build: PROGRAM, QUIET, and REQUIRED options added for enable_iwyu()

cmake/include-what-you-use.cmake

@@ -30,14 +30,6 @@ endif()
 
 set(IWYU_VERBOSITY_LEVEL 3 CACHE STRING "IWYU verbosity level (the higher the level, the more output)")
 
-macro(_find_iwyu)
-    find_program(_iwyu_path NAMES "include-what-you-use")
-    if(NOT _iwyu_path)
-        message(FATAL_ERROR "'include-what-you-use' executable not found!")
-        return()
-    endif()
-endmacro()
-
 macro(_iwyu_args_append arg)
     list(APPEND _iwyu_args "-Xiwyu" "${arg}")
 endmacro()
@@ -48,9 +40,16 @@ macro(_iwyu_args_append_if_present option arg)
     endif()
 endmacro()
 
-macro(_process_iwyu_arguments offset)
+macro(_enable_iwyu_failed log_postfix)
-    set(_options NO_DEFAULT_MAPPINGS PCH_IN_CODE TRANSITIVE_INCLUDES_ONLY NO_COMMENTS NO_FORWARD_DECLARATIONS CXX17_NAMESPACES QUOTED_INCLUDES_FIRST)
+    if(NOT _enable_iwyu_QUIET)
-    set(_one_value_args MAPPING_FILE MAX_LINE_LENGTH)
+        message(STATUS "Enabling include-what-you-use${log_postfix} - failed")
+    endif()
+    return()
+endmacro()
+
+macro(_process_iwyu_arguments offset log_postfix)
+    set(_options QUIET REQUIRED NO_DEFAULT_MAPPINGS PCH_IN_CODE TRANSITIVE_INCLUDES_ONLY NO_COMMENTS NO_FORWARD_DECLARATIONS CXX17_NAMESPACES QUOTED_INCLUDES_FIRST)
+    set(_one_value_args PROGRAM MAPPING_FILE MAX_LINE_LENGTH)
     set(_multi_value_args KEEP)
     cmake_parse_arguments(PARSE_ARGV ${offset} _enable_iwyu "${_options}" "${_one_value_args}" "${_multi_value_args}")
 
@@ -63,6 +62,32 @@ macro(_process_iwyu_arguments offset)
         message(FATAL_ERROR "No value provided for '${_enable_iwyu_KEYWORDS_MISSING_VALUES}'")
     endif()
 
+    if(NOT _enable_iwyu_QUIET)
+        message(STATUS "Enabling include-what-you-use${log_postfix}")
+    endif()
+
+    if(${_enable_iwyu_REQUIRED})
+        set(_error_log_level FATAL_ERROR)
+    elseif(NOT _enable_iwyu_QUIET)
+        set(_error_log_level STATUS)
+    endif()
+
+    if(NOT DEFINED _enable_iwyu_PROGRAM)
+        set(_enable_iwyu_PROGRAM include-what-you-use)
+    endif()
+
+    find_program(IWYU_PATH ${_enable_iwyu_PROGRAM})
+    if(IWYU_PATH)
+        if(NOT _enable_iwyu_QUIET)
+            message(STATUS "  Executable: ${IWYU_PATH}")
+        endif()
+    else()
+        if(DEFINED _error_log_level)
+            message(${_error_log_level} "  '${_enable_iwyu_PROGRAM}' executable was not found")
+        endif()
+        _enable_iwyu_failed("${log_postfix}")
+    endif()
+
     if(_enable_iwyu_KEEP)
         foreach(_pattern ${_enable_iwyu_KEEP})
             _iwyu_args_append("--keep=${_pattern}")
@@ -92,10 +117,36 @@ macro(_process_iwyu_arguments offset)
     _iwyu_args_append_if_present(QUOTED_INCLUDES_FIRST "--quoted_includes_first")
 
     _iwyu_args_append("--verbose=${IWYU_VERBOSITY_LEVEL}")
+
+    if(NOT _enable_iwyu_QUIET)
+        message(STATUS "  Arguments: ${_iwyu_args}")
+        message(STATUS "Enabling include-what-you-use${log_postfix} - done")
+    endif()
 endmacro()
 
+#
+# enable_iwyu([PROGRAM]                     # include-what-you-use by default
+#             [QUIET] [REQUIRED]
+#             [KEEP patterns...]
+#             [MAPPING_FILE file]
+#             [NO_DEFAULT_MAPPINGS]
+#             [PCH_IN_CODE]
+#             [TRANSITIVE_INCLUDES_ONLY]
+#             [MAX_LINE_LENGTH length]
+#             [NO_COMMENTS]
+#             [NO_FORWARD_DECLARATIONS]
+#             [CXX17_NAMESPACES]
+#             [QUOTED_INCLUDES_FIRST])
+#
+function(enable_iwyu)
+    _process_iwyu_arguments(0 "")
+    set(CMAKE_CXX_INCLUDE_WHAT_YOU_USE "${_iwyu_path};${_iwyu_args}" PARENT_SCOPE)
+endfunction()
+
 #
 # enable_target_iwyu(TargetName
+#                    [PROGRAM]                     # include-what-you-use by default
+#                    [QUIET] [REQUIRED]
 #                    [KEEP pattern...]
 #                    [MAPPING_FILE file]
 #                    [NO_DEFAULT_MAPPINGS]
@@ -108,39 +159,8 @@ endmacro()
 #                    [QUOTED_INCLUDES_FIRST])
 #
 function(enable_target_iwyu target)
-    _find_iwyu()
+    _process_iwyu_arguments(1 " for '${target}'")
-    _process_iwyu_arguments(1)
-
-    message(STATUS "Enabling include-what-you-use for '${target}'")
-    message(STATUS "  Path: ${_iwyu_path}")
-    message(STATUS "  Arguments: ${_iwyu_args}")
-    message(STATUS "Enabling include-what-you-use for '${target}' - done")
-
     set_target_properties(${target} PROPERTIES
         CXX_INCLUDE_WHAT_YOU_USE "${_iwyu_path};${_iwyu_args}"
     )
 endfunction()
-
-#
-# enable_target_iwyu([KEEP patterns...]
-#                    [MAPPING_FILE file]
-#                    [NO_DEFAULT_MAPPINGS]
-#                    [PCH_IN_CODE]
-#                    [TRANSITIVE_INCLUDES_ONLY]
-#                    [MAX_LINE_LENGTH length]
-#                    [NO_COMMENTS]
-#                    [NO_FORWARD_DECLARATIONS]
-#                    [CXX17_NAMESPACES]
-#                    [QUOTED_INCLUDES_FIRST])
-#
-function(enable_iwyu)
-    _find_iwyu()
-    _process_iwyu_arguments(0)
-
-    message(STATUS "Enabling include-what-you-use")
-    message(STATUS "  Path: ${_iwyu_path}")
-    message(STATUS "  Arguments: ${_iwyu_args}")
-    message(STATUS "Enabling include-what-you-use - done")
-
-    set(CMAKE_CXX_INCLUDE_WHAT_YOU_USE "${_iwyu_path};${_iwyu_args}" PARENT_SCOPE)
-endfunction()