use a hash table for the function cache as blink is leaking functiontemplates

dcarney · Commit bot · commit d7f25f557c20 · 2015-03-09T12:26:28.000Z
BUG= Review URL: https://codereview.chromium.org/988283003 Cr-Commit-Position: refs/heads/master@{#27066}
diff --git a/src/api-natives.cc b/src/api-natives.cc
@@ -207,36 +207,33 @@ MaybeHandle<JSObject> InstantiateObject(Isolate* isolate,
 }
 
 
-void InstallInCache(Isolate* isolate, int serial_number,
-                    Handle<JSFunction> function) {
+void CacheFunction(Isolate* isolate, Handle<Smi> serial_number,
+                   Handle<JSFunction> function) {
   auto cache = isolate->function_cache();
-  if (cache->length() <= serial_number) {
-    int new_size;
-    if (isolate->next_serial_number() < 50) {
-      new_size = 100;
-    } else {
-      new_size = 3 * isolate->next_serial_number() / 2;
-    }
-    cache = FixedArray::CopySize(cache, new_size);
-    isolate->native_context()->set_function_cache(*cache);
-  }
-  cache->set(serial_number, *function);
+  auto new_cache = ObjectHashTable::Put(cache, serial_number, function);
+  isolate->native_context()->set_function_cache(*new_cache);
+}
+
+
+void UncacheFunction(Isolate* isolate, Handle<Smi> serial_number) {
+  auto cache = isolate->function_cache();
+  bool was_present = false;
+  auto new_cache = ObjectHashTable::Remove(cache, serial_number, &was_present);
+  DCHECK(was_present);
+  isolate->native_context()->set_function_cache(*new_cache);
 }
 
 
 MaybeHandle<JSFunction> InstantiateFunction(Isolate* isolate,
                                             Handle<FunctionTemplateInfo> data,
                                             Handle<Name> name) {
-  int serial_number = Smi::cast(data->serial_number())->value();
+  auto serial_number = handle(Smi::cast(data->serial_number()), isolate);
   // Probe cache.
   if (!data->do_not_cache()) {
     auto cache = isolate->function_cache();
-    // Fast case: see if the function has already been instantiated
-    if (serial_number < cache->length()) {
-      Handle<Object> element = FixedArray::get(cache, serial_number);
-      if (element->IsJSFunction()) {
-        return Handle<JSFunction>::cast(element);
-      }
+    Object* element = cache->Lookup(serial_number);
+    if (element->IsJSFunction()) {
+      return handle(JSFunction::cast(element), isolate);
     }
   }
   // Enter a new scope.  Recursion could otherwise create a lot of handles.
@@ -279,15 +276,14 @@ MaybeHandle<JSFunction> InstantiateFunction(Isolate* isolate,
     function->shared()->set_name(*name);
   }
   if (!data->do_not_cache()) {
-    // Cache the function to limit recursion.
-    InstallInCache(isolate, serial_number, function);
+    // Cache the function.
+    CacheFunction(isolate, serial_number, function);
   }
   auto result = ConfigureInstance(isolate, function, data);
   if (result.is_null()) {
-    // uncache on error.
+    // Uncache on error.
     if (!data->do_not_cache()) {
-      auto cache = isolate->function_cache();
-      cache->set(serial_number, isolate->heap()->undefined_value());
+      UncacheFunction(isolate, serial_number);
     }
     return MaybeHandle<JSFunction>();
   }
diff --git a/src/api-natives.h b/src/api-natives.h
@@ -12,6 +12,8 @@ namespace internal {
 
 class ApiNatives {
  public:
+  static const int kInitialFunctionCacheSize = 256;
+
   MUST_USE_RESULT static MaybeHandle<JSFunction> InstantiateFunction(
       Handle<FunctionTemplateInfo> data);
 
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
@@ -2117,7 +2117,9 @@ bool Genesis::InstallNatives() {
 
   InstallNativeFunctions();
 
-  native_context()->set_function_cache(heap()->empty_fixed_array());
+  auto function_cache =
+      ObjectHashTable::New(isolate(), ApiNatives::kInitialFunctionCacheSize);
+  native_context()->set_function_cache(*function_cache);
 
   // Store the map for the string prototype after the natives has been compiled
   // and the String function has been set up.
diff --git a/src/contexts.h b/src/contexts.h
@@ -140,7 +140,7 @@ enum BindingFlags {
   V(MAKE_MESSAGE_FUN_INDEX, JSFunction, make_message_fun)                      \
   V(GET_STACK_TRACE_LINE_INDEX, JSFunction, get_stack_trace_line_fun)          \
   V(CONFIGURE_GLOBAL_INDEX, JSFunction, configure_global_fun)                  \
-  V(FUNCTION_CACHE_INDEX, FixedArray, function_cache)                          \
+  V(FUNCTION_CACHE_INDEX, ObjectHashTable, function_cache)                     \
   V(JSFUNCTION_RESULT_CACHES_INDEX, FixedArray, jsfunction_result_caches)      \
   V(NORMALIZED_MAP_CACHE_INDEX, Object, normalized_map_cache)                  \
   V(RUNTIME_CONTEXT_INDEX, Context, runtime_context)                           \
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
@@ -20038,15 +20038,15 @@ THREADED_TEST(FunctionNew) {
   env->Global()->Set(v8_str("func"), func);
   Local<Value> result = CompileRun("func();");
   CHECK(v8::Integer::New(isolate, 17)->Equals(result));
-  // Verify function not cached
-  int serial_number =
-      i::Smi::cast(v8::Utils::OpenHandle(*func)
-          ->shared()->get_api_func_data()->serial_number())->value();
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  i::Handle<i::FixedArray> cache(i_isolate->native_context()->function_cache());
-  if (serial_number < cache->length()) {
-    CHECK(cache->get(serial_number)->IsUndefined());
-  }
+  // Verify function not cached
+  auto serial_number = handle(i::Smi::cast(v8::Utils::OpenHandle(*func)
+                                               ->shared()
+                                               ->get_api_func_data()
+                                               ->serial_number()),
+                              i_isolate);
+  auto cache = i_isolate->function_cache();
+  CHECK(cache->Lookup(serial_number)->IsTheHole());
   // Verify that each Function::New creates a new function instance
   Local<Object> data2 = v8::Object::New(isolate);
   function_new_expected_env = data2;
