Setup R10/EDX to be valid Oops before stub calls

runtime/vm/stub_code_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/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
@@ skipping 27 matching lines @@
 void StubCode::GenerateCallToRuntimeStub(Assembler* assembler) {
   const intptr_t isolate_offset = NativeArguments::isolate_offset();
   const intptr_t argc_tag_offset = NativeArguments::argc_tag_offset();
   const intptr_t argv_offset = NativeArguments::argv_offset();
   const intptr_t retval_offset = NativeArguments::retval_offset();
   const intptr_t exitframe_last_param_slot_from_fp = 1;
 
   __ SetPrologueOffset();
   __ Comment("CallToRuntimeStub");
   __ EnterFrame(0);
+  __ SmiUntag(R4);
 
   // Load current Isolate pointer from Context structure into R0.
   __ LoadFieldFromOffset(R0, CTX, Context::isolate_offset(), kNoPP);
 
   // Save exit frame information to enable stack walking as we are about
   // to transition to Dart VM C++ code.
   __ StoreToOffset(SP, R0, Isolate::top_exit_frame_info_offset(), kNoPP);
 
   // Save current Context pointer into Isolate structure.
   __ StoreToOffset(CTX, R0, Isolate::top_context_offset(), kNoPP);
@@ skipping 1871 matching lines @@
   const Register right = R0;
   __ LoadFromOffset(left, SP, 1 * kWordSize, kNoPP);
   __ LoadFromOffset(right, SP, 0 * kWordSize, kNoPP);
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64