[modules] Simplify treatment of empty imports.

There's no reason (anymore) to have empty imports in special_imports.  Remove
them from there and rename special_imports to namespace_imports to be more
precise.

R=adamk@chromium.org
BUG=v8:1569

Review-Url: https://codereview.chromium.org/2368613002
Cr-Commit-Position: refs/heads/master@{#39693}

src/ast/modules.cc

@@ -23,19 +23,14 @@ void ModuleDescriptor::AddImport(
 void ModuleDescriptor::AddStarImport(
     const AstRawString* local_name, const AstRawString* module_request,
     Scanner::Location loc, Zone* zone) {
-  DCHECK_NOT_NULL(local_name);
   Entry* entry = new (zone) Entry(loc);
   entry->local_name = local_name;
   entry->module_request = AddModuleRequest(module_request);
-  AddSpecialImport(entry, zone);
+  AddNamespaceImport(entry, zone);
 }
 
-
-void ModuleDescriptor::AddEmptyImport(
-    const AstRawString* module_request, Scanner::Location loc, Zone* zone) {
-  Entry* entry = new (zone) Entry(loc);
-  entry->module_request = AddModuleRequest(module_request);
-  AddSpecialImport(entry, zone);
+void ModuleDescriptor::AddEmptyImport(const AstRawString* module_request) {
+  AddModuleRequest(module_request);
 }
 
 

src/ast/modules.h

@@ -21,7 +21,7 @@ class ModuleDescriptor : public ZoneObject {
   explicit ModuleDescriptor(Zone* zone)
       : module_requests_(zone),
         special_exports_(1, zone),
-        special_imports_(1, zone),
+        namespace_imports_(1, zone),
         regular_exports_(zone),
         regular_imports_(zone) {}
 
@@ -44,9 +44,7 @@ class ModuleDescriptor : public ZoneObject {
   // import "foo.js";
   // import {} from "foo.js";
   // export {} from "foo.js";  (sic!)
-  void AddEmptyImport(
-      const AstRawString* module_request, const Scanner::Location loc,
-      Zone* zone);
+  void AddEmptyImport(const AstRawString* module_request);
 
   // export {x};
   // export {x as y};
@@ -106,9 +104,9 @@ class ModuleDescriptor : public ZoneObject {
     return module_requests_;
   }
 
-  // Empty imports and namespace imports.
-  const ZoneList<const Entry*>& special_imports() const {
-    return special_imports_;
+  // Namespace imports.
+  const ZoneList<const Entry*>& namespace_imports() const {
+    return namespace_imports_;
   }
 
   // All the remaining imports, indexed by local name.
@@ -151,10 +149,12 @@ class ModuleDescriptor : public ZoneObject {
     // case we will report an error when declaring the variable.
   }
 
-  void AddSpecialImport(const Entry* entry, Zone* zone) {
+  void AddNamespaceImport(const Entry* entry, Zone* zone) {
+    DCHECK_NULL(entry->import_name);
     DCHECK_NULL(entry->export_name);
+    DCHECK_NOT_NULL(entry->local_name);
     DCHECK_LE(0, entry->module_request);
-    special_imports_.Add(entry, zone);
+    namespace_imports_.Add(entry, zone);
   }
 
   Handle<FixedArray> SerializeRegularExports(Isolate* isolate,
@@ -166,7 +166,7 @@ class ModuleDescriptor : public ZoneObject {
   // TODO(neis): Use STL datastructure instead of ZoneList?
   ZoneMap<const AstRawString*, int> module_requests_;
   ZoneList<const Entry*> special_exports_;
-  ZoneList<const Entry*> special_imports_;
+  ZoneList<const Entry*> namespace_imports_;
   ZoneMultimap<const AstRawString*, Entry*> regular_exports_;
   ZoneMap<const AstRawString*, const Entry*> regular_imports_;
 

src/ast/scopeinfo.cc

@@ -871,13 +871,13 @@ Handle<ModuleInfo> ModuleInfo::New(Isolate* isolate, Zone* zone,
     }
   }
 
-  // Serialize special imports.
-  Handle<FixedArray> special_imports =
-      isolate->factory()->NewFixedArray(descr->special_imports().length());
+  // Serialize namespace imports.
+  Handle<FixedArray> namespace_imports =
+      isolate->factory()->NewFixedArray(descr->namespace_imports().length());
   {
     int i = 0;
-    for (auto entry : descr->special_imports()) {
-      special_imports->set(i++, *entry->Serialize(isolate));
+    for (auto entry : descr->namespace_imports()) {
+      namespace_imports->set(i++, *entry->Serialize(isolate));
     }
   }
 
@@ -899,7 +899,7 @@ Handle<ModuleInfo> ModuleInfo::New(Isolate* isolate, Zone* zone,
   result->set(kModuleRequestsIndex, *module_requests);
   result->set(kSpecialExportsIndex, *special_exports);
   result->set(kRegularExportsIndex, *regular_exports);
-  result->set(kSpecialImportsIndex, *special_imports);
+  result->set(kNamespaceImportsIndex, *namespace_imports);
   result->set(kRegularImportsIndex, *regular_imports);
   return result;
 }

src/ast/scopes.cc

@@ -185,12 +185,13 @@ ModuleScope::ModuleScope(Isolate* isolate, Handle<ScopeInfo> scope_info,
   module_descriptor_->DeserializeRegularExports(isolate, avfactory,
                                                 regular_exports);
 
-  // Deserialize special imports.
-  Handle<FixedArray> special_imports(module_info->special_imports(), isolate);
-  for (int i = 0, n = special_imports->length(); i < n; ++i) {
+  // Deserialize namespace imports.
+  Handle<FixedArray> namespace_imports(module_info->namespace_imports(),
+                                       isolate);
+  for (int i = 0, n = namespace_imports->length(); i < n; ++i) {
     Handle<ModuleInfoEntry> serialized_entry(
-        ModuleInfoEntry::cast(special_imports->get(i)), isolate);
-    module_descriptor_->AddSpecialImport(
+        ModuleInfoEntry::cast(namespace_imports->get(i)), isolate);
+    module_descriptor_->AddNamespaceImport(
         ModuleDescriptor::Entry::Deserialize(isolate, avfactory,
                                              serialized_entry),
         avfactory->zone());

src/objects-inl.h

@@ -7985,8 +7985,8 @@ FixedArray* ModuleInfo::regular_imports() const {
   return FixedArray::cast(get(kRegularImportsIndex));
 }
 
-FixedArray* ModuleInfo::special_imports() const {
-  return FixedArray::cast(get(kSpecialImportsIndex));
+FixedArray* ModuleInfo::namespace_imports() const {
+  return FixedArray::cast(get(kNamespaceImportsIndex));
 }
 
 #ifdef DEBUG
@@ -7994,7 +7994,7 @@ bool ModuleInfo::Equals(ModuleInfo* other) const {
   return regular_exports() == other->regular_exports() &&
          regular_imports() == other->regular_imports() &&
          special_exports() == other->special_exports() &&
-         special_imports() == other->special_imports();
+         namespace_imports() == other->namespace_imports();
 }
 #endif
 

src/objects.h

@@ -4587,7 +4587,7 @@ class ModuleInfo : public FixedArray {
   inline FixedArray* module_requests() const;
   inline FixedArray* special_exports() const;
   inline FixedArray* regular_exports() const;
-  inline FixedArray* special_imports() const;
+  inline FixedArray* namespace_imports() const;
   inline FixedArray* regular_imports() const;
 
 #ifdef DEBUG
@@ -4600,7 +4600,7 @@ class ModuleInfo : public FixedArray {
     kModuleRequestsIndex,
     kSpecialExportsIndex,
     kRegularExportsIndex,
-    kSpecialImportsIndex,
+    kNamespaceImportsIndex,
     kRegularImportsIndex,
     kLength
   };

src/parsing/parser.cc

@@ -1208,7 +1208,7 @@ void Parser::ParseImportDeclaration(bool* ok) {
   if (tok == Token::STRING) {
     const AstRawString* module_specifier = ParseModuleSpecifier(CHECK_OK_VOID);
     ExpectSemicolon(CHECK_OK_VOID);
-    module()->AddEmptyImport(module_specifier, scanner()->location(), zone());
+    module()->AddEmptyImport(module_specifier);
     return;
   }
 
@@ -1276,7 +1276,7 @@ void Parser::ParseImportDeclaration(bool* ok) {
 
   if (named_imports != nullptr) {
     if (named_imports->length() == 0) {
-      module()->AddEmptyImport(module_specifier, scanner()->location(), zone());
+      module()->AddEmptyImport(module_specifier);
     } else {
       for (int i = 0; i < named_imports->length(); ++i) {
         const NamedImport* import = named_imports->at(i);
@@ -1415,8 +1415,7 @@ Statement* Parser::ParseExportDeclaration(bool* ok) {
                               export_locations[i], zone());
         }
       } else if (length == 0) {
-        module()->AddEmptyImport(module_specifier, scanner()->location(),
-                                 zone());
+        module()->AddEmptyImport(module_specifier);
       } else {
         for (int i = 0; i < length; ++i) {
           module()->AddExport(original_names[i], export_names[i],

test/cctest/test-parsing.cc

@@ -6169,10 +6169,10 @@ TEST(ModuleParsingInternals) {
     CheckEntry(entry, "y", "x", nullptr, -1);
   }
 
-  CHECK_EQ(3, descriptor->special_imports().length());
-  CheckEntry(descriptor->special_imports().at(0), nullptr, nullptr, nullptr, 3);
-  CheckEntry(descriptor->special_imports().at(1), nullptr, "loo", nullptr, 4);
-  CheckEntry(descriptor->special_imports().at(2), nullptr, "foob", nullptr, 4);
+  CHECK_EQ(2, descriptor->namespace_imports().length());
+  CheckEntry(descriptor->namespace_imports().at(0), nullptr, "loo", nullptr, 4);
+  CheckEntry(descriptor->namespace_imports().at(1), nullptr, "foob", nullptr,
+             4);
 
   CHECK_EQ(4, descriptor->regular_imports().size());
   entry = descriptor->regular_imports().find(