From 8746aa57aec43cf8670789a33d98a8bd49bf4cfe Mon Sep 17 00:00:00 2001
From: Michael Fabian 'Xaymar' Dirks <info@xaymar.com>
Date: Sat, 18 Apr 2020 16:17:15 +0200
Subject: [PATCH] clang-tidy: Compile Command Database generation and
 clang-tidy

Adds support for clang-tidy by the use of a manually generated compile command database. This is likely not full functional yet, so more tests might have to be done on different platforms and compilers.
---
 Clang.cmake | 379 ++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 352 insertions(+), 27 deletions(-)

diff --git a/Clang.cmake b/Clang.cmake
index d4344cf..b724eb1 100644
--- a/Clang.cmake
+++ b/Clang.cmake
@@ -1,9 +1,224 @@
 set(CLANG_PATH "" CACHE PATH "Path to Clang Toolset (if not in environment)")
 
+function(string_escape)
+	cmake_parse_arguments(
+		PARSE_ARGV 0
+		_ARGS
+		""
+		"OUTPUT;INPUT"
+		""
+	)
+
+	set(_el "${_ARGS_INPUT}")
+	string(REPLACE "\\" "\\\\" _el "${_el}")
+	string(REPLACE "\"" "\\\"" _el "${_el}")
+	set(${_ARGS_OUTPUT} "${_el}" PARENT_SCOPE)
+endfunction()
+
+function(string_append_escaped)
+	cmake_parse_arguments(
+		PARSE_ARGV 0
+		_ARGS
+		""
+		"OUTPUT;INPUT"
+		""
+	)
+
+	set(_el "${_ARGS_INPUT}")
+	if(_el)
+		string_escape(OUTPUT _el INPUT "${_el}")
+		set(${_ARGS_OUTPUT} "${${_ARGS_OUTPUT}}${_el}" PARENT_SCOPE)
+	endif()
+endfunction()
+
+function(string_append_target_includes)
+	cmake_parse_arguments(
+		PARSE_ARGV 0
+		_ARGS
+		"LINKED"
+		"OUTPUT;PREFIX;TARGET"
+		""
+	)
+
+	set(_out "")
+	if(TARGET ${_ARGS_TARGET})
+		get_target_property(target_type ${_ARGS_TARGET} TYPE)
+		if(
+			(${target_type} STREQUAL "MODULE_LIBRARY") OR
+			(${target_type} STREQUAL "STATIC_LIBRARY") OR
+			(${target_type} STREQUAL "SHARED_LIBRARY") OR
+			(${target_type} STREQUAL "EXECUTABLE")
+		)
+			set(prop "$<TARGET_PROPERTY:${_ARGS_TARGET},INCLUDE_DIRECTORIES>")
+			set(test "$<$<BOOL:${prop}>:${_ARGS_PREFIX}$<JOIN:${prop}, ${_ARGS_PREFIX}>>")
+			set(_out "${_out}${test} ")
+			set(prop "$<TARGET_PROPERTY:${_ARGS_TARGET},INTERFACE_INCLUDE_DIRECTORIES>")
+			set(test "$<$<BOOL:${prop}>:${_ARGS_PREFIX}$<JOIN:${prop}, ${_ARGS_PREFIX}>>")
+			set(_out "${_out}${test} ")
+			set(prop "$<TARGET_PROPERTY:${_ARGS_TARGET},INTERFACE_SYSTEM_INCLUDE_DIRECTORIES>")
+			set(test "$<$<BOOL:${prop}>:${_ARGS_PREFIX}$<JOIN:${prop}, ${_ARGS_PREFIX}>>")
+			set(_out "${_out}${test} ")
+			if(NOT _ARGS_LINKED)
+				# Scan linked libraries as well.
+				get_target_property(_els ${_target} LINK_LIBRARIES)
+				foreach(_lib ${_els})
+					#string_append_target_includes(LINKED TARGET "${_lib}" OUTPUT "_out" PREFIX "${_ARGS_PREFIX}")
+				endforeach()
+			endif()
+		elseif((${target_type} STREQUAL "INTERFACE_LIBRARY"))
+			set(prop "$<TARGET_PROPERTY:${_ARGS_TARGET},INTERFACE_INCLUDE_DIRECTORIES>")
+			set(test "$<$<BOOL:${prop}>:${_ARGS_PREFIX}$<JOIN:${prop}, ${_ARGS_PREFIX}>>")
+			set(_out "${_out}${test} ")
+		else()
+			message("clang: Unsupported Target type '${target_type}', please open an issue for this.")
+		endif()
+	endif()
+
+	set(${_ARGS_OUTPUT} "${${_ARGS_OUTPUT}}${_out}" PARENT_SCOPE)
+endfunction()
+
+function(generate_compile_commands_json)
+	cmake_parse_arguments(
+		PARSE_ARGV 0
+		_ARGS
+		""
+		"REGEX"
+		"TARGETS"
+	)
+
+	set(COMPILER_TAG "")
+	if((CMAKE_C_COMPILER_ID STREQUAL "MSVC") AND (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC"))
+		set(COMPILER_TAG "MSVC")
+		set(COMPILER_INCLUDE_PREFIX "/I")
+		set(COMPILER_DEFINE_PREFIX "/D")
+	elseif((CMAKE_C_COMPILER_ID STREQUAL "GNU") AND (CMAKE_CXX_COMPILER_ID STREQUAL "GNU"))
+		set(COMPILER_TAG "GNU")
+		set(COMPILER_INCLUDE_PREFIX "-I")
+		set(COMPILER_DEFINE_PREFIX "-D")
+	elseif((CMAKE_C_COMPILER_ID STREQUAL "Clang") AND (CMAKE_CXX_COMPILER_ID STREQUAL "Clang"))
+		set(COMPILER_TAG "CLANG") # Compatible with GNU
+		set(COMPILER_INCLUDE_PREFIX "-I")
+		set(COMPILER_DEFINE_PREFIX "-D")
+	else()
+		message("clang-tidy: C ID '${CMAKE_C_COMPILER_ID}'")
+		message("clang-tidy: C Version '${CMAKE_C_COMPILER_VERSION}'")
+		message("clang-tidy: C++ ID '${CMAKE_CXX_COMPILER_ID}'")
+		message("clang-tidy: C++ Version '${CMAKE_CXX_COMPILER_VERSION}'")
+		message(FATAL_ERROR "clang-tidy: Current Compiler is not yet supported, please open an issue for it.")
+	endif()
+
+	# Default Filter
+	if(NOT _ARGS_REGEX)
+		set(_ARGS_REGEX "\.(h|hpp|c|cpp)$")
+	endif()
+
+	foreach(_target ${_ARGS_TARGETS})
+		set(COMPILE_COMMAND_JSON "")
+
+		# Source Directory
+		get_target_property(target_source_dir_rel ${_target} SOURCE_DIR)
+		get_filename_component(target_source_dir ${target_source_dir_rel} ABSOLUTE)
+		unset(target_source_dir_rel)
+
+		# Binary Directory
+		get_target_property(target_binary_dir_rel ${_target} BINARY_DIR)
+		get_filename_component(target_binary_dir ${target_binary_dir_rel} ABSOLUTE)
+		unset(target_binary_dir_rel)
+
+		# Sources
+		get_target_property(_els ${_target} SOURCES)
+		set(target_sources "")
+		foreach(_el ${_els})
+			get_filename_component(_el "${_el}" ABSOLUTE)
+			list(APPEND target_sources "${_el}")
+		endforeach()
+		list(FILTER target_sources INCLUDE REGEX "${_ARGS_REGEX}")
+
+		# Combine Compiler String
+		set(COMPILER_OPTIONS "")
+		## Compiler Options
+		get_target_property(_els ${_target} COMPILE_OPTIONS)
+		foreach(_el ${_els})
+			string_append_escaped(OUTPUT COMPILER_OPTIONS INPUT "${_el} ")
+		endforeach()
+		string(APPEND COMPILER_OPTIONS "${CMAKE_CXX_FLAGS} ${CMAKE_C_FLAGS} ")
+		## C++ Standard
+		get_target_property(_el ${_target} CXX_STANDARD)
+		if(COMPILER_TAG STREQUAL "MSVC")
+			if(${MSVC_VERSION} LESS "1920")
+				message(FATAL_ERROR "clang-tidy: Current Compiler is not yet supported, please open an issue for it.")
+			else()
+				if((_el EQUAL 98) OR (_el EQUAL 11))
+					# Nothing to do, this is the default.
+				elseif(_el EQUAL 14)
+					string(APPEND COMPILER_OPTIONS "/std:c++14 ")
+				elseif(_el EQUAL 17)
+					string(APPEND COMPILER_OPTIONS "/std:c++17 ")
+				elseif(_el EQUAL 20)
+					string(APPEND COMPILER_OPTIONS "/std:c++latest ")
+				endif()
+			endif()
+		elseif((COMPILER_TAG STREQUAL "CLANG") OR (COMPILER_TAG STREQUAL "GNU"))
+			if(_el EQUAL 98)
+				string(APPEND COMPILER_OPTIONS "-std=c++98 ")
+			elseif(_el EQUAL 11)
+				string(APPEND COMPILER_OPTIONS "-std=c++11 ")
+			elseif(_el EQUAL 14)
+				string(APPEND COMPILER_OPTIONS "-std=c++14 ")
+			elseif(_el EQUAL 17)
+				string(APPEND COMPILER_OPTIONS "-std=c++17 ")
+			elseif(_el EQUAL 20)
+				if((COMPILER_TAG STREQUAL "CLANG") OR (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 9))
+					string(APPEND COMPILER_OPTIONS "-std=c++20 ")
+				else()
+					string(APPEND COMPILER_OPTIONS "-std=c++2a ")
+				endif()
+			endif()
+		endif()
+		## Definitions
+		get_target_property(_els ${_target} COMPILE_DEFINITIONS)
+		foreach(_el ${_els})
+			string_append_escaped(OUTPUT COMPILER_OPTIONS INPUT "${COMPILER_DEFINE_PREFIX}${_el} ")
+		endforeach()
+		## Includes
+		string_append_target_includes(TARGET ${_target} PREFIX ${COMPILER_INCLUDE_PREFIX} OUTPUT COMPILER_OPTIONS)
+
+		# Create Compilation Database
+		set(target_compile_db  "${target_binary_dir}/compile_commands.json")
+		string(APPEND COMPILE_COMMAND_JSON "[\n")
+		foreach(_el ${target_sources})
+			file(TO_NATIVE_PATH "${_el}" _el)
+			string(REPLACE "\\" "\\\\" _el "${_el}")
+			string(REPLACE "\"" "\\\"" _el "${_el}")
+
+			string(APPEND COMPILE_COMMAND_JSON "\t{\n")
+			string(APPEND COMPILE_COMMAND_JSON "\t\t\"directory\": \"${target_binary_dir}\",\n")
+			string(APPEND COMPILE_COMMAND_JSON "\t\t\"file\": \"${_el}\",\n")
+			if(MSVC)
+				string(APPEND COMPILE_COMMAND_JSON "\t\t\"command\": \"cl ")
+			else()
+				string(APPEND COMPILE_COMMAND_JSON "\t\t\"command\": \"cc ")
+			endif()
+
+			string(APPEND COMPILE_COMMAND_JSON "${COMPILER_OPTIONS}")
+
+			if(MSVC)
+				string(APPEND COMPILE_COMMAND_JSON "${_el}")
+			else()
+				string(APPEND COMPILE_COMMAND_JSON " -c ${_el}")
+			endif()
+			string(APPEND COMPILE_COMMAND_JSON "\",\n\t},\n")
+		endforeach()
+		string(APPEND COMPILE_COMMAND_JSON "]")
+
+		file(GENERATE OUTPUT "$<TARGET_PROPERTY:${_target},BINARY_DIR>/$<CONFIG>/compile_commands.json" CONTENT "${COMPILE_COMMAND_JSON}")
+	endforeach()
+endfunction()
+
 function(clang_format)
 	cmake_parse_arguments(
 		PARSE_ARGV 0
-		_CLANG_FORMAT
+		_ARGS
 		"DEPENDENCY;GLOBAL"
 		"REGEX;VERSION"
 		"TARGETS"
@@ -13,7 +228,7 @@ function(clang_format)
 		"clang-format"
 		DOC "Path (or name) of the clang-format binary"
 		HINTS
-			${CLANG_PATH}
+			"${CLANG_PATH}"
 		PATHS
 			/bin
 			/sbin
@@ -30,44 +245,43 @@ function(clang_format)
 	endif()
 
 	# Validate Version
-	if (_CLANG_FORMAT_VERSION)
+	if (_ARGS_VERSION)
 		set(_VERSION_RESULT "")
 		set(_VERSION_OUTPUT "")
 		execute_process(
 			COMMAND "${CLANG_FORMAT_BIN}" --version
-			WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}
+			WORKING_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}"
 			RESULT_VARIABLE _VERSION_RESULT
 			OUTPUT_VARIABLE _VERSION_OUTPUT
-			OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_STRIP_TRAILING_WHITESPACE ERROR_QUIET
-			OUTPUT_QUIET ERROR_QUIET
+			OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_STRIP_TRAILING_WHITESPACE
+			ERROR_QUIET
 		)
 		if(NOT _VERSION_RESULT EQUAL 0)
 			message(WARNING "Clang: Could not discover version, disabling clang-format...")
 			return()
 		endif()
 		string(REGEX MATCH "([0-9]+\.[0-9]+\.[0-9]+)" _VERSION_MATCH ${_VERSION_OUTPUT})
-		if(NOT ${_VERSION_MATCH} VERSION_GREATER_EQUAL ${_CLANG_FORMAT_VERSION})
+		if(NOT ${_VERSION_MATCH} VERSION_GREATER_EQUAL ${_ARGS_VERSION})
 			message(WARNING "Clang: Old version discovered, disabling clang-format...")
 			return()
 		endif()
 	endif()
 
 	# Default Filter
-	if(NOT _CLANG_FORMAT_FILTER)
-		set(_CLANG_FORMAT_FILTER "\.(h|hpp|c|cpp)$")
+	if(NOT _ARGS_REGEX)
+		set(_ARGS_REGEX "\.(h|hpp|c|cpp)$")
 	endif()
 
 	# Go through each target
-	foreach(_target ${_CLANG_FORMAT_TARGETS})
-#		get_target_property(target_name ${_target} NAME)
-
+	foreach(_target ${_ARGS_TARGETS})
 		get_target_property(target_sources_rel ${_target} SOURCES)
 		set(target_sources "")
-		foreach(source_relative ${target_sources_rel})
-			get_filename_component(source_absolute ${source_relative} ABSOLUTE)
-			list(APPEND target_sources ${source_absolute})
+		foreach(_el ${target_sources_rel})
+			get_filename_component(_el "${_el}" ABSOLUTE)
+			file(TO_NATIVE_PATH "${_el}" _el)
+			list(APPEND target_sources "${_el}")
 		endforeach()
-		list(FILTER target_sources INCLUDE REGEX "${_CLANG_FORMAT_FILTER}")
+		list(FILTER target_sources INCLUDE REGEX "${_ARGS_REGEX}")
 		unset(target_sources_rel)
 		
 		get_target_property(target_source_dir_rel ${_target} SOURCE_DIR)
@@ -75,22 +289,16 @@ function(clang_format)
 		unset(target_source_dir_rel)
 
 		add_custom_target(${_target}_CLANG-FORMAT
-			COMMAND
-				${CLANG_FORMAT_BIN}
-				-style=file
-				-i
-				${target_sources}
-			COMMENT
-				"clang-format: Formatting ${_target}..."
-			WORKING_DIRECTORY
-				${target_source_dir_rel}
+			COMMAND "${CLANG_FORMAT_BIN}" -style=file -i ${target_sources}
+			COMMENT "clang-format: Formatting ${_target}..."
+			WORKING_DIRECTORY "${target_source_dir}"
 		)
 
-		if(_CLANG_FORMAT_DEPENDENCY)
+		if(_ARGS_DEPENDENCY)
 			add_dependencies(${_target} ${_target}_CLANG-FORMAT)
 		endif()
 
-		if(_CLANG_FORMAT_GLOBAL)
+		if(_ARGS_GLOBAL)
 			if(TARGET CLANG-FORMAT)
 				add_dependencies(CLANG-FORMAT ${_target}_CLANG-FORMAT)
 			else()
@@ -104,3 +312,120 @@ function(clang_format)
 		endif()
 	endforeach()
 endfunction()
+
+function(clang_tidy)
+	cmake_parse_arguments(
+		PARSE_ARGV 0
+		_ARGS
+		"DEPENDENCY;GLOBAL"
+		"REGEX;VERSION"
+		"TARGETS"
+	)
+
+	find_program(CLANG_TIDY_BIN
+		"clang-tidy"
+		DOC "Path (or name) of the clang-tidy binary"
+		HINTS
+			"${CLANG_PATH}"
+		PATHS
+			/bin
+			/sbin
+			/usr/bin
+			/usr/local/bin
+		PATH_SUFFIXES
+			bin
+			bin64
+			bin32
+	)
+	if(NOT CLANG_TIDY_BIN)
+		message(WARNING "Clang: Could not find clang-tidy at path '${CLANG_TIDY_BIN}', disabling clang-tidy...")
+		return()
+	endif()
+
+	# Validate Version
+	if (_ARGS_VERSION)
+		set(_VERSION_RESULT "")
+		set(_VERSION_OUTPUT "")
+		execute_process(
+			COMMAND "${CLANG_TIDY_BIN}" --version
+			WORKING_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}"
+			RESULT_VARIABLE _VERSION_RESULT
+			OUTPUT_VARIABLE _VERSION_OUTPUT
+			OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_STRIP_TRAILING_WHITESPACE
+			ERROR_QUIET
+		)
+		if(NOT _VERSION_RESULT EQUAL 0)
+			message(WARNING "Clang: Could not discover version, disabling clang-tidy...")
+			return()
+		endif()
+		string(REGEX MATCH "([0-9]+\.[0-9]+\.[0-9]+)" _VERSION_MATCH ${_VERSION_OUTPUT})
+		if(NOT ${_VERSION_MATCH} VERSION_GREATER_EQUAL ${_ARGS_VERSION})
+			message(WARNING "Clang: Old version discovered, disabling clang-tidy...")
+			return()
+		endif()
+	endif()
+
+	# Default Filter
+	if(NOT _ARGS_REGEX)
+		set(_ARGS_REGEX "\.(h|hpp|c|cpp)$")
+	endif()
+
+	# Go through each target
+	foreach(_target ${_ARGS_TARGETS})
+		# Source Directory
+		get_target_property(_els ${_target} SOURCE_DIR)
+		get_filename_component(target_source_dir ${_els} ABSOLUTE)
+		file(TO_NATIVE_PATH "${target_source_dir}" target_source_dir_nat)
+		unset(_els)
+
+		# Binary Directory
+		get_target_property(_els ${_target} BINARY_DIR)
+		get_filename_component(target_binary_dir ${_els} ABSOLUTE)
+		file(TO_NATIVE_PATH "${target_binary_dir}" target_binary_dir_nat)
+		unset(_els)
+
+		# Sources
+		get_target_property(_els ${_target} SOURCES)
+		set(target_sources "")
+		foreach(_el ${_els})
+			get_filename_component(_el ${_el} ABSOLUTE)
+			file(TO_NATIVE_PATH "${_el}" _el)
+			list(APPEND target_sources "${_el}")
+		endforeach()
+		list(FILTER target_sources INCLUDE REGEX "${_ARGS_REGEX}")
+		unset(_els)
+
+		add_custom_target(${_target}_CLANG-TIDY
+			COMMENT "clang-tiy: Tidying ${_target}..."
+			WORKING_DIRECTORY "${target_binary_dir}"
+			VERBATIM
+		)
+		foreach(_el ${target_sources})
+			add_custom_command(
+				TARGET ${_target}_CLANG-TIDY
+				POST_BUILD
+				COMMAND "${CLANG_TIDY_BIN}"
+				ARGS --quiet -p="$<TARGET_PROPERTY:${_target},BINARY_DIR>/$<CONFIG>" "${_el}"
+				WORKING_DIRECTORY "${target_binary_dir}"
+				COMMAND_EXPAND_LISTS
+			)
+		endforeach()
+
+		if(_ARGS_DEPENDENCY)
+			add_dependencies(${_target} ${_target}_CLANG-TIDY)
+		endif()
+
+		if(_ARGS_GLOBAL)
+			if(TARGET CLANG-TIDY)
+				add_dependencies(CLANG-TIDY ${_target}_CLANG-FORTIDYMAT)
+			else()
+				add_custom_target(CLANG-TIDY
+					DEPENDS
+						${_target}_CLANG-TIDY
+					COMMENT
+						"clang-tiy: Tidying..."
+				)
+			endif()
+		endif()
+	endforeach()
+endfunction()