ARM: Implement code stub for object literal creation.

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 61bdf68a13a0998600954aa377b5418e4fe125a8..9807323792d06d14fffe3d7edcad607aa9555cdf 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -4327,18 +4327,29 @@ void LCodeGen::DoArrayLiteral(LArrayLiteral* instr) {
 
 
 void LCodeGen::DoObjectLiteral(LObjectLiteral* instr) {
+  Handle<FixedArray> constant_properties =
+      instr->hydrogen()->constant_properties();
+
   __ ldr(r4, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
   __ ldr(r4, FieldMemOperand(r4, JSFunction::kLiteralsOffset));
   __ mov(r3, Operand(Smi::FromInt(instr->hydrogen()->literal_index())));
-  __ mov(r2, Operand(instr->hydrogen()->constant_properties()));
-  __ mov(r1, Operand(Smi::FromInt(instr->hydrogen()->fast_elements() ? 1 : 0)));
+  __ mov(r2, Operand(constant_properties));
+  int flags = instr->hydrogen()->fast_elements()
+      ? ObjectLiteral::kFastElements
+      : ObjectLiteral::kNoFlags;
+  __ mov(r1, Operand(Smi::FromInt(flags)));
   __ Push(r4, r3, r2, r1);
 
   // Pick the right runtime function to call.
+  int properties_count = constant_properties->length() / 2;
   if (instr->hydrogen()->depth() > 1) {
     CallRuntime(Runtime::kCreateObjectLiteral, 4, instr);
-  } else {
+  } else if (flags != ObjectLiteral::kFastElements ||
+      properties_count > FastCloneShallowObjectStub::kMaximumClonedProperties) {
     CallRuntime(Runtime::kCreateObjectLiteralShallow, 4, instr);
+  } else {
+    FastCloneShallowObjectStub stub(properties_count);
+    CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
   }
 }