WASM -> TypeError: Cannot read property 'cwrap' of undefined

[sbstcano]

Hi,
I'm trying to use wasm with facemesh but keep getting this when trying to set wasm as backend.
I'm using version 2.3.0. And it's an Angular 9 project.

import * as tf from '@tensorflow/tfjs-core'
import * as facemesh from '@tensorflow-models/facemesh'
import {setWasmPath} from "@tensorflow/tfjs-backend-wasm"

setWasmPath(`https://cdn.jsdelivr.net/npm/@tensorflow/tfjs-backend-wasm@2.3.0/dist/tfjs-backend-wasm.wasm`)

tf.setBackend('wasm')

TypeError: Cannot read property 'cwrap' of undefined
    at Object.setupFunc (tf-backend-wasm.esm.js:17)
    at engine.js:161
    at Array.forEach (<anonymous>)
    at Engine.setupRegisteredKernels (engine.js:159)
    at Engine.setBackend (engine.js:152)
    at Module.setBackend (globals.js:258)
    at Module../src/app/enrollment/enrollment.component.ts (enrollment.component.ts:20)
    at __webpack_require__ (bootstrap:79)
    at Module../src/app/app-routing.module.ts (main.js:450)
    at __webpack_require__ (bootstrap:79)

[deel77]

I think I have identified main problem. Angular is overwriting Promise.resolve() function with its own wrapping function in order to use ZoneAwarePromise as a return type in order to automatically trigger change detection after promise finishes.

And TF-Core is using following code to test if created backend is Promise (which is Promise type only for WASM backend, as to my knowledge):

// Test if the factory returns a promise.
if (Promise.resolve(backend) === backend) {

see https://github.com/tensorflow/tfjs/blob/master/tfjs-core/src/engine.ts#L294

and this type of test does not return true as return type of Promise.resolve(backend) is not same Promise but ZoneAwarePromise wrapper of original Promise.

I have tried to run tf.setBackend('wasm') inside ngZone.runOutsideAngular() but it does not help. I would try something more.

[deel77]

With changes proposed in pull request #3993 I was able to make it work in Angular 9 and Angular 10 project ... still having problems with SIMD version but basic WASM backend is working now.

[google-ml-butler]

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