diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 46692bc16c..654814c1e6 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -45,11 +45,11 @@ MacroAssembler::MacroAssembler(void* buffer, int size)
       generating_stub_(false),
       allow_stub_calls_(true),
       root_array_available_(true),
-      code_object_(HEAP->undefined_value()) {
+      code_object_(isolate()->heap()->undefined_value()) {
 }
 
 
-  static intptr_t RootRegisterDelta(ExternalReference other, Isolate* isolate) {
+static intptr_t RootRegisterDelta(ExternalReference other, Isolate* isolate) {
   Address roots_register_value = kRootRegisterBias +
       reinterpret_cast<Address>(isolate->heap()->roots_address());
   intptr_t delta = other.address() - roots_register_value;
diff --git a/test/cctest/test-macro-assembler-x64.cc b/test/cctest/test-macro-assembler-x64.cc
index 15dc6db2d5..c7c67b0588 100755
--- a/test/cctest/test-macro-assembler-x64.cc
+++ b/test/cctest/test-macro-assembler-x64.cc
@@ -95,6 +95,7 @@ typedef int (*F0)();
 static void EntryCode(MacroAssembler* masm) {
   // Smi constant register is callee save.
   __ push(v8::internal::kSmiConstantRegister);
+  __ push(v8::internal::kRootRegister);
   __ InitializeSmiConstantRegister();
   __ InitializeRootRegister();
 }
@@ -106,6 +107,7 @@ static void ExitCode(MacroAssembler* masm) {
   __ cmpq(rdx, v8::internal::kSmiConstantRegister);
   __ movq(rdx, Immediate(-1));
   __ cmovq(not_equal, rax, rdx);
+  __ pop(v8::internal::kRootRegister);
   __ pop(v8::internal::kSmiConstantRegister);
 }