| 1 | /* ldcref.c -- output a cross reference table |
| 2 | Copyright (C) 1996 Free Software Foundation, Inc. |
| 3 | Written by Ian Lance Taylor <ian@cygnus.com> |
| 4 | |
| 5 | This file is part of GLD, the Gnu Linker. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 2 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program 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 |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program; if not, write to the Free Software |
| 19 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| 20 | |
| 21 | /* This file holds routines that manage the cross reference table. |
| 22 | The table is used to generate cross reference reports. It is also |
| 23 | used to implement the NOCROSSREFS command in the linker script. */ |
| 24 | |
| 25 | #include "bfd.h" |
| 26 | #include "sysdep.h" |
| 27 | #include "bfdlink.h" |
| 28 | #include "libiberty.h" |
| 29 | |
| 30 | #include "ld.h" |
| 31 | #include "ldmain.h" |
| 32 | #include "ldmisc.h" |
| 33 | #include "ldexp.h" |
| 34 | #include "ldlang.h" |
| 35 | |
| 36 | /* We keep an instance of this structure for each reference to a |
| 37 | symbol from a given object. */ |
| 38 | |
| 39 | struct cref_ref |
| 40 | { |
| 41 | /* The next reference. */ |
| 42 | struct cref_ref *next; |
| 43 | /* The object. */ |
| 44 | bfd *abfd; |
| 45 | /* True if the symbol is defined. */ |
| 46 | unsigned int def : 1; |
| 47 | /* True if the symbol is common. */ |
| 48 | unsigned int common : 1; |
| 49 | /* True if the symbol is undefined. */ |
| 50 | unsigned int undef : 1; |
| 51 | }; |
| 52 | |
| 53 | /* We keep a hash table of symbols. Each entry looks like this. */ |
| 54 | |
| 55 | struct cref_hash_entry |
| 56 | { |
| 57 | struct bfd_hash_entry root; |
| 58 | /* The demangled name. */ |
| 59 | char *demangled; |
| 60 | /* References to and definitions of this symbol. */ |
| 61 | struct cref_ref *refs; |
| 62 | }; |
| 63 | |
| 64 | /* This is what the hash table looks like. */ |
| 65 | |
| 66 | struct cref_hash_table |
| 67 | { |
| 68 | struct bfd_hash_table root; |
| 69 | }; |
| 70 | |
| 71 | /* Local functions. */ |
| 72 | |
| 73 | static struct bfd_hash_entry *cref_hash_newfunc |
| 74 | PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *)); |
| 75 | static boolean cref_fill_array PARAMS ((struct cref_hash_entry *, PTR)); |
| 76 | static int cref_sort_array PARAMS ((const PTR, const PTR)); |
| 77 | static void output_one_cref PARAMS ((FILE *, struct cref_hash_entry *)); |
| 78 | static boolean check_nocrossref PARAMS ((struct cref_hash_entry *, PTR)); |
| 79 | static void check_refs |
| 80 | PARAMS ((struct cref_hash_entry *, struct bfd_link_hash_entry *, |
| 81 | struct lang_nocrossrefs *)); |
| 82 | static void check_reloc_refs PARAMS ((bfd *, asection *, PTR)); |
| 83 | |
| 84 | /* Look up an entry in the cref hash table. */ |
| 85 | |
| 86 | #define cref_hash_lookup(table, string, create, copy) \ |
| 87 | ((struct cref_hash_entry *) \ |
| 88 | bfd_hash_lookup (&(table)->root, (string), (create), (copy))) |
| 89 | |
| 90 | /* Traverse the cref hash table. */ |
| 91 | |
| 92 | #define cref_hash_traverse(table, func, info) \ |
| 93 | (bfd_hash_traverse \ |
| 94 | (&(table)->root, \ |
| 95 | (boolean (*) PARAMS ((struct bfd_hash_entry *, PTR))) (func), \ |
| 96 | (info))) |
| 97 | |
| 98 | /* The cref hash table. */ |
| 99 | |
| 100 | static struct cref_hash_table cref_table; |
| 101 | |
| 102 | /* Whether the cref hash table has been initialized. */ |
| 103 | |
| 104 | static boolean cref_initialized; |
| 105 | |
| 106 | /* The number of symbols seen so far. */ |
| 107 | |
| 108 | static size_t cref_symcount; |
| 109 | |
| 110 | /* Create an entry in a cref hash table. */ |
| 111 | |
| 112 | static struct bfd_hash_entry * |
| 113 | cref_hash_newfunc (entry, table, string) |
| 114 | struct bfd_hash_entry *entry; |
| 115 | struct bfd_hash_table *table; |
| 116 | const char *string; |
| 117 | { |
| 118 | struct cref_hash_entry *ret = (struct cref_hash_entry *) entry; |
| 119 | |
| 120 | /* Allocate the structure if it has not already been allocated by a |
| 121 | subclass. */ |
| 122 | if (ret == NULL) |
| 123 | ret = ((struct cref_hash_entry *) |
| 124 | bfd_hash_allocate (table, sizeof (struct cref_hash_entry))); |
| 125 | if (ret == NULL) |
| 126 | return (struct bfd_hash_entry *) ret; |
| 127 | |
| 128 | /* Call the allocation method of the superclass. */ |
| 129 | ret = ((struct cref_hash_entry *) |
| 130 | bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string)); |
| 131 | if (ret != NULL) |
| 132 | { |
| 133 | /* Set local fields. */ |
| 134 | ret->demangled = NULL; |
| 135 | ret->refs = NULL; |
| 136 | |
| 137 | /* Keep a count of the number of entries created in the hash |
| 138 | table. */ |
| 139 | ++cref_symcount; |
| 140 | } |
| 141 | |
| 142 | return (struct bfd_hash_entry *) ret; |
| 143 | } |
| 144 | |
| 145 | /* Add a symbol to the cref hash table. This is called for every |
| 146 | symbol that is seen during the link. */ |
| 147 | |
| 148 | /*ARGSUSED*/ |
| 149 | void |
| 150 | add_cref (name, abfd, section, value) |
| 151 | const char *name; |
| 152 | bfd *abfd; |
| 153 | asection *section; |
| 154 | bfd_vma value; |
| 155 | { |
| 156 | struct cref_hash_entry *h; |
| 157 | struct cref_ref *r; |
| 158 | |
| 159 | if (! cref_initialized) |
| 160 | { |
| 161 | if (! bfd_hash_table_init (&cref_table.root, cref_hash_newfunc)) |
| 162 | einfo ("%X%P: bfd_hash_table_init of cref table failed: %E\n"); |
| 163 | cref_initialized = true; |
| 164 | } |
| 165 | |
| 166 | h = cref_hash_lookup (&cref_table, name, true, false); |
| 167 | if (h == NULL) |
| 168 | einfo ("%X%P: cref_hash_lookup failed: %E\n"); |
| 169 | |
| 170 | for (r = h->refs; r != NULL; r = r->next) |
| 171 | if (r->abfd == abfd) |
| 172 | break; |
| 173 | |
| 174 | if (r == NULL) |
| 175 | { |
| 176 | r = (struct cref_ref *) xmalloc (sizeof *r); |
| 177 | r->next = h->refs; |
| 178 | h->refs = r; |
| 179 | r->abfd = abfd; |
| 180 | r->def = false; |
| 181 | r->common = false; |
| 182 | r->undef = false; |
| 183 | } |
| 184 | |
| 185 | if (bfd_is_und_section (section)) |
| 186 | r->undef = true; |
| 187 | else if (bfd_is_com_section (section)) |
| 188 | r->common = true; |
| 189 | else |
| 190 | r->def = true; |
| 191 | } |
| 192 | |
| 193 | /* Copy the addresses of the hash table entries into an array. This |
| 194 | is called via cref_hash_traverse. We also fill in the demangled |
| 195 | name. */ |
| 196 | |
| 197 | static boolean |
| 198 | cref_fill_array (h, data) |
| 199 | struct cref_hash_entry *h; |
| 200 | PTR data; |
| 201 | { |
| 202 | struct cref_hash_entry ***pph = (struct cref_hash_entry ***) data; |
| 203 | |
| 204 | ASSERT (h->demangled == NULL); |
| 205 | h->demangled = demangle (h->root.string); |
| 206 | |
| 207 | **pph = h; |
| 208 | |
| 209 | ++*pph; |
| 210 | |
| 211 | return true; |
| 212 | } |
| 213 | |
| 214 | /* Sort an array of cref hash table entries by name. */ |
| 215 | |
| 216 | static int |
| 217 | cref_sort_array (a1, a2) |
| 218 | const PTR a1; |
| 219 | const PTR a2; |
| 220 | { |
| 221 | const struct cref_hash_entry **p1 = (const struct cref_hash_entry **) a1; |
| 222 | const struct cref_hash_entry **p2 = (const struct cref_hash_entry **) a2; |
| 223 | |
| 224 | return strcmp ((*p1)->demangled, (*p2)->demangled); |
| 225 | } |
| 226 | |
| 227 | /* Write out the cref table. */ |
| 228 | |
| 229 | #define FILECOL (50) |
| 230 | |
| 231 | void |
| 232 | output_cref (fp) |
| 233 | FILE *fp; |
| 234 | { |
| 235 | int len; |
| 236 | struct cref_hash_entry **csyms, **csym_fill, **csym, **csym_end; |
| 237 | |
| 238 | fprintf (fp, "\nCross Reference Table\n\n"); |
| 239 | fprintf (fp, "Symbol"); |
| 240 | len = sizeof "Symbol" - 1; |
| 241 | while (len < FILECOL) |
| 242 | { |
| 243 | putc (' ' , fp); |
| 244 | ++len; |
| 245 | } |
| 246 | fprintf (fp, "File\n"); |
| 247 | |
| 248 | if (! cref_initialized) |
| 249 | { |
| 250 | fprintf (fp, "No symbols\n"); |
| 251 | return; |
| 252 | } |
| 253 | |
| 254 | csyms = ((struct cref_hash_entry **) |
| 255 | xmalloc (cref_symcount * sizeof (*csyms))); |
| 256 | |
| 257 | csym_fill = csyms; |
| 258 | cref_hash_traverse (&cref_table, cref_fill_array, &csym_fill); |
| 259 | ASSERT (csym_fill - csyms == cref_symcount); |
| 260 | |
| 261 | qsort (csyms, cref_symcount, sizeof (*csyms), cref_sort_array); |
| 262 | |
| 263 | csym_end = csyms + cref_symcount; |
| 264 | for (csym = csyms; csym < csym_end; csym++) |
| 265 | output_one_cref (fp, *csym); |
| 266 | } |
| 267 | |
| 268 | /* Output one entry in the cross reference table. */ |
| 269 | |
| 270 | static void |
| 271 | output_one_cref (fp, h) |
| 272 | FILE *fp; |
| 273 | struct cref_hash_entry *h; |
| 274 | { |
| 275 | int len; |
| 276 | struct bfd_link_hash_entry *hl; |
| 277 | struct cref_ref *r; |
| 278 | |
| 279 | hl = bfd_link_hash_lookup (link_info.hash, h->root.string, false, |
| 280 | false, true); |
| 281 | if (hl == NULL) |
| 282 | einfo ("%P: symbol `%T' missing from main hash table\n", |
| 283 | h->root.string); |
| 284 | else |
| 285 | { |
| 286 | /* If this symbol is defined in a dynamic object but never |
| 287 | referenced by a normal object, then don't print it. */ |
| 288 | if (hl->type == bfd_link_hash_defined) |
| 289 | { |
| 290 | if (hl->u.def.section->output_section == NULL) |
| 291 | return; |
| 292 | if (hl->u.def.section->owner != NULL |
| 293 | && (hl->u.def.section->owner->flags & DYNAMIC) != 0) |
| 294 | { |
| 295 | for (r = h->refs; r != NULL; r = r->next) |
| 296 | if ((r->abfd->flags & DYNAMIC) == 0) |
| 297 | break; |
| 298 | if (r == NULL) |
| 299 | return; |
| 300 | } |
| 301 | } |
| 302 | } |
| 303 | |
| 304 | fprintf (fp, "%s ", h->demangled); |
| 305 | len = strlen (h->demangled) + 1; |
| 306 | |
| 307 | for (r = h->refs; r != NULL; r = r->next) |
| 308 | { |
| 309 | if (r->def) |
| 310 | { |
| 311 | while (len < FILECOL) |
| 312 | { |
| 313 | putc (' ', fp); |
| 314 | ++len; |
| 315 | } |
| 316 | finfo (fp, "%B\n", r->abfd); |
| 317 | len = 0; |
| 318 | } |
| 319 | } |
| 320 | |
| 321 | for (r = h->refs; r != NULL; r = r->next) |
| 322 | { |
| 323 | if (! r->def) |
| 324 | { |
| 325 | while (len < FILECOL) |
| 326 | { |
| 327 | putc (' ', fp); |
| 328 | ++len; |
| 329 | } |
| 330 | finfo (fp, "%B\n", r->abfd); |
| 331 | len = 0; |
| 332 | } |
| 333 | } |
| 334 | |
| 335 | ASSERT (len == 0); |
| 336 | } |
| 337 | |
| 338 | /* Check for prohibited cross references. */ |
| 339 | |
| 340 | void |
| 341 | check_nocrossrefs () |
| 342 | { |
| 343 | if (! cref_initialized) |
| 344 | return; |
| 345 | |
| 346 | cref_hash_traverse (&cref_table, check_nocrossref, (PTR) NULL); |
| 347 | } |
| 348 | |
| 349 | /* Check one symbol to see if it is a prohibited cross reference. */ |
| 350 | |
| 351 | /*ARGSUSED*/ |
| 352 | static boolean |
| 353 | check_nocrossref (h, ignore) |
| 354 | struct cref_hash_entry *h; |
| 355 | PTR ignore; |
| 356 | { |
| 357 | struct bfd_link_hash_entry *hl; |
| 358 | asection *defsec; |
| 359 | const char *defsecname; |
| 360 | struct lang_nocrossrefs *ncrs; |
| 361 | struct lang_nocrossref *ncr; |
| 362 | |
| 363 | hl = bfd_link_hash_lookup (link_info.hash, h->root.string, false, |
| 364 | false, true); |
| 365 | if (hl == NULL) |
| 366 | { |
| 367 | einfo ("%P: symbol `%T' missing from main hash table\n", |
| 368 | h->root.string); |
| 369 | return true; |
| 370 | } |
| 371 | |
| 372 | if (hl->type != bfd_link_hash_defined |
| 373 | && hl->type != bfd_link_hash_defweak) |
| 374 | return true; |
| 375 | |
| 376 | defsec = hl->u.def.section->output_section; |
| 377 | if (defsec == NULL) |
| 378 | return true; |
| 379 | defsecname = bfd_get_section_name (defsec->owner, defsec); |
| 380 | |
| 381 | for (ncrs = nocrossref_list; ncrs != NULL; ncrs = ncrs->next) |
| 382 | for (ncr = ncrs->list; ncr != NULL; ncr = ncr->next) |
| 383 | if (strcmp (ncr->name, defsecname) == 0) |
| 384 | check_refs (h, hl, ncrs); |
| 385 | |
| 386 | return true; |
| 387 | } |
| 388 | |
| 389 | /* The struct is used to pass information from check_refs to |
| 390 | check_reloc_refs through bfd_map_over_sections. */ |
| 391 | |
| 392 | struct check_refs_info |
| 393 | { |
| 394 | struct cref_hash_entry *h; |
| 395 | asection *defsec; |
| 396 | struct lang_nocrossrefs *ncrs; |
| 397 | asymbol **asymbols; |
| 398 | boolean same; |
| 399 | }; |
| 400 | |
| 401 | /* This function is called for each symbol defined in a section which |
| 402 | prohibits cross references. We need to look through all references |
| 403 | to this symbol, and ensure that the references are not from |
| 404 | prohibited sections. */ |
| 405 | |
| 406 | static void |
| 407 | check_refs (h, hl, ncrs) |
| 408 | struct cref_hash_entry *h; |
| 409 | struct bfd_link_hash_entry *hl; |
| 410 | struct lang_nocrossrefs *ncrs; |
| 411 | { |
| 412 | struct cref_ref *ref; |
| 413 | |
| 414 | for (ref = h->refs; ref != NULL; ref = ref->next) |
| 415 | { |
| 416 | lang_input_statement_type *li; |
| 417 | asymbol **asymbols; |
| 418 | struct check_refs_info info; |
| 419 | |
| 420 | /* We need to look through the relocations for this BFD, to see |
| 421 | if any of the relocations which refer to this symbol are from |
| 422 | a prohibited section. Note that we need to do this even for |
| 423 | the BFD in which the symbol is defined, since even a single |
| 424 | BFD might contain a prohibited cross reference; for this |
| 425 | case, we set the SAME field in INFO, which will cause |
| 426 | CHECK_RELOCS_REFS to check for relocations against the |
| 427 | section as well as against the symbol. */ |
| 428 | |
| 429 | li = (lang_input_statement_type *) ref->abfd->usrdata; |
| 430 | if (li != NULL && li->asymbols != NULL) |
| 431 | asymbols = li->asymbols; |
| 432 | else |
| 433 | { |
| 434 | long symsize; |
| 435 | long symbol_count; |
| 436 | |
| 437 | symsize = bfd_get_symtab_upper_bound (ref->abfd); |
| 438 | if (symsize < 0) |
| 439 | einfo ("%B%F: could not read symbols; %E\n", ref->abfd); |
| 440 | asymbols = (asymbol **) xmalloc (symsize); |
| 441 | symbol_count = bfd_canonicalize_symtab (ref->abfd, asymbols); |
| 442 | if (symbol_count < 0) |
| 443 | einfo ("%B%F: could not read symbols: %E\n", ref->abfd); |
| 444 | if (li != NULL) |
| 445 | { |
| 446 | li->asymbols = asymbols; |
| 447 | li->symbol_count = symbol_count; |
| 448 | } |
| 449 | } |
| 450 | |
| 451 | info.h = h; |
| 452 | info.defsec = hl->u.def.section; |
| 453 | info.ncrs = ncrs; |
| 454 | info.asymbols = asymbols; |
| 455 | if (ref->abfd == hl->u.def.section->owner) |
| 456 | info.same = true; |
| 457 | else |
| 458 | info.same = false; |
| 459 | bfd_map_over_sections (ref->abfd, check_reloc_refs, (PTR) &info); |
| 460 | |
| 461 | if (li == NULL) |
| 462 | free (asymbols); |
| 463 | } |
| 464 | } |
| 465 | |
| 466 | /* This is called via bfd_map_over_sections. INFO->H is a symbol |
| 467 | defined in INFO->DEFSECNAME. If this section maps into any of the |
| 468 | sections listed in INFO->NCRS, other than INFO->DEFSECNAME, then we |
| 469 | look through the relocations. If any of the relocations are to |
| 470 | INFO->H, then we report a prohibited cross reference error. */ |
| 471 | |
| 472 | static void |
| 473 | check_reloc_refs (abfd, sec, iarg) |
| 474 | bfd *abfd; |
| 475 | asection *sec; |
| 476 | PTR iarg; |
| 477 | { |
| 478 | struct check_refs_info *info = (struct check_refs_info *) iarg; |
| 479 | asection *outsec; |
| 480 | const char *outsecname; |
| 481 | asection *outdefsec; |
| 482 | const char *outdefsecname; |
| 483 | struct lang_nocrossref *ncr; |
| 484 | const char *symname; |
| 485 | long relsize; |
| 486 | arelent **relpp; |
| 487 | long relcount; |
| 488 | arelent **p, **pend; |
| 489 | |
| 490 | outsec = sec->output_section; |
| 491 | outsecname = bfd_get_section_name (outsec->owner, outsec); |
| 492 | |
| 493 | outdefsec = info->defsec->output_section; |
| 494 | outdefsecname = bfd_get_section_name (outdefsec->owner, outdefsec); |
| 495 | |
| 496 | /* The section where the symbol is defined is permitted. */ |
| 497 | if (strcmp (outsecname, outdefsecname) == 0) |
| 498 | return; |
| 499 | |
| 500 | for (ncr = info->ncrs->list; ncr != NULL; ncr = ncr->next) |
| 501 | if (strcmp (outsecname, ncr->name) == 0) |
| 502 | break; |
| 503 | |
| 504 | if (ncr == NULL) |
| 505 | return; |
| 506 | |
| 507 | /* This section is one for which cross references are prohibited. |
| 508 | Look through the relocations, and see if any of them are to |
| 509 | INFO->H. */ |
| 510 | |
| 511 | symname = info->h->root.string; |
| 512 | |
| 513 | relsize = bfd_get_reloc_upper_bound (abfd, sec); |
| 514 | if (relsize < 0) |
| 515 | einfo ("%B%F: could not read relocs: %E\n", abfd); |
| 516 | if (relsize == 0) |
| 517 | return; |
| 518 | |
| 519 | relpp = (arelent **) xmalloc (relsize); |
| 520 | relcount = bfd_canonicalize_reloc (abfd, sec, relpp, info->asymbols); |
| 521 | if (relcount < 0) |
| 522 | einfo ("%B%F: could not read relocs: %E\n", abfd); |
| 523 | |
| 524 | p = relpp; |
| 525 | pend = p + relcount; |
| 526 | for (; p < pend && *p != NULL; p++) |
| 527 | { |
| 528 | arelent *q = *p; |
| 529 | |
| 530 | if (q->sym_ptr_ptr != NULL |
| 531 | && *q->sym_ptr_ptr != NULL |
| 532 | && (strcmp (bfd_asymbol_name (*q->sym_ptr_ptr), symname) == 0 |
| 533 | || (info->same |
| 534 | && *q->sym_ptr_ptr == info->defsec->symbol))) |
| 535 | { |
| 536 | /* We found a reloc for the symbol. The symbol is defined |
| 537 | in OUTSECNAME. This reloc is from a section which is |
| 538 | mapped into a section from which references to OUTSECNAME |
| 539 | are prohibited. We must report an error. */ |
| 540 | einfo ("%X%C: prohibited cross reference from %s to `%T' in %s\n", |
| 541 | abfd, sec, q->address, outsecname, |
| 542 | bfd_asymbol_name (*q->sym_ptr_ptr), outdefsecname); |
| 543 | } |
| 544 | } |
| 545 | |
| 546 | free (relpp); |
| 547 | } |