Move System.ValueType.s_seed into System.Runtime.CompilerServices.RuntimeHelpers

[gregg-miskelly]

PR #69723 added a 's_seed' field to System.ValueType. This causes the debugger to show all structs as having static members.

This PR moves the field and the function that used it into RuntimeHelpers.

[ghost]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[gregg-miskelly]

CC @tmat

[jkotas]

This still shows up as clutter in windbg/sos where DebuggerBrowsable does not kick in. For example, !DumpClass on any valuetype will have it:

0:000> !DumpClass /d 00007ffaaba39bb8
Class Name: System.DateTime
...
MT Field Offset Type VT Attr Value Name
00007ffaab8eb050 4000305 9b4 System.Int32 1 static 0 s_seed
00007ffaab8ef8f0 4000396 8 System.UInt64 1 instance _dateData
...

It would be better to move this out of ValueType completely, e.g. to src\coreclr\System.Private.CoreLib\src\System\Runtime\CompilerServices\RuntimeHelpers.CoreCLR.cs.

[jkotas]

I can move it around if you do not have time to do it.

[gregg-miskelly]

@jkotas Do you mean to move just the field to RuntimeHelpers? Or the field and all the code that uses it? If the later, should I delete the method in ValueType? Or just have the method in ValueType call a method in RuntimeHelpers?

[jkotas]

Move the field and the one method that uses it. Update all callers to call the method in the new place.

[jkotas]

Thank you!