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a6be0538 | 1 | /* BFD back-end for WebAssembly modules. |
b3adc24a | 2 | Copyright (C) 2017-2020 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" | |
29 | #include "alloca-conf.h" | |
30 | #include "bfd.h" | |
a6be0538 | 31 | #include <limits.h> |
a6be0538 PC |
32 | #include "libiberty.h" |
33 | #include "libbfd.h" | |
34 | #include "wasm-module.h" | |
35 | ||
36 | typedef struct | |
37 | { | |
38 | asymbol * symbols; | |
39 | bfd_size_type symcount; | |
40 | } tdata_type; | |
41 | ||
42 | static const char * const wasm_numbered_sections[] = | |
43 | { | |
44 | NULL, /* Custom section, different layout. */ | |
45 | WASM_SECTION ( 1, "type"), | |
46 | WASM_SECTION ( 2, "import"), | |
47 | WASM_SECTION ( 3, "function"), | |
48 | WASM_SECTION ( 4, "table"), | |
49 | WASM_SECTION ( 5, "memory"), | |
50 | WASM_SECTION ( 6, "global"), | |
51 | WASM_SECTION ( 7, "export"), | |
52 | WASM_SECTION ( 8, "start"), | |
53 | WASM_SECTION ( 9, "element"), | |
54 | WASM_SECTION (10, "code"), | |
55 | WASM_SECTION (11, "data"), | |
56 | }; | |
57 | ||
58 | #define WASM_NUMBERED_SECTIONS ARRAY_SIZE (wasm_numbered_sections) | |
59 | ||
60 | /* Resolve SECTION_CODE to a section name if there is one, NULL | |
61 | otherwise. */ | |
62 | ||
63 | static const char * | |
64 | wasm_section_code_to_name (bfd_byte section_code) | |
65 | { | |
66 | if (section_code < WASM_NUMBERED_SECTIONS) | |
67 | return wasm_numbered_sections[section_code]; | |
68 | ||
69 | return NULL; | |
70 | } | |
71 | ||
72 | /* Translate section name NAME to a section code, or 0 if it's a | |
73 | custom name. */ | |
74 | ||
75 | static unsigned int | |
76 | wasm_section_name_to_code (const char *name) | |
77 | { | |
78 | unsigned i; | |
79 | ||
80 | for (i = 1; i < WASM_NUMBERED_SECTIONS; i++) | |
81 | if (strcmp (name, wasm_numbered_sections[i]) == 0) | |
82 | return i; | |
83 | ||
84 | return 0; | |
85 | } | |
86 | ||
87 | /* WebAssembly LEB128 integers are sufficiently like DWARF LEB128 | |
88 | integers that we use _bfd_safe_read_leb128, but there are two | |
89 | points of difference: | |
90 | ||
91 | - WebAssembly requires a 32-bit value to be encoded in at most 5 | |
92 | bytes, etc. | |
93 | - _bfd_safe_read_leb128 accepts incomplete LEB128 encodings at the | |
94 | end of the buffer, while these are invalid in WebAssembly. | |
95 | ||
96 | Those differences mean that we will accept some files that are | |
97 | invalid WebAssembly. */ | |
98 | ||
99 | /* Read an LEB128-encoded integer from ABFD's I/O stream, reading one | |
100 | byte at a time. Set ERROR_RETURN if no complete integer could be | |
101 | read, LENGTH_RETURN to the number of bytes read (including bytes in | |
102 | incomplete numbers). SIGN means interpret the number as SLEB128. */ | |
103 | ||
104 | static bfd_vma | |
07d6d2b8 AM |
105 | wasm_read_leb128 (bfd * abfd, |
106 | bfd_boolean * error_return, | |
107 | unsigned int * length_return, | |
108 | bfd_boolean sign) | |
a6be0538 PC |
109 | { |
110 | bfd_vma result = 0; | |
111 | unsigned int num_read = 0; | |
112 | unsigned int shift = 0; | |
113 | unsigned char byte = 0; | |
27c1c427 | 114 | int status = 1; |
a6be0538 PC |
115 | |
116 | while (bfd_bread (&byte, 1, abfd) == 1) | |
117 | { | |
118 | num_read++; | |
119 | ||
27c1c427 AM |
120 | if (shift < sizeof (result) * 8) |
121 | { | |
122 | result |= ((bfd_vma) (byte & 0x7f)) << shift; | |
123 | if ((result >> shift) != (byte & 0x7f)) | |
124 | /* Overflow. */ | |
125 | status |= 2; | |
126 | shift += 7; | |
127 | } | |
128 | else if ((byte & 0x7f) != 0) | |
129 | status |= 2; | |
a6be0538 | 130 | |
a6be0538 | 131 | if ((byte & 0x80) == 0) |
07d6d2b8 | 132 | { |
27c1c427 AM |
133 | status &= ~1; |
134 | if (sign && (shift < 8 * sizeof (result)) && (byte & 0x40)) | |
135 | result |= -((bfd_vma) 1 << shift); | |
07d6d2b8 AM |
136 | break; |
137 | } | |
a6be0538 PC |
138 | } |
139 | ||
140 | if (length_return != NULL) | |
141 | *length_return = num_read; | |
142 | if (error_return != NULL) | |
27c1c427 | 143 | *error_return = status != 0; |
a6be0538 PC |
144 | |
145 | return result; | |
146 | } | |
147 | ||
148 | /* Encode an integer V as LEB128 and write it to ABFD, return TRUE on | |
149 | success. */ | |
150 | ||
151 | static bfd_boolean | |
152 | wasm_write_uleb128 (bfd *abfd, bfd_vma v) | |
153 | { | |
154 | do | |
155 | { | |
156 | bfd_byte c = v & 0x7f; | |
157 | v >>= 7; | |
158 | ||
159 | if (v) | |
07d6d2b8 | 160 | c |= 0x80; |
a6be0538 PC |
161 | |
162 | if (bfd_bwrite (&c, 1, abfd) != 1) | |
07d6d2b8 | 163 | return FALSE; |
a6be0538 PC |
164 | } |
165 | while (v); | |
166 | ||
167 | return TRUE; | |
168 | } | |
169 | ||
170 | /* Read the LEB128 integer at P, saving it to X; at end of buffer, | |
171 | jump to error_return. */ | |
07d6d2b8 AM |
172 | #define READ_LEB128(x, p, end) \ |
173 | do \ | |
174 | { \ | |
175 | unsigned int length_read; \ | |
176 | (x) = _bfd_safe_read_leb128 (abfd, (p), &length_read, \ | |
177 | FALSE, (end)); \ | |
178 | (p) += length_read; \ | |
179 | if (length_read == 0) \ | |
180 | goto error_return; \ | |
181 | } \ | |
a6be0538 PC |
182 | while (0) |
183 | ||
184 | /* Verify the magic number at the beginning of a WebAssembly module | |
185 | ABFD, setting ERRORPTR if there's a mismatch. */ | |
186 | ||
187 | static bfd_boolean | |
188 | wasm_read_magic (bfd *abfd, bfd_boolean *errorptr) | |
189 | { | |
190 | bfd_byte magic_const[SIZEOF_WASM_MAGIC] = WASM_MAGIC; | |
191 | bfd_byte magic[SIZEOF_WASM_MAGIC]; | |
192 | ||
193 | if (bfd_bread (magic, sizeof (magic), abfd) == sizeof (magic) | |
194 | && memcmp (magic, magic_const, sizeof (magic)) == 0) | |
195 | return TRUE; | |
196 | ||
197 | *errorptr = TRUE; | |
198 | return FALSE; | |
199 | } | |
200 | ||
201 | /* Read the version number from ABFD, returning TRUE if it's a supported | |
202 | version. Set ERRORPTR otherwise. */ | |
203 | ||
204 | static bfd_boolean | |
205 | wasm_read_version (bfd *abfd, bfd_boolean *errorptr) | |
206 | { | |
207 | bfd_byte vers_const[SIZEOF_WASM_VERSION] = WASM_VERSION; | |
208 | bfd_byte vers[SIZEOF_WASM_VERSION]; | |
209 | ||
210 | if (bfd_bread (vers, sizeof (vers), abfd) == sizeof (vers) | |
211 | /* Don't attempt to parse newer versions, which are likely to | |
212 | require code changes. */ | |
213 | && memcmp (vers, vers_const, sizeof (vers)) == 0) | |
214 | return TRUE; | |
215 | ||
216 | *errorptr = TRUE; | |
217 | return FALSE; | |
218 | } | |
219 | ||
220 | /* Read the WebAssembly header (magic number plus version number) from | |
221 | ABFD, setting ERRORPTR to TRUE if there is a mismatch. */ | |
222 | ||
223 | static bfd_boolean | |
224 | wasm_read_header (bfd *abfd, bfd_boolean *errorptr) | |
225 | { | |
226 | if (! wasm_read_magic (abfd, errorptr)) | |
227 | return FALSE; | |
228 | ||
229 | if (! wasm_read_version (abfd, errorptr)) | |
230 | return FALSE; | |
231 | ||
232 | return TRUE; | |
233 | } | |
234 | ||
235 | /* Scan the "function" subsection of the "name" section ASECT in the | |
236 | wasm module ABFD. Create symbols. Return TRUE on success. */ | |
237 | ||
238 | static bfd_boolean | |
239 | wasm_scan_name_function_section (bfd *abfd, sec_ptr asect) | |
240 | { | |
241 | bfd_byte *p; | |
242 | bfd_byte *end; | |
243 | bfd_vma payload_size; | |
244 | bfd_vma symcount = 0; | |
245 | tdata_type *tdata = abfd->tdata.any; | |
246 | asymbol *symbols = NULL; | |
247 | sec_ptr space_function_index; | |
1f4361a7 | 248 | size_t amt; |
a6be0538 | 249 | |
a6be0538 PC |
250 | p = asect->contents; |
251 | end = asect->contents + asect->size; | |
252 | ||
0c0adcc5 | 253 | if (!p) |
a6be0538 PC |
254 | return FALSE; |
255 | ||
256 | while (p < end) | |
257 | { | |
258 | bfd_byte subsection_code = *p++; | |
259 | if (subsection_code == WASM_FUNCTION_SUBSECTION) | |
07d6d2b8 | 260 | break; |
a6be0538 PC |
261 | |
262 | /* subsection_code is documented to be a varuint7, meaning that | |
07d6d2b8 AM |
263 | it has to be a single byte in the 0 - 127 range. If it isn't, |
264 | the spec must have changed underneath us, so give up. */ | |
a6be0538 | 265 | if (subsection_code & 0x80) |
07d6d2b8 | 266 | return FALSE; |
a6be0538 PC |
267 | |
268 | READ_LEB128 (payload_size, p, end); | |
269 | ||
0c0adcc5 | 270 | if (payload_size > (size_t) (end - p)) |
07d6d2b8 | 271 | return FALSE; |
a6be0538 PC |
272 | |
273 | p += payload_size; | |
274 | } | |
275 | ||
276 | if (p >= end) | |
277 | return FALSE; | |
278 | ||
279 | READ_LEB128 (payload_size, p, end); | |
280 | ||
0c0adcc5 | 281 | if (payload_size > (size_t) (end - p)) |
a6be0538 PC |
282 | return FALSE; |
283 | ||
284 | end = p + payload_size; | |
285 | ||
286 | READ_LEB128 (symcount, p, end); | |
287 | ||
288 | /* Sanity check: each symbol has at least two bytes. */ | |
0c0adcc5 | 289 | if (symcount > payload_size / 2) |
a6be0538 PC |
290 | return FALSE; |
291 | ||
292 | tdata->symcount = symcount; | |
293 | ||
0c0adcc5 AM |
294 | space_function_index |
295 | = bfd_make_section_with_flags (abfd, WASM_SECTION_FUNCTION_INDEX, | |
296 | SEC_READONLY | SEC_CODE); | |
a6be0538 | 297 | |
0c0adcc5 AM |
298 | if (!space_function_index) |
299 | space_function_index | |
300 | = bfd_get_section_by_name (abfd, WASM_SECTION_FUNCTION_INDEX); | |
a6be0538 | 301 | |
0c0adcc5 | 302 | if (!space_function_index) |
a6be0538 PC |
303 | return FALSE; |
304 | ||
1f4361a7 AM |
305 | if (_bfd_mul_overflow (tdata->symcount, sizeof (asymbol), &amt)) |
306 | { | |
307 | bfd_set_error (bfd_error_file_too_big); | |
308 | return FALSE; | |
309 | } | |
310 | symbols = bfd_alloc (abfd, amt); | |
0c0adcc5 | 311 | if (!symbols) |
a6be0538 PC |
312 | return FALSE; |
313 | ||
314 | for (symcount = 0; p < end && symcount < tdata->symcount; symcount++) | |
315 | { | |
87993319 | 316 | bfd_vma idx; |
a6be0538 PC |
317 | bfd_vma len; |
318 | char *name; | |
319 | asymbol *sym; | |
320 | ||
87993319 | 321 | READ_LEB128 (idx, p, end); |
a6be0538 PC |
322 | READ_LEB128 (len, p, end); |
323 | ||
0c0adcc5 | 324 | if (len > (size_t) (end - p)) |
07d6d2b8 | 325 | goto error_return; |
a6be0538 | 326 | |
0c0adcc5 AM |
327 | name = bfd_alloc (abfd, len + 1); |
328 | if (!name) | |
07d6d2b8 | 329 | goto error_return; |
a6be0538 PC |
330 | |
331 | memcpy (name, p, len); | |
0c0adcc5 | 332 | name[len] = 0; |
a6be0538 PC |
333 | p += len; |
334 | ||
335 | sym = &symbols[symcount]; | |
336 | sym->the_bfd = abfd; | |
337 | sym->name = name; | |
87993319 | 338 | sym->value = idx; |
a6be0538 PC |
339 | sym->flags = BSF_GLOBAL | BSF_FUNCTION; |
340 | sym->section = space_function_index; | |
341 | sym->udata.p = NULL; | |
342 | } | |
343 | ||
344 | if (symcount < tdata->symcount) | |
345 | goto error_return; | |
346 | ||
347 | tdata->symbols = symbols; | |
348 | abfd->symcount = symcount; | |
349 | ||
350 | return TRUE; | |
351 | ||
352 | error_return: | |
a6be0538 PC |
353 | bfd_release (abfd, symbols); |
354 | return FALSE; | |
355 | } | |
356 | ||
357 | /* Read a byte from ABFD and return it, or EOF for EOF or error. | |
358 | Set ERRORPTR on non-EOF error. */ | |
359 | ||
360 | static int | |
361 | wasm_read_byte (bfd *abfd, bfd_boolean *errorptr) | |
362 | { | |
363 | bfd_byte byte; | |
364 | ||
365 | if (bfd_bread (&byte, (bfd_size_type) 1, abfd) != 1) | |
366 | { | |
367 | if (bfd_get_error () != bfd_error_file_truncated) | |
07d6d2b8 | 368 | *errorptr = TRUE; |
a6be0538 PC |
369 | return EOF; |
370 | } | |
371 | ||
372 | return byte; | |
373 | } | |
374 | ||
375 | /* Scan the wasm module ABFD, creating sections and symbols. | |
376 | Return TRUE on success. */ | |
377 | ||
378 | static bfd_boolean | |
379 | wasm_scan (bfd *abfd) | |
380 | { | |
381 | bfd_boolean error = FALSE; | |
382 | /* Fake VMAs for now. Choose 0x80000000 as base to avoid clashes | |
383 | with actual data addresses. */ | |
384 | bfd_vma vma = 0x80000000; | |
385 | int section_code; | |
386 | unsigned int bytes_read; | |
a6be0538 PC |
387 | asection *bfdsec; |
388 | ||
389 | if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0) | |
390 | goto error_return; | |
391 | ||
0c0adcc5 | 392 | if (!wasm_read_header (abfd, &error)) |
a6be0538 PC |
393 | goto error_return; |
394 | ||
395 | while ((section_code = wasm_read_byte (abfd, &error)) != EOF) | |
396 | { | |
397 | if (section_code != 0) | |
07d6d2b8 AM |
398 | { |
399 | const char *sname = wasm_section_code_to_name (section_code); | |
400 | ||
0c0adcc5 | 401 | if (!sname) |
07d6d2b8 AM |
402 | goto error_return; |
403 | ||
0c0adcc5 AM |
404 | bfdsec = bfd_make_section_anyway_with_flags (abfd, sname, |
405 | SEC_HAS_CONTENTS); | |
07d6d2b8 AM |
406 | if (bfdsec == NULL) |
407 | goto error_return; | |
07d6d2b8 AM |
408 | |
409 | bfdsec->vma = vma; | |
410 | bfdsec->lma = vma; | |
411 | bfdsec->size = wasm_read_leb128 (abfd, &error, &bytes_read, FALSE); | |
412 | if (error) | |
413 | goto error_return; | |
414 | bfdsec->filepos = bfd_tell (abfd); | |
415 | bfdsec->alignment_power = 0; | |
416 | } | |
a6be0538 | 417 | else |
07d6d2b8 AM |
418 | { |
419 | bfd_vma payload_len; | |
420 | file_ptr section_start; | |
421 | bfd_vma namelen; | |
0c0adcc5 | 422 | char *name; |
07d6d2b8 | 423 | char *prefix = WASM_SECTION_PREFIX; |
0c0adcc5 | 424 | size_t prefixlen = strlen (prefix); |
07d6d2b8 AM |
425 | |
426 | payload_len = wasm_read_leb128 (abfd, &error, &bytes_read, FALSE); | |
427 | if (error) | |
428 | goto error_return; | |
429 | section_start = bfd_tell (abfd); | |
430 | namelen = wasm_read_leb128 (abfd, &error, &bytes_read, FALSE); | |
431 | if (error || namelen > payload_len) | |
432 | goto error_return; | |
0c0adcc5 AM |
433 | name = bfd_alloc (abfd, namelen + prefixlen + 1); |
434 | if (!name) | |
07d6d2b8 | 435 | goto error_return; |
0c0adcc5 AM |
436 | memcpy (name, prefix, prefixlen); |
437 | if (bfd_bread (name + prefixlen, namelen, abfd) != namelen) | |
a6be0538 | 438 | goto error_return; |
0c0adcc5 | 439 | name[prefixlen + namelen] = 0; |
a6be0538 | 440 | |
0c0adcc5 AM |
441 | bfdsec = bfd_make_section_anyway_with_flags (abfd, name, |
442 | SEC_HAS_CONTENTS); | |
07d6d2b8 AM |
443 | if (bfdsec == NULL) |
444 | goto error_return; | |
a6be0538 | 445 | |
07d6d2b8 AM |
446 | bfdsec->vma = vma; |
447 | bfdsec->lma = vma; | |
448 | bfdsec->filepos = bfd_tell (abfd); | |
449 | bfdsec->size = section_start + payload_len - bfdsec->filepos; | |
450 | bfdsec->alignment_power = 0; | |
451 | } | |
a6be0538 PC |
452 | |
453 | if (bfdsec->size != 0) | |
07d6d2b8 | 454 | { |
0c0adcc5 AM |
455 | bfdsec->contents = bfd_alloc (abfd, bfdsec->size); |
456 | if (!bfdsec->contents) | |
07d6d2b8 | 457 | goto error_return; |
a6be0538 | 458 | |
07d6d2b8 | 459 | if (bfd_bread (bfdsec->contents, bfdsec->size, abfd) != bfdsec->size) |
a6be0538 | 460 | goto error_return; |
07d6d2b8 | 461 | } |
a6be0538 PC |
462 | |
463 | vma += bfdsec->size; | |
464 | } | |
465 | ||
466 | /* Make sure we're at actual EOF. There's no indication in the | |
467 | WebAssembly format of how long the file is supposed to be. */ | |
468 | if (error) | |
469 | goto error_return; | |
470 | ||
471 | return TRUE; | |
472 | ||
473 | error_return: | |
a6be0538 PC |
474 | return FALSE; |
475 | } | |
476 | ||
477 | /* Put a numbered section ASECT of ABFD into the table of numbered | |
478 | sections pointed to by FSARG. */ | |
479 | ||
480 | static void | |
481 | wasm_register_section (bfd *abfd ATTRIBUTE_UNUSED, | |
07d6d2b8 | 482 | asection *asect, |
a6be0538 PC |
483 | void *fsarg) |
484 | { | |
485 | sec_ptr *numbered_sections = fsarg; | |
87993319 | 486 | int idx = wasm_section_name_to_code (asect->name); |
a6be0538 | 487 | |
87993319 | 488 | if (idx == 0) |
a6be0538 PC |
489 | return; |
490 | ||
87993319 | 491 | numbered_sections[idx] = asect; |
a6be0538 PC |
492 | } |
493 | ||
494 | struct compute_section_arg | |
495 | { | |
496 | bfd_vma pos; | |
497 | bfd_boolean failed; | |
498 | }; | |
499 | ||
500 | /* Compute the file position of ABFD's section ASECT. FSARG is a | |
501 | pointer to the current file position. | |
502 | ||
503 | We allow section names of the form .wasm.id to encode the numbered | |
504 | section with ID id, if it exists; otherwise, a custom section with | |
505 | ID "id" is produced. Arbitrary section names are for sections that | |
506 | are assumed already to contain a section header; those are appended | |
507 | to the WebAssembly module verbatim. */ | |
508 | ||
509 | static void | |
510 | wasm_compute_custom_section_file_position (bfd *abfd, | |
511 | sec_ptr asect, | |
07d6d2b8 | 512 | void *fsarg) |
a6be0538 PC |
513 | { |
514 | struct compute_section_arg *fs = fsarg; | |
87993319 | 515 | int idx; |
a6be0538 PC |
516 | |
517 | if (fs->failed) | |
518 | return; | |
519 | ||
87993319 | 520 | idx = wasm_section_name_to_code (asect->name); |
a6be0538 | 521 | |
87993319 | 522 | if (idx != 0) |
a6be0538 PC |
523 | return; |
524 | ||
525 | if (CONST_STRNEQ (asect->name, WASM_SECTION_PREFIX)) | |
526 | { | |
527 | const char *name = asect->name + strlen (WASM_SECTION_PREFIX); | |
528 | bfd_size_type payload_len = asect->size; | |
529 | bfd_size_type name_len = strlen (name); | |
530 | bfd_size_type nl = name_len; | |
531 | ||
532 | payload_len += name_len; | |
533 | ||
534 | do | |
07d6d2b8 AM |
535 | { |
536 | payload_len++; | |
537 | nl >>= 7; | |
538 | } | |
a6be0538 PC |
539 | while (nl); |
540 | ||
541 | bfd_seek (abfd, fs->pos, SEEK_SET); | |
542 | if (! wasm_write_uleb128 (abfd, 0) | |
07d6d2b8 AM |
543 | || ! wasm_write_uleb128 (abfd, payload_len) |
544 | || ! wasm_write_uleb128 (abfd, name_len) | |
545 | || bfd_bwrite (name, name_len, abfd) != name_len) | |
546 | goto error_return; | |
a6be0538 PC |
547 | fs->pos = asect->filepos = bfd_tell (abfd); |
548 | } | |
549 | else | |
550 | { | |
551 | asect->filepos = fs->pos; | |
552 | } | |
553 | ||
554 | ||
555 | fs->pos += asect->size; | |
556 | return; | |
557 | ||
558 | error_return: | |
559 | fs->failed = TRUE; | |
560 | } | |
561 | ||
562 | /* Compute the file positions for the sections of ABFD. Currently, | |
563 | this writes all numbered sections first, in order, then all custom | |
564 | sections, in section order. | |
565 | ||
566 | The spec says that the numbered sections must appear in order of | |
567 | their ids, but custom sections can appear in any position and any | |
568 | order, and more than once. FIXME: support that. */ | |
569 | ||
570 | static bfd_boolean | |
571 | wasm_compute_section_file_positions (bfd *abfd) | |
572 | { | |
573 | bfd_byte magic[SIZEOF_WASM_MAGIC] = WASM_MAGIC; | |
574 | bfd_byte vers[SIZEOF_WASM_VERSION] = WASM_VERSION; | |
575 | sec_ptr numbered_sections[WASM_NUMBERED_SECTIONS]; | |
576 | struct compute_section_arg fs; | |
577 | unsigned int i; | |
578 | ||
579 | bfd_seek (abfd, (bfd_vma) 0, SEEK_SET); | |
580 | ||
581 | if (bfd_bwrite (magic, sizeof (magic), abfd) != (sizeof magic) | |
582 | || bfd_bwrite (vers, sizeof (vers), abfd) != sizeof (vers)) | |
583 | return FALSE; | |
584 | ||
585 | for (i = 0; i < WASM_NUMBERED_SECTIONS; i++) | |
586 | numbered_sections[i] = NULL; | |
587 | ||
588 | bfd_map_over_sections (abfd, wasm_register_section, numbered_sections); | |
589 | ||
590 | fs.pos = bfd_tell (abfd); | |
591 | for (i = 0; i < WASM_NUMBERED_SECTIONS; i++) | |
592 | { | |
593 | sec_ptr sec = numbered_sections[i]; | |
594 | bfd_size_type size; | |
595 | ||
596 | if (! sec) | |
07d6d2b8 | 597 | continue; |
a6be0538 PC |
598 | size = sec->size; |
599 | if (bfd_seek (abfd, fs.pos, SEEK_SET) != 0) | |
07d6d2b8 | 600 | return FALSE; |
a6be0538 | 601 | if (! wasm_write_uleb128 (abfd, i) |
07d6d2b8 AM |
602 | || ! wasm_write_uleb128 (abfd, size)) |
603 | return FALSE; | |
a6be0538 PC |
604 | fs.pos = sec->filepos = bfd_tell (abfd); |
605 | fs.pos += size; | |
606 | } | |
607 | ||
608 | fs.failed = FALSE; | |
609 | ||
610 | bfd_map_over_sections (abfd, wasm_compute_custom_section_file_position, &fs); | |
611 | ||
612 | if (fs.failed) | |
613 | return FALSE; | |
614 | ||
615 | abfd->output_has_begun = TRUE; | |
616 | ||
617 | return TRUE; | |
618 | } | |
619 | ||
620 | static bfd_boolean | |
621 | wasm_set_section_contents (bfd *abfd, | |
07d6d2b8 AM |
622 | sec_ptr section, |
623 | const void *location, | |
624 | file_ptr offset, | |
625 | bfd_size_type count) | |
a6be0538 PC |
626 | { |
627 | if (count == 0) | |
628 | return TRUE; | |
629 | ||
630 | if (! abfd->output_has_begun | |
631 | && ! wasm_compute_section_file_positions (abfd)) | |
632 | return FALSE; | |
633 | ||
634 | if (bfd_seek (abfd, section->filepos + offset, SEEK_SET) != 0 | |
635 | || bfd_bwrite (location, count, abfd) != count) | |
636 | return FALSE; | |
637 | ||
638 | return TRUE; | |
639 | } | |
640 | ||
641 | static bfd_boolean | |
642 | wasm_write_object_contents (bfd* abfd) | |
643 | { | |
644 | bfd_byte magic[] = WASM_MAGIC; | |
645 | bfd_byte vers[] = WASM_VERSION; | |
646 | ||
647 | if (bfd_seek (abfd, 0, SEEK_SET) != 0) | |
648 | return FALSE; | |
649 | ||
650 | if (bfd_bwrite (magic, sizeof (magic), abfd) != sizeof (magic) | |
651 | || bfd_bwrite (vers, sizeof (vers), abfd) != sizeof (vers)) | |
652 | return FALSE; | |
653 | ||
654 | return TRUE; | |
655 | } | |
656 | ||
657 | static bfd_boolean | |
658 | wasm_mkobject (bfd *abfd) | |
659 | { | |
660 | tdata_type *tdata = (tdata_type *) bfd_alloc (abfd, sizeof (tdata_type)); | |
661 | ||
662 | if (! tdata) | |
663 | return FALSE; | |
664 | ||
665 | tdata->symbols = NULL; | |
666 | tdata->symcount = 0; | |
667 | ||
668 | abfd->tdata.any = tdata; | |
669 | ||
670 | return TRUE; | |
671 | } | |
672 | ||
673 | static long | |
674 | wasm_get_symtab_upper_bound (bfd *abfd) | |
675 | { | |
676 | tdata_type *tdata = abfd->tdata.any; | |
677 | ||
678 | return (tdata->symcount + 1) * (sizeof (asymbol *)); | |
679 | } | |
680 | ||
681 | static long | |
682 | wasm_canonicalize_symtab (bfd *abfd, asymbol **alocation) | |
683 | { | |
684 | tdata_type *tdata = abfd->tdata.any; | |
685 | size_t i; | |
686 | ||
687 | for (i = 0; i < tdata->symcount; i++) | |
688 | alocation[i] = &tdata->symbols[i]; | |
689 | alocation[i] = NULL; | |
690 | ||
691 | return tdata->symcount; | |
692 | } | |
693 | ||
694 | static asymbol * | |
695 | wasm_make_empty_symbol (bfd *abfd) | |
696 | { | |
986f0783 | 697 | size_t amt = sizeof (asymbol); |
a6be0538 PC |
698 | asymbol *new_symbol = (asymbol *) bfd_zalloc (abfd, amt); |
699 | ||
700 | if (! new_symbol) | |
701 | return NULL; | |
702 | new_symbol->the_bfd = abfd; | |
703 | return new_symbol; | |
704 | } | |
705 | ||
706 | static void | |
707 | wasm_print_symbol (bfd *abfd, | |
07d6d2b8 AM |
708 | void * filep, |
709 | asymbol *symbol, | |
710 | bfd_print_symbol_type how) | |
a6be0538 PC |
711 | { |
712 | FILE *file = (FILE *) filep; | |
713 | ||
714 | switch (how) | |
715 | { | |
716 | case bfd_print_symbol_name: | |
717 | fprintf (file, "%s", symbol->name); | |
718 | break; | |
719 | ||
720 | default: | |
721 | bfd_print_symbol_vandf (abfd, filep, symbol); | |
722 | fprintf (file, " %-5s %s", symbol->section->name, symbol->name); | |
723 | } | |
724 | } | |
725 | ||
726 | static void | |
727 | wasm_get_symbol_info (bfd *abfd ATTRIBUTE_UNUSED, | |
07d6d2b8 AM |
728 | asymbol *symbol, |
729 | symbol_info *ret) | |
a6be0538 PC |
730 | { |
731 | bfd_symbol_info (symbol, ret); | |
732 | } | |
733 | ||
734 | /* Check whether ABFD is a WebAssembly module; if so, scan it. */ | |
735 | ||
736 | static const bfd_target * | |
737 | wasm_object_p (bfd *abfd) | |
738 | { | |
739 | bfd_boolean error; | |
0c0adcc5 | 740 | asection *s; |
a6be0538 PC |
741 | |
742 | if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0) | |
743 | return NULL; | |
744 | ||
0c0adcc5 | 745 | if (!wasm_read_header (abfd, &error)) |
a6be0538 PC |
746 | { |
747 | bfd_set_error (bfd_error_wrong_format); | |
748 | return NULL; | |
749 | } | |
750 | ||
0c0adcc5 | 751 | if (!wasm_mkobject (abfd)) |
a6be0538 PC |
752 | return NULL; |
753 | ||
0c0adcc5 AM |
754 | if (!wasm_scan (abfd) |
755 | || !bfd_default_set_arch_mach (abfd, bfd_arch_wasm32, 0)) | |
756 | { | |
757 | bfd_release (abfd, abfd->tdata.any); | |
758 | abfd->tdata.any = NULL; | |
759 | return NULL; | |
760 | } | |
a6be0538 | 761 | |
0c0adcc5 AM |
762 | s = bfd_get_section_by_name (abfd, WASM_NAME_SECTION); |
763 | if (s != NULL && wasm_scan_name_function_section (abfd, s)) | |
a6be0538 PC |
764 | abfd->flags |= HAS_SYMS; |
765 | ||
766 | return abfd->xvec; | |
767 | } | |
768 | ||
769 | /* BFD_JUMP_TABLE_WRITE */ | |
07d6d2b8 | 770 | #define wasm_set_arch_mach _bfd_generic_set_arch_mach |
a6be0538 PC |
771 | |
772 | /* BFD_JUMP_TABLE_SYMBOLS */ | |
07d6d2b8 AM |
773 | #define wasm_get_symbol_version_string _bfd_nosymbols_get_symbol_version_string |
774 | #define wasm_bfd_is_local_label_name bfd_generic_is_local_label_name | |
d00dd7dc | 775 | #define wasm_bfd_is_target_special_symbol _bfd_bool_bfd_asymbol_false |
07d6d2b8 AM |
776 | #define wasm_get_lineno _bfd_nosymbols_get_lineno |
777 | #define wasm_find_nearest_line _bfd_nosymbols_find_nearest_line | |
778 | #define wasm_find_line _bfd_nosymbols_find_line | |
779 | #define wasm_find_inliner_info _bfd_nosymbols_find_inliner_info | |
780 | #define wasm_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol | |
781 | #define wasm_read_minisymbols _bfd_generic_read_minisymbols | |
782 | #define wasm_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol | |
a6be0538 PC |
783 | |
784 | const bfd_target wasm_vec = | |
785 | { | |
07d6d2b8 | 786 | "wasm", /* Name. */ |
a6be0538 PC |
787 | bfd_target_unknown_flavour, |
788 | BFD_ENDIAN_LITTLE, | |
789 | BFD_ENDIAN_LITTLE, | |
790 | (HAS_SYMS | WP_TEXT), /* Object flags. */ | |
791 | (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS), /* Section flags. */ | |
07d6d2b8 AM |
792 | 0, /* Leading underscore. */ |
793 | ' ', /* AR_pad_char. */ | |
794 | 255, /* AR_max_namelen. */ | |
a6be0538 PC |
795 | 0, /* Match priority. */ |
796 | /* Routines to byte-swap various sized integers from the data sections. */ | |
797 | bfd_getl64, bfd_getl_signed_64, bfd_putl64, | |
798 | bfd_getl32, bfd_getl_signed_32, bfd_putl32, | |
799 | bfd_getl16, bfd_getl_signed_16, bfd_putl16, | |
800 | ||
801 | /* Routines to byte-swap various sized integers from the file headers. */ | |
802 | bfd_getl64, bfd_getl_signed_64, bfd_putl64, | |
803 | bfd_getl32, bfd_getl_signed_32, bfd_putl32, | |
804 | bfd_getl16, bfd_getl_signed_16, bfd_putl16, | |
805 | ||
806 | { | |
807 | _bfd_dummy_target, | |
808 | wasm_object_p, /* bfd_check_format. */ | |
809 | _bfd_dummy_target, | |
810 | _bfd_dummy_target, | |
811 | }, | |
812 | { | |
d00dd7dc | 813 | _bfd_bool_bfd_false_error, |
a6be0538 PC |
814 | wasm_mkobject, |
815 | _bfd_generic_mkarchive, | |
d00dd7dc | 816 | _bfd_bool_bfd_false_error, |
a6be0538 PC |
817 | }, |
818 | { /* bfd_write_contents. */ | |
d00dd7dc | 819 | _bfd_bool_bfd_false_error, |
a6be0538 PC |
820 | wasm_write_object_contents, |
821 | _bfd_write_archive_contents, | |
d00dd7dc | 822 | _bfd_bool_bfd_false_error, |
a6be0538 PC |
823 | }, |
824 | ||
825 | BFD_JUMP_TABLE_GENERIC (_bfd_generic), | |
826 | BFD_JUMP_TABLE_COPY (_bfd_generic), | |
827 | BFD_JUMP_TABLE_CORE (_bfd_nocore), | |
828 | BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive), | |
829 | BFD_JUMP_TABLE_SYMBOLS (wasm), | |
830 | BFD_JUMP_TABLE_RELOCS (_bfd_norelocs), | |
831 | BFD_JUMP_TABLE_WRITE (wasm), | |
832 | BFD_JUMP_TABLE_LINK (_bfd_nolink), | |
833 | BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic), | |
834 | ||
835 | NULL, | |
836 | ||
837 | NULL, | |
838 | }; |