public VariableStack mapStackToLocal(VariableStack stack) {
		StructuredBlock[] subBlocks = getSubBlocks();
		VariableStack after;
		if (subBlocks.length == 0)
			after = stack;
		else {
			after = null;
			for (int i = 0; i < subBlocks.length; i++) {
				after = VariableStack.merge(after,
						subBlocks[i].mapStackToLocal(stack));
			}
		}
		if (jump != null) {
			/* assert(after != null) */
			jump.stackMap = after;
			return null;
		}
		return after;
	}