1. Self-Contained CLI Assemblies Dipl.-Inf. Bernhard Rabe Operating Systems & Middleware Group Hasso-Plattner-Institute University of Potsdam

2. Outline • Motivation • Self-contained Assemblies • Micro.NET • Adaptive Linking • Conclusions .NET Technologies'2006, Plzeň

3. Motivation • Common Language Infrastructure (CLI) features: • Loose coupling • Dynamic linking is required at load time • fusion engine (.dll vs. .exe) • Byte code consistency is verifiable • Execution behavior depends on Base Class Library (BCL) implementation (.NET, Rotor, Mono, …) • Comprehensive class library • High memory requirements of runtime environment .NET Technologies'2006, Plzeň

4. C# Example public static int Main(string[] args) { Object obj=new Object(); return 1; } .NET Technologies'2006, Plzeň

5. AssemblyRef Assembly mscorlib B7 7A 5C 56 19 34 E0 89 mscorlib TypeDef TypeRef System.Object System.Array System.Object MemberRef .ctor MethodDef Equals .ctor ret Dynamic Linking usercode.exe mscorlib.dll newobj 0x0a000001 pop ldc.i4.1 ret Main .ctor .NET Technologies'2006, Plzeň

6. Micro.NET • CLR library independent deployment format • Self-contained assemblies • IL interpreter for small embedded devices (Lego Mindstorm) • Micro.NET deals with .NET for resource limited systems • memory • processing power • … .NET Technologies'2006, Plzeň

7. Runtime Memory Footprint • Assembly • Custom Library assemblies • Base Class Library • CLR Self-contained Assembly .NET Technologies'2006, Plzeň

8. Self-contained Assemblies • No external references • BCL independent • Fewer memory consumption • Metadata of assemblies • Reduced startup delay • type resolving • Optimizations under investigation • Whole program analysis • Metadata • Optimizations without Common Language Runtime (CLR) modifications .NET Technologies'2006, Plzeň

9. Avoiding Dynamic Linking • Compile to native code e.g. CIL front-end • no VM features: gc, sandbox • code verification is challenging • platform dependent • Reduce the number of assemblies/references • combine assemblies • Streamlining dynamic linking .NET Technologies'2006, Plzeň

10. Configuration Linker tool Adaptive Linking library library usercode.exe self-contained assembly Base Class Library .NET Technologies'2006, Plzeň

11. Adaptive Linking • PERWAPI library* based linker tool • Combine referenced types into a self-contained assembly • Types are processed recursively • Fine granular linking (type level) *Queensland University of Technology (QUT), Australia .NET Technologies'2006, Plzeň

12. CIL of C# example (excerpt) .class a{ .method public hidebysig specialname rtspecialname instance void .ctor() cil managed {…} .method public hidebysig static void Main(string[] args) cil managed{ .entrypoint .maxstack 1 newobj instance void [mscorlib]System.Object::.ctor() pop ldc.i4.1 ret } } .NET Technologies'2006, Plzeň

13. Self-contained (excerpt) .class Hello { .method public hidebysig specialname rtspecialname instance void .ctor() cil managed {…} .method public hidebysig static void Main(string[] args) cil managed{ … newobj instance void System.Object::.ctor() … } } .class System.Object{ .method public hidebysig specialname rtspecialname instance void .ctor() cil managed {…} .method family hidebysig virtual instance void Finalize() cil managed{…} } .NET Technologies'2006, Plzeň

14. Results • PoCs run on Rotor, Mono, and Portable.NET without CLR modfications • None CLR portable features • internalcall • System.Object::Equals(object obj) .NET vs. Mono • runtime • pinvokeimpl • Necessity for an highly portable BCL • Source for Self-contained Assemblies .NET Technologies'2006, Plzeň

15. Conclusion • Self-contained assemblies • .NET on resource constrained systems • reduced resource consumption • Optimized deployment format for resource limited systems • No CLR modifications required .NET Technologies'2006, Plzeň