[PATCH] bfd: Fix issues with files in debug_line table with dwarf5.

[Potharla, Rupesh]

[AMD Official Use Only - General]



>-----Original Message-----
>From: Jan Beulich <jbeulich@suse.com>
>Sent: Wednesday, May 25, 2022 11:49 AM
>To: Potharla, Rupesh <Rupesh.Potharla@amd.com>
>Cc: George, Jini Susan <JiniSusan.George@amd.com>; Parasuraman,
>Hariharan <Hariharan.Parasuraman@amd.com>; Natarajan, Kavitha
><Kavitha.Natarajan@amd.com>; Potharla, Rupesh via Binutils
><binutils@sourceware.org>
>Subject: Re: [PATCH] bfd: Fix issues with files in debug_line table with dwarf5.
>
>[CAUTION: External Email]
>
>On 25.05.2022 06:20, Potharla, Rupesh wrote:
>>>> -      /* Skip the first "zero entry", which is the compilation dir/file.  */
>>>> -      if (datai != 0)
>>>> -         if (!callback (table, fe.name, fe.dir, fe.time, fe.size))
>>>> -           return false;
>>>> +      if (!callback (table, fe.name, fe.dir, fe.time, fe.size))
>>>> +        return false;
>>>>      }
>>>
>>> How come this change doesn't add a version check?
>>>
>> Since the function read_formatted_entries is only called for version 5 in the
>file, I thought the version check is not needed. Now I have added the
>condition and updated the patch.
>
>Oh, I'm sorry - I hadn't noticed this aspect. I don't think a version check is
>needed then.
>
>>> To help being certain this is the right way of changing things, can
>>> you please add up to two testcases (readelf and/or objdump), one for
>>> a version < 5 (unless one such already exists and hence it would be
>>> visible there that you don't unduly alter handling of those older versions)
>and one for version 5?
>>>
>>
>> Readelf and objdump are not using dwarf2.c file under bfd directory these
>tools are using dwarf.c under binutils directory.
>
>Argh, yes - too many dwarf*.c in the tree.
>
>>  Currently I am using addr2line to test and validate my code changes
>manually. There are no testcases for addr2line and I did not find any testcases
>for bfd library as well.  Please let me know your suggestions .
>
>Is there a reason speaking against adding an addr2line test? The generic
>framework looks to know of addr2line. (Perhaps ideally the same source
>would be used for both an addr2line test and a readelf or objdump one, as to
>prove that the two forms of Dwarf reading are actually in sync. But I guess
>that's asking for too much.)
>

Regarding test for addr2line, the input address given to addr2line is retrieved from output of nm/objdump tool. The functioning of the addr2line tool depends on the reliability of other tools.

>Jan