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Reboot of #16195 (#16746)

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* fix #16185

* fix test

* fix comment

* fix comment

* better approach

* Add more tests and move sameLocation to injectdestructors

* Better and more strict sameLocation

* Small cleanup and preliminary spec clarification

* Fix

* Fix doc

* Expand test

Co-authored-by: Andrey R (cooldome) <ariabushenko@gmail.com>
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Clyybber 2021-01-20 11:05:56 +01:00 • committed by GitHub
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147
compiler/injectdestructors.nim
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@ -968,68 +968,95 @@ proc p(n: PNode; c: var Con; s: var Scope; mode: ProcessMode): PNode =
else:
internalError(c.graph.config, n.info, "cannot inject destructors to node kind: " & $n.kind)
proc moveOrCopy(dest, ri: PNode; c: var Con; s: var Scope, isDecl = false): PNode =
case ri.kind
of nkCallKinds:
result = c.genSink(dest, p(ri, c, s, consumed), isDecl)
of nkBracketExpr:
if isUnpackedTuple(ri[0]):
# unpacking of tuple: take over the elements
result = c.genSink(dest, p(ri, c, s, consumed), isDecl)
elif isAnalysableFieldAccess(ri, c.owner) and isLastRead(ri, c) and
not aliases(dest, ri):
# Rule 3: `=sink`(x, z); wasMoved(z)
var snk = c.genSink(dest, ri, isDecl)
result = newTree(nkStmtList, snk, c.genWasMoved(ri))
else:
result = c.genCopy(dest, ri)
result.add p(ri, c, s, consumed)
c.finishCopy(result, dest, isFromSink = false)
of nkBracket:
# array constructor
if ri.len > 0 and isDangerousSeq(ri.typ):
result = c.genCopy(dest, ri)
result.add p(ri, c, s, consumed)
c.finishCopy(result, dest, isFromSink = false)
else:
result = c.genSink(dest, p(ri, c, s, consumed), isDecl)
of nkObjConstr, nkTupleConstr, nkClosure, nkCharLit..nkNilLit:
result = c.genSink(dest, p(ri, c, s, consumed), isDecl)
of nkSym:
if dest.kind == nkSym and dest.sym == ri.sym:
# rule (self-assignment-removal):
result = newNodeI(nkEmpty, dest.info)
elif isSinkParam(ri.sym) and isLastRead(ri, c):
# Rule 3: `=sink`(x, z); wasMoved(z)
let snk = c.genSink(dest, ri, isDecl)
result = newTree(nkStmtList, snk, c.genWasMoved(ri))
elif ri.sym.kind != skParam and ri.sym.owner == c.owner and
isLastRead(ri, c) and canBeMoved(c, dest.typ) and not isCursor(ri, c):
# Rule 3: `=sink`(x, z); wasMoved(z)
let snk = c.genSink(dest, ri, isDecl)
result = newTree(nkStmtList, snk, c.genWasMoved(ri))
else:
result = c.genCopy(dest, ri)
result.add p(ri, c, s, consumed)
c.finishCopy(result, dest, isFromSink = false)
of nkHiddenSubConv, nkHiddenStdConv, nkConv, nkObjDownConv, nkObjUpConv:
result = c.genSink(dest, p(ri, c, s, sinkArg), isDecl)
of nkStmtListExpr, nkBlockExpr, nkIfExpr, nkCaseStmt, nkTryStmt:
template process(child, s): untyped = moveOrCopy(dest, child, c, s, isDecl)
# We know the result will be a stmt so we use that fact to optimize
handleNestedTempl(ri, process, willProduceStmt = true)
of nkRaiseStmt:
result = pRaiseStmt(ri, c, s)
proc sameLocation*(a, b: PNode): bool =
proc sameConstant(a, b: PNode): bool =
a.kind in nkLiterals and exprStructuralEquivalent(a, b)
const nkEndPoint = {nkSym, nkDotExpr, nkCheckedFieldExpr, nkBracketExpr}
if a.kind in nkEndPoint and b.kind in nkEndPoint:
if a.kind == b.kind:
case a.kind
of nkSym: a.sym == b.sym
of nkDotExpr, nkCheckedFieldExpr: sameLocation(a[0], b[0]) and sameLocation(a[1], b[1])
of nkBracketExpr: sameLocation(a[0], b[0]) and sameConstant(a[1], b[1])
else: false
else: false
else:
if isAnalysableFieldAccess(ri, c.owner) and isLastRead(ri, c) and
canBeMoved(c, dest.typ):
# Rule 3: `=sink`(x, z); wasMoved(z)
let snk = c.genSink(dest, ri, isDecl)
result = newTree(nkStmtList, snk, c.genWasMoved(ri))
case a.kind
of nkSym, nkDotExpr, nkCheckedFieldExpr, nkBracketExpr:
# Reached an endpoint, flip to recurse the other side.
sameLocation(b, a)
of nkAddr, nkHiddenAddr, nkDerefExpr, nkHiddenDeref:
# We don't need to check addr/deref levels or differentiate between the two,
# since pointers don't have hooks :) (e.g: var p: ptr pointer; p[] = addr p)
sameLocation(a[0], b)
of nkObjDownConv, nkObjUpConv: sameLocation(a[0], b)
of nkHiddenStdConv, nkHiddenSubConv: sameLocation(a[1], b)
else: false
proc moveOrCopy(dest, ri: PNode; c: var Con; s: var Scope, isDecl = false): PNode =
if sameLocation(dest, ri):
# rule (self-assignment-removal):
result = newNodeI(nkEmpty, dest.info)
else:
case ri.kind
of nkCallKinds:
result = c.genSink(dest, p(ri, c, s, consumed), isDecl)
of nkBracketExpr:
if isUnpackedTuple(ri[0]):
# unpacking of tuple: take over the elements
result = c.genSink(dest, p(ri, c, s, consumed), isDecl)
elif isAnalysableFieldAccess(ri, c.owner) and isLastRead(ri, c) and
not aliases(dest, ri):
# Rule 3: `=sink`(x, z); wasMoved(z)
var snk = c.genSink(dest, ri, isDecl)
result = newTree(nkStmtList, snk, c.genWasMoved(ri))
else:
result = c.genCopy(dest, ri)
result.add p(ri, c, s, consumed)
c.finishCopy(result, dest, isFromSink = false)
of nkBracket:
# array constructor
if ri.len > 0 and isDangerousSeq(ri.typ):
result = c.genCopy(dest, ri)
result.add p(ri, c, s, consumed)
c.finishCopy(result, dest, isFromSink = false)
else:
result = c.genSink(dest, p(ri, c, s, consumed), isDecl)
of nkObjConstr, nkTupleConstr, nkClosure, nkCharLit..nkNilLit:
result = c.genSink(dest, p(ri, c, s, consumed), isDecl)
of nkSym:
if isSinkParam(ri.sym) and isLastRead(ri, c):
# Rule 3: `=sink`(x, z); wasMoved(z)
let snk = c.genSink(dest, ri, isDecl)
result = newTree(nkStmtList, snk, c.genWasMoved(ri))
elif ri.sym.kind != skParam and ri.sym.owner == c.owner and
isLastRead(ri, c) and canBeMoved(c, dest.typ) and not isCursor(ri, c):
# Rule 3: `=sink`(x, z); wasMoved(z)
let snk = c.genSink(dest, ri, isDecl)
result = newTree(nkStmtList, snk, c.genWasMoved(ri))
else:
result = c.genCopy(dest, ri)
result.add p(ri, c, s, consumed)
c.finishCopy(result, dest, isFromSink = false)
of nkHiddenSubConv, nkHiddenStdConv, nkConv, nkObjDownConv, nkObjUpConv:
result = c.genSink(dest, p(ri, c, s, sinkArg), isDecl)
of nkStmtListExpr, nkBlockExpr, nkIfExpr, nkCaseStmt, nkTryStmt:
template process(child, s): untyped = moveOrCopy(dest, child, c, s, isDecl)
# We know the result will be a stmt so we use that fact to optimize
handleNestedTempl(ri, process, willProduceStmt = true)
of nkRaiseStmt:
result = pRaiseStmt(ri, c, s)
else:
result = c.genCopy(dest, ri)
result.add p(ri, c, s, consumed)
c.finishCopy(result, dest, isFromSink = false)
if isAnalysableFieldAccess(ri, c.owner) and isLastRead(ri, c) and
canBeMoved(c, dest.typ):
# Rule 3: `=sink`(x, z); wasMoved(z)
let snk = c.genSink(dest, ri, isDecl)
result = newTree(nkStmtList, snk, c.genWasMoved(ri))
else:
result = c.genCopy(dest, ri)
result.add p(ri, c, s, consumed)
c.finishCopy(result, dest, isFromSink = false)
proc computeUninit(c: var Con) =
if not c.uninitComputed: