Beispiel #1
0
DUK_LOCAL duk_uint8_t *duk__dump_varmap(duk_hthread *thr, duk_uint8_t *p, duk_bufwriter_ctx *bw_ctx, duk_hobject *func) {
	duk_tval *tv;

	tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, (duk_hobject *) func, DUK_HTHREAD_STRING_INT_VARMAP(thr));
	if (tv != NULL && DUK_TVAL_IS_OBJECT(tv)) {
		duk_hobject *h;
		duk_uint_fast32_t i;

		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);

		/* We know _Varmap only has own properties so walk property
		 * table directly.  We also know _Varmap is dense and all
		 * values are numbers; assert for these.  GC and finalizers
		 * shouldn't affect _Varmap so side effects should be fine.
		 */
		for (i = 0; i < (duk_uint_fast32_t) DUK_HOBJECT_GET_ENEXT(h); i++) {
			duk_hstring *key;
			duk_tval *tv_val;
			duk_uint32_t val;

			key = DUK_HOBJECT_E_GET_KEY(thr->heap, h, i);
			DUK_ASSERT(key != NULL);  /* _Varmap is dense */
			DUK_ASSERT(!DUK_HOBJECT_E_SLOT_IS_ACCESSOR(thr->heap, h, i));
			tv_val = DUK_HOBJECT_E_GET_VALUE_TVAL_PTR(thr->heap, h, i);
			DUK_ASSERT(tv_val != NULL);
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_val));  /* known to be number; in fact an integer */
#if defined(DUK_USE_FASTINT)
			DUK_ASSERT(DUK_TVAL_IS_FASTINT(tv_val));
			DUK_ASSERT(DUK_TVAL_GET_FASTINT(tv_val) == (duk_int64_t) DUK_TVAL_GET_FASTINT_U32(tv_val));  /* known to be 32-bit */
			val = DUK_TVAL_GET_FASTINT_U32(tv_val);
#else
			val = (duk_uint32_t) DUK_TVAL_GET_NUMBER(tv_val);
#endif

			DUK_ASSERT(DUK_HSTRING_MAX_BYTELEN <= 0x7fffffffUL);  /* ensures no overflow */
			p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4 + DUK_HSTRING_GET_BYTELEN(key) + 4, p);
			p = duk__dump_hstring_raw(p, key);
			DUK_RAW_WRITE_U32_BE(p, val);
		}
	}
	p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4, p);
	DUK_RAW_WRITE_U32_BE(p, 0);  /* end of _Varmap */
	return p;
}
Beispiel #2
0
void duk_hthread_callstack_unwind(duk_hthread *thr, int new_top) {
	int idx;  /* FIXME: typing of idx and new_top */

	DUK_DDDPRINT("unwind callstack top of thread %p from %d to %d",
	             (void *) thr,
	             (thr != NULL ? (int) thr->callstack_top : (int) -1),
	             (int) new_top);

	DUK_ASSERT(thr);
	DUK_ASSERT(thr->heap);
	DUK_ASSERT(new_top >= 0);
	DUK_ASSERT((duk_size_t) new_top <= thr->callstack_top);  /* cannot grow */

	/*
	 *  The loop below must avoid issues with potential callstack
	 *  reallocations.  A resize (and other side effects) may happen
	 *  e.g. due to finalizer/errhandler calls caused by a refzero or
	 *  mark-and-sweep.  Arbitrary finalizers may run, because when
	 *  an environment record is refzero'd, it may refer to arbitrary
	 *  values which also become refzero'd.
	 *
	 *  So, the pointer 'p' is re-looked-up below whenever a side effect
	 *  might have changed it.
	 */

	idx = thr->callstack_top;
	while (idx > new_top) {
		duk_activation *p;
#ifdef DUK_USE_REFERENCE_COUNTING
		duk_hobject *tmp;
#endif

		idx--;
		DUK_ASSERT(idx >= 0);
		DUK_ASSERT((duk_size_t) idx < thr->callstack_size);  /* true, despite side effect resizes */

		p = &thr->callstack[idx];
		DUK_ASSERT(p->func != NULL);

#ifdef DUK_USE_FUNC_NONSTD_CALLER_PROPERTY
		/*
		 *  Restore 'caller' property for non-strict callee functions.
		 */

		if (!DUK_HOBJECT_HAS_STRICT(p->func)) {
			duk_tval *tv_caller;
			duk_tval tv_tmp;
			duk_hobject *h_tmp;

			tv_caller = duk_hobject_find_existing_entry_tval_ptr(p->func, DUK_HTHREAD_STRING_CALLER(thr));

			/* The p->prev_caller should only be set if the entry for 'caller'
			 * exists (as it is only set in that case, and the property is not
			 * configurable), but handle all the cases anyway.
			 */

			if (tv_caller) {
				DUK_TVAL_SET_TVAL(&tv_tmp, tv_caller);
				if (p->prev_caller) {
					/* Just transfer the refcount from p->prev_caller to tv_caller,
					 * so no need for a refcount update.  This is the expected case.
					 */
					DUK_TVAL_SET_OBJECT(tv_caller, p->prev_caller);
					p->prev_caller = NULL;
				} else {
					DUK_TVAL_SET_NULL(tv_caller);   /* no incref needed */
					DUK_ASSERT(p->prev_caller == NULL);
				}
				DUK_TVAL_DECREF(thr, &tv_tmp);  /* side effects */
			} else {
				h_tmp = p->prev_caller;
				if (h_tmp) {
					p->prev_caller = NULL;
					DUK_HOBJECT_DECREF(thr, h_tmp);  /* side effects */
				}
			}
			p = &thr->callstack[idx];  /* avoid side effects */
			DUK_ASSERT(p->prev_caller == NULL);
		}
#endif

		/*
		 *  Close environment record(s) if they exist.
		 *
		 *  Only variable environments are closed.  If lex_env != var_env, it
		 *  cannot currently contain any register bound declarations.
		 *
		 *  Only environments created for a NEWENV function are closed.  If an
		 *  environment is created for e.g. an eval call, it must not be closed.
		 */

		if (!DUK_HOBJECT_HAS_NEWENV(p->func)) {
			DUK_DDDPRINT("skip closing environments, envs not owned by this activation");
			goto skip_env_close;
		}

		DUK_ASSERT(p->lex_env == p->var_env);
		if (p->var_env != NULL) {
			DUK_DDDPRINT("closing var_env record %p -> %!O",
			             (void *) p->var_env, (duk_heaphdr *) p->var_env);
			duk_js_close_environment_record(thr, p->var_env, p->func, p->idx_bottom);
			p = &thr->callstack[idx];  /* avoid side effect issues */
		}

#if 0
		if (p->lex_env != NULL) {
			if (p->lex_env == p->var_env) {
				/* common case, already closed, so skip */
				DUK_DDPRINT("lex_env and var_env are the same and lex_env "
				            "already closed -> skip closing lex_env");
				;
			} else {
				DUK_DDPRINT("closing lex_env record %p -> %!O",
				            (void *) p->lex_env, (duk_heaphdr *) p->lex_env);
				duk_js_close_environment_record(thr, p->lex_env, p->func, p->idx_bottom);
				p = &thr->callstack[idx];  /* avoid side effect issues */
			}
		}
#endif

		DUK_ASSERT((p->lex_env == NULL) ||
		           ((duk_hobject_find_existing_entry_tval_ptr(p->lex_env, DUK_HTHREAD_STRING_INT_CALLEE(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(p->lex_env, DUK_HTHREAD_STRING_INT_VARMAP(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(p->lex_env, DUK_HTHREAD_STRING_INT_THREAD(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(p->lex_env, DUK_HTHREAD_STRING_INT_REGBASE(thr)) == NULL)));

		DUK_ASSERT((p->var_env == NULL) ||
		           ((duk_hobject_find_existing_entry_tval_ptr(p->var_env, DUK_HTHREAD_STRING_INT_CALLEE(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(p->var_env, DUK_HTHREAD_STRING_INT_VARMAP(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(p->var_env, DUK_HTHREAD_STRING_INT_THREAD(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(p->var_env, DUK_HTHREAD_STRING_INT_REGBASE(thr)) == NULL)));

	 skip_env_close:

		/*
		 *  Update preventcount
		 */

		if (p->flags & DUK_ACT_FLAG_PREVENT_YIELD) {
			DUK_ASSERT(thr->callstack_preventcount >= 1);
			thr->callstack_preventcount--;
		}

		/*
		 *  Reference count updates
		 *
		 *  Note: careful manipulation of refcounts.  The top is
		 *  not updated yet, so all the activations are reachable
		 *  for mark-and-sweep (which may be triggered by decref).
		 *  However, the pointers are NULL so this is not an issue.
		 */

#ifdef DUK_USE_REFERENCE_COUNTING
		tmp = p->var_env;
#endif
		p->var_env = NULL;
#ifdef DUK_USE_REFERENCE_COUNTING
		DUK_HOBJECT_DECREF(thr, tmp);
		p = &thr->callstack[idx];  /* avoid side effect issues */
#endif

#ifdef DUK_USE_REFERENCE_COUNTING
		tmp = p->lex_env;
#endif
		p->lex_env = NULL;
#ifdef DUK_USE_REFERENCE_COUNTING
		DUK_HOBJECT_DECREF(thr, tmp);
		p = &thr->callstack[idx];  /* avoid side effect issues */
#endif

		/* Note: this may cause a corner case situation where a finalizer
		 * may see a currently reachable activation whose 'func' is NULL.
		 */
#ifdef DUK_USE_REFERENCE_COUNTING
		tmp = p->func;
#endif
		p->func = NULL;
#ifdef DUK_USE_REFERENCE_COUNTING
		DUK_HOBJECT_DECREF(thr, tmp);
		p = &thr->callstack[idx];  /* avoid side effect issues */
#endif
	}

	thr->callstack_top = new_top;

	/*
	 *  We could clear the book-keeping variables for the topmost activation,
	 *  but don't do so now.
	 */
#if 0
	if (thr->callstack_top > 0) {
		duk_activation *p = thr->callstack + thr->callstack_top - 1;
		p->idx_retval = -1;
	}
#endif

	/* Note: any entries above the callstack top are garbage and not zeroed.
	 * Also topmost activation idx_retval is garbage and not zeroed.
	 */
}
Beispiel #3
0
DUK_INTERNAL void duk_hthread_callstack_unwind(duk_hthread *thr, duk_size_t new_top) {
	duk_size_t idx;

	DUK_DDD(DUK_DDDPRINT("unwind callstack top of thread %p from %ld to %ld",
	                     (void *) thr,
	                     (thr != NULL ? (long) thr->callstack_top : (long) -1),
	                     (long) new_top));

	DUK_ASSERT(thr);
	DUK_ASSERT(thr->heap);
	DUK_ASSERT_DISABLE(new_top >= 0);  /* unsigned */
	DUK_ASSERT((duk_size_t) new_top <= thr->callstack_top);  /* cannot grow */

	/*
	 *  The loop below must avoid issues with potential callstack
	 *  reallocations.  A resize (and other side effects) may happen
	 *  e.g. due to finalizer/errhandler calls caused by a refzero or
	 *  mark-and-sweep.  Arbitrary finalizers may run, because when
	 *  an environment record is refzero'd, it may refer to arbitrary
	 *  values which also become refzero'd.
	 *
	 *  So, the pointer 'p' is re-looked-up below whenever a side effect
	 *  might have changed it.
	 */

	idx = thr->callstack_top;
	while (idx > new_top) {
		duk_activation *act;
		duk_hobject *func;
#ifdef DUK_USE_REFERENCE_COUNTING
		duk_hobject *tmp;
#endif
#ifdef DUK_USE_DEBUGGER_SUPPORT
		duk_heap *heap;
#endif

		idx--;
		DUK_ASSERT_DISABLE(idx >= 0);  /* unsigned */
		DUK_ASSERT((duk_size_t) idx < thr->callstack_size);  /* true, despite side effect resizes */

		act = thr->callstack + idx;
		/* With lightfuncs, act 'func' may be NULL */

#ifdef DUK_USE_NONSTD_FUNC_CALLER_PROPERTY
		/*
		 *  Restore 'caller' property for non-strict callee functions.
		 */

		func = DUK_ACT_GET_FUNC(act);
		if (func != NULL && !DUK_HOBJECT_HAS_STRICT(func)) {
			duk_tval *tv_caller;
			duk_tval tv_tmp;
			duk_hobject *h_tmp;

			tv_caller = duk_hobject_find_existing_entry_tval_ptr(thr->heap, func, DUK_HTHREAD_STRING_CALLER(thr));

			/* The act->prev_caller should only be set if the entry for 'caller'
			 * exists (as it is only set in that case, and the property is not
			 * configurable), but handle all the cases anyway.
			 */

			if (tv_caller) {
				DUK_TVAL_SET_TVAL(&tv_tmp, tv_caller);
				if (act->prev_caller) {
					/* Just transfer the refcount from act->prev_caller to tv_caller,
					 * so no need for a refcount update.  This is the expected case.
					 */
					DUK_TVAL_SET_OBJECT(tv_caller, act->prev_caller);
					act->prev_caller = NULL;
				} else {
					DUK_TVAL_SET_NULL(tv_caller);   /* no incref needed */
					DUK_ASSERT(act->prev_caller == NULL);
				}
				DUK_TVAL_DECREF(thr, &tv_tmp);  /* side effects */
			} else {
				h_tmp = act->prev_caller;
				if (h_tmp) {
					act->prev_caller = NULL;
					DUK_HOBJECT_DECREF(thr, h_tmp);  /* side effects */
				}
			}
			act = thr->callstack + idx;  /* avoid side effects */
			DUK_ASSERT(act->prev_caller == NULL);
		}
#endif

		/*
		 *  Unwind debugger state.  If we unwind while stepping
		 *  (either step over or step into), pause execution.
		 */

#if defined(DUK_USE_DEBUGGER_SUPPORT)
		heap = thr->heap;
		if (heap->dbg_step_thread == thr &&
		    heap->dbg_step_csindex == idx) {
			/* Pause for all step types: step into, step over, step out.
			 * This is the only place explicitly handling a step out.
			 */
			DUK_HEAP_SET_PAUSED(heap);
			DUK_ASSERT(heap->dbg_step_thread == NULL);
		}
#endif

		/*
		 *  Close environment record(s) if they exist.
		 *
		 *  Only variable environments are closed.  If lex_env != var_env, it
		 *  cannot currently contain any register bound declarations.
		 *
		 *  Only environments created for a NEWENV function are closed.  If an
		 *  environment is created for e.g. an eval call, it must not be closed.
		 */

		func = DUK_ACT_GET_FUNC(act);
		if (func != NULL && !DUK_HOBJECT_HAS_NEWENV(func)) {
			DUK_DDD(DUK_DDDPRINT("skip closing environments, envs not owned by this activation"));
			goto skip_env_close;
		}
		/* func is NULL for lightfunc */

		DUK_ASSERT(act->lex_env == act->var_env);
		if (act->var_env != NULL) {
			DUK_DDD(DUK_DDDPRINT("closing var_env record %p -> %!O",
			                     (void *) act->var_env, (duk_heaphdr *) act->var_env));
			duk_js_close_environment_record(thr, act->var_env, func, act->idx_bottom);
			act = thr->callstack + idx;  /* avoid side effect issues */
		}

#if 0
		if (act->lex_env != NULL) {
			if (act->lex_env == act->var_env) {
				/* common case, already closed, so skip */
				DUK_DD(DUK_DDPRINT("lex_env and var_env are the same and lex_env "
				                   "already closed -> skip closing lex_env"));
				;
			} else {
				DUK_DD(DUK_DDPRINT("closing lex_env record %p -> %!O",
				                   (void *) act->lex_env, (duk_heaphdr *) act->lex_env));
				duk_js_close_environment_record(thr, act->lex_env, DUK_ACT_GET_FUNC(act), act->idx_bottom);
				act = thr->callstack + idx;  /* avoid side effect issues */
			}
		}
#endif

		DUK_ASSERT((act->lex_env == NULL) ||
		           ((duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->lex_env, DUK_HTHREAD_STRING_INT_CALLEE(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->lex_env, DUK_HTHREAD_STRING_INT_VARMAP(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->lex_env, DUK_HTHREAD_STRING_INT_THREAD(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->lex_env, DUK_HTHREAD_STRING_INT_REGBASE(thr)) == NULL)));

		DUK_ASSERT((act->var_env == NULL) ||
		           ((duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->var_env, DUK_HTHREAD_STRING_INT_CALLEE(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->var_env, DUK_HTHREAD_STRING_INT_VARMAP(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->var_env, DUK_HTHREAD_STRING_INT_THREAD(thr)) == NULL) &&
		            (duk_hobject_find_existing_entry_tval_ptr(thr->heap, act->var_env, DUK_HTHREAD_STRING_INT_REGBASE(thr)) == NULL)));

	 skip_env_close:

		/*
		 *  Update preventcount
		 */

		if (act->flags & DUK_ACT_FLAG_PREVENT_YIELD) {
			DUK_ASSERT(thr->callstack_preventcount >= 1);
			thr->callstack_preventcount--;
		}

		/*
		 *  Reference count updates
		 *
		 *  Note: careful manipulation of refcounts.  The top is
		 *  not updated yet, so all the activations are reachable
		 *  for mark-and-sweep (which may be triggered by decref).
		 *  However, the pointers are NULL so this is not an issue.
		 */

#ifdef DUK_USE_REFERENCE_COUNTING
		tmp = act->var_env;
#endif
		act->var_env = NULL;
#ifdef DUK_USE_REFERENCE_COUNTING
		DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp);
		act = thr->callstack + idx;  /* avoid side effect issues */
#endif

#ifdef DUK_USE_REFERENCE_COUNTING
		tmp = act->lex_env;
#endif
		act->lex_env = NULL;
#ifdef DUK_USE_REFERENCE_COUNTING
		DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp);
		act = thr->callstack + idx;  /* avoid side effect issues */
#endif

		/* Note: this may cause a corner case situation where a finalizer
		 * may see a currently reachable activation whose 'func' is NULL.
		 */
#ifdef DUK_USE_REFERENCE_COUNTING
		tmp = DUK_ACT_GET_FUNC(act);
#endif
		act->func = NULL;
#ifdef DUK_USE_REFERENCE_COUNTING
		DUK_HOBJECT_DECREF_ALLOWNULL(thr, tmp);
		act = thr->callstack + idx;  /* avoid side effect issues */
		DUK_UNREF(act);
#endif
	}

	thr->callstack_top = new_top;

	/*
	 *  We could clear the book-keeping variables for the topmost activation,
	 *  but don't do so now.
	 */
#if 0
	if (thr->callstack_top > 0) {
		duk_activation *act = thr->callstack + thr->callstack_top - 1;
		act->idx_retval = 0;
	}
#endif

	/* Note: any entries above the callstack top are garbage and not zeroed.
	 * Also topmost activation idx_retval is garbage (not zeroed), and must
	 * be ignored.
	 */
}