pro2cmake: Handle QT += core-private correctly for modules

If a module project (Quick) contains QT += core-private, the
qmake semantics translated to CMake would mean the following:

target_link_libraries(Quick PUBLIC Core)
target_link_libraries(Quick PRIVATE CorePrivate)
target_link_libraries(QuickPrivate INTERFACE CorePrivate)

Whereas a QT_PRIVATE += core-private only means
target_link_libraries(Quick PRIVATE CorePrivate)

without adding any public dependencies to QuickPrivate.

To achieve that, we need a few modifications to both pro2cmake and
QtBuild.cmake

- pro2cmake doesn't automagically add public and private dependencies
  to targets when encountering a private module assigned to QT.
  Instead it generates the logic described above by passing correct
  LIBRARIES, PUBLIC_LIBRARIES, and PRIVATE_MODULE_INTERFACE values.

- pro2cmake doesn't do any dependency magic for non-module targets
  anymore, like executables, plugins, internal_modules. This means
  that QT assignments are now regular public dependencies.

- qt_add_module and qt_extend_target now accept a new
  PRIVATE_MODULE_INTERFACE option.

- qt_extend_target does not automagically make private modules be
   public dependencies on other private modules.

- qt_extend_target correctly assigns PRIVATE_MODULE_INTERFACE values
  to Private module only. For other target types, it's a no-op.

The change requires regeneration of all projects.

When we fix pro2cmake and QtBuild.cmake to properly handle
internal_modules (create only Private modules without creating
a non-Private counter part), we will need another project regeneration
to correctly assign dependencies.

Change-Id: I4c21f26b3ef3b2a4ed208b58bccb65a5b7312f81
Task-number: QTBUG-81780
Reviewed-by: Leander Beernaert <leander.beernaert@qt.io>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

cmake/QtBuild.cmake

@@ -946,7 +946,7 @@ endfunction()
 set(__default_private_args "SOURCES;LIBRARIES;INCLUDE_DIRECTORIES;DEFINES;DBUS_ADAPTOR_BASENAME;DBUS_ADAPTOR_FLAGS;DBUS_ADAPTOR_SOURCES;DBUS_INTERFACE_BASENAME;DBUS_INTERFACE_FLAGS;DBUS_INTERFACE_SOURCES;FEATURE_DEPENDENCIES;COMPILE_OPTIONS;LINK_OPTIONS;MOC_OPTIONS;DISABLE_AUTOGEN_TOOLS;ENABLE_AUTOGEN_TOOLS;PLUGIN_TYPES")
 
 set(__default_public_args "PUBLIC_LIBRARIES;PUBLIC_INCLUDE_DIRECTORIES;PUBLIC_DEFINES;PUBLIC_COMPILE_OPTIONS;PUBLIC_LINK_OPTIONS")
-
+set(__default_private_module_args "PRIVATE_MODULE_INTERFACE")
 
 option(QT_CMAKE_DEBUG_EXTEND_TARGET "Debug extend_target calls in Qt's build system" OFF)
 
@@ -1085,7 +1085,7 @@ function(qt_extend_target target)
         message(FATAL_ERROR "Trying to extend non-existing target \"${target}\".")
     endif()
     qt_parse_all_arguments(arg "qt_extend_target" "HEADER_MODULE" "PRECOMPILED_HEADER"
-        "CONDITION;${__default_public_args};${__default_private_args};COMPILE_FLAGS;NO_PCH_SOURCES" ${ARGN})
+        "CONDITION;${__default_public_args};${__default_private_args};${__default_private_module_args};COMPILE_FLAGS;NO_PCH_SOURCES" ${ARGN})
     if ("x${arg_CONDITION}" STREQUAL x)
         set(arg_CONDITION ON)
     endif()
@@ -1193,7 +1193,8 @@ function(qt_extend_target target)
 
         set(target_private "${target}Private")
         if(TARGET "${target_private}")
-          target_link_libraries("${target_private}" INTERFACE "${target}" "${qt_libs_private}")
+          target_link_libraries("${target_private}"
+                                INTERFACE "${target}" ${arg_PRIVATE_MODULE_INTERFACE})
         endif()
         qt_register_target_dependencies("${target}"
                                         "${arg_PUBLIC_LIBRARIES}"
@@ -1533,7 +1534,7 @@ function(qt_add_module target)
     qt_parse_all_arguments(arg "qt_add_module"
         "NO_MODULE_HEADERS;STATIC;DISABLE_TOOLS_EXPORT;EXCEPTIONS;INTERNAL_MODULE;NO_SYNC_QT;NO_PRIVATE_MODULE;HEADER_MODULE;GENERATE_METATYPES"
         "CONFIG_MODULE_NAME;PRECOMPILED_HEADER"
-        "${__default_private_args};${__default_public_args};QMAKE_MODULE_CONFIG;EXTRA_CMAKE_FILES;EXTRA_CMAKE_INCLUDES;NO_PCH_SOURCES" ${ARGN})
+        "${__default_private_args};${__default_public_args};${__default_private_module_args};QMAKE_MODULE_CONFIG;EXTRA_CMAKE_FILES;EXTRA_CMAKE_INCLUDES;NO_PCH_SOURCES" ${ARGN})
 
     if(NOT DEFINED arg_CONFIG_MODULE_NAME)
         set(arg_CONFIG_MODULE_NAME "${module_lower}")
@@ -1751,6 +1752,7 @@ function(qt_add_module target)
             "${deprecation_define}"
         PUBLIC_LIBRARIES ${arg_PUBLIC_LIBRARIES}
         LIBRARIES ${arg_LIBRARIES} Qt::PlatformModuleInternal
+        PRIVATE_MODULE_INTERFACE ${arg_PRIVATE_MODULE_INTERFACE}
         FEATURE_DEPENDENCIES ${arg_FEATURE_DEPENDENCIES}
         DBUS_ADAPTOR_SOURCES ${arg_DBUS_ADAPTOR_SOURCES}
         DBUS_ADAPTOR_FLAGS ${arg_DBUS_ADAPTOR_FLAGS}

util/cmake/pro2cmake.py

@@ -904,6 +904,8 @@ class Scope(object):
         self._visited_keys = set()  # type: Set[str]
         self._total_condition = None  # type: Optional[str]
         self._parent_include_line_no = parent_include_line_no
+        self._is_public_module = False
+        self._has_private_module = False
 
     def __repr__(self):
         return (
@@ -935,6 +937,14 @@ class Scope(object):
     def currentdir(self) -> str:
         return self._currentdir
 
+    @property
+    def is_public_module(self) -> bool:
+        return self._is_public_module
+
+    @property
+    def has_private_module(self) -> bool:
+        return self._has_private_module
+
     def can_merge_condition(self):
         if self._condition == "else":
             return False
@@ -1826,16 +1836,9 @@ def extract_cmake_libraries(
         private_dependencies += [map_qt_library(q) for q in scope.expand(key)]
 
     for key in ["QT"]:
-        # Qt public libs: These may include FooPrivate in which case we get
-        # a private dependency on FooPrivate as well as a public dependency on Foo
         for lib in scope.expand(key):
             mapped_lib = map_qt_library(lib)
-
+            public_dependencies.append(mapped_lib)
-            if mapped_lib.endswith("Private"):
-                private_dependencies.append(mapped_lib)
-                public_dependencies.append(mapped_lib[:-7])
-            else:
-                public_dependencies.append(mapped_lib)
 
     return (
         _map_libraries_to_cmake(public_dependencies, known_libraries, is_example=is_example),
@@ -1972,8 +1975,41 @@ def write_library_section(
         scope, known_libraries=known_libraries
     )
 
-    write_list(cm_fh, private_dependencies, "LIBRARIES", indent + 1)
+    is_public_module = scope.is_public_module
-    write_list(cm_fh, public_dependencies, "PUBLIC_LIBRARIES", indent + 1)
+    current_scope = scope
+    while not is_public_module and current_scope.parent:
+        current_scope = current_scope.parent
+        is_public_module = current_scope.is_public_module
+
+    # When handling module dependencies, handle QT += foo-private magic.
+    # This implies:
+    #  target_link_libraries(Module PUBLIC Qt::Foo)
+    #  target_link_libraries(Module PRIVATE Qt::FooPrivate)
+    #  target_link_libraries(ModulePrivate INTERFACE Qt::FooPrivate)
+    if is_public_module:
+        private_module_dep_pattern = re.compile(r"^(Qt::(.+))Private$")
+
+        public_module_public_deps = []
+        public_module_private_deps = private_dependencies
+        private_module_interface_deps = []
+
+        for dep in public_dependencies:
+            match = re.match(private_module_dep_pattern, dep)
+            if match:
+                if match[1] not in public_module_public_deps:
+                    public_module_public_deps.append(match[1])
+                private_module_interface_deps.append(dep)
+                if dep not in public_module_private_deps:
+                    public_module_private_deps.append(dep)
+            else:
+                if dep not in public_module_public_deps:
+                    public_module_public_deps.append(dep)
+        write_list(cm_fh, public_module_private_deps, "LIBRARIES", indent + 1)
+        write_list(cm_fh, public_module_public_deps, "PUBLIC_LIBRARIES", indent + 1)
+        write_list(cm_fh, private_module_interface_deps, "PRIVATE_MODULE_INTERFACE", indent + 1)
+    else:
+        write_list(cm_fh, private_dependencies, "LIBRARIES", indent + 1)
+        write_list(cm_fh, public_dependencies, "PUBLIC_LIBRARIES", indent + 1)
 
 
 def write_autogen_section(cm_fh: IO[str], scope: Scope, *, indent: int = 0):
@@ -2827,9 +2863,12 @@ def write_module(cm_fh: IO[str], scope: Scope, *, indent: int = 0) -> str:
     # or when option(host_build) is used, as described in qt_module.prf.
     is_static = "static" in scope.get("CONFIG") or "host_build" in scope.get("_OPTION")
 
+    is_public_module = True
+
     if is_static:
         extra.append("STATIC")
     if "internal_module" in scope.get("CONFIG"):
+        is_public_module = False
         extra.append("INTERNAL_MODULE")
     if "no_module_headers" in scope.get("CONFIG"):
         extra.append("NO_MODULE_HEADERS")
@@ -2837,6 +2876,8 @@ def write_module(cm_fh: IO[str], scope: Scope, *, indent: int = 0) -> str:
         extra.append("NO_SYNC_QT")
     if "no_private_module" in scope.get("CONFIG"):
         extra.append("NO_PRIVATE_MODULE")
+    else:
+        scope._has_private_module = True
     if "header_module" in scope.get("CONFIG"):
         extra.append("HEADER_MODULE")
     if "metatypes" in scope.get("CONFIG") or "qmltypes" in scope.get("CONFIG"):
@@ -2850,6 +2891,8 @@ def write_module(cm_fh: IO[str], scope: Scope, *, indent: int = 0) -> str:
     if module_plugin_types:
         extra.append(f"PLUGIN_TYPES {' '.join(module_plugin_types)}")
 
+    scope._is_public_module = is_public_module
+
     target_name = module_name[2:]
     write_main_part(
         cm_fh,