[wasm] Store the semaphore for parallel compilation in exactly one smart pointer.

src/wasm/wasm-module.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/atomic-utils.h"
 #include "src/macro-assembler.h"
 #include "src/objects.h"
 #include "src/property-descriptor.h"
 #include "src/v8.h"
 
@@ skipping 512 matching lines @@
   for (uint32_t i = FLAG_skip_compiling_wasm_funcs; i < functions.size(); i++) {
     compilation_units[i] = new compiler::WasmCompilationUnit(
         &thrower, isolate, &module_env, &functions[i], i);
   }
 }
 
 uint32_t* StartCompilationTasks(
     Isolate* isolate,
     std::vector<compiler::WasmCompilationUnit*>& compilation_units,
     std::queue<compiler::WasmCompilationUnit*>& executed_units,
-    const base::SmartPointer<base::Semaphore>& pending_tasks,
-    base::Mutex& result_mutex, base::AtomicNumber<size_t>& next_unit) {
+    base::Semaphore* pending_tasks, base::Mutex& result_mutex,
+    base::AtomicNumber<size_t>& next_unit) {
   const size_t num_tasks =
       Min(static_cast<size_t>(FLAG_wasm_num_compilation_tasks),
           V8::GetCurrentPlatform()->NumberOfAvailableBackgroundThreads());
   uint32_t* task_ids = new uint32_t[num_tasks];
   for (size_t i = 0; i < num_tasks; i++) {
     WasmCompilationTask* task =
         new WasmCompilationTask(isolate, &compilation_units, &executed_units,
-                                pending_tasks.get(), &result_mutex, &next_unit);
+                                pending_tasks, &result_mutex, &next_unit);
     task_ids[i] = task->id();
     V8::GetCurrentPlatform()->CallOnBackgroundThread(
         task, v8::Platform::kShortRunningTask);
   }
   return task_ids;
 }
 
-void WaitForCompilationTasks(
-    Isolate* isolate, uint32_t* task_ids,
-    const base::SmartPointer<base::Semaphore>& pending_tasks) {
+void WaitForCompilationTasks(Isolate* isolate, uint32_t* task_ids,
+                             base::Semaphore* pending_tasks) {
   const size_t num_tasks =
       Min(static_cast<size_t>(FLAG_wasm_num_compilation_tasks),
           V8::GetCurrentPlatform()->NumberOfAvailableBackgroundThreads());
   for (size_t i = 0; i < num_tasks; i++) {
     // If the task has not started yet, then we abort it. Otherwise we wait for
     // it to finish.
     if (!isolate->cancelable_task_manager()->TryAbort(task_ids[i])) {
       pending_tasks->Wait();
     }
   }
@@ skipping 54 matching lines @@
   // Objects for the synchronization with the background threads.
   base::SmartPointer<base::Semaphore> pending_tasks(new base::Semaphore(0));
   base::Mutex result_mutex;
   base::AtomicNumber<size_t> next_unit(
       static_cast<size_t>(FLAG_skip_compiling_wasm_funcs));
 
   // 2) The main thread spawns {WasmCompilationTask} instances which run on
   //    the background threads.
   base::SmartArrayPointer<uint32_t> task_ids(
       StartCompilationTasks(isolate, compilation_units, executed_units,
-                            pending_tasks, result_mutex, next_unit));
+                            pending_tasks.get(), result_mutex, next_unit));
 
   // 3.a) The background threads and the main thread pick one compilation
   //      unit at a time and execute the parallel phase of the compilation
   //      unit. After finishing the execution of the parallel phase, the
   //      result is enqueued in {executed_units}.
   while (FetchAndExecuteCompilationUnit(isolate, &compilation_units,
                                         &executed_units, &result_mutex,
                                         &next_unit)) {
     // 3.b) If {executed_units} contains a compilation unit, the main thread
     //      dequeues it and finishes the compilation unit. Compilation units
     //      are finished concurrently to the background threads to save
     //      memory.
     FinishCompilationUnits(executed_units, functions, result_mutex);
   }
   // 4) After the parallel phase of all compilation units has started, the
   //    main thread waits for all {WasmCompilationTask} instances to finish.
-  WaitForCompilationTasks(isolate, task_ids.get(), pending_tasks);
+  WaitForCompilationTasks(isolate, task_ids.get(), pending_tasks.get());
   // Finish the compilation of the remaining compilation units.
   FinishCompilationUnits(executed_units, functions, result_mutex);
 }
 
 void CompileSequentially(Isolate* isolate, const WasmModule* module,
                          std::vector<Handle<Code>>& functions,
                          ErrorThrower* thrower, ModuleEnv* module_env) {
   DCHECK(!thrower->error());
 
   for (uint32_t i = FLAG_skip_compiling_wasm_funcs;
@@ skipping 468 matching lines @@
   Object* info = wasm->GetInternalField(kWasmDebugInfo);
   if (!info->IsUndefined(wasm->GetIsolate())) return WasmDebugInfo::cast(info);
   Handle<WasmDebugInfo> new_info = WasmDebugInfo::New(handle(wasm));
   wasm->SetInternalField(kWasmDebugInfo, *new_info);
   return *new_info;
 }
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8