Re: Non-dwarf blocks detected by valgrind

Re: Non-dwarf blocks detected by valgrind

[Thomas Koenig]

Hi Tobias,

>> Does this constitute a regression?
> 
>  From your description, yes. Can you give more details how to reproduce it?

$ cat hello.f90
   print *,"Hello, world!"
end
$ valgrind --version
valgrind-3.15.0
$ gfortran -g hello.f90
$ valgrind ./a.out
[...]
--4184-- WARNING: Serious error when reading debug info
--4184-- When reading debug info from /home/ig25/lib64/libgfortran.so.5.0.0:
--4184-- Ignoring non-Dwarf2/3/4 block in .debug_info
--4184-- WARNING: Serious error when reading debug info
--4184-- When reading debug info from /home/ig25/lib64/libgfortran.so.5.0.0:

[...]

--4184-- WARNING: Serious error when reading debug info
--4184-- When reading debug info from /home/ig25/lib64/libgcc_s.so.1:
--4184-- Ignoring non-Dwarf2/3/4 block in .debug_info


[...]

--4184-- WARNING: Serious error when reading debug info
--4184-- When reading debug info from /home/ig25/lib64/libquadmath.so.0.0.0:
--4184-- Ignoring non-Dwarf2/3/4 block in .debug_info

So, the problem (at least for me) is that libgfortran and
other libraries are built in a format that valgrind can not
understand, so it becomes much harder to debug libgfortran :-(

Is there a way to configure the build so that the old debug
format is used for the libraries?

Best regards

	Thomas

Re: Non-dwarf blocks detected by valgrind

[Mark Wielaard]

Hi,

On Mon, 2021-01-25 at 15:05 +0100, Thomas Koenig via Gcc wrote:
> $ valgrind --version
> valgrind-3.15.0
> $ gfortran -g hello.f90
> $ valgrind ./a.out
> [...]
> --4184-- WARNING: Serious error when reading debug info
> --4184-- When reading debug info from
> /home/ig25/lib64/libgfortran.so.5.0.0:
> --4184-- Ignoring non-Dwarf2/3/4 block in .debug_info
> --4184-- WARNING: Serious error when reading debug info
> --4184-- When reading debug info from
> /home/ig25/lib64/libgfortran.so.5.0.0:
> 
> [...]
> 
> --4184-- WARNING: Serious error when reading debug info
> --4184-- When reading debug info from /home/ig25/lib64/libgcc_s.so.1:
> --4184-- Ignoring non-Dwarf2/3/4 block in .debug_info
> 
> 
> [...]
> 
> --4184-- WARNING: Serious error when reading debug info
> --4184-- When reading debug info from
> /home/ig25/lib64/libquadmath.so.0.0.0:
> --4184-- Ignoring non-Dwarf2/3/4 block in .debug_info
> 
> So, the problem (at least for me) is that libgfortran and
> other libraries are built in a format that valgrind can not
> understand, so it becomes much harder to debug libgfortran :-(

I have a patch for that:
https://code.wildebeest.org/git/user/mjw/valgrind/commit/?h=dwarf5

It needs a little bit more cleanup, but should already work as
expected.

Cheers,

Mark

Re: Non-dwarf blocks detected by valgrind

[Tobias Burnus]

Hi Thomas,

which binutil version do you have? I am asking because Jakub just
submitted:
https://gcc.gnu.org/pipermail/gcc-patches/2021-January/564206.html

If that does not help, it might be that valgrind simply does not like
the DWARF which GCC now produces by default.

Defaulting to 4: Well, one way would be to use '4' in "init(5)" of
"gdwarf-" in gcc/common.opt.

Tobias

PS: When checking myself, I did not set LD_LIBRARY_PATH, using the *.so
of the Linux distro; hence, I might have missed the issue you are seeing.

On 25.01.21 15:05, Thomas Koenig via Fortran wrote:
>
> Hi Tobias,
>
>>> Does this constitute a regression?
>>
>>  From your description, yes. Can you give more details how to
>> reproduce it?
>
> $ cat hello.f90
>   print *,"Hello, world!"
> end
> $ valgrind --version
> valgrind-3.15.0
> $ gfortran -g hello.f90
> $ valgrind ./a.out
> [...]
> --4184-- WARNING: Serious error when reading debug info
> --4184-- When reading debug info from
> /home/ig25/lib64/libgfortran.so.5.0.0:
> --4184-- Ignoring non-Dwarf2/3/4 block in .debug_info
> --4184-- WARNING: Serious error when reading debug info
> --4184-- When reading debug info from
> /home/ig25/lib64/libgfortran.so.5.0.0:
>
> [...]
>
> --4184-- WARNING: Serious error when reading debug info
> --4184-- When reading debug info from /home/ig25/lib64/libgcc_s.so.1:
> --4184-- Ignoring non-Dwarf2/3/4 block in .debug_info
>
>
> [...]
>
> --4184-- WARNING: Serious error when reading debug info
> --4184-- When reading debug info from
> /home/ig25/lib64/libquadmath.so.0.0.0:
> --4184-- Ignoring non-Dwarf2/3/4 block in .debug_info
>
> So, the problem (at least for me) is that libgfortran and
> other libraries are built in a format that valgrind can not
> understand, so it becomes much harder to debug libgfortran :-(
>
> Is there a way to configure the build so that the old debug
> format is used for the libraries?
>
> Best regards
>
>     Thomas
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Re: Non-dwarf blocks detected by valgrind

[Thomas Koenig]

Hi Tobias,

> which binutil version do you have?

$ as -v
GNU assembler version 2.35.1 (x86_64-suse-linux) using BFD version (GNU 
Binutils; openSUSE Leap 15.1) 2.35.1.20201123-lp151.3.12


> I am asking because Jakub just
> submitted:
> https://gcc.gnu.org/pipermail/gcc-patches/2021-January/564206.html

Looks like this could be the issue.  I'll re-check once that patch
has hit the trunk.

Best regards

	Thomas

Re: Non-dwarf blocks detected by valgrind

[Mark Wielaard]

On Mon, 2021-01-25 at 15:38 +0100, Mark Wielaard wrote:
> On Mon, 2021-01-25 at 15:05 +0100, Thomas Koenig via Gcc wrote:
> > --4184-- WARNING: Serious error when reading debug info
> > --4184-- When reading debug info from
> > /home/ig25/lib64/libquadmath.so.0.0.0:
> > --4184-- Ignoring non-Dwarf2/3/4 block in .debug_info
> > 
> > So, the problem (at least for me) is that libgfortran and
> > other libraries are built in a format that valgrind can not
> > understand, so it becomes much harder to debug libgfortran :-(
> 
> I have a patch for that:
> https://code.wildebeest.org/git/user/mjw/valgrind/commit/?h=dwarf5
> 
> It needs a little bit more cleanup, but should already work as
> expected.

Cleaned up and submitted upstream:
https://bugs.kde.org/show_bug.cgi?id=432102
Also backported to Fedora 34 valgrind package:
https://bodhi.fedoraproject.org/updates/FEDORA-2021-6335fad95d

Cheers,

Mark