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/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1996 by Xerox Corporation. All rights reserved.
* Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved.
* Copyright (C) 2007 Free Software Foundation, Inc
* 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.
*/
#include "private/gc_pmark.h"
#ifndef GC_NO_FINALIZATION
/* Type of mark procedure used for marking from finalizable object. */
/* This procedure normally does not mark the object, only its */
/* descendants. */
typedef void (* finalization_mark_proc)(ptr_t /* finalizable_obj_ptr */);
#define HASH3(addr,size,log_size) \
((((word)(addr) >> 3) ^ ((word)(addr) >> (3 + (log_size)))) \
& ((size) - 1))
#define HASH2(addr,log_size) HASH3(addr, 1 << (log_size), log_size)
struct hash_chain_entry {
word hidden_key;
struct hash_chain_entry * next;
};
struct disappearing_link {
struct hash_chain_entry prolog;
# define dl_hidden_link prolog.hidden_key
/* Field to be cleared. */
# define dl_next(x) (struct disappearing_link *)((x) -> prolog.next)
# define dl_set_next(x, y) \
(void)((x)->prolog.next = (struct hash_chain_entry *)(y))
word dl_hidden_obj; /* Pointer to object base */
};
struct dl_hashtbl_s {
struct disappearing_link **head;
signed_word log_size;
word entries;
};
STATIC struct dl_hashtbl_s GC_dl_hashtbl = {
/* head */ NULL, /* log_size */ -1, /* entries */ 0 };
#ifndef GC_LONG_REFS_NOT_NEEDED
STATIC struct dl_hashtbl_s GC_ll_hashtbl = { NULL, -1, 0 };
#endif
STATIC struct finalizable_object {
struct hash_chain_entry prolog;
# define fo_hidden_base prolog.hidden_key
/* Pointer to object base. */
/* No longer hidden once object */
/* is on finalize_now queue. */
# define fo_next(x) (struct finalizable_object *)((x) -> prolog.next)
# define fo_set_next(x,y) ((x)->prolog.next = (struct hash_chain_entry *)(y))
GC_finalization_proc fo_fn; /* Finalizer. */
ptr_t fo_client_data;
word fo_object_size; /* In bytes. */
finalization_mark_proc fo_mark_proc; /* Mark-through procedure */
} **GC_fo_head = 0;
STATIC struct finalizable_object * GC_finalize_now = 0;
/* List of objects that should be finalized now. */
static signed_word log_fo_table_size = -1;
GC_INNER void GC_push_finalizer_structures(void)
{
GC_ASSERT((word)&GC_dl_hashtbl.head % sizeof(word) == 0);
GC_ASSERT((word)&GC_fo_head % sizeof(word) == 0);
GC_ASSERT((word)&GC_finalize_now % sizeof(word) == 0);
# ifndef GC_LONG_REFS_NOT_NEEDED
GC_ASSERT((word)&GC_ll_hashtbl.head % sizeof(word) == 0);
GC_push_all((ptr_t)(&GC_ll_hashtbl.head),
(ptr_t)(&GC_ll_hashtbl.head) + sizeof(word));
# endif
GC_push_all((ptr_t)(&GC_dl_hashtbl.head),
(ptr_t)(&GC_dl_hashtbl.head) + sizeof(word));
GC_push_all((ptr_t)(&GC_fo_head), (ptr_t)(&GC_fo_head) + sizeof(word));
GC_push_all((ptr_t)(&GC_finalize_now),
(ptr_t)(&GC_finalize_now) + sizeof(word));
}
/* Double the size of a hash table. *size_ptr is the log of its current */
/* size. May be a no-op. */
/* *table is a pointer to an array of hash headers. If we succeed, we */
/* update both *table and *log_size_ptr. Lock is held. */
STATIC void GC_grow_table(struct hash_chain_entry ***table,
signed_word *log_size_ptr)
{
register word i;
register struct hash_chain_entry *p;
signed_word log_old_size = *log_size_ptr;
signed_word log_new_size = log_old_size + 1;
word old_size = ((log_old_size == -1)? 0: (1 << log_old_size));
word new_size = (word)1 << log_new_size;
/* FIXME: Power of 2 size often gets rounded up to one more page. */
struct hash_chain_entry **new_table = (struct hash_chain_entry **)
GC_INTERNAL_MALLOC_IGNORE_OFF_PAGE(
(size_t)new_size * sizeof(struct hash_chain_entry *), NORMAL);
if (new_table == 0) {
if (*table == 0) {
ABORT("Insufficient space for initial table allocation");
} else {
return;
}
}
for (i = 0; i < old_size; i++) {
p = (*table)[i];
while (p != 0) {
ptr_t real_key = GC_REVEAL_POINTER(p -> hidden_key);
struct hash_chain_entry *next = p -> next;
size_t new_hash = HASH3(real_key, new_size, log_new_size);
p -> next = new_table[new_hash];
new_table[new_hash] = p;
p = next;
}
}
*log_size_ptr = log_new_size;
*table = new_table;
}
GC_API int GC_CALL GC_register_disappearing_link(void * * link)
{
ptr_t base;
base = (ptr_t)GC_base(link);
if (base == 0)
ABORT("Bad arg to GC_register_disappearing_link");
return(GC_general_register_disappearing_link(link, base));
}
STATIC int GC_register_disappearing_link_inner(
struct dl_hashtbl_s *dl_hashtbl, void **link,
const void *obj)
{
struct disappearing_link *curr_dl;
size_t index;
struct disappearing_link * new_dl;
DCL_LOCK_STATE;
LOCK();
GC_ASSERT(obj != NULL && GC_base_C(obj) == obj);
if (dl_hashtbl -> log_size == -1
|| dl_hashtbl -> entries > ((word)1 << dl_hashtbl -> log_size)) {
GC_grow_table((struct hash_chain_entry ***)&dl_hashtbl -> head,
&dl_hashtbl -> log_size);
GC_COND_LOG_PRINTF("Grew dl table to %u entries\n",
1 << (unsigned)dl_hashtbl -> log_size);
}
index = HASH2(link, dl_hashtbl -> log_size);
for (curr_dl = dl_hashtbl -> head[index]; curr_dl != 0;
curr_dl = dl_next(curr_dl)) {
if (curr_dl -> dl_hidden_link == GC_HIDE_POINTER(link)) {
curr_dl -> dl_hidden_obj = GC_HIDE_POINTER(obj);
UNLOCK();
return GC_DUPLICATE;
}
}
new_dl = (struct disappearing_link *)
GC_INTERNAL_MALLOC(sizeof(struct disappearing_link),NORMAL);
if (0 == new_dl) {
GC_oom_func oom_fn = GC_oom_fn;
UNLOCK();
new_dl = (struct disappearing_link *)
(*oom_fn)(sizeof(struct disappearing_link));
if (0 == new_dl) {
return GC_NO_MEMORY;
}
/* It's not likely we'll make it here, but ... */
LOCK();
/* Recalculate index since the table may grow. */
index = HASH2(link, dl_hashtbl -> log_size);
/* Check again that our disappearing link not in the table. */
for (curr_dl = dl_hashtbl -> head[index]; curr_dl != 0;
curr_dl = dl_next(curr_dl)) {
if (curr_dl -> dl_hidden_link == GC_HIDE_POINTER(link)) {
curr_dl -> dl_hidden_obj = GC_HIDE_POINTER(obj);
UNLOCK();
# ifndef DBG_HDRS_ALL
/* Free unused new_dl returned by GC_oom_fn() */
GC_free((void *)new_dl);
# endif
return GC_DUPLICATE;
}
}
}
new_dl -> dl_hidden_obj = GC_HIDE_POINTER(obj);
new_dl -> dl_hidden_link = GC_HIDE_POINTER(link);
dl_set_next(new_dl, dl_hashtbl -> head[index]);
dl_hashtbl -> head[index] = new_dl;
dl_hashtbl -> entries++;
UNLOCK();
return GC_SUCCESS;
}
GC_API int GC_CALL GC_general_register_disappearing_link(void * * link,
const void * obj)
{
if (((word)link & (ALIGNMENT-1)) != 0 || NULL == link)
ABORT("Bad arg to GC_general_register_disappearing_link");
return GC_register_disappearing_link_inner(&GC_dl_hashtbl, link, obj);
}
#ifdef DBG_HDRS_ALL
# define FREE_DL_ENTRY(curr_dl) dl_set_next(curr_dl, NULL)
#else
# define FREE_DL_ENTRY(curr_dl) GC_free(curr_dl)
#endif
/* Unregisters given link and returns the link entry to free. */
/* Assume the lock is held. */
GC_INLINE struct disappearing_link *GC_unregister_disappearing_link_inner(
struct dl_hashtbl_s *dl_hashtbl, void **link)
{
struct disappearing_link *curr_dl;
struct disappearing_link *prev_dl = NULL;
size_t index = HASH2(link, dl_hashtbl->log_size);
for (curr_dl = dl_hashtbl -> head[index]; curr_dl;
curr_dl = dl_next(curr_dl)) {
if (curr_dl -> dl_hidden_link == GC_HIDE_POINTER(link)) {
/* Remove found entry from the table. */
if (NULL == prev_dl) {
dl_hashtbl -> head[index] = dl_next(curr_dl);
} else {
dl_set_next(prev_dl, dl_next(curr_dl));
}
dl_hashtbl -> entries--;
break;
}
prev_dl = curr_dl;
}
return curr_dl;
}
GC_API int GC_CALL GC_unregister_disappearing_link(void * * link)
{
struct disappearing_link *curr_dl;
DCL_LOCK_STATE;
if (((word)link & (ALIGNMENT-1)) != 0) return(0); /* Nothing to do. */
LOCK();
curr_dl = GC_unregister_disappearing_link_inner(&GC_dl_hashtbl, link);
UNLOCK();
if (NULL == curr_dl) return 0;
FREE_DL_ENTRY(curr_dl);
return 1;
}
#ifndef GC_LONG_REFS_NOT_NEEDED
GC_API int GC_CALL GC_register_long_link(void * * link, const void * obj)
{
if (((word)link & (ALIGNMENT-1)) != 0 || NULL == link)
ABORT("Bad arg to GC_register_long_link");
return GC_register_disappearing_link_inner(&GC_ll_hashtbl, link, obj);
}
GC_API int GC_CALL GC_unregister_long_link(void * * link)
{
struct disappearing_link *curr_dl;
DCL_LOCK_STATE;
if (((word)link & (ALIGNMENT-1)) != 0) return(0); /* Nothing to do. */
LOCK();
curr_dl = GC_unregister_disappearing_link_inner(&GC_ll_hashtbl, link);
UNLOCK();
if (NULL == curr_dl) return 0;
FREE_DL_ENTRY(curr_dl);
return 1;
}
#endif /* !GC_LONG_REFS_NOT_NEEDED */
#ifndef GC_MOVE_DISAPPEARING_LINK_NOT_NEEDED
/* Moves a link. Assume the lock is held. */
STATIC int GC_move_disappearing_link_inner(
struct dl_hashtbl_s *dl_hashtbl,
void **link, void **new_link)
{
struct disappearing_link *curr_dl, *prev_dl, *new_dl;
size_t curr_index, new_index;
word curr_hidden_link;
word new_hidden_link;
/* Find current link. */
curr_index = HASH2(link, dl_hashtbl -> log_size);
curr_hidden_link = GC_HIDE_POINTER(link);
prev_dl = NULL;
for (curr_dl = dl_hashtbl -> head[curr_index]; curr_dl;
curr_dl = dl_next(curr_dl)) {
if (curr_dl -> dl_hidden_link == curr_hidden_link)
break;
prev_dl = curr_dl;
}
if (NULL == curr_dl) {
return GC_NOT_FOUND;
}
if (link == new_link) {
return GC_SUCCESS; /* Nothing to do. */
}
/* link found; now check new_link not present. */
new_index = HASH2(new_link, dl_hashtbl -> log_size);
new_hidden_link = GC_HIDE_POINTER(new_link);
for (new_dl = dl_hashtbl -> head[new_index]; new_dl;
new_dl = dl_next(new_dl)) {
if (new_dl -> dl_hidden_link == new_hidden_link) {
/* Target already registered; bail. */
return GC_DUPLICATE;
}
}
/* Remove from old, add to new, update link. */
if (NULL == prev_dl) {
dl_hashtbl -> head[curr_index] = dl_next(curr_dl);
} else {
dl_set_next(prev_dl, dl_next(curr_dl));
}
curr_dl -> dl_hidden_link = new_hidden_link;
dl_set_next(curr_dl, dl_hashtbl -> head[new_index]);
dl_hashtbl -> head[new_index] = curr_dl;
return GC_SUCCESS;
}
GC_API int GC_CALL GC_move_disappearing_link(void **link, void **new_link)
{
int result;
DCL_LOCK_STATE;
if (((word)new_link & (ALIGNMENT-1)) != 0 || new_link == NULL)
ABORT("Bad new_link arg to GC_move_disappearing_link");
if (((word)link & (ALIGNMENT-1)) != 0)
return GC_NOT_FOUND; /* Nothing to do. */
LOCK();
result = GC_move_disappearing_link_inner(&GC_dl_hashtbl, link, new_link);
UNLOCK();
return result;
}
# ifndef GC_LONG_REFS_NOT_NEEDED
GC_API int GC_CALL GC_move_long_link(void **link, void **new_link)
{
int result;
DCL_LOCK_STATE;
if (((word)new_link & (ALIGNMENT-1)) != 0 || new_link == NULL)
ABORT("Bad new_link arg to GC_move_disappearing_link");
if (((word)link & (ALIGNMENT-1)) != 0)
return GC_NOT_FOUND; /* Nothing to do. */
LOCK();
result = GC_move_disappearing_link_inner(&GC_ll_hashtbl, link, new_link);
UNLOCK();
return result;
}
# endif /* !GC_LONG_REFS_NOT_NEEDED */
#endif /* !GC_MOVE_DISAPPEARING_LINK_NOT_NEEDED */
/* Possible finalization_marker procedures. Note that mark stack */
/* overflow is handled by the caller, and is not a disaster. */
STATIC void GC_normal_finalize_mark_proc(ptr_t p)
{
hdr * hhdr = HDR(p);
PUSH_OBJ(p, hhdr, GC_mark_stack_top,
&(GC_mark_stack[GC_mark_stack_size]));
}
/* This only pays very partial attention to the mark descriptor. */
/* It does the right thing for normal and atomic objects, and treats */
/* most others as normal. */
STATIC void GC_ignore_self_finalize_mark_proc(ptr_t p)
{
hdr * hhdr = HDR(p);
word descr = hhdr -> hb_descr;
ptr_t q;
word r;
ptr_t scan_limit;
ptr_t target_limit = p + hhdr -> hb_sz - 1;
if ((descr & GC_DS_TAGS) == GC_DS_LENGTH) {
scan_limit = p + descr - sizeof(word);
} else {
scan_limit = target_limit + 1 - sizeof(word);
}
for (q = p; (word)q <= (word)scan_limit; q += ALIGNMENT) {
r = *(word *)q;
if (r < (word)p || r > (word)target_limit) {
GC_PUSH_ONE_HEAP(r, q, GC_mark_stack_top);
}
}
}
STATIC void GC_null_finalize_mark_proc(ptr_t p GC_ATTR_UNUSED) {}
/* Possible finalization_marker procedures. Note that mark stack */
/* overflow is handled by the caller, and is not a disaster. */
/* GC_unreachable_finalize_mark_proc is an alias for normal marking, */
/* but it is explicitly tested for, and triggers different */
/* behavior. Objects registered in this way are not finalized */
/* if they are reachable by other finalizable objects, even if those */
/* other objects specify no ordering. */
STATIC void GC_unreachable_finalize_mark_proc(ptr_t p)
{
GC_normal_finalize_mark_proc(p);
}
/* Register a finalization function. See gc.h for details. */
/* The last parameter is a procedure that determines */
/* marking for finalization ordering. Any objects marked */
/* by that procedure will be guaranteed to not have been */
/* finalized when this finalizer is invoked. */
STATIC void GC_register_finalizer_inner(void * obj,
GC_finalization_proc fn, void *cd,
GC_finalization_proc *ofn, void **ocd,
finalization_mark_proc mp)
{
ptr_t base;
struct finalizable_object * curr_fo, * prev_fo;
size_t index;
struct finalizable_object *new_fo = 0;
hdr *hhdr = NULL; /* initialized to prevent warning. */
GC_oom_func oom_fn;
DCL_LOCK_STATE;
LOCK();
if (log_fo_table_size == -1
|| GC_fo_entries > ((word)1 << log_fo_table_size)) {
GC_grow_table((struct hash_chain_entry ***)&GC_fo_head,
&log_fo_table_size);
GC_COND_LOG_PRINTF("Grew fo table to %u entries\n",
1 << (unsigned)log_fo_table_size);
}
/* in the THREADS case we hold allocation lock. */
base = (ptr_t)obj;
for (;;) {
index = HASH2(base, log_fo_table_size);
prev_fo = 0;
curr_fo = GC_fo_head[index];
while (curr_fo != 0) {
GC_ASSERT(GC_size(curr_fo) >= sizeof(struct finalizable_object));
if (curr_fo -> fo_hidden_base == GC_HIDE_POINTER(base)) {
/* Interruption by a signal in the middle of this */
/* should be safe. The client may see only *ocd */
/* updated, but we'll declare that to be his problem. */
if (ocd) *ocd = (void *) (curr_fo -> fo_client_data);
if (ofn) *ofn = curr_fo -> fo_fn;
/* Delete the structure for base. */
if (prev_fo == 0) {
GC_fo_head[index] = fo_next(curr_fo);
} else {
fo_set_next(prev_fo, fo_next(curr_fo));
}
if (fn == 0) {
GC_fo_entries--;
/* May not happen if we get a signal. But a high */
/* estimate will only make the table larger than */
/* necessary. */
# if !defined(THREADS) && !defined(DBG_HDRS_ALL)
GC_free((void *)curr_fo);
# endif
} else {
curr_fo -> fo_fn = fn;
curr_fo -> fo_client_data = (ptr_t)cd;
curr_fo -> fo_mark_proc = mp;
/* Reinsert it. We deleted it first to maintain */
/* consistency in the event of a signal. */
if (prev_fo == 0) {
GC_fo_head[index] = curr_fo;
} else {
fo_set_next(prev_fo, curr_fo);
}
}
UNLOCK();
# ifndef DBG_HDRS_ALL
if (EXPECT(new_fo != 0, FALSE)) {
/* Free unused new_fo returned by GC_oom_fn() */
GC_free((void *)new_fo);
}
# endif
return;
}
prev_fo = curr_fo;
curr_fo = fo_next(curr_fo);
}
if (EXPECT(new_fo != 0, FALSE)) {
/* new_fo is returned by GC_oom_fn(), so fn != 0 and hhdr != 0. */
break;
}
if (fn == 0) {
if (ocd) *ocd = 0;
if (ofn) *ofn = 0;
UNLOCK();
return;
}
GET_HDR(base, hhdr);
if (EXPECT(0 == hhdr, FALSE)) {
/* We won't collect it, hence finalizer wouldn't be run. */
if (ocd) *ocd = 0;
if (ofn) *ofn = 0;
UNLOCK();
return;
}
new_fo = (struct finalizable_object *)
GC_INTERNAL_MALLOC(sizeof(struct finalizable_object),NORMAL);
if (EXPECT(new_fo != 0, TRUE))
break;
oom_fn = GC_oom_fn;
UNLOCK();
new_fo = (struct finalizable_object *)
(*oom_fn)(sizeof(struct finalizable_object));
if (0 == new_fo) {
/* No enough memory. *ocd and *ofn remains unchanged. */
return;
}
/* It's not likely we'll make it here, but ... */
LOCK();
/* Recalculate index since the table may grow and */
/* check again that our finalizer is not in the table. */
}
GC_ASSERT(GC_size(new_fo) >= sizeof(struct finalizable_object));
if (ocd) *ocd = 0;
if (ofn) *ofn = 0;
new_fo -> fo_hidden_base = GC_HIDE_POINTER(base);
new_fo -> fo_fn = fn;
new_fo -> fo_client_data = (ptr_t)cd;
new_fo -> fo_object_size = hhdr -> hb_sz;
new_fo -> fo_mark_proc = mp;
fo_set_next(new_fo, GC_fo_head[index]);
GC_fo_entries++;
GC_fo_head[index] = new_fo;
UNLOCK();
}
GC_API void GC_CALL GC_register_finalizer(void * obj,
GC_finalization_proc fn, void * cd,
GC_finalization_proc *ofn, void ** ocd)
{
GC_register_finalizer_inner(obj, fn, cd, ofn,
ocd, GC_normal_finalize_mark_proc);
}
GC_API void GC_CALL GC_register_finalizer_ignore_self(void * obj,
GC_finalization_proc fn, void * cd,
GC_finalization_proc *ofn, void ** ocd)
{
GC_register_finalizer_inner(obj, fn, cd, ofn,
ocd, GC_ignore_self_finalize_mark_proc);
}
GC_API void GC_CALL GC_register_finalizer_no_order(void * obj,
GC_finalization_proc fn, void * cd,
GC_finalization_proc *ofn, void ** ocd)
{
GC_register_finalizer_inner(obj, fn, cd, ofn,
ocd, GC_null_finalize_mark_proc);
}
static GC_bool need_unreachable_finalization = FALSE;
/* Avoid the work if this isn't used. */
GC_API void GC_CALL GC_register_finalizer_unreachable(void * obj,
GC_finalization_proc fn, void * cd,
GC_finalization_proc *ofn, void ** ocd)
{
need_unreachable_finalization = TRUE;
GC_ASSERT(GC_java_finalization);
GC_register_finalizer_inner(obj, fn, cd, ofn,
ocd, GC_unreachable_finalize_mark_proc);
}
#ifndef NO_DEBUGGING
STATIC void GC_dump_finalization_links(
const struct dl_hashtbl_s *dl_hashtbl)
{
struct disappearing_link *curr_dl;
ptr_t real_ptr, real_link;
size_t dl_size = dl_hashtbl->log_size == -1 ? 0 :
1 << dl_hashtbl->log_size;
size_t i;
for (i = 0; i < dl_size; i++) {
for (curr_dl = dl_hashtbl -> head[i]; curr_dl != 0;
curr_dl = dl_next(curr_dl)) {
real_ptr = GC_REVEAL_POINTER(curr_dl -> dl_hidden_obj);
real_link = GC_REVEAL_POINTER(curr_dl -> dl_hidden_link);
GC_printf("Object: %p, link: %p\n", real_ptr, real_link);
}
}
}
void GC_dump_finalization(void)
{
struct finalizable_object * curr_fo;
size_t fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
ptr_t real_ptr;
size_t i;
GC_printf("Disappearing (short) links:\n");
GC_dump_finalization_links(&GC_dl_hashtbl);
# ifndef GC_LONG_REFS_NOT_NEEDED
GC_printf("Disappearing long links:\n");
GC_dump_finalization_links(&GC_ll_hashtbl);
# endif
GC_printf("Finalizers:\n");
for (i = 0; i < fo_size; i++) {
for (curr_fo = GC_fo_head[i]; curr_fo != 0;
curr_fo = fo_next(curr_fo)) {
real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
GC_printf("Finalizable object: %p\n", real_ptr);
}
}
}
#endif /* !NO_DEBUGGING */
#ifndef SMALL_CONFIG
STATIC word GC_old_dl_entries = 0; /* for stats printing */
# ifndef GC_LONG_REFS_NOT_NEEDED
STATIC word GC_old_ll_entries = 0;
# endif
#endif /* !SMALL_CONFIG */
#ifndef THREADS
/* Global variables to minimize the level of recursion when a client */
/* finalizer allocates memory. */
STATIC int GC_finalizer_nested = 0;
/* Only the lowest byte is used, the rest is */
/* padding for proper global data alignment */
/* required for some compilers (like Watcom). */
STATIC unsigned GC_finalizer_skipped = 0;
/* Checks and updates the level of finalizers recursion. */
/* Returns NULL if GC_invoke_finalizers() should not be called by the */
/* collector (to minimize the risk of a deep finalizers recursion), */
/* otherwise returns a pointer to GC_finalizer_nested. */
STATIC unsigned char *GC_check_finalizer_nested(void)
{
unsigned nesting_level = *(unsigned char *)&GC_finalizer_nested;
if (nesting_level) {
/* We are inside another GC_invoke_finalizers(). */
/* Skip some implicitly-called GC_invoke_finalizers() */
/* depending on the nesting (recursion) level. */
if (++GC_finalizer_skipped < (1U << nesting_level)) return NULL;
GC_finalizer_skipped = 0;
}
*(char *)&GC_finalizer_nested = (char)(nesting_level + 1);
return (unsigned char *)&GC_finalizer_nested;
}
#endif /* THREADS */
#define ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr_dl, prev_dl) \
{ \
size_t i; \
size_t dl_size = dl_hashtbl->log_size == -1 ? 0 : \
1 << dl_hashtbl->log_size; \
for (i = 0; i < dl_size; i++) { \
curr_dl = dl_hashtbl -> head[i]; \
prev_dl = NULL; \
while (curr_dl) {
#define ITERATE_DL_HASHTBL_END(curr_dl, prev_dl) \
prev_dl = curr_dl; \
curr_dl = dl_next(curr_dl); \
} \
} \
}
#define DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr_dl, prev_dl, next_dl) \
{ \
next_dl = dl_next(curr_dl); \
if (NULL == prev_dl) { \
dl_hashtbl -> head[i] = next_dl; \
} else { \
dl_set_next(prev_dl, next_dl); \
} \
GC_clear_mark_bit(curr_dl); \
dl_hashtbl -> entries--; \
curr_dl = next_dl; \
continue; \
}
GC_INLINE void GC_make_disappearing_links_disappear(
struct dl_hashtbl_s* dl_hashtbl)
{
struct disappearing_link *curr, *prev, *next;
ptr_t real_ptr, real_link;
ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr, prev)
real_ptr = GC_REVEAL_POINTER(curr -> dl_hidden_obj);
real_link = GC_REVEAL_POINTER(curr -> dl_hidden_link);
if (!GC_is_marked(real_ptr)) {
*(word *)real_link = 0;
GC_clear_mark_bit(curr);
DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr, prev, next);
}
ITERATE_DL_HASHTBL_END(curr, prev)
}
GC_INLINE void GC_remove_dangling_disappearing_links(
struct dl_hashtbl_s* dl_hashtbl)
{
struct disappearing_link *curr, *prev, *next;
ptr_t real_link;
ITERATE_DL_HASHTBL_BEGIN(dl_hashtbl, curr, prev)
real_link = GC_base(GC_REVEAL_POINTER(curr -> dl_hidden_link));
if (NULL != real_link && !GC_is_marked(real_link)) {
GC_clear_mark_bit(curr);
DELETE_DL_HASHTBL_ENTRY(dl_hashtbl, curr, prev, next);
}
ITERATE_DL_HASHTBL_END(curr, prev)
}
/* Called with held lock (but the world is running). */
/* Cause disappearing links to disappear and unreachable objects to be */
/* enqueued for finalization. */
GC_INNER void GC_finalize(void)
{
struct finalizable_object * curr_fo, * prev_fo, * next_fo;
ptr_t real_ptr;
size_t i;
size_t fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
# ifndef SMALL_CONFIG
/* Save current GC_[dl/ll]_entries value for stats printing */
GC_old_dl_entries = GC_dl_hashtbl.entries;
# ifndef GC_LONG_REFS_NOT_NEEDED
GC_old_ll_entries = GC_ll_hashtbl.entries;
# endif
# endif
GC_make_disappearing_links_disappear(&GC_dl_hashtbl);
/* Mark all objects reachable via chains of 1 or more pointers */
/* from finalizable objects. */
GC_ASSERT(GC_mark_state == MS_NONE);
for (i = 0; i < fo_size; i++) {
for (curr_fo = GC_fo_head[i]; curr_fo != 0;
curr_fo = fo_next(curr_fo)) {
GC_ASSERT(GC_size(curr_fo) >= sizeof(struct finalizable_object));
real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
if (!GC_is_marked(real_ptr)) {
GC_MARKED_FOR_FINALIZATION(real_ptr);
GC_MARK_FO(real_ptr, curr_fo -> fo_mark_proc);
if (GC_is_marked(real_ptr)) {
WARN("Finalization cycle involving %p\n", real_ptr);
}
}
}
}
/* Enqueue for finalization all objects that are still */
/* unreachable. */
GC_bytes_finalized = 0;
for (i = 0; i < fo_size; i++) {
curr_fo = GC_fo_head[i];
prev_fo = 0;
while (curr_fo != 0) {
real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
if (!GC_is_marked(real_ptr)) {
if (!GC_java_finalization) {
GC_set_mark_bit(real_ptr);
}
/* Delete from hash table */
next_fo = fo_next(curr_fo);
if (prev_fo == 0) {
GC_fo_head[i] = next_fo;
} else {
fo_set_next(prev_fo, next_fo);
}
GC_fo_entries--;
/* Add to list of objects awaiting finalization. */
fo_set_next(curr_fo, GC_finalize_now);
GC_finalize_now = curr_fo;
/* unhide object pointer so any future collections will */
/* see it. */
curr_fo -> fo_hidden_base =
(word)GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
GC_bytes_finalized +=
curr_fo -> fo_object_size
+ sizeof(struct finalizable_object);
GC_ASSERT(GC_is_marked(GC_base(curr_fo)));
curr_fo = next_fo;
} else {
prev_fo = curr_fo;
curr_fo = fo_next(curr_fo);
}
}
}
if (GC_java_finalization) {
/* make sure we mark everything reachable from objects finalized
using the no_order mark_proc */
for (curr_fo = GC_finalize_now;
curr_fo != NULL; curr_fo = fo_next(curr_fo)) {
real_ptr = (ptr_t)curr_fo -> fo_hidden_base;
if (!GC_is_marked(real_ptr)) {
if (curr_fo -> fo_mark_proc == GC_null_finalize_mark_proc) {
GC_MARK_FO(real_ptr, GC_normal_finalize_mark_proc);
}
if (curr_fo -> fo_mark_proc != GC_unreachable_finalize_mark_proc) {
GC_set_mark_bit(real_ptr);
}
}
}
/* now revive finalize-when-unreachable objects reachable from
other finalizable objects */
if (need_unreachable_finalization) {
curr_fo = GC_finalize_now;
prev_fo = 0;
while (curr_fo != 0) {
next_fo = fo_next(curr_fo);
if (curr_fo -> fo_mark_proc == GC_unreachable_finalize_mark_proc) {
real_ptr = (ptr_t)curr_fo -> fo_hidden_base;
if (!GC_is_marked(real_ptr)) {
GC_set_mark_bit(real_ptr);
} else {
if (prev_fo == 0)
GC_finalize_now = next_fo;
else
fo_set_next(prev_fo, next_fo);
curr_fo -> fo_hidden_base =
GC_HIDE_POINTER(curr_fo -> fo_hidden_base);
GC_bytes_finalized -=
curr_fo->fo_object_size + sizeof(struct finalizable_object);
i = HASH2(real_ptr, log_fo_table_size);
fo_set_next (curr_fo, GC_fo_head[i]);
GC_fo_entries++;
GC_fo_head[i] = curr_fo;
curr_fo = prev_fo;
}
}
prev_fo = curr_fo;
curr_fo = next_fo;
}
}
}
GC_remove_dangling_disappearing_links(&GC_dl_hashtbl);
# ifndef GC_LONG_REFS_NOT_NEEDED
GC_make_disappearing_links_disappear(&GC_ll_hashtbl);
GC_remove_dangling_disappearing_links(&GC_ll_hashtbl);
# endif
if (GC_fail_count) {
/* Don't prevent running finalizers if there has been an allocation */
/* failure recently. */
# ifdef THREADS
GC_reset_finalizer_nested();
# else
GC_finalizer_nested = 0;
# endif
}
}
#ifndef JAVA_FINALIZATION_NOT_NEEDED
/* Enqueue all remaining finalizers to be run - Assumes lock is held. */
STATIC void GC_enqueue_all_finalizers(void)
{
struct finalizable_object * curr_fo, * prev_fo, * next_fo;
ptr_t real_ptr;
register int i;
int fo_size;
fo_size = log_fo_table_size == -1 ? 0 : 1 << log_fo_table_size;
GC_bytes_finalized = 0;
for (i = 0; i < fo_size; i++) {
curr_fo = GC_fo_head[i];
prev_fo = 0;
while (curr_fo != 0) {
real_ptr = GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
GC_MARK_FO(real_ptr, GC_normal_finalize_mark_proc);
GC_set_mark_bit(real_ptr);
/* Delete from hash table */
next_fo = fo_next(curr_fo);
if (prev_fo == 0) {
GC_fo_head[i] = next_fo;
} else {
fo_set_next(prev_fo, next_fo);
}
GC_fo_entries--;
/* Add to list of objects awaiting finalization. */
fo_set_next(curr_fo, GC_finalize_now);
GC_finalize_now = curr_fo;
/* unhide object pointer so any future collections will */
/* see it. */
curr_fo -> fo_hidden_base =
(word)GC_REVEAL_POINTER(curr_fo -> fo_hidden_base);
GC_bytes_finalized +=
curr_fo -> fo_object_size + sizeof(struct finalizable_object);
curr_fo = next_fo;
}
}
}
/* Invoke all remaining finalizers that haven't yet been run.
* This is needed for strict compliance with the Java standard,
* which can make the runtime guarantee that all finalizers are run.
* Unfortunately, the Java standard implies we have to keep running
* finalizers until there are no more left, a potential infinite loop.
* YUCK.
* Note that this is even more dangerous than the usual Java
* finalizers, in that objects reachable from static variables
* may have been finalized when these finalizers are run.
* Finalizers run at this point must be prepared to deal with a
* mostly broken world.
* This routine is externally callable, so is called without
* the allocation lock.
*/
GC_API void GC_CALL GC_finalize_all(void)
{
DCL_LOCK_STATE;
LOCK();
while (GC_fo_entries > 0) {
GC_enqueue_all_finalizers();
UNLOCK();
GC_invoke_finalizers();
/* Running the finalizers in this thread is arguably not a good */
/* idea when we should be notifying another thread to run them. */
/* But otherwise we don't have a great way to wait for them to */
/* run. */
LOCK();
}
UNLOCK();
}
#endif /* !JAVA_FINALIZATION_NOT_NEEDED */
/* Returns true if it is worth calling GC_invoke_finalizers. (Useful if */
/* finalizers can only be called from some kind of "safe state" and */
/* getting into that safe state is expensive.) */
GC_API int GC_CALL GC_should_invoke_finalizers(void)
{
return GC_finalize_now != 0;
}
/* Invoke finalizers for all objects that are ready to be finalized. */
/* Should be called without allocation lock. */
GC_API int GC_CALL GC_invoke_finalizers(void)
{
struct finalizable_object * curr_fo;
int count = 0;
word bytes_freed_before = 0; /* initialized to prevent warning. */
DCL_LOCK_STATE;
while (GC_finalize_now != 0) {
# ifdef THREADS
LOCK();
# endif
if (count == 0) {
bytes_freed_before = GC_bytes_freed;
/* Don't do this outside, since we need the lock. */
}
curr_fo = GC_finalize_now;
# ifdef THREADS
if (curr_fo != 0) GC_finalize_now = fo_next(curr_fo);
UNLOCK();
if (curr_fo == 0) break;
# else
GC_finalize_now = fo_next(curr_fo);
# endif
fo_set_next(curr_fo, 0);
(*(curr_fo -> fo_fn))((ptr_t)(curr_fo -> fo_hidden_base),
curr_fo -> fo_client_data);
curr_fo -> fo_client_data = 0;
++count;
# ifdef UNDEFINED
/* This is probably a bad idea. It throws off accounting if */
/* nearly all objects are finalizable. O.w. it shouldn't */
/* matter. */
GC_free((void *)curr_fo);
# endif
}
/* bytes_freed_before is initialized whenever count != 0 */
if (count != 0 && bytes_freed_before != GC_bytes_freed) {
LOCK();
GC_finalizer_bytes_freed += (GC_bytes_freed - bytes_freed_before);
UNLOCK();
}
return count;
}
static GC_word last_finalizer_notification = 0;
GC_INNER void GC_notify_or_invoke_finalizers(void)
{
GC_finalizer_notifier_proc notifier_fn = 0;
# if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
static word last_back_trace_gc_no = 1; /* Skip first one. */
# endif
DCL_LOCK_STATE;
# if defined(THREADS) && !defined(KEEP_BACK_PTRS) \
&& !defined(MAKE_BACK_GRAPH)
/* Quick check (while unlocked) for an empty finalization queue. */
if (GC_finalize_now == 0) return;
# endif
LOCK();
/* This is a convenient place to generate backtraces if appropriate, */
/* since that code is not callable with the allocation lock. */
# if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
if (GC_gc_no > last_back_trace_gc_no) {
# ifdef KEEP_BACK_PTRS
long i;
/* Stops when GC_gc_no wraps; that's OK. */
last_back_trace_gc_no = (word)(-1); /* disable others. */
for (i = 0; i < GC_backtraces; ++i) {
/* FIXME: This tolerates concurrent heap mutation, */
/* which may cause occasional mysterious results. */
/* We need to release the GC lock, since GC_print_callers */
/* acquires it. It probably shouldn't. */
UNLOCK();
GC_generate_random_backtrace_no_gc();
LOCK();
}
last_back_trace_gc_no = GC_gc_no;
# endif
# ifdef MAKE_BACK_GRAPH
if (GC_print_back_height) {
UNLOCK();
GC_print_back_graph_stats();
LOCK();
}
# endif
}
# endif
if (GC_finalize_now == 0) {
UNLOCK();
return;
}
if (!GC_finalize_on_demand) {
unsigned char *pnested = GC_check_finalizer_nested();
UNLOCK();
/* Skip GC_invoke_finalizers() if nested */
if (pnested != NULL) {
(void) GC_invoke_finalizers();
*pnested = 0; /* Reset since no more finalizers. */
# ifndef THREADS
GC_ASSERT(GC_finalize_now == 0);
# endif /* Otherwise GC can run concurrently and add more */
}
return;
}
/* These variables require synchronization to avoid data races. */
if (last_finalizer_notification != GC_gc_no) {
last_finalizer_notification = GC_gc_no;
notifier_fn = GC_finalizer_notifier;
}
UNLOCK();
if (notifier_fn != 0)
(*notifier_fn)(); /* Invoke the notifier */
}
#ifndef SMALL_CONFIG
# ifndef GC_LONG_REFS_NOT_NEEDED
# define IF_LONG_REFS_PRESENT_ELSE(x,y) (x)
# else
# define IF_LONG_REFS_PRESENT_ELSE(x,y) (y)
# endif
GC_INNER void GC_print_finalization_stats(void)
{
struct finalizable_object *fo;
unsigned long ready = 0;
GC_log_printf("%lu finalization entries;"
" %lu/%lu short/long disappearing links alive\n",
(unsigned long)GC_fo_entries,
(unsigned long)GC_dl_hashtbl.entries,
(unsigned long)IF_LONG_REFS_PRESENT_ELSE(
GC_ll_hashtbl.entries, 0));
for (fo = GC_finalize_now; 0 != fo; fo = fo_next(fo))
++ready;
GC_log_printf("%lu finalization-ready objects;"
" %ld/%ld short/long links cleared\n",
ready,
(long)GC_old_dl_entries - (long)GC_dl_hashtbl.entries,
(long)IF_LONG_REFS_PRESENT_ELSE(
GC_old_ll_entries - GC_ll_hashtbl.entries, 0));
}
#endif /* !SMALL_CONFIG */
#endif /* !GC_NO_FINALIZATION */