[maglev] Allow waiting for compile jobs to finish

Add a mechanism similar to the optimizing compile dispatcher, for tests
to be able to wait for Maglev compilation to finish, and to force
finalization.

Bug: v8:7700
Change-Id: I0ef542001fe9f6622b1231eb9406130ad81c8f6e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3865551
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jakob Linke <jgruber@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82899}

src/maglev/maglev-concurrent-dispatcher.cc

@@ -192,6 +192,15 @@ void MaglevConcurrentDispatcher::FinalizeFinishedJobs() {
   }
 }
 
+void MaglevConcurrentDispatcher::AwaitCompileJobs() {
+  // Use Join to wait until there are no more queued or running jobs.
+  job_handle_->Join();
+  // Join kills the job handle, so drop it and post a new one.
+  job_handle_ = V8::GetCurrentPlatform()->PostJob(
+      TaskPriority::kUserVisible, std::make_unique<JobTask>(this));
+  DCHECK(incoming_queue_.IsEmpty());
+}
+
 }  // namespace maglev
 }  // namespace internal
 }  // namespace v8

src/maglev/maglev-concurrent-dispatcher.h

@@ -87,6 +87,8 @@ class MaglevConcurrentDispatcher final {
   // Called from the main thread.
   void FinalizeFinishedJobs();
 
+  void AwaitCompileJobs();
+
   bool is_enabled() const { return static_cast<bool>(job_handle_); }
 
  private:

src/runtime/runtime-test.cc

@@ -23,6 +23,9 @@
 #include "src/heap/heap-inl.h"  // For ToBoolean. TODO(jkummerow): Drop.
 #include "src/heap/heap-write-barrier-inl.h"
 #include "src/ic/stub-cache.h"
+#ifdef V8_ENABLE_MAGLEV
+#include "src/maglev/maglev-concurrent-dispatcher.h"
+#endif  // V8_ENABLE_MAGLEV
 #include "src/objects/js-atomics-synchronization-inl.h"
 #include "src/objects/js-function-inl.h"
 #include "src/objects/js-regexp-inl.h"
@@ -594,6 +597,13 @@ void FinalizeOptimization(Isolate* isolate) {
   isolate->optimizing_compile_dispatcher()->AwaitCompileTasks();
   isolate->optimizing_compile_dispatcher()->InstallOptimizedFunctions();
   isolate->optimizing_compile_dispatcher()->set_finalize(true);
+
+#if V8_ENABLE_MAGLEV
+  if (isolate->maglev_concurrent_dispatcher()->is_enabled()) {
+    isolate->maglev_concurrent_dispatcher()->AwaitCompileJobs();
+    isolate->maglev_concurrent_dispatcher()->FinalizeFinishedJobs();
+  }
+#endif  // V8_ENABLE_MAGLEV
 }
 
 BytecodeOffset OffsetOfNextJumpLoop(Isolate* isolate, UnoptimizedFrame* frame) {
@@ -879,6 +889,11 @@ RUNTIME_FUNCTION(Runtime_WaitForBackgroundOptimization) {
   DCHECK_EQ(0, args.length());
   if (isolate->concurrent_recompilation_enabled()) {
     isolate->optimizing_compile_dispatcher()->AwaitCompileTasks();
+#if V8_ENABLE_MAGLEV
+    if (isolate->maglev_concurrent_dispatcher()->is_enabled()) {
+      isolate->maglev_concurrent_dispatcher()->AwaitCompileJobs();
+    }
+#endif  // V8_ENABLE_MAGLEV
   }
   return ReadOnlyRoots(isolate).undefined_value();
 }