Don't use LdMethodFld

Author: ShortDevelopment

lib/Runtime/ByteCode/ByteCodeEmitter.cpp

@@ -7925,10 +7925,15 @@ Js::ArgSlot EmitNewObjectOfConstants(
     return actualArgCount;
 }
 
-void EmitMethodFld(bool isRoot, bool isScoped, Js::RegSlot location, Js::RegSlot callObjLocation, Js::PropertyId propertyId, ByteCodeGenerator *byteCodeGenerator, FuncInfo *funcInfo, bool registerCacheIdForCall = true)
+void EmitMethodFld(bool isRoot, bool isScoped, bool isNullPropagating, Js::RegSlot location, Js::RegSlot callObjLocation, Js::PropertyId propertyId, ByteCodeGenerator *byteCodeGenerator, FuncInfo *funcInfo, bool registerCacheIdForCall = true)
 {
     Js::OpCode opcode;
-    if (!isRoot)
+    if (isNullPropagating)
+    {
+        Assert(!isRoot);
+        opcode = (isScoped || !isRoot) ? Js::OpCode::LdFld : Js::OpCode::LdRootFld;
+    }
+    else if (!isRoot)
     {
         if (callObjLocation == funcInfo->frameObjRegister)
         {
@@ -7975,8 +7980,9 @@ void EmitMethodFld(ParseNode *pnode, Js::RegSlot callObjLocation, Js::PropertyId
     bool isRoot = pnode->nop == knopName && (pnode->AsParseNodeName()->sym == nullptr || pnode->AsParseNodeName()->sym->GetIsGlobal());
     bool isScoped = (byteCodeGenerator->GetFlags() & fscrEval) != 0 ||
         (isRoot && callObjLocation != ByteCodeGenerator::RootObjectRegister);
+    bool isNullPropagating = (knopIndex == pnode->nop || knopDot == pnode->nop) && pnode->AsParseNodeBin()->isNullPropagating;
 
-    EmitMethodFld(isRoot, isScoped, pnode->location, callObjLocation, propertyId, byteCodeGenerator, funcInfo, registerCacheIdForCall);
+    EmitMethodFld(isRoot, isScoped, isNullPropagating, pnode->location, callObjLocation, propertyId, byteCodeGenerator, funcInfo, registerCacheIdForCall);
 }
 
 // lhs.apply(this, arguments);
@@ -8704,7 +8710,7 @@ void EmitInvoke(
     ByteCodeGenerator* byteCodeGenerator,
     FuncInfo* funcInfo)
 {
-    EmitMethodFld(false, false, location, callObjLocation, propertyId, byteCodeGenerator, funcInfo);
+    EmitMethodFld(false, false, false, location, callObjLocation, propertyId, byteCodeGenerator, funcInfo);
 
     funcInfo->StartRecordingOutArgs(1);
 
@@ -8724,7 +8730,7 @@ void EmitInvoke(
     FuncInfo* funcInfo,
     Js::RegSlot arg1Location)
 {
-    EmitMethodFld(false, false, location, callObjLocation, propertyId, byteCodeGenerator, funcInfo);
+    EmitMethodFld(false, false, false, location, callObjLocation, propertyId, byteCodeGenerator, funcInfo);
 
     funcInfo->StartRecordingOutArgs(2);