// Rewriting for integral and string switch statements.
//
// For switch statements, we have an option of completely rewriting the switch header
// and switch sections into simpler constructs, i.e. we can rewrite the switch header
// using bound conditional goto statements and the rewrite the switch sections into
// bound labeleled statements.
// However, all the logic for emitting the switch jump tables is language agnostic
// and includes IL optimizations. Hence we delay the switch jump table generation
// till the emit phase. This way we also get additional benefit of sharing this code
// between both VB and C# compilers.
// For integral switch statements, we delay almost all the work
// to the emit phase.
// For string switch statements, we need to determine if we are generating a hash
// table based jump table or a non hash jump table, i.e. linear string comparisons
// with each case label. We use the Dev10 Heuristic to determine this
// (see SwitchStringJumpTableEmitter.ShouldGenerateHashTableSwitch() for details).
// If we are generating a hash table based jump table, we use a simple customizable
// hash function to hash the string constants corresponding to the case labels.
// See SwitchStringJumpTableEmitter.ComputeStringHash().
// We need to emit this function to compute the hash value into the compiler generate
// <PrivateImplementationDetails> class.
// If we have at least one string switch statement in a module that needs a
// hash table based jump table, we generate a single public string hash sythesized method
// that is shared across the module.
public override BoundNode VisitSwitchStatement(BoundSwitchStatement node)
{
var syntax = node.Syntax;
var rewrittenExpression = (BoundExpression)Visit(node.BoundExpression);
var rewrittenSections = VisitSwitchSections(node.SwitchSections);
var rewrittenStatement = MakeSwitchStatement(syntax, AddConditionSequencePoint(rewrittenExpression, node), rewrittenSections, node.ConstantTargetOpt, node.InnerLocals, node.BreakLabel, node);
if (!node.OuterLocals.IsEmpty)
{
rewrittenStatement = new BoundBlock(syntax, node.OuterLocals, ImmutableArray.Create(rewrittenStatement));
}
// Create the sequence point if generating debug info and
// node is not compiler generated
if (this.generateDebugInfo && !node.WasCompilerGenerated)
{
SwitchStatementSyntax switchSyntax = (SwitchStatementSyntax)syntax;
TextSpan switchSequencePointSpan = TextSpan.FromBounds(
switchSyntax.SwitchKeyword.SpanStart,
switchSyntax.CloseParenToken.Span.End);
return new BoundSequencePointWithSpan(
syntax: syntax,
statementOpt: rewrittenStatement,
span: switchSequencePointSpan,
hasErrors: false);
}
return rewrittenStatement;
}
internal static BoundBlock Rewrite(SourceMethodSymbol sourceMethodSymbol, MethodContractSyntax contract, BoundBlock body, TypeCompilationState compilationState, DiagnosticBag diagsForCurrentMethod)
{
var binder = compilationState.Compilation.GetBinderFactory(sourceMethodSymbol.SyntaxTree)
.GetBinder(body.Syntax);
SyntheticBoundNodeFactory factory = new SyntheticBoundNodeFactory(sourceMethodSymbol, sourceMethodSymbol.SyntaxNode, compilationState, diagsForCurrentMethod);
var contractType = compilationState.Compilation.GetTypeByReflectionType(typeof(System.Diagnostics.Contracts.Contract), diagsForCurrentMethod);
var contractStatements = ArrayBuilder<BoundStatement>.GetInstance(contract.Requires.Count);
foreach (var requires in contract.Requires)
{
var condition = binder.BindExpression(requires.Condition, diagsForCurrentMethod);
var methodCall = factory.StaticCall(contractType, "Requires", condition);
var statement = factory.ExpressionStatement(methodCall);
contractStatements.Add(statement);
}
foreach (var requires in contract.Ensures)
{
var condition = binder.BindExpression(requires.Condition, diagsForCurrentMethod);
var methodCall = factory.StaticCall(contractType, "Ensures", condition);
var statement = factory.ExpressionStatement(methodCall);
contractStatements.Add(statement);
}
return body.Update(body.Locals, body.Statements.InsertRange(0, contractStatements.ToImmutableAndFree()));
}
public BoundLambda(CSharpSyntaxNode syntax, BoundBlock body, ImmutableArray<Diagnostic> diagnostics, Binder binder, TypeSymbol delegateType, bool inferReturnType)
: this(syntax, (LambdaSymbol)binder.ContainingMemberOrLambda, body, diagnostics, binder, delegateType)
{
if (inferReturnType)
{
this._inferredReturnType = InferReturnType(
this.Body,
this.Binder,
delegateType,
this.Symbol.IsAsync,
ref this._inferredReturnTypeUseSiteDiagnostics,
out this._refKind,
out this._inferredFromSingleType);
#if DEBUG
_hasInferredReturnType = true;
#endif
}
Debug.Assert(
syntax.IsAnonymousFunction() || // lambda expressions
syntax is ExpressionSyntax && LambdaUtilities.IsLambdaBody(syntax, allowReducedLambdas: true) || // query lambdas
LambdaUtilities.IsQueryPairLambda(syntax) // "pair" lambdas in queries
);
}
/// <summary>
/// The flow analysis pass. This pass reports required diagnostics for unreachable
/// statements and uninitialized variables (through the call to FlowAnalysisWalker.Analyze),
/// and inserts a final return statement if the end of a void-returning method is reachable.
/// </summary>
/// <param name="method">the method to be analyzed</param>
/// <param name="block">the method's body</param>
/// <param name="diagnostics">the receiver of the reported diagnostics</param>
/// <returns>the rewritten block for the method (with a return statement possibly inserted)</returns>
public static BoundBlock Rewrite(
MethodSymbol method,
BoundBlock block,
DiagnosticBag diagnostics)
{
var compilation = method.DeclaringCompilation;
if (method.ReturnsVoid || (object)method.IteratorElementType != null
|| (method.IsAsync && compilation.GetWellKnownType(WellKnownType.System_Threading_Tasks_Task) == method.ReturnType))
{
if (method.IsImplicitlyDeclared || Analyze(compilation, method, block, diagnostics))
{
// we don't analyze synthesized void methods.
var sourceMethod = method as SourceMethodSymbol;
block = AppendImplicitReturn(block, method, (object)sourceMethod != null ? sourceMethod.BlockSyntax : null);
}
}
else if (Analyze(compilation, method, block, diagnostics))
{
// If the method is a lambda expression being converted to a non-void delegate type
// and the end point is reachable then suppress the error here; a special error
// will be reported by the lambda binder.
Debug.Assert(method.MethodKind != MethodKind.AnonymousFunction);
// If there's more than one location, then the method is partial and we
// have already reported a non-void partial method error.
if (method.Locations.Length == 1)
{
diagnostics.Add(ErrorCode.ERR_ReturnExpected, method.Locations[0], method);
}
}
return block;
}
public override BoundNode VisitBlock(BoundBlock node)
{
if (!this.Instrument || (node != _rootStatement && (node.WasCompilerGenerated || node.Syntax.Kind() != SyntaxKind.Block)))
{
return node.Update(node.Locals, node.LocalFunctions, VisitList(node.Statements));
}
var builder = ArrayBuilder<BoundStatement>.GetInstance();
for (int i = 0; i < node.Statements.Length; i++)
{
var stmt = (BoundStatement)Visit(node.Statements[i]);
if (stmt != null) builder.Add(stmt);
}
LocalSymbol synthesizedLocal;
BoundStatement prologue = _instrumenter.CreateBlockPrologue(node, out synthesizedLocal);
if (prologue != null)
{
builder.Insert(0, prologue);
}
BoundStatement epilogue = _instrumenter.CreateBlockEpilogue(node);
if (epilogue != null)
{
builder.Add(epilogue);
}
return new BoundBlock(node.Syntax, synthesizedLocal == null ? node.Locals : node.Locals.Add(synthesizedLocal), node.LocalFunctions, builder.ToImmutableAndFree(), node.HasErrors);
}
public override BoundNode VisitBlock(BoundBlock node)
{
if (node.WasCompilerGenerated || !this.generateDebugInfo)
{
return node.Update(node.LocalsOpt, VisitList(node.Statements));
}
BlockSyntax syntax = node.Syntax as BlockSyntax;
Debug.Assert(syntax != null);
var builder = ArrayBuilder<BoundStatement>.GetInstance();
var oBspan = syntax.OpenBraceToken.Span;
builder.Add(new BoundSequencePointWithSpan(syntax, null, oBspan));
for (int i = 0; i < node.Statements.Length; i++)
{
var stmt = (BoundStatement)Visit(node.Statements[i]);
if (stmt != null) builder.Add(stmt);
}
// no need to mark "}" on the outermost block
// as it cannot leave it normally. The block will have "return" at the end.
if (syntax.Parent == null || !(syntax.Parent.IsAnonymousFunction() || syntax.Parent is BaseMethodDeclarationSyntax))
{
var cBspan = syntax.CloseBraceToken.Span;
builder.Add(new BoundSequencePointWithSpan(syntax, null, cBspan));
}
return new BoundBlock(syntax, node.LocalsOpt, builder.ToImmutableAndFree(), node.HasErrors);
}
/// <summary>
/// The flow analysis pass. This pass reports required diagnostics for unreachable
/// statements and uninitialized variables (through the call to FlowAnalysisWalker.Analyze),
/// and inserts a final return statement if the end of a void-returning method is reachable.
/// </summary>
/// <param name="method">the method to be analyzed</param>
/// <param name="block">the method's body</param>
/// <param name="diagnostics">the receiver of the reported diagnostics</param>
/// <param name="hasTrailingExpression">indicates whether this Script had a trailing expression</param>
/// <param name="originalBodyNested">the original method body is the last statement in the block</param>
/// <returns>the rewritten block for the method (with a return statement possibly inserted)</returns>
public static BoundBlock Rewrite(
MethodSymbol method,
BoundBlock block,
DiagnosticBag diagnostics,
bool hasTrailingExpression,
bool originalBodyNested)
{
#if DEBUG
// We should only see a trailingExpression if we're in a Script initializer.
Debug.Assert(!hasTrailingExpression || method.IsScriptInitializer);
var initialDiagnosticCount = diagnostics.ToReadOnly().Length;
#endif
var compilation = method.DeclaringCompilation;
if (method.ReturnsVoid || method.IsIterator ||
(method.IsAsync && compilation.GetWellKnownType(WellKnownType.System_Threading_Tasks_Task) == method.ReturnType))
{
// we don't analyze synthesized void methods.
if ((method.IsImplicitlyDeclared && !method.IsScriptInitializer) || Analyze(compilation, method, block, diagnostics))
{
block = AppendImplicitReturn(block, method, (CSharpSyntaxNode)(method as SourceMethodSymbol)?.BodySyntax, originalBodyNested);
}
}
else if (Analyze(compilation, method, block, diagnostics))
{
// If the method is a lambda expression being converted to a non-void delegate type
// and the end point is reachable then suppress the error here; a special error
// will be reported by the lambda binder.
Debug.Assert(method.MethodKind != MethodKind.AnonymousFunction);
// Add implicit "return default(T)" if this is a submission that does not have a trailing expression.
var submissionResultType = (method as SynthesizedInteractiveInitializerMethod)?.ResultType;
if (!hasTrailingExpression && ((object)submissionResultType != null))
{
Debug.Assert(submissionResultType.SpecialType != SpecialType.System_Void);
var trailingExpression = new BoundDefaultOperator(method.GetNonNullSyntaxNode(), submissionResultType);
var newStatements = block.Statements.Add(new BoundReturnStatement(trailingExpression.Syntax, trailingExpression));
block = new BoundBlock(block.Syntax, ImmutableArray<LocalSymbol>.Empty, newStatements) { WasCompilerGenerated = true };
#if DEBUG
// It should not be necessary to repeat analysis after adding this node, because adding a trailing
// return in cases where one was missing should never produce different Diagnostics.
var flowAnalysisDiagnostics = DiagnosticBag.GetInstance();
Debug.Assert(!Analyze(compilation, method, block, flowAnalysisDiagnostics));
Debug.Assert(flowAnalysisDiagnostics.ToReadOnly().SequenceEqual(diagnostics.ToReadOnly().Skip(initialDiagnosticCount)));
flowAnalysisDiagnostics.Free();
#endif
}
// If there's more than one location, then the method is partial and we
// have already reported a non-void partial method error.
else if (method.Locations.Length == 1)
{
diagnostics.Add(ErrorCode.ERR_ReturnExpected, method.Locations[0], method);
}
}
return block;
}
public override BoundStatement CreateBlockPrologue(BoundBlock original, out LocalSymbol synthesizedLocal)
{
BoundStatement previousPrologue = base.CreateBlockPrologue(original, out synthesizedLocal);
if (_methodBody == original)
{
_dynamicAnalysisSpans = _spansBuilder.ToImmutableAndFree();
// In the future there will be multiple analysis kinds.
const int analysisKind = 0;
ArrayTypeSymbol modulePayloadType = ArrayTypeSymbol.CreateCSharpArray(_methodBodyFactory.Compilation.Assembly, _payloadType);
// Synthesize the initialization of the instrumentation payload array, using concurrency-safe code:
//
// var payload = PID.PayloadRootField[methodIndex];
// if (payload == null)
// payload = Instrumentation.CreatePayload(mvid, methodIndex, fileIndex, ref PID.PayloadRootField[methodIndex], payloadLength);
BoundStatement payloadInitialization = _methodBodyFactory.Assignment(_methodBodyFactory.Local(_methodPayload), _methodBodyFactory.ArrayAccess(_methodBodyFactory.InstrumentationPayloadRoot(analysisKind, modulePayloadType), ImmutableArray.Create(_methodBodyFactory.MethodDefIndex(_method))));
BoundExpression mvid = _methodBodyFactory.ModuleVersionId();
BoundExpression methodToken = _methodBodyFactory.MethodDefIndex(_method);
BoundExpression fileIndex = _methodBodyFactory.SourceDocumentIndex(GetSourceDocument(_methodBody.Syntax));
BoundExpression payloadSlot = _methodBodyFactory.ArrayAccess(_methodBodyFactory.InstrumentationPayloadRoot(analysisKind, modulePayloadType), ImmutableArray.Create(_methodBodyFactory.MethodDefIndex(_method)));
BoundStatement createPayloadCall = _methodBodyFactory.Assignment(_methodBodyFactory.Local(_methodPayload), _methodBodyFactory.Call(null, _createPayload, mvid, methodToken, fileIndex, payloadSlot, _methodBodyFactory.Literal(_dynamicAnalysisSpans.Length)));
BoundExpression payloadNullTest = _methodBodyFactory.Binary(BinaryOperatorKind.ObjectEqual, _methodBodyFactory.SpecialType(SpecialType.System_Boolean), _methodBodyFactory.Local(_methodPayload), _methodBodyFactory.Null(_payloadType));
BoundStatement payloadIf = _methodBodyFactory.If(payloadNullTest, createPayloadCall);
Debug.Assert(synthesizedLocal == null);
synthesizedLocal = _methodPayload;
ArrayBuilder<BoundStatement> prologueStatements = ArrayBuilder<BoundStatement>.GetInstance(previousPrologue == null ? 3 : 4);
prologueStatements.Add(payloadInitialization);
prologueStatements.Add(payloadIf);
if (_methodEntryInstrumentation != null)
{
prologueStatements.Add(_methodEntryInstrumentation);
}
if (previousPrologue != null)
{
prologueStatements.Add(previousPrologue);
}
return _methodBodyFactory.StatementList(prologueStatements.ToImmutableAndFree());
}
return previousPrologue;
}
private static BoundBlock AppendImplicitReturn(BoundBlock body, MethodSymbol method, CSharpSyntaxNode syntax, bool originalBodyNested)
{
if (originalBodyNested)
{
var statements = body.Statements;
int n = statements.Length;
var builder = ArrayBuilder<BoundStatement>.GetInstance(n);
builder.AddRange(statements, n - 1);
builder.Add(AppendImplicitReturn((BoundBlock)statements[n - 1], method, syntax));
return body.Update(body.Locals, ImmutableArray<LocalFunctionSymbol>.Empty, builder.ToImmutableAndFree());
}
else
{
return AppendImplicitReturn(body, method, syntax);
}
}
private static TypeSymbol InferReturnType(BoundBlock block, Binder binder, bool isAsync, ref HashSet<DiagnosticInfo> useSiteDiagnostics, out bool inferredFromSingleType)
{
int numberOfDistinctReturns;
var resultTypes = BlockReturns.GetReturnTypes(block, out numberOfDistinctReturns);
inferredFromSingleType = numberOfDistinctReturns < 2;
TypeSymbol bestResultType;
if (resultTypes.IsDefaultOrEmpty)
{
bestResultType = null;
}
else if (resultTypes.Length == 1)
{
bestResultType = resultTypes[0];
}
else
{
bestResultType = BestTypeInferrer.InferBestType(resultTypes, binder.Conversions, ref useSiteDiagnostics);
}
if (!isAsync)
{
return bestResultType;
}
// Async:
if (resultTypes.IsEmpty)
{
// No return statements have expressions; inferred type Task:
return binder.Compilation.GetWellKnownType(WellKnownType.System_Threading_Tasks_Task);
}
if ((object)bestResultType == null || bestResultType.SpecialType == SpecialType.System_Void)
{
// If the best type was 'void', ERR_CantReturnVoid is reported while binding the "return void"
// statement(s).
return null;
}
// Some non-void best type T was found; infer type Task<T>:
return binder.Compilation.GetWellKnownType(WellKnownType.System_Threading_Tasks_Task_T).Construct(bestResultType);
}
private BoundNode VisitLocalFunctionOrLambda(BoundBlock body)
{
var oldPending = SavePending(); // We do not support branches *into* a lambda.
LocalState finalState = this.State;
this.State = ReachableState();
var oldPending2 = SavePending();
VisitAlways(body);
RestorePending(oldPending2); // process any forward branches within the lambda body
ImmutableArray<PendingBranch> pendingReturns = RemoveReturns();
RestorePending(oldPending);
IntersectWith(ref finalState, ref this.State);
foreach (PendingBranch returnBranch in pendingReturns)
{
this.State = returnBranch.State;
IntersectWith(ref finalState, ref this.State);
}
this.State = finalState;
return null;
}
// insert the implicit "return" statement at the end of the method body
// Normally, we wouldn't bother attaching syntax trees to compiler-generated nodes, but these
// ones are going to have sequence points.
internal static BoundBlock AppendImplicitReturn(BoundBlock body, MethodSymbol method, CSharpSyntaxNode syntax = null)
{
Debug.Assert(body != null);
Debug.Assert(method != null);
if (syntax == null)
{
syntax = body.Syntax;
}
Debug.Assert(body.WasCompilerGenerated || syntax.IsKind(SyntaxKind.Block) || syntax.IsKind(SyntaxKind.ArrowExpressionClause));
BoundStatement ret = method.IsIterator
? (BoundStatement)BoundYieldBreakStatement.Synthesized(syntax)
: BoundReturnStatement.Synthesized(syntax, null);
// Implicitly added return for async method does not need sequence points since lowering would add one.
if (syntax.IsKind(SyntaxKind.Block) && !method.IsAsync)
{
var blockSyntax = (BlockSyntax)syntax;
ret = new BoundSequencePointWithSpan(
blockSyntax,
ret,
blockSyntax.CloseBraceToken.Span)
{ WasCompilerGenerated = true };
}
switch (body.Kind)
{
case BoundKind.Block:
var block = (BoundBlock)body;
return block.Update(block.Locals, block.LocalFunctions, block.Statements.Add(ret));
default:
return new BoundBlock(syntax, ImmutableArray<LocalSymbol>.Empty, ImmutableArray<LocalFunctionSymbol>.Empty, ImmutableArray.Create(ret, body));
}
}
/// <summary>
/// Lower "using (ResourceType resource = expression) statement" to a try-finally block.
/// </summary>
/// <remarks>
/// Assumes that the local symbol will be declared (i.e. in the LocalsOpt array) of an enclosing block.
/// Assumes that using statements with multiple locals have already been split up into multiple using statements.
/// </remarks>
private BoundBlock RewriteDeclarationUsingStatement(CSharpSyntaxNode usingSyntax, BoundLocalDeclaration localDeclaration, BoundBlock tryBlock, Conversion idisposableConversion)
{
CSharpSyntaxNode declarationSyntax = localDeclaration.Syntax;
LocalSymbol localSymbol = localDeclaration.LocalSymbol;
TypeSymbol localType = localSymbol.Type;
Debug.Assert((object)localType != null); //otherwise, there wouldn't be a conversion to IDisposable
BoundLocal boundLocal = new BoundLocal(declarationSyntax, localSymbol, localDeclaration.InitializerOpt.ConstantValue, localType);
BoundStatement rewrittenDeclaration = (BoundStatement)Visit(localDeclaration);
// If we know that the expression is null, then we know that the null check in the finally block
// will fail, and the Dispose call will never happen. That is, the finally block will have no effect.
// Consequently, we can simply skip the whole try-finally construct and just create a block containing
// the new declaration.
if (boundLocal.ConstantValue == ConstantValue.Null)
{
//localSymbol will be declared by an enclosing block
return BoundBlock.SynthesizedNoLocals(usingSyntax, rewrittenDeclaration, tryBlock);
}
if (localType.IsDynamic())
{
BoundExpression tempInit = MakeConversion(
declarationSyntax,
boundLocal,
idisposableConversion,
compilation.GetSpecialType(SpecialType.System_IDisposable),
@checked: false);
BoundAssignmentOperator tempAssignment;
BoundLocal boundTemp = this.factory.StoreToTemp(tempInit, out tempAssignment);
BoundStatement tryFinally = RewriteUsingStatementTryFinally(usingSyntax, tryBlock, boundTemp);
return new BoundBlock(
syntax: usingSyntax,
locals: ImmutableArray.Create<LocalSymbol>(boundTemp.LocalSymbol), //localSymbol will be declared by an enclosing block
statements: ImmutableArray.Create<BoundStatement>(
rewrittenDeclaration,
new BoundExpressionStatement(declarationSyntax, tempAssignment),
tryFinally));
}
else
{
BoundStatement tryFinally = RewriteUsingStatementTryFinally(usingSyntax, tryBlock, boundLocal);
// localSymbol will be declared by an enclosing block
return BoundBlock.SynthesizedNoLocals(usingSyntax, rewrittenDeclaration, tryFinally);
}
}
public override BoundNode VisitBlock(BoundBlock node)
{
return PossibleIteratorScope(node.LocalsOpt, () => (BoundStatement)base.VisitBlock(node));
}
internal BoundCatchBlock Catch(
BoundExpression source,
BoundBlock block)
{
return new BoundCatchBlock(Syntax, ImmutableArray<LocalSymbol>.Empty, source, source.Type, exceptionFilterOpt: null, body: block);
}
internal BoundStatement Try(
BoundBlock tryBlock,
ImmutableArray<BoundCatchBlock> catchBlocks,
BoundBlock finallyBlock = null)
{
return new BoundTryStatement(Syntax, tryBlock, catchBlocks, finallyBlock) { WasCompilerGenerated = true };
}
public override BoundStatement CreateBlockEpilogue(BoundBlock original)
{
var previous = base.CreateBlockEpilogue(original);
if (original.Syntax.Kind() == SyntaxKind.Block && !original.WasCompilerGenerated)
{
// no need to mark "}" on the outermost block
// as it cannot leave it normally. The block will have "return" at the end.
CSharpSyntaxNode parent = original.Syntax.Parent;
if (parent == null || !(parent.IsAnonymousFunction() || parent is BaseMethodDeclarationSyntax))
{
var cBspan = ((BlockSyntax)original.Syntax).CloseBraceToken.Span;
return new BoundSequencePointWithSpan(original.Syntax, previous, cBspan);
}
}
return previous;
}
private void VisitBlockInternal(BoundBlock node)
{
var previousBlock = PushBlock(node, node.Locals);
base.VisitBlock(node);
PopBlock(previousBlock);
}
/// <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)((int)SynthesizedLocalKind.ForEachArrayLimit0 + dimension));
boundUpperVar[dimension] = MakeBoundLocal(forEachSyntax, upperVar[dimension], intType);
ImmutableArray <BoundExpression> dimensionArgument = ImmutableArray.Create <BoundExpression>(
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)((int)SynthesizedLocalKind.ForEachArrayIndex0 + dimension));
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>((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 = new BoundBlock(forEachSyntax,
locals: ImmutableArray.Create <LocalSymbol>(iterationVar),
statements: ImmutableArray.Create <BoundStatement>(iterationVarDecl, rewrittenBody));
// 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 <BoundExpression>(
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 <LocalSymbol>(arrayVar).Concat(upperVar.AsImmutableOrNull()),
ImmutableArray.Create <BoundStatement>(arrayVarDecl).Concat(upperVarDecl.AsImmutableOrNull()).Add(forLoop));
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return(result);
}
/// <summary>
/// Generate a thread-safe accessor for a WinRT field-like event.
///
/// Add:
/// return EventRegistrationTokenTable<Event>.GetOrCreateEventRegistrationTokenTable(ref _tokenTable).AddEventHandler(value);
///
/// Remove:
/// EventRegistrationTokenTable<Event>.GetOrCreateEventRegistrationTokenTable(ref _tokenTable).RemoveEventHandler(value);
/// </summary>
internal static BoundBlock ConstructFieldLikeEventAccessorBody_WinRT(SourceEventSymbol eventSymbol, bool isAddMethod, CSharpCompilation compilation, DiagnosticBag diagnostics)
{
CSharpSyntaxNode syntax = eventSymbol.CSharpSyntaxNode;
MethodSymbol accessor = isAddMethod ? eventSymbol.AddMethod : eventSymbol.RemoveMethod;
Debug.Assert((object)accessor != null);
FieldSymbol field = eventSymbol.AssociatedField;
Debug.Assert((object)field != null);
NamedTypeSymbol fieldType = (NamedTypeSymbol)field.Type;
Debug.Assert(fieldType.Name == "EventRegistrationTokenTable");
MethodSymbol getOrCreateMethod = (MethodSymbol)Binder.GetWellKnownTypeMember(
compilation,
WellKnownMember.System_Runtime_InteropServices_WindowsRuntime_EventRegistrationTokenTable_T__GetOrCreateEventRegistrationTokenTable,
diagnostics,
syntax: syntax);
if ((object)getOrCreateMethod == null)
{
Debug.Assert(diagnostics.HasAnyErrors());
return(null);
}
getOrCreateMethod = getOrCreateMethod.AsMember(fieldType);
WellKnownMember processHandlerMember = isAddMethod
? WellKnownMember.System_Runtime_InteropServices_WindowsRuntime_EventRegistrationTokenTable_T__AddEventHandler
: WellKnownMember.System_Runtime_InteropServices_WindowsRuntime_EventRegistrationTokenTable_T__RemoveEventHandler;
MethodSymbol processHandlerMethod = (MethodSymbol)Binder.GetWellKnownTypeMember(
compilation,
processHandlerMember,
diagnostics,
syntax: syntax);
if ((object)processHandlerMethod == null)
{
Debug.Assert(diagnostics.HasAnyErrors());
return(null);
}
processHandlerMethod = processHandlerMethod.AsMember(fieldType);
// _tokenTable
BoundFieldAccess fieldAccess = new BoundFieldAccess(
syntax,
field.IsStatic ? null : new BoundThisReference(syntax, accessor.ThisParameter.Type),
field,
constantValueOpt: null)
{
WasCompilerGenerated = true
};
// EventRegistrationTokenTable<Event>.GetOrCreateEventRegistrationTokenTable(ref _tokenTable)
BoundCall getOrCreateCall = BoundCall.Synthesized(
syntax,
receiverOpt: null,
method: getOrCreateMethod,
arg0: fieldAccess);
// value
BoundParameter parameterAccess = new BoundParameter(
syntax,
accessor.Parameters[0]);
// EventRegistrationTokenTable<Event>.GetOrCreateEventRegistrationTokenTable(ref _tokenTable).AddHandler(value) // or RemoveHandler
BoundCall processHandlerCall = BoundCall.Synthesized(
syntax,
receiverOpt: getOrCreateCall,
method: processHandlerMethod,
arg0: parameterAccess);
if (isAddMethod)
{
// {
// return EventRegistrationTokenTable<Event>.GetOrCreateEventRegistrationTokenTable(ref _tokenTable).AddHandler(value);
// }
BoundStatement returnStatement = BoundReturnStatement.Synthesized(syntax, RefKind.None, processHandlerCall);
return(BoundBlock.SynthesizedNoLocals(syntax, returnStatement));
}
else
{
// {
// EventRegistrationTokenTable<Event>.GetOrCreateEventRegistrationTokenTable(ref _tokenTable).RemoveHandler(value);
// return;
// }
BoundStatement callStatement = new BoundExpressionStatement(syntax, processHandlerCall);
BoundStatement returnStatement = new BoundReturnStatement(syntax, RefKind.None, expressionOpt: null);
return(BoundBlock.SynthesizedNoLocals(syntax, callStatement, returnStatement));
}
}
/// <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 */
// }
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: ImmutableArray.Create <BoundStatement>(iterationVarDecl, rewrittenBody),
locals: ImmutableArray.Create <LocalSymbol>(iterationVar)),
breakLabel: node.BreakLabel,
continueLabel: node.ContinueLabel,
hasErrors: false);
BoundStatement result;
MethodSymbol disposeMethod;
if (enumeratorInfo.NeedsDisposeMethod && TryGetSpecialTypeMember(forEachSyntax, SpecialMember.System_IDisposable__Dispose, out disposeMethod))
{
Binder.ReportDiagnosticsIfObsolete(diagnostics, disposeMethod, forEachSyntax,
hasBaseReceiver: false,
containingMember: this.factory.CurrentMethod,
containingType: this.factory.CurrentClass,
location: enumeratorInfo.Location);
BoundBlock finallyBlockOpt;
var idisposableTypeSymbol = disposeMethod.ContainingType;
var conversions = new TypeConversions(this.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: this.compilation.GetSpecialType(SpecialType.System_Object),
@checked: false),
right: MakeLiteral(forEachSyntax,
constantValue: 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,
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: this.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);
}
/// <summary>
/// Generate a thread-safe accessor for a regular field-like event.
///
/// DelegateType tmp0 = _event; //backing field
/// DelegateType tmp1;
/// DelegateType tmp2;
/// do {
/// tmp1 = tmp0;
/// tmp2 = (DelegateType)Delegate.Combine(tmp1, value); //Remove for -=
/// tmp0 = Interlocked.CompareExchange<DelegateType>(ref _event, tmp2, tmp1);
/// } while ((object)tmp0 != (object)tmp1);
///
/// Note, if System.Threading.Interlocked.CompareExchange<T> is not available,
/// we emit the following code and mark the method Synchronized (unless it is a struct).
///
/// _event = (DelegateType)Delegate.Combine(_event, value); //Remove for -=
///
/// </summary>
internal static BoundBlock ConstructFieldLikeEventAccessorBody_Regular(SourceEventSymbol eventSymbol, bool isAddMethod, CSharpCompilation compilation, DiagnosticBag diagnostics)
{
CSharpSyntaxNode syntax = eventSymbol.CSharpSyntaxNode;
TypeSymbol delegateType = eventSymbol.Type;
MethodSymbol accessor = isAddMethod ? eventSymbol.AddMethod : eventSymbol.RemoveMethod;
ParameterSymbol thisParameter = accessor.ThisParameter;
TypeSymbol boolType = compilation.GetSpecialType(SpecialType.System_Boolean);
SpecialMember updateMethodId = isAddMethod ? SpecialMember.System_Delegate__Combine : SpecialMember.System_Delegate__Remove;
MethodSymbol updateMethod = (MethodSymbol)compilation.GetSpecialTypeMember(updateMethodId);
BoundStatement @return = new BoundReturnStatement(syntax,
refKind: RefKind.None,
expressionOpt: null)
{
WasCompilerGenerated = true
};
if (updateMethod == null)
{
MemberDescriptor memberDescriptor = SpecialMembers.GetDescriptor(updateMethodId);
diagnostics.Add(new CSDiagnostic(new CSDiagnosticInfo(ErrorCode.ERR_MissingPredefinedMember,
memberDescriptor.DeclaringTypeMetadataName,
memberDescriptor.Name),
syntax.Location));
return(BoundBlock.SynthesizedNoLocals(syntax, @return));
}
Binder.ReportUseSiteDiagnostics(updateMethod, diagnostics, syntax);
BoundThisReference fieldReceiver = eventSymbol.IsStatic ?
null :
new BoundThisReference(syntax, thisParameter.Type)
{
WasCompilerGenerated = true
};
BoundFieldAccess boundBackingField = new BoundFieldAccess(syntax,
receiver: fieldReceiver,
fieldSymbol: eventSymbol.AssociatedField,
constantValueOpt: null)
{
WasCompilerGenerated = true
};
BoundParameter boundParameter = new BoundParameter(syntax,
parameterSymbol: accessor.Parameters[0])
{
WasCompilerGenerated = true
};
BoundExpression delegateUpdate;
MethodSymbol compareExchangeMethod = (MethodSymbol)compilation.GetWellKnownTypeMember(WellKnownMember.System_Threading_Interlocked__CompareExchange_T);
if ((object)compareExchangeMethod == null)
{
// (DelegateType)Delegate.Combine(_event, value)
delegateUpdate = BoundConversion.SynthesizedNonUserDefined(syntax,
operand: BoundCall.Synthesized(syntax,
receiverOpt: null,
method: updateMethod,
arguments: ImmutableArray.Create <BoundExpression>(boundBackingField, boundParameter)),
conversion: Conversion.ExplicitReference,
type: delegateType);
// _event = (DelegateType)Delegate.Combine(_event, value);
BoundStatement eventUpdate = new BoundExpressionStatement(syntax,
expression: new BoundAssignmentOperator(syntax,
left: boundBackingField,
right: delegateUpdate,
type: delegateType)
{
WasCompilerGenerated = true
})
{
WasCompilerGenerated = true
};
return(BoundBlock.SynthesizedNoLocals(syntax,
statements: ImmutableArray.Create <BoundStatement>(
eventUpdate,
@return)));
}
compareExchangeMethod = compareExchangeMethod.Construct(ImmutableArray.Create <TypeSymbol>(delegateType));
Binder.ReportUseSiteDiagnostics(compareExchangeMethod, diagnostics, syntax);
GeneratedLabelSymbol loopLabel = new GeneratedLabelSymbol("loop");
const int numTemps = 3;
LocalSymbol[] tmps = new LocalSymbol[numTemps];
BoundLocal[] boundTmps = new BoundLocal[numTemps];
for (int i = 0; i < numTemps; i++)
{
tmps[i] = new SynthesizedLocal(accessor, TypeWithAnnotations.Create(delegateType), SynthesizedLocalKind.LoweringTemp);
boundTmps[i] = new BoundLocal(syntax, tmps[i], null, delegateType);
}
// tmp0 = _event;
BoundStatement tmp0Init = new BoundExpressionStatement(syntax,
expression: new BoundAssignmentOperator(syntax,
left: boundTmps[0],
right: boundBackingField,
type: delegateType)
{
WasCompilerGenerated = true
})
{
WasCompilerGenerated = true
};
// LOOP:
BoundStatement loopStart = new BoundLabelStatement(syntax,
label: loopLabel)
{
WasCompilerGenerated = true
};
// tmp1 = tmp0;
BoundStatement tmp1Update = new BoundExpressionStatement(syntax,
expression: new BoundAssignmentOperator(syntax,
left: boundTmps[1],
right: boundTmps[0],
type: delegateType)
{
WasCompilerGenerated = true
})
{
WasCompilerGenerated = true
};
// (DelegateType)Delegate.Combine(tmp1, value)
delegateUpdate = BoundConversion.SynthesizedNonUserDefined(syntax,
operand: BoundCall.Synthesized(syntax,
receiverOpt: null,
method: updateMethod,
arguments: ImmutableArray.Create <BoundExpression>(boundTmps[1], boundParameter)),
conversion: Conversion.ExplicitReference,
type: delegateType);
// tmp2 = (DelegateType)Delegate.Combine(tmp1, value);
BoundStatement tmp2Update = new BoundExpressionStatement(syntax,
expression: new BoundAssignmentOperator(syntax,
left: boundTmps[2],
right: delegateUpdate,
type: delegateType)
{
WasCompilerGenerated = true
})
{
WasCompilerGenerated = true
};
// Interlocked.CompareExchange<DelegateType>(ref _event, tmp2, tmp1)
BoundExpression compareExchange = BoundCall.Synthesized(syntax,
receiverOpt: null,
method: compareExchangeMethod,
arguments: ImmutableArray.Create <BoundExpression>(boundBackingField, boundTmps[2], boundTmps[1]));
// tmp0 = Interlocked.CompareExchange<DelegateType>(ref _event, tmp2, tmp1);
BoundStatement tmp0Update = new BoundExpressionStatement(syntax,
expression: new BoundAssignmentOperator(syntax,
left: boundTmps[0],
right: compareExchange,
type: delegateType)
{
WasCompilerGenerated = true
})
{
WasCompilerGenerated = true
};
// tmp0 == tmp1 // i.e. exit when they are equal, jump to start otherwise
BoundExpression loopExitCondition = new BoundBinaryOperator(syntax,
operatorKind: BinaryOperatorKind.ObjectEqual,
left: boundTmps[0],
right: boundTmps[1],
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: boolType)
{
WasCompilerGenerated = true
};
// branchfalse (tmp0 == tmp1) LOOP
BoundStatement loopEnd = new BoundConditionalGoto(syntax,
condition: loopExitCondition,
jumpIfTrue: false,
label: loopLabel)
{
WasCompilerGenerated = true
};
return(new BoundBlock(syntax,
locals: tmps.AsImmutable(),
statements: ImmutableArray.Create <BoundStatement>(
tmp0Init,
loopStart,
tmp1Update,
tmp2Update,
tmp0Update,
loopEnd,
@return))
{
WasCompilerGenerated = true
});
}
/// <summary>
/// The try statement is the most complex part of the state machine transformation.
/// Since the CLR will not allow a 'goto' into the scope of a try statement, we must
/// generate the dispatch to the state's label stepwise. That is done by translating
/// the try statements from the inside to the outside. Within a try statement, we
/// start with an empty dispatch table (representing the mapping from state numbers
/// to labels). During translation of the try statement's body, the dispatch table
/// will be filled in with the data necessary to dispatch once we're inside the try
/// block. We generate that at the head of the translated try statement. Then, we
/// copy all of the states from that table into the table for the enclosing construct,
/// but associate them with a label just before the translated try block. That way
/// the enclosing construct will generate the code necessary to get control into the
/// try block for all of those states.
/// </summary>
public override BoundNode VisitTryStatement(BoundTryStatement node)
{
var oldDispatches = _dispatches;
var oldFinalizerState = _currentFinalizerState;
var oldHasFinalizerState = _hasFinalizerState;
_dispatches = null;
_currentFinalizerState = -1;
_hasFinalizerState = false;
BoundBlock tryBlock = F.Block((BoundStatement)this.Visit(node.TryBlock));
GeneratedLabelSymbol dispatchLabel = null;
if (_dispatches != null)
{
dispatchLabel = F.GenerateLabel("tryDispatch");
if (_hasFinalizerState)
{
// cause the current finalizer state to arrive here and then "return false"
var finalizer = F.GenerateLabel("finalizer");
_dispatches.Add(finalizer, new List <int>()
{
_currentFinalizerState
});
var skipFinalizer = F.GenerateLabel("skipFinalizer");
tryBlock = F.Block(
F.HiddenSequencePoint(),
Dispatch(),
F.Goto(skipFinalizer),
F.Label(finalizer), // code for the finalizer here
GenerateSetBothStates(StateMachineStates.NotStartedStateMachine),
GenerateReturn(false),
F.Label(skipFinalizer),
tryBlock);
}
else
{
tryBlock = F.Block(
F.HiddenSequencePoint(),
Dispatch(),
tryBlock);
}
if (oldDispatches == null)
{
Debug.Assert(!oldHasFinalizerState);
oldDispatches = new Dictionary <LabelSymbol, List <int> >();
}
oldDispatches.Add(dispatchLabel, new List <int>(from kv in _dispatches.Values from n in kv orderby n select n));
}
_hasFinalizerState = oldHasFinalizerState;
_currentFinalizerState = oldFinalizerState;
_dispatches = oldDispatches;
ImmutableArray <BoundCatchBlock> catchBlocks = this.VisitList(node.CatchBlocks);
BoundBlock finallyBlockOpt = node.FinallyBlockOpt == null ? null : F.Block(
F.HiddenSequencePoint(),
F.If(
condition: F.IntLessThan(F.Local(cachedState), F.Literal(StateMachineStates.FirstUnusedState)),
thenClause: (BoundBlock)this.Visit(node.FinallyBlockOpt)
),
F.HiddenSequencePoint());
BoundStatement result = node.Update(tryBlock, catchBlocks, finallyBlockOpt, node.FinallyLabelOpt, node.PreferFaultHandler);
if ((object)dispatchLabel != null)
{
result = F.Block(
F.HiddenSequencePoint(),
F.Label(dispatchLabel),
result);
}
return(result);
}
public override BoundNode VisitBlock(BoundBlock node)
{
return(PossibleIteratorScope(node.Locals, () => (BoundStatement)base.VisitBlock(node)));
}
public override BoundNode VisitBlock(BoundBlock node)
{
AddVariables(node.Locals);
return(base.VisitBlock(node));
}
/// <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.ForEachArrayIndex0);
// 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 = new BoundBlock(forEachSyntax,
locals: ImmutableArray.Create <LocalSymbol>(iterationVar),
statements: ImmutableArray.Create <BoundStatement>(iterationVariableDecl, rewrittenBody));
// 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);
}
internal BoundTryStatement Fault(BoundBlock tryBlock, BoundBlock faultBlock)
{
return(new BoundTryStatement(Syntax, tryBlock, ImmutableArray <BoundCatchBlock> .Empty, faultBlock, preferFaultHandler: true));
}
/// <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.ForEachArrayIndex0);
// 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 = new BoundBlock(forEachSyntax,
locals: ImmutableArray.Create <LocalSymbol>(iterationVar),
statements: ImmutableArray.Create <BoundStatement>(iterationVarDecl, rewrittenBody));
// 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 BoundNode VisitBlock(BoundBlock node)
{
if (node.Locals.IsEmpty)
{
// ignore blocks that declare no variables.
return base.VisitBlock(node);
}
VisitBlockInternal(node);
return node;
}
/// <summary>
/// Lower "using (expression) statement" to a try-finally block.
/// </summary>
private BoundBlock RewriteExpressionUsingStatement(BoundUsingStatement node, BoundBlock tryBlock)
{
Debug.Assert(node.ExpressionOpt != null);
Debug.Assert(node.DeclarationsOpt == null);
// See comments in BuildUsingTryFinally for the details of the lowering to try-finally.
//
// SPEC: A using statement of the form "using (expression) statement; " has the
// SPEC: same three possible expansions [ as "using (ResourceType r = expression) statement; ]
// SPEC: but in this case ResourceType is implicitly the compile-time type of the expression,
// SPEC: and the resource variable is inaccessible to and invisible to the embedded statement.
//
// DELIBERATE SPEC VIOLATION:
//
// The spec quote above implies that the expression must have a type; in fact we allow
// the expression to be null.
//
// If expr is the constant null then we can elide the whole thing and simply generate the statement.
BoundExpression rewrittenExpression = (BoundExpression)Visit(node.ExpressionOpt);
if (rewrittenExpression.ConstantValue == ConstantValue.Null)
{
Debug.Assert(node.Locals.IsEmpty); // TODO: This might not be a valid assumption in presence of semicolon operator.
return tryBlock;
}
// Otherwise, we lower "using(expression) statement;" as follows:
//
// * If the expression is of type dynamic then we lower as though the user had written
//
// using(IDisposable temp = (IDisposable)expression) statement;
//
// Note that we have to do the conversion early, not in the finally block, because
// if the conversion fails at runtime with an exception then the exception must happen
// before the statement runs.
//
// * Otherwise we lower as though the user had written
//
// using(ResourceType temp = expression) statement;
//
TypeSymbol expressionType = rewrittenExpression.Type;
CSharpSyntaxNode expressionSyntax = rewrittenExpression.Syntax;
UsingStatementSyntax usingSyntax = (UsingStatementSyntax)node.Syntax;
BoundAssignmentOperator tempAssignment;
BoundLocal boundTemp;
if ((object)expressionType == null || expressionType.IsDynamic())
{
// IDisposable temp = (IDisposable) expr;
BoundExpression tempInit = MakeConversion(
expressionSyntax,
rewrittenExpression,
node.IDisposableConversion.Kind,
this.compilation.GetSpecialType(SpecialType.System_IDisposable),
@checked: false,
constantValueOpt: rewrittenExpression.ConstantValue);
boundTemp = this.factory.StoreToTemp(tempInit, out tempAssignment);
}
else
{
// ResourceType temp = expr;
boundTemp = this.factory.StoreToTemp(rewrittenExpression, out tempAssignment, kind: SynthesizedLocalKind.Using);
}
BoundStatement expressionStatement = new BoundExpressionStatement(expressionSyntax, tempAssignment);
if (this.generateDebugInfo)
{
expressionStatement = AddSequencePoint(usingSyntax, expressionStatement);
}
BoundStatement tryFinally = RewriteUsingStatementTryFinally(usingSyntax, tryBlock, boundTemp);
// { ResourceType temp = expr; try { ... } finally { ... } }
return new BoundBlock(
syntax: usingSyntax,
locals: node.Locals.Add(boundTemp.LocalSymbol),
statements: ImmutableArray.Create<BoundStatement>(expressionStatement, tryFinally));
}
public override BoundStatement CreateBlockPrologue(BoundBlock original, out Symbols.LocalSymbol synthesizedLocal)
{
var previous = base.CreateBlockPrologue(original, out synthesizedLocal);
if (original.Syntax.Kind() == SyntaxKind.Block && !original.WasCompilerGenerated)
{
var oBspan = ((BlockSyntax)original.Syntax).OpenBraceToken.Span;
return new BoundSequencePointWithSpan(original.Syntax, previous, oBspan);
}
else if (previous != null)
{
return new BoundSequencePoint(original.Syntax, previous);
}
return null;
}
internal BoundCatchBlock Catch(
BoundExpression source,
BoundBlock block)
{
return(new BoundCatchBlock(Syntax, ImmutableArray <LocalSymbol> .Empty, source, source.Type, exceptionFilterOpt: null, body: block));
}
internal BoundTryStatement Fault(BoundBlock tryBlock, BoundBlock faultBlock)
{
return new BoundTryStatement(Syntax, tryBlock, ImmutableArray<BoundCatchBlock>.Empty, faultBlock, preferFaultHandler: true);
}
/// <summary>
/// The flow analysis pass. This pass reports required diagnostics for unreachable
/// statements and uninitialized variables (through the call to FlowAnalysisWalker.Analyze),
/// and inserts a final return statement if the end of a void-returning method is reachable.
/// </summary>
/// <param name="method">the method to be analyzed</param>
/// <param name="block">the method's body</param>
/// <param name="diagnostics">the receiver of the reported diagnostics</param>
/// <param name="hasTrailingExpression">indicates whether this Script had a trailing expression</param>
/// <param name="originalBodyNested">the original method body is the last statement in the block</param>
/// <returns>the rewritten block for the method (with a return statement possibly inserted)</returns>
public static BoundBlock Rewrite(
MethodSymbol method,
BoundBlock block,
DiagnosticBag diagnostics,
bool hasTrailingExpression,
bool originalBodyNested)
{
#if DEBUG
// We should only see a trailingExpression if we're in a Script initializer.
Debug.Assert(!hasTrailingExpression || method.IsScriptInitializer);
var initialDiagnosticCount = diagnostics.ToReadOnly().Length;
#endif
var compilation = method.DeclaringCompilation;
if (method.ReturnsVoid || method.IsIterator || method.IsAsyncReturningTask(compilation))
{
// we don't analyze synthesized void methods.
if ((method.IsImplicitlyDeclared && !method.IsScriptInitializer) ||
Analyze(compilation, method, block, diagnostics))
{
block = AppendImplicitReturn(block, method, originalBodyNested);
}
}
else if (Analyze(compilation, method, block, diagnostics))
{
// If the method is a lambda expression being converted to a non-void delegate type
// and the end point is reachable then suppress the error here; a special error
// will be reported by the lambda binder.
Debug.Assert(method.MethodKind != MethodKind.AnonymousFunction);
// Add implicit "return default(T)" if this is a submission that does not have a trailing expression.
var submissionResultType = (method as SynthesizedInteractiveInitializerMethod)?.ResultType;
if (!hasTrailingExpression && ((object)submissionResultType != null))
{
Debug.Assert(!submissionResultType.IsVoidType());
var trailingExpression = new BoundDefaultExpression(method.GetNonNullSyntaxNode(), submissionResultType);
var newStatements = block.Statements.Add(new BoundReturnStatement(trailingExpression.Syntax, RefKind.None, trailingExpression));
block = new BoundBlock(block.Syntax, ImmutableArray <LocalSymbol> .Empty, newStatements)
{
WasCompilerGenerated = true
};
#if DEBUG
// It should not be necessary to repeat analysis after adding this node, because adding a trailing
// return in cases where one was missing should never produce different Diagnostics.
IEnumerable <Diagnostic> GetErrorsOnly(IEnumerable <Diagnostic> diags) => diags.Where(d => d.Severity == DiagnosticSeverity.Error);
var flowAnalysisDiagnostics = DiagnosticBag.GetInstance();
Debug.Assert(!Analyze(compilation, method, block, flowAnalysisDiagnostics));
// Ignore warnings since flow analysis reports nullability mismatches.
Debug.Assert(GetErrorsOnly(flowAnalysisDiagnostics.ToReadOnly()).SequenceEqual(GetErrorsOnly(diagnostics.ToReadOnly().Skip(initialDiagnosticCount))));
flowAnalysisDiagnostics.Free();
#endif
}
// If there's more than one location, then the method is partial and we
// have already reported a non-void partial method error.
else if (method.Locations.Length == 1)
{
diagnostics.Add(ErrorCode.ERR_ReturnExpected, method.Locations[0], method);
}
}
return(block);
}
internal BoundCatchBlock Catch(
LocalSymbol local,
BoundBlock block)
{
var source = Local(local);
return new BoundCatchBlock(Syntax, ImmutableArray.Create(local), source, source.Type, exceptionFilterOpt: null, body: block);
}
public BoundTryStatement(CSharpSyntaxNode syntax, BoundBlock tryBlock, ImmutableArray<BoundCatchBlock> catchBlocks, BoundBlock finallyBlockOpt)
: this(syntax, tryBlock, catchBlocks, finallyBlockOpt, preferFaultHandler: false, hasErrors: false)
{
}
// NOTE: can return null if the method has no body.
internal static BoundBlock BindMethodBody(MethodSymbol method, TypeCompilationState compilationState, DiagnosticBag diagnostics, bool generateDebugInfo, out ConsList<Imports> debugImports)
{
debugImports = null;
BoundStatement constructorInitializer = null;
BoundBlock body;
var compilation = method.DeclaringCompilation;
var sourceMethod = method as SourceMethodSymbol;
if ((object)sourceMethod != null)
{
if (sourceMethod.IsExtern)
{
if (sourceMethod.BlockSyntax == null)
{
// Generate warnings only if we are not generating ERR_ExternHasBody error
GenerateExternalMethodWarnings(sourceMethod, diagnostics);
}
return null;
}
else if (sourceMethod.IsParameterlessValueTypeConstructor(requireSynthesized: true))
{
// No body for default struct constructor.
return null;
}
var blockSyntax = sourceMethod.BlockSyntax;
if (blockSyntax != null)
{
var factory = compilation.GetBinderFactory(sourceMethod.SyntaxTree);
var inMethodBinder = factory.GetBinder(blockSyntax);
var binder = new ExecutableCodeBinder(blockSyntax, sourceMethod, inMethodBinder);
body = binder.BindBlock(blockSyntax, diagnostics);
if (generateDebugInfo)
{
debugImports = binder.ImportsList;
}
if (inMethodBinder.IsDirectlyInIterator)
{
foreach (var parameter in method.Parameters)
{
if (parameter.RefKind != RefKind.None)
{
diagnostics.Add(ErrorCode.ERR_BadIteratorArgType, parameter.Locations[0]);
}
else if (parameter.Type.IsUnsafe())
{
diagnostics.Add(ErrorCode.ERR_UnsafeIteratorArgType, parameter.Locations[0]);
}
}
if (sourceMethod.IsUnsafe && compilation.Options.AllowUnsafe) // Don't cascade
{
diagnostics.Add(ErrorCode.ERR_IllegalInnerUnsafe, sourceMethod.Locations[0]);
}
if (sourceMethod.IsVararg)
{
// error CS1636: __arglist is not allowed in the parameter list of iterators
diagnostics.Add(ErrorCode.ERR_VarargsIterator, sourceMethod.Locations[0]);
}
}
}
else // for [if (blockSyntax != null)]
{
var property = sourceMethod.AssociatedSymbol as SourcePropertySymbol;
if ((object)property != null && property.IsAutoProperty)
{
return MethodBodySynthesizer.ConstructAutoPropertyAccessorBody(sourceMethod);
}
if (sourceMethod.IsPrimaryCtor)
{
body = null;
}
else
{
return null;
}
}
}
else
{
// synthesized methods should return their bound bodies
body = null;
}
// delegates have constructors but not constructor initializers
if (method.MethodKind == MethodKind.Constructor && !method.ContainingType.IsDelegateType())
{
var initializerInvocation = BindConstructorInitializer(method, diagnostics, compilation);
if (initializerInvocation != null)
{
constructorInitializer = new BoundExpressionStatement(initializerInvocation.Syntax, initializerInvocation) { WasCompilerGenerated = true };
Debug.Assert(initializerInvocation.HasAnyErrors || constructorInitializer.IsConstructorInitializer(), "Please keep this bound node in sync with BoundNodeExtensions.IsConstructorInitializer.");
}
}
var statements = ArrayBuilder<BoundStatement>.GetInstance();
if (constructorInitializer != null)
{
statements.Add(constructorInitializer);
}
if ((object)sourceMethod != null && sourceMethod.IsPrimaryCtor && (object)((SourceMemberContainerTypeSymbol)sourceMethod.ContainingType).PrimaryCtor == (object)sourceMethod)
{
Debug.Assert(method.MethodKind == MethodKind.Constructor && !method.ContainingType.IsDelegateType());
Debug.Assert(body == null);
if (sourceMethod.ParameterCount > 0)
{
var factory = new SyntheticBoundNodeFactory(sourceMethod, sourceMethod.SyntaxNode, compilationState, diagnostics);
factory.CurrentMethod = sourceMethod;
foreach (var parameter in sourceMethod.Parameters)
{
FieldSymbol field = parameter.PrimaryConstructorParameterBackingField;
if ((object)field != null)
{
statements.Add(factory.Assignment(factory.Field(factory.This(), field),
factory.Parameter(parameter)));
}
}
}
}
if (body != null)
{
statements.Add(body);
}
CSharpSyntaxNode syntax = body != null ? body.Syntax : method.GetNonNullSyntaxNode();
BoundBlock block;
if (statements.Count == 1 && statements[0].Kind == ((body == null) ? BoundKind.Block : body.Kind))
{
// most common case - we just have a single block for the body.
block = (BoundBlock)statements[0];
statements.Free();
}
else
{
block = new BoundBlock(syntax, default(ImmutableArray<LocalSymbol>), statements.ToImmutableAndFree()) { WasCompilerGenerated = true };
}
return method.MethodKind == MethodKind.Destructor ? MethodBodySynthesizer.ConstructDestructorBody(syntax, method, block) : block;
}
// insert the implicit "return" statement at the end of the method body
// Normally, we wouldn't bother attaching syntax trees to compiler-generated nodes, but these
// ones are going to have sequence points.
internal static BoundBlock AppendImplicitReturn(BoundBlock body, MethodSymbol method, CSharpSyntaxNode syntax = null)
{
Debug.Assert(body != null);
Debug.Assert(method != null);
if (syntax == null)
{
syntax = body.Syntax;
}
Debug.Assert(body.WasCompilerGenerated || syntax.IsKind(SyntaxKind.Block) || syntax.IsKind(SyntaxKind.ArrowExpressionClause));
BoundStatement ret = method.IsIterator
? (BoundStatement)BoundYieldBreakStatement.Synthesized(syntax)
: BoundReturnStatement.Synthesized(syntax, RefKind.None, null);
return body.Update(body.Locals, body.LocalFunctions, body.Statements.Add(ret));
}
public override BoundNode VisitBlock(BoundBlock node)
{
AddVariables(node.Locals);
return base.VisitBlock(node);
}
private static bool Analyze(
CSharpCompilation compilation,
MethodSymbol method,
BoundBlock block,
DiagnosticBag diagnostics)
{
var result = ControlFlowPass.Analyze(compilation, method, block, diagnostics);
DataFlowPass.Analyze(compilation, method, block, diagnostics);
return result;
}
private BoundStatement RewriteUsingStatementTryFinally(CSharpSyntaxNode syntax, BoundBlock tryBlock, BoundLocal local)
{
// 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.
//
// 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.
BoundExpression disposedExpression;
bool isNullableValueType = local.Type.IsNullableType();
if (isNullableValueType)
{
MethodSymbol getValueOrDefault = GetNullableMethod(syntax, local.Type, SpecialMember.System_Nullable_T_GetValueOrDefault);
// local.GetValueOrDefault()
disposedExpression = BoundCall.Synthesized(syntax, local, getValueOrDefault);
}
else
{
// local
disposedExpression = local;
}
// local.Dispose()
BoundExpression disposeCall;
MethodSymbol disposeMethodSymbol;
if (TryGetSpecialTypeMember(syntax, SpecialMember.System_IDisposable__Dispose, out disposeMethodSymbol))
{
disposeCall = BoundCall.Synthesized(syntax, disposedExpression, disposeMethodSymbol);
}
else
{
disposeCall = new BoundBadExpression(syntax, LookupResultKind.NotInvocable, ImmutableArray<Symbol>.Empty, ImmutableArray.Create<BoundNode>(disposedExpression), ErrorTypeSymbol.UnknownResultType);
}
// local.Dispose();
BoundStatement disposeStatement = new BoundExpressionStatement(syntax, disposeCall);
BoundExpression ifCondition;
if (isNullableValueType)
{
MethodSymbol hasValue = GetNullableMethod(syntax, local.Type, SpecialMember.System_Nullable_T_get_HasValue);
// local.HasValue
ifCondition = BoundCall.Synthesized(syntax, local, hasValue);
}
else if (local.Type.IsValueType)
{
ifCondition = null;
}
else
{
// local != null
ifCondition = MakeNullCheck(syntax, local, BinaryOperatorKind.NotEqual);
}
BoundStatement finallyStatement;
if (ifCondition == null)
{
// local.Dispose();
finallyStatement = disposeStatement;
}
else
{
// if (local != null) local.Dispose();
// or
// if (local.HasValue) local.GetValueOrDefault().Dispose();
finallyStatement = RewriteIfStatement(
syntax: syntax,
locals: ImmutableArray<LocalSymbol>.Empty,
rewrittenCondition: ifCondition,
rewrittenConsequence: disposeStatement,
rewrittenAlternativeOpt: null,
hasErrors: false);
}
// try { ... } finally { if (local != null) local.Dispose(); }
BoundStatement tryFinally = new BoundTryStatement(
syntax: syntax,
tryBlock: tryBlock,
catchBlocks: ImmutableArray<BoundCatchBlock>.Empty,
finallyBlockOpt: BoundBlock.SynthesizedNoLocals(syntax, finallyStatement));
return tryFinally;
}
internal static BoundBlock ConstructDestructorBody(MethodSymbol method, BoundBlock block)
{
var syntax = block.Syntax;
Debug.Assert(method.MethodKind == MethodKind.Destructor);
Debug.Assert(syntax.Kind() == SyntaxKind.Block || syntax.Kind() == SyntaxKind.ArrowExpressionClause);
// If this is a destructor and a base type has a Finalize method (see GetBaseTypeFinalizeMethod for exact
// requirements), then we need to call that method in a finally block. Otherwise, just return block as-is.
// NOTE: the Finalize method need not be a destructor or be overridden by the current method.
MethodSymbol baseTypeFinalize = GetBaseTypeFinalizeMethod(method);
if ((object)baseTypeFinalize != null)
{
BoundStatement baseFinalizeCall = new BoundExpressionStatement(
syntax,
BoundCall.Synthesized(
syntax,
new BoundBaseReference(
syntax,
method.ContainingType)
{
WasCompilerGenerated = true
},
baseTypeFinalize))
{
WasCompilerGenerated = true
};
if (syntax.Kind() == SyntaxKind.Block)
{
//sequence point to mimic Dev10
baseFinalizeCall = new BoundSequencePointWithSpan(
syntax,
baseFinalizeCall,
((BlockSyntax)syntax).CloseBraceToken.Span);
}
return(new BoundBlock(
syntax,
ImmutableArray <LocalSymbol> .Empty,
ImmutableArray.Create <BoundStatement>(
new BoundTryStatement(
syntax,
block,
ImmutableArray <BoundCatchBlock> .Empty,
new BoundBlock(
syntax,
ImmutableArray <LocalSymbol> .Empty,
ImmutableArray.Create <BoundStatement>(
baseFinalizeCall)
)
{
WasCompilerGenerated = true
}
)
{
WasCompilerGenerated = true
})));
}
return(block);
}
private BoundExpression TranslateLambdaBody(BoundBlock block)
{
Debug.Assert(block.Locals.IsEmpty);
foreach (var s in block.Statements)
{
for (var stmt = s; stmt != null;)
{
switch (stmt.Kind)
{
case BoundKind.ReturnStatement:
var result = Visit(((BoundReturnStatement)stmt).ExpressionOpt);
if (result != null)
{
return result;
}
stmt = null;
break;
case BoundKind.ExpressionStatement:
return Visit(((BoundExpressionStatement)stmt).Expression);
case BoundKind.SequencePoint:
stmt = ((BoundSequencePoint)stmt).StatementOpt;
break;
case BoundKind.SequencePointWithSpan:
stmt = ((BoundSequencePointWithSpan)stmt).StatementOpt;
break;
default:
throw ExceptionUtilities.UnexpectedValue(stmt.Kind);
}
}
}
return null;
}
public BoundTryStatement(SyntaxNode syntax, BoundBlock tryBlock, ImmutableArray <BoundCatchBlock> catchBlocks, BoundBlock finallyBlockOpt)
: this(syntax, tryBlock, catchBlocks, finallyBlockOpt, preferFaultHandler : false, hasErrors : false)
{
}