Concurrent GC's isn't a mess I've dealt with (majority single-threaded languages), moving should be ok if all heap accesses are in single statements through the

Concurrent GC's isn't a mess I've dealt with (majority single-threaded languages), moving should be ok if all heap accesses are in single statements through the shadow stack and a pointer to the shadow-stack is always passed on to called functions (Thus the compiler shouldn't be allowed to retain anything, I could be wrong on some slight C standard detail here though).