Function hidden classes (v2)

Revision 2 of this benchmark created on

Description

Functions in v8 have hidden classes like objects, and functions only get fully optimized if using the default hidden class

Preparation HTML

<script type="text/javascript">
var f1 = function (n) {
  return n;
};
var f2 = function (n) {
  return n;
};

f2.toString = function () { return "f2"; };
Object.defineProperty(f2, "displayName", { value: "f2" });
Object.defineProperty(f2, "debugName", { value: "f2" });

Function.prototype.invoke1 = function () {
  return this.apply(null, arguments);
};

Function.prototype.invoke2 = function () {
  return this.apply(null, arguments);
};

Function.prototype.invoke3 = function () {
  return this.apply(null, arguments);
};

var count = 5000;

// Feed information into the ICs for each function
for (var i = 0; i < count; i++) {
  f1.invoke1(1);
  f2.invoke2(1);

  // The IC for invoke3 will get two different hidden class entries, which deoptimizes it
  if (i % 2 == 0)
    f1.invoke3(1);
  else
    f2.invoke3(1);
}
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
Direct (unmodified)
var sum = 0;
for (var i = 0; i < count; i++) {
  sum += f1(i);
}
if (sum != 12497500)
  throw new Error();
ready
Direct (modified)
var sum = 0;
for (var i = 0; i < count; i++) {
  sum += f2(i);
}
if (sum != 12497500)
  throw new Error();
ready
.call (unmodified)
var sum = 0;
for (var i = 0; i < count; i++) {
  sum += f1.call(this, i);
}
if (sum != 12497500)
  throw new Error();
ready
.call (modified)
var sum = 0;
for (var i = 0; i < count; i++) {
  sum += f2.call(this, i);
}
if (sum != 12497500)
  throw new Error();
ready
Consistent IC information (unmodified fn)
var sum = 0;
for (var i = 0; i < count; i++) {
  sum += f1.invoke1(i);
}
if (sum != 12497500)
  throw new Error();
ready
Consistent IC information (modified fn)
var sum = 0;
for (var i = 0; i < count; i++) {
  sum += f2.invoke2(i);
}
if (sum != 12497500)
  throw new Error();
ready
Conflicting IC information (unmodified fn)
var sum = 0;
for (var i = 0; i < count; i++) {
  sum += f1.invoke3(i);
}
if (sum != 12497500)
  throw new Error();
ready
Conflicting IC information (modified fn)
var sum = 0;
for (var i = 0; i < count; i++) {
  sum += f2.invoke3(i);
}
if (sum != 12497500)
  throw new Error();
ready

Revisions

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