* stmt.c (expand_anon_union_decl): When any of the elements of the
[official-gcc.git] / boehm-gc / gc_hdrs.h
blob2f2d1bf9b8aa5f16b5b899298d8e3c8a33ed14ff
1 /*
2 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3 * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
5 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
6 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
8 * Permission is hereby granted to use or copy this program
9 * for any purpose, provided the above notices are retained on all copies.
10 * Permission to modify the code and to distribute modified code is granted,
11 * provided the above notices are retained, and a notice that the code was
12 * modified is included with the above copyright notice.
14 /* Boehm, July 11, 1995 11:54 am PDT */
15 # ifndef GC_HEADERS_H
16 # define GC_HEADERS_H
17 typedef struct hblkhdr hdr;
19 # if CPP_WORDSZ != 32 && CPP_WORDSZ < 36
20 --> Get a real machine.
21 # endif
24 * The 2 level tree data structure that is used to find block headers.
25 * If there are more than 32 bits in a pointer, the top level is a hash
26 * table.
29 # if CPP_WORDSZ > 32
30 # define HASH_TL
31 # endif
33 /* Define appropriate out-degrees for each of the two tree levels */
34 # ifdef SMALL_CONFIG
35 # define LOG_BOTTOM_SZ 11
36 /* Keep top index size reasonable with smaller blocks. */
37 # else
38 # define LOG_BOTTOM_SZ 10
39 # endif
40 # ifndef HASH_TL
41 # define LOG_TOP_SZ (WORDSZ - LOG_BOTTOM_SZ - LOG_HBLKSIZE)
42 # else
43 # define LOG_TOP_SZ 11
44 # endif
45 # define TOP_SZ (1 << LOG_TOP_SZ)
46 # define BOTTOM_SZ (1 << LOG_BOTTOM_SZ)
48 typedef struct bi {
49 hdr * index[BOTTOM_SZ];
51 * The bottom level index contains one of three kinds of values:
52 * 0 means we're not responsible for this block.
53 * 1 < (long)X <= MAX_JUMP means the block starts at least
54 * X * HBLKSIZE bytes before the current address.
55 * A valid pointer points to a hdr structure. (The above can't be
56 * valid pointers due to the GET_MEM return convention.)
58 struct bi * asc_link; /* All indices are linked in */
59 /* ascending order. */
60 word key; /* high order address bits. */
61 # ifdef HASH_TL
62 struct bi * hash_link; /* Hash chain link. */
63 # endif
64 } bottom_index;
66 /* extern bottom_index GC_all_nils; - really part of GC_arrays */
68 /* extern bottom_index * GC_top_index []; - really part of GC_arrays */
69 /* Each entry points to a bottom_index. */
70 /* On a 32 bit machine, it points to */
71 /* the index for a set of high order */
72 /* bits equal to the index. For longer */
73 /* addresses, we hash the high order */
74 /* bits to compute the index in */
75 /* GC_top_index, and each entry points */
76 /* to a hash chain. */
77 /* The last entry in each chain is */
78 /* GC_all_nils. */
81 # define MAX_JUMP (HBLKSIZE - 1)
83 # define HDR_FROM_BI(bi, p) \
84 ((bi)->index[((word)(p) >> LOG_HBLKSIZE) & (BOTTOM_SZ - 1)])
85 # ifndef HASH_TL
86 # define BI(p) (GC_top_index \
87 [(word)(p) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE)])
88 # define HDR_INNER(p) HDR_FROM_BI(BI(p),p)
89 # ifdef SMALL_CONFIG
90 # define HDR(p) GC_find_header((ptr_t)(p))
91 # else
92 # define HDR(p) HDR_INNER(p)
93 # endif
94 # define GET_BI(p, bottom_indx) (bottom_indx) = BI(p)
95 # define GET_HDR(p, hhdr) (hhdr) = HDR(p)
96 # define SET_HDR(p, hhdr) HDR_INNER(p) = (hhdr)
97 # define GET_HDR_ADDR(p, ha) (ha) = &(HDR_INNER(p))
98 # else /* hash */
99 /* Hash function for tree top level */
100 # define TL_HASH(hi) ((hi) & (TOP_SZ - 1))
101 /* Set bottom_indx to point to the bottom index for address p */
102 # define GET_BI(p, bottom_indx) \
104 register word hi = \
105 (word)(p) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE); \
106 register bottom_index * _bi = GC_top_index[TL_HASH(hi)]; \
108 while (_bi -> key != hi && _bi != GC_all_nils) \
109 _bi = _bi -> hash_link; \
110 (bottom_indx) = _bi; \
112 # define GET_HDR_ADDR(p, ha) \
114 register bottom_index * bi; \
116 GET_BI(p, bi); \
117 (ha) = &(HDR_FROM_BI(bi, p)); \
119 # define GET_HDR(p, hhdr) { register hdr ** _ha; GET_HDR_ADDR(p, _ha); \
120 (hhdr) = *_ha; }
121 # define SET_HDR(p, hhdr) { register hdr ** _ha; GET_HDR_ADDR(p, _ha); \
122 *_ha = (hhdr); }
123 # define HDR(p) GC_find_header((ptr_t)(p))
124 # endif
126 /* Is the result a forwarding address to someplace closer to the */
127 /* beginning of the block or NIL? */
128 # define IS_FORWARDING_ADDR_OR_NIL(hhdr) ((unsigned long) (hhdr) <= MAX_JUMP)
130 /* Get an HBLKSIZE aligned address closer to the beginning of the block */
131 /* h. Assumes hhdr == HDR(h) and IS_FORWARDING_ADDR(hhdr). */
132 # define FORWARDED_ADDR(h, hhdr) ((struct hblk *)(h) - (unsigned long)(hhdr))
133 # endif /* GC_HEADERS_H */