[cfe-commits] r134483 - in /cfe/trunk: lib/Sema/TreeTransform.h test/CodeGenCXX/variadic-templates.cpp

[Douglas Gregor]

On Jul 6, 2011, at 12:30 AM, John McCall wrote:

> Author: rjmccall
> Date: Wed Jul  6 02:30:07 2011
> New Revision: 134483
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=134483&view=rev
> Log:
> When tree-transforming an expression sequence, always flag expanded
> variadic argument pack expansions as having changed, rather than doing
> it for each changed expansion, which leaves out zero-argument packs
> with catastrophic consequences.
> 
> Fixes PR10260.
> 
> 
> Modified:
>    cfe/trunk/lib/Sema/TreeTransform.h
>    cfe/trunk/test/CodeGenCXX/variadic-templates.cpp
> 
> Modified: cfe/trunk/lib/Sema/TreeTransform.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/TreeTransform.h?rev=134483&r1=134482&r2=134483&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/TreeTransform.h (original)
> +++ cfe/trunk/lib/Sema/TreeTransform.h Wed Jul  6 02:30:07 2011
> @@ -1547,9 +1547,9 @@
>   /// By default, performs semantic analysis to build the new expression.
>   /// Subclasses may override this routine to provide different behavior.
>   ExprResult RebuildInitList(SourceLocation LBraceLoc,
> -                                   MultiExprArg Inits,
> -                                   SourceLocation RBraceLoc,
> -                                   QualType ResultTy) {
> +                             MultiExprArg Inits,
> +                             SourceLocation RBraceLoc,
> +                             QualType ResultTy) {
>     ExprResult Result
>       = SemaRef.ActOnInitList(LBraceLoc, move(Inits), RBraceLoc);
>     if (Result.isInvalid() || ResultTy->isDependentType())
> @@ -2476,6 +2476,10 @@
>         Outputs.push_back(Out.get());
>         continue;
>       }
> +
> +      // Record right away that the argument was changed.  This needs
> +      // to happen even if the array expands to nothing.
> +      if (ArgChanged) *ArgChanged = true;
> 
>       // The transform has determined that we should perform an elementwise
>       // expansion of the pattern. Do so.
> @@ -2492,8 +2496,6 @@
>             return true;
>         }
> 
> -        if (ArgChanged)
> -          *ArgChanged = true;  
>         Outputs.push_back(Out.get());
>       }

Ah hah… nice catch!

	- Doug