Infer whether a variable is assigned

src/ast.cc

 // 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.
 
 #include "src/ast.h"
 
 #include <cmath>  // For isfinite.
 #include "src/builtins.h"
 #include "src/code-stubs.h"
 #include "src/contexts.h"
@@ skipping 47 matching lines @@
          String::Equals(var_proxy->name(),
                         isolate->factory()->undefined_string());
 }
 
 
 VariableProxy::VariableProxy(Zone* zone, Variable* var, int position)
     : Expression(zone, position),
       name_(var->name()),
       var_(NULL),  // Will be set by the call to BindTo.
       is_this_(var->is_this()),
-      is_trivial_(false),
-      is_lvalue_(false),
+      is_assigned_(false),
       interface_(var->interface()) {
   BindTo(var);
 }
 
 
 VariableProxy::VariableProxy(Zone* zone,
                              Handle<String> name,
                              bool is_this,
                              Interface* interface,
                              int position)
     : Expression(zone, position),
       name_(name),
       var_(NULL),
       is_this_(is_this),
-      is_trivial_(false),
-      is_lvalue_(false),
+      is_assigned_(false),
       interface_(interface) {
   // Names must be canonicalized for fast equality checks.
   ASSERT(name->IsInternalizedString());
 }
 
 
 void VariableProxy::BindTo(Variable* var) {
   ASSERT(var_ == NULL);  // must be bound only once
   ASSERT(var != NULL);  // must bind
   ASSERT(!FLAG_harmony_modules || interface_->IsUnified(var->interface()));
   ASSERT((is_this() && var->is_this()) || name_.is_identical_to(var->name()));
   // Ideally CONST-ness should match. However, this is very hard to achieve
   // because we don't know the exact semantics of conflicting (const and
   // non-const) multiple variable declarations, const vars introduced via
   // eval() etc.  Const-ness and variable declarations are a complete mess
   // in JS. Sigh...
   var_ = var;
-  var->set_is_used(true);
+  var->set_is_used();
 }
 
 
 Assignment::Assignment(Zone* zone,
                        Token::Value op,
                        Expression* target,
                        Expression* value,
                        int pos)
     : Expression(zone, pos),
       op_(op),
@@ skipping 1035 matching lines @@
     SNPrintF(buffer, "%d", Smi::cast(*value_)->value());
     str = arr;
   } else {
     str = DoubleToCString(value_->Number(), buffer);
   }
   return isolate_->factory()->NewStringFromAsciiChecked(str);
 }
 
 
 } }  // namespace v8::internal