Add the UseConreteType analyzer #6370
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| // Copyright (c) Microsoft. All Rights Reserved. Licensed under the MIT license. See License.txt in the project root for license information. | ||||||
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||||||
| using System.Collections.Immutable; | ||||||
| using System.Linq; | ||||||
| using Analyzer.Utilities; | ||||||
| using Analyzer.Utilities.Extensions; | ||||||
| using Analyzer.Utilities.Lightup; | ||||||
| using Analyzer.Utilities.PooledObjects; | ||||||
| using Microsoft.CodeAnalysis; | ||||||
| using Microsoft.CodeAnalysis.Diagnostics; | ||||||
| using Microsoft.CodeAnalysis.Operations; | ||||||
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| namespace Microsoft.NetCore.Analyzers.Performance | ||||||
| { | ||||||
| using static MicrosoftNetCoreAnalyzersResources; | ||||||
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| // Ideas for the future | ||||||
| // ==================== | ||||||
| // Detect arrays/collections of interface types which could be replaced with arrays/collections of concrete types | ||||||
| // Suggest to upgrade members of tuples returned from a method | ||||||
| // only suggest a replacement type if it reduces the number of virtual/interface calls | ||||||
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| /// <summary> | ||||||
| /// Identifies locals/fields/parameters/return types which can be switched to a concrete type to eliminate virtual/interface dispatch. | ||||||
| /// </summary> | ||||||
| /// <remarks> | ||||||
| /// First, we collect a bunch of state: | ||||||
| /// | ||||||
| /// * For all locals/fields/parameters/returns within the named type, we create bags representing the types having been assigned to each. | ||||||
| /// This state will be used to know if we can 'upgrade' the element's type. | ||||||
| /// | ||||||
| /// * For all locals/fields/parameters within the named type, we keep track of when they are used as 'this' for a virtual/interface call. | ||||||
| /// This state will be used to filter out diagnostics for those locals/fields/parameters which aren't inducing virtual/interface calls. | ||||||
| /// There's no sense in upgrading those elements if they aren't the source of virtual/interface calls. | ||||||
| /// | ||||||
| /// * We keep track of all methods assigned to delegates so that we don't suggest changing the signature of these methods. | ||||||
| /// | ||||||
| /// Once all this state has been collected, we perform the actual analysis: | ||||||
| /// | ||||||
| /// * Based on the bags of types being assigned to each local/field/parameter, if there is only one type being assigned and this | ||||||
| /// type is more specialized than what the element's type is, then we suggest upgrading the element's type accordingly. | ||||||
| /// | ||||||
| /// * Based on the bags of types being returned by each method, if there is only one type being returned and this type is more specialized | ||||||
| /// than what was there before, then we suggest upgrading the return type accordingly. | ||||||
| /// | ||||||
| /// Several constraints are applied before we suggest modifying a method signature (either one of its parameters or its return type): | ||||||
| /// | ||||||
| /// * The method cannot be implementing any interface. | ||||||
| /// | ||||||
| /// * The method cannot be virtual, abstract, or be an override. | ||||||
| /// | ||||||
| /// * The method must be private. | ||||||
| /// | ||||||
| /// * The method must not have been assigned to a delegate. | ||||||
| /// </remarks> | ||||||
| [DiagnosticAnalyzer(LanguageNames.CSharp, LanguageNames.VisualBasic)] | ||||||
| public sealed partial class UseConcreteTypeAnalyzer : DiagnosticAnalyzer | ||||||
| { | ||||||
| internal const string RuleId = "CA1859"; | ||||||
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| internal static readonly DiagnosticDescriptor UseConcreteTypeForMethodReturn = DiagnosticDescriptorHelper.Create( | ||||||
| RuleId, | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeTitle)), | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeForMethodReturnMessage)), | ||||||
| DiagnosticCategory.Performance, | ||||||
| RuleLevel.IdeSuggestion, | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeDescription)), | ||||||
| isPortedFxCopRule: false, | ||||||
| isDataflowRule: false); | ||||||
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| internal static readonly DiagnosticDescriptor UseConcreteTypeForParameter = DiagnosticDescriptorHelper.Create( | ||||||
| RuleId, | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeTitle)), | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeForParameterMessage)), | ||||||
| DiagnosticCategory.Performance, | ||||||
| RuleLevel.IdeSuggestion, | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeDescription)), | ||||||
| isPortedFxCopRule: false, | ||||||
| isDataflowRule: false); | ||||||
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| internal static readonly DiagnosticDescriptor UseConcreteTypeForLocal = DiagnosticDescriptorHelper.Create( | ||||||
| RuleId, | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeTitle)), | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeForLocalMessage)), | ||||||
| DiagnosticCategory.Performance, | ||||||
| RuleLevel.IdeSuggestion, | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeDescription)), | ||||||
| isPortedFxCopRule: false, | ||||||
| isDataflowRule: false); | ||||||
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| internal static readonly DiagnosticDescriptor UseConcreteTypeForField = DiagnosticDescriptorHelper.Create( | ||||||
| RuleId, | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeTitle)), | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeForFieldMessage)), | ||||||
| DiagnosticCategory.Performance, | ||||||
| RuleLevel.IdeSuggestion, | ||||||
| CreateLocalizableResourceString(nameof(UseConcreteTypeDescription)), | ||||||
| isPortedFxCopRule: false, | ||||||
| isDataflowRule: false); | ||||||
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| public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => ImmutableArray.Create( | ||||||
| UseConcreteTypeForField, | ||||||
| UseConcreteTypeForLocal, | ||||||
| UseConcreteTypeForMethodReturn, | ||||||
| UseConcreteTypeForParameter); | ||||||
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| public override void Initialize(AnalysisContext context) | ||||||
| { | ||||||
| context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None); | ||||||
| context.EnableConcurrentExecution(); | ||||||
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| context.RegisterSymbolStartAction(context => | ||||||
| { | ||||||
| var coll = Collector.GetInstance(context.Compilation); | ||||||
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| context.RegisterOperationAction(context => coll.HandleInvocation((IInvocationOperation)context.Operation), OperationKind.Invocation); | ||||||
| context.RegisterOperationAction(context => coll.HandleSimpleAssignment((ISimpleAssignmentOperation)context.Operation), OperationKind.SimpleAssignment); | ||||||
| context.RegisterOperationAction(context => coll.HandleCoalesceAssignment((ICoalesceAssignmentOperation)context.Operation), OperationKind.CoalesceAssignment); | ||||||
| context.RegisterOperationAction(context => coll.HandleDeconstructionAssignment((IDeconstructionAssignmentOperation)context.Operation), OperationKind.DeconstructionAssignment); | ||||||
| context.RegisterOperationAction(context => coll.HandleFieldInitializer((IFieldInitializerOperation)context.Operation), OperationKind.FieldInitializer); | ||||||
| context.RegisterOperationAction(context => coll.HandleVariableDeclarator((IVariableDeclaratorOperation)context.Operation), OperationKind.VariableDeclarator); | ||||||
| context.RegisterOperationAction(context => coll.HandleDeclarationExpression((IDeclarationExpressionOperation)context.Operation), OperationKind.DeclarationExpression); | ||||||
| context.RegisterOperationAction(context => coll.HandleReturn((IReturnOperation)context.Operation), OperationKind.Return); | ||||||
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| context.RegisterSymbolEndAction(context => | ||||||
| { | ||||||
| Report(context, coll); | ||||||
| Collector.ReturnInstance(coll, context.CancellationToken); | ||||||
| }); | ||||||
| }, SymbolKind.NamedType); | ||||||
| } | ||||||
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| /// <summary> | ||||||
| /// Given all the accumulated analysis state, generate the diagnostics. | ||||||
| /// </summary> | ||||||
| private static void Report(SymbolAnalysisContext context, Collector coll) | ||||||
|
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| { | ||||||
| foreach (var field in coll.VirtualDispatchFields.Keys) | ||||||
| { | ||||||
| if (coll.FieldAssignments.TryGetValue(field, out var assignments)) | ||||||
| { | ||||||
| Report(field, field.Type, assignments, UseConcreteTypeForField); | ||||||
| } | ||||||
| } | ||||||
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| foreach (var local in coll.VirtualDispatchLocals.Keys) | ||||||
| { | ||||||
| if (coll.LocalAssignments.TryGetValue(local, out var assignments)) | ||||||
| { | ||||||
| Report(local, local.Type, assignments, UseConcreteTypeForLocal); | ||||||
| } | ||||||
| } | ||||||
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| foreach (var parameter in coll.VirtualDispatchParameters.Keys) | ||||||
| { | ||||||
| if (coll.ParameterAssignments.TryGetValue(parameter, out var assignments)) | ||||||
| { | ||||||
| if (parameter.ContainingSymbol is IMethodSymbol method) | ||||||
| { | ||||||
| if (CanUpgrade(method)) | ||||||
| { | ||||||
| Report(parameter, parameter.Type, assignments, UseConcreteTypeForParameter); | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| foreach (var pair in coll.MethodReturns) | ||||||
| { | ||||||
| var method = pair.Key; | ||||||
| var returns = pair.Value; | ||||||
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| if (CanUpgrade(method)) | ||||||
| { | ||||||
| Report(method, method.ReturnType, returns, UseConcreteTypeForMethodReturn); | ||||||
| } | ||||||
| } | ||||||
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| void Report(ISymbol sym, ITypeSymbol fromType, PooledConcurrentSet<ITypeSymbol> assignments, DiagnosticDescriptor desc) | ||||||
| { | ||||||
| using var types = PooledHashSet<ITypeSymbol>.GetInstance(assignments, SymbolEqualityComparer.Default); | ||||||
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| var assignedNull = types.Remove(coll.Void!); | ||||||
|
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| if (types.Count == 1) | ||||||
| { | ||||||
| var toType = types.Single(); | ||||||
| if (assignedNull) | ||||||
| { | ||||||
| toType = toType.WithNullableAnnotation(Analyzer.Utilities.Lightup.NullableAnnotation.Annotated); | ||||||
| } | ||||||
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| if (!toType.DerivesFrom(fromType.OriginalDefinition)) | ||||||
| { | ||||||
| return; | ||||||
| } | ||||||
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| if (toType.TypeKind == TypeKind.Class | ||||||
| && !SymbolEqualityComparer.Default.Equals(fromType, toType) | ||||||
| && toType.SpecialType != SpecialType.System_Object | ||||||
| && toType.SpecialType != SpecialType.System_Delegate) | ||||||
| { | ||||||
| var fromTypeName = GetTypeName(fromType); | ||||||
| var toTypeName = GetTypeName(toType); | ||||||
| var diagnostic = sym.CreateDiagnostic(desc, sym.Name, fromTypeName, toTypeName); | ||||||
| context.ReportDiagnostic(diagnostic); | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| bool CanUpgrade(IMethodSymbol methodSym) => !coll.MethodsAssignedToDelegate.ContainsKey(methodSym); | ||||||
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| static string GetTypeName(ITypeSymbol type) => type.ToDisplayString(SymbolDisplayFormat.CSharpErrorMessageFormat); | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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