Improve coordinator channel handling

Remove usage of Any, reduce visibility of fields and remove unused
backend arguments.

Author: bjorn3

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -1,4 +1,3 @@
-use std::any::Any;
 use std::assert_matches::assert_matches;
 use std::marker::PhantomData;
 use std::path::{Path, PathBuf};
@@ -372,8 +371,6 @@ pub struct CodegenContext<B: WriteBackendMethods> {
     /// The incremental compilation session directory, or None if we are not
     /// compiling incrementally
     pub incr_comp_session_dir: Option<PathBuf>,
-    /// Channel back to the main control thread to send messages to
-    pub coordinator_send: Sender<Box<dyn Any + Send>>,
     /// `true` if the codegen should be run in parallel.
     ///
     /// Depends on [`ExtraBackendMethods::supports_parallel()`] and `-Zno_parallel_backend`.
@@ -1122,10 +1119,10 @@ fn start_executing_work<B: ExtraBackendMethods>(
     autodiff_items: &[AutoDiffItem],
     shared_emitter: SharedEmitter,
     codegen_worker_send: Sender<CguMessage>,
-    coordinator_receive: Receiver<Box<dyn Any + Send>>,
+    coordinator_receive: Receiver<Message<B>>,
     regular_config: Arc<ModuleConfig>,
     allocator_config: Arc<ModuleConfig>,
-    tx_to_llvm_workers: Sender<Box<dyn Any + Send>>,
+    tx_to_llvm_workers: Sender<Message<B>>,
 ) -> thread::JoinHandle<Result<CompiledModules, ()>> {
     let coordinator_send = tx_to_llvm_workers;
     let sess = tcx.sess;
@@ -1153,7 +1150,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
     let coordinator_send2 = coordinator_send.clone();
     let helper = jobserver::client()
         .into_helper_thread(move |token| {
-            drop(coordinator_send2.send(Box::new(Message::Token::<B>(token))));
+            drop(coordinator_send2.send(Message::Token::<B>(token)));
         })
         .expect("failed to spawn helper thread");
 
@@ -1187,7 +1184,6 @@ fn start_executing_work<B: ExtraBackendMethods>(
         remark: sess.opts.cg.remark.clone(),
         remark_dir,
         incr_comp_session_dir: sess.incr_comp_session_dir_opt().map(|r| r.clone()),
-        coordinator_send,
         expanded_args: tcx.sess.expanded_args.clone(),
         diag_emitter: shared_emitter.clone(),
         output_filenames: Arc::clone(tcx.output_filenames(())),
@@ -1423,7 +1419,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
                         let (item, _) =
                             work_items.pop().expect("queue empty - queue_full_enough() broken?");
                         main_thread_state = MainThreadState::Lending;
-                        spawn_work(&cgcx, &mut llvm_start_time, item);
+                        spawn_work(&cgcx, coordinator_send.clone(), &mut llvm_start_time, item);
                     }
                 }
             } else if codegen_state == Completed {
@@ -1502,7 +1498,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
                     MainThreadState::Idle => {
                         if let Some((item, _)) = work_items.pop() {
                             main_thread_state = MainThreadState::Lending;
-                            spawn_work(&cgcx, &mut llvm_start_time, item);
+                            spawn_work(&cgcx, coordinator_send.clone(), &mut llvm_start_time, item);
                         } else {
                             // There is no unstarted work, so let the main thread
                             // take over for a running worker. Otherwise the
@@ -1538,16 +1534,15 @@ fn start_executing_work<B: ExtraBackendMethods>(
                 while running_with_own_token < tokens.len()
                     && let Some((item, _)) = work_items.pop()
                 {
-                    spawn_work(&cgcx, &mut llvm_start_time, item);
+                    spawn_work(&cgcx, coordinator_send.clone(), &mut llvm_start_time, item);
                     running_with_own_token += 1;
                 }
             }
 
             // Relinquish accidentally acquired extra tokens.
             tokens.truncate(running_with_own_token);
 
-            let msg = coordinator_receive.recv().unwrap();
-            match *msg.downcast::<Message<B>>().ok().unwrap() {
+            match coordinator_receive.recv().unwrap() {
                 // Save the token locally and the next turn of the loop will use
                 // this to spawn a new unit of work, or it may get dropped
                 // immediately if we have no more work to spawn.
@@ -1769,6 +1764,7 @@ pub(crate) struct WorkerFatalError;
 
 fn spawn_work<'a, B: ExtraBackendMethods>(
     cgcx: &'a CodegenContext<B>,
+    coordinator_send: Sender<Message<B>>,
     llvm_start_time: &mut Option<VerboseTimingGuard<'a>>,
     work: WorkItem<B>,
 ) {
@@ -1782,7 +1778,7 @@ fn spawn_work<'a, B: ExtraBackendMethods>(
         // Set up a destructor which will fire off a message that we're done as
         // we exit.
         struct Bomb<B: ExtraBackendMethods> {
-            coordinator_send: Sender<Box<dyn Any + Send>>,
+            coordinator_send: Sender<Message<B>>,
             result: Option<Result<WorkItemResult<B>, FatalError>>,
         }
         impl<B: ExtraBackendMethods> Drop for Bomb<B> {
@@ -1794,11 +1790,11 @@ fn spawn_work<'a, B: ExtraBackendMethods>(
                     }
                     None => Message::WorkItem::<B> { result: Err(None) },
                 };
-                drop(self.coordinator_send.send(Box::new(msg)));
+                drop(self.coordinator_send.send(msg));
             }
         }
 
-        let mut bomb = Bomb::<B> { coordinator_send: cgcx.coordinator_send.clone(), result: None };
+        let mut bomb = Bomb::<B> { coordinator_send, result: None };
 
         // Execute the work itself, and if it finishes successfully then flag
         // ourselves as a success as well.
@@ -2003,7 +1999,7 @@ impl SharedEmitterMain {
 }
 
 pub struct Coordinator<B: ExtraBackendMethods> {
-    pub sender: Sender<Box<dyn Any + Send>>,
+    sender: Sender<Message<B>>,
     future: Option<thread::JoinHandle<Result<CompiledModules, ()>>>,
     // Only used for the Message type.
     phantom: PhantomData<B>,
@@ -2020,7 +2016,7 @@ impl<B: ExtraBackendMethods> Drop for Coordinator<B> {
         if let Some(future) = self.future.take() {
             // If we haven't joined yet, signal to the coordinator that it should spawn no more
             // work, and wait for worker threads to finish.
-            drop(self.sender.send(Box::new(Message::CodegenAborted::<B>)));
+            drop(self.sender.send(Message::CodegenAborted::<B>));
             drop(future.join());
         }
     }
@@ -2079,7 +2075,7 @@ impl<B: ExtraBackendMethods> OngoingCodegen<B> {
     pub(crate) fn codegen_finished(&self, tcx: TyCtxt<'_>) {
         self.wait_for_signal_to_codegen_item();
         self.check_for_errors(tcx.sess);
-        drop(self.coordinator.sender.send(Box::new(Message::CodegenComplete::<B>)));
+        drop(self.coordinator.sender.send(Message::CodegenComplete::<B>));
     }
 
     pub(crate) fn check_for_errors(&self, sess: &Session) {
@@ -2100,28 +2096,25 @@ impl<B: ExtraBackendMethods> OngoingCodegen<B> {
 }
 
 pub(crate) fn submit_codegened_module_to_llvm<B: ExtraBackendMethods>(
-    _backend: &B,
-    tx_to_llvm_workers: &Sender<Box<dyn Any + Send>>,
+    coordinator: &Coordinator<B>,
     module: ModuleCodegen<B::Module>,
     cost: u64,
 ) {
     let llvm_work_item = WorkItem::Optimize(module);
-    drop(tx_to_llvm_workers.send(Box::new(Message::CodegenDone::<B> { llvm_work_item, cost })));
+    drop(coordinator.sender.send(Message::CodegenDone::<B> { llvm_work_item, cost }));
 }
 
 pub(crate) fn submit_post_lto_module_to_llvm<B: ExtraBackendMethods>(
-    _backend: &B,
-    tx_to_llvm_workers: &Sender<Box<dyn Any + Send>>,
+    coordinator: &Coordinator<B>,
     module: CachedModuleCodegen,
 ) {
     let llvm_work_item = WorkItem::CopyPostLtoArtifacts(module);
-    drop(tx_to_llvm_workers.send(Box::new(Message::CodegenDone::<B> { llvm_work_item, cost: 0 })));
+    drop(coordinator.sender.send(Message::CodegenDone::<B> { llvm_work_item, cost: 0 }));
 }
 
 pub(crate) fn submit_pre_lto_module_to_llvm<B: ExtraBackendMethods>(
-    _backend: &B,
     tcx: TyCtxt<'_>,
-    tx_to_llvm_workers: &Sender<Box<dyn Any + Send>>,
+    coordinator: &Coordinator<B>,
     module: CachedModuleCodegen,
 ) {
     let filename = pre_lto_bitcode_filename(&module.name);
@@ -2135,10 +2128,10 @@ pub(crate) fn submit_pre_lto_module_to_llvm<B: ExtraBackendMethods>(
         })
     };
     // Schedule the module to be loaded
-    drop(tx_to_llvm_workers.send(Box::new(Message::AddImportOnlyModule::<B> {
+    drop(coordinator.sender.send(Message::AddImportOnlyModule::<B> {
         module_data: SerializedModule::FromUncompressedFile(mmap),
         work_product: module.source,
-    })));
+    }));
 }
 
 fn pre_lto_bitcode_filename(module_name: &str) -> String {

compiler/rustc_codegen_ssa/src/base.rs

@@ -702,8 +702,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
         // These modules are generally cheap and won't throw off scheduling.
         let cost = 0;
         submit_codegened_module_to_llvm(
-            &backend,
-            &ongoing_codegen.coordinator.sender,
+            &ongoing_codegen.coordinator,
             ModuleCodegen::new_allocator(llmod_id, module_llvm),
             cost,
         );
@@ -800,18 +799,12 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
                 // compilation hang on post-monomorphization errors.
                 tcx.dcx().abort_if_errors();
 
-                submit_codegened_module_to_llvm(
-                    &backend,
-                    &ongoing_codegen.coordinator.sender,
-                    module,
-                    cost,
-                );
+                submit_codegened_module_to_llvm(&ongoing_codegen.coordinator, module, cost);
             }
             CguReuse::PreLto => {
                 submit_pre_lto_module_to_llvm(
-                    &backend,
                     tcx,
-                    &ongoing_codegen.coordinator.sender,
+                    &ongoing_codegen.coordinator,
                     CachedModuleCodegen {
                         name: cgu.name().to_string(),
                         source: cgu.previous_work_product(tcx),
@@ -820,8 +813,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
             }
             CguReuse::PostLto => {
                 submit_post_lto_module_to_llvm(
-                    &backend,
-                    &ongoing_codegen.coordinator.sender,
+                    &ongoing_codegen.coordinator,
                     CachedModuleCodegen {
                         name: cgu.name().to_string(),
                         source: cgu.previous_work_product(tcx),