/// <summary>
/// Lower a foreach loop that will enumerate the characters of a string.
///
/// string s = x;
/// for (int p = 0; p < s.Length; p = p + 1) {
/// V v = (V)s.Chars[p];
/// // body
/// }
/// </summary>
/// <remarks>
/// We will follow Dev10 in diverging from the C# 4 spec by ignoring string's
/// implementation of IEnumerable and just indexing into its characters.
///
/// NOTE: We're assuming that sequence points have already been generated.
/// Otherwise, lowering to for-loops would generated spurious ones.
/// </remarks>
private BoundStatement RewriteStringForEachStatement(BoundForEachStatement node)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)node.Syntax;
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
TypeSymbol stringType = collectionExpression.Type;
Debug.Assert(stringType.SpecialType == SpecialType.System_String);
TypeSymbol intType = compilation.GetSpecialType(SpecialType.System_Int32);
TypeSymbol boolType = compilation.GetSpecialType(SpecialType.System_Boolean);
BoundExpression rewrittenExpression = (BoundExpression)Visit(collectionExpression);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
// string s;
LocalSymbol stringVar = factory.SynthesizedLocal(stringType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArray);
// int p;
LocalSymbol positionVar = factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayIndex);
// Reference to s.
BoundLocal boundStringVar = MakeBoundLocal(forEachSyntax, stringVar, stringType);
// Reference to p.
BoundLocal boundPositionVar = MakeBoundLocal(forEachSyntax, positionVar, intType);
// string s = /*expr*/;
BoundStatement stringVarDecl = MakeLocalDeclaration(forEachSyntax, stringVar, rewrittenExpression);
AddForEachExpressionSequencePoint(forEachSyntax, ref stringVarDecl);
// int p = 0;
BoundStatement positionVariableDecl = MakeLocalDeclaration(forEachSyntax, positionVar,
MakeLiteral(forEachSyntax, ConstantValue.Default(SpecialType.System_Int32), intType));
// string s = /*node.Expression*/; int p = 0;
BoundStatement initializer = new BoundStatementList(forEachSyntax,
statements: ImmutableArray.Create <BoundStatement>(stringVarDecl, positionVariableDecl));
MethodSymbol method = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_String__Length);
BoundExpression stringLength = BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundStringVar,
method: method,
arguments: ImmutableArray <BoundExpression> .Empty);
// p < s.Length
BoundExpression exitCondition = new BoundBinaryOperator(
syntax: forEachSyntax,
operatorKind: BinaryOperatorKind.IntLessThan,
left: boundPositionVar,
right: stringLength,
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: boolType);
// p = p + 1;
BoundStatement positionIncrement = MakePositionIncrement(forEachSyntax, boundPositionVar, intType);
LocalSymbol iterationVar = node.IterationVariable;
TypeSymbol iterationVarType = iterationVar.Type;
Debug.Assert(node.ElementConversion.IsValid);
// (V)s.Chars[p]
MethodSymbol chars = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_String__Chars);
BoundExpression iterationVarInitValue = MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: BoundCall.Synthesized(
syntax: forEachSyntax,
receiverOpt: boundStringVar,
method: chars,
arguments: ImmutableArray.Create <BoundExpression>(boundPositionVar)),
conversion: node.ElementConversion,
rewrittenType: iterationVarType,
@checked: node.Checked);
// V v = (V)s.Chars[p];
BoundStatement iterationVarDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarInitValue);
AddForEachIterationVariableSequencePoint(forEachSyntax, ref iterationVarDecl);
// { V v = (V)s.Chars[p]; /*node.Body*/ }
BoundStatement loopBody = 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);
}
/// <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)
{
WasCompilerGenerated = true
};
}
// 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
});
}
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 MakeUnaryOperator(
BoundUnaryOperator oldNode,
UnaryOperatorKind kind,
CSharpSyntaxNode syntax,
MethodSymbol method,
BoundExpression loweredOperand,
TypeSymbol type)
{
if (kind.IsDynamic())
{
Debug.Assert(kind == UnaryOperatorKind.DynamicTrue && type.SpecialType == SpecialType.System_Boolean || type.IsDynamic());
Debug.Assert((object)method == null);
// Logical operators on boxed Boolean constants:
var constant = UnboxConstant(loweredOperand);
if (constant == ConstantValue.True || constant == ConstantValue.False)
{
if (kind == UnaryOperatorKind.DynamicTrue)
{
return(_factory.Literal(constant.BooleanValue));
}
else if (kind == UnaryOperatorKind.DynamicLogicalNegation)
{
return(MakeConversion(_factory.Literal(!constant.BooleanValue), type, @checked: false));
}
}
return(_dynamicFactory.MakeDynamicUnaryOperator(kind, loweredOperand, type).ToExpression());
}
else if (kind.IsLifted())
{
if (!_inExpressionLambda)
{
return(LowerLiftedUnaryOperator(kind, syntax, method, loweredOperand, type));
}
}
else if (kind.IsUserDefined())
{
Debug.Assert((object)method != null);
Debug.Assert(type == method.ReturnType);
if (!_inExpressionLambda || kind == UnaryOperatorKind.UserDefinedTrue || kind == UnaryOperatorKind.UserDefinedFalse)
{
return(BoundCall.Synthesized(syntax, null, method, loweredOperand));
}
}
else if (kind.Operator() == UnaryOperatorKind.UnaryPlus)
{
// We do not call the operator even for decimal; we simply optimize it away entirely.
return(loweredOperand);
}
if (kind == UnaryOperatorKind.EnumBitwiseComplement)
{
var underlyingType = loweredOperand.Type.GetEnumUnderlyingType();
var upconvertSpecialType = Binder.GetEnumPromotedType(underlyingType.SpecialType);
var upconvertType = upconvertSpecialType == underlyingType.SpecialType ?
underlyingType :
_compilation.GetSpecialType(upconvertSpecialType);
var newOperand = MakeConversion(loweredOperand, upconvertType, false);
UnaryOperatorKind newKind = kind.Operator().WithType(upconvertSpecialType);
var newNode = (oldNode != null) ?
oldNode.Update(
newKind,
newOperand,
oldNode.ConstantValueOpt,
method,
newOperand.ResultKind,
upconvertType) :
new BoundUnaryOperator(
syntax,
newKind,
newOperand,
null,
method,
LookupResultKind.Viable,
upconvertType);
return(MakeConversion(newNode.Syntax, newNode, ConversionKind.ExplicitEnumeration, type, @checked: false));
}
if (kind == UnaryOperatorKind.DecimalUnaryMinus)
{
method = (MethodSymbol)_compilation.Assembly.GetSpecialTypeMember(SpecialMember.System_Decimal__op_UnaryNegation);
if (!_inExpressionLambda)
{
return(BoundCall.Synthesized(syntax, null, method, loweredOperand));
}
}
return((oldNode != null) ?
oldNode.Update(kind, loweredOperand, oldNode.ConstantValueOpt, method, oldNode.ResultKind, type) :
new BoundUnaryOperator(syntax, kind, loweredOperand, null, method, LookupResultKind.Viable, type));
}
private BoundExpression MakeEventAccess(
CSharpSyntaxNode 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;
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 <BoundNode>(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 <BoundNode>(getOrCreateCall), ErrorTypeSymbol.UnknownResultType));
}
private BoundStatement RewriteUsingStatementTryFinally(SyntaxNode syntax, BoundBlock tryBlock, BoundLocal local, SyntaxToken awaitKeywordOpt, BoundAwaitableInfo awaitOpt, MethodSymbol methodOpt)
{
// 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.
//
// In the case of using-await statement, we'll use "IAsyncDisposable" instead of "IDisposable", "await DisposeAsync()" instead of "Dispose()"
//
// 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.
Debug.Assert((awaitKeywordOpt == default) == (awaitOpt is null));
BoundExpression disposedExpression;
bool isNullableValueType = local.Type.IsNullableType();
if (isNullableValueType)
{
MethodSymbol getValueOrDefault = UnsafeGetNullableMethod(syntax, local.Type, SpecialMember.System_Nullable_T_GetValueOrDefault);
// local.GetValueOrDefault()
disposedExpression = BoundCall.Synthesized(syntax, local, getValueOrDefault);
}
else
{
// local
disposedExpression = local;
}
BoundExpression disposeCall = GenerateDisposeCall(syntax, disposedExpression, methodOpt, awaitOpt, awaitKeywordOpt);
// local.Dispose(); or await variant
BoundStatement disposeStatement = new BoundExpressionStatement(syntax, disposeCall);
BoundExpression ifCondition;
if (isNullableValueType)
{
// local.HasValue
ifCondition = MakeNullableHasValue(syntax, local);
}
else if (local.Type.IsValueType)
{
ifCondition = null;
}
else
{
// local != null
ifCondition = MakeNullCheck(syntax, local, BinaryOperatorKind.NotEqual);
}
BoundStatement finallyStatement;
if (ifCondition == null)
{
// local.Dispose(); or await variant
finallyStatement = disposeStatement;
}
else
{
// if (local != null) local.Dispose();
// or
// if (local.HasValue) local.GetValueOrDefault().Dispose();
// or
// await variants
finallyStatement = RewriteIfStatement(
syntax: syntax,
rewrittenCondition: ifCondition,
rewrittenConsequence: disposeStatement,
rewrittenAlternativeOpt: null,
hasErrors: false);
}
// try { ... } finally { if (local != null) local.Dispose(); }
// or
// nullable or await variants
BoundStatement tryFinally = new BoundTryStatement(
syntax: syntax,
tryBlock: tryBlock,
catchBlocks: ImmutableArray <BoundCatchBlock> .Empty,
finallyBlockOpt: BoundBlock.SynthesizedNoLocals(syntax, finallyStatement));
return(tryFinally);
}
private BoundExpression MakePropertyAssignment(
SyntaxNode syntax,
BoundExpression rewrittenReceiver,
PropertySymbol property,
ImmutableArray <BoundExpression> rewrittenArguments,
ImmutableArray <RefKind> argumentRefKindsOpt,
bool expanded,
ImmutableArray <int> argsToParamsOpt,
BoundExpression rewrittenRight,
TypeSymbol type,
bool used)
{
// Rewrite property assignment into call to setter.
var setMethod = property.GetOwnOrInheritedSetMethod();
if ((object)setMethod == null)
{
Debug.Assert((property as SourcePropertySymbol)?.IsAutoProperty == true,
"only autoproperties can be assignable without having setters");
var backingField = (property as SourcePropertySymbol).BackingField;
return(_factory.AssignmentExpression(
_factory.Field(rewrittenReceiver, backingField),
rewrittenRight));
}
#if XSHARP
if (property is XsVariableSymbol xsvar)
{
return(MemVarFieldAssign(syntax, xsvar, rewrittenRight));
}
#endif
// We have already lowered each argument, but we may need some additional rewriting for the arguments,
// such as generating a params array, re-ordering arguments based on argsToParamsOpt map, inserting arguments for optional parameters, etc.
ImmutableArray <LocalSymbol> argTemps;
rewrittenArguments = MakeArguments(syntax, rewrittenArguments, property, setMethod, expanded, argsToParamsOpt, ref argumentRefKindsOpt, out argTemps, enableCallerInfo: ThreeState.True);
if (used)
{
// Save expression value to a temporary before calling the
// setter, and restore the temporary after the setter, so the
// assignment can be used as an embedded expression.
TypeSymbol exprType = rewrittenRight.Type;
LocalSymbol rhsTemp = _factory.SynthesizedLocal(exprType);
BoundExpression boundRhs = new BoundLocal(syntax, rhsTemp, null, exprType);
BoundExpression rhsAssignment = new BoundAssignmentOperator(
syntax,
boundRhs,
rewrittenRight,
exprType);
BoundExpression setterCall = BoundCall.Synthesized(
syntax,
rewrittenReceiver,
setMethod,
#if XSHARP
setMethod.IsAccessor() ? AppendToPossibleNull(rewrittenArguments, rhsAssignment) :
rewrittenArguments.NullToEmpty().Insert(0, rhsAssignment));
#else
AppendToPossibleNull(rewrittenArguments, rhsAssignment));
#endif
return(new BoundSequence(
syntax,
AppendToPossibleNull(argTemps, rhsTemp),
ImmutableArray.Create(setterCall),
boundRhs,
type));
}
else
{
BoundCall setterCall = BoundCall.Synthesized(
syntax,
rewrittenReceiver,
setMethod,
#if XSHARP
setMethod.IsAccessor() ? AppendToPossibleNull(rewrittenArguments, rewrittenRight) :
rewrittenArguments.NullToEmpty().Insert(0, rewrittenRight));
#else
AppendToPossibleNull(rewrittenArguments, rewrittenRight));
#endif
if (argTemps.IsDefaultOrEmpty)
{
return(setterCall);
}
else
{
return(new BoundSequence(
syntax,
argTemps,
ImmutableArray <BoundExpression> .Empty,
setterCall,
setMethod.ReturnType));
}
}
}
private BoundExpression MakeUnaryOperator(
BoundUnaryOperator oldNode,
UnaryOperatorKind kind,
CSharpSyntaxNode syntax,
MethodSymbol method,
BoundExpression loweredOperand,
TypeSymbol type)
{
if (kind.IsDynamic())
{
Debug.Assert(kind == UnaryOperatorKind.DynamicTrue && type.SpecialType == SpecialType.System_Boolean || type.IsDynamic());
Debug.Assert((object)method == null);
// Logical operators on boxed Boolean constants:
var constant = UnboxConstant(loweredOperand);
if (constant == ConstantValue.True || constant == ConstantValue.False)
{
if (kind == UnaryOperatorKind.DynamicTrue)
{
return(_factory.Literal(constant.BooleanValue));
}
else if (kind == UnaryOperatorKind.DynamicLogicalNegation)
{
return(MakeConversionNode(_factory.Literal(!constant.BooleanValue), type, @checked: false));
}
}
return(_dynamicFactory.MakeDynamicUnaryOperator(kind, loweredOperand, type).ToExpression());
}
else if (kind.IsLifted())
{
if (!_inExpressionLambda)
{
return(LowerLiftedUnaryOperator(kind, syntax, method, loweredOperand, type));
}
}
else if (kind.IsUserDefined())
{
Debug.Assert((object)method != null);
Debug.Assert(type == method.ReturnType);
if (!_inExpressionLambda || kind == UnaryOperatorKind.UserDefinedTrue || kind == UnaryOperatorKind.UserDefinedFalse)
{
// @t-mawind
// As usual, concept accesses need to be rewritten down to their
// default() form.
// Is this correct? It's mostly a copy over from the binary case,
// but the unary case is different enough to make me nervous.
if (method is SynthesizedWitnessMethodSymbol)
{
return(BoundCall.Synthesized(syntax, SynthesizeWitnessInvocationReceiver(syntax, ((SynthesizedWitnessMethodSymbol)method).Parent), method, loweredOperand));
}
return(BoundCall.Synthesized(syntax, null, method, loweredOperand));
}
}
else if (kind.Operator() == UnaryOperatorKind.UnaryPlus)
{
// We do not call the operator even for decimal; we simply optimize it away entirely.
return(loweredOperand);
}
if (kind == UnaryOperatorKind.EnumBitwiseComplement)
{
var underlyingType = loweredOperand.Type.GetEnumUnderlyingType();
var upconvertSpecialType = Binder.GetEnumPromotedType(underlyingType.SpecialType);
var upconvertType = upconvertSpecialType == underlyingType.SpecialType ?
underlyingType :
_compilation.GetSpecialType(upconvertSpecialType);
var newOperand = MakeConversionNode(loweredOperand, upconvertType, false);
UnaryOperatorKind newKind = kind.Operator().WithType(upconvertSpecialType);
var newNode = (oldNode != null) ?
oldNode.Update(
newKind,
newOperand,
oldNode.ConstantValueOpt,
method,
newOperand.ResultKind,
upconvertType) :
new BoundUnaryOperator(
syntax,
newKind,
newOperand,
null,
method,
LookupResultKind.Viable,
upconvertType);
return(MakeConversionNode(newNode.Syntax, newNode, Conversion.ExplicitEnumeration, type, @checked: false));
}
if (kind == UnaryOperatorKind.DecimalUnaryMinus)
{
method = (MethodSymbol)_compilation.Assembly.GetSpecialTypeMember(SpecialMember.System_Decimal__op_UnaryNegation);
if (!_inExpressionLambda)
{
return(BoundCall.Synthesized(syntax, null, method, loweredOperand));
}
}
return((oldNode != null) ?
oldNode.Update(kind, loweredOperand, oldNode.ConstantValueOpt, method, oldNode.ResultKind, type) :
new BoundUnaryOperator(syntax, kind, loweredOperand, null, method, LookupResultKind.Viable, type));
}
/// <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 = this.compilation.GetSpecialType(SpecialType.System_Object);
rewrittenArgument = MakeLiteral(
rewrittenArgument.Syntax,
rewrittenArgument.ConstantValue,
argumentType); //need to have a non-null type here for TempHelpers.StoreToTemp.
}
if (argumentType.Kind == SymbolKind.TypeParameter)
{
// If the argument has a type parameter type, then we'll box it right away
// so that the same object is passed to both Monitor.Enter and Monitor.Exit.
argumentType = this.compilation.GetSpecialType(SpecialType.System_Object);
rewrittenArgument = MakeConversion(
rewrittenArgument.Syntax,
rewrittenArgument,
ConversionKind.Boxing,
argumentType,
@checked: false,
constantValueOpt: rewrittenArgument.ConstantValue);
}
BoundAssignmentOperator assignmentToLockTemp;
BoundLocal boundLockTemp = this.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 <BoundNode>(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 = this.compilation.GetSpecialType(SpecialType.System_Boolean);
BoundAssignmentOperator assignmentToLockTakenTemp;
BoundLocal boundLockTakenTemp = this.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(
MakeInitialLockSequencePoint(boundLockTempInit, lockSyntax),
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 <BoundNode>(boundLockTemp), ErrorTypeSymbol.UnknownResultType);
}
BoundStatement enterCall = new BoundExpressionStatement(
lockSyntax,
enterCallExpr);
return(new BoundBlock(
lockSyntax,
ImmutableArray.Create(boundLockTemp.LocalSymbol),
ImmutableArray.Create(
MakeInitialLockSequencePoint(boundLockTempInit, lockSyntax),
enterCall,
new BoundTryStatement(
lockSyntax,
BoundBlock.SynthesizedNoLocals(lockSyntax, rewrittenBody),
ImmutableArray <BoundCatchBlock> .Empty,
BoundBlock.SynthesizedNoLocals(lockSyntax, exitCall)))));
}
}
public override BoundNode VisitNullCoalescingAssignmentOperator(BoundNullCoalescingAssignmentOperator node)
{
SyntaxNode syntax = node.Syntax;
var temps = ArrayBuilder <LocalSymbol> .GetInstance();
var stores = ArrayBuilder <BoundExpression> .GetInstance();
// Rewrite LHS with temporaries to prevent double-evaluation of side effects, as we'll need to use it multiple times.
BoundExpression transformedLHS = TransformCompoundAssignmentLHS(node.LeftOperand, stores, temps, node.LeftOperand.HasDynamicType());
var lhsRead = MakeRValue(transformedLHS);
BoundExpression loweredRight = VisitExpression(node.RightOperand);
return(node.IsNullableValueTypeAssignment ?
rewriteNullCoalescingAssignmentForValueType() :
rewriteNullCoalscingAssignmentStandard());
BoundExpression rewriteNullCoalscingAssignmentStandard()
{
// Now that LHS is transformed with temporaries, we rewrite this node into a coalesce expression:
// lhsRead ?? (transformedLHS = loweredRight)
// transformedLHS = loweredRight
// isCompoundAssignment is only used for dynamic scenarios, and we want those scenarios to treat this like a standard assignment.
// See CodeGenNullCoalescingAssignmentTests.CoalescingAssignment_DynamicRuntimeCastFailure, which will fail if
// isCompoundAssignment is set to true. It will fail to throw a runtime binder cast exception.
BoundExpression assignment = MakeAssignmentOperator(syntax, transformedLHS, loweredRight, node.LeftOperand.Type, used: true, isChecked: false, isCompoundAssignment: false);
// lhsRead ?? (transformedLHS = loweredRight)
BoundExpression conditionalExpression = MakeNullCoalescingOperator(syntax, lhsRead, assignment, Conversion.Identity, BoundNullCoalescingOperatorResultKind.LeftType, node.LeftOperand.Type);
return((temps.Count == 0 && stores.Count == 0) ?
conditionalExpression :
new BoundSequence(
syntax,
temps.ToImmutableAndFree(),
stores.ToImmutableAndFree(),
conditionalExpression,
conditionalExpression.Type));
}
// Rewrites the null coalescing operator in the case where the result type is the underlying
// non-nullable value type of the left side
BoundExpression rewriteNullCoalescingAssignmentForValueType()
{
Debug.Assert(node.LeftOperand.Type.IsNullableType());
Debug.Assert(node.Type.Equals(node.RightOperand.Type));
// We lower the expression to this form:
//
// var tmp = lhsRead.GetValueOrDefault()
// lhsRead.HasValue ? tmp : { /* sequence */ tmp = loweredRight; transformedLhs = tmp; tmp }
var leftOperand = node.LeftOperand;
if (!TryGetNullableMethod(leftOperand.Syntax,
leftOperand.Type,
SpecialMember.System_Nullable_T_GetValueOrDefault,
out var getValueOrDefault))
{
return(BadExpression(node));
}
if (!TryGetNullableMethod(leftOperand.Syntax,
leftOperand.Type,
SpecialMember.System_Nullable_T_get_HasValue,
out var hasValue))
{
return(BadExpression(node));
}
// If null coalescing assignment is supported in expression trees, the below code
// will need to be updated to support property accesses as well as calls. Currently,
// MakeRValue will never return a BoundPropertyAccess except in expression trees.
Debug.Assert(!_inExpressionLambda && lhsRead.Kind != BoundKind.PropertyAccess);
// If lhsRead is a call, such as to a property accessor, save the result off to a temp. This doesn't affect
// the standard ??= case because it only uses lhsRead once.
if (lhsRead.Kind == BoundKind.Call)
{
var lhsTemp = _factory.StoreToTemp(lhsRead, out var store, kind: SynthesizedLocalKind.Spill);
stores.Add(store);
temps.Add(lhsTemp.LocalSymbol);
lhsRead = lhsTemp;
}
// tmp = lhsRead.GetValueOrDefault();
var tmp = _factory.StoreToTemp(BoundCall.Synthesized(leftOperand.Syntax, lhsRead, getValueOrDefault),
out var getValueOrDefaultStore,
kind: SynthesizedLocalKind.Spill);
stores.Add(getValueOrDefaultStore);
temps.Add(tmp.LocalSymbol);
// tmp = loweredRight;
var tmpAssignment = MakeAssignmentOperator(node.Syntax, tmp, loweredRight, node.Type, used: true, isChecked: false, isCompoundAssignment: false);
// transformedLhs = tmp;
var transformedLhsAssignment =
MakeAssignmentOperator(
node.Syntax,
transformedLHS,
MakeConversionNode(tmp, transformedLHS.Type, @checked: false),
node.LeftOperand.Type,
used: true,
isChecked: false,
isCompoundAssignment: false);
// lhsRead.HasValue
var lhsReadHasValue = BoundCall.Synthesized(leftOperand.Syntax, lhsRead, hasValue);
// { tmp = b; transformedLhs = tmp; tmp }
var alternative = _factory.Sequence(ImmutableArray <LocalSymbol> .Empty, ImmutableArray.Create(tmpAssignment, transformedLhsAssignment), tmp);
// lhsRead.HasValue ? tmp : { /* sequence */ tmp = loweredRight; transformedLhs = tmp; tmp }
var ternary = _factory.Conditional(lhsReadHasValue, tmp, alternative, tmp.Type);
return(_factory.Sequence(temps.ToImmutableAndFree(), stores.ToImmutableAndFree(), ternary));
}
}
private BoundExpression MakeNullCoalescingOperator(
SyntaxNode syntax,
BoundExpression rewrittenLeft,
BoundExpression rewrittenRight,
Conversion leftConversion,
BoundNullCoalescingOperatorResultKind resultKind,
TypeSymbol rewrittenResultType)
{
Debug.Assert(rewrittenLeft != null);
Debug.Assert(rewrittenRight != null);
Debug.Assert(leftConversion.IsValid);
Debug.Assert((object)rewrittenResultType != null);
Debug.Assert(rewrittenRight.Type.Equals(rewrittenResultType, TypeCompareKind.IgnoreDynamicAndTupleNames | TypeCompareKind.IgnoreNullableModifiersForReferenceTypes));
if (_inExpressionLambda)
{
TypeSymbol strippedLeftType = rewrittenLeft.Type.StrippedType();
Conversion rewrittenConversion = TryMakeConversion(syntax, leftConversion, strippedLeftType, rewrittenResultType);
if (!rewrittenConversion.Exists)
{
return(BadExpression(syntax, rewrittenResultType, rewrittenLeft, rewrittenRight));
}
return(new BoundNullCoalescingOperator(syntax, rewrittenLeft, rewrittenRight, rewrittenConversion, resultKind, rewrittenResultType));
}
var isUnconstrainedTypeParameter = rewrittenLeft.Type != null && !rewrittenLeft.Type.IsReferenceType && !rewrittenLeft.Type.IsValueType;
// first we can make a small optimization:
// If left is a constant then we already know whether it is null or not. If it is null then we
// can simply generate "right". If it is not null then we can simply generate
// MakeConversion(left). This does not hold when the left is an unconstrained type parameter: at runtime,
// it can be either left or right depending on the runtime type of T
if (!isUnconstrainedTypeParameter)
{
if (rewrittenLeft.IsDefaultValue())
{
return(rewrittenRight);
}
if (rewrittenLeft.ConstantValue != null)
{
Debug.Assert(!rewrittenLeft.ConstantValue.IsNull);
return(GetConvertedLeftForNullCoalescingOperator(rewrittenLeft, leftConversion, rewrittenResultType));
}
}
// string concatenation is never null.
// interpolated string lowering may introduce redundant null coalescing, which we have to remove.
if (IsStringConcat(rewrittenLeft))
{
return(GetConvertedLeftForNullCoalescingOperator(rewrittenLeft, leftConversion, rewrittenResultType));
}
// if left conversion is intrinsic implicit (always succeeds) and results in a reference type
// we can apply conversion before doing the null check that allows for a more efficient IL emit.
if (rewrittenLeft.Type.IsReferenceType &&
leftConversion.IsImplicit &&
!leftConversion.IsUserDefined)
{
if (!leftConversion.IsIdentity)
{
rewrittenLeft = MakeConversionNode(rewrittenLeft.Syntax, rewrittenLeft, leftConversion, rewrittenResultType, @checked: false);
}
return(new BoundNullCoalescingOperator(syntax, rewrittenLeft, rewrittenRight, Conversion.Identity, resultKind, rewrittenResultType));
}
if (leftConversion.IsIdentity || leftConversion.Kind == ConversionKind.ExplicitNullable)
{
var conditionalAccess = rewrittenLeft as BoundLoweredConditionalAccess;
if (conditionalAccess != null &&
(conditionalAccess.WhenNullOpt == null || NullableNeverHasValue(conditionalAccess.WhenNullOpt)))
{
var notNullAccess = NullableAlwaysHasValue(conditionalAccess.WhenNotNull);
if (notNullAccess != null)
{
var whenNullOpt = rewrittenRight;
if (whenNullOpt.Type.IsNullableType())
{
notNullAccess = conditionalAccess.WhenNotNull;
}
if (whenNullOpt.IsDefaultValue() && whenNullOpt.Type.SpecialType != SpecialType.System_Decimal)
{
whenNullOpt = null;
}
return(conditionalAccess.Update(
conditionalAccess.Receiver,
conditionalAccess.HasValueMethodOpt,
whenNotNull: notNullAccess,
whenNullOpt: whenNullOpt,
id: conditionalAccess.Id,
type: rewrittenResultType
));
}
}
}
// Optimize left ?? right to left.GetValueOrDefault() when left is T? and right is the default value of T
if (rewrittenLeft.Type.IsNullableType() &&
RemoveIdentityConversions(rewrittenRight).IsDefaultValue() &&
rewrittenRight.Type.Equals(rewrittenLeft.Type.GetNullableUnderlyingType(), TypeCompareKind.AllIgnoreOptions) &&
TryGetNullableMethod(rewrittenLeft.Syntax, rewrittenLeft.Type, SpecialMember.System_Nullable_T_GetValueOrDefault, out MethodSymbol getValueOrDefault))
{
return(BoundCall.Synthesized(rewrittenLeft.Syntax, rewrittenLeft, getValueOrDefault));
}
// We lower left ?? right to
//
// var temp = left;
// (temp != null) ? MakeConversion(temp) : right
//
BoundAssignmentOperator tempAssignment;
BoundLocal boundTemp = _factory.StoreToTemp(rewrittenLeft, out tempAssignment);
// temp != null
BoundExpression nullCheck = MakeNullCheck(syntax, boundTemp, BinaryOperatorKind.NotEqual);
// MakeConversion(temp, rewrittenResultType)
BoundExpression convertedLeft = GetConvertedLeftForNullCoalescingOperator(boundTemp, leftConversion, rewrittenResultType);
Debug.Assert(convertedLeft.HasErrors || convertedLeft.Type.Equals(rewrittenResultType, TypeCompareKind.IgnoreDynamicAndTupleNames | TypeCompareKind.IgnoreNullableModifiersForReferenceTypes));
// (temp != null) ? MakeConversion(temp, LeftConversion) : RightOperand
BoundExpression conditionalExpression = RewriteConditionalOperator(
syntax: syntax,
rewrittenCondition: nullCheck,
rewrittenConsequence: convertedLeft,
rewrittenAlternative: rewrittenRight,
constantValueOpt: null,
rewrittenType: rewrittenResultType,
isRef: false);
Debug.Assert(conditionalExpression.ConstantValue == null); // we shouldn't have hit this else case otherwise
Debug.Assert(conditionalExpression.Type.Equals(rewrittenResultType, TypeCompareKind.IgnoreDynamicAndTupleNames | TypeCompareKind.IgnoreNullableModifiersForReferenceTypes));
return(new BoundSequence(
syntax: syntax,
locals: ImmutableArray.Create(boundTemp.LocalSymbol),
sideEffects: ImmutableArray.Create <BoundExpression>(tempAssignment),
value: conditionalExpression,
type: rewrittenResultType));
}
private BoundStatement MakeSwitchStatementWithNullableExpression(
SyntaxNode syntax,
BoundExpression rewrittenExpression,
ImmutableArray <BoundSwitchSection> rewrittenSections,
LabelSymbol constantTargetOpt,
ImmutableArray <LocalSymbol> locals,
ImmutableArray <LocalFunctionSymbol> localFunctions,
GeneratedLabelSymbol breakLabel,
BoundSwitchStatement oldNode)
{
Debug.Assert(rewrittenExpression.Type.IsNullableType());
var exprSyntax = rewrittenExpression.Syntax;
var exprNullableType = rewrittenExpression.Type;
var statementBuilder = ArrayBuilder <BoundStatement> .GetInstance();
// Rewrite the nullable expression to a temp as we might have a user defined conversion from source expression to switch governing type.
// We can avoid generating the temp if the expression is a bound local.
LocalSymbol tempLocal;
if (rewrittenExpression.Kind != BoundKind.Local)
{
BoundAssignmentOperator assignmentToTemp;
BoundLocal boundTemp = _factory.StoreToTemp(rewrittenExpression, out assignmentToTemp);
var tempAssignment = new BoundExpressionStatement(exprSyntax, assignmentToTemp);
statementBuilder.Add(tempAssignment);
tempLocal = boundTemp.LocalSymbol;
rewrittenExpression = boundTemp;
}
else
{
tempLocal = null;
}
// Generate a BoundConditionalGoto with null check as the conditional expression and appropriate switch label as the target: null, default or exit label.
BoundStatement condGotoNullValueTargetLabel = new BoundConditionalGoto(
exprSyntax,
condition: MakeNullCheck(exprSyntax, rewrittenExpression, BinaryOperatorKind.NullableNullEqual),
jumpIfTrue: true,
label: GetNullValueTargetSwitchLabel(rewrittenSections, breakLabel));
// Rewrite the switch statement using nullable expression's underlying value as the switch expression.
// rewrittenExpression.GetValueOrDefault()
MethodSymbol getValueOrDefault = UnsafeGetNullableMethod(syntax, exprNullableType, SpecialMember.System_Nullable_T_GetValueOrDefault);
BoundCall callGetValueOrDefault = BoundCall.Synthesized(exprSyntax, rewrittenExpression, getValueOrDefault);
rewrittenExpression = callGetValueOrDefault;
// rewrite switch statement
BoundStatement rewrittenSwitchStatement = MakeSwitchStatementWithNonNullableExpression(
syntax,
condGotoNullValueTargetLabel,
rewrittenExpression,
rewrittenSections,
constantTargetOpt,
locals,
localFunctions,
breakLabel,
oldNode);
statementBuilder.Add(rewrittenSwitchStatement);
return(new BoundBlock(
syntax,
locals: (object)tempLocal == null ? ImmutableArray <LocalSymbol> .Empty : ImmutableArray.Create <LocalSymbol>(tempLocal),
statements: statementBuilder.ToImmutableAndFree()));
}
/// <summary>
/// Generates a submission initialization part of a Script type constructor that represents an interactive submission.
/// </summary>
/// <remarks>
/// The constructor takes a parameter of type Roslyn.Scripting.Session - the session reference.
/// It adds the object being constructed into the session by calling Microsoft.CSharp.RuntimeHelpers.SessionHelpers.SetSubmission,
/// and retrieves strongly typed references on all previous submission script classes whose members are referenced by this submission.
/// The references are stored to fields of the submission (<paramref name="synthesizedFields"/>).
/// </remarks>
private static ImmutableArray <BoundStatement> MakeSubmissionInitialization(CSharpSyntaxNode syntax, MethodSymbol submissionConstructor, SynthesizedSubmissionFields synthesizedFields, CSharpCompilation compilation)
{
Debug.Assert(submissionConstructor.ParameterCount == 2);
BoundStatement[] result = new BoundStatement[1 + synthesizedFields.Count];
var sessionReference = new BoundParameter(syntax, submissionConstructor.Parameters[0])
{
WasCompilerGenerated = true
};
var submissionGetter = (MethodSymbol)compilation.GetWellKnownTypeMember(
WellKnownMember.Microsoft_CSharp_RuntimeHelpers_SessionHelpers__GetSubmission
);
var submissionAdder = (MethodSymbol)compilation.GetWellKnownTypeMember(
WellKnownMember.Microsoft_CSharp_RuntimeHelpers_SessionHelpers__SetSubmission
);
// TODO: report missing adder/getter
Debug.Assert((object)submissionAdder != null && (object)submissionGetter != null);
var intType = compilation.GetSpecialType(SpecialType.System_Int32);
var thisReference = new BoundThisReference(syntax, submissionConstructor.ContainingType)
{
WasCompilerGenerated = true
};
int i = 0;
// hostObject = (THostObject)SessionHelpers.SetSubmission(<session>, <slot index>, this);
var slotIndex = compilation.GetSubmissionSlotIndex();
Debug.Assert(slotIndex >= 0);
BoundExpression setSubmission = BoundCall.Synthesized(syntax,
null,
submissionAdder,
sessionReference,
new BoundLiteral(syntax, ConstantValue.Create(slotIndex), intType)
{
WasCompilerGenerated = true
},
thisReference
);
var hostObjectField = synthesizedFields.GetHostObjectField();
if ((object)hostObjectField != null)
{
setSubmission = new BoundAssignmentOperator(syntax,
new BoundFieldAccess(syntax, thisReference, hostObjectField, ConstantValue.NotAvailable)
{
WasCompilerGenerated = true
},
BoundConversion.Synthesized(syntax,
setSubmission,
Conversion.ExplicitReference,
false,
true,
ConstantValue.NotAvailable,
hostObjectField.Type
),
hostObjectField.Type
)
{
WasCompilerGenerated = true
};
}
result[i++] = new BoundExpressionStatement(syntax, setSubmission)
{
WasCompilerGenerated = true
};
foreach (var field in synthesizedFields.FieldSymbols)
{
var targetScriptClass = (ImplicitNamedTypeSymbol)field.Type;
var targetSubmissionId = targetScriptClass.DeclaringCompilation.GetSubmissionSlotIndex();
Debug.Assert(targetSubmissionId >= 0);
// this.<field> = (<FieldType>)SessionHelpers.GetSubmission(<session>, <i>);
result[i++] =
new BoundExpressionStatement(syntax,
new BoundAssignmentOperator(syntax,
new BoundFieldAccess(syntax, thisReference, field, ConstantValue.NotAvailable)
{
WasCompilerGenerated = true
},
BoundConversion.Synthesized(syntax,
BoundCall.Synthesized(syntax,
null,
submissionGetter,
sessionReference,
new BoundLiteral(syntax, ConstantValue.Create(targetSubmissionId), intType)
{
WasCompilerGenerated = true
}),
Conversion.ExplicitReference,
false,
true,
ConstantValue.NotAvailable,
targetScriptClass
),
targetScriptClass
)
{
WasCompilerGenerated = true
})
{
WasCompilerGenerated = true
};
}
Debug.Assert(i == result.Length);
return(result.AsImmutableOrNull());
}
/// <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);
/// </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);
MethodSymbol updateMethod = (MethodSymbol)compilation.GetSpecialTypeMember(isAddMethod ? SpecialMember.System_Delegate__Combine : SpecialMember.System_Delegate__Remove);
MethodSymbol compareExchangeMethod = GetConstructedCompareExchangeMethod(delegateType, compilation, accessor.Locations[0], diagnostics);
if ((object)compareExchangeMethod == null)
{
return(new BoundBlock(syntax,
localsOpt: default(ImmutableArray <LocalSymbol>),
statements: ImmutableArray.Create <BoundStatement>(
new BoundReturnStatement(syntax,
expressionOpt: null)
{
WasCompilerGenerated = true
}))
{
WasCompilerGenerated = true
});
}
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, delegateType);
boundTmps[i] = new BoundLocal(syntax, tmps[i], null, delegateType);
}
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
};
// 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)
BoundExpression delegateUpdate = BoundConversion.SynthesizedNonUserDefined(syntax,
operand: BoundCall.Synthesized(syntax,
receiverOpt: null,
method: updateMethod,
arguments: ImmutableArray.Create <BoundExpression>(boundTmps[1], boundParameter)),
kind: ConversionKind.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
};
BoundStatement @return = new BoundReturnStatement(syntax,
expressionOpt: null)
{
WasCompilerGenerated = true
};
return(new BoundBlock(syntax,
localsOpt: tmps.AsImmutableOrNull(),
statements: ImmutableArray.Create <BoundStatement>(
tmp0Init,
loopStart,
tmp1Update,
tmp2Update,
tmp0Update,
loopEnd,
@return))
{
WasCompilerGenerated = true
});
}
/// <summary>
/// Lower a foreach loop that will enumerate a multi-dimensional array.
///
/// A[...] a = x;
/// int q_0 = a.GetUpperBound(0), q_1 = a.GetUpperBound(1), ...;
/// for (int p_0 = a.GetLowerBound(0); p_0 <= q_0; p_0 = p_0 + 1)
/// for (int p_1 = a.GetLowerBound(1); p_1 <= q_1; p_1 = p_1 + 1)
/// ...
/// { V v = (V)a[p_0, p_1, ...]; /* body */ }
/// </summary>
/// <remarks>
/// We will follow Dev10 in diverging from the C# 4 spec by ignoring Array's
/// implementation of IEnumerable and just indexing into its elements.
///
/// NOTE: We're assuming that sequence points have already been generated.
/// Otherwise, lowering to nested for-loops would generated spurious ones.
/// </remarks>
private BoundStatement RewriteMultiDimensionalArrayForEachStatement(BoundForEachStatement node)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)node.Syntax;
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
Debug.Assert(collectionExpression.Type.IsArray());
ArrayTypeSymbol arrayType = (ArrayTypeSymbol)collectionExpression.Type;
int rank = arrayType.Rank;
Debug.Assert(rank > 1);
TypeSymbol intType = compilation.GetSpecialType(SpecialType.System_Int32);
TypeSymbol boolType = compilation.GetSpecialType(SpecialType.System_Boolean);
// Values we'll use every iteration
MethodSymbol getLowerBoundMethod = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_Array__GetLowerBound);
MethodSymbol getUpperBoundMethod = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_Array__GetUpperBound);
BoundExpression rewrittenExpression = (BoundExpression)Visit(collectionExpression);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
// A[...] a
LocalSymbol arrayVar = factory.SynthesizedLocal(arrayType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArray);
BoundLocal boundArrayVar = MakeBoundLocal(forEachSyntax, arrayVar, arrayType);
// A[...] a = /*node.Expression*/;
BoundStatement arrayVarDecl = MakeLocalDeclaration(forEachSyntax, arrayVar, rewrittenExpression);
AddForEachExpressionSequencePoint(forEachSyntax, ref arrayVarDecl);
// NOTE: dev10 initializes all of the upper bound temps before entering the loop (as opposed to
// initializing each one at the corresponding level of nesting). Doing it at the same time as
// the lower bound would make this code a bit simpler, but it would make it harder to compare
// the roslyn and dev10 IL.
// int q_0, q_1, ...
LocalSymbol[] upperVar = new LocalSymbol[rank];
BoundLocal[] boundUpperVar = new BoundLocal[rank];
BoundStatement[] upperVarDecl = new BoundStatement[rank];
for (int dimension = 0; dimension < rank; dimension++)
{
// int q_dimension
upperVar[dimension] = factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayLimit);
boundUpperVar[dimension] = MakeBoundLocal(forEachSyntax, upperVar[dimension], intType);
ImmutableArray <BoundExpression> dimensionArgument = ImmutableArray.Create(
MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Create(dimension, ConstantValueTypeDiscriminator.Int32),
type: intType));
// a.GetUpperBound(dimension)
BoundExpression currentDimensionUpperBound = BoundCall.Synthesized(forEachSyntax, boundArrayVar, getUpperBoundMethod, dimensionArgument);
// int q_dimension = a.GetUpperBound(dimension);
upperVarDecl[dimension] = MakeLocalDeclaration(forEachSyntax, upperVar[dimension], currentDimensionUpperBound);
}
// int p_0, p_1, ...
LocalSymbol[] positionVar = new LocalSymbol[rank];
BoundLocal[] boundPositionVar = new BoundLocal[rank];
for (int dimension = 0; dimension < rank; dimension++)
{
positionVar[dimension] = factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayIndex);
boundPositionVar[dimension] = MakeBoundLocal(forEachSyntax, positionVar[dimension], intType);
}
// V v
LocalSymbol iterationVar = node.IterationVariable;
TypeSymbol iterationVarType = iterationVar.Type;
// (V)a[p_0, p_1, ...]
BoundExpression iterationVarInitValue = MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: new BoundArrayAccess(forEachSyntax,
expression: boundArrayVar,
indices: ImmutableArray.Create((BoundExpression[])boundPositionVar),
type: arrayType.ElementType),
conversion: node.ElementConversion,
rewrittenType: iterationVarType,
@checked: node.Checked);
// V v = (V)a[p_0, p_1, ...];
BoundStatement iterationVarDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarInitValue);
AddForEachIterationVariableSequencePoint(forEachSyntax, ref iterationVarDecl);
// { V v = (V)a[p_0, p_1, ...]; /* node.Body */ }
BoundStatement innermostLoopBody = new BoundBlock(forEachSyntax,
locals: ImmutableArray.Create(iterationVar),
statements: ImmutableArray.Create(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(
MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Create(dimension, ConstantValueTypeDiscriminator.Int32),
type: intType));
// a.GetLowerBound(dimension)
BoundExpression currentDimensionLowerBound = BoundCall.Synthesized(forEachSyntax, boundArrayVar, getLowerBoundMethod, dimensionArgument);
// int p_dimension = a.GetLowerBound(dimension);
BoundStatement positionVarDecl = MakeLocalDeclaration(forEachSyntax, positionVar[dimension], currentDimensionLowerBound);
GeneratedLabelSymbol breakLabel = dimension == 0 // outermost for-loop
? node.BreakLabel // i.e. the one that break statements will jump to
: new GeneratedLabelSymbol("break"); // Should not affect emitted code since unused
// p_dimension <= q_dimension //NB: OrEqual
BoundExpression exitCondition = new BoundBinaryOperator(
syntax: forEachSyntax,
operatorKind: BinaryOperatorKind.IntLessThanOrEqual,
left: boundPositionVar[dimension],
right: boundUpperVar[dimension],
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: boolType);
// p_dimension = p_dimension + 1;
BoundStatement positionIncrement = MakePositionIncrement(forEachSyntax, boundPositionVar[dimension], intType);
BoundStatement body;
GeneratedLabelSymbol continueLabel;
if (forLoop == null)
{
// innermost for-loop
body = innermostLoopBody;
continueLabel = node.ContinueLabel; //i.e. the one continue statements will actually jump to
}
else
{
body = forLoop;
continueLabel = new GeneratedLabelSymbol("continue"); // Should not affect emitted code since unused
}
forLoop = RewriteForStatement(
syntax: forEachSyntax,
outerLocals: ImmutableArray.Create(positionVar[dimension]),
rewrittenInitializer: positionVarDecl,
rewrittenCondition: exitCondition,
conditionSyntaxOpt: null,
conditionSpanOpt: forEachSyntax.InKeyword.Span,
rewrittenIncrement: positionIncrement,
rewrittenBody: body,
breakLabel: breakLabel,
continueLabel: continueLabel,
hasErrors: node.HasErrors);
}
Debug.Assert(forLoop != null);
BoundStatement result = new BoundBlock(
forEachSyntax,
ImmutableArray.Create(arrayVar).Concat(upperVar.AsImmutableOrNull()),
ImmutableArray.Create(arrayVarDecl).Concat(upperVarDecl.AsImmutableOrNull()).Add(forLoop));
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return(result);
}
private BoundExpression LowerLiftedUnaryOperator(
UnaryOperatorKind kind,
CSharpSyntaxNode syntax,
MethodSymbol method,
BoundExpression loweredOperand,
TypeSymbol type)
{
// First, an optimization. If we know that the operand is always null then
// we can simply lower to the alternative.
BoundExpression optimized = OptimizeLiftedUnaryOperator(kind, syntax, method, loweredOperand, type);
if (optimized != null)
{
return(optimized);
}
// We do not know whether the operand is null or non-null, so we generate:
//
// S? temp = operand;
// R? r = temp.HasValue ?
// new R?(OP(temp.GetValueOrDefault())) :
// default(R?);
BoundAssignmentOperator tempAssignment;
BoundLocal boundTemp = _factory.StoreToTemp(loweredOperand, out tempAssignment);
MethodSymbol getValueOrDefault = GetNullableMethod(syntax, boundTemp.Type, SpecialMember.System_Nullable_T_GetValueOrDefault);
// temp.HasValue
BoundExpression condition = MakeNullableHasValue(syntax, boundTemp);
// temp.GetValueOrDefault()
BoundExpression call_GetValueOrDefault = BoundCall.Synthesized(syntax, boundTemp, getValueOrDefault);
// new R?(temp.GetValueOrDefault())
BoundExpression consequence = GetLiftedUnaryOperatorConsequence(kind, syntax, method, type, call_GetValueOrDefault);
// default(R?)
BoundExpression alternative = new BoundDefaultOperator(syntax, null, type);
// temp.HasValue ?
// new R?(OP(temp.GetValueOrDefault())) :
// default(R?);
BoundExpression conditionalExpression = RewriteConditionalOperator(
syntax: syntax,
rewrittenCondition: condition,
rewrittenConsequence: consequence,
rewrittenAlternative: alternative,
constantValueOpt: null,
rewrittenType: type);
// temp = operand;
// temp.HasValue ?
// new R?(OP(temp.GetValueOrDefault())) :
// default(R?);
return(new BoundSequence(
syntax: syntax,
locals: ImmutableArray.Create <LocalSymbol>(boundTemp.LocalSymbol),
sideEffects: ImmutableArray.Create <BoundExpression>(tempAssignment),
value: conditionalExpression,
type: type));
}
/// <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.CurrentType,
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);
}
private BoundExpression MakeUserDefinedIncrementOperator(BoundIncrementOperator node, BoundExpression rewrittenValueToIncrement)
{
Debug.Assert((object)node.MethodOpt != null);
Debug.Assert(node.MethodOpt.ParameterCount == 1);
bool isLifted = node.OperatorKind.IsLifted();
bool @checked = node.OperatorKind.IsChecked();
BoundExpression rewrittenArgument = rewrittenValueToIncrement;
CSharpSyntaxNode syntax = node.Syntax;
TypeSymbol type = node.MethodOpt.ParameterTypes[0];
if (isLifted)
{
type = _compilation.GetSpecialType(SpecialType.System_Nullable_T).Construct(type);
Debug.Assert(node.MethodOpt.ParameterTypes[0] == node.MethodOpt.ReturnType);
}
if (!node.OperandConversion.IsIdentity)
{
rewrittenArgument = MakeConversion(
syntax: syntax,
rewrittenOperand: rewrittenValueToIncrement,
conversion: node.OperandConversion,
rewrittenType: type,
@checked: @checked);
}
if (!isLifted)
{
return(BoundCall.Synthesized(syntax, null, node.MethodOpt, rewrittenArgument));
}
// S? temp = operand;
// S? r = temp.HasValue ?
// new S?(op_Increment(temp.GetValueOrDefault())) :
// default(S?);
// Unlike the other unary operators, we do not attempt to optimize nullable user-defined
// increment or decrement. The operand is a variable (or property), and so we do not know if
// it is always null/never null.
BoundAssignmentOperator tempAssignment;
BoundLocal boundTemp = _factory.StoreToTemp(rewrittenArgument, out tempAssignment);
MethodSymbol getValueOrDefault = GetNullableMethod(syntax, type, SpecialMember.System_Nullable_T_GetValueOrDefault);
MethodSymbol ctor = GetNullableMethod(syntax, type, SpecialMember.System_Nullable_T__ctor);
// temp.HasValue
BoundExpression condition = MakeNullableHasValue(node.Syntax, boundTemp);
// temp.GetValueOrDefault()
BoundExpression call_GetValueOrDefault = BoundCall.Synthesized(syntax, boundTemp, getValueOrDefault);
// op_Increment(temp.GetValueOrDefault())
BoundExpression userDefinedCall = BoundCall.Synthesized(syntax, null, node.MethodOpt, call_GetValueOrDefault);
// new S?(op_Increment(temp.GetValueOrDefault()))
BoundExpression consequence = new BoundObjectCreationExpression(syntax, ctor, userDefinedCall);
// default(S?)
BoundExpression alternative = new BoundDefaultOperator(syntax, null, type);
// temp.HasValue ?
// new S?(op_Increment(temp.GetValueOrDefault())) :
// default(S?);
BoundExpression conditionalExpression = RewriteConditionalOperator(
syntax: syntax,
rewrittenCondition: condition,
rewrittenConsequence: consequence,
rewrittenAlternative: alternative,
constantValueOpt: null,
rewrittenType: type);
// temp = operand;
// temp.HasValue ?
// new S?(op_Increment(temp.GetValueOrDefault())) :
// default(S?);
return(new BoundSequence(
syntax: syntax,
locals: ImmutableArray.Create <LocalSymbol>(boundTemp.LocalSymbol),
sideEffects: ImmutableArray.Create <BoundExpression>(tempAssignment),
value: conditionalExpression,
type: type));
}
/// <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, 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, expressionOpt: null);
return(BoundBlock.SynthesizedNoLocals(syntax, callStatement, returnStatement));
}
}
/// <summary>
/// Returns an expression which converts the given expression into a string (or null).
/// If necessary, this invokes .ToString() on the expression, to avoid boxing value types.
/// </summary>
private BoundExpression ConvertConcatExprToString(SyntaxNode syntax, BoundExpression expr)
{
// If it's a value type, it'll have been boxed by the +(string, object) or +(object, string)
// operator. Undo that.
if (expr.Kind == BoundKind.Conversion)
{
BoundConversion conv = (BoundConversion)expr;
if (conv.ConversionKind == ConversionKind.Boxing)
{
expr = conv.Operand;
}
}
// Is the expression a literal char? If so, we can
// simply make it a literal string instead and avoid any
// allocations for converting the char to a string at run time.
// Similarly if it's a literal null, don't do anything special.
if (expr.Kind == BoundKind.Literal)
{
ConstantValue cv = ((BoundLiteral)expr).ConstantValue;
if (cv != null)
{
if (cv.SpecialType == SpecialType.System_Char)
{
return(_factory.StringLiteral(cv.CharValue.ToString()));
}
else if (cv.IsNull)
{
return(expr);
}
}
}
// If it's a string already, just return it
if (expr.Type.IsStringType())
{
return(expr);
}
// Evaluate toString at the last possible moment, to avoid spurious diagnostics if it's missing.
// All code paths below here use it.
var objectToStringMethod = UnsafeGetSpecialTypeMethod(syntax, SpecialMember.System_Object__ToString);
// If it's a struct which has overridden ToString, find that method. Note that we might fail to
// find it, e.g. if object.ToString is missing
MethodSymbol structToStringMethod = null;
if (expr.Type.IsValueType && !expr.Type.IsTypeParameter())
{
var type = (NamedTypeSymbol)expr.Type;
var typeToStringMembers = type.GetMembers(objectToStringMethod.Name);
foreach (var member in typeToStringMembers)
{
var toStringMethod = (MethodSymbol)member;
if (toStringMethod.GetLeastOverriddenMethod(type) == (object)objectToStringMethod)
{
structToStringMethod = toStringMethod;
break;
}
}
}
// If it's a special value type, it should have its own ToString method (but we might fail to find
// it if object.ToString is missing). Assume that this won't be removed, and emit a direct call rather
// than a constrained virtual call. This keeps in the spirit of #7079, but expands the range of
// types to all special value types.
if (structToStringMethod != null && expr.Type.SpecialType != SpecialType.None)
{
return(BoundCall.Synthesized(expr.Syntax, expr, structToStringMethod));
}
// - It's a reference type (excluding unconstrained generics): no copy
// - It's a constant: no copy
// - The type definitely doesn't have its own ToString method (i.e. we're definitely calling
// object.ToString on a struct type, not type parameter): no copy (yes this is a versioning issue,
// but that doesn't matter)
// - We're calling the type's own ToString method, and it's effectively readonly (the method or the whole
// type is readonly): no copy
// - Otherwise: copy
// This is to minic the old behaviour, where value types would be boxed before ToString was called on them,
// but with optimizations for readonly methods.
bool callWithoutCopy = expr.Type.IsReferenceType ||
expr.ConstantValue != null ||
(structToStringMethod == null && !expr.Type.IsTypeParameter()) ||
structToStringMethod?.IsEffectivelyReadOnly == true;
// No need for a conditional access if it's a value type - we know it's not null.
if (expr.Type.IsValueType)
{
if (!callWithoutCopy)
{
expr = new BoundPassByCopy(expr.Syntax, expr, expr.Type);
}
return(BoundCall.Synthesized(expr.Syntax, expr, objectToStringMethod));
}
if (callWithoutCopy)
{
return(makeConditionalAccess(expr));
}
else
{
// If we do conditional access on a copy, we need a proper BoundLocal rather than a
// BoundPassByCopy (as it's accessed multiple times). If we don't do this, and the
// receiver is an unconstrained generic parameter, BoundLoweredConditionalAccess has
// to generate a lot of code to ensure it only accesses the copy once (which is pointless).
var temp = _factory.StoreToTemp(expr, out var store);
return(_factory.Sequence(
ImmutableArray.Create(temp.LocalSymbol),
ImmutableArray.Create <BoundExpression>(store),
makeConditionalAccess(temp)));
}
BoundExpression makeConditionalAccess(BoundExpression receiver)
{
int currentConditionalAccessID = ++_currentConditionalAccessID;
return(new BoundLoweredConditionalAccess(
syntax,
receiver,
hasValueMethodOpt: null,
whenNotNull: BoundCall.Synthesized(
syntax,
new BoundConditionalReceiver(syntax, currentConditionalAccessID, expr.Type),
objectToStringMethod),
whenNullOpt: null,
id: currentConditionalAccessID,
type: _compilation.GetSpecialType(SpecialType.System_String)));
}
}
