2005-08-27 Paul Brook <paul@codesourcery.com>
[official-gcc.git] / boehm-gc / new_hblk.c
blobe5580e4ca218d9770f7dcf171bf4cc61420852c2
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) 2000 by Hewlett-Packard Company. All rights reserved.
6 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
7 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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.
15 * This file contains the functions:
16 * ptr_t GC_build_flXXX(h, old_fl)
17 * void GC_new_hblk(n)
19 /* Boehm, May 19, 1994 2:09 pm PDT */
22 # include <stdio.h>
23 # include "private/gc_priv.h"
25 #ifndef SMALL_CONFIG
27 * Build a free list for size 1 objects inside hblk h. Set the last link to
28 * be ofl. Return a pointer tpo the first free list entry.
30 ptr_t GC_build_fl1(h, ofl)
31 struct hblk *h;
32 ptr_t ofl;
34 register word * p = h -> hb_body;
35 register word * lim = (word *)(h + 1);
37 p[0] = (word)ofl;
38 p[1] = (word)(p);
39 p[2] = (word)(p+1);
40 p[3] = (word)(p+2);
41 p += 4;
42 for (; p < lim; p += 4) {
43 p[0] = (word)(p-1);
44 p[1] = (word)(p);
45 p[2] = (word)(p+1);
46 p[3] = (word)(p+2);
48 return((ptr_t)(p-1));
51 /* The same for size 2 cleared objects */
52 ptr_t GC_build_fl_clear2(h, ofl)
53 struct hblk *h;
54 ptr_t ofl;
56 register word * p = h -> hb_body;
57 register word * lim = (word *)(h + 1);
59 p[0] = (word)ofl;
60 p[1] = 0;
61 p[2] = (word)p;
62 p[3] = 0;
63 p += 4;
64 for (; p < lim; p += 4) {
65 p[0] = (word)(p-2);
66 p[1] = 0;
67 p[2] = (word)p;
68 p[3] = 0;
70 return((ptr_t)(p-2));
73 /* The same for size 3 cleared objects */
74 ptr_t GC_build_fl_clear3(h, ofl)
75 struct hblk *h;
76 ptr_t ofl;
78 register word * p = h -> hb_body;
79 register word * lim = (word *)(h + 1) - 2;
81 p[0] = (word)ofl;
82 p[1] = 0;
83 p[2] = 0;
84 p += 3;
85 for (; p < lim; p += 3) {
86 p[0] = (word)(p-3);
87 p[1] = 0;
88 p[2] = 0;
90 return((ptr_t)(p-3));
93 /* The same for size 4 cleared objects */
94 ptr_t GC_build_fl_clear4(h, ofl)
95 struct hblk *h;
96 ptr_t ofl;
98 register word * p = h -> hb_body;
99 register word * lim = (word *)(h + 1);
101 p[0] = (word)ofl;
102 p[1] = 0;
103 p[2] = 0;
104 p[3] = 0;
105 p += 4;
106 for (; p < lim; p += 4) {
107 PREFETCH_FOR_WRITE((ptr_t)(p+64));
108 p[0] = (word)(p-4);
109 p[1] = 0;
110 CLEAR_DOUBLE(p+2);
112 return((ptr_t)(p-4));
115 /* The same for size 2 uncleared objects */
116 ptr_t GC_build_fl2(h, ofl)
117 struct hblk *h;
118 ptr_t ofl;
120 register word * p = h -> hb_body;
121 register word * lim = (word *)(h + 1);
123 p[0] = (word)ofl;
124 p[2] = (word)p;
125 p += 4;
126 for (; p < lim; p += 4) {
127 p[0] = (word)(p-2);
128 p[2] = (word)p;
130 return((ptr_t)(p-2));
133 /* The same for size 4 uncleared objects */
134 ptr_t GC_build_fl4(h, ofl)
135 struct hblk *h;
136 ptr_t ofl;
138 register word * p = h -> hb_body;
139 register word * lim = (word *)(h + 1);
141 p[0] = (word)ofl;
142 p[4] = (word)p;
143 p += 8;
144 for (; p < lim; p += 8) {
145 PREFETCH_FOR_WRITE((ptr_t)(p+64));
146 p[0] = (word)(p-4);
147 p[4] = (word)p;
149 return((ptr_t)(p-4));
152 #endif /* !SMALL_CONFIG */
155 /* Build a free list for objects of size sz inside heap block h. */
156 /* Clear objects inside h if clear is set. Add list to the end of */
157 /* the free list we build. Return the new free list. */
158 /* This could be called without the main GC lock, if we ensure that */
159 /* there is no concurrent collection which might reclaim objects that */
160 /* we have not yet allocated. */
161 ptr_t GC_build_fl(h, sz, clear, list)
162 struct hblk *h;
163 word sz;
164 GC_bool clear;
165 ptr_t list;
167 word *p, *prev;
168 word *last_object; /* points to last object in new hblk */
170 /* Do a few prefetches here, just because its cheap. */
171 /* If we were more serious about it, these should go inside */
172 /* the loops. But write prefetches usually don't seem to */
173 /* matter much. */
174 PREFETCH_FOR_WRITE((ptr_t)h);
175 PREFETCH_FOR_WRITE((ptr_t)h + 128);
176 PREFETCH_FOR_WRITE((ptr_t)h + 256);
177 PREFETCH_FOR_WRITE((ptr_t)h + 378);
178 /* Handle small objects sizes more efficiently. For larger objects */
179 /* the difference is less significant. */
180 # ifndef SMALL_CONFIG
181 switch (sz) {
182 case 1: return GC_build_fl1(h, list);
183 case 2: if (clear) {
184 return GC_build_fl_clear2(h, list);
185 } else {
186 return GC_build_fl2(h, list);
188 case 3: if (clear) {
189 return GC_build_fl_clear3(h, list);
190 } else {
191 /* It's messy to do better than the default here. */
192 break;
194 case 4: if (clear) {
195 return GC_build_fl_clear4(h, list);
196 } else {
197 return GC_build_fl4(h, list);
199 default:
200 break;
202 # endif /* !SMALL_CONFIG */
204 /* Clear the page if necessary. */
205 if (clear) BZERO(h, HBLKSIZE);
207 /* Add objects to free list */
208 p = &(h -> hb_body[sz]); /* second object in *h */
209 prev = &(h -> hb_body[0]); /* One object behind p */
210 last_object = (word *)((char *)h + HBLKSIZE);
211 last_object -= sz;
212 /* Last place for last object to start */
214 /* make a list of all objects in *h with head as last object */
215 while (p <= last_object) {
216 /* current object's link points to last object */
217 obj_link(p) = (ptr_t)prev;
218 prev = p;
219 p += sz;
221 p -= sz; /* p now points to last object */
224 * put p (which is now head of list of objects in *h) as first
225 * pointer in the appropriate free list for this size.
227 obj_link(h -> hb_body) = list;
228 return ((ptr_t)p);
232 * Allocate a new heapblock for small objects of size n.
233 * Add all of the heapblock's objects to the free list for objects
234 * of that size.
235 * Set all mark bits if objects are uncollectable.
236 * Will fail to do anything if we are out of memory.
238 void GC_new_hblk(sz, kind)
239 register word sz;
240 int kind;
242 register struct hblk *h; /* the new heap block */
243 register GC_bool clear = GC_obj_kinds[kind].ok_init;
245 # ifdef PRINTSTATS
246 if ((sizeof (struct hblk)) > HBLKSIZE) {
247 ABORT("HBLK SZ inconsistency");
249 # endif
250 if (GC_debugging_started) clear = TRUE;
252 /* Allocate a new heap block */
253 h = GC_allochblk(sz, kind, 0);
254 if (h == 0) return;
256 /* Mark all objects if appropriate. */
257 if (IS_UNCOLLECTABLE(kind)) GC_set_hdr_marks(HDR(h));
259 /* Build the free list */
260 GC_obj_kinds[kind].ok_freelist[sz] =
261 GC_build_fl(h, sz, clear, GC_obj_kinds[kind].ok_freelist[sz]);