Fix crash bug when loading const variable in the presence of eval....

src/codegen-ia32.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
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 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3268 matching lines @@
       if (potential_slot != NULL) {
         // Allocate a fresh register to use as a temp in
         // ContextSlotOperandCheckExtensions and to hold the result
         // value.
         value = allocator_->Allocate();
         ASSERT(value.is_valid());
         __ mov(value.reg(),
                ContextSlotOperandCheckExtensions(potential_slot,
                                                  value,
                                                  &slow));
+        if (potential_slot->var()->mode() == Variable::CONST) {
+          __ cmp(value.reg(), Factory::the_hole_value());
+          done.Branch(not_equal, &value);
+          __ mov(value.reg(), Factory::undefined_value());
+        }
         // There is always control flow to slow from

[Kevin Millikin (Chromium), 2009/04/15 10:42:54]

This comment isn't explicit enough.  Could you add "so we have to jump around
it." here and in the ARM version?

         // ContextSlotOperandCheckExtensions.
         done.Jump(&value);
       }
     }
 
     slow.Bind();
     frame_->Push(esi);
     frame_->Push(slot->var()->name());
     if (typeof_state == INSIDE_TYPEOF) {
       value =
@@ skipping 3801 matching lines @@
 
   // Slow-case: Go through the JavaScript implementation.
   __ bind(&slow);
   __ InvokeBuiltin(Builtins::INSTANCE_OF, JUMP_FUNCTION);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal