Reland of "Store SharedFunctionInfos of a Script in a FixedArray indexed by their ID"

src/runtime/runtime-function.cc

 // Copyright 2014 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/runtime/runtime-utils.h"
 
 #include "src/accessors.h"
 #include "src/arguments.h"
 #include "src/compiler.h"
 #include "src/frames-inl.h"
@@ skipping 186 matching lines @@
   target_shared->set_start_position_and_type(
       source_shared->start_position_and_type());
   target_shared->set_end_position(source_shared->end_position());
   bool was_native = target_shared->native();
   target_shared->set_compiler_hints(source_shared->compiler_hints());
   target_shared->set_opt_count_and_bailout_reason(
       source_shared->opt_count_and_bailout_reason());
   target_shared->set_native(was_native);
   target_shared->set_profiler_ticks(source_shared->profiler_ticks());
   target_shared->set_function_literal_id(source_shared->function_literal_id());
-  SharedFunctionInfo::SetScript(
-      target_shared, Handle<Object>(source_shared->script(), isolate));
+
+  Handle<Object> source_script(source_shared->script(), isolate);
+  if (source_script->IsScript()) {
+    SharedFunctionInfo::SetScript(source_shared,
+                                  isolate->factory()->undefined_value());
+  }
+  SharedFunctionInfo::SetScript(target_shared, source_script);
 
   // Set the code of the target function.
   target->ReplaceCode(source_shared->code());
   DCHECK(target->next_function_link()->IsUndefined(isolate));
 
   Handle<Context> context(source->context());
   target->set_context(*context);
 
   // Make sure we get a fresh copy of the literal vector to avoid cross
   // context contamination, and that the literal vector makes it's way into
@@ skipping 83 matching lines @@
   DCHECK_EQ(1, args.length());
   CONVERT_ARG_HANDLE_CHECKED(JSReceiver, function, 0);
   return function->IsJSBoundFunction()
              ? *JSBoundFunction::ToString(
                    Handle<JSBoundFunction>::cast(function))
              : *JSFunction::ToString(Handle<JSFunction>::cast(function));
 }
 
 }  // namespace internal
 }  // namespace v8