ARM: Implement code stub for object literal creation.

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 fcc0bd581363acc1be90a746c0af3492b7114f13..62fad3e5d3aa6b3d39d74f78551532ce9e9f711f 100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -1416,10 +1416,11 @@ void FullCodeGenerator::VisitRegExpLiteral(RegExpLiteral* expr) {
 
 void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
   Comment cmnt(masm_, "[ ObjectLiteral");
+  Handle<FixedArray> constant_properties = expr->constant_properties();
   __ ldr(r3, MemOperand(fp,  JavaScriptFrameConstants::kFunctionOffset));
   __ ldr(r3, FieldMemOperand(r3, JSFunction::kLiteralsOffset));
   __ mov(r2, Operand(Smi::FromInt(expr->literal_index())));
-  __ mov(r1, Operand(expr->constant_properties()));
+  __ mov(r1, Operand(constant_properties));
   int flags = expr->fast_elements()
       ? ObjectLiteral::kFastElements
       : ObjectLiteral::kNoFlags;
@@ -1428,10 +1429,15 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
       : ObjectLiteral::kNoFlags;
   __ mov(r0, Operand(Smi::FromInt(flags)));
   __ Push(r3, r2, r1, r0);
+  int properties_count = constant_properties->length() / 2;
   if (expr->depth() > 1) {
     __ CallRuntime(Runtime::kCreateObjectLiteral, 4);
-  } else {
+  } else if (flags != ObjectLiteral::kFastElements ||
+      properties_count > FastCloneShallowObjectStub::kMaximumClonedProperties) {
     __ CallRuntime(Runtime::kCreateObjectLiteralShallow, 4);
+  } else {
+    FastCloneShallowObjectStub stub(properties_count);
+    __ CallStub(&stub);
   }
 
   // If result_saved is true the result is on top of the stack.  If