src/runtime/purify.c

   1 /*
   2  * C-level stuff to implement Lisp-level PURIFY
   3  */
   4
   5 /*
   6  * This software is part of the SBCL system. See the README file for
   7  * more information.
   8  *
   9  * This software is derived from the CMU CL system, which was
  10  * written at Carnegie Mellon University and released into the
  11  * public domain. The software is in the public domain and is
  12  * provided with absolutely no warranty. See the COPYING and CREDITS
  13  * files for more information.
  14  */
  15
  16 #include <stdio.h>
  17 #include <sys/types.h>
  18 #include <stdlib.h>
  19 #include <strings.h>
  20 #include <sys/ptrace.h>
  21 #include <linux/user.h>
  22 #include <errno.h>
  23
  24 #include "runtime.h"
  25 #include "os.h"
  26 #include "sbcl.h"
  27 #include "globals.h"
  28 #include "validate.h"
  29 #include "interrupt.h"
  30 #include "purify.h"
  31 #include "interr.h"
  32 #include "gc.h"
  33 #include "gc-internal.h"
  34 #include "thread.h"
  35 #include "genesis/primitive-objects.h"
  36 #include "genesis/static-symbols.h"
  37
  38 #define PRINTNOISE
  39
  40 #if defined(__i386__)
  41 /* again, what's so special about the x86 that this is differently
  42  * visible there than on other platforms? -dan 20010125
  43  */
  44 static lispobj *dynamic_space_free_pointer;
  45 #endif
  46
  47 #define gc_abort() \
  48   lose("GC invariant lost, file \"%s\", line %d", __FILE__, __LINE__)
  49
  50 #if 1
  51 #define gc_assert(ex) do { \
  52         if (!(ex)) gc_abort(); \
  53 } while (0)
  54 #else
  55 #define gc_assert(ex)
  56 #endif
  57
  58 \f
  59 /* These hold the original end of the read_only and static spaces so
  60  * we can tell what are forwarding pointers. */
  61
  62 static lispobj *read_only_end, *static_end;
  63
  64 static lispobj *read_only_free, *static_free;
  65
  66 static lispobj *pscav(lispobj *addr, int nwords, boolean constant);
  67
  68 #define LATERBLOCKSIZE 1020
  69 #define LATERMAXCOUNT 10
  70
  71 static struct
  72 later {
  73     struct later *next;
  74     union {
  75         lispobj *ptr;
  76         int count;
  77     } u[LATERBLOCKSIZE];
  78 } *later_blocks = NULL;
  79 static int later_count = 0;
  80
  81 #define CEILING(x,y) (((x) + ((y) - 1)) & (~((y) - 1)))
  82 #define NWORDS(x,y) (CEILING((x),(y)) / (y))
  83
  84 /* FIXME: Shouldn't this be defined in sbcl.h?  See also notes in
  85  * cheneygc.c */
  86
  87 #ifdef sparc
  88 #define FUN_RAW_ADDR_OFFSET 0
  89 #else
  90 #define FUN_RAW_ADDR_OFFSET (6*sizeof(lispobj) - FUN_POINTER_LOWTAG)
  91 #endif
  92 \f
  93 static boolean
  94 forwarding_pointer_p(lispobj obj)
  95 {
  96     lispobj *ptr = native_pointer(obj);
  97
  98     return ((static_end <= ptr && ptr <= static_free) ||
  99             (read_only_end <= ptr && ptr <= read_only_free));
 100 }
 101
 102 static boolean
 103 dynamic_pointer_p(lispobj ptr)
 104 {
 105 #ifndef __i386__
 106     return (ptr >= (lispobj)current_dynamic_space
 107             &&
 108             ptr < (lispobj)dynamic_space_free_pointer);
 109 #else
 110     /* Be more conservative, and remember, this is a maybe. */
 111     return (ptr >= (lispobj)DYNAMIC_SPACE_START
 112             &&
 113             ptr < (lispobj)dynamic_space_free_pointer);
 114 #endif
 115 }
 116
 117 \f
 118 #ifdef __i386__
 119
 120 #ifdef LISP_FEATURE_GENCGC
 121 /*
 122  * enhanced x86/GENCGC stack scavenging by Douglas Crosher
 123  *
 124  * Scavenging the stack on the i386 is problematic due to conservative
 125  * roots and raw return addresses. Here it is handled in two passes:
 126  * the first pass runs before any objects are moved and tries to
 127  * identify valid pointers and return address on the stack, the second
 128  * pass scavenges these.
 129  */
 130
 131 static unsigned pointer_filter_verbose = 0;
 132
 133 /* FIXME: This is substantially the same code as in gencgc.c. (There
 134  * are some differences, at least (1) the gencgc.c code needs to worry
 135  * about return addresses on the stack pinning code objects, (2) the
 136  * gencgc.c code needs to worry about the GC maybe happening in an
 137  * interrupt service routine when the main thread of control was
 138  * interrupted just as it had allocated memory and before it
 139  * initialized it, while PURIFY needn't worry about that, and (3) the
 140  * gencgc.c code has mutated more under maintenance since the fork
 141  * from CMU CL than the code here has.) The two versions should be
 142  * made to explicitly share common code, instead of just two different
 143  * cut-and-pasted versions. */
 144 static int
 145 valid_dynamic_space_pointer(lispobj *pointer, lispobj *start_addr)
 146 {
 147     /* If it's not a return address then it needs to be a valid Lisp
 148      * pointer. */
 149     if (!is_lisp_pointer((lispobj)pointer))
 150         return 0;
 151
 152     /* Check that the object pointed to is consistent with the pointer
 153      * low tag. */
 154     switch (lowtag_of((lispobj)pointer)) {
 155     case FUN_POINTER_LOWTAG:
 156         /* Start_addr should be the enclosing code object, or a closure
 157          * header. */
 158         switch (widetag_of(*start_addr)) {
 159         case CODE_HEADER_WIDETAG:
 160             /* This case is probably caught above. */
 161             break;
 162         case CLOSURE_HEADER_WIDETAG:
 163         case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
 164             if ((int)pointer != ((int)start_addr+FUN_POINTER_LOWTAG)) {
 165                 if (pointer_filter_verbose) {
 166                     fprintf(stderr,"*Wf2: %x %x %x\n", (unsigned int) pointer,
 167                             (unsigned int) start_addr, *start_addr);
 168                 }
 169                 return 0;
 170             }
 171             break;
 172         default:
 173             if (pointer_filter_verbose) {
 174                 fprintf(stderr,"*Wf3: %x %x %x\n", (unsigned int) pointer,
 175                         (unsigned int) start_addr, *start_addr);
 176             }
 177             return 0;
 178         }
 179         break;
 180     case LIST_POINTER_LOWTAG:
 181         if ((int)pointer != ((int)start_addr+LIST_POINTER_LOWTAG)) {
 182             if (pointer_filter_verbose)
 183                 fprintf(stderr,"*Wl1: %x %x %x\n", (unsigned int) pointer,
 184                         (unsigned int) start_addr, *start_addr);
 185             return 0;
 186         }
 187         /* Is it plausible cons? */
 188         if ((is_lisp_pointer(start_addr[0])
 189             || ((start_addr[0] & 3) == 0) /* fixnum */
 190             || (widetag_of(start_addr[0]) == BASE_CHAR_WIDETAG)
 191             || (widetag_of(start_addr[0]) == UNBOUND_MARKER_WIDETAG))
 192            && (is_lisp_pointer(start_addr[1])
 193                || ((start_addr[1] & 3) == 0) /* fixnum */
 194                || (widetag_of(start_addr[1]) == BASE_CHAR_WIDETAG)
 195                || (widetag_of(start_addr[1]) == UNBOUND_MARKER_WIDETAG))) {
 196             break;
 197         } else {
 198             if (pointer_filter_verbose) {
 199                 fprintf(stderr,"*Wl2: %x %x %x\n", (unsigned int) pointer,
 200                         (unsigned int) start_addr, *start_addr);
 201             }
 202             return 0;
 203         }
 204     case INSTANCE_POINTER_LOWTAG:
 205         if ((int)pointer != ((int)start_addr+INSTANCE_POINTER_LOWTAG)) {
 206             if (pointer_filter_verbose) {
 207                 fprintf(stderr,"*Wi1: %x %x %x\n", (unsigned int) pointer,
 208                         (unsigned int) start_addr, *start_addr);
 209             }
 210             return 0;
 211         }
 212         if (widetag_of(start_addr[0]) != INSTANCE_HEADER_WIDETAG) {
 213             if (pointer_filter_verbose) {
 214                 fprintf(stderr,"*Wi2: %x %x %x\n", (unsigned int) pointer,
 215                         (unsigned int) start_addr, *start_addr);
 216             }
 217             return 0;
 218         }
 219         break;
 220     case OTHER_POINTER_LOWTAG:
 221         if ((int)pointer != ((int)start_addr+OTHER_POINTER_LOWTAG)) {
 222             if (pointer_filter_verbose) {
 223                 fprintf(stderr,"*Wo1: %x %x %x\n", (unsigned int) pointer,
 224                         (unsigned int) start_addr, *start_addr);
 225             }
 226             return 0;
 227         }
 228         /* Is it plausible? Not a cons. XXX should check the headers. */
 229         if (is_lisp_pointer(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
 230             if (pointer_filter_verbose) {
 231                 fprintf(stderr,"*Wo2: %x %x %x\n", (unsigned int) pointer,
 232                         (unsigned int) start_addr, *start_addr);
 233             }
 234             return 0;
 235         }
 236         switch (widetag_of(start_addr[0])) {
 237         case UNBOUND_MARKER_WIDETAG:
 238         case BASE_CHAR_WIDETAG:
 239             if (pointer_filter_verbose) {
 240                 fprintf(stderr,"*Wo3: %x %x %x\n", (unsigned int) pointer,
 241                         (unsigned int) start_addr, *start_addr);
 242             }
 243             return 0;
 244
 245             /* only pointed to by function pointers? */
 246         case CLOSURE_HEADER_WIDETAG:
 247         case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
 248             if (pointer_filter_verbose) {
 249                 fprintf(stderr,"*Wo4: %x %x %x\n", (unsigned int) pointer,
 250                         (unsigned int) start_addr, *start_addr);
 251             }
 252             return 0;
 253
 254         case INSTANCE_HEADER_WIDETAG:
 255             if (pointer_filter_verbose) {
 256                 fprintf(stderr,"*Wo5: %x %x %x\n", (unsigned int) pointer,
 257                         (unsigned int) start_addr, *start_addr);
 258             }
 259             return 0;
 260
 261             /* the valid other immediate pointer objects */
 262         case SIMPLE_VECTOR_WIDETAG:
 263         case RATIO_WIDETAG:
 264         case COMPLEX_WIDETAG:
 265 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
 266         case COMPLEX_SINGLE_FLOAT_WIDETAG:
 267 #endif
 268 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
 269         case COMPLEX_DOUBLE_FLOAT_WIDETAG:
 270 #endif
 271 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
 272         case COMPLEX_LONG_FLOAT_WIDETAG:
 273 #endif
 274         case SIMPLE_ARRAY_WIDETAG:
 275         case COMPLEX_STRING_WIDETAG:
 276         case COMPLEX_BIT_VECTOR_WIDETAG:
 277         case COMPLEX_VECTOR_WIDETAG:
 278         case COMPLEX_ARRAY_WIDETAG:
 279         case VALUE_CELL_HEADER_WIDETAG:
 280         case SYMBOL_HEADER_WIDETAG:
 281         case FDEFN_WIDETAG:
 282         case CODE_HEADER_WIDETAG:
 283         case BIGNUM_WIDETAG:
 284         case SINGLE_FLOAT_WIDETAG:
 285         case DOUBLE_FLOAT_WIDETAG:
 286 #ifdef LONG_FLOAT_WIDETAG
 287         case LONG_FLOAT_WIDETAG:
 288 #endif
 289         case SIMPLE_STRING_WIDETAG:
 290         case SIMPLE_BIT_VECTOR_WIDETAG:
 291         case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
 292         case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
 293         case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
 294         case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
 295         case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
 296 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
 297         case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
 298 #endif
 299 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
 300         case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
 301 #endif
 302 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
 303         case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
 304 #endif
 305 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
 306         case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
 307 #endif
 308         case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
 309         case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
 310 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
 311         case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
 312 #endif
 313 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
 314         case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
 315 #endif
 316 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
 317         case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
 318 #endif
 319 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
 320         case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
 321 #endif
 322         case SAP_WIDETAG:
 323         case WEAK_POINTER_WIDETAG:
 324             break;
 325
 326         default:
 327             if (pointer_filter_verbose) {
 328                 fprintf(stderr,"*Wo6: %x %x %x\n", (unsigned int) pointer,
 329                         (unsigned int) start_addr, *start_addr);
 330             }
 331             return 0;
 332         }
 333         break;
 334     default:
 335         if (pointer_filter_verbose) {
 336             fprintf(stderr,"*W?: %x %x %x\n", (unsigned int) pointer,
 337                     (unsigned int) start_addr, *start_addr);
 338         }
 339         return 0;
 340     }
 341
 342     /* looks good */
 343     return 1;
 344 }
 345
 346 #define MAX_STACK_POINTERS 256
 347 lispobj *valid_stack_locations[MAX_STACK_POINTERS];
 348 unsigned int num_valid_stack_locations;
 349
 350 #define MAX_STACK_RETURN_ADDRESSES 128
 351 lispobj *valid_stack_ra_locations[MAX_STACK_RETURN_ADDRESSES];
 352 lispobj *valid_stack_ra_code_objects[MAX_STACK_RETURN_ADDRESSES];
 353 unsigned int num_valid_stack_ra_locations;
 354
 355 /* Identify valid stack slots. */
 356 static void
 357 setup_i386_stack_scav(lispobj *lowaddr, lispobj *base)
 358 {
 359     lispobj *sp = lowaddr;
 360     num_valid_stack_locations = 0;
 361     num_valid_stack_ra_locations = 0;
 362     for (sp = lowaddr; sp < base; sp++) {
 363         lispobj thing = *sp;
 364         /* Find the object start address */
 365         lispobj *start_addr = search_dynamic_space((void *)thing);
 366         if (start_addr) {
 367             /* We need to allow raw pointers into Code objects for
 368              * return addresses. This will also pick up pointers to
 369              * functions in code objects. */
 370             if (widetag_of(*start_addr) == CODE_HEADER_WIDETAG) {
 371                 /* FIXME asserting here is a really dumb thing to do.
 372                  * If we've overflowed some arbitrary static limit, we
 373                  * should just refuse to purify, instead of killing
 374                  * the whole lisp session
 375                  */
 376                 gc_assert(num_valid_stack_ra_locations <
 377                           MAX_STACK_RETURN_ADDRESSES);
 378                 valid_stack_ra_locations[num_valid_stack_ra_locations] = sp;
 379                 valid_stack_ra_code_objects[num_valid_stack_ra_locations++] =
 380                     (lispobj *)((int)start_addr + OTHER_POINTER_LOWTAG);
 381             } else {
 382                 if (valid_dynamic_space_pointer((void *)thing, start_addr)) {
 383                     gc_assert(num_valid_stack_locations < MAX_STACK_POINTERS);
 384                     valid_stack_locations[num_valid_stack_locations++] = sp;
 385                 }
 386             }
 387         }
 388     }
 389     if (pointer_filter_verbose) {
 390         fprintf(stderr, "number of valid stack pointers = %d\n",
 391                 num_valid_stack_locations);
 392         fprintf(stderr, "number of stack return addresses = %d\n",
 393                 num_valid_stack_ra_locations);
 394     }
 395 }
 396
 397 static void
 398 pscav_i386_stack(void)
 399 {
 400     int i;
 401
 402     for (i = 0; i < num_valid_stack_locations; i++)
 403         pscav(valid_stack_locations[i], 1, 0);
 404
 405     for (i = 0; i < num_valid_stack_ra_locations; i++) {
 406         lispobj code_obj = (lispobj)valid_stack_ra_code_objects[i];
 407         pscav(&code_obj, 1, 0);
 408         if (pointer_filter_verbose) {
 409             fprintf(stderr,"*C moved RA %x to %x; for code object %x to %x\n",
 410                     *valid_stack_ra_locations[i],
 411                     (int)(*valid_stack_ra_locations[i])
 412                     - ((int)valid_stack_ra_code_objects[i] - (int)code_obj),
 413                     (unsigned int) valid_stack_ra_code_objects[i], code_obj);
 414         }
 415         *valid_stack_ra_locations[i] =
 416             ((int)(*valid_stack_ra_locations[i])
 417              - ((int)valid_stack_ra_code_objects[i] - (int)code_obj));
 418     }
 419 }
 420 #endif
 421 #endif
 422
 423 \f
 424 static void
 425 pscav_later(lispobj *where, int count)
 426 {
 427     struct later *new;
 428
 429     if (count > LATERMAXCOUNT) {
 430         while (count > LATERMAXCOUNT) {
 431             pscav_later(where, LATERMAXCOUNT);
 432             count -= LATERMAXCOUNT;
 433             where += LATERMAXCOUNT;
 434         }
 435     }
 436     else {
 437         if (later_blocks == NULL || later_count == LATERBLOCKSIZE ||
 438             (later_count == LATERBLOCKSIZE-1 && count > 1)) {
 439             new  = (struct later *)malloc(sizeof(struct later));
 440             new->next = later_blocks;
 441             if (later_blocks && later_count < LATERBLOCKSIZE)
 442                 later_blocks->u[later_count].ptr = NULL;
 443             later_blocks = new;
 444             later_count = 0;
 445         }
 446
 447         if (count != 1)
 448             later_blocks->u[later_count++].count = count;
 449         later_blocks->u[later_count++].ptr = where;
 450     }
 451 }
 452
 453 static lispobj
 454 ptrans_boxed(lispobj thing, lispobj header, boolean constant)
 455 {
 456     int nwords;
 457     lispobj result, *new, *old;
 458
 459     nwords = 1 + HeaderValue(header);
 460
 461     /* Allocate it */
 462     old = (lispobj *)native_pointer(thing);
 463     if (constant) {
 464         new = read_only_free;
 465         read_only_free += CEILING(nwords, 2);
 466     }
 467     else {
 468         new = static_free;
 469         static_free += CEILING(nwords, 2);
 470     }
 471
 472     /* Copy it. */
 473     bcopy(old, new, nwords * sizeof(lispobj));
 474
 475     /* Deposit forwarding pointer. */
 476     result = make_lispobj(new, lowtag_of(thing));
 477     *old = result;
 478
 479     /* Scavenge it. */
 480     pscav(new, nwords, constant);
 481
 482     return result;
 483 }
 484
 485 /* We need to look at the layout to see whether it is a pure structure
 486  * class, and only then can we transport as constant. If it is pure,
 487  * we can ALWAYS transport as a constant. */
 488 static lispobj
 489 ptrans_instance(lispobj thing, lispobj header, boolean constant)
 490 {
 491     lispobj layout = ((struct instance *)native_pointer(thing))->slots[0];
 492     lispobj pure = ((struct instance *)native_pointer(layout))->slots[15];
 493
 494     switch (pure) {
 495     case T:
 496         return (ptrans_boxed(thing, header, 1));
 497     case NIL:
 498         return (ptrans_boxed(thing, header, 0));
 499     case 0:
 500         {
 501             /* Substructure: special case for the COMPACT-INFO-ENVs,
 502              * where the instance may have a point to the dynamic
 503              * space placed into it (e.g. the cache-name slot), but
 504              * the lists and arrays at the time of a purify can be
 505              * moved to the RO space. */
 506             int nwords;
 507             lispobj result, *new, *old;
 508
 509             nwords = 1 + HeaderValue(header);
 510
 511             /* Allocate it */
 512             old = (lispobj *)native_pointer(thing);
 513             new = static_free;
 514             static_free += CEILING(nwords, 2);
 515
 516             /* Copy it. */
 517             bcopy(old, new, nwords * sizeof(lispobj));
 518
 519             /* Deposit forwarding pointer. */
 520             result = make_lispobj(new, lowtag_of(thing));
 521             *old = result;
 522
 523             /* Scavenge it. */
 524             pscav(new, nwords, 1);
 525
 526             return result;
 527         }
 528     default:
 529         gc_abort();
 530         return NIL; /* dummy value: return something ... */
 531     }
 532 }
 533
 534 static lispobj
 535 ptrans_fdefn(lispobj thing, lispobj header)
 536 {
 537     int nwords;
 538     lispobj result, *new, *old, oldfn;
 539     struct fdefn *fdefn;
 540
 541     nwords = 1 + HeaderValue(header);
 542
 543     /* Allocate it */
 544     old = (lispobj *)native_pointer(thing);
 545     new = static_free;
 546     static_free += CEILING(nwords, 2);
 547
 548     /* Copy it. */
 549     bcopy(old, new, nwords * sizeof(lispobj));
 550
 551     /* Deposit forwarding pointer. */
 552     result = make_lispobj(new, lowtag_of(thing));
 553     *old = result;
 554
 555     /* Scavenge the function. */
 556     fdefn = (struct fdefn *)new;
 557     oldfn = fdefn->fun;
 558     pscav(&fdefn->fun, 1, 0);
 559     if ((char *)oldfn + FUN_RAW_ADDR_OFFSET == fdefn->raw_addr)
 560         fdefn->raw_addr = (char *)fdefn->fun + FUN_RAW_ADDR_OFFSET;
 561
 562     return result;
 563 }
 564
 565 static lispobj
 566 ptrans_unboxed(lispobj thing, lispobj header)
 567 {
 568     int nwords;
 569     lispobj result, *new, *old;
 570
 571     nwords = 1 + HeaderValue(header);
 572
 573     /* Allocate it */
 574     old = (lispobj *)native_pointer(thing);
 575     new = read_only_free;
 576     read_only_free += CEILING(nwords, 2);
 577
 578     /* Copy it. */
 579     bcopy(old, new, nwords * sizeof(lispobj));
 580
 581     /* Deposit forwarding pointer. */
 582     result = make_lispobj(new , lowtag_of(thing));
 583     *old = result;
 584
 585     return result;
 586 }
 587
 588 static lispobj
 589 ptrans_vector(lispobj thing, int bits, int extra,
 590               boolean boxed, boolean constant)
 591 {
 592     struct vector *vector;
 593     int nwords;
 594     lispobj result, *new;
 595
 596     vector = (struct vector *)native_pointer(thing);
 597     nwords = 2 + (CEILING((fixnum_value(vector->length)+extra)*bits,32)>>5);
 598
 599     if (boxed && !constant) {
 600         new = static_free;
 601         static_free += CEILING(nwords, 2);
 602     }
 603     else {
 604         new = read_only_free;
 605         read_only_free += CEILING(nwords, 2);
 606     }
 607
 608     bcopy(vector, new, nwords * sizeof(lispobj));
 609
 610     result = make_lispobj(new, lowtag_of(thing));
 611     vector->header = result;
 612
 613     if (boxed)
 614         pscav(new, nwords, constant);
 615
 616     return result;
 617 }
 618
 619 #ifdef __i386__
 620 static void
 621 apply_code_fixups_during_purify(struct code *old_code, struct code *new_code)
 622 {
 623     int nheader_words, ncode_words, nwords;
 624     void  *constants_start_addr, *constants_end_addr;
 625     void  *code_start_addr, *code_end_addr;
 626     lispobj fixups = NIL;
 627     unsigned  displacement = (unsigned)new_code - (unsigned)old_code;
 628     struct vector *fixups_vector;
 629
 630     ncode_words = fixnum_value(new_code->code_size);
 631     nheader_words = HeaderValue(*(lispobj *)new_code);
 632     nwords = ncode_words + nheader_words;
 633
 634     constants_start_addr = (void *)new_code + 5*4;
 635     constants_end_addr = (void *)new_code + nheader_words*4;
 636     code_start_addr = (void *)new_code + nheader_words*4;
 637     code_end_addr = (void *)new_code + nwords*4;
 638
 639     /* The first constant should be a pointer to the fixups for this
 640      * code objects. Check. */
 641     fixups = new_code->constants[0];
 642
 643     /* It will be 0 or the unbound-marker if there are no fixups, and
 644      * will be an other-pointer to a vector if it is valid. */
 645     if ((fixups==0) ||
 646         (fixups==UNBOUND_MARKER_WIDETAG) ||
 647         !is_lisp_pointer(fixups)) {
 648 #ifdef LISP_FEATURE_GENCGC
 649         /* Check for a possible errors. */
 650         sniff_code_object(new_code,displacement);
 651 #endif
 652         return;
 653     }
 654
 655     fixups_vector = (struct vector *)native_pointer(fixups);
 656
 657     /* Could be pointing to a forwarding pointer. */
 658     if (is_lisp_pointer(fixups) && (dynamic_pointer_p(fixups))
 659         && forwarding_pointer_p(*(lispobj *)fixups_vector)) {
 660         /* If so then follow it. */
 661         fixups_vector =
 662             (struct vector *)native_pointer(*(lispobj *)fixups_vector);
 663     }
 664
 665     if (widetag_of(fixups_vector->header) ==
 666         SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG) {
 667         /* We got the fixups for the code block. Now work through the
 668          * vector, and apply a fixup at each address. */
 669         int length = fixnum_value(fixups_vector->length);
 670         int i;
 671         for (i=0; i<length; i++) {
 672             unsigned offset = fixups_vector->data[i];
 673             /* Now check the current value of offset. */
 674             unsigned old_value =
 675                 *(unsigned *)((unsigned)code_start_addr + offset);
 676
 677             /* If it's within the old_code object then it must be an
 678              * absolute fixup (relative ones are not saved) */
 679             if ((old_value>=(unsigned)old_code)
 680                 && (old_value<((unsigned)old_code + nwords*4)))
 681                 /* So add the dispacement. */
 682                 *(unsigned *)((unsigned)code_start_addr + offset) = old_value
 683                     + displacement;
 684             else
 685                 /* It is outside the old code object so it must be a relative
 686                  * fixup (absolute fixups are not saved). So subtract the
 687                  * displacement. */
 688                 *(unsigned *)((unsigned)code_start_addr + offset) = old_value
 689                     - displacement;
 690         }
 691     }
 692
 693     /* No longer need the fixups. */
 694     new_code->constants[0] = 0;
 695
 696 #ifdef LISP_FEATURE_GENCGC
 697     /* Check for possible errors. */
 698     sniff_code_object(new_code,displacement);
 699 #endif
 700 }
 701 #endif
 702
 703 static lispobj
 704 ptrans_code(lispobj thing)
 705 {
 706     struct code *code, *new;
 707     int nwords;
 708     lispobj func, result;
 709
 710     code = (struct code *)native_pointer(thing);
 711     nwords = HeaderValue(code->header) + fixnum_value(code->code_size);
 712
 713     new = (struct code *)read_only_free;
 714     read_only_free += CEILING(nwords, 2);
 715
 716     bcopy(code, new, nwords * sizeof(lispobj));
 717
 718 #ifdef LISP_FEATURE_X86
 719     apply_code_fixups_during_purify(code,new);
 720 #endif
 721
 722     result = make_lispobj(new, OTHER_POINTER_LOWTAG);
 723
 724     /* Stick in a forwarding pointer for the code object. */
 725     *(lispobj *)code = result;
 726
 727     /* Put in forwarding pointers for all the functions. */
 728     for (func = code->entry_points;
 729          func != NIL;
 730          func = ((struct simple_fun *)native_pointer(func))->next) {
 731
 732         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
 733
 734         *(lispobj *)native_pointer(func) = result + (func - thing);
 735     }
 736
 737     /* Arrange to scavenge the debug info later. */
 738     pscav_later(&new->debug_info, 1);
 739
 740     if (new->trace_table_offset & 0x3)
 741 #if 0
 742       pscav(&new->trace_table_offset, 1, 0);
 743 #else
 744       new->trace_table_offset = NIL; /* limit lifetime */
 745 #endif
 746
 747     /* Scavenge the constants. */
 748     pscav(new->constants, HeaderValue(new->header)-5, 1);
 749
 750     /* Scavenge all the functions. */
 751     pscav(&new->entry_points, 1, 1);
 752     for (func = new->entry_points;
 753          func != NIL;
 754          func = ((struct simple_fun *)native_pointer(func))->next) {
 755         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
 756         gc_assert(!dynamic_pointer_p(func));
 757
 758 #ifdef __i386__
 759         /* Temporarly convert the self pointer to a real function pointer. */
 760         ((struct simple_fun *)native_pointer(func))->self
 761             -= FUN_RAW_ADDR_OFFSET;
 762 #endif
 763         pscav(&((struct simple_fun *)native_pointer(func))->self, 2, 1);
 764 #ifdef __i386__
 765         ((struct simple_fun *)native_pointer(func))->self
 766             += FUN_RAW_ADDR_OFFSET;
 767 #endif
 768         pscav_later(&((struct simple_fun *)native_pointer(func))->name, 3);
 769     }
 770
 771     return result;
 772 }
 773
 774 static lispobj
 775 ptrans_func(lispobj thing, lispobj header)
 776 {
 777     int nwords;
 778     lispobj code, *new, *old, result;
 779     struct simple_fun *function;
 780
 781     /* Thing can either be a function header, a closure function
 782      * header, a closure, or a funcallable-instance. If it's a closure
 783      * or a funcallable-instance, we do the same as ptrans_boxed.
 784      * Otherwise we have to do something strange, 'cause it is buried
 785      * inside a code object. */
 786
 787     if (widetag_of(header) == SIMPLE_FUN_HEADER_WIDETAG ||
 788         widetag_of(header) == CLOSURE_FUN_HEADER_WIDETAG) {
 789
 790         /* We can only end up here if the code object has not been
 791          * scavenged, because if it had been scavenged, forwarding pointers
 792          * would have been left behind for all the entry points. */
 793
 794         function = (struct simple_fun *)native_pointer(thing);
 795         code =
 796             make_lispobj
 797             ((native_pointer(thing) -
 798               (HeaderValue(function->header))), OTHER_POINTER_LOWTAG);
 799
 800         /* This will cause the function's header to be replaced with a
 801          * forwarding pointer. */
 802
 803         ptrans_code(code);
 804
 805         /* So we can just return that. */
 806         return function->header;
 807     }
 808     else {
 809         /* It's some kind of closure-like thing. */
 810         nwords = 1 + HeaderValue(header);
 811         old = (lispobj *)native_pointer(thing);
 812
 813         /* Allocate the new one. */
 814         if (widetag_of(header) == FUNCALLABLE_INSTANCE_HEADER_WIDETAG) {
 815             /* FINs *must* not go in read_only space. */
 816             new = static_free;
 817             static_free += CEILING(nwords, 2);
 818         }
 819         else {
 820             /* Closures can always go in read-only space, 'cause they
 821              * never change. */
 822
 823             new = read_only_free;
 824             read_only_free += CEILING(nwords, 2);
 825         }
 826         /* Copy it. */
 827         bcopy(old, new, nwords * sizeof(lispobj));
 828
 829         /* Deposit forwarding pointer. */
 830         result = make_lispobj(new, lowtag_of(thing));
 831         *old = result;
 832
 833         /* Scavenge it. */
 834         pscav(new, nwords, 0);
 835
 836         return result;
 837     }
 838 }
 839
 840 static lispobj
 841 ptrans_returnpc(lispobj thing, lispobj header)
 842 {
 843     lispobj code, new;
 844
 845     /* Find the corresponding code object. */
 846     code = thing - HeaderValue(header)*sizeof(lispobj);
 847
 848     /* Make sure it's been transported. */
 849     new = *(lispobj *)native_pointer(code);
 850     if (!forwarding_pointer_p(new))
 851         new = ptrans_code(code);
 852
 853     /* Maintain the offset: */
 854     return new + (thing - code);
 855 }
 856
 857 #define WORDS_PER_CONS CEILING(sizeof(struct cons) / sizeof(lispobj), 2)
 858
 859 static lispobj
 860 ptrans_list(lispobj thing, boolean constant)
 861 {
 862     struct cons *old, *new, *orig;
 863     int length;
 864
 865     if (constant)
 866         orig = (struct cons *)read_only_free;
 867     else
 868         orig = (struct cons *)static_free;
 869     length = 0;
 870
 871     do {
 872         /* Allocate a new cons cell. */
 873         old = (struct cons *)native_pointer(thing);
 874         if (constant) {
 875             new = (struct cons *)read_only_free;
 876             read_only_free += WORDS_PER_CONS;
 877         }
 878         else {
 879             new = (struct cons *)static_free;
 880             static_free += WORDS_PER_CONS;
 881         }
 882
 883         /* Copy the cons cell and keep a pointer to the cdr. */
 884         new->car = old->car;
 885         thing = new->cdr = old->cdr;
 886
 887         /* Set up the forwarding pointer. */
 888         *(lispobj *)old = make_lispobj(new, LIST_POINTER_LOWTAG);
 889
 890         /* And count this cell. */
 891         length++;
 892     } while (lowtag_of(thing) == LIST_POINTER_LOWTAG &&
 893              dynamic_pointer_p(thing) &&
 894              !(forwarding_pointer_p(*(lispobj *)native_pointer(thing))));
 895
 896     /* Scavenge the list we just copied. */
 897     pscav((lispobj *)orig, length * WORDS_PER_CONS, constant);
 898
 899     return make_lispobj(orig, LIST_POINTER_LOWTAG);
 900 }
 901
 902 static lispobj
 903 ptrans_otherptr(lispobj thing, lispobj header, boolean constant)
 904 {
 905     switch (widetag_of(header)) {
 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_STRING_WIDETAG:
 928       case COMPLEX_VECTOR_WIDETAG:
 929       case COMPLEX_ARRAY_WIDETAG:
 930         return ptrans_boxed(thing, header, constant);
 931
 932       case VALUE_CELL_HEADER_WIDETAG:
 933       case WEAK_POINTER_WIDETAG:
 934         return ptrans_boxed(thing, header, 0);
 935
 936       case SYMBOL_HEADER_WIDETAG:
 937         return ptrans_boxed(thing, header, 0);
 938
 939       case SIMPLE_STRING_WIDETAG:
 940         return ptrans_vector(thing, 8, 1, 0, constant);
 941
 942       case SIMPLE_BIT_VECTOR_WIDETAG:
 943         return ptrans_vector(thing, 1, 0, 0, constant);
 944
 945       case SIMPLE_VECTOR_WIDETAG:
 946         return ptrans_vector(thing, 32, 0, 1, constant);
 947
 948       case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
 949         return ptrans_vector(thing, 2, 0, 0, constant);
 950
 951       case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
 952         return ptrans_vector(thing, 4, 0, 0, constant);
 953
 954       case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
 955 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
 956       case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
 957 #endif
 958         return ptrans_vector(thing, 8, 0, 0, constant);
 959
 960       case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
 961 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
 962       case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
 963 #endif
 964         return ptrans_vector(thing, 16, 0, 0, constant);
 965
 966       case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
 967 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
 968       case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
 969 #endif
 970 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
 971       case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
 972 #endif
 973         return ptrans_vector(thing, 32, 0, 0, constant);
 974
 975       case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
 976         return ptrans_vector(thing, 32, 0, 0, constant);
 977
 978       case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
 979         return ptrans_vector(thing, 64, 0, 0, constant);
 980
 981 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
 982       case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
 983 #ifdef __i386__
 984         return ptrans_vector(thing, 96, 0, 0, constant);
 985 #endif
 986 #ifdef sparc
 987         return ptrans_vector(thing, 128, 0, 0, constant);
 988 #endif
 989 #endif
 990
 991 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
 992       case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
 993         return ptrans_vector(thing, 64, 0, 0, constant);
 994 #endif
 995
 996 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
 997       case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
 998         return ptrans_vector(thing, 128, 0, 0, constant);
 999 #endif
1000
1001 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
1002       case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
1003 #ifdef __i386__
1004         return ptrans_vector(thing, 192, 0, 0, constant);
1005 #endif
1006 #ifdef sparc
1007         return ptrans_vector(thing, 256, 0, 0, constant);
1008 #endif
1009 #endif
1010
1011       case CODE_HEADER_WIDETAG:
1012         return ptrans_code(thing);
1013
1014       case RETURN_PC_HEADER_WIDETAG:
1015         return ptrans_returnpc(thing, header);
1016
1017       case FDEFN_WIDETAG:
1018         return ptrans_fdefn(thing, header);
1019
1020       default:
1021         /* Should only come across other pointers to the above stuff. */
1022         gc_abort();
1023         return NIL;
1024     }
1025 }
1026
1027 static int
1028 pscav_fdefn(struct fdefn *fdefn)
1029 {
1030     boolean fix_func;
1031
1032     fix_func = ((char *)(fdefn->fun+FUN_RAW_ADDR_OFFSET) == fdefn->raw_addr);
1033     pscav(&fdefn->name, 1, 1);
1034     pscav(&fdefn->fun, 1, 0);
1035     if (fix_func)
1036         fdefn->raw_addr = (char *)(fdefn->fun + FUN_RAW_ADDR_OFFSET);
1037     return sizeof(struct fdefn) / sizeof(lispobj);
1038 }
1039
1040 #ifdef __i386__
1041 /* now putting code objects in static space */
1042 static int
1043 pscav_code(struct code*code)
1044 {
1045     int nwords;
1046     lispobj func;
1047     nwords = HeaderValue(code->header) + fixnum_value(code->code_size);
1048
1049     /* Arrange to scavenge the debug info later. */
1050     pscav_later(&code->debug_info, 1);
1051
1052     /* Scavenge the constants. */
1053     pscav(code->constants, HeaderValue(code->header)-5, 1);
1054
1055     /* Scavenge all the functions. */
1056     pscav(&code->entry_points, 1, 1);
1057     for (func = code->entry_points;
1058          func != NIL;
1059          func = ((struct simple_fun *)native_pointer(func))->next) {
1060         gc_assert(lowtag_of(func) == FUN_POINTER_LOWTAG);
1061         gc_assert(!dynamic_pointer_p(func));
1062
1063 #ifdef __i386__
1064         /* Temporarly convert the self pointer to a real function
1065          * pointer. */
1066         ((struct simple_fun *)native_pointer(func))->self
1067             -= FUN_RAW_ADDR_OFFSET;
1068 #endif
1069         pscav(&((struct simple_fun *)native_pointer(func))->self, 2, 1);
1070 #ifdef __i386__
1071         ((struct simple_fun *)native_pointer(func))->self
1072             += FUN_RAW_ADDR_OFFSET;
1073 #endif
1074         pscav_later(&((struct simple_fun *)native_pointer(func))->name, 3);
1075     }
1076
1077     return CEILING(nwords,2);
1078 }
1079 #endif
1080
1081 static lispobj *
1082 pscav(lispobj *addr, int nwords, boolean constant)
1083 {
1084     lispobj thing, *thingp, header;
1085     int count = 0; /* (0 = dummy init value to stop GCC warning) */
1086     struct vector *vector;
1087
1088     while (nwords > 0) {
1089         thing = *addr;
1090         if (is_lisp_pointer(thing)) {
1091             /* It's a pointer. Is it something we might have to move? */
1092             if (dynamic_pointer_p(thing)) {
1093                 /* Maybe. Have we already moved it? */
1094                 thingp = (lispobj *)native_pointer(thing);
1095                 header = *thingp;
1096                 if (is_lisp_pointer(header) && forwarding_pointer_p(header))
1097                     /* Yep, so just copy the forwarding pointer. */
1098                     thing = header;
1099                 else {
1100                     /* Nope, copy the object. */
1101                     switch (lowtag_of(thing)) {
1102                       case FUN_POINTER_LOWTAG:
1103                         thing = ptrans_func(thing, header);
1104                         break;
1105
1106                       case LIST_POINTER_LOWTAG:
1107                         thing = ptrans_list(thing, constant);
1108                         break;
1109
1110                       case INSTANCE_POINTER_LOWTAG:
1111                         thing = ptrans_instance(thing, header, constant);
1112                         break;
1113
1114                       case OTHER_POINTER_LOWTAG:
1115                         thing = ptrans_otherptr(thing, header, constant);
1116                         break;
1117
1118                       default:
1119                         /* It was a pointer, but not one of them? */
1120                         gc_abort();
1121                     }
1122                 }
1123                 *addr = thing;
1124             }
1125             count = 1;
1126         }
1127         else if (thing & 3) {
1128             /* It's an other immediate. Maybe the header for an unboxed */
1129             /* object. */
1130             switch (widetag_of(thing)) {
1131               case BIGNUM_WIDETAG:
1132               case SINGLE_FLOAT_WIDETAG:
1133               case DOUBLE_FLOAT_WIDETAG:
1134 #ifdef LONG_FLOAT_WIDETAG
1135               case LONG_FLOAT_WIDETAG:
1136 #endif
1137               case SAP_WIDETAG:
1138                 /* It's an unboxed simple object. */
1139                 count = HeaderValue(thing)+1;
1140                 break;
1141
1142               case SIMPLE_VECTOR_WIDETAG:
1143                   if (HeaderValue(thing) == subtype_VectorValidHashing) {
1144                     *addr = (subtype_VectorMustRehash << N_WIDETAG_BITS) |
1145                         SIMPLE_VECTOR_WIDETAG;
1146                   }
1147                 count = 1;
1148                 break;
1149
1150               case SIMPLE_STRING_WIDETAG:
1151                 vector = (struct vector *)addr;
1152                 count = CEILING(NWORDS(fixnum_value(vector->length)+1,4)+2,2);
1153                 break;
1154
1155               case SIMPLE_BIT_VECTOR_WIDETAG:
1156                 vector = (struct vector *)addr;
1157                 count = CEILING(NWORDS(fixnum_value(vector->length),32)+2,2);
1158                 break;
1159
1160               case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
1161                 vector = (struct vector *)addr;
1162                 count = CEILING(NWORDS(fixnum_value(vector->length),16)+2,2);
1163                 break;
1164
1165               case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
1166                 vector = (struct vector *)addr;
1167                 count = CEILING(NWORDS(fixnum_value(vector->length),8)+2,2);
1168                 break;
1169
1170               case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
1171 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
1172               case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
1173 #endif
1174                 vector = (struct vector *)addr;
1175                 count = CEILING(NWORDS(fixnum_value(vector->length),4)+2,2);
1176                 break;
1177
1178               case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
1179 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
1180               case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
1181 #endif
1182                 vector = (struct vector *)addr;
1183                 count = CEILING(NWORDS(fixnum_value(vector->length),2)+2,2);
1184                 break;
1185
1186               case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
1187 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
1188               case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
1189 #endif
1190 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
1191               case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
1192 #endif
1193                 vector = (struct vector *)addr;
1194                 count = CEILING(fixnum_value(vector->length)+2,2);
1195                 break;
1196
1197               case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
1198                 vector = (struct vector *)addr;
1199                 count = CEILING(fixnum_value(vector->length)+2,2);
1200                 break;
1201
1202               case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
1203 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
1204               case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
1205 #endif
1206                 vector = (struct vector *)addr;
1207                 count = fixnum_value(vector->length)*2+2;
1208                 break;
1209
1210 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
1211               case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
1212                 vector = (struct vector *)addr;
1213 #ifdef __i386__
1214                 count = fixnum_value(vector->length)*3+2;
1215 #endif
1216 #ifdef sparc
1217                 count = fixnum_value(vector->length)*4+2;
1218 #endif
1219                 break;
1220 #endif
1221
1222 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
1223               case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
1224                 vector = (struct vector *)addr;
1225                 count = fixnum_value(vector->length)*4+2;
1226                 break;
1227 #endif
1228
1229 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
1230               case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
1231                 vector = (struct vector *)addr;
1232 #ifdef __i386__
1233                 count = fixnum_value(vector->length)*6+2;
1234 #endif
1235 #ifdef sparc
1236                 count = fixnum_value(vector->length)*8+2;
1237 #endif
1238                 break;
1239 #endif
1240
1241               case CODE_HEADER_WIDETAG:
1242 #ifndef __i386__
1243                 gc_abort(); /* no code headers in static space */
1244 #else
1245                 count = pscav_code((struct code*)addr);
1246 #endif
1247                 break;
1248
1249               case SIMPLE_FUN_HEADER_WIDETAG:
1250               case CLOSURE_FUN_HEADER_WIDETAG:
1251               case RETURN_PC_HEADER_WIDETAG:
1252                 /* We should never hit any of these, 'cause they occur
1253                  * buried in the middle of code objects. */
1254                 gc_abort();
1255                 break;
1256
1257 #ifdef __i386__
1258               case CLOSURE_HEADER_WIDETAG:
1259               case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
1260                 /* The function self pointer needs special care on the
1261                  * x86 because it is the real entry point. */
1262                 {
1263                   lispobj fun = ((struct closure *)addr)->fun
1264                     - FUN_RAW_ADDR_OFFSET;
1265                   pscav(&fun, 1, constant);
1266                   ((struct closure *)addr)->fun = fun + FUN_RAW_ADDR_OFFSET;
1267                 }
1268                 count = 2;
1269                 break;
1270 #endif
1271
1272               case WEAK_POINTER_WIDETAG:
1273                 /* Weak pointers get preserved during purify, 'cause I
1274                  * don't feel like figuring out how to break them. */
1275                 pscav(addr+1, 2, constant);
1276                 count = 4;
1277                 break;
1278
1279               case FDEFN_WIDETAG:
1280                 /* We have to handle fdefn objects specially, so we
1281                  * can fix up the raw function address. */
1282                 count = pscav_fdefn((struct fdefn *)addr);
1283                 break;
1284
1285               default:
1286                 count = 1;
1287                 break;
1288             }
1289         }
1290         else {
1291             /* It's a fixnum. */
1292             count = 1;
1293         }
1294
1295         addr += count;
1296         nwords -= count;
1297     }
1298
1299     return addr;
1300 }
1301
1302 int
1303 purify(lispobj static_roots, lispobj read_only_roots)
1304 {
1305     lispobj *clean;
1306     int count, i;
1307     struct later *laters, *next;
1308     struct thread *thread;
1309
1310 #ifdef PRINTNOISE
1311     printf("[doing purification:");
1312     fflush(stdout);
1313 #endif
1314 #ifdef LISP_FEATURE_GENCGC
1315     gc_alloc_update_all_page_tables();
1316 #endif
1317     for_each_thread(thread)
1318         if (fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread)) != 0) {
1319         /* FIXME: 1. What does this mean? 2. It shouldn't be reporting
1320          * its error simply by a. printing a string b. to stdout instead
1321          * of stderr. */
1322         printf(" Ack! Can't purify interrupt contexts. ");
1323         fflush(stdout);
1324         return 0;
1325     }
1326
1327 #if defined(__i386__)
1328     dynamic_space_free_pointer =
1329       (lispobj*)SymbolValue(ALLOCATION_POINTER,0);
1330 #endif
1331
1332     read_only_end = read_only_free =
1333         (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
1334     static_end = static_free =
1335         (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
1336
1337 #ifdef PRINTNOISE
1338     printf(" roots");
1339     fflush(stdout);
1340 #endif
1341
1342 #if (defined(LISP_FEATURE_GENCGC) && defined(LISP_FEATURE_X86))
1343 #if 0
1344     /* This is what we should do, but can't unless the threads in
1345      * question are suspended with ptrace.  That's right, purify is not
1346      * threadsafe
1347      */
1348     for_each_thread(thread) {
1349         void **ptr;
1350         struct user_regs_struct regs;
1351         if(ptrace(PTRACE_GETREGS,thread->pid,0,&regs)){
1352             fprintf(stderr,"child pid %d, %s\n",thread->pid,strerror(errno));
1353             lose("PTRACE_GETREGS");
1354         }
1355         setup_i386_stack_scav(regs.ebp,
1356                               ((void *)thread->control_stack_end));
1357     }
1358 #endif /* 0 */
1359     /* stopgap until we can set things up as in preceding comment */
1360     setup_i386_stack_scav(((&static_roots)-2),
1361                           ((void *)all_threads->control_stack_end));
1362 #endif
1363
1364     pscav(&static_roots, 1, 0);
1365     pscav(&read_only_roots, 1, 1);
1366
1367 #ifdef PRINTNOISE
1368     printf(" handlers");
1369     fflush(stdout);
1370 #endif
1371     pscav((lispobj *) all_threads->interrupt_data->interrupt_handlers,
1372           sizeof(all_threads->interrupt_data->interrupt_handlers)
1373           / sizeof(lispobj),
1374           0);
1375
1376 #ifdef PRINTNOISE
1377     printf(" stack");
1378     fflush(stdout);
1379 #endif
1380 #ifndef __i386__
1381     pscav((lispobj *)all_threads->control_stack_start,
1382           current_control_stack_pointer -
1383           all_threads->control_stack_start,
1384           0);
1385 #else
1386 #ifdef LISP_FEATURE_GENCGC
1387     pscav_i386_stack();
1388 #endif
1389 #endif
1390
1391 #ifdef PRINTNOISE
1392     printf(" bindings");
1393     fflush(stdout);
1394 #endif
1395 #if !defined(__i386__)
1396     pscav( (lispobj *)all_threads->binding_stack_start,
1397           (lispobj *)current_binding_stack_pointer -
1398            all_threads->binding_stack_start,
1399           0);
1400 #else
1401     for_each_thread(thread) {
1402         pscav( (lispobj *)thread->binding_stack_start,
1403                (lispobj *)SymbolValue(BINDING_STACK_POINTER,thread) -
1404                (lispobj *)thread->binding_stack_start,
1405           0);
1406         pscav( (lispobj *) (thread+1),
1407                fixnum_value(SymbolValue(FREE_TLS_INDEX,0)) -
1408                (sizeof (struct thread))/(sizeof (lispobj)),
1409           0);
1410     }
1411
1412
1413 #endif
1414
1415     /* The original CMU CL code had scavenge-read-only-space code
1416      * controlled by the Lisp-level variable
1417      * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
1418      * wasn't documented under what circumstances it was useful or
1419      * safe to turn it on, so it's been turned off in SBCL. If you
1420      * want/need this functionality, and can test and document it,
1421      * please submit a patch. */
1422 #if 0
1423     if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != UNBOUND_MARKER_WIDETAG
1424         && SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
1425       unsigned  read_only_space_size =
1426           (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
1427           (lispobj *)READ_ONLY_SPACE_START;
1428       fprintf(stderr,
1429               "scavenging read only space: %d bytes\n",
1430               read_only_space_size * sizeof(lispobj));
1431       pscav( (lispobj *)READ_ONLY_SPACE_START, read_only_space_size, 0);
1432     }
1433 #endif
1434
1435 #ifdef PRINTNOISE
1436     printf(" static");
1437     fflush(stdout);
1438 #endif
1439     clean = (lispobj *)STATIC_SPACE_START;
1440     do {
1441         while (clean != static_free)
1442             clean = pscav(clean, static_free - clean, 0);
1443         laters = later_blocks;
1444         count = later_count;
1445         later_blocks = NULL;
1446         later_count = 0;
1447         while (laters != NULL) {
1448             for (i = 0; i < count; i++) {
1449                 if (laters->u[i].count == 0) {
1450                     ;
1451                 } else if (laters->u[i].count <= LATERMAXCOUNT) {
1452                     pscav(laters->u[i+1].ptr, laters->u[i].count, 1);
1453                     i++;
1454                 } else {
1455                     pscav(laters->u[i].ptr, 1, 1);
1456                 }
1457             }
1458             next = laters->next;
1459             free(laters);
1460             laters = next;
1461             count = LATERBLOCKSIZE;
1462         }
1463     } while (clean != static_free || later_blocks != NULL);
1464
1465 #ifdef PRINTNOISE
1466     printf(" cleanup");
1467     fflush(stdout);
1468 #endif
1469
1470     os_zero((os_vm_address_t) current_dynamic_space,
1471             (os_vm_size_t) DYNAMIC_SPACE_SIZE);
1472
1473     /* Zero the stack. Note that the stack is also zeroed by SUB-GC
1474      * calling SCRUB-CONTROL-STACK - this zeros the stack on the x86. */
1475 #ifndef __i386__
1476     os_zero((os_vm_address_t) current_control_stack_pointer,
1477             (os_vm_size_t) (THREAD_CONTROL_STACK_SIZE -
1478                             ((current_control_stack_pointer -
1479                               all_threads->control_stack_start)
1480                              * sizeof(lispobj))));
1481 #endif
1482
1483     /* It helps to update the heap free pointers so that free_heap can
1484      * verify after it's done. */
1485     SetSymbolValue(READ_ONLY_SPACE_FREE_POINTER, (lispobj)read_only_free,0);
1486     SetSymbolValue(STATIC_SPACE_FREE_POINTER, (lispobj)static_free,0);
1487
1488 #if !defined(__i386__)
1489     dynamic_space_free_pointer = current_dynamic_space;
1490 #else
1491 #if defined LISP_FEATURE_GENCGC
1492     gc_free_heap();
1493 #else
1494 #error unsupported case /* in CMU CL, was "ibmrt using GC" */
1495 #endif
1496 #endif
1497
1498 #ifdef PRINTNOISE
1499     printf(" done]\n");
1500     fflush(stdout);
1501 #endif
1502
1503     return 0;
1504 }