mirror
/
rustc-dev-guide
mirror of https://github.com/rust-lang/rustc-dev-guide.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Update some more things and improve wording

This commit is contained in:
Nilstrieb 2022-11-05 15:47:05 +01:00 committed by Joshua Nelson
parent 087224159e
commit 090bd5422d
1 changed files with 10 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
src/query.md
View File

@ -169,12 +169,16 @@ they define both a `provide` and a `provide_extern` function, through
How do you add a new query?
Defining a query takes place in two steps:
1. Specify the query name and its arguments.
1. Declare the query name, its arguments and description.
2. Supply query providers where needed.
To specify the query name and arguments, you simply add an entry to
the big macro invocation in
[`compiler/rustc_middle/src/query/mod.rs`][query-mod], which looks something like:
To declare the query name and arguments, you simply add an entry to
the big macro invocation in [`compiler/rustc_middle/src/query/mod.rs`][query-mod].
Then you need to add a documentation comment to it with some _internal_ description.
Then, provide the `desc` attribute which contains a short description of the query.
This description is shown to the user in query cycles.
This looks something like:
[query-mod]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/query/index.html
@ -182,7 +186,8 @@ the big macro invocation in
rustc_queries! {
/// Records the type of every item.
query type_of(key: DefId) -> Ty<'tcx> {
cache { key.is_local() }
cache_on_disk_if { key.is_local() }
desc { |tcx| "computing the type of `{}`", tcx.def_path_str(key) }
}
...
}
@ -261,21 +266,6 @@ extra methods which are used by the query system.
[QueryConfig]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_query_system/query/config/trait.QueryConfig.html
[QueryDescription]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_query_system/query/config/trait.QueryDescription.html
Queries also have a description, which is specified using the `desc` modifier.
This description is shown to the user when cycle errors happen.
```rust,ignore
rustc_queries! {
Other {
/// Records the type of every item.
query type_of(key: DefId) -> Ty<'tcx> {
desc { |tcx| "computing the type of `{}`", tcx.def_path_str(key) }
}
}
}
```
## External links
Related design ideas, and tracking issues: