Add CreateCecilObjectModel extension method as helper for plugin developers.

ILSpy/LoadedAssemblyExtensions.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Text;
@@ -12,6 +13,23 @@ namespace ICSharpCode.ILSpy
 {
 	public static class LoadedAssemblyExtensions
 	{
+		/// <summary>
+		/// This method creates a Cecil object model from a PEFile. It is intended as helper method for plugins.
+		/// Note that this method is expensive and creates high memory pressure!
+		/// Note that accessing the Cecil objects created by this method after an assembly has been unloaded by ILSpy
+		/// might lead to <see cref="AccessViolationException"/> or similar.
+		/// </summary>
+		/// <remarks>Use only as last resort if there is something missing in the official ILSpy API.
+		/// Consider creating an issue at https://github.com/icsharpcode/ILSpy/issues/new
+		/// and discussing the problem with us.</remarks>
+		public unsafe static Mono.Cecil.ModuleDefinition CreateCecilObjectModel(this PEFile file)
+		{
+			if (!file.Reader.IsEntireImageAvailable)
+				throw new InvalidOperationException("Need full image to create Cecil object model!");
+			var image = file.Reader.GetEntireImage();
+			return Mono.Cecil.ModuleDefinition.ReadModule(new UnmanagedMemoryStream(image.Pointer, image.Length));
+		}
+
 		public static IAssemblyResolver GetAssemblyResolver(this PEFile file)
 		{
 			return GetLoadedAssembly(file).GetAssemblyResolver();