Generalize the winmain/qtmain entry-point library

The use-case is relevant for other platforms as well.

Now that Qt has a module system we can also replace a lot of the
hand crafted logic for linking with simpler constructs.

Change-Id: Ib6853aaf81bfea79c31f2de741d65b4b56f23ef6
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

cmake/QtFindPackageHelpers.cmake

@@ -195,14 +195,14 @@ endfunction()
 
 # This function records a dependency between ${main_target_name} and ${dep_target_name}
 # at the CMake package level.
-# E.g. Qt6CoreConfig.cmake needs to find_package(Qt6WinMain).
+# E.g. Qt6CoreConfig.cmake needs to find_package(Qt6EntryPoint).
 # main_target_name = Core
-# dep_target_name = WinMain
+# dep_target_name = EntryPoint
 # This is just a convenience function that deals with Qt targets and their associated packages
 # instead of raw package names.
 function(qt_record_extra_qt_package_dependency main_target_name dep_target_name
                                                                 dep_package_version)
-    # WinMain -> Qt6WinMain.
+    # EntryPoint -> Qt6EntryPoint.
     qt_internal_module_info(qtfied_target_name "${dep_target_name}")
     qt_record_extra_package_dependency("${main_target_name}" "${qtfied_target_name_versioned}"
                                                              "${dep_package_version}")

cmake/QtStartupHelpers.cmake

@@ -8,9 +8,9 @@
 function(qt_internal_setup_startup_target)
     set(dependent_target "Core")
 
-    # On windows, find_package(Qt6Core) should call find_package(Qt6WinMain) so that Startup can
-    # link against WinMain.
+    # On windows, find_package(Qt6Core) should call find_package(Qt6EntryPoint) so that Startup can
+    # link against EntryPoint.
     if(WIN32)
-        qt_record_extra_qt_package_dependency("${dependent_target}" WinMain "${PROJECT_VERSION}")
+        qt_record_extra_qt_package_dependency("${dependent_target}" EntryPoint "${PROJECT_VERSION}")
     endif()
 endfunction()

mkspecs/common/g++-win32.conf

@@ -63,7 +63,6 @@ QMAKE_LIBS_OPENGL       = -lglu32 -lopengl32 -lgdi32 -luser32
 QMAKE_LIBS_OPENGL_ES2   = -lgdi32 -luser32
 QMAKE_LIBS_OPENGL_ES2_DEBUG = -lgdi32 -luser32
 QMAKE_LIBS_COMPAT       = -ladvapi32 -lshell32 -lcomdlg32 -luser32 -lgdi32 -lws2_32
-QMAKE_LIBS_QT_ENTRY     = -lmingw32 -lqtmain
 
 QMAKE_IDL               = midl
 QMAKE_LIB               = $${CROSS_COMPILE}ar -rc

mkspecs/common/msvc-desktop.conf

@@ -105,7 +105,6 @@ QMAKE_LIBS_OPENGL       = glu32.lib opengl32.lib gdi32.lib user32.lib
 QMAKE_LIBS_OPENGL_ES2   = gdi32.lib user32.lib
 QMAKE_LIBS_OPENGL_ES2_DEBUG = gdi32.lib user32.lib
 QMAKE_LIBS_COMPAT       = advapi32.lib shell32.lib comdlg32.lib user32.lib gdi32.lib ws2_32.lib
-QMAKE_LIBS_QT_ENTRY     = -lqtmain
 
 QMAKE_IDL               = midl
 QMAKE_LIB               = lib /NOLOGO

mkspecs/features/entrypoint.prf

@@ -0,0 +1,2 @@
+qt:!console:contains(TEMPLATE, ".*app"): \
+    QT_PRIVATE += entrypoint

mkspecs/features/win32/default_pre.prf

@@ -1,2 +1,2 @@
-CONFIG = windows $$CONFIG
+CONFIG = windows $$CONFIG entrypoint
 load(default_pre)

mkspecs/features/win32/idcidl.prf

@@ -3,8 +3,7 @@ build_pass:console {
     warning("Remove 'console' from your CONFIG.")
 }
 
-# Do not link qtmain.lib
-QMAKE_LIBS_QT_ENTRY =
+CONFIG -= entrypoint
 
 ACTIVEQT_VERSION = $$VERSION
 isEmpty(ACTIVEQT_VERSION):ACTIVEQT_VERSION = 1.0

mkspecs/features/win32/windows.prf

@@ -2,15 +2,4 @@ CONFIG -= console
 QMAKE_LFLAGS += $$QMAKE_LFLAGS_WINDOWS
 contains(TEMPLATE, ".*app") {
     QMAKE_LFLAGS += $$QMAKE_LFLAGS_EXE
-    mingw:DEFINES += QT_NEEDS_QMAIN
-
-    qt:for(entryLib, $$list($$unique(QMAKE_LIBS_QT_ENTRY))) {
-        isEqual(entryLib, -lqtmain) {
-            lib = $$QT.core.libs/$${QMAKE_PREFIX_STATICLIB}qtmain$$QT_LIBINFIX$$qtPlatformTargetSuffix().$$QMAKE_EXTENSION_STATICLIB
-            PRE_TARGETDEPS += $$lib
-            QMAKE_LIBS += $$lib
-        } else {
-            QMAKE_LIBS += $${entryLib}
-        }
-    }
 }

src/CMakeLists.txt

@@ -70,6 +70,6 @@ if(QT_FEATURE_gui AND QT_FEATURE_widgets)
 endif()
 add_subdirectory(plugins)
 
-add_subdirectory(winmain)
+add_subdirectory(entrypoint)
 
 add_subdirectory(android)

src/corelib/Qt6CoreMacros.cmake

@@ -1370,7 +1370,7 @@ function(_qt_internal_setup_startup_target)
         set_target_properties("${target}" PROPERTIES "${initialized_prop}" TRUE)
     endif()
 
-    # On Windows this enables automatic linkage to WinMain.
+    # On Windows this enables automatic linkage to QtEntryPoint.
     # On iOS this enables automatic passing of a linker flag that will change the default
     # entry point of the linked executable.
     set(isExe "$<STREQUAL:$<TARGET_PROPERTY:TYPE>,EXECUTABLE>")
@@ -1378,7 +1378,7 @@ function(_qt_internal_setup_startup_target)
     if(WIN32)
         set(isWin32 "$<BOOL:$<TARGET_PROPERTY:WIN32_EXECUTABLE>>")
         set(isPolicyNEW "$<TARGET_POLICY:CMP0020>")
-        set(finalGenex "$<$<AND:${isExe},${isWin32},${isNotExcluded},${isPolicyNEW}>:Qt::WinMain>")
+        set(finalGenex "$<$<AND:${isExe},${isWin32},${isNotExcluded},${isPolicyNEW}>:Qt::EntryPoint>")
 
         # Use set_target_properties instead of target_link_libraries because the latter has some
         # weird additional behavior of checking which project the target belongs to, and might

src/corelib/doc/src/qtcore-index.qdoc

@@ -116,7 +116,7 @@
     See \l{Qt Licensing} for further details.
 
     Executables on Windows potentially link
-    against \l{The qtmain Library}. This library is available
+    against \l{The QtEntryPoint Library}. This library is available
     under commercial licenses and also under the
     \l{BSD 3-clause "New" or "Revised" License}.
 

src/entrypoint/CMakeLists.txt

@@ -4,7 +4,7 @@ if (NOT WIN32)
     return()
 endif()
 
-qt_internal_add_module(WinMain
+qt_internal_add_module(EntryPoint
   STATIC
   NO_SYNC_QT
   NO_MODULE_HEADERS
@@ -22,14 +22,12 @@ if (MSVC)
         IN_CURRENT_SCOPE)
 endif()
 
-set_property(TARGET WinMain PROPERTY OUTPUT_NAME qtmain)
-
-qt_internal_extend_target(WinMain CONDITION
-    SOURCES qtmain_win.cpp
+qt_internal_extend_target(EntryPoint CONDITION WIN32
+    SOURCES qtentrypoint_win.cpp
     LIBRARIES shell32
 )
 
-qt_internal_extend_target(WinMain CONDITION MINGW
+qt_internal_extend_target(EntryPoint CONDITION MINGW
     DEFINES QT_NEEDS_QMAIN
 )
 # special case end

src/entrypoint/entrypoint.pro

@@ -0,0 +1,30 @@
+# Additional Qt project file for QtEntryPoint lib
+!win32:error("$$_FILE_ is intended only for Windows!")
+
+TARGET = QtEntryPoint
+
+CONFIG += static no_module_headers
+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
+        LIBS += -lmingw32
+    }
+}
+
+load(qt_module)

src/entrypoint/qtentrypoint_win.cpp

@@ -52,8 +52,8 @@
 #include <shellapi.h>
 
 /*
-  This file contains the code in the qtmain library for Windows.
-  qtmain contains the Windows startup code and is required for
+  This file contains the code in the QtEntryPoint library for Windows.
+  QtEntryPoint contains the Windows startup code and is required for
   linking to the Qt DLL.
 
   When a Windows application starts, the WinMain function is

src/src.pro

@@ -64,9 +64,9 @@ src_tools_qvkgen.target = sub-qvkgen
 force_bootstrap: src_tools_qvkgen.depends = src_tools_bootstrap
 else: src_tools_qvkgen.depends = src_corelib
 
-src_winmain.subdir = $$PWD/winmain
-src_winmain.target = sub-winmain
-src_winmain.depends = sub-corelib  # just for the module .pri file
+src_entrypoint.subdir = $$PWD/entrypoint
+src_entrypoint.target = sub-entrypoint
+src_entrypoint.depends = sub-corelib  # just for the module .pri file
 
 src_corelib.subdir = $$PWD/corelib
 src_corelib.target = sub-corelib
@@ -157,7 +157,9 @@ qtConfig(regularexpression):!qtConfig(system-pcre2):pcre2 {
 }
 TOOLS = src_tools_moc src_tools_rcc src_tools_tracegen src_tools_qlalr
 SUBDIRS += src_corelib src_tools_qlalr
-win32:SUBDIRS += src_winmain
+
+win32:SUBDIRS += src_entrypoint
+
 qtConfig(network) {
     SUBDIRS += src_network
     src_plugins.depends += src_network

src/winmain/winmain.pro

@@ -1,31 +0,0 @@
-# Additional Qt project file for qtmain lib on Windows
-!win32:error("$$_FILE_ is intended only for Windows!")
-
-TEMPLATE = lib
-TARGET = qtmain
-DESTDIR = $$QT.core.libs
-
-CONFIG += static
-QT = core
-
-DEFINES += QT_NO_FOREACH
-
-qtConfig(debug_and_release): CONFIG += build_all
-
-msvc: QMAKE_CFLAGS_DEBUG -= -Zi
-msvc: QMAKE_CXXFLAGS_DEBUG -= -Zi
-msvc: QMAKE_CFLAGS_DEBUG *= -Z7
-msvc: QMAKE_CXXFLAGS_DEBUG *= -Z7
-mingw: DEFINES += QT_NEEDS_QMAIN
-
-CONFIG -= qt
-SOURCES = qtmain_win.cpp
-QMAKE_USE_PRIVATE += shell32
-
-load(qt_installs)
-
-TARGET = $$qtLibraryTarget($$TARGET$$QT_LIBINFIX) #do this towards the end
-
-load(qt_targets)
-load(qt_build_paths)
-load(qt_common)