Support verified heap pointer writes on x64.

runtime/vm/flow_graph_compiler.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_H_
 #define VM_FLOW_GRAPH_COMPILER_H_
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/code_descriptors.h"
@@ skipping 366 matching lines @@
                                Label* is_not_instance_lbl);
   void GenerateListTypeCheck(Register kClassIdReg,
                              Label* is_instance_lbl);
 
   void EmitComment(Instruction* instr);
 
   bool NeedsEdgeCounter(TargetEntryInstr* block);
 
   void EmitEdgeCounter();
 
-#if defined(TARGET_ARCH_IA32)
+#if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64)
   static int32_t EdgeCounterIncrementSizeInBytes();
-#endif  // TARGET_ARCH_IA32
+#endif  // TARGET_ARCH_IA32 || TARGET_ARCH_X64
 
   void EmitOptimizedInstanceCall(ExternalLabel* target_label,
                                  const ICData& ic_data,
                                  intptr_t argument_count,
                                  intptr_t deopt_id,
                                  intptr_t token_pos,
                                  LocationSummary* locs);
 
   void EmitInstanceCall(ExternalLabel* target_label,
                         const ICData& ic_data,
@@ skipping 270 matching lines @@
   intptr_t lazy_deopt_pc_offset_;
 
   ZoneGrowableArray<const ICData*>* deopt_id_to_ic_data_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphCompiler);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_COMPILER_H_