Improve array to string conversion.

src/arm/full-codegen-arm.cc

Index: src/arm/full-codegen-arm.cc
diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index 7cb402e636b25903a995206b9cc48f1d82ef144c..39047e93b1d7fcc6f2bdd4676e86f19d2dc374f4 100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -3138,6 +3138,37 @@ void FullCodeGenerator::EmitDateField(CallRuntime* expr) {
 }
 
 
+void FullCodeGenerator::EmitOneByteSeqStringSetChar(CallRuntime* expr) {
+  ZoneList<Expression*>* args = expr->arguments();
+  ASSERT_EQ(3, args->length());
+
+  VisitForStackValue(args->at(1));  // index
+  VisitForStackValue(args->at(2));  // value
+  __ pop(r2);
+  __ pop(r1);
+  VisitForAccumulatorValue(args->at(0));  // string
+
+  SeqStringSetCharGenerator::Generate(masm_, true, r0, r1, r2);
+  context()->Plug(r0);
+}
+
+
+void FullCodeGenerator::EmitTwoByteSeqStringSetChar(CallRuntime* expr) {
+  ZoneList<Expression*>* args = expr->arguments();
+  ASSERT_EQ(3, args->length());
+
+  VisitForStackValue(args->at(1));  // index
+  VisitForStackValue(args->at(2));  // value
+  __ pop(r2);
+  __ pop(r1);
+  VisitForAccumulatorValue(args->at(0));  // string
+
+  SeqStringSetCharGenerator::Generate(masm_, false, r0, r1, r2);
+  context()->Plug(r0);
+}
+
+
+
 void FullCodeGenerator::EmitMathPow(CallRuntime* expr) {
   // Load the arguments on the stack and call the runtime function.
   ZoneList<Expression*>* args = expr->arguments();