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singrdk/base/Kernel/Bartok/GCs/SemispaceCollector.cs

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RDK 1.1
2008-03-05 09:52:00 -05:00
/*******************************************************************/
/* WARNING */
/* This file should be identical in the Bartok and Singularity */
/* depots. Master copy resides in Bartok Depot. Changes should be */
/* made to Bartok Depot and propagated to Singularity Depot. */
/*******************************************************************/
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
namespace System.GCs {
using Microsoft.Bartok.Runtime;
using System.Collections;
using System.Runtime.CompilerServices;
using System.Threading;
#if SINGULARITY_KERNEL
using Microsoft.Singularity;
#endif
[NoCCtor]
internal unsafe class SemispaceCollector: GenerationalCollector
{
// WARNING: don't initialize any static fields in this class!
internal static CopyScan[] copyScanners;
internal static SemispaceCollector instance;
// Visitor instances used for marking objects
private static ForwardReferenceVisitor generalReferenceVisitor;
private static ForwardThreadReference threadReferenceVisitor;
private static RegisterPinnedReference pinnedReferenceVisitor;
private static ForwardOnlyReferenceVisitor forwardOnlyReferenceVisitor;
private SemispaceCollector() {
}
public static new void Initialize() {
GenerationalCollector.Initialize();
// copyScanners = new CopyScan[MAX_GENERATION+1];
copyScanners = (CopyScan[])
BootstrapMemory.Allocate(typeof(CopyScan[]),
(uint)MAX_GENERATION+1);
for (int i = (int)MIN_GENERATION; i <= (int)MAX_GENERATION; i++) {
switch (GC.copyscanType) {
case CopyScanType.CheneyScan: {
copyScanners[i] = (CopyScan)
BootstrapMemory.Allocate(typeof(CheneyScan));
break;
}
case CopyScanType.HierarchicalScan: {
copyScanners[i] = (CopyScan)
BootstrapMemory.Allocate(typeof(HierarchicalScan));
break;
}
case CopyScanType.NestedHierarchicalScan: {
copyScanners[i] = (CopyScan)
BootstrapMemory.Allocate(typeof(NestedHierarchicalScan));
break;
}
default: {
VTable.NotReached("Unknown CopyScan type: "+
GC.copyscanType);
break;
}
}
copyScanners[i].Initialize((PageType) i);
}
// SemispaceCollector.instance = new SemispaceCollector();
SemispaceCollector.instance = (SemispaceCollector)
BootstrapMemory.Allocate(typeof(SemispaceCollector));
// generalReferenceVisitor = new ForwardReferenceVisitor();
SemispaceCollector.generalReferenceVisitor = (ForwardReferenceVisitor)
BootstrapMemory.Allocate(typeof(ForwardReferenceVisitor));
// threadReferenceVisitor = new ForwardThreadReference(generalReferenceVisitor);
SemispaceCollector.threadReferenceVisitor = (ForwardThreadReference)
BootstrapMemory.Allocate(typeof(ForwardThreadReference));
// pinnedReferenceVisitor = new RegisterPinnedReference();
SemispaceCollector.pinnedReferenceVisitor = (RegisterPinnedReference)
BootstrapMemory.Allocate(typeof(RegisterPinnedReference));
// forwardOnlyReferenceVisitor = new ForwardOnlyReferenceVisitor();
SemispaceCollector.forwardOnlyReferenceVisitor = (ForwardOnlyReferenceVisitor)
BootstrapMemory.Allocate(typeof(ForwardOnlyReferenceVisitor));
}
internal override void TruncateOlderAllocationAreas(int generation) {
for (int i = (int)MIN_GENERATION; i <= generation; i++) {
copyScanners[i].TruncateAllocationArea();
}
}
internal override void CollectGeneration(int generation,
UIntPtr generationPageCount)
{
UIntPtr fromSpacePageCountTotal = UIntPtr.Zero;
for (int i = MinGeneration; i <= generation; i++) {
fromSpacePageCountTotal += fromSpacePageCounts[i];
}
PageType maxDestGeneration = (generation < (int)MAX_GENERATION)
? (PageType)(generation+1)
: MAX_GENERATION;
// The real work: find the roots, copy reachable objects
CollectorStatistics.Event(GCEvent.ComputeRootSet);
#if !VC
TryAllManager.PreGCHookTryAll();
#endif
bool onlyNew = false;
if (generation == (int)nurseryGeneration) {
onlyNew = true;
}
MultiUseWord.PreGCHook(false, /* don't use shadows */
onlyNew /* only scan new EMUs */);
Finalizer.PrepareCollectFinalizers();
CallStack.ScanStacks(null, pinnedReferenceVisitor);
pinnedReferenceVisitor.ProcessPinnedPages(generalReferenceVisitor);
CallStack.ScanStacks(threadReferenceVisitor, null);
Thread.VisitBootstrapData(generalReferenceVisitor);
#if SINGULARITY
Thread.UpdateAfterGC();
#endif
Thread currentThread = Thread.threadTable[collectorThreadIndex];
#if SINGULARITY_KERNEL
Kernel.VisitSpecialData(generalReferenceVisitor);
Kernel.UpdateAfterGC(currentThread);
#endif
MultiUseWord.VisitStrongRefs(generalReferenceVisitor,
false /* Don't use shadows */);
#if !VC
TryAllManager.VisitStrongRefs(generalReferenceVisitor);
#endif
StaticData.ScanStaticData(generalReferenceVisitor);
if ((PageType)generation < MAX_GENERATION) {
installedRemSet.Clean();
this.ScanRemSet((PageType) generation);
}
installedRemSet.Reset();
CollectorStatistics.Event(GCEvent.TraceStart);
this.ScanAndCopy(maxDestGeneration);
CollectorStatistics.Event(GCEvent.TraceSpecial);
WeakReference.Process(forwardOnlyReferenceVisitor, true, true);
Finalizer.ResurrectCandidates(forwardOnlyReferenceVisitor,
generalReferenceVisitor,
true);
this.ScanAndCopy(maxDestGeneration);
WeakReference.Process(forwardOnlyReferenceVisitor, true, false);
MultiUseWord.VisitWeakRefs(forwardOnlyReferenceVisitor,
false /* Don't use shadows */);
#if !VC
TryAllManager.VisitWeakRefs(forwardOnlyReferenceVisitor);
#endif
CollectorStatistics.Event(GCEvent.CollectionComplete);
// Clean up the auxiliary data structures
for (int i = MinGeneration + 1; i <= (int)maxDestGeneration; i++) {
copyScanners[i].Cleanup();
}
UnmanagedPageList.ReleaseStandbyPages();
pinnedReferenceVisitor.CleanPinnedPages();
MultiUseWord.PostGCHook(onlyNew);
Finalizer.ReleaseCollectFinalizers();
#if !VC
TryAllManager.PostGCHookTryAll();
#endif
}
internal override void EnableHeap() {
// Ensure that we don't call any type initializers during a GC
ArrayList pageList = new ArrayList();
pageList.Add(new UIntPtr(11));
pageList.Add(new UIntPtr(10));
UIntPtrComparer comparer = new UIntPtrComparer();
pageList.Sort(comparer);
}
// Internal workings of the collector
// Scan is large and will be inlined here. This is a performance
// workaround that performs manual specialization of the Scan method.
[NoInline]
private void ScanRemSet(PageType generation) {
installedRemSet.Scan(generalReferenceVisitor, generation);
}
private void ScanAndCopy(PageType maxDestGeneration) {
bool repeat = true;
while (repeat) {
repeat = false;
for (int gen = MinGeneration; gen <= (int)maxDestGeneration; gen++) {
if (copyScanners[gen].Scan(generalReferenceVisitor)) {
repeat = true;
}
}
}
}
// No objects can be resurrected using this mechanism
private class ForwardOnlyReferenceVisitor : NonNullReferenceVisitor
{
internal unsafe override void Visit(UIntPtr *loc) {
UIntPtr addr = *loc;
UIntPtr page = PageTable.Page(addr);
PageType pageType = PageTable.Type(page);
if (!PageTable.IsZombiePage(pageType)) {
VTable.Assert(PageTable.IsGcPage(pageType) ||
PageTable.IsNonGcPage(pageType) ||
PageTable.IsStackPage(pageType) ||
PageTable.IsSharedPage(pageType),
"Semispace:ForwardOnlyReferenceVisitor");
return;
}
PageType gen = PageTable.ZombieToLive(pageType);
UIntPtr vtableAddr = Allocator.GetObjectVTable(addr);
UIntPtr vtablePageIndex = PageTable.Page(vtableAddr);
if (PageTable.Type(vtablePageIndex) == gen) {
// The vtable field is really a forwarding pointer
*loc = vtableAddr;
} else {
// The object was not live
*loc = UIntPtr.Zero;
}
}
#region HELP_DEVIRT
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[ManualRefCounts]
internal override UIntPtr VisitReferenceFields(Object obj)
{
return this.VisitReferenceFields(Magic.addressOf(obj),
obj.vtable);
}
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[ManualRefCounts]
[InlineIntoOnce]
internal override
UIntPtr VisitReferenceFields(UIntPtr objectBase, VTable vtable)
{
ObjectDescriptor objDesc =
new ObjectDescriptor(vtable, objectBase);
return VisitReferenceFieldsTemplate(ref objDesc);
}
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[Inline]
protected override unsafe sealed
void Filter(UIntPtr *location, ref ObjectDescriptor objDesc)
{
base.Filter(location, ref objDesc);
}
#endregion
}
internal class ForwardReferenceVisitor : NonNullReferenceVisitor
{
internal unsafe override void Visit(UIntPtr *loc) {
UIntPtr objAddr = *loc;
UIntPtr page = PageTable.Page(objAddr);
Trace.Log(Trace.Area.Pointer,
"FwdRef: loc={0}, addr={1}, page={2}",
__arglist(loc, objAddr, page));
PageType pageType = PageTable.Type(page);
if (!PageTable.IsZombiePage(pageType)) {
VTable.Assert(PageTable.IsGcPage(pageType) ||
PageTable.IsNonGcPage(pageType) ||
PageTable.IsStackPage(pageType) ||
PageTable.IsSharedPage(pageType),
"Semispace:ForwardReferenceVisitor");
return;
}
PageType gen = PageTable.ZombieToLive(pageType);
VTable.Assert(gen > MIN_GENERATION);
Object obj = Magic.fromAddress(objAddr);
UIntPtr vtableAddr = *obj.VTableFieldAddr;
UIntPtr vtablePageIndex = PageTable.Page(vtableAddr);
if (PageTable.Type(vtablePageIndex) == gen) {
// The vtable field is really a forwarding pointer
Trace.Log(Trace.Area.Pointer,
"FwdRef: VT fwd: {0} -> {1}",
__arglist(objAddr, vtableAddr));
*loc = vtableAddr;
return;
}
Object newObject = copyScanners[(int)gen].Copy(obj);
*loc = Magic.addressOf(newObject);
}
#region HELP_DEVIRT
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[ManualRefCounts]
internal override UIntPtr VisitReferenceFields(Object obj)
{
return this.VisitReferenceFields(Magic.addressOf(obj),
obj.vtable);
}
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[ManualRefCounts]
[InlineIntoOnce]
internal override
UIntPtr VisitReferenceFields(UIntPtr objectBase, VTable vtable)
{
ObjectDescriptor objDesc =
new ObjectDescriptor(vtable, objectBase);
return VisitReferenceFieldsTemplate(ref objDesc);
}
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[Inline]
protected override unsafe sealed
void Filter(UIntPtr *location, ref ObjectDescriptor objDesc)
{
base.Filter(location, ref objDesc);
}
#endregion
}
private class ForwardThreadReference : NonNullReferenceVisitor
{
internal unsafe override void Visit(UIntPtr *loc) {
UIntPtr addr = *loc;
UIntPtr page = PageTable.Page(addr);
Trace.Log(Trace.Area.Pointer,
"FwdThrRef: loc={0}, addr={1}, page={2}",
__arglist(loc, addr, page));
PageType pageType = PageTable.Type(page);
// if an object "spills" into a page that
// is pinned, and the object is copied
// during a collection, we will end up with
// the first part of the object in a zombie page
// the second part of the object in a GC page.
// We need to find the start of the object and
// use that to determine whether the object has
// been moved.
if (!PageTable.IsZombiePage(pageType) &&
!PageTable.IsGcPage(pageType)) {
VTable.Assert(PageTable.IsNonGcPage(pageType) ||
PageTable.IsStackPage(pageType) ||
PageTable.IsSharedPage(pageType) ||
VTable.BuildC2Mods,
"Semispace:ForwardThreadReference");
return;
}
UIntPtr objectPtr = InteriorPtrTable.Find(addr);
if (objectPtr == addr) {
generalReferenceVisitor.Visit(loc);
} else {
// we can check for the page type of
// objectPtr here to see if it is zombie page.
// If true we can just return.
UIntPtr newObject = objectPtr;
generalReferenceVisitor.Visit(&newObject);
UIntPtr newAddr = newObject + (addr - objectPtr);
Trace.Log(Trace.Area.Pointer,
"FwdThrRef: {0} -> {1}",
__arglist(addr, newAddr));
*loc = newAddr;
}
}
#region HELP_DEVIRT
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[ManualRefCounts]
internal override UIntPtr VisitReferenceFields(Object obj)
{
return this.VisitReferenceFields(Magic.addressOf(obj),
obj.vtable);
}
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[ManualRefCounts]
[InlineIntoOnce]
internal override
UIntPtr VisitReferenceFields(UIntPtr objectBase, VTable vtable)
{
ObjectDescriptor objDesc =
new ObjectDescriptor(vtable, objectBase);
return VisitReferenceFieldsTemplate(ref objDesc);
}
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[Inline]
protected override unsafe sealed
void Filter(UIntPtr *location, ref ObjectDescriptor objDesc)
{
base.Filter(location, ref objDesc);
}
#endregion
internal ForwardReferenceVisitor ptrVisitor;
}
private class RegisterPinnedReference : NonNullReferenceVisitor
{
// BUGBUG: We are allocating an ArrayList while the collector
// is running. If the ArrayList gets big enough to be
// allocated in the older generation, then the RemSet has the
// potential to overflow since the boxed integers will reside
// in the young generation. We should eventually eliminate
// the use of ArrayList in this class as well as avoid boxing
// the page indices.
internal unsafe override void Visit(UIntPtr *loc) {
UIntPtr addr = *loc;
UIntPtr page = PageTable.Page(addr);
PageType pageType = PageTable.Type(page);
if (!PageTable.IsZombiePage(pageType)) {
VTable.Assert(PageTable.IsGcPage(pageType) ||
PageTable.IsNonGcPage(pageType) ||
PageTable.IsStackPage(pageType) ||
PageTable.IsSharedPage(pageType) ||
VTable.BuildC2Mods,
"Semispace:RegisterPinnedReference:1");
return;
}
PageType gen = PageTable.ZombieToLive(pageType);
UIntPtr pinnedObjectAddr = InteriorPtrTable.Find(addr);
if (pinnedPageList == null) {
pinnedPageList = new ArrayList();
comparer = new UIntPtrComparer();
}
Object pinnedObject = Magic.fromAddress(pinnedObjectAddr);
UIntPtr objectSize =
ObjectLayout.ObjectSize(pinnedObjectAddr,
pinnedObject.vtable);
UIntPtr beforeObjectAddr = pinnedObjectAddr - PreHeader.Size;
UIntPtr pastObjectAddr = beforeObjectAddr + objectSize;
UIntPtr firstPage = PageTable.Page(beforeObjectAddr);
UIntPtr lastPage = PageTable.Page(pastObjectAddr - 1);
for (UIntPtr i = firstPage; i <= lastPage; i++) {
if (!pinnedPageList.Contains(i)) {
Trace.Log(Trace.Area.Pointer,
"RegPin: ptr={0} page={1} gen={2}",
__arglist(pinnedObjectAddr, i, gen));
GenerationalCollector.gcPromotedTable[(int) gen-1] +=
PageTable.PageSize;
pinnedPageList.Add(i);
}
}
}
#region HELP_DEVIRT
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[ManualRefCounts]
internal override UIntPtr VisitReferenceFields(Object obj)
{
return this.VisitReferenceFields(Magic.addressOf(obj),
obj.vtable);
}
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[ManualRefCounts]
[InlineIntoOnce]
internal override
UIntPtr VisitReferenceFields(UIntPtr objectBase, VTable vtable)
{
ObjectDescriptor objDesc =
new ObjectDescriptor(vtable, objectBase);
return VisitReferenceFieldsTemplate(ref objDesc);
}
// This method simply forces the compiler to generate a copy
// of VisitReferenceFieldsTemplate in this class.
[Inline]
protected override unsafe sealed
void Filter(UIntPtr *location, ref ObjectDescriptor objDesc)
{
base.Filter(location, ref objDesc);
}
#endregion
internal void ProcessPinnedPages(ReferenceVisitor ptrVisitor) {
if (pinnedPageList == null || pinnedPageList.Count == 0) {
return;
}
pinnedPageList.Sort(comparer);
int limit = pinnedPageList.Count;
for (int i = 0; i < limit; i++) {
UIntPtr page = (UIntPtr) pinnedPageList[i];
PageType fromSpaceType = PageTable.Type(page);
VTable.Assert(PageTable.IsZombiePage(fromSpaceType),
"Semispace:RegisterPinnedReference:2");
PageType toSpaceType =
PageTable.ZombieToLive(fromSpaceType);
PageTable.SetType(page, toSpaceType);
}
int pageIndex = 0;
while (pageIndex < limit) {
UIntPtr startPage = (UIntPtr) pinnedPageList[pageIndex];
UIntPtr endPage = startPage + 1;
pageIndex++;
while (pageIndex < limit &&
(UIntPtr) pinnedPageList[pageIndex] == endPage) {
pageIndex++;
endPage++;
}
UIntPtr objectAddr = FirstPinnedObjectAddr(startPage);
UIntPtr pastAddr = PostPinnedObjectAddr(endPage);
while (objectAddr < pastAddr) {
if (Allocator.IsAlignment(objectAddr)) {
objectAddr += UIntPtr.Size;
} else if (BumpAllocator.IsUnusedSpace(objectAddr)) {
objectAddr = (PageTable.PagePad(objectAddr) +
PreHeader.Size);
} else {
Object obj = Magic.fromAddress(objectAddr);
objectAddr += ptrVisitor.VisitReferenceFields(obj);
}
}
}
}
internal void CleanPinnedPages() {
if (pinnedPageList == null || pinnedPageList.Count == 0) {
return;
}
int pageIndex = 0;
int limit = pinnedPageList.Count;
UIntPtr lastPostPinnedAddr = UIntPtr.Zero;
while (pageIndex < limit) {
UIntPtr startPage = (UIntPtr) pinnedPageList[pageIndex];
UIntPtr endPage = startPage + 1;
pageIndex++;
while (pageIndex < limit &&
(UIntPtr) pinnedPageList[pageIndex] == endPage) {
pageIndex++;
endPage++;
}
// Zero out the area between the start of the page and
// the first object on the page
UIntPtr firstObjectAddr = FirstPinnedObjectAddr(startPage);
UIntPtr firstAddr = firstObjectAddr - PreHeader.Size;
UIntPtr trashAddr = PageTable.PageAddr(startPage);
if (firstAddr < trashAddr) {
// The first object "spills" into the previous page,
// presumably by no more than HEADER_BYTES bytes
VTable.Assert(
PageTable.Page(firstAddr) == startPage - 1,
"Semispace:RegisterPinnedReference:3");
// Prepare to zero the preceding page unless it also
// had pinned data on it
trashAddr = PageTable.PageAddr(startPage - 1);
InteriorPtrTable.ClearFirst(startPage - 1);
if (trashAddr >= lastPostPinnedAddr) {
// Need to mark the spilled-onto page live to
// keep the spilled data around
PageType fromSpaceType =
PageTable.Type(startPage - 1);
VTable.Assert(
PageTable.IsZombiePage(fromSpaceType),
"Semispace:RegisterPinnedReference:4");
PageType toSpaceType =
PageTable.ZombieToLive(fromSpaceType);
PageTable.SetType(startPage - 1, toSpaceType);
}
}
// If lastPostPinnedAddr is on the page that trashAddr
// starts, pinned data from the last run of pinned pages
// and pinned data from this run of pinned data are on the
// same page, so just write alignment tokens from
// lastPostPinnedAddr to the first pinned object.
// Otherwise, write an unused marker at lastPostPinnedAddr
// since the rest of its page must be copied or dead.
if (trashAddr < lastPostPinnedAddr) {
trashAddr = lastPostPinnedAddr;
} else {
CleanPageTail(lastPostPinnedAddr);
}
if (GC.remsetType == RemSetType.Cards &&
trashAddr < firstAddr) {
UIntPtr firstCard = CardTable.CardNo(trashAddr);
UIntPtr lastCard = CardTable.CardNo(firstAddr -1);
if (!OffsetTable.NoObjectPtrToTheCard(firstCard)) {
UIntPtr offset= OffsetTable.GetOffset(firstCard);
UIntPtr objPtr =
CardTable.CardAddr(firstCard) + offset;
UIntPtr size = OffsetTable.ObjectSize(objPtr);
VTable.Assert
((objPtr + size - PreHeader.Size <= trashAddr)
|| (objPtr >= trashAddr),
"Object should be totally "
+ "above or below trashAddr");
if (objPtr >= trashAddr) {
// The offset in this card needs to be updated
OffsetTable.ClearCards(firstCard, firstCard);
}
}
OffsetTable.ClearCards(firstCard+1, lastCard-1);
if (lastCard != CardTable.CardNo(firstObjectAddr)) {
OffsetTable.ClearCards(lastCard, lastCard);
} else {
VTable.Assert(OffsetTable.GetOffset(lastCard)
>= (firstObjectAddr
- CardTable.CardAddr(lastCard)),
"wrong offset");
}
}
{
// trashAddr should go back at most one page.
UIntPtr trashPage = PageTable.Page(trashAddr);
UIntPtr firstObjectAddrPage =
PageTable.Page(firstObjectAddr);
VTable.Assert((trashPage == firstObjectAddrPage - 1)
|| (trashPage == firstObjectAddrPage));
}
// If the InteriorPtrTable already had a value, then this is
// redundant, but if the call to First above has to compute
// the value, then (since it won't store it in the table) we
// should store it. Why? At this point the previous page
// would be "connected" to this one. After this collection
// the previous page will be unused or re-used and unrelated
// to this page and subsequent calls to First would then
// rely on it making the leap between unrelated pages.
InteriorPtrTable.SetFirst(firstObjectAddr);
while (trashAddr < firstAddr) {
Allocator.WriteAlignment(trashAddr);
trashAddr += UIntPtr.Size;
}
// Zero out the area between the last whole object on
// the last page and the end of the last page
UIntPtr pastAddr = PostPinnedObjectAddr(endPage);
UIntPtr newEndPage =
PageTable.Page(PageTable.PagePad(pastAddr));
while (endPage < newEndPage) {
// The last object spills into the next page(s), so
// mark those page(s) live
PageType fromPageType = PageTable.Type(endPage);
if (PageTable.IsZombiePage(fromPageType)) {
PageType toSpaceType =
PageTable.ZombieToLive(fromPageType);
PageTable.SetType(endPage, toSpaceType);
} else {
// final page might be live already because
// something else on it was pinned.
// pageIndex has already been incremented,
// so it points to the start of the next
// set of contiguous pages
VTable.Assert(
PageTable.IsLiveGcPage(fromPageType) &&
pageIndex < limit &&
endPage ==
(UIntPtr) pinnedPageList[pageIndex],
"Semispace:RegisterPinnedReference:5");
}
++endPage;
}
lastPostPinnedAddr = pastAddr;
}
CleanPageTail(lastPostPinnedAddr);
pinnedPageList = null;
comparer = null;
}
private static void CleanPageTail(UIntPtr postPinnedAddr) {
if (!PageTable.PageAligned(postPinnedAddr)) {
// If postPinnedAddr points to the first object on its page,
// then we are removing all objects (specifically the part
// of the object that the InteriorPtrTable tracks, the
// vtables) from the page, so we should clear the page's
// entry in the InteriorPtrTable.
UIntPtr page = PageTable.Page(postPinnedAddr);
UIntPtr firstObjPtr = InteriorPtrTable.First(page);
if (firstObjPtr > postPinnedAddr) {
VTable.Assert
(firstObjPtr - PreHeader.Size >= postPinnedAddr,
"postPinnedAddr should not point to the "
+ "interior of an object (1)");
InteriorPtrTable.ClearFirst(page);
} else if (!BumpAllocator.IsUnusedSpace(firstObjPtr)) {
UIntPtr firstObjSize =
InteriorPtrTable.ObjectSize(firstObjPtr);
VTable.Assert
(firstObjPtr + firstObjSize - PreHeader.Size
<= postPinnedAddr,
"postPinnedAddr should not point to the "
+ "interior of an object (2)");
}
UIntPtr byteCount = PageTable.PagePad(postPinnedAddr)
- postPinnedAddr;
Util.MemClear(postPinnedAddr, byteCount);
BumpAllocator.WriteUnusedMarker(postPinnedAddr);
if (GC.remsetType == RemSetType.Cards && byteCount > 0) {
UIntPtr firstCard = CardTable.CardNo(postPinnedAddr);
UIntPtr lastCard =
CardTable.CardNo(postPinnedAddr + byteCount -1);
if (!OffsetTable.NoObjectPtrToTheCard(firstCard)) {
UIntPtr offset = OffsetTable.GetOffset(firstCard);
UIntPtr objPtr =
CardTable.CardAddr(firstCard) + offset;
UIntPtr size = OffsetTable.ObjectSize(objPtr);
VTable.Assert
((objPtr + size - PreHeader.Size
<= postPinnedAddr)
|| (objPtr >= postPinnedAddr),
"Object should be totally "
+ "above or below postPinnedAddr");
if (objPtr >= postPinnedAddr) {
OffsetTable.ClearCards(firstCard, firstCard);
}
}
OffsetTable.ClearCards(firstCard + 1, lastCard);
}
}
}
private static UIntPtr FirstPinnedObjectAddr(UIntPtr startPage) {
return InteriorPtrTable.First(startPage);
}
private static UIntPtr PostPinnedObjectAddr(UIntPtr endPage) {
UIntPtr endAddr = PageTable.PageAddr(endPage);
UIntPtr postLastObjectAddr = InteriorPtrTable.Last(endPage-1);
if (postLastObjectAddr < endAddr &&
!BumpAllocator.IsUnusedSpace(postLastObjectAddr)) {
// If the next object straddles into the next page,
// return the location just past the object
Object lastObject = Magic.fromAddress(postLastObjectAddr);
UIntPtr lastObjectSize =
ObjectLayout.ObjectSize(postLastObjectAddr,
lastObject.vtable);
postLastObjectAddr += lastObjectSize;
}
return postLastObjectAddr - PreHeader.Size;
}
internal ArrayList pinnedPageList;
internal UIntPtrComparer comparer; // type defined in UIntPtr.cs
}
}
// N.B. Must get two UIntPtrs!
internal class UIntPtrComparer : Collections.IComparer
{
public int Compare(Object x, Object y)
{
VTable.Assert(x is UIntPtr);
VTable.Assert(y is UIntPtr);
UIntPtr u = (UIntPtr) x;
UIntPtr v = (UIntPtr) y;
if(u < v) {
return -1;
}
if(u > v) {
return 1;
}
return 0;
}
}
}