Fix enum BitcodeError to not define 0.

[kschimpf]

Summary

std::error_code's assume it isn't an error if the error code is zero.
Fix enum BitcodeError to not define a zero-valued error code.

[kschimpf]

While working on PNaCl, I found out that the error code passed to std::error_code must not be zero. If it is zero, the boolean check assumes that an error did not occur. This CL is to fix the corresponding problem in LLVM.

[kschimpf]

Adding llvm-commits

[• rafael]

Please git-clang-format the patch. OK with that.

[• rafael]

Any reason why this has not been committed yet?

[jvoung]

I think it dropped off Karl's radar. He's on vacation right now, but I could help clang-format/commit it for him today.

[• rafael]

Thanks!

llvm/trunk/include/llvm/Bitcode/ReaderWriter.h

inline bool SkipBitcodeWrapperHeader(const unsigned char *&BufPtr,
     if (VerifyBufferSize && Offset+Size > unsigned(BufEnd-BufPtr))
       return true;
     BufPtr += Offset;
     BufEnd = BufPtr+Size;
     return false;
   }
 
   const std::error_category &BitcodeErrorCategory();
-  enum class BitcodeError { InvalidBitcodeSignature, CorruptedBitcode };
+  enum class BitcodeError { InvalidBitcodeSignature = 1, CorruptedBitcode };
   inline std::error_code make_error_code(BitcodeError E) {
     return std::error_code(static_cast<int>(E), BitcodeErrorCategory());
   }
 
   class BitcodeDiagnosticInfo : public DiagnosticInfo {
     const Twine &Msg;
     std::error_code EC;