Invalid execution of optimized smallpt binary

[vshymanskyy]

./wasm3 smallpt-ex.wasm 4 32 | sha1sum
Produces (correctly) ea05d85998b2f453b588ef76a1256215bf9b851c

However if smallpt-ex.wasm is build with -O3 or -Os flags, it produces wrong output.
With -O2 or -Oz, it works as expected. They all execute fine in wasmer.

Pre-built binaries: smallpt.zip

[vshymanskyy]

Looks related to this PR: #175

[vshymanskyy]

After reverting #175 things are better, but -Os build still fails:

$ ./wasm3 smallpt-ex-Os.wasm 4 32 > out-Os.ppm
...
$ sha1sum *.ppm
ea05d85998b2f453b588ef76a1256215bf9b851c  out-O2.ppm
ea05d85998b2f453b588ef76a1256215bf9b851c  out-O3.ppm
b25e6e933fef1ac856e32775706c2ec1dab22ec5  out-Os.ppm
ea05d85998b2f453b588ef76a1256215bf9b851c  out-Os-wasmer.ppm
ea05d85998b2f453b588ef76a1256215bf9b851c  out-Oz.ppm

[vshymanskyy]

Also in this example wasm3 fails with [trap] invalid conversion to integer, but it doesn't happen on browser engines.
music-bug.zip

The zip file contains execution traces of wasm3 and nodejs for comparison.

Steps:

➜ ./wasm3 --repl
wasm3> :load music.wasm
wasm3> :set-global SAMPLERATE 1024
wasm3> :get-global SAMPLERATE
1024.000000:f32
wasm3> playEventsAndFillSampleBuffer
==== wasm backtrace:
  0: 0x0039ca - .unnamed!<unnamed>
  1: 0x003a7e - .unnamed!<unnamed>
  2: 0x0028f4 - .unnamed!<unnamed>
  3: 0x002e01 - .unnamed!fillSampleBuffer
  4: 0x003693 - .unnamed!playEventsAndFillSampleBuffer
Error: [trap] invalid conversion to integer ()

[soundandform]

Made some progress figuring this out. With some tweaking, i can achieve a successful hash on all but I still haven't tracked down the cause of failure.

[vshymanskyy]

@soundandform I can confirm it also fixes the music bug.
@petersalomonsen We can now play your midisynth example 🥳

[vshymanskyy]

@soundandform but it also breaks some other examples from pywasm3 😢

[soundandform]

@soundandform but it also breaks some other examples from pywasm3 😢

@vshymanskyy taking a quick look at pywasm code, this is probably due to the change of call frame, preparing for multi-return. empty slots (= to return count) need to be padded before args.

[vshymanskyy]

oops. will re-check!

…

On Fri, 9 Apr 2021, 20:54 Steven Massey, ***@***.***> wrote: @soundandform <https://github.com/soundandform> but it also breaks some other examples from pywasm3 😢 @vshymanskyy <https://github.com/vshymanskyy> taking a quick look at pywasm code, this is probably due to the change of call frame, preparing for multi-return. empty slots (= to return count) need to be padded before args. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#218 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AALP3FAYTO6Y22Y7RL4GBQLTH45NXANCNFSM4ZYDQFYQ> .

[petersalomonsen]

Awesome that you now can play the midisynth 😀

[vshymanskyy]

@soundandform please check pygame-maze.py example. This one now fails with [trap] invalid conversion to integer. it's not related to arguments layout, as it only runs a single void(void) function.
Also, pywasm3 uses only the public Wasm3 API (those put_arg_on_stack and get_arg_from_stack functions are aptly named).

[vshymanskyy]

@soundandform nevermind, figured it out. The issue was on pywasm3 side, in the generic RawFunction handler.

[vshymanskyy]

I think we can close this, all of the found issues were covered by tests