Annotation of OpenXM_contrib/gc/headers.c, Revision 1.1.1.1
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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