[PATCH] D49511: [Sema/Attribute] Check for noderef attribute

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added inline comments.


================
Comment at: lib/Sema/SemaExpr.cpp:14249
+
+    if (Sema::TypeHasNoDeref(Inner))
+      DeclRef = E;
----------------
leonardchan wrote:
> aaron.ballman wrote:
> > The sugar was stripped off at the pointer level, but not at the pointee level. e.g.,
> > ```
> > typedef int (bobble);
> > typedef bobble * (frobble);
> > typedef frobble * yobble;
> > 
> > yobble gobble;
> > ```
> > I think you can handle this within `TypeHasNoDeref()` and that should fix up all the callers.
> So `TypeHasNoDeref()` checks for the attribute on the base type already and is called after the pointer is stripped off. Attempting to desugar via `getDesugaredType()` here also removes the `address_space` attribute from the type I'm checking.
> 
> Do you know another method that essentially "expands" the typedefs without stripping the qualifiers? Otherwise I think I do need do the desugaring at the pointer level. Alternatively I could also change this method such that it accepts pointers instead of pointees since it appears I already call `getDesugaredType()` for almost every pointer who's pointee I'm passing to `TypeHasNoDeref()`.
> 
> Also I tested with your example and the warning still seems to be thrown appropriately. 
I think you have to do the desugaring manually in a loop with `getSingleStepDesugaredType()` so that you don't strip off attributed type information along with the rest of the type sugar.

> Also I tested with your example and the warning still seems to be thrown appropriately.

The example may depend on where you put the attribute (inside the parens vs outside the parens, for instance); it was an off-the-cuff example, so it may need some tweaking.


Repository:
  rC Clang

https://reviews.llvm.org/D49511