Macro assembler functions for pretenure call new.

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 3191199271613443a6dfe3ebdff826e22c28da5c..6b84b0bc1aad2a8377890cc09140d7e0eec7fca9 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -3352,6 +3352,19 @@ void MacroAssembler::AssertName(Register object) {
 }
 
 
+void MacroAssembler::AssertUndefinedOrAllocationSite(Register object) {
+  if (emit_debug_code()) {
+    Label done_checking;
+    AssertNotSmi(object);
+    Cmp(object, isolate()->factory()->undefined_value());
+    j(equal, &done_checking);
+    Cmp(FieldOperand(object, 0), isolate()->factory()->allocation_site_map());
+    Assert(equal, kExpectedUndefinedOrCell);
+    bind(&done_checking);
+  }
+}
+
+
 void MacroAssembler::AssertRootValue(Register src,
                                      Heap::RootListIndex root_value_index,
                                      BailoutReason reason) {