Merge pull request #2 from nim-lang/devel

Update

1 files changed, 55 insertions, 82 deletions

diff --git a/lib/system/gc.nim b/lib/system/gc.nim
index dac06119d..425963f3f 100644
--- a/lib/system/gc.nim
+++ b/lib/system/gc.nim
@@ -21,10 +21,6 @@ const
                       # reaches this threshold
                       # this seems to be a good value
   withRealTime = defined(useRealtimeGC)
-  useMarkForDebug = defined(gcGenerational)
-  useBackupGc = true                      # use a simple M&S GC to collect
-                                          # cycles instead of the complex
-                                          # algorithm
 
 when withRealTime and not declared(getTicks):
   include "system/timers"
@@ -92,14 +88,12 @@ type
       maxPause: Nanos        # max allowed pause in nanoseconds; active if > 0
     region: MemRegion        # garbage collected region
     stat: GcStat
-    when useMarkForDebug or useBackupGc:
-      marked: CellSet
-      additionalRoots: CellSeq # dummy roots for GC_ref/unref
+    marked: CellSet
+    additionalRoots: CellSeq # dummy roots for GC_ref/unref
     when hasThreadSupport:
       toDispose: SharedList[pointer]
+    gcThreadId: int
 
-{.deprecated: [TWalkOp: WalkOp, TFinalizer: Finalizer, TGcHeap: GcHeap,
-              TGcStat: GcStat].}
 var
   gch {.rtlThreadVar.}: GcHeap
 
@@ -165,12 +159,12 @@ when defined(logGC):
         if not c.typ.name.isNil:
           typName = c.typ.name
 
-  when leakDetector:
-    c_fprintf(stdout, "[GC] %s: %p %d %s rc=%ld from %s(%ld)\n",
-              msg, c, kind, typName, c.refcount shr rcShift, c.filename, c.line)
-  else:
-    c_fprintf(stdout, "[GC] %s: %p %d %s rc=%ld; color=%ld\n",
-              msg, c, kind, typName, c.refcount shr rcShift, c.color)
+    when leakDetector:
+      c_fprintf(stdout, "[GC] %s: %p %d %s rc=%ld from %s(%ld)\n",
+                msg, c, kind, typName, c.refcount shr rcShift, c.filename, c.line)
+    else:
+      c_fprintf(stdout, "[GC] %s: %p %d %s rc=%ld; thread=%ld\n",
+                msg, c, kind, typName, c.refcount shr rcShift, gch.gcThreadId)
 
 template gcTrace(cell, state: untyped) =
   when traceGC: traceCell(cell, state)
@@ -314,27 +308,12 @@ proc initGC() =
     init(gch.zct)
     init(gch.tempStack)
     init(gch.decStack)
-    when useMarkForDebug or useBackupGc:
-      init(gch.marked)
-      init(gch.additionalRoots)
+    init(gch.marked)
+    init(gch.additionalRoots)
     when hasThreadSupport:
       init(gch.toDispose)
-
-when useMarkForDebug or useBackupGc:
-  type
-    GlobalMarkerProc = proc () {.nimcall, benign.}
-  {.deprecated: [TGlobalMarkerProc: GlobalMarkerProc].}
-  var
-    globalMarkersLen: int
-    globalMarkers: array[0.. 7_000, GlobalMarkerProc]
-
-  proc nimRegisterGlobalMarker(markerProc: GlobalMarkerProc) {.compilerProc.} =
-    if globalMarkersLen <= high(globalMarkers):
-      globalMarkers[globalMarkersLen] = markerProc
-      inc globalMarkersLen
-    else:
-      echo "[GC] cannot register global variable; too many global variables"
-      quit 1
+    gch.gcThreadId = atomicInc(gHeapidGenerator) - 1
+    gcAssert(gch.gcThreadId >= 0, "invalid computed thread ID")
 
 proc cellsetReset(s: var CellSet) =
   deinit(s)
@@ -377,10 +356,10 @@ proc forAllChildrenAux(dest: pointer, mt: PNimType, op: WalkOp) =
     else: discard
 
 proc forAllChildren(cell: PCell, op: WalkOp) =
-  gcAssert(cell != nil, "forAllChildren: 1")
-  gcAssert(isAllocatedPtr(gch.region, cell), "forAllChildren: 2")
-  gcAssert(cell.typ != nil, "forAllChildren: 3")
-  gcAssert cell.typ.kind in {tyRef, tyOptAsRef, tySequence, tyString}, "forAllChildren: 4"
+  gcAssert(cell != nil, "forAllChildren: cell is nil")
+  gcAssert(isAllocatedPtr(gch.region, cell), "forAllChildren: pointer not part of the heap")
+  gcAssert(cell.typ != nil, "forAllChildren: cell.typ is nil")
+  gcAssert cell.typ.kind in {tyRef, tyOptAsRef, tySequence, tyString}, "forAllChildren: unknown GC'ed type"
   let marker = cell.typ.marker
   if marker != nil:
     marker(cellToUsr(cell), op.int)
@@ -481,7 +460,7 @@ proc rawNewObj(typ: PNimType, size: int, gch: var GcHeap): pointer =
   release(gch)
   when useCellIds:
     inc gch.idGenerator
-    res.id = gch.idGenerator
+    res.id = gch.idGenerator * 1000_000 + gch.gcThreadId
   result = cellToUsr(res)
   sysAssert(allocInv(gch.region), "rawNewObj end")
 
@@ -528,7 +507,7 @@ proc newObjRC1(typ: PNimType, size: int): pointer {.compilerRtl.} =
   release(gch)
   when useCellIds:
     inc gch.idGenerator
-    res.id = gch.idGenerator
+    res.id = gch.idGenerator * 1000_000 + gch.gcThreadId
   result = cellToUsr(res)
   zeroMem(result, size)
   sysAssert(allocInv(gch.region), "newObjRC1 end")
@@ -556,7 +535,7 @@ proc growObj(old: pointer, newsize: int, gch: var GcHeap): pointer =
 
   var oldsize = cast[PGenericSeq](old).len*elemSize + GenericSeqSize
   copyMem(res, ol, oldsize + sizeof(Cell))
-  zeroMem(cast[pointer](cast[ByteAddress](res)+% oldsize +% sizeof(Cell)),
+  zeroMem(cast[pointer](cast[ByteAddress](res) +% oldsize +% sizeof(Cell)),
           newsize-oldsize)
   sysAssert((cast[ByteAddress](res) and (MemAlign-1)) == 0, "growObj: 3")
   # This can be wrong for intermediate temps that are nevertheless on the
@@ -598,7 +577,7 @@ proc growObj(old: pointer, newsize: int, gch: var GcHeap): pointer =
   release(gch)
   when useCellIds:
     inc gch.idGenerator
-    res.id = gch.idGenerator
+    res.id = gch.idGenerator * 1000_000 + gch.gcThreadId
   result = cellToUsr(res)
   sysAssert(allocInv(gch.region), "growObj end")
   when defined(memProfiler): nimProfile(newsize-oldsize)
@@ -623,29 +602,31 @@ proc freeCyclicCell(gch: var GcHeap, c: PCell) =
     gcAssert(c.typ != nil, "freeCyclicCell")
     zeroMem(c, sizeof(Cell))
 
-when useBackupGc:
-  proc sweep(gch: var GcHeap) =
-    for x in allObjects(gch.region):
-      if isCell(x):
-        # cast to PCell is correct here:
-        var c = cast[PCell](x)
-        if c notin gch.marked: freeCyclicCell(gch, c)
-
-when useMarkForDebug or useBackupGc:
-  proc markS(gch: var GcHeap, c: PCell) =
-    incl(gch.marked, c)
-    gcAssert gch.tempStack.len == 0, "stack not empty!"
-    forAllChildren(c, waMarkPrecise)
-    while gch.tempStack.len > 0:
-      dec gch.tempStack.len
-      var d = gch.tempStack.d[gch.tempStack.len]
-      if not containsOrIncl(gch.marked, d):
-        forAllChildren(d, waMarkPrecise)
-
-  proc markGlobals(gch: var GcHeap) =
+proc sweep(gch: var GcHeap) =
+  for x in allObjects(gch.region):
+    if isCell(x):
+      # cast to PCell is correct here:
+      var c = cast[PCell](x)
+      if c notin gch.marked: freeCyclicCell(gch, c)
+
+proc markS(gch: var GcHeap, c: PCell) =
+  gcAssert isAllocatedPtr(gch.region, c), "markS: foreign heap root detected A!"
+  incl(gch.marked, c)
+  gcAssert gch.tempStack.len == 0, "stack not empty!"
+  forAllChildren(c, waMarkPrecise)
+  while gch.tempStack.len > 0:
+    dec gch.tempStack.len
+    var d = gch.tempStack.d[gch.tempStack.len]
+    gcAssert isAllocatedPtr(gch.region, d), "markS: foreign heap root detected B!"
+    if not containsOrIncl(gch.marked, d):
+      forAllChildren(d, waMarkPrecise)
+
+proc markGlobals(gch: var GcHeap) =
+  if gch.gcThreadId == 0:
     for i in 0 .. globalMarkersLen-1: globalMarkers[i]()
-    let d = gch.additionalRoots.d
-    for i in 0 .. gch.additionalRoots.len-1: markS(gch, d[i])
+  for i in 0 .. threadLocalMarkersLen-1: threadLocalMarkers[i]()
+  let d = gch.additionalRoots.d
+  for i in 0 .. gch.additionalRoots.len-1: markS(gch, d[i])
 
 when logGC:
   var
@@ -689,16 +670,9 @@ proc doOperation(p: pointer, op: WalkOp) =
   of waPush:
     add(gch.tempStack, c)
   of waMarkGlobal:
-    when useMarkForDebug or useBackupGc:
-      when hasThreadSupport:
-        # could point to a cell which we don't own and don't want to touch/trace
-        if isAllocatedPtr(gch.region, c):
-          markS(gch, c)
-      else:
-        markS(gch, c)
+    markS(gch, c)
   of waMarkPrecise:
-    when useMarkForDebug or useBackupGc:
-      add(gch.tempStack, c)
+    add(gch.tempStack, c)
   #of waDebug: debugGraph(c)
 
 proc nimGCvisit(d: pointer, op: int) {.compilerRtl.} =
@@ -712,14 +686,13 @@ proc collectCycles(gch: var GcHeap) =
       nimGCunref(c)
   # ensure the ZCT 'color' is not used:
   while gch.zct.len > 0: discard collectZCT(gch)
-  when useBackupGc:
-    cellsetReset(gch.marked)
-    var d = gch.decStack.d
-    for i in 0..gch.decStack.len-1:
-      sysAssert isAllocatedPtr(gch.region, d[i]), "collectCycles"
-      markS(gch, d[i])
-    markGlobals(gch)
-    sweep(gch)
+  cellsetReset(gch.marked)
+  var d = gch.decStack.d
+  for i in 0..gch.decStack.len-1:
+    sysAssert isAllocatedPtr(gch.region, d[i]), "collectCycles"
+    markS(gch, d[i])
+  markGlobals(gch)
+  sweep(gch)
 
 proc gcMark(gch: var GcHeap, p: pointer) {.inline.} =
   # the addresses are not as cells on the stack, so turn them to cells:
@@ -860,7 +833,7 @@ proc collectCT(gch: var GcHeap) =
   if (gch.zct.len >= stackMarkCosts or (cycleGC and
       getOccupiedMem(gch.region)>=gch.cycleThreshold) or alwaysGC) and
       gch.recGcLock == 0:
-    when useMarkForDebug:
+    when false:
       prepareForInteriorPointerChecking(gch.region)
       cellsetReset(gch.marked)
       markForDebug(gch)