public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
var ss = new BoundSpillSequence2();
var replacement = VisitExpression(ref ss, node);
return(ss.Update(replacement));
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
var builder = new BoundSpillSequenceBuilder();
var replacement = VisitExpression(ref builder, node);
return(builder.Update(replacement));
}
private BoundBlock VisitAwaitExpression(BoundAwaitExpression node, BoundExpression resultPlace)
{
var expression = (BoundExpression)Visit(node.Expression);
var awaitablePlaceholder = node.AwaitableInfo.AwaitableInstancePlaceholder;
if (awaitablePlaceholder != null)
{
_placeholderMap.Add(awaitablePlaceholder, expression);
}
var getAwaiter = node.AwaitableInfo.IsDynamic ?
MakeCallMaybeDynamic(expression, null, WellKnownMemberNames.GetAwaiter) :
(BoundExpression)Visit(node.AwaitableInfo.GetAwaiter);
resultPlace = (BoundExpression)Visit(resultPlace);
MethodSymbol getResult = VisitMethodSymbol(node.AwaitableInfo.GetResult);
MethodSymbol isCompletedMethod = ((object)node.AwaitableInfo.IsCompleted != null) ? VisitMethodSymbol(node.AwaitableInfo.IsCompleted.GetMethod) : null;
TypeSymbol type = VisitType(node.Type);
if (awaitablePlaceholder != null)
{
_placeholderMap.Remove(awaitablePlaceholder);
}
// 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);
var awaiterTemp = F.SynthesizedLocal(getAwaiter.Type, syntax: node.Syntax, kind: SynthesizedLocalKind.Awaiter);
var awaitIfIncomplete = F.Block(
// temp $awaiterTemp = <expr>.GetAwaiter();
F.Assignment(
F.Local(awaiterTemp),
getAwaiter),
// hidden sequence point facilitates EnC method remapping, see explanation on SynthesizedLocalKind.Awaiter:
F.HiddenSequencePoint(),
// if(!($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.IsVoidType() ?
F.Assignment(resultPlace, getResultCall) :
F.ExpressionStatement(getResultCall);
return(F.Block(
ImmutableArray.Create(awaiterTemp),
awaitIfIncomplete,
getResultStatement));
}
private BoundBlock VisitAwaitExpression(BoundAwaitExpression node, BoundExpression resultPlace)
{
var expression = (BoundExpression)Visit(node.Expression);
resultPlace = (BoundExpression)Visit(resultPlace);
MethodSymbol getAwaiter = VisitMethodSymbol(node.GetAwaiter);
MethodSymbol getResult = VisitMethodSymbol(node.GetResult);
MethodSymbol isCompletedMethod = ((object)node.IsCompleted != null) ? VisitMethodSymbol(node.IsCompleted.GetMethod) : null;
TypeSymbol type = VisitType(node.Type);
// The lifespan of awaiter temp doesn't cross sequence points (user code in between awaits), so it doesn't need to be named.
TypeSymbol awaiterType = node.IsDynamic ? DynamicTypeSymbol.Instance : getAwaiter.ReturnType;
var awaiterTemp = F.SynthesizedLocal(awaiterType);
var awaitIfIncomplete = F.Block(
// temp $awaiterTemp = <expr>.GetAwaiter();
F.Assignment(
F.Local(awaiterTemp),
MakeCallMaybeDynamic(expression, getAwaiter, WellKnownMemberNames.GetAwaiter)),
// if(!($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);
var nullAwaiter = F.AssignmentExpression(F.Local(awaiterTemp), F.NullOrDefault(awaiterTemp.Type));
if (resultPlace != null && type.SpecialType != SpecialType.System_Void)
{
// $resultTemp = $awaiterTemp.GetResult();
// $awaiterTemp = null;
// $resultTemp
LocalSymbol resultTemp = F.SynthesizedLocal(type);
return(F.Block(
ImmutableArray.Create(awaiterTemp, resultTemp),
awaitIfIncomplete,
F.Assignment(F.Local(resultTemp), getResultCall),
F.ExpressionStatement(nullAwaiter),
F.Assignment(resultPlace, F.Local(resultTemp))));
}
else
{
// $awaiterTemp.GetResult();
// $awaiterTemp = null;
return(F.Block(
ImmutableArray.Create(awaiterTemp),
awaitIfIncomplete,
F.ExpressionStatement(getResultCall),
F.ExpressionStatement(nullAwaiter)));
}
}
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)));
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
if (this.ExceptionHandleNesting != 0)
{
Debug.Assert(this.ExceptionHandleNesting > 0);
this.sawAwaitInExceptionHandler = true;
}
return(base.VisitAwaitExpression(node));
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
if (this.ExceptionHandleNesting != 0)
{
Debug.Assert(this.ExceptionHandleNesting > 0);
this.sawAwaitInExceptionHandler = true;
}
return base.VisitAwaitExpression(node);
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
return(VisitAwaitExpression(node, resultsDiscarded: false));
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
// await expressions must, by now, have been moved to the top level.
throw ExceptionUtilities.Unreachable;
}
private BoundExpression VisitAwaitExpression(BoundAwaitExpression node, bool resultsDiscarded)
{
var expression = (BoundExpression)Visit(node.Expression);
MethodSymbol getAwaiter = VisitMethodSymbol(node.GetAwaiter);
MethodSymbol getResult = VisitMethodSymbol(node.GetResult);
MethodSymbol isCompletedMethod = (node.IsCompleted != null) ? VisitMethodSymbol(node.IsCompleted.GetMethod) : null;
TypeSymbol type = VisitType(node.Type);
LocalSymbol awaiterTemp;
if (getResult == null)
{
awaiterTemp = F.SynthesizedLocal(DynamicTypeSymbol.Instance, name: null);
}
else if (type.IsDynamic())
{
var awaiterType = ((NamedTypeSymbol)getAwaiter.ReturnType).OriginalNamedTypeDefinition.Construct(F.SpecialType(SpecialType.System_Object));
awaiterTemp = F.SynthesizedLocal(awaiterType, null);
getResult = ((MethodSymbol)getResult.OriginalDefinition).AsMember(awaiterType);
isCompletedMethod = ((MethodSymbol)isCompletedMethod.OriginalDefinition).AsMember(awaiterType);
}
else
{
awaiterTemp = F.SynthesizedLocal(getAwaiter.ReturnType, name: null);
}
var awaitIfIncomplete = F.Block(
// temp $awaiterTemp = <expr>.GetAwaiter();
F.Assignment(
F.Local(awaiterTemp),
MakeCallMaybeDynamic(expression, getAwaiter, "GetAwaiter")),
// if(!($awaiterTemp.IsCompleted)) { ... }
F.If(
condition: F.Not(GenerateGetIsCompleted(awaiterTemp, isCompletedMethod)),
thenClause: GenerateAwaitForIncompleteTask(awaiterTemp)));
BoundExpression getResultCall = MakeCallMaybeDynamic(
F.Local(awaiterTemp),
getResult,
"GetResult",
resultsDiscarded: resultsDiscarded);
var nullAwaiter = F.AssignmentExpression(F.Local(awaiterTemp), F.NullOrDefault(awaiterTemp.Type));
BoundExpression onAwaitFinished;
if (!resultsDiscarded && type.SpecialType != SpecialType.System_Void)
{
// $resultTemp = $awaiterTemp.GetResult();
// $awaiterTemp = null;
// $resultTemp
LocalSymbol resultTemp = F.SynthesizedLocal(type, null);
onAwaitFinished = F.Sequence(
resultTemp,
F.AssignmentExpression(F.Local(resultTemp), getResultCall),
nullAwaiter,
F.Local(resultTemp));
}
else
{
// $awaiterTemp.GetResult();
// $awaiterTemp = null;
onAwaitFinished = F.Sequence(
ReadOnlyArray <LocalSymbol> .Empty,
getResultCall,
nullAwaiter);
}
return(F.SpillSequence(
ReadOnlyArray <LocalSymbol> .CreateFrom(awaiterTemp),
ReadOnlyArray <BoundSpillTemp> .Empty,
ReadOnlyArray <FieldSymbol> .Empty,
ReadOnlyArray <BoundStatement> .CreateFrom(awaitIfIncomplete),
onAwaitFinished));
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
base.VisitAwaitExpression(node);
MarkLocalsUnassigned();
return null;
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
return VisitAwaitExpression(node, resultsDiscarded: false);
}
private BoundExpression VisitAwaitExpression(BoundAwaitExpression node, bool resultsDiscarded)
{
var expression = (BoundExpression)Visit(node.Expression);
MethodSymbol getAwaiter = VisitMethodSymbol(node.GetAwaiter);
MethodSymbol getResult = VisitMethodSymbol(node.GetResult);
MethodSymbol isCompletedMethod = (node.IsCompleted != null) ? VisitMethodSymbol(node.IsCompleted.GetMethod) : null;
TypeSymbol type = VisitType(node.Type);
LocalSymbol awaiterTemp;
if (getResult == null)
{
awaiterTemp = F.SynthesizedLocal(DynamicTypeSymbol.Instance, name: null);
}
else if (type.IsDynamic())
{
var awaiterType = ((NamedTypeSymbol)getAwaiter.ReturnType).OriginalNamedTypeDefinition.Construct(F.SpecialType(SpecialType.System_Object));
awaiterTemp = F.SynthesizedLocal(awaiterType, null);
getResult = ((MethodSymbol)getResult.OriginalDefinition).AsMember(awaiterType);
isCompletedMethod = ((MethodSymbol)isCompletedMethod.OriginalDefinition).AsMember(awaiterType);
}
else
{
awaiterTemp = F.SynthesizedLocal(getAwaiter.ReturnType, name: null);
}
var awaitIfIncomplete = F.Block(
// temp $awaiterTemp = <expr>.GetAwaiter();
F.Assignment(
F.Local(awaiterTemp),
MakeCallMaybeDynamic(expression, getAwaiter, "GetAwaiter")),
// if(!($awaiterTemp.IsCompleted)) { ... }
F.If(
condition: F.Not(GenerateGetIsCompleted(awaiterTemp, isCompletedMethod)),
thenClause: GenerateAwaitForIncompleteTask(awaiterTemp)));
BoundExpression getResultCall = MakeCallMaybeDynamic(
F.Local(awaiterTemp),
getResult,
"GetResult",
resultsDiscarded: resultsDiscarded);
var nullAwaiter = F.AssignmentExpression(F.Local(awaiterTemp), F.NullOrDefault(awaiterTemp.Type));
BoundExpression onAwaitFinished;
if (!resultsDiscarded && type.SpecialType != SpecialType.System_Void)
{
// $resultTemp = $awaiterTemp.GetResult();
// $awaiterTemp = null;
// $resultTemp
LocalSymbol resultTemp = F.SynthesizedLocal(type, null);
onAwaitFinished = F.Sequence(
resultTemp,
F.AssignmentExpression(F.Local(resultTemp), getResultCall),
nullAwaiter,
F.Local(resultTemp));
}
else
{
// $awaiterTemp.GetResult();
// $awaiterTemp = null;
onAwaitFinished = F.Sequence(
ReadOnlyArray<LocalSymbol>.Empty,
getResultCall,
nullAwaiter);
}
return F.SpillSequence(
ReadOnlyArray<LocalSymbol>.CreateFrom(awaiterTemp),
ReadOnlyArray<BoundSpillTemp>.Empty,
ReadOnlyArray<FieldSymbol>.Empty,
ReadOnlyArray<BoundStatement>.CreateFrom(awaitIfIncomplete),
onAwaitFinished);
}
private BoundStatement RewriteUsingStatementTryFinally(SyntaxNode syntax, BoundBlock tryBlock, BoundLocal local, SyntaxToken awaitKeywordOpt, AwaitableInfo awaitOpt)
{
// SPEC: When ResourceType is a non-nullable value type, the expansion is:
// SPEC:
// SPEC: {
// SPEC: ResourceType resource = expr;
// SPEC: try { statement; }
// SPEC: finally { ((IDisposable)resource).Dispose(); }
// SPEC: }
// SPEC:
// SPEC: Otherwise, when Resource type is a nullable value type or
// SPEC: a reference type other than dynamic, the expansion is:
// SPEC:
// SPEC: {
// SPEC: ResourceType resource = expr;
// SPEC: try { statement; }
// SPEC: finally { if (resource != null) ((IDisposable)resource).Dispose(); }
// SPEC: }
// SPEC:
// SPEC: Otherwise, when ResourceType is dynamic, the expansion is:
// SPEC: {
// SPEC: dynamic resource = expr;
// SPEC: IDisposable d = (IDisposable)resource;
// SPEC: try { statement; }
// SPEC: finally { if (d != null) d.Dispose(); }
// SPEC: }
// SPEC:
// SPEC: An implementation is permitted to implement a given using statement
// SPEC: differently -- for example, for performance reasons -- as long as the
// SPEC: behavior is consistent with the above expansion.
//
// In the case of using-await statement, we'll use "IAsyncDisposable" instead of "IDisposable", "await DisposeAsync()" instead of "Dispose()"
//
// And we do in fact generate the code slightly differently than precisely how it is
// described above.
//
// First: if the type is a non-nullable value type then we do not do the
// *boxing conversion* from the resource to IDisposable. Rather, we do
// a *constrained virtual call* that elides the boxing if possible.
//
// Now, you might wonder if that is legal; isn't skipping the boxing producing
// an observable difference? Because if the value type is mutable and the Dispose
// mutates it, then skipping the boxing means that we are now mutating the original,
// not the boxed copy. But this is never observable. Either (1) we have "using(R r = x){}"
// and r is out of scope after the finally, so it is not possible to observe the mutation,
// or (2) we have "using(x) {}". But that has the semantics of "using(R temp = x){}",
// so again, we are not mutating x to begin with; we're always mutating a copy. Therefore
// it doesn't matter if we skip making *a copy of the copy*.
//
// This is what the dev10 compiler does, and we do so as well.
//
// Second: if the type is a nullable value type then we can similarly elide the boxing.
// We can generate
//
// {
// ResourceType resource = expr;
// try { statement; }
// finally { if (resource.HasValue) resource.GetValueOrDefault().Dispose(); }
// }
//
// Where again we do a constrained virtual call to Dispose, rather than boxing
// the value to IDisposable.
//
// Note that this optimization is *not* what the native compiler does; in this case
// the native compiler behavior is to test for HasValue, then *box* and convert
// the boxed value to IDisposable. There's no need to do that.
//
// Third: if we have "using(x)" and x is dynamic then obviously we need not generate
// "{ dynamic temp1 = x; IDisposable temp2 = (IDisposable) temp1; ... }". Rather, we elide
// the completely unnecessary first temporary.
Debug.Assert((awaitKeywordOpt == default) == (awaitOpt == default(AwaitableInfo)));
BoundExpression disposedExpression;
bool isNullableValueType = local.Type.IsNullableType();
if (isNullableValueType)
{
MethodSymbol getValueOrDefault = UnsafeGetNullableMethod(syntax, local.Type, SpecialMember.System_Nullable_T_GetValueOrDefault);
// local.GetValueOrDefault()
disposedExpression = BoundCall.Synthesized(syntax, local, getValueOrDefault);
}
else
{
// local
disposedExpression = local;
}
BoundExpression disposeCall;
if (awaitOpt == null && Binder.TryGetSpecialTypeMember(_compilation, SpecialMember.System_IDisposable__Dispose, syntax, _diagnostics, out MethodSymbol disposeMethodSymbol))
{
// local.Dispose()
disposeCall = BoundCall.Synthesized(syntax, disposedExpression, disposeMethodSymbol);
}
else if (awaitOpt != null &&
TryGetWellKnownTypeMember(syntax: null, WellKnownMember.System_IAsyncDisposable__DisposeAsync,
out MethodSymbol disposeAsyncMethodSymbol, location: awaitKeywordOpt.GetLocation()))
{
// await local.DisposeAsync()
_sawAwaitInExceptionHandler = true;
var callExpr = BoundCall.Synthesized(syntax, disposedExpression, disposeAsyncMethodSymbol);
TypeSymbol awaitExpressionType = awaitOpt.GetResult?.ReturnType.TypeSymbol ?? _compilation.DynamicType;
BoundAwaitExpression awaitExpr = new BoundAwaitExpression(syntax, callExpr, awaitOpt, awaitExpressionType)
{
WasCompilerGenerated = true
};
disposeCall = (BoundExpression)VisitAwaitExpression(awaitExpr);
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
_seenAwait = true;
return base.VisitAwaitExpression(node);
}
private BoundBlock VisitAwaitExpression(BoundAwaitExpression node, BoundExpression resultPlace)
{
var expression = (BoundExpression)Visit(node.Expression);
resultPlace = (BoundExpression)Visit(resultPlace);
MethodSymbol getAwaiter = VisitMethodSymbol(node.GetAwaiter);
MethodSymbol getResult = VisitMethodSymbol(node.GetResult);
MethodSymbol isCompletedMethod = ((object)node.IsCompleted != null) ? VisitMethodSymbol(node.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));
TypeSymbol awaiterType = node.IsDynamic ? DynamicTypeSymbol.Instance : getAwaiter.ReturnType;
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);
var nullAwaiter = F.AssignmentExpression(F.Local(awaiterTemp), F.NullOrDefault(awaiterTemp.Type));
if (resultPlace != null && type.SpecialType != SpecialType.System_Void)
{
// $resultTemp = $awaiterTemp.GetResult();
// $awaiterTemp = null;
// $resultTemp
LocalSymbol resultTemp = F.SynthesizedLocal(type);
return(F.Block(
ImmutableArray.Create(awaiterTemp, resultTemp),
awaitIfIncomplete,
F.Assignment(F.Local(resultTemp), getResultCall),
F.ExpressionStatement(nullAwaiter),
F.Assignment(resultPlace, F.Local(resultTemp))));
}
else
{
// $awaiterTemp.GetResult();
// $awaiterTemp = null;
return(F.Block(
ImmutableArray.Create(awaiterTemp),
awaitIfIncomplete,
F.ExpressionStatement(getResultCall),
F.ExpressionStatement(nullAwaiter)));
}
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
_seenAwait = true;
return(base.VisitAwaitExpression(node));
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
var ss = new BoundSpillSequence2();
var replacement = VisitExpression(ref ss, node);
return ss.Update(replacement);
}
public BoundExpression VisitAwaitExpression(BoundAwaitExpression node, bool used)
{
return(RewriteAwaitExpression((BoundExpression)base.VisitAwaitExpression(node) !, used));
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
return(VisitAwaitExpression(node, true));
}
private BoundBlock VisitAwaitExpression(BoundAwaitExpression node, BoundExpression resultPlace)
{
var expression = (BoundExpression)Visit(node.Expression);
resultPlace = (BoundExpression)Visit(resultPlace);
MethodSymbol getAwaiter = VisitMethodSymbol(node.GetAwaiter);
MethodSymbol getResult = VisitMethodSymbol(node.GetResult);
MethodSymbol isCompletedMethod = ((object)node.IsCompleted != null) ? VisitMethodSymbol(node.IsCompleted.GetMethod) : null;
TypeSymbol type = VisitType(node.Type);
LocalSymbol awaiterTemp;
if ((object)getResult == null)
{
awaiterTemp = F.SynthesizedLocal(DynamicTypeSymbol.Instance);
}
else if (type.IsDynamic())
{
var awaiterType = ((NamedTypeSymbol)getAwaiter.ReturnType).OriginalDefinition.Construct(F.SpecialType(SpecialType.System_Object));
awaiterTemp = F.SynthesizedLocal(awaiterType);
getResult = ((MethodSymbol)getResult.OriginalDefinition).AsMember(awaiterType);
isCompletedMethod = ((MethodSymbol)isCompletedMethod.OriginalDefinition).AsMember(awaiterType);
}
else
{
awaiterTemp = F.SynthesizedLocal(getAwaiter.ReturnType);
}
var awaitIfIncomplete = F.Block(
// temp $awaiterTemp = <expr>.GetAwaiter();
F.Assignment(
F.Local(awaiterTemp),
MakeCallMaybeDynamic(expression, getAwaiter, WellKnownMemberNames.GetAwaiter)),
// if(!($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);
var nullAwaiter = F.AssignmentExpression(F.Local(awaiterTemp), F.NullOrDefault(awaiterTemp.Type));
if (resultPlace != null && type.SpecialType != SpecialType.System_Void)
{
// $resultTemp = $awaiterTemp.GetResult();
// $awaiterTemp = null;
// $resultTemp
LocalSymbol resultTemp = F.SynthesizedLocal(type);
return(F.Block(
ImmutableArray.Create <LocalSymbol>(awaiterTemp, resultTemp),
awaitIfIncomplete,
F.Assignment(F.Local(resultTemp), getResultCall),
F.ExpressionStatement(nullAwaiter),
F.Assignment(resultPlace, F.Local(resultTemp))));
}
else
{
// $awaiterTemp.GetResult();
// $awaiterTemp = null;
return(F.Block(
ImmutableArray.Create <LocalSymbol>(awaiterTemp),
awaitIfIncomplete,
F.ExpressionStatement(getResultCall),
F.ExpressionStatement(nullAwaiter)));
}
}
private BoundBlock VisitAwaitExpression(BoundAwaitExpression node, BoundExpression resultPlace)
{
var expression = (BoundExpression)Visit(node.Expression);
resultPlace = (BoundExpression)Visit(resultPlace);
MethodSymbol getAwaiter = VisitMethodSymbol(node.GetAwaiter);
MethodSymbol getResult = VisitMethodSymbol(node.GetResult);
MethodSymbol isCompletedMethod = ((object)node.IsCompleted != null) ? VisitMethodSymbol(node.IsCompleted.GetMethod) : null;
TypeSymbol type = VisitType(node.Type);
LocalSymbol awaiterTemp;
if ((object)getResult == null)
{
awaiterTemp = F.SynthesizedLocal(DynamicTypeSymbol.Instance);
}
else if (type.IsDynamic())
{
var awaiterType = ((NamedTypeSymbol)getAwaiter.ReturnType).OriginalDefinition.Construct(F.SpecialType(SpecialType.System_Object));
awaiterTemp = F.SynthesizedLocal(awaiterType);
getResult = ((MethodSymbol)getResult.OriginalDefinition).AsMember(awaiterType);
isCompletedMethod = ((MethodSymbol)isCompletedMethod.OriginalDefinition).AsMember(awaiterType);
}
else
{
awaiterTemp = F.SynthesizedLocal(getAwaiter.ReturnType);
}
var awaitIfIncomplete = F.Block(
// temp $awaiterTemp = <expr>.GetAwaiter();
F.Assignment(
F.Local(awaiterTemp),
MakeCallMaybeDynamic(expression, getAwaiter, WellKnownMemberNames.GetAwaiter)),
// if(!($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);
var nullAwaiter = F.AssignmentExpression(F.Local(awaiterTemp), F.NullOrDefault(awaiterTemp.Type));
if (resultPlace != null && type.SpecialType != SpecialType.System_Void)
{
// $resultTemp = $awaiterTemp.GetResult();
// $awaiterTemp = null;
// $resultTemp
LocalSymbol resultTemp = F.SynthesizedLocal(type);
return F.Block(
ImmutableArray.Create<LocalSymbol>(awaiterTemp, resultTemp),
awaitIfIncomplete,
F.Assignment(F.Local(resultTemp), getResultCall),
F.ExpressionStatement(nullAwaiter),
F.Assignment(resultPlace, F.Local(resultTemp)));
}
else
{
// $awaiterTemp.GetResult();
// $awaiterTemp = null;
return F.Block(
ImmutableArray.Create<LocalSymbol>(awaiterTemp),
awaitIfIncomplete,
F.ExpressionStatement(getResultCall),
F.ExpressionStatement(nullAwaiter));
}
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
// await expressions must, by now, have been moved to the top level.
throw ExceptionUtilities.Unreachable;
}
private BoundBlock VisitAwaitExpression(BoundAwaitExpression node, BoundExpression resultPlace)
{
var expression = (BoundExpression)Visit(node.Expression);
resultPlace = (BoundExpression)Visit(resultPlace);
MethodSymbol getAwaiter = VisitMethodSymbol(node.GetAwaiter);
MethodSymbol getResult = VisitMethodSymbol(node.GetResult);
MethodSymbol isCompletedMethod = ((object)node.IsCompleted != null) ? VisitMethodSymbol(node.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));
TypeSymbol awaiterType = node.IsDynamic ? DynamicTypeSymbol.Instance : getAwaiter.ReturnType;
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);
var nullAwaiter = F.AssignmentExpression(F.Local(awaiterTemp), F.NullOrDefault(awaiterTemp.Type));
if (resultPlace != null && type.SpecialType != SpecialType.System_Void)
{
// $resultTemp = $awaiterTemp.GetResult();
// $awaiterTemp = null;
// $resultTemp
LocalSymbol resultTemp = F.SynthesizedLocal(type);
return F.Block(
ImmutableArray.Create(awaiterTemp, resultTemp),
ImmutableArray<LocalFunctionSymbol>.Empty,
awaitIfIncomplete,
F.Assignment(F.Local(resultTemp), getResultCall),
F.ExpressionStatement(nullAwaiter),
F.Assignment(resultPlace, F.Local(resultTemp)));
}
else
{
// $awaiterTemp.GetResult();
// $awaiterTemp = null;
return F.Block(
ImmutableArray.Create(awaiterTemp),
ImmutableArray<LocalFunctionSymbol>.Empty,
awaitIfIncomplete,
F.ExpressionStatement(getResultCall),
F.ExpressionStatement(nullAwaiter));
}
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
base.VisitAwaitExpression(node);
MarkLocalsUnassigned();
return(null);
}
public override BoundNode VisitAwaitExpression(BoundAwaitExpression node)
{
_sawAwait = true;
return(null);
}
public override BoundNode?VisitAwaitExpression(BoundAwaitExpression node)
{
ContainsAwait = true;
return(null);
}
private BoundBlock VisitAwaitExpression(BoundAwaitExpression node, BoundExpression resultPlace)
{
var expression = (BoundExpression)Visit(node.Expression);
resultPlace = (BoundExpression)Visit(resultPlace);
MethodSymbol getAwaiter = VisitMethodSymbol(node.GetAwaiter);
MethodSymbol getResult = VisitMethodSymbol(node.GetResult);
MethodSymbol isCompletedMethod = ((object)node.IsCompleted != null) ? VisitMethodSymbol(node.IsCompleted.GetMethod) : null;
TypeSymbol type = VisitType(node.Type);
// The lifespan of awaiter temp doesn't cross sequence points (user code in between awaits), so it doesn't need to be named.
TypeSymbol awaiterType = node.IsDynamic ? DynamicTypeSymbol.Instance : getAwaiter.ReturnType;
var awaiterTemp = F.SynthesizedLocal(awaiterType);
var awaitIfIncomplete = F.Block(
// temp $awaiterTemp = <expr>.GetAwaiter();
F.Assignment(
F.Local(awaiterTemp),
MakeCallMaybeDynamic(expression, getAwaiter, WellKnownMemberNames.GetAwaiter)),
// if(!($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);
var nullAwaiter = F.AssignmentExpression(F.Local(awaiterTemp), F.NullOrDefault(awaiterTemp.Type));
if (resultPlace != null && type.SpecialType != SpecialType.System_Void)
{
// $resultTemp = $awaiterTemp.GetResult();
// $awaiterTemp = null;
// $resultTemp
LocalSymbol resultTemp = F.SynthesizedLocal(type);
return F.Block(
ImmutableArray.Create(awaiterTemp, resultTemp),
awaitIfIncomplete,
F.Assignment(F.Local(resultTemp), getResultCall),
F.ExpressionStatement(nullAwaiter),
F.Assignment(resultPlace, F.Local(resultTemp)));
}
else
{
// $awaiterTemp.GetResult();
// $awaiterTemp = null;
return F.Block(
ImmutableArray.Create(awaiterTemp),
awaitIfIncomplete,
F.ExpressionStatement(getResultCall),
F.ExpressionStatement(nullAwaiter));
}
}