Hello, On Fri, Apr 08 2022, Pedro Alves wrote: > Hi! > > I noticed the discussions about making cp-demangle use malloc/free instead of > recursion, > and I wonder about signal handlers, and I don't see that mentioned in > https://gcc.gnu.org/wiki/SummerOfCode's description of the project. > > See my question to Ian a few years back, here, and his answer: > > https://gcc.gnu.org/legacy-ml/gcc-patches/2018-12/msg00696.html
thanks for the pointer, I also stumbled across these only recently. Indeed it seems it may be necessary to also have a variant that would have to rely on alloca in the main driving loop to allocate the explicit stack... which will make the code a bit ugly but hopefully not that much. But this can be handled incrementally once we can get the normal mode of operation working. Thanks again, Martin > > ~~~ > Ian says: > > Pedro says: > > Ian earlier mentioned that we've wanted to avoid malloc because some > > programs call the demangler from a signal handler, but it seems like > > we already do, these functions already aren't safe to use from > > signal handlers as is. Where does the "we can't use malloc" idea > > come from? Is there some entry point that avoids > > the malloc/realloc/free calls? > > cplus_demangle_v3_callback and cplus_demangle_print_callback. > ~~~ > > Grepping the gcc tree, I see that libsanitizer uses those entry points. > > Is async-signal safety no longer a consideration/concern? Or will those > entry points > continue to work without calling malloc/free somehow?
