private static bool RequiresControlFlowUpdate(
TerminatorValue oldTerminator,
TerminatorValue newTerminator)
{
if (oldTerminator == newTerminator)
{
return(false);
}
if (oldTerminator == null || newTerminator == null)
{
return(true);
}
// Check whether the new terminator has the identical list of
// successors. In theory we could check whether both lists contain
// the same blocks without paying attention to the order; however,
// this is very unlikely and expensive to verify.
var oldSuccessors = oldTerminator.Targets;
var newSuccessors = newTerminator.Targets;
if (oldSuccessors.Length != newSuccessors.Length)
{
return(true);
}
for (int i = 0, e = oldSuccessors.Length; i < e; ++i)
{
if (oldSuccessors[i] != newSuccessors[i])
{
return(true);
}
}
return(false);
}
/// <summary>
/// Schedules control-flow updates if the successor relation has been
/// changed by setting a new terminator.
/// </summary>
public void ScheduleControlFlowUpdate(
TerminatorValue oldTerminator,
TerminatorValue newTerminator)
{
if (RequiresControlFlowUpdate(oldTerminator, newTerminator))
{
ScheduleControlFlowUpdate();
}
}
/// <summary> /// Compacts the terminator. /// </summary> /// <returns></returns> private TerminatorValue CompactTerminator() => Terminator = Terminator?.ResolveAs <TerminatorValue>();
/// <summary> /// Creates an instantiated terminator. /// </summary> /// <param name="node">The terminator to create.</param> /// <returns>The created node.</returns> protected abstract TerminatorValue CreateTerminator(TerminatorValue node);
