[LLVMdev] Inserting dead code in IR byte code

[teja tamboli]

Did you get a chance to take a look at my response Duncan?

Thanks,
Teja

On Mon, Nov 19, 2012 at 9:44 AM, teja tamboli <tamboli.teja at gmail.com>wrote:

> Hi Duncan,
>
> I mean both. In order to generate random code, I have to add function
> definitions and also for robustness I have to call these functions from
> already existing functions. So, have to add calling type of instructions
> also in the existing function.
> In future I also have to change instructions for simple substitution
> meaning
>
> 'add a, b' can be done using  'sub a, 0' and followed by 'add a, b' or
> something like that. So, have to modify / add instructions in the existing
> code.
>
> I am not much aware of LLVM IR Linker (llvm-ld). I know that it takes
> multiple bitcode files and then link them together to generate one bitcode
> file. Is it possible to add functions and instructions using this tool ?
>
>
> Thanks,
> Teja
>
>
>
>
> On Mon, Nov 19, 2012 at 12:20 AM, Duncan Sands <baldrick at free.fr> wrote:
>
>> Hi Teja,
>>
>>
>>  I am working on my Master's project in security and for this I need to do
>>> following things :
>>>
>>> 1. I have a IR bytecode of the main program. I want to insert dead code
>>> from
>>> other source files (e.g. cygwin files or the Linux files) in main
>>> program's IR
>>> byte code.
>>>
>>
>> do you mean adding additional functions?  Or do you mean adding extra
>> instructions to existing functions?  In the first case why not use the
>> LLVM IR linker (llvm-link) to add in the extra bitcode?
>>
>> Ciao, Duncan.
>>
>>
>>  2. In order to insert code, I can try following two ways :
>>>     (i) I have observed that these IR bytecode files are just like a
>>> text file
>>> and they have fixed format. Using file operations, we can modify IR byte
>>> code of
>>> the first file by inserting the IR byte code from other files.
>>>     (ii) Second approach is to use LLC Tool to generate c++ code of
>>> second IR
>>> byte code. Then use generated c++ code and insert into the first IR byte
>>> code.
>>> Write the optimizer pass on first IR byte code and add the instructions
>>> from
>>> generated c++ code. Get the modified IR bytecode of the first program.
>>>
>>> Which approach is better and are there any other ways which I can use?
>>>
>>
>>
>>
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>>
>
>
>
> --
> Regards,
> Teja
>



-- 
Regards,
Teja
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