slow CodeDom

microsoft.public.dotnet.framework

1 Oct 2006 5:47 AM

geoff phair

We've done an AI app which generates lots of code source, then runs the code
using its own little interpreter and works fine - all in vb 2003. I've done a
new version using Codedom, expecting a blindingly fast improvement. It was
reasonably painless to implement too.

It's approximately 10 times slower!

The compilation takes 3 times longer than the whole previous version. This I
can understand(I think). My problem is that running the main method in the
resulting assembly takes 4 times longer than the clunky interpreter on the
same code!

Why is this?

I also get InvalidProgramExceptions which I gather are due to the fact that
some of the statements are very long - 1000chrs+ with lots of braces.

details -

The code to be compiled is pretty simple - dll, one class, one method.
The method contains 1000+ statements all of which look like this, but may be
up to 1000 chrs. v1 is a simple variable, type single.

        Results(f, 411) = ((Sin(v1 / -4.0) - v1) * (v1 + Sin(v1 - -9.0)))
        .....
        return Results

Dim provider As VBCodeProvider = New VBCodeProvider
Dim compiler As ICodeCompiler = provider.CreateCompiler()
Try
    ' Build the parameters for source compilation.
    Dim cp As New CompilerParameters
    ' Add an assembly reference.
    cp.ReferencedAssemblies.Add("System.dll")
    'cp.ReferencedAssemblies.Add("Microsoft.VisualBasic.dll")
    cp.GenerateInMemory = True
    ' Generate a class library.
    cp.GenerateExecutable = False
    cp.IncludeDebugInformation = False

    ' Invoke compilation.
    Dim cr As CompilerResults = compiler.CompileAssemblyFromSource(cp,
strSource)

    A=cr.CompiledAssembly

Dim P As Type, M As MethodInfo, obj As Object, results(,) As Single
      'Get the type to use.
      P = A.GetType("TempClass")
      'Get the method to call.
      M = P.GetMethod("ResultsGet")
      'Create an instance
      obj = Activator.CreateInstance(P)

      Return CType(M.Invoke(obj, New Object() {fcases, indscount}), Single(,))

fcases is a 2d array of single and indscount is an integer