Infer whether a variable is assigned

src/variables.h

 // Copyright 2011 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_VARIABLES_H_
 #define V8_VARIABLES_H_
 
 #include "src/zone.h"
 #include "src/interface.h"
 
@@ skipping 62 matching lines @@
   Handle<String> name() const { return name_; }
   VariableMode mode() const { return mode_; }
   bool has_forced_context_allocation() const {
     return force_context_allocation_;
   }
   void ForceContextAllocation() {
     ASSERT(mode_ != TEMPORARY);
     force_context_allocation_ = true;
   }
   bool is_used() { return is_used_; }
-  void set_is_used(bool flag) { is_used_ = flag; }
+  void set_is_used() { is_used_ = true; }
+  bool maybe_assigned() { return maybe_assigned_; }
+  void set_maybe_assigned() { maybe_assigned_ = true; }
 
   int initializer_position() { return initializer_position_; }
   void set_initializer_position(int pos) { initializer_position_ = pos; }
 
   bool IsVariable(Handle<String> n) const {
     return !is_this() && name().is_identical_to(n);
   }
 
   bool IsUnallocated() const { return location_ == UNALLOCATED; }
   bool IsParameter() const { return location_ == PARAMETER; }
@@ skipping 54 matching lines @@
   // sloppy 'eval' calls between the reference scope (inclusive) and the
   // binding scope (exclusive).
   Variable* local_if_not_shadowed_;
 
   // Valid as a reference? (const and this are not valid, for example)
   bool is_valid_ref_;
 
   // Usage info.
   bool force_context_allocation_;  // set by variable resolver
   bool is_used_;
+  bool maybe_assigned_;
   InitializationFlag initialization_flag_;
 
   // Module type info.
   Interface* interface_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_VARIABLES_H_