[Openmp-dev] issue with opennp and clang

Tue Nov 25 14:27:19 PST 2014

Jeremey,

Could you let me know if in the LLVM-openMP project we have the same opt
<flags> as the default llvm-opt <flags> ?

as I am running these procedures:

1- clang(Openmp) -S -emit-llvm -fopenmp llvm_openmp.c

2- opt(Openmp) <some flags> -S -o hello_opt.ll hello.ll

3- clang(Openmp) hello_opt.ll -lm

 I am getting :

[ashouri at savina openmp_power]$ clang -v llvm_openmp.ll -lm

clang version 3.5.0 (https://github.com/clang-omp/clang
05ab95f7cb2779bbf20341ae6ed293106de5afda) (https://github.com/clang-omp/llvm
e45b045553e027cbe400cbb8ac8c264abbbfaf83)

Target: x86_64-unknown-linux-gnu

Thread model: posix

Found candidate GCC installation: /usr/lib/gcc/i686-redhat-linux/4.4.4

Found candidate GCC installation: /usr/lib/gcc/i686-redhat-linux/4.4.7

Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/4.4.4

Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/4.4.7

Selected GCC installation: /usr/lib/gcc/x86_64-redhat-linux/4.4.7

Candidate multilib: .;@m64

Candidate multilib: 32;@m32

Selected multilib: .;@m64

 "~/llvm/build/Debug+Asserts/bin/clang" -cc1 -triple
x86_64-unknown-linux-gnu -emit-obj -mrelax-all -disable-free
-main-file-name llvm_openmp.ll -mrelocation-model static -mdisable-fp-elim
-fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables
-target-cpu x86-64 -target-linker-version 2.20.51.0.2 -v -dwarf-column-info
-resource-dir ~llvm/build/Debug+Asserts/bin/../lib/clang/3.5.0
-fdebug-compilation-dir /usa/ashouri/phase_ordering/openmp_power
-ferror-limit 19 -fmessage-length 204 -mstackrealign -fobjc-runtime=gcc
-fdiagnostics-show-option -fcolor-diagnostics -o /tmp/llvm_openmp-3af5c7.o
-x ir llvm_openmp.ll

clang -cc1 version 3.5.0 based upon LLVM 3.5.0 default target
x86_64-unknown-linux-gnu

 "/usr/bin/ld" --eh-frame-hdr -m elf_x86_64 -dynamic-linker
/lib64/ld-linux-x86-64.so.2 -o a.out
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/crt1.o
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/crti.o
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/crtbegin.o
-L/usr/lib/gcc/x86_64-redhat-linux/4.4.7
-L/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64 -L/lib/../lib64
-L/usr/lib/../lib64 -L/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../..
-L/~/llvm/build/Debug+Asserts/bin/../lib -L/lib -L/usr/lib
/tmp/llvm_openmp-3af5c7.o -lm -L. -L/~/openmp/runtime/exports/lin_32e/lib
-L~/openmp/runtime/exports/lin_32e/lib -lgcc --as-needed -lgcc_s
--no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/crtend.o
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/crtn.o

/tmp/llvm_openmp-3af5c7.o: In function `main':

llvm_openmp.ll:(.text+0x75): undefined reference to `__kmpc_fork_call'

/tmp/llvm_openmp-3af5c7.o: In function `.omp_microtask.':

llvm_openmp.ll:(.text+0xf1): undefined reference to `omp_get_thread_num'

llvm_openmp.ll:(.text+0xf9): undefined reference to `omp_get_num_threads'

llvm_openmp.ll:(.text+0x101): undefined reference to `omp_get_max_threads'

llvm_openmp.ll:(.text+0x12d): undefined reference to `__kmpc_cancel_barrier'

its strange cuz when I dont invoke -emit-llvm and just compiler and link at
once with *clang(openmp) -fopenmp foo.c *the executable can be run with max
threads.

Appreciate any helps,

-Amir

On Wed, Nov 12, 2014 at 11:19 AM, Amir H. Ashouri <
amirhossein.ashouri at gmail.com> wrote:

> Thanks all for their responses. I re-compile the clang with OpenMP support
> and the library files and set the library paths and it worked finally. I
> might think as Alexey mentioned, that the CentOS was using the default
> clang to that matter before head.
>
> Regards,
>
> -Amir
>
> On Wed, Nov 12, 2014 at 11:55 AM, Jack Howarth <
> howarth.mailing.lists at gmail.com> wrote:
>
>> Amir,
>>     You didn't say what platform you are trying to use clang-omp on. If
>> it is OS X, the llvm34-3.4.2-2 fink package (http://finkproject.org) has
>> a port of the clang-omp changes at commit
>> 13e28835a005b44481387a32666ed39a7db58eb6 over the llvm 3.4.2 release. While
>> the fink llvm35 packaging isn't released yet, you can obtain the necessary
>> llvm35* packaging files to build it from
>> http://fink.cvs.sourceforge.net/viewvc/fink/experimental/fangism/finkinfo/.
>> This has a port of the clang-omp changes at commit 3f687cbc520a8b8f506d7941f0cebd6c5af1cef6 over
>> llvm 3.5.0 with the openmp trunk changes at r219214.
>>              Jack
>>
>> On Fri, Nov 7, 2014 at 3:22 PM, Amir H. Ashouri <
>> amirhossein.ashouri at gmail.com> wrote:
>>
>>> I did that.
>>>
>>> Downloaded and compiled with gcc, then export all the PATHs. Otherwise,
>>> It would have given me compile error because the "omp.h" is different here.
>>>
>>> -Amir
>>>
>>> On Fri, Nov 7, 2014 at 3:13 PM, Millad Ghane <millad.mg at gmail.com>
>>> wrote:
>>>
>>>> Hi,
>>>>
>>>> You haven't imported the openmp library to Clang yet. It simply ignores
>>>> the pragmas.
>>>>
>>>> Go to this link and follow the instructions.
>>>> clang-omp.github.io
>>>>
>>>>
>>>> Best Regards,
>>>> Millad
>>>>
>>>>
>>>> On Friday, November 7, 2014, Amir H. Ashouri <
>>>> amirhossein.ashouri at gmail.com> wrote:
>>>>
>>>>> Greetings,
>>>>>
>>>>> so I tried to use opennp with one of the latest version of clang, clang
>>>>> version 3.4.2 (tags/RELEASE_34/dot2-final). Followed the procedure to
>>>>> compilre and export the library PATHs, Compiling my hello.c using :
>>>>>
>>>>> clang -fopenmp hello.c
>>>>>
>>>>> and then running it, still it can't use more than 1 thread:
>>>>>
>>>>> Bash-4.1$ ./a.out Hello from thread 0, nthreads 1
>>>>>
>>>>> I tried to manually export export OMP_NUM_THREADS=8 but that didn't
>>>>> solve anything as well, As a workaround I define  #pragma omp
>>>>> parallel num_threads(#noofthreads) inside the source code but still
>>>>> the issue is there.
>>>>>
>>>>> Any suggestions would be appreciated.
>>>>>
>>>>>
>>>>> -Amir
>>>>>
>>>>>
>>>>> p.sl: This is the hello.c:
>>>>>
>>>>> #include <omp.h>#include <stdio.h>int main() {#pragma omp parallel
>>>>> printf("Hello from thread %d, nthreads %d\n", omp_get_thread_num(), omp_get_num_threads
>>>>>
>>>>>
>>>>
>>>> --
>>>> Sent from my iPhone
>>>>
>>>
>>>
>>> _______________________________________________
>>> Openmp-dev mailing list
>>> Openmp-dev at dcs-maillist2.engr.illinois.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/openmp-dev
>>>
>>>
>>
>
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