Nim/compiler/cgen.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 the C code generator.

import
  ast, astalgo, trees, platform, magicsys, extccomp, options,
  nversion, nimsets, msgs, bitsets, idents, types,
  ccgutils, ropes, wordrecg, treetab, cgmeth,
  rodutils, renderer, cgendata, aliases,
  lowerings, lineinfos, pathutils, transf,
  injectdestructors, astmsgs, modulepaths, pushpoppragmas,
  mangleutils, cbuilderbase, modulegraphs, icprof

from expanddefaults import caseObjDefaultBranch
from ast2nif import globalName, toNifFilename, icNifTypeName
from typekeys import modname
from std/algorithm import sort
import cnif

import pipelineutils

when defined(nimPreviewSlimSystem):
  import std/assertions

when not defined(leanCompiler):
  import spawn, semparallel

import std/strutils except `%`, addf # collides with ropes.`%`

import std/[dynlib, math, tables, sets, os, intsets, hashes]

const
  # we use some ASCII control characters to insert directives that will be converted to real code in a postprocessing pass
  postprocessDirStart = '\1'
  postprocessDirSep = '\31'
  postprocessDirEnd = '\23'

when not declared(dynlib.libCandidates):
  proc libCandidates(s: string, dest: var seq[string]) =
    ## given a library name pattern `s` write possible library names to `dest`.
    var le = strutils.find(s, '(')
    var ri = strutils.find(s, ')', le+1)
    if le >= 0 and ri > le:
      var prefix = substr(s, 0, le - 1)
      var suffix = substr(s, ri + 1)
      for middle in split(substr(s, le + 1, ri - 1), '|'):
        libCandidates(prefix & middle & suffix, dest)
    else:
      dest.add(s)

when defined(tinyc): # == hasTinyCBackend; spelled out for the IC dep scanner
  import tccgen

proc hcrOn(m: BModule): bool = m.config.hcrOn
proc hcrOn(p: BProc): bool = p.module.config.hcrOn

proc addForwardedProc(m: BModule, prc: PSym) =
  m.g.forwardedProcs.add(prc)

proc newModule*(g: BModuleList; module: PSym; conf: ConfigRef; idgen: IdGenerator): BModule
proc getCFile*(m: BModule): AbsoluteFile

proc ownerModule(m: BModule; s: PSym): BModule =
  ## The BModule of `s`'s own module, created on demand. A NIF backend loads
  ## modules lazily, so the owner may have no BModule yet even though the symbol
  ## resolved.
  var ms = getModule(s)
  registerModule m.g.graph, ms
  if ms.position >= m.g.mods.len:
    result = newModule(m.g, ms, m.config, idGeneratorForBackend(ms))
  else:
    result = m.g.mods[ms.position]
    if result == nil:
      result = newModule(m.g, ms, m.config, idGeneratorForBackend(ms))

proc findPendingModule(m: BModule, s: PSym): BModule =
  if m.config.cmd == cmdNifC and m.config.icBackendStage == "cg":
    # Per-module backend codegen. `m.g.icEmitted` is the set of modules THIS
    # process writes a TU for, so it — not the identity of whichever TU happened
    # to demand `s` — decides where the definition goes:
    #
    # * owner in `icEmitted`: this process is writing that module's TU, so the
    #   definition belongs in it and nowhere else. That is the ordinary
    #   whole-program routing below, and honouring it is what lets one process
    #   emit SEVERAL modules without their definitions collapsing into the first
    #   TU to ask for them. With the set at its current size of one, the owner
    #   IS `m` and this returns exactly what the old unconditional `return m`
    #   did — the point of the branch is that it stops being a special case.
    #
    # * owner elsewhere: the module is not written in this process, so the
    #   definition has nowhere else to go and is emitted here as well
    #   (emit-everywhere). The process that owns it emits it too; `merge` keeps
    #   one per C name and turns the rest into prototypes, which already live in
    #   the unmarked protos section.
    #
    # `getModule` walks the owner chain and yields nil if it never reaches a
    # module (backend-minted symbols can be parented outside one), which is a
    # definition with no owning TU: emit it here.
    let ms = getModule(s)
    if ms != nil and ms.kind == skModule and m.g.icEmitted.contains(ms.position):
      return ownerModule(m, s)
    return m
  if m.config.symbolFiles == v2Sf or optCompress in m.config.globalOptions:
    let ms = s.itemId.module  #getModule(s)
    result = m.g.mods[ms]
  elif m.config.cmd in {cmdNifC, cmdM}:
    result = ownerModule(m, s)
  else:
    var ms = getModule(s)
    result = m.g.mods[ms.position]

proc icNifName(m: BModule; s: PSym): string =
  ## The serialized NIF name of `s`, recorded next to its C name in the cnif
  ## artifact so a later run can re-demand the definition when a reused TU
  ## still references it (the def-retention check). Backend-minted symbols
  ## have no NIF name.
  if m.config.cmd == cmdNifC and s != nil and not isBackendMinted(s.itemId):
    result = globalName(s, m.config)
  else:
    result = ""

proc icNifName(m: BModule; t: PType): string =
  ## The type flavor: recorded next to RTTI data definitions so the
  ## def-retention check can re-demand the typeinfo of a regenerating TU's
  ## previous artifact (`genTypeInfo` is type-driven, not symbol-driven).
  if m.config.cmd == cmdNifC:
    result = icNifTypeName(t, m.config)
  else:
    result = ""


proc signatureHasMetaType*(t: PType; depth: int = 0): bool =
  ## Whether a routine signature mentions a compile-time/meta element type
  ## (`typed`/`untyped` — e.g. `echo`'s `varargs[typed]` — typedesc, static,
  ## generic param). Such routines are expanded at their call sites and never
  ## emitted standalone, so the per-module owned-routine seeding must skip them
  ## (`getTypeDescAux(tyTyped)` otherwise). `tfHasMeta` alone misses the varargs
  ## element case, hence the explicit scan.
  result = false
  if t == nil or depth > 8: return false
  if t.kind == tyGenericBody:
    # The uninstantiated template carried as a `tyGenericInst`'s first child
    # always mentions its `tyGenericParam` placeholders, but the instance
    # itself is fully concrete (e.g. `var CountTable[SigHash]`). Descending
    # here would wrongly flag every routine with a generic-instance parameter
    # as meta and drop it from the owned-routine seeding -> undefined symbols
    # at link (its only definer never emits it).
    return false
  if t.kind == tyStatic:
    # A RESOLVED static value (the `256` in `MDigest[256]`, the `N` in
    # `HashList[T, N]`, …) is carried as a `tyStatic` node inside the otherwise
    # fully-concrete `tyGenericInst`, but it is NOT meta: the routine is a normal
    # runtime routine the owner must emit. Only an UNRESOLVED `static T` parameter
    # (no bound value, `t.n == nil`) is meta. Without this, every routine whose
    # signature touches a `static`-parameterized generic instance (the bulk of
    # the SSZ/`MDigest` API) is dropped from the owned-routine seeding and ends up
    # an undefined reference at link (mirrors the tyGenericBody case above).
    return t.n == nil
  if t.kind in {tyTyped, tyUntyped, tyTypeDesc, tyGenericParam,
                tyAnything, tyFromExpr, tyError}:
    return true
  for k in t.kids:
    if signatureHasMetaType(k, depth + 1): return true

proc ownsRuntimeRoutine*(s: PSym; modPos: int): bool =
  ## A concrete, non-generic, runtime routine with a real body, OWNED by the
  ## module at `modPos`. Shared by the `cg` stage's owned-routine seeding (so a
  ## routine called only from other modules is still emitted by somebody) and
  ## the `lower` stage's owned-routine enumeration, so both stages see exactly
  ## the same set. The exclusions:
  ## - nested/closure procs (owner is a proc, not a module): emitted via their
  ##   enclosing routine's lambda-lifting, never standalone;
  ## - generic instances (`sfFromGeneric`): emitted by demand, deduped by merge;
  ## - `importc`/`compileTime`/`error`/forward sentinels and meta signatures:
  ##   not real codegen targets.
  ## - method DISPATCHERS (`sfDispatcher`): their bodies are (re)synthesized into
  ##   the main TU by `emitMethodDispatchers`/`generateIfMethodDispatchers`, never
  ##   per module. A dispatcher is a `copySym` clone of the method that shares the
  ##   method's body sub-tree (incl. its closure iterator); transforming it here
  ##   would lambda-lift that SHARED iterator a SECOND time under a different owner
  ##   identity, baking a conflicting `up` field → "up references do not agree"
  ##   (the divergence is impossible in non-IC, where the dispatcher body is empty
  ##   at lift time). So a dispatcher is never an owned runtime routine.
  ## A `{.closure.}` iterator IS a standalone runtime routine (unlike an inline
  ## iterator, which is expanded at each call site) and must be emitted by its
  ## owner — else a cross-module `for` over it links to nothing.
  ##
  ## Generic INSTANCES (`sfFromGeneric`) are NEVER an owned runtime routine — not
  ## in `cg` and not in the `lower` stage. They are demanded by the backend's
  ## emit-everywhere path and deduped by `merge` (content C name); the frontend
  ## materialises them through the `(offer)` mechanism. The `lower` stage must
  ## not transform an instance: a not-fully-concrete instance (a closure factory
  ## over a `static` param, or a `$`/`=` op instance whose body resolves only at
  ## its further-specialised use sites) still carries unresolved overload choices
  ## and crashes `transformBody` (empty-`namePos` lambda, nil-typed const-fold).
  s.itemId.module == modPos and
  (s.kind in {skProc, skFunc, skConverter, skMethod} or
   (s.kind == skIterator and s.typ != nil and s.typ.callConv == ccClosure)) and
  s.skipGenericOwner != nil and s.skipGenericOwner.kind == skModule and
  s.magic == mNone and
  sfFromGeneric notin s.flags and
  sfDispatcher notin s.flags and
  {sfForward, sfImportc, sfCompileTime, sfError} * s.flags == {} and
  s.typ != nil and not signatureHasMetaType(s.typ) and
  s.ast != nil and s.ast.safeLen > bodyPos and
  son(s.ast, genericParamsPos).kind == nkEmpty
  # NOTE: an `nkEmpty` body is NOT a disqualifier. A concrete, owned, non-
  # forward/-importc/-magic routine whose body folds to nothing is still a real
  # definition the owner must emit (`void f(void){}`), exactly as whole-program
  # cgen does — else a cross-module caller links to nothing. This bites e.g.
  # Nimbus' `extras.incInternalErrors`, a plain `proc` whose sole statement is a
  # metrics-counter `.inc()` that the `metrics` library expands to a no-op when
  # the importing tool (ncli) builds with `-u:metrics`; the body is then a bare
  # `nkEmpty`, but `state_transition_epoch` still calls it. Forward declarations
  # (the other empty-body case) carry `sfForward` and are excluded above.

proc bodyIsSeededByItsOwner(prc: PSym): bool =
  ## Whether SOME module's `cg` is guaranteed to emit `prc`'s body on its own,
  ## without this TU asking for it. There are exactly two seeders in the
  ## per-module backend, and this enumerates them:
  ##
  ##   * `nifbackend.generateCodeForModule` walks its module's index and
  ##     `requestProcDef`s every `ownsRuntimeRoutine` — the SAME predicate the
  ##     `lower` stage uses to decide what it transforms into that module's
  ##     `.t.bif`. So asking it about `prc`'s OWN defining module answers
  ##     "will that module's cg seed this?".
  ##   * `nifbackend.emitMethodDispatchers` synthesizes every method dispatcher
  ##     into the MAIN TU. A dispatcher is a `copySym` clone that no module's
  ##     index enumerates, so the first rule cannot see it.
  ##
  ## Anything else — a generic instance, a synthesized hook, a nested routine
  ## (emitted as part of its enclosing routine's lambda-lifted body), an inline
  ## iterator (expanded at each call site) — is seeded by nobody. Those are
  ## emitted by EVERY demander and `merge` keeps one per content-addressed C
  ## name. That is the single default, and it is the safe direction: emitting a
  ## body twice costs a merge dedup, while emitting it nowhere is a link error.
  ##
  ## A BACKEND-MINTED routine (a hook or nested proc that lambda-lifting /
  ## `injectDestructorCalls` created during `lower`) exists in no module's semmed
  ## NIF: it is written into the `.t.bif` of every module that references it,
  ## re-homed there with `@bk`. Its `itemId.module` therefore names whichever
  ## `.t.bif` it was read from rather than a module that seeds it, so it must not
  ## be routed through the ownership question at all.
  if isBackendMinted(prc.itemId): return false
  result = sfDispatcher in prc.flags or
           ownsRuntimeRoutine(prc, prc.itemId.module)

proc emitsBodyInThisModule(m: BModule, prc: PSym): bool =
  ## Whether the translation unit `m` emits `prc`'s BODY, as opposed to only a
  ## prototype for a body some other `cg` process emits. The funnel where the
  ## main module re-emitted its entire transitive closure (~1.8 GB, a 56 MB
  ## `.c.nif`) is exactly this rule being absent.
  ##
  ## `m` is the TU the body would go INTO — `findPendingModule`'s answer — not
  ## the one that demanded it. The two were the same module for as long as a `cg`
  ## process wrote exactly one TU, and asking with the demander was harmless.
  ## With a batch they differ, and asking with the demander is the bug: a
  ## definition routed to its owner inside the batch was marked declared there
  ## and then emitted by nobody, since the demander is not the owner and the
  ## owner never gets asked again (18 undefined symbols at link, batch size 4).
  ##
  ## The decision is a lookup against `bodyIsSeededByItsOwner`, i.e. against the
  ## very predicates that drive the seeding, rather than a re-derivation from
  ## symbol ancestry. Re-derivation is what made this function a five-clause
  ## tower and the source of a run of "emitted by nobody" / "two hooks on one C
  ## name" bugs: the walk answered a question about who WILL emit by inspecting
  ## who DECLARED, and the two drifted apart for every symbol the backend mints.
  if not (m.config.cmd == cmdNifC and m.config.icBackendStage == "cg"):
    return true
  if not bodyIsSeededByItsOwner(prc):
    # Seeded by nobody: every demander emits it, merge keeps one.
    result = true
  elif sfDispatcher in prc.flags:
    result = sfMainModule in m.module.flags
  else:
    result = prc.itemId.module == m.module.position

proc initLoc(k: TLocKind, lode: PNode, s: TStorageLoc, flags: TLocFlags = {}): TLoc =
  result = TLoc(k: k, storage: s, lode: lode,
                snippet: "", flags: flags)

proc fillLoc(a: var TLoc, k: TLocKind, lode: PNode, r: Rope, s: TStorageLoc) {.inline.} =
  # fills the loc if it is not already initialized
  if a.k == locNone:
    a.k = k
    a.lode = lode
    a.storage = s
    if a.snippet == "": a.snippet = r

proc fillLoc(a: var TLoc, k: TLocKind, lode: PNode, s: TStorageLoc) {.inline.} =
  # fills the loc if it is not already initialized
  if a.k == locNone:
    a.k = k
    a.lode = lode
    a.storage = s

proc t(a: TLoc): PType {.inline.} =
  if a.lode.kind == nkSym and a.lode.sym.typ != nil:
    result = a.lode.sym.typ
  else:
    # Under `nim ic` an object-field reference is a typeless leaf stub (its def
    # lives in another seek; see ast2nif `FieldMarker`) that carries its type on
    # the NODE instead. Fall back to the node type. Byte-neutral for non-IC, where
    # a real sym always has a type.
    result = a.lode.typ

proc lodeTyp(t: PType): PNode =
  result = newNode(nkEmpty)
  result.typ = t

proc isSimpleConst(typ: PType): bool =
  let t = skipTypes(typ, abstractVar)
  result = t.kind notin
      {tyTuple, tyObject, tyArray, tySet, tySequence} and not
      (t.kind == tyProc and t.callConv == ccClosure)

proc useHeader(m: BModule, sym: PSym) =
  if lfHeader in sym.loc.flags:
    assert(sym.annex != nil)
    let str = getStr(sym.annex.path)
    m.includeHeader(str)

proc cgsym(m: BModule, name: string)
proc cgsymValue(m: BModule, name: string): Rope

proc getModuleDllPath(m: BModule): Rope =
  let (dir, name, ext) = splitFile(getCFile(m))
  let filename = strutils.`%`(platform.OS[m.g.config.target.targetOS].dllFrmt, [name & ext])
  result = makeCString(dir.string & "/" & filename)

proc getModuleDllPath(m: BModule, module: int): Rope =
  result = getModuleDllPath(m.g.mods[module])

proc getModuleDllPath(m: BModule, s: PSym): Rope =
  result = getModuleDllPath(m.g.mods[s.itemId.module])

import std/macros

proc cgFormatValue(result: var string; value: string) =
  result.add value

proc cgFormatValue(result: var string; value: BiggestInt) =
  result.addInt value

proc cgFormatValue(result: var string; value: Int128) =
  result.addInt128 value

template addf(result: var Builder, args: varargs[untyped]) =
  result.buf.addf(args)

# TODO: please document
macro ropecg(m: BModule, frmt: static[FormatStr], args: untyped): Rope =
  args.expectKind nnkBracket
  # echo "ropecg ", newLit(frmt).repr, ", ", args.repr
  var i = 0
  result = nnkStmtListExpr.newTree()

  result.add quote do:
    assert `m` != nil

  let resVar = genSym(nskVar, "res")
  # during `koch boot` the median of all generates strings from this
  # macro is around 40 bytes in length.
  result.add newVarStmt(resVar, newCall(bindSym"newStringOfCap", newLit(80)))
  let formatValue = bindSym"cgFormatValue"

  var num = 0
  var strLit = ""

  template flushStrLit() =
    if strLit != "":
      result.add newCall(ident "add", resVar, newLit(strLit))
      strLit.setLen 0

  while i < frmt.len:
    if frmt[i] == '$':
      inc(i)                  # skip '$'
      case frmt[i]
      of '$':
        strLit.add '$'
        inc(i)
      of '#':
        flushStrLit()
        inc(i)
        result.add newCall(formatValue, resVar, args[num])
        inc(num)
      of '^':
        flushStrLit()
        inc(i)
        result.add newCall(formatValue, resVar, args[^1])
        inc(num)
      of '0'..'9':
        var j = 0
        while true:
          j = (j * 10) + ord(frmt[i]) - ord('0')
          inc(i)
          if i >= frmt.len or not (frmt[i] in {'0'..'9'}): break
        num = j
        if j > args.len:
          error("ropes: invalid format string " & newLit(frmt).repr & " args.len: " & $args.len)

        flushStrLit()
        result.add newCall(formatValue, resVar, args[j-1])
      of 'n':
        flushStrLit()
        result.add quote do:
          if optLineDir notin `m`.config.options:
            `resVar`.add("\L")
        inc(i)
      of 'N':
        strLit.add "\L"
        inc(i)
      else:
        error("ropes: invalid format string $" & frmt[i])
    elif frmt[i] == '#' and frmt[i+1] in IdentStartChars:
      inc(i)
      var j = i
      while frmt[j] in IdentChars: inc(j)
      var ident = newLit(substr(frmt, i, j-1))
      i = j
      flushStrLit()
      result.add newCall(formatValue, resVar, newCall(ident"cgsymValue", m, ident))
    elif frmt[i] == '#' and frmt[i+1] == '$':
      inc(i, 2)
      var j = 0
      while frmt[i] in Digits:
        j = (j * 10) + ord(frmt[i]) - ord('0')
        inc(i)
      let ident = args[j-1]
      flushStrLit()
      result.add newCall(formatValue, resVar, newCall(ident"cgsymValue", m, ident))
    elif frmt[i] == '#' and frmt[i+1] == '#':
      inc(i, 2)
      strLit.add("#")
    else:
      strLit.add(frmt[i])
      inc(i)

  flushStrLit()
  result.add newCall(ident"rope", resVar)

proc addIndent(p: BProc; result: var Rope) =
  var i = result.len
  let newLen = i + p.blocks.len
  result.setLen newLen
  while i < newLen:
    result[i] = '\t'
    inc i

proc addIndent(p: BProc; result: var Builder) =
  var i = result.buf.len
  let newLen = i + p.blocks.len
  result.buf.setLen newLen
  while i < newLen:
    result.buf[i] = '\t'
    inc i

template appcg(m: BModule, c: var (Rope | Builder), frmt: FormatStr,
           args: untyped) =
  c.add(ropecg(m, frmt, args))

template appcg(m: BModule, sec: TCFileSection, frmt: FormatStr,
           args: untyped) =
  m.s[sec].add(ropecg(m, frmt, args))

template appcg(p: BProc, sec: TCProcSection, frmt: FormatStr,
           args: untyped) =
  p.s(sec).add(ropecg(p.module, frmt, args))

template line(p: BProc, sec: TCProcSection, r: string) =
  addIndent p, p.s(sec)
  p.s(sec).add(r)

template lineF(p: BProc, sec: TCProcSection, frmt: FormatStr,
              args: untyped) =
  addIndent p, p.s(sec)
  p.s(sec).add(frmt % args)

template lineCg(p: BProc, sec: TCProcSection, frmt: FormatStr,
               args: untyped) =
  addIndent p, p.s(sec)
  p.s(sec).add(ropecg(p.module, frmt, args))

template linefmt(p: BProc, sec: TCProcSection, frmt: FormatStr,
             args: untyped) =
  addIndent p, p.s(sec)
  p.s(sec).add(ropecg(p.module, frmt, args))

proc safeLineNm(info: TLineInfo): int =
  result = toLinenumber(info)
  if result < 0: result = 0 # negative numbers are not allowed in #line

proc genPostprocessDir(field1, field2, field3: string): string =
  result = postprocessDirStart & field1 & postprocessDirSep & field2 & postprocessDirSep & field3 & postprocessDirEnd

proc genCLineDir(r: var Builder, fileIdx: FileIndex, line: int; conf: ConfigRef) =
  assert line >= 0
  if optLineDir in conf.options and line > 0:
    if fileIdx == InvalidFileIdx:
      r.add(rope("\n#line " & $line & " \"generated_not_to_break_here\"\n"))
    else:
      r.add(rope("\n#line " & $line & " FX_" & $fileIdx.int32 & "\n"))

proc genCLineDir(r: var Builder, fileIdx: FileIndex, line: int; p: BProc; info: TLineInfo; lastFileIndex: FileIndex) =
  assert line >= 0
  if optLineDir in p.config.options and line > 0:
    if fileIdx == InvalidFileIdx:
      r.add(rope("\n#line " & $line & " \"generated_not_to_break_here\"\n"))
    else:
      r.add(rope("\n#line " & $line & " FX_" & $fileIdx.int32 & "\n"))

proc genCLineDir(r: var Builder, info: TLineInfo; conf: ConfigRef) =
  if optLineDir in conf.options:
    genCLineDir(r, info.fileIndex, info.safeLineNm, conf)

proc freshLineInfo(p: BProc; info: TLineInfo): bool =
  if p.lastLineInfo.line != info.line or
     p.lastLineInfo.fileIndex != info.fileIndex:
    p.lastLineInfo.line = info.line
    p.lastLineInfo.fileIndex = info.fileIndex
    result = true
  else:
    result = false

proc genCLineDir(r: var Builder, p: BProc, info: TLineInfo; conf: ConfigRef) =
  if optLineDir in conf.options:
    let lastFileIndex = p.lastLineInfo.fileIndex
    if freshLineInfo(p, info):
      genCLineDir(r, info.fileIndex, info.safeLineNm, p, info, lastFileIndex)

proc genLineDir(p: BProc; t: PNode) =
  if p == p.module.preInitProc: return
  let line = t.info.safeLineNm

  if optEmbedOrigSrc in p.config.globalOptions:
    var code = sourceLine(p.config, t.info)
    if code.endsWith('\\'):
      code.add "#"
    p.s(cpsStmts).add("// " & code & "\L")
  let lastFileIndex = p.lastLineInfo.fileIndex
  let freshLine = freshLineInfo(p, t.info)
  if freshLine:
    genCLineDir(p.s(cpsStmts), t.info.fileIndex, line, p, t.info, lastFileIndex)
  if ({optLineTrace, optStackTrace} * p.options == {optLineTrace, optStackTrace}) and
      (p.prc == nil or sfPure notin p.prc.flags) and t.info.fileIndex != InvalidFileIdx:
      if freshLine:
        line(p, cpsStmts, genPostprocessDir("nimln", $line, $t.info.fileIndex.int32))

proc accessThreadLocalVar(p: BProc, s: PSym)
proc emulatedThreadVars(conf: ConfigRef): bool {.inline.}
proc genProc(m: BModule, prc: PSym)
proc raiseInstr(p: BProc; result: var Builder)

template compileToCpp(m: BModule): untyped =
  m.config.backend == backendCpp or sfCompileToCpp in m.module.flags

proc getTempName(m: BModule): Rope =
  result = m.tmpBase & rope(m.labels)
  inc m.labels

proc isNoReturn(m: BModule; s: PSym): bool {.inline.} =
  sfNoReturn in s.flags and m.config.exc != excGoto

include cbuilderexprs
include cbuilderdecls
include cbuilderstmts

proc rdLoc(a: TLoc): Rope =
  # 'read' location (deref if indirect)
  if lfIndirect in a.flags:
    result = cDeref(a.snippet)
  else:
    result = a.snippet

proc addRdLoc(a: TLoc; result: var Builder) =
  if lfIndirect in a.flags:
    result.add cDeref(a.snippet)
  else:
    result.add a.snippet

proc lenField(p: BProc, val: Rope): Rope {.inline.} =
  if p.module.compileToCpp:
    result = derefField(val, "len")
  else:
    result = dotField(derefField(val, "Sup"), "len")

proc lenExpr(p: BProc; a: TLoc): Rope =
  if optSeqDestructors in p.config.globalOptions:
    if p.config.usesSso() and a.lode != nil and a.t != nil and
        a.t.skipTypes(abstractInst).kind == tyString:
      result = cCall(cgsymValue(p.module, "nimStrLen"), rdLoc(a))
    else:
      result = dotField(rdLoc(a), "len")
  else:
    let ra = rdLoc(a)
    result = cIfExpr(ra, lenField(p, ra), cIntValue(0))

proc dataFieldAccessor(p: BProc, sym: Rope): Rope =
  if optSeqDestructors in p.config.globalOptions:
    result = dotField(wrapPar(sym), "p")
  else:
    result = sym

proc dataField(p: BProc, val: Rope): Rope {.inline.} =
  result = derefField(dataFieldAccessor(p, val), "data")

proc genProcPrototype(m: BModule, sym: PSym)

include ccgliterals
include ccgtypes

# ------------------------------ Manager of temporaries ------------------

template mapTypeChooser(n: PNode): TSymKind =
  (if n.kind == nkSym: n.sym.kind else: skVar)

template mapTypeChooser(a: TLoc): TSymKind = mapTypeChooser(a.lode)

proc addAddrLoc(conf: ConfigRef; a: TLoc; result: var Builder) =
  if lfIndirect notin a.flags and mapType(conf, a.t, mapTypeChooser(a) == skParam) != ctArray:
    result.add wrapPar(cAddr(a.snippet))
  else:
    result.add a.snippet

proc addrLoc(conf: ConfigRef; a: TLoc): Rope =
  if lfIndirect notin a.flags and mapType(conf, a.t, mapTypeChooser(a) == skParam) != ctArray:
    result = wrapPar(cAddr(a.snippet))
  else:
    result = a.snippet

proc byRefLoc(p: BProc; a: TLoc): Rope =
  if lfIndirect notin a.flags and mapType(p.config, a.t, mapTypeChooser(a) == skParam) != ctArray and not
      p.module.compileToCpp:
    result = wrapPar(cAddr(a.snippet))
  else:
    result = a.snippet

proc rdCharLoc(a: TLoc): Rope =
  # read a location that may need a char-cast:
  result = rdLoc(a)
  if skipTypes(a.t, abstractRange).kind == tyChar:
    result = cCast(NimUint8, result)

type
  TAssignmentFlag = enum
    needToCopy
    needTempForOpenArray
    needAssignCall
  TAssignmentFlags = set[TAssignmentFlag]

proc genObjConstr(p: BProc; e: PNode, d: var TLoc)
proc rawConstExpr(p: BProc; n: PNode; d: var TLoc)
proc genAssignment(p: BProc, dest, src: TLoc, flags: TAssignmentFlags)

type
  ObjConstrMode = enum
    constructObj,
    constructRefObj

proc genObjectInit(p: BProc, section: TCProcSection, t: PType, a: var TLoc,
                   mode: ObjConstrMode) =
  #if optNimV2 in p.config.globalOptions: return
  case analyseObjectWithTypeField(t)
  of frNone:
    discard
  of frHeader:
    var r = rdLoc(a)
    if mode == constructRefObj: r = cDeref(r)
    var s = skipTypes(t, abstractInst)
    if not p.module.compileToCpp:
      while s.kind == tyObject and s.baseClass != nil:
        r = dotField(r, "Sup")
        s = skipTypes(s.baseClass, skipPtrs)
    if optTinyRtti in p.config.globalOptions:
      p.s(section).addFieldAssignment(r, "m_type", genTypeInfoV2(p.module, t, a.lode.info))
    else:
      p.s(section).addFieldAssignment(r, "m_type", genTypeInfoV1(p.module, t, a.lode.info))
  of frEmbedded:
    if optTinyRtti in p.config.globalOptions:
      var tmp: TLoc = default(TLoc)
      if mode == constructRefObj:
        let objType = t.skipTypes(abstractInst+{tyRef})
        rawConstExpr(p, newNodeIT(nkType, a.lode.info, objType), tmp)
        let ra = rdLoc(a)
        let rtmp = rdLoc(tmp)
        let rt = getTypeDesc(p.module, objType, descKindFromSymKind mapTypeChooser(a))
        p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimCopyMem"),
          cCast(CPointer, ra),
          cCast(CConstPointer, cAddr(rtmp)),
          cSizeof(rt))
      else:
        rawConstExpr(p, newNodeIT(nkType, a.lode.info, t), tmp)
        genAssignment(p, a, tmp, {})
    else:
      # worst case for performance:
      var r = if mode == constructObj: addrLoc(p.config, a) else: rdLoc(a)
      p.s(section).addCallStmt(cgsymValue(p.module, "objectInit"),
        r,
        genTypeInfoV1(p.module, t, a.lode.info))

  if isException(t):
    var r = rdLoc(a)
    if mode == constructRefObj: r = cDeref(r)
    var s = skipTypes(t, abstractInst)
    if not p.module.compileToCpp:
      while s.kind == tyObject and s.baseClass != nil and s.sym.magic != mException:
        r = dotField(r, "Sup")
        s = skipTypes(s.baseClass, skipPtrs)
    p.s(section).addFieldAssignment(r, "name", makeCString(t.skipTypes(abstractInst).sym.name.s))

proc genRefAssign(p: BProc, dest, src: TLoc)

proc isComplexValueType(t: PType): bool {.inline.} =
  let t = t.skipTypes(abstractInst + tyUserTypeClasses)
  result = t.kind in {tyArray, tySet, tyTuple, tyObject, tyOpenArray} or
    (t.kind == tyProc and t.callConv == ccClosure)

include ccgreset

proc resetLoc(p: BProc, loc: var TLoc) =
  let containsGcRef = optSeqDestructors notin p.config.globalOptions and containsGarbageCollectedRef(loc.t)
  let typ = skipTypes(loc.t, abstractVarRange)
  if isImportedCppType(typ):
    var didGenTemp = false
    let rl = rdLoc(loc)
    let init = genCppConstructorExpr(p.module, p, typ, didGenTemp)
    p.s(cpsStmts).addAssignment(rl, init)
    return
  if optSeqDestructors in p.config.globalOptions and typ.kind in {tyString, tySequence}:
    assert loc.snippet != ""

    let atyp = skipTypes(loc.t, abstractInst)
    let rl = rdLoc(loc)
    if typ.kind == tyString and p.config.usesSso():
      # SmallString zero state: bytes=0 (slen=0 in low byte, all inline chars zeroed)
      if atyp.kind in {tyVar, tyLent}:
        p.s(cpsStmts).addAssignment(derefField(rl, "bytes"), cIntValue(0))
        p.s(cpsStmts).addAssignment(derefField(rl, "more"), NimNil)
      else:
        p.s(cpsStmts).addAssignment(dotField(rl, "bytes"), cIntValue(0))
        p.s(cpsStmts).addAssignment(dotField(rl, "more"), NimNil)
    elif atyp.kind in {tyVar, tyLent}:
      p.s(cpsStmts).addAssignment(derefField(rl, "len"), cIntValue(0))
      p.s(cpsStmts).addAssignment(derefField(rl, "p"), NimNil)
    else:
      p.s(cpsStmts).addAssignment(dotField(rl, "len"), cIntValue(0))
      p.s(cpsStmts).addAssignment(dotField(rl, "p"), NimNil)
  elif not isComplexValueType(typ):
    if containsGcRef:
      var nilLoc: TLoc = initLoc(locTemp, loc.lode, OnStack)
      nilLoc.snippet = NimNil
      genRefAssign(p, loc, nilLoc)
    else:
      p.s(cpsStmts).addAssignment(rdLoc(loc), cIntValue(0))
  else:
    if loc.storage != OnStack and containsGcRef:
      specializeReset(p, loc)
      when false:
        linefmt(p, cpsStmts, "#genericReset((void*)$1, $2);$n",
                [addrLoc(p.config, loc), genTypeInfoV1(p.module, loc.t, loc.lode.info)])
      # XXX: generated reset procs should not touch the m_type
      # field, so disabling this should be safe:
      genObjectInit(p, cpsStmts, loc.t, loc, constructObj)
    else:
      # array passed as argument decayed into pointer, bug #7332
      # so we use getTypeDesc here rather than rdLoc(loc)
      let tyDesc = getTypeDesc(p.module, loc.t, descKindFromSymKind mapTypeChooser(loc))
      if p.module.compileToCpp and isOrHasImportedCppType(typ):
        if lfIndirect in loc.flags:
          #C++ cant be just zeroed. We need to call the ctors
          var tmp = getTemp(p, loc.t)
          let ral = addrLoc(p.config, loc)
          let ratmp = addrLoc(p.config, tmp)
          p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimCopyMem"),
            cCast(CPointer, ral),
            cCast(CConstPointer, ratmp),
            cSizeof(tyDesc))
      else:
        let ral = addrLoc(p.config, loc)
        p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimZeroMem"),
          cCast(CPointer, ral),
          cSizeof(tyDesc))

      # XXX: We can be extra clever here and call memset only
      # on the bytes following the m_type field?
      genObjectInit(p, cpsStmts, loc.t, loc, constructObj)

proc constructLoc(p: BProc, loc: var TLoc, isTemp = false) =
  let typ = loc.t
  if optSeqDestructors in p.config.globalOptions and skipTypes(typ, abstractInst + {tyStatic}).kind in {tyString, tySequence}:
    let rl = rdLoc(loc)
    if skipTypes(typ, abstractInst + {tyStatic}).kind == tyString and p.config.usesSso():
      # SmallString zero state: bytes=0 (slen=0 in low byte, all inline chars zeroed)
      p.s(cpsStmts).addFieldAssignment(rl, "bytes", cIntValue(0))
      p.s(cpsStmts).addFieldAssignment(rl, "more", NimNil)
    else:
      p.s(cpsStmts).addFieldAssignment(rl, "len", cIntValue(0))
      p.s(cpsStmts).addFieldAssignment(rl, "p", NimNil)
  elif not isComplexValueType(typ):
    if containsGarbageCollectedRef(loc.t):
      var nilLoc: TLoc = initLoc(locTemp, loc.lode, OnStack)
      nilLoc.snippet = NimNil
      genRefAssign(p, loc, nilLoc)
    else:
      let rl = rdLoc(loc)
      let rt = getTypeDesc(p.module, typ, descKindFromSymKind mapTypeChooser(loc))
      p.s(cpsStmts).addAssignment(rl, cCast(rt, cIntValue(0)))
  else:
    if (not isTemp or containsGarbageCollectedRef(loc.t)) and not hasNoInit(loc.t):
      # don't use nimZeroMem for temporary values for performance if we can
      # avoid it:
      if not isOrHasImportedCppType(typ):
        let ral = addrLoc(p.config, loc)
        let rt = getTypeDesc(p.module, typ, descKindFromSymKind mapTypeChooser(loc))
        p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimZeroMem"),
          cCast(CPointer, ral),
          cSizeof(rt))
    genObjectInit(p, cpsStmts, loc.t, loc, constructObj)

proc initLocalVar(p: BProc, v: PSym, immediateAsgn: bool) =
  if sfNoInit notin v.flags:
    # we know it is a local variable and thus on the stack!
    # If ``not immediateAsgn`` it is not initialized in a binding like
    # ``var v = X`` and thus we need to init it.
    # If ``v`` contains a GC-ref we may pass it to ``unsureAsgnRef`` somehow
    # which requires initialization. However this can really only happen if
    # ``var v = X()`` gets transformed into ``X(&v)``.
    # Nowadays the logic in ccgcalls deals with this case however.
    if not immediateAsgn:
      backendEnsureMutable v
      constructLoc(p, v.locImpl)

proc getTemp(p: BProc, t: PType, needsInit=false): TLoc =
  inc(p.labels)
  result = TLoc(snippet: "T" & rope(p.labels) & "_", k: locTemp, lode: lodeTyp t,
                storage: OnStack, flags: {})
  if p.module.compileToCpp and isOrHasImportedCppType(t):
    var didGenTemp = false
    linefmt(p, cpsLocals, "$1 $2$3;$n", [getTypeDesc(p.module, t, dkVar), result.snippet,
      genCppInitializer(p.module, p, t, didGenTemp)])
  else:
    p.s(cpsLocals).addVar(kind = Local,
      name = result.snippet,
      typ = getTypeDesc(p.module, t, dkVar))
  constructLoc(p, result, not needsInit)
  when false:
    # XXX Introduce a compiler switch in order to detect these easily.
    if getSize(p.config, t) > 1024 * 1024:
      if p.prc != nil:
        echo "ENORMOUS TEMPORARY! ", p.config $ p.prc.info
      else:
        echo "ENORMOUS TEMPORARY! ", p.config $ p.lastLineInfo
      writeStackTrace()

proc getTempCpp(p: BProc, t: PType, value: Rope): TLoc =
  inc(p.labels)
  result = TLoc(snippet: "T" & rope(p.labels) & "_", k: locTemp, lode: lodeTyp t,
                storage: OnStack, flags: {})
  p.s(cpsStmts).addVar(kind = Local,
    name = result.snippet,
    typ = "auto",
    initializer = value)

proc getIntTemp(p: BProc): TLoc =
  inc(p.labels)
  result = TLoc(snippet: "T" & rope(p.labels) & "_", k: locTemp,
                storage: OnStack, lode: lodeTyp getSysType(p.module.g.graph, unknownLineInfo, tyInt),
                flags: {})
  p.s(cpsLocals).addVar(kind = Local, name = result.snippet, typ = NimInt)

proc localVarDecl(res: var Builder, p: BProc; n: PNode,
                  initializer: Snippet = "",
                  initializerKind: VarInitializerKind = Assignment) =
  let s = n.sym
  if s.loc.k == locNone:
    fillLocalName(p, s)
    backendEnsureMutable s
    fillLoc(s.locImpl, locLocalVar, n, OnStack)
    if s.kind == skLet: incl(s, lfNoDeepCopy)
  else:
    # Already named by an EARLIER emission of this same routine — an inline proc
    # regenerated per user, or (under a batched `cg`) a definition emitted into
    # two of this process's TUs. `fillLocalName` caches the C name on the PSym
    # but takes the uniquifying counter from the BProc, and this BProc is a new
    # one whose `sigConflicts` never saw that name. Claim it, or the next local
    # of the same base name minted HERE starts from `_1` again and redeclares
    # it: gcc "redeclaration of 'i_1' with no linkage", 64 of Atlas's 204 `.c`
    # at batch size 4.
    p.sigConflicts.inc(s.name.s.mangle)

  genCLineDir(res, p, n.info, p.config)

  res.addVar(p.module, s,
    name = s.loc.snippet,
    typ = getTypeDesc(p.module, s.typ, dkVar),
    initializer = initializer,
    initializerKind = initializerKind)

proc assignLocalVar(p: BProc; n: PNode) =
  #assert(s.loc.k == locNone) # not yet assigned
  # this need not be fulfilled for inline procs; they are regenerated
  # for each module that uses them!
  var initializer: Snippet = ""
  var initializerKind: VarInitializerKind = Assignment
  if p.module.compileToCpp and isOrHasImportedCppType(n.typ):
    var didGenTemp = false
    initializer = genCppInitializer(p.module, p, n.typ, didGenTemp)
    initializerKind = CppConstructor
  localVarDecl(p.s(cpsLocals), p, n, initializer, initializerKind)
  if optLineDir in p.config.options:
    p.s(cpsLocals).add("\n")

include ccgthreadvars

proc varInDynamicLib(m: BModule, sym: PSym)

proc treatGlobalDifferentlyForHCR(m: BModule, s: PSym): bool =
  return m.hcrOn and {sfThread, sfGlobal} * s.flags == {sfGlobal} and
      ({lfNoDecl, lfHeader} * s.loc.flags == {})
      # and s.owner.kind == skModule # owner isn't always a module (global pragma on local var)
      # and s.loc.k == locGlobalVar  # loc isn't always initialized when this proc is used

proc genGlobalVarDecl(res: var Builder, p: BProc; n: PNode; td: Snippet;
                      initializer: Snippet = "",
                      initializerKind: VarInitializerKind = Assignment,
                      allowConst = true) =
  let s = n.sym
  let vis =
    if p.hcrOn: StaticProc
    elif sfImportc in s.flags: Extern
    elif lfExportLib in s.loc.flags: ExportLibVar
    else: Private
  var typ = td
  if allowConst and s.kind == skLet and initializer.len != 0:
    typ = constType(typ)
  if p.hcrOn:
    typ = ptrType(typ)
  if p.config.cmd == cmdNifC and vis == Private and sfImportc notin s.flags:
    # A `{.global.}` var (e.g. chronos's per-call-site `var loc {.global.} =
    # SrcLoc(...)`, or a gensym'd `var dummy`/`var topic` with no initializer)
    # declared inside a routine is emitted by every module that emit-everywhere's
    # its enclosing routine; its content-addressed name then collides at link.
    # Declare it `extern` + wrap the definition as a droppable `'d'` unit so the
    # merge stage keeps exactly one (like consts / TNimType / the NimDT
    # discriminator tables / the threadvar path). This covers no-initializer
    # globals too — they collide just the same. A module-level global has a
    # single claimant → its sole emitter is the owner merge keeps.
    let cname = stripCnifMarks(s.loc.snippet)
    res.addDeclWithVisibility(Extern):
      res.addVar(kind = Local, name = s.loc.snippet, typ = typ)
    res.add(cnifDefDirective(cname, "d", icNifName(p.module, s)))
    res.addVar(p.module, s,
      name = s.loc.snippet, typ = typ, visibility = vis,
      initializer = initializer, initializerKind = initializerKind)
    res.add(cnifEndDefs())
  else:
    res.addVar(p.module, s,
      name = s.loc.snippet,
      typ = typ,
      visibility = vis,
      initializer = initializer,
      initializerKind = initializerKind)

proc assignGlobalVar(p: BProc; n: PNode; value: Rope) =
  let s = n.sym
  if s.loc.k == locNone:
    fillBackendName(p.module, s)
    backendEnsureMutable s
    fillLoc(s.locImpl, locGlobalVar, n, OnHeap)
    if treatGlobalDifferentlyForHCR(p.module, s): incl(s, lfIndirect)

  if lfDynamicLib in s.loc.flags:
    var q = findPendingModule(p.module, s)
    if q != nil and not containsOrIncl(q.declaredThings, s.id):
      varInDynamicLib(q, s)
    else:
      backendEnsureMutable s
      s.locImpl.snippet = mangleDynLibProc(s)
    if value != "":
      internalError(p.config, n.info, ".dynlib variables cannot have a value")
    return
  useHeader(p.module, s)
  if lfNoDecl in s.loc.flags: return
  if not containsOrIncl(p.module.declaredThings, s.id):
    if p.config.cmd == cmdNifC and sfImportc notin s.flags:
      p.module.icDataDefs.add (stripCnifMarks(s.loc.snippet),
                               icNifName(p.module, s))
    if sfThread in s.flags:
      declareThreadVar(p.module, s, sfImportc in s.flags)
      if value != "":
        internalError(p.config, n.info, ".threadvar variables cannot have a value")
    else:
      let td = getTypeDesc(p.module, s.loc.t, dkVar)
      var initializer: Snippet = ""
      if s.constraint.isNil:
        if value != "":
          if p.module.compileToCpp and value.startsWith "{{}":
            # TODO: taking this branch, re"\{\{\}(,\s\{\})*\}" might be emitted, resulting in
            # either warnings (GCC 12.2+) or errors (Clang 15, MSVC 19.3+) of C++11+ compilers **when
            # explicit constructors are around** due to overload resolution rules in place [^0][^1][^2]
            # *Workaround* here: have C++'s static initialization mechanism do the default init work,
            # for us lacking a deeper knowledge of an imported object's constructors' ex-/implicitness
            # (so far) *and yet* trying to achieve default initialization.
            # Still, generating {}s in genConstObjConstr() just to omit them here is faaaar from ideal;
            # need to figure out a better way, possibly by keeping around more data about the
            # imported objects' contructors?
            #
            # [^0]: https://en.cppreference.com/w/cpp/language/aggregate_initialization
            # [^1]: https://cplusplus.github.io/CWG/issues/1518.html
            # [^2]: https://eel.is/c++draft/over.match.ctor
            discard
          else:
            initializer = value
        else:
          discard
      else:
        initializer = value
      genGlobalVarDecl(p.module.s[cfsVars], p, n, td, initializer = initializer)
  if p.withinLoop > 0 and value == "" and
      s.loc.t.skipTypes(abstractInst).kind notin {tyVar, tyLent}:
    # fixes tests/run/tzeroarray:
    # Don't reset borrowed references (var/lent): the pointer itself is still
    # uninitialized here, so resetLoc would dereference garbage. Such variables
    # (e.g. the loop var of `mitems`) are always assigned before use anyway.
    backendEnsureMutable s
    resetLoc(p, s.locImpl)

proc callGlobalVarCppCtor(p: BProc; v: PSym; vn: PNode; value: PNode; didGenTemp: var bool) =
  let s = vn.sym
  fillBackendName(p.module, s)
  backendEnsureMutable s
  fillLoc(s.locImpl, locGlobalVar, vn, OnHeap)
  let td = getTypeDesc(p.module, vn.sym.typ, dkVar)
  var val = genCppParamsForCtor(p, value, didGenTemp)
  if didGenTemp:  return # generated in the caller
  if val.len != 0:
    val = "(" & val & ")"
  genGlobalVarDecl(p.module.s[cfsVars], p, vn, td,
    initializer = val,
    initializerKind = CppConstructor,
    allowConst = false)

proc assignParam(p: BProc, s: PSym, retType: PType) =
  assert(s.loc.snippet != "")
  scopeMangledParam(p, s)

proc fillProcLoc(m: BModule; n: PNode) =
  let sym = n.sym
  if sym.loc.k == locNone:
    fillBackendName(m, sym)
    backendEnsureMutable sym
    fillLoc(sym.locImpl, locProc, n, OnStack)

proc getLabel(p: BProc): TLabel =
  inc(p.labels)
  result = "LA" & rope(p.labels) & "_"

proc fixLabel(p: BProc, labl: TLabel) =
  p.s(cpsStmts).addLabel(labl)

proc genVarPrototype(m: BModule, n: PNode)
proc requestConstImpl(p: BProc, sym: PSym)
proc genStmts(p: BProc, t: PNode)
proc expr(p: BProc, n: PNode, d: var TLoc)

proc putLocIntoDest(p: BProc, d: var TLoc, s: TLoc)
proc genLiteral(p: BProc; n: PNode; result: var Builder)
proc genOtherArg(p: BProc; ri: PNode; i: int; typ: PType; result: var Builder; argBuilder: var CallBuilder)
proc raiseExit(p: BProc)
proc raiseExitCleanup(p: BProc, destroy: string)

proc initLocExpr(p: BProc; e: PNode, flags: TLocFlags = {}): TLoc =
  result = initLoc(locNone, e, OnUnknown, flags)
  expr(p, e, result)

proc initLocExprSingleUse(p: BProc; e: PNode): TLoc =
  result = initLoc(locNone, e, OnUnknown)
  if e.kind in nkCallKinds and (e.firstSon.kind != nkSym or e.firstSon.sym.magic == mNone):
    # We cannot check for tfNoSideEffect here because of mutable parameters.
    discard "bug #8202; enforce evaluation order for nested calls for C++ too"
    # We may need to consider that 'f(g())' cannot be rewritten to 'tmp = g(); f(tmp)'
    # if 'tmp' lacks a move/assignment operator.
    if e.firstSon.kind == nkSym and sfCompileToCpp in e.firstSon.sym.flags:
      result.flags.incl lfSingleUse
  else:
    result.flags.incl lfSingleUse
  expr(p, e, result)

when defined(icCanRaiseLog):
  import std / syncio

  proc logCanRaise(s: PSym; verdict: bool) =
    ## One line per verdict, keyed by name + disamb + OWNING MODULE, and carrying
    ## the magic that usually decides the answer.
    ##
    ## The module is not decoration: `disamb` is a per-module counter, so `len.0`
    ## names a different routine in every module that has one, and a key without
    ## the module reports a collision as a disagreement. NOT the itemId — that is
    ## a per-build counter and would make every line differ for no reason.
    let m = getModule(s)
    stderr.writeLine "CANRAISE " & s.name.s & "." & $s.disamb & "." &
      (if m == nil: "?" else: m.name.s) & "|" & $verdict & "|" & $s.magic &
      "|b" & $canRaiseBranch

include ccgcalls, "ccgstmts.nim"

proc initFrame(p: BProc, procname, filename: Rope): Rope =
  # XXX cbuilder
  const frameDefines = """
$1define nimfr_(proc, file) \
  TFrame FR_; \
  FR_.procname = proc; FR_.filename = file; FR_.line = 0; FR_.len = 0; #nimFrame(&FR_);

$1define nimln_(n) \
  FR_.line = n;

$1define nimlf_(n, file) \
  FR_.line = n; FR_.filename = file;

"""
  if p.module.s[cfsFrameDefines].buf.len == 0:
    appcg(p.module, p.module.s[cfsFrameDefines], frameDefines, ["#"])

  cgsym(p.module, "nimFrame")
  result = ropecg(p.module, "\tnimfr_($1, $2);$n", [procname, filename])

proc initFrameNoDebug(p: BProc; frame, procname, filename: Snippet; line: int): Snippet =
  cgsym(p.module, "nimFrame")
  p.blocks[0].sections[cpsLocals].addVar(name = frame, typ = "TFrame")
  var res = newBuilder("")
  res.add('\t')
  res.addFieldAssignment(frame, "procname", procname)
  res.add('\t')
  res.addFieldAssignment(frame, "filename", filename)
  res.add('\t')
  res.addFieldAssignment(frame, "line", cIntValue(line))
  res.add('\t')
  res.addFieldAssignment(frame, "len", cIntValue(-1))
  res.add('\t')
  res.addCallStmt("nimFrame", cAddr(frame))
  result = extract(res)

proc deinitFrameNoDebug(p: BProc; frame: Snippet): Snippet =
  var res = newBuilder("")
  res.add('\t')
  res.addCallStmt(cgsymValue(p.module, "popFrameOfAddr"), cAddr(frame))
  result = extract(res)

proc deinitFrame(p: BProc): Snippet =
  var res = newBuilder("")
  res.add('\t')
  res.addCallStmt(cgsymValue(p.module, "popFrame"))
  result = extract(res)

include ccgexprs

# ----------------------------- dynamic library handling -----------------
# We don't finalize dynamic libs as the OS does this for us.

proc isGetProcAddr(lib: PLib): bool =
  let n = lib.path
  result = n.kind in nkCallKinds and n.typ != nil and
    n.typ.kind in {tyPointer, tyProc}

proc loadDynamicLib(m: BModule, lib: PLib) =
  assert(lib != nil)
  if not lib.generated:
    lib.generated = true
    var tmp = getTempName(m)
    assert(lib.name == "")
    lib.name = tmp # BUGFIX: cgsym has awful side-effects
    let loadFn = cgsymValue(m, "nimLoadLibrary")
    let loadErrorFn = cgsymValue(m, "nimLoadLibraryError")
    m.s[cfsVars].addVar(Global, name = tmp, typ = CPointer)
    if lib.path.kind in {nkStrLit..nkTripleStrLit}:
      var s: TStringSeq = @[]
      libCandidates(lib.path.strVal, s)
      rawMessage(m.config, hintDependency, lib.path.strVal)
      let last = high(s)
      for i in 0..last:
        inc(m.labels)
        template doLoad(j: int) =
          let n = newStrNode(nkStrLit, s[j])
          n.info = lib.path.info
          m.s[cfsDynLibInit].addAssignmentWithValue(tmp):
            var call: CallBuilder
            m.s[cfsDynLibInit].addCall(call, loadFn):
              m.s[cfsDynLibInit].addArgument(call):
                genStringLiteral(m, n, m.s[cfsDynLibInit])
        if i == 0:
          doLoad(i)
        m.s[cfsDynLibInit].addSingleIfStmt(cOp(Not, tmp)):
          if i == last:
            m.s[cfsDynLibInit].addStmt():
              var call: CallBuilder
              m.s[cfsDynLibInit].addCall(call, loadErrorFn):
                m.s[cfsDynLibInit].addArgument(call):
                  genStringLiteral(m, lib.path, m.s[cfsDynLibInit])
          else:
            doLoad(i + 1)

    else:
      var p = newProc(nil, m)
      p.options.excl optStackTrace
      p.flags.incl nimErrorFlagDisabled
      var dest: TLoc = initLoc(locTemp, lib.path, OnStack)
      dest.snippet = getTempName(m)
      m.s[cfsDynLibInit].addVar(name = rdLoc(dest), typ = getTypeDesc(m, lib.path.typ, dkVar))
      expr(p, lib.path, dest)

      m.s[cfsVars].add(extract(p.s(cpsLocals)))
      m.s[cfsDynLibInit].add(extract(p.s(cpsInit)))
      m.s[cfsDynLibInit].add(extract(p.s(cpsStmts)))
      let rd = rdLoc(dest)
      m.s[cfsDynLibInit].addAssignment(tmp,
        cCall(loadFn, rd))
      m.s[cfsDynLibInit].addSingleIfStmt(cOp(Not, tmp)):
        m.s[cfsDynLibInit].addCallStmt(loadErrorFn, rd)

  if lib.name == "": internalError(m.config, "loadDynamicLib")

proc mangleDynLibProc(sym: PSym): Rope =
  # we have to build this as a single rope in order not to trip the
  # optimization in genInfixCall, see test tests/cpp/t8241.nim
  if sfCompilerProc in sym.flags:
    # NOTE: sym.loc.snippet is the external name!
    result = rope(sym.name.s)
  else:
    result = rope(strutils.`%`("Dl_$1_", $sym.id))

proc symInDynamicLib(m: BModule, sym: PSym) =
  var lib = sym.annex
  let isCall = isGetProcAddr(lib)
  var extname = sym.loc.snippet
  if not isCall: loadDynamicLib(m, lib)
  var tmp = mangleDynLibProc(sym)
  backendEnsureMutable sym
  sym.locImpl.snippet = tmp             # from now on we only need the internal name
  sym.typ.sym = nil           # generate a new name
  inc(m.labels, 2)
  if isCall:
    let n = lib.path
    var a: TLoc = initLocExpr(m.initProc, n.firstSon)
    let callee = rdLoc(a)
    var params: seq[Snippet] = @[]
    var remaining = n.len - 2   # children 1 ..< len-1
    for it in sonsFrom(n, 1):
      if remaining <= 0: break
      dec remaining
      a = initLocExpr(m.initProc, it)
      params.add(rdLoc(a))
    params.add(makeCString($extname))
    template load(builder: var Builder) =
      builder.add('\t')
      builder.addAssignment(tmp,
        cCast(getTypeDesc(m, sym.typ, dkVar),
          cCall(callee, params)))
    var last = lastSon(n)
    if last.kind == nkHiddenStdConv: last = last.secondSon
    internalAssert(m.config, last.kind == nkStrLit)
    let idx = last.strVal
    if idx.len == 0:
      load(m.initProc.s(cpsStmts))
    elif idx.len == 1 and idx[0] in {'0'..'9'}:
      load(m.extensionLoaders[idx[0]])
    else:
      internalError(m.config, sym.info, "wrong index: " & idx)
  else:
    # cgsym has side effects, do it first:
    let fn = cgsymValue(m, "nimGetProcAddr")
    m.s[cfsDynLibInit].add('\t')
    m.s[cfsDynLibInit].addAssignment(tmp,
      cCast(getTypeDesc(m, sym.typ, dkVar),
        cCall(fn,
          lib.name,
          makeCString($extname))))
  m.s[cfsVars].addVar(name = sym.loc.snippet, typ = getTypeDesc(m, sym.loc.t, dkVar))

proc varInDynamicLib(m: BModule, sym: PSym) =
  var lib = sym.annex
  var extname = sym.loc.snippet
  loadDynamicLib(m, lib)
  incl(sym, lfIndirect)
  var tmp = mangleDynLibProc(sym)
  backendEnsureMutable sym
  sym.locImpl.snippet = tmp             # from now on we only need the internal name
  inc(m.labels, 2)
  let t = ptrType(getTypeDesc(m, sym.typ, dkVar))
  # cgsym has side effects, do it first:
  let fn = cgsymValue(m, "nimGetProcAddr")
  m.s[cfsDynLibInit].addAssignment(tmp,
    cCast(t,
      cCall(fn,
        lib.name,
        makeCString($extname))))
  m.s[cfsVars].addVar(name = sym.loc.snippet, typ = t)

proc symInDynamicLibPartial(m: BModule, sym: PSym) =
  backendEnsureMutable sym
  sym.locImpl.snippet = mangleDynLibProc(sym)
  sym.typ.sym = nil           # generate a new name

proc cgsymImpl(m: BModule; sym: PSym) {.inline.} =
  case sym.kind
  of skProc, skFunc, skMethod, skConverter, skIterator: genProc(m, sym)
  of skVar, skResult, skLet: genVarPrototype(m, newSymNode sym)
  of skType: discard getTypeDesc(m, sym.typ)
  else: internalError(m.config, "cgsym: " & $sym.kind)

proc cgsym(m: BModule, name: string) =
  let sym = magicsys.getCompilerProc(m.g.graph, name)
  if sym != nil:
    cgsymImpl m, sym
  else:
    rawMessage(m.config, errGenerated, "system module needs: " & name)

proc cgsymValue(m: BModule, name: string): Rope =
  let sym = magicsys.getCompilerProc(m.g.graph, name)
  if sym != nil:
    cgsymImpl m, sym
  else:
    rawMessage(m.config, errGenerated, "system module needs: " & name)
  result = sym.loc.snippet
  if m.hcrOn and sym != nil and sym.kind in {skProc..skIterator}:
    result.addActualSuffixForHCR(m.module, sym)

proc generateHeaders(m: BModule) =
  var nimbase = m.config.nimbasePattern
  if nimbase == "": nimbase = "nimbase.h"
  m.s[cfsHeaders].addInclude('"' & nimbase & '"')

  for it in m.headerFiles:
    if it[0] == '#':
      m.s[cfsHeaders].add(rope(it.replace('`', '"') & "\L"))
    elif it[0] notin {'"', '<'}:
      m.s[cfsHeaders].addInclude('"' & $it & '"')
    else:
      m.s[cfsHeaders].addInclude($it)
  m.s[cfsHeaders].add("""#undef LANGUAGE_C
#undef MIPSEB
#undef MIPSEL
#undef PPC
#undef R3000
#undef R4000
#undef i386
#undef linux
#undef mips
#undef near
#undef far
#undef powerpc
#undef unix
""")

proc openNamespaceNim(namespace: string; result: var Builder) =
  result.add("namespace ")
  result.add(namespace)
  result.add(" {\L")

proc closeNamespaceNim(result: var Builder) =
  result.add("}\L")

proc closureSetup(p: BProc, prc: PSym) =
  if tfCapturesEnv notin prc.typ.flags: return
  # The `paramsPos` child of `prc.ast` has the type we're after — BUT a closure loaded
  # from a `.t.bif` (a lambda-lifted nested proc / generic instance the `lower`
  # stage transformed) can arrive with an EMPTY AST param node: the lifted hidden
  # `:env` param lives in `typ.n`, the authoritative signature (`genProc` already
  # reads `typ.n`, not the AST). The two param nodes diverge across the NIF
  # boundary; fall back to `typ.n` so the env param resolves instead of indexing
  # an empty container.
  var params = son(prc.ast, paramsPos)
  if params.safeLen == 0 and prc.typ.n != nil and prc.typ.n.kind == nkFormalParams:
    params = prc.typ.n
  var ls = lastSon(params)
  if ls.kind != nkSym:
    internalError(p.config, prc.info, "closure generation failed")
  var env = ls.sym
  #echo "created environment: ", env.id, " for ", prc.name.s
  assignLocalVar(p, ls)
  # generate cast assignment:
  if p.config.selectedGC == gcGo:
    let renv = addrLoc(p.config, env.loc)
    let rt = getTypeDesc(p.module, env.typ)
    p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "unsureAsgnRef"),
      cCast(ptrType(CPointer), renv),
      cCast(rt, "ClE_0"))
  else:
    let renv = rdLoc(env.loc)
    let rt = getTypeDesc(p.module, env.typ)
    p.s(cpsStmts).addAssignment(renv, cCast(rt, "ClE_0"))

const harmless = {nkConstSection, nkTypeSection, nkEmpty, nkCommentStmt, nkTemplateDef,
                  nkMacroDef, nkMixinStmt, nkBindStmt, nkFormalParams} +
                  declarativeDefs

proc containsResult(n: PNode): bool =
  result = false
  case n.kind
  of succ(nkEmpty)..pred(nkSym), succ(nkSym)..nkNilLit, harmless:
    discard
  of nkReturnStmt:
    for ni in sons(n):
      if containsResult(ni): return true
    result = n.hasSons and n.firstSon.kind == nkEmpty
  of nkSym:
    if n.sym.kind == skResult:
      result = true
  else:
    for ni in sons(n):
      if containsResult(ni): return true

proc easyResultAsgn(n: PNode): PNode =
  result = nil
  case n.kind
  of nkStmtList, nkStmtListExpr:
    var i = 0
    while i < n.len and n[i].kind in harmless: inc i
    if i < n.len: result = easyResultAsgn(n[i])
  of nkAsgn, nkFastAsgn, nkSinkAsgn:
    if n.firstSon.kind == nkSym and n.firstSon.sym.kind == skResult and not containsResult(n.secondSon):
      incl n.flags, nfPreventCg
      return n.secondSon
  of nkReturnStmt:
    if n.hasSons:
      result = easyResultAsgn(n.firstSon)
      if result != nil: incl n.flags, nfPreventCg
  else: discard

type
  InitResultEnum = enum Unknown, InitSkippable, InitRequired

proc allPathsAsgnResult(p: BProc; n: PNode): InitResultEnum =
  # Exceptions coming from calls don't have not be considered here:
  #
  # proc bar(): string = raise newException(...)
  #
  # proc foo(): string =
  #   # optimized out: 'reset(result)'
  #   result = bar()
  #
  # try:
  #   a = foo()
  # except:
  #   echo "a was not written to"
  #
  template allPathsInBranch(it) =
    let a = allPathsAsgnResult(p, it)
    case a
    of InitRequired: return InitRequired
    of InitSkippable: discard
    of Unknown:
      # sticky, but can be overwritten by InitRequired:
      result = Unknown

  result = Unknown
  case n.kind
  of nkStmtList, nkStmtListExpr:
    for it in sons(n):
      result = allPathsAsgnResult(p, it)
      if result != Unknown: return result
  of nkAsgn, nkFastAsgn, nkSinkAsgn:
    if n.firstSon.kind == nkSym and n.firstSon.sym.kind == skResult:
      if not containsResult(n.secondSon):
        if allPathsAsgnResult(p, n.secondSon) == InitRequired:
          result = InitRequired
        else:
          result = InitSkippable
      else: result = InitRequired
    elif containsResult(n):
      result = InitRequired
    else:
      result = allPathsAsgnResult(p, n.secondSon)
  of nkReturnStmt:
    if n.hasSons:
      if n.firstSon.kind == nkEmpty and result != InitSkippable:
        # This is a bare `return` statement, if `result` was not initialized
        # anywhere else (or if we're not sure about this) let's require it to be
        # initialized. This avoids cases like #9286 where this heuristic lead to
        # wrong code being generated.
        result = InitRequired
      else: result = allPathsAsgnResult(p, n.firstSon)
  of nkIfStmt, nkIfExpr:
    var exhaustive = false
    result = InitSkippable
    for it in sons(n):
      # Every condition must not use 'result':
      if it.len == 2 and containsResult(it.firstSon):
        return InitRequired
      if it.len == 1: exhaustive = true
      allPathsInBranch(it.lastSon)
    # if the 'if' statement is not exhaustive and yet it touched 'result'
    # in some way, say Unknown.
    if not exhaustive: result = Unknown
  of nkCaseStmt:
    if containsResult(n.firstSon): return InitRequired
    result = InitSkippable
    var exhaustive = skipTypes(n.firstSon.typ,
        abstractVarRange-{tyTypeDesc}).kind notin {tyFloat..tyFloat128, tyString, tyCstring}
    for it in sonsFrom(n, 1):
      allPathsInBranch(it.lastSon)
      if it.kind == nkElse: exhaustive = true
    if not exhaustive: result = Unknown
  of nkWhileStmt:
    # some dubious code can assign the result in the 'while'
    # condition and that would be fine. Everything else isn't:
    result = allPathsAsgnResult(p, n.firstSon)
    if result == Unknown:
      result = allPathsAsgnResult(p, n.secondSon)
      # we cannot assume that the 'while' loop is really executed at least once:
      if result == InitSkippable: result = Unknown
  of harmless:
    result = Unknown
  of nkGotoState, nkBreakState:
    # give up for now.
    result = InitRequired
  of nkSym:
    # some path reads from 'result' before it was written to!
    if n.sym.kind == skResult: result = InitRequired
  of nkTryStmt, nkHiddenTryStmt:
    # We need to watch out for the following problem:
    # try:
    #   result = stuffThatRaises()
    # except:
    #   discard "result was not set"
    #
    # So ... even if the assignment to 'result' is the very first
    # assignment this is not good enough! The only pattern we allow for
    # is 'finally: result = x'
    result = InitSkippable
    allPathsInBranch(n.firstSon)
    for it in sonsFrom(n, 1):
      if it.kind == nkFinally:
        result = allPathsAsgnResult(p, it.lastSon)
      else:
        allPathsInBranch(it.lastSon)
  of nkCallKinds:
    if canRaiseDisp(p, n.firstSon) or
        (n.firstSon.kind == nkSym and sfNoReturn in n.firstSon.sym.flags):
      # requires initializations when encountering unreachable code
      result = InitRequired
    elif n.firstSon.kind == nkSym and
        n.firstSon.sym.magic in {mUnaryMinusI..mAbsI, mAddI..mPred} and
          optOverflowCheck in p.config.options:
      # arithmetic operations may raise exceptions
      result = InitRequired
    else:
      for it in sons(n):
        allPathsInBranch(it)
  of nkRaiseStmt:
    result = InitRequired
  of nkChckRangeF, nkChckRange64, nkChckRange:
    # TODO: more checks might need to be covered like overflow, indexDefect etc.
    # bug #22852
    result = InitRequired
  else:
    for it in sons(n):
      allPathsInBranch(it)

proc getProcTypeCast(m: BModule, prc: PSym): Rope =
  result = getTypeDesc(m, prc.loc.t)
  if prc.typ.callConv == ccClosure:
    var rettype: Snippet = ""
    var desc = newBuilder("")
    var check = initIntSet()
    genProcParams(m, prc.typ, rettype, desc, check)
    let params = extract(desc)
    result = procPtrTypeUnnamed(rettype = rettype, params = params)

proc genProcBody(p: BProc; procBody: PNode) =
  genStmts(p, procBody) # modifies p.locals, p.init, etc.
  if {nimErrorFlagAccessed, nimErrorFlagDeclared, nimErrorFlagDisabled} * p.flags == {nimErrorFlagAccessed}:
    p.flags.incl nimErrorFlagDeclared
    p.blocks[0].sections[cpsLocals].addVar(kind = Local,
      name = "nimErr_", typ = ptrType(NimBool))
    p.blocks[0].sections[cpsInit].addAssignmentWithValue("nimErr_"):
      p.blocks[0].sections[cpsInit].addCall(cgsymValue(p.module, "nimErrorFlag"))

proc genProcLvl3*(m: BModule, prc: PSym) =
  if m.config.cmd == cmdNifC:
    fillBackendName(m, prc)
    if (prc.disamb and (InstanceDisambBit or HookDisambBit)) != 0'i32 and
        containsOrIncl(m.emittedContentDefs, stripCnifMarks(prc.loc.snippet)):
      # A different symbol already emitted a body under this content-addressed
      # C name in this TU (same generic instance / hook minted in two source
      # modules, both loaded here). Emitting a second body is a C redefinition;
      # a prototype was already produced for it, so just stop.
      return
    if sfDispatcher in prc.flags and sfMainModule notin m.module.flags:
      # A method dispatcher enumerates the whole program's method set: its
      # body is synthesized by `generateIfMethodDispatchers` only after all
      # modules have been generated, and its single definition is emitted
      # into the main TU by `finishModule` (main is finished last and never
      # reused, so the definition can never go stale inside a cached TU).
      # Any demand before that point yields a prototype.
      genProcPrototype(m, prc)
      return
    if prc.itemId.module != m.module.position and
        not isBackendMinted(prc.itemId) and
        (prc.typ == nil or prc.typ.callConv != ccInline) and
        sfDispatcher notin prc.flags:
      # this TU embeds a definition whose body lives in another module's
      # NIF: record the impl dependency (the artifact's cdeps head) so the
      # reuse gate re-checks that module's impl cookie. Inline bodies are
      # already part of the iface cookie; dispatcher bodies are synthesized
      # from the whole program and live in main, which never reuses.
      m.icImplMods.incl prc.itemId.module
  var p = newProc(prc, m)
  var header = newBuilder("")
  let isCppMember = m.config.backend == backendCpp and sfCppMember * prc.flags != {}
  var visibility: DeclVisibility = None
  if isCppMember:
    genMemberProcHeader(m, prc, header)
  else:
    genProcHeader(m, prc, header, visibility, asPtr = false, addAttributes = false)
  var returnStmt: Snippet = ""
  assert(prc.ast != nil)

  # A body LOADED from `.t.bif` was already FULLY lowered by the `lower` stage —
  # transformed AND destructor-injected (see nifbackend.generateLowerStage). The
  # `.t.bif` is the authoritative backend artifact; re-injecting here would lower
  # it twice (double `=destroy` calls) and, worse, re-lift the env hooks per cg
  # process (owned by nobody → undefined at link). So inject ONLY when the body
  # was re-derived in this process (`wasLoaded == false`). Capture before
  # `transformBody`, which returns the cached body (non-nil) when it was loaded.
  # ONLY under IC: in a normal `nim c` build `transformedBody` is the ordinary
  # transform cache (set whenever `transformBody` already ran for `prc`, e.g. a
  # CT-evaluated or earlier-referenced routine), NOT a `.t.bif` load — gating on
  # it there would WRONGLY skip destructor injection and miscompile (orc
  # decref-on-freed). The `.t.bif`-loaded-body concept exists only under cmdNifC.
  let wasLoaded = m.config.cmd == cmdNifC and prc.transformedBody != nil
  icProfStart(tTransform)
  var procBody = transformBody(m.g.graph, m.idgen, prc, {})
  if sfInjectDestructors in prc.flags and not wasLoaded:
    procBody = injectDestructorCalls(m.g.graph, m.idgen, prc, procBody)
  icProfStop(tTransform)

  let tmpInfo = prc.info
  discard freshLineInfo(p, prc.info)

  if sfPure notin prc.flags and prc.typ.returnType != nil:
    if resultPos >= prc.ast.len:
      internalError(m.config, prc.info, "proc has no result symbol")
    let resNode = son(prc.ast, resultPos)
    let res = resNode.sym # get result symbol
    if not isInvalidReturnType(m.config, prc.typ) and sfConstructor notin prc.flags:
      if sfNoInit in prc.flags: incl(res, sfNoInit)
      if sfNoInit in prc.flags and p.module.compileToCpp and (let val = easyResultAsgn(procBody); val != nil):
        var a: TLoc = initLocExprSingleUse(p, val)
        let ra = rdLoc(a)
        localVarDecl(p.s(cpsStmts), p, resNode, initializer = ra)
      else:
        # declare the result symbol:
        assignLocalVar(p, resNode)
        assert(res.loc.snippet != "")
        let paths = allPathsAsgnResult(p, procBody)
        if p.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc} and
            paths == InitSkippable:
          # In an ideal world the codegen could rely on injectdestructors doing its job properly
          # and then the analysis step would not be required.
          discard "result init optimized out"
        else:
          initLocalVar(p, res, immediateAsgn=false)
      var returnBuilder = newBuilder("\t")
      let rres = rdLoc(res.loc)
      returnBuilder.addReturn(rres)
      returnStmt = extract(returnBuilder)
    elif sfConstructor in prc.flags:
      resNode.sym.incl lfIndirect
      backendEnsureMutable resNode.sym
      fillLoc(resNode.sym.locImpl, locParam, resNode, "this", OnHeap)
      backendEnsureMutable prc
      prc.locImpl.snippet = getTypeDesc(m, resNode.sym.locImpl.t, dkVar)
    else:
      fillResult(p.config, resNode, prc.typ)
      assignParam(p, res, prc.typ.returnType)
      # We simplify 'unsureAsgn(result, nil); unsureAsgn(result, x)'
      # to 'unsureAsgn(result, x)'
      # Sketch why this is correct: If 'result' points to a stack location
      # the 'unsureAsgn' is a nop. If it points to a global variable the
      # global is either 'nil' or points to valid memory and so the RC operation
      # succeeds without touching not-initialized memory.
      if sfNoInit in prc.flags: discard
      elif allPathsAsgnResult(p, procBody) == InitSkippable: discard
      else:
        backendEnsureMutable res
        resetLoc(p, res.locImpl)
      if skipTypes(res.typ, abstractInst).kind == tyArray:
        #incl(res.loc.flags, lfIndirect)
        backendEnsureMutable res
        res.locImpl.storage = OnUnknown

  for paramNode in sonsFrom(prc.typ.n, 1):
    let param = paramNode.sym
    if param.typ.isCompileTimeOnly: continue
    if prc.typ.callConv == ccClosure and param.name.s == ":envP":
      # The hidden closure-env param is materialised by `closureSetup`, never a
      # normal C parameter (`genProcParams` omits it from the signature). In a
      # from-source build it lives only in the routine's AST params and never in
      # `typ.n`, so this loop never reaches it. Under IC `closureParams` leaks it
      # into `typ.n`; for a LOADED closure it is already present at header time
      # (`genProcParams` fills its loc), but for a RE-DERIVED closure
      # (`wasLoaded == false`) `transformBody` appends it only AFTER
      # `genProcHeader` ran, so its `loc.snippet` is still empty here. Skip it to
      # match the from-source invariant — `closureSetup` assigns its local below.
      continue
    assignParam(p, param, prc.typ.returnType)
  closureSetup(p, prc)
  icProfStart(tGenBody)
  genProcBody(p, procBody)
  icProfStop(tGenBody)

  # IC: spurious write, seems fine for now:
  prc.infoImpl = tmpInfo

  var generatedProc = newBuilder("")
  generatedProc.genCLineDir prc.info, m.config
  generatedProc.addDeclWithVisibility(visibility):
    if sfPure in prc.flags:
      generatedProc.add(extract(header))
      generatedProc.finishProcHeaderWithBody():
        generatedProc.add(extract(p.s(cpsLocals)))
        generatedProc.add(extract(p.s(cpsInit)))
        generatedProc.add(extract(p.s(cpsStmts)))
    else:
      if m.hcrOn and isReloadable(m, prc):
        m.s[cfsProcHeaders].addDeclWithVisibility(visibility):
          # Add forward declaration for "_actual"-suffixed functions defined in the same module (or inline).
          # This fixes the use of methods and also the case when 2 functions within the same module
          # call each other using directly the "_actual" versions (an optimization) - see issue #11608
          m.s[cfsProcHeaders].add(extract(header))
          m.s[cfsProcHeaders].finishProcHeaderAsProto()
      generatedProc.add(extract(header))
      generatedProc.finishProcHeaderWithBody():
        if optStackTrace in prc.options:
          generatedProc.add(extract(p.s(cpsLocals)))
          var procname = makeCString(prc.name.s)
          generatedProc.add(initFrame(p, procname, quotedFilename(p.config, prc.info)))
        else:
          generatedProc.add(extract(p.s(cpsLocals)))
        if optProfiler in prc.options:
          # invoke at proc entry for recursion:
          p.s(cpsInit).add('\t')
          p.s(cpsInit).addCallStmt(cgsymValue(m, "nimProfile"))
        if beforeRetNeeded in p.flags:
          # this pair of {} is required for C++ (C++ is weird with its
          # control flow integrity checks):
          generatedProc.addScope():
            generatedProc.add(extract(p.s(cpsInit)))
            generatedProc.add(extract(p.s(cpsStmts)))
          generatedProc.addLabel("BeforeRet_")
        else:
          generatedProc.add(extract(p.s(cpsInit)))
          generatedProc.add(extract(p.s(cpsStmts)))
        if optStackTrace in prc.options: generatedProc.add(deinitFrame(p))
        generatedProc.add(returnStmt)
  if m.config.cmd == cmdNifC:
    # definition directive for the cnif artifact: groups the proc's text
    # under its name and carries the root-relevant flags. The end directive
    # right after the text makes the definition self-delimiting, so raw
    # cfsProcs emitters (NimMain block, trav markers, ...) never end up
    # inside a definition's span.
    var defFlags = ""
    if sfExportc in prc.flags or sfConstructor in prc.flags: defFlags.add 'x'
    if sfCompilerProc in prc.flags: defFlags.add 'c'
    if prc.kind == skMethod or sfDispatcher in prc.flags: defFlags.add 'm'
    if (prc.typ == nil or prc.typ.callConv != ccInline) and
        sfDispatcher notin prc.flags:
      # A unique program-wide definition: external linkage, so exactly one
      # translation unit may embed its body and everyone else declares it.
      # Each module's `cg` process emits the body (emit-everywhere); this flag
      # tells the merge stage which definitions to assign a single owner and
      # prototype in the rest. The complement — inline procs and method
      # dispatchers — is emitted into every using TU (`static`/main-only) and
      # must never be deduplicated.
      defFlags.add 'u'
    if not hasCnifMarks(prc.loc.snippet):
      # The C name was not minted through `fillBackendName` (e.g. set by an
      # `extern`/`rtl` pragma at sem time), so its uses are invisible to the
      # artifact's liveness walk — conservatively keep the definition.
      defFlags.add 'x'
    # A C++ member's `loc.snippet` is a CALL PATTERN (`#->salute(@)`), not a
    # linker name — and every member of that name, in every class, mints the
    # same one. Ownership is assigned per name, so `Loo::salute` and `Foo::salute`
    # collided: the merge stage handed both to one artifact and the other TU's
    # definition was dropped (undefined vtable at link). Key member definitions by
    # their NIF name instead, which is unique by construction. Dots cannot occur
    # in a mangled C name, so the two namespaces stay disjoint.
    let defName =
      if sfCppMember * prc.flags != {}: icNifName(m, prc)
      else: stripCnifMarks(prc.loc.snippet)
    m.s[cfsProcs].add(cnifDefDirective(defName, defFlags, icNifName(m, prc)))
    m.s[cfsProcs].add(extract(generatedProc))
    m.s[cfsProcs].add(cnifEndDefs())
  else:
    m.s[cfsProcs].add(extract(generatedProc))
  if isReloadable(m, prc):
    m.s[cfsDynLibInit].add('\t')
    m.s[cfsDynLibInit].addAssignmentWithValue(prc.loc.snippet):
      m.s[cfsDynLibInit].addCast(getProcTypeCast(m, prc)):
        m.s[cfsDynLibInit].addCall("hcrRegisterProc",
          getModuleDllPath(m, prc),
          '"' & prc.loc.snippet & '"',
          cCast(CPointer, prc.loc.snippet & "_actual"))

proc requiresExternC(m: BModule; sym: PSym): bool {.inline.} =
  result = (sfCompileToCpp in m.module.flags and
           sfCompileToCpp notin sym.getModule().flags and
           m.config.backend != backendCpp) or (
           sym.flags * {sfInfixCall, sfCompilerProc, sfMangleCpp} == {} and
           sym.flags * {sfImportc, sfExportc} != {} and
           sym.magic == mNone and
           m.config.backend == backendCpp)

proc genProcPrototype(m: BModule, sym: PSym) =
  useHeader(m, sym)
  if lfNoDecl in sym.loc.flags: return
  if sfCppMember * sym.flags != {}:
    # A C++ member is declared INSIDE its class, never as a free prototype — but
    # this TU still needs its CALL-SITE name (`x->salute(@)`), and only
    # `genMemberProcHeader` derives that (from the pragma's declaration pattern).
    # Whole-program cgen got it for free: the module defining the member was code
    # generated in the same process, ahead of any caller. The per-module backend
    # emits that body in ANOTHER process, so the caller was left with the mangled
    # Nim name `fillBackendName` minted and C++ rejected
    # `loo->salute_u0__vireouyks1()` ("struct Loo has no member named ...").
    if m.compileToCpp:
      var scratch = newBuilder("")
      genMemberProcHeader(m, sym, scratch, false, true)
    return
  if lfDynamicLib in sym.loc.flags:
    # Does THIS TU emit the dynlib proc's definition? Under IC cg it does
    # whenever `findPendingModule` routes the symbol here — which it does unless
    # the owner is another member of this process's batch. Mirrored rather than
    # called, because `findPendingModule` creates a `BModule` on demand and a
    # prototype has no business doing that.
    let owner = getModule(sym)
    let emittedByABatchSibling =
      owner != nil and owner.kind == skModule and
      owner.position != m.module.position and
      m.g.icEmitted.contains(owner.position)
    if m.config.cmd == cmdNifC and m.config.icBackendStage == "cg" and
        not emittedByABatchSibling:
      # This TU emits the DEFINITION itself: `symInDynamicLib` follows this call
      # and the merge stage keeps one def per C name. Emitting the cross-module
      # `extern` proto here would register `sym.id` in `m.declaredThings` and
      # thereby make that `symInDynamicLib` skip, leaving the `Dl_*` symbol
      # declared-but-never-defined -> undefined at link.
      discard "definition emitted by symInDynamicLib"
    elif sym.itemId.module != m.module.position and
        not containsOrIncl(m.declaredThings, sym.id):
      let vis = if isReloadable(m, sym): StaticProc else: Extern
      let name = mangleDynLibProc(sym)
      let t = getTypeDesc(m, sym.loc.t)
      m.s[cfsVars].addDeclWithVisibility(vis):
        m.s[cfsVars].addVar(kind = Local,
          name = name,
          typ = t)
      if isReloadable(m, sym):
        m.s[cfsDynLibInit].add('\t')
        m.s[cfsDynLibInit].addAssignmentWithValue(name):
          m.s[cfsDynLibInit].addCast(t):
            m.s[cfsDynLibInit].addCall("hcrGetProc",
              getModuleDllPath(m, sym),
              '"' & name & '"')
  elif not containsOrIncl(m.declaredProtos, sym.id):
    if optCompress in m.config.globalOptions:
      m.queue.add(sym)
    let asPtr = isReloadable(m, sym)
    var header = newBuilder("")
    var visibility: DeclVisibility = None
    genProcHeader(m, sym, header, visibility, asPtr = asPtr, addAttributes = true)
    # A prototype is not a *use*: strip the cnif name marks so the artifact's
    # liveness walk does not see every forward-declared proc as referenced.
    var headerText = extract(header)
    if m.config.cmd == cmdNifC:
      headerText = stripCnifMarks(headerText)
    if asPtr:
      m.s[cfsProcHeaders].addDeclWithVisibility(visibility):
        # genProcHeader would give variable declaration, add it directly
        m.s[cfsProcHeaders].add(headerText)
    else:
      let extraVis =
        if sym.typ.callConv != ccInline and requiresExternC(m, sym):
          ExternC
        else:
          None
      m.s[cfsProcHeaders].addDeclWithVisibility(extraVis):
        m.s[cfsProcHeaders].addDeclWithVisibility(visibility):
          m.s[cfsProcHeaders].add(headerText)
          m.s[cfsProcHeaders].finishProcHeaderAsProto()

include inliner

proc genProcLvl2(m: BModule, prc: PSym) =
  if lfImportCompilerProc in prc.loc.flags:
    fillProcLoc(m, son(prc.ast, namePos))
    useHeader(m, prc)
    # dependency to a compilerproc:
    cgsym(m, prc.name.s)
    return
  if lfNoDecl in prc.loc.flags:
    fillProcLoc(m, son(prc.ast, namePos))
    genProcPrototype(m, prc)
  elif lfDynamicLib in prc.loc.flags:
    var q = findPendingModule(m, prc)
    fillProcLoc(q, son(prc.ast, namePos))
    genProcPrototype(m, prc)
    if q != nil and not containsOrIncl(q.declaredThings, prc.id):
      symInDynamicLib(q, prc)
      # register the procedure even though it is in a different dynamic library and will not be
      # reloadable (and has no _actual suffix) - other modules will need to be able to get it through
      # the hcr dynlib (also put it in the DynLibInit section - right after it gets loaded)
      if isReloadable(q, prc):
        q.s[cfsDynLibInit].add('\t')
        q.s[cfsDynLibInit].addAssignment(prc.loc.snippet,
          cCast(getTypeDesc(q, prc.loc.t),
            cCall("hcrRegisterProc",
              getModuleDllPath(m, q.module),
              '"' & prc.loc.snippet & '"',
              cCast(CPointer, prc.loc.snippet))))
    else:
      symInDynamicLibPartial(m, prc)
  elif prc.typ.callConv == ccInline:
    # We add inline procs to the calling module to enable C based inlining.
    # This also means that a check with ``q.declaredThings`` is wrong, we need
    # a check for ``m.declaredThings``.
    if not containsOrIncl(m.declaredThings, prc.id):
      #if prc.loc.k == locNone:
      # mangle the inline proc based on the module where it is defined -
      # not on the first module that uses it
      if m.module.itemId.module != prc.itemId.module and optCompress in m.config.globalOptions:
        let prcCopy = prc # copyInlineProc(prc, m.idgen)
        fillProcLoc(m, son(prcCopy.ast, namePos))
        genProcPrototype(m, prcCopy)
        genProcLvl3(m, prcCopy)
      else:
        let m2 = if m.config.symbolFiles != disabledSf: m
                else: findPendingModule(m, prc)
        fillProcLoc(m2, son(prc.ast, namePos))
        #elif {sfExportc, sfImportc} * prc.flags == {}:
        #  # reset name to restore consistency in case of hashing collisions:
        #  #echo "resetting ", prc.id, " by ", m.module.name.s
        #  #prc.loc.snippet = nil
        #  #prc.loc.snippet = mangleName(m, prc)
        genProcPrototype(m, prc)
        genProcLvl3(m, prc)
  elif sfImportc notin prc.flags:
    var q = findPendingModule(m, prc)
    fillProcLoc(q, son(prc.ast, namePos))
    # generate a getProc call to initialize the pointer for this
    # externally-to-the-current-module defined proc, also important
    # to do the declaredProtos check before the call to genProcPrototype
    if isReloadable(m, prc) and prc.id notin m.declaredProtos and
      q != nil and not sameModules(q.module, m.module):
      m.s[cfsDynLibInit].add('\t')
      m.s[cfsDynLibInit].addAssignment(prc.loc.snippet,
        cCast(getProcTypeCast(m, prc),
          cCall("hcrGetProc",
            getModuleDllPath(m, prc),
            '"' & prc.loc.snippet & '"')))
    genProcPrototype(m, prc)
    if q != nil and not containsOrIncl(q.declaredThings, prc.id):
      # make sure there is a "prototype" in the external module
      # which will actually become a function pointer
      if isReloadable(m, prc):
        genProcPrototype(q, prc)
      # Ask about `q`, the TU the body goes into. Outside a batch `q` IS `m`.
      if emitsBodyInThisModule(q, prc):
        genProcLvl3(q, prc)
  else:
    fillProcLoc(m, son(prc.ast, namePos))
    useHeader(m, prc)
    if sfInfixCall notin prc.flags: genProcPrototype(m, prc)

proc requestConstImpl(p: BProc, sym: PSym) =
  if genConstSetup(p, sym):
    let m = p.module
    # declare implementation:
    let q = findPendingModule(m, sym)
    if q != nil and not containsOrIncl(q.declaredThings, sym.id):
      assert q.initProc.module == q
      genConstDefinition(q, p, sym)
    # declare header:
    if q != m and not containsOrIncl(m.declaredThings, sym.id):
      genConstHeader(m, q, p, sym)

proc isActivated(prc: PSym): bool = prc.typ != nil

proc genProc(m: BModule, prc: PSym) =
  if sfBorrow in prc.flags or not isActivated(prc): return
  if sfForward in prc.flags:
    addForwardedProc(m, prc)
    fillProcLoc(m, son(prc.ast, namePos))
  else:
    genProcLvl2(m, prc)
    if {sfExportc, sfCompilerProc} * prc.flags == {sfExportc} and
        m.g.generatedHeader != nil and lfNoDecl notin prc.loc.flags:
      genProcPrototype(m.g.generatedHeader, prc)
      if prc.typ.callConv == ccInline:
        if not containsOrIncl(m.g.generatedHeader.declaredThings, prc.id):
          genProcLvl3(m.g.generatedHeader, prc)

proc requestProcDef*(m: BModule, prc: PSym) =
  ## Public demand entry: request `prc`'s definition; it is routed to the
  ## module that owns it and generated once, exactly as if some generated
  ## code had referenced it.
  genProc(m, prc)

proc genVarPrototype(m: BModule, n: PNode) =
  #assert(sfGlobal in sym.flags)
  let sym = n.sym
  useHeader(m, sym)
  fillBackendName(m, sym)
  backendEnsureMutable sym
  fillLoc(sym.locImpl, locGlobalVar, n, OnHeap)
  if treatGlobalDifferentlyForHCR(m, sym): incl(sym, lfIndirect)

  if (lfNoDecl in sym.loc.flags) or contains(m.declaredThings, sym.id):
    return
  if not sameOwners(sym.owner, m.module):
    # else we already have the symbol generated!
    assert(sym.loc.snippet != "")
    incl(m.declaredThings, sym.id)
    if sfThread in sym.flags:
      declareThreadVar(m, sym, true)
    else:
      let vis = if m.hcrOn: StaticProc else: Extern
      var typ = getTypeDesc(m, sym.loc.t, dkVar)
      if m.hcrOn:
        typ = ptrType(typ)
      if lfDynamicLib in sym.loc.flags:
        typ = ptrType(typ)
      if sfCodegenDecl in sym.flags:
        m.s[cfsVars].addDeclWithVisibility(vis):
          m.s[cfsVars].addVar(m, sym,
            name = sym.loc.snippet,
            typ = typ)
      else:
        m.s[cfsVars].addVar(m, sym,
          name = sym.loc.snippet,
          typ = typ,
          visibility = vis)
      if m.hcrOn:
        m.initProc.procSec(cpsLocals).add('\t')
        m.initProc.procSec(cpsLocals).addAssignment(sym.loc.snippet,
          cCast(typ,
            cCall("hcrGetGlobal",
              getModuleDllPath(m, sym),
              '"' & sym.loc.snippet & '"')))

proc addNimDefines(result: var Builder; conf: ConfigRef) {.inline.} =
  result.addf("#define NIM_INTBITS $1\L", [
    platform.CPU[conf.target.targetCPU].intSize.rope])
  if conf.cppCustomNamespace.len > 0:
    result.add("#define USE_NIM_NAMESPACE ")
    result.add(conf.cppCustomNamespace)
    result.add("\L")
  if conf.isDefined("nimEmulateOverflowChecks"):
    result.add("#define NIM_EmulateOverflowChecks\L")

proc headerTop(): Rope =
  result = "/* Generated by Nim Compiler v$1 */$N" % [rope(VersionAsString)]

proc getCopyright(conf: ConfigRef; cfile: Cfile): Rope =
  result = headerTop()
  if optCompileOnly notin conf.globalOptions:
    result.add ("/* Compiled for: $1, $2, $3 */$N") %
        [rope(platform.OS[conf.target.targetOS].name),
        rope(platform.CPU[conf.target.targetCPU].name),
        rope(extccomp.CC[conf.cCompiler].name)]
    # The per-module IC backend cannot write this line truthfully. A global
    # `{.passC.}` (system's `-pthread`, say) reaches `conf.compileOptions` only
    # in a process that compiled the module declaring it, and a `cg` process
    # sees one module's import closure — so the command it would print is a
    # partial snapshot, and WHICH part depends on how modules were grouped into
    # processes. Measured on a 67-module program: 2 of 67 `.c` carried
    # `-pthread` at batch size 1, 4 at size 4, 5 at size 8, against 16 of 16 for
    # a whole-program `nim c`. The real command is assembled by the `link`
    # stage, which applies every module's recorded directives first
    # (`replayer.applyBackendActions`) — so the object files were always
    # correct; only this comment was wrong, and non-deterministically so.
    if conf.cmd == cmdNifC and conf.icBackendStage.len > 0:
      result.add "/* Command for C compiler: assembled by the link stage\L" &
                 "   from every module's recorded C directives. */\L"
    else:
      result.add ("/* Command for C compiler:$n   $1 */$N") %
          [rope(getCompileCFileCmd(conf, cfile))]

proc getFileHeader(conf: ConfigRef; cfile: Cfile): Rope =
  var res = newBuilder(getCopyright(conf, cfile))
  if conf.hcrOn: res.add("#define NIM_HOT_CODE_RELOADING\L")
  addNimDefines(res, conf)
  result = extract(res)

proc getSomeNameForModule*(m: BModule): Rope =
  ## Returns a mangled module name.
  assert m.module.kind == skModule
  assert m.module.owner.kind == skPackage
  result = mangleModuleName(m.g.config, m.filename).mangle

proc getSomeInitName(m: BModule, suffix: string): Rope =
  if not m.hcrOn:
    result = getSomeNameForModule(m)
  else:
    result = ""
  result.add suffix

proc getInitName(m: BModule): Rope =
  if sfMainModule in m.module.flags:
    # generate constant name for main module, for "easy" debugging.
    result = rope(m.config.nimMainPrefix) & rope"NimMainModule"
  else:
    result = getSomeInitName(m, "Init000")

proc getDatInitName(m: BModule): Rope = getSomeInitName(m, "DatInit000")
proc getHcrInitName(m: BModule): Rope = getSomeInitName(m, "HcrInit000")

proc hcrGetProcLoadCode(builder: var Builder, m: BModule, sym, prefix, handle, getProcFunc: string)

# The use of a volatile function pointer to call Pre/NimMainInner
# prevents inlining of the NimMainInner function and dependent
# functions, which might otherwise merge their stack frames.
proc isInnerMainVolatile(m: BModule): bool =
  m.config.selectedGC notin {gcNone, gcArc, gcAtomicArc, gcOrc, gcYrc}

proc genPreMain(m: BModule) =
  m.s[cfsProcs].addDeclWithVisibility(Private):
    m.s[cfsProcs].addProcHeader(m.config.nimMainPrefix & "PreMainInner", CVoid, cProcParams())
    m.s[cfsProcs].finishProcHeaderWithBody():
      m.s[cfsProcs].add(extract(m.g.otherModsInit))
  if optNoMain notin m.config.globalOptions:
    m.s[cfsProcs].addDeclWithVisibility(Private):
      m.s[cfsProcs].addVar(name = "cmdCount", typ = CInt)
    m.s[cfsProcs].addDeclWithVisibility(Private):
      m.s[cfsProcs].addVar(name = "cmdLine", typ = ptrType(ptrType(CChar)))
  m.s[cfsProcs].addDeclWithVisibility(Private):
    m.s[cfsProcs].addProcHeader(m.config.nimMainPrefix & "PreMain", CVoid, cProcParams())
    m.s[cfsProcs].finishProcHeaderWithBody():
      if isInnerMainVolatile(m):
        m.s[cfsProcs].addProcVar(name = "inner", rettype = CVoid, params = cProcParams(), isVolatile = true)
        m.s[cfsProcs].addAssignment("inner", m.config.nimMainPrefix & "PreMainInner")
        m.s[cfsProcs].add(extract(m.g.mainDatInit))
        m.s[cfsProcs].addCallStmt(cDeref("inner"))
      else:
        # not volatile
        m.s[cfsProcs].add(extract(m.g.mainDatInit))
        m.s[cfsProcs].addCallStmt(m.config.nimMainPrefix & "PreMainInner")

proc genMainProcs(m: BModule) =
  m.s[cfsProcs].addCallStmt(m.config.nimMainPrefix & "NimMain")

proc genMainProcsWithResult(m: BModule) =
  genMainProcs(m)
  if m.config.cmd != cmdNifC:
    var res = "nim_program_result"
    if m.hcrOn: res = cDeref(res)
    m.s[cfsProcs].addReturn(res)
  else:
    m.s[cfsProcs].addReturn(cIntValue(0))

proc genNimMainInner(m: BModule) =
  m.s[cfsProcs].addDeclWithVisibility(Private):
    m.s[cfsProcs].addProcHeader(ccCDecl, m.config.nimMainPrefix & "NimMainInner", CVoid, cProcParams())
    m.s[cfsProcs].finishProcHeaderWithBody():
      m.s[cfsProcs].add(extract(m.g.mainModInit))
  m.s[cfsProcs].addNewline()

proc initStackBottom(m: BModule): bool =
  not (m.config.target.targetOS == osStandalone or m.config.selectedGC in {gcNone, gcArc, gcAtomicArc, gcOrc, gcYrc})

proc genNimMainProc(m: BModule, preMainCode: Snippet) =
  m.s[cfsProcs].addProcHeader(ccCDecl, m.config.nimMainPrefix & "NimMain", CVoid, cProcParams())
  m.s[cfsProcs].finishProcHeaderWithBody():
    if isInnerMainVolatile(m):
      m.s[cfsProcs].addProcVar(name = "inner", rettype = CVoid, params = cProcParams(), isVolatile = true)
      m.s[cfsProcs].add(preMainCode)
      m.s[cfsProcs].addAssignment("inner", m.config.nimMainPrefix & "NimMainInner")
      if initStackBottom(m):
        m.s[cfsProcs].addCallStmt("initStackBottomWith", cCast(CPointer, cAddr("inner")))
      m.s[cfsProcs].addCallStmt(cDeref("inner"))
    else:
      # not volatile
      m.s[cfsProcs].add(preMainCode)
      if initStackBottom(m):
        m.s[cfsProcs].addCallStmt("initStackBottomWith", cCast(CPointer, cAddr("inner")))
      m.s[cfsProcs].addCallStmt(m.config.nimMainPrefix & "NimMainInner")
  m.s[cfsProcs].addNewline()

proc genNimMainBody(m: BModule, preMainCode: Snippet) =
  genNimMainInner(m)
  genNimMainProc(m, preMainCode)

proc genPosixCMain(m: BModule) =
  m.s[cfsProcs].addProcHeader("main", CInt, cProcParams(
    (name: "argc", typ: CInt),
    (name: "args", typ: ptrType(ptrType(CChar)))))
  m.s[cfsProcs].finishProcHeaderWithBody():
    m.s[cfsProcs].addAssignment("cmdLine", "args")
    m.s[cfsProcs].addAssignment("cmdCount", "argc")
    genMainProcsWithResult(m)
  m.s[cfsProcs].addNewline()

proc genStandaloneCMain(m: BModule) =
  m.s[cfsProcs].addProcHeader("main", CInt, cProcParams())
  m.s[cfsProcs].finishProcHeaderWithBody():
    genMainProcs(m)
    m.s[cfsProcs].addReturn(cIntValue(0))
  m.s[cfsProcs].addNewline()

proc genWinNimMain(m: BModule, preMainCode: Snippet) =
  genNimMainBody(m, preMainCode)

proc genWinCMain(m: BModule) =
  m.s[cfsProcs].addProcHeader(ccStdCall, "WinMain", CInt, cProcParams(
    (name: "hCurInstance", typ: "HINSTANCE"),
    (name: "hPrevInstance", typ: "HINSTANCE"),
    (name: "lpCmdLine", typ: "LPSTR"),
    (name: "nCmdShow", typ: CInt)))
  m.s[cfsProcs].finishProcHeaderWithBody():
    genMainProcsWithResult(m)
  m.s[cfsProcs].addNewline()

proc genWinNimDllMain(m: BModule, preMainCode: Snippet) =
  genNimMainInner(m)
  m.s[cfsProcs].addDeclWithVisibility(ExportLib):
    genNimMainProc(m, preMainCode)

proc genWinCDllMain(m: BModule) =
  # used to use WINAPI macro, now ccStdCall:
  m.s[cfsProcs].addProcHeader(ccStdCall, "DllMain", "BOOL", cProcParams(
    (name: "hinstDLL", typ: "HINSTANCE"),
    (name: "fwdreason", typ: "DWORD"),
    (name: "lpvReserved", typ: "LPVOID")))
  m.s[cfsProcs].finishProcHeaderWithBody():
    m.s[cfsProcs].addSingleIfStmt(removeSinglePar(cOp(Equal, "fwdreason", "DLL_PROCESS_ATTACH"))):
      genMainProcs(m)
    m.s[cfsProcs].addReturn(cIntValue(1))
  m.s[cfsProcs].addNewline()

proc genPosixNimDllMain(m: BModule, preMainCode: Snippet) =
  genWinNimDllMain(m, preMainCode)

proc genPosixCDllMain(m: BModule) =
  # used to use NIM_POSIX_INIT, now uses direct constructor attribute
  m.s[cfsProcs].addProcHeader("NimMainInit", CVoid, cProcParams(), isConstructor = true)
  m.s[cfsProcs].finishProcHeaderWithBody():
    genMainProcs(m)
  m.s[cfsProcs].addNewline()

proc genGenodeNimMain(m: BModule, preMainCode: Snippet) =
  let typName = "Genode::Env"
  m.s[cfsProcs].addDeclWithVisibility(Extern):
    m.s[cfsProcs].addVar(name = "nim_runtime_env", typ = ptrType(typName))
  m.s[cfsProcs].addDeclWithVisibility(ExternC):
    m.s[cfsProcs].addProcHeader("nim_component_construct", CVoid, cProcParams((name: "", typ: ptrType(typName))))
    m.s[cfsProcs].finishProcHeaderAsProto()
  genNimMainBody(m, preMainCode)

proc genComponentConstruct(m: BModule) =
  let fnName = "Libc::Component::construct"
  let typName = "Libc::Env"
  m.s[cfsProcs].addProcHeader(fnName, CVoid, cProcParams((name: "env", typ: cppRefType(typName))))
  m.s[cfsProcs].finishProcHeaderWithBody():
    m.s[cfsProcs].addLineComment("Set Env used during runtime initialization")
    m.s[cfsProcs].addAssignment("nim_runtime_env", cAddr("env"))
    let callFn = "Libc::with_libc"
    var call: CallBuilder
    m.s[cfsProcs].addStmt():
      m.s[cfsProcs].addCall(call, callFn):
        m.s[cfsProcs].addArgument(call):
          m.s[cfsProcs].addCppLambda(ByReference, cProcParams()):
            m.s[cfsProcs].addLineComment("Initialize runtime and globals")
            genMainProcs(m)
            m.s[cfsProcs].addLineComment("Call application construct")
            m.s[cfsProcs].addCallStmt("nim_component_construct", cAddr("env"))
  m.s[cfsProcs].addNewline()

proc genMainProc(m: BModule) =
  ## this function is called in cgenWriteModules after all modules are closed,
  ## it means raising dependency on the symbols is too late as it will not propagate
  ## into other modules, only simple rope manipulations are allowed
  var preMainBuilder = newBuilder("")
  if m.hcrOn:
    proc loadLib(builder: var Builder, handle: string, name: string) =
      let prc = magicsys.getCompilerProc(m.g.graph, name)
      assert prc != nil
      let n = newStrNode(nkStrLit, prc.annex.path.strVal)
      n.info = prc.annex.path.info
      var strLitBuilder = newBuilder("")
      genStringLiteral(m, n, strLitBuilder)
      let strLit = extract(strLitBuilder)
      builder.addAssignment(handle, cCall(cgsymValue(m, "nimLoadLibrary"), strLit))
      builder.addSingleIfStmt(cOp(Not, handle)):
        builder.addCallStmt(cgsymValue(m, "nimLoadLibraryError"), strLit)

    loadLib(preMainBuilder, "hcr_handle", "hcrGetProc")
    if m.config.selectedGC in {gcArc, gcAtomicArc, gcOrc, gcYrc}:
      preMainBuilder.addCallStmt(m.config.nimMainPrefix & "PreMain")
    else:
      preMainBuilder.addVar(name = "rtl_handle", typ = CPointer)
      loadLib(preMainBuilder, "rtl_handle", "nimGC_setStackBottom")
      hcrGetProcLoadCode(preMainBuilder, m, "nimGC_setStackBottom", "nimrtl_", "rtl_handle", "nimGetProcAddr")
      preMainBuilder.addAssignment("inner", m.config.nimMainPrefix & "PreMain")
      preMainBuilder.addCallStmt("initStackBottomWith_actual", cCast(CPointer, cAddr("inner")))
      preMainBuilder.addCallStmt(cDeref("inner"))
  else:
    preMainBuilder.addCallStmt(m.config.nimMainPrefix & "PreMain")
  let preMainCode = extract(preMainBuilder)

  if m.config.target.targetOS == osWindows and
      m.config.globalOptions * {optGenGuiApp, optGenDynLib} != {}:
    m.includeHeader("<windows.h>")
  elif m.config.target.targetOS == osGenode:
    m.includeHeader("<libc/component.h>")

  if initStackBottom(m):
    cgsym(m, "initStackBottomWith")
  inc(m.labels)

  genPreMain(m)

  if m.config.target.targetOS == osWindows and
      m.config.globalOptions * {optGenGuiApp, optGenDynLib} != {}:
    if optGenGuiApp in m.config.globalOptions:
      genWinNimMain(m, preMainCode)
    else:
      genWinNimDllMain(m, preMainCode)
  elif m.config.target.targetOS == osGenode:
    genGenodeNimMain(m, preMainCode)
  elif optGenDynLib in m.config.globalOptions:
    genPosixNimDllMain(m, preMainCode)
  else:
    genNimMainBody(m, preMainCode)

  if optNoMain notin m.config.globalOptions:
    if m.config.cppCustomNamespace.len > 0:
      closeNamespaceNim(m.s[cfsProcs])
      m.s[cfsProcs].add "using namespace " & m.config.cppCustomNamespace & ";\L"

    if m.config.target.targetOS == osWindows and
        m.config.globalOptions * {optGenGuiApp, optGenDynLib} != {}:
      if optGenGuiApp in m.config.globalOptions:
        genWinCMain(m)
      else:
        genWinCDllMain(m)
    elif m.config.target.targetOS == osGenode:
      genComponentConstruct(m)
    elif optGenDynLib in m.config.globalOptions:
      genPosixCDllMain(m)
    elif m.config.target.targetOS == osStandalone:
      genStandaloneCMain(m)
    else:
      genPosixCMain(m)

    if m.config.cppCustomNamespace.len > 0:
      openNamespaceNim(m.config.cppCustomNamespace, m.s[cfsProcs])

proc registerModuleToMain(g: BModuleList; m: BModule) =
  let
    init = m.getInitName
    datInit = m.getDatInitName

  if m.hcrOn:
    var hcrModuleMeta = newBuilder("")
    let systemModulePath = getModuleDllPath(m, g.mods[g.graph.config.m.systemFileIdx.int].module)
    let mainModulePath = getModuleDllPath(m, m.module)
    hcrModuleMeta.addDeclWithVisibility(Private):
      hcrModuleMeta.addArrayVarWithInitializer(kind = Local,
          name = "hcr_module_list",
          elementType = ptrConstType(CChar),
          len = g.graph.importDeps.getOrDefault(FileIndex(m.module.position)).len +
            ord(sfMainModule in m.module.flags) +
            1):
        var modules: StructInitializer
        hcrModuleMeta.addStructInitializer(modules, siArray):
          if sfMainModule in m.module.flags:
            hcrModuleMeta.addField(modules, ""):
              hcrModuleMeta.add(systemModulePath)
          g.graph.importDeps.withValue(FileIndex(m.module.position), deps):
            for curr in deps[]:
              hcrModuleMeta.addField(modules, ""):
                hcrModuleMeta.add(getModuleDllPath(m, g.mods[curr.int].module))
          hcrModuleMeta.addField(modules, ""):
            hcrModuleMeta.add("\"\"")
    hcrModuleMeta.addDeclWithVisibility(ExportLib):
      hcrModuleMeta.addProcHeader(ccNimCall, "HcrGetImportedModules", ptrType(CPointer), cProcParams())
      hcrModuleMeta.finishProcHeaderWithBody():
        hcrModuleMeta.addReturn(cCast(ptrType(CPointer), "hcr_module_list"))
    hcrModuleMeta.addDeclWithVisibility(ExportLib):
      hcrModuleMeta.addProcHeader(ccNimCall, "HcrGetSigHash", ptrType(CChar), cProcParams())
      hcrModuleMeta.finishProcHeaderWithBody():
        hcrModuleMeta.addReturn('"' & $sigHash(m.module, m.config) & '"')
    if sfMainModule in m.module.flags:
      g.mainModProcs.add(extract(hcrModuleMeta))
      g.mainModProcs.addDeclWithVisibility(StaticProc):
        g.mainModProcs.addVar(name = "hcr_handle", typ = CPointer)
      g.mainModProcs.addDeclWithVisibility(ExportLib):
        g.mainModProcs.addProcHeader(ccNimCall, init, CVoid, cProcParams())
        g.mainModProcs.finishProcHeaderAsProto()
      g.mainModProcs.addDeclWithVisibility(ExportLib):
        g.mainModProcs.addProcHeader(ccNimCall, datInit, CVoid, cProcParams())
        g.mainModProcs.finishProcHeaderAsProto()
      g.mainModProcs.addDeclWithVisibility(ExportLib):
        g.mainModProcs.addProcHeaderWithParams(ccNimCall, m.getHcrInitName, CVoid):
          var hcrInitParams: ProcParamBuilder
          g.mainModProcs.addProcParams(hcrInitParams):
            g.mainModProcs.addUnnamedParam(hcrInitParams, CPointer)
            g.mainModProcs.addProcTypedParam(hcrInitParams, ccNimCall, "getProcAddr", CPointer, cProcParams(
              (name: "", typ: CPointer),
              (name: "", typ: ptrType(CChar))))
        g.mainModProcs.finishProcHeaderAsProto()
      g.mainModProcs.addDeclWithVisibility(ExportLib):
        g.mainModProcs.addProcHeader(ccNimCall, "HcrCreateTypeInfos", CVoid, cProcParams())
        g.mainModProcs.finishProcHeaderAsProto()
      g.mainModInit.addCallStmt(init)
      g.otherModsInit.addCallStmt("hcrInit",
        cCast(ptrType(CPointer), "hcr_module_list"),
        mainModulePath,
        systemModulePath,
        datInit,
        "hcr_handle",
        "nimGetProcAddr")
      g.mainDatInit.addCallStmt(m.getHcrInitName, "hcr_handle", "nimGetProcAddr")
      g.mainDatInit.addCallStmt("hcrAddModule", mainModulePath)
      g.mainDatInit.addCallStmt("HcrCreateTypeInfos")
      # nasty nasty hack to get the command line functionality working with HCR
      # register the 2 variables on behalf of the os module which might not even
      # be loaded (in which case it will get collected but that is not a problem)
      # EDIT: indeed, this hack, in combination with another un-necessary one
      # (`makeCString` was doing line wrap of string litterals) was root cause for
      # bug #16265.
      let osModulePath = ($systemModulePath).replace("stdlib_system", "stdlib_os").rope
      g.mainDatInit.addCallStmt("hcrAddModule", osModulePath)
      let cmdCountTyp = ptrType(CInt)
      let cmdLineTyp = ptrType(ptrType(ptrType(CChar)))
      g.mainDatInit.addVar(name = "cmd_count", typ = cmdCountTyp)
      g.mainDatInit.addVar(name = "cmd_line", typ = cmdLineTyp)
      g.mainDatInit.addCallStmt("hcrRegisterGlobal",
        osModulePath,
        "\"cmdCount\"",
        cSizeof(cmdCountTyp),
        CNil,
        cCast(ptrType(CPointer), cAddr("cmd_count")))
      g.mainDatInit.addCallStmt("hcrRegisterGlobal",
        osModulePath,
        "\"cmdLine\"",
        cSizeof(cmdLineTyp),
        CNil,
        cCast(ptrType(CPointer), cAddr("cmd_line")))
      g.mainDatInit.addAssignment(cDeref("cmd_count"), "cmdCount")
      g.mainDatInit.addAssignment(cDeref("cmd_line"), "cmdLine")
    else:
      m.s[cfsInitProc].add(extract(hcrModuleMeta))
    return

  if m.s[cfsDatInitProc].buf.len > 0:
    g.mainModProcs.addDeclWithVisibility(Private):
      g.mainModProcs.addProcHeader(ccNimCall, datInit, CVoid, cProcParams())
      g.mainModProcs.finishProcHeaderAsProto()
    g.mainDatInit.addCallStmt(datInit)

  # Initialization of TLS and GC should be done in between
  # systemDatInit and systemInit calls if any
  if sfSystemModule in m.module.flags:
    if emulatedThreadVars(m.config) and m.config.target.targetOS != osStandalone:
      g.mainDatInit.addCallStmt(cgsymValue(m, "initThreadVarsEmulation"))
    if m.config.target.targetOS != osStandalone and m.config.selectedGC notin {gcNone, gcArc, gcAtomicArc, gcOrc, gcYrc}:
      g.mainDatInit.addCallStmt(cgsymValue(m, "initStackBottomWith"),
        cCast(CPointer, cAddr("inner")))

  if m.s[cfsInitProc].buf.len > 0:
    g.mainModProcs.addDeclWithVisibility(Private):
      g.mainModProcs.addProcHeader(ccNimCall, init, CVoid, cProcParams())
      g.mainModProcs.finishProcHeaderAsProto()
    if sfMainModule in m.module.flags:
      g.mainModInit.addCallStmt(init)
    elif sfSystemModule in m.module.flags:
      g.mainDatInit.addCallStmt(init) # systemInit must called right after systemDatInit if any
    else:
      g.otherModsInit.addCallStmt(init)

proc registerReusedModuleToMain*(g: BModuleList; m: BModule;
                                initRequired, datInitRequired: bool) =
  ## `registerModuleToMain` for a module whose cached translation unit is
  ## reused: the init/datInit presence comes from the artifact's meta head
  ## instead of the (never generated) sections. Mirrors the non-hcr path of
  ## `registerModuleToMain` — reuse is disabled when hcr is on.
  let
    init = m.getInitName
    datInit = m.getDatInitName

  if datInitRequired:
    g.mainModProcs.addDeclWithVisibility(Private):
      g.mainModProcs.addProcHeader(ccNimCall, datInit, CVoid, cProcParams())
      g.mainModProcs.finishProcHeaderAsProto()
    g.mainDatInit.addCallStmt(datInit)

  if sfSystemModule in m.module.flags:
    if emulatedThreadVars(m.config) and m.config.target.targetOS != osStandalone:
      g.mainDatInit.addCallStmt(cgsymValue(m, "initThreadVarsEmulation"))
    if m.config.target.targetOS != osStandalone and m.config.selectedGC notin {gcNone, gcArc, gcAtomicArc, gcOrc, gcYrc}:
      g.mainDatInit.addCallStmt(cgsymValue(m, "initStackBottomWith"),
        cCast(CPointer, cAddr("inner")))

  if initRequired:
    g.mainModProcs.addDeclWithVisibility(Private):
      g.mainModProcs.addProcHeader(ccNimCall, init, CVoid, cProcParams())
      g.mainModProcs.finishProcHeaderAsProto()
    if sfMainModule in m.module.flags:
      g.mainModInit.addCallStmt(init)
    elif sfSystemModule in m.module.flags:
      g.mainDatInit.addCallStmt(init) # systemInit right after systemDatInit
    else:
      g.otherModsInit.addCallStmt(init)

proc genDatInitCode(m: BModule) =
  ## this function is called in cgenWriteModules after all modules are closed,
  ## it means raising dependency on the symbols is too late as it will not propagate
  ## into other modules, only simple rope manipulations are allowed

  var moduleDatInitRequired = m.hcrOn

  var prc = newBuilder("")
  let vis = if m.hcrOn: ExportLib else: Private
  prc.addDeclWithVisibility(vis):
    prc.addProcHeader(ccNimCall, getDatInitName(m), CVoid, cProcParams())
    prc.finishProcHeaderWithBody():
      # we don't want to break into such init code - could happen if a line
      # directive from a function written by the user spills after itself
      genCLineDir(prc, InvalidFileIdx, 999999, m.config)

      for i in cfsTypeInit1..cfsDynLibInit:
        if m.s[i].buf.len != 0:
          moduleDatInitRequired = true
          prc.add(extract(m.s[i]))

  prc.addNewline()

  if moduleDatInitRequired:
    m.s[cfsDatInitProc].add(extract(prc))
    #rememberFlag(m.g.graph, m.module, HasDatInitProc)

# Very similar to the contents of symInDynamicLib - basically only the
# things needed for the hot code reloading runtime procs to be loaded
proc hcrGetProcLoadCode(builder: var Builder, m: BModule, sym, prefix, handle, getProcFunc: string) =
  let prc = magicsys.getCompilerProc(m.g.graph, sym)
  assert prc != nil
  fillProcLoc(m, son(prc.ast, namePos))

  var tmp = mangleDynLibProc(prc)
  backendEnsureMutable prc
  prc.locImpl.snippet = tmp
  prc.typ.sym = nil

  if not containsOrIncl(m.declaredThings, prc.id):
    m.s[cfsVars].addVar(Global, name = prc.loc.snippet, typ = getTypeDesc(m, prc.loc.t, dkVar))

  builder.addAssignment(tmp, cCast(getTypeDesc(m, prc.typ, dkVar),
    cCall(getProcFunc, handle, makeCString(prefix & sym))))

proc genInitCode(m: BModule) =
  ## this function is called in cgenWriteModules after all modules are closed,
  ## it means raising dependency on the symbols is too late as it will not propagate
  ## into other modules, only simple rope manipulations are allowed
  var moduleInitRequired = m.hcrOn
  let initname = getInitName(m)
  var prcBody = newBuilder("")
  # we don't want to break into such init code - could happen if a line
  # directive from a function written by the user spills after itself
  genCLineDir(prcBody, InvalidFileIdx, 999999, m.config)
  if m.typeNodes > 0:
    if m.hcrOn:
      m.s[cfsTypeInit1].addVar(name = m.typeNodesName, typ = ptrType(cgsymValue(m, "TNimNode")))
      m.s[cfsTypeInit1].addCallStmt("hcrRegisterGlobal",
        getModuleDllPath(m, m.module),
        '"' & m.typeNodesName & '_' & $m.typeNodes & '"',
        cOp(Mul, NimInt, cSizeof("TNimNode"), cIntValue(m.typeNodes)),
        CNil,
        cCast(ptrType(CPointer), cAddr(m.typeNodesName)))
    else:
      m.s[cfsTypeInit1].addArrayVar(Global, name = m.typeNodesName,
        elementType = cgsymValue(m, "TNimNode"), len = m.typeNodes)
  if m.nimTypes > 0:
    m.s[cfsTypeInit1].addArrayVar(Global, name = m.nimTypesName,
      elementType = cgsymValue(m, "TNimType"), len = m.nimTypes)

  if m.hcrOn:
    prcBody.addVar(name = "nim_hcr_dummy_", typ = ptrType(CInt), initializer = cIntValue(0))
    prcBody.addVar(name = "nim_hcr_do_init_", typ = NimBool,
      initializer = cCall("hcrRegisterGlobal",
        getModuleDllPath(m, m.module),
        "\"module_initialized_\"",
        cIntValue(1),
        CNil,
        cCast(ptrType(CPointer), cAddr("nim_hcr_dummy_"))))

  template writeSection(thing: untyped, section: TCProcSection, addHcrGuards = false) =
    if m.thing.s(section).buf.len > 0:
      moduleInitRequired = true
      if addHcrGuards:
        prcBody.addSingleIfStmt("nim_hcr_do_init_"):
          prcBody.addNewline()
          prcBody.add(extract(m.thing.s(section)))
          prcBody.addNewline()
      else:
        prcBody.add(extract(m.thing.s(section)))

  #echo "PRE INIT PROC ", m.module.name.s, " ", m.s[cfsVars].buf.len

  if m.preInitProc.s(cpsInit).buf.len > 0 or m.preInitProc.s(cpsStmts).buf.len > 0:
    # Give this small function its own scope
    prcBody.addScope():
      # Keep a bogus frame in case the code needs one
      prcBody.addVar(name = "FR_", typ = "TFrame")
      prcBody.addFieldAssignment("FR_", "len", cIntValue(0))

      writeSection(preInitProc, cpsLocals)
      writeSection(preInitProc, cpsInit, m.hcrOn)
      writeSection(preInitProc, cpsStmts)
    when false:
      m.initProc.blocks[0].sections[cpsLocals].add m.preInitProc.s(cpsLocals)
      m.initProc.blocks[0].sections[cpsInit].prepend m.preInitProc.s(cpsInit)
      m.initProc.blocks[0].sections[cpsStmts].prepend m.preInitProc.s(cpsStmts)

  # add new scope for following code, because old vcc compiler need variable
  # be defined at the top of the block
  prcBody.addScope():
    writeSection(initProc, cpsLocals)

    if m.initProc.s(cpsInit).buf.len > 0 or m.initProc.s(cpsStmts).buf.len > 0:
      moduleInitRequired = true
      if optStackTrace in m.initProc.options and frameDeclared notin m.flags:
        # BUT: the generated init code might depend on a current frame, so
        # declare it nevertheless:
        incl m.flags, frameDeclared
        if preventStackTrace notin m.flags:
          var procname = makeCString(m.module.name.s)
          prcBody.add(initFrame(m.initProc, procname, quotedFilename(m.config, m.module.info)))
        else:
          prcBody.addVar(name = "FR_", typ = "TFrame")
          prcBody.addFieldAssignment("FR_", "len", cIntValue(0))

      writeSection(initProc, cpsInit, m.hcrOn)
      writeSection(initProc, cpsStmts)

      if beforeRetNeeded in m.initProc.flags:
        prcBody.addLabel("BeforeRet_")

      if m.config.exc == excGoto:
        if getCompilerProc(m.g.graph, "nimTestErrorFlag") != nil:
          prcBody.addCallStmt(cgsymValue(m, "nimTestErrorFlag"))

      if optStackTrace in m.initProc.options and preventStackTrace notin m.flags:
        prcBody.add(deinitFrame(m.initProc))

  var procs = newBuilder("")
  let vis = if m.hcrOn: ExportLib else: Private
  procs.addDeclWithVisibility(vis):
    procs.addProcHeader(ccNimCall, initname, CVoid, cProcParams())
    procs.finishProcHeaderWithBody():
      procs.add(extract(prcBody))

  # we cannot simply add the init proc to ``m.s[cfsProcs]`` anymore because
  # that would lead to a *nesting* of merge sections which the merger does
  # not support. So we add it to another special section: ``cfsInitProc``

  if m.hcrOn:
    var procsToLoad = @["hcrRegisterProc", "hcrGetProc", "hcrRegisterGlobal", "hcrGetGlobal"]

    m.s[cfsInitProc].addDeclWithVisibility(ExportLib):
      m.s[cfsInitProc].addProcHeaderWithParams(ccNimCall, getHcrInitName(m), CVoid):
        var hcrInitParams: ProcParamBuilder
        m.s[cfsInitProc].addProcParams(hcrInitParams):
          m.s[cfsInitProc].addParam(hcrInitParams, "handle", CPointer)
          m.s[cfsInitProc].addProcTypedParam(hcrInitParams, ccNimCall, "getProcAddr", CPointer, cProcParams(
            (name: "", typ: CPointer),
            (name: "", typ: ptrType(CChar))))
      m.s[cfsInitProc].finishProcHeaderWithBody():
        if sfMainModule in m.module.flags:
          # additional procs to load
          procsToLoad.add("hcrInit")
          procsToLoad.add("hcrAddModule")
        # load procs
        for curr in procsToLoad:
          hcrGetProcLoadCode(m.s[cfsInitProc], m, curr, "", "handle", "getProcAddr")

  for i, el in pairs(m.extensionLoaders):
    if el.buf.len != 0:
      moduleInitRequired = true
      procs.addDeclWithVisibility(ExternC):
        procs.addProcHeader(ccNimCall, "nimLoadProcs" & $(i.ord - '0'.ord), CVoid, cProcParams())
        procs.finishProcHeaderWithBody():
          procs.add(extract(el))

  if moduleInitRequired or sfMainModule in m.module.flags:
    m.s[cfsInitProc].add(extract(procs))
    #rememberFlag(m.g.graph, m.module, HasModuleInitProc)

  genDatInitCode(m)

  if m.hcrOn:
    m.s[cfsInitProc].addDeclWithVisibility(ExportLib):
      m.s[cfsInitProc].addProcHeader(ccNimCall, "HcrCreateTypeInfos", CVoid, cProcParams())
      m.s[cfsInitProc].finishProcHeaderWithBody():
        m.s[cfsInitProc].add(extract(m.hcrCreateTypeInfosProc))
    m.s[cfsInitProc].addNewline()

  registerModuleToMain(m.g, m)

proc postprocessCode(conf: ConfigRef, r: var Rope) =
  # find the first directive
  var f = r.find(postprocessDirStart)
  if f == -1:
    return

  var
    nimlnDirLastF = ""

  var res: Rope = r.substr(0, f - 1)
  while f != -1:
    var
      e = r.find(postprocessDirEnd, f + 1)
      dir = r.substr(f + 1, e - 1).split(postprocessDirSep)
    case dir[0]
    of "nimln":
      if dir[2] == nimlnDirLastF:
        res.add("nimln_(" & dir[1] & ");")
      else:
        res.add("nimlf_(" & dir[1] & ", " & quotedFilename(conf, dir[2].parseInt.FileIndex) & ");")
        nimlnDirLastF = dir[2]
    else:
      raiseAssert "unexpected postprocess directive"

    # find the next directive
    f = r.find(postprocessDirStart, e + 1)
    # copy the code until the next directive
    if f != -1:
      res.add(r.substr(e + 1, f - 1))
    else:
      res.add(r.substr(e + 1))

  r = res

proc genModule(m: BModule, cfile: Cfile): Rope =
  var moduleIsEmpty = true

  var res = newBuilder(getFileHeader(m.config, cfile))

  generateThreadLocalStorage(m)
  generateHeaders(m)
  res.add(extract(m.s[cfsHeaders]))
  if m.config.cppCustomNamespace.len > 0:
    openNamespaceNim(m.config.cppCustomNamespace, res)
  if m.s[cfsFrameDefines].buf.len > 0:
    res.add(extract(m.s[cfsFrameDefines]))

  for i in cfsForwardTypes..cfsProcs:
    if m.s[i].buf.len > 0:
      moduleIsEmpty = false
      res.add(extract(m.s[i]))

  # what `registerModuleToMain` will announce for this module; recorded in
  # the artifact's meta head so a later run can reuse the TU
  let initRequired = m.s[cfsInitProc].buf.len > 0
  let datInitRequired = m.s[cfsDatInitProc].buf.len > 0

  if m.config.cmd == cmdNifC:
    # close the definitions section: the init procs that follow belong to
    # the artifact's top level (always-run code, hence liveness roots)
    res.add(cnifEndDefs())

  if m.s[cfsInitProc].buf.len > 0:
    moduleIsEmpty = false
    res.add(extract(m.s[cfsInitProc]))
  if m.s[cfsDatInitProc].buf.len > 0 or m.hcrOn:
    moduleIsEmpty = false
    res.add(extract(m.s[cfsDatInitProc]))

  if m.config.cppCustomNamespace.len > 0:
    closeNamespaceNim(res)

  result = extract(res)
  if optLineDir in m.config.options:
    var srcFileDefs = ""
    for fi in 0..m.config.m.fileInfos.high:
      srcFileDefs.add("#define FX_" & $fi & " " & makeSingleLineCString(toFullPath(m.config, fi.FileIndex)) & "\n")
    result = srcFileDefs & result

  if moduleIsEmpty:
    result = ""

  postprocessCode(m.config, result)

  if m.config.cmd == cmdNifC and result.len > 0:
    let artifact = cfile.cname.string & ".nif"
    var implDeps: seq[string] = @[]
    for pos in m.icImplMods.items:
      if pos != m.module.position:
        implDeps.add modname(pos, m.config)
    sort implDeps
    writeCnifArtifact(result, artifact, initRequired, datInitRequired,
                      m.icDataDefs,
                      semmedNif = toNifFilename(m.config, FileIndex m.module.position),
                      moduleBase = getSomeNameForModule(m),
                      globalDtor = m.icGlobalDtorName,
                      implDeps = implDeps)
    m.g.graph.icCnifFiles.add artifact
  # NB: under cmdNifC the returned text still carries the cnif marks; the
  # caller renders it (dropping dead definitions) or strips it.

proc initProcOptions(m: BModule): TOptions =
  let opts = m.config.options
  if sfSystemModule in m.module.flags: opts-{optStackTrace} else: opts

proc rawNewModule(g: BModuleList; module: PSym, filename: AbsoluteFile): BModule =
  new(result)
  result.g = g
  result.tmpBase = rope("TM" & $hashOwner(module) & "_")
  result.headerFiles = @[]
  result.declaredThings = initIntSet()
  result.declaredProtos = initIntSet()
  result.emittedContentDefs = initHashSet[string]()
  result.icImplMods = initIntSet()
  result.cfilename = filename
  result.filename = filename
  result.typeCache = initTable[SigHash, Rope]()
  result.forwTypeCache = initTable[SigHash, Rope]()
  result.module = module
  result.typeInfoMarker = initTable[SigHash, Rope]()
  result.sigConflicts = initCountTable[SigHash]()
  result.initProc = newProc(nil, result)
  for i in low(result.s)..high(result.s): result.s[i] = newBuilder("")
  result.initProc.options = initProcOptions(result)
  result.preInitProc = newProc(nil, result)
  result.preInitProc.flags.incl nimErrorFlagDisabled
  result.preInitProc.labels = 100_000 # little hack so that unique temporaries are generated
  result.hcrCreateTypeInfosProc = newBuilder("")
  result.dataCache = initNodeTable()
  result.typeStack = @[]
  result.typeNodesName = getTempName(result)
  result.nimTypesName = getTempName(result)
  # no line tracing for the init sections of the system module so that we
  # don't generate a TFrame which can confuse the stack bottom initialization:
  if sfSystemModule in module.flags:
    incl result.flags, preventStackTrace
    excl(result.preInitProc.options, optStackTrace)

proc rawNewModule(g: BModuleList; module: PSym; conf: ConfigRef): BModule =
  result = rawNewModule(g, module, AbsoluteFile toFullPath(conf, module.position.FileIndex))

proc newModule(g: BModuleList; module: PSym; conf: ConfigRef; idgen: IdGenerator): BModule =
  # we should create only one cgen module for each module sym
  result = rawNewModule(g, module, conf)
  result.idgen = idgen
  if module.position >= g.mods.len:
    setLen(g.mods, module.position + 1)
  #growCache g.modules, module.position
  g.mods[module.position] = result

template injectG() {.dirty.} =
  if graph.backend == nil:
    graph.backend = newModuleList(graph)
  let g = BModuleList(graph.backend)

proc setupCgen*(graph: ModuleGraph; module: PSym; idgen: IdGenerator): PPassContext =
  injectG()
  result = newModule(g, module, graph.config, idgen)
  if optGenIndex in graph.config.globalOptions and g.generatedHeader == nil:
    let f = if graph.config.headerFile.len > 0: AbsoluteFile graph.config.headerFile
            else: graph.config.projectFull
    g.generatedHeader = rawNewModule(g, module,
      changeFileExt(completeCfilePath(graph.config, f), hExt))
    incl g.generatedHeader.flags, isHeaderFile

proc writeHeader(m: BModule) =
  var result = newBuilder(headerTop())
  var guard = "__$1__" % [m.filename.splitFile.name.rope]
  result.addf("#ifndef $1$n#define $1$n", [guard])
  addNimDefines(result, m.config)
  generateHeaders(m)

  generateThreadLocalStorage(m)
  for i in cfsHeaders..cfsProcs:
    result.add(extract(m.s[i]))
    if m.config.cppCustomNamespace.len > 0 and i == cfsHeaders:
      openNamespaceNim(m.config.cppCustomNamespace, result)
  result.add(extract(m.s[cfsInitProc]))

  let vis = if optGenDynLib in m.config.globalOptions: ImportLib else: None
  result.addDeclWithVisibility(vis):
    result.addProcHeader(ccCDecl, m.config.nimMainPrefix & "NimMain", CVoid, cProcParams())
    result.finishProcHeaderAsProto()
  if m.config.cppCustomNamespace.len > 0: closeNamespaceNim(result)
  result.addf("#endif /* $1 */$n", [guard])
  var headerText = extract(result)
  if m.config.cmd == cmdNifC:
    headerText = stripCnifMarks(headerText)
  if not writeRope(headerText, m.filename):
    rawMessage(m.config, errCannotOpenFile, m.filename.string)

proc getCFile*(m: BModule): AbsoluteFile =
  let ext =
      if m.compileToCpp: ".nim.cpp"
      elif m.config.backend == backendObjc or sfCompileToObjc in m.module.flags: ".nim.m"
      else: icCFileExt(m.config)
  result = changeFileExt(completeCfilePath(m.config, mangleModuleName(m.config, m.cfilename).AbsoluteFile), ext)

when false:
  proc myOpenCached(graph: ModuleGraph; module: PSym, rd: PRodReader): PPassContext =
    injectG()
    var m = newModule(g, module, graph.config)
    readMergeInfo(getCFile(m), m)
    result = m

proc addHcrInitGuards(p: BProc; n: PNode, inInitGuard: var bool, init: var IfBuilder) =
  if n.kind == nkStmtList:
    for child in sons(n):
      addHcrInitGuards(p, child, inInitGuard, init)
  else:
    let stmtShouldExecute = n.kind in {nkVarSection, nkLetSection} or
                            nfExecuteOnReload in n.flags
    if inInitGuard:
      if stmtShouldExecute:
        endBlockWith(p):
          finishBranch(p.s(cpsStmts), init)
          finishIfStmt(p.s(cpsStmts), init)
        inInitGuard = false
    else:
      if not stmtShouldExecute:
        startBlockWith(p):
          init = initIfStmt(p.s(cpsStmts))
          initElifBranch(p.s(cpsStmts), init, "nim_hcr_do_init_")
        inInitGuard = true

    genStmts(p, n)

proc handleProcGlobals(m: BModule) =
  var procGlobals: seq[PNode] = move m.g.graph.procGlobals

  for i in 0..<procGlobals.len:
    var stmts = newBuilder("")

    # fixes recursive calls #24997
    swap stmts, m.preInitProc.s(cpsStmts)
    var transformedN = procGlobals[i]
    if sfInjectDestructors in m.module.flags:
      transformedN = injectDestructorCalls(m.g.graph, m.idgen, m.module, transformedN)
    genStmts(m.preInitProc, transformedN)
    swap stmts, m.preInitProc.s(cpsStmts)

    handleProcGlobals(m)
    m.preInitProc.s(cpsStmts).add stmts.extract()

proc genTopLevelStmt*(m: BModule; n: PNode) =
  ## Also called from `ic/cbackend.nim`.
  if pipelineutils.skipCodegen(m.config, n): return
  m.initProc.options = initProcOptions(m)
  #softRnl = if optLineDir in m.config.options: noRnl else: rnl
  # XXX replicate this logic!
  var transformedN = transformStmt(m.g.graph, m.idgen, m.module, n)
  if sfInjectDestructors in m.module.flags:
    transformedN = injectDestructorCalls(m.g.graph, m.idgen, m.module, transformedN)

  if m.hcrOn:
    addHcrInitGuards(m.initProc, transformedN, m.inHcrInitGuard, m.hcrInitGuard)
  else:
    genProcBody(m.initProc, transformedN)

  handleProcGlobals(m)

proc shouldRecompile(m: BModule; code: Rope, cfile: Cfile): bool =
  if optForceFullMake notin m.config.globalOptions:
    if not equalsFile(code, cfile.cname):
      when false:
        #m.config.symbolFiles == readOnlySf: #isDefined(m.config, "nimdiff"):
        if fileExists(cfile.cname):
          copyFile(cfile.cname.string, cfile.cname.string & ".backup")
          echo "diff ", cfile.cname.string, ".backup ", cfile.cname.string
        else:
          echo "new file ", cfile.cname.string
      if not writeRope(code, cfile.cname):
        rawMessage(m.config, errCannotOpenFile, cfile.cname.string)
      result = true
    elif fileExists(cfile.obj) and os.fileNewer(cfile.obj.string, cfile.cname.string):
      result = false
    else:
      result = true
  else:
    if not writeRope(code, cfile.cname):
      rawMessage(m.config, errCannotOpenFile, cfile.cname.string)
    result = true

proc genModuleCode(m: BModule; cf: var Cfile): string =
  ## First half of `writeModule`: finalizes the module and produces its code
  ## text. Under cmdNifC the text still carries the cnif marks.
  genInitCode(m)

  while m.queue.len > 0:
    let sym = m.queue.pop()
    genProcLvl2(m, sym)

  finishTypeDescriptions(m)
  if sfMainModule in m.module.flags:
    # generate main file:
    genMainProc(m)
    m.s[cfsProcHeaders].add(extract(m.g.mainModProcs))
    generateThreadVarsSize(m)

  result = genModule(m, cf)

proc registerModuleCode(m: BModule; cf: var Cfile; code: string) =
  ## Second half of `writeModule`: writes the .c file if it changed and
  ## registers it for compilation.
  ##
  ## NOT under the per-module backend's `cg` stage. There the `.c` belongs to
  ## `emit`, which renders it from the `.c.nif` using the GLOBAL merge decision;
  ## `cg` can only filter by the liveness its own process can see, so writing
  ## here puts a second, differently-filtered `.c` at the very path `emit`
  ## declares as its nifmake output. Two stages then claim one output, and the
  ## `.c` ends up newer than `emit`'s own `.c.nif` input — so any build in which
  ## `emit` is not forced to run anyway keeps `cg`'s unfiltered text and hands it
  ## to the linker ("multiple definition of eqdup__…").
  ##
  ## Today nothing surfaces this: `merge` rewrites the decision file on every
  ## run and every `emit` lists it as an input, so all of them re-fire and
  ## overwrite the stray file. That makes the fire-all load-bearing rather than
  ## the "insurance" it is documented as, and it silently blocks making the
  ## decision content-stable. `cg`'s product is the `.c.nif`; the compile
  ## registration is likewise the `link` stage's job.
  if m.config.cmd == cmdNifC and m.config.icBackendStage == "cg": return
  if code != "" or m.config.symbolFiles != disabledSf:
    when hasTinyCBackend:
      if m.config.cmd == cmdTcc:
        tccgen.compileCCode($code, m.config)
        return

    if not shouldRecompile(m, code, cf): cf.flags = {CfileFlag.Cached}
    addFileToCompile(m.config, cf)

proc writeModule(m: BModule) =
  let cfile = getCFile(m)
  var cf = Cfile(nimname: m.module.name.s, cname: cfile,
                  obj: completeCfilePath(m.config, toObjFile(m.config, cfile)), flags: {})
  var code = genModuleCode(m, cf)
  if m.config.cmd == cmdNifC:
    code = stripCnifMarks(code)
  registerModuleCode(m, cf, code)

proc generateLibraryDestroyGlobals(graph: ModuleGraph; m: BModule; body: PNode; isDynlib: bool): PSym =
  let prefixedName = m.config.nimMainPrefix & "NimDestroyGlobals"
  let procname = getIdent(graph.cache, prefixedName)
  result = newSym(skProc, procname, m.idgen, m.module.owner, m.module.info)
  result.typ = newProcType(m.module.info, m.idgen, result)
  result.typ.callConv = ccCDecl
  backendEnsureMutable result
  incl result.flagsImpl, sfExportc
  result.locImpl.snippet = prefixedName
  if isDynlib:
    incl(result.locImpl.flags, lfExportLib)

  let theProc = newNodeI(nkProcDef, m.module.info, bodyPos+1)
  for i in 0..<theProc.len: theProc[i] = newNodeI(nkEmpty, m.module.info)
  theProc[namePos] = newSymNode(result)
  theProc[bodyPos] = body
  result.ast = theProc

proc genIcModuleDestroyGlobals*(graph: ModuleGraph; m: BModule): string =
  ## Per-module backend (`cg` stage), non-main module: wrap this module's
  ## accumulated top-level global destructors in a nullary exported proc and
  ## return its C name ("" when there are none).
  ##
  ## `graph.globalDestructors` is filled while a module's own `cg` process
  ## injects destructors into its top level, but the teardown code is emitted
  ## by the MAIN module's `cg` — a different process, whose `graph` only ever
  ## sees its own entries. So each module emits its own teardown here and
  ## records the name in its `.c.nif` meta head; the main module's `cg` reads
  ## the heads (like it already does for init/datInit) and calls them.
  result = ""
  if graph.globalDestructors.len == 0: return
  var body = newNodeI(nkStmtList, m.module.info)
  for i in countdown(high(graph.globalDestructors), 0):
    body.add graph.globalDestructors[i]
  body.flags.incl nfTransf # should not be further transformed
  graph.globalDestructors.setLen 0

  result = m.config.nimMainPrefix & "NimDestroyGlobals__" & $getSomeNameForModule(m)
  let procname = getIdent(graph.cache, result)
  var dtor = newSym(skProc, procname, m.idgen, m.module.owner, m.module.info)
  dtor.typ = newProcType(m.module.info, m.idgen, dtor)
  dtor.typ.callConv = ccNimCall
  backendEnsureMutable dtor
  incl dtor.flagsImpl, sfExportc # a root for the merge stage's DCE: nothing
                                 # inside this TU calls it, only main does
  dtor.locImpl.snippet = result

  let theProc = newNodeI(nkProcDef, m.module.info, bodyPos+1)
  for i in 0..<theProc.len: theProc[i] = newNodeI(nkEmpty, m.module.info)
  theProc[namePos] = newSymNode(dtor)
  theProc[bodyPos] = body
  dtor.ast = theProc
  genProcLvl3(m, dtor)

proc finalCodegenActions*(graph: ModuleGraph; m: BModule; n: PNode) =
  ## Also called from IC.
  if sfMainModule in m.module.flags:
    # phase ordering problem here: We need to announce this
    # dependency to 'nimTestErrorFlag' before system.c has been written to disk.
    if m.config.exc == excGoto and getCompilerProc(graph, "nimTestErrorFlag") != nil:
      cgsym(m, "nimTestErrorFlag")

    if {optGenStaticLib, optGenDynLib, optNoMain} * m.config.globalOptions == {}:
      for i in countdown(high(graph.globalDestructors), 0):
        n.add graph.globalDestructors[i]
    else:
      var body = newNodeI(nkStmtList, m.module.info)
      for i in countdown(high(graph.globalDestructors), 0):
        body.add graph.globalDestructors[i]
      body.flags.incl nfTransf # should not be further transformed
      let dtor = generateLibraryDestroyGlobals(graph, m, body, optGenDynLib in m.config.globalOptions)
      genProcLvl3(m, dtor)
  if pipelineutils.skipCodegen(m.config, n): return

  # if the module is cached, we don't regenerate the main proc
  # nor the dispatchers? But if the dispatchers changed?
  # XXX emit the dispatchers into its own .c file?
  if n != nil:
    m.initProc.options = initProcOptions(m)
    genProcBody(m.initProc, n)

  if graph.icModuleDtors.len > 0 and sfMainModule in m.module.flags and
      {optGenStaticLib, optGenDynLib, optNoMain} * m.config.globalOptions == {}:
    # Per-module backend: the other modules' top-level global destructors were
    # emitted into their own TUs (`genIcModuleDestroyGlobals`); call them from
    # the end of the main module's init proc — which IS the program body — right
    # after main's own destructors, in the order `generateCgStage` computed
    # (reverse dependency order, mirroring whole-program cgen's single reversed
    # `globalDestructors` list). The lib/noMain flavour — where the whole-program
    # backend collects the destructors into an exported `NimDestroyGlobals`
    # instead — is not reachable: `nim ic` only builds executables.
    for dn in graph.icModuleDtors:
      m.g.mainModProcs.addDeclWithVisibility(Private):
        m.g.mainModProcs.addProcHeader(ccNimCall, dn, CVoid, cProcParams())
        m.g.mainModProcs.finishProcHeaderAsProto()
      m.initProc.s(cpsStmts).addCallStmt(markCName(dn))

  if m.hcrOn:
    # make sure this is pulled in (meaning hcrGetGlobal() is called for it during init)
    let sym = magicsys.getCompilerProc(m.g.graph, "programResult")
    # ignore when not available, could be a module imported early in `system`
    if sym != nil:
      cgsymImpl m, sym
    if m.inHcrInitGuard:
      endBlockWith(m.initProc):
        finishBranch(m.initProc.s(cpsStmts), m.hcrInitGuard)
        finishIfStmt(m.initProc.s(cpsStmts), m.hcrInitGuard)

  if sfMainModule in m.module.flags:
    if m.hcrOn:
      # pull ("define" since they are inline when HCR is on) these functions in the main file
      # so it can load the HCR runtime and later pass the library handle to the HCR runtime which
      # will in turn pass it to the other modules it initializes so they can initialize the
      # register/get procs so they don't have to have the definitions of these functions as well
      cgsym(m, "nimLoadLibrary")
      cgsym(m, "nimLoadLibraryError")
      cgsym(m, "nimGetProcAddr")
      cgsym(m, "procAddrError")
      cgsym(m, "rawWrite")

    # raise dependencies on behalf of genMainProc
    if m.config.target.targetOS != osStandalone and m.config.selectedGC notin {gcNone, gcArc, gcAtomicArc, gcOrc, gcYrc}:
      cgsym(m, "initStackBottomWith")
    if emulatedThreadVars(m.config) and m.config.target.targetOS != osStandalone:
      cgsym(m, "initThreadVarsEmulation")

    if m.g.forwardedProcs.len == 0:
      incl m.flags, objHasKidsValid
    if m.config.cmd == cmdNifC:
      # nifbackend synthesizes the dispatchers between the module loop
      # and the finish loop (emitMethodDispatchers): TUs demand-created
      # by the dispatcher bodies must still reach `modulesClosed`
      discard
    elif optMultiMethods in m.g.config.globalOptions or
        m.g.config.selectedGC notin {gcArc, gcOrc, gcAtomicArc, gcYrc} or
        vtables notin m.g.config.features:
      generateIfMethodDispatchers(graph, m.idgen)


  let mm = m
  m.g.modulesClosed.add mm

proc genForwardedProcs(g: BModuleList) =
  # Forward declared proc:s lack bodies when first encountered, so they're given
  # a second pass here
  # Note: ``genProcLvl2`` may add to ``forwardedProcs``
  while g.forwardedProcs.len > 0:
    let prc = g.forwardedProcs.pop()
    let m = g.mods[prc.itemId.module]
    if sfForward in prc.flags:
      internalError(m.config, prc.info, "still forwarded: " & prc.name.s)

    genProcLvl2(m, prc)

proc cgenWriteModules*(backend: RootRef, config: ConfigRef) =
  let g = BModuleList(backend)
  g.config = config

  # we need to process the transitive closure because recursive module
  # deps are allowed (and the system module is processed in the wrong
  # order anyway)
  genForwardedProcs(g)

  if config.cmd == cmdNifC and not isDefined(config, "icNoCDce"):
    # Two-phase write: produce every module's marked text and artifact
    # first, then compute global liveness over the artifacts and render
    # the .c files with dead definitions dropped. Demand-driven codegen
    # over-approximates (it cannot retract a definition once some path
    # requested it); this is where the surplus is removed.
    var mods: seq[BModule] = @[]
    var cfs: seq[Cfile] = @[]
    var codes: seq[string] = @[]
    for m in cgenModules(g):
      let cfile = getCFile(m)
      var cf = Cfile(nimname: m.module.name.s, cname: cfile,
                     obj: completeCfilePath(m.config, toObjFile(m.config, cfile)), flags: {})
      let code = genModuleCode(m, cf)
      mods.add m
      cfs.add cf
      codes.add code
    let cl = computeLiveFromCArtifacts(g.graph.icCnifFiles)
    var dropped = 0
    for i in 0..<mods.len:
      let rendered =
        if cl.broken: stripCnifMarks(codes[i])
        else: renderMarkedC(codes[i], cl.live, dropped)
      registerModuleCode(mods[i], cfs[i], rendered)
  else:
    for m in cgenModules(g):
      m.writeModule()
  writeMapping(config, g.mapping)
  if g.generatedHeader != nil: writeHeader(g.generatedHeader)