[PATCH] D42414: [llvm-opt-fuzzer] Avoid adding incorrect inputs to the fuzzer corpus

[Igor Laevsky via Phabricator via llvm-commits]

igor-laevsky added inline comments.


================
Comment at: tools/llvm-opt-fuzzer/llvm-opt-fuzzer.cpp:68-73
   if (verifyModule(*M, &errs())) {
     errs() << "mutation result doesn't pass verification\n";
     M->dump();
-    abort();
+    // Avoid adding incorrect test cases to the corpus.
+    return 0;
+  }
----------------
bogner wrote:
> Can we drop this part and only verify after the reload?
I'm not sure how bitcode writer will behave on the invalid module. I would suspect that this verification is fast compared to the save/reload part. 


================
Comment at: tools/llvm-opt-fuzzer/llvm-opt-fuzzer.cpp:92-93
+  if (!NewM || verifyModule(*NewM, &errs())) {
+    errs() << "mutator failed to re-read the module\n";
+    M->dump();
+    return 0;
----------------
bogner wrote:
> Where does this output go when running the fuzzer? Will we see / be able to act on this information?
This goes to the stderr and I assume this will be visible in the ClusterFuzz logs. 


https://reviews.llvm.org/D42414