https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66487
--- Comment #18 from Martin Liška <marxin at gcc dot gnu.org> --- (In reply to Martin Liška from comment #16) > (In reply to Jakub Jelinek from comment #14) > > (In reply to Jason Merrill from comment #4) > > > Actually, I guess checking for this is more of a fit for an uninitialized > > > read detector such as MemorySanitizer or Valgrind memcheck. > > > > Well, AddressSanitizer should be able to do that too with some extra work, > > what we need is know not just when the lifetime of a variable ends, but also > > when it starts, and instrument those two, plus disable reusing variable > > stack slots when instrumenting. In the function prologue we'd then mark the > > variables as unavailable, not just their padding, and then when they get > > into scope (that is the first clobber these days), we'd mark them enabled > > and when they get out of scope (second clobber) mark them unavailable again. > > GCC7 material. > > Hi Jakub. > > I've already made a prototype implementation that can do that: > https://groups.google.com/forum/#!topic/address-sanitizer/WYdZIo6lnyA > > It's quite limited to just heap allocation and memory sizes different from > multiples of 8B are not correctly handled, but I'm rewriting the patch to > prepare it as GCC 7 material. > > Moreover, Honza suggested that we can use the scaffolding to do a run-time > memory aliasing sanitizer that will verify that a memory is accessed just > from compatible alias sets. Also GCC 7 material. > > Martin Another update: looks the desired feature is already implemented by MemorySanitizer: https://github.com/google/sanitizers/wiki/MemorySanitizer Thus, writing just code emission on side of the GCC compiler should enable the functionality. I'll take a look. Martin
