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#
#
# The Nim Compiler
# (c) Copyright 2015 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## This module implements the '.liftLocals' pragma.
import
intsets, strutils, options, ast, astalgo, msgs,
idents, renderer, types, lowerings
from pragmas import getPragmaVal
from wordrecg import wLiftLocals
type
Ctx = object
partialParam: PSym
objType: PType
proc interestingVar(s: PSym): bool {.inline.} =
result = s.kind in {skVar, skLet, skTemp, skForVar, skResult} and
sfGlobal notin s.flags
proc lookupOrAdd(c: var Ctx; s: PSym; info: TLineInfo): PNode =
let field = addUniqueField(c.objType, s)
var deref = newNodeI(nkHiddenDeref, info)
deref.typ = c.objType
add(deref, newSymNode(c.partialParam, info))
result = newNodeI(nkDotExpr, info)
add(result, deref)
add(result, newSymNode(field))
result.typ = field.typ
proc liftLocals(n: PNode; i: int; c: var Ctx) =
let it = n[i]
case it.kind
of nkSym:
if interestingVar(it.sym):
n[i] = lookupOrAdd(c, it.sym, it.info)
of procDefs, nkTypeSection: discard
else:
for i in 0 ..< it.safeLen:
liftLocals(it, i, c)
proc lookupParam(params, dest: PNode): PSym =
if dest.kind != nkIdent: return nil
for i in 1 ..< params.len:
if params[i].kind == nkSym and params[i].sym.name.id == dest.ident.id:
return params[i].sym
proc liftLocalsIfRequested*(prc: PSym; n: PNode): PNode =
let liftDest = getPragmaVal(prc.ast, wLiftLocals)
if liftDest == nil: return n
let partialParam = lookupParam(prc.typ.n, liftDest)
if partialParam.isNil:
localError(liftDest.info, "'$1' is not a parameter of '$2'" %
[$liftDest, prc.name.s])
return n
let objType = partialParam.typ.skipTypes(abstractPtrs)
if objType.kind != tyObject or tfPartial notin objType.flags:
localError(liftDest.info, "parameter '$1' is not a pointer to a partial object" % $liftDest)
return n
var c = Ctx(partialParam: partialParam, objType: objType)
let w = newTree(nkStmtList, n)
liftLocals(w, 0, c)
result = w[0]
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