first version of a simple mark&sweep GC; activate with --gc:markAndSweep

compiler/ccgstmts.nim

@@ -1,7 +1,7 @@
 #
 #
 #           The Nimrod Compiler
-#        (c) Copyright 2012 Andreas Rumpf
+#        (c) Copyright 2013 Andreas Rumpf
 #
 #    See the file "copying.txt", included in this
 #    distribution, for details about the copyright.
@@ -15,6 +15,14 @@ const
   stringCaseThreshold = 8
     # above X strings a hash-switch for strings is generated
 
+proc registerGcRoot(p: BProc, v: PSym) =
+  if gSelectedGc == gcMarkAndSweep 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 :-)
+    let prc = genTraverseProcForGlobal(p.module, v)
+    linefmt(p.module.initProc, cpsStmts,
+      "#nimRegisterGlobalMarker((void*)$1);$n", prc)
+
 proc genVarTuple(p: BProc, n: PNode) = 
   var tup, field: TLoc
   if n.kind != nkVarTuple: InternalError(n.info, "genVarTuple")
@@ -28,6 +36,7 @@ proc genVarTuple(p: BProc, n: PNode) =
     if sfGlobal in v.flags:
       assignGlobalVar(p, v)
       genObjectInit(p, cpsInit, v.typ, v.loc, true)
+      registerGcRoot(p, v)
     else:
       assignLocalVar(p, v)
       initLocalVar(p, v, immediateAsgn=true)
@@ -143,7 +152,7 @@ proc genSingleVar(p: BProc, a: PNode) =
     # if sfImportc notin v.flags: constructLoc(p.module.preInitProc, v.loc)
     if sfExportc in v.flags and generatedHeader != nil:
       genVarPrototypeAux(generatedHeader, v)
-
+    registerGcRoot(p, v)
   else:
     assignLocalVar(p, v)
     initLocalVar(p, v, immediateAsgn)

compiler/ccgtrav.nim

@@ -1,7 +1,7 @@
 #
 #
 #           The Nimrod Compiler
-#        (c) Copyright 2012 Andreas Rumpf
+#        (c) Copyright 2013 Andreas Rumpf
 #
 #    See the file "copying.txt", included in this
 #    distribution, for details about the copyright.
@@ -13,7 +13,7 @@
 # included from cgen.nim
 
 type
-  TTraversalClosure {.pure, final.} = object
+  TTraversalClosure = object
     p: BProc
     visitorFrmt: string
 
@@ -127,3 +127,20 @@ proc genTraverseProc(m: BModule, typ: PType, reason: TTypeInfoReason): PRope =
   m.s[cfsProcs].app(generatedProc)
 
 
+proc genTraverseProcForGlobal(m: BModule, s: PSym): PRope =
+  discard genTypeInfo(m, s.loc.t)
+  
+  var c: TTraversalClosure
+  var p = newProc(nil, m)
+  result = getGlobalTempName()
+  
+  c.visitorFrmt = "#nimGCvisit((void*)$1, 0);$n"
+  c.p = p
+  let header = ropef("N_NIMCALL(void, $1)()", result)
+  genTraverseProc(c, s.loc.r, s.loc.t)
+  
+  let generatedProc = ropef("$1 {$n$2$3$4}$n",
+        [header, p.s(cpsLocals), p.s(cpsInit), p.s(cpsStmts)])
+  
+  m.s[cfsProcHeaders].appf("$1;$n", header)
+  m.s[cfsProcs].app(generatedProc)

compiler/ccgtypes.nim

@@ -1,7 +1,7 @@
 #
 #
 #           The Nimrod Compiler
-#        (c) Copyright 2012 Andreas Rumpf
+#        (c) Copyright 2013 Andreas Rumpf
 #
 #    See the file "copying.txt", included in this
 #    distribution, for details about the copyright.
@@ -938,7 +938,7 @@ proc genTypeInfo(m: BModule, typ: PType): PRope =
       genTupleInfo(m, fakeClosureType(t.owner), result)
   of tySequence, tyRef:
     genTypeInfoAux(m, t, result)
-    if usesNativeGC():
+    if gSelectedGC >= gcMarkAndSweep:
       let markerProc = genTraverseProc(m, t, tiNew)
       appf(m.s[cfsTypeInit3], "$1.marker = $2;$n", [result, markerProc])
   of tyPtr, tyRange: genTypeInfoAux(m, t, result)

compiler/commands.nim

@@ -139,10 +139,11 @@ proc testCompileOptionArg*(switch, arg: string, info: TLineInfo): bool =
   case switch.normalize
   of "gc":
     case arg.normalize
-    of "boehm": result = gSelectedGC == gcBoehm
-    of "refc":  result = gSelectedGC == gcRefc
-    of "v2":    result = gSelectedGC == gcV2
-    of "none":  result = gSelectedGC == gcNone
+    of "boehm":        result = gSelectedGC == gcBoehm
+    of "refc":         result = gSelectedGC == gcRefc
+    of "v2":           result = gSelectedGC == gcV2
+    of "markandsweep": result = gSelectedGC == gcMarkAndSweep
+    of "none":         result = gSelectedGC == gcNone
     else: LocalError(info, errNoneBoehmRefcExpectedButXFound, arg)
   of "opt":
     case arg.normalize
@@ -276,6 +277,9 @@ proc processSwitch(switch, arg: string, pass: TCmdlinePass, info: TLineInfo) =
       gSelectedGC = gcRefc
     of "v2":
       gSelectedGC = gcV2
+    of "markandsweep":
+      gSelectedGC = gcMarkAndSweep
+      defineSymbol("gcmarkandsweep")
     of "none":
       gSelectedGC = gcNone
       defineSymbol("nogc")

compiler/options.nim

@@ -80,8 +80,8 @@ type                          # please make sure we have under 32 options
     cmdInteractive,           # start interactive session
     cmdRun                    # run the project via TCC backend
   TStringSeq* = seq[string]
-  TGCMode* = enum                   # the selected GC
-    gcNone, gcBoehm, gcRefc, gcV2   #
+  TGCMode* = enum             # the selected GC
+    gcNone, gcBoehm, gcMarkAndSweep, gcRefc, gcV2
 
 const
   ChecksOptions* = {optObjCheck, optFieldCheck, optRangeCheck, optNilCheck, 
@@ -269,7 +269,6 @@ proc binaryStrSearch*(x: openarray[string], y: string): int =
       return mid
   result = - 1
 
-# Can we keep this? I'm using it all the time
 template nimdbg*: expr = c.module.fileIdx == gProjectMainIdx
 template cnimdbg*: expr = p.module.module.fileIdx == gProjectMainIdx
 template pnimdbg*: expr = p.lex.fileIdx == gProjectMainIdx