emit a specific error when the input file is empty. This fixes

an annoyance of mine when working on tests: if the input .ll file
is broken, opt outputs an error and generates an empty file.  FileCheck
then emits its "ooh I couldn't find the first CHECK line, scanning
from ..." which obfuscates the actual problem.

llvm-svn: 125193

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/utils/FileCheck/FileCheck.cpp b/llvm/utils/FileCheck/FileCheck.cpp
index a4aa693448b..5d4cb0c0c5f 100644
--- a/llvm/utils/FileCheck/FileCheck.cpp
+++ b/llvm/utils/FileCheck/FileCheck.cpp
@@ -659,6 +659,11 @@ int main(int argc, char **argv) {
   }
   MemoryBuffer *F = File.take();
 
+  if (F->getBufferSize() == 0) {
+    errs() << "FileCheck error: '" << InputFilename << "' is empty.\n";
+    return 1;
+  }
+  
   // Remove duplicate spaces in the input file if requested.
   if (!NoCanonicalizeWhiteSpace)
     F = CanonicalizeInputFile(F);