lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* Subroutines needed for unwinding stack frames for exception handling. */ |
| 2 | /* Copyright (C) 1997-2015 Free Software Foundation, Inc. |
| 3 | Contributed by Jason Merrill <jason@cygnus.com>. |
| 4 | |
| 5 | This file is part of the GNU C Library. |
| 6 | |
| 7 | The GNU C Library is free software; you can redistribute it and/or |
| 8 | modify it under the terms of the GNU Lesser General Public |
| 9 | License as published by the Free Software Foundation; either |
| 10 | version 2.1 of the License, or (at your option) any later version. |
| 11 | |
| 12 | The GNU C Library is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | Lesser General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU Lesser General Public |
| 18 | License along with the GNU C Library; if not, see |
| 19 | <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | #ifdef _LIBC |
| 22 | # include <shlib-compat.h> |
| 23 | #endif |
| 24 | |
| 25 | #if !defined _LIBC || SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2_5) |
| 26 | |
| 27 | #ifdef _LIBC |
| 28 | #include <stdlib.h> |
| 29 | #include <string.h> |
| 30 | #include <bits/libc-lock.h> |
| 31 | #include <dwarf2.h> |
| 32 | #include <unwind.h> |
| 33 | #define NO_BASE_OF_ENCODED_VALUE |
| 34 | #include <unwind-pe.h> |
| 35 | #include <unwind-dw2-fde.h> |
| 36 | #else |
| 37 | #ifndef _Unwind_Find_FDE |
| 38 | #include "tconfig.h" |
| 39 | #include "tsystem.h" |
| 40 | #include "dwarf2.h" |
| 41 | #include "unwind.h" |
| 42 | #define NO_BASE_OF_ENCODED_VALUE |
| 43 | #include "unwind-pe.h" |
| 44 | #include "unwind-dw2-fde.h" |
| 45 | #include "gthr.h" |
| 46 | #endif |
| 47 | #endif |
| 48 | |
| 49 | /* The unseen_objects list contains objects that have been registered |
| 50 | but not yet categorized in any way. The seen_objects list has had |
| 51 | it's pc_begin and count fields initialized at minimum, and is sorted |
| 52 | by decreasing value of pc_begin. */ |
| 53 | static struct object *unseen_objects; |
| 54 | static struct object *seen_objects; |
| 55 | |
| 56 | #ifdef _LIBC |
| 57 | |
| 58 | __libc_lock_define_initialized (static, object_mutex) |
| 59 | #define init_object_mutex_once() |
| 60 | #define __gthread_mutex_lock(m) __libc_lock_lock (*(m)) |
| 61 | #define __gthread_mutex_unlock(m) __libc_lock_unlock (*(m)) |
| 62 | |
| 63 | void __register_frame_info_bases (void *begin, struct object *ob, |
| 64 | void *tbase, void *dbase); |
| 65 | hidden_proto (__register_frame_info_bases) |
| 66 | void __register_frame_info_table_bases (void *begin, |
| 67 | struct object *ob, |
| 68 | void *tbase, void *dbase); |
| 69 | hidden_proto (__register_frame_info_table_bases) |
| 70 | void *__deregister_frame_info_bases (void *begin); |
| 71 | hidden_proto (__deregister_frame_info_bases) |
| 72 | |
| 73 | #else |
| 74 | |
| 75 | #ifdef __GTHREAD_MUTEX_INIT |
| 76 | static __gthread_mutex_t object_mutex = __GTHREAD_MUTEX_INIT; |
| 77 | #else |
| 78 | static __gthread_mutex_t object_mutex; |
| 79 | #endif |
| 80 | |
| 81 | #ifdef __GTHREAD_MUTEX_INIT_FUNCTION |
| 82 | static void |
| 83 | init_object_mutex (void) |
| 84 | { |
| 85 | __GTHREAD_MUTEX_INIT_FUNCTION (&object_mutex); |
| 86 | } |
| 87 | |
| 88 | static void |
| 89 | init_object_mutex_once (void) |
| 90 | { |
| 91 | static __gthread_once_t once = __GTHREAD_ONCE_INIT; |
| 92 | __gthread_once (&once, init_object_mutex); |
| 93 | } |
| 94 | #else |
| 95 | #define init_object_mutex_once() |
| 96 | #endif |
| 97 | |
| 98 | #endif /* _LIBC */ |
| 99 | |
| 100 | /* Called from crtbegin.o to register the unwind info for an object. */ |
| 101 | |
| 102 | void |
| 103 | __register_frame_info_bases (void *begin, struct object *ob, |
| 104 | void *tbase, void *dbase) |
| 105 | { |
| 106 | /* If .eh_frame is empty, don't register at all. */ |
| 107 | if (*(uword *) begin == 0) |
| 108 | return; |
| 109 | |
| 110 | ob->pc_begin = (void *)-1; |
| 111 | ob->tbase = tbase; |
| 112 | ob->dbase = dbase; |
| 113 | ob->u.single = begin; |
| 114 | ob->s.i = 0; |
| 115 | ob->s.b.encoding = DW_EH_PE_omit; |
| 116 | #ifdef DWARF2_OBJECT_END_PTR_EXTENSION |
| 117 | ob->fde_end = NULL; |
| 118 | #endif |
| 119 | |
| 120 | init_object_mutex_once (); |
| 121 | __gthread_mutex_lock (&object_mutex); |
| 122 | |
| 123 | ob->next = unseen_objects; |
| 124 | unseen_objects = ob; |
| 125 | |
| 126 | __gthread_mutex_unlock (&object_mutex); |
| 127 | } |
| 128 | hidden_def (__register_frame_info_bases) |
| 129 | |
| 130 | void |
| 131 | __register_frame_info (void *begin, struct object *ob) |
| 132 | { |
| 133 | __register_frame_info_bases (begin, ob, 0, 0); |
| 134 | } |
| 135 | |
| 136 | void |
| 137 | __register_frame (void *begin) |
| 138 | { |
| 139 | struct object *ob; |
| 140 | |
| 141 | /* If .eh_frame is empty, don't register at all. */ |
| 142 | if (*(uword *) begin == 0) |
| 143 | return; |
| 144 | |
| 145 | ob = (struct object *) malloc (sizeof (struct object)); |
| 146 | __register_frame_info_bases (begin, ob, 0, 0); |
| 147 | } |
| 148 | |
| 149 | /* Similar, but BEGIN is actually a pointer to a table of unwind entries |
| 150 | for different translation units. Called from the file generated by |
| 151 | collect2. */ |
| 152 | |
| 153 | void |
| 154 | __register_frame_info_table_bases (void *begin, struct object *ob, |
| 155 | void *tbase, void *dbase) |
| 156 | { |
| 157 | ob->pc_begin = (void *)-1; |
| 158 | ob->tbase = tbase; |
| 159 | ob->dbase = dbase; |
| 160 | ob->u.array = begin; |
| 161 | ob->s.i = 0; |
| 162 | ob->s.b.from_array = 1; |
| 163 | ob->s.b.encoding = DW_EH_PE_omit; |
| 164 | |
| 165 | init_object_mutex_once (); |
| 166 | __gthread_mutex_lock (&object_mutex); |
| 167 | |
| 168 | ob->next = unseen_objects; |
| 169 | unseen_objects = ob; |
| 170 | |
| 171 | __gthread_mutex_unlock (&object_mutex); |
| 172 | } |
| 173 | hidden_def (__register_frame_info_table_bases) |
| 174 | |
| 175 | void |
| 176 | __register_frame_info_table (void *begin, struct object *ob) |
| 177 | { |
| 178 | __register_frame_info_table_bases (begin, ob, 0, 0); |
| 179 | } |
| 180 | |
| 181 | void |
| 182 | __register_frame_table (void *begin) |
| 183 | { |
| 184 | struct object *ob = (struct object *) malloc (sizeof (struct object)); |
| 185 | __register_frame_info_table_bases (begin, ob, 0, 0); |
| 186 | } |
| 187 | |
| 188 | /* Called from crtbegin.o to deregister the unwind info for an object. */ |
| 189 | /* ??? Glibc has for a while now exported __register_frame_info and |
| 190 | __deregister_frame_info. If we call __register_frame_info_bases |
| 191 | from crtbegin (wherein it is declared weak), and this object does |
| 192 | not get pulled from libgcc.a for other reasons, then the |
| 193 | invocation of __deregister_frame_info will be resolved from glibc. |
| 194 | Since the registration did not happen there, we'll abort. |
| 195 | |
| 196 | Therefore, declare a new deregistration entry point that does the |
| 197 | exact same thing, but will resolve to the same library as |
| 198 | implements __register_frame_info_bases. */ |
| 199 | |
| 200 | void * |
| 201 | __deregister_frame_info_bases (void *begin) |
| 202 | { |
| 203 | struct object **p; |
| 204 | struct object *ob = 0; |
| 205 | |
| 206 | /* If .eh_frame is empty, we haven't registered. */ |
| 207 | if (*(uword *) begin == 0) |
| 208 | return ob; |
| 209 | |
| 210 | init_object_mutex_once (); |
| 211 | __gthread_mutex_lock (&object_mutex); |
| 212 | |
| 213 | for (p = &unseen_objects; *p ; p = &(*p)->next) |
| 214 | if ((*p)->u.single == begin) |
| 215 | { |
| 216 | ob = *p; |
| 217 | *p = ob->next; |
| 218 | goto out; |
| 219 | } |
| 220 | |
| 221 | for (p = &seen_objects; *p ; p = &(*p)->next) |
| 222 | if ((*p)->s.b.sorted) |
| 223 | { |
| 224 | if ((*p)->u.sort->orig_data == begin) |
| 225 | { |
| 226 | ob = *p; |
| 227 | *p = ob->next; |
| 228 | free (ob->u.sort); |
| 229 | goto out; |
| 230 | } |
| 231 | } |
| 232 | else |
| 233 | { |
| 234 | if ((*p)->u.single == begin) |
| 235 | { |
| 236 | ob = *p; |
| 237 | *p = ob->next; |
| 238 | goto out; |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | __gthread_mutex_unlock (&object_mutex); |
| 243 | abort (); |
| 244 | |
| 245 | out: |
| 246 | __gthread_mutex_unlock (&object_mutex); |
| 247 | return (void *) ob; |
| 248 | } |
| 249 | hidden_def (__deregister_frame_info_bases) |
| 250 | |
| 251 | void * |
| 252 | __deregister_frame_info (void *begin) |
| 253 | { |
| 254 | return __deregister_frame_info_bases (begin); |
| 255 | } |
| 256 | |
| 257 | void |
| 258 | __deregister_frame (void *begin) |
| 259 | { |
| 260 | /* If .eh_frame is empty, we haven't registered. */ |
| 261 | if (*(uword *) begin != 0) |
| 262 | free (__deregister_frame_info_bases (begin)); |
| 263 | } |
| 264 | |
| 265 | |
| 266 | /* Like base_of_encoded_value, but take the base from a struct object |
| 267 | instead of an _Unwind_Context. */ |
| 268 | |
| 269 | static _Unwind_Ptr |
| 270 | base_from_object (unsigned char encoding, struct object *ob) |
| 271 | { |
| 272 | if (encoding == DW_EH_PE_omit) |
| 273 | return 0; |
| 274 | |
| 275 | switch (encoding & 0x70) |
| 276 | { |
| 277 | case DW_EH_PE_absptr: |
| 278 | case DW_EH_PE_pcrel: |
| 279 | case DW_EH_PE_aligned: |
| 280 | return 0; |
| 281 | |
| 282 | case DW_EH_PE_textrel: |
| 283 | return (_Unwind_Ptr) ob->tbase; |
| 284 | case DW_EH_PE_datarel: |
| 285 | return (_Unwind_Ptr) ob->dbase; |
| 286 | } |
| 287 | abort (); |
| 288 | } |
| 289 | |
| 290 | /* Return the FDE pointer encoding from the CIE. */ |
| 291 | /* ??? This is a subset of extract_cie_info from unwind-dw2.c. */ |
| 292 | |
| 293 | static int |
| 294 | get_cie_encoding (struct dwarf_cie *cie) |
| 295 | { |
| 296 | const unsigned char *aug, *p; |
| 297 | _Unwind_Ptr dummy; |
| 298 | _Unwind_Word utmp; |
| 299 | _Unwind_Sword stmp; |
| 300 | |
| 301 | aug = cie->augmentation; |
| 302 | if (aug[0] != 'z') |
| 303 | return DW_EH_PE_absptr; |
| 304 | |
| 305 | /* Skip the augmentation string. */ |
| 306 | p = aug + strlen ((const char *) aug) + 1; |
| 307 | p = read_uleb128 (p, &utmp); /* Skip code alignment. */ |
| 308 | p = read_sleb128 (p, &stmp); /* Skip data alignment. */ |
| 309 | p++; /* Skip return address column. */ |
| 310 | |
| 311 | aug++; /* Skip 'z' */ |
| 312 | p = read_uleb128 (p, &utmp); /* Skip augmentation length. */ |
| 313 | while (1) |
| 314 | { |
| 315 | /* This is what we're looking for. */ |
| 316 | if (*aug == 'R') |
| 317 | return *p; |
| 318 | /* Personality encoding and pointer. */ |
| 319 | else if (*aug == 'P') |
| 320 | { |
| 321 | /* ??? Avoid dereferencing indirect pointers, since we're |
| 322 | faking the base address. Gotta keep DW_EH_PE_aligned |
| 323 | intact, however. */ |
| 324 | p = read_encoded_value_with_base (*p & 0x7F, 0, p + 1, &dummy); |
| 325 | } |
| 326 | /* LSDA encoding. */ |
| 327 | else if (*aug == 'L') |
| 328 | p++; |
| 329 | /* Otherwise end of string, or unknown augmentation. */ |
| 330 | else |
| 331 | return DW_EH_PE_absptr; |
| 332 | aug++; |
| 333 | } |
| 334 | } |
| 335 | |
| 336 | static inline int |
| 337 | get_fde_encoding (struct dwarf_fde *f) |
| 338 | { |
| 339 | return get_cie_encoding (get_cie (f)); |
| 340 | } |
| 341 | |
| 342 | |
| 343 | /* Sorting an array of FDEs by address. |
| 344 | (Ideally we would have the linker sort the FDEs so we don't have to do |
| 345 | it at run time. But the linkers are not yet prepared for this.) */ |
| 346 | |
| 347 | /* Return the Nth pc_begin value from FDE x. */ |
| 348 | |
| 349 | static inline _Unwind_Ptr |
| 350 | get_pc_begin (fde *x, size_t n) |
| 351 | { |
| 352 | _Unwind_Ptr p; |
| 353 | memcpy (&p, x->pc_begin + n * sizeof (_Unwind_Ptr), sizeof (_Unwind_Ptr)); |
| 354 | return p; |
| 355 | } |
| 356 | |
| 357 | /* Comparison routines. Three variants of increasing complexity. */ |
| 358 | |
| 359 | static int |
| 360 | fde_unencoded_compare (struct object *ob __attribute__((unused)), |
| 361 | fde *x, fde *y) |
| 362 | { |
| 363 | _Unwind_Ptr x_ptr = get_pc_begin (x, 0); |
| 364 | _Unwind_Ptr y_ptr = get_pc_begin (y, 0); |
| 365 | |
| 366 | if (x_ptr > y_ptr) |
| 367 | return 1; |
| 368 | if (x_ptr < y_ptr) |
| 369 | return -1; |
| 370 | return 0; |
| 371 | } |
| 372 | |
| 373 | static int |
| 374 | fde_single_encoding_compare (struct object *ob, fde *x, fde *y) |
| 375 | { |
| 376 | _Unwind_Ptr base, x_ptr, y_ptr; |
| 377 | |
| 378 | base = base_from_object (ob->s.b.encoding, ob); |
| 379 | read_encoded_value_with_base (ob->s.b.encoding, base, x->pc_begin, &x_ptr); |
| 380 | read_encoded_value_with_base (ob->s.b.encoding, base, y->pc_begin, &y_ptr); |
| 381 | |
| 382 | if (x_ptr > y_ptr) |
| 383 | return 1; |
| 384 | if (x_ptr < y_ptr) |
| 385 | return -1; |
| 386 | return 0; |
| 387 | } |
| 388 | |
| 389 | static int |
| 390 | fde_mixed_encoding_compare (struct object *ob, fde *x, fde *y) |
| 391 | { |
| 392 | int x_encoding, y_encoding; |
| 393 | _Unwind_Ptr x_ptr, y_ptr; |
| 394 | |
| 395 | x_encoding = get_fde_encoding (x); |
| 396 | read_encoded_value_with_base (x_encoding, base_from_object (x_encoding, ob), |
| 397 | x->pc_begin, &x_ptr); |
| 398 | |
| 399 | y_encoding = get_fde_encoding (y); |
| 400 | read_encoded_value_with_base (y_encoding, base_from_object (y_encoding, ob), |
| 401 | y->pc_begin, &y_ptr); |
| 402 | |
| 403 | if (x_ptr > y_ptr) |
| 404 | return 1; |
| 405 | if (x_ptr < y_ptr) |
| 406 | return -1; |
| 407 | return 0; |
| 408 | } |
| 409 | |
| 410 | typedef int (*fde_compare_t) (struct object *, fde *, fde *); |
| 411 | |
| 412 | |
| 413 | /* This is a special mix of insertion sort and heap sort, optimized for |
| 414 | the data sets that actually occur. They look like |
| 415 | 101 102 103 127 128 105 108 110 190 111 115 119 125 160 126 129 130. |
| 416 | I.e. a linearly increasing sequence (coming from functions in the text |
| 417 | section), with additionally a few unordered elements (coming from functions |
| 418 | in gnu_linkonce sections) whose values are higher than the values in the |
| 419 | surrounding linear sequence (but not necessarily higher than the values |
| 420 | at the end of the linear sequence!). |
| 421 | The worst-case total run time is O(N) + O(n log (n)), where N is the |
| 422 | total number of FDEs and n is the number of erratic ones. */ |
| 423 | |
| 424 | struct fde_accumulator |
| 425 | { |
| 426 | struct fde_vector *linear; |
| 427 | struct fde_vector *erratic; |
| 428 | }; |
| 429 | |
| 430 | static int |
| 431 | start_fde_sort (struct fde_accumulator *accu, size_t count) |
| 432 | { |
| 433 | size_t size; |
| 434 | if (! count) |
| 435 | return 0; |
| 436 | |
| 437 | size = sizeof (struct fde_vector) + sizeof (fde *) * count; |
| 438 | if ((accu->linear = (struct fde_vector *) malloc (size))) |
| 439 | { |
| 440 | accu->linear->count = 0; |
| 441 | if ((accu->erratic = (struct fde_vector *) malloc (size))) |
| 442 | accu->erratic->count = 0; |
| 443 | return 1; |
| 444 | } |
| 445 | else |
| 446 | return 0; |
| 447 | } |
| 448 | |
| 449 | static inline void |
| 450 | fde_insert (struct fde_accumulator *accu, fde *this_fde) |
| 451 | { |
| 452 | if (accu->linear) |
| 453 | accu->linear->array[accu->linear->count++] = this_fde; |
| 454 | } |
| 455 | |
| 456 | /* Split LINEAR into a linear sequence with low values and an erratic |
| 457 | sequence with high values, put the linear one (of longest possible |
| 458 | length) into LINEAR and the erratic one into ERRATIC. This is O(N). |
| 459 | |
| 460 | Because the longest linear sequence we are trying to locate within the |
| 461 | incoming LINEAR array can be interspersed with (high valued) erratic |
| 462 | entries. We construct a chain indicating the sequenced entries. |
| 463 | To avoid having to allocate this chain, we overlay it onto the space of |
| 464 | the ERRATIC array during construction. A final pass iterates over the |
| 465 | chain to determine what should be placed in the ERRATIC array, and |
| 466 | what is the linear sequence. This overlay is safe from aliasing. */ |
| 467 | |
| 468 | static void |
| 469 | fde_split (struct object *ob, fde_compare_t fde_compare, |
| 470 | struct fde_vector *linear, struct fde_vector *erratic) |
| 471 | { |
| 472 | static fde *marker; |
| 473 | size_t count = linear->count; |
| 474 | fde **chain_end = ▮ |
| 475 | size_t i, j, k; |
| 476 | |
| 477 | /* This should optimize out, but it is wise to make sure this assumption |
| 478 | is correct. Should these have different sizes, we cannot cast between |
| 479 | them and the overlaying onto ERRATIC will not work. */ |
| 480 | if (sizeof (fde *) != sizeof (fde **)) |
| 481 | abort (); |
| 482 | |
| 483 | for (i = 0; i < count; i++) |
| 484 | { |
| 485 | fde **probe; |
| 486 | |
| 487 | for (probe = chain_end; |
| 488 | probe != &marker && fde_compare (ob, linear->array[i], *probe) < 0; |
| 489 | probe = chain_end) |
| 490 | { |
| 491 | chain_end = (fde **) erratic->array[probe - linear->array]; |
| 492 | erratic->array[probe - linear->array] = NULL; |
| 493 | } |
| 494 | erratic->array[i] = (fde *) chain_end; |
| 495 | chain_end = &linear->array[i]; |
| 496 | } |
| 497 | |
| 498 | /* Each entry in LINEAR which is part of the linear sequence we have |
| 499 | discovered will correspond to a non-NULL entry in the chain we built in |
| 500 | the ERRATIC array. */ |
| 501 | for (i = j = k = 0; i < count; i++) |
| 502 | if (erratic->array[i]) |
| 503 | linear->array[j++] = linear->array[i]; |
| 504 | else |
| 505 | erratic->array[k++] = linear->array[i]; |
| 506 | linear->count = j; |
| 507 | erratic->count = k; |
| 508 | } |
| 509 | |
| 510 | /* This is O(n log(n)). BSD/OS defines heapsort in stdlib.h, so we must |
| 511 | use a name that does not conflict. */ |
| 512 | |
| 513 | static void |
| 514 | frame_heapsort (struct object *ob, fde_compare_t fde_compare, |
| 515 | struct fde_vector *erratic) |
| 516 | { |
| 517 | /* For a description of this algorithm, see: |
| 518 | Samuel P. Harbison, Guy L. Steele Jr.: C, a reference manual, 2nd ed., |
| 519 | p. 60-61. */ |
| 520 | fde ** a = erratic->array; |
| 521 | /* A portion of the array is called a "heap" if for all i>=0: |
| 522 | If i and 2i+1 are valid indices, then a[i] >= a[2i+1]. |
| 523 | If i and 2i+2 are valid indices, then a[i] >= a[2i+2]. */ |
| 524 | #define SWAP(x,y) do { fde * tmp = x; x = y; y = tmp; } while (0) |
| 525 | size_t n = erratic->count; |
| 526 | size_t m = n; |
| 527 | size_t i; |
| 528 | |
| 529 | while (m > 0) |
| 530 | { |
| 531 | /* Invariant: a[m..n-1] is a heap. */ |
| 532 | m--; |
| 533 | for (i = m; 2*i+1 < n; ) |
| 534 | { |
| 535 | if (2*i+2 < n |
| 536 | && fde_compare (ob, a[2*i+2], a[2*i+1]) > 0 |
| 537 | && fde_compare (ob, a[2*i+2], a[i]) > 0) |
| 538 | { |
| 539 | SWAP (a[i], a[2*i+2]); |
| 540 | i = 2*i+2; |
| 541 | } |
| 542 | else if (fde_compare (ob, a[2*i+1], a[i]) > 0) |
| 543 | { |
| 544 | SWAP (a[i], a[2*i+1]); |
| 545 | i = 2*i+1; |
| 546 | } |
| 547 | else |
| 548 | break; |
| 549 | } |
| 550 | } |
| 551 | while (n > 1) |
| 552 | { |
| 553 | /* Invariant: a[0..n-1] is a heap. */ |
| 554 | n--; |
| 555 | SWAP (a[0], a[n]); |
| 556 | for (i = 0; 2*i+1 < n; ) |
| 557 | { |
| 558 | if (2*i+2 < n |
| 559 | && fde_compare (ob, a[2*i+2], a[2*i+1]) > 0 |
| 560 | && fde_compare (ob, a[2*i+2], a[i]) > 0) |
| 561 | { |
| 562 | SWAP (a[i], a[2*i+2]); |
| 563 | i = 2*i+2; |
| 564 | } |
| 565 | else if (fde_compare (ob, a[2*i+1], a[i]) > 0) |
| 566 | { |
| 567 | SWAP (a[i], a[2*i+1]); |
| 568 | i = 2*i+1; |
| 569 | } |
| 570 | else |
| 571 | break; |
| 572 | } |
| 573 | } |
| 574 | #undef SWAP |
| 575 | } |
| 576 | |
| 577 | /* Merge V1 and V2, both sorted, and put the result into V1. */ |
| 578 | static void |
| 579 | fde_merge (struct object *ob, fde_compare_t fde_compare, |
| 580 | struct fde_vector *v1, struct fde_vector *v2) |
| 581 | { |
| 582 | size_t i1, i2; |
| 583 | fde * fde2; |
| 584 | |
| 585 | i2 = v2->count; |
| 586 | if (i2 > 0) |
| 587 | { |
| 588 | i1 = v1->count; |
| 589 | do |
| 590 | { |
| 591 | i2--; |
| 592 | fde2 = v2->array[i2]; |
| 593 | while (i1 > 0 && fde_compare (ob, v1->array[i1-1], fde2) > 0) |
| 594 | { |
| 595 | v1->array[i1+i2] = v1->array[i1-1]; |
| 596 | i1--; |
| 597 | } |
| 598 | v1->array[i1+i2] = fde2; |
| 599 | } |
| 600 | while (i2 > 0); |
| 601 | v1->count += v2->count; |
| 602 | } |
| 603 | } |
| 604 | |
| 605 | static void |
| 606 | end_fde_sort (struct object *ob, struct fde_accumulator *accu, size_t count) |
| 607 | { |
| 608 | fde_compare_t fde_compare; |
| 609 | |
| 610 | if (accu->linear->count != count) |
| 611 | abort (); |
| 612 | |
| 613 | if (ob->s.b.mixed_encoding) |
| 614 | fde_compare = fde_mixed_encoding_compare; |
| 615 | else if (ob->s.b.encoding == DW_EH_PE_absptr) |
| 616 | fde_compare = fde_unencoded_compare; |
| 617 | else |
| 618 | fde_compare = fde_single_encoding_compare; |
| 619 | |
| 620 | if (accu->erratic) |
| 621 | { |
| 622 | fde_split (ob, fde_compare, accu->linear, accu->erratic); |
| 623 | if (accu->linear->count + accu->erratic->count != count) |
| 624 | abort (); |
| 625 | frame_heapsort (ob, fde_compare, accu->erratic); |
| 626 | fde_merge (ob, fde_compare, accu->linear, accu->erratic); |
| 627 | free (accu->erratic); |
| 628 | } |
| 629 | else |
| 630 | { |
| 631 | /* We've not managed to malloc an erratic array, |
| 632 | so heap sort in the linear one. */ |
| 633 | frame_heapsort (ob, fde_compare, accu->linear); |
| 634 | } |
| 635 | } |
| 636 | |
| 637 | |
| 638 | /* Update encoding, mixed_encoding, and pc_begin for OB for the |
| 639 | fde array beginning at THIS_FDE. Return the number of fdes |
| 640 | encountered along the way. */ |
| 641 | |
| 642 | static size_t |
| 643 | classify_object_over_fdes (struct object *ob, fde *this_fde) |
| 644 | { |
| 645 | struct dwarf_cie *last_cie = 0; |
| 646 | size_t count = 0; |
| 647 | int encoding = DW_EH_PE_absptr; |
| 648 | _Unwind_Ptr base = 0; |
| 649 | |
| 650 | for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde)) |
| 651 | { |
| 652 | struct dwarf_cie *this_cie; |
| 653 | _Unwind_Ptr mask, pc_begin; |
| 654 | |
| 655 | /* Skip CIEs. */ |
| 656 | if (this_fde->CIE_delta == 0) |
| 657 | continue; |
| 658 | |
| 659 | /* Determine the encoding for this FDE. Note mixed encoded |
| 660 | objects for later. */ |
| 661 | this_cie = get_cie (this_fde); |
| 662 | if (this_cie != last_cie) |
| 663 | { |
| 664 | last_cie = this_cie; |
| 665 | encoding = get_cie_encoding (this_cie); |
| 666 | base = base_from_object (encoding, ob); |
| 667 | if (ob->s.b.encoding == DW_EH_PE_omit) |
| 668 | ob->s.b.encoding = encoding; |
| 669 | else if (ob->s.b.encoding != encoding) |
| 670 | ob->s.b.mixed_encoding = 1; |
| 671 | } |
| 672 | |
| 673 | read_encoded_value_with_base (encoding, base, this_fde->pc_begin, |
| 674 | &pc_begin); |
| 675 | |
| 676 | /* Take care to ignore link-once functions that were removed. |
| 677 | In these cases, the function address will be NULL, but if |
| 678 | the encoding is smaller than a pointer a true NULL may not |
| 679 | be representable. Assume 0 in the representable bits is NULL. */ |
| 680 | mask = size_of_encoded_value (encoding); |
| 681 | if (mask < sizeof (void *)) |
| 682 | mask = (1L << (mask << 3)) - 1; |
| 683 | else |
| 684 | mask = -1; |
| 685 | |
| 686 | if ((pc_begin & mask) == 0) |
| 687 | continue; |
| 688 | |
| 689 | count += 1; |
| 690 | if ((void *) pc_begin < ob->pc_begin) |
| 691 | ob->pc_begin = (void *) pc_begin; |
| 692 | } |
| 693 | |
| 694 | return count; |
| 695 | } |
| 696 | |
| 697 | static void |
| 698 | add_fdes (struct object *ob, struct fde_accumulator *accu, fde *this_fde) |
| 699 | { |
| 700 | struct dwarf_cie *last_cie = 0; |
| 701 | int encoding = ob->s.b.encoding; |
| 702 | _Unwind_Ptr base = base_from_object (ob->s.b.encoding, ob); |
| 703 | |
| 704 | for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde)) |
| 705 | { |
| 706 | struct dwarf_cie *this_cie; |
| 707 | |
| 708 | /* Skip CIEs. */ |
| 709 | if (this_fde->CIE_delta == 0) |
| 710 | continue; |
| 711 | |
| 712 | if (ob->s.b.mixed_encoding) |
| 713 | { |
| 714 | /* Determine the encoding for this FDE. Note mixed encoded |
| 715 | objects for later. */ |
| 716 | this_cie = get_cie (this_fde); |
| 717 | if (this_cie != last_cie) |
| 718 | { |
| 719 | last_cie = this_cie; |
| 720 | encoding = get_cie_encoding (this_cie); |
| 721 | base = base_from_object (encoding, ob); |
| 722 | } |
| 723 | } |
| 724 | |
| 725 | if (encoding == DW_EH_PE_absptr) |
| 726 | { |
| 727 | if (get_pc_begin (this_fde, 0) == 0) |
| 728 | continue; |
| 729 | } |
| 730 | else |
| 731 | { |
| 732 | _Unwind_Ptr pc_begin, mask; |
| 733 | |
| 734 | read_encoded_value_with_base (encoding, base, this_fde->pc_begin, |
| 735 | &pc_begin); |
| 736 | |
| 737 | /* Take care to ignore link-once functions that were removed. |
| 738 | In these cases, the function address will be NULL, but if |
| 739 | the encoding is smaller than a pointer a true NULL may not |
| 740 | be representable. Assume 0 in the representable bits is NULL. */ |
| 741 | mask = size_of_encoded_value (encoding); |
| 742 | if (mask < sizeof (void *)) |
| 743 | mask = (1L << (mask << 3)) - 1; |
| 744 | else |
| 745 | mask = -1; |
| 746 | |
| 747 | if ((pc_begin & mask) == 0) |
| 748 | continue; |
| 749 | } |
| 750 | |
| 751 | fde_insert (accu, this_fde); |
| 752 | } |
| 753 | } |
| 754 | |
| 755 | /* Set up a sorted array of pointers to FDEs for a loaded object. We |
| 756 | count up the entries before allocating the array because it's likely to |
| 757 | be faster. We can be called multiple times, should we have failed to |
| 758 | allocate a sorted fde array on a previous occasion. */ |
| 759 | |
| 760 | static void |
| 761 | init_object (struct object* ob) |
| 762 | { |
| 763 | struct fde_accumulator accu; |
| 764 | size_t count; |
| 765 | |
| 766 | count = ob->s.b.count; |
| 767 | if (count == 0) |
| 768 | { |
| 769 | if (ob->s.b.from_array) |
| 770 | { |
| 771 | fde **p = ob->u.array; |
| 772 | for (count = 0; *p; ++p) |
| 773 | count += classify_object_over_fdes (ob, *p); |
| 774 | } |
| 775 | else |
| 776 | count = classify_object_over_fdes (ob, ob->u.single); |
| 777 | |
| 778 | /* The count field we have in the main struct object is somewhat |
| 779 | limited, but should suffice for virtually all cases. If the |
| 780 | counted value doesn't fit, re-write a zero. The worst that |
| 781 | happens is that we re-count next time -- admittedly non-trivial |
| 782 | in that this implies some 2M fdes, but at least we function. */ |
| 783 | ob->s.b.count = count; |
| 784 | if (ob->s.b.count != count) |
| 785 | ob->s.b.count = 0; |
| 786 | } |
| 787 | |
| 788 | if (!start_fde_sort (&accu, count)) |
| 789 | return; |
| 790 | |
| 791 | if (ob->s.b.from_array) |
| 792 | { |
| 793 | fde **p; |
| 794 | for (p = ob->u.array; *p; ++p) |
| 795 | add_fdes (ob, &accu, *p); |
| 796 | } |
| 797 | else |
| 798 | add_fdes (ob, &accu, ob->u.single); |
| 799 | |
| 800 | end_fde_sort (ob, &accu, count); |
| 801 | |
| 802 | /* Save the original fde pointer, since this is the key by which the |
| 803 | DSO will deregister the object. */ |
| 804 | accu.linear->orig_data = ob->u.single; |
| 805 | ob->u.sort = accu.linear; |
| 806 | |
| 807 | ob->s.b.sorted = 1; |
| 808 | } |
| 809 | |
| 810 | /* A linear search through a set of FDEs for the given PC. This is |
| 811 | used when there was insufficient memory to allocate and sort an |
| 812 | array. */ |
| 813 | |
| 814 | static fde * |
| 815 | linear_search_fdes (struct object *ob, fde *this_fde, void *pc) |
| 816 | { |
| 817 | struct dwarf_cie *last_cie = 0; |
| 818 | int encoding = ob->s.b.encoding; |
| 819 | _Unwind_Ptr base = base_from_object (ob->s.b.encoding, ob); |
| 820 | |
| 821 | for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde)) |
| 822 | { |
| 823 | struct dwarf_cie *this_cie; |
| 824 | _Unwind_Ptr pc_begin, pc_range; |
| 825 | |
| 826 | /* Skip CIEs. */ |
| 827 | if (this_fde->CIE_delta == 0) |
| 828 | continue; |
| 829 | |
| 830 | if (ob->s.b.mixed_encoding) |
| 831 | { |
| 832 | /* Determine the encoding for this FDE. Note mixed encoded |
| 833 | objects for later. */ |
| 834 | this_cie = get_cie (this_fde); |
| 835 | if (this_cie != last_cie) |
| 836 | { |
| 837 | last_cie = this_cie; |
| 838 | encoding = get_cie_encoding (this_cie); |
| 839 | base = base_from_object (encoding, ob); |
| 840 | } |
| 841 | } |
| 842 | |
| 843 | if (encoding == DW_EH_PE_absptr) |
| 844 | { |
| 845 | pc_begin = get_pc_begin (this_fde, 0); |
| 846 | pc_range = get_pc_begin (this_fde, 1); |
| 847 | if (pc_begin == 0) |
| 848 | continue; |
| 849 | } |
| 850 | else |
| 851 | { |
| 852 | _Unwind_Ptr mask; |
| 853 | const unsigned char *p; |
| 854 | |
| 855 | p = read_encoded_value_with_base (encoding, base, |
| 856 | this_fde->pc_begin, &pc_begin); |
| 857 | read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range); |
| 858 | |
| 859 | /* Take care to ignore link-once functions that were removed. |
| 860 | In these cases, the function address will be NULL, but if |
| 861 | the encoding is smaller than a pointer a true NULL may not |
| 862 | be representable. Assume 0 in the representable bits is NULL. */ |
| 863 | mask = size_of_encoded_value (encoding); |
| 864 | if (mask < sizeof (void *)) |
| 865 | mask = (1L << (mask << 3)) - 1; |
| 866 | else |
| 867 | mask = -1; |
| 868 | |
| 869 | if ((pc_begin & mask) == 0) |
| 870 | continue; |
| 871 | } |
| 872 | |
| 873 | if ((_Unwind_Ptr) pc - pc_begin < pc_range) |
| 874 | return this_fde; |
| 875 | } |
| 876 | |
| 877 | return NULL; |
| 878 | } |
| 879 | |
| 880 | /* Binary search for an FDE containing the given PC. Here are three |
| 881 | implementations of increasing complexity. */ |
| 882 | |
| 883 | static fde * |
| 884 | binary_search_unencoded_fdes (struct object *ob, void *pc) |
| 885 | { |
| 886 | struct fde_vector *vec = ob->u.sort; |
| 887 | size_t lo, hi; |
| 888 | |
| 889 | for (lo = 0, hi = vec->count; lo < hi; ) |
| 890 | { |
| 891 | size_t i = (lo + hi) / 2; |
| 892 | fde *f = vec->array[i]; |
| 893 | void *pc_begin; |
| 894 | uaddr pc_range; |
| 895 | |
| 896 | pc_begin = (void *) get_pc_begin (f, 0); |
| 897 | pc_range = (uaddr) get_pc_begin (f, 1); |
| 898 | |
| 899 | if (pc < pc_begin) |
| 900 | hi = i; |
| 901 | else if (pc >= pc_begin + pc_range) |
| 902 | lo = i + 1; |
| 903 | else |
| 904 | return f; |
| 905 | } |
| 906 | |
| 907 | return NULL; |
| 908 | } |
| 909 | |
| 910 | static fde * |
| 911 | binary_search_single_encoding_fdes (struct object *ob, void *pc) |
| 912 | { |
| 913 | struct fde_vector *vec = ob->u.sort; |
| 914 | int encoding = ob->s.b.encoding; |
| 915 | _Unwind_Ptr base = base_from_object (encoding, ob); |
| 916 | size_t lo, hi; |
| 917 | |
| 918 | for (lo = 0, hi = vec->count; lo < hi; ) |
| 919 | { |
| 920 | size_t i = (lo + hi) / 2; |
| 921 | fde *f = vec->array[i]; |
| 922 | _Unwind_Ptr pc_begin, pc_range; |
| 923 | const unsigned char *p; |
| 924 | |
| 925 | p = read_encoded_value_with_base (encoding, base, f->pc_begin, |
| 926 | &pc_begin); |
| 927 | read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range); |
| 928 | |
| 929 | if ((_Unwind_Ptr) pc < pc_begin) |
| 930 | hi = i; |
| 931 | else if ((_Unwind_Ptr) pc >= pc_begin + pc_range) |
| 932 | lo = i + 1; |
| 933 | else |
| 934 | return f; |
| 935 | } |
| 936 | |
| 937 | return NULL; |
| 938 | } |
| 939 | |
| 940 | static fde * |
| 941 | binary_search_mixed_encoding_fdes (struct object *ob, void *pc) |
| 942 | { |
| 943 | struct fde_vector *vec = ob->u.sort; |
| 944 | size_t lo, hi; |
| 945 | |
| 946 | for (lo = 0, hi = vec->count; lo < hi; ) |
| 947 | { |
| 948 | size_t i = (lo + hi) / 2; |
| 949 | fde *f = vec->array[i]; |
| 950 | _Unwind_Ptr pc_begin, pc_range; |
| 951 | const unsigned char *p; |
| 952 | int encoding; |
| 953 | |
| 954 | encoding = get_fde_encoding (f); |
| 955 | p = read_encoded_value_with_base (encoding, |
| 956 | base_from_object (encoding, ob), |
| 957 | f->pc_begin, &pc_begin); |
| 958 | read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range); |
| 959 | |
| 960 | if ((_Unwind_Ptr) pc < pc_begin) |
| 961 | hi = i; |
| 962 | else if ((_Unwind_Ptr) pc >= pc_begin + pc_range) |
| 963 | lo = i + 1; |
| 964 | else |
| 965 | return f; |
| 966 | } |
| 967 | |
| 968 | return NULL; |
| 969 | } |
| 970 | |
| 971 | static fde * |
| 972 | search_object (struct object* ob, void *pc) |
| 973 | { |
| 974 | /* If the data hasn't been sorted, try to do this now. We may have |
| 975 | more memory available than last time we tried. */ |
| 976 | if (! ob->s.b.sorted) |
| 977 | { |
| 978 | init_object (ob); |
| 979 | |
| 980 | /* Despite the above comment, the normal reason to get here is |
| 981 | that we've not processed this object before. A quick range |
| 982 | check is in order. */ |
| 983 | if (pc < ob->pc_begin) |
| 984 | return NULL; |
| 985 | } |
| 986 | |
| 987 | if (ob->s.b.sorted) |
| 988 | { |
| 989 | if (ob->s.b.mixed_encoding) |
| 990 | return binary_search_mixed_encoding_fdes (ob, pc); |
| 991 | else if (ob->s.b.encoding == DW_EH_PE_absptr) |
| 992 | return binary_search_unencoded_fdes (ob, pc); |
| 993 | else |
| 994 | return binary_search_single_encoding_fdes (ob, pc); |
| 995 | } |
| 996 | else |
| 997 | { |
| 998 | /* Long slow labourious linear search, cos we've no memory. */ |
| 999 | if (ob->s.b.from_array) |
| 1000 | { |
| 1001 | fde **p; |
| 1002 | for (p = ob->u.array; *p ; p++) |
| 1003 | { |
| 1004 | fde *f = linear_search_fdes (ob, *p, pc); |
| 1005 | if (f) |
| 1006 | return f; |
| 1007 | } |
| 1008 | return NULL; |
| 1009 | } |
| 1010 | else |
| 1011 | return linear_search_fdes (ob, ob->u.single, pc); |
| 1012 | } |
| 1013 | } |
| 1014 | |
| 1015 | fde * |
| 1016 | _Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases) |
| 1017 | { |
| 1018 | struct object *ob; |
| 1019 | fde *f = NULL; |
| 1020 | |
| 1021 | init_object_mutex_once (); |
| 1022 | __gthread_mutex_lock (&object_mutex); |
| 1023 | |
| 1024 | /* Linear search through the classified objects, to find the one |
| 1025 | containing the pc. Note that pc_begin is sorted descending, and |
| 1026 | we expect objects to be non-overlapping. */ |
| 1027 | for (ob = seen_objects; ob; ob = ob->next) |
| 1028 | if (pc >= ob->pc_begin) |
| 1029 | { |
| 1030 | f = search_object (ob, pc); |
| 1031 | if (f) |
| 1032 | goto fini; |
| 1033 | break; |
| 1034 | } |
| 1035 | |
| 1036 | /* Classify and search the objects we've not yet processed. */ |
| 1037 | while ((ob = unseen_objects)) |
| 1038 | { |
| 1039 | struct object **p; |
| 1040 | |
| 1041 | unseen_objects = ob->next; |
| 1042 | f = search_object (ob, pc); |
| 1043 | |
| 1044 | /* Insert the object into the classified list. */ |
| 1045 | for (p = &seen_objects; *p ; p = &(*p)->next) |
| 1046 | if ((*p)->pc_begin < ob->pc_begin) |
| 1047 | break; |
| 1048 | ob->next = *p; |
| 1049 | *p = ob; |
| 1050 | |
| 1051 | if (f) |
| 1052 | goto fini; |
| 1053 | } |
| 1054 | |
| 1055 | fini: |
| 1056 | __gthread_mutex_unlock (&object_mutex); |
| 1057 | |
| 1058 | if (f) |
| 1059 | { |
| 1060 | int encoding; |
| 1061 | _Unwind_Ptr func; |
| 1062 | |
| 1063 | bases->tbase = ob->tbase; |
| 1064 | bases->dbase = ob->dbase; |
| 1065 | |
| 1066 | encoding = ob->s.b.encoding; |
| 1067 | if (ob->s.b.mixed_encoding) |
| 1068 | encoding = get_fde_encoding (f); |
| 1069 | read_encoded_value_with_base (encoding, base_from_object (encoding, ob), |
| 1070 | f->pc_begin, &func); |
| 1071 | bases->func = (void *) func; |
| 1072 | } |
| 1073 | |
| 1074 | return f; |
| 1075 | } |
| 1076 | |
| 1077 | #endif |