Make generic composition details relative addresses

I'm looking at size regressions between .NET Native 1.7 and the current mainline branch. A thing that stood out is universally bigger EETypes. A contributor to this was getting rid of GenericInstanceDescs between 1.7 and 2.0 and replacing them by direct references to generic composition details from the EEType. Size-wise, this was mostly a wash, but we can actually do better - these new fields are not critical to be pointer-sized.
This change turns them into relative pointers. This saves 33 kB on a hello world app. I expect around 100 kB savings on the UWP People app based on my back-of-the-envelope calculation.

Project N baggage:
1. Update pntestcl build configuration to compile it with a C# compiler that is not 8 years old
2. Disable metadata validation transform on class libraries. This is hitting what appears to be a CCI metadata validator bug (Validator.cs:796) where it thinks a modified type should have the same interned key as the unmodified version of it. The act of resolving a modified type strips off the modifier. This ticks off the validator.
3. Fix a Reducer bug where it wasn't marking non-interface constraints as necessary. The C# unmanaged constraint is expressed as [modreq UnmanagedType] ValueType. We were not marking UnmanagedType as necessary.
4. Update checked in binder because this is a file format change

[tfs-changeset: 1708263]

7 files changed, 50 insertions, 20 deletions

diff --git a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/EETypeNode.cs b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/EETypeNode.cs
index 9d07fac1f..1d2c7832d 100644
--- a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/EETypeNode.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/EETypeNode.cs
@@ -846,7 +846,11 @@ namespace ILCompiler.DependencyAnalysis
         {
             if (_type.HasInstantiation && !_type.IsTypeDefinition)
             {
-                objData.EmitPointerRelocOrIndirectionReference(factory.NecessaryTypeSymbol(_type.GetTypeDefinition()));
+                IEETypeNode typeDefNode = factory.NecessaryTypeSymbol(_type.GetTypeDefinition());
+                if (factory.Target.SupportsRelativePointers)
+                    objData.EmitRelativeRelocOrIndirectionReference(typeDefNode);
+                else
+                    objData.EmitPointerRelocOrIndirectionReference(typeDefNode);
 
                 GenericCompositionDetails details;
                 if (_type.GetTypeDefinition() == factory.ArrayOfTEnumeratorType)
@@ -864,7 +868,11 @@ namespace ILCompiler.DependencyAnalysis
                 else
                     details = new GenericCompositionDetails(_type);
 
-                objData.EmitPointerReloc(factory.GenericComposition(details));
+                ISymbolNode compositionNode = factory.GenericComposition(details);
+                if (factory.Target.SupportsRelativePointers)
+                    objData.EmitReloc(compositionNode, RelocType.IMAGE_REL_BASED_RELPTR32);
+                else
+                    objData.EmitPointerReloc(compositionNode);
             }
         }
 
diff --git a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/GCStaticEETypeNode.cs b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/GCStaticEETypeNode.cs
index 1f2d1f3f0..570974205 100644
--- a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/GCStaticEETypeNode.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/GCStaticEETypeNode.cs
@@ -69,7 +69,7 @@ namespace ILCompiler.DependencyAnalysis
             dataBuilder.AddSymbol(this);
 
             // +1 for SyncBlock (in CoreRT static size already includes EEType)
-            Debug.Assert(factory.Target.Abi == TargetAbi.CoreRT);
+            Debug.Assert(factory.Target.Abi == TargetAbi.CoreRT || factory.Target.Abi == TargetAbi.CppCodegen);
             int totalSize = (_gcMap.Size + 1) * _target.PointerSize;
 
             // We only need to check for containsPointers because ThreadStatics are always allocated
diff --git a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/GCStaticsNode.cs b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/GCStaticsNode.cs
index 247d1e9a1..39d886e5e 100644
--- a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/GCStaticsNode.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/GCStaticsNode.cs
@@ -65,7 +65,7 @@ namespace ILCompiler.DependencyAnalysis
             }
 
             dependencyList.Add(factory.GCStaticsRegion, "GCStatics Region");
-            if (factory.Target.Abi == TargetAbi.CoreRT)
+            if (factory.Target.Abi != TargetAbi.ProjectN)
             {
                 dependencyList.Add(GetGCStaticEETypeNode(factory), "GCStatic EEType");
                 if (_preInitFieldInfos != null)
diff --git a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/IndirectionExtensions.cs b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/IndirectionExtensions.cs
new file mode 100644
index 000000000..9265f94f8
--- /dev/null
+++ b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/IndirectionExtensions.cs
@@ -0,0 +1,36 @@
+// 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.
+
+using Internal.Runtime;
+using Internal.TypeSystem;
+
+using Debug = System.Diagnostics.Debug;
+
+namespace ILCompiler.DependencyAnalysis
+{
+    static class IndirectionExtensions
+    {
+        /// <summary>
+        /// Use this api to generate a reloc to a symbol that may be an indirection cell or not as a pointer
+        /// </summary>
+        /// <param name="symbol">symbol to reference</param>
+        /// <param name="indirectionBit">value to OR in to the reloc to represent to runtime code that this pointer is an indirection. Defaults to IndirectionConstants.IndirectionCellPointer</param>
+        /// <param name="delta">Delta from symbol start for value</param>
+        public static void EmitPointerRelocOrIndirectionReference(ref this ObjectDataBuilder builder, ISymbolNode symbol, int delta = 0, int indirectionBit = IndirectionConstants.IndirectionCellPointer)
+        {
+            if (symbol.RepresentsIndirectionCell)
+                delta |= indirectionBit;
+
+            builder.EmitReloc(symbol, (builder.TargetPointerSize == 8) ? RelocType.IMAGE_REL_BASED_DIR64 : RelocType.IMAGE_REL_BASED_HIGHLOW, delta);
+        }
+
+        public static void EmitRelativeRelocOrIndirectionReference(ref this ObjectDataBuilder builder, ISymbolNode symbol, int delta = 0, int indirectionBit = IndirectionConstants.IndirectionCellPointer)
+        {
+            if (symbol.RepresentsIndirectionCell)
+                delta = delta | indirectionBit;
+
+            builder.EmitReloc(symbol, RelocType.IMAGE_REL_BASED_RELPTR32, delta);
+        }
+    }
+}
diff --git a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ObjectDataBuilder.cs b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ObjectDataBuilder.cs
index b42c3e382..29fc23f98 100644
--- a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ObjectDataBuilder.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ObjectDataBuilder.cs
@@ -5,7 +5,6 @@
 using System;
 using System.Collections.Generic;
 using Internal.TypeSystem;
-using Internal.Runtime;
 
 using Debug = System.Diagnostics.Debug;
 
@@ -293,20 +292,6 @@ namespace ILCompiler.DependencyAnalysis
             EmitReloc(symbol, (_target.PointerSize == 8) ? RelocType.IMAGE_REL_BASED_DIR64 : RelocType.IMAGE_REL_BASED_HIGHLOW, delta);
         }
 
-        /// <summary>
-        /// Use this api to generate a reloc to a symbol that may be an indirection cell or not as a pointer
-        /// </summary>
-        /// <param name="symbol">symbol to reference</param>
-        /// <param name="indirectionBit">value to OR in to the reloc to represent to runtime code that this pointer is an indirection. Defaults to IndirectionConstants.IndirectionCellPointer</param>
-        /// <param name="delta">Delta from symbol start for value</param>
-        public void EmitPointerRelocOrIndirectionReference(ISymbolNode symbol, int indirectionBit = IndirectionConstants.IndirectionCellPointer, int delta = 0)
-        {
-            if (symbol.RepresentsIndirectionCell)
-                delta |= indirectionBit;
-
-            EmitReloc(symbol, (_target.PointerSize == 8) ? RelocType.IMAGE_REL_BASED_DIR64 : RelocType.IMAGE_REL_BASED_HIGHLOW, delta);
-        }
-
         public ObjectNode.ObjectData ToObjectData()
         {
 #if DEBUG
diff --git a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ThreadStaticsNode.cs b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ThreadStaticsNode.cs
index 89a479939..80c497e2c 100644
--- a/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ThreadStaticsNode.cs
+++ b/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/ThreadStaticsNode.cs
@@ -20,7 +20,7 @@ namespace ILCompiler.DependencyAnalysis
 
         public ThreadStaticsNode(MetadataType type, NodeFactory factory)
         {
-            Debug.Assert(factory.Target.Abi == TargetAbi.CoreRT);
+            Debug.Assert(factory.Target.Abi == TargetAbi.CoreRT || factory.Target.Abi == TargetAbi.CppCodegen);
             _type = type;
         }
 
diff --git a/src/ILCompiler.Compiler/src/ILCompiler.Compiler.csproj b/src/ILCompiler.Compiler/src/ILCompiler.Compiler.csproj
index 6b8cd40df..05f3c956f 100644
--- a/src/ILCompiler.Compiler/src/ILCompiler.Compiler.csproj
+++ b/src/ILCompiler.Compiler/src/ILCompiler.Compiler.csproj
@@ -102,6 +102,7 @@
     <Compile Include="Compiler\DependencyAnalysis\DefaultConstructorMapNode.cs" />
     <Compile Include="Compiler\DependencyAnalysis\ExternSymbolsImportedNodeProvider.cs" />
     <Compile Include="Compiler\DependencyAnalysis\ExternSymbolsWithIndirectionImportedNodeProvider.cs" />
+    <Compile Include="Compiler\DependencyAnalysis\IndirectionExtensions.cs" />
     <Compile Include="Compiler\DependencyAnalysis\MrtImportImportedNodeProvider.cs" />
     <Compile Include="Compiler\DependencyAnalysis\MrtImports.cs" />
     <Compile Include="Compiler\DependencyAnalysis\MrtProcessedExportAddressTableNode.cs" />