Bug 1776781

Summary: g++ -D_GLIBCXX_USE_CXX11_ABI=0 compiles but executable crashes
Product: Red Hat Enterprise Linux 8 Reporter: Piyush Bhoot <pbhoot>
Component: gccAssignee: Marek Polacek <mpolacek>
gcc sub component: system-version QA Contact: qe-baseos-tools-bugs
Status: CLOSED NOTABUG Docs Contact:
Severity: unspecified    
Priority: unspecified CC: ahajkova, fweimer, jakub, jwakely, ohudlick
Version: 8.1   
Target Milestone: rc   
Target Release: 8.0   
Hardware: Unspecified   
OS: Unspecified   
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Last Closed: 2019-11-26 13:01:33 UTC Type: Bug
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Description Piyush Bhoot 2019-11-26 11:37:12 UTC 
Description of problem:

An C++ executable compiled with -D_GLIBCXX_USE_CXX11_ABI=0 crashes whereas with -D_GLIBCXX_USE_CXX11_ABI=1 (RHEL 8.1 default) does not:


Version-Release number of selected component (if applicable):
gcc version 8.3.1 20190507 (Red Hat 8.3.1-4) (GCC) 

Steps to Reproduce:
test.cpp:
#include <boost/filesystem/path.hpp>
#include <iostream>

int main(int argc, char* argv[]) {
    std::cout << "_GLIBCXX_USE_CXX11_ABI=" << _GLIBCXX_USE_CXX11_ABI << std::endl;
    std::cout << "sizeof(boost::filesystem::path)=" << sizeof(boost::filesystem::path) << std::endl;
    std::cout << boost::filesystem::path(argv[0]).filename().string() << std::endl;
    return 0;
}

$ g++ -D_GLIBCXX_USE_CXX11_ABI=1 -lboost_system -lboost_filesystem test.cpp; ./a.out 
_GLIBCXX_USE_CXX11_ABI=1
sizeof(boost::filesystem::path)=32
a.out
$ g++ -D_GLIBCXX_USE_CXX11_ABI=0 -lboost_system -lboost_filesystem test.cpp; ./a.out 
_GLIBCXX_USE_CXX11_ABI=0
sizeof(boost::filesystem::path)=8
Segmentation fault (core dumped)

Actual results:
Segmentation fault (core dumped)

Expected results:
No segfault
Comment 1 Jakub Jelinek 2019-11-26 11:43:28 UTC 
-D_GLIBCXX_USE_CXX11_ABI=0 is an ABI changing option, so you can only use it in programs where all the C++ code has been compiled with that option, or with libraries like libstdc++.so.6 which do support both ABIs.
That is not the case in your testcase, the libboost_system.so and libboost_filesystem.so libraries are most likely built with the default C++ ABI on RHEL8, so -D_GLIBCXX_USE_CXX11_ABI=1.
Comment 2 Jonathan Wakely 2019-11-26 12:07:39 UTC 
This is not a bug, for the reasons Jakub said. The RHEL8 system libraries (including Boost) use the new ABI, so you cannot expect them to work correctly when you use a different ABI.
Comment 3 Marek Polacek 2019-11-26 13:01:33 UTC 
Invalid code, closing.