diff --git a/abi-perf-test b/abi-perf-test
index 8bd017b1..3473412c 100755
--- a/abi-perf-test
+++ b/abi-perf-test
@@ -59,7 +59,6 @@ cmake --build build -j$(nproc)
 
 echo "** saving old library and size information **"
 
-$source/check_abi check-sizes --lib build/libqpdf/libqpdf.so
 ./build/qpdf/sizes >| $work/old/sizes
 cp build/libqpdf/libqpdf.so.*.* $work/old
 
diff --git a/qpdf/sizes.cc b/qpdf/sizes.cc
index 12843ab2..cbec5cd5 100644
--- a/qpdf/sizes.cc
+++ b/qpdf/sizes.cc
@@ -108,6 +108,7 @@ main()
     print_size(QPDFNumberTreeObjectHelper);
     print_size(QPDFNumberTreeObjectHelper::iterator);
     print_size(QPDFObjGen);
+    print_size(QPDFObjGen::set);
     print_size(QPDFObjectHandle);
     print_size(QPDFObjectHandle::ParserCallbacks);
     print_size(QPDFObjectHandle::QPDFArrayItems);