Annotation of OpenXM_contrib/gc/mark.c, Revision 1.1
1.1 ! maekawa 1:
! 2: /*
! 3: * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
! 4: * Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved.
! 5: *
! 6: * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
! 7: * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
! 8: *
! 9: * Permission is hereby granted to use or copy this program
! 10: * for any purpose, provided the above notices are retained on all copies.
! 11: * Permission to modify the code and to distribute modified code is granted,
! 12: * provided the above notices are retained, and a notice that the code was
! 13: * modified is included with the above copyright notice.
! 14: *
! 15: */
! 16:
! 17:
! 18: # include <stdio.h>
! 19: # include "gc_priv.h"
! 20: # include "gc_mark.h"
! 21:
! 22: /* We put this here to minimize the risk of inlining. */
! 23: /*VARARGS*/
! 24: #ifdef __WATCOMC__
! 25: void GC_noop(void *p, ...) {}
! 26: #else
! 27: void GC_noop() {}
! 28: #endif
! 29:
! 30: /* Single argument version, robust against whole program analysis. */
! 31: void GC_noop1(x)
! 32: word x;
! 33: {
! 34: static VOLATILE word sink;
! 35:
! 36: sink = x;
! 37: }
! 38:
! 39: /* mark_proc GC_mark_procs[MAX_MARK_PROCS] = {0} -- declared in gc_priv.h */
! 40:
! 41: word GC_n_mark_procs = 0;
! 42:
! 43: /* Initialize GC_obj_kinds properly and standard free lists properly. */
! 44: /* This must be done statically since they may be accessed before */
! 45: /* GC_init is called. */
! 46: /* It's done here, since we need to deal with mark descriptors. */
! 47: struct obj_kind GC_obj_kinds[MAXOBJKINDS] = {
! 48: /* PTRFREE */ { &GC_aobjfreelist[0], 0 /* filled in dynamically */,
! 49: 0 | DS_LENGTH, FALSE, FALSE },
! 50: /* NORMAL */ { &GC_objfreelist[0], 0,
! 51: # if defined(ADD_BYTE_AT_END) && ALIGNMENT > DS_TAGS
! 52: (word)(-ALIGNMENT) | DS_LENGTH,
! 53: # else
! 54: 0 | DS_LENGTH,
! 55: # endif
! 56: TRUE /* add length to descr */, TRUE },
! 57: /* UNCOLLECTABLE */
! 58: { &GC_uobjfreelist[0], 0,
! 59: 0 | DS_LENGTH, TRUE /* add length to descr */, TRUE },
! 60: # ifdef ATOMIC_UNCOLLECTABLE
! 61: /* AUNCOLLECTABLE */
! 62: { &GC_auobjfreelist[0], 0,
! 63: 0 | DS_LENGTH, FALSE /* add length to descr */, FALSE },
! 64: # endif
! 65: # ifdef STUBBORN_ALLOC
! 66: /*STUBBORN*/ { &GC_sobjfreelist[0], 0,
! 67: 0 | DS_LENGTH, TRUE /* add length to descr */, TRUE },
! 68: # endif
! 69: };
! 70:
! 71: # ifdef ATOMIC_UNCOLLECTABLE
! 72: # ifdef STUBBORN_ALLOC
! 73: int GC_n_kinds = 5;
! 74: # else
! 75: int GC_n_kinds = 4;
! 76: # endif
! 77: # else
! 78: # ifdef STUBBORN_ALLOC
! 79: int GC_n_kinds = 4;
! 80: # else
! 81: int GC_n_kinds = 3;
! 82: # endif
! 83: # endif
! 84:
! 85:
! 86: # ifndef INITIAL_MARK_STACK_SIZE
! 87: # define INITIAL_MARK_STACK_SIZE (1*HBLKSIZE)
! 88: /* INITIAL_MARK_STACK_SIZE * sizeof(mse) should be a */
! 89: /* multiple of HBLKSIZE. */
! 90: # endif
! 91:
! 92: /*
! 93: * Limits of stack for GC_mark routine.
! 94: * All ranges between GC_mark_stack(incl.) and GC_mark_stack_top(incl.) still
! 95: * need to be marked from.
! 96: */
! 97:
! 98: word GC_n_rescuing_pages; /* Number of dirty pages we marked from */
! 99: /* excludes ptrfree pages, etc. */
! 100:
! 101: mse * GC_mark_stack;
! 102:
! 103: word GC_mark_stack_size = 0;
! 104:
! 105: mse * GC_mark_stack_top;
! 106:
! 107: static struct hblk * scan_ptr;
! 108:
! 109: mark_state_t GC_mark_state = MS_NONE;
! 110:
! 111: GC_bool GC_mark_stack_too_small = FALSE;
! 112:
! 113: GC_bool GC_objects_are_marked = FALSE; /* Are there collectable marked */
! 114: /* objects in the heap? */
! 115:
! 116: /* Is a collection in progress? Note that this can return true in the */
! 117: /* nonincremental case, if a collection has been abandoned and the */
! 118: /* mark state is now MS_INVALID. */
! 119: GC_bool GC_collection_in_progress()
! 120: {
! 121: return(GC_mark_state != MS_NONE);
! 122: }
! 123:
! 124: /* clear all mark bits in the header */
! 125: void GC_clear_hdr_marks(hhdr)
! 126: register hdr * hhdr;
! 127: {
! 128: BZERO(hhdr -> hb_marks, MARK_BITS_SZ*sizeof(word));
! 129: }
! 130:
! 131: /* Set all mark bits in the header. Used for uncollectable blocks. */
! 132: void GC_set_hdr_marks(hhdr)
! 133: register hdr * hhdr;
! 134: {
! 135: register int i;
! 136:
! 137: for (i = 0; i < MARK_BITS_SZ; ++i) {
! 138: hhdr -> hb_marks[i] = ONES;
! 139: }
! 140: }
! 141:
! 142: /*
! 143: * Clear all mark bits associated with block h.
! 144: */
! 145: /*ARGSUSED*/
! 146: static void clear_marks_for_block(h, dummy)
! 147: struct hblk *h;
! 148: word dummy;
! 149: {
! 150: register hdr * hhdr = HDR(h);
! 151:
! 152: if (IS_UNCOLLECTABLE(hhdr -> hb_obj_kind)) return;
! 153: /* Mark bit for these is cleared only once the object is */
! 154: /* explicitly deallocated. This either frees the block, or */
! 155: /* the bit is cleared once the object is on the free list. */
! 156: GC_clear_hdr_marks(hhdr);
! 157: }
! 158:
! 159: /* Slow but general routines for setting/clearing/asking about mark bits */
! 160: void GC_set_mark_bit(p)
! 161: ptr_t p;
! 162: {
! 163: register struct hblk *h = HBLKPTR(p);
! 164: register hdr * hhdr = HDR(h);
! 165: register int word_no = (word *)p - (word *)h;
! 166:
! 167: set_mark_bit_from_hdr(hhdr, word_no);
! 168: }
! 169:
! 170: void GC_clear_mark_bit(p)
! 171: ptr_t p;
! 172: {
! 173: register struct hblk *h = HBLKPTR(p);
! 174: register hdr * hhdr = HDR(h);
! 175: register int word_no = (word *)p - (word *)h;
! 176:
! 177: clear_mark_bit_from_hdr(hhdr, word_no);
! 178: }
! 179:
! 180: GC_bool GC_is_marked(p)
! 181: ptr_t p;
! 182: {
! 183: register struct hblk *h = HBLKPTR(p);
! 184: register hdr * hhdr = HDR(h);
! 185: register int word_no = (word *)p - (word *)h;
! 186:
! 187: return(mark_bit_from_hdr(hhdr, word_no));
! 188: }
! 189:
! 190:
! 191: /*
! 192: * Clear mark bits in all allocated heap blocks. This invalidates
! 193: * the marker invariant, and sets GC_mark_state to reflect this.
! 194: * (This implicitly starts marking to reestablish the invariant.)
! 195: */
! 196: void GC_clear_marks()
! 197: {
! 198: GC_apply_to_all_blocks(clear_marks_for_block, (word)0);
! 199: GC_objects_are_marked = FALSE;
! 200: GC_mark_state = MS_INVALID;
! 201: scan_ptr = 0;
! 202: # ifdef GATHERSTATS
! 203: /* Counters reflect currently marked objects: reset here */
! 204: GC_composite_in_use = 0;
! 205: GC_atomic_in_use = 0;
! 206: # endif
! 207:
! 208: }
! 209:
! 210: /* Initiate a garbage collection. Initiates a full collection if the */
! 211: /* mark state is invalid. */
! 212: /*ARGSUSED*/
! 213: void GC_initiate_gc()
! 214: {
! 215: if (GC_dirty_maintained) GC_read_dirty();
! 216: # ifdef STUBBORN_ALLOC
! 217: GC_read_changed();
! 218: # endif
! 219: # ifdef CHECKSUMS
! 220: {
! 221: extern void GC_check_dirty();
! 222:
! 223: if (GC_dirty_maintained) GC_check_dirty();
! 224: }
! 225: # endif
! 226: # ifdef GATHERSTATS
! 227: GC_n_rescuing_pages = 0;
! 228: # endif
! 229: if (GC_mark_state == MS_NONE) {
! 230: GC_mark_state = MS_PUSH_RESCUERS;
! 231: } else if (GC_mark_state != MS_INVALID) {
! 232: ABORT("unexpected state");
! 233: } /* else this is really a full collection, and mark */
! 234: /* bits are invalid. */
! 235: scan_ptr = 0;
! 236: }
! 237:
! 238:
! 239: static void alloc_mark_stack();
! 240:
! 241: /* Perform a small amount of marking. */
! 242: /* We try to touch roughly a page of memory. */
! 243: /* Return TRUE if we just finished a mark phase. */
! 244: /* Cold_gc_frame is an address inside a GC frame that */
! 245: /* remains valid until all marking is complete. */
! 246: /* A zero value indicates that it's OK to miss some */
! 247: /* register values. */
! 248: GC_bool GC_mark_some(cold_gc_frame)
! 249: ptr_t cold_gc_frame;
! 250: {
! 251: switch(GC_mark_state) {
! 252: case MS_NONE:
! 253: return(FALSE);
! 254:
! 255: case MS_PUSH_RESCUERS:
! 256: if (GC_mark_stack_top
! 257: >= GC_mark_stack + INITIAL_MARK_STACK_SIZE/4) {
! 258: GC_mark_from_mark_stack();
! 259: return(FALSE);
! 260: } else {
! 261: scan_ptr = GC_push_next_marked_dirty(scan_ptr);
! 262: if (scan_ptr == 0) {
! 263: # ifdef PRINTSTATS
! 264: GC_printf1("Marked from %lu dirty pages\n",
! 265: (unsigned long)GC_n_rescuing_pages);
! 266: # endif
! 267: GC_push_roots(FALSE, cold_gc_frame);
! 268: GC_objects_are_marked = TRUE;
! 269: if (GC_mark_state != MS_INVALID) {
! 270: GC_mark_state = MS_ROOTS_PUSHED;
! 271: }
! 272: }
! 273: }
! 274: return(FALSE);
! 275:
! 276: case MS_PUSH_UNCOLLECTABLE:
! 277: if (GC_mark_stack_top
! 278: >= GC_mark_stack + INITIAL_MARK_STACK_SIZE/4) {
! 279: GC_mark_from_mark_stack();
! 280: return(FALSE);
! 281: } else {
! 282: scan_ptr = GC_push_next_marked_uncollectable(scan_ptr);
! 283: if (scan_ptr == 0) {
! 284: GC_push_roots(TRUE, cold_gc_frame);
! 285: GC_objects_are_marked = TRUE;
! 286: if (GC_mark_state != MS_INVALID) {
! 287: GC_mark_state = MS_ROOTS_PUSHED;
! 288: }
! 289: }
! 290: }
! 291: return(FALSE);
! 292:
! 293: case MS_ROOTS_PUSHED:
! 294: if (GC_mark_stack_top >= GC_mark_stack) {
! 295: GC_mark_from_mark_stack();
! 296: return(FALSE);
! 297: } else {
! 298: GC_mark_state = MS_NONE;
! 299: if (GC_mark_stack_too_small) {
! 300: alloc_mark_stack(2*GC_mark_stack_size);
! 301: }
! 302: return(TRUE);
! 303: }
! 304:
! 305: case MS_INVALID:
! 306: case MS_PARTIALLY_INVALID:
! 307: if (!GC_objects_are_marked) {
! 308: GC_mark_state = MS_PUSH_UNCOLLECTABLE;
! 309: return(FALSE);
! 310: }
! 311: if (GC_mark_stack_top >= GC_mark_stack) {
! 312: GC_mark_from_mark_stack();
! 313: return(FALSE);
! 314: }
! 315: if (scan_ptr == 0 && GC_mark_state == MS_INVALID) {
! 316: /* About to start a heap scan for marked objects. */
! 317: /* Mark stack is empty. OK to reallocate. */
! 318: if (GC_mark_stack_too_small) {
! 319: alloc_mark_stack(2*GC_mark_stack_size);
! 320: }
! 321: GC_mark_state = MS_PARTIALLY_INVALID;
! 322: }
! 323: scan_ptr = GC_push_next_marked(scan_ptr);
! 324: if (scan_ptr == 0 && GC_mark_state == MS_PARTIALLY_INVALID) {
! 325: GC_push_roots(TRUE, cold_gc_frame);
! 326: GC_objects_are_marked = TRUE;
! 327: if (GC_mark_state != MS_INVALID) {
! 328: GC_mark_state = MS_ROOTS_PUSHED;
! 329: }
! 330: }
! 331: return(FALSE);
! 332: default:
! 333: ABORT("GC_mark_some: bad state");
! 334: return(FALSE);
! 335: }
! 336: }
! 337:
! 338:
! 339: GC_bool GC_mark_stack_empty()
! 340: {
! 341: return(GC_mark_stack_top < GC_mark_stack);
! 342: }
! 343:
! 344: #ifdef PROF_MARKER
! 345: word GC_prof_array[10];
! 346: # define PROF(n) GC_prof_array[n]++
! 347: #else
! 348: # define PROF(n)
! 349: #endif
! 350:
! 351: /* Given a pointer to someplace other than a small object page or the */
! 352: /* first page of a large object, return a pointer either to the */
! 353: /* start of the large object or NIL. */
! 354: /* In the latter case black list the address current. */
! 355: /* Returns NIL without black listing if current points to a block */
! 356: /* with IGNORE_OFF_PAGE set. */
! 357: /*ARGSUSED*/
! 358: # ifdef PRINT_BLACK_LIST
! 359: word GC_find_start(current, hhdr, source)
! 360: word source;
! 361: # else
! 362: word GC_find_start(current, hhdr)
! 363: # define source 0
! 364: # endif
! 365: register word current;
! 366: register hdr * hhdr;
! 367: {
! 368: # ifdef ALL_INTERIOR_POINTERS
! 369: if (hhdr != 0) {
! 370: register word orig = current;
! 371:
! 372: current = (word)HBLKPTR(current) + HDR_BYTES;
! 373: do {
! 374: current = current - HBLKSIZE*(word)hhdr;
! 375: hhdr = HDR(current);
! 376: } while(IS_FORWARDING_ADDR_OR_NIL(hhdr));
! 377: /* current points to the start of the large object */
! 378: if (hhdr -> hb_flags & IGNORE_OFF_PAGE) return(0);
! 379: if ((word *)orig - (word *)current
! 380: >= (ptrdiff_t)(hhdr->hb_sz)) {
! 381: /* Pointer past the end of the block */
! 382: GC_ADD_TO_BLACK_LIST_NORMAL(orig, source);
! 383: return(0);
! 384: }
! 385: return(current);
! 386: } else {
! 387: GC_ADD_TO_BLACK_LIST_NORMAL(current, source);
! 388: return(0);
! 389: }
! 390: # else
! 391: GC_ADD_TO_BLACK_LIST_NORMAL(current, source);
! 392: return(0);
! 393: # endif
! 394: # undef source
! 395: }
! 396:
! 397: void GC_invalidate_mark_state()
! 398: {
! 399: GC_mark_state = MS_INVALID;
! 400: GC_mark_stack_top = GC_mark_stack-1;
! 401: }
! 402:
! 403: mse * GC_signal_mark_stack_overflow(msp)
! 404: mse * msp;
! 405: {
! 406: GC_mark_state = MS_INVALID;
! 407: GC_mark_stack_too_small = TRUE;
! 408: # ifdef PRINTSTATS
! 409: GC_printf1("Mark stack overflow; current size = %lu entries\n",
! 410: GC_mark_stack_size);
! 411: # endif
! 412: return(msp-INITIAL_MARK_STACK_SIZE/8);
! 413: }
! 414:
! 415:
! 416: /*
! 417: * Mark objects pointed to by the regions described by
! 418: * mark stack entries between GC_mark_stack and GC_mark_stack_top,
! 419: * inclusive. Assumes the upper limit of a mark stack entry
! 420: * is never 0. A mark stack entry never has size 0.
! 421: * We try to traverse on the order of a hblk of memory before we return.
! 422: * Caller is responsible for calling this until the mark stack is empty.
! 423: */
! 424: void GC_mark_from_mark_stack()
! 425: {
! 426: mse * GC_mark_stack_reg = GC_mark_stack;
! 427: mse * GC_mark_stack_top_reg = GC_mark_stack_top;
! 428: mse * mark_stack_limit = &(GC_mark_stack[GC_mark_stack_size]);
! 429: int credit = HBLKSIZE; /* Remaining credit for marking work */
! 430: register word * current_p; /* Pointer to current candidate ptr. */
! 431: register word current; /* Candidate pointer. */
! 432: register word * limit; /* (Incl) limit of current candidate */
! 433: /* range */
! 434: register word descr;
! 435: register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
! 436: register ptr_t least_ha = GC_least_plausible_heap_addr;
! 437: # define SPLIT_RANGE_WORDS 128 /* Must be power of 2. */
! 438:
! 439: GC_objects_are_marked = TRUE;
! 440: # ifdef OS2 /* Use untweaked version to circumvent compiler problem */
! 441: while (GC_mark_stack_top_reg >= GC_mark_stack_reg && credit >= 0) {
! 442: # else
! 443: while ((((ptr_t)GC_mark_stack_top_reg - (ptr_t)GC_mark_stack_reg) | credit)
! 444: >= 0) {
! 445: # endif
! 446: current_p = GC_mark_stack_top_reg -> mse_start;
! 447: retry:
! 448: descr = GC_mark_stack_top_reg -> mse_descr;
! 449: if (descr & ((~(WORDS_TO_BYTES(SPLIT_RANGE_WORDS) - 1)) | DS_TAGS)) {
! 450: word tag = descr & DS_TAGS;
! 451:
! 452: switch(tag) {
! 453: case DS_LENGTH:
! 454: /* Large length. */
! 455: /* Process part of the range to avoid pushing too much on the */
! 456: /* stack. */
! 457: GC_mark_stack_top_reg -> mse_start =
! 458: limit = current_p + SPLIT_RANGE_WORDS-1;
! 459: GC_mark_stack_top_reg -> mse_descr -=
! 460: WORDS_TO_BYTES(SPLIT_RANGE_WORDS-1);
! 461: /* Make sure that pointers overlapping the two ranges are */
! 462: /* considered. */
! 463: limit = (word *)((char *)limit + sizeof(word) - ALIGNMENT);
! 464: break;
! 465: case DS_BITMAP:
! 466: GC_mark_stack_top_reg--;
! 467: descr &= ~DS_TAGS;
! 468: credit -= WORDS_TO_BYTES(WORDSZ/2); /* guess */
! 469: while (descr != 0) {
! 470: if ((signed_word)descr < 0) {
! 471: current = *current_p;
! 472: if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
! 473: PUSH_CONTENTS(current, GC_mark_stack_top_reg, mark_stack_limit,
! 474: current_p, exit1);
! 475: }
! 476: }
! 477: descr <<= 1;
! 478: ++ current_p;
! 479: }
! 480: continue;
! 481: case DS_PROC:
! 482: GC_mark_stack_top_reg--;
! 483: credit -= PROC_BYTES;
! 484: GC_mark_stack_top_reg =
! 485: (*PROC(descr))
! 486: (current_p, GC_mark_stack_top_reg,
! 487: mark_stack_limit, ENV(descr));
! 488: continue;
! 489: case DS_PER_OBJECT:
! 490: GC_mark_stack_top_reg -> mse_descr =
! 491: *(word *)((ptr_t)current_p + descr - tag);
! 492: goto retry;
! 493: }
! 494: } else {
! 495: GC_mark_stack_top_reg--;
! 496: limit = (word *)(((ptr_t)current_p) + (word)descr);
! 497: }
! 498: /* The simple case in which we're scanning a range. */
! 499: credit -= (ptr_t)limit - (ptr_t)current_p;
! 500: limit -= 1;
! 501: while (current_p <= limit) {
! 502: current = *current_p;
! 503: if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
! 504: PUSH_CONTENTS(current, GC_mark_stack_top_reg,
! 505: mark_stack_limit, current_p, exit2);
! 506: }
! 507: current_p = (word *)((char *)current_p + ALIGNMENT);
! 508: }
! 509: }
! 510: GC_mark_stack_top = GC_mark_stack_top_reg;
! 511: }
! 512:
! 513: /* Allocate or reallocate space for mark stack of size s words */
! 514: /* May silently fail. */
! 515: static void alloc_mark_stack(n)
! 516: word n;
! 517: {
! 518: mse * new_stack = (mse *)GC_scratch_alloc(n * sizeof(struct ms_entry));
! 519:
! 520: GC_mark_stack_too_small = FALSE;
! 521: if (GC_mark_stack_size != 0) {
! 522: if (new_stack != 0) {
! 523: word displ = (word)GC_mark_stack & (GC_page_size - 1);
! 524: signed_word size = GC_mark_stack_size * sizeof(struct ms_entry);
! 525:
! 526: /* Recycle old space */
! 527: if (0 != displ) displ = GC_page_size - displ;
! 528: size = (size - displ) & ~(GC_page_size - 1);
! 529: if (size > 0) {
! 530: GC_add_to_heap((struct hblk *)
! 531: ((word)GC_mark_stack + displ), (word)size);
! 532: }
! 533: GC_mark_stack = new_stack;
! 534: GC_mark_stack_size = n;
! 535: # ifdef PRINTSTATS
! 536: GC_printf1("Grew mark stack to %lu frames\n",
! 537: (unsigned long) GC_mark_stack_size);
! 538: # endif
! 539: } else {
! 540: # ifdef PRINTSTATS
! 541: GC_printf1("Failed to grow mark stack to %lu frames\n",
! 542: (unsigned long) n);
! 543: # endif
! 544: }
! 545: } else {
! 546: if (new_stack == 0) {
! 547: GC_err_printf0("No space for mark stack\n");
! 548: EXIT();
! 549: }
! 550: GC_mark_stack = new_stack;
! 551: GC_mark_stack_size = n;
! 552: }
! 553: GC_mark_stack_top = GC_mark_stack-1;
! 554: }
! 555:
! 556: void GC_mark_init()
! 557: {
! 558: alloc_mark_stack(INITIAL_MARK_STACK_SIZE);
! 559: }
! 560:
! 561: /*
! 562: * Push all locations between b and t onto the mark stack.
! 563: * b is the first location to be checked. t is one past the last
! 564: * location to be checked.
! 565: * Should only be used if there is no possibility of mark stack
! 566: * overflow.
! 567: */
! 568: void GC_push_all(bottom, top)
! 569: ptr_t bottom;
! 570: ptr_t top;
! 571: {
! 572: register word length;
! 573:
! 574: bottom = (ptr_t)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
! 575: top = (ptr_t)(((word) top) & ~(ALIGNMENT-1));
! 576: if (top == 0 || bottom == top) return;
! 577: GC_mark_stack_top++;
! 578: if (GC_mark_stack_top >= GC_mark_stack + GC_mark_stack_size) {
! 579: ABORT("unexpected mark stack overflow");
! 580: }
! 581: length = top - bottom;
! 582: # if DS_TAGS > ALIGNMENT - 1
! 583: length += DS_TAGS;
! 584: length &= ~DS_TAGS;
! 585: # endif
! 586: GC_mark_stack_top -> mse_start = (word *)bottom;
! 587: GC_mark_stack_top -> mse_descr = length;
! 588: }
! 589:
! 590: /*
! 591: * Analogous to the above, but push only those pages that may have been
! 592: * dirtied. A block h is assumed dirty if dirty_fn(h) != 0.
! 593: * We use push_fn to actually push the block.
! 594: * Will not overflow mark stack if push_fn pushes a small fixed number
! 595: * of entries. (This is invoked only if push_fn pushes a single entry,
! 596: * or if it marks each object before pushing it, thus ensuring progress
! 597: * in the event of a stack overflow.)
! 598: */
! 599: void GC_push_dirty(bottom, top, dirty_fn, push_fn)
! 600: ptr_t bottom;
! 601: ptr_t top;
! 602: int (*dirty_fn)(/* struct hblk * h */);
! 603: void (*push_fn)(/* ptr_t bottom, ptr_t top */);
! 604: {
! 605: register struct hblk * h;
! 606:
! 607: bottom = (ptr_t)(((long) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
! 608: top = (ptr_t)(((long) top) & ~(ALIGNMENT-1));
! 609:
! 610: if (top == 0 || bottom == top) return;
! 611: h = HBLKPTR(bottom + HBLKSIZE);
! 612: if (top <= (ptr_t) h) {
! 613: if ((*dirty_fn)(h-1)) {
! 614: (*push_fn)(bottom, top);
! 615: }
! 616: return;
! 617: }
! 618: if ((*dirty_fn)(h-1)) {
! 619: (*push_fn)(bottom, (ptr_t)h);
! 620: }
! 621: while ((ptr_t)(h+1) <= top) {
! 622: if ((*dirty_fn)(h)) {
! 623: if ((word)(GC_mark_stack_top - GC_mark_stack)
! 624: > 3 * GC_mark_stack_size / 4) {
! 625: /* Danger of mark stack overflow */
! 626: (*push_fn)((ptr_t)h, top);
! 627: return;
! 628: } else {
! 629: (*push_fn)((ptr_t)h, (ptr_t)(h+1));
! 630: }
! 631: }
! 632: h++;
! 633: }
! 634: if ((ptr_t)h != top) {
! 635: if ((*dirty_fn)(h)) {
! 636: (*push_fn)((ptr_t)h, top);
! 637: }
! 638: }
! 639: if (GC_mark_stack_top >= GC_mark_stack + GC_mark_stack_size) {
! 640: ABORT("unexpected mark stack overflow");
! 641: }
! 642: }
! 643:
! 644: # ifndef SMALL_CONFIG
! 645: void GC_push_conditional(bottom, top, all)
! 646: ptr_t bottom;
! 647: ptr_t top;
! 648: int all;
! 649: {
! 650: if (all) {
! 651: if (GC_dirty_maintained) {
! 652: # ifdef PROC_VDB
! 653: /* Pages that were never dirtied cannot contain pointers */
! 654: GC_push_dirty(bottom, top, GC_page_was_ever_dirty, GC_push_all);
! 655: # else
! 656: GC_push_all(bottom, top);
! 657: # endif
! 658: } else {
! 659: GC_push_all(bottom, top);
! 660: }
! 661: } else {
! 662: GC_push_dirty(bottom, top, GC_page_was_dirty, GC_push_all);
! 663: }
! 664: }
! 665: #endif
! 666:
! 667: # ifdef MSWIN32
! 668: void __cdecl GC_push_one(p)
! 669: # else
! 670: void GC_push_one(p)
! 671: # endif
! 672: word p;
! 673: {
! 674: GC_PUSH_ONE_STACK(p, 0);
! 675: }
! 676:
! 677: # ifdef __STDC__
! 678: # define BASE(p) (word)GC_base((void *)(p))
! 679: # else
! 680: # define BASE(p) (word)GC_base((char *)(p))
! 681: # endif
! 682:
! 683: /* As above, but argument passed preliminary test. */
! 684: # ifdef PRINT_BLACK_LIST
! 685: void GC_push_one_checked(p, interior_ptrs, source)
! 686: ptr_t source;
! 687: # else
! 688: void GC_push_one_checked(p, interior_ptrs)
! 689: # define source 0
! 690: # endif
! 691: register word p;
! 692: register GC_bool interior_ptrs;
! 693: {
! 694: register word r;
! 695: register hdr * hhdr;
! 696: register int displ;
! 697:
! 698: GET_HDR(p, hhdr);
! 699: if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
! 700: if (hhdr != 0 && interior_ptrs) {
! 701: r = BASE(p);
! 702: hhdr = HDR(r);
! 703: displ = BYTES_TO_WORDS(HBLKDISPL(r));
! 704: } else {
! 705: hhdr = 0;
! 706: }
! 707: } else {
! 708: register map_entry_type map_entry;
! 709:
! 710: displ = HBLKDISPL(p);
! 711: map_entry = MAP_ENTRY((hhdr -> hb_map), displ);
! 712: if (map_entry == OBJ_INVALID) {
! 713: # ifndef ALL_INTERIOR_POINTERS
! 714: if (interior_ptrs) {
! 715: r = BASE(p);
! 716: displ = BYTES_TO_WORDS(HBLKDISPL(r));
! 717: if (r == 0) hhdr = 0;
! 718: } else {
! 719: hhdr = 0;
! 720: }
! 721: # else
! 722: /* map already reflects interior pointers */
! 723: hhdr = 0;
! 724: # endif
! 725: } else {
! 726: displ = BYTES_TO_WORDS(displ);
! 727: displ -= map_entry;
! 728: r = (word)((word *)(HBLKPTR(p)) + displ);
! 729: }
! 730: }
! 731: /* If hhdr != 0 then r == GC_base(p), only we did it faster. */
! 732: /* displ is the word index within the block. */
! 733: if (hhdr == 0) {
! 734: if (interior_ptrs) {
! 735: # ifdef PRINT_BLACK_LIST
! 736: GC_add_to_black_list_stack(p, source);
! 737: # else
! 738: GC_add_to_black_list_stack(p);
! 739: # endif
! 740: } else {
! 741: GC_ADD_TO_BLACK_LIST_NORMAL(p, source);
! 742: # undef source /* In case we had to define it. */
! 743: }
! 744: } else {
! 745: if (!mark_bit_from_hdr(hhdr, displ)) {
! 746: set_mark_bit_from_hdr(hhdr, displ);
! 747: PUSH_OBJ((word *)r, hhdr, GC_mark_stack_top,
! 748: &(GC_mark_stack[GC_mark_stack_size]));
! 749: }
! 750: }
! 751: }
! 752:
! 753: # ifdef TRACE_BUF
! 754:
! 755: # define TRACE_ENTRIES 1000
! 756:
! 757: struct trace_entry {
! 758: char * kind;
! 759: word gc_no;
! 760: word words_allocd;
! 761: word arg1;
! 762: word arg2;
! 763: } GC_trace_buf[TRACE_ENTRIES];
! 764:
! 765: int GC_trace_buf_ptr = 0;
! 766:
! 767: void GC_add_trace_entry(char *kind, word arg1, word arg2)
! 768: {
! 769: GC_trace_buf[GC_trace_buf_ptr].kind = kind;
! 770: GC_trace_buf[GC_trace_buf_ptr].gc_no = GC_gc_no;
! 771: GC_trace_buf[GC_trace_buf_ptr].words_allocd = GC_words_allocd;
! 772: GC_trace_buf[GC_trace_buf_ptr].arg1 = arg1 ^ 0x80000000;
! 773: GC_trace_buf[GC_trace_buf_ptr].arg2 = arg2 ^ 0x80000000;
! 774: GC_trace_buf_ptr++;
! 775: if (GC_trace_buf_ptr >= TRACE_ENTRIES) GC_trace_buf_ptr = 0;
! 776: }
! 777:
! 778: void GC_print_trace(word gc_no, GC_bool lock)
! 779: {
! 780: int i;
! 781: struct trace_entry *p;
! 782:
! 783: if (lock) LOCK();
! 784: for (i = GC_trace_buf_ptr-1; i != GC_trace_buf_ptr; i--) {
! 785: if (i < 0) i = TRACE_ENTRIES-1;
! 786: p = GC_trace_buf + i;
! 787: if (p -> gc_no < gc_no || p -> kind == 0) return;
! 788: printf("Trace:%s (gc:%d,words:%d) 0x%X, 0x%X\n",
! 789: p -> kind, p -> gc_no, p -> words_allocd,
! 790: (p -> arg1) ^ 0x80000000, (p -> arg2) ^ 0x80000000);
! 791: }
! 792: printf("Trace incomplete\n");
! 793: if (lock) UNLOCK();
! 794: }
! 795:
! 796: # endif /* TRACE_BUF */
! 797:
! 798: /*
! 799: * A version of GC_push_all that treats all interior pointers as valid
! 800: * and scans the entire region immediately, in case the contents
! 801: * change.
! 802: */
! 803: void GC_push_all_eager(bottom, top)
! 804: ptr_t bottom;
! 805: ptr_t top;
! 806: {
! 807: word * b = (word *)(((long) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
! 808: word * t = (word *)(((long) top) & ~(ALIGNMENT-1));
! 809: register word *p;
! 810: register word q;
! 811: register word *lim;
! 812: register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
! 813: register ptr_t least_ha = GC_least_plausible_heap_addr;
! 814: # define GC_greatest_plausible_heap_addr greatest_ha
! 815: # define GC_least_plausible_heap_addr least_ha
! 816:
! 817: if (top == 0) return;
! 818: /* check all pointers in range and put in push if they appear */
! 819: /* to be valid. */
! 820: lim = t - 1 /* longword */;
! 821: for (p = b; p <= lim; p = (word *)(((char *)p) + ALIGNMENT)) {
! 822: q = *p;
! 823: GC_PUSH_ONE_STACK(q, p);
! 824: }
! 825: # undef GC_greatest_plausible_heap_addr
! 826: # undef GC_least_plausible_heap_addr
! 827: }
! 828:
! 829: #ifndef THREADS
! 830: /*
! 831: * A version of GC_push_all that treats all interior pointers as valid
! 832: * and scans part of the area immediately, to make sure that saved
! 833: * register values are not lost.
! 834: * Cold_gc_frame delimits the stack section that must be scanned
! 835: * eagerly. A zero value indicates that no eager scanning is needed.
! 836: */
! 837: void GC_push_all_stack_partially_eager(bottom, top, cold_gc_frame)
! 838: ptr_t bottom;
! 839: ptr_t top;
! 840: ptr_t cold_gc_frame;
! 841: {
! 842: # ifdef ALL_INTERIOR_POINTERS
! 843: # define EAGER_BYTES 1024
! 844: /* Push the hot end of the stack eagerly, so that register values */
! 845: /* saved inside GC frames are marked before they disappear. */
! 846: /* The rest of the marking can be deferred until later. */
! 847: if (0 == cold_gc_frame) {
! 848: GC_push_all_stack(bottom, top);
! 849: return;
! 850: }
! 851: # ifdef STACK_GROWS_DOWN
! 852: GC_push_all_eager(bottom, cold_gc_frame);
! 853: GC_push_all(cold_gc_frame - sizeof(ptr_t), top);
! 854: # else /* STACK_GROWS_UP */
! 855: GC_push_all_eager(cold_gc_frame, top);
! 856: GC_push_all(bottom, cold_gc_frame + sizeof(ptr_t));
! 857: # endif /* STACK_GROWS_UP */
! 858: # else
! 859: GC_push_all_eager(bottom, top);
! 860: # endif
! 861: # ifdef TRACE_BUF
! 862: GC_add_trace_entry("GC_push_all_stack", bottom, top);
! 863: # endif
! 864: }
! 865: #endif /* !THREADS */
! 866:
! 867: void GC_push_all_stack(bottom, top)
! 868: ptr_t bottom;
! 869: ptr_t top;
! 870: {
! 871: # ifdef ALL_INTERIOR_POINTERS
! 872: GC_push_all(bottom, top);
! 873: # else
! 874: GC_push_all_eager(bottom, top);
! 875: # endif
! 876: }
! 877:
! 878: #ifndef SMALL_CONFIG
! 879: /* Push all objects reachable from marked objects in the given block */
! 880: /* of size 1 objects. */
! 881: void GC_push_marked1(h, hhdr)
! 882: struct hblk *h;
! 883: register hdr * hhdr;
! 884: {
! 885: word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
! 886: register word *p;
! 887: word *plim;
! 888: register int i;
! 889: register word q;
! 890: register word mark_word;
! 891: register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
! 892: register ptr_t least_ha = GC_least_plausible_heap_addr;
! 893: # define GC_greatest_plausible_heap_addr greatest_ha
! 894: # define GC_least_plausible_heap_addr least_ha
! 895:
! 896: p = (word *)(h->hb_body);
! 897: plim = (word *)(((word)h) + HBLKSIZE);
! 898:
! 899: /* go through all words in block */
! 900: while( p < plim ) {
! 901: mark_word = *mark_word_addr++;
! 902: i = 0;
! 903: while(mark_word != 0) {
! 904: if (mark_word & 1) {
! 905: q = p[i];
! 906: GC_PUSH_ONE_HEAP(q, p + i);
! 907: }
! 908: i++;
! 909: mark_word >>= 1;
! 910: }
! 911: p += WORDSZ;
! 912: }
! 913: # undef GC_greatest_plausible_heap_addr
! 914: # undef GC_least_plausible_heap_addr
! 915: }
! 916:
! 917:
! 918: #ifndef UNALIGNED
! 919:
! 920: /* Push all objects reachable from marked objects in the given block */
! 921: /* of size 2 objects. */
! 922: void GC_push_marked2(h, hhdr)
! 923: struct hblk *h;
! 924: register hdr * hhdr;
! 925: {
! 926: word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
! 927: register word *p;
! 928: word *plim;
! 929: register int i;
! 930: register word q;
! 931: register word mark_word;
! 932: register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
! 933: register ptr_t least_ha = GC_least_plausible_heap_addr;
! 934: # define GC_greatest_plausible_heap_addr greatest_ha
! 935: # define GC_least_plausible_heap_addr least_ha
! 936:
! 937: p = (word *)(h->hb_body);
! 938: plim = (word *)(((word)h) + HBLKSIZE);
! 939:
! 940: /* go through all words in block */
! 941: while( p < plim ) {
! 942: mark_word = *mark_word_addr++;
! 943: i = 0;
! 944: while(mark_word != 0) {
! 945: if (mark_word & 1) {
! 946: q = p[i];
! 947: GC_PUSH_ONE_HEAP(q, p + i);
! 948: q = p[i+1];
! 949: GC_PUSH_ONE_HEAP(q, p + i);
! 950: }
! 951: i += 2;
! 952: mark_word >>= 2;
! 953: }
! 954: p += WORDSZ;
! 955: }
! 956: # undef GC_greatest_plausible_heap_addr
! 957: # undef GC_least_plausible_heap_addr
! 958: }
! 959:
! 960: /* Push all objects reachable from marked objects in the given block */
! 961: /* of size 4 objects. */
! 962: /* There is a risk of mark stack overflow here. But we handle that. */
! 963: /* And only unmarked objects get pushed, so it's not very likely. */
! 964: void GC_push_marked4(h, hhdr)
! 965: struct hblk *h;
! 966: register hdr * hhdr;
! 967: {
! 968: word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
! 969: register word *p;
! 970: word *plim;
! 971: register int i;
! 972: register word q;
! 973: register word mark_word;
! 974: register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
! 975: register ptr_t least_ha = GC_least_plausible_heap_addr;
! 976: # define GC_greatest_plausible_heap_addr greatest_ha
! 977: # define GC_least_plausible_heap_addr least_ha
! 978:
! 979: p = (word *)(h->hb_body);
! 980: plim = (word *)(((word)h) + HBLKSIZE);
! 981:
! 982: /* go through all words in block */
! 983: while( p < plim ) {
! 984: mark_word = *mark_word_addr++;
! 985: i = 0;
! 986: while(mark_word != 0) {
! 987: if (mark_word & 1) {
! 988: q = p[i];
! 989: GC_PUSH_ONE_HEAP(q, p + i);
! 990: q = p[i+1];
! 991: GC_PUSH_ONE_HEAP(q, p + i + 1);
! 992: q = p[i+2];
! 993: GC_PUSH_ONE_HEAP(q, p + i + 2);
! 994: q = p[i+3];
! 995: GC_PUSH_ONE_HEAP(q, p + i + 3);
! 996: }
! 997: i += 4;
! 998: mark_word >>= 4;
! 999: }
! 1000: p += WORDSZ;
! 1001: }
! 1002: # undef GC_greatest_plausible_heap_addr
! 1003: # undef GC_least_plausible_heap_addr
! 1004: }
! 1005:
! 1006: #endif /* UNALIGNED */
! 1007:
! 1008: #endif /* SMALL_CONFIG */
! 1009:
! 1010: /* Push all objects reachable from marked objects in the given block */
! 1011: void GC_push_marked(h, hhdr)
! 1012: struct hblk *h;
! 1013: register hdr * hhdr;
! 1014: {
! 1015: register int sz = hhdr -> hb_sz;
! 1016: register word * p;
! 1017: register int word_no;
! 1018: register word * lim;
! 1019: register mse * GC_mark_stack_top_reg;
! 1020: register mse * mark_stack_limit = &(GC_mark_stack[GC_mark_stack_size]);
! 1021:
! 1022: /* Some quick shortcuts: */
! 1023: {
! 1024: struct obj_kind *ok = &(GC_obj_kinds[hhdr -> hb_obj_kind]);
! 1025: if ((0 | DS_LENGTH) == ok -> ok_descriptor
! 1026: && FALSE == ok -> ok_relocate_descr)
! 1027: return;
! 1028: }
! 1029: if (GC_block_empty(hhdr)/* nothing marked */) return;
! 1030: # ifdef GATHERSTATS
! 1031: GC_n_rescuing_pages++;
! 1032: # endif
! 1033: GC_objects_are_marked = TRUE;
! 1034: if (sz > MAXOBJSZ) {
! 1035: lim = (word *)(h + 1);
! 1036: } else {
! 1037: lim = (word *)(h + 1) - sz;
! 1038: }
! 1039:
! 1040: switch(sz) {
! 1041: # if !defined(SMALL_CONFIG)
! 1042: case 1:
! 1043: GC_push_marked1(h, hhdr);
! 1044: break;
! 1045: # endif
! 1046: # if !defined(SMALL_CONFIG) && !defined(UNALIGNED)
! 1047: case 2:
! 1048: GC_push_marked2(h, hhdr);
! 1049: break;
! 1050: case 4:
! 1051: GC_push_marked4(h, hhdr);
! 1052: break;
! 1053: # endif
! 1054: default:
! 1055: GC_mark_stack_top_reg = GC_mark_stack_top;
! 1056: for (p = (word *)h + HDR_WORDS, word_no = HDR_WORDS; p <= lim;
! 1057: p += sz, word_no += sz) {
! 1058: /* This ignores user specified mark procs. This currently */
! 1059: /* doesn't matter, since marking from the whole object */
! 1060: /* is always sufficient, and we will eventually use the user */
! 1061: /* mark proc to avoid any bogus pointers. */
! 1062: if (mark_bit_from_hdr(hhdr, word_no)) {
! 1063: /* Mark from fields inside the object */
! 1064: PUSH_OBJ((word *)p, hhdr, GC_mark_stack_top_reg, mark_stack_limit);
! 1065: # ifdef GATHERSTATS
! 1066: /* Subtract this object from total, since it was */
! 1067: /* added in twice. */
! 1068: GC_composite_in_use -= sz;
! 1069: # endif
! 1070: }
! 1071: }
! 1072: GC_mark_stack_top = GC_mark_stack_top_reg;
! 1073: }
! 1074: }
! 1075:
! 1076: #ifndef SMALL_CONFIG
! 1077: /* Test whether any page in the given block is dirty */
! 1078: GC_bool GC_block_was_dirty(h, hhdr)
! 1079: struct hblk *h;
! 1080: register hdr * hhdr;
! 1081: {
! 1082: register int sz = hhdr -> hb_sz;
! 1083:
! 1084: if (sz < MAXOBJSZ) {
! 1085: return(GC_page_was_dirty(h));
! 1086: } else {
! 1087: register ptr_t p = (ptr_t)h;
! 1088: sz += HDR_WORDS;
! 1089: sz = WORDS_TO_BYTES(sz);
! 1090: while (p < (ptr_t)h + sz) {
! 1091: if (GC_page_was_dirty((struct hblk *)p)) return(TRUE);
! 1092: p += HBLKSIZE;
! 1093: }
! 1094: return(FALSE);
! 1095: }
! 1096: }
! 1097: #endif /* SMALL_CONFIG */
! 1098:
! 1099: /* Similar to GC_push_next_marked, but return address of next block */
! 1100: struct hblk * GC_push_next_marked(h)
! 1101: struct hblk *h;
! 1102: {
! 1103: register hdr * hhdr;
! 1104:
! 1105: h = GC_next_block(h);
! 1106: if (h == 0) return(0);
! 1107: hhdr = HDR(h);
! 1108: GC_push_marked(h, hhdr);
! 1109: return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
! 1110: }
! 1111:
! 1112: #ifndef SMALL_CONFIG
! 1113: /* Identical to above, but mark only from dirty pages */
! 1114: struct hblk * GC_push_next_marked_dirty(h)
! 1115: struct hblk *h;
! 1116: {
! 1117: register hdr * hhdr = HDR(h);
! 1118:
! 1119: if (!GC_dirty_maintained) { ABORT("dirty bits not set up"); }
! 1120: for (;;) {
! 1121: h = GC_next_block(h);
! 1122: if (h == 0) return(0);
! 1123: hhdr = HDR(h);
! 1124: # ifdef STUBBORN_ALLOC
! 1125: if (hhdr -> hb_obj_kind == STUBBORN) {
! 1126: if (GC_page_was_changed(h) && GC_block_was_dirty(h, hhdr)) {
! 1127: break;
! 1128: }
! 1129: } else {
! 1130: if (GC_block_was_dirty(h, hhdr)) break;
! 1131: }
! 1132: # else
! 1133: if (GC_block_was_dirty(h, hhdr)) break;
! 1134: # endif
! 1135: h += OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
! 1136: }
! 1137: GC_push_marked(h, hhdr);
! 1138: return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
! 1139: }
! 1140: #endif
! 1141:
! 1142: /* Similar to above, but for uncollectable pages. Needed since we */
! 1143: /* do not clear marks for such pages, even for full collections. */
! 1144: struct hblk * GC_push_next_marked_uncollectable(h)
! 1145: struct hblk *h;
! 1146: {
! 1147: register hdr * hhdr = HDR(h);
! 1148:
! 1149: for (;;) {
! 1150: h = GC_next_block(h);
! 1151: if (h == 0) return(0);
! 1152: hhdr = HDR(h);
! 1153: if (hhdr -> hb_obj_kind == UNCOLLECTABLE) break;
! 1154: h += OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
! 1155: }
! 1156: GC_push_marked(h, hhdr);
! 1157: return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
! 1158: }
! 1159:
! 1160:
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