|
public static Read ( QilNode nd ) : |
||
| nd | QilNode | |
| return | ||
/// <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>
/// Perform tail-call analysis on the functions in the specified QilExpression.
/// </summary>
public static void Analyze(QilExpression qil)
{
foreach (QilFunction ndFunc in qil.FunctionList)
{
// Only analyze functions which are pushed to the writer, since otherwise code
// is generated after the call instruction in order to process cached results
if (XmlILConstructInfo.Read(ndFunc).ConstructMethod == XmlILConstructMethod.Writer)
{
AnalyzeDefinition(ndFunc.Definition);
}
}
}