qdoc crash when generic documents of qtbase

Using host libthread_db library "/usr/lib/libthread_db.so.1".
Core was generated by `/usr/bin/qdoc -outputdir /home/zccrs/projects/qtbase/build/doc/qtcore -installd'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00005560edee5e5a in QListData::size (this=0x18) at /usr/include/qt/QtCore/qlist.h:115
115	    inline int size() const noexcept { return int(d->end - d->begin); }   // q6sizetype
(gdb) bt
#0  0x00005560edee5e5a in QListData::size (this=0x18) at /usr/include/qt/QtCore/qlist.h:115
#1  0x00005560edee65b1 in QList<QString>::operator[] (this=0x18, i=0) at /usr/include/qt/QtCore/qlist.h:575
#2  0x00005560edee6083 in Atom::string (this=0x0) at /home/zccrs/projects/qttools/src/qdoc/atom.h:173
#3  0x00005560ee039bc7 in WebXMLGenerator::startLink (this=0x7ffdc8cc0530, writer=..., atom=0x0, node=0x5560eea13380, link=...) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:751
#4  0x00005560ee03a630 in WebXMLGenerator::generateAnnotatedList (this=0x7ffdc8cc0530, writer=..., relative=0x5560f46a33f0, nodeList=...) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:856
#5  0x00005560ee036eb1 in WebXMLGenerator::append (this=0x7ffdc8cc0530, writer=..., node=0x5560f46a33f0) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:244
#6  0x00005560ee012af0 in QDocIndexFiles::generateIndexSection (this=0x5560f7d31d90, writer=..., node=0x5560f46a33f0, post=0x7ffdc8cc06d0) at /home/zccrs/projects/qttools/src/qdoc/qdocindexfiles.cpp:1314
#7  0x00005560ee0366bd in WebXMLGenerator::generateIndexSections (this=0x7ffdc8cc0530, writer=..., node=0x5560f46a33f0) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:169
#8  0x00005560ee035eb1 in WebXMLGenerator::generatePageNode (this=0x7ffdc8cc0530, pn=0x5560f46a33f0) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:111
#9  0x00005560ee0370c8 in WebXMLGenerator::generateDocumentation (this=0x7ffdc8cc0530, node=0x5560f46a33f0) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:267
#10 0x00005560ee03722e in WebXMLGenerator::generateDocumentation (this=0x7ffdc8cc0530, node=0x5560f35b5a48) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:279
#11 0x00005560edf8b012 in Generator::generateDocs (this=0x7ffdc8cc0530) at /home/zccrs/projects/qttools/src/qdoc/generator.cpp:1669
#12 0x00005560edfab9f9 in HtmlGenerator::generateDocs (this=0x7ffdc8cc0530) at /home/zccrs/projects/qttools/src/qdoc/htmlgenerator.cpp:276
#13 0x00005560edfd9f10 in processQdocconfFile (fileName=...) at /home/zccrs/projects/qttools/src/qdoc/main.cpp:514
#14 0x00005560edfda6b2 in main (argc=28, argv=0x7ffdc8cc0808) at /home/zccrs/projects/qttools/src/qdoc/main.cpp:605
(gdb) f 3
#3  0x00005560ee039bc7 in WebXMLGenerator::startLink (this=0x7ffdc8cc0530, writer=..., atom=0x0, node=0x5560eea13380, link=...) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:751
751	        if (!atom->string().isEmpty())
(gdb) bt
#0  0x00005560edee5e5a in QListData::size (this=0x18) at /usr/include/qt/QtCore/qlist.h:115
#1  0x00005560edee65b1 in QList<QString>::operator[] (this=0x18, i=0) at /usr/include/qt/QtCore/qlist.h:575
#2  0x00005560edee6083 in Atom::string (this=0x0) at /home/zccrs/projects/qttools/src/qdoc/atom.h:173
#3  0x00005560ee039bc7 in WebXMLGenerator::startLink (this=0x7ffdc8cc0530, writer=..., atom=0x0, node=0x5560eea13380, link=...) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:751
#4  0x00005560ee03a630 in WebXMLGenerator::generateAnnotatedList (this=0x7ffdc8cc0530, writer=..., relative=0x5560f46a33f0, nodeList=...) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:856
#5  0x00005560ee036eb1 in WebXMLGenerator::append (this=0x7ffdc8cc0530, writer=..., node=0x5560f46a33f0) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:244
#6  0x00005560ee012af0 in QDocIndexFiles::generateIndexSection (this=0x5560f7d31d90, writer=..., node=0x5560f46a33f0, post=0x7ffdc8cc06d0) at /home/zccrs/projects/qttools/src/qdoc/qdocindexfiles.cpp:1314
#7  0x00005560ee0366bd in WebXMLGenerator::generateIndexSections (this=0x7ffdc8cc0530, writer=..., node=0x5560f46a33f0) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:169
#8  0x00005560ee035eb1 in WebXMLGenerator::generatePageNode (this=0x7ffdc8cc0530, pn=0x5560f46a33f0) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:111
#9  0x00005560ee0370c8 in WebXMLGenerator::generateDocumentation (this=0x7ffdc8cc0530, node=0x5560f46a33f0) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:267
#10 0x00005560ee03722e in WebXMLGenerator::generateDocumentation (this=0x7ffdc8cc0530, node=0x5560f35b5a48) at /home/zccrs/projects/qttools/src/qdoc/webxmlgenerator.cpp:279
#11 0x00005560edf8b012 in Generator::generateDocs (this=0x7ffdc8cc0530) at /home/zccrs/projects/qttools/src/qdoc/generator.cpp:1669
#12 0x00005560edfab9f9 in HtmlGenerator::generateDocs (this=0x7ffdc8cc0530) at /home/zccrs/projects/qttools/src/qdoc/htmlgenerator.cpp:276
#13 0x00005560edfd9f10 in processQdocconfFile (fileName=...) at /home/zccrs/projects/qttools/src/qdoc/main.cpp:514
#14 0x00005560edfda6b2 in main (argc=28, argv=0x7ffdc8cc0808) at /home/zccrs/projects/qttools/src/qdoc/main.cpp:605
quit)