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curl/CMake/CurlSymbolHiding.cmake
Jakub Zakrzewski 6140dfcf3e 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
2016-09-10 00:35:38 +02:00

62 lines
2.7 KiB
CMake

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 <stdio.h>
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})