[Bug debug/24444] New: [4.1 regression] invalid register in debug info

[Bug debug/24444] New: [4.1 regression] invalid register in debug info

[schwab at suse dot de]

$ gcc -S -g -dA auxv.c
$ grep -A1 regx auxv.s
        data1   0x90    // DW_OP_regx
        .uleb128 0xffffffff
--
        data1   0x90    // DW_OP_regx
        .uleb128 0xffffffff
--
        data1   0x90    // DW_OP_regx
        .uleb128 0xffffffff


-- 
           Summary: [4.1 regression] invalid register in debug info
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Keywords: wrong-debug
          Severity: normal
          Priority: P2
         Component: debug
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: schwab at suse dot de
GCC target triplet: ia64-suse-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1 regression] invalid register in debug info

[schwab at suse dot de]

------- Comment #1 from schwab at suse dot de  2005-10-19 17:03 -------
Created an attachment (id=10025)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10025&action=view)
Testcase


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1 regression] invalid register in debug info

[wilson at gcc dot gnu dot org]

------- Comment #2 from wilson at gcc dot gnu dot org  2005-10-19 23:34 -------
This was broken by Richard Henderson's patch that added the
convert_cfa_to_loc_list function.  The thread for the patch starts here.  It
was finally installed Sept 7.
    http://gcc.gnu.org/ml/gcc-patches/2005-08/msg01176.html

The flaw with the patch is that Richard modified dwarf2out.c to use the dwarf
unwind info unconditionally.  However, it is only available for targets that
define DWARF2_UNWIND_INFO.  For all other targets, we now get incorrect debug
info.

IA-64 of course has its own unwind info, IA-64 unwind info, as defined by the
IA-64 ABI, and does not need or want to use dwarf unwind info.

I haven't yet tried to comprehend Richard's patch.  It is a big one.  Hence, I
do not yet have a suggested fix.

I suspect the fix may be as simple as putting a #ifdef DWARF2_UNWIND_INFO test
in gen_subprogram_die around the convert_cfa_to_loc_list call, and putting the
old code back in the #else case.

Worst case, we need to write equivalent code that knows how to convert IA-64
unwind info into a location list.  However, given that gdb already knows how to
use libunwind, and any other self-respecting IA-64 debugger should also already
be using the IA-64 unwind info, it isn't clear to me that we need to do
anything in gcc here.  We can not make the same assumption about dwarf2 unwind
info, as this isn't part of the ABI for most targets, so Richard's patch does
make sense there.


-- 

wilson at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-10-19 23:34:35
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1 regression] invalid register in debug info

[wilson at gcc dot gnu dot org]

------- Comment #3 from wilson at gcc dot gnu dot org  2005-10-20 05:09 -------
It looks a little more complicated than I hoped, as Richard deleted code in
var-tracking.c that was used by the old code in dwarf2out.c that we need for
IA-64 and other non-DWARF2_UNWIND_INFO targets.


-- 

wilson at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rth at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1 regression] invalid register in debug info

[rth at gcc dot gnu dot org]

------- Comment #4 from rth at gcc dot gnu dot org  2005-10-20 08:35 -------
Well, the ideal fix is to make use of the dwarf3 DW_OP_call_frame_cfa
directive, and let the debugger get the CFA information from the ia64
unwind info.  Similarly for the arm eabi unwind info.

I'm not sure what a good short-term fix is.  Perhaps, as you suggest,
putting some code back for TARGET_UNWIND_INFO targets.

On the other hand, both ia64 and arm are ACCUMULATE_OUTGOING_ARGS targets,
which means that they don't *need* all that tracking info to find the CFA.
For any function that gcc generates, the CFA starts as SP+OFFSET1 and changes
exactly once to either SP+OFFSET2 or FP+OFFSET3.  Which means that we could 
fairly easily acquire this info (plus a label of the transition point) from
a target hook.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1 regression] invalid register in debug info

[wilson at gcc dot gnu dot org]

-- 

wilson at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1 regression] invalid register in debug info

[mmitchel at gcc dot gnu dot org]

------- Comment #5 from mmitchel at gcc dot gnu dot org  2005-10-31 06:32 -------
I guess I'll leave this as P2, but I really do think we should find a fix
before the next release, for the affected targets.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1 regression] invalid register in debug info

[wilson at gcc dot gnu dot org]

------- Comment #6 from wilson at gcc dot gnu dot org  2005-10-31 23:39 -------
Subject: Bug 24444

Author: wilson
Date: Mon Oct 31 23:39:29 2005
New Revision: 106299

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=106299
Log:
Restore old AT_frame_base code for targets that don't use dwarf2 unwind info.
Partial fix.
PR debug/24444
* dwarf2out.c (convert_cfa_to_loc_list): Put inside DWARF2_UNWIND_INFO
ifdef.  Put ifdefs around call in gen_subprogram_die.
(compute_frame_pointer_to_cfa_displacement): Likewise.
(gen_subprogram_die): Restore old code for when DWARF2_UNWIND_INFO is
not defined.

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


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1 regression] invalid register in debug info

[wilson at gcc dot gnu dot org]

------- Comment #7 from wilson at gcc dot gnu dot org  2005-10-31 23:46 -------
This is partially fixed.  The debug info is correct enough to make the gdb
testsuite happy, but we are lacking correct info for the frame_base in the
prologue and epilogue.  That used to be computed by code in var-tracking.c, but
that code was removed.  As Richard mentioned, we can probably get full frame
base info back by using a hook.  I have left that for a later patch.

Since the remaining problem is not serious, I am changing the target milestone
to 4.2.


-- 

wilson at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |wilson at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2005-10-19 23:34:35         |2005-10-31 23:46:00
               date|                            |
   Target Milestone|4.1.0                       |4.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1 regression] invalid register in debug info

[wilson at gcc dot gnu dot org]

------- Comment #8 from wilson at gcc dot gnu dot org  2005-11-01 01:16 -------
I see that we are using the priority field now, so let's put the 4.1 target
milestone back and set priority to p4 to indicate this is a regression, but not
a serious one blocking the release.


-- 

wilson at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P2                          |P4
   Target Milestone|4.2.0                       |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1 regression] invalid register in debug info

[drow at false dot org]

------- Comment #9 from drow at gcc dot gnu dot org  2005-11-15 20:58 -------
Subject: Re:  [4.1 regression] invalid register in debug info

On Thu, Oct 20, 2005 at 08:35:59AM -0000, rth at gcc dot gnu dot org wrote:
> Well, the ideal fix is to make use of the dwarf3 DW_OP_call_frame_cfa
> directive, and let the debugger get the CFA information from the ia64
> unwind info.  Similarly for the arm eabi unwind info.

Note that this may be a good solution for ia64, but it really is not
for ARM.  ARM unwind information is only usable by the debugger in very
few cases, because everything interesting is handled by a personality
routine; it's only if you use one of the standard table formats (which
GCC does) that the debugger can decode it.

But we do still emit .debug_frame for ARM, and the debugger does use
that.  So presumably that's plenty to use DW_OP_call_frame_cfa.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1/4.2 regression] invalid register in debug info

[aoliva at gcc dot gnu dot org]

------- Comment #10 from aoliva at gcc dot gnu dot org  2006-02-03 08:40 -------
Patch for the IA64 debug info regression posted at
http://gcc.gnu.org/ml/gcc-patches/2006-02/msg00197.html


-- 

aoliva at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |aoliva at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1/4.2 regression] invalid register in debug info

[pinskia at gcc dot gnu dot org]

------- Comment #11 from pinskia at gcc dot gnu dot org  2006-02-03 18:49 -------
Patch posted:
http://gcc.gnu.org/ml/gcc-patches/2006-02/msg00197.html


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|                            |http://gcc.gnu.org/ml/gcc-
                   |                            |patches/2006-
                   |                            |02/msg00197.html
           Keywords|                            |patch


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1/4.2 regression] invalid register in debug info

[aoliva at gcc dot gnu dot org]

------- Comment #12 from aoliva at gcc dot gnu dot org  2006-02-04 22:08 -------
Subject: Bug 24444

Author: aoliva
Date: Sat Feb  4 22:08:04 2006
New Revision: 110594

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110594
Log:
PR debug/24444
* config/ia64/ia64.c: Include debug.h.
(MAX_ARTIFICIAL_LABEL_BYTES): New.
(ia64_label_after_insn, ia64_dwarf2out_def_steady_cfa): New.
(IA64_CHANGE_CFA_IN_EPILOGUE): Define to 0.
(process_epilogue, process_set, process_for_unwind_directive):
Output unwind info only if requested.  Add CFA info if requested.
Add new arguments as needed.  Adjust callers.
* config/ia64/ia64.h (ARG_POINTER_CFA_OFFSET): Override
incorrect default.
(DWARF2_FRAME_INFO): Define to zero.
* config/ia64/unwind-ia64.c: Remove code that compensated for
the CFA offset error fixed above.
* config/ia64/t-ia64 (ia64.o): Depend on debug.h.
* dwarf2out.c (DWARF2_FRAME_INFO): Define default.
(dwarf2out_do_frame): Require nonzero DWARF2_UNWIND_INFO for
-funwind-tables and -fexceptions to enable frame info.
(dwarf2out_frame_init): Define initial CFA even if
DWARF2_UNWIND_INFO is disabled.  Call initial_return_save if
DWARF2_UNWIND_INFO is nonzero, not just defined.
(dwarf2out_frame_finish): Output non-EH call frame info only
if DWARF2_FRAME_INFO is nonzero.
(convert_cfa_to_loc_list,
compute_frame_pointer_to_cfa_displacement): Define even if
unwind info is not supported.
(gen_subprogram_die): Use the above unconditionally.  Remove
legacy alternate code.
* toplev.c (compile_file): Compile in call to
dwarf2out_frame_finish if DWARF2_DEBUGGING_INFO is defined.
(lang_dependent_init): Ditto for dwarf2out_frame_init.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/ia64/ia64.c
    trunk/gcc/config/ia64/ia64.h
    trunk/gcc/config/ia64/t-ia64
    trunk/gcc/config/ia64/unwind-ia64.c
    trunk/gcc/dwarf2out.c
    trunk/gcc/toplev.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1/4.2 regression] invalid register in debug info

[aoliva at gcc dot gnu dot org]

------- Comment #13 from aoliva at gcc dot gnu dot org  2006-02-04 22:13 -------
Subject: Bug 24444

Author: aoliva
Date: Sat Feb  4 22:13:20 2006
New Revision: 110597

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110597
Log:
PR debug/24444
* config/ia64/ia64.c: Include debug.h.
(MAX_ARTIFICIAL_LABEL_BYTES): New.
(ia64_label_after_insn, ia64_dwarf2out_def_steady_cfa): New.
(IA64_CHANGE_CFA_IN_EPILOGUE): Define to 0.
(process_epilogue, process_set, process_for_unwind_directive):
Output unwind info only if requested.  Add CFA info if requested.
Add new arguments as needed.  Adjust callers.
* config/ia64/ia64.h (ARG_POINTER_CFA_OFFSET): Override
incorrect default.
(DWARF2_FRAME_INFO): Define to zero.
* config/ia64/unwind-ia64.c: Remove code that compensated for
the CFA offset error fixed above.
* config/ia64/t-ia64 (ia64.o): Depend on debug.h.
* dwarf2out.c (DWARF2_FRAME_INFO): Define default.
(dwarf2out_do_frame): Require nonzero DWARF2_UNWIND_INFO for
-funwind-tables and -fexceptions to enable frame info.
(dwarf2out_frame_init): Define initial CFA even if
DWARF2_UNWIND_INFO is disabled.  Call initial_return_save if
DWARF2_UNWIND_INFO is nonzero, not just defined.
(dwarf2out_frame_finish): Output non-EH call frame info only
if DWARF2_FRAME_INFO is nonzero.
(convert_cfa_to_loc_list,
compute_frame_pointer_to_cfa_displacement): Define even if
unwind info is not supported.
(gen_subprogram_die): Use the above unconditionally.  Remove
legacy alternate code.
* toplev.c (compile_file): Compile in call to
dwarf2out_frame_finish if DWARF2_DEBUGGING_INFO is defined.
(lang_dependent_init): Ditto for dwarf2out_frame_init.

Modified:
    branches/gcc-4_1-branch/gcc/ChangeLog
    branches/gcc-4_1-branch/gcc/config/ia64/ia64.c
    branches/gcc-4_1-branch/gcc/config/ia64/ia64.h
    branches/gcc-4_1-branch/gcc/config/ia64/t-ia64
    branches/gcc-4_1-branch/gcc/config/ia64/unwind-ia64.c
    branches/gcc-4_1-branch/gcc/dwarf2out.c
    branches/gcc-4_1-branch/gcc/toplev.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1/4.2 regression] invalid register in debug info

[pinskia at gcc dot gnu dot org]

------- Comment #14 from pinskia at gcc dot gnu dot org  2006-02-04 22:23 -------
Fixed.


-- 

pinskia at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1/4.2 regression] invalid register in debug info

[jakub at gcc dot gnu dot org]

------- Comment #15 from jakub at gcc dot gnu dot org  2006-02-07 06:51 -------
Subject: Bug 24444

Author: jakub
Date: Tue Feb  7 06:51:39 2006
New Revision: 110688

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110688
Log:
2006-02-07  Alexandre Oliva  <aoliva@redhat.com>

        PR debug/24444
        * config/ia64/unwind-ia64.c: Revert last change.
        * config/ia64/ia64.h (ARG_POINTER_CFA_OFFSET): Removed.
        (INCOMING_FRAME_SP_OFFSET): Define.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/ia64/ia64.h
    trunk/gcc/config/ia64/unwind-ia64.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1/4.2 regression] invalid register in debug info

[jakub at gcc dot gnu dot org]

------- Comment #16 from jakub at gcc dot gnu dot org  2006-02-07 06:52 -------
Subject: Bug 24444

Author: jakub
Date: Tue Feb  7 06:52:17 2006
New Revision: 110689

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110689
Log:
2006-02-07  Alexandre Oliva  <aoliva@redhat.com>

        PR debug/24444
        * config/ia64/unwind-ia64.c: Revert last change.
        * config/ia64/ia64.h (ARG_POINTER_CFA_OFFSET): Removed.
        (INCOMING_FRAME_SP_OFFSET): Define.

Modified:
    branches/gcc-4_1-branch/gcc/ChangeLog
    branches/gcc-4_1-branch/gcc/config/ia64/ia64.h
    branches/gcc-4_1-branch/gcc/config/ia64/unwind-ia64.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444

[Bug debug/24444] [4.1/4.2 regression] invalid register in debug info

[patchapp at dberlin dot org]

------- Comment #17 from patchapp at dberlin dot org  2006-02-21 00:32 -------
Subject: Bug number PR debug/24444

A patch for this bug has been added to the patch tracker.
The mailing list url for the patch is
http://gcc.gnu.org/ml/gcc-patches/2006-02/msg01635.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24444