Use RPATH instead of RUNPATH to load libc++abi.so directly in Python.…

… No need to find and load explicitly.

Use libc++11 to build in Ubuntu 22.04. Warn if newer version is used.

TODO: Solution for Ubuntu 24.04

3rdparty/find_dependencies.cmake

@@ -1338,6 +1338,7 @@ if(BUILD_GUI)
  if (CPP_LIBRARY AND CPPABI_LIBRARY)
  set(CLANG_LIBDIR ${llvm_lib_dir})
  message(STATUS "CLANG_LIBDIR found in ubuntu-default: ${CLANG_LIBDIR}")
+ set(LIBCPP_VERSION ${llvm_ver})
  break()
  endif()
  endforeach()
@@ -1363,6 +1364,8 @@ if(BUILD_GUI)
  llvm-7/lib
  )
  get_filename_component(CLANG_LIBDIR ${CPPABI_LIBRARY} DIRECTORY)
+ string(REGEX MATCH "llvm-([0-9]+)/lib" _ ${CLANG_LIBDIR})
+ set(LIBCPP_VERSION ${CMAKE_MATCH_1})
  endif()
 
  # Find clang libraries at the exact path ${CLANG_LIBDIR}.
@@ -1378,6 +1381,11 @@ if(BUILD_GUI)
  target_link_libraries(3rdparty_filament INTERFACE -lstdc++
  ${CPP_LIBRARY} ${CPPABI_LIBRARY})
  message(STATUS "Filament C++ libraries: ${CPP_LIBRARY} ${CPPABI_LIBRARY}")
+ if (LIBCPP_VERSION GREATER 11)
+ message(WARNING "libc++ (LLVM) version ${LIBCPP_VERSION} > 11 includes libunwind that " 
+ "interferes with the system libunwind.so.8 and may crash Python code when exceptions "
+ "are used. Please consider using libc++ v11.")
+ endif()
  endif()
  if (APPLE)
  find_library(CORE_VIDEO CoreVideo)

cpp/pybind/CMakeLists.txt

@@ -80,6 +80,9 @@ set(PYTHON_COMPILED_MODULE_DIR
 if (APPLE)
  set_target_properties(pybind PROPERTIES BUILD_RPATH "@loader_path;@loader_path/..")
 elseif (UNIX)
+ # Use RPATH instead of RUNPATH in pybind so that needed libc++.so can find child dependant libc++abi.so in RPATH
+ # https://stackoverflow.com/questions/69662319/managing-secondary-dependencies-of-shared-libraries
+ target_link_options(pybind PRIVATE "LINKER:--disable-new-dtags")
  set_target_properties(pybind PROPERTIES BUILD_RPATH "$ORIGIN;$ORIGIN/..")
 endif()
 set_target_properties(pybind PROPERTIES

python/open3d/__init__.py

@@ -45,14 +45,6 @@ def load_cdll(path):
 if sys.platform == "win32": # Unix: Use rpath to find libraries
  _win32_dll_dir = os.add_dll_directory(str(Path(__file__).parent))
 
-if _build_config["BUILD_GUI"] and not (find_library("c++abi") or
- find_library("c++")):
- try: # Preload libc++.so and libc++abi.so (required by filament)
- load_cdll(str(next((Path(__file__).parent).glob("*c++abi.*"))))
- load_cdll(str(next((Path(__file__).parent).glob("*c++.*"))))
- except StopIteration: # Not found: check system paths while loading
- pass
-
 __DEVICE_API__ = "cpu"
 if _build_config["BUILD_CUDA_MODULE"]:
  # Load CPU pybind dll gracefully without introducing new python variable.

util/install_deps_ubuntu.sh

@@ -40,12 +40,19 @@ eval $(
  echo DISTRIB_RELEASE="$DISTRIB_RELEASE"
 )
 if [ "$DISTRIB_ID" == "Ubuntu" -a "$DISTRIB_RELEASE" == "20.04" ]; then
- # Ubuntu 20.04's clang/libc++-dev/libc++abi-dev are version 8, 10 or 12.
- # To avoid dependence on libunwind, we don't want to use versions later than 10.
+ # To avoid dependence on libunwind, we don't want to use clang / libc++ versions later than 11.
+ # Ubuntu 20.04's has versions 8, 10 or 12 while Ubuntu 22.04 has versions 11 and later.
  deps=("${deps[@]/clang/clang-10}")
  deps=("${deps[@]/libc++-dev/libc++-10-dev}")
  deps=("${deps[@]/libc++abi-dev/libc++abi-10-dev}")
 fi
+if [ "$DISTRIB_ID" == "Ubuntu" -a "$DISTRIB_RELEASE" == "22.04" ]; then
+ # To avoid dependence on libunwind, we don't want to use clang / libc++ versions later than 11.
+ # Ubuntu 20.04's has versions 8, 10 or 12 while Ubuntu 22.04 has versions 11 and later.
+ deps=("${deps[@]/clang/clang-11}")
+ deps=("${deps[@]/libc++-dev/libc++-11-dev}")
+ deps=("${deps[@]/libc++abi-dev/libc++abi-11-dev}")
+fi
 
 # Special case for ARM64
 if [ "$(uname -m)" == "aarch64" ]; then