Make QCalls respect the EntryPoint property

[jkoritzinsky]

Fixes #59823

Move QCalls to use a similar registration mechanism as the libraries that are bundled in the single file host. All QCalls are now C-style functions and the runtimes now respect the EntryPoint property.

This will enable Mono AOT to more easily resolve QCalls if Mono decides to use them (hopefully this will make using QCalls in Mono more attractive).

Additionally, by making QCalls respect the EntryPoint property, we will be able to move all QCalls to use the DllImportGenerator even for non-blittable QCalls.

[vargaz]

The mono changes look ok. Does this mean that the EntryPoint property is mandatory on qcalls ? Should the runtime code verify that ?

[elinor-fung]

Does this mean that the EntryPoint property is mandatory on qcalls ?

That should not be the case. If EntryPoint is not set, the method name is used. I expect @jkoritzinsky added the prefixes for existing QCalls to have reasonable differentiation on the native side, so EntryPoint is set on them since the method name is not the desired entry point.

[jkoritzinsky]

@vargaz, @elinor-fung is correct. I've added the EntryPoint property where the managed and native QCall method names differ. We have a few that are identical, so there were no changes for those needed on the managed side.

[jkotas]

Thanks!

[elinor-fung]

Is there a reason to keep the Native suffix on a few of the prefixes (AssemblyNative, ThreadNative, MarshalNative) instead of leaving it off like most of the others?

[jkoritzinsky]

No particular reason. I just did most of this change with a mechanical find-replace, so I didn't want to go back and update these manually since some of these classes (mainly AssemblyNative) are used by multiple managed types.

[jkoritzinsky]

I'll leave these names as-is for now. We can clean this up in a future PR.

[am11]

it sounds like CharSet and EntryPoint are mandatory. would it be more accurate to say:

- // All QCalls should have the following DllImport attribute
+ // All QCalls should have the following DllImport attribute (with or without `EntryPoint`)
or simply:
+ // An example of QCall DllImport

[jkoritzinsky]

CharSet and EntryPoint aren't mandatory, but the majority of cases will require at least one of them. We can update the docs/examples if necessary, but I think the guidance is good as a starting place.