NULL)
265 		sym->s_symtab_next->s_symtab_ref = sym->s_symtab_ref;
266 	sym->s_symtab_next = NULL;
267 }
268 
269 static void
270 symtab_remove_locals(void)
271 {
272 
273 	for (size_t i = 0; i < sizeof(symtab) / sizeof(symtab[0]); i++) {
274 		for (sym_t *sym = symtab[i]; sym != NULL; ) {
275 			sym_t *next = sym->s_symtab_next;
276 			if (sym->s_block_level >= 1)
277 				symtab_remove(sym);
278 			sym = next;
279 		}
280 	}
281 }
282 
283 #ifdef DEBUG
284 static int
285 sym_by_name(const void *va, const void *vb)
286 {
287 	const sym_t *a = *(const sym_t *const *)va;
288 	const sym_t *b = *(const sym_t *const *)vb;
289 
290 	return strcmp(a->s_name, b->s_name);
291 }
292 
293 struct syms {
294 	const sym_t **items;
295 	size_t len;
296 	size_t cap;
297 };
298 
299 static void
300 syms_add(struct syms *syms, const sym_t *sym)
301 {
302 	if (syms->len >= syms->cap) {
303 		syms->cap *= 2;
304 		syms->items = xrealloc(syms->items,
305 		    syms->cap * sizeof(syms->items[0]));
306 	}
307 	syms->items[syms->len++] = sym;
308 }
309 
310 void
311 debug_symtab(void)
312 {
313 	struct syms syms = { xcalloc(64, sizeof(syms.items[0])), 0, 64 };
314 
315 	debug_enter();
316 	for (int level = -1;; level++) {
317 		bool more = false;
318 		size_t n = sizeof(symtab) / sizeof(symtab[0]);
319 
320 		syms.len = 0;
321 		for (size_t i = 0; i < n; i++) {
322 			for (sym_t *sym = symtab[i]; sym != NULL;) {
323 				if (sym->s_block_level == level &&
324 				    sym->s_keyword == NULL)
325 					syms_add(&syms, sym);
326 				if (sym->s_block_level > level)
327 					more = true;
328 				sym = sym->s_symtab_next;
329 			}
330 		}
331 
332 		if (syms.len > 0) {
333 			debug_step("symbol table level %d", level);
334 			debug_indent_inc();
335 			qsort(syms.items, syms.len, sizeof(syms.items[0]),
336 			    sym_by_name);
337 			for (size_t i = 0; i < syms.len; i++)
338 				debug_sym("", syms.items[i], "\n");
339 			debug_indent_dec();
340 
341 			lint_assert(level != -1);
342 		}
343 
344 		if (!more)
345 			break;
346 	}
347 	debug_leave();
348 
349 	free(syms.items);
350 }
351 #endif
352 
353 static void
354 register_keyword(const struct keyword *kw, bool leading, bool trailing)
355 {
356 
357 	const char *name;
358 	if (!leading && !trailing) {
359 		name = kw->kw_name;
360 	} else {
361 		char buf[256];
362 		(void)snprintf(buf, sizeof(buf), "%s%s%s",
363 		    leading ? "__" : "", kw->kw_name, trailing ? "__" : "");
364 		name = xstrdup(buf);
365 	}
366 
367 	sym_t *sym = block_zero_alloc(sizeof(*sym), "sym");
368 	sym->s_name = name;
369 	sym->s_keyword = kw;
370 	int tok = kw->kw_token;
371 	sym->u.s_keyword.sk_token = tok;
372 	if (tok == T_TYPE || tok == T_STRUCT_OR_UNION)
373 		sym->u.s_keyword.u.sk_tspec = kw->u.kw_tspec;
374 	if (tok == T_SCLASS)
375 		sym->s_scl = kw->u.kw_scl;
376 	if (tok == T_QUAL)
377 		sym->u.s_keyword.u.sk_type_qualifier = kw->u.kw_tqual;
378 	if (tok == T_FUNCTION_SPECIFIER)
379 		sym->u.s_keyword.u.function_specifier = kw->u.kw_fs;
380 	if (tok == T_NAMED_CONSTANT)
381 		sym->u.s_keyword.u.named_constant = kw->u.kw_named_constant;
382 
383 	symtab_add(sym);
384 }
385 
386 static bool
387 is_keyword_known(const struct keyword *kw)
388 {
389 
390 	if (kw->kw_added_in_c23 && !allow_c23)
391 		return false;
392 	if ((kw->kw_added_in_c90 || kw->kw_added_in_c99_or_c11) && !allow_c90)
393 		return false;
394 
395 	/*
396 	 * In the 1990s, GCC defined several keywords that were later
397 	 * incorporated into C99, therefore in GCC mode, all C99 keywords are
398 	 * made available.  The C11 keywords are made available as well, but
399 	 * there are so few that they don't matter practically.
400 	 */
401 	if (allow_gcc)
402 		return true;
403 	if (kw->kw_gcc)
404 		return false;
405 
406 	if (kw->kw_added_in_c99_or_c11 && !allow_c99)
407 		return false;
408 	return true;
409 }
410 
411 /* Write all keywords to the symbol table. */
412 void
413 init_lex(void)
414 {
415 
416 	size_t n = sizeof(keywords) / sizeof(keywords[0]);
417 	for (size_t i = 0; i < n; i++) {
418 		const struct keyword *kw = keywords + i;
419 		if (!is_keyword_known(kw))
420 			continue;
421 		if (kw->kw_plain)
422 			register_keyword(kw, false, false);
423 		if (kw->kw_leading)
424 			register_keyword(kw, true, false);
425 		if (kw->kw_both)
426 			register_keyword(kw, true, true);
427 	}
428 }
429 
430 /*
431  * When scanning the remainder of a long token (see lex_input), read a byte
432  * and return it as an unsigned char or as EOF.
433  *
434  * Increment the line counts if necessary.
435  */
436 static int
437 read_byte(void)
438 {
439 	int c = lex_input();
440 
441 	if (c == '\n')
442 		lex_next_line();
443 	return c == '\0' ? EOF : c;	/* lex returns 0 on EOF. */
444 }
445 
446 static int
447 lex_keyword(sym_t *sym)
448 {
449 	int tok = sym->u.s_keyword.sk_token;
450 
451 	if (tok == T_SCLASS)
452 		yylval.y_scl = sym->s_scl;
453 	if (tok == T_TYPE || tok == T_STRUCT_OR_UNION)
454 		yylval.y_tspec = sym->u.s_keyword.u.sk_tspec;
455 	if (tok == T_QUAL)
456 		yylval.y_type_qualifiers =
457 		    sym->u.s_keyword.u.sk_type_qualifier;
458 	if (tok == T_FUNCTION_SPECIFIER)
459 		yylval.y_function_specifier =
460 		    sym->u.s_keyword.u.function_specifier;
461 	if (tok == T_NAMED_CONSTANT)
462 		yylval.y_named_constant = sym->u.s_keyword.u.named_constant;
463 	return tok;
464 }
465 
466 /*
467  * Look up the definition of a name in the symbol table. This symbol must
468  * either be a keyword or a symbol of the type required by sym_kind (label,
469  * member, tag, ...).
470  */
471 extern int
472 lex_name(const char *text, size_t len)
473 {
474 
475 	sym_t *sym = symtab_search(text);
476 	if (sym != NULL && sym->s_keyword != NULL)
477 		return lex_keyword(sym);
478 
479 	sbuf_t *sb = xmalloc(sizeof(*sb));
480 	sb->sb_len = len;
481 	sb->sb_sym = sym;
482 	yylval.y_name = sb;
483 
484 	if (sym != NULL) {
485 		lint_assert(block_level >= sym->s_block_level);
486 		sb->sb_name = sym->s_name;
487 		return sym->s_scl == TYPEDEF ? T_TYPENAME : T_NAME;
488 	}
489 
490 	char *name = block_zero_alloc(len + 1, "string");
491 	(void)memcpy(name, text, len + 1);
492 	sb->sb_name = name;
493 	return T_NAME;
494 }
495 
496 static tspec_t
497 integer_constant_type_signed(unsigned ls, uint64_t ui, int base, bool warned)
498 {
499 	if (ls == 0 && ui <= TARG_INT_MAX)
500 		return INT;
501 	if (ls == 0 && ui <= TARG_UINT_MAX && base != 10 && allow_c90)
502 		return UINT;
503 	if (ls == 0 && ui <= TARG_LONG_MAX)
504 		return LONG;
505 
506 	if (ls <= 1 && ui <= TARG_LONG_MAX)
507 		return LONG;
508 	if (ls <= 1 && ui <= TARG_ULONG_MAX && base != 10)
509 		return allow_c90 ? ULONG : LONG;
510 	if (ls <= 1 && !allow_c99) {
511 		if (!warned)
512 			/* integer constant out of range */
513 			warning(252);
514 		return allow_c90 ? ULONG : LONG;
515 	}
516 
517 	if (ui <= TARG_LLONG_MAX)
518 		return LLONG;
519 	if (ui <= TARG_ULLONG_MAX && base != 10)
520 		return allow_c90 ? ULLONG : LLONG;
521 	if (!warned)
522 		/* integer constant out of range */
523 		warning(252);
524 	return allow_c90 ? ULLONG : LLONG;
525 }
526 
527 static tspec_t
528 integer_constant_type_unsigned(unsigned l, uint64_t ui, bool warned)
529 {
530 	if (l == 0 && ui <= TARG_UINT_MAX)
531 		return UINT;
532 
533 	if (l <= 1 && ui <= TARG_ULONG_MAX)
534 		return ULONG;
535 	if (l <= 1 && !allow_c99) {
536 		if (!warned)
537 			/* integer constant out of range */
538 			warning(252);
539 		return ULONG;
540 	}
541 
542 	if (ui <= TARG_ULLONG_MAX)
543 		return ULLONG;
544 	if (!warned)
545 		/* integer constant out of range */
546 		warning(252);
547 	return ULLONG;
548 }
549 
550 int
551 lex_integer_constant(const char *text, size_t len, int base)
552 {
553 	const char *cp = text;
554 
555 	/* skip 0[xX] or 0[bB] */
556 	if (base == 16 || base == 2) {
557 		cp += 2;
558 		len -= 2;
559 	}
560 
561 	/* read suffixes */
562 	unsigned l_suffix = 0, u_suffix = 0;
563 	for (;; len--) {
564 		char c = cp[len - 1];
565 		if (c == 'l' || c == 'L')
566 			l_suffix++;
567 		else if (c == 'u' || c == 'U')
568 			u_suffix++;
569 		else
570 			break;
571 	}
572 	if (l_suffix > 2 || u_suffix > 1) {
573 		/* malformed integer constant */
574 		warning(251);
575 		if (l_suffix > 2)
576 			l_suffix = 2;
577 		if (u_suffix > 1)
578 			u_suffix = 1;
579 	}
580 	if (!allow_c90 && u_suffix > 0)
581 		/* suffix 'U' is illegal in traditional C */
582 		warning(97);
583 
584 	bool warned = false;
585 	errno = 0;
586 	char *eptr;
587 	uint64_t ui = (uint64_t)strtoull(cp, &eptr, base);
588 	lint_assert(eptr == cp + len);
589 	if (errno != 0) {
590 		/* integer constant out of range */
591 		warning(252);
592 		warned = true;
593 	}
594 
595 	if (base == 8 && len > 1)
596 		/* octal number '%.*s' */
597 		query_message(8, (int)len, cp);
598 
599 	bool unsigned_since_c90 = allow_trad && allow_c90 && u_suffix == 0
600 	    && ui > TARG_INT_MAX
601 	    && ((l_suffix == 0 && base != 10 && ui <= TARG_UINT_MAX)
602 		|| (l_suffix <= 1 && ui > TARG_LONG_MAX));
603 
604 	tspec_t t = u_suffix > 0
605 	    ? integer_constant_type_unsigned(l_suffix, ui, warned)
606 	    : integer_constant_type_signed(l_suffix, ui, base, warned);
607 	ui = (uint64_t)convert_integer((int64_t)ui, t, size_in_bits(t));
608 
609 	yylval.y_val = xcalloc(1, sizeof(*yylval.y_val));
610 	yylval.y_val->v_tspec = t;
611 	yylval.y_val->v_unsigned_since_c90 = unsigned_since_c90;
612 	yylval.y_val->u.integer = (int64_t)ui;
613 
614 	return T_CON;
615 }
616 
617 /* Extend or truncate si to match t.  If t is signed, sign-extend. */
618 int64_t
619 convert_integer(int64_t si, tspec_t t, unsigned int bits)
620 {
621 
622 	uint64_t vbits = value_bits(bits);
623 	uint64_t ui = (uint64_t)si;
624 	return t == PTR || is_uinteger(t) || ((ui & bit(bits - 1)) == 0)
625 	    ? (int64_t)(ui & vbits)
626 	    : (int64_t)(ui | ~vbits);
627 }
628 
629 int
630 lex_floating_constant(const char *text, size_t len)
631 {
632 	const char *cp = text;
633 
634 	bool imaginary = cp[len - 1] == 'i';
635 	if (imaginary)
636 		len--;
637 
638 	char c = cp[len - 1];
639 	tspec_t t;
640 	if (c == 'f' || c == 'F') {
641 		t = imaginary ? FCOMPLEX : FLOAT;
642 		len--;
643 	} else if (c == 'l' || c == 'L') {
644 		t = imaginary ? LCOMPLEX : LDOUBLE;
645 		len--;
646 	} else
647 		t = imaginary ? DCOMPLEX : DOUBLE;
648 
649 	if (!allow_c90 && t != DOUBLE)
650 		/* suffixes 'F' and 'L' are illegal in traditional C */
651 		warning(98);
652 
653 	errno = 0;
654 	char *eptr;
655 	long double ld = strtold(cp, &eptr);
656 	lint_assert(eptr == cp + len);
657 	if (errno != 0)
658 		/* floating-point constant out of range */
659 		warning(248);
660 	else if (t == FLOAT) {
661 		ld = (float)ld;
662 		if (isfinite(ld) == 0) {
663 			/* floating-point constant out of range */
664 			warning(248);
665 			ld = ld > 0 ? FLT_MAX : -FLT_MAX;
666 		}
667 	} else if (t == DOUBLE
668 	    || /* CONSTCOND */ LDOUBLE_SIZE == DOUBLE_SIZE) {
669 		ld = (double)ld;
670 		if (isfinite(ld) == 0) {
671 			/* floating-point constant out of range */
672 			warning(248);
673 			ld = ld > 0 ? DBL_MAX : -DBL_MAX;
674 		}
675 	}
676 
677 	yylval.y_val = xcalloc(1, sizeof(*yylval.y_val));
678 	yylval.y_val->v_tspec = t;
679 	yylval.y_val->u.floating = ld;
680 
681 	return T_CON;
682 }
683 
684 int
685 lex_operator(int t, op_t o)
686 {
687 
688 	yylval.y_op = o;
689 	return t;
690 }
691 
692 static buffer
693 read_quoted(bool *complete, char delim, bool wide)
694 {
695 	buffer buf;
696 	buf_init(&buf);
697 	if (wide)
698 		buf_add_char(&buf, 'L');
699 	buf_add_char(&buf, delim);
700 
701 	for (;;) {
702 		int c = read_byte();
703 		if (c <= 0)
704 			break;
705 		buf_add_char(&buf, (char)c);
706 		if (c == '\n')
707 			break;
708 		if (c == delim) {
709 			*complete = true;
710 			return buf;
711 		}
712 		if (c == '\\') {
713 			c = read_byte();
714 			buf_add_char(&buf, (char)(c <= 0 ? ' ' : c));
715 			if (c <= 0)
716 				break;
717 		}
718 	}
719 	*complete = false;
720 	buf_add_char(&buf, delim);
721 	return buf;
722 }
723 
724 /*
725  * Analyze the lexical representation of the next character in the string
726  * literal list. At the end, only update the position information.
727  */
728 bool
729 quoted_next(const buffer *lit, quoted_iterator *it)
730 {
731 	const char *s = lit->data;
732 
733 	*it = (quoted_iterator){ .start = it->end };
734 
735 	char delim = s[s[0] == 'L' ? 1 : 0];
736 
737 	bool in_the_middle = it->start > 0;
738 	if (!in_the_middle) {
739 		it->start = s[0] == 'L' ? 2 : 1;
740 		it->end = it->start;
741 	}
742 
743 	while (s[it->start] == delim) {
744 		if (it->start + 1 == lit->len) {
745 			it->end = it->start;
746 			return false;
747 		}
748 		it->next_literal = in_the_middle;
749 		it->start += 2;
750 	}
751 	it->end = it->start;
752 
753 again:
754 	switch (s[it->end]) {
755 	case '\\':
756 		it->end++;
757 		goto backslash;
758 	case '\n':
759 		it->unescaped_newline = true;
760 		return false;
761 	default:
762 		it->value = (unsigned char)s[it->end++];
763 		return true;
764 	}
765 
766 backslash:
767 	it->escaped = true;
768 	if ('0' <= s[it->end] && s[it->end] <= '7')
769 		goto octal_escape;
770 	switch (s[it->end++]) {
771 	case '\n':
772 		goto again;
773 	case 'a':
774 		it->named_escape = true;
775 		it->value = '\a';
776 		it->invalid_escape = !allow_c90;
777 		return true;
778 	case 'b':
779 		it->named_escape = true;
780 		it->value = '\b';
781 		return true;
782 	case 'e':
783 		it->named_escape = true;
784 		it->value = '\033';
785 		it->invalid_escape = !allow_gcc;
786 		return true;
787 	case 'f':
788 		it->named_escape = true;
789 		it->value = '\f';
790 		return true;
791 	case 'n':
792 		it->named_escape = true;
793 		it->value = '\n';
794 		return true;
795 	case 'r':
796 		it->named_escape = true;
797 		it->value = '\r';
798 		return true;
799 	case 't':
800 		it->named_escape = true;
801 		it->value = '\t';
802 		return true;
803 	case 'v':
804 		it->named_escape = true;
805 		it->value = '\v';
806 		it->invalid_escape = !allow_c90;
807 		return true;
808 	case 'x':
809 		goto hex_escape;
810 	case '"':
811 		it->literal_escape = true;
812 		it->value = '"';
813 		it->invalid_escape = !allow_c90 && delim == '\'';
814 		return true;
815 	case '?':
816 		it->literal_escape = true;
817 		it->value = '?';
818 		it->invalid_escape = !allow_c90;
819 		return true;
820 	default:
821 		it->invalid_escape = true;
822 		/* FALLTHROUGH */
823 	case '\'':
824 	case '\\':
825 		it->literal_escape = true;
826 		it->value = (unsigned char)s[it->end - 1];
827 		return true;
828 	}
829 
830 octal_escape:
831 	it->octal_digits++;
832 	it->value = s[it->end++] - '0';
833 	if ('0' <= s[it->end] && s[it->end] <= '7') {
834 		it->octal_digits++;
835 		it->value = 8 * it->value + (s[it->end++] - '0');
836 		if ('0' <= s[it->end] && s[it->end] <= '7') {
837 			it->octal_digits++;
838 			it->value = 8 * it->value + (s[it->end++] - '0');
839 			it->overflow = it->value > TARG_UCHAR_MAX
840 			    && s[0] != 'L';
841 		}
842 	}
843 	return true;
844 
845 hex_escape:
846 	for (;;) {
847 		char ch = s[it->end];
848 		unsigned digit_value;
849 		if ('0' <= ch && ch <= '9')
850 			digit_value = ch - '0';
851 		else if ('A' <= ch && ch <= 'F')
852 			digit_value = 10 + (ch - 'A');
853 		else if ('a' <= ch && ch <= 'f')
854 			digit_value = 10 + (ch - 'a');
855 		else
856 			break;
857 
858 		it->end++;
859 		it->value = 16 * it->value + digit_value;
860 		uint64_t limit = s[0] == 'L' ? TARG_UINT_MAX : TARG_UCHAR_MAX;
861 		if (it->value > limit)
862 			it->overflow = true;
863 		if (it->hex_digits < 3)
864 			it->hex_digits++;
865 	}
866 	it->missing_hex_digits = it->hex_digits == 0;
867 	return true;
868 }
869 
870 static void
871 check_quoted(const buffer *buf, bool complete, char delim)
872 {
873 	quoted_iterator it = { .end = 0 }, prev = it;
874 	for (; quoted_next(buf, &it); prev = it) {
875 		if (it.missing_hex_digits)
876 			/* no hex digits follow \x */
877 			error(74);
878 		if (it.hex_digits > 0 && !allow_c90)
879 			/* \x undefined in traditional C */
880 			warning(82);
881 		else if (!it.invalid_escape)
882 			;
883 		else if (it.value == '8' || it.value == '9')
884 			/* bad octal digit '%c' */
885 			warning(77, (int)it.value);
886 		else if (it.literal_escape && it.value == '?')
887 			/* \? undefined in traditional C */
888 			warning(263);
889 		else if (it.literal_escape && it.value == '"')
890 			/* \" inside character constants undefined in ... */
891 			warning(262);
892 		else if (it.named_escape && it.value == '\a')
893 			/* \a undefined in traditional C */
894 			warning(81);
895 		else if (it.named_escape && it.value == '\v')
896 			/* \v undefined in traditional C */
897 			warning(264);
898 		else {
899 			unsigned char ch = buf->data[it.end - 1];
900 			if (ch_isprint(ch))
901 				/* dubious escape \%c */
902 				warning(79, ch);
903 			else
904 				/* dubious escape \%o */
905 				warning(80, ch);
906 		}
907 		if (it.overflow && it.hex_digits > 0)
908 			/* overflow in hex escape */
909 			warning(75);
910 		if (it.overflow && it.octal_digits > 0)
911 			/* character escape does not fit in character */
912 			warning(76);
913 		if (it.value < ' ' && !it.escaped && complete)
914 			/* invisible character U+%04X in %s */
915 			query_message(17, (unsigned)it.value, delim == '"'
916 			    ? "string literal" : "character constant");
917 		if (prev.octal_digits > 0 && prev.octal_digits < 3
918 		    && !it.escaped && it.value >= '8' && it.value <= '9')
919 			/* short octal escape '%.*s' followed by digit '%c' */
920 			warning(356, (int)(prev.end - prev.start),
921 			    buf->data + prev.start, buf->data[it.start]);
922 	}
923 	if (it.unescaped_newline)
924 		/* newline in string or char constant */
925 		error(254);
926 	if (!complete && delim == '"')
927 		/* unterminated string constant */
928 		error(258);
929 	if (!complete && delim == '\'')
930 		/* unterminated character constant */
931 		error(253);
932 }
933 
934 static buffer
935 lex_quoted(char delim, bool wide)
936 {
937 	bool complete;
938 	buffer buf = read_quoted(&complete, delim, wide);
939 	check_quoted(&buf, complete, delim);
940 	return buf;
941 }
942 
943 /* Called if lex found a leading "'". */
944 int
945 lex_character_constant(void)
946 {
947 	buffer buf = lex_quoted('\'', false);
948 
949 	size_t n = 0;
950 	uint64_t val = 0;
951 	quoted_iterator it = { .end = 0 };
952 	while (quoted_next(&buf, &it)) {
953 		val = (val << CHAR_SIZE) + it.value;
954 		n++;
955 	}
956 	if (n > sizeof(int) || (n > 1 && (pflag || hflag))) {
957 		/*
958 		 * XXX: ^^ should rather be sizeof(TARG_INT). Luckily,
959 		 * sizeof(int) is the same on all supported platforms.
960 		 */
961 		/* too many characters in character constant */
962 		error(71);
963 	} else if (n > 1)
964 		/* multi-character character constant */
965 		warning(294);
966 	else if (n == 0 && !it.unescaped_newline)
967 		/* empty character constant */
968 		error(73);
969 
970 	int64_t cval = n == 1
971 	    ? convert_integer((int64_t)val, CHAR, CHAR_SIZE)
972 	    : (int64_t)val;
973 
974 	yylval.y_val = xcalloc(1, sizeof(*yylval.y_val));
975 	yylval.y_val->v_tspec = INT;
976 	yylval.y_val->v_char_constant = true;
977 	yylval.y_val->u.integer = cval;
978 
979 	return T_CON;
980 }
981 
982 /* Called if lex found a leading "L'". */
983 int
984 lex_wide_character_constant(void)
985 {
986 	buffer buf = lex_quoted('\'', true);
987 
988 	static char wbuf[MB_LEN_MAX + 1];
989 	size_t n = 0, nmax = MB_CUR_MAX;
990 
991 	quoted_iterator it = { .end = 0 };
992 	while (quoted_next(&buf, &it)) {
993 		if (n < nmax)
994 			wbuf[n] = (char)it.value;
995 		n++;
996 	}
997 
998 	wchar_t wc = 0;
999 	if (n == 0)
1000 		/* empty character constant */
1001 		error(73);
1002 	else if (n > nmax) {
1003 		n = nmax;
1004 		/* too many characters in character constant */
1005 		error(71);
1006 	} else {
1007 		wbuf[n] = '\0';
1008 		(void)mbtowc(NULL, NULL, 0);
1009 		if (mbtowc(&wc, wbuf, nmax) < 0)
1010 			/* invalid multibyte character */
1011 			error(291);
1012 	}
1013 
1014 	yylval.y_val = xcalloc(1, sizeof(*yylval.y_val));
1015 	yylval.y_val->v_tspec = WCHAR_TSPEC;
1016 	yylval.y_val->v_char_constant = true;
1017 	yylval.y_val->u.integer = wc;
1018 
1019 	return T_CON;
1020 }
1021 
1022 /* See https://gcc.gnu.org/onlinedocs/cpp/Preprocessor-Output.html */
1023 static void
1024 parse_line_directive_flags(const char *p,
1025 			   bool *is_begin, bool *is_end, bool *is_system)
1026 {
1027 
1028 	*is_begin = false;
1029 	*is_end = false;
1030 	*is_system = false;
1031 
1032 	while (*p != '\0') {
1033 		while (ch_isspace(*p))
1034 			p++;
1035 
1036 		const char *word = p;
1037 		while (*p != '\0' && !ch_isspace(*p))
1038 			p++;
1039 		size_t len = (size_t)(p - word);
1040 
1041 		if (len == 1 && word[0] == '1')
1042 			*is_begin = true;
1043 		if (len == 1 && word[0] == '2')
1044 			*is_end = true;
1045 		if (len == 1 && word[0] == '3')
1046 			*is_system = true;
1047 		/* Flag '4' is only interesting for C++. */
1048 	}
1049 }
1050 
1051 /*
1052  * The first directive of the preprocessed translation unit provides the name
1053  * of the C source file as specified at the command line.
1054  */
1055 static void
1056 set_csrc_pos(void)
1057 {
1058 	static bool done;
1059 
1060 	if (done)
1061 		return;
1062 	done = true;
1063 	csrc_pos.p_file = curr_pos.p_file;
1064 	outsrc(transform_filename(curr_pos.p_file, strlen(curr_pos.p_file)));
1065 }
1066 
1067 /* # lineno ["filename" [GCC-flag...]]  */
1068 static void
1069 set_location(const char *p)
1070 {
1071 	char *end;
1072 	long ln = strtol(--p, &end, 10);
1073 	if (end == p)
1074 		goto error;
1075 	p = end;
1076 
1077 	if (*p != ' ' && *p != '\0')
1078 		goto error;
1079 	while (*p == ' ')
1080 		p++;
1081 
1082 	if (*p != '\0') {
1083 		if (*p != '"')
1084 			goto error;
1085 		const char *fn = ++p;
1086 		while (*p != '"' && *p != '\0')
1087 			p++;
1088 		if (*p != '"')
1089 			goto error;
1090 		size_t fn_len = p++ - fn;
1091 		if (fn_len > PATH_MAX)
1092 			goto error;
1093 		if (fn_len == 0) {
1094 			fn = "{standard input}";
1095 			fn_len = strlen(fn);
1096 		}
1097 		curr_pos.p_file = record_filename(fn, fn_len);
1098 		set_csrc_pos();
1099 
1100 		bool is_begin, is_end, is_system;
1101 		parse_line_directive_flags(p, &is_begin, &is_end, &is_system);
1102 		update_location(curr_pos.p_file, (int)ln, is_begin, is_end);
1103 		in_system_header = is_system;
1104 	}
1105 	curr_pos.p_line = (int)ln - 1;
1106 	curr_pos.p_uniq = 0;
1107 	if (curr_pos.p_file == csrc_pos.p_file) {
1108 		csrc_pos.p_line = (int)ln - 1;
1109 		csrc_pos.p_uniq = 0;
1110 	}
1111 	return;
1112 
1113 error:
1114 	/* undefined or invalid '#' directive */
1115 	warning(255);
1116 }
1117 
1118 static void
1119 check_stmt_macro(const char *text)
1120 {
1121 	const char *p = text;
1122 	while (*p == ' ')
1123 		p++;
1124 
1125 	const char *name_start = p;
1126 	while (ch_isalnum(*p) || *p == '_')
1127 		p++;
1128 	const char *name_end = p;
1129 
1130 	if (*p == '(') {
1131 		while (*p != '\0' && *p != ')')
1132 			p++;
1133 		if (*p == ')')
1134 			p++;
1135 	}
1136 
1137 	while (*p == ' ')
1138 		p++;
1139 
1140 	if (strncmp(p, "do", 2) == 0 && !ch_isalnum(p[2]))
1141 		/* do-while macro '%.*s' ends with semicolon */
1142 		warning(385, (int)(name_end - name_start), name_start);
1143 }
1144 
1145 // Between lex_pp_begin and lex_pp_end, the current preprocessing line,
1146 // with comments and whitespace converted to a single space.
1147 static buffer pp_line;
1148 
1149 void
1150 lex_pp_begin(void)
1151 {
1152 	if (pp_line.data == NULL)
1153 		buf_init(&pp_line);
1154 	debug_step("%s", __func__);
1155 	lint_assert(pp_line.len == 0);
1156 }
1157 
1158 void
1159 lex_pp_identifier(const char *text)
1160 {
1161 	debug_step("%s '%s'", __func__, text);
1162 	buf_add(&pp_line, text);
1163 }
1164 
1165 void
1166 lex_pp_number(const char *text)
1167 {
1168 	debug_step("%s '%s'", __func__, text);
1169 	buf_add(&pp_line, text);
1170 }
1171 
1172 void
1173 lex_pp_character_constant(void)
1174 {
1175 	buffer buf = lex_quoted('\'', false);
1176 	debug_step("%s '%s'", __func__, buf.data);
1177 	buf_add(&pp_line, buf.data);
1178 	free(buf.data);
1179 }
1180 
1181 void
1182 lex_pp_string_literal(void)
1183 {
1184 	buffer buf = lex_quoted('"', false);
1185 	debug_step("%s '%s'", __func__, buf.data);
1186 	buf_add(&pp_line, buf.data);
1187 	free(buf.data);
1188 }
1189 
1190 void
1191 lex_pp_punctuator(const char *text)
1192 {
1193 	debug_step("%s '%s'", __func__, text);
1194 	buf_add(&pp_line, text);
1195 }
1196 
1197 void
1198 lex_pp_comment(void)
1199 {
1200 	int lc = -1, c;
1201 
1202 	for (;;) {
1203 		if ((c = read_byte()) == EOF) {
1204 			/* unterminated comment */
1205 			error(256);
1206 			return;
1207 		}
1208 		if (lc == '*' && c == '/')
1209 			break;
1210 		lc = c;
1211 	}
1212 
1213 	buf_add_char(&pp_line, ' ');
1214 }
1215 
1216 void
1217 lex_pp_whitespace(void)
1218 {
1219 	buf_add_char(&pp_line, ' ');
1220 }
1221 
1222 void
1223 lex_pp_end(void)
1224 {
1225 	const char *text = pp_line.data;
1226 	size_t len = pp_line.len;
1227 	while (len > 0 && text[len - 1] == ' ')
1228 		len--;
1229 	debug_step("%s '%.*s'", __func__, (int)len, text);
1230 
1231 	const char *p = text;
1232 	while (*p == ' ')
1233 		p++;
1234 
1235 	if (ch_isdigit(*p))
1236 		set_location(p);
1237 	else if (strncmp(p, "pragma ", 7) == 0)
1238 		goto done;
1239 	else if (strncmp(p, "define ", 7) == 0) {
1240 		 if (text[len - 1] == ';')
1241 			check_stmt_macro(p + 7);
1242 	} else if (strncmp(p, "undef ", 6) == 0)
1243 		goto done;
1244 	else
1245 		/* undefined or invalid '#' directive */
1246 		warning(255);
1247 
1248 done:
1249 	pp_line.len = 0;
1250 	pp_line.data[0] = '\0';
1251 }
1252 
1253 /* Handle lint comments such as ARGSUSED. */
1254 void
1255 lex_comment(void)
1256 {
1257 	int c;
1258 	static const struct {
1259 		const	char name[18];
1260 		bool	arg;
1261 		lint_comment comment;
1262 	} keywtab[] = {
1263 		{ "ARGSUSED",		true,	LC_ARGSUSED	},
1264 		{ "BITFIELDTYPE",	false,	LC_BITFIELDTYPE	},
1265 		{ "CONSTCOND",		false,	LC_CONSTCOND	},
1266 		{ "CONSTANTCOND",	false,	LC_CONSTCOND	},
1267 		{ "CONSTANTCONDITION",	false,	LC_CONSTCOND	},
1268 		{ "FALLTHRU",		false,	LC_FALLTHROUGH	},
1269 		{ "FALLTHROUGH",	false,	LC_FALLTHROUGH	},
1270 		{ "FALL THROUGH",	false,	LC_FALLTHROUGH	},
1271 		{ "fallthrough",	false,	LC_FALLTHROUGH	},
1272 		{ "LINTLIBRARY",	false,	LC_LINTLIBRARY	},
1273 		{ "LINTED",		true,	LC_LINTED	},
1274 		{ "LONGLONG",		false,	LC_LONGLONG	},
1275 		{ "NOSTRICT",		true,	LC_LINTED	},
1276 		{ "NOTREACHED",		false,	LC_NOTREACHED	},
1277 		{ "PRINTFLIKE",		true,	LC_PRINTFLIKE	},
1278 		{ "PROTOLIB",		true,	LC_PROTOLIB	},
1279 		{ "SCANFLIKE",		true,	LC_SCANFLIKE	},
1280 		{ "VARARGS",		true,	LC_VARARGS	},
1281 	};
1282 	char keywd[32];
1283 
1284 	bool seen_end_of_comment = false;
1285 
1286 	while (c = read_byte(), isspace(c) != 0)
1287 		continue;
1288 
1289 	/* Read the potential keyword to keywd */
1290 	size_t l = 0;
1291 	while (c != EOF && l < sizeof(keywd) - 1 &&
1292 	    (isalpha(c) != 0 || isspace(c) != 0)) {
1293 		if (islower(c) != 0 && l > 0 && ch_isupper(keywd[0]))
1294 			break;
1295 		keywd[l++] = (char)c;
1296 		c = read_byte();
1297 	}
1298 	while (l > 0 && ch_isspace(keywd[l - 1]))
1299 		l--;
1300 	keywd[l] = '\0';
1301 
1302 	/* look for the keyword */
1303 	size_t i;
1304 	for (i = 0; i < sizeof(keywtab) / sizeof(keywtab[0]); i++)
1305 		if (strcmp(keywtab[i].name, keywd) == 0)
1306 			goto found_keyword;
1307 	goto skip_rest;
1308 
1309 found_keyword:
1310 	while (isspace(c) != 0)
1311 		c = read_byte();
1312 
1313 	/* read the argument, if the keyword accepts one and there is one */
1314 	char arg[32];
1315 	l = 0;
1316 	if (keywtab[i].arg) {
1317 		while (isdigit(c) != 0 && l < sizeof(arg) - 1) {
1318 			arg[l++] = (char)c;
1319 			c = read_byte();
1320 		}
1321 	}
1322 	arg[l] = '\0';
1323 	int a = l != 0 ? atoi(arg) : -1;
1324 
1325 	while (isspace(c) != 0)
1326 		c = read_byte();
1327 
1328 	seen_end_of_comment = c == '*' && (c = read_byte()) == '/';
1329 	if (!seen_end_of_comment && keywtab[i].comment != LC_LINTED)
1330 		/* extra characters in lint comment */
1331 		warning(257);
1332 
1333 	handle_lint_comment(keywtab[i].comment, a);
1334 
1335 skip_rest:
1336 	while (!seen_end_of_comment) {
1337 		int lc = c;
1338 		if ((c = read_byte()) == EOF) {
1339 			/* unterminated comment */
1340 			error(256);
1341 			break;
1342 		}
1343 		if (lc == '*' && c == '/')
1344 			seen_end_of_comment = true;
1345 	}
1346 }
1347 
1348 void
1349 lex_slash_slash_comment(void)
1350 {
1351 
1352 	if (!allow_c99 && !allow_gcc)
1353 		/* %s does not support '//' comments */
1354 		gnuism(312, allow_c90 ? "C90" : "traditional C");
1355 
1356 	for (int c; c = read_byte(), c != EOF && c != '\n';)
1357 		continue;
1358 }
1359 
1360 void
1361 reset_suppressions(void)
1362 {
1363 
1364 	lwarn = LWARN_ALL;
1365 	suppress_longlong = false;
1366 	suppress_constcond = false;
1367 }
1368 
1369 int
1370 lex_string(void)
1371 {
1372 	buffer *buf = xmalloc(sizeof(*buf));
1373 	*buf = lex_quoted('"', false);
1374 	yylval.y_string = buf;
1375 	return T_STRING;
1376 }
1377 
1378 static size_t
1379 wide_length(const buffer *buf)
1380 {
1381 
1382 	(void)mblen(NULL, 0);
1383 	size_t len = 0, i = 0;
1384 	while (i < buf->len) {
1385 		int n = mblen(buf->data + i, MB_CUR_MAX);
1386 		if (n == -1) {
1387 			/* invalid multibyte character */
1388 			error(291);
1389 			break;
1390 		}
1391 		i += n > 1 ? n : 1;
1392 		len++;
1393 	}
1394 	return len;
1395 }
1396 
1397 int
1398 lex_wide_string(void)
1399 {
1400 	buffer buf = lex_quoted('"', true);
1401 
1402 	buffer str;
1403 	buf_init(&str);
1404 	quoted_iterator it = { .end = 0 };
1405 	while (quoted_next(&buf, &it))
1406 		buf_add_char(&str, (char)it.value);
1407 
1408 	free(buf.data);
1409 
1410 	buffer *len_buf = xcalloc(1, sizeof(*len_buf));
1411 	len_buf->len = wide_length(&str);
1412 	yylval.y_string = len_buf;
1413 	return T_STRING;
1414 }
1415 
1416 void
1417 lex_next_line(void)
1418 {
1419 	curr_pos.p_line++;
1420 	curr_pos.p_uniq = 0;
1421 	debug_skip_indent();
1422 	debug_printf("parsing %s:%d\n", curr_pos.p_file, curr_pos.p_line);
1423 	if (curr_pos.p_file == csrc_pos.p_file) {
1424 		csrc_pos.p_line++;
1425 		csrc_pos.p_uniq = 0;
1426 	}
1427 }
1428 
1429 void
1430 lex_unknown_character(int c)
1431 {
1432 
1433 	/* unknown character \%o */
1434 	error(250, c);
1435 }
1436 
1437 /*
1438  * The scanner does not create new symbol table entries for symbols it cannot
1439  * find in the symbol table. This is to avoid putting undeclared symbols into
1440  * the symbol table if a syntax error occurs.
1441  *
1442  * getsym is called as soon as it is probably ok to put the symbol in the
1443  * symbol table. It is still possible that symbols are put in the symbol
1444  * table that are not completely declared due to syntax errors. To avoid too
1445  * many problems in this case, symbols get type 'int' in getsym.
1446  *
1447  * XXX calls to getsym should be delayed until declare_1_* is called.
1448  */
1449 sym_t *
1450 getsym(sbuf_t *sb)
1451 {
1452 
1453 	sym_t *sym = sb->sb_sym;
1454 
1455 	/*
1456 	 * During member declaration it is possible that name() looked for
1457 	 * symbols of type SK_VCFT, although it should have looked for symbols
1458 	 * of type SK_TAG. Same can happen for labels. Both cases are
1459 	 * compensated here.
1460 	 */
1461 	if (sym_kind == SK_MEMBER || sym_kind == SK_LABEL) {
1462 		if (sym == NULL || sym->s_kind == SK_VCFT)
1463 			sym = symtab_search(sb->sb_name);
1464 	}
1465 
1466 	if (sym != NULL) {
1467 		lint_assert(sym->s_kind == sym_kind);
1468 		set_sym_kind(SK_VCFT);
1469 		free(sb);
1470 		return sym;
1471 	}
1472 
1473 	/* create a new symbol table entry */
1474 
1475 	decl_level *dl;
1476 	if (sym_kind == SK_LABEL) {
1477 		sym = level_zero_alloc(1, sizeof(*sym), "sym");
1478 		char *s = level_zero_alloc(1, sb->sb_len + 1, "string");
1479 		(void)memcpy(s, sb->sb_name, sb->sb_len + 1);
1480 		sym->s_name = s;
1481 		sym->s_block_level = 1;
1482 		dl = dcs;
1483 		while (dl->d_enclosing != NULL &&
1484 		    dl->d_enclosing->d_enclosing != NULL)
1485 			dl = dl->d_enclosing;
1486 		lint_assert(dl->d_kind == DLK_AUTO);
1487 	} else {
1488 		sym = block_zero_alloc(sizeof(*sym), "sym");
1489 		sym->s_name = sb->sb_name;
1490 		sym->s_block_level = block_level;
1491 		dl = dcs;
1492 	}
1493 
1494 	sym->s_def_pos = unique_curr_pos();
1495 	if ((sym->s_kind = sym_kind) != SK_LABEL)
1496 		sym->s_type = gettyp(INT);
1497 
1498 	set_sym_kind(SK_VCFT);
1499 
1500 	if (!in_gcc_attribute) {
1501 		debug_printf("%s: symtab_add ", __func__);
1502 		debug_sym("", sym, "\n");
1503 		symtab_add(sym);
1504 
1505 		*dl->d_last_dlsym = sym;
1506 		dl->d_last_dlsym = &sym->s_level_next;
1507 	}
1508 
1509 	free(sb);
1510 	return sym;
1511 }
1512 
1513 /*
1514  * Construct a temporary symbol. The symbol name starts with a digit to avoid
1515  * name clashes with other identifiers.
1516  */
1517 sym_t *
1518 mktempsym(type_t *tp)
1519 {
1520 	static unsigned n = 0;
1521 	char *s = level_zero_alloc((size_t)block_level, 64, "string");
1522 	sym_t *sym = block_zero_alloc(sizeof(*sym), "sym");
1523 	scl_t scl;
1524 
1525 	(void)snprintf(s, 64, "%.8u_tmp", n++);
1526 
1527 	scl = dcs->d_scl;
1528 	if (scl == NO_SCL)
1529 		scl = block_level > 0 ? AUTO : EXTERN;
1530 
1531 	sym->s_name = s;
1532 	sym->s_type = tp;
1533 	sym->s_block_level = block_level;
1534 	sym->s_scl = scl;
1535 	sym->s_kind = SK_VCFT;
1536 	sym->s_used = true;
1537 	sym->s_set = true;
1538 
1539 	symtab_add(sym);
1540 
1541 	*dcs->d_last_dlsym = sym;
1542 	dcs->d_last_dlsym = &sym->s_level_next;
1543 
1544 	return sym;
1545 }
1546 
1547 void
1548 symtab_remove_forever(sym_t *sym)
1549 {
1550 
1551 	debug_step("%s '%s' %s '%s'", __func__,
1552 	    sym->s_name, symbol_kind_name(sym->s_kind),
1553 	    type_name(sym->s_type));
1554 	symtab_remove(sym);
1555 
1556 	/* avoid that the symbol will later be put back to the symbol table */
1557 	sym->s_block_level = -1;
1558 }
1559 
1560 /*
1561  * Remove all symbols from the symbol table that have the same level as the
1562  * given symbol.
1563  */
1564 void
1565 symtab_remove_level(sym_t *syms)
1566 {
1567 
1568 	if (syms != NULL)
1569 		debug_step("%s %d", __func__, syms->s_block_level);
1570 
1571 	/* Note the use of s_level_next instead of s_symtab_next. */
1572 	for (sym_t *sym = syms; sym != NULL; sym = sym->s_level_next) {
1573 		if (sym->s_block_level != -1) {
1574 			debug_step("%s '%s' %s '%s' %d", __func__,
1575 			    sym->s_name, symbol_kind_name(sym->s_kind),
1576 			    type_name(sym->s_type), sym->s_block_level);
1577 			symtab_remove(sym);
1578 			sym->s_symtab_ref = NULL;
1579 		}
1580 	}
1581 }
1582 
1583 /* Put a symbol into the symbol table. */
1584 void
1585 inssym(int level, sym_t *sym)
1586 {
1587 
1588 	debug_step("%s '%s' %s '%s' %d", __func__,
1589 	    sym->s_name, symbol_kind_name(sym->s_kind),
1590 	    type_name(sym->s_type), level);
1591 	sym->s_block_level = level;
1592 	symtab_add(sym);
1593 
1594 	const sym_t *next = sym->s_symtab_next;
1595 	if (next != NULL)
1596 		lint_assert(sym->s_block_level >= next->s_block_level);
1597 }
1598 
1599 /* Called at level 0 after syntax errors. */
1600 void
1601 clean_up_after_error(void)
1602 {
1603 
1604 	symtab_remove_locals();
1605 
1606 	while (mem_block_level > 0)
1607 		level_free_all(mem_block_level--);
1608 }
1609 
1610 /* Create a new symbol with the same name as an existing symbol. */
1611 sym_t *
1612 pushdown(const sym_t *sym)
1613 {
1614 
1615 	debug_step("pushdown '%s' %s '%s'",
1616 	    sym->s_name, symbol_kind_name(sym->s_kind),
1617 	    type_name(sym->s_type));
1618 
1619 	sym_t *nsym = block_zero_alloc(sizeof(*nsym), "sym");
1620 	lint_assert(sym->s_block_level <= block_level);
1621 	nsym->s_name = sym->s_name;
1622 	nsym->s_def_pos = unique_curr_pos();
1623 	nsym->s_kind = sym->s_kind;
1624 	nsym->s_block_level = block_level;
1625 
1626 	symtab_add(nsym);
1627 
1628 	*dcs->d_last_dlsym = nsym;
1629 	dcs->d_last_dlsym = &nsym->s_level_next;
1630 
1631 	return nsym;
1632 }
1633 
1634 static void
1635 fill_token(int tk, const char *text, token *tok)
1636 {
1637 	switch (tk) {
1638 	case T_NAME:
1639 	case T_TYPENAME:
1640 		tok->kind = TK_IDENTIFIER;
1641 		tok->u.identifier = xstrdup(yylval.y_name->sb_name);
1642 		break;
1643 	case T_CON:
1644 		tok->kind = TK_CONSTANT;
1645 		tok->u.constant = *yylval.y_val;
1646 		break;
1647 	case T_NAMED_CONSTANT:
1648 		tok->kind = TK_IDENTIFIER;
1649 		tok->u.identifier = xstrdup(text);
1650 		break;
1651 	case T_STRING:;
1652 		tok->kind = TK_STRING_LITERALS;
1653 		tok->u.string_literals.len = yylval.y_string->len;
1654 		tok->u.string_literals.cap = yylval.y_string->cap;
1655 		tok->u.string_literals.data = xstrdup(yylval.y_string->data);
1656 		break;
1657 	default:
1658 		tok->kind = TK_PUNCTUATOR;
1659 		tok->u.punctuator = xstrdup(text);
1660 	}
1661 }
1662 
1663 static void
1664 seq_reserve(balanced_token_sequence *seq)
1665 {
1666 	if (seq->len >= seq->cap) {
1667 		seq->cap = 16 + 2 * seq->cap;
1668 		const balanced_token *old_tokens = seq->tokens;
1669 		balanced_token *new_tokens = block_zero_alloc(
1670 		    seq->cap * sizeof(*seq->tokens), "balanced_token[]");
1671 		if (seq->len > 0)
1672 			memcpy(new_tokens, old_tokens,
1673 			    seq->len * sizeof(*seq->tokens));
1674 		seq->tokens = new_tokens;
1675 	}
1676 }
1677 
1678 static balanced_token_sequence
1679 read_balanced(int opening)
1680 {
1681 	int closing = opening == T_LPAREN ? T_RPAREN
1682 	    : opening == T_LBRACK ? T_RBRACK : T_RBRACE;
1683 	balanced_token_sequence seq = { NULL, 0, 0 };
1684 
1685 	int tok;
1686 	while (tok = yylex(), tok > 0 && tok != closing) {
1687 		seq_reserve(&seq);
1688 		if (tok == T_LPAREN || tok == T_LBRACK || tok == T_LBRACE) {
1689 			seq.tokens[seq.len].kind = tok == T_LPAREN ? '('
1690 			    : tok == T_LBRACK ? '[' : '{';
1691 			seq.tokens[seq.len].u.tokens = read_balanced(tok);
1692 		} else {
1693 			fill_token(tok, yytext, &seq.tokens[seq.len].u.token);
1694 			freeyyv(&yylval, tok);
1695 		}
1696 		seq.len++;
1697 	}
1698 	return seq;
1699 }
1700 
1701 balanced_token_sequence
1702 lex_balanced(void)
1703 {
1704 	return read_balanced(T_LPAREN);
1705 }
1706 
1707 /*
1708  * Free any dynamically allocated memory referenced by
1709  * the value stack or yylval.
1710  * The type of information in yylval is described by tok.
1711  */
1712 void
1713 freeyyv(void *sp, int tok)
1714 {
1715 	if (tok == T_NAME || tok == T_TYPENAME) {
1716 		sbuf_t *sb = *(sbuf_t **)sp;
1717 		free(sb);
1718 	} else if (tok == T_CON) {
1719 		val_t *val = *(val_t **)sp;
1720 		free(val);
1721 	} else if (tok == T_STRING) {
1722 		buffer *str = *(buffer **)sp;
1723 		free(str->data);
1724 		free(str);
1725 	}
1726 }
1727