Call a stub for the write barrier on ARM. This is a step

src/arm/code-stubs-arm.cc

 // Copyright 2011 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 4385 matching lines @@
                              RegExpImpl::kLastCaptureCountOffset));
   // Store last subject and last input.
   __ str(subject,
          FieldMemOperand(last_match_info_elements,
                          RegExpImpl::kLastSubjectOffset));
   __ mov(r2, subject);
   __ RecordWriteField(last_match_info_elements,
                       RegExpImpl::kLastSubjectOffset,
                       r2,
                       r7,
+                      kLRHasNotBeenSaved,
                       kDontSaveFPRegs);
   __ str(subject,
          FieldMemOperand(last_match_info_elements,
                          RegExpImpl::kLastInputOffset));
   __ RecordWriteField(last_match_info_elements,
                       RegExpImpl::kLastInputOffset,
                       subject,
                       r7,
+                      kLRHasNotBeenSaved,
                       kDontSaveFPRegs);
 
   // Get the static offsets vector filled by the native regexp code.
   ExternalReference address_of_static_offsets_vector =
       ExternalReference::address_of_static_offsets_vector(isolate);
   __ mov(r2, Operand(address_of_static_offsets_vector));
 
   // r1: number of capture registers
   // r2: offsets vector
   Label next_capture, done;
@@ skipping 2017 matching lines @@
   __ bind(&in_dictionary);
   __ mov(result, Operand(1));
   __ Ret();
 
   __ bind(&not_in_dictionary);
   __ mov(result, Operand(0));
   __ Ret();
 }
 
 
+// Takes the input in 3 registers: address_ value_ and object_.  A pointer to
+// the value has just been written into the object, now this stub makes sure
+// we keep the GC informed.  The word in the object where the value has been
+// written is in the address register.
+void RecordWriteStub::Generate(MacroAssembler* masm) {
+  if (remembered_set_action_ == EMIT_REMEMBERED_SET) {
+    __ RememberedSetHelper(
+        address_, value_, save_fp_regs_mode_, MacroAssembler::kReturnAtEnd);
+  }
+  __ Ret();
+}
+
+
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM