Disable zapping of code space.

src/flag-definitions.h

 // 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.
 
 // This file defines all of the flags.  It is separated into different section,
 // for Debug, Release, Logging and Profiling, etc.  To add a new flag, find the
 // correct section, and use one of the DEFINE_ macros, without a trailing ';'.
 //
 // This include does not have a guard, because it is a template-style include,
 // which can be included multiple times in different modes.  It expects to have
@@ skipping 667 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,

[jochen (gone - plz use gerrit), 2015/06/30 15:15:09]

can you make the default depend on debug vs release?

[Hannes Payer (out of office), 2015/06/30 15:49:33]

Done.

+DEFINE_BOOL(zap_code_space, false,
             "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(trace_weak_arrays, false, "Trace WeakFixedArray usage")
 DEFINE_BOOL(track_prototype_users, false,
             "Keep track of which maps refer to a given prototype object")
 DEFINE_BOOL(trace_prototype_users, false,
@@ skipping 367 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