It improves compile time in `--release` mode quite a bit, it doesn't
really slow things down and, conceptually, it seems closer to what we
want the physical architecture to look like (we don't want to
monomorphise EVERYTHING in a single leaf crate).
This change:
- introduces `compute_crate_def_map` query and renames
`CrateDefMap::crate_def_map_query` for consistency,
- annotates `crate_def_map` as `salsa::transparent` and adds a
top-level `crate_def_map` wrapper function around that starts the
profiler and immediately calls into `compute_crate_def_map` query.
This allows us to better understand where we spent the time, in
particular, how much is spent in the recomputaiton and how much in
salsa.
Example output (where we don't actually re-compute anything, but the
query still takes a non-trivial amount of time):
```
211ms - handle_inlay_hints
150ms - get_inlay_hints
150ms - SourceAnalyzer::new
65ms - def_with_body_from_child_node
65ms - analyze_container
65ms - analyze_container
65ms - Module::from_definition
65ms - Module::from_file
65ms - crate_def_map
1ms - parse_macro_query (6 calls)
0ms - raw_items_query (1 calls)
64ms - ???
```
Signed-off-by: Michal Terepeta <michal.terepeta@gmail.com>
The current system with AstIds has two primaraly drawbacks:
* It is possible to manufacture IDs out of thin air.
For example, it's possible to create IDs for items which are not
considered in CrateDefMap due to cfg. Or it is possible to mixup
structs and unions, because they share ID space.
* Getting the ID of a parent requires a secondary index.
Instead, the plan is to pursue the more traditional approach, where
each items stores the id of the parent declaration. This makes
`FromSource` more awkward, but also more correct: now, to get from an
AST to HIR, we first do this recursively for the parent item, and the
just search the children of the parent for the matching def
