DUK_LOCAL void duk__assert_valid_refcounts(duk_heap *heap) {
	duk_heaphdr *hdr = heap->heap_allocated;
	while (hdr) {
		if (DUK_HEAPHDR_GET_REFCOUNT(hdr) == 0 &&
		    DUK_HEAPHDR_HAS_FINALIZED(hdr)) {
			/* An object may be in heap_allocated list with a zero
			 * refcount if it has just been finalized and is waiting
			 * to be collected by the next cycle.
			 */
		} else if (DUK_HEAPHDR_GET_REFCOUNT(hdr) == 0) {
			/* An object may be in heap_allocated list with a zero
			 * refcount also if it is a temporary object created by
			 * a finalizer; because finalization now runs inside
			 * mark-and-sweep, such objects will not be queued to
			 * refzero_list and will thus appear here with refcount
			 * zero.
			 */
#if 0  /* this case can no longer occur because refcount is unsigned */
		} else if (DUK_HEAPHDR_GET_REFCOUNT(hdr) < 0) {
			DUK_D(DUK_DPRINT("invalid refcount: %ld, %p -> %!O",
			                 (hdr != NULL ? (long) DUK_HEAPHDR_GET_REFCOUNT(hdr) : (long) 0),
			                 (void *) hdr, (duk_heaphdr *) hdr));
			DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(hdr) > 0);
#endif
		}
		hdr = DUK_HEAPHDR_GET_NEXT(heap, hdr);
	}
}
Exemple #2
0
DUK_INTERNAL void duk_heaphdr_incref(duk_heaphdr *h) {
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
	DUK_ASSERT_DISABLE(DUK_HEAPHDR_GET_REFCOUNT(h) >= 0);

	DUK_HEAPHDR_PREINC_REFCOUNT(h);
}
		/* 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__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_hstring(duk__dprint_state *st, duk_hstring *h, duk_bool_t quotes) {
	duk_fixedbuffer *fb = st->fb;
	const duk_uint8_t *p;
	const duk_uint8_t *p_end;

	/* terminal type: no depth check */

	if (duk_fb_is_full(fb)) {
		return;
	}

	duk__print_shared_heaphdr_string(st, &h->hdr);

	if (!h) {
		duk_fb_put_cstring(fb, "NULL");
		return;
	}

	p = DUK_HSTRING_GET_DATA(h);
	p_end = p + DUK_HSTRING_GET_BYTELEN(h);

	if (p_end > p && p[0] == DUK_ASC_UNDERSCORE) {
		/* if property key begins with underscore, encode it with
		 * forced quotes (e.g. "_Foo") to distinguish it from encoded
		 * internal properties (e.g. \xffBar -> _Bar).
		 */
		quotes = 1;
	}

	if (quotes) {
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_DOUBLEQUOTE);
	}
	while (p < p_end) {
		duk_uint8_t ch = *p++;

		/* two special escapes: '\' and '"', other printables as is */
		if (ch == '\\') {
			duk_fb_sprintf(fb, "\\\\");
		} else if (ch == '"') {
			duk_fb_sprintf(fb, "\\\"");
		} else if (ch >= 0x20 && ch <= 0x7e) {
			duk_fb_put_byte(fb, ch);
		} else if (ch == 0xff && !quotes) {
			/* encode \xffBar as _Bar if no quotes are applied, this is for
			 * readable internal keys.
			 */
			duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_UNDERSCORE);
		} else {
			duk_fb_sprintf(fb, "\\x%02lx", (unsigned long) ch);
		}
	}
	if (quotes) {
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_DOUBLEQUOTE);
	}
#if defined(DUK_USE_REFERENCE_COUNTING)
	/* XXX: limit to quoted strings only, to save keys from being cluttered? */
	duk_fb_sprintf(fb, "/%lu", (unsigned long) DUK_HEAPHDR_GET_REFCOUNT(&h->hdr));
#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;
}
Exemple #7
0
		/*
		 *  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_IS_HEAP_ALLOCATED(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);
	}
}
#endif

#if 0  /* unused */
DUK_INTERNAL void duk_tval_incref_allownull(duk_tval *tv) {
	if (tv == NULL) {
		return;
	}
	if (DUK_TVAL_IS_HEAP_ALLOCATED(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);
	}
}
#endif

DUK_INTERNAL void duk_tval_decref(duk_hthread *thr, duk_tval *tv) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_IS_HEAP_ALLOCATED(tv)) {
		duk_heaphdr *h = DUK_TVAL_GET_HEAPHDR(tv);
		DUK_ASSERT(h != NULL);
		DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
		duk_heaphdr_decref(thr, h);
	}
}

#if 0  /* unused */
DUK_INTERNAL void duk_tval_decref_allownull(duk_hthread *thr, duk_tval *tv) {
	DUK_ASSERT(thr != NULL);

	if (tv == NULL) {
		return;
	}
	if (DUK_TVAL_IS_HEAP_ALLOCATED(tv)) {
		duk_heaphdr *h = DUK_TVAL_GET_HEAPHDR(tv);
		DUK_ASSERT(h != NULL);
		DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
		duk_heaphdr_decref(thr, h);
	}
}
#endif

#if !defined(DUK_USE_FAST_REFCOUNT_DEFAULT)
DUK_INTERNAL void duk_heaphdr_incref(duk_heaphdr *h) {
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
	DUK_ASSERT_DISABLE(DUK_HEAPHDR_GET_REFCOUNT(h) >= 0);

	DUK_HEAPHDR_PREINC_REFCOUNT(h);
}
#endif

#if 0  /* unused */
DUK_INTERNAL void duk_heaphdr_incref_allownull(duk_heaphdr *h) {
	if (h == NULL) {
		return;
	}
	DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
	DUK_ASSERT_DISABLE(DUK_HEAPHDR_GET_REFCOUNT(h) >= 0);

	DUK_HEAPHDR_PREINC_REFCOUNT(h);
}
static void duk__dump_stringtable(duk_heap *heap) {
	duk_uint_fast32_t i;
	char buf[64+1];

	DUK_D(DUK_DPRINT("stringtable %p, used %ld, size %ld, load %ld%%",
	                 (void *) heap->st,
	                 (long) heap->st_used,
	                 (long) heap->st_size,
	                 (long) (((double) heap->st_used) / ((double) heap->st_size) * 100.0)));

	for (i = 0; i < (duk_uint_fast32_t) heap->st_size; i++) {
		duk_hstring *e = heap->st[i];

		if (!e) {
			DUK_D(DUK_DPRINT("  [%ld]: NULL", (long) i));
		} else if (e == DUK_STRTAB_DELETED_MARKER(heap)) {
			DUK_D(DUK_DPRINT("  [%ld]: DELETED", (long) i));
		} else {
			duk__sanitize_snippet(buf, sizeof(buf), e);

#ifdef DUK_USE_REFERENCE_COUNTING
			DUK_D(DUK_DPRINT("  [%ld]: %p (flags: 0x%08lx, ref: %ld) '%s', strhash=0x%08lx, blen=%ld, clen=%ld, "
			                 "arridx=%ld, internal=%ld, reserved_word=%ld, strict_reserved_word=%ld, eval_or_arguments=%ld",
			                 (long) i,
			                 (void *) e,
			                 (unsigned long) DUK_HEAPHDR_GET_FLAGS((duk_heaphdr *) e),
			                 (long) DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) e),
			                 (const char *) buf,
			                 (unsigned long) e->hash,
			                 (long) e->blen,
			                 (long) e->clen,
			                 (long) (DUK_HSTRING_HAS_ARRIDX(e) ? 1 : 0),
			                 (long) (DUK_HSTRING_HAS_INTERNAL(e) ? 1 : 0),
			                 (long) (DUK_HSTRING_HAS_RESERVED_WORD(e) ? 1 : 0),
			                 (long) (DUK_HSTRING_HAS_STRICT_RESERVED_WORD(e) ? 1 : 0),
			                 (long) (DUK_HSTRING_HAS_EVAL_OR_ARGUMENTS(e) ? 1 : 0)));
#else
			DUK_D(DUK_DPRINT("  [%ld]: %p (flags: 0x%08lx) '%s', strhash=0x%08lx, blen=%ld, clen=%ld, "
			                 "arridx=%ld, internal=%ld, reserved_word=%ld, strict_reserved_word=%ld, eval_or_arguments=%ld",
			                 (long) i,
			                 (void *) e,
			                 (unsigned long) DUK_HEAPHDR_GET_FLAGS((duk_heaphdr *) e),
			                 (const char *) buf,
			                 (long) e->hash,
			                 (long) e->blen,
			                 (long) e->clen,
			                 (long) (DUK_HSTRING_HAS_ARRIDX(e) ? 1 : 0),
			                 (long) (DUK_HSTRING_HAS_INTERNAL(e) ? 1 : 0),
			                 (long) (DUK_HSTRING_HAS_RESERVED_WORD(e) ? 1 : 0),
			                 (long) (DUK_HSTRING_HAS_STRICT_RESERVED_WORD(e) ? 1 : 0),
			                 (long) (DUK_HSTRING_HAS_EVAL_OR_ARGUMENTS(e) ? 1 : 0)));
#endif
		}
	}
}
Exemple #9
0
DUK_INTERNAL void duk_heaphdr_decref(duk_hthread *thr, duk_heaphdr *h) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
	DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(h) >= 1);

	if (DUK_HEAPHDR_PREDEC_REFCOUNT(h) != 0) {
		return;
	}
	duk_heaphdr_refzero(thr, h);
}
static void dump_stringtable(duk_heap *heap) {
	duk_uint32_t i;
	char buf[64+1];

	DUK_DPRINT("stringtable %p, used %d, size %d, load %d%%",
	           (void *) heap->st,
	           (int) heap->st_used,
	           (int) heap->st_size,
	           (int) (((double) heap->st_used) / ((double) heap->st_size) * 100.0));

	for (i = 0; i < heap->st_size; i++) {
		duk_hstring *e = heap->st[i];

		if (!e) {
			DUK_DPRINT("  [%d]: NULL", i);
		} else if (e == DUK_STRTAB_DELETED_MARKER(heap)) {
			DUK_DPRINT("  [%d]: DELETED", i);
		} else {
			sanitize_snippet(buf, sizeof(buf), e);

			/* FIXME: all string flags not printed now */

#ifdef DUK_USE_REFERENCE_COUNTING
			DUK_DPRINT("  [%d]: %p (flags: 0x%08x, ref: %d) '%s', strhash=0x%08x, blen=%d, clen=%d, arridx=%d, internal=%d",
			           i,
			           (void *) e,
			           (int) DUK_HEAPHDR_GET_FLAGS((duk_heaphdr *) e),
			           (int) DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) e),
			           buf,
			           (int) e->hash,
			           (int) e->blen,
			           (int) e->clen,
			           DUK_HSTRING_HAS_ARRIDX(e) ? 1 : 0,
			           DUK_HSTRING_HAS_INTERNAL(e) ? 1 : 0);
#else
			DUK_DPRINT("  [%d]: %p (flags: 0x%08x) '%s', strhash=0x%08x, blen=%d, clen=%d, arridx=%d, internal=%d",
			           i,
			           (void *) e,
			           (int) DUK_HEAPHDR_GET_FLAGS((duk_heaphdr *) e),
			           buf,
			           (int) e->hash,
			           (int) e->blen,
			           (int) e->clen,
			           DUK_HSTRING_HAS_ARRIDX(e) ? 1 : 0,
			           DUK_HSTRING_HAS_INTERNAL(e) ? 1 : 0);
#endif
		}
	}
}
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__print_hbuffer(duk__dprint_state *st, duk_hbuffer *h) {
	duk_fixedbuffer *fb = st->fb;
	duk_size_t i, n;
	duk_uint8_t *p;

	if (duk_fb_is_full(fb)) {
		return;
	}

	/* terminal type: no depth check */

	if (!h) {
		duk_fb_put_cstring(fb, "NULL");
		return;
	}

	if (DUK_HBUFFER_HAS_DYNAMIC(h)) {
		if (DUK_HBUFFER_HAS_EXTERNAL(h)) {
			duk_hbuffer_external *g = (duk_hbuffer_external *) h;
			duk_fb_sprintf(fb, "buffer:external:%p:%ld",
			               (void *) DUK_HBUFFER_EXTERNAL_GET_DATA_PTR(NULL, g),
			               (long) DUK_HBUFFER_EXTERNAL_GET_SIZE(g));
		} else {
			duk_hbuffer_dynamic *g = (duk_hbuffer_dynamic *) h;
			duk_fb_sprintf(fb, "buffer:dynamic:%p:%ld",
			               (void *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(NULL, g),
			               (long) DUK_HBUFFER_DYNAMIC_GET_SIZE(g));
		}
	} else {
		duk_fb_sprintf(fb, "buffer:fixed:%ld", (long) DUK_HBUFFER_GET_SIZE(h));
	}

#if defined(DUK_USE_REFERENCE_COUNTING)
	duk_fb_sprintf(fb, "/%lu", (unsigned long) DUK_HEAPHDR_GET_REFCOUNT(&h->hdr));
#endif

	if (st->hexdump) {
		duk_fb_sprintf(fb, "=[");
		n = DUK_HBUFFER_GET_SIZE(h);
		p = (duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR(NULL, h);
		for (i = 0; i < n; i++) {
			duk_fb_sprintf(fb, "%02lx", (unsigned long) p[i]);
		}
		duk_fb_sprintf(fb, "]");
	}
}
DUK_INTERNAL void duk_heap_heaphdr_incref(duk_heaphdr *h) {
#if 0
	DUK_DDD(DUK_DDDPRINT("heaphdr incref %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

	if (!h) {
		return;
	}
	DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
	DUK_ASSERT_DISABLE(DUK_HEAPHDR_GET_REFCOUNT(h) >= 0);

	DUK_HEAPHDR_PREINC_REFCOUNT(h);
}
DUK_INTERNAL void duk_heaphdr_decref(duk_hthread *thr, duk_heaphdr *h) {
	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(thr->heap != NULL);
	DUK_ASSERT(h != NULL);
	DUK_ASSERT(DUK_HEAPHDR_HTYPE_VALID(h));
	DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT(h) >= 1);

#if defined(DUK_USE_ROM_OBJECTS)
	if (DUK_HEAPHDR_HAS_READONLY(h)) {
		return;
	}
#endif
	if (DUK_HEAPHDR_PREDEC_REFCOUNT(h) != 0) {
		return;
	}
	duk_heaphdr_refzero(thr, h);
}
int duk_builtin_duk_object_refc(duk_context *ctx) {
#ifdef DUK_USE_REFERENCE_COUNTING
	duk_tval *tv = duk_get_tval(ctx, 0);
	duk_heaphdr *h;
	if (!tv) {
		return 0;
	}
	if (!DUK_TVAL_IS_HEAP_ALLOCATED(tv)) {
		return 0;
	}
	h = DUK_TVAL_GET_HEAPHDR(tv);
	duk_push_int(ctx, DUK_HEAPHDR_GET_REFCOUNT(h));
	return 1;
#else
	return 0;
#endif
}
static void duk__dump_indented(duk_heaphdr *obj, int index) {
#ifdef DUK_USE_REFERENCE_COUNTING
	DUK_D(DUK_DPRINT("  [%ld]: %p %s (flags: 0x%08lx, ref: %ld) -> %!O",
	                 (long) index,
	                 (void *) obj,
	                 (const char *) duk__get_heap_type_string(obj),
	                 (unsigned long) DUK_HEAPHDR_GET_FLAGS(obj),
	                 (long) DUK_HEAPHDR_GET_REFCOUNT(obj),
	                 (duk_heaphdr *) obj));
#else
	DUK_D(DUK_DPRINT("  [%ld]: %p %s (flags: 0x%08lx) -> %!O",
	                 (long) index,
	                 (void *) obj,
	                 (const char *) duk__get_heap_type_string(obj),
	                 (unsigned long) DUK_HEAPHDR_GET_FLAGS(obj),
	                 (duk_heaphdr *) obj));
#endif
}
static void dump_indented(duk_heaphdr *obj, int index) {
#ifdef DUK_USE_REFERENCE_COUNTING
	DUK_DPRINT("  [%d]: %p %s (flags: 0x%08x, ref: %d) -> %!O",
	           index,
	           (void *) obj,
	           get_heap_type_string(obj),
	           (int) DUK_HEAPHDR_GET_FLAGS(obj),
	           DUK_HEAPHDR_GET_REFCOUNT(obj),
	           obj);
#else
	DUK_DPRINT("  [%d]: %p %s (flags: 0x%08x) -> %!O",
	           index,
	           (void *) obj,
	           get_heap_type_string(obj),
	           (int) DUK_HEAPHDR_GET_FLAGS(obj),
	           obj);
#endif
}
Exemple #18
0
/* 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;
}
/* 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;
}
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;
}
DUK_LOCAL 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(DUK_HEAPHDR_GET_REFCOUNT(h1) == 0);
			DUK_HEAPHDR_PREINC_REFCOUNT(h1);  /* bump refcount to prevent refzero during finalizer processing */

			duk_hobject_run_finalizer(thr, obj);  /* must never longjmp */

			DUK_HEAPHDR_PREDEC_REFCOUNT(h1);  /* remove artificial bump */
			DUK_ASSERT_DISABLE(h1->h_refcount >= 0);  /* refcount is unsigned, so always true */

			if (DUK_HEAPHDR_GET_REFCOUNT(h1) != 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 */
}
Exemple #22
0
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_INTERNAL 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(DUK_HEAPHDR_GET_REFCOUNT(h) >= 1);

	if (DUK_HEAPHDR_PREDEC_REFCOUNT(h) != 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();
	}
}
DUK_LOCAL void duk__print_hobject(duk__dprint_state *st, duk_hobject *h) {
	duk_fixedbuffer *fb = st->fb;
	duk_uint_fast32_t i;
	duk_tval *tv;
	duk_hstring *key;
	duk_bool_t first = 1;
	const char *brace1 = "{";
	const char *brace2 = "}";
	duk_bool_t pushed_loopstack = 0;

	if (duk_fb_is_full(fb)) {
		return;
	}

	duk__print_shared_heaphdr(st, &h->hdr);

	if (h && DUK_HOBJECT_HAS_ARRAY_PART(h)) {
		brace1 = "[";
		brace2 = "]";
	}

	if (!h) {
		duk_fb_put_cstring(fb, "NULL");
		goto finished;
	}

	if (st->depth >= st->depth_limit) {
		const char *subtype = "generic";

		if (DUK_HOBJECT_IS_COMPFUNC(h)) {
			subtype = "compfunc";
		} else if (DUK_HOBJECT_IS_NATFUNC(h)) {
			subtype = "natfunc";
		} else if (DUK_HOBJECT_IS_THREAD(h)) {
			subtype = "thread";
		} else if (DUK_HOBJECT_IS_BUFOBJ(h)) {
			subtype = "bufobj";
		} else if (DUK_HOBJECT_IS_ARRAY(h)) {
			subtype = "array";
		}
		duk_fb_sprintf(fb, "%sobject/%s %p%s", (const char *) brace1, subtype, (void *) h, (const char *) brace2);
		return;
	}

	for (i = 0; i < (duk_uint_fast32_t) st->loop_stack_index; i++) {
		if (st->loop_stack[i] == h) {
			duk_fb_sprintf(fb, "%sLOOP:%p%s", (const char *) brace1, (void *) h, (const char *) brace2);
			return;
		}
	}

	/* after this, return paths should 'goto finished' for decrement */
	st->depth++;

	if (st->loop_stack_index >= st->loop_stack_limit) {
		duk_fb_sprintf(fb, "%sOUT-OF-LOOP-STACK%s", (const char *) brace1, (const char *) brace2);
		goto finished;
	}
	st->loop_stack[st->loop_stack_index++] = h;
	pushed_loopstack = 1;

	/*
	 *  Notation: double underscore used for internal properties which are not
	 *  stored in the property allocation (e.g. '__valstack').
	 */

	duk_fb_put_cstring(fb, brace1);

	if (DUK_HOBJECT_GET_PROPS(NULL, h)) {
		duk_uint32_t a_limit;

		a_limit = DUK_HOBJECT_GET_ASIZE(h);
		if (st->internal) {
			/* dump all allocated entries, unused entries print as 'unused',
			 * note that these may extend beyond current 'length' and look
			 * a bit funny.
			 */
		} else {
			/* leave out trailing 'unused' elements */
			while (a_limit > 0) {
				tv = DUK_HOBJECT_A_GET_VALUE_PTR(NULL, h, a_limit - 1);
				if (!DUK_TVAL_IS_UNUSED(tv)) {
					break;
				}
				a_limit--;
			}
		}

		for (i = 0; i < a_limit; i++) {
			tv = DUK_HOBJECT_A_GET_VALUE_PTR(NULL, h, i);
			DUK__COMMA();
			duk__print_tval(st, tv);
		}
		for (i = 0; i < DUK_HOBJECT_GET_ENEXT(h); i++) {
			key = DUK_HOBJECT_E_GET_KEY(NULL, h, i);
			if (!key) {
				continue;
			}
			if (!st->internal && DUK_HSTRING_HAS_HIDDEN(key)) {
				continue;
			}
			DUK__COMMA();
			duk__print_hstring(st, key, 0);
			duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_COLON);
			if (DUK_HOBJECT_E_SLOT_IS_ACCESSOR(NULL, h, i)) {
				duk_fb_sprintf(fb, "[get:%p,set:%p]",
				               (void *) DUK_HOBJECT_E_GET_VALUE(NULL, h, i).a.get,
				               (void *) DUK_HOBJECT_E_GET_VALUE(NULL, h, i).a.set);
			} else {
				tv = &DUK_HOBJECT_E_GET_VALUE(NULL, h, i).v;
				duk__print_tval(st, tv);
			}
			if (st->heavy) {
				duk_fb_sprintf(fb, "<%02lx>", (unsigned long) DUK_HOBJECT_E_GET_FLAGS(NULL, h, i));
			}
		}
	}
	if (st->internal) {
		if (DUK_HOBJECT_HAS_EXTENSIBLE(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__extensible:true");
		}
		if (DUK_HOBJECT_HAS_CONSTRUCTABLE(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__constructable:true");
		}
		if (DUK_HOBJECT_HAS_BOUNDFUNC(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__boundfunc:true");
		}
		if (DUK_HOBJECT_HAS_COMPFUNC(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__compfunc:true");
		}
		if (DUK_HOBJECT_HAS_NATFUNC(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__natfunc:true");
		}
		if (DUK_HOBJECT_HAS_BUFOBJ(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__bufobj:true");
		}
		if (DUK_HOBJECT_HAS_THREAD(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__thread:true");
		}
		if (DUK_HOBJECT_HAS_ARRAY_PART(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__array_part:true");
		}
		if (DUK_HOBJECT_HAS_STRICT(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__strict:true");
		}
		if (DUK_HOBJECT_HAS_NOTAIL(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__notail:true");
		}
		if (DUK_HOBJECT_HAS_NEWENV(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__newenv:true");
		}
		if (DUK_HOBJECT_HAS_NAMEBINDING(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__namebinding:true");
		}
		if (DUK_HOBJECT_HAS_CREATEARGS(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__createargs:true");
		}
		if (DUK_HOBJECT_HAS_ENVRECCLOSED(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__envrecclosed:true");
		}
		if (DUK_HOBJECT_HAS_EXOTIC_ARRAY(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__exotic_array:true");
		}
		if (DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__exotic_stringobj:true");
		}
		if (DUK_HOBJECT_HAS_EXOTIC_ARGUMENTS(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__exotic_arguments:true");
		}
		if (DUK_HOBJECT_HAS_EXOTIC_DUKFUNC(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__exotic_dukfunc:true");
		}
		if (DUK_HOBJECT_IS_BUFOBJ(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__exotic_bufobj:true");
		}
		if (DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(h)) {
			DUK__COMMA(); duk_fb_sprintf(fb, "__exotic_proxyobj:true");
		}
	}

	if (st->internal && DUK_HOBJECT_IS_ARRAY(h)) {
		duk_harray *a = (duk_harray *) h;
		DUK__COMMA(); duk_fb_sprintf(fb, "__length:%ld", (long) a->length);
		DUK__COMMA(); duk_fb_sprintf(fb, "__length_nonwritable:%ld", (long) a->length_nonwritable);
	} else if (st->internal && DUK_HOBJECT_IS_COMPFUNC(h)) {
		duk_hcompfunc *f = (duk_hcompfunc *) h;
		DUK__COMMA(); duk_fb_put_cstring(fb, "__data:");
		duk__print_hbuffer(st, (duk_hbuffer *) DUK_HCOMPFUNC_GET_DATA(NULL, f));
		DUK__COMMA(); duk_fb_put_cstring(fb, "__lexenv:"); duk__print_hobject(st, DUK_HCOMPFUNC_GET_LEXENV(NULL, f));
		DUK__COMMA(); duk_fb_put_cstring(fb, "__varenv:"); duk__print_hobject(st, DUK_HCOMPFUNC_GET_VARENV(NULL, f));
		DUK__COMMA(); duk_fb_sprintf(fb, "__nregs:%ld", (long) f->nregs);
		DUK__COMMA(); duk_fb_sprintf(fb, "__nargs:%ld", (long) f->nargs);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
		DUK__COMMA(); duk_fb_sprintf(fb, "__start_line:%ld", (long) f->start_line);
		DUK__COMMA(); duk_fb_sprintf(fb, "__end_line:%ld", (long) f->end_line);
#endif
		DUK__COMMA(); duk_fb_put_cstring(fb, "__data:");
		duk__print_hbuffer(st, (duk_hbuffer *) DUK_HCOMPFUNC_GET_DATA(NULL, f));
	} else if (st->internal && DUK_HOBJECT_IS_NATFUNC(h)) {
		duk_hnatfunc *f = (duk_hnatfunc *) h;
		DUK__COMMA(); duk_fb_sprintf(fb, "__func:");
		duk_fb_put_funcptr(fb, (duk_uint8_t *) &f->func, sizeof(f->func));
		DUK__COMMA(); duk_fb_sprintf(fb, "__nargs:%ld", (long) f->nargs);
		DUK__COMMA(); duk_fb_sprintf(fb, "__magic:%ld", (long) f->magic);
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
	} else if (st->internal && DUK_HOBJECT_IS_BUFOBJ(h)) {
		duk_hbufobj *b = (duk_hbufobj *) h;
		DUK__COMMA(); duk_fb_sprintf(fb, "__buf:");
		duk__print_hbuffer(st, (duk_hbuffer *) b->buf);
		DUK__COMMA(); duk_fb_sprintf(fb, "__buf_prop:");
		duk__print_hobject(st, (duk_hobject *) b->buf_prop);
		DUK__COMMA(); duk_fb_sprintf(fb, "__offset:%ld", (long) b->offset);
		DUK__COMMA(); duk_fb_sprintf(fb, "__length:%ld", (long) b->length);
		DUK__COMMA(); duk_fb_sprintf(fb, "__shift:%ld", (long) b->shift);
		DUK__COMMA(); duk_fb_sprintf(fb, "__elemtype:%ld", (long) b->elem_type);
#endif
	} else if (st->internal && DUK_HOBJECT_IS_THREAD(h)) {
		duk_hthread *t = (duk_hthread *) h;
		DUK__COMMA(); duk_fb_sprintf(fb, "__strict:%ld", (long) t->strict);
		DUK__COMMA(); duk_fb_sprintf(fb, "__state:%ld", (long) t->state);
		DUK__COMMA(); duk_fb_sprintf(fb, "__unused1:%ld", (long) t->unused1);
		DUK__COMMA(); duk_fb_sprintf(fb, "__unused2:%ld", (long) t->unused2);
		DUK__COMMA(); duk_fb_sprintf(fb, "__valstack_max:%ld", (long) t->valstack_max);
		DUK__COMMA(); duk_fb_sprintf(fb, "__callstack_max:%ld", (long) t->callstack_max);
		DUK__COMMA(); duk_fb_sprintf(fb, "__catchstack_max:%ld", (long) t->catchstack_max);
		DUK__COMMA(); duk_fb_sprintf(fb, "__valstack:%p", (void *) t->valstack);
		DUK__COMMA(); duk_fb_sprintf(fb, "__valstack_end:%p/%ld", (void *) t->valstack_end, (long) (t->valstack_end - t->valstack));
		DUK__COMMA(); duk_fb_sprintf(fb, "__valstack_bottom:%p/%ld", (void *) t->valstack_bottom, (long) (t->valstack_bottom - t->valstack));
		DUK__COMMA(); duk_fb_sprintf(fb, "__valstack_top:%p/%ld", (void *) t->valstack_top, (long) (t->valstack_top - t->valstack));
		DUK__COMMA(); duk_fb_sprintf(fb, "__catchstack:%p", (void *) t->catchstack);
		DUK__COMMA(); duk_fb_sprintf(fb, "__catchstack_size:%ld", (long) t->catchstack_size);
		DUK__COMMA(); duk_fb_sprintf(fb, "__catchstack_top:%ld", (long) t->catchstack_top);
		DUK__COMMA(); duk_fb_sprintf(fb, "__resumer:"); duk__print_hobject(st, (duk_hobject *) t->resumer);
		/* XXX: print built-ins array? */

	}
#if defined(DUK_USE_REFERENCE_COUNTING)
	if (st->internal) {
		DUK__COMMA(); duk_fb_sprintf(fb, "__refcount:%lu", (unsigned long) DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h));
	}
#endif
	if (st->internal) {
		DUK__COMMA(); duk_fb_sprintf(fb, "__class:%ld", (long) DUK_HOBJECT_GET_CLASS_NUMBER(h));
	}

	DUK__COMMA(); duk_fb_sprintf(fb, "__heapptr:%p", (void *) h);  /* own pointer */

	/* prototype should be last, for readability */
	if (DUK_HOBJECT_GET_PROTOTYPE(NULL, h)) {
		if (st->follow_proto) {
			DUK__COMMA(); duk_fb_put_cstring(fb, "__prototype:"); duk__print_hobject(st, DUK_HOBJECT_GET_PROTOTYPE(NULL, h));
		} else {
			DUK__COMMA(); duk_fb_sprintf(fb, "__prototype:%p", (void *) DUK_HOBJECT_GET_PROTOTYPE(NULL, h));
		}
	}

	duk_fb_put_cstring(fb, brace2);

#if defined(DUK_USE_HOBJECT_HASH_PART)
	if (st->heavy && DUK_HOBJECT_GET_HSIZE(h) > 0) {
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_LANGLE);
		for (i = 0; i < DUK_HOBJECT_GET_HSIZE(h); i++) {
			duk_uint_t h_idx = DUK_HOBJECT_H_GET_INDEX(NULL, h, i);
			if (i > 0) {
				duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_COMMA);
			}
			if (h_idx == DUK_HOBJECT_HASHIDX_UNUSED) {
				duk_fb_sprintf(fb, "u");
			} else if (h_idx == DUK_HOBJECT_HASHIDX_DELETED) {
				duk_fb_sprintf(fb, "d");
			} else {
				duk_fb_sprintf(fb, "%ld", (long) h_idx);
			}
		}
		duk_fb_put_byte(fb, (duk_uint8_t) DUK_ASC_RANGLE);
	}
#endif

 finished:
	st->depth--;
	if (pushed_loopstack) {
		st->loop_stack_index--;
		st->loop_stack[st->loop_stack_index] = NULL;
	}
}
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;
}