FileCheck: print input on errors

[dvyukov]

Summary

FileCheck output is unactionable without intput. Print input on errors.

Are there any downsides of this?
I am ready to bargain about details like output only stdin.

[silvas]

My only concern would maybe be verbosity (sometimes the input could be
quite large and drown out everything else). But overall this solves an
issue that I've run into too.

I would also suggest to print something more clear like "Begin FileCheck
Input: ***" << .... << "End FileCheck Input: ***" to
distinguish it from the surrounding and be easy to search for (in case of a
very large input).

• Sean Silva

[chapuni]

FYI, see also http://reviews.llvm.org/D20105

[dvyukov]

FYI, see also http://reviews.llvm.org/D20105

Answered there. I don't understand why printing input is not the default.

utils/FileCheck/FileCheck.cpp

for ( ; i != j; ++i) {
 
       CheckRegion = CheckRegion.substr(MatchPos + MatchLen);
     }
 
     if (j == e)
       break;
   }
 
+  if (hasError)
+    errs() << "Input:" << '\n' << Buffer.str() << '\n';
+
   return hasError ? 1 : 0;
 }