Merge pull request #6311 from dotnet/nmirror

Merge nmirror to master

9 files changed, 74 insertions, 5 deletions

diff --git a/src/ILCompiler.Compiler/src/Compiler/CompilationModuleGroup.cs b/src/ILCompiler.Compiler/src/Compiler/CompilationModuleGroup.cs
index 92354badb..edc9b076a 100644
--- a/src/ILCompiler.Compiler/src/Compiler/CompilationModuleGroup.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/CompilationModuleGroup.cs
@@ -38,6 +38,10 @@ namespace ILCompiler
         /// </summary>
         public abstract bool ContainsMethodDictionary(MethodDesc method);
         /// <summary>
+        /// If true, "method" is imported from the set of reference assemblies
+        /// </summary>
+        public abstract bool ImportsMethod(MethodDesc method, bool unboxingStub);        
+        /// <summary>
         /// If true, "type" is exported by the set of input assemblies being compiled
         /// </summary>
         public abstract ExportForm GetExportTypeForm(TypeDesc type);
diff --git a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/RuntimeImportMethodNode.cs b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/RuntimeImportMethodNode.cs
index ac7adb740..796ffce38 100644
--- a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/RuntimeImportMethodNode.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/RuntimeImportMethodNode.cs
@@ -10,7 +10,7 @@ namespace ILCompiler.DependencyAnalysis
     /// <summary>
     /// Represents a method that is imported from the runtime library.
     /// </summary>
-    public class RuntimeImportMethodNode : ExternSymbolNode, IMethodNode
+    public class RuntimeImportMethodNode : ExternSymbolNode, IMethodNode, IExportableSymbolNode
     {
         private MethodDesc _method;
 
@@ -28,6 +28,21 @@ namespace ILCompiler.DependencyAnalysis
             }
         }
 
+        public ExportForm GetExportForm(NodeFactory factory)
+        {
+            // Force non-fake exports for RuntimeImportMethods that have '*' as their module. ('*' means the method is 
+            // REALLY a reference to the linked in native code)
+            if (((EcmaMethod)_method).GetRuntimeImportDllName() == "*")
+            {
+                ExportForm exportForm = factory.CompilationModuleGroup.GetExportMethodForm(_method, false);
+                if (exportForm == ExportForm.ByName)
+                    return ExportForm.None; // Method symbols exported by name are naturally handled by the linker
+                return exportForm;
+            }
+
+            return ExportForm.None; 
+        }
+
         public override int ClassCode => -1173492615;
 
         public override int CompareToImpl(ISortableNode other, CompilerComparer comparer)
diff --git a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/UtcNodeFactory.cs b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/UtcNodeFactory.cs
index 5a026e34a..80aec11b0 100644
--- a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/UtcNodeFactory.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/UtcNodeFactory.cs
@@ -237,12 +237,21 @@ namespace ILCompiler
         {
             if (method.HasCustomAttribute("System.Runtime", "RuntimeImportAttribute"))
             {
-                return new RuntimeImportMethodNode(method);
+                RuntimeImportMethodNode runtimeImportMethod = new RuntimeImportMethodNode(method);
+              
+                // If the method is imported from either the current module or the runtime, reference it directly
+                if (CompilationModuleGroup.ContainsMethodBody(method, false))
+                    return runtimeImportMethod;
+                // If the method is imported from the runtime but not a managed assembly, reference it directly
+                else if (!CompilationModuleGroup.ImportsMethod(method, false))
+                    return runtimeImportMethod;
+                
+                // If the method is imported from a managed assembly, reference it via an import cell
             }
-
-            if (CompilationModuleGroup.ContainsMethodBody(method, false))
+            else
             {
-                return NonExternMethodSymbol(method, false);
+                if (CompilationModuleGroup.ContainsMethodBody(method, false))
+                    return NonExternMethodSymbol(method, false);
             }
 
             return _importedNodeProvider.ImportedMethodCodeNode(this, method, false);
diff --git a/src/ILCompiler.Compiler/src/Compiler/MethodExtensions.cs b/src/ILCompiler.Compiler/src/Compiler/MethodExtensions.cs
index 4b72c15d8..fd274af78 100644
--- a/src/ILCompiler.Compiler/src/Compiler/MethodExtensions.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/MethodExtensions.cs
@@ -30,6 +30,26 @@ namespace ILCompiler
             return null;
         }
 
+        public static string GetRuntimeImportDllName(this EcmaMethod This)
+        {
+            var decoded = This.GetDecodedCustomAttribute("System.Runtime", "RuntimeImportAttribute");
+            if (decoded == null)
+                return null;
+
+            var decodedValue = decoded.Value;
+
+            if (decodedValue.FixedArguments.Length == 2)
+                return (string)decodedValue.FixedArguments[0].Value;
+
+            foreach (var argument in decodedValue.NamedArguments)
+            {
+                if (argument.Name == "DllName")
+                    return (string)argument.Value;
+            }
+
+            return null;
+        }
+
         public static string GetRuntimeExportName(this EcmaMethod This)
         {
             var decoded = This.GetDecodedCustomAttribute("System.Runtime", "RuntimeExportAttribute");
diff --git a/src/ILCompiler.Compiler/src/Compiler/MultiFileCompilationModuleGroup.cs b/src/ILCompiler.Compiler/src/Compiler/MultiFileCompilationModuleGroup.cs
index 5afac3563..842ddefad 100644
--- a/src/ILCompiler.Compiler/src/Compiler/MultiFileCompilationModuleGroup.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/MultiFileCompilationModuleGroup.cs
@@ -58,6 +58,11 @@ namespace ILCompiler
             return ContainsMethodBody(method, false);
         }
 
+        public sealed override bool ImportsMethod(MethodDesc method, bool unboxingStub)
+        {
+            return false;
+        }
+        
         public sealed override ExportForm GetExportTypeForm(TypeDesc type)
         {
             return ExportForm.None;
diff --git a/src/ILCompiler.Compiler/src/Compiler/SingleFileCompilationModuleGroup.cs b/src/ILCompiler.Compiler/src/Compiler/SingleFileCompilationModuleGroup.cs
index a305ad026..90a0043be 100644
--- a/src/ILCompiler.Compiler/src/Compiler/SingleFileCompilationModuleGroup.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/SingleFileCompilationModuleGroup.cs
@@ -31,6 +31,11 @@ namespace ILCompiler
             return ContainsMethodBody(method, false);
         }
 
+        public override bool ImportsMethod(MethodDesc method, bool unboxingStub)
+        {
+            return false;
+        }
+
         public override ExportForm GetExportTypeForm(TypeDesc type)
         {
             return ExportForm.None;
diff --git a/src/ILCompiler.Compiler/src/Compiler/SingleMethodCompilationModuleGroup.cs b/src/ILCompiler.Compiler/src/Compiler/SingleMethodCompilationModuleGroup.cs
index 9f734c1e0..9a1435217 100644
--- a/src/ILCompiler.Compiler/src/Compiler/SingleMethodCompilationModuleGroup.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/SingleMethodCompilationModuleGroup.cs
@@ -50,6 +50,11 @@ namespace ILCompiler
             return false;
         }
 
+        public override bool ImportsMethod(MethodDesc method, bool unboxingStub)
+        {
+            return false;
+        }
+
         public override ExportForm GetExportTypeForm(TypeDesc type)
         {
             return ExportForm.None;
diff --git a/src/System.Private.CoreLib/shared/System/IntPtr.cs b/src/System.Private.CoreLib/shared/System/IntPtr.cs
index f79334a96..d23742fa7 100644
--- a/src/System.Private.CoreLib/shared/System/IntPtr.cs
+++ b/src/System.Private.CoreLib/shared/System/IntPtr.cs
@@ -217,6 +217,9 @@ namespace System
         [CLSCompliant(false)]
         [Intrinsic]
         [NonVersionable]
+#if PROJECTN
+        [System.Runtime.CompilerServices.DependencyReductionRootAttribute]
+#endif
         public unsafe void* ToPointer()
         {
             return _value;
diff --git a/src/System.Private.CoreLib/shared/System/UIntPtr.cs b/src/System.Private.CoreLib/shared/System/UIntPtr.cs
index 9534f4f87..c57dd86a7 100644
--- a/src/System.Private.CoreLib/shared/System/UIntPtr.cs
+++ b/src/System.Private.CoreLib/shared/System/UIntPtr.cs
@@ -208,6 +208,9 @@ namespace System
 
         [Intrinsic]
         [NonVersionable]
+#if PROJECTN
+        [System.Runtime.CompilerServices.DependencyReductionRootAttribute]
+#endif
         public unsafe void* ToPointer()
         {
             return _value;