[compiler-rt] r250806 - [ubsan] Fix looksLikeFloatCastOverflowDataV1 heuristic to work if one of the types is unknown.

[Alexey Samsonov via llvm-commits]

Thank you!

On Tue, Oct 20, 2015 at 1:40 AM, Yury Gribov via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

> Author: ygribov
> Date: Tue Oct 20 03:40:52 2015
> New Revision: 250806
>
> URL: http://llvm.org/viewvc/llvm-project?rev=250806&view=rev
> Log:
> [ubsan] Fix looksLikeFloatCastOverflowDataV1 heuristic to work if one of
> the types is unknown.
>
> Differential revision: http://reviews.llvm.org/D13775
>
> Modified:
>     compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc
>
> Modified: compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc
> URL:
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc?rev=250806&r1=250805&r2=250806&view=diff
>
> ==============================================================================
> --- compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc (original)
> +++ compiler-rt/trunk/lib/ubsan/ubsan_handlers.cc Tue Oct 20 03:40:52 2015
> @@ -314,12 +314,14 @@ static bool looksLikeFloatCastOverflowDa
>                    sizeof(FilenameOrTypeDescriptor));
>
>    // Heuristic: For float_cast_overflow, the TypeKind will be either
> TK_Integer
> -  // (0x0) or TK_Float (0x1). Adding both bytes will be 0 or 1 (for BE or
> LE).
> -  // If it were a filename, adding two printable characters will not
> yield such
> -  // a value.
> +  // (0x0), TK_Float (0x1) or TK_Unknown (0xff). If both types are known,
> +  // adding both bytes will be 0 or 1 (for BE or LE). If it were a
> filename,
> +  // adding two printable characters will not yield such a value.
> Otherwise,
> +  // if one of them is 0xff, this is most likely TK_Unknown type
> descriptor.
>    u16 MaybeFromTypeKind =
>        FilenameOrTypeDescriptor[0] + FilenameOrTypeDescriptor[1];
> -  return MaybeFromTypeKind < 2;
> +  return MaybeFromTypeKind < 2 || FilenameOrTypeDescriptor[0] == 0xff ||
> +         FilenameOrTypeDescriptor[1] == 0xff;
>  }
>
>  static void handleFloatCastOverflow(void *DataPtr, ValueHandle From,
>
>
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-- 
Alexey Samsonov
vonosmas at gmail.com
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