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Implements RFCs #209 (#13995)

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* add test
* add changelod entry
Co-authored-by: cooldome <ariabushenko@bk.ru>
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cooldome 2020-04-16 20:04:05 +01:00 • committed by GitHub
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9 changed files with 292 additions and 108 deletions
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73
compiler/injectdestructors.nim
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@ -22,9 +22,9 @@
# - eliminate 'wasMoved(x); destroy(x)' pairs as a post processing step.
import
intsets, ast, msgs, renderer, magicsys, types, idents,
intsets, ast, astalgo, msgs, renderer, magicsys, types, idents,
strutils, options, dfa, lowerings, tables, modulegraphs, msgs,
lineinfos, parampatterns, sighashes
lineinfos, parampatterns, sighashes, liftdestructors
from trees import exprStructuralEquivalent
from algorithm import reverse
@ -49,6 +49,12 @@ type
uninit: IntSet # set of uninit'ed vars
uninitComputed: bool
ProcessMode = enum
normal
consumed
sinkArg
const toDebug {.strdefine.} = ""
template dbg(body) =
@ -56,6 +62,9 @@ template dbg(body) =
if c.owner.name.s == toDebug or toDebug == "always":
body
proc p(n: PNode; c: var Con; mode: ProcessMode): PNode
proc moveOrCopy(dest, ri: PNode; c: var Con): PNode
proc isLastRead(location: PNode; c: var Con; pc, comesFrom: int): int =
var pc = pc
while pc < c.g.len:
@ -220,16 +229,19 @@ proc makePtrType(c: Con, baseType: PType): PType =
result = newType(tyPtr, c.owner)
addSonSkipIntLit(result, baseType)
proc genOp(c: Con; op: PSym; dest: PNode): PNode =
let addrExp = newNodeIT(nkHiddenAddr, dest.info, makePtrType(c, dest.typ))
addrExp.add(dest)
result = newTree(nkCall, newSymNode(op), addrExp)
proc genOp(c: Con; t: PType; kind: TTypeAttachedOp; dest, ri: PNode): PNode =
var op = t.attachedOps[kind]
if op == nil or op.ast[genericParamsPos].kind != nkEmpty:
# give up and find the canonical type instead:
let h = sighashes.hashType(t, {CoType, CoConsiderOwned, CoDistinct})
let canon = c.graph.canonTypes.getOrDefault(h)
if canon != nil:
op = canon.attachedOps[kind]
if op == nil:
#echo dest.typ.id
globalError(c.graph.config, dest.info, "internal error: '" & AttachedOpToStr[kind] &
@ -241,9 +253,7 @@ proc genOp(c: Con; t: PType; kind: TTypeAttachedOp; dest, ri: PNode): PNode =
if kind == attachedDestructor:
echo "destructor is ", op.id, " ", op.ast
if sfError in op.flags: checkForErrorPragma(c, t, ri, AttachedOpToStr[kind])
let addrExp = newNodeIT(nkHiddenAddr, dest.info, makePtrType(c, dest.typ))
addrExp.add(dest)
result = newTree(nkCall, newSymNode(op), addrExp)
genOp(c, op, dest)
proc genDestroy(c: Con; dest: PNode): PNode =
let t = dest.typ.skipTypes({tyGenericInst, tyAlias, tySink})
@ -300,6 +310,44 @@ proc getTemp(c: var Con; typ: PType; info: TLineInfo): PNode =
sym.typ = typ
result = newSymNode(sym)
proc genDiscriminantAsgn(c: var Con; n: PNode): PNode =
# discriminator is ordinal value that doesn't need sink destroy
# but fields within active case branch might need destruction
# tmp to support self assignments
let tmp = getTemp(c, n[1].typ, n.info)
c.addTopVar(tmp)
result = newTree(nkStmtList)
result.add newTree(nkFastAsgn, tmp, p(n[1], c, consumed))
result.add p(n[0], c, normal)
let le = p(n[0], c, normal)
let leDotExpr = if le.kind == nkCheckedFieldExpr: le[0] else: le
let objType = leDotExpr[0].typ
if hasDestructor(objType):
if objType.attachedOps[attachedDestructor] != nil and
sfOverriden in objType.attachedOps[attachedDestructor].flags:
localError(c.graph.config, n.info, errGenerated, """Assignment to discriminant for object's with user defined destructor is not supported, object must have default destructor.
It is best to factor out piece of object that needs custom destructor into separate object or not use discriminator assignment""")
result.add newTree(nkFastAsgn, le, tmp)
return
# generate: if le != tmp: `=destroy`(le)
let branchDestructor = produceDestructorForDiscriminator(c.graph, objType, leDotExpr[1].sym, n.info)
let cond = newNodeIT(nkInfix, n.info, getSysType(c.graph, unknownLineInfo, tyBool))
cond.add newSymNode(getMagicEqSymForType(c.graph, le.typ, n.info))
cond.add le
cond.add tmp
let notExpr = newNodeIT(nkPrefix, n.info, getSysType(c.graph, unknownLineInfo, tyBool))
notExpr.add newSymNode(createMagic(c.graph, "not", mNot))
notExpr.add cond
result.add newTree(nkIfStmt, newTree(nkElifBranch, notExpr, genOp(c, branchDestructor, le)))
result.add newTree(nkFastAsgn, le, tmp)
else:
result.add newTree(nkFastAsgn, le, tmp)
proc genWasMoved(n: PNode; c: var Con): PNode =
result = newNodeI(nkCall, n.info)
result.add(newSymNode(createMagic(c.graph, "wasMoved", mWasMoved)))
@ -338,15 +386,6 @@ proc sinkParamIsLastReadCheck(c: var Con, s: PNode) =
localError(c.graph.config, c.otherRead.info, "sink parameter `" & $s.sym.name.s &
"` is already consumed at " & toFileLineCol(c. graph.config, s.info))
type
ProcessMode = enum
normal
consumed
sinkArg
proc p(n: PNode; c: var Con; mode: ProcessMode): PNode
proc moveOrCopy(dest, ri: PNode; c: var Con): PNode
proc isClosureEnv(n: PNode): bool = n.kind == nkSym and n.sym.name.s[0] == ':'
proc passCopyToSink(n: PNode; c: var Con): PNode =
@ -867,6 +906,8 @@ proc p(n: PNode; c: var Con; mode: ProcessMode): PNode =
cycleCheck(n, c)
assert n[1].kind notin {nkAsgn, nkFastAsgn}
result = moveOrCopy(p(n[0], c, mode), n[1], c)
elif isDiscriminantField(n[0]):
result = genDiscriminantAsgn(c, n)
else:
result = copyNode(n)
result.add p(n[0], c, mode)