aboutsummaryrefslogtreecommitdiff
path: root/bfd/wasm-module.c
blob: c32a0b617417915bd26bcfb98ae99bfdb62a2bd2 (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
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
/* BFD back-end for WebAssembly modules.
   Copyright (C) 2017-2018 Free Software Foundation, Inc.

   Based on srec.c, mmo.c, and binary.c

   This file is part of BFD, the Binary File Descriptor library.

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

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

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */

/* The WebAssembly module format is a simple object file format
   including up to 11 numbered sections, plus any number of named
   "custom" sections. It is described at:
   https://github.com/WebAssembly/design/blob/master/BinaryEncoding.md. */

#include "sysdep.h"
#include "alloca-conf.h"
#include "bfd.h"
#include "sysdep.h"
#include <limits.h>
#include "bfd_stdint.h"
#include "libiberty.h"
#include "libbfd.h"
#include "wasm-module.h"

typedef struct
{
  asymbol *      symbols;
  bfd_size_type  symcount;
} tdata_type;

static const char * const wasm_numbered_sections[] =
{
  NULL, /* Custom section, different layout.  */
  WASM_SECTION ( 1, "type"),
  WASM_SECTION ( 2, "import"),
  WASM_SECTION ( 3, "function"),
  WASM_SECTION ( 4, "table"),
  WASM_SECTION ( 5, "memory"),
  WASM_SECTION ( 6, "global"),
  WASM_SECTION ( 7, "export"),
  WASM_SECTION ( 8, "start"),
  WASM_SECTION ( 9, "element"),
  WASM_SECTION (10, "code"),
  WASM_SECTION (11, "data"),
};

#define WASM_NUMBERED_SECTIONS ARRAY_SIZE (wasm_numbered_sections)

/* Resolve SECTION_CODE to a section name if there is one, NULL
   otherwise.  */

static const char *
wasm_section_code_to_name (bfd_byte section_code)
{
  if (section_code < WASM_NUMBERED_SECTIONS)
    return wasm_numbered_sections[section_code];

  return NULL;
}

/* Translate section name NAME to a section code, or 0 if it's a
   custom name.  */

static unsigned int
wasm_section_name_to_code (const char *name)
{
  unsigned i;

  for (i = 1; i < WASM_NUMBERED_SECTIONS; i++)
    if (strcmp (name, wasm_numbered_sections[i]) == 0)
      return i;

  return 0;
}

/* WebAssembly LEB128 integers are sufficiently like DWARF LEB128
   integers that we use _bfd_safe_read_leb128, but there are two
   points of difference:

   - WebAssembly requires a 32-bit value to be encoded in at most 5
     bytes, etc.
   - _bfd_safe_read_leb128 accepts incomplete LEB128 encodings at the
     end of the buffer, while these are invalid in WebAssembly.

   Those differences mean that we will accept some files that are
   invalid WebAssembly.  */

/* Read an LEB128-encoded integer from ABFD's I/O stream, reading one
   byte at a time.  Set ERROR_RETURN if no complete integer could be
   read, LENGTH_RETURN to the number of bytes read (including bytes in
   incomplete numbers).  SIGN means interpret the number as SLEB128. */

static bfd_vma
wasm_read_leb128 (bfd *		  abfd,
		  bfd_boolean *	  error_return,
		  unsigned int *  length_return,
		  bfd_boolean	  sign)
{
  bfd_vma result = 0;
  unsigned int num_read = 0;
  unsigned int shift = 0;
  unsigned char byte = 0;
  bfd_boolean success = FALSE;

  while (bfd_bread (&byte, 1, abfd) == 1)
    {
      num_read++;

      result |= ((bfd_vma) (byte & 0x7f)) << shift;

      shift += 7;
      if ((byte & 0x80) == 0)
	{
	  success = TRUE;
	  break;
	}
    }

  if (length_return != NULL)
    *length_return = num_read;
  if (error_return != NULL)
    *error_return = ! success;

  if (sign && (shift < 8 * sizeof (result)) && (byte & 0x40))
    result |= -((bfd_vma) 1 << shift);

  return result;
}

/* Encode an integer V as LEB128 and write it to ABFD, return TRUE on
   success.  */

static bfd_boolean
wasm_write_uleb128 (bfd *abfd, bfd_vma v)
{
  do
    {
      bfd_byte c = v & 0x7f;
      v >>= 7;

      if (v)
	c |= 0x80;

      if (bfd_bwrite (&c, 1, abfd) != 1)
	return FALSE;
    }
  while (v);

  return TRUE;
}

/* Read the LEB128 integer at P, saving it to X; at end of buffer,
   jump to error_return.  */
#define READ_LEB128(x, p, end)						\
  do									\
    {									\
      unsigned int length_read;						\
      (x) = _bfd_safe_read_leb128 (abfd, (p), &length_read,		\
				   FALSE, (end));			\
      (p) += length_read;						\
      if (length_read == 0)						\
	goto error_return;						\
    }									\
  while (0)

/* Verify the magic number at the beginning of a WebAssembly module
   ABFD, setting ERRORPTR if there's a mismatch.  */

static bfd_boolean
wasm_read_magic (bfd *abfd, bfd_boolean *errorptr)
{
  bfd_byte magic_const[SIZEOF_WASM_MAGIC] = WASM_MAGIC;
  bfd_byte magic[SIZEOF_WASM_MAGIC];

  if (bfd_bread (magic, sizeof (magic), abfd) == sizeof (magic)
      && memcmp (magic, magic_const, sizeof (magic)) == 0)
    return TRUE;

  *errorptr = TRUE;
  return FALSE;
}

/* Read the version number from ABFD, returning TRUE if it's a supported
   version. Set ERRORPTR otherwise.  */

static bfd_boolean
wasm_read_version (bfd *abfd, bfd_boolean *errorptr)
{
  bfd_byte vers_const[SIZEOF_WASM_VERSION] = WASM_VERSION;
  bfd_byte vers[SIZEOF_WASM_VERSION];

  if (bfd_bread (vers, sizeof (vers), abfd) == sizeof (vers)
      /* Don't attempt to parse newer versions, which are likely to
	 require code changes.  */
      && memcmp (vers, vers_const, sizeof (vers)) == 0)
    return TRUE;

  *errorptr = TRUE;
  return FALSE;
}

/* Read the WebAssembly header (magic number plus version number) from
   ABFD, setting ERRORPTR to TRUE if there is a mismatch.  */

static bfd_boolean
wasm_read_header (bfd *abfd, bfd_boolean *errorptr)
{
  if (! wasm_read_magic (abfd, errorptr))
    return FALSE;

  if (! wasm_read_version (abfd, errorptr))
    return FALSE;

  return TRUE;
}

/* Scan the "function" subsection of the "name" section ASECT in the
   wasm module ABFD. Create symbols. Return TRUE on success.  */

static bfd_boolean
wasm_scan_name_function_section (bfd *abfd, sec_ptr asect)
{
  bfd_byte *p;
  bfd_byte *end;
  bfd_vma payload_size;
  bfd_vma symcount = 0;
  tdata_type *tdata = abfd->tdata.any;
  asymbol *symbols = NULL;
  sec_ptr space_function_index;

  if (! asect)
    return FALSE;

  if (strcmp (asect->name, WASM_NAME_SECTION) != 0)
    return FALSE;

  p = asect->contents;
  end = asect->contents + asect->size;

  if (! p)
    return FALSE;

  while (p < end)
    {
      bfd_byte subsection_code = *p++;
      if (subsection_code == WASM_FUNCTION_SUBSECTION)
	break;

      /* subsection_code is documented to be a varuint7, meaning that
	 it has to be a single byte in the 0 - 127 range.  If it isn't,
	 the spec must have changed underneath us, so give up.  */
      if (subsection_code & 0x80)
	return FALSE;

      READ_LEB128 (payload_size, p, end);

      if (p > p + payload_size)
	return FALSE;

      p += payload_size;
    }

  if (p >= end)
    return FALSE;

  READ_LEB128 (payload_size, p, end);

  if (p > p + payload_size)
    return FALSE;

  if (p + payload_size > end)
    return FALSE;

  end = p + payload_size;

  READ_LEB128 (symcount, p, end);

  /* Sanity check: each symbol has at least two bytes.  */
  if (symcount > payload_size/2)
    return FALSE;

  tdata->symcount = symcount;

  space_function_index = bfd_make_section_with_flags
    (abfd, WASM_SECTION_FUNCTION_INDEX, SEC_READONLY | SEC_CODE);

  if (! space_function_index)
    space_function_index = bfd_get_section_by_name (abfd, WASM_SECTION_FUNCTION_INDEX);

  if (! space_function_index)
    return FALSE;

  symbols = bfd_zalloc (abfd, tdata->symcount * sizeof (asymbol));
  if (! symbols)
    return FALSE;

  for (symcount = 0; p < end && symcount < tdata->symcount; symcount++)
    {
      bfd_vma idx;
      bfd_vma len;
      char *name;
      asymbol *sym;

      READ_LEB128 (idx, p, end);
      READ_LEB128 (len, p, end);

      if (p + len < p || p + len > end)
	goto error_return;

      name = bfd_zalloc (abfd, len + 1);
      if (! name)
	goto error_return;

      memcpy (name, p, len);
      p += len;

      sym = &symbols[symcount];
      sym->the_bfd = abfd;
      sym->name = name;
      sym->value = idx;
      sym->flags = BSF_GLOBAL | BSF_FUNCTION;
      sym->section = space_function_index;
      sym->udata.p = NULL;
    }

  if (symcount < tdata->symcount)
    goto error_return;

  tdata->symbols = symbols;
  abfd->symcount = symcount;

  return TRUE;

 error_return:
  while (symcount)
    bfd_release (abfd, (void *)symbols[--symcount].name);
  bfd_release (abfd, symbols);
  return FALSE;
}

/* Read a byte from ABFD and return it, or EOF for EOF or error.
   Set ERRORPTR on non-EOF error.  */

static int
wasm_read_byte (bfd *abfd, bfd_boolean *errorptr)
{
  bfd_byte byte;

  if (bfd_bread (&byte, (bfd_size_type) 1, abfd) != 1)
    {
      if (bfd_get_error () != bfd_error_file_truncated)
	*errorptr = TRUE;
      return EOF;
    }

  return byte;
}

/* Scan the wasm module ABFD, creating sections and symbols.
   Return TRUE on success.  */

static bfd_boolean
wasm_scan (bfd *abfd)
{
  bfd_boolean error = FALSE;
  /* Fake VMAs for now. Choose 0x80000000 as base to avoid clashes
     with actual data addresses.  */
  bfd_vma vma = 0x80000000;
  int section_code;
  unsigned int bytes_read;
  char *name = NULL;
  asection *bfdsec;

  if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
    goto error_return;

  if (! wasm_read_header (abfd, &error))
    goto error_return;

  while ((section_code = wasm_read_byte (abfd, &error)) != EOF)
    {
      if (section_code != 0)
	{
	  const char *sname = wasm_section_code_to_name (section_code);

	  if (! sname)
	    goto error_return;

	  name = strdup (sname);
	  bfdsec = bfd_make_section_anyway_with_flags (abfd, name, SEC_HAS_CONTENTS);
	  if (bfdsec == NULL)
	    goto error_return;
	  name = NULL;

	  bfdsec->vma = vma;
	  bfdsec->lma = vma;
	  bfdsec->size = wasm_read_leb128 (abfd, &error, &bytes_read, FALSE);
	  if (error)
	    goto error_return;
	  bfdsec->filepos = bfd_tell (abfd);
	  bfdsec->alignment_power = 0;
	}
      else
	{
	  bfd_vma payload_len;
	  file_ptr section_start;
	  bfd_vma namelen;
	  char *prefix = WASM_SECTION_PREFIX;
	  char *p;
	  int ret;

	  payload_len = wasm_read_leb128 (abfd, &error, &bytes_read, FALSE);
	  if (error)
	    goto error_return;
	  section_start = bfd_tell (abfd);
	  namelen = wasm_read_leb128 (abfd, &error, &bytes_read, FALSE);
	  if (error || namelen > payload_len)
	    goto error_return;
	  name = bfd_zmalloc (namelen + strlen (prefix) + 1);
	  if (! name)
	    goto error_return;
	  p = name;
	  ret = sprintf (p, "%s", prefix);
	  if (ret < 0 || (bfd_vma) ret != strlen (prefix))
	    goto error_return;
	  p += ret;
	  if (bfd_bread (p, namelen, abfd) != namelen)
	    goto error_return;

	  bfdsec = bfd_make_section_anyway_with_flags (abfd, name, SEC_HAS_CONTENTS);
	  if (bfdsec == NULL)
	    goto error_return;
	  name = NULL;

	  bfdsec->vma = vma;
	  bfdsec->lma = vma;
	  bfdsec->filepos = bfd_tell (abfd);
	  bfdsec->size = section_start + payload_len - bfdsec->filepos;
	  bfdsec->alignment_power = 0;
	}

      if (bfdsec->size != 0)
	{
	  bfdsec->contents = bfd_zalloc (abfd, bfdsec->size);
	  if (! bfdsec->contents)
	    goto error_return;

	  if (bfd_bread (bfdsec->contents, bfdsec->size, abfd) != bfdsec->size)
	    goto error_return;
	}

      vma += bfdsec->size;
    }

  /* Make sure we're at actual EOF.  There's no indication in the
     WebAssembly format of how long the file is supposed to be.  */
  if (error)
    goto error_return;

  return TRUE;

 error_return:
  if (name)
    free (name);

  for (bfdsec = abfd->sections; bfdsec; bfdsec = bfdsec->next)
    free ((void *) bfdsec->name);

  return FALSE;
}

/* Put a numbered section ASECT of ABFD into the table of numbered
   sections pointed to by FSARG.  */

static void
wasm_register_section (bfd *abfd ATTRIBUTE_UNUSED,
		       asection *asect,
		       void *fsarg)
{
  sec_ptr *numbered_sections = fsarg;
  int idx = wasm_section_name_to_code (asect->name);

  if (idx == 0)
    return;

  numbered_sections[idx] = asect;
}

struct compute_section_arg
{
  bfd_vma pos;
  bfd_boolean failed;
};

/* Compute the file position of ABFD's section ASECT.  FSARG is a
   pointer to the current file position.

   We allow section names of the form .wasm.id to encode the numbered
   section with ID id, if it exists; otherwise, a custom section with
   ID "id" is produced.  Arbitrary section names are for sections that
   are assumed already to contain a section header; those are appended
   to the WebAssembly module verbatim.  */

static void
wasm_compute_custom_section_file_position (bfd *abfd,
					   sec_ptr asect,
					   void *fsarg)
{
  struct compute_section_arg *fs = fsarg;
  int idx;

  if (fs->failed)
    return;

  idx = wasm_section_name_to_code (asect->name);

  if (idx != 0)
    return;

  if (CONST_STRNEQ (asect->name, WASM_SECTION_PREFIX))
    {
      const char *name = asect->name + strlen (WASM_SECTION_PREFIX);
      bfd_size_type payload_len = asect->size;
      bfd_size_type name_len = strlen (name);
      bfd_size_type nl = name_len;

      payload_len += name_len;

      do
	{
	  payload_len++;
	  nl >>= 7;
	}
      while (nl);

      bfd_seek (abfd, fs->pos, SEEK_SET);
      if (! wasm_write_uleb128 (abfd, 0)
	  || ! wasm_write_uleb128 (abfd, payload_len)
	  || ! wasm_write_uleb128 (abfd, name_len)
	  || bfd_bwrite (name, name_len, abfd) != name_len)
	goto error_return;
      fs->pos = asect->filepos = bfd_tell (abfd);
    }
  else
    {
      asect->filepos = fs->pos;
    }


  fs->pos += asect->size;
  return;

 error_return:
  fs->failed = TRUE;
}

/* Compute the file positions for the sections of ABFD.  Currently,
   this writes all numbered sections first, in order, then all custom
   sections, in section order.

   The spec says that the numbered sections must appear in order of
   their ids, but custom sections can appear in any position and any
   order, and more than once. FIXME: support that.  */

static bfd_boolean
wasm_compute_section_file_positions (bfd *abfd)
{
  bfd_byte magic[SIZEOF_WASM_MAGIC] = WASM_MAGIC;
  bfd_byte vers[SIZEOF_WASM_VERSION] = WASM_VERSION;
  sec_ptr numbered_sections[WASM_NUMBERED_SECTIONS];
  struct compute_section_arg fs;
  unsigned int i;

  bfd_seek (abfd, (bfd_vma) 0, SEEK_SET);

  if (bfd_bwrite (magic, sizeof (magic), abfd) != (sizeof magic)
      || bfd_bwrite (vers, sizeof (vers), abfd) != sizeof (vers))
    return FALSE;

  for (i = 0; i < WASM_NUMBERED_SECTIONS; i++)
    numbered_sections[i] = NULL;

  bfd_map_over_sections (abfd, wasm_register_section, numbered_sections);

  fs.pos = bfd_tell (abfd);
  for (i = 0; i < WASM_NUMBERED_SECTIONS; i++)
    {
      sec_ptr sec = numbered_sections[i];
      bfd_size_type size;

      if (! sec)
	continue;
      size = sec->size;
      if (bfd_seek (abfd, fs.pos, SEEK_SET) != 0)
	return FALSE;
      if (! wasm_write_uleb128 (abfd, i)
	  || ! wasm_write_uleb128 (abfd, size))
	return FALSE;
      fs.pos = sec->filepos = bfd_tell (abfd);
      fs.pos += size;
    }

  fs.failed = FALSE;

  bfd_map_over_sections (abfd, wasm_compute_custom_section_file_position, &fs);

  if (fs.failed)
    return FALSE;

  abfd->output_has_begun = TRUE;

  return TRUE;
}

static bfd_boolean
wasm_set_section_contents (bfd *abfd,
			   sec_ptr section,
			   const void *location,
			   file_ptr offset,
			   bfd_size_type count)
{
  if (count == 0)
    return TRUE;

  if (! abfd->output_has_begun
      && ! wasm_compute_section_file_positions (abfd))
    return FALSE;

  if (bfd_seek (abfd, section->filepos + offset, SEEK_SET) != 0
      || bfd_bwrite (location, count, abfd) != count)
    return FALSE;

  return TRUE;
}

static bfd_boolean
wasm_write_object_contents (bfd* abfd)
{
  bfd_byte magic[] = WASM_MAGIC;
  bfd_byte vers[] = WASM_VERSION;

  if (bfd_seek (abfd, 0, SEEK_SET) != 0)
    return FALSE;

  if (bfd_bwrite (magic, sizeof (magic), abfd) != sizeof (magic)
      || bfd_bwrite (vers, sizeof (vers), abfd) != sizeof (vers))
    return FALSE;

  return TRUE;
}

static bfd_boolean
wasm_mkobject (bfd *abfd)
{
  tdata_type *tdata = (tdata_type *) bfd_alloc (abfd, sizeof (tdata_type));

  if (! tdata)
    return FALSE;

  tdata->symbols = NULL;
  tdata->symcount = 0;

  abfd->tdata.any = tdata;

  return TRUE;
}

static long
wasm_get_symtab_upper_bound (bfd *abfd)
{
  tdata_type *tdata = abfd->tdata.any;

  return (tdata->symcount + 1) * (sizeof (asymbol *));
}

static long
wasm_canonicalize_symtab (bfd *abfd, asymbol **alocation)
{
  tdata_type *tdata = abfd->tdata.any;
  size_t i;

  for (i = 0; i < tdata->symcount; i++)
    alocation[i] = &tdata->symbols[i];
  alocation[i] = NULL;

  return tdata->symcount;
}

static asymbol *
wasm_make_empty_symbol (bfd *abfd)
{
  bfd_size_type amt = sizeof (asymbol);
  asymbol *new_symbol = (asymbol *) bfd_zalloc (abfd, amt);

  if (! new_symbol)
    return NULL;
  new_symbol->the_bfd = abfd;
  return new_symbol;
}

static void
wasm_print_symbol (bfd *abfd,
		   void * filep,
		   asymbol *symbol,
		   bfd_print_symbol_type how)
{
  FILE *file = (FILE *) filep;

  switch (how)
    {
    case bfd_print_symbol_name:
      fprintf (file, "%s", symbol->name);
      break;

    default:
      bfd_print_symbol_vandf (abfd, filep, symbol);
      fprintf (file, " %-5s %s", symbol->section->name, symbol->name);
    }
}

static void
wasm_get_symbol_info (bfd *abfd ATTRIBUTE_UNUSED,
		      asymbol *symbol,
		      symbol_info *ret)
{
  bfd_symbol_info (symbol, ret);
}

/* Check whether ABFD is a WebAssembly module; if so, scan it.  */

static const bfd_target *
wasm_object_p (bfd *abfd)
{
  bfd_boolean error;

  if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
    return NULL;

  if (! wasm_read_header (abfd, &error))
    {
      bfd_set_error (bfd_error_wrong_format);
      return NULL;
    }

  if (! wasm_mkobject (abfd) || ! wasm_scan (abfd))
    return NULL;

  if (! bfd_default_set_arch_mach (abfd, bfd_arch_wasm32, 0))
    return NULL;

  if (wasm_scan_name_function_section (abfd, bfd_get_section_by_name (abfd, WASM_NAME_SECTION)))
    abfd->flags |= HAS_SYMS;

  return abfd->xvec;
}

/* BFD_JUMP_TABLE_WRITE */
#define wasm_set_arch_mach		  _bfd_generic_set_arch_mach

/* BFD_JUMP_TABLE_SYMBOLS */
#define wasm_get_symbol_version_string	  _bfd_nosymbols_get_symbol_version_string
#define wasm_bfd_is_local_label_name	   bfd_generic_is_local_label_name
#define wasm_bfd_is_target_special_symbol ((bfd_boolean (*) (bfd *, asymbol *)) bfd_false_any)
#define wasm_get_lineno			  _bfd_nosymbols_get_lineno
#define wasm_find_nearest_line		  _bfd_nosymbols_find_nearest_line
#define wasm_find_line			  _bfd_nosymbols_find_line
#define wasm_find_inliner_info		  _bfd_nosymbols_find_inliner_info
#define wasm_bfd_make_debug_symbol	  _bfd_nosymbols_bfd_make_debug_symbol
#define wasm_read_minisymbols		  _bfd_generic_read_minisymbols
#define wasm_minisymbol_to_symbol	  _bfd_generic_minisymbol_to_symbol

const bfd_target wasm_vec =
{
  "wasm",			/* Name.  */
  bfd_target_unknown_flavour,
  BFD_ENDIAN_LITTLE,
  BFD_ENDIAN_LITTLE,
  (HAS_SYMS | WP_TEXT),		/* Object flags.  */
  (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS), /* Section flags.  */
  0,				/* Leading underscore.  */
  ' ',				/* AR_pad_char.  */
  255,				/* AR_max_namelen.  */
  0,				/* Match priority.  */
  /* Routines to byte-swap various sized integers from the data sections.  */
  bfd_getl64, bfd_getl_signed_64, bfd_putl64,
  bfd_getl32, bfd_getl_signed_32, bfd_putl32,
  bfd_getl16, bfd_getl_signed_16, bfd_putl16,

  /* Routines to byte-swap various sized integers from the file headers.  */
  bfd_getl64, bfd_getl_signed_64, bfd_putl64,
  bfd_getl32, bfd_getl_signed_32, bfd_putl32,
  bfd_getl16, bfd_getl_signed_16, bfd_putl16,

  {
    _bfd_dummy_target,
    wasm_object_p,		/* bfd_check_format.  */
    _bfd_dummy_target,
    _bfd_dummy_target,
  },
  {
    bfd_false,
    wasm_mkobject,
    _bfd_generic_mkarchive,
    bfd_false,
  },
  {				/* bfd_write_contents.  */
    bfd_false,
    wasm_write_object_contents,
    _bfd_write_archive_contents,
    bfd_false,
  },

  BFD_JUMP_TABLE_GENERIC (_bfd_generic),
  BFD_JUMP_TABLE_COPY (_bfd_generic),
  BFD_JUMP_TABLE_CORE (_bfd_nocore),
  BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
  BFD_JUMP_TABLE_SYMBOLS (wasm),
  BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
  BFD_JUMP_TABLE_WRITE (wasm),
  BFD_JUMP_TABLE_LINK (_bfd_nolink),
  BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),

  NULL,

  NULL,
};