[Openmp-dev] Mapping of non-trivial type support

[Itaru Kitayama via Openmp-dev]

$ cat test.cpp
int main() {
int a;
#pragma omp declare target to (a)

}
$ clang++ -fopenmp -fopenmp-targets=nvptx64 test.cpp
test.cpp:3:21: error: unexpected OpenMP directive '#pragma omp declare
target'
#pragma omp declare target to (a)
                    ^
1 error generated.

Tested with the latest trunk Clang on POWER8.

On Fri, Aug 9, 2019 at 9:34 AM Alexey Bataev <a.bataev at hotmail.com> wrote:

> A a;
> #pragma omp declare target to(a)
>
> Best regards,
> Alexey Bataev
>
> 8 авг. 2019 г., в 20:31, Itaru Kitayama <itaru.kitayama at gmail.com>
> написал(а):
>
> Ravi,
> Do you have a simple C++ code that does show how it is done? As I am still
> inserting a line
>
> A a;
>
> #pragma omp target data map(alloc: a)
>
> ?
>
> On Fri, Aug 9, 2019 at 8:28 AM Narayanaswamy, Ravi <
> ravi.narayanaswamy at intel.com> wrote:
>
>> Correct.
>> We are still working on supporting function pointers which should include
>> support for virtual function.
>>
>> You can mark the class and object with declare target and use the object
>> to invoke virtual function.
>> Currently you cannot pass an object through the map clause and use
>> virtual function with that object.
>>
>> -----Original Message-----
>> From: Doerfert, Johannes [mailto:jdoerfert at anl.gov]
>> Sent: Thursday, August 8, 2019 4:24 PM
>> To: Itaru Kitayama <itaru.kitayama at gmail.com>
>> Cc: Alexey Bataev <a.bataev at hotmail.com>; openmp-dev at lists.llvm.org;
>> Narayanaswamy, Ravi <ravi.narayanaswamy at intel.com>
>> Subject: Re: [Openmp-dev] Mapping of non-trivial type support
>>
>> You mean, calling a virtual function of a mapped object?
>> That is, as far as I know, not OpenMP 5.0. It might make it in 5.1 though.
>> (Allocating the object on the device and then calling a virtual function
>> should be fine though.)
>>
>> @Ravi Is this correct?
>>
>> ________________________________________
>> From: Itaru Kitayama <itaru.kitayama at gmail.com>
>> Sent: Thursday, August 8, 2019 18:15
>> To: Doerfert, Johannes
>> Cc: Alexey Bataev; openmp-dev at lists.llvm.org
>> Subject: Re: [Openmp-dev] Mapping of non-trivial type support
>>
>> In which issue the virtual function offloading feature support being
>> worked on? I am not certain still after going over the OpenMP 5.0 features
>> list.
>>
>>
>> On Fri, Aug 9, 2019 at 2:32 AM Doerfert, Johannes <jdoerfert at anl.gov
>> <mailto:jdoerfert at anl.gov>> wrote:
>> Itaru, a webpage with implementation status details is in the works,
>>   https://reviews.llvm.org/D64375
>> but it seems hard to agree on an initial version.
>>
>> On 08/05, Itaru Kitayama via Openmp-dev wrote:
>> > Alexey et al.,
>> > What's the plan for OpenMP 5.0 API adoption in Clang? Would you point
>> > me to a link to an appropriate web page?
>> > Is there an OpenMP 5.0 API work-in-progress branch which I can give it
>> > a try?
>> >
>> > On Sun, Aug 4, 2019 at 8:57 PM Alexey Bataev <a.bataev at hotmail.com
>> <mailto:a.bataev at hotmail.com>> wrote:
>> >
>> > > clang works in accordance with the standard. Standard says that
>> > > mapping is performed as bitwise copy of the objects. You can perform
>> > > the bitwise copy safely only for the trivial types.
>> > > You cannot simply map a vector. You need to convert it to C/C++
>> > > array at first.
>> > > OpenMP 5.0 introduced user-defined mappers to solve the problem of
>> > > non-trivial types mapping, which are not supported by clang yet.
>> > > We're working on this feature.
>> > >
>> > > Best regards,
>> > > Alexey Bataev
>> > >
>> > > > 4 авг. 2019 г., в 1:16, Itaru Kitayama via Openmp-dev <
>> > > openmp-dev at lists.llvm.org<mailto:openmp-dev at lists.llvm.org>>
>> написал(а):
>> > > >
>> > > > Hi,
>> > > > This simple code:
>> > > >
>> > > > int main() {
>> > > >
>> > > > std::vector<int> v(100, 0);
>> > > > #pragma omp target teams distribute parallel for map(tofrom: v)
>> > > >    for (int i=0;i<100;i++) {
>> > > >         v[i] =i;
>> > > >    }
>> > > > };
>> > > >
>> > > > causes Clang to warn a message like:
>> > > >
>> > > > vectormap.cpp:31:62: warning: Non-trivial type 'std::vector<int>'
>> > > > is
>> > > mapped, only trivial types are guaranteed to be mapped correctly
>> > > [-Wopenmp-target]
>> > > > #pragma omp target teams distribute parallel for map(tofrom: v)
>> > > >
>> > > >                                    ^
>> > > > 1 warning generated.
>> > > >
>> > > > ... and encounters an issue at run time. How much non-trivial
>> > > > types are supported in trunk Clang?
>> > > > _______________________________________________
>> > > > Openmp-dev mailing list
>> > > > Openmp-dev at lists.llvm.org<mailto:Openmp-dev at lists.llvm.org>
>> > > > https://lists.llvm.org/cgi-bin/mailman/listinfo/openmp-dev
>> > >
>>
>> > _______________________________________________
>> > Openmp-dev mailing list
>> > Openmp-dev at lists.llvm.org<mailto:Openmp-dev at lists.llvm.org>
>> > https://lists.llvm.org/cgi-bin/mailman/listinfo/openmp-dev
>>
>>
>> --
>>
>> Johannes Doerfert
>> Researcher
>>
>> Argonne National Laboratory
>> Lemont, IL 60439, USA
>>
>> jdoerfert at anl.gov<mailto:jdoerfert at anl.gov>
>>
>
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