[PATCH] D28684: [Support/Compression] - Change zlib API to return Error instead of custom status.

[Rafael Avila de Espindola via llvm-commits]

George Rimar <grimar at accesssoftek.com> writes:

>>> +  Error E = zlib::compress(StringRef(UncompressedNameStrings),
>>> +                           CompressedNameStrings, zlib::BestSizeCompression);
>>> +  if (E)
>>>      return make_error<InstrProfError>(instrprof_error::compress_failed);
>>
>>This does't handle the error, does it? Do we have a test that covers it?
>
> I think it does. What do you think is wrong here ?
> I am not sure about if we have test, but checking 
> if (Error) { ... }
> seems to be a common practice I believe. Examples from llvm:
>
>  1)     Error E = CVTD.dump(Record, TDV);
>       if (E) {
>         logAllUnhandledErrors(std::move(E), errs(), "error: ");
>         llvm_unreachable("produced malformed type record");
>       }
>
> 2)   Error E = debugMiscompilation();
>       if (!E)
>         return Error::success();
>
> And I am pretty sure I debbugged that and other places when wrote it.

If I remember correctly, an "if (E)" is sufficient when E doesn't
actually contain an error, but if it contains an error E must be handled
or propagated.

Cheers,
Rafael