Annotation of OpenXM_contrib/gc/gc.h, Revision 1.1.1.1
1.1 maekawa 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 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: * Note that this defines a large number of tuning hooks, which can
18: * safely be ignored in nearly all cases. For normal use it suffices
19: * to call only GC_MALLOC and perhaps GC_REALLOC.
20: * For better performance, also look at GC_MALLOC_ATOMIC, and
21: * GC_enable_incremental. If you need an action to be performed
22: * immediately before an object is collected, look at GC_register_finalizer.
23: * If you are using Solaris threads, look at the end of this file.
24: * Everything else is best ignored unless you encounter performance
25: * problems.
26: */
27:
28: #ifndef _GC_H
29:
30: # define _GC_H
31: # define __GC
32: # include <stddef.h>
33:
34: #if defined(__CYGWIN32__) && defined(GC_USE_DLL)
35: #include "libgc_globals.h"
36: #endif
37:
38: #if defined(_MSC_VER) && defined(_DLL)
39: # ifdef GC_BUILD
40: # define GC_API __declspec(dllexport)
41: # else
42: # define GC_API __declspec(dllimport)
43: # endif
44: #endif
45:
46: #if defined(__WATCOMC__) && defined(GC_DLL)
47: # ifdef GC_BUILD
48: # define GC_API extern __declspec(dllexport)
49: # else
50: # define GC_API extern __declspec(dllimport)
51: # endif
52: #endif
53:
54: #ifndef GC_API
55: #define GC_API extern
56: #endif
57:
58: # if defined(__STDC__) || defined(__cplusplus)
59: # define GC_PROTO(args) args
60: typedef void * GC_PTR;
61: # else
62: # define GC_PROTO(args) ()
63: typedef char * GC_PTR;
64: # endif
65:
66: # ifdef __cplusplus
67: extern "C" {
68: # endif
69:
70:
71: /* Define word and signed_word to be unsigned and signed types of the */
72: /* size as char * or void *. There seems to be no way to do this */
73: /* even semi-portably. The following is probably no better/worse */
74: /* than almost anything else. */
75: /* The ANSI standard suggests that size_t and ptr_diff_t might be */
76: /* better choices. But those appear to have incorrect definitions */
77: /* on may systems. Notably "typedef int size_t" seems to be both */
78: /* frequent and WRONG. */
79: typedef unsigned long GC_word;
80: typedef long GC_signed_word;
81:
82: /* Public read-only variables */
83:
84: GC_API GC_word GC_gc_no;/* Counter incremented per collection. */
85: /* Includes empty GCs at startup. */
86:
87:
88: /* Public R/W variables */
89:
90: GC_API GC_PTR (*GC_oom_fn) GC_PROTO((size_t bytes_requested));
91: /* When there is insufficient memory to satisfy */
92: /* an allocation request, we return */
93: /* (*GC_oom_fn)(). By default this just */
94: /* returns 0. */
95: /* If it returns, it must return 0 or a valid */
96: /* pointer to a previously allocated heap */
97: /* object. */
98:
99: GC_API int GC_quiet; /* Disable statistics output. Only matters if */
100: /* collector has been compiled with statistics */
101: /* enabled. This involves a performance cost, */
102: /* and is thus not the default. */
103:
104: GC_API int GC_dont_gc; /* Dont collect unless explicitly requested, e.g. */
105: /* because it's not safe. */
106:
107: GC_API int GC_dont_expand;
108: /* Dont expand heap unless explicitly requested */
109: /* or forced to. */
110:
111: GC_API int GC_full_freq; /* Number of partial collections between */
112: /* full collections. Matters only if */
113: /* GC_incremental is set. */
114:
115: GC_API GC_word GC_non_gc_bytes;
116: /* Bytes not considered candidates for collection. */
117: /* Used only to control scheduling of collections. */
118:
119: GC_API GC_word GC_free_space_divisor;
120: /* We try to make sure that we allocate at */
121: /* least N/GC_free_space_divisor bytes between */
122: /* collections, where N is the heap size plus */
123: /* a rough estimate of the root set size. */
124: /* Initially, GC_free_space_divisor = 4. */
125: /* Increasing its value will use less space */
126: /* but more collection time. Decreasing it */
127: /* will appreciably decrease collection time */
128: /* at the expense of space. */
129: /* GC_free_space_divisor = 1 will effectively */
130: /* disable collections. */
131:
132: GC_API GC_word GC_max_retries;
133: /* The maximum number of GCs attempted before */
134: /* reporting out of memory after heap */
135: /* expansion fails. Initially 0. */
136:
137:
138: GC_API char *GC_stackbottom; /* Cool end of user stack. */
139: /* May be set in the client prior to */
140: /* calling any GC_ routines. This */
141: /* avoids some overhead, and */
142: /* potentially some signals that can */
143: /* confuse debuggers. Otherwise the */
144: /* collector attempts to set it */
145: /* automatically. */
146: /* For multithreaded code, this is the */
147: /* cold end of the stack for the */
148: /* primordial thread. */
149:
150: /* Public procedures */
151: /*
152: * general purpose allocation routines, with roughly malloc calling conv.
153: * The atomic versions promise that no relevant pointers are contained
154: * in the object. The nonatomic versions guarantee that the new object
155: * is cleared. GC_malloc_stubborn promises that no changes to the object
156: * will occur after GC_end_stubborn_change has been called on the
157: * result of GC_malloc_stubborn. GC_malloc_uncollectable allocates an object
158: * that is scanned for pointers to collectable objects, but is not itself
159: * collectable. GC_malloc_uncollectable and GC_free called on the resulting
160: * object implicitly update GC_non_gc_bytes appropriately.
161: */
162: GC_API GC_PTR GC_malloc GC_PROTO((size_t size_in_bytes));
163: GC_API GC_PTR GC_malloc_atomic GC_PROTO((size_t size_in_bytes));
164: GC_API GC_PTR GC_malloc_uncollectable GC_PROTO((size_t size_in_bytes));
165: GC_API GC_PTR GC_malloc_stubborn GC_PROTO((size_t size_in_bytes));
166:
167: /* The following is only defined if the library has been suitably */
168: /* compiled: */
169: GC_API GC_PTR GC_malloc_atomic_uncollectable GC_PROTO((size_t size_in_bytes));
170:
171: /* Explicitly deallocate an object. Dangerous if used incorrectly. */
172: /* Requires a pointer to the base of an object. */
173: /* If the argument is stubborn, it should not be changeable when freed. */
174: /* An object should not be enable for finalization when it is */
175: /* explicitly deallocated. */
176: /* GC_free(0) is a no-op, as required by ANSI C for free. */
177: GC_API void GC_free GC_PROTO((GC_PTR object_addr));
178:
179: /*
180: * Stubborn objects may be changed only if the collector is explicitly informed.
181: * The collector is implicitly informed of coming change when such
182: * an object is first allocated. The following routines inform the
183: * collector that an object will no longer be changed, or that it will
184: * once again be changed. Only nonNIL pointer stores into the object
185: * are considered to be changes. The argument to GC_end_stubborn_change
186: * must be exacly the value returned by GC_malloc_stubborn or passed to
187: * GC_change_stubborn. (In the second case it may be an interior pointer
188: * within 512 bytes of the beginning of the objects.)
189: * There is a performance penalty for allowing more than
190: * one stubborn object to be changed at once, but it is acceptable to
191: * do so. The same applies to dropping stubborn objects that are still
192: * changeable.
193: */
194: GC_API void GC_change_stubborn GC_PROTO((GC_PTR));
195: GC_API void GC_end_stubborn_change GC_PROTO((GC_PTR));
196:
197: /* Return a pointer to the base (lowest address) of an object given */
198: /* a pointer to a location within the object. */
199: /* Return 0 if displaced_pointer doesn't point to within a valid */
200: /* object. */
201: GC_API GC_PTR GC_base GC_PROTO((GC_PTR displaced_pointer));
202:
203: /* Given a pointer to the base of an object, return its size in bytes. */
204: /* The returned size may be slightly larger than what was originally */
205: /* requested. */
206: GC_API size_t GC_size GC_PROTO((GC_PTR object_addr));
207:
208: /* For compatibility with C library. This is occasionally faster than */
209: /* a malloc followed by a bcopy. But if you rely on that, either here */
210: /* or with the standard C library, your code is broken. In my */
211: /* opinion, it shouldn't have been invented, but now we're stuck. -HB */
212: /* The resulting object has the same kind as the original. */
213: /* If the argument is stubborn, the result will have changes enabled. */
214: /* It is an error to have changes enabled for the original object. */
215: /* Follows ANSI comventions for NULL old_object. */
216: GC_API GC_PTR GC_realloc
217: GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes));
218:
219: /* Explicitly increase the heap size. */
220: /* Returns 0 on failure, 1 on success. */
221: GC_API int GC_expand_hp GC_PROTO((size_t number_of_bytes));
222:
223: /* Limit the heap size to n bytes. Useful when you're debugging, */
224: /* especially on systems that don't handle running out of memory well. */
225: /* n == 0 ==> unbounded. This is the default. */
226: GC_API void GC_set_max_heap_size GC_PROTO((GC_word n));
227:
228: /* Inform the collector that a certain section of statically allocated */
229: /* memory contains no pointers to garbage collected memory. Thus it */
230: /* need not be scanned. This is sometimes important if the application */
231: /* maps large read/write files into the address space, which could be */
232: /* mistaken for dynamic library data segments on some systems. */
233: GC_API void GC_exclude_static_roots GC_PROTO((GC_PTR start, GC_PTR finish));
234:
235: /* Clear the set of root segments. Wizards only. */
236: GC_API void GC_clear_roots GC_PROTO((void));
237:
238: /* Add a root segment. Wizards only. */
239: GC_API void GC_add_roots GC_PROTO((char * low_address,
240: char * high_address_plus_1));
241:
242: /* Add a displacement to the set of those considered valid by the */
243: /* collector. GC_register_displacement(n) means that if p was returned */
244: /* by GC_malloc, then (char *)p + n will be considered to be a valid */
245: /* pointer to n. N must be small and less than the size of p. */
246: /* (All pointers to the interior of objects from the stack are */
247: /* considered valid in any case. This applies to heap objects and */
248: /* static data.) */
249: /* Preferably, this should be called before any other GC procedures. */
250: /* Calling it later adds to the probability of excess memory */
251: /* retention. */
252: /* This is a no-op if the collector was compiled with recognition of */
253: /* arbitrary interior pointers enabled, which is now the default. */
254: GC_API void GC_register_displacement GC_PROTO((GC_word n));
255:
256: /* The following version should be used if any debugging allocation is */
257: /* being done. */
258: GC_API void GC_debug_register_displacement GC_PROTO((GC_word n));
259:
260: /* Explicitly trigger a full, world-stop collection. */
261: GC_API void GC_gcollect GC_PROTO((void));
262:
263: /* Trigger a full world-stopped collection. Abort the collection if */
264: /* and when stop_func returns a nonzero value. Stop_func will be */
265: /* called frequently, and should be reasonably fast. This works even */
266: /* if virtual dirty bits, and hence incremental collection is not */
267: /* available for this architecture. Collections can be aborted faster */
268: /* than normal pause times for incremental collection. However, */
269: /* aborted collections do no useful work; the next collection needs */
270: /* to start from the beginning. */
271: /* Return 0 if the collection was aborted, 1 if it succeeded. */
272: typedef int (* GC_stop_func) GC_PROTO((void));
273: GC_API int GC_try_to_collect GC_PROTO((GC_stop_func stop_func));
274:
275: /* Return the number of bytes in the heap. Excludes collector private */
276: /* data structures. Includes empty blocks and fragmentation loss. */
277: /* Includes some pages that were allocated but never written. */
278: GC_API size_t GC_get_heap_size GC_PROTO((void));
279:
280: /* Return the number of bytes allocated since the last collection. */
281: GC_API size_t GC_get_bytes_since_gc GC_PROTO((void));
282:
283: /* Enable incremental/generational collection. */
284: /* Not advisable unless dirty bits are */
285: /* available or most heap objects are */
286: /* pointerfree(atomic) or immutable. */
287: /* Don't use in leak finding mode. */
288: /* Ignored if GC_dont_gc is true. */
289: GC_API void GC_enable_incremental GC_PROTO((void));
290:
291: /* Perform some garbage collection work, if appropriate. */
292: /* Return 0 if there is no more work to be done. */
293: /* Typically performs an amount of work corresponding roughly */
294: /* to marking from one page. May do more work if further */
295: /* progress requires it, e.g. if incremental collection is */
296: /* disabled. It is reasonable to call this in a wait loop */
297: /* until it returns 0. */
298: GC_API int GC_collect_a_little GC_PROTO((void));
299:
300: /* Allocate an object of size lb bytes. The client guarantees that */
301: /* as long as the object is live, it will be referenced by a pointer */
302: /* that points to somewhere within the first 256 bytes of the object. */
303: /* (This should normally be declared volatile to prevent the compiler */
304: /* from invalidating this assertion.) This routine is only useful */
305: /* if a large array is being allocated. It reduces the chance of */
306: /* accidentally retaining such an array as a result of scanning an */
307: /* integer that happens to be an address inside the array. (Actually, */
308: /* it reduces the chance of the allocator not finding space for such */
309: /* an array, since it will try hard to avoid introducing such a false */
310: /* reference.) On a SunOS 4.X or MS Windows system this is recommended */
311: /* for arrays likely to be larger than 100K or so. For other systems, */
312: /* or if the collector is not configured to recognize all interior */
313: /* pointers, the threshold is normally much higher. */
314: GC_API GC_PTR GC_malloc_ignore_off_page GC_PROTO((size_t lb));
315: GC_API GC_PTR GC_malloc_atomic_ignore_off_page GC_PROTO((size_t lb));
316:
317: #if defined(__sgi) && !defined(__GNUC__) && _COMPILER_VERSION >= 720
318: # define GC_ADD_CALLER
319: # define GC_RETURN_ADDR (GC_word)__return_address
320: #endif
321:
322: #ifdef GC_ADD_CALLER
323: # define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__
324: # define GC_EXTRA_PARAMS GC_word ra, char * descr_string, int descr_int
325: #else
326: # define GC_EXTRAS __FILE__, __LINE__
327: # define GC_EXTRA_PARAMS char * descr_string, int descr_int
328: #endif
329:
330: /* Debugging (annotated) allocation. GC_gcollect will check */
331: /* objects allocated in this way for overwrites, etc. */
332: GC_API GC_PTR GC_debug_malloc
333: GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
334: GC_API GC_PTR GC_debug_malloc_atomic
335: GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
336: GC_API GC_PTR GC_debug_malloc_uncollectable
337: GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
338: GC_API GC_PTR GC_debug_malloc_stubborn
339: GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
340: GC_API void GC_debug_free GC_PROTO((GC_PTR object_addr));
341: GC_API GC_PTR GC_debug_realloc
342: GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes,
343: GC_EXTRA_PARAMS));
344:
345: GC_API void GC_debug_change_stubborn GC_PROTO((GC_PTR));
346: GC_API void GC_debug_end_stubborn_change GC_PROTO((GC_PTR));
347: # ifdef GC_DEBUG
348: # define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS)
349: # define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS)
350: # define GC_MALLOC_UNCOLLECTABLE(sz) GC_debug_malloc_uncollectable(sz, \
351: GC_EXTRAS)
352: # define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, GC_EXTRAS)
353: # define GC_FREE(p) GC_debug_free(p)
354: # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
355: GC_debug_register_finalizer(p, f, d, of, od)
356: # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
357: GC_debug_register_finalizer_ignore_self(p, f, d, of, od)
358: # define GC_MALLOC_STUBBORN(sz) GC_debug_malloc_stubborn(sz, GC_EXTRAS);
359: # define GC_CHANGE_STUBBORN(p) GC_debug_change_stubborn(p)
360: # define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
361: # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
362: GC_general_register_disappearing_link(link, GC_base(obj))
363: # define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
364: # else
365: # define GC_MALLOC(sz) GC_malloc(sz)
366: # define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
367: # define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz)
368: # define GC_REALLOC(old, sz) GC_realloc(old, sz)
369: # define GC_FREE(p) GC_free(p)
370: # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
371: GC_register_finalizer(p, f, d, of, od)
372: # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
373: GC_register_finalizer_ignore_self(p, f, d, of, od)
374: # define GC_MALLOC_STUBBORN(sz) GC_malloc_stubborn(sz)
375: # define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p)
376: # define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
377: # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
378: GC_general_register_disappearing_link(link, obj)
379: # define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
380: # endif
381: /* The following are included because they are often convenient, and */
382: /* reduce the chance for a misspecifed size argument. But calls may */
383: /* expand to something syntactically incorrect if t is a complicated */
384: /* type expression. */
385: # define GC_NEW(t) (t *)GC_MALLOC(sizeof (t))
386: # define GC_NEW_ATOMIC(t) (t *)GC_MALLOC_ATOMIC(sizeof (t))
387: # define GC_NEW_STUBBORN(t) (t *)GC_MALLOC_STUBBORN(sizeof (t))
388: # define GC_NEW_UNCOLLECTABLE(t) (t *)GC_MALLOC_UNCOLLECTABLE(sizeof (t))
389:
390: /* Finalization. Some of these primitives are grossly unsafe. */
391: /* The idea is to make them both cheap, and sufficient to build */
392: /* a safer layer, closer to PCedar finalization. */
393: /* The interface represents my conclusions from a long discussion */
394: /* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes, */
395: /* Christian Jacobi, and Russ Atkinson. It's not perfect, and */
396: /* probably nobody else agrees with it. Hans-J. Boehm 3/13/92 */
397: typedef void (*GC_finalization_proc)
398: GC_PROTO((GC_PTR obj, GC_PTR client_data));
399:
400: GC_API void GC_register_finalizer
401: GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
402: GC_finalization_proc *ofn, GC_PTR *ocd));
403: GC_API void GC_debug_register_finalizer
404: GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
405: GC_finalization_proc *ofn, GC_PTR *ocd));
406: /* When obj is no longer accessible, invoke */
407: /* (*fn)(obj, cd). If a and b are inaccessible, and */
408: /* a points to b (after disappearing links have been */
409: /* made to disappear), then only a will be */
410: /* finalized. (If this does not create any new */
411: /* pointers to b, then b will be finalized after the */
412: /* next collection.) Any finalizable object that */
413: /* is reachable from itself by following one or more */
414: /* pointers will not be finalized (or collected). */
415: /* Thus cycles involving finalizable objects should */
416: /* be avoided, or broken by disappearing links. */
417: /* All but the last finalizer registered for an object */
418: /* is ignored. */
419: /* Finalization may be removed by passing 0 as fn. */
420: /* Finalizers are implicitly unregistered just before */
421: /* they are invoked. */
422: /* The old finalizer and client data are stored in */
423: /* *ofn and *ocd. */
424: /* Fn is never invoked on an accessible object, */
425: /* provided hidden pointers are converted to real */
426: /* pointers only if the allocation lock is held, and */
427: /* such conversions are not performed by finalization */
428: /* routines. */
429: /* If GC_register_finalizer is aborted as a result of */
430: /* a signal, the object may be left with no */
431: /* finalization, even if neither the old nor new */
432: /* finalizer were NULL. */
433: /* Obj should be the nonNULL starting address of an */
434: /* object allocated by GC_malloc or friends. */
435: /* Note that any garbage collectable object referenced */
436: /* by cd will be considered accessible until the */
437: /* finalizer is invoked. */
438:
439: /* Another versions of the above follow. It ignores */
440: /* self-cycles, i.e. pointers from a finalizable object to */
441: /* itself. There is a stylistic argument that this is wrong, */
442: /* but it's unavoidable for C++, since the compiler may */
443: /* silently introduce these. It's also benign in that specific */
444: /* case. */
445: GC_API void GC_register_finalizer_ignore_self
446: GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
447: GC_finalization_proc *ofn, GC_PTR *ocd));
448: GC_API void GC_debug_register_finalizer_ignore_self
449: GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
450: GC_finalization_proc *ofn, GC_PTR *ocd));
451:
452: /* The following routine may be used to break cycles between */
453: /* finalizable objects, thus causing cyclic finalizable */
454: /* objects to be finalized in the correct order. Standard */
455: /* use involves calling GC_register_disappearing_link(&p), */
456: /* where p is a pointer that is not followed by finalization */
457: /* code, and should not be considered in determining */
458: /* finalization order. */
459: GC_API int GC_register_disappearing_link GC_PROTO((GC_PTR * /* link */));
460: /* Link should point to a field of a heap allocated */
461: /* object obj. *link will be cleared when obj is */
462: /* found to be inaccessible. This happens BEFORE any */
463: /* finalization code is invoked, and BEFORE any */
464: /* decisions about finalization order are made. */
465: /* This is useful in telling the finalizer that */
466: /* some pointers are not essential for proper */
467: /* finalization. This may avoid finalization cycles. */
468: /* Note that obj may be resurrected by another */
469: /* finalizer, and thus the clearing of *link may */
470: /* be visible to non-finalization code. */
471: /* There's an argument that an arbitrary action should */
472: /* be allowed here, instead of just clearing a pointer. */
473: /* But this causes problems if that action alters, or */
474: /* examines connectivity. */
475: /* Returns 1 if link was already registered, 0 */
476: /* otherwise. */
477: /* Only exists for backward compatibility. See below: */
478:
479: GC_API int GC_general_register_disappearing_link
480: GC_PROTO((GC_PTR * /* link */, GC_PTR obj));
481: /* A slight generalization of the above. *link is */
482: /* cleared when obj first becomes inaccessible. This */
483: /* can be used to implement weak pointers easily and */
484: /* safely. Typically link will point to a location */
485: /* holding a disguised pointer to obj. (A pointer */
486: /* inside an "atomic" object is effectively */
487: /* disguised.) In this way soft */
488: /* pointers are broken before any object */
489: /* reachable from them are finalized. Each link */
490: /* May be registered only once, i.e. with one obj */
491: /* value. This was added after a long email discussion */
492: /* with John Ellis. */
493: /* Obj must be a pointer to the first word of an object */
494: /* we allocated. It is unsafe to explicitly deallocate */
495: /* the object containing link. Explicitly deallocating */
496: /* obj may or may not cause link to eventually be */
497: /* cleared. */
498: GC_API int GC_unregister_disappearing_link GC_PROTO((GC_PTR * /* link */));
499: /* Returns 0 if link was not actually registered. */
500: /* Undoes a registration by either of the above two */
501: /* routines. */
502:
503: /* Auxiliary fns to make finalization work correctly with displaced */
504: /* pointers introduced by the debugging allocators. */
505: GC_API GC_PTR GC_make_closure GC_PROTO((GC_finalization_proc fn, GC_PTR data));
506: GC_API void GC_debug_invoke_finalizer GC_PROTO((GC_PTR obj, GC_PTR data));
507:
508: GC_API int GC_invoke_finalizers GC_PROTO((void));
509: /* Run finalizers for all objects that are ready to */
510: /* be finalized. Return the number of finalizers */
511: /* that were run. Normally this is also called */
512: /* implicitly during some allocations. If */
513: /* FINALIZE_ON_DEMAND is defined, it must be called */
514: /* explicitly. */
515:
516: /* GC_set_warn_proc can be used to redirect or filter warning messages. */
517: /* p may not be a NULL pointer. */
518: typedef void (*GC_warn_proc) GC_PROTO((char *msg, GC_word arg));
519: GC_API GC_warn_proc GC_set_warn_proc GC_PROTO((GC_warn_proc p));
520: /* Returns old warning procedure. */
521:
522: /* The following is intended to be used by a higher level */
523: /* (e.g. cedar-like) finalization facility. It is expected */
524: /* that finalization code will arrange for hidden pointers to */
525: /* disappear. Otherwise objects can be accessed after they */
526: /* have been collected. */
527: /* Note that putting pointers in atomic objects or in */
528: /* nonpointer slots of "typed" objects is equivalent to */
529: /* disguising them in this way, and may have other advantages. */
530: # if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
531: typedef GC_word GC_hidden_pointer;
532: # define HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
533: # define REVEAL_POINTER(p) ((GC_PTR)(HIDE_POINTER(p)))
534: /* Converting a hidden pointer to a real pointer requires verifying */
535: /* that the object still exists. This involves acquiring the */
536: /* allocator lock to avoid a race with the collector. */
537: # endif /* I_HIDE_POINTERS */
538:
539: typedef GC_PTR (*GC_fn_type) GC_PROTO((GC_PTR client_data));
540: GC_API GC_PTR GC_call_with_alloc_lock
541: GC_PROTO((GC_fn_type fn, GC_PTR client_data));
542:
543: /* Check that p and q point to the same object. */
544: /* Fail conspicuously if they don't. */
545: /* Returns the first argument. */
546: /* Succeeds if neither p nor q points to the heap. */
547: /* May succeed if both p and q point to between heap objects. */
548: GC_API GC_PTR GC_same_obj GC_PROTO((GC_PTR p, GC_PTR q));
549:
550: /* Checked pointer pre- and post- increment operations. Note that */
551: /* the second argument is in units of bytes, not multiples of the */
552: /* object size. This should either be invoked from a macro, or the */
553: /* call should be automatically generated. */
554: GC_API GC_PTR GC_pre_incr GC_PROTO((GC_PTR *p, size_t how_much));
555: GC_API GC_PTR GC_post_incr GC_PROTO((GC_PTR *p, size_t how_much));
556:
557: /* Check that p is visible */
558: /* to the collector as a possibly pointer containing location. */
559: /* If it isn't fail conspicuously. */
560: /* Returns the argument in all cases. May erroneously succeed */
561: /* in hard cases. (This is intended for debugging use with */
562: /* untyped allocations. The idea is that it should be possible, though */
563: /* slow, to add such a call to all indirect pointer stores.) */
564: /* Currently useless for multithreaded worlds. */
565: GC_API GC_PTR GC_is_visible GC_PROTO((GC_PTR p));
566:
567: /* Check that if p is a pointer to a heap page, then it points to */
568: /* a valid displacement within a heap object. */
569: /* Fail conspicuously if this property does not hold. */
570: /* Uninteresting with ALL_INTERIOR_POINTERS. */
571: /* Always returns its argument. */
572: GC_API GC_PTR GC_is_valid_displacement GC_PROTO((GC_PTR p));
573:
574: /* Safer, but slow, pointer addition. Probably useful mainly with */
575: /* a preprocessor. Useful only for heap pointers. */
576: #ifdef GC_DEBUG
577: # define GC_PTR_ADD3(x, n, type_of_result) \
578: ((type_of_result)GC_same_obj((x)+(n), (x)))
579: # define GC_PRE_INCR3(x, n, type_of_result) \
580: ((type_of_result)GC_pre_incr(&(x), (n)*sizeof(*x))
581: # define GC_POST_INCR2(x, type_of_result) \
582: ((type_of_result)GC_post_incr(&(x), sizeof(*x))
583: # ifdef __GNUC__
584: # define GC_PTR_ADD(x, n) \
585: GC_PTR_ADD3(x, n, typeof(x))
586: # define GC_PRE_INCR(x, n) \
587: GC_PRE_INCR3(x, n, typeof(x))
588: # define GC_POST_INCR(x, n) \
589: GC_POST_INCR3(x, typeof(x))
590: # else
591: /* We can't do this right without typeof, which ANSI */
592: /* decided was not sufficiently useful. Repeatedly */
593: /* mentioning the arguments seems too dangerous to be */
594: /* useful. So does not casting the result. */
595: # define GC_PTR_ADD(x, n) ((x)+(n))
596: # endif
597: #else /* !GC_DEBUG */
598: # define GC_PTR_ADD3(x, n, type_of_result) ((x)+(n))
599: # define GC_PTR_ADD(x, n) ((x)+(n))
600: # define GC_PRE_INCR3(x, n, type_of_result) ((x) += (n))
601: # define GC_PRE_INCR(x, n) ((x) += (n))
602: # define GC_POST_INCR2(x, n, type_of_result) ((x)++)
603: # define GC_POST_INCR(x, n) ((x)++)
604: #endif
605:
606: /* Safer assignment of a pointer to a nonstack location. */
607: #ifdef GC_DEBUG
608: # ifdef __STDC__
609: # define GC_PTR_STORE(p, q) \
610: (*(void **)GC_is_visible(p) = GC_is_valid_displacement(q))
611: # else
612: # define GC_PTR_STORE(p, q) \
613: (*(char **)GC_is_visible(p) = GC_is_valid_displacement(q))
614: # endif
615: #else /* !GC_DEBUG */
616: # define GC_PTR_STORE(p, q) *((p) = (q))
617: #endif
618:
619: /* Fynctions called to report pointer checking errors */
620: GC_API void (*GC_same_obj_print_proc) GC_PROTO((GC_PTR p, GC_PTR q));
621:
622: GC_API void (*GC_is_valid_displacement_print_proc)
623: GC_PROTO((GC_PTR p));
624:
625: GC_API void (*GC_is_visible_print_proc)
626: GC_PROTO((GC_PTR p));
627:
628: #if defined(_SOLARIS_PTHREADS) && !defined(SOLARIS_THREADS)
629: # define SOLARIS_THREADS
630: #endif
631:
632: #ifdef SOLARIS_THREADS
633: /* We need to intercept calls to many of the threads primitives, so */
634: /* that we can locate thread stacks and stop the world. */
635: /* Note also that the collector cannot see thread specific data. */
636: /* Thread specific data should generally consist of pointers to */
637: /* uncollectable objects, which are deallocated using the destructor */
638: /* facility in thr_keycreate. */
639: # include <thread.h>
640: # include <signal.h>
641: int GC_thr_create(void *stack_base, size_t stack_size,
642: void *(*start_routine)(void *), void *arg, long flags,
643: thread_t *new_thread);
644: int GC_thr_join(thread_t wait_for, thread_t *departed, void **status);
645: int GC_thr_suspend(thread_t target_thread);
646: int GC_thr_continue(thread_t target_thread);
647: void * GC_dlopen(const char *path, int mode);
648:
649: # ifdef _SOLARIS_PTHREADS
650: # include <pthread.h>
651: extern int GC_pthread_create(pthread_t *new_thread,
652: const pthread_attr_t *attr,
653: void * (*thread_execp)(void *), void *arg);
654: extern int GC_pthread_join(pthread_t wait_for, void **status);
655:
656: # undef thread_t
657:
658: # define pthread_join GC_pthread_join
659: # define pthread_create GC_pthread_create
660: #endif
661:
662: # define thr_create GC_thr_create
663: # define thr_join GC_thr_join
664: # define thr_suspend GC_thr_suspend
665: # define thr_continue GC_thr_continue
666: # define dlopen GC_dlopen
667:
668: # endif /* SOLARIS_THREADS */
669:
670:
671: #if defined(IRIX_THREADS) || defined(LINUX_THREADS)
672: /* We treat these similarly. */
673: # include <pthread.h>
674: # include <signal.h>
675:
676: int GC_pthread_create(pthread_t *new_thread,
677: const pthread_attr_t *attr,
678: void *(*start_routine)(void *), void *arg);
679: int GC_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset);
680: int GC_pthread_join(pthread_t thread, void **retval);
681:
682: # define pthread_create GC_pthread_create
683: # define pthread_sigmask GC_pthread_sigmask
684: # define pthread_join GC_pthread_join
685:
686: #endif /* IRIX_THREADS || LINUX_THREADS */
687:
688: # if defined(PCR) || defined(SOLARIS_THREADS) || defined(WIN32_THREADS) || \
689: defined(IRIX_THREADS) || defined(LINUX_THREADS) || \
690: defined(IRIX_JDK_THREADS)
691: /* Any flavor of threads except SRC_M3. */
692: /* This returns a list of objects, linked through their first */
693: /* word. Its use can greatly reduce lock contention problems, since */
694: /* the allocation lock can be acquired and released many fewer times. */
695: GC_PTR GC_malloc_many(size_t lb);
696: #define GC_NEXT(p) (*(GC_PTR *)(p)) /* Retrieve the next element */
697: /* in returned list. */
698: extern void GC_thr_init(); /* Needed for Solaris/X86 */
699:
700: #endif /* THREADS && !SRC_M3 */
701:
702: /*
703: * If you are planning on putting
704: * the collector in a SunOS 5 dynamic library, you need to call GC_INIT()
705: * from the statically loaded program section.
706: * This circumvents a Solaris 2.X (X<=4) linker bug.
707: */
708: #if defined(sparc) || defined(__sparc)
709: # define GC_INIT() { extern end, etext; \
710: GC_noop(&end, &etext); }
711: #else
712: # if defined(__CYGWIN32__) && defined(GC_USE_DLL)
713: /*
714: * Similarly gnu-win32 DLLs need explicit initialization
715: */
716: # define GC_INIT() { GC_add_roots(DATASTART, DATAEND); }
717: # else
718: # define GC_INIT()
719: # endif
720: #endif
721:
722: #if (defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \
723: || defined(_WIN32)
724: /* win32S may not free all resources on process exit. */
725: /* This explicitly deallocates the heap. */
726: GC_API void GC_win32_free_heap ();
727: #endif
728:
729: #ifdef __cplusplus
730: } /* end of extern "C" */
731: #endif
732:
733: #endif /* _GC_H */
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