Add some utilities for UNITY_BUILD

- The following commands accepts NO_UNITY_BUILD, and
  NO_UNITY_BUILD_SOURCES arguments to opt out of the unity build, and
  to exclude some source files from unity build, respectively.
  - qt_internal_add_executable
  - qt_internal_add_module
  - qt_internal_add_plugin
  - qt_internal_add_tool
  - qt_internal_extend_target
  - qt_internal_add_common_qt_library_helper
  - qt_internal_add_cmake_library
  - qt_internal_add_simd_part
- Unity build is disabled by default in these:
  - qt_internal_add_test
  - qt_internal_add_test_helper
  - qt_internal_add_benchmark
  - qt_internal_add_3rdparty_library
- qt_update_ignore_pch_source also excludes the files from unity_build

Pick-to: 6.5
Task-number: QTBUG-109394
Change-Id: I5d0e7df633738310a015142a6c73fbb78b6c3467
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

12 files changed, 96 insertions, 6 deletions

diff --git a/cmake/Qt3rdPartyLibraryHelpers.cmake b/cmake/Qt3rdPartyLibraryHelpers.cmake
index 03915938e2..1eef71fe0f 100644
--- a/cmake/Qt3rdPartyLibraryHelpers.cmake
+++ b/cmake/Qt3rdPartyLibraryHelpers.cmake
@@ -4,6 +4,7 @@ macro(qt_internal_get_add_library_option_args option_args)
         STATIC
         MODULE
         INTERFACE
+        NO_UNITY_BUILD
         )
 endmacro()
 
@@ -49,7 +50,18 @@ function(qt_internal_add_common_qt_library_helper target)
         set(arg_MODULE STATIC)
     endif()
 
+    if(arg_NO_UNITY_BUILD)
+        set(arg_NO_UNITY_BUILD NO_UNITY_BUILD)
+    else()
+        set(arg_NO_UNITY_BUILD "")
+    endif()
+
     _qt_internal_add_library(${target} ${arg_STATIC} ${arg_SHARED} ${arg_MODULE} ${arg_INTERFACE})
+
+    if(arg_NO_UNITY_BUILD)
+        set_property(TARGET "${target}" PROPERTY UNITY_BUILD OFF)
+    endif()
+
     qt_internal_mark_as_internal_library(${target})
 endfunction()
 
@@ -98,6 +110,12 @@ function(qt_internal_add_cmake_library target)
         )
     endif()
 
+    if(arg_NO_UNITY_BUILD)
+        set(arg_NO_UNITY_BUILD NO_UNITY_BUILD)
+    else()
+        set(arg_NO_UNITY_BUILD "")
+    endif()
+
     qt_internal_extend_target("${target}"
         SOURCES ${arg_SOURCES}
         INCLUDE_DIRECTORIES
@@ -119,6 +137,8 @@ function(qt_internal_add_cmake_library target)
         MOC_OPTIONS ${arg_MOC_OPTIONS}
         ENABLE_AUTOGEN_TOOLS ${arg_ENABLE_AUTOGEN_TOOLS}
         DISABLE_AUTOGEN_TOOLS ${arg_DISABLE_AUTOGEN_TOOLS}
+        NO_UNITY_BUILD_SOURCES ${arg_NO_UNITY_BUILD_SOURCES}
+        ${arg_NO_UNITY_BUILD}
     )
 endfunction()
 
@@ -240,6 +260,7 @@ function(qt_internal_add_3rdparty_library target)
         MOC_OPTIONS ${arg_MOC_OPTIONS}
         ENABLE_AUTOGEN_TOOLS ${arg_ENABLE_AUTOGEN_TOOLS}
         DISABLE_AUTOGEN_TOOLS ${arg_DISABLE_AUTOGEN_TOOLS}
+        NO_UNITY_BUILD
     )
 
     if(NOT BUILD_SHARED_LIBS OR arg_INSTALL)
diff --git a/cmake/QtBaseGlobalTargets.cmake b/cmake/QtBaseGlobalTargets.cmake
index b3eea3006f..6a885fc4ce 100644
--- a/cmake/QtBaseGlobalTargets.cmake
+++ b/cmake/QtBaseGlobalTargets.cmake
@@ -263,6 +263,7 @@ qt_copy_or_install(FILES
                    cmake/QtPostProcess.cmake
                    cmake/QtPostProcessHelpers.cmake
                    cmake/QtPrecompiledHeadersHelpers.cmake
+                   cmake/QtUnityBuildHelpers.cmake
                    cmake/QtPriHelpers.cmake
                    cmake/QtPrlHelpers.cmake
                    cmake/QtPlatformTargetHelpers.cmake
diff --git a/cmake/QtBuild.cmake b/cmake/QtBuild.cmake
index 13772fce86..6bf4a9edd5 100644
--- a/cmake/QtBuild.cmake
+++ b/cmake/QtBuild.cmake
@@ -459,6 +459,7 @@ set(__default_private_args
     DISABLE_AUTOGEN_TOOLS
     ENABLE_AUTOGEN_TOOLS
     PLUGIN_TYPES
+    NO_UNITY_BUILD_SOURCES
 )
 set(__default_public_args
     PUBLIC_LIBRARIES
@@ -487,6 +488,7 @@ set(__qt_internal_add_executable_optional_args
     DELAY_RC
     DELAY_TARGET_INFO
     QT_APP
+    NO_UNITY_BUILD
 )
 set(__qt_internal_add_executable_single_args
     CORE_LIBRARY
@@ -520,6 +522,7 @@ include(QtModuleHelpers)
 include(QtNoLinkTargetHelpers)
 include(QtPluginHelpers)
 include(QtPrecompiledHeadersHelpers)
+include(QtUnityBuildHelpers)
 include(QtPkgConfigHelpers)
 include(QtPriHelpers)
 include(QtPrlHelpers)
diff --git a/cmake/QtExecutableHelpers.cmake b/cmake/QtExecutableHelpers.cmake
index 91ac2cfeb6..bd41c474eb 100644
--- a/cmake/QtExecutableHelpers.cmake
+++ b/cmake/QtExecutableHelpers.cmake
@@ -110,6 +110,12 @@ function(qt_internal_add_executable name)
             "removed in a future Qt version. Use the LIBRARIES option instead.")
     endif()
 
+    if(arg_NO_UNITY_BUILD)
+        set(arg_NO_UNITY_BUILD NO_UNITY_BUILD)
+    else()
+        set(arg_NO_UNITY_BUILD "")
+    endif()
+
     qt_internal_extend_target("${name}"
         SOURCES ${arg_SOURCES}
         INCLUDE_DIRECTORIES ${private_includes}
@@ -128,6 +134,8 @@ function(qt_internal_add_executable name)
         MOC_OPTIONS ${arg_MOC_OPTIONS}
         ENABLE_AUTOGEN_TOOLS ${arg_ENABLE_AUTOGEN_TOOLS}
         DISABLE_AUTOGEN_TOOLS ${arg_DISABLE_AUTOGEN_TOOLS}
+        NO_UNITY_BUILD_SOURCES ${arg_NO_UNITY_BUILD_SOURCES}
+        ${arg_NO_UNITY_BUILD}
     )
     set_target_properties("${name}" PROPERTIES
         RUNTIME_OUTPUT_DIRECTORY "${arg_OUTPUT_DIRECTORY}"
diff --git a/cmake/QtModuleHelpers.cmake b/cmake/QtModuleHelpers.cmake
index cbe8defaf8..f7c5c4b11b 100644
--- a/cmake/QtModuleHelpers.cmake
+++ b/cmake/QtModuleHelpers.cmake
@@ -18,6 +18,7 @@ macro(qt_internal_get_internal_add_module_keywords option_args single_args multi
         NO_HEADERSCLEAN_CHECK
         GENERATE_CPP_EXPORTS
         GENERATE_PRIVATE_CPP_EXPORTS
+        NO_UNITY_BUILD
     )
     set(${single_args}
         MODULE_INCLUDE_NAME
@@ -572,6 +573,12 @@ function(qt_internal_add_module target)
 
     qt_internal_add_repo_local_defines("${target}")
 
+    if(arg_NO_UNITY_BUILD)
+        set(arg_NO_UNITY_BUILD NO_UNITY_BUILD)
+    else()
+        set(arg_NO_UNITY_BUILD "")
+    endif()
+
     if(NOT arg_EXTERNAL_HEADERS)
         set(arg_EXTERNAL_HEADERS "")
     endif()
@@ -607,6 +614,8 @@ function(qt_internal_add_module target)
         DISABLE_AUTOGEN_TOOLS ${arg_DISABLE_AUTOGEN_TOOLS}
         PRECOMPILED_HEADER ${arg_PRECOMPILED_HEADER}
         NO_PCH_SOURCES ${arg_NO_PCH_SOURCES}
+        NO_UNITY_BUILD_SOURCES ${arg_NO_UNITY_BUILD_SOURCES}
+        ${arg_NO_UNITY_BUILD}
     )
 
     # The public module define is not meant to be used when building the module itself,
diff --git a/cmake/QtPluginHelpers.cmake b/cmake/QtPluginHelpers.cmake
index 0e5612d70b..3da75168aa 100644
--- a/cmake/QtPluginHelpers.cmake
+++ b/cmake/QtPluginHelpers.cmake
@@ -8,6 +8,7 @@ macro(qt_internal_get_internal_add_plugin_keywords option_args single_args multi
         EXCEPTIONS
         ALLOW_UNDEFINED_SYMBOLS
         SKIP_INSTALL
+        NO_UNITY_BUILD
     )
     set(${single_args}
         OUTPUT_DIRECTORY
@@ -305,6 +306,12 @@ function(qt_internal_add_plugin target)
         endif()
     endif()
 
+    if(arg_NO_UNITY_BUILD)
+        set(arg_NO_UNITY_BUILD NO_UNITY_BUILD)
+    else()
+        set(arg_NO_UNITY_BUILD "")
+    endif()
+
     set_property(TARGET "${target}" PROPERTY QT_DEFAULT_PLUGIN "${_default_plugin}")
     set_property(TARGET "${target}" APPEND PROPERTY EXPORT_PROPERTIES "QT_PLUGIN_CLASS_NAME;QT_PLUGIN_TYPE;QT_MODULE;QT_DEFAULT_PLUGIN")
 
@@ -347,6 +354,8 @@ function(qt_internal_add_plugin target)
         MOC_OPTIONS ${arg_MOC_OPTIONS}
         ENABLE_AUTOGEN_TOOLS ${arg_ENABLE_AUTOGEN_TOOLS}
         DISABLE_AUTOGEN_TOOLS ${arg_DISABLE_AUTOGEN_TOOLS}
+        NO_UNITY_BUILD_SOURCES ${arg_NO_UNITY_BUILD_SOURCES}
+        ${arg_NO_UNITY_BUILD}
     )
 
     qt_internal_add_repo_local_defines("${target}")
diff --git a/cmake/QtPrecompiledHeadersHelpers.cmake b/cmake/QtPrecompiledHeadersHelpers.cmake
index 08aa0bcc01..fe38413407 100644
--- a/cmake/QtPrecompiledHeadersHelpers.cmake
+++ b/cmake/QtPrecompiledHeadersHelpers.cmake
@@ -19,7 +19,9 @@ endfunction()
 
 function(qt_update_ignore_pch_source target sources)
     if (sources)
-        set_source_files_properties(${sources} PROPERTIES SKIP_PRECOMPILE_HEADERS ON)
+        set_source_files_properties(${sources} PROPERTIES
+                                               SKIP_PRECOMPILE_HEADERS ON
+                                               SKIP_UNITY_BUILD_INCLUSION ON)
     endif()
 endfunction()
 
diff --git a/cmake/QtSimdHelpers.cmake b/cmake/QtSimdHelpers.cmake
index 6d9d6d46fe..1e77bf449f 100644
--- a/cmake/QtSimdHelpers.cmake
+++ b/cmake/QtSimdHelpers.cmake
@@ -98,7 +98,9 @@ function(qt_internal_add_simd_part target)
                 ${arg_COMPILE_FLAGS}
             )
         endforeach()
-        set_source_files_properties(${arg_SOURCES} PROPERTIES SKIP_PRECOMPILE_HEADERS TRUE)
+        set_source_files_properties(${arg_SOURCES} PROPERTIES
+                                                   SKIP_PRECOMPILE_HEADERS TRUE
+                                                   SKIP_UNITY_BUILD_INCLUSION TRUE)
         target_sources(${target} PRIVATE ${arg_SOURCES})
     else()
         if(QT_CMAKE_DEBUG_EXTEND_TARGET)
diff --git a/cmake/QtTargetHelpers.cmake b/cmake/QtTargetHelpers.cmake
index 700b32aa3c..a98e940885 100644
--- a/cmake/QtTargetHelpers.cmake
+++ b/cmake/QtTargetHelpers.cmake
@@ -35,7 +35,9 @@ function(qt_internal_extend_target target)
         return()
     endif()
 
-    set(option_args "")
+    set(option_args
+        NO_UNITY_BUILD
+    )
     set(single_args
         PRECOMPILED_HEADER
     )
@@ -211,6 +213,7 @@ function(qt_internal_extend_target target)
 
         qt_update_precompiled_header("${target}" "${arg_PRECOMPILED_HEADER}")
         qt_update_ignore_pch_source("${target}" "${arg_NO_PCH_SOURCES}")
+        qt_update_ignore_unity_build_sources("${target}" "${arg_NO_UNITY_BUILD_SOURCES}")
         ## Ignore objective-c files for PCH (not supported atm)
         qt_ignore_pch_obj_c_sources("${target}" "${arg_SOURCES}")
 
@@ -230,6 +233,10 @@ function(qt_internal_extend_target target)
         set_property(TARGET ${target} APPEND PROPERTY
             ${sources_property} "${arg_CONDITION_INDEPENDENT_SOURCES}")
     endif()
+
+    if(arg_NO_UNITY_BUILD)
+        set_target_properties(${target} PROPERTIES UNITY_BUILD OFF)
+    endif()
 endfunction()
 
 function(qt_is_imported_target target out_var)
diff --git a/cmake/QtTestHelpers.cmake b/cmake/QtTestHelpers.cmake
index 463229abd5..725c3fa0be 100644
--- a/cmake/QtTestHelpers.cmake
+++ b/cmake/QtTestHelpers.cmake
@@ -37,6 +37,7 @@ function(qt_internal_add_benchmark target)
 
     qt_internal_add_executable(${target}
         NO_INSTALL # we don't install benchmarks
+        NO_UNITY_BUILD # excluded by default
         OUTPUT_DIRECTORY "${arg_OUTPUT_DIRECTORY}" # avoid polluting bin directory
         ${exec_args}
     )
@@ -121,6 +122,7 @@ function(qt_internal_add_manual_test target)
 
     qt_internal_add_executable(${target}
         NO_INSTALL # we don't install benchmarks
+        NO_UNITY_BUILD
         OUTPUT_DIRECTORY "${arg_OUTPUT_DIRECTORY}" # avoid polluting bin directory
         ${exec_args}
     )
@@ -362,7 +364,9 @@ function(qt_internal_add_test_to_batch batch_name name)
         LINK_OPTIONS ${arg_LINK_OPTIONS}
         MOC_OPTIONS ${arg_MOC_OPTIONS}
         ENABLE_AUTOGEN_TOOLS ${arg_ENABLE_AUTOGEN_TOOLS}
-        DISABLE_AUTOGEN_TOOLS ${arg_DISABLE_AUTOGEN_TOOLS})
+        DISABLE_AUTOGEN_TOOLS ${arg_DISABLE_AUTOGEN_TOOLS}
+        NO_UNITY_BUILD # Tests should not be built using UNITY_BUILD
+        )
 
     foreach(source ${arg_SOURCES})
         # We define the test name which is later used to launch this test using
@@ -527,6 +531,7 @@ function(qt_internal_add_test name)
             MOC_OPTIONS ${arg_MOC_OPTIONS}
             ENABLE_AUTOGEN_TOOLS ${arg_ENABLE_AUTOGEN_TOOLS}
             DISABLE_AUTOGEN_TOOLS ${arg_DISABLE_AUTOGEN_TOOLS}
+            NO_UNITY_BUILD  # Tests should not be built using UNITY_BUILD
         )
 
         qt_internal_add_repo_local_defines(${name})
@@ -908,7 +913,9 @@ function(qt_internal_add_test_helper name)
         endif()
     endif()
 
-    qt_internal_add_executable("${name}" NO_INSTALL ${extra_args_to_pass} ${forward_args})
+    qt_internal_add_executable("${name}" NO_INSTALL
+                                         NO_UNITY_BUILD # excluded by default
+                                         ${extra_args_to_pass} ${forward_args})
 
     # Disable the QT_NO_NARROWING_CONVERSIONS_IN_CONNECT define for test helpers
     qt_internal_undefine_global_definition(${name} QT_NO_NARROWING_CONVERSIONS_IN_CONNECT)
diff --git a/cmake/QtToolHelpers.cmake b/cmake/QtToolHelpers.cmake
index 3f97e5ac4a..92bb3dc6d1 100644
--- a/cmake/QtToolHelpers.cmake
+++ b/cmake/QtToolHelpers.cmake
@@ -37,7 +37,12 @@
 #         linked to the executable target by default.
 function(qt_internal_add_tool target_name)
     qt_tool_target_to_name(name ${target_name})
-    set(option_keywords NO_INSTALL USER_FACING INSTALL_VERSIONED_LINK EXCEPTIONS)
+    set(option_keywords
+        NO_INSTALL
+        USER_FACING
+        INSTALL_VERSIONED_LINK
+        EXCEPTIONS
+        NO_UNITY_BUILD)
     set(one_value_keywords
         TOOLS_TARGET
         INSTALL_DIR
@@ -88,6 +93,12 @@ function(qt_internal_add_tool target_name)
 
     qt_internal_library_deprecation_level(deprecation_define)
 
+    if(arg_NO_UNITY_BUILD)
+        set(arg_NO_UNITY_BUILD NO_UNITY_BUILD)
+    else()
+        set(arg_NO_UNITY_BUILD "")
+    endif()
+
     qt_internal_add_executable("${target_name}"
         OUTPUT_DIRECTORY "${output_dir}"
         ${exceptions}
@@ -113,6 +124,8 @@ function(qt_internal_add_tool target_name)
         TARGET_DESCRIPTION "${arg_TARGET_DESCRIPTION}"
         TARGET_COMPANY "${arg_TARGET_COMPANY}"
         TARGET_COPYRIGHT "${arg_TARGET_COPYRIGHT}"
+        NO_UNITY_BUILD_SOURCES "${arg_NO_UNITY_BUILD_SOURCES}"
+        ${arg_NO_UNITY_BUILD}
     )
     qt_internal_add_target_aliases("${target_name}")
     _qt_internal_apply_strict_cpp("${target_name}")
diff --git a/cmake/QtUnityBuildHelpers.cmake b/cmake/QtUnityBuildHelpers.cmake
new file mode 100644
index 0000000000..41062b027c
--- /dev/null
+++ b/cmake/QtUnityBuildHelpers.cmake
@@ -0,0 +1,8 @@
+# Copyright (C) 2023 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+function(qt_update_ignore_unity_build_sources target sources)
+    if (sources)
+        set_source_files_properties(${sources} PROPERTIES SKIP_UNITY_BUILD_INCLUSION ON)
+    endif()
+endfunction()