DebugInfo: Move new hierarchy into place
Move the specialized metadata nodes for the new debug info hierarchy
into place, finishing off PR22464. I've done bootstraps (and all that)
and I'm confident this commit is NFC as far as DWARF output is
concerned. Let me know if I'm wrong :).
The code changes are fairly mechanical:
- Bumped the "Debug Info Version".
- DIBuilder now creates the appropriate subclass of MDNode.
- Subclasses of DIDescriptor now expect to hold their "MD" counterparts (e.g., DIBasicType expects MDBasicType).
- Deleted a ton of dead code in AsmWriter.cpp and DebugInfo.cpp for printing comments.
- Big update to LangRef to describe the nodes in the new hierarchy. Feel free to make it better.
Testcase changes are enormous. There's an accompanying clang commit on
If you have out-of-tree debug info testcases, I just broke your build.
- upgrade-specialized-nodes.sh is attached to PR22564. I used it to update all the IR testcases.
- Unfortunately I failed to find way to script the updates to CHECK lines, so I updated all of these by hand. This was fairly painful, since the old CHECKs are difficult to reason about. That's one of the benefits of the new hierarchy.
This work isn't quite finished, BTW. The DIDescriptor subclasses are
almost empty wrappers, but not quite: they still have loose casting
checks (see the RETURN_FROM_RAW() macro). Once they're completely
gutted, I'll rename the "MD" classes to "DI" and kill the wrappers. I
also expect to make a few schema changes now that it's easier to reason