build: disable fuzztest when building with TSAN

fuzztest's coverage instrumentation is incompatible with Thread
Sanitizer. Add px4_setup_gtest_without_fuzztest() macro to
cmake/px4_add_gtest.cmake that fetches GTest standalone and stubs out
fuzztest cmake functions. Guard all fuzztest-specific code on
TARGET fuzztest::fuzztest so it compiles cleanly without fuzztest.

cmake/px4_add_gtest.cmake

@@ -31,6 +31,30 @@
 #
 ############################################################################
 
+#=============================================================================
+#
+#	px4_setup_gtest_without_fuzztest
+#
+#	Fetches GTest standalone and stubs out fuzztest cmake functions.
+#	Used when fuzztest is not available (e.g. TSAN builds where fuzztest's
+#	coverage instrumentation is incompatible).
+#
+macro(px4_setup_gtest_without_fuzztest)
+	include(FetchContent)
+	FetchContent_Declare(
+		googletest
+		GIT_REPOSITORY https://github.com/google/googletest.git
+		GIT_TAG v1.16.0
+	)
+	FetchContent_MakeAvailable(googletest)
+
+	function(link_fuzztest name)
+		target_link_libraries(${name} PRIVATE gtest gtest_main)
+	endfunction()
+	macro(fuzztest_setup_fuzzing_flags)
+	endmacro()
+endmacro()
+
 #=============================================================================
 #
 #	px4_add_unit_gtest
@@ -98,23 +122,28 @@ function(px4_add_functional_gtest)
 		add_executable(${TESTNAME} EXCLUDE_FROM_ALL ${SRC} ${EXTRA_SRCS})
 
 		# link the libary to test and gtest
-		target_link_libraries(${TESTNAME} PRIVATE ${LINKLIBS} gtest_functional_main
+		set(_FUNCTIONAL_GTEST_LIBS ${LINKLIBS} gtest_functional_main
-		                                              px4_layer
+		                           px4_layer
-		                                              px4_platform
+		                           px4_platform
-		                                              uORB
+		                           uORB
-		                                              systemlib
+		                           systemlib
-		                                              cdev
+		                           cdev
-		                                              px4_work_queue
+		                           px4_work_queue
-		                                              px4_daemon
+		                           px4_daemon
-		                                              work_queue
+		                           work_queue
-		                                              parameters
+		                           parameters
-		                                              events
+		                           events
-		                                              perf
+		                           perf
-		                                              tinybson
+		                           tinybson
-		                                              uorb_msgs
+		                           uorb_msgs)
-		                                              fuzztest::fuzztest # Do not use link_fuzztest() here because that
+		if(TARGET fuzztest::fuzztest)
-				                                      # also links to fuzztest_gtest_main
+			list(APPEND _FUNCTIONAL_GTEST_LIBS fuzztest::fuzztest) # Do not use link_fuzztest() here because that
-		                                              test_stubs)  # put test_stubs last
+			                                                       # also links to fuzztest_gtest_main
+		else()
+			list(APPEND _FUNCTIONAL_GTEST_LIBS gtest)
+		endif()
+		list(APPEND _FUNCTIONAL_GTEST_LIBS test_stubs) # put test_stubs last
+		target_link_libraries(${TESTNAME} PRIVATE ${_FUNCTIONAL_GTEST_LIBS})
 
 		target_compile_definitions(${TESTNAME} PRIVATE MODULE_NAME="${TESTNAME}")
 

platforms/posix/CMakeLists.txt

@@ -28,7 +28,7 @@ add_executable(px4
 	apps.cpp
 	)
 
-if (BUILD_TESTING)
+if (BUILD_TESTING AND TARGET fuzztest::fuzztest)
 	# Build mavlink fuzz tests. These run other modules and thus cannot be a functional/unit test
 	add_executable(mavlink_fuzz_tests EXCLUDE_FROM_ALL
 		src/px4/common/mavlink_fuzz_tests.cpp

platforms/posix/src/px4/common/gtest_runner/CMakeLists.txt

@@ -36,4 +36,9 @@ set(SRCS
    )
 
 px4_add_library(gtest_functional_main ${SRCS})
-target_link_libraries(gtest_functional_main PUBLIC gtest fuzztest::init_fuzztest)
+if(TARGET fuzztest::init_fuzztest)
+	target_link_libraries(gtest_functional_main PUBLIC gtest fuzztest::init_fuzztest)
+	target_compile_definitions(gtest_functional_main PRIVATE HAVE_FUZZTEST)
+else()
+	target_link_libraries(gtest_functional_main PUBLIC gtest)
+endif()

platforms/posix/src/px4/common/gtest_runner/gtest_functional_main.cpp

@@ -32,7 +32,9 @@
  ****************************************************************************/
 
 #include <gtest/gtest.h>
+#ifdef HAVE_FUZZTEST
 #include <fuzztest/init_fuzztest.h>
+#endif
 
 #include <uORB/Subscription.hpp>
 
@@ -42,8 +44,10 @@ int main(int argc, char **argv)
 {
 	testing::InitGoogleTest(&argc, argv);
 
+#ifdef HAVE_FUZZTEST
 	fuzztest::ParseAbslFlags(argc, argv);
 	fuzztest::InitFuzzTest(&argc, &argv);
+#endif
 
 	uORB::Manager::initialize();
 	param_init();

src/drivers/gnss/septentrio/CMakeLists.txt

@@ -49,14 +49,16 @@ px4_add_module(
 		module.yaml
 	)
 
-px4_add_functional_gtest(SRC septentrio_fuzz_tests.cpp
+if(TARGET fuzztest::fuzztest)
-	LINKLIBS
+	px4_add_functional_gtest(SRC septentrio_fuzz_tests.cpp
-		driver__septentrio
+		LINKLIBS
-	COMPILE_FLAGS
+			driver__septentrio
-		# There warnings come from within fuzztest
+		COMPILE_FLAGS
-		-Wno-float-equal
+			# There warnings come from within fuzztest
-		-Wno-sign-compare
+			-Wno-float-equal
-		-Wno-shadow
+			-Wno-sign-compare
-		-Wno-extra
+			-Wno-shadow
-		-Wno-non-template-friend
+			-Wno-extra
-)
+			-Wno-non-template-friend
+	)
+endif()

test/CMakeLists.txt

@@ -1,8 +1,12 @@
-px4_add_git_submodule(TARGET git_fuzztest PATH "fuzztest")
+if(CMAKE_BUILD_TYPE STREQUAL "ThreadSanitizer")
-
+	message(STATUS "TSAN build: skipping fuzztest, fetching GTest only")
-message(STATUS "Adding fuzztest")
+	px4_setup_gtest_without_fuzztest()
-# This will also add GTest
+else()
-add_subdirectory(fuzztest EXCLUDE_FROM_ALL)
+	px4_add_git_submodule(TARGET git_fuzztest PATH "fuzztest")
+	message(STATUS "Adding fuzztest")
+	# This will also add GTest
+	add_subdirectory(fuzztest EXCLUDE_FROM_ALL)
+endif()
 
 # Ensure there's no -R without any filter expression since that trips newer ctest versions
 if(TESTFILTER)