Add Array.concat builtin for the most common case.

src/runtime.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 1279 matching lines @@
   HandleScope scope;
   ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSObject, holder, 0);
 
   InstallBuiltin(holder, "pop", Builtins::ArrayPop, CompileArrayPopCall);
   InstallBuiltin(holder, "push", Builtins::ArrayPush, CompileArrayPushCall);
   InstallBuiltin(holder, "shift", Builtins::ArrayShift);
   InstallBuiltin(holder, "unshift", Builtins::ArrayUnshift);
   InstallBuiltin(holder, "slice", Builtins::ArraySlice);
   InstallBuiltin(holder, "splice", Builtins::ArraySplice);
+  InstallBuiltin(holder, "concat", Builtins::ArrayConcat);
 
   return *holder;
 }
 
 
 static Object* Runtime_MaterializeRegExpLiteral(Arguments args) {
   HandleScope scope;
   ASSERT(args.length() == 4);
   CONVERT_ARG_CHECKED(FixedArray, literals, 0);
   int index = Smi::cast(args[1])->value();
@@ skipping 7807 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal