public override BoundNode VisitIfStatement(BoundIfStatement node)
{
Debug.Assert(node != null);
var rewrittenCondition = (BoundExpression)Visit(node.Condition);
var rewrittenConsequence = (BoundStatement)Visit(node.Consequence);
var rewrittenAlternative = (BoundStatement)Visit(node.AlternativeOpt);
return RewriteIfStatement(node.Syntax, rewrittenCondition, rewrittenConsequence, rewrittenAlternative, node.HasErrors);
}
protected override BoundStatement RewriteIfStatement(BoundIfStatement node)
{
if (node.ElseStatement == null)
{
// if <condition>
// <then>
//
// ---->
//
// gotoFalse <condition> end
// <then>
// end:
var endLabel = GenerateLabel();
var gotoFalse = new BoundConditionalGotoStatement(endLabel, node.Condition, jumpIfTrue: false);
var endLabelStatement = new BoundLabelStatement(endLabel);
var result = new BoundBlockStatement(ImmutableArray.Create <BoundStatement>(
gotoFalse,
node.ThenStatement,
endLabelStatement
));
return(RewriteStatement(result));
}
else
{
// if <condition>
// <then>
// else
// <else>
//
// ---->
//
// gotoFalse <condition> else
// <then>
// goto end
// else:
// <else>
// end:
var elseLabel = GenerateLabel();
var endLabel = GenerateLabel();
var gotoFalse = new BoundConditionalGotoStatement(elseLabel, node.Condition, jumpIfTrue: false);
var gotoEndStatement = new BoundGotoStatement(endLabel);
var elseLabelStatement = new BoundLabelStatement(elseLabel);
var endLabelStatement = new BoundLabelStatement(endLabel);
var result = new BoundBlockStatement(ImmutableArray.Create <BoundStatement>(
gotoFalse,
node.ThenStatement,
gotoEndStatement,
elseLabelStatement,
node.ElseStatement,
endLabelStatement
));
return(RewriteStatement(result));
}
}
