llvm dev - Apr 2010 - [LLVMdev] Creating a Return Instruction.

Hi all,

   I have to create a return instruction in a function. The function is of
type -- void * func (void *) . So i have to create a return instruction for
the function that should return a void pointer. But actually the function
will not return anything useful . it will be something like --  return void
* null.  The problem i am facing is to create a return instruction the
Create function expects a pointer to a value and i am not able to do that.
How do i create such a return instruction.

Thanks,
Rohith.
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On 17 April 2010 23:12, Rohith Goparaju <rgoparaj at umail.iu.edu>
wrote:
> But actually the function will not return anything useful.
>
Then I assume it should return an undef:
http://llvm.org/docs/LangRef.html#undefvalues

Rohith Goparaju wrote:
> Hi all,
>
>     I have to create a return instruction in a function. The function is
> of type -- void * func (void *) . So i have to create a return
> instruction for the function that should return a void pointer. But
> actually the function will not return anything useful . it will be
> something like --  return void * null.  The problem i am facing is to
> create a return instruction the Create function expects a pointer to a
> value and i am not able to do that. How do i create such a return
> instruction.
'void *' is not a valid LLVM type. Did you mean 'i8 *'?

   LLVMContext C;
   const Type *Ty = Type::getInt8Ty(C)->getPointerTo();

'ret i8* null':

   Builder.CreateRet(Constant::getNullValue(Ty));

'ret i8* undef':

   Builder.CreateRet(UndefValue::get(Ty));

Nick