1/* RTL reader for GCC.
2   Copyright (C) 1987-2015 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3.  If not see
18<http://www.gnu.org/licenses/>.  */
19
20#include "bconfig.h"
21
22/* Disable rtl checking; it conflicts with the iterator handling.  */
23#undef ENABLE_RTL_CHECKING
24
25#include "system.h"
26#include "coretypes.h"
27#include "tm.h"
28#include "rtl.h"
29#include "obstack.h"
30#include "hashtab.h"
31#include "read-md.h"
32#include "gensupport.h"
33
34/* One element in a singly-linked list of (integer, string) pairs.  */
35struct map_value {
36  struct map_value *next;
37  int number;
38  const char *string;
39};
40
41/* Maps an iterator or attribute name to a list of (integer, string) pairs.
42   The integers are iterator values; the strings are either C conditions
43   or attribute values.  */
44struct mapping {
45  /* The name of the iterator or attribute.  */
46  const char *name;
47
48  /* The group (modes or codes) to which the iterator or attribute belongs.  */
49  struct iterator_group *group;
50
51  /* The list of (integer, string) pairs.  */
52  struct map_value *values;
53
54  /* For iterators, records the current value of the iterator.  */
55  struct map_value *current_value;
56};
57
58/* Vector definitions for the above.  */
59typedef struct mapping *mapping_ptr;
60
61/* A structure for abstracting the common parts of iterators.  */
62struct iterator_group {
63  /* Tables of "mapping" structures, one for attributes and one for
64     iterators.  */
65  htab_t attrs, iterators;
66
67  /* Treat the given string as the name of a standard mode, etc., and
68     return its integer value.  */
69  int (*find_builtin) (const char *);
70
71  /* Make the given pointer use the given iterator value.  */
72  void (*apply_iterator) (void *, int);
73};
74
75/* Records one use of an iterator.  */
76struct iterator_use {
77  /* The iterator itself.  */
78  struct mapping *iterator;
79
80  /* The location of the use, as passed to the apply_iterator callback.  */
81  void *ptr;
82};
83
84/* Vector definitions for the above.  */
85typedef struct iterator_use iterator_use;
86
87/* Records one use of an attribute (the "<[iterator:]attribute>" syntax)
88   in a non-string rtx field.  */
89struct attribute_use {
90  /* The group that describes the use site.  */
91  struct iterator_group *group;
92
93  /* The name of the attribute, possibly with an "iterator:" prefix.  */
94  const char *value;
95
96  /* The location of the use, as passed to GROUP's apply_iterator callback.  */
97  void *ptr;
98};
99
100/* Vector definitions for the above.  */
101typedef struct attribute_use attribute_use;
102
103/* This struct is used to link subst_attr named ATTR_NAME with
104   corresponding define_subst named ITER_NAME.  */
105struct subst_attr_to_iter_mapping
106{
107    char *attr_name;
108    char *iter_name;
109};
110
111/* Hash-table to store links between subst-attributes and
112   define_substs.  */
113htab_t subst_attr_to_iter_map = NULL;
114/* This global stores name of subst-iterator which is currently being
115   processed.  */
116const char *current_iterator_name;
117
118static void validate_const_int (const char *);
119static rtx read_rtx_code (const char *);
120static rtx read_nested_rtx (void);
121static rtx read_rtx_variadic (rtx);
122
123/* The mode and code iterator structures.  */
124static struct iterator_group modes, codes, ints, substs;
125
126/* All iterators used in the current rtx.  */
127static vec<mapping_ptr> current_iterators;
128
129/* The list of all iterator uses in the current rtx.  */
130static vec<iterator_use> iterator_uses;
131
132/* The list of all attribute uses in the current rtx.  */
133static vec<attribute_use> attribute_uses;
134
135/* Implementations of the iterator_group callbacks for modes.  */
136
137static int
138find_mode (const char *name)
139{
140  int i;
141
142  for (i = 0; i < NUM_MACHINE_MODES; i++)
143    if (strcmp (GET_MODE_NAME (i), name) == 0)
144      return i;
145
146  fatal_with_file_and_line ("unknown mode `%s'", name);
147}
148
149static void
150apply_mode_iterator (void *loc, int mode)
151{
152  PUT_MODE ((rtx) loc, (machine_mode) mode);
153}
154
155/* Implementations of the iterator_group callbacks for codes.  */
156
157static int
158find_code (const char *name)
159{
160  int i;
161
162  for (i = 0; i < NUM_RTX_CODE; i++)
163    if (strcmp (GET_RTX_NAME (i), name) == 0)
164      return i;
165
166  fatal_with_file_and_line ("unknown rtx code `%s'", name);
167}
168
169static void
170apply_code_iterator (void *loc, int code)
171{
172  PUT_CODE ((rtx) loc, (enum rtx_code) code);
173}
174
175/* Implementations of the iterator_group callbacks for ints.  */
176
177/* Since GCC does not construct a table of valid constants,
178   we have to accept any int as valid.  No cross-checking can
179   be done.  */
180
181static int
182find_int (const char *name)
183{
184  validate_const_int (name);
185  return atoi (name);
186}
187
188static void
189apply_int_iterator (void *loc, int value)
190{
191  *(int *)loc = value;
192}
193
194/* This routine adds attribute or does nothing depending on VALUE.  When
195   VALUE is 1, it does nothing - the first duplicate of original
196   template is kept untouched when it's subjected to a define_subst.
197   When VALUE isn't 1, the routine modifies RTL-template LOC, adding
198   attribute, named exactly as define_subst, which later will be
199   applied.  If such attribute has already been added, then no the
200   routine has no effect.  */
201static void
202apply_subst_iterator (void *loc, int value)
203{
204  rtx rt = (rtx)loc;
205  rtx new_attr;
206  rtvec attrs_vec, new_attrs_vec;
207  int i;
208  if (value == 1)
209    return;
210  gcc_assert (GET_CODE (rt) == DEFINE_INSN
211	      || GET_CODE (rt) == DEFINE_EXPAND);
212
213  attrs_vec = XVEC (rt, 4);
214
215  /* If we've already added attribute 'current_iterator_name', then we
216     have nothing to do now.  */
217  if (attrs_vec)
218    {
219      for (i = 0; i < GET_NUM_ELEM (attrs_vec); i++)
220	{
221	  if (strcmp (XSTR (attrs_vec->elem[i], 0), current_iterator_name) == 0)
222	    return;
223	}
224    }
225
226  /* Add attribute with subst name - it serves as a mark for
227     define_subst which later would be applied to this pattern.  */
228  new_attr = rtx_alloc (SET_ATTR);
229  PUT_CODE (new_attr, SET_ATTR);
230  XSTR (new_attr, 0) = xstrdup (current_iterator_name);
231  XSTR (new_attr, 1) = xstrdup ("yes");
232
233  if (!attrs_vec)
234    {
235      new_attrs_vec = rtvec_alloc (1);
236      new_attrs_vec->elem[0] = new_attr;
237    }
238  else
239    {
240      new_attrs_vec = rtvec_alloc (GET_NUM_ELEM (attrs_vec) + 1);
241      memcpy (&new_attrs_vec->elem[0], &attrs_vec->elem[0],
242	      GET_NUM_ELEM (attrs_vec) * sizeof (rtx));
243      new_attrs_vec->elem[GET_NUM_ELEM (attrs_vec)] = new_attr;
244    }
245  XVEC (rt, 4) = new_attrs_vec;
246}
247
248/* Map subst-attribute ATTR to subst iterator ITER.  */
249
250static void
251bind_subst_iter_and_attr (const char *iter, const char *attr)
252{
253  struct subst_attr_to_iter_mapping *value;
254  void **slot;
255  if (!subst_attr_to_iter_map)
256    subst_attr_to_iter_map =
257      htab_create (1, leading_string_hash, leading_string_eq_p, 0);
258  value = XNEW (struct subst_attr_to_iter_mapping);
259  value->attr_name = xstrdup (attr);
260  value->iter_name = xstrdup (iter);
261  slot = htab_find_slot (subst_attr_to_iter_map, value, INSERT);
262  *slot = value;
263}
264
265/* Return name of a subst-iterator, corresponding to subst-attribute ATTR.  */
266
267static char*
268find_subst_iter_by_attr (const char *attr)
269{
270  char *iter_name = NULL;
271  struct subst_attr_to_iter_mapping *value;
272  value = (struct subst_attr_to_iter_mapping*)
273    htab_find (subst_attr_to_iter_map, &attr);
274  if (value)
275    iter_name = value->iter_name;
276  return iter_name;
277}
278
279/* Map attribute string P to its current value.  Return null if the attribute
280   isn't known.  */
281
282static struct map_value *
283map_attr_string (const char *p)
284{
285  const char *attr;
286  struct mapping *iterator;
287  unsigned int i;
288  struct mapping *m;
289  struct map_value *v;
290  int iterator_name_len;
291
292  /* Peel off any "iterator:" prefix.  Set ATTR to the start of the
293     attribute name.  */
294  attr = strchr (p, ':');
295  if (attr == 0)
296    {
297      iterator_name_len = -1;
298      attr = p;
299    }
300  else
301    {
302      iterator_name_len = attr - p;
303      attr++;
304    }
305
306  FOR_EACH_VEC_ELT (current_iterators, i, iterator)
307    {
308      /* If an iterator name was specified, check that it matches.  */
309      if (iterator_name_len >= 0
310	  && (strncmp (p, iterator->name, iterator_name_len) != 0
311	      || iterator->name[iterator_name_len] != 0))
312	continue;
313
314      /* Find the attribute specification.  */
315      m = (struct mapping *) htab_find (iterator->group->attrs, &attr);
316      if (m)
317	{
318	  /* In contrast to code/mode/int iterators, attributes of subst
319	     iterators are linked to one specific subst-iterator.  So, if
320	     we are dealing with subst-iterator, we should check if it's
321	     the one which linked with the given attribute.  */
322	  if (iterator->group == &substs)
323	    {
324	      char *iter_name = find_subst_iter_by_attr (attr);
325	      if (strcmp (iter_name, iterator->name) != 0)
326		continue;
327	    }
328	  /* Find the attribute value associated with the current
329	     iterator value.  */
330	  for (v = m->values; v; v = v->next)
331	    if (v->number == iterator->current_value->number)
332	      return v;
333	}
334    }
335  return NULL;
336}
337
338/* Apply the current iterator values to STRING.  Return the new string
339   if any changes were needed, otherwise return STRING itself.  */
340
341static const char *
342apply_iterator_to_string (const char *string)
343{
344  char *base, *copy, *p, *start, *end;
345  struct map_value *v;
346
347  if (string == 0)
348    return string;
349
350  base = p = copy = ASTRDUP (string);
351  while ((start = strchr (p, '<')) && (end = strchr (start, '>')))
352    {
353      p = start + 1;
354
355      *end = 0;
356      v = map_attr_string (p);
357      *end = '>';
358      if (v == 0)
359	continue;
360
361      /* Add everything between the last copied byte and the '<',
362	 then add in the attribute value.  */
363      obstack_grow (&string_obstack, base, start - base);
364      obstack_grow (&string_obstack, v->string, strlen (v->string));
365      base = end + 1;
366    }
367  if (base != copy)
368    {
369      obstack_grow (&string_obstack, base, strlen (base) + 1);
370      copy = XOBFINISH (&string_obstack, char *);
371      copy_md_ptr_loc (copy, string);
372      return copy;
373    }
374  return string;
375}
376
377/* Return a deep copy of X, substituting the current iterator
378   values into any strings.  */
379
380static rtx
381copy_rtx_for_iterators (rtx original)
382{
383  const char *format_ptr, *p;
384  int i, j;
385  rtx x;
386
387  if (original == 0)
388    return original;
389
390  /* Create a shallow copy of ORIGINAL.  */
391  x = rtx_alloc (GET_CODE (original));
392  memcpy (x, original, RTX_CODE_SIZE (GET_CODE (original)));
393
394  /* Change each string and recursively change each rtx.  */
395  format_ptr = GET_RTX_FORMAT (GET_CODE (original));
396  for (i = 0; format_ptr[i] != 0; i++)
397    switch (format_ptr[i])
398      {
399      case 'T':
400	while (XTMPL (x, i) != (p = apply_iterator_to_string (XTMPL (x, i))))
401	  XTMPL (x, i) = p;
402	break;
403
404      case 'S':
405      case 's':
406	while (XSTR (x, i) != (p = apply_iterator_to_string (XSTR (x, i))))
407	  XSTR (x, i) = p;
408	break;
409
410      case 'e':
411	XEXP (x, i) = copy_rtx_for_iterators (XEXP (x, i));
412	break;
413
414      case 'V':
415      case 'E':
416	if (XVEC (original, i))
417	  {
418	    XVEC (x, i) = rtvec_alloc (XVECLEN (original, i));
419	    for (j = 0; j < XVECLEN (x, i); j++)
420	      XVECEXP (x, i, j)
421		= copy_rtx_for_iterators (XVECEXP (original, i, j));
422	  }
423	break;
424
425      default:
426	break;
427      }
428  return x;
429}
430
431/* Return a condition that must satisfy both ORIGINAL and EXTRA.  If ORIGINAL
432   has the form "&& ..." (as used in define_insn_and_splits), assume that
433   EXTRA is already satisfied.  Empty strings are treated like "true".  */
434
435static const char *
436add_condition_to_string (const char *original, const char *extra)
437{
438  if (original != 0 && original[0] == '&' && original[1] == '&')
439    return original;
440  return join_c_conditions (original, extra);
441}
442
443/* Like add_condition, but applied to all conditions in rtx X.  */
444
445static void
446add_condition_to_rtx (rtx x, const char *extra)
447{
448  switch (GET_CODE (x))
449    {
450    case DEFINE_INSN:
451    case DEFINE_EXPAND:
452    case DEFINE_SUBST:
453      XSTR (x, 2) = add_condition_to_string (XSTR (x, 2), extra);
454      break;
455
456    case DEFINE_SPLIT:
457    case DEFINE_PEEPHOLE:
458    case DEFINE_PEEPHOLE2:
459    case DEFINE_COND_EXEC:
460      XSTR (x, 1) = add_condition_to_string (XSTR (x, 1), extra);
461      break;
462
463    case DEFINE_INSN_AND_SPLIT:
464      XSTR (x, 2) = add_condition_to_string (XSTR (x, 2), extra);
465      XSTR (x, 4) = add_condition_to_string (XSTR (x, 4), extra);
466      break;
467
468    default:
469      break;
470    }
471}
472
473/* Apply the current iterator values to all attribute_uses.  */
474
475static void
476apply_attribute_uses (void)
477{
478  struct map_value *v;
479  attribute_use *ause;
480  unsigned int i;
481
482  FOR_EACH_VEC_ELT (attribute_uses, i, ause)
483    {
484      v = map_attr_string (ause->value);
485      if (!v)
486	fatal_with_file_and_line ("unknown iterator value `%s'", ause->value);
487      ause->group->apply_iterator (ause->ptr,
488				   ause->group->find_builtin (v->string));
489    }
490}
491
492/* A htab_traverse callback for iterators.  Add all used iterators
493   to current_iterators.  */
494
495static int
496add_current_iterators (void **slot, void *data ATTRIBUTE_UNUSED)
497{
498  struct mapping *iterator;
499
500  iterator = (struct mapping *) *slot;
501  if (iterator->current_value)
502    current_iterators.safe_push (iterator);
503  return 1;
504}
505
506/* Expand all iterators in the current rtx, which is given as ORIGINAL.
507   Build a list of expanded rtxes in the EXPR_LIST pointed to by QUEUE.  */
508
509static void
510apply_iterators (rtx original, rtx *queue)
511{
512  unsigned int i;
513  const char *condition;
514  iterator_use *iuse;
515  struct mapping *iterator;
516  struct map_value *v;
517  rtx x;
518
519  if (iterator_uses.is_empty ())
520    {
521      /* Raise an error if any attributes were used.  */
522      apply_attribute_uses ();
523      XEXP (*queue, 0) = original;
524      XEXP (*queue, 1) = NULL_RTX;
525      return;
526    }
527
528  /* Clear out the iterators from the previous run.  */
529  FOR_EACH_VEC_ELT (current_iterators, i, iterator)
530    iterator->current_value = NULL;
531  current_iterators.truncate (0);
532
533  /* Mark the iterators that we need this time.  */
534  FOR_EACH_VEC_ELT (iterator_uses, i, iuse)
535    iuse->iterator->current_value = iuse->iterator->values;
536
537  /* Get the list of iterators that are in use, preserving the
538     definition order within each group.  */
539  htab_traverse (modes.iterators, add_current_iterators, NULL);
540  htab_traverse (codes.iterators, add_current_iterators, NULL);
541  htab_traverse (ints.iterators, add_current_iterators, NULL);
542  htab_traverse (substs.iterators, add_current_iterators, NULL);
543  gcc_assert (!current_iterators.is_empty ());
544
545  for (;;)
546    {
547      /* Apply the current iterator values.  Accumulate a condition to
548	 say when the resulting rtx can be used.  */
549      condition = "";
550      FOR_EACH_VEC_ELT (iterator_uses, i, iuse)
551	{
552	  if (iuse->iterator->group == &substs)
553	    continue;
554	  v = iuse->iterator->current_value;
555	  iuse->iterator->group->apply_iterator (iuse->ptr, v->number);
556	  condition = join_c_conditions (condition, v->string);
557	}
558      apply_attribute_uses ();
559      x = copy_rtx_for_iterators (original);
560      add_condition_to_rtx (x, condition);
561
562      /* We apply subst iterator after RTL-template is copied, as during
563	 subst-iterator processing, we could add an attribute to the
564	 RTL-template, and we don't want to do it in the original one.  */
565      FOR_EACH_VEC_ELT (iterator_uses, i, iuse)
566	{
567	  v = iuse->iterator->current_value;
568	  if (iuse->iterator->group == &substs)
569	    {
570	      iuse->ptr = x;
571	      current_iterator_name = iuse->iterator->name;
572	      iuse->iterator->group->apply_iterator (iuse->ptr, v->number);
573	    }
574	}
575      /* Add the new rtx to the end of the queue.  */
576      XEXP (*queue, 0) = x;
577      XEXP (*queue, 1) = NULL_RTX;
578
579      /* Lexicographically increment the iterator value sequence.
580	 That is, cycle through iterator values, starting from the right,
581	 and stopping when one of them doesn't wrap around.  */
582      i = current_iterators.length ();
583      for (;;)
584	{
585	  if (i == 0)
586	    return;
587	  i--;
588	  iterator = current_iterators[i];
589	  iterator->current_value = iterator->current_value->next;
590	  if (iterator->current_value)
591	    break;
592	  iterator->current_value = iterator->values;
593	}
594
595      /* At least one more rtx to go.  Allocate room for it.  */
596      XEXP (*queue, 1) = rtx_alloc (EXPR_LIST);
597      queue = &XEXP (*queue, 1);
598    }
599}
600
601/* Add a new "mapping" structure to hashtable TABLE.  NAME is the name
602   of the mapping and GROUP is the group to which it belongs.  */
603
604static struct mapping *
605add_mapping (struct iterator_group *group, htab_t table, const char *name)
606{
607  struct mapping *m;
608  void **slot;
609
610  m = XNEW (struct mapping);
611  m->name = xstrdup (name);
612  m->group = group;
613  m->values = 0;
614  m->current_value = NULL;
615
616  slot = htab_find_slot (table, m, INSERT);
617  if (*slot != 0)
618    fatal_with_file_and_line ("`%s' already defined", name);
619
620  *slot = m;
621  return m;
622}
623
624/* Add the pair (NUMBER, STRING) to a list of map_value structures.
625   END_PTR points to the current null terminator for the list; return
626   a pointer the new null terminator.  */
627
628static struct map_value **
629add_map_value (struct map_value **end_ptr, int number, const char *string)
630{
631  struct map_value *value;
632
633  value = XNEW (struct map_value);
634  value->next = 0;
635  value->number = number;
636  value->string = string;
637
638  *end_ptr = value;
639  return &value->next;
640}
641
642/* Do one-time initialization of the mode and code attributes.  */
643
644static void
645initialize_iterators (void)
646{
647  struct mapping *lower, *upper;
648  struct map_value **lower_ptr, **upper_ptr;
649  char *copy, *p;
650  int i;
651
652  modes.attrs = htab_create (13, leading_string_hash, leading_string_eq_p, 0);
653  modes.iterators = htab_create (13, leading_string_hash,
654				 leading_string_eq_p, 0);
655  modes.find_builtin = find_mode;
656  modes.apply_iterator = apply_mode_iterator;
657
658  codes.attrs = htab_create (13, leading_string_hash, leading_string_eq_p, 0);
659  codes.iterators = htab_create (13, leading_string_hash,
660				 leading_string_eq_p, 0);
661  codes.find_builtin = find_code;
662  codes.apply_iterator = apply_code_iterator;
663
664  ints.attrs = htab_create (13, leading_string_hash, leading_string_eq_p, 0);
665  ints.iterators = htab_create (13, leading_string_hash,
666				 leading_string_eq_p, 0);
667  ints.find_builtin = find_int;
668  ints.apply_iterator = apply_int_iterator;
669
670  substs.attrs = htab_create (13, leading_string_hash, leading_string_eq_p, 0);
671  substs.iterators = htab_create (13, leading_string_hash,
672				 leading_string_eq_p, 0);
673  substs.find_builtin = find_int; /* We don't use it, anyway.  */
674  substs.apply_iterator = apply_subst_iterator;
675
676  lower = add_mapping (&modes, modes.attrs, "mode");
677  upper = add_mapping (&modes, modes.attrs, "MODE");
678  lower_ptr = &lower->values;
679  upper_ptr = &upper->values;
680  for (i = 0; i < MAX_MACHINE_MODE; i++)
681    {
682      copy = xstrdup (GET_MODE_NAME (i));
683      for (p = copy; *p != 0; p++)
684	*p = TOLOWER (*p);
685
686      upper_ptr = add_map_value (upper_ptr, i, GET_MODE_NAME (i));
687      lower_ptr = add_map_value (lower_ptr, i, copy);
688    }
689
690  lower = add_mapping (&codes, codes.attrs, "code");
691  upper = add_mapping (&codes, codes.attrs, "CODE");
692  lower_ptr = &lower->values;
693  upper_ptr = &upper->values;
694  for (i = 0; i < NUM_RTX_CODE; i++)
695    {
696      copy = xstrdup (GET_RTX_NAME (i));
697      for (p = copy; *p != 0; p++)
698	*p = TOUPPER (*p);
699
700      lower_ptr = add_map_value (lower_ptr, i, GET_RTX_NAME (i));
701      upper_ptr = add_map_value (upper_ptr, i, copy);
702    }
703}
704
705/* Provide a version of a function to read a long long if the system does
706   not provide one.  */
707#if HOST_BITS_PER_WIDE_INT > HOST_BITS_PER_LONG && !defined(HAVE_ATOLL) && !defined(HAVE_ATOQ)
708HOST_WIDE_INT atoll (const char *);
709
710HOST_WIDE_INT
711atoll (const char *p)
712{
713  int neg = 0;
714  HOST_WIDE_INT tmp_wide;
715
716  while (ISSPACE (*p))
717    p++;
718  if (*p == '-')
719    neg = 1, p++;
720  else if (*p == '+')
721    p++;
722
723  tmp_wide = 0;
724  while (ISDIGIT (*p))
725    {
726      HOST_WIDE_INT new_wide = tmp_wide*10 + (*p - '0');
727      if (new_wide < tmp_wide)
728	{
729	  /* Return INT_MAX equiv on overflow.  */
730	  tmp_wide = (~(unsigned HOST_WIDE_INT) 0) >> 1;
731	  break;
732	}
733      tmp_wide = new_wide;
734      p++;
735    }
736
737  if (neg)
738    tmp_wide = -tmp_wide;
739  return tmp_wide;
740}
741#endif
742
743/* Process a define_conditions directive, starting with the optional
744   space after the "define_conditions".  The directive looks like this:
745
746     (define_conditions [
747        (number "string")
748        (number "string")
749        ...
750     ])
751
752   It's not intended to appear in machine descriptions.  It is
753   generated by (the program generated by) genconditions.c, and
754   slipped in at the beginning of the sequence of MD files read by
755   most of the other generators.  */
756static void
757read_conditions (void)
758{
759  int c;
760
761  c = read_skip_spaces ();
762  if (c != '[')
763    fatal_expected_char ('[', c);
764
765  while ( (c = read_skip_spaces ()) != ']')
766    {
767      struct md_name name;
768      char *expr;
769      int value;
770
771      if (c != '(')
772	fatal_expected_char ('(', c);
773
774      read_name (&name);
775      validate_const_int (name.string);
776      value = atoi (name.string);
777
778      c = read_skip_spaces ();
779      if (c != '"')
780	fatal_expected_char ('"', c);
781      expr = read_quoted_string ();
782
783      c = read_skip_spaces ();
784      if (c != ')')
785	fatal_expected_char (')', c);
786
787      add_c_test (expr, value);
788    }
789}
790
791static void
792validate_const_int (const char *string)
793{
794  const char *cp;
795  int valid = 1;
796
797  cp = string;
798  while (*cp && ISSPACE (*cp))
799    cp++;
800  if (*cp == '-' || *cp == '+')
801    cp++;
802  if (*cp == 0)
803    valid = 0;
804  for (; *cp; cp++)
805    if (! ISDIGIT (*cp))
806      {
807        valid = 0;
808	break;
809      }
810  if (!valid)
811    fatal_with_file_and_line ("invalid decimal constant \"%s\"\n", string);
812}
813
814static void
815validate_const_wide_int (const char *string)
816{
817  const char *cp;
818  int valid = 1;
819
820  cp = string;
821  while (*cp && ISSPACE (*cp))
822    cp++;
823  /* Skip the leading 0x.  */
824  if (cp[0] == '0' || cp[1] == 'x')
825    cp += 2;
826  else
827    valid = 0;
828  if (*cp == 0)
829    valid = 0;
830  for (; *cp; cp++)
831    if (! ISXDIGIT (*cp))
832      valid = 0;
833  if (!valid)
834    fatal_with_file_and_line ("invalid hex constant \"%s\"\n", string);
835}
836
837/* Record that PTR uses iterator ITERATOR.  */
838
839static void
840record_iterator_use (struct mapping *iterator, void *ptr)
841{
842  struct iterator_use iuse = {iterator, ptr};
843  iterator_uses.safe_push (iuse);
844}
845
846/* Record that PTR uses attribute VALUE, which must match a built-in
847   value from group GROUP.  */
848
849static void
850record_attribute_use (struct iterator_group *group, void *ptr,
851		      const char *value)
852{
853  struct attribute_use ause = {group, value, ptr};
854  attribute_uses.safe_push (ause);
855}
856
857/* Interpret NAME as either a built-in value, iterator or attribute
858   for group GROUP.  PTR is the value to pass to GROUP's apply_iterator
859   callback.  */
860
861static void
862record_potential_iterator_use (struct iterator_group *group, void *ptr,
863			       const char *name)
864{
865  struct mapping *m;
866  size_t len;
867
868  len = strlen (name);
869  if (name[0] == '<' && name[len - 1] == '>')
870    {
871      /* Copy the attribute string into permanent storage, without the
872	 angle brackets around it.  */
873      obstack_grow0 (&string_obstack, name + 1, len - 2);
874      record_attribute_use (group, ptr, XOBFINISH (&string_obstack, char *));
875    }
876  else
877    {
878      m = (struct mapping *) htab_find (group->iterators, &name);
879      if (m != 0)
880	record_iterator_use (m, ptr);
881      else
882	group->apply_iterator (ptr, group->find_builtin (name));
883    }
884}
885
886/* Finish reading a declaration of the form:
887
888       (define... <name> [<value1> ... <valuen>])
889
890   from the MD file, where each <valuei> is either a bare symbol name or a
891   "(<name> <string>)" pair.  The "(define..." part has already been read.
892
893   Represent the declaration as a "mapping" structure; add it to TABLE
894   (which belongs to GROUP) and return it.  */
895
896static struct mapping *
897read_mapping (struct iterator_group *group, htab_t table)
898{
899  struct md_name name;
900  struct mapping *m;
901  struct map_value **end_ptr;
902  const char *string;
903  int number, c;
904
905  /* Read the mapping name and create a structure for it.  */
906  read_name (&name);
907  m = add_mapping (group, table, name.string);
908
909  c = read_skip_spaces ();
910  if (c != '[')
911    fatal_expected_char ('[', c);
912
913  /* Read each value.  */
914  end_ptr = &m->values;
915  c = read_skip_spaces ();
916  do
917    {
918      if (c != '(')
919	{
920	  /* A bare symbol name that is implicitly paired to an
921	     empty string.  */
922	  unread_char (c);
923	  read_name (&name);
924	  string = "";
925	}
926      else
927	{
928	  /* A "(name string)" pair.  */
929	  read_name (&name);
930	  string = read_string (false);
931	  c = read_skip_spaces ();
932	  if (c != ')')
933	    fatal_expected_char (')', c);
934	}
935      number = group->find_builtin (name.string);
936      end_ptr = add_map_value (end_ptr, number, string);
937      c = read_skip_spaces ();
938    }
939  while (c != ']');
940
941  return m;
942}
943
944/* For iterator with name ATTR_NAME generate define_attr with values
945   'yes' and 'no'.  This attribute is used to mark templates to which
946   define_subst ATTR_NAME should be applied.  This attribute is set and
947   defined implicitly and automatically.  */
948static void
949add_define_attr_for_define_subst (const char *attr_name, rtx *queue)
950{
951  rtx const_str, return_rtx;
952
953  return_rtx = rtx_alloc (DEFINE_ATTR);
954  PUT_CODE (return_rtx, DEFINE_ATTR);
955
956  const_str = rtx_alloc (CONST_STRING);
957  PUT_CODE (const_str, CONST_STRING);
958  XSTR (const_str, 0) = xstrdup ("no");
959
960  XSTR (return_rtx, 0) = xstrdup (attr_name);
961  XSTR (return_rtx, 1) = xstrdup ("no,yes");
962  XEXP (return_rtx, 2) = const_str;
963
964  XEXP (*queue, 0) = return_rtx;
965  XEXP (*queue, 1) = NULL_RTX;
966}
967
968/* This routine generates DEFINE_SUBST_ATTR expression with operands
969   ATTR_OPERANDS and places it to QUEUE.  */
970static void
971add_define_subst_attr (const char **attr_operands, rtx *queue)
972{
973  rtx return_rtx;
974  int i;
975
976  return_rtx = rtx_alloc (DEFINE_SUBST_ATTR);
977  PUT_CODE (return_rtx, DEFINE_SUBST_ATTR);
978
979  for (i = 0; i < 4; i++)
980    XSTR (return_rtx, i) = xstrdup (attr_operands[i]);
981
982  XEXP (*queue, 0) = return_rtx;
983  XEXP (*queue, 1) = NULL_RTX;
984}
985
986/* Read define_subst_attribute construction.  It has next form:
987	(define_subst_attribute <attribute_name> <iterator_name> <value1> <value2>)
988   Attribute is substituted with value1 when no subst is applied and with
989   value2 in the opposite case.
990   Attributes are added to SUBST_ATTRS_TABLE.
991   In case the iterator is encountered for the first time, it's added to
992   SUBST_ITERS_TABLE.  Also, implicit define_attr is generated.  */
993
994static void
995read_subst_mapping (htab_t subst_iters_table, htab_t subst_attrs_table,
996		    rtx *queue)
997{
998  struct mapping *m;
999  struct map_value **end_ptr;
1000  const char *attr_operands[4];
1001  rtx * queue_elem = queue;
1002  int i;
1003
1004  for (i = 0; i < 4; i++)
1005    attr_operands[i] = read_string (false);
1006
1007  add_define_subst_attr (attr_operands, queue_elem);
1008
1009  bind_subst_iter_and_attr (attr_operands[1], attr_operands[0]);
1010
1011  m = (struct mapping *) htab_find (substs.iterators, &attr_operands[1]);
1012  if (!m)
1013    {
1014      m = add_mapping (&substs, subst_iters_table, attr_operands[1]);
1015      end_ptr = &m->values;
1016      end_ptr = add_map_value (end_ptr, 1, "");
1017      end_ptr = add_map_value (end_ptr, 2, "");
1018
1019      /* Add element to the queue.  */
1020      XEXP (*queue, 1) = rtx_alloc (EXPR_LIST);
1021      queue_elem = &XEXP (*queue, 1);
1022
1023      add_define_attr_for_define_subst (attr_operands[1], queue_elem);
1024    }
1025
1026  m = add_mapping (&substs, subst_attrs_table, attr_operands[0]);
1027  end_ptr = &m->values;
1028  end_ptr = add_map_value (end_ptr, 1, attr_operands[2]);
1029  end_ptr = add_map_value (end_ptr, 2, attr_operands[3]);
1030}
1031
1032/* Check newly-created code iterator ITERATOR to see whether every code has the
1033   same format.  */
1034
1035static void
1036check_code_iterator (struct mapping *iterator)
1037{
1038  struct map_value *v;
1039  enum rtx_code bellwether;
1040
1041  bellwether = (enum rtx_code) iterator->values->number;
1042  for (v = iterator->values->next; v != 0; v = v->next)
1043    if (strcmp (GET_RTX_FORMAT (bellwether), GET_RTX_FORMAT (v->number)) != 0)
1044      fatal_with_file_and_line ("code iterator `%s' combines "
1045				"different rtx formats", iterator->name);
1046}
1047
1048/* Read an rtx-related declaration from the MD file, given that it
1049   starts with directive name RTX_NAME.  Return true if it expands to
1050   one or more rtxes (as defined by rtx.def).  When returning true,
1051   store the list of rtxes as an EXPR_LIST in *X.  */
1052
1053bool
1054read_rtx (const char *rtx_name, rtx *x)
1055{
1056  static rtx queue_head;
1057
1058  /* Do one-time initialization.  */
1059  if (queue_head == 0)
1060    {
1061      initialize_iterators ();
1062      queue_head = rtx_alloc (EXPR_LIST);
1063    }
1064
1065  /* Handle various rtx-related declarations that aren't themselves
1066     encoded as rtxes.  */
1067  if (strcmp (rtx_name, "define_conditions") == 0)
1068    {
1069      read_conditions ();
1070      return false;
1071    }
1072  if (strcmp (rtx_name, "define_mode_attr") == 0)
1073    {
1074      read_mapping (&modes, modes.attrs);
1075      return false;
1076    }
1077  if (strcmp (rtx_name, "define_mode_iterator") == 0)
1078    {
1079      read_mapping (&modes, modes.iterators);
1080      return false;
1081    }
1082  if (strcmp (rtx_name, "define_code_attr") == 0)
1083    {
1084      read_mapping (&codes, codes.attrs);
1085      return false;
1086    }
1087  if (strcmp (rtx_name, "define_code_iterator") == 0)
1088    {
1089      check_code_iterator (read_mapping (&codes, codes.iterators));
1090      return false;
1091    }
1092  if (strcmp (rtx_name, "define_int_attr") == 0)
1093    {
1094      read_mapping (&ints, ints.attrs);
1095      return false;
1096    }
1097  if (strcmp (rtx_name, "define_int_iterator") == 0)
1098    {
1099      read_mapping (&ints, ints.iterators);
1100      return false;
1101    }
1102  if (strcmp (rtx_name, "define_subst_attr") == 0)
1103    {
1104      read_subst_mapping (substs.iterators, substs.attrs, &queue_head);
1105      *x = queue_head;
1106
1107      /* READ_SUBST_MAPPING could generate a new DEFINE_ATTR.  Return
1108	 TRUE to process it.  */
1109      return true;
1110    }
1111
1112  apply_iterators (read_rtx_code (rtx_name), &queue_head);
1113  iterator_uses.truncate (0);
1114  attribute_uses.truncate (0);
1115
1116  *x = queue_head;
1117  return true;
1118}
1119
1120/* Subroutine of read_rtx and read_nested_rtx.  CODE_NAME is the name of
1121   either an rtx code or a code iterator.  Parse the rest of the rtx and
1122   return it.  */
1123
1124static rtx
1125read_rtx_code (const char *code_name)
1126{
1127  int i;
1128  RTX_CODE code;
1129  struct mapping *iterator, *m;
1130  const char *format_ptr;
1131  struct md_name name;
1132  rtx return_rtx;
1133  int c;
1134  HOST_WIDE_INT tmp_wide;
1135  char *str;
1136  char *start, *end, *ptr;
1137  char tmpstr[256];
1138
1139  /* Linked list structure for making RTXs: */
1140  struct rtx_list
1141    {
1142      struct rtx_list *next;
1143      rtx value;		/* Value of this node.  */
1144    };
1145
1146  /* If this code is an iterator, build the rtx using the iterator's
1147     first value.  */
1148  iterator = (struct mapping *) htab_find (codes.iterators, &code_name);
1149  if (iterator != 0)
1150    code = (enum rtx_code) iterator->values->number;
1151  else
1152    code = (enum rtx_code) codes.find_builtin (code_name);
1153
1154  /* If we end up with an insn expression then we free this space below.  */
1155  return_rtx = rtx_alloc (code);
1156  format_ptr = GET_RTX_FORMAT (code);
1157  memset (return_rtx, 0, RTX_CODE_SIZE (code));
1158  PUT_CODE (return_rtx, code);
1159
1160  if (iterator)
1161    record_iterator_use (iterator, return_rtx);
1162
1163  /* If what follows is `: mode ', read it and
1164     store the mode in the rtx.  */
1165
1166  i = read_skip_spaces ();
1167  if (i == ':')
1168    {
1169      read_name (&name);
1170      record_potential_iterator_use (&modes, return_rtx, name.string);
1171    }
1172  else
1173    unread_char (i);
1174
1175  for (i = 0; format_ptr[i] != 0; i++)
1176    switch (format_ptr[i])
1177      {
1178	/* 0 means a field for internal use only.
1179	   Don't expect it to be present in the input.  */
1180      case '0':
1181	if (code == REG)
1182	  ORIGINAL_REGNO (return_rtx) = REGNO (return_rtx);
1183	break;
1184
1185      case 'e':
1186      case 'u':
1187	XEXP (return_rtx, i) = read_nested_rtx ();
1188	break;
1189
1190      case 'V':
1191	/* 'V' is an optional vector: if a closeparen follows,
1192	   just store NULL for this element.  */
1193	c = read_skip_spaces ();
1194	unread_char (c);
1195	if (c == ')')
1196	  {
1197	    XVEC (return_rtx, i) = 0;
1198	    break;
1199	  }
1200	/* Now process the vector.  */
1201
1202      case 'E':
1203	{
1204	  /* Obstack to store scratch vector in.  */
1205	  struct obstack vector_stack;
1206	  int list_counter = 0;
1207	  rtvec return_vec = NULL_RTVEC;
1208
1209	  c = read_skip_spaces ();
1210	  if (c != '[')
1211	    fatal_expected_char ('[', c);
1212
1213	  /* Add expressions to a list, while keeping a count.  */
1214	  obstack_init (&vector_stack);
1215	  while ((c = read_skip_spaces ()) && c != ']')
1216	    {
1217	      if (c == EOF)
1218		fatal_expected_char (']', c);
1219	      unread_char (c);
1220	      list_counter++;
1221	      obstack_ptr_grow (&vector_stack, read_nested_rtx ());
1222	    }
1223	  if (list_counter > 0)
1224	    {
1225	      return_vec = rtvec_alloc (list_counter);
1226	      memcpy (&return_vec->elem[0], obstack_finish (&vector_stack),
1227		      list_counter * sizeof (rtx));
1228	    }
1229	  else if (format_ptr[i] == 'E')
1230	    fatal_with_file_and_line ("vector must have at least one element");
1231	  XVEC (return_rtx, i) = return_vec;
1232	  obstack_free (&vector_stack, NULL);
1233	  /* close bracket gotten */
1234	}
1235	break;
1236
1237      case 'S':
1238      case 'T':
1239      case 's':
1240	{
1241	  char *stringbuf;
1242	  int star_if_braced;
1243
1244	  c = read_skip_spaces ();
1245	  unread_char (c);
1246	  if (c == ')')
1247	    {
1248	      /* 'S' fields are optional and should be NULL if no string
1249		 was given.  Also allow normal 's' and 'T' strings to be
1250		 omitted, treating them in the same way as empty strings.  */
1251	      XSTR (return_rtx, i) = (format_ptr[i] == 'S' ? NULL : "");
1252	      break;
1253	    }
1254
1255	  /* The output template slot of a DEFINE_INSN,
1256	     DEFINE_INSN_AND_SPLIT, or DEFINE_PEEPHOLE automatically
1257	     gets a star inserted as its first character, if it is
1258	     written with a brace block instead of a string constant.  */
1259	  star_if_braced = (format_ptr[i] == 'T');
1260
1261	  stringbuf = read_string (star_if_braced);
1262
1263	  /* For insn patterns, we want to provide a default name
1264	     based on the file and line, like "*foo.md:12", if the
1265	     given name is blank.  These are only for define_insn and
1266	     define_insn_and_split, to aid debugging.  */
1267	  if (*stringbuf == '\0'
1268	      && i == 0
1269	      && (GET_CODE (return_rtx) == DEFINE_INSN
1270		  || GET_CODE (return_rtx) == DEFINE_INSN_AND_SPLIT))
1271	    {
1272	      char line_name[20];
1273	      const char *fn = (read_md_filename ? read_md_filename : "rtx");
1274	      const char *slash;
1275	      for (slash = fn; *slash; slash ++)
1276		if (*slash == '/' || *slash == '\\' || *slash == ':')
1277		  fn = slash + 1;
1278	      obstack_1grow (&string_obstack, '*');
1279	      obstack_grow (&string_obstack, fn, strlen (fn));
1280	      sprintf (line_name, ":%d", read_md_lineno);
1281	      obstack_grow (&string_obstack, line_name, strlen (line_name)+1);
1282	      stringbuf = XOBFINISH (&string_obstack, char *);
1283	    }
1284
1285	  /* Find attr-names in the string.  */
1286	  ptr = &tmpstr[0];
1287	  end = stringbuf;
1288	  while ((start = strchr (end, '<')) && (end  = strchr (start, '>')))
1289	    {
1290	      if ((end - start - 1 > 0)
1291		  && (end - start - 1 < (int)sizeof (tmpstr)))
1292		{
1293		  strncpy (tmpstr, start+1, end-start-1);
1294		  tmpstr[end-start-1] = 0;
1295		  end++;
1296		}
1297	      else
1298		break;
1299	      m = (struct mapping *) htab_find (substs.attrs, &ptr);
1300	      if (m != 0)
1301		{
1302		  /* Here we should find linked subst-iter.  */
1303		  str = find_subst_iter_by_attr (ptr);
1304		  if (str)
1305		    m = (struct mapping *) htab_find (substs.iterators, &str);
1306		  else
1307		    m = 0;
1308		}
1309	      if (m != 0)
1310		record_iterator_use (m, return_rtx);
1311	    }
1312
1313	  if (star_if_braced)
1314	    XTMPL (return_rtx, i) = stringbuf;
1315	  else
1316	    XSTR (return_rtx, i) = stringbuf;
1317	}
1318	break;
1319
1320      case 'w':
1321	read_name (&name);
1322	validate_const_int (name.string);
1323#if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_INT
1324	tmp_wide = atoi (name.string);
1325#else
1326#if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_LONG
1327	tmp_wide = atol (name.string);
1328#else
1329	/* Prefer atoll over atoq, since the former is in the ISO C99 standard.
1330	   But prefer not to use our hand-rolled function above either.  */
1331#if defined(HAVE_ATOLL) || !defined(HAVE_ATOQ)
1332	tmp_wide = atoll (name.string);
1333#else
1334	tmp_wide = atoq (name.string);
1335#endif
1336#endif
1337#endif
1338	XWINT (return_rtx, i) = tmp_wide;
1339	break;
1340
1341      case 'i':
1342      case 'n':
1343	/* Can be an iterator or an integer constant.  */
1344	read_name (&name);
1345	record_potential_iterator_use (&ints, &XINT (return_rtx, i),
1346				       name.string);
1347	break;
1348
1349      default:
1350	gcc_unreachable ();
1351      }
1352
1353  if (CONST_WIDE_INT_P (return_rtx))
1354    {
1355      read_name (&name);
1356      validate_const_wide_int (name.string);
1357      {
1358	const char *s = name.string;
1359	int len;
1360	int index = 0;
1361	int gs = HOST_BITS_PER_WIDE_INT/4;
1362	int pos;
1363	char * buf = XALLOCAVEC (char, gs + 1);
1364	unsigned HOST_WIDE_INT wi;
1365	int wlen;
1366
1367	/* Skip the leading spaces.  */
1368	while (*s && ISSPACE (*s))
1369	  s++;
1370
1371	/* Skip the leading 0x.  */
1372	gcc_assert (s[0] == '0');
1373	gcc_assert (s[1] == 'x');
1374	s += 2;
1375
1376	len = strlen (s);
1377	pos = len - gs;
1378	wlen = (len + gs - 1) / gs;	/* Number of words needed */
1379
1380	return_rtx = const_wide_int_alloc (wlen);
1381
1382	while (pos > 0)
1383	  {
1384#if HOST_BITS_PER_WIDE_INT == 64
1385	    sscanf (s + pos, "%16" HOST_WIDE_INT_PRINT "x", &wi);
1386#else
1387	    sscanf (s + pos, "%8" HOST_WIDE_INT_PRINT "x", &wi);
1388#endif
1389	    CWI_ELT (return_rtx, index++) = wi;
1390	    pos -= gs;
1391	  }
1392	strncpy (buf, s, gs - pos);
1393	buf [gs - pos] = 0;
1394	sscanf (buf, "%" HOST_WIDE_INT_PRINT "x", &wi);
1395	CWI_ELT (return_rtx, index++) = wi;
1396	/* TODO: After reading, do we want to canonicalize with:
1397	   value = lookup_const_wide_int (value); ? */
1398      }
1399    }
1400
1401  c = read_skip_spaces ();
1402  /* Syntactic sugar for AND and IOR, allowing Lisp-like
1403     arbitrary number of arguments for them.  */
1404  if (c == '('
1405      && (GET_CODE (return_rtx) == AND
1406	  || GET_CODE (return_rtx) == IOR))
1407    return read_rtx_variadic (return_rtx);
1408
1409  unread_char (c);
1410  return return_rtx;
1411}
1412
1413/* Read a nested rtx construct from the MD file and return it.  */
1414
1415static rtx
1416read_nested_rtx (void)
1417{
1418  struct md_name name;
1419  int c;
1420  rtx return_rtx;
1421
1422  c = read_skip_spaces ();
1423  if (c != '(')
1424    fatal_expected_char ('(', c);
1425
1426  read_name (&name);
1427  if (strcmp (name.string, "nil") == 0)
1428    return_rtx = NULL;
1429  else
1430    return_rtx = read_rtx_code (name.string);
1431
1432  c = read_skip_spaces ();
1433  if (c != ')')
1434    fatal_expected_char (')', c);
1435
1436  return return_rtx;
1437}
1438
1439/* Mutually recursive subroutine of read_rtx which reads
1440   (thing x1 x2 x3 ...) and produces RTL as if
1441   (thing x1 (thing x2 (thing x3 ...)))  had been written.
1442   When called, FORM is (thing x1 x2), and the file position
1443   is just past the leading parenthesis of x3.  Only works
1444   for THINGs which are dyadic expressions, e.g. AND, IOR.  */
1445static rtx
1446read_rtx_variadic (rtx form)
1447{
1448  char c = '(';
1449  rtx p = form, q;
1450
1451  do
1452    {
1453      unread_char (c);
1454
1455      q = rtx_alloc (GET_CODE (p));
1456      PUT_MODE (q, GET_MODE (p));
1457
1458      XEXP (q, 0) = XEXP (p, 1);
1459      XEXP (q, 1) = read_nested_rtx ();
1460
1461      XEXP (p, 1) = q;
1462      p = q;
1463      c = read_skip_spaces ();
1464    }
1465  while (c == '(');
1466  unread_char (c);
1467  return form;
1468}
1469