[modules] Assign cell indices at validation time.

src/debug/debug-scopes.cc

 // 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.
 
 #include "src/debug/debug-scopes.h"
 
 #include <memory>
 
 #include "src/ast/scopes.h"
 #include "src/debug/debug.h"
@@ skipping 783 matching lines @@
           ->value();
   for (int i = 0; i < module_variable_count; ++i) {
     Handle<String> local_name;
     bool is_export;
     {
       String* name;
       int index;
       scope_info->ModuleVariable(i, &name, &index);
       CHECK(!ScopeInfo::VariableIsSynthetic(name));
       local_name = handle(name, isolate);
-      is_export = index == Variable::kModuleExportIndex;
+      DCHECK_NE(index, 0);
+      is_export = index > 0;

[adamk, 2016/10/31 18:25:04]

Comparisons like these getting added in various places also worry me. Perhaps
there's some way to encapsulate more of this logic? Not sure if that would be in
ModuleDescriptor or Variable. But It seems really fragile to have to have all
these magic zeros and >, < operators around (too easy to get one wrong and have
it slip through review).

[neis, 2016/11/03 10:43:48]

It's already in Variable (IsExport), but here we don't have a Variable. 
Fortunately, this one will go away in a followup change that replaces LoadImport
and LoadExport with a single LoadVariable.

     }
 
     Handle<Object> value;
     if (is_export) {
       value =
           Module::LoadExport(handle(context->module(), isolate), local_name);
     } else {
       Handle<ModuleInfo> module_info(scope_info->ModuleDescriptorInfo(),
                                      isolate);
       Handle<ModuleInfoEntry> entry =
           ModuleInfo::LookupRegularImport(module_info, local_name);
       Handle<String> import_name(String::cast(entry->import_name()), isolate);
-      int module_request = Smi::cast(entry->module_request())->value();
       value = Module::LoadImport(handle(context->module(), isolate),
-                                 import_name, module_request);
+                                 import_name, entry->module_request());
     }
 
     // Reflect variables under TDZ as undefined in scope object.
     if (value->IsTheHole(isolate)) continue;
     // This should always succeed.
     // TODO(verwaest): Use AddDataProperty instead.
     JSObject::SetOwnPropertyIgnoreAttributes(scope_object, local_name, value,
                                              NONE)
         .Check();
   }
@@ skipping 41 matching lines @@
     DCHECK((beg_pos >= 0 && end_pos >= 0) || inner_scope->is_hidden());
     if (beg_pos <= position && position < end_pos) {
       GetNestedScopeChain(isolate, inner_scope, position);
       return;
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8