llvm dev - May 2015 - [LLVMdev] Modifying debug information through llvm pass

Hi All,

I want to change debug information of an llvm instruction so that the 
modified debug info is subsequently passed to executable binary. So if I 
use "addr2line" utility on the binary, it will return my modified
debug
information.

I've tried to change by using the following code snippet:

    MDNode *N = Inst->getMetadata("dbg");
    DebugLoc Loc = DebugLoc::get(newLine, newCol, N);
    Inst->setDebugLoc(Loc);

I read the DebugLoc back by using

    const DebugLoc D = Inst->getDebugLoc();
    unsigned Line = D.getLine();
    outs() << Line <<"\n";

But I can't set the debug info correctly. How can I change the debug 
info correctly through llvm pass?

Thanks
Riyad
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20150512/b5fd2783/attachment.html>

> On May 12, 2015, at 7:59 PM, Riyad Parvez <riyad.parvez at
uwaterloo.ca> wrote:
> 
> Hi All,
> 
> I want to change debug information of an llvm instruction so that the
modified debug info is subsequently passed to executable binary. So if I use
"addr2line" utility on the binary, it will return my modified debug
information.
> 
> I've tried to change by using the following code snippet:
> 
> MDNode *N = Inst->getMetadata("dbg");
> DebugLoc Loc = DebugLoc::get(newLine, newCol, N);
Your use of N looks sketchy here. The third argument of DebugLoc::get() is
supposed to be the scope of the location, so you probably want
  Inst->getDebugLoc().getScope()
there?

-- adrian
  
> Inst->getDebugLoc();
> Inst->setDebugLoc(Loc);
> I read the DebugLoc back by using
> const DebugLoc D = Inst->getDebugLoc();
> unsigned Line = D.getLine(); 
> outs() << Line <<"\n"; 
> But I can't set the debug info correctly. How can I change the debug
info correctly through llvm pass?
> 
> Thanks
> Riyad
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

On 05/15/2015 05:21 PM, Adrian Prantl wrote:
>> On May 12, 2015, at 7:59 PM, Riyad Parvez <riyad.parvez at
uwaterloo.ca> wrote:
>>
>> Hi All,
>>
>> I want to change debug information of an llvm instruction so that the
modified debug info is subsequently passed to executable binary. So if I use
"addr2line" utility on the binary, it will return my modified debug
information.
>>
>> I've tried to change by using the following code snippet:
>>
>> MDNode *N = Inst->getMetadata("dbg");
>> DebugLoc Loc = DebugLoc::get(newLine, newCol, N);
> Your use of N looks sketchy here. The third argument of DebugLoc::get() is
supposed to be the scope of the location, so you probably want
>    Inst->getDebugLoc().getScope()
> there?
Thanks for pointing that out. It worked.

Thanks
Riyad
> -- adrian
>    
>> Inst->getDebugLoc();
>> Inst->setDebugLoc(Loc);
>> I read the DebugLoc back by using
>> const DebugLoc D = Inst->getDebugLoc();
>> unsigned Line = D.getLine();
>> outs() << Line <<"\n";
>> But I can't set the debug info correctly. How can I change the
debug info correctly through llvm pass?
>>
>> Thanks
>> Riyad
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev