Revert "Lazy deopt without code patching."

runtime/vm/flow_graph_compiler_arm64.cc

 // 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 1088 matching lines @@
       }
     }
   }
 
   EndCodeSourceRange(TokenPosition::kDartCodePrologue);
   VisitBlocks();
 
   __ brk(0);
   ASSERT(assembler()->constant_pool_allowed());
   GenerateDeferredCode();
+
+  BeginCodeSourceRange();
+  if (is_optimizing() && !FLAG_precompiled_mode) {
+    // Leave enough space for patching in case of lazy deoptimization.
+    for (intptr_t i = 0;
+      i < CallPattern::kDeoptCallLengthInInstructions;
+      ++i) {
+      __ orr(R0, ZR, Operand(R0));  // nop
+    }
+    lazy_deopt_return_pc_offset_ = assembler()->CodeSize();
+    __ BranchPatchable(*StubCode::DeoptimizeLazyFromReturn_entry());
+    lazy_deopt_throw_pc_offset_ = assembler()->CodeSize();
+    __ BranchPatchable(*StubCode::DeoptimizeLazyFromThrow_entry());
+  }
+  EndCodeSourceRange(TokenPosition::kDartCodeEpilogue);
 }
 
 
 void FlowGraphCompiler::GenerateCall(TokenPosition token_pos,
                                      const StubEntry& stub_entry,
                                      RawPcDescriptors::Kind kind,
                                      LocationSummary* locs) {
   __ BranchLinkPatchable(stub_entry);
   AddCurrentDescriptor(kind, Thread::kNoDeoptId, token_pos);
   RecordSafepoint(locs);
@@ skipping 788 matching lines @@
 void ParallelMoveResolver::RestoreFpuScratch(FpuRegister reg) {
   __ PopDouble(reg);
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64