source: trunk/gc6.8/include/gc.h@ 202

Last change on this file since 202 was 132, checked in by cinc, 19 years ago

Boehm-Demers-Weiser garbage collector. Single-threaded for OS/2.
File size: 43.4 KB
Line 
1/*
2 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3 * Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved.
4 * Copyright 1996-1999 by Silicon Graphics. All rights reserved.
5 * Copyright 1999 by Hewlett-Packard Company. All rights reserved.
6 *
7 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
8 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
9 *
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.
15 */
16
17/*
18 * Note that this defines a large number of tuning hooks, which can
19 * safely be ignored in nearly all cases. For normal use it suffices
20 * to call only GC_MALLOC and perhaps GC_REALLOC.
21 * For better performance, also look at GC_MALLOC_ATOMIC, and
22 * GC_enable_incremental. If you need an action to be performed
23 * immediately before an object is collected, look at GC_register_finalizer.
24 * If you are using Solaris threads, look at the end of this file.
25 * Everything else is best ignored unless you encounter performance
26 * problems.
27 */
28
29#ifndef _GC_H
30
31# define _GC_H
32
33# include "gc_config_macros.h"
34
35# if defined(__STDC__) || defined(__cplusplus) || defined(_AIX)
36# define GC_PROTO(args) args
37 typedef void * GC_PTR;
38# define GC_CONST const
39# else
40# define GC_PROTO(args) ()
41 typedef char * GC_PTR;
42# define GC_CONST
43# endif
44
45# ifdef __cplusplus
46 extern "C" {
47# endif
48
49
50/* Define word and signed_word to be unsigned and signed types of the */
51/* size as char * or void *. There seems to be no way to do this */
52/* even semi-portably. The following is probably no better/worse */
53/* than almost anything else. */
54/* The ANSI standard suggests that size_t and ptr_diff_t might be */
55/* better choices. But those had incorrect definitions on some older */
56/* systems. Notably "typedef int size_t" is WRONG. */
57#ifndef _WIN64
58 typedef unsigned long GC_word;
59 typedef long GC_signed_word;
60#else
61 /* Win64 isn't really supported yet, but this is the first step. And */
62 /* it might cause error messages to show up in more plausible places. */
63 /* This needs basetsd.h, which is included by windows.h. */
64 typedef ULONG_PTR GC_word;
65 typedef LONG_PTR GC_word;
66#endif
67
68/* Public read-only variables */
69
70GC_API GC_word GC_gc_no;/* Counter incremented per collection. */
71 /* Includes empty GCs at startup. */
72
73GC_API int GC_parallel; /* GC is parallelized for performance on */
74 /* multiprocessors. Currently set only */
75 /* implicitly if collector is built with */
76 /* -DPARALLEL_MARK and if either: */
77 /* Env variable GC_NPROC is set to > 1, or */
78 /* GC_NPROC is not set and this is an MP. */
79 /* If GC_parallel is set, incremental */
80 /* collection is only partially functional, */
81 /* and may not be desirable. */
82
83
84/* Public R/W variables */
85
86GC_API GC_PTR (*GC_oom_fn) GC_PROTO((size_t bytes_requested));
87 /* When there is insufficient memory to satisfy */
88 /* an allocation request, we return */
89 /* (*GC_oom_fn)(). By default this just */
90 /* returns 0. */
91 /* If it returns, it must return 0 or a valid */
92 /* pointer to a previously allocated heap */
93 /* object. */
94
95GC_API int GC_find_leak;
96 /* Do not actually garbage collect, but simply */
97 /* report inaccessible memory that was not */
98 /* deallocated with GC_free. Initial value */
99 /* is determined by FIND_LEAK macro. */
100
101GC_API int GC_all_interior_pointers;
102 /* Arrange for pointers to object interiors to */
103 /* be recognized as valid. May not be changed */
104 /* after GC initialization. */
105 /* Initial value is determined by */
106 /* -DALL_INTERIOR_POINTERS. */
107 /* Unless DONT_ADD_BYTE_AT_END is defined, this */
108 /* also affects whether sizes are increased by */
109 /* at least a byte to allow "off the end" */
110 /* pointer recognition. */
111 /* MUST BE 0 or 1. */
112
113GC_API int GC_quiet; /* Disable statistics output. Only matters if */
114 /* collector has been compiled with statistics */
115 /* enabled. This involves a performance cost, */
116 /* and is thus not the default. */
117
118GC_API int GC_finalize_on_demand;
119 /* If nonzero, finalizers will only be run in */
120 /* response to an explicit GC_invoke_finalizers */
121 /* call. The default is determined by whether */
122 /* the FINALIZE_ON_DEMAND macro is defined */
123 /* when the collector is built. */
124
125GC_API int GC_java_finalization;
126 /* Mark objects reachable from finalizable */
127 /* objects in a separate postpass. This makes */
128 /* it a bit safer to use non-topologically- */
129 /* ordered finalization. Default value is */
130 /* determined by JAVA_FINALIZATION macro. */
131
132GC_API void (* GC_finalizer_notifier) GC_PROTO((void));
133 /* Invoked by the collector when there are */
134 /* objects to be finalized. Invoked at most */
135 /* once per GC cycle. Never invoked unless */
136 /* GC_finalize_on_demand is set. */
137 /* Typically this will notify a finalization */
138 /* thread, which will call GC_invoke_finalizers */
139 /* in response. */
140
141GC_API int GC_dont_gc; /* != 0 ==> Dont collect. In versions 6.2a1+, */
142 /* this overrides explicit GC_gcollect() calls. */
143 /* Used as a counter, so that nested enabling */
144 /* and disabling work correctly. Should */
145 /* normally be updated with GC_enable() and */
146 /* GC_disable() calls. */
147 /* Direct assignment to GC_dont_gc is */
148 /* deprecated. */
149
150GC_API int GC_dont_expand;
151 /* Dont expand heap unless explicitly requested */
152 /* or forced to. */
153
154GC_API int GC_use_entire_heap;
155 /* Causes the nonincremental collector to use the */
156 /* entire heap before collecting. This was the only */
157 /* option for GC versions < 5.0. This sometimes */
158 /* results in more large block fragmentation, since */
159 /* very larg blocks will tend to get broken up */
160 /* during each GC cycle. It is likely to result in a */
161 /* larger working set, but lower collection */
162 /* frequencies, and hence fewer instructions executed */
163 /* in the collector. */
164
165GC_API int GC_full_freq; /* Number of partial collections between */
166 /* full collections. Matters only if */
167 /* GC_incremental is set. */
168 /* Full collections are also triggered if */
169 /* the collector detects a substantial */
170 /* increase in the number of in-use heap */
171 /* blocks. Values in the tens are now */
172 /* perfectly reasonable, unlike for */
173 /* earlier GC versions. */
174
175GC_API GC_word GC_non_gc_bytes;
176 /* Bytes not considered candidates for collection. */
177 /* Used only to control scheduling of collections. */
178 /* Updated by GC_malloc_uncollectable and GC_free. */
179 /* Wizards only. */
180
181GC_API int GC_no_dls;
182 /* Don't register dynamic library data segments. */
183 /* Wizards only. Should be used only if the */
184 /* application explicitly registers all roots. */
185 /* In Microsoft Windows environments, this will */
186 /* usually also prevent registration of the */
187 /* main data segment as part of the root set. */
188
189GC_API GC_word GC_free_space_divisor;
190 /* We try to make sure that we allocate at */
191 /* least N/GC_free_space_divisor bytes between */
192 /* collections, where N is the heap size plus */
193 /* a rough estimate of the root set size. */
194 /* Initially, GC_free_space_divisor = 3. */
195 /* Increasing its value will use less space */
196 /* but more collection time. Decreasing it */
197 /* will appreciably decrease collection time */
198 /* at the expense of space. */
199 /* GC_free_space_divisor = 1 will effectively */
200 /* disable collections. */
201
202GC_API GC_word GC_max_retries;
203 /* The maximum number of GCs attempted before */
204 /* reporting out of memory after heap */
205 /* expansion fails. Initially 0. */
206
207
208GC_API char *GC_stackbottom; /* Cool end of user stack. */
209 /* May be set in the client prior to */
210 /* calling any GC_ routines. This */
211 /* avoids some overhead, and */
212 /* potentially some signals that can */
213 /* confuse debuggers. Otherwise the */
214 /* collector attempts to set it */
215 /* automatically. */
216 /* For multithreaded code, this is the */
217 /* cold end of the stack for the */
218 /* primordial thread. */
219
220GC_API int GC_dont_precollect; /* Don't collect as part of */
221 /* initialization. Should be set only */
222 /* if the client wants a chance to */
223 /* manually initialize the root set */
224 /* before the first collection. */
225 /* Interferes with blacklisting. */
226 /* Wizards only. */
227
228GC_API unsigned long GC_time_limit;
229 /* If incremental collection is enabled, */
230 /* We try to terminate collections */
231 /* after this many milliseconds. Not a */
232 /* hard time bound. Setting this to */
233 /* GC_TIME_UNLIMITED will essentially */
234 /* disable incremental collection while */
235 /* leaving generational collection */
236 /* enabled. */
237# define GC_TIME_UNLIMITED 999999
238 /* Setting GC_time_limit to this value */
239 /* will disable the "pause time exceeded"*/
240 /* tests. */
241
242/* Public procedures */
243
244/* Initialize the collector. This is only required when using thread-local
245 * allocation, since unlike the regular allocation routines, GC_local_malloc
246 * is not self-initializing. If you use GC_local_malloc you should arrange
247 * to call this somehow (e.g. from a constructor) before doing any allocation.
248 * For win32 threads, it needs to be called explicitly.
249 */
250GC_API void GC_init GC_PROTO((void));
251
252/*
253 * general purpose allocation routines, with roughly malloc calling conv.
254 * The atomic versions promise that no relevant pointers are contained
255 * in the object. The nonatomic versions guarantee that the new object
256 * is cleared. GC_malloc_stubborn promises that no changes to the object
257 * will occur after GC_end_stubborn_change has been called on the
258 * result of GC_malloc_stubborn. GC_malloc_uncollectable allocates an object
259 * that is scanned for pointers to collectable objects, but is not itself
260 * collectable. The object is scanned even if it does not appear to
261 * be reachable. GC_malloc_uncollectable and GC_free called on the resulting
262 * object implicitly update GC_non_gc_bytes appropriately.
263 *
264 * Note that the GC_malloc_stubborn support is stubbed out by default
265 * starting in 6.0. GC_malloc_stubborn is an alias for GC_malloc unless
266 * the collector is built with STUBBORN_ALLOC defined.
267 */
268GC_API GC_PTR GC_malloc GC_PROTO((size_t size_in_bytes));
269GC_API GC_PTR GC_malloc_atomic GC_PROTO((size_t size_in_bytes));
270GC_API char *GC_strdup GC_PROTO((const char *str));
271GC_API GC_PTR GC_malloc_uncollectable GC_PROTO((size_t size_in_bytes));
272GC_API GC_PTR GC_malloc_stubborn GC_PROTO((size_t size_in_bytes));
273
274/* The following is only defined if the library has been suitably */
275/* compiled: */
276GC_API GC_PTR GC_malloc_atomic_uncollectable GC_PROTO((size_t size_in_bytes));
277
278/* Explicitly deallocate an object. Dangerous if used incorrectly. */
279/* Requires a pointer to the base of an object. */
280/* If the argument is stubborn, it should not be changeable when freed. */
281/* An object should not be enable for finalization when it is */
282/* explicitly deallocated. */
283/* GC_free(0) is a no-op, as required by ANSI C for free. */
284GC_API void GC_free GC_PROTO((GC_PTR object_addr));
285
286/*
287 * Stubborn objects may be changed only if the collector is explicitly informed.
288 * The collector is implicitly informed of coming change when such
289 * an object is first allocated. The following routines inform the
290 * collector that an object will no longer be changed, or that it will
291 * once again be changed. Only nonNIL pointer stores into the object
292 * are considered to be changes. The argument to GC_end_stubborn_change
293 * must be exacly the value returned by GC_malloc_stubborn or passed to
294 * GC_change_stubborn. (In the second case it may be an interior pointer
295 * within 512 bytes of the beginning of the objects.)
296 * There is a performance penalty for allowing more than
297 * one stubborn object to be changed at once, but it is acceptable to
298 * do so. The same applies to dropping stubborn objects that are still
299 * changeable.
300 */
301GC_API void GC_change_stubborn GC_PROTO((GC_PTR));
302GC_API void GC_end_stubborn_change GC_PROTO((GC_PTR));
303
304/* Return a pointer to the base (lowest address) of an object given */
305/* a pointer to a location within the object. */
306/* I.e. map an interior pointer to the corresponding bas pointer. */
307/* Note that with debugging allocation, this returns a pointer to the */
308/* actual base of the object, i.e. the debug information, not to */
309/* the base of the user object. */
310/* Return 0 if displaced_pointer doesn't point to within a valid */
311/* object. */
312/* Note that a deallocated object in the garbage collected heap */
313/* may be considered valid, even if it has been deallocated with */
314/* GC_free. */
315GC_API GC_PTR GC_base GC_PROTO((GC_PTR displaced_pointer));
316
317/* Given a pointer to the base of an object, return its size in bytes. */
318/* The returned size may be slightly larger than what was originally */
319/* requested. */
320GC_API size_t GC_size GC_PROTO((GC_PTR object_addr));
321
322/* For compatibility with C library. This is occasionally faster than */
323/* a malloc followed by a bcopy. But if you rely on that, either here */
324/* or with the standard C library, your code is broken. In my */
325/* opinion, it shouldn't have been invented, but now we're stuck. -HB */
326/* The resulting object has the same kind as the original. */
327/* If the argument is stubborn, the result will have changes enabled. */
328/* It is an error to have changes enabled for the original object. */
329/* Follows ANSI comventions for NULL old_object. */
330GC_API GC_PTR GC_realloc
331 GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes));
332
333/* Explicitly increase the heap size. */
334/* Returns 0 on failure, 1 on success. */
335GC_API int GC_expand_hp GC_PROTO((size_t number_of_bytes));
336
337/* Limit the heap size to n bytes. Useful when you're debugging, */
338/* especially on systems that don't handle running out of memory well. */
339/* n == 0 ==> unbounded. This is the default. */
340GC_API void GC_set_max_heap_size GC_PROTO((GC_word n));
341
342/* Inform the collector that a certain section of statically allocated */
343/* memory contains no pointers to garbage collected memory. Thus it */
344/* need not be scanned. This is sometimes important if the application */
345/* maps large read/write files into the address space, which could be */
346/* mistaken for dynamic library data segments on some systems. */
347GC_API void GC_exclude_static_roots GC_PROTO((GC_PTR start, GC_PTR finish));
348
349/* Clear the set of root segments. Wizards only. */
350GC_API void GC_clear_roots GC_PROTO((void));
351
352/* Add a root segment. Wizards only. */
353GC_API void GC_add_roots GC_PROTO((char * low_address,
354 char * high_address_plus_1));
355
356/* Remove a root segment. Wizards only. */
357GC_API void GC_remove_roots GC_PROTO((char * low_address,
358 char * high_address_plus_1));
359
360/* Add a displacement to the set of those considered valid by the */
361/* collector. GC_register_displacement(n) means that if p was returned */
362/* by GC_malloc, then (char *)p + n will be considered to be a valid */
363/* pointer to p. N must be small and less than the size of p. */
364/* (All pointers to the interior of objects from the stack are */
365/* considered valid in any case. This applies to heap objects and */
366/* static data.) */
367/* Preferably, this should be called before any other GC procedures. */
368/* Calling it later adds to the probability of excess memory */
369/* retention. */
370/* This is a no-op if the collector has recognition of */
371/* arbitrary interior pointers enabled, which is now the default. */
372GC_API void GC_register_displacement GC_PROTO((GC_word n));
373
374/* The following version should be used if any debugging allocation is */
375/* being done. */
376GC_API void GC_debug_register_displacement GC_PROTO((GC_word n));
377
378/* Explicitly trigger a full, world-stop collection. */
379GC_API void GC_gcollect GC_PROTO((void));
380
381/* Trigger a full world-stopped collection. Abort the collection if */
382/* and when stop_func returns a nonzero value. Stop_func will be */
383/* called frequently, and should be reasonably fast. This works even */
384/* if virtual dirty bits, and hence incremental collection is not */
385/* available for this architecture. Collections can be aborted faster */
386/* than normal pause times for incremental collection. However, */
387/* aborted collections do no useful work; the next collection needs */
388/* to start from the beginning. */
389/* Return 0 if the collection was aborted, 1 if it succeeded. */
390typedef int (* GC_stop_func) GC_PROTO((void));
391GC_API int GC_try_to_collect GC_PROTO((GC_stop_func stop_func));
392
393/* Return the number of bytes in the heap. Excludes collector private */
394/* data structures. Includes empty blocks and fragmentation loss. */
395/* Includes some pages that were allocated but never written. */
396GC_API size_t GC_get_heap_size GC_PROTO((void));
397
398/* Return a lower bound on the number of free bytes in the heap. */
399GC_API size_t GC_get_free_bytes GC_PROTO((void));
400
401/* Return the number of bytes allocated since the last collection. */
402GC_API size_t GC_get_bytes_since_gc GC_PROTO((void));
403
404/* Return the total number of bytes allocated in this process. */
405/* Never decreases, except due to wrapping. */
406GC_API size_t GC_get_total_bytes GC_PROTO((void));
407
408/* Disable garbage collection. Even GC_gcollect calls will be */
409/* ineffective. */
410GC_API void GC_disable GC_PROTO((void));
411
412/* Reenable garbage collection. GC_disable() and GC_enable() calls */
413/* nest. Garbage collection is enabled if the number of calls to both */
414/* both functions is equal. */
415GC_API void GC_enable GC_PROTO((void));
416
417/* Enable incremental/generational collection. */
418/* Not advisable unless dirty bits are */
419/* available or most heap objects are */
420/* pointerfree(atomic) or immutable. */
421/* Don't use in leak finding mode. */
422/* Ignored if GC_dont_gc is true. */
423/* Only the generational piece of this is */
424/* functional if GC_parallel is TRUE */
425/* or if GC_time_limit is GC_TIME_UNLIMITED. */
426/* Causes GC_local_gcj_malloc() to revert to */
427/* locked allocation. Must be called */
428/* before any GC_local_gcj_malloc() calls. */
429GC_API void GC_enable_incremental GC_PROTO((void));
430
431/* Does incremental mode write-protect pages? Returns zero or */
432/* more of the following, or'ed together: */
433#define GC_PROTECTS_POINTER_HEAP 1 /* May protect non-atomic objs. */
434#define GC_PROTECTS_PTRFREE_HEAP 2
435#define GC_PROTECTS_STATIC_DATA 4 /* Curently never. */
436#define GC_PROTECTS_STACK 8 /* Probably impractical. */
437
438#define GC_PROTECTS_NONE 0
439GC_API int GC_incremental_protection_needs GC_PROTO((void));
440
441/* Perform some garbage collection work, if appropriate. */
442/* Return 0 if there is no more work to be done. */
443/* Typically performs an amount of work corresponding roughly */
444/* to marking from one page. May do more work if further */
445/* progress requires it, e.g. if incremental collection is */
446/* disabled. It is reasonable to call this in a wait loop */
447/* until it returns 0. */
448GC_API int GC_collect_a_little GC_PROTO((void));
449
450/* Allocate an object of size lb bytes. The client guarantees that */
451/* as long as the object is live, it will be referenced by a pointer */
452/* that points to somewhere within the first 256 bytes of the object. */
453/* (This should normally be declared volatile to prevent the compiler */
454/* from invalidating this assertion.) This routine is only useful */
455/* if a large array is being allocated. It reduces the chance of */
456/* accidentally retaining such an array as a result of scanning an */
457/* integer that happens to be an address inside the array. (Actually, */
458/* it reduces the chance of the allocator not finding space for such */
459/* an array, since it will try hard to avoid introducing such a false */
460/* reference.) On a SunOS 4.X or MS Windows system this is recommended */
461/* for arrays likely to be larger than 100K or so. For other systems, */
462/* or if the collector is not configured to recognize all interior */
463/* pointers, the threshold is normally much higher. */
464GC_API GC_PTR GC_malloc_ignore_off_page GC_PROTO((size_t lb));
465GC_API GC_PTR GC_malloc_atomic_ignore_off_page GC_PROTO((size_t lb));
466
467#if defined(__sgi) && !defined(__GNUC__) && _COMPILER_VERSION >= 720
468# define GC_ADD_CALLER
469# define GC_RETURN_ADDR (GC_word)__return_address
470#endif
471
472#if defined(__linux__) || defined(__GLIBC__)
473# include <features.h>
474# if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1 || __GLIBC__ > 2) \
475 && !defined(__ia64__)
476# ifndef GC_HAVE_BUILTIN_BACKTRACE
477# define GC_HAVE_BUILTIN_BACKTRACE
478# endif
479# endif
480# if defined(__i386__) || defined(__x86_64__)
481# define GC_CAN_SAVE_CALL_STACKS
482# endif
483#endif
484
485#if defined(GC_HAVE_BUILTIN_BACKTRACE) && !defined(GC_CAN_SAVE_CALL_STACKS)
486# define GC_CAN_SAVE_CALL_STACKS
487#endif
488
489#if defined(__sparc__)
490# define GC_CAN_SAVE_CALL_STACKS
491#endif
492
493/* If we're on an a platform on which we can't save call stacks, but */
494/* gcc is normally used, we go ahead and define GC_ADD_CALLER. */
495/* We make this decision independent of whether gcc is actually being */
496/* used, in order to keep the interface consistent, and allow mixing */
497/* of compilers. */
498/* This may also be desirable if it is possible but expensive to */
499/* retrieve the call chain. */
500#if (defined(__linux__) || defined(__NetBSD__) || defined(__OpenBSD__) \
501 || defined(__FreeBSD__) || defined(__DragonFly__)) & !defined(GC_CAN_SAVE_CALL_STACKS)
502# define GC_ADD_CALLER
503# if __GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95)
504 /* gcc knows how to retrieve return address, but we don't know */
505 /* how to generate call stacks. */
506# define GC_RETURN_ADDR (GC_word)__builtin_return_address(0)
507# else
508 /* Just pass 0 for gcc compatibility. */
509# define GC_RETURN_ADDR 0
510# endif
511#endif
512
513#ifdef GC_ADD_CALLER
514# define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__
515# define GC_EXTRA_PARAMS GC_word ra, GC_CONST char * s, int i
516#else
517# define GC_EXTRAS __FILE__, __LINE__
518# define GC_EXTRA_PARAMS GC_CONST char * s, int i
519#endif
520
521/* Debugging (annotated) allocation. GC_gcollect will check */
522/* objects allocated in this way for overwrites, etc. */
523GC_API GC_PTR GC_debug_malloc
524 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
525GC_API GC_PTR GC_debug_malloc_atomic
526 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
527GC_API char *GC_debug_strdup
528 GC_PROTO((const char *str, GC_EXTRA_PARAMS));
529GC_API GC_PTR GC_debug_malloc_uncollectable
530 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
531GC_API GC_PTR GC_debug_malloc_stubborn
532 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
533GC_API GC_PTR GC_debug_malloc_ignore_off_page
534 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
535GC_API GC_PTR GC_debug_malloc_atomic_ignore_off_page
536 GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
537GC_API void GC_debug_free GC_PROTO((GC_PTR object_addr));
538GC_API GC_PTR GC_debug_realloc
539 GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes,
540 GC_EXTRA_PARAMS));
541GC_API void GC_debug_change_stubborn GC_PROTO((GC_PTR));
542GC_API void GC_debug_end_stubborn_change GC_PROTO((GC_PTR));
543
544/* Routines that allocate objects with debug information (like the */
545/* above), but just fill in dummy file and line number information. */
546/* Thus they can serve as drop-in malloc/realloc replacements. This */
547/* can be useful for two reasons: */
548/* 1) It allows the collector to be built with DBG_HDRS_ALL defined */
549/* even if some allocation calls come from 3rd party libraries */
550/* that can't be recompiled. */
551/* 2) On some platforms, the file and line information is redundant, */
552/* since it can be reconstructed from a stack trace. On such */
553/* platforms it may be more convenient not to recompile, e.g. for */
554/* leak detection. This can be accomplished by instructing the */
555/* linker to replace malloc/realloc with these. */
556GC_API GC_PTR GC_debug_malloc_replacement GC_PROTO((size_t size_in_bytes));
557GC_API GC_PTR GC_debug_realloc_replacement
558 GC_PROTO((GC_PTR object_addr, size_t size_in_bytes));
559
560# ifdef GC_DEBUG
561# define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS)
562# define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS)
563# define GC_STRDUP(s) GC_debug_strdup((s), GC_EXTRAS)
564# define GC_MALLOC_UNCOLLECTABLE(sz) \
565 GC_debug_malloc_uncollectable(sz, GC_EXTRAS)
566# define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
567 GC_debug_malloc_ignore_off_page(sz, GC_EXTRAS)
568# define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
569 GC_debug_malloc_atomic_ignore_off_page(sz, GC_EXTRAS)
570# define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, GC_EXTRAS)
571# define GC_FREE(p) GC_debug_free(p)
572# define GC_REGISTER_FINALIZER(p, f, d, of, od) \
573 GC_debug_register_finalizer(p, f, d, of, od)
574# define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
575 GC_debug_register_finalizer_ignore_self(p, f, d, of, od)
576# define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
577 GC_debug_register_finalizer_no_order(p, f, d, of, od)
578# define GC_MALLOC_STUBBORN(sz) GC_debug_malloc_stubborn(sz, GC_EXTRAS);
579# define GC_CHANGE_STUBBORN(p) GC_debug_change_stubborn(p)
580# define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
581# define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
582 GC_general_register_disappearing_link(link, GC_base(obj))
583# define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
584# else
585# define GC_MALLOC(sz) GC_malloc(sz)
586# define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
587# define GC_STRDUP(s) GC_strdup(s)
588# define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz)
589# define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
590 GC_malloc_ignore_off_page(sz)
591# define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
592 GC_malloc_atomic_ignore_off_page(sz)
593# define GC_REALLOC(old, sz) GC_realloc(old, sz)
594# define GC_FREE(p) GC_free(p)
595# define GC_REGISTER_FINALIZER(p, f, d, of, od) \
596 GC_register_finalizer(p, f, d, of, od)
597# define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
598 GC_register_finalizer_ignore_self(p, f, d, of, od)
599# define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
600 GC_register_finalizer_no_order(p, f, d, of, od)
601# define GC_MALLOC_STUBBORN(sz) GC_malloc_stubborn(sz)
602# define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p)
603# define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
604# define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
605 GC_general_register_disappearing_link(link, obj)
606# define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
607# endif
608/* The following are included because they are often convenient, and */
609/* reduce the chance for a misspecifed size argument. But calls may */
610/* expand to something syntactically incorrect if t is a complicated */
611/* type expression. */
612# define GC_NEW(t) (t *)GC_MALLOC(sizeof (t))
613# define GC_NEW_ATOMIC(t) (t *)GC_MALLOC_ATOMIC(sizeof (t))
614# define GC_NEW_STUBBORN(t) (t *)GC_MALLOC_STUBBORN(sizeof (t))
615# define GC_NEW_UNCOLLECTABLE(t) (t *)GC_MALLOC_UNCOLLECTABLE(sizeof (t))
616
617/* Finalization. Some of these primitives are grossly unsafe. */
618/* The idea is to make them both cheap, and sufficient to build */
619/* a safer layer, closer to Modula-3, Java, or PCedar finalization. */
620/* The interface represents my conclusions from a long discussion */
621/* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes, */
622/* Christian Jacobi, and Russ Atkinson. It's not perfect, and */
623/* probably nobody else agrees with it. Hans-J. Boehm 3/13/92 */
624typedef void (*GC_finalization_proc)
625 GC_PROTO((GC_PTR obj, GC_PTR client_data));
626
627GC_API void GC_register_finalizer
628 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
629 GC_finalization_proc *ofn, GC_PTR *ocd));
630GC_API void GC_debug_register_finalizer
631 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
632 GC_finalization_proc *ofn, GC_PTR *ocd));
633 /* When obj is no longer accessible, invoke */
634 /* (*fn)(obj, cd). If a and b are inaccessible, and */
635 /* a points to b (after disappearing links have been */
636 /* made to disappear), then only a will be */
637 /* finalized. (If this does not create any new */
638 /* pointers to b, then b will be finalized after the */
639 /* next collection.) Any finalizable object that */
640 /* is reachable from itself by following one or more */
641 /* pointers will not be finalized (or collected). */
642 /* Thus cycles involving finalizable objects should */
643 /* be avoided, or broken by disappearing links. */
644 /* All but the last finalizer registered for an object */
645 /* is ignored. */
646 /* Finalization may be removed by passing 0 as fn. */
647 /* Finalizers are implicitly unregistered just before */
648 /* they are invoked. */
649 /* The old finalizer and client data are stored in */
650 /* *ofn and *ocd. */
651 /* Fn is never invoked on an accessible object, */
652 /* provided hidden pointers are converted to real */
653 /* pointers only if the allocation lock is held, and */
654 /* such conversions are not performed by finalization */
655 /* routines. */
656 /* If GC_register_finalizer is aborted as a result of */
657 /* a signal, the object may be left with no */
658 /* finalization, even if neither the old nor new */
659 /* finalizer were NULL. */
660 /* Obj should be the nonNULL starting address of an */
661 /* object allocated by GC_malloc or friends. */
662 /* Note that any garbage collectable object referenced */
663 /* by cd will be considered accessible until the */
664 /* finalizer is invoked. */
665
666/* Another versions of the above follow. It ignores */
667/* self-cycles, i.e. pointers from a finalizable object to */
668/* itself. There is a stylistic argument that this is wrong, */
669/* but it's unavoidable for C++, since the compiler may */
670/* silently introduce these. It's also benign in that specific */
671/* case. And it helps if finalizable objects are split to */
672/* avoid cycles. */
673/* Note that cd will still be viewed as accessible, even if it */
674/* refers to the object itself. */
675GC_API void GC_register_finalizer_ignore_self
676 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
677 GC_finalization_proc *ofn, GC_PTR *ocd));
678GC_API void GC_debug_register_finalizer_ignore_self
679 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
680 GC_finalization_proc *ofn, GC_PTR *ocd));
681
682/* Another version of the above. It ignores all cycles. */
683/* It should probably only be used by Java implementations. */
684/* Note that cd will still be viewed as accessible, even if it */
685/* refers to the object itself. */
686GC_API void GC_register_finalizer_no_order
687 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
688 GC_finalization_proc *ofn, GC_PTR *ocd));
689GC_API void GC_debug_register_finalizer_no_order
690 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
691 GC_finalization_proc *ofn, GC_PTR *ocd));
692
693
694/* The following routine may be used to break cycles between */
695/* finalizable objects, thus causing cyclic finalizable */
696/* objects to be finalized in the correct order. Standard */
697/* use involves calling GC_register_disappearing_link(&p), */
698/* where p is a pointer that is not followed by finalization */
699/* code, and should not be considered in determining */
700/* finalization order. */
701GC_API int GC_register_disappearing_link GC_PROTO((GC_PTR * /* link */));
702 /* Link should point to a field of a heap allocated */
703 /* object obj. *link will be cleared when obj is */
704 /* found to be inaccessible. This happens BEFORE any */
705 /* finalization code is invoked, and BEFORE any */
706 /* decisions about finalization order are made. */
707 /* This is useful in telling the finalizer that */
708 /* some pointers are not essential for proper */
709 /* finalization. This may avoid finalization cycles. */
710 /* Note that obj may be resurrected by another */
711 /* finalizer, and thus the clearing of *link may */
712 /* be visible to non-finalization code. */
713 /* There's an argument that an arbitrary action should */
714 /* be allowed here, instead of just clearing a pointer. */
715 /* But this causes problems if that action alters, or */
716 /* examines connectivity. */
717 /* Returns 1 if link was already registered, 0 */
718 /* otherwise. */
719 /* Only exists for backward compatibility. See below: */
720
721GC_API int GC_general_register_disappearing_link
722 GC_PROTO((GC_PTR * /* link */, GC_PTR obj));
723 /* A slight generalization of the above. *link is */
724 /* cleared when obj first becomes inaccessible. This */
725 /* can be used to implement weak pointers easily and */
726 /* safely. Typically link will point to a location */
727 /* holding a disguised pointer to obj. (A pointer */
728 /* inside an "atomic" object is effectively */
729 /* disguised.) In this way soft */
730 /* pointers are broken before any object */
731 /* reachable from them are finalized. Each link */
732 /* May be registered only once, i.e. with one obj */
733 /* value. This was added after a long email discussion */
734 /* with John Ellis. */
735 /* Obj must be a pointer to the first word of an object */
736 /* we allocated. It is unsafe to explicitly deallocate */
737 /* the object containing link. Explicitly deallocating */
738 /* obj may or may not cause link to eventually be */
739 /* cleared. */
740GC_API int GC_unregister_disappearing_link GC_PROTO((GC_PTR * /* link */));
741 /* Returns 0 if link was not actually registered. */
742 /* Undoes a registration by either of the above two */
743 /* routines. */
744
745/* Returns !=0 if GC_invoke_finalizers has something to do. */
746GC_API int GC_should_invoke_finalizers GC_PROTO((void));
747
748GC_API int GC_invoke_finalizers GC_PROTO((void));
749 /* Run finalizers for all objects that are ready to */
750 /* be finalized. Return the number of finalizers */
751 /* that were run. Normally this is also called */
752 /* implicitly during some allocations. If */
753 /* GC_finalize_on_demand is nonzero, it must be called */
754 /* explicitly. */
755
756/* GC_set_warn_proc can be used to redirect or filter warning messages. */
757/* p may not be a NULL pointer. */
758typedef void (*GC_warn_proc) GC_PROTO((char *msg, GC_word arg));
759GC_API GC_warn_proc GC_set_warn_proc GC_PROTO((GC_warn_proc p));
760 /* Returns old warning procedure. */
761
762GC_API GC_word GC_set_free_space_divisor GC_PROTO((GC_word value));
763 /* Set free_space_divisor. See above for definition. */
764 /* Returns old value. */
765
766/* The following is intended to be used by a higher level */
767/* (e.g. Java-like) finalization facility. It is expected */
768/* that finalization code will arrange for hidden pointers to */
769/* disappear. Otherwise objects can be accessed after they */
770/* have been collected. */
771/* Note that putting pointers in atomic objects or in */
772/* nonpointer slots of "typed" objects is equivalent to */
773/* disguising them in this way, and may have other advantages. */
774# if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
775 typedef GC_word GC_hidden_pointer;
776# define HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
777# define REVEAL_POINTER(p) ((GC_PTR)(HIDE_POINTER(p)))
778 /* Converting a hidden pointer to a real pointer requires verifying */
779 /* that the object still exists. This involves acquiring the */
780 /* allocator lock to avoid a race with the collector. */
781# endif /* I_HIDE_POINTERS */
782
783typedef GC_PTR (*GC_fn_type) GC_PROTO((GC_PTR client_data));
784GC_API GC_PTR GC_call_with_alloc_lock
785 GC_PROTO((GC_fn_type fn, GC_PTR client_data));
786
787/* The following routines are primarily intended for use with a */
788/* preprocessor which inserts calls to check C pointer arithmetic. */
789/* They indicate failure by invoking the corresponding _print_proc. */
790
791/* Check that p and q point to the same object. */
792/* Fail conspicuously if they don't. */
793/* Returns the first argument. */
794/* Succeeds if neither p nor q points to the heap. */
795/* May succeed if both p and q point to between heap objects. */
796GC_API GC_PTR GC_same_obj GC_PROTO((GC_PTR p, GC_PTR q));
797
798/* Checked pointer pre- and post- increment operations. Note that */
799/* the second argument is in units of bytes, not multiples of the */
800/* object size. This should either be invoked from a macro, or the */
801/* call should be automatically generated. */
802GC_API GC_PTR GC_pre_incr GC_PROTO((GC_PTR *p, size_t how_much));
803GC_API GC_PTR GC_post_incr GC_PROTO((GC_PTR *p, size_t how_much));
804
805/* Check that p is visible */
806/* to the collector as a possibly pointer containing location. */
807/* If it isn't fail conspicuously. */
808/* Returns the argument in all cases. May erroneously succeed */
809/* in hard cases. (This is intended for debugging use with */
810/* untyped allocations. The idea is that it should be possible, though */
811/* slow, to add such a call to all indirect pointer stores.) */
812/* Currently useless for multithreaded worlds. */
813GC_API GC_PTR GC_is_visible GC_PROTO((GC_PTR p));
814
815/* Check that if p is a pointer to a heap page, then it points to */
816/* a valid displacement within a heap object. */
817/* Fail conspicuously if this property does not hold. */
818/* Uninteresting with GC_all_interior_pointers. */
819/* Always returns its argument. */
820GC_API GC_PTR GC_is_valid_displacement GC_PROTO((GC_PTR p));
821
822/* Safer, but slow, pointer addition. Probably useful mainly with */
823/* a preprocessor. Useful only for heap pointers. */
824#ifdef GC_DEBUG
825# define GC_PTR_ADD3(x, n, type_of_result) \
826 ((type_of_result)GC_same_obj((x)+(n), (x)))
827# define GC_PRE_INCR3(x, n, type_of_result) \
828 ((type_of_result)GC_pre_incr(&(x), (n)*sizeof(*x))
829# define GC_POST_INCR2(x, type_of_result) \
830 ((type_of_result)GC_post_incr(&(x), sizeof(*x))
831# ifdef __GNUC__
832# define GC_PTR_ADD(x, n) \
833 GC_PTR_ADD3(x, n, typeof(x))
834# define GC_PRE_INCR(x, n) \
835 GC_PRE_INCR3(x, n, typeof(x))
836# define GC_POST_INCR(x, n) \
837 GC_POST_INCR3(x, typeof(x))
838# else
839 /* We can't do this right without typeof, which ANSI */
840 /* decided was not sufficiently useful. Repeatedly */
841 /* mentioning the arguments seems too dangerous to be */
842 /* useful. So does not casting the result. */
843# define GC_PTR_ADD(x, n) ((x)+(n))
844# endif
845#else /* !GC_DEBUG */
846# define GC_PTR_ADD3(x, n, type_of_result) ((x)+(n))
847# define GC_PTR_ADD(x, n) ((x)+(n))
848# define GC_PRE_INCR3(x, n, type_of_result) ((x) += (n))
849# define GC_PRE_INCR(x, n) ((x) += (n))
850# define GC_POST_INCR2(x, n, type_of_result) ((x)++)
851# define GC_POST_INCR(x, n) ((x)++)
852#endif
853
854/* Safer assignment of a pointer to a nonstack location. */
855#ifdef GC_DEBUG
856# if defined(__STDC__) || defined(_AIX)
857# define GC_PTR_STORE(p, q) \
858 (*(void **)GC_is_visible(p) = GC_is_valid_displacement(q))
859# else
860# define GC_PTR_STORE(p, q) \
861 (*(char **)GC_is_visible(p) = GC_is_valid_displacement(q))
862# endif
863#else /* !GC_DEBUG */
864# define GC_PTR_STORE(p, q) *((p) = (q))
865#endif
866
867/* Functions called to report pointer checking errors */
868GC_API void (*GC_same_obj_print_proc) GC_PROTO((GC_PTR p, GC_PTR q));
869
870GC_API void (*GC_is_valid_displacement_print_proc)
871 GC_PROTO((GC_PTR p));
872
873GC_API void (*GC_is_visible_print_proc)
874 GC_PROTO((GC_PTR p));
875
876
877/* For pthread support, we generally need to intercept a number of */
878/* thread library calls. We do that here by macro defining them. */
879
880#if !defined(GC_USE_LD_WRAP) && \
881 (defined(GC_PTHREADS) || defined(GC_SOLARIS_THREADS))
882# include "gc_pthread_redirects.h"
883#endif
884
885# if defined(PCR) || defined(GC_SOLARIS_THREADS) || \
886 defined(GC_PTHREADS) || defined(GC_WIN32_THREADS)
887 /* Any flavor of threads except SRC_M3. */
888/* This returns a list of objects, linked through their first */
889/* word. Its use can greatly reduce lock contention problems, since */
890/* the allocation lock can be acquired and released many fewer times. */
891/* lb must be large enough to hold the pointer field. */
892/* It is used internally by gc_local_alloc.h, which provides a simpler */
893/* programming interface on Linux. */
894GC_PTR GC_malloc_many(size_t lb);
895#define GC_NEXT(p) (*(GC_PTR *)(p)) /* Retrieve the next element */
896 /* in returned list. */
897extern void GC_thr_init GC_PROTO((void));/* Needed for Solaris/X86 */
898
899#endif /* THREADS && !SRC_M3 */
900
901#if defined(GC_WIN32_THREADS) && !defined(__CYGWIN32__) && !defined(__CYGWIN__)
902# include <windows.h>
903
904 /*
905 * All threads must be created using GC_CreateThread, so that they will be
906 * recorded in the thread table. For backwards compatibility, this is not
907 * technically true if the GC is built as a dynamic library, since it can
908 * and does then use DllMain to keep track of thread creations. But new code
909 * should be built to call GC_CreateThread.
910 */
911 GC_API HANDLE WINAPI GC_CreateThread(
912 LPSECURITY_ATTRIBUTES lpThreadAttributes,
913 DWORD dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress,
914 LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId );
915
916# if defined(_WIN32_WCE)
917 /*
918 * win32_threads.c implements the real WinMain, which will start a new thread
919 * to call GC_WinMain after initializing the garbage collector.
920 */
921 int WINAPI GC_WinMain(
922 HINSTANCE hInstance,
923 HINSTANCE hPrevInstance,
924 LPWSTR lpCmdLine,
925 int nCmdShow );
926
927# ifndef GC_BUILD
928# define WinMain GC_WinMain
929# define CreateThread GC_CreateThread
930# endif
931# endif /* defined(_WIN32_WCE) */
932
933#endif /* defined(GC_WIN32_THREADS) && !cygwin */
934
935 /*
936 * Fully portable code should call GC_INIT() from the main program
937 * before making any other GC_ calls. On most platforms this is a
938 * no-op and the collector self-initializes. But a number of platforms
939 * make that too hard.
940 */
941#if (defined(sparc) || defined(__sparc)) && defined(sun)
942 /*
943 * If you are planning on putting
944 * the collector in a SunOS 5 dynamic library, you need to call GC_INIT()
945 * from the statically loaded program section.
946 * This circumvents a Solaris 2.X (X<=4) linker bug.
947 */
948 extern int _end[], _etext[];
949# ifdef __cplusplus
950 extern "C" void GC_noop1(GC_word);
951# else
952 void GC_noop1();
953# endif /* !__cplusplus */
954# define GC_INIT() { GC_noop1((GC_word)_end); \
955 GC_noop1((GC_word)_etext); }
956#else
957# if defined(__CYGWIN32__) || defined (_AIX)
958 /*
959 * Similarly gnu-win32 DLLs need explicit initialization from
960 * the main program, as does AIX.
961 */
962# ifdef __CYGWIN32__
963 extern int _data_start__[];
964 extern int _data_end__[];
965 extern int _bss_start__[];
966 extern int _bss_end__[];
967# define GC_MAX(x,y) ((x) > (y) ? (x) : (y))
968# define GC_MIN(x,y) ((x) < (y) ? (x) : (y))
969# define GC_DATASTART ((GC_PTR) GC_MIN(_data_start__, _bss_start__))
970# define GC_DATAEND ((GC_PTR) GC_MAX(_data_end__, _bss_end__))
971# ifdef GC_DLL
972# define GC_INIT() { GC_add_roots(GC_DATASTART, GC_DATAEND); }
973# else
974# define GC_INIT()
975# endif
976# endif
977# if defined(_AIX)
978 extern int _data[], _end[];
979# define GC_DATASTART ((GC_PTR)((ulong)_data))
980# define GC_DATAEND ((GC_PTR)((ulong)_end))
981# define GC_INIT() { GC_add_roots(GC_DATASTART, GC_DATAEND); }
982# endif
983# else
984# if defined(__APPLE__) && defined(__MACH__) || defined(GC_WIN32_THREADS)
985# define GC_INIT() { GC_init(); }
986# else
987# define GC_INIT()
988# endif /* !__MACH && !GC_WIN32_THREADS */
989# endif /* !AIX && !cygwin */
990#endif /* !sparc */
991
992#if !defined(_WIN32_WCE) \
993 && ((defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \
994 || defined(_WIN32) && !defined(__CYGWIN32__) && !defined(__CYGWIN__))
995 /* win32S may not free all resources on process exit. */
996 /* This explicitly deallocates the heap. */
997 GC_API void GC_win32_free_heap ();
998#endif
999
1000#if ( defined(_AMIGA) && !defined(GC_AMIGA_MAKINGLIB) )
1001 /* Allocation really goes through GC_amiga_allocwrapper_do */
1002# include "gc_amiga_redirects.h"
1003#endif
1004
1005#if defined(GC_REDIRECT_TO_LOCAL) && !defined(GC_LOCAL_ALLOC_H)
1006# include "gc_local_alloc.h"
1007#endif
1008
1009#ifdef __cplusplus
1010 } /* end of extern "C" */
1011#endif
1012
1013#endif /* _GC_H */
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