如何确定何时使用-fsanitize = memory？

Question

当内存清洁剂正在使用时，我想清除FD_ZERO和FD_SET上的误报。清除它有点容易：

#include <sanitizer/msan_interface.h> 
... 

__msan_unpoison(&readfds, sizeof(readfds)); 
__msan_unpoison(&writefds, sizeof(writefds)); 

但是，我不知道如何检测何时使用内存消毒剂。即，在命令行上指定-fsanitize=memory时检测。预处理似乎并不被帮助：

$ clang -dM -E -fsanitize=memory - </dev/null | egrep -i 'memory|sanitize|msan' 
$ 

我怎么能确定何时-fsanitize=memory在使用？

Answer 1

根据Konstantin Serebryany的Memory Sanitizer mailing list，没有预处理宏。应该使用__has_feature(memory_sanitizer)：

#if defined(__has_feature) 
# if __has_feature(memory_sanitizer) 
# define MEMORY_SANITIZER 1 
# endif 
#endif 
... 

#ifdef MEMORY_SANITIZER 
# include <sanitizer/msan_interface.h> 
#endif 
... 

#ifdef MEMORY_SANITIZER 
__msan_unpoison(&readfds, sizeof(readfds)); 
__msan_unpoison(&writefds, sizeof(writefds)); 
#endif 
...