ARM64: Optimize AllocateHeapNumber to use STP.

src/arm64/macro-assembler-arm64-inl.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1391 matching lines @@
 }
 
 
 void MacroAssembler::JumpIfBothNotSmi(Register value1,
                                       Register value2,
                                       Label* not_smi_label) {
   JumpIfEitherSmi(value1, value2, NULL, not_smi_label);
 }
 
 
+void MacroAssembler::ObjectTag(Register tagged_obj, Register obj) {
+  STATIC_ASSERT(kHeapObjectTag == 1);
+  if (emit_debug_code()) {
+    Label ok;
+    Tbz(obj, 0, &ok);
+    Abort(kObjectTagged);
+    Bind(&ok);
+  }
+  Orr(tagged_obj, obj, kHeapObjectTag);
+}
+
+
+void MacroAssembler::ObjectUntag(Register untagged_obj, Register obj) {
+  STATIC_ASSERT(kHeapObjectTag == 1);
+  if (emit_debug_code()) {
+    Label ok;
+    Tbnz(obj, 0, &ok);
+    Abort(kObjectNotTagged);
+    Bind(&ok);
+  }
+  Bic(untagged_obj, obj, kHeapObjectTag);
+}
+
+
 void MacroAssembler::IsObjectNameType(Register object,
                                       Register type,
                                       Label* fail) {
   CompareObjectType(object, type, type, LAST_NAME_TYPE);
   B(hi, fail);
 }
 
 
 void MacroAssembler::IsObjectJSObjectType(Register heap_object,
                                           Register map,
@@ skipping 246 matching lines @@
   // characters are reserved for controlling features of the instrumentation.
   ASSERT(isprint(marker_name[0]) && isprint(marker_name[1]));
 
   InstructionAccurateScope scope(this, 1);
   movn(xzr, (marker_name[1] << 8) | marker_name[0]);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM64_MACRO_ASSEMBLER_ARM64_INL_H_