On Wed, Nov 2, 2016 at 2:06 PM, Jakub Jelinek <ja...@redhat.com> wrote: > On Wed, Nov 02, 2016 at 01:59:00PM +0100, Richard Biener wrote: >> > Yeah, that is what I meant. The issue is how to report uses of such >> > SSA_NAME when there is no memory. So, either we'd need a special runtime >> > library entrypoint that would report uses after scope even when there is no >> > underlying memory, or we'd need to force it at asan pass time into memory >> > again. >> >> Well, there can't be any uses outside the scope -- there are no (memory) uses >> left if we rewrite the thing into SSA. That is, the address can no >> longer "escape". >> >> Of course there could have been invalid uses before the rewrite into SSA. >> But >> those can be diagnosed either immediately before or after re-writing into SSA >> at compile-time (may be in dead code regions of course). > > Sure, we can warn on those at compile time, but we really should arrange to > error on those at runtime if they are ever executed, the UB happens only at > runtime, so in dead code isn't fatal.
Then we can replace those uses with a call into the asan runtime diagnosing the issue instead? Richard. > Jakub
