External/yaml-cpp
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Hide most of non-public symbols by default (#984)

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* Export YAML::detail::node::m_amount

The internal header node/detail/node.h is included by public headers;
YAML::detail::node is implemented in the header itself, and thus it gets
inlined... except for its static m_amount class member, which is
instantiated in the library only. Right now all the symbols of yaml-cpp
are exported (nothing is hidden), so the linker will find node::m_amount
in the yaml-cpp library.

As solution/workaround, explicitly export YAML::detail::node::m_amount.

* CMake: use GenerateExportHeader

Make use of the GenerateExportHeader CMake module to generate the dll.h
header with export macros.

While the produced dll.h is different, the result should be the same,
i.e. nothing changes for yaml-cpp or its users.

* CMake: hide all the symbols by default

Hide all the symbols that are not explicitly exported with YAML_CPP_API.
This way the ABI will be way smaller, and only actually exposing the
public classes/functions.
This commit is contained in:
Pino Toscano 2021-09-25 19:10:58 +02:00 committed by GitHub
parent 6308112e54
commit da1c8d360e
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 16 additions and 34 deletions
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15
CMakeLists.txt
View File

@ -14,6 +14,11 @@ include(CMakeDependentOption)
include(CheckCXXCompilerFlag)
include(GNUInstallDirs)
include(CTest)
include(GenerateExportHeader)
set(CMAKE_C_VISIBILITY_PRESET hidden)
set(CMAKE_CXX_VISIBILITY_PRESET hidden)
set(CMAKE_VISIBILITY_INLINES_HIDDEN 1)
find_program(YAML_CPP_CLANG_FORMAT_EXE NAMES clang-format)
@ -81,6 +86,7 @@ set_property(TARGET yaml-cpp
target_include_directories(yaml-cpp
PUBLIC
$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
$<BUILD_INTERFACE:${PROJECT_BINARY_DIR}/include>
$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
PRIVATE
$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/src>)
@ -136,6 +142,12 @@ write_basic_package_version_file(
"${PROJECT_BINARY_DIR}/yaml-cpp-config-version.cmake"
COMPATIBILITY AnyNewerVersion)
generate_export_header(yaml-cpp
BASE_NAME YAML_CPP
EXPORT_FILE_NAME "${PROJECT_BINARY_DIR}/include/yaml-cpp/dll.h"
EXPORT_MACRO_NAME YAML_CPP_API
)
configure_file(yaml-cpp.pc.in yaml-cpp.pc @ONLY)
if (YAML_CPP_INSTALL)
@ -145,6 +157,9 @@ if (YAML_CPP_INSTALL)
LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
install(DIRECTORY ${PROJECT_SOURCE_DIR}/include/
DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
FILES_MATCHING PATTERN "*.h")
install(DIRECTORY ${PROJECT_BINARY_DIR}/include/
DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
FILES_MATCHING PATTERN "*.h")
install(EXPORT yaml-cpp-targets

33
include/yaml-cpp/dll.h
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@ -1,33 +0,0 @@
#ifndef DLL_H_62B23520_7C8E_11DE_8A39_0800200C9A66
#define DLL_H_62B23520_7C8E_11DE_8A39_0800200C9A66
#if defined(_MSC_VER) || \
(defined(__GNUC__) && (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || \
(__GNUC__ >= 4)) // GCC supports "pragma once" correctly since 3.4
#pragma once
#endif
// The following ifdef block is the standard way of creating macros which make
// exporting from a DLL simpler. All files within this DLL are compiled with the
// yaml_cpp_EXPORTS symbol defined on the command line. This symbol should not
// be defined on any project that uses this DLL. This way any other project
// whose source files include this file see YAML_CPP_API functions as being
// imported from a DLL, whereas this DLL sees symbols defined with this macro as
// being exported.
#undef YAML_CPP_API
#ifdef YAML_CPP_DLL // Using or Building YAML-CPP DLL (definition defined
// manually)
#ifdef yaml_cpp_EXPORTS // Building YAML-CPP DLL (definition created by CMake
// or defined manually)
// #pragma message( "Defining YAML_CPP_API for DLL export" )
#define YAML_CPP_API __declspec(dllexport)
#else // yaml_cpp_EXPORTS
// #pragma message( "Defining YAML_CPP_API for DLL import" )
#define YAML_CPP_API __declspec(dllimport)
#endif // yaml_cpp_EXPORTS
#else // YAML_CPP_DLL
#define YAML_CPP_API
#endif // YAML_CPP_DLL
#endif // DLL_H_62B23520_7C8E_11DE_8A39_0800200C9A66

2
src/node_data.cpp
View File

@ -13,7 +13,7 @@
namespace YAML {
namespace detail {
std::atomic<size_t> node::m_amount{0};
YAML_CPP_API std::atomic<size_t> node::m_amount{0};
const std::string& node_data::empty_scalar() {
static const std::string svalue;