diff --git a/compiler/ast.nim b/compiler/ast.nim
index 9e8d5443233ae..f81dc443dcae3 100644
--- a/compiler/ast.nim
+++ b/compiler/ast.nim
@@ -745,7 +745,7 @@ const
     mEqSet, mLeSet, mLtSet, mMulSet, mPlusSet, mMinusSet,
     mConStrStr, mAppendStrCh, mAppendStrStr, mAppendSeqElem,
     mInSet, mRepr, mOpenArrayToSeq}
-  
+
   generatedMagics* = {mNone, mIsolate, mFinished, mOpenArrayToSeq}
     ## magics that are generated as normal procs in the backend
 
@@ -1504,7 +1504,7 @@ proc mergeLoc(a: var TLoc, b: TLoc) =
   if a.storage == low(typeof(a.storage)): a.storage = b.storage
   a.flags.incl b.flags
   if a.lode == nil: a.lode = b.lode
-  if a.r == nil: a.r = b.r
+  if a.r == "": a.r = b.r
 
 proc newSons*(father: Indexable, length: int) =
   setLen(father.sons, length)
diff --git a/compiler/astalgo.nim b/compiler/astalgo.nim
index d0e30dfb6711c..28c38129ebeb5 100644
--- a/compiler/astalgo.nim
+++ b/compiler/astalgo.nim
@@ -12,9 +12,11 @@
 # the data structures here are used in various places of the compiler.
 
 import
-  ast, hashes, intsets, strutils, options, lineinfos, ropes, idents, rodutils,
+  ast, hashes, intsets, options, lineinfos, ropes, idents, rodutils,
   msgs
 
+import strutils except addf
+
 when defined(nimPreviewSlimSystem):
   import std/assertions
 
@@ -258,7 +260,7 @@ proc makeYamlString*(s: string): Rope =
   # this could trigger InternalError(111). See the ropes module for
   # further information.
   const MaxLineLength = 64
-  result = nil
+  result = ""
   var res = "\""
   for i in 0..<s.len:
     if (i + 1) mod MaxLineLength == 0:
@@ -274,9 +276,9 @@ proc flagsToStr[T](flags: set[T]): Rope =
   if flags == {}:
     result = rope("[]")
   else:
-    result = nil
+    result = ""
     for x in items(flags):
-      if result != nil: result.add(", ")
+      if result != "": result.add(", ")
       result.add(makeYamlString($x))
     result = "[" & result & "]"
 
diff --git a/compiler/ccgcalls.nim b/compiler/ccgcalls.nim
index 05be51a45ab51..ed5a5b0797c9c 100644
--- a/compiler/ccgcalls.nim
+++ b/compiler/ccgcalls.nim
@@ -77,12 +77,12 @@ proc fixupCall(p: BProc, le, ri: PNode, d: var TLoc,
                callee, params: Rope) =
   let canRaise = p.config.exc == excGoto and canRaiseDisp(p, ri[0])
   genLineDir(p, ri)
-  var pl = callee & ~"(" & params
+  var pl = callee & "(" & params
   # getUniqueType() is too expensive here:
   var typ = skipTypes(ri[0].typ, abstractInst)
   if typ[0] != nil:
     if isInvalidReturnType(p.config, typ):
-      if params != nil: pl.add(~", ")
+      if params.len != 0: pl.add(", ")
       # beware of 'result = p(result)'. We may need to allocate a temporary:
       if d.k in {locTemp, locNone} or not preventNrvo(p, d.lode, le, ri):
         # Great, we can use 'd':
@@ -91,18 +91,18 @@ proc fixupCall(p: BProc, le, ri: PNode, d: var TLoc,
           # reset before pass as 'result' var:
           discard "resetLoc(p, d)"
         pl.add(addrLoc(p.config, d))
-        pl.add(~");$n")
+        pl.add(");\n")
         line(p, cpsStmts, pl)
       else:
         var tmp: TLoc
         getTemp(p, typ[0], tmp, needsInit=true)
         pl.add(addrLoc(p.config, tmp))
-        pl.add(~");$n")
+        pl.add(");\n")
         line(p, cpsStmts, pl)
         genAssignment(p, d, tmp, {}) # no need for deep copying
       if canRaise: raiseExit(p)
     else:
-      pl.add(~")")
+      pl.add(")")
       if p.module.compileToCpp:
         if lfSingleUse in d.flags:
           # do not generate spurious temporaries for C++! For C we're better off
@@ -140,7 +140,7 @@ proc fixupCall(p: BProc, le, ri: PNode, d: var TLoc,
         if canRaise: raiseExit(p)
         genAssignment(p, d, tmp, {})
   else:
-    pl.add(~");$n")
+    pl.add(");\n")
     line(p, cpsStmts, pl)
     if canRaise: raiseExit(p)
 
@@ -173,8 +173,10 @@ proc genOpenArraySlice(p: BProc; q: PNode; formalType, destType: PType): (Rope,
       result = ("($3*)(($1)+($2))" % [rdLoc(a), rdLoc(b), dest],
                 lengthExpr)
     else:
+      var lit = newRopeAppender()
+      intLiteral(first, lit)
       result = ("($4*)($1)+(($2)-($3))" %
-        [rdLoc(a), rdLoc(b), intLiteral(first), dest],
+        [rdLoc(a), rdLoc(b), lit, dest],
         lengthExpr)
   of tyOpenArray, tyVarargs:
     if reifiedOpenArray(q[1]):
@@ -200,7 +202,7 @@ proc genOpenArraySlice(p: BProc; q: PNode; formalType, destType: PType): (Rope,
   else:
     internalError(p.config, "openArrayLoc: " & typeToString(a.t))
 
-proc openArrayLoc(p: BProc, formalType: PType, n: PNode): Rope =
+proc openArrayLoc(p: BProc, formalType: PType, n: PNode; result: var Rope) =
   var q = skipConv(n)
   var skipped = false
   while q.kind == nkStmtListExpr and q.len > 0:
@@ -215,7 +217,7 @@ proc openArrayLoc(p: BProc, formalType: PType, n: PNode): Rope =
           genStmts(p, q[i])
         q = q.lastSon
     let (x, y) = genOpenArraySlice(p, q, formalType, n.typ[0])
-    result = x & ", " & y
+    result.add x & ", " & y
   else:
     var a: TLoc
     initLocExpr(p, if n.kind == nkHiddenStdConv: n[1] else: n, a)
@@ -223,11 +225,11 @@ proc openArrayLoc(p: BProc, formalType: PType, n: PNode): Rope =
     of tyOpenArray, tyVarargs:
       if reifiedOpenArray(n):
         if a.t.kind in {tyVar, tyLent}:
-          result = "$1->Field0, $1->Field1" % [rdLoc(a)]
+          result.add "$1->Field0, $1->Field1" % [rdLoc(a)]
         else:
-          result = "$1.Field0, $1.Field1" % [rdLoc(a)]
+          result.add "$1.Field0, $1.Field1" % [rdLoc(a)]
       else:
-        result = "$1, $1Len_0" % [rdLoc(a)]
+        result.add "$1, $1Len_0" % [rdLoc(a)]
     of tyString, tySequence:
       let ntyp = skipTypes(n.typ, abstractInst)
       if formalType.skipTypes(abstractInst).kind in {tyVar} and ntyp.kind == tyString and
@@ -236,19 +238,19 @@ proc openArrayLoc(p: BProc, formalType: PType, n: PNode): Rope =
       if ntyp.kind in {tyVar} and not compileToCpp(p.module):
         var t: TLoc
         t.r = "(*$1)" % [a.rdLoc]
-        result = "(*$1)$3, $2" % [a.rdLoc, lenExpr(p, t), dataField(p)]
+        result.add "(*$1)$3, $2" % [a.rdLoc, lenExpr(p, t), dataField(p)]
       else:
-        result = "$1$3, $2" % [a.rdLoc, lenExpr(p, a), dataField(p)]
+        result.add "$1$3, $2" % [a.rdLoc, lenExpr(p, a), dataField(p)]
     of tyArray:
-      result = "$1, $2" % [rdLoc(a), rope(lengthOrd(p.config, a.t))]
+      result.add "$1, $2" % [rdLoc(a), rope(lengthOrd(p.config, a.t))]
     of tyPtr, tyRef:
       case lastSon(a.t).kind
       of tyString, tySequence:
         var t: TLoc
         t.r = "(*$1)" % [a.rdLoc]
-        result = "(*$1)$3, $2" % [a.rdLoc, lenExpr(p, t), dataField(p)]
+        result.add "(*$1)$3, $2" % [a.rdLoc, lenExpr(p, t), dataField(p)]
       of tyArray:
-        result = "$1, $2" % [rdLoc(a), rope(lengthOrd(p.config, lastSon(a.t)))]
+        result.add "$1, $2" % [rdLoc(a), rope(lengthOrd(p.config, lastSon(a.t)))]
       else:
         internalError(p.config, "openArrayLoc: " & typeToString(a.t))
     else: internalError(p.config, "openArrayLoc: " & typeToString(a.t))
@@ -268,24 +270,24 @@ proc literalsNeedsTmp(p: BProc, a: TLoc): TLoc =
   getTemp(p, a.lode.typ, result, needsInit=false)
   genAssignment(p, result, a, {})
 
-proc genArgStringToCString(p: BProc, n: PNode, needsTmp: bool): Rope {.inline.} =
+proc genArgStringToCString(p: BProc, n: PNode; result: var Rope; needsTmp: bool) {.inline.} =
   var a: TLoc
   initLocExpr(p, n[0], a)
-  ropecg(p.module, "#nimToCStringConv($1)", [withTmpIfNeeded(p, a, needsTmp).rdLoc])
+  appcg(p.module, result, "#nimToCStringConv($1)", [withTmpIfNeeded(p, a, needsTmp).rdLoc])
 
-proc genArg(p: BProc, n: PNode, param: PSym; call: PNode, needsTmp = false): Rope =
+proc genArg(p: BProc, n: PNode, param: PSym; call: PNode; result: var Rope; needsTmp = false) =
   var a: TLoc
   if n.kind == nkStringToCString:
-    result = genArgStringToCString(p, n, needsTmp)
+    genArgStringToCString(p, n, result, needsTmp)
   elif skipTypes(param.typ, abstractVar).kind in {tyOpenArray, tyVarargs}:
     var n = if n.kind != nkHiddenAddr: n else: n[0]
-    result = openArrayLoc(p, param.typ, n)
+    openArrayLoc(p, param.typ, n, result)
   elif ccgIntroducedPtr(p.config, param, call[0].typ[0]):
     initLocExpr(p, n, a)
     if n.kind in {nkCharLit..nkNilLit}:
-      result = addrLoc(p.config, literalsNeedsTmp(p, a))
+      addAddrLoc(p.config, literalsNeedsTmp(p, a), result)
     else:
-      result = addrLoc(p.config, withTmpIfNeeded(p, a, needsTmp))
+      addAddrLoc(p.config, withTmpIfNeeded(p, a, needsTmp), result)
   elif p.module.compileToCpp and param.typ.kind in {tyVar} and
       n.kind == nkHiddenAddr:
     initLocExprSingleUse(p, n[0], a)
@@ -295,21 +297,21 @@ proc genArg(p: BProc, n: PNode, param: PSym; call: PNode, needsTmp = false): Rop
     if callee.kind == nkSym and
         {sfImportc, sfInfixCall, sfCompilerProc} * callee.sym.flags == {sfImportc} and
         {lfHeader, lfNoDecl} * callee.sym.loc.flags != {}:
-      result = addrLoc(p.config, a)
+      addAddrLoc(p.config, a, result)
     else:
-      result = rdLoc(a)
+      addRdLoc(a, result)
   else:
     initLocExprSingleUse(p, n, a)
-    result = rdLoc(withTmpIfNeeded(p, a, needsTmp))
+    addRdLoc(withTmpIfNeeded(p, a, needsTmp), result)
   #assert result != nil
 
-proc genArgNoParam(p: BProc, n: PNode, needsTmp = false): Rope =
+proc genArgNoParam(p: BProc, n: PNode; result: var Rope; needsTmp = false) =
   var a: TLoc
   if n.kind == nkStringToCString:
-    result = genArgStringToCString(p, n, needsTmp)
+    genArgStringToCString(p, n, result, needsTmp)
   else:
     initLocExprSingleUse(p, n, a)
-    result = rdLoc(withTmpIfNeeded(p, a, needsTmp))
+    addRdLoc(withTmpIfNeeded(p, a, needsTmp), result)
 
 from dfa import aliases, AliasKind
 
@@ -365,7 +367,7 @@ proc getPotentialReads(n: PNode; result: var seq[PNode]) =
     for s in n:
       getPotentialReads(s, result)
 
-proc genParams(p: BProc, ri: PNode, typ: PType): Rope =
+proc genParams(p: BProc, ri: PNode, typ: PType; result: var Rope) =
   # We must generate temporaries in cases like #14396
   # to keep the strict Left-To-Right evaluation
   var needTmp = newSeq[bool](ri.len - 1)
@@ -385,16 +387,21 @@ proc genParams(p: BProc, ri: PNode, typ: PType): Rope =
       # Optimization: don't use a temp, if we would only take the address anyway
       needTmp[i - 1] = false
 
+  var oldLen = result.len
   for i in 1..<ri.len:
     if i < typ.len:
       assert(typ.n[i].kind == nkSym)
       let paramType = typ.n[i]
       if not paramType.typ.isCompileTimeOnly:
-        if result != nil: result.add(~", ")
-        result.add(genArg(p, ri[i], paramType.sym, ri, needTmp[i-1]))
+        if oldLen != result.len:
+          result.add(", ")
+          oldLen = result.len
+        genArg(p, ri[i], paramType.sym, ri, result, needTmp[i-1])
     else:
-      if result != nil: result.add(~", ")
-      result.add(genArgNoParam(p, ri[i], needTmp[i-1]))
+      if oldLen != result.len:
+        result.add(", ")
+        oldLen = result.len
+      genArgNoParam(p, ri[i], result, needTmp[i-1])
 
 proc addActualSuffixForHCR(res: var Rope, module: PSym, sym: PSym) =
   if sym.flags * {sfImportc, sfNonReloadable} == {} and sym.loc.k == locProc and
@@ -410,7 +417,8 @@ proc genPrefixCall(p: BProc, le, ri: PNode, d: var TLoc) =
   assert(typ.kind == tyProc)
   assert(typ.len == typ.n.len)
 
-  var params = genParams(p, ri, typ)
+  var params = newRopeAppender()
+  genParams(p, ri, typ, params)
 
   var callee = rdLoc(op)
   if p.hcrOn and ri[0].kind == nkSym:
@@ -420,7 +428,7 @@ proc genPrefixCall(p: BProc, le, ri: PNode, d: var TLoc) =
 proc genClosureCall(p: BProc, le, ri: PNode, d: var TLoc) =
 
   proc addComma(r: Rope): Rope =
-    if r == nil: r else: r & ~", "
+    if r.len == 0: r else: r & ", "
 
   const PatProc = "$1.ClE_0? $1.ClP_0($3$1.ClE_0):(($4)($1.ClP_0))($2)"
   const PatIter = "$1.ClP_0($3$1.ClE_0)" # we know the env exists
@@ -433,7 +441,8 @@ proc genClosureCall(p: BProc, le, ri: PNode, d: var TLoc) =
   assert(typ.kind == tyProc)
   assert(typ.len == typ.n.len)
 
-  var pl = genParams(p, ri, typ)
+  var pl = newRopeAppender()
+  genParams(p, ri, typ, pl)
 
   template genCallPattern {.dirty.} =
     if tfIterator in typ.flags:
@@ -445,7 +454,7 @@ proc genClosureCall(p: BProc, le, ri: PNode, d: var TLoc) =
   let canRaise = p.config.exc == excGoto and canRaiseDisp(p, ri[0])
   if typ[0] != nil:
     if isInvalidReturnType(p.config, typ):
-      if ri.len > 1: pl.add(~", ")
+      if ri.len > 1: pl.add(", ")
       # beware of 'result = p(result)'. We may need to allocate a temporary:
       if d.k in {locTemp, locNone} or not preventNrvo(p, d.lode, le, ri):
         # Great, we can use 'd':
@@ -491,24 +500,30 @@ proc genClosureCall(p: BProc, le, ri: PNode, d: var TLoc) =
     genCallPattern()
     if canRaise: raiseExit(p)
 
-proc genOtherArg(p: BProc; ri: PNode; i: int; typ: PType): Rope =
+proc genOtherArg(p: BProc; ri: PNode; i: int; typ: PType; result: var Rope;
+                 argsCounter: var int) =
   if i < typ.len:
     # 'var T' is 'T&' in C++. This means we ignore the request of
     # any nkHiddenAddr when it's a 'var T'.
     let paramType = typ.n[i]
     assert(paramType.kind == nkSym)
     if paramType.typ.isCompileTimeOnly:
-      result = nil
+      discard
     elif typ[i].kind in {tyVar} and ri[i].kind == nkHiddenAddr:
-      result = genArgNoParam(p, ri[i][0])
+      if argsCounter > 0: result.add ", "
+      genArgNoParam(p, ri[i][0], result)
+      inc argsCounter
     else:
-      result = genArgNoParam(p, ri[i]) #, typ.n[i].sym)
+      if argsCounter > 0: result.add ", "
+      genArgNoParam(p, ri[i], result) #, typ.n[i].sym)
+      inc argsCounter
   else:
     if tfVarargs notin typ.flags:
       localError(p.config, ri.info, "wrong argument count")
-      result = nil
     else:
-      result = genArgNoParam(p, ri[i])
+      if argsCounter > 0: result.add ", "
+      genArgNoParam(p, ri[i], result)
+      inc argsCounter
 
 discard """
 Dot call syntax in C++
@@ -565,7 +580,7 @@ proc skipAddrDeref(node: PNode): PNode =
   else:
     result = node
 
-proc genThisArg(p: BProc; ri: PNode; i: int; typ: PType): Rope =
+proc genThisArg(p: BProc; ri: PNode; i: int; typ: PType; result: var Rope) =
   # for better or worse c2nim translates the 'this' argument to a 'var T'.
   # However manual wrappers may also use 'ptr T'. In any case we support both
   # for convenience.
@@ -579,75 +594,72 @@ proc genThisArg(p: BProc; ri: PNode; i: int; typ: PType): Rope =
   if t.kind in {tyVar}:
     let x = if ri.kind == nkHiddenAddr: ri[0] else: ri
     if x.typ.kind == tyPtr:
-      result = genArgNoParam(p, x)
+      genArgNoParam(p, x, result)
       result.add("->")
     elif x.kind in {nkHiddenDeref, nkDerefExpr} and x[0].typ.kind == tyPtr:
-      result = genArgNoParam(p, x[0])
+      genArgNoParam(p, x[0], result)
       result.add("->")
     else:
-      result = genArgNoParam(p, x)
+      genArgNoParam(p, x, result)
       result.add(".")
   elif t.kind == tyPtr:
     if ri.kind in {nkAddr, nkHiddenAddr}:
-      result = genArgNoParam(p, ri[0])
+      genArgNoParam(p, ri[0], result)
       result.add(".")
     else:
-      result = genArgNoParam(p, ri)
+      genArgNoParam(p, ri, result)
       result.add("->")
   else:
     ri = skipAddrDeref(ri)
     if ri.kind in {nkAddr, nkHiddenAddr}: ri = ri[0]
-    result = genArgNoParam(p, ri) #, typ.n[i].sym)
+    genArgNoParam(p, ri, result) #, typ.n[i].sym)
     result.add(".")
 
-proc genPatternCall(p: BProc; ri: PNode; pat: string; typ: PType): Rope =
+proc genPatternCall(p: BProc; ri: PNode; pat: string; typ: PType; result: var Rope) =
   var i = 0
   var j = 1
   while i < pat.len:
     case pat[i]
     of '@':
-      var first = true
+      var argsCounter = 0
       for k in j..<ri.len:
-        let arg = genOtherArg(p, ri, k, typ)
-        if arg.len > 0:
-          if not first:
-            result.add(~", ")
-          first = false
-          result.add arg
+        genOtherArg(p, ri, k, typ, result, argsCounter)
       inc i
     of '#':
       if i+1 < pat.len and pat[i+1] in {'+', '@'}:
         let ri = ri[j]
         if ri.kind in nkCallKinds:
           let typ = skipTypes(ri[0].typ, abstractInst)
-          if pat[i+1] == '+': result.add genArgNoParam(p, ri[0])
-          result.add(~"(")
+          if pat[i+1] == '+': genArgNoParam(p, ri[0], result)
+          result.add("(")
           if 1 < ri.len:
-            result.add genOtherArg(p, ri, 1, typ)
+            var argsCounterB = 0
+            genOtherArg(p, ri, 1, typ, result, argsCounterB)
           for k in j+1..<ri.len:
-            result.add(~", ")
-            result.add genOtherArg(p, ri, k, typ)
-          result.add(~")")
+            var argsCounterB = 0
+            genOtherArg(p, ri, k, typ, result, argsCounterB)
+          result.add(")")
         else:
           localError(p.config, ri.info, "call expression expected for C++ pattern")
         inc i
       elif i+1 < pat.len and pat[i+1] == '.':
-        result.add genThisArg(p, ri, j, typ)
+        genThisArg(p, ri, j, typ, result)
         inc i
       elif i+1 < pat.len and pat[i+1] == '[':
         var arg = ri[j].skipAddrDeref
         while arg.kind in {nkAddr, nkHiddenAddr, nkObjDownConv}: arg = arg[0]
-        result.add genArgNoParam(p, arg)
+        genArgNoParam(p, arg, result)
         #result.add debugTree(arg, 0, 10)
       else:
-        result.add genOtherArg(p, ri, j, typ)
+        var argsCounter = 0
+        genOtherArg(p, ri, j, typ, result, argsCounter)
       inc j
       inc i
     of '\'':
       var idx, stars: int
       if scanCppGenericSlot(pat, i, idx, stars):
         var t = resolveStarsInCppType(typ, idx, stars)
-        if t == nil: result.add(~"void")
+        if t == nil: result.add("void")
         else: result.add(getTypeDesc(p.module, t))
     else:
       let start = i
@@ -665,10 +677,11 @@ proc genInfixCall(p: BProc, le, ri: PNode, d: var TLoc) =
   assert(typ.kind == tyProc)
   assert(typ.len == typ.n.len)
   # don't call '$' here for efficiency:
-  let pat = ri[0].sym.loc.r.data
+  let pat = $ri[0].sym.loc.r
   internalAssert p.config, pat.len > 0
   if pat.contains({'#', '(', '@', '\''}):
-    var pl = genPatternCall(p, ri, pat, typ)
+    var pl = newRopeAppender()
+    genPatternCall(p, ri, pat, typ, pl)
     # simpler version of 'fixupCall' that works with the pl+params combination:
     var typ = skipTypes(ri[0].typ, abstractInst)
     if typ[0] != nil:
@@ -687,80 +700,79 @@ proc genInfixCall(p: BProc, le, ri: PNode, d: var TLoc) =
         list.r = pl
         genAssignment(p, d, list, {}) # no need for deep copying
     else:
-      pl.add(~";$n")
+      pl.add(";\n")
       line(p, cpsStmts, pl)
   else:
-    var pl: Rope = nil
-    #var param = typ.n[1].sym
+    var pl = newRopeAppender()
+    var argsCounter = 0
     if 1 < ri.len:
-      pl.add(genThisArg(p, ri, 1, typ))
+      genThisArg(p, ri, 1, typ, pl)
     pl.add(op.r)
-    var params: Rope
+    var params = newRopeAppender()
     for i in 2..<ri.len:
-      if params != nil: params.add(~", ")
       assert(typ.len == typ.n.len)
-      params.add(genOtherArg(p, ri, i, typ))
+      genOtherArg(p, ri, i, typ, params, argsCounter)
     fixupCall(p, le, ri, d, pl, params)
 
 proc genNamedParamCall(p: BProc, ri: PNode, d: var TLoc) =
   # generates a crappy ObjC call
   var op: TLoc
   initLocExpr(p, ri[0], op)
-  var pl = ~"["
+  var pl = "["
   # getUniqueType() is too expensive here:
   var typ = skipTypes(ri[0].typ, abstractInst)
   assert(typ.kind == tyProc)
   assert(typ.len == typ.n.len)
 
   # don't call '$' here for efficiency:
-  let pat = ri[0].sym.loc.r.data
+  let pat = $ri[0].sym.loc.r
   internalAssert p.config, pat.len > 0
   var start = 3
   if ' ' in pat:
     start = 1
     pl.add(op.r)
     if ri.len > 1:
-      pl.add(~": ")
-      pl.add(genArg(p, ri[1], typ.n[1].sym, ri))
+      pl.add(": ")
+      genArg(p, ri[1], typ.n[1].sym, ri, pl)
       start = 2
   else:
     if ri.len > 1:
-      pl.add(genArg(p, ri[1], typ.n[1].sym, ri))
-      pl.add(~" ")
+      genArg(p, ri[1], typ.n[1].sym, ri, pl)
+      pl.add(" ")
     pl.add(op.r)
     if ri.len > 2:
-      pl.add(~": ")
-      pl.add(genArg(p, ri[2], typ.n[2].sym, ri))
+      pl.add(": ")
+      genArg(p, ri[2], typ.n[2].sym, ri, pl)
   for i in start..<ri.len:
     assert(typ.len == typ.n.len)
     if i >= typ.len:
       internalError(p.config, ri.info, "varargs for objective C method?")
     assert(typ.n[i].kind == nkSym)
     var param = typ.n[i].sym
-    pl.add(~" ")
+    pl.add(" ")
     pl.add(param.name.s)
-    pl.add(~": ")
-    pl.add(genArg(p, ri[i], param, ri))
+    pl.add(": ")
+    genArg(p, ri[i], param, ri, pl)
   if typ[0] != nil:
     if isInvalidReturnType(p.config, typ):
-      if ri.len > 1: pl.add(~" ")
+      if ri.len > 1: pl.add(" ")
       # beware of 'result = p(result)'. We always allocate a temporary:
       if d.k in {locTemp, locNone}:
         # We already got a temp. Great, special case it:
         if d.k == locNone: getTemp(p, typ[0], d, needsInit=true)
-        pl.add(~"Result: ")
+        pl.add("Result: ")
         pl.add(addrLoc(p.config, d))
-        pl.add(~"];$n")
+        pl.add("];\n")
         line(p, cpsStmts, pl)
       else:
         var tmp: TLoc
         getTemp(p, typ[0], tmp, needsInit=true)
         pl.add(addrLoc(p.config, tmp))
-        pl.add(~"];$n")
+        pl.add("];\n")
         line(p, cpsStmts, pl)
         genAssignment(p, d, tmp, {}) # no need for deep copying
     else:
-      pl.add(~"]")
+      pl.add("]")
       if d.k == locNone: getTemp(p, typ[0], d)
       assert(d.t != nil)        # generate an assignment to d:
       var list: TLoc
@@ -768,7 +780,7 @@ proc genNamedParamCall(p: BProc, ri: PNode, d: var TLoc) =
       list.r = pl
       genAssignment(p, d, list, {}) # no need for deep copying
   else:
-    pl.add(~"];$n")
+    pl.add("];\n")
     line(p, cpsStmts, pl)
 
 proc notYetAlive(n: PNode): bool {.inline.} =
diff --git a/compiler/ccgexprs.nim b/compiler/ccgexprs.nim
index 99e43056d9776..8395eea8a7402 100644
--- a/compiler/ccgexprs.nim
+++ b/compiler/ccgexprs.nim
@@ -18,31 +18,31 @@ proc getNullValueAuxT(p: BProc; orig, t: PType; obj, constOrNil: PNode,
 
 # -------------------------- constant expressions ------------------------
 
-proc rdSetElemLoc(conf: ConfigRef; a: TLoc, typ: PType): Rope
+proc rdSetElemLoc(conf: ConfigRef; a: TLoc, typ: PType; result: var Rope)
 
-proc int64Literal(i: BiggestInt): Rope =
+proc int64Literal(i: BiggestInt; result: var Rope) =
   if i > low(int64):
-    result = "IL64($1)" % [rope(i)]
+    result.add "IL64($1)" % [rope(i)]
   else:
-    result = ~"(IL64(-9223372036854775807) - IL64(1))"
+    result.add "(IL64(-9223372036854775807) - IL64(1))"
 
-proc uint64Literal(i: uint64): Rope = rope($i & "ULL")
+proc uint64Literal(i: uint64; result: var Rope) = result.add rope($i & "ULL")
 
-proc intLiteral(i: BiggestInt): Rope =
+proc intLiteral(i: BiggestInt; result: var Rope) =
   if i > low(int32) and i <= high(int32):
-    result = rope(i)
+    result.add rope(i)
   elif i == low(int32):
     # Nim has the same bug for the same reasons :-)
-    result = ~"(-2147483647 -1)"
+    result.add "(-2147483647 -1)"
   elif i > low(int64):
-    result = "IL64($1)" % [rope(i)]
+    result.add "IL64($1)" % [rope(i)]
   else:
-    result = ~"(IL64(-9223372036854775807) - IL64(1))"
+    result.add "(IL64(-9223372036854775807) - IL64(1))"
 
-proc intLiteral(i: Int128): Rope =
-  intLiteral(toInt64(i))
+proc intLiteral(i: Int128; result: var Rope) =
+  intLiteral(toInt64(i), result)
 
-proc genLiteral(p: BProc, n: PNode, ty: PType): Rope =
+proc genLiteral(p: BProc, n: PNode, ty: PType; result: var Rope) =
   case n.kind
   of nkCharLit..nkUInt64Lit:
     var k: TTypeKind
@@ -56,65 +56,68 @@ proc genLiteral(p: BProc, n: PNode, ty: PType): Rope =
       else: k = tyNil # don't go into the case variant that uses 'ty'
     case k
     of tyChar, tyNil:
-      result = intLiteral(n.intVal)
+      intLiteral(n.intVal, result)
     of tyBool:
-      if n.intVal != 0: result = ~"NIM_TRUE"
-      else: result = ~"NIM_FALSE"
-    of tyInt64: result = int64Literal(n.intVal)
-    of tyUInt64: result = uint64Literal(uint64(n.intVal))
-    else:
-      result = "(($1) $2)" % [getTypeDesc(p.module,
-          ty), intLiteral(n.intVal)]
+      if n.intVal != 0: result.add "NIM_TRUE"
+      else: result.add "NIM_FALSE"
+    of tyInt64: int64Literal(n.intVal, result)
+    of tyUInt64: uint64Literal(uint64(n.intVal), result)
+    else:
+      result.add "(("
+      result.add getTypeDesc(p.module, ty)
+      result.add ")"
+      intLiteral(n.intVal, result)
+      result.add ")"
   of nkNilLit:
     let k = if ty == nil: tyPointer else: skipTypes(ty, abstractVarRange).kind
     if k == tyProc and skipTypes(ty, abstractVarRange).callConv == ccClosure:
       let id = nodeTableTestOrSet(p.module.dataCache, n, p.module.labels)
-      result = p.module.tmpBase & rope(id)
+      let tmpName = p.module.tmpBase & rope(id)
       if id == p.module.labels:
         # not found in cache:
         inc(p.module.labels)
-        p.module.s[cfsData].addf(
+        p.module.s[cfsStrData].addf(
              "static NIM_CONST $1 $2 = {NIM_NIL,NIM_NIL};$n",
-             [getTypeDesc(p.module, ty), result])
+             [getTypeDesc(p.module, ty), tmpName])
+      result.add tmpName
     elif k in {tyPointer, tyNil, tyProc}:
-      result = rope("NIM_NIL")
+      result.add rope("NIM_NIL")
     else:
-      result = "(($1) NIM_NIL)" % [getTypeDesc(p.module, ty)]
+      result.add "(($1) NIM_NIL)" % [getTypeDesc(p.module, ty)]
   of nkStrLit..nkTripleStrLit:
     let k = if ty == nil: tyString
             else: skipTypes(ty, abstractVarRange + {tyStatic, tyUserTypeClass, tyUserTypeClassInst}).kind
     case k
     of tyNil:
-      result = genNilStringLiteral(p.module, n.info)
+      genNilStringLiteral(p.module, n.info, result)
     of tyString:
       # with the new semantics for not 'nil' strings, we can map "" to nil and
       # save tons of allocations:
       if n.strVal.len == 0 and optSeqDestructors notin p.config.globalOptions:
-        result = genNilStringLiteral(p.module, n.info)
+        genNilStringLiteral(p.module, n.info, result)
       else:
-        result = genStringLiteral(p.module, n)
+        genStringLiteral(p.module, n, result)
     else:
-      result = makeCString(n.strVal)
+      result.add makeCString(n.strVal)
   of nkFloatLit, nkFloat64Lit:
     if ty.kind == tyFloat32:
-      result = rope(n.floatVal.float32.toStrMaxPrecision)
+      result.add rope(n.floatVal.float32.toStrMaxPrecision)
     else:
-      result = rope(n.floatVal.toStrMaxPrecision)
+      result.add rope(n.floatVal.toStrMaxPrecision)
   of nkFloat32Lit:
-    result = rope(n.floatVal.float32.toStrMaxPrecision)
+    result.add rope(n.floatVal.float32.toStrMaxPrecision)
   else:
     internalError(p.config, n.info, "genLiteral(" & $n.kind & ')')
-    result = nil
 
-proc genLiteral(p: BProc, n: PNode): Rope =
-  result = genLiteral(p, n, n.typ)
+proc genLiteral(p: BProc, n: PNode; result: var Rope) =
+  genLiteral(p, n, n.typ, result)
 
 proc bitSetToWord(s: TBitSet, size: int): BiggestUInt =
   result = 0
   for j in 0..<size:
     if j < s.len: result = result or (BiggestUInt(s[j]) shl (j * 8))
 
-proc genRawSetData(cs: TBitSet, size: int): Rope =
+proc genRawSetData(cs: TBitSet, size: int; result: var Rope) =
   if size > 8:
     var res = "{\n"
     for i in 0..<size:
@@ -130,23 +133,26 @@ proc genRawSetData(cs: TBitSet, size: int): Rope =
       else:
         res.add "}\n"
 
-    result = rope(res)
+    result.add rope(res)
   else:
-    result = intLiteral(cast[BiggestInt](bitSetToWord(cs, size)))
+    intLiteral(cast[BiggestInt](bitSetToWord(cs, size)), result)
 
-proc genSetNode(p: BProc, n: PNode): Rope =
+proc genSetNode(p: BProc, n: PNode; result: var Rope) =
   var size = int(getSize(p.config, n.typ))
   let cs = toBitSet(p.config, n)
   if size > 8:
     let id = nodeTableTestOrSet(p.module.dataCache, n, p.module.labels)
-    result = p.module.tmpBase & rope(id)
+    let tmpName = p.module.tmpBase & rope(id)
     if id == p.module.labels:
       # not found in cache:
       inc(p.module.labels)
-      p.module.s[cfsData].addf("static NIM_CONST $1 $2 = $3;$n",
-           [getTypeDesc(p.module, n.typ), result, genRawSetData(cs, size)])
+      p.module.s[cfsStrData].addf("static NIM_CONST $1 $2 = ",
+           [getTypeDesc(p.module, n.typ), tmpName])
+      genRawSetData(cs, size, p.module.s[cfsStrData])
+      p.module.s[cfsStrData].addf(";$n", [])
+    result.add tmpName
   else:
-    result = genRawSetData(cs, size)
+    genRawSetData(cs, size, result)
 
 proc getStorageLoc(n: PNode): TStorageLoc =
   ## deadcode
@@ -214,7 +220,7 @@ proc asgnComplexity(n: PNode): int =
     else: discard
 
 proc optAsgnLoc(a: TLoc, t: PType, field: Rope): TLoc =
-  assert field != nil
+  assert field != ""
   result.k = locField
   result.storage = a.storage
   result.lode = lodeTyp t
@@ -248,7 +254,7 @@ proc genOptAsgnObject(p: BProc, dest, src: TLoc, flags: TAssignmentFlags,
   case t.kind
   of nkSym:
     let field = t.sym
-    if field.loc.r == nil: fillObjectFields(p.module, typ)
+    if field.loc.r == "": fillObjectFields(p.module, typ)
     genAssignment(p, optAsgnLoc(dest, field.typ, field.loc.r),
                      optAsgnLoc(src, field.typ, field.loc.r), newflags)
   of nkRecList:
@@ -549,12 +555,21 @@ template binaryArithOverflowRaw(p: BProc, t: PType, a, b: TLoc;
                 else: getTypeDesc(p.module, t)
   var result = getTempName(p.module)
   linefmt(p, cpsLocals, "$1 $2;$n", [storage, result])
-  lineCg(p, cpsStmts, "if (#$2($3, $4, &$1)) { #raiseOverflow(); $5};$n",
-      [result, cpname, rdCharLoc(a), rdCharLoc(b), raiseInstr(p)])
+  lineCg(p, cpsStmts, "if (#$2($3, $4, &$1)) { #raiseOverflow(); ",
+      [result, cpname, rdCharLoc(a), rdCharLoc(b)])
+  raiseInstr(p, p.s(cpsStmts))
+  linefmt p, cpsStmts, "};$n", []
+
   if size < p.config.target.intSize or t.kind in {tyRange, tyEnum}:
-    linefmt(p, cpsStmts, "if ($1 < $2 || $1 > $3){ #raiseOverflow(); $4}$n",
-            [result, intLiteral(firstOrd(p.config, t)), intLiteral(lastOrd(p.config, t)),
-            raiseInstr(p)])
+    var first = newRopeAppender()
+    intLiteral(firstOrd(p.config, t), first)
+    var last = newRopeAppender()
+    intLiteral(lastOrd(p.config, t), last)
+    linefmt(p, cpsStmts, "if ($1 < $2 || $1 > $3){ #raiseOverflow(); ",
+            [result, first, last])
+    raiseInstr(p, p.s(cpsStmts))
+    linefmt p, cpsStmts, "}$n", []
+
   result
 
 proc binaryArithOverflow(p: BProc, e: PNode, d: var TLoc, m: TMagic) =
@@ -592,8 +607,9 @@ proc binaryArithOverflow(p: BProc, e: PNode, d: var TLoc, m: TMagic) =
       if e[2].kind in {nkIntLit..nkInt64Lit}:
         needsOverflowCheck = e[2].intVal == -1
       if canBeZero:
-        linefmt(p, cpsStmts, "if ($1 == 0){ #raiseDivByZero(); $2}$n",
-                [rdLoc(b), raiseInstr(p)])
+        linefmt(p, cpsStmts, "if ($1 == 0){ #raiseDivByZero(); ", [rdLoc(b)])
+        raiseInstr(p, p.s(cpsStmts))
+        linefmt(p, cpsStmts, "}$n", [])
     if needsOverflowCheck:
       let res = binaryArithOverflowRaw(p, t, a, b,
         if t.kind == tyInt64: prc64[m] else: prc[m])
@@ -610,8 +626,13 @@ proc unaryArithOverflow(p: BProc, e: PNode, d: var TLoc, m: TMagic) =
   initLocExpr(p, e[1], a)
   t = skipTypes(e.typ, abstractRange)
   if optOverflowCheck in p.options:
-    linefmt(p, cpsStmts, "if ($1 == $2){ #raiseOverflow(); $3}$n",
-            [rdLoc(a), intLiteral(firstOrd(p.config, t)), raiseInstr(p)])
+    var first = newRopeAppender()
+    intLiteral(firstOrd(p.config, t), first)
+    linefmt(p, cpsStmts, "if ($1 == $2){ #raiseOverflow(); ",
+            [rdLoc(a), first])
+    raiseInstr(p, p.s(cpsStmts))
+    linefmt p, cpsStmts, "}$n", []
+
   case m
   of mUnaryMinusI:
     putIntoDest(p, d, e, "((NI$2)-($1))" % [rdLoc(a), rope(getSize(p.config, t) * 8)])
@@ -850,7 +871,7 @@ proc genTupleElem(p: BProc, e: PNode, d: var TLoc) =
 proc lookupFieldAgain(p: BProc, ty: PType; field: PSym; r: var Rope;
                       resTyp: ptr PType = nil): PSym =
   var ty = ty
-  assert r != nil
+  assert r != ""
   while ty != nil:
     ty = ty.skipTypes(skipPtrs)
     assert(ty.kind in {tyTuple, tyObject})
@@ -871,15 +892,18 @@ proc genRecordField(p: BProc, e: PNode, d: var TLoc) =
   if ty.kind == tyTuple:
     # we found a unique tuple type which lacks field information
     # so we use Field$i
-    r.addf(".Field$1", [rope(f.position)])
+    r.add ".Field"
+    r.add rope(f.position)
     putIntoDest(p, d, e, r, a.storage)
   else:
     var rtyp: PType
     let field = lookupFieldAgain(p, ty, f, r, addr rtyp)
-    if field.loc.r == nil and rtyp != nil: fillObjectFields(p.module, rtyp)
-    if field.loc.r == nil: internalError(p.config, e.info, "genRecordField 3 " & typeToString(ty))
-    r.addf(".$1", [field.loc.r])
+    if field.loc.r == "" and rtyp != nil: fillObjectFields(p.module, rtyp)
+    if field.loc.r == "": internalError(p.config, e.info, "genRecordField 3 " & typeToString(ty))
+    r.add "."
+    r.add field.loc.r
     putIntoDest(p, d, e, r, a.storage)
+  r.freeze
 
 proc genInExprAux(p: BProc, e: PNode, a, b, d: var TLoc)
 
@@ -896,7 +920,8 @@ proc genFieldCheck(p: BProc, e: PNode, obj: Rope, field: PSym) =
     initLoc(test, locNone, it, OnStack)
     initLocExpr(p, it[1], u)
     initLoc(v, locExpr, disc, OnUnknown)
-    v.r = obj
+    v.r = newRopeAppender()
+    v.r.add obj
     v.r.add(".")
     v.r.add(disc.sym.loc.r)
     genInExprAux(p, it, u, v, test)
@@ -909,33 +934,40 @@ proc genFieldCheck(p: BProc, e: PNode, obj: Rope, field: PSym) =
       # passing around `TLineInfo` + the set of files in the project.
       msg.add toFileLineCol(p.config, e.info) & " "
     msg.add genFieldDefect(p.config, field.name.s, disc.sym)
-    let strLit = genStringLiteral(p.module, newStrNode(nkStrLit, msg))
+    var strLit = newRopeAppender()
+    genStringLiteral(p.module, newStrNode(nkStrLit, msg), strLit)
 
     ## discriminant check
     template fun(code) = linefmt(p, cpsStmts, code, [rdLoc(test)])
     if op.magic == mNot: fun("if ($1) ") else: fun("if (!($1)) ")
 
     ## call raiseFieldError2 on failure
-    let discIndex = rdSetElemLoc(p.config, v, u.t)
+    var discIndex = newRopeAppender()
+    rdSetElemLoc(p.config, v, u.t, discIndex)
     if optTinyRtti in p.config.globalOptions:
       # not sure how to use `genEnumToStr` here
-      if p.config.getStdlibVersion < (1,5,1):
-        const code = "{ #raiseFieldError($1); $2} $n"
-        linefmt(p, cpsStmts, code, [strLit, raiseInstr(p)])
+      if p.config.getStdlibVersion < (1, 5, 1):
+        const code = "{ #raiseFieldError($1); "
+        linefmt(p, cpsStmts, code, [strLit])
       else:
-        const code = "{ #raiseFieldError2($1, (NI)$3); $2} $n"
-        linefmt(p, cpsStmts, code, [strLit, raiseInstr(p), discIndex])
+        const code = "{ #raiseFieldError2($1, (NI)$2); "
+        linefmt(p, cpsStmts, code, [strLit, discIndex])
+
     else:
       # complication needed for signed types
       let first = p.config.firstOrd(disc.sym.typ)
-      let firstLit = int64Literal(cast[int](first))
+      var firstLit = newRopeAppender()
+      int64Literal(cast[int](first), firstLit)
       let discName = genTypeInfo(p.config, p.module, disc.sym.typ, e.info)
       if p.config.getStdlibVersion < (1,5,1):
-        const code = "{ #raiseFieldError($1); $2} $n"
-        linefmt(p, cpsStmts, code, [strLit, raiseInstr(p)])
+        const code = "{ #raiseFieldError($1); "
+        linefmt(p, cpsStmts, code, [strLit])
       else:
-        const code = "{ #raiseFieldError2($1, #reprDiscriminant(((NI)$3) + (NI)$4, $5)); $2} $n"
-        linefmt(p, cpsStmts, code, [strLit, raiseInstr(p), discIndex, firstLit, discName])
+        const code = "{ #raiseFieldError2($1, #reprDiscriminant(((NI)$2) + (NI)$3, $4)); "
+        linefmt(p, cpsStmts, code, [strLit, discIndex, firstLit, discName])
+
+    raiseInstr(p, p.s(cpsStmts))
+    linefmt p, cpsStmts, "}$n", []
 
 proc genCheckedRecordField(p: BProc, e: PNode, d: var TLoc) =
   assert e[0].kind == nkDotExpr
@@ -946,12 +978,14 @@ proc genCheckedRecordField(p: BProc, e: PNode, d: var TLoc) =
     var r = rdLoc(a)
     let f = e[0][1].sym
     let field = lookupFieldAgain(p, ty, f, r)
-    if field.loc.r == nil: fillObjectFields(p.module, ty)
-    if field.loc.r == nil:
+    if field.loc.r == "": fillObjectFields(p.module, ty)
+    if field.loc.r == "":
       internalError(p.config, e.info, "genCheckedRecordField") # generate the checks:
     genFieldCheck(p, e, r, field)
-    r.add(ropecg(p.module, ".$1", [field.loc.r]))
+    r.add(".")
+    r.add field.loc.r
     putIntoDest(p, d, e[0], r, a.storage)
+    r.freeze
   else:
     genRecordField(p, e[0], d)
 
@@ -968,18 +1002,28 @@ proc genArrayElem(p: BProc, n, x, y: PNode, d: var TLoc) =
   initLocExpr(p, x, a)
   initLocExpr(p, y, b)
   var ty = skipTypes(a.t, abstractVarRange + abstractPtrs + tyUserTypeClasses)
-  var first = intLiteral(firstOrd(p.config, ty))
+  var first = newRopeAppender()
+  intLiteral(firstOrd(p.config, ty), first)
   # emit range check:
   if optBoundsCheck in p.options and ty.kind != tyUncheckedArray:
     if not isConstExpr(y):
       # semantic pass has already checked for const index expressions
       if firstOrd(p.config, ty) == 0 and lastOrd(p.config, ty) >= 0:
         if (firstOrd(p.config, b.t) < firstOrd(p.config, ty)) or (lastOrd(p.config, b.t) > lastOrd(p.config, ty)):
-          linefmt(p, cpsStmts, "if ((NU)($1) > (NU)($2)){ #raiseIndexError2($1, $2); $3}$n",
-                  [rdCharLoc(b), intLiteral(lastOrd(p.config, ty)), raiseInstr(p)])
+          var last = newRopeAppender()
+          intLiteral(lastOrd(p.config, ty), last)
+          linefmt(p, cpsStmts, "if ((NU)($1) > (NU)($2)){ #raiseIndexError2($1, $2); ",
+                  [rdCharLoc(b), last])
+          raiseInstr(p, p.s(cpsStmts))
+          linefmt p, cpsStmts, "}$n", []
       else:
-        linefmt(p, cpsStmts, "if ($1 < $2 || $1 > $3){ #raiseIndexError3($1, $2, $3); $4}$n",
-                [rdCharLoc(b), first, intLiteral(lastOrd(p.config, ty)), raiseInstr(p)])
+        var last = newRopeAppender()
+        intLiteral(lastOrd(p.config, ty), last)
+        linefmt(p, cpsStmts, "if ($1 < $2 || $1 > $3){ #raiseIndexError3($1, $2, $3); ",
+                [rdCharLoc(b), first, last])
+        raiseInstr(p, p.s(cpsStmts))
+        linefmt p, cpsStmts, "}$n", []
+
     else:
       let idx = getOrdValue(y)
       if idx < firstOrd(p.config, ty) or idx > lastOrd(p.config, ty):
@@ -1003,24 +1047,37 @@ proc genBoundsCheck(p: BProc; arr, a, b: TLoc) =
     if reifiedOpenArray(arr.lode):
       linefmt(p, cpsStmts,
         "if ($2-$1 != -1 && " &
-        "($1 < 0 || $1 >= $3.Field1 || $2 < 0 || $2 >= $3.Field1)){ #raiseIndexError4($1, $2, $3.Field1); $4}$n",
-        [rdLoc(a), rdLoc(b), rdLoc(arr), raiseInstr(p)])
+        "($1 < 0 || $1 >= $3.Field1 || $2 < 0 || $2 >= $3.Field1)){ #raiseIndexError4($1, $2, $3.Field1); ",
+        [rdLoc(a), rdLoc(b), rdLoc(arr)])
     else:
       linefmt(p, cpsStmts,
         "if ($2-$1 != -1 && ($1 < 0 || $1 >= $3Len_0 || $2 < 0 || $2 >= $3Len_0))" &
-        "{ #raiseIndexError4($1, $2, $3Len_0); $4}$n",
-        [rdLoc(a), rdLoc(b), rdLoc(arr), raiseInstr(p)])
+        "{ #raiseIndexError4($1, $2, $3Len_0); ",
+        [rdLoc(a), rdLoc(b), rdLoc(arr)])
+    raiseInstr(p, p.s(cpsStmts))
+    linefmt p, cpsStmts, "}$n", []
+
   of tyArray:
-    let first = intLiteral(firstOrd(p.config, ty))
+    var first = newRopeAppender()
+    intLiteral(firstOrd(p.config, ty), first)
+    var last = newRopeAppender()
+    intLiteral(lastOrd(p.config, ty), last)
     linefmt(p, cpsStmts,
       "if ($2-$1 != -1 && " &
-      "($2-$1 < -1 || $1 < $3 || $1 > $4 || $2 < $3 || $2 > $4)){ #raiseIndexError(); $5}$n",
-      [rdCharLoc(a), rdCharLoc(b), first, intLiteral(lastOrd(p.config, ty)), raiseInstr(p)])
+      "($2-$1 < -1 || $1 < $3 || $1 > $4 || $2 < $3 || $2 > $4)){ #raiseIndexError(); ",
+      [rdCharLoc(a), rdCharLoc(b), first, last])
+
+    raiseInstr(p, p.s(cpsStmts))
+    linefmt p, cpsStmts, "}$n", []
+
   of tySequence, tyString:
     linefmt(p, cpsStmts,
       "if ($2-$1 != -1 && " &
-      "($1 < 0 || $1 >= $3 || $2 < 0 || $2 >= $3)){ #raiseIndexError4($1, $2, $3); $4}$n",
-      [rdLoc(a), rdLoc(b), lenExpr(p, arr), raiseInstr(p)])
+      "($1 < 0 || $1 >= $3 || $2 < 0 || $2 >= $3)){ #raiseIndexError4($1, $2, $3); ",
+      [rdLoc(a), rdLoc(b), lenExpr(p, arr)])
+    raiseInstr(p, p.s(cpsStmts))
+    linefmt p, cpsStmts, "}$n", []
+
   else: discard
 
 proc genOpenArrayElem(p: BProc, n, x, y: PNode, d: var TLoc) =
@@ -1030,15 +1087,21 @@ proc genOpenArrayElem(p: BProc, n, x, y: PNode, d: var TLoc) =
   if not reifiedOpenArray(x):
     # emit range check:
     if optBoundsCheck in p.options:
-      linefmt(p, cpsStmts, "if ($1 < 0 || $1 >= $2Len_0){ #raiseIndexError2($1,$2Len_0-1); $3}$n",
-              [rdCharLoc(b), rdLoc(a), raiseInstr(p)]) # BUGFIX: ``>=`` and not ``>``!
+      linefmt(p, cpsStmts, "if ($1 < 0 || $1 >= $2Len_0){ #raiseIndexError2($1,$2Len_0-1); ",
+              [rdCharLoc(b), rdLoc(a)]) # BUGFIX: ``>=`` and not ``>``!
+      raiseInstr(p, p.s(cpsStmts))
+      linefmt p, cpsStmts, "}$n", []
+
     inheritLocation(d, a)
     putIntoDest(p, d, n,
                 ropecg(p.module, "$1[$2]", [rdLoc(a), rdCharLoc(b)]), a.storage)
   else:
     if optBoundsCheck in p.options:
-      linefmt(p, cpsStmts, "if ($1 < 0 || $1 >= $2.Field1){ #raiseIndexError2($1,$2.Field1-1); $3}$n",
-              [rdCharLoc(b), rdLoc(a), raiseInstr(p)]) # BUGFIX: ``>=`` and not ``>``!
+      linefmt(p, cpsStmts, "if ($1 < 0 || $1 >= $2.Field1){ #raiseIndexError2($1,$2.Field1-1); ",
+              [rdCharLoc(b), rdLoc(a)]) # BUGFIX: ``>=`` and not ``>``!
+      raiseInstr(p, p.s(cpsStmts))
+      linefmt p, cpsStmts, "}$n", []
+
     inheritLocation(d, a)
     putIntoDest(p, d, n,
                 ropecg(p.module, "$1.Field0[$2]", [rdLoc(a), rdCharLoc(b)]), a.storage)
@@ -1052,8 +1115,11 @@ proc genSeqElem(p: BProc, n, x, y: PNode, d: var TLoc) =
     ty = skipTypes(ty.lastSon, abstractVarRange) # emit range check:
   if optBoundsCheck in p.options:
     linefmt(p, cpsStmts,
-            "if ($1 < 0 || $1 >= $2){ #raiseIndexError2($1,$2-1); $3}$n",
-            [rdCharLoc(b), lenExpr(p, a), raiseInstr(p)])
+            "if ($1 < 0 || $1 >= $2){ #raiseIndexError2($1,$2-1); ",
+            [rdCharLoc(b), lenExpr(p, a)])
+    raiseInstr(p, p.s(cpsStmts))
+    linefmt p, cpsStmts, "}$n", []
+
   if d.k == locNone: d.storage = OnHeap
   if skipTypes(a.t, abstractVar).kind in {tyRef, tyPtr}:
     a.r = ropecg(p.module, "(*$1)", [a.r])
@@ -1157,7 +1223,7 @@ proc genEcho(p: BProc, n: PNode) =
   internalAssert p.config, n.kind == nkBracket
   if p.config.target.targetOS == osGenode:
     # echo directly to the Genode LOG session
-    var args: Rope = nil
+    var args: Rope = ""
     var a: TLoc
     for i, it in n.sons:
       if it.skipConv.kind == nkNilLit:
@@ -1216,8 +1282,8 @@ proc genStrConcat(p: BProc, e: PNode, d: var TLoc) =
   var a, tmp: TLoc
   getTemp(p, e.typ, tmp)
   var L = 0
-  var appends: Rope = nil
-  var lens: Rope = nil
+  var appends: Rope = ""
+  var lens: Rope = ""
   for i in 0..<e.len - 1:
     # compute the length expression:
     initLocExpr(p, e[i + 1], a)
@@ -1334,7 +1400,7 @@ proc rawGenNew(p: BProc, a: var TLoc, sizeExpr: Rope; needsInit: bool) =
   let refType = typ.skipTypes(abstractInstOwned)
   assert refType.kind == tyRef
   let bt = refType.lastSon
-  if sizeExpr.isNil:
+  if sizeExpr == "":
     sizeExpr = "sizeof($1)" % [getTypeDesc(p.module, bt)]
 
   if optTinyRtti in p.config.globalOptions:
@@ -1390,7 +1456,7 @@ proc genNew(p: BProc, e: PNode) =
     initLocExpr(p, e[2], se)
     rawGenNew(p, a, se.rdLoc, needsInit = true)
   else:
-    rawGenNew(p, a, nil, needsInit = true)
+    rawGenNew(p, a, "", needsInit = true)
   gcUsage(p.config, e)
 
 proc genNewSeqAux(p: BProc, dest: TLoc, length: Rope; lenIsZero: bool) =
@@ -1460,8 +1526,9 @@ proc rawConstExpr(p: BProc, n: PNode; d: var TLoc) =
   if id == p.module.labels:
     # expression not found in the cache:
     inc(p.module.labels)
-    p.module.s[cfsData].addf("static NIM_CONST $1 $2 = $3;$n",
-          [getTypeDesc(p.module, t), d.r, genBracedInit(p, n, isConst = true, t)])
+    p.module.s[cfsData].addf("static NIM_CONST $1 $2 = ", [getTypeDesc(p.module, t), d.r])
+    genBracedInit(p, n, isConst = true, t, p.module.s[cfsData])
+    p.module.s[cfsData].addf(";$n", [])
 
 proc handleConstExpr(p: BProc, n: PNode, d: var TLoc): bool =
   if d.k == locNone and n.len > ord(n.kind == nkObjConstr) and n.isDeepConstExpr:
@@ -1498,7 +1565,7 @@ proc genObjConstr(p: BProc, e: PNode, d: var TLoc) =
     getTemp(p, t, tmp)
     r = rdLoc(tmp)
     if isRef:
-      rawGenNew(p, tmp, nil, needsInit = nfAllFieldsSet notin e.flags)
+      rawGenNew(p, tmp, "", needsInit = nfAllFieldsSet notin e.flags)
       t = t.lastSon.skipTypes(abstractInstOwned)
       r = "(*$1)" % [r]
       gcUsage(p.config, e)
@@ -1514,8 +1581,8 @@ proc genObjConstr(p: BProc, e: PNode, d: var TLoc) =
     var tmp2: TLoc
     tmp2.r = r
     let field = lookupFieldAgain(p, ty, it[0].sym, tmp2.r)
-    if field.loc.r == nil: fillObjectFields(p.module, ty)
-    if field.loc.r == nil: internalError(p.config, e.info, "genObjConstr")
+    if field.loc.r == "": fillObjectFields(p.module, ty)
+    if field.loc.r == "": internalError(p.config, e.info, "genObjConstr")
     if it.len == 3 and optFieldCheck in p.options:
       genFieldCheck(p, it[2], r, field)
     tmp2.r.add(".")
@@ -1548,18 +1615,21 @@ proc genSeqConstr(p: BProc, n: PNode, d: var TLoc) =
   elif d.k == locNone:
     getTemp(p, n.typ, d)
 
-  let l = intLiteral(n.len)
+  var lit = newRopeAppender()
+  intLiteral(n.len, lit)
   if optSeqDestructors in p.config.globalOptions:
     let seqtype = n.typ
     linefmt(p, cpsStmts, "$1.len = $2; $1.p = ($4*) #newSeqPayload($2, sizeof($3), NIM_ALIGNOF($3));$n",
-      [rdLoc dest[], l, getTypeDesc(p.module, seqtype.lastSon),
+      [rdLoc dest[], lit, getTypeDesc(p.module, seqtype.lastSon),
       getSeqPayloadType(p.module, seqtype)])
   else:
     # generate call to newSeq before adding the elements per hand:
-    genNewSeqAux(p, dest[], l, n.len == 0)
+    genNewSeqAux(p, dest[], lit, n.len == 0)
   for i in 0..<n.len:
     initLoc(arr, locExpr, n[i], OnHeap)
-    arr.r = ropecg(p.module, "$1$3[$2]", [rdLoc(dest[]), intLiteral(i), dataField(p)])
+    var lit = newRopeAppender()
+    intLiteral(i, lit)
+    arr.r = ropecg(p.module, "$1$3[$2]", [rdLoc(dest[]), lit, dataField(p)])
     arr.storage = OnHeap            # we know that sequences are on the heap
     expr(p, n[i], arr)
   gcUsage(p.config, n)
@@ -1585,16 +1655,20 @@ proc genArrToSeq(p: BProc, n: PNode, d: var TLoc) =
       [rdLoc d, L, getTypeDesc(p.module, seqtype.lastSon),
       getSeqPayloadType(p.module, seqtype)])
   else:
-    genNewSeqAux(p, d, intLiteral(L), L == 0)
+    var lit = newRopeAppender()
+    intLiteral(L, lit)
+    genNewSeqAux(p, d, lit, L == 0)
   initLocExpr(p, n[1], a)
   # bug #5007; do not produce excessive C source code:
   if L < 10:
     for i in 0..<L:
       initLoc(elem, locExpr, lodeTyp elemType(skipTypes(n.typ, abstractInst)), OnHeap)
-      elem.r = ropecg(p.module, "$1$3[$2]", [rdLoc(d), intLiteral(i), dataField(p)])
+      var lit = newRopeAppender()
+      intLiteral(i, lit)
+      elem.r = ropecg(p.module, "$1$3[$2]", [rdLoc(d), lit, dataField(p)])
       elem.storage = OnHeap # we know that sequences are on the heap
       initLoc(arr, locExpr, lodeTyp elemType(skipTypes(n[1].typ, abstractInst)), a.storage)
-      arr.r = ropecg(p.module, "$1[$2]", [rdLoc(a), intLiteral(i)])
+      arr.r = ropecg(p.module, "$1[$2]", [rdLoc(a), lit])
       genAssignment(p, elem, arr, {needToCopy})
   else:
     var i: TLoc
@@ -1628,37 +1702,37 @@ proc genNewFinalize(p: BProc, e: PNode) =
   genObjectInit(p, cpsStmts, bt, a, constructRefObj)
   gcUsage(p.config, e)
 
-proc genOfHelper(p: BProc; dest: PType; a: Rope; info: TLineInfo): Rope =
+proc genOfHelper(p: BProc; dest: PType; a: Rope; info: TLineInfo; result: var Rope) =
   if optTinyRtti in p.config.globalOptions:
     let ti = genTypeInfo2Name(p.module, dest)
     inc p.module.labels
     let cache = "Nim_OfCheck_CACHE" & p.module.labels.rope
     p.module.s[cfsVars].addf("static TNimTypeV2* $#[2];$n", [cache])
-    result = ropecg(p.module, "#isObjWithCache($#.m_type, $#, $#)", [a, ti, cache])
+    appcg(p.module, result, "#isObjWithCache($#.m_type, $#, $#)", [a, ti, cache])
   else:
     # unfortunately 'genTypeInfoV1' sets tfObjHasKids as a side effect, so we
     # have to call it here first:
     let ti = genTypeInfoV1(p.module, dest, info)
     if tfFinal in dest.flags or (objHasKidsValid in p.module.flags and
                                 tfObjHasKids notin dest.flags):
-      result = "$1.m_type == $2" % [a, ti]
+      result.add "$1.m_type == $2" % [a, ti]
     else:
-      discard cgsym(p.module, "TNimType")
+      cgsym(p.module, "TNimType")
       inc p.module.labels
       let cache = "Nim_OfCheck_CACHE" & p.module.labels.rope
       p.module.s[cfsVars].addf("static TNimType* $#[2];$n", [cache])
-      result = ropecg(p.module, "#isObjWithCache($#.m_type, $#, $#)", [a, ti, cache])
+      appcg(p.module, result, "#isObjWithCache($#.m_type, $#, $#)", [a, ti, cache])
     when false:
       # former version:
-      result = ropecg(p.module, "#isObj($1.m_type, $2)",
-                    [a, genTypeInfoV1(p.module, dest, info)])
+      appcg(p.module, result, "#isObj($1.m_type, $2)",
+            [a, genTypeInfoV1(p.module, dest, info)])
 
 proc genOf(p: BProc, x: PNode, typ: PType, d: var TLoc) =
   var a: TLoc
   initLocExpr(p, x, a)
   var dest = skipTypes(typ, typedescPtrs)
   var r = rdLoc(a)
-  var nilCheck: Rope = nil
+  var nilCheck: Rope = ""
   var t = skipTypes(a.t, abstractInstOwned)
   while t.kind in {tyVar, tyLent, tyPtr, tyRef}:
     if t.kind notin {tyVar, tyLent}: nilCheck = r
@@ -1668,16 +1742,27 @@ proc genOf(p: BProc, x: PNode, typ: PType, d: var TLoc) =
   discard getTypeDesc(p.module, t)
   if not p.module.compileToCpp:
     while t.kind == tyObject and t[0] != nil:
-      r.add(~".Sup")
+      r.add(".Sup")
       t = skipTypes(t[0], skipPtrs)
   if isObjLackingTypeField(t):
     globalError(p.config, x.info,
       "no 'of' operator available for pure objects")
-  if nilCheck != nil:
-    r = ropecg(p.module, "(($1) && ($2))", [nilCheck, genOfHelper(p, dest, r, x.info)])
+
+  var ro = newRopeAppender()
+  genOfHelper(p, dest, r, x.info, ro)
+  var ofExpr = newRopeAppender()
+  ofExpr.add "("
+  if nilCheck != "":
+    ofExpr.add "("
+    ofExpr.add nilCheck
+    ofExpr.add ") && ("
+    ofExpr.add ro
+    ofExpr.add "))"
   else:
-    r = ropecg(p.module, "($1)", [genOfHelper(p, dest, r, x.info)])
-  putIntoDest(p, d, x, r, a.storage)
+    ofExpr.add ro
+    ofExpr.add ")"
+
+  putIntoDest(p, d, x, ofExpr, a.storage)
 
 proc genOf(p: BProc, n: PNode, d: var TLoc) =
   genOf(p, n[1], n[2].typ, d)
@@ -1734,14 +1819,15 @@ proc genRepr(p: BProc, e: PNode, d: var TLoc) =
                                a.storage)
   gcUsage(p.config, e)
 
-proc rdMType(p: BProc; a: TLoc; nilCheck: var Rope; enforceV1 = false): Rope =
-  result = rdLoc(a)
+proc rdMType(p: BProc; a: TLoc; nilCheck: var Rope; result: var Rope; enforceV1 = false) =
+  var derefs = rdLoc(a)
   var t = skipTypes(a.t, abstractInst)
   while t.kind in {tyVar, tyLent, tyPtr, tyRef}:
-    if t.kind notin {tyVar, tyLent}: nilCheck = result
+    if t.kind notin {tyVar, tyLent}: nilCheck = derefs
     if t.kind notin {tyVar, tyLent} or not p.module.compileToCpp:
-      result = "(*$1)" % [result]
+      derefs = "(*$1)" % [derefs]
     t = skipTypes(t.lastSon, abstractInst)
+  result.add derefs
   discard getTypeDesc(p.module, t)
   if not p.module.compileToCpp:
     while t.kind == tyObject and t[0] != nil:
@@ -1752,7 +1838,7 @@ proc rdMType(p: BProc; a: TLoc; nilCheck: var Rope; enforceV1 = false): Rope =
     result.add "->typeInfoV1"
 
 proc genGetTypeInfo(p: BProc, e: PNode, d: var TLoc) =
-  discard cgsym(p.module, "TNimType")
+  cgsym(p.module, "TNimType")
   let t = e[1].typ
   # ordinary static type information
   putIntoDest(p, d, e, genTypeInfoV1(p.module, t, e.info))
@@ -1765,16 +1851,20 @@ proc genGetTypeInfoV2(p: BProc, e: PNode, d: var TLoc) =
   else:
     var a: TLoc
     initLocExpr(p, e[1], a)
-    var nilCheck = Rope(nil)
+    var nilCheck = ""
     # use the dynamic type stored at offset 0:
-    putIntoDest(p, d, e, rdMType(p, a, nilCheck))
+    var rt = newRopeAppender()
+    rdMType(p, a, nilCheck, rt)
+    putIntoDest(p, d, e, rt)
 
 proc genAccessTypeField(p: BProc; e: PNode; d: var TLoc) =
   var a: TLoc
   initLocExpr(p, e[1], a)
-  var nilCheck = Rope(nil)
+  var nilCheck = ""
   # use the dynamic type stored at offset 0:
-  putIntoDest(p, d, e, rdMType(p, a, nilCheck))
+  var rt = newRopeAppender()
+  rdMType(p, a, nilCheck, rt)
+  putIntoDest(p, d, e, rt)
 
 template genDollar(p: BProc, n: PNode, d: var TLoc, frmt: string) =
   var a: TLoc
@@ -1902,14 +1992,17 @@ proc genSwap(p: BProc, e: PNode, d: var TLoc) =
   genAssignment(p, a, b, {})
   genAssignment(p, b, tmp, {})
 
-proc rdSetElemLoc(conf: ConfigRef; a: TLoc, typ: PType): Rope =
+proc rdSetElemLoc(conf: ConfigRef; a: TLoc, typ: PType; result: var Rope) =
   # read a location of an set element; it may need a subtraction operation
   # before the set operation
-  result = rdCharLoc(a)
+  result.add "("
+  result.add rdCharLoc(a)
   let setType = typ.skipTypes(abstractPtrs)
   assert(setType.kind == tySet)
   if firstOrd(conf, setType) != 0:
-    result = "($1- $2)" % [result, rope(firstOrd(conf, setType))]
+    result.add " - "
+    result.add rope(firstOrd(conf, setType))
+  result.add ")"
 
 proc fewCmps(conf: ConfigRef; s: PNode): bool =
   # this function estimates whether it is better to emit code
@@ -1923,7 +2016,9 @@ proc fewCmps(conf: ConfigRef; s: PNode): bool =
     result = s.len <= 8  # 8 seems to be a good value
 
 template binaryExprIn(p: BProc, e: PNode, a, b, d: var TLoc, frmt: string) =
-  putIntoDest(p, d, e, frmt % [rdLoc(a), rdSetElemLoc(p.config, b, a.t)])
+  var elem = newRopeAppender()
+  rdSetElemLoc(p.config, b, a.t, elem)
+  putIntoDest(p, d, e, frmt % [rdLoc(a), elem])
 
 proc genInExprAux(p: BProc, e: PNode, a, b, d: var TLoc) =
   case int(getSize(p.config, skipTypes(e[1].typ, abstractVar)))
@@ -1938,7 +2033,9 @@ template binaryStmtInExcl(p: BProc, e: PNode, d: var TLoc, frmt: string) =
   assert(d.k == locNone)
   initLocExpr(p, e[1], a)
   initLocExpr(p, e[2], b)
-  lineF(p, cpsStmts, frmt, [rdLoc(a), rdSetElemLoc(p.config, b, a.t)])
+  var elem = newRopeAppender()
+  rdSetElemLoc(p.config, b, a.t, elem)
+  lineF(p, cpsStmts, frmt, [rdLoc(a), elem])
 
 proc genInOp(p: BProc, e: PNode, d: var TLoc) =
   var a, b, x, y: TLoc
@@ -2131,16 +2228,23 @@ proc genRangeChck(p: BProc, n: PNode, d: var TLoc) =
 
     # emit range check:
     if n0t.kind in {tyUInt, tyUInt64}:
-      linefmt(p, cpsStmts, "if ($1 > ($6)($3)){ #raiseRangeErrorNoArgs(); $5}$n",
-        [rdCharLoc(a), genLiteral(p, n[1], dest), genLiteral(p, n[2], dest),
-        raiser, raiseInstr(p), getTypeDesc(p.module, n0t)])
+      var first = newRopeAppender()
+      genLiteral(p, n[1], dest, first)
+      var last = newRopeAppender()
+      genLiteral(p, n[2], dest, last)
+      linefmt(p, cpsStmts, "if ($1 > ($5)($3)){ #raiseRangeErrorNoArgs(); ",
+        [rdCharLoc(a), first, last,
+        raiser, getTypeDesc(p.module, n0t)])
+      raiseInstr(p, p.s(cpsStmts))
+      linefmt p, cpsStmts, "}$n", []
+
     else:
       let raiser =
         case skipTypes(n.typ, abstractVarRange).kind
         of tyUInt..tyUInt64, tyChar: "raiseRangeErrorU"
         of tyFloat..tyFloat128: "raiseRangeErrorF"
         else: "raiseRangeErrorI"
-      discard cgsym(p.module, raiser)
+      cgsym(p.module, raiser)
 
       let boundaryCast =
         if n0t.skipTypes(abstractVarRange).kind in {tyUInt, tyUInt32, tyUInt64} or
@@ -2148,9 +2252,16 @@ proc genRangeChck(p: BProc, n: PNode, d: var TLoc) =
           "(NI64)"
         else:
           ""
-      linefmt(p, cpsStmts, "if ($6($1) < $2 || $6($1) > $3){ $4($1, $2, $3); $5}$n",
-        [rdCharLoc(a), genLiteral(p, n[1], dest), genLiteral(p, n[2], dest),
-        raiser, raiseInstr(p), boundaryCast])
+      var first = newRopeAppender()
+      genLiteral(p, n[1], dest, first)
+      var last = newRopeAppender()
+      genLiteral(p, n[2], dest, last)
+      linefmt(p, cpsStmts, "if ($5($1) < $2 || $5($1) > $3){ $4($1, $2, $3); ",
+        [rdCharLoc(a), first, last,
+        raiser, boundaryCast])
+      raiseInstr(p, p.s(cpsStmts))
+      linefmt p, cpsStmts, "}$n", []
+
   putIntoDest(p, d, n, "(($1) ($2))" %
       [getTypeDesc(p.module, dest), rdCharLoc(a)], a.storage)
 
@@ -2204,9 +2315,15 @@ proc binaryFloatArith(p: BProc, e: PNode, d: var TLoc, m: TMagic) =
                               [opr[m], rdLoc(a), rdLoc(b),
                               getSimpleTypeDesc(p.module, e[1].typ)]))
     if optNaNCheck in p.options:
-      linefmt(p, cpsStmts, "if ($1 != $1){ #raiseFloatInvalidOp(); $2}$n", [rdLoc(d), raiseInstr(p)])
+      linefmt(p, cpsStmts, "if ($1 != $1){ #raiseFloatInvalidOp(); ", [rdLoc(d)])
+      raiseInstr(p, p.s(cpsStmts))
+      linefmt p, cpsStmts, "}$n", []
+
     if optInfCheck in p.options:
-      linefmt(p, cpsStmts, "if ($1 != 0.0 && $1*0.5 == $1) { #raiseFloatOverflow($1); $2}$n", [rdLoc(d), raiseInstr(p)])
+      linefmt(p, cpsStmts, "if ($1 != 0.0 && $1*0.5 == $1) { #raiseFloatOverflow($1); ", [rdLoc(d)])
+      raiseInstr(p, p.s(cpsStmts))
+      linefmt p, cpsStmts, "}$n", []
+
   else:
     binaryArith(p, e, d, m)
 
@@ -2382,7 +2499,7 @@ proc genMagicExpr(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
     if optTinyRtti in p.config.globalOptions:
       var a: TLoc
       initLocExpr(p, e[1], a)
-      rawGenNew(p, a, nil, needsInit = true)
+      rawGenNew(p, a, "", needsInit = true)
       gcUsage(p.config, e)
     else:
       genNewFinalize(p, e)
@@ -2445,7 +2562,7 @@ proc genMagicExpr(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
       let wasDeclared = containsOrIncl(p.module.declaredProtos, prc.id)
       # Make the function behind the magic get actually generated - this will
       # not lead to a forward declaration! The genCall will lead to one.
-      discard cgsym(p.module, $opr.loc.r)
+      cgsym(p.module, $opr.loc.r)
       # make sure we have pointer-initialising code for hot code reloading
       if not wasDeclared and p.hcrOn:
         p.module.s[cfsDynLibInit].addf("\t$1 = ($2) hcrGetProc($3, \"$1\");$n",
@@ -2500,7 +2617,9 @@ proc genSetConstr(p: BProc, e: PNode, d: var TLoc) =
   var
     a, b, idx: TLoc
   if nfAllConst in e.flags:
-    putIntoDest(p, d, e, genSetNode(p, e))
+    var elem = newRopeAppender()
+    genSetNode(p, e, elem)
+    putIntoDest(p, d, e, elem)
   else:
     if d.k == locNone: getTemp(p, e.typ, d)
     if getSize(p.config, e.typ) > 8:
@@ -2512,13 +2631,19 @@ proc genSetConstr(p: BProc, e: PNode, d: var TLoc) =
           getTemp(p, getSysType(p.module.g.graph, unknownLineInfo, tyInt), idx) # our counter
           initLocExpr(p, it[0], a)
           initLocExpr(p, it[1], b)
+          var aa = newRopeAppender()
+          rdSetElemLoc(p.config, a, e.typ, aa)
+          var bb = newRopeAppender()
+          rdSetElemLoc(p.config, b, e.typ, bb)
           lineF(p, cpsStmts, "for ($1 = $3; $1 <= $4; $1++) $n" &
               "$2[(NU)($1)>>3] |=(1U<<((NU)($1)&7U));$n", [rdLoc(idx), rdLoc(d),
-              rdSetElemLoc(p.config, a, e.typ), rdSetElemLoc(p.config, b, e.typ)])
+              aa, bb])
         else:
           initLocExpr(p, it, a)
+          var aa = newRopeAppender()
+          rdSetElemLoc(p.config, a, e.typ, aa)
           lineF(p, cpsStmts, "$1[(NU)($2)>>3] |=(1U<<((NU)($2)&7U));$n",
-               [rdLoc(d), rdSetElemLoc(p.config, a, e.typ)])
+               [rdLoc(d), aa])
     else:
       # small set
       var ts = "NU" & $(getSize(p.config, e.typ) * 8)
@@ -2528,15 +2653,21 @@ proc genSetConstr(p: BProc, e: PNode, d: var TLoc) =
           getTemp(p, getSysType(p.module.g.graph, unknownLineInfo, tyInt), idx) # our counter
           initLocExpr(p, it[0], a)
           initLocExpr(p, it[1], b)
+          var aa = newRopeAppender()
+          rdSetElemLoc(p.config, a, e.typ, aa)
+          var bb = newRopeAppender()
+          rdSetElemLoc(p.config, b, e.typ, bb)
+
           lineF(p, cpsStmts, "for ($1 = $3; $1 <= $4; $1++) $n" &
               "$2 |=(($5)(1)<<(($1)%(sizeof($5)*8)));$n", [
-              rdLoc(idx), rdLoc(d), rdSetElemLoc(p.config, a, e.typ),
-              rdSetElemLoc(p.config, b, e.typ), rope(ts)])
+              rdLoc(idx), rdLoc(d), aa, bb, rope(ts)])
         else:
           initLocExpr(p, it, a)
+          var aa = newRopeAppender()
+          rdSetElemLoc(p.config, a, e.typ, aa)
           lineF(p, cpsStmts,
                "$1 |=(($3)(1)<<(($2)%(sizeof($3)*8)));$n",
-               [rdLoc(d), rdSetElemLoc(p.config, a, e.typ), rope(ts)])
+               [rdLoc(d), aa, rope(ts)])
 
 proc genTupleConstr(p: BProc, n: PNode, d: var TLoc) =
   var rec: TLoc
@@ -2562,8 +2693,10 @@ proc genClosure(p: BProc, n: PNode, d: var TLoc) =
   if isConstClosure(n):
     inc(p.module.labels)
     var tmp = "CNSTCLOSURE" & rope(p.module.labels)
-    p.module.s[cfsData].addf("static NIM_CONST $1 $2 = $3;$n",
-        [getTypeDesc(p.module, n.typ), tmp, genBracedInit(p, n, isConst = true, n.typ)])
+    var data = "static NIM_CONST $1 $2 = " % [getTypeDesc(p.module, n.typ), tmp]
+    genBracedInit(p, n, isConst = true, n.typ, data)
+    data.addf(";$n", [])
+    p.module.s[cfsData].add data
     putIntoDest(p, d, n, tmp, OnStatic)
   else:
     var tmp, a, b: TLoc
@@ -2588,12 +2721,14 @@ proc genArrayConstr(p: BProc, n: PNode, d: var TLoc) =
     if d.k == locNone: getTemp(p, n.typ, d)
     for i in 0..<n.len:
       initLoc(arr, locExpr, lodeTyp elemType(skipTypes(n.typ, abstractInst)), d.storage)
-      arr.r = "$1[$2]" % [rdLoc(d), intLiteral(i)]
+      var lit = newRopeAppender()
+      intLiteral(i, lit)
+      arr.r = "$1[$2]" % [rdLoc(d), lit]
       expr(p, n[i], arr)
 
 proc genComplexConst(p: BProc, sym: PSym, d: var TLoc) =
   requestConstImpl(p, sym)
-  assert((sym.loc.r != nil) and (sym.loc.t != nil))
+  assert((sym.loc.r != "") and (sym.loc.t != nil))
   putLocIntoDest(p, d, sym.loc)
 
 template genStmtListExprImpl(exprOrStmt) {.dirty.} =
@@ -2601,11 +2736,11 @@ template genStmtListExprImpl(exprOrStmt) {.dirty.} =
   let hasNimFrame = p.prc != nil and
       sfSystemModule notin p.module.module.flags and
       optStackTrace in p.prc.options
-  var frameName: Rope = nil
+  var frameName: Rope = ""
   for i in 0..<n.len - 1:
     let it = n[i]
     if it.kind == nkComesFrom:
-      if hasNimFrame and frameName == nil:
+      if hasNimFrame and frameName == "":
         inc p.labels
         frameName = "FR" & rope(p.labels) & "_"
         let theMacro = it[0].sym
@@ -2615,7 +2750,7 @@ template genStmtListExprImpl(exprOrStmt) {.dirty.} =
     else:
       genStmts(p, it)
   if n.len > 0: exprOrStmt
-  if frameName != nil:
+  if frameName != "":
     p.s(cpsStmts).add deinitFrameNoDebug(p, frameName)
 
 proc genStmtListExpr(p: BProc, n: PNode, d: var TLoc) =
@@ -2633,18 +2768,22 @@ proc upConv(p: BProc, n: PNode, d: var TLoc) =
   initLocExpr(p, n[0], a)
   let dest = skipTypes(n.typ, abstractPtrs)
   if optObjCheck in p.options and not isObjLackingTypeField(dest):
-    var nilCheck = Rope(nil)
-    let r = rdMType(p, a, nilCheck)
+    var nilCheck = ""
+    var r = newRopeAppender()
+    rdMType(p, a, nilCheck, r)
     let checkFor = if optTinyRtti in p.config.globalOptions:
                      genTypeInfo2Name(p.module, dest)
                    else:
                      genTypeInfoV1(p.module, dest, n.info)
-    if nilCheck != nil:
-      linefmt(p, cpsStmts, "if ($1 && !#isObj($2, $3)){ #raiseObjectConversionError(); $4}$n",
-              [nilCheck, r, checkFor, raiseInstr(p)])
+    if nilCheck != "":
+      linefmt(p, cpsStmts, "if ($1 && !#isObj($2, $3)){ #raiseObjectConversionError(); ",
+              [nilCheck, r, checkFor])
     else:
-      linefmt(p, cpsStmts, "if (!#isObj($1, $2)){ #raiseObjectConversionError(); $3}$n",
-              [r, checkFor, raiseInstr(p)])
+      linefmt(p, cpsStmts, "if (!#isObj($1, $2)){ #raiseObjectConversionError(); ",
+              [r, checkFor])
+    raiseInstr(p, p.s(cpsStmts))
+    linefmt p, cpsStmts, "}$n", []
+
   if n[0].typ.kind != tyObject:
     if n.isLValue:
       putIntoDest(p, d, n,
@@ -2693,8 +2832,10 @@ proc exprComplexConst(p: BProc, n: PNode, d: var TLoc) =
   if id == p.module.labels:
     # expression not found in the cache:
     inc(p.module.labels)
-    p.module.s[cfsData].addf("static NIM_CONST $1 $2 = $3;$n",
-         [getTypeDesc(p.module, t, skConst), tmp, genBracedInit(p, n, isConst = true, t)])
+    p.module.s[cfsData].addf("static NIM_CONST $1 $2 = ",
+         [getTypeDesc(p.module, t, skConst), tmp])
+    genBracedInit(p, n, isConst = true, t, p.module.s[cfsData])
+    p.module.s[cfsData].addf(";$n", [])
 
   if d.k == locNone:
     fillLoc(d, locData, n, tmp, OnStatic)
@@ -2709,14 +2850,15 @@ proc genConstSetup(p: BProc; sym: PSym): bool =
   let m = p.module
   useHeader(m, sym)
   if sym.loc.k == locNone:
-    fillLoc(sym.loc, locData, sym.ast, mangleName(p.module, sym), OnStatic)
+    fillBackendName(p.module, sym)
+    fillLoc(sym.loc, locData, sym.ast, OnStatic)
   if m.hcrOn: incl(sym.loc.flags, lfIndirect)
   result = lfNoDecl notin sym.loc.flags
 
 proc genConstHeader(m, q: BModule; p: BProc, sym: PSym) =
-  if sym.loc.r == nil:
+  if sym.loc.r == "":
     if not genConstSetup(p, sym): return
-  assert(sym.loc.r != nil, $sym.name.s & $sym.itemId)
+  assert(sym.loc.r != "", $sym.name.s & $sym.itemId)
   if m.hcrOn:
     m.s[cfsVars].addf("static $1* $2;$n", [getTypeDesc(m, sym.loc.t, skVar), sym.loc.r]);
     m.initProc.procSec(cpsLocals).addf(
@@ -2732,9 +2874,12 @@ proc genConstHeader(m, q: BModule; p: BProc, sym: PSym) =
 proc genConstDefinition(q: BModule; p: BProc; sym: PSym) =
   # add a suffix for hcr - will later init the global pointer with this data
   let actualConstName = if q.hcrOn: sym.loc.r & "_const" else: sym.loc.r
-  q.s[cfsData].addf("N_LIB_PRIVATE NIM_CONST $1 $2 = $3;$n",
-      [getTypeDesc(q, sym.typ), actualConstName,
-      genBracedInit(q.initProc, sym.ast, isConst = true, sym.typ)])
+  var data = newRopeAppender()
+  data.addf("N_LIB_PRIVATE NIM_CONST $1 $2 = ",
+           [getTypeDesc(q, sym.typ), actualConstName])
+  genBracedInit(q.initProc, sym.ast, isConst = true, sym.typ, data)
+  data.addf(";$n", [])
+  q.s[cfsData].add data
   if q.hcrOn:
     # generate the global pointer with the real name
     q.s[cfsVars].addf("static $1* $2;$n", [getTypeDesc(q, sym.loc.t, skVar), sym.loc.r])
@@ -2786,15 +2931,17 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
         genProcPrototype(p.module, sym)
       else:
         genProc(p.module, sym)
-      if sym.loc.r == nil or sym.loc.lode == nil:
+      if sym.loc.r == "" or sym.loc.lode == nil:
         internalError(p.config, n.info, "expr: proc not init " & sym.name.s)
       putLocIntoDest(p, d, sym.loc)
     of skConst:
       if isSimpleConst(sym.typ):
-        putIntoDest(p, d, n, genLiteral(p, sym.ast, sym.typ), OnStatic)
+        var lit = newRopeAppender()
+        genLiteral(p, sym.ast, sym.typ, lit)
+        putIntoDest(p, d, n, lit, OnStatic)
       elif useAliveDataFromDce in p.module.flags:
         genConstHeader(p.module, p.module, p, sym)
-        assert((sym.loc.r != nil) and (sym.loc.t != nil))
+        assert((sym.loc.r != "") and (sym.loc.t != nil))
         putLocIntoDest(p, d, sym.loc)
       else:
         genComplexConst(p, sym, d)
@@ -2809,7 +2956,7 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
         if sfCompileTime in sym.flags:
           genSingleVar(p, sym, n, astdef(sym))
 
-      if sym.loc.r == nil or sym.loc.t == nil:
+      if sym.loc.r == "" or sym.loc.t == nil:
         #echo "FAILED FOR PRCO ", p.prc.name.s
         #echo renderTree(p.prc.ast, {renderIds})
         internalError p.config, n.info, "expr: var not init " & sym.name.s & "_" & $sym.id
@@ -2824,17 +2971,17 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
     of skTemp:
       when false:
         # this is more harmful than helpful.
-        if sym.loc.r == nil:
+        if sym.loc.r == "":
           # we now support undeclared 'skTemp' variables for easier
           # transformations in other parts of the compiler:
           assignLocalVar(p, n)
-      if sym.loc.r == nil or sym.loc.t == nil:
+      if sym.loc.r == "" or sym.loc.t == nil:
         #echo "FAILED FOR PRCO ", p.prc.name.s
         #echo renderTree(p.prc.ast, {renderIds})
         internalError(p.config, n.info, "expr: temp not init " & sym.name.s & "_" & $sym.id)
       putLocIntoDest(p, d, sym.loc)
     of skParam:
-      if sym.loc.r == nil or sym.loc.t == nil:
+      if sym.loc.r == "" or sym.loc.t == nil:
         # echo "FAILED FOR PRCO ", p.prc.name.s
         # debug p.prc.typ.n
         # echo renderTree(p.prc.ast, {renderIds})
@@ -2843,12 +2990,17 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
     else: internalError(p.config, n.info, "expr(" & $sym.kind & "); unknown symbol")
   of nkNilLit:
     if not isEmptyType(n.typ):
-      putIntoDest(p, d, n, genLiteral(p, n))
+      var lit = newRopeAppender()
+      genLiteral(p, n, lit)
+      putIntoDest(p, d, n, lit)
   of nkStrLit..nkTripleStrLit:
-    putDataIntoDest(p, d, n, genLiteral(p, n))
-  of nkIntLit..nkUInt64Lit,
-     nkFloatLit..nkFloat128Lit, nkCharLit:
-    putIntoDest(p, d, n, genLiteral(p, n))
+    var lit = newRopeAppender()
+    genLiteral(p, n, lit)
+    putDataIntoDest(p, d, n, lit)
+  of nkIntLit..nkUInt64Lit, nkFloatLit..nkFloat128Lit, nkCharLit:
+    var lit = newRopeAppender()
+    genLiteral(p, n, lit)
+    putIntoDest(p, d, n, lit)
   of nkCall, nkHiddenCallConv, nkInfix, nkPrefix, nkPostfix, nkCommand,
      nkCallStrLit:
     genLineDir(p, n) # may be redundant, it is generated in fixupCall as well
@@ -2868,7 +3020,9 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
         genCall(p, n, d)
   of nkCurly:
     if isDeepConstExpr(n) and n.len != 0:
-      putIntoDest(p, d, n, genSetNode(p, n))
+      var lit = newRopeAppender()
+      genSetNode(p, n, lit)
+      putIntoDest(p, d, n, lit)
     else:
       genSetConstr(p, n, d)
   of nkBracket:
@@ -2908,7 +3062,7 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
   of nkLambdaKinds:
     var sym = n[namePos].sym
     genProc(p.module, sym)
-    if sym.loc.r == nil or sym.loc.lode == nil:
+    if sym.loc.r == "" or sym.loc.lode == nil:
       internalError(p.config, n.info, "expr: proc not init " & sym.name.s)
     putLocIntoDest(p, d, sym.loc)
   of nkClosure: genClosure(p, n, d)
@@ -3001,52 +3155,48 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
   of nkMixinStmt, nkBindStmt: discard
   else: internalError(p.config, n.info, "expr(" & $n.kind & "); unknown node kind")
 
-proc genNamedConstExpr(p: BProc, n: PNode; isConst: bool): Rope =
-  if n.kind == nkExprColonExpr: result = genBracedInit(p, n[1], isConst, n[0].typ)
-  else: result = genBracedInit(p, n, isConst, n.typ)
-
-proc getDefaultValue(p: BProc; typ: PType; info: TLineInfo): Rope =
+proc getDefaultValue(p: BProc; typ: PType; info: TLineInfo; result: var Rope) =
   var t = skipTypes(typ, abstractRange+{tyOwned}-{tyTypeDesc})
   case t.kind
-  of tyBool: result = rope"NIM_FALSE"
-  of tyEnum, tyChar, tyInt..tyInt64, tyUInt..tyUInt64: result = rope"0"
-  of tyFloat..tyFloat128: result = rope"0.0"
+  of tyBool: result.add rope"NIM_FALSE"
+  of tyEnum, tyChar, tyInt..tyInt64, tyUInt..tyUInt64: result.add rope"0"
+  of tyFloat..tyFloat128: result.add rope"0.0"
   of tyCstring, tyVar, tyLent, tyPointer, tyPtr, tyUntyped,
      tyTyped, tyTypeDesc, tyStatic, tyRef, tyNil:
-    result = rope"NIM_NIL"
+    result.add rope"NIM_NIL"
   of tyString, tySequence:
     if optSeqDestructors in p.config.globalOptions:
-      result = rope"{0, NIM_NIL}"
+      result.add "{0, NIM_NIL}"
     else:
-      result = rope"NIM_NIL"
+      result.add "NIM_NIL"
   of tyProc:
     if t.callConv != ccClosure:
-      result = rope"NIM_NIL"
+      result.add "NIM_NIL"
     else:
-      result = rope"{NIM_NIL, NIM_NIL}"
+      result.add "{NIM_NIL, NIM_NIL}"
   of tyObject:
     var count = 0
     result.add "{"
     getNullValueAuxT(p, t, t, t.n, nil, result, count, true, info)
     result.add "}"
   of tyTuple:
-    result = rope"{"
+    result.add "{"
     for i in 0..<t.len:
       if i > 0: result.add ", "
-      result.add getDefaultValue(p, t[i], info)
+      getDefaultValue(p, t[i], info, result)
     result.add "}"
   of tyArray:
-    result = rope"{"
+    result.add "{"
     for i in 0..<toInt(lengthOrd(p.config, t.sons[0])):
       if i > 0: result.add ", "
-      result.add getDefaultValue(p, t.sons[1], info)
+      getDefaultValue(p, t.sons[1], info, result)
     result.add "}"
     #result = rope"{}"
   of tyOpenArray, tyVarargs:
-    result = rope"{NIM_NIL, 0}"
+    result.add "{NIM_NIL, 0}"
   of tySet:
-    if mapSetType(p.config, t) == ctArray: result = rope"{}"
-    else: result = rope"0"
+    if mapSetType(p.config, t) == ctArray: result.add "{}"
+    else: result.add "0"
   else:
     globalError(p.config, info, "cannot create null element for: " & $t.kind)
 
@@ -3110,13 +3260,13 @@ proc getNullValueAux(p: BProc; t: PType; obj, constOrNil: PNode,
       for i in 1..<constOrNil.len:
         if constOrNil[i].kind == nkExprColonExpr:
           if constOrNil[i][0].sym.name.id == field.name.id:
-            result.add genBracedInit(p, constOrNil[i][1], isConst, field.typ)
+            genBracedInit(p, constOrNil[i][1], isConst, field.typ, result)
             return
         elif i == field.position:
-          result.add genBracedInit(p, constOrNil[i], isConst, field.typ)
+          genBracedInit(p, constOrNil[i], isConst, field.typ, result)
           return
     # not found, produce default value:
-    result.add getDefaultValue(p, field.typ, info)
+    getDefaultValue(p, field.typ, info, result)
   else:
     localError(p.config, info, "cannot create null element for: " & $obj)
 
@@ -3141,36 +3291,36 @@ proc getNullValueAuxT(p: BProc; orig, t: PType; obj, constOrNil: PNode,
   # do not emit '{}' as that is not valid C:
   if oldcount == count: result = oldRes
 
-proc genConstObjConstr(p: BProc; n: PNode; isConst: bool): Rope =
-  result = nil
+proc genConstObjConstr(p: BProc; n: PNode; isConst: bool; result: var Rope) =
   let t = n.typ.skipTypes(abstractInstOwned)
   var count = 0
   #if not isObjLackingTypeField(t) and not p.module.compileToCpp:
   #  result.addf("{$1}", [genTypeInfo(p.module, t)])
   #  inc count
+  result.add "{"
   if t.kind == tyObject:
     getNullValueAuxT(p, t, t, t.n, n, result, count, isConst, n.info)
-  result = "{$1}$n" % [result]
+  result.add("}\n")
 
-proc genConstSimpleList(p: BProc, n: PNode; isConst: bool): Rope =
-  result = rope("{")
+proc genConstSimpleList(p: BProc, n: PNode; isConst: bool; result: var Rope) =
+  result.add "{"
   for i in 0..<n.len:
     let it = n[i]
     if i > 0: result.add ",\n"
-    if it.kind == nkExprColonExpr: result.add genBracedInit(p, it[1], isConst, it[0].typ)
-    else: result.add genBracedInit(p, it, isConst, it.typ)
+    if it.kind == nkExprColonExpr: genBracedInit(p, it[1], isConst, it[0].typ, result)
+    else: genBracedInit(p, it, isConst, it.typ, result)
   result.add("}\n")
 
-proc genConstTuple(p: BProc, n: PNode; isConst: bool; tup: PType): Rope =
-  result = rope("{")
+proc genConstTuple(p: BProc, n: PNode; isConst: bool; tup: PType; result: var Rope) =
+  result.add "{"
   for i in 0..<n.len:
     let it = n[i]
     if i > 0: result.add ",\n"
-    if it.kind == nkExprColonExpr: result.add genBracedInit(p, it[1], isConst, tup[i])
-    else: result.add genBracedInit(p, it, isConst, tup[i])
+    if it.kind == nkExprColonExpr: genBracedInit(p, it[1], isConst, tup[i], result)
+    else: genBracedInit(p, it, isConst, tup[i], result)
   result.add("}\n")
 
-proc genConstSeq(p: BProc, n: PNode, t: PType; isConst: bool): Rope =
+proc genConstSeq(p: BProc, n: PNode, t: PType; isConst: bool; result: var Rope) =
   var data = "{{$1, $1 | NIM_STRLIT_FLAG}" % [n.len.rope]
   let base = t.skipTypes(abstractInst)[0]
   if n.len > 0:
@@ -3178,44 +3328,44 @@ proc genConstSeq(p: BProc, n: PNode, t: PType; isConst: bool): Rope =
     data.add(", {")
     for i in 0..<n.len:
       if i > 0: data.addf(",$n", [])
-      data.add genBracedInit(p, n[i], isConst, base)
+      genBracedInit(p, n[i], isConst, base, data)
     data.add("}")
   data.add("}")
 
-  result = getTempName(p.module)
+  let tmpName = getTempName(p.module)
 
-  appcg(p.module, cfsData,
+  appcg(p.module, cfsStrData,
         "static $5 struct {$n" &
         "  #TGenericSeq Sup;$n" &
         "  $1 data[$2];$n" &
         "} $3 = $4;$n", [
-        getTypeDesc(p.module, base), n.len, result, data,
+        getTypeDesc(p.module, base), n.len, tmpName, data,
         if isConst: "NIM_CONST" else: ""])
 
-  result = "(($1)&$2)" % [getTypeDesc(p.module, t), result]
+  result.add "(($1)&$2)" % [getTypeDesc(p.module, t), tmpName]
 
-proc genConstSeqV2(p: BProc, n: PNode, t: PType; isConst: bool): Rope =
+proc genConstSeqV2(p: BProc, n: PNode, t: PType; isConst: bool; result: var Rope) =
   let base = t.skipTypes(abstractInst)[0]
   var data = rope"{"
   for i in 0..<n.len:
     if i > 0: data.addf(",$n", [])
-    data.add genBracedInit(p, n[i], isConst, base)
+    genBracedInit(p, n[i], isConst, base, data)
   data.add("}")
 
   let payload = getTempName(p.module)
 
-  appcg(p.module, cfsData,
+  appcg(p.module, cfsStrData,
     "static $5 struct {$n" &
     "  NI cap; $1 data[$2];$n" &
     "} $3 = {$2 | NIM_STRLIT_FLAG, $4};$n", [
     getTypeDesc(p.module, base), n.len, payload, data,
     if isConst: "const" else: ""])
-  result = "{$1, ($2*)&$3}" % [rope(n.len), getSeqPayloadType(p.module, t), payload]
+  result.add "{$1, ($2*)&$3}" % [rope(n.len), getSeqPayloadType(p.module, t), payload]
 
-proc genBracedInit(p: BProc, n: PNode; isConst: bool; optionalType: PType): Rope =
+proc genBracedInit(p: BProc, n: PNode; isConst: bool; optionalType: PType; result: var Rope) =
   case n.kind
   of nkHiddenStdConv, nkHiddenSubConv:
-    result = genBracedInit(p, n[1], isConst, n.typ)
+    genBracedInit(p, n[1], isConst, n.typ, result)
   else:
     var ty = tyNone
     var typ: PType = nil
@@ -3230,12 +3380,12 @@ proc genBracedInit(p: BProc, n: PNode; isConst: bool; optionalType: PType): Rope
     case ty
     of tySet:
       let cs = toBitSet(p.config, n)
-      result = genRawSetData(cs, int(getSize(p.config, n.typ)))
+      genRawSetData(cs, int(getSize(p.config, n.typ)), result)
     of tySequence:
       if optSeqDestructors in p.config.globalOptions:
-        result = genConstSeqV2(p, n, typ, isConst)
+        genConstSeqV2(p, n, typ, isConst, result)
       else:
-        result = genConstSeq(p, n, typ, isConst)
+        genConstSeq(p, n, typ, isConst, result)
     of tyProc:
       if typ.callConv == ccClosure and n.safeLen > 1 and n[1].kind == nkNilLit:
         # n.kind could be: nkClosure, nkTupleConstr and maybe others; `n.safeLen`
@@ -3248,44 +3398,45 @@ proc genBracedInit(p: BProc, n: PNode; isConst: bool; optionalType: PType): Rope
         # leading to duplicate code like this:
         # "{NIM_NIL,NIM_NIL}, {NIM_NIL,NIM_NIL}"
         if n[0].kind == nkNilLit:
-          result = ~"{NIM_NIL,NIM_NIL}"
+          result.add "{NIM_NIL,NIM_NIL}"
         else:
           var d: TLoc
           initLocExpr(p, n[0], d)
-          result = "{(($1) $2),NIM_NIL}" % [getClosureType(p.module, typ, clHalfWithEnv), rdLoc(d)]
+          result.add "{(($1) $2),NIM_NIL}" % [getClosureType(p.module, typ, clHalfWithEnv), rdLoc(d)]
       else:
         var d: TLoc
         initLocExpr(p, n, d)
-        result = rdLoc(d)
+        result.add rdLoc(d)
     of tyArray, tyVarargs:
-      result = genConstSimpleList(p, n, isConst)
+      genConstSimpleList(p, n, isConst, result)
     of tyTuple:
-      result = genConstTuple(p, n, isConst, typ)
+      genConstTuple(p, n, isConst, typ, result)
     of tyOpenArray:
       if n.kind != nkBracket:
         internalError(p.config, n.info, "const openArray expression is not an array construction")
 
-      let data = genConstSimpleList(p, n, isConst)
+      var data = newRopeAppender()
+      genConstSimpleList(p, n, isConst, data)
 
       let payload = getTempName(p.module)
       let ctype = getTypeDesc(p.module, typ[0])
       let arrLen = n.len
-      appcg(p.module, cfsData,
+      appcg(p.module, cfsStrData,
         "static $5 $1 $3[$2] = $4;$n", [
         ctype, arrLen, payload, data,
         if isConst: "const" else: ""])
-      result = "{($1*)&$2, $3}" % [ctype, payload, rope arrLen]
+      result.add "{($1*)&$2, $3}" % [ctype, payload, rope arrLen]
 
     of tyObject:
-      result = genConstObjConstr(p, n, isConst)
+      genConstObjConstr(p, n, isConst, result)
     of tyString, tyCstring:
       if optSeqDestructors in p.config.globalOptions and n.kind != nkNilLit and ty == tyString:
-        result = genStringLiteralV2Const(p.module, n, isConst)
+        genStringLiteralV2Const(p.module, n, isConst, result)
       else:
         var d: TLoc
         initLocExpr(p, n, d)
-        result = rdLoc(d)
+        result.add rdLoc(d)
     else:
       var d: TLoc
       initLocExpr(p, n, d)
-      result = rdLoc(d)
+      result.add rdLoc(d)
diff --git a/compiler/ccgliterals.nim b/compiler/ccgliterals.nim
index ee56da5865651..7130c8462880e 100644
--- a/compiler/ccgliterals.nim
+++ b/compiler/ccgliterals.nim
@@ -32,82 +32,87 @@ proc detectSeqVersion(m: BModule): int =
 
 # ----- Version 1: GC'ed strings and seqs --------------------------------
 
-proc genStringLiteralDataOnlyV1(m: BModule, s: string): Rope =
-  discard cgsym(m, "TGenericSeq")
-  result = getTempName(m)
-  m.s[cfsData].addf("STRING_LITERAL($1, $2, $3);$n",
-       [result, makeCString(s), rope(s.len)])
-
-proc genStringLiteralV1(m: BModule; n: PNode): Rope =
+proc genStringLiteralDataOnlyV1(m: BModule, s: string; result: var Rope) =
+  cgsym(m, "TGenericSeq")
+  let tmp = getTempName(m)
+  result.add tmp
+  m.s[cfsStrData].addf("STRING_LITERAL($1, $2, $3);$n",
+       [tmp, makeCString(s), rope(s.len)])
+
+proc genStringLiteralV1(m: BModule; n: PNode; result: var Rope) =
   if s.isNil:
-    result = ropecg(m, "((#NimStringDesc*) NIM_NIL)", [])
+    appcg(m, result, "((#NimStringDesc*) NIM_NIL)", [])
   else:
     let id = nodeTableTestOrSet(m.dataCache, n, m.labels)
     if id == m.labels:
       # string literal not found in the cache:
-      result = ropecg(m, "((#NimStringDesc*) &$1)",
-                      [genStringLiteralDataOnlyV1(m, n.strVal)])
+      appcg(m, result, "((#NimStringDesc*) &", [])
+      genStringLiteralDataOnlyV1(m, n.strVal, result)
+      result.add ")"
     else:
-      result = ropecg(m, "((#NimStringDesc*) &$1$2)",
+      appcg(m, result, "((#NimStringDesc*) &$1$2)",
                       [m.tmpBase, id])
 
 # ------ Version 2: destructor based strings and seqs -----------------------
 
 proc genStringLiteralDataOnlyV2(m: BModule, s: string; result: Rope; isConst: bool) =
-  m.s[cfsData].addf("static $4 struct {$n" &
+  m.s[cfsStrData].addf("static $4 struct {$n" &
        "  NI cap; NIM_CHAR data[$2+1];$n" &
        "} $1 = { $2 | NIM_STRLIT_FLAG, $3 };$n",
        [result, rope(s.len), makeCString(s),
        rope(if isConst: "const" else: "")])
 
-proc genStringLiteralV2(m: BModule; n: PNode; isConst: bool): Rope =
+proc genStringLiteralV2(m: BModule; n: PNode; isConst: bool; result: var Rope) =
   let id = nodeTableTestOrSet(m.dataCache, n, m.labels)
   if id == m.labels:
     let pureLit = getTempName(m)
     genStringLiteralDataOnlyV2(m, n.strVal, pureLit, isConst)
-    result = getTempName(m)
-    discard cgsym(m, "NimStrPayload")
-    discard cgsym(m, "NimStringV2")
+    let tmp = getTempName(m)
+    result.add tmp
+    cgsym(m, "NimStrPayload")
+    cgsym(m, "NimStringV2")
     # string literal not found in the cache:
-    m.s[cfsData].addf("static $4 NimStringV2 $1 = {$2, (NimStrPayload*)&$3};$n",
-          [result, rope(n.strVal.len), pureLit, rope(if isConst: "const" else: "")])
+    m.s[cfsStrData].addf("static $4 NimStringV2 $1 = {$2, (NimStrPayload*)&$3};$n",
+          [tmp, rope(n.strVal.len), pureLit, rope(if isConst: "const" else: "")])
   else:
-    result = getTempName(m)
-    m.s[cfsData].addf("static $4 NimStringV2 $1 = {$2, (NimStrPayload*)&$3};$n",
-          [result, rope(n.strVal.len), m.tmpBase & rope(id),
+    let tmp = getTempName(m)
+    result.add tmp
+    m.s[cfsStrData].addf("static $4 NimStringV2 $1 = {$2, (NimStrPayload*)&$3};$n",
+          [tmp, rope(n.strVal.len), m.tmpBase & rope(id),
           rope(if isConst: "const" else: "")])
 
-proc genStringLiteralV2Const(m: BModule; n: PNode; isConst: bool): Rope =
+proc genStringLiteralV2Const(m: BModule; n: PNode; isConst: bool; result: var Rope) =
   let id = nodeTableTestOrSet(m.dataCache, n, m.labels)
   var pureLit: Rope
   if id == m.labels:
     pureLit = getTempName(m)
-    discard cgsym(m, "NimStrPayload")
-    discard cgsym(m, "NimStringV2")
+    cgsym(m, "NimStrPayload")
+    cgsym(m, "NimStringV2")
     # string literal not found in the cache:
     genStringLiteralDataOnlyV2(m, n.strVal, pureLit, isConst)
   else:
     pureLit = m.tmpBase & rope(id)
-  result = "{$1, (NimStrPayload*)&$2}" % [rope(n.strVal.len), pureLit]
+  result.addf "{$1, (NimStrPayload*)&$2}", [rope(n.strVal.len), pureLit]
 
 # ------ Version selector ---------------------------------------------------
 
 proc genStringLiteralDataOnly(m: BModule; s: string; info: TLineInfo;
-                              isConst: bool): Rope =
+                              isConst: bool; result: var Rope) =
   case detectStrVersion(m)
-  of 0, 1: result = genStringLiteralDataOnlyV1(m, s)
+  of 0, 1: genStringLiteralDataOnlyV1(m, s, result)
   of 2:
-    result = getTempName(m)
-    genStringLiteralDataOnlyV2(m, s, result, isConst)
+    let tmp = getTempName(m)
+    genStringLiteralDataOnlyV2(m, s, tmp, isConst)
+    result.add tmp
   else:
     localError(m.config, info, "cannot determine how to produce code for string literal")
 
-proc genNilStringLiteral(m: BModule; info: TLineInfo): Rope =
-  result = ropecg(m, "((#NimStringDesc*) NIM_NIL)", [])
+proc genNilStringLiteral(m: BModule; info: TLineInfo; result: var Rope) =
+  appcg(m, result, "((#NimStringDesc*) NIM_NIL)", [])
 
-proc genStringLiteral(m: BModule; n: PNode): Rope =
+proc genStringLiteral(m: BModule; n: PNode; result: var Rope) =
   case detectStrVersion(m)
-  of 0, 1: result = genStringLiteralV1(m, n)
-  of 2: result = genStringLiteralV2(m, n, isConst = true)
+  of 0, 1: genStringLiteralV1(m, n, result)
+  of 2: genStringLiteralV2(m, n, isConst = true, result)
   else:
     localError(m.config, n.info, "cannot determine how to produce code for string literal")
diff --git a/compiler/ccgreset.nim b/compiler/ccgreset.nim
index 93b1652f9eba1..5e6456704dd2a 100644
--- a/compiler/ccgreset.nim
+++ b/compiler/ccgreset.nim
@@ -24,7 +24,7 @@ proc specializeResetN(p: BProc, accessor: Rope, n: PNode;
   of nkRecCase:
     if (n[0].kind != nkSym): internalError(p.config, n.info, "specializeResetN")
     let disc = n[0].sym
-    if disc.loc.r == nil: fillObjectFields(p.module, typ)
+    if disc.loc.r == "": fillObjectFields(p.module, typ)
     if disc.loc.t == nil:
       internalError(p.config, n.info, "specializeResetN()")
     lineF(p, cpsStmts, "switch ($1.$2) {$n", [accessor, disc.loc.r])
@@ -42,7 +42,7 @@ proc specializeResetN(p: BProc, accessor: Rope, n: PNode;
   of nkSym:
     let field = n.sym
     if field.typ.kind == tyVoid: return
-    if field.loc.r == nil: fillObjectFields(p.module, typ)
+    if field.loc.r == "": fillObjectFields(p.module, typ)
     if field.loc.t == nil:
       internalError(p.config, n.info, "specializeResetN()")
     specializeResetT(p, "$1.$2" % [accessor, field.loc.r], field.loc.t)
diff --git a/compiler/ccgstmts.nim b/compiler/ccgstmts.nim
index 0980de98feede..7b5f4ff723325 100644
--- a/compiler/ccgstmts.nim
+++ b/compiler/ccgstmts.nim
@@ -15,21 +15,22 @@ const
   stringCaseThreshold = 8
     # above X strings a hash-switch for strings is generated
 
-proc getTraverseProc(p: BProc, v: PSym): Rope =
+proc registerTraverseProc(p: BProc, v: PSym) =
+  var traverseProc = ""
   if p.config.selectedGC in {gcMarkAndSweep, gcHooks, gcRefc} and
       optOwnedRefs notin p.config.globalOptions and
       containsGarbageCollectedRef(v.loc.t):
     # we register a specialized marked proc here; this has the advantage
     # that it works out of the box for thread local storage then :-)
-    result = genTraverseProcForGlobal(p.module, v, v.info)
+    traverseProc = genTraverseProcForGlobal(p.module, v, v.info)
 
-proc registerTraverseProc(p: BProc, v: PSym, traverseProc: Rope) =
-  if sfThread in v.flags:
-    appcg(p.module, p.module.preInitProc.procSec(cpsInit),
-      "$n\t#nimRegisterThreadLocalMarker($1);$n$n", [traverseProc])
-  else:
-    appcg(p.module, p.module.preInitProc.procSec(cpsInit),
-      "$n\t#nimRegisterGlobalMarker($1);$n$n", [traverseProc])
+  if traverseProc.len != 0 and not p.hcrOn:
+    if sfThread in v.flags:
+      appcg(p.module, p.module.preInitProc.procSec(cpsInit),
+        "$n\t#nimRegisterThreadLocalMarker($1);$n$n", [traverseProc])
+    else:
+      appcg(p.module, p.module.preInitProc.procSec(cpsInit),
+        "$n\t#nimRegisterGlobalMarker($1);$n$n", [traverseProc])
 
 proc isAssignedImmediately(conf: ConfigRef; n: PNode): bool {.inline.} =
   if n.kind == nkEmpty:
@@ -54,7 +55,9 @@ proc inExceptBlockLen(p: BProc): int =
 proc startBlockInternal(p: BProc): int {.discardable.} =
   inc(p.labels)
   result = p.blocks.len
-  setLen(p.blocks, result + 1)
+
+  p.blocks.add initBlock()
+
   p.blocks[result].id = p.labels
   p.blocks[result].nestedTryStmts = p.nestedTryStmts.len.int16
   p.blocks[result].nestedExceptStmts = p.inExceptBlockLen.int16
@@ -78,7 +81,7 @@ proc genVarTuple(p: BProc, n: PNode) =
 
   # check only the first son
   var forHcr = treatGlobalDifferentlyForHCR(p.module, n[0].sym)
-  let hcrCond = if forHcr: getTempName(p.module) else: nil
+  let hcrCond = if forHcr: getTempName(p.module) else: ""
   var hcrGlobals: seq[tuple[loc: TLoc, tp: Rope]]
   # determine if the tuple is constructed at top-level scope or inside of a block (if/while/block)
   let isGlobalInBlock = forHcr and p.blocks.len > 2
@@ -97,13 +100,10 @@ proc genVarTuple(p: BProc, n: PNode) =
     let vn = n[i]
     let v = vn.sym
     if sfCompileTime in v.flags: continue
-    var traverseProc: Rope
     if sfGlobal in v.flags:
-      assignGlobalVar(p, vn, nil)
+      assignGlobalVar(p, vn, "")
       genObjectInit(p, cpsInit, v.typ, v.loc, constructObj)
-      traverseProc = getTraverseProc(p, v)
-      if traverseProc != nil and not p.hcrOn:
-        registerTraverseProc(p, v, traverseProc)
+      registerTraverseProc(p, v)
     else:
       assignLocalVar(p, vn)
       initLocalVar(p, v, immediateAsgn=isAssignedImmediately(p.config, n[^1]))
@@ -115,7 +115,7 @@ proc genVarTuple(p: BProc, n: PNode) =
       field.r = "$1.$2" % [rdLoc(tup), mangleRecFieldName(p.module, t.n[i].sym)]
     putLocIntoDest(p, v.loc, field)
     if forHcr or isGlobalInBlock:
-      hcrGlobals.add((loc: v.loc, tp: if traverseProc == nil: ~"NULL" else: traverseProc))
+      hcrGlobals.add((loc: v.loc, tp: "NULL"))
 
   if forHcr:
     # end the block where the tuple gets initialized
@@ -145,12 +145,12 @@ proc loadInto(p: BProc, le, ri: PNode, a: var TLoc) {.inline.} =
     a.flags.incl(lfEnforceDeref)
     expr(p, ri, a)
 
-proc assignLabel(b: var TBlock): Rope {.inline.} =
+proc assignLabel(b: var TBlock; result: var Rope) {.inline.} =
   b.label = "LA" & b.id.rope
-  result = b.label
+  result.add b.label
 
-proc blockBody(b: var TBlock): Rope =
-  result = b.sections[cpsLocals]
+proc blockBody(b: var TBlock; result: var Rope) =
+  result.add b.sections[cpsLocals]
   if b.frameLen > 0:
     result.addf("FR_.len+=$1;$n", [b.frameLen.rope])
   result.add(b.sections[cpsInit])
@@ -159,7 +159,7 @@ proc blockBody(b: var TBlock): Rope =
 proc endBlock(p: BProc, blockEnd: Rope) =
   let topBlock = p.blocks.len-1
   # the block is merged into the parent block
-  p.blocks[topBlock-1].sections[cpsStmts].add(p.blocks[topBlock].blockBody)
+  p.blocks[topBlock].blockBody(p.blocks[topBlock-1].sections[cpsStmts])
   setLen(p.blocks, topBlock)
   # this is done after the block is popped so $n is
   # properly indented when pretty printing is enabled
@@ -171,7 +171,7 @@ proc endBlock(p: BProc) =
   var blockEnd: Rope
   if frameLen > 0:
     blockEnd.addf("FR_.len-=$1;$n", [frameLen.rope])
-  if p.blocks[topBlock].label != nil:
+  if p.blocks[topBlock].label.len != 0:
     blockEnd.addf("} $1: ;$n", [p.blocks[topBlock].label])
   else:
     blockEnd.addf("}$n", [])
@@ -279,17 +279,15 @@ proc genGotoVar(p: BProc; value: PNode) =
   else:
     lineF(p, cpsStmts, "goto NIMSTATE_$#;$n", [value.intVal.rope])
 
-proc genBracedInit(p: BProc, n: PNode; isConst: bool; optionalType: PType): Rope
+proc genBracedInit(p: BProc, n: PNode; isConst: bool; optionalType: PType; result: var Rope)
 
-proc potentialValueInit(p: BProc; v: PSym; value: PNode): Rope =
+proc potentialValueInit(p: BProc; v: PSym; value: PNode; result: var Rope) =
   if lfDynamicLib in v.loc.flags or sfThread in v.flags or p.hcrOn:
-    result = nil
+    discard "nothing to do"
   elif sfGlobal in v.flags and value != nil and isDeepConstExpr(value, p.module.compileToCpp) and
       p.withinLoop == 0 and not containsGarbageCollectedRef(v.typ):
     #echo "New code produced for ", v.name.s, " ", p.config $ value.info
-    result = genBracedInit(p, value, isConst = false, v.typ)
-  else:
-    result = nil
+    genBracedInit(p, value, isConst = false, v.typ, result)
 
 proc genSingleVar(p: BProc, v: PSym; vn, value: PNode) =
   if sfGoto in v.flags:
@@ -297,8 +295,8 @@ proc genSingleVar(p: BProc, v: PSym; vn, value: PNode) =
     genGotoVar(p, value)
     return
   var targetProc = p
-  var traverseProc: Rope
-  let valueAsRope = potentialValueInit(p, v, value)
+  var valueAsRope = ""
+  potentialValueInit(p, v, value, valueAsRope)
   if sfGlobal in v.flags:
     if v.flags * {sfImportc, sfExportc} == {sfImportc} and
         value.kind == nkEmpty and
@@ -314,7 +312,7 @@ proc genSingleVar(p: BProc, v: PSym; vn, value: PNode) =
     # That's why we are doing the construction inside the preInitProc.
     # genObjectInit relies on the C runtime's guarantees that
     # global variables will be initialized to zero.
-    if valueAsRope == nil:
+    if valueAsRope.len == 0:
       var loc = v.loc
 
       # When the native TLS is unavailable, a global thread-local variable needs
@@ -328,9 +326,7 @@ proc genSingleVar(p: BProc, v: PSym; vn, value: PNode) =
     # if sfImportc notin v.flags: constructLoc(p.module.preInitProc, v.loc)
     if sfExportc in v.flags and p.module.g.generatedHeader != nil:
       genVarPrototype(p.module.g.generatedHeader, vn)
-    traverseProc = getTraverseProc(p, v)
-    if traverseProc != nil and not p.hcrOn:
-      registerTraverseProc(p, v, traverseProc)
+    registerTraverseProc(p, v)
   else:
     let imm = isAssignedImmediately(p.config, value)
     if imm and p.module.compileToCpp and p.splitDecls == 0 and
@@ -343,14 +339,14 @@ proc genSingleVar(p: BProc, v: PSym; vn, value: PNode) =
       var tmp: TLoc
       if value.kind in nkCallKinds and value[0].kind == nkSym and
            sfConstructor in value[0].sym.flags:
-        var params: Rope
+        var params = newRopeAppender()
+        var argsCounter = 0
         let typ = skipTypes(value[0].typ, abstractInst)
         assert(typ.kind == tyProc)
         for i in 1..<value.len:
-          if params != nil: params.add(~", ")
           assert(typ.len == typ.n.len)
-          params.add(genOtherArg(p, value, i, typ))
-        if params == nil:
+          genOtherArg(p, value, i, typ, params, argsCounter)
+        if params.len == 0:
           lineF(p, cpsStmts, "$#;$n", [decl])
         else:
           lineF(p, cpsStmts, "$#($#);$n", [decl, params])
@@ -361,7 +357,7 @@ proc genSingleVar(p: BProc, v: PSym; vn, value: PNode) =
     assignLocalVar(p, vn)
     initLocalVar(p, v, imm)
 
-  if traverseProc == nil: traverseProc = ~"NULL"
+  let traverseProc = "NULL"
   # If the var is in a block (control flow like if/while or a block) in global scope just
   # register the so called "global" so it can be used later on. There is no need to close
   # and reopen of if (nim_hcr_do_init_) blocks because we are in one already anyway.
@@ -381,7 +377,7 @@ proc genSingleVar(p: BProc, v: PSym; vn, value: PNode) =
     lineCg(targetProc, cpsStmts, "if (hcrRegisterGlobal($3, \"$1\", sizeof($2), $4, (void**)&$1))$N",
            [v.loc.r, rdLoc(v.loc), getModuleDllPath(p.module, v), traverseProc])
     startBlock(targetProc)
-  if value.kind != nkEmpty and valueAsRope == nil:
+  if value.kind != nkEmpty and valueAsRope.len == 0:
     genLineDir(targetProc, vn)
     loadInto(targetProc, vn, value, v.loc)
   if forHcr:
@@ -560,7 +556,9 @@ proc genComputedGoto(p: BProc; n: PNode) =
         return
 
       let val = getOrdValue(it[j])
-      lineF(p, cpsStmts, "TMP$#_:$n", [intLiteral(toInt64(val)+id+1)])
+      var lit = newRopeAppender()
+      intLiteral(toInt64(val)+id+1, lit)
+      lineF(p, cpsStmts, "TMP$#_:$n", [lit])
 
     genStmts(p, it.lastSon)
 
@@ -614,8 +612,9 @@ proc genWhileStmt(p: BProc, t: PNode) =
       p.blocks[p.breakIdx].isLoop = true
       initLocExpr(p, t[0], a)
       if (t[0].kind != nkIntLit) or (t[0].intVal == 0):
-        let label = assignLabel(p.blocks[p.breakIdx])
-        lineF(p, cpsStmts, "if (!$1) goto $2;$n", [rdLoc(a), label])
+        lineF(p, cpsStmts, "if (!$1) goto ", [rdLoc(a)])
+        assignLabel(p.blocks[p.breakIdx], p.s(cpsStmts))
+        lineF(p, cpsStmts, ";$n", [])
       genStmts(p, loopBody)
 
       if optProfiler in p.options:
@@ -702,12 +701,12 @@ proc genBreakStmt(p: BProc, t: PNode) =
     while idx >= 0 and not p.blocks[idx].isLoop: dec idx
     if idx < 0 or not p.blocks[idx].isLoop:
       internalError(p.config, t.info, "no loop to break")
-  let label = assignLabel(p.blocks[idx])
+  p.blocks[idx].label = "LA" & p.blocks[idx].id.rope
   blockLeaveActions(p,
     p.nestedTryStmts.len - p.blocks[idx].nestedTryStmts,
     p.inExceptBlockLen - p.blocks[idx].nestedExceptStmts)
   genLineDir(p, t)
-  lineF(p, cpsStmts, "goto $1;$n", [label])
+  lineF(p, cpsStmts, "goto $1;$n", [p.blocks[idx].label])
 
 proc raiseExit(p: BProc) =
   assert p.config.exc == excGoto
@@ -729,21 +728,19 @@ proc finallyActions(p: BProc) =
     if finallyBlock != nil:
       genSimpleBlock(p, finallyBlock[0])
 
-proc raiseInstr(p: BProc): Rope =
+proc raiseInstr(p: BProc; result: var Rope) =
   if p.config.exc == excGoto:
     let L = p.nestedTryStmts.len
     if L == 0:
       p.flags.incl beforeRetNeeded
       # easy case, simply goto 'ret':
-      result = ropecg(p.module, "goto BeforeRet_;$n", [])
+      result.add ropecg(p.module, "goto BeforeRet_;$n", [])
     else:
       # raise inside an 'except' must go to the finally block,
       # raise outside an 'except' block must go to the 'except' list.
-      result = ropecg(p.module, "goto LA$1_;$n",
+      result.add ropecg(p.module, "goto LA$1_;$n",
         [p.nestedTryStmts[L-1].label])
       # + ord(p.nestedTryStmts[L-1].inExcept)])
-  else:
-    result = nil
 
 proc genRaiseStmt(p: BProc, t: PNode) =
   if t[0].kind != nkEmpty:
@@ -772,12 +769,10 @@ proc genRaiseStmt(p: BProc, t: PNode) =
     genLineDir(p, t)
     # reraise the last exception:
     if p.config.exc == excCpp:
-      line(p, cpsStmts, ~"throw;$n")
+      line(p, cpsStmts, "throw;\n")
     else:
       linefmt(p, cpsStmts, "#reraiseException();$n", [])
-  let gotoInstr = raiseInstr(p)
-  if gotoInstr != nil:
-    line(p, cpsStmts, gotoInstr)
+  raiseInstr(p, p.s(cpsStmts))
 
 template genCaseGenericBranch(p: BProc, b: PNode, e: TLoc,
                           rangeFormat, eqFormat: FormatStr, labl: TLabel) =
@@ -885,9 +880,11 @@ proc genStringCase(p: BProc, t: PNode, stringKind: TTypeKind, d: var TLoc) =
       linefmt(p, cpsStmts, "switch (#hashString($1) & $2) {$n",
               [rdLoc(a), bitMask])
     for j in 0..high(branches):
-      if branches[j] != nil:
+      if branches[j] != "":
+        var lit = newRopeAppender()
+        intLiteral(j, lit)
         lineF(p, cpsStmts, "case $1: $n$2break;$n",
-             [intLiteral(j), branches[j]])
+             [lit, branches[j]])
     lineF(p, cpsStmts, "}$n", []) # else statement:
     if t[^1].kind != nkOfBranch:
       lineF(p, cpsStmts, "goto LA$1_;$n", [rope(p.labels)])
@@ -921,16 +918,22 @@ proc genCaseRange(p: BProc, branch: PNode) =
   for j in 0..<branch.len-1:
     if branch[j].kind == nkRange:
       if hasSwitchRange in CC[p.config.cCompiler].props:
-        lineF(p, cpsStmts, "case $1 ... $2:$n", [
-            genLiteral(p, branch[j][0]),
-            genLiteral(p, branch[j][1])])
+        var litA = newRopeAppender()
+        var litB = newRopeAppender()
+        genLiteral(p, branch[j][0], litA)
+        genLiteral(p, branch[j][1], litB)
+        lineF(p, cpsStmts, "case $1 ... $2:$n", [litA, litB])
       else:
         var v = copyNode(branch[j][0])
         while v.intVal <= branch[j][1].intVal:
-          lineF(p, cpsStmts, "case $1:$n", [genLiteral(p, v)])
+          var litA = newRopeAppender()
+          genLiteral(p, v, litA)
+          lineF(p, cpsStmts, "case $1:$n", [litA])
           inc(v.intVal)
     else:
-      lineF(p, cpsStmts, "case $1:$n", [genLiteral(p, branch[j])])
+      var litA = newRopeAppender()
+      genLiteral(p, branch[j], litA)
+      lineF(p, cpsStmts, "case $1:$n", [litA])
 
 proc genOrdinalCase(p: BProc, n: PNode, d: var TLoc) =
   # analyse 'case' statement:
@@ -942,7 +945,7 @@ proc genOrdinalCase(p: BProc, n: PNode, d: var TLoc) =
   var lend = if splitPoint > 0: genIfForCaseUntil(p, n, d,
                     rangeFormat = "if ($1 >= $2 && $1 <= $3) goto $4;$n",
                     eqFormat = "if ($1 == $2) goto $3;$n",
-                    splitPoint, a) else: nil
+                    splitPoint, a) else: ""
 
   # generate switch part (might be empty):
   if splitPoint+1 < n.len:
@@ -963,7 +966,7 @@ proc genOrdinalCase(p: BProc, n: PNode, d: var TLoc) =
     if (hasAssume in CC[p.config.cCompiler].props) and not hasDefault:
       lineF(p, cpsStmts, "default: __assume(0);$n", [])
     lineF(p, cpsStmts, "}$n", [])
-  if lend != nil: fixLabel(p, lend)
+  if lend != "": fixLabel(p, lend)
 
 proc genCase(p: BProc, t: PNode, d: var TLoc) =
   genLineDir(p, t)
@@ -1064,7 +1067,7 @@ proc genTryCpp(p: BProc, t: PNode, d: var TLoc) =
       linefmt(p, cpsStmts, "#popCurrentException();$n", [])
       endBlock(p)
     else:
-      var orExpr = Rope(nil)
+      var orExpr = newRopeAppender()
       var exvar = PNode(nil)
       for j in 0..<t[i].len - 1:
         var typeNode = t[i][j]
@@ -1075,7 +1078,7 @@ proc genTryCpp(p: BProc, t: PNode, d: var TLoc) =
         if isImportedException(typeNode.typ, p.config):
           hasImportedCppExceptions = true
         else:
-          if orExpr != nil: orExpr.add("||")
+          if orExpr.len != 0: orExpr.add("||")
           let checkFor = if optTinyRtti in p.config.globalOptions:
             genTypeInfo2Name(p.module, typeNode.typ)
           else:
@@ -1083,14 +1086,15 @@ proc genTryCpp(p: BProc, t: PNode, d: var TLoc) =
           let memberName = if p.module.compileToCpp: "m_type" else: "Sup.m_type"
           appcg(p.module, orExpr, "#isObj(#nimBorrowCurrentException()->$1, $2)", [memberName, checkFor])
 
-      if orExpr != nil:
+      if orExpr.len != 0:
         if hasIf:
           startBlock(p, "else if ($1) {$n", [orExpr])
         else:
           startBlock(p, "if ($1) {$n", [orExpr])
           hasIf = true
         if exvar != nil:
-          fillLoc(exvar.sym.loc, locTemp, exvar, mangleLocalName(p, exvar.sym), OnStack)
+          fillLocalName(p, exvar.sym)
+          fillLoc(exvar.sym.loc, locTemp, exvar, OnStack)
           linefmt(p, cpsStmts, "$1 $2 = T$3_;$n", [getTypeDesc(p.module, exvar.sym.typ),
             rdLoc(exvar.sym.loc), rope(etmp+1)])
         # we handled the error:
@@ -1131,7 +1135,8 @@ proc genTryCpp(p: BProc, t: PNode, d: var TLoc) =
             typeNode = t[i][j][1]
             if isImportedException(typeNode.typ, p.config):
               let exvar = t[i][j][2] # ex1 in `except ExceptType as ex1:`
-              fillLoc(exvar.sym.loc, locTemp, exvar, mangleLocalName(p, exvar.sym), OnStack)
+              fillLocalName(p, exvar.sym)
+              fillLoc(exvar.sym.loc, locTemp, exvar, OnStack)
               startBlock(p, "catch ($1& $2) {$n", getTypeDesc(p.module, typeNode.typ), rdLoc(exvar.sym.loc))
               genExceptBranchBody(t[i][^1])  # exception handler body will duplicated for every type
               endBlock(p)
@@ -1184,7 +1189,7 @@ proc genTryCppOld(p: BProc, t: PNode, d: var TLoc) =
   if not isEmptyType(t.typ) and d.k == locNone:
     getTemp(p, t.typ, d)
   genLineDir(p, t)
-  discard cgsym(p.module, "popCurrentExceptionEx")
+  cgsym(p.module, "popCurrentExceptionEx")
   let fin = if t[^1].kind == nkFinally: t[^1] else: nil
   p.nestedTryStmts.add((fin, false, 0.Natural))
   startBlock(p, "try {$n")
@@ -1210,7 +1215,8 @@ proc genTryCppOld(p: BProc, t: PNode, d: var TLoc) =
       for j in 0..<t[i].len-1:
         if t[i][j].isInfixAs():
           let exvar = t[i][j][2] # ex1 in `except ExceptType as ex1:`
-          fillLoc(exvar.sym.loc, locTemp, exvar, mangleLocalName(p, exvar.sym), OnUnknown)
+          fillLocalName(p, exvar.sym)
+          fillLoc(exvar.sym.loc, locTemp, exvar, OnUnknown)
           startBlock(p, "catch ($1& $2) {$n", getTypeDesc(p.module, t[i][j][1].typ), rdLoc(exvar.sym.loc))
         else:
           startBlock(p, "catch ($1&) {$n", getTypeDesc(p.module, t[i][j].typ))
@@ -1225,7 +1231,7 @@ proc genTryCppOld(p: BProc, t: PNode, d: var TLoc) =
       # finally requires catch all presence
       startBlock(p, "catch (...) {$n")
       genStmts(p, t[^1][0])
-      line(p, cpsStmts, ~"throw;$n")
+      line(p, cpsStmts, "throw;\n")
       endBlock(p)
 
     genSimpleBlock(p, t[^1][0])
@@ -1287,10 +1293,10 @@ proc genTryGoto(p: BProc; t: PNode; d: var TLoc) =
       linefmt(p, cpsStmts, "*nimErr_ = NIM_FALSE;$n", [])
       expr(p, t[i][0], d)
     else:
-      var orExpr: Rope = nil
+      var orExpr = newRopeAppender()
       for j in 0..<t[i].len - 1:
         assert(t[i][j].kind == nkType)
-        if orExpr != nil: orExpr.add("||")
+        if orExpr.len != 0: orExpr.add("||")
         let checkFor = if optTinyRtti in p.config.globalOptions:
           genTypeInfo2Name(p.module, t[i][j].typ)
         else:
@@ -1372,7 +1378,7 @@ proc genTrySetjmp(p: BProc, t: PNode, d: var TLoc) =
   else:
     p.flags.incl noSafePoints
   genLineDir(p, t)
-  discard cgsym(p.module, "Exception")
+  cgsym(p.module, "Exception")
   var safePoint: Rope
   if not quirkyExceptions:
     safePoint = getTempName(p.module)
@@ -1389,7 +1395,7 @@ proc genTrySetjmp(p: BProc, t: PNode, d: var TLoc) =
         if isDefined(p.config, "vcc") or isDefined(p.config, "clangcl"):
           # For the vcc compiler, use `setjmp()` with one argument.
           # See https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/setjmp?view=msvc-170
-          linefmt(p, cpsStmts, "$1.status = setjmp($1.context);$n", [safePoint])        
+          linefmt(p, cpsStmts, "$1.status = setjmp($1.context);$n", [safePoint])
         else:
           # The Windows `_setjmp()` takes two arguments, with the second being an
           # undocumented buffer used by the SEH mechanism for stack unwinding.
@@ -1431,10 +1437,10 @@ proc genTrySetjmp(p: BProc, t: PNode, d: var TLoc) =
       linefmt(p, cpsStmts, "#popCurrentException();$n", [])
       endBlock(p)
     else:
-      var orExpr: Rope = nil
+      var orExpr = newRopeAppender()
       for j in 0..<t[i].len - 1:
         assert(t[i][j].kind == nkType)
-        if orExpr != nil: orExpr.add("||")
+        if orExpr.len != 0: orExpr.add("||")
         let checkFor = if optTinyRtti in p.config.globalOptions:
           genTypeInfo2Name(p.module, t[i][j].typ)
         else:
@@ -1466,7 +1472,7 @@ proc genTrySetjmp(p: BProc, t: PNode, d: var TLoc) =
   if not quirkyExceptions:
     linefmt(p, cpsStmts, "if ($1.status != 0) #reraiseException();$n", [safePoint])
 
-proc genAsmOrEmitStmt(p: BProc, t: PNode, isAsmStmt=false): Rope =
+proc genAsmOrEmitStmt(p: BProc, t: PNode, isAsmStmt=false; result: var Rope) =
   var res = ""
   for it in t.sons:
     case it.kind
@@ -1482,13 +1488,8 @@ proc genAsmOrEmitStmt(p: BProc, t: PNode, isAsmStmt=false): Rope =
         res.add($getTypeDesc(p.module, sym.typ))
       else:
         discard getTypeDesc(p.module, skipTypes(sym.typ, abstractPtrs))
-        var r = sym.loc.r
-        if r == nil:
-          # if no name has already been given,
-          # it doesn't matter much:
-          r = mangleName(p.module, sym)
-          sym.loc.r = r       # but be consequent!
-        res.add($r)
+        fillBackendName(p.module, sym)
+        res.add($sym.loc.r)
     of nkTypeOfExpr:
       res.add($getTypeDesc(p.module, it.typ))
     else:
@@ -1513,12 +1514,13 @@ proc genAsmOrEmitStmt(p: BProc, t: PNode, isAsmStmt=false): Rope =
           result.add("\\n\"\n")
   else:
     res.add("\L")
-    result = res.rope
+    result.add res.rope
 
 proc genAsmStmt(p: BProc, t: PNode) =
   assert(t.kind == nkAsmStmt)
   genLineDir(p, t)
-  var s = genAsmOrEmitStmt(p, t, isAsmStmt=true)
+  var s = newRopeAppender()
+  genAsmOrEmitStmt(p, t, isAsmStmt=true, s)
   # see bug #2362, "top level asm statements" seem to be a mis-feature
   # but even if we don't do this, the example in #2362 cannot possibly
   # work:
@@ -1526,7 +1528,8 @@ proc genAsmStmt(p: BProc, t: PNode) =
     # top level asm statement?
     p.module.s[cfsProcHeaders].add runtimeFormat(CC[p.config.cCompiler].asmStmtFrmt, [s])
   else:
-    p.s(cpsStmts).add indentLine(p, runtimeFormat(CC[p.config.cCompiler].asmStmtFrmt, [s]))
+    addIndent p, p.s(cpsStmts)
+    p.s(cpsStmts).add runtimeFormat(CC[p.config.cCompiler].asmStmtFrmt, [s])
 
 proc determineSection(n: PNode): TCFileSection =
   result = cfsProcHeaders
@@ -1537,7 +1540,8 @@ proc determineSection(n: PNode): TCFileSection =
     elif sec.startsWith("/*INCLUDESECTION*/"): result = cfsHeaders
 
 proc genEmit(p: BProc, t: PNode) =
-  var s = genAsmOrEmitStmt(p, t[1])
+  var s = newRopeAppender()
+  genAsmOrEmitStmt(p, t[1], false, s)
   if p.prc == nil:
     # top level emit pragma?
     let section = determineSection(t[1])
@@ -1562,10 +1566,12 @@ proc genDiscriminantCheck(p: BProc, a, tmp: TLoc, objtype: PType,
   if not containsOrIncl(p.module.declaredThings, field.id):
     appcg(p.module, cfsVars, "extern $1",
           [discriminatorTableDecl(p.module, t, field)])
+  var lit = newRopeAppender()
+  intLiteral(toInt64(lengthOrd(p.config, field.typ))+1, lit)
   lineCg(p, cpsStmts,
         "#FieldDiscriminantCheck((NI)(NU)($1), (NI)(NU)($2), $3, $4);$n",
         [rdLoc(a), rdLoc(tmp), discriminatorTableName(p.module, t, field),
-         intLiteral(toInt64(lengthOrd(p.config, field.typ))+1)])
+         lit])
 
 when false:
   proc genCaseObjDiscMapping(p: BProc, e: PNode, t: PType, field: PSym; d: var TLoc) =
diff --git a/compiler/ccgthreadvars.nim b/compiler/ccgthreadvars.nim
index fbe8bce9ed577..abf830b577dd8 100644
--- a/compiler/ccgthreadvars.nim
+++ b/compiler/ccgthreadvars.nim
@@ -44,13 +44,13 @@ proc declareThreadVar(m: BModule, s: PSym, isExtern: bool) =
     m.s[cfsVars].addf(" $1;$n", [s.loc.r])
 
 proc generateThreadLocalStorage(m: BModule) =
-  if m.g.nimtv != nil and (usesThreadVars in m.flags or sfMainModule in m.module.flags):
+  if m.g.nimtv != "" and (usesThreadVars in m.flags or sfMainModule in m.module.flags):
     for t in items(m.g.nimtvDeps): discard getTypeDesc(m, t)
     finishTypeDescriptions(m)
     m.s[cfsSeqTypes].addf("typedef struct {$1} NimThreadVars;$n", [m.g.nimtv])
 
 proc generateThreadVarsSize(m: BModule) =
-  if m.g.nimtv != nil:
+  if m.g.nimtv != "":
     let externc = if m.config.backend == backendCpp or
                        sfCompileToCpp in m.module.flags: "extern \"C\" "
                   else: ""
diff --git a/compiler/ccgtrav.nim b/compiler/ccgtrav.nim
index 29b93e5308bad..96f5869b00606 100644
--- a/compiler/ccgtrav.nim
+++ b/compiler/ccgtrav.nim
@@ -34,7 +34,7 @@ proc genTraverseProc(c: TTraversalClosure, accessor: Rope, n: PNode;
     if (n[0].kind != nkSym): internalError(c.p.config, n.info, "genTraverseProc")
     var p = c.p
     let disc = n[0].sym
-    if disc.loc.r == nil: fillObjectFields(c.p.module, typ)
+    if disc.loc.r == "": fillObjectFields(c.p.module, typ)
     if disc.loc.t == nil:
       internalError(c.p.config, n.info, "genTraverseProc()")
     lineF(p, cpsStmts, "switch ($1.$2) {$n", [accessor, disc.loc.r])
@@ -51,7 +51,7 @@ proc genTraverseProc(c: TTraversalClosure, accessor: Rope, n: PNode;
   of nkSym:
     let field = n.sym
     if field.typ.kind == tyVoid: return
-    if field.loc.r == nil: fillObjectFields(c.p.module, typ)
+    if field.loc.r == "": fillObjectFields(c.p.module, typ)
     if field.loc.t == nil:
       internalError(c.p.config, n.info, "genTraverseProc()")
     genTraverseProc(c, "$1.$2" % [accessor, field.loc.r], field.loc.t)
@@ -76,7 +76,8 @@ proc genTraverseProc(c: TTraversalClosure, accessor: Rope, typ: PType) =
     let arraySize = lengthOrd(c.p.config, typ[0])
     var i: TLoc
     getTemp(p, getSysType(c.p.module.g.graph, unknownLineInfo, tyInt), i)
-    let oldCode = p.s(cpsStmts)
+    var oldCode = p.s(cpsStmts)
+    freeze oldCode
     linefmt(p, cpsStmts, "for ($1 = 0; $1 < $2; $1++) {$n",
             [i.r, arraySize])
     let oldLen = p.s(cpsStmts).len
@@ -120,7 +121,8 @@ proc genTraverseProcSeq(c: TTraversalClosure, accessor: Rope, typ: PType) =
   assert typ.kind == tySequence
   var i: TLoc
   getTemp(p, getSysType(c.p.module.g.graph, unknownLineInfo, tyInt), i)
-  let oldCode = p.s(cpsStmts)
+  var oldCode = p.s(cpsStmts)
+  freeze oldCode
   var a: TLoc
   a.r = accessor
 
diff --git a/compiler/ccgtypes.nim b/compiler/ccgtypes.nim
index 654e266ba77cb..1aa8292bdb175 100644
--- a/compiler/ccgtypes.nim
+++ b/compiler/ccgtypes.nim
@@ -13,8 +13,6 @@
 
 import sighashes, modulegraphs
 
-proc genProcHeader(m: BModule, prc: PSym, asPtr: bool = false): Rope
-
 proc isKeyword(w: PIdent): bool =
   # Nim and C++ share some keywords
   # it's more efficient to test the whole Nim keywords range
@@ -35,10 +33,9 @@ proc mangleField(m: BModule; name: PIdent): string =
   if isKeyword(name):
     result.add "_0"
 
-proc mangleName(m: BModule; s: PSym): Rope =
-  result = s.loc.r
-  if result == nil:
-    result = s.name.s.mangle.rope
+proc fillBackendName(m: BModule; s: PSym) =
+  if s.loc.r == "":
+    var result = s.name.s.mangle.rope
     result.add "__"
     result.add m.g.graph.ifaces[s.itemId.module].uniqueName
     result.add "_"
@@ -49,12 +46,11 @@ proc mangleName(m: BModule; s: PSym): Rope =
     s.loc.r = result
     writeMangledName(m.ndi, s, m.config)
 
-proc mangleParamName(m: BModule; s: PSym): Rope =
+proc fillParamName(m: BModule; s: PSym) =
   ## we cannot use 'sigConflicts' here since we have a BModule, not a BProc.
   ## Fortunately C's scoping rules are sane enough so that that doesn't
   ## cause any trouble.
-  result = s.loc.r
-  if result == nil:
+  if s.loc.r == "":
     var res = s.name.s.mangle
     # Take into account if HCR is on because of the following scenario:
     #   if a module gets imported and it has some more importc symbols in it,
@@ -74,20 +70,16 @@ proc mangleParamName(m: BModule; s: PSym): Rope =
     # executable file for the main module, which is running (or both!) -> error.
     if m.hcrOn or isKeyword(s.name) or m.g.config.cppDefines.contains(res):
       res.add "_0"
-    result = res.rope
-    s.loc.r = result
+    s.loc.r = res.rope
     writeMangledName(m.ndi, s, m.config)
 
-proc mangleLocalName(p: BProc; s: PSym): Rope =
+proc fillLocalName(p: BProc; s: PSym) =
   assert s.kind in skLocalVars+{skTemp}
   #assert sfGlobal notin s.flags
-  result = s.loc.r
-  if result == nil:
+  if s.loc.r == "":
     var key = s.name.s.mangle
-    when not defined(nimSeqsV2):
-      shallow(key)
     let counter = p.sigConflicts.getOrDefault(key)
-    result = key.rope
+    var result = key.rope
     if s.kind == skTemp:
       # speed up conflict search for temps (these are quite common):
       if counter != 0: result.add "_" & rope(counter+1)
@@ -103,8 +95,6 @@ proc scopeMangledParam(p: BProc; param: PSym) =
   ## generate unique identifiers reliably (consider that ``var a = a`` is
   ## even an idiom in Nim).
   var key = param.name.s.mangle
-  when not defined(nimSeqsV2):
-    shallow(key)
   p.sigConflicts.inc(key)
 
 const
@@ -112,13 +102,12 @@ const
                           tyDistinct, tyRange, tyStatic, tyAlias, tySink,
                           tyInferred, tyOwned}
 
-proc typeName(typ: PType): Rope =
+proc typeName(typ: PType; result: var Rope) =
   let typ = typ.skipTypes(irrelevantForBackend)
-  result =
-    if typ.sym != nil and typ.kind in {tyObject, tyEnum}:
-      rope($typ.kind & '_' & typ.sym.name.s.mangle)
-    else:
-      rope($typ.kind)
+  result.add $typ.kind
+  if typ.sym != nil and typ.kind in {tyObject, tyEnum}:
+    result.add "_"
+    result.add typ.sym.name.s.mangle
 
 proc getTypeName(m: BModule; typ: PType; sig: SigHash): Rope =
   var t = typ
@@ -131,14 +120,17 @@ proc getTypeName(m: BModule; typ: PType; sig: SigHash): Rope =
     else:
       break
   let typ = if typ.kind in {tyAlias, tySink, tyOwned}: typ.lastSon else: typ
-  if typ.loc.r == nil:
-    typ.loc.r = typ.typeName & $sig
+  if typ.loc.r == "":
+    typ.typeName(typ.loc.r)
+    typ.loc.r.add $sig
   else:
     when defined(debugSigHashes):
       # check consistency:
-      assert($typ.loc.r == $(typ.typeName & $sig))
+      var tn = newRopeAppender()
+      typ.typeName(tn)
+      assert($typ.loc.r == $(tn & $sig))
   result = typ.loc.r
-  if result == nil: internalError(m.config, "getTypeName: " & $typ.kind)
+  if result == "": internalError(m.config, "getTypeName: " & $typ.kind)
 
 proc mapSetType(conf: ConfigRef; typ: PType): TCTypeKind =
   case int(getSize(conf, typ))
@@ -266,7 +258,7 @@ proc addAbiCheck(m: BModule, t: PType, name: Rope) =
 
 
 proc fillResult(conf: ConfigRef; param: PNode, proctype: PType) =
-  fillLoc(param.sym.loc, locParam, param, ~"Result",
+  fillLoc(param.sym.loc, locParam, param, "Result",
           OnStack)
   let t = param.sym.typ
   if mapReturnType(conf, t) != ctArray and isInvalidReturnType(conf, proctype):
@@ -292,11 +284,11 @@ proc getSimpleTypeDesc(m: BModule, typ: PType): Rope =
   of tyString:
     case detectStrVersion(m)
     of 2:
-      discard cgsym(m, "NimStrPayload")
-      discard cgsym(m, "NimStringV2")
+      cgsym(m, "NimStrPayload")
+      cgsym(m, "NimStringV2")
       result = typeNameOrLiteral(m, typ, "NimStringV2")
     else:
-      discard cgsym(m, "NimStringDesc")
+      cgsym(m, "NimStringDesc")
       result = typeNameOrLiteral(m, typ, "NimStringDesc*")
   of tyCstring: result = typeNameOrLiteral(m, typ, "NCSTRING")
   of tyBool: result = typeNameOrLiteral(m, typ, "NIM_BOOL")
@@ -310,11 +302,11 @@ proc getSimpleTypeDesc(m: BModule, typ: PType): Rope =
     else: internalError(m.config, "tyStatic for getSimpleTypeDesc")
   of tyGenericInst, tyAlias, tySink, tyOwned:
     result = getSimpleTypeDesc(m, lastSon typ)
-  else: result = nil
+  else: result = ""
 
-  if result != nil and typ.isImportedType():
+  if result != "" and typ.isImportedType():
     let sig = hashType typ
-    if cacheGetType(m.typeCache, sig) == nil:
+    if cacheGetType(m.typeCache, sig) == "":
       m.typeCache[sig] = result
 
 proc pushType(m: BModule, typ: PType) =
@@ -327,7 +319,7 @@ proc getTypePre(m: BModule, typ: PType; sig: SigHash): Rope =
   if typ == nil: result = rope("void")
   else:
     result = getSimpleTypeDesc(m, typ)
-    if result == nil: result = cacheGetType(m.typeCache, sig)
+    if result == "": result = cacheGetType(m.typeCache, sig)
 
 proc structOrUnion(t: PType): Rope =
   let cachedUnion = rope("union")
@@ -348,9 +340,9 @@ proc seqStar(m: BModule): string =
 
 proc getTypeForward(m: BModule, typ: PType; sig: SigHash): Rope =
   result = cacheGetType(m.forwTypeCache, sig)
-  if result != nil: return
+  if result != "": return
   result = getTypePre(m, typ, sig)
-  if result != nil: return
+  if result != "": return
   let concrete = typ.skipTypes(abstractInst)
   case concrete.kind
   of tySequence, tyTuple, tyObject:
@@ -382,7 +374,7 @@ proc getTypeDescWeak(m: BModule; t: PType; check: var IntSet; kind: TSymKind): R
         internalError(m.config, "cannot map the empty seq type to a C type")
 
       result = cacheGetType(m.forwTypeCache, sig)
-      if result == nil:
+      if result == "":
         result = getTypeName(m, t, sig)
         if not isImportedType(t):
           m.forwTypeCache[sig] = result
@@ -390,7 +382,7 @@ proc getTypeDescWeak(m: BModule; t: PType; check: var IntSet; kind: TSymKind): R
           let payload = result & "_Content"
           addForwardStructFormat(m, rope"struct", payload)
 
-      if cacheGetType(m.typeCache, sig) == nil:
+      if cacheGetType(m.typeCache, sig) == "":
         m.typeCache[sig] = result
         #echo "adding ", sig, " ", typeToString(t), " ", m.module.name.s
         appcg(m, m.s[cfsTypes],
@@ -411,7 +403,7 @@ proc getSeqPayloadType(m: BModule; t: PType): Rope =
 proc seqV2ContentType(m: BModule; t: PType; check: var IntSet) =
   let sig = hashType(t)
   let result = cacheGetType(m.typeCache, sig)
-  if result == nil:
+  if result == "":
     discard getTypeDescAux(m, t, check, skVar)
   else:
     # little hack for now to prevent multiple definitions of the same
@@ -433,30 +425,31 @@ proc paramStorageLoc(param: PSym): TStorageLoc =
 proc genProcParams(m: BModule, t: PType, rettype, params: var Rope,
                    check: var IntSet, declareEnvironment=true;
                    weakDep=false) =
-  params = nil
+  params = ""
   if t[0] == nil or isInvalidReturnType(m.config, t):
-    rettype = ~"void"
+    rettype = "void"
   else:
     rettype = getTypeDescAux(m, t[0], check, skResult)
   for i in 1..<t.n.len:
     if t.n[i].kind != nkSym: internalError(m.config, t.n.info, "genProcParams")
     var param = t.n[i].sym
     if isCompileTimeOnly(param.typ): continue
-    if params != nil: params.add(~", ")
-    fillLoc(param.loc, locParam, t.n[i], mangleParamName(m, param),
+    if params != "": params.add(", ")
+    fillParamName(m, param)
+    fillLoc(param.loc, locParam, t.n[i],
             param.paramStorageLoc)
     if ccgIntroducedPtr(m.config, param, t[0]):
       params.add(getTypeDescWeak(m, param.typ, check, skParam))
-      params.add(~"*")
+      params.add("*")
       incl(param.loc.flags, lfIndirect)
       param.loc.storage = OnUnknown
     elif weakDep:
       params.add(getTypeDescWeak(m, param.typ, check, skParam))
     else:
       params.add(getTypeDescAux(m, param.typ, check, skParam))
-    params.add(~" ")
+    params.add(" ")
     if sfNoalias in param.flags:
-      params.add(~"NIM_NOALIAS ")
+      params.add("NIM_NOALIAS ")
     params.add(param.loc.r)
     # declare the len field for open arrays:
     var arr = param.typ.skipTypes({tyGenericInst})
@@ -471,7 +464,7 @@ proc genProcParams(m: BModule, t: PType, rettype, params: var Rope,
       arr = arr[0].skipTypes({tySink})
   if t[0] != nil and isInvalidReturnType(m.config, t):
     var arr = t[0]
-    if params != nil: params.add(", ")
+    if params != "": params.add(", ")
     if mapReturnType(m.config, t[0]) != ctArray:
       if isHeaderFile in m.flags:
         # still generates types for `--header`
@@ -484,12 +477,12 @@ proc genProcParams(m: BModule, t: PType, rettype, params: var Rope,
       params.add(getTypeDescAux(m, arr, check, skResult))
     params.addf(" Result", [])
   if t.callConv == ccClosure and declareEnvironment:
-    if params != nil: params.add(", ")
+    if params != "": params.add(", ")
     params.add("void* ClE_0")
   if tfVarargs in t.flags:
-    if params != nil: params.add(", ")
+    if params != "": params.add(", ")
     params.add("...")
-  if params == nil: params.add("void)")
+  if params == "": params.add("void)")
   else: params.add(")")
   params = "(" & params
 
@@ -498,30 +491,30 @@ proc mangleRecFieldName(m: BModule; field: PSym): Rope =
     result = field.loc.r
   else:
     result = rope(mangleField(m, field.name))
-  if result == nil: internalError(m.config, field.info, "mangleRecFieldName")
+  if result == "": internalError(m.config, field.info, "mangleRecFieldName")
 
 proc genRecordFieldsAux(m: BModule, n: PNode,
                         rectype: PType,
-                        check: var IntSet, unionPrefix = ""): Rope =
-  result = nil
+                        check: var IntSet; result: var Rope; unionPrefix = "") =
   case n.kind
   of nkRecList:
     for i in 0..<n.len:
-      result.add(genRecordFieldsAux(m, n[i], rectype, check, unionPrefix))
+      genRecordFieldsAux(m, n[i], rectype, check, result, unionPrefix)
   of nkRecCase:
     if n[0].kind != nkSym: internalError(m.config, n.info, "genRecordFieldsAux")
-    result.add(genRecordFieldsAux(m, n[0], rectype, check, unionPrefix))
+    genRecordFieldsAux(m, n[0], rectype, check, result, unionPrefix)
     # prefix mangled name with "_U" to avoid clashes with other field names,
     # since identifiers are not allowed to start with '_'
-    var unionBody: Rope = nil
+    var unionBody: Rope = ""
     for i in 1..<n.len:
       case n[i].kind
       of nkOfBranch, nkElse:
         let k = lastSon(n[i])
         if k.kind != nkSym:
           let structName = "_" & mangleRecFieldName(m, n[0].sym) & "_" & $i
-          let a = genRecordFieldsAux(m, k, rectype, check, unionPrefix & $structName & ".")
-          if a != nil:
+          var a = newRopeAppender()
+          genRecordFieldsAux(m, k, rectype, check, a, unionPrefix & $structName & ".")
+          if a != "":
             if tfPacked notin rectype.flags:
               unionBody.add("struct {")
             else:
@@ -534,9 +527,9 @@ proc genRecordFieldsAux(m: BModule, n: PNode,
             if tfPacked in rectype.flags and hasAttribute notin CC[m.config.cCompiler].props:
               unionBody.addf("#pragma pack(pop)$n", [])
         else:
-          unionBody.add(genRecordFieldsAux(m, k, rectype, check, unionPrefix))
+          genRecordFieldsAux(m, k, rectype, check, unionBody, unionPrefix)
       else: internalError(m.config, "genRecordFieldsAux(record case branch)")
-    if unionBody != nil:
+    if unionBody != "":
       result.addf("union{$n$1};$n", [unionBody])
   of nkSym:
     let field = n.sym
@@ -550,7 +543,7 @@ proc genRecordFieldsAux(m: BModule, n: PNode,
     # have to recurse via 'getTypeDescAux'. And not doing so prevents problems
     # with heavily templatized C++ code:
     if not isImportedCppType(rectype):
-      let noAlias = if sfNoalias in field.flags: ~" NIM_NOALIAS" else: nil
+      let noAlias = if sfNoalias in field.flags: " NIM_NOALIAS" else: ""
 
       let fieldType = field.loc.lode.typ.skipTypes(abstractInst)
       if fieldType.kind == tyUncheckedArray:
@@ -568,7 +561,8 @@ proc genRecordFieldsAux(m: BModule, n: PNode,
   else: internalError(m.config, n.info, "genRecordFieldsAux()")
 
 proc getRecordFields(m: BModule, typ: PType, check: var IntSet): Rope =
-  result = genRecordFieldsAux(m, typ.n, typ, check)
+  result = newRopeAppender()
+  genRecordFieldsAux(m, typ.n, typ, check, result)
 
 proc fillObjectFields*(m: BModule; typ: PType) =
   # sometimes generic objects are not consistently merged. We patch over
@@ -625,7 +619,7 @@ proc getRecordDesc(m: BModule, typ: PType, name: Rope,
     result.addf(" {$n", [name])
 
   let desc = getRecordFields(m, typ, check)
-  if desc == nil and not hasField:
+  if desc == "" and not hasField:
     result.addf("char dummy;$n", [])
   else:
     result.add(desc)
@@ -636,11 +630,11 @@ proc getRecordDesc(m: BModule, typ: PType, name: Rope,
 proc getTupleDesc(m: BModule, typ: PType, name: Rope,
                   check: var IntSet): Rope =
   result = "$1 $2 {$n" % [structOrUnion(typ), name]
-  var desc: Rope = nil
+  var desc: Rope = ""
   for i in 0..<typ.len:
     desc.addf("$1 Field$2;$n",
          [getTypeDescAux(m, typ[i], check, skField), rope(i)])
-  if desc == nil: result.add("char dummy;\L")
+  if desc == "": result.add("char dummy;\L")
   else: result.add(desc)
   result.add("};\L")
 
@@ -679,7 +673,7 @@ proc getOpenArrayDesc(m: BModule, t: PType, check: var IntSet; kind: TSymKind):
     result = getTypeDescWeak(m, t[0], check, kind) & "*"
   else:
     result = cacheGetType(m.typeCache, sig)
-    if result == nil:
+    if result == "":
       result = getTypeName(m, t, sig)
       m.typeCache[sig] = result
       let elemType = getTypeDescWeak(m, t[0], check, kind)
@@ -705,7 +699,7 @@ proc getTypeDescAux(m: BModule, origTyp: PType, check: var IntSet; kind: TSymKin
       addAbiCheck(m, t, result)
 
   result = getTypePre(m, t, sig)
-  if result != nil and t.kind != tyOpenArray:
+  if result != "" and t.kind != tyOpenArray:
     excl(check, t.id)
     return
   case t.kind
@@ -748,7 +742,7 @@ proc getTypeDescAux(m: BModule, origTyp: PType, check: var IntSet; kind: TSymKin
     result = getOpenArrayDesc(m, t, check, kind)
   of tyEnum:
     result = cacheGetType(m.typeCache, sig)
-    if result == nil:
+    if result == "":
       result = getTypeName(m, origTyp, sig)
       if not (isImportedCppType(t) or
           (sfImportc in t.sym.flags and t.sym.magic == mNone)):
@@ -796,12 +790,12 @@ proc getTypeDescAux(m: BModule, origTyp: PType, check: var IntSet; kind: TSymKin
       # we cannot use getTypeForward here because then t would be associated
       # with the name of the struct, not with the pointer to the struct:
       result = cacheGetType(m.forwTypeCache, sig)
-      if result == nil:
+      if result == "":
         result = getTypeName(m, origTyp, sig)
         if not isImportedType(t):
           addForwardStructFormat(m, structOrUnion(t), result)
         m.forwTypeCache[sig] = result
-      assert(cacheGetType(m.typeCache, sig) == nil)
+      assert(cacheGetType(m.typeCache, sig) == "")
       m.typeCache[sig] = result & seqStar(m)
       if not isImportedType(t):
         if skipTypes(t[0], typedescInst).kind != tyEmpty:
@@ -837,25 +831,26 @@ proc getTypeDescAux(m: BModule, origTyp: PType, check: var IntSet; kind: TSymKin
            [foo, result, rope(n)])
   of tyObject, tyTuple:
     if isImportedCppType(t) and origTyp.kind == tyGenericInst:
-      let cppName = getTypeName(m, t, sig)
+      let cppNameAsRope = getTypeName(m, t, sig)
+      let cppName = $cppNameAsRope
       var i = 0
       var chunkStart = 0
 
       template addResultType(ty: untyped) =
         if ty == nil or ty.kind == tyVoid:
-          result.add(~"void")
+          result.add("void")
         elif ty.kind == tyStatic:
           internalAssert m.config, ty.n != nil
           result.add ty.n.renderTree
         else:
           result.add getTypeDescAux(m, ty, check, kind)
 
-      while i < cppName.data.len:
-        if cppName.data[i] == '\'':
+      while i < cppName.len:
+        if cppName[i] == '\'':
           var chunkEnd = i-1
           var idx, stars: int
-          if scanCppGenericSlot(cppName.data, i, idx, stars):
-            result.add cppName.data.substr(chunkStart, chunkEnd)
+          if scanCppGenericSlot(cppName, i, idx, stars):
+            result.add cppName.substr(chunkStart, chunkEnd)
             chunkStart = i
 
             let typeInSlot = resolveStarsInCppType(origTyp, idx + 1, stars)
@@ -864,9 +859,9 @@ proc getTypeDescAux(m: BModule, origTyp: PType, check: var IntSet; kind: TSymKin
           inc i
 
       if chunkStart != 0:
-        result.add cppName.data.substr(chunkStart)
+        result.add cppName.substr(chunkStart)
       else:
-        result = cppName & "<"
+        result = cppNameAsRope & "<"
         for i in 1..<origTyp.len-1:
           if i > 1: result.add(" COMMA ")
           addResultType(origTyp[i])
@@ -877,13 +872,13 @@ proc getTypeDescAux(m: BModule, origTyp: PType, check: var IntSet; kind: TSymKin
       # The resulting type will include commas and these won't play well
       # with the C macros for defining procs such as N_NIMCALL. We must
       # create a typedef for the type and use it in the proc signature:
-      let typedefName = ~"TY" & $sig
+      let typedefName = "TY" & $sig
       m.s[cfsTypes].addf("typedef $1 $2;$n", [result, typedefName])
       m.typeCache[sig] = typedefName
       result = typedefName
     else:
       result = cacheGetType(m.forwTypeCache, sig)
-      if result == nil:
+      if result == "":
         result = getTypeName(m, origTyp, sig)
         m.forwTypeCache[sig] = result
         if not isImportedType(t):
@@ -899,7 +894,9 @@ proc getTypeDescAux(m: BModule, origTyp: PType, check: var IntSet; kind: TSymKin
           discard # addAbiCheck(m, t, result) # already handled elsewhere
   of tySet:
     # Don't use the imported name as it may be scoped: 'Foo::SomeKind'
-    result = $t.kind & '_' & t.lastSon.typeName & $t.lastSon.hashType
+    result = rope("tySet_")
+    t.lastSon.typeName(result)
+    result.add $t.lastSon.hashType
     m.typeCache[sig] = result
     if not isImportedType(t):
       let s = int(getSize(m.config, t))
@@ -912,7 +909,7 @@ proc getTypeDescAux(m: BModule, origTyp: PType, check: var IntSet; kind: TSymKin
     result = getTypeDescAux(m, lastSon(t), check, kind)
   else:
     internalError(m.config, "getTypeDescAux(" & $t.kind & ')')
-    result = nil
+    result = ""
   # fixes bug #145:
   excl(check, t.id)
 
@@ -963,21 +960,12 @@ proc isReloadable(m: BModule, prc: PSym): bool =
 proc isNonReloadable(m: BModule, prc: PSym): bool =
   return m.hcrOn and sfNonReloadable in prc.flags
 
-proc genProcHeader(m: BModule, prc: PSym, asPtr: bool = false): Rope =
-  var
-    rettype, params: Rope
+proc genProcHeader(m: BModule, prc: PSym; result: var Rope; asPtr: bool = false) =
   # using static is needed for inline procs
-  if lfExportLib in prc.loc.flags:
-    if isHeaderFile in m.flags:
-      result.add "N_LIB_IMPORT "
-    else:
-      result.add "N_LIB_EXPORT "
-  elif prc.typ.callConv == ccInline or asPtr or isNonReloadable(m, prc):
-    result.add "static "
-  elif sfImportc notin prc.flags:
-    result.add "N_LIB_PRIVATE "
   var check = initIntSet()
-  fillLoc(prc.loc, locProc, prc.ast[namePos], mangleName(m, prc), OnUnknown)
+  fillBackendName(m, prc)
+  fillLoc(prc.loc, locProc, prc.ast[namePos], OnUnknown)
+  var rettype, params: Rope
   genProcParams(m, prc.typ, rettype, params, check)
   # handle the 2 options for hotcodereloading codegen - function pointer
   # (instead of forward declaration) or header for function body with "_actual" postfix
@@ -988,12 +976,21 @@ proc genProcHeader(m: BModule, prc: PSym, asPtr: bool = false): Rope =
   # careful here! don't access ``prc.ast`` as that could reload large parts of
   # the object graph!
   if prc.constraint.isNil:
+    if lfExportLib in prc.loc.flags:
+      if isHeaderFile in m.flags:
+        result.add "N_LIB_IMPORT "
+      else:
+        result.add "N_LIB_EXPORT "
+    elif prc.typ.callConv == ccInline or asPtr or isNonReloadable(m, prc):
+      result.add "static "
+    elif sfImportc notin prc.flags:
+      result.add "N_LIB_PRIVATE "
     result.addf("$1$2($3, $4)$5",
          [rope(CallingConvToStr[prc.typ.callConv]), asPtrStr, rettype, name,
          params])
   else:
     let asPtrStr = if asPtr: (rope("(*") & name & ")") else: name
-    result = runtimeFormat(prc.cgDeclFrmt, [rettype, asPtrStr, params])
+    result.add runtimeFormat(prc.cgDeclFrmt, [rettype, asPtrStr, params])
 
 # ------------------ type info generation -------------------------------------
 
@@ -1032,7 +1029,7 @@ proc genTypeInfoAuxBase(m: BModule; typ, origType: PType;
   #else echo("can contain a cycle: " & typeToString(typ))
   if flags != 0:
     m.s[cfsTypeInit3].addf("$1.flags = $2;$n", [nameHcr, rope(flags)])
-  discard cgsym(m, "TNimType")
+  cgsym(m, "TNimType")
   if isDefined(m.config, "nimTypeNames"):
     var typename = typeToString(if origType.typeInst != nil: origType.typeInst
                                 else: origType, preferName)
@@ -1040,16 +1037,16 @@ proc genTypeInfoAuxBase(m: BModule; typ, origType: PType;
       typename = "anon ref object from " & m.config$origType.skipTypes(skipPtrs).sym.info
     m.s[cfsTypeInit3].addf("$1.name = $2;$n",
         [nameHcr, makeCString typename])
-    discard cgsym(m, "nimTypeRoot")
+    cgsym(m, "nimTypeRoot")
     m.s[cfsTypeInit3].addf("$1.nextType = nimTypeRoot; nimTypeRoot=&$1;$n",
          [nameHcr])
 
   if m.hcrOn:
-    m.s[cfsData].addf("static TNimType* $1;$n", [name])
+    m.s[cfsStrData].addf("static TNimType* $1;$n", [name])
     m.hcrCreateTypeInfosProc.addf("\thcrRegisterGlobal($2, \"$1\", sizeof(TNimType), NULL, (void**)&$1);$n",
          [name, getModuleDllPath(m, m.module)])
   else:
-    m.s[cfsData].addf("N_LIB_PRIVATE TNimType $1;$n", [name])
+    m.s[cfsStrData].addf("N_LIB_PRIVATE TNimType $1;$n", [name])
 
 proc genTypeInfoAux(m: BModule, typ, origType: PType, name: Rope;
                     info: TLineInfo) =
@@ -1077,7 +1074,7 @@ proc discriminatorTableName(m: BModule, objtype: PType, d: PSym): Rope =
 proc rope(arg: Int128): Rope = rope($arg)
 
 proc discriminatorTableDecl(m: BModule, objtype: PType, d: PSym): Rope =
-  discard cgsym(m, "TNimNode")
+  cgsym(m, "TNimNode")
   var tmp = discriminatorTableName(m, objtype, d)
   result = "TNimNode* $1[$2];$n" % [tmp, rope(lengthOrd(m.config, d.typ)+1)]
 
@@ -1112,7 +1109,7 @@ proc genObjectFields(m: BModule, typ, origType: PType, n: PNode, expr: Rope;
     var tmp = discriminatorTableName(m, typ, field)
     var L = lengthOrd(m.config, field.typ)
     assert L > 0
-    if field.loc.r == nil: fillObjectFields(m, typ)
+    if field.loc.r == "": fillObjectFields(m, typ)
     if field.loc.t == nil:
       internalError(m.config, n.info, "genObjectFields")
     m.s[cfsTypeInit3].addf("$1.kind = 3;$n" &
@@ -1150,7 +1147,7 @@ proc genObjectFields(m: BModule, typ, origType: PType, n: PNode, expr: Rope;
     # Do not produce code for void types
     if isEmptyType(field.typ): return
     if field.bitsize == 0:
-      if field.loc.r == nil: fillObjectFields(m, typ)
+      if field.loc.r == "": fillObjectFields(m, typ)
       if field.loc.t == nil:
         internalError(m.config, n.info, "genObjectFields")
       m.s[cfsTypeInit3].addf("$1.kind = 1;$n" &
@@ -1244,7 +1241,7 @@ proc genSetInfo(m: BModule, typ: PType, name: Rope; info: TLineInfo) =
   assert(typ[0] != nil)
   genTypeInfoAux(m, typ, typ, name, info)
   var tmp = getNimNode(m)
-  m.s[cfsTypeInit3].addf("$1.len = $2; $1.kind = 0;$n" & "$3.node = &$1;$n",
+  m.s[cfsTypeInit3].addf("$1.len = $2; $1.kind = 0;$n$3.node = &$1;$n",
        [tmp, rope(firstOrd(m.config, typ)), tiNameForHcr(m, name)])
 
 proc genArrayInfo(m: BModule, typ: PType, name: Rope; info: TLineInfo) =
@@ -1269,11 +1266,11 @@ proc genDeepCopyProc(m: BModule; s: PSym; result: Rope) =
 proc declareNimType(m: BModule, name: string; str: Rope, module: int) =
   let nr = rope(name)
   if m.hcrOn:
-    m.s[cfsData].addf("static $2* $1;$n", [str, nr])
+    m.s[cfsStrData].addf("static $2* $1;$n", [str, nr])
     m.s[cfsTypeInit1].addf("\t$1 = ($3*)hcrGetGlobal($2, \"$1\");$n",
           [str, getModuleDllPath(m, module), nr])
   else:
-    m.s[cfsData].addf("extern $2 $1;$n", [str, nr])
+    m.s[cfsStrData].addf("extern $2 $1;$n", [str, nr])
 
 proc genTypeInfo2Name(m: BModule; t: PType): Rope =
   var res = "|"
@@ -1300,7 +1297,7 @@ proc genTypeInfo2Name(m: BModule; t: PType): Rope =
 
 proc isTrivialProc(g: ModuleGraph; s: PSym): bool {.inline.} = getBody(g, s).len == 0
 
-proc genHook(m: BModule; t: PType; info: TLineInfo; op: TTypeAttachedOp): Rope =
+proc genHook(m: BModule; t: PType; info: TLineInfo; op: TTypeAttachedOp; result: var Rope) =
   let theProc = getAttachedOp(m.g.graph, t, op)
   if theProc != nil and not isTrivialProc(m.g.graph, theProc):
     # the prototype of a destructor is ``=destroy(x: var T)`` and that of a
@@ -1311,7 +1308,7 @@ proc genHook(m: BModule; t: PType; info: TLineInfo; op: TTypeAttachedOp): Rope =
         theProc.name.s & " needs to have the 'nimcall' calling convention")
 
     genProc(m, theProc)
-    result = theProc.loc.r
+    result.add theProc.loc.r
 
     when false:
       if not canFormAcycle(t) and op == attachedTrace:
@@ -1323,7 +1320,7 @@ proc genHook(m: BModule; t: PType; info: TLineInfo; op: TTypeAttachedOp): Rope =
         # unfortunately this check is wrong for an object type that only contains
         # .cursor fields like 'Node' inside 'cycleleak'.
         internalError(m.config, info, "no attached trace proc found")
-    result = rope("NIM_NIL")
+    result.add rope("NIM_NIL")
 
 proc genTypeInfoV2Impl(m: BModule, t, origType: PType, name: Rope; info: TLineInfo) =
   var typeName: Rope
@@ -1335,17 +1332,23 @@ proc genTypeInfoV2Impl(m: BModule, t, origType: PType, name: Rope; info: TLineIn
   else:
     typeName = rope("NIM_NIL")
 
-  discard cgsym(m, "TNimTypeV2")
-  m.s[cfsData].addf("N_LIB_PRIVATE TNimTypeV2 $1;$n", [name])
-  let destroyImpl = genHook(m, t, info, attachedDestructor)
-  let traceImpl = genHook(m, t, info, attachedTrace)
+  cgsym(m, "TNimTypeV2")
+  m.s[cfsStrData].addf("N_LIB_PRIVATE TNimTypeV2 $1;$n", [name])
 
   var flags = 0
   if not canFormAcycle(t): flags = flags or 1
 
-  addf(m.s[cfsTypeInit3], "$1.destructor = (void*)$2; $1.size = sizeof($3); $1.align = NIM_ALIGNOF($3); $1.name = $4;$n; $1.traceImpl = (void*)$5; $1.flags = $6;", [
-    name, destroyImpl, getTypeDesc(m, t), typeName,
-    traceImpl, rope(flags)])
+  var typeEntry = newRopeAppender()
+  addf(typeEntry, "$1.destructor = (void*)", [name])
+  genHook(m, t, info, attachedDestructor, typeEntry)
+
+  addf(typeEntry, "; $1.traceImpl = (void*)", [name])
+  genHook(m, t, info, attachedTrace, typeEntry)
+
+  addf(typeEntry, "; $1.name = $2;$n; $1.size = sizeof($3); $1.align = NIM_ALIGNOF($3); $1.flags = $4;",
+    [name, typeName, getTypeDesc(m, t), rope(flags)])
+
+  m.s[cfsTypeInit3].add typeEntry
 
   if t.kind == tyObject and t.len > 0 and t[0] != nil and optEnableDeepCopy in m.config.globalOptions:
     discard genTypeInfoV1(m, t, info)
@@ -1359,12 +1362,12 @@ proc genTypeInfoV2(m: BModule, t: PType; info: TLineInfo): Rope =
 
   let sig = hashType(origType)
   result = m.typeInfoMarkerV2.getOrDefault(sig)
-  if result != nil:
+  if result != "":
     return prefixTI.rope & result & ")".rope
 
   let marker = m.g.typeInfoMarkerV2.getOrDefault(sig)
-  if marker.str != nil:
-    discard cgsym(m, "TNimTypeV2")
+  if marker.str != "":
+    cgsym(m, "TNimTypeV2")
     declareNimType(m, "TNimTypeV2", marker.str, marker.owner)
     # also store in local type section:
     m.typeInfoMarkerV2[sig] = marker.str
@@ -1378,7 +1381,7 @@ proc genTypeInfoV2(m: BModule, t: PType; info: TLineInfo): Rope =
     # make sure the type info is created in the owner module
     discard genTypeInfoV2(m.g.modules[owner], origType, info)
     # reference the type info as extern here
-    discard cgsym(m, "TNimTypeV2")
+    cgsym(m, "TNimTypeV2")
     declareNimType(m, "TNimTypeV2", result, owner)
     return prefixTI.rope & result & ")".rope
 
@@ -1430,13 +1433,13 @@ proc genTypeInfoV1(m: BModule, t: PType; info: TLineInfo): Rope =
 
   let sig = hashType(origType)
   result = m.typeInfoMarker.getOrDefault(sig)
-  if result != nil:
+  if result != "":
     return prefixTI.rope & result & ")".rope
 
   let marker = m.g.typeInfoMarker.getOrDefault(sig)
-  if marker.str != nil:
-    discard cgsym(m, "TNimType")
-    discard cgsym(m, "TNimNode")
+  if marker.str != "":
+    cgsym(m, "TNimType")
+    cgsym(m, "TNimNode")
     declareNimType(m, "TNimType", marker.str, marker.owner)
     # also store in local type section:
     m.typeInfoMarker[sig] = marker.str
@@ -1447,8 +1450,8 @@ proc genTypeInfoV1(m: BModule, t: PType; info: TLineInfo): Rope =
 
   let old = m.g.graph.emittedTypeInfo.getOrDefault($result)
   if old != FileIndex(0):
-    discard cgsym(m, "TNimType")
-    discard cgsym(m, "TNimNode")
+    cgsym(m, "TNimType")
+    cgsym(m, "TNimNode")
     declareNimType(m, "TNimType", result, old.int)
     return prefixTI.rope & result & ")".rope
 
@@ -1457,8 +1460,8 @@ proc genTypeInfoV1(m: BModule, t: PType; info: TLineInfo): Rope =
     # make sure the type info is created in the owner module
     discard genTypeInfoV1(m.g.modules[owner], origType, info)
     # reference the type info as extern here
-    discard cgsym(m, "TNimType")
-    discard cgsym(m, "TNimNode")
+    cgsym(m, "TNimType")
+    cgsym(m, "TNimNode")
     declareNimType(m, "TNimType", result, owner)
     return prefixTI.rope & result & ")".rope
   else:
diff --git a/compiler/cgen.nim b/compiler/cgen.nim
index 1e26081089f02..794abc1ad6a5b 100644
--- a/compiler/cgen.nim
+++ b/compiler/cgen.nim
@@ -23,7 +23,7 @@ when defined(nimPreviewSlimSystem):
 when not defined(leanCompiler):
   import spawn, semparallel
 
-import strutils except `%` # collides with ropes.`%`
+import strutils except `%`, addf # collides with ropes.`%`
 
 from ic / ic import ModuleBackendFlag
 import dynlib
@@ -63,16 +63,23 @@ proc initLoc(result: var TLoc, k: TLocKind, lode: PNode, s: TStorageLoc) =
   result.k = k
   result.storage = s
   result.lode = lode
-  result.r = nil
+  result.r = ""
   result.flags = {}
 
-proc fillLoc(a: var TLoc, k: TLocKind, lode: PNode, r: Rope, s: TStorageLoc) =
+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.r == "": a.r = 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
-    if a.r == nil: a.r = r
 
 proc t(a: TLoc): PType {.inline.} =
   if a.lode.kind == nkSym:
@@ -96,7 +103,8 @@ proc useHeader(m: BModule, sym: PSym) =
     let str = getStr(sym.annex.path)
     m.includeHeader(str)
 
-proc cgsym(m: BModule, name: string): Rope
+proc cgsym(m: BModule, name: string)
+proc cgsymValue(m: BModule, name: string): Rope
 
 proc getCFile(m: BModule): AbsoluteFile
 
@@ -113,10 +121,6 @@ proc getModuleDllPath(m: BModule, s: PSym): Rope =
 
 import macros
 
-proc cgFormatValue(result: var string; value: Rope) =
-  for str in leaves(value):
-    result.add str
-
 proc cgFormatValue(result: var string; value: string) =
   result.add value
 
@@ -197,7 +201,7 @@ macro ropecg(m: BModule, frmt: static[FormatStr], args: untyped): Rope =
       var ident = newLit(substr(frmt, i, j-1))
       i = j
       flushStrLit()
-      result.add newCall(formatValue, resVar, newCall(ident"cgsym", m, ident))
+      result.add newCall(formatValue, resVar, newCall(ident"cgsymValue", m, ident))
     elif frmt[i] == '#' and frmt[i+1] == '$':
       inc(i, 2)
       var j = 0
@@ -206,7 +210,7 @@ macro ropecg(m: BModule, frmt: static[FormatStr], args: untyped): Rope =
         inc(i)
       let ident = args[j-1]
       flushStrLit()
-      result.add newCall(formatValue, resVar, newCall(ident"cgsym", m, ident))
+      result.add newCall(formatValue, resVar, newCall(ident"cgsymValue", m, ident))
     var start = i
     while i < frmt.len:
       if frmt[i] != '$' and frmt[i] != '#': inc(i)
@@ -217,10 +221,9 @@ macro ropecg(m: BModule, frmt: static[FormatStr], args: untyped): Rope =
   flushStrLit()
   result.add newCall(ident"rope", resVar)
 
-proc indentLine(p: BProc, r: Rope): Rope =
-  result = r
+proc addIndent(p: BProc; result: var Rope) =
   for i in 0..<p.blocks.len:
-    prepend(result, "\t".rope)
+    result.add "\t".rope
 
 template appcg(m: BModule, c: var Rope, frmt: FormatStr,
            args: untyped) =
@@ -234,23 +237,24 @@ 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: Rope) =
-  p.s(sec).add(indentLine(p, r))
-
 template line(p: BProc, sec: TCProcSection, r: string) =
-  p.s(sec).add(indentLine(p, r.rope))
+  addIndent p, p.s(sec)
+  p.s(sec).add(r)
 
 template lineF(p: BProc, sec: TCProcSection, frmt: FormatStr,
               args: untyped) =
-  p.s(sec).add(indentLine(p, frmt % args))
+  addIndent p, p.s(sec)
+  p.s(sec).add(frmt % args)
 
 template lineCg(p: BProc, sec: TCProcSection, frmt: FormatStr,
                args: untyped) =
-  p.s(sec).add(indentLine(p, ropecg(p.module, frmt, args)))
+  addIndent p, p.s(sec)
+  p.s(sec).add(ropecg(p.module, frmt, args))
 
 template linefmt(p: BProc, sec: TCProcSection, frmt: FormatStr,
              args: untyped) =
-  p.s(sec).add(indentLine(p, ropecg(p.module, frmt, args)))
+  addIndent p, p.s(sec)
+  p.s(sec).add(ropecg(p.module, frmt, args))
 
 proc safeLineNm(info: TLineInfo): int =
   result = toLinenumber(info)
@@ -276,7 +280,7 @@ proc genLineDir(p: BProc, t: PNode) =
   let line = t.info.safeLineNm
 
   if optEmbedOrigSrc in p.config.globalOptions:
-    p.s(cpsStmts).add(~"//" & sourceLine(p.config, t.info) & "\L")
+    p.s(cpsStmts).add("//" & sourceLine(p.config, t.info) & "\L")
   genCLineDir(p.s(cpsStmts), toFullPath(p.config, t.info), line, p.config)
   if ({optLineTrace, optStackTrace} * p.options == {optLineTrace, optStackTrace}) and
       (p.prc == nil or sfPure notin p.prc.flags) and t.info.fileIndex != InvalidFileIdx:
@@ -287,7 +291,7 @@ proc genLineDir(p: BProc, t: PNode) =
 proc accessThreadLocalVar(p: BProc, s: PSym)
 proc emulatedThreadVars(conf: ConfigRef): bool {.inline.}
 proc genProc(m: BModule, prc: PSym)
-proc raiseInstr(p: BProc): Rope
+proc raiseInstr(p: BProc; result: var Rope)
 
 template compileToCpp(m: BModule): untyped =
   m.config.backend == backendCpp or sfCompileToCpp in m.module.flags
@@ -298,10 +302,18 @@ proc getTempName(m: BModule): Rope =
 
 proc rdLoc(a: TLoc): Rope =
   # 'read' location (deref if indirect)
-  result = a.r
-  if lfIndirect in a.flags: result = "(*$1)" % [result]
+  if lfIndirect in a.flags:
+    result = "(*" & a.r & ")"
+  else:
+    result = a.r
+
+proc addRdLoc(a: TLoc; result: var Rope) =
+  if lfIndirect in a.flags:
+    result.add "(*" & a.r & ")"
+  else:
+    result.add a.r
 
-proc lenField(p: BProc): Rope =
+proc lenField(p: BProc): Rope {.inline.} =
   result = rope(if p.module.compileToCpp: "len" else: "Sup.len")
 
 proc lenExpr(p: BProc; a: TLoc): Rope =
@@ -326,16 +338,24 @@ template mapTypeChooser(n: PNode): TSymKind =
 
 template mapTypeChooser(a: TLoc): TSymKind = mapTypeChooser(a.lode)
 
+proc addAddrLoc(conf: ConfigRef; a: TLoc; result: var Rope) =
+  if lfIndirect notin a.flags and mapType(conf, a.t, mapTypeChooser(a)) != ctArray:
+    result.add "(&" & a.r & ")"
+  else:
+    result.add a.r
+
 proc addrLoc(conf: ConfigRef; a: TLoc): Rope =
-  result = a.r
   if lfIndirect notin a.flags and mapType(conf, a.t, mapTypeChooser(a)) != ctArray:
-    result = "(&" & result & ")"
+    result = "(&" & a.r & ")"
+  else:
+    result = a.r
 
 proc byRefLoc(p: BProc; a: TLoc): Rope =
-  result = a.r
   if lfIndirect notin a.flags and mapType(p.config, a.t, mapTypeChooser(a)) != ctArray and not
       p.module.compileToCpp:
-    result = "(&" & result & ")"
+    result = "(&" & a.r & ")"
+  else:
+    result = a.r
 
 proc rdCharLoc(a: TLoc): Rope =
   # read a location that may need a char-cast:
@@ -416,7 +436,7 @@ proc resetLoc(p: BProc, loc: var TLoc) =
   let typ = skipTypes(loc.t, abstractVarRange)
   if isImportedCppType(typ): return
   if optSeqDestructors in p.config.globalOptions and typ.kind in {tyString, tySequence}:
-    assert rdLoc(loc) != nil
+    assert loc.r != ""
 
     let atyp = skipTypes(loc.t, abstractInst)
     if atyp.kind in {tyVar, tyLent}:
@@ -523,7 +543,8 @@ proc getIntTemp(p: BProc, result: var TLoc) =
 proc localVarDecl(p: BProc; n: PNode): Rope =
   let s = n.sym
   if s.loc.k == locNone:
-    fillLoc(s.loc, locLocalVar, n, mangleLocalName(p, s), OnStack)
+    fillLocalName(p, s)
+    fillLoc(s.loc, locLocalVar, n, OnStack)
     if s.kind == skLet: incl(s.loc.flags, lfNoDeepCopy)
   if s.kind in {skLet, skVar, skField, skForVar} and s.alignment > 0:
     result.addf("NIM_ALIGN($1) ", [rope(s.alignment)])
@@ -560,7 +581,8 @@ proc treatGlobalDifferentlyForHCR(m: BModule, s: PSym): bool =
 proc assignGlobalVar(p: BProc, n: PNode; value: Rope) =
   let s = n.sym
   if s.loc.k == locNone:
-    fillLoc(s.loc, locGlobalVar, n, mangleName(p.module, s), OnHeap)
+    fillBackendName(p.module, s)
+    fillLoc(s.loc, locGlobalVar, n, OnHeap)
     if treatGlobalDifferentlyForHCR(p.module, s): incl(s.loc.flags, lfIndirect)
 
   if lfDynamicLib in s.loc.flags:
@@ -569,7 +591,7 @@ proc assignGlobalVar(p: BProc, n: PNode; value: Rope) =
       varInDynamicLib(q, s)
     else:
       s.loc.r = mangleDynLibProc(s)
-    if value != nil:
+    if value != "":
       internalError(p.config, n.info, ".dynlib variables cannot have a value")
     return
   useHeader(p.module, s)
@@ -577,10 +599,10 @@ proc assignGlobalVar(p: BProc, n: PNode; value: Rope) =
   if not containsOrIncl(p.module.declaredThings, s.id):
     if sfThread in s.flags:
       declareThreadVar(p.module, s, sfImportc in s.flags)
-      if value != nil:
+      if value != "":
         internalError(p.config, n.info, ".threadvar variables cannot have a value")
     else:
-      var decl: Rope = nil
+      var decl: Rope = ""
       var td = getTypeDesc(p.module, s.loc.t, skVar)
       if s.constraint.isNil:
         if s.kind in {skLet, skVar, skField, skForVar} and s.alignment > 0:
@@ -589,34 +611,35 @@ proc assignGlobalVar(p: BProc, n: PNode; value: Rope) =
         elif sfImportc in s.flags: decl.add("extern ")
         elif lfExportLib in s.loc.flags: decl.add("N_LIB_EXPORT_VAR ")
         else: decl.add("N_LIB_PRIVATE ")
-        if s.kind == skLet and value != nil: decl.add("NIM_CONST ")
+        if s.kind == skLet and value != "": decl.add("NIM_CONST ")
         decl.add(td)
         if p.hcrOn: decl.add("*")
         if sfRegister in s.flags: decl.add(" register")
         if sfVolatile in s.flags: decl.add(" volatile")
         if sfNoalias in s.flags: decl.add(" NIM_NOALIAS")
-        if value != nil:
+        if value != "":
           decl.addf(" $1 = $2;$n", [s.loc.r, value])
         else:
           decl.addf(" $1;$n", [s.loc.r])
       else:
-        if value != nil:
+        if value != "":
           decl = runtimeFormat(s.cgDeclFrmt & " = $#;$n", [td, s.loc.r, value])
         else:
           decl = runtimeFormat(s.cgDeclFrmt & ";$n", [td, s.loc.r])
       p.module.s[cfsVars].add(decl)
-  if p.withinLoop > 0 and value == nil:
+  if p.withinLoop > 0 and value == "":
     # fixes tests/run/tzeroarray:
     resetLoc(p, s.loc)
 
 proc assignParam(p: BProc, s: PSym, retType: PType) =
-  assert(s.loc.r != nil)
+  assert(s.loc.r != "")
   scopeMangledParam(p, s)
 
 proc fillProcLoc(m: BModule; n: PNode) =
   let sym = n.sym
   if sym.loc.k == locNone:
-    fillLoc(sym.loc, locProc, n, mangleName(m, sym), OnStack)
+    fillBackendName(m, sym)
+    fillLoc(sym.loc, locProc, n, OnStack)
 
 proc getLabel(p: BProc): TLabel =
   inc(p.labels)
@@ -631,9 +654,9 @@ proc genStmts(p: BProc, t: PNode)
 proc expr(p: BProc, n: PNode, d: var TLoc)
 proc genProcPrototype(m: BModule, sym: PSym)
 proc putLocIntoDest(p: BProc, d: var TLoc, s: TLoc)
-proc intLiteral(i: BiggestInt): Rope
-proc genLiteral(p: BProc, n: PNode): Rope
-proc genOtherArg(p: BProc; ri: PNode; i: int; typ: PType): Rope
+proc intLiteral(i: BiggestInt; result: var Rope)
+proc genLiteral(p: BProc, n: PNode; result: var Rope)
+proc genOtherArg(p: BProc; ri: PNode; i: int; typ: PType; result: var Rope; argsCounter: var int)
 proc raiseExit(p: BProc)
 
 proc initLocExpr(p: BProc, e: PNode, result: var TLoc) =
@@ -671,11 +694,11 @@ proc initFrame(p: BProc, procname, filename: Rope): Rope =
   if p.module.s[cfsFrameDefines].len == 0:
     appcg(p.module, p.module.s[cfsFrameDefines], frameDefines, ["#"])
 
-  discard cgsym(p.module, "nimFrame")
+  cgsym(p.module, "nimFrame")
   result = ropecg(p.module, "\tnimfr_($1, $2);$n", [procname, filename])
 
 proc initFrameNoDebug(p: BProc; frame, procname, filename: Rope; line: int): Rope =
-  discard cgsym(p.module, "nimFrame")
+  cgsym(p.module, "nimFrame")
   p.blocks[0].sections[cpsLocals].addf("TFrame $1;$n", [frame])
   result = ropecg(p.module, "\t$1.procname = $2; $1.filename = $3; " &
                       " $1.line = $4; $1.len = -1; nimFrame(&$1);$n",
@@ -702,24 +725,28 @@ proc loadDynamicLib(m: BModule, lib: PLib) =
   if not lib.generated:
     lib.generated = true
     var tmp = getTempName(m)
-    assert(lib.name == nil)
+    assert(lib.name == "")
     lib.name = tmp # BUGFIX: cgsym has awful side-effects
     m.s[cfsVars].addf("static void* $1;$n", [tmp])
     if lib.path.kind in {nkStrLit..nkTripleStrLit}:
       var s: TStringSeq = @[]
       libCandidates(lib.path.strVal, s)
       rawMessage(m.config, hintDependency, lib.path.strVal)
-      var loadlib: Rope = nil
+      var loadlib: Rope = ""
       for i in 0..high(s):
         inc(m.labels)
         if i > 0: loadlib.add("||")
         let n = newStrNode(nkStrLit, s[i])
         n.info = lib.path.info
-        appcg(m, loadlib, "($1 = #nimLoadLibrary($2))$n",
-              [tmp, genStringLiteral(m, n)])
+        appcg(m, loadlib, "($1 = #nimLoadLibrary(", [tmp])
+        genStringLiteral(m, n, loadlib)
+        loadlib.addf "))$n", []
       appcg(m, m.s[cfsDynLibInit],
-            "if (!($1)) #nimLoadLibraryError($2);$n",
-            [loadlib, genStringLiteral(m, lib.path)])
+            "if (!($1)) #nimLoadLibraryError(",
+            [loadlib])
+      genStringLiteral(m, lib.path, m.s[cfsDynLibInit])
+      m.s[cfsDynLibInit].addf ");$n", []
+
     else:
       var p = newProc(nil, m)
       p.options.excl optStackTrace
@@ -738,7 +765,7 @@ proc loadDynamicLib(m: BModule, lib: PLib) =
            "if (!($1 = #nimLoadLibrary($2))) #nimLoadLibraryError($2);$n",
            [tmp, rdLoc(dest)])
 
-  if lib.name == nil: internalError(m.config, "loadDynamicLib")
+  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
@@ -803,18 +830,25 @@ proc symInDynamicLibPartial(m: BModule, sym: PSym) =
   sym.loc.r = mangleDynLibProc(sym)
   sym.typ.sym = nil           # generate a new name
 
-proc cgsym(m: BModule, name: string): Rope =
+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:
-    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: " & name & ": " & $sym.kind)
+    cgsymImpl m, sym
   else:
-    # we used to exclude the system module from this check, but for DLL
-    # generation support this sloppyness leads to hard to detect bugs, so
-    # we're picky here for the system module too:
     rawMessage(m.config, errGenerated, "system module needs: " & name)
   result = sym.loc.r
   if m.hcrOn and sym != nil and sym.kind in {skProc..skIterator}:
@@ -845,12 +879,12 @@ proc generateHeaders(m: BModule) =
 #undef unix
 """)
 
-proc openNamespaceNim(namespace: string): Rope =
+proc openNamespaceNim(namespace: string; result: var Rope) =
   result.add("namespace ")
   result.add(namespace)
   result.add(" {\L")
 
-proc closeNamespaceNim(): Rope =
+proc closeNamespaceNim(result: var Rope) =
   result.add("}\L")
 
 proc closureSetup(p: BProc, prc: PSym) =
@@ -1028,8 +1062,9 @@ proc isNoReturn(m: BModule; s: PSym): bool {.inline.} =
 
 proc genProcAux(m: BModule, prc: PSym) =
   var p = newProc(prc, m)
-  var header = genProcHeader(m, prc)
-  var returnStmt: Rope = nil
+  var header = newRopeAppender()
+  genProcHeader(m, prc, header)
+  var returnStmt: Rope = ""
   assert(prc.ast != nil)
 
   var procBody = transformBody(m.g.graph, m.idgen, prc, cache = false)
@@ -1051,7 +1086,7 @@ proc genProcAux(m: BModule, prc: PSym) =
       else:
         # declare the result symbol:
         assignLocalVar(p, resNode)
-        assert(res.loc.r != nil)
+        assert(res.loc.r != "")
         initLocalVar(p, res, immediateAsgn=false)
       returnStmt = ropecg(p.module, "\treturn $1;$n", [rdLoc(res.loc)])
     else:
@@ -1109,10 +1144,10 @@ proc genProcAux(m: BModule, prc: PSym) =
     if beforeRetNeeded in p.flags: generatedProc.add("{")
     generatedProc.add(p.s(cpsInit))
     generatedProc.add(p.s(cpsStmts))
-    if beforeRetNeeded in p.flags: generatedProc.add(~"\t}BeforeRet_: ;$n")
+    if beforeRetNeeded in p.flags: generatedProc.add("\t}BeforeRet_: ;\n")
     if optStackTrace in prc.options: generatedProc.add(deinitFrame(p))
     generatedProc.add(returnStmt)
-    generatedProc.add(~"}$N")
+    generatedProc.add("}\n")
   m.s[cfsProcs].add(generatedProc)
   if isReloadable(m, prc):
     m.s[cfsDynLibInit].addf("\t$1 = ($3) hcrRegisterProc($4, \"$1\", (void*)$2);$n",
@@ -1141,7 +1176,8 @@ proc genProcPrototype(m: BModule, sym: PSym) =
              [mangleDynLibProc(sym), getTypeDesc(m, sym.loc.t), getModuleDllPath(m, sym)])
   elif not containsOrIncl(m.declaredProtos, sym.id):
     let asPtr = isReloadable(m, sym)
-    var header = genProcHeader(m, sym, asPtr)
+    var header = newRopeAppender()
+    genProcHeader(m, sym, header, asPtr)
     if not asPtr:
       if isNoReturn(m, sym) and hasDeclspec in extccomp.CC[m.config.cCompiler].props:
         header = "__declspec(noreturn) " & header
@@ -1159,7 +1195,7 @@ proc genProcNoForward(m: BModule, prc: PSym) =
     fillProcLoc(m, prc.ast[namePos])
     useHeader(m, prc)
     # dependency to a compilerproc:
-    discard cgsym(m, prc.name.s)
+    cgsym(m, prc.name.s)
     return
   if lfNoDecl in prc.loc.flags:
     fillProcLoc(m, prc.ast[namePos])
@@ -1250,14 +1286,15 @@ proc genVarPrototype(m: BModule, n: PNode) =
   #assert(sfGlobal in sym.flags)
   let sym = n.sym
   useHeader(m, sym)
-  fillLoc(sym.loc, locGlobalVar, n, mangleName(m, sym), OnHeap)
+  fillBackendName(m, sym)
+  fillLoc(sym.loc, locGlobalVar, n, OnHeap)
   if treatGlobalDifferentlyForHCR(m, sym): incl(sym.loc.flags, lfIndirect)
 
   if (lfNoDecl in sym.loc.flags) or contains(m.declaredThings, sym.id):
     return
   if sym.owner.id != m.module.id:
     # else we already have the symbol generated!
-    assert(sym.loc.r != nil)
+    assert(sym.loc.r != "")
     if sfThread in sym.flags:
       declareThreadVar(m, sym, true)
     else:
@@ -1343,9 +1380,11 @@ proc genMainProc(m: BModule) =
       assert prc != nil
       let n = newStrNode(nkStrLit, prc.annex.path.strVal)
       n.info = prc.annex.path.info
+      var strLit = newRopeAppender()
+      genStringLiteral(m, n, strLit)
       appcg(m, result, "\tif (!($1 = #nimLoadLibrary($2)))$N" &
                        "\t\t#nimLoadLibraryError($2);$N",
-                       [handle, genStringLiteral(m, n)])
+                       [handle, strLit])
 
     preMainCode.add(loadLib("hcr_handle", "hcrGetProc"))
     preMainCode.add("\tvoid* rtl_handle;\L")
@@ -1526,7 +1565,8 @@ proc genMainProc(m: BModule) =
 
   if optNoMain notin m.config.globalOptions:
     if m.config.cppCustomNamespace.len > 0:
-      m.s[cfsProcs].add closeNamespaceNim() & "using namespace " & m.config.cppCustomNamespace & ";\L"
+      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} != {}:
@@ -1550,7 +1590,7 @@ proc genMainProc(m: BModule) =
       appcg(m, m.s[cfsProcs], otherMain, [if m.hcrOn: "*" else: "", m.config.nimMainPrefix])
 
     if m.config.cppCustomNamespace.len > 0:
-      m.s[cfsProcs].add openNamespaceNim(m.config.cppCustomNamespace)
+      openNamespaceNim(m.config.cppCustomNamespace, m.s[cfsProcs])
 
 proc registerInitProcs*(g: BModuleList; m: PSym; flags: set[ModuleBackendFlag]) =
   ## Called from the IC backend.
@@ -1733,7 +1773,7 @@ proc genInitCode(m: BModule) =
     # Give this small function its own scope
     prc.addf("{$N", [])
     # Keep a bogus frame in case the code needs one
-    prc.add(~"\tTFrame FR_; FR_.len = 0;$N")
+    prc.add("\tTFrame FR_; FR_.len = 0;\n")
 
     writeSection(preInitProc, cpsLocals)
     writeSection(preInitProc, cpsInit, m.hcrOn)
@@ -1759,13 +1799,13 @@ proc genInitCode(m: BModule) =
         var procname = makeCString(m.module.name.s)
         prc.add(initFrame(m.initProc, procname, quotedFilename(m.config, m.module.info)))
       else:
-        prc.add(~"\tTFrame FR_; FR_.len = 0;$N")
+        prc.add("\tTFrame FR_; FR_.len = 0;\n")
 
     writeSection(initProc, cpsInit, m.hcrOn)
     writeSection(initProc, cpsStmts)
 
     if beforeRetNeeded in m.initProc.flags:
-      prc.add(~"\tBeforeRet_: ;$n")
+      prc.add("\tBeforeRet_: ;\n")
 
     if sfMainModule in m.module.flags and m.config.exc == excGoto:
       if getCompilerProc(m.g.graph, "nimTestErrorFlag") != nil:
@@ -1796,7 +1836,7 @@ proc genInitCode(m: BModule) =
     m.s[cfsInitProc].addf("}$N$N", [])
 
   for i, el in pairs(m.extensionLoaders):
-    if el != nil:
+    if el != "":
       let ex = "NIM_EXTERNC N_NIMCALL(void, nimLoadProcs$1)(void) {$2}$N$N" %
         [(i.ord - '0'.ord).rope, el]
       moduleInitRequired = true
@@ -1824,7 +1864,7 @@ proc genModule(m: BModule, cfile: Cfile): Rope =
   generateHeaders(m)
   result.add(m.s[cfsHeaders])
   if m.config.cppCustomNamespace.len > 0:
-    result.add openNamespaceNim(m.config.cppCustomNamespace)
+    openNamespaceNim(m.config.cppCustomNamespace, result)
   if m.s[cfsFrameDefines].len > 0:
     result.add(m.s[cfsFrameDefines])
   else:
@@ -1843,10 +1883,10 @@ proc genModule(m: BModule, cfile: Cfile): Rope =
     result.add(m.s[cfsDatInitProc])
 
   if m.config.cppCustomNamespace.len > 0:
-    result.add closeNamespaceNim()
+    closeNamespaceNim(result)
 
   if moduleIsEmpty:
-    result = nil
+    result = ""
 
 proc initProcOptions(m: BModule): TOptions =
   let opts = m.config.options
@@ -1867,6 +1907,7 @@ proc rawNewModule(g: BModuleList; module: PSym, filename: AbsoluteFile): BModule
   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] = newRopeAppender()
   result.initProc.options = initProcOptions(result)
   result.preInitProc = newProc(nil, result)
   result.preInitProc.flags.incl nimErrorFlagDisabled
@@ -1924,13 +1965,14 @@ proc writeHeader(m: BModule) =
   generateThreadLocalStorage(m)
   for i in cfsHeaders..cfsProcs:
     result.add(m.s[i])
-    if m.config.cppCustomNamespace.len > 0 and i == cfsHeaders: result.add openNamespaceNim(m.config.cppCustomNamespace)
+    if m.config.cppCustomNamespace.len > 0 and i == cfsHeaders:
+      openNamespaceNim(m.config.cppCustomNamespace, result)
   result.add(m.s[cfsInitProc])
 
   if optGenDynLib in m.config.globalOptions:
     result.add("N_LIB_IMPORT ")
   result.addf("N_CDECL(void, $1NimMain)(void);$n", [rope m.config.nimMainPrefix])
-  if m.config.cppCustomNamespace.len > 0: result.add closeNamespaceNim()
+  if m.config.cppCustomNamespace.len > 0: closeNamespaceNim(result)
   result.addf("#endif /* $1 */$n", [guard])
   if not writeRope(result, m.filename):
     rawMessage(m.config, errCannotOpenFile, m.filename.string)
@@ -2034,7 +2076,7 @@ proc writeModule(m: BModule, pending: bool) =
   var cf = Cfile(nimname: m.module.name.s, cname: cfile,
                   obj: completeCfilePath(m.config, toObjFile(m.config, cfile)), flags: {})
   var code = genModule(m, cf)
-  if code != nil or m.config.symbolFiles != disabledSf:
+  if code != "" or m.config.symbolFiles != disabledSf:
     when hasTinyCBackend:
       if m.config.cmd == cmdTcc:
         tccgen.compileCCode($code, m.config)
@@ -2060,7 +2102,7 @@ proc finalCodegenActions*(graph: ModuleGraph; m: BModule; n: PNode) =
     # 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:
-      discard cgsym(m, "nimTestErrorFlag")
+      cgsym(m, "nimTestErrorFlag")
 
     if {optGenStaticLib, optGenDynLib, optNoMain} * m.config.globalOptions == {}:
       for i in countdown(high(graph.globalDestructors), 0):
@@ -2076,7 +2118,7 @@ proc finalCodegenActions*(graph: ModuleGraph; m: BModule; n: PNode) =
 
     if m.hcrOn:
       # make sure this is pulled in (meaning hcrGetGlobal() is called for it during init)
-      discard cgsym(m, "programResult")
+      cgsym(m, "programResult")
       if m.inHcrInitGuard:
         endBlock(m.initProc)
 
@@ -2086,17 +2128,17 @@ proc finalCodegenActions*(graph: ModuleGraph; m: BModule; n: PNode) =
         # 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
-        discard cgsym(m, "nimLoadLibrary")
-        discard cgsym(m, "nimLoadLibraryError")
-        discard cgsym(m, "nimGetProcAddr")
-        discard cgsym(m, "procAddrError")
-        discard cgsym(m, "rawWrite")
+        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, gcOrc}:
-        discard cgsym(m, "initStackBottomWith")
+        cgsym(m, "initStackBottomWith")
       if emulatedThreadVars(m.config) and m.config.target.targetOS != osStandalone:
-        discard cgsym(m, "initThreadVarsEmulation")
+        cgsym(m, "initThreadVarsEmulation")
 
       if m.g.forwardedProcs.len == 0:
         incl m.flags, objHasKidsValid
diff --git a/compiler/cgendata.nim b/compiler/cgendata.nim
index 4490767254fe6..d017fdd1e48f3 100644
--- a/compiler/cgendata.nim
+++ b/compiler/cgendata.nim
@@ -27,6 +27,7 @@ type
     cfsFieldInfo,             # section for field information
     cfsTypeInfo,              # section for type information (ag ABI checks)
     cfsProcHeaders,           # section for C procs prototypes
+    cfsStrData,               # section for constant string literals
     cfsData,                  # section for C constant data
     cfsVars,                  # section for C variable declarations
     cfsProcs,                 # section for C procs that are not inline
@@ -190,13 +191,18 @@ proc procSec*(p: BProc, s: TCProcSection): var Rope {.inline.} =
   # top level proc sections
   result = p.blocks[0].sections[s]
 
+proc initBlock*(): TBlock =
+  result = TBlock()
+  for i in low(result.sections)..high(result.sections):
+    result.sections[i] = newRopeAppender()
+
 proc newProc*(prc: PSym, module: BModule): BProc =
   new(result)
   result.prc = prc
   result.module = module
   result.options = if prc != nil: prc.options
                    else: module.config.options
-  newSeq(result.blocks, 1)
+  result.blocks = @[initBlock()]
   result.nestedTryStmts = @[]
   result.finallySafePoints = @[]
   result.sigConflicts = initCountTable[string]()
diff --git a/compiler/cgmeth.nim b/compiler/cgmeth.nim
index dab8826c15ed9..6b4322a13f1bd 100644
--- a/compiler/cgmeth.nim
+++ b/compiler/cgmeth.nim
@@ -123,7 +123,7 @@ proc createDispatcher(s: PSym; g: ModuleGraph; idgen: IdGenerator): PSym =
   if disp.typ.callConv == ccInline: disp.typ.callConv = ccNimCall
   disp.ast = copyTree(s.ast)
   disp.ast[bodyPos] = newNodeI(nkEmpty, s.info)
-  disp.loc.r = nil
+  disp.loc.r = ""
   if s.typ[0] != nil:
     if disp.ast.len > resultPos:
       disp.ast[resultPos].sym = copySym(s.ast[resultPos].sym, nextSymId(idgen))
diff --git a/compiler/depends.nim b/compiler/depends.nim
index 7e5dabbd3332f..93f34dc7c7b8e 100644
--- a/compiler/depends.nim
+++ b/compiler/depends.nim
@@ -13,7 +13,8 @@ import options, ast, ropes, passes, pathutils, msgs, lineinfos
 
 import modulegraphs
 
-import std/[os, strutils, parseutils]
+import std/[os, parseutils]
+import strutils except addf
 import std/private/globs
 
 when defined(nimPreviewSlimSystem):
@@ -109,7 +110,7 @@ proc myOpen(graph: ModuleGraph; module: PSym; idgen: IdGenerator): PPassContext
   g.config = graph.config
   g.graph = graph
   if graph.backend == nil:
-    graph.backend = Backend(dotGraph: nil)
+    graph.backend = Backend(dotGraph: "")
   result = g
 
 const gendependPass* = makePass(open = myOpen, process = addDotDependency)
diff --git a/compiler/extccomp.nim b/compiler/extccomp.nim
index be79bb398ec38..0128ff3cbdb8d 100644
--- a/compiler/extccomp.nim
+++ b/compiler/extccomp.nim
@@ -14,7 +14,9 @@
 
 import ropes, platform, condsyms, options, msgs, lineinfos, pathutils, modulepaths
 
-import std/[os, strutils, osproc, sha1, streams, sequtils, times, strtabs, json, jsonutils, sugar, parseutils]
+import std/[os, osproc, sha1, streams, sequtils, times, strtabs, json, jsonutils, sugar, parseutils]
+
+import std / strutils except addf
 
 when defined(nimPreviewSlimSystem):
   import std/syncio
@@ -616,7 +618,7 @@ proc getCompileCFileCmd*(conf: ConfigRef; cfile: Cfile,
           "for the selected C compiler: " & CC[conf.cCompiler].name)
 
   result.add(' ')
-  result.addf(CC[c].compileTmpl, [
+  strutils.addf(result, CC[c].compileTmpl, [
     "dfile", dfile,
     "file", cfsh, "objfile", quoteShell(objfile),
     "options", options, "include", includeCmd,
@@ -707,7 +709,7 @@ proc getLinkCmd(conf: ConfigRef; output: AbsoluteFile,
         "buildgui", buildgui, "options", linkOptions, "objfiles", objfiles,
         "exefile", exefile, "nim", getPrefixDir(conf).string, "lib", conf.libpath.string])
     result.add ' '
-    result.addf(linkTmpl, ["builddll", builddll,
+    strutils.addf(result, linkTmpl, ["builddll", builddll,
         "mapfile", mapfile,
         "buildgui", buildgui, "options", linkOptions,
         "objfiles", objfiles, "exefile", exefile,
@@ -856,7 +858,7 @@ proc callCCompiler*(conf: ConfigRef) =
     return # speed up that call if only compiling and no script shall be
            # generated
   #var c = cCompiler
-  var script: Rope = nil
+  var script: Rope = ""
   var cmds: TStringSeq
   var prettyCmds: TStringSeq
   let prettyCb = proc (idx: int) = writePrettyCmdsStderr(prettyCmds[idx])
diff --git a/compiler/ic/ic.nim b/compiler/ic/ic.nim
index 2ac441b3ef861..866237f08368b 100644
--- a/compiler/ic/ic.nim
+++ b/compiler/ic/ic.nim
@@ -403,7 +403,7 @@ proc storeSym*(s: PSym; c: var PackedEncoder; m: var PackedModule): PackedItemId
       p.bitsize = s.bitsize
       p.alignment = s.alignment
 
-    p.externalName = toLitId(if s.loc.r.isNil: "" else: $s.loc.r, m)
+    p.externalName = toLitId(s.loc.r, m)
     p.locFlags = s.loc.flags
     c.addMissing s.typ
     p.typ = s.typ.storeType(c, m)
diff --git a/compiler/jsgen.nim b/compiler/jsgen.nim
index f3477cd48cf54..1a37ab7cf7783 100644
--- a/compiler/jsgen.nim
+++ b/compiler/jsgen.nim
@@ -35,7 +35,8 @@ import
   cgmeth, lowerings, sighashes, modulegraphs, lineinfos, rodutils,
   transf, injectdestructors, sourcemap, astmsgs
 
-import json, sets, math, tables, intsets, strutils
+import json, sets, math, tables, intsets
+import strutils except addf
 
 when defined(nimPreviewSlimSystem):
   import std/[assertions, syncio]
@@ -110,21 +111,18 @@ type
 template config*(p: PProc): ConfigRef = p.module.config
 
 proc indentLine(p: PProc, r: Rope): Rope =
-  result = r
   var p = p
+  var ind = 0
   while true:
-    for i in 0..<p.blocks.len + p.extraIndent:
-      prepend(result, rope"  ")
+    inc ind, p.blocks.len + p.extraIndent
     if p.up == nil or p.up.prc != p.prc.owner:
       break
     p = p.up
+  result = repeat(' ', ind*2) & r
 
 template line(p: PProc, added: string) =
   p.body.add(indentLine(p, rope(added)))
 
-template line(p: PProc, added: Rope) =
-  p.body.add(indentLine(p, added))
-
 template lineF(p: PProc, frmt: FormatStr, args: varargs[Rope]) =
   p.body.add(indentLine(p, ropes.`%`(frmt, args)))
 
@@ -140,9 +138,9 @@ proc newGlobals(): PGlobals =
   result.typeInfoGenerated = initIntSet()
 
 proc initCompRes(r: var TCompRes) =
-  r.address = nil
-  r.res = nil
-  r.tmpLoc = nil
+  r.address = ""
+  r.res = ""
+  r.tmpLoc = ""
   r.typ = etyNone
   r.kind = resNone
 
@@ -241,7 +239,7 @@ proc mangleName(m: BModule, s: PSym): Rope =
       if chr notin {'A'..'Z','a'..'z','_','$','0'..'9'}:
         return false
   result = s.loc.r
-  if result == nil:
+  if result == "":
     if s.kind == skField and s.name.s.validJsName:
       result = rope(s.name.s)
     elif s.kind == skTemp:
@@ -464,7 +462,7 @@ proc maybeMakeTemp(p: PProc, n: PNode; x: TCompRes): tuple[a, tmp: Rope] =
     b = a
   if needsTemp(p, n):
     # if we have tmp just use it
-    if x.tmpLoc != nil and (mapType(n.typ) == etyBaseIndex or n.kind in {nkHiddenDeref, nkDerefExpr}):
+    if x.tmpLoc != "" and (mapType(n.typ) == etyBaseIndex or n.kind in {nkHiddenDeref, nkDerefExpr}):
       b = "$1[0][$1[1]]" % [x.tmpLoc]
       (a: a, tmp: b)
     else:
@@ -481,10 +479,10 @@ proc maybeMakeTempAssignable(p: PProc, n: PNode; x: TCompRes): tuple[a, tmp: Rop
     b = a
   if needsTemp(p, n):
     # if we have tmp just use it
-    if x.tmpLoc != nil and (mapType(n.typ) == etyBaseIndex or n.kind in {nkHiddenDeref, nkDerefExpr}):
+    if x.tmpLoc != "" and (mapType(n.typ) == etyBaseIndex or n.kind in {nkHiddenDeref, nkDerefExpr}):
       b = "$1[0][$1[1]]" % [x.tmpLoc]
       result = (a: a, tmp: b)
-    elif x.tmpLoc != nil and n.kind == nkBracketExpr:
+    elif x.tmpLoc != "" and n.kind == nkBracketExpr:
       # genArrayAddr
       var
         address, index: TCompRes
@@ -745,7 +743,7 @@ proc moveInto(p: PProc, src: var TCompRes, dest: TCompRes) =
     else:
       lineF(p, "$1;$n", [src.rdLoc])
     src.kind = resNone
-    src.res = nil
+    src.res = ""
 
 proc genTry(p: PProc, n: PNode, r: var TCompRes) =
   # code to generate:
@@ -800,7 +798,7 @@ proc genTry(p: PProc, n: PNode, r: var TCompRes) =
       moveInto(p, a, r)
       if i > 1: lineF(p, "}$n", [])
     else:
-      var orExpr: Rope = nil
+      var orExpr: Rope = ""
       var excAlias: PNode = nil
 
       useMagic(p, "isObj")
@@ -813,13 +811,13 @@ proc genTry(p: PProc, n: PNode, r: var TCompRes) =
           excAlias = it[2]
           # If this is a ``except exc as sym`` branch there must be no following
           # nodes
-          doAssert orExpr == nil
+          doAssert orExpr == ""
         elif it.kind == nkType:
           throwObj = it
         else:
           internalError(p.config, n.info, "genTryStmt")
 
-        if orExpr != nil: orExpr.add("||")
+        if orExpr != "": orExpr.add("||")
         # Generate the correct type checking code depending on whether this is a
         # NIM-native or a JS-native exception
         # if isJsObject(throwObj.typ):
@@ -907,7 +905,7 @@ proc genCaseJS(p: PProc, n: PNode, r: var TCompRes) =
             gen(p, e[1], b)
             if j != itLen - 2:
               lineF(p, "$1 >= $2 && $1 <= $3 || $n", [cond.rdLoc, a.rdLoc, b.rdLoc])
-            else: 
+            else:
               lineF(p, "$1 >= $2 && $1 <= $3", [cond.rdLoc, a.rdLoc, b.rdLoc])
           else:
             var v = copyNode(e[0])
@@ -998,7 +996,7 @@ proc genBreakStmt(p: PProc, n: PNode) =
 
 proc genAsmOrEmitStmt(p: PProc, n: PNode) =
   genLineDir(p, n)
-  p.body.add p.indentLine(nil)
+  p.body.add p.indentLine("")
   for i in 0..<n.len:
     let it = n[i]
     case it.kind
@@ -1016,12 +1014,12 @@ proc genAsmOrEmitStmt(p: PProc, n: PNode) =
         if it.typ.kind == tyPointer:
           # A fat pointer is disguised as an array
           r.res = r.address
-          r.address = nil
+          r.address = ""
           r.typ = etyNone
         elif r.typ == etyBaseIndex:
           # Deference first
           r.res = "$1[$2]" % [r.address, r.res]
-          r.address = nil
+          r.address = ""
           r.typ = etyNone
 
         p.body.add(r.rdLoc)
@@ -1055,12 +1053,12 @@ proc genIf(p: PProc, n: PNode, r: var TCompRes) =
   line(p, repeat('}', toClose) & "\L")
 
 proc generateHeader(p: PProc, typ: PType): Rope =
-  result = nil
+  result = ""
   for i in 1..<typ.n.len:
     assert(typ.n[i].kind == nkSym)
     var param = typ.n[i].sym
     if isCompileTimeOnly(param.typ): continue
-    if result != nil: result.add(", ")
+    if result != "": result.add(", ")
     var name = mangleName(p.module, param)
     result.add(name)
     if mapType(param.typ) == etyBaseIndex:
@@ -1135,7 +1133,7 @@ proc genAsgnAux(p: PProc, x, y: PNode, noCopyNeeded: bool) =
       elif b.typ == etyBaseIndex:
         lineF(p, "$# = [$#, $#];$n", [a.res, b.address, b.res])
       elif b.typ == etyNone:
-        internalAssert p.config, b.address == nil
+        internalAssert p.config, b.address == ""
         lineF(p, "$# = [$#, 0];$n", [a.address, b.res])
       elif x.typ.kind == tyVar and y.typ.kind == tyPtr:
         lineF(p, "$# = [$#, $#];$n", [a.res, b.address, b.res])
@@ -1143,13 +1141,13 @@ proc genAsgnAux(p: PProc, x, y: PNode, noCopyNeeded: bool) =
         lineF(p, "$1 = $2;$n", [a.rdLoc, b.rdLoc])
       elif a.typ == etyBaseIndex:
         # array indexing may not map to var type
-        if b.address != nil:
+        if b.address != "":
           lineF(p, "$1 = $2; $3 = $4;$n", [a.address, b.address, a.res, b.res])
         else:
           lineF(p, "$1 = $2;$n", [a.address, b.res])
       else:
         internalError(p.config, x.info, $("genAsgn", b.typ, a.typ))
-    elif b.address != nil:
+    elif b.address != "":
       lineF(p, "$1 = $2; $3 = $4;$n", [a.address, b.address, a.res, b.res])
     else:
       lineF(p, "$1 = $2;$n", [a.address, b.res])
@@ -1201,7 +1199,7 @@ proc genFieldAddr(p: PProc, n: PNode, r: var TCompRes) =
   else:
     if b[1].kind != nkSym: internalError(p.config, b[1].info, "genFieldAddr")
     var f = b[1].sym
-    if f.loc.r == nil: f.loc.r = mangleName(p.module, f)
+    if f.loc.r == "": f.loc.r = mangleName(p.module, f)
     r.res = makeJSString($f.loc.r)
   internalAssert p.config, a.typ != etyBaseIndex
   r.address = a.res
@@ -1229,7 +1227,7 @@ proc genFieldAccess(p: PProc, n: PNode, r: var TCompRes) =
   else:
     if n[1].kind != nkSym: internalError(p.config, n[1].info, "genFieldAccess")
     var f = n[1].sym
-    if f.loc.r == nil: f.loc.r = mangleName(p.module, f)
+    if f.loc.r == "": f.loc.r = mangleName(p.module, f)
     r.res = "$1.$2" % [r.res, f.loc.r]
     mkTemp(1)
   r.kind = resExpr
@@ -1250,11 +1248,11 @@ proc genCheckedFieldOp(p: PProc, n: PNode, addrTyp: PType, r: var TCompRes) =
   # Field symbol
   var field = accessExpr[1].sym
   internalAssert p.config, field.kind == skField
-  if field.loc.r == nil: field.loc.r = mangleName(p.module, field)
+  if field.loc.r == "": field.loc.r = mangleName(p.module, field)
   # Discriminant symbol
   let disc = checkExpr[2].sym
   internalAssert p.config, disc.kind == skField
-  if disc.loc.r == nil: disc.loc.r = mangleName(p.module, disc)
+  if disc.loc.r == "": disc.loc.r = mangleName(p.module, disc)
 
   var setx: TCompRes
   gen(p, checkExpr[1], setx)
@@ -1271,7 +1269,7 @@ proc genCheckedFieldOp(p: PProc, n: PNode, addrTyp: PType, r: var TCompRes) =
   useMagic(p, "reprDiscriminant") # no need to offset by firstOrd unlike for cgen
   let msg = genFieldDefect(p.config, field.name.s, disc)
   lineF(p, "if ($1[$2.$3]$4undefined) { raiseFieldError2(makeNimstrLit($5), reprDiscriminant($2.$3, $6)); }$n",
-    setx.res, tmp, disc.loc.r, if negCheck: ~"!==" else: ~"===",
+    setx.res, tmp, disc.loc.r, if negCheck: "!==" else: "===",
     makeJSString(msg), genTypeInfo(p, disc.typ))
 
   if addrTyp != nil and mapType(p, addrTyp) == etyBaseIndex:
@@ -1320,7 +1318,7 @@ proc genArrayAccess(p: PProc, n: PNode, r: var TCompRes) =
     genFieldAddr(p, n, r)
   else: internalError(p.config, n.info, "expr(nkBracketExpr, " & $ty.kind & ')')
   r.typ = mapType(n.typ)
-  if r.res == nil: internalError(p.config, n.info, "genArrayAccess")
+  if r.res == "": internalError(p.config, n.info, "genArrayAccess")
   if ty.kind == tyCstring:
     r.res = "$1.charCodeAt($2)" % [r.address, r.res]
   elif r.typ == etyBaseIndex:
@@ -1347,11 +1345,11 @@ template isIndirect(x: PSym): bool =
 
 proc genSymAddr(p: PProc, n: PNode, typ: PType, r: var TCompRes) =
   let s = n.sym
-  if s.loc.r == nil: internalError(p.config, n.info, "genAddr: 3")
+  if s.loc.r == "": internalError(p.config, n.info, "genAddr: 3")
   case s.kind
   of skParam:
     r.res = s.loc.r
-    r.address = nil
+    r.address = ""
     r.typ = etyNone
   of skVar, skLet, skResult:
     r.kind = resExpr
@@ -1367,7 +1365,7 @@ proc genSymAddr(p: PProc, n: PNode, typ: PType, r: var TCompRes) =
         r.res = s.loc.r & "[0]"
       else:
         r.res = s.loc.r
-      r.address = nil
+      r.address = ""
     elif {sfGlobal, sfAddrTaken} * s.flags != {} or jsType == etyBaseIndex:
       # for ease of code generation, we do not distinguish between
       # sfAddrTaken and sfGlobal.
@@ -1466,7 +1464,7 @@ proc genSym(p: PProc, n: PNode, r: var TCompRes) =
   var s = n.sym
   case s.kind
   of skVar, skLet, skParam, skTemp, skResult, skForVar:
-    if s.loc.r == nil:
+    if s.loc.r == "":
       internalError(p.config, n.info, "symbol has no generated name: " & s.name.s)
     if sfCompileTime in s.flags:
       genVarInit(p, s, if s.ast != nil: s.ast else: newNodeI(nkEmpty, s.info))
@@ -1491,7 +1489,7 @@ proc genSym(p: PProc, n: PNode, r: var TCompRes) =
       r.res = s.loc.r
   of skConst:
     genConstant(p, s)
-    if s.loc.r == nil:
+    if s.loc.r == "":
       internalError(p.config, n.info, "symbol has no generated name: " & s.name.s)
     r.res = s.loc.r
   of skProc, skFunc, skConverter, skMethod:
@@ -1511,7 +1509,7 @@ proc genSym(p: PProc, n: PNode, r: var TCompRes) =
     else:
       genProcForSymIfNeeded(p, s)
   else:
-    if s.loc.r == nil:
+    if s.loc.r == "":
       internalError(p.config, n.info, "symbol has no generated name: " & s.name.s)
     if mapType(p, s.typ) == etyBaseIndex:
       r.address = s.loc.r
@@ -1536,7 +1534,7 @@ proc genDeref(p: PProc, n: PNode, r: var TCompRes) =
       r.res = "$1[1]" % [tmp]
       r.tmpLoc = tmp
     elif a.typ == etyBaseIndex:
-      if a.tmpLoc != nil:
+      if a.tmpLoc != "":
         r.tmpLoc = a.tmpLoc
       r.res = a.rdLoc
     else:
@@ -1659,9 +1657,9 @@ proc genPatternCall(p: PProc; n: PNode; pat: string; typ: PType;
 proc genInfixCall(p: PProc, n: PNode, r: var TCompRes) =
   # don't call '$' here for efficiency:
   let f = n[0].sym
-  if f.loc.r == nil: f.loc.r = mangleName(p.module, f)
+  if f.loc.r == "": f.loc.r = mangleName(p.module, f)
   if sfInfixCall in f.flags:
-    let pat = n[0].sym.loc.r.data
+    let pat = $n[0].sym.loc.r
     internalAssert p.config, pat.len > 0
     if pat.contains({'#', '(', '@'}):
       var typ = skipTypes(n[0].typ, abstractInst)
@@ -1671,10 +1669,10 @@ proc genInfixCall(p: PProc, n: PNode, r: var TCompRes) =
   if n.len != 1:
     gen(p, n[1], r)
     if r.typ == etyBaseIndex:
-      if r.address == nil:
+      if r.address == "":
         globalError(p.config, n.info, "cannot invoke with infix syntax")
       r.res = "$1[$2]" % [r.address, r.res]
-      r.address = nil
+      r.address = ""
       r.typ = etyNone
     r.res.add(".")
   var op: TCompRes
@@ -1826,12 +1824,12 @@ proc createVar(p: PProc, typ: PType, indirect: bool): Rope =
       result = createVar(p, lastSon t, indirect)
     else:
       internalError(p.config, "createVar: " & $t.kind)
-      result = nil
+      result = ""
   else:
     internalError(p.config, "createVar: " & $t.kind)
-    result = nil
+    result = ""
 
-template returnType: untyped = ~""
+template returnType: untyped = ""
 
 proc genVarInit(p: PProc, v: PSym, n: PNode) =
   var
@@ -1929,8 +1927,7 @@ proc genVarStmt(p: PProc, n: PNode) =
 
 proc genConstant(p: PProc, c: PSym) =
   if lfNoDecl notin c.loc.flags and not p.g.generatedSyms.containsOrIncl(c.id):
-    let oldBody = p.body
-    p.body = nil
+    let oldBody = move p.body
     #genLineDir(p, c.ast)
     genVarInit(p, c, c.ast)
     p.g.constants.add(p.body)
@@ -1984,7 +1981,7 @@ proc genConStrStr(p: PProc, n: PNode, r: var TCompRes) =
   else:
     r.res.add("$1 || [])" % [a.res])
 
-proc genReprAux(p: PProc, n: PNode, r: var TCompRes, magic: string, typ: Rope = nil) =
+proc genReprAux(p: PProc, n: PNode, r: var TCompRes, magic: string, typ: Rope = "") =
   useMagic(p, magic)
   r.res.add(magic & "(")
   var a: TCompRes
@@ -1993,7 +1990,7 @@ proc genReprAux(p: PProc, n: PNode, r: var TCompRes, magic: string, typ: Rope =
   if magic == "reprAny":
     # the pointer argument in reprAny is expandend to
     # (pointedto, pointer), so we need to fill it
-    if a.address.isNil:
+    if a.address.len == 0:
       r.res.add(a.res)
       r.res.add(", null")
     else:
@@ -2001,14 +1998,14 @@ proc genReprAux(p: PProc, n: PNode, r: var TCompRes, magic: string, typ: Rope =
   else:
     r.res.add(a.res)
 
-  if not typ.isNil:
+  if typ != "":
     r.res.add(", ")
     r.res.add(typ)
   r.res.add(")")
 
 proc genRepr(p: PProc, n: PNode, r: var TCompRes) =
   let t = skipTypes(n[1].typ, abstractVarRange)
-  case t.kind:
+  case t.kind
   of tyInt..tyInt64, tyUInt..tyUInt64:
     genReprAux(p, n, r, "reprInt")
   of tyChar:
@@ -2327,7 +2324,7 @@ proc genObjConstr(p: PProc, n: PNode, r: var TCompRes) =
     let val = it[1]
     gen(p, val, a)
     var f = it[0].sym
-    if f.loc.r == nil: f.loc.r = mangleName(p.module, f)
+    if f.loc.r == "": f.loc.r = mangleName(p.module, f)
     fieldIDs.incl(lookupFieldAgain(nTyp, f).id)
 
     let typ = val.typ.skipTypes(abstractInst)
@@ -2388,7 +2385,7 @@ proc convStrToCStr(p: PProc, n: PNode, r: var TCompRes) =
     gen(p, n[0][0], r)
   else:
     gen(p, n[0], r)
-    if r.res == nil: internalError(p.config, n.info, "convStrToCStr")
+    if r.res == "": internalError(p.config, n.info, "convStrToCStr")
     useMagic(p, "toJSStr")
     r.res = "toJSStr($1)" % [r.res]
     r.kind = resExpr
@@ -2400,7 +2397,7 @@ proc convCStrToStr(p: PProc, n: PNode, r: var TCompRes) =
     gen(p, n[0][0], r)
   else:
     gen(p, n[0], r)
-    if r.res == nil: internalError(p.config, n.info, "convCStrToStr")
+    if r.res == "": internalError(p.config, n.info, "convCStrToStr")
     useMagic(p, "cstrToNimstr")
     r.res = "cstrToNimstr($1)" % [r.res]
     r.kind = resExpr
@@ -2430,11 +2427,11 @@ proc genProcBody(p: PProc, prc: PSym): Rope =
               makeJSString(prc.owner.name.s & '.' & prc.name.s),
               makeJSString(toFilenameOption(p.config, prc.info.fileIndex, foStacktrace)))
   else:
-    result = nil
+    result = ""
   if p.beforeRetNeeded:
-    result.add p.indentLine(~"BeforeRet: {$n")
+    result.add p.indentLine("BeforeRet: {\n")
     result.add p.body
-    result.add p.indentLine(~"};$n")
+    result.add p.indentLine("};\n")
   else:
     result.add(p.body)
   if prc.typ.callConv == ccSysCall:
@@ -2444,8 +2441,8 @@ proc genProcBody(p: PProc, prc: PSym): Rope =
     result.add(frameDestroy(p))
 
 proc optionalLine(p: Rope): Rope =
-  if p == nil:
-    return nil
+  if p == "":
+    return ""
   else:
     return p & "\L"
 
@@ -2458,8 +2455,8 @@ proc genProc(oldProc: PProc, prc: PSym): Rope =
   #  echo "BEGIN generating code for: " & prc.name.s
   var p = newProc(oldProc.g, oldProc.module, prc.ast, prc.options)
   p.up = oldProc
-  var returnStmt: Rope = nil
-  var resultAsgn: Rope = nil
+  var returnStmt: Rope = ""
+  var resultAsgn: Rope = ""
   var name = mangleName(p.module, prc)
   let header = generateHeader(p, prc.typ)
   if prc.typ[0] != nil and sfPure notin prc.flags:
@@ -2503,7 +2500,7 @@ proc genProc(oldProc: PProc, prc: PSym): Rope =
               optionalLine(p.indentLine(returnStmt))])
   else:
     # if optLineDir in p.config.options:
-      # result.add(~"\L")
+      # result.add("\L")
 
     if p.config.hcrOn:
       # Here, we introduce thunks that create the equivalent of a jump table
@@ -2526,7 +2523,7 @@ proc genProc(oldProc: PProc, prc: PSym): Rope =
 
   dec p.extraIndent
   result.add p.indentLine(def)
-  result.add p.indentLine(~"}$n")
+  result.add p.indentLine("}\n")
 
   #if gVerbosity >= 3:
   #  echo "END   generated code for: " & prc.name.s
@@ -2534,7 +2531,7 @@ proc genProc(oldProc: PProc, prc: PSym): Rope =
 proc genStmt(p: PProc, n: PNode) =
   var r: TCompRes
   gen(p, n, r)
-  if r.res != nil: lineF(p, "$#;$n", [r.res])
+  if r.res != "": lineF(p, "$#;$n", [r.res])
 
 proc genPragma(p: PProc, n: PNode) =
   for it in n.sons:
@@ -2574,7 +2571,7 @@ proc genCast(p: PProc, n: PNode, r: var TCompRes) =
         r.res = "($1 - ($2 $3))" % [rope minuend, r.res, trimmer]
   elif (src.kind == tyPtr and mapType(p, src) == etyObject) and dest.kind == tyPointer:
     r.address = r.res
-    r.res = ~"null"
+    r.res = "null"
     r.typ = etyBaseIndex
   elif (dest.kind == tyPtr and mapType(p, dest) == etyObject) and src.kind == tyPointer:
     r.res = r.address
@@ -2583,8 +2580,8 @@ proc genCast(p: PProc, n: PNode, r: var TCompRes) =
 proc gen(p: PProc, n: PNode, r: var TCompRes) =
   r.typ = etyNone
   if r.kind != resCallee: r.kind = resNone
-  #r.address = nil
-  r.res = nil
+  #r.address = ""
+  r.res = ""
 
   case n.kind
   of nkSym:
@@ -2723,7 +2720,7 @@ proc gen(p: PProc, n: PNode, r: var TCompRes) =
     var s = n[namePos].sym
     if {sfExportc, sfCompilerProc} * s.flags == {sfExportc}:
       genSym(p, n[namePos], r)
-      r.res = nil
+      r.res = ""
   of nkGotoState, nkState:
     globalError(p.config, n.info, "First class iterators not implemented")
   of nkPragmaBlock: gen(p, n.lastSon, r)
@@ -2840,7 +2837,7 @@ proc getClassName(t: PType): Rope =
     s = skipTypes(t, abstractPtrs).sym
   if s.isNil or sfAnon in s.flags:
     doAssert(false, "cannot retrieve class name")
-  if s.loc.r != nil: result = s.loc.r
+  if s.loc.r != "": result = s.loc.r
   else: result = rope(s.name.s)
 
 proc myClose(graph: ModuleGraph; b: PPassContext, n: PNode): PNode =
diff --git a/compiler/jstypes.nim b/compiler/jstypes.nim
index 5b684b60c0b25..56d075af72b8e 100644
--- a/compiler/jstypes.nim
+++ b/compiler/jstypes.nim
@@ -19,13 +19,13 @@ proc genObjectFields(p: PProc, typ: PType, n: PNode): Rope =
     s, u: Rope
     field: PSym
     b: PNode
-  result = nil
+  result = ""
   case n.kind
   of nkRecList:
     if n.len == 1:
       result = genObjectFields(p, typ, n[0])
     else:
-      s = nil
+      s = ""
       for i in 0..<n.len:
         if i > 0: s.add(", \L")
         s.add(genObjectFields(p, typ, n[i]))
@@ -44,13 +44,13 @@ proc genObjectFields(p: PProc, typ: PType, n: PNode): Rope =
     s = genTypeInfo(p, field.typ)
     for i in 1..<n.len:
       b = n[i]           # branch
-      u = nil
+      u = ""
       case b.kind
       of nkOfBranch:
         if b.len < 2:
           internalError(p.config, b.info, "genObjectFields; nkOfBranch broken")
         for j in 0..<b.len - 1:
-          if u != nil: u.add(", ")
+          if u != "": u.add(", ")
           if b[j].kind == nkRange:
             u.addf("[$1, $2]", [rope(getOrdValue(b[j][0])),
                                  rope(getOrdValue(b[j][1]))])
@@ -59,7 +59,7 @@ proc genObjectFields(p: PProc, typ: PType, n: PNode): Rope =
       of nkElse:
         u = rope(lengthOrd(p.config, field.typ))
       else: internalError(p.config, n.info, "genObjectFields(nkRecCase)")
-      if result != nil: result.add(", \L")
+      if result != "": result.add(", \L")
       result.addf("[setConstr($1), $2]",
            [u, genObjectFields(p, typ, lastSon(b))])
     result = ("{kind: 3, offset: \"$1\", len: $3, " &
@@ -84,7 +84,7 @@ proc genObjectInfo(p: PProc, typ: PType, name: Rope) =
          [name, genTypeInfo(p, typ[0].skipTypes(skipPtrs))])
 
 proc genTupleFields(p: PProc, typ: PType): Rope =
-  var s: Rope = nil
+  var s: Rope = ""
   for i in 0..<typ.len:
     if i > 0: s.add(", \L")
     s.addf("{kind: 1, offset: \"Field$1\", len: 0, " &
@@ -102,7 +102,7 @@ proc genTupleInfo(p: PProc, typ: PType, name: Rope) =
   p.g.typeInfo.addf("$1.node = NNI$2;$n", [name, rope(typ.id)])
 
 proc genEnumInfo(p: PProc, typ: PType, name: Rope) =
-  var s: Rope = nil
+  var s: Rope = ""
   for i in 0..<typ.n.len:
     if (typ.n[i].kind != nkSym): internalError(p.config, typ.n.info, "genEnumInfo")
     let field = typ.n[i].sym
diff --git a/compiler/msgs.nim b/compiler/msgs.nim
index 3b25da62a7cc2..c7610b630a24d 100644
--- a/compiler/msgs.nim
+++ b/compiler/msgs.nim
@@ -10,7 +10,9 @@
 import
   std/[strutils, os, tables, terminal, macros, times],
   std/private/miscdollars,
-  options, ropes, lineinfos, pathutils, strutils2
+  options, lineinfos, pathutils, strutils2
+
+import ropes except `%`
 
 when defined(nimPreviewSlimSystem):
   import std/[syncio, assertions]
@@ -43,18 +45,16 @@ proc toCChar*(c: char; result: var string) {.inline.} =
     result.add c
 
 proc makeCString*(s: string): Rope =
-  result = nil
-  var res = newStringOfCap(int(s.len.toFloat * 1.1) + 1)
-  res.add("\"")
+  result = newStringOfCap(int(s.len.toFloat * 1.1) + 1)
+  result.add("\"")
   for i in 0..<s.len:
     # line wrapping of string litterals in cgen'd code was a bad idea, e.g. causes: bug #16265
     # It also makes reading c sources or grepping harder, for zero benefit.
     # const MaxLineLength = 64
     # if (i + 1) mod MaxLineLength == 0:
     #   res.add("\"\L\"")
-    toCChar(s[i], res)
-  res.add('\"')
-  result.add(rope(res))
+    toCChar(s[i], result)
+  result.add('\"')
 
 proc newFileInfo(fullPath: AbsoluteFile, projPath: RelativeFile): TFileInfo =
   result.fullPath = fullPath
diff --git a/compiler/pragmas.nim b/compiler/pragmas.nim
index 101b17bf628d3..fdf4dd91fa1a3 100644
--- a/compiler/pragmas.nim
+++ b/compiler/pragmas.nim
@@ -960,7 +960,7 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
         incl(sym.loc.flags, lfHeader)
         incl(sym.loc.flags, lfNoDecl)
         # implies nodecl, because otherwise header would not make sense
-        if sym.loc.r == nil: sym.loc.r = rope(sym.name.s)
+        if sym.loc.r == "": sym.loc.r = rope(sym.name.s)
       of wNoSideEffect:
         noVal(c, it)
         if sym != nil:
@@ -1290,7 +1290,7 @@ proc implicitPragmas*(c: PContext, sym: PSym, info: TLineInfo,
         sfImportc in sym.flags and lib != nil:
       incl(sym.loc.flags, lfDynamicLib)
       addToLib(lib, sym)
-      if sym.loc.r == nil: sym.loc.r = rope(sym.name.s)
+      if sym.loc.r == "": sym.loc.r = rope(sym.name.s)
 
 proc hasPragma*(n: PNode, pragma: TSpecialWord): bool =
   if n == nil: return false
diff --git a/compiler/ropes.nim b/compiler/ropes.nim
index b84cfad527ed4..12eac733e7d97 100644
--- a/compiler/ropes.nim
+++ b/compiler/ropes.nim
@@ -7,217 +7,57 @@
 #    distribution, for details about the copyright.
 #
 
-# Ropes for the C code generator
-#
-#  Ropes are a data structure that represents a very long string
-#  efficiently; especially concatenation is done in O(1) instead of O(N).
-#  Ropes make use a lazy evaluation: They are essentially concatenation
-#  trees that are only flattened when converting to a native Nim
-#  string or when written to disk. The empty string is represented by a
-#  nil pointer.
-#  A little picture makes everything clear:
-#
-#  "this string" & " is internally " & "represented as"
-#
-#             con  -- inner nodes do not contain raw data
-#            /   \
-#           /     \
-#          /       \
-#        con       "represented as"
-#       /   \
-#      /     \
-#     /       \
-#    /         \
-#   /           \
-#"this string"  " is internally "
-#
-#  Note that this is the same as:
-#  "this string" & (" is internally " & "represented as")
-#
-#             con
-#            /   \
-#           /     \
-#          /       \
-# "this string"    con
-#                 /   \
-#                /     \
-#               /       \
-#              /         \
-#             /           \
-#" is internally "        "represented as"
-#
-#  The 'con' operator is associative! This does not matter however for
-#  the algorithms we use for ropes.
-#
-#  Note that the left and right pointers are not needed for leaves.
-#  Leaves have relatively high memory overhead (~30 bytes on a 32
-#  bit machines) and we produce many of them. This is why we cache and
-#  share leaves across different rope trees.
-#  To cache them they are inserted in a `cache` array.
+# Ropes for the C code generator. Ropes are mapped to `string` directly nowadays.
 
-import
-  hashes
+import hashes
 
 from pathutils import AbsoluteFile
 
 when defined(nimPreviewSlimSystem):
   import std/[assertions, syncio, formatfloat]
 
-
 type
   FormatStr* = string  # later we may change it to CString for better
                        # performance of the code generator (assignments
                        # copy the format strings
                        # though it is not necessary)
-  Rope* = ref RopeObj
-  RopeObj*{.acyclic.} = object of RootObj # the empty rope is represented
-                                          # by nil to safe space
-    left, right: Rope
-    L: int                    # <= 0 if a leaf
-    data*: string
+  Rope* = string
 
-proc len*(a: Rope): int =
-  ## the rope's length
-  if a == nil: result = 0
-  else: result = abs a.L
+proc newRopeAppender*(): string {.inline.} =
+  result = newString(0)
 
-proc newRope(data: string = ""): Rope =
-  new(result)
-  result.L = -data.len
-  result.data = data
-
-when compileOption("tlsEmulation"): # fixme: be careful if you want to make ropes support multiple threads
-  var
-    cache: array[0..2048*2 - 1, Rope]
-else:
-  var
-    cache {.threadvar.} : array[0..2048*2 - 1, Rope]
-
-proc resetRopeCache* =
-  for i in low(cache)..high(cache):
-    cache[i] = nil
-
-proc ropeInvariant(r: Rope): bool =
-  if r == nil:
-    result = true
-  else:
-    result = true #
-                  #    if r.data <> snil then
-                  #      result := true
-                  #    else begin
-                  #      result := (r.left <> nil) and (r.right <> nil);
-                  #      if result then result := ropeInvariant(r.left);
-                  #      if result then result := ropeInvariant(r.right);
-                  #    end
+proc freeze*(r: Rope) {.inline.} = discard
 
-var gCacheTries* = 0
-var gCacheMisses* = 0
-var gCacheIntTries* = 0
+proc resetRopeCache* = discard
 
-proc insertInCache(s: string): Rope =
-  inc gCacheTries
-  var h = hash(s) and high(cache)
-  result = cache[h]
-  if isNil(result) or result.data != s:
-    inc gCacheMisses
-    result = newRope(s)
-    cache[h] = result
-
-proc rope*(s: string): Rope =
-  ## Converts a string to a rope.
-  if s.len == 0:
-    result = nil
-  else:
-    result = insertInCache(s)
-  assert(ropeInvariant(result))
+template rope*(s: string): string = s
 
 proc rope*(i: BiggestInt): Rope =
   ## Converts an int to a rope.
-  inc gCacheIntTries
   result = rope($i)
 
 proc rope*(f: BiggestFloat): Rope =
   ## Converts a float to a rope.
   result = rope($f)
 
-proc `&`*(a, b: Rope): Rope =
-  if a == nil:
-    result = b
-  elif b == nil:
-    result = a
-  else:
-    result = newRope()
-    result.L = abs(a.L) + abs(b.L)
-    result.left = a
-    result.right = b
-
-proc `&`*(a: Rope, b: string): Rope =
-  ## the concatenation operator for ropes.
-  result = a & rope(b)
-
-proc `&`*(a: string, b: Rope): Rope =
-  ## the concatenation operator for ropes.
-  result = rope(a) & b
-
-proc `&`*(a: openArray[Rope]): Rope =
-  ## the concatenation operator for an openarray of ropes.
-  for i in 0..high(a): result = result & a[i]
-
-proc add*(a: var Rope, b: Rope) =
-  ## adds `b` to the rope `a`.
-  a = a & b
-
-proc add*(a: var Rope, b: string) =
-  ## adds `b` to the rope `a`.
-  a = a & b
-
-iterator leaves*(r: Rope): string =
-  ## iterates over any leaf string in the rope `r`.
-  if r != nil:
-    var stack = @[r]
-    while stack.len > 0:
-      var it = stack.pop
-      while it.left != nil:
-        assert it.right != nil
-        stack.add(it.right)
-        it = it.left
-        assert(it != nil)
-      yield it.data
-
-iterator items*(r: Rope): char =
-  ## iterates over any character in the rope `r`.
-  for s in leaves(r):
-    for c in items(s): yield c
-
 proc writeRope*(f: File, r: Rope) =
   ## writes a rope to a file.
-  for s in leaves(r): write(f, s)
+  write(f, r)
 
 proc writeRope*(head: Rope, filename: AbsoluteFile): bool =
   var f: File
   if open(f, filename.string, fmWrite):
-    if head != nil: writeRope(f, head)
+    writeRope(f, head)
     close(f)
     result = true
   else:
     result = false
 
-proc `$`*(r: Rope): string =
-  ## converts a rope back to a string.
-  result = newString(r.len)
-  setLen(result, 0)
-  for s in leaves(r): result.add(s)
-
-proc ropeConcat*(a: varargs[Rope]): Rope =
-  # not overloaded version of concat to speed-up `rfmt` a little bit
-  for i in 0..high(a): result = result & a[i]
-
-proc prepend*(a: var Rope, b: Rope) = a = b & a
 proc prepend*(a: var Rope, b: string) = a = b & a
 
 proc runtimeFormat*(frmt: FormatStr, args: openArray[Rope]): Rope =
   var i = 0
-  result = nil
+  result = newRopeAppender()
   var num = 0
   while i < frmt.len:
     if frmt[i] == '$':
@@ -270,7 +110,6 @@ proc runtimeFormat*(frmt: FormatStr, args: openArray[Rope]): Rope =
       else: break
     if i - 1 >= start:
       result.add(substr(frmt, start, i - 1))
-  assert(ropeInvariant(result))
 
 proc `%`*(frmt: static[FormatStr], args: openArray[Rope]): Rope =
   runtimeFormat(frmt, args)
@@ -279,21 +118,10 @@ template addf*(c: var Rope, frmt: FormatStr, args: openArray[Rope]) =
   ## shortcut for ``add(c, frmt % args)``.
   c.add(frmt % args)
 
-when true:
-  template `~`*(r: string): Rope = r % []
-else:
-  {.push stack_trace: off, line_trace: off.}
-  proc `~`*(r: static[string]): Rope =
-    # this is the new optimized "to rope" operator
-    # the mnemonic is that `~` looks a bit like a rope :)
-    var r {.global.} = r % []
-    return r
-  {.pop.}
-
 const
   bufSize = 1024              # 1 KB is reasonable
 
-proc equalsFile*(r: Rope, f: File): bool =
+proc equalsFile*(s: Rope, f: File): bool =
   ## returns true if the contents of the file `f` equal `r`.
   var
     buf: array[bufSize, char]
@@ -302,7 +130,7 @@ proc equalsFile*(r: Rope, f: File): bool =
     btotal = 0
     rtotal = 0
 
-  for s in leaves(r):
+  when true:
     var spos = 0
     rtotal += s.len
     while spos < s.len:
diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index 39ee6134c6e83..90e2f2b236356 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -2259,7 +2259,7 @@ proc instantiateCreateFlowVarCall(c: PContext; t: PType;
   # codegen would fail:
   if sfCompilerProc in result.flags:
     result.flags.excl {sfCompilerProc, sfExportc, sfImportc}
-    result.loc.r = nil
+    result.loc.r = ""
 
 proc setMs(n: PNode, s: PSym): PNode =
   result = n
@@ -2836,7 +2836,7 @@ proc semExpr(c: PContext, n: PNode, flags: TExprFlags = {}, expectedType: PType
     defer:
       if isCompilerDebug():
         echo ("<", c.config$n.info, n, ?.result.typ)
-  
+
   template directLiteral(typeKind: TTypeKind) =
     if result.typ == nil:
       if expectedType != nil and (
diff --git a/compiler/semtypes.nim b/compiler/semtypes.nim
index 7d077ab5a6246..0a823f20ad6da 100644
--- a/compiler/semtypes.nim
+++ b/compiler/semtypes.nim
@@ -824,7 +824,7 @@ proc semRecordNodeAux(c: PContext, n: PNode, check: var IntSet, pos: var int,
       f.options = c.config.options
       if fieldOwner != nil and
          {sfImportc, sfExportc} * fieldOwner.flags != {} and
-         not hasCaseFields and f.loc.r == nil:
+         not hasCaseFields and f.loc.r == "":
         f.loc.r = rope(f.name.s)
         f.flags.incl {sfImportc, sfExportc} * fieldOwner.flags
       inc(pos)
diff --git a/compiler/sighashes.nim b/compiler/sighashes.nim
index 1835d9d0f7051..f58c9c3ef8050 100644
--- a/compiler/sighashes.nim
+++ b/compiler/sighashes.nim
@@ -21,8 +21,7 @@ proc `&=`(c: var MD5Context, s: string) = md5Update(c, s, s.len)
 proc `&=`(c: var MD5Context, ch: char) =
   # XXX suspicious code here; relies on ch being zero terminated?
   md5Update(c, unsafeAddr ch, 1)
-proc `&=`(c: var MD5Context, r: Rope) =
-  for l in leaves(r): md5Update(c, l.cstring, l.len)
+
 proc `&=`(c: var MD5Context, i: BiggestInt) =
   md5Update(c, cast[cstring](unsafeAddr i), sizeof(i))
 proc `&=`(c: var MD5Context, f: BiggestFloat) =
@@ -150,7 +149,7 @@ proc hashType(c: var MD5Context, t: PType; flags: set[ConsiderFlag]) =
     # is actually safe without an infinite recursion check:
     if t.sym != nil:
       if {sfCompilerProc} * t.sym.flags != {}:
-        doAssert t.sym.loc.r != nil
+        doAssert t.sym.loc.r != ""
         # The user has set a specific name for this type
         c &= t.sym.loc.r
       elif CoOwnerSig in flags: