DUK_LOCAL void duk__assert_heaphdr_flags(duk_heap *heap) {
duk_heaphdr *hdr;
hdr = heap->heap_allocated;
while (hdr) {
DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(hdr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_TEMPROOT(hdr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(hdr));
/* may have FINALIZED */
hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
}
#if defined(DUK_USE_REFERENCE_COUNTING)
hdr = heap->refzero_list;
while (hdr) {
DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(hdr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_TEMPROOT(hdr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(hdr));
/* DUK_HEAPHDR_HAS_FINALIZED may be set if we're doing a
* refzero finalization and mark-and-sweep gets triggered
* during the finalizer.
*/
/* DUK_HEAPHDR_HAS_FINALIZED may or may not be set. */
hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
}
#endif /* DUK_USE_REFERENCE_COUNTING */
}
DUK_LOCAL void duk__finalize_refcounts(duk_heap *heap) {
duk_hthread *thr;
duk_heaphdr *hdr;
thr = duk__get_temp_hthread(heap);
DUK_ASSERT(thr != NULL);
DUK_DD(DUK_DDPRINT("duk__finalize_refcounts: heap=%p, hthread=%p",
(void *) heap, (void *) thr));
hdr = heap->heap_allocated;
while (hdr) {
if (!DUK_HEAPHDR_HAS_REACHABLE(hdr)) {
/*
* Unreachable object about to be swept. Finalize target refcounts
* (objects which the unreachable object points to) without doing
* refzero processing. Recursive decrefs are also prevented when
* refzero processing is disabled.
*
* Value cannot be a finalizable object, as they have been made
* temporarily reachable for this round.
*/
DUK_DDD(DUK_DDDPRINT("unreachable object, refcount finalize before sweeping: %p", (void *) hdr));
duk_heaphdr_refcount_finalize(thr, hdr);
}
hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
}
}
/* free inner references (these exist e.g. when external
* strings are enabled)
*/
duk_free_hstring_inner(heap, h);
DUK_FREE(heap, h);
(*count_free)++;
}
}
#else /* DUK_USE_HEAPPTR16 */
DUK_LOCAL void duk__sweep_string_chain(duk_heap *heap, duk_hstring **slot, duk_size_t *count_keep, duk_size_t *count_free) {
duk_hstring *h = *slot;
if (h == NULL) {
/* nop */
return;
}
if (DUK_HEAPHDR_HAS_REACHABLE((duk_heaphdr *) h)) {
DUK_HEAPHDR_CLEAR_REACHABLE((duk_heaphdr *) h);
(*count_keep)++;
} else {
#if defined(DUK_USE_REFERENCE_COUNTING)
DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h) == 0);
#endif
/* deal with weak references first */
duk_heap_strcache_string_remove(heap, (duk_hstring *) h);
*slot = NULL;
/* free inner references (these exist e.g. when external
* strings are enabled)
*/
duk_free_hstring_inner(heap, h);
DUK_FREE(heap, h);
(*count_free)++;
}
}
DUK_LOCAL void duk__mark_finalizable(duk_heap *heap) {
duk_hthread *thr;
duk_heaphdr *hdr;
duk_size_t count_finalizable = 0;
DUK_DD(DUK_DDPRINT("duk__mark_finalizable: %p", (void *) heap));
thr = duk__get_temp_hthread(heap);
DUK_ASSERT(thr != NULL);
hdr = heap->heap_allocated;
while (hdr) {
/* A finalizer is looked up from the object and up its prototype chain
* (which allows inherited finalizers). A prototype loop must not cause
* an error to be thrown here; duk_hobject_hasprop_raw() will ignore a
* prototype loop silently and indicate that the property doesn't exist.
*/
if (!DUK_HEAPHDR_HAS_REACHABLE(hdr) &&
DUK_HEAPHDR_GET_TYPE(hdr) == DUK_HTYPE_OBJECT &&
!DUK_HEAPHDR_HAS_FINALIZED(hdr) &&
duk_hobject_hasprop_raw(thr, (duk_hobject *) hdr, DUK_HTHREAD_STRING_INT_FINALIZER(thr))) {
/* heaphdr:
* - is not reachable
* - is an object
* - is not a finalized object
* - has a finalizer
*/
DUK_DD(DUK_DDPRINT("unreachable heap object will be "
"finalized -> mark as finalizable "
"and treat as a reachability root: %p",
(void *) hdr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY(hdr));
DUK_HEAPHDR_SET_FINALIZABLE(hdr);
count_finalizable ++;
}
hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
}
if (count_finalizable == 0) {
return;
}
DUK_DD(DUK_DDPRINT("marked %ld heap objects as finalizable, now mark them reachable",
(long) count_finalizable));
hdr = heap->heap_allocated;
while (hdr) {
if (DUK_HEAPHDR_HAS_FINALIZABLE(hdr)) {
duk__mark_heaphdr(heap, hdr);
}
hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
}
/* Caller will finish the marking process if we hit a recursion limit. */
}
DUK_LOCAL void duk__sweep_string_chain16(duk_heap *heap, duk_uint16_t *slot, duk_size_t *count_keep, duk_size_t *count_free) {
duk_uint16_t h16 = *slot;
duk_hstring *h;
duk_uint16_t null16 = heap->heapptr_null16;
if (h16 == null16) {
/* nop */
return;
}
h = (duk_hstring *) DUK_USE_HEAPPTR_DEC16(heap->heap_udata, h16);
DUK_ASSERT(h != NULL);
if (DUK_HEAPHDR_HAS_REACHABLE((duk_heaphdr *) h)) {
DUK_HEAPHDR_CLEAR_REACHABLE((duk_heaphdr *) h);
(*count_keep)++;
} else {
#if defined(DUK_USE_REFERENCE_COUNTING)
DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h) == 0);
#endif
/* deal with weak references first */
duk_heap_strcache_string_remove(heap, (duk_hstring *) h);
*slot = null16;
/* free inner references (these exist e.g. when external
* strings are enabled)
*/
duk_free_hstring_inner(heap, h);
DUK_FREE(heap, h);
(*count_free)++;
}
}
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
}
DUK_LOCAL void duk__run_object_finalizers(duk_heap *heap, duk_small_uint_t flags) {
duk_heaphdr *curr;
duk_heaphdr *next;
#if defined(DUK_USE_DEBUG)
duk_size_t count = 0;
#endif
duk_hthread *thr;
DUK_DD(DUK_DDPRINT("duk__run_object_finalizers: %p", (void *) heap));
thr = duk__get_temp_hthread(heap);
DUK_ASSERT(thr != NULL);
curr = heap->finalize_list;
while (curr) {
DUK_DDD(DUK_DDDPRINT("mark-and-sweep finalize: %p", (void *) curr));
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT); /* only objects have finalizers */
DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(curr)); /* flags have been already cleared */
DUK_ASSERT(!DUK_HEAPHDR_HAS_TEMPROOT(curr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(curr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY(curr)); /* No finalizers for ROM objects */
if (DUK_LIKELY((flags & DUK_MS_FLAG_SKIP_FINALIZERS) == 0)) {
/* Run the finalizer, duk_hobject_run_finalizer() sets FINALIZED.
* Next mark-and-sweep will collect the object unless it has
* become reachable (i.e. rescued). FINALIZED prevents the
* finalizer from being executed again before that.
*/
duk_hobject_run_finalizer(thr, (duk_hobject *) curr); /* must never longjmp */
DUK_ASSERT(DUK_HEAPHDR_HAS_FINALIZED(curr));
} else {
/* Used during heap destruction: don't actually run finalizers
* because we're heading into forced finalization. Instead,
* queue finalizable objects back to the heap_allocated list.
*/
DUK_D(DUK_DPRINT("skip finalizers flag set, queue object to heap_allocated without finalizing"));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
}
/* queue back to heap_allocated */
next = DUK_HEAPHDR_GET_NEXT(heap, curr);
DUK_HEAP_INSERT_INTO_HEAP_ALLOCATED(heap, curr);
curr = next;
#if defined(DUK_USE_DEBUG)
count++;
#endif
}
/* finalize_list will always be processed completely */
heap->finalize_list = NULL;
#if defined(DUK_USE_DEBUG)
DUK_D(DUK_DPRINT("mark-and-sweep finalize objects: %ld finalizers called", (long) count));
#endif
}
static void duk__sweep_stringtable(duk_heap *heap, duk_size_t *out_count_keep) {
duk_hstring *h;
duk_uint_fast32_t i;
#ifdef DUK_USE_DEBUG
duk_size_t count_free = 0;
#endif
duk_size_t count_keep = 0;
DUK_DD(DUK_DDPRINT("duk__sweep_stringtable: %p", (void *) heap));
for (i = 0; i < heap->st_size; i++) {
h = heap->st[i];
if (h == NULL || h == DUK_STRTAB_DELETED_MARKER(heap)) {
continue;
} else if (DUK_HEAPHDR_HAS_REACHABLE((duk_heaphdr *) h)) {
DUK_HEAPHDR_CLEAR_REACHABLE((duk_heaphdr *) h);
count_keep++;
continue;
}
#ifdef DUK_USE_DEBUG
count_free++;
#endif
#if defined(DUK_USE_REFERENCE_COUNTING)
/* Non-zero refcounts should not happen for unreachable strings,
* because we refcount finalize all unreachable objects which
* should have decreased unreachable string refcounts to zero
* (even for cycles).
*/
DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h) == 0);
#endif
DUK_DDD(DUK_DDDPRINT("sweep string, not reachable: %p", (void *) h));
/* deal with weak references first */
duk_heap_strcache_string_remove(heap, (duk_hstring *) h);
/* remove the string (mark DELETED), could also call
* duk_heap_string_remove() but that would be slow and
* pointless because we already know the slot.
*/
heap->st[i] = DUK_STRTAB_DELETED_MARKER(heap);
/* then free */
#if 1
DUK_FREE(heap, (duk_heaphdr *) h); /* no inner refs/allocs, just free directly */
#else
duk_heap_free_heaphdr_raw(heap, (duk_heaphdr *) h); /* this would be OK but unnecessary */
#endif
}
#ifdef DUK_USE_DEBUG
DUK_D(DUK_DPRINT("mark-and-sweep sweep stringtable: %d freed, %d kept",
(int) count_free, (int) count_keep));
#endif
*out_count_keep = count_keep;
}
static void duk__mark_finalizable(duk_heap *heap) {
duk_hthread *thr;
duk_heaphdr *hdr;
int count_finalizable = 0;
DUK_DD(DUK_DDPRINT("duk__mark_finalizable: %p", (void *) heap));
thr = duk__get_temp_hthread(heap);
DUK_ASSERT(thr != NULL);
hdr = heap->heap_allocated;
while (hdr) {
/* A finalizer is looked up from the object and up its prototype chain
* (which allows inherited finalizers).
*/
if (!DUK_HEAPHDR_HAS_REACHABLE(hdr) &&
DUK_HEAPHDR_GET_TYPE(hdr) == DUK_HTYPE_OBJECT &&
!DUK_HEAPHDR_HAS_FINALIZED(hdr) &&
duk_hobject_hasprop_raw(thr, (duk_hobject *) hdr, DUK_HTHREAD_STRING_INT_FINALIZER(thr))) {
/* heaphdr:
* - is not reachable
* - is an object
* - is not a finalized object
* - has a finalizer
*/
DUK_DD(DUK_DDPRINT("unreachable heap object will be finalized -> mark as finalizable and treat as a reachability root: %p", hdr));
DUK_HEAPHDR_SET_FINALIZABLE(hdr);
count_finalizable ++;
}
hdr = DUK_HEAPHDR_GET_NEXT(hdr);
}
if (count_finalizable == 0) {
return;
}
DUK_DD(DUK_DDPRINT("marked %d heap objects as finalizable, now mark them reachable", count_finalizable));
hdr = heap->heap_allocated;
while (hdr) {
if (DUK_HEAPHDR_HAS_FINALIZABLE(hdr)) {
duk__mark_heaphdr(heap, hdr);
}
hdr = DUK_HEAPHDR_GET_NEXT(hdr);
}
/* Caller will finish the marking process if we hit a recursion limit. */
}
static void duk__assert_heaphdr_flags(duk_heap *heap) {
duk_heaphdr *hdr;
hdr = heap->heap_allocated;
while (hdr) {
DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(hdr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_TEMPROOT(hdr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(hdr));
/* may have FINALIZED */
hdr = DUK_HEAPHDR_GET_NEXT(hdr);
}
#ifdef DUK_USE_REFERENCE_COUNTING
hdr = heap->refzero_list;
while (hdr) {
DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(hdr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_TEMPROOT(hdr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(hdr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(hdr));
hdr = DUK_HEAPHDR_GET_NEXT(hdr);
}
#endif /* DUK_USE_REFERENCE_COUNTING */
}
static void duk__run_object_finalizers(duk_heap *heap) {
duk_heaphdr *curr;
duk_heaphdr *next;
#ifdef DUK_USE_DEBUG
int count = 0;
#endif
duk_hthread *thr;
DUK_DD(DUK_DDPRINT("duk__run_object_finalizers: %p", (void *) heap));
thr = duk__get_temp_hthread(heap);
DUK_ASSERT(thr != NULL);
curr = heap->finalize_list;
while (curr) {
DUK_DDD(DUK_DDDPRINT("mark-and-sweep finalize: %p", (void *) curr));
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT); /* only objects have finalizers */
DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(curr)); /* flags have been already cleared */
DUK_ASSERT(!DUK_HEAPHDR_HAS_TEMPROOT(curr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(curr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
/* run the finalizer */
duk_hobject_run_finalizer(thr, (duk_hobject *) curr); /* must never longjmp */
/* mark FINALIZED, for next mark-and-sweep (will collect unless has become reachable;
* prevent running finalizer again if reachable)
*/
DUK_HEAPHDR_SET_FINALIZED(curr);
/* queue back to heap_allocated */
next = DUK_HEAPHDR_GET_NEXT(curr);
DUK_HEAP_INSERT_INTO_HEAP_ALLOCATED(heap, curr);
curr = next;
#ifdef DUK_USE_DEBUG
count++;
#endif
}
/* finalize_list will always be processed completely */
heap->finalize_list = NULL;
#ifdef DUK_USE_DEBUG
DUK_D(DUK_DPRINT("mark-and-sweep finalize objects: %d finalizers called", count));
#endif
}
/* recursion tracking happens here only */
DUK_LOCAL void duk__mark_heaphdr(duk_heap *heap, duk_heaphdr *h) {
DUK_DDD(DUK_DDDPRINT("duk__mark_heaphdr %p, type %ld",
(void *) h,
(h != NULL ? (long) DUK_HEAPHDR_GET_TYPE(h) : (long) -1)));
if (!h) {
return;
}
#if defined(DUK_USE_ROM_OBJECTS)
if (DUK_HEAPHDR_HAS_READONLY(h)) {
DUK_DDD(DUK_DDDPRINT("readonly object %p, skip", (void *) h));
return;
}
#endif
if (DUK_HEAPHDR_HAS_REACHABLE(h)) {
DUK_DDD(DUK_DDDPRINT("already marked reachable, skip"));
return;
}
DUK_HEAPHDR_SET_REACHABLE(h);
if (heap->mark_and_sweep_recursion_depth >= DUK_USE_MARK_AND_SWEEP_RECLIMIT) {
/* log this with a normal debug level because this should be relatively rare */
DUK_D(DUK_DPRINT("mark-and-sweep recursion limit reached, marking as temproot: %p", (void *) h));
DUK_HEAP_SET_MARKANDSWEEP_RECLIMIT_REACHED(heap);
DUK_HEAPHDR_SET_TEMPROOT(h);
return;
}
heap->mark_and_sweep_recursion_depth++;
switch (DUK_HEAPHDR_GET_TYPE(h)) {
case DUK_HTYPE_STRING:
duk__mark_hstring(heap, (duk_hstring *) h);
break;
case DUK_HTYPE_OBJECT:
duk__mark_hobject(heap, (duk_hobject *) h);
break;
case DUK_HTYPE_BUFFER:
/* nothing to mark */
break;
default:
DUK_D(DUK_DPRINT("attempt to mark heaphdr %p with invalid htype %ld", (void *) h, (long) DUK_HEAPHDR_GET_TYPE(h)));
DUK_UNREACHABLE();
}
heap->mark_and_sweep_recursion_depth--;
}
DUK_LOCAL void duk__sweep_stringtable(duk_heap *heap, duk_size_t *out_count_keep) {
duk_hstring *h;
duk_hstring *prev;
duk_uint32_t i;
#if defined(DUK_USE_DEBUG)
duk_size_t count_free = 0;
#endif
duk_size_t count_keep = 0;
DUK_DD(DUK_DDPRINT("duk__sweep_stringtable: %p", (void *) heap));
#if defined(DUK_USE_STRTAB_PTRCOMP)
if (heap->strtable16 == NULL) {
#else
if (heap->strtable == NULL) {
#endif
goto done;
}
for (i = 0; i < heap->st_size; i++) {
#if defined(DUK_USE_STRTAB_PTRCOMP)
h = DUK_USE_HEAPPTR_DEC16(heap->heap_udata, heap->strtable16[i]);
#else
h = heap->strtable[i];
#endif
prev = NULL;
while (h != NULL) {
duk_hstring *next;
next = h->hdr.h_next;
if (DUK_HEAPHDR_HAS_REACHABLE((duk_heaphdr *) h)) {
DUK_HEAPHDR_CLEAR_REACHABLE((duk_heaphdr *) h);
count_keep++;
prev = h;
} else {
#if defined(DUK_USE_DEBUG)
count_free++;
#endif
#if defined(DUK_USE_REFERENCE_COUNTING)
/* Non-zero refcounts should not happen for unreachable strings,
* because we refcount finalize all unreachable objects which
* should have decreased unreachable string refcounts to zero
* (even for cycles).
*/
DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h) == 0);
#endif
/* deal with weak references first */
duk_heap_strcache_string_remove(heap, (duk_hstring *) h);
/* remove the string from the string table */
duk_heap_strtable_unlink_prev(heap, (duk_hstring *) h, (duk_hstring *) prev);
/* free inner references (these exist e.g. when external
* strings are enabled) and the struct itself.
*/
duk_free_hstring(heap, (duk_hstring *) h);
/* don't update 'prev'; it should be last string kept */
}
h = next;
}
}
done:
#if defined(DUK_USE_DEBUG)
DUK_D(DUK_DPRINT("mark-and-sweep sweep stringtable: %ld freed, %ld kept",
(long) count_free, (long) count_keep));
#endif
*out_count_keep = count_keep;
}
/*
* Sweep heap
*/
DUK_LOCAL void duk__sweep_heap(duk_heap *heap, duk_int_t flags, duk_size_t *out_count_keep) {
duk_heaphdr *prev; /* last element that was left in the heap */
duk_heaphdr *curr;
duk_heaphdr *next;
#if defined(DUK_USE_DEBUG)
duk_size_t count_free = 0;
duk_size_t count_finalize = 0;
duk_size_t count_rescue = 0;
#endif
duk_size_t count_keep = 0;
DUK_UNREF(flags);
DUK_DD(DUK_DDPRINT("duk__sweep_heap: %p", (void *) heap));
prev = NULL;
curr = heap->heap_allocated;
heap->heap_allocated = NULL;
while (curr) {
/* Strings and ROM objects are never placed on the heap allocated list. */
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) != DUK_HTYPE_STRING);
DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY(curr));
next = DUK_HEAPHDR_GET_NEXT(heap, curr);
if (DUK_HEAPHDR_HAS_REACHABLE(curr)) {
/*
* Reachable object, keep
*/
DUK_DDD(DUK_DDDPRINT("sweep, reachable: %p", (void *) curr));
if (DUK_HEAPHDR_HAS_FINALIZABLE(curr)) {
/*
* If object has been marked finalizable, move it to the
* "to be finalized" work list. It will be collected on
* the next mark-and-sweep if it is still unreachable
* after running the finalizer.
*/
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT);
DUK_DDD(DUK_DDDPRINT("object has finalizer, move to finalization work list: %p", (void *) curr));
#if defined(DUK_USE_DOUBLE_LINKED_HEAP)
if (heap->finalize_list) {
DUK_HEAPHDR_SET_PREV(heap, heap->finalize_list, curr);
}
DUK_HEAPHDR_SET_PREV(heap, curr, NULL);
#endif
DUK_HEAPHDR_SET_NEXT(heap, curr, heap->finalize_list);
DUK_ASSERT_HEAPHDR_LINKS(heap, curr);
heap->finalize_list = curr;
#if defined(DUK_USE_DEBUG)
count_finalize++;
#endif
} else {
/*
* Object will be kept; queue object back to heap_allocated (to tail)
*/
if (DUK_HEAPHDR_HAS_FINALIZED(curr)) {
/*
* Object's finalizer was executed on last round, and
* object has been happily rescued.
*/
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(curr));
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT);
DUK_DD(DUK_DDPRINT("object rescued during mark-and-sweep finalization: %p", (void *) curr));
#if defined(DUK_USE_DEBUG)
count_rescue++;
#endif
} else {
/*
* Plain, boring reachable object.
*/
DUK_DD(DUK_DDPRINT("keep object: %!iO", curr));
count_keep++;
}
if (!heap->heap_allocated) {
heap->heap_allocated = curr;
}
if (prev) {
DUK_HEAPHDR_SET_NEXT(heap, prev, curr);
}
#if defined(DUK_USE_DOUBLE_LINKED_HEAP)
DUK_HEAPHDR_SET_PREV(heap, curr, prev);
#endif
DUK_ASSERT_HEAPHDR_LINKS(heap, prev);
DUK_ASSERT_HEAPHDR_LINKS(heap, curr);
prev = curr;
}
DUK_HEAPHDR_CLEAR_REACHABLE(curr);
DUK_HEAPHDR_CLEAR_FINALIZED(curr);
DUK_HEAPHDR_CLEAR_FINALIZABLE(curr);
DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(curr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(curr));
curr = next;
} else {
/*
* Unreachable object, free
*/
DUK_DDD(DUK_DDDPRINT("sweep, not reachable: %p", (void *) curr));
#if defined(DUK_USE_REFERENCE_COUNTING)
/* Non-zero refcounts should not happen because we refcount
* finalize all unreachable objects which should cancel out
* refcounts (even for cycles).
*/
DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(curr) == 0);
#endif
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(curr));
if (DUK_HEAPHDR_HAS_FINALIZED(curr)) {
DUK_DDD(DUK_DDDPRINT("finalized object not rescued: %p", (void *) curr));
}
/* Note: object cannot be a finalizable unreachable object, as
* they have been marked temporarily reachable for this round,
* and are handled above.
*/
#if defined(DUK_USE_DEBUG)
count_free++;
#endif
/* weak refs should be handled here, but no weak refs for
* any non-string objects exist right now.
*/
/* free object and all auxiliary (non-heap) allocs */
duk_heap_free_heaphdr_raw(heap, curr);
curr = next;
}
}
if (prev) {
DUK_HEAPHDR_SET_NEXT(heap, prev, NULL);
}
DUK_ASSERT_HEAPHDR_LINKS(heap, prev);
#if defined(DUK_USE_DEBUG)
DUK_D(DUK_DPRINT("mark-and-sweep sweep objects (non-string): %ld freed, %ld kept, %ld rescued, %ld queued for finalization",
(long) count_free, (long) count_keep, (long) count_rescue, (long) count_finalize));
#endif
*out_count_keep = count_keep;
}
static void duk__sweep_heap(duk_heap *heap, duk_int_t flags, duk_size_t *out_count_keep) {
duk_heaphdr *prev; /* last element that was left in the heap */
duk_heaphdr *curr;
duk_heaphdr *next;
#ifdef DUK_USE_DEBUG
duk_size_t count_free = 0;
duk_size_t count_finalize = 0;
duk_size_t count_rescue = 0;
#endif
duk_size_t count_keep = 0;
DUK_UNREF(flags);
DUK_DD(DUK_DDPRINT("duk__sweep_heap: %p", (void *) heap));
prev = NULL;
curr = heap->heap_allocated;
heap->heap_allocated = NULL;
while (curr) {
/* strings are never placed on the heap allocated list */
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) != DUK_HTYPE_STRING);
next = DUK_HEAPHDR_GET_NEXT(curr);
if (DUK_HEAPHDR_HAS_REACHABLE(curr)) {
/*
* Reachable object, keep
*/
DUK_DDD(DUK_DDDPRINT("sweep, reachable: %p", (void *) curr));
if (DUK_HEAPHDR_HAS_FINALIZABLE(curr)) {
/*
* If object has been marked finalizable, move it to the
* "to be finalized" work list. It will be collected on
* the next mark-and-sweep if it is still unreachable
* after running the finalizer.
*/
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT);
DUK_DDD(DUK_DDDPRINT("object has finalizer, move to finalization work list: %p", (void *) curr));
#ifdef DUK_USE_DOUBLE_LINKED_HEAP
if (heap->finalize_list) {
DUK_HEAPHDR_SET_PREV(heap->finalize_list, curr);
}
DUK_HEAPHDR_SET_PREV(curr, NULL);
#endif
DUK_HEAPHDR_SET_NEXT(curr, heap->finalize_list);
heap->finalize_list = curr;
#ifdef DUK_USE_DEBUG
count_finalize++;
#endif
} else {
/*
* Object will be kept; queue object back to heap_allocated (to tail)
*/
if (DUK_HEAPHDR_HAS_FINALIZED(curr)) {
/*
* Object's finalizer was executed on last round, and
* object has been happily rescued.
*/
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(curr));
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT);
DUK_DD(DUK_DDPRINT("object rescued during mark-and-sweep finalization: %p", (void *) curr));
#ifdef DUK_USE_DEBUG
count_rescue++;
#endif
} else {
/*
* Plain, boring reachable object.
*/
count_keep++;
}
if (!heap->heap_allocated) {
heap->heap_allocated = curr;
}
if (prev) {
DUK_HEAPHDR_SET_NEXT(prev, curr);
}
#ifdef DUK_USE_DOUBLE_LINKED_HEAP
DUK_HEAPHDR_SET_PREV(curr, prev);
#endif
prev = curr;
}
DUK_HEAPHDR_CLEAR_REACHABLE(curr);
DUK_HEAPHDR_CLEAR_FINALIZED(curr);
DUK_HEAPHDR_CLEAR_FINALIZABLE(curr);
DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(curr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(curr));
curr = next;
} else {
/*
* Unreachable object, free
*/
DUK_DDD(DUK_DDDPRINT("sweep, not reachable: %p", (void *) curr));
#if defined(DUK_USE_REFERENCE_COUNTING)
/* Non-zero refcounts should not happen because we refcount
* finalize all unreachable objects which should cancel out
* refcounts (even for cycles).
*/
DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(curr) == 0);
#endif
DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(curr));
if (DUK_HEAPHDR_HAS_FINALIZED(curr)) {
DUK_DDD(DUK_DDDPRINT("finalized object not rescued: %p", (void *) curr));
}
/* Note: object cannot be a finalizable unreachable object, as
* they have been marked temporarily reachable for this round,
* and are handled above.
*/
#ifdef DUK_USE_DEBUG
count_free++;
#endif
/* weak refs should be handled here, but no weak refs for
* any non-string objects exist right now.
*/
/* free object and all auxiliary (non-heap) allocs */
duk_heap_free_heaphdr_raw(heap, curr);
curr = next;
}
}
if (prev) {
DUK_HEAPHDR_SET_NEXT(prev, NULL);
}
#ifdef DUK_USE_DEBUG
DUK_D(DUK_DPRINT("mark-and-sweep sweep objects (non-string): %d freed, %d kept, %d rescued, %d queued for finalization",
(int) count_free, (int) count_keep, (int) count_rescue, (int) count_finalize));
#endif
*out_count_keep = count_keep;
}
DUK_LOCAL void duk__sweep_stringtable_probe(duk_heap *heap, duk_size_t *out_count_keep) {
duk_hstring *h;
duk_uint_fast32_t i;
#ifdef DUK_USE_DEBUG
duk_size_t count_free = 0;
#endif
duk_size_t count_keep = 0;
DUK_DD(DUK_DDPRINT("duk__sweep_stringtable: %p", (void *) heap));
for (i = 0; i < heap->st_size; i++) {
#if defined(DUK_USE_HEAPPTR16)
h = (duk_hstring *) DUK_USE_HEAPPTR_DEC16(heap->heap_udata, heap->strtable16[i]);
#else
h = heap->strtable[i];
#endif
if (h == NULL || h == DUK_STRTAB_DELETED_MARKER(heap)) {
continue;
} else if (DUK_HEAPHDR_HAS_REACHABLE((duk_heaphdr *) h)) {
DUK_HEAPHDR_CLEAR_REACHABLE((duk_heaphdr *) h);
count_keep++;
continue;
}
#ifdef DUK_USE_DEBUG
count_free++;
#endif
#if defined(DUK_USE_REFERENCE_COUNTING)
/* Non-zero refcounts should not happen for unreachable strings,
* because we refcount finalize all unreachable objects which
* should have decreased unreachable string refcounts to zero
* (even for cycles).
*/
DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h) == 0);
#endif
DUK_DDD(DUK_DDDPRINT("sweep string, not reachable: %p", (void *) h));
/* deal with weak references first */
duk_heap_strcache_string_remove(heap, (duk_hstring *) h);
/* remove the string (mark DELETED), could also call
* duk_heap_string_remove() but that would be slow and
* pointless because we already know the slot.
*/
#if defined(DUK_USE_HEAPPTR16)
heap->strtable16[i] = heap->heapptr_deleted16;
#else
heap->strtable[i] = DUK_STRTAB_DELETED_MARKER(heap);
#endif
/* free inner references (these exist e.g. when external
* strings are enabled)
*/
duk_free_hstring_inner(heap, (duk_hstring *) h);
/* finally free the struct itself */
DUK_FREE(heap, h);
}
#ifdef DUK_USE_DEBUG
DUK_D(DUK_DPRINT("mark-and-sweep sweep stringtable: %ld freed, %ld kept",
(long) count_free, (long) count_keep));
#endif
*out_count_keep = count_keep;
}
