Probe the symbol table for two character strings in native code...

src/ia32/macro-assembler-ia32.cc

 // Copyright 2006-2009 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 1515 matching lines @@
 
   push(eax);
   push(Immediate(p0));
   push(Immediate(reinterpret_cast<intptr_t>(Smi::FromInt(p1 - p0))));
   CallRuntime(Runtime::kAbort, 2);
   // will not return here
   int3();
 }
 
 
+void MacroAssembler::JumpIfInstanceTypeIsNotSequentialAscii(
+    Register instance_type,
+    Register scratch,
+    Label *failure) {
+  if (!scratch.is(instance_type)) {
+    mov(scratch, instance_type);
+  }
+  and_(scratch,
+       kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask);
+  cmp(scratch, kStringTag | kSeqStringTag | kAsciiStringTag);
+  j(not_equal, failure);
+}
+
+
 void MacroAssembler::JumpIfNotBothSequentialAsciiStrings(Register object1,
                                                          Register object2,
                                                          Register scratch1,
                                                          Register scratch2,
                                                          Label* failure) {
   // Check that both objects are not smis.
   ASSERT_EQ(0, kSmiTag);
   mov(scratch1, Operand(object1));
   and_(scratch1, Operand(object2));
   test(scratch1, Immediate(kSmiTagMask));
@@ skipping 32 matching lines @@
   // Indicate that code has changed.
   CPU::FlushICache(address_, size_);
 
   // Check that the code was patched as expected.
   ASSERT(masm_.pc_ == address_ + size_);
   ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
 }
 
 
 } }  // namespace v8::internal