654943 - MMgc API cleanup

Status: RESOLVED WONTFIX

(Tamarin Graveyard :: Garbage Collection (mmGC), defect, P2)

Description

[Lars T Hansen]

The MMgc API should be cleaned up and made safer and easier to use.

This will include at least:

- Making GC::Alloc and GC::Callo private to the GC, thus enforcing the rule
  about subclassing GCObject, GCTraceableObject, GCFinalizedObject, or
  RCObject for all managed types, not having implicit subclasses of
  GCObject.  (This is orthogonal to headerless BiBoP allocation for double
  and float - just for the record.)

- Making GC::Free private, because dangling pointers are bad and GC::Free
  tends to be used for evil as much as for good.

- Introducing managed array types to be used where GC::Alloc and GC::Calloc
  are currently used.

- Entirely removing DRC, DRCWB, DWB and introducing GCMember everywhere.

- Possibly other SafeGC tasks.

- Documentation cleanup and development.

This is a tracker bug for concrete tasks, please do not post patches here.  But ideas and dependent bugs are welcome.

Comment 1

[Lars T Hansen]

It's an API bug that Alloc and Calloc cannot take a request of size zero.  In principle that should be fixed.

However, if Alloc and Calloc are made private to MMgc and only available to specially blessed code (such as managed array types) then it's probably OK to keep the restriction that the size of the request can't be zero, because there will be few clients and they can easily check that requirement.

Comment 2

[Tommy Reilly]

I morphed my "avoid container calc bug" into a "remove WB/WBRC manual write barrier" bug.

Comment 3

[Steven Johnson]

FYI, having nativegen.py emit GCMember<> requires a lot of fiddling with Flash/AIR header files; I am *almost* done with that and hopefully will be able to land it this week.

Comment 4

[Lars T Hansen]

(In reply to comment #3)
> FYI, having nativegen.py emit GCMember<> requires a lot of fiddling with
> Flash/AIR header files; I am *almost* done with that and hopefully will be
> able to land it this week.

That's great news!

Comment 5

[Sylvestre Ledru [:Sylvestre]]

Tamarin is a dead project now. Mass WONTFIX.

Comment 6

[Sylvestre Ledru [:Sylvestre]]

Tamarin isn't maintained anymore. WONTFIX remaining bugs.