sh_link not set for section `.ARM.exidx'

sh_link not set for section `.ARM.exidx'

[Richard Purdie]

Hi,

I've been making ARM EABI builds with a toolchain with binutils
2.17.50.0.5. The build system splits debug symbols into separate
binaries by doing:

objcopy --only-keep-debug x .debug/x
strip x
objcopy --add-gnu-debuglink=.debug/x x

as per the objcopy manpage and which worked find under the previous ABI.
Under EABI each time it does this (and each time libbfd touches a debug
binary on device) I see:

BFD: x: warning: sh_link not set for section `.ARM.exidx'

The results from objdump look interesting:

objdump -x striped-binary:

12 .text 000358e0 0000a1b8 0000a1b8 000021b8 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
13 .fini 00000010 0003fa98 0003fa98 00037a98 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
14 .rodata 0000a328 0003faa8 0003faa8 00037aa8 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
15 .ARM.exidx 00000008 00049dd0 00049dd0 00041dd0 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
16 .eh_frame 00000004 00049dd8 00049dd8 00041dd8 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
17 .init_array 00000004 00051f04 00051f04 00041f04 2**2
CONTENTS, ALLOC, LOAD, DATA
18 .fini_array 00000004 00051f08 00051f08 00041f08 2**2
CONTENTS, ALLOC, LOAD, DATA

objdump -x debug-binary:

12 .text 000358e0 0000a1b8 0000a1b8 00000134 2**2
ALLOC, READONLY, CODE
13 .fini 00000010 0003fa98 0003fa98 00000134 2**2
ALLOC, READONLY, CODE
14 .rodata 0000a328 0003faa8 0003faa8 00000134 2**3
ALLOC, READONLY
15 .ARM.exidx 00000008 00049dd0 00049dd0 00000134 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
16 .eh_frame 00000004 00049dd8 00049dd8 00000134 2**2
ALLOC, READONLY
17 .init_array 00000004 00051f04 00051f04 00001f04 2**2
ALLOC
18 .fini_array 00000004 00051f08 00051f08 00001f04 2**2

since .ARM.exidx still has CONTENTS/DARA/LOAD flags yet its file offset
has changed to 00000134 which I'm guessing means it was emptied. I'm
unable to remove those flags with objcopy.

Is there anything I can do to clear this error up? I wondered about just
removing that section from the debug libraries but I don't know what
implications that might have and whether there are any references that
could cause problems. I would prefer to solve this properly...

Does anyone have any ideas?

Cheers,

Richard

Re: sh_link not set for section `.ARM.exidx'

[Alan Modra]

Please send me an arm-eabi binary that shows this problem and I'll
take a look.

-- 
Alan Modra
Australia Development Lab, IBM

Re: sh_link not set for section `.ARM.exidx'

[Richard Purdie]

On Thu, 2007-08-09 at 09:59 +0930, Alan Modra wrote:
> Please send me an arm-eabi binary that shows this problem and I'll
> take a look.

I've put an example binary online in case anyone else wants to look too:

http://www.rpsys.net/openzaurus/temp/binutils/apmd

and stripped/debug versions of this showing the problem:

http://www.rpsys.net/openzaurus/temp/binutils/apmd-debug
http://www.rpsys.net/openzaurus/temp/binutils/apmd-stripped

Thanks,

Richard

Re: sh_link not set for section `.ARM.exidx'

[Alan Modra]

On Thu, Aug 09, 2007 at 09:35:25AM +0100, Richard Purdie wrote:
> On Thu, 2007-08-09 at 09:59 +0930, Alan Modra wrote:
> > Please send me an arm-eabi binary that shows this problem and I'll
> > take a look.
> 
> I've put an example binary online in case anyone else wants to look too:
> 
> http://www.rpsys.net/openzaurus/temp/binutils/apmd

Looks to be no problem with latest CVS binutils.

-- 
Alan Modra
Australia Development Lab, IBM

Re: sh_link not set for section `.ARM.exidx'

[Richard Purdie]

On Thu, 2007-08-09 at 21:38 +0930, Alan Modra wrote:
> On Thu, Aug 09, 2007 at 09:35:25AM +0100, Richard Purdie wrote:
> > On Thu, 2007-08-09 at 09:59 +0930, Alan Modra wrote:
> > > Please send me an arm-eabi binary that shows this problem and I'll
> > > take a look.
> > 
> > I've put an example binary online in case anyone else wants to look too:
> > 
> > http://www.rpsys.net/openzaurus/temp/binutils/apmd
> 
> Looks to be no problem with latest CVS binutils.

Thanks for testing that, after quite a bit of effort I managed to build
a suitable cross binutils and can confirm it doesn't show the problem.

To make binutils cvs build I had to disable libgloss and rda. Are those
failures interesting or a known issue?

I can't see how rda could ever cross compile given its configure
script...

Cheers,

Richard

Re: sh_link not set for section `.ARM.exidx'

[Daniel Jacobowitz]

On Fri, Aug 10, 2007 at 12:32:41PM +0100, Richard Purdie wrote:
> Thanks for testing that, after quite a bit of effort I managed to build
> a suitable cross binutils and can confirm it doesn't show the problem.
> 
> To make binutils cvs build I had to disable libgloss and rda. Are those
> failures interesting or a known issue?
> 
> I can't see how rda could ever cross compile given its configure
> script...

You can check out just binutils, rather than the whole "src"
repository, or get a binutils snapshot from the FTP site - then those
(and many other directories) will not be included.  They're part of
different programs.

-- 
Daniel Jacobowitz
CodeSourcery

Re: sh_link not set for section `.ARM.exidx'

[Richard Purdie]

On Fri, 2007-08-10 at 08:51 -0400, Daniel Jacobowitz wrote:
> You can check out just binutils, rather than the whole "src"
> repository, or get a binutils snapshot from the FTP site - then those
> (and many other directories) will not be included.  They're part of
> different programs.

Thanks for the tip, I need bfd and some of the other bits but I've now
realised I can just remove the directories I don't want which is neater
than what I was trying before!

Cheers,

Richard