c++ - gdb 中的奇怪行为

Question

我的代码中遇到了一个非常奇怪的错误。

我在我的程序中使用了一个变量m_requestedStructures，而调试器在检查它时访问了错误的地址。例如，我在代码中有：

qDebug() << "requested: " << m_requestedStructures << " " << &m_requestedStructures

我在这里设置了一个断点。到达断点时，我将打印的值和地址m_requestedStructures与 gdb 正在访问的值和地址进行比较：

requested:  0   0xfce640 
Breakpoint 1
157         qDebug() << "requested: " << m_requestedStructures << " " << &m_requestedStructures;
(gdb) p m_requestedStructures
$5 = -1167616
(gdb) p &m_requestedStructures
$6 = (int *) 0xfce644
(gdb)

可以看出，值和地址都不同。

我看到的另一个症状是我有一个函数，QueueManager::checkPopulation_()我很久以前就删除了它，但是 gdb 仍然尝试制表符完成它，如果我在它上面设置一个断点，它会在函数使用的点中断成为。

在我看来，符号读取不正确。我试过从一个干净的目录重建，但问题仍然存在。有谁知道可能导致此问题的原因或如何解决？

提前致谢！

编辑：我刚刚尝试在我添加的新函数上设置断点。该函数QueueManager::run()出现在 gdb 的选项卡中完成，但是当我尝试设置断点时，我得到

the class GlobalSearch::QueueManager does not have any method named run

此外，检查其他变量，包括本地范围和 QueueManager 的成员，似乎工作正常。

这是编译器/链接器的输出。包含该类的文件是queuemanager.cpp，它是静态库的一部分，libglobalsearch.a在动态库中使用xtalopt.so：

$ make VERBOSE=1 xtalopt
/usr/bin/cmake -H/git/xtalopt-public -B/git/xtalopt-public/build --check-build-system CMakeFiles/Makefile.cmake 0
make -f CMakeFiles/Makefile2 xtalopt
make[1]: Entering directory `/git/xtalopt-public/build'
/usr/bin/cmake -H/git/xtalopt-public -B/git/xtalopt-public/build --check-build-system CMakeFiles/Makefile.cmake 0
/usr/bin/cmake -E cmake_progress_start /git/xtalopt-public/build/CMakeFiles 63
make -f CMakeFiles/Makefile2 src/xtalopt/CMakeFiles/xtalopt.dir/all
make[2]: Entering directory `/git/xtalopt-public/build'
make -f src/spglib/CMakeFiles/spglib.dir/build.make src/spglib/CMakeFiles/spglib.dir/depend
make[3]: Entering directory `/git/xtalopt-public/build'
cd /git/xtalopt-public/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /git/xtalopt-public /git/xtalopt-public/src/spglib /git/xtalopt-public/build /git/xtalopt-public/build/src/spglib /git/xtalopt-public/build/src/spglib/CMakeFiles/spglib.dir/DependInfo.cmake --color=
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[  9%] Built target spglib
make -f src/libssh/CMakeFiles/ssh_static.dir/build.make src/libssh/CMakeFiles/ssh_static.dir/depend
make[3]: Entering directory `/git/xtalopt-public/build'
cd /git/xtalopt-public/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /git/xtalopt-public /git/xtalopt-public/src/libssh /git/xtalopt-public/build /git/xtalopt-public/build/src/libssh /git/xtalopt-public/build/src/libssh/CMakeFiles/ssh_static.dir/DependInfo.cmake --color=
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[ 33%] Built target ssh_static
make -f src/globalsearch/CMakeFiles/globalsearch.dir/build.make src/globalsearch/CMakeFiles/globalsearch.dir/depend
make[3]: Entering directory `/git/xtalopt-public/build'
cd /git/xtalopt-public/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /git/xtalopt-public /git/xtalopt-public/src/globalsearch /git/xtalopt-public/build /git/xtalopt-public/build/src/globalsearch /git/xtalopt-public/build/src/globalsearch/CMakeFiles/globalsearch.dir/DependInfo.cmake --color=
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make -f src/globalsearch/CMakeFiles/globalsearch.dir/build.make src/globalsearch/CMakeFiles/globalsearch.dir/build
make[3]: Entering directory `/git/xtalopt-public/build'
/usr/bin/cmake -E cmake_progress_report /git/xtalopt-public/build/CMakeFiles 
[ 33%] Building CXX object src/globalsearch/CMakeFiles/globalsearch.dir/queuemanager.cpp.o
cd /git/xtalopt-public/build/src/globalsearch && /usr/bin/c++   -DQT_OPENGL_LIB -DQT_GUI_LIB -DQT_CORE_LIB -DQT_PLUGIN -DQT_SHARED -D_HAVE_EXECINFO_H_ -DQT_DEBUG -fPIC -g -I/usr/include/QtOpenGL -I/usr/include/QtGui -I/usr/include/QtCore -I/usr/include/eigen2 -I/git/xtalopt-public/build -I/usr/include/openbabel-2.0 -I/git/xtalopt-public/src   -o CMakeFiles/globalsearch.dir/queuemanager.cpp.o -c /git/xtalopt-public/src/globalsearch/queuemanager.cpp
Linking CXX static library libglobalsearch.a
cd /git/xtalopt-public/build/src/globalsearch && /usr/bin/cmake -P CMakeFiles/globalsearch.dir/cmake_clean_target.cmake
cd /git/xtalopt-public/build/src/globalsearch && /usr/bin/cmake -E cmake_link_script CMakeFiles/globalsearch.dir/link.txt --verbose=1
/usr/bin/ar cr libglobalsearch.a  CMakeFiles/globalsearch.dir/optbase.cpp.o CMakeFiles/globalsearch.dir/queuemanager.cpp.o CMakeFiles/globalsearch.dir/structure.cpp.o CMakeFiles/globalsearch.dir/tracker.cpp.o CMakeFiles/globalsearch.dir/optimizer.cpp.o CMakeFiles/globalsearch.dir/bt.cpp.o CMakeFiles/globalsearch.dir/sshconnection.cpp.o CMakeFiles/globalsearch.dir/sshmanager.cpp.o CMakeFiles/globalsearch.dir/random.cpp.o CMakeFiles/globalsearch.dir/ui/abstractdialog.cpp.o CMakeFiles/globalsearch.dir/ui/abstracttab.cpp.o CMakeFiles/globalsearch.dir/moc_optbase.cxx.o CMakeFiles/globalsearch.dir/moc_queuemanager.cxx.o CMakeFiles/globalsearch.dir/moc_structure.cxx.o CMakeFiles/globalsearch.dir/moc_tracker.cxx.o CMakeFiles/globalsearch.dir/moc_optimizer.cxx.o CMakeFiles/globalsearch.dir/moc_bt.cxx.o CMakeFiles/globalsearch.dir/moc_sshconnection.cxx.o CMakeFiles/globalsearch.dir/moc_sshmanager.cxx.o CMakeFiles/globalsearch.dir/moc_random.cxx.o CMakeFiles/globalsearch.dir/ui/moc_abstractdialog.cxx.o CMakeFiles/globalsearch.dir/ui/moc_abstracttab.cxx.o
/usr/bin/ranlib libglobalsearch.a
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[ 55%] Built target globalsearch
make -f src/xtalopt/CMakeFiles/xtalopt.dir/build.make src/xtalopt/CMakeFiles/xtalopt.dir/depend
make[3]: Entering directory `/git/xtalopt-public/build'
cd /git/xtalopt-public/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /git/xtalopt-public /git/xtalopt-public/src/xtalopt /git/xtalopt-public/build /git/xtalopt-public/build/src/xtalopt /git/xtalopt-public/build/src/xtalopt/CMakeFiles/xtalopt.dir/DependInfo.cmake --color=
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make -f src/xtalopt/CMakeFiles/xtalopt.dir/build.make src/xtalopt/CMakeFiles/xtalopt.dir/build
make[3]: Entering directory `/git/xtalopt-public/build'
Linking CXX shared library xtalopt.so
cd /git/xtalopt-public/build/src/xtalopt && /usr/bin/cmake -E cmake_link_script CMakeFiles/xtalopt.dir/link.txt --verbose=1
/usr/bin/c++  -fPIC  -fPIC -g  -shared -Wl,-soname,xtalopt.so -o xtalopt.so CMakeFiles/xtalopt.dir/extension.cpp.o CMakeFiles/xtalopt.dir/xtalopt.cpp.o CMakeFiles/xtalopt.dir/genetic.cpp.o CMakeFiles/xtalopt.dir/structures/xtal.cpp.o CMakeFiles/xtalopt.dir/optimizers/xtaloptoptimizer.cpp.o CMakeFiles/xtalopt.dir/optimizers/vasp.cpp.o CMakeFiles/xtalopt.dir/optimizers/gulp.cpp.o CMakeFiles/xtalopt.dir/optimizers/pwscf.cpp.o CMakeFiles/xtalopt.dir/optimizers/castep.cpp.o CMakeFiles/xtalopt.dir/testing/xtalopttest.cpp.o CMakeFiles/xtalopt.dir/ui/dialog.cpp.o CMakeFiles/xtalopt.dir/ui/tab_init.cpp.o CMakeFiles/xtalopt.dir/ui/tab_edit.cpp.o CMakeFiles/xtalopt.dir/ui/tab_opt.cpp.o CMakeFiles/xtalopt.dir/ui/tab_sys.cpp.o CMakeFiles/xtalopt.dir/ui/tab_progress.cpp.o CMakeFiles/xtalopt.dir/ui/tab_plot.cpp.o CMakeFiles/xtalopt.dir/ui/tab_log.cpp.o CMakeFiles/xtalopt.dir/moc_extension.cxx.o CMakeFiles/xtalopt.dir/moc_xtalopt.cxx.o CMakeFiles/xtalopt.dir/moc_genetic.cxx.o CMakeFiles/xtalopt.dir/structures/moc_xtal.cxx.o CMakeFiles/xtalopt.dir/optimizers/moc_xtaloptoptimizer.cxx.o CMakeFiles/xtalopt.dir/optimizers/moc_vasp.cxx.o CMakeFiles/xtalopt.dir/optimizers/moc_gulp.cxx.o CMakeFiles/xtalopt.dir/optimizers/moc_pwscf.cxx.o CMakeFiles/xtalopt.dir/optimizers/moc_castep.cxx.o CMakeFiles/xtalopt.dir/testing/moc_xtalopttest.cxx.o CMakeFiles/xtalopt.dir/ui/moc_dialog.cxx.o CMakeFiles/xtalopt.dir/ui/moc_tab_init.cxx.o CMakeFiles/xtalopt.dir/ui/moc_tab_edit.cxx.o CMakeFiles/xtalopt.dir/ui/moc_tab_opt.cxx.o CMakeFiles/xtalopt.dir/ui/moc_tab_sys.cxx.o CMakeFiles/xtalopt.dir/ui/moc_tab_progress.cxx.o CMakeFiles/xtalopt.dir/ui/moc_tab_plot.cxx.o CMakeFiles/xtalopt.dir/ui/moc_tab_log.cxx.o -lavogadro ../globalsearch/libglobalsearch.a ../spglib/libspglib.a -lQtOpenGL -lGLU -lGL -lSM -lICE -lX11 -lXext -lopenbabel -lQtGui -lQtCore ../libssh/libssh_static.a -lnsl -lresolv -lrt -lz -lssl -lcrypto 
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Answer 1

我终于设法弄清楚了！就是这样：

在 gdb 中，我使用info shared. 我将其复制到一个文本文件shared.txt中，并使用以下命令提取库名称：

cat shared.txt | grep -v \*|grep -v quit---|grep -v Syms\ Read|grep -v \(gdb\)|awk '{print $4}'>libs

从那里，我检查了每个库中的符号：

for i in `cat libs|xargs`;do nm --demangle $i|grep checkPopulation; if [ $? -eq 0 ]; then echo \($i\); fi;done

它打印所有包含“checkPopulation”的符号，后跟包含每个符号的库的名称。我的输出：

000adb18 T GlobalSearch::QueueManager::checkPopulation()
000adb8a T GlobalSearch::QueueManager::checkPopulation_()
(/usr/lib/avogadro/1_1/contrib/randomdock.so)
000db682 T GlobalSearch::QueueManager::checkPopulation()
(/usr/lib/avogadro/1_1/contrib/xtalopt.so)

所以这个“幻影”checkPopulation_符号来自 randomdock.so，它是很久以前针对旧版本的 static 构建的libglobalsearch.a，其中包含现在删除的GlobalSearch::QueueManager::checkPopulation_(). 删除 randomdock.so 会导致一切正常运行。

感谢所有的建议——我在跟踪这个问题时当然学到了一些新的 gdb 技巧。这里也有关于破坏 API 的课程；-)

Answer 2

仅供参考：

Grep有一个-e开关，因此您可以一次处理多个表达式。例如：

grep -v -e \* -e quit--- -e Syms\ Read -e \(gdb\) | awk '{print $4}' > libs

nm有一个-A开关（打印文件名）。例如：

cat libs | xargs nm -A --demangle | grep checkPopulation