[Dwarf-Discuss] Retrieving variables, function address using dwarf

[Michael Eager]

On 3/10/21 10:38 PM, Archana Deshmukh wrote:
> Thanks Michael for the response. Actually, I have only this much 
> information.
> 
> I need to get information related to
> 
>  ?For global variables , I read the address "55b51afea000" from? ? ?> 
> /proc/<pid>/maps file. I use DW_OP_addr parameter to retrieve?the address.
> 
>  ?55b51afea000?+?DW_OP_addr gives me the address of global variables.
> 
> For function, I read the address "55b51afea000" from? ? ?> 
> /proc/<pid>/maps file.. I use DW_AT_low_pc parameter to retrieve the 
> function starting address
> 
> Now, I need to read the local variables address. As I am not executing 
> the process, I cannot use registers. I need to use DW_OP_call_frame_cfa. 
> I am not able to understand how to retrieve addresses using 
> DW_OP_call_frame_cfa.
> 
> Any pointer or suggestion are most welcome.

Attach to the process using ptrace() and you can get process registers.

> 
> Best Regards,
> Archana
> 
> 
> 
> 
> On Tue, Mar 9, 2021 at 11:07 PM Michael Eager <eager at eagercon.com 
> <mailto:eager at eagercon.com>> wrote:
> 
>     It's difficult to offer advice with such a spare description.
> 
>     You might read the executable and relocate the .debug_info and
>     other debug sections using the process map.? If you have the
>     process image, this probably would not be necessary.
> 
>     On 3/8/21 1:49 AM, Archana Deshmukh via Dwarf-Discuss wrote:
>      > Hello,
>      >
>      > I have a pinatrace.out and process map of a file.
>      > With this input, I need to build a symbol table.
>      >
>      > Best Regards,
>      > Archana Deshmukh
>      >
>      > On Sun, Mar 7, 2021 at 10:29 AM Archana Deshmukh
>      > <desharchana19 at gmail.com <mailto:desharchana19 at gmail.com>
>     <mailto:desharchana19 at gmail.com <mailto:desharchana19 at gmail.com>>>
>     wrote:
>      >
>      >
>      >
>      >? ? ?---------- Forwarded message ---------
>      >? ? ?From: *Michael Eager* <eager at eagercon.com
>     <mailto:eager at eagercon.com> <mailto:eager at eagercon.com
>     <mailto:eager at eagercon.com>>>
>      >? ? ?Date: Sat, Mar 6, 2021 at 10:53 PM
>      >? ? ?Subject: Re: [Dwarf-Discuss] Retrieving variables, function
>     address
>      >? ? ?using dwarf
>      >? ? ?To: Archana Deshmukh <desharchana19 at gmail.com
>     <mailto:desharchana19 at gmail.com>
>      >? ? ?<mailto:desharchana19 at gmail.com
>     <mailto:desharchana19 at gmail.com>>>,
>     <dwarf-discuss at lists.dwarfstd.org
>     <mailto:dwarf-discuss at lists.dwarfstd.org>
>      >? ? ?<mailto:dwarf-discuss at lists.dwarfstd.org
>     <mailto:dwarf-discuss at lists.dwarfstd.org>>>
>      >
>      >
>      >? ? ?On 3/5/21 8:28 PM, Archana Deshmukh via Dwarf-Discuss wrote:
>      >? ? ? > I need to read the address?of local?variable, global variable,
>      >? ? ?function
>      >? ? ? > name?and function?arguments from the process.
>      >? ? ? >
>      >? ? ? > For global variables , I read the address "55b51afea000" from
>      >? ? ? > /proc/<pid>/maps file. I use DW_OP_addr parameter to
>     retrieve?the
>      >? ? ?address.
>      >? ? ? > 55b51afea000?+?DW_OP_addr gives me the address of global
>     variable.
>      >? ? ? >
>      >? ? ? > I need to read the stack?segment, heap. Is there any way
>     to read
>      >? ? ? > segments? DW_AT_segment parameter seems to be for 16 bit.
>      >? ? ? >
>      >? ? ? > I need to read the following process map using dwarf.
>      >? ? ? >
>      >? ? ? > Any suggestion, pointers are welcome.
>      >? ? ? >
>      >? ? ? > 55b51afea000-55b51afeb000 r-xp 00000000 fd:00 5902563
>      >
>      >? ? ?Can you explain what you are trying to do?
>      >
>      >? ? ?Usually a DWARF consumer (a debugger) does not need to read the
>      >? ? ?process memory map.? All of the information you mention is in
>      >? ? ?the DWARF data.? You may need to relocate addresses in the DWARF
>      >? ? ?debug data.
>      >
>      >? ? ?DWARF does not contain information about the process memory
>      >? ? ?layout, such as the location of the heap or the start of the
>      >? ? ?stack.
>      >
>      >? ? ?--
>      >? ? ?Michael Eager
>      >
>      >
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> 
>     -- 
>     Michael Eager
> 

-- 
Michael Eager