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#
#
# The Nim Compiler
# (c) Copyright 2020 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
proc checkForSink*(config: ConfigRef; idgen: IdGenerator; owner: PSym; arg: PNode) =
#[ Patterns we seek to detect:
someLocation = p # ---> p: sink T
passToSink(p) # p: sink
ObjConstr(fieldName: p)
[p, q] # array construction
# Open question:
var local = p # sink parameter?
passToSink(local)
]#
case arg.kind
of nkSym:
if arg.sym.kind == skParam and
arg.sym.owner == owner and
owner.typ != nil and owner.typ.kind == tyProc and
arg.sym.typ.hasDestructor and
arg.sym.typ.kind notin {tyVar, tySink, tyOwned}:
# Watch out: cannot do this inference for procs with forward
# declarations.
if sfWasForwarded notin owner.flags:
let argType = arg.sym.typ
let sinkType = newType(tySink, idgen, owner)
sinkType.size = argType.size
sinkType.align = argType.align
sinkType.paddingAtEnd = argType.paddingAtEnd
sinkType.add argType
arg.sym.typ = sinkType
owner.typ[arg.sym.position+1] = sinkType
#message(config, arg.info, warnUser,
# ("turned '$1' to a sink parameter") % [$arg])
#echo config $ arg.info, " turned into a sink parameter ", arg.sym.name.s
elif sfWasForwarded notin arg.sym.flags:
# we only report every potential 'sink' parameter only once:
incl arg.sym.flags, sfWasForwarded
message(config, arg.info, hintPerformance,
"could not turn '$1' to a sink parameter" % [arg.sym.name.s])
#echo config $ arg.info, " candidate for a sink parameter here"
of nkStmtList, nkStmtListExpr, nkBlockStmt, nkBlockExpr:
if not isEmptyType(arg.typ):
checkForSink(config, idgen, owner, arg.lastSon)
of nkIfStmt, nkIfExpr, nkWhen:
for branch in arg:
let value = branch.lastSon
if not isEmptyType(value.typ):
checkForSink(config, idgen, owner, value)
of nkCaseStmt:
for i in 1..<arg.len:
let value = arg[i].lastSon
if not isEmptyType(value.typ):
checkForSink(config, idgen, owner, value)
of nkTryStmt:
checkForSink(config, idgen, owner, arg[0])
else:
discard "nothing to do"
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