llvm dev - Jun 2017 - [CUDA] Lost debug information when compiling CUDA code

Hi,


I needed to debug some CUDA code in my project; however, although I used -g when
compiling the source code, no source-level information is available in cuda-gdb
or cuda-memcheck.


Specifically, below is what I did:


1) For a CUDA file a.cu, generate IR files: clang++ -g -emit-llvm
--cuda-gpu-arch=sm_35 -c a.cu;
2) Instrument the device code a-cuda-nvptx64-nvidia-cuda-sm_35.bc (generated in
the previous step), inserting a call to a hook function before each device
memory access.  The hook function is defined in another file, b.cu.  Let's
say we get a file named intrumented-a-device.bc after this step;
3) Generate IR files for b.cu: clang++ -g -emit-llvm --cuda-gpu-arch=sm_35 -c
b.cu;
4) Link instrumented-a.device.bc with the device code generated for b.cu:
llvm-link intrumented-a-device.bc b-cuda-nvptx64-nvidia-cuda-sm_35.bc -o
ab-device.bc;
5) Use llc, ptxas & fatbinary on ab-device.bc to get ab-device.ptx,
ab-device.o & ab-device.fatbin;
6) Call clang again the generate the host object file ab.o, with ab-device.o
& ab-device.fatbin embedded;
7) Link against libraries and get the final binary: a.out.


The binary a.out fails with an exception I when run it; but when I try to debug
it with cuda-gdb or cuda-memcheck, no source information was available.  Why?


Thanks!
Yuanfeng Peng
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20170614/1bfdd28e/attachment.html>

Is source level information present in generated IR files?

On Wed, Jun 14, 2017 at 12:29 PM, Yuanfeng Peng via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi,
>
> I needed to debug some CUDA code in my project; however, although I used
> -g when compiling the source code, no source-level information is available
> in cuda-gdb or cuda-memcheck.
>
> Specifically, below is what I did:
>
> 1) For a CUDA file a.cu, generate IR files: clang++ -g -emit-llvm
> --cuda-gpu-arch=sm_35 -c a.cu;
> 2) Instrument the device code a-cuda-nvptx64-nvidia-cuda-sm_35.bc
> (generated in the previous step), inserting a call to a hook function
> before each device memory access.  The hook function is defined in another
> file, b.cu.  Let's say we get a file named intrumented-a-device.bc
after
> this step;
> 3) Generate IR files for b.cu: clang++ -g -emit-llvm
> --cuda-gpu-arch=sm_35 -c b.cu;
> 4) Link instrumented-a.device.bc with the device code generated for b.cu:
> llvm-link intrumented-a-device.bc b-cuda-nvptx64-nvidia-cuda-sm_35.bc -o
> ab-device.bc;
> 5) Use llc, ptxas & fatbinary on ab-device.bc to get ab-device.ptx,
> ab-device.o & ab-device.fatbin;
> 6) Call clang again the generate the host object file ab.o, with
> ab-device.o & ab-device.fatbin embedded;
> 7) Link against libraries and get the final binary: a.out.
>
> The binary a.out fails with an exception I when run it; but when I try to
> debug it with cuda-gdb or cuda-memcheck, no source information was
> available.  Why?
>
> Thanks!
> Yuanfeng Peng
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>

-- 
*Disclaimer: Views, concerns, thoughts, questions, ideas expressed in this
mail are of my own and my employer has no take in it. *
Thank You.
Madhur D. Amilkanthwar
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20170614/c871ad58/attachment-0001.html>

Yes, I've inspected all the intermediate IR files and source level
information is present in them.


------------------ Original ------------------
From:  "Madhur Amilkanthwar";<madhur13490 at gmail.com>;
Send time: Wednesday, Jun 14, 2017 5:03 PM
To: "Yuanfeng Peng"<yuanfengp at foxmail.com>; 
Cc: "via llvm-dev"<llvm-dev at lists.llvm.org>; 
Subject:  Re: [llvm-dev] [CUDA] Lost debug information when compiling CUDA code



Is source level information present in generated IR files? 

On Wed, Jun 14, 2017 at 12:29 PM, Yuanfeng Peng via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
Hi,


I needed to debug some CUDA code in my project; however, although I used -g when
compiling the source code, no source-level information is available in cuda-gdb
or cuda-memcheck.


Specifically, below is what I did:


1) For a CUDA file a.cu, generate IR files: clang++ -g -emit-llvm
--cuda-gpu-arch=sm_35 -c a.cu;
2) Instrument the device code a-cuda-nvptx64-nvidia-cuda-sm_35.bc (generated in
the previous step), inserting a call to a hook function before each device
memory access.  The hook function is defined in another file, b.cu.  Let's
say we get a file named intrumented-a-device.bc after this step;
3) Generate IR files for b.cu: clang++ -g -emit-llvm --cuda-gpu-arch=sm_35 -c
b.cu;
4) Link instrumented-a.device.bc with the device code generated for b.cu:
llvm-link intrumented-a-device.bc b-cuda-nvptx64-nvidia-cuda-sm_35.bc -o
ab-device.bc;
5) Use llc, ptxas & fatbinary on ab-device.bc to get ab-device.ptx,
ab-device.o & ab-device.fatbin;
6) Call clang again the generate the host object file ab.o, with ab-device.o
& ab-device.fatbin embedded;
7) Link against libraries and get the final binary: a.out.


The binary a.out fails with an exception I when run it; but when I try to debug
it with cuda-gdb or cuda-memcheck, no source information was available.  Why?


Thanks!
Yuanfeng Peng
 
 
_______________________________________________
 LLVM Developers mailing list
 llvm-dev at lists.llvm.org
 http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
 





-- 
Disclaimer: Views, concerns, thoughts, questions, ideas expressed in this mail
are of my own and my employer has no take in it.

Thank You.
Madhur D. Amilkanthwar
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20170614/a23dd311/attachment.html>

On 06/14/2017 02:59 AM, Yuanfeng Peng via llvm-dev
wrote:
> Hi,
> 
> I needed to debug some CUDA code in my project; however, although I used -g
when compiling the source code, no source-level information is available in
cuda-gdb or cuda-memcheck.
> 
The NVPTX backend in LLVM does not support DWARF emission.

-Tom
> Specifically, below is what I did:
> 
> 1) For a CUDA file a.cu, generate IR files: clang++ -g -emit-llvm
--cuda-gpu-arch=sm_35 -c a.cu;
> 2) Instrument the device code a-cuda-nvptx64-nvidia-cuda-sm_35.bc
(generated in the previous step), inserting a call to a hook function before
each device memory access.  The hook function is defined in another file, b.cu. 
Let's say we get a file named intrumented-a-device.bc after this step;
> 3) Generate IR files for b.cu: clang++ -g -emit-llvm --cuda-gpu-arch=sm_35
-c b.cu;
> 4) Link instrumented-a.device.bc with the device code generated for b.cu:
llvm-link intrumented-a-device.bc b-cuda-nvptx64-nvidia-cuda-sm_35.bc -o
ab-device.bc;
> 5) Use llc, ptxas & fatbinary on ab-device.bc to get ab-device.ptx,
ab-device.o & ab-device.fatbin;
> 6) Call clang again the generate the host object file ab.o, with
ab-device.o & ab-device.fatbin embedded;
> 7) Link against libraries and get the final binary: a.out.
> 
> The binary a.out fails with an exception I when run it; but when I try to
debug it with cuda-gdb or cuda-memcheck, no source information was available. 
Why?
> 
> Thanks!
> Yuanfeng Peng
>  
> 
> 
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>

Hi Tom,


Thanks for the response!  I wonder whether there's any other way that I can
get the source level information when using cuda-gdb to debug a binary compiled
by LLVM? Or is there any way to feed the IR files to NVCC and get a binary with
the debug info I need?


Thanks!
Yuanfeng




------------------ Original ------------------
From:  "Tom Stellard";<tstellar at redhat.com>;
Send time: Wednesday, Jun 14, 2017 9:06 PM
To: "Yuanfeng Peng"<yuanfengp at foxmail.com>; "via
llvm-dev"<llvm-dev at lists.llvm.org>;

Subject:  Re: [llvm-dev] [CUDA] Lost debug information when compiling CUDA code



On 06/14/2017 02:59 AM, Yuanfeng Peng via llvm-dev
wrote:
> Hi,
> 
> I needed to debug some CUDA code in my project; however, although I used -g
when compiling the source code, no source-level information is available in
cuda-gdb or cuda-memcheck.
> 
The NVPTX backend in LLVM does not support DWARF emission.

-Tom
> Specifically, below is what I did:
> 
> 1) For a CUDA file a.cu, generate IR files: clang++ -g -emit-llvm
--cuda-gpu-arch=sm_35 -c a.cu;
> 2) Instrument the device code a-cuda-nvptx64-nvidia-cuda-sm_35.bc
(generated in the previous step), inserting a call to a hook function before
each device memory access.  The hook function is defined in another file, b.cu. 
Let's say we get a file named intrumented-a-device.bc after this step;
> 3) Generate IR files for b.cu: clang++ -g -emit-llvm --cuda-gpu-arch=sm_35
-c b.cu;
> 4) Link instrumented-a.device.bc with the device code generated for b.cu:
llvm-link intrumented-a-device.bc b-cuda-nvptx64-nvidia-cuda-sm_35.bc -o
ab-device.bc;
> 5) Use llc, ptxas & fatbinary on ab-device.bc to get ab-device.ptx,
ab-device.o & ab-device.fatbin;
> 6) Call clang again the generate the host object file ab.o, with
ab-device.o & ab-device.fatbin embedded;
> 7) Link against libraries and get the final binary: a.out.
> 
> The binary a.out fails with an exception I when run it; but when I try to
debug it with cuda-gdb or cuda-memcheck, no source information was available. 
Why?
> 
> Thanks!
> Yuanfeng Peng
>  
> 
> 
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20170614/68407855/attachment.html>