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

runtime/vm/assembler_x64_test.cc

 // Copyright (c) 2012, 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_X64)
 
 #include "vm/assembler.h"
 #include "vm/os.h"
 #include "vm/unit_test.h"
@@ skipping 3290 matching lines @@
   double res =
       reinterpret_cast<SquareRootDoubleCode>(test->entry())(kDoubleConst);
   EXPECT_FLOAT_EQ(sqrt(kDoubleConst), res, 0.0001);
 }
 
 
 // Called from assembler_test.cc.
 ASSEMBLER_TEST_GENERATE(StoreIntoObject, assembler) {
   __ pushq(PP);  // Save caller's pool pointer and load a new one here.
   __ LoadPoolPointer(PP);
+  __ pushq(THR);
+  __ movq(THR, CallingConventions::kArg4Reg);
   __ pushq(CTX);
   __ movq(CTX, CallingConventions::kArg1Reg);
   __ StoreIntoObject(CallingConventions::kArg3Reg,
                      FieldAddress(CallingConventions::kArg3Reg,
                                   GrowableObjectArray::data_offset()),
                      CallingConventions::kArg2Reg);
   __ popq(CTX);
+  __ popq(THR);
   __ popq(PP);  // Restore caller's pool pointer.
   __ ret();
 }
 
 
 ASSEMBLER_TEST_GENERATE(DoubleFPUStackMoves, assembler) {
   int64_t l = bit_cast<int64_t, double>(1024.67);
   __ movq(RAX, Immediate(l));
   __ pushq(RAX);
   __ fldl(Address(RSP, 0));
@@ skipping 311 matching lines @@
   EXPECT_EQ(ICData::kInt64RangeBit, range_of(Integer::New(kMaxInt64)));
   EXPECT_EQ(ICData::kInt64RangeBit, range_of(Integer::New(kMinInt64)));
 
   EXPECT_EQ(0, range_of(Bool::True().raw()));
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64