1093158 - Functions created with .bind use a lot of stack space

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

e.g. http://people.mozilla.org/~khuey/test_1083107.html

Comment 1

[Jan de Mooij [:jandem]]

Yes, our bind implementation is pretty terrible atm for multiple reasons. 

Bug 1000780 will hopefully fix this...

Comment 2

[Jan de Mooij [:jandem]]

Oh and we use more stack space because we have to call into C++ (see CallOrConstructBoundFunction) and then back into JIT code for every function call. Entering and leaving JIT code involves various trampolines and pushing more C++ frames.

Normal function calls will stay in JIT code or are even inlined in Ion, meaning there's a lot less overhead. Bug 1000780 (self-hosting bind) should also keep us in JIT code.

Comment 3

[Till Schneidereit [:till]]

I just tested this with a new patch in bug 1000780: at least in the OS X shell, I get about 10x as many iterations as before (~2300 instead of 210, with the unbound case varying wildly between 4600 and 6500; the OS X shell stack limit is laughably low).

Comment 4

[Till Schneidereit [:till]]

This was indeed fixed by bug 1000780. I get 67k iterations for the bound function vs 95k for the unbound one in the browser and 5942 / 6813 in the shell. While there's still a delta between the two, there's not much we can do about that, since the stack frames just contain more data.

Other browsers:
Chrome Canary 8956 / 9844 (!)
Safari 9.0.2 5640 / 28156