2 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3 * Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved.
4 * Copyright (c) 1997 by Silicon Graphics. All rights reserved.
5 * Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved.
7 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
8 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
10 * Permission is hereby granted to use or copy this program
11 * for any purpose, provided the above notices are retained on all copies.
12 * Permission to modify the code and to distribute modified code is granted,
13 * provided the above notices are retained, and a notice that the code was
14 * modified is included with the above copyright notice.
18 * This is mostly an internal header file. Typical clients should
19 * not use it. Clients that define their own object kinds with
20 * debugging allocators will probably want to include this, however.
21 * No attempt is made to keep the namespace clean. This should not be
22 * included from header files that are frequently included by clients.
30 # include "gc_backptr.h"
34 # define START_FLAG (word)0xfedcedcb
35 # define END_FLAG (word)0xbcdecdef
37 # define START_FLAG GC_WORD_C(0xFEDCEDCBfedcedcb)
38 # define END_FLAG GC_WORD_C(0xBCDECDEFbcdecdef)
40 /* Stored both one past the end of user object, and one before */
41 /* the end of the object as seen by the allocator. */
43 #if defined(KEEP_BACK_PTRS) || defined(PRINT_BLACK_LIST) \
44 || defined(MAKE_BACK_GRAPH)
45 /* Pointer "source"s that aren't real locations. */
46 /* Used in oh_back_ptr fields and as "source" */
47 /* argument to some marking functions. */
48 # define NOT_MARKED (ptr_t)0
49 # define MARKED_FOR_FINALIZATION ((ptr_t)(word)2)
50 /* Object was marked because it is finalizable. */
51 # define MARKED_FROM_REGISTER ((ptr_t)(word)4)
52 /* Object was marked from a register. Hence the */
53 /* source of the reference doesn't have an address. */
54 #endif /* KEEP_BACK_PTRS || PRINT_BLACK_LIST */
58 # if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
59 /* We potentially keep two different kinds of back */
60 /* pointers. KEEP_BACK_PTRS stores a single back */
61 /* pointer in each reachable object to allow reporting */
62 /* of why an object was retained. MAKE_BACK_GRAPH */
63 /* builds a graph containing the inverse of all */
64 /* "points-to" edges including those involving */
65 /* objects that have just become unreachable. This */
66 /* allows detection of growing chains of unreachable */
67 /* objects. It may be possible to eventually combine */
68 /* both, but for now we keep them separate. Both */
69 /* kinds of back pointers are hidden using the */
70 /* following macros. In both cases, the plain version */
71 /* is constrained to have an least significant bit of 1, */
72 /* to allow it to be distinguished from a free list */
73 /* link. This means the plain version must have an */
75 /* Note that blocks dropped by black-listing will */
76 /* also have the lsb clear once debugging has */
78 /* We're careful never to overwrite a value with lsb 0. */
80 /* Fudge back pointer to be even. */
81 # define HIDE_BACK_PTR(p) GC_HIDE_POINTER(~1 & (GC_word)(p))
83 # define HIDE_BACK_PTR(p) GC_HIDE_POINTER(p)
85 # ifdef KEEP_BACK_PTRS
86 GC_hidden_pointer oh_back_ptr;
88 # ifdef MAKE_BACK_GRAPH
89 GC_hidden_pointer oh_bg_ptr;
91 # if defined(KEEP_BACK_PTRS) != defined(MAKE_BACK_GRAPH)
92 /* Keep double-pointer-sized alignment. */
96 const char * oh_string; /* object descriptor string */
97 word oh_int; /* object descriptor integers */
99 struct callinfo oh_ci[NFRAMES];
101 # ifndef SHORT_DBG_HDRS
102 word oh_sz; /* Original malloc arg. */
103 word oh_sf; /* start flag */
104 # endif /* SHORT_DBG_HDRS */
106 /* The size of the above structure is assumed not to de-align things, */
107 /* and to be a multiple of the word length. */
109 #ifdef SHORT_DBG_HDRS
110 # define DEBUG_BYTES (sizeof (oh))
111 # define UNCOLLECTABLE_DEBUG_BYTES DEBUG_BYTES
113 /* Add space for END_FLAG, but use any extra space that was already */
114 /* added to catch off-the-end pointers. */
115 /* For uncollectable objects, the extra byte is not added. */
116 # define UNCOLLECTABLE_DEBUG_BYTES (sizeof (oh) + sizeof (word))
117 # define DEBUG_BYTES (UNCOLLECTABLE_DEBUG_BYTES - EXTRA_BYTES)
120 /* Round bytes to words without adding extra byte at end. */
121 #define SIMPLE_ROUNDED_UP_WORDS(n) BYTES_TO_WORDS((n) + WORDS_TO_BYTES(1) - 1)
123 /* ADD_CALL_CHAIN stores a (partial) call chain into an object */
124 /* header. It may be called with or without the allocation */
126 /* PRINT_CALL_CHAIN prints the call chain stored in an object */
127 /* to stderr. It requires that we do not hold the lock. */
128 #if defined(SAVE_CALL_CHAIN)
130 GC_INNER void GC_save_callers(struct callinfo info[NFRAMES]);
131 GC_INNER void GC_print_callers(struct callinfo info[NFRAMES]);
132 # define ADD_CALL_CHAIN(base, ra) GC_save_callers(((oh *)(base)) -> oh_ci)
133 # define PRINT_CALL_CHAIN(base) GC_print_callers(((oh *)(base)) -> oh_ci)
134 #elif defined(GC_ADD_CALLER)
136 GC_INNER void GC_print_callers(struct callinfo info[NFRAMES]);
137 # define ADD_CALL_CHAIN(base, ra) ((oh *)(base)) -> oh_ci[0].ci_pc = (ra)
138 # define PRINT_CALL_CHAIN(base) GC_print_callers(((oh *)(base)) -> oh_ci)
140 # define ADD_CALL_CHAIN(base, ra)
141 # define PRINT_CALL_CHAIN(base)
150 /* Check whether object with base pointer p has debugging info */
151 /* p is assumed to point to a legitimate object in our part */
153 #ifdef SHORT_DBG_HDRS
154 # define GC_has_other_debug_info(p) 1
156 GC_INNER int GC_has_other_debug_info(ptr_t p);
159 #if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
160 # define GC_HAS_DEBUG_INFO(p) \
161 ((*((word *)p) & 1) && GC_has_other_debug_info(p) > 0)
163 # define GC_HAS_DEBUG_INFO(p) (GC_has_other_debug_info(p) > 0)
166 #endif /* _DBG_MLC_H */