- // Replace the updatee with an indirection
- //
- // Warning: if we're in a loop, more than one update frame on
- // the stack may point to the same object. Be careful not to
- // overwrite an IND_OLDGEN in this case, because we'll screw
- // up the mutable lists. To be on the safe side, don't
- // overwrite any kind of indirection at all. See also
- // threadSqueezeStack in GC.c, where we have to make a similar
- // check.
- //
- if (!closure_IND(((StgUpdateFrame *)frame)->updatee)) {
- // revert the black hole
- UPD_IND_NOLOCK(((StgUpdateFrame *)frame)->updatee,
- (StgClosure *)ap);
- }
+ // Perform the update
+ // TODO: this may waste some work, if the thunk has
+ // already been updated by another thread.
+ UPD_IND_NOLOCK(((StgUpdateFrame *)frame)->updatee,
+ (StgClosure *)ap);
+