Cache current thread in a reserved register and use it in LoadIsolate

runtime/vm/assembler_arm64_test.cc

 // Copyright (c) 2013, 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/cpu.h"
 #include "vm/os.h"
@@ skipping 3535 matching lines @@
   double res = EXECUTE_TEST_CODE_DOUBLE(DoubleReturn, test->entry());
   EXPECT_FLOAT_EQ(1.0/sqrt(147000.0), res, 0.0001);
 }
 
 
 // Called from assembler_test.cc.
 // LR: return address.
 // R0: context.
 // R1: value.
 // R2: growable array.
+// R3: current thread.
 ASSEMBLER_TEST_GENERATE(StoreIntoObject, assembler) {
   __ SetupDartSP(kTestStackSpace);
   __ TagAndPushPP();
   __ LoadPoolPointer(PP);
+  __ Push(THR);
   __ Push(CTX);
   __ Push(LR);
   __ mov(CTX, R0);
+  __ mov(THR, R3);
   __ StoreIntoObject(R2,
                      FieldAddress(R2, GrowableObjectArray::data_offset()),
                      R1);
   __ Pop(LR);
   __ Pop(CTX);
+  __ Pop(THR);
   __ PopAndUntagPP();
   __ mov(CSP, SP);
   __ ret();
 }
 
 
 ASSEMBLER_TEST_GENERATE(ComputeRange, assembler) {
   __ SetupDartSP(kTestStackSpace);
   __ TagAndPushPP();
   __ LoadPoolPointer(PP);
@@ skipping 49 matching lines @@
 
   EXPECT_EQ(-1, RANGE_OF(Bool::True().raw()));
 
 #undef RANGE_OF
 }
 
 
 }  // namespace dart
 
 #endif  // defined(TARGET_ARCH_ARM64)