/// <summary>
/// This is the entry point for foreach-loop lowering. It delegates to
/// RewriteEnumeratorForEachStatement
/// RewriteSingleDimensionalArrayForEachStatement
/// RewriteMultiDimensionalArrayForEachStatement
/// RewriteStringForEachStatement
/// </summary>
/// <remarks>
/// We are diverging from the C# 4 spec (and Dev10) to follow the C# 5 spec.
/// The iteration variable will be declared *inside* each loop iteration,
/// rather than outside the loop.
/// </remarks>
public override BoundNode VisitForEachStatement(BoundForEachStatement node)
{
// No point in performing this lowering if the node won't be emitted.
if (node.HasErrors)
{
return node;
}
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
TypeSymbol nodeExpressionType = collectionExpression.Type;
if (nodeExpressionType.Kind == SymbolKind.ArrayType)
{
ArrayTypeSymbol arrayType = (ArrayTypeSymbol)nodeExpressionType;
if (arrayType.IsSZArray)
{
return RewriteSingleDimensionalArrayForEachStatement(node);
}
else
{
return RewriteMultiDimensionalArrayForEachStatement(node);
}
}
else if (nodeExpressionType.SpecialType == SpecialType.System_String)
{
return RewriteStringForEachStatement(node);
}
else
{
return RewriteEnumeratorForEachStatement(node);
}
}
public override BoundNode VisitForEachStatement(BoundForEachStatement node)
{
if (IsInside)
{
_variablesDeclared.Add(node.IterationVariable);
}
return base.VisitForEachStatement(node);
}
public override BoundNode VisitForEachStatement(BoundForEachStatement node)
{
if (IsInside)
{
_labelsInside.Add(node.BreakLabel);
_labelsInside.Add(node.ContinueLabel);
}
return base.VisitForEachStatement(node);
}
private void InstrumentForEachStatement(BoundForEachStatement original, ref BoundStatement result)
{
if (this.Instrument)
{
result = _instrumenter.InstrumentForEachStatement(original, result);
}
}
private void InstrumentForEachStatementCollectionVarDeclaration(BoundForEachStatement original, ref BoundStatement collectionVarDecl)
{
if (this.Instrument)
{
collectionVarDecl = _instrumenter.InstrumentForEachStatementCollectionVarDeclaration(original, collectionVarDecl);
}
}
public virtual BoundStatement InstrumentForEachStatementGotoContinue(BoundForEachStatement original, BoundStatement gotoContinue)
{
Debug.Assert(!original.WasCompilerGenerated);
Debug.Assert(original.Syntax.Kind() == SyntaxKind.ForEachStatement);
return gotoContinue;
}
public override BoundStatement InstrumentForEachStatementGotoEnd(BoundForEachStatement original, BoundStatement gotoEnd)
{
return(Previous.InstrumentForEachStatementGotoEnd(original, gotoEnd));
}
/// <summary>
/// Add sequence point |here|:
///
/// foreach (|Type var| in expr) { }
/// </summary>
/// <remarks>
/// Hit every iteration.
/// </remarks>
public override BoundStatement InstrumentForEachStatementIterationVarDeclaration(BoundForEachStatement original, BoundStatement iterationVarDecl)
{
TextSpan iterationVarDeclSpan;
switch (original.Syntax.Kind())
{
case SyntaxKind.ForEachStatement:
{
var forEachSyntax = (ForEachStatementSyntax)original.Syntax;
iterationVarDeclSpan = TextSpan.FromBounds(forEachSyntax.Type.SpanStart, forEachSyntax.Identifier.Span.End);
break;
}
case SyntaxKind.ForEachComponentStatement:
{
var forEachSyntax = (ForEachComponentStatementSyntax)original.Syntax;
iterationVarDeclSpan = forEachSyntax.VariableComponent.Span;
break;
}
default:
throw ExceptionUtilities.UnexpectedValue(original.Syntax.Kind());
}
return new BoundSequencePointWithSpan(original.Syntax,
base.InstrumentForEachStatementIterationVarDeclaration(original, iterationVarDecl),
iterationVarDeclSpan);
}
public override BoundStatement InstrumentForEachStatementGotoContinue(BoundForEachStatement original, BoundStatement gotoContinue)
{
return(Previous.InstrumentForEachStatementGotoContinue(original, gotoContinue));
}
public override BoundStatement InstrumentForEachStatementCollectionVarDeclaration(BoundForEachStatement original, BoundStatement collectionVarDecl)
{
return Previous.InstrumentForEachStatementCollectionVarDeclaration(original, collectionVarDecl);
}
/// <summary>
/// Add sequence point |here|:
///
/// foreach (|Type var| in expr) { }
/// </summary>
/// <remarks>
/// Hit every iteration.
/// </remarks>
public override BoundStatement InstrumentForEachStatementIterationVarDeclaration(BoundForEachStatement original, BoundStatement iterationVarDecl)
{
TextSpan iterationVarDeclSpan;
switch (original.Syntax.Kind())
{
case SyntaxKind.ForEachStatement:
{
var forEachSyntax = (ForEachStatementSyntax)original.Syntax;
iterationVarDeclSpan = TextSpan.FromBounds(forEachSyntax.Type.SpanStart, forEachSyntax.Identifier.Span.End);
break;
}
case SyntaxKind.ForEachVariableStatement:
{
var forEachSyntax = (ForEachVariableStatementSyntax)original.Syntax;
iterationVarDeclSpan = forEachSyntax.Variable.Span;
break;
}
default:
throw ExceptionUtilities.UnexpectedValue(original.Syntax.Kind());
}
return(new BoundSequencePointWithSpan(original.Syntax,
base.InstrumentForEachStatementIterationVarDeclaration(original, iterationVarDecl),
iterationVarDeclSpan));
}
/// <summary>
/// Add sequence point |here|:
///
/// foreach (Type var in |expr|) { }
/// </summary>
/// <remarks>
/// Hit once, before looping begins.
/// </remarks>
public override BoundStatement InstrumentForEachStatementCollectionVarDeclaration(BoundForEachStatement original, BoundStatement collectionVarDecl)
{
var forEachSyntax = (CommonForEachStatementSyntax)original.Syntax;
return(new BoundSequencePoint(forEachSyntax.Expression,
base.InstrumentForEachStatementCollectionVarDeclaration(original, collectionVarDecl)));
}
/// <summary>
/// Bind the ForEachStatementSyntax at the root of this binder.
/// </summary>
internal override BoundStatement BindForEachParts(DiagnosticBag diagnostics, Binder originalBinder)
{
BoundForEachStatement result = BindForEachPartsWorker(diagnostics, originalBinder);
return(result);
}
public override BoundStatement InstrumentForEachStatement(BoundForEachStatement original, BoundStatement rewritten)
{
return(Previous.InstrumentForEachStatement(original, rewritten));
}
public override BoundStatement InstrumentForEachStatementCollectionVarDeclaration(BoundForEachStatement original, BoundStatement collectionVarDecl)
{
return(Previous.InstrumentForEachStatementCollectionVarDeclaration(original, collectionVarDecl));
}
public override BoundStatement InstrumentForEachStatementDeconstructionVariablesDeclaration(BoundForEachStatement original, BoundStatement iterationVarDecl)
{
return(Previous.InstrumentForEachStatementDeconstructionVariablesDeclaration(original, iterationVarDecl));
}
public override BoundStatement InstrumentForEachStatementGotoEnd(BoundForEachStatement original, BoundStatement gotoEnd)
{
return Previous.InstrumentForEachStatementGotoEnd(original, gotoEnd);
}
public override BoundStatement InstrumentForEachStatementGotoContinue(BoundForEachStatement original, BoundStatement gotoContinue)
{
return Previous.InstrumentForEachStatementGotoContinue(original, gotoContinue);
}
/// <summary>
/// Lower a foreach loop that will enumerate a single-dimensional array.
///
/// A[] a = x;
/// for (int p = 0; p < a.Length; p = p + 1) {
/// V v = (V)a[p];
/// // body
/// }
/// </summary>
/// <remarks>
/// We will follow Dev10 in diverging from the C# 4 spec by ignoring Array's
/// implementation of IEnumerable and just indexing into its elements.
///
/// NOTE: We're assuming that sequence points have already been generated.
/// Otherwise, lowering to for-loops would generated spurious ones.
/// </remarks>
private BoundStatement RewriteSingleDimensionalArrayForEachStatement(BoundForEachStatement node)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)node.Syntax;
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
Debug.Assert(collectionExpression.Type.IsArray());
ArrayTypeSymbol arrayType = (ArrayTypeSymbol)collectionExpression.Type;
Debug.Assert(arrayType.IsSZArray);
TypeSymbol intType = _compilation.GetSpecialType(SpecialType.System_Int32);
TypeSymbol boolType = _compilation.GetSpecialType(SpecialType.System_Boolean);
BoundExpression rewrittenExpression = (BoundExpression)Visit(collectionExpression);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
// A[] a
LocalSymbol arrayVar = _factory.SynthesizedLocal(arrayType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArray);
// A[] a = /*node.Expression*/;
BoundStatement arrayVarDecl = MakeLocalDeclaration(forEachSyntax, arrayVar, rewrittenExpression);
AddForEachExpressionSequencePoint(forEachSyntax, ref arrayVarDecl);
// Reference to a.
BoundLocal boundArrayVar = MakeBoundLocal(forEachSyntax, arrayVar, arrayType);
// int p
LocalSymbol positionVar = _factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayIndex);
// Reference to p.
BoundLocal boundPositionVar = MakeBoundLocal(forEachSyntax, positionVar, intType);
// int p = 0;
BoundStatement positionVarDecl = MakeLocalDeclaration(forEachSyntax, positionVar,
MakeLiteral(forEachSyntax, ConstantValue.Default(SpecialType.System_Int32), intType));
// V v
LocalSymbol iterationVar = node.IterationVariable;
TypeSymbol iterationVarType = iterationVar.Type;
// (V)a[p]
BoundExpression iterationVarInitValue = MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: new BoundArrayAccess(
syntax: forEachSyntax,
expression: boundArrayVar,
indices: ImmutableArray.Create<BoundExpression>(boundPositionVar),
type: arrayType.ElementType),
conversion: node.ElementConversion,
rewrittenType: iterationVarType,
@checked: node.Checked);
// V v = (V)a[p];
BoundStatement iterationVariableDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarInitValue);
AddForEachIterationVariableSequencePoint(forEachSyntax, ref iterationVariableDecl);
BoundStatement initializer = new BoundStatementList(forEachSyntax,
statements: ImmutableArray.Create<BoundStatement>(arrayVarDecl, positionVarDecl));
// a.Length
BoundExpression arrayLength = new BoundArrayLength(
syntax: forEachSyntax,
expression: boundArrayVar,
type: intType);
// p < a.Length
BoundExpression exitCondition = new BoundBinaryOperator(
syntax: forEachSyntax,
operatorKind: BinaryOperatorKind.IntLessThan,
left: boundPositionVar,
right: arrayLength,
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: boolType);
// p = p + 1;
BoundStatement positionIncrement = MakePositionIncrement(forEachSyntax, boundPositionVar, intType);
// { V v = (V)a[p]; /* node.Body */ }
BoundStatement loopBody = CreateBlockDeclaringIterationVariable(iterationVar, iterationVariableDecl, rewrittenBody, forEachSyntax);
// for (A[] a = /*node.Expression*/, int p = 0; p < a.Length; p = p + 1) {
// V v = (V)a[p];
// /*node.Body*/
// }
BoundStatement result = RewriteForStatement(
syntax: node.Syntax,
outerLocals: ImmutableArray.Create<LocalSymbol>(arrayVar, positionVar),
rewrittenInitializer: initializer,
rewrittenCondition: exitCondition,
conditionSyntaxOpt: null,
conditionSpanOpt: forEachSyntax.InKeyword.Span,
rewrittenIncrement: positionIncrement,
rewrittenBody: loopBody,
breakLabel: node.BreakLabel,
continueLabel: node.ContinueLabel,
hasErrors: node.HasErrors);
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return result;
}
/// <summary>
/// Add sequence point |here|:
///
/// foreach (Type var in |expr|) { }
/// </summary>
/// <remarks>
/// Hit once, before looping begins.
/// </remarks>
public override BoundStatement InstrumentForEachStatementCollectionVarDeclaration(BoundForEachStatement original, BoundStatement collectionVarDecl)
{
// NOTE: This is slightly different from Dev10. In Dev10, when you stop the debugger
// on the collection expression, you can see the (uninitialized) iteration variable.
// In Roslyn, you cannot because the iteration variable is re-declared in each iteration
// of the loop and is, therefore, not yet in scope.
return(new BoundSequencePoint(((ForEachStatementSyntax)original.Syntax).Expression,
base.InstrumentForEachStatementCollectionVarDeclaration(original, collectionVarDecl)));
}
public override BoundStatement InstrumentForEachStatementConditionalGotoStart(BoundForEachStatement original, BoundStatement branchBack)
{
return(Previous.InstrumentForEachStatementConditionalGotoStart(original, branchBack));
}
/// <summary>
/// Lower a foreach loop that will enumerate a collection using an enumerator.
///
/// E e = ((C)(x)).GetEnumerator()
/// try {
/// while (e.MoveNext()) {
/// V v = (V)(T)e.Current;
/// // body
/// }
/// }
/// finally {
/// // clean up e
/// }
/// </summary>
private BoundStatement RewriteEnumeratorForEachStatement(BoundForEachStatement node)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)node.Syntax;
ForEachEnumeratorInfo enumeratorInfo = node.EnumeratorInfoOpt;
Debug.Assert(enumeratorInfo != null);
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
BoundExpression rewrittenExpression = (BoundExpression)Visit(collectionExpression);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
TypeSymbol enumeratorType = enumeratorInfo.GetEnumeratorMethod.ReturnType;
TypeSymbol elementType = enumeratorInfo.ElementType;
// E e
LocalSymbol enumeratorVar = _factory.SynthesizedLocal(enumeratorType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachEnumerator);
// Reference to e.
BoundLocal boundEnumeratorVar = MakeBoundLocal(forEachSyntax, enumeratorVar, enumeratorType);
// ((C)(x)).GetEnumerator() or (x).GetEnumerator();
BoundExpression enumeratorVarInitValue = SynthesizeCall(forEachSyntax, rewrittenExpression, enumeratorInfo.GetEnumeratorMethod, enumeratorInfo.CollectionConversion, enumeratorInfo.CollectionType);
// E e = ((C)(x)).GetEnumerator();
BoundStatement enumeratorVarDecl = MakeLocalDeclaration(forEachSyntax, enumeratorVar, enumeratorVarInitValue);
AddForEachExpressionSequencePoint(forEachSyntax, ref enumeratorVarDecl);
// V v
LocalSymbol iterationVar = node.IterationVariable;
//(V)(T)e.Current
BoundExpression iterationVarAssignValue = MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundEnumeratorVar,
method: enumeratorInfo.CurrentPropertyGetter),
conversion: enumeratorInfo.CurrentConversion,
rewrittenType: elementType,
@checked: node.Checked),
conversion: node.ElementConversion,
rewrittenType: iterationVar.Type,
@checked: node.Checked);
// V v = (V)(T)e.Current;
BoundStatement iterationVarDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarAssignValue);
AddForEachIterationVariableSequencePoint(forEachSyntax, ref iterationVarDecl);
// while (e.MoveNext()) {
// V v = (V)(T)e.Current;
// /* node.Body */
// }
var rewrittenBodyBlock = CreateBlockDeclaringIterationVariable(iterationVar, iterationVarDecl, rewrittenBody, forEachSyntax);
BoundStatement whileLoop = RewriteWhileStatement(
syntax: forEachSyntax,
rewrittenCondition: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundEnumeratorVar,
method: enumeratorInfo.MoveNextMethod),
conditionSequencePointSpan: forEachSyntax.InKeyword.Span,
rewrittenBody: rewrittenBodyBlock,
breakLabel: node.BreakLabel,
continueLabel: node.ContinueLabel,
hasErrors: false);
BoundStatement result;
MethodSymbol disposeMethod;
if (enumeratorInfo.NeedsDisposeMethod && Binder.TryGetSpecialTypeMember(_compilation, SpecialMember.System_IDisposable__Dispose, forEachSyntax, _diagnostics, out disposeMethod))
{
Binder.ReportDiagnosticsIfObsolete(_diagnostics, disposeMethod, forEachSyntax,
hasBaseReceiver: false,
containingMember: _factory.CurrentMethod,
containingType: _factory.CurrentType,
location: enumeratorInfo.Location);
BoundBlock finallyBlockOpt;
var idisposableTypeSymbol = disposeMethod.ContainingType;
var conversions = new TypeConversions(_factory.CurrentMethod.ContainingAssembly.CorLibrary);
HashSet<DiagnosticInfo> useSiteDiagnostics = null;
var isImplicit = conversions.ClassifyImplicitConversion(enumeratorType, idisposableTypeSymbol, ref useSiteDiagnostics).IsImplicit;
_diagnostics.Add(forEachSyntax, useSiteDiagnostics);
if (isImplicit)
{
Debug.Assert(enumeratorInfo.NeedsDisposeMethod);
Conversion receiverConversion = enumeratorType.IsStructType() ?
Conversion.Boxing :
Conversion.ImplicitReference;
// ((IDisposable)e).Dispose(); or e.Dispose();
BoundStatement disposeCall = new BoundExpressionStatement(forEachSyntax,
expression: SynthesizeCall(forEachSyntax, boundEnumeratorVar, disposeMethod, receiverConversion, idisposableTypeSymbol));
BoundStatement disposeStmt;
if (enumeratorType.IsValueType)
{
// No way for the struct to be nullable and disposable.
Debug.Assert(((TypeSymbol)enumeratorType.OriginalDefinition).SpecialType != SpecialType.System_Nullable_T);
// For non-nullable structs, no null check is required.
disposeStmt = disposeCall;
}
else
{
// NB: cast to object missing from spec. Needed to ignore user-defined operators and box type parameters.
// if ((object)e != null) ((IDisposable)e).Dispose();
disposeStmt = RewriteIfStatement(
syntax: forEachSyntax,
rewrittenCondition: new BoundBinaryOperator(forEachSyntax,
operatorKind: BinaryOperatorKind.NotEqual,
left: MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: boundEnumeratorVar,
conversion: enumeratorInfo.EnumeratorConversion,
rewrittenType: _compilation.GetSpecialType(SpecialType.System_Object),
@checked: false),
right: MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Null,
type: null),
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: _compilation.GetSpecialType(SpecialType.System_Boolean)),
rewrittenConsequence: disposeCall,
rewrittenAlternativeOpt: null,
hasErrors: false);
}
finallyBlockOpt = new BoundBlock(forEachSyntax,
locals: ImmutableArray<LocalSymbol>.Empty,
localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
statements: ImmutableArray.Create<BoundStatement>(disposeStmt));
}
else
{
Debug.Assert(!enumeratorType.IsSealed);
// IDisposable d
LocalSymbol disposableVar = _factory.SynthesizedLocal(idisposableTypeSymbol);
// Reference to d.
BoundLocal boundDisposableVar = MakeBoundLocal(forEachSyntax, disposableVar, idisposableTypeSymbol);
BoundTypeExpression boundIDisposableTypeExpr = new BoundTypeExpression(forEachSyntax,
aliasOpt: null,
type: idisposableTypeSymbol);
// e as IDisposable
BoundExpression disposableVarInitValue = new BoundAsOperator(forEachSyntax,
operand: boundEnumeratorVar,
targetType: boundIDisposableTypeExpr,
conversion: Conversion.ExplicitReference, // Explicit so the emitter won't optimize it away.
type: idisposableTypeSymbol);
// IDisposable d = e as IDisposable;
BoundStatement disposableVarDecl = MakeLocalDeclaration(forEachSyntax, disposableVar, disposableVarInitValue);
// if (d != null) d.Dispose();
BoundStatement ifStmt = RewriteIfStatement(
syntax: forEachSyntax,
rewrittenCondition: new BoundBinaryOperator(forEachSyntax,
operatorKind: BinaryOperatorKind.NotEqual, // reference equality
left: boundDisposableVar,
right: MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Null,
type: null),
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: _compilation.GetSpecialType(SpecialType.System_Boolean)),
rewrittenConsequence: new BoundExpressionStatement(forEachSyntax,
expression: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundDisposableVar,
method: disposeMethod)),
rewrittenAlternativeOpt: null,
hasErrors: false);
// IDisposable d = e as IDisposable;
// if (d != null) d.Dispose();
finallyBlockOpt = new BoundBlock(forEachSyntax,
locals: ImmutableArray.Create<LocalSymbol>(disposableVar),
localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
statements: ImmutableArray.Create<BoundStatement>(disposableVarDecl, ifStmt));
}
// try {
// while (e.MoveNext()) {
// V v = (V)(T)e.Current;
// /* loop body */
// }
// }
// finally {
// /* dispose of e */
// }
BoundStatement tryFinally = new BoundTryStatement(forEachSyntax,
tryBlock: new BoundBlock(forEachSyntax,
locals: ImmutableArray<LocalSymbol>.Empty,
localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
statements: ImmutableArray.Create<BoundStatement>(whileLoop)),
catchBlocks: ImmutableArray<BoundCatchBlock>.Empty,
finallyBlockOpt: finallyBlockOpt);
// E e = ((C)(x)).GetEnumerator();
// try {
// /* as above */
result = new BoundBlock(
syntax: forEachSyntax,
locals: ImmutableArray.Create(enumeratorVar),
localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
statements: ImmutableArray.Create<BoundStatement>(enumeratorVarDecl, tryFinally));
}
else
{
// E e = ((C)(x)).GetEnumerator();
// while (e.MoveNext()) {
// V v = (V)(T)e.Current;
// /* loop body */
// }
result = new BoundBlock(
syntax: forEachSyntax,
locals: ImmutableArray.Create(enumeratorVar),
localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
statements: ImmutableArray.Create<BoundStatement>(enumeratorVarDecl, whileLoop));
}
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return result;
}
public override BoundStatement InstrumentForEachStatementDeconstructionVariablesDeclaration(BoundForEachStatement original, BoundStatement iterationVarDecl)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)original.Syntax;
return(new BoundSequencePointWithSpan(forEachSyntax, base.InstrumentForEachStatementDeconstructionVariablesDeclaration(original, iterationVarDecl), forEachSyntax.DeconstructionVariables.Span));
}
public override BoundStatement InstrumentForEachStatementDeconstructionVariablesDeclaration(BoundForEachStatement original, BoundStatement iterationVarDecl)
{
var forEachSyntax = (ForEachComponentStatementSyntax)original.Syntax;
return new BoundSequencePointWithSpan(forEachSyntax, base.InstrumentForEachStatementDeconstructionVariablesDeclaration(original, iterationVarDecl), forEachSyntax.VariableComponent.Span);
}
/// <summary>
/// Add sequence point |here|:
///
/// foreach (|Type var| in expr) { }
/// </summary>
/// <remarks>
/// Hit every iteration.
/// </remarks>
public override BoundStatement InstrumentForEachStatementIterationVarDeclaration(BoundForEachStatement original, BoundStatement iterationVarDecl)
{
var forEachSyntax = (ForEachStatementSyntax)original.Syntax;
TextSpan iterationVarDeclSpan = TextSpan.FromBounds(forEachSyntax.Type.SpanStart, forEachSyntax.Identifier.Span.End);
return(new BoundSequencePointWithSpan(forEachSyntax,
base.InstrumentForEachStatementIterationVarDeclaration(original, iterationVarDecl),
iterationVarDeclSpan));
}
public override BoundStatement InstrumentForEachStatementConditionalGotoStart(BoundForEachStatement original, BoundStatement branchBack)
{
var syntax = (CommonForEachStatementSyntax)original.Syntax;
return new BoundSequencePointWithSpan(syntax,
base.InstrumentForEachStatementConditionalGotoStart(original, branchBack),
syntax.InKeyword.Span);
}
public override BoundStatement InstrumentForEachStatementGotoEnd(BoundForEachStatement original, BoundStatement gotoEnd)
{
return(ForStatementCreateGotoEndSequencePoint(base.InstrumentForEachStatementGotoEnd(original, gotoEnd)));
}
public virtual BoundStatement InstrumentForEachStatementConditionalGotoStart(BoundForEachStatement original, BoundStatement branchBack)
{
Debug.Assert(!original.WasCompilerGenerated);
Debug.Assert(original.Syntax.Kind() == SyntaxKind.ForEachStatement);
return branchBack;
}
public override BoundStatement InstrumentForEachStatementConditionalGotoStart(BoundForEachStatement original, BoundStatement branchBack)
{
var syntax = (ForEachStatementSyntax)original.Syntax;
return(new BoundSequencePointWithSpan(syntax,
base.InstrumentForEachStatementConditionalGotoStart(original, branchBack),
syntax.InKeyword.Span));
}
/// <summary>
/// Takes the expression for the current value of the iteration variable and either
/// (1) assigns it into a local, or
/// (2) deconstructs it into multiple locals (if there is a deconstruct step).
///
/// Produces `V v = /* expression */` or `(D1 d1, ...) = /* expression */`.
/// </summary>
private BoundStatement LocalOrDeconstructionDeclaration(
BoundForEachStatement forEachBound,
LocalSymbol iterationVar,
BoundExpression iterationVarValue,
out ImmutableArray<LocalSymbol> iterationVariables)
{
var forEachSyntax = (CommonForEachStatementSyntax)forEachBound.Syntax;
BoundStatement iterationVarDecl;
BoundForEachDeconstructStep deconstruction = forEachBound.DeconstructionOpt;
if (deconstruction == null)
{
// V v = /* expression */
iterationVarDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarValue);
iterationVariables = ImmutableArray.Create(iterationVar);
}
else
{
// (D1 d1, ...) = /* expression */
var assignment = deconstruction.DeconstructionAssignment;
AddPlaceholderReplacement(deconstruction.TargetPlaceholder, iterationVarValue);
BoundExpression loweredAssignment = VisitExpression(assignment);
iterationVarDecl = new BoundExpressionStatement(assignment.Syntax, loweredAssignment);
RemovePlaceholderReplacement(deconstruction.TargetPlaceholder);
iterationVariables = assignment.LeftVariables.SelectAsArray(v => ((BoundLocal)v).LocalSymbol);
}
return iterationVarDecl;
}
public override BoundStatement InstrumentForEachStatementGotoContinue(BoundForEachStatement original, BoundStatement gotoContinue)
{
return(new BoundSequencePoint(null, base.InstrumentForEachStatementGotoContinue(original, gotoContinue)));
}
private void InstrumentForEachStatementIterationVarDeclaration(BoundForEachStatement original, ref BoundStatement iterationVarDecl)
{
if (this.Instrument)
{
CommonForEachStatementSyntax forEachSyntax = (CommonForEachStatementSyntax)original.Syntax;
if (forEachSyntax is ForEachComponentStatementSyntax)
{
iterationVarDecl = _instrumenter.InstrumentForEachStatementDeconstructionVariablesDeclaration(original, iterationVarDecl);
}
else
{
iterationVarDecl = _instrumenter.InstrumentForEachStatementIterationVarDeclaration(original, iterationVarDecl);
}
}
}
/// <summary>
/// Lower a foreach loop that will enumerate the characters of a string.
///
/// string s = x;
/// for (int p = 0; p < s.Length; p = p + 1) {
/// V v = (V)s.Chars[p];
/// // body
/// }
/// </summary>
/// <remarks>
/// We will follow Dev10 in diverging from the C# 4 spec by ignoring string's
/// implementation of IEnumerable and just indexing into its characters.
///
/// NOTE: We're assuming that sequence points have already been generated.
/// Otherwise, lowering to for-loops would generated spurious ones.
/// </remarks>
private BoundStatement RewriteStringForEachStatement(BoundForEachStatement node)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)node.Syntax;
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
TypeSymbol stringType = collectionExpression.Type;
Debug.Assert(stringType.SpecialType == SpecialType.System_String);
TypeSymbol intType = _compilation.GetSpecialType(SpecialType.System_Int32);
TypeSymbol boolType = _compilation.GetSpecialType(SpecialType.System_Boolean);
BoundExpression rewrittenExpression = (BoundExpression)Visit(collectionExpression);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
// string s;
LocalSymbol stringVar = _factory.SynthesizedLocal(stringType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArray);
// int p;
LocalSymbol positionVar = _factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayIndex);
// Reference to s.
BoundLocal boundStringVar = MakeBoundLocal(forEachSyntax, stringVar, stringType);
// Reference to p.
BoundLocal boundPositionVar = MakeBoundLocal(forEachSyntax, positionVar, intType);
// string s = /*expr*/;
BoundStatement stringVarDecl = MakeLocalDeclaration(forEachSyntax, stringVar, rewrittenExpression);
AddForEachExpressionSequencePoint(forEachSyntax, ref stringVarDecl);
// int p = 0;
BoundStatement positionVariableDecl = MakeLocalDeclaration(forEachSyntax, positionVar,
MakeLiteral(forEachSyntax, ConstantValue.Default(SpecialType.System_Int32), intType));
// string s = /*node.Expression*/; int p = 0;
BoundStatement initializer = new BoundStatementList(forEachSyntax,
statements: ImmutableArray.Create <BoundStatement>(stringVarDecl, positionVariableDecl));
MethodSymbol method = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_String__Length);
BoundExpression stringLength = BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundStringVar,
method: method,
arguments: ImmutableArray <BoundExpression> .Empty);
// p < s.Length
BoundExpression exitCondition = new BoundBinaryOperator(
syntax: forEachSyntax,
operatorKind: BinaryOperatorKind.IntLessThan,
left: boundPositionVar,
right: stringLength,
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: boolType);
// p = p + 1;
BoundStatement positionIncrement = MakePositionIncrement(forEachSyntax, boundPositionVar, intType);
LocalSymbol iterationVar = node.IterationVariable;
TypeSymbol iterationVarType = iterationVar.Type;
Debug.Assert(node.ElementConversion.IsValid);
// (V)s.Chars[p]
MethodSymbol chars = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_String__Chars);
BoundExpression iterationVarInitValue = MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundStringVar,
method: chars,
arguments: ImmutableArray.Create <BoundExpression>(boundPositionVar)),
conversion: node.ElementConversion,
rewrittenType: iterationVarType,
@checked: node.Checked);
// V v = (V)s.Chars[p];
BoundStatement iterationVarDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarInitValue);
AddForEachIterationVariableSequencePoint(forEachSyntax, ref iterationVarDecl);
// { V v = (V)s.Chars[p]; /*node.Body*/ }
BoundStatement loopBody = CreateBlockDeclaringIterationVariable(iterationVar, iterationVarDecl, rewrittenBody, forEachSyntax);
// for (string s = /*node.Expression*/, int p = 0; p < s.Length; p = p + 1) {
// V v = (V)s.Chars[p];
// /*node.Body*/
// }
BoundStatement result = RewriteForStatement(
syntax: forEachSyntax,
outerLocals: ImmutableArray.Create(stringVar, positionVar),
rewrittenInitializer: initializer,
rewrittenCondition: exitCondition,
conditionSyntaxOpt: null,
conditionSpanOpt: forEachSyntax.InKeyword.Span,
rewrittenIncrement: positionIncrement,
rewrittenBody: loopBody,
breakLabel: node.BreakLabel,
continueLabel: node.ContinueLabel,
hasErrors: node.HasErrors);
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return(result);
}
public override void VisitForEachIterationVariable(BoundForEachStatement node)
{
var local = node.IterationVariable;
if ((object)local != null)
{
GetOrCreateSlot(local);
Assign(node, value: null);
}
}
/// <summary>
/// Lower a foreach loop that will enumerate a single-dimensional array.
///
/// A[] a = x;
/// for (int p = 0; p < a.Length; p = p + 1) {
/// V v = (V)a[p];
/// // body
/// }
/// </summary>
/// <remarks>
/// We will follow Dev10 in diverging from the C# 4 spec by ignoring Array's
/// implementation of IEnumerable and just indexing into its elements.
///
/// NOTE: We're assuming that sequence points have already been generated.
/// Otherwise, lowering to for-loops would generated spurious ones.
/// </remarks>
private BoundStatement RewriteSingleDimensionalArrayForEachStatement(BoundForEachStatement node)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)node.Syntax;
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
Debug.Assert(collectionExpression.Type.IsArray());
ArrayTypeSymbol arrayType = (ArrayTypeSymbol)collectionExpression.Type;
Debug.Assert(arrayType.Rank == 1);
TypeSymbol intType = _compilation.GetSpecialType(SpecialType.System_Int32);
TypeSymbol boolType = _compilation.GetSpecialType(SpecialType.System_Boolean);
BoundExpression rewrittenExpression = (BoundExpression)Visit(collectionExpression);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
// A[] a
LocalSymbol arrayVar = _factory.SynthesizedLocal(arrayType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArray);
// A[] a = /*node.Expression*/;
BoundStatement arrayVarDecl = MakeLocalDeclaration(forEachSyntax, arrayVar, rewrittenExpression);
AddForEachExpressionSequencePoint(forEachSyntax, ref arrayVarDecl);
// Reference to a.
BoundLocal boundArrayVar = MakeBoundLocal(forEachSyntax, arrayVar, arrayType);
// int p
LocalSymbol positionVar = _factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayIndex);
// Reference to p.
BoundLocal boundPositionVar = MakeBoundLocal(forEachSyntax, positionVar, intType);
// int p = 0;
BoundStatement positionVarDecl = MakeLocalDeclaration(forEachSyntax, positionVar,
MakeLiteral(forEachSyntax, ConstantValue.Default(SpecialType.System_Int32), intType));
// V v
LocalSymbol iterationVar = node.IterationVariable;
TypeSymbol iterationVarType = iterationVar.Type;
// (V)a[p]
BoundExpression iterationVarInitValue = MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: new BoundArrayAccess(
syntax: forEachSyntax,
expression: boundArrayVar,
indices: ImmutableArray.Create <BoundExpression>(boundPositionVar),
type: arrayType.ElementType),
conversion: node.ElementConversion,
rewrittenType: iterationVarType,
@checked: node.Checked);
// V v = (V)a[p];
BoundStatement iterationVariableDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarInitValue);
AddForEachIterationVariableSequencePoint(forEachSyntax, ref iterationVariableDecl);
BoundStatement initializer = new BoundStatementList(forEachSyntax,
statements: ImmutableArray.Create <BoundStatement>(arrayVarDecl, positionVarDecl));
// a.Length
BoundExpression arrayLength = new BoundArrayLength(
syntax: forEachSyntax,
expression: boundArrayVar,
type: intType);
// p < a.Length
BoundExpression exitCondition = new BoundBinaryOperator(
syntax: forEachSyntax,
operatorKind: BinaryOperatorKind.IntLessThan,
left: boundPositionVar,
right: arrayLength,
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: boolType);
// p = p + 1;
BoundStatement positionIncrement = MakePositionIncrement(forEachSyntax, boundPositionVar, intType);
// { V v = (V)a[p]; /* node.Body */ }
BoundStatement loopBody = CreateBlockDeclaringIterationVariable(iterationVar, iterationVariableDecl, rewrittenBody, forEachSyntax);
// for (A[] a = /*node.Expression*/, int p = 0; p < a.Length; p = p + 1) {
// V v = (V)a[p];
// /*node.Body*/
// }
BoundStatement result = RewriteForStatement(
syntax: node.Syntax,
outerLocals: ImmutableArray.Create <LocalSymbol>(arrayVar, positionVar),
rewrittenInitializer: initializer,
rewrittenCondition: exitCondition,
conditionSyntaxOpt: null,
conditionSpanOpt: forEachSyntax.InKeyword.Span,
rewrittenIncrement: positionIncrement,
rewrittenBody: loopBody,
breakLabel: node.BreakLabel,
continueLabel: node.ContinueLabel,
hasErrors: node.HasErrors);
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return(result);
}
public override BoundStatement InstrumentForEachStatementConditionalGotoStart(BoundForEachStatement original, BoundStatement branchBack)
{
return Previous.InstrumentForEachStatementConditionalGotoStart(original, branchBack);
}
/// <summary>
/// Lower a foreach loop that will enumerate a multi-dimensional array.
///
/// A[...] a = x;
/// int q_0 = a.GetUpperBound(0), q_1 = a.GetUpperBound(1), ...;
/// for (int p_0 = a.GetLowerBound(0); p_0 <= q_0; p_0 = p_0 + 1)
/// for (int p_1 = a.GetLowerBound(1); p_1 <= q_1; p_1 = p_1 + 1)
/// ...
/// { V v = (V)a[p_0, p_1, ...]; /* body */ }
/// </summary>
/// <remarks>
/// We will follow Dev10 in diverging from the C# 4 spec by ignoring Array's
/// implementation of IEnumerable and just indexing into its elements.
///
/// NOTE: We're assuming that sequence points have already been generated.
/// Otherwise, lowering to nested for-loops would generated spurious ones.
/// </remarks>
private BoundStatement RewriteMultiDimensionalArrayForEachStatement(BoundForEachStatement node)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)node.Syntax;
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
Debug.Assert(collectionExpression.Type.IsArray());
ArrayTypeSymbol arrayType = (ArrayTypeSymbol)collectionExpression.Type;
int rank = arrayType.Rank;
Debug.Assert(rank > 1);
TypeSymbol intType = _compilation.GetSpecialType(SpecialType.System_Int32);
TypeSymbol boolType = _compilation.GetSpecialType(SpecialType.System_Boolean);
// Values we'll use every iteration
MethodSymbol getLowerBoundMethod = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_Array__GetLowerBound);
MethodSymbol getUpperBoundMethod = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_Array__GetUpperBound);
BoundExpression rewrittenExpression = (BoundExpression)Visit(collectionExpression);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
// A[...] a
LocalSymbol arrayVar = _factory.SynthesizedLocal(arrayType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArray);
BoundLocal boundArrayVar = MakeBoundLocal(forEachSyntax, arrayVar, arrayType);
// A[...] a = /*node.Expression*/;
BoundStatement arrayVarDecl = MakeLocalDeclaration(forEachSyntax, arrayVar, rewrittenExpression);
AddForEachExpressionSequencePoint(forEachSyntax, ref arrayVarDecl);
// NOTE: dev10 initializes all of the upper bound temps before entering the loop (as opposed to
// initializing each one at the corresponding level of nesting). Doing it at the same time as
// the lower bound would make this code a bit simpler, but it would make it harder to compare
// the roslyn and dev10 IL.
// int q_0, q_1, ...
LocalSymbol[] upperVar = new LocalSymbol[rank];
BoundLocal[] boundUpperVar = new BoundLocal[rank];
BoundStatement[] upperVarDecl = new BoundStatement[rank];
for (int dimension = 0; dimension < rank; dimension++)
{
// int q_dimension
upperVar[dimension] = _factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayLimit);
boundUpperVar[dimension] = MakeBoundLocal(forEachSyntax, upperVar[dimension], intType);
ImmutableArray <BoundExpression> dimensionArgument = ImmutableArray.Create(
MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Create(dimension, ConstantValueTypeDiscriminator.Int32),
type: intType));
// a.GetUpperBound(dimension)
BoundExpression currentDimensionUpperBound = BoundCall.Synthesized(forEachSyntax, boundArrayVar, getUpperBoundMethod, dimensionArgument);
// int q_dimension = a.GetUpperBound(dimension);
upperVarDecl[dimension] = MakeLocalDeclaration(forEachSyntax, upperVar[dimension], currentDimensionUpperBound);
}
// int p_0, p_1, ...
LocalSymbol[] positionVar = new LocalSymbol[rank];
BoundLocal[] boundPositionVar = new BoundLocal[rank];
for (int dimension = 0; dimension < rank; dimension++)
{
positionVar[dimension] = _factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayIndex);
boundPositionVar[dimension] = MakeBoundLocal(forEachSyntax, positionVar[dimension], intType);
}
// V v
LocalSymbol iterationVar = node.IterationVariable;
TypeSymbol iterationVarType = iterationVar.Type;
// (V)a[p_0, p_1, ...]
BoundExpression iterationVarInitValue = MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: new BoundArrayAccess(forEachSyntax,
expression: boundArrayVar,
indices: ImmutableArray.Create((BoundExpression[])boundPositionVar),
type: arrayType.ElementType),
conversion: node.ElementConversion,
rewrittenType: iterationVarType,
@checked: node.Checked);
// V v = (V)a[p_0, p_1, ...];
BoundStatement iterationVarDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarInitValue);
AddForEachIterationVariableSequencePoint(forEachSyntax, ref iterationVarDecl);
// { V v = (V)a[p_0, p_1, ...]; /* node.Body */ }
BoundStatement innermostLoopBody = CreateBlockDeclaringIterationVariable(iterationVar, iterationVarDecl, rewrittenBody, forEachSyntax);
// work from most-nested to least-nested
// for (int p_0 = a.GetLowerBound(0); p_0 <= q_0; p_0 = p_0 + 1)
// for (int p_1 = a.GetLowerBound(0); p_1 <= q_1; p_1 = p_1 + 1)
// ...
// { V v = (V)a[p_0, p_1, ...]; /* node.Body */ }
BoundStatement forLoop = null;
for (int dimension = rank - 1; dimension >= 0; dimension--)
{
ImmutableArray <BoundExpression> dimensionArgument = ImmutableArray.Create(
MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Create(dimension, ConstantValueTypeDiscriminator.Int32),
type: intType));
// a.GetLowerBound(dimension)
BoundExpression currentDimensionLowerBound = BoundCall.Synthesized(forEachSyntax, boundArrayVar, getLowerBoundMethod, dimensionArgument);
// int p_dimension = a.GetLowerBound(dimension);
BoundStatement positionVarDecl = MakeLocalDeclaration(forEachSyntax, positionVar[dimension], currentDimensionLowerBound);
GeneratedLabelSymbol breakLabel = dimension == 0 // outermost for-loop
? node.BreakLabel // i.e. the one that break statements will jump to
: new GeneratedLabelSymbol("break"); // Should not affect emitted code since unused
// p_dimension <= q_dimension //NB: OrEqual
BoundExpression exitCondition = new BoundBinaryOperator(
syntax: forEachSyntax,
operatorKind: BinaryOperatorKind.IntLessThanOrEqual,
left: boundPositionVar[dimension],
right: boundUpperVar[dimension],
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: boolType);
// p_dimension = p_dimension + 1;
BoundStatement positionIncrement = MakePositionIncrement(forEachSyntax, boundPositionVar[dimension], intType);
BoundStatement body;
GeneratedLabelSymbol continueLabel;
if (forLoop == null)
{
// innermost for-loop
body = innermostLoopBody;
continueLabel = node.ContinueLabel; //i.e. the one continue statements will actually jump to
}
else
{
body = forLoop;
continueLabel = new GeneratedLabelSymbol("continue"); // Should not affect emitted code since unused
}
forLoop = RewriteForStatement(
syntax: forEachSyntax,
outerLocals: ImmutableArray.Create(positionVar[dimension]),
rewrittenInitializer: positionVarDecl,
rewrittenCondition: exitCondition,
conditionSyntaxOpt: null,
conditionSpanOpt: forEachSyntax.InKeyword.Span,
rewrittenIncrement: positionIncrement,
rewrittenBody: body,
breakLabel: breakLabel,
continueLabel: continueLabel,
hasErrors: node.HasErrors);
}
Debug.Assert(forLoop != null);
BoundStatement result = new BoundBlock(
forEachSyntax,
ImmutableArray.Create(arrayVar).Concat(upperVar.AsImmutableOrNull()),
ImmutableArray.Create(arrayVarDecl).Concat(upperVarDecl.AsImmutableOrNull()).Add(forLoop));
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return(result);
}
public override BoundStatement InstrumentForEachStatementDeconstructionVariablesDeclaration(BoundForEachStatement original, BoundStatement iterationVarDecl)
{
return Previous.InstrumentForEachStatementDeconstructionVariablesDeclaration(original, iterationVarDecl);
}
/// <summary>
/// Lower a foreach loop that will enumerate a collection using an enumerator.
///
/// E e = ((C)(x)).GetEnumerator()
/// try {
/// while (e.MoveNext()) {
/// V v = (V)(T)e.Current;
/// // body
/// }
/// }
/// finally {
/// // clean up e
/// }
/// </summary>
private BoundStatement RewriteEnumeratorForEachStatement(BoundForEachStatement node)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)node.Syntax;
ForEachEnumeratorInfo enumeratorInfo = node.EnumeratorInfoOpt;
Debug.Assert(enumeratorInfo != null);
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
BoundExpression rewrittenExpression = (BoundExpression)Visit(collectionExpression);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
TypeSymbol enumeratorType = enumeratorInfo.GetEnumeratorMethod.ReturnType;
TypeSymbol elementType = enumeratorInfo.ElementType;
// E e
LocalSymbol enumeratorVar = _factory.SynthesizedLocal(enumeratorType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachEnumerator);
// Reference to e.
BoundLocal boundEnumeratorVar = MakeBoundLocal(forEachSyntax, enumeratorVar, enumeratorType);
// ((C)(x)).GetEnumerator() or (x).GetEnumerator();
BoundExpression enumeratorVarInitValue = SynthesizeCall(forEachSyntax, rewrittenExpression, enumeratorInfo.GetEnumeratorMethod, enumeratorInfo.CollectionConversion, enumeratorInfo.CollectionType);
// E e = ((C)(x)).GetEnumerator();
BoundStatement enumeratorVarDecl = MakeLocalDeclaration(forEachSyntax, enumeratorVar, enumeratorVarInitValue);
AddForEachExpressionSequencePoint(forEachSyntax, ref enumeratorVarDecl);
// V v
LocalSymbol iterationVar = node.IterationVariable;
//(V)(T)e.Current
BoundExpression iterationVarAssignValue = MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundEnumeratorVar,
method: enumeratorInfo.CurrentPropertyGetter),
conversion: enumeratorInfo.CurrentConversion,
rewrittenType: elementType,
@checked: node.Checked),
conversion: node.ElementConversion,
rewrittenType: iterationVar.Type,
@checked: node.Checked);
// V v = (V)(T)e.Current;
BoundStatement iterationVarDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarAssignValue);
AddForEachIterationVariableSequencePoint(forEachSyntax, ref iterationVarDecl);
// while (e.MoveNext()) {
// V v = (V)(T)e.Current;
// /* node.Body */
// }
var rewrittenBodyBlock = CreateBlockDeclaringIterationVariable(iterationVar, iterationVarDecl, rewrittenBody, forEachSyntax);
BoundStatement whileLoop = RewriteWhileStatement(
syntax: forEachSyntax,
rewrittenCondition: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundEnumeratorVar,
method: enumeratorInfo.MoveNextMethod),
conditionSequencePointSpan: forEachSyntax.InKeyword.Span,
rewrittenBody: rewrittenBodyBlock,
breakLabel: node.BreakLabel,
continueLabel: node.ContinueLabel,
hasErrors: false);
BoundStatement result;
MethodSymbol disposeMethod;
if (enumeratorInfo.NeedsDisposeMethod && Binder.TryGetSpecialTypeMember(_compilation, SpecialMember.System_IDisposable__Dispose, forEachSyntax, _diagnostics, out disposeMethod))
{
Binder.ReportDiagnosticsIfObsolete(_diagnostics, disposeMethod, forEachSyntax,
hasBaseReceiver: false,
containingMember: _factory.CurrentMethod,
containingType: _factory.CurrentType,
location: enumeratorInfo.Location);
BoundBlock finallyBlockOpt;
var idisposableTypeSymbol = disposeMethod.ContainingType;
var conversions = new TypeConversions(_factory.CurrentMethod.ContainingAssembly.CorLibrary);
HashSet <DiagnosticInfo> useSiteDiagnostics = null;
var isImplicit = conversions.ClassifyImplicitConversion(enumeratorType, idisposableTypeSymbol, ref useSiteDiagnostics).IsImplicit;
_diagnostics.Add(forEachSyntax, useSiteDiagnostics);
if (isImplicit)
{
Debug.Assert(enumeratorInfo.NeedsDisposeMethod);
Conversion receiverConversion = enumeratorType.IsStructType() ?
Conversion.Boxing :
Conversion.ImplicitReference;
// ((IDisposable)e).Dispose(); or e.Dispose();
BoundStatement disposeCall = new BoundExpressionStatement(forEachSyntax,
expression: SynthesizeCall(forEachSyntax, boundEnumeratorVar, disposeMethod, receiverConversion, idisposableTypeSymbol));
BoundStatement disposeStmt;
if (enumeratorType.IsValueType)
{
// No way for the struct to be nullable and disposable.
Debug.Assert(((TypeSymbol)enumeratorType.OriginalDefinition).SpecialType != SpecialType.System_Nullable_T);
// For non-nullable structs, no null check is required.
disposeStmt = disposeCall;
}
else
{
// NB: cast to object missing from spec. Needed to ignore user-defined operators and box type parameters.
// if ((object)e != null) ((IDisposable)e).Dispose();
disposeStmt = RewriteIfStatement(
syntax: forEachSyntax,
rewrittenCondition: new BoundBinaryOperator(forEachSyntax,
operatorKind: BinaryOperatorKind.NotEqual,
left: MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: boundEnumeratorVar,
conversion: enumeratorInfo.EnumeratorConversion,
rewrittenType: _compilation.GetSpecialType(SpecialType.System_Object),
@checked: false),
right: MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Null,
type: null),
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: _compilation.GetSpecialType(SpecialType.System_Boolean)),
rewrittenConsequence: disposeCall,
rewrittenAlternativeOpt: null,
hasErrors: false);
}
finallyBlockOpt = new BoundBlock(forEachSyntax,
locals: ImmutableArray <LocalSymbol> .Empty,
statements: ImmutableArray.Create <BoundStatement>(disposeStmt));
}
else
{
Debug.Assert(!enumeratorType.IsSealed);
// IDisposable d
LocalSymbol disposableVar = _factory.SynthesizedLocal(idisposableTypeSymbol);
// Reference to d.
BoundLocal boundDisposableVar = MakeBoundLocal(forEachSyntax, disposableVar, idisposableTypeSymbol);
BoundTypeExpression boundIDisposableTypeExpr = new BoundTypeExpression(forEachSyntax,
aliasOpt: null,
type: idisposableTypeSymbol);
// e as IDisposable
BoundExpression disposableVarInitValue = new BoundAsOperator(forEachSyntax,
operand: boundEnumeratorVar,
targetType: boundIDisposableTypeExpr,
conversion: Conversion.ExplicitReference, // Explicit so the emitter won't optimize it away.
type: idisposableTypeSymbol);
// IDisposable d = e as IDisposable;
BoundStatement disposableVarDecl = MakeLocalDeclaration(forEachSyntax, disposableVar, disposableVarInitValue);
// if (d != null) d.Dispose();
BoundStatement ifStmt = RewriteIfStatement(
syntax: forEachSyntax,
rewrittenCondition: new BoundBinaryOperator(forEachSyntax,
operatorKind: BinaryOperatorKind.NotEqual, // reference equality
left: boundDisposableVar,
right: MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Null,
type: null),
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: _compilation.GetSpecialType(SpecialType.System_Boolean)),
rewrittenConsequence: new BoundExpressionStatement(forEachSyntax,
expression: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundDisposableVar,
method: disposeMethod)),
rewrittenAlternativeOpt: null,
hasErrors: false);
// IDisposable d = e as IDisposable;
// if (d != null) d.Dispose();
finallyBlockOpt = new BoundBlock(forEachSyntax,
locals: ImmutableArray.Create <LocalSymbol>(disposableVar),
statements: ImmutableArray.Create <BoundStatement>(disposableVarDecl, ifStmt));
}
// try {
// while (e.MoveNext()) {
// V v = (V)(T)e.Current;
// /* loop body */
// }
// }
// finally {
// /* dispose of e */
// }
BoundStatement tryFinally = new BoundTryStatement(forEachSyntax,
tryBlock: new BoundBlock(forEachSyntax,
locals: ImmutableArray <LocalSymbol> .Empty,
statements: ImmutableArray.Create <BoundStatement>(whileLoop)),
catchBlocks: ImmutableArray <BoundCatchBlock> .Empty,
finallyBlockOpt: finallyBlockOpt);
// E e = ((C)(x)).GetEnumerator();
// try {
// /* as above */
result = new BoundBlock(
syntax: forEachSyntax,
locals: ImmutableArray.Create(enumeratorVar),
statements: ImmutableArray.Create <BoundStatement>(enumeratorVarDecl, tryFinally));
}
else
{
// E e = ((C)(x)).GetEnumerator();
// while (e.MoveNext()) {
// V v = (V)(T)e.Current;
// /* loop body */
// }
result = new BoundBlock(
syntax: forEachSyntax,
locals: ImmutableArray.Create(enumeratorVar),
statements: ImmutableArray.Create <BoundStatement>(enumeratorVarDecl, whileLoop));
}
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return(result);
}
public override BoundStatement InstrumentForEachStatement(BoundForEachStatement original, BoundStatement rewritten)
{
return Previous.InstrumentForEachStatement(original, rewritten);
}
public virtual BoundStatement InstrumentForEachStatementConditionalGotoStart(BoundForEachStatement original, BoundStatement branchBack)
{
Debug.Assert(!original.WasCompilerGenerated);
Debug.Assert(original.Syntax is CommonForEachStatementSyntax);
return(branchBack);
}
/// <summary>
/// Lower a foreach loop that will enumerate the characters of a string.
///
/// string s = x;
/// for (int p = 0; p < s.Length; p = p + 1) {
/// V v = (V)s.Chars[p];
/// // body
/// }
/// </summary>
/// <remarks>
/// We will follow Dev10 in diverging from the C# 4 spec by ignoring string's
/// implementation of IEnumerable and just indexing into its characters.
///
/// NOTE: We're assuming that sequence points have already been generated.
/// Otherwise, lowering to for-loops would generated spurious ones.
/// </remarks>
private BoundStatement RewriteStringForEachStatement(BoundForEachStatement node)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)node.Syntax;
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
TypeSymbol stringType = collectionExpression.Type;
Debug.Assert(stringType.SpecialType == SpecialType.System_String);
TypeSymbol intType = _compilation.GetSpecialType(SpecialType.System_Int32);
TypeSymbol boolType = _compilation.GetSpecialType(SpecialType.System_Boolean);
BoundExpression rewrittenExpression = (BoundExpression)Visit(collectionExpression);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
// string s;
LocalSymbol stringVar = _factory.SynthesizedLocal(stringType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArray);
// int p;
LocalSymbol positionVar = _factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayIndex);
// Reference to s.
BoundLocal boundStringVar = MakeBoundLocal(forEachSyntax, stringVar, stringType);
// Reference to p.
BoundLocal boundPositionVar = MakeBoundLocal(forEachSyntax, positionVar, intType);
// string s = /*expr*/;
BoundStatement stringVarDecl = MakeLocalDeclaration(forEachSyntax, stringVar, rewrittenExpression);
AddForEachExpressionSequencePoint(forEachSyntax, ref stringVarDecl);
// int p = 0;
BoundStatement positionVariableDecl = MakeLocalDeclaration(forEachSyntax, positionVar,
MakeLiteral(forEachSyntax, ConstantValue.Default(SpecialType.System_Int32), intType));
// string s = /*node.Expression*/; int p = 0;
BoundStatement initializer = new BoundStatementList(forEachSyntax,
statements: ImmutableArray.Create<BoundStatement>(stringVarDecl, positionVariableDecl));
MethodSymbol method = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_String__Length);
BoundExpression stringLength = BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundStringVar,
method: method,
arguments: ImmutableArray<BoundExpression>.Empty);
// p < s.Length
BoundExpression exitCondition = new BoundBinaryOperator(
syntax: forEachSyntax,
operatorKind: BinaryOperatorKind.IntLessThan,
left: boundPositionVar,
right: stringLength,
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: boolType);
// p = p + 1;
BoundStatement positionIncrement = MakePositionIncrement(forEachSyntax, boundPositionVar, intType);
LocalSymbol iterationVar = node.IterationVariable;
TypeSymbol iterationVarType = iterationVar.Type;
Debug.Assert(node.ElementConversion.IsValid);
// (V)s.Chars[p]
MethodSymbol chars = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_String__Chars);
BoundExpression iterationVarInitValue = MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundStringVar,
method: chars,
arguments: ImmutableArray.Create<BoundExpression>(boundPositionVar)),
conversion: node.ElementConversion,
rewrittenType: iterationVarType,
@checked: node.Checked);
// V v = (V)s.Chars[p];
BoundStatement iterationVarDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarInitValue);
AddForEachIterationVariableSequencePoint(forEachSyntax, ref iterationVarDecl);
// { V v = (V)s.Chars[p]; /*node.Body*/ }
BoundStatement loopBody = CreateBlockDeclaringIterationVariable(iterationVar, iterationVarDecl, rewrittenBody, forEachSyntax);
// for (string s = /*node.Expression*/, int p = 0; p < s.Length; p = p + 1) {
// V v = (V)s.Chars[p];
// /*node.Body*/
// }
BoundStatement result = RewriteForStatement(
syntax: forEachSyntax,
outerLocals: ImmutableArray.Create(stringVar, positionVar),
rewrittenInitializer: initializer,
rewrittenCondition: exitCondition,
conditionSyntaxOpt: null,
conditionSpanOpt: forEachSyntax.InKeyword.Span,
rewrittenIncrement: positionIncrement,
rewrittenBody: loopBody,
breakLabel: node.BreakLabel,
continueLabel: node.ContinueLabel,
hasErrors: node.HasErrors);
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return result;
}
public override BoundStatement InstrumentForEachStatementDeconstructionVariablesDeclaration(BoundForEachStatement original, BoundStatement iterationVarDecl)
{
return(AddDynamicAnalysis(original, base.InstrumentForEachStatementDeconstructionVariablesDeclaration(original, iterationVarDecl)));
}
/// <summary>
/// Lower a foreach loop that will enumerate a multi-dimensional array.
///
/// A[...] a = x;
/// int q_0 = a.GetUpperBound(0), q_1 = a.GetUpperBound(1), ...;
/// for (int p_0 = a.GetLowerBound(0); p_0 <= q_0; p_0 = p_0 + 1)
/// for (int p_1 = a.GetLowerBound(1); p_1 <= q_1; p_1 = p_1 + 1)
/// ...
/// { V v = (V)a[p_0, p_1, ...]; /* body */ }
/// </summary>
/// <remarks>
/// We will follow Dev10 in diverging from the C# 4 spec by ignoring Array's
/// implementation of IEnumerable and just indexing into its elements.
///
/// NOTE: We're assuming that sequence points have already been generated.
/// Otherwise, lowering to nested for-loops would generated spurious ones.
/// </remarks>
private BoundStatement RewriteMultiDimensionalArrayForEachStatement(BoundForEachStatement node)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)node.Syntax;
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
Debug.Assert(collectionExpression.Type.IsArray());
ArrayTypeSymbol arrayType = (ArrayTypeSymbol)collectionExpression.Type;
int rank = arrayType.Rank;
Debug.Assert(!arrayType.IsSZArray);
TypeSymbol intType = _compilation.GetSpecialType(SpecialType.System_Int32);
TypeSymbol boolType = _compilation.GetSpecialType(SpecialType.System_Boolean);
// Values we'll use every iteration
MethodSymbol getLowerBoundMethod = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_Array__GetLowerBound);
MethodSymbol getUpperBoundMethod = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_Array__GetUpperBound);
BoundExpression rewrittenExpression = (BoundExpression)Visit(collectionExpression);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
// A[...] a
LocalSymbol arrayVar = _factory.SynthesizedLocal(arrayType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArray);
BoundLocal boundArrayVar = MakeBoundLocal(forEachSyntax, arrayVar, arrayType);
// A[...] a = /*node.Expression*/;
BoundStatement arrayVarDecl = MakeLocalDeclaration(forEachSyntax, arrayVar, rewrittenExpression);
AddForEachExpressionSequencePoint(forEachSyntax, ref arrayVarDecl);
// NOTE: dev10 initializes all of the upper bound temps before entering the loop (as opposed to
// initializing each one at the corresponding level of nesting). Doing it at the same time as
// the lower bound would make this code a bit simpler, but it would make it harder to compare
// the roslyn and dev10 IL.
// int q_0, q_1, ...
LocalSymbol[] upperVar = new LocalSymbol[rank];
BoundLocal[] boundUpperVar = new BoundLocal[rank];
BoundStatement[] upperVarDecl = new BoundStatement[rank];
for (int dimension = 0; dimension < rank; dimension++)
{
// int q_dimension
upperVar[dimension] = _factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayLimit);
boundUpperVar[dimension] = MakeBoundLocal(forEachSyntax, upperVar[dimension], intType);
ImmutableArray<BoundExpression> dimensionArgument = ImmutableArray.Create(
MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Create(dimension, ConstantValueTypeDiscriminator.Int32),
type: intType));
// a.GetUpperBound(dimension)
BoundExpression currentDimensionUpperBound = BoundCall.Synthesized(forEachSyntax, boundArrayVar, getUpperBoundMethod, dimensionArgument);
// int q_dimension = a.GetUpperBound(dimension);
upperVarDecl[dimension] = MakeLocalDeclaration(forEachSyntax, upperVar[dimension], currentDimensionUpperBound);
}
// int p_0, p_1, ...
LocalSymbol[] positionVar = new LocalSymbol[rank];
BoundLocal[] boundPositionVar = new BoundLocal[rank];
for (int dimension = 0; dimension < rank; dimension++)
{
positionVar[dimension] = _factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayIndex);
boundPositionVar[dimension] = MakeBoundLocal(forEachSyntax, positionVar[dimension], intType);
}
// V v
LocalSymbol iterationVar = node.IterationVariable;
TypeSymbol iterationVarType = iterationVar.Type;
// (V)a[p_0, p_1, ...]
BoundExpression iterationVarInitValue = MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: new BoundArrayAccess(forEachSyntax,
expression: boundArrayVar,
indices: ImmutableArray.Create((BoundExpression[])boundPositionVar),
type: arrayType.ElementType),
conversion: node.ElementConversion,
rewrittenType: iterationVarType,
@checked: node.Checked);
// V v = (V)a[p_0, p_1, ...];
BoundStatement iterationVarDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarInitValue);
AddForEachIterationVariableSequencePoint(forEachSyntax, ref iterationVarDecl);
// { V v = (V)a[p_0, p_1, ...]; /* node.Body */ }
BoundStatement innermostLoopBody = CreateBlockDeclaringIterationVariable(iterationVar, iterationVarDecl, rewrittenBody, forEachSyntax);
// work from most-nested to least-nested
// for (int p_0 = a.GetLowerBound(0); p_0 <= q_0; p_0 = p_0 + 1)
// for (int p_1 = a.GetLowerBound(0); p_1 <= q_1; p_1 = p_1 + 1)
// ...
// { V v = (V)a[p_0, p_1, ...]; /* node.Body */ }
BoundStatement forLoop = null;
for (int dimension = rank - 1; dimension >= 0; dimension--)
{
ImmutableArray<BoundExpression> dimensionArgument = ImmutableArray.Create(
MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Create(dimension, ConstantValueTypeDiscriminator.Int32),
type: intType));
// a.GetLowerBound(dimension)
BoundExpression currentDimensionLowerBound = BoundCall.Synthesized(forEachSyntax, boundArrayVar, getLowerBoundMethod, dimensionArgument);
// int p_dimension = a.GetLowerBound(dimension);
BoundStatement positionVarDecl = MakeLocalDeclaration(forEachSyntax, positionVar[dimension], currentDimensionLowerBound);
GeneratedLabelSymbol breakLabel = dimension == 0 // outermost for-loop
? node.BreakLabel // i.e. the one that break statements will jump to
: new GeneratedLabelSymbol("break"); // Should not affect emitted code since unused
// p_dimension <= q_dimension //NB: OrEqual
BoundExpression exitCondition = new BoundBinaryOperator(
syntax: forEachSyntax,
operatorKind: BinaryOperatorKind.IntLessThanOrEqual,
left: boundPositionVar[dimension],
right: boundUpperVar[dimension],
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: boolType);
// p_dimension = p_dimension + 1;
BoundStatement positionIncrement = MakePositionIncrement(forEachSyntax, boundPositionVar[dimension], intType);
BoundStatement body;
GeneratedLabelSymbol continueLabel;
if (forLoop == null)
{
// innermost for-loop
body = innermostLoopBody;
continueLabel = node.ContinueLabel; //i.e. the one continue statements will actually jump to
}
else
{
body = forLoop;
continueLabel = new GeneratedLabelSymbol("continue"); // Should not affect emitted code since unused
}
forLoop = RewriteForStatement(
syntax: forEachSyntax,
outerLocals: ImmutableArray.Create(positionVar[dimension]),
rewrittenInitializer: positionVarDecl,
rewrittenCondition: exitCondition,
conditionSyntaxOpt: null,
conditionSpanOpt: forEachSyntax.InKeyword.Span,
rewrittenIncrement: positionIncrement,
rewrittenBody: body,
breakLabel: breakLabel,
continueLabel: continueLabel,
hasErrors: node.HasErrors);
}
Debug.Assert(forLoop != null);
BoundStatement result = new BoundBlock(
forEachSyntax,
ImmutableArray.Create(arrayVar).Concat(upperVar.AsImmutableOrNull()),
ImmutableArray<LocalFunctionSymbol>.Empty,
ImmutableArray.Create(arrayVarDecl).Concat(upperVarDecl.AsImmutableOrNull()).Add(forLoop));
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return result;
}
public virtual BoundStatement InstrumentForEachStatementCollectionVarDeclaration(BoundForEachStatement original, BoundStatement collectionVarDecl)
{
Debug.Assert(!original.WasCompilerGenerated);
Debug.Assert(original.Syntax is CommonForEachStatementSyntax);
return(collectionVarDecl);
}
/// <summary>
/// So that the binding info can return an appropriate SemanticInfo.Converted type for the collection
/// expression of a foreach node, it is wrapped in a BoundConversion to the collection type in the
/// initial bound tree. However, we may be able to optimize away (or entirely disregard) the conversion
/// so we pull out the bound node for the underlying expression.
/// </summary>
private static BoundExpression GetUnconvertedCollectionExpression(BoundForEachStatement node)
{
var boundExpression = node.Expression;
if (boundExpression.Kind == BoundKind.Conversion)
{
return ((BoundConversion)boundExpression).Operand;
}
// Conversion was an identity conversion and the LocalRewriter must have optimized away the
// BoundConversion node, we can return the expression itself.
return boundExpression;
}
public virtual BoundStatement InstrumentForEachStatement(BoundForEachStatement original, BoundStatement rewritten)
{
Debug.Assert(original.Syntax is CommonForEachStatementSyntax);
return(InstrumentStatement(original, rewritten));
}
/// <summary>
/// Add sequence point |here|:
///
/// foreach (Type var in |expr|) { }
/// </summary>
/// <remarks>
/// Hit once, before looping begins.
/// </remarks>
public override BoundStatement InstrumentForEachStatementCollectionVarDeclaration(BoundForEachStatement original, BoundStatement collectionVarDecl)
{
// NOTE: This is slightly different from Dev10. In Dev10, when you stop the debugger
// on the collection expression, you can see the (uninitialized) iteration variable.
// In Roslyn, you cannot because the iteration variable is re-declared in each iteration
// of the loop and is, therefore, not yet in scope.
if (original.Syntax is ForEachComponentStatementSyntax)
{
return InstrumentForEachStatementDeconstructionVariablesDeclaration(original, collectionVarDecl);
}
var forEachSyntax = (ForEachStatementSyntax)original.Syntax;
return new BoundSequencePoint(forEachSyntax.Expression,
base.InstrumentForEachStatementCollectionVarDeclaration(original, collectionVarDecl));
}
public virtual BoundStatement InstrumentForEachStatementIterationVarDeclaration(BoundForEachStatement original, BoundStatement iterationVarDecl)
{
Debug.Assert(!original.WasCompilerGenerated);
Debug.Assert(original.Syntax.Kind() == SyntaxKind.ForEachStatement);
return(iterationVarDecl);
}
/// <summary>
/// Add sequence point |here|:
///
/// |foreach| (Type var in expr) { }
/// </summary>
/// <remarks>
/// Hit once, before looping begins.
/// </remarks>
public override BoundStatement InstrumentForEachStatement(BoundForEachStatement original, BoundStatement rewritten)
{
var forEachSyntax = (CommonForEachStatementSyntax)original.Syntax;
BoundSequencePointWithSpan foreachKeywordSequencePoint = new BoundSequencePointWithSpan(forEachSyntax, null, forEachSyntax.ForEachKeyword.Span);
return new BoundStatementList(forEachSyntax,
ImmutableArray.Create<BoundStatement>(foreachKeywordSequencePoint,
base.InstrumentForEachStatement(original, rewritten)));
}
public virtual BoundStatement InstrumentForEachStatement(BoundForEachStatement original, BoundStatement rewritten)
{
Debug.Assert(original.Syntax.Kind() == SyntaxKind.ForEachStatement);
return InstrumentStatement(original, rewritten);
}
public override BoundStatement InstrumentForEachStatementGotoEnd(BoundForEachStatement original, BoundStatement gotoEnd)
{
return ForStatementCreateGotoEndSequencePoint(base.InstrumentForEachStatementGotoEnd(original, gotoEnd));
}
public virtual BoundStatement InstrumentForEachStatementDeconstructionVariablesDeclaration(BoundForEachStatement original, BoundStatement iterationVarDecl)
{
Debug.Assert(!original.WasCompilerGenerated);
Debug.Assert(original.Syntax.Kind() == SyntaxKind.ForEachStatement);
Debug.Assert(((ForEachStatementSyntax)original.Syntax).IsDeconstructionDeclaration);
return iterationVarDecl;
}
public override BoundStatement InstrumentForEachStatementGotoContinue(BoundForEachStatement original, BoundStatement gotoContinue)
{
return new BoundSequencePoint(null, base.InstrumentForEachStatementGotoContinue(original, gotoContinue));
}
public virtual BoundStatement InstrumentForEachStatementGotoContinue(BoundForEachStatement original, BoundStatement gotoContinue)
{
Debug.Assert(!original.WasCompilerGenerated);
Debug.Assert(original.Syntax is CommonForEachStatementSyntax);
return(gotoContinue);
}