Move megamorphic lookup code to stub instead of inlining. Preformance loss < 5%, instruction size r…

runtime/vm/flow_graph_compiler.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
@@ skipping 20 matching lines @@
     "Instance call always as megamorphic.");
 DEFINE_FLAG(bool, trace_inlining_intervals, false,
     "Inlining interval diagnostics");
 DEFINE_FLAG(bool, enable_simd_inline, true,
     "Enable inlining of SIMD related method calls.");
 DEFINE_FLAG(int, min_optimization_counter_threshold, 5000,
     "The minimum invocation count for a function.");
 DEFINE_FLAG(int, optimization_counter_scale, 2000,
     "The scale of invocation count, by size of the function.");
 DEFINE_FLAG(bool, source_lines, false, "Emit source line as assembly comment.");
+DEFINE_FLAG(bool, use_megamorphic_stub, true, "Out of line megamorphic lookup");
 
 DECLARE_FLAG(bool, code_comments);
 DECLARE_FLAG(int, deoptimize_every);
 DECLARE_FLAG(charp, deoptimize_filter);
 DECLARE_FLAG(bool, disassemble);
 DECLARE_FLAG(bool, disassemble_optimized);
 DECLARE_FLAG(bool, emit_edge_counters);
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, intrinsify);
 DECLARE_FLAG(int, optimization_counter_threshold);
@@ skipping 1663 matching lines @@
 
 
 void FlowGraphCompiler::FrameStateClear() {
   ASSERT(!is_optimizing());
   frame_state_.TruncateTo(0);
 }
 #endif
 
 
 }  // namespace dart