| 1 | /* Demangler for the Rust programming language |
| 2 | Copyright (C) 2016-2020 Free Software Foundation, Inc. |
| 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 | |
| 36 | #include <inttypes.h> |
| 37 | #include <sys/types.h> |
| 38 | #include <string.h> |
| 39 | #include <stdio.h> |
| 40 | #include <stdlib.h> |
| 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 | |
| 53 | struct rust_demangler |
| 54 | { |
| 55 | const char *sym; |
| 56 | size_t sym_len; |
| 57 | |
| 58 | void *callback_opaque; |
| 59 | demangle_callbackref callback; |
| 60 | |
| 61 | /* Position of the next character to read from the symbol. */ |
| 62 | size_t next; |
| 63 | |
| 64 | /* Non-zero if any error occurred. */ |
| 65 | int errored; |
| 66 | |
| 67 | /* Non-zero if printing should be verbose (e.g. include hashes). */ |
| 68 | int verbose; |
| 69 | |
| 70 | /* Rust mangling version, with legacy mangling being -1. */ |
| 71 | int version; |
| 72 | }; |
| 73 | |
| 74 | /* Parsing functions. */ |
| 75 | |
| 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 | } |
| 83 | |
| 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 | } |
| 94 | |
| 95 | struct rust_mangled_ident |
| 96 | { |
| 97 | /* ASCII part of the identifier. */ |
| 98 | const char *ascii; |
| 99 | size_t ascii_len; |
| 100 | }; |
| 101 | |
| 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 | } |
| 141 | |
| 142 | /* Printing functions. */ |
| 143 | |
| 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 | } |
| 150 | |
| 151 | #define PRINT(s) print_str (rdm, s, strlen (s)) |
| 152 | |
| 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) |
| 156 | { |
| 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 | } |
| 163 | |
| 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; |
| 171 | |
| 172 | if (len < 3 || e[0] != '$') |
| 173 | return 0; |
| 174 | |
| 175 | e++; |
| 176 | len--; |
| 177 | |
| 178 | if (e[0] == 'C') |
| 179 | { |
| 180 | escape_len = 1; |
| 181 | |
| 182 | c = ','; |
| 183 | } |
| 184 | else if (len > 2) |
| 185 | { |
| 186 | escape_len = 2; |
| 187 | |
| 188 | if (e[0] == 'S' && e[1] == 'P') |
| 189 | c = '@'; |
| 190 | else if (e[0] == 'B' && e[1] == 'P') |
| 191 | c = '*'; |
| 192 | else if (e[0] == 'R' && e[1] == 'F') |
| 193 | c = '&'; |
| 194 | else if (e[0] == 'L' && e[1] == 'T') |
| 195 | c = '<'; |
| 196 | else if (e[0] == 'G' && e[1] == 'T') |
| 197 | c = '>'; |
| 198 | else if (e[0] == 'L' && e[1] == 'P') |
| 199 | c = '('; |
| 200 | else if (e[0] == 'R' && e[1] == 'P') |
| 201 | c = ')'; |
| 202 | else if (e[0] == 'u' && len > 3) |
| 203 | { |
| 204 | escape_len = 3; |
| 205 | |
| 206 | hi_nibble = decode_lower_hex_nibble (e[1]); |
| 207 | if (hi_nibble < 0) |
| 208 | return 0; |
| 209 | lo_nibble = decode_lower_hex_nibble (e[2]); |
| 210 | if (lo_nibble < 0) |
| 211 | return 0; |
| 212 | |
| 213 | /* Only allow non-control ASCII characters. */ |
| 214 | if (hi_nibble > 7) |
| 215 | return 0; |
| 216 | c = (hi_nibble << 4) | lo_nibble; |
| 217 | if (c < 0x20) |
| 218 | return 0; |
| 219 | } |
| 220 | } |
| 221 | |
| 222 | if (!c || len <= escape_len || e[escape_len] != '$') |
| 223 | return 0; |
| 224 | |
| 225 | *out_len = 2 + escape_len; |
| 226 | return c; |
| 227 | } |
| 228 | |
| 229 | static void |
| 230 | print_ident (struct rust_demangler *rdm, struct rust_mangled_ident ident) |
| 231 | { |
| 232 | char unescaped; |
| 233 | size_t len; |
| 234 | |
| 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. */ |
| 301 | static int |
| 302 | is_legacy_prefixed_hash (struct rust_mangled_ident ident) |
| 303 | { |
| 304 | uint16_t seen; |
| 305 | int nibble; |
| 306 | size_t i, count; |
| 307 | |
| 308 | if (ident.ascii_len != 17 || ident.ascii[0] != 'h') |
| 309 | return 0; |
| 310 | |
| 311 | seen = 0; |
| 312 | for (i = 0; i < 16; i++) |
| 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; |
| 330 | } |
| 331 | |
| 332 | int |
| 333 | rust_demangle_callback (const char *mangled, int options, |
| 334 | demangle_callbackref callback, void *opaque) |
| 335 | { |
| 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++; |
| 364 | |
| 365 | if (*p == '_' || ISALNUM (*p)) |
| 366 | continue; |
| 367 | |
| 368 | if (rdm.version == -1 && (*p == '$' || *p == '.' || *p == ':')) |
| 369 | continue; |
| 370 | |
| 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) |
| 437 | { |
| 438 | size_t available, min_new_cap, new_cap; |
| 439 | char *new_ptr; |
| 440 | |
| 441 | /* Allocation failed before. */ |
| 442 | if (buf->errored) |
| 443 | return; |
| 444 | |
| 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 | } |
| 491 | } |
| 492 | |
| 493 | static void |
| 494 | str_buf_append (struct str_buf *buf, const char *data, size_t len) |
| 495 | { |
| 496 | str_buf_reserve (buf, len); |
| 497 | if (buf->errored) |
| 498 | return; |
| 499 | |
| 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; |
| 520 | |
| 521 | success = rust_demangle_callback (mangled, options, |
| 522 | str_buf_demangle_callback, &out); |
| 523 | |
| 524 | if (!success) |
| 525 | { |
| 526 | free (out.ptr); |
| 527 | return NULL; |
| 528 | } |
| 529 | |
| 530 | str_buf_append (&out, "\0", 1); |
| 531 | return out.ptr; |
| 532 | } |