Microsoft.CSharp code could use some refactoring/optimization

[jamesqo]

This program:

public static void Main()
{
    for (int i = 0; i < 1000000000; i++)
    {
        dynamic thing = new object();
        thing.Equals(null);
    }
}

causes many GC marks when run from the Visual Studio profiler within a short period of time. Here's a snapshot from my machine:

Here's the data from the memory profiler about which objects are being allocated the most:

Of course, obviously perf is not the first consideration when using dynamic objects, but it looks like a lot of these could be avoided. I looked a bit further into the Microsoft.CSharp package where this code is coming from, and it looks like the code is somewhat of a mess. It uses a lot of Hungarian notation and classes with COM-style all-caps names. As for perf, here's a random example of where it could be optimized, and also here. As another example, this looks like it could be a struct.

Posting this here as a self-note, since I'm planning to submit a couple of PRs to remedy this in the next couple of weeks.

[karelz]

@jamesqo are you still working on it?

[karelz]

This is too nebulous and generic, we should track specific issues / improvements in the code.
Note: The code is very sensitive to appcompat, so any change in here has to be really worth it and has to be thought through all angles.