779975 - ref count ScriptSource

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[:Benjamin Peterson]

Right now, ScriptSource is hacked onto the GC. This creates icky things like attachToRuntime and the IGC hacks in JSScript::setScriptSource. Since ScriptSource doesn't contain any structs, it would be easier to reference count script sources. Reference counting would also free the source as soon as the last script owning it disappeared instead of waiting for full GC.

Comment 1

[:Benjamin Peterson]

Attachment: implementing ref counting

The only slightly tricky part is that MemoryMetrics has to use a HashSet to avoid counting the same source multiple times.

Comment 2

[Jason Orendorff [:jorendorff]]

Comment on attachment 648471 [details] [diff] [review]
implementing ref counting

Review of attachment 648471 [details] [diff] [review]:
-----------------------------------------------------------------

Wonderful. This is so much better than the GC hack.

My experience is, anything like this eventually gets turned into a real GC-thing; but if that happens in time, fine, and there's no rush.

::: js/src/jsscript.cpp
@@ +1293,2 @@
>      JS_ASSERT(ready());
>      // data is a union, but both members are pointers to allocated memory, so

Pre-existing style nit: while you're in here, please put a blank line before this comment (since it is not at the top of a block)

Comment 3

[:Benjamin Peterson]

https://hg.mozilla.org/integration/mozilla-inbound/rev/fa77c8c2a346

Comment 4

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/fa77c8c2a346