Add support for benchmark conversion

Convert benchmark executables to add_qt_benchmark().

Currently add_qt_benchmark just calls add_qt_executable() and
ensures that it they build under CMAKE_CURRENT_BUILD_DIR and do not
install.

Add QT_BUILD_BENCHMARKS option to enable/disable building of benchmarks.

Change-Id: Id0bc676698d21d50048d97d9abef51d92ccb6638
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

cmake/QtBuild.cmake

@@ -2351,6 +2351,38 @@ function(add_qt_executable name)
     endif()
 endfunction()
 
+# Simple wrapper around add_qt_executable for benchmarks which insure that
+# the binary is built under ${CMAKE_CURRENT_BINARY_DIR} and never installed.
+# See add_qt_executable() for more details.
+function(add_qt_benchmark target)
+
+    qt_parse_all_arguments(arg "add_qt_benchmark"
+        "${__add_qt_executable_optional_args}"
+        "${__add_qt_executable_single_args}"
+        "${__add_qt_executable_multi_args}"
+        ${ARGN}
+    )
+
+    qt_remove_args(exec_args
+        ARGS_TO_REMOVE
+            ${target}
+            OUTPUT_DIRECTORY
+            INSTALL_DIRECTORY
+        ALL_ARGS
+            "${__add_qt_executable_optional_args}"
+            "${__add_qt_executable_single_args}"
+            "${__add_qt_executable_multi_args}"
+        ARGS
+            ${ARGV}
+    )
+
+    add_qt_executable(${target}
+        NO_INSTALL # we don't install benchmarks
+        OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}" # avoid polluting bin directory
+        ${exec_args}
+    )
+
+endfunction()
 
 # This function creates a CMake test target with the specified name for use with CTest.
 function(add_qt_test name)

cmake/QtBuildInternals/QtBuildInternalsConfig.cmake

@@ -159,7 +159,7 @@ macro(qt_build_tests)
     if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/auto/CMakeLists.txt")
         add_subdirectory(auto)
     endif()
-    if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/benchmarks/CMakeLists.txt")
+    if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/benchmarks/CMakeLists.txt" AND QT_BUILD_BENCHMARKS)
         add_subdirectory(benchmarks)
     endif()
 endmacro()

cmake/QtSetup.cmake

@@ -73,8 +73,16 @@ if(FEATURE_developer_build)
         set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
     endif()
     set(QT_BUILD_TESTING ON)
+    set(__build_benchmarks ON)
+
+    # Disable benchmarks for single configuration generators which do not build
+    # with release configuration.
+    if (CMAKE_BUILD_TYPE AND NOT CMAKE_BUILD_TYPE STREQUAL Release)
+        set(__build_benchmarks OFF)
+    endif()
 else()
     set(QT_BUILD_TESTING OFF)
+    set(__build_benchmarks OFF)
 endif()
 
 ## Set up testing
@@ -85,6 +93,9 @@ enable_testing()
 # Set up building of examples.
 option(BUILD_EXAMPLES "Build Qt examples" ON)
 
+# Build Benchmarks
+option(QT_BUILD_BENCHMARKS "Build Qt Benchmarks" ${__build_benchmarks})
+
 ## Android platform settings
 if(ANDROID)
     include(QtPlatformAndroid)

util/cmake/pro2cmake.py

@@ -233,6 +233,16 @@ def is_config_test_project(project_file_path: str = "") -> bool:
     )
 
 
+def is_benchmark_project(project_file_path: str = "") -> bool:
+    qmake_conf_path = find_qmake_conf(project_file_path)
+    qmake_conf_dir_path = os.path.dirname(qmake_conf_path)
+
+    project_relative_path = os.path.relpath(project_file_path, qmake_conf_dir_path)
+    # If the project file is found in a subdir called 'tests/benchmarks'
+    # relative to the repo source dir, then it must be benchmark
+    return project_relative_path.startswith("tests/benchmarks")
+
+
 @lru_cache(maxsize=None)
 def find_qmake_conf(project_file_path: str = "") -> str:
     if not os.path.isabs(project_file_path):
@@ -2661,22 +2671,29 @@ def write_binary(cm_fh: IO[str], scope: Scope, gui: bool = False, *, indent: int
     binary_name = scope.TARGET
     assert binary_name
 
+    is_benchmark = is_benchmark_project(scope.file_absolute_path)
+
     is_qt_test_helper = "qt_test_helper" in scope.get("_LOADED")
 
     extra = ["GUI"] if gui and not is_qt_test_helper else []
     cmake_function_call = "add_qt_executable"
+    extra_keys = []
 
     if is_qt_test_helper:
         binary_name += "_helper"
         cmake_function_call = "add_qt_test_helper"
 
-    target_path = scope.get_string("target.path")
-    if target_path:
-        target_path = replace_path_constants(target_path, scope)
-        if not scope.get("DESTDIR"):
-            extra.append(f'OUTPUT_DIRECTORY "{target_path}"')
-        if "target" in scope.get("INSTALLS"):
-            extra.append(f'INSTALL_DIRECTORY "{target_path}"')
+    if is_benchmark:
+        cmake_function_call = "add_qt_benchmark"
+    else:
+        extra_keys = ["target.path", "INSTALLS"]
+        target_path = scope.get_string("target.path")
+        if target_path:
+            target_path = replace_path_constants(target_path, scope)
+            if not scope.get("DESTDIR"):
+                extra.append(f'OUTPUT_DIRECTORY "{target_path}"')
+            if "target" in scope.get("INSTALLS"):
+                extra.append(f'INSTALL_DIRECTORY "{target_path}"')
 
     write_main_part(
         cm_fh,
@@ -2687,7 +2704,7 @@ def write_binary(cm_fh: IO[str], scope: Scope, gui: bool = False, *, indent: int
         extra_lines=extra,
         indent=indent,
         known_libraries={"Qt::Core"},
-        extra_keys=["target.path", "INSTALLS"],
+        extra_keys=extra_keys,
     )
 
     return binary_name