remove keepAlive and friends

compiler/ccgcalls.nim

@@ -536,8 +536,6 @@ proc genCall(p: BProc, e: PNode, d: var TLoc) =
   else:
     genPrefixCall(p, nil, e, d)
   postStmtActions(p)
-  when false:
-    if d.s == onStack and containsGarbageCollectedRef(d.t): keepAlive(p, d)
 
 proc genAsgnCall(p: BProc, le, ri: PNode, d: var TLoc) =
   if ri.sons[0].typ.skipTypes({tyGenericInst}).callConv == ccClosure:
@@ -549,6 +547,3 @@ proc genAsgnCall(p: BProc, le, ri: PNode, d: var TLoc) =
   else:
     genPrefixCall(p, le, ri, d)
   postStmtActions(p)
-  when false:
-    if d.s == onStack and containsGarbageCollectedRef(d.t): keepAlive(p, d)
-

compiler/ccgexprs.nim

@@ -171,7 +171,6 @@ proc getStorageLoc(n: PNode): TStorageLoc =
 proc genRefAssign(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
   if dest.s == OnStack or not usesNativeGC():
     linefmt(p, cpsStmts, "$1 = $2;$n", rdLoc(dest), rdLoc(src))
-    if needToKeepAlive in flags: keepAlive(p, dest)
   elif dest.s == OnHeap:
     # location is on heap
     # now the writer barrier is inlined for performance:
@@ -198,7 +197,6 @@ proc genRefAssign(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
   else:
     linefmt(p, cpsStmts, "#unsureAsgnRef((void**) $1, $2);$n",
             addrLoc(dest), rdLoc(src))
-    if needToKeepAlive in flags: keepAlive(p, dest)
 
 proc asgnComplexity(n: PNode): int =
   if n != nil:
@@ -268,7 +266,6 @@ proc genGenericAsgn(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
       linefmt(p, cpsStmts,
            "memcpy((void*)$1, (NIM_CONST void*)$2, sizeof($3));$n",
            addrLoc(dest), addrLoc(src), rdLoc(dest))
-      if needToKeepAlive in flags: keepAlive(p, dest)
     else:
       linefmt(p, cpsStmts, "#genericShallowAssign((void*)$1, (void*)$2, $3);$n",
               addrLoc(dest), addrLoc(src), genTypeInfo(p.module, dest.t))
@@ -299,7 +296,6 @@ proc genAssignment(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
     else:
       if dest.s == OnStack or not usesNativeGC():
         linefmt(p, cpsStmts, "$1 = #copyString($2);$n", dest.rdLoc, src.rdLoc)
-        if needToKeepAlive in flags: keepAlive(p, dest)
       elif dest.s == OnHeap:
         # we use a temporary to care for the dreaded self assignment:
         var tmp: TLoc
@@ -310,7 +306,6 @@ proc genAssignment(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
       else:
         linefmt(p, cpsStmts, "#unsureAsgnRef((void**) $1, #copyString($2));$n",
                addrLoc(dest), rdLoc(src))
-        if needToKeepAlive in flags: keepAlive(p, dest)
   of tyProc:
     if needsComplexAssignment(dest.t):
       # optimize closure assignment:
@@ -1006,9 +1001,8 @@ proc genStrConcat(p: BProc, e: PNode, d: var TLoc) =
   add(p.s(cpsStmts), appends)
   if d.k == locNone:
     d = tmp
-    keepAlive(p, tmp)
   else:
-    genAssignment(p, d, tmp, {needToKeepAlive}) # no need for deep copying
+    genAssignment(p, d, tmp, {}) # no need for deep copying
   gcUsage(e)
 
 proc genStrAppend(p: BProc, e: PNode, d: var TLoc) =
@@ -1045,7 +1039,6 @@ proc genStrAppend(p: BProc, e: PNode, d: var TLoc) =
                         rdLoc(dest), rdLoc(a)))
   linefmt(p, cpsStmts, "$1 = #resizeString($1, $2$3);$n",
           rdLoc(dest), lens, rope(L))
-  keepAlive(p, dest)
   add(p.s(cpsStmts), appends)
   gcUsage(e)
 
@@ -1065,7 +1058,6 @@ proc genSeqElemAppend(p: BProc, e: PNode, d: var TLoc) =
       rdLoc(a),
       getTypeDesc(p.module, skipTypes(e.sons[1].typ, abstractVar)),
       getTypeDesc(p.module, bt)])
-  keepAlive(p, a)
   #if bt != b.t:
   #  echo "YES ", e.info, " new: ", typeToString(bt), " old: ", typeToString(b.t)
   initLoc(dest, locExpr, bt, OnHeap)
@@ -1092,7 +1084,7 @@ proc rawGenNew(p: BProc, a: TLoc, sizeExpr: Rope) =
               genTypeInfo(p.module, refType),
               sizeExpr]
   if a.s == OnHeap and usesNativeGC():
-    # use newObjRC1 as an optimization; and we don't need 'keepAlive' either
+    # use newObjRC1 as an optimization
     if canFormAcycle(a.t):
       linefmt(p, cpsStmts, "if ($1) #nimGCunref($1);$n", a.rdLoc)
     else:
@@ -1101,7 +1093,7 @@ proc rawGenNew(p: BProc, a: TLoc, sizeExpr: Rope) =
     linefmt(p, cpsStmts, "$1 = $2;$n", a.rdLoc, b.rdLoc)
   else:
     b.r = ropecg(p.module, "($1) #newObj($2, $3)", args)
-    genAssignment(p, a, b, {needToKeepAlive})  # set the object type:
+    genAssignment(p, a, b, {})  # set the object type:
   let bt = skipTypes(refType.sons[0], abstractRange)
   genObjectInit(p, cpsStmts, bt, a, false)
 
@@ -1132,7 +1124,7 @@ proc genNewSeqAux(p: BProc, dest: TLoc, length: Rope) =
     linefmt(p, cpsStmts, "$1 = $2;$n", dest.rdLoc, call.rdLoc)
   else:
     call.r = ropecg(p.module, "($1) #newSeq($2, $3)", args)
-    genAssignment(p, dest, call, {needToKeepAlive})
+    genAssignment(p, dest, call, {})
 
 proc genNewSeq(p: BProc, e: PNode) =
   var a, b: TLoc
@@ -1254,7 +1246,7 @@ proc genNewFinalize(p: BProc, e: PNode) =
   b.r = ropecg(p.module, "($1) #newObj($2, sizeof($3))", [
       getTypeDesc(p.module, refType),
       ti, getTypeDesc(p.module, skipTypes(refType.lastSon, abstractRange))])
-  genAssignment(p, a, b, {needToKeepAlive})  # set the object type:
+  genAssignment(p, a, b, {})  # set the object type:
   bt = skipTypes(refType.lastSon, abstractRange)
   genObjectInit(p, cpsStmts, bt, a, false)
   gcUsage(e)
@@ -1364,7 +1356,7 @@ proc genDollar(p: BProc, n: PNode, d: var TLoc, frmt: string) =
   initLocExpr(p, n.sons[1], a)
   a.r = ropecg(p.module, frmt, [rdLoc(a)])
   if d.k == locNone: getTemp(p, n.typ, d)
-  genAssignment(p, d, a, {needToKeepAlive})
+  genAssignment(p, d, a, {})
   gcUsage(n)
 
 proc genArrayLen(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
@@ -1406,12 +1398,10 @@ proc genSetLengthSeq(p: BProc, e: PNode, d: var TLoc) =
   lineCg(p, cpsStmts, setLenPattern, [
       rdLoc(a), rdLoc(b), getTypeDesc(p.module, t),
       getTypeDesc(p.module, t.sons[0])])
-  keepAlive(p, a)
   gcUsage(e)
 
 proc genSetLengthStr(p: BProc, e: PNode, d: var TLoc) =
   binaryStmt(p, e, d, "$1 = #setLengthStr($1, $2);$n")
-  keepAlive(p, d)
   gcUsage(e)
 
 proc genSwap(p: BProc, e: PNode, d: var TLoc) =
@@ -1719,10 +1709,7 @@ proc genMagicExpr(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
         getTypeDesc(p.module, ranged), res])
 
   of mConStrStr: genStrConcat(p, e, d)
-  of mAppendStrCh:
-    binaryStmt(p, e, d, "$1 = #addChar($1, $2);$n")
-    # strictly speaking we need to generate "keepAlive" here too, but this
-    # very likely not needed and would slow down the code too much I fear
+  of mAppendStrCh: binaryStmt(p, e, d, "$1 = #addChar($1, $2);$n")
   of mAppendStrStr: genStrAppend(p, e, d)
   of mAppendSeqElem: genSeqElemAppend(p, e, d)
   of mEqStr: genStrEquals(p, e, d)

compiler/cgen.nim

@@ -260,7 +260,7 @@ proc genObjectInit(p: BProc, section: TCProcSection, t: PType, a: TLoc,
 type
   TAssignmentFlag = enum
     needToCopy, needForSubtypeCheck, afDestIsNil, afDestIsNotNil, afSrcIsNil,
-    afSrcIsNotNil, needToKeepAlive
+    afSrcIsNotNil
   TAssignmentFlags = set[TAssignmentFlag]
 
 proc genRefAssign(p: BProc, dest, src: TLoc, flags: TAssignmentFlags)
@@ -338,31 +338,6 @@ proc getTemp(p: BProc, t: PType, result: var TLoc; needsInit=false) =
   result.flags = {}
   constructLoc(p, result, not needsInit)
 
-proc keepAlive(p: BProc, toKeepAlive: TLoc) =
-  when false:
-    # deactivated because of the huge slowdown this causes; GC will take care
-    # of interior pointers instead
-    if optRefcGC notin gGlobalOptions: return
-    var result: TLoc
-    var fid = rope(p.gcFrameId)
-    result.r = "GCFRAME.F" & fid
-    addf(p.gcFrameType, "  $1 F$2;$n",
-        [getTypeDesc(p.module, toKeepAlive.t), fid])
-    inc(p.gcFrameId)
-    result.k = locTemp
-    #result.a = -1
-    result.t = toKeepAlive.t
-    result.s = OnStack
-    result.flags = {}
-
-    if not isComplexValueType(skipTypes(toKeepAlive.t, abstractVarRange)):
-      linefmt(p, cpsStmts, "$1 = $2;$n", rdLoc(result), rdLoc(toKeepAlive))
-    else:
-      useStringh(p.module)
-      linefmt(p, cpsStmts,
-           "memcpy((void*)$1, (NIM_CONST void*)$2, sizeof($3));$n",
-           addrLoc(result), addrLoc(toKeepAlive), rdLoc(result))
-
 proc initGCFrame(p: BProc): Rope =
   if p.gcFrameId > 0: result = "struct {$1} GCFRAME;$n" % [p.gcFrameType]