added missing file

compiler/liftlocals.nim

@@ -0,0 +1,68 @@
+#
+#
+#           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) =
+  let liftDest = getPragmaVal(prc.ast, wLiftLocals)
+  if liftDest == nil: return
+  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
+  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
+  var c = Ctx(partialParam: partialParam, objType: objType)
+  liftLocals(prc.ast, bodyPos, c)