[modules] Implement namespace imports.

src/objects.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 #include <memory>
 
@@ skipping 53 matching lines @@
 //           - JSWeakMap
 //           - JSWeakSet
 //         - JSRegExp
 //         - JSFunction
 //         - JSGeneratorObject
 //         - JSGlobalObject
 //         - JSGlobalProxy
 //         - JSValue
 //           - JSDate
 //         - JSMessageObject
+//         - JSModuleNamespace
 //       - JSProxy
 //     - FixedArrayBase
 //       - ByteArray
 //       - BytecodeArray
 //       - FixedArray
 //         - DescriptorArray
 //         - FrameArray
 //         - LiteralsArray
 //         - HashTable
 //           - Dictionary
@@ skipping 325 matching lines @@
   V(TRANSITION_ARRAY_TYPE)                                      \
                                                                 \
   V(JS_MESSAGE_OBJECT_TYPE)                                     \
                                                                 \
   V(JS_VALUE_TYPE)                                              \
   V(JS_DATE_TYPE)                                               \
   V(JS_OBJECT_TYPE)                                             \
   V(JS_ARGUMENTS_TYPE)                                          \
   V(JS_CONTEXT_EXTENSION_OBJECT_TYPE)                           \
   V(JS_GENERATOR_OBJECT_TYPE)                                   \
+  V(JS_MODULE_NAMESPACE_TYPE)                                   \
   V(JS_GLOBAL_OBJECT_TYPE)                                      \
   V(JS_GLOBAL_PROXY_TYPE)                                       \
   V(JS_API_OBJECT_TYPE)                                         \
   V(JS_SPECIAL_API_OBJECT_TYPE)                                 \
   V(JS_ARRAY_TYPE)                                              \
   V(JS_ARRAY_BUFFER_TYPE)                                       \
   V(JS_TYPED_ARRAY_TYPE)                                        \
   V(JS_DATA_VIEW_TYPE)                                          \
   V(JS_PROXY_TYPE)                                              \
   V(JS_SET_TYPE)                                                \
@@ skipping 281 matching lines @@
   JS_SPECIAL_API_OBJECT_TYPE,  // LAST_SPECIAL_RECEIVER_TYPE
   JS_VALUE_TYPE,               // LAST_CUSTOM_ELEMENTS_RECEIVER
   JS_MESSAGE_OBJECT_TYPE,
   JS_DATE_TYPE,
   // Like JS_OBJECT_TYPE, but created from API function.
   JS_API_OBJECT_TYPE,
   JS_OBJECT_TYPE,
   JS_ARGUMENTS_TYPE,
   JS_CONTEXT_EXTENSION_OBJECT_TYPE,
   JS_GENERATOR_OBJECT_TYPE,
+  JS_MODULE_NAMESPACE_TYPE,
   JS_ARRAY_TYPE,
   JS_ARRAY_BUFFER_TYPE,
   JS_TYPED_ARRAY_TYPE,
   JS_DATA_VIEW_TYPE,
   JS_SET_TYPE,
   JS_MAP_TYPE,
   JS_SET_ITERATOR_TYPE,
   JS_MAP_ITERATOR_TYPE,
   JS_WEAK_MAP_TYPE,
   JS_WEAK_SET_TYPE,
@@ skipping 149 matching lines @@
 class ConsString;
 class ElementsAccessor;
 class FixedArrayBase;
 class FunctionLiteral;
 class JSGlobalObject;
 class KeyAccumulator;
 class LayoutDescriptor;
 class LiteralsArray;
 class LookupIterator;
 class FieldType;
+class Module;
 class ModuleDescriptor;
 class ModuleInfoEntry;
 class ModuleInfo;
 class ObjectHashTable;
 class ObjectVisitor;
 class PropertyCell;
 class PropertyDescriptor;
 class SafepointEntry;
 class SharedFunctionInfo;
 class StringStream;
@@ skipping 64 matching lines @@
   V(FixedFloat32Array)           \
   V(FixedFloat64Array)           \
   V(FixedUint8ClampedArray)      \
   V(ByteArray)                   \
   V(BytecodeArray)               \
   V(FreeSpace)                   \
   V(JSReceiver)                  \
   V(JSObject)                    \
   V(JSContextExtensionObject)    \
   V(JSGeneratorObject)           \
+  V(JSModuleNamespace)           \
   V(Map)                         \
   V(DescriptorArray)             \
   V(FrameArray)                  \
   V(TransitionArray)             \
   V(LiteralsArray)               \
   V(TypeFeedbackMetadata)        \
   V(TypeFeedbackVector)          \
   V(DeoptimizationInputData)     \
   V(DeoptimizationOutputData)    \
   V(DependentCode)               \
@@ skipping 2960 matching lines @@
   MUST_USE_RESULT static inline Handle<ObjectHashTable> Shrink(
       Handle<ObjectHashTable> table,
       Handle<Object> key);
 
   // Looks up the value associated with the given key. The hole value is
   // returned in case the key is not present.
   Object* Lookup(Handle<Object> key);
   Object* Lookup(Handle<Object> key, int32_t hash);
   Object* Lookup(Isolate* isolate, Handle<Object> key, int32_t hash);
 
+  // Returns the value at entry.
+  Object* ValueAt(int entry);
+
   // Adds (or overwrites) the value associated with the given key.
   static Handle<ObjectHashTable> Put(Handle<ObjectHashTable> table,
                                      Handle<Object> key,
                                      Handle<Object> value);
   static Handle<ObjectHashTable> Put(Handle<ObjectHashTable> table,
                                      Handle<Object> key, Handle<Object> value,
                                      int32_t hash);
 
   // Returns an ObjectHashTable (possibly |table|) where |key| has been removed.
   static Handle<ObjectHashTable> Remove(Handle<ObjectHashTable> table,
@@ skipping 3928 matching lines @@
   static const int kInputOrDebugPosOffset = kReceiverOffset + kPointerSize;
   static const int kResumeModeOffset = kInputOrDebugPosOffset + kPointerSize;
   static const int kContinuationOffset = kResumeModeOffset + kPointerSize;
   static const int kOperandStackOffset = kContinuationOffset + kPointerSize;
   static const int kSize = kOperandStackOffset + kPointerSize;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(JSGeneratorObject);
 };
 
+// When importing a module namespace (import * as foo from "bar"), a
+// JSModuleNamespace object (representing module "bar") is created and bound to
+// the declared variable (foo).  A module can have at most one namespace object.
+class JSModuleNamespace : public JSObject {
+ public:
+  DECLARE_CAST(JSModuleNamespace)
+  DECLARE_VERIFIER(JSModuleNamespace)
+
+  // The actual module whose namespace is being represented.
+  DECL_ACCESSORS(module, Module)
+
+  // Retrieve the value exported by [module] under the given [name]. If there is
+  // no such export, return Just(undefined). If the export is uninitialized,
+  // schedule an exception and return Nothing.
+  MUST_USE_RESULT MaybeHandle<Object> GetExport(Handle<String> name);
+
+  static const int kModuleOffset = JSObject::kHeaderSize;
+  static const int kSize = kModuleOffset + kPointerSize;
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(JSModuleNamespace);
+};
+
 // A Module object is a mapping from export names to cells
 // This is still very much in flux.
 class Module : public Struct {
  public:
   DECLARE_CAST(Module)
   DECLARE_VERIFIER(Module)
   DECLARE_PRINTER(Module)
 
-  // The code representing this Module, either a
-  // SharedFunctionInfo or a JSFunction depending
-  // on whether it's been instantiated.
+  // The code representing this Module, either a SharedFunctionInfo or a
+  // JSFunction depending on whether it's been instantiated.
   DECL_ACCESSORS(code, Object)
 
   DECL_ACCESSORS(exports, ObjectHashTable)
 
+  // The namespace object (or undefined).
+  DECL_ACCESSORS(module_namespace, HeapObject)
+
   // [[RequestedModules]]: Modules imported or re-exported by this module.
   // Corresponds 1-to-1 to the module specifier strings in
   // ModuleInfo::module_requests.
   DECL_ACCESSORS(requested_modules, FixedArray)
 
   // [[Evaluated]]: Whether this module has been evaluated. Modules
   // are only evaluated a single time.
   DECL_BOOLEAN_ACCESSORS(evaluated)
 
-  // Storage for [[Evaluated]]
+  // Storage for [[Evaluated]].
   DECL_INT_ACCESSORS(flags)
 
   // Embedder-specified data
   DECL_ACCESSORS(embedder_data, Object)
 
   // Get the SharedFunctionInfo associated with the code.
   inline SharedFunctionInfo* shared() const;
 
   // Get the ModuleInfo associated with the code.
   inline ModuleInfo* info() const;
@@ skipping 12 matching lines @@
   // Implementation of spec operation ModuleEvaluation.
   static MUST_USE_RESULT MaybeHandle<Object> Evaluate(Handle<Module> module);
 
   static Handle<Object> LoadExport(Handle<Module> module, Handle<String> name);
   static void StoreExport(Handle<Module> module, Handle<String> name,
                           Handle<Object> value);
 
   static Handle<Object> LoadImport(Handle<Module> module, Handle<String> name,
                                    int module_request);
 
+  // Get the namespace object for [module_request] of [module].  If it doesn't
+  // exist yet, it is created.
+  static Handle<JSModuleNamespace> GetModuleNamespace(Handle<Module> module,
+                                                      int module_request);
+
   static const int kCodeOffset = HeapObject::kHeaderSize;
   static const int kExportsOffset = kCodeOffset + kPointerSize;
   static const int kRequestedModulesOffset = kExportsOffset + kPointerSize;
   static const int kFlagsOffset = kRequestedModulesOffset + kPointerSize;
   static const int kEmbedderDataOffset = kFlagsOffset + kPointerSize;
-  static const int kSize = kEmbedderDataOffset + kPointerSize;
+  static const int kModuleNamespaceOffset = kEmbedderDataOffset + kPointerSize;
+  static const int kSize = kModuleNamespaceOffset + kPointerSize;
 
  private:
   enum { kEvaluatedBit };
 
   static void CreateExport(Handle<Module> module, Handle<FixedArray> names);
   static void CreateIndirectExport(Handle<Module> module, Handle<String> name,
                                    Handle<ModuleInfoEntry> entry);
 
+  // Get the namespace object for [module].  If it doesn't exist yet, it is
+  // created.
+  static Handle<JSModuleNamespace> GetModuleNamespace(Handle<Module> module);
+
   // The [must_resolve] argument indicates whether or not an exception should be
   // thrown in case the module does not provide an export named [name]
   // (including when a cycle is detected).  An exception is always thrown in the
   // case of conflicting star exports.
   //
   // If [must_resolve] is true, a null result indicates an exception. If
   // [must_resolve] is false, a null result may or may not indicate an
   // exception (so check manually!).
   class ResolveSet;
   static MUST_USE_RESULT MaybeHandle<Cell> ResolveExport(
@@ skipping 3447 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_