Invalid wasm (trying to access parent frame stack values) with latest nightly (wasm32-unknown-unknown)

[DarrenTsung]

Hi, I'm running into an issue I believe introduced in the nightly compiler sometime after nightly (8ff4b4206 2018-05-08). I filed another issue in wasm-bindgen earlier: rustwasm/wasm-bindgen#199, but believe that it is a compiler change that caused this to occur.

I've created a test-case repository here: https://github.com/DarrenTsung/wasm-validation-64.

On my current nightly, the wasm code produced fails validation with wasmi with the error: Trying to access parent frame stack values., but this does not occur with nightly-2018-05-09.

I've included the rustc version that I ran against in the test-case repository, but please let me know if any other information would be useful!

[alexcrichton]

Thanks for the report here @DarrenTsung, I've been able to reproduce with these instructions!

It looks like somewhere along the way LLVM is producing an invalid object file for wasm. Using wasm-validate I get:

error: type mismatch in call, expected [i32, i32] but got [i32]

Sure enough using llc to reassemble one of the intermediate bytecode files I'm also able to generate the same error.

I've opened an upstream bug to track this for LLVM

[alexcrichton]

This has been fixed in upstream LLVM and I've sent a PR to update our LLVM with that fix