1740683 - Support extra formals when replacing the rest array for MApplyArray and MConstructArray

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, task, P3)

Description

[André Bargull [:anba]]

Replacing the rest array for MApplyArray and MConstructArray uses MApplyArgs resp. MConstructArgs. If we want to support replacing rest arrays when extra formals are present, MApplyArgs and MConstructArgs need to be updated to handle this case.

// Rest array is replaced when no extra formals are present.
function noExtraFormals(...rest) {
  return f(...rest);
}

// Rest array is _not_ replaced when extra formals are present.
function extraFormals(a, ...rest) {
  return f(...rest);
}

Comment 1

[André Bargull [:anba]]

Attachment: Bug 1740683: Scalar replace rest array spread calls with extra formals. r=iain!

Pass through the number of formals, so we know how many initial arguments we have to skip
in CodeGenerator::emitPushArguments(). The actual number of arguments (argc) for
M(Apply|Construct)Args is computed through Math.max(numActuals - numFormals, 0).

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b8defeb29902
Scalar replace rest array spread calls with extra formals. r=iain

Comment 3

[Cristian Tuns]

https://hg.mozilla.org/mozilla-central/rev/b8defeb29902