Export tool config and target files for each relevant module

CMake will now generate config and target files for each module that
provides tools. As a result, namespaced global targets such as
Qt5::moc or Qt5::rcc can be made available.

Third party projects that require just these tools, and not the Qt
modules themselves,  should specify CMAKE_PREFIX_PATH pointing to the
installed Qt location, and call find_package(Qt5CoreTools),
find_package(Qt5GuiTools), etc.

It is also possible to call
find_package(Qt5Tools REQUIRED Core Widgets) where the last option
is a list of modules whose tools should be imported.

Note that all the tools are in the Qt5::
namespace and not in the Qt5CoreTools:: or Qt5WidgetsTools::
namespace.

This commit also changes the behavior regarding when to build tools
while building Qt itself.

When cross compiling Qt (checked via CMAKE_CROSSCOMPILING) or when
-DQT_FORCE_FIND_TOOLS=TRUE is passed, tools added by add_qt_tool will
always be searched for and not built.
In this case the user has to specify the CMake variable QT_HOST_PATH
pointing to an installed host Qt location.

When not cross compiling, tools added by add_qt_tool are built from
source.

When building leaf modules (like qtsvg) that require some tool that was
built in qtbase (like moc), the module project should contain a
find_package(Qt5ToolsCore) call and specify an appropriate
CMAKE_PREFIX_PATH so that the tool package is found.

Note that because HOST_QT_TOOLS_DIRECTORY was replaced by QT_HOST_PATH,
the ensure syncqt code was changed to make it work properly with
both qtbase and qtsvg.

Here's a list of tools and their module associations:
qmake, moc, rcc, tracegen, qfloat16-tables, qlalr  -> CoreTools
qvkgen -> GuiTools
uic -> WidgetTools
dbus related tools -> DBusTools

Task-number: QTBUG-74134
Change-Id: Ie67d1e2f8de46102b48eca008f0b50caf4fbe3ed
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

1 files changed, 18 insertions, 0 deletions

diff --git a/cmake/QtBaseGlobalTargets.cmake b/cmake/QtBaseGlobalTargets.cmake
index 73deb51b49..613dc49242 100644
--- a/cmake/QtBaseGlobalTargets.cmake
+++ b/cmake/QtBaseGlobalTargets.cmake
@@ -11,6 +11,7 @@ target_include_directories(Platform
 target_compile_definitions(Platform INTERFACE ${QT_PLATFORM_DEFINITIONS})
 set(config_install_dir "${INSTALL_LIBDIR}/cmake/${INSTALL_CMAKE_NAMESPACE}")
 
+# Generate and install Qt5 config file.
 configure_package_config_file(
     "${PROJECT_SOURCE_DIR}/cmake/QtConfig.cmake.in"
     "${CMAKE_CURRENT_BINARY_DIR}/${INSTALL_CMAKE_NAMESPACE}Config.cmake"
@@ -28,6 +29,23 @@ install(FILES
     COMPONENT Devel
 )
 
+# Generate and install Qt5Tools config file.
+configure_package_config_file(
+    "${PROJECT_SOURCE_DIR}/cmake/QtToolsConfig.cmake.in"
+    "${CMAKE_CURRENT_BINARY_DIR}/${INSTALL_CMAKE_NAMESPACE}ToolsConfig.cmake"
+    INSTALL_DESTINATION "${config_install_dir}"
+)
+write_basic_package_version_file(
+    ${CMAKE_CURRENT_BINARY_DIR}/${INSTALL_CMAKE_NAMESPACE}ToolsConfigVersion.cmake
+    VERSION ${PROJECT_VERSION}
+    COMPATIBILITY AnyNewerVersion
+)
+install(FILES
+    "${CMAKE_CURRENT_BINARY_DIR}/${INSTALL_CMAKE_NAMESPACE}ToolsConfig.cmake"
+    "${CMAKE_CURRENT_BINARY_DIR}/${INSTALL_CMAKE_NAMESPACE}ToolsConfigVersion.cmake"
+    DESTINATION "${config_install_dir}Tools"
+    COMPONENT Devel
+)
 
 ## Library to hold global features:
 ## These features are stored and accessed via Qt::GlobalConfig, but the