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Annotation of OpenXM_contrib2/asir2000/gc5.3/headers.c, Revision 1.1.1.1

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: /* GC_scratch_last_end_ptr is end point of last obtained scratch area.  */
                     54: /* GC_scratch_end_ptr is end point of current scratch area.            */
                     55:
                     56: ptr_t GC_scratch_alloc(bytes)
                     57: register word bytes;
                     58: {
                     59:     register ptr_t result = scratch_free_ptr;
                     60:
                     61: #   ifdef ALIGN_DOUBLE
                     62: #      define GRANULARITY (2 * sizeof(word))
                     63: #   else
                     64: #      define GRANULARITY sizeof(word)
                     65: #   endif
                     66:     bytes += GRANULARITY-1;
                     67:     bytes &= ~(GRANULARITY-1);
                     68:     scratch_free_ptr += bytes;
                     69:     if (scratch_free_ptr <= GC_scratch_end_ptr) {
                     70:         return(result);
                     71:     }
                     72:     {
                     73:         word bytes_to_get = MINHINCR * HBLKSIZE;
                     74:
                     75:         if (bytes_to_get <= bytes) {
                     76:           /* Undo the damage, and get memory directly */
                     77:            bytes_to_get = bytes;
                     78: #          ifdef USE_MMAP
                     79:                bytes_to_get += GC_page_size - 1;
                     80:                bytes_to_get &= ~(GC_page_size - 1);
                     81: #          endif
                     82:            result = (ptr_t)GET_MEM(bytes_to_get);
                     83:             scratch_free_ptr -= bytes;
                     84:            GC_scratch_last_end_ptr = result + bytes;
                     85:             return(result);
                     86:         }
                     87:         result = (ptr_t)GET_MEM(bytes_to_get);
                     88:         if (result == 0) {
                     89: #          ifdef PRINTSTATS
                     90:                 GC_printf0("Out of memory - trying to allocate less\n");
                     91: #          endif
                     92:             scratch_free_ptr -= bytes;
                     93:            bytes_to_get = bytes;
                     94: #          ifdef USE_MMAP
                     95:                bytes_to_get += GC_page_size - 1;
                     96:                bytes_to_get &= ~(GC_page_size - 1);
                     97: #          endif
                     98:             return((ptr_t)GET_MEM(bytes_to_get));
                     99:         }
                    100:         scratch_free_ptr = result;
                    101:         GC_scratch_end_ptr = scratch_free_ptr + bytes_to_get;
                    102:         GC_scratch_last_end_ptr = GC_scratch_end_ptr;
                    103:         return(GC_scratch_alloc(bytes));
                    104:     }
                    105: }
                    106:
                    107: static hdr * hdr_free_list = 0;
                    108:
                    109: /* Return an uninitialized header */
                    110: static hdr * alloc_hdr()
                    111: {
                    112:     register hdr * result;
                    113:
                    114:     if (hdr_free_list == 0) {
                    115:         result = (hdr *) GC_scratch_alloc((word)(sizeof(hdr)));
                    116:     } else {
                    117:         result = hdr_free_list;
                    118:         hdr_free_list = (hdr *) (result -> hb_next);
                    119:     }
                    120:     return(result);
                    121: }
                    122:
                    123: static void free_hdr(hhdr)
                    124: hdr * hhdr;
                    125: {
                    126:     hhdr -> hb_next = (struct hblk *) hdr_free_list;
                    127:     hdr_free_list = hhdr;
                    128: }
                    129:
                    130: hdr * GC_invalid_header;
                    131:
                    132: #ifdef USE_HDR_CACHE
                    133:   word GC_hdr_cache_hits = 0;
                    134:   word GC_hdr_cache_misses = 0;
                    135: #endif
                    136:
                    137: void GC_init_headers()
                    138: {
                    139:     register unsigned i;
                    140:
                    141:     GC_all_nils = (bottom_index *)GC_scratch_alloc((word)sizeof(bottom_index));
                    142:     BZERO(GC_all_nils, sizeof(bottom_index));
                    143:     for (i = 0; i < TOP_SZ; i++) {
                    144:         GC_top_index[i] = GC_all_nils;
                    145:     }
                    146:     GC_invalid_header = alloc_hdr();
                    147:     GC_invalidate_map(GC_invalid_header);
                    148: }
                    149:
                    150: /* Make sure that there is a bottom level index block for address addr  */
                    151: /* Return FALSE on failure.                                            */
                    152: static GC_bool get_index(addr)
                    153: word addr;
                    154: {
                    155:     word hi = (word)(addr) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE);
                    156:     bottom_index * r;
                    157:     bottom_index * p;
                    158:     bottom_index ** prev;
                    159:     bottom_index *pi;
                    160:
                    161: #   ifdef HASH_TL
                    162:       unsigned i = TL_HASH(hi);
                    163:       bottom_index * old;
                    164:
                    165:       old = p = GC_top_index[i];
                    166:       while(p != GC_all_nils) {
                    167:           if (p -> key == hi) return(TRUE);
                    168:           p = p -> hash_link;
                    169:       }
                    170:       r = (bottom_index*)GC_scratch_alloc((word)(sizeof (bottom_index)));
                    171:       if (r == 0) return(FALSE);
                    172:       BZERO(r, sizeof (bottom_index));
                    173:       r -> hash_link = old;
                    174:       GC_top_index[i] = r;
                    175: #   else
                    176:       if (GC_top_index[hi] != GC_all_nils) return(TRUE);
                    177:       r = (bottom_index*)GC_scratch_alloc((word)(sizeof (bottom_index)));
                    178:       if (r == 0) return(FALSE);
                    179:       GC_top_index[hi] = r;
                    180:       BZERO(r, sizeof (bottom_index));
                    181: #   endif
                    182:     r -> key = hi;
                    183:     /* Add it to the list of bottom indices */
                    184:       prev = &GC_all_bottom_indices;   /* pointer to p */
                    185:       pi = 0;                          /* bottom_index preceding p */
                    186:       while ((p = *prev) != 0 && p -> key < hi) {
                    187:        pi = p;
                    188:        prev = &(p -> asc_link);
                    189:       }
                    190:       r -> desc_link = pi;
                    191:       if (0 == p) {
                    192:        GC_all_bottom_indices_end = r;
                    193:       } else {
                    194:        p -> desc_link = r;
                    195:       }
                    196:       r -> asc_link = p;
                    197:       *prev = r;
                    198:     return(TRUE);
                    199: }
                    200:
                    201: /* Install a header for block h.       */
                    202: /* The header is uninitialized.                */
                    203: /* Returns the header or 0 on failure. */
                    204: struct hblkhdr * GC_install_header(h)
                    205: register struct hblk * h;
                    206: {
                    207:     hdr * result;
                    208:
                    209:     if (!get_index((word) h)) return(FALSE);
                    210:     result = alloc_hdr();
                    211:     SET_HDR(h, result);
                    212: #   ifdef USE_MUNMAP
                    213:        result -> hb_last_reclaimed = GC_gc_no;
                    214: #   endif
                    215:     return(result);
                    216: }
                    217:
                    218: /* Set up forwarding counts for block h of size sz */
                    219: GC_bool GC_install_counts(h, sz)
                    220: register struct hblk * h;
                    221: register word sz; /* bytes */
                    222: {
                    223:     register struct hblk * hbp;
                    224:     register int i;
                    225:
                    226:     for (hbp = h; (char *)hbp < (char *)h + sz; hbp += BOTTOM_SZ) {
                    227:         if (!get_index((word) hbp)) return(FALSE);
                    228:     }
                    229:     if (!get_index((word)h + sz - 1)) return(FALSE);
                    230:     for (hbp = h + 1; (char *)hbp < (char *)h + sz; hbp += 1) {
                    231:         i = HBLK_PTR_DIFF(hbp, h);
                    232:         SET_HDR(hbp, (hdr *)(i > MAX_JUMP? MAX_JUMP : i));
                    233:     }
                    234:     return(TRUE);
                    235: }
                    236:
                    237: /* Remove the header for block h */
                    238: void GC_remove_header(h)
                    239: register struct hblk * h;
                    240: {
                    241:     hdr ** ha;
                    242:
                    243:     GET_HDR_ADDR(h, ha);
                    244:     free_hdr(*ha);
                    245:     *ha = 0;
                    246: }
                    247:
                    248: /* Remove forwarding counts for h */
                    249: void GC_remove_counts(h, sz)
                    250: register struct hblk * h;
                    251: register word sz; /* bytes */
                    252: {
                    253:     register struct hblk * hbp;
                    254:
                    255:     for (hbp = h+1; (char *)hbp < (char *)h + sz; hbp += 1) {
                    256:         SET_HDR(hbp, 0);
                    257:     }
                    258: }
                    259:
                    260: /* Apply fn to all allocated blocks */
                    261: /*VARARGS1*/
                    262: void GC_apply_to_all_blocks(fn, client_data)
                    263: void (*fn)(/* struct hblk *h, word client_data */);
                    264: word client_data;
                    265: {
                    266:     register int j;
                    267:     register bottom_index * index_p;
                    268:
                    269:     for (index_p = GC_all_bottom_indices; index_p != 0;
                    270:          index_p = index_p -> asc_link) {
                    271:         for (j = BOTTOM_SZ-1; j >= 0;) {
                    272:             if (!IS_FORWARDING_ADDR_OR_NIL(index_p->index[j])) {
                    273:                 if (index_p->index[j]->hb_map != GC_invalid_map) {
                    274:                     (*fn)(((struct hblk *)
                    275:                              (((index_p->key << LOG_BOTTOM_SZ) + (word)j)
                    276:                               << LOG_HBLKSIZE)),
                    277:                           client_data);
                    278:                 }
                    279:                 j--;
                    280:              } else if (index_p->index[j] == 0) {
                    281:                 j--;
                    282:              } else {
                    283:                 j -= (word)(index_p->index[j]);
                    284:              }
                    285:          }
                    286:      }
                    287: }
                    288:
                    289: /* Get the next valid block whose address is at least h        */
                    290: /* Return 0 if there is none.                          */
                    291: struct hblk * GC_next_used_block(h)
                    292: struct hblk * h;
                    293: {
                    294:     register bottom_index * bi;
                    295:     register word j = ((word)h >> LOG_HBLKSIZE) & (BOTTOM_SZ-1);
                    296:
                    297:     GET_BI(h, bi);
                    298:     if (bi == GC_all_nils) {
                    299:         register word hi = (word)h >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE);
                    300:         bi = GC_all_bottom_indices;
                    301:         while (bi != 0 && bi -> key < hi) bi = bi -> asc_link;
                    302:         j = 0;
                    303:     }
                    304:     while(bi != 0) {
                    305:         while (j < BOTTOM_SZ) {
                    306:            hdr * hhdr = bi -> index[j];
                    307:             if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
                    308:                 j++;
                    309:             } else {
                    310:                 if (hhdr->hb_map != GC_invalid_map) {
                    311:                     return((struct hblk *)
                    312:                              (((bi -> key << LOG_BOTTOM_SZ) + j)
                    313:                               << LOG_HBLKSIZE));
                    314:                 } else {
                    315:                     j += divHBLKSZ(hhdr -> hb_sz);
                    316:                 }
                    317:             }
                    318:         }
                    319:         j = 0;
                    320:         bi = bi -> asc_link;
                    321:     }
                    322:     return(0);
                    323: }
                    324:
                    325: /* Get the last (highest address) block whose address is       */
                    326: /* at most h.  Return 0 if there is none.                      */
                    327: /* Unlike the above, this may return a free block.             */
                    328: struct hblk * GC_prev_block(h)
                    329: struct hblk * h;
                    330: {
                    331:     register bottom_index * bi;
                    332:     register signed_word j = ((word)h >> LOG_HBLKSIZE) & (BOTTOM_SZ-1);
                    333:
                    334:     GET_BI(h, bi);
                    335:     if (bi == GC_all_nils) {
                    336:         register word hi = (word)h >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE);
                    337:         bi = GC_all_bottom_indices_end;
                    338:         while (bi != 0 && bi -> key > hi) bi = bi -> desc_link;
                    339:         j = BOTTOM_SZ - 1;
                    340:     }
                    341:     while(bi != 0) {
                    342:         while (j >= 0) {
                    343:            hdr * hhdr = bi -> index[j];
                    344:            if (0 == hhdr) {
                    345:                --j;
                    346:             } else if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
                    347:                 j -= (signed_word)hhdr;
                    348:             } else {
                    349:                 return((struct hblk *)
                    350:                           (((bi -> key << LOG_BOTTOM_SZ) + j)
                    351:                               << LOG_HBLKSIZE));
                    352:             }
                    353:         }
                    354:         j = BOTTOM_SZ - 1;
                    355:         bi = bi -> desc_link;
                    356:     }
                    357:     return(0);
                    358: }

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