3.1% allocations of TypeConversions

[Youssef1313]

Allocations happen here:

roslyn/src/Compilers/CSharp/Portable/Symbols/ReducedExtensionMethodSymbol.cs

Line 51 in 86156fa

var conversions = new TypeConversions(method.ContainingAssembly.CorLibrary);

Does it make sense to introduce a lazy TypeConversions property on assembly symbol, and use it instead of creating TypeConversions instances?

[Youssef1313]

Trace in https://developercommunity.visualstudio.com/t/Performance-trace-for-Roslyn-team/10413054

[jaredpar]

Does it make sense to introduce a lazy TypeConversions property on assembly symbol, and use it instead of creating TypeConversions instances?

Our AssemblySymbol instances are long lived hence that extra allocation will effectively just grow the size of every instance. Not sure that is the best approach. Did you consider attaching it to say the compilation or another symbol relevant to the scenario?

@CyrusNajmabadi

[CyrusNajmabadi]

The symbols are long lived. But there are relatively few of them. I think it would likely be fine for either hte assembly-symbol (or the compilation) to have such a cache where this is held onto, instead of continaully recreating it :)