[LLVMdev] debugging LLVM generated executables???

[Mark Oskin]

I could do that, but before I venture there, if I did that, could I  
have llvm-gcc produce native object files (not LLVM bytecode) that way  
(using my pass)?  thanks, -Mark

On May 7, 2008, at 11:40 AM, Chris Lattner wrote:

> On Wed, 7 May 2008, Mark Oskin wrote:
>> Just re-sending this.  Anyone have any suggestions on how to proceed
>> with debugging LLVM produced executables?  The problem appears to be
>> register-allocated variables.  Global variables and syntax lines do
>> get symbols using the llc / as method I described below.  -Mark
>
> Have you considered adding your pass to llvm-backend.cpp in  
> llvmgcc?  This
> would allow you to use llvm-gcc from the command line, without  
> having to
> invoke individual tools directly.
>
> -Chris
>
>> On May 6, 2008, at 7:36 AM, Mark Oskin wrote:
>>
>>>
>>>> I think you probably need to pass -O0 to llvm-ld.  The link-time
>>>> optimizations are probably killing your debug info.
>>>>
>>> No dice.  Doing it this way makes gdb spew out this:
>>>
>>> warning: Could not find object file "/var/folders/cQ/cQ+L3+RP2RWOpE
>>> +8ZNQdPU+++TI/-Tmp-//ccVljWhn.o" - no debug information available  
>>> for
>>> "defs.h"
>>>
>>> And then no debug symbols are available.
>>>
>>> I also discovered a major down side to the "solution" I found last
>>> night.  While the line number data does get successfully transfered
>>> into gdb, I cannot inspect any variables.  Those appear to have been
>>> lost.
>>>
>>> Any other suggestions out there?
>>>
>>> thanks!
>>>
>>> -mark
>>>
>>>> --Owen
>>>>
>>>> On May 5, 2008, at 8:21 PM, Mark Oskin wrote:
>>>>
>>>>> Hi everyone again,
>>>>>
>>>>> I did discover the following works (see below).  However, does
>>>>> anyone
>>>>> know of the "proper" way with LLVM?
>>>>>
>>>>> llvm-gcc -g -c -emit-llvm helloworld.c
>>>>> opt -load=mypass.dylib -mypass < helloworld.o > helloworld- 
>>>>> mypass.o
>>>>> llc -fast -f -o helloworld.s helloworld-mypass.o
>>>>> as -o helloworld-prime.o
>>>>> gcc -o helloworld helloworld-prime.o
>>>>> gdb helloworld
>>>>>
>>>>> On May 5, 2008, at 4:17 PM, Mark Oskin wrote:
>>>>>
>>>>>> Hi everyone,
>>>>>>
>>>>>> I have a question that seems simple, but has been confounding me
>>>>>> for
>>>>>> several hours.  I'd like to debug a binary produced with LLVM.   
>>>>>> For
>>>>>> the life of me, I can't get any symbols into gdb and llvm-db  
>>>>>> won't
>>>>>> even start the program nor load any useful information about it.
>>>>>> Here's my current strategy (which isn't working):
>>>>>>
>>>>>> llvm-gcc -g -O0 -c -emit-llvm helloworld.c
>>>>>> opt -load=mypass.dylib -mypass < helloworld.o > helloworld- 
>>>>>> mypass.o
>>>>>> llvm-ld -native -o helloworld helloworld-mypass.o
>>>>>> gdb helloworld
>>>>>>
>>>>>> I've tried several variations on the above.
>>>>>>
>>>>>> Any suggestions?
>>>>>>
>>>>>> Note, what is critical about the whole thing is I must run
>>>>>> "mypass" on
>>>>>> the bytecode file.  I'm hoping there's an easy fix, that will  
>>>>>> both
>>>>>> allow me to run my arbitrary pass, and debug a program.
>>>>>>
>>>>>> thanks,
>>>>>>
>>>>>> -Mark
>>>>>> _______________________________________________
>>>>>> LLVM Developers mailing list
>>>>>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>>>>
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>
> -Chris
>
> -- 
> http://nondot.org/sabre/
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