Don't rely on the module.pri for the entrypoint linking to the library

Depending on the presence and behavior of HEADER_MODULE/header_module
in CMake and qmake land, the module.pri might end up with an empty
module line, which means adding the module via QT_PRIVATE += entrypoint
will not link to the static library.

To avoid this problem we write an explicit module entry (QT.foo.bar)
into the same module.pri file as the one generated by qt_module,
where the auto-generated one has header_module enabled, and hence
no link behavior, while the manually written entry has a module
component, and will ensure linkage to the static library.

Change-Id: Ib98484f74410fab45c4d109f3610028200fba0c5
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

mkspecs/features/qt_module.prf

@@ -57,9 +57,9 @@ ucmodule = $$upper($$MODULE)
 isEmpty(MODULE_INCNAME): MODULE_INCNAME = $$TARGET
 
 internal_module: \
-    MODULE_DEPENDS = $$replace(QT, -private$, _private)
+    MODULE_DEPENDS += $$replace(QT, -private$, _private)
 else: \
-    MODULE_DEPENDS = $$replace(QT, -private$, )
+    MODULE_DEPENDS += $$replace(QT, -private$, )
 MODULE_DEPENDS = $$unique(MODULE_DEPENDS)
 contains(MODULE_DEPENDS, $$MODULE): \
     error("$$TARGET depends on itself.")

mkspecs/features/qt_module_pris.prf

@@ -154,8 +154,8 @@ defineReplace(qtExportLibsForModule) {
         $$qtGetExportsForModule($$MODULE_ID) \
         "QT_CONFIG +=$$join(QT.$${MODULE_ID}.QT_CONFIG, " ", " ")" \
         "" \
-        "QT_MODULES += $$MODULE" \
+        "QT_MODULES += $$MODULE"
-        "$$MODULE_PRI_EXTRA_CONTENT"
+    MODULE_PRI_CONT += $$MODULE_PRI_EXTRA_CONTENT
     write_file($$MODULE_PRI, MODULE_PRI_CONT)|error()
     !internal_module:!no_private_module {
         module_build_type += internal_module

src/entrypoint/CMakeLists.txt

@@ -25,16 +25,6 @@ set_target_properties(EntryPoint PROPERTIES
     INTERFACE_COMPILE_DEFINITIONS ""
 )
 
-# And since this module is the one producing the module pri,
-# we need to manually tell it that what we're actually doing
-# is producing a module that has a static library.
-set_target_properties(EntryPoint PROPERTIES
-    INTERFACE_QT_MODULE_INTERNAL_CONFIG "staticlib"
-)
-
-set(module_pri_entrypoint_ldflags "")
-
-
 # ---- While the static library target does the work ----
 qt_internal_add_cmake_library(EntryPointImplementation STATIC
     INCLUDE_DIRECTORIES
@@ -69,7 +59,7 @@ if(WIN32)
         # linker line, so that the static linker will pick up the WinMain symbol
         # from the entry-point library.
         target_link_libraries(EntryPoint INTERFACE mingw32)
-        list(APPEND module_pri_entrypoint_ldflags "-lmingw32")
+        set_property(TARGET EntryPoint APPEND PROPERTY INTERFACE_QT_MODULE_LDFLAGS "-lmingw32")
 
         target_compile_definitions(EntryPoint INTERFACE QT_NEEDS_QMAIN)
         qt_internal_extend_target(EntryPointImplementation DEFINES QT_NEEDS_QMAIN)
@@ -78,14 +68,22 @@ endif()
 
 # ---- Finally, make sure the static library can be consumed by clients -----
 
-set_target_properties(EntryPoint PROPERTIES
-   INTERFACE_QT_MODULE_LDFLAGS "${module_pri_entrypoint_ldflags}"
-)
-
-# Must be added last, so that any library dependencies added above will
-# precede the entrypoint library at link time.
 target_link_libraries(EntryPoint INTERFACE EntryPointImplementation)
 
+qt_internal_get_target_property(entrypoint_implementation_ldflags
+    EntryPointImplementation QT_MODULE_LDFLAGS)
+
+set_target_properties(EntryPoint PROPERTIES
+    INTERFACE_QT_MODULE_PRI_EXTRA_CONTENT "
+QT.entrypoint_implementation.name = QtEntryPointImplementation
+QT.entrypoint_implementation.module = Qt6EntryPoint
+QT.entrypoint_implementation.ldflags = ${entrypoint_implementation_ldflags}
+QT.entrypoint_implementation.libs = $$QT_MODULE_LIB_BASE
+QT.entrypoint_implementation.module_config = staticlib v2 internal_module
+"
+    INTERFACE_QT_MODULE_DEPENDS "entrypoint_implementation"
+)
+
 set(export_name "${INSTALL_CMAKE_NAMESPACE}EntryPointTargets")
 qt_install(TARGETS EntryPointImplementation EXPORT ${export_name})
 qt_generate_prl_file(EntryPointImplementation "${INSTALL_LIBDIR}")

src/entrypoint/entrypoint.pro

@@ -1,34 +1,8 @@
 # Additional Qt project file for QtEntryPoint lib
 !win32:error("$$_FILE_ is intended only for Windows!")
 
-TARGET = QtEntryPoint
+TEMPLATE = subdirs
+CONFIG += ordered
 
-CONFIG += static no_module_headers internal_module
+SUBDIRS += entrypoint_module.pro
-QT = core
+SUBDIRS += entrypoint_implementation.pro
-
-DEFINES += QT_NO_FOREACH
-
-win32 {
-    SOURCES = qtentrypoint_win.cpp
-    CONFIG -= qt
-
-    QMAKE_USE_PRIVATE += shell32
-
-    msvc {
-        QMAKE_CFLAGS_DEBUG -= -Zi
-        QMAKE_CXXFLAGS_DEBUG -= -Zi
-        QMAKE_CFLAGS_DEBUG *= -Z7
-        QMAKE_CXXFLAGS_DEBUG *= -Z7
-    }
-    mingw {
-        DEFINES += QT_NEEDS_QMAIN
-        MODULE_DEFINES += QT_NEEDS_QMAIN
-
-        # This library needs to come before the entry-point library in the
-        # linker line, so that the static linker will pick up the WinMain
-        # symbol from the entry-point library.
-        MODULE_LDFLAGS += -lmingw32
-    }
-}
-
-load(qt_module)

src/entrypoint/entrypoint_implementation.pro

@@ -0,0 +1,61 @@
+
+TEMPLATE = lib
+
+TARGET = QtEntryPoint
+
+CONFIG += static no_module_headers internal_module
+QT = core
+
+DEFINES += QT_NO_FOREACH
+
+win32 {
+    SOURCES = qtentrypoint_win.cpp
+    CONFIG -= qt
+
+    QMAKE_USE_PRIVATE += shell32
+
+    msvc {
+        QMAKE_CFLAGS_DEBUG -= -Zi
+        QMAKE_CXXFLAGS_DEBUG -= -Zi
+        QMAKE_CFLAGS_DEBUG *= -Z7
+        QMAKE_CXXFLAGS_DEBUG *= -Z7
+    }
+    mingw {
+        DEFINES += QT_NEEDS_QMAIN
+        MODULE_DEFINES += QT_NEEDS_QMAIN
+
+        # This library needs to come before the entry-point library in the
+        # linker line, so that the static linker will pick up the WinMain
+        # symbol from the entry-point library.
+        MODULE_LDFLAGS += -lmingw32
+    }
+}
+
+# Minimal qt_helper_lib
+
+load(qt_build_paths)
+load(qt_common)
+
+!build_pass {
+    MODULE_PRI_CONTENT = \
+        "QT.entrypoint_implementation.name = QtEntryPointImplementation" \
+        "QT.entrypoint_implementation.module = Qt6EntryPoint" \
+        "QT.entrypoint_implementation.ldflags = $$MODULE_LDFLAGS" \
+        "QT.entrypoint_implementation.libs = \$\$QT_MODULE_LIB_BASE" \
+        "QT.entrypoint_implementation.DEFINES = $$MODULE_DEFINES" \
+        "QT.entrypoint_implementation.module_config = staticlib v2 internal_module"
+
+    module_path = $$MODULE_QMAKE_OUTDIR/mkspecs/modules
+    force_independent|split_incpath: module_path = "$${module_path}-inst"
+    MODULE_PRI = $$module_path/qt_lib_entrypoint_private.pri
+    write_file($$MODULE_PRI, MODULE_PRI_CONTENT, append)|error()
+}
+
+qtConfig(debug_and_release): CONFIG += debug_and_release
+qtConfig(build_all): CONFIG += build_all
+
+DESTDIR = $$MODULE_BASE_OUTDIR/lib
+
+TARGET = $$qt5LibraryTarget($$TARGET)
+
+load(qt_installs)

src/entrypoint/entrypoint_module.pro

@@ -0,0 +1,10 @@
+
+TARGET = QtEntryPoint
+MODULE = entrypoint
+
+CONFIG += header_module no_module_headers internal_module
+
+MODULE_DEPENDS = entrypoint_implementation
+QT =
+
+load(qt_module)