aboutsummaryrefslogtreecommitdiff
path: root/gdb/ada-lex.l
blob: 3a3647b589460d2e310890c9cd3c1c96979e2f8a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
/* FLEX lexer for Ada expressions, for GDB. -*- c++ -*-
   Copyright (C) 1994-2022 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/*----------------------------------------------------------------------*/

/* The converted version of this file is to be included in ada-exp.y, */
/* the Ada parser for gdb.  The function yylex obtains characters from */
/* the global pointer lexptr.  It returns a syntactic category for */
/* each successive token and places a semantic value into yylval */
/* (ada-lval), defined by the parser.   */

DIG	[0-9]
NUM10	({DIG}({DIG}|_)*)
HEXDIG	[0-9a-f]
NUM16	({HEXDIG}({HEXDIG}|_)*)
OCTDIG	[0-7]
LETTER	[a-z_]
ID	({LETTER}({LETTER}|{DIG}|[\x80-\xff])*|"<"{LETTER}({LETTER}|{DIG})*">")
WHITE	[ \t\n]
TICK	("'"{WHITE}*)
GRAPHIC [a-z0-9 #&'()*+,-./:;<>=_|!$%?@\[\]\\^`{}~]
OPER    ([-+*/=<>&]|"<="|">="|"**"|"/="|"and"|"or"|"xor"|"not"|"mod"|"rem"|"abs")

EXP	(e[+-]{NUM10})
POSEXP  (e"+"?{NUM10})

/* This must agree with COMPLETION_CHAR below.  See the comment there
   for the explanation.  */
COMPLETE "\001"
NOT_COMPLETE [^\001]

%{

#include "diagnostics.h"

/* Some old versions of flex generate code that uses the "register" keyword,
   which clang warns about.  This was observed for example with flex 2.5.35,
   as shipped with macOS 10.12.  The same happens with flex 2.5.37 and g++ 11
   which defaults to ISO C++17, that does not allow register storage class
   specifiers.  */
DIAGNOSTIC_PUSH
DIAGNOSTIC_IGNORE_DEPRECATED_REGISTER

#define NUMERAL_WIDTH 256
#define LONGEST_SIGN ((ULONGEST) 1 << (sizeof(LONGEST) * HOST_CHAR_BIT - 1))

/* Temporary staging for numeric literals.  */
static char numbuf[NUMERAL_WIDTH];
 static void canonicalizeNumeral (char *s1, const char *);
static struct stoken processString (const char*, int);
static int processInt (struct parser_state *, const char *, const char *,
		       const char *);
static int processReal (struct parser_state *, const char *);
static struct stoken processId (const char *, int);
static int processAttribute (const char *);
static int find_dot_all (const char *);
static void rewind_to_char (int);

#undef YY_DECL
#define YY_DECL static int yylex ( void )

/* Flex generates a static function "input" which is not used.
   Defining YY_NO_INPUT comments it out.  */
#define YY_NO_INPUT

/* When completing, we'll return a special character at the end of the
   input, to signal the completion position to the lexer.  This is
   done because flex does not have a generally useful way to detect
   EOF in a pattern.  This variable records whether the special
   character has been emitted.  */
static bool returned_complete = false;

/* The character we use to represent the completion point.  */
#define COMPLETE_CHAR '\001'

#undef YY_INPUT
#define YY_INPUT(BUF, RESULT, MAX_SIZE)					\
  if ( *pstate->lexptr == '\000' )					\
    {									\
      if (pstate->parse_completion && !returned_complete)		\
	{								\
	  returned_complete = true;					\
	  *(BUF) = COMPLETE_CHAR;					\
	  (RESULT) = 1;							\
	}								\
      else								\
	(RESULT) = YY_NULL;						\
    }									\
  else									\
    {									\
      *(BUF) = *pstate->lexptr == COMPLETE_CHAR ? ' ' : *pstate->lexptr; \
      (RESULT) = 1;							\
      pstate->lexptr += 1;						\
    }

/* Depth of parentheses.  */
static int paren_depth;

%}

%option case-insensitive interactive nodefault noyywrap

%s BEFORE_QUAL_QUOTE

%%

{WHITE}		 { }

"--".*		 { yyterminate(); }

{NUM10}{POSEXP}  {
		   canonicalizeNumeral (numbuf, yytext);
		   char *e_ptr = strrchr (numbuf, 'e');
		   *e_ptr = '\0';
		   return processInt (pstate, nullptr, numbuf, e_ptr + 1);
		 }

{NUM10}          {
		   canonicalizeNumeral (numbuf, yytext);
		   return processInt (pstate, NULL, numbuf, NULL);
		 }

{NUM10}"#"{HEXDIG}({HEXDIG}|_)*"#"{POSEXP} {
		   canonicalizeNumeral (numbuf, yytext);
		   char *e_ptr = strrchr (numbuf, 'e');
		   *e_ptr = '\0';
		   return processInt (pstate, numbuf,
				      strchr (numbuf, '#') + 1,
				      e_ptr + 1);
		 }

	/* The "llf" is a gdb extension to allow a floating-point
	   constant to be written in some other base.  The
	   floating-point number is formed by reinterpreting the
	   bytes, allowing direct control over the bits.  */
{NUM10}(l{0,2}f)?"#"{HEXDIG}({HEXDIG}|_)*"#" {
		   canonicalizeNumeral (numbuf, yytext);
		   return processInt (pstate, numbuf, strchr (numbuf, '#') + 1,
				      NULL);
		 }

"0x"{HEXDIG}+	{
		  canonicalizeNumeral (numbuf, yytext+2);
		  return processInt (pstate, "16#", numbuf, NULL);
		}


{NUM10}"."{NUM10}{EXP} {
		   canonicalizeNumeral (numbuf, yytext);
		   return processReal (pstate, numbuf);
		}

{NUM10}"."{NUM10} {
		   canonicalizeNumeral (numbuf, yytext);
		   return processReal (pstate, numbuf);
		}

{NUM10}"#"{NUM16}"."{NUM16}"#"{EXP} {
                   error (_("Based real literals not implemented yet."));
		}

{NUM10}"#"{NUM16}"."{NUM16}"#" {
                   error (_("Based real literals not implemented yet."));
		}

<INITIAL>"'"({GRAPHIC}|\")"'" {
		   yylval.typed_val.val = yytext[1];
		   yylval.typed_val.type = type_for_char (pstate, yytext[1]);
		   return CHARLIT;
		}

<INITIAL>"'[\""{HEXDIG}{2,}"\"]'"   {
                   ULONGEST v = strtoulst (yytext+3, nullptr, 16);
		   yylval.typed_val.val = v;
                   yylval.typed_val.type = type_for_char (pstate, v);
		   return CHARLIT;
		}

	/* Note that we don't handle bracket sequences of more than 2
	   digits here.  Currently there's no support for wide or
	   wide-wide strings.  */
\"({GRAPHIC}|"[\""({HEXDIG}{2,}|\")"\"]")*\"   {
	           yylval.sval = processString (yytext+1, yyleng-2);
		   return STRING;
		}

\"              {
                   error (_("ill-formed or non-terminated string literal"));
		}


if		{
                  rewind_to_char ('i');
		  return 0;
		}

task            {
                  rewind_to_char ('t');
		  return 0;
		}

thread{WHITE}+{DIG} {
                  /* This keyword signals the end of the expression and
                     will be processed separately.  */
                  rewind_to_char ('t');
		  return 0;
		}

	/* ADA KEYWORDS */

abs		{ return ABS; }
and		{ return _AND_; }
else		{ return ELSE; }
in		{ return IN; }
mod		{ return MOD; }
new		{ return NEW; }
not		{ return NOT; }
null		{ return NULL_PTR; }
or		{ return OR; }
others          { return OTHERS; }
rem		{ return REM; }
then		{ return THEN; }
xor		{ return XOR; }

	/* BOOLEAN "KEYWORDS" */

 /* True and False are not keywords in Ada, but rather enumeration constants.
    However, the boolean type is no longer represented as an enum, so True
    and False are no longer defined in symbol tables.  We compromise by
    making them keywords (when bare). */

true		{ return TRUEKEYWORD; }
false		{ return FALSEKEYWORD; }

        /* ATTRIBUTES */

{TICK}([a-z][a-z_]*)?{COMPLETE}? { BEGIN INITIAL; return processAttribute (yytext); }

	/* PUNCTUATION */

"=>"		{ return ARROW; }
".."		{ return DOTDOT; }
"**"		{ return STARSTAR; }
":="		{ return ASSIGN; }
"/="		{ return NOTEQUAL; }
"<="		{ return LEQ; }
">="		{ return GEQ; }

<BEFORE_QUAL_QUOTE>"'"/{NOT_COMPLETE} { BEGIN INITIAL; return '\''; }

[-&*+{}@/:<>=|;\[\]] { return yytext[0]; }

","		{ if (paren_depth == 0 && pstate->comma_terminates)
		    {
		      rewind_to_char (',');
		      return 0;
		    }
		  else
		    return ',';
		}

"("		{ paren_depth += 1; return '('; }
")"		{ if (paren_depth == 0)
		    {
		      rewind_to_char (')');
		      return 0;
		    }
		  else
 		    {
		      paren_depth -= 1;
		      return ')';
		    }
		}

"."{WHITE}*{ID}{COMPLETE}? {
	 	  yylval.sval = processId (yytext+1, yyleng-1);
		  if (yytext[yyleng - 1] == COMPLETE_CHAR)
		    return DOT_COMPLETE;
	          return DOT_ID;
		}

"."{WHITE}*{COMPLETE} {
		  yylval.sval.ptr = "";
		  yylval.sval.length = 0;
		  return DOT_COMPLETE;
		}

{ID}({WHITE}*"."{WHITE}*({ID}|\"{OPER}\"))*(" "*"'"|{COMPLETE})?  {
                  int all_posn = find_dot_all (yytext);

                  if (all_posn == -1 && yytext[yyleng-1] == '\'')
		    {
		      BEGIN BEFORE_QUAL_QUOTE;
		      yyless (yyleng-1);
		    }
                  else if (all_posn >= 0)
		    yyless (all_posn);
		  bool is_completion = yytext[yyleng - 1] == COMPLETE_CHAR;
                  yylval.sval = processId (yytext, yyleng);
                  return is_completion ? NAME_COMPLETE : NAME;
               }


	/* GDB EXPRESSION CONSTRUCTS  */

"'"[^']+"'"{WHITE}*:: {
                  yyless (yyleng - 2);
		  yylval.sval = processId (yytext, yyleng);
		  return NAME;
		}

"::"            { return COLONCOLON; }

	/* REGISTERS AND GDB CONVENIENCE VARIABLES */

"$"({LETTER}|{DIG}|"$")*  {
		  yylval.sval.ptr = yytext;
		  yylval.sval.length = yyleng;
		  return DOLLAR_VARIABLE;
		}

	/* CATCH-ALL ERROR CASE */

.		{ error (_("Invalid character '%s' in expression."), yytext); }
%%

#include <ctype.h>
/* Initialize the lexer for processing new expression. */

static void
lexer_init (FILE *inp)
{
  BEGIN INITIAL;
  paren_depth = 0;
  returned_complete = false;
  yyrestart (inp);
}


/* Copy S2 to S1, removing all underscores, and downcasing all letters.  */

static void
canonicalizeNumeral (char *s1, const char *s2)
{
  for (; *s2 != '\000'; s2 += 1)
    {
      if (*s2 != '_')
	{
	  *s1 = tolower(*s2);
	  s1 += 1;
	}
    }
  s1[0] = '\000';
}

/* Interprets the prefix of NUM that consists of digits of the given BASE
   as an integer of that BASE, with the string EXP as an exponent.
   Puts value in yylval, and returns INT, if the string is valid.  Causes
   an error if the number is improperly formated.   BASE, if NULL, defaults
   to "10", and EXP to "1".  The EXP does not contain a leading 'e' or 'E'.
 */

static int
processInt (struct parser_state *par_state, const char *base0,
	    const char *num0, const char *exp0)
{
  long exp;
  int base;
  /* For the based literal with an "f" prefix, we'll return a
     floating-point number.  This counts the the number of "l"s seen,
     to decide the width of the floating-point number to return.  -1
     means no "f".  */
  int floating_point_l_count = -1;

  if (base0 == NULL)
    base = 10;
  else
    {
      char *end_of_base;
      base = strtol (base0, &end_of_base, 10);
      if (base < 2 || base > 16)
	error (_("Invalid base: %d."), base);
      while (*end_of_base == 'l')
	{
	  ++floating_point_l_count;
	  ++end_of_base;
	}
      /* This assertion is ensured by the pattern.  */
      gdb_assert (floating_point_l_count == -1 || *end_of_base == 'f');
      if (*end_of_base == 'f')
	{
	  ++end_of_base;
	  ++floating_point_l_count;
	}
      /* This assertion is ensured by the pattern.  */
      gdb_assert (*end_of_base == '#');
    }

  if (exp0 == NULL)
    exp = 0;
  else
    exp = strtol(exp0, (char **) NULL, 10);

  gdb_mpz result;
  while (isxdigit (*num0))
    {
      int dig = fromhex (*num0);
      if (dig >= base)
	error (_("Invalid digit `%c' in based literal"), *num0);
      mpz_mul_ui (result.val, result.val, base);
      mpz_add_ui (result.val, result.val, dig);
      ++num0;
    }

  while (exp > 0)
    {
      mpz_mul_ui (result.val, result.val, base);
      exp -= 1;
    }

  if (floating_point_l_count > -1)
    {
      struct type *fp_type;
      if (floating_point_l_count == 0)
	fp_type = language_lookup_primitive_type (par_state->language (),
						  par_state->gdbarch (),
						  "float");
      else if (floating_point_l_count == 1)
	fp_type = language_lookup_primitive_type (par_state->language (),
						  par_state->gdbarch (),
						  "long_float");
      else
	{
	  /* This assertion is ensured by the pattern.  */
	  gdb_assert (floating_point_l_count == 2);
	  fp_type = language_lookup_primitive_type (par_state->language (),
						    par_state->gdbarch (),
						    "long_long_float");
	}

      yylval.typed_val_float.type = fp_type;
      result.write (gdb::make_array_view (yylval.typed_val_float.val,
					  fp_type->length ()),
		    type_byte_order (fp_type),
		    true);

      return FLOAT;
    }

  gdb_mpz maxval (ULONGEST_MAX);
  if (mpz_cmp (result.val, maxval.val) > 0)
    error (_("Integer literal out of range"));

  int int_bits = gdbarch_int_bit (par_state->gdbarch ());
  int long_bits = gdbarch_long_bit (par_state->gdbarch ());
  int long_long_bits = gdbarch_long_long_bit (par_state->gdbarch ());

  ULONGEST value = result.as_integer<ULONGEST> ();
  if (fits_in_type (1, value, int_bits, true))
    yylval.typed_val.type = type_int (par_state);
  else if (fits_in_type (1, value, long_bits, true))
    yylval.typed_val.type = type_long (par_state);
  else if (fits_in_type (1, value, long_bits, false))
    {
      /* We have a number representable as an unsigned integer quantity.
         For consistency with the C treatment, we will treat it as an
	 anonymous modular (unsigned) quantity.  Alas, the types are such
	 that we need to store .val as a signed quantity.  Sorry
         for the mess, but C doesn't officially guarantee that a simple
         assignment does the trick (no, it doesn't; read the reference manual).
       */
      yylval.typed_val.type
	= builtin_type (par_state->gdbarch ())->builtin_unsigned_long;
      if (value & LONGEST_SIGN)
	yylval.typed_val.val =
	  (LONGEST) (value & ~LONGEST_SIGN)
	  - (LONGEST_SIGN>>1) - (LONGEST_SIGN>>1);
      else
	yylval.typed_val.val = (LONGEST) value;
      return INT;
    }
  else if (fits_in_type (1, value, long_long_bits, true))
    yylval.typed_val.type = type_long_long (par_state);
  else if (fits_in_type (1, value, long_long_bits, false))
    {
      yylval.typed_val.type
	= builtin_type (par_state->gdbarch ())->builtin_unsigned_long_long;
      /* See unsigned long case above.  */
      if (value & LONGEST_SIGN)
	yylval.typed_val.val =
	  (LONGEST) (value & ~LONGEST_SIGN)
	  - (LONGEST_SIGN>>1) - (LONGEST_SIGN>>1);
      else
	yylval.typed_val.val = (LONGEST) value;
      return INT;
    }
  else
    error (_("Integer literal out of range"));

  yylval.typed_val.val = value;
  return INT;
}

static int
processReal (struct parser_state *par_state, const char *num0)
{
  yylval.typed_val_float.type = type_long_double (par_state);

  bool parsed = parse_float (num0, strlen (num0),
			     yylval.typed_val_float.type,
			     yylval.typed_val_float.val);
  gdb_assert (parsed);
  return FLOAT;
}


/* Store a canonicalized version of NAME0[0..LEN-1] in yylval.ssym.  The
   resulting string is valid until the next call to ada_parse.  If
   NAME0 contains the substring "___", it is assumed to be already
   encoded and the resulting name is equal to it.  Similarly, if the name
   starts with '<', it is copied verbatim.  Otherwise, it differs
   from NAME0 in that:
    + Characters between '...' are transfered verbatim to yylval.ssym.
    + Trailing "'" characters in quoted sequences are removed (a leading quote is
      preserved to indicate that the name is not to be GNAT-encoded).
    + Unquoted whitespace is removed.
    + Unquoted alphabetic characters are mapped to lower case.
   Result is returned as a struct stoken, but for convenience, the string
   is also null-terminated.  Result string valid until the next call of
   ada_parse.
 */
static struct stoken
processId (const char *name0, int len)
{
  char *name = (char *) obstack_alloc (&temp_parse_space, len + 11);
  int i0, i;
  struct stoken result;

  result.ptr = name;
  while (len > 0 && isspace (name0[len-1]))
    len -= 1;

  if (name0[0] == '<' || strstr (name0, "___") != NULL)
    {
      strncpy (name, name0, len);
      name[len] = '\000';
      result.length = len;
      return result;
    }

  bool in_quotes = false;
  i = i0 = 0;
  while (i0 < len)
    {
      if (name0[i0] == COMPLETE_CHAR)
	{
	  /* Just ignore.  */
	  ++i0;
	}
      else if (in_quotes)
	name[i++] = name0[i0++];
      else if (isalnum (name0[i0]))
	{
	  name[i] = tolower (name0[i0]);
	  i += 1; i0 += 1;
	}
      else if (isspace (name0[i0]))
	i0 += 1;
      else if (name0[i0] == '\'')
	{
	  /* Copy the starting quote, but not the ending quote.  */
	  if (!in_quotes)
	    name[i++] = name0[i0++];
	  in_quotes = !in_quotes;
	}
      else
	name[i++] = name0[i0++];
    }
  name[i] = '\000';

  result.length = i;
  return result;
}

/* Return TEXT[0..LEN-1], a string literal without surrounding quotes,
   with special hex character notations replaced with characters. 
   Result valid until the next call to ada_parse.  */

static struct stoken
processString (const char *text, int len)
{
  const char *p;
  char *q;
  const char *lim = text + len;
  struct stoken result;

  q = (char *) obstack_alloc (&temp_parse_space, len);
  result.ptr = q;
  p = text;
  while (p < lim)
    {
      if (p[0] == '[' && p[1] == '"' && p+2 < lim)
         {
           if (p[2] == '"')  /* "...["""]... */
             {
               *q = '"';
	       p += 4;
	     }
           else
	     {
	       const char *end;
	       ULONGEST chr = strtoulst (p + 2, &end, 16);
	       if (chr > 0xff)
		 error (_("wide strings are not yet supported"));
	       *q = (char) chr;
	       p = end + 1;
	     }
         }
       else
         *q = *p;
       q += 1;
       p += 1;
     }
  result.length = q - result.ptr;
  return result;
}

/* Returns the position within STR of the '.' in a
   '.{WHITE}*all' component of a dotted name, or -1 if there is none.
   Note: we actually don't need this routine, since 'all' can never be an
   Ada identifier.  Thus, looking up foo.all or foo.all.x as a name
   must fail, and will eventually be interpreted as (foo).all or
   (foo).all.x.  However, this does avoid an extraneous lookup. */

static int
find_dot_all (const char *str)
{
  int i;

  for (i = 0; str[i] != '\000'; i++)
    if (str[i] == '.')
      {
	int i0 = i;

	do
	  i += 1;
	while (isspace (str[i]));

	if (strncasecmp (str + i, "all", 3) == 0
	    && !isalnum (str[i + 3]) && str[i + 3] != '_')
	  return i0;
      }
  return -1;
}

/* Returns non-zero iff string SUBSEQ matches a subsequence of STR, ignoring
   case.  */

static int
subseqMatch (const char *subseq, const char *str)
{
  if (subseq[0] == '\0')
    return 1;
  else if (str[0] == '\0')
    return 0;
  else if (tolower (subseq[0]) == tolower (str[0]))
    return subseqMatch (subseq+1, str+1) || subseqMatch (subseq, str+1);
  else
    return subseqMatch (subseq, str+1);
}


static struct { const char *name; int code; }
attributes[] = {
  { "address", TICK_ADDRESS },
  { "unchecked_access", TICK_ACCESS },
  { "unrestricted_access", TICK_ACCESS },
  { "access", TICK_ACCESS },
  { "first", TICK_FIRST },
  { "last", TICK_LAST },
  { "length", TICK_LENGTH },
  { "max", TICK_MAX },
  { "min", TICK_MIN },
  { "modulus", TICK_MODULUS },
  { "pos", TICK_POS },
  { "range", TICK_RANGE },
  { "size", TICK_SIZE },
  { "tag", TICK_TAG },
  { "val", TICK_VAL },
};

/* Return the syntactic code corresponding to the attribute name or
   abbreviation STR.  */

static int
processAttribute (const char *str)
{
  gdb_assert (*str == '\'');
  ++str;
  while (isspace (*str))
    ++str;

  int len = strlen (str);
  if (len > 0 && str[len - 1] == COMPLETE_CHAR)
    {
      /* This is enforced by YY_INPUT.  */
      gdb_assert (pstate->parse_completion);
      yylval.sval.ptr = obstack_strndup (&temp_parse_space, str, len - 1);
      yylval.sval.length = len - 1;
      return TICK_COMPLETE;
    }

  for (const auto &item : attributes)
    if (strcasecmp (str, item.name) == 0)
      return item.code;

  gdb::optional<int> found;
  for (const auto &item : attributes)
    if (subseqMatch (str, item.name))
      {
	if (!found.has_value ())
	  found = item.code;
	else
	  error (_("ambiguous attribute name: `%s'"), str);
      }
  if (!found.has_value ())
    error (_("unrecognized attribute: `%s'"), str);

  return *found;
}

bool
ada_tick_completer::complete (struct expression *exp,
			      completion_tracker &tracker)
{
  completion_list output;
  for (const auto &item : attributes)
    {
      if (strncasecmp (item.name, m_name.c_str (), m_name.length ()) == 0)
	output.emplace_back (xstrdup (item.name));
    }
  tracker.add_completions (std::move (output));
  return true;
}

/* Back up lexptr by yyleng and then to the rightmost occurrence of
   character CH, case-folded (there must be one).  WARNING: since
   lexptr points to the next input character that Flex has not yet
   transferred to its internal buffer, the use of this function
   depends on the assumption that Flex calls YY_INPUT only when it is
   logically necessary to do so (thus, there is no reading ahead
   farther than needed to identify the next token.)  */

static void
rewind_to_char (int ch)
{
  pstate->lexptr -= yyleng;
  while (toupper (*pstate->lexptr) != toupper (ch))
    pstate->lexptr -= 1;
  yyrestart (NULL);
}

/* Dummy definition to suppress warnings about unused static definitions. */
typedef void (*dummy_function) ();
dummy_function ada_flex_use[] = 
{ 
  (dummy_function) yyunput
};

DIAGNOSTIC_POP