Roslyn Analyzer Discussion

[ketanpkolte]

Discussion regarding rules of diagnostics for BDN, new rules and Code samples

[ketanpkolte]

Currently I am writing a Roslyn analyzer for BDN and would like to know about some good Rules that I can apply for diagnostics.

Some Rules that I have written till now are:
Classes containing [Benchmark] must be UnSealed and Public
Methods attributed with [Benchmark] must be parameterless

[timcassell]

Methods attributed with [Benchmark] must be parameterless

This is not true. Benchmarks may contain parameters, but they must have the [Arguments] or [ArgumentsSource] attribute. https://benchmarkdotnet.org/articles/features/parameterization.html#sample-introarguments

[ketanpkolte]

I would like to know more about benchmarking Generic methods, since BDN allows to benchmark them only if certain criteria are met.
I wanted to confirm these two examples:

'''public class InvalidGenericMethodBenchmark
{
[Params(100, 200, 300)]
public int N;

 [Benchmark]
 public void BenchmarkInvalidGenericMethod()
 {
     InvalidGenericMethod(N);
 }

 public void InvalidGenericMethod<T>(T value) where T : new()
 {
     T instance = new T();
 }

}'''

'''public class ValidGenericMethodBenchmark
{
[Params(100, 200, 300)]
public int N;

 [Benchmark]
 public void BenchmarkGenericMethod()
 {
     GenericMethod<int>(N);
 }

 public void GenericMethod<T>(T value)
 {
     // Simulate some work
     for (int i = 0; i < 1000; i++)
     {
         var temp = value;
     }
 }

}'''

[timcassell]

Currently, methods annotated with [Benchmark] attribute may not be generic. Generic classes may have benchmarks, as long as the class is annotated with [GenericTypeArguments] attribute. https://benchmarkdotnet.org/articles/samples/IntroGenericTypeArguments.html

We do not care if other methods are generic that are called by the benchmark method.

[timcassell]

I recommend reading through the documentation and (especially) the existing validators source code.

[ketanpkolte]

I went through the documents mentioned i wanted to know about possible invalid genericTypeAttribute, as mentioned in my code example

[timcassell]

The number of types in the attribute must match the number of generic type arguments on the type. I think that's the only validation necessary for it.

[Edit] And a generic class containing benchmarks must have at least one of that attribute.