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/libs/headers/gc/gc.h

http://github.com/nddrylliog/ooc
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   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 * Copyright (C) 2007 Free Software Foundation, Inc
   7 *
   8 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   9 * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
  10 *
  11 * Permission is hereby granted to use or copy this program
  12 * for any purpose,  provided the above notices are retained on all copies.
  13 * Permission to modify the code and to distribute modified code is granted,
  14 * provided the above notices are retained, and a notice that the code was
  15 * modified is included with the above copyright notice.
  16 */
  17
  18/*
  19 * Note that this defines a large number of tuning hooks, which can
  20 * safely be ignored in nearly all cases.  For normal use it suffices
  21 * to call only GC_MALLOC and perhaps GC_REALLOC.
  22 * For better performance, also look at GC_MALLOC_ATOMIC, and
  23 * GC_enable_incremental.  If you need an action to be performed
  24 * immediately before an object is collected, look at GC_register_finalizer.
  25 * If you are using Solaris threads, look at the end of this file.
  26 * Everything else is best ignored unless you encounter performance
  27 * problems.
  28 */
  29 
  30#ifndef _GC_H
  31
  32# define _GC_H
  33
  34# include "gc_version.h"
  35	/* Define version numbers here to allow test on build machine	*/
  36	/* for cross-builds.  Note that this defines the header		*/
  37	/* version number, which may or may not match that of the	*/
  38	/* dynamic library.  The GC_version variable can be used	*/
  39	/* to obtain the latter.					*/
  40
  41# include "gc_config_macros.h"
  42
  43# ifdef __cplusplus
  44    extern "C" {
  45# endif
  46
  47
  48/* Define word and signed_word to be unsigned and signed types of the 	*/
  49/* size as char * or void *.  There seems to be no way to do this	*/
  50/* even semi-portably.  The following is probably no better/worse 	*/
  51/* than almost anything else.						*/
  52/* The ANSI standard suggests that size_t and ptr_diff_t might be 	*/
  53/* better choices.  But those had incorrect definitions on some older	*/
  54/* systems.  Notably "typedef int size_t" is WRONG.			*/
  55#ifndef _WIN64
  56  typedef unsigned long GC_word;
  57  typedef long GC_signed_word;
  58#else
  59  /* Win64 isn't really supported yet, but this is the first step. And	*/
  60  /* it might cause error messages to show up in more plausible places.	*/
  61  /* This needs basetsd.h, which is included by windows.h.	 	*/
  62  typedef unsigned long long GC_word;
  63  typedef long long GC_signed_word;
  64#endif
  65
  66/* Public read-only variables */
  67
  68GC_API GC_word GC_gc_no;/* Counter incremented per collection.  	*/
  69			/* Includes empty GCs at startup.		*/
  70
  71GC_API int GC_parallel;	/* GC is parallelized for performance on	*/
  72			/* multiprocessors.  Currently set only		*/
  73			/* implicitly if collector is built with	*/
  74			/* -DPARALLEL_MARK and if either:		*/
  75			/*  Env variable GC_NPROC is set to > 1, or	*/
  76			/*  GC_NPROC is not set and this is an MP.	*/
  77			/* If GC_parallel is set, incremental		*/
  78			/* collection is only partially functional,	*/
  79			/* and may not be desirable.			*/
  80			
  81
  82/* Public R/W variables */
  83
  84GC_API void * (*GC_oom_fn) (size_t bytes_requested);
  85			/* When there is insufficient memory to satisfy */
  86			/* an allocation request, we return		*/
  87			/* (*GC_oom_fn)().  By default this just	*/
  88			/* returns 0.					*/
  89			/* If it returns, it must return 0 or a valid	*/
  90			/* pointer to a previously allocated heap 	*/
  91			/* object.					*/
  92
  93GC_API int GC_find_leak;
  94			/* Do not actually garbage collect, but simply	*/
  95			/* report inaccessible memory that was not	*/
  96			/* deallocated with GC_free.  Initial value	*/
  97			/* is determined by FIND_LEAK macro.		*/
  98
  99GC_API int GC_all_interior_pointers;
 100			/* Arrange for pointers to object interiors to	*/
 101			/* be recognized as valid.  May not be changed	*/
 102			/* after GC initialization.			*/
 103			/* Initial value is determined by 		*/
 104			/* -DALL_INTERIOR_POINTERS.			*/
 105			/* Unless DONT_ADD_BYTE_AT_END is defined, this	*/
 106			/* also affects whether sizes are increased by	*/
 107			/* at least a byte to allow "off the end"	*/
 108			/* pointer recognition.				*/
 109			/* MUST BE 0 or 1.				*/
 110
 111GC_API int GC_finalize_on_demand;
 112			/* If nonzero, finalizers will only be run in 	*/
 113			/* response to an explicit GC_invoke_finalizers	*/
 114			/* call.  The default is determined by whether	*/
 115			/* the FINALIZE_ON_DEMAND macro is defined	*/
 116			/* when the collector is built.			*/
 117
 118GC_API int GC_java_finalization;
 119			/* Mark objects reachable from finalizable 	*/
 120			/* objects in a separate postpass.  This makes	*/
 121			/* it a bit safer to use non-topologically-	*/
 122			/* ordered finalization.  Default value is	*/
 123			/* determined by JAVA_FINALIZATION macro.	*/
 124			/* Enables register_finalizer_unreachable to	*/
 125			/* work correctly.				*/
 126
 127GC_API void (* GC_finalizer_notifier)(void);
 128			/* Invoked by the collector when there are 	*/
 129			/* objects to be finalized.  Invoked at most	*/
 130			/* once per GC cycle.  Never invoked unless 	*/
 131			/* GC_finalize_on_demand is set.		*/
 132			/* Typically this will notify a finalization	*/
 133			/* thread, which will call GC_invoke_finalizers */
 134			/* in response.					*/
 135
 136GC_API int GC_dont_gc;	/* != 0 ==> Dont collect.  In versions 6.2a1+,	*/
 137			/* this overrides explicit GC_gcollect() calls.	*/
 138			/* Used as a counter, so that nested enabling	*/
 139			/* and disabling work correctly.  Should	*/
 140			/* normally be updated with GC_enable() and	*/
 141			/* GC_disable() calls.				*/
 142			/* Direct assignment to GC_dont_gc is 		*/
 143			/* deprecated.					*/
 144
 145GC_API int GC_dont_expand;
 146			/* Dont expand heap unless explicitly requested */
 147			/* or forced to.				*/
 148
 149GC_API int GC_use_entire_heap;
 150		/* Causes the nonincremental collector to use the	*/
 151		/* entire heap before collecting.  This was the only 	*/
 152		/* option for GC versions < 5.0.  This sometimes	*/
 153		/* results in more large block fragmentation, since	*/
 154		/* very larg blocks will tend to get broken up		*/
 155		/* during each GC cycle.  It is likely to result in a	*/
 156		/* larger working set, but lower collection		*/
 157		/* frequencies, and hence fewer instructions executed	*/
 158		/* in the collector.					*/
 159
 160GC_API int GC_full_freq;    /* Number of partial collections between	*/
 161			    /* full collections.  Matters only if	*/
 162			    /* GC_incremental is set.			*/
 163			    /* Full collections are also triggered if	*/
 164			    /* the collector detects a substantial	*/
 165			    /* increase in the number of in-use heap	*/
 166			    /* blocks.  Values in the tens are now	*/
 167			    /* perfectly reasonable, unlike for		*/
 168			    /* earlier GC versions.			*/
 169			
 170GC_API GC_word GC_non_gc_bytes;
 171			/* Bytes not considered candidates for collection. */
 172			/* Used only to control scheduling of collections. */
 173			/* Updated by GC_malloc_uncollectable and GC_free. */
 174			/* Wizards only.				   */
 175
 176GC_API int GC_no_dls;
 177			/* Don't register dynamic library data segments. */
 178			/* Wizards only.  Should be used only if the	 */
 179			/* application explicitly registers all roots.	 */
 180			/* In Microsoft Windows environments, this will	 */
 181			/* usually also prevent registration of the	 */
 182			/* main data segment as part of the root set.	 */
 183
 184GC_API GC_word GC_free_space_divisor;
 185			/* We try to make sure that we allocate at 	*/
 186			/* least N/GC_free_space_divisor bytes between	*/
 187			/* collections, where N is twice the number	*/
 188			/* of traced bytes, plus the number of untraced */
 189			/* bytes (bytes in "atomic" objects), plus	*/
 190			/* a rough estimate of the root set size.	*/
 191			/* N approximates GC tracing work per GC.	*/
 192			/* Initially, GC_free_space_divisor = 3.	*/
 193			/* Increasing its value will use less space	*/
 194			/* but more collection time.  Decreasing it	*/
 195			/* will appreciably decrease collection time	*/
 196			/* at the expense of space.			*/
 197
 198GC_API GC_word GC_max_retries;
 199			/* The maximum number of GCs attempted before	*/
 200			/* reporting out of memory after heap		*/
 201			/* expansion fails.  Initially 0.		*/
 202			
 203
 204GC_API char *GC_stackbottom;    /* Cool end of user stack.		*/
 205				/* May be set in the client prior to	*/
 206				/* calling any GC_ routines.  This	*/
 207				/* avoids some overhead, and 		*/
 208				/* potentially some signals that can 	*/
 209				/* confuse debuggers.  Otherwise the	*/
 210				/* collector attempts to set it 	*/
 211				/* automatically.			*/
 212				/* For multithreaded code, this is the	*/
 213				/* cold end of the stack for the	*/
 214				/* primordial thread.			*/	
 215				
 216GC_API int GC_dont_precollect;  /* Don't collect as part of 		*/
 217				/* initialization.  Should be set only	*/
 218				/* if the client wants a chance to	*/
 219				/* manually initialize the root set	*/
 220				/* before the first collection.		*/
 221				/* Interferes with blacklisting.	*/
 222				/* Wizards only.			*/
 223
 224GC_API unsigned long GC_time_limit;
 225				/* If incremental collection is enabled, */
 226				/* We try to terminate collections	 */
 227				/* after this many milliseconds.  Not a	 */
 228				/* hard time bound.  Setting this to 	 */
 229				/* GC_TIME_UNLIMITED will essentially	 */
 230				/* disable incremental collection while  */
 231				/* leaving generational collection	 */
 232				/* enabled.	 			 */
 233#	define GC_TIME_UNLIMITED 999999
 234				/* Setting GC_time_limit to this value	 */
 235				/* will disable the "pause time exceeded"*/
 236				/* tests.				 */
 237
 238/* Public procedures */
 239
 240/* Initialize the collector.  Portable clients should call GC_INIT() from
 241 * the main program instead.
 242 */
 243GC_API void GC_init(void);
 244
 245/*
 246 * general purpose allocation routines, with roughly malloc calling conv.
 247 * The atomic versions promise that no relevant pointers are contained
 248 * in the object.  The nonatomic versions guarantee that the new object
 249 * is cleared.  GC_malloc_stubborn promises that no changes to the object
 250 * will occur after GC_end_stubborn_change has been called on the
 251 * result of GC_malloc_stubborn. GC_malloc_uncollectable allocates an object
 252 * that is scanned for pointers to collectable objects, but is not itself
 253 * collectable.  The object is scanned even if it does not appear to
 254 * be reachable.  GC_malloc_uncollectable and GC_free called on the resulting
 255 * object implicitly update GC_non_gc_bytes appropriately.
 256 *
 257 * Note that the GC_malloc_stubborn support is stubbed out by default
 258 * starting in 6.0.  GC_malloc_stubborn is an alias for GC_malloc unless
 259 * the collector is built with STUBBORN_ALLOC defined.
 260 */
 261GC_API void * GC_malloc(size_t size_in_bytes);
 262GC_API void * GC_malloc_atomic(size_t size_in_bytes);
 263GC_API char * GC_strdup (const char *str);
 264GC_API void * GC_malloc_uncollectable(size_t size_in_bytes);
 265GC_API void * GC_malloc_stubborn(size_t size_in_bytes);
 266
 267/* The following is only defined if the library has been suitably	*/
 268/* compiled:								*/
 269GC_API void * GC_malloc_atomic_uncollectable(size_t size_in_bytes);
 270
 271/* Explicitly deallocate an object.  Dangerous if used incorrectly.     */
 272/* Requires a pointer to the base of an object.				*/
 273/* If the argument is stubborn, it should not be changeable when freed. */
 274/* An object should not be enable for finalization when it is 		*/
 275/* explicitly deallocated.						*/
 276/* GC_free(0) is a no-op, as required by ANSI C for free.		*/
 277GC_API void GC_free(void * object_addr);
 278
 279/*
 280 * Stubborn objects may be changed only if the collector is explicitly informed.
 281 * The collector is implicitly informed of coming change when such
 282 * an object is first allocated.  The following routines inform the
 283 * collector that an object will no longer be changed, or that it will
 284 * once again be changed.  Only nonNIL pointer stores into the object
 285 * are considered to be changes.  The argument to GC_end_stubborn_change
 286 * must be exacly the value returned by GC_malloc_stubborn or passed to
 287 * GC_change_stubborn.  (In the second case it may be an interior pointer
 288 * within 512 bytes of the beginning of the objects.)
 289 * There is a performance penalty for allowing more than
 290 * one stubborn object to be changed at once, but it is acceptable to
 291 * do so.  The same applies to dropping stubborn objects that are still
 292 * changeable.
 293 */
 294GC_API void GC_change_stubborn(void *);
 295GC_API void GC_end_stubborn_change(void *);
 296
 297/* Return a pointer to the base (lowest address) of an object given	*/
 298/* a pointer to a location within the object.				*/
 299/* I.e. map an interior pointer to the corresponding bas pointer.	*/
 300/* Note that with debugging allocation, this returns a pointer to the	*/
 301/* actual base of the object, i.e. the debug information, not to	*/
 302/* the base of the user object.						*/
 303/* Return 0 if displaced_pointer doesn't point to within a valid	*/
 304/* object.								*/
 305/* Note that a deallocated object in the garbage collected heap		*/
 306/* may be considered valid, even if it has been deallocated with	*/
 307/* GC_free.								*/
 308GC_API void * GC_base(void * displaced_pointer);
 309
 310/* Given a pointer to the base of an object, return its size in bytes.	*/
 311/* The returned size may be slightly larger than what was originally	*/
 312/* requested.								*/
 313GC_API size_t GC_size(void * object_addr);
 314
 315/* For compatibility with C library.  This is occasionally faster than	*/
 316/* a malloc followed by a bcopy.  But if you rely on that, either here	*/
 317/* or with the standard C library, your code is broken.  In my		*/
 318/* opinion, it shouldn't have been invented, but now we're stuck. -HB	*/
 319/* The resulting object has the same kind as the original.		*/
 320/* If the argument is stubborn, the result will have changes enabled.	*/
 321/* It is an error to have changes enabled for the original object.	*/
 322/* Follows ANSI comventions for NULL old_object.			*/
 323GC_API void * GC_realloc(void * old_object, size_t new_size_in_bytes);
 324				   
 325/* Explicitly increase the heap size.	*/
 326/* Returns 0 on failure, 1 on success.  */
 327GC_API int GC_expand_hp(size_t number_of_bytes);
 328
 329/* Limit the heap size to n bytes.  Useful when you're debugging, 	*/
 330/* especially on systems that don't handle running out of memory well.	*/
 331/* n == 0 ==> unbounded.  This is the default.				*/
 332GC_API void GC_set_max_heap_size(GC_word n);
 333
 334/* Inform the collector that a certain section of statically allocated	*/
 335/* memory contains no pointers to garbage collected memory.  Thus it 	*/
 336/* need not be scanned.  This is sometimes important if the application */
 337/* maps large read/write files into the address space, which could be	*/
 338/* mistaken for dynamic library data segments on some systems.		*/
 339GC_API void GC_exclude_static_roots(void * low_address,
 340				    void * high_address_plus_1);
 341
 342/* Clear the set of root segments.  Wizards only. */
 343GC_API void GC_clear_roots(void);
 344
 345/* Add a root segment.  Wizards only. */
 346GC_API void GC_add_roots(void * low_address, void * high_address_plus_1);
 347
 348/* Remove a root segment.  Wizards only. */
 349GC_API void GC_remove_roots(void * low_address, void * high_address_plus_1);
 350
 351/* Add a displacement to the set of those considered valid by the	*/
 352/* collector.  GC_register_displacement(n) means that if p was returned */
 353/* by GC_malloc, then (char *)p + n will be considered to be a valid	*/
 354/* pointer to p.  N must be small and less than the size of p.		*/
 355/* (All pointers to the interior of objects from the stack are		*/
 356/* considered valid in any case.  This applies to heap objects and	*/
 357/* static data.)							*/
 358/* Preferably, this should be called before any other GC procedures.	*/
 359/* Calling it later adds to the probability of excess memory		*/
 360/* retention.								*/
 361/* This is a no-op if the collector has recognition of			*/
 362/* arbitrary interior pointers enabled, which is now the default.	*/
 363GC_API void GC_register_displacement(size_t n);
 364
 365/* The following version should be used if any debugging allocation is	*/
 366/* being done.								*/
 367GC_API void GC_debug_register_displacement(size_t n);
 368
 369/* Explicitly trigger a full, world-stop collection. 	*/
 370GC_API void GC_gcollect(void);
 371
 372/* Trigger a full world-stopped collection.  Abort the collection if 	*/
 373/* and when stop_func returns a nonzero value.  Stop_func will be 	*/
 374/* called frequently, and should be reasonably fast.  This works even	*/
 375/* if virtual dirty bits, and hence incremental collection is not 	*/
 376/* available for this architecture.  Collections can be aborted faster	*/
 377/* than normal pause times for incremental collection.  However,	*/
 378/* aborted collections do no useful work; the next collection needs	*/
 379/* to start from the beginning.						*/
 380/* Return 0 if the collection was aborted, 1 if it succeeded.		*/
 381typedef int (* GC_stop_func)(void);
 382GC_API int GC_try_to_collect(GC_stop_func stop_func);
 383
 384/* Return the number of bytes in the heap.  Excludes collector private	*/
 385/* data structures.  Includes empty blocks and fragmentation loss.	*/
 386/* Includes some pages that were allocated but never written.		*/
 387GC_API size_t GC_get_heap_size(void);
 388
 389/* Return a lower bound on the number of free bytes in the heap.	*/
 390GC_API size_t GC_get_free_bytes(void);
 391
 392/* Return the number of bytes allocated since the last collection.	*/
 393GC_API size_t GC_get_bytes_since_gc(void);
 394
 395/* Return the total number of bytes allocated in this process.		*/
 396/* Never decreases, except due to wrapping.				*/
 397GC_API size_t GC_get_total_bytes(void);
 398
 399/* Disable garbage collection.  Even GC_gcollect calls will be 		*/
 400/* ineffective.								*/
 401GC_API void GC_disable(void);
 402
 403/* Reenable garbage collection.  GC_disable() and GC_enable() calls 	*/
 404/* nest.  Garbage collection is enabled if the number of calls to both	*/
 405/* both functions is equal.						*/
 406GC_API void GC_enable(void);
 407
 408/* Enable incremental/generational collection.	*/
 409/* Not advisable unless dirty bits are 		*/
 410/* available or most heap objects are		*/
 411/* pointerfree(atomic) or immutable.		*/
 412/* Don't use in leak finding mode.		*/
 413/* Ignored if GC_dont_gc is true.		*/
 414/* Only the generational piece of this is	*/
 415/* functional if GC_parallel is TRUE		*/
 416/* or if GC_time_limit is GC_TIME_UNLIMITED.	*/
 417/* Causes GC_local_gcj_malloc() to revert to	*/
 418/* locked allocation.  Must be called 		*/
 419/* before any GC_local_gcj_malloc() calls.	*/
 420/* For best performance, should be called as early as possible.	*/
 421/* On some platforms, calling it later may have adverse effects.*/
 422/* Safe to call before GC_INIT().  Includes a GC_init() call.	*/
 423GC_API void GC_enable_incremental(void);
 424
 425/* Does incremental mode write-protect pages?  Returns zero or	*/
 426/* more of the following, or'ed together:			*/
 427#define GC_PROTECTS_POINTER_HEAP  1 /* May protect non-atomic objs.	*/
 428#define GC_PROTECTS_PTRFREE_HEAP  2
 429#define GC_PROTECTS_STATIC_DATA   4 /* Currently never.			*/
 430#define GC_PROTECTS_STACK	  8 /* Probably impractical.		*/
 431
 432#define GC_PROTECTS_NONE 0
 433GC_API int GC_incremental_protection_needs(void);
 434
 435/* Perform some garbage collection work, if appropriate.	*/
 436/* Return 0 if there is no more work to be done.		*/
 437/* Typically performs an amount of work corresponding roughly	*/
 438/* to marking from one page.  May do more work if further	*/
 439/* progress requires it, e.g. if incremental collection is	*/
 440/* disabled.  It is reasonable to call this in a wait loop	*/
 441/* until it returns 0.						*/
 442GC_API int GC_collect_a_little(void);
 443
 444/* Allocate an object of size lb bytes.  The client guarantees that	*/
 445/* as long as the object is live, it will be referenced by a pointer	*/
 446/* that points to somewhere within the first 256 bytes of the object.	*/
 447/* (This should normally be declared volatile to prevent the compiler	*/
 448/* from invalidating this assertion.)  This routine is only useful	*/
 449/* if a large array is being allocated.  It reduces the chance of 	*/
 450/* accidentally retaining such an array as a result of scanning an	*/
 451/* integer that happens to be an address inside the array.  (Actually,	*/
 452/* it reduces the chance of the allocator not finding space for such	*/
 453/* an array, since it will try hard to avoid introducing such a false	*/
 454/* reference.)  On a SunOS 4.X or MS Windows system this is recommended */
 455/* for arrays likely to be larger than 100K or so.  For other systems,	*/
 456/* or if the collector is not configured to recognize all interior	*/
 457/* pointers, the threshold is normally much higher.			*/
 458GC_API void * GC_malloc_ignore_off_page(size_t lb);
 459GC_API void * GC_malloc_atomic_ignore_off_page(size_t lb);
 460
 461#if defined(__sgi) && !defined(__GNUC__) && _COMPILER_VERSION >= 720
 462#   define GC_ADD_CALLER
 463#   define GC_RETURN_ADDR (GC_word)__return_address
 464#endif
 465
 466#if defined(__linux__) || defined(__GLIBC__)
 467# include <features.h>
 468# if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1 || __GLIBC__ > 2) \
 469     && !defined(__ia64__) && !defined(__UCLIBC__)
 470#   ifndef GC_HAVE_BUILTIN_BACKTRACE
 471#     ifndef __UCLIBC__
 472#       define GC_HAVE_BUILTIN_BACKTRACE
 473#     endif
 474#   endif
 475# endif
 476# if defined(__i386__) || defined(__x86_64__)
 477#   define GC_CAN_SAVE_CALL_STACKS
 478# endif
 479#endif
 480
 481#if defined(_MSC_VER) && _MSC_VER >= 1200 /* version 12.0+ (MSVC 6.0+)  */ \
 482    && !defined(_AMD64_)
 483# ifndef GC_HAVE_NO_BUILTIN_BACKTRACE
 484#   define GC_HAVE_BUILTIN_BACKTRACE
 485# endif
 486#endif
 487
 488#if defined(GC_HAVE_BUILTIN_BACKTRACE) && !defined(GC_CAN_SAVE_CALL_STACKS)
 489# define GC_CAN_SAVE_CALL_STACKS
 490#endif
 491
 492#if defined(__sparc__)
 493#   define GC_CAN_SAVE_CALL_STACKS
 494#endif
 495
 496/* If we're on an a platform on which we can't save call stacks, but	*/
 497/* gcc is normally used, we go ahead and define GC_ADD_CALLER.  	*/
 498/* We make this decision independent of whether gcc is actually being	*/
 499/* used, in order to keep the interface consistent, and allow mixing	*/
 500/* of compilers.							*/
 501/* This may also be desirable if it is possible but expensive to	*/
 502/* retrieve the call chain.						*/
 503#if (defined(__linux__) || defined(__NetBSD__) || defined(__OpenBSD__) \
 504     || defined(__FreeBSD__) || defined(__DragonFly__)) & !defined(GC_CAN_SAVE_CALL_STACKS)
 505# define GC_ADD_CALLER
 506# if __GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95) 
 507    /* gcc knows how to retrieve return address, but we don't know */
 508    /* how to generate call stacks.				   */
 509#   define GC_RETURN_ADDR (GC_word)__builtin_return_address(0)
 510# else
 511    /* Just pass 0 for gcc compatibility. */
 512#   define GC_RETURN_ADDR 0
 513# endif
 514#endif
 515
 516#ifdef GC_ADD_CALLER
 517#  define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__
 518#  define GC_EXTRA_PARAMS GC_word ra, const char * s, int i
 519#else
 520#  define GC_EXTRAS __FILE__, __LINE__
 521#  define GC_EXTRA_PARAMS const char * s, int i
 522#endif
 523
 524/* Debugging (annotated) allocation.  GC_gcollect will check 		*/
 525/* objects allocated in this way for overwrites, etc.			*/
 526GC_API void * GC_debug_malloc(size_t size_in_bytes, GC_EXTRA_PARAMS);
 527GC_API void * GC_debug_malloc_atomic(size_t size_in_bytes, GC_EXTRA_PARAMS);
 528GC_API char * GC_debug_strdup(const char *str, GC_EXTRA_PARAMS);
 529GC_API void * GC_debug_malloc_uncollectable
 530	(size_t size_in_bytes, GC_EXTRA_PARAMS);
 531GC_API void * GC_debug_malloc_stubborn
 532	(size_t size_in_bytes, GC_EXTRA_PARAMS);
 533GC_API void * GC_debug_malloc_ignore_off_page
 534	(size_t size_in_bytes, GC_EXTRA_PARAMS);
 535GC_API void * GC_debug_malloc_atomic_ignore_off_page
 536	(size_t size_in_bytes, GC_EXTRA_PARAMS);
 537GC_API void GC_debug_free (void * object_addr);
 538GC_API void * GC_debug_realloc
 539	(void * old_object, size_t new_size_in_bytes, GC_EXTRA_PARAMS);
 540GC_API void GC_debug_change_stubborn(void *);
 541GC_API void GC_debug_end_stubborn_change(void *);
 542
 543/* Routines that allocate objects with debug information (like the 	*/
 544/* above), but just fill in dummy file and line number information.	*/
 545/* Thus they can serve as drop-in malloc/realloc replacements.  This	*/
 546/* can be useful for two reasons:  					*/
 547/* 1) It allows the collector to be built with DBG_HDRS_ALL defined	*/
 548/*    even if some allocation calls come from 3rd party libraries	*/
 549/*    that can't be recompiled.						*/
 550/* 2) On some platforms, the file and line information is redundant,	*/
 551/*    since it can be reconstructed from a stack trace.  On such	*/
 552/*    platforms it may be more convenient not to recompile, e.g. for	*/
 553/*    leak detection.  This can be accomplished by instructing the	*/
 554/*    linker to replace malloc/realloc with these.			*/
 555GC_API void * GC_debug_malloc_replacement (size_t size_in_bytes);
 556GC_API void * GC_debug_realloc_replacement
 557	      (void * object_addr, size_t size_in_bytes);
 558  			 	 
 559# ifdef GC_DEBUG
 560#   define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS)
 561#   define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS)
 562#   define GC_STRDUP(s) GC_debug_strdup((s), GC_EXTRAS)
 563#   define GC_MALLOC_UNCOLLECTABLE(sz) \
 564			GC_debug_malloc_uncollectable(sz, GC_EXTRAS)
 565#   define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
 566			GC_debug_malloc_ignore_off_page(sz, GC_EXTRAS)
 567#   define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
 568			GC_debug_malloc_atomic_ignore_off_page(sz, GC_EXTRAS)
 569#   define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, GC_EXTRAS)
 570#   define GC_FREE(p) GC_debug_free(p)
 571#   define GC_REGISTER_FINALIZER(p, f, d, of, od) \
 572	GC_debug_register_finalizer(p, f, d, of, od)
 573#   define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
 574	GC_debug_register_finalizer_ignore_self(p, f, d, of, od)
 575#   define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
 576	GC_debug_register_finalizer_no_order(p, f, d, of, od)
 577#   define GC_REGISTER_FINALIZER_UNREACHABLE(p, f, d, of, od) \
 578	GC_debug_register_finalizer_unreachable(p, f, d, of, od)
 579#   define GC_MALLOC_STUBBORN(sz) GC_debug_malloc_stubborn(sz, GC_EXTRAS);
 580#   define GC_CHANGE_STUBBORN(p) GC_debug_change_stubborn(p)
 581#   define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
 582#   define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
 583	GC_general_register_disappearing_link(link, GC_base(obj))
 584#   define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
 585# else
 586#   define GC_MALLOC(sz) GC_malloc(sz)
 587#   define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
 588#   define GC_STRDUP(s) GC_strdup(s)
 589#   define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz)
 590#   define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
 591			GC_malloc_ignore_off_page(sz)
 592#   define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
 593			GC_malloc_atomic_ignore_off_page(sz)
 594#   define GC_REALLOC(old, sz) GC_realloc(old, sz)
 595#   define GC_FREE(p) GC_free(p)
 596#   define GC_REGISTER_FINALIZER(p, f, d, of, od) \
 597	GC_register_finalizer(p, f, d, of, od)
 598#   define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
 599	GC_register_finalizer_ignore_self(p, f, d, of, od)
 600#   define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
 601	GC_register_finalizer_no_order(p, f, d, of, od)
 602#   define GC_REGISTER_FINALIZER_UNREACHABLE(p, f, d, of, od) \
 603	GC_register_finalizer_unreachable(p, f, d, of, od)
 604#   define GC_MALLOC_STUBBORN(sz) GC_malloc_stubborn(sz)
 605#   define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p)
 606#   define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
 607#   define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
 608	GC_general_register_disappearing_link(link, obj)
 609#   define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
 610# endif
 611/* The following are included because they are often convenient, and	*/
 612/* reduce the chance for a misspecifed size argument.  But calls may	*/
 613/* expand to something syntactically incorrect if t is a complicated	*/
 614/* type expression.  							*/
 615# define GC_NEW(t) (t *)GC_MALLOC(sizeof (t))
 616# define GC_NEW_ATOMIC(t) (t *)GC_MALLOC_ATOMIC(sizeof (t))
 617# define GC_NEW_STUBBORN(t) (t *)GC_MALLOC_STUBBORN(sizeof (t))
 618# define GC_NEW_UNCOLLECTABLE(t) (t *)GC_MALLOC_UNCOLLECTABLE(sizeof (t))
 619
 620/* Finalization.  Some of these primitives are grossly unsafe.		*/
 621/* The idea is to make them both cheap, and sufficient to build		*/
 622/* a safer layer, closer to Modula-3, Java, or PCedar finalization.	*/
 623/* The interface represents my conclusions from a long discussion	*/
 624/* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes, 		*/
 625/* Christian Jacobi, and Russ Atkinson.  It's not perfect, and		*/
 626/* probably nobody else agrees with it.	    Hans-J. Boehm  3/13/92	*/
 627typedef void (*GC_finalization_proc) (void * obj, void * client_data);
 628
 629GC_API void GC_register_finalizer(void * obj, GC_finalization_proc fn,
 630				  void * cd, GC_finalization_proc *ofn,
 631				  void * *ocd);
 632GC_API void GC_debug_register_finalizer
 633    	         (void * obj, GC_finalization_proc fn, void * cd,
 634		  GC_finalization_proc *ofn, void * *ocd);
 635	/* When obj is no longer accessible, invoke		*/
 636	/* (*fn)(obj, cd).  If a and b are inaccessible, and	*/
 637	/* a points to b (after disappearing links have been	*/
 638	/* made to disappear), then only a will be		*/
 639	/* finalized.  (If this does not create any new		*/
 640	/* pointers to b, then b will be finalized after the	*/
 641	/* next collection.)  Any finalizable object that	*/
 642	/* is reachable from itself by following one or more	*/
 643	/* pointers will not be finalized (or collected).	*/
 644	/* Thus cycles involving finalizable objects should	*/
 645	/* be avoided, or broken by disappearing links.		*/
 646	/* All but the last finalizer registered for an object  */
 647	/* is ignored.						*/
 648	/* Finalization may be removed by passing 0 as fn.	*/
 649	/* Finalizers are implicitly unregistered just before   */
 650	/* they are invoked.					*/
 651	/* The old finalizer and client data are stored in	*/
 652	/* *ofn and *ocd.					*/ 
 653	/* Fn is never invoked on an accessible object,		*/
 654	/* provided hidden pointers are converted to real 	*/
 655	/* pointers only if the allocation lock is held, and	*/
 656	/* such conversions are not performed by finalization	*/
 657	/* routines.						*/
 658	/* If GC_register_finalizer is aborted as a result of	*/
 659	/* a signal, the object may be left with no		*/
 660	/* finalization, even if neither the old nor new	*/
 661	/* finalizer were NULL.					*/
 662	/* Obj should be the nonNULL starting address of an 	*/
 663	/* object allocated by GC_malloc or friends.		*/
 664	/* Note that any garbage collectable object referenced	*/
 665	/* by cd will be considered accessible until the	*/
 666	/* finalizer is invoked.				*/
 667
 668/* Another versions of the above follow.  It ignores		*/
 669/* self-cycles, i.e. pointers from a finalizable object to	*/
 670/* itself.  There is a stylistic argument that this is wrong,	*/
 671/* but it's unavoidable for C++, since the compiler may		*/
 672/* silently introduce these.  It's also benign in that specific	*/
 673/* case.  And it helps if finalizable objects are split to	*/
 674/* avoid cycles.						*/
 675/* Note that cd will still be viewed as accessible, even if it	*/
 676/* refers to the object itself.					*/
 677GC_API void GC_register_finalizer_ignore_self
 678		(void * obj, GC_finalization_proc fn, void * cd,
 679		 GC_finalization_proc *ofn, void * *ocd);
 680GC_API void GC_debug_register_finalizer_ignore_self
 681		(void * obj, GC_finalization_proc fn, void * cd,
 682		 GC_finalization_proc *ofn, void * *ocd);
 683
 684/* Another version of the above.  It ignores all cycles.        */
 685/* It should probably only be used by Java implementations.     */
 686/* Note that cd will still be viewed as accessible, even if it	*/
 687/* refers to the object itself.					*/
 688GC_API void GC_register_finalizer_no_order
 689	  	(void * obj, GC_finalization_proc fn, void * cd,
 690	 	 GC_finalization_proc *ofn, void * *ocd);
 691GC_API void GC_debug_register_finalizer_no_order
 692		(void * obj, GC_finalization_proc fn, void * cd,
 693		 GC_finalization_proc *ofn, void * *ocd);
 694
 695/* This is a special finalizer that is useful when an object's  */
 696/* finalizer must be run when the object is known to be no      */
 697/* longer reachable, not even from other finalizable objects.   */
 698/* It behaves like "normal" finalization, except that the 	*/
 699/* finalizer is not run while the object is reachable from	*/
 700/* other objects specifying unordered finalization.		*/
 701/* Effectively it allows an object referenced, possibly		*/
 702/* indirectly, from an unordered finalizable object to override */
 703/* the unordered finalization request.				*/
 704/* This can be used in combination with finalizer_no_order so   */
 705/* as to release resources that must not be released while an   */
 706/* object can still be brought back to life by other            */
 707/* finalizers.                                                  */
 708/* Only works if GC_java_finalization is set.  Probably only 	*/
 709/* of interest when implementing a language that requires	*/
 710/* unordered finalization (e.g. Java, C#).			*/
 711GC_API void GC_register_finalizer_unreachable
 712	         (void * obj, GC_finalization_proc fn, void * cd,
 713		  GC_finalization_proc *ofn, void * *ocd);
 714GC_API void GC_debug_register_finalizer_unreachable
 715		 (void * obj, GC_finalization_proc fn, void * cd,
 716		  GC_finalization_proc *ofn, void * *ocd);
 717
 718/* The following routine may be used to break cycles between	*/
 719/* finalizable objects, thus causing cyclic finalizable		*/
 720/* objects to be finalized in the correct order.  Standard	*/
 721/* use involves calling GC_register_disappearing_link(&p),	*/
 722/* where p is a pointer that is not followed by finalization	*/
 723/* code, and should not be considered in determining 		*/
 724/* finalization order.						*/
 725GC_API int GC_register_disappearing_link(void * * link );
 726	/* Link should point to a field of a heap allocated 	*/
 727	/* object obj.  *link will be cleared when obj is	*/
 728	/* found to be inaccessible.  This happens BEFORE any	*/
 729	/* finalization code is invoked, and BEFORE any		*/
 730	/* decisions about finalization order are made.		*/
 731	/* This is useful in telling the finalizer that 	*/
 732	/* some pointers are not essential for proper		*/
 733	/* finalization.  This may avoid finalization cycles.	*/
 734	/* Note that obj may be resurrected by another		*/
 735	/* finalizer, and thus the clearing of *link may	*/
 736	/* be visible to non-finalization code.  		*/
 737	/* There's an argument that an arbitrary action should  */
 738	/* be allowed here, instead of just clearing a pointer. */
 739	/* But this causes problems if that action alters, or 	*/
 740	/* examines connectivity.				*/
 741	/* Returns 1 if link was already registered, 0 if	*/
 742	/* registration succeeded, 2 if it failed for lack of	*/
 743	/* memory, and GC_oom_fn did not handle the problem.	*/
 744	/* Only exists for backward compatibility.  See below:	*/
 745	
 746GC_API int GC_general_register_disappearing_link (void * * link, void * obj);
 747	/* A slight generalization of the above. *link is	*/
 748	/* cleared when obj first becomes inaccessible.  This	*/
 749	/* can be used to implement weak pointers easily and	*/
 750	/* safely. Typically link will point to a location	*/
 751	/* holding a disguised pointer to obj.  (A pointer 	*/
 752	/* inside an "atomic" object is effectively  		*/
 753	/* disguised.)   In this way soft			*/
 754	/* pointers are broken before any object		*/
 755	/* reachable from them are finalized.  Each link	*/
 756	/* May be registered only once, i.e. with one obj	*/
 757	/* value.  This was added after a long email discussion */
 758	/* with John Ellis.					*/
 759	/* Obj must be a pointer to the first word of an object */
 760	/* we allocated.  It is unsafe to explicitly deallocate */
 761	/* the object containing link.  Explicitly deallocating */
 762	/* obj may or may not cause link to eventually be	*/
 763	/* cleared.						*/
 764	/* This can be used to implement certain types of	*/
 765	/* weak pointers.  Note however that this generally	*/
 766	/* requires that thje allocation lock is held (see	*/
 767	/* GC_call_with_allock_lock() below) when the disguised	*/
 768	/* pointer is accessed.  Otherwise a strong pointer	*/
 769	/* could be recreated between the time the collector    */
 770	/* decides to reclaim the object and the link is	*/
 771	/* cleared.						*/
 772
 773GC_API int GC_unregister_disappearing_link (void * * link);
 774	/* Returns 0 if link was not actually registered.	*/
 775	/* Undoes a registration by either of the above two	*/
 776	/* routines.						*/
 777
 778/* Returns !=0  if GC_invoke_finalizers has something to do. 		*/
 779GC_API int GC_should_invoke_finalizers(void);
 780
 781GC_API int GC_invoke_finalizers(void);
 782	/* Run finalizers for all objects that are ready to	*/
 783	/* be finalized.  Return the number of finalizers	*/
 784	/* that were run.  Normally this is also called		*/
 785	/* implicitly during some allocations.	If		*/
 786	/* GC-finalize_on_demand is nonzero, it must be called	*/
 787	/* explicitly.						*/
 788
 789/* Explicitly tell the collector that an object is reachable	*/
 790/* at a particular program point.  This prevents the argument	*/
 791/* pointer from being optimized away, even it is otherwise no	*/
 792/* longer needed.  It should have no visible effect in the	*/
 793/* absence of finalizers or disappearing links.  But it may be	*/
 794/* needed to prevent finalizers from running while the		*/
 795/* associated external resource is still in use.		*/
 796/* The function is sometimes called keep_alive in other		*/
 797/* settings.							*/
 798# if defined(__GNUC__) && !defined(__INTEL_COMPILER)
 799#   define GC_reachable_here(ptr) \
 800    __asm__ volatile(" " : : "X"(ptr) : "memory");
 801# else
 802    GC_API void GC_noop1(GC_word x);
 803#   define GC_reachable_here(ptr) GC_noop1((GC_word)(ptr));
 804#endif
 805
 806/* GC_set_warn_proc can be used to redirect or filter warning messages.	*/
 807/* p may not be a NULL pointer.						*/
 808typedef void (*GC_warn_proc) (char *msg, GC_word arg);
 809GC_API GC_warn_proc GC_set_warn_proc(GC_warn_proc p);
 810    /* Returns old warning procedure.	*/
 811
 812GC_API GC_word GC_set_free_space_divisor(GC_word value);
 813    /* Set free_space_divisor.  See above for definition.	*/
 814    /* Returns old value.					*/
 815	
 816/* The following is intended to be used by a higher level	*/
 817/* (e.g. Java-like) finalization facility.  It is expected	*/
 818/* that finalization code will arrange for hidden pointers to	*/
 819/* disappear.  Otherwise objects can be accessed after they	*/
 820/* have been collected.						*/
 821/* Note that putting pointers in atomic objects or in 		*/
 822/* nonpointer slots of "typed" objects is equivalent to 	*/
 823/* disguising them in this way, and may have other advantages.	*/
 824# if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
 825    typedef GC_word GC_hidden_pointer;
 826#   define HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
 827#   define REVEAL_POINTER(p) ((void *)(HIDE_POINTER(p)))
 828    /* Converting a hidden pointer to a real pointer requires verifying	*/
 829    /* that the object still exists.  This involves acquiring the  	*/
 830    /* allocator lock to avoid a race with the collector.		*/
 831# endif /* I_HIDE_POINTERS */
 832
 833typedef void * (*GC_fn_type) (void * client_data);
 834GC_API void * GC_call_with_alloc_lock (GC_fn_type fn, void * client_data);
 835
 836/* These routines are intended to explicitly notify the collector	*/
 837/* of new threads.  Often this is unnecessary because thread creation	*/
 838/* is implicitly intercepted by the collector, using header-file	*/
 839/* defines, or linker-based interception.  In the long run the intent	*/
 840/* is to always make redundant registration safe.  In the short run,	*/
 841/* this is being implemented a platform at a time.			*/
 842/* The interface is complicated by the fact that we probably will not 	*/
 843/* ever be able to automatically determine the stack base for thread	*/
 844/* stacks on all platforms.						*/
 845
 846/* Structure representing the base of a thread stack.  On most		*/
 847/* platforms this contains just a single address.			*/
 848struct GC_stack_base {
 849	void * mem_base;	/* Base of memory stack.	*/
 850#	if defined(__ia64) || defined(__ia64__)
 851	  void * reg_base;	/* Base of separate register stack.	*/
 852#	endif
 853};
 854
 855typedef void * (*GC_stack_base_func)(struct GC_stack_base *sb, void *arg);
 856
 857/* Call a function with a stack base structure corresponding to		*/
 858/* somewhere in the GC_call_with_stack_base frame.  This often can	*/
 859/* be used to provide a sufficiently accurate stack base.  And we 	*/
 860/* implement it everywhere.						*/
 861GC_API void * GC_call_with_stack_base(GC_stack_base_func fn, void *arg);
 862
 863/* Register the current thread, with the indicated stack base, as	*/
 864/* a new thread whose stack(s) should be traced by the GC.  If a 	*/
 865/* platform does not implicitly do so, this must be called before a	*/
 866/* thread can allocate garbage collected memory, or assign pointers	*/
 867/* to the garbage collected heap.  Once registered, a thread will be	*/
 868/* stopped during garbage collections.					*/
 869/* Return codes:	*/
 870#define GC_SUCCESS 0
 871#define GC_DUPLICATE 1	/* Was already registered.	*/
 872#define GC_NO_THREADS 2	/* No thread support in GC.  	*/
 873#define GC_UNIMPLEMENTED 3	/* Not yet implemented on this platform. */
 874GC_API int GC_register_my_thread(struct GC_stack_base *);
 875
 876/* Unregister the current thread.  The thread may no longer allocate	*/
 877/* garbage collected memory or manipulate pointers to the		*/
 878/* garbage collected heap after making this call.			*/
 879/* Specifically, if it wants to return or otherwise communicate a 	*/
 880/* pointer to the garbage-collected heap to another thread, it must	*/
 881/* do this before calling GC_unregister_my_thread, most probably	*/
 882/* by saving it in a global data structure.				*/
 883GC_API int GC_unregister_my_thread(void);
 884
 885/* Attempt to fill in the GC_stack_base structure with the stack base	*/
 886/* for this thread.  This appears to be required to implement anything	*/
 887/* like the JNI AttachCurrentThread in an environment in which new	*/
 888/* threads are not automatically registered with the collector.		*/
 889/* It is also unfortunately hard to implement well on many platforms.	*/
 890/* Returns GC_SUCCESS or GC_UNIMPLEMENTED.				*/
 891GC_API int GC_get_stack_base(struct GC_stack_base *);
 892
 893/* The following routines are primarily intended for use with a 	*/
 894/* preprocessor which inserts calls to check C pointer arithmetic.	*/
 895/* They indicate failure by invoking the corresponding _print_proc.	*/
 896
 897/* Check that p and q point to the same object.  		*/
 898/* Fail conspicuously if they don't.				*/
 899/* Returns the first argument.  				*/
 900/* Succeeds if neither p nor q points to the heap.		*/
 901/* May succeed if both p and q point to between heap objects.	*/
 902GC_API void * GC_same_obj (void * p, void * q);
 903
 904/* Checked pointer pre- and post- increment operations.  Note that	*/
 905/* the second argument is in units of bytes, not multiples of the	*/
 906/* object size.  This should either be invoked from a macro, or the	*/
 907/* call should be automatically generated.				*/
 908GC_API void * GC_pre_incr (void * *p, size_t how_much);
 909GC_API void * GC_post_incr (void * *p, size_t how_much);
 910
 911/* Check that p is visible						*/
 912/* to the collector as a possibly pointer containing location.		*/
 913/* If it isn't fail conspicuously.					*/
 914/* Returns the argument in all cases.  May erroneously succeed		*/
 915/* in hard cases.  (This is intended for debugging use with		*/
 916/* untyped allocations.  The idea is that it should be possible, though	*/
 917/* slow, to add such a call to all indirect pointer stores.)		*/
 918/* Currently useless for multithreaded worlds.				*/
 919GC_API void * GC_is_visible (void * p);
 920
 921/* Check that if p is a pointer to a heap page, then it points to	*/
 922/* a valid displacement within a heap object.				*/
 923/* Fail conspicuously if this property does not hold.			*/
 924/* Uninteresting with GC_all_interior_pointers.				*/
 925/* Always returns its argument.						*/
 926GC_API void * GC_is_valid_displacement (void *	p);
 927
 928/* Explicitly dump the GC state.  This is most often called from the	*/
 929/* debugger, or by setting the GC_DUMP_REGULARLY environment variable,	*/
 930/* but it may be useful to call it from client code during debugging.	*/
 931void GC_dump(void);
 932
 933/* Safer, but slow, pointer addition.  Probably useful mainly with 	*/
 934/* a preprocessor.  Useful only for heap pointers.			*/
 935#ifdef GC_DEBUG
 936#   define GC_PTR_ADD3(x, n, type_of_result) \
 937	((type_of_result)GC_same_obj((x)+(n), (x)))
 938#   define GC_PRE_INCR3(x, n, type_of_result) \
 939	((type_of_result)GC_pre_incr(&(x), (n)*sizeof(*x))
 940#   define GC_POST_INCR2(x, type_of_result) \
 941	((type_of_result)GC_post_incr(&(x), sizeof(*x))
 942#   ifdef __GNUC__
 943#       define GC_PTR_ADD(x, n) \
 944	    GC_PTR_ADD3(x, n, typeof(x))
 945#       define GC_PRE_INCR(x, n) \
 946	    GC_PRE_INCR3(x, n, typeof(x))
 947#       define GC_POST_INCR(x, n) \
 948	    GC_POST_INCR3(x, typeof(x))
 949#   else
 950	/* We can't do this right without typeof, which ANSI	*/
 951	/* decided was not sufficiently useful.  Repeatedly	*/
 952	/* mentioning the arguments seems too dangerous to be	*/
 953	/* useful.  So does not casting the result.		*/
 954#   	define GC_PTR_ADD(x, n) ((x)+(n))
 955#   endif
 956#else	/* !GC_DEBUG */
 957#   define GC_PTR_ADD3(x, n, type_of_result) ((x)+(n))
 958#   define GC_PTR_ADD(x, n) ((x)+(n))
 959#   define GC_PRE_INCR3(x, n, type_of_result) ((x) += (n))
 960#   define GC_PRE_INCR(x, n) ((x) += (n))
 961#   define GC_POST_INCR2(x, n, type_of_result) ((x)++)
 962#   define GC_POST_INCR(x, n) ((x)++)
 963#endif
 964
 965/* Safer assignment of a pointer to a nonstack location.	*/
 966#ifdef GC_DEBUG
 967#   define GC_PTR_STORE(p, q) \
 968	(*(void **)GC_is_visible(p) = GC_is_valid_displacement(q))
 969#else /* !GC_DEBUG */
 970#   define GC_PTR_STORE(p, q) (*(p) = (q))
 971#endif
 972
 973/* Functions called to report pointer checking errors */
 974GC_API void (*GC_same_obj_print_proc) (void * p, void * q);
 975
 976GC_API void (*GC_is_valid_displacement_print_proc) (void * p);
 977
 978GC_API void (*GC_is_visible_print_proc) (void * p);
 979
 980
 981/* For pthread support, we generally need to intercept a number of 	*/
 982/* thread library calls.  We do that here by macro defining them.	*/
 983
 984#if !defined(GC_USE_LD_WRAP) && !defined(GC_NO_THREAD_REDIRECTS) \
 985    && defined(GC_PTHREADS)
 986# include "gc_pthread_redirects.h"
 987#endif
 988
 989# if defined(PCR) || defined(GC_SOLARIS_THREADS) || \
 990     defined(GC_PTHREADS) || defined(GC_WIN32_THREADS)
 991   	/* Any flavor of threads.	*/
 992/* This returns a list of objects, linked through their first		*/
 993/* word.  Its use can greatly reduce lock contention problems, since	*/
 994/* the allocation lock can be acquired and released many fewer times.	*/
 995/* It is used internally by gc_local_alloc.h, which provides a simpler	*/
 996/* programming interface on Linux.					*/
 997void * GC_malloc_many(size_t lb);
 998#define GC_NEXT(p) (*(void * *)(p)) 	/* Retrieve the next element	*/
 999					/* in returned list.		*/
1000
1001#endif /* THREADS */
1002
1003/* Register a callback to control the scanning of dynamic libraries.
1004   When the GC scans the static data of a dynamic library, it will
1005   first call a user-supplied routine with filename of the library and
1006   the address and length of the memory region.  This routine should
1007   return nonzero if that region should be scanned.  */
1008GC_API void 
1009GC_register_has_static_roots_callback
1010  (int (*callback)(const char *, void *, size_t));
1011
1012
1013#if defined(GC_WIN32_THREADS) && !defined(__CYGWIN32__) \
1014	&& !defined(__CYGWIN__) \
1015	&& !defined(GC_PTHREADS)
1016
1017#ifdef __cplusplus
1018    }  /* Including windows.h in an extern "C" context no longer works. */
1019#endif
1020
1021#ifndef GC_NO_THREAD_DECLS
1022# include <windows.h>
1023
1024#ifdef __cplusplus
1025    extern "C" {
1026#endif
1027  /*
1028   * All threads must be created using GC_CreateThread or GC_beginthreadex,
1029   * or must explicitly call GC_register_my_thread,
1030   * so that they will be recorded in the thread table.
1031   * For backwards compatibility, it is possible to build the GC
1032   * with GC_DLL defined, and to call GC_use_DllMain().
1033   * This implicitly registers all created threads, but appears to be
1034   * less robust.
1035   *
1036   * Currently the collector expects all threads to fall through and
1037   * terminate normally, or call GC_endthreadex() or GC_ExitThread,
1038   * so that the thread is properly unregistered.  (An explicit call
1039   * to GC_unregister_my_thread() should also work, but risks unregistering
1040   * the thread twice.)
1041   */
1042   GC_API HANDLE WINAPI GC_CreateThread(
1043      LPSECURITY_ATTRIBUTES lpThreadAttributes,
1044      DWORD dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress,
1045      LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId );
1046
1047#  if defined(_MSC_VER) && _MSC_VER >= 1200 && !defined(_UINTPTR_T_DEFINED)
1048     typedef unsigned long uintptr_t;
1049#  endif
1050
1051   GC_API uintptr_t GC_beginthreadex(
1052     void *security, unsigned stack_size,
1053     unsigned ( __stdcall *start_address )( void * ),
1054     void *arglist, unsigned initflag, unsigned *thrdaddr);
1055
1056   GC_API void GC_endthreadex(unsigned retval);
1057
1058   GC_API void WINAPI GC_ExitThread(DWORD dwExitCode);
1059
1060# if defined(_WIN32_WCE)
1061  /*
1062   * win32_threads.c implements the real WinMain, which will start a new thread
1063   * to call GC_WinMain after initializing the garbage collector.
1064   */
1065  GC_API int WINAPI GC_WinMain(
1066      HINSTANCE hInstance,
1067      HINSTANCE hPrevInstance,
1068      LPWSTR lpCmdLine,
1069      int nCmdShow );
1070#  ifndef GC_BUILD
1071#    define WinMain GC_WinMain
1072#  endif
1073# endif /* defined(_WIN32_WCE) */
1074#endif /* !GC_NO_THREAD_DECLS */
1075
1076  /*
1077   * Use implicit thread registration via DllMain.
1078   * Must be called before GC_INIT and other GC routines.
1079   * Should be avoided if GC_beginthreadex and friends can be called
1080   * instead.
1081   */
1082GC_API void GC_use_DllMain(void);
1083
1084# ifndef GC_NO_THREAD_REDIRECTS
1085#   define CreateThread GC_CreateThread
1086#   define ExitThread GC_ExitThread
1087#   define _beginthreadex GC_beginthreadex
1088#   define _endthreadex GC_endthreadex
1089#   define _beginthread { > "Please use _beginthreadex instead of _beginthread" < }
1090# endif /* !GC_NO_THREAD_REDIRECTS */
1091
1092#endif /* defined(GC_WIN32_THREADS)  && !cygwin */
1093
1094 /*
1095  * Fully portable code should call GC_INIT() from the main program
1096  * before making any other GC_ calls.  On most platforms this is a
1097  * no-op and the collector self-initializes.  But a number of platforms
1098  * make that too hard.
1099  * A GC_INIT call is required if the collector is built with THREAD_LOCAL_ALLOC
1100  * defined and the initial allocation call is not to GC_malloc() or
1101  * GC_malloc_atomic().
1102  */
1103#if defined(__CYGWIN32__) || defined (_AIX)
1104    /*
1105     * Similarly gnu-win32 DLLs need explicit initialization from
1106     * the main program, as does AIX.
1107     */
1108#   ifdef __CYGWIN32__
1109      extern int _data_start__[];
1110      extern int _data_end__[];
1111      extern int _bss_start__[];
1112      extern int _bss_end__[];
1113#     define GC_MAX(x,y) ((x) > (y) ? (x) : (y))
1114#     define GC_MIN(x,y) ((x) < (y) ? (x) : (y))
1115#     define GC_DATASTART ((void *) GC_MIN(_data_start__, _bss_start__))
1116#     define GC_DATAEND	 ((void *) GC_MAX(_data_end__, _bss_end__))
1117#     define GC_INIT() { GC_add_roots(GC_DATASTART, GC_DATAEND); \
1118			   GC_gcollect(); /* For blackliā€¦

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