Revert "[maglev] Finish & enable basic Maglev concurrent tierups"

This reverts commit 406bcd69.

Reason for revert: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux64/46797/overview

Original change's description:
> [maglev] Finish & enable basic Maglev concurrent tierups
>
> This implements the last bits of basic concurrent Maglev compilation.
> When jobs have been processed, schedule an interrupt to trigger codegen
> and building the Code object on the main thread.
>
> Bug: v8:7700
> Change-Id: I348ade4777ddddf7c3a6b0575d9f51e5fa00c9fb
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3528494
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#79516}

Bug: v8:7700
Change-Id: I1faa092b96e56149b4db2e271680f39c7af61554
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3532231
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79517}

src/execution/stack-guard.cc

@@ -10,7 +10,6 @@
 #include "src/execution/isolate.h"
 #include "src/execution/simulator.h"
 #include "src/logging/counters.h"
-#include "src/maglev/maglev-concurrent-dispatcher.h"
 #include "src/objects/backing-store.h"
 #include "src/roots/roots-inl.h"
 #include "src/tracing/trace-event.h"
@@ -326,14 +325,6 @@ Object StackGuard::HandleInterrupts() {
     isolate_->baseline_batch_compiler()->InstallBatch();
   }
 
-#ifdef V8_ENABLE_MAGLEV
-  if (TestAndClear(&interrupt_flags, INSTALL_MAGLEV_CODE)) {
-    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"),
-                 "V8.FinalizeMaglevConcurrentCompilation");
-    isolate_->maglev_concurrent_dispatcher()->FinalizeFinishedJobs();
-  }
-#endif  // V8_ENABLE_MAGLEV
-
   if (TestAndClear(&interrupt_flags, API_INTERRUPT)) {
     TRACE_EVENT0("v8.execute", "V8.InvokeApiInterruptCallbacks");
     // Callbacks must be invoked outside of ExecutionAccess lock.

src/execution/stack-guard.h

@@ -54,8 +54,7 @@ class V8_EXPORT_PRIVATE V8_NODISCARD StackGuard final {
   V(DEOPT_MARKED_ALLOCATION_SITES, DeoptMarkedAllocationSites, 5) \
   V(GROW_SHARED_MEMORY, GrowSharedMemory, 6)                      \
   V(LOG_WASM_CODE, LogWasmCode, 7)                                \
-  V(WASM_CODE_GC, WasmCodeGC, 8)                                  \
-  V(INSTALL_MAGLEV_CODE, InstallMaglevCode, 9)
+  V(WASM_CODE_GC, WasmCodeGC, 8)
 
 #define V(NAME, Name, id)                                    \
   inline bool Check##Name() { return CheckInterrupt(NAME); } \

src/execution/tiering-manager.cc

@@ -59,8 +59,9 @@ class OptimizationDecision {
  public:
   static constexpr OptimizationDecision Maglev() {
     // TODO(v8:7700): Consider using another reason here.
+    // TODO(v8:7700): Support concurrency.
     return {OptimizationReason::kHotAndStable, CodeKind::MAGLEV,
-            ConcurrencyMode::kConcurrent};
+            ConcurrencyMode::kNotConcurrent};
   }
   static constexpr OptimizationDecision TurbofanHotAndStable() {
     return {OptimizationReason::kHotAndStable, CodeKind::TURBOFAN,

src/maglev/maglev-compilation-info.h

@@ -63,6 +63,9 @@ class MaglevCompilationInfo final {
   void set_graph(Graph* graph) { graph_ = graph; }
   Graph* graph() const { return graph_; }
 
+  void set_codet(MaybeHandle<CodeT> codet) { codet_ = codet; }
+  MaybeHandle<CodeT> codet() const { return codet_; }
+
   // Flag accessors (for thread-safe access to global flags).
   // TODO(v8:7700): Consider caching these.
 #define V(Name) \
@@ -100,6 +103,9 @@ class MaglevCompilationInfo final {
   // Produced off-thread during ExecuteJobImpl.
   Graph* graph_ = nullptr;
 
+  // Produced during FinalizeJobImpl.
+  MaybeHandle<CodeT> codet_;
+
 #define V(Name) const bool Name##_;
   MAGLEV_COMPILATION_FLAG_LIST(V)
 #undef V

src/maglev/maglev-concurrent-dispatcher.cc

@@ -106,12 +106,9 @@ CompilationJob::Status MaglevCompilationJob::ExecuteJobImpl(
 }
 
 CompilationJob::Status MaglevCompilationJob::FinalizeJobImpl(Isolate* isolate) {
-  Handle<CodeT> codet;
-  if (!maglev::MaglevCompiler::GenerateCode(info()->toplevel_compilation_unit())
-           .ToHandle(&codet)) {
-    return CompilationJob::FAILED;
-  }
-  info()->function()->set_code(*codet);
+  info()->set_codet(maglev::MaglevCompiler::GenerateCode(
+      info()->toplevel_compilation_unit()));
+  // TODO(v8:7700): Actual return codes.
   return CompilationJob::SUCCEEDED;
 }
 
@@ -135,7 +132,8 @@ class MaglevConcurrentDispatcher::JobTask final : public v8::JobTask {
       CHECK_EQ(status, CompilationJob::SUCCEEDED);
       outgoing_queue()->Enqueue(std::move(job));
     }
-    isolate()->stack_guard()->RequestInstallMaglevCode();
+    // TODO(v8:7700):
+    // isolate_->stack_guard()->RequestInstallMaglevCode();
   }
 
   size_t GetMaxConcurrency(size_t) const override {
@@ -180,7 +178,6 @@ void MaglevConcurrentDispatcher::EnqueueJob(
 }
 
 void MaglevConcurrentDispatcher::FinalizeFinishedJobs() {
-  HandleScope handle_scope(isolate_);
   while (!outgoing_queue_.IsEmpty()) {
     std::unique_ptr<MaglevCompilationJob> job;
     outgoing_queue_.Dequeue(&job);

src/maglev/maglev-concurrent-dispatcher.h

@@ -21,13 +21,6 @@ namespace maglev {
 
 class MaglevCompilationInfo;
 
-// TODO(v8:7700): While basic infrastructure now exists, there are many TODOs
-// that should still be addressed soon:
-// - Full tracing support through --trace-opt.
-// - Concurrent codegen.
-// - Concurrent Code object creation (optional?).
-// - Test support for concurrency (see %FinalizeOptimization).
-
 // Exports needed functionality without exposing implementation details.
 class ExportedMaglevCompilationInfo final {
  public: