Move iOS entrypoint logic to entrypoint library

Change-Id: Ie0fc8368953a59d06a31847ed417bc3c35f29b90
Reviewed-by: Alexandru Croitor <[email protected]>

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(Qt6EntryPoint) so that Startup can
-    # link against EntryPoint.
-    if(WIN32)
+    # On platforms that have a Qt entry-point, find_package(Qt6Core) should call
+    # find_package(Qt6EntryPoint) so that we can link against EntryPoint.
+    if(WIN32 OR CMAKE_SYSTEM_NAME STREQUAL "iOS")
         qt_record_extra_qt_package_dependency("${dependent_target}" EntryPoint "${PROJECT_VERSION}")
     endif()
 endfunction()

mkspecs/features/entrypoint.prf

@@ -1,2 +1,10 @@
-qt:!console:contains(TEMPLATE, ".*app"): \
-    QT_PRIVATE += entrypoint_private
+!qt: return()
+
+win32 {
+    !console:contains(TEMPLATE, ".*app"): \
+        QT_PRIVATE += entrypoint_private
+} else:uikit {
+    qt_depends = $$resolve_depends(QT, "QT.")
+    !watchos:equals(TEMPLATE, app):contains(qt_depends, gui(-private)?): \
+        QT_PRIVATE += entrypoint_private
+}

mkspecs/features/uikit/default_pre.prf

@@ -16,6 +16,8 @@ $$sim_and_dev {
     DEFINES += QT_COMPILER_SUPPORTS_SSE2
 }
 
+CONFIG += entrypoint
+
 unset(sim_and_dev)
 
 load(default_pre)

src/corelib/Qt6CoreMacros.cmake

@@ -1415,8 +1415,7 @@ function(_qt_internal_setup_startup_target)
         # error out when called multiple times from different scopes.
         set_target_properties("${target}" PROPERTIES INTERFACE_LINK_LIBRARIES "${finalGenex}")
     elseif(CMAKE_SYSTEM_NAME STREQUAL "iOS")
-        set(flag "-Wl,-e,_qt_main_wrapper")
-        set(finalGenex "$<$<AND:${isExe},${isNotExcluded}>:${flag}>")
+        set(finalGenex "$<$<AND:${isExe},${isNotExcluded}>Qt::EntryPoint>")
 
         set_target_properties("${target}" PROPERTIES INTERFACE_LINK_OPTIONS "${finalGenex}")
     endif()

src/entrypoint/CMakeLists.txt

@@ -1,6 +1,6 @@
 # special case begin
 # special case skip regeneration
-if (NOT WIN32)
+if (NOT WIN32 AND NOT CMAKE_SYSTEM_NAME STREQUAL "iOS")
     return()
 endif()
 
@@ -25,18 +25,25 @@ set_target_properties(EntryPoint PROPERTIES
     INTERFACE_COMPILE_DEFINITIONS ""
 )
 
-# ---- While the static library target does the work ----
-qt_internal_add_cmake_library(EntryPointImplementation STATIC
-    INCLUDE_DIRECTORIES
-       $<TARGET_PROPERTY:Qt::Core,INTERFACE_INCLUDE_DIRECTORIES>
-)
+if(WIN32)
+    # Not all platforms require the static library
+    set(using_entrypoint_library "yes")
+endif()
 
-set_target_properties(EntryPointImplementation PROPERTIES
-    OUTPUT_NAME "${INSTALL_CMAKE_NAMESPACE}EntryPoint${QT_LIBINFIX}"
-    ARCHIVE_OUTPUT_DIRECTORY "${QT_BUILD_DIR}/${INSTALL_LIBDIR}"
-)
+if(using_entrypoint_library)
+    # ---- While the static library target does the work ----
+    qt_internal_add_cmake_library(EntryPointImplementation STATIC
+        INCLUDE_DIRECTORIES
+           $<TARGET_PROPERTY:Qt::Core,INTERFACE_INCLUDE_DIRECTORIES>
+    )
+
+    set_target_properties(EntryPointImplementation PROPERTIES
+        OUTPUT_NAME "${INSTALL_CMAKE_NAMESPACE}EntryPoint${QT_LIBINFIX}"
+        ARCHIVE_OUTPUT_DIRECTORY "${QT_BUILD_DIR}/${INSTALL_LIBDIR}"
+    )
 
-qt_internal_add_target_aliases(EntryPointImplementation)
+    qt_internal_add_target_aliases(EntryPointImplementation)
+endif()
 
 # ---- Now we're ready to set up the platform specifics ----
 
@@ -66,26 +73,33 @@ if(WIN32)
     endif()
 endif()
 
-# ---- Finally, make sure the static library can be consumed by clients -----
-
-target_link_libraries(EntryPoint INTERFACE EntryPointImplementation)
+if(CMAKE_SYSTEM_NAME STREQUAL "iOS")
+    set_target_properties(EntryPoint PROPERTIES INTERFACE_LINK_OPTIONS "-Wl,-e,_qt_main_wrapper")
+    set_property(TARGET EntryPoint APPEND PROPERTY INTERFACE_QT_MODULE_LDFLAGS "-Wl,-e,_qt_main_wrapper")
+endif()
 
-qt_internal_get_target_property(entrypoint_implementation_ldflags
-    EntryPointImplementation QT_MODULE_LDFLAGS)
+# ---- Finally, make sure the static library can be consumed by clients -----
 
-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 = $$QT_MODULE_LIB_BASE
-QT.entrypoint_implementation.module_config = staticlib v2 internal_module
-"
-    INTERFACE_QT_MODULE_DEPENDS "entrypoint_implementation"
-)
+if(using_entrypoint_library)
+    target_link_libraries(EntryPoint INTERFACE EntryPointImplementation)
+
+    qt_internal_get_target_property(entrypoint_implementation_ldflags
+        EntryPointImplementation QT_MODULE_LDFLAGS)
+
+    set_target_properties(EntryPoint PROPERTIES
+        INTERFACE_QT_MODULE_PRI_EXTRA_CONTENT "
+    QT.entrypoint_implementation.name = QtEntryPointImplementation
+    QT.entrypoint_implementation.module = Qt6EntryPoint
+    QT.entrypoint_implementation.ldflags = ${entrypoint_implementation_ldflags}
+    QT.entrypoint_implementation.libs = $$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}")
+    set(export_name "${INSTALL_CMAKE_NAMESPACE}EntryPointTargets")
+    qt_install(TARGETS EntryPointImplementation EXPORT ${export_name})
+    qt_generate_prl_file(EntryPointImplementation "${INSTALL_LIBDIR}")
+endif()
 
 # special case end

src/entrypoint/entrypoint.pro

@@ -1,8 +1,9 @@
-# Additional Qt project file for QtEntryPoint lib
-!win32:error("$$_FILE_ is intended only for Windows!")
 
 TEMPLATE = subdirs
 CONFIG += ordered
 
 SUBDIRS += entrypoint_module.pro
-SUBDIRS += entrypoint_implementation.pro
+
+win32 {
+    SUBDIRS += entrypoint_implementation.pro
+}

src/entrypoint/entrypoint_module.pro

@@ -4,22 +4,36 @@ MODULE = entrypoint
 
 CONFIG += header_module no_module_headers internal_module
 
-MODULE_DEPENDS = entrypoint_implementation
 QT =
 
-mingw {
-    MODULE_DEFINES += QT_NEEDS_QMAIN
+win32 {
+    MODULE_DEPENDS = entrypoint_implementation
 
-    # 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
+    mingw {
+        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
+    }
+}
+
+uikit {
+    # The LC_MAIN load command available in iOS 6.0 and above allows dyld to
+    # directly call the entrypoint instead of going through _start in crt.o.
+    # Passing -e to the linker changes the entrypoint from _main to our custom
+    # wrapper that calls UIApplicationMain and dispatches back to main() once
+    # the application has started up and is ready to initialize QApplication.
+    MODULE_LDFLAGS += -Wl,-e,_qt_main_wrapper
 }
 
-MODULE_PRI_EXTRA_CONTENT = \
-    "QT.entrypoint_implementation.name = QtEntryPointImplementation" \
-    "QT.entrypoint_implementation.module = Qt6EntryPoint" \
-    "QT.entrypoint_implementation.libs = \$\$QT_MODULE_LIB_BASE" \
-    "QT.entrypoint_implementation.module_config = staticlib v2 internal_module"
+contains(MODULE_DEPENDS, entrypoint_implementation) {
+    MODULE_PRI_EXTRA_CONTENT = \
+        "QT.entrypoint_implementation.name = QtEntryPointImplementation" \
+        "QT.entrypoint_implementation.module = Qt6EntryPoint" \
+        "QT.entrypoint_implementation.libs = \$\$QT_MODULE_LIB_BASE" \
+        "QT.entrypoint_implementation.module_config = staticlib v2 internal_module"
+}
 
 load(qt_module)

src/src.pro

@@ -158,7 +158,7 @@ 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_entrypoint
+uikit|win32:SUBDIRS += src_entrypoint
 
 qtConfig(network) {
     SUBDIRS += src_network