Revert of [fullcodegen] Remove the hacky %_FastOneByteArrayJoin intrinsic.

src/crankshaft/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/crankshaft/hydrogen.h"
 
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
 #include "src/ast/ast-numbering.h"
@@ skipping 12867 matching lines @@
 
 void HOptimizedGraphBuilder::GenerateGetCachedArrayIndex(CallRuntime* call) {
   DCHECK(call->arguments()->length() == 1);
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
   HValue* value = Pop();
   HGetCachedArrayIndex* result = New<HGetCachedArrayIndex>(value);
   return ast_context()->ReturnInstruction(result, call->id());
 }
 
 
+void HOptimizedGraphBuilder::GenerateFastOneByteArrayJoin(CallRuntime* call) {
+  // Simply returning undefined here would be semantically correct and even
+  // avoid the bailout. Nevertheless, some ancient benchmarks like SunSpider's
+  // string-fasta would tank, because fullcode contains an optimized version.
+  // Obviously the fullcode => Crankshaft => bailout => fullcode dance is
+  // faster... *sigh*
+  return Bailout(kInlinedRuntimeFunctionFastOneByteArrayJoin);
+}
+
+
 void HOptimizedGraphBuilder::GenerateDebugBreakInOptimizedCode(
     CallRuntime* call) {
   Add<HDebugBreak>();
   return ast_context()->ReturnValue(graph()->GetConstant0());
 }
 
 
 void HOptimizedGraphBuilder::GenerateDebugIsActive(CallRuntime* call) {
   DCHECK(call->arguments()->length() == 0);
   HValue* ref =
@@ skipping 637 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8