Remove unused pc-descriptor kind kReturn.

runtime/vm/debugger_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"
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/code_patcher.h"
 #include "vm/cpu.h"
 #include "vm/debugger.h"
@@ skipping 37 matching lines @@
 void CodeBreakpoint::PatchCode() {
   ASSERT(!is_enabled_);
   const Code& code = Code::Handle(code_);
   const Instructions& instrs = Instructions::Handle(code.instructions());
   {
     WritableInstructionsScope writable(instrs.EntryPoint(), instrs.size());
     switch (breakpoint_kind_) {
       case PcDescriptors::kIcCall:
       case PcDescriptors::kUnoptStaticCall:
       case PcDescriptors::kRuntimeCall:
-      case PcDescriptors::kClosureCall:
-      case PcDescriptors::kReturn: {
+      case PcDescriptors::kClosureCall: {
         int32_t offset = CodePatcher::GetPoolOffsetAt(pc_);
         ASSERT((offset > 0) && ((offset & 0x7) == 0));
         saved_value_ = static_cast<uword>(offset);
         const uint32_t stub_offset =
             InstructionPattern::OffsetFromPPIndex(
                 Assembler::kBreakpointRuntimeCPIndex);
         CodePatcher::SetPoolOffsetAt(pc_, stub_offset);
         break;
       }
       default:
         UNREACHABLE();
     }
   }
   is_enabled_ = true;
 }
 
 
 void CodeBreakpoint::RestoreCode() {
   ASSERT(is_enabled_);
   const Code& code = Code::Handle(code_);
   const Instructions& instrs = Instructions::Handle(code.instructions());
   {
     WritableInstructionsScope writable(instrs.EntryPoint(), instrs.size());
     switch (breakpoint_kind_) {
       case PcDescriptors::kIcCall:
       case PcDescriptors::kUnoptStaticCall:
       case PcDescriptors::kClosureCall:
-      case PcDescriptors::kRuntimeCall:
-      case PcDescriptors::kReturn: {
+      case PcDescriptors::kRuntimeCall: {
         CodePatcher::SetPoolOffsetAt(pc_, static_cast<int32_t>(saved_value_));
         break;
       }
       default:
         UNREACHABLE();
     }
   }
   is_enabled_ = false;
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64