Revert "Lazy deopt without code patching."

runtime/vm/code_patcher_x64.cc

 // 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/code_patcher.h"
 #include "vm/cpu.h"
@@ skipping 275 matching lines @@
   }
   return call.target();
 }
 
 
 intptr_t CodePatcher::InstanceCallSizeInBytes() {
   return InstanceCall::kCallPatternSize;
 }
 
 
-void CodePatcher::InsertDeoptimizationCallAt(uword start) {
-  UNREACHABLE();
+void CodePatcher::InsertDeoptimizationCallAt(uword start, uword target) {
+  // The inserted call should not overlap the lazy deopt jump code.
+  ASSERT(start + ShortCallPattern::pattern_length_in_bytes() <= target);
+  *reinterpret_cast<uint8_t*>(start) = 0xE8;
+  ShortCallPattern call(start);
+  call.SetTargetAddress(target);
+  CPU::FlushICache(start, ShortCallPattern::pattern_length_in_bytes());
 }
 
 
 RawFunction* CodePatcher::GetUnoptimizedStaticCallAt(
     uword return_address, const Code& code, ICData* ic_data_result) {
   ASSERT(code.ContainsInstructionAt(return_address));
   UnoptimizedStaticCall static_call(return_address, code);
   ICData& ic_data = ICData::Handle();
   ic_data ^= static_call.ic_data();
   if (ic_data_result != NULL) {
@@ skipping 46 matching lines @@
                                       NativeFunction* target) {
   ASSERT(code.ContainsInstructionAt(return_address));
   NativeCall call(return_address, code);
   *target = call.native_function();
   return call.target();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64