[cfe-commits] r149359 - in /cfe/trunk: lib/Sema/SemaChecking.cpp test/Sema/conversion-64-32.c

[Eli Friedman]

On Mon, Jan 30, 2012 at 9:37 PM, Ted Kremenek <kremenek at apple.com> wrote:
> Author: kremenek
> Date: Mon Jan 30 23:37:48 2012
> New Revision: 149359
>
> URL: http://llvm.org/viewvc/llvm-project?rev=149359&view=rev
> Log:
> Don't warn about -Wshorten-64-to-32 in unreachable code.  Fixes <rdar://problem/10759934>.  Apparently this is a common idiom in Linux (among other places).
>
> Modified:
>    cfe/trunk/lib/Sema/SemaChecking.cpp
>    cfe/trunk/test/Sema/conversion-64-32.c
>
> Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=149359&r1=149358&r2=149359&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaChecking.cpp Mon Jan 30 23:37:48 2012
> @@ -3693,15 +3693,24 @@
>
>  /// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
>  static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T,
> -                            SourceLocation CContext, unsigned diag) {
> +                            SourceLocation CContext, unsigned diag,
> +                            bool pruneControlFlow = false) {
> +  if (pruneControlFlow) {
> +    S.DiagRuntimeBehavior(E->getExprLoc(), E,
> +                          S.PDiag(diag)
> +                            << SourceType << T << E->getSourceRange()
> +                            << SourceRange(CContext));
> +    return;
> +  }
>   S.Diag(E->getExprLoc(), diag)
>     << SourceType << T << E->getSourceRange() << SourceRange(CContext);
>  }
>
>  /// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
>  static void DiagnoseImpCast(Sema &S, Expr *E, QualType T,
> -                            SourceLocation CContext, unsigned diag) {
> -  DiagnoseImpCast(S, E, E->getType(), T, CContext, diag);
> +                            SourceLocation CContext, unsigned diag,
> +                            bool pruneControlFlow = false) {
> +  DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow);
>  }
>
>  /// Diagnose an implicit cast from a literal expression. Does not warn when the
> @@ -3907,7 +3916,8 @@
>       return;
>
>     if (SourceRange.Width == 64 && TargetRange.Width == 32)
> -      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32);
> +      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32,
> +                             /* pruneControlFlow */ true);
>     return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
>   }

Why is -Wshorten-64-to-32 special here?  Why not suppress all
-Wconversion warnings in unreachable code?

-Eli