Make subtype test cache stub shared between isolates.

runtime/vm/assembler_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"  // NOLINT
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/longjump.h"
@@ skipping 398 matching lines @@
 void Assembler::LoadExternalLabelFixed(Register dst,
                                        const ExternalLabel* label,
                                        Patchability patchable,
                                        Register pp) {
   const int32_t offset = ObjectPool::element_offset(
       object_pool_wrapper_.FindExternalLabel(label, patchable));
   LoadWordFromPoolOffsetFixed(dst, pp, offset);
 }
 
 
-void Assembler::LoadIsolate(Register dst, Register pp) {
+void Assembler::LoadIsolate(Register dst) {
   ldr(dst, Address(THR, Thread::isolate_offset()));
 }
 
 
 void Assembler::LoadObjectHelper(Register dst,
                                  const Object& object,
                                  Register pp,
                                  bool is_unique) {
   if (Thread::CanLoadFromThread(object)) {
     ldr(dst, Address(THR, Thread::OffsetFromThread(object)));
@@ skipping 527 matching lines @@
   ASSERT(RawObject::kClassIdTagSize == kBitsPerInt32);
   const intptr_t class_id_offset = Object::tags_offset() +
       RawObject::kClassIdTagPos / kBitsPerByte;
   LoadFromOffset(result, object, class_id_offset - kHeapObjectTag, pp,
                  kUnsignedWord);
 }
 
 
 void Assembler::LoadClassById(Register result, Register class_id, Register pp) {
   ASSERT(result != class_id);
-  LoadImmediate(result, Isolate::Current()->class_table()->TableAddress(), pp);
-  LoadFromOffset(result, result, 0, pp);
+  LoadIsolate(result);
+  const intptr_t offset =
+      Isolate::class_table_offset() + ClassTable::table_offset();
+  LoadFromOffset(result, result, offset, pp);
   ldr(result, Address(result, class_id, UXTX, Address::Scaled));
 }
 
 
 void Assembler::LoadClass(Register result, Register object, Register pp) {
   ASSERT(object != TMP);
   LoadClassId(TMP, object, pp);
   LoadClassById(result, TMP, pp);
 }
 
@@ skipping 486 matching lines @@
     add(base, array, Operand(index, LSL, shift));
   }
   const OperandSize size = Address::OperandSizeFor(cid);
   ASSERT(Address::CanHoldOffset(offset, Address::Offset, size));
   return Address(base, offset, Address::Offset, size);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64