[clang][p2719] Module deserialization does not restore allocator flags

When serializing and deserializing a FunctionDecl we don't recover
whether or not the decl was a type aware allocator or destroying
delete, because in the final PR that information was placed in a
side table in ASTContext.

In principle it should be possible to re-do the semantic checks to
determine what these flags should be when deserializing, but it
seems like the most robust path is simply recording the flags
directly in the serialized AST.

Author: ojhunt

clang/lib/Serialization/ASTReaderDecl.cpp

@@ -1076,6 +1076,8 @@ void ASTDeclReader::VisitFunctionDecl(FunctionDecl *FD) {
   FD->setFriendConstraintRefersToEnclosingTemplate(
       FunctionDeclBits.getNextBit());
   FD->setUsesSEHTry(FunctionDeclBits.getNextBit());
+  FD->setIsDestroyingOperatorDelete(FunctionDeclBits.getNextBit());
+  FD->setIsTypeAwareOperatorNewOrDelete(FunctionDeclBits.getNextBit());
 
   FD->EndRangeLoc = readSourceLocation();
   if (FD->isExplicitlyDefaulted())
@@ -1160,6 +1162,7 @@ void ASTDeclReader::VisitFunctionDecl(FunctionDecl *FD) {
       C.registerSYCLEntryPointFunction(FD);
     }
   }
+
 }
 
 void ASTDeclReader::VisitObjCMethodDecl(ObjCMethodDecl *MD) {

clang/lib/Serialization/ASTWriterDecl.cpp

@@ -847,6 +847,8 @@ void ASTDeclWriter::VisitFunctionDecl(FunctionDecl *D) {
   FunctionDeclBits.addBit(D->isInstantiatedFromMemberTemplate());
   FunctionDeclBits.addBit(D->FriendConstraintRefersToEnclosingTemplate());
   FunctionDeclBits.addBit(D->usesSEHTry());
+  FunctionDeclBits.addBit(D->isDestroyingOperatorDelete());
+  FunctionDeclBits.addBit(D->isTypeAwareOperatorNewOrDelete());
   Record.push_back(FunctionDeclBits);
 
   Record.AddSourceLocation(D->getEndLoc());