[aot] Clean up exported symbols for libtaichi_c_api.so

.github/workflows/scripts/aot-demo.sh

@@ -165,4 +165,26 @@ function build-and-test-headless-demo-desktop {
     python3 ci/run_tests.py -l $TAICHI_C_API_INSTALL_DIR
 }
 
+function check-c-api-export-symbols {
+    cd taichi
+    TAICHI_REPO_DIR=$(pwd)
+    TAICHI_C_API_DIR=$(find $TAICHI_REPO_DIR -name libtaichi_c_api.* | head -n 1)
+
+    # T: global functions
+    # B: global variables (uninitialized)
+    # D: global variables (initialized)
+    EXPORT_SYM=" T \| B \| D "
+
+    # Note: this has to be consistent with the version scripts (export_symbol_linux.ld, export_symbol_mac.ld)
+    CAPI_SYM=" _\?ti_"
+    CAPI_UTILS_SYM=" capi::utils::"
+
+    NUM_LEAK_SYM=$(nm -C --extern-only ${TAICHI_C_API_DIR} | grep "${EXPORT_SYM}" | grep -v "${CAPI_SYM}" | grep -v "${CAPI_UTILS_SYM}" | wc -l)
+    if [ ${NUM_LEAK_SYM} -gt 0 ]; then
+        echo "Following symbols leaked from libtaichi_c_api: "
+        nm -C --extern-only ${TAICHI_C_API_DIR} | grep "${EXPORT_SYM}" | grep -v "${CAPI_SYM}" | grep -v "${CAPI_UTILS_SYM}"
+        exit 1
+    fi
+}
+
 $1

.github/workflows/testing.yml

@@ -216,6 +216,15 @@ jobs:
             -DTI_BUILD_TESTS:BOOL=ON
             -DTI_WITH_C_API=ON
 
+      - name: Check C-API Export Symbols
+        run: |
+          [[ ${{needs.check_files.outputs.run_job}} == false ]] && exit 0
+          . .github/workflows/scripts/common-utils.sh
+
+          ci-docker-run-gpu --name taichi-test-check-c-api-export-symbols \
+            registry.taichigraphics.com/taichidev-ubuntu18.04:v0.3.4 \
+            /home/dev/taichi/.github/workflows/scripts/aot-demo.sh check-c-api-export-symbols
+
       - name: Test
         id: test
         run: |
@@ -359,6 +368,13 @@ jobs:
             -DTI_WITH_BACKTRACE:BOOL=ON
             -DTI_WITH_C_API=ON
 
+      - name: Check C-API Export Symbols
+        run: |
+          [[ ${{needs.check_files.outputs.run_job}} == false ]] && exit 0
+          . .github/workflows/scripts/common-utils.sh
+
+          .github/workflows/scripts/aot-demo.sh check-c-api-export-symbols
+
       - name: Test
         id: test
         run: |

c_api/version_scripts/README.md

@@ -0,0 +1,5 @@
+Taichi C-API uses version script to control symbol exports from the shared library (https://github.com/taichi-dev/taichi/issues/6722)
+
+Note that the two version scripts export_symbols_linux.ld and export_symbols_mac.ld should have consistent contents otherwise will cause symbols mismatch on different platforms.
+
+CI will check for symbol leakage automatically, the regular expression rule of which should also stay consistent with the version scripts. CI scripts can be found at "check-c-api-export-symbols" function in .github/workflows/scripts/aot-demo.sh

c_api/version_scripts/export_symbols_linux.lds

@@ -0,0 +1,8 @@
+LIB_C_API_1.0 {
+  global: # specify symbols to be export from libtaichi_c_api
+    ti_*; # CAPI interface starts with "ti_*"
+    _ZN4capi5utils*; # matches "capi::utils::*" for CAPI tests
+
+  local:
+    *; # all other symbols will be convert to local bind type whatsoever
+};

c_api/version_scripts/export_symbols_mac.lds

@@ -0,0 +1,2 @@
+_ti_*
+__ZN4capi5utils*

cmake/TaichiCAPI.cmake

@@ -36,6 +36,15 @@ target_link_libraries(${TAICHI_C_API_NAME} PRIVATE taichi_ui_vulkan)
 target_link_libraries(${TAICHI_C_API_NAME} PRIVATE taichi_ui)
 endif()
 
+# Avoid exporting third party symbols from libtaichi_c_api.so
+# Note that on Windows, external symbols will be excluded from .dll automatically, by default.
+if(LINUX)
+    target_link_options(${TAICHI_C_API_NAME} PRIVATE -Wl,--version-script,${CMAKE_CURRENT_SOURCE_DIR}/c_api/version_scripts/export_symbols_linux.lds)
+elseif(APPLE)
+    # Unfortunately, ld on MacOS does not support --exclude-libs and we have to manually specify the exported symbols
+    target_link_options(${TAICHI_C_API_NAME} PRIVATE -Wl,-exported_symbols_list,${CMAKE_CURRENT_SOURCE_DIR}/c_api/version_scripts/export_symbols_mac.lds)
+endif()
+
 set(C_API_OUTPUT_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/build")
 set_target_properties(${TAICHI_C_API_NAME} PROPERTIES
     LIBRARY_OUTPUT_DIRECTORY ${C_API_OUTPUT_DIRECTORY}

cmake/TaichiCAPITests.cmake

@@ -24,6 +24,7 @@ if (WIN32)
     set_target_properties(${C_API_TESTS_NAME} PROPERTIES RUNTIME_OUTPUT_DIRECTORY_RELWITHDEBINFO ${C_API_TESTS_OUTPUT_DIR})
 endif()
 target_link_libraries(${C_API_TESTS_NAME} PRIVATE taichi_c_api)
+target_link_libraries(${C_API_TESTS_NAME} PRIVATE taichi_common)
 target_link_libraries(${C_API_TESTS_NAME} PRIVATE gtest_main)
 
 if (TI_WITH_BACKTRACE)

cmake/TaichiTests.cmake

@@ -59,6 +59,7 @@ if (WIN32)
 endif()
 target_link_libraries(${TESTS_NAME} PRIVATE taichi_core)
 target_link_libraries(${TESTS_NAME} PRIVATE gtest_main)
+target_link_libraries(${TESTS_NAME} PRIVATE taichi_common)
 
 if (TI_WITH_BACKTRACE)
     target_link_libraries(${TESTS_NAME} PRIVATE ${BACKWARD_ENABLE})