Remove 6 unused flags.

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 115 matching lines @@
             "Optimize object size, Array shift, DOM strings and string +")
 
 // Flags for data representation optimizations
 DEFINE_bool(unbox_double_arrays, true, "automatically unbox arrays of doubles")
 DEFINE_bool(string_slices, true, "use string slices")
 
 // Flags for Crankshaft.
 DEFINE_bool(crankshaft, true, "use crankshaft")
 DEFINE_string(hydrogen_filter, "", "hydrogen use/trace filter")
 DEFINE_bool(use_range, true, "use hydrogen range analysis")
-DEFINE_bool(eliminate_dead_phis, true, "eliminate dead phis")
 DEFINE_bool(use_gvn, true, "use hydrogen global value numbering")
 DEFINE_bool(use_canonicalizing, true, "use hydrogen instruction canonicalizing")
 DEFINE_bool(use_inlining, true, "use function inlining")
 DEFINE_bool(limit_inlining, true, "limit code size growth from inlining")
-DEFINE_bool(eliminate_empty_blocks, true, "eliminate empty blocks")
 DEFINE_bool(loop_invariant_code_motion, true, "loop invariant code motion")
 DEFINE_bool(collect_megamorphic_maps_from_stub_cache,
             true,
             "crankshaft harvests type feedback from stub cache")
 DEFINE_bool(hydrogen_stats, false, "print statistics for hydrogen")
 DEFINE_bool(trace_hydrogen, false, "trace generated hydrogen to file")
 DEFINE_bool(trace_inlining, false, "trace inlining decisions")
 DEFINE_bool(trace_alloc, false, "trace register allocator")
 DEFINE_bool(trace_all_uses, false, "trace all use positions")
 DEFINE_bool(trace_range, false, "trace range analysis")
@@ skipping 142 matching lines @@
 #endif
 
 // macro-assembler-ia32.cc
 DEFINE_bool(native_code_counters, false,
             "generate extra code for manipulating stats counters")
 
 // mark-compact.cc
 DEFINE_bool(always_compact, false, "Perform compaction on every full GC")
 DEFINE_bool(lazy_sweeping, true,
             "Use lazy sweeping for old pointer and data spaces")
-DEFINE_bool(cleanup_caches_in_maps_at_gc, true,
-            "Flush code caches in maps during mark compact cycle.")
 DEFINE_bool(never_compact, false,
             "Never perform compaction on full GC - testing only")
 DEFINE_bool(compact_code_space, false,
             "Compact code space on full non-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_int(random_seed, 0,
            "Default seed for initializing random generator "
            "(0, the default, means to use system random).")
 
-DEFINE_bool(canonicalize_object_literal_maps, true,
-            "Canonicalize maps for object literals.")
-
-DEFINE_int(max_map_space_pages, MapSpace::kMaxMapPageIndex - 1,
-           "Maximum number of pages in map space which still allows to encode "
-           "forwarding pointers.  That's actually a constant, but it's useful "
-           "to control it with a flag for better testing.")
-
 // objects.cc
 DEFINE_bool(use_verbose_printer, true, "allows verbose printing")
 
 // parser.cc
 DEFINE_bool(allow_natives_syntax, false, "allow natives syntax")
 
 // simulator-arm.cc and simulator-mips.cc
 DEFINE_bool(trace_sim, false, "Trace simulator execution")
 DEFINE_bool(check_icache, false,
             "Check icache flushes in ARM and MIPS simulator")
@@ skipping 129 matching lines @@
 DEFINE_bool(trace_ic, false, "trace inline cache state transitions")
 
 // objects.cc
 DEFINE_bool(trace_normalization,
             false,
             "prints when objects are turned into dictionaries.")
 
 // runtime.cc
 DEFINE_bool(trace_lazy, false, "trace lazy compilation")
 
-// serialize.cc
-DEFINE_bool(debug_serialization, false,
-            "write debug information into the snapshot.")
-
 // spaces.cc
 DEFINE_bool(collect_heap_spill_statistics, false,
             "report heap spill statistics along with heap_stats "
             "(requires heap_stats)")
 
 DEFINE_bool(trace_isolates, false, "trace isolate state changes")
 
 // VM state
 DEFINE_bool(log_state_changes, false, "Log state changes.")
 
@@ skipping 87 matching lines @@
 #undef DEFINE_bool
 #undef DEFINE_int
 #undef DEFINE_string
 #undef DEFINE_implication
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS