[modules] Basic support of exports

src/contexts.h

Index: src/contexts.h
diff --git a/src/contexts.h b/src/contexts.h
index 406ae28c7242a3bbabea381261f9f02101cdf5cc..b32725b03f16e857e92a8b0dd2f3ade4f935d9b9 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -227,6 +227,7 @@ enum ContextLookupFlags {
   V(UINT8_ARRAY_FUN_INDEX, JSFunction, uint8_array_fun)                        \
   V(UINT8_CLAMPED_ARRAY_FUN_INDEX, JSFunction, uint8_clamped_array_fun)        \
   V(UINT8X16_FUNCTION_INDEX, JSFunction, uint8x16_function)                    \
+  V(CURRENT_MODULE_INDEX, JSModule, current_module)                                            \
   NATIVE_CONTEXT_INTRINSIC_FUNCTIONS(V)                                        \
   NATIVE_CONTEXT_IMPORTED_FIELDS(V)
 
@@ -310,6 +311,7 @@ class ScriptContextTable : public FixedArray {
 //                block scopes, it may also be a struct being a
 //                SloppyBlockWithEvalContextExtension, pairing the ScopeInfo
 //                with an extension object.
+//                XXX module
 //
 // [ native_context ]  A pointer to the native context.
 //
@@ -387,9 +389,13 @@ class Context: public FixedArray {
   ScopeInfo* scope_info();
   String* catch_name();
 
+  // Find the module context (assuming there is one) and return the associated
+  // module object.
+  JSModule* module();
+
   // Get the context where var declarations will be hoisted to, which
   // may be the context itself.
-  Context* declaration_context();
+  Context* declaration_context();  // XXX should this return a module context?
   bool is_declaration_context();
 
   // Get the next closure's context on the context chain.