[turbofan] Make global variable loads and stores explicit.

src/compiler/opcodes.h

 // Copyright 2013 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_COMPILER_OPCODES_H_
 #define V8_COMPILER_OPCODES_H_
 
 #include <iosfwd>
 
 // Opcodes for control operators.
@@ skipping 96 matching lines @@
   JS_CONVERSION_UNOP_LIST(V)   \
   JS_OTHER_UNOP_LIST(V)
 
 #define JS_OBJECT_OP_LIST(V) \
   V(JSCreate)                \
   V(JSCreateClosure)         \
   V(JSCreateLiteralArray)    \
   V(JSCreateLiteralObject)   \
   V(JSLoadProperty)          \
   V(JSLoadNamed)             \
+  V(JSLoadGlobal)            \
   V(JSStoreProperty)         \
   V(JSStoreNamed)            \
+  V(JSStoreGlobal)           \
   V(JSDeleteProperty)        \
   V(JSHasProperty)           \
   V(JSInstanceOf)
 
 #define JS_CONTEXT_OP_LIST(V) \
   V(JSLoadContext)            \
   V(JSStoreContext)           \
   V(JSLoadDynamicGlobal)      \
   V(JSLoadDynamicContext)     \
   V(JSCreateFunctionContext)  \
@@ skipping 227 matching lines @@
   }
 };
 
 std::ostream& operator<<(std::ostream&, IrOpcode::Value);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_OPCODES_H_