[compiler] Allow optimization of top-level eval code.

src/objects.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/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 12755 matching lines @@
   return result;
 }
 
 
 MaybeHandle<SharedFunctionInfo> Script::FindSharedFunctionInfo(
     FunctionLiteral* fun) {
   WeakFixedArray::Iterator iterator(shared_function_infos());
   SharedFunctionInfo* shared;
   while ((shared = iterator.Next<SharedFunctionInfo>())) {
     if (fun->function_token_position() == shared->function_token_position() &&
-        fun->start_position() == shared->start_position()) {
+        fun->start_position() == shared->start_position() &&
+        fun->end_position() == shared->end_position()) {
+      // This method is not used to find top-level SharedFunctionInfo objects,
+      // verify that above checks are sufficient to distinguish top-level code.
+      DCHECK(!shared->is_toplevel());
       return Handle<SharedFunctionInfo>(shared);
     }
   }
   return MaybeHandle<SharedFunctionInfo>();
 }
 
 
 Script::Iterator::Iterator(Isolate* isolate)
     : iterator_(isolate->heap()->script_list()) {}
 
@@ skipping 5889 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8