Extend metadata schema to support function pointers (#1928)

Also:
* update `MetadataTransform` to emit the new metadata
* a simple unit test

7 files changed, 99 insertions, 1 deletions

diff --git a/src/ILCompiler.MetadataTransform/MetadataTransform.sln b/src/ILCompiler.MetadataTransform/MetadataTransform.sln
index 3294ea789..760eba095 100644
--- a/src/ILCompiler.MetadataTransform/MetadataTransform.sln
+++ b/src/ILCompiler.MetadataTransform/MetadataTransform.sln
@@ -11,6 +11,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ILCompiler.TypeSystem", "..
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ILCompiler.MetadataTransform.Tests", "tests\ILCompiler.MetadataTransform.Tests.csproj", "{B4B713D9-68A1-4EB3-8164-4DC8BE69BCBC}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ILMetadataAssembly", "tests\ILMetadataAssembly\ILMetadataAssembly.ilproj", "{347E2A5A-54E5-4482-9723-ED460DE79CE8}"
+EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "PrimaryMetadataAssembly", "tests\PrimaryMetadataAssembly\PrimaryMetadataAssembly.csproj", "{C29B7395-F925-4B0E-972D-187D2D4BFEC7}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SampleMetadataAssembly", "tests\SampleMetadataAssembly\SampleMetadataAssembly.csproj", "{D29B7395-A925-5B0E-972D-387D2D4BFEC8}"
@@ -41,6 +43,10 @@ Global
 		{B4B713D9-68A1-4EB3-8164-4DC8BE69BCBC}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{B4B713D9-68A1-4EB3-8164-4DC8BE69BCBC}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{B4B713D9-68A1-4EB3-8164-4DC8BE69BCBC}.Release|Any CPU.Build.0 = Release|Any CPU
+		{347E2A5A-54E5-4482-9723-ED460DE79CE8}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{347E2A5A-54E5-4482-9723-ED460DE79CE8}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{347E2A5A-54E5-4482-9723-ED460DE79CE8}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{347E2A5A-54E5-4482-9723-ED460DE79CE8}.Release|Any CPU.Build.0 = Release|Any CPU
 		{C29B7395-F925-4B0E-972D-187D2D4BFEC7}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{C29B7395-F925-4B0E-972D-187D2D4BFEC7}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{C29B7395-F925-4B0E-972D-187D2D4BFEC7}.Release|Any CPU.ActiveCfg = Release|Any CPU
diff --git a/src/ILCompiler.MetadataTransform/src/ILCompiler/Metadata/Transform.Type.cs b/src/ILCompiler.MetadataTransform/src/ILCompiler/Metadata/Transform.Type.cs
index 4178a4d60..326cda3b0 100644
--- a/src/ILCompiler.MetadataTransform/src/ILCompiler/Metadata/Transform.Type.cs
+++ b/src/ILCompiler.MetadataTransform/src/ILCompiler/Metadata/Transform.Type.cs
@@ -25,6 +25,7 @@ namespace ILCompiler.Metadata
         private Action<Cts.ArrayType, TypeSpecification> _initArray;
         private Action<Cts.ByRefType, TypeSpecification> _initByRef;
         private Action<Cts.PointerType, TypeSpecification> _initPointer;
+        private Action<Cts.FunctionPointerType, TypeSpecification> _initFunctionPointer;
         private Action<Cts.TypeDesc, TypeSpecification> _initTypeInst;
         private Action<Cts.SignatureTypeVariable, TypeSpecification> _initTypeVar;
         private Action<Cts.SignatureMethodVariable, TypeSpecification> _initMethodVar;
@@ -54,7 +55,8 @@ namespace ILCompiler.Metadata
                     rec = _types.Create((Cts.PointerType)type, _initPointer ?? (_initPointer = InitializePointer));
                     break;
                 case Cts.TypeFlags.FunctionPointer:
-                    throw new NotImplementedException();
+                    rec = _types.Create((Cts.FunctionPointerType)type, _initFunctionPointer ?? (_initFunctionPointer = InitializeFunctionPointer));
+                    break;
                 case Cts.TypeFlags.SignatureTypeVariable:
                     rec = _types.Create((Cts.SignatureTypeVariable)type, _initTypeVar ?? (_initTypeVar = InitializeTypeVariable));
                     break;
@@ -128,6 +130,14 @@ namespace ILCompiler.Metadata
             };
         }
 
+        private void InitializeFunctionPointer(Cts.FunctionPointerType entity, TypeSpecification record)
+        {
+            record.Signature = new FunctionPointerSignature
+            {
+                Signature = HandleMethodSignature(entity.Signature)
+            };
+        }
+
         private void InitializeTypeVariable(Cts.SignatureTypeVariable entity, TypeSpecification record)
         {
             record.Signature = new TypeVariableSignature
diff --git a/src/ILCompiler.MetadataTransform/tests/ILCompiler.MetadataTransform.Tests.csproj b/src/ILCompiler.MetadataTransform/tests/ILCompiler.MetadataTransform.Tests.csproj
index c7212126e..ef9e29a0e 100644
--- a/src/ILCompiler.MetadataTransform/tests/ILCompiler.MetadataTransform.Tests.csproj
+++ b/src/ILCompiler.MetadataTransform/tests/ILCompiler.MetadataTransform.Tests.csproj
@@ -35,6 +35,12 @@
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
       <Targets>Build;DebugSymbolsProjectOutputGroup</Targets>
     </ProjectReference>
+    <ProjectReference Include="ILMetadataAssembly\ILMetadataAssembly.ilproj">
+      <ReferenceOutputAssembly>false</ReferenceOutputAssembly>
+      <OutputItemType>Content</OutputItemType>
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+      <Targets>Build</Targets>
+    </ProjectReference>
     <ProjectReference Include="SampleMetadataAssembly\SampleMetadataAssembly.csproj">
       <ReferenceOutputAssembly>false</ReferenceOutputAssembly>
       <OutputItemType>Content</OutputItemType>
diff --git a/src/ILCompiler.MetadataTransform/tests/ILMetadataAssembly/ILMetadataAssembly.ilproj b/src/ILCompiler.MetadataTransform/tests/ILMetadataAssembly/ILMetadataAssembly.ilproj
new file mode 100644
index 000000000..f1001ee6a
--- /dev/null
+++ b/src/ILCompiler.MetadataTransform/tests/ILMetadataAssembly/ILMetadataAssembly.ilproj
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
+
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <OutputType>Library</OutputType>
+    <AssemblyName>ILMetadataAssembly</AssemblyName>
+    <ProjectGuid>{347E2A5A-54E5-4482-9723-ED460DE79CE8}</ProjectGuid>
+  </PropertyGroup>
+
+  <!-- Default configurations to help VS understand the configurations -->
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+  </PropertyGroup>
+
+  <ItemGroup>
+    <!-- Main has to be the first file. Do not put anything before Main.il -->
+    <Compile Include="Main.il" />
+
+    <Compile Include="TypeWithFunctionPointers.il" />
+  </ItemGroup>
+
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
+</Project>
diff --git a/src/ILCompiler.MetadataTransform/tests/ILMetadataAssembly/Main.il b/src/ILCompiler.MetadataTransform/tests/ILMetadataAssembly/Main.il
new file mode 100644
index 000000000..fda344290
--- /dev/null
+++ b/src/ILCompiler.MetadataTransform/tests/ILMetadataAssembly/Main.il
@@ -0,0 +1,15 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+.assembly extern PrimaryMetadataAssembly
+{
+}
+
+.assembly ILMetadataAssembly
+{
+}
+
+// Mark this as core library so that ILASM doesn't take the code paths that
+// 'fix' all the references to e.g. System.Object to be mscorlib.
+.mscorlib
diff --git a/src/ILCompiler.MetadataTransform/tests/ILMetadataAssembly/TypeWithFunctionPointers.il b/src/ILCompiler.MetadataTransform/tests/ILMetadataAssembly/TypeWithFunctionPointers.il
new file mode 100644
index 000000000..16acdddcf
--- /dev/null
+++ b/src/ILCompiler.MetadataTransform/tests/ILMetadataAssembly/TypeWithFunctionPointers.il
@@ -0,0 +1,9 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+.class public auto ansi beforefieldinit SampleMetadata.TypeWithFunctionPointers
+       extends [PrimaryMetadataAssembly]System.Object
+{
+  .field private static method object *(object) TheField;
+}
diff --git a/src/ILCompiler.MetadataTransform/tests/SimpleTests.cs b/src/ILCompiler.MetadataTransform/tests/SimpleTests.cs
index 900488123..b1d6d06a6 100644
--- a/src/ILCompiler.MetadataTransform/tests/SimpleTests.cs
+++ b/src/ILCompiler.MetadataTransform/tests/SimpleTests.cs
@@ -254,5 +254,30 @@ namespace MetadataTransformTests
             Assert.Equal(iCloneableGenericImplementationMethod, methodImplGenericMethodBody.Method);
             Assert.Equal(implementsICloneableType, methodImplGenericMethodBody.EnclosingType);
         }
+
+        [Fact]
+        public void TestFunctionPointerSignatures()
+        {
+            var ilModule = _context.GetModuleForSimpleName("ILMetadataAssembly");
+            Cts.MetadataType typeWithFunctionPointers = ilModule.GetType("SampleMetadata", "TypeWithFunctionPointers");
+
+            var policy = new SingleFileMetadataPolicy();
+            var transformResult = MetadataTransform.Run(policy,
+                new[] { _systemModule, ilModule });
+
+            var typeWithFunctionPointersType = transformResult.GetTransformedTypeDefinition(typeWithFunctionPointers);
+            var objectType = transformResult.GetTransformedTypeDefinition((Cts.MetadataType)_context.GetWellKnownType(Cts.WellKnownType.Object));
+
+            Assert.Equal(1, typeWithFunctionPointersType.Fields.Count);
+
+            var theField = typeWithFunctionPointersType.Fields[0];
+            Assert.IsType<TypeSpecification>(theField.Signature.Type);
+            var theFieldSignature = (TypeSpecification)theField.Signature.Type;
+            Assert.IsType<FunctionPointerSignature>(theFieldSignature.Signature);
+            var theFieldPointerSignature = (FunctionPointerSignature)theFieldSignature.Signature;
+            Assert.Equal(objectType, theFieldPointerSignature.Signature.ReturnType);
+            Assert.Equal(1, theFieldPointerSignature.Signature.Parameters.Count);
+            Assert.Equal(objectType, theFieldPointerSignature.Signature.Parameters[0]);
+        }
     }
 }
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