| 1 | /* ldwrite.c -- write out the linked file |
| 2 | Copyright (C) 1991-2016 Free Software Foundation, Inc. |
| 3 | Written by Steve Chamberlain sac@cygnus.com |
| 4 | |
| 5 | This file is part of the GNU Binutils. |
| 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 3 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., 51 Franklin Street - Fifth Floor, Boston, |
| 20 | MA 02110-1301, USA. */ |
| 21 | |
| 22 | #include "sysdep.h" |
| 23 | #include "bfd.h" |
| 24 | #include "bfdlink.h" |
| 25 | #include "libiberty.h" |
| 26 | #include "safe-ctype.h" |
| 27 | |
| 28 | #include "ld.h" |
| 29 | #include "ldexp.h" |
| 30 | #include "ldlang.h" |
| 31 | #include "ldwrite.h" |
| 32 | #include "ldmisc.h" |
| 33 | #include <ldgram.h> |
| 34 | #include "ldmain.h" |
| 35 | |
| 36 | /* Build link_order structures for the BFD linker. */ |
| 37 | |
| 38 | static void |
| 39 | build_link_order (lang_statement_union_type *statement) |
| 40 | { |
| 41 | switch (statement->header.type) |
| 42 | { |
| 43 | case lang_data_statement_enum: |
| 44 | { |
| 45 | asection *output_section; |
| 46 | struct bfd_link_order *link_order; |
| 47 | bfd_vma value; |
| 48 | bfd_boolean big_endian = FALSE; |
| 49 | |
| 50 | output_section = statement->data_statement.output_section; |
| 51 | ASSERT (output_section->owner == link_info.output_bfd); |
| 52 | |
| 53 | if (!((output_section->flags & SEC_HAS_CONTENTS) != 0 |
| 54 | || ((output_section->flags & SEC_LOAD) != 0 |
| 55 | && (output_section->flags & SEC_THREAD_LOCAL)))) |
| 56 | break; |
| 57 | |
| 58 | link_order = bfd_new_link_order (link_info.output_bfd, output_section); |
| 59 | if (link_order == NULL) |
| 60 | einfo (_("%P%F: bfd_new_link_order failed\n")); |
| 61 | |
| 62 | link_order->type = bfd_data_link_order; |
| 63 | link_order->offset = statement->data_statement.output_offset; |
| 64 | link_order->u.data.contents = (bfd_byte *) xmalloc (QUAD_SIZE); |
| 65 | |
| 66 | value = statement->data_statement.value; |
| 67 | |
| 68 | /* If the endianness of the output BFD is not known, then we |
| 69 | base the endianness of the data on the first input file. |
| 70 | By convention, the bfd_put routines for an unknown |
| 71 | endianness are big endian, so we must swap here if the |
| 72 | input file is little endian. */ |
| 73 | if (bfd_big_endian (link_info.output_bfd)) |
| 74 | big_endian = TRUE; |
| 75 | else if (bfd_little_endian (link_info.output_bfd)) |
| 76 | big_endian = FALSE; |
| 77 | else |
| 78 | { |
| 79 | bfd_boolean swap; |
| 80 | |
| 81 | swap = FALSE; |
| 82 | if (command_line.endian == ENDIAN_BIG) |
| 83 | big_endian = TRUE; |
| 84 | else if (command_line.endian == ENDIAN_LITTLE) |
| 85 | { |
| 86 | big_endian = FALSE; |
| 87 | swap = TRUE; |
| 88 | } |
| 89 | else if (command_line.endian == ENDIAN_UNSET) |
| 90 | { |
| 91 | big_endian = TRUE; |
| 92 | { |
| 93 | LANG_FOR_EACH_INPUT_STATEMENT (s) |
| 94 | { |
| 95 | if (s->the_bfd != NULL) |
| 96 | { |
| 97 | if (bfd_little_endian (s->the_bfd)) |
| 98 | { |
| 99 | big_endian = FALSE; |
| 100 | swap = TRUE; |
| 101 | } |
| 102 | break; |
| 103 | } |
| 104 | } |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | if (swap) |
| 109 | { |
| 110 | bfd_byte buffer[8]; |
| 111 | |
| 112 | switch (statement->data_statement.type) |
| 113 | { |
| 114 | case QUAD: |
| 115 | case SQUAD: |
| 116 | if (sizeof (bfd_vma) >= QUAD_SIZE) |
| 117 | { |
| 118 | bfd_putl64 (value, buffer); |
| 119 | value = bfd_getb64 (buffer); |
| 120 | break; |
| 121 | } |
| 122 | /* Fall through. */ |
| 123 | case LONG: |
| 124 | bfd_putl32 (value, buffer); |
| 125 | value = bfd_getb32 (buffer); |
| 126 | break; |
| 127 | case SHORT: |
| 128 | bfd_putl16 (value, buffer); |
| 129 | value = bfd_getb16 (buffer); |
| 130 | break; |
| 131 | case BYTE: |
| 132 | break; |
| 133 | default: |
| 134 | abort (); |
| 135 | } |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | ASSERT (output_section->owner == link_info.output_bfd); |
| 140 | switch (statement->data_statement.type) |
| 141 | { |
| 142 | case QUAD: |
| 143 | case SQUAD: |
| 144 | if (sizeof (bfd_vma) >= QUAD_SIZE) |
| 145 | bfd_put_64 (link_info.output_bfd, value, |
| 146 | link_order->u.data.contents); |
| 147 | else |
| 148 | { |
| 149 | bfd_vma high; |
| 150 | |
| 151 | if (statement->data_statement.type == QUAD) |
| 152 | high = 0; |
| 153 | else if ((value & 0x80000000) == 0) |
| 154 | high = 0; |
| 155 | else |
| 156 | high = (bfd_vma) -1; |
| 157 | bfd_put_32 (link_info.output_bfd, high, |
| 158 | (link_order->u.data.contents |
| 159 | + (big_endian ? 0 : 4))); |
| 160 | bfd_put_32 (link_info.output_bfd, value, |
| 161 | (link_order->u.data.contents |
| 162 | + (big_endian ? 4 : 0))); |
| 163 | } |
| 164 | link_order->size = QUAD_SIZE; |
| 165 | break; |
| 166 | case LONG: |
| 167 | bfd_put_32 (link_info.output_bfd, value, |
| 168 | link_order->u.data.contents); |
| 169 | link_order->size = LONG_SIZE; |
| 170 | break; |
| 171 | case SHORT: |
| 172 | bfd_put_16 (link_info.output_bfd, value, |
| 173 | link_order->u.data.contents); |
| 174 | link_order->size = SHORT_SIZE; |
| 175 | break; |
| 176 | case BYTE: |
| 177 | bfd_put_8 (link_info.output_bfd, value, |
| 178 | link_order->u.data.contents); |
| 179 | link_order->size = BYTE_SIZE; |
| 180 | break; |
| 181 | default: |
| 182 | abort (); |
| 183 | } |
| 184 | link_order->u.data.size = link_order->size; |
| 185 | } |
| 186 | break; |
| 187 | |
| 188 | case lang_reloc_statement_enum: |
| 189 | { |
| 190 | lang_reloc_statement_type *rs; |
| 191 | asection *output_section; |
| 192 | struct bfd_link_order *link_order; |
| 193 | |
| 194 | rs = &statement->reloc_statement; |
| 195 | |
| 196 | output_section = rs->output_section; |
| 197 | ASSERT (output_section->owner == link_info.output_bfd); |
| 198 | |
| 199 | if (!((output_section->flags & SEC_HAS_CONTENTS) != 0 |
| 200 | || ((output_section->flags & SEC_LOAD) != 0 |
| 201 | && (output_section->flags & SEC_THREAD_LOCAL)))) |
| 202 | break; |
| 203 | |
| 204 | link_order = bfd_new_link_order (link_info.output_bfd, output_section); |
| 205 | if (link_order == NULL) |
| 206 | einfo (_("%P%F: bfd_new_link_order failed\n")); |
| 207 | |
| 208 | link_order->offset = rs->output_offset; |
| 209 | link_order->size = bfd_get_reloc_size (rs->howto); |
| 210 | |
| 211 | link_order->u.reloc.p = (struct bfd_link_order_reloc *) |
| 212 | xmalloc (sizeof (struct bfd_link_order_reloc)); |
| 213 | |
| 214 | link_order->u.reloc.p->reloc = rs->reloc; |
| 215 | link_order->u.reloc.p->addend = rs->addend_value; |
| 216 | |
| 217 | if (rs->name == NULL) |
| 218 | { |
| 219 | link_order->type = bfd_section_reloc_link_order; |
| 220 | if (rs->section->owner == link_info.output_bfd) |
| 221 | link_order->u.reloc.p->u.section = rs->section; |
| 222 | else |
| 223 | { |
| 224 | link_order->u.reloc.p->u.section = rs->section->output_section; |
| 225 | link_order->u.reloc.p->addend += rs->section->output_offset; |
| 226 | } |
| 227 | } |
| 228 | else |
| 229 | { |
| 230 | link_order->type = bfd_symbol_reloc_link_order; |
| 231 | link_order->u.reloc.p->u.name = rs->name; |
| 232 | } |
| 233 | } |
| 234 | break; |
| 235 | |
| 236 | case lang_input_section_enum: |
| 237 | { |
| 238 | /* Create a new link_order in the output section with this |
| 239 | attached */ |
| 240 | asection *i = statement->input_section.section; |
| 241 | |
| 242 | if (i->sec_info_type != SEC_INFO_TYPE_JUST_SYMS |
| 243 | && (i->flags & SEC_EXCLUDE) == 0) |
| 244 | { |
| 245 | asection *output_section = i->output_section; |
| 246 | struct bfd_link_order *link_order; |
| 247 | |
| 248 | ASSERT (output_section->owner == link_info.output_bfd); |
| 249 | |
| 250 | if (!((output_section->flags & SEC_HAS_CONTENTS) != 0 |
| 251 | || ((output_section->flags & SEC_LOAD) != 0 |
| 252 | && (output_section->flags & SEC_THREAD_LOCAL)))) |
| 253 | break; |
| 254 | |
| 255 | link_order = bfd_new_link_order (link_info.output_bfd, |
| 256 | output_section); |
| 257 | |
| 258 | if ((i->flags & SEC_NEVER_LOAD) != 0 |
| 259 | && (i->flags & SEC_DEBUGGING) == 0) |
| 260 | { |
| 261 | /* We've got a never load section inside one which is |
| 262 | going to be output, we'll change it into a fill. */ |
| 263 | link_order->type = bfd_data_link_order; |
| 264 | link_order->u.data.contents = (unsigned char *) ""; |
| 265 | link_order->u.data.size = 1; |
| 266 | } |
| 267 | else |
| 268 | { |
| 269 | link_order->type = bfd_indirect_link_order; |
| 270 | link_order->u.indirect.section = i; |
| 271 | ASSERT (i->output_section == output_section); |
| 272 | } |
| 273 | link_order->size = i->size; |
| 274 | link_order->offset = i->output_offset; |
| 275 | } |
| 276 | } |
| 277 | break; |
| 278 | |
| 279 | case lang_padding_statement_enum: |
| 280 | /* Make a new link_order with the right filler */ |
| 281 | { |
| 282 | asection *output_section; |
| 283 | struct bfd_link_order *link_order; |
| 284 | |
| 285 | output_section = statement->padding_statement.output_section; |
| 286 | ASSERT (statement->padding_statement.output_section->owner |
| 287 | == link_info.output_bfd); |
| 288 | |
| 289 | if (!((output_section->flags & SEC_HAS_CONTENTS) != 0 |
| 290 | || ((output_section->flags & SEC_LOAD) != 0 |
| 291 | && (output_section->flags & SEC_THREAD_LOCAL)))) |
| 292 | break; |
| 293 | |
| 294 | link_order = bfd_new_link_order (link_info.output_bfd, |
| 295 | output_section); |
| 296 | link_order->type = bfd_data_link_order; |
| 297 | link_order->size = statement->padding_statement.size; |
| 298 | link_order->offset = statement->padding_statement.output_offset; |
| 299 | link_order->u.data.contents = statement->padding_statement.fill->data; |
| 300 | link_order->u.data.size = statement->padding_statement.fill->size; |
| 301 | } |
| 302 | break; |
| 303 | |
| 304 | default: |
| 305 | /* All the other ones fall through */ |
| 306 | break; |
| 307 | } |
| 308 | } |
| 309 | |
| 310 | /* Return true if NAME is the name of an unsplittable section. These |
| 311 | are the stabs strings, dwarf strings. */ |
| 312 | |
| 313 | static bfd_boolean |
| 314 | unsplittable_name (const char *name) |
| 315 | { |
| 316 | if (CONST_STRNEQ (name, ".stab")) |
| 317 | { |
| 318 | /* There are several stab like string sections. We pattern match on |
| 319 | ".stab...str" */ |
| 320 | unsigned len = strlen (name); |
| 321 | if (strcmp (&name[len-3], "str") == 0) |
| 322 | return TRUE; |
| 323 | } |
| 324 | else if (strcmp (name, "$GDB_STRINGS$") == 0) |
| 325 | return TRUE; |
| 326 | return FALSE; |
| 327 | } |
| 328 | |
| 329 | /* Wander around the input sections, make sure that |
| 330 | we'll never try and create an output section with more relocs |
| 331 | than will fit.. Do this by always assuming the worst case, and |
| 332 | creating new output sections with all the right bits. */ |
| 333 | #define TESTIT 1 |
| 334 | static asection * |
| 335 | clone_section (bfd *abfd, asection *s, const char *name, int *count) |
| 336 | { |
| 337 | char *tname; |
| 338 | char *sname; |
| 339 | unsigned int len; |
| 340 | asection *n; |
| 341 | struct bfd_link_hash_entry *h; |
| 342 | |
| 343 | /* Invent a section name from the section name and a dotted numeric |
| 344 | suffix. */ |
| 345 | len = strlen (name); |
| 346 | tname = (char *) xmalloc (len + 1); |
| 347 | memcpy (tname, name, len + 1); |
| 348 | /* Remove a dotted number suffix, from a previous split link. */ |
| 349 | while (len && ISDIGIT (tname[len-1])) |
| 350 | len--; |
| 351 | if (len > 1 && tname[len-1] == '.') |
| 352 | /* It was a dotted number. */ |
| 353 | tname[len-1] = 0; |
| 354 | |
| 355 | /* We want to use the whole of the original section name for the |
| 356 | split name, but coff can be restricted to 8 character names. */ |
| 357 | if (bfd_family_coff (abfd) && strlen (tname) > 5) |
| 358 | { |
| 359 | /* Some section names cannot be truncated, as the name is |
| 360 | used to locate some other section. */ |
| 361 | if (CONST_STRNEQ (name, ".stab") |
| 362 | || strcmp (name, "$GDB_SYMBOLS$") == 0) |
| 363 | { |
| 364 | einfo (_ ("%F%P: cannot create split section name for %s\n"), name); |
| 365 | /* Silence gcc warnings. einfo exits, so we never reach here. */ |
| 366 | return NULL; |
| 367 | } |
| 368 | tname[5] = 0; |
| 369 | } |
| 370 | |
| 371 | if ((sname = bfd_get_unique_section_name (abfd, tname, count)) == NULL |
| 372 | || (n = bfd_make_section_anyway (abfd, sname)) == NULL |
| 373 | || (h = bfd_link_hash_lookup (link_info.hash, |
| 374 | sname, TRUE, TRUE, FALSE)) == NULL) |
| 375 | { |
| 376 | einfo (_("%F%P: clone section failed: %E\n")); |
| 377 | /* Silence gcc warnings. einfo exits, so we never reach here. */ |
| 378 | return NULL; |
| 379 | } |
| 380 | free (tname); |
| 381 | |
| 382 | /* Set up section symbol. */ |
| 383 | h->type = bfd_link_hash_defined; |
| 384 | h->u.def.value = 0; |
| 385 | h->u.def.section = n; |
| 386 | |
| 387 | n->flags = s->flags; |
| 388 | n->vma = s->vma; |
| 389 | n->user_set_vma = s->user_set_vma; |
| 390 | n->lma = s->lma; |
| 391 | n->size = 0; |
| 392 | n->output_offset = s->output_offset; |
| 393 | n->output_section = n; |
| 394 | n->orelocation = 0; |
| 395 | n->reloc_count = 0; |
| 396 | n->alignment_power = s->alignment_power; |
| 397 | |
| 398 | bfd_copy_private_section_data (abfd, s, abfd, n); |
| 399 | |
| 400 | return n; |
| 401 | } |
| 402 | |
| 403 | #if TESTING |
| 404 | static void |
| 405 | ds (asection *s) |
| 406 | { |
| 407 | struct bfd_link_order *l = s->map_head.link_order; |
| 408 | printf ("vma %x size %x\n", s->vma, s->size); |
| 409 | while (l) |
| 410 | { |
| 411 | if (l->type == bfd_indirect_link_order) |
| 412 | { |
| 413 | printf ("%8x %s\n", l->offset, l->u.indirect.section->owner->filename); |
| 414 | } |
| 415 | else |
| 416 | { |
| 417 | printf (_("%8x something else\n"), l->offset); |
| 418 | } |
| 419 | l = l->next; |
| 420 | } |
| 421 | printf ("\n"); |
| 422 | } |
| 423 | |
| 424 | dump (char *s, asection *a1, asection *a2) |
| 425 | { |
| 426 | printf ("%s\n", s); |
| 427 | ds (a1); |
| 428 | ds (a2); |
| 429 | } |
| 430 | |
| 431 | static void |
| 432 | sanity_check (bfd *abfd) |
| 433 | { |
| 434 | asection *s; |
| 435 | for (s = abfd->sections; s; s = s->next) |
| 436 | { |
| 437 | struct bfd_link_order *p; |
| 438 | bfd_vma prev = 0; |
| 439 | for (p = s->map_head.link_order; p; p = p->next) |
| 440 | { |
| 441 | if (p->offset > 100000) |
| 442 | abort (); |
| 443 | if (p->offset < prev) |
| 444 | abort (); |
| 445 | prev = p->offset; |
| 446 | } |
| 447 | } |
| 448 | } |
| 449 | #else |
| 450 | #define sanity_check(a) |
| 451 | #define dump(a, b, c) |
| 452 | #endif |
| 453 | |
| 454 | static void |
| 455 | split_sections (bfd *abfd, struct bfd_link_info *info) |
| 456 | { |
| 457 | asection *original_sec; |
| 458 | int nsecs = abfd->section_count; |
| 459 | sanity_check (abfd); |
| 460 | /* Look through all the original sections. */ |
| 461 | for (original_sec = abfd->sections; |
| 462 | original_sec && nsecs; |
| 463 | original_sec = original_sec->next, nsecs--) |
| 464 | { |
| 465 | int count = 0; |
| 466 | unsigned int lines = 0; |
| 467 | unsigned int relocs = 0; |
| 468 | bfd_size_type sec_size = 0; |
| 469 | struct bfd_link_order *l; |
| 470 | struct bfd_link_order *p; |
| 471 | bfd_vma vma = original_sec->vma; |
| 472 | asection *cursor = original_sec; |
| 473 | |
| 474 | /* Count up the relocations and line entries to see if anything |
| 475 | would be too big to fit. Accumulate section size too. */ |
| 476 | for (l = NULL, p = cursor->map_head.link_order; p != NULL; p = l->next) |
| 477 | { |
| 478 | unsigned int thislines = 0; |
| 479 | unsigned int thisrelocs = 0; |
| 480 | bfd_size_type thissize = 0; |
| 481 | if (p->type == bfd_indirect_link_order) |
| 482 | { |
| 483 | asection *sec; |
| 484 | |
| 485 | sec = p->u.indirect.section; |
| 486 | |
| 487 | if (info->strip == strip_none |
| 488 | || info->strip == strip_some) |
| 489 | thislines = sec->lineno_count; |
| 490 | |
| 491 | if (bfd_link_relocatable (info)) |
| 492 | thisrelocs = sec->reloc_count; |
| 493 | |
| 494 | thissize = sec->size; |
| 495 | |
| 496 | } |
| 497 | else if (bfd_link_relocatable (info) |
| 498 | && (p->type == bfd_section_reloc_link_order |
| 499 | || p->type == bfd_symbol_reloc_link_order)) |
| 500 | thisrelocs++; |
| 501 | |
| 502 | if (l != NULL |
| 503 | && (thisrelocs + relocs >= config.split_by_reloc |
| 504 | || thislines + lines >= config.split_by_reloc |
| 505 | || (thissize + sec_size >= config.split_by_file)) |
| 506 | && !unsplittable_name (cursor->name)) |
| 507 | { |
| 508 | /* Create a new section and put this link order and the |
| 509 | following link orders into it. */ |
| 510 | bfd_vma shift_offset; |
| 511 | asection *n; |
| 512 | |
| 513 | n = clone_section (abfd, cursor, original_sec->name, &count); |
| 514 | |
| 515 | /* Attach the link orders to the new section and snip |
| 516 | them off from the old section. */ |
| 517 | n->map_head.link_order = p; |
| 518 | n->map_tail.link_order = cursor->map_tail.link_order; |
| 519 | cursor->map_tail.link_order = l; |
| 520 | l->next = NULL; |
| 521 | l = p; |
| 522 | |
| 523 | /* Change the size of the original section and |
| 524 | update the vma of the new one. */ |
| 525 | |
| 526 | dump ("before snip", cursor, n); |
| 527 | |
| 528 | shift_offset = p->offset; |
| 529 | n->size = cursor->size - shift_offset; |
| 530 | cursor->size = shift_offset; |
| 531 | |
| 532 | vma += shift_offset; |
| 533 | n->lma = n->vma = vma; |
| 534 | |
| 535 | /* Run down the chain and change the output section to |
| 536 | the right one, update the offsets too. */ |
| 537 | do |
| 538 | { |
| 539 | p->offset -= shift_offset; |
| 540 | if (p->type == bfd_indirect_link_order) |
| 541 | { |
| 542 | p->u.indirect.section->output_section = n; |
| 543 | p->u.indirect.section->output_offset = p->offset; |
| 544 | } |
| 545 | p = p->next; |
| 546 | } |
| 547 | while (p); |
| 548 | |
| 549 | dump ("after snip", cursor, n); |
| 550 | cursor = n; |
| 551 | relocs = thisrelocs; |
| 552 | lines = thislines; |
| 553 | sec_size = thissize; |
| 554 | } |
| 555 | else |
| 556 | { |
| 557 | l = p; |
| 558 | relocs += thisrelocs; |
| 559 | lines += thislines; |
| 560 | sec_size += thissize; |
| 561 | } |
| 562 | } |
| 563 | } |
| 564 | sanity_check (abfd); |
| 565 | } |
| 566 | |
| 567 | /* Call BFD to write out the linked file. */ |
| 568 | |
| 569 | void |
| 570 | ldwrite (void) |
| 571 | { |
| 572 | /* Reset error indicator, which can typically something like invalid |
| 573 | format from opening up the .o files. */ |
| 574 | bfd_set_error (bfd_error_no_error); |
| 575 | lang_clear_os_map (); |
| 576 | lang_for_each_statement (build_link_order); |
| 577 | |
| 578 | if (config.split_by_reloc != (unsigned) -1 |
| 579 | || config.split_by_file != (bfd_size_type) -1) |
| 580 | split_sections (link_info.output_bfd, &link_info); |
| 581 | if (!bfd_final_link (link_info.output_bfd, &link_info)) |
| 582 | { |
| 583 | /* If there was an error recorded, print it out. Otherwise assume |
| 584 | an appropriate error message like unknown symbol was printed |
| 585 | out. */ |
| 586 | |
| 587 | if (bfd_get_error () != bfd_error_no_error) |
| 588 | einfo (_("%F%P: final link failed: %E\n")); |
| 589 | else |
| 590 | xexit (1); |
| 591 | } |
| 592 | } |