[modules] Basic support of exports

src/contexts.cc

Index: src/contexts.cc
diff --git a/src/contexts.cc b/src/contexts.cc
index 0822e45cd0ed71e4a878acf92ba84da04f67760d..7db29766c637794000ca438e23a6af8748a294ce 100644
--- a/src/contexts.cc
+++ b/src/contexts.cc
@@ -110,7 +110,7 @@ JSReceiver* Context::extension_receiver() {
 
 
 ScopeInfo* Context::scope_info() {
-  DCHECK(IsModuleContext() || IsScriptContext() || IsBlockContext());
+  DCHECK(IsScriptContext() || IsBlockContext());
   HeapObject* object = extension();
   if (object->IsSloppyBlockWithEvalContextExtension()) {
     DCHECK(IsBlockContext());
@@ -120,6 +120,16 @@ ScopeInfo* Context::scope_info() {
 }
 
 
+JSModule* Context::module() {
+  Context* current = this;
+  while (!current->IsModuleContext()) {
+    current = current->previous();
+    DCHECK_NOT_NULL(current);  // XXX

[adamk, 2016/09/01 23:13:34]

In our offline discussion I said this was a bit bogus because of how objects
work, but I do see that the bootstrapper actually _does_ set this to NULL. That
seems really wrong to me, though, so I'd prefer to leave out this DCHECK, as
it'll start failing if we ever fix the bootstrapper.

[neis, 2016/09/02 11:32:58]

Done.

+  }
+  return JSModule::cast(current->extension());
+}
+
+
 String* Context::catch_name() {
   DCHECK(IsCatchContext());
   return String::cast(extension());
@@ -185,6 +195,7 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
                                int* index, PropertyAttributes* attributes,
                                InitializationFlag* init_flag,
                                VariableMode* variable_mode) {
+  DCHECK(!IsModuleContext());
   Isolate* isolate = GetIsolate();
   Handle<Context> context(this, isolate);