webassembly/api: Allocate code data on C heap when running Python code.

[dpgeorge]

Otherwise Emscripten allocates it on the Emscripten C stack, which will overflow for large amounts of code.

Fixes issue #14307.

[dpgeorge]

@WebReflection this should fix the issue you are seeing when trying to run large code strings.

[dpgeorge]

Find a compiled version of this PR here for testing: https://micropython.org/resources/wasm/micropython.mjs (also has https://micropython.org/resources/wasm/micropython.wasm).

[WebReflection]

if len always needs a + 1 (for null code \x00 I suppose) why isn't this just const len = Module.lengthBytesUTF8(code) + 1; instead? Not a blocker, just a silly question!

[dpgeorge]

Module.stringToUTF8 will always add a null byte at the end, so there must be enough room for it.

But, below in the call to mp_js_do_exec_async, we pass just len.

[WebReflection]

I can confirm this fixes the presented use-case/issue we had 🙏

index.txt

rename this file as index.html in your test folder, download both https://micropython.org/resources/wasm/micropython.mjs and https://micropython.org/resources/wasm/micropython.wasm in it, change eventually the host port in the <mpy-config> if different from 8080, bootstrap a server and see no issue whatsoever, with the page showing a Thank You! text in the body.

[ntoll]

Bravo

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.39%. Comparing base (49ce7a6) to head (7c7e07e).

❗ Current head 7c7e07e differs from pull request most recent head 9c7f065. Consider uploading reports for the commit 9c7f065 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #14318   +/-   ##
=======================================
  Coverage   98.39%   98.39%           
=======================================
  Files         161      161           
  Lines       21204    21204           
=======================================
  Hits        20864    20864           
  Misses        340      340           

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[github-actions]

Code size report:

   bare-arm:    +0 +0.000% 
minimal x86:    +0 +0.000% 
   unix x64:    +0 +0.000% standard
      stm32:    +0 +0.000% PYBV10
     mimxrt:    +0 +0.000% TEENSY40
        rp2:    +0 +0.000% RPI_PICO
       samd:    +0 +0.000% ADAFRUIT_ITSYBITSY_M4_EXPRESS

[dpgeorge]

Also added a fix for initialising Module with the latest Emscripten.

[WebReflection]

@dpgeorge do you mind publishing this latest version to npm so we can also bump it? Thanks!

[dpgeorge]

The latest master with this PR merged is available here: https://www.npmjs.com/package/@micropython/micropython-webassembly-pyscript/v/1.22.0-335