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
  49 #define gc_abort() \
  50   lose("GC invariant lost, file \"%s\", line %d", __FILE__, __LINE__)
  51
  52 #if 1
  53 #define gc_assert(ex) do { \
  54         if (!(ex)) gc_abort(); \
  55 } while (0)
  56 #else
  57 #define gc_assert(ex)
  58 #endif
  59
  60 \f
  61 /* These hold the original end of the read_only and static spaces so
  62  * we can tell what are forwarding pointers. */
  63
  64 static lispobj *read_only_end, *static_end;
  65
  66 static lispobj *read_only_free, *static_free;
  67
  68 static lispobj *pscav(lispobj *addr, int nwords, boolean constant);
  69
  70 #define LATERBLOCKSIZE 1020
  71 #define LATERMAXCOUNT 10
  72
  73 static struct
  74 later {
  75     struct later *next;
  76     union {
  77         lispobj *ptr;
  78         int count;
  79     } u[LATERBLOCKSIZE];
  80 } *later_blocks = NULL;
  81 static int later_count = 0;
  82
  83 #define CEILING(x,y) (((x) + ((y) - 1)) & (~((y) - 1)))
  84 #define NWORDS(x,y) (CEILING((x),(y)) / (y))
  85
  86 /* FIXME: Shouldn't this be defined in sbcl.h?  See also notes in
  87  * cheneygc.c */
  88
  89 #ifdef sparc
  90 #define FUN_RAW_ADDR_OFFSET 0
  91 #else
  92 #define FUN_RAW_ADDR_OFFSET (6*sizeof(lispobj) - FUN_POINTER_LOWTAG)
  93 #endif
  94 \f
  95 static boolean
  96 forwarding_pointer_p(lispobj obj)
  97 {
  98     lispobj *ptr = native_pointer(obj);
  99
 100     return ((static_end <= ptr && ptr <= static_free) ||
 101             (read_only_end <= ptr && ptr <= read_only_free));
 102 }
 103
 104 static boolean
 105 dynamic_pointer_p(lispobj ptr)
 106 {
 107 #ifndef __i386__
 108     return (ptr >= (lispobj)current_dynamic_space
 109             &&
 110             ptr < (lispobj)dynamic_space_free_pointer);
 111 #else
 112     /* Be more conservative, and remember, this is a maybe. */
 113     return (ptr >= (lispobj)DYNAMIC_SPACE_START
 114             &&
 115             ptr < (lispobj)dynamic_space_free_pointer);
 116 #endif
 117 }
 118
 119 \f
 120 #ifdef __i386__
 121
 122 #ifdef LISP_FEATURE_GENCGC
 123 /*
 124  * enhanced x86/GENCGC stack scavenging by Douglas Crosher
 125  *
 126  * Scavenging the stack on the i386 is problematic due to conservative
 127  * roots and raw return addresses. Here it is handled in two passes:
 128  * the first pass runs before any objects are moved and tries to
 129  * identify valid pointers and return address on the stack, the second
 130  * pass scavenges these.
 131  */
 132
 133 static unsigned pointer_filter_verbose = 0;
 134
 135 /* FIXME: This is substantially the same code as in gencgc.c. (There
 136  * are some differences, at least (1) the gencgc.c code needs to worry
 137  * about return addresses on the stack pinning code objects, (2) the
 138  * gencgc.c code needs to worry about the GC maybe happening in an
 139  * interrupt service routine when the main thread of control was
 140  * interrupted just as it had allocated memory and before it
 141  * initialized it, while PURIFY needn't worry about that, and (3) the
 142  * gencgc.c code has mutated more under maintenance since the fork
 143  * from CMU CL than the code here has.) The two versions should be
 144  * made to explicitly share common code, instead of just two different
 145  * cut-and-pasted versions. */
 146 static int
 147 valid_dynamic_space_pointer(lispobj *pointer, lispobj *start_addr)
 148 {
 149     /* If it's not a return address then it needs to be a valid Lisp
 150      * pointer. */
 151     if (!is_lisp_pointer((lispobj)pointer))
 152         return 0;
 153
 154     /* Check that the object pointed to is consistent with the pointer
 155      * low tag. */
 156     switch (lowtag_of((lispobj)pointer)) {
 157     case FUN_POINTER_LOWTAG:
 158         /* Start_addr should be the enclosing code object, or a closure
 159          * header. */
 160         switch (widetag_of(*start_addr)) {
 161         case CODE_HEADER_WIDETAG:
 162             /* This case is probably caught above. */
 163             break;
 164         case CLOSURE_HEADER_WIDETAG:
 165         case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
 166             if ((int)pointer != ((int)start_addr+FUN_POINTER_LOWTAG)) {
 167                 if (pointer_filter_verbose) {
 168                     fprintf(stderr,"*Wf2: %x %x %x\n", (unsigned int) pointer,
 169                             (unsigned int) start_addr, *start_addr);
 170                 }
 171                 return 0;
 172             }
 173             break;
 174         default:
 175             if (pointer_filter_verbose) {
 176                 fprintf(stderr,"*Wf3: %x %x %x\n", (unsigned int) pointer,
 177                         (unsigned int) start_addr, *start_addr);
 178             }
 179             return 0;
 180         }
 181         break;
 182     case LIST_POINTER_LOWTAG:
 183         if ((int)pointer != ((int)start_addr+LIST_POINTER_LOWTAG)) {
 184             if (pointer_filter_verbose)
 185                 fprintf(stderr,"*Wl1: %x %x %x\n", (unsigned int) pointer,
 186                         (unsigned int) start_addr, *start_addr);
 187             return 0;
 188         }
 189         /* Is it plausible cons? */
 190         if ((is_lisp_pointer(start_addr[0])
 191             || ((start_addr[0] & 3) == 0) /* fixnum */
 192             || (widetag_of(start_addr[0]) == BASE_CHAR_WIDETAG)
 193             || (widetag_of(start_addr[0]) == UNBOUND_MARKER_WIDETAG))
 194            && (is_lisp_pointer(start_addr[1])
 195                || ((start_addr[1] & 3) == 0) /* fixnum */
 196                || (widetag_of(start_addr[1]) == BASE_CHAR_WIDETAG)
 197                || (widetag_of(start_addr[1]) == UNBOUND_MARKER_WIDETAG))) {
 198             break;
 199         } else {
 200             if (pointer_filter_verbose) {
 201                 fprintf(stderr,"*Wl2: %x %x %x\n", (unsigned int) pointer,
 202                         (unsigned int) start_addr, *start_addr);
 203             }
 204             return 0;
 205         }
 206     case INSTANCE_POINTER_LOWTAG:
 207         if ((int)pointer != ((int)start_addr+INSTANCE_POINTER_LOWTAG)) {
 208             if (pointer_filter_verbose) {
 209                 fprintf(stderr,"*Wi1: %x %x %x\n", (unsigned int) pointer,
 210                         (unsigned int) start_addr, *start_addr);
 211             }
 212             return 0;
 213         }
 214         if (widetag_of(start_addr[0]) != INSTANCE_HEADER_WIDETAG) {
 215             if (pointer_filter_verbose) {
 216                 fprintf(stderr,"*Wi2: %x %x %x\n", (unsigned int) pointer,
 217                         (unsigned int) start_addr, *start_addr);
 218             }
 219             return 0;
 220         }
 221         break;
 222     case OTHER_POINTER_LOWTAG:
 223         if ((int)pointer != ((int)start_addr+OTHER_POINTER_LOWTAG)) {
 224             if (pointer_filter_verbose) {
 225                 fprintf(stderr,"*Wo1: %x %x %x\n", (unsigned int) pointer,
 226                         (unsigned int) start_addr, *start_addr);
 227             }
 228             return 0;
 229         }
 230         /* Is it plausible? Not a cons. XXX should check the headers. */
 231         if (is_lisp_pointer(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
 232             if (pointer_filter_verbose) {
 233                 fprintf(stderr,"*Wo2: %x %x %x\n", (unsigned int) pointer,
 234                         (unsigned int) start_addr, *start_addr);
 235             }
 236             return 0;
 237         }
 238         switch (widetag_of(start_addr[0])) {
 239         case UNBOUND_MARKER_WIDETAG:
 240         case BASE_CHAR_WIDETAG:
 241             if (pointer_filter_verbose) {
 242                 fprintf(stderr,"*Wo3: %x %x %x\n", (unsigned int) pointer,
 243                         (unsigned int) start_addr, *start_addr);
 244             }
 245             return 0;
 246
 247             /* only pointed to by function pointers? */
 248         case CLOSURE_HEADER_WIDETAG:
 249         case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
 250             if (pointer_filter_verbose) {
 251                 fprintf(stderr,"*Wo4: %x %x %x\n", (unsigned int) pointer,
 252                         (unsigned int) start_addr, *start_addr);
 253             }
 254             return 0;
 255
 256         case INSTANCE_HEADER_WIDETAG:
 257             if (pointer_filter_verbose) {
 258                 fprintf(stderr,"*Wo5: %x %x %x\n", (unsigned int) pointer,
 259                         (unsigned int) start_addr, *start_addr);
 260             }
 261             return 0;
 262
 263             /* the valid other immediate pointer objects */
 264         case SIMPLE_VECTOR_WIDETAG:
 265         case RATIO_WIDETAG:
 266         case COMPLEX_WIDETAG:
 267 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
 268         case COMPLEX_SINGLE_FLOAT_WIDETAG:
 269 #endif
 270 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
 271         case COMPLEX_DOUBLE_FLOAT_WIDETAG:
 272 #endif
 273 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
 274         case COMPLEX_LONG_FLOAT_WIDETAG:
 275 #endif
 276         case SIMPLE_ARRAY_WIDETAG:
 277         case COMPLEX_STRING_WIDETAG:
 278         case COMPLEX_BIT_VECTOR_WIDETAG:
 279         case COMPLEX_VECTOR_WIDETAG:
 280         case COMPLEX_ARRAY_WIDETAG:
 281         case VALUE_CELL_HEADER_WIDETAG:
 282         case SYMBOL_HEADER_WIDETAG:
 283         case FDEFN_WIDETAG:
 284         case CODE_HEADER_WIDETAG:
 285         case BIGNUM_WIDETAG:
 286         case SINGLE_FLOAT_WIDETAG:
 287         case DOUBLE_FLOAT_WIDETAG:
 288 #ifdef LONG_FLOAT_WIDETAG
 289         case LONG_FLOAT_WIDETAG:
 290 #endif
 291         case SIMPLE_STRING_WIDETAG:
 292         case SIMPLE_BIT_VECTOR_WIDETAG:
 293         case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
 294         case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
 295         case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
 296         case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
 297         case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
 298 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
 299         case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
 300 #endif
 301 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
 302         case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
 303 #endif
 304 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
 305         case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
 306 #endif
 307 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
 308         case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
 309 #endif
 310         case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
 311         case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
 312 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
 313         case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
 314 #endif
 315 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
 316         case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
 317 #endif
 318 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
 319         case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
 320 #endif
 321 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
 322         case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
 323 #endif
 324         case SAP_WIDETAG:
 325         case WEAK_POINTER_WIDETAG:
 326             break;
 327
 328         default:
 329             if (pointer_filter_verbose) {
 330                 fprintf(stderr,"*Wo6: %x %x %x\n", (unsigned int) pointer,
 331                         (unsigned int) start_addr, *start_addr);
 332             }
 333             return 0;
 334         }
 335         break;
 336     default:
 337         if (pointer_filter_verbose) {
 338             fprintf(stderr,"*W?: %x %x %x\n", (unsigned int) pointer,
 339                     (unsigned int) start_addr, *start_addr);
 340         }
 341         return 0;
 342     }
 343
 344     /* looks good */
 345     return 1;
 346 }
 347
 348 #define MAX_STACK_POINTERS 256
 349 lispobj *valid_stack_locations[MAX_STACK_POINTERS];
 350 unsigned int num_valid_stack_locations;
 351
 352 #define MAX_STACK_RETURN_ADDRESSES 128
 353 lispobj *valid_stack_ra_locations[MAX_STACK_RETURN_ADDRESSES];
 354 lispobj *valid_stack_ra_code_objects[MAX_STACK_RETURN_ADDRESSES];
 355 unsigned int num_valid_stack_ra_locations;
 356
 357 /* Identify valid stack slots. */
 358 static void
 359 setup_i386_stack_scav(lispobj *lowaddr, lispobj *base)
 360 {
 361     lispobj *sp = lowaddr;
 362     num_valid_stack_locations = 0;
 363     num_valid_stack_ra_locations = 0;
 364     for (sp = lowaddr; sp < base; sp++) {
 365         lispobj thing = *sp;
 366         /* Find the object start address */
 367         lispobj *start_addr = search_dynamic_space((void *)thing);
 368         if (start_addr) {
 369             /* We need to allow raw pointers into Code objects for
 370              * return addresses. This will also pick up pointers to
 371              * functions in code objects. */
 372             if (widetag_of(*start_addr) == CODE_HEADER_WIDETAG) {
 373                 /* FIXME asserting here is a really dumb thing to do.
 374                  * If we've overflowed some arbitrary static limit, we
 375                  * should just refuse to purify, instead of killing
 376                  * the whole lisp session
 377                  */
 378                 gc_assert(num_valid_stack_ra_locations <
 379                           MAX_STACK_RETURN_ADDRESSES);
 380                 valid_stack_ra_locations[num_valid_stack_ra_locations] = sp;
 381                 valid_stack_ra_code_objects[num_valid_stack_ra_locations++] =
 382                     (lispobj *)((int)start_addr + OTHER_POINTER_LOWTAG);
 383             } else {
 384                 if (valid_dynamic_space_pointer((void *)thing, start_addr)) {
 385                     gc_assert(num_valid_stack_locations < MAX_STACK_POINTERS);
 386                     valid_stack_locations[num_valid_stack_locations++] = sp;
 387                 }
 388             }
 389         }
 390     }
 391     if (pointer_filter_verbose) {
 392         fprintf(stderr, "number of valid stack pointers = %d\n",
 393                 num_valid_stack_locations);
 394         fprintf(stderr, "number of stack return addresses = %d\n",
 395                 num_valid_stack_ra_locations);
 396     }
 397 }
 398
 399 static void
 400 pscav_i386_stack(void)
 401 {
 402     int i;
 403
 404     for (i = 0; i < num_valid_stack_locations; i++)
 405         pscav(valid_stack_locations[i], 1, 0);
 406
 407     for (i = 0; i < num_valid_stack_ra_locations; i++) {
 408         lispobj code_obj = (lispobj)valid_stack_ra_code_objects[i];
 409         pscav(&code_obj, 1, 0);
 410         if (pointer_filter_verbose) {
 411             fprintf(stderr,"*C moved RA %x to %x; for code object %x to %x\n",
 412                     *valid_stack_ra_locations[i],
 413                     (int)(*valid_stack_ra_locations[i])
 414                     - ((int)valid_stack_ra_code_objects[i] - (int)code_obj),
 415                     (unsigned int) valid_stack_ra_code_objects[i], code_obj);
 416         }
 417         *valid_stack_ra_locations[i] =
 418             ((int)(*valid_stack_ra_locations[i])
 419              - ((int)valid_stack_ra_code_objects[i] - (int)code_obj));
 420     }
 421 }
 422 #endif
 423 #endif
 424
 425 \f
 426 static void
 427 pscav_later(lispobj *where, int count)
 428 {
 429     struct later *new;
 430
 431     if (count > LATERMAXCOUNT) {
 432         while (count > LATERMAXCOUNT) {
 433             pscav_later(where, LATERMAXCOUNT);
 434             count -= LATERMAXCOUNT;
 435             where += LATERMAXCOUNT;
 436         }
 437     }
 438     else {
 439         if (later_blocks == NULL || later_count == LATERBLOCKSIZE ||
 440             (later_count == LATERBLOCKSIZE-1 && count > 1)) {
 441             new  = (struct later *)malloc(sizeof(struct later));
 442             new->next = later_blocks;
 443             if (later_blocks && later_count < LATERBLOCKSIZE)
 444                 later_blocks->u[later_count].ptr = NULL;
 445             later_blocks = new;
 446             later_count = 0;
 447         }
 448
 449         if (count != 1)
 450             later_blocks->u[later_count++].count = count;
 451         later_blocks->u[later_count++].ptr = where;
 452     }
 453 }
 454
 455 static lispobj
 456 ptrans_boxed(lispobj thing, lispobj header, boolean constant)
 457 {
 458     int nwords;
 459     lispobj result, *new, *old;
 460
 461     nwords = 1 + HeaderValue(header);
 462
 463     /* Allocate it */
 464     old = (lispobj *)native_pointer(thing);
 465     if (constant) {
 466         new = read_only_free;
 467         read_only_free += CEILING(nwords, 2);
 468     }
 469     else {
 470         new = static_free;
 471         static_free += CEILING(nwords, 2);
 472     }
 473
 474     /* Copy it. */
 475     bcopy(old, new, nwords * sizeof(lispobj));
 476
 477     /* Deposit forwarding pointer. */
 478     result = make_lispobj(new, lowtag_of(thing));
 479     *old = result;
 480
 481     /* Scavenge it. */
 482     pscav(new, nwords, constant);
 483
 484     return result;
 485 }
 486
 487 /* We need to look at the layout to see whether it is a pure structure
 488  * class, and only then can we transport as constant. If it is pure,
 489  * we can ALWAYS transport as a constant. */
 490 static lispobj
 491 ptrans_instance(lispobj thing, lispobj header, boolean constant)
 492 {
 493     lispobj layout = ((struct instance *)native_pointer(thing))->slots[0];
 494     lispobj pure = ((struct instance *)native_pointer(layout))->slots[15];
 495
 496     switch (pure) {
 497     case T:
 498         return (ptrans_boxed(thing, header, 1));
 499     case NIL:
 500         return (ptrans_boxed(thing, header, 0));
 501     case 0:
 502         {
 503             /* Substructure: special case for the COMPACT-INFO-ENVs,
 504              * where the instance may have a point to the dynamic
 505              * space placed into it (e.g. the cache-name slot), but
 506              * the lists and arrays at the time of a purify can be
 507              * moved to the RO space. */
 508             int nwords;
 509             lispobj result, *new, *old;
 510
 511             nwords = 1 + HeaderValue(header);
 512
 513             /* Allocate it */
 514             old = (lispobj *)native_pointer(thing);
 515             new = static_free;
 516             static_free += CEILING(nwords, 2);
 517
 518             /* Copy it. */
 519             bcopy(old, new, nwords * sizeof(lispobj));
 520
 521             /* Deposit forwarding pointer. */
 522             result = make_lispobj(new, lowtag_of(thing));
 523             *old = result;
 524
 525             /* Scavenge it. */
 526             pscav(new, nwords, 1);
 527
 528             return result;
 529         }
 530     default:
 531         gc_abort();
 532         return NIL; /* dummy value: return something ... */
 533     }
 534 }
 535
 536 static lispobj
 537 ptrans_fdefn(lispobj thing, lispobj header)
 538 {
 539     int nwords;
 540     lispobj result, *new, *old, oldfn;
 541     struct fdefn *fdefn;
 542
 543     nwords = 1 + HeaderValue(header);
 544
 545     /* Allocate it */
 546     old = (lispobj *)native_pointer(thing);
 547     new = static_free;
 548     static_free += CEILING(nwords, 2);
 549
 550     /* Copy it. */
 551     bcopy(old, new, nwords * sizeof(lispobj));
 552
 553     /* Deposit forwarding pointer. */
 554     result = make_lispobj(new, lowtag_of(thing));
 555     *old = result;
 556
 557     /* Scavenge the function. */
 558     fdefn = (struct fdefn *)new;
 559     oldfn = fdefn->fun;
 560     pscav(&fdefn->fun, 1, 0);
 561     if ((char *)oldfn + FUN_RAW_ADDR_OFFSET == fdefn->raw_addr)
 562         fdefn->raw_addr = (char *)fdefn->fun + FUN_RAW_ADDR_OFFSET;
 563
 564     return result;
 565 }
 566
 567 static lispobj
 568 ptrans_unboxed(lispobj thing, lispobj header)
 569 {
 570     int nwords;
 571     lispobj result, *new, *old;
 572
 573     nwords = 1 + HeaderValue(header);
 574
 575     /* Allocate it */
 576     old = (lispobj *)native_pointer(thing);
 577     new = read_only_free;
 578     read_only_free += CEILING(nwords, 2);
 579
 580     /* Copy it. */
 581     bcopy(old, new, nwords * sizeof(lispobj));
 582
 583     /* Deposit forwarding pointer. */
 584     result = make_lispobj(new , lowtag_of(thing));
 585     *old = result;
 586
 587     return result;
 588 }
 589
 590 static lispobj
 591 ptrans_vector(lispobj thing, int bits, int extra,
 592               boolean boxed, boolean constant)
 593 {
 594     struct vector *vector;
 595     int nwords;
 596     lispobj result, *new;
 597
 598     vector = (struct vector *)native_pointer(thing);
 599     nwords = 2 + (CEILING((fixnum_value(vector->length)+extra)*bits,32)>>5);
 600
 601     if (boxed && !constant) {
 602         new = static_free;
 603         static_free += CEILING(nwords, 2);
 604     }
 605     else {
 606         new = read_only_free;
 607         read_only_free += CEILING(nwords, 2);
 608     }
 609
 610     bcopy(vector, new, nwords * sizeof(lispobj));
 611
 612     result = make_lispobj(new, lowtag_of(thing));
 613     vector->header = result;
 614
 615     if (boxed)
 616         pscav(new, nwords, constant);
 617
 618     return result;
 619 }
 620
 621 #ifdef __i386__
 622 static void
 623 apply_code_fixups_during_purify(struct code *old_code, struct code *new_code)
 624 {
 625     int nheader_words, ncode_words, nwords;
 626     void  *constants_start_addr, *constants_end_addr;
 627     void  *code_start_addr, *code_end_addr;
 628     lispobj fixups = NIL;
 629     unsigned  displacement = (unsigned)new_code - (unsigned)old_code;
 630     struct vector *fixups_vector;
 631
 632     ncode_words = fixnum_value(new_code->code_size);
 633     nheader_words = HeaderValue(*(lispobj *)new_code);
 634     nwords = ncode_words + nheader_words;
 635
 636     constants_start_addr = (void *)new_code + 5*4;
 637     constants_end_addr = (void *)new_code + nheader_words*4;
 638     code_start_addr = (void *)new_code + nheader_words*4;
 639     code_end_addr = (void *)new_code + nwords*4;
 640
 641     /* The first constant should be a pointer to the fixups for this
 642      * code objects. Check. */
 643     fixups = new_code->constants[0];
 644
 645     /* It will be 0 or the unbound-marker if there are no fixups, and
 646      * will be an other-pointer to a vector if it is valid. */
 647     if ((fixups==0) ||
 648         (fixups==UNBOUND_MARKER_WIDETAG) ||
 649         !is_lisp_pointer(fixups)) {
 650 #ifdef LISP_FEATURE_GENCGC
 651         /* Check for a possible errors. */
 652         sniff_code_object(new_code,displacement);
 653 #endif
 654         return;
 655     }
 656
 657     fixups_vector = (struct vector *)native_pointer(fixups);
 658
 659     /* Could be pointing to a forwarding pointer. */
 660     if (is_lisp_pointer(fixups) && (dynamic_pointer_p(fixups))
 661         && forwarding_pointer_p(*(lispobj *)fixups_vector)) {
 662         /* If so then follow it. */
 663         fixups_vector =
 664             (struct vector *)native_pointer(*(lispobj *)fixups_vector);
 665     }
 666
 667     if (widetag_of(fixups_vector->header) ==
 668         SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG) {
 669         /* We got the fixups for the code block. Now work through the
 670          * vector, and apply a fixup at each address. */
 671         int length = fixnum_value(fixups_vector->length);
 672         int i;
 673         for (i=0; i<length; i++) {
 674             unsigned offset = fixups_vector->data[i];
 675             /* Now check the current value of offset. */
 676             unsigned old_value =
 677                 *(unsigned *)((unsigned)code_start_addr + offset);
 678
 679             /* If it's within the old_code object then it must be an
 680              * absolute fixup (relative ones are not saved) */
 681             if ((old_value>=(unsigned)old_code)
 682                 && (old_value<((unsigned)old_code + nwords*4)))
 683                 /* So add the dispacement. */
 684                 *(unsigned *)((unsigned)code_start_addr + offset) = old_value
 685                     + displacement;
 686             else
 687                 /* It is outside the old code object so it must be a relative
 688                  * fixup (absolute fixups are not saved). So subtract the
 689                  * displacement. */
 690                 *(unsigned *)((unsigned)code_start_addr + offset) = old_value
 691                     - displacement;
 692         }
 693     }
 694
 695     /* No longer need the fixups. */
 696     new_code->constants[0] = 0;
 697
 698 #ifdef LISP_FEATURE_GENCGC
 699     /* Check for possible errors. */
 700     sniff_code_object(new_code,displacement);
 701 #endif
 702 }
 703 #endif
 704
 705 static lispobj
 706 ptrans_code(lispobj thing)
 707 {
 708     struct code *code, *new;
 709     int nwords;
 710     lispobj func, result;
 711
 712     code = (struct code *)native_pointer(thing);
 713     nwords = HeaderValue(code->header) + fixnum_value(code->code_size);
 714
 715     new = (struct code *)read_only_free;
 716     read_only_free += CEILING(nwords, 2);
 717
 718     bcopy(code, new, nwords * sizeof(lispobj));
 719
 720 #ifdef LISP_FEATURE_X86
 721     apply_code_fixups_during_purify(code,new);
 722 #endif
 723
 724     result = make_lispobj(new, OTHER_POINTER_LOWTAG);
 725
 726     /* Stick in a forwarding pointer for the code object. */
 727     *(lispobj *)code = result;
 728
 729     /* Put in forwarding pointers for all the functions. */
 730     for (func = code->entry_points;
 731          func != NIL;
 732          func = ((struct simple_fun *)native_pointer(func))->next) {
 733
 734         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
 735
 736         *(lispobj *)native_pointer(func) = result + (func - thing);
 737     }
 738
 739     /* Arrange to scavenge the debug info later. */
 740     pscav_later(&new->debug_info, 1);
 741
 742     if (new->trace_table_offset & 0x3)
 743 #if 0
 744       pscav(&new->trace_table_offset, 1, 0);
 745 #else
 746       new->trace_table_offset = NIL; /* limit lifetime */
 747 #endif
 748
 749     /* Scavenge the constants. */
 750     pscav(new->constants, HeaderValue(new->header)-5, 1);
 751
 752     /* Scavenge all the functions. */
 753     pscav(&new->entry_points, 1, 1);
 754     for (func = new->entry_points;
 755          func != NIL;
 756          func = ((struct simple_fun *)native_pointer(func))->next) {
 757         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
 758         gc_assert(!dynamic_pointer_p(func));
 759
 760 #ifdef __i386__
 761         /* Temporarly convert the self pointer to a real function pointer. */
 762         ((struct simple_fun *)native_pointer(func))->self
 763             -= FUN_RAW_ADDR_OFFSET;
 764 #endif
 765         pscav(&((struct simple_fun *)native_pointer(func))->self, 2, 1);
 766 #ifdef __i386__
 767         ((struct simple_fun *)native_pointer(func))->self
 768             += FUN_RAW_ADDR_OFFSET;
 769 #endif
 770         pscav_later(&((struct simple_fun *)native_pointer(func))->name, 3);
 771     }
 772
 773     return result;
 774 }
 775
 776 static lispobj
 777 ptrans_func(lispobj thing, lispobj header)
 778 {
 779     int nwords;
 780     lispobj code, *new, *old, result;
 781     struct simple_fun *function;
 782
 783     /* Thing can either be a function header, a closure function
 784      * header, a closure, or a funcallable-instance. If it's a closure
 785      * or a funcallable-instance, we do the same as ptrans_boxed.
 786      * Otherwise we have to do something strange, 'cause it is buried
 787      * inside a code object. */
 788
 789     if (widetag_of(header) == SIMPLE_FUN_HEADER_WIDETAG ||
 790         widetag_of(header) == CLOSURE_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. */
 816         if (widetag_of(header) == FUNCALLABLE_INSTANCE_HEADER_WIDETAG) {
 817             /* FINs *must* not go in read_only space. */
 818             new = static_free;
 819             static_free += CEILING(nwords, 2);
 820         }
 821         else {
 822             /* Closures can always go in read-only space, 'cause they
 823              * never change. */
 824
 825             new = read_only_free;
 826             read_only_free += CEILING(nwords, 2);
 827         }
 828         /* Copy it. */
 829         bcopy(old, new, nwords * sizeof(lispobj));
 830
 831         /* Deposit forwarding pointer. */
 832         result = make_lispobj(new, lowtag_of(thing));
 833         *old = result;
 834
 835         /* Scavenge it. */
 836         pscav(new, nwords, 0);
 837
 838         return result;
 839     }
 840 }
 841
 842 static lispobj
 843 ptrans_returnpc(lispobj thing, lispobj header)
 844 {
 845     lispobj code, new;
 846
 847     /* Find the corresponding code object. */
 848     code = thing - HeaderValue(header)*sizeof(lispobj);
 849
 850     /* Make sure it's been transported. */
 851     new = *(lispobj *)native_pointer(code);
 852     if (!forwarding_pointer_p(new))
 853         new = ptrans_code(code);
 854
 855     /* Maintain the offset: */
 856     return new + (thing - code);
 857 }
 858
 859 #define WORDS_PER_CONS CEILING(sizeof(struct cons) / sizeof(lispobj), 2)
 860
 861 static lispobj
 862 ptrans_list(lispobj thing, boolean constant)
 863 {
 864     struct cons *old, *new, *orig;
 865     int length;
 866
 867     if (constant)
 868         orig = (struct cons *)read_only_free;
 869     else
 870         orig = (struct cons *)static_free;
 871     length = 0;
 872
 873     do {
 874         /* Allocate a new cons cell. */
 875         old = (struct cons *)native_pointer(thing);
 876         if (constant) {
 877             new = (struct cons *)read_only_free;
 878             read_only_free += WORDS_PER_CONS;
 879         }
 880         else {
 881             new = (struct cons *)static_free;
 882             static_free += WORDS_PER_CONS;
 883         }
 884
 885         /* Copy the cons cell and keep a pointer to the cdr. */
 886         new->car = old->car;
 887         thing = new->cdr = old->cdr;
 888
 889         /* Set up the forwarding pointer. */
 890         *(lispobj *)old = make_lispobj(new, LIST_POINTER_LOWTAG);
 891
 892         /* And count this cell. */
 893         length++;
 894     } while (lowtag_of(thing) == LIST_POINTER_LOWTAG &&
 895              dynamic_pointer_p(thing) &&
 896              !(forwarding_pointer_p(*(lispobj *)native_pointer(thing))));
 897
 898     /* Scavenge the list we just copied. */
 899     pscav((lispobj *)orig, length * WORDS_PER_CONS, constant);
 900
 901     return make_lispobj(orig, LIST_POINTER_LOWTAG);
 902 }
 903
 904 static lispobj
 905 ptrans_otherptr(lispobj thing, lispobj header, boolean constant)
 906 {
 907     switch (widetag_of(header)) {
 908       case BIGNUM_WIDETAG:
 909       case SINGLE_FLOAT_WIDETAG:
 910       case DOUBLE_FLOAT_WIDETAG:
 911 #ifdef LONG_FLOAT_WIDETAG
 912       case LONG_FLOAT_WIDETAG:
 913 #endif
 914 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
 915       case COMPLEX_SINGLE_FLOAT_WIDETAG:
 916 #endif
 917 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
 918       case COMPLEX_DOUBLE_FLOAT_WIDETAG:
 919 #endif
 920 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
 921       case COMPLEX_LONG_FLOAT_WIDETAG:
 922 #endif
 923       case SAP_WIDETAG:
 924         return ptrans_unboxed(thing, header);
 925
 926       case RATIO_WIDETAG:
 927       case COMPLEX_WIDETAG:
 928       case SIMPLE_ARRAY_WIDETAG:
 929       case COMPLEX_STRING_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_STRING_WIDETAG:
 942         return ptrans_vector(thing, 8, 1, 0, constant);
 943
 944       case SIMPLE_BIT_VECTOR_WIDETAG:
 945         return ptrans_vector(thing, 1, 0, 0, constant);
 946
 947       case SIMPLE_VECTOR_WIDETAG:
 948         return ptrans_vector(thing, 32, 0, 1, constant);
 949
 950       case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
 951         return ptrans_vector(thing, 2, 0, 0, constant);
 952
 953       case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
 954         return ptrans_vector(thing, 4, 0, 0, constant);
 955
 956       case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
 957 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
 958       case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
 959 #endif
 960         return ptrans_vector(thing, 8, 0, 0, constant);
 961
 962       case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
 963 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
 964       case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
 965 #endif
 966         return ptrans_vector(thing, 16, 0, 0, constant);
 967
 968       case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
 969 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
 970       case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
 971 #endif
 972 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
 973       case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
 974 #endif
 975         return ptrans_vector(thing, 32, 0, 0, constant);
 976
 977       case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
 978         return ptrans_vector(thing, 32, 0, 0, constant);
 979
 980       case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
 981         return ptrans_vector(thing, 64, 0, 0, constant);
 982
 983 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
 984       case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
 985 #ifdef __i386__
 986         return ptrans_vector(thing, 96, 0, 0, constant);
 987 #endif
 988 #ifdef sparc
 989         return ptrans_vector(thing, 128, 0, 0, constant);
 990 #endif
 991 #endif
 992
 993 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
 994       case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
 995         return ptrans_vector(thing, 64, 0, 0, constant);
 996 #endif
 997
 998 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
 999       case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
1000         return ptrans_vector(thing, 128, 0, 0, constant);
1001 #endif
1002
1003 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
1004       case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
1005 #ifdef __i386__
1006         return ptrans_vector(thing, 192, 0, 0, constant);
1007 #endif
1008 #ifdef sparc
1009         return ptrans_vector(thing, 256, 0, 0, constant);
1010 #endif
1011 #endif
1012
1013       case CODE_HEADER_WIDETAG:
1014         return ptrans_code(thing);
1015
1016       case RETURN_PC_HEADER_WIDETAG:
1017         return ptrans_returnpc(thing, header);
1018
1019       case FDEFN_WIDETAG:
1020         return ptrans_fdefn(thing, header);
1021
1022       default:
1023         /* Should only come across other pointers to the above stuff. */
1024         gc_abort();
1025         return NIL;
1026     }
1027 }
1028
1029 static int
1030 pscav_fdefn(struct fdefn *fdefn)
1031 {
1032     boolean fix_func;
1033
1034     fix_func = ((char *)(fdefn->fun+FUN_RAW_ADDR_OFFSET) == fdefn->raw_addr);
1035     pscav(&fdefn->name, 1, 1);
1036     pscav(&fdefn->fun, 1, 0);
1037     if (fix_func)
1038         fdefn->raw_addr = (char *)(fdefn->fun + FUN_RAW_ADDR_OFFSET);
1039     return sizeof(struct fdefn) / sizeof(lispobj);
1040 }
1041
1042 #ifdef __i386__
1043 /* now putting code objects in static space */
1044 static int
1045 pscav_code(struct code*code)
1046 {
1047     int nwords;
1048     lispobj func;
1049     nwords = HeaderValue(code->header) + fixnum_value(code->code_size);
1050
1051     /* Arrange to scavenge the debug info later. */
1052     pscav_later(&code->debug_info, 1);
1053
1054     /* Scavenge the constants. */
1055     pscav(code->constants, HeaderValue(code->header)-5, 1);
1056
1057     /* Scavenge all the functions. */
1058     pscav(&code->entry_points, 1, 1);
1059     for (func = code->entry_points;
1060          func != NIL;
1061          func = ((struct simple_fun *)native_pointer(func))->next) {
1062         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
1063         gc_assert(!dynamic_pointer_p(func));
1064
1065 #ifdef __i386__
1066         /* Temporarly convert the self pointer to a real function
1067          * pointer. */
1068         ((struct simple_fun *)native_pointer(func))->self
1069             -= FUN_RAW_ADDR_OFFSET;
1070 #endif
1071         pscav(&((struct simple_fun *)native_pointer(func))->self, 2, 1);
1072 #ifdef __i386__
1073         ((struct simple_fun *)native_pointer(func))->self
1074             += FUN_RAW_ADDR_OFFSET;
1075 #endif
1076         pscav_later(&((struct simple_fun *)native_pointer(func))->name, 3);
1077     }
1078
1079     return CEILING(nwords,2);
1080 }
1081 #endif
1082
1083 static lispobj *
1084 pscav(lispobj *addr, int nwords, boolean constant)
1085 {
1086     lispobj thing, *thingp, header;
1087     int count = 0; /* (0 = dummy init value to stop GCC warning) */
1088     struct vector *vector;
1089
1090     while (nwords > 0) {
1091         thing = *addr;
1092         if (is_lisp_pointer(thing)) {
1093             /* It's a pointer. Is it something we might have to move? */
1094             if (dynamic_pointer_p(thing)) {
1095                 /* Maybe. Have we already moved it? */
1096                 thingp = (lispobj *)native_pointer(thing);
1097                 header = *thingp;
1098                 if (is_lisp_pointer(header) && forwarding_pointer_p(header))
1099                     /* Yep, so just copy the forwarding pointer. */
1100                     thing = header;
1101                 else {
1102                     /* Nope, copy the object. */
1103                     switch (lowtag_of(thing)) {
1104                       case FUN_POINTER_LOWTAG:
1105                         thing = ptrans_func(thing, header);
1106                         break;
1107
1108                       case LIST_POINTER_LOWTAG:
1109                         thing = ptrans_list(thing, constant);
1110                         break;
1111
1112                       case INSTANCE_POINTER_LOWTAG:
1113                         thing = ptrans_instance(thing, header, constant);
1114                         break;
1115
1116                       case OTHER_POINTER_LOWTAG:
1117                         thing = ptrans_otherptr(thing, header, constant);
1118                         break;
1119
1120                       default:
1121                         /* It was a pointer, but not one of them? */
1122                         gc_abort();
1123                     }
1124                 }
1125                 *addr = thing;
1126             }
1127             count = 1;
1128         }
1129         else if (thing & 3) {
1130             /* It's an other immediate. Maybe the header for an unboxed */
1131             /* object. */
1132             switch (widetag_of(thing)) {
1133               case BIGNUM_WIDETAG:
1134               case SINGLE_FLOAT_WIDETAG:
1135               case DOUBLE_FLOAT_WIDETAG:
1136 #ifdef LONG_FLOAT_WIDETAG
1137               case LONG_FLOAT_WIDETAG:
1138 #endif
1139               case SAP_WIDETAG:
1140                 /* It's an unboxed simple object. */
1141                 count = HeaderValue(thing)+1;
1142                 break;
1143
1144               case SIMPLE_VECTOR_WIDETAG:
1145                   if (HeaderValue(thing) == subtype_VectorValidHashing) {
1146                     *addr = (subtype_VectorMustRehash << N_WIDETAG_BITS) |
1147                         SIMPLE_VECTOR_WIDETAG;
1148                   }
1149                 count = 1;
1150                 break;
1151
1152               case SIMPLE_STRING_WIDETAG:
1153                 vector = (struct vector *)addr;
1154                 count = CEILING(NWORDS(fixnum_value(vector->length)+1,4)+2,2);
1155                 break;
1156
1157               case SIMPLE_BIT_VECTOR_WIDETAG:
1158                 vector = (struct vector *)addr;
1159                 count = CEILING(NWORDS(fixnum_value(vector->length),32)+2,2);
1160                 break;
1161
1162               case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
1163                 vector = (struct vector *)addr;
1164                 count = CEILING(NWORDS(fixnum_value(vector->length),16)+2,2);
1165                 break;
1166
1167               case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
1168                 vector = (struct vector *)addr;
1169                 count = CEILING(NWORDS(fixnum_value(vector->length),8)+2,2);
1170                 break;
1171
1172               case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
1173 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
1174               case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
1175 #endif
1176                 vector = (struct vector *)addr;
1177                 count = CEILING(NWORDS(fixnum_value(vector->length),4)+2,2);
1178                 break;
1179
1180               case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
1181 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
1182               case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
1183 #endif
1184                 vector = (struct vector *)addr;
1185                 count = CEILING(NWORDS(fixnum_value(vector->length),2)+2,2);
1186                 break;
1187
1188               case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
1189 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
1190               case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
1191 #endif
1192 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
1193               case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
1194 #endif
1195                 vector = (struct vector *)addr;
1196                 count = CEILING(fixnum_value(vector->length)+2,2);
1197                 break;
1198
1199               case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
1200                 vector = (struct vector *)addr;
1201                 count = CEILING(fixnum_value(vector->length)+2,2);
1202                 break;
1203
1204               case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
1205 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
1206               case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
1207 #endif
1208                 vector = (struct vector *)addr;
1209                 count = fixnum_value(vector->length)*2+2;
1210                 break;
1211
1212 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
1213               case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
1214                 vector = (struct vector *)addr;
1215 #ifdef __i386__
1216                 count = fixnum_value(vector->length)*3+2;
1217 #endif
1218 #ifdef sparc
1219                 count = fixnum_value(vector->length)*4+2;
1220 #endif
1221                 break;
1222 #endif
1223
1224 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
1225               case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
1226                 vector = (struct vector *)addr;
1227                 count = fixnum_value(vector->length)*4+2;
1228                 break;
1229 #endif
1230
1231 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
1232               case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
1233                 vector = (struct vector *)addr;
1234 #ifdef __i386__
1235                 count = fixnum_value(vector->length)*6+2;
1236 #endif
1237 #ifdef sparc
1238                 count = fixnum_value(vector->length)*8+2;
1239 #endif
1240                 break;
1241 #endif
1242
1243               case CODE_HEADER_WIDETAG:
1244 #ifndef __i386__
1245                 gc_abort(); /* no code headers in static space */
1246 #else
1247                 count = pscav_code((struct code*)addr);
1248 #endif
1249                 break;
1250
1251               case SIMPLE_FUN_HEADER_WIDETAG:
1252               case CLOSURE_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 __i386__
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 #ifdef PRINTNOISE
1313     printf("[doing purification:");
1314     fflush(stdout);
1315 #endif
1316 #ifdef LISP_FEATURE_GENCGC
1317     gc_alloc_update_all_page_tables();
1318 #endif
1319     for_each_thread(thread)
1320         if (fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread)) != 0) {
1321         /* FIXME: 1. What does this mean? 2. It shouldn't be reporting
1322          * its error simply by a. printing a string b. to stdout instead
1323          * of stderr. */
1324         printf(" Ack! Can't purify interrupt contexts. ");
1325         fflush(stdout);
1326         return 0;
1327     }
1328
1329 #if defined(__i386__)
1330     dynamic_space_free_pointer =
1331       (lispobj*)SymbolValue(ALLOCATION_POINTER,0);
1332 #endif
1333
1334     read_only_end = read_only_free =
1335         (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
1336     static_end = static_free =
1337         (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
1338
1339 #ifdef PRINTNOISE
1340     printf(" roots");
1341     fflush(stdout);
1342 #endif
1343
1344 #if (defined(LISP_FEATURE_GENCGC) && defined(LISP_FEATURE_X86))
1345 #if 0
1346     /* This is what we should do, but can't unless the threads in
1347      * question are suspended with ptrace.  That's right, purify is not
1348      * threadsafe
1349      */
1350     for_each_thread(thread) {
1351         void **ptr;
1352         struct user_regs_struct regs;
1353         if(ptrace(PTRACE_GETREGS,thread->pid,0,&regs)){
1354             fprintf(stderr,"child pid %d, %s\n",thread->pid,strerror(errno));
1355             lose("PTRACE_GETREGS");
1356         }
1357         setup_i386_stack_scav(regs.ebp,
1358                               ((void *)thread->control_stack_end));
1359     }
1360 #endif /* 0 */
1361     /* stopgap until we can set things up as in preceding comment */
1362     setup_i386_stack_scav(((&static_roots)-2),
1363                           ((void *)all_threads->control_stack_end));
1364 #endif
1365
1366     pscav(&static_roots, 1, 0);
1367     pscav(&read_only_roots, 1, 1);
1368
1369 #ifdef PRINTNOISE
1370     printf(" handlers");
1371     fflush(stdout);
1372 #endif
1373     pscav((lispobj *) all_threads->interrupt_data->interrupt_handlers,
1374           sizeof(all_threads->interrupt_data->interrupt_handlers)
1375           / sizeof(lispobj),
1376           0);
1377
1378 #ifdef PRINTNOISE
1379     printf(" stack");
1380     fflush(stdout);
1381 #endif
1382 #ifndef __i386__
1383     pscav((lispobj *)all_threads->control_stack_start,
1384           current_control_stack_pointer -
1385           all_threads->control_stack_start,
1386           0);
1387 #else
1388 #ifdef LISP_FEATURE_GENCGC
1389     pscav_i386_stack();
1390 #endif
1391 #endif
1392
1393 #ifdef PRINTNOISE
1394     printf(" bindings");
1395     fflush(stdout);
1396 #endif
1397 #if !defined(__i386__)
1398     pscav( (lispobj *)all_threads->binding_stack_start,
1399           (lispobj *)current_binding_stack_pointer -
1400            all_threads->binding_stack_start,
1401           0);
1402 #else
1403     for_each_thread(thread) {
1404         pscav( (lispobj *)thread->binding_stack_start,
1405                (lispobj *)SymbolValue(BINDING_STACK_POINTER,thread) -
1406                (lispobj *)thread->binding_stack_start,
1407           0);
1408         pscav( (lispobj *) (thread+1),
1409                fixnum_value(SymbolValue(FREE_TLS_INDEX,0)) -
1410                (sizeof (struct thread))/(sizeof (lispobj)),
1411           0);
1412     }
1413
1414
1415 #endif
1416
1417     /* The original CMU CL code had scavenge-read-only-space code
1418      * controlled by the Lisp-level variable
1419      * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
1420      * wasn't documented under what circumstances it was useful or
1421      * safe to turn it on, so it's been turned off in SBCL. If you
1422      * want/need this functionality, and can test and document it,
1423      * please submit a patch. */
1424 #if 0
1425     if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != UNBOUND_MARKER_WIDETAG
1426         && SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
1427       unsigned  read_only_space_size =
1428           (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
1429           (lispobj *)READ_ONLY_SPACE_START;
1430       fprintf(stderr,
1431               "scavenging read only space: %d bytes\n",
1432               read_only_space_size * sizeof(lispobj));
1433       pscav( (lispobj *)READ_ONLY_SPACE_START, read_only_space_size, 0);
1434     }
1435 #endif
1436
1437 #ifdef PRINTNOISE
1438     printf(" static");
1439     fflush(stdout);
1440 #endif
1441     clean = (lispobj *)STATIC_SPACE_START;
1442     do {
1443         while (clean != static_free)
1444             clean = pscav(clean, static_free - clean, 0);
1445         laters = later_blocks;
1446         count = later_count;
1447         later_blocks = NULL;
1448         later_count = 0;
1449         while (laters != NULL) {
1450             for (i = 0; i < count; i++) {
1451                 if (laters->u[i].count == 0) {
1452                     ;
1453                 } else if (laters->u[i].count <= LATERMAXCOUNT) {
1454                     pscav(laters->u[i+1].ptr, laters->u[i].count, 1);
1455                     i++;
1456                 } else {
1457                     pscav(laters->u[i].ptr, 1, 1);
1458                 }
1459             }
1460             next = laters->next;
1461             free(laters);
1462             laters = next;
1463             count = LATERBLOCKSIZE;
1464         }
1465     } while (clean != static_free || later_blocks != NULL);
1466
1467 #ifdef PRINTNOISE
1468     printf(" cleanup");
1469     fflush(stdout);
1470 #endif
1471
1472     os_zero((os_vm_address_t) current_dynamic_space,
1473             (os_vm_size_t) DYNAMIC_SPACE_SIZE);
1474
1475     /* Zero the stack. Note that the stack is also zeroed by SUB-GC
1476      * calling SCRUB-CONTROL-STACK - this zeros the stack on the x86. */
1477 #ifndef __i386__
1478     os_zero((os_vm_address_t) current_control_stack_pointer,
1479             (os_vm_size_t)
1480             ((all_threads->control_stack_end -
1481               current_control_stack_pointer) * sizeof(lispobj)));
1482 #endif
1483
1484     /* It helps to update the heap free pointers so that free_heap can
1485      * verify after it's done. */
1486     SetSymbolValue(READ_ONLY_SPACE_FREE_POINTER, (lispobj)read_only_free,0);
1487     SetSymbolValue(STATIC_SPACE_FREE_POINTER, (lispobj)static_free,0);
1488
1489 #if !defined(__i386__)
1490     dynamic_space_free_pointer = current_dynamic_space;
1491 #else
1492 #if defined LISP_FEATURE_GENCGC
1493     gc_free_heap();
1494 #else
1495 #error unsupported case /* in CMU CL, was "ibmrt using GC" */
1496 #endif
1497 #endif
1498
1499 #ifdef PRINTNOISE
1500     printf(" done]\n");
1501     fflush(stdout);
1502 #endif
1503
1504     return 0;
1505 }