Annotation of OpenXM_contrib/gc/headers.c, Revision 1.1
1.1 ! maekawa 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:
! 29: /* Non-macro version of header location routine */
! 30: hdr * GC_find_header(h)
! 31: ptr_t h;
! 32: {
! 33: # ifdef HASH_TL
! 34: register hdr * result;
! 35: GET_HDR(h, result);
! 36: return(result);
! 37: # else
! 38: return(HDR_INNER(h));
! 39: # endif
! 40: }
! 41:
! 42: /* Routines to dynamically allocate collector data structures that will */
! 43: /* never be freed. */
! 44:
! 45: static ptr_t scratch_free_ptr = 0;
! 46:
! 47: ptr_t GC_scratch_end_ptr = 0;
! 48:
! 49: ptr_t GC_scratch_last_end_ptr = 0;
! 50: /* End point of last obtained scratch area */
! 51:
! 52: ptr_t GC_scratch_alloc(bytes)
! 53: register word bytes;
! 54: {
! 55: register ptr_t result = scratch_free_ptr;
! 56:
! 57: # ifdef ALIGN_DOUBLE
! 58: # define GRANULARITY (2 * sizeof(word))
! 59: # else
! 60: # define GRANULARITY sizeof(word)
! 61: # endif
! 62: bytes += GRANULARITY-1;
! 63: bytes &= ~(GRANULARITY-1);
! 64: scratch_free_ptr += bytes;
! 65: if (scratch_free_ptr <= GC_scratch_end_ptr) {
! 66: return(result);
! 67: }
! 68: {
! 69: word bytes_to_get = MINHINCR * HBLKSIZE;
! 70:
! 71: if (bytes_to_get <= bytes) {
! 72: /* Undo the damage, and get memory directly */
! 73: bytes_to_get = bytes;
! 74: # ifdef USE_MMAP
! 75: bytes_to_get += GC_page_size - 1;
! 76: bytes_to_get &= ~(GC_page_size - 1);
! 77: # endif
! 78: result = (ptr_t)GET_MEM(bytes_to_get);
! 79: scratch_free_ptr -= bytes;
! 80: GC_scratch_last_end_ptr = result + bytes;
! 81: return(result);
! 82: }
! 83: result = (ptr_t)GET_MEM(bytes_to_get);
! 84: if (result == 0) {
! 85: # ifdef PRINTSTATS
! 86: GC_printf0("Out of memory - trying to allocate less\n");
! 87: # endif
! 88: scratch_free_ptr -= bytes;
! 89: bytes_to_get = bytes;
! 90: # ifdef USE_MMAP
! 91: bytes_to_get += GC_page_size - 1;
! 92: bytes_to_get &= ~(GC_page_size - 1);
! 93: # endif
! 94: return((ptr_t)GET_MEM(bytes_to_get));
! 95: }
! 96: scratch_free_ptr = result;
! 97: GC_scratch_end_ptr = scratch_free_ptr + bytes_to_get;
! 98: GC_scratch_last_end_ptr = GC_scratch_end_ptr;
! 99: return(GC_scratch_alloc(bytes));
! 100: }
! 101: }
! 102:
! 103: static hdr * hdr_free_list = 0;
! 104:
! 105: /* Return an uninitialized header */
! 106: static hdr * alloc_hdr()
! 107: {
! 108: register hdr * result;
! 109:
! 110: if (hdr_free_list == 0) {
! 111: result = (hdr *) GC_scratch_alloc((word)(sizeof(hdr)));
! 112: } else {
! 113: result = hdr_free_list;
! 114: hdr_free_list = (hdr *) (result -> hb_next);
! 115: }
! 116: return(result);
! 117: }
! 118:
! 119: static void free_hdr(hhdr)
! 120: hdr * hhdr;
! 121: {
! 122: hhdr -> hb_next = (struct hblk *) hdr_free_list;
! 123: hdr_free_list = hhdr;
! 124: }
! 125:
! 126: void GC_init_headers()
! 127: {
! 128: register unsigned i;
! 129:
! 130: GC_all_nils = (bottom_index *)GC_scratch_alloc((word)sizeof(bottom_index));
! 131: BZERO(GC_all_nils, sizeof(bottom_index));
! 132: for (i = 0; i < TOP_SZ; i++) {
! 133: GC_top_index[i] = GC_all_nils;
! 134: }
! 135: }
! 136:
! 137: /* Make sure that there is a bottom level index block for address addr */
! 138: /* Return FALSE on failure. */
! 139: static GC_bool get_index(addr)
! 140: register word addr;
! 141: {
! 142: register word hi =
! 143: (word)(addr) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE);
! 144: register bottom_index * r;
! 145: register bottom_index * p;
! 146: register bottom_index ** prev;
! 147: # ifdef HASH_TL
! 148: register unsigned i = TL_HASH(hi);
! 149: register bottom_index * old;
! 150:
! 151: old = p = GC_top_index[i];
! 152: while(p != GC_all_nils) {
! 153: if (p -> key == hi) return(TRUE);
! 154: p = p -> hash_link;
! 155: }
! 156: r = (bottom_index*)GC_scratch_alloc((word)(sizeof (bottom_index)));
! 157: if (r == 0) return(FALSE);
! 158: BZERO(r, sizeof (bottom_index));
! 159: r -> hash_link = old;
! 160: GC_top_index[i] = r;
! 161: # else
! 162: if (GC_top_index[hi] != GC_all_nils) return(TRUE);
! 163: r = (bottom_index*)GC_scratch_alloc((word)(sizeof (bottom_index)));
! 164: if (r == 0) return(FALSE);
! 165: GC_top_index[hi] = r;
! 166: BZERO(r, sizeof (bottom_index));
! 167: # endif
! 168: r -> key = hi;
! 169: /* Add it to the list of bottom indices */
! 170: prev = &GC_all_bottom_indices;
! 171: while ((p = *prev) != 0 && p -> key < hi) prev = &(p -> asc_link);
! 172: r -> asc_link = p;
! 173: *prev = r;
! 174: return(TRUE);
! 175: }
! 176:
! 177: /* Install a header for block h. */
! 178: /* The header is uninitialized. */
! 179: /* Returns FALSE on failure. */
! 180: GC_bool GC_install_header(h)
! 181: register struct hblk * h;
! 182: {
! 183: hdr * result;
! 184:
! 185: if (!get_index((word) h)) return(FALSE);
! 186: result = alloc_hdr();
! 187: SET_HDR(h, result);
! 188: return(result != 0);
! 189: }
! 190:
! 191: /* Set up forwarding counts for block h of size sz */
! 192: GC_bool GC_install_counts(h, sz)
! 193: register struct hblk * h;
! 194: register word sz; /* bytes */
! 195: {
! 196: register struct hblk * hbp;
! 197: register int i;
! 198:
! 199: for (hbp = h; (char *)hbp < (char *)h + sz; hbp += BOTTOM_SZ) {
! 200: if (!get_index((word) hbp)) return(FALSE);
! 201: }
! 202: if (!get_index((word)h + sz - 1)) return(FALSE);
! 203: for (hbp = h + 1; (char *)hbp < (char *)h + sz; hbp += 1) {
! 204: i = HBLK_PTR_DIFF(hbp, h);
! 205: SET_HDR(hbp, (hdr *)(i > MAX_JUMP? MAX_JUMP : i));
! 206: }
! 207: return(TRUE);
! 208: }
! 209:
! 210: /* Remove the header for block h */
! 211: void GC_remove_header(h)
! 212: register struct hblk * h;
! 213: {
! 214: hdr ** ha;
! 215:
! 216: GET_HDR_ADDR(h, ha);
! 217: free_hdr(*ha);
! 218: *ha = 0;
! 219: }
! 220:
! 221: /* Remove forwarding counts for h */
! 222: void GC_remove_counts(h, sz)
! 223: register struct hblk * h;
! 224: register word sz; /* bytes */
! 225: {
! 226: register struct hblk * hbp;
! 227:
! 228: for (hbp = h+1; (char *)hbp < (char *)h + sz; hbp += 1) {
! 229: SET_HDR(hbp, 0);
! 230: }
! 231: }
! 232:
! 233: /* Apply fn to all allocated blocks */
! 234: /*VARARGS1*/
! 235: void GC_apply_to_all_blocks(fn, client_data)
! 236: void (*fn)(/* struct hblk *h, word client_data */);
! 237: word client_data;
! 238: {
! 239: register int j;
! 240: register bottom_index * index_p;
! 241:
! 242: for (index_p = GC_all_bottom_indices; index_p != 0;
! 243: index_p = index_p -> asc_link) {
! 244: for (j = BOTTOM_SZ-1; j >= 0;) {
! 245: if (!IS_FORWARDING_ADDR_OR_NIL(index_p->index[j])) {
! 246: if (index_p->index[j]->hb_map != GC_invalid_map) {
! 247: (*fn)(((struct hblk *)
! 248: (((index_p->key << LOG_BOTTOM_SZ) + (word)j)
! 249: << LOG_HBLKSIZE)),
! 250: client_data);
! 251: }
! 252: j--;
! 253: } else if (index_p->index[j] == 0) {
! 254: j--;
! 255: } else {
! 256: j -= (word)(index_p->index[j]);
! 257: }
! 258: }
! 259: }
! 260: }
! 261:
! 262: /* Get the next valid block whose address is at least h */
! 263: /* Return 0 if there is none. */
! 264: struct hblk * GC_next_block(h)
! 265: struct hblk * h;
! 266: {
! 267: register bottom_index * bi;
! 268: register word j = ((word)h >> LOG_HBLKSIZE) & (BOTTOM_SZ-1);
! 269:
! 270: GET_BI(h, bi);
! 271: if (bi == GC_all_nils) {
! 272: register word hi = (word)h >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE);
! 273: bi = GC_all_bottom_indices;
! 274: while (bi != 0 && bi -> key < hi) bi = bi -> asc_link;
! 275: j = 0;
! 276: }
! 277: while(bi != 0) {
! 278: while (j < BOTTOM_SZ) {
! 279: if (IS_FORWARDING_ADDR_OR_NIL(bi -> index[j])) {
! 280: j++;
! 281: } else {
! 282: if (bi->index[j]->hb_map != GC_invalid_map) {
! 283: return((struct hblk *)
! 284: (((bi -> key << LOG_BOTTOM_SZ) + j)
! 285: << LOG_HBLKSIZE));
! 286: } else {
! 287: j += divHBLKSZ(bi->index[j] -> hb_sz);
! 288: }
! 289: }
! 290: }
! 291: j = 0;
! 292: bi = bi -> asc_link;
! 293: }
! 294: return(0);
! 295: }
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