A plea from Rakudo-land

Vasily Chekalkin bacek at bacek.com
Sun Jul 12 03:22:56 UTC 2009

Patrick R. Michaud wrote:
> Another update on current GC failures affecting Rakudo.

Ok, after many iterations and rumbling around I want to apply next patch 
  to Parrot.

1. PARROT_ASSERT in hash.c enforce contract about "constant" PMC usage. 
Because for "constant" PMC *all* contents _including_ keys must be 
allocated from constant pool.

2. Changing HLL_info from constant_pmc_new to pmc_new for same reason. 
OrderedHash.push_pmc creates new keys. And those keys are not allocated 
from _constant_ pool. And this is likely main problem of "Method 'succ' 
not found".

3. Clearing constant flag on PMC thawing. Comment in packfile.c:3999
      * TODO use thaw_constants
      * current issue: a constant Sub with attached properties
      *                doesn't GC mark the properties
      * for a constant PMC *all* contents have to be in the constant pools
     pmc         = Parrot_thaw(interp, image);

Which means when we unpack PackFile_Constant we actually allocate from 
non-constant pool. But for aggregate PMCs (such Hash) we preserve 
freezed flags including PObj_constant_FLAG. Which lead us to hash_visit 
where we create new non-constant keys.

Honestly, I wish to eliminate constant_pool totally. It's very-very 
premature optimisation. And complexity of using it is similar to 


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