[Bug debug/42288] New: please emit empty .debug_aranges section

[Bug debug/42288] New: please emit empty .debug_aranges section

[tromey at gcc dot gnu dot org]

I have modified gdb to read the .debug_aranges section.
Currently, if this information does not exist for a
particular CU, gdb must scan the CU to find it.
This is necessary because there is no way to differentiate
between a section that is missing because it has no ranges,
and a section that is missing because it was stripped
or simply never created.

It would be helpful to gdb if gcc could emit .debug_aranges
even if there are no ranges to report.


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           Summary: please emit empty .debug_aranges section
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: tromey at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42288

[Bug debug/42288] please emit empty .debug_aranges section

[rth at gcc dot gnu dot org]

------- Comment #1 from rth at gcc dot gnu dot org  2009-12-06 22:31 -------
Reasonable.


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rth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |rth at gcc dot gnu dot org
                   |dot org                     |
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-12-06 22:31:12
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42288

[Bug debug/42288] please emit empty .debug_aranges section

[rth at gcc dot gnu dot org]

------- Comment #2 from rth at gcc dot gnu dot org  2009-12-07 02:04 -------
To be sure, you're keying off having *some* aranges entry with a reference
to a given CU in the debug_info section?  So:

Contents of the .debug_aranges section:

  Length:                   28
  Version:                  2
  Offset into .debug_info:  0x0
  Pointer Size:             8
  Segment Size:             0

    Address            Length
    0000000000000000 0000000000000000 

is exactly what you're looking for?


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rth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42288

[Bug debug/42288] please emit empty .debug_aranges section

[tromey at gcc dot gnu dot org]

------- Comment #3 from tromey at gcc dot gnu dot org  2009-12-07 15:57 -------
Yes, that's exactly what I would like.  Thanks.


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tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW
   Last reconfirmed|2009-12-06 22:31:12         |2009-12-07 15:57:12
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42288

[Bug debug/42288] please emit empty .debug_aranges section

[rth at gcc dot gnu dot org]

------- Comment #4 from rth at gcc dot gnu dot org  2009-12-07 16:19 -------
Created an attachment (id=19249)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19249&action=view)
Proposed patch

For the record, this is all that's needed for the above output.

I see quite a few gdb regressions vs F12 system compiler.  I suppose
that could just be gcc 4.5, but since F12 also includes VTA I would
hope that would not be the case...


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42288

[Bug debug/42288] please emit empty .debug_aranges section

[tromey at gcc dot gnu dot org]

------- Comment #5 from tromey at gcc dot gnu dot org  2009-12-08 17:58 -------
FWIW, I know that this patch will not affect the CVS gdb,
because that gdb never reads the .debug_aranges section.
I'll try this out using my branch today.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42288

[Bug debug/42288] please emit empty .debug_aranges section

[rth at gcc dot gnu dot org]

------- Comment #6 from rth at gcc dot gnu dot org  2009-12-15 17:36 -------
<tromey> rth: sorry... yeah, I tested the aranges patch and it worked for me. 
but it isn't clear we will need it now, we're discussing some form of caching
w/ gdb rather than using the index sections
<rth> ok.  i'll leave the patch alone until you tell me we need it.


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rth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |SUSPENDED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42288

[Bug debug/42288] please emit empty .debug_aranges section

[mark at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42288

Mark Wielaard <mark at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|SUSPENDED                   |NEW
                 CC|                            |mark at gcc dot gnu.org

--- Comment #7 from Mark Wielaard <mark at gcc dot gnu.org> 2011-04-21 15:33:09 UTC ---
We discussed this a bit on the elfutils list WRT the dwarflint checks we have.
And the consensus seems to be that it is more convenient to actually have an
.aranges entry for each CU.
https://fedorahosted.org/pipermail/elfutils-devel/2011-April/002024.html

Could the patch be resurrected?

[Bug debug/42288] please emit empty .debug_aranges section

[mark at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42288

Mark Wielaard <mark at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED

--- Comment #8 from Mark Wielaard <mark at gcc dot gnu.org> 2011-09-26 18:15:52 UTC ---
Author: mark
Date: Tue May  3 19:36:08 2011
New Revision: 173340

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=173340
Log:
PR42288 emit empty .debug_aranges section.

* dwarf2out.c (dwarf2out_finish): Always call output_aranges ()
  when info_section_emitted.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/dwarf2out.c