Check the impact of static link order for user projects

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 4e901a2f99cbfda3b479253ea54b16f02e1c3aa5

Pick-to: 6.2
Task-number: QTBUG-93002
Task-number: QTBUG-94528
Change-Id: Ia68976df8182d3d3007b90c475c1e3928a305339
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

1 files changed, 13 insertions, 22 deletions

diff --git a/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake b/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake
index 1427f5a5fc..8cbd0b566f 100644
--- a/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake
+++ b/cmake/QtBuildInternals/QtBuildInternalsConfig.cmake
@@ -372,11 +372,6 @@ macro(qt_build_repo_begin)
     qt_build_internals_set_up_private_api()
     qt_enable_cmake_languages()
 
-    # QtBase has own call right after definition of internal platform-specific targets.
-    if(NOT PROJECT_NAME STREQUAL "QtBase")
-        qt_internal_run_common_config_tests()
-    endif()
-
     # Add global docs targets that will work both for per-repo builds, and super builds.
     if(NOT TARGET docs)
         add_custom_target(docs)
@@ -950,24 +945,20 @@ if ("STANDALONE_TEST" IN_LIST Qt6BuildInternals_FIND_COMPONENTS)
 endif()
 
 function(qt_internal_static_link_order_test)
-    if(TARGET ${QT_CMAKE_EXPORT_NAMESPACE}::PlatformCommonInternal)
-        get_target_property(linker_options
-            ${QT_CMAKE_EXPORT_NAMESPACE}::PlatformCommonInternal INTERFACE_LINK_OPTIONS
-        )
-        string(JOIN " " linker_options ${linker_options})
-    endif()
-
-    qt_config_compile_test(static_link_order
-        LABEL "Check if linker can resolve circular dependencies"
-        PROJECT_PATH "${QT_CMAKE_DIR}/config.tests/static_link_order"
-        CMAKE_FLAGS "-DCMAKE_EXE_LINKER_FLAGS:STRING=${linker_options}"
-    )
-
-    if(TEST_static_link_order)
-        set_property(GLOBAL PROPERTY QT_LINK_ORDER_MATTERS FALSE)
-        set(summary_message "no")
+    # The CMake versions greater than 3.21 take care about the resource object files order in a
+    # linker line, it's expected that all object files are located at the beginning of the linker
+    # line.
+    # No need to run the test.
+    # TODO: This check is added before the actual release of CMake 3.21. So need to check if the
+    # target version meets the expectations.
+    if(CMAKE_VERSION VERSION_LESS 3.21)
+        __qt_internal_check_link_order_matters(${QT_CMAKE_EXPORT_NAMESPACE}::Platform)
+        if(link_order_matters)
+            set(summary_message "no")
+        else()
+            set(summary_message "yes")
+        endif()
     else()
-        set_property(GLOBAL PROPERTY QT_LINK_ORDER_MATTERS TRUE)
         set(summary_message "yes")
     endif()
     qt_configure_add_summary_entry(TYPE "message"