Add flags for write barrier elimination and local allocation folding.

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 233 matching lines @@
 
 // Flags for Crankshaft.
 DEFINE_bool(crankshaft, true, "use crankshaft")
 DEFINE_string(hydrogen_filter, "*", "optimization filter")
 DEFINE_bool(use_range, true, "use hydrogen range analysis")
 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(use_escape_analysis, false, "use hydrogen escape analysis")
 DEFINE_bool(use_allocation_folding, true, "use allocation folding")
+DEFINE_bool(use_local_allocation_folding, false, "only fold in basic blocks")
+DEFINE_bool(use_write_barrier_elimination, true, "eliminate write barriers")

[Hannes Payer (out of office), 2014/02/14 12:02:52]

We are still eliminating write barriers when this flag is turned off. We should
relate it to the allocate case.

[Michael Starzinger, 2014/02/14 14:37:34]

Done. I adapted the description accordingly and made if more expressive.
Couldn't come up with a better name for the flag itself though.

 DEFINE_int(max_inlining_levels, 5, "maximum number of inlining levels")
 DEFINE_int(max_inlined_source_size, 600,
            "maximum source size in bytes considered for a single inlining")
 DEFINE_int(max_inlined_nodes, 196,
            "maximum number of AST nodes considered for a single inlining")
 DEFINE_int(max_inlined_nodes_cumulative, 400,
            "maximum cumulative number of AST nodes considered for inlining")
 DEFINE_bool(loop_invariant_code_motion, true, "loop invariant code motion")
 DEFINE_bool(fast_math, true, "faster (but maybe less accurate) math functions")
 DEFINE_bool(collect_megamorphic_maps_from_stub_cache, true,
@@ skipping 626 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