rust/library/std
Alex Crichton c6eea222a9 std: Add a variant of thread locals with const init
This commit adds a variant of the `thread_local!` macro as a new
`thread_local_const_init!` macro which requires that the initialization
expression is constant (e.g. could be stuck into a `const` if so
desired). This form of thread local allows for a more efficient
implementation of `LocalKey::with` both if the value has a destructor
and if it doesn't. If the value doesn't have a destructor then `with`
should desugar to exactly as-if you use `#[thread_local]` given
sufficient inlining.

The purpose of this new form of thread locals is to precisely be
equivalent to `#[thread_local]` on platforms where possible for values
which fit the bill (those without destructors). This should help close
the gap in performance between `thread_local!`, which is safe, relative
to `#[thread_local]`, which is not easy to use in a portable fashion.
2021-04-16 09:21:38 -07:00
..
benches
src std: Add a variant of thread locals with const init 2021-04-16 09:21:38 -07:00
tests
build.rs
Cargo.toml Auto merge of #83776 - jyn514:update-stdarch-docs, r=Amanieu 2021-04-12 18:29:25 +00:00