Remove jobserver from Session

It is effectively a global resource and the jobserver::Client in Session
was a clone of GLOBAL_CLIENT anyway.

Cargo.lock

@@ -3507,7 +3507,6 @@ dependencies = [
  "cc",
  "either",
  "itertools",
- "jobserver",
  "libc",
  "object 0.36.5",
  "pathdiff",

compiler/rustc_codegen_cranelift/src/concurrency_limiter.rs

@@ -1,8 +1,7 @@
 use std::sync::{Arc, Condvar, Mutex};
 
-use jobserver::HelperThread;
+use rustc_data_structures::jobserver::{self, HelperThread};
 use rustc_errors::DiagCtxtHandle;
-use rustc_session::Session;
 
 // FIXME don't panic when a worker thread panics
 
@@ -14,14 +13,13 @@ pub(super) struct ConcurrencyLimiter {
 }
 
 impl ConcurrencyLimiter {
-    pub(super) fn new(sess: &Session, pending_jobs: usize) -> Self {
+    pub(super) fn new(pending_jobs: usize) -> Self {
         let state = Arc::new(Mutex::new(state::ConcurrencyLimiterState::new(pending_jobs)));
         let available_token_condvar = Arc::new(Condvar::new());
 
         let state_helper = state.clone();
         let available_token_condvar_helper = available_token_condvar.clone();
-        let helper_thread = sess
+        let helper_thread = jobserver::client()
-            .jobserver
             .clone()
             .into_helper_thread(move |token| {
                 let mut state = state_helper.lock().unwrap();
@@ -113,7 +111,7 @@ impl Drop for ConcurrencyLimiterToken {
 }
 
 mod state {
-    use jobserver::Acquired;
+    use rustc_data_structures::jobserver::Acquired;
 
     #[derive(Debug)]
     pub(super) struct ConcurrencyLimiterState {

compiler/rustc_codegen_cranelift/src/driver/aot.rs

@@ -679,7 +679,7 @@ pub(crate) fn run_aot(
             metadata_module: None,
             metadata,
             crate_info: CrateInfo::new(tcx, target_cpu),
-            concurrency_limiter: ConcurrencyLimiter::new(tcx.sess, 0),
+            concurrency_limiter: ConcurrencyLimiter::new(0),
         });
     };
 
@@ -711,7 +711,7 @@ pub(crate) fn run_aot(
             CguReuse::PreLto | CguReuse::PostLto => false,
         });
 
-    let concurrency_limiter = IntoDynSyncSend(ConcurrencyLimiter::new(tcx.sess, todo_cgus.len()));
+    let concurrency_limiter = IntoDynSyncSend(ConcurrencyLimiter::new(todo_cgus.len()));
 
     let modules = tcx.sess.time("codegen mono items", || {
         let mut modules: Vec<_> = par_map(todo_cgus, |(_, cgu)| {

compiler/rustc_codegen_cranelift/src/lib.rs

@@ -12,7 +12,6 @@
 #![warn(unused_lifetimes)]
 // tidy-alphabetical-end
 
-extern crate jobserver;
 #[macro_use]
 extern crate rustc_middle;
 extern crate rustc_abi;

compiler/rustc_codegen_ssa/Cargo.toml

@@ -11,7 +11,6 @@ bitflags = "2.4.1"
 cc = "1.1.23"
 either = "1.5.0"
 itertools = "0.12"
-jobserver = "0.1.28"
 pathdiff = "0.2.0"
 regex = "1.4"
 rustc_abi = { path = "../rustc_abi" }

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -6,9 +6,9 @@ use std::sync::Arc;
 use std::sync::mpsc::{Receiver, Sender, channel};
 use std::{fs, io, mem, str, thread};
 
-use jobserver::{Acquired, Client};
 use rustc_ast::attr;
 use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
+use rustc_data_structures::jobserver::{self, Acquired};
 use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::profiling::{SelfProfilerRef, VerboseTimingGuard};
 use rustc_errors::emitter::Emitter;
@@ -456,7 +456,6 @@ pub(crate) fn start_async_codegen<B: ExtraBackendMethods>(
     metadata_module: Option<CompiledModule>,
 ) -> OngoingCodegen<B> {
     let (coordinator_send, coordinator_receive) = channel();
-    let sess = tcx.sess;
 
     let crate_attrs = tcx.hir().attrs(rustc_hir::CRATE_HIR_ID);
     let no_builtins = attr::contains_name(crate_attrs, sym::no_builtins);
@@ -477,7 +476,6 @@ pub(crate) fn start_async_codegen<B: ExtraBackendMethods>(
         shared_emitter,
         codegen_worker_send,
         coordinator_receive,
-        sess.jobserver.clone(),
         Arc::new(regular_config),
         Arc::new(metadata_config),
         Arc::new(allocator_config),
@@ -1093,7 +1091,6 @@ fn start_executing_work<B: ExtraBackendMethods>(
     shared_emitter: SharedEmitter,
     codegen_worker_send: Sender<CguMessage>,
     coordinator_receive: Receiver<Box<dyn Any + Send>>,
-    jobserver: Client,
     regular_config: Arc<ModuleConfig>,
     metadata_config: Arc<ModuleConfig>,
     allocator_config: Arc<ModuleConfig>,
@@ -1145,7 +1142,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
     // get tokens on `coordinator_receive` which will
     // get managed in the main loop below.
     let coordinator_send2 = coordinator_send.clone();
-    let helper = jobserver
+    let helper = jobserver::client()
         .into_helper_thread(move |token| {
             drop(coordinator_send2.send(Box::new(Message::Token::<B>(token))));
         })

compiler/rustc_data_structures/src/jobserver.rs

@@ -1,6 +1,6 @@
 use std::sync::{LazyLock, OnceLock};
 
-pub use jobserver_crate::Client;
+pub use jobserver_crate::{Acquired, Client, HelperThread};
 use jobserver_crate::{FromEnv, FromEnvErrorKind};
 
 // We can only call `from_env_ext` once per process

compiler/rustc_session/src/session.rs

@@ -8,7 +8,6 @@ use std::{env, fmt, io};
 
 use rustc_data_structures::flock;
 use rustc_data_structures::fx::{FxHashMap, FxIndexSet};
-use rustc_data_structures::jobserver::{self, Client};
 use rustc_data_structures::profiling::{SelfProfiler, SelfProfilerRef};
 use rustc_data_structures::sync::{
     DynSend, DynSync, Lock, Lrc, MappedReadGuard, ReadGuard, RwLock,
@@ -154,10 +153,6 @@ pub struct Session {
     /// Data about code being compiled, gathered during compilation.
     pub code_stats: CodeStats,
 
-    /// Loaded up early on in the initialization of this `Session` to avoid
-    /// false positives about a job server in our environment.
-    pub jobserver: Client,
-
     /// This only ever stores a `LintStore` but we don't want a dependency on that type here.
     pub lint_store: Option<Lrc<dyn LintStoreMarker>>,
 
@@ -1072,7 +1067,6 @@ pub fn build_session(
         incr_comp_session: RwLock::new(IncrCompSession::NotInitialized),
         prof,
         code_stats: Default::default(),
-        jobserver: jobserver::client(),
         lint_store: None,
         registered_lints: false,
         driver_lint_caps,