Precompilation: Generate instance calls as IC calls that can switch to Megamoprhic calls.

runtime/vm/instructions_arm64.h

 // Copyright (c) 2014, 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.
 // Classes that describe assembly patterns as used by inline caches.
 
 #ifndef VM_INSTRUCTIONS_ARM64_H_
 #define VM_INSTRUCTIONS_ARM64_H_
 
 #ifndef VM_INSTRUCTIONS_H_
 #error Do not include instructions_arm64.h directly; use instructions.h instead.
@@ skipping 88 matching lines @@
   const ObjectPool& object_pool_;
 
   uword end_;
   intptr_t native_function_pool_index_;
   intptr_t target_code_pool_index_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeCallPattern);
 };
 
 
+// Instance call that can switch from an IC call to a megamorphic call
+//   load ICData             load MegamorphicCache
+//   call ICLookup stub  ->  call MegamorphicLookup stub
+//   call target             call target
+class SwitchableCallPattern : public ValueObject {
+ public:
+  SwitchableCallPattern(uword pc, const Code& code);
+
+  RawObject* cache() const;
+  void SetCache(const MegamorphicCache& cache) const;
+  void SetLookupStub(const Code& stub) const;
+
+ private:
+  const ObjectPool& object_pool_;
+  intptr_t cache_pool_index_;
+  intptr_t stub_pool_index_;
+
+  DISALLOW_COPY_AND_ASSIGN(SwitchableCallPattern);
+};
+
+
 class ReturnPattern : public ValueObject {
  public:
   explicit ReturnPattern(uword pc);
 
   // bx_lr = 1.
   static const int kLengthInBytes = 1 * Instr::kInstrSize;
 
   int pattern_length_in_bytes() const {
     return kLengthInBytes;
   }
 
   bool IsValid() const;
 
  private:
   const uword pc_;
 };
 
 }  // namespace dart
 
 #endif  // VM_INSTRUCTIONS_ARM64_H_