src/runtime/purify.c

   1 /*
   2  * C-level stuff to implement Lisp-level PURIFY
   3  */
   4
   5 /*
   6  * This software is part of the SBCL system. See the README file for
   7  * more information.
   8  *
   9  * This software is derived from the CMU CL system, which was
  10  * written at Carnegie Mellon University and released into the
  11  * public domain. The software is in the public domain and is
  12  * provided with absolutely no warranty. See the COPYING and CREDITS
  13  * files for more information.
  14  */
  15
  16 #include <stdio.h>
  17 #include <sys/types.h>
  18 #include <stdlib.h>
  19 #include <strings.h>
  20 #include <errno.h>
  21
  22 #include "sbcl.h"
  23 #include "runtime.h"
  24 #include "os.h"
  25 #include "globals.h"
  26 #include "validate.h"
  27 #include "interrupt.h"
  28 #include "purify.h"
  29 #include "interr.h"
  30 #include "gc.h"
  31 #include "gc-internal.h"
  32 #include "thread.h"
  33 #include "genesis/primitive-objects.h"
  34 #include "genesis/static-symbols.h"
  35 #include "genesis/layout.h"
  36 #include "genesis/hash-table.h"
  37 #include "gencgc.h"
  38
  39 /* We don't ever do purification with GENCGC as of 1.0.5.*. There was
  40  * a lot of hairy and fragile ifdeffage in here to support purify on
  41  * x86oids, which has now been removed. So this code can't even be
  42  * compiled with GENCGC any more.  -- JES, 2007-04-30.
  43  */
  44 #ifndef LISP_FEATURE_GENCGC
  45
  46 #define PRINTNOISE
  47
  48 static lispobj *dynamic_space_purify_pointer;
  49
  50 \f
  51 /* These hold the original end of the read_only and static spaces so
  52  * we can tell what are forwarding pointers. */
  53
  54 static lispobj *read_only_end, *static_end;
  55
  56 static lispobj *read_only_free, *static_free;
  57
  58 static lispobj *pscav(lispobj *addr, long nwords, boolean constant);
  59
  60 #define LATERBLOCKSIZE 1020
  61 #define LATERMAXCOUNT 10
  62
  63 static struct
  64 later {
  65     struct later *next;
  66     union {
  67         lispobj *ptr;
  68         long count;
  69     } u[LATERBLOCKSIZE];
  70 } *later_blocks = NULL;
  71 static long later_count = 0;
  72
  73 #if N_WORD_BITS == 32
  74  #define SIMPLE_ARRAY_WORD_WIDETAG SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG
  75 #elif N_WORD_BITS == 64
  76  #define SIMPLE_ARRAY_WORD_WIDETAG SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
  77 #endif
  78
  79 \f
  80 static boolean
  81 forwarding_pointer_p(lispobj obj)
  82 {
  83     lispobj *ptr = native_pointer(obj);
  84
  85     return ((static_end <= ptr && ptr <= static_free) ||
  86             (read_only_end <= ptr && ptr <= read_only_free));
  87 }
  88
  89 static boolean
  90 dynamic_pointer_p(lispobj ptr)
  91 {
  92     return (ptr >= (lispobj)current_dynamic_space
  93             &&
  94             ptr < (lispobj)dynamic_space_purify_pointer);
  95 }
  96
  97 static inline lispobj *
  98 newspace_alloc(long nwords, int constantp)
  99 {
 100     lispobj *ret;
 101     nwords=CEILING(nwords,2);
 102     if(constantp) {
 103         if(read_only_free + nwords >= (lispobj *)READ_ONLY_SPACE_END) {
 104             lose("Ran out of read-only space while purifying!\n");
 105         }
 106         ret=read_only_free;
 107         read_only_free+=nwords;
 108     } else {
 109         if(static_free + nwords >= (lispobj *)STATIC_SPACE_END) {
 110             lose("Ran out of static space while purifying!\n");
 111         }
 112         ret=static_free;
 113         static_free+=nwords;
 114     }
 115     return ret;
 116 }
 117
 118 \f
 119 static void
 120 pscav_later(lispobj *where, long count)
 121 {
 122     struct later *new;
 123
 124     if (count > LATERMAXCOUNT) {
 125         while (count > LATERMAXCOUNT) {
 126             pscav_later(where, LATERMAXCOUNT);
 127             count -= LATERMAXCOUNT;
 128             where += LATERMAXCOUNT;
 129         }
 130     }
 131     else {
 132         if (later_blocks == NULL || later_count == LATERBLOCKSIZE ||
 133             (later_count == LATERBLOCKSIZE-1 && count > 1)) {
 134             new  = (struct later *)malloc(sizeof(struct later));
 135             new->next = later_blocks;
 136             if (later_blocks && later_count < LATERBLOCKSIZE)
 137                 later_blocks->u[later_count].ptr = NULL;
 138             later_blocks = new;
 139             later_count = 0;
 140         }
 141
 142         if (count != 1)
 143             later_blocks->u[later_count++].count = count;
 144         later_blocks->u[later_count++].ptr = where;
 145     }
 146 }
 147
 148 static lispobj
 149 ptrans_boxed(lispobj thing, lispobj header, boolean constant)
 150 {
 151     long nwords;
 152     lispobj result, *new, *old;
 153
 154     nwords = CEILING(1 + HeaderValue(header), 2);
 155
 156     /* Allocate it */
 157     old = (lispobj *)native_pointer(thing);
 158     new = newspace_alloc(nwords,constant);
 159
 160     /* Copy it. */
 161     bcopy(old, new, nwords * sizeof(lispobj));
 162
 163     /* Deposit forwarding pointer. */
 164     result = make_lispobj(new, lowtag_of(thing));
 165     *old = result;
 166
 167     /* Scavenge it. */
 168     pscav(new, nwords, constant);
 169
 170     return result;
 171 }
 172
 173 /* We need to look at the layout to see whether it is a pure structure
 174  * class, and only then can we transport as constant. If it is pure,
 175  * we can ALWAYS transport as a constant. */
 176 static lispobj
 177 ptrans_instance(lispobj thing, lispobj header, boolean /* ignored */ constant)
 178 {
 179     struct layout *layout =
 180       (struct layout *) native_pointer(((struct instance *)native_pointer(thing))->slots[0]);
 181     lispobj pure = layout->pure;
 182
 183     switch (pure) {
 184     case T:
 185         return (ptrans_boxed(thing, header, 1));
 186     case NIL:
 187         return (ptrans_boxed(thing, header, 0));
 188     default:
 189         gc_abort();
 190         return NIL; /* dummy value: return something ... */
 191     }
 192 }
 193
 194 static lispobj
 195 ptrans_fdefn(lispobj thing, lispobj header)
 196 {
 197     long nwords;
 198     lispobj result, *new, *old, oldfn;
 199     struct fdefn *fdefn;
 200
 201     nwords = CEILING(1 + HeaderValue(header), 2);
 202
 203     /* Allocate it */
 204     old = (lispobj *)native_pointer(thing);
 205     new = newspace_alloc(nwords, 0);    /* inconstant */
 206
 207     /* Copy it. */
 208     bcopy(old, new, nwords * sizeof(lispobj));
 209
 210     /* Deposit forwarding pointer. */
 211     result = make_lispobj(new, lowtag_of(thing));
 212     *old = result;
 213
 214     /* Scavenge the function. */
 215     fdefn = (struct fdefn *)new;
 216     oldfn = fdefn->fun;
 217     pscav(&fdefn->fun, 1, 0);
 218     if ((char *)oldfn + FUN_RAW_ADDR_OFFSET == fdefn->raw_addr)
 219         fdefn->raw_addr = (char *)fdefn->fun + FUN_RAW_ADDR_OFFSET;
 220
 221     return result;
 222 }
 223
 224 static lispobj
 225 ptrans_unboxed(lispobj thing, lispobj header)
 226 {
 227     long nwords;
 228     lispobj result, *new, *old;
 229
 230     nwords = CEILING(1 + HeaderValue(header), 2);
 231
 232     /* Allocate it */
 233     old = (lispobj *)native_pointer(thing);
 234     new = newspace_alloc(nwords,1);     /* always constant */
 235
 236     /* copy it. */
 237     bcopy(old, new, nwords * sizeof(lispobj));
 238
 239     /* Deposit forwarding pointer. */
 240     result = make_lispobj(new , lowtag_of(thing));
 241     *old = result;
 242
 243     return result;
 244 }
 245
 246 static lispobj
 247 ptrans_vector(lispobj thing, long bits, long extra,
 248               boolean boxed, boolean constant)
 249 {
 250     struct vector *vector;
 251     long nwords;
 252     lispobj result, *new;
 253     long length;
 254
 255     vector = (struct vector *)native_pointer(thing);
 256     length = fixnum_value(vector->length)+extra;
 257     // Argh, handle simple-vector-nil separately.
 258     if (bits == 0) {
 259       nwords = 2;
 260     } else {
 261       nwords = CEILING(NWORDS(length, bits) + 2, 2);
 262     }
 263
 264     new=newspace_alloc(nwords, (constant || !boxed));
 265     bcopy(vector, new, nwords * sizeof(lispobj));
 266
 267     result = make_lispobj(new, lowtag_of(thing));
 268     vector->header = result;
 269
 270     if (boxed)
 271         pscav(new, nwords, constant);
 272
 273     return result;
 274 }
 275
 276 static lispobj
 277 ptrans_code(lispobj thing)
 278 {
 279     struct code *code = (struct code *)native_pointer(thing);
 280     long nwords = code_header_words(code->header)
 281                 + code_instruction_words(code->code_size);
 282
 283     struct code *new = (struct code *)newspace_alloc(nwords,1); /* constant */
 284
 285     bcopy(code, new, nwords * sizeof(lispobj));
 286
 287     lispobj result = make_lispobj(new, OTHER_POINTER_LOWTAG);
 288
 289     /* Put in forwarding pointers for all the functions. */
 290     for_each_simple_fun(func, code,
 291         *func = make_lispobj(code_fun_addr(new, index), FUN_POINTER_LOWTAG));
 292
 293     /* Stick in a forwarding pointer for the code object. */
 294     /* This smashes the header, so do it only after reading n_funs */
 295     *(lispobj *)code = result;
 296
 297     /* Arrange to scavenge the debug info later. */
 298     pscav_later(&new->debug_info, 1);
 299
 300     /* Scavenge the constants. */
 301     pscav(new->constants,
 302           code_header_words(new->header) - (offsetof(struct code, constants) >> WORD_SHIFT),
 303           1);
 304
 305     /* Scavenge all the functions. */
 306     for_each_simple_fun(func, new, {
 307         gc_assert(!dynamic_pointer_p((lispobj)func));
 308         pscav(&func->self, 1, 1);
 309         pscav_later(&func->name, 4);
 310     })
 311
 312     return result;
 313 }
 314
 315 static lispobj
 316 ptrans_func(lispobj thing, lispobj header)
 317 {
 318     long nwords;
 319     lispobj code, *new, *old, result;
 320     struct simple_fun *function;
 321
 322     /* Thing can either be a function header, a closure function
 323      * header, a closure, or a funcallable-instance. If it's a closure
 324      * or a funcallable-instance, we do the same as ptrans_boxed.
 325      * Otherwise we have to do something strange, 'cause it is buried
 326      * inside a code object. */
 327
 328     if (widetag_of(header) == SIMPLE_FUN_HEADER_WIDETAG) {
 329
 330         /* We can only end up here if the code object has not been
 331          * scavenged, because if it had been scavenged, forwarding pointers
 332          * would have been left behind for all the entry points. */
 333
 334         function = (struct simple_fun *)native_pointer(thing);
 335         code =
 336             make_lispobj
 337             ((native_pointer(thing) -
 338               (HeaderValue(function->header))), OTHER_POINTER_LOWTAG);
 339
 340         /* This will cause the function's header to be replaced with a
 341          * forwarding pointer. */
 342
 343         ptrans_code(code);
 344
 345         /* So we can just return that. */
 346         return function->header;
 347     }
 348     else {
 349         /* It's some kind of closure-like thing. */
 350         nwords = CEILING(1 + HeaderValue(header), 2);
 351         old = (lispobj *)native_pointer(thing);
 352
 353         /* Allocate the new one.  FINs *must* not go in read_only
 354          * space.  Closures can; they never change */
 355
 356         new = newspace_alloc
 357             (nwords,(widetag_of(header)!=FUNCALLABLE_INSTANCE_HEADER_WIDETAG));
 358
 359         /* Copy it. */
 360         bcopy(old, new, nwords * sizeof(lispobj));
 361
 362         /* Deposit forwarding pointer. */
 363         result = make_lispobj(new, lowtag_of(thing));
 364         *old = result;
 365
 366         /* Scavenge it. */
 367         pscav(new, nwords, 0);
 368
 369         return result;
 370     }
 371 }
 372
 373 static lispobj
 374 ptrans_returnpc(lispobj thing, lispobj header)
 375 {
 376     lispobj code, new;
 377
 378     /* Find the corresponding code object. */
 379     code = thing - HeaderValue(header)*sizeof(lispobj);
 380
 381     /* Make sure it's been transported. */
 382     new = *(lispobj *)native_pointer(code);
 383     if (!forwarding_pointer_p(new))
 384         new = ptrans_code(code);
 385
 386     /* Maintain the offset: */
 387     return new + (thing - code);
 388 }
 389
 390 #define WORDS_PER_CONS CEILING(sizeof(struct cons) / sizeof(lispobj), 2)
 391
 392 static lispobj
 393 ptrans_list(lispobj thing, boolean constant)
 394 {
 395     struct cons *old, *new, *orig;
 396     long length;
 397
 398     orig = (struct cons *) newspace_alloc(0,constant);
 399     length = 0;
 400
 401     do {
 402         /* Allocate a new cons cell. */
 403         old = (struct cons *)native_pointer(thing);
 404         new = (struct cons *) newspace_alloc(WORDS_PER_CONS,constant);
 405
 406         /* Copy the cons cell and keep a pointer to the cdr. */
 407         new->car = old->car;
 408         thing = new->cdr = old->cdr;
 409
 410         /* Set up the forwarding pointer. */
 411         *(lispobj *)old = make_lispobj(new, LIST_POINTER_LOWTAG);
 412
 413         /* And count this cell. */
 414         length++;
 415     } while (lowtag_of(thing) == LIST_POINTER_LOWTAG &&
 416              dynamic_pointer_p(thing) &&
 417              !(forwarding_pointer_p(*(lispobj *)native_pointer(thing))));
 418
 419     /* Scavenge the list we just copied. */
 420     pscav((lispobj *)orig, length * WORDS_PER_CONS, constant);
 421
 422     return make_lispobj(orig, LIST_POINTER_LOWTAG);
 423 }
 424
 425 static lispobj
 426 ptrans_otherptr(lispobj thing, lispobj header, boolean constant)
 427 {
 428     switch (widetag_of(header)) {
 429         /* FIXME: this needs a reindent */
 430       case BIGNUM_WIDETAG:
 431       case SINGLE_FLOAT_WIDETAG:
 432       case DOUBLE_FLOAT_WIDETAG:
 433 #ifdef LONG_FLOAT_WIDETAG
 434       case LONG_FLOAT_WIDETAG:
 435 #endif
 436 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
 437       case COMPLEX_SINGLE_FLOAT_WIDETAG:
 438 #endif
 439 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
 440       case COMPLEX_DOUBLE_FLOAT_WIDETAG:
 441 #endif
 442 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
 443       case COMPLEX_LONG_FLOAT_WIDETAG:
 444 #endif
 445       case SAP_WIDETAG:
 446           return ptrans_unboxed(thing, header);
 447       case RATIO_WIDETAG:
 448       case COMPLEX_WIDETAG:
 449       case SIMPLE_ARRAY_WIDETAG:
 450       case COMPLEX_BASE_STRING_WIDETAG:
 451 #ifdef COMPLEX_CHARACTER_STRING_WIDETAG
 452     case COMPLEX_CHARACTER_STRING_WIDETAG:
 453 #endif
 454       case COMPLEX_BIT_VECTOR_WIDETAG:
 455       case COMPLEX_VECTOR_NIL_WIDETAG:
 456       case COMPLEX_VECTOR_WIDETAG:
 457       case COMPLEX_ARRAY_WIDETAG:
 458         return ptrans_boxed(thing, header, constant);
 459
 460       case VALUE_CELL_HEADER_WIDETAG:
 461       case WEAK_POINTER_WIDETAG:
 462         return ptrans_boxed(thing, header, 0);
 463
 464       case SYMBOL_HEADER_WIDETAG:
 465         return ptrans_boxed(thing, header, 0);
 466
 467       case SIMPLE_ARRAY_NIL_WIDETAG:
 468         return ptrans_vector(thing, 0, 0, 0, constant);
 469
 470       case SIMPLE_BASE_STRING_WIDETAG:
 471         return ptrans_vector(thing, 8, 1, 0, constant);
 472
 473 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
 474     case SIMPLE_CHARACTER_STRING_WIDETAG:
 475         return ptrans_vector(thing, 32, 1, 0, constant);
 476 #endif
 477
 478       case SIMPLE_BIT_VECTOR_WIDETAG:
 479         return ptrans_vector(thing, 1, 0, 0, constant);
 480
 481       case SIMPLE_VECTOR_WIDETAG:
 482         return ptrans_vector(thing, N_WORD_BITS, 0, 1, constant);
 483
 484       case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
 485         return ptrans_vector(thing, 2, 0, 0, constant);
 486
 487       case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
 488         return ptrans_vector(thing, 4, 0, 0, constant);
 489
 490       case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
 491 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
 492       case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
 493       case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
 494 #endif
 495         return ptrans_vector(thing, 8, 0, 0, constant);
 496
 497       case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
 498 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
 499       case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
 500       case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
 501 #endif
 502         return ptrans_vector(thing, 16, 0, 0, constant);
 503
 504       case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
 505       case SIMPLE_ARRAY_FIXNUM_WIDETAG:
 506       case SIMPLE_ARRAY_UNSIGNED_FIXNUM_WIDETAG:
 507 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
 508       case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
 509       case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
 510 #endif
 511         return ptrans_vector(thing, 32, 0, 0, constant);
 512
 513 #if N_WORD_BITS == 64
 514 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
 515       case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
 516 #endif
 517 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
 518       case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
 519 #endif
 520 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
 521       case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
 522 #endif
 523         return ptrans_vector(thing, 64, 0, 0, constant);
 524 #endif
 525
 526       case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
 527         return ptrans_vector(thing, 32, 0, 0, constant);
 528
 529       case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
 530         return ptrans_vector(thing, 64, 0, 0, constant);
 531
 532 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
 533       case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
 534 #ifdef LISP_FEATURE_SPARC
 535         return ptrans_vector(thing, 128, 0, 0, constant);
 536 #endif
 537 #endif
 538
 539 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
 540       case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
 541         return ptrans_vector(thing, 64, 0, 0, constant);
 542 #endif
 543
 544 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
 545       case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
 546         return ptrans_vector(thing, 128, 0, 0, constant);
 547 #endif
 548
 549 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
 550       case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
 551 #ifdef LISP_FEATURE_SPARC
 552         return ptrans_vector(thing, 256, 0, 0, constant);
 553 #endif
 554 #endif
 555
 556       case CODE_HEADER_WIDETAG:
 557         return ptrans_code(thing);
 558
 559       case RETURN_PC_HEADER_WIDETAG:
 560         return ptrans_returnpc(thing, header);
 561
 562       case FDEFN_WIDETAG:
 563         return ptrans_fdefn(thing, header);
 564
 565       default:
 566         fprintf(stderr, "Invalid widetag: %d\n", widetag_of(header));
 567         /* Should only come across other pointers to the above stuff. */
 568         gc_abort();
 569         return NIL;
 570     }
 571 }
 572
 573 static long
 574 pscav_fdefn(struct fdefn *fdefn)
 575 {
 576     boolean fix_func;
 577
 578     fix_func = ((char *)(fdefn->fun+FUN_RAW_ADDR_OFFSET) == fdefn->raw_addr);
 579     pscav(&fdefn->name, 1, 1);
 580     pscav(&fdefn->fun, 1, 0);
 581     if (fix_func)
 582         fdefn->raw_addr = (char *)(fdefn->fun + FUN_RAW_ADDR_OFFSET);
 583     return sizeof(struct fdefn) / sizeof(lispobj);
 584 }
 585
 586 static lispobj *
 587 pscav(lispobj *addr, long nwords, boolean constant)
 588 {
 589     lispobj thing, *thingp, header;
 590     long count = 0; /* (0 = dummy init value to stop GCC warning) */
 591     struct vector *vector;
 592
 593     while (nwords > 0) {
 594         thing = *addr;
 595         if (is_lisp_pointer(thing)) {
 596             /* It's a pointer. Is it something we might have to move? */
 597             if (dynamic_pointer_p(thing)) {
 598                 /* Maybe. Have we already moved it? */
 599                 thingp = (lispobj *)native_pointer(thing);
 600                 header = *thingp;
 601                 if (is_lisp_pointer(header) && forwarding_pointer_p(header))
 602                     /* Yep, so just copy the forwarding pointer. */
 603                     thing = header;
 604                 else {
 605                     /* Nope, copy the object. */
 606                     switch (lowtag_of(thing)) {
 607                       case FUN_POINTER_LOWTAG:
 608                         thing = ptrans_func(thing, header);
 609                         break;
 610
 611                       case LIST_POINTER_LOWTAG:
 612                         thing = ptrans_list(thing, constant);
 613                         break;
 614
 615                       case INSTANCE_POINTER_LOWTAG:
 616                         thing = ptrans_instance(thing, header, constant);
 617                         break;
 618
 619                       case OTHER_POINTER_LOWTAG:
 620                         thing = ptrans_otherptr(thing, header, constant);
 621                         break;
 622
 623                       default:
 624                         /* It was a pointer, but not one of them? */
 625                         gc_abort();
 626                     }
 627                 }
 628                 *addr = thing;
 629             }
 630             count = 1;
 631         }
 632 #if N_WORD_BITS == 64
 633         else if (widetag_of(thing) == SINGLE_FLOAT_WIDETAG) {
 634             count = 1;
 635         }
 636 #endif
 637         else if (thing & FIXNUM_TAG_MASK) {
 638             /* It's an other immediate. Maybe the header for an unboxed */
 639             /* object. */
 640             switch (widetag_of(thing)) {
 641               case BIGNUM_WIDETAG:
 642               case SINGLE_FLOAT_WIDETAG:
 643               case DOUBLE_FLOAT_WIDETAG:
 644 #ifdef LONG_FLOAT_WIDETAG
 645               case LONG_FLOAT_WIDETAG:
 646 #endif
 647               case SAP_WIDETAG:
 648                 /* It's an unboxed simple object. */
 649                 count = CEILING(HeaderValue(thing)+1, 2);
 650                 break;
 651
 652               case SIMPLE_VECTOR_WIDETAG:
 653                   if (HeaderValue(thing) == subtype_VectorValidHashing) {
 654                     struct hash_table *hash_table =
 655                         (struct hash_table *)native_pointer(addr[2]);
 656                     hash_table->needs_rehash_p = T;
 657                   }
 658                 count = 2;
 659                 break;
 660
 661               case SIMPLE_ARRAY_NIL_WIDETAG:
 662                 count = 2;
 663                 break;
 664
 665               case SIMPLE_BASE_STRING_WIDETAG:
 666                 vector = (struct vector *)addr;
 667                 count = CEILING(NWORDS(fixnum_value(vector->length)+1,8)+2,2);
 668                 break;
 669
 670 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
 671             case SIMPLE_CHARACTER_STRING_WIDETAG:
 672                 vector = (struct vector *)addr;
 673                 count = CEILING(NWORDS(fixnum_value(vector->length)+1,32)+2,2);
 674                 break;
 675 #endif
 676
 677               case SIMPLE_BIT_VECTOR_WIDETAG:
 678                 vector = (struct vector *)addr;
 679                 count = CEILING(NWORDS(fixnum_value(vector->length),1)+2,2);
 680                 break;
 681
 682               case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
 683                 vector = (struct vector *)addr;
 684                 count = CEILING(NWORDS(fixnum_value(vector->length),2)+2,2);
 685                 break;
 686
 687               case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
 688                 vector = (struct vector *)addr;
 689                 count = CEILING(NWORDS(fixnum_value(vector->length),4)+2,2);
 690                 break;
 691
 692               case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
 693 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
 694               case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
 695               case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
 696 #endif
 697                 vector = (struct vector *)addr;
 698                 count = CEILING(NWORDS(fixnum_value(vector->length),8)+2,2);
 699                 break;
 700
 701               case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
 702 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
 703               case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
 704               case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
 705 #endif
 706                 vector = (struct vector *)addr;
 707                 count = CEILING(NWORDS(fixnum_value(vector->length),16)+2,2);
 708                 break;
 709
 710               case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
 711
 712               case SIMPLE_ARRAY_FIXNUM_WIDETAG:
 713               case SIMPLE_ARRAY_UNSIGNED_FIXNUM_WIDETAG:
 714
 715 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
 716               case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
 717               case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
 718 #endif
 719                 vector = (struct vector *)addr;
 720                 count = CEILING(NWORDS(fixnum_value(vector->length),32)+2,2);
 721                 break;
 722
 723 #if N_WORD_BITS == 64
 724               case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
 725 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
 726               case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
 727               case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
 728 #endif
 729                 vector = (struct vector *)addr;
 730                 count = CEILING(NWORDS(fixnum_value(vector->length),64)+2,2);
 731                 break;
 732 #endif
 733
 734               case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
 735                 vector = (struct vector *)addr;
 736                 count = CEILING(NWORDS(fixnum_value(vector->length), 32) + 2,
 737                                 2);
 738                 break;
 739
 740               case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
 741 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
 742               case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
 743 #endif
 744                 vector = (struct vector *)addr;
 745                 count = CEILING(NWORDS(fixnum_value(vector->length), 64) + 2,
 746                                 2);
 747                 break;
 748
 749 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
 750               case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
 751                 vector = (struct vector *)addr;
 752 #ifdef LISP_FEATURE_SPARC
 753                 count = fixnum_value(vector->length)*4+2;
 754 #endif
 755                 break;
 756 #endif
 757
 758 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
 759               case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
 760                 vector = (struct vector *)addr;
 761                 count = CEILING(NWORDS(fixnum_value(vector->length), 128) + 2,
 762                                 2);
 763                 break;
 764 #endif
 765
 766 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
 767               case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
 768                 vector = (struct vector *)addr;
 769 #ifdef LISP_FEATURE_SPARC
 770                 count = fixnum_value(vector->length)*8+2;
 771 #endif
 772                 break;
 773 #endif
 774
 775               case CODE_HEADER_WIDETAG:
 776                 gc_abort(); /* no code headers in static space */
 777                 break;
 778
 779               case SIMPLE_FUN_HEADER_WIDETAG:
 780               case RETURN_PC_HEADER_WIDETAG:
 781                 /* We should never hit any of these, 'cause they occur
 782                  * buried in the middle of code objects. */
 783                 gc_abort();
 784                 break;
 785
 786               case WEAK_POINTER_WIDETAG:
 787                 /* Weak pointers get preserved during purify, 'cause I
 788                  * don't feel like figuring out how to break them. */
 789                 pscav(addr+1, 2, constant);
 790                 count = 4;
 791                 break;
 792
 793               case FDEFN_WIDETAG:
 794                 /* We have to handle fdefn objects specially, so we
 795                  * can fix up the raw function address. */
 796                 count = pscav_fdefn((struct fdefn *)addr);
 797                 break;
 798
 799               case INSTANCE_HEADER_WIDETAG:
 800                 {
 801                     struct instance *instance = (struct instance *) addr;
 802                     struct layout *layout
 803                         = (struct layout *) native_pointer(instance->slots[0]);
 804                     long nslots = HeaderValue(*addr);
 805                     int index;
 806                     if (fixnump(layout->bitmap)) {
 807                       sword_t bitmap = (sword_t)layout->bitmap >> N_FIXNUM_TAG_BITS;
 808                       for (index = 0; index < nslots ; index++, bitmap >>= 1)
 809                         if (bitmap & 1)
 810                           pscav(addr + 1 + index, 1, constant);
 811                     } else {
 812                       struct bignum * bitmap;
 813                       bitmap = (struct bignum*)native_pointer(layout->bitmap);
 814                       for (index = 0; index < nslots ; index++)
 815                         if (positive_bignum_logbitp(index, bitmap))
 816                           pscav(addr + 1 + index, 1, constant);
 817                     }
 818                     count = CEILING(1 + nslots, 2);
 819                 }
 820                 break;
 821
 822               default:
 823                 count = 1;
 824                 break;
 825             }
 826         }
 827         else {
 828             /* It's a fixnum. */
 829             count = 1;
 830         }
 831
 832         addr += count;
 833         nwords -= count;
 834     }
 835
 836     return addr;
 837 }
 838
 839 int
 840 purify(lispobj static_roots, lispobj read_only_roots)
 841 {
 842     lispobj *clean;
 843     long count, i;
 844     struct later *laters, *next;
 845     struct thread *thread;
 846
 847     if(all_threads->next) {
 848         /* FIXME: there should be _some_ sensible error reporting
 849          * convention.  See following comment too */
 850         fprintf(stderr,"Can't purify when more than one thread exists\n");
 851         fflush(stderr);
 852         return 0;
 853     }
 854
 855 #ifdef PRINTNOISE
 856     printf("[doing purification:");
 857     fflush(stdout);
 858 #endif
 859
 860     for_each_thread(thread)
 861         if (fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread)) != 0) {
 862         /* FIXME: 1. What does this mean? 2. It shouldn't be reporting
 863          * its error simply by a. printing a string b. to stdout instead
 864          * of stderr. */
 865         printf(" Ack! Can't purify interrupt contexts. ");
 866         fflush(stdout);
 867         return 0;
 868     }
 869
 870     dynamic_space_purify_pointer = dynamic_space_free_pointer;
 871
 872     read_only_end = read_only_free =
 873         (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
 874     static_end = static_free =
 875         (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
 876
 877 #ifdef PRINTNOISE
 878     printf(" roots");
 879     fflush(stdout);
 880 #endif
 881
 882     pscav(&static_roots, 1, 0);
 883     pscav(&read_only_roots, 1, 1);
 884
 885 #ifdef PRINTNOISE
 886     printf(" handlers");
 887     fflush(stdout);
 888 #endif
 889     pscav((lispobj *) interrupt_handlers,
 890           sizeof(interrupt_handlers) / sizeof(lispobj),
 891           0);
 892
 893 #ifdef PRINTNOISE
 894     printf(" stack");
 895     fflush(stdout);
 896 #endif
 897     pscav((lispobj *)all_threads->control_stack_start,
 898           access_control_stack_pointer(all_threads) -
 899           all_threads->control_stack_start,
 900           0);
 901
 902 #ifdef PRINTNOISE
 903     printf(" bindings");
 904     fflush(stdout);
 905 #endif
 906
 907     pscav( (lispobj *)all_threads->binding_stack_start,
 908            (lispobj *)get_binding_stack_pointer(all_threads) -
 909            all_threads->binding_stack_start,
 910           0);
 911
 912     /* The original CMU CL code had scavenge-read-only-space code
 913      * controlled by the Lisp-level variable
 914      * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
 915      * wasn't documented under what circumstances it was useful or
 916      * safe to turn it on, so it's been turned off in SBCL. If you
 917      * want/need this functionality, and can test and document it,
 918      * please submit a patch. */
 919 #if 0
 920     if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != UNBOUND_MARKER_WIDETAG
 921         && SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
 922       unsigned  read_only_space_size =
 923           (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
 924           (lispobj *)READ_ONLY_SPACE_START;
 925       fprintf(stderr,
 926               "scavenging read only space: %d bytes\n",
 927               read_only_space_size * sizeof(lispobj));
 928       pscav( (lispobj *)READ_ONLY_SPACE_START, read_only_space_size, 0);
 929     }
 930 #endif
 931
 932 #ifdef PRINTNOISE
 933     printf(" static");
 934     fflush(stdout);
 935 #endif
 936     clean = (lispobj *)STATIC_SPACE_START;
 937     do {
 938         while (clean != static_free)
 939             clean = pscav(clean, static_free - clean, 0);
 940         laters = later_blocks;
 941         count = later_count;
 942         later_blocks = NULL;
 943         later_count = 0;
 944         while (laters != NULL) {
 945             for (i = 0; i < count; i++) {
 946                 if (laters->u[i].count == 0) {
 947                     ;
 948                 } else if (laters->u[i].count <= LATERMAXCOUNT) {
 949                     pscav(laters->u[i+1].ptr, laters->u[i].count, 1);
 950                     i++;
 951                 } else {
 952                     pscav(laters->u[i].ptr, 1, 1);
 953                 }
 954             }
 955             next = laters->next;
 956             free(laters);
 957             laters = next;
 958             count = LATERBLOCKSIZE;
 959         }
 960     } while (clean != static_free || later_blocks != NULL);
 961
 962 #ifdef PRINTNOISE
 963     printf(" cleanup");
 964     fflush(stdout);
 965 #endif
 966 #ifdef LISP_FEATURE_HPUX
 967     clear_auto_gc_trigger(); /* restore mmap as it was given by os */
 968 #endif
 969
 970     os_zero((os_vm_address_t) current_dynamic_space, dynamic_space_size);
 971
 972     /* Zero the stack. */
 973     os_zero((os_vm_address_t) access_control_stack_pointer(all_threads),
 974             (os_vm_size_t)
 975             ((all_threads->control_stack_end -
 976               access_control_stack_pointer(all_threads)) * sizeof(lispobj)));
 977
 978     /* It helps to update the heap free pointers so that free_heap can
 979      * verify after it's done. */
 980     SetSymbolValue(READ_ONLY_SPACE_FREE_POINTER, (lispobj)read_only_free,0);
 981     SetSymbolValue(STATIC_SPACE_FREE_POINTER, (lispobj)static_free,0);
 982
 983     dynamic_space_free_pointer = current_dynamic_space;
 984     set_auto_gc_trigger(bytes_consed_between_gcs);
 985
 986     /* Blast away instruction cache */
 987     os_flush_icache((os_vm_address_t)READ_ONLY_SPACE_START, READ_ONLY_SPACE_SIZE);
 988     os_flush_icache((os_vm_address_t)STATIC_SPACE_START, STATIC_SPACE_SIZE);
 989
 990 #ifdef PRINTNOISE
 991     printf(" done]\n");
 992     fflush(stdout);
 993 #endif
 994     return 0;
 995 }
 996 #else /* LISP_FEATURE_GENCGC */
 997 int
 998 purify(lispobj static_roots, lispobj read_only_roots)
 999 {
1000     lose("purify called for GENCGC. This should not happen.");
1001 }
1002 #endif /* LISP_FEATURE_GENCGC */