Refactor DllImportGenerator project for easier extensibility

DllImportGenerator/Benchmarks/Benchmarks.csproj

@@ -14,6 +14,7 @@
   <ItemGroup>
     <ProjectReference Include="..\Ancillary.Interop\Ancillary.Interop.csproj" />
     <ProjectReference Include="..\DllImportGenerator\DllImportGenerator.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
+    <ProjectReference Include="..\Microsoft.Interop.SourceGeneration\Microsoft.Interop.SourceGeneration.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
     <ProjectReference Include="..\TestAssets\NativeExports\NativeExports.csproj" />
     <ProjectReference Include="..\TestAssets\SharedTypes\SharedTypes.csproj" />
   </ItemGroup>

DllImportGenerator/Demo/Demo.csproj

@@ -16,6 +16,7 @@
   <ItemGroup>
     <ProjectReference Include="..\Ancillary.Interop\Ancillary.Interop.csproj" />
     <ProjectReference Include="..\DllImportGenerator\DllImportGenerator.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
+    <ProjectReference Include="..\Microsoft.Interop.SourceGeneration\Microsoft.Interop.SourceGeneration.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
     <ProjectReference Include="..\TestAssets\NativeExports\NativeExports.csproj" />
   </ItemGroup>
 

DllImportGenerator/DllImportGenerator.IntegrationTests/DllImportGenerator.IntegrationTests.csproj

@@ -18,6 +18,7 @@
   <ItemGroup>
     <ProjectReference Include="..\Ancillary.Interop\Ancillary.Interop.csproj" />
     <ProjectReference Include="..\DllImportGenerator\DllImportGenerator.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
+    <ProjectReference Include="..\Microsoft.Interop.SourceGeneration\Microsoft.Interop.SourceGeneration.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
     <ProjectReference Include="..\TestAssets\NativeExports\NativeExports.csproj" />
     <ProjectReference Include="..\TestAssets\SharedTypes\SharedTypes.csproj" />
   </ItemGroup>

DllImportGenerator/DllImportGenerator.sln

@@ -25,10 +25,12 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "SharedTypes", "TestAssets\S
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "TestAssets", "TestAssets", "{C7134A89-8852-4FBE-B426-EFE007C4A819}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Benchmarks", "Benchmarks\Benchmarks.csproj", "{0914590B-C47A-4754-A7BE-E4CD843A92E4}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Benchmarks", "Benchmarks\Benchmarks.csproj", "{0914590B-C47A-4754-A7BE-E4CD843A92E4}"
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "DllImportGenerator.Vsix", "DllImportGenerator.Vsix\DllImportGenerator.Vsix.csproj", "{F9215CDD-7B47-4C17-9166-0BE5066CA6BB}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microsoft.Interop.SourceGeneration", "Microsoft.Interop.SourceGeneration\Microsoft.Interop.SourceGeneration.csproj", "{03FAE24C-728D-419C-B6EC-5C7AE8C45705}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -79,6 +81,10 @@ Global
 		{F9215CDD-7B47-4C17-9166-0BE5066CA6BB}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{F9215CDD-7B47-4C17-9166-0BE5066CA6BB}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{F9215CDD-7B47-4C17-9166-0BE5066CA6BB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{03FAE24C-728D-419C-B6EC-5C7AE8C45705}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{03FAE24C-728D-419C-B6EC-5C7AE8C45705}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{03FAE24C-728D-419C-B6EC-5C7AE8C45705}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{03FAE24C-728D-419C-B6EC-5C7AE8C45705}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

DllImportGenerator/DllImportGenerator/DllImportGenerator.cs

@@ -58,7 +58,7 @@ public void Execute(GeneratorExecutionContext context)
                 generatorDiagnostics.ReportTargetFrameworkNotSupported(MinimumSupportedFrameworkVersion);
             }
 
-            var env = new StubEnvironment(context.Compilation, isSupported, targetFrameworkVersion, context.AnalyzerConfigOptions.GlobalOptions);
+            var env = new StubEnvironment(context.Compilation, isSupported, targetFrameworkVersion, new DllImportGeneratorOptions(context.AnalyzerConfigOptions.GlobalOptions));
             var generatedDllImports = new StringBuilder();
             foreach (SyntaxReference synRef in synRec.Methods)
             {

DllImportGenerator/DllImportGenerator/DllImportGenerator.csproj

@@ -34,12 +34,12 @@
   </ItemGroup>
 
   <ItemGroup>
-    <None Remove="bin\Debug\netstandard2.0\\DllImportGenerator.dll" />
+    <None Include="$(OutputPath)\$(AssemblyName).dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />
+    <None Include="Microsoft.Interop.DllImportGenerator.props" Pack="true" PackagePath="build" />
   </ItemGroup>
 
   <ItemGroup>
-    <None Include="$(OutputPath)\$(AssemblyName).dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />
-    <None Include="Microsoft.Interop.DllImportGenerator.props" Pack="true" PackagePath="build" />
+    <ProjectReference Include="..\Microsoft.Interop.SourceGeneration\Microsoft.Interop.SourceGeneration.csproj" />
   </ItemGroup>
 
   <ItemGroup>
@@ -57,4 +57,14 @@
     </EmbeddedResource>
   </ItemGroup>
 
+  <Target Name="IncludeProjectReferenceInPackage" BeforeTargets="_GetPackageFiles">
+    <MSBuild Projects="@(ProjectReference)" Targets="Build">
+      <Output TaskParameter="TargetOutputs" ItemName="ProjectReferenceOutput" />
+    </MSBuild>
+
+    <ItemGroup>
+      <None Include="@(ProjectReferenceOutput)" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />
+    </ItemGroup>
+  </Target>
+
 </Project>

DllImportGenerator/DllImportGenerator/OptionsHelper.cs → DllImportGenerator/DllImportGenerator/DllImportGeneratorOptions.cs

@@ -1,12 +1,15 @@
-using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Diagnostics;
-using System;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.Runtime.InteropServices;
 
 namespace Microsoft.Interop
 {
+    record DllImportGeneratorOptions(bool GenerateForwarders, bool UseMarshalType) : InteropGenerationOptions(UseMarshalType)
+    {
+        public DllImportGeneratorOptions(AnalyzerConfigOptions options)
+            : this(options.GenerateForwarders(), options.UseMarshalType())
+        {
+        }
+    }
+
     public static class OptionsHelper
     {
         public const string UseMarshalTypeOption = "build_property.DllImportGenerator_UseMarshalType";

DllImportGenerator/DllImportGenerator/DllImportStub.cs

@@ -15,7 +15,7 @@ internal record StubEnvironment(
         Compilation Compilation,
         bool SupportedTargetFramework,
         Version TargetFrameworkVersion,
-        AnalyzerConfigOptions Options);
+        DllImportGeneratorOptions Options);
 
     internal class DllImportStub
     {
@@ -181,7 +181,7 @@ public static DllImportStub Create(
             var managedRetTypeInfo = retTypeInfo;
             // Do not manually handle PreserveSig when generating forwarders.
             // We want the runtime to handle everything.
-            if (!dllImportData.PreserveSig && !env.Options.GenerateForwarders())
+            if (!dllImportData.PreserveSig && !env.Options.GenerateForwarders)
             {
                 // Create type info for native HRESULT return
                 retTypeInfo = TypePositionInfo.CreateForType(env.Compilation.GetSpecialType(SpecialType.System_Int32), NoMarshallingInfo.Instance);
@@ -196,7 +196,7 @@ public static DllImportStub Create(
                     // Transform the managed return type info into an out parameter and add it as the last param
                     TypePositionInfo nativeOutInfo = managedRetTypeInfo with
                     {
-                        InstanceIdentifier = StubCodeGenerator.ReturnIdentifier,
+                        InstanceIdentifier = PInvokeStubCodeGenerator.ReturnIdentifier,
                         RefKind = RefKind.Out,
                         RefKindSyntax = SyntaxKind.OutKeyword,
                         ManagedIndex = TypePositionInfo.ReturnIndex,
@@ -207,8 +207,16 @@ public static DllImportStub Create(
             }
 
             // Generate stub code
-            var stubGenerator = new StubCodeGenerator(method, dllImportData, paramsTypeInfo, retTypeInfo, diagnostics, env.Options);
-            var code = stubGenerator.GenerateSyntax();
+            var stubGenerator = new PInvokeStubCodeGenerator(
+                method,
+                paramsTypeInfo,
+                retTypeInfo,
+                diagnostics,
+                dllImportData.SetLastError && !env.Options.GenerateForwarders,
+                new GeneratedDllImportMarshallingGeneratorFactory(env.Options));
+            string stubTargetName = "__PInvoke__";
+            var code = stubGenerator.GeneratePInvokeBody(IdentifierName(stubTargetName));
+            code = code.AddStatements(CreateTargetFunctionAsLocalStatement(stubGenerator, env.Options, dllImportData, stubTargetName, method.Name));
 
             var additionalAttrs = new List<AttributeListSyntax>();
 
@@ -236,5 +244,156 @@ public static DllImportStub Create(
                 AdditionalAttributes = additionalAttrs.ToArray(),
             };
         }
+
+        private static LocalFunctionStatementSyntax CreateTargetFunctionAsLocalStatement(
+            PInvokeStubCodeGenerator stubGenerator,
+            DllImportGeneratorOptions options,
+            GeneratedDllImportData dllImportData,
+            string stubTargetName,
+            string stubMethodName)
+        {
+            var (parameterList, returnType) = stubGenerator.GenerateTargetMethodSignatureData();
+            return 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);
+        }
+
+        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(DllImportStub.DllImportMember.BestFitMapping))
+            {
+                var name = NameEquals(nameof(DllImportAttribute.BestFitMapping));
+                var value = CreateBoolExpressionSyntax(targetDllImportData.BestFitMapping);
+                newAttributeArgs.Add(AttributeArgument(name, null, value));
+            }
+            if (targetDllImportData.IsUserDefined.HasFlag(DllImportStub.DllImportMember.CallingConvention))
+            {
+                var name = NameEquals(nameof(DllImportAttribute.CallingConvention));
+                var value = CreateEnumExpressionSyntax(targetDllImportData.CallingConvention);
+                newAttributeArgs.Add(AttributeArgument(name, null, value));
+            }
+            if (targetDllImportData.IsUserDefined.HasFlag(DllImportStub.DllImportMember.CharSet))
+            {
+                var name = NameEquals(nameof(DllImportAttribute.CharSet));
+                var value = CreateEnumExpressionSyntax(targetDllImportData.CharSet);
+                newAttributeArgs.Add(AttributeArgument(name, null, value));
+            }
+            if (targetDllImportData.IsUserDefined.HasFlag(DllImportStub.DllImportMember.ExactSpelling))
+            {
+                var name = NameEquals(nameof(DllImportAttribute.ExactSpelling));
+                var value = CreateBoolExpressionSyntax(targetDllImportData.ExactSpelling);
+                newAttributeArgs.Add(AttributeArgument(name, null, value));
+            }
+            if (targetDllImportData.IsUserDefined.HasFlag(DllImportStub.DllImportMember.PreserveSig))
+            {
+                var name = NameEquals(nameof(DllImportAttribute.PreserveSig));
+                var value = CreateBoolExpressionSyntax(targetDllImportData.PreserveSig);
+                newAttributeArgs.Add(AttributeArgument(name, null, value));
+            }
+            if (targetDllImportData.IsUserDefined.HasFlag(DllImportStub.DllImportMember.SetLastError))
+            {
+                var name = NameEquals(nameof(DllImportAttribute.SetLastError));
+                var value = CreateBoolExpressionSyntax(targetDllImportData.SetLastError);
+                newAttributeArgs.Add(AttributeArgument(name, null, value));
+            }
+            if (targetDllImportData.IsUserDefined.HasFlag(DllImportStub.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 = DllImportStub.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.
+                               & ~DllImportStub.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.
+                               & ~DllImportStub.DllImportMember.SetLastError;
+            if (forwardAll)
+            {
+                membersToForward = DllImportStub.DllImportMember.All;
+            }
+
+            var targetDllImportData = new GeneratedDllImportData
+            {
+                CharSet = dllImportData.CharSet,
+                BestFitMapping = dllImportData.BestFitMapping,
+                CallingConvention = dllImportData.CallingConvention,
+                EntryPoint = dllImportData.EntryPoint,
+                ModuleName = dllImportData.ModuleName,
+                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(DllImportStub.DllImportMember.EntryPoint))
+            {
+                targetDllImportData.EntryPoint = originalMethodName;
+            }
+
+            return targetDllImportData;
+        }
     }
 }

DllImportGenerator/DllImportGenerator/GeneratedDllImportMarshallingGeneratorFactory.cs

@@ -0,0 +1,30 @@
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Diagnostics;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Microsoft.Interop
+{
+    class GeneratedDllImportMarshallingGeneratorFactory : DefaultMarshallingGeneratorFactory<DllImportGeneratorOptions>
+    {
+        public GeneratedDllImportMarshallingGeneratorFactory(DllImportGeneratorOptions options) : base(options) { }
+
+        protected override IMarshallingGenerator CreateCore(TypePositionInfo info, StubCodeContext context)
+        {
+            if (Options.GenerateForwarders)
+            {
+                return Forwarder;
+            }
+
+            if (info.IsNativeReturnPosition && !info.IsManagedReturnPosition)
+            {
+                // Use marshaller for native HRESULT return / exception throwing
+                System.Diagnostics.Debug.Assert(info.ManagedType.SpecialType == SpecialType.System_Int32);
+                return HResultException;
+            }
+
+            return base.CreateCore(info, context);
+        }
+    }
+}