target_link_options are placed by CMake at the beginning of a linker
line. This gives us an opportunity to use the function to propagate
object libraries. This change adds one more check in the root
Config.cmake file. If CMP0099 policy is enabled, CMake enables
propagating of the linking options when linking two static libraries
using the PRIVATE linking visibility, so we can rely on the correct
linking order and expect object libraries to be propagated.
Note that on the platforms where cmake version is higher than 3.16
Qt uses CMP0099 NEW in functions like qt_add_executable. This means
that at the moment of creating an executable target the TARGET_POLICY
genex will also be NEW, so we do not take into the account the user
defined CMP0099.
If the CMP0099 policy is not available for a certain CMake version
we skip the TARGET_POLICY check and simply disable propagation of
the object libraries using target_link_options for both user and Qt
libraries. This is applicable for the CMake versions 3.16 and less.
Linking approaches have the following priorities(from higher to lower)
after this change:
- target_link_libraries - works if link order matters not or CMake
version greater equal 3.21.
- target_link_options - works if CMP0099 is set to NEW by user or
if the CMake version is greater than or equal to 3.17 and an
executable is created using Qt functions.
- object library finalizer - works if CMake version is greater equal
3.19 or qt6_finalize_target is called explicitly.
- target_sources - is used when all the other approaches could not
be used.
Amends a1fd4f51ad
Amends 3329212815
Pick-to: 6.2
Change-Id: I14f88caeb04e357191c840abeab89b03e210b796
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Ensure that the finalizer approach of
__qt_internal_propagate_object_library considers $<LINK_ONLY:>
libraries when traversing the dependencies of a target.
The issue was discovered when using the Quick.Shapes QML module in a
static build. The module has both a backing library and a plugin.
The backing library has some resource objects associated with it.
When the targets are exported, the plugin INTERFACE_LINK_LIBRARIES
has a $<LINK_ONLY:QuickShapes> dependency.
This ensures that the library will be linked, but depending on which
linking approach in __qt_internal_propagate_object_library is used,
the resources might not be linked to the final executable.
The resources are linked correctly when using the
target_link_libraries approach, but not when using the finalizer or
target_sources approach.
This change fixes the finalizer approach, but the target_sources
approach is still broken.
Amends a1fd4f51ad
Pick-to: 6.2
Change-Id: Ifbb91a17d388c3dc4263e17ec0d3bd5627b57cb4
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Check if link order matters before use the object library finalizer.
Amends 5fb99e3860
Pick-to: 6.2
Change-Id: Ie996bc175ebea36ccda1bb2fe388ae3b7fcde395
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
The linking logic of object libraries should be reusable outside of the
resource context. This introduces a
__qt_internal_propagate_object_library function that prepares all the
necessary genexes to link and propagate the object library to the
end-point executable.
Rename resource object finalizer API to make the naming more generic
to object libraries of any kind.
Amends 5fb99e3860
Pick-to: 6.2
Task-number: QTBUG-93002
Task-number: QTBUG-94528
Change-Id: I69d0f34c0dadbd67232de91035aaa53af93d1fa1
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Remove target specific flags from static_link_order.
Move the check to the common config.tests folder.
Amends 5fb99e3860
Pick-to: 6.2
Task-number: QTBUG-93002
Task-number: QTBUG-94528
Change-Id: I1368075ec6bd1e743b2b89fd93143df38a278ec2
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
For user projects we run the static link order check once
'find_package(Qt6 ...)' is called.
If linker can resolve circular dependencies between static libraries
and object files we set the _qt_link_order_matters property of the
Qt::Platform target. This indicates the use of finalizers is not
required and we may rely on CMake-base propagation of resource
libraries and resource object files.
If linker could not resolve circular dependencies depending on
the _qt_resource_objects_finalizer_mode value:
- Finalizer will be called and collected resource objects will be
linked to the target directly.
- Finalizer will be omitted and resource objects will be linked
using the target_sources function implicitly. This only
propagates resource one level up if consumer links the static
library PUBLICly, but all symbols will be resolved correctly
since object files are placed in the beginning of the linker line.
In the CMake version 3.21 we expect that CMake will take care about
the order of the resource object files in a linker line, it's
expected that all object files are located at the beginning of the
linker line.
TODO: Need to confirm that the CMake 3.21 meets the expectations.
Amends 4e901a2f99
Pick-to: 6.2
Task-number: QTBUG-93002
Task-number: QTBUG-94528
Change-Id: Ia68976df8182d3d3007b90c475c1e3928a305339
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
CMake 3.21 introduced a new IMPORTED_TARGETS directory property which
we can use to promote all imported targets within a scope to be
global.
This would cover transitive non-Qt imported targets which the Qt build
system does not know about and is thus a more complete solution
compared to promoting only Qt targets.
Run a finalizer at the end of the directory scope where
find_package(Qt6) is called to promote all imported targets within
that scope to global (when requested).
The old promotion method is disabled when the CMake version is new
enough.
Pick-to: 6.2
Task-number: QTBUG-92878
Task-number: QTBUG-94528
Change-Id: I533a3bd4186eba652f878ddd72c76118c2fd8bae
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
User projects can set the QT_PROMOTE_TO_GLOBAL_TARGETS variable to
true so that the various imported targets created by find_package(Qt6)
are promoted to global targets.
This would allow a project to find Qt packages in a subdirectory scope
while using those Qt targets from a different scope.
E.g. it fixes errors like
CMake Error at CMakeLists.txt:5 (target_link_libraries):
Error evaluating generator expression:
$<TARGET_OBJECTS:Qt6::Widgets_resources_1>
Objects of target "Qt6::Widgets_resources_1" referenced but no such
target exists.
when trying to use a static Qt from a sibling scope.
Various 3rd party dependency targets (like Atomic or ZLIB) are not
made global due to limitations in CMake, but as long as those targets
are not mentioned directly, it shouldn't cause issues.
The targets are made global in the generated
QtFooAdditionalTargetInfo.cmake file.
To ensure that resource object libraries promoted, the generation
of the file has to be done at the end of the defining scope
where qt_internal_export_additional_targets_file is called,
which is achieved with a deferred finalizer.
Replaced all occurrences of target promotion with a helper function
which allows tracing of all promoted targets by specifying
--log-level=debug to CMake.
Pick-to: 6.2
Fixes: QTBUG-92878
Change-Id: Ic4ec03b0bc383d7e591a58c520c3974fbea746d2
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
Resource objects might be linked to plugins. Since some plugins may
be present in LINK_LIBRARIES as the complex genexes, need to collect
them explicitly and iterate over plugin targets to find resource object
libraries that need to be exposed to end-point target executable.
Amends a1fd4f51ad
Change-Id: Icd85f54f7bf9d1b7e3382caa5d9aa62449b6adb8
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Avoid getting the LINK_LIBRARY property of the interface libraries
when calling a resource object finalizer.
Amends a1fd4f51ad
Change-Id: I19d625a927c66994902f5c89e6c82183c94af91e
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
In the previous implementation of the resource object finalizer, we
used the name of the resource object library without namespaces when
recording it in the resource libraries list. This causes an issue when
we or users export resource targets.
This approach marks resource object libraries with the exporting
property instead of collecting resource targets when creating them.
Amends 19e789bace
Change-Id: I8596815921f2c681ddd78d9b2e9a4e1cafe5000b
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
This proposal collects all the resource objects to the qt-specific
property of the static libraries. This is done to avoid littering
of other static libraries and put resource object files to the
source part of the linker line when linking the end-point
executable.
The way we link object resource libraries is changed back to the
target_link_libraries approach as we may omit using finalizers
with linkers other than ld. Users may enforce finalizers by calling
the qt6_enable_resource_objects_finalizer_mode function if need.
Refactor tests related to the static resources.
Amends ddaa7150d8
Task-number: QTBUG-93002
Change-Id: I74135e291cd82fb54d1b284b4b4a1e002b1fef98
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Needed for the upcoming static plugin mechanism, where we have to
extract the list of Qt module dependencies of a target and then extract
the plugins associated with those modules.
To do that we need to recursively collect the dependencies of a given
target.
Rename the moved functions to contain the __qt_internal prefix.
Also rename the existing QtPublicTargetsHelpers.cmake into
QtPlatformTargetHelpers.cmake to avoid confusion with the newly
introduced QtPublicTargetHelpers.cmake.
Task-number: QTBUG-92933
Change-Id: I48b5b6a8718a3424f59ca60f11fc9e97a809765d
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
