如何确定何时使用-fsanitize =内存？

Question

我想在使用内存消毒剂时清除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，我不知道如何检测内存消毒剂何时使用。也就是说，检测命令行上何时指定-fsanitize=memory。预处理器似乎没有帮助：

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

如何确定何时使用-fsanitize=memory？

Answer 1

根据Memory Sanitizer mailing list的Konstantin Serebryany的说法，没有预处理器宏。应使用__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
...