Nate Chandler d1ec1e6693 [IRGen] Dealloc metadata packs on dom frontier. ...

Deallocate dynamic allocas done for metadata/wtable packs.  These
stackrestore calls are inserted on the dominance frontier and then stack
nesting is fixed up.  That was achieved as follows:

Added a new IRGen pass PackMetadataMarkerInserter; it
- determines if there are any instructions which might allocate on-stack
  pack metadata
- if there aren't, no changes are made
- if there are, alloc_pack_metadata just before instructions that could
  allocate pack metadata on the stack and dealloc_pack_metadata on the
  dominance frontier of those instructions
- fixup stack nesting

During IRGen, the allocations done for metadata/wtable packs are
recorded and IRGenSILFunction associates them with the instruction that
lowered.  It must be the instruction after some alloc_pack_metadata
instruction.  Then, when visiting the dealloc_pack_metadata instructions
corresponding to that alloc_pack_metadata, deallocate those packs.

2023-06-05 08:11:28 -07:00

836 B

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