Optimize AOT's switchable calls for the monomorphic case.

runtime/vm/assembler.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_ASSEMBLER_H_
 #define VM_ASSEMBLER_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/globals.h"
@@ skipping 157 matching lines @@
 
   // When building the C++ tests, assertion code is enabled. To allow
   // asserting that the user of the assembler buffer has ensured the
   // capacity needed for emitting, we add a dummy method in non-debug mode.
   bool HasEnsuredCapacity() const { return true; }
 #endif
 
   // Returns the position in the instruction stream.
   intptr_t GetPosition() const { return cursor_ - contents_; }
 
+  void Reset() { cursor_ = contents_; }
+
  private:
   // The limit is set to kMinimumGap bytes before the end of the data area.
   // This leaves enough space for the longest possible instruction and allows
   // for a single, fast space check per instruction.
   static const intptr_t kMinimumGap = 32;
 
   uword contents_;
   uword cursor_;
   uword limit_;
   AssemblerFixup* fixup_;
@@ skipping 152 matching lines @@
 #include "vm/assembler_arm64.h"
 #elif defined(TARGET_ARCH_MIPS)
 #include "vm/assembler_mips.h"
 #elif defined(TARGET_ARCH_DBC)
 #include "vm/assembler_dbc.h"
 #else
 #error Unknown architecture.
 #endif
 
 #endif  // VM_ASSEMBLER_H_