From 1bb4602af2194e1ce699f68de5056d7652db8e80 Mon Sep 17 00:00:00 2001
From: Sameer Sheorey <sameer.sheorey@intel.com>
Date: Sun, 29 Sep 2024 00:52:04 -0700
Subject: [PATCH] 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 |  8 ++++++++
 cpp/pybind/CMakeLists.txt        |  3 +++
 python/open3d/__init__.py        |  8 --------
 util/install_deps_ubuntu.sh      | 11 +++++++++--
 4 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/3rdparty/find_dependencies.cmake b/3rdparty/find_dependencies.cmake
index 77b7085df69..8d4cf9284ee 100644
--- a/3rdparty/find_dependencies.cmake
+++ b/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 ${LIBCPP_VERSION} > 11 includes libunwind that " 
+                "interferes with the system libunwind.so.8 and may crash Python code when exceptions "
+                "are used. Please consider using libc++ v11.")
+            endif()
         endif()
         if (APPLE)
             find_library(CORE_VIDEO CoreVideo)
diff --git a/cpp/pybind/CMakeLists.txt b/cpp/pybind/CMakeLists.txt
index e7a534a3eb3..c79bbd96719 100644
--- a/cpp/pybind/CMakeLists.txt
+++ b/cpp/pybind/CMakeLists.txt
@@ -80,6 +80,9 @@ set(PYTHON_COMPILED_MODULE_DIR
 if (APPLE)
     set_target_properties(pybind PROPERTIES BUILD_RPATH "@loader_path;@loader_path/..")
 elseif (UNIX)
+    # Use RPATH instead of RUNPATH in pybind so that needed libc++.so can find child dependant libc++abi.so in RPATH
+    # https://stackoverflow.com/questions/69662319/managing-secondary-dependencies-of-shared-libraries
+    target_link_options(pybind PRIVATE "LINKER:--disable-new-dtags")
     set_target_properties(pybind PROPERTIES BUILD_RPATH "$ORIGIN;$ORIGIN/..")
 endif()
 set_target_properties(pybind PROPERTIES
diff --git a/python/open3d/__init__.py b/python/open3d/__init__.py
index 141bf426c50..f7354b2a90c 100644
--- a/python/open3d/__init__.py
+++ b/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.
diff --git a/util/install_deps_ubuntu.sh b/util/install_deps_ubuntu.sh
index 3e359a1a6e7..f5cd661ab58 100755
--- a/util/install_deps_ubuntu.sh
+++ b/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