#
#
#           The Nim Compiler
#        (c) Copyright 2015 Andreas Rumpf
#
#    See the file "copying.txt", included in this
#    distribution, for details about the copyright.
#

import
  intsets, ast, astalgo, msgs, renderer, magicsys, types, idents, trees,
  wordrecg, strutils, options, guards, lineinfos, semfold,
  modulegraphs

when not defined(leanCompiler):
  import writetracking

when defined(useDfa):
  import dfa

# Second semantic checking pass over the AST. Necessary because the old
# way had some inherent problems. Performs:
#
# * effect+exception tracking
# * "usage before definition" checking

# ------------------------ exception and tag tracking -------------------------

discard """
  exception tracking:

  a() # raises 'x', 'e'
  try:
    b() # raises 'e'
  except e:
    # must not undo 'e' here; hrm
    c()

 --> we need a stack of scopes for this analysis

  # XXX enhance the algorithm to care about 'dirty' expressions:
  lock a[i].L:
    inc i # mark 'i' dirty
    lock a[j].L:
      access a[i], a[j]  # --> reject a[i]
"""

type
  TEffects = object
    exc: PNode  # stack of exceptions
    tags: PNode # list of tags
    bottom, inTryStmt: int
    owner: PSym
    owner_module: PSym
    init: seq[int] # list of initialized variables
    guards: TModel # nested guards
    locked: seq[PNode] # locked locations
    gcUnsafe, isRecursive, isToplevel, hasSideEffect, inEnforcedGcSafe: bool
    inEnforcedNoSideEffects: bool
    maxLockLevel, currLockLevel: TLockLevel
    config: ConfigRef
    graph: ModuleGraph
  PEffects = var TEffects

proc `<`(a, b: TLockLevel): bool {.borrow.}
proc `<=`(a, b: TLockLevel): bool {.borrow.}
proc `==`(a, b: TLockLevel): bool {.borrow.}
proc max(a, b: TLockLevel): TLockLevel {.borrow.}

proc isLocalVar(a: PEffects, s: PSym): bool =
  s.kind in {skVar, skResult} and sfGlobal notin s.flags and
    s.owner == a.owner and s.typ != nil

proc getLockLevel(t: PType): TLockLevel =
  var t = t
  # tyGenericInst(TLock {tyGenericBody}, tyStatic, tyObject):
  if t.kind == tyGenericInst and t.len == 3: t = t.sons[1]
  if t.kind == tyStatic and t.n != nil and t.n.kind in {nkCharLit..nkInt64Lit}:
    result = t.n.intVal.TLockLevel

proc lockLocations(a: PEffects; pragma: PNode) =
  if pragma.kind != nkExprColonExpr:
    localError(a.config, pragma.info, "locks pragma without argument")
    return
  var firstLL = TLockLevel(-1'i16)
  for x in pragma[1]:
    let thisLL = getLockLevel(x.typ)
    if thisLL != 0.TLockLevel:
      if thisLL < 0.TLockLevel or thisLL > MaxLockLevel.TLockLevel:
        localError(a.config, x.info, "invalid lock level: " & $thisLL)
      elif firstLL < 0.TLockLevel: firstLL = thisLL
      elif firstLL != thisLL:
        localError(a.config, x.info,
          "multi-lock requires the same static lock level for every operand")
      a.maxLockLevel = max(a.maxLockLevel, firstLL)
    a.locked.add x
  if firstLL >= 0.TLockLevel and firstLL != a.currLockLevel:
    if a.currLockLevel > 0.TLockLevel and a.currLockLevel <= firstLL:
      localError(a.config, pragma.info, "invalid nested locking")
    a.currLockLevel = firstLL

proc guardGlobal(a: PEffects; n: PNode; guard: PSym) =
  # check whether the corresponding lock is held:
  for L in a.locked:
    if L.kind == nkSym and L.sym == guard: return
  # we allow accesses nevertheless in top level statements for
  # easier initialization:
  #if a.isTopLevel:
  #  message(n.info, warnUnguardedAccess, renderTree(n))
  #else:
  if not a.isTopLevel:
    localError(a.config, n.info, "unguarded access: " & renderTree(n))

# 'guard*' are checks which are concerned with 'guard' annotations
# (var x{.guard: y.}: int)
proc guardDotAccess(a: PEffects; n: PNode) =
  let ri = n.sons[1]
  if ri.kind != nkSym or ri.sym.kind != skField: return
  var g = ri.sym.guard
  if g.isNil or a.isTopLevel: return
  # fixup guard:
  if g.kind == skUnknown:
    var field: PSym = nil
    var ty = n.sons[0].typ.skipTypes(abstractPtrs)
    if ty.kind == tyTuple and not ty.n.isNil:
      field = lookupInRecord(ty.n, g.name)
    else:
      while ty != nil and ty.kind == tyObject:
        field = lookupInRecord(ty.n, g.name)
        if field != nil: break
        ty = ty.sons[0]
        if ty == nil: break
        ty = ty.skipTypes(skipPtrs)
    if field == nil:
      localError(a.config, n.info, "invalid guard field: " & g.name.s)
      return
    g = field
    #ri.sym.guard = field
    # XXX unfortunately this is not correct for generic instantiations!
  if g.kind == skField:
    let dot = newNodeI(nkDotExpr, n.info, 2)
    dot.sons[0] = n.sons[0]
    dot.sons[1] = newSymNode(g)
    dot.typ = g.typ
    for L in a.locked:
      #if a.guards.sameSubexprs(dot, L): return
      if guards.sameTree(dot, L): return
    localError(a.config, n.info, "unguarded access: " & renderTree(n))
  else:
    guardGlobal(a, n, g)

proc makeVolatile(a: PEffects; s: PSym) {.inline.} =
  template compileToCpp(a): untyped =
    a.config.cmd == cmdCompileToCpp or sfCompileToCpp in getModule(a.owner).flags
  if a.inTryStmt > 0 and not compileToCpp(a):
    incl(s.flags, sfVolatile)

proc initVar(a: PEffects, n: PNode; volatileCheck: bool) =
  if n.kind != nkSym: return
  let s = n.sym
  if isLocalVar(a, s):
    if volatileCheck: makeVolatile(a, s)
    for x in a.init:
      if x == s.id: return
    a.init.add s.id

proc initVarViaNew(a: PEffects, n: PNode) =
  if n.kind != nkSym: return
  let s = n.sym
  if {tfNeedsInit, tfNotNil} * s.typ.flags <= {tfNotNil}:
    # 'x' is not nil, but that doesn't mean its "not nil" children
    # are initialized:
    initVar(a, n, volatileCheck=true)
  elif isLocalVar(a, s):
    makeVolatile(a, s)

proc warnAboutGcUnsafe(n: PNode; conf: ConfigRef) =
  #assert false
  message(conf, n.info, warnGcUnsafe, renderTree(n))

proc markGcUnsafe(a: PEffects; reason: PSym) =
  if not a.inEnforcedGcSafe:
    a.gcUnsafe = true
    if a.owner.kind in routineKinds: a.owner.gcUnsafetyReason = reason

proc markGcUnsafe(a: PEffects; reason: PNode) =
  if not a.inEnforcedGcSafe:
    a.gcUnsafe = true
    if a.owner.kind in routineKinds:
      if reason.kind == nkSym:
        a.owner.gcUnsafetyReason = reason.sym
      else:
        a.owner.gcUnsafetyReason = newSym(skUnknown, a.owner.name,
                                          a.owner, reason.info, {})

when true:
  template markSideEffect(a: PEffects; reason: typed) =
    if not a.inEnforcedNoSideEffects: a.hasSideEffect = true
else:
  template markSideEffect(a: PEffects; reason: typed) =
    if not a.inEnforcedNoSideEffects: a.hasSideEffect = true
    markGcUnsafe(a, reason)

proc listGcUnsafety(s: PSym; onlyWarning: bool; cycleCheck: var IntSet; conf: ConfigRef) =
  let u = s.gcUnsafetyReason
  if u != nil and not cycleCheck.containsOrIncl(u.id):
    let msgKind = if onlyWarning: warnGcUnsafe2 else: errGenerated
    case u.kind
    of skLet, skVar:
      message(conf, s.info, msgKind,
        ("'$#' is not GC-safe as it accesses '$#'" &
        " which is a global using GC'ed memory") % [s.name.s, u.name.s])
    of routineKinds:
      # recursive call *always* produces only a warning so the full error
      # message is printed:
      listGcUnsafety(u, true, cycleCheck, conf)
      message(conf, s.info, msgKind,
        "'$#' is not GC-safe as it calls '$#'" %
        [s.name.s, u.name.s])
    of skParam, skForVar:
      message(conf, s.info, msgKind,
        "'$#' is not GC-safe as it performs an indirect call via '$#'" %
        [s.name.s, u.name.s])
    else:
      message(conf, u.info, msgKind,
        "'$#' is not GC-safe as it performs an indirect call here" % s.name.s)

proc listGcUnsafety(s: PSym; onlyWarning: bool; conf: ConfigRef) =
  var cycleCheck = initIntSet()
  listGcUnsafety(s, onlyWarning, cycleCheck, conf)

proc useVar(a: PEffects, n: PNode) =
  let s = n.sym
  if isLocalVar(a, s):
    if s.id notin a.init:
      if {tfNeedsInit, tfNotNil} * s.typ.flags != {}:
        message(a.config, n.info, warnProveInit, s.name.s)
      else:
        message(a.config, n.info, warnUninit, s.name.s)
      # prevent superfluous warnings about the same variable:
      a.init.add s.id
  if {sfGlobal, sfThread} * s.flags != {} and s.kind in {skVar, skLet} and
      s.magic != mNimVm:
    if s.guard != nil: guardGlobal(a, n, s.guard)
    if {sfGlobal, sfThread} * s.flags == {sfGlobal} and
        (tfHasGCedMem in s.typ.flags or s.typ.isGCedMem):
      #if warnGcUnsafe in gNotes: warnAboutGcUnsafe(n)
      markGcUnsafe(a, s)
      markSideEffect(a, s)
    else:
      markSideEffect(a, s)


type
  TIntersection = seq[tuple[id, count: int]] # a simple count table

proc addToIntersection(inter: var TIntersection, s: int) =
  for j in 0..<inter.len:
    if s == inter[j].id:
      inc inter[j].count
      return
  inter.add((id: s, count: 1))

proc throws(tracked, n: PNode) =
  if n.typ == nil or n.typ.kind != tyError: tracked.add n

proc getEbase(g: ModuleGraph; info: TLineInfo): PType =
  result = g.sysTypeFromName(info, "Exception")

proc excType(g: ModuleGraph; n: PNode): PType =
  # reraise is like raising E_Base:
  let t = if n.kind == nkEmpty or n.typ.isNil: getEbase(g, n.info) else: n.typ
  result = skipTypes(t, skipPtrs)

proc createRaise(g: ModuleGraph; n: PNode): PNode =
  result = newNode(nkType)
  result.typ = getEbase(g, n.info)
  if not n.isNil: result.info = n.info

proc createTag(g: ModuleGraph; n: PNode): PNode =
  result = newNode(nkType)
  result.typ = g.sysTypeFromName(n.info, "RootEffect")
  if not n.isNil: result.info = n.info

proc addEffect(a: PEffects, e: PNode, useLineInfo=true) =
  assert e.kind != nkRaiseStmt
  var aa = a.exc
  for i in a.bottom ..< aa.len:
    if sameType(a.graph.excType(aa[i]), a.graph.excType(e)):
      if not useLineInfo or a.config.cmd == cmdDoc: return
      elif aa[i].info == e.info: return
  throws(a.exc, e)

proc addTag(a: PEffects, e: PNode, useLineInfo=true) =
  var aa = a.tags
  for i in 0 ..< aa.len:
    if sameType(aa[i].typ.skipTypes(skipPtrs), e.typ.skipTypes(skipPtrs)):
      if not useLineInfo or a.config.cmd == cmdDoc: return
      elif aa[i].info == e.info: return
  throws(a.tags, e)

proc mergeEffects(a: PEffects, b, comesFrom: PNode) =
  if b.isNil:
    addEffect(a, createRaise(a.graph, comesFrom))
  else:
    for effect in items(b): addEffect(a, effect, useLineInfo=comesFrom != nil)

proc mergeTags(a: PEffects, b, comesFrom: PNode) =
  if b.isNil:
    addTag(a, createTag(a.graph, comesFrom))
  else:
    for effect in items(b): addTag(a, effect, useLineInfo=comesFrom != nil)

proc listEffects(a: PEffects) =
  for e in items(a.exc):  message(a.config, e.info, hintUser, typeToString(e.typ))
  for e in items(a.tags): message(a.config, e.info, hintUser, typeToString(e.typ))
  #if a.maxLockLevel != 0:
  #  message(e.info, hintUser, "lockLevel: " & a.maxLockLevel)

proc catches(tracked: PEffects, e: PType) =
  let e = skipTypes(e, skipPtrs)
  var L = tracked.exc.len
  var i = tracked.bottom
  while i < L:
    # r supertype of e?
    if safeInheritanceDiff(tracked.graph.excType(tracked.exc[i]), e) <= 0:
      tracked.exc.sons[i] = tracked.exc.sons[L-1]
      dec L
    else:
      inc i
  if tracked.exc.len > 0:
    setLen(tracked.exc.sons, L)
  else:
    assert L == 0

proc catchesAll(tracked: PEffects) =
  if tracked.exc.len > 0:
    setLen(tracked.exc.sons, tracked.bottom)

proc track(tracked: PEffects, n: PNode)
proc trackTryStmt(tracked: PEffects, n: PNode) =
  let oldBottom = tracked.bottom
  tracked.bottom = tracked.exc.len

  let oldState = tracked.init.len
  var inter: TIntersection = @[]

  inc tracked.inTryStmt
  track(tracked, n.sons[0])
  dec tracked.inTryStmt
  for i in oldState..<tracked.init.len:
    addToIntersection(inter, tracked.init[i])

  var branches = 1
  var hasFinally = false
  for i in 1 ..< n.len:
    let b = n.sons[i]
    let blen = sonsLen(b)
    if b.kind == nkExceptBranch:
      inc branches
      if blen == 1:
        catchesAll(tracked)
      else:
        for j in countup(0, blen - 2):
          if b.sons[j].isInfixAs():
            assert(b.sons[j][1].kind == nkType)
            catches(tracked, b.sons[j][1].typ)
          else:
            assert(b.sons[j].kind == nkType)
            catches(tracked, b.sons[j].typ)
      setLen(tracked.init, oldState)
      track(tracked, b.sons[blen-1])
      for i in oldState..<tracked.init.len:
        addToIntersection(inter, tracked.init[i])
    else:
      assert b.kind == nkFinally
      setLen(tracked.init, oldState)
      track(tracked, b.sons[blen-1])
      hasFinally = true

  tracked.bottom = oldBottom
  if not hasFinally:
    setLen(tracked.init, oldState)
  for id, count in items(inter):
    if count == branches: tracked.init.add id

proc isIndirectCall(n: PNode, owner: PSym): bool =
  # we don't count f(...) as an indirect call if 'f' is an parameter.
  # Instead we track expressions of type tyProc too. See the manual for
  # details:
  if n.kind != nkSym:
    result = true
  elif n.sym.kind == skParam:
    result = owner != n.sym.owner or owner == nil
  elif n.sym.kind notin routineKinds:
    result = true

proc isForwardedProc(n: PNode): bool =
  result = n.kind == nkSym and sfForward in n.sym.flags

proc trackPragmaStmt(tracked: PEffects, n: PNode) =
  for i in countup(0, sonsLen(n) - 1):
    var it = n.sons[i]
    if whichPragma(it) == wEffects:
      # list the computed effects up to here:
      listEffects(tracked)

proc effectSpec(n: PNode, effectType: TSpecialWord): PNode =
  for i in countup(0, sonsLen(n) - 1):
    var it = n.sons[i]
    if it.kind == nkExprColonExpr and whichPragma(it) == effectType:
      result = it.sons[1]
      if result.kind notin {nkCurly, nkBracket}:
        result = newNodeI(nkCurly, result.info)
        result.add(it.sons[1])
      return

proc documentEffect(cache: IdentCache; n, x: PNode, effectType: TSpecialWord, idx: int): PNode =
  let spec = effectSpec(x, effectType)
  if isNil(spec):
    let s = n.sons[namePos].sym

    let actual = s.typ.n.sons[0]
    if actual.len != effectListLen: return
    let real = actual.sons[idx]

    # warning: hack ahead:
    var effects = newNodeI(nkBracket, n.info, real.len)
    for i in 0 ..< real.len:
      var t = typeToString(real[i].typ)
      if t.startsWith("ref "): t = substr(t, 4)
      effects.sons[i] = newIdentNode(getIdent(cache, t), n.info)
      # set the type so that the following analysis doesn't screw up:
      effects.sons[i].typ = real[i].typ

    result = newNode(nkExprColonExpr, n.info, @[
      newIdentNode(getIdent(cache, specialWords[effectType]), n.info), effects])

proc documentWriteEffect(cache: IdentCache; n: PNode; flag: TSymFlag; pragmaName: string): PNode =
  let s = n.sons[namePos].sym
  let params = s.typ.n

  var effects = newNodeI(nkBracket, n.info)
  for i in 1 ..< params.len:
    if params[i].kind == nkSym and flag in params[i].sym.flags:
      effects.add params[i]

  if effects.len > 0:
    result = newNode(nkExprColonExpr, n.info, @[
      newIdentNode(getIdent(cache, pragmaName), n.info), effects])

proc documentNewEffect(cache: IdentCache; n: PNode): PNode =
  let s = n.sons[namePos].sym
  if tfReturnsNew in s.typ.flags:
    result = newIdentNode(getIdent(cache, "new"), n.info)

proc documentRaises*(cache: IdentCache; n: PNode) =
  if n.sons[namePos].kind != nkSym: return
  let pragmas = n.sons[pragmasPos]
  let p1 = documentEffect(cache, n, pragmas, wRaises, exceptionEffects)
  let p2 = documentEffect(cache, n, pragmas, wTags, tagEffects)
  let p3 = documentWriteEffect(cache, n, sfWrittenTo, "writes")
  let p4 = documentNewEffect(cache, n)
  let p5 = documentWriteEffect(cache, n, sfEscapes, "escapes")

  if p1 != nil or p2 != nil or p3 != nil or p4 != nil or p5 != nil:
    if pragmas.kind == nkEmpty:
      n.sons[pragmasPos] = ne<style>pre { line-height: 125%; }
td.linenos .normal { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
span.linenos { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */
.highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */
.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
.highlight .kp { color: #008800 } /* Keyword.Pseudo */
.highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */
.highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */
.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */
.highlight .no { color: #003366; font-weight: bold } /* Name.Constant */
.highlight .nd { color: #555555 } /* Name.Decorator */
.highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */
.highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */
.highlight .nl { color: #336699; font-style: italic } /* Name.Label */
.highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */
.highlight .py { color: #336699; font-weight: bold } /* Name.Property */
.highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */
.highlight .nv { color: #336699 } /* Name.Variable */
.highlight .ow { color: #008800 } /* Operator.Word */
.highlight .w { color: #bbbbbb } /* Text.Whitespace */
.highlight .mb { color: #0000DD; font-weight: bold } /* Literal.Number.Bin */
.highlight .mf { color: #0000DD; font-weight: bold } /* Literal.Number.Float */
.highlight .mh { color: #0000DD; font-weight: bold } /* Literal.Number.Hex */
.highlight .mi { color: #0000DD; font-weight: bold } /* Literal.Number.Integer */
.highlight .mo { color: #0000DD; font-weight: bold } /* Literal.Number.Oct */
.highlight .sa { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Affix */
.highlight .sb { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Backtick */
.highlight .sc { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Char */
.highlight .dl { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Delimiter */
.highlight .sd { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Doc */
.highlight .s2 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Double */
.highlight .se { color: #0044dd; background-color: #fff0f0 } /* Literal.String.Escape */
.highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */
.highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */
.highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */
.highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */
.highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */
.highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */
.highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */
.highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */
.highlight .vc { color: #336699 } /* Name.Variable.Class */
.highlight .vg { color: #dd7700 } /* Name.Variable.Global */
.highlight .vi { color: #3333bb } /* Name.Variable.Instance */
.highlight .vm { color: #336699 } /* Name.Variable.Magic */
.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */</style><div class="highlight"><pre><span></span>LIBRARY<span class="w"> </span>gdi32.dll

EXPORTS
AbortDoc
AbortPath
AddFontResourceA
AddFontResourceW
AngleArc
AnimatePalette
Arc
ArcTo
BeginPath
BitBlt
ByeByeGDI
CancelDC
CheckColorsInGamut
ChoosePixelFormat
Chord
CloseEnhMetaFile
CloseFigure
CloseMetaFile
ColorCorrectPalette
ColorMatchToTarget
CombineRgn
CombineTransform
CopyEnhMetaFileA
CopyEnhMetaFileW
CopyMetaFileA
CopyMetaFileW
CreateBitmap
CreateBitmapIndirect
CreateBrushIndirect
CreateColorSpaceA
CreateColorSpaceW
CreateCompatibleBitmap
CreateCompatibleDC
CreateDCA
CreateDCW
CreateDIBPatternBrush
CreateDIBPatternBrushPt
CreateDIBSection
CreateDIBitmap
CreateDiscardableBitmap
CreateEllipticRgn
CreateEllipticRgnIndirect
CreateEnhMetaFileA
CreateEnhMetaFileW
CreateFontA
CreateFontIndirectA
CreateFontIndirectW
CreateFontW
CreateHalftonePalette
CreateHatchBrush
CreateICA
CreateICW
CreateMetaFileA
CreateMetaFileW
CreatePalette
CreatePatternBrush
CreatePen
CreatePenIndirect
CreatePolyPolygonRgn
CreatePolygonRgn
CreateRectRgn
CreateRectRgnIndirect
CreateRoundRectRgn
CreateScalableFontResourceA
CreateScalableFontResourceW
CreateSolidBrush
DPtoLP
DeleteColorSpace
DeleteDC
DeleteEnhMetaFile
DeleteMetaFile
DeleteObject
DescribePixelFormat
DeviceCapabilitiesEx
DeviceCapabilitiesExA
DeviceCapabilitiesExW
DrawEscape
Ellipse
EnableEUDC
EndDoc
EndPage
EndPath
EnumEnhMetaFile
EnumFontFamiliesA
EnumFontFamiliesExA
EnumFontFamiliesExW
EnumFontFamiliesW
EnumFontsA
EnumFontsW
EnumICMProfilesA
EnumICMProfilesW
EnumMetaFile
EnumObjects
EqualRgn
Escape
ExcludeClipRect
ExtCreatePen
ExtCreateRegion
ExtEscape
ExtFloodFill
ExtSelectClipRgn
ExtTextOutA
ExtTextOutW
FillPath
FillRgn
FixBrushOrgEx
FlattenPath
FloodFill
FrameRgn
GdiComment
GdiFlush
GdiGetBatchLimit
GdiPlayDCScript
GdiPlayJournal
GdiPlayScript
GdiSetBatchLimit
GetArcDirection
GetAspectRatioFilterEx
GetBitmapBits
GetBitmapDimensionEx
GetBkColor
GetBkMode
GetBoundsRect
GetBrushOrgEx
GetCharABCWidthsA
GetCharABCWidthsFloatA
GetCharABCWidthsFloatW
GetCharABCWidthsW
GetCharWidth32A
GetCharWidth32W
GetCharWidthA
GetCharWidthFloatA
GetCharWidthFloatW
GetCharWidthW
GetCharacterPlacementA
GetCharacterPlacementW
GetClipBox
GetClipRgn
GetColorAdjustment
GetColorSpace
GetCurrentObject
GetCurrentPositionEx
GetDCOrgEx
GetDIBColorTable
GetDIBits
GetDeviceCaps
GetDeviceGammaRamp
GetEnhMetaFileA
GetEnhMetaFileBits
GetEnhMetaFileDescriptionA
GetEnhMetaFileDescriptionW
GetEnhMetaFileHeader
GetEnhMetaFilePaletteEntries
GetEnhMetaFileW
GetFontData
GetFontLanguageInfo
GetFontResourceInfo
GetGlyphOutline
GetGlyphOutlineA
GetGlyphOutlineW
GetGraphicsMode
GetICMProfileA
GetICMProfileW
GetKerningPairs
GetKerningPairsA
GetKerningPairsW
GetLayout
GetLogColorSpaceA
GetLogColorSpaceW
GetMapMode
GetMetaFileA
GetMetaFileBitsEx
GetMetaFileW
GetMetaRgn
GetMiterLimit
GetNearestColor
GetNearestPaletteIndex
GetObjectA
GetObjectType
GetObjectW
GetOutlineTextMetricsA
GetOutlineTextMetricsW
GetPaletteEntries
GetPath
GetPixel
GetPixelFormat
GetPolyFillMode
GetROP2
GetRandomRgn
GetRasterizerCaps
GetRegionData
GetRgnBox
GetStockObject
GetStretchBltMode
GetSystemPaletteEntries
GetSystemPaletteUse
GetTextAlign
GetTextCharacterExtra
GetTextCharset
GetTextCharsetInfo
GetTextColor
GetTextExtentExPointA
GetTextExtentExPointW
GetTextExtentPoint32A
GetTextExtentPoint32W
GetTextExtentPointA
GetTextExtentPointW
GetTextFaceA
GetTextFaceW
GetTextMetricsA
GetTextMetricsW
GetViewportExtEx
GetViewportOrgEx
GetWinMetaFileBits
GetWindowExtEx
GetWindowOrgEx
GetWorldTransform
IntersectClipRect
InvertRgn
LPtoDP
LineDDA
LineTo
MaskBlt
ModifyWorldTransform
MoveToEx
OffsetClipRgn
OffsetRgn
OffsetViewportOrgEx
OffsetWindowOrgEx
PaintRgn
PatBlt
PathToRegion
Pie
PlayEnhMetaFile
PlayEnhMetaFileRecord
PlayMetaFile
PlayMetaFileRecord
PlgBlt
PolyBezier
PolyBezierTo
PolyDraw
PolyPolygon
PolyPolyline
PolyTextOutA
PolyTextOutW
Polygon
Polyline
PolylineTo
PtInRegion
PtVisible
RealizePalette
RectInRegion
RectVisible
Rectangle
RemoveFontResourceA
RemoveFontResourceW
ResetDCA
ResetDCW
ResizePalette
RestoreDC
RoundRect
SaveDC
ScaleViewportExtEx
ScaleWindowExtEx
SelectClipPath
SelectClipRgn
SelectObject
SelectPalette
SetAbortProc
SetArcDirection
SetBitmapBits
SetBitmapDimensionEx
SetBkColor
SetBkMode
SetBoundsRect
SetBrushOrgEx
SetColorAdjustment
SetColorSpace
SetDIBColorTable
SetDIBits
SetDIBitsToDevice
SetDeviceGammaRamp
SetEnhMetaFileBits
SetFontEnumeration
SetGraphicsMode
SetICMMode
SetICMProfileA
SetICMProfileW
SetLayout
SetMagicColors
SetMapMode
SetMapperFlags
SetMetaFileBitsEx
SetMetaRgn
SetMiterLimit
SetObjectOwner
SetPaletteEntries
SetPixel
SetPixelFormat
SetPixelV
SetPolyFillMode
SetROP2
SetRectRgn
SetStretchBltMode
SetSystemPaletteUse
SetTextAlign
SetTextCharacterExtra
SetTextColor
SetTextJustification
SetViewportExtEx
SetViewportOrgEx
SetWinMetaFileBits
SetWindowExtEx
SetWindowOrgEx
SetWorldTransform
StartDocA
StartDocW
StartPage
StretchBlt
StretchDIBits
StrokeAndFillPath
StrokePath
SwapBuffers
TextOutA
TextOutW
TranslateCharsetInfo
UnrealizeObject
UpdateColors
UpdateICMRegKeyA
UpdateICMRegKeyW
WidenPath
gdiPlaySpoolStream
pfnRealizePalette
pfnSelectPalette
</pre></div>
</code></pre></div></td>
</tr>
</table>
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 true
        # even for recursive calls we need to check the lock levels (!):
        mergeLockLevels(tracked, n, a.sym.getLockLevel)
        if sfSideEffect in a.sym.flags: markSideEffect(tracked, a)
      else:
        mergeLockLevels(tracked, n, op.lockLevel)
      var effectList = op.n.sons[0]
      if a.kind == nkSym and a.sym.kind == skMethod:
        propagateEffects(tracked, n, a.sym)
      elif isNoEffectList(effectList):
        if isForwardedProc(a):
          propagateEffects(tracked, n, a.sym)
        elif isIndirectCall(a, tracked.owner):
          assumeTheWorst(tracked, n, op)
      else:
        mergeEffects(tracked, effectList.sons[exceptionEffects], n)
        mergeTags(tracked, effectList.sons[tagEffects], n)
        if notGcSafe(op) and not importedFromC(a):
          # and it's not a recursive call:
          if not (a.kind == nkSym and a.sym == tracked.owner):
            if warnGcUnsafe in tracked.config.notes: warnAboutGcUnsafe(n, tracked.config)
            markGcUnsafe(tracked, a)
        if tfNoSideEffect notin op.flags and not importedFromC(a):
          # and it's not a recursive call:
          if not (a.kind == nkSym and a.sym == tracked.owner):
            markSideEffect(tracked, a)
    if a.kind != nkSym or a.sym.magic != mNBindSym:
      for i in 1 ..< len(n): trackOperand(tracked, n.sons[i], paramType(op, i))
    if a.kind == nkSym and a.sym.magic in {mNew, mNewFinalize, mNewSeq}:
      # may not look like an assignment, but it is:
      let arg = n.sons[1]
      initVarViaNew(tracked, arg)
      if arg.typ.len != 0 and {tfNeedsInit} * arg.typ.lastSon.flags != {}:
        if a.sym.magic == mNewSeq and n[2].kind in {nkCharLit..nkUInt64Lit} and
            n[2].intVal == 0:
          # var s: seq[notnil];  newSeq(s, 0)  is a special case!
          discard
        else:
          message(tracked.config, arg.info, warnProveInit, $arg)
    for i in 0 ..< safeLen(n):
      track(tracked, n.sons[i])
  of nkDotExpr:
    guardDotAccess(tracked, n)
    for i in 0 ..< len(n): track(tracked, n.sons[i])
  of nkCheckedFieldExpr:
    track(tracked, n.sons[0])
    if warnProveField in tracked.config.notes:
      checkFieldAccess(tracked.guards, n, tracked.config)
  of nkTryStmt: trackTryStmt(tracked, n)
  of nkPragma: trackPragmaStmt(tracked, n)
  of nkAsgn, nkFastAsgn:
    track(tracked, n.sons[1])
    initVar(tracked, n.sons[0], volatileCheck=true)
    invalidateFacts(tracked.guards, n.sons[0])
    track(tracked, n.sons[0])
    addAsgnFact(tracked.guards, n.sons[0], n.sons[1])
    notNilCheck(tracked, n.sons[1], n.sons[0].typ)
    when false: cstringCheck(tracked, n)
  of nkVarSection, nkLetSection:
    for child in n:
      let last = lastSon(child)
      if last.kind != nkEmpty: track(tracked, last)
      if child.kind == nkIdentDefs and last.kind != nkEmpty:
        for i in 0 .. child.len-3:
          initVar(tracked, child.sons[i], volatileCheck=false)
          addAsgnFact(tracked.guards, child.sons[i], last)
          notNilCheck(tracked, last, child.sons[i].typ)
      elif child.kind == nkVarTuple and last.kind != nkEmpty:
        for i in 0 .. child.len-2:
          if child[i].kind == nkEmpty or
            child[i].kind == nkSym and child[i].sym.name.s == "_":
            continue
          initVar(tracked, child[i], volatileCheck=false)
          if last.kind in {nkPar, nkTupleConstr}:
            addAsgnFact(tracked.guards, child[i], last[i])
            notNilCheck(tracked, last[i], child[i].typ)
      # since 'var (a, b): T = ()' is not even allowed, there is always type
      # inference for (a, b) and thus no nil checking is necessary.
  of nkConstSection:
    for child in n:
      let last = lastSon(child)
      track(tracked, last)
  of nkCaseStmt: trackCase(tracked, n)
  of nkWhen, nkIfStmt, nkIfExpr: trackIf(tracked, n)
  of nkBlockStmt, nkBlockExpr: trackBlock(tracked, n.sons[1])
  of nkWhileStmt:
    track(tracked, n.sons[0])
    # 'while true' loop?
    if isTrue(n.sons[0]):
      trackBlock(tracked, n.sons[1])
    else:
      # loop may never execute:
      let oldState = tracked.init.len
      let oldFacts = tracked.guards.s.len
      addFact(tracked.guards, n.sons[0])
      track(tracked, n.sons[1])
      setLen(tracked.init, oldState)
      setLen(tracked.guards.s, oldFacts)
  of nkForStmt, nkParForStmt:
    # we are very conservative here and assume the loop is never executed:
    let oldState = tracked.init.len
    for i in 0 ..< len(n):
      track(tracked, n.sons[i])
    setLen(tracked.init, oldState)
  of nkObjConstr:
    when false: track(tracked, n.sons[0])
    let oldFacts = tracked.guards.s.len
    for i in 1 ..< len(n):
      let x = n.sons[i]
      track(tracked, x)
      if x.sons[0].kind == nkSym and sfDiscriminant in x.sons[0].sym.flags:
        addDiscriminantFact(tracked.guards, x)
    setLen(tracked.guards.s, oldFacts)
  of nkPragmaBlock:
    let pragmaList = n.sons[0]
    let oldLocked = tracked.locked.len
    let oldLockLevel = tracked.currLockLevel
    var enforcedGcSafety = false
    var enforceNoSideEffects = false
    for i in 0 ..< pragmaList.len:
      let pragma = whichPragma(pragmaList.sons[i])
      if pragma == wLocks:
        lockLocations(tracked, pragmaList.sons[i])
      elif pragma == wGcSafe:
        enforcedGcSafety = true
      elif pragma == wNosideeffect:
        enforceNoSideEffects = true
    if enforcedGcSafety: tracked.inEnforcedGcSafe = true
    if enforceNoSideEffects: tracked.inEnforcedNoSideEffects = true
    track(tracked, n.lastSon)
    if enforcedGcSafety: tracked.inEnforcedGcSafe = false
    if enforceNoSideEffects: tracked.inEnforcedNoSideEffects = false
    setLen(tracked.locked, oldLocked)
    tracked.currLockLevel = oldLockLevel
  of nkTypeSection, nkProcDef, nkConverterDef, nkMethodDef, nkIteratorDef,
      nkMacroDef, nkTemplateDef, nkLambda, nkDo, nkFuncDef:
    discard
  of nkCast, nkHiddenStdConv, nkHiddenSubConv, nkConv:
    if n.len == 2: track(tracked, n.sons[1])
  of nkObjUpConv, nkObjDownConv, nkChckRange, nkChckRangeF, nkChckRange64:
    if n.len == 1: track(tracked, n.sons[0])
  else:
    for i in 0 ..< safeLen(n): track(tracked, n.sons[i])

proc subtypeRelation(g: ModuleGraph; spec, real: PNode): bool =
  result = safeInheritanceDiff(g.excType(real), spec.typ) <= 0

proc checkRaisesSpec(g: ModuleGraph; spec, real: PNode, msg: string, hints: bool;
                     effectPredicate: proc (g: ModuleGraph; a, b: PNode): bool {.nimcall.}) =
  # check that any real exception is listed in 'spec'; mark those as used;
  # report any unused exception
  var used = initIntSet()
  for r in items(real):
    block search:
      for s in 0 ..< spec.len:
        if effectPredicate(g, spec[s], r):
          used.incl(s)
          break search
      # XXX call graph analysis would be nice here!
      pushInfoContext(g.config, spec.info)
      localError(g.config, r.info, errGenerated, msg & typeToString(r.typ))
      popInfoContext(g.config)
  # hint about unnecessarily listed exception types:
  if hints:
    for s in 0 ..< spec.len:
      if not used.contains(s):
        message(g.config, spec[s].info, hintXDeclaredButNotUsed, renderTree(spec[s]))

proc checkMethodEffects*(g: ModuleGraph; disp, branch: PSym) =
  ## checks for consistent effects for multi methods.
  let actual = branch.typ.n.sons[0]
  if actual.len != effectListLen: return

  let p = disp.ast.sons[pragmasPos]
  let raisesSpec = effectSpec(p, wRaises)
  if not isNil(raisesSpec):
    checkRaisesSpec(g, raisesSpec, actual.sons[exceptionEffects],
      "can raise an unlisted exception: ", hints=off, subtypeRelation)
  let tagsSpec = effectSpec(p, wTags)
  if not isNil(tagsSpec):
    checkRaisesSpec(g, tagsSpec, actual.sons[tagEffects],
      "can have an unlisted effect: ", hints=off, subtypeRelation)
  if sfThread in disp.flags and notGcSafe(branch.typ):
    localError(g.config, branch.info, "base method is GC-safe, but '$1' is not" %
                                branch.name.s)
  if branch.typ.lockLevel > disp.typ.lockLevel:
    when true:
      message(g.config, branch.info, warnLockLevel,
        "base method has lock level $1, but dispatcher has $2" %
          [$branch.typ.lockLevel, $disp.typ.lockLevel])
    else:
      # XXX make this an error after bigbreak has been released:
      localError(g.config, branch.info,
        "base method has lock level $1, but dispatcher has $2" %
          [$branch.typ.lockLevel, $disp.typ.lockLevel])

proc setEffectsForProcType*(g: ModuleGraph; t: PType, n: PNode) =
  var effects = t.n[0]
  if t.kind != tyProc or effects.kind != nkEffectList: return
  if n.kind != nkEmpty:
    internalAssert g.config, effects.len == 0
    newSeq(effects.sons, effectListLen)
    let raisesSpec = effectSpec(n, wRaises)
    if not isNil(raisesSpec):
      effects[exceptionEffects] = raisesSpec
    let tagsSpec = effectSpec(n, wTags)
    if not isNil(tagsSpec):
      effects[tagEffects] = tagsSpec
    effects[pragmasEffects] = n

proc initEffects(g: ModuleGraph; effects: PNode; s: PSym; t: var TEffects) =
  newSeq(effects.sons, effectListLen)
  effects.sons[exceptionEffects] = newNodeI(nkArgList, s.info)
  effects.sons[tagEffects] = newNodeI(nkArgList, s.info)
  effects.sons[usesEffects] = g.emptyNode
  effects.sons[writeEffects] = g.emptyNode
  effects.sons[pragmasEffects] = g.emptyNode

  t.exc = effects.sons[exceptionEffects]
  t.tags = effects.sons[tagEffects]
  t.owner = s
  t.owner_module = s.getModule
  t.init = @[]
  t.guards.s = @[]
  t.guards.o = initOperators(g)
  t.locked = @[]
  t.graph = g
  t.config = g.config

proc trackProc*(g: ModuleGraph; s: PSym, body: PNode) =
  var effects = s.typ.n.sons[0]
  if effects.kind != nkEffectList: return
  # effects already computed?
  if sfForward in s.flags: return
  if effects.len == effectListLen: return

  var t: TEffects
  initEffects(g, effects, s, t)
  track(t, body)
  if not isEmptyType(s.typ.sons[0]) and
      {tfNeedsInit, tfNotNil} * s.typ.sons[0].flags != {} and
      s.kind in {skProc, skFunc, skConverter, skMethod}:
    var res = s.ast.sons[resultPos].sym # get result symbol
    if res.id notin t.init:
      message(g.config, body.info, warnProveInit, "result")
  let p = s.ast.sons[pragmasPos]
  let raisesSpec = effectSpec(p, wRaises)
  if not isNil(raisesSpec):
    checkRaisesSpec(g, raisesSpec, t.exc, "can raise an unlisted exception: ",
                    hints=on, subtypeRelation)
    # after the check, use the formal spec:
    effects.sons[exceptionEffects] = raisesSpec

  let tagsSpec = effectSpec(p, wTags)
  if not isNil(tagsSpec):
    checkRaisesSpec(g, tagsSpec, t.tags, "can have an unlisted effect: ",
                    hints=off, subtypeRelation)
    # after the check, use the formal spec:
    effects.sons[tagEffects] = tagsSpec

  if sfThread in s.flags and t.gcUnsafe:
    if optThreads in g.config.globalOptions and optThreadAnalysis in g.config.globalOptions:
      #localError(s.info, "'$1' is not GC-safe" % s.name.s)
      listGcUnsafety(s, onlyWarning=false, g.config)
    else:
      listGcUnsafety(s, onlyWarning=true, g.config)
      #localError(s.info, warnGcUnsafe2, s.name.s)
  if sfNoSideEffect in s.flags and t.hasSideEffect:
    when false:
      listGcUnsafety(s, onlyWarning=false, g.config)
    else:
      localError(g.config, s.info, "'$1' can have side effects" % s.name.s)
  if not t.gcUnsafe:
    s.typ.flags.incl tfGcSafe
  if not t.hasSideEffect and sfSideEffect notin s.flags:
    s.typ.flags.incl tfNoSideEffect
  if s.typ.lockLevel == UnspecifiedLockLevel:
    s.typ.lockLevel = t.maxLockLevel
  elif t.maxLockLevel > s.typ.lockLevel:
    #localError(s.info,
    message(g.config, s.info, warnLockLevel,
      "declared lock level is $1, but real lock level is $2" %
        [$s.typ.lockLevel, $t.maxLockLevel])
  when defined(useDfa):
    if s.kind == skFunc:
      dataflowAnalysis(s, body)
      when false: trackWrites(s, body)

proc trackTopLevelStmt*(g: ModuleGraph; module: PSym; n: PNode) =
  if n.kind in {nkPragma, nkMacroDef, nkTemplateDef, nkProcDef, nkFuncDef,
                nkTypeSection, nkConverterDef, nkMethodDef, nkIteratorDef}:
    return
  var effects = newNode(nkEffectList, n.info)
  var t: TEffects
  initEffects(g, effects, module, t)
  t.isToplevel = true
  track(t, n)