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62ecb94c PC |
1 | /* Opcode printing code for the WebAssembly target |
2 | Copyright (C) 2017 Free Software Foundation, Inc. | |
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" | |
22 | #include "dis-asm.h" | |
23 | #include "opintl.h" | |
24 | #include "safe-ctype.h" | |
25 | #include "floatformat.h" | |
26 | #include <float.h> | |
27 | #include "libiberty.h" | |
28 | #include "elf-bfd.h" | |
29 | #include "elf/internal.h" | |
30 | #include "elf/wasm32.h" | |
31 | #include <stdint.h> | |
32 | ||
33 | /* Type names for blocks and signatures. */ | |
34 | #define BLOCK_TYPE_NONE 0x40 | |
35 | #define BLOCK_TYPE_I32 0x7f | |
36 | #define BLOCK_TYPE_I64 0x7e | |
37 | #define BLOCK_TYPE_F32 0x7d | |
38 | #define BLOCK_TYPE_F64 0x7c | |
39 | ||
40 | enum wasm_class | |
41 | { | |
42 | wasm_typed, | |
43 | wasm_special, | |
44 | wasm_break, | |
45 | wasm_break_if, | |
46 | wasm_break_table, | |
47 | wasm_return, | |
48 | wasm_call, | |
49 | wasm_call_import, | |
50 | wasm_call_indirect, | |
51 | wasm_get_local, | |
52 | wasm_set_local, | |
53 | wasm_tee_local, | |
54 | wasm_drop, | |
55 | wasm_constant_i32, | |
56 | wasm_constant_i64, | |
57 | wasm_constant_f32, | |
58 | wasm_constant_f64, | |
59 | wasm_unary, | |
60 | wasm_binary, | |
61 | wasm_conv, | |
62 | wasm_load, | |
63 | wasm_store, | |
64 | wasm_select, | |
65 | wasm_relational, | |
66 | wasm_eqz, | |
67 | wasm_current_memory, | |
68 | wasm_grow_memory, | |
69 | wasm_signature | |
70 | }; | |
71 | ||
72 | struct wasm32_private_data | |
73 | { | |
74 | bfd_boolean print_registers; | |
75 | bfd_boolean print_well_known_globals; | |
76 | ||
77 | /* Limit valid symbols to those with a given prefix. */ | |
78 | const char *section_prefix; | |
79 | }; | |
80 | ||
81 | typedef struct | |
82 | { | |
83 | const char *name; | |
84 | const char *description; | |
85 | } wasm32_options_t; | |
86 | ||
87 | static const wasm32_options_t options[] = | |
88 | { | |
89 | { "registers", N_("Disassemble \"register\" names") }, | |
90 | { "globals", N_("Name well-known globals") }, | |
91 | }; | |
92 | ||
93 | #define WASM_OPCODE(opcode, name, intype, outtype, clas, signedness) \ | |
94 | { name, wasm_ ## clas, opcode }, | |
95 | ||
96 | struct wasm32_opcode_s | |
97 | { | |
98 | const char *name; | |
99 | enum wasm_class clas; | |
100 | unsigned char opcode; | |
101 | } wasm32_opcodes[] = | |
102 | { | |
103 | #include "opcode/wasm.h" | |
104 | { NULL, 0, 0 } | |
105 | }; | |
106 | ||
107 | /* Parse the disassembler options in OPTS and initialize INFO. */ | |
108 | ||
109 | static void | |
110 | parse_wasm32_disassembler_options (struct disassemble_info *info, | |
111 | const char *opts) | |
112 | { | |
113 | struct wasm32_private_data *private = info->private_data; | |
114 | ||
115 | while (opts != NULL) | |
116 | { | |
117 | if (CONST_STRNEQ (opts, "registers")) | |
118 | private->print_registers = TRUE; | |
119 | else if (CONST_STRNEQ (opts, "globals")) | |
120 | private->print_well_known_globals = TRUE; | |
121 | ||
122 | opts = strchr (opts, ','); | |
123 | if (opts) | |
124 | opts++; | |
125 | } | |
126 | } | |
127 | ||
128 | /* Check whether SYM is valid. Special-case absolute symbols, which | |
129 | are unhelpful to print, and arguments to a "call" insn, which we | |
130 | want to be in a section matching a given prefix. */ | |
131 | ||
132 | static bfd_boolean | |
133 | wasm32_symbol_is_valid (asymbol *sym, | |
134 | struct disassemble_info *info) | |
135 | { | |
136 | struct wasm32_private_data *private_data = info->private_data; | |
137 | ||
138 | if (sym == NULL) | |
139 | return FALSE; | |
140 | ||
141 | if (strcmp(sym->section->name, "*ABS*") == 0) | |
142 | return FALSE; | |
143 | ||
144 | if (private_data && private_data->section_prefix != NULL | |
145 | && strncmp (sym->section->name, private_data->section_prefix, | |
146 | strlen (private_data->section_prefix))) | |
147 | return FALSE; | |
148 | ||
149 | return TRUE; | |
150 | } | |
151 | ||
152 | /* Initialize the disassembler structures for INFO. */ | |
153 | ||
154 | void | |
155 | disassemble_init_wasm32 (struct disassemble_info *info) | |
156 | { | |
157 | if (info->private_data == NULL) | |
158 | { | |
159 | static struct wasm32_private_data private; | |
160 | ||
161 | private.print_registers = FALSE; | |
162 | private.print_well_known_globals = FALSE; | |
163 | private.section_prefix = NULL; | |
164 | ||
165 | info->private_data = &private; | |
166 | } | |
167 | ||
168 | if (info->disassembler_options) | |
169 | { | |
170 | parse_wasm32_disassembler_options (info, info->disassembler_options); | |
171 | ||
172 | info->disassembler_options = NULL; | |
173 | } | |
174 | ||
175 | info->symbol_is_valid = wasm32_symbol_is_valid; | |
176 | } | |
177 | ||
178 | /* Read an LEB128-encoded integer from INFO at address PC, reading one | |
179 | byte at a time. Set ERROR_RETURN if no complete integer could be | |
180 | read, LENGTH_RETURN to the number oof bytes read (including bytes | |
181 | in incomplete numbers). SIGN means interpret the number as | |
182 | SLEB128. Unfortunately, this is a duplicate of wasm-module.c's | |
183 | wasm_read_leb128 (). */ | |
184 | ||
185 | static uint64_t | |
186 | wasm_read_leb128 (bfd_vma pc, | |
187 | struct disassemble_info * info, | |
188 | bfd_boolean * error_return, | |
189 | unsigned int * length_return, | |
190 | bfd_boolean sign) | |
191 | { | |
192 | uint64_t result = 0; | |
193 | unsigned int num_read = 0; | |
194 | unsigned int shift = 0; | |
195 | unsigned char byte = 0; | |
196 | bfd_boolean success = FALSE; | |
197 | ||
198 | while (info->read_memory_func (pc + num_read, &byte, 1, info) == 0) | |
199 | { | |
200 | num_read++; | |
201 | ||
202 | result |= ((bfd_vma) (byte & 0x7f)) << shift; | |
203 | ||
204 | shift += 7; | |
205 | if ((byte & 0x80) == 0) | |
206 | { | |
207 | success = TRUE; | |
208 | break; | |
209 | } | |
210 | } | |
211 | ||
212 | if (length_return != NULL) | |
213 | *length_return = num_read; | |
214 | if (error_return != NULL) | |
215 | *error_return = ! success; | |
216 | ||
217 | if (sign && (shift < 8 * sizeof (result)) && (byte & 0x40)) | |
218 | result |= -((uint64_t) 1 << shift); | |
219 | ||
220 | return result; | |
221 | } | |
222 | ||
223 | /* Read a 32-bit IEEE float from PC using INFO, convert it to a host | |
224 | double, and store it at VALUE. */ | |
225 | ||
226 | static int | |
227 | read_f32 (double *value, bfd_vma pc, struct disassemble_info *info) | |
228 | { | |
229 | bfd_byte buf[4]; | |
230 | ||
231 | if (info->read_memory_func (pc, buf, sizeof (buf), info)) | |
232 | return -1; | |
233 | ||
234 | floatformat_to_double (&floatformat_ieee_single_little, buf, | |
235 | value); | |
236 | ||
237 | return sizeof (buf); | |
238 | } | |
239 | ||
240 | /* Read a 64-bit IEEE float from PC using INFO, convert it to a host | |
241 | double, and store it at VALUE. */ | |
242 | ||
243 | static int | |
244 | read_f64 (double *value, bfd_vma pc, struct disassemble_info *info) | |
245 | { | |
246 | bfd_byte buf[8]; | |
247 | ||
248 | if (info->read_memory_func (pc, buf, sizeof (buf), info)) | |
249 | return -1; | |
250 | ||
251 | floatformat_to_double (&floatformat_ieee_double_little, buf, | |
252 | value); | |
253 | ||
254 | return sizeof (buf); | |
255 | } | |
256 | ||
257 | /* Main disassembly routine. Disassemble insn at PC using INFO. */ | |
258 | ||
259 | int | |
260 | print_insn_wasm32 (bfd_vma pc, struct disassemble_info *info) | |
261 | { | |
262 | unsigned char opcode; | |
263 | struct wasm32_opcode_s *op; | |
264 | bfd_byte buffer[16]; | |
265 | void *stream = info->stream; | |
266 | fprintf_ftype prin = info->fprintf_func; | |
267 | struct wasm32_private_data *private_data = info->private_data; | |
268 | long long constant = 0; | |
269 | double fconstant = 0.0; | |
270 | long flags = 0; | |
271 | long offset = 0; | |
272 | long depth = 0; | |
273 | long index = 0; | |
274 | long target_count = 0; | |
275 | long block_type = 0; | |
276 | int len = 1; | |
277 | int ret = 0; | |
278 | unsigned int bytes_read = 0; | |
279 | int i; | |
280 | const char *locals[] = | |
281 | { | |
282 | "$dpc", "$sp1", "$r0", "$r1", "$rpc", "$pc0", | |
283 | "$rp", "$fp", "$sp", | |
284 | "$r2", "$r3", "$r4", "$r5", "$r6", "$r7", | |
285 | "$i0", "$i1", "$i2", "$i3", "$i4", "$i5", "$i6", "$i7", | |
286 | "$f0", "$f1", "$f2", "$f3", "$f4", "$f5", "$f6", "$f7", | |
287 | }; | |
288 | int nlocals = ARRAY_SIZE (locals); | |
289 | const char *globals[] = | |
290 | { | |
291 | "$got", "$plt", "$gpo" | |
292 | }; | |
293 | int nglobals = ARRAY_SIZE (globals); | |
294 | bfd_boolean error = FALSE; | |
295 | ||
296 | if (info->read_memory_func (pc, buffer, 1, info)) | |
297 | return -1; | |
298 | ||
299 | opcode = buffer[0]; | |
300 | ||
301 | for (op = wasm32_opcodes; op->name; op++) | |
302 | if (op->opcode == opcode) | |
303 | break; | |
304 | ||
305 | if (!op->name) | |
306 | { | |
307 | prin (stream, "\t.byte 0x%02x\n", buffer[0]); | |
308 | return 1; | |
309 | } | |
310 | else | |
311 | { | |
312 | len = 1; | |
313 | ||
314 | prin (stream, "\t"); | |
315 | prin (stream, "%s", op->name); | |
316 | ||
317 | if (op->clas == wasm_typed) | |
318 | { | |
319 | block_type = wasm_read_leb128 | |
320 | (pc + len, info, &error, &bytes_read, FALSE); | |
321 | if (error) | |
322 | return -1; | |
323 | len += bytes_read; | |
324 | switch (block_type) | |
325 | { | |
326 | case BLOCK_TYPE_NONE: | |
327 | prin (stream, "[]"); | |
328 | break; | |
329 | case BLOCK_TYPE_I32: | |
330 | prin (stream, "[i]"); | |
331 | break; | |
332 | case BLOCK_TYPE_I64: | |
333 | prin (stream, "[l]"); | |
334 | break; | |
335 | case BLOCK_TYPE_F32: | |
336 | prin (stream, "[f]"); | |
337 | break; | |
338 | case BLOCK_TYPE_F64: | |
339 | prin (stream, "[d]"); | |
340 | break; | |
341 | } | |
342 | } | |
343 | ||
344 | switch (op->clas) | |
345 | { | |
346 | case wasm_special: | |
347 | case wasm_eqz: | |
348 | case wasm_binary: | |
349 | case wasm_unary: | |
350 | case wasm_conv: | |
351 | case wasm_relational: | |
352 | case wasm_drop: | |
353 | case wasm_signature: | |
354 | case wasm_call_import: | |
355 | case wasm_typed: | |
356 | case wasm_select: | |
357 | break; | |
358 | ||
359 | case wasm_break_table: | |
360 | target_count = wasm_read_leb128 | |
361 | (pc + len, info, &error, &bytes_read, FALSE); | |
362 | if (error) | |
363 | return -1; | |
364 | len += bytes_read; | |
365 | prin (stream, " %ld", target_count); | |
366 | for (i = 0; i < target_count + 1; i++) | |
367 | { | |
368 | long target = 0; | |
369 | target = wasm_read_leb128 | |
370 | (pc + len, info, &error, &bytes_read, FALSE); | |
371 | if (error) | |
372 | return -1; | |
373 | len += bytes_read; | |
374 | prin (stream, " %ld", target); | |
375 | } | |
376 | break; | |
377 | ||
378 | case wasm_break: | |
379 | case wasm_break_if: | |
380 | depth = wasm_read_leb128 | |
381 | (pc + len, info, &error, &bytes_read, FALSE); | |
382 | if (error) | |
383 | return -1; | |
384 | len += bytes_read; | |
385 | prin (stream, " %ld", depth); | |
386 | break; | |
387 | ||
388 | case wasm_return: | |
389 | break; | |
390 | ||
391 | case wasm_constant_i32: | |
392 | case wasm_constant_i64: | |
393 | constant = wasm_read_leb128 | |
394 | (pc + len, info, &error, &bytes_read, TRUE); | |
395 | if (error) | |
396 | return -1; | |
397 | len += bytes_read; | |
398 | prin (stream, " %lld", constant); | |
399 | break; | |
400 | ||
401 | case wasm_constant_f32: | |
402 | /* This appears to be the best we can do, even though we're | |
403 | using host doubles for WebAssembly floats. */ | |
404 | ret = read_f32 (&fconstant, pc + len, info); | |
405 | if (ret < 0) | |
406 | return -1; | |
407 | len += ret; | |
408 | prin (stream, " %.*g", DECIMAL_DIG, fconstant); | |
409 | break; | |
410 | ||
411 | case wasm_constant_f64: | |
412 | ret = read_f64 (&fconstant, pc + len, info); | |
413 | if (ret < 0) | |
414 | return -1; | |
415 | len += ret; | |
416 | prin (stream, " %.*g", DECIMAL_DIG, fconstant); | |
417 | break; | |
418 | ||
419 | case wasm_call: | |
420 | index = wasm_read_leb128 | |
421 | (pc + len, info, &error, &bytes_read, FALSE); | |
422 | if (error) | |
423 | return -1; | |
424 | len += bytes_read; | |
425 | prin (stream, " "); | |
426 | private_data->section_prefix = ".space.function_index"; | |
427 | (*info->print_address_func) ((bfd_vma) index, info); | |
428 | private_data->section_prefix = NULL; | |
429 | break; | |
430 | ||
431 | case wasm_call_indirect: | |
432 | constant = wasm_read_leb128 | |
433 | (pc + len, info, &error, &bytes_read, FALSE); | |
434 | if (error) | |
435 | return -1; | |
436 | len += bytes_read; | |
437 | prin (stream, " %lld", constant); | |
438 | constant = wasm_read_leb128 | |
439 | (pc + len, info, &error, &bytes_read, FALSE); | |
440 | if (error) | |
441 | return -1; | |
442 | len += bytes_read; | |
443 | prin (stream, " %lld", constant); | |
444 | break; | |
445 | ||
446 | case wasm_get_local: | |
447 | case wasm_set_local: | |
448 | case wasm_tee_local: | |
449 | constant = wasm_read_leb128 | |
450 | (pc + len, info, &error, &bytes_read, FALSE); | |
451 | if (error) | |
452 | return -1; | |
453 | len += bytes_read; | |
454 | prin (stream, " %lld", constant); | |
455 | if (strcmp (op->name + 4, "local") == 0) | |
456 | { | |
457 | if (private_data->print_registers | |
458 | && constant >= 0 && constant < nlocals) | |
459 | prin (stream, " <%s>", locals[constant]); | |
460 | } | |
461 | else | |
462 | { | |
463 | if (private_data->print_well_known_globals | |
464 | && constant >= 0 && constant < nglobals) | |
465 | prin (stream, " <%s>", globals[constant]); | |
466 | } | |
467 | break; | |
468 | ||
469 | case wasm_grow_memory: | |
470 | case wasm_current_memory: | |
471 | constant = wasm_read_leb128 | |
472 | (pc + len, info, &error, &bytes_read, FALSE); | |
473 | if (error) | |
474 | return -1; | |
475 | len += bytes_read; | |
476 | prin (stream, " %lld", constant); | |
477 | break; | |
478 | ||
479 | case wasm_load: | |
480 | case wasm_store: | |
481 | flags = wasm_read_leb128 | |
482 | (pc + len, info, &error, &bytes_read, FALSE); | |
483 | if (error) | |
484 | return -1; | |
485 | len += bytes_read; | |
486 | offset = wasm_read_leb128 | |
487 | (pc + len, info, &error, &bytes_read, FALSE); | |
488 | if (error) | |
489 | return -1; | |
490 | len += bytes_read; | |
491 | prin (stream, " a=%ld %ld", flags, offset); | |
492 | } | |
493 | } | |
494 | return len; | |
495 | } | |
496 | ||
497 | /* Print valid disassembler options to STREAM. */ | |
498 | ||
499 | void | |
500 | print_wasm32_disassembler_options (FILE *stream) | |
501 | { | |
502 | unsigned int i, max_len = 0; | |
503 | ||
504 | fprintf (stream, _("\ | |
505 | The following WebAssembly-specific disassembler options are supported for use\n\ | |
506 | with the -M switch:\n")); | |
507 | ||
508 | for (i = 0; i < ARRAY_SIZE (options); i++) | |
509 | { | |
510 | unsigned int len = strlen (options[i].name); | |
511 | ||
512 | if (max_len < len) | |
513 | max_len = len; | |
514 | } | |
515 | ||
516 | for (i = 0, max_len++; i < ARRAY_SIZE (options); i++) | |
517 | fprintf (stream, " %s%*c %s\n", | |
518 | options[i].name, | |
519 | (int)(max_len - strlen (options[i].name)), ' ', | |
520 | _(options[i].description)); | |
521 | } |