as-heap-analyzer

assemblyscript heap dump analysis tooling

How to use

- install as-heap-analyzer

``bash
npm i -D as-heap-analyzer
`

- Before you build assemblyscript to wasm, add --transform as-heap-analyzer/transform/addHeapAnalyzerInfo.mjs
or add following line in asconfig.json

`json
"transform": ["as-heap-analyzer/transform/addHeapAnalyzerInfo.mjs"]
`

$3

- run code and use analysis function

`js
import { memory } from "../build/debug.js";
import { readFileSync } from "fs";
import { analysis } from "as-heap-analyzer/dist/index.js";
import assert from "assert";

const wasm = readFileSync("build/debug.wasm");
const memoryUsage = analysis(memory, wasm);
memoryUsage.forEach((v, k) => console.log(${k} use ${v} bytes));
`

$3

- run code and use analysis function

`js
import { memory } from "./build/release.js";
import { analysis } from "as-heap-analyzer/dist/index.js";

const wasm = (await (await fetch(new URL("build/release.wasm", import.meta.url))).body.getReader().read()).value;
const memoryUsage = analysis(new Uint8Array(memory.buffer), wasm);
memoryUsage.forEach((v, k) => {
document.body.innerText += ${k} use ${v} bytes\n;
});
`

$3

- use self-diagnosis API in assemblyscript to trace memory information to log

`ts
import { dumpUsedMemoryDetail } from "as-heap-analyzer/assembly/index";

trace(dumpUsedMemoryDetail());
`

- run cli

`bash
npx as-heap-analyzer frame
`

- copy and paste self-diagnosis result from log to cli

- the result should be:

`
total memory usage is 48300
class ~lib/arraybuffer/ArrayBuffer use 544 bytes
class assembly/index/A use 6400 bytes
class ~lib/array/Array use 48 bytes
class assembly/index/B use 32 bytes
``