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, October 9, 1995 1:14 pm PDT */
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
32 # if defined(__STDC__) || defined(__cplusplus)
33 # define GC_PROTO(args) args
34 typedef void * GC_PTR;
36 # define GC_PROTO(args) ()
37 typedef char * GC_PTR;
46 /* Define word and signed_word to be unsigned and signed types of the */
47 /* size as char * or void *. There seems to be no way to do this */
48 /* even semi-portably. The following is probably no better/worse */
49 /* than almost anything else. */
50 /* The ANSI standard suggests that size_t and ptr_diff_t might be */
51 /* better choices. But those appear to have incorrect definitions */
52 /* on may systems. Notably "typedef int size_t" seems to be both */
53 /* frequent and WRONG. */
54 typedef unsigned long GC_word;
55 typedef long GC_signed_word;
57 /* Public read-only variables */
59 extern GC_word GC_gc_no;/* Counter incremented per collection. */
60 /* Includes empty GCs at startup. */
63 /* Public R/W variables */
65 extern int GC_quiet; /* Disable statistics output. Only matters if */
66 /* collector has been compiled with statistics */
67 /* enabled. This involves a performance cost, */
68 /* and is thus not the default. */
70 extern int GC_dont_gc; /* Dont collect unless explicitly requested, e.g. */
71 /* beacuse it's not safe. */
73 extern int GC_dont_expand;
74 /* Dont expand heap unless explicitly requested */
77 extern int GC_full_freq; /* Number of partial collections between */
78 /* full collections. Matters only if */
79 /* GC_incremental is set. */
81 extern GC_word GC_non_gc_bytes;
82 /* Bytes not considered candidates for collection. */
83 /* Used only to control scheduling of collections. */
85 extern GC_word GC_free_space_divisor;
86 /* We try to make sure that we allocate at */
87 /* least N/GC_free_space_divisor bytes between */
88 /* collections, where N is the heap size plus */
89 /* a rough estimate of the root set size. */
90 /* Initially, GC_free_space_divisor = 4. */
91 /* Increasing its value will use less space */
92 /* but more collection time. Decreasing it */
93 /* will appreciably decrease collection time */
94 /* at the expense of space. */
95 /* GC_free_space_divisor = 1 will effectively */
96 /* disable collections. */
99 /* Public procedures */
101 * general purpose allocation routines, with roughly malloc calling conv.
102 * The atomic versions promise that no relevant pointers are contained
103 * in the object. The nonatomic versions guarantee that the new object
104 * is cleared. GC_malloc_stubborn promises that no changes to the object
105 * will occur after GC_end_stubborn_change has been called on the
106 * result of GC_malloc_stubborn. GC_malloc_uncollectable allocates an object
107 * that is scanned for pointers to collectable objects, but is not itself
108 * collectable. GC_malloc_uncollectable and GC_free called on the resulting
109 * object implicitly update GC_non_gc_bytes appropriately.
111 extern GC_PTR GC_malloc GC_PROTO((size_t size_in_bytes));
112 extern GC_PTR GC_malloc_atomic GC_PROTO((size_t size_in_bytes));
113 extern GC_PTR GC_malloc_uncollectable GC_PROTO((size_t size_in_bytes));
114 extern GC_PTR GC_malloc_stubborn GC_PROTO((size_t size_in_bytes));
116 /* Explicitly deallocate an object. Dangerous if used incorrectly. */
117 /* Requires a pointer to the base of an object. */
118 /* If the argument is stubborn, it should not be changeable when freed. */
119 /* An object should not be enable for finalization when it is */
120 /* explicitly deallocated. */
121 /* GC_free(0) is a no-op, as required by ANSI C for free. */
122 extern void GC_free GC_PROTO((GC_PTR object_addr));
125 * Stubborn objects may be changed only if the collector is explicitly informed.
126 * The collector is implicitly informed of coming change when such
127 * an object is first allocated. The following routines inform the
128 * collector that an object will no longer be changed, or that it will
129 * once again be changed. Only nonNIL pointer stores into the object
130 * are considered to be changes. The argument to GC_end_stubborn_change
131 * must be exacly the value returned by GC_malloc_stubborn or passed to
132 * GC_change_stubborn. (In the second case it may be an interior pointer
133 * within 512 bytes of the beginning of the objects.)
134 * There is a performance penalty for allowing more than
135 * one stubborn object to be changed at once, but it is acceptable to
136 * do so. The same applies to dropping stubborn objects that are still
139 extern void GC_change_stubborn GC_PROTO((GC_PTR));
140 extern void GC_end_stubborn_change GC_PROTO((GC_PTR));
142 /* Return a pointer to the base (lowest address) of an object given */
143 /* a pointer to a location within the object. */
144 /* Return 0 if displaced_pointer doesn't point to within a valid */
146 extern GC_PTR GC_base GC_PROTO((GC_PTR displaced_pointer));
148 /* Given a pointer to the base of an object, return its size in bytes. */
149 /* The returned size may be slightly larger than what was originally */
151 extern size_t GC_size GC_PROTO((GC_PTR object_addr));
153 /* For compatibility with C library. This is occasionally faster than */
154 /* a malloc followed by a bcopy. But if you rely on that, either here */
155 /* or with the standard C library, your code is broken. In my */
156 /* opinion, it shouldn't have been invented, but now we're stuck. -HB */
157 /* The resulting object has the same kind as the original. */
158 /* If the argument is stubborn, the result will have changes enabled. */
159 /* It is an error to have changes enabled for the original object. */
160 /* Follows ANSI comventions for NULL old_object. */
161 extern GC_PTR GC_realloc GC_PROTO((GC_PTR old_object,
162 size_t new_size_in_bytes));
164 /* Explicitly increase the heap size. */
165 /* Returns 0 on failure, 1 on success. */
166 extern int GC_expand_hp GC_PROTO((size_t number_of_bytes));
168 /* Limit the heap size to n bytes. Useful when you're debugging, */
169 /* especially on systems that don't handle running out of memory well. */
170 /* n == 0 ==> unbounded. This is the default. */
171 extern void GC_set_max_heap_size GC_PROTO((GC_word n));
173 /* Clear the set of root segments. Wizards only. */
174 extern void GC_clear_roots GC_PROTO((void));
176 /* Add a root segment. Wizards only. */
177 extern void GC_add_roots GC_PROTO((char * low_address,
178 char * high_address_plus_1));
180 /* Add a displacement to the set of those considered valid by the */
181 /* collector. GC_register_displacement(n) means that if p was returned */
182 /* by GC_malloc, then (char *)p + n will be considered to be a valid */
183 /* pointer to n. N must be small and less than the size of p. */
184 /* (All pointers to the interior of objects from the stack are */
185 /* considered valid in any case. This applies to heap objects and */
187 /* Preferably, this should be called before any other GC procedures. */
188 /* Calling it later adds to the probability of excess memory */
190 /* This is a no-op if the collector was compiled with recognition of */
191 /* arbitrary interior pointers enabled, which is now the default. */
192 void GC_register_displacement GC_PROTO((GC_word n));
194 /* The following version should be used if any debugging allocation is */
196 void GC_debug_register_displacement GC_PROTO((GC_word n));
198 /* Explicitly trigger a full, world-stop collection. */
199 void GC_gcollect GC_PROTO((void));
201 /* Trigger a full world-stopped collection. Abort the collection if */
202 /* and when stop_func returns a nonzero value. Stop_func will be */
203 /* called frequently, and should be reasonably fast. This works even */
204 /* if virtual dirty bits, and hence incremental collection is not */
205 /* available for this architecture. Collections can be aborted faster */
206 /* than normal pause times for incremental collection. However, */
207 /* aborted collections do no useful work; the next collection needs */
208 /* to start from the beginning. */
209 typedef int (* GC_stop_func) GC_PROTO((void));
210 int GC_try_to_collect GC_PROTO((GC_stop_func stop_func));
212 /* Return the number of bytes in the heap. Excludes collector private */
213 /* data structures. Includes empty blocks and fragmentation loss. */
214 /* Includes some pages that were allocated but never written. */
215 size_t GC_get_heap_size GC_PROTO((void));
217 /* Return the number of bytes allocated since the last collection. */
218 size_t GC_get_bytes_since_gc GC_PROTO((void));
220 /* Enable incremental/generational collection. */
221 /* Not advisable unless dirty bits are */
222 /* available or most heap objects are */
223 /* pointerfree(atomic) or immutable. */
224 /* Don't use in leak finding mode. */
225 /* Ignored if GC_dont_gc is true. */
226 void GC_enable_incremental GC_PROTO((void));
228 /* Perform some garbage collection work, if appropriate. */
229 /* Return 0 if there is no more work to be done. */
230 /* Typically performs an amount of work corresponding roughly */
231 /* to marking from one page. May do more work if further */
232 /* progress requires it, e.g. if incremental collection is */
233 /* disabled. It is reasonable to call this in a wait loop */
234 /* until it returns 0. */
235 int GC_collect_a_little GC_PROTO((void));
237 /* Allocate an object of size lb bytes. The client guarantees that */
238 /* as long as the object is live, it will be referenced by a pointer */
239 /* that points to somewhere within the first 256 bytes of the object. */
240 /* (This should normally be declared volatile to prevent the compiler */
241 /* from invalidating this assertion.) This routine is only useful */
242 /* if a large array is being allocated. It reduces the chance of */
243 /* accidentally retaining such an array as a result of scanning an */
244 /* integer that happens to be an address inside the array. (Actually, */
245 /* it reduces the chance of the allocator not finding space for such */
246 /* an array, since it will try hard to avoid introducing such a false */
247 /* reference.) On a SunOS 4.X or MS Windows system this is recommended */
248 /* for arrays likely to be larger than 100K or so. For other systems, */
249 /* or if the collector is not configured to recognize all interior */
250 /* pointers, the threshold is normally much higher. */
251 extern GC_PTR GC_malloc_ignore_off_page GC_PROTO((size_t lb));
252 extern GC_PTR GC_malloc_atomic_ignore_off_page GC_PROTO((size_t lb));
254 /* Debugging (annotated) allocation. GC_gcollect will check */
255 /* objects allocated in this way for overwrites, etc. */
256 extern GC_PTR GC_debug_malloc
257 GC_PROTO((size_t size_in_bytes, char * descr_string, int descr_int));
258 extern GC_PTR GC_debug_malloc_atomic
259 GC_PROTO((size_t size_in_bytes, char * descr_string, int descr_int));
260 extern GC_PTR GC_debug_malloc_uncollectable
261 GC_PROTO((size_t size_in_bytes, char * descr_string, int descr_int));
262 extern GC_PTR GC_debug_malloc_stubborn
263 GC_PROTO((size_t size_in_bytes, char * descr_string, int descr_int));
264 extern void GC_debug_free GC_PROTO((GC_PTR object_addr));
265 extern GC_PTR GC_debug_realloc
266 GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes,
267 char * descr_string, int descr_int));
269 void GC_debug_change_stubborn GC_PROTO((GC_PTR));
270 void GC_debug_end_stubborn_change GC_PROTO((GC_PTR));
272 # define GC_MALLOC(sz) GC_debug_malloc(sz, __FILE__, __LINE__)
273 # define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, __FILE__, __LINE__)
274 # define GC_MALLOC_UNCOLLECTABLE(sz) GC_debug_malloc_uncollectable(sz, \
276 # define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, __FILE__, \
278 # define GC_FREE(p) GC_debug_free(p)
279 # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
280 GC_register_finalizer(GC_base(p), GC_debug_invoke_finalizer, \
281 GC_make_closure(f,d), of, od)
282 # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
283 GC_register_finalizer_ignore_self( \
284 GC_base(p), GC_debug_invoke_finalizer, \
285 GC_make_closure(f,d), of, od)
286 # define GC_MALLOC_STUBBORN(sz) GC_debug_malloc_stubborn(sz, __FILE__, \
288 # define GC_CHANGE_STUBBORN(p) GC_debug_change_stubborn(p)
289 # define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
290 # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
291 GC_general_register_disappearing_link(link, GC_base(obj))
292 # define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
294 # define GC_MALLOC(sz) GC_malloc(sz)
295 # define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
296 # define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz)
297 # define GC_REALLOC(old, sz) GC_realloc(old, sz)
298 # define GC_FREE(p) GC_free(p)
299 # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
300 GC_register_finalizer(p, f, d, of, od)
301 # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
302 GC_register_finalizer_ignore_self(p, f, d, of, od)
303 # define GC_MALLOC_STUBBORN(sz) GC_malloc_stubborn(sz)
304 # define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p)
305 # define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
306 # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
307 GC_general_register_disappearing_link(link, obj)
308 # define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
310 /* The following are included because they are often convenient, and */
311 /* reduce the chance for a misspecifed size argument. But calls may */
312 /* expand to something syntactically incorrect if t is a complicated */
313 /* type expression. */
314 # define GC_NEW(t) (t *)GC_MALLOC(sizeof (t))
315 # define GC_NEW_ATOMIC(t) (t *)GC_MALLOC_ATOMIC(sizeof (t))
316 # define GC_NEW_STUBBORN(t) (t *)GC_MALLOC_STUBBORN(sizeof (t))
317 # define GC_NEW_UNCOLLECTABLE(t) (t *)GC_MALLOC_UNCOLLECTABLE(sizeof (t))
319 /* Finalization. Some of these primitives are grossly unsafe. */
320 /* The idea is to make them both cheap, and sufficient to build */
321 /* a safer layer, closer to PCedar finalization. */
322 /* The interface represents my conclusions from a long discussion */
323 /* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes, */
324 /* Christian Jacobi, and Russ Atkinson. It's not perfect, and */
325 /* probably nobody else agrees with it. Hans-J. Boehm 3/13/92 */
326 typedef void (*GC_finalization_proc)
327 GC_PROTO((GC_PTR obj, GC_PTR client_data));
329 extern void GC_register_finalizer
330 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
331 GC_finalization_proc *ofn, GC_PTR *ocd));
332 /* When obj is no longer accessible, invoke */
333 /* (*fn)(obj, cd). If a and b are inaccessible, and */
334 /* a points to b (after disappearing links have been */
335 /* made to disappear), then only a will be */
336 /* finalized. (If this does not create any new */
337 /* pointers to b, then b will be finalized after the */
338 /* next collection.) Any finalizable object that */
339 /* is reachable from itself by following one or more */
340 /* pointers will not be finalized (or collected). */
341 /* Thus cycles involving finalizable objects should */
342 /* be avoided, or broken by disappearing links. */
343 /* Fn should terminate as quickly as possible, and */
344 /* defer extended computation. */
345 /* All but the last finalizer registered for an object */
347 /* Finalization may be removed by passing 0 as fn. */
348 /* The old finalizer and client data are stored in */
350 /* Fn is never invoked on an accessible object, */
351 /* provided hidden pointers are converted to real */
352 /* pointers only if the allocation lock is held, and */
353 /* such conversions are not performed by finalization */
355 /* If GC_register_finalizer is aborted as a result of */
356 /* a signal, the object may be left with no */
357 /* finalization, even if neither the old nor new */
358 /* finalizer were NULL. */
359 /* Obj should be the nonNULL starting address of an */
360 /* object allocated by GC_malloc or friends. */
361 /* Note that any garbage collectable object referenced */
362 /* by cd will be considered accessible until the */
363 /* finalizer is invoked. */
365 /* Another versions of the above follow. It ignores */
366 /* self-cycles, i.e. pointers from a finalizable object to */
367 /* itself. There is a stylistic argument that this is wrong, */
368 /* but it's unavoidable for C++, since the compiler may */
369 /* silently introduce these. It's also benign in that specific */
371 extern void GC_register_finalizer_ignore_self
372 GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
373 GC_finalization_proc *ofn, GC_PTR *ocd));
375 /* The following routine may be used to break cycles between */
376 /* finalizable objects, thus causing cyclic finalizable */
377 /* objects to be finalized in the correct order. Standard */
378 /* use involves calling GC_register_disappearing_link(&p), */
379 /* where p is a pointer that is not followed by finalization */
380 /* code, and should not be considered in determining */
381 /* finalization order. */
382 extern int GC_register_disappearing_link GC_PROTO((GC_PTR * /* link */));
383 /* Link should point to a field of a heap allocated */
384 /* object obj. *link will be cleared when obj is */
385 /* found to be inaccessible. This happens BEFORE any */
386 /* finalization code is invoked, and BEFORE any */
387 /* decisions about finalization order are made. */
388 /* This is useful in telling the finalizer that */
389 /* some pointers are not essential for proper */
390 /* finalization. This may avoid finalization cycles. */
391 /* Note that obj may be resurrected by another */
392 /* finalizer, and thus the clearing of *link may */
393 /* be visible to non-finalization code. */
394 /* There's an argument that an arbitrary action should */
395 /* be allowed here, instead of just clearing a pointer. */
396 /* But this causes problems if that action alters, or */
397 /* examines connectivity. */
398 /* Returns 1 if link was already registered, 0 */
400 /* Only exists for backward compatibility. See below: */
402 extern int GC_general_register_disappearing_link
403 GC_PROTO((GC_PTR * /* link */, GC_PTR obj));
404 /* A slight generalization of the above. *link is */
405 /* cleared when obj first becomes inaccessible. This */
406 /* can be used to implement weak pointers easily and */
407 /* safely. Typically link will point to a location */
408 /* holding a disguised pointer to obj. (A pointer */
409 /* inside an "atomic" object is effectively */
410 /* disguised.) In this way soft */
411 /* pointers are broken before any object */
412 /* reachable from them are finalized. Each link */
413 /* May be registered only once, i.e. with one obj */
414 /* value. This was added after a long email discussion */
415 /* with John Ellis. */
416 /* Obj must be a pointer to the first word of an object */
417 /* we allocated. It is unsafe to explicitly deallocate */
418 /* the object containing link. Explicitly deallocating */
419 /* obj may or may not cause link to eventually be */
421 extern int GC_unregister_disappearing_link GC_PROTO((GC_PTR * /* link */));
422 /* Returns 0 if link was not actually registered. */
423 /* Undoes a registration by either of the above two */
426 /* Auxiliary fns to make finalization work correctly with displaced */
427 /* pointers introduced by the debugging allocators. */
428 extern GC_PTR GC_make_closure GC_PROTO((GC_finalization_proc fn, GC_PTR data));
429 extern void GC_debug_invoke_finalizer GC_PROTO((GC_PTR obj, GC_PTR data));
431 /* GC_set_warn_proc can be used to redirect or filter warning messages. */
432 typedef void (*GC_warn_proc) GC_PROTO((char *msg, GC_word arg));
433 extern GC_warn_proc GC_set_warn_proc GC_PROTO((GC_warn_proc p));
434 /* Returns old warning procedure. */
436 /* The following is intended to be used by a higher level */
437 /* (e.g. cedar-like) finalization facility. It is expected */
438 /* that finalization code will arrange for hidden pointers to */
439 /* disappear. Otherwise objects can be accessed after they */
440 /* have been collected. */
441 /* Note that putting pointers in atomic objects or in */
442 /* nonpointer slots of "typed" objects is equivalent to */
443 /* disguising them in this way, and may have other advantages. */
444 # if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
445 typedef GC_word GC_hidden_pointer;
446 # define HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
447 # define REVEAL_POINTER(p) ((GC_PTR)(HIDE_POINTER(p)))
448 /* Converting a hidden pointer to a real pointer requires verifying */
449 /* that the object still exists. This involves acquiring the */
450 /* allocator lock to avoid a race with the collector. */
451 # endif /* I_HIDE_POINTERS */
453 typedef GC_PTR (*GC_fn_type) GC_PROTO((GC_PTR client_data));
454 extern GC_PTR GC_call_with_alloc_lock
455 GC_PROTO((GC_fn_type fn, GC_PTR client_data));
457 /* Check that p and q point to the same object. */
458 /* Fail conspicuously if they don't. */
459 /* Returns the first argument. */
460 /* Succeeds if neither p nor q points to the heap. */
461 /* May succeed if both p and q point to between heap objects. */
462 extern GC_PTR GC_same_obj GC_PROTO((GC_PTR p, GC_PTR q));
464 /* Checked pointer pre- and post- increment operations. Note that */
465 /* the second argument is in units of bytes, not multiples of the */
466 /* object size. This should either be invoked from a macro, or the */
467 /* call should be automatically generated. */
468 extern GC_PTR GC_pre_incr GC_PROTO((GC_PTR *p, size_t how_much));
469 extern GC_PTR GC_post_incr GC_PROTO((GC_PTR *p, size_t how_much));
471 /* Check that p is visible */
472 /* to the collector as a possibly pointer containing location. */
473 /* If it isn't fail conspicuously. */
474 /* Returns the argument in all cases. May erroneously succeed */
475 /* in hard cases. (This is intended for debugging use with */
476 /* untyped allocations. The idea is that it should be possible, though */
477 /* slow, to add such a call to all indirect pointer stores.) */
478 /* Currently useless for multithreaded worlds. */
479 extern GC_PTR GC_is_visible GC_PROTO((GC_PTR p));
481 /* Check that if p is a pointer to a heap page, then it points to */
482 /* a valid displacement within a heap object. */
483 /* Fail conspicuously if this property does not hold. */
484 /* Uninteresting with ALL_INTERIOR_POINTERS. */
485 /* Always returns its argument. */
486 extern GC_PTR GC_is_valid_displacement GC_PROTO((GC_PTR p));
488 /* Safer, but slow, pointer addition. Probably useful mainly with */
489 /* a preprocessor. Useful only for heap pointers. */
491 # define GC_PTR_ADD3(x, n, type_of_result) \
492 ((type_of_result)GC_same_obj((x)+(n), (x)))
493 # define GC_PRE_INCR3(x, n, type_of_result) \
494 ((type_of_result)GC_pre_incr(&(x), (n)*sizeof(*x))
495 # define GC_POST_INCR2(x, type_of_result) \
496 ((type_of_result)GC_post_incr(&(x), sizeof(*x))
498 # define GC_PTR_ADD(x, n) \
499 GC_PTR_ADD3(x, n, typeof(x))
500 # define GC_PRE_INCR(x, n) \
501 GC_PRE_INCR3(x, n, typeof(x))
502 # define GC_POST_INCR(x, n) \
503 GC_POST_INCR3(x, typeof(x))
505 /* We can't do this right without typeof, which ANSI */
506 /* decided was not sufficiently useful. Repeatedly */
507 /* mentioning the arguments seems too dangerous to be */
508 /* useful. So does not casting the result. */
509 # define GC_PTR_ADD(x, n) ((x)+(n))
511 #else /* !GC_DEBUG */
512 # define GC_PTR_ADD3(x, n, type_of_result) ((x)+(n))
513 # define GC_PTR_ADD(x, n) ((x)+(n))
514 # define GC_PRE_INCR3(x, n, type_of_result) ((x) += (n))
515 # define GC_PRE_INCR(x, n) ((x) += (n))
516 # define GC_POST_INCR2(x, n, type_of_result) ((x)++)
517 # define GC_POST_INCR(x, n) ((x)++)
520 /* Safer assignment of a pointer to a nonstack location. */
523 # define GC_PTR_STORE(p, q) \
524 (*(void **)GC_is_visible(p) = GC_is_valid_displacement(q))
526 # define GC_PTR_STORE(p, q) \
527 (*(char **)GC_is_visible(p) = GC_is_valid_displacement(q))
529 #else /* !GC_DEBUG */
530 # define GC_PTR_STORE(p, q) *((p) = (q))
534 #ifdef SOLARIS_THREADS
535 /* We need to intercept calls to many of the threads primitives, so */
536 /* that we can locate thread stacks and stop the world. */
537 /* Note also that the collector cannot see thread specific data. */
538 /* Thread specific data should generally consist of pointers to */
539 /* uncollectable objects, which are deallocated using the destructor */
540 /* facility in thr_keycreate. */
543 int GC_thr_create(void *stack_base, size_t stack_size,
544 void *(*start_routine)(void *), void *arg, long flags,
545 thread_t *new_thread);
546 int GC_thr_join(thread_t wait_for, thread_t *departed, void **status);
547 int GC_thr_suspend(thread_t target_thread);
548 int GC_thr_continue(thread_t target_thread);
549 void * GC_dlopen(const char *path, int mode);
551 # define thr_create GC_thr_create
552 # define thr_join GC_thr_join
553 # define thr_suspend GC_thr_suspend
554 # define thr_continue GC_thr_continue
555 # define dlopen GC_dlopen
557 /* This returns a list of objects, linked through their first */
558 /* word. Its use can greatly reduce lock contention problems, since */
559 /* the allocation lock can be acquired and released many fewer times. */
560 GC_PTR GC_malloc_many(size_t lb);
561 #define GC_NEXT(p) (*(GC_PTR *)(p)) /* Retrieve the next element */
562 /* in returned list. */
564 #endif /* SOLARIS_THREADS */
567 * If you are planning on putting
568 * the collector in a SunOS 5 dynamic library, you need to call GC_INIT()
569 * from the statically loaded program section.
570 * This circumvents a Solaris 2.X (X<=4) linker bug.
572 #if defined(sparc) || defined(__sparc)
573 # define GC_INIT() { extern end, etext; \
574 GC_noop(&end, &etext); }
580 } /* end of extern "C" */
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