qt5base-lts/cmake/QtNoLinkTargetHelpers.cmake
Lucie Gérard 32df595275 Change the license of all CMakeLists.txt and *.cmake files to BSD
Task-number: QTBUG-105718
Change-Id: I5d3ef70a31235868b9be6cb479b7621bf2a8ba39
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Jörg Bornemann <joerg.bornemann@qt.io>
2022-08-23 23:58:42 +02:00

59 lines
3.1 KiB
CMake

# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: BSD-3-Clause
function(qt_create_nolink_target target dependee_target)
if(NOT TARGET "${target}")
message(FATAL_ERROR "${target} does not exist when trying to build a nolink target.")
endif()
get_target_property(type "${target}" TYPE)
if(type STREQUAL EXECUTABLE)
message(FATAL_ERROR "${target} must be a library of some kind.")
endif()
if(type STREQUAL OBJECT_LIBRARY)
message(FATAL_ERROR "${target} must not be an object library.")
endif()
# Strip off the namespace prefix, so from Vulkan::Vulkan to Vulkan, and then append _nolink.
string(REGEX REPLACE "^.*::" "" non_prefixed_target ${target})
set(nolink_target "${non_prefixed_target}_nolink")
# Create the nolink interface target, assign the properties from the original target,
# associate the nolink target with the same export which contains
# the target that uses the _nolink target.
# Also create a namespaced alias of the form ${target}::${target}_nolink which is used by
# our modules.
# Also create a Qt namespaced alias target, because when exporting via install(EXPORT)
# Vulkan::Vulkan_nolink transforms into Qt6::Vulkan_nolink, and the latter needs to be an
# accessible alias for standalone tests.
if(NOT TARGET "${nolink_target}")
add_library("${nolink_target}" INTERFACE)
set(prefixed_nolink_target "${target}_nolink")
# When configuring an example with qmake, if QtGui is built with Vulkan support but the
# user's machine where Qt is installed doesn't have Vulkan, qmake doesn't fail saying
# that vulkan is not installed. Instead it silently configures and just doesn't add
# the include headers.
# To mimic that in CMake, if the Vulkan CMake package is not found, we shouldn't fail
# at generation time saying that the Vulkan target does not exist. Instead check with a
# genex that the target exists to query the properties, otherwise just silently continue.
# FIXME: If we figure out that such behavior should only be applied to Vulkan, and not the
# other _nolink targets, we'll have to modify this to be configurable.
set(target_exists_genex "$<TARGET_EXISTS:${target}>")
set(props_to_set INTERFACE_INCLUDE_DIRECTORIES INTERFACE_SYSTEM_INCLUDE_DIRECTORIES
INTERFACE_COMPILE_DEFINITIONS INTERFACE_COMPILE_OPTIONS
INTERFACE_COMPILE_FEATURES)
foreach(prop ${props_to_set})
set_target_properties(
"${nolink_target}" PROPERTIES
${prop} $<${target_exists_genex}:$<TARGET_PROPERTY:${target},${prop}>>
)
endforeach()
add_library(${prefixed_nolink_target} ALIAS ${nolink_target})
add_library("${INSTALL_CMAKE_NAMESPACE}::${nolink_target}" ALIAS ${nolink_target})
set(export_name "${INSTALL_CMAKE_NAMESPACE}${dependee_target}Targets")
qt_install(TARGETS ${nolink_target} EXPORT ${export_name})
endif()
endfunction()