stencil-eager-delazify.js

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// |jit-test| skip-if: helperThreadCount() === 0 || isLcovEnabled()

// Extra GCs can empty the StencilCache to reclaim memory. This lines

// re-configure the gc-zeal setting to prevent this from happening in this test

// case which waits for the cache to contain some entry.

if ('gczeal' in this)

  gczeal(0);

let u = 0;

// At each function, create `width` inner functions.

let width = 2;

// Depth of inner functions.

let depth = 4;

// Number of additional parser & delazification workload running concurrently

// with the one we are attempting to measure, such that we can see differences

// in the report of `isInStencilCache`.

let load = 14;

// Return the number of function generated by a to `depthFirstExec` given the

// same parameters.

function count(w, d) {

  return (Math.pow(w, d + 1) - 1) / (w - 1);

// Generate a source code with a large number of inner functions, such that

// eager delazification can be observe while running JS code concurrently.

function depthFirstExec(indent, name, w, d) {

  let fun = `${indent}function ${name} (arg) {\n`;

  let inner = "";

  let val = `arg + isInStencilCache(${name})`;

  if (d > 0) {

    for (let i = 0; i < w; i++) {

      inner += depthFirstExec(`${indent}  `, `${name}_${i}`, w, d - 1);

      val = `${name}_${i}(${val})`;

  fun += inner;

  fun += `${indent}  return ${u} + ${val} - ${u};\n`;

  fun += `${indent}}\n`;

  u += 1;

  return fun;

};

const options = {

  fileName: "depthFirstExec.js",

  lineNumber: 1,

  eagerDelazificationStrategy: "ConcurrentDepthFirst",

};

let script = depthFirstExec("", "raceMe", width, depth);

let jobs = [];

for (let i = 0; i < load; i++) {

  // Spin up extra compilation workload...

  jobs.push(offThreadCompileToStencil(script, options));

const stencil = finishOffThreadStencil(jobs[0]);

evalStencil(stencil, options);

waitForStencilCache(raceMe);

let start = raceMe(0);

let mid = raceMe(0);

let end = raceMe(0);

// The garbage collector should clear the cache and suppress all delazification

// tasks.

gc();

let afterGc = raceMe(0);

assertEq(1 <= start, true);

assertEq(start <= mid, true);

assertEq(mid <= end, true);

assertEq(end <= count(width, depth), true);

assertEq(afterGc, 0);