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From: "vries at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>
To: dwz@sourceware.org
Subject: [Bug default/27449] dwz: 1: Unknown DWARF DW_OP_0
Date: Tue, 02 Mar 2021 15:45:04 +0000	[thread overview]
Message-ID: <bug-27449-11298-w50jlnoJvJ@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-27449-11298@http.sourceware.org/bugzilla/>

https://sourceware.org/bugzilla/show_bug.cgi?id=27449

Tom de Vries <vries at gcc dot gnu.org> changed:

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

--- Comment #4 from Tom de Vries <vries at gcc dot gnu.org> ---
(In reply to Mark Wielaard from comment #2)
>     0012e37f v000000000000003 v000000000000006 location view pair
> 
>     0012e381 v000000000000003 v000000000000006 views at 0012e37f for:
>              00000000001b23a0 00000000001b23a0 (DW_OP_implicit_value 2 byte
> block: 0 0 )
>     0012e397 v0000000000011a0 v00000000000001b views at 0012e381 for:
>              0000000000000000 0604000000000000 (DW_OP_div; (Unknown location
> op 0x0))
>     00130749 v000000000000000 v000000000000000 views at 0012e384 for:
>              00000000001b2ba8 00000000001b2ba8 (DW_OP_lit2;
> DW_OP_stack_value) (start == end)
>     0013075d <End of list>

And using hex:
...
  0x0012e370 00000000 00000000 00000000 00000003
  0x0012e380 06a0231b 00000000 00a0231b 00000000
  0x0012e390 0004009e 02000000 00000000 00000000
  0x0012e3a0 00000000 000406a0 231b0000 000000a0
  0x0012e3b0 231b0000 00000002 00329f00 00000000
  0x0012e3c0 00000000 00000000 00000004 06a0231b
  0x0012e3d0 00000000 00a0231b 00000000 000600f2
...

So let's pick that apart. 

We have two addresses
...
  0x0012e381 a0231b 00000000 00a0231b 00000000
  0x0012e390 00
...
which given the .text dump look plausible.

So this is the length of the dwarf description:
...
  0x0012e391 0400
...

which is:
...
  0x0012e393 9e 020000
...
The 0x 9e is DW_OP_implicit_value. 2 is the length of the dwarf expression,
which is "0x0000".  Still plausible.

The next two addresses (0000000000000000 0604000000000000) make no sense. The
following length of dwarf description of 0x23a0 also not.

-- 
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  parent reply	other threads:[~2021-03-02 15:45 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-21 11:43 [Bug default/27449] New: " doko at debian dot org
2021-02-21 11:43 ` [Bug default/27449] " doko at debian dot org
2021-02-21 11:44 ` doko at debian dot org
2021-02-21 17:14 ` mark at klomp dot org
2021-02-26 20:12 ` mark at klomp dot org
2021-03-02 15:45 ` vries at gcc dot gnu.org [this message]
2021-03-02 15:46 ` vries at gcc dot gnu.org
2021-03-03 15:22 ` mark at klomp dot org
2021-03-04  8:12 ` doko at debian dot org
2021-03-04  9:36 ` mliska at suse dot cz
2021-03-04 10:05 ` mliska at suse dot cz
2021-03-04 10:11 ` mliska at suse dot cz
2021-03-04 14:43 ` mark at klomp dot org
2021-03-04 15:05 ` mark at klomp dot org

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