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   #include <stdint.h>
65   typedef unsigned __int64 GC_word;
66   typedef __int64 GC_signed_word;
67 #endif
68 
69 /* Public read-only variables */
70 
71 GC_API GC_word GC_gc_no;/* Counter incremented per collection.  	*/
72 			/* Includes empty GCs at startup.		*/
73 
74 GC_API int GC_parallel;	/* GC is parallelized for performance on	*/
75 			/* multiprocessors.  Currently set only		*/
76 			/* implicitly if collector is built with	*/
77 			/* -DPARALLEL_MARK and if either:		*/
78 			/*  Env variable GC_NPROC is set to > 1, or	*/
79 			/*  GC_NPROC is not set and this is an MP.	*/
80 			/* If GC_parallel is set, incremental		*/
81 			/* collection is only partially functional,	*/
82 			/* and may not be desirable.			*/
83 
84 
85 /* Public R/W variables */
86 
87 GC_API GC_PTR (*GC_oom_fn) GC_PROTO((size_t bytes_requested));
88 			/* When there is insufficient memory to satisfy */
89 			/* an allocation request, we return		*/
90 			/* (*GC_oom_fn)().  By default this just	*/
91 			/* returns 0.					*/
92 			/* If it returns, it must return 0 or a valid	*/
93 			/* pointer to a previously allocated heap 	*/
94 			/* object.					*/
95 
96 typedef enum {
97 	GC_EVENT_START,
98 	GC_EVENT_MARK_START,
99 	GC_EVENT_MARK_END,
100 	GC_EVENT_RECLAIM_START,
101 	GC_EVENT_RECLAIM_END,
102 	GC_EVENT_END,
103 	GC_EVENT_PRE_STOP_WORLD,
104 	GC_EVENT_POST_STOP_WORLD,
105 	GC_EVENT_PRE_START_WORLD,
106 	GC_EVENT_POST_START_WORLD
107 } GC_EventType;
108 
109 GC_API void GC_set_on_collection_event GC_PROTO((void (*) (GC_EventType)));
110 			/* Set callback invoked at specific points	*/
111 			/* during every collection.			*/
112 
113 GC_API void (*GC_on_heap_resize) GC_PROTO((size_t new_size));
114 			/* Invoked when the heap grows or shrinks        */
115 
116 GC_API int GC_find_leak;
117 			/* Do not actually garbage collect, but simply	*/
118 			/* report inaccessible memory that was not	*/
119 			/* deallocated with GC_free.  Initial value	*/
120 			/* is determined by FIND_LEAK macro.		*/
121 
122 GC_API int GC_all_interior_pointers;
123 			/* Arrange for pointers to object interiors to	*/
124 			/* be recognized as valid.  May not be changed	*/
125 			/* after GC initialization.			*/
126 			/* Initial value is determined by 		*/
127 			/* -DALL_INTERIOR_POINTERS.			*/
128 			/* Unless DONT_ADD_BYTE_AT_END is defined, this	*/
129 			/* also affects whether sizes are increased by	*/
130 			/* at least a byte to allow "off the end"	*/
131 			/* pointer recognition.				*/
132 			/* MUST BE 0 or 1.				*/
133 
134 GC_API int GC_quiet;	/* Disable statistics output.  Only matters if	*/
135 			/* collector has been compiled with statistics	*/
136 			/* enabled.  This involves a performance cost,	*/
137 			/* and is thus not the default.			*/
138 
139 GC_API int GC_finalize_on_demand;
140 			/* If nonzero, finalizers will only be run in 	*/
141 			/* response to an explicit GC_invoke_finalizers	*/
142 			/* call.  The default is determined by whether	*/
143 			/* the FINALIZE_ON_DEMAND macro is defined	*/
144 			/* when the collector is built.			*/
145 
146 GC_API int GC_java_finalization;
147 			/* Mark objects reachable from finalizable 	*/
148 			/* objects in a separate postpass.  This makes	*/
149 			/* it a bit safer to use non-topologically-	*/
150 			/* ordered finalization.  Default value is	*/
151 			/* determined by JAVA_FINALIZATION macro.	*/
152 
153 GC_API void (* GC_finalizer_notifier)(void);
154 			/* Invoked by the collector when there are 	*/
155 			/* objects to be finalized.  Invoked at most	*/
156 			/* once per GC cycle.  Never invoked unless 	*/
157 			/* GC_finalize_on_demand is set.		*/
158 			/* Typically this will notify a finalization	*/
159 			/* thread, which will call GC_invoke_finalizers */
160 			/* in response.					*/
161 
162 GC_API int GC_dont_gc;	/* != 0 ==> Dont collect.  In versions 6.2a1+,	*/
163 			/* this overrides explicit GC_gcollect() calls.	*/
164 			/* Used as a counter, so that nested enabling	*/
165 			/* and disabling work correctly.  Should	*/
166 			/* normally be updated with GC_enable() and	*/
167 			/* GC_disable() calls.				*/
168 			/* Direct assignment to GC_dont_gc is 		*/
169 			/* deprecated.					*/
170 
171 GC_API int GC_dont_expand;
172 			/* Dont expand heap unless explicitly requested */
173 			/* or forced to.				*/
174 
175 GC_API int GC_use_entire_heap;
176 		/* Causes the nonincremental collector to use the	*/
177 		/* entire heap before collecting.  This was the only 	*/
178 		/* option for GC versions < 5.0.  This sometimes	*/
179 		/* results in more large block fragmentation, since	*/
180 		/* very larg blocks will tend to get broken up		*/
181 		/* during each GC cycle.  It is likely to result in a	*/
182 		/* larger working set, but lower collection		*/
183 		/* frequencies, and hence fewer instructions executed	*/
184 		/* in the collector.					*/
185 
186 GC_API int GC_full_freq;    /* Number of partial collections between	*/
187 			    /* full collections.  Matters only if	*/
188 			    /* GC_incremental is set.			*/
189 			    /* Full collections are also triggered if	*/
190 			    /* the collector detects a substantial	*/
191 			    /* increase in the number of in-use heap	*/
192 			    /* blocks.  Values in the tens are now	*/
193 			    /* perfectly reasonable, unlike for		*/
194 			    /* earlier GC versions.			*/
195 
196 GC_API GC_word GC_non_gc_bytes;
197 			/* Bytes not considered candidates for collection. */
198 			/* Used only to control scheduling of collections. */
199 			/* Updated by GC_malloc_uncollectable and GC_free. */
200 			/* Wizards only.				   */
201 
202 GC_API int GC_no_dls;
203 			/* Don't register dynamic library data segments. */
204 			/* Wizards only.  Should be used only if the	 */
205 			/* application explicitly registers all roots.	 */
206 			/* In Microsoft Windows environments, this will	 */
207 			/* usually also prevent registration of the	 */
208 			/* main data segment as part of the root set.	 */
209 
210 GC_API GC_word GC_free_space_divisor;
211 			/* We try to make sure that we allocate at 	*/
212 			/* least N/GC_free_space_divisor bytes between	*/
213 			/* collections, where N is the heap size plus	*/
214 			/* a rough estimate of the root set size.	*/
215 			/* Initially, GC_free_space_divisor = 3.	*/
216 			/* Increasing its value will use less space	*/
217 			/* but more collection time.  Decreasing it	*/
218 			/* will appreciably decrease collection time	*/
219 			/* at the expense of space.			*/
220 			/* GC_free_space_divisor = 1 will effectively	*/
221 			/* disable collections.				*/
222 
223 GC_API GC_word GC_max_retries;
224 			/* The maximum number of GCs attempted before	*/
225 			/* reporting out of memory after heap		*/
226 			/* expansion fails.  Initially 0.		*/
227 
228 
229 GC_API char *GC_stackbottom;	/* Cool end of user stack.		*/
230 				/* May be set in the client prior to	*/
231 				/* calling any GC_ routines.  This	*/
232 				/* avoids some overhead, and 		*/
233 				/* potentially some signals that can 	*/
234 				/* confuse debuggers.  Otherwise the	*/
235 				/* collector attempts to set it 	*/
236 				/* automatically.			*/
237 				/* For multithreaded code, this is the	*/
238 				/* cold end of the stack for the	*/
239 				/* primordial thread.			*/
240 
241 GC_API int GC_dont_precollect;  /* Don't collect as part of 		*/
242 				/* initialization.  Should be set only	*/
243 				/* if the client wants a chance to	*/
244 				/* manually initialize the root set	*/
245 				/* before the first collection.		*/
246 				/* Interferes with blacklisting.	*/
247 				/* Wizards only.			*/
248 
249 GC_API unsigned long GC_time_limit;
250 				/* If incremental collection is enabled, */
251 				/* We try to terminate collections	 */
252 				/* after this many milliseconds.  Not a	 */
253 				/* hard time bound.  Setting this to 	 */
254 				/* GC_TIME_UNLIMITED will essentially	 */
255 				/* disable incremental collection while  */
256 				/* leaving generational collection	 */
257 				/* enabled.	 			 */
258 #	define GC_TIME_UNLIMITED 999999
259 				/* Setting GC_time_limit to this value	 */
260 				/* will disable the "pause time exceeded"*/
261 				/* tests.				 */
262 
263 /* Public procedures */
264 
265 /* Initialize the collector.  This is only required when using thread-local
266  * allocation, since unlike the regular allocation routines, GC_local_malloc
267  * is not self-initializing.  If you use GC_local_malloc you should arrange
268  * to call this somehow (e.g. from a constructor) before doing any allocation.
269  * For win32 threads, it needs to be called explicitly.
270  */
271 GC_API void GC_init GC_PROTO((void));
272 
273 /*
274  * general purpose allocation routines, with roughly malloc calling conv.
275  * The atomic versions promise that no relevant pointers are contained
276  * in the object.  The nonatomic versions guarantee that the new object
277  * is cleared.  GC_malloc_stubborn promises that no changes to the object
278  * will occur after GC_end_stubborn_change has been called on the
279  * result of GC_malloc_stubborn. GC_malloc_uncollectable allocates an object
280  * that is scanned for pointers to collectable objects, but is not itself
281  * collectable.  The object is scanned even if it does not appear to
282  * be reachable.  GC_malloc_uncollectable and GC_free called on the resulting
283  * object implicitly update GC_non_gc_bytes appropriately.
284  *
285  * Note that the GC_malloc_stubborn support is stubbed out by default
286  * starting in 6.0.  GC_malloc_stubborn is an alias for GC_malloc unless
287  * the collector is built with STUBBORN_ALLOC defined.
288  */
289 GC_API GC_PTR GC_malloc GC_PROTO((size_t size_in_bytes));
290 GC_API GC_PTR GC_malloc_atomic GC_PROTO((size_t size_in_bytes));
291 GC_API GC_PTR GC_malloc_uncollectable GC_PROTO((size_t size_in_bytes));
292 GC_API GC_PTR GC_malloc_stubborn GC_PROTO((size_t size_in_bytes));
293 
294 /* The following is only defined if the library has been suitably	*/
295 /* compiled:								*/
296 GC_API GC_PTR GC_malloc_atomic_uncollectable GC_PROTO((size_t size_in_bytes));
297 
298 /* Explicitly deallocate an object.  Dangerous if used incorrectly.     */
299 /* Requires a pointer to the base of an object.				*/
300 /* If the argument is stubborn, it should not be changeable when freed. */
301 /* An object should not be enable for finalization when it is 		*/
302 /* explicitly deallocated.						*/
303 /* GC_free(0) is a no-op, as required by ANSI C for free.		*/
304 GC_API void GC_free GC_PROTO((GC_PTR object_addr));
305 
306 /*
307  * Stubborn objects may be changed only if the collector is explicitly informed.
308  * The collector is implicitly informed of coming change when such
309  * an object is first allocated.  The following routines inform the
310  * collector that an object will no longer be changed, or that it will
311  * once again be changed.  Only nonNIL pointer stores into the object
312  * are considered to be changes.  The argument to GC_end_stubborn_change
313  * must be exacly the value returned by GC_malloc_stubborn or passed to
314  * GC_change_stubborn.  (In the second case it may be an interior pointer
315  * within 512 bytes of the beginning of the objects.)
316  * There is a performance penalty for allowing more than
317  * one stubborn object to be changed at once, but it is acceptable to
318  * do so.  The same applies to dropping stubborn objects that are still
319  * changeable.
320  */
321 GC_API void GC_change_stubborn GC_PROTO((GC_PTR));
322 GC_API void GC_end_stubborn_change GC_PROTO((GC_PTR));
323 
324 /* Return a pointer to the base (lowest address) of an object given	*/
325 /* a pointer to a location within the object.				*/
326 /* I.e. map an interior pointer to the corresponding bas pointer.	*/
327 /* Note that with debugging allocation, this returns a pointer to the	*/
328 /* actual base of the object, i.e. the debug information, not to	*/
329 /* the base of the user object.						*/
330 /* Return 0 if displaced_pointer doesn't point to within a valid	*/
331 /* object.								*/
332 /* Note that a deallocated object in the garbage collected heap		*/
333 /* may be considered valid, even if it has been deallocated with	*/
334 /* GC_free.  								*/
335 GC_API GC_PTR GC_base GC_PROTO((GC_PTR displaced_pointer));
336 
337 /* Given a pointer to the base of an object, return its size in bytes.	*/
338 /* The returned size may be slightly larger than what was originally	*/
339 /* requested.								*/
340 GC_API size_t GC_size GC_PROTO((GC_PTR object_addr));
341 
342 /* For compatibility with C library.  This is occasionally faster than	*/
343 /* a malloc followed by a bcopy.  But if you rely on that, either here	*/
344 /* or with the standard C library, your code is broken.  In my		*/
345 /* opinion, it shouldn't have been invented, but now we're stuck. -HB	*/
346 /* The resulting object has the same kind as the original.		*/
347 /* If the argument is stubborn, the result will have changes enabled.	*/
348 /* It is an error to have changes enabled for the original object.	*/
349 /* Follows ANSI comventions for NULL old_object.			*/
350 GC_API GC_PTR GC_realloc
351 	GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes));
352 
353 /* Explicitly increase the heap size.	*/
354 /* Returns 0 on failure, 1 on success.  */
355 GC_API int GC_expand_hp GC_PROTO((size_t number_of_bytes));
356 
357 /* Limit the heap size to n bytes.  Useful when you're debugging, 	*/
358 /* especially on systems that don't handle running out of memory well.	*/
359 /* n == 0 ==> unbounded.  This is the default.				*/
360 GC_API void GC_set_max_heap_size GC_PROTO((GC_word n));
361 
362 /* Inform the collector that a certain section of statically allocated	*/
363 /* memory contains no pointers to garbage collected memory.  Thus it 	*/
364 /* need not be scanned.  This is sometimes important if the application */
365 /* maps large read/write files into the address space, which could be	*/
366 /* mistaken for dynamic library data segments on some systems.		*/
367 GC_API void GC_exclude_static_roots GC_PROTO((GC_PTR start, GC_PTR finish));
368 
369 /* Clear the set of root segments.  Wizards only. */
370 GC_API void GC_clear_roots GC_PROTO((void));
371 
372 /* Add a root segment.  Wizards only. */
373 GC_API void GC_add_roots GC_PROTO((char * low_address,
374 				   char * high_address_plus_1));
375 
376 /* Remove a root segment.  Wizards only. */
377 GC_API void GC_remove_roots GC_PROTO((char * low_address,
378     char * high_address_plus_1));
379 
380 /* Add a displacement to the set of those considered valid by the	*/
381 /* collector.  GC_register_displacement(n) means that if p was returned */
382 /* by GC_malloc, then (char *)p + n will be considered to be a valid	*/
383 /* pointer to p.  N must be small and less than the size of p.		*/
384 /* (All pointers to the interior of objects from the stack are		*/
385 /* considered valid in any case.  This applies to heap objects and	*/
386 /* static data.)							*/
387 /* Preferably, this should be called before any other GC procedures.	*/
388 /* Calling it later adds to the probability of excess memory		*/
389 /* retention.								*/
390 /* This is a no-op if the collector has recognition of			*/
391 /* arbitrary interior pointers enabled, which is now the default.	*/
392 GC_API void GC_register_displacement GC_PROTO((GC_word n));
393 
394 /* The following version should be used if any debugging allocation is	*/
395 /* being done.								*/
396 GC_API void GC_debug_register_displacement GC_PROTO((GC_word n));
397 
398 /* Explicitly trigger a full, world-stop collection. 	*/
399 GC_API void GC_gcollect GC_PROTO((void));
400 
401 /* Trigger a full world-stopped collection.  Abort the collection if 	*/
402 /* and when stop_func returns a nonzero value.  Stop_func will be 	*/
403 /* called frequently, and should be reasonably fast.  This works even	*/
404 /* if virtual dirty bits, and hence incremental collection is not 	*/
405 /* available for this architecture.  Collections can be aborted faster	*/
406 /* than normal pause times for incremental collection.  However,	*/
407 /* aborted collections do no useful work; the next collection needs	*/
408 /* to start from the beginning.						*/
409 /* Return 0 if the collection was aborted, 1 if it succeeded.		*/
410 typedef int (* GC_stop_func) GC_PROTO((void));
411 GC_API int GC_try_to_collect GC_PROTO((GC_stop_func stop_func));
412 
413 /* Return the number of bytes in the heap.  Excludes collector private	*/
414 /* data structures.  Includes empty blocks and fragmentation loss.	*/
415 /* Includes some pages that were allocated but never written.		*/
416 GC_API size_t GC_get_heap_size GC_PROTO((void));
417 
418 /* Return a lower bound on the number of free bytes in the heap.	*/
419 GC_API size_t GC_get_free_bytes GC_PROTO((void));
420 
421 /* Return the number of bytes allocated since the last collection.	*/
422 GC_API size_t GC_get_bytes_since_gc GC_PROTO((void));
423 
424 /* Return the total number of bytes allocated in this process.		*/
425 /* Never decreases, except due to wrapping.				*/
426 GC_API size_t GC_get_total_bytes GC_PROTO((void));
427 
428 /* Return the signal used by the gc to suspend threads on posix platforms. */
429 /* Return -1 otherwise. */
430 int GC_get_suspend_signal GC_PROTO((void));
431 
432 /* Return the signal used by the gc to resume threads on posix platforms. */
433 /* Return -1 otherwise. */
434 int GC_get_thr_restart_signal GC_PROTO((void));
435 
436 /* Explicitly enable GC_register_my_thread() invocation.		*/
437 GC_API void GC_allow_register_threads GC_PROTO((void));
438 
439 /* Disable garbage collection.  Even GC_gcollect calls will be 		*/
440 /* ineffective.								*/
441 GC_API void GC_disable GC_PROTO((void));
442 
443 /* Reenable garbage collection.  GC_disable() and GC_enable() calls 	*/
444 /* nest.  Garbage collection is enabled if the number of calls to both	*/
445 /* both functions is equal.						*/
446 GC_API void GC_enable GC_PROTO((void));
447 
448 /* Enable incremental/generational collection.	*/
449 /* Not advisable unless dirty bits are 		*/
450 /* available or most heap objects are		*/
451 /* pointerfree(atomic) or immutable.		*/
452 /* Don't use in leak finding mode.		*/
453 /* Ignored if GC_dont_gc is true.		*/
454 /* Only the generational piece of this is	*/
455 /* functional if GC_parallel is TRUE		*/
456 /* or if GC_time_limit is GC_TIME_UNLIMITED.	*/
457 /* Causes GC_local_gcj_malloc() to revert to	*/
458 /* locked allocation.  Must be called 		*/
459 /* before any GC_local_gcj_malloc() calls.	*/
460 GC_API void GC_enable_incremental GC_PROTO((void));
461 
462 /* Does incremental mode write-protect pages?  Returns zero or	*/
463 /* more of the following, or'ed together:			*/
464 #define GC_PROTECTS_POINTER_HEAP  1 /* May protect non-atomic objs.	*/
465 #define GC_PROTECTS_PTRFREE_HEAP  2
466 #define GC_PROTECTS_STATIC_DATA   4 /* Curently never.			*/
467 #define GC_PROTECTS_STACK	  8 /* Probably impractical.		*/
468 
469 #define GC_PROTECTS_NONE 0
470 GC_API int GC_incremental_protection_needs GC_PROTO((void));
471 
472 /* Perform some garbage collection work, if appropriate.	*/
473 /* Return 0 if there is no more work to be done.		*/
474 /* Typically performs an amount of work corresponding roughly	*/
475 /* to marking from one page.  May do more work if further	*/
476 /* progress requires it, e.g. if incremental collection is	*/
477 /* disabled.  It is reasonable to call this in a wait loop	*/
478 /* until it returns 0.						*/
479 GC_API int GC_collect_a_little GC_PROTO((void));
480 
481 /* Allocate an object of size lb bytes.  The client guarantees that	*/
482 /* as long as the object is live, it will be referenced by a pointer	*/
483 /* that points to somewhere within the first 256 bytes of the object.	*/
484 /* (This should normally be declared volatile to prevent the compiler	*/
485 /* from invalidating this assertion.)  This routine is only useful	*/
486 /* if a large array is being allocated.  It reduces the chance of 	*/
487 /* accidentally retaining such an array as a result of scanning an	*/
488 /* integer that happens to be an address inside the array.  (Actually,	*/
489 /* it reduces the chance of the allocator not finding space for such	*/
490 /* an array, since it will try hard to avoid introducing such a false	*/
491 /* reference.)  On a SunOS 4.X or MS Windows system this is recommended */
492 /* for arrays likely to be larger than 100K or so.  For other systems,	*/
493 /* or if the collector is not configured to recognize all interior	*/
494 /* pointers, the threshold is normally much higher.			*/
495 GC_API GC_PTR GC_malloc_ignore_off_page GC_PROTO((size_t lb));
496 GC_API GC_PTR GC_malloc_atomic_ignore_off_page GC_PROTO((size_t lb));
497 
498 #if defined(__sgi) && !defined(__GNUC__) && _COMPILER_VERSION >= 720
499 #   define GC_ADD_CALLER
500 #   define GC_RETURN_ADDR (GC_word)__return_address
501 #endif
502 
503 #if defined(__linux__) || defined(__GLIBC__)
504 # include <features.h>
505 # if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1 || __GLIBC__ > 2) \
506      && !defined(__ia64__)
507 #   ifndef GC_HAVE_BUILTIN_BACKTRACE
508 #     define GC_HAVE_BUILTIN_BACKTRACE
509 #   endif
510 # endif
511 # if defined(__i386__) || defined(__x86_64__)
512 #   define GC_CAN_SAVE_CALL_STACKS
513 # endif
514 #endif
515 
516 #if defined(GC_HAVE_BUILTIN_BACKTRACE) && !defined(GC_CAN_SAVE_CALL_STACKS)
517 # define GC_CAN_SAVE_CALL_STACKS
518 #endif
519 
520 #if defined(__sparc__)
521 #   define GC_CAN_SAVE_CALL_STACKS
522 #endif
523 
524 /* If we're on an a platform on which we can't save call stacks, but	*/
525 /* gcc is normally used, we go ahead and define GC_ADD_CALLER.  	*/
526 /* We make this decision independent of whether gcc is actually being	*/
527 /* used, in order to keep the interface consistent, and allow mixing	*/
528 /* of compilers.							*/
529 /* This may also be desirable if it is possible but expensive to	*/
530 /* retrieve the call chain.						*/
531 #if (defined(__linux__) || defined(__NetBSD__) || defined(__OpenBSD__) \
532      || defined(__FreeBSD__)) & !defined(GC_CAN_SAVE_CALL_STACKS)
533 # define GC_ADD_CALLER
534 # if __GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95)
535     /* gcc knows how to retrieve return address, but we don't know */
536     /* how to generate call stacks.				   */
537 #   define GC_RETURN_ADDR (GC_word)__builtin_return_address(0)
538 # else
539     /* Just pass 0 for gcc compatibility. */
540 #   define GC_RETURN_ADDR 0
541 # endif
542 #endif
543 
544 #ifdef GC_ADD_CALLER
545 #  define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__
546 #  define GC_EXTRA_PARAMS GC_word ra, GC_CONST char * s, int i
547 #else
548 #  define GC_EXTRAS __FILE__, __LINE__
549 #  define GC_EXTRA_PARAMS GC_CONST char * s, int i
550 #endif
551 
552 /* Debugging (annotated) allocation.  GC_gcollect will check 		*/
553 /* objects allocated in this way for overwrites, etc.			*/
554 GC_API GC_PTR GC_debug_malloc
555 	GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
556 GC_API GC_PTR GC_debug_malloc_atomic
557 	GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
558 GC_API GC_PTR GC_debug_malloc_uncollectable
559 	GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
560 GC_API GC_PTR GC_debug_malloc_stubborn
561 	GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
562 GC_API GC_PTR GC_debug_malloc_ignore_off_page
563 	GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
564 GC_API GC_PTR GC_debug_malloc_atomic_ignore_off_page
565 	GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
566 GC_API void GC_debug_free GC_PROTO((GC_PTR object_addr));
567 GC_API GC_PTR GC_debug_realloc
568 	GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes,
569   		  GC_EXTRA_PARAMS));
570 GC_API void GC_debug_change_stubborn GC_PROTO((GC_PTR));
571 GC_API void GC_debug_end_stubborn_change GC_PROTO((GC_PTR));
572 
573 /* Routines that allocate objects with debug information (like the 	*/
574 /* above), but just fill in dummy file and line number information.	*/
575 /* Thus they can serve as drop-in malloc/realloc replacements.  This	*/
576 /* can be useful for two reasons:  					*/
577 /* 1) It allows the collector to be built with DBG_HDRS_ALL defined	*/
578 /*    even if some allocation calls come from 3rd party libraries	*/
579 /*    that can't be recompiled.						*/
580 /* 2) On some platforms, the file and line information is redundant,	*/
581 /*    since it can be reconstructed from a stack trace.  On such	*/
582 /*    platforms it may be more convenient not to recompile, e.g. for	*/
583 /*    leak detection.  This can be accomplished by instructing the	*/
584 /*    linker to replace malloc/realloc with these.			*/
585 GC_API GC_PTR GC_debug_malloc_replacement GC_PROTO((size_t size_in_bytes));
586 GC_API GC_PTR GC_debug_realloc_replacement
587 	      GC_PROTO((GC_PTR object_addr, size_t size_in_bytes));
588 
589 # ifdef GC_DEBUG
590 #   define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS)
591 #   define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS)
592 #   define GC_MALLOC_UNCOLLECTABLE(sz) \
593 			GC_debug_malloc_uncollectable(sz, GC_EXTRAS)
594 #   define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
595 			GC_debug_malloc_ignore_off_page(sz, GC_EXTRAS)
596 #   define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
597 			GC_debug_malloc_atomic_ignore_off_page(sz, GC_EXTRAS)
598 #   define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, GC_EXTRAS)
599 #   define GC_FREE(p) GC_debug_free(p)
600 #   define GC_REGISTER_FINALIZER(p, f, d, of, od) \
601 	GC_debug_register_finalizer(p, f, d, of, od)
602 #   define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
603 	GC_debug_register_finalizer_ignore_self(p, f, d, of, od)
604 #   define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
605 	GC_debug_register_finalizer_no_order(p, f, d, of, od)
606 #   define GC_MALLOC_STUBBORN(sz) GC_debug_malloc_stubborn(sz, GC_EXTRAS);
607 #   define GC_CHANGE_STUBBORN(p) GC_debug_change_stubborn(p)
608 #   define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
609 #   define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
610 	GC_general_register_disappearing_link(link, GC_base(obj))
611 #   define GC_REGISTER_LONG_LINK(link, obj) \
612 	GC_register_long_link(link, GC_base(obj))
613 #   define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
614 # else
615 #   define GC_MALLOC(sz) GC_malloc(sz)
616 #   define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
617 #   define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz)
618 #   define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
619 			GC_malloc_ignore_off_page(sz)
620 #   define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
621 			GC_malloc_atomic_ignore_off_page(sz)
622 #   define GC_REALLOC(old, sz) GC_realloc(old, sz)
623 #   define GC_FREE(p) GC_free(p)
624 #   define GC_REGISTER_FINALIZER(p, f, d, of, od) \
625 	GC_register_finalizer(p, f, d, of, od)
626 #   define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
627 	GC_register_finalizer_ignore_self(p, f, d, of, od)
628 #   define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
629 	GC_register_finalizer_no_order(p, f, d, of, od)
630 #   define GC_MALLOC_STUBBORN(sz) GC_malloc_stubborn(sz)
631 #   define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p)
632 #   define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
633 #   define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
634 	GC_general_register_disappearing_link(link, obj)
635 #   define GC_REGISTER_LONG_LINK(link, obj) \
636 	GC_register_long_link(link, obj)
637 #   define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
638 # endif
639 /* The following are included because they are often convenient, and	*/
640 /* reduce the chance for a misspecifed size argument.  But calls may	*/
641 /* expand to something syntactically incorrect if t is a complicated	*/
642 /* type expression.  							*/
643 # define GC_NEW(t) (t *)GC_MALLOC(sizeof (t))
644 # define GC_NEW_ATOMIC(t) (t *)GC_MALLOC_ATOMIC(sizeof (t))
645 # define GC_NEW_STUBBORN(t) (t *)GC_MALLOC_STUBBORN(sizeof (t))
646 # define GC_NEW_UNCOLLECTABLE(t) (t *)GC_MALLOC_UNCOLLECTABLE(sizeof (t))
647 
648 /* Finalization.  Some of these primitives are grossly unsafe.		*/
649 /* The idea is to make them both cheap, and sufficient to build		*/
650 /* a safer layer, closer to Modula-3, Java, or PCedar finalization.	*/
651 /* The interface represents my conclusions from a long discussion	*/
652 /* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes, 		*/
653 /* Christian Jacobi, and Russ Atkinson.  It's not perfect, and		*/
654 /* probably nobody else agrees with it.	    Hans-J. Boehm  3/13/92	*/
655 typedef void (*GC_finalization_proc)
656   	GC_PROTO((GC_PTR obj, GC_PTR client_data));
657 
658 GC_API void GC_register_finalizer
659     	GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
660 		  GC_finalization_proc *ofn, GC_PTR *ocd));
661 GC_API void GC_debug_register_finalizer
662     	GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
663 		  GC_finalization_proc *ofn, GC_PTR *ocd));
664 	/* When obj is no longer accessible, invoke		*/
665 	/* (*fn)(obj, cd).  If a and b are inaccessible, and	*/
666 	/* a points to b (after disappearing links have been	*/
667 	/* made to disappear), then only a will be		*/
668 	/* finalized.  (If this does not create any new		*/
669 	/* pointers to b, then b will be finalized after the	*/
670 	/* next collection.)  Any finalizable object that	*/
671 	/* is reachable from itself by following one or more	*/
672 	/* pointers will not be finalized (or collected).	*/
673 	/* Thus cycles involving finalizable objects should	*/
674 	/* be avoided, or broken by disappearing links.		*/
675 	/* All but the last finalizer registered for an object  */
676 	/* is ignored.						*/
677 	/* Finalization may be removed by passing 0 as fn.	*/
678 	/* Finalizers are implicitly unregistered just before   */
679 	/* they are invoked.					*/
680 	/* The old finalizer and client data are stored in	*/
681 	/* *ofn and *ocd.					*/
682 	/* Fn is never invoked on an accessible object,		*/
683 	/* provided hidden pointers are converted to real 	*/
684 	/* pointers only if the allocation lock is held, and	*/
685 	/* such conversions are not performed by finalization	*/
686 	/* routines.						*/
687 	/* If GC_register_finalizer is aborted as a result of	*/
688 	/* a signal, the object may be left with no		*/
689 	/* finalization, even if neither the old nor new	*/
690 	/* finalizer were NULL.					*/
691 	/* Obj should be the nonNULL starting address of an 	*/
692 	/* object allocated by GC_malloc or friends.		*/
693 	/* Note that any garbage collectable object referenced	*/
694 	/* by cd will be considered accessible until the	*/
695 	/* finalizer is invoked.				*/
696 
697 /* Another versions of the above follow.  It ignores		*/
698 /* self-cycles, i.e. pointers from a finalizable object to	*/
699 /* itself.  There is a stylistic argument that this is wrong,	*/
700 /* but it's unavoidable for C++, since the compiler may		*/
701 /* silently introduce these.  It's also benign in that specific	*/
702 /* case.  And it helps if finalizable objects are split to	*/
703 /* avoid cycles.						*/
704 /* Note that cd will still be viewed as accessible, even if it	*/
705 /* refers to the object itself.					*/
706 GC_API void GC_register_finalizer_ignore_self
707 	GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
708 		  GC_finalization_proc *ofn, GC_PTR *ocd));
709 GC_API void GC_debug_register_finalizer_ignore_self
710 	GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
711 		  GC_finalization_proc *ofn, GC_PTR *ocd));
712 
713 /* Another version of the above.  It ignores all cycles.        */
714 /* It should probably only be used by Java implementations.     */
715 /* Note that cd will still be viewed as accessible, even if it	*/
716 /* refers to the object itself.					*/
717 GC_API void GC_register_finalizer_no_order
718 	GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
719 		  GC_finalization_proc *ofn, GC_PTR *ocd));
720 GC_API void GC_debug_register_finalizer_no_order
721 	GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
722 		  GC_finalization_proc *ofn, GC_PTR *ocd));
723 
724 
725 /* The following routine may be used to break cycles between	*/
726 /* finalizable objects, thus causing cyclic finalizable		*/
727 /* objects to be finalized in the correct order.  Standard	*/
728 /* use involves calling GC_register_disappearing_link(&p),	*/
729 /* where p is a pointer that is not followed by finalization	*/
730 /* code, and should not be considered in determining 		*/
731 /* finalization order.						*/
732 GC_API int GC_register_disappearing_link GC_PROTO((GC_PTR * /* link */));
733 	/* Link should point to a field of a heap allocated 	*/
734 	/* object obj.  *link will be cleared when obj is	*/
735 	/* found to be inaccessible.  This happens BEFORE any	*/
736 	/* finalization code is invoked, and BEFORE any		*/
737 	/* decisions about finalization order are made.		*/
738 	/* This is useful in telling the finalizer that 	*/
739 	/* some pointers are not essential for proper		*/
740 	/* finalization.  This may avoid finalization cycles.	*/
741 	/* Note that obj may be resurrected by another		*/
742 	/* finalizer, and thus the clearing of *link may	*/
743 	/* be visible to non-finalization code.  		*/
744 	/* There's an argument that an arbitrary action should  */
745 	/* be allowed here, instead of just clearing a pointer. */
746 	/* But this causes problems if that action alters, or 	*/
747 	/* examines connectivity.				*/
748 	/* Returns 1 if link was already registered, 0		*/
749 	/* otherwise.						*/
750 	/* Only exists for backward compatibility.  See below:	*/
751 
752 GC_API int GC_general_register_disappearing_link
753 	GC_PROTO((GC_PTR * /* link */, GC_PTR obj));
754 	/* A slight generalization of the above. *link is	*/
755 	/* cleared when obj first becomes inaccessible.  This	*/
756 	/* can be used to implement weak pointers easily and	*/
757 	/* safely. Typically link will point to a location	*/
758 	/* holding a disguised pointer to obj.  (A pointer 	*/
759 	/* inside an "atomic" object is effectively  		*/
760 	/* disguised.)   In this way soft			*/
761 	/* pointers are broken before any object		*/
762 	/* reachable from them are finalized.  Each link	*/
763 	/* May be registered only once, i.e. with one obj	*/
764 	/* value.  This was added after a long email discussion */
765 	/* with John Ellis.					*/
766 	/* Obj must be a pointer to the first word of an object */
767 	/* we allocated.  It is unsafe to explicitly deallocate */
768 	/* the object containing link.  Explicitly deallocating */
769 	/* obj may or may not cause link to eventually be	*/
770 	/* cleared.						*/
771 GC_API int GC_unregister_disappearing_link GC_PROTO((GC_PTR * /* link */));
772 	/* Returns 0 if link was not actually registered.	*/
773 	/* Undoes a registration by either of the above two	*/
774 	/* routines.						*/
775 
776 GC_API int GC_register_long_link GC_PROTO((GC_PTR * /* link */, GC_PTR obj));
777 GC_API int GC_unregister_long_link GC_PROTO((GC_PTR * /* link */));
778 
779 typedef enum {
780 	GC_TOGGLE_REF_DROP,
781 	GC_TOGGLE_REF_STRONG,
782 	GC_TOGGLE_REF_WEAK
783 } GC_ToggleRefStatus;
784 
785 /* toggleref support */
786 GC_API void GC_set_toggleref_func GC_PROTO(
787 		(GC_ToggleRefStatus (*proccess_toggleref) (GC_PTR obj)));
788 GC_API int GC_toggleref_add (GC_PTR object, int strong_ref);
789 	/* Returns GC_SUCCESS if registration succeeded (or no callback	*/
790 	/* registered yet), GC_NO_MEMORY if failed for lack of memory.	*/
791 
792 /* finalizer callback support */
793 GC_API void GC_set_await_finalize_proc GC_PROTO((void (*object_finalized) (GC_PTR obj)));
794 
795 
796 /* Returns !=0  if GC_invoke_finalizers has something to do. 		*/
797 GC_API int GC_should_invoke_finalizers GC_PROTO((void));
798 
799 GC_API int GC_invoke_finalizers GC_PROTO((void));
800 	/* Run finalizers for all objects that are ready to	*/
801 	/* be finalized.  Return the number of finalizers	*/
802 	/* that were run.  Normally this is also called		*/
803 	/* implicitly during some allocations.	If		*/
804 	/* GC-finalize_on_demand is nonzero, it must be called	*/
805 	/* explicitly.						*/
806 
807 /* GC_set_warn_proc can be used to redirect or filter warning messages.	*/
808 /* p may not be a NULL pointer.						*/
809 typedef void (*GC_warn_proc) GC_PROTO((char *msg, GC_word arg));
810 GC_API GC_warn_proc GC_set_warn_proc GC_PROTO((GC_warn_proc p));
811     /* Returns old warning procedure.	*/
812 
813 GC_API GC_word GC_set_free_space_divisor GC_PROTO((GC_word value));
814     /* Set free_space_divisor.  See above for definition.	*/
815     /* Returns old value.					*/
816 
817 /* The following is intended to be used by a higher level	*/
818 /* (e.g. Java-like) finalization facility.  It is expected	*/
819 /* that finalization code will arrange for hidden pointers to	*/
820 /* disappear.  Otherwise objects can be accessed after they	*/
821 /* have been collected.						*/
822 /* Note that putting pointers in atomic objects or in 		*/
823 /* nonpointer slots of "typed" objects is equivalent to 	*/
824 /* disguising them in this way, and may have other advantages.	*/
825 # if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
826     typedef GC_word GC_hidden_pointer;
827 #   define HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
828 #   define REVEAL_POINTER(p) ((GC_PTR)(HIDE_POINTER(p)))
829     /* Converting a hidden pointer to a real pointer requires verifying	*/
830     /* that the object still exists.  This involves acquiring the  	*/
831     /* allocator lock to avoid a race with the collector.		*/
832 # endif /* I_HIDE_POINTERS */
833 
834 typedef GC_PTR (*GC_fn_type) GC_PROTO((GC_PTR client_data));
835 GC_API GC_PTR GC_call_with_alloc_lock
836         	GC_PROTO((GC_fn_type fn, GC_PTR client_data));
837 
838 /* The following routines are primarily intended for use with a 	*/
839 /* preprocessor which inserts calls to check C pointer arithmetic.	*/
840 /* They indicate failure by invoking the corresponding _print_proc.	*/
841 
842 /* Check that p and q point to the same object.  		*/
843 /* Fail conspicuously if they don't.				*/
844 /* Returns the first argument.  				*/
845 /* Succeeds if neither p nor q points to the heap.		*/
846 /* May succeed if both p and q point to between heap objects.	*/
847 GC_API GC_PTR GC_same_obj GC_PROTO((GC_PTR p, GC_PTR q));
848 
849 /* Checked pointer pre- and post- increment operations.  Note that	*/
850 /* the second argument is in units of bytes, not multiples of the	*/
851 /* object size.  This should either be invoked from a macro, or the	*/
852 /* call should be automatically generated.				*/
853 GC_API GC_PTR GC_pre_incr GC_PROTO((GC_PTR *p, size_t how_much));
854 GC_API GC_PTR GC_post_incr GC_PROTO((GC_PTR *p, size_t how_much));
855 
856 /* Check that p is visible						*/
857 /* to the collector as a possibly pointer containing location.		*/
858 /* If it isn't fail conspicuously.					*/
859 /* Returns the argument in all cases.  May erroneously succeed		*/
860 /* in hard cases.  (This is intended for debugging use with		*/
861 /* untyped allocations.  The idea is that it should be possible, though	*/
862 /* slow, to add such a call to all indirect pointer stores.)		*/
863 /* Currently useless for multithreaded worlds.				*/
864 GC_API GC_PTR GC_is_visible GC_PROTO((GC_PTR p));
865 
866 /* Check that if p is a pointer to a heap page, then it points to	*/
867 /* a valid displacement within a heap object.				*/
868 /* Fail conspicuously if this property does not hold.			*/
869 /* Uninteresting with GC_all_interior_pointers.				*/
870 /* Always returns its argument.						*/
871 GC_API GC_PTR GC_is_valid_displacement GC_PROTO((GC_PTR	p));
872 
873 #define GC_SUCCESS 0
874 #define GC_DUPLICATE 1		/* Was already registered.		*/
875 #define GC_NO_MEMORY 2		/* Failure due to lack of memory.	*/
876 #define GC_UNIMPLEMENTED 3	/* Not yet implemented on the platform.	*/
877 
878 /* Structure representing the base of a thread stack.			*/
879 struct GC_stack_base {
880 	void * mem_base; /* Base of memory stack. */
881 };
882 
883 /* Register the current thread, with the indicated stack base.		*/
884 /* Returns GC_SUCCESS on success, GC_DUPLICATE if already registered.	*/
885 /* On some platforms it returns GC_UNIMPLEMENTED.			*/
886 GC_API int GC_register_my_thread GC_PROTO((struct GC_stack_base *));
887 
888 /* Returns 1 if the calling thread is registered with the GC, 0 otherwise */
889 GC_API int GC_thread_is_registered GC_PROTO((void));
890 
891 /* Notify the collector about the stack and the altstack of the current thread */
892 /* STACK/STACK_SIZE is used to determine the stack dimensions when a thread is
893  * suspended while it is on an altstack.
894  */
895 GC_API void GC_register_altstack GC_PROTO((void *stack, int stack_size, void *altstack, int altstack_size));
896 
897 /* Safer, but slow, pointer addition.  Probably useful mainly with 	*/
898 /* a preprocessor.  Useful only for heap pointers.			*/
899 #ifdef GC_DEBUG
900 #   define GC_PTR_ADD3(x, n, type_of_result) \
901 	((type_of_result)GC_same_obj((x)+(n), (x)))
902 #   define GC_PRE_INCR3(x, n, type_of_result) \
903 	((type_of_result)GC_pre_incr(&(x), (n)*sizeof(*x))
904 #   define GC_POST_INCR2(x, type_of_result) \
905 	((type_of_result)GC_post_incr(&(x), sizeof(*x))
906 #   ifdef __GNUC__
907 #       define GC_PTR_ADD(x, n) \
908 	    GC_PTR_ADD3(x, n, typeof(x))
909 #       define GC_PRE_INCR(x, n) \
910 	    GC_PRE_INCR3(x, n, typeof(x))
911 #       define GC_POST_INCR(x, n) \
912 	    GC_POST_INCR3(x, typeof(x))
913 #   else
914 	/* We can't do this right without typeof, which ANSI	*/
915 	/* decided was not sufficiently useful.  Repeatedly	*/
916 	/* mentioning the arguments seems too dangerous to be	*/
917 	/* useful.  So does not casting the result.		*/
918 #   	define GC_PTR_ADD(x, n) ((x)+(n))
919 #   endif
920 #else	/* !GC_DEBUG */
921 #   define GC_PTR_ADD3(x, n, type_of_result) ((x)+(n))
922 #   define GC_PTR_ADD(x, n) ((x)+(n))
923 #   define GC_PRE_INCR3(x, n, type_of_result) ((x) += (n))
924 #   define GC_PRE_INCR(x, n) ((x) += (n))
925 #   define GC_POST_INCR2(x, n, type_of_result) ((x)++)
926 #   define GC_POST_INCR(x, n) ((x)++)
927 #endif
928 
929 /* Safer assignment of a pointer to a nonstack location.	*/
930 #ifdef GC_DEBUG
931 # if defined(__STDC__) || defined(_AIX)
932 #   define GC_PTR_STORE(p, q) \
933 	(*(void **)GC_is_visible(p) = GC_is_valid_displacement(q))
934 # else
935 #   define GC_PTR_STORE(p, q) \
936 	(*(char **)GC_is_visible(p) = GC_is_valid_displacement(q))
937 # endif
938 #else /* !GC_DEBUG */
939 #   define GC_PTR_STORE(p, q) *((p) = (q))
940 #endif
941 
942 /* Functions called to report pointer checking errors */
943 GC_API void (*GC_same_obj_print_proc) GC_PROTO((GC_PTR p, GC_PTR q));
944 
945 GC_API void (*GC_is_valid_displacement_print_proc)
946 	GC_PROTO((GC_PTR p));
947 
948 GC_API void (*GC_is_visible_print_proc)
949 	GC_PROTO((GC_PTR p));
950 
951 /* For pthread support, we generally need to intercept a number of 	*/
952 /* thread library calls.  We do that here by macro defining them.	*/
953 
954 #if !defined(GC_USE_LD_WRAP) && \
955     (defined(GC_PTHREADS) || defined(GC_SOLARIS_THREADS) || defined(GC_DARWIN_THREADS) || defined(GC_MACOSX_THREADS))
956 # include "gc_pthread_redirects.h"
957 #endif
958 
959 # if defined(PCR) || defined(GC_SOLARIS_THREADS) || \
960      defined(GC_PTHREADS) || defined(GC_WIN32_THREADS)
961    	/* Any flavor of threads except SRC_M3.	*/
962 /* This returns a list of objects, linked through their first		*/
963 /* word.  Its use can greatly reduce lock contention problems, since	*/
964 /* the allocation lock can be acquired and released many fewer times.	*/
965 /* lb must be large enough to hold the pointer field.			*/
966 /* It is used internally by gc_local_alloc.h, which provides a simpler	*/
967 /* programming interface on Linux.					*/
968 GC_PTR GC_malloc_many(size_t lb);
969 #define GC_NEXT(p) (*(GC_PTR *)(p)) 	/* Retrieve the next element	*/
970 					/* in returned list.		*/
971 extern void GC_thr_init(void);	/* Needed for Solaris/X86	*/
972 
973 #endif /* THREADS && !SRC_M3 */
974 
975 #if defined(GC_WIN32_THREADS) && !defined(__CYGWIN32__) && !defined(__CYGWIN__)
976 # include <windows.h>
977 
978 # ifdef GC_INSIDE_DLL
979    BOOL WINAPI GC_DllMain(HINSTANCE inst, ULONG reason, LPVOID reserved);
980 # endif
981 
982   /*
983    * All threads must be created using GC_CreateThread, so that they will be
984    * recorded in the thread table.  For backwards compatibility, this is not
985    * technically true if the GC is built as a dynamic library, since it can
986    * and does then use DllMain to keep track of thread creations.  But new code
987    * should be built to call GC_CreateThread.
988    */
989    GC_API HANDLE WINAPI GC_CreateThread(
990       LPSECURITY_ATTRIBUTES lpThreadAttributes,
991       DWORD dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress,
992       LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId );
993 
994 # if defined(_WIN32_WCE)
995   /*
996    * win32_threads.c implements the real WinMain, which will start a new thread
997    * to call GC_WinMain after initializing the garbage collector.
998    */
999   int WINAPI GC_WinMain(
1000       HINSTANCE hInstance,
1001       HINSTANCE hPrevInstance,
1002       LPWSTR lpCmdLine,
1003       int nCmdShow );
1004 
1005 #  ifndef GC_BUILD
1006 #    define WinMain GC_WinMain
1007 #    define CreateThread GC_CreateThread
1008 #  endif
1009 # endif /* defined(_WIN32_WCE) */
1010 
1011 #endif /* defined(GC_WIN32_THREADS)  && !cygwin */
1012 
1013  /*
1014   * Fully portable code should call GC_INIT() from the main program
1015   * before making any other GC_ calls.  On most platforms this is a
1016   * no-op and the collector self-initializes.  But a number of platforms
1017   * make that too hard.
1018   */
1019 #if (defined(sparc) || defined(__sparc)) && defined(sun)
1020     /*
1021      * If you are planning on putting
1022      * the collector in a SunOS 5 dynamic library, you need to call GC_INIT()
1023      * from the statically loaded program section.
1024      * This circumvents a Solaris 2.X (X<=4) linker bug.
1025      */
1026 #   define GC_INIT() { extern end, etext; \
1027 		       GC_noop(&end, &etext); }
1028 #else
1029 # if defined(__CYGWIN32__) || defined (_AIX)
1030     /*
1031      * Similarly gnu-win32 DLLs need explicit initialization from
1032      * the main program, as does AIX.
1033      */
1034 #   ifdef __CYGWIN32__
1035       extern int _data_start__[];
1036       extern int _data_end__[];
1037       extern int _bss_start__[];
1038       extern int _bss_end__[];
1039 #     define GC_MAX(x,y) ((x) > (y) ? (x) : (y))
1040 #     define GC_MIN(x,y) ((x) < (y) ? (x) : (y))
1041 #     define GC_DATASTART ((GC_PTR) GC_MIN(_data_start__, _bss_start__))
1042 #     define GC_DATAEND	 ((GC_PTR) GC_MAX(_data_end__, _bss_end__))
1043 #     ifdef GC_DLL
1044 #       define GC_INIT() { GC_add_roots(GC_DATASTART, GC_DATAEND); }
1045 #     else
1046 #       define GC_INIT()
1047 #     endif
1048 #   endif
1049 #   if defined(_AIX)
1050       extern int _data[], _end[];
1051 #     define GC_DATASTART ((GC_PTR)((ulong)_data))
1052 #     define GC_DATAEND ((GC_PTR)((ulong)_end))
1053 #     define GC_INIT() { GC_add_roots(GC_DATASTART, GC_DATAEND); }
1054 #   endif
1055 # else
1056 #  if defined(__APPLE__) && defined(__MACH__) || defined(GC_WIN32_THREADS)
1057 #   define GC_INIT() { GC_init(); }
1058 #  else
1059 #   define GC_INIT()
1060 #  endif /* !__MACH && !GC_WIN32_THREADS */
1061 # endif /* !AIX && !cygwin */
1062 #endif /* !sparc */
1063 
1064 #if !defined(_WIN32_WCE) \
1065     && ((defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \
1066         || defined(_WIN32) && !defined(__CYGWIN32__) && !defined(__CYGWIN__))
1067   /* win32S may not free all resources on process exit.  */
1068   /* This explicitly deallocates the heap.		 */
1069     GC_API void GC_win32_free_heap ();
1070 #endif
1071 
1072 #if ( defined(_AMIGA) && !defined(GC_AMIGA_MAKINGLIB) )
1073   /* Allocation really goes through GC_amiga_allocwrapper_do */
1074 # include "gc_amiga_redirects.h"
1075 #endif
1076 
1077 #if defined(GC_REDIRECT_TO_LOCAL) && !defined(GC_LOCAL_ALLOC_H)
1078 #  include  "gc_local_alloc.h"
1079 #endif
1080 
1081 #ifdef __cplusplus
1082     }  /* end of extern "C" */
1083 #endif
1084 
1085 #endif /* _GC_H */
1086