Fix use of history timers in background threads.

src/compiler/wasm-compiler.cc

Index: src/compiler/wasm-compiler.cc
diff --git a/src/compiler/wasm-compiler.cc b/src/compiler/wasm-compiler.cc
index 531fef51f8a2bdff8bbcc6ae45746dc328bee6ce..68be6f7b9c3f4ad21ec4a4e88dd62707c89bed72 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -3908,27 +3908,24 @@ Vector<const char> GetDebugName(Zone* zone, wasm::WasmName name, int index) {
 
 WasmCompilationUnit::WasmCompilationUnit(Isolate* isolate,
                                          wasm::ModuleBytesEnv* module_env,
-                                         const wasm::WasmFunction* function,
-                                         bool is_sync)
+                                         const wasm::WasmFunction* function)
     : WasmCompilationUnit(
           isolate, &module_env->module_env,
           wasm::FunctionBody{
               function->sig, module_env->wire_bytes.start(),
               module_env->wire_bytes.start() + function->code_start_offset,
               module_env->wire_bytes.start() + function->code_end_offset},
-          module_env->wire_bytes.GetNameOrNull(function), function->func_index,
-          is_sync) {}
+          module_env->wire_bytes.GetNameOrNull(function),
+          function->func_index) {}
 
 WasmCompilationUnit::WasmCompilationUnit(Isolate* isolate,
                                          wasm::ModuleEnv* module_env,
                                          wasm::FunctionBody body,
-                                         wasm::WasmName name, int index,
-                                         bool is_sync)
+                                         wasm::WasmName name, int index)
     : isolate_(isolate),
       module_env_(module_env),
       func_body_(body),
       func_name_(name),
-      is_sync_(is_sync),
       graph_zone_(new Zone(isolate->allocator(), ZONE_NAME)),
       jsgraph_(new (graph_zone()) JSGraph(
           isolate, new (graph_zone()) Graph(graph_zone()),
@@ -3956,18 +3953,8 @@ void WasmCompilationUnit::InitializeHandles() {
 
 void WasmCompilationUnit::ExecuteCompilation() {
   DCHECK(handles_initialized_);
-  if (is_sync_) {
-    // TODO(karlschimpf): Make this work when asynchronous.
-    // https://bugs.chromium.org/p/v8/issues/detail?id=6361
-    HistogramTimerScope wasm_compile_function_time_scope(
-        isolate_->counters()->wasm_compile_function_time());
-    ExecuteCompilationInternal();
-    return;
-  }
-  ExecuteCompilationInternal();
-}
-
-void WasmCompilationUnit::ExecuteCompilationInternal() {
+  HistogramTimerScope wasm_compile_function_time_scope(
+      isolate_->counters()->wasm_compile_function_time());

[jochen (gone - plz use gerrit), 2017/06/12 09:18:34]

no isolate_ deref on background threads

[kschimpf, 2017/06/12 16:47:04]

It turns out that this step is not run in the background. Hence, this is safe.

   if (FLAG_trace_wasm_compiler) {
     if (func_name_.start() != nullptr) {
       PrintF("Compiling wasm function %d:'%.*s'\n\n", func_index(),
@@ -4006,11 +3993,8 @@ void WasmCompilationUnit::ExecuteCompilationInternal() {
       !module_env_->module->is_wasm()));
   ok_ = job_->ExecuteJob() == CompilationJob::SUCCEEDED;
   // TODO(bradnelson): Improve histogram handling of size_t.
-  if (is_sync_)
-    // TODO(karlschimpf): Make this work when asynchronous.
-    // https://bugs.chromium.org/p/v8/issues/detail?id=6361
-    isolate_->counters()->wasm_compile_function_peak_memory_bytes()->AddSample(
-        static_cast<int>(jsgraph_->graph()->zone()->allocation_size()));
+  isolate_->counters()->wasm_compile_function_peak_memory_bytes()->AddSample(
+      static_cast<int>(jsgraph_->graph()->zone()->allocation_size()));
 
   if (FLAG_trace_wasm_decode_time) {
     double pipeline_ms = pipeline_timer.Elapsed().InMillisecondsF();