/// <summary>
/// Lowers a lock statement to a try-finally block that calls Monitor.Enter and Monitor.Exit
/// before and after the body, respectively.
/// </summary>
public override BoundNode VisitLockStatement(BoundLockStatement node)
{
LockStatementSyntax lockSyntax = (LockStatementSyntax)node.Syntax;
BoundExpression rewrittenArgument = VisitExpression(node.Argument);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
TypeSymbol argumentType = rewrittenArgument.Type;
if ((object)argumentType == null)
{
// This isn't particularly elegant, but hopefully locking on null is
// not very common.
Debug.Assert(rewrittenArgument.ConstantValue == ConstantValue.Null);
argumentType = _compilation.GetSpecialType(SpecialType.System_Object);
rewrittenArgument = MakeLiteral(
rewrittenArgument.Syntax,
rewrittenArgument.ConstantValue,
argumentType); //need to have a non-null type here for TempHelpers.StoreToTemp.
}
BoundAssignmentOperator assignmentToLockTemp;
BoundLocal boundLockTemp = _factory.StoreToTemp(rewrittenArgument, out assignmentToLockTemp, syntaxOpt: lockSyntax, kind: SynthesizedLocalKind.Lock);
BoundStatement boundLockTempInit = new BoundExpressionStatement(lockSyntax, assignmentToLockTemp);
BoundExpression exitCallExpr;
MethodSymbol exitMethod;
if (TryGetWellKnownTypeMember(lockSyntax, WellKnownMember.System_Threading_Monitor__Exit, out exitMethod))
{
exitCallExpr = BoundCall.Synthesized(
lockSyntax,
null,
exitMethod,
boundLockTemp);
}
else
{
exitCallExpr = new BoundBadExpression(lockSyntax, LookupResultKind.NotInvocable, ImmutableArray <Symbol> .Empty, ImmutableArray.Create <BoundExpression>(boundLockTemp), ErrorTypeSymbol.UnknownResultType);
}
BoundStatement exitCall = new BoundExpressionStatement(lockSyntax, exitCallExpr);
MethodSymbol enterMethod;
if ((TryGetWellKnownTypeMember(lockSyntax, WellKnownMember.System_Threading_Monitor__Enter2, out enterMethod, isOptional: true) ||
TryGetWellKnownTypeMember(lockSyntax, WellKnownMember.System_Threading_Monitor__Enter, out enterMethod)) && // If we didn't find the overload introduced in .NET 4.0, then use the older one.
enterMethod.ParameterCount == 2)
{
// C# 4.0+ version
// L $lock = `argument`; // sequence point
// bool $lockTaken = false;
// try
// {
// Monitor.Enter($lock, ref $lockTaken);
// `body` // sequence point
// }
// finally
// { // hidden sequence point
// if ($lockTaken) Monitor.Exit($lock);
// }
TypeSymbol boolType = _compilation.GetSpecialType(SpecialType.System_Boolean);
BoundAssignmentOperator assignmentToLockTakenTemp;
BoundLocal boundLockTakenTemp = _factory.StoreToTemp(
MakeLiteral(rewrittenArgument.Syntax, ConstantValue.False, boolType),
store: out assignmentToLockTakenTemp,
syntaxOpt: lockSyntax,
kind: SynthesizedLocalKind.LockTaken);
BoundStatement boundLockTakenTempInit = new BoundExpressionStatement(lockSyntax, assignmentToLockTakenTemp);
BoundStatement enterCall = new BoundExpressionStatement(
lockSyntax,
BoundCall.Synthesized(
lockSyntax,
null,
enterMethod,
boundLockTemp,
boundLockTakenTemp));
exitCall = RewriteIfStatement(
lockSyntax,
boundLockTakenTemp,
exitCall,
null,
node.HasErrors);
return(new BoundBlock(
lockSyntax,
ImmutableArray.Create(boundLockTemp.LocalSymbol, boundLockTakenTemp.LocalSymbol),
ImmutableArray.Create(
InstrumentLockTargetCapture(node, boundLockTempInit),
boundLockTakenTempInit,
new BoundTryStatement(
lockSyntax,
BoundBlock.SynthesizedNoLocals(lockSyntax, ImmutableArray.Create(
enterCall,
rewrittenBody)),
ImmutableArray <BoundCatchBlock> .Empty,
BoundBlock.SynthesizedNoLocals(lockSyntax,
exitCall)))));
}
else
{
// Pre-4.0 version
// L $lock = `argument`; // sequence point
// Monitor.Enter($lock); // NB: before try-finally so we don't Exit if an exception prevents us from acquiring the lock.
// try
// {
// `body` // sequence point
// }
// finally
// {
// Monitor.Exit($lock); // hidden sequence point
// }
BoundExpression enterCallExpr;
if ((object)enterMethod != null)
{
Debug.Assert(enterMethod.ParameterCount == 1);
enterCallExpr = BoundCall.Synthesized(
lockSyntax,
null,
enterMethod,
boundLockTemp);
}
else
{
enterCallExpr = new BoundBadExpression(lockSyntax, LookupResultKind.NotInvocable, ImmutableArray <Symbol> .Empty, ImmutableArray.Create <BoundExpression>(boundLockTemp), ErrorTypeSymbol.UnknownResultType);
}
BoundStatement enterCall = new BoundExpressionStatement(
lockSyntax,
enterCallExpr);
return(new BoundBlock(
lockSyntax,
ImmutableArray.Create(boundLockTemp.LocalSymbol),
ImmutableArray.Create(
InstrumentLockTargetCapture(node, boundLockTempInit),
enterCall,
new BoundTryStatement(
lockSyntax,
BoundBlock.SynthesizedNoLocals(lockSyntax, rewrittenBody),
ImmutableArray <BoundCatchBlock> .Empty,
BoundBlock.SynthesizedNoLocals(lockSyntax, exitCall)))));
}
}
private BoundExpression MakeEventAccess(
SyntaxNode syntax,
BoundExpression rewrittenReceiver,
EventSymbol eventSymbol,
ConstantValue constantValueOpt,
LookupResultKind resultKind,
TypeSymbol type)
{
Debug.Assert(eventSymbol.HasAssociatedField);
FieldSymbol fieldSymbol = eventSymbol.AssociatedField;
Debug.Assert((object)fieldSymbol != null);
if (!eventSymbol.IsWindowsRuntimeEvent)
{
return(MakeFieldAccess(syntax, rewrittenReceiver, fieldSymbol, constantValueOpt, resultKind, type));
}
NamedTypeSymbol fieldType = (NamedTypeSymbol)fieldSymbol.Type.TypeSymbol;
Debug.Assert(fieldType.Name == "EventRegistrationTokenTable");
// _tokenTable
BoundFieldAccess fieldAccess = new BoundFieldAccess(
syntax,
fieldSymbol.IsStatic ? null : rewrittenReceiver,
fieldSymbol,
constantValueOpt: null)
{
WasCompilerGenerated = true
};
BoundExpression getOrCreateCall;
MethodSymbol getOrCreateMethod;
if (TryGetWellKnownTypeMember(syntax, WellKnownMember.System_Runtime_InteropServices_WindowsRuntime_EventRegistrationTokenTable_T__GetOrCreateEventRegistrationTokenTable, out getOrCreateMethod))
{
getOrCreateMethod = getOrCreateMethod.AsMember(fieldType);
// EventRegistrationTokenTable<Event>.GetOrCreateEventRegistrationTokenTable(ref _tokenTable)
getOrCreateCall = BoundCall.Synthesized(
syntax,
receiverOpt: null,
method: getOrCreateMethod,
arg0: fieldAccess);
}
else
{
getOrCreateCall = new BoundBadExpression(syntax, LookupResultKind.NotInvocable, ImmutableArray <Symbol> .Empty, ImmutableArray.Create <BoundExpression>(fieldAccess), ErrorTypeSymbol.UnknownResultType);
}
PropertySymbol invocationListProperty;
if (TryGetWellKnownTypeMember(syntax, WellKnownMember.System_Runtime_InteropServices_WindowsRuntime_EventRegistrationTokenTable_T__InvocationList, out invocationListProperty))
{
MethodSymbol invocationListAccessor = invocationListProperty.GetMethod;
if ((object)invocationListAccessor == null)
{
string accessorName = SourcePropertyAccessorSymbol.GetAccessorName(invocationListProperty.Name,
getNotSet: true,
isWinMdOutput: invocationListProperty.IsCompilationOutputWinMdObj());
_diagnostics.Add(new CSDiagnosticInfo(ErrorCode.ERR_MissingPredefinedMember, invocationListProperty.ContainingType, accessorName), syntax.Location);
}
else
{
invocationListAccessor = invocationListAccessor.AsMember(fieldType);
return(_factory.Call(getOrCreateCall, invocationListAccessor));
}
}
return(new BoundBadExpression(syntax, LookupResultKind.NotInvocable, ImmutableArray <Symbol> .Empty, ImmutableArray.Create(getOrCreateCall), ErrorTypeSymbol.UnknownResultType));
}
