On Fri, Aug 16, 2019 at 09:52:17PM -0700, Paul E. McKenney wrote: > On Fri, Aug 16, 2019 at 03:57:43PM -0700, Linus Torvalds wrote: > > [ . . . ] > > > We add READ_ONCE and WRITE_ONCE annotations when they make sense. Not > > because of some theoretical "compiler is free to do garbage" > > arguments. If such garbage happens, we need to fix the compiler, the > > same way we already do with > > > > -fno-strict-aliasing > > Yeah, the compete-with-FORTRAN stuff. :-/ > > There is some work going on in the C committee on this, where the > theorists would like to restrict strict-alias based optimizations to > enable better analysis tooling. And no, although the theorists are > pushing in the direction we would like them to, as far as I can see > they are not pushing as far as we would like. But it might be that > -fno-strict-aliasing needs some upgrades as well. I expect to learn > more at the next meeting in a few months. > > http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2364.pdf > http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2363.pdf > http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2362.pdf
We really should get the compiler folks to give us a -fno-pointer-provenance. Waiting on the standards committee to get their act together seems unlikely, esp. given that some people actually seem to _want_ this nonsense :/
