C++ DUK_D函数代码示例

DUK_INTERNAL duk_uint_t duk_selftest_run_tests(duk_alloc_function alloc_func,
                                               duk_realloc_function realloc_func,
                                               duk_free_function free_func,
                                               void *udata) {
	duk_uint_t error_count = 0;

	DUK_D(DUK_DPRINT("self test starting"));

	error_count += duk__selftest_types();
	error_count += duk__selftest_packed_tval();
	error_count += duk__selftest_twos_complement();
	error_count += duk__selftest_byte_order();
	error_count += duk__selftest_bswap_macros();
	error_count += duk__selftest_double_union_size();
	error_count += duk__selftest_double_aliasing();
	error_count += duk__selftest_double_zero_sign();
	error_count += duk__selftest_double_rounding();
	error_count += duk__selftest_struct_align();
	error_count += duk__selftest_64bit_arithmetic();
	error_count += duk__selftest_cast_double_to_small_uint();
	error_count += duk__selftest_cast_double_to_uint32();
	error_count += duk__selftest_alloc_funcs(alloc_func, realloc_func, free_func, udata);

	DUK_D(DUK_DPRINT("self test complete, total error count: %ld", (long) error_count));

	return error_count;
}

void duk_debug_dump_callstack(duk_hthread *thr) {
	duk_uint_fast32_t i;

	DUK_D(DUK_DPRINT("=== hthread %p callstack: %d entries ===",
	                 (void *) thr,
	                 (thr == NULL ? 0 : thr->callstack_top)));
	if (!thr) {
		return;
	}

	for (i = 0; i < thr->callstack_top; i++) {
		duk_activation *act = &thr->callstack[i];
		duk_tval *this_binding = NULL;

		this_binding = thr->valstack + act->idx_bottom - 1;
		if (this_binding < thr->valstack || this_binding >= thr->valstack_top) {
			this_binding = NULL;
		}

		DUK_D(DUK_DPRINT("  [%d] -> flags=0x%08x, func=%!O, var_env=%!iO, lex_env=%!iO, pc=%d, idx_bottom=%d, idx_retval=%d, this_binding=%!T",
		                 i,
		                 act->flags,
		                 (duk_heaphdr *) act->func,
		                 (duk_heaphdr *) act->var_env,
		                 (duk_heaphdr *) act->lex_env,
		                 act->pc,
		                 act->idx_bottom,
		                 act->idx_retval,
		                 this_binding));
	}
}

DUK_LOCAL void duk__run_object_finalizers(duk_heap *heap, duk_small_uint_t flags) {
	duk_heaphdr *curr;
	duk_heaphdr *next;
#if defined(DUK_USE_DEBUG)
	duk_size_t count = 0;
#endif
	duk_hthread *thr;

	DUK_DD(DUK_DDPRINT("duk__run_object_finalizers: %p", (void *) heap));

	thr = duk__get_temp_hthread(heap);
	DUK_ASSERT(thr != NULL);

	curr = heap->finalize_list;
	while (curr) {
		DUK_DDD(DUK_DDDPRINT("mark-and-sweep finalize: %p", (void *) curr));

		DUK_ASSERT(DUK_HEAPHDR_GET_TYPE(curr) == DUK_HTYPE_OBJECT);  /* only objects have finalizers */
		DUK_ASSERT(!DUK_HEAPHDR_HAS_REACHABLE(curr));                /* flags have been already cleared */
		DUK_ASSERT(!DUK_HEAPHDR_HAS_TEMPROOT(curr));
		DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZABLE(curr));
		DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
		DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY(curr));  /* No finalizers for ROM objects */

		if (DUK_LIKELY((flags & DUK_MS_FLAG_SKIP_FINALIZERS) == 0)) {
			/* Run the finalizer, duk_hobject_run_finalizer() sets FINALIZED.
			 * Next mark-and-sweep will collect the object unless it has
			 * become reachable (i.e. rescued).  FINALIZED prevents the
			 * finalizer from being executed again before that.
			 */
			duk_hobject_run_finalizer(thr, (duk_hobject *) curr);  /* must never longjmp */
			DUK_ASSERT(DUK_HEAPHDR_HAS_FINALIZED(curr));
		} else {
			/* Used during heap destruction: don't actually run finalizers
			 * because we're heading into forced finalization.  Instead,
			 * queue finalizable objects back to the heap_allocated list.
			 */
			DUK_D(DUK_DPRINT("skip finalizers flag set, queue object to heap_allocated without finalizing"));
			DUK_ASSERT(!DUK_HEAPHDR_HAS_FINALIZED(curr));
		}

		/* queue back to heap_allocated */
		next = DUK_HEAPHDR_GET_NEXT(heap, curr);
		DUK_HEAP_INSERT_INTO_HEAP_ALLOCATED(heap, curr);

		curr = next;
#if defined(DUK_USE_DEBUG)
		count++;
#endif
	}

	/* finalize_list will always be processed completely */
	heap->finalize_list = NULL;

#if defined(DUK_USE_DEBUG)
	DUK_D(DUK_DPRINT("mark-and-sweep finalize objects: %ld finalizers called", (long) count));
#endif
}

DUK_INTERNAL void duk_hobject_run_finalizer(duk_hthread *thr, duk_hobject *obj) {
	duk_context *ctx = (duk_context *) thr;
	duk_ret_t rc;
#if defined(DUK_USE_ASSERTIONS)
	duk_idx_t entry_top;
#endif

	DUK_DDD(DUK_DDDPRINT("running object finalizer for object: %p", (void *) obj));

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(ctx != NULL);
	DUK_ASSERT(obj != NULL);
	DUK_ASSERT_VALSTACK_SPACE(thr, 1);

#if defined(DUK_USE_ASSERTIONS)
	entry_top = duk_get_top(ctx);
#endif
	/*
	 *  Get and call the finalizer.  All of this must be wrapped
	 *  in a protected call, because even getting the finalizer
	 *  may trigger an error (getter may throw one, for instance).
	 */

	DUK_ASSERT(!DUK_HEAPHDR_HAS_READONLY((duk_heaphdr *) obj));
	if (DUK_HEAPHDR_HAS_FINALIZED((duk_heaphdr *) obj)) {
		DUK_D(DUK_DPRINT("object already finalized, avoid running finalizer twice: %!O", obj));
		return;
	}
	DUK_HEAPHDR_SET_FINALIZED((duk_heaphdr *) obj);  /* ensure never re-entered until rescue cycle complete */
	if (DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(obj)) {
		/* This shouldn't happen; call sites should avoid looking up
		 * _Finalizer "through" a Proxy, but ignore if we come here
		 * with a Proxy to avoid finalizer re-entry.
		 */
		DUK_D(DUK_DPRINT("object is a proxy, skip finalizer call"));
		return;
	}

	/* XXX: use a NULL error handler for the finalizer call? */

	DUK_DDD(DUK_DDDPRINT("-> finalizer found, calling wrapped finalize helper"));
	duk_push_hobject(ctx, obj);  /* this also increases refcount by one */
	rc = duk_safe_call(ctx, duk__finalize_helper, NULL /*udata*/, 0 /*nargs*/, 1 /*nrets*/);  /* -> [... obj retval/error] */
	DUK_ASSERT_TOP(ctx, entry_top + 2);  /* duk_safe_call discipline */

	if (rc != DUK_EXEC_SUCCESS) {
		/* Note: we ask for one return value from duk_safe_call to get this
		 * error debugging here.
		 */
		DUK_D(DUK_DPRINT("wrapped finalizer call failed for object %p (ignored); error: %!T",
		                 (void *) obj, (duk_tval *) duk_get_tval(ctx, -1)));
	}
	duk_pop_2(ctx);  /* -> [...] */

	DUK_ASSERT_TOP(ctx, entry_top);
}

DUK_INTERNAL void duk_err_setup_heap_ljstate(duk_hthread *thr, duk_small_int_t lj_type) {
	duk_tval tv_tmp;

#if defined(DUK_USE_DEBUGGER_SUPPORT)

	/* If something is thrown with the debugger attached and nobody will
	 * catch it, execution is paused before the longjmp, turning over
	 * control to the debug client. This allows local state to be examined
	 * before the stack is unwound.
	 */

	/* TODO: Allow customizing the pause and notify behavior */

	if (DUK_HEAP_IS_DEBUGGER_ATTACHED(thr->heap) && lj_type == DUK_LJ_TYPE_THROW) {
		duk_context *ctx = (duk_context *) thr;
		duk_bool_t fatal;
		duk_hobject *h_obj;

		/* Don't intercept a DoubleError, we may have caused the initial double
		 * fault and attempting to intercept it will cause us to be called
		 * recursively and exhaust the C stack.
		 */
		h_obj = duk_get_hobject(ctx, -1);
		if (h_obj == thr->builtins[DUK_BIDX_DOUBLE_ERROR]) {
			DUK_D(DUK_DPRINT("built-in DoubleError instance thrown, not intercepting"));
			goto skip_throw_intercept;
		}

		DUK_D(DUK_DPRINT("throw with debugger attached, report to client"));

		fatal = !duk__have_active_catcher(thr);

		/* Report it to the debug client */
		duk_debug_send_throw(thr, fatal);

		if (fatal) {
			DUK_D(DUK_DPRINT("throw will be fatal, halt before longjmp"));
			duk_debug_halt_execution(thr, 1 /*use_prev_pc*/);
		}
	}

skip_throw_intercept:

#endif

	thr->heap->lj.type = lj_type;

	DUK_ASSERT(thr->valstack_top > thr->valstack);
	DUK_TVAL_SET_TVAL(&tv_tmp, &thr->heap->lj.value1);
	DUK_TVAL_SET_TVAL(&thr->heap->lj.value1, thr->valstack_top - 1);
	DUK_TVAL_INCREF(thr, &thr->heap->lj.value1);
	DUK_TVAL_DECREF(thr, &tv_tmp);

	duk_pop((duk_context *) thr);
}

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
		}
	}
}

//.........这里部分代码省略.........

	e = heap->strtable + slotidx;
	if (e->listlen == 0) {
		if (e->u.str != NULL &&
	           DUK_HSTRING_GET_BYTELEN(e->u.str) == blen &&
	           DUK_MEMCMP((const void *) str, (const void *) DUK_HSTRING_GET_DATA(e->u.str), (size_t) blen) == 0) {
			return e->u.str;
		}
	} else {
		DUK_ASSERT(e->u.strlist != NULL);
		lst = e->u.strlist;
		for (i = 0, n = e->listlen; i < n; i++) {
			if (lst[i] != NULL &&
		           DUK_HSTRING_GET_BYTELEN(lst[i]) == blen &&
		           DUK_MEMCMP((const void *) str, (const void *) DUK_HSTRING_GET_DATA(lst[i]), (size_t) blen) == 0) {
				return lst[i];
			}
		}
	}

	return NULL;
}
#endif  /* DUK_USE_HEAPPTR16 */

#if defined(DUK_USE_HEAPPTR16)
DUK_LOCAL void duk__remove_matching_hstring_chain(duk_heap *heap, duk_hstring *h) {
	duk_small_uint_t slotidx;
	duk_strtab_entry *e;
	duk_uint16_t *lst;
	duk_size_t i, n;
	duk_uint16_t h16;
	duk_uint16_t null16 = heap->heapptr_null16;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(h != NULL);

	slotidx = DUK_HSTRING_GET_HASH(h) % DUK_STRTAB_CHAIN_SIZE;
	DUK_ASSERT(slotidx < DUK_STRTAB_CHAIN_SIZE);

	DUK_ASSERT(h != NULL);
	h16 = DUK_USE_HEAPPTR_ENC16(heap->heap_udata, (void *) h);

	e = heap->strtable + slotidx;
	if (e->listlen == 0) {
		if (e->u.str16 == h16) {
			e->u.str16 = null16;
			return;
		}
	} else {
		DUK_ASSERT(e->u.strlist16 != null16);
		lst = (duk_uint16_t *) DUK_USE_HEAPPTR_DEC16(heap->heap_udata, e->u.strlist16);
		DUK_ASSERT(lst != NULL);
		for (i = 0, n = e->listlen; i < n; i++) {
			if (lst[i] == h16) {
				lst[i] = null16;
				return;
			}
		}
	}

	DUK_D(DUK_DPRINT("failed to find string that should be in stringtable"));
	DUK_UNREACHABLE();
	return;
}
#else  /* DUK_USE_HEAPPTR16 */
DUK_LOCAL void duk__remove_matching_hstring_chain(duk_heap *heap, duk_hstring *h) {
	duk_small_uint_t slotidx;
	duk_strtab_entry *e;
	duk_hstring **lst;
	duk_size_t i, n;

	DUK_ASSERT(heap != NULL);
	DUK_ASSERT(h != NULL);

	slotidx = DUK_HSTRING_GET_HASH(h) % DUK_STRTAB_CHAIN_SIZE;
	DUK_ASSERT(slotidx < DUK_STRTAB_CHAIN_SIZE);

	e = heap->strtable + slotidx;
	if (e->listlen == 0) {
		DUK_ASSERT(h != NULL);
		if (e->u.str == h) {
			e->u.str = NULL;
			return;
		}
	} else {
		DUK_ASSERT(e->u.strlist != NULL);
		lst = e->u.strlist;
		for (i = 0, n = e->listlen; i < n; i++) {
			DUK_ASSERT(h != NULL);
			if (lst[i] == h) {
				lst[i] = NULL;
				return;
			}
		}
	}

	DUK_D(DUK_DPRINT("failed to find string that should be in stringtable"));
	DUK_UNREACHABLE();
	return;
}

DUK_LOCAL void duk__compact_objects(duk_heap *heap) {
	/* XXX: which lists should participate?  to be finalized? */
#if defined(DUK_USE_DEBUG)
	duk_size_t count_check = 0;
	duk_size_t count_compact = 0;
	duk_size_t count_bytes_saved = 0;
#endif
	duk_hthread *thr;

	DUK_DD(DUK_DDPRINT("duk__compact_objects: %p", (void *) heap));

	thr = duk__get_temp_hthread(heap);
	DUK_ASSERT(thr != NULL);

#if defined(DUK_USE_DEBUG)
	duk__compact_object_list(heap, thr, heap->heap_allocated, &count_check, &count_compact, &count_bytes_saved);
	duk__compact_object_list(heap, thr, heap->finalize_list, &count_check, &count_compact, &count_bytes_saved);
#if defined(DUK_USE_REFERENCE_COUNTING)
	duk__compact_object_list(heap, thr, heap->refzero_list, &count_check, &count_compact, &count_bytes_saved);
#endif
#else
	duk__compact_object_list(heap, thr, heap->heap_allocated);
	duk__compact_object_list(heap, thr, heap->finalize_list);
#if defined(DUK_USE_REFERENCE_COUNTING)
	duk__compact_object_list(heap, thr, heap->refzero_list);
#endif
#endif

#if defined(DUK_USE_DEBUG)
	DUK_D(DUK_DPRINT("mark-and-sweep compact objects: %ld checked, %ld compaction attempts, %ld bytes saved by compaction",
	                 (long) count_check, (long) count_compact, (long) count_bytes_saved));
#endif
}

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);
	}
}

static int duk__init_heap_thread(duk_heap *heap) {
	duk_hthread *thr;
	
	DUK_DD(DUK_DDPRINT("heap init: alloc heap thread"));
	thr = duk_hthread_alloc(heap,
	                        DUK_HOBJECT_FLAG_EXTENSIBLE |
	                        DUK_HOBJECT_FLAG_THREAD |
	                        DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_THREAD));
	if (!thr) {
		DUK_D(DUK_DPRINT("failed to alloc heap_thread"));
		return 0;
	}
	thr->state = DUK_HTHREAD_STATE_INACTIVE;
	thr->strs = heap->strs;

	heap->heap_thread = thr;
	DUK_HTHREAD_INCREF(thr, thr);  /* Note: first argument not really used */

	/* 'thr' is now reachable */

	if (!duk_hthread_init_stacks(heap, thr)) {
		return 0;
	}

	/* FIXME: this may now fail, and is not handled correctly */
	duk_hthread_create_builtin_objects(thr);

	/* default prototype (Note: 'thr' must be reachable) */
	DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, (duk_hobject *) thr, thr->builtins[DUK_BIDX_THREAD_PROTOTYPE]);

	return 1;
}

void duk_hthread_callstack_shrink_check(duk_hthread *thr) {
	duk_size_t new_size;
	duk_activation *p;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT_DISABLE(thr->callstack_top >= 0);  /* avoid warning (unsigned) */
	DUK_ASSERT(thr->callstack_size >= thr->callstack_top);

	if (thr->callstack_size - thr->callstack_top < DUK_CALLSTACK_SHRINK_THRESHOLD) {
		return;
	}

	new_size = thr->callstack_top + DUK_CALLSTACK_SHRINK_SPARE;
	DUK_ASSERT(new_size >= thr->callstack_top);

	DUK_DD(DUK_DDPRINT("shrinking callstack %d -> %d", thr->callstack_size, new_size));

	/*
	 *  Note: must use indirect variant of DUK_REALLOC() because underlying
	 *  pointer may be changed by mark-and-sweep.
	 */

	/* shrink failure is not fatal */
	p = (duk_activation *) DUK_REALLOC_INDIRECT(thr->heap, duk_hthread_get_callstack_ptr, (void *) thr, sizeof(duk_activation) * new_size);
	if (p) {
		thr->callstack = p;
		thr->callstack_size = new_size;
	} else {
		DUK_D(DUK_DPRINT("callstack shrink failed, ignoring"));
	}

	/* note: any entries above the callstack top are garbage and not zeroed */
}

DUK_LOCAL duk_uint_t duk__selftest_bswap_macros(void) {
	duk_uint_t error_count = 0;
	duk_uint32_t x32;
	duk_uint16_t x16;
	duk_double_union du;
	duk_double_t du_diff;

	x16 = 0xbeefUL;
	x16 = DUK_BSWAP16(x16);
	if (x16 != (duk_uint16_t) 0xefbeUL) {
		DUK__FAILED("DUK_BSWAP16");
	}

	x32 = 0xdeadbeefUL;
	x32 = DUK_BSWAP32(x32);
	if (x32 != (duk_uint32_t) 0xefbeaddeUL) {
		DUK__FAILED("DUK_BSWAP32");
	}

	/* >>> struct.unpack('>d', '4000112233445566'.decode('hex'))
	 * (2.008366013071895,)
	 */

	du.uc[0] = 0x40; du.uc[1] = 0x00; du.uc[2] = 0x11; du.uc[3] = 0x22;
	du.uc[4] = 0x33; du.uc[5] = 0x44; du.uc[6] = 0x55; du.uc[7] = 0x66;
	DUK_DBLUNION_DOUBLE_NTOH(&du);
	du_diff = du.d - 2.008366013071895;
#if 0
	DUK_D(DUK_DPRINT("du_diff: %lg\n", (double) du_diff));
#endif
	if (du_diff > 1e-15) {
		/* Allow very small lenience because some compilers won't parse
		 * exact IEEE double constants (happened in matrix testing with
		 * Linux gcc-4.8 -m32 at least).
		 */
#if 0
		DUK_D(DUK_DPRINT("Result of DUK_DBLUNION_DOUBLE_NTOH: %02x %02x %02x %02x %02x %02x %02x %02x\n",
		            (unsigned int) du.uc[0], (unsigned int) du.uc[1],
		            (unsigned int) du.uc[2], (unsigned int) du.uc[3],
		            (unsigned int) du.uc[4], (unsigned int) du.uc[5],
		            (unsigned int) du.uc[6], (unsigned int) du.uc[7]));
#endif
		DUK__FAILED("DUK_DBLUNION_DOUBLE_NTOH");
	}

	return error_count;
}

/* recursion tracking happens here only */
DUK_LOCAL void duk__mark_heaphdr(duk_heap *heap, duk_heaphdr *h) {
	DUK_DDD(DUK_DDDPRINT("duk__mark_heaphdr %p, type %ld",
	                     (void *) h,
	                     (h != NULL ? (long) DUK_HEAPHDR_GET_TYPE(h) : (long) -1)));
	if (!h) {
		return;
	}
#if defined(DUK_USE_ROM_OBJECTS)
	if (DUK_HEAPHDR_HAS_READONLY(h)) {
		DUK_DDD(DUK_DDDPRINT("readonly object %p, skip", (void *) h));
		return;
	}
#endif
	if (DUK_HEAPHDR_HAS_REACHABLE(h)) {
		DUK_DDD(DUK_DDDPRINT("already marked reachable, skip"));
		return;
	}
	DUK_HEAPHDR_SET_REACHABLE(h);

	if (heap->mark_and_sweep_recursion_depth >= DUK_USE_MARK_AND_SWEEP_RECLIMIT) {
		/* log this with a normal debug level because this should be relatively rare */
		DUK_D(DUK_DPRINT("mark-and-sweep recursion limit reached, marking as temproot: %p", (void *) h));
		DUK_HEAP_SET_MARKANDSWEEP_RECLIMIT_REACHED(heap);
		DUK_HEAPHDR_SET_TEMPROOT(h);
		return;
	}

	heap->mark_and_sweep_recursion_depth++;

	switch (DUK_HEAPHDR_GET_TYPE(h)) {
	case DUK_HTYPE_STRING:
		duk__mark_hstring(heap, (duk_hstring *) h);
		break;
	case DUK_HTYPE_OBJECT:
		duk__mark_hobject(heap, (duk_hobject *) h);
		break;
	case DUK_HTYPE_BUFFER:
		/* nothing to mark */
		break;
	default:
		DUK_D(DUK_DPRINT("attempt to mark heaphdr %p with invalid htype %ld", (void *) h, (long) DUK_HEAPHDR_GET_TYPE(h)));
		DUK_UNREACHABLE();
	}

	heap->mark_and_sweep_recursion_depth--;
}

static void duk__sweep_stringtable(duk_heap *heap, duk_size_t *out_count_keep) {
	duk_hstring *h;
	duk_uint_fast32_t i;
#ifdef DUK_USE_DEBUG
	duk_size_t count_free = 0;
#endif
	duk_size_t count_keep = 0;

	DUK_DD(DUK_DDPRINT("duk__sweep_stringtable: %p", (void *) heap));

	for (i = 0; i < heap->st_size; i++) {
		h = heap->st[i];
		if (h == NULL || h == DUK_STRTAB_DELETED_MARKER(heap)) {
			continue;
		} else if (DUK_HEAPHDR_HAS_REACHABLE((duk_heaphdr *) h)) {
			DUK_HEAPHDR_CLEAR_REACHABLE((duk_heaphdr *) h);
			count_keep++;
			continue;
		}

#ifdef DUK_USE_DEBUG
		count_free++;
#endif

#if defined(DUK_USE_REFERENCE_COUNTING)
		/* Non-zero refcounts should not happen for unreachable strings,
		 * because we refcount finalize all unreachable objects which
		 * should have decreased unreachable string refcounts to zero
		 * (even for cycles).
		 */
		DUK_ASSERT(DUK_HEAPHDR_GET_REFCOUNT((duk_heaphdr *) h) == 0);
#endif

		DUK_DDD(DUK_DDDPRINT("sweep string, not reachable: %p", (void *) h));

		/* deal with weak references first */
		duk_heap_strcache_string_remove(heap, (duk_hstring *) h);

		/* remove the string (mark DELETED), could also call
		 * duk_heap_string_remove() but that would be slow and
		 * pointless because we already know the slot.
		 */
		heap->st[i] = DUK_STRTAB_DELETED_MARKER(heap);

		/* then free */
#if 1
		DUK_FREE(heap, (duk_heaphdr *) h);  /* no inner refs/allocs, just free directly */
#else
		duk_heap_free_heaphdr_raw(heap, (duk_heaphdr *) h);  /* this would be OK but unnecessary */
#endif
	}

#ifdef DUK_USE_DEBUG
	DUK_D(DUK_DPRINT("mark-and-sweep sweep stringtable: %d freed, %d kept",
	                 (int) count_free, (int) count_keep));
#endif
	*out_count_keep = count_keep;
}

static void duk__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
}