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authorJakub Zakrzewski <slither.jz@gmail.com>2016-09-04 12:37:46 +0200
committerJakub Zakrzewski <slither.jz@gmail.com>2016-09-10 00:35:38 +0200
commit6140dfcf3e7845f11dee755de6865379aa96dab7 (patch)
treeb04e4001ee22651132fda45756d04105362514d1
parent83ef21e5e9946de2805ae10cc5e6ef9431b22702 (diff)
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
-rw-r--r--CMake/CurlSymbolHiding.cmake61
-rw-r--r--CMakeLists.txt3
-rw-r--r--lib/CMakeLists.txt5
-rw-r--r--lib/curl_config.h.cmake2
-rw-r--r--tests/libtest/CMakeLists.txt4
5 files changed, 72 insertions, 3 deletions
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 <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 ${_SYMBOL_EXTERN})
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7113c7ea2..4571cdb9f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -119,8 +119,7 @@ if(MSVC)
mark_as_advanced(BUILD_RELEASE_DEBUG_DIRS)
endif()
-option(CURL_HIDDEN_SYMBOLS "Set to ON to hide libcurl internal symbols (=hide all symbols that aren't officially external)." ON)
-mark_as_advanced(CURL_HIDDEN_SYMBOLS)
+include(CurlSymbolHiding)
option(HTTP_ONLY "disables all protocols except HTTP (This overrides all CURL_DISABLE_* options)" OFF)
mark_as_advanced(HTTP_ONLY)
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 49a340938..eb2de6d87 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -87,6 +87,11 @@ endif()
set_target_properties(${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