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a6be0538 1/* BFD back-end for WebAssembly modules.
fd67aa11 2 Copyright (C) 2017-2024 Free Software Foundation, Inc.
a6be0538
PC
3
4 Based on srec.c, mmo.c, and binary.c
5
6 This file is part of BFD, the Binary File Descriptor library.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 MA 02110-1301, USA. */
22
23/* The WebAssembly module format is a simple object file format
24 including up to 11 numbered sections, plus any number of named
25 "custom" sections. It is described at:
26 https://github.com/WebAssembly/design/blob/master/BinaryEncoding.md. */
27
28#include "sysdep.h"
a6be0538 29#include "bfd.h"
a6be0538
PC
30#include "libiberty.h"
31#include "libbfd.h"
32#include "wasm-module.h"
33
b9b204b3 34#include <limits.h>
b9b204b3
AM
35#ifndef CHAR_BIT
36#define CHAR_BIT 8
37#endif
38
a6be0538
PC
39typedef struct
40{
41 asymbol * symbols;
42 bfd_size_type symcount;
43} tdata_type;
44
45static const char * const wasm_numbered_sections[] =
46{
47 NULL, /* Custom section, different layout. */
48 WASM_SECTION ( 1, "type"),
49 WASM_SECTION ( 2, "import"),
50 WASM_SECTION ( 3, "function"),
51 WASM_SECTION ( 4, "table"),
52 WASM_SECTION ( 5, "memory"),
53 WASM_SECTION ( 6, "global"),
54 WASM_SECTION ( 7, "export"),
55 WASM_SECTION ( 8, "start"),
56 WASM_SECTION ( 9, "element"),
57 WASM_SECTION (10, "code"),
58 WASM_SECTION (11, "data"),
59};
60
61#define WASM_NUMBERED_SECTIONS ARRAY_SIZE (wasm_numbered_sections)
62
63/* Resolve SECTION_CODE to a section name if there is one, NULL
64 otherwise. */
65
66static const char *
67wasm_section_code_to_name (bfd_byte section_code)
68{
69 if (section_code < WASM_NUMBERED_SECTIONS)
70 return wasm_numbered_sections[section_code];
71
72 return NULL;
73}
74
75/* Translate section name NAME to a section code, or 0 if it's a
76 custom name. */
77
78static unsigned int
79wasm_section_name_to_code (const char *name)
80{
81 unsigned i;
82
83 for (i = 1; i < WASM_NUMBERED_SECTIONS; i++)
84 if (strcmp (name, wasm_numbered_sections[i]) == 0)
85 return i;
86
87 return 0;
88}
89
90/* WebAssembly LEB128 integers are sufficiently like DWARF LEB128
91 integers that we use _bfd_safe_read_leb128, but there are two
92 points of difference:
93
94 - WebAssembly requires a 32-bit value to be encoded in at most 5
95 bytes, etc.
96 - _bfd_safe_read_leb128 accepts incomplete LEB128 encodings at the
97 end of the buffer, while these are invalid in WebAssembly.
98
99 Those differences mean that we will accept some files that are
100 invalid WebAssembly. */
101
102/* Read an LEB128-encoded integer from ABFD's I/O stream, reading one
103 byte at a time. Set ERROR_RETURN if no complete integer could be
104 read, LENGTH_RETURN to the number of bytes read (including bytes in
105 incomplete numbers). SIGN means interpret the number as SLEB128. */
106
107static bfd_vma
0a1b45a2
AM
108wasm_read_leb128 (bfd *abfd,
109 bool *error_return,
110 unsigned int *length_return,
111 bool sign)
a6be0538
PC
112{
113 bfd_vma result = 0;
114 unsigned int num_read = 0;
115 unsigned int shift = 0;
116 unsigned char byte = 0;
b9b204b3 117 unsigned char lost, mask;
27c1c427 118 int status = 1;
a6be0538 119
226f9f4f 120 while (bfd_read (&byte, 1, abfd) == 1)
a6be0538
PC
121 {
122 num_read++;
123
b9b204b3 124 if (shift < CHAR_BIT * sizeof (result))
27c1c427
AM
125 {
126 result |= ((bfd_vma) (byte & 0x7f)) << shift;
b9b204b3
AM
127 /* These bits overflowed. */
128 lost = byte ^ (result >> shift);
129 /* And this is the mask of possible overflow bits. */
130 mask = 0x7f ^ ((bfd_vma) 0x7f << shift >> shift);
27c1c427
AM
131 shift += 7;
132 }
b9b204b3
AM
133 else
134 {
135 lost = byte;
136 mask = 0x7f;
137 }
138 if ((lost & mask) != (sign && (bfd_signed_vma) result < 0 ? mask : 0))
27c1c427 139 status |= 2;
a6be0538 140
a6be0538 141 if ((byte & 0x80) == 0)
07d6d2b8 142 {
27c1c427 143 status &= ~1;
b9b204b3 144 if (sign && shift < CHAR_BIT * sizeof (result) && (byte & 0x40))
27c1c427 145 result |= -((bfd_vma) 1 << shift);
07d6d2b8
AM
146 break;
147 }
a6be0538
PC
148 }
149
150 if (length_return != NULL)
151 *length_return = num_read;
152 if (error_return != NULL)
27c1c427 153 *error_return = status != 0;
a6be0538
PC
154
155 return result;
156}
157
158/* Encode an integer V as LEB128 and write it to ABFD, return TRUE on
159 success. */
160
0a1b45a2 161static bool
a6be0538
PC
162wasm_write_uleb128 (bfd *abfd, bfd_vma v)
163{
164 do
165 {
166 bfd_byte c = v & 0x7f;
167 v >>= 7;
168
169 if (v)
07d6d2b8 170 c |= 0x80;
a6be0538 171
226f9f4f 172 if (bfd_write (&c, 1, abfd) != 1)
0a1b45a2 173 return false;
a6be0538
PC
174 }
175 while (v);
176
0a1b45a2 177 return true;
a6be0538
PC
178}
179
180/* Read the LEB128 integer at P, saving it to X; at end of buffer,
181 jump to error_return. */
07d6d2b8
AM
182#define READ_LEB128(x, p, end) \
183 do \
184 { \
574ec108 185 if ((p) >= (end)) \
07d6d2b8 186 goto error_return; \
574ec108 187 (x) = _bfd_safe_read_leb128 (abfd, &(p), false, (end)); \
07d6d2b8 188 } \
a6be0538
PC
189 while (0)
190
191/* Verify the magic number at the beginning of a WebAssembly module
192 ABFD, setting ERRORPTR if there's a mismatch. */
193
0a1b45a2
AM
194static bool
195wasm_read_magic (bfd *abfd, bool *errorptr)
a6be0538
PC
196{
197 bfd_byte magic_const[SIZEOF_WASM_MAGIC] = WASM_MAGIC;
198 bfd_byte magic[SIZEOF_WASM_MAGIC];
199
226f9f4f 200 if (bfd_read (magic, sizeof (magic), abfd) == sizeof (magic)
a6be0538 201 && memcmp (magic, magic_const, sizeof (magic)) == 0)
0a1b45a2 202 return true;
a6be0538 203
0a1b45a2
AM
204 *errorptr = true;
205 return false;
a6be0538
PC
206}
207
208/* Read the version number from ABFD, returning TRUE if it's a supported
209 version. Set ERRORPTR otherwise. */
210
0a1b45a2
AM
211static bool
212wasm_read_version (bfd *abfd, bool *errorptr)
a6be0538
PC
213{
214 bfd_byte vers_const[SIZEOF_WASM_VERSION] = WASM_VERSION;
215 bfd_byte vers[SIZEOF_WASM_VERSION];
216
226f9f4f 217 if (bfd_read (vers, sizeof (vers), abfd) == sizeof (vers)
a6be0538
PC
218 /* Don't attempt to parse newer versions, which are likely to
219 require code changes. */
220 && memcmp (vers, vers_const, sizeof (vers)) == 0)
0a1b45a2 221 return true;
a6be0538 222
0a1b45a2
AM
223 *errorptr = true;
224 return false;
a6be0538
PC
225}
226
227/* Read the WebAssembly header (magic number plus version number) from
228 ABFD, setting ERRORPTR to TRUE if there is a mismatch. */
229
0a1b45a2
AM
230static bool
231wasm_read_header (bfd *abfd, bool *errorptr)
a6be0538
PC
232{
233 if (! wasm_read_magic (abfd, errorptr))
0a1b45a2 234 return false;
a6be0538
PC
235
236 if (! wasm_read_version (abfd, errorptr))
0a1b45a2 237 return false;
a6be0538 238
0a1b45a2 239 return true;
a6be0538
PC
240}
241
242/* Scan the "function" subsection of the "name" section ASECT in the
243 wasm module ABFD. Create symbols. Return TRUE on success. */
244
0a1b45a2 245static bool
a6be0538
PC
246wasm_scan_name_function_section (bfd *abfd, sec_ptr asect)
247{
248 bfd_byte *p;
249 bfd_byte *end;
250 bfd_vma payload_size;
251 bfd_vma symcount = 0;
252 tdata_type *tdata = abfd->tdata.any;
253 asymbol *symbols = NULL;
254 sec_ptr space_function_index;
1f4361a7 255 size_t amt;
a6be0538 256
a6be0538
PC
257 p = asect->contents;
258 end = asect->contents + asect->size;
259
0c0adcc5 260 if (!p)
0a1b45a2 261 return false;
a6be0538
PC
262
263 while (p < end)
264 {
265 bfd_byte subsection_code = *p++;
266 if (subsection_code == WASM_FUNCTION_SUBSECTION)
07d6d2b8 267 break;
a6be0538
PC
268
269 /* subsection_code is documented to be a varuint7, meaning that
07d6d2b8
AM
270 it has to be a single byte in the 0 - 127 range. If it isn't,
271 the spec must have changed underneath us, so give up. */
a6be0538 272 if (subsection_code & 0x80)
0a1b45a2 273 return false;
a6be0538
PC
274
275 READ_LEB128 (payload_size, p, end);
276
0c0adcc5 277 if (payload_size > (size_t) (end - p))
0a1b45a2 278 return false;
a6be0538
PC
279
280 p += payload_size;
281 }
282
283 if (p >= end)
0a1b45a2 284 return false;
a6be0538
PC
285
286 READ_LEB128 (payload_size, p, end);
287
0c0adcc5 288 if (payload_size > (size_t) (end - p))
0a1b45a2 289 return false;
a6be0538
PC
290
291 end = p + payload_size;
292
293 READ_LEB128 (symcount, p, end);
294
295 /* Sanity check: each symbol has at least two bytes. */
0c0adcc5 296 if (symcount > payload_size / 2)
0a1b45a2 297 return false;
a6be0538
PC
298
299 tdata->symcount = symcount;
300
0c0adcc5
AM
301 space_function_index
302 = bfd_make_section_with_flags (abfd, WASM_SECTION_FUNCTION_INDEX,
303 SEC_READONLY | SEC_CODE);
a6be0538 304
0c0adcc5
AM
305 if (!space_function_index)
306 space_function_index
307 = bfd_get_section_by_name (abfd, WASM_SECTION_FUNCTION_INDEX);
a6be0538 308
0c0adcc5 309 if (!space_function_index)
0a1b45a2 310 return false;
a6be0538 311
1f4361a7
AM
312 if (_bfd_mul_overflow (tdata->symcount, sizeof (asymbol), &amt))
313 {
314 bfd_set_error (bfd_error_file_too_big);
0a1b45a2 315 return false;
1f4361a7
AM
316 }
317 symbols = bfd_alloc (abfd, amt);
0c0adcc5 318 if (!symbols)
0a1b45a2 319 return false;
a6be0538
PC
320
321 for (symcount = 0; p < end && symcount < tdata->symcount; symcount++)
322 {
87993319 323 bfd_vma idx;
a6be0538
PC
324 bfd_vma len;
325 char *name;
326 asymbol *sym;
327
87993319 328 READ_LEB128 (idx, p, end);
a6be0538
PC
329 READ_LEB128 (len, p, end);
330
0c0adcc5 331 if (len > (size_t) (end - p))
07d6d2b8 332 goto error_return;
a6be0538 333
0c0adcc5
AM
334 name = bfd_alloc (abfd, len + 1);
335 if (!name)
07d6d2b8 336 goto error_return;
a6be0538
PC
337
338 memcpy (name, p, len);
0c0adcc5 339 name[len] = 0;
a6be0538
PC
340 p += len;
341
342 sym = &symbols[symcount];
343 sym->the_bfd = abfd;
344 sym->name = name;
87993319 345 sym->value = idx;
a6be0538
PC
346 sym->flags = BSF_GLOBAL | BSF_FUNCTION;
347 sym->section = space_function_index;
348 sym->udata.p = NULL;
349 }
350
351 if (symcount < tdata->symcount)
352 goto error_return;
353
354 tdata->symbols = symbols;
355 abfd->symcount = symcount;
356
0a1b45a2 357 return true;
a6be0538
PC
358
359 error_return:
cfabce5b
AM
360 if (symbols)
361 bfd_release (abfd, symbols);
d499fb89 362 tdata->symcount = 0;
0a1b45a2 363 return false;
a6be0538
PC
364}
365
366/* Read a byte from ABFD and return it, or EOF for EOF or error.
367 Set ERRORPTR on non-EOF error. */
368
369static int
0a1b45a2 370wasm_read_byte (bfd *abfd, bool *errorptr)
a6be0538
PC
371{
372 bfd_byte byte;
373
226f9f4f 374 if (bfd_read (&byte, 1, abfd) != 1)
a6be0538
PC
375 {
376 if (bfd_get_error () != bfd_error_file_truncated)
0a1b45a2 377 *errorptr = true;
a6be0538
PC
378 return EOF;
379 }
380
381 return byte;
382}
383
384/* Scan the wasm module ABFD, creating sections and symbols.
385 Return TRUE on success. */
386
0a1b45a2 387static bool
a6be0538
PC
388wasm_scan (bfd *abfd)
389{
0a1b45a2 390 bool error = false;
a6be0538
PC
391 /* Fake VMAs for now. Choose 0x80000000 as base to avoid clashes
392 with actual data addresses. */
393 bfd_vma vma = 0x80000000;
394 int section_code;
395 unsigned int bytes_read;
a6be0538
PC
396 asection *bfdsec;
397
226f9f4f 398 if (bfd_seek (abfd, 0, SEEK_SET) != 0)
a6be0538
PC
399 goto error_return;
400
0c0adcc5 401 if (!wasm_read_header (abfd, &error))
a6be0538
PC
402 goto error_return;
403
404 while ((section_code = wasm_read_byte (abfd, &error)) != EOF)
405 {
406 if (section_code != 0)
07d6d2b8
AM
407 {
408 const char *sname = wasm_section_code_to_name (section_code);
409
0c0adcc5 410 if (!sname)
07d6d2b8
AM
411 goto error_return;
412
0c0adcc5
AM
413 bfdsec = bfd_make_section_anyway_with_flags (abfd, sname,
414 SEC_HAS_CONTENTS);
07d6d2b8
AM
415 if (bfdsec == NULL)
416 goto error_return;
07d6d2b8 417
0a1b45a2 418 bfdsec->size = wasm_read_leb128 (abfd, &error, &bytes_read, false);
07d6d2b8
AM
419 if (error)
420 goto error_return;
07d6d2b8 421 }
a6be0538 422 else
07d6d2b8
AM
423 {
424 bfd_vma payload_len;
07d6d2b8 425 bfd_vma namelen;
0c0adcc5 426 char *name;
07d6d2b8 427 char *prefix = WASM_SECTION_PREFIX;
0c0adcc5 428 size_t prefixlen = strlen (prefix);
2f57795b 429 ufile_ptr filesize;
07d6d2b8 430
0a1b45a2 431 payload_len = wasm_read_leb128 (abfd, &error, &bytes_read, false);
07d6d2b8
AM
432 if (error)
433 goto error_return;
0a1b45a2 434 namelen = wasm_read_leb128 (abfd, &error, &bytes_read, false);
2f57795b
AM
435 if (error || bytes_read > payload_len
436 || namelen > payload_len - bytes_read)
07d6d2b8 437 goto error_return;
2f57795b
AM
438 payload_len -= namelen + bytes_read;
439 filesize = bfd_get_file_size (abfd);
440 if (filesize != 0 && namelen > filesize)
441 {
442 bfd_set_error (bfd_error_file_truncated);
0a1b45a2 443 return false;
2f57795b 444 }
0c0adcc5
AM
445 name = bfd_alloc (abfd, namelen + prefixlen + 1);
446 if (!name)
07d6d2b8 447 goto error_return;
0c0adcc5 448 memcpy (name, prefix, prefixlen);
226f9f4f 449 if (bfd_read (name + prefixlen, namelen, abfd) != namelen)
a6be0538 450 goto error_return;
0c0adcc5 451 name[prefixlen + namelen] = 0;
a6be0538 452
0c0adcc5
AM
453 bfdsec = bfd_make_section_anyway_with_flags (abfd, name,
454 SEC_HAS_CONTENTS);
07d6d2b8
AM
455 if (bfdsec == NULL)
456 goto error_return;
a6be0538 457
2f57795b 458 bfdsec->size = payload_len;
07d6d2b8 459 }
a6be0538 460
2f57795b
AM
461 bfdsec->vma = vma;
462 bfdsec->lma = vma;
463 bfdsec->alignment_power = 0;
464 bfdsec->filepos = bfd_tell (abfd);
a6be0538 465 if (bfdsec->size != 0)
07d6d2b8 466 {
2bb3687b
AM
467 bfdsec->contents = _bfd_alloc_and_read (abfd, bfdsec->size,
468 bfdsec->size);
0c0adcc5 469 if (!bfdsec->contents)
07d6d2b8 470 goto error_return;
07d6d2b8 471 }
a6be0538
PC
472
473 vma += bfdsec->size;
474 }
475
476 /* Make sure we're at actual EOF. There's no indication in the
477 WebAssembly format of how long the file is supposed to be. */
478 if (error)
479 goto error_return;
480
0a1b45a2 481 return true;
a6be0538
PC
482
483 error_return:
0a1b45a2 484 return false;
a6be0538
PC
485}
486
487/* Put a numbered section ASECT of ABFD into the table of numbered
488 sections pointed to by FSARG. */
489
490static void
491wasm_register_section (bfd *abfd ATTRIBUTE_UNUSED,
07d6d2b8 492 asection *asect,
a6be0538
PC
493 void *fsarg)
494{
495 sec_ptr *numbered_sections = fsarg;
87993319 496 int idx = wasm_section_name_to_code (asect->name);
a6be0538 497
87993319 498 if (idx == 0)
a6be0538
PC
499 return;
500
87993319 501 numbered_sections[idx] = asect;
a6be0538
PC
502}
503
504struct compute_section_arg
505{
506 bfd_vma pos;
0a1b45a2 507 bool failed;
a6be0538
PC
508};
509
510/* Compute the file position of ABFD's section ASECT. FSARG is a
511 pointer to the current file position.
512
513 We allow section names of the form .wasm.id to encode the numbered
514 section with ID id, if it exists; otherwise, a custom section with
515 ID "id" is produced. Arbitrary section names are for sections that
516 are assumed already to contain a section header; those are appended
517 to the WebAssembly module verbatim. */
518
519static void
520wasm_compute_custom_section_file_position (bfd *abfd,
521 sec_ptr asect,
07d6d2b8 522 void *fsarg)
a6be0538
PC
523{
524 struct compute_section_arg *fs = fsarg;
87993319 525 int idx;
a6be0538
PC
526
527 if (fs->failed)
528 return;
529
87993319 530 idx = wasm_section_name_to_code (asect->name);
a6be0538 531
87993319 532 if (idx != 0)
a6be0538
PC
533 return;
534
08dedd66 535 if (startswith (asect->name, WASM_SECTION_PREFIX))
a6be0538
PC
536 {
537 const char *name = asect->name + strlen (WASM_SECTION_PREFIX);
538 bfd_size_type payload_len = asect->size;
539 bfd_size_type name_len = strlen (name);
540 bfd_size_type nl = name_len;
541
542 payload_len += name_len;
543
544 do
07d6d2b8
AM
545 {
546 payload_len++;
547 nl >>= 7;
548 }
a6be0538
PC
549 while (nl);
550
e416bd75
AM
551 if (bfd_seek (abfd, fs->pos, SEEK_SET) != 0
552 || ! wasm_write_uleb128 (abfd, 0)
07d6d2b8
AM
553 || ! wasm_write_uleb128 (abfd, payload_len)
554 || ! wasm_write_uleb128 (abfd, name_len)
226f9f4f 555 || bfd_write (name, name_len, abfd) != name_len)
07d6d2b8 556 goto error_return;
a6be0538
PC
557 fs->pos = asect->filepos = bfd_tell (abfd);
558 }
559 else
560 {
561 asect->filepos = fs->pos;
562 }
563
564
565 fs->pos += asect->size;
566 return;
567
568 error_return:
0a1b45a2 569 fs->failed = true;
a6be0538
PC
570}
571
572/* Compute the file positions for the sections of ABFD. Currently,
573 this writes all numbered sections first, in order, then all custom
574 sections, in section order.
575
576 The spec says that the numbered sections must appear in order of
577 their ids, but custom sections can appear in any position and any
578 order, and more than once. FIXME: support that. */
579
0a1b45a2 580static bool
a6be0538
PC
581wasm_compute_section_file_positions (bfd *abfd)
582{
583 bfd_byte magic[SIZEOF_WASM_MAGIC] = WASM_MAGIC;
584 bfd_byte vers[SIZEOF_WASM_VERSION] = WASM_VERSION;
585 sec_ptr numbered_sections[WASM_NUMBERED_SECTIONS];
586 struct compute_section_arg fs;
587 unsigned int i;
588
e416bd75
AM
589 if (bfd_seek (abfd, (bfd_vma) 0, SEEK_SET) != 0
590 || bfd_write (magic, sizeof (magic), abfd) != (sizeof magic)
226f9f4f 591 || bfd_write (vers, sizeof (vers), abfd) != sizeof (vers))
0a1b45a2 592 return false;
a6be0538
PC
593
594 for (i = 0; i < WASM_NUMBERED_SECTIONS; i++)
595 numbered_sections[i] = NULL;
596
597 bfd_map_over_sections (abfd, wasm_register_section, numbered_sections);
598
599 fs.pos = bfd_tell (abfd);
600 for (i = 0; i < WASM_NUMBERED_SECTIONS; i++)
601 {
602 sec_ptr sec = numbered_sections[i];
603 bfd_size_type size;
604
605 if (! sec)
07d6d2b8 606 continue;
a6be0538
PC
607 size = sec->size;
608 if (bfd_seek (abfd, fs.pos, SEEK_SET) != 0)
0a1b45a2 609 return false;
a6be0538 610 if (! wasm_write_uleb128 (abfd, i)
07d6d2b8 611 || ! wasm_write_uleb128 (abfd, size))
0a1b45a2 612 return false;
a6be0538
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613 fs.pos = sec->filepos = bfd_tell (abfd);
614 fs.pos += size;
615 }
616
0a1b45a2 617 fs.failed = false;
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618
619 bfd_map_over_sections (abfd, wasm_compute_custom_section_file_position, &fs);
620
621 if (fs.failed)
0a1b45a2 622 return false;
a6be0538 623
0a1b45a2 624 abfd->output_has_begun = true;
a6be0538 625
0a1b45a2 626 return true;
a6be0538
PC
627}
628
0a1b45a2 629static bool
a6be0538 630wasm_set_section_contents (bfd *abfd,
07d6d2b8
AM
631 sec_ptr section,
632 const void *location,
633 file_ptr offset,
634 bfd_size_type count)
a6be0538
PC
635{
636 if (count == 0)
0a1b45a2 637 return true;
a6be0538
PC
638
639 if (! abfd->output_has_begun
640 && ! wasm_compute_section_file_positions (abfd))
0a1b45a2 641 return false;
a6be0538
PC
642
643 if (bfd_seek (abfd, section->filepos + offset, SEEK_SET) != 0
226f9f4f 644 || bfd_write (location, count, abfd) != count)
0a1b45a2 645 return false;
a6be0538 646
0a1b45a2 647 return true;
a6be0538
PC
648}
649
0a1b45a2 650static bool
a6be0538
PC
651wasm_write_object_contents (bfd* abfd)
652{
653 bfd_byte magic[] = WASM_MAGIC;
654 bfd_byte vers[] = WASM_VERSION;
655
656 if (bfd_seek (abfd, 0, SEEK_SET) != 0)
0a1b45a2 657 return false;
a6be0538 658
226f9f4f
AM
659 if (bfd_write (magic, sizeof (magic), abfd) != sizeof (magic)
660 || bfd_write (vers, sizeof (vers), abfd) != sizeof (vers))
0a1b45a2 661 return false;
a6be0538 662
0a1b45a2 663 return true;
a6be0538
PC
664}
665
0a1b45a2 666static bool
a6be0538
PC
667wasm_mkobject (bfd *abfd)
668{
669 tdata_type *tdata = (tdata_type *) bfd_alloc (abfd, sizeof (tdata_type));
670
671 if (! tdata)
0a1b45a2 672 return false;
a6be0538
PC
673
674 tdata->symbols = NULL;
675 tdata->symcount = 0;
676
677 abfd->tdata.any = tdata;
678
0a1b45a2 679 return true;
a6be0538
PC
680}
681
682static long
683wasm_get_symtab_upper_bound (bfd *abfd)
684{
685 tdata_type *tdata = abfd->tdata.any;
686
687 return (tdata->symcount + 1) * (sizeof (asymbol *));
688}
689
690static long
691wasm_canonicalize_symtab (bfd *abfd, asymbol **alocation)
692{
693 tdata_type *tdata = abfd->tdata.any;
694 size_t i;
695
696 for (i = 0; i < tdata->symcount; i++)
697 alocation[i] = &tdata->symbols[i];
698 alocation[i] = NULL;
699
700 return tdata->symcount;
701}
702
703static asymbol *
704wasm_make_empty_symbol (bfd *abfd)
705{
986f0783 706 size_t amt = sizeof (asymbol);
a6be0538
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707 asymbol *new_symbol = (asymbol *) bfd_zalloc (abfd, amt);
708
709 if (! new_symbol)
710 return NULL;
711 new_symbol->the_bfd = abfd;
712 return new_symbol;
713}
714
715static void
716wasm_print_symbol (bfd *abfd,
07d6d2b8
AM
717 void * filep,
718 asymbol *symbol,
719 bfd_print_symbol_type how)
a6be0538
PC
720{
721 FILE *file = (FILE *) filep;
722
723 switch (how)
724 {
725 case bfd_print_symbol_name:
726 fprintf (file, "%s", symbol->name);
727 break;
728
729 default:
730 bfd_print_symbol_vandf (abfd, filep, symbol);
731 fprintf (file, " %-5s %s", symbol->section->name, symbol->name);
732 }
733}
734
735static void
736wasm_get_symbol_info (bfd *abfd ATTRIBUTE_UNUSED,
07d6d2b8
AM
737 asymbol *symbol,
738 symbol_info *ret)
a6be0538
PC
739{
740 bfd_symbol_info (symbol, ret);
741}
742
743/* Check whether ABFD is a WebAssembly module; if so, scan it. */
744
cb001c0d 745static bfd_cleanup
a6be0538
PC
746wasm_object_p (bfd *abfd)
747{
0a1b45a2 748 bool error;
0c0adcc5 749 asection *s;
a6be0538 750
226f9f4f 751 if (bfd_seek (abfd, 0, SEEK_SET) != 0)
a6be0538
PC
752 return NULL;
753
0c0adcc5 754 if (!wasm_read_header (abfd, &error))
a6be0538
PC
755 {
756 bfd_set_error (bfd_error_wrong_format);
757 return NULL;
758 }
759
0c0adcc5 760 if (!wasm_mkobject (abfd))
a6be0538
PC
761 return NULL;
762
0c0adcc5
AM
763 if (!wasm_scan (abfd)
764 || !bfd_default_set_arch_mach (abfd, bfd_arch_wasm32, 0))
765 {
766 bfd_release (abfd, abfd->tdata.any);
767 abfd->tdata.any = NULL;
768 return NULL;
769 }
a6be0538 770
0c0adcc5
AM
771 s = bfd_get_section_by_name (abfd, WASM_NAME_SECTION);
772 if (s != NULL && wasm_scan_name_function_section (abfd, s))
a6be0538
PC
773 abfd->flags |= HAS_SYMS;
774
cb001c0d 775 return _bfd_no_cleanup;
a6be0538
PC
776}
777
778/* BFD_JUMP_TABLE_WRITE */
07d6d2b8 779#define wasm_set_arch_mach _bfd_generic_set_arch_mach
a6be0538
PC
780
781/* BFD_JUMP_TABLE_SYMBOLS */
07d6d2b8
AM
782#define wasm_get_symbol_version_string _bfd_nosymbols_get_symbol_version_string
783#define wasm_bfd_is_local_label_name bfd_generic_is_local_label_name
d00dd7dc 784#define wasm_bfd_is_target_special_symbol _bfd_bool_bfd_asymbol_false
07d6d2b8
AM
785#define wasm_get_lineno _bfd_nosymbols_get_lineno
786#define wasm_find_nearest_line _bfd_nosymbols_find_nearest_line
6e7a29c7 787#define wasm_find_nearest_line_with_alt _bfd_nosymbols_find_nearest_line_with_alt
07d6d2b8
AM
788#define wasm_find_line _bfd_nosymbols_find_line
789#define wasm_find_inliner_info _bfd_nosymbols_find_inliner_info
790#define wasm_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
791#define wasm_read_minisymbols _bfd_generic_read_minisymbols
792#define wasm_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol
a6be0538
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793
794const bfd_target wasm_vec =
795{
07d6d2b8 796 "wasm", /* Name. */
a6be0538
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797 bfd_target_unknown_flavour,
798 BFD_ENDIAN_LITTLE,
799 BFD_ENDIAN_LITTLE,
800 (HAS_SYMS | WP_TEXT), /* Object flags. */
801 (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS), /* Section flags. */
07d6d2b8
AM
802 0, /* Leading underscore. */
803 ' ', /* AR_pad_char. */
804 255, /* AR_max_namelen. */
a6be0538 805 0, /* Match priority. */
d1bcae83 806 TARGET_KEEP_UNUSED_SECTION_SYMBOLS, /* keep unused section symbols. */
a6be0538
PC
807 /* Routines to byte-swap various sized integers from the data sections. */
808 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
809 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
810 bfd_getl16, bfd_getl_signed_16, bfd_putl16,
811
812 /* Routines to byte-swap various sized integers from the file headers. */
813 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
814 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
815 bfd_getl16, bfd_getl_signed_16, bfd_putl16,
816
817 {
818 _bfd_dummy_target,
819 wasm_object_p, /* bfd_check_format. */
820 _bfd_dummy_target,
821 _bfd_dummy_target,
822 },
823 {
d00dd7dc 824 _bfd_bool_bfd_false_error,
a6be0538
PC
825 wasm_mkobject,
826 _bfd_generic_mkarchive,
d00dd7dc 827 _bfd_bool_bfd_false_error,
a6be0538
PC
828 },
829 { /* bfd_write_contents. */
d00dd7dc 830 _bfd_bool_bfd_false_error,
a6be0538
PC
831 wasm_write_object_contents,
832 _bfd_write_archive_contents,
d00dd7dc 833 _bfd_bool_bfd_false_error,
a6be0538
PC
834 },
835
836 BFD_JUMP_TABLE_GENERIC (_bfd_generic),
837 BFD_JUMP_TABLE_COPY (_bfd_generic),
838 BFD_JUMP_TABLE_CORE (_bfd_nocore),
839 BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
840 BFD_JUMP_TABLE_SYMBOLS (wasm),
841 BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
842 BFD_JUMP_TABLE_WRITE (wasm),
843 BFD_JUMP_TABLE_LINK (_bfd_nolink),
844 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
845
846 NULL,
847
848 NULL,
849};