peixin added inline comments.
================ Comment at: flang/runtime/environment.cpp:77 +#else + envp = environ; +#endif ---------------- What is `environ` used for? Should we try to keep as less extern variable as possible in runtime for security. ================ Comment at: flang/test/Driver/emit-mlir.f90:16 ! CHECK-NEXT: } +! CHECK-NEXT: fir.global @_QQEnvironmentDefaults constant : !fir.ref<tuple<i[[int_size:.*]], !fir.ref<!fir.array<0xtuple<!fir.ref<i8>, !fir.ref<i8>>>>>> { +! CHECK-NEXT: %[[VAL_0:.*]] = fir.zero_bits !fir.ref<tuple<i[[int_size]], !fir.ref<!fir.array<0xtuple<!fir.ref<i8>, !fir.ref<i8>>>>>> ---------------- jpenix-quic wrote: > peixin wrote: > > Is it possible not to generated this global variable if `fconvert=` is not > > specified? > I'm not entirely sure--the issue I was running into was how to handle this in > Fortran_main.c in a way which worked for all of GCC/Clang/Visual Studio (and > maybe others?). I was originally thinking of doing this by using a weak > definition of _QQEnvironmentDefaults set to nullptr so fconvert, etc. could > override this definition without explicitly generating the fallback case. For > GCC/clang, I think I could use __attribute__((weak)), but I wasn't sure how > to handle this if someone tried to build with Visual Studio (or maybe another > toolchain). I saw a few workarounds (ex: > https://devblogs.microsoft.com/oldnewthing/20200731-00/?p=104024) but I shied > away from this since it seems to be an undocumented feature (and presumably > only helps with Visual Studio). > > Do you know of a better or more general way I could do this? (Or, is there > non-weak symbol approach that might be better that I'm missing?) How about generate one runtime function with the argument of `EnvironmentDefaultList`? This will avoid this and using one extern variable? If users use one variable with bind C name `_QQEnvironmentDefaults` in fortran or one variable with name `_QQEnvironmentDefaults` in C, it is risky. Would using the runtime function and static variable with the type `EnvironmentDefaultList` in runtime be safer? CHANGES SINCE LAST ACTION https://reviews.llvm.org/D130513/new/ https://reviews.llvm.org/D130513 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits