bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Auto merge of #101313 - SparrowLii:mk_attr_id, r=cjgillot

Browse source 
make `mk_attr_id` part of `ParseSess`

Updates #48685

The current `mk_attr_id` uses the `AtomicU32` type, which is not very efficient and adds a lot of lock contention in a parallel environment.

This PR refers to the task list in #48685, uses `mk_attr_id` as a method of the `AttrIdGenerator` struct, and adds a new field `attr_id_generator` to `ParseSess`.

`AttrIdGenerator` uses the `WorkerLocal`, which has two advantages: 1. `Cell` is more efficient than `AtomicU32`, and does not increase any lock contention. 2. We put the index of the work thread in the first few bits of the generated `AttrId`, so that the `AttrId` generated in different threads can be easily guaranteed to be unique.

cc `@cjgillot`
This commit is contained in:
bors 2022-09-14 20:52:18 +00:00
commit 750bd1a7ff
13 changed files with 111 additions and 27 deletions
Download patch file Download diff file Expand all files Collapse all files

4
compiler/rustc_ast/src/ast.rs
View file

@ -2524,8 +2524,8 @@ impl<S: Encoder> Encodable<S> for AttrId {
}
impl<D: Decoder> Decodable<D> for AttrId {
fn decode(_: &mut D) -> AttrId {
crate::attr::mk_attr_id()
default fn decode(_: &mut D) -> AttrId {
panic!("cannot decode `AttrId` with `{}`", std::any::type_name::<D>());
}
}