From b3d77c8ea035e1fb42131eec5c274ca0adce5627 Mon Sep 17 00:00:00 2001
From: makise-homura <makise-homura@users.noreply.github.com>
Date: Fri, 28 Apr 2017 22:37:19 +0300
Subject: [PATCH] Implemented checking for UBSAN compiler option for Debug (and
 RelWithDebInfo) build types.

---
 src/CMakeLists.txt | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 310668a3..80d0b9af 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -135,8 +135,19 @@ message(STATUS "Build configuration: ${CMAKE_BUILD_TYPE}")
 set(DEBUG_FLAGS "-ggdb -fno-omit-frame-pointer")
 set(RELEASE_FLAGS "-DNDEBUG")
 
-if(DEBUG_USE_UBSAN)
-	set(DEBUG_FLAGS "${DEBUG_FLAGS} -fsanitize=undefined")
+if("${CMAKE_BUILD_TYPE}" STREQUAL "Debug" OR "${CMAKE_BUILD_TYPE}" STREQUAL "RelWithDebInfo")
+	# "Debug build" is a build where ${DEBUG_FLAGS} are used.
+	set(DEBUG_BUILD TRUE)
+endif()
+
+if(DEBUG_USE_UBSAN AND DEFINED DEBUG_BUILD)
+	include(CheckCCompilerFlag)
+	CHECK_C_COMPILER_FLAG("-fsanitize=undefined" COMPILER_SUPPORTS_UBSAN)
+	if(COMPILER_SUPPORTS_UBSAN)
+		set(DEBUG_FLAGS "${DEBUG_FLAGS} -fsanitize=undefined")
+	else()
+		message(STATUS "  DEBUG_USE_UBSAN not supported by compiler, turned off.")
+	endif()
 endif()
 
 if(DEBUG_USE_ASAN)