[objdump Question] How to sort assembly code by each line number ?

[Taeung Song]

Hi Pedro :)

Thanks for your kind answer!
I didn't consider gdb but if using gdb for my purpose as you said,
it seems like a great idea! :)

Thanks,
Taeung

On 02/21/2017 09:27 PM, Pedro Alves wrote:
> On 02/21/2017 09:53 AM, Nick Clifton wrote:
>> Hi Taeung,
>>
>>> If objdump has the option sorting assembly code according to line numbers,
>>> I want to use the option.
>>
>> Sorry - objdump has no such option.
>>
>>> For example,
>>> I want to sort the below output.
>>> (especially parts of assembly code of line number 34)
>>
>> The problem is that the same line of source code can appear in lots of places
>> in the assembler (for example because of macros, inline functions, templates, etc).
>> Plus compiler optimizations like loop unrolling can replicate the same line
>> of source code multiple times in the assembler output.  So there really is no
>> easy way to produce *meaningful* disassembly sorted by line number.
>>
>>> If there isn't the option for it, I'd manually parse the output from 'objdump -dl'..
>>
>> You can of course write a script to perform this sorting for you, so that you
>> do not have to do it by hand every time.
>
> Might be easier to use GDB for this.  GDB's disassemble command has a
> modifier that sorts by source line instead of address.  For example:
>
>  $ gdb --batch -ex "disassemble /m function" PROGRAM
>
> Funny enough the "/m" modifier is deprecated because
> it wasn't found useful:
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> (gdb) help disassemble
> Disassemble a specified section of memory.
> Default is the function surrounding the pc of the selected frame.
>
> With a /m modifier, source lines are included (if available).
> This view is "source centric": the output is in source line order,
> regardless of any optimization that is present.  Only the main source file
> is displayed, not those of, e.g., any inlined functions.
> This modifier hasn't proved useful in practice and is deprecated
> in favor of /s.
>
> With a /s modifier, source lines are included (if available).
> This differs from /m in two important respects:
> - the output is still in pc address order, and
> - file names and contents for all relevant source files are displayed.
> [....]
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> gdb uses the same library as objdump for the actual instruction
> disassembly, so the output should be similar/familiar.
>
> Thanks,
> Pedro Alves
>