[turbofan] Mark loads of a module (from a module context) immutable.

src/compiler/bytecode-graph-builder.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/compiler/bytecode-graph-builder.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/compilation-info.h"
 #include "src/compiler/compiler-source-position-table.h"
@@ skipping 1050 matching lines @@
   BuildKeyedStore(LanguageMode::SLOPPY);
 }
 
 void BytecodeGraphBuilder::VisitStaKeyedPropertyStrict() {
   BuildKeyedStore(LanguageMode::STRICT);
 }
 
 void BytecodeGraphBuilder::VisitLdaModuleVariable() {
   int32_t cell_index = bytecode_iterator().GetImmediateOperand(0);
   uint32_t depth = bytecode_iterator().GetUnsignedImmediateOperand(1);
-  Node* module = NewNode(
-      javascript()->LoadContext(depth, Context::EXTENSION_INDEX, false));
+  Node* module =
+      NewNode(javascript()->LoadContext(depth, Context::EXTENSION_INDEX, true));
   Node* value = NewNode(javascript()->LoadModule(cell_index), module);
   environment()->BindAccumulator(value);
 }
 
 void BytecodeGraphBuilder::VisitStaModuleVariable() {
   int32_t cell_index = bytecode_iterator().GetImmediateOperand(0);
   uint32_t depth = bytecode_iterator().GetUnsignedImmediateOperand(1);
-  Node* module = NewNode(
-      javascript()->LoadContext(depth, Context::EXTENSION_INDEX, false));
+  Node* module =
+      NewNode(javascript()->LoadContext(depth, Context::EXTENSION_INDEX, true));
   Node* value = environment()->LookupAccumulator();
   NewNode(javascript()->StoreModule(cell_index), module, value);
 }
 
 void BytecodeGraphBuilder::VisitPushContext() {
   Node* new_context = environment()->LookupAccumulator();
   environment()->BindRegister(bytecode_iterator().GetRegisterOperand(0),
                               environment()->Context());
   environment()->SetContext(new_context);
 }
@@ skipping 1209 matching lines @@
         it->source_position().ScriptOffset(), start_position_.InliningId()));
     it->Advance();
   } else {
     DCHECK_GT(it->code_offset(), offset);
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8