private void AccessTupleFields(BoundDeconstructionAssignmentOperator node, BoundDeconstructionDeconstructStep deconstruction, ArrayBuilder<LocalSymbol> temps, ArrayBuilder<BoundExpression> stores, ArrayBuilder<BoundValuePlaceholderBase> placeholders)
{
var target = PlaceholderReplacement(deconstruction.TargetPlaceholder);
var tupleType = target.Type.IsTupleType ? target.Type : TupleTypeSymbol.Create((NamedTypeSymbol)target.Type);
var tupleElementTypes = tupleType.TupleElementTypes;
var numElements = tupleElementTypes.Length;
CSharpSyntaxNode syntax = node.Syntax;
// save the target as we need to access it multiple times
BoundAssignmentOperator assignmentToTemp;
var savedTuple = _factory.StoreToTemp(target, out assignmentToTemp);
stores.Add(assignmentToTemp);
temps.Add(savedTuple.LocalSymbol);
// list the tuple fields accessors
var fields = tupleType.TupleElementFields;
for (int i = 0; i < numElements; i++)
{
var field = fields[i];
DiagnosticInfo useSiteInfo = field.GetUseSiteDiagnostic();
if ((object)useSiteInfo != null && useSiteInfo.Severity == DiagnosticSeverity.Error)
{
Symbol.ReportUseSiteDiagnostic(useSiteInfo, _diagnostics, syntax.Location);
}
var fieldAccess = MakeTupleFieldAccess(syntax, field, savedTuple, null, LookupResultKind.Empty);
AddPlaceholderReplacement(deconstruction.OutputPlaceholders[i], fieldAccess);
placeholders.Add(deconstruction.OutputPlaceholders[i]);
}
}
public override BoundNode VisitDeconstructionAssignmentOperator(BoundDeconstructionAssignmentOperator node)
{
var temps = ArrayBuilder<LocalSymbol>.GetInstance();
var stores = ArrayBuilder<BoundExpression>.GetInstance();
var placeholders = ArrayBuilder<BoundValuePlaceholderBase>.GetInstance();
// evaluate left-hand-side side-effects
ImmutableArray<BoundExpression> lhsTargets = LeftHandSideSideEffects(node.LeftVariables, temps, stores);
// get or make right-hand-side values
BoundExpression loweredRight = VisitExpression(node.Right);
ApplyDeconstructions(node, temps, stores, placeholders, loweredRight);
ApplyConversions(node, temps, stores, placeholders);
ApplyAssignments(node, stores, lhsTargets);
BoundExpression returnValue = MakeReturnValue(node, placeholders);
BoundExpression result = _factory.Sequence(temps.ToImmutable(), stores.ToImmutable(), returnValue);
RemovePlaceholderReplacements(placeholders);
placeholders.Free();
temps.Free();
stores.Free();
return result;
}
/// <summary>
/// Applies the conversions.
/// Adds any new locals to the temps and any new expressions to be evaluated to the stores.
/// </summary>
private void ApplyConversions(BoundDeconstructionAssignmentOperator node, ArrayBuilder<LocalSymbol> temps, ArrayBuilder<BoundExpression> stores, ArrayBuilder<BoundValuePlaceholderBase> placeholders)
{
int numConversions = node.ConversionSteps.Length;
var conversionLocals = ArrayBuilder<BoundExpression>.GetInstance();
foreach (var conversionInfo in node.ConversionSteps)
{
// lower the conversions and assignments to locals
var localSymbol = new SynthesizedLocal(_factory.CurrentMethod, conversionInfo.OutputPlaceholder.Type, SynthesizedLocalKind.LoweringTemp);
var localBound = new BoundLocal(node.Syntax,
localSymbol,
null,
conversionInfo.OutputPlaceholder.Type)
{ WasCompilerGenerated = true };
temps.Add(localSymbol);
conversionLocals.Add(localBound);
AddPlaceholderReplacement(conversionInfo.OutputPlaceholder, localBound);
placeholders.Add(conversionInfo.OutputPlaceholder);
var conversion = VisitExpression(conversionInfo.Assignment);
stores.Add(conversion);
}
}
public override BoundNode VisitDeconstructionAssignmentOperator(BoundDeconstructionAssignmentOperator node)
{
Debug.Assert(node.DeconstructSteps != null);
Debug.Assert(node.AssignmentSteps != null);
var temps = ArrayBuilder<LocalSymbol>.GetInstance();
var stores = ArrayBuilder<BoundExpression>.GetInstance();
var placeholders = ArrayBuilder<BoundValuePlaceholderBase>.GetInstance();
// evaluate left-hand-side side-effects
var lhsTargets = LeftHandSideSideEffects(node.LeftVariables, temps, stores);
// get or make right-hand-side values
BoundExpression loweredRight = VisitExpression(node.Right);
AddPlaceholderReplacement(node.DeconstructSteps[0].TargetPlaceholder, loweredRight);
placeholders.Add(node.DeconstructSteps[0].TargetPlaceholder);
foreach (var deconstruction in node.DeconstructSteps)
{
if (deconstruction.DeconstructInvocationOpt == null)
{
// tuple case
AccessTupleFields(node, deconstruction, temps, stores, placeholders);
}
else
{
CallDeconstruct(node, deconstruction, temps, stores, placeholders);
}
}
int numAssignments = node.AssignmentSteps.Length;
for (int i = 0; i < numAssignments; i++)
{
// lower the assignment and replace the placeholders for its outputs in the process
var assignmentInfo = node.AssignmentSteps[i];
AddPlaceholderReplacement(assignmentInfo.OutputPlaceholder, lhsTargets[i]);
var assignment = VisitExpression(assignmentInfo.Assignment);
RemovePlaceholderReplacement(assignmentInfo.OutputPlaceholder);
stores.Add(assignment);
}
var result = _factory.Sequence(temps.ToImmutable(), stores.ToImmutable(), new BoundVoid(node.Syntax, node.Type));
RemovePlaceholderReplacements(placeholders);
placeholders.Free();
temps.Free();
stores.Free();
return result;
}
/// <summary>
/// Applies the deconstructions.
/// Adds any new locals to the temps and any new expressions to be evaluated to the stores.
/// </summary>
private void ApplyDeconstructions(BoundDeconstructionAssignmentOperator node, ArrayBuilder<LocalSymbol> temps, ArrayBuilder<BoundExpression> stores, ArrayBuilder<BoundValuePlaceholderBase> placeholders, BoundExpression loweredRight)
{
var firstDeconstructStep = node.DeconstructSteps[0];
AddPlaceholderReplacement(firstDeconstructStep.InputPlaceholder, loweredRight);
placeholders.Add(firstDeconstructStep.InputPlaceholder);
foreach (BoundDeconstructionDeconstructStep deconstruction in node.DeconstructSteps)
{
if (deconstruction.DeconstructInvocationOpt == null)
{
// tuple case
AccessTupleFields(node, deconstruction, temps, stores, placeholders);
}
else
{
CallDeconstruct(node, deconstruction, temps, stores, placeholders);
}
}
}
/// <summary>
/// Prepares local variables to be used in Deconstruct call
/// Adds a invocation of Deconstruct with those as out parameters onto the 'stores' sequence
/// Returns the expressions for those out parameters
/// </summary>
private void CallDeconstruct(BoundDeconstructionAssignmentOperator node, BoundDeconstructionDeconstructStep deconstruction, ArrayBuilder<LocalSymbol> temps, ArrayBuilder<BoundExpression> stores, ArrayBuilder<BoundValuePlaceholderBase> placeholders)
{
Debug.Assert((object)deconstruction.DeconstructInvocationOpt != null);
CSharpSyntaxNode syntax = node.Syntax;
// prepare out parameters for Deconstruct
var deconstructParameters = deconstruction.OutputPlaceholders;
var outParametersBuilder = ArrayBuilder<BoundExpression>.GetInstance(deconstructParameters.Length);
for (var i = 0; i < deconstructParameters.Length; i++)
{
var deconstructParameter = deconstructParameters[i];
var localSymbol = new SynthesizedLocal(_factory.CurrentMethod, deconstructParameter.Type, SynthesizedLocalKind.LoweringTemp);
var localBound = new BoundLocal(syntax,
localSymbol,
null,
deconstructParameter.Type
)
{ WasCompilerGenerated = true };
temps.Add(localSymbol);
outParametersBuilder.Add(localBound);
AddPlaceholderReplacement(deconstruction.OutputPlaceholders[i], localBound);
placeholders.Add(deconstruction.OutputPlaceholders[i]);
}
var outParameters = outParametersBuilder.ToImmutableAndFree();
// invoke Deconstruct with placeholders replaced by locals
stores.Add(VisitExpression(deconstruction.DeconstructInvocationOpt));
}
public override BoundNode VisitDeconstructionAssignmentOperator(BoundDeconstructionAssignmentOperator node)
{
return this.SetMayHaveSideEffects();
}
/// <summary>
/// Applies the assignments.
/// Adds any new expressions to be evaluated to the stores.
/// </summary>
private void ApplyAssignments(BoundDeconstructionAssignmentOperator node, ArrayBuilder<BoundExpression> stores, ImmutableArray<BoundExpression> lhsTargets)
{
int numAssignments = node.AssignmentSteps.Length;
for (int i = 0; i < numAssignments; i++)
{
var assignmentInfo = node.AssignmentSteps[i];
AddPlaceholderReplacement(assignmentInfo.OutputPlaceholder, lhsTargets[i]);
var assignment = assignmentInfo.Assignment;
// All the input placeholders for the assignments should already be set with lowered nodes
Debug.Assert(assignment.Left.Kind == BoundKind.DeconstructValuePlaceholder);
Debug.Assert(assignment.Right.Kind == BoundKind.DeconstructValuePlaceholder);
var rewrittenLeft = (BoundExpression)Visit(assignment.Left);
var rewrittenRight = (BoundExpression)Visit(assignment.Right);
var loweredAssignment = MakeAssignmentOperator(assignment.Syntax, rewrittenLeft, rewrittenRight, assignment.Type,
used: true, isChecked: false, isCompoundAssignment: false);
RemovePlaceholderReplacement(assignmentInfo.OutputPlaceholder);
stores.Add(loweredAssignment);
}
}
/// <summary>
/// Makes an expression that constructs the return value for the deconstruction.
/// For d-declarations, that is simply void.
/// For d-assignments, that is a series of tuple constructions, that are chained with the help of placeholders.
/// The placeholders that are set are added to the list for later clearing.
/// </summary>
private BoundExpression MakeReturnValue(BoundDeconstructionAssignmentOperator node, ArrayBuilder<BoundValuePlaceholderBase> placeholders)
{
if (node.IsDeclaration)
{
return new BoundVoid(node.Syntax, node.Type);
}
BoundExpression loweredConstruction = null;
foreach (var constructionInfo in node.ConstructionStepsOpt)
{
// All the input placeholders for the constructions should already be set
loweredConstruction = (BoundExpression)Visit(constructionInfo.Construct);
AddPlaceholderReplacement(constructionInfo.OutputPlaceholder, loweredConstruction);
placeholders.Add(constructionInfo.OutputPlaceholder);
}
Debug.Assert(loweredConstruction != null);
return loweredConstruction;
}
public override BoundNode VisitDeconstructionAssignmentOperator(BoundDeconstructionAssignmentOperator node)
{
// For deconstruction declarations, the BoundLocals in the LeftVariables should not be added to the map
if (!node.IsDeclaration)
{
VisitList(node.LeftVariables);
}
Visit(node.Right);
// don't map the deconstruction, conversion or assignment steps
return null;
}
public override BoundNode VisitDeconstructionAssignmentOperator(BoundDeconstructionAssignmentOperator node)
{
return(this.SetMayHaveSideEffects());
}
public override BoundNode VisitDeconstructionAssignmentOperator(BoundDeconstructionAssignmentOperator node)
{
VisitList(node.LeftVariables);
Visit(node.Right);
// don't map the deconstruction, conversion or assignment steps
return null;
}
