ExecutablePools have manual refcounting. This is error-prone, see bug 635968. We should change it to something less error-prone. I see two options. 1. Automatic refcounting with a smart pointer class. It's the "right" (sophisticated) way to do it, and would allow memory to be freed as soon as possible. 2. Manual management. This is the worse-is-better approach and it will only be suitable if there are a small number of lifetimes. AFAIK we have the following lifetimes: - PICs are purged every GC - MICs are purged on GCs if shape regeneration has occurred - Other JM code is purged when a compartment dies That points to two basic lifetimes, PIC and non-PIC (I'm assuming shape regeneration is rare enough that MICs could go in with normal code without causing much fragmentation, though I could be wrong about that). Bug 631045 is a step in the right direction for this (and worth doing even if we go with auto-refcounting, due to reduced fragmentation). But then there's bhackett's half-life purging stuff, I don't know how that fits in.

(In reply to comment #0) > ExecutablePools have manual refcounting. This is error-prone, see bug 635968. > We should change it to something less error-prone. I see two options. > > 1. Automatic refcounting with a smart pointer class. It's the "right" > (sophisticated) way to do it, and would allow memory to be freed as soon as > possible. I think this is important but not urgent, so the "right" way seems best.

(In reply to comment #1) > > I think this is important but not urgent, so the "right" way seems best. It's definitely important. Urgency isn't a factor in the choice between (1) and (2), but I deliberately put "right" in scare quotes... http://en.wikipedia.org/wiki/Worse_is_better. I favour (2) if there are a small number of lifetimes.

Another thing in favour of (2): we currently have an ExecPoolVector in each PIC (in BasePolyIC, to be specific). With approach (2) we wouldn't need this, and so we'd save one word per PIC.

Baseline/Ion use GC-allocated IonCode objects, refcounting is handled when constructing/finalizing these objects.