[llvm] r229980 - Disallow implicit conversions from None to integer types

[Andrea Di Biagio]

Hi Justin,

Just for your info. After this change I get tons of new warnings
because of ‘llvm::None’ defined but not used [-Wunused-variable].

Example:

In file included from llvm/include/llvm/ADT/ArrayRef.h:13:0,
                 llvm/include/llvm/ADT/APInt.h:19,
                 llvm/include/llvm/ADT/APFloat.h:20,
                 llvm/lib/Support/APFloat.cpp:15:
llvm/include/llvm/ADT/None.h:23:17: warning: ‘llvm::None’ defined but
not used [-Wunused-variable]
 static NoneType None;
                 ^

I am using gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1).

-Andrea

On Fri, Feb 20, 2015 at 7:28 AM, Justin Bogner <mail at justinbogner.com> wrote:
> Author: bogner
> Date: Fri Feb 20 01:28:28 2015
> New Revision: 229980
>
> URL: http://llvm.org/viewvc/llvm-project?rev=229980&view=rev
> Log:
> Disallow implicit conversions from None to integer types
>
> This fixes an error introduced in r228934 where None was converted to
> an int instead of the int being converted to an Optional as intended.
> We make that sort of mistake a compile error by changing NoneType into
> a scoped enum.
>
> Finally, provide a static NoneType called None to avoid forcing all
> users to spell it NoneType::None.
>
> Modified:
>     llvm/trunk/include/llvm/ADT/None.h
>     llvm/trunk/lib/ProfileData/CoverageMapping.cpp
>
> Modified: llvm/trunk/include/llvm/ADT/None.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/None.h?rev=229980&r1=229979&r2=229980&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/ADT/None.h (original)
> +++ llvm/trunk/include/llvm/ADT/None.h Fri Feb 20 01:28:28 2015
> @@ -19,9 +19,8 @@
>  namespace llvm {
>  /// \brief A simple null object to allow implicit construction of Optional<T>
>  /// and similar types without having to spell out the specialization's name.
> -enum NoneType {
> -  None
> -};
> +enum class NoneType { None };
> +static NoneType None;
>  }
>
>  #endif
>
> Modified: llvm/trunk/lib/ProfileData/CoverageMapping.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ProfileData/CoverageMapping.cpp?rev=229980&r1=229979&r2=229980&view=diff
> ==============================================================================
> --- llvm/trunk/lib/ProfileData/CoverageMapping.cpp (original)
> +++ llvm/trunk/lib/ProfileData/CoverageMapping.cpp Fri Feb 20 01:28:28 2015
> @@ -361,7 +361,9 @@ static Optional<unsigned> findMainViewFi
>        IsNotExpandedFile[CR.ExpandedFileID] = false;
>    IsNotExpandedFile &= FilenameEquivalence;
>    int I = IsNotExpandedFile.find_first();
> -  return I != -1 ? I : None;
> +  if (I == -1)
> +    return None;
> +  return I;
>  }
>
>  static Optional<unsigned> findMainViewFileID(const FunctionRecord &Function) {
> @@ -370,7 +372,9 @@ static Optional<unsigned> findMainViewFi
>      if (CR.Kind == CounterMappingRegion::ExpansionRegion)
>        IsNotExpandedFile[CR.ExpandedFileID] = false;
>    int I = IsNotExpandedFile.find_first();
> -  return I != -1 ? I : None;
> +  if (I == -1)
> +    return None;
> +  return I;
>  }
>
>  /// Sort a nested sequence of regions from a single file.
>
>
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