[Bug]: segmentation fault due to constexpr constructor of absl::flags_internal::Flag

[daizhirui]

Describe the issue

When I used abseil-cpp with other libraries like libtorch, I got segmentation fault at FlagRegistry::RegisterFlag. I solved this issue by removing the constexpr keyword from the constructor of absl::flags_internal::Flag.

Steps to reproduce the problem

• create a main.cpp with a blank main function.
• compile main.cpp into an executable and link libtorch and abseil-cpp to it.
• run the executable, a segmentation fault will occur.

What version of Abseil are you using?

20240722.1

What operating system and version are you using?

ArchLinux, kernel version: Linux 6.13.1

What compiler and version are you using?

I tried both GCC13 and GCC14 with C++17.

What build system are you using?

cmake 3.30

Additional context

No response

[derekmauro]

Please provide more details on how to reproduce the problem. We need exact commands.

[daizhirui]

Here is the CMakeLists.txt:

cmake_minimum_required(VERSION 3.30)

project(test_abseil_flags_commandline_flag
    LANGUAGES CXX
)
set(CMAKE_VERBOSE_MAKEFILE ON)
find_package(absl REQUIRED)
set(Torch_DIR /opt/libtorch-cuda/share/cmake/Torch)
find_package(Torch REQUIRED)

find_package(Eigen3 REQUIRED)

# grab all absl libraries
get_target_property(absl_INCLUDE_DIRS absl::core_headers INTERFACE_INCLUDE_DIRECTORIES)
get_target_property(absl_raw_hash_set_path absl::raw_hash_set LOCATION)
get_filename_component(absl_LIB_DIR ${absl_raw_hash_set_path} DIRECTORY)
unset(absl_raw_hash_set_path)
file(GLOB absl_LIBRARIES ${absl_LIB_DIR}/libabsl_*.so.*)
file(GLOB exclude_absl_LIBRARIES ${absl_LIB_DIR}/libabsl_*test*.so.*)

foreach (exclude_absl_LIBRARY ${exclude_absl_LIBRARIES})
    list(REMOVE_ITEM absl_LIBRARIES ${exclude_absl_LIBRARY})
endforeach ()


add_executable(main main.cpp)

# THIS WILL CAUSE SEGMENTATION FAULT
target_link_libraries(main
    PUBLIC ${TORCH_LIBRARIES}
    PUBLIC ${absl_LIBRARIES}
    PUBLIC CUDA::cupti
)


# # THIS WILL NOT CAUSE SEGMENTATION FAULT
# target_link_libraries(main
#     PUBLIC ${absl_LIBRARIES}
#     PUBLIC ${TORCH_LIBRARIES}
#     PUBLIC CUDA::cupti
# )

Then the main.cpp:

#include <cuda_runtime_api.h>
#include <torch/torch.h>
#include <iostream>

int main() {
    std::cout << "hello!" << std::endl;
    return 0;
}

Then execute the commands:

mkdir build
cd build
cmake ..
make
./main   <=== segmentation fault!

Interestingly, if you switch the order of TORCH_LIBRARIES and absl_LIBRARIES, the segmentation fault disappears.