807179 - Give JSPropertyDescriptor a constructor

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Andrew McCreight [:mccr8]]

JSPropertyDescriptor is a struct, which means you have to remember to initialize it, which causes badness if you don't. Right now, I think we do this at the API boundary, but maybe we can avoid that. There's also code like in NativeToString in BindingUtils.cpp that would be a little neater if we had better ways to initialize these.

Comment 1

[Luke Wagner [:luke]]

I don't know what is being generated, but I thought these JSPropertyDescriptor things were globally allocated.  In that case, it would be bad for startup time if there were a lot of them and they all had constructor calls.

Comment 2

[Andrew McCreight [:mccr8]]

The ones I'm familiar with, from the browser side, are on the stack, but perhaps there are a bunch in the engine, too.

Comment 3

[Luke Wagner [:luke]]

I guess you could add a constructor with printf and see how many happen before main() :)

Comment 4

[Bobby Holley (:bholley)]

Attachment: Add a constructor for JSPropertyDescriptor. v1

This is a total footgun. Attaching a patch.

Luke, are you sure you're not talking about JSPropertySpecs? I'm not aware of
anywhere we statically allocate JSPropertyDescriptors...

Comment 5

[Luke Wagner [:luke]]

Heh, yes, I am confusing JSPropertySpec with JSPropertyDescriptor.  Carry on.

Comment 6

[Bobby Holley (:bholley)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/e5b6c62c62ad

Comment 7

[Andrew McCreight [:mccr8]]

Yay! Some of JSAutoPropertyRooter can probably also be torn out at some point.

Comment 8

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/e5b6c62c62ad