[llvm] Store sysreg names in-line with their descriptors. (PR #119157)

[Owen Anderson via llvm-commits]

resistor wrote:

I don't see a straightforward path to moving this to a string table. I did some prototyping of attempting to move GenericTable to use string tables for all string values, but it ends up being tricky for a few reasons:
* TableGen doesn't have a very strong type-system, so it's very hard to determine which things should be put in a string table.
* Some of the users of GenericTable don't have an easy way to recover the base pointer for the string table.
* Introducing SequenceToOffsetTable is mechanically difficult in the SearchableTableEmitter because it wants to be able to sort things lexicographically earlier than it would be natural to build the SequenceToOffsetTable.

This seems like it could be an area for future enhancement if someone wants to do some major refactoring, but it's not a simple add-on improvement.

https://github.com/llvm/llvm-project/pull/119157