Merge pull request #1314 from domcharrier/fix/hide-non-api-symbols-gcc-clang

[FIX] Hide non-API symbols when CXX compiler supports GNUC style visibility controls to prevent LLVM symbol export and interposition

Author: esc

ffi/CMakeLists.txt

@@ -13,6 +13,11 @@ include(GNUInstallDirs)
 
 set(CMAKE_CXX_STANDARD 17)
 
+# Preset function visibility to hidden, API functions
+# are annotated explicitly to use 'default' visibility.
+set(CMAKE_CXX_VISIBILITY_PRESET "hidden")
+set(CMAKE_C_VISIBILITY_PRESET "hidden")
+
 find_package(LLVM REQUIRED CONFIG)
 
 message(STATUS "Found LLVM ${LLVM_PACKAGE_VERSION}")
@@ -316,7 +321,6 @@ endif()
 message(STATUS "LLVM target link libraries: ${llvm_libs}")
 target_link_libraries(llvmlite ${llvm_libs})
 
-
 # -flto and --exclude-libs allow removal of unused parts of LLVM
 # TODO: these options are just set, they should really be tested for
 # suitability.
@@ -328,6 +332,12 @@ if(UNIX AND NOT APPLE)
     if (LLVMLITE_FLTO)
         STRING(APPEND FORCED_LINK_FLAGS " -flto")
     endif()
+    if(NOT LLVMLITE_SHARED)
+        # If LLVM is statically linked, we specify -Bsymbolic to prevent
+        # that LLVM symbols can be interposed upon by previously
+        # loaded shared objects that export LLVM symbols.
+        STRING(APPEND FORCED_LINK_FLAGS " -Wl,-Bsymbolic")
+    endif()
     set_property(TARGET llvmlite APPEND_STRING PROPERTY LINK_FLAGS
                  "${FORCED_LINK_FLAGS}")
 elseif(APPLE)

ffi/core.h

@@ -17,7 +17,8 @@
 #if defined(HAVE_DECLSPEC_DLL)
 #define API_EXPORT(RTYPE) __declspec(dllexport) RTYPE
 #else
-#define API_EXPORT(RTYPE) RTYPE
+// Non-windows: use visibility attributes.
+#define API_EXPORT(RTYPE) __attribute__((visibility("default"))) RTYPE
 #endif
 
 extern "C" {