[modules] Introduce new VariableLocation for module imports/exports.

src/globals.h

 // Copyright 2012 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.
 
 #ifndef V8_GLOBALS_H_
 #define V8_GLOBALS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 867 matching lines @@
 
 // The order of this enum has to be kept in sync with the predicates below.
 enum VariableMode {
   // User declared variables:
   VAR,  // declared via 'var', and 'function' declarations
 
   CONST_LEGACY,  // declared via legacy 'const' declarations
 
   LET,  // declared via 'let' declarations (first lexical)
 
-  // TODO(neis): Is it correct to make this one of the lexical modes?
-  IMPORT,  // declared via 'import' declarations (except namespace imports)
-
   CONST,  // declared via 'const' declarations (last lexical)
 
   // Variables introduced by the compiler:
   TEMPORARY,  // temporary variables (not user-visible), stack-allocated
               // unless the scope as a whole has forced context allocation
 
   DYNAMIC,  // always require dynamic lookup (we don't know
             // the declaration)
 
   DYNAMIC_GLOBAL,  // requires dynamic lookup, but we know that the
@@ skipping 15 matching lines @@
   return mode >= VAR && mode <= CONST;
 }
 
 
 inline bool IsLexicalVariableMode(VariableMode mode) {
   return mode >= LET && mode <= CONST;
 }
 
 
 inline bool IsImmutableVariableMode(VariableMode mode) {
-  return mode == CONST || mode == CONST_LEGACY || mode == IMPORT;
+  return mode == CONST || mode == CONST_LEGACY;
 }
 
-
 enum class VariableLocation {
   // Before and during variable allocation, a variable whose location is
   // not yet determined.  After allocation, a variable looked up as a
   // property on the global object (and possibly absent).  name() is the
   // variable name, index() is invalid.
   UNALLOCATED,
 
   // A slot in the parameter section on the stack.  index() is the
   // parameter index, counting left-to-right.  The receiver is index -1;
   // the first parameter is index 0.
@@ skipping 10 matching lines @@
 
   // An indexed slot in a script context that contains a respective global
   // property cell.  name() is the variable name, index() is the variable
   // index in the context object on the heap, starting at 0.  scope() is the
   // corresponding script scope.
   GLOBAL,
 
   // A named slot in a heap context.  name() is the variable name in the
   // context object on the heap, with lookup starting at the current
   // context.  index() is invalid.
-  LOOKUP
+  LOOKUP,
+
+  // A named slot in a module's export table.
+  MODULE
 };
 
-
 // ES6 Draft Rev3 10.2 specifies declarative environment records with mutable
 // and immutable bindings that can be in two states: initialized and
 // uninitialized. In ES5 only immutable bindings have these two states. When
 // accessing a binding, it needs to be checked for initialization. However in
 // the following cases the binding is initialized immediately after creation
 // so the initialization check can always be skipped:
 // 1. Var declared local variables.
 //      var foo;
 // 2. A local variable introduced by a function declaration.
 //      function foo() {}
@@ skipping 174 matching lines @@
   return static_cast<uint32_t>(bit_cast<uintptr_t>(address) >>
                                kPointerSizeLog2);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 namespace i = v8::internal;
 
 #endif  // V8_GLOBALS_H_