Skip unnecessary commands when cross-building tools

Introduce a new macro qt_internal_return_unless_building_tools which
simply calls return() if tools are not built.  This macro is supposed to
be called after qt_internal_add_tool().

Using this macro avoids having to special-case code for when
qt_internal_add_tool() creates imported targets in cross-builds.

Adjust pro2cmake accordingly.

Task-number: QTBUG-85084
Change-Id: I9e1c455c29535dd8c318efa890ebd739c42effc1
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

cmake/QtToolHelpers.cmake

@@ -441,6 +441,14 @@ function(qt_check_if_tools_will_be_built)
     set(QT_WILL_BUILD_TOOLS ${will_build_tools} CACHE INTERNAL "Are tools going to be built" FORCE)
 endfunction()
 
+# Use this macro to exit a file or function scope unless we're building tools. This is supposed to
+# be called after qt_internal_add_tools() to avoid special-casing operations on imported targets.
+macro(qt_internal_return_unless_building_tools)
+    if(NOT QT_WILL_BUILD_TOOLS)
+        return()
+    endif()
+endmacro()
+
 # Equivalent of qmake's qtNomakeTools(directory1 directory2).
 # If QT_BUILD_TOOLS_BY_DEFAULT is true, then targets within the given directories will be excluded
 # from the default 'all' target, as well as from install phase. The private variable is checked by

qmake/CMakeLists.txt

@@ -97,6 +97,7 @@ qt_internal_add_tool(${target_name}
         Qt::CorePrivate
         QtLibraryInfo
 )
+qt_internal_return_unless_building_tools()
 
 # Add QMAKE_VERSION_STR only if qmake is part of the build.
 target_compile_definitions(QtLibraryInfo PUBLIC

src/tools/androiddeployqt/CMakeLists.txt

@@ -19,6 +19,7 @@ qt_internal_add_tool(${target_name}
     INCLUDE_DIRECTORIES
         ../shared
 )
+qt_internal_return_unless_building_tools()
 set_target_properties(${target_name} PROPERTIES
     WIN32_EXECUTABLE FALSE
 )

src/tools/androidtestrunner/CMakeLists.txt

@@ -17,6 +17,7 @@ qt_internal_add_tool(${target_name}
     PUBLIC_LIBRARIES
         Qt::Gui
 )
+qt_internal_return_unless_building_tools()
 set_target_properties(${target_name} PROPERTIES
     WIN32_EXECUTABLE FALSE
 )

src/tools/cmake_automoc_parser/CMakeLists.txt

@@ -18,3 +18,4 @@ qt_internal_add_tool(${target_name}
     INCLUDE_DIRECTORIES
         ${CMAKE_CURRENT_SOURCE_DIR}
 )
+qt_internal_return_unless_building_tools()

src/tools/moc/CMakeLists.txt

@@ -34,6 +34,7 @@ qt_internal_add_tool(${target_name}
         ../../3rdparty/tinycbor/src
         ../shared
 )
+qt_internal_return_unless_building_tools()
 
 #### Keys ignored in scope 1:.:.:moc.pro:<TRUE>:
 # QMAKE_TARGET_DESCRIPTION = "Qt Meta Object Compiler"

src/tools/qdbuscpp2xml/CMakeLists.txt

@@ -35,6 +35,7 @@ qt_internal_add_tool(${target_name}
     # _LOADED = "qt_tool"
     # _OPTION = "host_build"
 )
+qt_internal_return_unless_building_tools()
 
 #### Keys ignored in scope 1:.:.:qdbuscpp2xml.pro:<TRUE>:
 # QMAKE_TARGET_DESCRIPTION = "Qt D-Bus C++ to XML Compiler"

src/tools/qdbusxml2cpp/CMakeLists.txt

@@ -22,6 +22,7 @@ qt_internal_add_tool(${target_name}
     # _LOADED = "qt_tool"
     # _OPTION = "host_build"
 )
+qt_internal_return_unless_building_tools()
 
 #### Keys ignored in scope 1:.:.:qdbusxml2cpp.pro:<TRUE>:
 # QMAKE_TARGET_DESCRIPTION = "Qt D-Bus XML to C++ Compiler"

src/tools/qlalr/CMakeLists.txt

@@ -23,6 +23,7 @@ qt_internal_add_tool(${target_name}
     PUBLIC_LIBRARIES
         Qt::Core # special case
 )
+qt_internal_return_unless_building_tools()
 
 #### Keys ignored in scope 1:.:.:qlalr.pro:<TRUE>:
 # OTHER_FILES = "lalr.g"

src/tools/qtpaths/CMakeLists.txt

@@ -15,6 +15,7 @@ qt_internal_add_tool(${target_name}
         QT_NO_FOREACH
         QTPATHS_VERSION_STR="2.0"
 )
+qt_internal_return_unless_building_tools()
 
 ## Scopes:
 #####################################################################

src/tools/qvkgen/CMakeLists.txt

@@ -14,6 +14,7 @@ qt_internal_add_tool(${target_name}
     PUBLIC_LIBRARIES
         Qt::Core # special case
 )
+qt_internal_return_unless_building_tools()
 
 #### Keys ignored in scope 1:.:.:qvkgen.pro:<TRUE>:
 # QMAKE_TARGET_DESCRIPTION = "Qt Vulkan Header Generator"

src/tools/rcc/CMakeLists.txt

@@ -19,6 +19,7 @@ qt_internal_add_tool(${target_name}
     INCLUDE_DIRECTORIES
         ${CMAKE_CURRENT_SOURCE_DIR}
 )
+qt_internal_return_unless_building_tools()
 
 #### Keys ignored in scope 1:.:.:rcc.pro:<TRUE>:
 # QMAKE_TARGET_DESCRIPTION = "Qt Resource Compiler"

src/tools/tracegen/CMakeLists.txt

@@ -18,6 +18,7 @@ qt_internal_add_tool(${target_name}
         qtheaders.cpp qtheaders.h
         tracegen.cpp
 )
+qt_internal_return_unless_building_tools()
 
 #### Keys ignored in scope 1:.:.:tracegen.pro:<TRUE>:
 # _OPTION = "host_build"

src/tools/uic/CMakeLists.txt

@@ -40,6 +40,7 @@ qt_internal_add_tool(${target_name}
     #PUBLIC_LIBRARIES # special case remove
         #Qt::Gui # special case remove
 )
+qt_internal_return_unless_building_tools()
 
 #### Keys ignored in scope 1:.:.:uic.pro:<TRUE>:
 # QMAKE_TARGET_DESCRIPTION = "Qt User Interface Compiler"

util/cmake/pro2cmake.py

@@ -3246,6 +3246,9 @@ def write_main_part(
     # Footer:
     cm_fh.write(f"{spaces(indent)})\n")
 
+    if typename == "Tool":
+        cm_fh.write(f"{spaces(indent)}qt_internal_return_unless_building_tools()\n")
+
     write_resources(cm_fh, name, scope, indent, target_ref=target_ref)
 
     write_statecharts(cm_fh, name, scope, indent)