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82553384d1
refs #24929, partially reverts #23403 Instead of using `Table[ItemId, T]`, the old algorithm is brought back into `TIdTable[T]` to prevent a performance regression. The inheritance removal from #23403 still holds, only `ItemId`s are stored.
93 lines
3.0 KiB
Nim
93 lines
3.0 KiB
Nim
import std/[tables]
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import ast, astalgo
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type
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LayeredIdTableObj* {.acyclic.} = object
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## stack of type binding contexts implemented as a linked list
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topLayer*: TypeMapping
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## the mappings on the current layer
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nextLayer*: ref LayeredIdTableObj
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## the parent type binding context, possibly `nil`
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previousLen*: int
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## total length of the bindings up to the parent layer,
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## used to track if new bindings were added
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const useRef = not defined(gcDestructors)
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# implementation detail, only arc/orc doesn't cause issues when
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# using LayeredIdTable as an object and not a ref
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when useRef:
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type LayeredIdTable* = ref LayeredIdTableObj
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else:
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type LayeredIdTable* = LayeredIdTableObj
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proc initLayeredTypeMap*(pt: sink TypeMapping = initTypeMapping()): LayeredIdTable =
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result = LayeredIdTable(topLayer: pt, nextLayer: nil)
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proc shallowCopy*(pt: LayeredIdTable): LayeredIdTable {.inline.} =
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## copies only the type bindings of the current layer, but not any parent layers,
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## useful for write-only bindings
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result = LayeredIdTable(topLayer: pt.topLayer, nextLayer: pt.nextLayer, previousLen: pt.previousLen)
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#copyIdTable(result.topLayer, pt.topLayer)
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proc currentLen*(pt: LayeredIdTable): int =
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## the sum of the cached total binding count of the parents and
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## the current binding count, just used to track if bindings were added
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pt.previousLen + pt.topLayer.counter
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proc newTypeMapLayer*(pt: LayeredIdTable): LayeredIdTable =
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result = LayeredIdTable(topLayer: initTypeMapping(), previousLen: pt.currentLen)
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when useRef:
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result.nextLayer = pt
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else:
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new(result.nextLayer)
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result.nextLayer[] = pt
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proc setToPreviousLayer*(pt: var LayeredIdTable) {.inline.} =
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when useRef:
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pt = pt.nextLayer
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else:
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when defined(gcDestructors):
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pt = pt.nextLayer[]
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else:
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# workaround refc
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let tmp = pt.nextLayer[]
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pt = tmp
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iterator pairs*(pt: LayeredIdTable): (ItemId, PType) =
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var tm = pt
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while true:
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for (k, v) in idTablePairs(tm.topLayer):
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yield (k, v)
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if tm.nextLayer == nil:
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break
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tm.setToPreviousLayer
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proc lookup(typeMap: ref LayeredIdTableObj, key: ItemId): PType =
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result = nil
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var tm = typeMap
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while tm != nil:
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result = getOrDefault(tm.topLayer, key)
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if result != nil: return
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tm = tm.nextLayer
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template lookup*(typeMap: ref LayeredIdTableObj, key: PType): PType =
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## recursively looks up binding of `key` in all parent layers
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lookup(typeMap, key.itemId)
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when not useRef:
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proc lookup(typeMap: LayeredIdTableObj, key: ItemId): PType {.inline.} =
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result = getOrDefault(typeMap.topLayer, key)
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if result == nil and typeMap.nextLayer != nil:
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result = lookup(typeMap.nextLayer, key)
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template lookup*(typeMap: LayeredIdTableObj, key: PType): PType =
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lookup(typeMap, key.itemId)
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proc put(typeMap: var LayeredIdTable, key: ItemId, value: PType) {.inline.} =
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typeMap.topLayer[key] = value
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template put*(typeMap: var LayeredIdTable, key, value: PType) =
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## binds `key` to `value` only in current layer
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put(typeMap, key.itemId, value)
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