[Bug debug/54970] New: Missing DW_OP_GNU_implicit_pointer in debuginfo

[Bug debug/54970] New: Missing DW_OP_GNU_implicit_pointer in debuginfo

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54970

             Bug #: 54970
           Summary: Missing DW_OP_GNU_implicit_pointer in debuginfo
    Classification: Unclassified
           Product: gcc
           Version: 4.7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: jakub@gcc.gnu.org
        ReportedBy: jakub@gcc.gnu.org
                CC: aoliva@gcc.gnu.org


/* { dg-do run } */
/* { dg-options "-g" } */

#include "../nop.h"

int
main ()
{
  int a[] = { 1, 2, 3 };        /* { dg-final { gdb-test 12 "a\[1\]" "2" } } */
  int *p = a + 2;               /* { dg-final { gdb-test 12 "a\[2\]" "3" } } */
  int *q = a + 1;               /* { dg-final { gdb-test 12 "*p" "3" } } */
  asm volatile ("NOP");         /* { dg-final { gdb-test 12 "*q" "2" } } */
  *p += 10;                     /* { dg-final { gdb-test 16 "a\[1\]" "2" } } */
                                /* { dg-final { gdb-test 16 "a\[2\]" "13" } }
*/
                                /* { dg-final { gdb-test 16 "*p" "13" } } */
  asm volatile ("NOP");         /* { dg-final { gdb-test 16 "*q" "2" } } */
  *q += 10;                     /* { dg-final { gdb-test 20 "a\[1\]" "12" } }
*/
                                /* { dg-final { gdb-test 20 "a\[2\]" "13" } }
*/
                                /* { dg-final { gdb-test 20 "*p" "13" } } */
  asm volatile ("NOP");         /* { dg-final { gdb-test 20 "*q" "12" } } */
  return 0;
}

fails, apparently because we have # DEBUG p => &MEM[(void *)&a + 8B]
and we fail to expand that as (plus (debug_implicit_ptr a) (const_int 8)).
The reason for that is that we don't want (mem (debug_implicit_ptr x)) to
appear
in debug insns, that confuses aliasing.  When expanding &a, we expand it as
DEBUG_IMPLICIT_PTR, but when returning to MEM, we return NULL, as that is not
appropriate thing to construct.

[Bug debug/54970] Missing DW_OP_GNU_implicit_pointer in debuginfo

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54970

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2012-10-18
   Target Milestone|---                         |4.8.0
     Ever Confirmed|0                           |1

[Bug debug/54970] Missing DW_OP_GNU_implicit_pointer in debuginfo

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54970

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-10-18 08:55:02 UTC ---
Created attachment 28478
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28478
gcc48-pr54970.patch

Untested fix.

[Bug debug/54970] Missing DW_OP_GNU_implicit_pointer in debuginfo

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54970

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #28478|0                           |1
        is obsolete|                            |

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-10-18 09:26:54 UTC ---
Created attachment 28479
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28479
gcc48-pr54970.patch

The testcase still fails with -m32 -Os, the problem is that DECL_DEBUG_EXPR
isn't created for the replacements in that case.  This patch adds needed
tree-sra.c and var-tracking.c/dwarf2out.c changes to handle MEM_REFs with
ADDR_EXPR in it too.

[Bug debug/54970] Missing DW_OP_GNU_implicit_pointer in debuginfo

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54970

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-10-26 19:19:30 UTC ---
Author: jakub
Date: Fri Oct 26 19:19:25 2012
New Revision: 192860

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=192860
Log:
    PR debug/54970
    * cfgexpand.c (expand_debug_expr): Expand &MEM_REF[&var, n]
    as DEBUG_IMPLICIT_PTR + n if &var expands to DEBUG_IMPLICIT_PTR.
    * tree-sra.c (create_access_replacement): Allow also MEM_REFs
    with ADDR_EXPR first operand in DECL_DEBUG_EXPR expressions.
    * var-tracking.c (track_expr_p): Handle MEM_REFs in DECL_DEBUG_EXPR
    expressions.
    * dwarf2out.c (add_var_loc_to_decl): Likewise.

    PR debug/54971
    * gcc.dg/guality/pr54970.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/guality/pr54970.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cfgexpand.c
    trunk/gcc/dwarf2out.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-sra.c
    trunk/gcc/var-tracking.c

[Bug debug/54970] Missing DW_OP_GNU_implicit_pointer in debuginfo

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54970

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-11-05 14:36:52 UTC ---
Author: jakub
Date: Mon Nov  5 14:36:47 2012
New Revision: 193162

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=193162
Log:
    PR debug/54970
    PR debug/54971
    * gcc.dg/guality/pr54970.c: Use NOP instead of "NOP" in inline-asm.

Modified:
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/guality/pr54970.c

[Bug debug/54970] Missing DW_OP_GNU_implicit_pointer in debuginfo

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54970

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-12-04 13:16:05 UTC ---
Fixed.

[Bug debug/54970] Missing DW_OP_GNU_implicit_pointer in debuginfo

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54970

Steven Bosscher <steven at gcc dot gnu.org> changed:

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

--- Comment #6 from Steven Bosscher <steven at gcc dot gnu.org> 2013-03-12 17:09:14 UTC ---
This test case fails on powerpc64 with fc18.
The *p and *q stores are optimized away.

[Bug debug/54970] Missing DW_OP_GNU_implicit_pointer in debuginfo

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54970

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-03-12 17:50:49 UTC ---
The stores are of course optimized away, everywhere, that is the point of the
testcase.
The problems that cause the debug info to be insufficient on some targets are
tracked e.g. in http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54971#c13
There is no point to keep this PR open for that.

[Bug debug/54970] Missing DW_OP_GNU_implicit_pointer in debuginfo

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54970

Steven Bosscher <steven at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |steven at gcc dot gnu.org

--- Comment #8 from Steven Bosscher <steven at gcc dot gnu.org> 2013-03-12 18:55:19 UTC ---
(In reply to comment #7)
> The stores are of course optimized away, everywhere, that is the point
> of the testcase.

I am talking about the debug_stmts for the stores, sorry if that was not
clear.  On x86_64 the test case passes, but on powerpc64 esra does something
it doesn't do on x86_64 and it makes the test case fail.  Is there a known
bug for that already, also?

This is 176 FAILs on powerpc64.  If it's "supposed to not work" there, then
the test case should be XFAIL'ed there.