Cache lookups at megamorphic call sites in optimized code.

runtime/vm/flow_graph_compiler_x64.h

 // Copyright (c) 2012, 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.
 
 #ifndef VM_FLOW_GRAPH_COMPILER_X64_H_
 #define VM_FLOW_GRAPH_COMPILER_X64_H_
 
 #ifndef VM_FLOW_GRAPH_COMPILER_H_
 #error Include flow_graph_compiler.h instead of flow_graph_compiler_x64.h.
 #endif
@@ skipping 123 matching lines @@
                                  LocationSummary* locs);
 
   void EmitInstanceCall(ExternalLabel* target_label,
                         const ICData& ic_data,
                         const Array& arguments_descriptor,
                         intptr_t argument_count,
                         intptr_t deopt_id,
                         intptr_t token_pos,
                         LocationSummary* locs);
 
+  void EmitMegamorphicInstanceCall(const ICData& ic_data,
+                                   const Array& arguments_descriptor,
+                                   intptr_t argument_count,
+                                   intptr_t deopt_id,
+                                   intptr_t token_pos,
+                                   LocationSummary* locs);
+
   void EmitTestAndCall(const ICData& ic_data,
                        Register class_id_reg,
                        intptr_t arg_count,
                        const Array& arg_names,
                        Label* deopt,
                        intptr_t deopt_id,
                        intptr_t token_index,
                        LocationSummary* locs);
 
   void EmitDoubleCompareBranch(Condition true_condition,
@@ skipping 195 matching lines @@
   // that should be used when deoptimizing we store it in this variable.
   // In future AddDeoptStub should be moved out of the instruction template.
   Environment* pending_deoptimization_env_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphCompiler);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_COMPILER_X64_H_