[cfe-commits] r91210 - in /cfe/trunk: lib/Sema/SemaExpr.cpp test/SemaCXX/offsetof.cpp test/SemaCXX/vararg-non-pod.cpp

[Chris Lattner]

On Dec 11, 2009, at 11:25 PM, Douglas Gregor wrote:

> Author: dgregor
> Date: Sat Dec 12 01:25:49 2009
> New Revision: 91210
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=91210&view=rev
> Log:
> Suppress warnings and errors about certain uses of non-POD types (in
> __builtin_offsetof, passing through an ellipsis) when we're in an
> unevaluated context. This is the first part of the fix to PR5761,
> which deals with the simple case of an unevaluated context.

Thanks Doug, I feel bad turning this into an error :).

However, it seems bad to duplicate this switch like this into each place that wants to emit a "runtime error".  Would it make sense for the individual diagnostic producing cases to make a partial diagnostic and pass it into code that either ignores it, emits it, or buffers it?

-Chris


> 
> Modified:
>    cfe/trunk/lib/Sema/SemaExpr.cpp
>    cfe/trunk/test/SemaCXX/offsetof.cpp
>    cfe/trunk/test/SemaCXX/vararg-non-pod.cpp
> 
> Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=91210&r1=91209&r2=91210&view=diff
> 
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaExpr.cpp Sat Dec 12 01:25:49 2009
> @@ -259,15 +259,39 @@
>   DefaultArgumentPromotion(Expr);
> 
>   if (Expr->getType()->isObjCInterfaceType()) {
> -    Diag(Expr->getLocStart(),
> -         diag::err_cannot_pass_objc_interface_to_vararg)
> -      << Expr->getType() << CT;
> -    return true;
> +    switch (ExprEvalContexts.back().Context ) {
> +    case Unevaluated:
> +      // The argument will never be evaluated, so don't complain.
> +      break;
> +
> +    case PotentiallyEvaluated:
> +      Diag(Expr->getLocStart(),
> +           diag::err_cannot_pass_objc_interface_to_vararg)
> +        << Expr->getType() << CT;
> +      return true;
> +
> +    case PotentiallyPotentiallyEvaluated:
> +      // FIXME: queue it!
> +      break;
> +    }
>   }
> 
> -  if (!Expr->getType()->isPODType())
> -    Diag(Expr->getLocStart(), diag::warn_cannot_pass_non_pod_arg_to_vararg)
> -      << Expr->getType() << CT;
> +  if (!Expr->getType()->isPODType()) {
> +    switch (ExprEvalContexts.back().Context ) {
> +    case Unevaluated:
> +      // The argument will never be evaluated, so don't complain.
> +      break;
> +
> +    case PotentiallyEvaluated:
> +      Diag(Expr->getLocStart(), diag::warn_cannot_pass_non_pod_arg_to_vararg)
> +        << Expr->getType() << CT;
> +      break;
> +
> +    case PotentiallyPotentiallyEvaluated:
> +      // FIXME: queue it!
> +      break;
> +    }
> +  }
> 
>   return false;
> }
> @@ -6451,10 +6475,23 @@
>       RecordDecl *RD = RC->getDecl();
>       if (CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
>         if (!CRD->isPOD() && !DidWarnAboutNonPOD) {
> -          ExprError(Diag(BuiltinLoc, diag::warn_offsetof_non_pod_type)
> -            << SourceRange(CompPtr[0].LocStart, OC.LocEnd)
> -            << Res->getType());
> -          DidWarnAboutNonPOD = true;
> +          switch (ExprEvalContexts.back().Context ) {
> +          case Unevaluated:
> +            // The argument will never be evaluated, so don't complain.
> +            break;
> +            
> +          case PotentiallyEvaluated:
> +            ExprError(Diag(BuiltinLoc, diag::warn_offsetof_non_pod_type)
> +                      << SourceRange(CompPtr[0].LocStart, OC.LocEnd)
> +                      << Res->getType());
> +            DidWarnAboutNonPOD = true;
> +            break;
> +            
> +          case PotentiallyPotentiallyEvaluated:
> +            // FIXME: Queue it!
> +            DidWarnAboutNonPOD = true;
> +            break;
> +          }
>         }
>       }
> 
> 
> Modified: cfe/trunk/test/SemaCXX/offsetof.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/offsetof.cpp?rev=91210&r1=91209&r2=91210&view=diff
> 
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/offsetof.cpp (original)
> +++ cfe/trunk/test/SemaCXX/offsetof.cpp Sat Dec 12 01:25:49 2009
> @@ -16,3 +16,5 @@
> struct Base { int x; };
> struct Derived : Base { int y; };
> int o = __builtin_offsetof(Derived, x); // expected-warning{{offset of on non-POD type}}
> +
> +const int o2 = sizeof(__builtin_offsetof(Derived, x));
> 
> Modified: cfe/trunk/test/SemaCXX/vararg-non-pod.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/vararg-non-pod.cpp?rev=91210&r1=91209&r2=91210&view=diff
> 
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/vararg-non-pod.cpp (original)
> +++ cfe/trunk/test/SemaCXX/vararg-non-pod.cpp Sat Dec 12 01:25:49 2009
> @@ -66,3 +66,12 @@
>   E e(10, c); // expected-warning{{cannot pass object of non-POD type 'class C' through variadic constructor; call will abort at runtime}}
>   (void)E(10, c); // expected-warning{{cannot pass object of non-POD type 'class C' through variadic constructor; call will abort at runtime}}
> }
> +
> +// PR5761: unevaluated operands and the non-POD warning
> +class Foo {
> + public:
> +  Foo() {}
> +};
> +
> +int Helper(...);
> +const int size = sizeof(Helper(Foo()));
> 
> 
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