Revert of [modules] Store Module metadata in per-Context EmbedderData

src/d8.cc

Index: src/d8.cc
diff --git a/src/d8.cc b/src/d8.cc
index 32e6636ecb0d9d423e39a15a935e4b4bfb09f258..920a6f488f203a9a871fd0db0b364677187dbace 100644
--- a/src/d8.cc
+++ b/src/d8.cc
@@ -9,7 +9,7 @@
 
 #include <algorithm>
 #include <fstream>
-#include <unordered_map>
+#include <map>
 #include <utility>
 #include <vector>
 
@@ -572,74 +572,29 @@
   return result;
 }
 
-// Per-context Module data, allowing sharing of module maps
-// across top-level module loads.
-class ModuleEmbedderData {
- private:
-  class ModuleGlobalHash {
-   public:
-    explicit ModuleGlobalHash(Isolate* isolate) : isolate_(isolate) {}
-    size_t operator()(const Global<Module>& module) const {
-      return module.Get(isolate_)->GetIdentityHash();
-    }
-
-   private:
-    Isolate* isolate_;
-  };
-
- public:
-  explicit ModuleEmbedderData(Isolate* isolate)
-      : module_to_directory_map(10, ModuleGlobalHash(isolate)) {}
-
-  // Map from normalized module specifier to Module.
-  std::unordered_map<std::string, Global<Module>> specifier_to_module_map;
-  // Map from Module to the directory that Module was loaded from.
-  std::unordered_map<Global<Module>, std::string, ModuleGlobalHash>
-      module_to_directory_map;
-};
-
-enum {
-  // The debugger reserves the first slot in the Context embedder data.
-  kDebugIdIndex = Context::kDebugIdIndex,
-  kModuleEmbedderDataIndex
-};
-
-void InitializeModuleEmbedderData(Local<Context> context) {
-  context->SetAlignedPointerInEmbedderData(
-      kModuleEmbedderDataIndex, new ModuleEmbedderData(context->GetIsolate()));
-}
-
-ModuleEmbedderData* GetModuleDataFromContext(Local<Context> context) {
-  return static_cast<ModuleEmbedderData*>(
-      context->GetAlignedPointerFromEmbedderData(kModuleEmbedderDataIndex));
-}
-
-void DisposeModuleEmbedderData(Local<Context> context) {
-  delete GetModuleDataFromContext(context);
-  context->SetAlignedPointerInEmbedderData(kModuleEmbedderDataIndex, nullptr);
-}
-
 MaybeLocal<Module> ResolveModuleCallback(Local<Context> context,
                                          Local<String> specifier,
-                                         Local<Module> referrer) {
+                                         Local<Module> referrer,
+                                         Local<Value> data) {
   Isolate* isolate = context->GetIsolate();
-  ModuleEmbedderData* d = GetModuleDataFromContext(context);
-  auto dir_name_it =
-      d->module_to_directory_map.find(Global<Module>(isolate, referrer));
-  CHECK(dir_name_it != d->module_to_directory_map.end());
+  auto module_map = static_cast<std::map<std::string, Global<Module>>*>(
+      External::Cast(*data)->Value());
+  Local<String> dir_name = Local<String>::Cast(referrer->GetEmbedderData());
   std::string absolute_path =
-      NormalizePath(ToSTLString(specifier), dir_name_it->second);
-  auto module_it = d->specifier_to_module_map.find(absolute_path);
-  CHECK(module_it != d->specifier_to_module_map.end());
-  return module_it->second.Get(isolate);
+      NormalizePath(ToSTLString(specifier), ToSTLString(dir_name));
+  auto it = module_map->find(absolute_path);
+  if (it != module_map->end()) {
+    return it->second.Get(isolate);
+  }
+  return MaybeLocal<Module>();
 }
 
 }  // anonymous namespace
 
-MaybeLocal<Module> Shell::FetchModuleTree(Local<Context> context,
-                                          const std::string& file_name) {
+MaybeLocal<Module> Shell::FetchModuleTree(
+    Isolate* isolate, const std::string& file_name,
+    std::map<std::string, Global<Module>>* module_map) {
   DCHECK(IsAbsolutePath(file_name));
-  Isolate* isolate = context->GetIsolate();
   TryCatch try_catch(isolate);
   try_catch.SetVerbose(true);
   Local<String> source_text = ReadFile(isolate, file_name.c_str());
@@ -656,22 +611,19 @@
     ReportException(isolate, &try_catch);
     return MaybeLocal<Module>();
   }
-
-  ModuleEmbedderData* d = GetModuleDataFromContext(context);
-  CHECK(d->specifier_to_module_map
-            .insert(std::make_pair(file_name, Global<Module>(isolate, module)))
-            .second);
+  module_map->insert(
+      std::make_pair(file_name, Global<Module>(isolate, module)));
 
   std::string dir_name = DirName(file_name);
-  CHECK(d->module_to_directory_map
-            .insert(std::make_pair(Global<Module>(isolate, module), dir_name))
-            .second);
+  module->SetEmbedderData(
+      String::NewFromUtf8(isolate, dir_name.c_str(), NewStringType::kNormal)
+          .ToLocalChecked());
 
   for (int i = 0, length = module->GetModuleRequestsLength(); i < length; ++i) {
     Local<String> name = module->GetModuleRequest(i);
     std::string absolute_path = NormalizePath(ToSTLString(name), dir_name);
-    if (!d->specifier_to_module_map.count(absolute_path)) {
-      if (FetchModuleTree(context, absolute_path).IsEmpty()) {
+    if (!module_map->count(absolute_path)) {
+      if (FetchModuleTree(isolate, absolute_path, module_map).IsEmpty()) {
         return MaybeLocal<Module>();
       }
     }
@@ -683,14 +635,12 @@
 bool Shell::ExecuteModule(Isolate* isolate, const char* file_name) {
   HandleScope handle_scope(isolate);
 
-  PerIsolateData* data = PerIsolateData::Get(isolate);
-  Local<Context> realm = data->realms_[data->realm_current_].Get(isolate);
-  Context::Scope context_scope(realm);
-
   std::string absolute_path = NormalizePath(file_name, GetWorkingDirectory());
 
   Local<Module> root_module;
-  if (!FetchModuleTree(realm, absolute_path).ToLocal(&root_module)) {
+  std::map<std::string, Global<Module>> module_map;
+  if (!FetchModuleTree(isolate, absolute_path, &module_map)
+           .ToLocal(&root_module)) {
     return false;
   }
 
@@ -698,9 +648,16 @@
   try_catch.SetVerbose(true);
 
   MaybeLocal<Value> maybe_result;
-  if (root_module->Instantiate(realm, ResolveModuleCallback)) {
-    maybe_result = root_module->Evaluate(realm);
-    EmptyMessageQueues(isolate);
+  {
+    PerIsolateData* data = PerIsolateData::Get(isolate);
+    Local<Context> realm = data->realms_[data->realm_current_].Get(isolate);
+    Context::Scope context_scope(realm);
+
+    if (root_module->Instantiate(realm, ResolveModuleCallback,
+                                 External::New(isolate, &module_map))) {
+      maybe_result = root_module->Evaluate(realm);
+      EmptyMessageQueues(isolate);
+    }
   }
   Local<Value> result;
   if (!maybe_result.ToLocal(&result)) {
@@ -830,7 +787,6 @@
     try_catch.ReThrow();
     return MaybeLocal<Context>();
   }
-  InitializeModuleEmbedderData(context);
   data->realms_[index].Reset(isolate, context);
   args.GetReturnValue().Set(index);
   return context;
@@ -864,7 +820,6 @@
     Throw(args.GetIsolate(), "Invalid realm index");
     return;
   }
-  DisposeModuleEmbedderData(data->realms_[index].Get(isolate));
   data->realms_[index].Reset();
   isolate->ContextDisposedNotification();
   isolate->IdleNotificationDeadline(g_platform->MonotonicallyIncreasingTime());
@@ -1533,7 +1488,6 @@
   EscapableHandleScope handle_scope(isolate);
   Local<Context> context = Context::New(isolate, NULL, global_template);
   DCHECK(!context.IsEmpty());
-  InitializeModuleEmbedderData(context);
   Context::Scope scope(context);
 
   i::Factory* factory = reinterpret_cast<i::Isolate*>(isolate)->factory();
@@ -1859,7 +1813,6 @@
           PerIsolateData::RealmScope realm_scope(PerIsolateData::Get(isolate));
           Execute(isolate);
         }
-        DisposeModuleEmbedderData(context);
       }
       Shell::CollectGarbage(isolate);
     }
@@ -2119,7 +2072,6 @@
           }
         }
       }
-      DisposeModuleEmbedderData(context);
     }
     Shell::CollectGarbage(isolate);
   }
@@ -2303,7 +2255,6 @@
       PerIsolateData::RealmScope realm_scope(PerIsolateData::Get(isolate));
       options.isolate_sources[0].Execute(isolate);
     }
-    DisposeModuleEmbedderData(context);
   }
   CollectGarbage(isolate);
   for (int i = 1; i < options.num_isolates; ++i) {