[modules] Assign cell indices at validation time.

src/ast/modules.h

Index: src/ast/modules.h
diff --git a/src/ast/modules.h b/src/ast/modules.h
index dcb5132bd59fa5a1d6eb9ab372429389de6aaef4..ff1ae5a8026b2b6cdc9bb02dd863edb2c85d3fec 100644
--- a/src/ast/modules.h
+++ b/src/ast/modules.h
@@ -82,6 +82,7 @@ class ModuleDescriptor : public ZoneObject {
     // module specifiers and into the Module's array of requested modules.  A
     // negative value means no module request.
     int module_request;
+    int cell_index;

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

Maybe add a comment here too, especially since 0 is a special value?

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

Done.

 
     // TODO(neis): Remove local_name component?
     explicit Entry(Scanner::Location loc)
@@ -89,7 +90,8 @@ class ModuleDescriptor : public ZoneObject {
           export_name(nullptr),
           local_name(nullptr),
           import_name(nullptr),
-          module_request(-1) {}
+          module_request(-1),
+          cell_index(0) {}
 
     // (De-)serialization support.
     // Note that the location value is not preserved as it's only needed by the
@@ -110,7 +112,7 @@ class ModuleDescriptor : public ZoneObject {
   }
 
   // All the remaining imports, indexed by local name.
-  const ZoneMap<const AstRawString*, const Entry*>& regular_imports() const {
+  const ZoneMap<const AstRawString*, Entry*>& regular_imports() const {
     return regular_imports_;
   }
 
@@ -139,7 +141,7 @@ class ModuleDescriptor : public ZoneObject {
     special_exports_.Add(entry, zone);
   }
 
-  void AddRegularImport(const Entry* entry) {
+  void AddRegularImport(Entry* entry) {
     DCHECK_NOT_NULL(entry->import_name);
     DCHECK_NOT_NULL(entry->local_name);
     DCHECK_NULL(entry->export_name);
@@ -168,7 +170,7 @@ class ModuleDescriptor : public ZoneObject {
   ZoneList<const Entry*> special_exports_;
   ZoneList<const Entry*> namespace_imports_;
   ZoneMultimap<const AstRawString*, Entry*> regular_exports_;
-  ZoneMap<const AstRawString*, const Entry*> regular_imports_;
+  ZoneMap<const AstRawString*, Entry*> regular_imports_;
 
   // If there are multiple export entries with the same export name, return the
   // last of them (in source order).  Otherwise return nullptr.
@@ -192,6 +194,8 @@ class ModuleDescriptor : public ZoneObject {
   // (The import entry is never deleted.)
   void MakeIndirectExportsExplicit(Zone* zone);
 
+  void AssignCellIndices();

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

Please give this a comment: how are cell indices assigned?

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

Done.

+
   int AddModuleRequest(const AstRawString* specifier) {
     DCHECK_NOT_NULL(specifier);
     auto it = module_requests_