public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
BoundExpression expression = (BoundExpression)this.Visit(node.Expression);
TypeSymbol type = this.VisitType(node.Type);
return(node.Update(expression, VisitMethodSymbol(node.GetAwaiter), VisitPropertySymbol(node.IsCompleted), VisitMethodSymbol(node.GetResult), type));
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
// An await expression has already been wrapped in a BoundSpillSequence if not at the top level, so
// the spilling will occur in the enclosing node.
BoundSpillSequenceBuilder builder = null;
var expr = VisitExpression(ref builder, node.Expression);
return(UpdateExpression(builder, node.Update(expr, node.AwaitableInfo, node.Type)));
}
private BoundBlock VisitAwaitExpression(BoundAwaitExpression node, BoundExpression resultPlace)
{
var expression = (BoundExpression)Visit(node.Expression);
resultPlace = (BoundExpression)Visit(resultPlace);
MethodSymbol getAwaiter = VisitMethodSymbol(node.AwaitableInfo.GetAwaiter);
MethodSymbol getResult = VisitMethodSymbol(node.AwaitableInfo.GetResult);
MethodSymbol isCompletedMethod = ((object)node.AwaitableInfo.IsCompleted != null) ? VisitMethodSymbol(node.AwaitableInfo.IsCompleted.GetMethod) : null;
TypeSymbol type = VisitType(node.Type);
// The awaiter temp facilitates EnC method remapping and thus have to be long-lived.
// It transfers the awaiter objects from the old version of the MoveNext method to the new one.
Debug.Assert(node.Syntax.IsKind(SyntaxKind.AwaitExpression) || node.WasCompilerGenerated);
TypeSymbol awaiterType = getAwaiter.ReturnType.TypeSymbol;
var awaiterTemp = F.SynthesizedLocal(awaiterType, syntax: node.Syntax, kind: SynthesizedLocalKind.Awaiter);
var awaitIfIncomplete = F.Block(
// temp $awaiterTemp = <expr>.GetAwaiter();
F.Assignment(
F.Local(awaiterTemp),
MakeCallMaybeDynamic(expression, getAwaiter, WellKnownMemberNames.GetAwaiter)),
// hidden sequence point facilitates EnC method remapping, see explanation on SynthesizedLocalKind.Awaiter:
F.HiddenSequencePoint(),
// if(!($awaiterTemp.IsCompleted)) { ... }
F.If(
condition: F.Not(GenerateGetIsCompleted(awaiterTemp, isCompletedMethod)),
thenClause: GenerateAwaitForIncompleteTask(awaiterTemp)));
BoundExpression getResultCall = MakeCallMaybeDynamic(
F.Local(awaiterTemp),
getResult,
WellKnownMemberNames.GetResult,
resultsDiscarded: resultPlace == null);
// [$resultPlace = ] $awaiterTemp.GetResult();
BoundStatement getResultStatement = resultPlace != null && type.SpecialType != SpecialType.System_Void ?
F.Assignment(resultPlace, getResultCall) :
F.ExpressionStatement(getResultCall);
return(F.Block(
ImmutableArray.Create(awaiterTemp),
awaitIfIncomplete,
getResultStatement));
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
BoundExpression expression = (BoundExpression)this.Visit(node.Expression);
TypeSymbol type = this.VisitType(node.Type);
return node.Update(expression, VisitMethodSymbol(node.GetAwaiter), VisitPropertySymbol(node.IsCompleted), VisitMethodSymbol(node.GetResult), type);
}
public sealed override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
// await expressions must, by now, have been moved to the top level.
throw ExceptionUtilities.Unreachable;
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
_sawAwait = true;
return(null);
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
_seenAwait = true;
return(base.VisitAwaitExpression(node));
}
public BoundExpression VisitAwaitExpression(BoundAwaitExpression node, bool used)
{
return(RewriteAwaitExpression((BoundExpression)base.VisitAwaitExpression(node), used));
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
return(VisitAwaitExpression(node, true));
}
