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C/C++ Source or Header | 2001-06-19 | 38.7 KB | 919 lines

/* * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers * Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. * Copyright 1996-1999 by Silicon Graphics. All rights reserved. * Copyright 1999 by Hewlett-Packard Company. All rights reserved. * * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. * * Permission is hereby granted to use or copy this program * for any purpose, provided the above notices are retained on all copies. * Permission to modify the code and to distribute modified code is granted, * provided the above notices are retained, and a notice that the code was * modified is included with the above copyright notice. */ /* * Note that this defines a large number of tuning hooks, which can * safely be ignored in nearly all cases. For normal use it suffices * to call only GC_MALLOC and perhaps GC_REALLOC. * For better performance, also look at GC_MALLOC_ATOMIC, and * GC_enable_incremental. If you need an action to be performed * immediately before an object is collected, look at GC_register_finalizer. * If you are using Solaris threads, look at the end of this file. * Everything else is best ignored unless you encounter performance * problems. */ #ifndef _GC_H # define _GC_H #if !_WIN32 #error "GC only supported for Win32 memory model" #endif #pragma comment(lib, "gc.lib") #if defined(_SOLARIS_PTHREADS) && !defined(SOLARIS_THREADS) # define SOLARIS_THREADS #endif /* * Some tests for old macros. These violate our namespace rules and will * disappear shortly. */ #if defined(SOLARIS_THREADS) || defined(_SOLARIS_THREADS) # define GC_SOLARIS_THREADS #endif #if defined(_SOLARIS_PTHREADS) # define GC_SOLARIS_PTHREADS #endif #if defined(IRIX_THREADS) # define GC_IRIX_THREADS #endif #if defined(HPUX_THREADS) # define GC_HPUX_THREADS #endif #if defined(OSF1_THREADS) # define GC_OSF1_THREADS #endif #if defined(LINUX_THREADS) # define GC_LINUX_THREADS #endif #if defined(WIN32_THREADS) # define GC_WIN32_THREADS #endif #if defined(USE_LD_WRAP) # define GC_USE_LD_WRAP #endif #if !defined(_REENTRANT) && (defined(GC_SOLARIS_THREADS) \ || defined(GC_SOLARIS_PTHREADS) \ || defined(GC_HPUX_THREADS) \ || defined(GC_LINUX_THREADS)) # define _REENTRANT /* Better late than never. This fails if system headers that */ /* depend on this were previously included. */ #endif # define __GC # include <stddef.h> # ifdef _WIN32_WCE /* Yet more kluges for WinCE */ # include <stdlib.h> /* size_t is defined here */ typedef long ptrdiff_t; /* ptrdiff_t is not defined */ # endif #if defined(__CYGWIN32__) && defined(GC_USE_DLL) #include "libgc_globals.h" #endif #if defined(__MINGW32__) && defined(WIN32_THREADS) # ifdef GC_BUILD # define GC_API __declspec(dllexport) # else # define GC_API __declspec(dllimport) # endif #endif #if (defined(__DMC__) || defined(_MSC_VER)) \ && (defined(_DLL) && !defined(NOT_GC_DLL) \ || defined(GC_DLL)) # ifdef GC_BUILD # define GC_API extern __declspec(dllexport) # else # define GC_API __declspec(dllimport) # endif #endif #if defined(__WATCOMC__) && defined(GC_DLL) # ifdef GC_BUILD # define GC_API extern __declspec(dllexport) # else # define GC_API extern __declspec(dllimport) # endif #endif #ifndef GC_API #define GC_API extern #endif # if defined(__STDC__) || defined(__cplusplus) # define GC_PROTO(args) args typedef void * GC_PTR; # define GC_CONST const # else # define GC_PROTO(args) () typedef char * GC_PTR; # define GC_CONST # endif # ifdef __cplusplus extern "C" { # endif /* Define word and signed_word to be unsigned and signed types of the */ /* size as char * or void *. There seems to be no way to do this */ /* even semi-portably. The following is probably no better/worse */ /* than almost anything else. */ /* The ANSI standard suggests that size_t and ptr_diff_t might be */ /* better choices. But those appear to have incorrect definitions */ /* on may systems. Notably "typedef int size_t" seems to be both */ /* frequent and WRONG. */ typedef unsigned long GC_word; typedef long GC_signed_word; /* Public read-only variables */ GC_API GC_word GC_gc_no;/* Counter incremented per collection. */ /* Includes empty GCs at startup. */ GC_API int GC_parallel; /* GC is parallelized for performance on */ /* multiprocessors. Currently set only */ /* implicitly if collector is built with */ /* -DPARALLEL_MARK and if either: */ /* Env variable GC_NPROC is set to > 1, or */ /* GC_NPROC is not set and this is an MP. */ /* If GC_parallel is set, incremental */ /* collection is aonly partially functional, */ /* and may not be desirable. */ /* Public R/W variables */ GC_API GC_PTR (*GC_oom_fn) GC_PROTO((size_t bytes_requested)); /* When there is insufficient memory to satisfy */ /* an allocation request, we return */ /* (*GC_oom_fn)(). By default this just */ /* returns 0. */ /* If it returns, it must return 0 or a valid */ /* pointer to a previously allocated heap */ /* object. */ GC_API int GC_find_leak; /* Do not actually garbage collect, but simply */ /* report inaccessible memory that was not */ /* deallocated with GC_free. Initial value */ /* is determined by FIND_LEAK macro. */ GC_API int GC_all_interior_pointers; /* Arrange for pointers to object interiors to */ /* be recognized as valid. May not be changed */ /* after GC initialization. */ /* Initial value is determined by */ /* -DALL_INTERIOR_POINTERS. */ /* Unless DONT_ADD_BYTE_AT_END is defined, this */ /* also affects whether sizes are increased by */ /* at least a byte to allow "off the end" */ /* pointer recognition. */ /* MUST BE 0 or 1. */ GC_API int GC_quiet; /* Disable statistics output. Only matters if */ /* collector has been compiled with statistics */ /* enabled. This involves a performance cost, */ /* and is thus not the default. */ GC_API int GC_finalize_on_demand; /* If nonzero, finalizers will only be run in */ /* response to an explicit GC_invoke_finalizers */ /* call. The default is determined by whether */ /* the FINALIZE_ON_DEMAND macro is defined */ /* when the collector is built. */ GC_API int GC_java_finalization; /* Mark objects reachable from finalizable */ /* objects in a separate postpass. This makes */ /* it a bit safer to use non-topologically- */ /* ordered finalization. Default value is */ /* determined by JAVA_FINALIZATION macro. */ GC_API void (* GC_finalizer_notifier)(); /* Invoked by the collector when there are */ /* objects to be finalized. Invoked at most */ /* once per GC cycle. Never invoked unless */ /* GC_finalize_on_demand is set. */ /* Typically this will notify a finalization */ /* thread, which will call GC_invoke_finalizers */ /* in response. */ GC_API int GC_dont_gc; /* Dont collect unless explicitly requested, e.g. */ /* because it's not safe. */ GC_API int GC_dont_expand; /* Dont expand heap unless explicitly requested */ /* or forced to. */ GC_API int GC_use_entire_heap; /* Causes the nonincremental collector to use the */ /* entire heap before collecting. This was the only */ /* option for GC versions < 5.0. This sometimes */ /* results in more large block fragmentation, since */ /* very larg blocks will tend to get broken up */ /* during each GC cycle. It is likely to result in a */ /* larger working set, but lower collection */ /* frequencies, and hence fewer instructions executed */ /* in the collector. */ GC_API int GC_full_freq; /* Number of partial collections between */ /* full collections. Matters only if */ /* GC_incremental is set. */ /* Full collections are also triggered if */ /* the collector detects a substantial */ /* increase in the number of in-use heap */ /* blocks. Values in the tens are now */ /* perfectly reasonable, unlike for */ /* earlier GC versions. */ GC_API GC_word GC_non_gc_bytes; /* Bytes not considered candidates for collection. */ /* Used only to control scheduling of collections. */ /* Updated by GC_malloc_uncollectable and GC_free. */ /* Wizards only. */ GC_API int GC_no_dls; /* Don't register dynamic library data segments. */ /* Wizards only. Should be used only if the */ /* application explicitly registers all roots. */ /* In Microsoft Windows environments, this will */ /* usually also prevent registration of the */ /* main data segment as part of the root set. */ GC_API GC_word GC_free_space_divisor; /* We try to make sure that we allocate at */ /* least N/GC_free_space_divisor bytes between */ /* collections, where N is the heap size plus */ /* a rough estimate of the root set size. */ /* Initially, GC_free_space_divisor = 4. */ /* Increasing its value will use less space */ /* but more collection time. Decreasing it */ /* will appreciably decrease collection time */ /* at the expense of space. */ /* GC_free_space_divisor = 1 will effectively */ /* disable collections. */ GC_API GC_word GC_max_retries; /* The maximum number of GCs attempted before */ /* reporting out of memory after heap */ /* expansion fails. Initially 0. */ GC_API char *GC_stackbottom; /* Cool end of user stack. */ /* May be set in the client prior to */ /* calling any GC_ routines. This */ /* avoids some overhead, and */ /* potentially some signals that can */ /* confuse debuggers. Otherwise the */ /* collector attempts to set it */ /* automatically. */ /* For multithreaded code, this is the */ /* cold end of the stack for the */ /* primordial thread. */ GC_API int GC_dont_precollect; /* Don't collect as part of */ /* initialization. Should be set only */ /* if the client wants a chance to */ /* manually initialize the root set */ /* before the first collection. */ /* Interferes with blacklisting. */ /* Wizards only. */ /* Public procedures */ /* * general purpose allocation routines, with roughly malloc calling conv. * The atomic versions promise that no relevant pointers are contained * in the object. The nonatomic versions guarantee that the new object * is cleared. GC_malloc_stubborn promises that no changes to the object * will occur after GC_end_stubborn_change has been called on the * result of GC_malloc_stubborn. GC_malloc_uncollectable allocates an object * that is scanned for pointers to collectable objects, but is not itself * collectable. The object is scanned even if it does not appear to * be reachable. GC_malloc_uncollectable and GC_free called on the resulting * object implicitly update GC_non_gc_bytes appropriately. * * Note that the GC_malloc_stubborn support is stubbed out by default * starting in 6.0. GC_malloc_stubborn is an alias for GC_malloc unless * the collector is built with STUBBORN_ALLOC defined. */ GC_API GC_PTR GC_malloc GC_PROTO((size_t size_in_bytes)); GC_API GC_PTR GC_malloc_atomic GC_PROTO((size_t size_in_bytes)); GC_API GC_PTR GC_malloc_uncollectable GC_PROTO((size_t size_in_bytes)); GC_API GC_PTR GC_malloc_stubborn GC_PROTO((size_t size_in_bytes)); /* The following is only defined if the library has been suitably */ /* compiled: */ GC_API GC_PTR GC_malloc_atomic_uncollectable GC_PROTO((size_t size_in_bytes)); /* Explicitly deallocate an object. Dangerous if used incorrectly. */ /* Requires a pointer to the base of an object. */ /* If the argument is stubborn, it should not be changeable when freed. */ /* An object should not be enable for finalization when it is */ /* explicitly deallocated. */ /* GC_free(0) is a no-op, as required by ANSI C for free. */ GC_API void GC_free GC_PROTO((GC_PTR object_addr)); /* * Stubborn objects may be changed only if the collector is explicitly informed. * The collector is implicitly informed of coming change when such * an object is first allocated. The following routines inform the * collector that an object will no longer be changed, or that it will * once again be changed. Only nonNIL pointer stores into the object * are considered to be changes. The argument to GC_end_stubborn_change * must be exacly the value returned by GC_malloc_stubborn or passed to * GC_change_stubborn. (In the second case it may be an interior pointer * within 512 bytes of the beginning of the objects.) * There is a performance penalty for allowing more than * one stubborn object to be changed at once, but it is acceptable to * do so. The same applies to dropping stubborn objects that are still * changeable. */ GC_API void GC_change_stubborn GC_PROTO((GC_PTR)); GC_API void GC_end_stubborn_change GC_PROTO((GC_PTR)); /* Return a pointer to the base (lowest address) of an object given */ /* a pointer to a location within the object. */ /* Return 0 if displaced_pointer doesn't point to within a valid */ /* object. */ GC_API GC_PTR GC_base GC_PROTO((GC_PTR displaced_pointer)); /* Given a pointer to the base of an object, return its size in bytes. */ /* The returned size may be slightly larger than what was originally */ /* requested. */ GC_API size_t GC_size GC_PROTO((GC_PTR object_addr)); /* For compatibility with C library. This is occasionally faster than */ /* a malloc followed by a bcopy. But if you rely on that, either here */ /* or with the standard C library, your code is broken. In my */ /* opinion, it shouldn't have been invented, but now we're stuck. -HB */ /* The resulting object has the same kind as the original. */ /* If the argument is stubborn, the result will have changes enabled. */ /* It is an error to have changes enabled for the original object. */ /* Follows ANSI comventions for NULL old_object. */ GC_API GC_PTR GC_realloc GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes)); /* Explicitly increase the heap size. */ /* Returns 0 on failure, 1 on success. */ GC_API int GC_expand_hp GC_PROTO((size_t number_of_bytes)); /* Limit the heap size to n bytes. Useful when you're debugging, */ /* especially on systems that don't handle running out of memory well. */ /* n == 0 ==> unbounded. This is the default. */ GC_API void GC_set_max_heap_size GC_PROTO((GC_word n)); /* Inform the collector that a certain section of statically allocated */ /* memory contains no pointers to garbage collected memory. Thus it */ /* need not be scanned. This is sometimes important if the application */ /* maps large read/write files into the address space, which could be */ /* mistaken for dynamic library data segments on some systems. */ GC_API void GC_exclude_static_roots GC_PROTO((GC_PTR start, GC_PTR finish)); /* Clear the set of root segments. Wizards only. */ GC_API void GC_clear_roots GC_PROTO((void)); /* Add a root segment. Wizards only. */ GC_API void GC_add_roots GC_PROTO((char * low_address, char * high_address_plus_1)); /* Add a displacement to the set of those considered valid by the */ /* collector. GC_register_displacement(n) means that if p was returned */ /* by GC_malloc, then (char *)p + n will be considered to be a valid */ /* pointer to n. N must be small and less than the size of p. */ /* (All pointers to the interior of objects from the stack are */ /* considered valid in any case. This applies to heap objects and */ /* static data.) */ /* Preferably, this should be called before any other GC procedures. */ /* Calling it later adds to the probability of excess memory */ /* retention. */ /* This is a no-op if the collector was compiled with recognition of */ /* arbitrary interior pointers enabled, which is now the default. */ GC_API void GC_register_displacement GC_PROTO((GC_word n)); /* The following version should be used if any debugging allocation is */ /* being done. */ GC_API void GC_debug_register_displacement GC_PROTO((GC_word n)); /* Explicitly trigger a full, world-stop collection. */ GC_API void GC_gcollect GC_PROTO((void)); /* Trigger a full world-stopped collection. Abort the collection if */ /* and when stop_func returns a nonzero value. Stop_func will be */ /* called frequently, and should be reasonably fast. This works even */ /* if virtual dirty bits, and hence incremental collection is not */ /* available for this architecture. Collections can be aborted faster */ /* than normal pause times for incremental collection. However, */ /* aborted collections do no useful work; the next collection needs */ /* to start from the beginning. */ /* Return 0 if the collection was aborted, 1 if it succeeded. */ typedef int (* GC_stop_func) GC_PROTO((void)); GC_API int GC_try_to_collect GC_PROTO((GC_stop_func stop_func)); /* Return the number of bytes in the heap. Excludes collector private */ /* data structures. Includes empty blocks and fragmentation loss. */ /* Includes some pages that were allocated but never written. */ GC_API size_t GC_get_heap_size GC_PROTO((void)); /* Return a lower bound on the number of free bytes in the heap. */ GC_API size_t GC_get_free_bytes GC_PROTO((void)); /* Return the number of bytes allocated since the last collection. */ GC_API size_t GC_get_bytes_since_gc GC_PROTO((void)); /* Return the total number of bytes allocated in this process. */ /* Never decreases. */ GC_API size_t GC_get_total_bytes GC_PROTO((void)); /* Enable incremental/generational collection. */ /* Not advisable unless dirty bits are */ /* available or most heap objects are */ /* pointerfree(atomic) or immutable. */ /* Don't use in leak finding mode. */ /* Ignored if GC_dont_gc is true. */ /* Only the generational piece of this is */ /* functional if GC_parallel is TRUE. */ GC_API void GC_enable_incremental GC_PROTO((void)); /* Perform some garbage collection work, if appropriate. */ /* Return 0 if there is no more work to be done. */ /* Typically performs an amount of work corresponding roughly */ /* to marking from one page. May do more work if further */ /* progress requires it, e.g. if incremental collection is */ /* disabled. It is reasonable to call this in a wait loop */ /* until it returns 0. */ GC_API int GC_collect_a_little GC_PROTO((void)); /* Allocate an object of size lb bytes. The client guarantees that */ /* as long as the object is live, it will be referenced by a pointer */ /* that points to somewhere within the first 256 bytes of the object. */ /* (This should normally be declared volatile to prevent the compiler */ /* from invalidating this assertion.) This routine is only useful */ /* if a large array is being allocated. It reduces the chance of */ /* accidentally retaining such an array as a result of scanning an */ /* integer that happens to be an address inside the array. (Actually, */ /* it reduces the chance of the allocator not finding space for such */ /* an array, since it will try hard to avoid introducing such a false */ /* reference.) On a SunOS 4.X or MS Windows system this is recommended */ /* for arrays likely to be larger than 100K or so. For other systems, */ /* or if the collector is not configured to recognize all interior */ /* pointers, the threshold is normally much higher. */ GC_API GC_PTR GC_malloc_ignore_off_page GC_PROTO((size_t lb)); GC_API GC_PTR GC_malloc_atomic_ignore_off_page GC_PROTO((size_t lb)); #if defined(__sgi) && !defined(__GNUC__) && _COMPILER_VERSION >= 720 # define GC_ADD_CALLER # define GC_RETURN_ADDR (GC_word)__return_address #endif #ifdef GC_ADD_CALLER # define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__ # define GC_EXTRA_PARAMS GC_word ra, GC_CONST char * s, int i #else # define GC_EXTRAS __FILE__, __LINE__ # define GC_EXTRA_PARAMS GC_CONST char * s, int i #endif /* Debugging (annotated) allocation. GC_gcollect will check */ /* objects allocated in this way for overwrites, etc. */ GC_API GC_PTR GC_debug_malloc GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS)); GC_API GC_PTR GC_debug_malloc_atomic GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS)); GC_API GC_PTR GC_debug_malloc_uncollectable GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS)); GC_API GC_PTR GC_debug_malloc_stubborn GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS)); GC_API void GC_debug_free GC_PROTO((GC_PTR object_addr)); GC_API GC_PTR GC_debug_realloc GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes, GC_EXTRA_PARAMS)); GC_API void GC_debug_change_stubborn GC_PROTO((GC_PTR)); GC_API void GC_debug_end_stubborn_change GC_PROTO((GC_PTR)); # ifdef GC_DEBUG # define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS) # define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS) # define GC_MALLOC_UNCOLLECTABLE(sz) GC_debug_malloc_uncollectable(sz, \ GC_EXTRAS) # define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, GC_EXTRAS) # define GC_FREE(p) GC_debug_free(p) # define GC_REGISTER_FINALIZER(p, f, d, of, od) \ GC_debug_register_finalizer(p, f, d, of, od) # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \ GC_debug_register_finalizer_ignore_self(p, f, d, of, od) # define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \ GC_debug_register_finalizer_no_order(p, f, d, of, od) # define GC_MALLOC_STUBBORN(sz) GC_debug_malloc_stubborn(sz, GC_EXTRAS); # define GC_CHANGE_STUBBORN(p) GC_debug_change_stubborn(p) # define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p) # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \ GC_general_register_disappearing_link(link, GC_base(obj)) # define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n) # else # define GC_MALLOC(sz) GC_malloc(sz) # define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz) # define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz) # define GC_REALLOC(old, sz) GC_realloc(old, sz) # define GC_FREE(p) GC_free(p) # define GC_REGISTER_FINALIZER(p, f, d, of, od) \ GC_register_finalizer(p, f, d, of, od) # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \ GC_register_finalizer_ignore_self(p, f, d, of, od) # define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \ GC_register_finalizer_no_order(p, f, d, of, od) # define GC_MALLOC_STUBBORN(sz) GC_malloc_stubborn(sz) # define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p) # define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p) # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \ GC_general_register_disappearing_link(link, obj) # define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n) # endif /* The following are included because they are often convenient, and */ /* reduce the chance for a misspecifed size argument. But calls may */ /* expand to something syntactically incorrect if t is a complicated */ /* type expression. */ # define GC_NEW(t) (t *)GC_MALLOC(sizeof (t)) # define GC_NEW_ATOMIC(t) (t *)GC_MALLOC_ATOMIC(sizeof (t)) # define GC_NEW_STUBBORN(t) (t *)GC_MALLOC_STUBBORN(sizeof (t)) # define GC_NEW_UNCOLLECTABLE(t) (t *)GC_MALLOC_UNCOLLECTABLE(sizeof (t)) /* Finalization. Some of these primitives are grossly unsafe. */ /* The idea is to make them both cheap, and sufficient to build */ /* a safer layer, closer to PCedar finalization. */ /* The interface represents my conclusions from a long discussion */ /* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes, */ /* Christian Jacobi, and Russ Atkinson. It's not perfect, and */ /* probably nobody else agrees with it. Hans-J. Boehm 3/13/92 */ typedef void (*GC_finalization_proc) GC_PROTO((GC_PTR obj, GC_PTR client_data)); GC_API void GC_register_finalizer GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd, GC_finalization_proc *ofn, GC_PTR *ocd)); GC_API void GC_debug_register_finalizer GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd, GC_finalization_proc *ofn, GC_PTR *ocd)); /* When obj is no longer accessible, invoke */ /* (*fn)(obj, cd). If a and b are inaccessible, and */ /* a points to b (after disappearing links have been */ /* made to disappear), then only a will be */ /* finalized. (If this does not create any new */ /* pointers to b, then b will be finalized after the */ /* next collection.) Any finalizable object that */ /* is reachable from itself by following one or more */ /* pointers will not be finalized (or collected). */ /* Thus cycles involving finalizable objects should */ /* be avoided, or broken by disappearing links. */ /* All but the last finalizer registered for an object */ /* is ignored. */ /* Finalization may be removed by passing 0 as fn. */ /* Finalizers are implicitly unregistered just before */ /* they are invoked. */ /* The old finalizer and client data are stored in */ /* *ofn and *ocd. */ /* Fn is never invoked on an accessible object, */ /* provided hidden pointers are converted to real */ /* pointers only if the allocation lock is held, and */ /* such conversions are not performed by finalization */ /* routines. */ /* If GC_register_finalizer is aborted as a result of */ /* a signal, the object may be left with no */ /* finalization, even if neither the old nor new */ /* finalizer were NULL. */ /* Obj should be the nonNULL starting address of an */ /* object allocated by GC_malloc or friends. */ /* Note that any garbage collectable object referenced */ /* by cd will be considered accessible until the */ /* finalizer is invoked. */ /* Another versions of the above follow. It ignores */ /* self-cycles, i.e. pointers from a finalizable object to */ /* itself. There is a stylistic argument that this is wrong, */ /* but it's unavoidable for C++, since the compiler may */ /* silently introduce these. It's also benign in that specific */ /* case. */ /* Note that cd will still be viewed as accessible, even if it */ /* refers to the object itself. */ GC_API void GC_register_finalizer_ignore_self GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd, GC_finalization_proc *ofn, GC_PTR *ocd)); GC_API void GC_debug_register_finalizer_ignore_self GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd, GC_finalization_proc *ofn, GC_PTR *ocd)); /* Another version of the above. It ignores all cycles. */ /* It should probably only be used by Java implementations. */ /* Note that cd will still be viewed as accessible, even if it */ /* refers to the object itself. */ GC_API void GC_register_finalizer_no_order GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd, GC_finalization_proc *ofn, GC_PTR *ocd)); GC_API void GC_debug_register_finalizer_no_order GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd, GC_finalization_proc *ofn, GC_PTR *ocd)); /* The following routine may be used to break cycles between */ /* finalizable objects, thus causing cyclic finalizable */ /* objects to be finalized in the correct order. Standard */ /* use involves calling GC_register_disappearing_link(&p), */ /* where p is a pointer that is not followed by finalization */ /* code, and should not be considered in determining */ /* finalization order. */ GC_API int GC_register_disappearing_link GC_PROTO((GC_PTR * /* link */)); /* Link should point to a field of a heap allocated */ /* object obj. *link will be cleared when obj is */ /* found to be inaccessible. This happens BEFORE any */ /* finalization code is invoked, and BEFORE any */ /* decisions about finalization order are made. */ /* This is useful in telling the finalizer that */ /* some pointers are not essential for proper */ /* finalization. This may avoid finalization cycles. */ /* Note that obj may be resurrected by another */ /* finalizer, and thus the clearing of *link may */ /* be visible to non-finalization code. */ /* There's an argument that an arbitrary action should */ /* be allowed here, instead of just clearing a pointer. */ /* But this causes problems if that action alters, or */ /* examines connectivity. */ /* Returns 1 if link was already registered, 0 */ /* otherwise. */ /* Only exists for backward compatibility. See below: */ GC_API int GC_general_register_disappearing_link GC_PROTO((GC_PTR * /* link */, GC_PTR obj)); /* A slight generalization of the above. *link is */ /* cleared when obj first becomes inaccessible. This */ /* can be used to implement weak pointers easily and */ /* safely. Typically link will point to a location */ /* holding a disguised pointer to obj. (A pointer */ /* inside an "atomic" object is effectively */ /* disguised.) In this way soft */ /* pointers are broken before any object */ /* reachable from them are finalized. Each link */ /* May be registered only once, i.e. with one obj */ /* value. This was added after a long email discussion */ /* with John Ellis. */ /* Obj must be a pointer to the first word of an object */ /* we allocated. It is unsafe to explicitly deallocate */ /* the object containing link. Explicitly deallocating */ /* obj may or may not cause link to eventually be */ /* cleared. */ GC_API int GC_unregister_disappearing_link GC_PROTO((GC_PTR * /* link */)); /* Returns 0 if link was not actually registered. */ /* Undoes a registration by either of the above two */ /* routines. */ /* Auxiliary fns to make finalization work correctly with displaced */ /* pointers introduced by the debugging allocators. */ GC_API GC_PTR GC_make_closure GC_PROTO((GC_finalization_proc fn, GC_PTR data)); GC_API void GC_debug_invoke_finalizer GC_PROTO((GC_PTR obj, GC_PTR data)); /* Returns !=0 if GC_invoke_finalizers has something to do. */ GC_API int GC_should_invoke_finalizers GC_PROTO((void)); GC_API int GC_invoke_finalizers GC_PROTO((void)); /* Run finalizers for all objects that are ready to */ /* be finalized. Return the number of finalizers */ /* that were run. Normally this is also called */ /* implicitly during some allocations. If */ /* GC-finalize_on_demand is nonzero, it must be called */ /* explicitly. */ /* GC_set_warn_proc can be used to redirect or filter warning messages. */ /* p may not be a NULL pointer. */ typedef void (*GC_warn_proc) GC_PROTO((char *msg, GC_word arg)); GC_API GC_warn_proc GC_set_warn_proc GC_PROTO((GC_warn_proc p)); /* Returns old warning procedure. */ /* The following is intended to be used by a higher level */ /* (e.g. Java-like) finalization facility. It is expected */ /* that finalization code will arrange for hidden pointers to */ /* disappear. Otherwise objects can be accessed after they */ /* have been collected. */ /* Note that putting pointers in atomic objects or in */ /* nonpointer slots of "typed" objects is equivalent to */ /* disguising them in this way, and may have other advantages. */ # if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS) typedef GC_word GC_hidden_pointer; # define HIDE_POINTER(p) (~(GC_hidden_pointer)(p)) # define REVEAL_POINTER(p) ((GC_PTR)(HIDE_POINTER(p))) /* Converting a hidden pointer to a real pointer requires verifying */ /* that the object still exists. This involves acquiring the */ /* allocator lock to avoid a race with the collector. */ # endif /* I_HIDE_POINTERS */ typedef GC_PTR (*GC_fn_type) GC_PROTO((GC_PTR client_data)); GC_API GC_PTR GC_call_with_alloc_lock GC_PROTO((GC_fn_type fn, GC_PTR client_data)); /* The following routines are primarily intended for use with a */ /* preprocessor which inserts calls to check C pointer arithmetic. */ /* Check that p and q point to the same object. */ /* Fail conspicuously if they don't. */ /* Returns the first argument. */ /* Succeeds if neither p nor q points to the heap. */ /* May succeed if both p and q point to between heap objects. */ GC_API GC_PTR GC_same_obj GC_PROTO((GC_PTR p, GC_PTR q)); /* Checked pointer pre- and post- increment operations. Note that */ /* the second argument is in units of bytes, not multiples of the */ /* object size. This should either be invoked from a macro, or the */ /* call should be automatically generated. */ GC_API GC_PTR GC_pre_incr GC_PROTO((GC_PTR *p, size_t how_much)); GC_API GC_PTR GC_post_incr GC_PROTO((GC_PTR *p, size_t how_much)); /* Check that p is visible */ /* to the collector as a possibly pointer containing location. */ /* If it isn't fail conspicuously. */ /* Returns the argument in all cases. May erroneously succeed */ /* in hard cases. (This is intended for debugging use with */ /* untyped allocations. The idea is that it should be possible, though */ /* slow, to add such a call to all indirect pointer stores.) */ /* Currently useless for multithreaded worlds. */ GC_API GC_PTR GC_is_visible GC_PROTO((GC_PTR p)); /* Check that if p is a pointer to a heap page, then it points to */ /* a valid displacement within a heap object. */ /* Fail conspicuously if this property does not hold. */ /* Uninteresting with GC_all_interior_pointers. */ /* Always returns its argument. */ GC_API GC_PTR GC_is_valid_displacement GC_PROTO((GC_PTR p)); /* Safer, but slow, pointer addition. Probably useful mainly with */ /* a preprocessor. Useful only for heap pointers. */ #ifdef GC_DEBUG # define GC_PTR_ADD3(x, n, type_of_result) \ ((type_of_result)GC_same_obj((x)+(n), (x))) # define GC_PRE_INCR3(x, n, type_of_result) \ ((type_of_result)GC_pre_incr(&(x), (n)*sizeof(*x)) # define GC_POST_INCR2(x, type_of_result) \ ((type_of_result)GC_post_incr(&(x), sizeof(*x)) # ifdef __GNUC__ # define GC_PTR_ADD(x, n) \ GC_PTR_ADD3(x, n, typeof(x)) # define GC_PRE_INCR(x, n) \ GC_PRE_INCR3(x, n, typeof(x)) # define GC_POST_INCR(x, n) \ GC_POST_INCR3(x, typeof(x)) # else /* We can't do this right without typeof, which ANSI */ /* decided was not sufficiently useful. Repeatedly */ /* mentioning the arguments seems too dangerous to be */ /* useful. So does not casting the result. */ # define GC_PTR_ADD(x, n) ((x)+(n)) # endif #else /* !GC_DEBUG */ # define GC_PTR_ADD3(x, n, type_of_result) ((x)+(n)) # define GC_PTR_ADD(x, n) ((x)+(n)) # define GC_PRE_INCR3(x, n, type_of_result) ((x) += (n)) # define GC_PRE_INCR(x, n) ((x) += (n)) # define GC_POST_INCR2(x, n, type_of_result) ((x)++) # define GC_POST_INCR(x, n) ((x)++) #endif /* Safer assignment of a pointer to a nonstack location. */ #ifdef GC_DEBUG # ifdef __STDC__ # define GC_PTR_STORE(p, q) \ (*(void **)GC_is_visible(p) = GC_is_valid_displacement(q)) # else # define GC_PTR_STORE(p, q) \ (*(char **)GC_is_visible(p) = GC_is_valid_displacement(q)) # endif #else /* !GC_DEBUG */ # define GC_PTR_STORE(p, q) *((p) = (q)) #endif /* Fynctions called to report pointer checking errors */ GC_API void (*GC_same_obj_print_proc) GC_PROTO((GC_PTR p, GC_PTR q)); GC_API void (*GC_is_valid_displacement_print_proc) GC_PROTO((GC_PTR p)); GC_API void (*GC_is_visible_print_proc) GC_PROTO((GC_PTR p)); /* For pthread support, we generally need to intercept a number of */ /* thread library calls. We do that here by macro defining them. */ #if !defined(GC_USE_LD_WRAP) && \ (defined(GC_LINUX_THREADS) || defined(GC_HPUX_THREADS) || \ defined(GC_IRIX_THREADS) || defined(GC_SOLARIS_PTHREADS) || \ defined(GC_SOLARIS_THREADS) || defined(GC_OSF1_THREADS)) # include "gc_pthread_redirects.h" #endif # if defined(PCR) || defined(GC_SOLARIS_THREADS) || \ defined(GC_SOLARIS_PTHREADS) || defined(GC_WIN32_THREADS) || \ defined(GC_IRIX_THREADS) || defined(GC_LINUX_THREADS) || \ defined(GC_HPUX_THREADS) /* Any flavor of threads except SRC_M3. */ /* This returns a list of objects, linked through their first */ /* word. Its use can greatly reduce lock contention problems, since */ /* the allocation lock can be acquired and released many fewer times. */ /* lb must be large enough to hold the pointer field. */ /* It is used internally by gc_local_alloc.h, which provides a simpler */ /* programming interface on Linux. */ GC_PTR GC_malloc_many(size_t lb); #define GC_NEXT(p) (*(GC_PTR *)(p)) /* Retrieve the next element */ /* in returned list. */ extern void GC_thr_init(); /* Needed for Solaris/X86 */ #endif /* THREADS && !SRC_M3 */ #if defined(WIN32_THREADS) && defined(_WIN32_WCE) # include <windows.h> /* * win32_threads.c implements the real WinMain, which will start a new thread * to call GC_WinMain after initializing the garbage collector. */ int WINAPI GC_WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPWSTR lpCmdLine, int nCmdShow ); /* * All threads must be created using GC_CreateThread, so that they will be * recorded in the thread table. */ HANDLE WINAPI GC_CreateThread( LPSECURITY_ATTRIBUTES lpThreadAttributes, DWORD dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress, LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId ); # ifndef GC_BUILD # define WinMain GC_WinMain # define CreateThread GC_CreateThread # endif #endif /* * If you are planning on putting * the collector in a SunOS 5 dynamic library, you need to call GC_INIT() * from the statically loaded program section. * This circumvents a Solaris 2.X (X<=4) linker bug. */ #if defined(sparc) || defined(__sparc) # define GC_INIT() { extern end, etext; \ GC_noop(&end, &etext); } #else # if defined(__CYGWIN32__) && defined(GC_USE_DLL) /* * Similarly gnu-win32 DLLs need explicit initialization */ # define GC_INIT() { GC_add_roots(DATASTART, DATAEND); } # else # define GC_INIT() # endif #endif #if !defined(_WIN32_WCE) \ && ((defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \ || defined(_WIN32) && !defined(__CYGWIN32__) && !defined(__CYGWIN__)) /* win32S may not free all resources on process exit. */ /* This explicitly deallocates the heap. */ GC_API void GC_win32_free_heap (); #endif #if ( defined(_AMIGA) && !defined(GC_AMIGA_MAKINGLIB) ) /* Allocation really goes through GC_amiga_allocwrapper_do */ # include "gc_amiga_redirects.h" #endif #if defined(GC_REDIRECT_TO_LOCAL) && !defined(GC_LOCAL_ALLOC_H) # include "gc_local_alloc.h" #endif #ifdef __cplusplus } /* end of extern "C" */ #endif #endif /* _GC_H */