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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [libcpp/] [expr.c] - Blame information for rev 304

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1 270 jeremybenn
/* Parse C expressions for cpplib.
2
   Copyright (C) 1987, 1992, 1994, 1995, 1997, 1998, 1999, 2000, 2001,
3
   2002, 2004, 2008, 2009, 2010 Free Software Foundation.
4
   Contributed by Per Bothner, 1994.
5
 
6
This program is free software; you can redistribute it and/or modify it
7
under the terms of the GNU General Public License as published by the
8
Free Software Foundation; either version 3, or (at your option) any
9
later version.
10
 
11
This program is distributed in the hope that it will be useful,
12
but WITHOUT ANY WARRANTY; without even the implied warranty of
13
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14
GNU General Public License for more details.
15
 
16
You should have received a copy of the GNU General Public License
17
along with this program; see the file COPYING3.  If not see
18
<http://www.gnu.org/licenses/>.  */
19
 
20
#include "config.h"
21
#include "system.h"
22
#include "cpplib.h"
23
#include "internal.h"
24
 
25
#define PART_PRECISION (sizeof (cpp_num_part) * CHAR_BIT)
26
#define HALF_MASK (~(cpp_num_part) 0 >> (PART_PRECISION / 2))
27
#define LOW_PART(num_part) (num_part & HALF_MASK)
28
#define HIGH_PART(num_part) (num_part >> (PART_PRECISION / 2))
29
 
30
struct op
31
{
32
  const cpp_token *token;       /* The token forming op (for diagnostics).  */
33
  cpp_num value;                /* The value logically "right" of op.  */
34
  source_location loc;          /* The location of this value.         */
35
  enum cpp_ttype op;
36
};
37
 
38
/* Some simple utility routines on double integers.  */
39
#define num_zerop(num) ((num.low | num.high) == 0)
40
#define num_eq(num1, num2) (num1.low == num2.low && num1.high == num2.high)
41
static bool num_positive (cpp_num, size_t);
42
static bool num_greater_eq (cpp_num, cpp_num, size_t);
43
static cpp_num num_trim (cpp_num, size_t);
44
static cpp_num num_part_mul (cpp_num_part, cpp_num_part);
45
 
46
static cpp_num num_unary_op (cpp_reader *, cpp_num, enum cpp_ttype);
47
static cpp_num num_binary_op (cpp_reader *, cpp_num, cpp_num, enum cpp_ttype);
48
static cpp_num num_negate (cpp_num, size_t);
49
static cpp_num num_bitwise_op (cpp_reader *, cpp_num, cpp_num, enum cpp_ttype);
50
static cpp_num num_inequality_op (cpp_reader *, cpp_num, cpp_num,
51
                                  enum cpp_ttype);
52
static cpp_num num_equality_op (cpp_reader *, cpp_num, cpp_num,
53
                                enum cpp_ttype);
54
static cpp_num num_mul (cpp_reader *, cpp_num, cpp_num);
55
static cpp_num num_div_op (cpp_reader *, cpp_num, cpp_num, enum cpp_ttype,
56
                           source_location);
57
static cpp_num num_lshift (cpp_num, size_t, size_t);
58
static cpp_num num_rshift (cpp_num, size_t, size_t);
59
 
60
static cpp_num append_digit (cpp_num, int, int, size_t);
61
static cpp_num parse_defined (cpp_reader *);
62
static cpp_num eval_token (cpp_reader *, const cpp_token *);
63
static struct op *reduce (cpp_reader *, struct op *, enum cpp_ttype);
64
static unsigned int interpret_float_suffix (const uchar *, size_t);
65
static unsigned int interpret_int_suffix (const uchar *, size_t);
66
static void check_promotion (cpp_reader *, const struct op *);
67
 
68
/* Token type abuse to create unary plus and minus operators.  */
69
#define CPP_UPLUS ((enum cpp_ttype) (CPP_LAST_CPP_OP + 1))
70
#define CPP_UMINUS ((enum cpp_ttype) (CPP_LAST_CPP_OP + 2))
71
 
72
/* With -O2, gcc appears to produce nice code, moving the error
73
   message load and subsequent jump completely out of the main path.  */
74
#define SYNTAX_ERROR(msgid) \
75
  do { cpp_error (pfile, CPP_DL_ERROR, msgid); goto syntax_error; } while(0)
76
#define SYNTAX_ERROR2(msgid, arg) \
77
  do { cpp_error (pfile, CPP_DL_ERROR, msgid, arg); goto syntax_error; } \
78
  while(0)
79
 
80
/* Subroutine of cpp_classify_number.  S points to a float suffix of
81
   length LEN, possibly zero.  Returns 0 for an invalid suffix, or a
82
   flag vector describing the suffix.  */
83
static unsigned int
84
interpret_float_suffix (const uchar *s, size_t len)
85
{
86
  size_t flags;
87
  size_t f, d, l, w, q, i;
88
 
89
  flags = 0;
90
  f = d = l = w = q = i = 0;
91
 
92
  /* Process decimal float suffixes, which are two letters starting
93
     with d or D.  Order and case are significant.  */
94
  if (len == 2 && (*s == 'd' || *s == 'D'))
95
    {
96
      bool uppercase = (*s == 'D');
97
      switch (s[1])
98
      {
99
      case 'f': return (!uppercase ? (CPP_N_DFLOAT | CPP_N_SMALL): 0); break;
100
      case 'F': return (uppercase ? (CPP_N_DFLOAT | CPP_N_SMALL) : 0); break;
101
      case 'd': return (!uppercase ? (CPP_N_DFLOAT | CPP_N_MEDIUM): 0); break;
102
      case 'D': return (uppercase ? (CPP_N_DFLOAT | CPP_N_MEDIUM) : 0); break;
103
      case 'l': return (!uppercase ? (CPP_N_DFLOAT | CPP_N_LARGE) : 0); break;
104
      case 'L': return (uppercase ? (CPP_N_DFLOAT | CPP_N_LARGE) : 0); break;
105
      default:
106
        /* Additional two-character suffixes beginning with D are not
107
           for decimal float constants.  */
108
        break;
109
      }
110
    }
111
 
112
  /* Recognize a fixed-point suffix.  */
113
  switch (s[len-1])
114
    {
115
    case 'k': case 'K': flags = CPP_N_ACCUM; break;
116
    case 'r': case 'R': flags = CPP_N_FRACT; break;
117
    default: break;
118
    }
119
 
120
  /* Continue processing a fixed-point suffix.  The suffix is case
121
     insensitive except for ll or LL.  Order is significant.  */
122
  if (flags)
123
    {
124
      if (len == 1)
125
        return flags;
126
      len--;
127
 
128
      if (*s == 'u' || *s == 'U')
129
        {
130
          flags |= CPP_N_UNSIGNED;
131
          if (len == 1)
132
            return flags;
133
          len--;
134
          s++;
135
        }
136
 
137
      switch (*s)
138
      {
139
      case 'h': case 'H':
140
        if (len == 1)
141
          return flags |= CPP_N_SMALL;
142
        break;
143
      case 'l':
144
        if (len == 1)
145
          return flags |= CPP_N_MEDIUM;
146
        if (len == 2 && s[1] == 'l')
147
          return flags |= CPP_N_LARGE;
148
        break;
149
      case 'L':
150
        if (len == 1)
151
          return flags |= CPP_N_MEDIUM;
152
        if (len == 2 && s[1] == 'L')
153
          return flags |= CPP_N_LARGE;
154
        break;
155
      default:
156
        break;
157
      }
158
      /* Anything left at this point is invalid.  */
159
      return 0;
160
    }
161
 
162
  /* In any remaining valid suffix, the case and order don't matter.  */
163
  while (len--)
164
    switch (s[len])
165
      {
166
      case 'f': case 'F': f++; break;
167
      case 'd': case 'D': d++; break;
168
      case 'l': case 'L': l++; break;
169
      case 'w': case 'W': w++; break;
170
      case 'q': case 'Q': q++; break;
171
      case 'i': case 'I':
172
      case 'j': case 'J': i++; break;
173
      default:
174
        return 0;
175
      }
176
 
177
  if (f + d + l + w + q > 1 || i > 1)
178
    return 0;
179
 
180
  return ((i ? CPP_N_IMAGINARY : 0)
181
          | (f ? CPP_N_SMALL :
182
             d ? CPP_N_MEDIUM :
183
             l ? CPP_N_LARGE :
184
             w ? CPP_N_MD_W :
185
             q ? CPP_N_MD_Q : CPP_N_DEFAULT));
186
}
187
 
188
/* Subroutine of cpp_classify_number.  S points to an integer suffix
189
   of length LEN, possibly zero. Returns 0 for an invalid suffix, or a
190
   flag vector describing the suffix.  */
191
static unsigned int
192
interpret_int_suffix (const uchar *s, size_t len)
193
{
194
  size_t u, l, i;
195
 
196
  u = l = i = 0;
197
 
198
  while (len--)
199
    switch (s[len])
200
      {
201
      case 'u': case 'U':       u++; break;
202
      case 'i': case 'I':
203
      case 'j': case 'J':       i++; break;
204
      case 'l': case 'L':       l++;
205
        /* If there are two Ls, they must be adjacent and the same case.  */
206
        if (l == 2 && s[len] != s[len + 1])
207
          return 0;
208
        break;
209
      default:
210
        return 0;
211
      }
212
 
213
  if (l > 2 || u > 1 || i > 1)
214
    return 0;
215
 
216
  return ((i ? CPP_N_IMAGINARY : 0)
217
          | (u ? CPP_N_UNSIGNED : 0)
218
          | ((l == 0) ? CPP_N_SMALL
219
             : (l == 1) ? CPP_N_MEDIUM : CPP_N_LARGE));
220
}
221
 
222
/* Categorize numeric constants according to their field (integer,
223
   floating point, or invalid), radix (decimal, octal, hexadecimal),
224
   and type suffixes.  */
225
unsigned int
226
cpp_classify_number (cpp_reader *pfile, const cpp_token *token)
227
{
228
  const uchar *str = token->val.str.text;
229
  const uchar *limit;
230
  unsigned int max_digit, result, radix;
231
  enum {NOT_FLOAT = 0, AFTER_POINT, AFTER_EXPON} float_flag;
232
  bool seen_digit;
233
 
234
  /* If the lexer has done its job, length one can only be a single
235
     digit.  Fast-path this very common case.  */
236
  if (token->val.str.len == 1)
237
    return CPP_N_INTEGER | CPP_N_SMALL | CPP_N_DECIMAL;
238
 
239
  limit = str + token->val.str.len;
240
  float_flag = NOT_FLOAT;
241
  max_digit = 0;
242
  radix = 10;
243
  seen_digit = false;
244
 
245
  /* First, interpret the radix.  */
246
  if (*str == '0')
247
    {
248
      radix = 8;
249
      str++;
250
 
251
      /* Require at least one hex digit to classify it as hex.  */
252
      if ((*str == 'x' || *str == 'X')
253
          && (str[1] == '.' || ISXDIGIT (str[1])))
254
        {
255
          radix = 16;
256
          str++;
257
        }
258
      else if ((*str == 'b' || *str == 'B') && (str[1] == '0' || str[1] == '1'))
259
        {
260
          radix = 2;
261
          str++;
262
        }
263
    }
264
 
265
  /* Now scan for a well-formed integer or float.  */
266
  for (;;)
267
    {
268
      unsigned int c = *str++;
269
 
270
      if (ISDIGIT (c) || (ISXDIGIT (c) && radix == 16))
271
        {
272
          seen_digit = true;
273
          c = hex_value (c);
274
          if (c > max_digit)
275
            max_digit = c;
276
        }
277
      else if (c == '.')
278
        {
279
          if (float_flag == NOT_FLOAT)
280
            float_flag = AFTER_POINT;
281
          else
282
            SYNTAX_ERROR ("too many decimal points in number");
283
        }
284
      else if ((radix <= 10 && (c == 'e' || c == 'E'))
285
               || (radix == 16 && (c == 'p' || c == 'P')))
286
        {
287
          float_flag = AFTER_EXPON;
288
          break;
289
        }
290
      else
291
        {
292
          /* Start of suffix.  */
293
          str--;
294
          break;
295
        }
296
    }
297
 
298
  /* The suffix may be for decimal fixed-point constants without exponent.  */
299
  if (radix != 16 && float_flag == NOT_FLOAT)
300
    {
301
      result = interpret_float_suffix (str, limit - str);
302
      if ((result & CPP_N_FRACT) || (result & CPP_N_ACCUM))
303
        {
304
          result |= CPP_N_FLOATING;
305
          /* We need to restore the radix to 10, if the radix is 8.  */
306
          if (radix == 8)
307
            radix = 10;
308
 
309
          if (CPP_PEDANTIC (pfile))
310
            cpp_error (pfile, CPP_DL_PEDWARN,
311
                       "fixed-point constants are a GCC extension");
312
          goto syntax_ok;
313
        }
314
      else
315
        result = 0;
316
    }
317
 
318
  if (float_flag != NOT_FLOAT && radix == 8)
319
    radix = 10;
320
 
321
  if (max_digit >= radix)
322
    {
323
      if (radix == 2)
324
        SYNTAX_ERROR2 ("invalid digit \"%c\" in binary constant", '0' + max_digit);
325
      else
326
        SYNTAX_ERROR2 ("invalid digit \"%c\" in octal constant", '0' + max_digit);
327
    }
328
 
329
  if (float_flag != NOT_FLOAT)
330
    {
331
      if (radix == 2)
332
        {
333
          cpp_error (pfile, CPP_DL_ERROR,
334
                     "invalid prefix \"0b\" for floating constant");
335
          return CPP_N_INVALID;
336
        }
337
 
338
      if (radix == 16 && !seen_digit)
339
        SYNTAX_ERROR ("no digits in hexadecimal floating constant");
340
 
341
      if (radix == 16 && CPP_PEDANTIC (pfile) && !CPP_OPTION (pfile, c99))
342
        cpp_error (pfile, CPP_DL_PEDWARN,
343
                   "use of C99 hexadecimal floating constant");
344
 
345
      if (float_flag == AFTER_EXPON)
346
        {
347
          if (*str == '+' || *str == '-')
348
            str++;
349
 
350
          /* Exponent is decimal, even if string is a hex float.  */
351
          if (!ISDIGIT (*str))
352
            SYNTAX_ERROR ("exponent has no digits");
353
 
354
          do
355
            str++;
356
          while (ISDIGIT (*str));
357
        }
358
      else if (radix == 16)
359
        SYNTAX_ERROR ("hexadecimal floating constants require an exponent");
360
 
361
      result = interpret_float_suffix (str, limit - str);
362
      if (result == 0)
363
        {
364
          cpp_error (pfile, CPP_DL_ERROR,
365
                     "invalid suffix \"%.*s\" on floating constant",
366
                     (int) (limit - str), str);
367
          return CPP_N_INVALID;
368
        }
369
 
370
      /* Traditional C didn't accept any floating suffixes.  */
371
      if (limit != str
372
          && CPP_WTRADITIONAL (pfile)
373
          && ! cpp_sys_macro_p (pfile))
374
        cpp_error (pfile, CPP_DL_WARNING,
375
                   "traditional C rejects the \"%.*s\" suffix",
376
                   (int) (limit - str), str);
377
 
378
      /* A suffix for double is a GCC extension via decimal float support.
379
         If the suffix also specifies an imaginary value we'll catch that
380
         later.  */
381
      if ((result == CPP_N_MEDIUM) && CPP_PEDANTIC (pfile))
382
        cpp_error (pfile, CPP_DL_PEDWARN,
383
                   "suffix for double constant is a GCC extension");
384
 
385
      /* Radix must be 10 for decimal floats.  */
386
      if ((result & CPP_N_DFLOAT) && radix != 10)
387
        {
388
          cpp_error (pfile, CPP_DL_ERROR,
389
                     "invalid suffix \"%.*s\" with hexadecimal floating constant",
390
                     (int) (limit - str), str);
391
          return CPP_N_INVALID;
392
        }
393
 
394
      if ((result & (CPP_N_FRACT | CPP_N_ACCUM)) && CPP_PEDANTIC (pfile))
395
        cpp_error (pfile, CPP_DL_PEDWARN,
396
                   "fixed-point constants are a GCC extension");
397
 
398
      if ((result & CPP_N_DFLOAT) && CPP_PEDANTIC (pfile))
399
        cpp_error (pfile, CPP_DL_PEDWARN,
400
                   "decimal float constants are a GCC extension");
401
 
402
      result |= CPP_N_FLOATING;
403
    }
404
  else
405
    {
406
      result = interpret_int_suffix (str, limit - str);
407
      if (result == 0)
408
        {
409
          cpp_error (pfile, CPP_DL_ERROR,
410
                     "invalid suffix \"%.*s\" on integer constant",
411
                     (int) (limit - str), str);
412
          return CPP_N_INVALID;
413
        }
414
 
415
      /* Traditional C only accepted the 'L' suffix.
416
         Suppress warning about 'LL' with -Wno-long-long.  */
417
      if (CPP_WTRADITIONAL (pfile) && ! cpp_sys_macro_p (pfile))
418
        {
419
          int u_or_i = (result & (CPP_N_UNSIGNED|CPP_N_IMAGINARY));
420
          int large = (result & CPP_N_WIDTH) == CPP_N_LARGE;
421
 
422
          if (u_or_i || (large && CPP_OPTION (pfile, warn_long_long)))
423
            cpp_error (pfile, CPP_DL_WARNING,
424
                       "traditional C rejects the \"%.*s\" suffix",
425
                       (int) (limit - str), str);
426
        }
427
 
428
      if ((result & CPP_N_WIDTH) == CPP_N_LARGE
429
          && CPP_OPTION (pfile, warn_long_long))
430
        cpp_error (pfile,
431
                   CPP_OPTION (pfile, c99) ? CPP_DL_WARNING : CPP_DL_PEDWARN,
432
                   CPP_OPTION (pfile, cplusplus)
433
                   ? "use of C++0x long long integer constant"
434
                   : "use of C99 long long integer constant");
435
 
436
      result |= CPP_N_INTEGER;
437
    }
438
 
439
 syntax_ok:
440
  if ((result & CPP_N_IMAGINARY) && CPP_PEDANTIC (pfile))
441
    cpp_error (pfile, CPP_DL_PEDWARN,
442
               "imaginary constants are a GCC extension");
443
  if (radix == 2 && CPP_PEDANTIC (pfile))
444
    cpp_error (pfile, CPP_DL_PEDWARN,
445
               "binary constants are a GCC extension");
446
 
447
  if (radix == 10)
448
    result |= CPP_N_DECIMAL;
449
  else if (radix == 16)
450
    result |= CPP_N_HEX;
451
  else if (radix == 2)
452
    result |= CPP_N_BINARY;
453
  else
454
    result |= CPP_N_OCTAL;
455
 
456
  return result;
457
 
458
 syntax_error:
459
  return CPP_N_INVALID;
460
}
461
 
462
/* cpp_interpret_integer converts an integer constant into a cpp_num,
463
   of precision options->precision.
464
 
465
   We do not provide any interface for decimal->float conversion,
466
   because the preprocessor doesn't need it and we don't want to
467
   drag in GCC's floating point emulator.  */
468
cpp_num
469
cpp_interpret_integer (cpp_reader *pfile, const cpp_token *token,
470
                       unsigned int type)
471
{
472
  const uchar *p, *end;
473
  cpp_num result;
474
 
475
  result.low = 0;
476
  result.high = 0;
477
  result.unsignedp = !!(type & CPP_N_UNSIGNED);
478
  result.overflow = false;
479
 
480
  p = token->val.str.text;
481
  end = p + token->val.str.len;
482
 
483
  /* Common case of a single digit.  */
484
  if (token->val.str.len == 1)
485
    result.low = p[0] - '0';
486
  else
487
    {
488
      cpp_num_part max;
489
      size_t precision = CPP_OPTION (pfile, precision);
490
      unsigned int base = 10, c = 0;
491
      bool overflow = false;
492
 
493
      if ((type & CPP_N_RADIX) == CPP_N_OCTAL)
494
        {
495
          base = 8;
496
          p++;
497
        }
498
      else if ((type & CPP_N_RADIX) == CPP_N_HEX)
499
        {
500
          base = 16;
501
          p += 2;
502
        }
503
      else if ((type & CPP_N_RADIX) == CPP_N_BINARY)
504
        {
505
          base = 2;
506
          p += 2;
507
        }
508
 
509
      /* We can add a digit to numbers strictly less than this without
510
         needing the precision and slowness of double integers.  */
511
      max = ~(cpp_num_part) 0;
512
      if (precision < PART_PRECISION)
513
        max >>= PART_PRECISION - precision;
514
      max = (max - base + 1) / base + 1;
515
 
516
      for (; p < end; p++)
517
        {
518
          c = *p;
519
 
520
          if (ISDIGIT (c) || (base == 16 && ISXDIGIT (c)))
521
            c = hex_value (c);
522
          else
523
            break;
524
 
525
          /* Strict inequality for when max is set to zero.  */
526
          if (result.low < max)
527
            result.low = result.low * base + c;
528
          else
529
            {
530
              result = append_digit (result, c, base, precision);
531
              overflow |= result.overflow;
532
              max = 0;
533
            }
534
        }
535
 
536
      if (overflow)
537
        cpp_error (pfile, CPP_DL_PEDWARN,
538
                   "integer constant is too large for its type");
539
      /* If too big to be signed, consider it unsigned.  Only warn for
540
         decimal numbers.  Traditional numbers were always signed (but
541
         we still honor an explicit U suffix); but we only have
542
         traditional semantics in directives.  */
543
      else if (!result.unsignedp
544
               && !(CPP_OPTION (pfile, traditional)
545
                    && pfile->state.in_directive)
546
               && !num_positive (result, precision))
547
        {
548
          /* This is for constants within the range of uintmax_t but
549
             not that of intmax_t.  For such decimal constants, a
550
             diagnostic is required for C99 as the selected type must
551
             be signed and not having a type is a constraint violation
552
             (DR#298, TC3), so this must be a pedwarn.  For C90,
553
             unsigned long is specified to be used for a constant that
554
             does not fit in signed long; if uintmax_t has the same
555
             range as unsigned long this means only a warning is
556
             appropriate here.  C90 permits the preprocessor to use a
557
             wider range than unsigned long in the compiler, so if
558
             uintmax_t is wider than unsigned long no diagnostic is
559
             required for such constants in preprocessor #if
560
             expressions and the compiler will pedwarn for such
561
             constants outside the range of unsigned long that reach
562
             the compiler so a diagnostic is not required there
563
             either; thus, pedwarn for C99 but use a plain warning for
564
             C90.  */
565
          if (base == 10)
566
            cpp_error (pfile, (CPP_OPTION (pfile, c99)
567
                               ? CPP_DL_PEDWARN
568
                               : CPP_DL_WARNING),
569
                       "integer constant is so large that it is unsigned");
570
          result.unsignedp = true;
571
        }
572
    }
573
 
574
  return result;
575
}
576
 
577
/* Append DIGIT to NUM, a number of PRECISION bits being read in base BASE.  */
578
static cpp_num
579
append_digit (cpp_num num, int digit, int base, size_t precision)
580
{
581
  cpp_num result;
582
  unsigned int shift;
583
  bool overflow;
584
  cpp_num_part add_high, add_low;
585
 
586
  /* Multiply by 2, 8 or 16.  Catching this overflow here means we don't
587
     need to worry about add_high overflowing.  */
588
  switch (base)
589
    {
590
    case 2:
591
      shift = 1;
592
      break;
593
 
594
    case 16:
595
      shift = 4;
596
      break;
597
 
598
    default:
599
      shift = 3;
600
    }
601
  overflow = !!(num.high >> (PART_PRECISION - shift));
602
  result.high = num.high << shift;
603
  result.low = num.low << shift;
604
  result.high |= num.low >> (PART_PRECISION - shift);
605
  result.unsignedp = num.unsignedp;
606
 
607
  if (base == 10)
608
    {
609
      add_low = num.low << 1;
610
      add_high = (num.high << 1) + (num.low >> (PART_PRECISION - 1));
611
    }
612
  else
613
    add_high = add_low = 0;
614
 
615
  if (add_low + digit < add_low)
616
    add_high++;
617
  add_low += digit;
618
 
619
  if (result.low + add_low < result.low)
620
    add_high++;
621
  if (result.high + add_high < result.high)
622
    overflow = true;
623
 
624
  result.low += add_low;
625
  result.high += add_high;
626
  result.overflow = overflow;
627
 
628
  /* The above code catches overflow of a cpp_num type.  This catches
629
     overflow of the (possibly shorter) target precision.  */
630
  num.low = result.low;
631
  num.high = result.high;
632
  result = num_trim (result, precision);
633
  if (!num_eq (result, num))
634
    result.overflow = true;
635
 
636
  return result;
637
}
638
 
639
/* Handle meeting "defined" in a preprocessor expression.  */
640
static cpp_num
641
parse_defined (cpp_reader *pfile)
642
{
643
  cpp_num result;
644
  int paren = 0;
645
  cpp_hashnode *node = 0;
646
  const cpp_token *token;
647
  cpp_context *initial_context = pfile->context;
648
 
649
  /* Don't expand macros.  */
650
  pfile->state.prevent_expansion++;
651
 
652
  token = cpp_get_token (pfile);
653
  if (token->type == CPP_OPEN_PAREN)
654
    {
655
      paren = 1;
656
      token = cpp_get_token (pfile);
657
    }
658
 
659
  if (token->type == CPP_NAME)
660
    {
661
      node = token->val.node.node;
662
      if (paren && cpp_get_token (pfile)->type != CPP_CLOSE_PAREN)
663
        {
664
          cpp_error (pfile, CPP_DL_ERROR, "missing ')' after \"defined\"");
665
          node = 0;
666
        }
667
    }
668
  else
669
    {
670
      cpp_error (pfile, CPP_DL_ERROR,
671
                 "operator \"defined\" requires an identifier");
672
      if (token->flags & NAMED_OP)
673
        {
674
          cpp_token op;
675
 
676
          op.flags = 0;
677
          op.type = token->type;
678
          cpp_error (pfile, CPP_DL_ERROR,
679
                     "(\"%s\" is an alternative token for \"%s\" in C++)",
680
                     cpp_token_as_text (pfile, token),
681
                     cpp_token_as_text (pfile, &op));
682
        }
683
    }
684
 
685
  if (node)
686
    {
687
      if (pfile->context != initial_context && CPP_PEDANTIC (pfile))
688
        cpp_error (pfile, CPP_DL_WARNING,
689
                   "this use of \"defined\" may not be portable");
690
 
691
      _cpp_mark_macro_used (node);
692
      if (!(node->flags & NODE_USED))
693
        {
694
          node->flags |= NODE_USED;
695
          if (node->type == NT_MACRO)
696
            {
697
              if (pfile->cb.used_define)
698
                pfile->cb.used_define (pfile, pfile->directive_line, node);
699
            }
700
          else
701
            {
702
              if (pfile->cb.used_undef)
703
                pfile->cb.used_undef (pfile, pfile->directive_line, node);
704
            }
705
        }
706
 
707
      /* A possible controlling macro of the form #if !defined ().
708
         _cpp_parse_expr checks there was no other junk on the line.  */
709
      pfile->mi_ind_cmacro = node;
710
    }
711
 
712
  pfile->state.prevent_expansion--;
713
 
714
  result.unsignedp = false;
715
  result.high = 0;
716
  result.overflow = false;
717
  result.low = node && node->type == NT_MACRO;
718
  return result;
719
}
720
 
721
/* Convert a token into a CPP_NUMBER (an interpreted preprocessing
722
   number or character constant, or the result of the "defined" or "#"
723
   operators).  */
724
static cpp_num
725
eval_token (cpp_reader *pfile, const cpp_token *token)
726
{
727
  cpp_num result;
728
  unsigned int temp;
729
  int unsignedp = 0;
730
 
731
  result.unsignedp = false;
732
  result.overflow = false;
733
 
734
  switch (token->type)
735
    {
736
    case CPP_NUMBER:
737
      temp = cpp_classify_number (pfile, token);
738
      switch (temp & CPP_N_CATEGORY)
739
        {
740
        case CPP_N_FLOATING:
741
          cpp_error (pfile, CPP_DL_ERROR,
742
                     "floating constant in preprocessor expression");
743
          break;
744
        case CPP_N_INTEGER:
745
          if (!(temp & CPP_N_IMAGINARY))
746
            return cpp_interpret_integer (pfile, token, temp);
747
          cpp_error (pfile, CPP_DL_ERROR,
748
                     "imaginary number in preprocessor expression");
749
          break;
750
 
751
        case CPP_N_INVALID:
752
          /* Error already issued.  */
753
          break;
754
        }
755
      result.high = result.low = 0;
756
      break;
757
 
758
    case CPP_WCHAR:
759
    case CPP_CHAR:
760
    case CPP_CHAR16:
761
    case CPP_CHAR32:
762
      {
763
        cppchar_t cc = cpp_interpret_charconst (pfile, token,
764
                                                &temp, &unsignedp);
765
 
766
        result.high = 0;
767
        result.low = cc;
768
        /* Sign-extend the result if necessary.  */
769
        if (!unsignedp && (cppchar_signed_t) cc < 0)
770
          {
771
            if (PART_PRECISION > BITS_PER_CPPCHAR_T)
772
              result.low |= ~(~(cpp_num_part) 0
773
                              >> (PART_PRECISION - BITS_PER_CPPCHAR_T));
774
            result.high = ~(cpp_num_part) 0;
775
            result = num_trim (result, CPP_OPTION (pfile, precision));
776
          }
777
      }
778
      break;
779
 
780
    case CPP_NAME:
781
      if (token->val.node.node == pfile->spec_nodes.n_defined)
782
        return parse_defined (pfile);
783
      else if (CPP_OPTION (pfile, cplusplus)
784
               && (token->val.node.node == pfile->spec_nodes.n_true
785
                   || token->val.node.node == pfile->spec_nodes.n_false))
786
        {
787
          result.high = 0;
788
          result.low = (token->val.node.node == pfile->spec_nodes.n_true);
789
        }
790
      else
791
        {
792
          result.high = 0;
793
          result.low = 0;
794
          if (CPP_OPTION (pfile, warn_undef) && !pfile->state.skip_eval)
795
            cpp_error (pfile, CPP_DL_WARNING, "\"%s\" is not defined",
796
                       NODE_NAME (token->val.node.node));
797
        }
798
      break;
799
 
800
    case CPP_HASH:
801
      if (!pfile->state.skipping)
802
        {
803
          /* A pedantic warning takes precedence over a deprecated
804
             warning here.  */
805
          if (CPP_PEDANTIC (pfile))
806
            cpp_error (pfile, CPP_DL_PEDWARN,
807
                       "assertions are a GCC extension");
808
          else if (CPP_OPTION (pfile, warn_deprecated))
809
            cpp_error (pfile, CPP_DL_WARNING,
810
                       "assertions are a deprecated extension");
811
        }
812
      _cpp_test_assertion (pfile, &temp);
813
      result.high = 0;
814
      result.low = temp;
815
      break;
816
 
817
    default:
818
      abort ();
819
    }
820
 
821
  result.unsignedp = !!unsignedp;
822
  return result;
823
}
824
 
825
/* Operator precedence and flags table.
826
 
827
After an operator is returned from the lexer, if it has priority less
828
than the operator on the top of the stack, we reduce the stack by one
829
operator and repeat the test.  Since equal priorities do not reduce,
830
this is naturally right-associative.
831
 
832
We handle left-associative operators by decrementing the priority of
833
just-lexed operators by one, but retaining the priority of operators
834
already on the stack.
835
 
836
The remaining cases are '(' and ')'.  We handle '(' by skipping the
837
reduction phase completely.  ')' is given lower priority than
838
everything else, including '(', effectively forcing a reduction of the
839
parenthesized expression.  If there is a matching '(', the routine
840
reduce() exits immediately.  If the normal exit route sees a ')', then
841
there cannot have been a matching '(' and an error message is output.
842
 
843
The parser assumes all shifted operators require a left operand unless
844
the flag NO_L_OPERAND is set.  These semantics are automatic; any
845
extra semantics need to be handled with operator-specific code.  */
846
 
847
/* Flags.  If CHECK_PROMOTION, we warn if the effective sign of an
848
   operand changes because of integer promotions.  */
849
#define NO_L_OPERAND    (1 << 0)
850
#define LEFT_ASSOC      (1 << 1)
851
#define CHECK_PROMOTION (1 << 2)
852
 
853
/* Operator to priority map.  Must be in the same order as the first
854
   N entries of enum cpp_ttype.  */
855
static const struct cpp_operator
856
{
857
  uchar prio;
858
  uchar flags;
859
} optab[] =
860
{
861
  /* EQ */              {0, 0},   /* Shouldn't happen.  */
862
  /* NOT */             {16, NO_L_OPERAND},
863
  /* GREATER */         {12, LEFT_ASSOC | CHECK_PROMOTION},
864
  /* LESS */            {12, LEFT_ASSOC | CHECK_PROMOTION},
865
  /* PLUS */            {14, LEFT_ASSOC | CHECK_PROMOTION},
866
  /* MINUS */           {14, LEFT_ASSOC | CHECK_PROMOTION},
867
  /* MULT */            {15, LEFT_ASSOC | CHECK_PROMOTION},
868
  /* DIV */             {15, LEFT_ASSOC | CHECK_PROMOTION},
869
  /* MOD */             {15, LEFT_ASSOC | CHECK_PROMOTION},
870
  /* AND */             {9, LEFT_ASSOC | CHECK_PROMOTION},
871
  /* OR */              {7, LEFT_ASSOC | CHECK_PROMOTION},
872
  /* XOR */             {8, LEFT_ASSOC | CHECK_PROMOTION},
873
  /* RSHIFT */          {13, LEFT_ASSOC},
874
  /* LSHIFT */          {13, LEFT_ASSOC},
875
 
876
  /* COMPL */           {16, NO_L_OPERAND},
877
  /* AND_AND */         {6, LEFT_ASSOC},
878
  /* OR_OR */           {5, LEFT_ASSOC},
879
  /* Note that QUERY, COLON, and COMMA must have the same precedence.
880
     However, there are some special cases for these in reduce().  */
881
  /* QUERY */           {4, 0},
882
  /* COLON */           {4, LEFT_ASSOC | CHECK_PROMOTION},
883
  /* COMMA */           {4, LEFT_ASSOC},
884
  /* OPEN_PAREN */      {1, NO_L_OPERAND},
885
  /* CLOSE_PAREN */     {0, 0},
886
  /* EOF */             {0, 0},
887
  /* EQ_EQ */           {11, LEFT_ASSOC},
888
  /* NOT_EQ */          {11, LEFT_ASSOC},
889
  /* GREATER_EQ */      {12, LEFT_ASSOC | CHECK_PROMOTION},
890
  /* LESS_EQ */         {12, LEFT_ASSOC | CHECK_PROMOTION},
891
  /* UPLUS */           {16, NO_L_OPERAND},
892
  /* UMINUS */          {16, NO_L_OPERAND}
893
};
894
 
895
/* Parse and evaluate a C expression, reading from PFILE.
896
   Returns the truth value of the expression.
897
 
898
   The implementation is an operator precedence parser, i.e. a
899
   bottom-up parser, using a stack for not-yet-reduced tokens.
900
 
901
   The stack base is op_stack, and the current stack pointer is 'top'.
902
   There is a stack element for each operator (only), and the most
903
   recently pushed operator is 'top->op'.  An operand (value) is
904
   stored in the 'value' field of the stack element of the operator
905
   that precedes it.  */
906
bool
907
_cpp_parse_expr (cpp_reader *pfile, bool is_if)
908
{
909
  struct op *top = pfile->op_stack;
910
  unsigned int lex_count;
911
  bool saw_leading_not, want_value = true;
912
 
913
  pfile->state.skip_eval = 0;
914
 
915
  /* Set up detection of #if ! defined().  */
916
  pfile->mi_ind_cmacro = 0;
917
  saw_leading_not = false;
918
  lex_count = 0;
919
 
920
  /* Lowest priority operator prevents further reductions.  */
921
  top->op = CPP_EOF;
922
 
923
  for (;;)
924
    {
925
      struct op op;
926
 
927
      lex_count++;
928
      op.token = cpp_get_token (pfile);
929
      op.op = op.token->type;
930
      op.loc = op.token->src_loc;
931
 
932
      switch (op.op)
933
        {
934
          /* These tokens convert into values.  */
935
        case CPP_NUMBER:
936
        case CPP_CHAR:
937
        case CPP_WCHAR:
938
        case CPP_CHAR16:
939
        case CPP_CHAR32:
940
        case CPP_NAME:
941
        case CPP_HASH:
942
          if (!want_value)
943
            SYNTAX_ERROR2 ("missing binary operator before token \"%s\"",
944
                           cpp_token_as_text (pfile, op.token));
945
          want_value = false;
946
          top->value = eval_token (pfile, op.token);
947
          continue;
948
 
949
        case CPP_NOT:
950
          saw_leading_not = lex_count == 1;
951
          break;
952
        case CPP_PLUS:
953
          if (want_value)
954
            op.op = CPP_UPLUS;
955
          break;
956
        case CPP_MINUS:
957
          if (want_value)
958
            op.op = CPP_UMINUS;
959
          break;
960
 
961
        default:
962
          if ((int) op.op <= (int) CPP_EQ || (int) op.op >= (int) CPP_PLUS_EQ)
963
            SYNTAX_ERROR2 ("token \"%s\" is not valid in preprocessor expressions",
964
                           cpp_token_as_text (pfile, op.token));
965
          break;
966
        }
967
 
968
      /* Check we have a value or operator as appropriate.  */
969
      if (optab[op.op].flags & NO_L_OPERAND)
970
        {
971
          if (!want_value)
972
            SYNTAX_ERROR2 ("missing binary operator before token \"%s\"",
973
                           cpp_token_as_text (pfile, op.token));
974
        }
975
      else if (want_value)
976
        {
977
          /* We want a number (or expression) and haven't got one.
978
             Try to emit a specific diagnostic.  */
979
          if (op.op == CPP_CLOSE_PAREN && top->op == CPP_OPEN_PAREN)
980
            SYNTAX_ERROR ("missing expression between '(' and ')'");
981
 
982
          if (op.op == CPP_EOF && top->op == CPP_EOF)
983
            SYNTAX_ERROR2 ("%s with no expression", is_if ? "#if" : "#elif");
984
 
985
          if (top->op != CPP_EOF && top->op != CPP_OPEN_PAREN)
986
            SYNTAX_ERROR2 ("operator '%s' has no right operand",
987
                           cpp_token_as_text (pfile, top->token));
988
          else if (op.op == CPP_CLOSE_PAREN || op.op == CPP_EOF)
989
            /* Complain about missing paren during reduction.  */;
990
          else
991
            SYNTAX_ERROR2 ("operator '%s' has no left operand",
992
                           cpp_token_as_text (pfile, op.token));
993
        }
994
 
995
      top = reduce (pfile, top, op.op);
996
      if (!top)
997
        goto syntax_error;
998
 
999
      if (op.op == CPP_EOF)
1000
        break;
1001
 
1002
      switch (op.op)
1003
        {
1004
        case CPP_CLOSE_PAREN:
1005
          continue;
1006
        case CPP_OR_OR:
1007
          if (!num_zerop (top->value))
1008
            pfile->state.skip_eval++;
1009
          break;
1010
        case CPP_AND_AND:
1011
        case CPP_QUERY:
1012
          if (num_zerop (top->value))
1013
            pfile->state.skip_eval++;
1014
          break;
1015
        case CPP_COLON:
1016
          if (top->op != CPP_QUERY)
1017
            SYNTAX_ERROR (" ':' without preceding '?'");
1018
          if (!num_zerop (top[-1].value)) /* Was '?' condition true?  */
1019
            pfile->state.skip_eval++;
1020
          else
1021
            pfile->state.skip_eval--;
1022
        default:
1023
          break;
1024
        }
1025
 
1026
      want_value = true;
1027
 
1028
      /* Check for and handle stack overflow.  */
1029
      if (++top == pfile->op_limit)
1030
        top = _cpp_expand_op_stack (pfile);
1031
 
1032
      top->op = op.op;
1033
      top->token = op.token;
1034
      top->loc = op.token->src_loc;
1035
    }
1036
 
1037
  /* The controlling macro expression is only valid if we called lex 3
1038
     times: <!> <defined expression> and <EOF>.  push_conditional ()
1039
     checks that we are at top-of-file.  */
1040
  if (pfile->mi_ind_cmacro && !(saw_leading_not && lex_count == 3))
1041
    pfile->mi_ind_cmacro = 0;
1042
 
1043
  if (top != pfile->op_stack)
1044
    {
1045
      cpp_error (pfile, CPP_DL_ICE, "unbalanced stack in %s",
1046
                 is_if ? "#if" : "#elif");
1047
    syntax_error:
1048
      return false;  /* Return false on syntax error.  */
1049
    }
1050
 
1051
  return !num_zerop (top->value);
1052
}
1053
 
1054
/* Reduce the operator / value stack if possible, in preparation for
1055
   pushing operator OP.  Returns NULL on error, otherwise the top of
1056
   the stack.  */
1057
static struct op *
1058
reduce (cpp_reader *pfile, struct op *top, enum cpp_ttype op)
1059
{
1060
  unsigned int prio;
1061
 
1062
  if (top->op <= CPP_EQ || top->op > CPP_LAST_CPP_OP + 2)
1063
    {
1064
    bad_op:
1065
      cpp_error (pfile, CPP_DL_ICE, "impossible operator '%u'", top->op);
1066
      return 0;
1067
    }
1068
 
1069
  if (op == CPP_OPEN_PAREN)
1070
    return top;
1071
 
1072
  /* Decrement the priority of left-associative operators to force a
1073
     reduction with operators of otherwise equal priority.  */
1074
  prio = optab[op].prio - ((optab[op].flags & LEFT_ASSOC) != 0);
1075
  while (prio < optab[top->op].prio)
1076
    {
1077
      if (CPP_OPTION (pfile, warn_num_sign_change)
1078
          && optab[top->op].flags & CHECK_PROMOTION)
1079
        check_promotion (pfile, top);
1080
 
1081
      switch (top->op)
1082
        {
1083
        case CPP_UPLUS:
1084
        case CPP_UMINUS:
1085
        case CPP_NOT:
1086
        case CPP_COMPL:
1087
          top[-1].value = num_unary_op (pfile, top->value, top->op);
1088
          top[-1].loc = top->loc;
1089
          break;
1090
 
1091
        case CPP_PLUS:
1092
        case CPP_MINUS:
1093
        case CPP_RSHIFT:
1094
        case CPP_LSHIFT:
1095
        case CPP_COMMA:
1096
          top[-1].value = num_binary_op (pfile, top[-1].value,
1097
                                         top->value, top->op);
1098
          top[-1].loc = top->loc;
1099
          break;
1100
 
1101
        case CPP_GREATER:
1102
        case CPP_LESS:
1103
        case CPP_GREATER_EQ:
1104
        case CPP_LESS_EQ:
1105
          top[-1].value
1106
            = num_inequality_op (pfile, top[-1].value, top->value, top->op);
1107
          top[-1].loc = top->loc;
1108
          break;
1109
 
1110
        case CPP_EQ_EQ:
1111
        case CPP_NOT_EQ:
1112
          top[-1].value
1113
            = num_equality_op (pfile, top[-1].value, top->value, top->op);
1114
          top[-1].loc = top->loc;
1115
          break;
1116
 
1117
        case CPP_AND:
1118
        case CPP_OR:
1119
        case CPP_XOR:
1120
          top[-1].value
1121
            = num_bitwise_op (pfile, top[-1].value, top->value, top->op);
1122
          top[-1].loc = top->loc;
1123
          break;
1124
 
1125
        case CPP_MULT:
1126
          top[-1].value = num_mul (pfile, top[-1].value, top->value);
1127
          top[-1].loc = top->loc;
1128
          break;
1129
 
1130
        case CPP_DIV:
1131
        case CPP_MOD:
1132
          top[-1].value = num_div_op (pfile, top[-1].value,
1133
                                      top->value, top->op, top->loc);
1134
          top[-1].loc = top->loc;
1135
          break;
1136
 
1137
        case CPP_OR_OR:
1138
          top--;
1139
          if (!num_zerop (top->value))
1140
            pfile->state.skip_eval--;
1141
          top->value.low = (!num_zerop (top->value)
1142
                            || !num_zerop (top[1].value));
1143
          top->value.high = 0;
1144
          top->value.unsignedp = false;
1145
          top->value.overflow = false;
1146
          top->loc = top[1].loc;
1147
          continue;
1148
 
1149
        case CPP_AND_AND:
1150
          top--;
1151
          if (num_zerop (top->value))
1152
            pfile->state.skip_eval--;
1153
          top->value.low = (!num_zerop (top->value)
1154
                            && !num_zerop (top[1].value));
1155
          top->value.high = 0;
1156
          top->value.unsignedp = false;
1157
          top->value.overflow = false;
1158
          top->loc = top[1].loc;
1159
          continue;
1160
 
1161
        case CPP_OPEN_PAREN:
1162
          if (op != CPP_CLOSE_PAREN)
1163
            {
1164
              cpp_error_with_line (pfile, CPP_DL_ERROR,
1165
                                   top->token->src_loc,
1166
                                   0, "missing ')' in expression");
1167
              return 0;
1168
            }
1169
          top--;
1170
          top->value = top[1].value;
1171
          top->loc = top[1].loc;
1172
          return top;
1173
 
1174
        case CPP_COLON:
1175
          top -= 2;
1176
          if (!num_zerop (top->value))
1177
            {
1178
              pfile->state.skip_eval--;
1179
              top->value = top[1].value;
1180
              top->loc = top[1].loc;
1181
            }
1182
          else
1183
            {
1184
              top->value = top[2].value;
1185
              top->loc = top[2].loc;
1186
            }
1187
          top->value.unsignedp = (top[1].value.unsignedp
1188
                                  || top[2].value.unsignedp);
1189
          continue;
1190
 
1191
        case CPP_QUERY:
1192
          /* COMMA and COLON should not reduce a QUERY operator.  */
1193
          if (op == CPP_COMMA || op == CPP_COLON)
1194
            return top;
1195
          cpp_error (pfile, CPP_DL_ERROR, "'?' without following ':'");
1196
          return 0;
1197
 
1198
        default:
1199
          goto bad_op;
1200
        }
1201
 
1202
      top--;
1203
      if (top->value.overflow && !pfile->state.skip_eval)
1204
        cpp_error (pfile, CPP_DL_PEDWARN,
1205
                   "integer overflow in preprocessor expression");
1206
    }
1207
 
1208
  if (op == CPP_CLOSE_PAREN)
1209
    {
1210
      cpp_error (pfile, CPP_DL_ERROR, "missing '(' in expression");
1211
      return 0;
1212
    }
1213
 
1214
  return top;
1215
}
1216
 
1217
/* Returns the position of the old top of stack after expansion.  */
1218
struct op *
1219
_cpp_expand_op_stack (cpp_reader *pfile)
1220
{
1221
  size_t old_size = (size_t) (pfile->op_limit - pfile->op_stack);
1222
  size_t new_size = old_size * 2 + 20;
1223
 
1224
  pfile->op_stack = XRESIZEVEC (struct op, pfile->op_stack, new_size);
1225
  pfile->op_limit = pfile->op_stack + new_size;
1226
 
1227
  return pfile->op_stack + old_size;
1228
}
1229
 
1230
/* Emits a warning if the effective sign of either operand of OP
1231
   changes because of integer promotions.  */
1232
static void
1233
check_promotion (cpp_reader *pfile, const struct op *op)
1234
{
1235
  if (op->value.unsignedp == op[-1].value.unsignedp)
1236
    return;
1237
 
1238
  if (op->value.unsignedp)
1239
    {
1240
      if (!num_positive (op[-1].value, CPP_OPTION (pfile, precision)))
1241
        cpp_error_with_line (pfile, CPP_DL_WARNING, op[-1].loc, 0,
1242
                             "the left operand of \"%s\" changes sign when promoted",
1243
                             cpp_token_as_text (pfile, op->token));
1244
    }
1245
  else if (!num_positive (op->value, CPP_OPTION (pfile, precision)))
1246
    cpp_error_with_line (pfile, CPP_DL_WARNING, op->loc, 0,
1247
               "the right operand of \"%s\" changes sign when promoted",
1248
               cpp_token_as_text (pfile, op->token));
1249
}
1250
 
1251
/* Clears the unused high order bits of the number pointed to by PNUM.  */
1252
static cpp_num
1253
num_trim (cpp_num num, size_t precision)
1254
{
1255
  if (precision > PART_PRECISION)
1256
    {
1257
      precision -= PART_PRECISION;
1258
      if (precision < PART_PRECISION)
1259
        num.high &= ((cpp_num_part) 1 << precision) - 1;
1260
    }
1261
  else
1262
    {
1263
      if (precision < PART_PRECISION)
1264
        num.low &= ((cpp_num_part) 1 << precision) - 1;
1265
      num.high = 0;
1266
    }
1267
 
1268
  return num;
1269
}
1270
 
1271
/* True iff A (presumed signed) >= 0.  */
1272
static bool
1273
num_positive (cpp_num num, size_t precision)
1274
{
1275
  if (precision > PART_PRECISION)
1276
    {
1277
      precision -= PART_PRECISION;
1278
      return (num.high & (cpp_num_part) 1 << (precision - 1)) == 0;
1279
    }
1280
 
1281
  return (num.low & (cpp_num_part) 1 << (precision - 1)) == 0;
1282
}
1283
 
1284
/* Sign extend a number, with PRECISION significant bits and all
1285
   others assumed clear, to fill out a cpp_num structure.  */
1286
cpp_num
1287
cpp_num_sign_extend (cpp_num num, size_t precision)
1288
{
1289
  if (!num.unsignedp)
1290
    {
1291
      if (precision > PART_PRECISION)
1292
        {
1293
          precision -= PART_PRECISION;
1294
          if (precision < PART_PRECISION
1295
              && (num.high & (cpp_num_part) 1 << (precision - 1)))
1296
            num.high |= ~(~(cpp_num_part) 0 >> (PART_PRECISION - precision));
1297
        }
1298
      else if (num.low & (cpp_num_part) 1 << (precision - 1))
1299
        {
1300
          if (precision < PART_PRECISION)
1301
            num.low |= ~(~(cpp_num_part) 0 >> (PART_PRECISION - precision));
1302
          num.high = ~(cpp_num_part) 0;
1303
        }
1304
    }
1305
 
1306
  return num;
1307
}
1308
 
1309
/* Returns the negative of NUM.  */
1310
static cpp_num
1311
num_negate (cpp_num num, size_t precision)
1312
{
1313
  cpp_num copy;
1314
 
1315
  copy = num;
1316
  num.high = ~num.high;
1317
  num.low = ~num.low;
1318
  if (++num.low == 0)
1319
    num.high++;
1320
  num = num_trim (num, precision);
1321
  num.overflow = (!num.unsignedp && num_eq (num, copy) && !num_zerop (num));
1322
 
1323
  return num;
1324
}
1325
 
1326
/* Returns true if A >= B.  */
1327
static bool
1328
num_greater_eq (cpp_num pa, cpp_num pb, size_t precision)
1329
{
1330
  bool unsignedp;
1331
 
1332
  unsignedp = pa.unsignedp || pb.unsignedp;
1333
 
1334
  if (!unsignedp)
1335
    {
1336
      /* Both numbers have signed type.  If they are of different
1337
       sign, the answer is the sign of A.  */
1338
      unsignedp = num_positive (pa, precision);
1339
 
1340
      if (unsignedp != num_positive (pb, precision))
1341
        return unsignedp;
1342
 
1343
      /* Otherwise we can do an unsigned comparison.  */
1344
    }
1345
 
1346
  return (pa.high > pb.high) || (pa.high == pb.high && pa.low >= pb.low);
1347
}
1348
 
1349
/* Returns LHS OP RHS, where OP is a bit-wise operation.  */
1350
static cpp_num
1351
num_bitwise_op (cpp_reader *pfile ATTRIBUTE_UNUSED,
1352
                cpp_num lhs, cpp_num rhs, enum cpp_ttype op)
1353
{
1354
  lhs.overflow = false;
1355
  lhs.unsignedp = lhs.unsignedp || rhs.unsignedp;
1356
 
1357
  /* As excess precision is zeroed, there is no need to num_trim () as
1358
     these operations cannot introduce a set bit there.  */
1359
  if (op == CPP_AND)
1360
    {
1361
      lhs.low &= rhs.low;
1362
      lhs.high &= rhs.high;
1363
    }
1364
  else if (op == CPP_OR)
1365
    {
1366
      lhs.low |= rhs.low;
1367
      lhs.high |= rhs.high;
1368
    }
1369
  else
1370
    {
1371
      lhs.low ^= rhs.low;
1372
      lhs.high ^= rhs.high;
1373
    }
1374
 
1375
  return lhs;
1376
}
1377
 
1378
/* Returns LHS OP RHS, where OP is an inequality.  */
1379
static cpp_num
1380
num_inequality_op (cpp_reader *pfile, cpp_num lhs, cpp_num rhs,
1381
                   enum cpp_ttype op)
1382
{
1383
  bool gte = num_greater_eq (lhs, rhs, CPP_OPTION (pfile, precision));
1384
 
1385
  if (op == CPP_GREATER_EQ)
1386
    lhs.low = gte;
1387
  else if (op == CPP_LESS)
1388
    lhs.low = !gte;
1389
  else if (op == CPP_GREATER)
1390
    lhs.low = gte && !num_eq (lhs, rhs);
1391
  else /* CPP_LESS_EQ.  */
1392
    lhs.low = !gte || num_eq (lhs, rhs);
1393
 
1394
  lhs.high = 0;
1395
  lhs.overflow = false;
1396
  lhs.unsignedp = false;
1397
  return lhs;
1398
}
1399
 
1400
/* Returns LHS OP RHS, where OP is == or !=.  */
1401
static cpp_num
1402
num_equality_op (cpp_reader *pfile ATTRIBUTE_UNUSED,
1403
                 cpp_num lhs, cpp_num rhs, enum cpp_ttype op)
1404
{
1405
  /* Work around a 3.0.4 bug; see PR 6950.  */
1406
  bool eq = num_eq (lhs, rhs);
1407
  if (op == CPP_NOT_EQ)
1408
    eq = !eq;
1409
  lhs.low = eq;
1410
  lhs.high = 0;
1411
  lhs.overflow = false;
1412
  lhs.unsignedp = false;
1413
  return lhs;
1414
}
1415
 
1416
/* Shift NUM, of width PRECISION, right by N bits.  */
1417
static cpp_num
1418
num_rshift (cpp_num num, size_t precision, size_t n)
1419
{
1420
  cpp_num_part sign_mask;
1421
  bool x = num_positive (num, precision);
1422
 
1423
  if (num.unsignedp || x)
1424
    sign_mask = 0;
1425
  else
1426
    sign_mask = ~(cpp_num_part) 0;
1427
 
1428
  if (n >= precision)
1429
    num.high = num.low = sign_mask;
1430
  else
1431
    {
1432
      /* Sign-extend.  */
1433
      if (precision < PART_PRECISION)
1434
        num.high = sign_mask, num.low |= sign_mask << precision;
1435
      else if (precision < 2 * PART_PRECISION)
1436
        num.high |= sign_mask << (precision - PART_PRECISION);
1437
 
1438
      if (n >= PART_PRECISION)
1439
        {
1440
          n -= PART_PRECISION;
1441
          num.low = num.high;
1442
          num.high = sign_mask;
1443
        }
1444
 
1445
      if (n)
1446
        {
1447
          num.low = (num.low >> n) | (num.high << (PART_PRECISION - n));
1448
          num.high = (num.high >> n) | (sign_mask << (PART_PRECISION - n));
1449
        }
1450
    }
1451
 
1452
  num = num_trim (num, precision);
1453
  num.overflow = false;
1454
  return num;
1455
}
1456
 
1457
/* Shift NUM, of width PRECISION, left by N bits.  */
1458
static cpp_num
1459
num_lshift (cpp_num num, size_t precision, size_t n)
1460
{
1461
  if (n >= precision)
1462
    {
1463
      num.overflow = !num.unsignedp && !num_zerop (num);
1464
      num.high = num.low = 0;
1465
    }
1466
  else
1467
    {
1468
      cpp_num orig, maybe_orig;
1469
      size_t m = n;
1470
 
1471
      orig = num;
1472
      if (m >= PART_PRECISION)
1473
        {
1474
          m -= PART_PRECISION;
1475
          num.high = num.low;
1476
          num.low = 0;
1477
        }
1478
      if (m)
1479
        {
1480
          num.high = (num.high << m) | (num.low >> (PART_PRECISION - m));
1481
          num.low <<= m;
1482
        }
1483
      num = num_trim (num, precision);
1484
 
1485
      if (num.unsignedp)
1486
        num.overflow = false;
1487
      else
1488
        {
1489
          maybe_orig = num_rshift (num, precision, n);
1490
          num.overflow = !num_eq (orig, maybe_orig);
1491
        }
1492
    }
1493
 
1494
  return num;
1495
}
1496
 
1497
/* The four unary operators: +, -, ! and ~.  */
1498
static cpp_num
1499
num_unary_op (cpp_reader *pfile, cpp_num num, enum cpp_ttype op)
1500
{
1501
  switch (op)
1502
    {
1503
    case CPP_UPLUS:
1504
      if (CPP_WTRADITIONAL (pfile) && !pfile->state.skip_eval)
1505
        cpp_error (pfile, CPP_DL_WARNING,
1506
                   "traditional C rejects the unary plus operator");
1507
      num.overflow = false;
1508
      break;
1509
 
1510
    case CPP_UMINUS:
1511
      num = num_negate (num, CPP_OPTION (pfile, precision));
1512
      break;
1513
 
1514
    case CPP_COMPL:
1515
      num.high = ~num.high;
1516
      num.low = ~num.low;
1517
      num = num_trim (num, CPP_OPTION (pfile, precision));
1518
      num.overflow = false;
1519
      break;
1520
 
1521
    default: /* case CPP_NOT: */
1522
      num.low = num_zerop (num);
1523
      num.high = 0;
1524
      num.overflow = false;
1525
      num.unsignedp = false;
1526
      break;
1527
    }
1528
 
1529
  return num;
1530
}
1531
 
1532
/* The various binary operators.  */
1533
static cpp_num
1534
num_binary_op (cpp_reader *pfile, cpp_num lhs, cpp_num rhs, enum cpp_ttype op)
1535
{
1536
  cpp_num result;
1537
  size_t precision = CPP_OPTION (pfile, precision);
1538
  size_t n;
1539
 
1540
  switch (op)
1541
    {
1542
      /* Shifts.  */
1543
    case CPP_LSHIFT:
1544
    case CPP_RSHIFT:
1545
      if (!rhs.unsignedp && !num_positive (rhs, precision))
1546
        {
1547
          /* A negative shift is a positive shift the other way.  */
1548
          if (op == CPP_LSHIFT)
1549
            op = CPP_RSHIFT;
1550
          else
1551
            op = CPP_LSHIFT;
1552
          rhs = num_negate (rhs, precision);
1553
        }
1554
      if (rhs.high)
1555
        n = ~0;                  /* Maximal.  */
1556
      else
1557
        n = rhs.low;
1558
      if (op == CPP_LSHIFT)
1559
        lhs = num_lshift (lhs, precision, n);
1560
      else
1561
        lhs = num_rshift (lhs, precision, n);
1562
      break;
1563
 
1564
      /* Arithmetic.  */
1565
    case CPP_MINUS:
1566
      rhs = num_negate (rhs, precision);
1567
    case CPP_PLUS:
1568
      result.low = lhs.low + rhs.low;
1569
      result.high = lhs.high + rhs.high;
1570
      if (result.low < lhs.low)
1571
        result.high++;
1572
      result.unsignedp = lhs.unsignedp || rhs.unsignedp;
1573
      result.overflow = false;
1574
 
1575
      result = num_trim (result, precision);
1576
      if (!result.unsignedp)
1577
        {
1578
          bool lhsp = num_positive (lhs, precision);
1579
          result.overflow = (lhsp == num_positive (rhs, precision)
1580
                             && lhsp != num_positive (result, precision));
1581
        }
1582
      return result;
1583
 
1584
      /* Comma.  */
1585
    default: /* case CPP_COMMA: */
1586
      if (CPP_PEDANTIC (pfile) && (!CPP_OPTION (pfile, c99)
1587
                                   || !pfile->state.skip_eval))
1588
        cpp_error (pfile, CPP_DL_PEDWARN,
1589
                   "comma operator in operand of #if");
1590
      lhs = rhs;
1591
      break;
1592
    }
1593
 
1594
  return lhs;
1595
}
1596
 
1597
/* Multiplies two unsigned cpp_num_parts to give a cpp_num.  This
1598
   cannot overflow.  */
1599
static cpp_num
1600
num_part_mul (cpp_num_part lhs, cpp_num_part rhs)
1601
{
1602
  cpp_num result;
1603
  cpp_num_part middle[2], temp;
1604
 
1605
  result.low = LOW_PART (lhs) * LOW_PART (rhs);
1606
  result.high = HIGH_PART (lhs) * HIGH_PART (rhs);
1607
 
1608
  middle[0] = LOW_PART (lhs) * HIGH_PART (rhs);
1609
  middle[1] = HIGH_PART (lhs) * LOW_PART (rhs);
1610
 
1611
  temp = result.low;
1612
  result.low += LOW_PART (middle[0]) << (PART_PRECISION / 2);
1613
  if (result.low < temp)
1614
    result.high++;
1615
 
1616
  temp = result.low;
1617
  result.low += LOW_PART (middle[1]) << (PART_PRECISION / 2);
1618
  if (result.low < temp)
1619
    result.high++;
1620
 
1621
  result.high += HIGH_PART (middle[0]);
1622
  result.high += HIGH_PART (middle[1]);
1623
  result.unsignedp = true;
1624
  result.overflow = false;
1625
 
1626
  return result;
1627
}
1628
 
1629
/* Multiply two preprocessing numbers.  */
1630
static cpp_num
1631
num_mul (cpp_reader *pfile, cpp_num lhs, cpp_num rhs)
1632
{
1633
  cpp_num result, temp;
1634
  bool unsignedp = lhs.unsignedp || rhs.unsignedp;
1635
  bool overflow, negate = false;
1636
  size_t precision = CPP_OPTION (pfile, precision);
1637
 
1638
  /* Prepare for unsigned multiplication.  */
1639
  if (!unsignedp)
1640
    {
1641
      if (!num_positive (lhs, precision))
1642
        negate = !negate, lhs = num_negate (lhs, precision);
1643
      if (!num_positive (rhs, precision))
1644
        negate = !negate, rhs = num_negate (rhs, precision);
1645
    }
1646
 
1647
  overflow = lhs.high && rhs.high;
1648
  result = num_part_mul (lhs.low, rhs.low);
1649
 
1650
  temp = num_part_mul (lhs.high, rhs.low);
1651
  result.high += temp.low;
1652
  if (temp.high)
1653
    overflow = true;
1654
 
1655
  temp = num_part_mul (lhs.low, rhs.high);
1656
  result.high += temp.low;
1657
  if (temp.high)
1658
    overflow = true;
1659
 
1660
  temp.low = result.low, temp.high = result.high;
1661
  result = num_trim (result, precision);
1662
  if (!num_eq (result, temp))
1663
    overflow = true;
1664
 
1665
  if (negate)
1666
    result = num_negate (result, precision);
1667
 
1668
  if (unsignedp)
1669
    result.overflow = false;
1670
  else
1671
    result.overflow = overflow || (num_positive (result, precision) ^ !negate
1672
                                   && !num_zerop (result));
1673
  result.unsignedp = unsignedp;
1674
 
1675
  return result;
1676
}
1677
 
1678
/* Divide two preprocessing numbers, LHS and RHS, returning the answer
1679
   or the remainder depending upon OP. LOCATION is the source location
1680
   of this operator (for diagnostics).  */
1681
 
1682
static cpp_num
1683
num_div_op (cpp_reader *pfile, cpp_num lhs, cpp_num rhs, enum cpp_ttype op,
1684
            source_location location)
1685
{
1686
  cpp_num result, sub;
1687
  cpp_num_part mask;
1688
  bool unsignedp = lhs.unsignedp || rhs.unsignedp;
1689
  bool negate = false, lhs_neg = false;
1690
  size_t i, precision = CPP_OPTION (pfile, precision);
1691
 
1692
  /* Prepare for unsigned division.  */
1693
  if (!unsignedp)
1694
    {
1695
      if (!num_positive (lhs, precision))
1696
        negate = !negate, lhs_neg = true, lhs = num_negate (lhs, precision);
1697
      if (!num_positive (rhs, precision))
1698
        negate = !negate, rhs = num_negate (rhs, precision);
1699
    }
1700
 
1701
  /* Find the high bit.  */
1702
  if (rhs.high)
1703
    {
1704
      i = precision - 1;
1705
      mask = (cpp_num_part) 1 << (i - PART_PRECISION);
1706
      for (; ; i--, mask >>= 1)
1707
        if (rhs.high & mask)
1708
          break;
1709
    }
1710
  else if (rhs.low)
1711
    {
1712
      if (precision > PART_PRECISION)
1713
        i = precision - PART_PRECISION - 1;
1714
      else
1715
        i = precision - 1;
1716
      mask = (cpp_num_part) 1 << i;
1717
      for (; ; i--, mask >>= 1)
1718
        if (rhs.low & mask)
1719
          break;
1720
    }
1721
  else
1722
    {
1723
      if (!pfile->state.skip_eval)
1724
        cpp_error_with_line (pfile, CPP_DL_ERROR, location, 0,
1725
                             "division by zero in #if");
1726
      return lhs;
1727
    }
1728
 
1729
  /* First nonzero bit of RHS is bit I.  Do naive division by
1730
     shifting the RHS fully left, and subtracting from LHS if LHS is
1731
     at least as big, and then repeating but with one less shift.
1732
     This is not very efficient, but is easy to understand.  */
1733
 
1734
  rhs.unsignedp = true;
1735
  lhs.unsignedp = true;
1736
  i = precision - i - 1;
1737
  sub = num_lshift (rhs, precision, i);
1738
 
1739
  result.high = result.low = 0;
1740
  for (;;)
1741
    {
1742
      if (num_greater_eq (lhs, sub, precision))
1743
        {
1744
          lhs = num_binary_op (pfile, lhs, sub, CPP_MINUS);
1745
          if (i >= PART_PRECISION)
1746
            result.high |= (cpp_num_part) 1 << (i - PART_PRECISION);
1747
          else
1748
            result.low |= (cpp_num_part) 1 << i;
1749
        }
1750
      if (i-- == 0)
1751
        break;
1752
      sub.low = (sub.low >> 1) | (sub.high << (PART_PRECISION - 1));
1753
      sub.high >>= 1;
1754
    }
1755
 
1756
  /* We divide so that the remainder has the sign of the LHS.  */
1757
  if (op == CPP_DIV)
1758
    {
1759
      result.unsignedp = unsignedp;
1760
      result.overflow = false;
1761
      if (!unsignedp)
1762
        {
1763
          if (negate)
1764
            result = num_negate (result, precision);
1765
          result.overflow = (num_positive (result, precision) ^ !negate
1766
                             && !num_zerop (result));
1767
        }
1768
 
1769
      return result;
1770
    }
1771
 
1772
  /* CPP_MOD.  */
1773
  lhs.unsignedp = unsignedp;
1774
  lhs.overflow = false;
1775
  if (lhs_neg)
1776
    lhs = num_negate (lhs, precision);
1777
 
1778
  return lhs;
1779
}

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