Initial support for preinitialized array in CoreRT (#3558)

* Add PreInitFieldInfo that extracts preinitialized data information from fields that have [PreInitialized] and [InitDataBlob] pointing to RVA field
* Added FrozenArrayNode for frozen arrays with data extracted from preinit RVA data field
* Added GCStaticsPreInitDataNode (CoreRT only) to hold GC pointers for GC static fields. Pre-init data fields points to frozen data, while other data initialized to null. 
* Changed GCStaticsNode to emit a pointer reloc to GCStaticspreInitDataNode and mask 0x2 for the GC static EEType. 
* Changed InitializedStatics in StartupCodeHelper to check for 0x2 and memcpy the GC field data as needed
* Fixed a bug in bad GCStaticsEETypeNode size calculation - it's off-by-1 as static GC static field layout in CoreRT includes EEType already.

2 files changed, 30 insertions, 0 deletions

diff --git a/src/Runtime.Base/src/System/Object.cs b/src/Runtime.Base/src/System/Object.cs
index 7d5475228..2e541f303 100644
--- a/src/Runtime.Base/src/System/Object.cs
+++ b/src/Runtime.Base/src/System/Object.cs
@@ -19,6 +19,7 @@ using System.Runtime.InteropServices;
 
 // TODO: remove when m_pEEType becomes EETypePtr
 using EEType = Internal.Runtime.EEType;
+using ObjHeader = Internal.Runtime.ObjHeader;
 
 namespace System
 {
@@ -69,15 +70,36 @@ namespace System
             }
         }
 
+        internal EETypePtr EETypePtr
+        {
+            get
+            {
+                return new EETypePtr(new IntPtr(m_pEEType));
+            }
+        }
+
         [StructLayout(LayoutKind.Sequential)]
         private class RawData
         {
             public byte Data;
         }
 
+        /// <summary>
+        /// Return beginning of all data (excluding ObjHeader and EEType*) within this object.
+        /// Note that for strings/arrays this would include the Length as well. 
+        /// </summary>
         internal ref byte GetRawData()
         {
             return ref Unsafe.As<RawData>(this).Data;
         }
+
+        /// <summary>
+        /// Return size of all data (excluding ObjHeader and EEType*).
+        /// Note that for strings/arrays this would include the Length as well.
+        /// </summary>
+        internal uint GetRawDataSize()
+        {
+            return EETypePtr.BaseSize - (uint)sizeof(ObjHeader) - (uint)sizeof(EEType*);
+        }
     }
 }
diff --git a/src/Runtime.Base/src/System/Runtime/EETypePtr.cs b/src/Runtime.Base/src/System/Runtime/EETypePtr.cs
index b8bc5e4cd..26355a84a 100644
--- a/src/Runtime.Base/src/System/Runtime/EETypePtr.cs
+++ b/src/Runtime.Base/src/System/Runtime/EETypePtr.cs
@@ -49,6 +49,14 @@ namespace System
             throw new NotImplementedException();
         }
 #endif
+
+        internal unsafe uint BaseSize
+        {
+            get
+            {
+                return ToPointer()->BaseSize;
+            }
+        }
     }
 }