this makes three changes:
- all callsites of `toolchain::command` are changed to use
`command(path, extra_env)`, instead of manually adding the env after
the fact.
- all `map<str, str>` are changed to `map<str, option<str>>`.
- `command` checks for None and calls `env_remove` if so.
this caught several places where environment variables weren't being
propagated:
- when running `rustc --print=target-libdir`
- when running `cargo rustc -- --print=target-spec-json`
- when running the custom DiscoverLinkedProjects config. I *think* this
is for use with non-cargo build systems, so I didn't change it.
I expected this to be faster (due to less allocations and better cache locality), but benchmarked it is not (neither it is slower). Memory usage, however, drops by ~50mb (of `analysis-stats .`). I guess tt construction is just not hot.
This also simplifies using even less memory for token trees by compressing equal span, which I plan to do right after.
Some workflows are more easily expressed with a flat tt, while some are better expressed with a tree. With the right helpers, though (which was mostly a matter of trial and error), even the worst workflows become very easy indeed.
When viewing traces, it's slightly confusing when the span name doesn't
match the function name. Ensure the names are consistent.
(It might be worth moving most of these to use #[tracing::instrument]
so the name can never go stale. @davidbarsky suggested that is marginally
slower, so I've just done the simple change here.)
This commit also adds `tracing` to NotificationDispatcher/RequestDispatcher,
bumps `rust-analyzer-salsa` to 0.17.0-pre.6, `always-assert` to 0.2, and
removes the homegrown `hprof` implementation in favor of a vendored
tracing-span-tree.
Implement proc-macro-api versioning
So as it stands, we can't really change the proc-macro-api protocol at all without breaking all proc-macro servers again. To somewhat alleviate this we can move the supported ABI mess over to the proc-macro-api now by supporting multiple versions there (versions defined by us at least, not by rustc). Since the proc-macro-api protocol has no versioning scheme at the moment though, the best we can do here is add a new request to query the version from a server. Due to how the server currently works though, if it encounters an unknown request it will exit, meaning we can check if it is a server without support by checking if it exited after our version check request, that way we can support the current circulating server as well.
We need this since our span type will change from `TokenId` to something else at some point, but for that to work we need to comply with that the server expects. So knowing the version the server is using we can decide whether to send our new span data, or the tokenid (assuming we keep that information with our span data as well, alternatively we send irrelevant tokenids). That way we can keep old servers working while the user installations slowly migrate to newer servers that support the new spandata.
