symbol-visibility

commit df9206778fe9ff1bdd56d975c29c43dfe1e66de7
Author: Christopher James Halse Rogers <christopher.halse.rogers@canonical.com>
Date:   Fri Nov 23 15:26:53 2018 +1100

    Export only YAML_CPP_API-tagged symbols on Linux.

    This marks classes tagged with YAML_CPP_API with visibility("default"), to
    explicitly export them, and then makes the default visibility "hidden" via
    -fvisibility=hidden.

    This reduces the number of exported symbols by more than 50%, which has
    a small application start-up time and memory useage benefit. It also
    makes it more feasible to audit the set of exported symbols in automated
    ABI compatibility systems.

Gbp-Pq: Name symbol-visibility.patch

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d2685e7116ce9ac9abe607258c5064668536c6c3..59ce2c749329ba62120d8ce128b1a2938b76a068 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -137,6 +137,14 @@ if(WIN32)
        endif()
 endif()
 
+if(CMAKE_SYSTEM_NAME MATCHES "Linux")
+       set(CMAKE_CXX_VISIBILITY_PRESET hidden)
+       if (POLICY CMP0063)
+               cmake_policy(SET CMP0063 NEW)
+       endif()
+       add_definitions(-DYAML_CPP_USE_VISIBILITY)
+endif()
+
 # GCC or Clang or Intel Compiler specialities
 if(CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR
    (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC") OR

diff --git a/include/yaml-cpp/dll.h b/include/yaml-cpp/dll.h
index a32c06b2e308aa0512137ba763ff5f7247ae1b18..5b8c9058ed69cd6ee0f2cb010eb28c2f7615c208 100644 (file)
--- a/include/yaml-cpp/dll.h
+++ b/include/yaml-cpp/dll.h
@@ -27,7 +27,11 @@
 #define YAML_CPP_API __declspec(dllimport)
 #endif  // yaml_cpp_EXPORTS
 #else   // YAML_CPP_DLL
+#ifdef YAML_CPP_USE_VISIBILITY
+#define YAML_CPP_API __attribute__ ((visibility("default")))
+#else
 #define YAML_CPP_API
+#endif // YAML_CPP_USE_VISIBILITY
 #endif  // YAML_CPP_DLL
 
 #endif  // DLL_H_62B23520_7C8E_11DE_8A39_0800200C9A66