yaxunl added a comment. In D95901#2539663 <https://reviews.llvm.org/D95901#2539663>, @tra wrote:
>> For -fgpu-rdc, shadow variables should not be internalized, otherwise they >> cannot be accessed by other TUs. >> This is necessary because the shadow variable of external device variables >> are always emitted as undefined symbols, which need to resolve to a global >> symbols. > > Does it mean that we always internalize shadows *now*, before this patch? > That would indeed be wrong. Shadow's visibility should be the same as that of > a variable without a `__device__`. Yes before this patch we always internalize shadow vars. > Next question is whether the behavior should be different for `-fgpu-rdc` vs > non-RDC. I think shadows should behave the same regardless of RDC mode and > make things work closer to what users would expect from regular C++ code. We > already have mechanisms to uniquify the variables, if necessary, so we don't > need to use visibility to avoid cross-TU linking conflicts. For -fno-gpu-rdc, two TU's can have global device variables with the same name, therefore the shadow variables need to be internalized, which is fine since -fno-gpu-rdc is not supposed to access device variables across TU's. So far users did not report issues about shadow var linkage for -fno-gpu-rdc (they reported shadow var linkage issues for -fgpu-rdc only). Let the shadow vars keep original linkage and use CUID to make them unique would be unnecessary and clutter the IR. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D95901/new/ https://reviews.llvm.org/D95901 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
