Annotation of OpenXM_contrib2/asir2000/gc/headers.c, Revision 1.1
1.1 ! noro 1: /*
! 2: * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
! 3: * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
! 4: * Copyright (c) 1996 by Silicon Graphics. 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: * This implements:
! 18: * 1. allocation of heap block headers
! 19: * 2. A map from addresses to heap block addresses to heap block headers
! 20: *
! 21: * Access speed is crucial. We implement an index structure based on a 2
! 22: * level tree.
! 23: */
! 24:
! 25: # include "gc_priv.h"
! 26:
! 27: bottom_index * GC_all_bottom_indices = 0;
! 28: /* Pointer to first (lowest addr) */
! 29: /* bottom_index. */
! 30:
! 31: bottom_index * GC_all_bottom_indices_end = 0;
! 32: /* Pointer to last (highest addr) */
! 33: /* bottom_index. */
! 34:
! 35: /* Non-macro version of header location routine */
! 36: hdr * GC_find_header(h)
! 37: ptr_t h;
! 38: {
! 39: # ifdef HASH_TL
! 40: register hdr * result;
! 41: GET_HDR(h, result);
! 42: return(result);
! 43: # else
! 44: return(HDR_INNER(h));
! 45: # endif
! 46: }
! 47:
! 48: /* Routines to dynamically allocate collector data structures that will */
! 49: /* never be freed. */
! 50:
! 51: static ptr_t scratch_free_ptr = 0;
! 52:
! 53: ptr_t GC_scratch_end_ptr = 0;
! 54:
! 55: ptr_t GC_scratch_last_end_ptr = 0;
! 56: /* End point of last obtained scratch area */
! 57:
! 58: ptr_t GC_scratch_alloc(bytes)
! 59: register word bytes;
! 60: {
! 61: register ptr_t result = scratch_free_ptr;
! 62:
! 63: # ifdef ALIGN_DOUBLE
! 64: # define GRANULARITY (2 * sizeof(word))
! 65: # else
! 66: # define GRANULARITY sizeof(word)
! 67: # endif
! 68: bytes += GRANULARITY-1;
! 69: bytes &= ~(GRANULARITY-1);
! 70: scratch_free_ptr += bytes;
! 71: if (scratch_free_ptr <= GC_scratch_end_ptr) {
! 72: return(result);
! 73: }
! 74: {
! 75: word bytes_to_get = MINHINCR * HBLKSIZE;
! 76:
! 77: if (bytes_to_get <= bytes) {
! 78: /* Undo the damage, and get memory directly */
! 79: bytes_to_get = bytes;
! 80: # ifdef USE_MMAP
! 81: bytes_to_get += GC_page_size - 1;
! 82: bytes_to_get &= ~(GC_page_size - 1);
! 83: # endif
! 84: result = (ptr_t)GET_MEM(bytes_to_get);
! 85: scratch_free_ptr -= bytes;
! 86: GC_scratch_last_end_ptr = result + bytes;
! 87: return(result);
! 88: }
! 89: result = (ptr_t)GET_MEM(bytes_to_get);
! 90: if (result == 0) {
! 91: # ifdef PRINTSTATS
! 92: GC_printf0("Out of memory - trying to allocate less\n");
! 93: # endif
! 94: scratch_free_ptr -= bytes;
! 95: bytes_to_get = bytes;
! 96: # ifdef USE_MMAP
! 97: bytes_to_get += GC_page_size - 1;
! 98: bytes_to_get &= ~(GC_page_size - 1);
! 99: # endif
! 100: return((ptr_t)GET_MEM(bytes_to_get));
! 101: }
! 102: scratch_free_ptr = result;
! 103: GC_scratch_end_ptr = scratch_free_ptr + bytes_to_get;
! 104: GC_scratch_last_end_ptr = GC_scratch_end_ptr;
! 105: return(GC_scratch_alloc(bytes));
! 106: }
! 107: }
! 108:
! 109: static hdr * hdr_free_list = 0;
! 110:
! 111: /* Return an uninitialized header */
! 112: static hdr * alloc_hdr()
! 113: {
! 114: register hdr * result;
! 115:
! 116: if (hdr_free_list == 0) {
! 117: result = (hdr *) GC_scratch_alloc((word)(sizeof(hdr)));
! 118: } else {
! 119: result = hdr_free_list;
! 120: hdr_free_list = (hdr *) (result -> hb_next);
! 121: }
! 122: return(result);
! 123: }
! 124:
! 125: static void free_hdr(hhdr)
! 126: hdr * hhdr;
! 127: {
! 128: hhdr -> hb_next = (struct hblk *) hdr_free_list;
! 129: hdr_free_list = hhdr;
! 130: }
! 131:
! 132: void GC_init_headers()
! 133: {
! 134: register unsigned i;
! 135:
! 136: GC_all_nils = (bottom_index *)GC_scratch_alloc((word)sizeof(bottom_index));
! 137: BZERO(GC_all_nils, sizeof(bottom_index));
! 138: for (i = 0; i < TOP_SZ; i++) {
! 139: GC_top_index[i] = GC_all_nils;
! 140: }
! 141: }
! 142:
! 143: /* Make sure that there is a bottom level index block for address addr */
! 144: /* Return FALSE on failure. */
! 145: static GC_bool get_index(addr)
! 146: word addr;
! 147: {
! 148: word hi = (word)(addr) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE);
! 149: bottom_index * r;
! 150: bottom_index * p;
! 151: bottom_index ** prev;
! 152: bottom_index *pi;
! 153:
! 154: # ifdef HASH_TL
! 155: unsigned i = TL_HASH(hi);
! 156: bottom_index * old;
! 157:
! 158: old = p = GC_top_index[i];
! 159: while(p != GC_all_nils) {
! 160: if (p -> key == hi) return(TRUE);
! 161: p = p -> hash_link;
! 162: }
! 163: r = (bottom_index*)GC_scratch_alloc((word)(sizeof (bottom_index)));
! 164: if (r == 0) return(FALSE);
! 165: BZERO(r, sizeof (bottom_index));
! 166: r -> hash_link = old;
! 167: GC_top_index[i] = r;
! 168: # else
! 169: if (GC_top_index[hi] != GC_all_nils) return(TRUE);
! 170: r = (bottom_index*)GC_scratch_alloc((word)(sizeof (bottom_index)));
! 171: if (r == 0) return(FALSE);
! 172: GC_top_index[hi] = r;
! 173: BZERO(r, sizeof (bottom_index));
! 174: # endif
! 175: r -> key = hi;
! 176: /* Add it to the list of bottom indices */
! 177: prev = &GC_all_bottom_indices; /* pointer to p */
! 178: pi = 0; /* bottom_index preceding p */
! 179: while ((p = *prev) != 0 && p -> key < hi) {
! 180: pi = p;
! 181: prev = &(p -> asc_link);
! 182: }
! 183: r -> desc_link = pi;
! 184: if (0 == p) {
! 185: GC_all_bottom_indices_end = r;
! 186: } else {
! 187: p -> desc_link = r;
! 188: }
! 189: r -> asc_link = p;
! 190: *prev = r;
! 191: return(TRUE);
! 192: }
! 193:
! 194: /* Install a header for block h. */
! 195: /* The header is uninitialized. */
! 196: /* Returns FALSE on failure. */
! 197: GC_bool GC_install_header(h)
! 198: register struct hblk * h;
! 199: {
! 200: hdr * result;
! 201:
! 202: if (!get_index((word) h)) return(FALSE);
! 203: result = alloc_hdr();
! 204: SET_HDR(h, result);
! 205: # ifdef USE_MUNMAP
! 206: result -> hb_last_reclaimed = GC_gc_no;
! 207: # endif
! 208: return(result != 0);
! 209: }
! 210:
! 211: /* Set up forwarding counts for block h of size sz */
! 212: GC_bool GC_install_counts(h, sz)
! 213: register struct hblk * h;
! 214: register word sz; /* bytes */
! 215: {
! 216: register struct hblk * hbp;
! 217: register int i;
! 218:
! 219: for (hbp = h; (char *)hbp < (char *)h + sz; hbp += BOTTOM_SZ) {
! 220: if (!get_index((word) hbp)) return(FALSE);
! 221: }
! 222: if (!get_index((word)h + sz - 1)) return(FALSE);
! 223: for (hbp = h + 1; (char *)hbp < (char *)h + sz; hbp += 1) {
! 224: i = HBLK_PTR_DIFF(hbp, h);
! 225: SET_HDR(hbp, (hdr *)(i > MAX_JUMP? MAX_JUMP : i));
! 226: }
! 227: return(TRUE);
! 228: }
! 229:
! 230: /* Remove the header for block h */
! 231: void GC_remove_header(h)
! 232: register struct hblk * h;
! 233: {
! 234: hdr ** ha;
! 235:
! 236: GET_HDR_ADDR(h, ha);
! 237: free_hdr(*ha);
! 238: *ha = 0;
! 239: }
! 240:
! 241: /* Remove forwarding counts for h */
! 242: void GC_remove_counts(h, sz)
! 243: register struct hblk * h;
! 244: register word sz; /* bytes */
! 245: {
! 246: register struct hblk * hbp;
! 247:
! 248: for (hbp = h+1; (char *)hbp < (char *)h + sz; hbp += 1) {
! 249: SET_HDR(hbp, 0);
! 250: }
! 251: }
! 252:
! 253: /* Apply fn to all allocated blocks */
! 254: /*VARARGS1*/
! 255: void GC_apply_to_all_blocks(fn, client_data)
! 256: void (*fn)(/* struct hblk *h, word client_data */);
! 257: word client_data;
! 258: {
! 259: register int j;
! 260: register bottom_index * index_p;
! 261:
! 262: for (index_p = GC_all_bottom_indices; index_p != 0;
! 263: index_p = index_p -> asc_link) {
! 264: for (j = BOTTOM_SZ-1; j >= 0;) {
! 265: if (!IS_FORWARDING_ADDR_OR_NIL(index_p->index[j])) {
! 266: if (index_p->index[j]->hb_map != GC_invalid_map) {
! 267: (*fn)(((struct hblk *)
! 268: (((index_p->key << LOG_BOTTOM_SZ) + (word)j)
! 269: << LOG_HBLKSIZE)),
! 270: client_data);
! 271: }
! 272: j--;
! 273: } else if (index_p->index[j] == 0) {
! 274: j--;
! 275: } else {
! 276: j -= (word)(index_p->index[j]);
! 277: }
! 278: }
! 279: }
! 280: }
! 281:
! 282: /* Get the next valid block whose address is at least h */
! 283: /* Return 0 if there is none. */
! 284: struct hblk * GC_next_used_block(h)
! 285: struct hblk * h;
! 286: {
! 287: register bottom_index * bi;
! 288: register word j = ((word)h >> LOG_HBLKSIZE) & (BOTTOM_SZ-1);
! 289:
! 290: GET_BI(h, bi);
! 291: if (bi == GC_all_nils) {
! 292: register word hi = (word)h >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE);
! 293: bi = GC_all_bottom_indices;
! 294: while (bi != 0 && bi -> key < hi) bi = bi -> asc_link;
! 295: j = 0;
! 296: }
! 297: while(bi != 0) {
! 298: while (j < BOTTOM_SZ) {
! 299: hdr * hhdr = bi -> index[j];
! 300: if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
! 301: j++;
! 302: } else {
! 303: if (hhdr->hb_map != GC_invalid_map) {
! 304: return((struct hblk *)
! 305: (((bi -> key << LOG_BOTTOM_SZ) + j)
! 306: << LOG_HBLKSIZE));
! 307: } else {
! 308: j += divHBLKSZ(hhdr -> hb_sz);
! 309: }
! 310: }
! 311: }
! 312: j = 0;
! 313: bi = bi -> asc_link;
! 314: }
! 315: return(0);
! 316: }
! 317:
! 318: /* Get the last (highest address) block whose address is */
! 319: /* at most h. Return 0 if there is none. */
! 320: /* Unlike the above, this may return a free block. */
! 321: struct hblk * GC_prev_block(h)
! 322: struct hblk * h;
! 323: {
! 324: register bottom_index * bi;
! 325: register signed_word j = ((word)h >> LOG_HBLKSIZE) & (BOTTOM_SZ-1);
! 326:
! 327: GET_BI(h, bi);
! 328: if (bi == GC_all_nils) {
! 329: register word hi = (word)h >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE);
! 330: bi = GC_all_bottom_indices_end;
! 331: while (bi != 0 && bi -> key > hi) bi = bi -> desc_link;
! 332: j = BOTTOM_SZ - 1;
! 333: }
! 334: while(bi != 0) {
! 335: while (j >= 0) {
! 336: hdr * hhdr = bi -> index[j];
! 337: if (0 == hhdr) {
! 338: --j;
! 339: } else if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
! 340: j -= (signed_word)hhdr;
! 341: } else {
! 342: return((struct hblk *)
! 343: (((bi -> key << LOG_BOTTOM_SZ) + j)
! 344: << LOG_HBLKSIZE));
! 345: }
! 346: }
! 347: j = BOTTOM_SZ - 1;
! 348: bi = bi -> desc_link;
! 349: }
! 350: return(0);
! 351: }
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