From 6140dfcf3e7845f11dee755de6865379aa96dab7 Mon Sep 17 00:00:00 2001 From: Jakub Zakrzewski Date: Sun, 4 Sep 2016 12:37:46 +0200 Subject: [PATCH] CMake: Try to (un-)hide private library symbols Detect support for compiler symbol visibility flags and apply those according to CURL_HIDDEN_SYMBOLS option. It should work true to the autotools build except it tries to unhide symbols on Windows when requested and prints warning if it fails. Ref: https://github.com/curl/curl/issues/981#issuecomment-242665951 Reported-by: Daniel Stenberg --- CMake/CurlSymbolHiding.cmake | 61 ++++++++++++++++++++++++++++++++++++ CMakeLists.txt | 3 +- lib/CMakeLists.txt | 5 +++ lib/curl_config.h.cmake | 2 +- tests/libtest/CMakeLists.txt | 4 +++ 5 files changed, 72 insertions(+), 3 deletions(-) create mode 100644 CMake/CurlSymbolHiding.cmake diff --git a/CMake/CurlSymbolHiding.cmake b/CMake/CurlSymbolHiding.cmake new file mode 100644 index 000000000..9f7d29633 --- /dev/null +++ b/CMake/CurlSymbolHiding.cmake @@ -0,0 +1,61 @@ +include(CheckCSourceCompiles) + +option(CURL_HIDDEN_SYMBOLS "Set to ON to hide libcurl internal symbols (=hide all symbols that aren't officially external)." ON) +mark_as_advanced(CURL_HIDDEN_SYMBOLS) + +if(CURL_HIDDEN_SYMBOLS) + set(SUPPORTS_SYMBOL_HIDING FALSE) + + if(CMAKE_C_COMPILER_ID MATCHES "Clang") + set(SUPPORTS_SYMBOL_HIDING TRUE) + set(_SYMBOL_EXTERN "__attribute__ ((__visibility__ (\"default\")))") + set(_CFLAG_SYMBOLS_HIDE "-fvisibility=hidden") + elseif(CMAKE_COMPILER_IS_GNUCC) + if(NOT CMAKE_VERSION VERSION_LESS 2.8.10) + set(GCC_VERSION ${CMAKE_C_COMPILER_VERSION}) + else() + execute_process(COMMAND ${CMAKE_C_COMPILER} -dumpversion + OUTPUT_VARIABLE GCC_VERSION) + endif() + if(NOT GCC_VERSION VERSION_LESS 3.4) + # note: this is considered buggy prior to 4.0 but the autotools don't care, so let's ignore that fact + set(SUPPORTS_SYMBOL_HIDING TRUE) + set(_SYMBOL_EXTERN "__attribute__ ((__visibility__ (\"default\")))") + set(_CFLAG_SYMBOLS_HIDE "-fvisibility=hidden") + endif() + elseif(CMAKE_C_COMPILER_ID MATCHES "SunPro" AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 8.0) + set(SUPPORTS_SYMBOL_HIDING TRUE) + set(_SYMBOL_EXTERN "__global") + set(_CFLAG_SYMBOLS_HIDE "-xldscope=hidden") + elseif(CMAKE_C_COMPILER_ID MATCHES "Intel" AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 9.0) + # note: this should probably just check for version 9.1.045 but I'm not 100% sure + # so let's to it the same way autotools do. + set(SUPPORTS_SYMBOL_HIDING TRUE) + set(_SYMBOL_EXTERN "__attribute__ ((__visibility__ (\"default\")))") + set(_CFLAG_SYMBOLS_HIDE "-fvisibility=hidden") + check_c_source_compiles("#include + int main (void) { printf(\"icc fvisibility bug test\"); return 0; }" _no_bug) + if(NOT _no_bug) + set(SUPPORTS_SYMBOL_HIDING FALSE) + set(_SYMBOL_EXTERN "") + set(_CFLAG_SYMBOLS_HIDE "") + endif() + elseif(MSVC) + set(SUPPORTS_SYMBOL_HIDING TRUE) + endif() + + set(HIDES_CURL_PRIVATE_SYMBOLS ${SUPPORTS_SYMBOL_HIDING}) +elseif(MSVC) + if(NOT CMAKE_VERSION VERSION_LESS 3.7) + set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS TRUE) #present since 3.4.3 but broken + set(HIDES_CURL_PRIVATE_SYMBOLS FALSE) + else() + message(WARNING "Hiding private symbols regardless CURL_HIDDEN_SYMBOLS being disabled.") + set(HIDES_CURL_PRIVATE_SYMBOLS TRUE) + endif() +elseif() + set(HIDES_CURL_PRIVATE_SYMBOLS FALSE) +endif() + +set(CURL_CFLAG_SYMBOLS_HIDE ${_CFLAG_SYMBOLS_HIDE}) +set(CURL_EXTERN_SYMBOL ${_SYMBOL_EXTERN}) diff --git a/CMakeLists.txt b/CMakeLists.txt index 7113c7ea2..4571cdb9f 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -119,8 +119,7 @@ if(MSVC) mark_as_advanced(BUILD_RELEASE_DEBUG_DIRS) endif() -option(CURL_HIDDEN_SYMBOLS "Set to ON to hide libcurl internal symbols (=hide all symbols that aren't officially external)." ON) -mark_as_advanced(CURL_HIDDEN_SYMBOLS) +include(CurlSymbolHiding) option(HTTP_ONLY "disables all protocols except HTTP (This overrides all CURL_DISABLE_* options)" OFF) mark_as_advanced(HTTP_ONLY) diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt index 49a340938..eb2de6d87 100644 --- a/lib/CMakeLists.txt +++ b/lib/CMakeLists.txt @@ -87,6 +87,11 @@ endif() set_target_properties(${LIB_NAME} PROPERTIES COMPILE_DEFINITIONS BUILDING_LIBCURL) +if(HIDES_CURL_PRIVATE_SYMBOLS) + set_property(TARGET ${LIB_NAME} APPEND PROPERTY COMPILE_DEFINITIONS "CURL_HIDDEN_SYMBOLS") + set_property(TARGET ${LIB_NAME} APPEND PROPERTY COMPILE_FLAGS ${CURL_CFLAG_SYMBOLS_HIDE}) +endif() + # Remove the "lib" prefix since the library is already named "libcurl". set_target_properties(${LIB_NAME} PROPERTIES PREFIX "") set_target_properties(${LIB_NAME} PROPERTIES IMPORT_PREFIX "") diff --git a/lib/curl_config.h.cmake b/lib/curl_config.h.cmake index f7dbd23c0..ddcd210de 100644 --- a/lib/curl_config.h.cmake +++ b/lib/curl_config.h.cmake @@ -67,7 +67,7 @@ #cmakedefine CURL_DISABLE_VERBOSE_STRINGS 1 /* to make a symbol visible */ -#cmakedefine CURL_EXTERN_SYMBOL 1 +#cmakedefine CURL_EXTERN_SYMBOL ${CURL_EXTERN_SYMBOL} /* Ensure using CURL_EXTERN_SYMBOL is possible */ #ifndef CURL_EXTERN_SYMBOL #define CURL_EXTERN_SYMBOL diff --git a/tests/libtest/CMakeLists.txt b/tests/libtest/CMakeLists.txt index cc9d7e1f8..a7449c374 100644 --- a/tests/libtest/CMakeLists.txt +++ b/tests/libtest/CMakeLists.txt @@ -43,6 +43,10 @@ if(NOT WIN32) # library at (tests)/libtest/.libs/libhostname.so set_target_properties(hostname PROPERTIES LIBRARY_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/.libs) + if(HIDES_CURL_PRIVATE_SYMBOLS) + set_property(TARGET hostname APPEND PROPERTY COMPILE_DEFINITIONS "CURL_HIDDEN_SYMBOLS") + set_property(TARGET hostname APPEND PROPERTY COMPILE_FLAGS ${CURL_CFLAG_SYMBOLS_HIDE}) + endif() endif() # # files used only in some libcurl test programs