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
  36 #define PRINTNOISE
  37
  38 #if defined(LISP_FEATURE_X86)
  39 /* again, what's so special about the x86 that this is differently
  40  * visible there than on other platforms? -dan 20010125
  41  */
  42 static lispobj *dynamic_space_free_pointer;
  43 #endif
  44 extern unsigned long bytes_consed_between_gcs;
  45
  46 #define gc_abort() \
  47   lose("GC invariant lost, file \"%s\", line %d", __FILE__, __LINE__)
  48
  49 #if 1
  50 #define gc_assert(ex) do { \
  51         if (!(ex)) gc_abort(); \
  52 } while (0)
  53 #else
  54 #define gc_assert(ex)
  55 #endif
  56
  57 \f
  58 /* These hold the original end of the read_only and static spaces so
  59  * we can tell what are forwarding pointers. */
  60
  61 static lispobj *read_only_end, *static_end;
  62
  63 static lispobj *read_only_free, *static_free;
  64
  65 static lispobj *pscav(lispobj *addr, int nwords, boolean constant);
  66
  67 #define LATERBLOCKSIZE 1020
  68 #define LATERMAXCOUNT 10
  69
  70 static struct
  71 later {
  72     struct later *next;
  73     union {
  74         lispobj *ptr;
  75         int count;
  76     } u[LATERBLOCKSIZE];
  77 } *later_blocks = NULL;
  78 static int later_count = 0;
  79
  80 #define CEILING(x,y) (((x) + ((y) - 1)) & (~((y) - 1)))
  81 #define NWORDS(x,y) (CEILING((x),(y)) / (y))
  82
  83 /* FIXME: Shouldn't this be defined in sbcl.h?  See also notes in
  84  * cheneygc.c */
  85
  86 #ifdef sparc
  87 #define FUN_RAW_ADDR_OFFSET 0
  88 #else
  89 #define FUN_RAW_ADDR_OFFSET (6*sizeof(lispobj) - FUN_POINTER_LOWTAG)
  90 #endif
  91 \f
  92 static boolean
  93 forwarding_pointer_p(lispobj obj)
  94 {
  95     lispobj *ptr = native_pointer(obj);
  96
  97     return ((static_end <= ptr && ptr <= static_free) ||
  98             (read_only_end <= ptr && ptr <= read_only_free));
  99 }
 100
 101 static boolean
 102 dynamic_pointer_p(lispobj ptr)
 103 {
 104 #ifndef LISP_FEATURE_GENCGC
 105     return (ptr >= (lispobj)current_dynamic_space
 106             &&
 107             ptr < (lispobj)dynamic_space_free_pointer);
 108 #else
 109     /* Be more conservative, and remember, this is a maybe. */
 110     return (ptr >= (lispobj)DYNAMIC_SPACE_START
 111             &&
 112             ptr < (lispobj)dynamic_space_free_pointer);
 113 #endif
 114 }
 115
 116 static inline lispobj *
 117 newspace_alloc(int nwords, int constantp)
 118 {
 119     lispobj *ret;
 120     nwords=CEILING(nwords,2);
 121     if(constantp) {
 122         ret=read_only_free;
 123         read_only_free+=nwords;
 124     } else {
 125         ret=static_free;
 126         static_free+=nwords;
 127     }
 128     return ret;
 129 }
 130
 131
 132 \f
 133 #ifdef LISP_FEATURE_X86
 134
 135 #ifdef LISP_FEATURE_GENCGC
 136 /*
 137  * enhanced x86/GENCGC stack scavenging by Douglas Crosher
 138  *
 139  * Scavenging the stack on the i386 is problematic due to conservative
 140  * roots and raw return addresses. Here it is handled in two passes:
 141  * the first pass runs before any objects are moved and tries to
 142  * identify valid pointers and return address on the stack, the second
 143  * pass scavenges these.
 144  */
 145
 146 static unsigned pointer_filter_verbose = 0;
 147
 148 /* FIXME: This is substantially the same code as
 149  * possibly_valid_dynamic_space_pointer in gencgc.c.  The only
 150  * relevant difference seems to be that the gencgc code also checks
 151  * for raw pointers into Code objects, whereas in purify these are
 152  * checked separately in setup_i386_stack_scav - they go onto
 153  * valid_stack_ra_locations instead of just valid_stack_locations */
 154
 155 static int
 156 valid_dynamic_space_pointer(lispobj *pointer, lispobj *start_addr)
 157 {
 158     /* If it's not a return address then it needs to be a valid Lisp
 159      * pointer. */
 160     if (!is_lisp_pointer((lispobj)pointer))
 161         return 0;
 162
 163     /* Check that the object pointed to is consistent with the pointer
 164      * low tag. */
 165     switch (lowtag_of((lispobj)pointer)) {
 166     case FUN_POINTER_LOWTAG:
 167         /* Start_addr should be the enclosing code object, or a closure
 168          * header. */
 169         switch (widetag_of(*start_addr)) {
 170         case CODE_HEADER_WIDETAG:
 171             /* This case is probably caught above. */
 172             break;
 173         case CLOSURE_HEADER_WIDETAG:
 174         case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
 175             if ((int)pointer != ((int)start_addr+FUN_POINTER_LOWTAG)) {
 176                 if (pointer_filter_verbose) {
 177                     fprintf(stderr,"*Wf2: %x %x %x\n", (unsigned int) pointer,
 178                             (unsigned int) start_addr, *start_addr);
 179                 }
 180                 return 0;
 181             }
 182             break;
 183         default:
 184             if (pointer_filter_verbose) {
 185                 fprintf(stderr,"*Wf3: %x %x %x\n", (unsigned int) pointer,
 186                         (unsigned int) start_addr, *start_addr);
 187             }
 188             return 0;
 189         }
 190         break;
 191     case LIST_POINTER_LOWTAG:
 192         if ((int)pointer != ((int)start_addr+LIST_POINTER_LOWTAG)) {
 193             if (pointer_filter_verbose)
 194                 fprintf(stderr,"*Wl1: %x %x %x\n", (unsigned int) pointer,
 195                         (unsigned int) start_addr, *start_addr);
 196             return 0;
 197         }
 198         /* Is it plausible cons? */
 199         if ((is_lisp_pointer(start_addr[0])
 200             || ((start_addr[0] & 3) == 0) /* fixnum */
 201             || (widetag_of(start_addr[0]) == BASE_CHAR_WIDETAG)
 202             || (widetag_of(start_addr[0]) == UNBOUND_MARKER_WIDETAG))
 203            && (is_lisp_pointer(start_addr[1])
 204                || ((start_addr[1] & 3) == 0) /* fixnum */
 205                || (widetag_of(start_addr[1]) == BASE_CHAR_WIDETAG)
 206                || (widetag_of(start_addr[1]) == UNBOUND_MARKER_WIDETAG))) {
 207             break;
 208         } else {
 209             if (pointer_filter_verbose) {
 210                 fprintf(stderr,"*Wl2: %x %x %x\n", (unsigned int) pointer,
 211                         (unsigned int) start_addr, *start_addr);
 212             }
 213             return 0;
 214         }
 215     case INSTANCE_POINTER_LOWTAG:
 216         if ((int)pointer != ((int)start_addr+INSTANCE_POINTER_LOWTAG)) {
 217             if (pointer_filter_verbose) {
 218                 fprintf(stderr,"*Wi1: %x %x %x\n", (unsigned int) pointer,
 219                         (unsigned int) start_addr, *start_addr);
 220             }
 221             return 0;
 222         }
 223         if (widetag_of(start_addr[0]) != INSTANCE_HEADER_WIDETAG) {
 224             if (pointer_filter_verbose) {
 225                 fprintf(stderr,"*Wi2: %x %x %x\n", (unsigned int) pointer,
 226                         (unsigned int) start_addr, *start_addr);
 227             }
 228             return 0;
 229         }
 230         break;
 231     case OTHER_POINTER_LOWTAG:
 232         if ((int)pointer != ((int)start_addr+OTHER_POINTER_LOWTAG)) {
 233             if (pointer_filter_verbose) {
 234                 fprintf(stderr,"*Wo1: %x %x %x\n", (unsigned int) pointer,
 235                         (unsigned int) start_addr, *start_addr);
 236             }
 237             return 0;
 238         }
 239         /* Is it plausible? Not a cons. XXX should check the headers. */
 240         if (is_lisp_pointer(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
 241             if (pointer_filter_verbose) {
 242                 fprintf(stderr,"*Wo2: %x %x %x\n", (unsigned int) pointer,
 243                         (unsigned int) start_addr, *start_addr);
 244             }
 245             return 0;
 246         }
 247         switch (widetag_of(start_addr[0])) {
 248         case UNBOUND_MARKER_WIDETAG:
 249         case BASE_CHAR_WIDETAG:
 250             if (pointer_filter_verbose) {
 251                 fprintf(stderr,"*Wo3: %x %x %x\n", (unsigned int) pointer,
 252                         (unsigned int) start_addr, *start_addr);
 253             }
 254             return 0;
 255
 256             /* only pointed to by function pointers? */
 257         case CLOSURE_HEADER_WIDETAG:
 258         case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
 259             if (pointer_filter_verbose) {
 260                 fprintf(stderr,"*Wo4: %x %x %x\n", (unsigned int) pointer,
 261                         (unsigned int) start_addr, *start_addr);
 262             }
 263             return 0;
 264
 265         case INSTANCE_HEADER_WIDETAG:
 266             if (pointer_filter_verbose) {
 267                 fprintf(stderr,"*Wo5: %x %x %x\n", (unsigned int) pointer,
 268                         (unsigned int) start_addr, *start_addr);
 269             }
 270             return 0;
 271
 272             /* the valid other immediate pointer objects */
 273         case SIMPLE_VECTOR_WIDETAG:
 274         case RATIO_WIDETAG:
 275         case COMPLEX_WIDETAG:
 276 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
 277         case COMPLEX_SINGLE_FLOAT_WIDETAG:
 278 #endif
 279 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
 280         case COMPLEX_DOUBLE_FLOAT_WIDETAG:
 281 #endif
 282 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
 283         case COMPLEX_LONG_FLOAT_WIDETAG:
 284 #endif
 285         case SIMPLE_ARRAY_WIDETAG:
 286         case COMPLEX_BASE_STRING_WIDETAG:
 287         case COMPLEX_VECTOR_NIL_WIDETAG:
 288         case COMPLEX_BIT_VECTOR_WIDETAG:
 289         case COMPLEX_VECTOR_WIDETAG:
 290         case COMPLEX_ARRAY_WIDETAG:
 291         case VALUE_CELL_HEADER_WIDETAG:
 292         case SYMBOL_HEADER_WIDETAG:
 293         case FDEFN_WIDETAG:
 294         case CODE_HEADER_WIDETAG:
 295         case BIGNUM_WIDETAG:
 296         case SINGLE_FLOAT_WIDETAG:
 297         case DOUBLE_FLOAT_WIDETAG:
 298 #ifdef LONG_FLOAT_WIDETAG
 299         case LONG_FLOAT_WIDETAG:
 300 #endif
 301         case SIMPLE_ARRAY_NIL_WIDETAG:
 302         case SIMPLE_BASE_STRING_WIDETAG:
 303         case SIMPLE_BIT_VECTOR_WIDETAG:
 304         case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
 305         case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
 306         case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
 307         case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
 308         case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
 309         case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
 310         case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
 311         case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
 312         case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
 313 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
 314         case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
 315 #endif
 316 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
 317         case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
 318 #endif
 319 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
 320         case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
 321 #endif
 322 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
 323         case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
 324 #endif
 325         case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
 326         case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
 327 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
 328         case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
 329 #endif
 330 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
 331         case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
 332 #endif
 333 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
 334         case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
 335 #endif
 336 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
 337         case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
 338 #endif
 339         case SAP_WIDETAG:
 340         case WEAK_POINTER_WIDETAG:
 341             break;
 342
 343         default:
 344             if (pointer_filter_verbose) {
 345                 fprintf(stderr,"*Wo6: %x %x %x\n", (unsigned int) pointer,
 346                         (unsigned int) start_addr, *start_addr);
 347             }
 348             return 0;
 349         }
 350         break;
 351     default:
 352         if (pointer_filter_verbose) {
 353             fprintf(stderr,"*W?: %x %x %x\n", (unsigned int) pointer,
 354                     (unsigned int) start_addr, *start_addr);
 355         }
 356         return 0;
 357     }
 358
 359     /* looks good */
 360     return 1;
 361 }
 362
 363 #define MAX_STACK_POINTERS 256
 364 lispobj *valid_stack_locations[MAX_STACK_POINTERS];
 365 unsigned int num_valid_stack_locations;
 366
 367 #define MAX_STACK_RETURN_ADDRESSES 128
 368 lispobj *valid_stack_ra_locations[MAX_STACK_RETURN_ADDRESSES];
 369 lispobj *valid_stack_ra_code_objects[MAX_STACK_RETURN_ADDRESSES];
 370 unsigned int num_valid_stack_ra_locations;
 371
 372 /* Identify valid stack slots. */
 373 static void
 374 setup_i386_stack_scav(lispobj *lowaddr, lispobj *base)
 375 {
 376     lispobj *sp = lowaddr;
 377     num_valid_stack_locations = 0;
 378     num_valid_stack_ra_locations = 0;
 379     for (sp = lowaddr; sp < base; sp++) {
 380         lispobj thing = *sp;
 381         /* Find the object start address */
 382         lispobj *start_addr = search_dynamic_space((void *)thing);
 383         if (start_addr) {
 384             /* We need to allow raw pointers into Code objects for
 385              * return addresses. This will also pick up pointers to
 386              * functions in code objects. */
 387             if (widetag_of(*start_addr) == CODE_HEADER_WIDETAG) {
 388                 /* FIXME asserting here is a really dumb thing to do.
 389                  * If we've overflowed some arbitrary static limit, we
 390                  * should just refuse to purify, instead of killing
 391                  * the whole lisp session
 392                  */
 393                 gc_assert(num_valid_stack_ra_locations <
 394                           MAX_STACK_RETURN_ADDRESSES);
 395                 valid_stack_ra_locations[num_valid_stack_ra_locations] = sp;
 396                 valid_stack_ra_code_objects[num_valid_stack_ra_locations++] =
 397                     (lispobj *)((int)start_addr + OTHER_POINTER_LOWTAG);
 398             } else {
 399                 if (valid_dynamic_space_pointer((void *)thing, start_addr)) {
 400                     gc_assert(num_valid_stack_locations < MAX_STACK_POINTERS);
 401                     valid_stack_locations[num_valid_stack_locations++] = sp;
 402                 }
 403             }
 404         }
 405     }
 406     if (pointer_filter_verbose) {
 407         fprintf(stderr, "number of valid stack pointers = %d\n",
 408                 num_valid_stack_locations);
 409         fprintf(stderr, "number of stack return addresses = %d\n",
 410                 num_valid_stack_ra_locations);
 411     }
 412 }
 413
 414 static void
 415 pscav_i386_stack(void)
 416 {
 417     int i;
 418
 419     for (i = 0; i < num_valid_stack_locations; i++)
 420         pscav(valid_stack_locations[i], 1, 0);
 421
 422     for (i = 0; i < num_valid_stack_ra_locations; i++) {
 423         lispobj code_obj = (lispobj)valid_stack_ra_code_objects[i];
 424         pscav(&code_obj, 1, 0);
 425         if (pointer_filter_verbose) {
 426             fprintf(stderr,"*C moved RA %x to %x; for code object %x to %x\n",
 427                     *valid_stack_ra_locations[i],
 428                     (int)(*valid_stack_ra_locations[i])
 429                     - ((int)valid_stack_ra_code_objects[i] - (int)code_obj),
 430                     (unsigned int) valid_stack_ra_code_objects[i], code_obj);
 431         }
 432         *valid_stack_ra_locations[i] =
 433             ((int)(*valid_stack_ra_locations[i])
 434              - ((int)valid_stack_ra_code_objects[i] - (int)code_obj));
 435     }
 436 }
 437 #endif
 438 #endif
 439
 440 \f
 441 static void
 442 pscav_later(lispobj *where, int count)
 443 {
 444     struct later *new;
 445
 446     if (count > LATERMAXCOUNT) {
 447         while (count > LATERMAXCOUNT) {
 448             pscav_later(where, LATERMAXCOUNT);
 449             count -= LATERMAXCOUNT;
 450             where += LATERMAXCOUNT;
 451         }
 452     }
 453     else {
 454         if (later_blocks == NULL || later_count == LATERBLOCKSIZE ||
 455             (later_count == LATERBLOCKSIZE-1 && count > 1)) {
 456             new  = (struct later *)malloc(sizeof(struct later));
 457             new->next = later_blocks;
 458             if (later_blocks && later_count < LATERBLOCKSIZE)
 459                 later_blocks->u[later_count].ptr = NULL;
 460             later_blocks = new;
 461             later_count = 0;
 462         }
 463
 464         if (count != 1)
 465             later_blocks->u[later_count++].count = count;
 466         later_blocks->u[later_count++].ptr = where;
 467     }
 468 }
 469
 470 static lispobj
 471 ptrans_boxed(lispobj thing, lispobj header, boolean constant)
 472 {
 473     int nwords;
 474     lispobj result, *new, *old;
 475
 476     nwords = 1 + HeaderValue(header);
 477
 478     /* Allocate it */
 479     old = (lispobj *)native_pointer(thing);
 480     new = newspace_alloc(nwords,constant);
 481
 482     /* Copy it. */
 483     bcopy(old, new, nwords * sizeof(lispobj));
 484
 485     /* Deposit forwarding pointer. */
 486     result = make_lispobj(new, lowtag_of(thing));
 487     *old = result;
 488
 489     /* Scavenge it. */
 490     pscav(new, nwords, constant);
 491
 492     return result;
 493 }
 494
 495 /* We need to look at the layout to see whether it is a pure structure
 496  * class, and only then can we transport as constant. If it is pure,
 497  * we can ALWAYS transport as a constant. */
 498 static lispobj
 499 ptrans_instance(lispobj thing, lispobj header, boolean /* ignored */ constant)
 500 {
 501     lispobj layout = ((struct instance *)native_pointer(thing))->slots[0];
 502     lispobj pure = ((struct instance *)native_pointer(layout))->slots[15];
 503
 504     switch (pure) {
 505     case T:
 506         return (ptrans_boxed(thing, header, 1));
 507     case NIL:
 508         return (ptrans_boxed(thing, header, 0));
 509     case 0:
 510         {
 511             /* Substructure: special case for the COMPACT-INFO-ENVs,
 512              * where the instance may have a point to the dynamic
 513              * space placed into it (e.g. the cache-name slot), but
 514              * the lists and arrays at the time of a purify can be
 515              * moved to the RO space. */
 516             int nwords;
 517             lispobj result, *new, *old;
 518
 519             nwords = 1 + HeaderValue(header);
 520
 521             /* Allocate it */
 522             old = (lispobj *)native_pointer(thing);
 523             new = newspace_alloc(nwords, 0); /*  inconstant */
 524
 525             /* Copy it. */
 526             bcopy(old, new, nwords * sizeof(lispobj));
 527
 528             /* Deposit forwarding pointer. */
 529             result = make_lispobj(new, lowtag_of(thing));
 530             *old = result;
 531
 532             /* Scavenge it. */
 533             pscav(new, nwords, 1);
 534
 535             return result;
 536         }
 537     default:
 538         gc_abort();
 539         return NIL; /* dummy value: return something ... */
 540     }
 541 }
 542
 543 static lispobj
 544 ptrans_fdefn(lispobj thing, lispobj header)
 545 {
 546     int nwords;
 547     lispobj result, *new, *old, oldfn;
 548     struct fdefn *fdefn;
 549
 550     nwords = 1 + HeaderValue(header);
 551
 552     /* Allocate it */
 553     old = (lispobj *)native_pointer(thing);
 554     new = newspace_alloc(nwords, 0);    /* inconstant */
 555
 556     /* Copy it. */
 557     bcopy(old, new, nwords * sizeof(lispobj));
 558
 559     /* Deposit forwarding pointer. */
 560     result = make_lispobj(new, lowtag_of(thing));
 561     *old = result;
 562
 563     /* Scavenge the function. */
 564     fdefn = (struct fdefn *)new;
 565     oldfn = fdefn->fun;
 566     pscav(&fdefn->fun, 1, 0);
 567     if ((char *)oldfn + FUN_RAW_ADDR_OFFSET == fdefn->raw_addr)
 568         fdefn->raw_addr = (char *)fdefn->fun + FUN_RAW_ADDR_OFFSET;
 569
 570     return result;
 571 }
 572
 573 static lispobj
 574 ptrans_unboxed(lispobj thing, lispobj header)
 575 {
 576     int nwords;
 577     lispobj result, *new, *old;
 578
 579     nwords = 1 + HeaderValue(header);
 580
 581     /* Allocate it */
 582     old = (lispobj *)native_pointer(thing);
 583     new = newspace_alloc(nwords,1);     /* always constant */
 584
 585     /* copy it. */
 586     bcopy(old, new, nwords * sizeof(lispobj));
 587
 588     /* Deposit forwarding pointer. */
 589     result = make_lispobj(new , lowtag_of(thing));
 590     *old = result;
 591
 592     return result;
 593 }
 594
 595 static lispobj
 596 ptrans_vector(lispobj thing, int bits, int extra,
 597               boolean boxed, boolean constant)
 598 {
 599     struct vector *vector;
 600     int nwords;
 601     lispobj result, *new;
 602
 603     vector = (struct vector *)native_pointer(thing);
 604     nwords = 2 + (CEILING((fixnum_value(vector->length)+extra)*bits,32)>>5);
 605
 606     new=newspace_alloc(nwords, (constant || !boxed));
 607     bcopy(vector, new, nwords * sizeof(lispobj));
 608
 609     result = make_lispobj(new, lowtag_of(thing));
 610     vector->header = result;
 611
 612     if (boxed)
 613         pscav(new, nwords, constant);
 614
 615     return result;
 616 }
 617
 618 #ifdef LISP_FEATURE_X86
 619 static void
 620 apply_code_fixups_during_purify(struct code *old_code, struct code *new_code)
 621 {
 622     int nheader_words, ncode_words, nwords;
 623     void  *constants_start_addr, *constants_end_addr;
 624     void  *code_start_addr, *code_end_addr;
 625     lispobj fixups = NIL;
 626     unsigned  displacement = (unsigned)new_code - (unsigned)old_code;
 627     struct vector *fixups_vector;
 628
 629     ncode_words = fixnum_value(new_code->code_size);
 630     nheader_words = HeaderValue(*(lispobj *)new_code);
 631     nwords = ncode_words + nheader_words;
 632
 633     constants_start_addr = (void *)new_code + 5*4;
 634     constants_end_addr = (void *)new_code + nheader_words*4;
 635     code_start_addr = (void *)new_code + nheader_words*4;
 636     code_end_addr = (void *)new_code + nwords*4;
 637
 638     /* The first constant should be a pointer to the fixups for this
 639      * code objects. Check. */
 640     fixups = new_code->constants[0];
 641
 642     /* It will be 0 or the unbound-marker if there are no fixups, and
 643      * will be an other-pointer to a vector if it is valid. */
 644     if ((fixups==0) ||
 645         (fixups==UNBOUND_MARKER_WIDETAG) ||
 646         !is_lisp_pointer(fixups)) {
 647 #ifdef LISP_FEATURE_GENCGC
 648         /* Check for a possible errors. */
 649         sniff_code_object(new_code,displacement);
 650 #endif
 651         return;
 652     }
 653
 654     fixups_vector = (struct vector *)native_pointer(fixups);
 655
 656     /* Could be pointing to a forwarding pointer. */
 657     if (is_lisp_pointer(fixups) && (dynamic_pointer_p(fixups))
 658         && forwarding_pointer_p(*(lispobj *)fixups_vector)) {
 659         /* If so then follow it. */
 660         fixups_vector =
 661             (struct vector *)native_pointer(*(lispobj *)fixups_vector);
 662     }
 663
 664     if (widetag_of(fixups_vector->header) ==
 665         SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG) {
 666         /* We got the fixups for the code block. Now work through the
 667          * vector, and apply a fixup at each address. */
 668         int length = fixnum_value(fixups_vector->length);
 669         int i;
 670         for (i=0; i<length; i++) {
 671             unsigned offset = fixups_vector->data[i];
 672             /* Now check the current value of offset. */
 673             unsigned old_value =
 674                 *(unsigned *)((unsigned)code_start_addr + offset);
 675
 676             /* If it's within the old_code object then it must be an
 677              * absolute fixup (relative ones are not saved) */
 678             if ((old_value>=(unsigned)old_code)
 679                 && (old_value<((unsigned)old_code + nwords*4)))
 680                 /* So add the dispacement. */
 681                 *(unsigned *)((unsigned)code_start_addr + offset) = old_value
 682                     + displacement;
 683             else
 684                 /* It is outside the old code object so it must be a relative
 685                  * fixup (absolute fixups are not saved). So subtract the
 686                  * displacement. */
 687                 *(unsigned *)((unsigned)code_start_addr + offset) = old_value
 688                     - displacement;
 689         }
 690     }
 691
 692     /* No longer need the fixups. */
 693     new_code->constants[0] = 0;
 694
 695 #ifdef LISP_FEATURE_GENCGC
 696     /* Check for possible errors. */
 697     sniff_code_object(new_code,displacement);
 698 #endif
 699 }
 700 #endif
 701
 702 static lispobj
 703 ptrans_code(lispobj thing)
 704 {
 705     struct code *code, *new;
 706     int nwords;
 707     lispobj func, result;
 708
 709     code = (struct code *)native_pointer(thing);
 710     nwords = HeaderValue(code->header) + fixnum_value(code->code_size);
 711
 712     new = (struct code *)newspace_alloc(nwords,1); /* constant */
 713
 714     bcopy(code, new, nwords * sizeof(lispobj));
 715
 716 #ifdef LISP_FEATURE_X86
 717     apply_code_fixups_during_purify(code,new);
 718 #endif
 719
 720     result = make_lispobj(new, OTHER_POINTER_LOWTAG);
 721
 722     /* Stick in a forwarding pointer for the code object. */
 723     *(lispobj *)code = result;
 724
 725     /* Put in forwarding pointers for all the functions. */
 726     for (func = code->entry_points;
 727          func != NIL;
 728          func = ((struct simple_fun *)native_pointer(func))->next) {
 729
 730         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
 731
 732         *(lispobj *)native_pointer(func) = result + (func - thing);
 733     }
 734
 735     /* Arrange to scavenge the debug info later. */
 736     pscav_later(&new->debug_info, 1);
 737
 738     /* FIXME: why would this be a fixnum? */
 739     /* "why" is a hard word, but apparently for compiled functions the
 740        trace_table_offset contains the length of the instructions, as
 741        a fixnum.  See CODE-INST-AREA-LENGTH in
 742        src/compiler/target-disassem.lisp.  -- CSR, 2004-01-08 */
 743     if (!(fixnump(new->trace_table_offset)))
 744 #if 0
 745         pscav(&new->trace_table_offset, 1, 0);
 746 #else
 747         new->trace_table_offset = NIL; /* limit lifetime */
 748 #endif
 749
 750     /* Scavenge the constants. */
 751     pscav(new->constants, HeaderValue(new->header)-5, 1);
 752
 753     /* Scavenge all the functions. */
 754     pscav(&new->entry_points, 1, 1);
 755     for (func = new->entry_points;
 756          func != NIL;
 757          func = ((struct simple_fun *)native_pointer(func))->next) {
 758         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
 759         gc_assert(!dynamic_pointer_p(func));
 760
 761 #ifdef LISP_FEATURE_X86
 762         /* Temporarily convert the self pointer to a real function pointer. */
 763         ((struct simple_fun *)native_pointer(func))->self
 764             -= FUN_RAW_ADDR_OFFSET;
 765 #endif
 766         pscav(&((struct simple_fun *)native_pointer(func))->self, 2, 1);
 767 #ifdef LISP_FEATURE_X86
 768         ((struct simple_fun *)native_pointer(func))->self
 769             += FUN_RAW_ADDR_OFFSET;
 770 #endif
 771         pscav_later(&((struct simple_fun *)native_pointer(func))->name, 3);
 772     }
 773
 774     return result;
 775 }
 776
 777 static lispobj
 778 ptrans_func(lispobj thing, lispobj header)
 779 {
 780     int nwords;
 781     lispobj code, *new, *old, result;
 782     struct simple_fun *function;
 783
 784     /* Thing can either be a function header, a closure function
 785      * header, a closure, or a funcallable-instance. If it's a closure
 786      * or a funcallable-instance, we do the same as ptrans_boxed.
 787      * Otherwise we have to do something strange, 'cause it is buried
 788      * inside a code object. */
 789
 790     if (widetag_of(header) == SIMPLE_FUN_HEADER_WIDETAG) {
 791
 792         /* We can only end up here if the code object has not been
 793          * scavenged, because if it had been scavenged, forwarding pointers
 794          * would have been left behind for all the entry points. */
 795
 796         function = (struct simple_fun *)native_pointer(thing);
 797         code =
 798             make_lispobj
 799             ((native_pointer(thing) -
 800               (HeaderValue(function->header))), OTHER_POINTER_LOWTAG);
 801
 802         /* This will cause the function's header to be replaced with a
 803          * forwarding pointer. */
 804
 805         ptrans_code(code);
 806
 807         /* So we can just return that. */
 808         return function->header;
 809     }
 810     else {
 811         /* It's some kind of closure-like thing. */
 812         nwords = 1 + HeaderValue(header);
 813         old = (lispobj *)native_pointer(thing);
 814
 815         /* Allocate the new one.  FINs *must* not go in read_only
 816          * space.  Closures can; they never change */
 817
 818         new = newspace_alloc
 819             (nwords,(widetag_of(header)!=FUNCALLABLE_INSTANCE_HEADER_WIDETAG));
 820
 821         /* Copy it. */
 822         bcopy(old, new, nwords * sizeof(lispobj));
 823
 824         /* Deposit forwarding pointer. */
 825         result = make_lispobj(new, lowtag_of(thing));
 826         *old = result;
 827
 828         /* Scavenge it. */
 829         pscav(new, nwords, 0);
 830
 831         return result;
 832     }
 833 }
 834
 835 static lispobj
 836 ptrans_returnpc(lispobj thing, lispobj header)
 837 {
 838     lispobj code, new;
 839
 840     /* Find the corresponding code object. */
 841     code = thing - HeaderValue(header)*sizeof(lispobj);
 842
 843     /* Make sure it's been transported. */
 844     new = *(lispobj *)native_pointer(code);
 845     if (!forwarding_pointer_p(new))
 846         new = ptrans_code(code);
 847
 848     /* Maintain the offset: */
 849     return new + (thing - code);
 850 }
 851
 852 #define WORDS_PER_CONS CEILING(sizeof(struct cons) / sizeof(lispobj), 2)
 853
 854 static lispobj
 855 ptrans_list(lispobj thing, boolean constant)
 856 {
 857     struct cons *old, *new, *orig;
 858     int length;
 859
 860     orig = (struct cons *) newspace_alloc(0,constant);
 861     length = 0;
 862
 863     do {
 864         /* Allocate a new cons cell. */
 865         old = (struct cons *)native_pointer(thing);
 866         new = (struct cons *) newspace_alloc(WORDS_PER_CONS,constant);
 867
 868         /* Copy the cons cell and keep a pointer to the cdr. */
 869         new->car = old->car;
 870         thing = new->cdr = old->cdr;
 871
 872         /* Set up the forwarding pointer. */
 873         *(lispobj *)old = make_lispobj(new, LIST_POINTER_LOWTAG);
 874
 875         /* And count this cell. */
 876         length++;
 877     } while (lowtag_of(thing) == LIST_POINTER_LOWTAG &&
 878              dynamic_pointer_p(thing) &&
 879              !(forwarding_pointer_p(*(lispobj *)native_pointer(thing))));
 880
 881     /* Scavenge the list we just copied. */
 882     pscav((lispobj *)orig, length * WORDS_PER_CONS, constant);
 883
 884     return make_lispobj(orig, LIST_POINTER_LOWTAG);
 885 }
 886
 887 static lispobj
 888 ptrans_otherptr(lispobj thing, lispobj header, boolean constant)
 889 {
 890     switch (widetag_of(header)) {
 891         /* FIXME: this needs a reindent */
 892       case BIGNUM_WIDETAG:
 893       case SINGLE_FLOAT_WIDETAG:
 894       case DOUBLE_FLOAT_WIDETAG:
 895 #ifdef LONG_FLOAT_WIDETAG
 896       case LONG_FLOAT_WIDETAG:
 897 #endif
 898 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
 899       case COMPLEX_SINGLE_FLOAT_WIDETAG:
 900 #endif
 901 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
 902       case COMPLEX_DOUBLE_FLOAT_WIDETAG:
 903 #endif
 904 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
 905       case COMPLEX_LONG_FLOAT_WIDETAG:
 906 #endif
 907       case SAP_WIDETAG:
 908           return ptrans_unboxed(thing, header);
 909
 910       case RATIO_WIDETAG:
 911       case COMPLEX_WIDETAG:
 912       case SIMPLE_ARRAY_WIDETAG:
 913       case COMPLEX_BASE_STRING_WIDETAG:
 914       case COMPLEX_BIT_VECTOR_WIDETAG:
 915       case COMPLEX_VECTOR_NIL_WIDETAG:
 916       case COMPLEX_VECTOR_WIDETAG:
 917       case COMPLEX_ARRAY_WIDETAG:
 918         return ptrans_boxed(thing, header, constant);
 919
 920       case VALUE_CELL_HEADER_WIDETAG:
 921       case WEAK_POINTER_WIDETAG:
 922         return ptrans_boxed(thing, header, 0);
 923
 924       case SYMBOL_HEADER_WIDETAG:
 925         return ptrans_boxed(thing, header, 0);
 926
 927       case SIMPLE_ARRAY_NIL_WIDETAG:
 928         return ptrans_vector(thing, 0, 0, 0, constant);
 929
 930       case SIMPLE_BASE_STRING_WIDETAG:
 931         return ptrans_vector(thing, 8, 1, 0, constant);
 932
 933       case SIMPLE_BIT_VECTOR_WIDETAG:
 934         return ptrans_vector(thing, 1, 0, 0, constant);
 935
 936       case SIMPLE_VECTOR_WIDETAG:
 937         return ptrans_vector(thing, 32, 0, 1, constant);
 938
 939       case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
 940         return ptrans_vector(thing, 2, 0, 0, constant);
 941
 942       case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
 943         return ptrans_vector(thing, 4, 0, 0, constant);
 944
 945       case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
 946 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
 947       case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
 948       case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
 949 #endif
 950         return ptrans_vector(thing, 8, 0, 0, constant);
 951
 952       case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
 953 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
 954       case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
 955       case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
 956 #endif
 957         return ptrans_vector(thing, 16, 0, 0, constant);
 958
 959       case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
 960 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
 961       case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
 962       case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
 963 #endif
 964 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
 965       case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
 966       case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
 967 #endif
 968         return ptrans_vector(thing, 32, 0, 0, constant);
 969
 970       case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
 971         return ptrans_vector(thing, 32, 0, 0, constant);
 972
 973       case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
 974         return ptrans_vector(thing, 64, 0, 0, constant);
 975
 976 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
 977       case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
 978 #ifdef LISP_FEATURE_X86
 979         return ptrans_vector(thing, 96, 0, 0, constant);
 980 #endif
 981 #ifdef sparc
 982         return ptrans_vector(thing, 128, 0, 0, constant);
 983 #endif
 984 #endif
 985
 986 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
 987       case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
 988         return ptrans_vector(thing, 64, 0, 0, constant);
 989 #endif
 990
 991 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
 992       case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
 993         return ptrans_vector(thing, 128, 0, 0, constant);
 994 #endif
 995
 996 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
 997       case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
 998 #ifdef LISP_FEATURE_X86
 999         return ptrans_vector(thing, 192, 0, 0, constant);
1000 #endif
1001 #ifdef sparc
1002         return ptrans_vector(thing, 256, 0, 0, constant);
1003 #endif
1004 #endif
1005
1006       case CODE_HEADER_WIDETAG:
1007         return ptrans_code(thing);
1008
1009       case RETURN_PC_HEADER_WIDETAG:
1010         return ptrans_returnpc(thing, header);
1011
1012       case FDEFN_WIDETAG:
1013         return ptrans_fdefn(thing, header);
1014
1015       default:
1016         /* Should only come across other pointers to the above stuff. */
1017         gc_abort();
1018         return NIL;
1019     }
1020 }
1021
1022 static int
1023 pscav_fdefn(struct fdefn *fdefn)
1024 {
1025     boolean fix_func;
1026
1027     fix_func = ((char *)(fdefn->fun+FUN_RAW_ADDR_OFFSET) == fdefn->raw_addr);
1028     pscav(&fdefn->name, 1, 1);
1029     pscav(&fdefn->fun, 1, 0);
1030     if (fix_func)
1031         fdefn->raw_addr = (char *)(fdefn->fun + FUN_RAW_ADDR_OFFSET);
1032     return sizeof(struct fdefn) / sizeof(lispobj);
1033 }
1034
1035 #ifdef LISP_FEATURE_X86
1036 /* now putting code objects in static space */
1037 static int
1038 pscav_code(struct code*code)
1039 {
1040     int nwords;
1041     lispobj func;
1042     nwords = HeaderValue(code->header) + fixnum_value(code->code_size);
1043
1044     /* Arrange to scavenge the debug info later. */
1045     pscav_later(&code->debug_info, 1);
1046
1047     /* Scavenge the constants. */
1048     pscav(code->constants, HeaderValue(code->header)-5, 1);
1049
1050     /* Scavenge all the functions. */
1051     pscav(&code->entry_points, 1, 1);
1052     for (func = code->entry_points;
1053          func != NIL;
1054          func = ((struct simple_fun *)native_pointer(func))->next) {
1055         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
1056         gc_assert(!dynamic_pointer_p(func));
1057
1058 #ifdef LISP_FEATURE_X86
1059         /* Temporarily convert the self pointer to a real function
1060          * pointer. */
1061         ((struct simple_fun *)native_pointer(func))->self
1062             -= FUN_RAW_ADDR_OFFSET;
1063 #endif
1064         pscav(&((struct simple_fun *)native_pointer(func))->self, 2, 1);
1065 #ifdef LISP_FEATURE_X86
1066         ((struct simple_fun *)native_pointer(func))->self
1067             += FUN_RAW_ADDR_OFFSET;
1068 #endif
1069         pscav_later(&((struct simple_fun *)native_pointer(func))->name, 3);
1070     }
1071
1072     return CEILING(nwords,2);
1073 }
1074 #endif
1075
1076 static lispobj *
1077 pscav(lispobj *addr, int nwords, boolean constant)
1078 {
1079     lispobj thing, *thingp, header;
1080     int count = 0; /* (0 = dummy init value to stop GCC warning) */
1081     struct vector *vector;
1082
1083     while (nwords > 0) {
1084         thing = *addr;
1085         if (is_lisp_pointer(thing)) {
1086             /* It's a pointer. Is it something we might have to move? */
1087             if (dynamic_pointer_p(thing)) {
1088                 /* Maybe. Have we already moved it? */
1089                 thingp = (lispobj *)native_pointer(thing);
1090                 header = *thingp;
1091                 if (is_lisp_pointer(header) && forwarding_pointer_p(header))
1092                     /* Yep, so just copy the forwarding pointer. */
1093                     thing = header;
1094                 else {
1095                     /* Nope, copy the object. */
1096                     switch (lowtag_of(thing)) {
1097                       case FUN_POINTER_LOWTAG:
1098                         thing = ptrans_func(thing, header);
1099                         break;
1100
1101                       case LIST_POINTER_LOWTAG:
1102                         thing = ptrans_list(thing, constant);
1103                         break;
1104
1105                       case INSTANCE_POINTER_LOWTAG:
1106                         thing = ptrans_instance(thing, header, constant);
1107                         break;
1108
1109                       case OTHER_POINTER_LOWTAG:
1110                         thing = ptrans_otherptr(thing, header, constant);
1111                         break;
1112
1113                       default:
1114                         /* It was a pointer, but not one of them? */
1115                         gc_abort();
1116                     }
1117                 }
1118                 *addr = thing;
1119             }
1120             count = 1;
1121         }
1122         else if (thing & 3) {   /* FIXME: 3?  not 2? */
1123             /* It's an other immediate. Maybe the header for an unboxed */
1124             /* object. */
1125             switch (widetag_of(thing)) {
1126               case BIGNUM_WIDETAG:
1127               case SINGLE_FLOAT_WIDETAG:
1128               case DOUBLE_FLOAT_WIDETAG:
1129 #ifdef LONG_FLOAT_WIDETAG
1130               case LONG_FLOAT_WIDETAG:
1131 #endif
1132               case SAP_WIDETAG:
1133                 /* It's an unboxed simple object. */
1134                 count = HeaderValue(thing)+1;
1135                 break;
1136
1137               case SIMPLE_VECTOR_WIDETAG:
1138                   if (HeaderValue(thing) == subtype_VectorValidHashing) {
1139                     *addr = (subtype_VectorMustRehash << N_WIDETAG_BITS) |
1140                         SIMPLE_VECTOR_WIDETAG;
1141                   }
1142                 count = 1;
1143                 break;
1144
1145               case SIMPLE_ARRAY_NIL_WIDETAG:
1146                 count = 2;
1147                 break;
1148
1149               case SIMPLE_BASE_STRING_WIDETAG:
1150                 vector = (struct vector *)addr;
1151                 count = CEILING(NWORDS(fixnum_value(vector->length)+1,4)+2,2);
1152                 break;
1153
1154               case SIMPLE_BIT_VECTOR_WIDETAG:
1155                 vector = (struct vector *)addr;
1156                 count = CEILING(NWORDS(fixnum_value(vector->length),32)+2,2);
1157                 break;
1158
1159               case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
1160                 vector = (struct vector *)addr;
1161                 count = CEILING(NWORDS(fixnum_value(vector->length),16)+2,2);
1162                 break;
1163
1164               case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
1165                 vector = (struct vector *)addr;
1166                 count = CEILING(NWORDS(fixnum_value(vector->length),8)+2,2);
1167                 break;
1168
1169               case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
1170 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
1171               case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
1172               case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
1173 #endif
1174                 vector = (struct vector *)addr;
1175                 count = CEILING(NWORDS(fixnum_value(vector->length),4)+2,2);
1176                 break;
1177
1178               case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
1179 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
1180               case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
1181               case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
1182 #endif
1183                 vector = (struct vector *)addr;
1184                 count = CEILING(NWORDS(fixnum_value(vector->length),2)+2,2);
1185                 break;
1186
1187               case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
1188 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
1189               case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
1190               case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
1191 #endif
1192 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
1193               case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
1194               case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
1195 #endif
1196                 vector = (struct vector *)addr;
1197                 count = CEILING(fixnum_value(vector->length)+2,2);
1198                 break;
1199
1200               case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
1201                 vector = (struct vector *)addr;
1202                 count = CEILING(fixnum_value(vector->length)+2,2);
1203                 break;
1204
1205               case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
1206 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
1207               case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
1208 #endif
1209                 vector = (struct vector *)addr;
1210                 count = fixnum_value(vector->length)*2+2;
1211                 break;
1212
1213 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
1214               case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
1215                 vector = (struct vector *)addr;
1216 #ifdef LISP_FEATURE_X86
1217                 count = fixnum_value(vector->length)*3+2;
1218 #endif
1219 #ifdef sparc
1220                 count = fixnum_value(vector->length)*4+2;
1221 #endif
1222                 break;
1223 #endif
1224
1225 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
1226               case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
1227                 vector = (struct vector *)addr;
1228                 count = fixnum_value(vector->length)*4+2;
1229                 break;
1230 #endif
1231
1232 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
1233               case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
1234                 vector = (struct vector *)addr;
1235 #ifdef LISP_FEATURE_X86
1236                 count = fixnum_value(vector->length)*6+2;
1237 #endif
1238 #ifdef sparc
1239                 count = fixnum_value(vector->length)*8+2;
1240 #endif
1241                 break;
1242 #endif
1243
1244               case CODE_HEADER_WIDETAG:
1245 #ifndef LISP_FEATURE_X86
1246                 gc_abort(); /* no code headers in static space */
1247 #else
1248                 count = pscav_code((struct code*)addr);
1249 #endif
1250                 break;
1251
1252               case SIMPLE_FUN_HEADER_WIDETAG:
1253               case RETURN_PC_HEADER_WIDETAG:
1254                 /* We should never hit any of these, 'cause they occur
1255                  * buried in the middle of code objects. */
1256                 gc_abort();
1257                 break;
1258
1259 #ifdef LISP_FEATURE_X86
1260               case CLOSURE_HEADER_WIDETAG:
1261               case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
1262                 /* The function self pointer needs special care on the
1263                  * x86 because it is the real entry point. */
1264                 {
1265                   lispobj fun = ((struct closure *)addr)->fun
1266                     - FUN_RAW_ADDR_OFFSET;
1267                   pscav(&fun, 1, constant);
1268                   ((struct closure *)addr)->fun = fun + FUN_RAW_ADDR_OFFSET;
1269                 }
1270                 count = 2;
1271                 break;
1272 #endif
1273
1274               case WEAK_POINTER_WIDETAG:
1275                 /* Weak pointers get preserved during purify, 'cause I
1276                  * don't feel like figuring out how to break them. */
1277                 pscav(addr+1, 2, constant);
1278                 count = 4;
1279                 break;
1280
1281               case FDEFN_WIDETAG:
1282                 /* We have to handle fdefn objects specially, so we
1283                  * can fix up the raw function address. */
1284                 count = pscav_fdefn((struct fdefn *)addr);
1285                 break;
1286
1287               default:
1288                 count = 1;
1289                 break;
1290             }
1291         }
1292         else {
1293             /* It's a fixnum. */
1294             count = 1;
1295         }
1296
1297         addr += count;
1298         nwords -= count;
1299     }
1300
1301     return addr;
1302 }
1303
1304 int
1305 purify(lispobj static_roots, lispobj read_only_roots)
1306 {
1307     lispobj *clean;
1308     int count, i;
1309     struct later *laters, *next;
1310     struct thread *thread;
1311
1312     if(all_threads->next) {
1313         /* FIXME: there should be _some_ sensible error reporting
1314          * convention.  See following comment too */
1315         fprintf(stderr,"Can't purify when more than one thread exists\n");
1316         fflush(stderr);
1317         return 0;
1318     }
1319
1320 #ifdef PRINTNOISE
1321     printf("[doing purification:");
1322     fflush(stdout);
1323 #endif
1324 #ifdef LISP_FEATURE_GENCGC
1325     gc_alloc_update_all_page_tables();
1326 #endif
1327     for_each_thread(thread)
1328         if (fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread)) != 0) {
1329         /* FIXME: 1. What does this mean? 2. It shouldn't be reporting
1330          * its error simply by a. printing a string b. to stdout instead
1331          * of stderr. */
1332         printf(" Ack! Can't purify interrupt contexts. ");
1333         fflush(stdout);
1334         return 0;
1335     }
1336
1337 #if defined(LISP_FEATURE_X86)
1338     dynamic_space_free_pointer =
1339       (lispobj*)SymbolValue(ALLOCATION_POINTER,0);
1340 #endif
1341
1342     read_only_end = read_only_free =
1343         (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
1344     static_end = static_free =
1345         (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
1346
1347 #ifdef PRINTNOISE
1348     printf(" roots");
1349     fflush(stdout);
1350 #endif
1351
1352 #if (defined(LISP_FEATURE_GENCGC) && defined(LISP_FEATURE_X86))
1353     /* note this expects only one thread to be active.  We'd have to
1354      * stop all the others in the same way as GC does if we wanted
1355      * PURIFY to work when >1 thread exists */
1356     setup_i386_stack_scav(((&static_roots)-2),
1357                           ((void *)all_threads->control_stack_end));
1358 #endif
1359
1360     pscav(&static_roots, 1, 0);
1361     pscav(&read_only_roots, 1, 1);
1362
1363 #ifdef PRINTNOISE
1364     printf(" handlers");
1365     fflush(stdout);
1366 #endif
1367     pscav((lispobj *) all_threads->interrupt_data->interrupt_handlers,
1368           sizeof(all_threads->interrupt_data->interrupt_handlers)
1369           / sizeof(lispobj),
1370           0);
1371
1372 #ifdef PRINTNOISE
1373     printf(" stack");
1374     fflush(stdout);
1375 #endif
1376 #ifndef LISP_FEATURE_X86
1377     pscav((lispobj *)all_threads->control_stack_start,
1378           current_control_stack_pointer -
1379           all_threads->control_stack_start,
1380           0);
1381 #else
1382 #ifdef LISP_FEATURE_GENCGC
1383     pscav_i386_stack();
1384 #endif
1385 #endif
1386
1387 #ifdef PRINTNOISE
1388     printf(" bindings");
1389     fflush(stdout);
1390 #endif
1391 #if !defined(LISP_FEATURE_X86)
1392     pscav( (lispobj *)all_threads->binding_stack_start,
1393           (lispobj *)current_binding_stack_pointer -
1394            all_threads->binding_stack_start,
1395           0);
1396 #else
1397     for_each_thread(thread) {
1398         pscav( (lispobj *)thread->binding_stack_start,
1399                (lispobj *)SymbolValue(BINDING_STACK_POINTER,thread) -
1400                (lispobj *)thread->binding_stack_start,
1401           0);
1402         pscav( (lispobj *) (thread+1),
1403                fixnum_value(SymbolValue(FREE_TLS_INDEX,0)) -
1404                (sizeof (struct thread))/(sizeof (lispobj)),
1405           0);
1406     }
1407
1408
1409 #endif
1410
1411     /* The original CMU CL code had scavenge-read-only-space code
1412      * controlled by the Lisp-level variable
1413      * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
1414      * wasn't documented under what circumstances it was useful or
1415      * safe to turn it on, so it's been turned off in SBCL. If you
1416      * want/need this functionality, and can test and document it,
1417      * please submit a patch. */
1418 #if 0
1419     if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != UNBOUND_MARKER_WIDETAG
1420         && SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
1421       unsigned  read_only_space_size =
1422           (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
1423           (lispobj *)READ_ONLY_SPACE_START;
1424       fprintf(stderr,
1425               "scavenging read only space: %d bytes\n",
1426               read_only_space_size * sizeof(lispobj));
1427       pscav( (lispobj *)READ_ONLY_SPACE_START, read_only_space_size, 0);
1428     }
1429 #endif
1430
1431 #ifdef PRINTNOISE
1432     printf(" static");
1433     fflush(stdout);
1434 #endif
1435     clean = (lispobj *)STATIC_SPACE_START;
1436     do {
1437         while (clean != static_free)
1438             clean = pscav(clean, static_free - clean, 0);
1439         laters = later_blocks;
1440         count = later_count;
1441         later_blocks = NULL;
1442         later_count = 0;
1443         while (laters != NULL) {
1444             for (i = 0; i < count; i++) {
1445                 if (laters->u[i].count == 0) {
1446                     ;
1447                 } else if (laters->u[i].count <= LATERMAXCOUNT) {
1448                     pscav(laters->u[i+1].ptr, laters->u[i].count, 1);
1449                     i++;
1450                 } else {
1451                     pscav(laters->u[i].ptr, 1, 1);
1452                 }
1453             }
1454             next = laters->next;
1455             free(laters);
1456             laters = next;
1457             count = LATERBLOCKSIZE;
1458         }
1459     } while (clean != static_free || later_blocks != NULL);
1460
1461 #ifdef PRINTNOISE
1462     printf(" cleanup");
1463     fflush(stdout);
1464 #endif
1465
1466     os_zero((os_vm_address_t) current_dynamic_space,
1467             (os_vm_size_t) DYNAMIC_SPACE_SIZE);
1468
1469     /* Zero the stack. Note that the stack is also zeroed by SUB-GC
1470      * calling SCRUB-CONTROL-STACK - this zeros the stack on the x86. */
1471 #ifndef LISP_FEATURE_X86
1472     os_zero((os_vm_address_t) current_control_stack_pointer,
1473             (os_vm_size_t)
1474             ((all_threads->control_stack_end -
1475               current_control_stack_pointer) * sizeof(lispobj)));
1476 #endif
1477
1478     /* It helps to update the heap free pointers so that free_heap can
1479      * verify after it's done. */
1480     SetSymbolValue(READ_ONLY_SPACE_FREE_POINTER, (lispobj)read_only_free,0);
1481     SetSymbolValue(STATIC_SPACE_FREE_POINTER, (lispobj)static_free,0);
1482
1483 #if !defined(LISP_FEATURE_X86)
1484     dynamic_space_free_pointer = current_dynamic_space;
1485     set_auto_gc_trigger(bytes_consed_between_gcs);
1486 #else
1487 #if defined LISP_FEATURE_GENCGC
1488     gc_free_heap();
1489 #else
1490 #error unsupported case /* in CMU CL, was "ibmrt using GC" */
1491 #endif
1492 #endif
1493
1494 #ifdef PRINTNOISE
1495     printf(" done]\n");
1496     fflush(stdout);
1497 #endif
1498     return 0;
1499 }