Implement and enable zapping of code space while sweeping.

src/flag-definitions.h

 // Copyright 2012 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
 //       notice, this list of conditions and the following disclaimer.
 //     * 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 554 matching lines @@
 DEFINE_bool(compact_code_space, true,
             "Compact code space on full non-incremental collections")
 DEFINE_bool(incremental_code_compaction, true,
             "Compact code space on full incremental collections")
 DEFINE_bool(cleanup_code_caches_at_gc, true,
             "Flush inline caches prior to mark compact collection and "
             "flush code caches in maps during mark compact cycle.")
 DEFINE_bool(use_marking_progress_bar, true,
             "Use a progress bar to scan large objects in increments when "
             "incremental marking is active.")
+DEFINE_bool(zap_code_space, true,
+            "Zap free memory in code space with 0xCC while sweeping.")
 DEFINE_int(random_seed, 0,
            "Default seed for initializing random generator "
            "(0, the default, means to use system random).")
 
 // objects.cc
 DEFINE_bool(use_verbose_printer, true, "allows verbose printing")
 
 // parser.cc
 DEFINE_bool(allow_natives_syntax, false, "allow natives syntax")
 DEFINE_bool(trace_parse, false, "trace parsing and preparsing")
@@ skipping 332 matching lines @@
 #undef DEFINE_ALIAS_float
 #undef DEFINE_ALIAS_args
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS
 
 #undef COMMA