388080 - Apparent no-op in GC.cpp

Status: VERIFIED FIXED

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

Description

[Jason Orendorff [:jorendorff]]

In file MMgc/GC.cpp, function void GC::MarkItem(GCWorkItem &wi, GCStack<GCWorkItem> &work), lines 2157-2159:

  2157						// clear queued bit
  2158						*pbits = bits2 & ~(GCAlloc::kQueued << shift);
  2159						*pbits = bits2 | (GCAlloc::kMark << shift);

It looks like line 2159 clobbers the result of line 2158.  So the queued bit is not actually cleared.

Comment 1

[Tommy Reilly]

Line 2158 should just be removed, this code is for items that don't contain pointers which are never queued.    Its not broken, just doing extra work.

Comment 2

[Jason Orendorff [:jorendorff]]

Attachment: remove the no-op line, as suggested in comment #1

I pushed the attached patch (on the strength of treilly's suggestion, not to stand on ceremony).  Changeset 1c5d883131a0.