Bitcode checking should return 1 upon failure. Bug fix.

Change-Id: Ic0dc7a4cc1a236044963914134676ddf19f8ffcf
diff --git a/lib/bcc/Compiler.cpp b/lib/bcc/Compiler.cpp
index 3e075db..a9460ab 100644
--- a/lib/bcc/Compiler.cpp
+++ b/lib/bcc/Compiler.cpp
@@ -311,8 +311,10 @@
 int Compiler::linkBC(const char *bitcode, size_t bitcodeSize) {
   llvm::OwningPtr<llvm::MemoryBuffer> MEM;
 
-  if (bitcode == NULL || bitcodeSize <= 0)
-    return 0;
+  if (bitcode == NULL || bitcodeSize <= 0) {
+    LOGE("Invalid bitcode for linkBC: bitcode=%p, size=%lu.\n", bitcode, (unsigned long)bitcodeSize);
+    return 1;
+  }
 
   if (mModule == NULL) {
     setError("No module presents for linking");