llvm dev - May 2013 - [LLVMdev] Attributes & CloneFunctionInto

Hi,

I am again struggling to find my way around the Attribute classes.
What I want to do is clone a function into a declaration where some 
parameters may have a different alignment.
CloneFunctionInto in debug mode hits an assertion which is marked with a 
FIXME (Attributes.cpp:673).
I would be totally fine with any kind of workaround, e.g. removing all 
attributes from the target declaration, then cloning, and then setting 
the correct attributes.
However, I can't find a way to modify an existing alignment *in any way* 
without hitting an assertion (the other one being line 727 for 
removeAttributes). I've also tried using addAttributes() and 
setAttributes() to set the alignment to 0, but this seems to be ignored...

Any help on this? :)

Thanks,
Ralf

On 5/15/13 10:27 AM, Ralf Karrenberg wrote:
> Hi,
>
> I am again struggling to find my way around the Attribute classes.
> What I want to do is clone a function into a declaration where some 
> parameters may have a different alignment.
> CloneFunctionInto in debug mode hits an assertion which is marked with 
> a FIXME (Attributes.cpp:673).
> I would be totally fine with any kind of workaround, e.g. removing all 
> attributes from the target declaration, then cloning, and then setting 
> the correct attributes.
> However, I can't find a way to modify an existing alignment *in any 
> way* without hitting an assertion (the other one being line 727 for 
> removeAttributes). I've also tried using addAttributes() and 
> setAttributes() to set the alignment to 0, but this seems to be 
> ignored...
SAFECode clones a function to change the alignment of byval arguments.  
You can look at the code at 
http://llvm.org/viewvc/llvm-project/safecode/branches/release_32/lib/BaggyBoundsChecks/BaggyBoundsChecks.cpp?revision=177641&view=markup.

Note that the code works with LLVM 3.2.

-- John T.
>
> Any help on this? :)
>
> Thanks,
> Ralf
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

Hi John,

thanks for the pointer. However, I'd rather avoid rolling a custom 
implementation. After all, it's not like I want to do something 
drastically different...
I had sorted out the problem for 3.2 as well as a previous version of 
3.3 trunk, but the API changed about a hundred times. Now as it 
apparently has stabilized, I moved to a the 3.3 release branch just to 
find that even my previous workarounds don't work anymore.

I can't understand why the API of llvm::Function does not simply provide 
two functions
- setAttribute(unsigned paramIdx, AttributeKind A) and
- removeAttribute(unsigned paramIdx, AttributeKind A).

Cheers,
Ralf

On 5/15/13 5:39 PM, John Criswell wrote:
> On 5/15/13 10:27 AM, Ralf Karrenberg wrote:
>> Hi,
>>
>> I am again struggling to find my way around the Attribute classes.
>> What I want to do is clone a function into a declaration where some
>> parameters may have a different alignment.
>> CloneFunctionInto in debug mode hits an assertion which is marked with
>> a FIXME (Attributes.cpp:673).
>> I would be totally fine with any kind of workaround, e.g. removing all
>> attributes from the target declaration, then cloning, and then setting
>> the correct attributes.
>> However, I can't find a way to modify an existing alignment *in any
>> way* without hitting an assertion (the other one being line 727 for
>> removeAttributes). I've also tried using addAttributes() and
>> setAttributes() to set the alignment to 0, but this seems to be
>> ignored...
>
> SAFECode clones a function to change the alignment of byval arguments.
> You can look at the code at
>
http://llvm.org/viewvc/llvm-project/safecode/branches/release_32/lib/BaggyBoundsChecks/BaggyBoundsChecks.cpp?revision=177641&view=markup.
>
>
> Note that the code works with LLVM 3.2.
>
> -- John T.
>
>>
>> Any help on this? :)
>>
>> Thanks,
>> Ralf
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>