/* arbitrary remove only works with double linked heap, and is only required by
* reference counting so far.
*/
DUK_INTERNAL void duk_heap_remove_any_from_heap_allocated(duk_heap *heap, duk_heaphdr *hdr) {
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(hdr) != DUK_HTYPE_STRING);
if (DUK_HEAPHDR_GET_PREV(heap, hdr)) {
DUK_HEAPHDR_SET_NEXT(heap, DUK_HEAPHDR_GET_PREV(heap, hdr), DUK_HEAPHDR_GET_NEXT(heap, hdr));
} else {
heap->heap_allocated = DUK_HEAPHDR_GET_NEXT(heap, hdr);
}
if (DUK_HEAPHDR_GET_NEXT(heap, hdr)) {
DUK_HEAPHDR_SET_PREV(heap, DUK_HEAPHDR_GET_NEXT(heap, hdr), DUK_HEAPHDR_GET_PREV(heap, hdr));
} else {
;
}
}
DUK_INTERNAL void duk_heap_insert_into_heap_allocated(duk_heap *heap, duk_heaphdr *hdr) {
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(hdr) != DUK_HTYPE_STRING);
#ifdef DUK_USE_DOUBLE_LINKED_HEAP
if (heap->heap_allocated) {
DUK_ASSERT(DUK_HEAPHDR_GET_PREV(heap, heap->heap_allocated) == NULL);
DUK_HEAPHDR_SET_PREV(heap, heap->heap_allocated, hdr);
}
DUK_HEAPHDR_SET_PREV(heap, hdr, NULL);
#endif
DUK_HEAPHDR_SET_NEXT(heap, hdr, heap->heap_allocated);
heap->heap_allocated = hdr;
}
DUK_LOCAL void duk__print_shared_heaphdr(duk__dprint_state *st, duk_heaphdr *h) {
duk_fixedbuffer *fb = st->fb;
if (st->heavy) {
duk_fb_sprintf(fb, "(%p)", (void *) h);
}
if (!h) {
return;
}
if (st->binary) {
duk_size_t i;
duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_LBRACKET);
for (i = 0; i < (duk_size_t) sizeof(*h); i++) {
duk_fb_sprintf(fb, "%02lx", (unsigned long) ((duk_uint8_t *)h)[i]);
}
duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_RBRACKET);
}
#if defined(DUK_USE_REFERENCE_COUNTING) /* currently implicitly also DUK_USE_DOUBLE_LINKED_HEAP */
if (st->heavy) {
duk_fb_sprintf(fb, "[h_next=%p,h_prev=%p,h_refcount=%lu,h_flags=%08lx,type=%ld,"
"reachable=%ld,temproot=%ld,finalizable=%ld,finalized=%ld]",
(void *) DUK_HEAPHDR_GET_NEXT(NULL, h),
(void *) DUK_HEAPHDR_GET_PREV(NULL, h),
(unsigned long) DUK_HEAPHDR_GET_REFCOUNT(h),
(unsigned long) DUK_HEAPHDR_GET_FLAGS(h),
(long) DUK_HEAPHDR_GET_TYPE(h),
(long) (DUK_HEAPHDR_HAS_REACHABLE(h) ? 1 : 0),
(long) (DUK_HEAPHDR_HAS_TEMPROOT(h) ? 1 : 0),
(long) (DUK_HEAPHDR_HAS_FINALIZABLE(h) ? 1 : 0),
(long) (DUK_HEAPHDR_HAS_FINALIZED(h) ? 1 : 0));
}
#else
if (st->heavy) {
duk_fb_sprintf(fb, "[h_next=%p,h_flags=%08lx,type=%ld,reachable=%ld,temproot=%ld,finalizable=%ld,finalized=%ld]",
(void *) DUK_HEAPHDR_GET_NEXT(NULL, h),
(unsigned long) DUK_HEAPHDR_GET_FLAGS(h),
(long) DUK_HEAPHDR_GET_TYPE(h),
(long) (DUK_HEAPHDR_HAS_REACHABLE(h) ? 1 : 0),
(long) (DUK_HEAPHDR_HAS_TEMPROOT(h) ? 1 : 0),
(long) (DUK_HEAPHDR_HAS_FINALIZABLE(h) ? 1 : 0),
(long) (DUK_HEAPHDR_HAS_FINALIZED(h) ? 1 : 0));
}
#endif
}
static void duk__refzero_free_pending(duk_hthread *thr) {
duk_heaphdr *h1, *h2;
duk_heap *heap;
duk_int_t count = 0;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(thr->heap != NULL);
heap = thr->heap;
DUK_ASSERT(heap != NULL);
/*
* Detect recursive invocation
*/
if (DUK_HEAP_HAS_REFZERO_FREE_RUNNING(heap)) {
DUK_DDD(DUK_DDDPRINT("refzero free running, skip run"));
return;
}
/*
* Churn refzero_list until empty
*/
DUK_HEAP_SET_REFZERO_FREE_RUNNING(heap);
while (heap->refzero_list) {
duk_hobject *obj;
duk_bool_t rescued = 0;
/*
* Pick an object from the head (don't remove yet).
*/
h1 = heap->refzero_list;
obj = (duk_hobject *) h1;
DUK_DD(DUK_DDPRINT("refzero processing %p: %!O", (void *) h1, (duk_heaphdr *) h1));
DUK_ASSERT(DUK_HEAPHDR_GET_PREV(h1) == NULL);
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(h1) == DUK_HTYPE_OBJECT); /* currently, always the case */
/*
* Finalizer check.
*
* Note: running a finalizer may have arbitrary side effects, e.g.
* queue more objects on refzero_list (tail), or even trigger a
* mark-and-sweep.
*
* Note: quick reject check should match vast majority of
* objects and must be safe (not throw any errors, ever).
*/
/* XXX: If object has FINALIZED, it was finalized by mark-and-sweep on
* its previous run. Any point in running finalizer again here? If
* finalization semantics is changed so that finalizer is only run once,
* checking for FINALIZED would happen here.
*/
/* A finalizer is looked up from the object and up its prototype chain
* (which allows inherited finalizers).
*/
if (duk_hobject_hasprop_raw(thr, obj, DUK_HTHREAD_STRING_INT_FINALIZER(thr))) {
DUK_DDD(DUK_DDDPRINT("object has a finalizer, run it"));
DUK_ASSERT(h1->h_refcount == 0);
h1->h_refcount++; /* bump refcount to prevent refzero during finalizer processing */
duk_hobject_run_finalizer(thr, obj); /* must never longjmp */
h1->h_refcount--; /* remove artificial bump */
DUK_ASSERT_DISABLE(h1->h_refcount >= 0); /* refcount is unsigned, so always true */
if (h1->h_refcount != 0) {
DUK_DDD(DUK_DDDPRINT("-> object refcount after finalization non-zero, object will be rescued"));
rescued = 1;
} else {
DUK_DDD(DUK_DDDPRINT("-> object refcount still zero after finalization, object will be freed"));
}
}
/* Refzero head is still the same. This is the case even if finalizer
* inserted more refzero objects; they are inserted to the tail.
*/
DUK_ASSERT(h1 == heap->refzero_list);
/*
* Remove the object from the refzero list. This cannot be done
* before a possible finalizer has been executed; the finalizer
* may trigger a mark-and-sweep, and mark-and-sweep must be able
* to traverse a complete refzero_list.
*/
h2 = DUK_HEAPHDR_GET_NEXT(h1);
if (h2) {
DUK_HEAPHDR_SET_PREV(h2, NULL); /* not strictly necessary */
heap->refzero_list = h2;
} else {
heap->refzero_list = NULL;
heap->refzero_list_tail = NULL;
}
/*
* Rescue or free.
*/
if (rescued) {
/* yes -> move back to heap allocated */
DUK_DD(DUK_DDPRINT("object rescued during refcount finalization: %p", (void *) h1));
DUK_HEAPHDR_SET_PREV(h1, NULL);
DUK_HEAPHDR_SET_NEXT(h1, heap->heap_allocated);
heap->heap_allocated = h1;
} else {
/* no -> decref members, then free */
duk__refcount_finalize_hobject(thr, obj);
duk_heap_free_heaphdr_raw(heap, h1);
}
count++;
}
DUK_HEAP_CLEAR_REFZERO_FREE_RUNNING(heap);
DUK_DDD(DUK_DDDPRINT("refzero processed %ld objects", (long) count));
/*
* Once the whole refzero cascade has been freed, check for
* a voluntary mark-and-sweep.
*/
#if defined(DUK_USE_MARK_AND_SWEEP) && defined(DUK_USE_VOLUNTARY_GC)
/* 'count' is more or less comparable to normal trigger counter update
* which happens in memory block (re)allocation.
*/
heap->mark_and_sweep_trigger_counter -= count;
if (heap->mark_and_sweep_trigger_counter <= 0) {
duk_bool_t rc;
duk_small_uint_t flags = 0; /* not emergency */
DUK_D(DUK_DPRINT("refcount triggering mark-and-sweep"));
rc = duk_heap_mark_and_sweep(heap, flags);
DUK_UNREF(rc);
DUK_D(DUK_DPRINT("refcount triggered mark-and-sweep => rc %ld", (long) rc));
}
#endif /* DUK_USE_MARK_AND_SWEEP && DUK_USE_VOLUNTARY_GC */
}
