973091 - Don't abort on arguments & setarg if arguments doesn't escape and has no setelems

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, defect)

Description

[Shu-yu Guo [:shu]]

Currently if a script both has the |arguments| object and a SETARG, Ion barfs. This is a huge perf hit for functions that implement default arguments more correctly than checking for undefined, e.g.:

function foo(a) {
  a = arguments.length < 1 ? defaultArg : a;
  ...
}

Comment 1

[Shu-yu Guo [:shu]]

Kannan, what's needed to reland bug 921120? Maybe this is just a matter of that.

Comment 2

[Till Schneidereit [:till]]

Heh, mid-air collided while trying to CC Kannan.

Comment 3

[Kannan Vijayan [:djvj]]

(In reply to Shu-yu Guo [:shu] from comment #1)
> Kannan, what's needed to reland bug 921120? Maybe this is just a matter of
> that.

Proper fix for bug 957475.

Comment 4

[Till Schneidereit [:till]]

Shu, I don't know what your test case was. Can you (I'm being optimistic) confirm that this is fixed?

Comment 5

[Shu-yu Guo [:shu]]

(In reply to Till Schneidereit [:till] from comment #4)
> Shu, I don't know what your test case was. Can you (I'm being optimistic)
> confirm that this is fixed?

Ion is now able to compile SETARG even in the presence of an arguments binding.