alloc.c 121 KB
Newer Older
Jim Blandy's avatar
Jim Blandy committed
1
/* Storage allocation and gc for GNU Emacs Lisp interpreter.
2
   Copyright (C) 1985, 86, 88, 93, 94, 95, 97, 98, 1999, 2000
Richard M. Stallman's avatar
Richard M. Stallman committed
3
      Free Software Foundation, Inc.
Jim Blandy's avatar
Jim Blandy committed
4 5 6 7 8

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
9
the Free Software Foundation; either version 2, or (at your option)
Jim Blandy's avatar
Jim Blandy committed
10 11 12 13 14 15 16 17 18
any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to
19 20
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */
Jim Blandy's avatar
Jim Blandy committed
21

22
#include <config.h>
23
#include <stdio.h>
24

25
/* Note that this declares bzero on OSF/1.  How dumb.  */
26

27
#include <signal.h>
28

29 30 31
/* This file is part of the core Lisp implementation, and thus must
   deal with the real data structures.  If the Lisp implementation is
   replaced, this file likely will not be used.  */
32

33
#undef HIDE_LISP_IMPLEMENTATION
Jim Blandy's avatar
Jim Blandy committed
34
#include "lisp.h"
35
#include "intervals.h"
Jim Blandy's avatar
Jim Blandy committed
36
#include "puresize.h"
Jim Blandy's avatar
Jim Blandy committed
37 38
#include "buffer.h"
#include "window.h"
Jim Blandy's avatar
Jim Blandy committed
39
#include "frame.h"
40
#include "blockinput.h"
Richard M. Stallman's avatar
Richard M. Stallman committed
41
#include "keyboard.h"
42
#include "charset.h"
Jim Blandy's avatar
Jim Blandy committed
43
#include "syssignal.h"
44
#include <setjmp.h>
Jim Blandy's avatar
Jim Blandy committed
45

Karl Heuer's avatar
Karl Heuer committed
46 47
extern char *sbrk ();

48
#ifdef DOUG_LEA_MALLOC
49

50 51
#include <malloc.h>
#define __malloc_size_t int
52

53 54 55
/* Specify maximum number of areas to mmap.  It would be nice to use a
   value that explicitly means "no limit".  */

56 57
#define MMAP_MAX_AREAS 100000000

58 59
#else /* not DOUG_LEA_MALLOC */

60 61
/* The following come from gmalloc.c.  */

62
#if defined (STDC_HEADERS)
63 64 65 66 67 68 69
#include <stddef.h>
#define	__malloc_size_t		size_t
#else
#define	__malloc_size_t		unsigned int
#endif
extern __malloc_size_t _bytes_used;
extern int __malloc_extra_blocks;
70 71

#endif /* not DOUG_LEA_MALLOC */
72

Jim Blandy's avatar
Jim Blandy committed
73
#define max(A,B) ((A) > (B) ? (A) : (B))
74
#define min(A,B) ((A) < (B) ? (A) : (B))
Jim Blandy's avatar
Jim Blandy committed
75 76 77 78 79

/* Macro to verify that storage intended for Lisp objects is not
   out of range to fit in the space for a pointer.
   ADDRESS is the start of the block, and SIZE
   is the amount of space within which objects can start.  */
80

Jim Blandy's avatar
Jim Blandy committed
81 82 83 84
#define VALIDATE_LISP_STORAGE(address, size)			\
do								\
  {								\
    Lisp_Object val;						\
85
    XSETCONS (val, (char *) address + size);		\
Jim Blandy's avatar
Jim Blandy committed
86 87
    if ((char *) XCONS (val) != (char *) address + size)	\
      {								\
88
	xfree (address);					\
Jim Blandy's avatar
Jim Blandy committed
89 90 91 92
	memory_full ();						\
      }								\
  } while (0)

93
/* Value of _bytes_used, when spare_memory was freed.  */
94

95 96
static __malloc_size_t bytes_used_when_full;

97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113
/* Mark, unmark, query mark bit of a Lisp string.  S must be a pointer
   to a struct Lisp_String.  */

#define MARK_STRING(S)		XMARK ((S)->size)
#define UNMARK_STRING(S)	XUNMARK ((S)->size)
#define STRING_MARKED_P(S)	XMARKBIT ((S)->size)

/* Value is the number of bytes/chars of S, a pointer to a struct
   Lisp_String.  This must be used instead of STRING_BYTES (S) or
   S->size during GC, because S->size contains the mark bit for
   strings.  */

#define GC_STRING_BYTES(S)	(STRING_BYTES (S) & ~MARKBIT)
#define GC_STRING_CHARS(S)	((S)->size & ~MARKBIT)

/* Number of bytes of consing done since the last gc.  */

Jim Blandy's avatar
Jim Blandy committed
114 115
int consing_since_gc;

116
/* Count the amount of consing of various sorts of space.  */
117

118 119 120 121 122 123 124
int cons_cells_consed;
int floats_consed;
int vector_cells_consed;
int symbols_consed;
int string_chars_consed;
int misc_objects_consed;
int intervals_consed;
125 126 127
int strings_consed;

/* Number of bytes of consing since GC before another GC should be done. */
128

129
int gc_cons_threshold;
Jim Blandy's avatar
Jim Blandy committed
130

131 132
/* Nonzero during GC.  */

Jim Blandy's avatar
Jim Blandy committed
133 134
int gc_in_progress;

135
/* Nonzero means display messages at beginning and end of GC.  */
136

137 138
int garbage_collection_messages;

Jim Blandy's avatar
Jim Blandy committed
139 140 141
#ifndef VIRT_ADDR_VARIES
extern
#endif /* VIRT_ADDR_VARIES */
142
int malloc_sbrk_used;
Jim Blandy's avatar
Jim Blandy committed
143 144 145 146

#ifndef VIRT_ADDR_VARIES
extern
#endif /* VIRT_ADDR_VARIES */
147
int malloc_sbrk_unused;
Jim Blandy's avatar
Jim Blandy committed
148

Jim Blandy's avatar
Jim Blandy committed
149
/* Two limits controlling how much undo information to keep.  */
150

Jim Blandy's avatar
Jim Blandy committed
151 152
int undo_limit;
int undo_strong_limit;
Jim Blandy's avatar
Jim Blandy committed
153

154 155 156 157 158
/* Number of live and free conses etc.  */

static int total_conses, total_markers, total_symbols, total_vector_size;
static int total_free_conses, total_free_markers, total_free_symbols;
static int total_free_floats, total_floats;
159

160 161 162
/* Points to memory space allocated as "spare", to be freed if we run
   out of memory.  */

163 164 165
static char *spare_memory;

/* Amount of spare memory to keep in reserve.  */
166

167 168 169
#define SPARE_MEMORY (1 << 14)

/* Number of extra blocks malloc should get when it needs more core.  */
170

171 172
static int malloc_hysteresis;

173 174 175
/* Nonzero when malloc is called for allocating Lisp object space.
   Currently set but not used.  */

Karl Heuer's avatar
Karl Heuer committed
176 177
int allocating_for_lisp;

178 179
/* Non-nil means defun should do purecopy on the function definition.  */

Jim Blandy's avatar
Jim Blandy committed
180 181 182
Lisp_Object Vpurify_flag;

#ifndef HAVE_SHM
183 184 185 186

/* Force it into data space! */

EMACS_INT pure[PURESIZE / sizeof (EMACS_INT)] = {0,};
Jim Blandy's avatar
Jim Blandy committed
187
#define PUREBEG (char *) pure
188 189 190

#else /* not HAVE_SHM */

Jim Blandy's avatar
Jim Blandy committed
191 192
#define pure PURE_SEG_BITS   /* Use shared memory segment */
#define PUREBEG (char *)PURE_SEG_BITS
Jim Blandy's avatar
Jim Blandy committed
193 194 195

/* This variable is used only by the XPNTR macro when HAVE_SHM is
   defined.  If we used the PURESIZE macro directly there, that would
196
   make most of Emacs dependent on puresize.h, which we don't want -
Jim Blandy's avatar
Jim Blandy committed
197 198 199
   you should be able to change that without too much recompilation.
   So map_in_data initializes pure_size, and the dependencies work
   out.  */
200

201
EMACS_INT pure_size;
202

Jim Blandy's avatar
Jim Blandy committed
203 204
#endif /* not HAVE_SHM */

205 206 207 208 209 210 211 212
/* Value is non-zero if P points into pure space.  */

#define PURE_POINTER_P(P)					\
     (((PNTR_COMPARISON_TYPE) (P)				\
       < (PNTR_COMPARISON_TYPE) ((char *) pure + PURESIZE))	\
      && ((PNTR_COMPARISON_TYPE) (P)				\
	  >= (PNTR_COMPARISON_TYPE) pure))

213 214
/* Index in pure at which next pure object will be allocated.. */

Jim Blandy's avatar
Jim Blandy committed
215 216
int pureptr;

217 218 219
/* If nonzero, this is a warning delivered by malloc and not yet
   displayed.  */

Jim Blandy's avatar
Jim Blandy committed
220 221
char *pending_malloc_warning;

222
/* Pre-computed signal argument for use when memory is exhausted.  */
223

224
Lisp_Object memory_signal_data;
225

Jim Blandy's avatar
Jim Blandy committed
226 227 228 229 230 231 232 233 234 235 236
/* Maximum amount of C stack to save when a GC happens.  */

#ifndef MAX_SAVE_STACK
#define MAX_SAVE_STACK 16000
#endif

/* Buffer in which we save a copy of the C stack at each GC.  */

char *stack_copy;
int stack_copy_size;

237 238 239
/* Non-zero means ignore malloc warnings.  Set during initialization.
   Currently not used.  */

Jim Blandy's avatar
Jim Blandy committed
240
int ignore_warnings;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
241

242
Lisp_Object Qgc_cons_threshold, Qchar_table_extra_slots;
243

244 245 246
static void mark_buffer P_ ((Lisp_Object));
static void mark_kboards P_ ((void));
static void gc_sweep P_ ((void));
247 248 249 250 251 252 253 254
static void mark_glyph_matrix P_ ((struct glyph_matrix *));
static void mark_face_cache P_ ((struct face_cache *));

#ifdef HAVE_WINDOW_SYSTEM
static void mark_image P_ ((struct image *));
static void mark_image_cache P_ ((struct frame *));
#endif /* HAVE_WINDOW_SYSTEM */

255 256 257 258
static struct Lisp_String *allocate_string P_ ((void));
static void compact_small_strings P_ ((void));
static void free_large_strings P_ ((void));
static void sweep_strings P_ ((void));
Richard M. Stallman's avatar
Richard M. Stallman committed
259 260

extern int message_enable_multibyte;
261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277

/* When scanning the C stack for live Lisp objects, Emacs keeps track
   of what memory allocated via lisp_malloc is intended for what
   purpose.  This enumeration specifies the type of memory.  */

enum mem_type
{
  MEM_TYPE_NON_LISP,
  MEM_TYPE_BUFFER,
  MEM_TYPE_CONS,
  MEM_TYPE_STRING,
  MEM_TYPE_MISC,
  MEM_TYPE_SYMBOL,
  MEM_TYPE_FLOAT,
  MEM_TYPE_VECTOR
};

278 279 280 281 282 283 284 285 286 287 288
#if GC_MARK_STACK

#if GC_MARK_STACK == GC_USE_GCPROS_CHECK_ZOMBIES
#include <stdio.h>		/* For fprintf.  */
#endif

/* A unique object in pure space used to make some Lisp objects
   on free lists recognizable in O(1).  */

Lisp_Object Vdead;

289 290 291 292 293 294 295 296 297 298 299
struct mem_node;
static void *lisp_malloc P_ ((int, enum mem_type));
static void mark_stack P_ ((void));
static void init_stack P_ ((Lisp_Object *));
static int live_vector_p P_ ((struct mem_node *, void *));
static int live_buffer_p P_ ((struct mem_node *, void *));
static int live_string_p P_ ((struct mem_node *, void *));
static int live_cons_p P_ ((struct mem_node *, void *));
static int live_symbol_p P_ ((struct mem_node *, void *));
static int live_float_p P_ ((struct mem_node *, void *));
static int live_misc_p P_ ((struct mem_node *, void *));
300
static void mark_maybe_object P_ ((Lisp_Object));
301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316
static void mark_memory P_ ((void *, void *));
static void mem_init P_ ((void));
static struct mem_node *mem_insert P_ ((void *, void *, enum mem_type));
static void mem_insert_fixup P_ ((struct mem_node *));
static void mem_rotate_left P_ ((struct mem_node *));
static void mem_rotate_right P_ ((struct mem_node *));
static void mem_delete P_ ((struct mem_node *));
static void mem_delete_fixup P_ ((struct mem_node *));
static INLINE struct mem_node *mem_find P_ ((void *));

#if GC_MARK_STACK == GC_MARK_STACK_CHECK_GCPROS
static void check_gcpros P_ ((void));
#endif

#endif /* GC_MARK_STACK != 0 */

Jim Blandy's avatar
Jim Blandy committed
317

318 319 320 321 322 323
/************************************************************************
				Malloc
 ************************************************************************/

/* Write STR to Vstandard_output plus some advice on how to free some
   memory.  Called when memory gets low.  */
324

Jim Blandy's avatar
Jim Blandy committed
325 326 327 328 329 330 331 332 333 334 335
Lisp_Object
malloc_warning_1 (str)
     Lisp_Object str;
{
  Fprinc (str, Vstandard_output);
  write_string ("\nKilling some buffers may delay running out of memory.\n", -1);
  write_string ("However, certainly by the time you receive the 95% warning,\n", -1);
  write_string ("you should clean up, kill this Emacs, and start a new one.", -1);
  return Qnil;
}

336 337 338

/* Function malloc calls this if it finds we are near exhausting
   storage.  */
339 340

void
Jim Blandy's avatar
Jim Blandy committed
341 342 343 344 345 346
malloc_warning (str)
     char *str;
{
  pending_malloc_warning = str;
}

347 348 349

/* Display a malloc warning in buffer *Danger*.  */

350
void
Jim Blandy's avatar
Jim Blandy committed
351 352 353 354 355 356 357 358 359
display_malloc_warning ()
{
  register Lisp_Object val;

  val = build_string (pending_malloc_warning);
  pending_malloc_warning = 0;
  internal_with_output_to_temp_buffer (" *Danger*", malloc_warning_1, val);
}

360

361
#ifdef DOUG_LEA_MALLOC
362
#  define BYTES_USED (mallinfo ().arena)
363
#else
364
#  define BYTES_USED _bytes_used
365 366
#endif

367

368
/* Called if malloc returns zero.  */
369

370
void
Jim Blandy's avatar
Jim Blandy committed
371 372
memory_full ()
{
373
#ifndef SYSTEM_MALLOC
374
  bytes_used_when_full = BYTES_USED;
375 376 377 378 379 380 381 382 383
#endif

  /* The first time we get here, free the spare memory.  */
  if (spare_memory)
    {
      free (spare_memory);
      spare_memory = 0;
    }

384 385
  /* This used to call error, but if we've run out of memory, we could
     get infinite recursion trying to build the string.  */
386
  while (1)
387
    Fsignal (Qnil, memory_signal_data);
388 389
}

390

391 392 393 394 395
/* Called if we can't allocate relocatable space for a buffer.  */

void
buffer_memory_full ()
{
396 397 398 399 400 401
  /* If buffers use the relocating allocator, no need to free
     spare_memory, because we may have plenty of malloc space left
     that we could get, and if we don't, the malloc that fails will
     itself cause spare_memory to be freed.  If buffers don't use the
     relocating allocator, treat this like any other failing
     malloc.  */
402 403 404 405 406

#ifndef REL_ALLOC
  memory_full ();
#endif

407 408
  /* This used to call error, but if we've run out of memory, we could
     get infinite recursion trying to build the string.  */
409 410
  while (1)
    Fsignal (Qerror, memory_signal_data);
Jim Blandy's avatar
Jim Blandy committed
411 412
}

413 414

/* Like malloc but check for no memory and block interrupt input..  */
Jim Blandy's avatar
Jim Blandy committed
415 416 417 418 419 420 421

long *
xmalloc (size)
     int size;
{
  register long *val;

422
  BLOCK_INPUT;
Jim Blandy's avatar
Jim Blandy committed
423
  val = (long *) malloc (size);
424
  UNBLOCK_INPUT;
Jim Blandy's avatar
Jim Blandy committed
425

426 427
  if (!val && size)
    memory_full ();
Jim Blandy's avatar
Jim Blandy committed
428 429 430
  return val;
}

431 432 433

/* Like realloc but check for no memory and block interrupt input..  */

Jim Blandy's avatar
Jim Blandy committed
434 435 436 437 438 439 440
long *
xrealloc (block, size)
     long *block;
     int size;
{
  register long *val;

441
  BLOCK_INPUT;
Jim Blandy's avatar
Jim Blandy committed
442 443 444 445
  /* We must call malloc explicitly when BLOCK is 0, since some
     reallocs don't do this.  */
  if (! block)
    val = (long *) malloc (size);
Noah Friedman's avatar
Noah Friedman committed
446
  else
Jim Blandy's avatar
Jim Blandy committed
447
    val = (long *) realloc (block, size);
448
  UNBLOCK_INPUT;
Jim Blandy's avatar
Jim Blandy committed
449 450 451 452

  if (!val && size) memory_full ();
  return val;
}
453

454 455 456

/* Like free but block interrupt input..  */

457 458 459 460 461 462 463 464 465
void
xfree (block)
     long *block;
{
  BLOCK_INPUT;
  free (block);
  UNBLOCK_INPUT;
}

466

467 468 469 470 471 472 473 474
/* Like malloc but used for allocating Lisp data.  NBYTES is the
   number of bytes to allocate, TYPE describes the intended use of the
   allcated memory block (for strings, for conses, ...).  */

static void *
lisp_malloc (nbytes, type)
     int nbytes;
     enum mem_type type;
475
{
476
  register void *val;
477 478 479

  BLOCK_INPUT;
  allocating_for_lisp++;
480
  val = (void *) malloc (nbytes);
481 482 483
  allocating_for_lisp--;
  UNBLOCK_INPUT;

484 485 486 487 488 489 490 491
  if (!val && nbytes)
    memory_full ();
  
#if GC_MARK_STACK
  if (type != MEM_TYPE_NON_LISP)
    mem_insert (val, (char *) val + nbytes, type);
#endif
  
492 493 494
  return val;
}

495 496 497 498 499 500 501 502 503 504 505 506 507 508 509

/* Return a new buffer structure allocated from the heap with
   a call to lisp_malloc.  */

struct buffer *
allocate_buffer ()
{
  return (struct buffer *) lisp_malloc (sizeof (struct buffer),
					MEM_TYPE_BUFFER);
}


/* Free BLOCK.  This must be called to free memory allocated with a
   call to lisp_malloc.  */

510 511 512 513 514 515 516
void
lisp_free (block)
     long *block;
{
  BLOCK_INPUT;
  allocating_for_lisp++;
  free (block);
517 518 519
#if GC_MARK_STACK
  mem_delete (mem_find (block));
#endif
520 521 522
  allocating_for_lisp--;
  UNBLOCK_INPUT;
}
523

524 525 526 527 528 529 530 531 532 533 534 535

/* Arranging to disable input signals while we're in malloc.

   This only works with GNU malloc.  To help out systems which can't
   use GNU malloc, all the calls to malloc, realloc, and free
   elsewhere in the code should be inside a BLOCK_INPUT/UNBLOCK_INPUT
   pairs; unfortunately, we have no idea what C library functions
   might call malloc, so we can't really protect them unless you're
   using GNU malloc.  Fortunately, most of the major operating can use
   GNU malloc.  */

#ifndef SYSTEM_MALLOC
536

537 538 539 540 541 542
extern void * (*__malloc_hook) ();
static void * (*old_malloc_hook) ();
extern void * (*__realloc_hook) ();
static void * (*old_realloc_hook) ();
extern void (*__free_hook) ();
static void (*old_free_hook) ();
543

544 545
/* This function is used as the hook for free to call.  */

546 547 548 549 550 551 552
static void
emacs_blocked_free (ptr)
     void *ptr;
{
  BLOCK_INPUT;
  __free_hook = old_free_hook;
  free (ptr);
553 554 555 556 557 558 559 560 561
  /* If we released our reserve (due to running out of memory),
     and we have a fair amount free once again,
     try to set aside another reserve in case we run out once more.  */
  if (spare_memory == 0
      /* Verify there is enough space that even with the malloc
	 hysteresis this call won't run out again.
	 The code here is correct as long as SPARE_MEMORY
	 is substantially larger than the block size malloc uses.  */
      && (bytes_used_when_full
562
	  > BYTES_USED + max (malloc_hysteresis, 4) * SPARE_MEMORY))
563 564
    spare_memory = (char *) malloc (SPARE_MEMORY);

565
  __free_hook = emacs_blocked_free;
566 567 568
  UNBLOCK_INPUT;
}

569

570 571 572 573 574 575 576 577 578 579 580 581 582
/* If we released our reserve (due to running out of memory),
   and we have a fair amount free once again,
   try to set aside another reserve in case we run out once more.

   This is called when a relocatable block is freed in ralloc.c.  */

void
refill_memory_reserve ()
{
  if (spare_memory == 0)
    spare_memory = (char *) malloc (SPARE_MEMORY);
}

583

584 585
/* This function is the malloc hook that Emacs uses.  */

586 587 588 589 590 591 592 593
static void *
emacs_blocked_malloc (size)
     unsigned size;
{
  void *value;

  BLOCK_INPUT;
  __malloc_hook = old_malloc_hook;
594
#ifdef DOUG_LEA_MALLOC
595
    mallopt (M_TOP_PAD, malloc_hysteresis * 4096);
596
#else
597
    __malloc_extra_blocks = malloc_hysteresis;
598
#endif
599
  value = (void *) malloc (size);
600
  __malloc_hook = emacs_blocked_malloc;
601 602 603 604 605
  UNBLOCK_INPUT;

  return value;
}

606 607 608

/* This function is the realloc hook that Emacs uses.  */

609 610 611 612 613 614 615 616 617
static void *
emacs_blocked_realloc (ptr, size)
     void *ptr;
     unsigned size;
{
  void *value;

  BLOCK_INPUT;
  __realloc_hook = old_realloc_hook;
618
  value = (void *) realloc (ptr, size);
619
  __realloc_hook = emacs_blocked_realloc;
620 621 622 623 624
  UNBLOCK_INPUT;

  return value;
}

625 626 627

/* Called from main to set up malloc to use our hooks.  */

628 629 630
void
uninterrupt_malloc ()
{
631 632
  if (__free_hook != emacs_blocked_free)
    old_free_hook = __free_hook;
633
  __free_hook = emacs_blocked_free;
634

635 636
  if (__malloc_hook != emacs_blocked_malloc)
    old_malloc_hook = __malloc_hook;
637
  __malloc_hook = emacs_blocked_malloc;
638

639 640
  if (__realloc_hook != emacs_blocked_realloc)
    old_realloc_hook = __realloc_hook;
641
  __realloc_hook = emacs_blocked_realloc;
642
}
643 644 645 646

#endif /* not SYSTEM_MALLOC */


Jim Blandy's avatar
Jim Blandy committed
647

648 649 650
/***********************************************************************
			 Interval Allocation
 ***********************************************************************/
651

652 653 654
/* Number of intervals allocated in an interval_block structure.
   The 1020 is 1024 minus malloc overhead.  */

655 656 657
#define INTERVAL_BLOCK_SIZE \
  ((1020 - sizeof (struct interval_block *)) / sizeof (struct interval))

658 659 660
/* Intervals are allocated in chunks in form of an interval_block
   structure.  */

661
struct interval_block
662 663 664 665
{
  struct interval_block *next;
  struct interval intervals[INTERVAL_BLOCK_SIZE];
};
666

667 668 669
/* Current interval block.  Its `next' pointer points to older
   blocks.  */

670
struct interval_block *interval_block;
671 672 673 674

/* Index in interval_block above of the next unused interval
   structure.  */

675
static int interval_block_index;
676 677 678

/* Number of free and live intervals.  */

679
static int total_free_intervals, total_intervals;
680

681 682
/* List of free intervals.  */

683 684
INTERVAL interval_free_list;

685
/* Total number of interval blocks now in use.  */
686

687 688
int n_interval_blocks;

689 690 691

/* Initialize interval allocation.  */

692 693 694 695
static void
init_intervals ()
{
  interval_block
696 697
    = (struct interval_block *) lisp_malloc (sizeof *interval_block,
					     MEM_TYPE_NON_LISP);
698
  interval_block->next = 0;
Richard M. Stallman's avatar
Richard M. Stallman committed
699
  bzero ((char *) interval_block->intervals, sizeof interval_block->intervals);
700 701
  interval_block_index = 0;
  interval_free_list = 0;
702
  n_interval_blocks = 1;
703 704
}

705 706

/* Return a new interval.  */
707 708 709 710 711 712 713 714 715

INTERVAL
make_interval ()
{
  INTERVAL val;

  if (interval_free_list)
    {
      val = interval_free_list;
716
      interval_free_list = INTERVAL_PARENT (interval_free_list);
717 718 719 720 721
    }
  else
    {
      if (interval_block_index == INTERVAL_BLOCK_SIZE)
	{
Karl Heuer's avatar
Karl Heuer committed
722 723
	  register struct interval_block *newi;

724 725
	  newi = (struct interval_block *) lisp_malloc (sizeof *newi,
							MEM_TYPE_NON_LISP);
726 727 728 729 730

	  VALIDATE_LISP_STORAGE (newi, sizeof *newi);
	  newi->next = interval_block;
	  interval_block = newi;
	  interval_block_index = 0;
731
	  n_interval_blocks++;
732 733 734 735
	}
      val = &interval_block->intervals[interval_block_index++];
    }
  consing_since_gc += sizeof (struct interval);
736
  intervals_consed++;
737 738 739 740
  RESET_INTERVAL (val);
  return val;
}

741 742

/* Mark Lisp objects in interval I. */
743 744

static void
745
mark_interval (i, dummy)
746
     register INTERVAL i;
747
     Lisp_Object dummy;
748 749 750 751 752 753 754
{
  if (XMARKBIT (i->plist))
    abort ();
  mark_object (&i->plist);
  XMARK (i->plist);
}

755 756 757 758

/* Mark the interval tree rooted in TREE.  Don't call this directly;
   use the macro MARK_INTERVAL_TREE instead.  */

759 760 761 762
static void
mark_interval_tree (tree)
     register INTERVAL tree;
{
763 764 765 766 767 768
  /* No need to test if this tree has been marked already; this
     function is always called through the MARK_INTERVAL_TREE macro,
     which takes care of that.  */

  /* XMARK expands to an assignment; the LHS of an assignment can't be
     a cast.  */
769
  XMARK (tree->up.obj);
770

771
  traverse_intervals (tree, 1, 0, mark_interval, Qnil);
772 773
}

774 775 776

/* Mark the interval tree rooted in I.  */

777 778 779
#define MARK_INTERVAL_TREE(i)				\
  do {							\
    if (!NULL_INTERVAL_P (i)				\
780
	&& ! XMARKBIT (i->up.obj))			\
781 782
      mark_interval_tree (i);				\
  } while (0)
783

784

785
/* The oddity in the call to XUNMARK is necessary because XUNMARK
786 787 788 789 790 791 792
   expands to an assignment to its argument, and most C compilers
   don't support casts on the left operand of `='.  */

#define UNMARK_BALANCE_INTERVALS(i)			\
  do {							\
   if (! NULL_INTERVAL_P (i))				\
     {							\
793
       XUNMARK ((i)->up.obj);				\
794 795 796
       (i) = balance_intervals (i);			\
     }							\
  } while (0)
797

798

799

800 801 802
/***********************************************************************
			  String Allocation
 ***********************************************************************/
803

804 805 806 807 808 809
/* Lisp_Strings are allocated in string_block structures.  When a new
   string_block is allocated, all the Lisp_Strings it contains are
   added to a free-list stiing_free_list.  When a new Lisp_String is
   needed, it is taken from that list.  During the sweep phase of GC,
   string_blocks that are entirely free are freed, except two which
   we keep.
Jim Blandy's avatar
Jim Blandy committed
810

811 812 813
   String data is allocated from sblock structures.  Strings larger
   than LARGE_STRING_BYTES, get their own sblock, data for smaller
   strings is sub-allocated out of sblocks of size SBLOCK_SIZE.
Jim Blandy's avatar
Jim Blandy committed
814

815 816 817 818
   Sblocks consist internally of sdata structures, one for each
   Lisp_String.  The sdata structure points to the Lisp_String it
   belongs to.  The Lisp_String points back to the `u.data' member of
   its sdata structure.
Jim Blandy's avatar
Jim Blandy committed
819

820 821 822 823 824 825
   When a Lisp_String is freed during GC, it is put back on
   string_free_list, and its `data' member and its sdata's `string'
   pointer is set to null.  The size of the string is recorded in the
   `u.nbytes' member of the sdata.  So, sdata structures that are no
   longer used, can be easily recognized, and it's easy to compact the
   sblocks of small strings which we do in compact_small_strings.  */
Jim Blandy's avatar
Jim Blandy committed
826

827 828
/* Size in bytes of an sblock structure used for small strings.  This
   is 8192 minus malloc overhead.  */
Jim Blandy's avatar
Jim Blandy committed
829

830
#define SBLOCK_SIZE 8188
831

832 833
/* Strings larger than this are considered large strings.  String data
   for large strings is allocated from individual sblocks.  */
Jim Blandy's avatar
Jim Blandy committed
834

835 836 837 838 839 840
#define LARGE_STRING_BYTES 1024

/* Structure describing string memory sub-allocated from an sblock.
   This is where the contents of Lisp strings are stored.  */

struct sdata
Jim Blandy's avatar
Jim Blandy committed
841
{
842 843
  /* Back-pointer to the string this sdata belongs to.  If null, this
     structure is free, and the NBYTES member of the union below
844
     contains the string's byte size (the same value that STRING_BYTES
845 846 847 848
     would return if STRING were non-null).  If non-null, STRING_BYTES
     (STRING) is the size of the data, and DATA contains the string's
     contents.  */
  struct Lisp_String *string;
Jim Blandy's avatar
Jim Blandy committed
849

850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865
  union
  {
    /* When STRING in non-null.  */
    unsigned char data[1];

    /* When STRING is null.  */
    EMACS_INT nbytes;
  } u;
};

/* Structure describing a block of memory which is sub-allocated to
   obtain string data memory for strings.  Blocks for small strings
   are of fixed size SBLOCK_SIZE.  Blocks for large strings are made
   as large as needed.  */

struct sblock
Jim Blandy's avatar
Jim Blandy committed
866
{
867 868
  /* Next in list.  */
  struct sblock *next;
Jim Blandy's avatar
Jim Blandy committed
869

870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887
  /* Pointer to the next free sdata block.  This points past the end
     of the sblock if there isn't any space left in this block.  */
  struct sdata *next_free;

  /* Start of data.  */
  struct sdata first_data;
};

/* Number of Lisp strings in a string_block structure.  The 1020 is
   1024 minus malloc overhead.  */

#define STRINGS_IN_STRING_BLOCK \
  ((1020 - sizeof (struct string_block *)) / sizeof (struct Lisp_String))

/* Structure describing a block from which Lisp_String structures
   are allocated.  */

struct string_block
Jim Blandy's avatar
Jim Blandy committed
888
{
889 890 891
  struct string_block *next;
  struct Lisp_String strings[STRINGS_IN_STRING_BLOCK];
};
Jim Blandy's avatar
Jim Blandy committed
892

893 894 895
/* Head and tail of the list of sblock structures holding Lisp string
   data.  We always allocate from current_sblock.  The NEXT pointers
   in the sblock structures go from oldest_sblock to current_sblock.  */
Karl Heuer's avatar
Karl Heuer committed
896

897
static struct sblock *oldest_sblock, *current_sblock;
Jim Blandy's avatar
Jim Blandy committed
898

899
/* List of sblocks for large strings.  */
Jim Blandy's avatar
Jim Blandy committed
900

901
static struct sblock *large_sblocks;
Jim Blandy's avatar
Jim Blandy committed
902

903
/* List of string_block structures, and how many there are.  */
Jim Blandy's avatar
Jim Blandy committed
904

905 906
static struct string_block *string_blocks;
static int n_string_blocks;
Jim Blandy's avatar
Jim Blandy committed
907

908
/* Free-list of Lisp_Strings.  */
Jim Blandy's avatar
Jim Blandy committed
909

910
static struct Lisp_String *string_free_list;
Jim Blandy's avatar
Jim Blandy committed
911

912
/* Number of live and free Lisp_Strings.  */
913

914
static int total_strings, total_free_strings;
Jim Blandy's avatar
Jim Blandy committed
915

916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945
/* Number of bytes used by live strings.  */

static int total_string_size;

/* Given a pointer to a Lisp_String S which is on the free-list
   string_free_list, return a pointer to its successor in the
   free-list.  */

#define NEXT_FREE_LISP_STRING(S) (*(struct Lisp_String **) (S))

/* Return a pointer to the sdata structure belonging to Lisp string S.
   S must be live, i.e. S->data must not be null.  S->data is actually
   a pointer to the `u.data' member of its sdata structure; the
   structure starts at a constant offset in front of that.  */
   
#define SDATA_OF_STRING(S) \
     ((struct sdata *) ((S)->data - sizeof (struct Lisp_String *)))

/* Value is the size of an sdata structure large enough to hold NBYTES
   bytes of string data.  The value returned includes a terminating
   NUL byte, the size of the sdata structure, and padding.  */

#define SDATA_SIZE(NBYTES)			\
     ((sizeof (struct Lisp_String *)		\
       + (NBYTES) + 1				\
       + sizeof (EMACS_INT) - 1)		\
      & ~(sizeof (EMACS_INT) - 1))


/* Initialize string allocation.  Called from init_alloc_once.  */
946 947

void
948
init_strings ()
Jim Blandy's avatar
Jim Blandy committed
949
{
950 951 952 953 954
  total_strings = total_free_strings = total_string_size = 0;
  oldest_sblock = current_sblock = large_sblocks = NULL;
  string_blocks = NULL;
  n_string_blocks = 0;
  string_free_list = NULL;
Jim Blandy's avatar
Jim Blandy committed
955 956
}

957 958 959 960 961

/* Return a new Lisp_String.  */

static struct Lisp_String *
allocate_string ()
Jim Blandy's avatar
Jim Blandy committed
962
{
963
  struct Lisp_String *s;
Jim Blandy's avatar
Jim Blandy committed
964

965 966 967
  /* If the free-list is empty, allocate a new string_block, and
     add all the Lisp_Strings in it to the free-list.  */
  if (string_free_list == NULL)
Jim Blandy's avatar
Jim Blandy committed
968
    {
969 970 971
      struct string_block *b;
      int i;

972
      b = (struct string_block *) lisp_malloc (sizeof *b, MEM_TYPE_STRING);
973 974 975 976 977 978 979
      VALIDATE_LISP_STORAGE (b, sizeof *b);
      bzero (b, sizeof *b);
      b->next = string_blocks;
      string_blocks = b;
      ++n_string_blocks;

      for (i = STRINGS_IN_STRING_BLOCK - 1; i >= 0; --i)
Jim Blandy's avatar
Jim Blandy committed
980
	{
981 982 983
	  s = b->strings + i;
	  NEXT_FREE_LISP_STRING (s) = string_free_list;
	  string_free_list = s;
Jim Blandy's avatar
Jim Blandy committed
984
	}
985 986

      total_free_strings += STRINGS_IN_STRING_BLOCK;
Jim Blandy's avatar
Jim Blandy committed
987
    }
988

989 990 991
  /* Pop a Lisp_String off the free-list.  */
  s = string_free_list;
  string_free_list = NEXT_FREE_LISP_STRING (s);
992

993 994
  /* Probably not strictly necessary, but play it safe.  */
  bzero (s, sizeof *s);
995

996 997 998 999
  --total_free_strings;
  ++total_strings;
  ++strings_consed;
  consing_since_gc += sizeof *s;
1000

1001
  return s;
1002
}
Jim Blandy's avatar
Jim Blandy committed
1003 1004


1005 1006 1007 1008 1009
/* Set up Lisp_String S for holding NCHARS characters, NBYTES bytes,
   plus a NUL byte at the end.  Allocate an sdata structure for S, and
   set S->data to its `u.data' member.  Store a NUL byte at the end of
   S->data.  Set S->size to NCHARS and S->size_byte to NBYTES.  Free
   S->data if it was initially non-null.  */
Jim Blandy's avatar
Jim Blandy committed
1010

1011 1012 1013 1014
void
allocate_string_data (s, nchars, nbytes)
     struct Lisp_String *s;
     int nchars, nbytes;
Jim Blandy's avatar
Jim Blandy committed
1015
{
1016 1017 1018
  struct sdata *data;
  struct sblock *b;
  int needed;
Jim Blandy's avatar
Jim Blandy committed
1019

1020 1021 1022
  /* Determine the number of bytes needed to store NBYTES bytes
     of string data.  */
  needed = SDATA_SIZE (nbytes);
Jim Blandy's avatar
Jim Blandy committed
1023