On Wed, Jan 15, 2020 at 3:09 PM Alexey Bataev <a.bat...@outlook.com> wrote:
> And I disabled it only for device side, which is NVPTX, no? Can host side > target class report that the target is NVPTX? If you look at the patch, it > disable RTTI only if current triple is NVPTX. Can it be true for the host? > You are correct that the NVPTX as the triple is never used for the host compilation. However, I'm talking about host-side *code* as seen by compiler during device-side *compilation*. Keep in mind that both host and device compilations always see both sides of the source code. The host code seen by the compiler during device-side compilation should be allowed to use host features that are not available on GPU. When you RTTI got disabled for NVPTX, it affected *all* code seen by the compiler. When GPU-side compiler that targets NVPTX with RTTI disabled gets to parse the host function hf() (https://godbolt.org/z/Gzsrof) it sees typeid() and complains that RTTI is disabled, even though it will never produce any code for hf(). It should've allowed RTTI use in the host-only code. --Artem > ------------- > Best regards, > Alexey Bataev > > 15.01.2020 1:06 PM, Artem Belevich пишет: > > > > On Wed, Jan 15, 2020 at 2:52 PM Alexey Bataev <a.bat...@outlook.com> > wrote: > >> 1. The problem is that it does not produce errors, >> > ATM, it does produce errors when it's disabled. > >> it leads to the emission of some declaration that cannot be resolved by >> the linker. This what I was trying to avoid. >> > I'm OK with disabling it on device, but it should be done in a way to keep > RTTI in the host code working. > > E.g. this code should compile: https://godbolt.org/z/Gzsrof > It still has your original change, so clang compilation fails. It does not > with NVCC. > > 2. Yes, I did not disable it on the host side, just for the device side. I >> disabled it only for NVPTX target, which is the device. >> > It's fine to disable it for code generated for the target. However, the > front-end needs to be able to deal with the host-side code where it is OK > to use RTTI. > > --Artem > > > > >> ------------- >> Best regards, >> Alexey Bataev >> >> 15.01.2020 12:49 PM, Artem Belevich пишет: >> >> Thank you. >> >> In general, RTTI should probably be treated similar to how we deal with >> inline assembly and ignore errors if they are in the code that we're not >> going to codegen during this side of compilation. E.g. during host-side >> compilation we don't complain about GPU-side registers in inline assembly >> that x86 target is not aware of. >> >> Disabling RTTI altogether on device side makes it impossible to use in >> any host-side CUDA because RTTI code will be seen by the device-side >> compiler, which will promptly fail, which is exactly what happened in this >> case -- host-side template that relied on RTTI failed during device-side >> compilation: >> >> >> https://github.com/protocolbuffers/protobuf/blob/master/src/google/protobuf/arena.h#L536 >> google/protobuf/arena.h:536:15: error: use of typeid requires -frtti >> AllocHook(RTTI_TYPE_ID(T), n); >> ... >> 2 errors generated when compiling for sm_60. >> >> --Artem >> >> On Wed, Jan 15, 2020 at 2:36 PM Alexey Bataev <a.bat...@outlook.com> >> wrote: >> >>> Sure, will revert it ASAP. >>> >>> ------------- >>> Best regards, >>> Alexey Bataev >>> >>> 15.01.2020 12:26 PM, Artem Belevich пишет: >>> >>> Alexey, >>> >>> This breaks compilation of our cuda code which happens to transitively >>> include protobuf headers. >>> Can you, please, revert it for now until we figure out how RTTI should >>> be handled? >>> >>> --Artem >>> >>> On Tue, Jan 14, 2020 at 3:15 PM Alexey Bataev via cfe-commits < >>> cfe-commits@lists.llvm.org> wrote: >>> >>>> >>>> Author: Alexey Bataev >>>> Date: 2020-01-14T18:12:06-05:00 >>>> New Revision: 23058f9dd4d7e18239fd63b6da52549514b45fda >>>> >>>> URL: >>>> https://github.com/llvm/llvm-project/commit/23058f9dd4d7e18239fd63b6da52549514b45fda >>>> DIFF: >>>> https://github.com/llvm/llvm-project/commit/23058f9dd4d7e18239fd63b6da52549514b45fda.diff >>>> >>>> LOG: [OPENMP]Do not use RTTI by default for NVPTX devices. >>>> >>>> NVPTX does not support RTTI, so disable it by default. >>>> >>>> Added: >>>> clang/test/Driver/openmp-offload-gpu.cpp >>>> >>>> Modified: >>>> clang/lib/Driver/ToolChain.cpp >>>> >>>> Removed: >>>> >>>> >>>> >>>> >>>> ################################################################################ >>>> diff --git a/clang/lib/Driver/ToolChain.cpp >>>> b/clang/lib/Driver/ToolChain.cpp >>>> index cab97b1a601a..3ebbd30195b3 100644 >>>> --- a/clang/lib/Driver/ToolChain.cpp >>>> +++ b/clang/lib/Driver/ToolChain.cpp >>>> @@ -68,7 +68,8 @@ static ToolChain::RTTIMode CalculateRTTIMode(const >>>> ArgList &Args, >>>> } >>>> >>>> // -frtti is default, except for the PS4 CPU. >>>> - return (Triple.isPS4CPU()) ? ToolChain::RM_Disabled : >>>> ToolChain::RM_Enabled; >>>> + return (Triple.isPS4CPU() || Triple.isNVPTX()) ? >>>> ToolChain::RM_Disabled >>>> + : >>>> ToolChain::RM_Enabled; >>>> } >>>> >>>> ToolChain::ToolChain(const Driver &D, const llvm::Triple &T, >>>> >>>> diff --git a/clang/test/Driver/openmp-offload-gpu.cpp >>>> b/clang/test/Driver/openmp-offload-gpu.cpp >>>> new file mode 100644 >>>> index 000000000000..9da7308506ae >>>> --- /dev/null >>>> +++ b/clang/test/Driver/openmp-offload-gpu.cpp >>>> @@ -0,0 +1,20 @@ >>>> +/// >>>> +/// Perform several driver tests for OpenMP offloading >>>> +/// >>>> + >>>> +// REQUIRES: clang-driver >>>> +// REQUIRES: x86-registered-target >>>> +// REQUIRES: powerpc-registered-target >>>> +// REQUIRES: nvptx-registered-target >>>> + >>>> +/// >>>> ########################################################################### >>>> + >>>> +/// PTXAS is passed -c flag by default when offloading to an NVIDIA >>>> device using OpenMP >>>> +/// Check that the flag is passed when -fopenmp-relocatable-target is >>>> used. >>>> +// RUN: %clangxx -### -fopenmp=libomp >>>> -fopenmp-targets=nvptx64-nvidia-cuda \ >>>> +// RUN: -save-temps -no-canonical-prefixes %s -x c++ -c 2>&1 \ >>>> +// RUN: | FileCheck -check-prefix=CHK-RTTI %s >>>> + >>>> +// CHK-RTTI: clang{{.*}}" "-triple" "nvptx64-nvidia-cuda" >>>> +// CHK-RTTI-SAME: "-fno-rtti" >>>> + >>>> >>>> >>>> >>>> _______________________________________________ >>>> cfe-commits mailing list >>>> cfe-commits@lists.llvm.org >>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >>>> >>> >>> >>> -- >>> --Artem Belevich >>> >>> >> >> -- >> --Artem Belevich >> >> > > -- > --Artem Belevich > > -- --Artem Belevich
_______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
