Does Mono Mkbundle Produce Native Code

Question

The normal EXE's generated by mono are in IL.I want to generate Native Executable,does using mkbundle produce native Exe's or should i use Mono AOT.

Answer 1

Yes, mkbundle produces native executables. For example, on Linux, here is my .NET assembly:

file Agent.exe
Agent.exe: PE32 executable (console) Intel 80386, Mono/.Net assembly, for MS Windows

I tell mkbundle to compile it to a native executable (here I have to add Common.dll which is a dependency to my Agent.exe assembly):

mkbundle --deps -o Agent Agent.exe Common.dll
   OS is: Linux
   Sources: 3 Auto-dependencies: True
   embedding: Agent/bin/Debug/Agent.exe
   embedding: Agent/bin/Debug/Common.dll
   embedding: /usr/lib/mono/4.5/mscorlib.dll
   embedding: /usr/lib/mono/gac/System.Runtime.Serialization/4.0.0.0__b77a5c561934e089/System.Runtime.Serialization.dll
   embedding: /usr/lib/mono/gac/System.Xml/4.0.0.0__b77a5c561934e089/System.Xml.dll
   embedding: /usr/lib/mono/gac/System/4.0.0.0__b77a5c561934e089/System.dll
   embedding: /usr/lib/mono/gac/Mono.Security/4.0.0.0__0738eb9f132ed756/Mono.Security.dll
   embedding: /usr/lib/mono/gac/System.Configuration/4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
   embedding: /usr/lib/mono/gac/System.Security/4.0.0.0__b03f5f7f11d50a3a/System.Security.dll
   embedding: /usr/lib/mono/gac/System.Core/4.0.0.0__b77a5c561934e089/System.Core.dll
   embedding: /usr/lib/mono/gac/Mono.Posix/4.0.0.0__0738eb9f132ed756/Mono.Posix.dll
   embedding: /usr/lib/mono/gac/System.Data.Linq/4.0.0.0__b77a5c561934e089/System.Data.Linq.dll
   embedding: /usr/lib/mono/gac/System.Data/4.0.0.0__b77a5c561934e089/System.Data.dll
   embedding: /usr/lib/mono/gac/Mono.Data.Tds/4.0.0.0__0738eb9f132ed756/Mono.Data.Tds.dll
   embedding: /usr/lib/mono/gac/System.Transactions/4.0.0.0__b77a5c561934e089/System.Transactions.dll
   embedding: /usr/lib/mono/gac/System.EnterpriseServices/4.0.0.0__b03f5f7f11d50a3a/System.EnterpriseServices.dll
Compiling:
as -o temp.o temp.s 
cc -ggdb -o Agent -Wall temp.c `pkg-config --cflags --libs mono-2`  temp.o
Done

Now, Let's run the file command again, this time against the generated 'Agent' binary:

file Agent
Agent: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, BuildID[sha1]=698384c13208eccc609e5a573deeb09ed3420a29, not stripped

Note : this native binary still depends on libmono (the Mono runtime library), so it won't work on a machine without a working Mono installation.

You can however embed libmono into your binary and get an independant, self-contained executable by using mkbundle --static option.

Answer 2

• http://www.mono-project.com/archived/guiderunning_mono_applications/#bundles

mkbundle generates an executable program that will contain static copies of the assemblies listed on the command line.

I doubt this is what you expected from a word "native exe." Here's a small experiment:

Test01.cs

using System;
public class Test01 {
  public static void Main()
  {
    Console.WriteLine("Hello, world!");
    Console.WriteLine("Hello, world!");
    Console.WriteLine("Hello, world!");
  }
}

The output MSIL should contain three pairs of ldstr and call instructions, and the terminating ret instruction. Their opcodes are 0x72, 0x28 and 0x2a, respectively:

• https://msdn.microsoft.com/en-us/library/system.reflection.emit.opcodes_fields%28v=vs.110%29.aspx

Let's check the hex dump (grep -P allows us to use non-greedy match *?)

$ od -t x1 -w9999999 Test01.exe | grep -o -P 72.*?28.*?2a
...
72 01 00 00 70 28 01 00 00 0a 72 01 00 00 70 28 01 00 00 0a 72 01 00 00 70 28 01 00 00 0a 2a

Now we know the MSIL byte sequence corresponding to the above Test01.cs. And the output from mkbundle contains exactly the same byte sequence:

$ mkbundle -o Test01 Test01.exe --deps
...
$ od -t x1 -w9999999 Test01 | fgrep -o '72 01 00 00 70 28 01 00 00 0a 72 01 00 00 70 28 01 00 00 0a 72 01 00 00 70 28 01 00 00 0a 2a'
72 01 00 00 70 28 01 00 00 0a 72 01 00 00 70 28 01 00 00 0a 72 01 00 00 70 28 01 00 00 0a 2a

Unfortunately I don't think mkbundle(1) has any options like --full-aot. So AOT and creating a (static) bundle exe is mutually exclusive as of now (Mono 4.2.2.30)