summaryrefslogtreecommitdiff
path: root/gcc/fortran/target-memory.c
blob: ddb6b4f38971281fe4a98f679a7dcf7ad6072bf1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
/* Simulate storage of variables into target memory.
   Copyright (C) 2007-2015 Free Software Foundation, Inc.
   Contributed by Paul Thomas and Brooks Moses

This file is part of GCC.

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

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

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "flags.h"
#include "alias.h"
#include "symtab.h"
#include "tree.h"
#include "fold-const.h"
#include "stor-layout.h"
#include "gfortran.h"
#include "arith.h"
#include "constructor.h"
#include "trans.h"
#include "trans-const.h"
#include "trans-types.h"
#include "target-memory.h"

/* --------------------------------------------------------------- */
/* Calculate the size of an expression.  */


static size_t
size_integer (int kind)
{
  return GET_MODE_SIZE (TYPE_MODE (gfc_get_int_type (kind)));;
}


static size_t
size_float (int kind)
{
  return GET_MODE_SIZE (TYPE_MODE (gfc_get_real_type (kind)));;
}


static size_t
size_complex (int kind)
{
  return 2 * size_float (kind);
}


static size_t
size_logical (int kind)
{
  return GET_MODE_SIZE (TYPE_MODE (gfc_get_logical_type (kind)));;
}


static size_t
size_character (int length, int kind)
{
  int i = gfc_validate_kind (BT_CHARACTER, kind, false);
  return length * gfc_character_kinds[i].bit_size / 8;
}


/* Return the size of a single element of the given expression.
   Identical to gfc_target_expr_size for scalars.  */

size_t
gfc_element_size (gfc_expr *e)
{
  tree type;

  switch (e->ts.type)
    {
    case BT_INTEGER:
      return size_integer (e->ts.kind);
    case BT_REAL:
      return size_float (e->ts.kind);
    case BT_COMPLEX:
      return size_complex (e->ts.kind);
    case BT_LOGICAL:
      return size_logical (e->ts.kind);
    case BT_CHARACTER:
      if (e->expr_type == EXPR_CONSTANT)
	return size_character (e->value.character.length, e->ts.kind);
      else if (e->ts.u.cl != NULL && e->ts.u.cl->length != NULL
	       && e->ts.u.cl->length->expr_type == EXPR_CONSTANT
	       && e->ts.u.cl->length->ts.type == BT_INTEGER)
	{
	  int length;

	  gfc_extract_int (e->ts.u.cl->length, &length);
	  return size_character (length, e->ts.kind);
	}
      else
	return 0;

    case BT_HOLLERITH:
      return e->representation.length;
    case BT_DERIVED:
    case BT_CLASS:
    case BT_VOID:
    case BT_ASSUMED:
      {
	/* Determine type size without clobbering the typespec for ISO C
	   binding types.  */
	gfc_typespec ts;
	HOST_WIDE_INT size;
	ts = e->ts;
	type = gfc_typenode_for_spec (&ts);
	size = int_size_in_bytes (type);
	gcc_assert (size >= 0);
	return size;
      }
    default:
      gfc_internal_error ("Invalid expression in gfc_element_size.");
      return 0;
    }
}


/* Return the size of an expression in its target representation.  */

size_t
gfc_target_expr_size (gfc_expr *e)
{
  mpz_t tmp;
  size_t asz;

  gcc_assert (e != NULL);

  if (e->rank)
    {
      if (gfc_array_size (e, &tmp))
	asz = mpz_get_ui (tmp);
      else
	asz = 0;
    }
  else
    asz = 1;

  return asz * gfc_element_size (e);
}


/* The encode_* functions export a value into a buffer, and
   return the number of bytes of the buffer that have been
   used.  */

static unsigned HOST_WIDE_INT
encode_array (gfc_expr *expr, unsigned char *buffer, size_t buffer_size)
{
  mpz_t array_size;
  int i;
  int ptr = 0;

  gfc_constructor_base ctor = expr->value.constructor;

  gfc_array_size (expr, &array_size);
  for (i = 0; i < (int)mpz_get_ui (array_size); i++)
    {
      ptr += gfc_target_encode_expr (gfc_constructor_lookup_expr (ctor, i),
				     &buffer[ptr], buffer_size - ptr);
    }

  mpz_clear (array_size);
  return ptr;
}


static int
encode_integer (int kind, mpz_t integer, unsigned char *buffer,
		size_t buffer_size)
{
  return native_encode_expr (gfc_conv_mpz_to_tree (integer, kind),
			     buffer, buffer_size);
}


static int
encode_float (int kind, mpfr_t real, unsigned char *buffer, size_t buffer_size)
{
  return native_encode_expr (gfc_conv_mpfr_to_tree (real, kind, 0), buffer,
			     buffer_size);
}


static int
encode_complex (int kind, mpc_t cmplx,
		unsigned char *buffer, size_t buffer_size)
{
  int size;
  size = encode_float (kind, mpc_realref (cmplx), &buffer[0], buffer_size);
  size += encode_float (kind, mpc_imagref (cmplx),
			&buffer[size], buffer_size - size);
  return size;
}


static int
encode_logical (int kind, int logical, unsigned char *buffer, size_t buffer_size)
{
  return native_encode_expr (build_int_cst (gfc_get_logical_type (kind),
					    logical),
			     buffer, buffer_size);
}


int
gfc_encode_character (int kind, int length, const gfc_char_t *string,
		      unsigned char *buffer, size_t buffer_size)
{
  size_t elsize = size_character (1, kind);
  tree type = gfc_get_char_type (kind);
  int i;

  gcc_assert (buffer_size >= size_character (length, kind));

  for (i = 0; i < length; i++)
    native_encode_expr (build_int_cst (type, string[i]), &buffer[i*elsize],
			elsize);

  return length;
}


static unsigned HOST_WIDE_INT
encode_derived (gfc_expr *source, unsigned char *buffer, size_t buffer_size)
{
  gfc_constructor *c;
  gfc_component *cmp;
  int ptr;
  tree type;
  HOST_WIDE_INT size;

  type = gfc_typenode_for_spec (&source->ts);

  for (c = gfc_constructor_first (source->value.constructor),
       cmp = source->ts.u.derived->components;
       c;
       c = gfc_constructor_next (c), cmp = cmp->next)
    {
      gcc_assert (cmp);
      if (!c->expr)
	continue;
      ptr = TREE_INT_CST_LOW(DECL_FIELD_OFFSET(cmp->backend_decl))
	    + TREE_INT_CST_LOW(DECL_FIELD_BIT_OFFSET(cmp->backend_decl))/8;

      if (c->expr->expr_type == EXPR_NULL)
	{
	  size = int_size_in_bytes (TREE_TYPE (cmp->backend_decl));
	  gcc_assert (size >= 0);
	  memset (&buffer[ptr], 0, size);
	}
      else
	gfc_target_encode_expr (c->expr, &buffer[ptr],
				buffer_size - ptr);
    }

  size = int_size_in_bytes (type);
  gcc_assert (size >= 0);
  return size;
}


/* Write a constant expression in binary form to a buffer.  */
unsigned HOST_WIDE_INT
gfc_target_encode_expr (gfc_expr *source, unsigned char *buffer,
			size_t buffer_size)
{
  if (source == NULL)
    return 0;

  if (source->expr_type == EXPR_ARRAY)
    return encode_array (source, buffer, buffer_size);

  gcc_assert (source->expr_type == EXPR_CONSTANT
	      || source->expr_type == EXPR_STRUCTURE
	      || source->expr_type == EXPR_SUBSTRING);

  /* If we already have a target-memory representation, we use that rather
     than recreating one.  */
  if (source->representation.string)
    {
      memcpy (buffer, source->representation.string,
	      source->representation.length);
      return source->representation.length;
    }

  switch (source->ts.type)
    {
    case BT_INTEGER:
      return encode_integer (source->ts.kind, source->value.integer, buffer,
			     buffer_size);
    case BT_REAL:
      return encode_float (source->ts.kind, source->value.real, buffer,
			   buffer_size);
    case BT_COMPLEX:
      return encode_complex (source->ts.kind, source->value.complex,
			     buffer, buffer_size);
    case BT_LOGICAL:
      return encode_logical (source->ts.kind, source->value.logical, buffer,
			     buffer_size);
    case BT_CHARACTER:
      if (source->expr_type == EXPR_CONSTANT || source->ref == NULL)
	return gfc_encode_character (source->ts.kind,
				     source->value.character.length,
				     source->value.character.string,
				     buffer, buffer_size);
      else
	{
	  int start, end;

	  gcc_assert (source->expr_type == EXPR_SUBSTRING);
	  gfc_extract_int (source->ref->u.ss.start, &start);
	  gfc_extract_int (source->ref->u.ss.end, &end);
	  return gfc_encode_character (source->ts.kind, MAX(end - start + 1, 0),
				       &source->value.character.string[start-1],
				       buffer, buffer_size);
	}

    case BT_DERIVED:
      if (source->ts.u.derived->ts.f90_type == BT_VOID)
	{
	  gfc_constructor *c;
	  gcc_assert (source->expr_type == EXPR_STRUCTURE);
	  c = gfc_constructor_first (source->value.constructor);
	  gcc_assert (c->expr->expr_type == EXPR_CONSTANT
		      && c->expr->ts.type == BT_INTEGER);
	  return encode_integer (gfc_index_integer_kind, c->expr->value.integer,
				 buffer, buffer_size);
	}

      return encode_derived (source, buffer, buffer_size);
    default:
      gfc_internal_error ("Invalid expression in gfc_target_encode_expr.");
      return 0;
    }
}


static int
interpret_array (unsigned char *buffer, size_t buffer_size, gfc_expr *result)
{
  gfc_constructor_base base = NULL;
  int array_size = 1;
  int i;
  int ptr = 0;

  /* Calculate array size from its shape and rank.  */
  gcc_assert (result->rank > 0 && result->shape);

  for (i = 0; i < result->rank; i++)
    array_size *= (int)mpz_get_ui (result->shape[i]);

  /* Iterate over array elements, producing constructors.  */
  for (i = 0; i < array_size; i++)
    {
      gfc_expr *e = gfc_get_constant_expr (result->ts.type, result->ts.kind,
					   &result->where);
      e->ts = result->ts;

      if (e->ts.type == BT_CHARACTER)
	e->value.character.length = result->value.character.length;

      gfc_constructor_append_expr (&base, e, &result->where);

      ptr += gfc_target_interpret_expr (&buffer[ptr], buffer_size - ptr, e,
					true);
    }

  result->value.constructor = base;
  return ptr;
}


int
gfc_interpret_integer (int kind, unsigned char *buffer, size_t buffer_size,
		   mpz_t integer)
{
  mpz_init (integer);
  gfc_conv_tree_to_mpz (integer,
			native_interpret_expr (gfc_get_int_type (kind),
					       buffer, buffer_size));
  return size_integer (kind);
}


int
gfc_interpret_float (int kind, unsigned char *buffer, size_t buffer_size,
		     mpfr_t real)
{
  gfc_set_model_kind (kind);
  mpfr_init (real);
  gfc_conv_tree_to_mpfr (real,
			 native_interpret_expr (gfc_get_real_type (kind),
						buffer, buffer_size));

  return size_float (kind);
}


int
gfc_interpret_complex (int kind, unsigned char *buffer, size_t buffer_size,
		       mpc_t complex)
{
  int size;
  size = gfc_interpret_float (kind, &buffer[0], buffer_size,
			      mpc_realref (complex));
  size += gfc_interpret_float (kind, &buffer[size], buffer_size - size,
			       mpc_imagref (complex));
  return size;
}


int
gfc_interpret_logical (int kind, unsigned char *buffer, size_t buffer_size,
		   int *logical)
{
  tree t = native_interpret_expr (gfc_get_logical_type (kind), buffer,
				  buffer_size);
  *logical = wi::eq_p (t, 0) ? 0 : 1;
  return size_logical (kind);
}


int
gfc_interpret_character (unsigned char *buffer, size_t buffer_size,
			 gfc_expr *result)
{
  int i;

  if (result->ts.u.cl && result->ts.u.cl->length)
    result->value.character.length =
      (int) mpz_get_ui (result->ts.u.cl->length->value.integer);

  gcc_assert (buffer_size >= size_character (result->value.character.length,
					     result->ts.kind));
  result->value.character.string =
    gfc_get_wide_string (result->value.character.length + 1);

  if (result->ts.kind == gfc_default_character_kind)
    for (i = 0; i < result->value.character.length; i++)
      result->value.character.string[i] = (gfc_char_t) buffer[i];
  else
    {
      mpz_t integer;
      unsigned bytes = size_character (1, result->ts.kind);
      mpz_init (integer);
      gcc_assert (bytes <= sizeof (unsigned long));

      for (i = 0; i < result->value.character.length; i++)
	{
	  gfc_conv_tree_to_mpz (integer,
	    native_interpret_expr (gfc_get_char_type (result->ts.kind),
				   &buffer[bytes*i], buffer_size-bytes*i));
	  result->value.character.string[i]
	    = (gfc_char_t) mpz_get_ui (integer);
	}

      mpz_clear (integer);
    }

  result->value.character.string[result->value.character.length] = '\0';

  return result->value.character.length;
}


int
gfc_interpret_derived (unsigned char *buffer, size_t buffer_size, gfc_expr *result)
{
  gfc_component *cmp;
  int ptr;
  tree type;

  /* The attributes of the derived type need to be bolted to the floor.  */
  result->expr_type = EXPR_STRUCTURE;

  cmp = result->ts.u.derived->components;

  if (result->ts.u.derived->from_intmod == INTMOD_ISO_C_BINDING
      && (result->ts.u.derived->intmod_sym_id == ISOCBINDING_PTR
	  || result->ts.u.derived->intmod_sym_id == ISOCBINDING_FUNPTR))
    {
      gfc_constructor *c;
      gfc_expr *e;
      /* Needed as gfc_typenode_for_spec as gfc_typenode_for_spec
	 sets this to BT_INTEGER.  */
      result->ts.type = BT_DERIVED;
      e = gfc_get_constant_expr (cmp->ts.type, cmp->ts.kind, &result->where);
      c = gfc_constructor_append_expr (&result->value.constructor, e, NULL);
      c->n.component = cmp;
      gfc_target_interpret_expr (buffer, buffer_size, e, true);
      e->ts.is_iso_c = 1;
      return int_size_in_bytes (ptr_type_node);
    }

  type = gfc_typenode_for_spec (&result->ts);

  /* Run through the derived type components.  */
  for (;cmp; cmp = cmp->next)
    {
      gfc_constructor *c;
      gfc_expr *e = gfc_get_constant_expr (cmp->ts.type, cmp->ts.kind,
					   &result->where);
      e->ts = cmp->ts;

      /* Copy shape, if needed.  */
      if (cmp->as && cmp->as->rank)
	{
	  int n;

	  e->expr_type = EXPR_ARRAY;
	  e->rank = cmp->as->rank;

	  e->shape = gfc_get_shape (e->rank);
	  for (n = 0; n < e->rank; n++)
	     {
	       mpz_init_set_ui (e->shape[n], 1);
	       mpz_add (e->shape[n], e->shape[n],
			cmp->as->upper[n]->value.integer);
	       mpz_sub (e->shape[n], e->shape[n],
			cmp->as->lower[n]->value.integer);
	     }
	}

      c = gfc_constructor_append_expr (&result->value.constructor, e, NULL);

      /* The constructor points to the component.  */
      c->n.component = cmp;

      /* Calculate the offset, which consists of the FIELD_OFFSET in
	 bytes, which appears in multiples of DECL_OFFSET_ALIGN-bit-sized,
	 and additional bits of FIELD_BIT_OFFSET. The code assumes that all
	 sizes of the components are multiples of BITS_PER_UNIT,
	 i.e. there are, e.g., no bit fields.  */

      gcc_assert (cmp->backend_decl);
      ptr = TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (cmp->backend_decl));
      gcc_assert (ptr % 8 == 0);
      ptr = ptr/8 + TREE_INT_CST_LOW (DECL_FIELD_OFFSET (cmp->backend_decl));

      gfc_target_interpret_expr (&buffer[ptr], buffer_size - ptr, e, true);
    }

  return int_size_in_bytes (type);
}


/* Read a binary buffer to a constant expression.  */
int
gfc_target_interpret_expr (unsigned char *buffer, size_t buffer_size,
			   gfc_expr *result, bool convert_widechar)
{
  if (result->expr_type == EXPR_ARRAY)
    return interpret_array (buffer, buffer_size, result);

  switch (result->ts.type)
    {
    case BT_INTEGER:
      result->representation.length =
        gfc_interpret_integer (result->ts.kind, buffer, buffer_size,
			       result->value.integer);
      break;

    case BT_REAL:
      result->representation.length =
        gfc_interpret_float (result->ts.kind, buffer, buffer_size,
    			     result->value.real);
      break;

    case BT_COMPLEX:
      result->representation.length =
        gfc_interpret_complex (result->ts.kind, buffer, buffer_size,
			       result->value.complex);
      break;

    case BT_LOGICAL:
      result->representation.length =
        gfc_interpret_logical (result->ts.kind, buffer, buffer_size,
			       &result->value.logical);
      break;

    case BT_CHARACTER:
      result->representation.length =
        gfc_interpret_character (buffer, buffer_size, result);
      break;

    case BT_CLASS:
      result->ts = CLASS_DATA (result)->ts;
      /* Fall through.  */
    case BT_DERIVED:
      result->representation.length =
        gfc_interpret_derived (buffer, buffer_size, result);
      gcc_assert (result->representation.length >= 0);
      break;

    default:
      gfc_internal_error ("Invalid expression in gfc_target_interpret_expr.");
      break;
    }

  if (result->ts.type == BT_CHARACTER && convert_widechar)
    result->representation.string
      = gfc_widechar_to_char (result->value.character.string,
			      result->value.character.length);
  else
    {
      result->representation.string =
        XCNEWVEC (char, result->representation.length + 1);
      memcpy (result->representation.string, buffer,
	      result->representation.length);
      result->representation.string[result->representation.length] = '\0';
    }

  return result->representation.length;
}


/* --------------------------------------------------------------- */
/* Two functions used by trans-common.c to write overlapping
   equivalence initializers to a buffer.  This is added to the union
   and the original initializers freed.  */


/* Writes the values of a constant expression to a char buffer. If another
   unequal initializer has already been written to the buffer, this is an
   error.  */

static size_t
expr_to_char (gfc_expr *e, unsigned char *data, unsigned char *chk, size_t len)
{
  int i;
  int ptr;
  gfc_constructor *c;
  gfc_component *cmp;
  unsigned char *buffer;

  if (e == NULL)
    return 0;

  /* Take a derived type, one component at a time, using the offsets from the backend
     declaration.  */
  if (e->ts.type == BT_DERIVED)
    {
      for (c = gfc_constructor_first (e->value.constructor),
	   cmp = e->ts.u.derived->components;
	   c; c = gfc_constructor_next (c), cmp = cmp->next)
	{
	  gcc_assert (cmp && cmp->backend_decl);
	  if (!c->expr)
	    continue;
	  ptr = TREE_INT_CST_LOW(DECL_FIELD_OFFSET(cmp->backend_decl))
	    + TREE_INT_CST_LOW(DECL_FIELD_BIT_OFFSET(cmp->backend_decl))/8;
	  expr_to_char (c->expr, &data[ptr], &chk[ptr], len);
	}
      return len;
    }

  /* Otherwise, use the target-memory machinery to write a bitwise image, appropriate
     to the target, in a buffer and check off the initialized part of the buffer.  */
  len = gfc_target_expr_size (e);
  buffer = (unsigned char*)alloca (len);
  len = gfc_target_encode_expr (e, buffer, len);

    for (i = 0; i < (int)len; i++)
    {
      if (chk[i] && (buffer[i] != data[i]))
	{
	  gfc_error ("Overlapping unequal initializers in EQUIVALENCE "
		     "at %L", &e->where);
	  return 0;
	}
      chk[i] = 0xFF;
    }

  memcpy (data, buffer, len);
  return len;
}


/* Writes the values from the equivalence initializers to a char* array
   that will be written to the constructor to make the initializer for
   the union declaration.  */

size_t
gfc_merge_initializers (gfc_typespec ts, gfc_expr *e, unsigned char *data,
			unsigned char *chk, size_t length)
{
  size_t len = 0;
  gfc_constructor * c;

  switch (e->expr_type)
    {
    case EXPR_CONSTANT:
    case EXPR_STRUCTURE:
      len = expr_to_char (e, &data[0], &chk[0], length);

      break;

    case EXPR_ARRAY:
      for (c = gfc_constructor_first (e->value.constructor);
	   c; c = gfc_constructor_next (c))
	{
	  size_t elt_size = gfc_target_expr_size (c->expr);

	  if (mpz_cmp_si (c->offset, 0) != 0)
	    len = elt_size * (size_t)mpz_get_si (c->offset);

	  len = len + gfc_merge_initializers (ts, c->expr, &data[len],
					      &chk[len], length - len);
	}
      break;

    default:
      return 0;
    }

  return len;
}


/* Transfer the bitpattern of a (integer) BOZ to real or complex variables.
   When successful, no BOZ or nothing to do, true is returned.  */

bool
gfc_convert_boz (gfc_expr *expr, gfc_typespec *ts)
{
  size_t buffer_size, boz_bit_size, ts_bit_size;
  int index;
  unsigned char *buffer;

  if (!expr->is_boz)
    return true;

  gcc_assert (expr->expr_type == EXPR_CONSTANT
	      && expr->ts.type == BT_INTEGER);

  /* Don't convert BOZ to logical, character, derived etc.  */
  if (ts->type == BT_REAL)
    {
      buffer_size = size_float (ts->kind);
      ts_bit_size = buffer_size * 8;
    }
  else if (ts->type == BT_COMPLEX)
    {
      buffer_size = size_complex (ts->kind);
      ts_bit_size = buffer_size * 8 / 2;
    }
  else
    return true;

  /* Convert BOZ to the smallest possible integer kind.  */
  boz_bit_size = mpz_sizeinbase (expr->value.integer, 2);

  if (boz_bit_size > ts_bit_size)
    {
      gfc_error_now ("BOZ constant at %L is too large (%ld vs %ld bits)",
		     &expr->where, (long) boz_bit_size, (long) ts_bit_size);
      return false;
    }

  for (index = 0; gfc_integer_kinds[index].kind != 0; ++index)
    if ((unsigned) gfc_integer_kinds[index].bit_size >= ts_bit_size)
      break;

  expr->ts.kind = gfc_integer_kinds[index].kind;
  buffer_size = MAX (buffer_size, size_integer (expr->ts.kind));

  buffer = (unsigned char*)alloca (buffer_size);
  encode_integer (expr->ts.kind, expr->value.integer, buffer, buffer_size);
  mpz_clear (expr->value.integer);

  if (ts->type == BT_REAL)
    {
      mpfr_init (expr->value.real);
      gfc_interpret_float (ts->kind, buffer, buffer_size, expr->value.real);
    }
  else
    {
      mpc_init2 (expr->value.complex, mpfr_get_default_prec());
      gfc_interpret_complex (ts->kind, buffer, buffer_size,
			     expr->value.complex);
    }
  expr->is_boz = 0;
  expr->ts.type = ts->type;
  expr->ts.kind = ts->kind;

  return true;
}