Reland "[wasm] Add feature counter for threads and shared memory"

This is a reland of b10a967f

Original change's description:
> [wasm] Add feature counter for threads and shared memory
> 
> This adds a feature counter for WASM shared memory (i.e. the presence
> of the "shared" bit in a WASM module's memory section) and the usage
> of WASM threads opcodes (i.e. wake/wait and atomics).
> 
> This CL also plumbs the WasmFeatures through the compilation pipeline
> to detect features as functions are being compiled.
> 
> R=ahaas@chromium.org, ulan@chromium.org
> BUG=chromium:868844
> 
> Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
> Change-Id: I854f932d3adb16e4fd87196fe2a193950295b856
> Reviewed-on: https://chromium-review.googlesource.com/1186329
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Ben Titzer <titzer@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#55337}

Bug: chromium:868844
Change-Id: Iac3a38d80fa71aadd7147704669a8fd671ecfae8
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/1186343
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55363}

src/compiler/wasm-compiler.cc

@@ -5031,7 +5031,8 @@ TurbofanWasmCompilationUnit::TurbofanWasmCompilationUnit(
 TurbofanWasmCompilationUnit::~TurbofanWasmCompilationUnit() = default;
 
 SourcePositionTable* TurbofanWasmCompilationUnit::BuildGraphForWasmFunction(
-    double* decode_ms, MachineGraph* mcgraph, NodeOriginTable* node_origins) {
+    wasm::WasmFeatures* detected, double* decode_ms, MachineGraph* mcgraph,
+    NodeOriginTable* node_origins) {
   base::ElapsedTimer decode_timer;
   if (FLAG_trace_wasm_decode_time) {
     decode_timer.Start();
@@ -5042,14 +5043,10 @@ SourcePositionTable* TurbofanWasmCompilationUnit::BuildGraphForWasmFunction(
       new (mcgraph->zone()) SourcePositionTable(mcgraph->graph());
   WasmGraphBuilder builder(wasm_unit_->env_, mcgraph->zone(), mcgraph,
                            wasm_unit_->func_body_.sig, source_position_table);
-  // TODO(titzer): gather detected features into a per-module location
-  // in order to increment an embedder feature use count.
-  wasm::WasmFeatures unused_detected_features;
   graph_construction_result_ = wasm::BuildTFGraph(
       wasm_unit_->wasm_engine_->allocator(),
       wasm_unit_->native_module_->enabled_features(), wasm_unit_->env_->module,
-      &builder, &unused_detected_features, wasm_unit_->func_body_,
-      node_origins);
+      &builder, detected, wasm_unit_->func_body_, node_origins);
   if (graph_construction_result_.failed()) {
     if (FLAG_trace_wasm_compiler) {
       StdoutStream{} << "Compilation failed: "
@@ -5102,7 +5099,8 @@ Vector<const char> GetDebugName(Zone* zone, wasm::WasmName name, int index) {
 
 }  // namespace
 
-void TurbofanWasmCompilationUnit::ExecuteCompilation() {
+void TurbofanWasmCompilationUnit::ExecuteCompilation(
+    wasm::WasmFeatures* detected) {
   TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.wasm"),
                "ExecuteTurbofanCompilation");
   double decode_ms = 0;
@@ -5134,7 +5132,7 @@ void TurbofanWasmCompilationUnit::ExecuteCompilation() {
                                               NodeOriginTable(mcgraph->graph())
                                         : nullptr;
     SourcePositionTable* source_positions =
-        BuildGraphForWasmFunction(&decode_ms, mcgraph, node_origins);
+        BuildGraphForWasmFunction(detected, &decode_ms, mcgraph, node_origins);
 
     if (graph_construction_result_.failed()) {
       ok_ = false;

src/compiler/wasm-compiler.h

@@ -40,6 +40,7 @@ struct DecodeStruct;
 typedef compiler::Node TFNode;
 typedef compiler::MachineGraph TFGraph;
 class WasmCode;
+struct WasmFeatures;
 }  // namespace wasm
 
 namespace compiler {
@@ -49,11 +50,12 @@ class TurbofanWasmCompilationUnit {
   explicit TurbofanWasmCompilationUnit(wasm::WasmCompilationUnit* wasm_unit);
   ~TurbofanWasmCompilationUnit();
 
-  SourcePositionTable* BuildGraphForWasmFunction(double* decode_ms,
+  SourcePositionTable* BuildGraphForWasmFunction(wasm::WasmFeatures* detected,
+                                                 double* decode_ms,
                                                  MachineGraph* mcgraph,
                                                  NodeOriginTable* node_origins);
 
-  void ExecuteCompilation();
+  void ExecuteCompilation(wasm::WasmFeatures* detected);
 
   wasm::WasmCode* FinishCompilation(wasm::ErrorThrower*);
 

src/wasm/baseline/liftoff-compiler.cc

@@ -1835,7 +1835,7 @@ class LiftoffCompiler {
 
 }  // namespace
 
-bool LiftoffCompilationUnit::ExecuteCompilation() {
+bool LiftoffCompilationUnit::ExecuteCompilation(WasmFeatures* detected) {
   TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.wasm"),
                "ExecuteLiftoffCompilation");
   base::ElapsedTimer compile_timer;
@@ -1850,11 +1850,9 @@ bool LiftoffCompilationUnit::ExecuteCompilation() {
       compiler::GetWasmCallDescriptor(&zone, wasm_unit_->func_body_.sig);
   base::Optional<TimedHistogramScope> liftoff_compile_time_scope(
       base::in_place, wasm_unit_->counters_->liftoff_compile_time());
-  WasmFeatures unused_detected_features;
   WasmFullDecoder<Decoder::kValidate, LiftoffCompiler> decoder(
-      &zone, module, wasm_unit_->native_module_->enabled_features(),
-      &unused_detected_features, wasm_unit_->func_body_, call_descriptor,
-      wasm_unit_->env_, &zone);
+      &zone, module, wasm_unit_->native_module_->enabled_features(), detected,
+      wasm_unit_->func_body_, call_descriptor, wasm_unit_->env_, &zone);
   decoder.Decode();
   liftoff_compile_time_scope.reset();
   LiftoffCompiler* compiler = &decoder.interface();

src/wasm/baseline/liftoff-compiler.h

@@ -11,6 +11,7 @@ namespace v8 {
 namespace internal {
 namespace wasm {
 
+struct WasmFeatures;
 class ErrorThrower;
 class WasmCode;
 class WasmCompilationUnit;
@@ -20,7 +21,7 @@ class LiftoffCompilationUnit final {
   explicit LiftoffCompilationUnit(WasmCompilationUnit* wasm_unit)
       : wasm_unit_(wasm_unit) {}
 
-  bool ExecuteCompilation();
+  bool ExecuteCompilation(WasmFeatures* detected);
   WasmCode* FinishCompilation(ErrorThrower*);
 
  private:

src/wasm/function-compiler.cc

@@ -73,7 +73,7 @@ WasmCompilationUnit::WasmCompilationUnit(WasmEngine* wasm_engine,
 // {TurbofanWasmCompilationUnit} can be opaque in the header file.
 WasmCompilationUnit::~WasmCompilationUnit() {}
 
-void WasmCompilationUnit::ExecuteCompilation() {
+void WasmCompilationUnit::ExecuteCompilation(WasmFeatures* detected) {
   auto size_histogram = SELECT_WASM_COUNTER(counters_, env_->module->origin,
                                             wasm, function_size_bytes);
   size_histogram->AddSample(
@@ -89,12 +89,12 @@ void WasmCompilationUnit::ExecuteCompilation() {
 
   switch (mode_) {
     case ExecutionTier::kBaseline:
-      if (liftoff_unit_->ExecuteCompilation()) break;
+      if (liftoff_unit_->ExecuteCompilation(detected)) break;
       // Otherwise, fall back to turbofan.
       SwitchMode(ExecutionTier::kOptimized);
       V8_FALLTHROUGH;
     case ExecutionTier::kOptimized:
-      turbofan_unit_->ExecuteCompilation();
+      turbofan_unit_->ExecuteCompilation(detected);
       break;
     case ExecutionTier::kInterpreter:
       UNREACHABLE();  // TODO(titzer): compile interpreter entry stub.
@@ -145,8 +145,9 @@ void WasmCompilationUnit::SwitchMode(ExecutionTier new_mode) {
 
 // static
 WasmCode* WasmCompilationUnit::CompileWasmFunction(
-    NativeModule* native_module, ErrorThrower* thrower, Isolate* isolate,
-    ModuleEnv* env, const WasmFunction* function, ExecutionTier mode) {
+    Isolate* isolate, NativeModule* native_module, WasmFeatures* detected,
+    ErrorThrower* thrower, ModuleEnv* env, const WasmFunction* function,
+    ExecutionTier mode) {
   ModuleWireBytes wire_bytes(native_module->wire_bytes());
   FunctionBody function_body{function->sig, function->code.offset(),
                              wire_bytes.start() + function->code.offset(),
@@ -156,7 +157,7 @@ WasmCode* WasmCompilationUnit::CompileWasmFunction(
                            function_body,
                            wire_bytes.GetNameOrNull(function, env->module),
                            function->func_index, isolate->counters(), mode);
-  unit.ExecuteCompilation();
+  unit.ExecuteCompilation(detected);
   return unit.FinishCompilation(thrower);
 }
 

src/wasm/function-compiler.h

@@ -91,12 +91,12 @@ class WasmCompilationUnit final {
 
   ~WasmCompilationUnit();
 
-  void ExecuteCompilation();
+  void ExecuteCompilation(WasmFeatures* detected);
   WasmCode* FinishCompilation(ErrorThrower* thrower);
 
   static WasmCode* CompileWasmFunction(
-      NativeModule* native_module, ErrorThrower* thrower, Isolate* isolate,
-      ModuleEnv* env, const WasmFunction* function,
+      Isolate* isolate, NativeModule* native_module, WasmFeatures* detected,
+      ErrorThrower* thrower, ModuleEnv* env, const WasmFunction* function,
       ExecutionTier = GetDefaultExecutionTier());
 
   NativeModule* native_module() const { return native_module_; }

src/wasm/module-compiler.cc

@@ -90,7 +90,8 @@ class CompilationState {
   void ScheduleUnitForFinishing(std::unique_ptr<WasmCompilationUnit> unit,
                                 ExecutionTier mode);
 
-  void OnBackgroundTaskStopped();
+  void OnBackgroundTaskStopped(const WasmFeatures& detected);
+  void PublishDetectedFeatures(Isolate* isolate, const WasmFeatures& detected);
   void RestartBackgroundTasks(size_t max = std::numeric_limits<size_t>::max());
   // Only one foreground thread (finisher) is allowed to run at a time.
   // {SetFinisherIsRunning} returns whether the flag changed its state.
@@ -113,6 +114,7 @@ class CompilationState {
   WasmEngine* wasm_engine() const { return wasm_engine_; }
   CompileMode compile_mode() const { return compile_mode_; }
   ModuleEnv* module_env() { return &module_env_; }
+  WasmFeatures* detected_features() { return &detected_features_; }
 
  private:
   void NotifyOnEvent(CompilationEvent event, ErrorThrower* thrower);
@@ -148,6 +150,10 @@ class CompilationState {
   std::vector<std::unique_ptr<WasmCompilationUnit>> baseline_finish_units_;
   std::vector<std::unique_ptr<WasmCompilationUnit>> tiering_finish_units_;
 
+  // Features detected to be used in this module. Features can be detected
+  // as a module is being compiled.
+  WasmFeatures detected_features_ = kNoWasmFeatures;
+
   // End of fields protected by {mutex_}.
   //////////////////////////////////////////////////////////////////////////////
 
@@ -166,6 +172,12 @@ class CompilationState {
 
 namespace {
 
+void UpdateFeatureUseCounts(Isolate* isolate, const WasmFeatures& detected) {
+  if (detected.threads) {
+    isolate->CountUsage(v8::Isolate::UseCounterFeature::kWasmThreadOpcodes);
+  }
+}
+
 class JSToWasmWrapperCache {
  public:
   Handle<Code> GetOrCompileJSToWasmWrapper(Isolate* isolate,
@@ -359,7 +371,8 @@ WasmCode* LazyCompileFunction(Isolate* isolate, NativeModule* native_module,
   ErrorThrower thrower(isolate, "WasmLazyCompile");
   WasmCompilationUnit unit(isolate->wasm_engine(), module_env, native_module,
                            body, func_name, func_index, isolate->counters());
-  unit.ExecuteCompilation();
+  unit.ExecuteCompilation(
+      native_module->compilation_state()->detected_features());
   WasmCode* wasm_code = unit.FinishCompilation(&thrower);
 
   if (WasmCode::ShouldBeLogged(isolate)) wasm_code->LogCode(isolate);
@@ -500,7 +513,8 @@ class CompilationUnitBuilder {
 // foreground and background threads). The no_finisher_callback is called
 // within the result_mutex_ lock when no finishing task is running, i.e. when
 // the finisher_is_running_ flag is not set.
-bool FetchAndExecuteCompilationUnit(CompilationState* compilation_state) {
+bool FetchAndExecuteCompilationUnit(CompilationState* compilation_state,
+                                    WasmFeatures* detected) {
   DisallowHeapAccess no_heap_access;
 
   std::unique_ptr<WasmCompilationUnit> unit =
@@ -513,7 +527,7 @@ bool FetchAndExecuteCompilationUnit(CompilationState* compilation_state) {
   // later as soon as Liftoff can compile any function. Then, we can directly
   // access {unit->mode()} within {ScheduleUnitForFinishing()}.
   ExecutionTier mode = unit->mode();
-  unit->ExecuteCompilation();
+  unit->ExecuteCompilation(detected);
   compilation_state->ScheduleUnitForFinishing(std::move(unit), mode);
 
   return true;
@@ -614,7 +628,9 @@ void CompileInParallel(Isolate* isolate, NativeModule* native_module,
   //      result is enqueued in {baseline_finish_units_}.
   //      The foreground task bypasses waiting on memory threshold, because
   //      its results will immediately be converted to code (below).
-  while (FetchAndExecuteCompilationUnit(compilation_state) &&
+  WasmFeatures detected_features;
+  while (
+      FetchAndExecuteCompilationUnit(compilation_state, &detected_features) &&
       !compilation_state->baseline_compilation_finished()) {
     // 2.b) If {baseline_finish_units_} contains a compilation unit, the main
     //      thread dequeues it and finishes the compilation unit. Compilation
@@ -636,6 +652,9 @@ void CompileInParallel(Isolate* isolate, NativeModule* native_module,
     if (compilation_state->baseline_compilation_finished()) break;
   }
 
+  // Publish features from the foreground and background tasks.
+  compilation_state->PublishDetectedFeatures(isolate, detected_features);
+
   // 4) If tiering-compilation is enabled, we need to set the finisher
   //    to false, such that the background threads will spawn a foreground
   //    thread to finish the top-tier compilation units.
@@ -652,13 +671,14 @@ void CompileSequentially(Isolate* isolate, NativeModule* native_module,
 
   ModuleWireBytes wire_bytes(native_module->wire_bytes());
   const WasmModule* module = module_env->module;
+  WasmFeatures detected = kNoWasmFeatures;
   for (uint32_t i = 0; i < module->functions.size(); ++i) {
     const WasmFunction& func = module->functions[i];
     if (func.imported) continue;  // Imports are compiled at instantiation time.
 
     // Compile the function.
     WasmCode* code = WasmCompilationUnit::CompileWasmFunction(
-        native_module, thrower, isolate, module_env, &func);
+        isolate, native_module, &detected, thrower, module_env, &func);
     if (code == nullptr) {
       TruncatedUserString<> name(wire_bytes.GetName(&func, module));
       thrower->CompileError("Compilation of #%d:%.*s failed.", i, name.length(),
@@ -666,6 +686,7 @@ void CompileSequentially(Isolate* isolate, NativeModule* native_module,
       break;
     }
   }
+  UpdateFeatureUseCounts(isolate, detected);
 }
 
 void ValidateSequentially(Isolate* isolate, NativeModule* native_module,
@@ -831,15 +852,17 @@ class BackgroundCompileTask : public CancelableTask {
     // The number of currently running background tasks is reduced in
     // {OnBackgroundTaskStopped}.
     while (!compilation_state_->failed()) {
-      if (!FetchAndExecuteCompilationUnit(compilation_state_)) {
+      if (!FetchAndExecuteCompilationUnit(compilation_state_,
+                                          &detected_features_)) {
         break;
       }
     }
-    compilation_state_->OnBackgroundTaskStopped();
+    compilation_state_->OnBackgroundTaskStopped(detected_features_);
   }
 
  private:
   CompilationState* compilation_state_;
+  WasmFeatures detected_features_ = kNoWasmFeatures;
 };
 }  // namespace
 
@@ -851,6 +874,12 @@ MaybeHandle<WasmModuleObject> CompileToModuleObject(
   const WasmModule* wasm_module = module.get();
   TimedHistogramScope wasm_compile_module_time_scope(SELECT_WASM_COUNTER(
       isolate->counters(), wasm_module->origin, wasm_compile, module_time));
+
+  // Embedder usage count for declared shared memories.
+  if (wasm_module->has_shared_memory) {
+    isolate->CountUsage(v8::Isolate::UseCounterFeature::kWasmSharedMemory);
+  }
+
   // TODO(6792): No longer needed once WebAssembly code is off heap. Use
   // base::Optional to be able to close the scope before notifying the debugger.
   base::Optional<CodeSpaceMemoryModificationScope> modification_scope(
@@ -2191,6 +2220,11 @@ void AsyncCompileJob::FinishCompile() {
   // Log the code within the generated module for profiling.
   native_module_->LogWasmCodes(isolate_);
 
+  // We can only update the feature counts once the entire compile is done.
+  auto compilation_state = native_module_->compilation_state();
+  compilation_state->PublishDetectedFeatures(
+      isolate_, *compilation_state->detected_features());
+
   // TODO(wasm): compiling wrappers should be made async as well.
   DoSync<CompileWrappers>();
 }
@@ -2376,6 +2410,12 @@ class AsyncCompileJob::PrepareAndStartCompile : public CompileStep {
     // is done.
     job_->background_task_manager_.CancelAndWait();
 
+    // Embedder usage count for declared shared memories.
+    if (job_->module_->has_shared_memory) {
+      job_->isolate_->CountUsage(
+          v8::Isolate::UseCounterFeature::kWasmSharedMemory);
+    }
+
     // Create heap objects for script and module bytes to be stored in the
     // module object. Asm.js is not compiled asynchronously.
     Handle<Script> script = CreateWasmScript(job_->isolate_, job_->wire_bytes_);
@@ -2876,10 +2916,21 @@ void CompilationState::ScheduleUnitForFinishing(
   }
 }
 
-void CompilationState::OnBackgroundTaskStopped() {
+void CompilationState::OnBackgroundTaskStopped(const WasmFeatures& detected) {
   base::LockGuard<base::Mutex> guard(&mutex_);
   DCHECK_LE(1, num_background_tasks_);
   --num_background_tasks_;
+  UnionFeaturesInto(&detected_features_, detected);
+}
+
+void CompilationState::PublishDetectedFeatures(Isolate* isolate,
+                                               const WasmFeatures& detected) {
+  // Notifying the isolate of the feature counts must take place under
+  // the mutex, because even if we have finished baseline compilation,
+  // tiering compilations may still occur in the background.
+  base::LockGuard<base::Mutex> guard(&mutex_);
+  UnionFeaturesInto(&detected_features_, detected);
+  UpdateFeatureUseCounts(isolate, detected_features_);
 }
 
 void CompilationState::RestartBackgroundTasks(size_t max) {

src/wasm/wasm-engine.cc

@@ -171,8 +171,10 @@ std::shared_ptr<StreamingDecoder> WasmEngine::StartStreamingCompilation(
 bool WasmEngine::CompileFunction(Isolate* isolate, NativeModule* native_module,
                                  uint32_t function_index, ExecutionTier tier) {
   ErrorThrower thrower(isolate, "Manually requested tier up");
+  // Note we assume that "one-off" compilations can discard detected features.
+  WasmFeatures detected = kNoWasmFeatures;
   WasmCode* ret = WasmCompilationUnit::CompileWasmFunction(
-      native_module, &thrower, isolate,
+      isolate, native_module, &detected, &thrower,
       GetModuleEnv(native_module->compilation_state()),
       &native_module->module()->functions[function_index], tier);
   return ret != nullptr;

src/wasm/wasm-features.cc

@@ -13,11 +13,11 @@ namespace wasm {
 
 #define COMMA ,
 #define SPACE
-#define DO_UNION(feat, desc, val) dst->feat |= src->feat;
+#define DO_UNION(feat, desc, val) dst->feat |= src.feat;
 #define FLAG_REF(feat, desc, val) FLAG_experimental_wasm_##feat
 
-void UnionFeaturesInto(WasmFeatures* dst, WasmFeatures* src) {
-  FOREACH_WASM_FEATURE(DO_UNION, SPACE)
+void UnionFeaturesInto(WasmFeatures* dst, const WasmFeatures& src) {
+  FOREACH_WASM_FEATURE(DO_UNION, SPACE);
 }
 
 WasmFeatures WasmFeaturesFromFlags() {

src/wasm/wasm-features.h

@@ -57,7 +57,8 @@ V8_EXPORT_PRIVATE WasmFeatures WasmFeaturesFromFlags();
 // Precondition: A valid context must be set in {isolate->context()}.
 V8_EXPORT_PRIVATE WasmFeatures WasmFeaturesFromIsolate(Isolate* isolate);
 
-V8_EXPORT_PRIVATE void UnionFeaturesInto(WasmFeatures* dst, WasmFeatures* src);
+V8_EXPORT_PRIVATE void UnionFeaturesInto(WasmFeatures* dst,
+                                         const WasmFeatures& src);
 
 }  // namespace wasm
 }  // namespace internal

test/cctest/wasm/test-wasm-shared-engine.cc

@@ -352,8 +352,9 @@ TEST(SharedEngineRunThreadedTierUp) {
     HandleScope scope(isolate.isolate());
     Handle<WasmInstanceObject> instance = isolate.ImportInstance(module);
     ErrorThrower thrower(isolate.isolate(), "Forced Tier Up");
+    WasmFeatures detected = kNoWasmFeatures;
     WasmCompilationUnit::CompileWasmFunction(
-        module.get(), &thrower, isolate.isolate(),
+        isolate.isolate(), module.get(), &detected, &thrower,
         GetModuleEnv(module->compilation_state()),
         &module->module()->functions[0], ExecutionTier::kOptimized);
     CHECK_EQ(23, isolate.Run(instance));

test/cctest/wasm/wasm-run-utils.cc

@@ -432,7 +432,8 @@ void WasmFunctionCompiler::Build(const byte* start, const byte* end) {
   WasmCompilationUnit unit(isolate()->wasm_engine(), &module_env, native_module,
                            func_body, func_name, function_->func_index,
                            isolate()->counters(), tier);
-  unit.ExecuteCompilation();
+  WasmFeatures unused_detected_features;
+  unit.ExecuteCompilation(&unused_detected_features);
   WasmCode* wasm_code = unit.FinishCompilation(&thrower);
   if (WasmCode::ShouldBeLogged(isolate())) {
     wasm_code->LogCode(isolate());