Nim/compiler/pragmas.nim

#
#
#           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 semantic checking for pragmas

import
  condsyms, ast, astalgo, idents, semdata, msgs, renderer,
  wordrecg, ropes, options, extccomp, magicsys, trees,
  types, lookups, lineinfos, pathutils, linter, modulepaths

import std/[os, math, strutils]

when defined(nimPreviewSlimSystem):
  import std/assertions

from ic / ic import addCompilerProc

const
  FirstCallConv* = wNimcall
  LastCallConv* = wNoconv

const
  declPragmas = {wImportc, wImportObjC, wImportCpp, wImportJs, wExportc, wExportCpp,
    wExportNims, wExtern, wDeprecated, wNodecl, wError, wUsed}
    ## common pragmas for declarations, to a good approximation
  procPragmas* = declPragmas + {FirstCallConv..LastCallConv,
    wMagic, wNoSideEffect, wSideEffect, wNoreturn, wNosinks, wDynlib, wHeader,
    wCompilerProc, wNonReloadable, wCore, wProcVar, wVarargs, wCompileTime,
    wBorrow, wImportCompilerProc, wThread,
    wAsmNoStackFrame, wDiscardable, wNoInit, wCodegenDecl,
    wGensym, wInject, wRaises, wEffectsOf, wTags, wForbids, wLocks, wDelegator, wGcSafe,
    wConstructor, wLiftLocals, wStackTrace, wLineTrace, wNoDestroy,
    wRequires, wEnsures, wEnforceNoRaises, wSystemRaisesDefect, wVirtual, wQuirky, wMember}
  converterPragmas* = procPragmas
  methodPragmas* = procPragmas+{wBase}-{wImportCpp}
  templatePragmas* = {wDeprecated, wError, wGensym, wInject, wDirty,
    wDelegator, wExportNims, wUsed, wPragma, wRedefine, wCallsite}
  macroPragmas* = declPragmas + {FirstCallConv..LastCallConv,
    wMagic, wNoSideEffect, wCompilerProc, wNonReloadable, wCore,
    wDiscardable, wGensym, wInject, wDelegator}
  iteratorPragmas* = declPragmas + {FirstCallConv..LastCallConv, wNoSideEffect, wSideEffect,
    wMagic, wBorrow,
    wDiscardable, wGensym, wInject, wRaises, wEffectsOf,
    wTags, wForbids, wLocks, wGcSafe, wRequires, wEnsures}
  exprPragmas* = {wLine, wLocks, wNoRewrite, wGcSafe, wNoSideEffect}
  stmtPragmas* = {
    wHint, wWarning, wError,
    wFatal, wDefine, wUndef, wCompile, wLink, wLinksys, wPure, wPush, wPop,
    wPassl, wPassc, wLocalPassc,
    wDeadCodeElimUnused,  # deprecated, always on
    wDeprecated,
    wPragma, wEmit, wUnroll,
    wLinearScanEnd, wPatterns, wTrMacros, wEffects, wNoForward, wReorder, wComputedGoto,
    wExperimental, wDoctype, wThis, wUsed, wInvariant, wAssume, wAssert}
  stmtPragmasTopLevel* = {wChecks, wObjChecks, wFieldChecks, wRangeChecks,
    wBoundChecks, wOverflowChecks, wNilChecks, wStaticBoundchecks,
    wStyleChecks, wAssertions,
    wWarnings, wHints,
    wLineDir, wStackTrace, wLineTrace, wOptimization,
    wFloatChecks, wInfChecks, wNanChecks}
  lambdaPragmas* = {FirstCallConv..LastCallConv,
    wNoSideEffect, wSideEffect, wNoreturn, wNosinks, wDynlib, wHeader,
    wThread, wAsmNoStackFrame,
    wRaises, wLocks, wTags, wForbids, wRequires, wEnsures, wEffectsOf,
    wGcSafe, wCodegenDecl, wNoInit, wCompileTime}
  typePragmas* = declPragmas + {wMagic, wAcyclic,
    wPure, wHeader, wCompilerProc, wCore, wFinal, wSize, wShallow,
    wIncompleteStruct, wCompleteStruct, wByCopy, wByRef,
    wInheritable, wGensym, wInject, wRequiresInit, wUnchecked, wUnion, wPacked,
    wCppNonPod, wBorrow, wGcSafe, wPartial, wExplain, wPackage, wCodegenDecl,
    wSendable, wNoInit}
  fieldPragmas* = declPragmas + {wGuard, wBitsize, wCursor,
    wRequiresInit, wNoalias, wAlign, wNoInit} - {wExportNims, wNodecl} # why exclude these?
  varPragmas* = declPragmas + {wVolatile, wRegister, wThreadVar,
    wMagic, wHeader, wCompilerProc, wCore, wDynlib,
    wNoInit, wCompileTime, wGlobal,
    wGensym, wInject, wCodegenDecl,
    wGuard, wGoto, wCursor, wNoalias, wAlign}
  constPragmas* = declPragmas + {wHeader, wMagic,
    wGensym, wInject,
    wIntDefine, wStrDefine, wBoolDefine, wDefine,
    wCompilerProc, wCore}
  paramPragmas* = {wNoalias, wInject, wGensym, wByRef, wByCopy, wCodegenDecl}
  letPragmas* = varPragmas
  procTypePragmas* = {FirstCallConv..LastCallConv, wVarargs, wNoSideEffect,
                      wThread, wRaises, wEffectsOf, wLocks, wTags, wForbids, wGcSafe,
                      wRequires, wEnsures}
  forVarPragmas* = {wInject, wGensym}
  allRoutinePragmas* = methodPragmas + iteratorPragmas + lambdaPragmas
  enumFieldPragmas* = {wDeprecated}

proc getPragmaVal*(procAst: PNode; name: TSpecialWord): PNode =
  result = nil
  let p = procAst[pragmasPos]
  if p.kind == nkEmpty: return nil
  for it in p:
    if it.kind in nkPragmaCallKinds and it.len == 2 and it[0].kind == nkIdent and
        it[0].ident.id == ord(name):
      return it[1]

proc pragma*(c: PContext, sym: PSym, n: PNode, validPragmas: TSpecialWords;
            isStatement: bool = false)

proc recordPragma(c: PContext; n: PNode; args: varargs[string]) =
  var recorded = newNodeI(nkReplayAction, n.info)
  for i in 0..args.high:
    recorded.add newStrNode(args[i], n.info)
  addPragmaComputation(c, recorded)

const
  errStringLiteralExpected = "string literal expected"
  errIntLiteralExpected = "integer literal expected"

proc invalidPragma*(c: PContext; n: PNode) =
  localError(c.config, n.info, "invalid pragma: " & renderTree(n, {renderNoComments}))
proc illegalCustomPragma*(c: PContext, n: PNode, s: PSym) =
  var msg = "cannot attach a custom pragma to '" & s.name.s & "'"
  if s != nil:
    msg.add("; custom pragmas are not supported for ")
    case s.kind
    of skForVar: msg.add("`for` loop variables")
    of skEnumField: msg.add("enum fields")
    of skModule: msg.add("modules")
    else: msg.add("symbol kind " & $s.kind)
  localError(c.config, n.info, msg)

proc pragmaProposition(c: PContext, n: PNode) =
  if n.kind notin nkPragmaCallKinds or n.len != 2:
    localError(c.config, n.info, "proposition expected")
  else:
    n[1] = c.semExpr(c, n[1])

proc pragmaEnsures(c: PContext, n: PNode) =
  if n.kind notin nkPragmaCallKinds or n.len != 2:
    localError(c.config, n.info, "proposition expected")
  else:
    openScope(c)
    let o = getCurrOwner(c)
    if o.kind in routineKinds and o.typ != nil and o.typ[0] != nil:
      var s = newSym(skResult, getIdent(c.cache, "result"), c.idgen, o, n.info)
      s.typ = o.typ[0]
      incl(s.flags, sfUsed)
      addDecl(c, s)
    n[1] = c.semExpr(c, n[1])
    closeScope(c)

proc pragmaAsm*(c: PContext, n: PNode): char =
  result = '\0'
  if n != nil:
    for i in 0..<n.len:
      let it = n[i]
      if it.kind in nkPragmaCallKinds and it.len == 2 and it[0].kind == nkIdent:
        case whichKeyword(it[0].ident)
        of wSubsChar:
          if it[1].kind == nkCharLit: result = chr(int(it[1].intVal))
          else: invalidPragma(c, it)
        else: invalidPragma(c, it)
      else:
        invalidPragma(c, it)

proc setExternName(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  # special cases to improve performance:
  if extname == "$1":
    s.loc.r = rope(s.name.s)
  elif '$' notin extname:
    s.loc.r = rope(extname)
  else:
    try:
      s.loc.r = rope(extname % s.name.s)
    except ValueError:
      localError(c.config, info, "invalid extern name: '" & extname & "'. (Forgot to escape '$'?)")
  when hasFFI:
    s.cname = $s.loc.r


proc makeExternImport(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  setExternName(c, s, extname, info)
  incl(s.flags, sfImportc)
  excl(s.flags, sfForward)

proc makeExternExport(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  setExternName(c, s, extname, info)
  incl(s.flags, sfExportc)

proc processImportCompilerProc(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  setExternName(c, s, extname, info)
  incl(s.flags, sfImportc)
  excl(s.flags, sfForward)
  incl(s.loc.flags, lfImportCompilerProc)

proc processImportCpp(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  setExternName(c, s, extname, info)
  incl(s.flags, sfImportc)
  incl(s.flags, sfInfixCall)
  excl(s.flags, sfForward)
  if c.config.backend == backendC:
    let m = s.getModule()
    incl(m.flags, sfCompileToCpp)
  incl c.config.globalOptions, optMixedMode

proc processImportObjC(c: PContext; s: PSym, extname: string, info: TLineInfo) =
  setExternName(c, s, extname, info)
  incl(s.flags, sfImportc)
  incl(s.flags, sfNamedParamCall)
  excl(s.flags, sfForward)
  let m = s.getModule()
  incl(m.flags, sfCompileToObjc)

proc newEmptyStrNode(c: PContext; n: PNode, strVal: string = ""): PNode {.noinline.} =
  result = newNodeIT(nkStrLit, n.info, getSysType(c.graph, n.info, tyString))
  result.strVal = strVal

proc getStrLitNode(c: PContext, n: PNode): PNode =
  if n.kind notin nkPragmaCallKinds or n.len != 2:
    localError(c.config, n.info, errStringLiteralExpected)
    # error correction:
    result = newEmptyStrNode(c, n)
  else:
    n[1] = c.semConstExpr(c, n[1])
    case n[1].kind
    of nkStrLit, nkRStrLit, nkTripleStrLit: result = n[1]
    else:
      localError(c.config, n.info, errStringLiteralExpected)
      # error correction:
      result = newEmptyStrNode(c, n)

proc expectStrLit(c: PContext, n: PNode): string =
  result = getStrLitNode(c, n).strVal

proc expectIntLit(c: PContext, n: PNode): int =
  result = 0
  if n.kind notin nkPragmaCallKinds or n.len != 2:
    localError(c.config, n.info, errIntLiteralExpected)
  else:
    n[1] = c.semConstExpr(c, n[1])
    case n[1].kind
    of nkIntLit..nkInt64Lit: result = int(n[1].intVal)
    else: localError(c.config, n.info, errIntLiteralExpected)

proc getOptionalStr(c: PContext, n: PNode, defaultStr: string): string =
  if n.kind in nkPragmaCallKinds: result = expectStrLit(c, n)
  else: result = defaultStr

proc processVirtual(c: PContext, n: PNode, s: PSym, flag: TSymFlag) =
  s.constraint = newEmptyStrNode(c, n, getOptionalStr(c, n, "$1"))
  s.constraint.strVal = s.constraint.strVal % s.name.s
  s.flags.incl {flag, sfInfixCall, sfExportc, sfMangleCpp}

  s.typ.callConv = ccNoConvention
  incl c.config.globalOptions, optMixedMode

proc processCodegenDecl(c: PContext, n: PNode, sym: PSym) =
  sym.constraint = getStrLitNode(c, n)
  sym.flags.incl sfCodegenDecl

proc processMagic(c: PContext, n: PNode, s: PSym) =
  #if sfSystemModule notin c.module.flags:
  #  liMessage(n.info, errMagicOnlyInSystem)
  if n.kind notin nkPragmaCallKinds or n.len != 2:
    localError(c.config, n.info, errStringLiteralExpected)
    return
  var v: string
  if n[1].kind == nkIdent: v = n[1].ident.s
  else: v = expectStrLit(c, n)
  for m in TMagic:
    if substr($m, 1) == v:
      s.magic = m
      break
  if s.magic == mNone: message(c.config, n.info, warnUnknownMagic, v)

proc wordToCallConv(sw: TSpecialWord): TCallingConvention =
  # this assumes that the order of special words and calling conventions is
  # the same
  TCallingConvention(ord(ccNimCall) + ord(sw) - ord(wNimcall))

proc isTurnedOn(c: PContext, n: PNode): bool =
  result = false
  if n.kind in nkPragmaCallKinds and n.len == 2:
    let x = c.semConstBoolExpr(c, n[1])
    n[1] = x
    if x.kind == nkIntLit: return x.intVal != 0
  localError(c.config, n.info, "'on' or 'off' expected")

proc onOff(c: PContext, n: PNode, op: TOptions, resOptions: var TOptions) =
  if isTurnedOn(c, n): resOptions.incl op
  else: resOptions.excl op

proc pragmaNoForward*(c: PContext, n: PNode; flag=sfNoForward) =
  if isTurnedOn(c, n):
    incl(c.module.flags, flag)
    c.features.incl codeReordering
  else:
    excl(c.module.flags, flag)
    # c.features.excl codeReordering

  # deprecated as of 0.18.1
  message(c.config, n.info, warnDeprecated,
          "use {.experimental: \"codeReordering\".} instead; " &
          (if flag == sfNoForward: "{.noForward.}" else: "{.reorder.}") & " is deprecated")

proc processCallConv(c: PContext, n: PNode) =
  if n.kind in nkPragmaCallKinds and n.len == 2 and n[1].kind == nkIdent:
    let sw = whichKeyword(n[1].ident)
    case sw
    of FirstCallConv..LastCallConv:
      c.optionStack[^1].defaultCC = wordToCallConv(sw)
    else: localError(c.config, n.info, "calling convention expected")
  else:
    localError(c.config, n.info, "calling convention expected")

proc getLib(c: PContext, kind: TLibKind, path: PNode): PLib =
  for it in c.libs:
    if it.kind == kind and trees.exprStructuralEquivalent(it.path, path):
      return it

  result = newLib(kind)
  result.path = path
  c.libs.add result
  if path.kind in {nkStrLit..nkTripleStrLit}:
    result.isOverridden = options.isDynlibOverride(c.config, path.strVal)

proc expectDynlibNode(c: PContext, n: PNode): PNode =
  if n.kind notin nkPragmaCallKinds or n.len != 2:
    localError(c.config, n.info, errStringLiteralExpected)
    # error correction:
    result = newEmptyStrNode(c, n)
  else:
    # For the OpenGL wrapper we support:
    # {.dynlib: myGetProcAddr(...).}
    result = c.semExpr(c, n[1])
    if result.kind == nkSym and result.sym.kind == skConst:
      result = c.semConstExpr(c, result) # fold const
    if result.typ == nil or result.typ.kind notin {tyPointer, tyString, tyProc}:
      localError(c.config, n.info, errStringLiteralExpected)
      result = newEmptyStrNode(c, n)

proc processDynLib(c: PContext, n: PNode, sym: PSym) =
  if (sym == nil) or (sym.kind == skModule):
    let lib = getLib(c, libDynamic, expectDynlibNode(c, n))
    if not lib.isOverridden:
      c.optionStack[^1].dynlib = lib
  else:
    if n.kind in nkPragmaCallKinds:
      var lib = getLib(c, libDynamic, expectDynlibNode(c, n))
      if not lib.isOverridden:
        addToLib(lib, sym)
        incl(sym.loc.flags, lfDynamicLib)
    else:
      incl(sym.loc.flags, lfExportLib)
    # since we'll be loading the dynlib symbols dynamically, we must use
    # a calling convention that doesn't introduce custom name mangling
    # cdecl is the default - the user can override this explicitly
    if sym.kind in routineKinds and sym.typ != nil and
       tfExplicitCallConv notin sym.typ.flags:
      sym.typ.callConv = ccCDecl

proc processNote(c: PContext, n: PNode) =
  template handleNote(enumVals, notes) =
    let x = findStr(enumVals.a, enumVals.b, n[0][1].ident.s, errUnknown)
    if x !=  errUnknown:
      nk = TNoteKind(x)
      let x = c.semConstBoolExpr(c, n[1])
      n[1] = x
      if x.kind == nkIntLit and x.intVal != 0: incl(notes, nk)
      else: excl(notes, nk)
    else:
      invalidPragma(c, n)

  if n.kind in nkPragmaCallKinds and n.len == 2 and
      n[0].kind == nkBracketExpr and
      n[0].len == 2 and
      n[0][1].kind == nkIdent and n[0][0].kind == nkIdent:
    var nk: TNoteKind
    case whichKeyword(n[0][0].ident)
    of wHint: handleNote(hintMin .. hintMax, c.config.notes)
    of wWarning: handleNote(warnMin .. warnMax, c.config.notes)
    of wWarningAsError: handleNote(warnMin .. warnMax, c.config.warningAsErrors)
    of wHintAsError: handleNote(hintMin .. hintMax, c.config.warningAsErrors)
    else: invalidPragma(c, n)
  else: invalidPragma(c, n)

proc pragmaToOptions*(w: TSpecialWord): TOptions {.inline.} =
  case w
  of wChecks: ChecksOptions
  of wObjChecks: {optObjCheck}
  of wFieldChecks: {optFieldCheck}
  of wRangeChecks: {optRangeCheck}
  of wBoundChecks: {optBoundsCheck}
  of wOverflowChecks: {optOverflowCheck}
  of wFloatChecks: {optNaNCheck, optInfCheck}
  of wNanChecks: {optNaNCheck}
  of wInfChecks: {optInfCheck}
  of wStaticBoundchecks: {optStaticBoundsCheck}
  of wStyleChecks: {optStyleCheck}
  of wAssertions: {optAssert}
  of wWarnings: {optWarns}
  of wHints: {optHints}
  of wLineDir: {optLineDir}
  of wStackTrace: {optStackTrace}
  of wLineTrace: {optLineTrace}
  of wDebugger: {optNone}
  of wProfiler: {optProfiler, optMemTracker}
  of wMemTracker: {optMemTracker}
  of wByRef: {optByRef}
  of wImplicitStatic: {optImplicitStatic}
  of wPatterns, wTrMacros: {optTrMacros}
  of wSinkInference: {optSinkInference}
  of wQuirky: {optQuirky}
  else: {}

proc processExperimental(c: PContext; n: PNode) =
  if n.kind notin nkPragmaCallKinds or n.len != 2:
    c.features.incl oldExperimentalFeatures
  else:
    n[1] = c.semConstExpr(c, n[1])
    case n[1].kind
    of nkStrLit, nkRStrLit, nkTripleStrLit:
      try:
        let feature = parseEnum[Feature](n[1].strVal)
        c.features.incl feature
        if feature == codeReordering:
          if not isTopLevel(c):
              localError(c.config, n.info,
                         "Code reordering experimental pragma only valid at toplevel")
          c.module.flags.incl sfReorder
      except ValueError:
        localError(c.config, n[1].info, "unknown experimental feature")
    else:
      localError(c.config, n.info, errStringLiteralExpected)

proc tryProcessOption(c: PContext, n: PNode, resOptions: var TOptions): bool =
  result = true
  if n.kind notin nkPragmaCallKinds or n.len != 2: result = false
  elif n[0].kind == nkBracketExpr: processNote(c, n)
  elif n[0].kind != nkIdent: result = false
  else:
    let sw = whichKeyword(n[0].ident)
    if sw == wExperimental:
      processExperimental(c, n)
      return true
    let opts = pragmaToOptions(sw)
    if opts != {}:
      onOff(c, n, opts, resOptions)
    else:
      case sw
      of wCallconv: processCallConv(c, n)
      of wDynlib: processDynLib(c, n, nil)
      of wOptimization:
        if n[1].kind != nkIdent:
          invalidPragma(c, n)
        else:
          case n[1].ident.s.normalize
          of "speed":
            incl(resOptions, optOptimizeSpeed)
            excl(resOptions, optOptimizeSize)
          of "size":
            excl(resOptions, optOptimizeSpeed)
            incl(resOptions, optOptimizeSize)
          of "none":
            excl(resOptions, optOptimizeSpeed)
            excl(resOptions, optOptimizeSize)
          else: localError(c.config, n.info, "'none', 'speed' or 'size' expected")
      else: result = false

proc processOption(c: PContext, n: PNode, resOptions: var TOptions) =
  if not tryProcessOption(c, n, resOptions):
    # calling conventions (boring...):
    localError(c.config, n.info, "option expected")

proc processPush(c: PContext, n: PNode, start: int) =
  if n[start-1].kind in nkPragmaCallKinds:
    localError(c.config, n.info, "'push' cannot have arguments")
  var x = pushOptionEntry(c)
  for i in start..<n.len:
    if not tryProcessOption(c, n[i], c.config.options):
      # simply store it somewhere:
      if x.otherPragmas.isNil:
        x.otherPragmas = newNodeI(nkPragma, n.info)
      x.otherPragmas.add n[i]
    #localError(c.config, n.info, errOptionExpected)

  # If stacktrace is disabled globally we should not enable it
  if optStackTrace notin c.optionStack[0].options:
    c.config.options.excl(optStackTrace)
  when defined(debugOptions):
    echo c.config $ n.info, " PUSH config is now ", c.config.options

proc processPop(c: PContext, n: PNode) =
  if c.optionStack.len <= 1:
    localError(c.config, n.info, "{.pop.} without a corresponding {.push.}")
  else:
    popOptionEntry(c)
  when defined(debugOptions):
    echo c.config $ n.info, " POP config is now ", c.config.options

proc processDefineConst(c: PContext, n: PNode, sym: PSym, kind: TMagic) =
  sym.magic = kind
  if n.kind in nkPragmaCallKinds and n.len == 2:
    # could also use TLib
    n[1] = getStrLitNode(c, n)

proc processDefine(c: PContext, n: PNode, sym: PSym) =
  if sym != nil and sym.kind == skConst:
    processDefineConst(c, n, sym, mGenericDefine)
  elif (n.kind in nkPragmaCallKinds and n.len == 2) and (n[1].kind == nkIdent):
    defineSymbol(c.config.symbols, n[1].ident.s)
  else:
    invalidPragma(c, n)

proc processUndef(c: PContext, n: PNode) =
  if (n.kind in nkPragmaCallKinds and n.len == 2) and (n[1].kind == nkIdent):
    undefSymbol(c.config.symbols, n[1].ident.s)
  else:
    invalidPragma(c, n)

proc relativeFile(c: PContext; n: PNode; ext=""): AbsoluteFile =
  var s = expectStrLit(c, n)
  if ext.len > 0 and splitFile(s).ext == "":
    s = addFileExt(s, ext)
  result = AbsoluteFile parentDir(toFullPath(c.config, n.info)) / s
  if not fileExists(result):
    if isAbsolute(s): result = AbsoluteFile s
    else:
      result = findFile(c.config, s)
      if result.isEmpty: result = AbsoluteFile s

proc processCompile(c: PContext, n: PNode) =
  ## This pragma can take two forms. The first is a simple file input:
  ##     {.compile: "file.c".}
  ## The second is a tuple where the second arg is the output name strutils formatter:
  ##     {.compile: ("file.c", "$1.o").}
  proc docompile(c: PContext; it: PNode; src, dest: AbsoluteFile; customArgs: string) =
    var cf = Cfile(nimname: splitFile(src).name,
                   cname: src, obj: dest, flags: {CfileFlag.External},
                   customArgs: customArgs)
    if not fileExists(src):
      localError(c.config, n.info, "cannot find: " & src.string)
    else:
      extccomp.addExternalFileToCompile(c.config, cf)
      recordPragma(c, it, "compile", src.string, dest.string, customArgs)

  proc getStrLit(c: PContext, n: PNode; i: int): string =
    n[i] = c.semConstExpr(c, n[i])
    case n[i].kind
    of nkStrLit, nkRStrLit, nkTripleStrLit:
      when defined(gcArc) or defined(gcOrc) or defined(gcAtomicArc):
        result = n[i].strVal
      else:
        shallowCopy(result, n[i].strVal)
    else:
      localError(c.config, n.info, errStringLiteralExpected)
      result = ""

  let it = if n.kind in nkPragmaCallKinds and n.len == 2: n[1] else: n
  if it.kind in {nkPar, nkTupleConstr} and it.len == 2:
    let s = getStrLit(c, it, 0)
    let dest = getStrLit(c, it, 1)
    var found = parentDir(toFullPath(c.config, n.info)) / s
    for f in os.walkFiles(found):
      let obj = completeCfilePath(c.config, AbsoluteFile(dest % extractFilename(f)))
      docompile(c, it, AbsoluteFile f, obj, "")
  else:
    var s = ""
    var customArgs = ""
    if n.kind in nkCallKinds:
      s = getStrLit(c, n, 1)
      if n.len <= 3:
        customArgs = getStrLit(c, n, 2)
      else:
        localError(c.config, n.info, "'.compile' pragma takes up 2 arguments")
    else:
      s = expectStrLit(c, n)

    var found = AbsoluteFile(parentDir(toFullPath(c.config, n.info)) / s)
    if not fileExists(found):
      if isAbsolute(s): found = AbsoluteFile s
      else:
        found = findFile(c.config, s)
        if found.isEmpty: found = AbsoluteFile s
    let mangled = completeCfilePath(c.config, mangleModuleName(c.config, found).AbsoluteFile)
    let obj = toObjFile(c.config, mangled)
    docompile(c, it, found, obj, customArgs)

proc processLink(c: PContext, n: PNode) =
  let found = relativeFile(c, n, CC[c.config.cCompiler].objExt)
  extccomp.addExternalFileToLink(c.config, found)
  recordPragma(c, n, "link", found.string)

proc semAsmOrEmit*(con: PContext, n: PNode, marker: char): PNode =
  case n[1].kind
  of nkStrLit, nkRStrLit, nkTripleStrLit:
    result = newNodeI(if n.kind == nkAsmStmt: nkAsmStmt else: nkArgList, n.info)
    var str = n[1].strVal
    if str == "":
      localError(con.config, n.info, "empty 'asm' statement")
      return
    # now parse the string literal and substitute symbols:
    var a = 0
    while true:
      var b = strutils.find(str, marker, a)
      var sub = if b < 0: substr(str, a) else: substr(str, a, b - 1)
      if sub != "": result.add newStrNode(nkStrLit, sub)
      if b < 0: break
      var c = strutils.find(str, marker, b + 1)
      if c < 0: sub = substr(str, b + 1)
      else: sub = substr(str, b + 1, c - 1)
      if sub != "":
        var amb = false
        var e = searchInScopes(con, getIdent(con.cache, sub), amb)
        # XXX what to do here if 'amb' is true?
        if e != nil:
          incl(e.flags, sfUsed)
          result.add newSymNode(e)
        else:
          result.add newStrNode(nkStrLit, sub)
      else:
        # an empty '``' produces a single '`'
        result.add newStrNode(nkStrLit, $marker)
      if c < 0: break
      a = c + 1
  else:
    illFormedAstLocal(n, con.config)
    result = newNodeI(nkAsmStmt, n.info)

proc pragmaEmit(c: PContext, n: PNode) =
  if n.kind notin nkPragmaCallKinds or n.len != 2:
    localError(c.config, n.info, errStringLiteralExpected)
  else:
    let n1 = n[1]
    if n1.kind == nkBracket:
      var b = newNodeI(nkBracket, n1.info, n1.len)
      for i in 0..<n1.len:
        b[i] = c.semExprWithType(c, n1[i], {efTypeAllowed})
      n[1] = b
    else:
      n[1] = c.semConstExpr(c, n1)
      case n[1].kind
      of nkStrLit, nkRStrLit, nkTripleStrLit:
        n[1] = semAsmOrEmit(c, n, '`')
      else:
        localError(c.config, n.info, errStringLiteralExpected)

proc noVal(c: PContext; n: PNode) =
  if n.kind in nkPragmaCallKinds and n.len > 1: invalidPragma(c, n)

proc pragmaUnroll(c: PContext, n: PNode) =
  if c.p.nestedLoopCounter <= 0:
    invalidPragma(c, n)
  elif n.kind in nkPragmaCallKinds and n.len == 2:
    var unrollFactor = expectIntLit(c, n)
    if unrollFactor <% 32:
      n[1] = newIntNode(nkIntLit, unrollFactor)
    else:
      invalidPragma(c, n)

proc pragmaLine(c: PContext, n: PNode) =
  if n.kind in nkPragmaCallKinds and n.len == 2:
    n[1] = c.semConstExpr(c, n[1])
    let a = n[1]
    if a.kind in {nkPar, nkTupleConstr}:
      # unpack the tuple
      var x = a[0]
      var y = a[1]
      if x.kind == nkExprColonExpr: x = x[1]
      if y.kind == nkExprColonExpr: y = y[1]
      if x.kind != nkStrLit:
        localError(c.config, n.info, errStringLiteralExpected)
      elif y.kind != nkIntLit:
        localError(c.config, n.info, errIntLiteralExpected)
      else:
        n.info.fileIndex = fileInfoIdx(c.config, AbsoluteFile(x.strVal))
        n.info.line = uint16(y.intVal)
    else:
      localError(c.config, n.info, "tuple expected")
  else:
    # sensible default:
    n.info = getInfoContext(c.config, -1)

proc processPragma(c: PContext, n: PNode, i: int) =
  ## Create and add a new custom pragma `{.pragma: name.}` node to the module's context.
  let it = n[i]
  if it.kind notin nkPragmaCallKinds and it.safeLen == 2: invalidPragma(c, n)
  elif it.safeLen != 2 or it[0].kind != nkIdent or it[1].kind != nkIdent:
    invalidPragma(c, n)

  var userPragma = newSym(skTemplate, it[1].ident, c.idgen, c.module, it.info, c.config.options)
  styleCheckDef(c, userPragma)
  userPragma.ast = newTreeI(nkPragma, n.info, n.sons[i+1..^1])
  strTableAdd(c.userPragmas, userPragma)

proc pragmaRaisesOrTags(c: PContext, n: PNode) =
  proc processExc(c: PContext, x: PNode) =
    if c.hasUnresolvedArgs(c, x):
      x.typ = makeTypeFromExpr(c, x)
    else:
      var t = skipTypes(c.semTypeNode(c, x, nil), skipPtrs)
      if t.kind notin {tyObject, tyOr}:
        localError(c.config, x.info, errGenerated, "invalid type for raises/tags list")
      x.typ = t

  if n.kind in nkPragmaCallKinds and n.len == 2:
    let it = n[1]
    if it.kind notin {nkCurly, nkBracket}:
      processExc(c, it)
    else:
      for e in items(it): processExc(c, e)
  else:
    invalidPragma(c, n)

proc pragmaLockStmt(c: PContext; it: PNode) =
  if it.kind notin nkPragmaCallKinds or it.len != 2:
    invalidPragma(c, it)
  else:
    let n = it[1]
    if n.kind != nkBracket:
      localError(c.config, n.info, errGenerated, "locks pragma takes a list of expressions")
    else:
      for i in 0..<n.len:
        n[i] = c.semExpr(c, n[i])

proc typeBorrow(c: PContext; sym: PSym, n: PNode) =
  if n.kind in nkPragmaCallKinds and n.len == 2:
    let it = n[1]
    if it.kind != nkAccQuoted:
      localError(c.config, n.info, "a type can only borrow `.` for now")
  incl(sym.typ.flags, tfBorrowDot)

proc markCompilerProc(c: PContext; s: PSym) =
  # minor hack ahead: FlowVar is the only generic .compilerproc type which
  # should not have an external name set:
  if s.kind != skType or s.name.s != "FlowVar":
    makeExternExport(c, s, "$1", s.info)
  incl(s.flags, sfCompilerProc)
  incl(s.flags, sfUsed)
  registerCompilerProc(c.graph, s)
  if c.config.symbolFiles != disabledSf:
    addCompilerProc(c.encoder, c.packedRepr, s)

proc deprecatedStmt(c: PContext; outerPragma: PNode) =
  let pragma = outerPragma[1]
  if pragma.kind in {nkStrLit..nkTripleStrLit}:
    incl(c.module.flags, sfDeprecated)
    c.module.constraint = getStrLitNode(c, outerPragma)
    return
  if pragma.kind != nkBracket:
    localError(c.config, pragma.info, "list of key:value pairs expected"); return
  message(c.config, pragma.info, warnDeprecated,
    "deprecated statement is now a no-op, use regular deprecated pragma")

proc pragmaGuard(c: PContext; it: PNode; kind: TSymKind): PSym =
  if it.kind notin nkPragmaCallKinds or it.len != 2:
    invalidPragma(c, it); return
  let n = it[1]
  if n.kind == nkSym:
    result = n.sym
  elif kind == skField:
    # First check if the guard is a global variable:
    result = qualifiedLookUp(c, n, {})
    if result.isNil or result.kind notin {skLet, skVar} or
        sfGlobal notin result.flags:
      # We return a dummy symbol; later passes over the type will repair it.
      # Generic instantiation needs to know about this too. But we're lazy
      # and perform the lookup on demand instead.
      result = newSym(skUnknown, considerQuotedIdent(c, n), c.idgen, nil, n.info,
        c.config.options)
  else:
    result = qualifiedLookUp(c, n, {checkUndeclared})

proc semCustomPragma(c: PContext, n: PNode, sym: PSym): PNode =
  var callNode: PNode

  if n.kind in {nkIdent, nkSym}:
    # pragma -> pragma()
    callNode = newTree(nkCall, n)
  elif n.kind == nkExprColonExpr:
    # pragma: arg -> pragma(arg)
    callNode = newTree(nkCall, n[0], n[1])
  elif n.kind in nkPragmaCallKinds:
    callNode = n
  else:
    invalidPragma(c, n)
    return n

  let r = c.semOverloadedCall(c, callNode, n, {skTemplate}, {efNoUndeclared})
  if r.isNil or sfCustomPragma notin r[0].sym.flags:
    invalidPragma(c, n)
    return n

  # we have a valid custom pragma
  if sym != nil and sym.kind in {skEnumField, skForVar, skModule}:
    illegalCustomPragma(c, n, sym)
    return n

  result = r
  # Transform the nkCall node back to its original form if possible
  if n.kind == nkIdent and r.len == 1:
    # pragma() -> pragma
    result = result[0]
  elif n.kind == nkExprColonExpr and r.len == 2:
    # pragma(arg) -> pragma: arg
    result.transitionSonsKind(n.kind)

proc processEffectsOf(c: PContext, n: PNode; owner: PSym) =
  proc processParam(c: PContext; n: PNode) =
    let r = c.semExpr(c, n)
    if r.kind == nkSym and r.sym.kind == skParam:
      if r.sym.owner == owner:
        incl r.sym.flags, sfEffectsDelayed
      else:
        localError(c.config, n.info, errGenerated, "parameter cannot be declared as .effectsOf")
    else:
      localError(c.config, n.info, errGenerated, "parameter name expected")

  if n.kind notin nkPragmaCallKinds or n.len != 2:
    localError(c.config, n.info, errGenerated, "parameter name expected")
  else:
    let it = n[1]
    if it.kind in {nkCurly, nkBracket}:
      for x in items(it): processParam(c, x)
    else:
      processParam(c, it)

proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
                  validPragmas: TSpecialWords,
                  comesFromPush, isStatement: bool): bool =
  result = false
  var it = n[i]
  let keyDeep = it.kind in nkPragmaCallKinds and it.len > 1
  var key = if keyDeep: it[0] else: it
  if key.kind == nkBracketExpr:
    processNote(c, it)
    return
  elif key.kind == nkCast:
    if comesFromPush:
      localError(c.config, n.info, "a 'cast' pragma cannot be pushed")
    elif not isStatement:
      localError(c.config, n.info, "'cast' pragma only allowed in a statement context")
    case whichPragma(key[1])
    of wRaises, wTags, wForbids: pragmaRaisesOrTags(c, key[1])
    else: discard
    return
  elif key.kind notin nkIdentKinds:
    n[i] = semCustomPragma(c, it, sym)
    return
  let ident = considerQuotedIdent(c, key)
  var userPragma = strTableGet(c.userPragmas, ident)
  if userPragma != nil:
    styleCheckUse(c, key.info, userPragma)

    # number of pragmas increase/decrease with user pragma expansion
    inc c.instCounter
    if c.instCounter > 100:
      globalError(c.config, it.info, "recursive dependency: " & userPragma.name.s)

    if keyDeep:
      localError(c.config, it.info, "user pragma cannot have arguments")

    pragma(c, sym, userPragma.ast, validPragmas, isStatement)
    n.sons[i..i] = userPragma.ast.sons # expand user pragma with its content
    i.inc(userPragma.ast.len - 1) # inc by -1 is ok, user pragmas was empty
    dec c.instCounter
  else:
    let k = whichKeyword(ident)
    if k in validPragmas:
      checkPragmaUse(c, key.info, k, ident.s, (if sym != nil: sym else: c.module))
      case k
      of wExportc, wExportCpp:
        makeExternExport(c, sym, getOptionalStr(c, it, "$1"), it.info)
        if k == wExportCpp:
          if c.config.backend != backendCpp:
            localError(c.config, it.info, "exportcpp requires `cpp` backend, got: " & $c.config.backend)
          else:
            incl(sym.flags, sfMangleCpp)
        incl(sym.flags, sfUsed) # avoid wrong hints
      of wImportc:
        let name = getOptionalStr(c, it, "$1")
        cppDefine(c.config, name)
        recordPragma(c, it, "cppdefine", name)
        makeExternImport(c, sym, name, it.info)
      of wImportCompilerProc:
        let name = getOptionalStr(c, it, "$1")
        cppDefine(c.config, name)
        recordPragma(c, it, "cppdefine", name)
        processImportCompilerProc(c, sym, name, it.info)
      of wExtern: setExternName(c, sym, expectStrLit(c, it), it.info)
      of wDirty:
        if sym.kind == skTemplate: incl(sym.flags, sfDirty)
        else: invalidPragma(c, it)
      of wRedefine:
        if sym.kind == skTemplate: incl(sym.flags, sfTemplateRedefinition)
        else: invalidPragma(c, it)
      of wCallsite:
        if sym.kind == skTemplate: incl(sym.flags, sfCallsite)
        else: invalidPragma(c, it)
      of wImportCpp:
        processImportCpp(c, sym, getOptionalStr(c, it, "$1"), it.info)
      of wCppNonPod:
        incl(sym.flags, sfCppNonPod)
      of wImportJs:
        if c.config.backend != backendJs:
          localError(c.config, it.info, "`importjs` pragma requires the JavaScript target")
        let name = getOptionalStr(c, it, "$1")
        incl(sym.flags, sfImportc)
        incl(sym.flags, sfInfixCall)
        if sym.kind in skProcKinds and {'(', '#', '@'} notin name:
          localError(c.config, n.info, "`importjs` for routines requires a pattern")
        setExternName(c, sym, name, it.info)
      of wImportObjC:
        processImportObjC(c, sym, getOptionalStr(c, it, "$1"), it.info)
      of wSize:
        if sym.typ == nil: invalidPragma(c, it)
        var size = expectIntLit(c, it)
        case size
        of 1, 2, 4:
          sym.typ.size = size
          sym.typ.align = int16 size
        of 8:
          sym.typ.size = 8
          sym.typ.align = floatInt64Align(c.config)
        else:
          localError(c.config, it.info, "size may only be 1, 2, 4 or 8")
      of wAlign:
        let alignment = expectIntLit(c, it)
        if isPowerOfTwo(alignment) and alignment > 0:
          sym.alignment = max(sym.alignment, alignment)
        else:
          localError(c.config, it.info, "power of two expected")
      of wNodecl:
        noVal(c, it)
        incl(sym.loc.flags, lfNoDecl)
      of wPure, wAsmNoStackFrame:
        noVal(c, it)
        if sym != nil:
          if k == wPure and sym.kind in routineKinds: invalidPragma(c, it)
          else: incl(sym.flags, sfPure)
      of wVolatile:
        noVal(c, it)
        incl(sym.flags, sfVolatile)
      of wCursor:
        noVal(c, it)
        incl(sym.flags, sfCursor)
      of wRegister:
        noVal(c, it)
        incl(sym.flags, sfRegister)
      of wNoalias:
        noVal(c, it)
        incl(sym.flags, sfNoalias)
      of wEffectsOf:
        processEffectsOf(c, it, sym)
      of wThreadVar:
        noVal(c, it)
        incl(sym.flags, {sfThread, sfGlobal})
      of wDeadCodeElimUnused:
        warningDeprecated(c.config, n.info, "'{.deadcodeelim: on.}' is deprecated, now a noop")  # deprecated, dead code elim always on
      of wNoForward: pragmaNoForward(c, it)
      of wReorder: pragmaNoForward(c, it, flag = sfReorder)
      of wMagic: processMagic(c, it, sym)
      of wCompileTime:
        noVal(c, it)
        if comesFromPush:
          if sym.kind in {skProc, skFunc}:
            incl(sym.flags, sfCompileTime)
        else:
          incl(sym.flags, sfCompileTime)
        #incl(sym.loc.flags, lfNoDecl)
      of wGlobal:
        noVal(c, it)
        incl(sym.flags, sfGlobal)
        incl(sym.flags, sfPure)
      of wConstructor:
        incl(sym.flags, sfConstructor)
        if sfImportc notin sym.flags:
          sym.constraint = newEmptyStrNode(c, it, getOptionalStr(c, it, ""))
          sym.constraint.strVal = sym.constraint.strVal
          sym.flags.incl {sfExportc, sfMangleCpp}
          sym.typ.callConv = ccNoConvention
      of wHeader:
        var lib = getLib(c, libHeader, getStrLitNode(c, it))
        addToLib(lib, sym)
        incl(sym.flags, sfImportc)
        incl(sym.loc.flags, lfHeader)
        incl(sym.loc.flags, lfNoDecl)
        # implies nodecl, because otherwise header would not make sense
        if sym.loc.r == "": sym.loc.r = rope(sym.name.s)
      of wNoSideEffect:
        noVal(c, it)
        if sym != nil:
          incl(sym.flags, sfNoSideEffect)
          if sym.typ != nil: incl(sym.typ.flags, tfNoSideEffect)
      of wSideEffect:
        noVal(c, it)
        incl(sym.flags, sfSideEffect)
      of wNoreturn:
        noVal(c, it)
        # Disable the 'noreturn' annotation when in the "Quirky Exceptions" mode!
        if c.config.exc != excQuirky:
          incl(sym.flags, sfNoReturn)
        if sym.typ[0] != nil:
          localError(c.config, sym.ast[paramsPos][0].info,
            ".noreturn with return type not allowed")
      of wNoDestroy:
        noVal(c, it)
        incl(sym.flags, sfGeneratedOp)
      of wNosinks:
        noVal(c, it)
        incl(sym.flags, sfWasForwarded)
      of wDynlib:
        processDynLib(c, it, sym)
      of wCompilerProc, wCore:
        noVal(c, it)           # compilerproc may not get a string!
        cppDefine(c.graph.config, sym.name.s)
        recordPragma(c, it, "cppdefine", sym.name.s)
        if sfFromGeneric notin sym.flags: markCompilerProc(c, sym)
      of wNonReloadable:
        sym.flags.incl sfNonReloadable
      of wProcVar:
        # old procvar annotation, no longer needed
        noVal(c, it)
      of wExplain:
        sym.flags.incl sfExplain
      of wDeprecated:
        if sym != nil and sym.kind in routineKinds + {skType, skVar, skLet, skConst}:
          if it.kind in nkPragmaCallKinds: discard getStrLitNode(c, it)
          incl(sym.flags, sfDeprecated)
        elif sym != nil and sym.kind != skModule:
          # We don't support the extra annotation field
          if it.kind in nkPragmaCallKinds:
            localError(c.config, it.info, "annotation to deprecated not supported here")
          incl(sym.flags, sfDeprecated)
        # At this point we're quite sure this is a statement and applies to the
        # whole module
        elif it.kind in nkPragmaCallKinds: deprecatedStmt(c, it)
        else: incl(c.module.flags, sfDeprecated)
      of wVarargs:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
        else: incl(sym.typ.flags, tfVarargs)
      of wBorrow:
        if sym.kind == skType:
          typeBorrow(c, sym, it)
        else:
          noVal(c, it)
          incl(sym.flags, sfBorrow)
      of wFinal:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
        else: incl(sym.typ.flags, tfFinal)
      of wInheritable:
        noVal(c, it)
        if sym.typ == nil or tfFinal in sym.typ.flags: invalidPragma(c, it)
        else: incl(sym.typ.flags, tfInheritable)
      of wPackage:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
        else: incl(sym.flags, sfForward)
      of wAcyclic:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
        else: incl(sym.typ.flags, tfAcyclic)
      of wShallow:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
        else: incl(sym.typ.flags, tfShallow)
      of wThread:
        noVal(c, it)
        incl(sym.flags, sfThread)
        if sym.typ != nil:
          incl(sym.typ.flags, tfThread)
          if sym.typ.callConv == ccClosure: sym.typ.callConv = ccNimCall
      of wSendable:
        noVal(c, it)
        if sym != nil and sym.typ != nil:
          incl(sym.typ.flags, tfSendable)
        else:
          invalidPragma(c, it)
      of wGcSafe:
        noVal(c, it)
        if sym != nil:
          if sym.kind != skType: incl(sym.flags, sfThread)
          if sym.typ != nil: incl(sym.typ.flags, tfGcSafe)
          else: invalidPragma(c, it)
        else:
          discard "no checking if used as a code block"
      of wPacked:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
        else: incl(sym.typ.flags, tfPacked)
      of wHint:
        let s = expectStrLit(c, it)
        recordPragma(c, it, "hint", s)
        message(c.config, it.info, hintUser, s)
      of wWarning:
        let s = expectStrLit(c, it)
        recordPragma(c, it, "warning", s)
        message(c.config, it.info, warnUser, s)
      of wError:
        if sym != nil and (sym.isRoutine or sym.kind == skType) and not isStatement:
          # This is subtle but correct: the error *statement* is only
          # allowed when 'wUsed' is not in validPragmas. Here this is the easiest way to
          # distinguish properly between
          # ``proc p() {.error}`` and ``proc p() = {.error: "msg".}``
          if it.kind in nkPragmaCallKinds: discard getStrLitNode(c, it)
          incl(sym.flags, sfError)
          excl(sym.flags, sfForward)
        else:
          let s = expectStrLit(c, it)
          recordPragma(c, it, "error", s)
          localError(c.config, it.info, errUser, s)
      of wFatal: fatal(c.config, it.info, expectStrLit(c, it))
      of wDefine: processDefine(c, it, sym)
      of wUndef: processUndef(c, it)
      of wCompile: processCompile(c, it)
      of wLink: processLink(c, it)
      of wPassl:
        let s = expectStrLit(c, it)
        extccomp.addLinkOption(c.config, s)
        recordPragma(c, it, "passl", s)
      of wPassc:
        let s = expectStrLit(c, it)
        extccomp.addCompileOption(c.config, s)
        recordPragma(c, it, "passc", s)
      of wLocalPassc:
        assert sym != nil and sym.kind == skModule
        let s = expectStrLit(c, it)
        appendToModule(sym, n)
        extccomp.addLocalCompileOption(c.config, s, toFullPathConsiderDirty(c.config, sym.info.fileIndex))
        recordPragma(c, it, "localpassl", s)
      of wPush:
        processPush(c, n, i + 1)
        result = true
      of wPop:
        processPop(c, it)
        result = true
      of wPragma:
        if not sym.isNil and sym.kind == skTemplate:
          sym.flags.incl sfCustomPragma
        else:
          processPragma(c, n, i)
          result = true
      of wDiscardable:
        noVal(c, it)
        if sym != nil: incl(sym.flags, sfDiscardable)
      of wNoInit:
        noVal(c, it)
        if sym != nil: incl(sym.flags, sfNoInit)
      of wCodegenDecl: processCodegenDecl(c, it, sym)
      of wChecks, wObjChecks, wFieldChecks, wRangeChecks, wBoundChecks,
         wOverflowChecks, wNilChecks, wAssertions, wWarnings, wHints,
         wLineDir, wOptimization, wStaticBoundchecks, wStyleChecks,
         wCallconv, wDebugger, wProfiler,
         wFloatChecks, wNanChecks, wInfChecks, wPatterns, wTrMacros:
        processOption(c, it, c.config.options)
      of wStackTrace, wLineTrace:
        if sym.kind in {skProc, skMethod, skConverter}:
          processOption(c, it, sym.options)
        else:
          processOption(c, it, c.config.options)
      of FirstCallConv..LastCallConv:
        assert(sym != nil)
        if sym.typ == nil: invalidPragma(c, it)
        else:
          sym.typ.callConv = wordToCallConv(k)
          sym.typ.flags.incl tfExplicitCallConv
      of wEmit: pragmaEmit(c, it)
      of wUnroll: pragmaUnroll(c, it)
      of wLinearScanEnd, wComputedGoto: noVal(c, it)
      of wEffects:
        # is later processed in effect analysis:
        noVal(c, it)
      of wIncompleteStruct:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
        else: incl(sym.typ.flags, tfIncompleteStruct)
      of wCompleteStruct:
        noVal(c, it)
        if sym.typ == nil: invalidPragma(c, it)
        else: incl(sym.typ.flags, tfCompleteStruct)
      of wUnchecked:
        noVal(c, it)
        if sym.typ == nil or sym.typ.kind notin {tyArray, tyUncheckedArray}:
          invalidPragma(c, it)
        else:
          sym.typ.kind = tyUncheckedArray
      of wUnion:
        if c.config.backend == backendJs:
          localError(c.config, it.info, "`{.union.}` is not implemented for js backend.")
        else:
          noVal(c, it)
          if sym.typ == nil: invalidPragma(c, it)
          else: incl(sym.typ.flags, tfUnion)
      of wRequiresInit:
        noVal(c, it)
        if sym.kind == skField:
          sym.flags.incl sfRequiresInit
        elif sym.typ != nil:
          incl(sym.typ.flags, tfNeedsFullInit)
        else:
          invalidPragma(c, it)
      of wByRef:
        noVal(c, it)
        if sym != nil and sym.kind == skParam:
          sym.options.incl optByRef
        elif sym == nil or sym.typ == nil:
          processOption(c, it, c.config.options)
        else:
          incl(sym.typ.flags, tfByRef)
      of wByCopy:
        noVal(c, it)
        if sym.kind == skParam:
          incl(sym.flags, sfByCopy)
        elif sym.kind != skType or sym.typ == nil: invalidPragma(c, it)
        else: incl(sym.typ.flags, tfByCopy)
      of wPartial:
        noVal(c, it)
        if sym.kind != skType or sym.typ == nil: invalidPragma(c, it)
        else:
          incl(sym.typ.flags, tfPartial)
      of wInject, wGensym:
        # We check for errors, but do nothing with these pragmas otherwise
        # as they are handled directly in 'evalTemplate'.
        noVal(c, it)
        if sym == nil: invalidPragma(c, it)
      of wLine: pragmaLine(c, it)
      of wRaises, wTags, wForbids: pragmaRaisesOrTags(c, it)
      of wLocks:
        if sym == nil: pragmaLockStmt(c, it)
        elif sym.typ == nil: invalidPragma(c, it)
        else: warningDeprecated(c.config, n.info, "'Lock levels' are deprecated, now a noop")
      of wBitsize:
        if sym == nil or sym.kind != skField:
          invalidPragma(c, it)
        else:
          sym.bitsize = expectIntLit(c, it)
          if sym.bitsize <= 0:
            localError(c.config, it.info, "bitsize needs to be positive")
      of wGuard:
        if sym == nil or sym.kind notin {skVar, skLet, skField}:
          invalidPragma(c, it)
        else:
          sym.guard = pragmaGuard(c, it, sym.kind)
      of wGoto:
        if sym == nil or sym.kind notin {skVar, skLet}:
          invalidPragma(c, it)
        else:
          sym.flags.incl sfGoto
      of wExportNims:
        if sym == nil: invalidPragma(c, it)
        else: magicsys.registerNimScriptSymbol(c.graph, sym)
      of wExperimental:
        if not isTopLevel(c):
          localError(c.config, n.info, "'experimental' pragma only valid as toplevel statement or in a 'push' environment")
        processExperimental(c, it)
      of wDoctype:
        if not isTopLevel(c):
          localError(c.config, n.info, "\"doctype\" pragma only valid as top-level statement")
      of wNoRewrite:
        noVal(c, it)
      of wBase:
        noVal(c, it)
        sym.flags.incl sfBase
      of wIntDefine:
        processDefineConst(c, n, sym, mIntDefine)
      of wStrDefine:
        processDefineConst(c, n, sym, mStrDefine)
      of wBoolDefine:
        processDefineConst(c, n, sym, mBoolDefine)
      of wUsed:
        noVal(c, it)
        if sym == nil: invalidPragma(c, it)
        else: sym.flags.incl sfUsed
      of wLiftLocals: discard
      of wRequires, wInvariant, wAssume, wAssert:
        pragmaProposition(c, it)
      of wEnsures:
        pragmaEnsures(c, it)
      of wEnforceNoRaises, wQuirky:
        sym.flags.incl sfNeverRaises
      of wSystemRaisesDefect:
        sym.flags.incl sfSystemRaisesDefect
      of wVirtual:
        processVirtual(c, it, sym, sfVirtual)
      of wMember:
        processVirtual(c, it, sym, sfMember)

      else: invalidPragma(c, it)
    elif comesFromPush and whichKeyword(ident) != wInvalid:
      discard "ignore the .push pragma; it doesn't apply"
    else:
      # semCustomPragma gives appropriate error for invalid pragmas
      n[i] = semCustomPragma(c, it, sym)

proc overwriteLineInfo(n: PNode; info: TLineInfo) =
  n.info = info
  for i in 0..<n.safeLen:
    overwriteLineInfo(n[i], info)

proc mergePragmas(n, pragmas: PNode) =
  var pragmas = copyTree(pragmas)
  overwriteLineInfo pragmas, n.info
  if n[pragmasPos].kind == nkEmpty:
    n[pragmasPos] = pragmas
  else:
    for p in pragmas: n[pragmasPos].add p

proc implicitPragmas*(c: PContext, sym: PSym, info: TLineInfo,
                      validPragmas: TSpecialWords) =
  if sym != nil and sym.kind != skModule:
    for it in c.optionStack:
      let o = it.otherPragmas
      if not o.isNil:
        pushInfoContext(c.config, info)
        var i = 0
        while i < o.len:
          if singlePragma(c, sym, o, i, validPragmas, true, false):
            internalError(c.config, info, "implicitPragmas")
          inc i
        popInfoContext(c.config)
        if sym.kind in routineKinds and sym.ast != nil: mergePragmas(sym.ast, o)

    if lfExportLib in sym.loc.flags and sfExportc notin sym.flags:
      localError(c.config, info, ".dynlib requires .exportc")
    var lib = c.optionStack[^1].dynlib
    if {lfDynamicLib, lfHeader} * sym.loc.flags == {} and
        sfImportc in sym.flags and lib != nil:
      incl(sym.loc.flags, lfDynamicLib)
      addToLib(lib, sym)
      if sym.loc.r == "": sym.loc.r = rope(sym.name.s)

proc hasPragma*(n: PNode, pragma: TSpecialWord): bool =
  if n == nil: return false

  for p in n:
    var key = if p.kind in nkPragmaCallKinds and p.len > 1: p[0] else: p
    if key.kind == nkIdent and whichKeyword(key.ident) == pragma:
      return true

  return false

proc pragmaRec(c: PContext, sym: PSym, n: PNode, validPragmas: TSpecialWords;
               isStatement: bool) =
  if n == nil: return
  var i = 0
  while i < n.len:
    if singlePragma(c, sym, n, i, validPragmas, false, isStatement): break
    inc i

proc pragma(c: PContext, sym: PSym, n: PNode, validPragmas: TSpecialWords;
            isStatement: bool) =
  if n == nil: return
  pragmaRec(c, sym, n, validPragmas, isStatement)
  # XXX: in the case of a callable def, this should use its info
  implicitPragmas(c, sym, n.info, validPragmas)

proc pragmaCallable*(c: PContext, sym: PSym, n: PNode, validPragmas: TSpecialWords,
                    isStatement: bool = false) =
  if n == nil: return
  if n[pragmasPos].kind != nkEmpty:
    pragmaRec(c, sym, n[pragmasPos], validPragmas, isStatement)