| 1 | /* Block-relocating memory allocator. |
| 2 | Copyright (C) 1993, 1995, 2000-2013 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GNU Emacs. |
| 5 | |
| 6 | GNU Emacs is free software: you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation, either version 3 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | GNU Emacs is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | /* NOTES: |
| 20 | |
| 21 | Only relocate the blocs necessary for SIZE in r_alloc_sbrk, |
| 22 | rather than all of them. This means allowing for a possible |
| 23 | hole between the first bloc and the end of malloc storage. */ |
| 24 | |
| 25 | #ifdef emacs |
| 26 | |
| 27 | #include <config.h> |
| 28 | |
| 29 | #include "lisp.h" /* Needed for VALBITS. */ |
| 30 | #include "blockinput.h" |
| 31 | |
| 32 | #include <unistd.h> |
| 33 | |
| 34 | #ifdef DOUG_LEA_MALLOC |
| 35 | #define M_TOP_PAD -2 |
| 36 | extern int mallopt (int, int); |
| 37 | #else /* not DOUG_LEA_MALLOC */ |
| 38 | #ifndef SYSTEM_MALLOC |
| 39 | extern size_t __malloc_extra_blocks; |
| 40 | #endif /* SYSTEM_MALLOC */ |
| 41 | #endif /* not DOUG_LEA_MALLOC */ |
| 42 | |
| 43 | #else /* not emacs */ |
| 44 | |
| 45 | #include <stddef.h> |
| 46 | |
| 47 | #include <unistd.h> |
| 48 | #include <malloc.h> |
| 49 | |
| 50 | #endif /* not emacs */ |
| 51 | |
| 52 | |
| 53 | #include "getpagesize.h" |
| 54 | |
| 55 | typedef size_t SIZE; |
| 56 | typedef void *POINTER; |
| 57 | #define NIL ((POINTER) 0) |
| 58 | |
| 59 | /* A flag to indicate whether we have initialized ralloc yet. For |
| 60 | Emacs's sake, please do not make this local to malloc_init; on some |
| 61 | machines, the dumping procedure makes all static variables |
| 62 | read-only. On these machines, the word static is #defined to be |
| 63 | the empty string, meaning that r_alloc_initialized becomes an |
| 64 | automatic variable, and loses its value each time Emacs is started |
| 65 | up. */ |
| 66 | |
| 67 | static int r_alloc_initialized = 0; |
| 68 | |
| 69 | static void r_alloc_init (void); |
| 70 | |
| 71 | \f |
| 72 | /* Declarations for working with the malloc, ralloc, and system breaks. */ |
| 73 | |
| 74 | /* Function to set the real break value. */ |
| 75 | POINTER (*real_morecore) (ptrdiff_t); |
| 76 | |
| 77 | /* The break value, as seen by malloc. */ |
| 78 | static POINTER virtual_break_value; |
| 79 | |
| 80 | /* The address of the end of the last data in use by ralloc, |
| 81 | including relocatable blocs as well as malloc data. */ |
| 82 | static POINTER break_value; |
| 83 | |
| 84 | /* This is the size of a page. We round memory requests to this boundary. */ |
| 85 | static int page_size; |
| 86 | |
| 87 | /* Whenever we get memory from the system, get this many extra bytes. This |
| 88 | must be a multiple of page_size. */ |
| 89 | static int extra_bytes; |
| 90 | |
| 91 | /* Macros for rounding. Note that rounding to any value is possible |
| 92 | by changing the definition of PAGE. */ |
| 93 | #define PAGE (getpagesize ()) |
| 94 | #define ROUNDUP(size) (((size_t) (size) + page_size - 1) \ |
| 95 | & ~((size_t)(page_size - 1))) |
| 96 | |
| 97 | #define MEM_ALIGN sizeof (double) |
| 98 | #define MEM_ROUNDUP(addr) (((size_t)(addr) + MEM_ALIGN - 1) \ |
| 99 | & ~(MEM_ALIGN - 1)) |
| 100 | |
| 101 | /* The hook `malloc' uses for the function which gets more space |
| 102 | from the system. */ |
| 103 | |
| 104 | #ifndef SYSTEM_MALLOC |
| 105 | extern POINTER (*__morecore) (ptrdiff_t); |
| 106 | #endif |
| 107 | |
| 108 | |
| 109 | \f |
| 110 | /*********************************************************************** |
| 111 | Implementation using sbrk |
| 112 | ***********************************************************************/ |
| 113 | |
| 114 | /* Data structures of heaps and blocs. */ |
| 115 | |
| 116 | /* The relocatable objects, or blocs, and the malloc data |
| 117 | both reside within one or more heaps. |
| 118 | Each heap contains malloc data, running from `start' to `bloc_start', |
| 119 | and relocatable objects, running from `bloc_start' to `free'. |
| 120 | |
| 121 | Relocatable objects may relocate within the same heap |
| 122 | or may move into another heap; the heaps themselves may grow |
| 123 | but they never move. |
| 124 | |
| 125 | We try to make just one heap and make it larger as necessary. |
| 126 | But sometimes we can't do that, because we can't get contiguous |
| 127 | space to add onto the heap. When that happens, we start a new heap. */ |
| 128 | |
| 129 | typedef struct heap |
| 130 | { |
| 131 | struct heap *next; |
| 132 | struct heap *prev; |
| 133 | /* Start of memory range of this heap. */ |
| 134 | POINTER start; |
| 135 | /* End of memory range of this heap. */ |
| 136 | POINTER end; |
| 137 | /* Start of relocatable data in this heap. */ |
| 138 | POINTER bloc_start; |
| 139 | /* Start of unused space in this heap. */ |
| 140 | POINTER free; |
| 141 | /* First bloc in this heap. */ |
| 142 | struct bp *first_bloc; |
| 143 | /* Last bloc in this heap. */ |
| 144 | struct bp *last_bloc; |
| 145 | } *heap_ptr; |
| 146 | |
| 147 | #define NIL_HEAP ((heap_ptr) 0) |
| 148 | |
| 149 | /* This is the first heap object. |
| 150 | If we need additional heap objects, each one resides at the beginning of |
| 151 | the space it covers. */ |
| 152 | static struct heap heap_base; |
| 153 | |
| 154 | /* Head and tail of the list of heaps. */ |
| 155 | static heap_ptr first_heap, last_heap; |
| 156 | |
| 157 | /* These structures are allocated in the malloc arena. |
| 158 | The linked list is kept in order of increasing '.data' members. |
| 159 | The data blocks abut each other; if b->next is non-nil, then |
| 160 | b->data + b->size == b->next->data. |
| 161 | |
| 162 | An element with variable==NIL denotes a freed block, which has not yet |
| 163 | been collected. They may only appear while r_alloc_freeze_level > 0, |
| 164 | and will be freed when the arena is thawed. Currently, these blocs are |
| 165 | not reusable, while the arena is frozen. Very inefficient. */ |
| 166 | |
| 167 | typedef struct bp |
| 168 | { |
| 169 | struct bp *next; |
| 170 | struct bp *prev; |
| 171 | POINTER *variable; |
| 172 | POINTER data; |
| 173 | SIZE size; |
| 174 | POINTER new_data; /* temporarily used for relocation */ |
| 175 | struct heap *heap; /* Heap this bloc is in. */ |
| 176 | } *bloc_ptr; |
| 177 | |
| 178 | #define NIL_BLOC ((bloc_ptr) 0) |
| 179 | #define BLOC_PTR_SIZE (sizeof (struct bp)) |
| 180 | |
| 181 | /* Head and tail of the list of relocatable blocs. */ |
| 182 | static bloc_ptr first_bloc, last_bloc; |
| 183 | |
| 184 | static int use_relocatable_buffers; |
| 185 | |
| 186 | /* If >0, no relocation whatsoever takes place. */ |
| 187 | static int r_alloc_freeze_level; |
| 188 | |
| 189 | \f |
| 190 | /* Functions to get and return memory from the system. */ |
| 191 | |
| 192 | /* Find the heap that ADDRESS falls within. */ |
| 193 | |
| 194 | static heap_ptr |
| 195 | find_heap (POINTER address) |
| 196 | { |
| 197 | heap_ptr heap; |
| 198 | |
| 199 | for (heap = last_heap; heap; heap = heap->prev) |
| 200 | { |
| 201 | if (heap->start <= address && address <= heap->end) |
| 202 | return heap; |
| 203 | } |
| 204 | |
| 205 | return NIL_HEAP; |
| 206 | } |
| 207 | |
| 208 | /* Find SIZE bytes of space in a heap. |
| 209 | Try to get them at ADDRESS (which must fall within some heap's range) |
| 210 | if we can get that many within one heap. |
| 211 | |
| 212 | If enough space is not presently available in our reserve, this means |
| 213 | getting more page-aligned space from the system. If the returned space |
| 214 | is not contiguous to the last heap, allocate a new heap, and append it |
| 215 | to the heap list. |
| 216 | |
| 217 | obtain does not try to keep track of whether space is in use or not |
| 218 | in use. It just returns the address of SIZE bytes that fall within a |
| 219 | single heap. If you call obtain twice in a row with the same arguments, |
| 220 | you typically get the same value. It's the caller's responsibility to |
| 221 | keep track of what space is in use. |
| 222 | |
| 223 | Return the address of the space if all went well, or zero if we couldn't |
| 224 | allocate the memory. */ |
| 225 | |
| 226 | static POINTER |
| 227 | obtain (POINTER address, SIZE size) |
| 228 | { |
| 229 | heap_ptr heap; |
| 230 | SIZE already_available; |
| 231 | |
| 232 | /* Find the heap that ADDRESS falls within. */ |
| 233 | for (heap = last_heap; heap; heap = heap->prev) |
| 234 | { |
| 235 | if (heap->start <= address && address <= heap->end) |
| 236 | break; |
| 237 | } |
| 238 | |
| 239 | if (! heap) |
| 240 | emacs_abort (); |
| 241 | |
| 242 | /* If we can't fit SIZE bytes in that heap, |
| 243 | try successive later heaps. */ |
| 244 | while (heap && (char *) address + size > (char *) heap->end) |
| 245 | { |
| 246 | heap = heap->next; |
| 247 | if (heap == NIL_HEAP) |
| 248 | break; |
| 249 | address = heap->bloc_start; |
| 250 | } |
| 251 | |
| 252 | /* If we can't fit them within any existing heap, |
| 253 | get more space. */ |
| 254 | if (heap == NIL_HEAP) |
| 255 | { |
| 256 | POINTER new = (*real_morecore)(0); |
| 257 | SIZE get; |
| 258 | |
| 259 | already_available = (char *)last_heap->end - (char *)address; |
| 260 | |
| 261 | if (new != last_heap->end) |
| 262 | { |
| 263 | /* Someone else called sbrk. Make a new heap. */ |
| 264 | |
| 265 | heap_ptr new_heap = (heap_ptr) MEM_ROUNDUP (new); |
| 266 | POINTER bloc_start = (POINTER) MEM_ROUNDUP ((POINTER)(new_heap + 1)); |
| 267 | |
| 268 | if ((*real_morecore) ((char *) bloc_start - (char *) new) != new) |
| 269 | return 0; |
| 270 | |
| 271 | new_heap->start = new; |
| 272 | new_heap->end = bloc_start; |
| 273 | new_heap->bloc_start = bloc_start; |
| 274 | new_heap->free = bloc_start; |
| 275 | new_heap->next = NIL_HEAP; |
| 276 | new_heap->prev = last_heap; |
| 277 | new_heap->first_bloc = NIL_BLOC; |
| 278 | new_heap->last_bloc = NIL_BLOC; |
| 279 | last_heap->next = new_heap; |
| 280 | last_heap = new_heap; |
| 281 | |
| 282 | address = bloc_start; |
| 283 | already_available = 0; |
| 284 | } |
| 285 | |
| 286 | /* Add space to the last heap (which we may have just created). |
| 287 | Get some extra, so we can come here less often. */ |
| 288 | |
| 289 | get = size + extra_bytes - already_available; |
| 290 | get = (char *) ROUNDUP ((char *)last_heap->end + get) |
| 291 | - (char *) last_heap->end; |
| 292 | |
| 293 | if ((*real_morecore) (get) != last_heap->end) |
| 294 | return 0; |
| 295 | |
| 296 | last_heap->end = (char *) last_heap->end + get; |
| 297 | } |
| 298 | |
| 299 | return address; |
| 300 | } |
| 301 | |
| 302 | /* Return unused heap space to the system |
| 303 | if there is a lot of unused space now. |
| 304 | This can make the last heap smaller; |
| 305 | it can also eliminate the last heap entirely. */ |
| 306 | |
| 307 | static void |
| 308 | relinquish (void) |
| 309 | { |
| 310 | register heap_ptr h; |
| 311 | ptrdiff_t excess = 0; |
| 312 | |
| 313 | /* Add the amount of space beyond break_value |
| 314 | in all heaps which have extend beyond break_value at all. */ |
| 315 | |
| 316 | for (h = last_heap; h && break_value < h->end; h = h->prev) |
| 317 | { |
| 318 | excess += (char *) h->end - (char *) ((break_value < h->bloc_start) |
| 319 | ? h->bloc_start : break_value); |
| 320 | } |
| 321 | |
| 322 | if (excess > extra_bytes * 2 && (*real_morecore) (0) == last_heap->end) |
| 323 | { |
| 324 | /* Keep extra_bytes worth of empty space. |
| 325 | And don't free anything unless we can free at least extra_bytes. */ |
| 326 | excess -= extra_bytes; |
| 327 | |
| 328 | if ((char *)last_heap->end - (char *)last_heap->bloc_start <= excess) |
| 329 | { |
| 330 | heap_ptr lh_prev; |
| 331 | |
| 332 | /* This heap should have no blocs in it. If it does, we |
| 333 | cannot return it to the system. */ |
| 334 | if (last_heap->first_bloc != NIL_BLOC |
| 335 | || last_heap->last_bloc != NIL_BLOC) |
| 336 | return; |
| 337 | |
| 338 | /* Return the last heap, with its header, to the system. */ |
| 339 | excess = (char *)last_heap->end - (char *)last_heap->start; |
| 340 | lh_prev = last_heap->prev; |
| 341 | /* If the system doesn't want that much memory back, leave |
| 342 | last_heap unaltered to reflect that. This can occur if |
| 343 | break_value is still within the original data segment. */ |
| 344 | if ((*real_morecore) (- excess) != 0) |
| 345 | { |
| 346 | last_heap = lh_prev; |
| 347 | last_heap->next = NIL_HEAP; |
| 348 | } |
| 349 | } |
| 350 | else |
| 351 | { |
| 352 | excess = (char *) last_heap->end |
| 353 | - (char *) ROUNDUP ((char *)last_heap->end - excess); |
| 354 | /* If the system doesn't want that much memory back, leave |
| 355 | the end of the last heap unchanged to reflect that. This |
| 356 | can occur if break_value is still within the original |
| 357 | data segment. */ |
| 358 | if ((*real_morecore) (- excess) != 0) |
| 359 | last_heap->end = (char *) last_heap->end - excess; |
| 360 | } |
| 361 | } |
| 362 | } |
| 363 | \f |
| 364 | /* The meat - allocating, freeing, and relocating blocs. */ |
| 365 | |
| 366 | /* Find the bloc referenced by the address in PTR. Returns a pointer |
| 367 | to that block. */ |
| 368 | |
| 369 | static bloc_ptr |
| 370 | find_bloc (POINTER *ptr) |
| 371 | { |
| 372 | register bloc_ptr p = first_bloc; |
| 373 | |
| 374 | while (p != NIL_BLOC) |
| 375 | { |
| 376 | /* Consistency check. Don't return inconsistent blocs. |
| 377 | Don't abort here, as callers might be expecting this, but |
| 378 | callers that always expect a bloc to be returned should abort |
| 379 | if one isn't to avoid a memory corruption bug that is |
| 380 | difficult to track down. */ |
| 381 | if (p->variable == ptr && p->data == *ptr) |
| 382 | return p; |
| 383 | |
| 384 | p = p->next; |
| 385 | } |
| 386 | |
| 387 | return p; |
| 388 | } |
| 389 | |
| 390 | /* Allocate a bloc of SIZE bytes and append it to the chain of blocs. |
| 391 | Returns a pointer to the new bloc, or zero if we couldn't allocate |
| 392 | memory for the new block. */ |
| 393 | |
| 394 | static bloc_ptr |
| 395 | get_bloc (SIZE size) |
| 396 | { |
| 397 | register bloc_ptr new_bloc; |
| 398 | register heap_ptr heap; |
| 399 | |
| 400 | if (! (new_bloc = malloc (BLOC_PTR_SIZE)) |
| 401 | || ! (new_bloc->data = obtain (break_value, size))) |
| 402 | { |
| 403 | free (new_bloc); |
| 404 | |
| 405 | return 0; |
| 406 | } |
| 407 | |
| 408 | break_value = (char *) new_bloc->data + size; |
| 409 | |
| 410 | new_bloc->size = size; |
| 411 | new_bloc->next = NIL_BLOC; |
| 412 | new_bloc->variable = (POINTER *) NIL; |
| 413 | new_bloc->new_data = 0; |
| 414 | |
| 415 | /* Record in the heap that this space is in use. */ |
| 416 | heap = find_heap (new_bloc->data); |
| 417 | heap->free = break_value; |
| 418 | |
| 419 | /* Maintain the correspondence between heaps and blocs. */ |
| 420 | new_bloc->heap = heap; |
| 421 | heap->last_bloc = new_bloc; |
| 422 | if (heap->first_bloc == NIL_BLOC) |
| 423 | heap->first_bloc = new_bloc; |
| 424 | |
| 425 | /* Put this bloc on the doubly-linked list of blocs. */ |
| 426 | if (first_bloc) |
| 427 | { |
| 428 | new_bloc->prev = last_bloc; |
| 429 | last_bloc->next = new_bloc; |
| 430 | last_bloc = new_bloc; |
| 431 | } |
| 432 | else |
| 433 | { |
| 434 | first_bloc = last_bloc = new_bloc; |
| 435 | new_bloc->prev = NIL_BLOC; |
| 436 | } |
| 437 | |
| 438 | return new_bloc; |
| 439 | } |
| 440 | \f |
| 441 | /* Calculate new locations of blocs in the list beginning with BLOC, |
| 442 | relocating it to start at ADDRESS, in heap HEAP. If enough space is |
| 443 | not presently available in our reserve, call obtain for |
| 444 | more space. |
| 445 | |
| 446 | Store the new location of each bloc in its new_data field. |
| 447 | Do not touch the contents of blocs or break_value. */ |
| 448 | |
| 449 | static int |
| 450 | relocate_blocs (bloc_ptr bloc, heap_ptr heap, POINTER address) |
| 451 | { |
| 452 | register bloc_ptr b = bloc; |
| 453 | |
| 454 | /* No need to ever call this if arena is frozen, bug somewhere! */ |
| 455 | if (r_alloc_freeze_level) |
| 456 | emacs_abort (); |
| 457 | |
| 458 | while (b) |
| 459 | { |
| 460 | /* If bloc B won't fit within HEAP, |
| 461 | move to the next heap and try again. */ |
| 462 | while (heap && (char *) address + b->size > (char *) heap->end) |
| 463 | { |
| 464 | heap = heap->next; |
| 465 | if (heap == NIL_HEAP) |
| 466 | break; |
| 467 | address = heap->bloc_start; |
| 468 | } |
| 469 | |
| 470 | /* If BLOC won't fit in any heap, |
| 471 | get enough new space to hold BLOC and all following blocs. */ |
| 472 | if (heap == NIL_HEAP) |
| 473 | { |
| 474 | register bloc_ptr tb = b; |
| 475 | register SIZE s = 0; |
| 476 | |
| 477 | /* Add up the size of all the following blocs. */ |
| 478 | while (tb != NIL_BLOC) |
| 479 | { |
| 480 | if (tb->variable) |
| 481 | s += tb->size; |
| 482 | |
| 483 | tb = tb->next; |
| 484 | } |
| 485 | |
| 486 | /* Get that space. */ |
| 487 | address = obtain (address, s); |
| 488 | if (address == 0) |
| 489 | return 0; |
| 490 | |
| 491 | heap = last_heap; |
| 492 | } |
| 493 | |
| 494 | /* Record the new address of this bloc |
| 495 | and update where the next bloc can start. */ |
| 496 | b->new_data = address; |
| 497 | if (b->variable) |
| 498 | address = (char *) address + b->size; |
| 499 | b = b->next; |
| 500 | } |
| 501 | |
| 502 | return 1; |
| 503 | } |
| 504 | \f |
| 505 | /* Update the records of which heaps contain which blocs, starting |
| 506 | with heap HEAP and bloc BLOC. */ |
| 507 | |
| 508 | static void |
| 509 | update_heap_bloc_correspondence (bloc_ptr bloc, heap_ptr heap) |
| 510 | { |
| 511 | register bloc_ptr b; |
| 512 | |
| 513 | /* Initialize HEAP's status to reflect blocs before BLOC. */ |
| 514 | if (bloc != NIL_BLOC && bloc->prev != NIL_BLOC && bloc->prev->heap == heap) |
| 515 | { |
| 516 | /* The previous bloc is in HEAP. */ |
| 517 | heap->last_bloc = bloc->prev; |
| 518 | heap->free = (char *) bloc->prev->data + bloc->prev->size; |
| 519 | } |
| 520 | else |
| 521 | { |
| 522 | /* HEAP contains no blocs before BLOC. */ |
| 523 | heap->first_bloc = NIL_BLOC; |
| 524 | heap->last_bloc = NIL_BLOC; |
| 525 | heap->free = heap->bloc_start; |
| 526 | } |
| 527 | |
| 528 | /* Advance through blocs one by one. */ |
| 529 | for (b = bloc; b != NIL_BLOC; b = b->next) |
| 530 | { |
| 531 | /* Advance through heaps, marking them empty, |
| 532 | till we get to the one that B is in. */ |
| 533 | while (heap) |
| 534 | { |
| 535 | if (heap->bloc_start <= b->data && b->data <= heap->end) |
| 536 | break; |
| 537 | heap = heap->next; |
| 538 | /* We know HEAP is not null now, |
| 539 | because there has to be space for bloc B. */ |
| 540 | heap->first_bloc = NIL_BLOC; |
| 541 | heap->last_bloc = NIL_BLOC; |
| 542 | heap->free = heap->bloc_start; |
| 543 | } |
| 544 | |
| 545 | /* Update HEAP's status for bloc B. */ |
| 546 | heap->free = (char *) b->data + b->size; |
| 547 | heap->last_bloc = b; |
| 548 | if (heap->first_bloc == NIL_BLOC) |
| 549 | heap->first_bloc = b; |
| 550 | |
| 551 | /* Record that B is in HEAP. */ |
| 552 | b->heap = heap; |
| 553 | } |
| 554 | |
| 555 | /* If there are any remaining heaps and no blocs left, |
| 556 | mark those heaps as empty. */ |
| 557 | heap = heap->next; |
| 558 | while (heap) |
| 559 | { |
| 560 | heap->first_bloc = NIL_BLOC; |
| 561 | heap->last_bloc = NIL_BLOC; |
| 562 | heap->free = heap->bloc_start; |
| 563 | heap = heap->next; |
| 564 | } |
| 565 | } |
| 566 | \f |
| 567 | /* Resize BLOC to SIZE bytes. This relocates the blocs |
| 568 | that come after BLOC in memory. */ |
| 569 | |
| 570 | static int |
| 571 | resize_bloc (bloc_ptr bloc, SIZE size) |
| 572 | { |
| 573 | register bloc_ptr b; |
| 574 | heap_ptr heap; |
| 575 | POINTER address; |
| 576 | SIZE old_size; |
| 577 | |
| 578 | /* No need to ever call this if arena is frozen, bug somewhere! */ |
| 579 | if (r_alloc_freeze_level) |
| 580 | emacs_abort (); |
| 581 | |
| 582 | if (bloc == NIL_BLOC || size == bloc->size) |
| 583 | return 1; |
| 584 | |
| 585 | for (heap = first_heap; heap != NIL_HEAP; heap = heap->next) |
| 586 | { |
| 587 | if (heap->bloc_start <= bloc->data && bloc->data <= heap->end) |
| 588 | break; |
| 589 | } |
| 590 | |
| 591 | if (heap == NIL_HEAP) |
| 592 | emacs_abort (); |
| 593 | |
| 594 | old_size = bloc->size; |
| 595 | bloc->size = size; |
| 596 | |
| 597 | /* Note that bloc could be moved into the previous heap. */ |
| 598 | address = (bloc->prev ? (char *) bloc->prev->data + bloc->prev->size |
| 599 | : (char *) first_heap->bloc_start); |
| 600 | while (heap) |
| 601 | { |
| 602 | if (heap->bloc_start <= address && address <= heap->end) |
| 603 | break; |
| 604 | heap = heap->prev; |
| 605 | } |
| 606 | |
| 607 | if (! relocate_blocs (bloc, heap, address)) |
| 608 | { |
| 609 | bloc->size = old_size; |
| 610 | return 0; |
| 611 | } |
| 612 | |
| 613 | if (size > old_size) |
| 614 | { |
| 615 | for (b = last_bloc; b != bloc; b = b->prev) |
| 616 | { |
| 617 | if (!b->variable) |
| 618 | { |
| 619 | b->size = 0; |
| 620 | b->data = b->new_data; |
| 621 | } |
| 622 | else |
| 623 | { |
| 624 | if (b->new_data != b->data) |
| 625 | memmove (b->new_data, b->data, b->size); |
| 626 | *b->variable = b->data = b->new_data; |
| 627 | } |
| 628 | } |
| 629 | if (!bloc->variable) |
| 630 | { |
| 631 | bloc->size = 0; |
| 632 | bloc->data = bloc->new_data; |
| 633 | } |
| 634 | else |
| 635 | { |
| 636 | if (bloc->new_data != bloc->data) |
| 637 | memmove (bloc->new_data, bloc->data, old_size); |
| 638 | memset ((char *) bloc->new_data + old_size, 0, size - old_size); |
| 639 | *bloc->variable = bloc->data = bloc->new_data; |
| 640 | } |
| 641 | } |
| 642 | else |
| 643 | { |
| 644 | for (b = bloc; b != NIL_BLOC; b = b->next) |
| 645 | { |
| 646 | if (!b->variable) |
| 647 | { |
| 648 | b->size = 0; |
| 649 | b->data = b->new_data; |
| 650 | } |
| 651 | else |
| 652 | { |
| 653 | if (b->new_data != b->data) |
| 654 | memmove (b->new_data, b->data, b->size); |
| 655 | *b->variable = b->data = b->new_data; |
| 656 | } |
| 657 | } |
| 658 | } |
| 659 | |
| 660 | update_heap_bloc_correspondence (bloc, heap); |
| 661 | |
| 662 | break_value = (last_bloc ? (char *) last_bloc->data + last_bloc->size |
| 663 | : (char *) first_heap->bloc_start); |
| 664 | return 1; |
| 665 | } |
| 666 | \f |
| 667 | /* Free BLOC from the chain of blocs, relocating any blocs above it. |
| 668 | This may return space to the system. */ |
| 669 | |
| 670 | static void |
| 671 | free_bloc (bloc_ptr bloc) |
| 672 | { |
| 673 | heap_ptr heap = bloc->heap; |
| 674 | heap_ptr h; |
| 675 | |
| 676 | if (r_alloc_freeze_level) |
| 677 | { |
| 678 | bloc->variable = (POINTER *) NIL; |
| 679 | return; |
| 680 | } |
| 681 | |
| 682 | resize_bloc (bloc, 0); |
| 683 | |
| 684 | if (bloc == first_bloc && bloc == last_bloc) |
| 685 | { |
| 686 | first_bloc = last_bloc = NIL_BLOC; |
| 687 | } |
| 688 | else if (bloc == last_bloc) |
| 689 | { |
| 690 | last_bloc = bloc->prev; |
| 691 | last_bloc->next = NIL_BLOC; |
| 692 | } |
| 693 | else if (bloc == first_bloc) |
| 694 | { |
| 695 | first_bloc = bloc->next; |
| 696 | first_bloc->prev = NIL_BLOC; |
| 697 | } |
| 698 | else |
| 699 | { |
| 700 | bloc->next->prev = bloc->prev; |
| 701 | bloc->prev->next = bloc->next; |
| 702 | } |
| 703 | |
| 704 | /* Sometimes, 'heap' obtained from bloc->heap above is not really a |
| 705 | 'heap' structure. It can even be beyond the current break point, |
| 706 | which will cause crashes when we dereference it below (see |
| 707 | bug#12242). Evidently, the reason is bloc allocations done while |
| 708 | use_relocatable_buffers was non-positive, because additional |
| 709 | memory we get then is not recorded in the heaps we manage. If |
| 710 | bloc->heap records such a "heap", we cannot (and don't need to) |
| 711 | update its records. So we validate the 'heap' value by making |
| 712 | sure it is one of the heaps we manage via the heaps linked list, |
| 713 | and don't touch a 'heap' that isn't found there. This avoids |
| 714 | accessing memory we know nothing about. */ |
| 715 | for (h = first_heap; h != NIL_HEAP; h = h->next) |
| 716 | if (heap == h) |
| 717 | break; |
| 718 | |
| 719 | if (h) |
| 720 | { |
| 721 | /* Update the records of which blocs are in HEAP. */ |
| 722 | if (heap->first_bloc == bloc) |
| 723 | { |
| 724 | if (bloc->next != 0 && bloc->next->heap == heap) |
| 725 | heap->first_bloc = bloc->next; |
| 726 | else |
| 727 | heap->first_bloc = heap->last_bloc = NIL_BLOC; |
| 728 | } |
| 729 | if (heap->last_bloc == bloc) |
| 730 | { |
| 731 | if (bloc->prev != 0 && bloc->prev->heap == heap) |
| 732 | heap->last_bloc = bloc->prev; |
| 733 | else |
| 734 | heap->first_bloc = heap->last_bloc = NIL_BLOC; |
| 735 | } |
| 736 | } |
| 737 | |
| 738 | relinquish (); |
| 739 | free (bloc); |
| 740 | } |
| 741 | \f |
| 742 | /* Interface routines. */ |
| 743 | |
| 744 | /* Obtain SIZE bytes of storage from the free pool, or the system, as |
| 745 | necessary. If relocatable blocs are in use, this means relocating |
| 746 | them. This function gets plugged into the GNU malloc's __morecore |
| 747 | hook. |
| 748 | |
| 749 | We provide hysteresis, never relocating by less than extra_bytes. |
| 750 | |
| 751 | If we're out of memory, we should return zero, to imitate the other |
| 752 | __morecore hook values - in particular, __default_morecore in the |
| 753 | GNU malloc package. */ |
| 754 | |
| 755 | static POINTER |
| 756 | r_alloc_sbrk (ptrdiff_t size) |
| 757 | { |
| 758 | register bloc_ptr b; |
| 759 | POINTER address; |
| 760 | |
| 761 | if (! r_alloc_initialized) |
| 762 | r_alloc_init (); |
| 763 | |
| 764 | if (use_relocatable_buffers <= 0) |
| 765 | return (*real_morecore) (size); |
| 766 | |
| 767 | if (size == 0) |
| 768 | return virtual_break_value; |
| 769 | |
| 770 | if (size > 0) |
| 771 | { |
| 772 | /* Allocate a page-aligned space. GNU malloc would reclaim an |
| 773 | extra space if we passed an unaligned one. But we could |
| 774 | not always find a space which is contiguous to the previous. */ |
| 775 | POINTER new_bloc_start; |
| 776 | heap_ptr h = first_heap; |
| 777 | SIZE get = ROUNDUP (size); |
| 778 | |
| 779 | address = (POINTER) ROUNDUP (virtual_break_value); |
| 780 | |
| 781 | /* Search the list upward for a heap which is large enough. */ |
| 782 | while ((char *) h->end < (char *) MEM_ROUNDUP ((char *)address + get)) |
| 783 | { |
| 784 | h = h->next; |
| 785 | if (h == NIL_HEAP) |
| 786 | break; |
| 787 | address = (POINTER) ROUNDUP (h->start); |
| 788 | } |
| 789 | |
| 790 | /* If not found, obtain more space. */ |
| 791 | if (h == NIL_HEAP) |
| 792 | { |
| 793 | get += extra_bytes + page_size; |
| 794 | |
| 795 | if (! obtain (address, get)) |
| 796 | return 0; |
| 797 | |
| 798 | if (first_heap == last_heap) |
| 799 | address = (POINTER) ROUNDUP (virtual_break_value); |
| 800 | else |
| 801 | address = (POINTER) ROUNDUP (last_heap->start); |
| 802 | h = last_heap; |
| 803 | } |
| 804 | |
| 805 | new_bloc_start = (POINTER) MEM_ROUNDUP ((char *)address + get); |
| 806 | |
| 807 | if (first_heap->bloc_start < new_bloc_start) |
| 808 | { |
| 809 | /* This is no clean solution - no idea how to do it better. */ |
| 810 | if (r_alloc_freeze_level) |
| 811 | return NIL; |
| 812 | |
| 813 | /* There is a bug here: if the above obtain call succeeded, but the |
| 814 | relocate_blocs call below does not succeed, we need to free |
| 815 | the memory that we got with obtain. */ |
| 816 | |
| 817 | /* Move all blocs upward. */ |
| 818 | if (! relocate_blocs (first_bloc, h, new_bloc_start)) |
| 819 | return 0; |
| 820 | |
| 821 | /* Note that (POINTER)(h+1) <= new_bloc_start since |
| 822 | get >= page_size, so the following does not destroy the heap |
| 823 | header. */ |
| 824 | for (b = last_bloc; b != NIL_BLOC; b = b->prev) |
| 825 | { |
| 826 | if (b->new_data != b->data) |
| 827 | memmove (b->new_data, b->data, b->size); |
| 828 | *b->variable = b->data = b->new_data; |
| 829 | } |
| 830 | |
| 831 | h->bloc_start = new_bloc_start; |
| 832 | |
| 833 | update_heap_bloc_correspondence (first_bloc, h); |
| 834 | } |
| 835 | if (h != first_heap) |
| 836 | { |
| 837 | /* Give up managing heaps below the one the new |
| 838 | virtual_break_value points to. */ |
| 839 | first_heap->prev = NIL_HEAP; |
| 840 | first_heap->next = h->next; |
| 841 | first_heap->start = h->start; |
| 842 | first_heap->end = h->end; |
| 843 | first_heap->free = h->free; |
| 844 | first_heap->first_bloc = h->first_bloc; |
| 845 | first_heap->last_bloc = h->last_bloc; |
| 846 | first_heap->bloc_start = h->bloc_start; |
| 847 | |
| 848 | if (first_heap->next) |
| 849 | first_heap->next->prev = first_heap; |
| 850 | else |
| 851 | last_heap = first_heap; |
| 852 | } |
| 853 | |
| 854 | memset (address, 0, size); |
| 855 | } |
| 856 | else /* size < 0 */ |
| 857 | { |
| 858 | SIZE excess = (char *)first_heap->bloc_start |
| 859 | - ((char *)virtual_break_value + size); |
| 860 | |
| 861 | address = virtual_break_value; |
| 862 | |
| 863 | if (r_alloc_freeze_level == 0 && excess > 2 * extra_bytes) |
| 864 | { |
| 865 | excess -= extra_bytes; |
| 866 | first_heap->bloc_start |
| 867 | = (POINTER) MEM_ROUNDUP ((char *)first_heap->bloc_start - excess); |
| 868 | |
| 869 | relocate_blocs (first_bloc, first_heap, first_heap->bloc_start); |
| 870 | |
| 871 | for (b = first_bloc; b != NIL_BLOC; b = b->next) |
| 872 | { |
| 873 | if (b->new_data != b->data) |
| 874 | memmove (b->new_data, b->data, b->size); |
| 875 | *b->variable = b->data = b->new_data; |
| 876 | } |
| 877 | } |
| 878 | |
| 879 | if ((char *)virtual_break_value + size < (char *)first_heap->start) |
| 880 | { |
| 881 | /* We found an additional space below the first heap */ |
| 882 | first_heap->start = (POINTER) ((char *)virtual_break_value + size); |
| 883 | } |
| 884 | } |
| 885 | |
| 886 | virtual_break_value = (POINTER) ((char *)address + size); |
| 887 | break_value = (last_bloc |
| 888 | ? (char *) last_bloc->data + last_bloc->size |
| 889 | : (char *) first_heap->bloc_start); |
| 890 | if (size < 0) |
| 891 | relinquish (); |
| 892 | |
| 893 | return address; |
| 894 | } |
| 895 | |
| 896 | |
| 897 | /* Allocate a relocatable bloc of storage of size SIZE. A pointer to |
| 898 | the data is returned in *PTR. PTR is thus the address of some variable |
| 899 | which will use the data area. |
| 900 | |
| 901 | The allocation of 0 bytes is valid. |
| 902 | In case r_alloc_freeze_level is set, a best fit of unused blocs could be |
| 903 | done before allocating a new area. Not yet done. |
| 904 | |
| 905 | If we can't allocate the necessary memory, set *PTR to zero, and |
| 906 | return zero. */ |
| 907 | |
| 908 | POINTER |
| 909 | r_alloc (POINTER *ptr, SIZE size) |
| 910 | { |
| 911 | register bloc_ptr new_bloc; |
| 912 | |
| 913 | if (! r_alloc_initialized) |
| 914 | r_alloc_init (); |
| 915 | |
| 916 | new_bloc = get_bloc (MEM_ROUNDUP (size)); |
| 917 | if (new_bloc) |
| 918 | { |
| 919 | new_bloc->variable = ptr; |
| 920 | *ptr = new_bloc->data; |
| 921 | } |
| 922 | else |
| 923 | *ptr = 0; |
| 924 | |
| 925 | return *ptr; |
| 926 | } |
| 927 | |
| 928 | /* Free a bloc of relocatable storage whose data is pointed to by PTR. |
| 929 | Store 0 in *PTR to show there's no block allocated. */ |
| 930 | |
| 931 | void |
| 932 | r_alloc_free (register POINTER *ptr) |
| 933 | { |
| 934 | register bloc_ptr dead_bloc; |
| 935 | |
| 936 | if (! r_alloc_initialized) |
| 937 | r_alloc_init (); |
| 938 | |
| 939 | dead_bloc = find_bloc (ptr); |
| 940 | if (dead_bloc == NIL_BLOC) |
| 941 | emacs_abort (); /* Double free? PTR not originally used to allocate? */ |
| 942 | |
| 943 | free_bloc (dead_bloc); |
| 944 | *ptr = 0; |
| 945 | |
| 946 | #ifdef emacs |
| 947 | refill_memory_reserve (); |
| 948 | #endif |
| 949 | } |
| 950 | |
| 951 | /* Given a pointer at address PTR to relocatable data, resize it to SIZE. |
| 952 | Do this by shifting all blocks above this one up in memory, unless |
| 953 | SIZE is less than or equal to the current bloc size, in which case |
| 954 | do nothing. |
| 955 | |
| 956 | In case r_alloc_freeze_level is set, a new bloc is allocated, and the |
| 957 | memory copied to it. Not very efficient. We could traverse the |
| 958 | bloc_list for a best fit of free blocs first. |
| 959 | |
| 960 | Change *PTR to reflect the new bloc, and return this value. |
| 961 | |
| 962 | If more memory cannot be allocated, then leave *PTR unchanged, and |
| 963 | return zero. */ |
| 964 | |
| 965 | POINTER |
| 966 | r_re_alloc (POINTER *ptr, SIZE size) |
| 967 | { |
| 968 | register bloc_ptr bloc; |
| 969 | |
| 970 | if (! r_alloc_initialized) |
| 971 | r_alloc_init (); |
| 972 | |
| 973 | if (!*ptr) |
| 974 | return r_alloc (ptr, size); |
| 975 | if (!size) |
| 976 | { |
| 977 | r_alloc_free (ptr); |
| 978 | return r_alloc (ptr, 0); |
| 979 | } |
| 980 | |
| 981 | bloc = find_bloc (ptr); |
| 982 | if (bloc == NIL_BLOC) |
| 983 | emacs_abort (); /* Already freed? PTR not originally used to allocate? */ |
| 984 | |
| 985 | if (size < bloc->size) |
| 986 | { |
| 987 | /* Wouldn't it be useful to actually resize the bloc here? */ |
| 988 | /* I think so too, but not if it's too expensive... */ |
| 989 | if ((bloc->size - MEM_ROUNDUP (size) >= page_size) |
| 990 | && r_alloc_freeze_level == 0) |
| 991 | { |
| 992 | resize_bloc (bloc, MEM_ROUNDUP (size)); |
| 993 | /* Never mind if this fails, just do nothing... */ |
| 994 | /* It *should* be infallible! */ |
| 995 | } |
| 996 | } |
| 997 | else if (size > bloc->size) |
| 998 | { |
| 999 | if (r_alloc_freeze_level) |
| 1000 | { |
| 1001 | bloc_ptr new_bloc; |
| 1002 | new_bloc = get_bloc (MEM_ROUNDUP (size)); |
| 1003 | if (new_bloc) |
| 1004 | { |
| 1005 | new_bloc->variable = ptr; |
| 1006 | *ptr = new_bloc->data; |
| 1007 | bloc->variable = (POINTER *) NIL; |
| 1008 | } |
| 1009 | else |
| 1010 | return NIL; |
| 1011 | } |
| 1012 | else |
| 1013 | { |
| 1014 | if (! resize_bloc (bloc, MEM_ROUNDUP (size))) |
| 1015 | return NIL; |
| 1016 | } |
| 1017 | } |
| 1018 | return *ptr; |
| 1019 | } |
| 1020 | |
| 1021 | |
| 1022 | #if defined (emacs) && defined (DOUG_LEA_MALLOC) |
| 1023 | |
| 1024 | /* Reinitialize the morecore hook variables after restarting a dumped |
| 1025 | Emacs. This is needed when using Doug Lea's malloc from GNU libc. */ |
| 1026 | void |
| 1027 | r_alloc_reinit (void) |
| 1028 | { |
| 1029 | /* Only do this if the hook has been reset, so that we don't get an |
| 1030 | infinite loop, in case Emacs was linked statically. */ |
| 1031 | if (__morecore != r_alloc_sbrk) |
| 1032 | { |
| 1033 | real_morecore = __morecore; |
| 1034 | __morecore = r_alloc_sbrk; |
| 1035 | } |
| 1036 | } |
| 1037 | |
| 1038 | #endif /* emacs && DOUG_LEA_MALLOC */ |
| 1039 | |
| 1040 | #ifdef DEBUG |
| 1041 | |
| 1042 | #include <assert.h> |
| 1043 | |
| 1044 | void |
| 1045 | r_alloc_check (void) |
| 1046 | { |
| 1047 | int found = 0; |
| 1048 | heap_ptr h, ph = 0; |
| 1049 | bloc_ptr b, pb = 0; |
| 1050 | |
| 1051 | if (!r_alloc_initialized) |
| 1052 | return; |
| 1053 | |
| 1054 | assert (first_heap); |
| 1055 | assert (last_heap->end <= (POINTER) sbrk (0)); |
| 1056 | assert ((POINTER) first_heap < first_heap->start); |
| 1057 | assert (first_heap->start <= virtual_break_value); |
| 1058 | assert (virtual_break_value <= first_heap->end); |
| 1059 | |
| 1060 | for (h = first_heap; h; h = h->next) |
| 1061 | { |
| 1062 | assert (h->prev == ph); |
| 1063 | assert ((POINTER) ROUNDUP (h->end) == h->end); |
| 1064 | #if 0 /* ??? The code in ralloc.c does not really try to ensure |
| 1065 | the heap start has any sort of alignment. |
| 1066 | Perhaps it should. */ |
| 1067 | assert ((POINTER) MEM_ROUNDUP (h->start) == h->start); |
| 1068 | #endif |
| 1069 | assert ((POINTER) MEM_ROUNDUP (h->bloc_start) == h->bloc_start); |
| 1070 | assert (h->start <= h->bloc_start && h->bloc_start <= h->end); |
| 1071 | |
| 1072 | if (ph) |
| 1073 | { |
| 1074 | assert (ph->end < h->start); |
| 1075 | assert (h->start <= (POINTER)h && (POINTER)(h+1) <= h->bloc_start); |
| 1076 | } |
| 1077 | |
| 1078 | if (h->bloc_start <= break_value && break_value <= h->end) |
| 1079 | found = 1; |
| 1080 | |
| 1081 | ph = h; |
| 1082 | } |
| 1083 | |
| 1084 | assert (found); |
| 1085 | assert (last_heap == ph); |
| 1086 | |
| 1087 | for (b = first_bloc; b; b = b->next) |
| 1088 | { |
| 1089 | assert (b->prev == pb); |
| 1090 | assert ((POINTER) MEM_ROUNDUP (b->data) == b->data); |
| 1091 | assert ((SIZE) MEM_ROUNDUP (b->size) == b->size); |
| 1092 | |
| 1093 | ph = 0; |
| 1094 | for (h = first_heap; h; h = h->next) |
| 1095 | { |
| 1096 | if (h->bloc_start <= b->data && b->data + b->size <= h->end) |
| 1097 | break; |
| 1098 | ph = h; |
| 1099 | } |
| 1100 | |
| 1101 | assert (h); |
| 1102 | |
| 1103 | if (pb && pb->data + pb->size != b->data) |
| 1104 | { |
| 1105 | assert (ph && b->data == h->bloc_start); |
| 1106 | while (ph) |
| 1107 | { |
| 1108 | if (ph->bloc_start <= pb->data |
| 1109 | && pb->data + pb->size <= ph->end) |
| 1110 | { |
| 1111 | assert (pb->data + pb->size + b->size > ph->end); |
| 1112 | break; |
| 1113 | } |
| 1114 | else |
| 1115 | { |
| 1116 | assert (ph->bloc_start + b->size > ph->end); |
| 1117 | } |
| 1118 | ph = ph->prev; |
| 1119 | } |
| 1120 | } |
| 1121 | pb = b; |
| 1122 | } |
| 1123 | |
| 1124 | assert (last_bloc == pb); |
| 1125 | |
| 1126 | if (last_bloc) |
| 1127 | assert (last_bloc->data + last_bloc->size == break_value); |
| 1128 | else |
| 1129 | assert (first_heap->bloc_start == break_value); |
| 1130 | } |
| 1131 | |
| 1132 | #endif /* DEBUG */ |
| 1133 | |
| 1134 | /* Update the internal record of which variable points to some data to NEW. |
| 1135 | Used by buffer-swap-text in Emacs to restore consistency after it |
| 1136 | swaps the buffer text between two buffer objects. The OLD pointer |
| 1137 | is checked to ensure that memory corruption does not occur due to |
| 1138 | misuse. */ |
| 1139 | void |
| 1140 | r_alloc_reset_variable (POINTER *old, POINTER *new) |
| 1141 | { |
| 1142 | bloc_ptr bloc = first_bloc; |
| 1143 | |
| 1144 | /* Find the bloc that corresponds to the data pointed to by pointer. |
| 1145 | find_bloc cannot be used, as it has internal consistency checks |
| 1146 | which fail when the variable needs resetting. */ |
| 1147 | while (bloc != NIL_BLOC) |
| 1148 | { |
| 1149 | if (bloc->data == *new) |
| 1150 | break; |
| 1151 | |
| 1152 | bloc = bloc->next; |
| 1153 | } |
| 1154 | |
| 1155 | if (bloc == NIL_BLOC || bloc->variable != old) |
| 1156 | emacs_abort (); /* Already freed? OLD not originally used to allocate? */ |
| 1157 | |
| 1158 | /* Update variable to point to the new location. */ |
| 1159 | bloc->variable = new; |
| 1160 | } |
| 1161 | |
| 1162 | void |
| 1163 | r_alloc_inhibit_buffer_relocation (int inhibit) |
| 1164 | { |
| 1165 | if (use_relocatable_buffers > 1) |
| 1166 | use_relocatable_buffers = 1; |
| 1167 | if (inhibit) |
| 1168 | use_relocatable_buffers--; |
| 1169 | else if (use_relocatable_buffers < 1) |
| 1170 | use_relocatable_buffers++; |
| 1171 | } |
| 1172 | |
| 1173 | \f |
| 1174 | /*********************************************************************** |
| 1175 | Initialization |
| 1176 | ***********************************************************************/ |
| 1177 | |
| 1178 | /* Initialize various things for memory allocation. */ |
| 1179 | |
| 1180 | static void |
| 1181 | r_alloc_init (void) |
| 1182 | { |
| 1183 | if (r_alloc_initialized) |
| 1184 | return; |
| 1185 | r_alloc_initialized = 1; |
| 1186 | |
| 1187 | page_size = PAGE; |
| 1188 | #ifndef SYSTEM_MALLOC |
| 1189 | real_morecore = __morecore; |
| 1190 | __morecore = r_alloc_sbrk; |
| 1191 | |
| 1192 | first_heap = last_heap = &heap_base; |
| 1193 | first_heap->next = first_heap->prev = NIL_HEAP; |
| 1194 | first_heap->start = first_heap->bloc_start |
| 1195 | = virtual_break_value = break_value = (*real_morecore) (0); |
| 1196 | if (break_value == NIL) |
| 1197 | emacs_abort (); |
| 1198 | |
| 1199 | extra_bytes = ROUNDUP (50000); |
| 1200 | #endif |
| 1201 | |
| 1202 | #ifdef DOUG_LEA_MALLOC |
| 1203 | block_input (); |
| 1204 | mallopt (M_TOP_PAD, 64 * 4096); |
| 1205 | unblock_input (); |
| 1206 | #else |
| 1207 | #ifndef SYSTEM_MALLOC |
| 1208 | /* Give GNU malloc's morecore some hysteresis so that we move all |
| 1209 | the relocatable blocks much less often. The number used to be |
| 1210 | 64, but alloc.c would override that with 32 in code that was |
| 1211 | removed when SYNC_INPUT became the only input handling mode. |
| 1212 | That code was conditioned on !DOUG_LEA_MALLOC, so the call to |
| 1213 | mallopt above is left unchanged. (Actually, I think there's no |
| 1214 | system nowadays that uses DOUG_LEA_MALLOC and also uses |
| 1215 | REL_ALLOC.) */ |
| 1216 | __malloc_extra_blocks = 32; |
| 1217 | #endif |
| 1218 | #endif |
| 1219 | |
| 1220 | #ifndef SYSTEM_MALLOC |
| 1221 | first_heap->end = (POINTER) ROUNDUP (first_heap->start); |
| 1222 | |
| 1223 | /* The extra call to real_morecore guarantees that the end of the |
| 1224 | address space is a multiple of page_size, even if page_size is |
| 1225 | not really the page size of the system running the binary in |
| 1226 | which page_size is stored. This allows a binary to be built on a |
| 1227 | system with one page size and run on a system with a smaller page |
| 1228 | size. */ |
| 1229 | (*real_morecore) ((char *) first_heap->end - (char *) first_heap->start); |
| 1230 | |
| 1231 | /* Clear the rest of the last page; this memory is in our address space |
| 1232 | even though it is after the sbrk value. */ |
| 1233 | /* Doubly true, with the additional call that explicitly adds the |
| 1234 | rest of that page to the address space. */ |
| 1235 | memset (first_heap->start, 0, |
| 1236 | (char *) first_heap->end - (char *) first_heap->start); |
| 1237 | virtual_break_value = break_value = first_heap->bloc_start = first_heap->end; |
| 1238 | #endif |
| 1239 | |
| 1240 | use_relocatable_buffers = 1; |
| 1241 | } |