X64: Add Crankshaft operation LoadGlobal.

src/x64/assembler-x64.cc

 // Copyright 2010 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 3058 matching lines @@
   EnsureSpace ensure_space(this);
   emitl(data);
 }
 
 
 // Relocation information implementations.
 
 void Assembler::RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data) {
   ASSERT(rmode != RelocInfo::NONE);
   // Don't record external references unless the heap will be serialized.
-  if (rmode == RelocInfo::EXTERNAL_REFERENCE &&
-      !Serializer::enabled() &&
-      !FLAG_debug_code) {
-    return;
+  if (rmode == RelocInfo::EXTERNAL_REFERENCE) {
+#ifdef DEBUG
+    if (!Serializer::enabled()) {
+      Serializer::TooLateToEnableNow();
+    }
+#endif
+    if (!Serializer::enabled() && !FLAG_debug_code) {
+      return;
+    }
   }
   RelocInfo rinfo(pc_, rmode, data);
   reloc_info_writer.Write(&rinfo);
 }
 
 void Assembler::RecordJSReturn() {
   positions_recorder()->WriteRecordedPositions();
   EnsureSpace ensure_space(this);
   RecordRelocInfo(RelocInfo::JS_RETURN);
 }
@@ skipping 23 matching lines @@
   // specially coded on x64 means that it is a relative 32 bit address, as used
   // by branch instructions.
   return (1 << rmode_) & kApplyMask;
 }
 
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64