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

[Justin Bogner via Phabricator via llvm-commits]

bogner accepted this revision.
bogner added a comment.
This revision is now accepted and ready to land.

I think this is okay to go in, with the caveat that we need a plan for fixing up the verifier and removing this.



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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;
+  }
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igor-laevsky wrote:
> 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. 
Are you set up to measure this? It'd be nice to qualify that claim.


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Comment at: tools/llvm-opt-fuzzer/llvm-opt-fuzzer.cpp:83-85
+  // There are some invariants which are not checked by the verifier in favor
+  // of having them checked by the parser. They may be considered as bugs in the
+  // verifier and should be fixed there. However until all of those are covered
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Interestingly, it would be trivial to write a fuzzer that finds these verifier bugs at this point. Maybe we should do that as a way to move towards a state where we can remove the redundant checks?


https://reviews.llvm.org/D42414