805904 - Remove unnecessary javascript function names

Status: RESOLVED INCOMPLETE

(Firefox for Android Graveyard :: General, defect)

Description

[Kartikaya Gupta (email:[e-mail])]

As of FF 17, the JS engine can infer function names from "anonymous" functions, so we shouldn't need to duplicate them. i.e. instead of

name: function debug_name(arguments) {
}

we can just do

name: function(arguments) {
}

See http://javascript-reverse.tumblr.com/post/34328529526/javascript-function-name-inference-aka-stop-function

Comment 1

[Tom S. (please needinfo tschuster)]

We could probably modify the JS parser to dump function lines and scripts where we name functions, but have sufficient name inference. And then put it on the try server.

Comment 2

[Tom S. (please needinfo tschuster)]

Attachment: js/src modification

I modified the NameFunctions code so it dumps out unnecessary names.

Comment 3

[Tom S. (please needinfo tschuster)]

Attachment: python data scaper

Running this very ugly python script, produces a list of all functions that could be simplified.

Comment 4

[Tom S. (please needinfo tschuster)]

Attachment: output

Running the script produces this output. This is only for code in chrome:// that is also hit by mochitests. Now we need start looking at renaming this stuff :)

Comment 5

[Kartikaya Gupta (email:[e-mail])]

The output is for desktop, right? Can we get one for Fennec as well?

Comment 6

[Kartikaya Gupta (email:[e-mail])]

(Specifically we have a different browser.js than desktop so the output here doesn't apply to Fennec's browser.js)

Comment 7

[Tom S. (please needinfo tschuster)]

We can probably parse the result of this try push: https://tbpl.mozilla.org/?tree=Try&rev=e7e93b94fcf2.

Comment 8

[Kartikaya Gupta (email:[e-mail])]

The try push above failed on non-debug builds, and the debug build for Android doesn't run any tests. I'm not sure why the Linux build log itself has the output (does the JS compiler frontend get run during the build process itself?) but the Android one sadly does not.

I tried taking your patch and applying it to my local build which worked fine, but then starting Fennec on a device didn't print out the name info like I thought it would.