Performance test for Cecil loader and hashing.

cecilandhash.cs

using Mono.Cecil;
using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Security.Cryptography;

namespace ConsoleApp1;

public static class Program
{
    private static void RunCecil(
        ReadingMode mode, byte[] image,
        out TimeSpan load, out TimeSpan iterate)
    {
        var parameters = new ReaderParameters(mode)
        {
            InMemory = false,
            ReadWrite = false,
        };

        var sw = new Stopwatch();
        sw.Start();

        using var assembly = AssemblyDefinition.ReadAssembly(
            new MemoryStream(image),
            parameters);

        load = sw.Elapsed;

        var methods = assembly.MainModule.Types.
            SelectMany(t => t.Methods.Cast<MemberReference>().Concat(t.Fields)).
            ToArray();

        iterate = sw.Elapsed - load;
    }
    private static void RunHash(
        HashAlgorithm alg, byte[] image, out TimeSpan calculate)
    {
        var sw = new Stopwatch();
        sw.Start();

        var hash = alg.ComputeHash(new MemoryStream(image));

        calculate = sw.Elapsed;
    }

    public static void Main(string[] args)
    {
        var image = File.ReadAllBytes("mscorlib.dll");

        RunCecil(
            ReadingMode.Deferred, image,
            out var deferredLoad, out var deferredIterate);
        Console.WriteLine($"Cecil deferred: {deferredLoad}, {deferredIterate}, Total={deferredLoad + deferredIterate}");

        RunCecil(
            ReadingMode.Immediate, image,
            out var immediateLoad, out var immediateIterate);
        Console.WriteLine($"Cecil immediate: {immediateLoad}, {immediateIterate}, Total={immediateLoad + immediateIterate}");

        RunHash(
            MD5.Create(),
            image,
            out var md5Calculate);
        Console.WriteLine($"MD5: {md5Calculate}");

        RunHash(
            SHA1.Create(),
            image,
            out var sha1Calculate);
        Console.WriteLine($"SHA1: {sha1Calculate}");

        RunHash(
            SHA256.Create(),
            image,
            out var sha256Calculate);
        Console.WriteLine($"SHA256: {sha256Calculate}");
    }
}

Cecil deferred: 00:00:00.0525979, 00:00:00.0993047, Total=00:00:00.1519026
Cecil immediate: 00:00:00.4901391, 00:00:00.0162472, Total=00:00:00.5063863
MD5: 00:00:00.0129031
SHA1: 00:00:00.0177283
SHA256: 00:00:00.0388692