1379461 - Return RegExpShared* instead of using bool + outparam

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement)

Description

[Jan de Mooij [:jandem]]

Attachment: Patch

There are a lot of places where we can return RegExpShared* instead of returning bool and using a RegExpShared outparam. This is cleaner and lets us eliminate a bunch of unnecessary roots.

This is a very mechanical patch. I did have to beef up the FORWARD macro in the js/ipc CPOW code to let us return nullptr on failure instead of false.

Comment 1

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/3a0a2ffe803b
Refactor code to return RegExpShared* directly instead of using bool + outparam. r=evilpie

Comment 2

[Carsten Book [:Tomcat]]

backed out for hazard failure like https://treeherder.mozilla.org/logviewer.html#?job_id=113286186&repo=mozilla-inbound

Comment 3

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/8dad48102b13
Backed out changeset 3a0a2ffe803b for hazard failure

Comment 4

[Jan de Mooij [:jandem]]

Attachment: Suppress bogus GC function

We use the macro below in the CPOW code.

The analysis thinks that when the return value is a RegExpShared*, it's live across a GC call: AUTO_PROFILER_LABEL macro -> ~AutoProfilerLabel destructor.

This is bogus because ~AutoProfilerLabel has an indirect call but definitely can't GC.

I think the easiest fix is to teach the analysis that ~AutoProfilerLabel cannot GC. Unfortunately this code is in mozglue so I don't think we can use our SuppressGCAnalysis class for this.

This patch adds an annotation and I get a green analysis build with this on Try.

#define FORWARD(call, args, failRetVal)                                 \
    AUTO_PROFILER_LABEL(__func__, JS);                                  \
    WrapperOwner* owner = OwnerOf(proxy);                               \
    if (!owner->active()) {                                             \
        JS_ReportErrorASCII(cx, "cannot use a CPOW whose process is gone"); \
        return failRetVal;                                              \
    }                                                                   \
    if (!owner->allowMessage(cx)) {                                     \
        return failRetVal;                                              \
    }                                                                   \
    {                                                                   \
        CPOWTimer timer(cx);                                            \
        return owner->call args;                                        \
    }

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/707b8c089de2
Refactor code to return RegExpShared* directly instead of using bool + outparam. r=evilpie,sfink

Comment 6

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/707b8c089de2