[IRGen] Dealloc on-stack metadata/wtable packs on the dominance frontier. #66201
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@swift-ci please test source compatibility |
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The source compat failures match the baseline failures. |
slavapestov
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If the -enable-pack-metadata-stack-promotion[=true] flag is passed, skip eager heapification.
Provide template instantiations of llvm::DenseMapInfo at swift::irgen::Address and swift::irgen::StackAddress.
Just pull the notion that the alloc corresponds to operand 0 into a helper method.
Stop requiring that allocation instructions produce single values.
Both stackAlloc and unprotectedStackAlloc are paired with stackDealloc builtins.
The algorithm requires no critical edges, but that doesn't mean require ownership. Remove the assert to allow the utility to be called from code where the caller has manually split edges. In the fullness of time, there should no passes should introduce critical edges.
The new alloc_pack_metadata and dealloc_pack_metadata are inserted as part of IRGen lowering. The former indicates that the next instruction might result in on-stack pack metadata being emitted. The latter indicates that this is the position at which metadata emitted on behalf of its operand should be cleaned up.
When lowering a SIL function, if it bears the no_onstack_pack_metadata annotation, disable on-stack pack metadata.
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.
In debug builds, before SIL function emission, pass over the function to collect cleanups. After emitting an instruction for which an on-stack metadata/wtable pack was emitted, assert that there were cleanups for it in the function.
Rather than emitting markers for every single instruction of the relevant sorts, check whether the instructions' types involve packs. Only record them as potential on-stack pack metadata emitters if they do.
Set the flag and updated the tests.
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Deallocate dynamic allocas done for metadata/wtable packs. These
stackrestorecalls are inserted on the dominance frontier and then stack nesting is fixed up. That was achieved as follows:Added a new IRGen pass
PackMetadataMarkerInserter; italloc_pack_metadatajust before instructions that could allocate pack metadata on the stack anddealloc_pack_metadataon the dominance frontier of those instructionsDuring IRGen, the allocations done for metadata/wtable packs are recorded and
IRGenSILFunctionassociates them with the instruction that lowered. It must be the instruction after somealloc_pack_metadatainstruction. Then, when visiting thedealloc_pack_metadatainstructions corresponding to thatalloc_pack_metadata, deallocate those packs.See individual commits for more details.
rdar://110268881