Stream: git-wasmtime

Topic: wasmtime / issue #5502 fuzzgen: Disable unimplemented ris...

view this post on Zulip Wasmtime GitHub notifications bot (Jan 12 2023 at 16:01):

github-actions[bot] commented on issue #5502:

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view this post on Zulip Wasmtime GitHub notifications bot (Jan 12 2023 at 17:32):

jameysharp commented on issue #5502:

@uweigand, FYI: This PR illustrates what we need to start routinely fuzz-testing additional Cranelift backends. I'd love to start testing s390x on our OSS-Fuzz quota too. For non-x86, OSS-Fuzz can only test that codegen succeeds, not that the generated code runs correctly, but I expect that to be enough to catch many bugs. Of particular interest right now, this should help us catch non-SSA lowerings.

The steps are:

  1. add the s390x feature to the cranelift-codegen dependency in fuzz/Cargo.toml (optionally, you can temporarily remove the other backends there to focus on that one)
  2. run cargo +nightly fuzz run cranelift-icache on any host, and/or cargo +nightly fuzz run cranelift-fuzzgen on an s390x host—whichever you have more CPU cycles available on
  3. as it finds bugs, add backend-specific exceptions for known issues with lowering particular instructions at particular types, as illustrated by this PR

Once the fuzzer runs for an hour without finding new bugs it's probably ready.

These fuzz targets don't yet generate all possible Cranelift instructions, so you won't have to write down exceptions for every unimplemented thing. It's currently limited to scalar types and arithmetic/load/store operations mostly, but we're incrementally expanding coverage.

view this post on Zulip Wasmtime GitHub notifications bot (Jan 19 2023 at 12:45):

uweigand commented on issue #5502:

@jameysharp s390x support PR now posted here: https://github.com/bytecodealliance/wasmtime/pull/5596

Thanks for pointing this out!

Last updated: Dec 23 2024 at 12:05 UTC