Revert of [modules] Basic support of exports

src/interpreter/bytecode-generator.cc

Index: src/interpreter/bytecode-generator.cc
diff --git a/src/interpreter/bytecode-generator.cc b/src/interpreter/bytecode-generator.cc
index 8822344e192ada7ee16104f1df28f184b9e5d501..e1e87546a9c23cf3ad8d798b07e95590f6f2e041 100644
--- a/src/interpreter/bytecode-generator.cc
+++ b/src/interpreter/bytecode-generator.cc
@@ -743,6 +743,7 @@
     VisitGeneratorPrologue();
   }
 
+  // Build function context only if there are context allocated variables.
   if (scope()->NeedsContext()) {
     // Push a new inner context scope for the function.
     VisitNewLocalFunctionContext();
@@ -939,8 +940,7 @@
       break;
     }
     case VariableLocation::MODULE:
-      // Nothing to do here.
-      break;
+      UNREACHABLE();
   }
 }
 
@@ -979,11 +979,7 @@
       break;
     }
     case VariableLocation::MODULE:
-      DCHECK(variable->mode() == LET);
-      VisitForAccumulatorValue(decl->fun());
-      VisitVariableAssignment(variable, Token::INIT,
-                              FeedbackVectorSlot::Invalid());
-      break;
+      UNREACHABLE();
   }
 }
 
@@ -1982,21 +1978,8 @@
       builder()->LoadLookupSlot(variable->name(), typeof_mode);
       break;
     }
-    case VariableLocation::MODULE: {
-      ModuleDescriptor* descriptor = scope()->GetModuleScope()->module();
-      if (variable->IsExport()) {
-        auto it = descriptor->regular_exports().find(variable->raw_name());
-        DCHECK(it != descriptor->regular_exports().end());
-        Register export_name = register_allocator()->NewRegister();
-        builder()
-            ->LoadLiteral(it->second->export_name->string())
-            .StoreAccumulatorInRegister(export_name)
-            .CallRuntime(Runtime::kLoadModuleExport, export_name, 1);
-      } else {
-        UNIMPLEMENTED();
-      }
-      break;
-    }
+    case VariableLocation::MODULE:
+      UNREACHABLE();
   }
   execution_result()->SetResultInAccumulator();
 }
@@ -2194,33 +2177,8 @@
       builder()->StoreLookupSlot(variable->name(), language_mode());
       break;
     }
-    case VariableLocation::MODULE: {
-      DCHECK(IsDeclaredVariableMode(mode));
-
-      if (mode == CONST && op != Token::INIT) {
-        builder()->CallRuntime(Runtime::kThrowConstAssignError, Register(), 0);
-        break;
-      }
-
-      // If we don't throw above, we know that we're dealing with an
-      // export because imports are const and we do not generate initializing
-      // assignments for them.
-      DCHECK(variable->IsExport());
-
-      ModuleDescriptor* mod = scope()->GetModuleScope()->module();
-      auto it = mod->regular_exports().find(variable->raw_name());
-      DCHECK(it != mod->regular_exports().end());
-
-      register_allocator()->PrepareForConsecutiveAllocations(2);
-      Register export_name = register_allocator()->NextConsecutiveRegister();
-      Register value = register_allocator()->NextConsecutiveRegister();
-      builder()
-          ->StoreAccumulatorInRegister(value)
-          .LoadLiteral(it->second->export_name->string())
-          .StoreAccumulatorInRegister(export_name)
-          .CallRuntime(Runtime::kStoreModuleExport, export_name, 2);
-      break;
-    }
+    case VariableLocation::MODULE:
+      UNREACHABLE();
   }
 }
 
@@ -3177,36 +3135,18 @@
   AccumulatorResultScope accumulator_execution_result(this);
   Scope* scope = this->scope();
 
-  // Create the appropriate context.
+  // Allocate a new local context.
   if (scope->is_script_scope()) {
     RegisterAllocationScope register_scope(this);
-    register_allocator()->PrepareForConsecutiveAllocations(2);
-    Register closure = register_allocator()->NextConsecutiveRegister();
-    Register scope_info = register_allocator()->NextConsecutiveRegister();
+    Register closure = register_allocator()->NewRegister();
+    Register scope_info = register_allocator()->NewRegister();
+    DCHECK(Register::AreContiguous(closure, scope_info));
     builder()
         ->LoadAccumulatorWithRegister(Register::function_closure())
         .StoreAccumulatorInRegister(closure)
         .LoadLiteral(scope->scope_info())
         .StoreAccumulatorInRegister(scope_info)
         .CallRuntime(Runtime::kNewScriptContext, closure, 2);
-  } else if (scope->is_module_scope()) {
-    // We don't need to do anything for the outer script scope.
-    DCHECK(scope->outer_scope()->is_script_scope());
-
-    RegisterAllocationScope register_scope(this);
-    register_allocator()->PrepareForConsecutiveAllocations(3);
-    Register module = register_allocator()->NextConsecutiveRegister();
-    Register closure = register_allocator()->NextConsecutiveRegister();
-    Register scope_info = register_allocator()->NextConsecutiveRegister();
-    // A JSFunction representing a module is called with the module object as
-    // its sole argument, which we pass on to PushModuleContext.
-    builder()
-        ->MoveRegister(builder()->Parameter(1), module)
-        .LoadAccumulatorWithRegister(Register::function_closure())
-        .StoreAccumulatorInRegister(closure)
-        .LoadLiteral(scope->scope_info())
-        .StoreAccumulatorInRegister(scope_info)
-        .CallRuntime(Runtime::kPushModuleContext, module, 3);
   } else {
     int slot_count = scope->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
     builder()->CreateFunctionContext(slot_count);
@@ -3353,7 +3293,8 @@
   AccumulatorResultScope accumulator_execution_result(this);
   DeclarationScope* closure_scope =
       execution_context()->scope()->GetClosureScope();
-  if (closure_scope->is_script_scope()) {
+  if (closure_scope->is_script_scope() ||
+      closure_scope->is_module_scope()) {
     // Contexts nested in the native context have a canonical empty function as
     // their closure, not the anonymous closure containing the global code.
     Register native_context = register_allocator()->NewRegister();
@@ -3369,8 +3310,7 @@
     builder()->LoadContextSlot(execution_context()->reg(),
                                Context::CLOSURE_INDEX);
   } else {
-    DCHECK(closure_scope->is_function_scope() ||
-           closure_scope->is_module_scope());
+    DCHECK(closure_scope->is_function_scope());
     builder()->LoadAccumulatorWithRegister(Register::function_closure());
   }
   execution_result()->SetResultInAccumulator();