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| -rw-r--r-- | gc/gc.h | 754 |
1 files changed, 754 insertions, 0 deletions
@@ -0,0 +1,754 @@ +/* + * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers + * Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. + * Copyright 1996 by Silicon Graphics. 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 +# define __GC +# include <stddef.h> + +#if defined(__CYGWIN32__) && defined(GC_USE_DLL) +#include "libgc_globals.h" +#endif + +#if defined(_MSC_VER) && defined(_DLL) +# ifdef GC_BUILD +# define GC_API __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; +# else +# define GC_PROTO(args) () + typedef char * GC_PTR; +# 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. */ + + +/* 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_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 eplit 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 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_full_freq; /* Number of partial collections between */ + /* full collections. Matters only if */ + /* GC_incremental is set. */ + +GC_API GC_word GC_non_gc_bytes; + /* Bytes not considered candidates for collection. */ + /* Used only to control scheduling of collections. */ + +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. */ + +/* 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. GC_malloc_uncollectable and GC_free called on the resulting + * object implicitly update GC_non_gc_bytes appropriately. + */ +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 the number of bytes allocated since the last collection. */ +GC_API size_t GC_get_bytes_since_gc 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. */ +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, char * descr_string, int descr_int +#else +# define GC_EXTRAS __FILE__, __LINE__ +# define GC_EXTRA_PARAMS char * descr_string, int descr_int +#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_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_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. */ +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)); + +/* 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)); + +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. cedar-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)); + +/* 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 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)); + +#if defined(_SOLARIS_PTHREADS) && !defined(SOLARIS_THREADS) +# define SOLARIS_THREADS +#endif + +#ifdef SOLARIS_THREADS +/* We need to intercept calls to many of the threads primitives, so */ +/* that we can locate thread stacks and stop the world. */ +/* Note also that the collector cannot see thread specific data. */ +/* Thread specific data should generally consist of pointers to */ +/* uncollectable objects, which are deallocated using the destructor */ +/* facility in thr_keycreate. */ +# include <thread.h> +# include <signal.h> + int GC_thr_create(void *stack_base, size_t stack_size, + void *(*start_routine)(void *), void *arg, long flags, + thread_t *new_thread); + int GC_thr_join(thread_t wait_for, thread_t *departed, void **status); + int GC_thr_suspend(thread_t target_thread); + int GC_thr_continue(thread_t target_thread); + void * GC_dlopen(const char *path, int mode); + +# ifdef _SOLARIS_PTHREADS +# include <pthread.h> + extern int GC_pthread_create(pthread_t *new_thread, + const pthread_attr_t *attr, + void * (*thread_execp)(void *), void *arg); + extern int GC_pthread_join(pthread_t wait_for, void **status); + +# undef thread_t + +# define pthread_join GC_pthread_join +# define pthread_create GC_pthread_create +#endif + +# define thr_create GC_thr_create +# define thr_join GC_thr_join +# define thr_suspend GC_thr_suspend +# define thr_continue GC_thr_continue +# define dlopen GC_dlopen + +# endif /* SOLARIS_THREADS */ + + +#if defined(IRIX_THREADS) || defined(LINUX_THREADS) +/* We treat these similarly. */ +# include <pthread.h> +# include <signal.h> + + int GC_pthread_create(pthread_t *new_thread, + const pthread_attr_t *attr, + void *(*start_routine)(void *), void *arg); + int GC_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset); + int GC_pthread_join(pthread_t thread, void **retval); + +# define pthread_create GC_pthread_create +# define pthread_sigmask GC_pthread_sigmask +# define pthread_join GC_pthread_join + +#endif /* IRIX_THREADS || LINUX_THREADS */ + +# if defined(PCR) || defined(SOLARIS_THREADS) || defined(WIN32_THREADS) || \ + defined(IRIX_THREADS) || defined(LINUX_THREADS) || \ + defined(IRIX_JDK_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. */ +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 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(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \ + || defined(_WIN32) + /* win32S may not free all resources on process exit. */ + /* This explicitly deallocates the heap. */ + GC_API void GC_win32_free_heap (); +#endif + +#ifdef __cplusplus + } /* end of extern "C" */ +#endif + +#endif /* _GC_H */ |