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535aade6 | 1 | /* Demangler for the Rust programming language |
533da483 | 2 | Copyright (C) 2016-2020 Free Software Foundation, Inc. |
535aade6 DT |
3 | Written by David Tolnay (dtolnay@gmail.com). |
4 | ||
5 | This file is part of the libiberty library. | |
6 | Libiberty is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Library General Public | |
8 | License as published by the Free Software Foundation; either | |
9 | version 2 of the License, or (at your option) any later version. | |
10 | ||
11 | In addition to the permissions in the GNU Library General Public | |
12 | License, the Free Software Foundation gives you unlimited permission | |
13 | to link the compiled version of this file into combinations with other | |
14 | programs, and to distribute those combinations without any restriction | |
15 | coming from the use of this file. (The Library Public License | |
16 | restrictions do apply in other respects; for example, they cover | |
17 | modification of the file, and distribution when not linked into a | |
18 | combined executable.) | |
19 | ||
20 | Libiberty is distributed in the hope that it will be useful, | |
21 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
22 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
23 | Library General Public License for more details. | |
24 | ||
25 | You should have received a copy of the GNU Library General Public | |
26 | License along with libiberty; see the file COPYING.LIB. | |
27 | If not, see <http://www.gnu.org/licenses/>. */ | |
28 | ||
29 | ||
30 | #ifdef HAVE_CONFIG_H | |
31 | #include "config.h" | |
32 | #endif | |
33 | ||
34 | #include "safe-ctype.h" | |
35 | ||
533da483 | 36 | #include <inttypes.h> |
535aade6 DT |
37 | #include <sys/types.h> |
38 | #include <string.h> | |
39 | #include <stdio.h> | |
533da483 | 40 | #include <stdlib.h> |
535aade6 DT |
41 | |
42 | #ifdef HAVE_STRING_H | |
43 | #include <string.h> | |
44 | #else | |
45 | extern size_t strlen(const char *s); | |
46 | extern int strncmp(const char *s1, const char *s2, size_t n); | |
47 | extern void *memset(void *s, int c, size_t n); | |
48 | #endif | |
49 | ||
50 | #include <demangle.h> | |
51 | #include "libiberty.h" | |
52 | ||
533da483 NC |
53 | struct rust_demangler |
54 | { | |
55 | const char *sym; | |
56 | size_t sym_len; | |
535aade6 | 57 | |
533da483 NC |
58 | void *callback_opaque; |
59 | demangle_callbackref callback; | |
535aade6 | 60 | |
533da483 NC |
61 | /* Position of the next character to read from the symbol. */ |
62 | size_t next; | |
535aade6 | 63 | |
533da483 NC |
64 | /* Non-zero if any error occurred. */ |
65 | int errored; | |
535aade6 | 66 | |
533da483 NC |
67 | /* Non-zero if printing should be verbose (e.g. include hashes). */ |
68 | int verbose; | |
535aade6 | 69 | |
533da483 NC |
70 | /* Rust mangling version, with legacy mangling being -1. */ |
71 | int version; | |
72 | }; | |
535aade6 | 73 | |
533da483 | 74 | /* Parsing functions. */ |
535aade6 | 75 | |
533da483 NC |
76 | static char |
77 | peek (const struct rust_demangler *rdm) | |
78 | { | |
79 | if (rdm->next < rdm->sym_len) | |
80 | return rdm->sym[rdm->next]; | |
81 | return 0; | |
82 | } | |
535aade6 | 83 | |
533da483 NC |
84 | static char |
85 | next (struct rust_demangler *rdm) | |
86 | { | |
87 | char c = peek (rdm); | |
88 | if (!c) | |
89 | rdm->errored = 1; | |
90 | else | |
91 | rdm->next++; | |
92 | return c; | |
93 | } | |
535aade6 | 94 | |
533da483 NC |
95 | struct rust_mangled_ident |
96 | { | |
97 | /* ASCII part of the identifier. */ | |
98 | const char *ascii; | |
99 | size_t ascii_len; | |
100 | }; | |
535aade6 | 101 | |
533da483 NC |
102 | static struct rust_mangled_ident |
103 | parse_ident (struct rust_demangler *rdm) | |
104 | { | |
105 | char c; | |
106 | size_t start, len; | |
107 | struct rust_mangled_ident ident; | |
108 | ||
109 | ident.ascii = NULL; | |
110 | ident.ascii_len = 0; | |
111 | ||
112 | c = next (rdm); | |
113 | if (!ISDIGIT (c)) | |
114 | { | |
115 | rdm->errored = 1; | |
116 | return ident; | |
117 | } | |
118 | len = c - '0'; | |
119 | ||
120 | if (c != '0') | |
121 | while (ISDIGIT (peek (rdm))) | |
122 | len = len * 10 + (next (rdm) - '0'); | |
123 | ||
124 | start = rdm->next; | |
125 | rdm->next += len; | |
126 | /* Check for overflows. */ | |
127 | if ((start > rdm->next) || (rdm->next > rdm->sym_len)) | |
128 | { | |
129 | rdm->errored = 1; | |
130 | return ident; | |
131 | } | |
132 | ||
133 | ident.ascii = rdm->sym + start; | |
134 | ident.ascii_len = len; | |
135 | ||
136 | if (ident.ascii_len == 0) | |
137 | ident.ascii = NULL; | |
138 | ||
139 | return ident; | |
140 | } | |
535aade6 | 141 | |
533da483 | 142 | /* Printing functions. */ |
535aade6 | 143 | |
533da483 NC |
144 | static void |
145 | print_str (struct rust_demangler *rdm, const char *data, size_t len) | |
146 | { | |
147 | if (!rdm->errored) | |
148 | rdm->callback (data, len, rdm->callback_opaque); | |
149 | } | |
535aade6 | 150 | |
533da483 | 151 | #define PRINT(s) print_str (rdm, s, strlen (s)) |
535aade6 | 152 | |
533da483 NC |
153 | /* Return a 0x0-0xf value if the char is 0-9a-f, and -1 otherwise. */ |
154 | static int | |
155 | decode_lower_hex_nibble (char nibble) | |
535aade6 | 156 | { |
533da483 NC |
157 | if ('0' <= nibble && nibble <= '9') |
158 | return nibble - '0'; | |
159 | if ('a' <= nibble && nibble <= 'f') | |
160 | return 0xa + (nibble - 'a'); | |
161 | return -1; | |
162 | } | |
535aade6 | 163 | |
533da483 NC |
164 | /* Return the unescaped character for a "$...$" escape, or 0 if invalid. */ |
165 | static char | |
166 | decode_legacy_escape (const char *e, size_t len, size_t *out_len) | |
167 | { | |
168 | char c = 0; | |
169 | size_t escape_len = 0; | |
170 | int lo_nibble = -1, hi_nibble = -1; | |
535aade6 | 171 | |
533da483 | 172 | if (len < 3 || e[0] != '$') |
535aade6 DT |
173 | return 0; |
174 | ||
533da483 NC |
175 | e++; |
176 | len--; | |
177 | ||
178 | if (e[0] == 'C') | |
179 | { | |
180 | escape_len = 1; | |
181 | ||
182 | c = ','; | |
183 | } | |
184 | else if (len > 2) | |
185 | { | |
186 | escape_len = 2; | |
187 | ||
188 | if (e[0] == 'S' && e[1] == 'P') | |
189 | c = '@'; | |
190 | else if (e[0] == 'B' && e[1] == 'P') | |
191 | c = '*'; | |
192 | else if (e[0] == 'R' && e[1] == 'F') | |
193 | c = '&'; | |
194 | else if (e[0] == 'L' && e[1] == 'T') | |
195 | c = '<'; | |
196 | else if (e[0] == 'G' && e[1] == 'T') | |
197 | c = '>'; | |
198 | else if (e[0] == 'L' && e[1] == 'P') | |
199 | c = '('; | |
200 | else if (e[0] == 'R' && e[1] == 'P') | |
201 | c = ')'; | |
202 | else if (e[0] == 'u' && len > 3) | |
203 | { | |
204 | escape_len = 3; | |
205 | ||
206 | hi_nibble = decode_lower_hex_nibble (e[1]); | |
207 | if (hi_nibble < 0) | |
208 | return 0; | |
209 | lo_nibble = decode_lower_hex_nibble (e[2]); | |
210 | if (lo_nibble < 0) | |
211 | return 0; | |
212 | ||
213 | /* Only allow non-control ASCII characters. */ | |
214 | if (hi_nibble > 7) | |
215 | return 0; | |
216 | c = (hi_nibble << 4) | lo_nibble; | |
217 | if (c < 0x20) | |
218 | return 0; | |
219 | } | |
220 | } | |
221 | ||
222 | if (!c || len <= escape_len || e[escape_len] != '$') | |
535aade6 DT |
223 | return 0; |
224 | ||
533da483 NC |
225 | *out_len = 2 + escape_len; |
226 | return c; | |
535aade6 DT |
227 | } |
228 | ||
533da483 NC |
229 | static void |
230 | print_ident (struct rust_demangler *rdm, struct rust_mangled_ident ident) | |
231 | { | |
232 | char unescaped; | |
233 | size_t len; | |
535aade6 | 234 | |
533da483 NC |
235 | if (rdm->errored) |
236 | return; | |
237 | ||
238 | if (rdm->version == -1) | |
239 | { | |
240 | /* Ignore leading underscores preceding escape sequences. | |
241 | The mangler inserts an underscore to make sure the | |
242 | identifier begins with a XID_Start character. */ | |
243 | if (ident.ascii_len >= 2 && ident.ascii[0] == '_' | |
244 | && ident.ascii[1] == '$') | |
245 | { | |
246 | ident.ascii++; | |
247 | ident.ascii_len--; | |
248 | } | |
249 | ||
250 | while (ident.ascii_len > 0) | |
251 | { | |
252 | /* Handle legacy escape sequences ("$...$", ".." or "."). */ | |
253 | if (ident.ascii[0] == '$') | |
254 | { | |
255 | unescaped | |
256 | = decode_legacy_escape (ident.ascii, ident.ascii_len, &len); | |
257 | if (unescaped) | |
258 | print_str (rdm, &unescaped, 1); | |
259 | else | |
260 | { | |
261 | /* Unexpected escape sequence, print the rest verbatim. */ | |
262 | print_str (rdm, ident.ascii, ident.ascii_len); | |
263 | return; | |
264 | } | |
265 | } | |
266 | else if (ident.ascii[0] == '.') | |
267 | { | |
268 | if (ident.ascii_len >= 2 && ident.ascii[1] == '.') | |
269 | { | |
270 | /* ".." becomes "::" */ | |
271 | PRINT ("::"); | |
272 | len = 2; | |
273 | } | |
274 | else | |
275 | { | |
276 | /* "." becomes "-" */ | |
277 | PRINT ("-"); | |
278 | len = 1; | |
279 | } | |
280 | } | |
281 | else | |
282 | { | |
283 | /* Print everything before the next escape sequence, at once. */ | |
284 | for (len = 0; len < ident.ascii_len; len++) | |
285 | if (ident.ascii[len] == '$' || ident.ascii[len] == '.') | |
286 | break; | |
287 | ||
288 | print_str (rdm, ident.ascii, len); | |
289 | } | |
290 | ||
291 | ident.ascii += len; | |
292 | ident.ascii_len -= len; | |
293 | } | |
294 | ||
295 | return; | |
296 | } | |
297 | } | |
298 | ||
299 | /* A legacy hash is the prefix "h" followed by 16 lowercase hex digits. | |
300 | The hex digits must contain at least 5 distinct digits. */ | |
535aade6 | 301 | static int |
533da483 | 302 | is_legacy_prefixed_hash (struct rust_mangled_ident ident) |
535aade6 | 303 | { |
533da483 NC |
304 | uint16_t seen; |
305 | int nibble; | |
306 | size_t i, count; | |
535aade6 | 307 | |
533da483 | 308 | if (ident.ascii_len != 17 || ident.ascii[0] != 'h') |
535aade6 | 309 | return 0; |
535aade6 | 310 | |
533da483 | 311 | seen = 0; |
535aade6 | 312 | for (i = 0; i < 16; i++) |
533da483 NC |
313 | { |
314 | nibble = decode_lower_hex_nibble (ident.ascii[1 + i]); | |
315 | if (nibble < 0) | |
316 | return 0; | |
317 | seen |= (uint16_t)1 << nibble; | |
318 | } | |
319 | ||
320 | /* Count how many distinct digits were seen. */ | |
321 | count = 0; | |
322 | while (seen) | |
323 | { | |
324 | if (seen & 1) | |
325 | count++; | |
326 | seen >>= 1; | |
327 | } | |
328 | ||
329 | return count >= 5; | |
535aade6 DT |
330 | } |
331 | ||
533da483 NC |
332 | int |
333 | rust_demangle_callback (const char *mangled, int options, | |
334 | demangle_callbackref callback, void *opaque) | |
535aade6 | 335 | { |
533da483 NC |
336 | const char *p; |
337 | struct rust_demangler rdm; | |
338 | struct rust_mangled_ident ident; | |
339 | ||
340 | rdm.sym = mangled; | |
341 | rdm.sym_len = 0; | |
342 | ||
343 | rdm.callback_opaque = opaque; | |
344 | rdm.callback = callback; | |
345 | ||
346 | rdm.next = 0; | |
347 | rdm.errored = 0; | |
348 | rdm.verbose = (options & DMGL_VERBOSE) != 0; | |
349 | rdm.version = 0; | |
350 | ||
351 | /* Rust symbols always start with _ZN (legacy). */ | |
352 | if (rdm.sym[0] == '_' && rdm.sym[1] == 'Z' && rdm.sym[2] == 'N') | |
353 | { | |
354 | rdm.sym += 3; | |
355 | rdm.version = -1; | |
356 | } | |
357 | else | |
358 | return 0; | |
359 | ||
360 | /* Legacy Rust symbols use only [_0-9a-zA-Z.:$] characters. */ | |
361 | for (p = rdm.sym; *p; p++) | |
362 | { | |
363 | rdm.sym_len++; | |
535aade6 | 364 | |
533da483 NC |
365 | if (*p == '_' || ISALNUM (*p)) |
366 | continue; | |
535aade6 | 367 | |
533da483 NC |
368 | if (rdm.version == -1 && (*p == '$' || *p == '.' || *p == ':')) |
369 | continue; | |
535aade6 | 370 | |
533da483 NC |
371 | return 0; |
372 | } | |
373 | ||
374 | /* Legacy Rust symbols need to be handled separately. */ | |
375 | if (rdm.version == -1) | |
376 | { | |
377 | /* Legacy Rust symbols always end with E. */ | |
378 | if (!(rdm.sym_len > 0 && rdm.sym[rdm.sym_len - 1] == 'E')) | |
379 | return 0; | |
380 | rdm.sym_len--; | |
381 | ||
382 | /* Legacy Rust symbols also always end with a path segment | |
383 | that encodes a 16 hex digit hash, i.e. '17h[a-f0-9]{16}'. | |
384 | This early check, before any parse_ident calls, should | |
385 | quickly filter out most C++ symbols unrelated to Rust. */ | |
386 | if (!(rdm.sym_len > 19 | |
387 | && !memcmp (&rdm.sym[rdm.sym_len - 19], "17h", 3))) | |
388 | return 0; | |
389 | ||
390 | do | |
391 | { | |
392 | ident = parse_ident (&rdm); | |
393 | if (rdm.errored || !ident.ascii) | |
394 | return 0; | |
395 | } | |
396 | while (rdm.next < rdm.sym_len); | |
397 | ||
398 | /* The last path segment should be the hash. */ | |
399 | if (!is_legacy_prefixed_hash (ident)) | |
400 | return 0; | |
401 | ||
402 | /* Reset the state for a second pass, to print the symbol. */ | |
403 | rdm.next = 0; | |
404 | if (!rdm.verbose && rdm.sym_len > 19) | |
405 | { | |
406 | /* Hide the last segment, containing the hash, if not verbose. */ | |
407 | rdm.sym_len -= 19; | |
408 | } | |
409 | ||
410 | do | |
411 | { | |
412 | if (rdm.next > 0) | |
413 | print_str (&rdm, "::", 2); | |
414 | ||
415 | ident = parse_ident (&rdm); | |
416 | print_ident (&rdm, ident); | |
417 | } | |
418 | while (rdm.next < rdm.sym_len); | |
419 | } | |
420 | else | |
421 | return 0; | |
422 | ||
423 | return !rdm.errored; | |
424 | } | |
425 | ||
426 | /* Growable string buffers. */ | |
427 | struct str_buf | |
428 | { | |
429 | char *ptr; | |
430 | size_t len; | |
431 | size_t cap; | |
432 | int errored; | |
433 | }; | |
434 | ||
435 | static void | |
436 | str_buf_reserve (struct str_buf *buf, size_t extra) | |
535aade6 | 437 | { |
533da483 NC |
438 | size_t available, min_new_cap, new_cap; |
439 | char *new_ptr; | |
535aade6 | 440 | |
533da483 NC |
441 | /* Allocation failed before. */ |
442 | if (buf->errored) | |
535aade6 DT |
443 | return; |
444 | ||
533da483 NC |
445 | available = buf->cap - buf->len; |
446 | ||
447 | if (extra <= available) | |
448 | return; | |
449 | ||
450 | min_new_cap = buf->cap + (extra - available); | |
451 | ||
452 | /* Check for overflows. */ | |
453 | if (min_new_cap < buf->cap) | |
454 | { | |
455 | buf->errored = 1; | |
456 | return; | |
457 | } | |
458 | ||
459 | new_cap = buf->cap; | |
460 | ||
461 | if (new_cap == 0) | |
462 | new_cap = 4; | |
463 | ||
464 | /* Double capacity until sufficiently large. */ | |
465 | while (new_cap < min_new_cap) | |
466 | { | |
467 | new_cap *= 2; | |
468 | ||
469 | /* Check for overflows. */ | |
470 | if (new_cap < buf->cap) | |
471 | { | |
472 | buf->errored = 1; | |
473 | return; | |
474 | } | |
475 | } | |
476 | ||
477 | new_ptr = (char *)realloc (buf->ptr, new_cap); | |
478 | if (new_ptr == NULL) | |
479 | { | |
480 | free (buf->ptr); | |
481 | buf->ptr = NULL; | |
482 | buf->len = 0; | |
483 | buf->cap = 0; | |
484 | buf->errored = 1; | |
485 | } | |
486 | else | |
487 | { | |
488 | buf->ptr = new_ptr; | |
489 | buf->cap = new_cap; | |
490 | } | |
535aade6 DT |
491 | } |
492 | ||
533da483 NC |
493 | static void |
494 | str_buf_append (struct str_buf *buf, const char *data, size_t len) | |
535aade6 | 495 | { |
533da483 NC |
496 | str_buf_reserve (buf, len); |
497 | if (buf->errored) | |
498 | return; | |
535aade6 | 499 | |
533da483 NC |
500 | memcpy (buf->ptr + buf->len, data, len); |
501 | buf->len += len; | |
502 | } | |
503 | ||
504 | static void | |
505 | str_buf_demangle_callback (const char *data, size_t len, void *opaque) | |
506 | { | |
507 | str_buf_append ((struct str_buf *)opaque, data, len); | |
508 | } | |
509 | ||
510 | char * | |
511 | rust_demangle (const char *mangled, int options) | |
512 | { | |
513 | struct str_buf out; | |
514 | int success; | |
515 | ||
516 | out.ptr = NULL; | |
517 | out.len = 0; | |
518 | out.cap = 0; | |
519 | out.errored = 0; | |
535aade6 | 520 | |
533da483 NC |
521 | success = rust_demangle_callback (mangled, options, |
522 | str_buf_demangle_callback, &out); | |
535aade6 | 523 | |
533da483 NC |
524 | if (!success) |
525 | { | |
526 | free (out.ptr); | |
527 | return NULL; | |
528 | } | |
535aade6 | 529 | |
533da483 NC |
530 | str_buf_append (&out, "\0", 1); |
531 | return out.ptr; | |
535aade6 | 532 | } |