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[Bug rtl-optimization/55346] var-tracking generates incomplete/inaccurate debug info
- From: "eager at eagercon dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 15 Nov 2012 22:36:58 +0000
- Subject: [Bug rtl-optimization/55346] var-tracking generates incomplete/inaccurate debug info
- Auto-submitted: auto-generated
- References: <bug-55346-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55346
--- Comment #3 from Michael Eager <eager at eagercon dot com> 2012-11-15 22:36:58 UTC ---
Top of tree as of Oct 20, 2012. I'll update and verify.
On 11/15/2012 01:42 PM, jakub at gcc dot gnu.org wrote:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55346
>
> Jakub Jelinek <jakub at gcc dot gnu.org> changed:
>
> What |Removed |Added
> ----------------------------------------------------------------------------
> CC| |jakub at gcc dot gnu.org
>
> --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-11-15 21:42:34 UTC ---
> Which gcc version exactly (svn rev or date) you were using?
> I can't reproduce this on x86_64-linux with current trunk and -g -O2.
> <2><68>: Abbrev Number: 4 (DW_TAG_variable)
> <69> DW_AT_name : (indirect string, offset: 0x74): argno
> <6d> DW_AT_decl_file : 1
> <6e> DW_AT_decl_line : 4
> <6f> DW_AT_type : <0x124>
> <73> DW_AT_location : 0x98(location list)
> ...
> 00000098 0000000000400420 0000000000400437 (DW_OP_lit1; DW_OP_stack_value)
> 00000098 0000000000400437 0000000000400483 (DW_OP_reg3 (rbx))
> 00000098 0000000000400483 0000000000400488 (DW_OP_breg3 (rbx): -1;
> DW_OP_stack_value)
> 00000098 0000000000400488 0000000000400491 (DW_OP_reg3 (rbx))
> 00000098 000000000040049f 00000000004004cc (DW_OP_reg3 (rbx))
> 00000098 <End of list>
>
> The only gap in there is in between 491 and 49f, and that is the epilogue:
> 400491: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
> 400498: 5b pop %rbx
> 400499: 5d pop %rbp
> 40049a: 31 c0 xor %eax,%eax
> 40049c: 41 5c pop %r12
> 40049e: c3 retq
> 40049f: 90 nop
>
> I can reproduce it with r192900 though, so I bet this is a dup of PR54693
> (which after all was your testcase).
>