Revert of [modules] Basic support of exports

src/interpreter/bytecode-generator.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/interpreter/bytecode-generator.h"
 
 #include "src/ast/compile-time-value.h"
 #include "src/ast/scopes.h"
 #include "src/code-stubs.h"
 #include "src/compilation-info.h"
@@ skipping 725 matching lines @@
   // Initialize control scope.
   ControlScopeForTopLevel control(this);
 
   RegisterAllocationScope register_scope(this);
 
   if (IsResumableFunction(info()->literal()->kind())) {
     generator_state_ = register_allocator()->NewRegister();
     VisitGeneratorPrologue();
   }
 
+  // Build function context only if there are context allocated variables.
   if (scope()->NeedsContext()) {
     // Push a new inner context scope for the function.
     VisitNewLocalFunctionContext();
     ContextScope local_function_context(this, scope(), false);
     VisitBuildLocalActivationContext();
     GenerateBytecodeBody();
   } else {
     GenerateBytecodeBody();
   }
 
@@ skipping 176 matching lines @@
 
       Register name = register_allocator()->NewRegister();
 
       builder()
           ->LoadLiteral(variable->name())
           .StoreAccumulatorInRegister(name)
           .CallRuntime(Runtime::kDeclareEvalVar, name, 1);
       break;
     }
     case VariableLocation::MODULE:
-      // Nothing to do here.
-      break;
+      UNREACHABLE();
   }
 }
 
 void BytecodeGenerator::VisitFunctionDeclaration(FunctionDeclaration* decl) {
   Variable* variable = decl->proxy()->var();
   DCHECK(variable->mode() == LET || variable->mode() == VAR);
   switch (variable->location()) {
     case VariableLocation::UNALLOCATED: {
       FeedbackVectorSlot slot = decl->proxy()->VariableFeedbackSlot();
       globals_builder()->AddFunctionDeclaration(slot, decl->fun());
@@ skipping 18 matching lines @@
       Register name = register_allocator()->NextConsecutiveRegister();
       Register literal = register_allocator()->NextConsecutiveRegister();
       builder()->LoadLiteral(variable->name()).StoreAccumulatorInRegister(name);
 
       VisitForAccumulatorValue(decl->fun());
       builder()->StoreAccumulatorInRegister(literal).CallRuntime(
           Runtime::kDeclareEvalFunction, name, 2);
       break;
     }
     case VariableLocation::MODULE:
-      DCHECK(variable->mode() == LET);
-      VisitForAccumulatorValue(decl->fun());
-      VisitVariableAssignment(variable, Token::INIT,
-                              FeedbackVectorSlot::Invalid());
-      break;
+      UNREACHABLE();
   }
 }
 
 void BytecodeGenerator::VisitDeclarations(
     ZoneList<Declaration*>* declarations) {
   RegisterAllocationScope register_scope(this);
   DCHECK(globals_builder()->empty());
   for (int i = 0; i < declarations->length(); i++) {
     RegisterAllocationScope register_scope(this);
     Visit(declarations->at(i));
@@ skipping 978 matching lines @@
       }
 
       builder()->LoadContextSlot(context_reg, variable->index());
       BuildHoleCheckForVariableLoad(variable);
       break;
     }
     case VariableLocation::LOOKUP: {
       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();
 }
 
 void BytecodeGenerator::VisitVariableLoadForAccumulatorValue(
     Variable* variable, FeedbackVectorSlot slot, TypeofMode typeof_mode) {
   AccumulatorResultScope accumulator_result(this);
   VisitVariableLoad(variable, slot, typeof_mode);
 }
 
@@ skipping 177 matching lines @@
         builder()->StoreContextSlot(context_reg, variable->index());
       } else if (variable->throw_on_const_assignment(language_mode())) {
         builder()->CallRuntime(Runtime::kThrowConstAssignError, Register(), 0);
       }
       break;
     }
     case VariableLocation::LOOKUP: {
       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();
   }
 }
 
 void BytecodeGenerator::VisitAssignment(Assignment* expr) {
   DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
   Register object, key, home_object, value;
   Handle<String> name;
 
   // Left-hand side can only be a property, a global or a variable slot.
   Property* property = expr->target()->AsProperty();
@@ skipping 936 matching lines @@
 }
 
 void BytecodeGenerator::VisitRewritableExpression(RewritableExpression* expr) {
   Visit(expr->expression());
 }
 
 void BytecodeGenerator::VisitNewLocalFunctionContext() {
   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);
   }
   execution_result()->SetResultInAccumulator();
 }
 
 void BytecodeGenerator::VisitBuildLocalActivationContext() {
   DeclarationScope* scope = this->scope();
 
@@ skipping 126 matching lines @@
   // before a local variable containing the <new.target> is used. Using a label
   // as below flushes the entire pipeline, we should be more specific here.
   BytecodeLabel flush_state_label;
   builder()->Bind(&flush_state_label);
 }
 
 void BytecodeGenerator::VisitFunctionClosureForContext() {
   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();
     builder()
         ->LoadContextSlot(execution_context()->reg(),
                           Context::NATIVE_CONTEXT_INDEX)
         .StoreAccumulatorInRegister(native_context)
         .LoadContextSlot(native_context, Context::CLOSURE_INDEX);
   } else if (closure_scope->is_eval_scope()) {
     // Contexts created by a call to eval have the same closure as the
     // context calling eval, not the anonymous closure containing the eval
     // code. Fetch it from the context.
     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();
 }
 
 // Visits the expression |expr| and places the result in the accumulator.
 void BytecodeGenerator::VisitForAccumulatorValue(Expression* expr) {
   AccumulatorResultScope accumulator_scope(this);
   Visit(expr);
 }
@@ skipping 69 matching lines @@
   return execution_context()->scope()->language_mode();
 }
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return TypeFeedbackVector::GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8