Implement generating of a module cpp export header

Add an option that automatically generates an export header for a Qt
module. The header contains only Q_DECL_EXPORT/Q_DECL_IMPORT related
content, so it's not a full replacement of 'global' header files.

Task-number: QTBUG-90492
Change-Id: I250d1201b11d4096b7e78e61cbf4565945fe6517
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

cmake/QtBaseGlobalTargets.cmake

@@ -235,6 +235,7 @@ qt_copy_or_install(FILES
                    cmake/QtWasmHelpers.cmake
                    cmake/QtWrapperScriptHelpers.cmake
                    cmake/QtWriteArgsFile.cmake
+                   cmake/modulecppexports.h.in
     DESTINATION "${__GlobalConfig_install_dir}"
 )
 

cmake/QtModuleHelpers.cmake

@@ -12,6 +12,7 @@ macro(qt_internal_get_internal_add_module_keywords option_args single_args multi
         NO_CONFIG_HEADER_FILE
         NO_ADDITIONAL_TARGET_INFO
         NO_GENERATE_METATYPES
+        GENERATE_CPP_EXPORTS # TODO: Rename to NO_GENERATE_CPP_EXPORTS once migration is done
         GENERATE_METATYPES          # TODO: Remove once it is not used anymore
     )
     set(${single_args}
@@ -20,6 +21,7 @@ macro(qt_internal_get_internal_add_module_keywords option_args single_args multi
         CONFIG_MODULE_NAME
         PRECOMPILED_HEADER
         CONFIGURE_FILE_PATH
+        CPP_EXPORT_HEADER_NAME
         ${__default_target_info_args}
     )
     set(${multi_args}
@@ -139,6 +141,22 @@ function(qt_internal_add_module target)
     string(REPLACE "-" "_" module_define_infix "${module_define_infix}")
     string(REPLACE "." "_" module_define_infix "${module_define_infix}")
 
+    if(arg_MODULE_INCLUDE_NAME)
+        set(module_include_name ${arg_MODULE_INCLUDE_NAME})
+    else()
+        set(module_include_name ${module})
+    endif()
+
+    if(arg_GENERATE_CPP_EXPORTS)
+        if(arg_CPP_EXPORT_HEADER_NAME)
+            set(cpp_export_header_name "CPP_EXPORT_HEADER_NAME;${arg_CPP_EXPORT_HEADER_NAME}")
+        endif()
+        qt_internal_generate_cpp_global_exports(${target} ${module_define_infix}
+            ${module_include_name}
+            "${cpp_export_header_name}"
+        )
+    endif()
+
     set(property_prefix "INTERFACE_")
     if(NOT arg_HEADER_MODULE)
         qt_set_common_target_properties(${target})
@@ -259,12 +277,6 @@ function(qt_internal_add_module target)
         endif()
     endif()
 
-    if(arg_MODULE_INCLUDE_NAME)
-        set(module_include_name ${arg_MODULE_INCLUDE_NAME})
-    else()
-        set(module_include_name ${module})
-    endif()
-
     # Module headers:
     set_property(TARGET "${target}" APPEND PROPERTY EXPORT_PROPERTIES _qt_module_has_headers)
     if(${arg_NO_MODULE_HEADERS} OR ${arg_NO_SYNC_QT})
@@ -796,3 +808,25 @@ function(qt_describe_module target)
 
     qt_install(FILES "${descfile_out}" DESTINATION "${install_dir}")
 endfunction()
+
+function(qt_internal_generate_cpp_global_exports target module_define_infix module_include_name)
+    cmake_parse_arguments(arg
+        ""
+        "CPP_EXPORT_HEADER_NAME"
+        "" ${ARGN})
+    qt_internal_module_info(module "${target}")
+    if(NOT arg_CPP_EXPORT_HEADER_NAME)
+        set(arg_CPP_EXPORT_HEADER_NAME "qt${module_lower}exports.h")
+    endif()
+
+    set(generated_header_path
+        "${QT_BUILD_DIR}/include/${module_include_name}/${arg_CPP_EXPORT_HEADER_NAME}"
+    )
+
+    configure_file("${QT_CMAKE_DIR}/modulecppexports.h.in"
+        "${generated_header_path}" @ONLY
+    )
+
+    target_sources(${target} PRIVATE "${generated_header_path}")
+    set_property(TARGET ${target} APPEND PROPERTY PUBLIC_HEADER "${generated_header_path}")
+endfunction()

cmake/modulecppexports.h.in

@@ -0,0 +1,55 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the @module@ module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QT@module_define_infix@EXPORTS_H
+#define QT@module_define_infix@EXPORTS_H
+
+#include <QtCore/qglobal.h>
+
+#if defined(QT_SHARED) || !defined(QT_STATIC)
+#  if defined(QT_BUILD_@module_define_infix@_LIB)
+#    define Q_@module_define_infix@_EXPORT Q_DECL_EXPORT
+#  else
+#    define Q_@module_define_infix@_EXPORT Q_DECL_IMPORT
+#  endif
+#else
+#  define Q_@module_define_infix@_EXPORT
+#endif
+
+#endif // QT@module_define_infix@EXPORTS_H

sync.profile

@@ -23,6 +23,8 @@
     "QtMockPlugins2" => "$basedir/tests/auto/cmake/mockplugins/mockplugins2",
     "QtMockPlugins3" => "$basedir/tests/auto/cmake/mockplugins/mockplugins3",
     "QtMockStaticResources1" => "$basedir/tests/auto/cmake/test_static_resources/mock_static_resources1",
+    "QtTestAutogeneratingCppExports" => "$basedir/tests/auto/cmake/test_generating_cpp_exports/test_autogenerating_cpp_exports",
+    "QtTestAutogeneratingCppExportsCustomName" => "$basedir/tests/auto/cmake/test_generating_cpp_exports/test_autogenerating_cpp_exports_custom_name",
 );
 %moduleheaders = ( # restrict the module headers to those found in relative path
     "QtEglFSDeviceIntegration" => "api",

tests/auto/cmake/CMakeLists.txt

@@ -261,3 +261,5 @@ _qt_internal_test_expect_pass(tst_qaddpreroutine
 _qt_internal_test_expect_pass(test_static_resources
                               BINARY "${CMAKE_CTEST_COMMAND}"
                               BINARY_ARGS "-V")
+
+_qt_internal_test_expect_pass(test_generating_cpp_exports)

tests/auto/cmake/test_generating_cpp_exports/.cmake.conf

@@ -0,0 +1 @@
+set(QT_REPO_MODULE_VERSION "6.2.0")

tests/auto/cmake/test_generating_cpp_exports/CMakeLists.txt

@@ -0,0 +1,19 @@
+cmake_minimum_required(VERSION 3.15.0)
+
+include(.cmake.conf)
+
+project(TestGeneratingCppExports
+        DESCRIPTION "Test of the generating of cpp exports"
+        HOMEPAGE_URL "https://qt.io/"
+        LANGUAGES CXX C
+        VERSION "${QT_REPO_MODULE_VERSION}"
+)
+
+find_package(Qt6 COMPONENTS Core BuildInternals Test CONFIG REQUIRED)
+
+qt_build_repo_begin()
+
+add_subdirectory(test_autogenerating_cpp_exports)
+add_subdirectory(test_autogenerating_cpp_exports_custom_name)
+
+qt_build_repo_end()

tests/auto/cmake/test_generating_cpp_exports/test_autogenerating_cpp_exports/CMakeLists.txt

@@ -0,0 +1,17 @@
+qt_internal_add_module(TestAutogeneratingCppExports
+    GENERATE_CPP_EXPORTS
+    SOURCES
+        module_api.h
+        module_api.cpp
+    PUBLIC_LIBRARIES
+        Qt::Core
+)
+
+qt_internal_extend_target(TestAutogeneratingCppExports
+    CONDITION GCC OR MINGW
+    COMPILE_OPTIONS
+        -fvisibility=hidden
+)
+
+add_executable(TestAutogeneratingCppExportsApp use_api.cpp)
+target_link_libraries(TestAutogeneratingCppExportsApp PRIVATE TestAutogeneratingCppExports)

tests/auto/cmake/test_generating_cpp_exports/test_autogenerating_cpp_exports/module_api.cpp

@@ -0,0 +1,45 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "module_api.h"
+
+void TestApi::dummy()
+{
+    // Do nothing
+}

tests/auto/cmake/test_generating_cpp_exports/test_autogenerating_cpp_exports/module_api.h

@@ -0,0 +1,51 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef MODULE_API_H
+#define MODULE_API_H
+
+#include <QtTestAutogeneratingCppExports/qttestautogeneratingcppexportsexports.h>
+
+struct Q_TESTAUTOGENERATINGCPPEXPORTS_EXPORT TestApi
+{
+    TestApi() = default;
+    void dummy();
+};
+
+#endif //MODULE_API_H

tests/auto/cmake/test_generating_cpp_exports/test_autogenerating_cpp_exports/use_api.cpp

@@ -0,0 +1,47 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "module_api.h"
+
+int main(int, char*[])
+{
+    TestApi api;
+    api.dummy();
+    return 0;
+}

tests/auto/cmake/test_generating_cpp_exports/test_autogenerating_cpp_exports_custom_name/CMakeLists.txt

@@ -0,0 +1,19 @@
+qt_internal_add_module(TestAutogeneratingCppExportsCustomName
+    GENERATE_CPP_EXPORTS
+    CPP_EXPORT_HEADER_NAME
+        "customname_exports.hpp"
+    SOURCES
+        module_api.h
+        module_api.cpp
+    PUBLIC_LIBRARIES
+        Qt::Core
+)
+
+qt_internal_extend_target(TestAutogeneratingCppExportsCustomName
+    CONDITION GCC OR MINGW
+    COMPILE_OPTIONS
+        -fvisibility=hidden
+)
+
+add_executable(testapp2 use_api.cpp)
+target_link_libraries(testapp2 PRIVATE TestAutogeneratingCppExportsCustomName)

tests/auto/cmake/test_generating_cpp_exports/test_autogenerating_cpp_exports_custom_name/module_api.cpp

@@ -0,0 +1,45 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "module_api.h"
+
+void TestApi::dummy()
+{
+    // Do nothing
+}

tests/auto/cmake/test_generating_cpp_exports/test_autogenerating_cpp_exports_custom_name/module_api.h

@@ -0,0 +1,51 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef MODULE_API_H
+#define MODULE_API_H
+
+#include <QtTestAutogeneratingCppExportsCustomName/customname_exports.hpp>
+
+struct Q_TESTAUTOGENERATINGCPPEXPORTSCUSTOMNAME_EXPORT TestApi
+{
+    TestApi() = default;
+    void dummy();
+};
+
+#endif //MODULE_API_H

tests/auto/cmake/test_generating_cpp_exports/test_autogenerating_cpp_exports_custom_name/use_api.cpp

@@ -0,0 +1,47 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "module_api.h"
+
+int main(int, char*[])
+{
+    TestApi api;
+    api.dummy();
+    return 0;
+}