DUK_INTERNAL void duk_heaphdr_refcount_finalize(duk_hthread *thr, duk_heaphdr *hdr) {
DUK_ASSERT(hdr);
switch (DUK_HEAPHDR_GET_TYPE(hdr)) {
case DUK_HTYPE_OBJECT:
duk__refcount_finalize_hobject(thr, (duk_hobject *) hdr);
break;
case DUK_HTYPE_BUFFER:
/* nothing to finalize */
break;
case DUK_HTYPE_STRING:
/* cannot happen: strings are not put into refzero list (they don't even have the next/prev pointers) */
default:
DUK_UNREACHABLE();
}
}
DUK_LOCAL void duk__free_run_finalizers(duk_heap *heap) {
duk_hthread *thr;
duk_heaphdr *curr;
#ifdef DUK_USE_DEBUG
duk_size_t count_obj = 0;
#endif
DUK_ASSERT(heap != NULL);
DUK_ASSERT(heap->heap_thread != NULL);
#ifdef DUK_USE_REFERENCE_COUNTING
DUK_ASSERT(heap->refzero_list == NULL); /* refzero not running -> must be empty */
#endif
#ifdef DUK_USE_MARK_AND_SWEEP
DUK_ASSERT(heap->finalize_list == NULL); /* mark-and-sweep not running -> must be empty */
#endif
/* XXX: here again finalizer thread is the heap_thread which needs
* to be coordinated with finalizer thread fixes.
*/
thr = heap->heap_thread;
DUK_ASSERT(thr != NULL);
curr = heap->heap_allocated;
while (curr) {
if (DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT) {
/* Only objects in heap_allocated may have finalizers. Check that
* the object itself has a _Finalizer property so that we don't
* execute finalizers for e.g. Proxy objects.
*/
DUK_ASSERT(thr != NULL);
DUK_ASSERT(curr != NULL);
if (duk_hobject_hasprop_raw(thr, (duk_hobject *) curr, DUK_HTHREAD_STRING_INT_FINALIZER(thr))) {
duk_hobject_run_finalizer(thr, (duk_hobject *) curr);
}
#ifdef DUK_USE_DEBUG
count_obj++;
#endif
}
curr = DUK_HEAPHDR_GET_NEXT(curr);
}
/* Note: count includes all objects, not only those with an actual finalizer. */
#ifdef DUK_USE_DEBUG
DUK_D(DUK_DPRINT("checked %ld objects for finalizers before freeing heap", (long) count_obj));
#endif
}
static void duk__compact_object_list(duk_heap *heap, duk_hthread *thr, duk_heaphdr *start, int *p_count_check, int *p_count_compact, int *p_count_bytes_saved) {
#else
static void duk__compact_object_list(duk_heap *heap, duk_hthread *thr, duk_heaphdr *start) {
#endif
duk_heaphdr *curr;
#ifdef DUK_USE_DEBUG
size_t old_size, new_size;
#endif
duk_hobject *obj;
DUK_UNREF(heap);
curr = start;
while (curr) {
DUK_DDD(DUK_DDDPRINT("mark-and-sweep compact: %p", (void *) curr));
if (DUK_HEAPHDR_GET_TYPE(curr) != DUK_HTYPE_OBJECT) {
goto next;
}
obj = (duk_hobject *) curr;
#ifdef DUK_USE_DEBUG
old_size = DUK_HOBJECT_P_COMPUTE_SIZE(obj->e_size, obj->a_size, obj->h_size);
#endif
DUK_DD(DUK_DDPRINT("compact object: %p", (void *) obj));
duk_push_hobject((duk_context *) thr, obj);
/* XXX: disable error handlers for duration of compaction? */
duk_safe_call((duk_context *) thr, duk__protected_compact_object, 1, 0);
#ifdef DUK_USE_DEBUG
new_size = DUK_HOBJECT_P_COMPUTE_SIZE(obj->e_size, obj->a_size, obj->h_size);
#endif
#ifdef DUK_USE_DEBUG
(*p_count_compact)++;
(*p_count_bytes_saved) += old_size - new_size;
#endif
next:
curr = DUK_HEAPHDR_GET_NEXT(curr);
#ifdef DUK_USE_DEBUG
(*p_count_check)++;
#endif
}
}
static void duk__free_run_finalizers(duk_heap *heap) {
duk_heaphdr *curr;
#ifdef DUK_USE_DEBUG
duk_size_t count_obj = 0;
#endif
DUK_ASSERT(heap != NULL);
DUK_ASSERT(heap->heap_thread != NULL);
#ifdef DUK_USE_REFERENCE_COUNTING
DUK_ASSERT(heap->refzero_list == NULL); /* refzero not running -> must be empty */
#endif
#ifdef DUK_USE_MARK_AND_SWEEP
DUK_ASSERT(heap->finalize_list == NULL); /* mark-and-sweep not running -> must be empty */
#endif
/* FIXME: here again finalizer thread is the heap_thread which needs
* to be coordinated with finalizer thread fixes.
*/
curr = heap->heap_allocated;
while (curr) {
if (DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT) {
/* Only objects in heap_allocated may have finalizers. */
DUK_ASSERT(heap->heap_thread != NULL);
DUK_ASSERT(curr != NULL);
duk_hobject_run_finalizer(heap->heap_thread, (duk_hobject *) curr);
#ifdef DUK_USE_DEBUG
count_obj++;
#endif
}
curr = DUK_HEAPHDR_GET_NEXT(curr);
}
/* Note: count includes all objects, not only those with an actual finalizer. */
#ifdef DUK_USE_DEBUG
DUK_D(DUK_DPRINT("checked %d objects for finalizers before freeing heap", (int) count_obj));
#endif
}
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__refcount_finalize_hobject(duk_hthread *thr, duk_hobject *h) {
duk_uint_fast32_t i;
DUK_ASSERT(h);
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) h) == DUK_HTYPE_OBJECT);
/* XXX: better to get base and walk forwards? */
for (i = 0; i < (duk_uint_fast32_t) h->e_next; i++) {
duk_hstring *key = DUK_HOBJECT_E_GET_KEY(h, i);
if (!key) {
continue;
}
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) key);
if (DUK_HOBJECT_E_SLOT_IS_ACCESSOR(h, i)) {
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) DUK_HOBJECT_E_GET_VALUE_GETTER(h, i));
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) DUK_HOBJECT_E_GET_VALUE_SETTER(h, i));
} else {
duk_heap_tval_decref(thr, DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(h, i));
}
}
for (i = 0; i < (duk_uint_fast32_t) h->a_size; i++) {
duk_heap_tval_decref(thr, DUK_HOBJECT_A_GET_VALUE_PTR(h, i));
}
/* hash part is a 'weak reference' and does not contribute */
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) h->prototype);
if (DUK_HOBJECT_IS_COMPILEDFUNCTION(h)) {
duk_hcompiledfunction *f = (duk_hcompiledfunction *) h;
duk_tval *tv, *tv_end;
duk_hobject **funcs, **funcs_end;
DUK_ASSERT(f->data != NULL); /* compiled functions must be created 'atomically' */
tv = DUK_HCOMPILEDFUNCTION_GET_CONSTS_BASE(f);
tv_end = DUK_HCOMPILEDFUNCTION_GET_CONSTS_END(f);
while (tv < tv_end) {
duk_heap_tval_decref(thr, tv);
tv++;
}
funcs = DUK_HCOMPILEDFUNCTION_GET_FUNCS_BASE(f);
funcs_end = DUK_HCOMPILEDFUNCTION_GET_FUNCS_END(f);
while (funcs < funcs_end) {
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) *funcs);
funcs++;
}
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) f->data);
} else if (DUK_HOBJECT_IS_NATIVEFUNCTION(h)) {
duk_hnativefunction *f = (duk_hnativefunction *) h;
DUK_UNREF(f);
/* nothing to finalize */
} else if (DUK_HOBJECT_IS_THREAD(h)) {
duk_hthread *t = (duk_hthread *) h;
duk_tval *tv;
tv = t->valstack;
while (tv < t->valstack_end) {
duk_heap_tval_decref(thr, tv);
tv++;
}
for (i = 0; i < (duk_uint_fast32_t) t->callstack_top; i++) {
duk_activation *act = t->callstack + i;
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) act->func);
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) act->var_env);
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) act->lex_env);
#ifdef DUK_USE_NONSTD_FUNC_CALLER_PROPERTY
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) act->prev_caller);
#endif
}
#if 0 /* nothing now */
for (i = 0; i < (duk_uint_fast32_t) t->catchstack_top; i++) {
duk_catcher *cat = t->catchstack + i;
}
#endif
for (i = 0; i < DUK_NUM_BUILTINS; i++) {
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) t->builtins[i]);
}
duk_heap_heaphdr_decref(thr, (duk_heaphdr *) t->resumer);
}
}
void duk_heap_heaphdr_decref(duk_hthread *thr, duk_heaphdr *h) {
duk_heap *heap;
#if 0
DUK_DDD(DUK_DDDPRINT("heaphdr decref %p (%ld->%ld): %!O",
(void *) h,
(h != NULL ? (long) h->h_refcount : (long) 0),
(h != NULL ? (long) (h->h_refcount - 1) : (long) 0),
(duk_heaphdr *) h));
#endif
DUK_ASSERT(thr != NULL);
DUK_ASSERT(thr->heap != NULL);
if (!h) {
return;
}
DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
DUK_ASSERT(h->h_refcount >= 1);
if (--h->h_refcount != 0) {
return;
}
heap = thr->heap;
DUK_DDD(DUK_DDDPRINT("refzero %p: %!O", (void *) h, (duk_heaphdr *) h));
#ifdef DUK_USE_MARK_AND_SWEEP
/*
* If mark-and-sweep is running, don't process 'refzero' situations at all.
* They may happen because mark-and-sweep needs to finalize refcounts for
* each object it sweeps. Otherwise the target objects of swept objects
* would have incorrect refcounts.
*
* Note: mark-and-sweep could use a separate decref handler to avoid coming
* here at all. However, mark-and-sweep may also call finalizers, which
* can do arbitrary operations and would use this decref variant anyway.
*/
if (DUK_HEAP_HAS_MARKANDSWEEP_RUNNING(heap)) {
DUK_DDD(DUK_DDDPRINT("refzero handling suppressed when mark-and-sweep running, object: %p", (void *) h));
return;
}
#endif
switch ((duk_small_int_t) DUK_HEAPHDR_GET_TYPE(h)) {
case DUK_HTYPE_STRING:
/*
* Strings have no internal references but do have "weak"
* references in the string cache. Also note that strings
* are not on the heap_allocated list like other heap
* elements.
*/
duk_heap_strcache_string_remove(heap, (duk_hstring *) h);
duk_heap_string_remove(heap, (duk_hstring *) h);
duk_heap_free_heaphdr_raw(heap, h);
break;
case DUK_HTYPE_OBJECT:
/*
* Objects have internal references. Must finalize through
* the "refzero" work list.
*/
duk_heap_remove_any_from_heap_allocated(heap, h);
duk__queue_refzero(heap, h);
duk__refzero_free_pending(thr);
break;
case DUK_HTYPE_BUFFER:
/*
* Buffers have no internal references. However, a dynamic
* buffer has a separate allocation for the buffer. This is
* freed by duk_heap_free_heaphdr_raw().
*/
duk_heap_remove_any_from_heap_allocated(heap, h);
duk_heap_free_heaphdr_raw(heap, h);
break;
default:
DUK_D(DUK_DPRINT("invalid heap type in decref: %ld", (long) DUK_HEAPHDR_GET_TYPE(h)));
DUK_UNREACHABLE();
}
}
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 */
}
DUK_INTERNAL void duk_heaphdr_refzero(duk_hthread *thr, duk_heaphdr *h) {
duk_heap *heap;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(h != NULL);
heap = thr->heap;
DUK_DDD(DUK_DDDPRINT("refzero %p: %!O", (void *) h, (duk_heaphdr *) h));
/*
* Refzero handling is skipped entirely if (1) mark-and-sweep is
* running or (2) execution is paused in the debugger. The objects
* are left in the heap, and will be freed by mark-and-sweep or
* eventual heap destruction.
*
* This is necessary during mark-and-sweep because refcounts are also
* updated during the sweep phase (otherwise objects referenced by a
* swept object would have incorrect refcounts) which then calls here.
* This could be avoided by using separate decref macros in
* mark-and-sweep; however, mark-and-sweep also calls finalizers which
* would use the ordinary decref macros anyway and still call this
* function.
*
* This check must be enabled also when mark-and-sweep support has been
* disabled: the flag is also used in heap destruction when running
* finalizers for remaining objects, and the flag prevents objects from
* being moved around in heap linked lists.
*/
/* XXX: ideally this would be just one flag (maybe a derived one) so
* that a single bit test is sufficient to check the condition.
*/
#if defined(DUK_USE_DEBUGGER_SUPPORT)
if (DUK_UNLIKELY(DUK_HEAP_HAS_MARKANDSWEEP_RUNNING(heap) || DUK_HEAP_IS_PAUSED(heap))) {
#else
if (DUK_UNLIKELY(DUK_HEAP_HAS_MARKANDSWEEP_RUNNING(heap))) {
#endif
DUK_DDD(DUK_DDDPRINT("refzero handling suppressed when mark-and-sweep running, object: %p", (void *) h));
return;
}
switch ((duk_small_int_t) DUK_HEAPHDR_GET_TYPE(h)) {
case DUK_HTYPE_STRING:
/*
* Strings have no internal references but do have "weak"
* references in the string cache. Also note that strings
* are not on the heap_allocated list like other heap
* elements.
*/
duk_heap_strcache_string_remove(heap, (duk_hstring *) h);
duk_heap_string_remove(heap, (duk_hstring *) h);
duk_heap_free_heaphdr_raw(heap, h);
break;
case DUK_HTYPE_OBJECT:
/*
* Objects have internal references. Must finalize through
* the "refzero" work list.
*/
duk_heap_remove_any_from_heap_allocated(heap, h);
duk__queue_refzero(heap, h);
duk__refzero_free_pending(thr);
break;
case DUK_HTYPE_BUFFER:
/*
* Buffers have no internal references. However, a dynamic
* buffer has a separate allocation for the buffer. This is
* freed by duk_heap_free_heaphdr_raw().
*/
duk_heap_remove_any_from_heap_allocated(heap, h);
duk_heap_free_heaphdr_raw(heap, h);
break;
default:
DUK_D(DUK_DPRINT("invalid heap type in decref: %ld", (long) DUK_HEAPHDR_GET_TYPE(h)));
DUK_UNREACHABLE();
}
}
#if !defined(DUK_USE_FAST_REFCOUNT_DEFAULT)
DUK_INTERNAL void duk_tval_incref(duk_tval *tv) {
DUK_ASSERT(tv != NULL);
if (DUK_TVAL_NEEDS_REFCOUNT_UPDATE(tv)) {
duk_heaphdr *h = DUK_TVAL_GET_HEAPHDR(tv);
DUK_ASSERT(h != NULL);
DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
DUK_ASSERT_DISABLE(h->h_refcount >= 0);
DUK_HEAPHDR_PREINC_REFCOUNT(h);
}
}
DUK_LOCAL void duk__free_stringtable(duk_heap *heap) {
duk_uint_fast32_t i;
/* strings are only tracked by stringtable */
#if defined(DUK_USE_HEAPPTR16)
if (heap->strtable16) {
#else
if (heap->strtable) {
#endif
for (i = 0; i < (duk_uint_fast32_t) heap->st_size; i++) {
duk_hstring *e;
#if defined(DUK_USE_HEAPPTR16)
e = (duk_hstring *) DUK_USE_HEAPPTR_DEC16(heap->strtable16[i]);
#else
e = heap->strtable[i];
#endif
if (e == NULL || e == DUK_STRTAB_DELETED_MARKER(heap)) {
continue;
}
DUK_ASSERT(e != NULL);
/* strings may have inner refs (extdata) in some cases */
duk_free_hstring_inner(heap, (duk_hstring *) e);
DUK_DDD(DUK_DDDPRINT("FINALFREE (string): %!iO",
(duk_heaphdr *) e));
DUK_FREE(heap, e);
#if 0 /* not strictly necessary */
heap->strtable[i] = NULL;
#endif
}
#if defined(DUK_USE_HEAPPTR16)
DUK_FREE(heap, heap->strtable16);
#else
DUK_FREE(heap, heap->strtable);
#endif
#if 0 /* not strictly necessary */
heap->strtable = NULL;
#endif
}
}
DUK_LOCAL void duk__free_run_finalizers(duk_heap *heap) {
duk_hthread *thr;
duk_heaphdr *curr;
#ifdef DUK_USE_DEBUG
duk_size_t count_obj = 0;
#endif
DUK_ASSERT(heap != NULL);
DUK_ASSERT(heap->heap_thread != NULL);
#ifdef DUK_USE_REFERENCE_COUNTING
DUK_ASSERT(heap->refzero_list == NULL); /* refzero not running -> must be empty */
#endif
#ifdef DUK_USE_MARK_AND_SWEEP
DUK_ASSERT(heap->finalize_list == NULL); /* mark-and-sweep not running -> must be empty */
#endif
/* XXX: here again finalizer thread is the heap_thread which needs
* to be coordinated with finalizer thread fixes.
*/
thr = heap->heap_thread;
DUK_ASSERT(thr != NULL);
curr = heap->heap_allocated;
while (curr) {
if (DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT) {
/* Only objects in heap_allocated may have finalizers. Check that
* the object itself has a _Finalizer property so that we don't
* execute finalizers for e.g. Proxy objects.
*/
DUK_ASSERT(thr != NULL);
DUK_ASSERT(curr != NULL);
if (duk_hobject_hasprop_raw(thr, (duk_hobject *) curr, DUK_HTHREAD_STRING_INT_FINALIZER(thr))) {
duk_hobject_run_finalizer(thr, (duk_hobject *) curr);
}
#ifdef DUK_USE_DEBUG
count_obj++;
#endif
}
curr = DUK_HEAPHDR_GET_NEXT(curr);
}
/* Note: count includes all objects, not only those with an actual finalizer. */
#ifdef DUK_USE_DEBUG
DUK_D(DUK_DPRINT("checked %ld objects for finalizers before freeing heap", (long) count_obj));
#endif
}
DUK_LOCAL void duk__free_run_finalizers(duk_heap *heap) {
duk_hthread *thr;
duk_heaphdr *curr;
duk_uint_t round_no;
duk_size_t count_all;
duk_size_t count_finalized;
duk_size_t curr_limit;
DUK_ASSERT(heap != NULL);
DUK_ASSERT(heap->heap_thread != NULL);
#if defined(DUK_USE_REFERENCE_COUNTING)
DUK_ASSERT(heap->refzero_list == NULL); /* refzero not running -> must be empty */
#endif
#if defined(DUK_USE_MARK_AND_SWEEP)
DUK_ASSERT(heap->finalize_list == NULL); /* mark-and-sweep not running -> must be empty */
#endif
/* XXX: here again finalizer thread is the heap_thread which needs
* to be coordinated with finalizer thread fixes.
*/
thr = heap->heap_thread;
DUK_ASSERT(thr != NULL);
/* Prevent mark-and-sweep for the pending finalizers, also prevents
* refzero handling from moving objects away from the heap_allocated
* list. (The flag meaning is slightly abused here.)
*/
DUK_ASSERT(!DUK_HEAP_HAS_MARKANDSWEEP_RUNNING(heap));
DUK_HEAP_SET_MARKANDSWEEP_RUNNING(heap);
curr_limit = 0; /* suppress warning, not used */
for (round_no = 0; ; round_no++) {
curr = heap->heap_allocated;
count_all = 0;
count_finalized = 0;
while (curr) {
count_all++;
if (DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT) {
/* Only objects in heap_allocated may have finalizers. Check that
* the object itself has a _Finalizer property (own or inherited)
* so that we don't execute finalizers for e.g. Proxy objects.
*/
DUK_ASSERT(thr != NULL);
DUK_ASSERT(curr != NULL);
if (duk_hobject_hasprop_raw(thr, (duk_hobject *) curr, DUK_HTHREAD_STRING_INT_FINALIZER(thr))) {
if (!DUK_HEAPHDR_HAS_FINALIZED((duk_heaphdr *) curr)) {
DUK_ASSERT(DUK_HEAP_HAS_FINALIZER_NORESCUE(heap)); /* maps to finalizer 2nd argument */
duk_hobject_run_finalizer(thr, (duk_hobject *) curr);
count_finalized++;
}
}
}
curr = DUK_HEAPHDR_GET_NEXT(heap, curr);
}
/* Each round of finalizer execution may spawn new finalizable objects
* which is normal behavior for some applications. Allow multiple
* rounds of finalization, but use a shrinking limit based on the
* first round to detect the case where a runaway finalizer creates
* an unbounded amount of new finalizable objects. Finalizer rescue
* is not supported: the semantics are unclear because most of the
* objects being finalized here are already reachable. The finalizer
* is given a boolean to indicate that rescue is not possible.
*
* See discussion in: https://github.com/svaarala/duktape/pull/473
*/
if (round_no == 0) {
/* Cannot wrap: each object is at least 8 bytes so count is
* at most 1/8 of that.
*/
curr_limit = count_all * 2;
} else {
curr_limit = (curr_limit * 3) / 4; /* Decrease by 25% every round */
}
DUK_D(DUK_DPRINT("finalizer round %ld complete, %ld objects, tried to execute %ld finalizers, current limit is %ld",
(long) round_no, (long) count_all, (long) count_finalized, (long) curr_limit));
if (count_finalized == 0) {
DUK_D(DUK_DPRINT("no more finalizable objects, forced finalization finished"));
break;
}
if (count_finalized >= curr_limit) {
DUK_D(DUK_DPRINT("finalizer count above limit, potentially runaway finalizer; skip remaining finalizers"));
break;
}
}
DUK_ASSERT(DUK_HEAP_HAS_MARKANDSWEEP_RUNNING(heap));
DUK_HEAP_CLEAR_MARKANDSWEEP_RUNNING(heap);
}
/* Raw helper to extract internal information / statistics about a value.
* The return values are version specific and must not expose anything
* that would lead to security issues (e.g. exposing compiled function
* 'data' buffer might be an issue). Currently only counts and sizes and
* such are given so there should not be a security impact.
*/
DUK_INTERNAL duk_ret_t duk_bi_duktape_object_info(duk_context *ctx) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_tval *tv;
duk_heaphdr *h;
duk_int_t i, n;
DUK_UNREF(thr);
/* result array */
duk_push_array(ctx); /* -> [ val arr ] */
/* type tag (public) */
duk_push_int(ctx, duk_get_type(ctx, 0));
/* address */
tv = duk_get_tval(ctx, 0);
DUK_ASSERT(tv != NULL); /* because arg count is 1 */
if (DUK_TVAL_IS_HEAP_ALLOCATED(tv)) {
h = DUK_TVAL_GET_HEAPHDR(tv);
duk_push_pointer(ctx, (void *) h);
} else {
/* internal type tag */
duk_push_int(ctx, (duk_int_t) DUK_TVAL_GET_TAG(tv));
goto done;
}
DUK_ASSERT(h != NULL);
/* refcount */
#ifdef DUK_USE_REFERENCE_COUNTING
duk_push_size_t(ctx, DUK_HEAPHDR_GET_REFCOUNT(h));
#else
duk_push_undefined(ctx);
#endif
/* heaphdr size and additional allocation size, followed by
* type specific stuff (with varying value count)
*/
switch ((duk_small_int_t) DUK_HEAPHDR_GET_TYPE(h)) {
case DUK_HTYPE_STRING: {
duk_hstring *h_str = (duk_hstring *) h;
duk_push_uint(ctx, (duk_uint_t) (sizeof(duk_hstring) + DUK_HSTRING_GET_BYTELEN(h_str) + 1));
break;
}
case DUK_HTYPE_OBJECT: {
duk_hobject *h_obj = (duk_hobject *) h;
duk_small_uint_t hdr_size;
if (DUK_HOBJECT_IS_COMPILEDFUNCTION(h_obj)) {
hdr_size = (duk_small_uint_t) sizeof(duk_hcompiledfunction);
} else if (DUK_HOBJECT_IS_NATIVEFUNCTION(h_obj)) {
hdr_size = (duk_small_uint_t) sizeof(duk_hnativefunction);
} else if (DUK_HOBJECT_IS_THREAD(h_obj)) {
hdr_size = (duk_small_uint_t) sizeof(duk_hthread);
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
} else if (DUK_HOBJECT_IS_BUFFEROBJECT(h_obj)) {
hdr_size = (duk_small_uint_t) sizeof(duk_hbufferobject);
#endif
} else {
hdr_size = (duk_small_uint_t) sizeof(duk_hobject);
}
duk_push_uint(ctx, (duk_uint_t) hdr_size);
duk_push_uint(ctx, (duk_uint_t) DUK_HOBJECT_P_ALLOC_SIZE(h_obj));
duk_push_uint(ctx, (duk_uint_t) DUK_HOBJECT_GET_ESIZE(h_obj));
/* Note: e_next indicates the number of gc-reachable entries
* in the entry part, and also indicates the index where the
* next new property would be inserted. It does *not* indicate
* the number of non-NULL keys present in the object. That
* value could be counted separately but requires a pass through
* the key list.
*/
duk_push_uint(ctx, (duk_uint_t) DUK_HOBJECT_GET_ENEXT(h_obj));
duk_push_uint(ctx, (duk_uint_t) DUK_HOBJECT_GET_ASIZE(h_obj));
duk_push_uint(ctx, (duk_uint_t) DUK_HOBJECT_GET_HSIZE(h_obj));
if (DUK_HOBJECT_IS_COMPILEDFUNCTION(h_obj)) {
duk_hbuffer *h_data = (duk_hbuffer *) DUK_HCOMPILEDFUNCTION_GET_DATA(thr->heap, (duk_hcompiledfunction *) h_obj);
if (h_data) {
duk_push_uint(ctx, (duk_uint_t) DUK_HBUFFER_GET_SIZE(h_data));
} else {
duk_push_uint(ctx, 0);
}
}
break;
}
case DUK_HTYPE_BUFFER: {
duk_hbuffer *h_buf = (duk_hbuffer *) h;
if (DUK_HBUFFER_HAS_DYNAMIC(h_buf)) {
if (DUK_HBUFFER_HAS_EXTERNAL(h_buf)) {
duk_push_uint(ctx, (duk_uint_t) (sizeof(duk_hbuffer_external)));
} else {
/* When alloc_size == 0 the second allocation may not
* actually exist.
*/
duk_push_uint(ctx, (duk_uint_t) (sizeof(duk_hbuffer_dynamic)));
}
duk_push_uint(ctx, (duk_uint_t) (DUK_HBUFFER_GET_SIZE(h_buf)));
} else {
duk_push_uint(ctx, (duk_uint_t) (sizeof(duk_hbuffer_fixed) + DUK_HBUFFER_GET_SIZE(h_buf) + 1));
}
break;
}
}
done:
/* set values into ret array */
/* XXX: primitive to make array from valstack slice */
n = duk_get_top(ctx);
for (i = 2; i < n; i++) {
duk_dup(ctx, i);
duk_put_prop_index(ctx, 1, i - 2);
}
duk_dup(ctx, 1);
return 1;
}
static duk_uint8_t *duk__load_func(duk_context *ctx, duk_uint8_t *p, duk_uint8_t *p_end) {
duk_hthread *thr;
duk_hcompiledfunction *h_fun;
duk_hbuffer *h_data;
duk_size_t data_size;
duk_uint32_t count_instr, count_const, count_funcs;
duk_uint32_t n;
duk_uint32_t tmp32;
duk_small_uint_t const_type;
duk_uint8_t *fun_data;
duk_uint8_t *q;
duk_idx_t idx_base;
duk_tval *tv;
duk_uarridx_t arr_idx;
/* XXX: There's some overlap with duk_js_closure() here, but
* seems difficult to share code. Ensure that the final function
* looks the same as created by duk_js_closure().
*/
DUK_ASSERT(ctx != NULL);
thr = (duk_hthread *) ctx;
DUK_DD(DUK_DDPRINT("loading function, p=%p, p_end=%p", (void *) p, (void *) p_end));
DUK__ASSERT_LEFT(3 * 4);
count_instr = DUK_RAW_READ_U32_BE(p);
count_const = DUK_RAW_READ_U32_BE(p);
count_funcs = DUK_RAW_READ_U32_BE(p);
data_size = sizeof(duk_tval) * count_const +
sizeof(duk_hobject *) * count_funcs +
sizeof(duk_instr_t) * count_instr;
DUK_DD(DUK_DDPRINT("instr=%ld, const=%ld, funcs=%ld, data_size=%ld",
(long) count_instr, (long) count_const,
(long) count_const, (long) data_size));
/* Value stack is used to ensure reachability of constants and
* inner functions being loaded. Require enough space to handle
* large functions correctly.
*/
duk_require_stack(ctx, 2 + count_const + count_funcs);
idx_base = duk_get_top(ctx);
/* Push function object, init flags etc. This must match
* duk_js_push_closure() quite carefully.
*/
duk_push_compiledfunction(ctx);
h_fun = duk_get_hcompiledfunction(ctx, -1);
DUK_ASSERT(h_fun != NULL);
DUK_ASSERT(DUK_HOBJECT_IS_COMPILEDFUNCTION((duk_hobject *) h_fun));
DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_DATA(thr->heap, h_fun) == NULL);
DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_FUNCS(thr->heap, h_fun) == NULL);
DUK_ASSERT(DUK_HCOMPILEDFUNCTION_GET_BYTECODE(thr->heap, h_fun) == NULL);
h_fun->nregs = DUK_RAW_READ_U16_BE(p);
h_fun->nargs = DUK_RAW_READ_U16_BE(p);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
h_fun->start_line = DUK_RAW_READ_U32_BE(p);
h_fun->end_line = DUK_RAW_READ_U32_BE(p);
#else
p += 8; /* skip line info */
#endif
/* duk_hcompiledfunction flags; quite version specific */
tmp32 = DUK_RAW_READ_U32_BE(p);
DUK_HEAPHDR_SET_FLAGS((duk_heaphdr *) h_fun, tmp32);
/* standard prototype */
DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, &h_fun->obj, thr->builtins[DUK_BIDX_FUNCTION_PROTOTYPE]);
/* assert just a few critical flags */
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) h_fun) == DUK_HTYPE_OBJECT);
DUK_ASSERT(!DUK_HOBJECT_HAS_BOUND(&h_fun->obj));
DUK_ASSERT(DUK_HOBJECT_HAS_COMPILEDFUNCTION(&h_fun->obj));
DUK_ASSERT(!DUK_HOBJECT_HAS_NATIVEFUNCTION(&h_fun->obj));
DUK_ASSERT(!DUK_HOBJECT_HAS_THREAD(&h_fun->obj));
DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARRAY(&h_fun->obj));
DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(&h_fun->obj));
DUK_ASSERT(!DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(&h_fun->obj));
/* Create function 'data' buffer but don't attach it yet. */
fun_data = (duk_uint8_t *) duk_push_fixed_buffer(ctx, data_size);
DUK_ASSERT(fun_data != NULL);
/* Load bytecode instructions. */
DUK_ASSERT(sizeof(duk_instr_t) == 4);
DUK__ASSERT_LEFT(count_instr * sizeof(duk_instr_t));
#if defined(DUK_USE_INTEGER_BE)
q = fun_data + sizeof(duk_tval) * count_const + sizeof(duk_hobject *) * count_funcs;
DUK_MEMCPY((void *) q,
(const void *) p,
sizeof(duk_instr_t) * count_instr);
p += sizeof(duk_instr_t) * count_instr;
#else
q = fun_data + sizeof(duk_tval) * count_const + sizeof(duk_hobject *) * count_funcs;
for (n = count_instr; n > 0; n--) {
*((duk_instr_t *) (void *) q) = DUK_RAW_READ_U32_BE(p);
q += sizeof(duk_instr_t);
}
#endif
/* Load constants onto value stack but don't yet copy to buffer. */
for (n = count_const; n > 0; n--) {
DUK__ASSERT_LEFT(1);
const_type = DUK_RAW_READ_U8(p);
switch (const_type) {
case DUK__SER_STRING: {
p = duk__load_string_raw(ctx, p);
break;
}
case DUK__SER_NUMBER: {
/* Important to do a fastint check so that constants are
* properly read back as fastints.
*/
duk_tval tv_tmp;
duk_double_t val;
DUK__ASSERT_LEFT(8);
val = DUK_RAW_READ_DOUBLE_BE(p);
DUK_TVAL_SET_NUMBER_CHKFAST(&tv_tmp, val);
duk_push_tval(ctx, &tv_tmp);
break;
}
default: {
goto format_error;
}
}
}
/* Load inner functions to value stack, but don't yet copy to buffer. */
for (n = count_funcs; n > 0; n--) {
p = duk__load_func(ctx, p, p_end);
if (p == NULL) {
goto format_error;
}
}
/* With constants and inner functions on value stack, we can now
* atomically finish the function 'data' buffer, bump refcounts,
* etc.
*
* Here we take advantage of the value stack being just a duk_tval
* array: we can just memcpy() the constants as long as we incref
* them afterwards.
*/
h_data = (duk_hbuffer *) duk_get_hbuffer(ctx, idx_base + 1);
DUK_ASSERT(h_data != NULL);
DUK_ASSERT(!DUK_HBUFFER_HAS_DYNAMIC(h_data));
DUK_HCOMPILEDFUNCTION_SET_DATA(thr->heap, h_fun, h_data);
DUK_HBUFFER_INCREF(thr, h_data);
tv = duk_get_tval(ctx, idx_base + 2); /* may be NULL if no constants or inner funcs */
DUK_ASSERT((count_const == 0 && count_funcs == 0) || tv != NULL);
q = fun_data;
if (count_const > 0) {
/* Explicit zero size check to avoid NULL 'tv'. */
DUK_MEMCPY((void *) q, (const void *) tv, sizeof(duk_tval) * count_const);
for (n = count_const; n > 0; n--) {
DUK_TVAL_INCREF_FAST(thr, (duk_tval *) (void *) q); /* no side effects */
q += sizeof(duk_tval);
}
tv += count_const;
}
DUK_HCOMPILEDFUNCTION_SET_FUNCS(thr->heap, h_fun, (duk_hobject **) (void *) q);
for (n = count_funcs; n > 0; n--) {
duk_hobject *h_obj;
DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv));
h_obj = DUK_TVAL_GET_OBJECT(tv);
DUK_ASSERT(h_obj != NULL);
tv++;
DUK_HOBJECT_INCREF(thr, h_obj);
*((duk_hobject **) (void *) q) = h_obj;
q += sizeof(duk_hobject *);
}
DUK_HCOMPILEDFUNCTION_SET_BYTECODE(thr->heap, h_fun, (duk_instr_t *) (void *) q);
/* The function object is now reachable and refcounts are fine,
* so we can pop off all the temporaries.
*/
DUK_DDD(DUK_DDDPRINT("function is reachable, reset top; func: %!iT", duk_get_tval(ctx, idx_base)));
duk_set_top(ctx, idx_base + 1);
/* Setup function properties. */
tmp32 = DUK_RAW_READ_U32_BE(p);
duk_push_u32(ctx, tmp32);
duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_NONE);
p = duk__load_string_raw(ctx, p);
if (DUK_HOBJECT_HAS_NAMEBINDING((duk_hobject *) h_fun)) {
/* Original function instance/template had NAMEBINDING.
* Must create a lexical environment on loading to allow
* recursive functions like 'function foo() { foo(); }'.
*/
duk_hobject *proto;
proto = thr->builtins[DUK_BIDX_GLOBAL_ENV];
(void) duk_push_object_helper_proto(ctx,
DUK_HOBJECT_FLAG_EXTENSIBLE |
DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_DECENV),
proto);
duk_dup(ctx, -2); /* -> [ func funcname env funcname ] */
duk_dup(ctx, idx_base); /* -> [ func funcname env funcname func ] */
duk_xdef_prop(ctx, -3, DUK_PROPDESC_FLAGS_NONE); /* -> [ func funcname env ] */
duk_xdef_prop_stridx(ctx, idx_base, DUK_STRIDX_INT_LEXENV, DUK_PROPDESC_FLAGS_WC);
/* since closure has NEWENV, never define DUK_STRIDX_INT_VARENV, as it
* will be ignored anyway
*/
}
duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_NAME, DUK_PROPDESC_FLAGS_NONE);
p = duk__load_string_raw(ctx, p);
duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_FILE_NAME, DUK_PROPDESC_FLAGS_WC);
duk_push_object(ctx);
duk_dup(ctx, -2);
duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_CONSTRUCTOR, DUK_PROPDESC_FLAGS_WC); /* func.prototype.constructor = func */
duk_compact(ctx, -1);
duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_PROTOTYPE, DUK_PROPDESC_FLAGS_W);
p = duk__load_buffer_raw(ctx, p);
duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_PC2LINE, DUK_PROPDESC_FLAGS_WC);
duk_push_object(ctx); /* _Varmap */
for (;;) {
/* XXX: awkward */
p = duk__load_string_raw(ctx, p);
if (duk_get_length(ctx, -1) == 0) {
duk_pop(ctx);
break;
}
tmp32 = DUK_RAW_READ_U32_BE(p);
duk_push_u32(ctx, tmp32);
duk_put_prop(ctx, -3);
}
duk_compact(ctx, -1);
duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_VARMAP, DUK_PROPDESC_FLAGS_NONE);
duk_push_array(ctx); /* _Formals */
for (arr_idx = 0; ; arr_idx++) {
/* XXX: awkward */
p = duk__load_string_raw(ctx, p);
if (duk_get_length(ctx, -1) == 0) {
duk_pop(ctx);
break;
}
duk_put_prop_index(ctx, -2, arr_idx);
}
duk_compact(ctx, -1);
duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_FORMALS, DUK_PROPDESC_FLAGS_NONE);
/* Return with final function pushed on stack top. */
DUK_DD(DUK_DDPRINT("final loaded function: %!iT", duk_get_tval(ctx, -1)));
DUK_ASSERT_TOP(ctx, idx_base + 1);
return p;
format_error:
return NULL;
}
DUK_INTERNAL void duk_heaphdr_refzero(duk_hthread *thr, duk_heaphdr *h) {
duk_heap *heap;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(h != NULL);
heap = thr->heap;
DUK_DDD(DUK_DDDPRINT("refzero %p: %!O", (void *) h, (duk_heaphdr *) h));
/*
* If mark-and-sweep is running, don't process 'refzero' situations at all.
* They may happen because mark-and-sweep needs to finalize refcounts for
* each object it sweeps. Otherwise the target objects of swept objects
* would have incorrect refcounts.
*
* This check must be enabled also when mark-and-sweep support has been
* disabled: the flag is also used in heap destruction when running
* finalizers for remaining objects, and the flag prevents objects from
* being moved around in heap linked lists.
*
* Note: mark-and-sweep could use a separate decref handler to avoid coming
* here at all. However, mark-and-sweep may also call finalizers, which
* can do arbitrary operations and would use this decref variant anyway.
*/
if (DUK_UNLIKELY(DUK_HEAP_HAS_MARKANDSWEEP_RUNNING(heap))) {
DUK_DDD(DUK_DDDPRINT("refzero handling suppressed when mark-and-sweep running, object: %p", (void *) h));
return;
}
switch ((duk_small_int_t) DUK_HEAPHDR_GET_TYPE(h)) {
case DUK_HTYPE_STRING:
/*
* Strings have no internal references but do have "weak"
* references in the string cache. Also note that strings
* are not on the heap_allocated list like other heap
* elements.
*/
duk_heap_strcache_string_remove(heap, (duk_hstring *) h);
duk_heap_string_remove(heap, (duk_hstring *) h);
duk_heap_free_heaphdr_raw(heap, h);
break;
case DUK_HTYPE_OBJECT:
/*
* Objects have internal references. Must finalize through
* the "refzero" work list.
*/
duk_heap_remove_any_from_heap_allocated(heap, h);
duk__queue_refzero(heap, h);
duk__refzero_free_pending(thr);
break;
case DUK_HTYPE_BUFFER:
/*
* Buffers have no internal references. However, a dynamic
* buffer has a separate allocation for the buffer. This is
* freed by duk_heap_free_heaphdr_raw().
*/
duk_heap_remove_any_from_heap_allocated(heap, h);
duk_heap_free_heaphdr_raw(heap, h);
break;
default:
DUK_D(DUK_DPRINT("invalid heap type in decref: %ld", (long) DUK_HEAPHDR_GET_TYPE(h)));
DUK_UNREACHABLE();
}
}
DUK_LOCAL void duk__refcount_finalize_hobject(duk_hthread *thr, duk_hobject *h) {
duk_uint_fast32_t i;
DUK_ASSERT(h);
DUK_ASSERT(DUK_HEAPHDR_GET_TYPE((duk_heaphdr *) h) == DUK_HTYPE_OBJECT);
/* XXX: better to get base and walk forwards? */
for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ENEXT(h); i++) {
duk_hstring *key = DUK_HOBJECT_E_GET_KEY(thr->heap, h, i);
if (!key) {
continue;
}
duk_heaphdr_decref(thr, (duk_heaphdr *) key);
if (DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, h, i)) {
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) DUK_HOBJECT_E_GET_VALUE_GETTER(thr->heap, h, i));
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) DUK_HOBJECT_E_GET_VALUE_SETTER(thr->heap, h, i));
} else {
duk_tval_decref(thr, DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, h, i));
}
}
for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ASIZE(h); i++) {
duk_tval_decref(thr, DUK_HOBJECT_A_GET_VALUE_PTR(thr->heap, h, i));
}
/* hash part is a 'weak reference' and does not contribute */
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h));
/* XXX: rearrange bits to allow a switch case to be used here? */
/* XXX: add a fast path for objects (and arrays)? */
/* DUK_HOBJECT_IS_ARRAY(h): needs no special handling now as there are
* no extra fields in need of decref.
*/
if (DUK_HOBJECT_IS_COMPFUNC(h)) {
duk_hcompfunc *f = (duk_hcompfunc *) h;
duk_tval *tv, *tv_end;
duk_hobject **funcs, **funcs_end;
DUK_ASSERT(DUK_HCOMPFUNC_GET_DATA(thr->heap, f) != NULL); /* compiled functions must be created 'atomically' */
tv = DUK_HCOMPFUNC_GET_CONSTS_BASE(thr->heap, f);
tv_end = DUK_HCOMPFUNC_GET_CONSTS_END(thr->heap, f);
while (tv < tv_end) {
duk_tval_decref(thr, tv);
tv++;
}
funcs = DUK_HCOMPFUNC_GET_FUNCS_BASE(thr->heap, f);
funcs_end = DUK_HCOMPFUNC_GET_FUNCS_END(thr->heap, f);
while (funcs < funcs_end) {
duk_heaphdr_decref(thr, (duk_heaphdr *) *funcs);
funcs++;
}
duk_heaphdr_decref(thr, (duk_heaphdr *) DUK_HCOMPFUNC_GET_DATA(thr->heap, f));
} else if (DUK_HOBJECT_IS_NATFUNC(h)) {
duk_hnatfunc *f = (duk_hnatfunc *) h;
DUK_UNREF(f);
/* nothing to finalize */
} else if (DUK_HOBJECT_IS_BUFOBJ(h)) {
duk_hbufobj *b = (duk_hbufobj *) h;
if (b->buf) {
duk_heaphdr_decref(thr, (duk_heaphdr *) b->buf);
}
} else if (DUK_HOBJECT_IS_THREAD(h)) {
duk_hthread *t = (duk_hthread *) h;
duk_tval *tv;
tv = t->valstack;
while (tv < t->valstack_top) {
duk_tval_decref(thr, tv);
tv++;
}
for (i = 0; i < (duk_uint_fast32_t) t->callstack_top; i++) {
duk_activation *act = t->callstack + i;
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) DUK_ACT_GET_FUNC(act));
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) act->var_env);
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) act->lex_env);
#ifdef DUK_USE_NONSTD_FUNC_CALLER_PROPERTY
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) act->prev_caller);
#endif
}
#if 0 /* nothing now */
for (i = 0; i < (duk_uint_fast32_t) t->catchstack_top; i++) {
duk_catcher *cat = t->catchstack + i;
}
#endif
for (i = 0; i < DUK_NUM_BUILTINS; i++) {
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) t->builtins[i]);
}
duk_heaphdr_decref_allownull(thr, (duk_heaphdr *) t->resumer);
}
}
/* Raw helper to extract internal information / statistics about a value.
* The return values are version specific and must not expose anything
* that would lead to security issues (e.g. exposing compiled function
* 'data' buffer might be an issue). Currently only counts and sizes and
* such are given so there should not be a security impact.
*/
duk_ret_t duk_bi_duktape_object_info(duk_context *ctx) {
duk_tval *tv;
duk_heaphdr *h;
duk_int_t i, n;
tv = duk_get_tval(ctx, 0);
DUK_ASSERT(tv != NULL); /* because arg count is 1 */
duk_push_array(ctx); /* -> [ val arr ] */
/* type tag (public) */
duk_push_int(ctx, duk_get_type(ctx, 0));
/* address */
if (DUK_TVAL_IS_HEAP_ALLOCATED(tv)) {
h = DUK_TVAL_GET_HEAPHDR(tv);
duk_push_pointer(ctx, (void *) h);
} else {
goto done;
}
DUK_ASSERT(h != NULL);
/* refcount */
#ifdef DUK_USE_REFERENCE_COUNTING
duk_push_int(ctx, DUK_HEAPHDR_GET_REFCOUNT(h));
#else
duk_push_undefined(ctx);
#endif
/* heaphdr size and additional allocation size, followed by
* type specific stuff (with varying value count)
*/
switch ((duk_small_int_t) DUK_HEAPHDR_GET_TYPE(h)) {
case DUK_HTYPE_STRING: {
duk_hstring *h_str = (duk_hstring *) h;
duk_push_int(ctx, (int) (sizeof(duk_hstring) + DUK_HSTRING_GET_BYTELEN(h_str) + 1));
break;
}
case DUK_HTYPE_OBJECT: {
duk_hobject *h_obj = (duk_hobject *) h;
duk_int_t hdr_size;
if (DUK_HOBJECT_IS_COMPILEDFUNCTION(h_obj)) {
hdr_size = (duk_int_t) sizeof(duk_hcompiledfunction);
} else if (DUK_HOBJECT_IS_NATIVEFUNCTION(h_obj)) {
hdr_size = (duk_int_t) sizeof(duk_hnativefunction);
} else if (DUK_HOBJECT_IS_THREAD(h_obj)) {
hdr_size = (duk_int_t) sizeof(duk_hthread);
} else {
hdr_size = (duk_int_t) sizeof(duk_hobject);
}
duk_push_int(ctx, (int) hdr_size);
duk_push_int(ctx, (int) DUK_HOBJECT_E_ALLOC_SIZE(h_obj));
duk_push_int(ctx, (int) h_obj->e_size);
duk_push_int(ctx, (int) h_obj->e_used);
duk_push_int(ctx, (int) h_obj->a_size);
duk_push_int(ctx, (int) h_obj->h_size);
if (DUK_HOBJECT_IS_COMPILEDFUNCTION(h_obj)) {
duk_hbuffer *h_data = ((duk_hcompiledfunction *) h_obj)->data;
if (h_data) {
duk_push_int(ctx, DUK_HBUFFER_GET_SIZE(h_data));
} else {
duk_push_int(ctx, 0);
}
}
break;
}
case DUK_HTYPE_BUFFER: {
duk_hbuffer *h_buf = (duk_hbuffer *) h;
if (DUK_HBUFFER_HAS_DYNAMIC(h_buf)) {
/* XXX: when usable_size == 0, dynamic buf ptr may now be NULL, in which case
* the second allocation does not exist.
*/
duk_hbuffer_dynamic *h_dyn = (duk_hbuffer_dynamic *) h;
duk_push_int(ctx, (int) (sizeof(duk_hbuffer_dynamic)));
duk_push_int(ctx, (int) (DUK_HBUFFER_DYNAMIC_GET_ALLOC_SIZE(h_dyn)));
} else {
duk_push_int(ctx, (int) (sizeof(duk_hbuffer_fixed) + DUK_HBUFFER_GET_SIZE(h_buf) + 1));
}
break;
}
}
done:
/* set values into ret array */
/* FIXME: primitive to make array from valstack slice */
n = duk_get_top(ctx);
for (i = 2; i < n; i++) {
duk_dup(ctx, i);
duk_put_prop_index(ctx, 1, i - 2);
}
duk_dup(ctx, 1);
return 1;
}
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;
}
