Caching lambda expressions used to manipulate objects using reflection

[ekolis]

Sorry if this is the wrong place to suggest this; I've never tried to contribute to .NET in this way before!

Anyway, in a project of mine I wrote a serializer that relied heavily on reflection, and it was horribly slow. However I was able to speed it up quite a bit by creating, compiling, and caching a lambda expression for each property getter and setter of each class I was serializing. I was thinking something like this could be built into the CLR, to make reflection much faster. I don't know what this does to memory usage, but perhaps at least there could be a static flag to set on some class somewhere, or a core library which does what I was doing in case anyone needs it?

[mattwarren]

I agree this would be nice to have, at the moment you have to use IL.Emit or Expression trees to speed things up, which aren't straight forward (although libraries like Sigil can help)

It's worth pointing out that Java has this feature, it's called 'inflation', however it can cause memory issues

[madelson]

According to the link @mattwarren posted, in Java the memory issues stem from having to generate a whole new class each time reflection on a method is optimized. In .NET where we have support for delegates, it seems like the overhead could potentially be lower.

[steveharter]

The current plan of record for 5.0 is to provide new APIs to support faster ways to call getters, setters and constructors which a serializer would need to do. The new APIs are covered by #23716. Using expressions doesn't support AOT scenarios so it is not a path we want to invest in (at least for serializers).

A discussion around mechanisms to call getters, setters and constructors is discussed in the design doc at dotnet/designs#113.