public override BoundNode VisitTryStatement(BoundTryStatement node)
{
EnsureOnlyEvalStack();
var tryBlock = (BoundBlock)this.Visit(node.TryBlock);
var catchBlocks = this.VisitList(node.CatchBlocks);
EnsureOnlyEvalStack();
var finallyBlock = (BoundBlock)this.Visit(node.FinallyBlockOpt);
EnsureOnlyEvalStack();
return node.Update(tryBlock, catchBlocks, finallyBlock, node.PreferFaultHandler);
}
private void EmitTryStatement(BoundTryStatement statement, bool emitCatchesOnly = false)
{
Debug.Assert(!statement.CatchBlocks.IsDefault);
// Stack must be empty at beginning of try block.
_builder.AssertStackEmpty();
// IL requires catches and finally block to be distinct try
// blocks so if the source contained both a catch and
// a finally, nested scopes are emitted.
bool emitNestedScopes = (!emitCatchesOnly &&
(statement.CatchBlocks.Length > 0) &&
(statement.FinallyBlockOpt != null));
_builder.OpenLocalScope(ScopeType.TryCatchFinally);
_builder.OpenLocalScope(ScopeType.Try);
// IL requires catches and finally block to be distinct try
// blocks so if the source contained both a catch and
// a finally, nested scopes are emitted.
_tryNestingLevel++;
if (emitNestedScopes)
{
EmitTryStatement(statement, emitCatchesOnly: true);
}
else
{
EmitBlock(statement.TryBlock);
}
_tryNestingLevel--;
// Close the Try scope
_builder.CloseLocalScope();
if (!emitNestedScopes)
{
foreach (var catchBlock in statement.CatchBlocks)
{
EmitCatchBlock(catchBlock);
}
}
if (!emitCatchesOnly && (statement.FinallyBlockOpt != null))
{
_builder.OpenLocalScope(statement.PreferFaultHandler ? ScopeType.Fault : ScopeType.Finally);
EmitBlock(statement.FinallyBlockOpt);
// close Finally scope
_builder.CloseLocalScope();
// close the whole try statement scope
_builder.CloseLocalScope();
// in a case where we emit surrogate Finally using Fault, we emit code like this
//
// try{
// . . .
// } fault {
// finallyBlock;
// }
// finallyBlock;
//
// This is where the second copy of finallyBlock is emitted.
if (statement.PreferFaultHandler)
{
var finallyClone = FinallyCloner.MakeFinallyClone(statement);
EmitBlock(finallyClone);
}
}
else
{
// close the whole try statement scope
_builder.CloseLocalScope();
}
}
/// <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 = new TempLocalSymbol(enumeratorType, RefKind.None, this.containingMethod);
// 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 = SynthesizeConversion(
syntax: forEachSyntax,
operand: SynthesizeConversion(
syntax: forEachSyntax,
operand: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundEnumeratorVar,
method: enumeratorInfo.CurrentPropertyGetter),
conversion: enumeratorInfo.CurrentConversion,
type: elementType),
conversion: node.ElementConversion,
type: iterationVar.Type);
// 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 */
// }
BoundStatement whileLoop = RewriteWhileStatement(
syntax: forEachSyntax,
rewrittenCondition: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundEnumeratorVar,
method: enumeratorInfo.MoveNextMethod),
conditionSequencePointSpan: forEachSyntax.InKeyword.Span,
rewrittenBody: new BoundBlock(rewrittenBody.Syntax,
statements: ReadOnlyArray<BoundStatement>.CreateFrom(iterationVarDecl, rewrittenBody),
localsOpt: ReadOnlyArray<LocalSymbol>.CreateFrom(iterationVar)),
breakLabel: node.BreakLabel,
continueLabel: node.ContinueLabel,
hasErrors: false);
BoundStatement result;
if (enumeratorInfo.DisposeMethodOpt != null)
{
BoundBlock finallyBlockOpt;
var idisposableTypeSymbol = enumeratorInfo.DisposeMethodOpt.ContainingType;
var conversions = new TypeConversions(this.containingMethod.ContainingAssembly.CorLibrary);
if (conversions.ClassifyImplicitConversion(enumeratorType, idisposableTypeSymbol).IsImplicit)
{
Debug.Assert(enumeratorInfo.DisposeMethodOpt != null);
Conversion receiverConversion = enumeratorType.IsStructType() ?
Conversion.Boxing :
Conversion.ImplicitReference;
// ((IDisposable)e).Dispose(); or e.Dispose();
BoundStatement disposeCall = new BoundExpressionStatement(forEachSyntax,
expression: SynthesizeCall(forEachSyntax, boundEnumeratorVar, enumeratorInfo.DisposeMethodOpt, 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: SynthesizeConversion(
syntax: forEachSyntax,
operand: boundEnumeratorVar,
conversion: enumeratorInfo.EnumeratorConversion,
type: this.compilation.GetSpecialType(SpecialType.System_Object)),
right: new BoundLiteral(forEachSyntax,
constantValueOpt: ConstantValue.Null,
type: null),
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: this.compilation.GetSpecialType(SpecialType.System_Boolean)),
rewrittenConsequence: disposeCall,
rewrittenAlternativeOpt: null,
hasErrors: false);
}
finallyBlockOpt = new BoundBlock(forEachSyntax,
localsOpt: ReadOnlyArray<LocalSymbol>.Null,
statements: ReadOnlyArray<BoundStatement>.CreateFrom(disposeStmt));
}
else
{
Debug.Assert(!enumeratorType.IsSealed);
// IDisposable d
LocalSymbol disposableVar = new TempLocalSymbol(idisposableTypeSymbol, RefKind.None, this.containingMethod);
// Reference to d.
BoundLocal boundDisposableVar = MakeBoundLocal(forEachSyntax, disposableVar, idisposableTypeSymbol);
BoundTypeExpression boundIDisposableTypeExpr = new BoundTypeExpression(forEachSyntax,
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: new BoundLiteral(forEachSyntax,
constantValueOpt: ConstantValue.Null,
type: null),
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: this.compilation.GetSpecialType(SpecialType.System_Boolean)),
rewrittenConsequence: new BoundExpressionStatement(forEachSyntax,
expression: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundDisposableVar,
method: enumeratorInfo.DisposeMethodOpt)),
rewrittenAlternativeOpt: null,
hasErrors: false);
// IDisposable d = e as IDisposable;
// if (d != null) d.Dispose();
finallyBlockOpt = new BoundBlock(forEachSyntax,
localsOpt: ReadOnlyArray<LocalSymbol>.CreateFrom(disposableVar),
statements: ReadOnlyArray<BoundStatement>.CreateFrom(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,
localsOpt: ReadOnlyArray<LocalSymbol>.Empty,
statements: ReadOnlyArray<BoundStatement>.CreateFrom(whileLoop)),
catchBlocks: ReadOnlyArray<BoundCatchBlock>.Empty,
finallyBlockOpt: finallyBlockOpt);
// E e = ((C)(x)).GetEnumerator();
// try {
// /* as above */
result = new BoundBlock(
syntax: forEachSyntax,
localsOpt: ReadOnlyArray<LocalSymbol>.CreateFrom(enumeratorVar),
statements: ReadOnlyArray<BoundStatement>.CreateFrom(enumeratorVarDecl, tryFinally));
}
else
{
// E e = ((C)(x)).GetEnumerator();
// while (e.MoveNext()) {
// V v = (V)(T)e.Current;
// /* loop body */
// }
result = new BoundBlock(
syntax: forEachSyntax,
localsOpt: ReadOnlyArray<LocalSymbol>.CreateFrom(enumeratorVar),
statements: ReadOnlyArray<BoundStatement>.CreateFrom(enumeratorVarDecl, whileLoop));
}
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return result;
}
/// <summary>
/// The argument is BoundTryStatement (and not a BoundBlock) specifically
/// to support only Finally blocks where it is guaranteed to not have incoming or leaving branches.
/// </summary>
public static BoundBlock MakeFinallyClone(BoundTryStatement node)
{
var cloner = new FinallyCloner();
return (BoundBlock)cloner.Visit(node.FinallyBlockOpt);
}
internal bool Parse(BoundStatementList boundStatementList)
{
if (boundStatementList == null)
{
throw new ArgumentNullException();
}
var stage = Stages.Initialization;
var statementList = Unwrap(boundStatementList);
// in case of multi array if current statmentList contains BoundBlock you should process all statements into Initial stage
if (statementList.Statements.Last() is BoundBlock &&
!(statementList.Statements.Take(statementList.Statements.Length - 1).All(s => s is BoundBlock)))
{
return(false);
}
var mainBlock = boundStatementList as BoundBlock;
if (mainBlock != null)
{
ParseLocals(mainBlock.Locals, this.Locals);
}
var innerBlock = statementList as BoundBlock;
if (innerBlock != null && (object)mainBlock != (object)innerBlock)
{
ParseLocals(innerBlock.Locals, this.Locals);
}
foreach (var boundStatement in IterateBoundStatementsList(statementList))
{
BoundTryStatement boundTryStatement = null;
if (stage == Stages.Initialization)
{
boundTryStatement = boundStatement as BoundTryStatement;
if (boundTryStatement != null)
{
stage = Stages.TryBody;
}
else
{
var boundGotoStatement = boundStatement as BoundGotoStatement;
if (boundGotoStatement != null)
{
continue;
}
}
}
switch (stage)
{
case Stages.Initialization:
var statement = Deserialize(boundStatement, specialCase: SpecialCases.ForEachBody);
MergeOrSet(ref this._initialization, statement);
break;
case Stages.TryBody:
this.TryStatement = new TryStatement();
// apply special parsing to block of try
var whileStatement = new WhileStatement();
if (!whileStatement.Parse(
boundTryStatement.TryBlock.Statements.OfType <BoundStatementList>().First()))
{
Trace.Assert(false, "Can't parse while statement");
}
this.TryStatement.TryBlock = whileStatement;
if (boundTryStatement.FinallyBlockOpt != null)
{
this.TryStatement.FinallyBlockOpt = Deserialize(
boundTryStatement.FinallyBlockOpt,
specialCase: SpecialCases.ForEachBody);
}
break;
default:
throw new ArgumentOutOfRangeException();
}
}
return(stage == Stages.TryBody);
}
