Mark unaligned reads in NativeFormatReader as unaligned for the JIT

src/coreclr/nativeaot/Runtime.Base/src/System/Runtime/CompilerServices/Unsafe.cs

@@ -109,5 +109,15 @@ public static ref T AsRef<T>(in T source)
         {
             throw new PlatformNotSupportedException();
         }
+
+        /// <summary>
+        /// Reads a value of type <typeparamref name="T"/> from the given location.
+        /// </summary>
+        [Intrinsic]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static T ReadUnaligned<T>(void* source)
+        {
+            throw new PlatformNotSupportedException();
+        }
     }
 }

src/coreclr/tools/Common/Internal/NativeFormat/NativeFormatReader.Primitives.cs

@@ -8,6 +8,7 @@
 // ---------------------------------------------------------------------------
 
 using System.Diagnostics;
+using System.Runtime.CompilerServices;
 
 namespace Internal.NativeFormat
 {
@@ -23,21 +24,21 @@ public static byte ReadUInt8(ref byte* stream)
 
         public static ushort ReadUInt16(ref byte* stream)
         {
-            ushort result = *(ushort*)(stream); // Assumes little endian and unaligned access
+            ushort result = Unsafe.ReadUnaligned<ushort>(stream); // Assumes little endian and unaligned access
             stream += 2;
             return result;
         }
 
         public static uint ReadUInt32(ref byte* stream)
         {
-            uint result = *(uint*)(stream); // Assumes little endian and unaligned access
+            uint result = Unsafe.ReadUnaligned<uint>(stream); // Assumes little endian and unaligned access
             stream += 4;
             return result;
         }
 
         public static ulong ReadUInt64(ref byte* stream)
         {
-            ulong result = *(ulong*)(stream); // Assumes little endian and unaligned access
+            ulong result = Unsafe.ReadUnaligned<ulong>(stream); // Assumes little endian and unaligned access
             stream += 8;
             return result;
         }