rust/compiler/rustc_ast
bors 750bd1a7ff Auto merge of #101313 - SparrowLii:mk_attr_id, r=cjgillot
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`
2022-09-14 20:52:18 +00:00
..
src Auto merge of #101313 - SparrowLii:mk_attr_id, r=cjgillot 2022-09-14 20:52:18 +00:00
Cargo.toml Replace rustc_data_structures::thin_vec::ThinVec with thin_vec::ThinVec. 2022-08-29 15:42:13 +10:00
README.md docs(rustc_ast): update crate descriptions 2021-11-02 21:11:17 -05:00

The rustc_ast crate contains those things concerned purely with syntax that is, the AST ("abstract syntax tree"), along with some definitions for tokens and token streams, data structures/traits for mutating ASTs, and shared definitions for other AST-related parts of the compiler (like the lexer and macro-expansion).

For more information about how these things work in rustc, see the rustc dev guide: