Auto merge of #69808 - cjgillot:vtbl, r=pnkfelix

Avoid duplicating code for each query

There are at the moment roughly 170 queries in librustc.
The way `ty::query` is structured, a lot of code is duplicated for each query.
I suspect this to be responsible for a part of librustc'c compile time.

The first part of this PR reduces the amount of code generic on the query,
replacing it by code generic on the key-value types. I can split it out if needed.

In a second part, the non-inlined methods in the `QueryAccessors` and `QueryDescription` traits
are made into a virtual dispatch table. This allows to reduce even more the number of generated
functions.

This allows to save 1.5s on check build, and 10% on the size of the librustc.rlib.
(Attributed roughly half and half).
My computer is not good enough to measure properly compiling time.
I have no idea of the effect on performance. A perf run may be required.

cc #65031

0 files changed, 0 insertions, 0 deletions