llvm dev - Apr 2013 - [LLVMdev] Adding custom pragma's for generating particular LLVM IR

Hi ML readers,

I would first apology if this was already addressed on this ML, but I 
didn't find information on this topic.

I would like to add custom pragma's that generate particular LLVM IR. 
Here is an example:


int a, b;

/* ... */

#pragma mypragma shared(a, b)
{
     a = b;
     b++;
}


would result in this (pseudo) LLVM IR:

%1 alloca i32
%2 alloca i32

...

call void @start_callback ()
%3 call i32 @check_callback ( i32 %1 )
%4 call i32 @check_callback ( i32 %2 )
...
call void @end_callback ()

...

Note: All *_callback functions are implemented in a third party library.

I guess that is it quite close to what was implemented for the OpenMP 
support, but I need something simpler.

Basically, how can I
- Add a pragma that identifies a block (i.e. scope) of code ?
- Add an action that flag some variables as __shared__ in the annotated 
block ?
- Generate LLVM IR that add specific call-backs at the start and end of 
the block and on shared variables ?

I hope my explanation is sufficiently clear. Feel free to ask questions 
if it's not.

Best regards,
Julien.

Hi Julien, as this would all presumably be done in the clang front-end I suggest
you ask on the clang mailing list.

Ciao, Duncan.

On 20/04/13 08:43, Julien Peeters wrote:
> Hi ML readers,
>
> I would first apology if this was already addressed on this ML, but I
didn't
> find information on this topic.
>
> I would like to add custom pragma's that generate particular LLVM IR.
Here is an
> example:
>
>
> int a, b;
>
> /* ... */
>
> #pragma mypragma shared(a, b)
> {
>      a = b;
>      b++;
> }
>
>
> would result in this (pseudo) LLVM IR:
>
> %1 alloca i32
> %2 alloca i32
>
> ...
>
> call void @start_callback ()
> %3 call i32 @check_callback ( i32 %1 )
> %4 call i32 @check_callback ( i32 %2 )
> ...
> call void @end_callback ()
>
> ...
>
> Note: All *_callback functions are implemented in a third party library.
>
> I guess that is it quite close to what was implemented for the OpenMP
support,
> but I need something simpler.
>
> Basically, how can I
> - Add a pragma that identifies a block (i.e. scope) of code ?
> - Add an action that flag some variables as __shared__ in the annotated
block ?
> - Generate LLVM IR that add specific call-backs at the start and end of the
> block and on shared variables ?
>
> I hope my explanation is sufficiently clear. Feel free to ask questions if
it's
> not.
>
> Best regards,
> Julien.
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev