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|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Diagnostics;
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using static Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
namespace Microsoft.Interop
{
[Generator]
public sealed class DllImportGenerator : IIncrementalGenerator
{
private const string GeneratedDllImport = nameof(GeneratedDllImport);
private const string GeneratedDllImportAttribute = nameof(GeneratedDllImportAttribute);
private static readonly Version MinimumSupportedFrameworkVersion = new Version(5, 0);
internal sealed record IncrementalStubGenerationContext(DllImportStubContext StubContext, ImmutableArray<AttributeSyntax> ForwardedAttributes, GeneratedDllImportData DllImportData, ImmutableArray<Diagnostic> Diagnostics)
{
public bool Equals(IncrementalStubGenerationContext? other)
{
return other is not null
&& StubContext.Equals(other.StubContext)
&& DllImportData.Equals(other.DllImportData)
&& ForwardedAttributes.SequenceEqual(other.ForwardedAttributes, (IEqualityComparer<AttributeSyntax>)new SyntaxEquivalentComparer())
&& Diagnostics.SequenceEqual(other.Diagnostics);
}
public override int GetHashCode()
{
throw new UnreachableException();
}
}
public class IncrementalityTracker
{
public enum StepName
{
CalculateStubInformation,
GenerateSingleStub,
NormalizeWhitespace,
ConcatenateStubs,
OutputSourceFile
}
public record ExecutedStepInfo(StepName Step, object Input);
private List<ExecutedStepInfo> executedSteps = new();
public IEnumerable<ExecutedStepInfo> ExecutedSteps => executedSteps;
internal void RecordExecutedStep(ExecutedStepInfo step) => executedSteps.Add(step);
}
/// <summary>
/// This property provides a test-only hook to enable testing the incrementality of the source generator.
/// This will be removed when https://github.com/dotnet/roslyn/issues/54832 is implemented and can be consumed.
/// </summary>
public IncrementalityTracker? IncrementalTracker { get; set; }
public void Initialize(IncrementalGeneratorInitializationContext context)
{
var methodsToGenerate = context.SyntaxProvider
.CreateSyntaxProvider(
static (node, ct) => ShouldVisitNode(node),
static (context, ct) =>
new
{
Syntax = (MethodDeclarationSyntax)context.Node,
Symbol = (IMethodSymbol)context.SemanticModel.GetDeclaredSymbol(context.Node, ct)!
})
.Where(
static modelData => modelData.Symbol.IsStatic && modelData.Symbol.GetAttributes().Any(
static attribute => attribute.AttributeClass?.ToDisplayString() == TypeNames.GeneratedDllImportAttribute)
);
var compilationAndTargetFramework = context.CompilationProvider
.Select(static (compilation, ct) =>
{
bool isSupported = IsSupportedTargetFramework(compilation, out Version targetFrameworkVersion);
return (compilation, isSupported, targetFrameworkVersion);
});
context.RegisterSourceOutput(
compilationAndTargetFramework
.Combine(methodsToGenerate.Collect()),
static (context, data) =>
{
if (!data.Left.isSupported && data.Right.Any())
{
// We don't block source generation when the TFM is unsupported.
// This allows a user to copy generated source and use it as a starting point
// for manual marshalling if desired.
context.ReportDiagnostic(
Diagnostic.Create(
GeneratorDiagnostics.TargetFrameworkNotSupported,
Location.None,
MinimumSupportedFrameworkVersion.ToString(2)));
}
});
var stubOptions = context.AnalyzerConfigOptionsProvider.Select((options, ct) => new DllImportGeneratorOptions(options.GlobalOptions));
var stubEnvironment = compilationAndTargetFramework
.Combine(stubOptions)
.Select(
static (data, ct) =>
new StubEnvironment(
data.Left.compilation,
data.Left.isSupported,
data.Left.targetFrameworkVersion,
data.Left.compilation.SourceModule.GetAttributes().Any(attr => attr.AttributeClass?.ToDisplayString() == TypeNames.System_Runtime_CompilerServices_SkipLocalsInitAttribute),
data.Right)
);
var methodSourceAndDiagnostics = methodsToGenerate
.Combine(stubEnvironment)
.Select(static (data, ct) => new
{
data.Left.Syntax,
data.Left.Symbol,
Environment = data.Right
})
.Select(
(data, ct) =>
{
IncrementalTracker?.RecordExecutedStep(new IncrementalityTracker.ExecutedStepInfo(IncrementalityTracker.StepName.CalculateStubInformation, data));
return (data.Syntax, StubContext: CalculateStubInformation(data.Syntax, data.Symbol, data.Environment, ct));
}
)
.WithComparer(Comparers.CalculatedContextWithSyntax)
.Combine(stubOptions)
.Select(
(data, ct) =>
{
IncrementalTracker?.RecordExecutedStep(new IncrementalityTracker.ExecutedStepInfo(IncrementalityTracker.StepName.GenerateSingleStub, data));
return GenerateSource(data.Left.StubContext, data.Left.Syntax, data.Right);
}
)
.WithComparer(Comparers.GeneratedSyntax)
// Handle NormalizeWhitespace as a separate stage for incremental runs since it is an expensive operation.
.Select(
(data, ct) =>
{
IncrementalTracker?.RecordExecutedStep(new IncrementalityTracker.ExecutedStepInfo(IncrementalityTracker.StepName.NormalizeWhitespace, data));
return (data.Item1.NormalizeWhitespace().ToFullString(), data.Item2);
})
.Collect()
.WithComparer(Comparers.GeneratedSourceSet)
.Select((generatedSources, ct) =>
{
IncrementalTracker?.RecordExecutedStep(new IncrementalityTracker.ExecutedStepInfo(IncrementalityTracker.StepName.ConcatenateStubs, generatedSources));
StringBuilder source = new();
// Mark in source that the file is auto-generated.
source.AppendLine("// <auto-generated/>");
ImmutableArray<Diagnostic>.Builder diagnostics = ImmutableArray.CreateBuilder<Diagnostic>();
foreach (var generated in generatedSources)
{
source.AppendLine(generated.Item1);
diagnostics.AddRange(generated.Item2);
}
return (source: source.ToString(), diagnostics: diagnostics.ToImmutable());
})
.WithComparer(Comparers.GeneratedSource);
context.RegisterSourceOutput(methodSourceAndDiagnostics,
(context, data) =>
{
IncrementalTracker?.RecordExecutedStep(new IncrementalityTracker.ExecutedStepInfo(IncrementalityTracker.StepName.OutputSourceFile, data));
foreach (var diagnostic in data.Item2)
{
context.ReportDiagnostic(diagnostic);
}
context.AddSource("GeneratedDllImports.g.cs", data.Item1);
});
}
private static List<AttributeSyntax> GenerateSyntaxForForwardedAttributes(AttributeData? suppressGCTransitionAttribute, AttributeData? unmanagedCallConvAttribute)
{
const string CallConvsField = "CallConvs";
// Manually rehydrate the forwarded attributes with fully qualified types so we don't have to worry about any using directives.
List<AttributeSyntax> attributes = new();
if (suppressGCTransitionAttribute is not null)
{
attributes.Add(Attribute(ParseName(TypeNames.SuppressGCTransitionAttribute)));
}
if (unmanagedCallConvAttribute is not null)
{
AttributeSyntax unmanagedCallConvSyntax = Attribute(ParseName(TypeNames.UnmanagedCallConvAttribute));
foreach (var arg in unmanagedCallConvAttribute.NamedArguments)
{
if (arg.Key == CallConvsField)
{
InitializerExpressionSyntax callConvs = InitializerExpression(SyntaxKind.ArrayInitializerExpression);
foreach (var callConv in arg.Value.Values)
{
callConvs = callConvs.AddExpressions(
TypeOfExpression(((ITypeSymbol)callConv.Value!).AsTypeSyntax()));
}
ArrayTypeSyntax arrayOfSystemType = ArrayType(ParseTypeName(TypeNames.System_Type), SingletonList(ArrayRankSpecifier()));
unmanagedCallConvSyntax = unmanagedCallConvSyntax.AddArgumentListArguments(
AttributeArgument(
ArrayCreationExpression(arrayOfSystemType)
.WithInitializer(callConvs))
.WithNameEquals(NameEquals(IdentifierName(CallConvsField))));
}
}
attributes.Add(unmanagedCallConvSyntax);
}
return attributes;
}
private static SyntaxTokenList StripTriviaFromModifiers(SyntaxTokenList tokenList)
{
SyntaxToken[] strippedTokens = new SyntaxToken[tokenList.Count];
for (int i = 0; i < tokenList.Count; i++)
{
strippedTokens[i] = tokenList[i].WithoutTrivia();
}
return new SyntaxTokenList(strippedTokens);
}
private static TypeDeclarationSyntax CreateTypeDeclarationWithoutTrivia(TypeDeclarationSyntax typeDeclaration)
{
return TypeDeclaration(
typeDeclaration.Kind(),
typeDeclaration.Identifier)
.WithTypeParameterList(typeDeclaration.TypeParameterList)
.WithModifiers(typeDeclaration.Modifiers);
}
private static MemberDeclarationSyntax PrintGeneratedSource(
MethodDeclarationSyntax userDeclaredMethod,
DllImportStubContext stub,
BlockSyntax stubCode)
{
// Create stub function
var stubMethod = MethodDeclaration(stub.StubReturnType, userDeclaredMethod.Identifier)
.AddAttributeLists(stub.AdditionalAttributes.ToArray())
.WithModifiers(StripTriviaFromModifiers(userDeclaredMethod.Modifiers))
.WithParameterList(ParameterList(SeparatedList(stub.StubParameters)))
.WithBody(stubCode);
// Stub should have at least one containing type
Debug.Assert(stub.StubContainingTypes.Any());
// Add stub function and DllImport declaration to the first (innermost) containing
MemberDeclarationSyntax containingType = CreateTypeDeclarationWithoutTrivia(stub.StubContainingTypes.First())
.AddMembers(stubMethod);
// Add type to the remaining containing types (skipping the first which was handled above)
foreach (var typeDecl in stub.StubContainingTypes.Skip(1))
{
containingType = CreateTypeDeclarationWithoutTrivia(typeDecl)
.WithMembers(SingletonList(containingType));
}
MemberDeclarationSyntax toPrint = containingType;
// Add type to the containing namespace
if (stub.StubTypeNamespace is not null)
{
toPrint = NamespaceDeclaration(IdentifierName(stub.StubTypeNamespace))
.AddMembers(toPrint);
}
return toPrint;
}
private static bool IsSupportedTargetFramework(Compilation compilation, out Version version)
{
IAssemblySymbol systemAssembly = compilation.GetSpecialType(SpecialType.System_Object).ContainingAssembly;
version = systemAssembly.Identity.Version;
return systemAssembly.Identity.Name switch
{
// .NET Framework
"mscorlib" => false,
// .NET Standard
"netstandard" => false,
// .NET Core (when version < 5.0) or .NET
"System.Runtime" or "System.Private.CoreLib" => version >= MinimumSupportedFrameworkVersion,
_ => false,
};
}
private static GeneratedDllImportData ProcessGeneratedDllImportAttribute(AttributeData attrData)
{
// Found the GeneratedDllImport, but it has an error so report the error.
// This is most likely an issue with targeting an incorrect TFM.
if (attrData.AttributeClass?.TypeKind is null or TypeKind.Error)
{
// [TODO] Report GeneratedDllImport has an error - corrupt metadata?
throw new InvalidProgramException();
}
// Default values for these properties are based on the
// documented semanatics of DllImportAttribute:
// - https://docs.microsoft.com/dotnet/api/system.runtime.interopservices.dllimportattribute
DllImportMember userDefinedValues = DllImportMember.None;
bool bestFitMapping = false;
CallingConvention callingConvention = CallingConvention.Winapi;
CharSet charSet = CharSet.Ansi;
string? entryPoint = null;
bool exactSpelling = false; // VB has different and unusual default behavior here.
bool preserveSig = true;
bool setLastError = false;
bool throwOnUnmappableChar = false;
var stubDllImportData = new GeneratedDllImportData(attrData.ConstructorArguments[0].Value!.ToString());
// All other data on attribute is defined as NamedArguments.
foreach (var namedArg in attrData.NamedArguments)
{
switch (namedArg.Key)
{
default:
Debug.Fail($"An unknown member was found on {GeneratedDllImport}");
continue;
case nameof(GeneratedDllImportData.BestFitMapping):
userDefinedValues |= DllImportMember.BestFitMapping;
bestFitMapping = (bool)namedArg.Value.Value!;
break;
case nameof(GeneratedDllImportData.CallingConvention):
userDefinedValues |= DllImportMember.CallingConvention;
callingConvention = (CallingConvention)namedArg.Value.Value!;
break;
case nameof(GeneratedDllImportData.CharSet):
userDefinedValues |= DllImportMember.CharSet;
charSet = (CharSet)namedArg.Value.Value!;
break;
case nameof(GeneratedDllImportData.EntryPoint):
userDefinedValues |= DllImportMember.EntryPoint;
entryPoint = (string)namedArg.Value.Value!;
break;
case nameof(GeneratedDllImportData.ExactSpelling):
userDefinedValues |= DllImportMember.ExactSpelling;
exactSpelling = (bool)namedArg.Value.Value!;
break;
case nameof(GeneratedDllImportData.PreserveSig):
userDefinedValues |= DllImportMember.PreserveSig;
preserveSig = (bool)namedArg.Value.Value!;
break;
case nameof(GeneratedDllImportData.SetLastError):
userDefinedValues |= DllImportMember.SetLastError;
setLastError = (bool)namedArg.Value.Value!;
break;
case nameof(GeneratedDllImportData.ThrowOnUnmappableChar):
userDefinedValues |= DllImportMember.ThrowOnUnmappableChar;
throwOnUnmappableChar = (bool)namedArg.Value.Value!;
break;
}
}
return new GeneratedDllImportData(attrData.ConstructorArguments[0].Value!.ToString())
{
IsUserDefined = userDefinedValues,
BestFitMapping = bestFitMapping,
CallingConvention = callingConvention,
CharSet = charSet,
EntryPoint = entryPoint,
ExactSpelling = exactSpelling,
PreserveSig = preserveSig,
SetLastError = setLastError,
ThrowOnUnmappableChar = throwOnUnmappableChar
};
}
private static IncrementalStubGenerationContext CalculateStubInformation(MethodDeclarationSyntax syntax, IMethodSymbol symbol, StubEnvironment environment, CancellationToken ct)
{
INamedTypeSymbol? lcidConversionAttrType = environment.Compilation.GetTypeByMetadataName(TypeNames.LCIDConversionAttribute);
INamedTypeSymbol? suppressGCTransitionAttrType = environment.Compilation.GetTypeByMetadataName(TypeNames.SuppressGCTransitionAttribute);
INamedTypeSymbol? unmanagedCallConvAttrType = environment.Compilation.GetTypeByMetadataName(TypeNames.UnmanagedCallConvAttribute);
// Get any attributes of interest on the method
AttributeData? generatedDllImportAttr = null;
AttributeData? lcidConversionAttr = null;
AttributeData? suppressGCTransitionAttribute = null;
AttributeData? unmanagedCallConvAttribute = null;
foreach (var attr in symbol.GetAttributes())
{
if (attr.AttributeClass is not null
&& attr.AttributeClass.ToDisplayString() == TypeNames.GeneratedDllImportAttribute)
{
generatedDllImportAttr = attr;
}
else if (lcidConversionAttrType != null && SymbolEqualityComparer.Default.Equals(attr.AttributeClass, lcidConversionAttrType))
{
lcidConversionAttr = attr;
}
else if (suppressGCTransitionAttrType != null && SymbolEqualityComparer.Default.Equals(attr.AttributeClass, suppressGCTransitionAttrType))
{
suppressGCTransitionAttribute = attr;
}
else if (unmanagedCallConvAttrType != null && SymbolEqualityComparer.Default.Equals(attr.AttributeClass, unmanagedCallConvAttrType))
{
unmanagedCallConvAttribute = attr;
}
}
Debug.Assert(generatedDllImportAttr is not null);
var generatorDiagnostics = new GeneratorDiagnostics();
// Process the GeneratedDllImport attribute
GeneratedDllImportData stubDllImportData = ProcessGeneratedDllImportAttribute(generatedDllImportAttr!);
if (stubDllImportData.IsUserDefined.HasFlag(DllImportMember.BestFitMapping))
{
generatorDiagnostics.ReportConfigurationNotSupported(generatedDllImportAttr!, nameof(GeneratedDllImportData.BestFitMapping));
}
if (stubDllImportData.IsUserDefined.HasFlag(DllImportMember.ThrowOnUnmappableChar))
{
generatorDiagnostics.ReportConfigurationNotSupported(generatedDllImportAttr!, nameof(GeneratedDllImportData.ThrowOnUnmappableChar));
}
if (stubDllImportData.IsUserDefined.HasFlag(DllImportMember.CallingConvention))
{
generatorDiagnostics.ReportConfigurationNotSupported(generatedDllImportAttr!, nameof(GeneratedDllImportData.CallingConvention));
}
if (lcidConversionAttr != null)
{
// Using LCIDConversion with GeneratedDllImport is not supported
generatorDiagnostics.ReportConfigurationNotSupported(lcidConversionAttr, nameof(TypeNames.LCIDConversionAttribute));
}
List<AttributeSyntax> additionalAttributes = GenerateSyntaxForForwardedAttributes(suppressGCTransitionAttribute, unmanagedCallConvAttribute);
// Create the stub.
var dllImportStub = DllImportStubContext.Create(symbol, stubDllImportData, environment, generatorDiagnostics, ct);
return new IncrementalStubGenerationContext(dllImportStub, additionalAttributes.ToImmutableArray(), stubDllImportData, generatorDiagnostics.Diagnostics.ToImmutableArray());
}
private (MemberDeclarationSyntax, ImmutableArray<Diagnostic>) GenerateSource(
IncrementalStubGenerationContext dllImportStub,
MethodDeclarationSyntax originalSyntax,
DllImportGeneratorOptions options)
{
var diagnostics = new GeneratorDiagnostics();
// Generate stub code
var stubGenerator = new PInvokeStubCodeGenerator(
dllImportStub.StubContext.ElementTypeInformation,
dllImportStub.DllImportData.SetLastError && !options.GenerateForwarders,
(elementInfo, ex) => diagnostics.ReportMarshallingNotSupported(originalSyntax, elementInfo, ex.NotSupportedDetails),
dllImportStub.StubContext.GeneratorFactory);
ImmutableArray<AttributeSyntax> forwardedAttributes = dllImportStub.ForwardedAttributes;
const string innerPInvokeName = "__PInvoke__";
var code = stubGenerator.GeneratePInvokeBody(innerPInvokeName);
var dllImport = CreateTargetFunctionAsLocalStatement(
stubGenerator,
dllImportStub.StubContext.Options,
dllImportStub.DllImportData,
innerPInvokeName,
originalSyntax.Identifier.Text);
if (!forwardedAttributes.IsEmpty)
{
dllImport = dllImport.AddAttributeLists(AttributeList(SeparatedList(forwardedAttributes)));
}
code = code.AddStatements(dllImport);
return (PrintGeneratedSource(originalSyntax, dllImportStub.StubContext, code), dllImportStub.Diagnostics.AddRange(diagnostics.Diagnostics));
}
private static LocalFunctionStatementSyntax CreateTargetFunctionAsLocalStatement(
PInvokeStubCodeGenerator stubGenerator,
DllImportGeneratorOptions options,
GeneratedDllImportData dllImportData,
string stubTargetName,
string stubMethodName)
{
var (parameterList, returnType, returnTypeAttributes) = stubGenerator.GenerateTargetMethodSignatureData();
var localDllImport = LocalFunctionStatement(returnType, stubTargetName)
.AddModifiers(
Token(SyntaxKind.ExternKeyword),
Token(SyntaxKind.StaticKeyword),
Token(SyntaxKind.UnsafeKeyword))
.WithSemicolonToken(Token(SyntaxKind.SemicolonToken))
.WithAttributeLists(
SingletonList(AttributeList(
SingletonSeparatedList(
CreateDllImportAttributeForTarget(
GetTargetDllImportDataFromStubData(
dllImportData,
stubMethodName,
options.GenerateForwarders))))))
.WithParameterList(parameterList);
if (returnTypeAttributes is not null)
{
localDllImport = localDllImport.AddAttributeLists(returnTypeAttributes.WithTarget(AttributeTargetSpecifier(Token(SyntaxKind.ReturnKeyword))));
}
return localDllImport;
}
private static AttributeSyntax CreateDllImportAttributeForTarget(GeneratedDllImportData targetDllImportData)
{
var newAttributeArgs = new List<AttributeArgumentSyntax>
{
AttributeArgument(LiteralExpression(
SyntaxKind.StringLiteralExpression,
Literal(targetDllImportData.ModuleName))),
AttributeArgument(
NameEquals(nameof(DllImportAttribute.EntryPoint)),
null,
CreateStringExpressionSyntax(targetDllImportData.EntryPoint!))
};
if (targetDllImportData.IsUserDefined.HasFlag(DllImportMember.BestFitMapping))
{
var name = NameEquals(nameof(DllImportAttribute.BestFitMapping));
var value = CreateBoolExpressionSyntax(targetDllImportData.BestFitMapping);
newAttributeArgs.Add(AttributeArgument(name, null, value));
}
if (targetDllImportData.IsUserDefined.HasFlag(DllImportMember.CallingConvention))
{
var name = NameEquals(nameof(DllImportAttribute.CallingConvention));
var value = CreateEnumExpressionSyntax(targetDllImportData.CallingConvention);
newAttributeArgs.Add(AttributeArgument(name, null, value));
}
if (targetDllImportData.IsUserDefined.HasFlag(DllImportMember.CharSet))
{
var name = NameEquals(nameof(DllImportAttribute.CharSet));
var value = CreateEnumExpressionSyntax(targetDllImportData.CharSet);
newAttributeArgs.Add(AttributeArgument(name, null, value));
}
if (targetDllImportData.IsUserDefined.HasFlag(DllImportMember.ExactSpelling))
{
var name = NameEquals(nameof(DllImportAttribute.ExactSpelling));
var value = CreateBoolExpressionSyntax(targetDllImportData.ExactSpelling);
newAttributeArgs.Add(AttributeArgument(name, null, value));
}
if (targetDllImportData.IsUserDefined.HasFlag(DllImportMember.PreserveSig))
{
var name = NameEquals(nameof(DllImportAttribute.PreserveSig));
var value = CreateBoolExpressionSyntax(targetDllImportData.PreserveSig);
newAttributeArgs.Add(AttributeArgument(name, null, value));
}
if (targetDllImportData.IsUserDefined.HasFlag(DllImportMember.SetLastError))
{
var name = NameEquals(nameof(DllImportAttribute.SetLastError));
var value = CreateBoolExpressionSyntax(targetDllImportData.SetLastError);
newAttributeArgs.Add(AttributeArgument(name, null, value));
}
if (targetDllImportData.IsUserDefined.HasFlag(DllImportMember.ThrowOnUnmappableChar))
{
var name = NameEquals(nameof(DllImportAttribute.ThrowOnUnmappableChar));
var value = CreateBoolExpressionSyntax(targetDllImportData.ThrowOnUnmappableChar);
newAttributeArgs.Add(AttributeArgument(name, null, value));
}
// Create new attribute
return Attribute(
ParseName(typeof(DllImportAttribute).FullName),
AttributeArgumentList(SeparatedList(newAttributeArgs)));
static ExpressionSyntax CreateBoolExpressionSyntax(bool trueOrFalse)
{
return LiteralExpression(
trueOrFalse
? SyntaxKind.TrueLiteralExpression
: SyntaxKind.FalseLiteralExpression);
}
static ExpressionSyntax CreateStringExpressionSyntax(string str)
{
return LiteralExpression(
SyntaxKind.StringLiteralExpression,
Literal(str));
}
static ExpressionSyntax CreateEnumExpressionSyntax<T>(T value) where T : Enum
{
return MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
IdentifierName(typeof(T).FullName),
IdentifierName(value.ToString()));
}
}
private static GeneratedDllImportData GetTargetDllImportDataFromStubData(GeneratedDllImportData dllImportData, string originalMethodName, bool forwardAll)
{
DllImportMember membersToForward = DllImportMember.All
// https://docs.microsoft.com/dotnet/api/system.runtime.interopservices.dllimportattribute.preservesig
// If PreserveSig=false (default is true), the P/Invoke stub checks/converts a returned HRESULT to an exception.
& ~DllImportMember.PreserveSig
// https://docs.microsoft.com/dotnet/api/system.runtime.interopservices.dllimportattribute.setlasterror
// If SetLastError=true (default is false), the P/Invoke stub gets/caches the last error after invoking the native function.
& ~DllImportMember.SetLastError;
if (forwardAll)
{
membersToForward = DllImportMember.All;
}
var targetDllImportData = new GeneratedDllImportData(dllImportData.ModuleName)
{
CharSet = dllImportData.CharSet,
BestFitMapping = dllImportData.BestFitMapping,
CallingConvention = dllImportData.CallingConvention,
EntryPoint = dllImportData.EntryPoint,
ExactSpelling = dllImportData.ExactSpelling,
SetLastError = dllImportData.SetLastError,
PreserveSig = dllImportData.PreserveSig,
ThrowOnUnmappableChar = dllImportData.ThrowOnUnmappableChar,
IsUserDefined = dllImportData.IsUserDefined & membersToForward
};
// If the EntryPoint property is not set, we will compute and
// add it based on existing semantics (i.e. method name).
//
// N.B. The export discovery logic is identical regardless of where
// the name is defined (i.e. method name vs EntryPoint property).
if (!targetDllImportData.IsUserDefined.HasFlag(DllImportMember.EntryPoint))
{
targetDllImportData = targetDllImportData with { EntryPoint = originalMethodName };
}
return targetDllImportData;
}
private static bool ShouldVisitNode(SyntaxNode syntaxNode)
{
// We only support C# method declarations.
if (syntaxNode.Language != LanguageNames.CSharp
|| !syntaxNode.IsKind(SyntaxKind.MethodDeclaration))
{
return false;
}
var methodSyntax = (MethodDeclarationSyntax)syntaxNode;
// Verify the method has no generic types or defined implementation
// and is marked static and partial.
if (methodSyntax.TypeParameterList is not null
|| methodSyntax.Body is not null
|| !methodSyntax.Modifiers.Any(SyntaxKind.StaticKeyword)
|| !methodSyntax.Modifiers.Any(SyntaxKind.PartialKeyword))
{
return false;
}
// Verify that the types the method is declared in are marked partial.
for (SyntaxNode? parentNode = methodSyntax.Parent; parentNode is TypeDeclarationSyntax typeDecl; parentNode = parentNode.Parent)
{
if (!typeDecl.Modifiers.Any(SyntaxKind.PartialKeyword))
{
return false;
}
}
// Filter out methods with no attributes early.
if (methodSyntax.AttributeLists.Count == 0)
{
return false;
}
return true;
}
}
}
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