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 #if (defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_LINUX))
  21 #include <sys/ptrace.h>
  22 #include <linux/user.h>
  23 #endif
  24 #include <errno.h>
  25
  26 #include "runtime.h"
  27 #include "os.h"
  28 #include "sbcl.h"
  29 #include "globals.h"
  30 #include "validate.h"
  31 #include "interrupt.h"
  32 #include "purify.h"
  33 #include "interr.h"
  34 #include "gc.h"
  35 #include "gc-internal.h"
  36 #include "thread.h"
  37 #include "genesis/primitive-objects.h"
  38 #include "genesis/static-symbols.h"
  39
  40 #define PRINTNOISE
  41
  42 #if defined(__i386__)
  43 /* again, what's so special about the x86 that this is differently
  44  * visible there than on other platforms? -dan 20010125
  45  */
  46 static lispobj *dynamic_space_free_pointer;
  47 #endif
  48 extern unsigned long bytes_consed_between_gcs;
  49
  50 #define gc_abort() \
  51   lose("GC invariant lost, file \"%s\", line %d", __FILE__, __LINE__)
  52
  53 #if 1
  54 #define gc_assert(ex) do { \
  55         if (!(ex)) gc_abort(); \
  56 } while (0)
  57 #else
  58 #define gc_assert(ex)
  59 #endif
  60
  61 \f
  62 /* These hold the original end of the read_only and static spaces so
  63  * we can tell what are forwarding pointers. */
  64
  65 static lispobj *read_only_end, *static_end;
  66
  67 static lispobj *read_only_free, *static_free;
  68
  69 static lispobj *pscav(lispobj *addr, int nwords, boolean constant);
  70
  71 #define LATERBLOCKSIZE 1020
  72 #define LATERMAXCOUNT 10
  73
  74 static struct
  75 later {
  76     struct later *next;
  77     union {
  78         lispobj *ptr;
  79         int count;
  80     } u[LATERBLOCKSIZE];
  81 } *later_blocks = NULL;
  82 static int later_count = 0;
  83
  84 #define CEILING(x,y) (((x) + ((y) - 1)) & (~((y) - 1)))
  85 #define NWORDS(x,y) (CEILING((x),(y)) / (y))
  86
  87 /* FIXME: Shouldn't this be defined in sbcl.h?  See also notes in
  88  * cheneygc.c */
  89
  90 #ifdef sparc
  91 #define FUN_RAW_ADDR_OFFSET 0
  92 #else
  93 #define FUN_RAW_ADDR_OFFSET (6*sizeof(lispobj) - FUN_POINTER_LOWTAG)
  94 #endif
  95 \f
  96 static boolean
  97 forwarding_pointer_p(lispobj obj)
  98 {
  99     lispobj *ptr = native_pointer(obj);
 100
 101     return ((static_end <= ptr && ptr <= static_free) ||
 102             (read_only_end <= ptr && ptr <= read_only_free));
 103 }
 104
 105 static boolean
 106 dynamic_pointer_p(lispobj ptr)
 107 {
 108 #ifndef __i386__
 109     return (ptr >= (lispobj)current_dynamic_space
 110             &&
 111             ptr < (lispobj)dynamic_space_free_pointer);
 112 #else
 113     /* Be more conservative, and remember, this is a maybe. */
 114     return (ptr >= (lispobj)DYNAMIC_SPACE_START
 115             &&
 116             ptr < (lispobj)dynamic_space_free_pointer);
 117 #endif
 118 }
 119
 120 \f
 121 #ifdef __i386__
 122
 123 #ifdef LISP_FEATURE_GENCGC
 124 /*
 125  * enhanced x86/GENCGC stack scavenging by Douglas Crosher
 126  *
 127  * Scavenging the stack on the i386 is problematic due to conservative
 128  * roots and raw return addresses. Here it is handled in two passes:
 129  * the first pass runs before any objects are moved and tries to
 130  * identify valid pointers and return address on the stack, the second
 131  * pass scavenges these.
 132  */
 133
 134 static unsigned pointer_filter_verbose = 0;
 135
 136 /* FIXME: This is substantially the same code as
 137  * possibly_valid_dynamic_space_pointer in gencgc.c.  The only
 138  * relevant difference seems to be that the gencgc code also checks
 139  * for raw pointers into Code objects */
 140
 141 static int
 142 valid_dynamic_space_pointer(lispobj *pointer, lispobj *start_addr)
 143 {
 144     /* If it's not a return address then it needs to be a valid Lisp
 145      * pointer. */
 146     if (!is_lisp_pointer((lispobj)pointer))
 147         return 0;
 148
 149     /* Check that the object pointed to is consistent with the pointer
 150      * low tag. */
 151     switch (lowtag_of((lispobj)pointer)) {
 152     case FUN_POINTER_LOWTAG:
 153         /* Start_addr should be the enclosing code object, or a closure
 154          * header. */
 155         switch (widetag_of(*start_addr)) {
 156         case CODE_HEADER_WIDETAG:
 157             /* This case is probably caught above. */
 158             break;
 159         case CLOSURE_HEADER_WIDETAG:
 160         case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
 161             if ((int)pointer != ((int)start_addr+FUN_POINTER_LOWTAG)) {
 162                 if (pointer_filter_verbose) {
 163                     fprintf(stderr,"*Wf2: %x %x %x\n", (unsigned int) pointer,
 164                             (unsigned int) start_addr, *start_addr);
 165                 }
 166                 return 0;
 167             }
 168             break;
 169         default:
 170             if (pointer_filter_verbose) {
 171                 fprintf(stderr,"*Wf3: %x %x %x\n", (unsigned int) pointer,
 172                         (unsigned int) start_addr, *start_addr);
 173             }
 174             return 0;
 175         }
 176         break;
 177     case LIST_POINTER_LOWTAG:
 178         if ((int)pointer != ((int)start_addr+LIST_POINTER_LOWTAG)) {
 179             if (pointer_filter_verbose)
 180                 fprintf(stderr,"*Wl1: %x %x %x\n", (unsigned int) pointer,
 181                         (unsigned int) start_addr, *start_addr);
 182             return 0;
 183         }
 184         /* Is it plausible cons? */
 185         if ((is_lisp_pointer(start_addr[0])
 186             || ((start_addr[0] & 3) == 0) /* fixnum */
 187             || (widetag_of(start_addr[0]) == BASE_CHAR_WIDETAG)
 188             || (widetag_of(start_addr[0]) == UNBOUND_MARKER_WIDETAG))
 189            && (is_lisp_pointer(start_addr[1])
 190                || ((start_addr[1] & 3) == 0) /* fixnum */
 191                || (widetag_of(start_addr[1]) == BASE_CHAR_WIDETAG)
 192                || (widetag_of(start_addr[1]) == UNBOUND_MARKER_WIDETAG))) {
 193             break;
 194         } else {
 195             if (pointer_filter_verbose) {
 196                 fprintf(stderr,"*Wl2: %x %x %x\n", (unsigned int) pointer,
 197                         (unsigned int) start_addr, *start_addr);
 198             }
 199             return 0;
 200         }
 201     case INSTANCE_POINTER_LOWTAG:
 202         if ((int)pointer != ((int)start_addr+INSTANCE_POINTER_LOWTAG)) {
 203             if (pointer_filter_verbose) {
 204                 fprintf(stderr,"*Wi1: %x %x %x\n", (unsigned int) pointer,
 205                         (unsigned int) start_addr, *start_addr);
 206             }
 207             return 0;
 208         }
 209         if (widetag_of(start_addr[0]) != INSTANCE_HEADER_WIDETAG) {
 210             if (pointer_filter_verbose) {
 211                 fprintf(stderr,"*Wi2: %x %x %x\n", (unsigned int) pointer,
 212                         (unsigned int) start_addr, *start_addr);
 213             }
 214             return 0;
 215         }
 216         break;
 217     case OTHER_POINTER_LOWTAG:
 218         if ((int)pointer != ((int)start_addr+OTHER_POINTER_LOWTAG)) {
 219             if (pointer_filter_verbose) {
 220                 fprintf(stderr,"*Wo1: %x %x %x\n", (unsigned int) pointer,
 221                         (unsigned int) start_addr, *start_addr);
 222             }
 223             return 0;
 224         }
 225         /* Is it plausible? Not a cons. XXX should check the headers. */
 226         if (is_lisp_pointer(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
 227             if (pointer_filter_verbose) {
 228                 fprintf(stderr,"*Wo2: %x %x %x\n", (unsigned int) pointer,
 229                         (unsigned int) start_addr, *start_addr);
 230             }
 231             return 0;
 232         }
 233         switch (widetag_of(start_addr[0])) {
 234         case UNBOUND_MARKER_WIDETAG:
 235         case BASE_CHAR_WIDETAG:
 236             if (pointer_filter_verbose) {
 237                 fprintf(stderr,"*Wo3: %x %x %x\n", (unsigned int) pointer,
 238                         (unsigned int) start_addr, *start_addr);
 239             }
 240             return 0;
 241
 242             /* only pointed to by function pointers? */
 243         case CLOSURE_HEADER_WIDETAG:
 244         case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
 245             if (pointer_filter_verbose) {
 246                 fprintf(stderr,"*Wo4: %x %x %x\n", (unsigned int) pointer,
 247                         (unsigned int) start_addr, *start_addr);
 248             }
 249             return 0;
 250
 251         case INSTANCE_HEADER_WIDETAG:
 252             if (pointer_filter_verbose) {
 253                 fprintf(stderr,"*Wo5: %x %x %x\n", (unsigned int) pointer,
 254                         (unsigned int) start_addr, *start_addr);
 255             }
 256             return 0;
 257
 258             /* the valid other immediate pointer objects */
 259         case SIMPLE_VECTOR_WIDETAG:
 260         case RATIO_WIDETAG:
 261         case COMPLEX_WIDETAG:
 262 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
 263         case COMPLEX_SINGLE_FLOAT_WIDETAG:
 264 #endif
 265 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
 266         case COMPLEX_DOUBLE_FLOAT_WIDETAG:
 267 #endif
 268 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
 269         case COMPLEX_LONG_FLOAT_WIDETAG:
 270 #endif
 271         case SIMPLE_ARRAY_WIDETAG:
 272         case COMPLEX_BASE_STRING_WIDETAG:
 273         case COMPLEX_VECTOR_NIL_WIDETAG:
 274         case COMPLEX_BIT_VECTOR_WIDETAG:
 275         case COMPLEX_VECTOR_WIDETAG:
 276         case COMPLEX_ARRAY_WIDETAG:
 277         case VALUE_CELL_HEADER_WIDETAG:
 278         case SYMBOL_HEADER_WIDETAG:
 279         case FDEFN_WIDETAG:
 280         case CODE_HEADER_WIDETAG:
 281         case BIGNUM_WIDETAG:
 282         case SINGLE_FLOAT_WIDETAG:
 283         case DOUBLE_FLOAT_WIDETAG:
 284 #ifdef LONG_FLOAT_WIDETAG
 285         case LONG_FLOAT_WIDETAG:
 286 #endif
 287         case SIMPLE_ARRAY_NIL_WIDETAG:
 288         case SIMPLE_BASE_STRING_WIDETAG:
 289         case SIMPLE_BIT_VECTOR_WIDETAG:
 290         case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
 291         case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
 292         case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
 293         case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
 294         case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
 295 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
 296         case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
 297 #endif
 298 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
 299         case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
 300 #endif
 301 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
 302         case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
 303 #endif
 304 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
 305         case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
 306 #endif
 307         case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
 308         case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
 309 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
 310         case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
 311 #endif
 312 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
 313         case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
 314 #endif
 315 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
 316         case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
 317 #endif
 318 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
 319         case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
 320 #endif
 321         case SAP_WIDETAG:
 322         case WEAK_POINTER_WIDETAG:
 323             break;
 324
 325         default:
 326             if (pointer_filter_verbose) {
 327                 fprintf(stderr,"*Wo6: %x %x %x\n", (unsigned int) pointer,
 328                         (unsigned int) start_addr, *start_addr);
 329             }
 330             return 0;
 331         }
 332         break;
 333     default:
 334         if (pointer_filter_verbose) {
 335             fprintf(stderr,"*W?: %x %x %x\n", (unsigned int) pointer,
 336                     (unsigned int) start_addr, *start_addr);
 337         }
 338         return 0;
 339     }
 340
 341     /* looks good */
 342     return 1;
 343 }
 344
 345 #define MAX_STACK_POINTERS 256
 346 lispobj *valid_stack_locations[MAX_STACK_POINTERS];
 347 unsigned int num_valid_stack_locations;
 348
 349 #define MAX_STACK_RETURN_ADDRESSES 128
 350 lispobj *valid_stack_ra_locations[MAX_STACK_RETURN_ADDRESSES];
 351 lispobj *valid_stack_ra_code_objects[MAX_STACK_RETURN_ADDRESSES];
 352 unsigned int num_valid_stack_ra_locations;
 353
 354 /* Identify valid stack slots. */
 355 static void
 356 setup_i386_stack_scav(lispobj *lowaddr, lispobj *base)
 357 {
 358     lispobj *sp = lowaddr;
 359     num_valid_stack_locations = 0;
 360     num_valid_stack_ra_locations = 0;
 361     for (sp = lowaddr; sp < base; sp++) {
 362         lispobj thing = *sp;
 363         /* Find the object start address */
 364         lispobj *start_addr = search_dynamic_space((void *)thing);
 365         if (start_addr) {
 366             /* We need to allow raw pointers into Code objects for
 367              * return addresses. This will also pick up pointers to
 368              * functions in code objects. */
 369             if (widetag_of(*start_addr) == CODE_HEADER_WIDETAG) {
 370                 /* FIXME asserting here is a really dumb thing to do.
 371                  * If we've overflowed some arbitrary static limit, we
 372                  * should just refuse to purify, instead of killing
 373                  * the whole lisp session
 374                  */
 375                 gc_assert(num_valid_stack_ra_locations <
 376                           MAX_STACK_RETURN_ADDRESSES);
 377                 valid_stack_ra_locations[num_valid_stack_ra_locations] = sp;
 378                 valid_stack_ra_code_objects[num_valid_stack_ra_locations++] =
 379                     (lispobj *)((int)start_addr + OTHER_POINTER_LOWTAG);
 380             } else {
 381                 if (valid_dynamic_space_pointer((void *)thing, start_addr)) {
 382                     gc_assert(num_valid_stack_locations < MAX_STACK_POINTERS);
 383                     valid_stack_locations[num_valid_stack_locations++] = sp;
 384                 }
 385             }
 386         }
 387     }
 388     if (pointer_filter_verbose) {
 389         fprintf(stderr, "number of valid stack pointers = %d\n",
 390                 num_valid_stack_locations);
 391         fprintf(stderr, "number of stack return addresses = %d\n",
 392                 num_valid_stack_ra_locations);
 393     }
 394 }
 395
 396 static void
 397 pscav_i386_stack(void)
 398 {
 399     int i;
 400
 401     for (i = 0; i < num_valid_stack_locations; i++)
 402         pscav(valid_stack_locations[i], 1, 0);
 403
 404     for (i = 0; i < num_valid_stack_ra_locations; i++) {
 405         lispobj code_obj = (lispobj)valid_stack_ra_code_objects[i];
 406         pscav(&code_obj, 1, 0);
 407         if (pointer_filter_verbose) {
 408             fprintf(stderr,"*C moved RA %x to %x; for code object %x to %x\n",
 409                     *valid_stack_ra_locations[i],
 410                     (int)(*valid_stack_ra_locations[i])
 411                     - ((int)valid_stack_ra_code_objects[i] - (int)code_obj),
 412                     (unsigned int) valid_stack_ra_code_objects[i], code_obj);
 413         }
 414         *valid_stack_ra_locations[i] =
 415             ((int)(*valid_stack_ra_locations[i])
 416              - ((int)valid_stack_ra_code_objects[i] - (int)code_obj));
 417     }
 418 }
 419 #endif
 420 #endif
 421
 422 \f
 423 static void
 424 pscav_later(lispobj *where, int count)
 425 {
 426     struct later *new;
 427
 428     if (count > LATERMAXCOUNT) {
 429         while (count > LATERMAXCOUNT) {
 430             pscav_later(where, LATERMAXCOUNT);
 431             count -= LATERMAXCOUNT;
 432             where += LATERMAXCOUNT;
 433         }
 434     }
 435     else {
 436         if (later_blocks == NULL || later_count == LATERBLOCKSIZE ||
 437             (later_count == LATERBLOCKSIZE-1 && count > 1)) {
 438             new  = (struct later *)malloc(sizeof(struct later));
 439             new->next = later_blocks;
 440             if (later_blocks && later_count < LATERBLOCKSIZE)
 441                 later_blocks->u[later_count].ptr = NULL;
 442             later_blocks = new;
 443             later_count = 0;
 444         }
 445
 446         if (count != 1)
 447             later_blocks->u[later_count++].count = count;
 448         later_blocks->u[later_count++].ptr = where;
 449     }
 450 }
 451
 452 static lispobj
 453 ptrans_boxed(lispobj thing, lispobj header, boolean constant)
 454 {
 455     int nwords;
 456     lispobj result, *new, *old;
 457
 458     nwords = 1 + HeaderValue(header);
 459
 460     /* Allocate it */
 461     old = (lispobj *)native_pointer(thing);
 462     if (constant) {
 463         new = read_only_free;
 464         read_only_free += CEILING(nwords, 2);
 465     }
 466     else {
 467         new = static_free;
 468         static_free += CEILING(nwords, 2);
 469     }
 470
 471     /* Copy it. */
 472     bcopy(old, new, nwords * sizeof(lispobj));
 473
 474     /* Deposit forwarding pointer. */
 475     result = make_lispobj(new, lowtag_of(thing));
 476     *old = result;
 477
 478     /* Scavenge it. */
 479     pscav(new, nwords, constant);
 480
 481     return result;
 482 }
 483
 484 /* We need to look at the layout to see whether it is a pure structure
 485  * class, and only then can we transport as constant. If it is pure,
 486  * we can ALWAYS transport as a constant. */
 487 static lispobj
 488 ptrans_instance(lispobj thing, lispobj header, boolean constant)
 489 {
 490     lispobj layout = ((struct instance *)native_pointer(thing))->slots[0];
 491     lispobj pure = ((struct instance *)native_pointer(layout))->slots[15];
 492
 493     switch (pure) {
 494     case T:
 495         return (ptrans_boxed(thing, header, 1));
 496     case NIL:
 497         return (ptrans_boxed(thing, header, 0));
 498     case 0:
 499         {
 500             /* Substructure: special case for the COMPACT-INFO-ENVs,
 501              * where the instance may have a point to the dynamic
 502              * space placed into it (e.g. the cache-name slot), but
 503              * the lists and arrays at the time of a purify can be
 504              * moved to the RO space. */
 505             int nwords;
 506             lispobj result, *new, *old;
 507
 508             nwords = 1 + HeaderValue(header);
 509
 510             /* Allocate it */
 511             old = (lispobj *)native_pointer(thing);
 512             new = static_free;
 513             static_free += CEILING(nwords, 2);
 514
 515             /* Copy it. */
 516             bcopy(old, new, nwords * sizeof(lispobj));
 517
 518             /* Deposit forwarding pointer. */
 519             result = make_lispobj(new, lowtag_of(thing));
 520             *old = result;
 521
 522             /* Scavenge it. */
 523             pscav(new, nwords, 1);
 524
 525             return result;
 526         }
 527     default:
 528         gc_abort();
 529         return NIL; /* dummy value: return something ... */
 530     }
 531 }
 532
 533 static lispobj
 534 ptrans_fdefn(lispobj thing, lispobj header)
 535 {
 536     int nwords;
 537     lispobj result, *new, *old, oldfn;
 538     struct fdefn *fdefn;
 539
 540     nwords = 1 + HeaderValue(header);
 541
 542     /* Allocate it */
 543     old = (lispobj *)native_pointer(thing);
 544     new = static_free;
 545     static_free += CEILING(nwords, 2);
 546
 547     /* Copy it. */
 548     bcopy(old, new, nwords * sizeof(lispobj));
 549
 550     /* Deposit forwarding pointer. */
 551     result = make_lispobj(new, lowtag_of(thing));
 552     *old = result;
 553
 554     /* Scavenge the function. */
 555     fdefn = (struct fdefn *)new;
 556     oldfn = fdefn->fun;
 557     pscav(&fdefn->fun, 1, 0);
 558     if ((char *)oldfn + FUN_RAW_ADDR_OFFSET == fdefn->raw_addr)
 559         fdefn->raw_addr = (char *)fdefn->fun + FUN_RAW_ADDR_OFFSET;
 560
 561     return result;
 562 }
 563
 564 static lispobj
 565 ptrans_unboxed(lispobj thing, lispobj header)
 566 {
 567     int nwords;
 568     lispobj result, *new, *old;
 569
 570     nwords = 1 + HeaderValue(header);
 571
 572     /* Allocate it */
 573     old = (lispobj *)native_pointer(thing);
 574     new = read_only_free;
 575     read_only_free += CEILING(nwords, 2);
 576
 577     /* Copy it. */
 578     bcopy(old, new, nwords * sizeof(lispobj));
 579
 580     /* Deposit forwarding pointer. */
 581     result = make_lispobj(new , lowtag_of(thing));
 582     *old = result;
 583
 584     return result;
 585 }
 586
 587 static lispobj
 588 ptrans_vector(lispobj thing, int bits, int extra,
 589               boolean boxed, boolean constant)
 590 {
 591     struct vector *vector;
 592     int nwords;
 593     lispobj result, *new;
 594
 595     vector = (struct vector *)native_pointer(thing);
 596     nwords = 2 + (CEILING((fixnum_value(vector->length)+extra)*bits,32)>>5);
 597
 598     if (boxed && !constant) {
 599         new = static_free;
 600         static_free += CEILING(nwords, 2);
 601     }
 602     else {
 603         new = read_only_free;
 604         read_only_free += CEILING(nwords, 2);
 605     }
 606
 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 __i386__
 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 *)read_only_free;
 713     read_only_free += CEILING(nwords, 2);
 714
 715     bcopy(code, new, nwords * sizeof(lispobj));
 716
 717 #ifdef LISP_FEATURE_X86
 718     apply_code_fixups_during_purify(code,new);
 719 #endif
 720
 721     result = make_lispobj(new, OTHER_POINTER_LOWTAG);
 722
 723     /* Stick in a forwarding pointer for the code object. */
 724     *(lispobj *)code = result;
 725
 726     /* Put in forwarding pointers for all the functions. */
 727     for (func = code->entry_points;
 728          func != NIL;
 729          func = ((struct simple_fun *)native_pointer(func))->next) {
 730
 731         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
 732
 733         *(lispobj *)native_pointer(func) = result + (func - thing);
 734     }
 735
 736     /* Arrange to scavenge the debug info later. */
 737     pscav_later(&new->debug_info, 1);
 738
 739     if (new->trace_table_offset & 0x3)
 740 #if 0
 741       pscav(&new->trace_table_offset, 1, 0);
 742 #else
 743       new->trace_table_offset = NIL; /* limit lifetime */
 744 #endif
 745
 746     /* Scavenge the constants. */
 747     pscav(new->constants, HeaderValue(new->header)-5, 1);
 748
 749     /* Scavenge all the functions. */
 750     pscav(&new->entry_points, 1, 1);
 751     for (func = new->entry_points;
 752          func != NIL;
 753          func = ((struct simple_fun *)native_pointer(func))->next) {
 754         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
 755         gc_assert(!dynamic_pointer_p(func));
 756
 757 #ifdef __i386__
 758         /* Temporarly convert the self pointer to a real function pointer. */
 759         ((struct simple_fun *)native_pointer(func))->self
 760             -= FUN_RAW_ADDR_OFFSET;
 761 #endif
 762         pscav(&((struct simple_fun *)native_pointer(func))->self, 2, 1);
 763 #ifdef __i386__
 764         ((struct simple_fun *)native_pointer(func))->self
 765             += FUN_RAW_ADDR_OFFSET;
 766 #endif
 767         pscav_later(&((struct simple_fun *)native_pointer(func))->name, 3);
 768     }
 769
 770     return result;
 771 }
 772
 773 static lispobj
 774 ptrans_func(lispobj thing, lispobj header)
 775 {
 776     int nwords;
 777     lispobj code, *new, *old, result;
 778     struct simple_fun *function;
 779
 780     /* Thing can either be a function header, a closure function
 781      * header, a closure, or a funcallable-instance. If it's a closure
 782      * or a funcallable-instance, we do the same as ptrans_boxed.
 783      * Otherwise we have to do something strange, 'cause it is buried
 784      * inside a code object. */
 785
 786     if (widetag_of(header) == SIMPLE_FUN_HEADER_WIDETAG ||
 787         widetag_of(header) == CLOSURE_FUN_HEADER_WIDETAG) {
 788
 789         /* We can only end up here if the code object has not been
 790          * scavenged, because if it had been scavenged, forwarding pointers
 791          * would have been left behind for all the entry points. */
 792
 793         function = (struct simple_fun *)native_pointer(thing);
 794         code =
 795             make_lispobj
 796             ((native_pointer(thing) -
 797               (HeaderValue(function->header))), OTHER_POINTER_LOWTAG);
 798
 799         /* This will cause the function's header to be replaced with a
 800          * forwarding pointer. */
 801
 802         ptrans_code(code);
 803
 804         /* So we can just return that. */
 805         return function->header;
 806     }
 807     else {
 808         /* It's some kind of closure-like thing. */
 809         nwords = 1 + HeaderValue(header);
 810         old = (lispobj *)native_pointer(thing);
 811
 812         /* Allocate the new one. */
 813         if (widetag_of(header) == FUNCALLABLE_INSTANCE_HEADER_WIDETAG) {
 814             /* FINs *must* not go in read_only space. */
 815             new = static_free;
 816             static_free += CEILING(nwords, 2);
 817         }
 818         else {
 819             /* Closures can always go in read-only space, 'cause they
 820              * never change. */
 821
 822             new = read_only_free;
 823             read_only_free += CEILING(nwords, 2);
 824         }
 825         /* Copy it. */
 826         bcopy(old, new, nwords * sizeof(lispobj));
 827
 828         /* Deposit forwarding pointer. */
 829         result = make_lispobj(new, lowtag_of(thing));
 830         *old = result;
 831
 832         /* Scavenge it. */
 833         pscav(new, nwords, 0);
 834
 835         return result;
 836     }
 837 }
 838
 839 static lispobj
 840 ptrans_returnpc(lispobj thing, lispobj header)
 841 {
 842     lispobj code, new;
 843
 844     /* Find the corresponding code object. */
 845     code = thing - HeaderValue(header)*sizeof(lispobj);
 846
 847     /* Make sure it's been transported. */
 848     new = *(lispobj *)native_pointer(code);
 849     if (!forwarding_pointer_p(new))
 850         new = ptrans_code(code);
 851
 852     /* Maintain the offset: */
 853     return new + (thing - code);
 854 }
 855
 856 #define WORDS_PER_CONS CEILING(sizeof(struct cons) / sizeof(lispobj), 2)
 857
 858 static lispobj
 859 ptrans_list(lispobj thing, boolean constant)
 860 {
 861     struct cons *old, *new, *orig;
 862     int length;
 863
 864     if (constant)
 865         orig = (struct cons *)read_only_free;
 866     else
 867         orig = (struct cons *)static_free;
 868     length = 0;
 869
 870     do {
 871         /* Allocate a new cons cell. */
 872         old = (struct cons *)native_pointer(thing);
 873         if (constant) {
 874             new = (struct cons *)read_only_free;
 875             read_only_free += WORDS_PER_CONS;
 876         }
 877         else {
 878             new = (struct cons *)static_free;
 879             static_free += WORDS_PER_CONS;
 880         }
 881
 882         /* Copy the cons cell and keep a pointer to the cdr. */
 883         new->car = old->car;
 884         thing = new->cdr = old->cdr;
 885
 886         /* Set up the forwarding pointer. */
 887         *(lispobj *)old = make_lispobj(new, LIST_POINTER_LOWTAG);
 888
 889         /* And count this cell. */
 890         length++;
 891     } while (lowtag_of(thing) == LIST_POINTER_LOWTAG &&
 892              dynamic_pointer_p(thing) &&
 893              !(forwarding_pointer_p(*(lispobj *)native_pointer(thing))));
 894
 895     /* Scavenge the list we just copied. */
 896     pscav((lispobj *)orig, length * WORDS_PER_CONS, constant);
 897
 898     return make_lispobj(orig, LIST_POINTER_LOWTAG);
 899 }
 900
 901 static lispobj
 902 ptrans_otherptr(lispobj thing, lispobj header, boolean constant)
 903 {
 904     switch (widetag_of(header)) {
 905         /* FIXME: this needs a reindent */
 906       case BIGNUM_WIDETAG:
 907       case SINGLE_FLOAT_WIDETAG:
 908       case DOUBLE_FLOAT_WIDETAG:
 909 #ifdef LONG_FLOAT_WIDETAG
 910       case LONG_FLOAT_WIDETAG:
 911 #endif
 912 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
 913       case COMPLEX_SINGLE_FLOAT_WIDETAG:
 914 #endif
 915 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
 916       case COMPLEX_DOUBLE_FLOAT_WIDETAG:
 917 #endif
 918 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
 919       case COMPLEX_LONG_FLOAT_WIDETAG:
 920 #endif
 921       case SAP_WIDETAG:
 922           return ptrans_unboxed(thing, header);
 923
 924       case RATIO_WIDETAG:
 925       case COMPLEX_WIDETAG:
 926       case SIMPLE_ARRAY_WIDETAG:
 927       case COMPLEX_BASE_STRING_WIDETAG:
 928       case COMPLEX_BIT_VECTOR_WIDETAG:
 929       case COMPLEX_VECTOR_NIL_WIDETAG:
 930       case COMPLEX_VECTOR_WIDETAG:
 931       case COMPLEX_ARRAY_WIDETAG:
 932         return ptrans_boxed(thing, header, constant);
 933
 934       case VALUE_CELL_HEADER_WIDETAG:
 935       case WEAK_POINTER_WIDETAG:
 936         return ptrans_boxed(thing, header, 0);
 937
 938       case SYMBOL_HEADER_WIDETAG:
 939         return ptrans_boxed(thing, header, 0);
 940
 941       case SIMPLE_ARRAY_NIL_WIDETAG:
 942         return ptrans_vector(thing, 0, 0, 0, constant);
 943
 944       case SIMPLE_BASE_STRING_WIDETAG:
 945         return ptrans_vector(thing, 8, 1, 0, constant);
 946
 947       case SIMPLE_BIT_VECTOR_WIDETAG:
 948         return ptrans_vector(thing, 1, 0, 0, constant);
 949
 950       case SIMPLE_VECTOR_WIDETAG:
 951         return ptrans_vector(thing, 32, 0, 1, constant);
 952
 953       case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
 954         return ptrans_vector(thing, 2, 0, 0, constant);
 955
 956       case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
 957         return ptrans_vector(thing, 4, 0, 0, constant);
 958
 959       case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
 960 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
 961       case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
 962 #endif
 963         return ptrans_vector(thing, 8, 0, 0, constant);
 964
 965       case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
 966 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
 967       case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
 968 #endif
 969         return ptrans_vector(thing, 16, 0, 0, constant);
 970
 971       case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
 972 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
 973       case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
 974 #endif
 975 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
 976       case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
 977 #endif
 978         return ptrans_vector(thing, 32, 0, 0, constant);
 979
 980       case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
 981         return ptrans_vector(thing, 32, 0, 0, constant);
 982
 983       case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
 984         return ptrans_vector(thing, 64, 0, 0, constant);
 985
 986 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
 987       case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
 988 #ifdef __i386__
 989         return ptrans_vector(thing, 96, 0, 0, constant);
 990 #endif
 991 #ifdef sparc
 992         return ptrans_vector(thing, 128, 0, 0, constant);
 993 #endif
 994 #endif
 995
 996 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
 997       case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
 998         return ptrans_vector(thing, 64, 0, 0, constant);
 999 #endif
1000
1001 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
1002       case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
1003         return ptrans_vector(thing, 128, 0, 0, constant);
1004 #endif
1005
1006 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
1007       case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
1008 #ifdef __i386__
1009         return ptrans_vector(thing, 192, 0, 0, constant);
1010 #endif
1011 #ifdef sparc
1012         return ptrans_vector(thing, 256, 0, 0, constant);
1013 #endif
1014 #endif
1015
1016       case CODE_HEADER_WIDETAG:
1017         return ptrans_code(thing);
1018
1019       case RETURN_PC_HEADER_WIDETAG:
1020         return ptrans_returnpc(thing, header);
1021
1022       case FDEFN_WIDETAG:
1023         return ptrans_fdefn(thing, header);
1024
1025       default:
1026         /* Should only come across other pointers to the above stuff. */
1027         gc_abort();
1028         return NIL;
1029     }
1030 }
1031
1032 static int
1033 pscav_fdefn(struct fdefn *fdefn)
1034 {
1035     boolean fix_func;
1036
1037     fix_func = ((char *)(fdefn->fun+FUN_RAW_ADDR_OFFSET) == fdefn->raw_addr);
1038     pscav(&fdefn->name, 1, 1);
1039     pscav(&fdefn->fun, 1, 0);
1040     if (fix_func)
1041         fdefn->raw_addr = (char *)(fdefn->fun + FUN_RAW_ADDR_OFFSET);
1042     return sizeof(struct fdefn) / sizeof(lispobj);
1043 }
1044
1045 #ifdef __i386__
1046 /* now putting code objects in static space */
1047 static int
1048 pscav_code(struct code*code)
1049 {
1050     int nwords;
1051     lispobj func;
1052     nwords = HeaderValue(code->header) + fixnum_value(code->code_size);
1053
1054     /* Arrange to scavenge the debug info later. */
1055     pscav_later(&code->debug_info, 1);
1056
1057     /* Scavenge the constants. */
1058     pscav(code->constants, HeaderValue(code->header)-5, 1);
1059
1060     /* Scavenge all the functions. */
1061     pscav(&code->entry_points, 1, 1);
1062     for (func = code->entry_points;
1063          func != NIL;
1064          func = ((struct simple_fun *)native_pointer(func))->next) {
1065         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
1066         gc_assert(!dynamic_pointer_p(func));
1067
1068 #ifdef __i386__
1069         /* Temporarily convert the self pointer to a real function
1070          * pointer. */
1071         ((struct simple_fun *)native_pointer(func))->self
1072             -= FUN_RAW_ADDR_OFFSET;
1073 #endif
1074         pscav(&((struct simple_fun *)native_pointer(func))->self, 2, 1);
1075 #ifdef __i386__
1076         ((struct simple_fun *)native_pointer(func))->self
1077             += FUN_RAW_ADDR_OFFSET;
1078 #endif
1079         pscav_later(&((struct simple_fun *)native_pointer(func))->name, 3);
1080     }
1081
1082     return CEILING(nwords,2);
1083 }
1084 #endif
1085
1086 static lispobj *
1087 pscav(lispobj *addr, int nwords, boolean constant)
1088 {
1089     lispobj thing, *thingp, header;
1090     int count = 0; /* (0 = dummy init value to stop GCC warning) */
1091     struct vector *vector;
1092
1093     while (nwords > 0) {
1094         thing = *addr;
1095         if (is_lisp_pointer(thing)) {
1096             /* It's a pointer. Is it something we might have to move? */
1097             if (dynamic_pointer_p(thing)) {
1098                 /* Maybe. Have we already moved it? */
1099                 thingp = (lispobj *)native_pointer(thing);
1100                 header = *thingp;
1101                 if (is_lisp_pointer(header) && forwarding_pointer_p(header))
1102                     /* Yep, so just copy the forwarding pointer. */
1103                     thing = header;
1104                 else {
1105                     /* Nope, copy the object. */
1106                     switch (lowtag_of(thing)) {
1107                       case FUN_POINTER_LOWTAG:
1108                         thing = ptrans_func(thing, header);
1109                         break;
1110
1111                       case LIST_POINTER_LOWTAG:
1112                         thing = ptrans_list(thing, constant);
1113                         break;
1114
1115                       case INSTANCE_POINTER_LOWTAG:
1116                         thing = ptrans_instance(thing, header, constant);
1117                         break;
1118
1119                       case OTHER_POINTER_LOWTAG:
1120                         thing = ptrans_otherptr(thing, header, constant);
1121                         break;
1122
1123                       default:
1124                         /* It was a pointer, but not one of them? */
1125                         gc_abort();
1126                     }
1127                 }
1128                 *addr = thing;
1129             }
1130             count = 1;
1131         }
1132         else if (thing & 3) {
1133             /* It's an other immediate. Maybe the header for an unboxed */
1134             /* object. */
1135             switch (widetag_of(thing)) {
1136               case BIGNUM_WIDETAG:
1137               case SINGLE_FLOAT_WIDETAG:
1138               case DOUBLE_FLOAT_WIDETAG:
1139 #ifdef LONG_FLOAT_WIDETAG
1140               case LONG_FLOAT_WIDETAG:
1141 #endif
1142               case SAP_WIDETAG:
1143                 /* It's an unboxed simple object. */
1144                 count = HeaderValue(thing)+1;
1145                 break;
1146
1147               case SIMPLE_VECTOR_WIDETAG:
1148                   if (HeaderValue(thing) == subtype_VectorValidHashing) {
1149                     *addr = (subtype_VectorMustRehash << N_WIDETAG_BITS) |
1150                         SIMPLE_VECTOR_WIDETAG;
1151                   }
1152                 count = 1;
1153                 break;
1154
1155               case SIMPLE_ARRAY_NIL_WIDETAG:
1156                 count = 2;
1157                 break;
1158
1159               case SIMPLE_BASE_STRING_WIDETAG:
1160                 vector = (struct vector *)addr;
1161                 count = CEILING(NWORDS(fixnum_value(vector->length)+1,4)+2,2);
1162                 break;
1163
1164               case SIMPLE_BIT_VECTOR_WIDETAG:
1165                 vector = (struct vector *)addr;
1166                 count = CEILING(NWORDS(fixnum_value(vector->length),32)+2,2);
1167                 break;
1168
1169               case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
1170                 vector = (struct vector *)addr;
1171                 count = CEILING(NWORDS(fixnum_value(vector->length),16)+2,2);
1172                 break;
1173
1174               case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
1175                 vector = (struct vector *)addr;
1176                 count = CEILING(NWORDS(fixnum_value(vector->length),8)+2,2);
1177                 break;
1178
1179               case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
1180 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
1181               case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
1182 #endif
1183                 vector = (struct vector *)addr;
1184                 count = CEILING(NWORDS(fixnum_value(vector->length),4)+2,2);
1185                 break;
1186
1187               case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
1188 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
1189               case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
1190 #endif
1191                 vector = (struct vector *)addr;
1192                 count = CEILING(NWORDS(fixnum_value(vector->length),2)+2,2);
1193                 break;
1194
1195               case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
1196 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
1197               case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
1198 #endif
1199 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
1200               case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
1201 #endif
1202                 vector = (struct vector *)addr;
1203                 count = CEILING(fixnum_value(vector->length)+2,2);
1204                 break;
1205
1206               case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
1207                 vector = (struct vector *)addr;
1208                 count = CEILING(fixnum_value(vector->length)+2,2);
1209                 break;
1210
1211               case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
1212 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
1213               case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
1214 #endif
1215                 vector = (struct vector *)addr;
1216                 count = fixnum_value(vector->length)*2+2;
1217                 break;
1218
1219 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
1220               case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
1221                 vector = (struct vector *)addr;
1222 #ifdef __i386__
1223                 count = fixnum_value(vector->length)*3+2;
1224 #endif
1225 #ifdef sparc
1226                 count = fixnum_value(vector->length)*4+2;
1227 #endif
1228                 break;
1229 #endif
1230
1231 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
1232               case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
1233                 vector = (struct vector *)addr;
1234                 count = fixnum_value(vector->length)*4+2;
1235                 break;
1236 #endif
1237
1238 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
1239               case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
1240                 vector = (struct vector *)addr;
1241 #ifdef __i386__
1242                 count = fixnum_value(vector->length)*6+2;
1243 #endif
1244 #ifdef sparc
1245                 count = fixnum_value(vector->length)*8+2;
1246 #endif
1247                 break;
1248 #endif
1249
1250               case CODE_HEADER_WIDETAG:
1251 #ifndef __i386__
1252                 gc_abort(); /* no code headers in static space */
1253 #else
1254                 count = pscav_code((struct code*)addr);
1255 #endif
1256                 break;
1257
1258               case SIMPLE_FUN_HEADER_WIDETAG:
1259               case CLOSURE_FUN_HEADER_WIDETAG:
1260               case RETURN_PC_HEADER_WIDETAG:
1261                 /* We should never hit any of these, 'cause they occur
1262                  * buried in the middle of code objects. */
1263                 gc_abort();
1264                 break;
1265
1266 #ifdef __i386__
1267               case CLOSURE_HEADER_WIDETAG:
1268               case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
1269                 /* The function self pointer needs special care on the
1270                  * x86 because it is the real entry point. */
1271                 {
1272                   lispobj fun = ((struct closure *)addr)->fun
1273                     - FUN_RAW_ADDR_OFFSET;
1274                   pscav(&fun, 1, constant);
1275                   ((struct closure *)addr)->fun = fun + FUN_RAW_ADDR_OFFSET;
1276                 }
1277                 count = 2;
1278                 break;
1279 #endif
1280
1281               case WEAK_POINTER_WIDETAG:
1282                 /* Weak pointers get preserved during purify, 'cause I
1283                  * don't feel like figuring out how to break them. */
1284                 pscav(addr+1, 2, constant);
1285                 count = 4;
1286                 break;
1287
1288               case FDEFN_WIDETAG:
1289                 /* We have to handle fdefn objects specially, so we
1290                  * can fix up the raw function address. */
1291                 count = pscav_fdefn((struct fdefn *)addr);
1292                 break;
1293
1294               default:
1295                 count = 1;
1296                 break;
1297             }
1298         }
1299         else {
1300             /* It's a fixnum. */
1301             count = 1;
1302         }
1303
1304         addr += count;
1305         nwords -= count;
1306     }
1307
1308     return addr;
1309 }
1310
1311 int
1312 purify(lispobj static_roots, lispobj read_only_roots)
1313 {
1314     lispobj *clean;
1315     int count, i;
1316     struct later *laters, *next;
1317     struct thread *thread;
1318
1319 #ifdef PRINTNOISE
1320     printf("[doing purification:");
1321     fflush(stdout);
1322 #endif
1323 #ifdef LISP_FEATURE_GENCGC
1324     gc_alloc_update_all_page_tables();
1325 #endif
1326     for_each_thread(thread)
1327         if (fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread)) != 0) {
1328         /* FIXME: 1. What does this mean? 2. It shouldn't be reporting
1329          * its error simply by a. printing a string b. to stdout instead
1330          * of stderr. */
1331         printf(" Ack! Can't purify interrupt contexts. ");
1332         fflush(stdout);
1333         return 0;
1334     }
1335
1336 #if defined(__i386__)
1337     dynamic_space_free_pointer =
1338       (lispobj*)SymbolValue(ALLOCATION_POINTER,0);
1339 #endif
1340
1341     read_only_end = read_only_free =
1342         (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
1343     static_end = static_free =
1344         (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
1345
1346 #ifdef PRINTNOISE
1347     printf(" roots");
1348     fflush(stdout);
1349 #endif
1350
1351 #if (defined(LISP_FEATURE_GENCGC) && defined(LISP_FEATURE_X86))
1352 #if 0
1353     /* This is what we should do, but can't unless the threads in
1354      * question are suspended with ptrace.  That's right, purify is not
1355      * threadsafe
1356      */
1357     for_each_thread(thread) {
1358         void **ptr;
1359         struct user_regs_struct regs;
1360         if(ptrace(PTRACE_GETREGS,thread->pid,0,&regs)){
1361             fprintf(stderr,"child pid %d, %s\n",thread->pid,strerror(errno));
1362             lose("PTRACE_GETREGS");
1363         }
1364         setup_i386_stack_scav(regs.ebp,
1365                               ((void *)thread->control_stack_end));
1366     }
1367 #endif /* 0 */
1368     /* stopgap until we can set things up as in preceding comment */
1369     setup_i386_stack_scav(((&static_roots)-2),
1370                           ((void *)all_threads->control_stack_end));
1371 #endif
1372
1373     pscav(&static_roots, 1, 0);
1374     pscav(&read_only_roots, 1, 1);
1375
1376 #ifdef PRINTNOISE
1377     printf(" handlers");
1378     fflush(stdout);
1379 #endif
1380     pscav((lispobj *) all_threads->interrupt_data->interrupt_handlers,
1381           sizeof(all_threads->interrupt_data->interrupt_handlers)
1382           / sizeof(lispobj),
1383           0);
1384
1385 #ifdef PRINTNOISE
1386     printf(" stack");
1387     fflush(stdout);
1388 #endif
1389 #ifndef __i386__
1390     pscav((lispobj *)all_threads->control_stack_start,
1391           current_control_stack_pointer -
1392           all_threads->control_stack_start,
1393           0);
1394 #else
1395 #ifdef LISP_FEATURE_GENCGC
1396     pscav_i386_stack();
1397 #endif
1398 #endif
1399
1400 #ifdef PRINTNOISE
1401     printf(" bindings");
1402     fflush(stdout);
1403 #endif
1404 #if !defined(__i386__)
1405     pscav( (lispobj *)all_threads->binding_stack_start,
1406           (lispobj *)current_binding_stack_pointer -
1407            all_threads->binding_stack_start,
1408           0);
1409 #else
1410     for_each_thread(thread) {
1411         pscav( (lispobj *)thread->binding_stack_start,
1412                (lispobj *)SymbolValue(BINDING_STACK_POINTER,thread) -
1413                (lispobj *)thread->binding_stack_start,
1414           0);
1415         pscav( (lispobj *) (thread+1),
1416                fixnum_value(SymbolValue(FREE_TLS_INDEX,0)) -
1417                (sizeof (struct thread))/(sizeof (lispobj)),
1418           0);
1419     }
1420
1421
1422 #endif
1423
1424     /* The original CMU CL code had scavenge-read-only-space code
1425      * controlled by the Lisp-level variable
1426      * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
1427      * wasn't documented under what circumstances it was useful or
1428      * safe to turn it on, so it's been turned off in SBCL. If you
1429      * want/need this functionality, and can test and document it,
1430      * please submit a patch. */
1431 #if 0
1432     if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != UNBOUND_MARKER_WIDETAG
1433         && SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
1434       unsigned  read_only_space_size =
1435           (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
1436           (lispobj *)READ_ONLY_SPACE_START;
1437       fprintf(stderr,
1438               "scavenging read only space: %d bytes\n",
1439               read_only_space_size * sizeof(lispobj));
1440       pscav( (lispobj *)READ_ONLY_SPACE_START, read_only_space_size, 0);
1441     }
1442 #endif
1443
1444 #ifdef PRINTNOISE
1445     printf(" static");
1446     fflush(stdout);
1447 #endif
1448     clean = (lispobj *)STATIC_SPACE_START;
1449     do {
1450         while (clean != static_free)
1451             clean = pscav(clean, static_free - clean, 0);
1452         laters = later_blocks;
1453         count = later_count;
1454         later_blocks = NULL;
1455         later_count = 0;
1456         while (laters != NULL) {
1457             for (i = 0; i < count; i++) {
1458                 if (laters->u[i].count == 0) {
1459                     ;
1460                 } else if (laters->u[i].count <= LATERMAXCOUNT) {
1461                     pscav(laters->u[i+1].ptr, laters->u[i].count, 1);
1462                     i++;
1463                 } else {
1464                     pscav(laters->u[i].ptr, 1, 1);
1465                 }
1466             }
1467             next = laters->next;
1468             free(laters);
1469             laters = next;
1470             count = LATERBLOCKSIZE;
1471         }
1472     } while (clean != static_free || later_blocks != NULL);
1473
1474 #ifdef PRINTNOISE
1475     printf(" cleanup");
1476     fflush(stdout);
1477 #endif
1478
1479     os_zero((os_vm_address_t) current_dynamic_space,
1480             (os_vm_size_t) DYNAMIC_SPACE_SIZE);
1481
1482     /* Zero the stack. Note that the stack is also zeroed by SUB-GC
1483      * calling SCRUB-CONTROL-STACK - this zeros the stack on the x86. */
1484 #ifndef __i386__
1485     os_zero((os_vm_address_t) current_control_stack_pointer,
1486             (os_vm_size_t)
1487             ((all_threads->control_stack_end -
1488               current_control_stack_pointer) * sizeof(lispobj)));
1489 #endif
1490
1491     /* It helps to update the heap free pointers so that free_heap can
1492      * verify after it's done. */
1493     SetSymbolValue(READ_ONLY_SPACE_FREE_POINTER, (lispobj)read_only_free,0);
1494     SetSymbolValue(STATIC_SPACE_FREE_POINTER, (lispobj)static_free,0);
1495
1496 #if !defined(__i386__)
1497     dynamic_space_free_pointer = current_dynamic_space;
1498     set_auto_gc_trigger(bytes_consed_between_gcs);
1499 #else
1500 #if defined LISP_FEATURE_GENCGC
1501     gc_free_heap();
1502 #else
1503 #error unsupported case /* in CMU CL, was "ibmrt using GC" */
1504 #endif
1505 #endif
1506
1507 #ifdef PRINTNOISE
1508     printf(" done]\n");
1509     fflush(stdout);
1510 #endif
1511     return 0;
1512 }