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Diffstat (limited to '')
-rw-r--r-- | compiler/rustc_data_structures/src/jobserver.rs | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/compiler/rustc_data_structures/src/jobserver.rs b/compiler/rustc_data_structures/src/jobserver.rs new file mode 100644 index 000000000..09baa3095 --- /dev/null +++ b/compiler/rustc_data_structures/src/jobserver.rs @@ -0,0 +1,40 @@ +pub use jobserver_crate::Client; +use std::sync::LazyLock; + +// We can only call `from_env` once per process + +// Note that this is unsafe because it may misinterpret file descriptors +// on Unix as jobserver file descriptors. We hopefully execute this near +// the beginning of the process though to ensure we don't get false +// positives, or in other words we try to execute this before we open +// any file descriptors ourselves. +// +// Pick a "reasonable maximum" if we don't otherwise have +// a jobserver in our environment, capping out at 32 so we +// don't take everything down by hogging the process run queue. +// The fixed number is used to have deterministic compilation +// across machines. +// +// Also note that we stick this in a global because there could be +// multiple rustc instances in this process, and the jobserver is +// per-process. +static GLOBAL_CLIENT: LazyLock<Client> = LazyLock::new(|| unsafe { + Client::from_env().unwrap_or_else(|| { + let client = Client::new(32).expect("failed to create jobserver"); + // Acquire a token for the main thread which we can release later + client.acquire_raw().ok(); + client + }) +}); + +pub fn client() -> Client { + GLOBAL_CLIENT.clone() +} + +pub fn acquire_thread() { + GLOBAL_CLIENT.acquire_raw().ok(); +} + +pub fn release_thread() { + GLOBAL_CLIENT.release_raw().ok(); +} |