[crankshaft] Add support for %_ToString.

src/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/hydrogen.h"
 
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
 #include "src/ast-numbering.h"
+#include "src/code-factory.h"
 #include "src/full-codegen/full-codegen.h"
 #include "src/hydrogen-bce.h"
 #include "src/hydrogen-bch.h"
 #include "src/hydrogen-canonicalize.h"
 #include "src/hydrogen-check-elimination.h"
 #include "src/hydrogen-dce.h"
 #include "src/hydrogen-dehoist.h"
 #include "src/hydrogen-environment-liveness.h"
 #include "src/hydrogen-escape-analysis.h"
 #include "src/hydrogen-gvn.h"
@@ skipping 12196 matching lines @@
 
 void HOptimizedGraphBuilder::GenerateToObject(CallRuntime* call) {
   DCHECK_EQ(1, call->arguments()->length());
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
   HValue* value = Pop();
   HValue* result = BuildToObject(value);
   return ast_context()->ReturnValue(result);
 }
 
 
+void HOptimizedGraphBuilder::GenerateToString(CallRuntime* call) {
+  DCHECK_EQ(1, call->arguments()->length());
+  CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
+  Callable callable = CodeFactory::ToString(isolate());
+  HValue* input = Pop();
+  if (input->type().IsString()) {
+    return ast_context()->ReturnValue(input);
+  } else {
+    HValue* stub = Add<HConstant>(callable.code());
+    HValue* values[] = {context(), input};
+    HInstruction* result =
+        New<HCallWithDescriptor>(stub, 0, callable.descriptor(),
+                                 Vector<HValue*>(values, arraysize(values)));
+    return ast_context()->ReturnInstruction(result, call->id());
+  }
+}
+
+
 void HOptimizedGraphBuilder::GenerateIsJSProxy(CallRuntime* call) {
   DCHECK(call->arguments()->length() == 1);
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
   HValue* value = Pop();
   HIfContinuation continuation;
   IfBuilder if_proxy(this);
 
   HValue* smicheck = if_proxy.IfNot<HIsSmiAndBranch>(value);
   if_proxy.And();
   HValue* map = Add<HLoadNamedField>(value, smicheck, HObjectAccess::ForMap());
@@ skipping 1361 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8