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62ecb94c | 1 | /* Opcode printing code for the WebAssembly target |
b3adc24a | 2 | Copyright (C) 2017-2020 Free Software Foundation, Inc. |
62ecb94c PC |
3 | |
4 | This file is part of libopcodes. | |
5 | ||
6 | This library is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 3 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | It is distributed in the hope that it will be useful, but WITHOUT | |
12 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
13 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public | |
14 | License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, | |
19 | MA 02110-1301, USA. */ | |
20 | ||
21 | #include "sysdep.h" | |
88c1242d | 22 | #include "disassemble.h" |
62ecb94c PC |
23 | #include "opintl.h" |
24 | #include "safe-ctype.h" | |
25 | #include "floatformat.h" | |
62ecb94c PC |
26 | #include "libiberty.h" |
27 | #include "elf-bfd.h" | |
28 | #include "elf/internal.h" | |
29 | #include "elf/wasm32.h" | |
2d5d5a8f | 30 | #include "bfd_stdint.h" |
62ecb94c PC |
31 | |
32 | /* Type names for blocks and signatures. */ | |
33 | #define BLOCK_TYPE_NONE 0x40 | |
34 | #define BLOCK_TYPE_I32 0x7f | |
35 | #define BLOCK_TYPE_I64 0x7e | |
36 | #define BLOCK_TYPE_F32 0x7d | |
37 | #define BLOCK_TYPE_F64 0x7c | |
38 | ||
39 | enum wasm_class | |
40 | { | |
41 | wasm_typed, | |
42 | wasm_special, | |
43 | wasm_break, | |
44 | wasm_break_if, | |
45 | wasm_break_table, | |
46 | wasm_return, | |
47 | wasm_call, | |
48 | wasm_call_import, | |
49 | wasm_call_indirect, | |
50 | wasm_get_local, | |
51 | wasm_set_local, | |
52 | wasm_tee_local, | |
53 | wasm_drop, | |
54 | wasm_constant_i32, | |
55 | wasm_constant_i64, | |
56 | wasm_constant_f32, | |
57 | wasm_constant_f64, | |
58 | wasm_unary, | |
59 | wasm_binary, | |
60 | wasm_conv, | |
61 | wasm_load, | |
62 | wasm_store, | |
63 | wasm_select, | |
64 | wasm_relational, | |
65 | wasm_eqz, | |
66 | wasm_current_memory, | |
67 | wasm_grow_memory, | |
68 | wasm_signature | |
69 | }; | |
70 | ||
71 | struct wasm32_private_data | |
72 | { | |
73 | bfd_boolean print_registers; | |
74 | bfd_boolean print_well_known_globals; | |
75 | ||
76 | /* Limit valid symbols to those with a given prefix. */ | |
77 | const char *section_prefix; | |
78 | }; | |
79 | ||
80 | typedef struct | |
81 | { | |
82 | const char *name; | |
83 | const char *description; | |
84 | } wasm32_options_t; | |
85 | ||
86 | static const wasm32_options_t options[] = | |
87 | { | |
88 | { "registers", N_("Disassemble \"register\" names") }, | |
89 | { "globals", N_("Name well-known globals") }, | |
90 | }; | |
91 | ||
92 | #define WASM_OPCODE(opcode, name, intype, outtype, clas, signedness) \ | |
93 | { name, wasm_ ## clas, opcode }, | |
94 | ||
95 | struct wasm32_opcode_s | |
96 | { | |
97 | const char *name; | |
98 | enum wasm_class clas; | |
99 | unsigned char opcode; | |
100 | } wasm32_opcodes[] = | |
101 | { | |
102 | #include "opcode/wasm.h" | |
103 | { NULL, 0, 0 } | |
104 | }; | |
105 | ||
106 | /* Parse the disassembler options in OPTS and initialize INFO. */ | |
107 | ||
108 | static void | |
109 | parse_wasm32_disassembler_options (struct disassemble_info *info, | |
110 | const char *opts) | |
111 | { | |
112 | struct wasm32_private_data *private = info->private_data; | |
113 | ||
114 | while (opts != NULL) | |
115 | { | |
116 | if (CONST_STRNEQ (opts, "registers")) | |
117 | private->print_registers = TRUE; | |
118 | else if (CONST_STRNEQ (opts, "globals")) | |
119 | private->print_well_known_globals = TRUE; | |
120 | ||
121 | opts = strchr (opts, ','); | |
122 | if (opts) | |
123 | opts++; | |
124 | } | |
125 | } | |
126 | ||
127 | /* Check whether SYM is valid. Special-case absolute symbols, which | |
128 | are unhelpful to print, and arguments to a "call" insn, which we | |
129 | want to be in a section matching a given prefix. */ | |
130 | ||
131 | static bfd_boolean | |
132 | wasm32_symbol_is_valid (asymbol *sym, | |
133 | struct disassemble_info *info) | |
134 | { | |
135 | struct wasm32_private_data *private_data = info->private_data; | |
136 | ||
137 | if (sym == NULL) | |
138 | return FALSE; | |
139 | ||
140 | if (strcmp(sym->section->name, "*ABS*") == 0) | |
141 | return FALSE; | |
142 | ||
143 | if (private_data && private_data->section_prefix != NULL | |
144 | && strncmp (sym->section->name, private_data->section_prefix, | |
145 | strlen (private_data->section_prefix))) | |
146 | return FALSE; | |
147 | ||
148 | return TRUE; | |
149 | } | |
150 | ||
151 | /* Initialize the disassembler structures for INFO. */ | |
152 | ||
153 | void | |
154 | disassemble_init_wasm32 (struct disassemble_info *info) | |
155 | { | |
156 | if (info->private_data == NULL) | |
157 | { | |
158 | static struct wasm32_private_data private; | |
159 | ||
160 | private.print_registers = FALSE; | |
161 | private.print_well_known_globals = FALSE; | |
162 | private.section_prefix = NULL; | |
163 | ||
164 | info->private_data = &private; | |
165 | } | |
166 | ||
167 | if (info->disassembler_options) | |
168 | { | |
169 | parse_wasm32_disassembler_options (info, info->disassembler_options); | |
170 | ||
171 | info->disassembler_options = NULL; | |
172 | } | |
173 | ||
174 | info->symbol_is_valid = wasm32_symbol_is_valid; | |
175 | } | |
176 | ||
177 | /* Read an LEB128-encoded integer from INFO at address PC, reading one | |
178 | byte at a time. Set ERROR_RETURN if no complete integer could be | |
179 | read, LENGTH_RETURN to the number oof bytes read (including bytes | |
180 | in incomplete numbers). SIGN means interpret the number as | |
181 | SLEB128. Unfortunately, this is a duplicate of wasm-module.c's | |
182 | wasm_read_leb128 (). */ | |
183 | ||
184 | static uint64_t | |
185 | wasm_read_leb128 (bfd_vma pc, | |
186 | struct disassemble_info * info, | |
187 | bfd_boolean * error_return, | |
188 | unsigned int * length_return, | |
189 | bfd_boolean sign) | |
190 | { | |
191 | uint64_t result = 0; | |
192 | unsigned int num_read = 0; | |
193 | unsigned int shift = 0; | |
194 | unsigned char byte = 0; | |
27c1c427 | 195 | int status = 1; |
62ecb94c PC |
196 | |
197 | while (info->read_memory_func (pc + num_read, &byte, 1, info) == 0) | |
198 | { | |
199 | num_read++; | |
200 | ||
27c1c427 AM |
201 | if (shift < sizeof (result) * 8) |
202 | { | |
203 | result |= ((uint64_t) (byte & 0x7f)) << shift; | |
204 | if ((result >> shift) != (byte & 0x7f)) | |
205 | /* Overflow. */ | |
206 | status |= 2; | |
207 | shift += 7; | |
208 | } | |
209 | else if ((byte & 0x7f) != 0) | |
210 | status |= 2; | |
62ecb94c | 211 | |
62ecb94c | 212 | if ((byte & 0x80) == 0) |
27c1c427 AM |
213 | { |
214 | status &= ~1; | |
215 | if (sign && (shift < 8 * sizeof (result)) && (byte & 0x40)) | |
216 | result |= -((uint64_t) 1 << shift); | |
217 | break; | |
218 | } | |
62ecb94c PC |
219 | } |
220 | ||
221 | if (length_return != NULL) | |
222 | *length_return = num_read; | |
223 | if (error_return != NULL) | |
27c1c427 | 224 | *error_return = status != 0; |
62ecb94c PC |
225 | |
226 | return result; | |
227 | } | |
228 | ||
229 | /* Read a 32-bit IEEE float from PC using INFO, convert it to a host | |
230 | double, and store it at VALUE. */ | |
231 | ||
232 | static int | |
233 | read_f32 (double *value, bfd_vma pc, struct disassemble_info *info) | |
234 | { | |
235 | bfd_byte buf[4]; | |
236 | ||
237 | if (info->read_memory_func (pc, buf, sizeof (buf), info)) | |
238 | return -1; | |
239 | ||
240 | floatformat_to_double (&floatformat_ieee_single_little, buf, | |
241 | value); | |
242 | ||
243 | return sizeof (buf); | |
244 | } | |
245 | ||
246 | /* Read a 64-bit IEEE float from PC using INFO, convert it to a host | |
247 | double, and store it at VALUE. */ | |
248 | ||
249 | static int | |
250 | read_f64 (double *value, bfd_vma pc, struct disassemble_info *info) | |
251 | { | |
252 | bfd_byte buf[8]; | |
253 | ||
254 | if (info->read_memory_func (pc, buf, sizeof (buf), info)) | |
255 | return -1; | |
256 | ||
257 | floatformat_to_double (&floatformat_ieee_double_little, buf, | |
258 | value); | |
259 | ||
260 | return sizeof (buf); | |
261 | } | |
262 | ||
263 | /* Main disassembly routine. Disassemble insn at PC using INFO. */ | |
264 | ||
265 | int | |
266 | print_insn_wasm32 (bfd_vma pc, struct disassemble_info *info) | |
267 | { | |
268 | unsigned char opcode; | |
269 | struct wasm32_opcode_s *op; | |
270 | bfd_byte buffer[16]; | |
271 | void *stream = info->stream; | |
272 | fprintf_ftype prin = info->fprintf_func; | |
273 | struct wasm32_private_data *private_data = info->private_data; | |
febda64f AM |
274 | uint64_t val; |
275 | int len; | |
276 | unsigned int bytes_read; | |
277 | bfd_boolean error; | |
62ecb94c PC |
278 | |
279 | if (info->read_memory_func (pc, buffer, 1, info)) | |
280 | return -1; | |
281 | ||
282 | opcode = buffer[0]; | |
283 | ||
284 | for (op = wasm32_opcodes; op->name; op++) | |
285 | if (op->opcode == opcode) | |
286 | break; | |
287 | ||
288 | if (!op->name) | |
289 | { | |
290 | prin (stream, "\t.byte 0x%02x\n", buffer[0]); | |
291 | return 1; | |
292 | } | |
febda64f AM |
293 | |
294 | len = 1; | |
295 | ||
296 | prin (stream, "\t"); | |
297 | prin (stream, "%s", op->name); | |
298 | ||
299 | if (op->clas == wasm_typed) | |
62ecb94c | 300 | { |
febda64f AM |
301 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, FALSE); |
302 | if (error) | |
303 | return -1; | |
304 | len += bytes_read; | |
305 | switch (val) | |
306 | { | |
307 | case BLOCK_TYPE_NONE: | |
308 | prin (stream, "[]"); | |
309 | break; | |
310 | case BLOCK_TYPE_I32: | |
311 | prin (stream, "[i]"); | |
312 | break; | |
313 | case BLOCK_TYPE_I64: | |
314 | prin (stream, "[l]"); | |
315 | break; | |
316 | case BLOCK_TYPE_F32: | |
317 | prin (stream, "[f]"); | |
318 | break; | |
319 | case BLOCK_TYPE_F64: | |
320 | prin (stream, "[d]"); | |
321 | break; | |
322 | default: | |
323 | return -1; | |
324 | } | |
325 | } | |
326 | ||
327 | switch (op->clas) | |
328 | { | |
329 | case wasm_special: | |
330 | case wasm_eqz: | |
331 | case wasm_binary: | |
332 | case wasm_unary: | |
333 | case wasm_conv: | |
334 | case wasm_relational: | |
335 | case wasm_drop: | |
336 | case wasm_signature: | |
337 | case wasm_call_import: | |
338 | case wasm_typed: | |
339 | case wasm_select: | |
340 | break; | |
341 | ||
342 | case wasm_break_table: | |
343 | { | |
344 | uint32_t target_count, i; | |
345 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, | |
346 | FALSE); | |
347 | target_count = val; | |
348 | if (error || target_count != val || target_count == (uint32_t) -1) | |
349 | return -1; | |
350 | len += bytes_read; | |
351 | prin (stream, " %u", target_count); | |
352 | for (i = 0; i < target_count + 1; i++) | |
353 | { | |
354 | uint32_t target; | |
355 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, | |
356 | FALSE); | |
357 | target = val; | |
358 | if (error || target != val) | |
359 | return -1; | |
360 | len += bytes_read; | |
361 | prin (stream, " %u", target); | |
362 | } | |
363 | } | |
364 | break; | |
365 | ||
366 | case wasm_break: | |
367 | case wasm_break_if: | |
368 | { | |
369 | uint32_t depth; | |
370 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, | |
371 | FALSE); | |
372 | depth = val; | |
373 | if (error || depth != val) | |
374 | return -1; | |
375 | len += bytes_read; | |
376 | prin (stream, " %u", depth); | |
377 | } | |
378 | break; | |
379 | ||
380 | case wasm_return: | |
381 | break; | |
382 | ||
383 | case wasm_constant_i32: | |
384 | case wasm_constant_i64: | |
385 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, TRUE); | |
386 | if (error) | |
387 | return -1; | |
388 | len += bytes_read; | |
389 | prin (stream, " %" PRId64, val); | |
390 | break; | |
391 | ||
392 | case wasm_constant_f32: | |
393 | { | |
394 | double fconstant; | |
395 | int ret; | |
396 | /* This appears to be the best we can do, even though we're | |
397 | using host doubles for WebAssembly floats. */ | |
398 | ret = read_f32 (&fconstant, pc + len, info); | |
399 | if (ret < 0) | |
400 | return -1; | |
401 | len += ret; | |
402 | prin (stream, " %.9g", fconstant); | |
403 | } | |
404 | break; | |
405 | ||
406 | case wasm_constant_f64: | |
407 | { | |
408 | double fconstant; | |
409 | int ret; | |
410 | ret = read_f64 (&fconstant, pc + len, info); | |
411 | if (ret < 0) | |
412 | return -1; | |
413 | len += ret; | |
414 | prin (stream, " %.17g", fconstant); | |
415 | } | |
416 | break; | |
417 | ||
418 | case wasm_call: | |
419 | { | |
420 | uint32_t function_index; | |
421 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, | |
422 | FALSE); | |
423 | function_index = val; | |
424 | if (error || function_index != val) | |
425 | return -1; | |
426 | len += bytes_read; | |
427 | prin (stream, " "); | |
428 | private_data->section_prefix = ".space.function_index"; | |
429 | (*info->print_address_func) ((bfd_vma) function_index, info); | |
430 | private_data->section_prefix = NULL; | |
431 | } | |
432 | break; | |
433 | ||
434 | case wasm_call_indirect: | |
435 | { | |
436 | uint32_t type_index, xtra_index; | |
437 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, | |
438 | FALSE); | |
439 | type_index = val; | |
440 | if (error || type_index != val) | |
441 | return -1; | |
442 | len += bytes_read; | |
443 | prin (stream, " %u", type_index); | |
444 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, | |
445 | FALSE); | |
446 | xtra_index = val; | |
447 | if (error || xtra_index != val) | |
448 | return -1; | |
449 | len += bytes_read; | |
450 | prin (stream, " %u", xtra_index); | |
451 | } | |
452 | break; | |
453 | ||
454 | case wasm_get_local: | |
455 | case wasm_set_local: | |
456 | case wasm_tee_local: | |
457 | { | |
458 | uint32_t local_index; | |
459 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, | |
460 | FALSE); | |
461 | local_index = val; | |
462 | if (error || local_index != val) | |
463 | return -1; | |
464 | len += bytes_read; | |
465 | prin (stream, " %u", local_index); | |
466 | if (strcmp (op->name + 4, "local") == 0) | |
467 | { | |
468 | static const char *locals[] = | |
469 | { | |
470 | "$dpc", "$sp1", "$r0", "$r1", "$rpc", "$pc0", | |
471 | "$rp", "$fp", "$sp", | |
472 | "$r2", "$r3", "$r4", "$r5", "$r6", "$r7", | |
473 | "$i0", "$i1", "$i2", "$i3", "$i4", "$i5", "$i6", "$i7", | |
474 | "$f0", "$f1", "$f2", "$f3", "$f4", "$f5", "$f6", "$f7", | |
475 | }; | |
476 | if (private_data->print_registers | |
477 | && local_index < ARRAY_SIZE (locals)) | |
478 | prin (stream, " <%s>", locals[local_index]); | |
479 | } | |
480 | else | |
481 | { | |
482 | static const char *globals[] = | |
483 | { | |
484 | "$got", "$plt", "$gpo" | |
485 | }; | |
486 | if (private_data->print_well_known_globals | |
487 | && local_index < ARRAY_SIZE (globals)) | |
488 | prin (stream, " <%s>", globals[local_index]); | |
489 | } | |
490 | } | |
491 | break; | |
492 | ||
493 | case wasm_grow_memory: | |
494 | case wasm_current_memory: | |
495 | { | |
496 | uint32_t reserved_size; | |
497 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, | |
498 | FALSE); | |
499 | reserved_size = val; | |
500 | if (error || reserved_size != val) | |
501 | return -1; | |
502 | len += bytes_read; | |
503 | prin (stream, " %u", reserved_size); | |
504 | } | |
505 | break; | |
506 | ||
507 | case wasm_load: | |
508 | case wasm_store: | |
509 | { | |
510 | uint32_t flags, offset; | |
511 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, | |
512 | FALSE); | |
513 | flags = val; | |
514 | if (error || flags != val) | |
515 | return -1; | |
516 | len += bytes_read; | |
517 | val = wasm_read_leb128 (pc + len, info, &error, &bytes_read, | |
518 | FALSE); | |
519 | offset = val; | |
520 | if (error || offset != val) | |
521 | return -1; | |
522 | len += bytes_read; | |
523 | prin (stream, " a=%u %u", flags, offset); | |
524 | } | |
525 | break; | |
62ecb94c PC |
526 | } |
527 | return len; | |
528 | } | |
529 | ||
530 | /* Print valid disassembler options to STREAM. */ | |
531 | ||
532 | void | |
533 | print_wasm32_disassembler_options (FILE *stream) | |
534 | { | |
535 | unsigned int i, max_len = 0; | |
536 | ||
537 | fprintf (stream, _("\ | |
538 | The following WebAssembly-specific disassembler options are supported for use\n\ | |
539 | with the -M switch:\n")); | |
540 | ||
541 | for (i = 0; i < ARRAY_SIZE (options); i++) | |
542 | { | |
543 | unsigned int len = strlen (options[i].name); | |
544 | ||
545 | if (max_len < len) | |
546 | max_len = len; | |
547 | } | |
548 | ||
549 | for (i = 0, max_len++; i < ARRAY_SIZE (options); i++) | |
550 | fprintf (stream, " %s%*c %s\n", | |
551 | options[i].name, | |
552 | (int)(max_len - strlen (options[i].name)), ' ', | |
553 | _(options[i].description)); | |
554 | } |