debug-info tests are broken after LLVM upgrade

[brson]

http://buildbot.rust-lang.org/builders/auto-linux/builds/808/steps/test/logs/stdio

(Update from Felix: the link above is dead.)

[jdm]

According to echristo, the debug metadata node format changed and the docs weren't updated. Easiest way to unbreak it is to refer to the Clang source as reference.

[emberian]

This would be very nice to have working again.

[pnkfelix]

Nominating for milestone #3, "feature complete."

Though if we expect any tools out there to make use of debug-info, then maybe we should be filing this under milestone #2: "backward compatible." (If I could some way to justify getting it into milestone #1, I would...)

[pnkfelix]

Actually, this bug should be clarified: Is this bug pointing out that:

• there are correct tests that are failing but are currently ignored? (Which is my assumption based on the fact that my attempt to use -Z debug-info yielded assertion failures from llvm.)
• Or is it saying that the current tests are failing because they are not good tests (e.g. that they make incorrect assumptions about the debug info.)

[pnkfelix]

(Moving my nomination request to #6814.)

[jdm]

The bug is pointing out the first point in your list.

[jdm]

Fix0red.