[modules] Various minor cleanups.

Bug: 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I0ecc0af1668f5036bb591e8236d9a28fba61cea5
Reviewed-on: https://chromium-review.googlesource.com/881782
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50861}

include/v8.h

@@ -1136,6 +1136,7 @@ class V8_EXPORT Module {
  public:
   /**
    * The different states a module can be in.
+   *
    * This corresponds to the states used in ECMAScript except that "evaluated"
    * is split into kEvaluated and kErrored, indicating success and failure,
    * respectively.
@@ -1186,7 +1187,7 @@ class V8_EXPORT Module {
                                                 Local<Module> referrer);
 
   /**
-   * ModuleDeclarationInstantiation
+   * Instantiates the module and its dependencies.
    *
    * Returns an empty Maybe<bool> if an exception occurred during
    * instantiation. (In the case where the callback throws an exception, that
@@ -1196,16 +1197,19 @@ class V8_EXPORT Module {
                                                       ResolveCallback callback);
 
   /**
-   * ModuleEvaluation
+   * Evaluates the module and its dependencies.
    *
-   * Returns the completion value.
-   * TODO(neis): Be more precise or say nothing.
+   * If status is kInstantiated, run the module's code. On success, set status
+   * to kEvaluated and return the completion value; on failure, set status to
+   * kErrored and propagate the thrown exception (which is then also available
+   * via |GetException|).
    */
   V8_WARN_UNUSED_RESULT MaybeLocal<Value> Evaluate(Local<Context> context);
 
   /**
    * Returns the namespace object of this module.
-   * The module's status must be kEvaluated.
+   *
+   * The module's status must be at least kInstantiated.
    */
   Local<Value> GetModuleNamespace();
 };

src/objects-debug.cc

@@ -1296,7 +1296,7 @@ void Module::ModuleVerify() {
 
   CHECK((status() >= kEvaluating && code()->IsModuleInfo()) ||
         (status() == kInstantiated && code()->IsJSGeneratorObject()) ||
-        (status() >= kInstantiating && code()->IsJSFunction()) ||
+        (status() == kInstantiating && code()->IsJSFunction()) ||
         (code()->IsSharedFunctionInfo()));
 
   CHECK_EQ(status() == kErrored, !exception()->IsTheHole(GetIsolate()));

src/objects/module.h

@@ -24,17 +24,16 @@ class ModuleInfoEntry;
 class String;
 class Zone;
 
-// A Module object is a mapping from export names to cells
-// This is still very much in flux.
+// The runtime representation of an ECMAScript module.
 class Module : public Struct {
  public:
   DECL_CAST(Module)
   DECL_VERIFIER(Module)
   DECL_PRINTER(Module)
 
-  // The code representing this Module, or an abstraction thereof.
-  // This is either a SharedFunctionInfo or a JSFunction or a ModuleInfo
-  // depending on whether the module has been instantiated and evaluated.  See
+  // The code representing this module, or an abstraction thereof.
+  // This is either a SharedFunctionInfo, a JSFunction, a JSGeneratorObject, or
+  // a ModuleInfo, depending on the state (status) the module is in. See
   // Module::ModuleVerify() for the precise invariant.
   DECL_ACCESSORS(code, Object)