/// <summary>
/// Recursively analyze the definition of a function.
/// </summary>
private static void AnalyzeDefinition(QilNode nd)
{
Debug.Assert(XmlILConstructInfo.Read(nd).PushToWriterLast,
"Only need to analyze expressions which will be compiled in push mode.");
switch (nd.NodeType)
{
case QilNodeType.Invoke:
// Invoke node can either be compiled as IteratorThenWriter, or Writer.
// Since IteratorThenWriter involves caching the results of the function call
// and iterating over them, .tailcall cannot be used
if (XmlILConstructInfo.Read(nd).ConstructMethod == XmlILConstructMethod.Writer)
{
OptimizerPatterns.Write(nd).AddPattern(OptimizerPatternName.TailCall);
}
break;
case QilNodeType.Loop: {
// Recursively analyze Loop return value
QilLoop ndLoop = (QilLoop)nd;
if (ndLoop.Variable.NodeType == QilNodeType.Let || !ndLoop.Variable.Binding.XmlType.MaybeMany)
{
AnalyzeDefinition(ndLoop.Body);
}
break;
}
case QilNodeType.Sequence: {
// Recursively analyze last expression in Sequence
QilList ndSeq = (QilList)nd;
if (ndSeq.Count > 0)
{
AnalyzeDefinition(ndSeq[ndSeq.Count - 1]);
}
break;
}
case QilNodeType.Choice: {
// Recursively analyze Choice branches
QilChoice ndChoice = (QilChoice)nd;
for (int i = 0; i < ndChoice.Branches.Count; i++)
{
AnalyzeDefinition(ndChoice.Branches[i]);
}
break;
}
case QilNodeType.Conditional: {
// Recursively analyze Conditional branches
QilTernary ndCond = (QilTernary)nd;
AnalyzeDefinition(ndCond.Center);
AnalyzeDefinition(ndCond.Right);
break;
}
case QilNodeType.Nop:
AnalyzeDefinition(((QilUnary)nd).Child);
break;
}
}
/// <summary>
/// Analyze choice.
/// </summary>
protected virtual void AnalyzeChoice(QilChoice ndChoice, XmlILConstructInfo info)
{
PossibleXmlStates xstatesChoice;
int idx;
// Visit default branch; save resulting states
idx = ndChoice.Branches.Count - 1;
ndChoice.Branches[idx] = AnalyzeContent(ndChoice.Branches[idx]);
xstatesChoice = this.xstates;
// Visit all other branches
while (--idx >= 0)
{
// Restore starting states and visit the next branch
this.xstates = info.InitialStates;
ndChoice.Branches[idx] = AnalyzeContent(ndChoice.Branches[idx]);
// Choice ending states consist of combination of all branch states
if (xstatesChoice != this.xstates)
{
xstatesChoice = PossibleXmlStates.Any;
}
}
this.xstates = xstatesChoice;
}
