private BoundExpression HoistRefInitialization(SynthesizedLocal local, BoundAssignmentOperator node)
{
Debug.Assert(local.SynthesizedKind == SynthesizedLocalKind.Spill);
Debug.Assert(local.SyntaxOpt != null);
Debug.Assert(this.OriginalMethod.IsAsync);
var right = (BoundExpression)Visit(node.Right);
var sideEffects = ArrayBuilder <BoundExpression> .GetInstance();
bool needsSacrificialEvaluation = false;
var hoistedFields = ArrayBuilder <StateMachineFieldSymbol> .GetInstance();
SyntaxNode awaitSyntaxOpt;
int syntaxOffset;
if (F.Compilation.Options.OptimizationLevel == OptimizationLevel.Debug)
{
awaitSyntaxOpt = local.GetDeclaratorSyntax();
Debug.Assert(awaitSyntaxOpt.IsKind(SyntaxKind.AwaitExpression) || awaitSyntaxOpt.IsKind(SyntaxKind.SwitchExpression));
syntaxOffset = OriginalMethod.CalculateLocalSyntaxOffset(LambdaUtilities.GetDeclaratorPosition(awaitSyntaxOpt), awaitSyntaxOpt.SyntaxTree);
}
else
{
// These are only used to calculate debug id for ref-spilled variables,
// no need to do so in release build.
awaitSyntaxOpt = null;
syntaxOffset = -1;
}
var replacement = HoistExpression(right, awaitSyntaxOpt, syntaxOffset, local.RefKind, sideEffects, hoistedFields, ref needsSacrificialEvaluation);
proxies.Add(local, new CapturedToExpressionSymbolReplacement(replacement, hoistedFields.ToImmutableAndFree(), isReusable: true));
if (needsSacrificialEvaluation)
{
var type = TypeMap.SubstituteType(local.Type).Type;
var sacrificialTemp = F.SynthesizedLocal(type, refKind: RefKind.Ref);
Debug.Assert(TypeSymbol.Equals(type, replacement.Type, TypeCompareKind.ConsiderEverything2));
return(F.Sequence(ImmutableArray.Create(sacrificialTemp), sideEffects.ToImmutableAndFree(), F.AssignmentExpression(F.Local(sacrificialTemp), replacement, isRef: true)));
}
if (sideEffects.Count == 0)
{
sideEffects.Free();
return(null);
}
var last = sideEffects.Last();
sideEffects.RemoveLast();
return(F.Sequence(ImmutableArray <LocalSymbol> .Empty, sideEffects.ToImmutableAndFree(), last));
}
