delcypher added inline comments.
================ Comment at: clang/include/clang/Driver/Options.td:1485 +def sanitize_address_destructor_kind_EQ : Joined<["-"], "fsanitize-address-destructor-kind=">, + MetaVarName<"<kind>">, + Flags<[CC1Option]>, ---------------- vitalybuka wrote: > delcypher wrote: > > delcypher wrote: > > > vitalybuka wrote: > > > > What is the difference between them and why it's need to be configured > > > > from outside? > > > Good questions. > > > > > > > What is the difference between them > > > > > > I'll add some documentation to explain this. But the two different modes > > > are introduced by https://reviews.llvm.org/D96571. Basically the default > > > ("global") emits ASan module destructor calls via `llvm.global_dtors` > > > which was the previous behaviour. The other mode "none" simply causes no > > > ASan module destructors to be emitted. I plan to introduce another mode > > > in a future patch. > > > > > > > why it's need to be configured from outside? > > > > > > At the bare minimum this option needs to be controllable by the driver so > > > that we can do the next patch (https://reviews.llvm.org/D96573) where > > > based on target details and other flags we set the ASan destructor kind. > > > This means that the frontend needs to be able to consume to option too. > > > > > > It is technically not necessary for this new option to be a driver > > > option. However, I made it a driver option too to match the existing ASan > > > clang frontend options which are also driver options (e.g. > > > `-fsanitize-address-use-odr-indicator`). > > @vitalybuka To expand on my answer a little more. > > `-fsanitize-address-destructor-kind=` is needed because we need to able to > > control how ASan's module are emitted and unfortunately the information > > required to make the decision on which kind to emit **is not available at > > the level of LLVM IR**. The information we need to be able to make the > > decision is only available in the Clang driver. This is why this patch > > wires everything up so that the driver can change how ASan module > > destructors are emitted. > > @vitalybuka To expand on my answer a little more. > > `-fsanitize-address-destructor-kind=` is needed because we need to able to > > control how ASan's module are emitted and unfortunately the information > > required to make the decision on which kind to emit **is not available at > > the level of LLVM IR**. The information we need to be able to make the > > decision is only available in the Clang driver. This is why this patch > > wires everything up so that the driver can change how ASan module > > destructors are emitted. > > I didn't check all patches yet, but we have -fsanitize=kernel-address and I > noticed that your patches mentioned kernel. Could be possible just use > -fsanitize=kernel-address and let ASan decide how to handle dtors for this > platform? @vitalybuka Unfortunately using `-fsanitize=kernel-address` isn't a viable option. In a future patch I'll be adding another destructor kind where the decision to use it is **also unfortunately not known at the LLVM IR level** and is instead only known by Clang driver. If you really don't want `-fsanitize-address-destructor-kind=` exposed as driver option (i.e. exposed to our users) we could make it a frontend (cc1) only option. However, that doesn't really seem to match the existing sanitizer frontend options which all seem to be driver options as well. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D96572/new/ https://reviews.llvm.org/D96572 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
