[cfe-commits] [PATCH] Type safety attributes (was: Compile-time MPI_Datatype checking)

[Dmitri Gribenko]

Hi Hal,

Thank you for the review.  Comments inline.

Updated version of the patch attached.  Changes include addressing the
review comments and proper handling of 128-bit integer constants in
attribute arguments and type tags (ensures we don't crash in these
cases).

On Thu, May 24, 2012 at 5:27 AM, Hal Finkel <hfinkel at anl.gov> wrote:
> layout_compatible - The documentation on this needs to be expanded.
> I recommend an example or two (at least).

Added an example.  Is that enough or more explanations are needed?

> Do we need a new has_feature check so that we can properly guard the
> new attributes in public headers?

__has_attribute already works with these attributes.

> Are C++ objects that are implicitly convertible to pointers of the
> correct type handled correctly [this is not obvious to me from reading
> the patch, but I'm not an expert here]?

Classes with conversion operators, like this:
class OperatorIntStar
{
public:
  operator int*();
};
These classes are supported.  I've added a test for that to make sure
we don't regress.

>> +  bool IsMPI = ArgumentKind->isStr("mpi");
>> +
>> +  if (SpecifiedType->isVoidType()) {
>> +    // Type tag with matching void type requires a null pointer.
>> +    if (!ArgumentExpr->isNullPointerConstant(Context,
>> +
>> Expr::NPC_ValueDependentIsNotNull)) {
>> +      Diag(ArgumentExpr->getExprLoc(),
>> +           IsMPI ? diag::warn_mpi_datatype_null_but_buffer_not_null
>> +                 : diag::warn_type_safety_null_pointer_required)
>> +          << ArgumentExpr->getSourceRange()
>> +          << TypeTagExpr->getSourceRange();
>> +    }
>> +    return;
>> +  }
>
> Can we generalize this as well? Maybe we should call this
> void_must_be_null, and make it like layout_compatible (an optional
> parameter)? [As far as I can tell, this is the only MPI-specific logic
> left, is there anything else?]

Done.
Yes, that was the only piece of MPI-specific logic.

Dmitri

-- 
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
(j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/
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