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gcenv.ee.cpp
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gcenv.ee.cpp
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
/*
* GCENV.EE.CPP
*
* GCToEEInterface implementation
*
*
*/
#include "gcrefmap.h"
void GCToEEInterface::SuspendEE(SUSPEND_REASON reason)
{
WRAPPER_NO_CONTRACT;
static_assert_no_msg(SUSPEND_FOR_GC == (int)ThreadSuspend::SUSPEND_FOR_GC);
static_assert_no_msg(SUSPEND_FOR_GC_PREP == (int)ThreadSuspend::SUSPEND_FOR_GC_PREP);
_ASSERTE(reason == SUSPEND_FOR_GC || reason == SUSPEND_FOR_GC_PREP);
g_pDebugInterface->SuspendForGarbageCollectionStarted();
ThreadSuspend::SuspendEE((ThreadSuspend::SUSPEND_REASON)reason);
g_pDebugInterface->SuspendForGarbageCollectionCompleted();
}
void GCToEEInterface::RestartEE(bool bFinishedGC)
{
WRAPPER_NO_CONTRACT;
g_pDebugInterface->ResumeForGarbageCollectionStarted();
ThreadSuspend::RestartEE(bFinishedGC, TRUE);
}
VOID GCToEEInterface::SyncBlockCacheWeakPtrScan(HANDLESCANPROC scanProc, uintptr_t lp1, uintptr_t lp2)
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
}
CONTRACTL_END;
SyncBlockCache::GetSyncBlockCache()->GCWeakPtrScan(scanProc, lp1, lp2);
}
void GCToEEInterface::BeforeGcScanRoots(int condemned, bool is_bgc, bool is_concurrent)
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
}
CONTRACTL_END;
#ifdef VERIFY_HEAP
if (is_bgc)
{
// Validate byrefs pinned by IL stubs since the last GC.
StubHelpers::ProcessByrefValidationList();
}
#endif // VERIFY_HEAP
Interop::OnBeforeGCScanRoots(is_concurrent);
}
//EE can perform post stack scanning action, while the
// user threads are still suspended
VOID GCToEEInterface::AfterGcScanRoots (int condemned, int max_gen,
ScanContext* sc)
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
}
CONTRACTL_END;
#ifdef FEATURE_COMINTEROP
// Go through all the only app domain and detach all the *unmarked* RCWs to prevent
// the RCW cache from resurrecting them.
::GetAppDomain()->DetachRCWs();
#endif // FEATURE_COMINTEROP
Interop::OnAfterGCScanRoots(sc->concurrent);
}
/*
* Scan all stack roots
*/
static void ScanStackRoots(Thread * pThread, promote_func* fn, ScanContext* sc)
{
GCCONTEXT gcctx;
gcctx.f = fn;
gcctx.sc = sc;
gcctx.cf = NULL;
ENABLE_FORBID_GC_LOADER_USE_IN_THIS_SCOPE();
// Either we are in a concurrent situation (in which case the thread is unknown to
// us), or we are performing a synchronous GC and we are the GC thread, holding
// the threadstore lock.
_ASSERTE(dbgOnly_IsSpecialEEThread() ||
GetThreadNULLOk() == NULL ||
// this is for background GC threads which always call this when EE is suspended.
IsGCSpecialThread() ||
(GetThread() == ThreadSuspend::GetSuspensionThread() && ThreadStore::HoldingThreadStore()));
Frame* pTopFrame = pThread->GetFrame();
Object ** topStack = (Object **)pTopFrame;
if ((pTopFrame != ((Frame*)-1))
&& (pTopFrame->GetVTablePtr() == InlinedCallFrame::GetMethodFrameVPtr())) {
// It is an InlinedCallFrame. Get SP from it.
InlinedCallFrame* pInlinedFrame = (InlinedCallFrame*)pTopFrame;
topStack = (Object **)pInlinedFrame->GetCallSiteSP();
}
sc->stack_limit = (uintptr_t)topStack;
#ifdef FEATURE_CONSERVATIVE_GC
if (g_pConfig->GetGCConservative())
{
// Conservative stack root reporting
// We will treat everything on stack as a pinned interior GC pointer
// Since we report every thing as pinned, we don't need to run following code for relocation phase.
if (sc->promotion)
{
Object ** bottomStack = (Object **) pThread->GetCachedStackBase();
Object ** walk;
for (walk = topStack; walk < bottomStack; walk ++)
{
if (((void*)*walk > (void*)bottomStack || (void*)*walk < (void*)topStack) &&
((void*)*walk >= (void*)g_lowest_address && (void*)*walk <= (void*)g_highest_address)
)
{
//DbgPrintf("promote " FMT_ADDR " : " FMT_ADDR "\n", walk, *walk);
fn(walk, sc, GC_CALL_INTERIOR|GC_CALL_PINNED);
}
}
}
// Also ask the explicit Frames to report any references they might know about.
// Generally these will be a subset of the objects reported below but there's
// nothing that guarantees that and in the specific case of a GC protect frame the
// references it protects may live at a lower address than the frame itself (and
// thus escape the stack range we scanned above).
Frame *pFrame = pThread->GetFrame();
while (pFrame != FRAME_TOP)
{
pFrame->GcScanRoots(fn, sc);
pFrame = pFrame->PtrNextFrame();
}
}
else
#endif
{
unsigned flagsStackWalk = ALLOW_ASYNC_STACK_WALK | ALLOW_INVALID_OBJECTS;
#if defined(FEATURE_EH_FUNCLETS)
flagsStackWalk |= GC_FUNCLET_REFERENCE_REPORTING;
#endif // defined(FEATURE_EH_FUNCLETS)
pThread->StackWalkFrames( GcStackCrawlCallBack, &gcctx, flagsStackWalk);
}
GCFrame* pGCFrame = pThread->GetGCFrame();
while (pGCFrame != NULL)
{
pGCFrame->GcScanRoots(fn, sc);
pGCFrame = pGCFrame->PtrNextFrame();
}
}
static void ScanTailCallArgBufferRoots(Thread* pThread, promote_func* fn, ScanContext* sc)
{
TailCallTls* tls = pThread->GetTailCallTls();
// Keep loader associated with CallTailCallTarget alive.
if (sc->promotion)
{
#ifndef DACCESS_COMPILE
const PortableTailCallFrame* frame = tls->GetFrame();
if (frame->NextCall != NULL)
{
MethodDesc* pMD = NonVirtualEntry2MethodDesc((PCODE)frame->NextCall);
if (pMD != NULL)
GcReportLoaderAllocator(fn, sc, pMD->GetLoaderAllocator());
}
#endif
}
TailCallArgBuffer* argBuffer = tls->GetArgBuffer();
if (argBuffer == NULL || argBuffer->GCDesc == NULL)
return;
if (argBuffer->State == TAILCALLARGBUFFER_ABANDONED)
return;
bool instArgOnly = argBuffer->State == TAILCALLARGBUFFER_INSTARG_ONLY;
GCRefMapDecoder decoder(static_cast<PTR_BYTE>(argBuffer->GCDesc));
while (!decoder.AtEnd())
{
int pos = decoder.CurrentPos();
int token = decoder.ReadToken();
PTR_TADDR ppObj = dac_cast<PTR_TADDR>(((BYTE*)argBuffer->Args) + pos * sizeof(TADDR));
switch (token)
{
case GCREFMAP_SKIP:
break;
case GCREFMAP_REF:
if (!instArgOnly)
fn(dac_cast<PTR_PTR_Object>(ppObj), sc, CHECK_APP_DOMAIN);
break;
case GCREFMAP_INTERIOR:
if (!instArgOnly)
PromoteCarefully(fn, dac_cast<PTR_PTR_Object>(ppObj), sc, GC_CALL_INTERIOR);
break;
case GCREFMAP_METHOD_PARAM:
if (sc->promotion)
{
#ifndef DACCESS_COMPILE
MethodDesc *pMDReal = dac_cast<PTR_MethodDesc>(*ppObj);
if (pMDReal != NULL)
GcReportLoaderAllocator(fn, sc, pMDReal->GetLoaderAllocator());
#endif
}
break;
case GCREFMAP_TYPE_PARAM:
if (sc->promotion)
{
#ifndef DACCESS_COMPILE
MethodTable *pMTReal = dac_cast<PTR_MethodTable>(*ppObj);
if (pMTReal != NULL)
GcReportLoaderAllocator(fn, sc, pMTReal->GetLoaderAllocator());
#endif
}
break;
default:
_ASSERTE(!"Unhandled GCREFMAP token in arg buffer GC desc");
break;
}
}
}
void GCToEEInterface::GcScanRoots(promote_func* fn, int condemned, int max_gen, ScanContext* sc)
{
STRESS_LOG1(LF_GCROOTS, LL_INFO10, "GCScan: Promotion Phase = %d\n", sc->promotion);
Thread* pThread = NULL;
while ((pThread = ThreadStore::GetThreadList(pThread)) != NULL)
{
STRESS_LOG2(LF_GC | LF_GCROOTS, LL_INFO100, "{ Starting scan of Thread %p ID = %x\n", pThread, pThread->GetThreadId());
if (GCHeapUtilities::GetGCHeap()->IsThreadUsingAllocationContextHeap(
pThread->GetAllocContext(), sc->thread_number))
{
sc->thread_under_crawl = pThread;
#ifdef FEATURE_EVENT_TRACE
sc->dwEtwRootKind = kEtwGCRootKindStack;
#endif // FEATURE_EVENT_TRACE
ScanStackRoots(pThread, fn, sc);
ScanTailCallArgBufferRoots(pThread, fn, sc);
#ifdef FEATURE_EVENT_TRACE
sc->dwEtwRootKind = kEtwGCRootKindOther;
#endif // FEATURE_EVENT_TRACE
}
STRESS_LOG2(LF_GC | LF_GCROOTS, LL_INFO100, "Ending scan of Thread %p ID = 0x%x }\n", pThread, pThread->GetThreadId());
}
// In server GC, we should be competing for marking the statics
// It's better to do this *after* stack scanning, because this way
// we can make up for imbalances in stack scanning
// This would not apply to the initial mark phase in background GC,
// but it would apply to blocking Gen 2 collections and the final
// marking stage in background GC where we catch up to the user program
if (GCHeapUtilities::MarkShouldCompeteForStatics())
{
if (condemned == max_gen && sc->promotion)
{
SystemDomain::EnumAllStaticGCRefs(fn, sc);
}
}
}
void GCToEEInterface::GcStartWork (int condemned, int max_gen)
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
}
CONTRACTL_END;
#ifdef VERIFY_HEAP
// Validate byrefs pinned by IL stubs since the last GC.
StubHelpers::ProcessByrefValidationList();
#endif // VERIFY_HEAP
ExecutionManager::CleanupCodeHeaps();
#ifdef FEATURE_EVENT_TRACE
ETW::TypeSystemLog::Cleanup();
#endif
Interop::OnGCStarted(condemned);
if (condemned == max_gen)
{
ThreadStore::s_pThreadStore->OnMaxGenerationGCStarted();
}
}
void GCToEEInterface::GcDone(int condemned)
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
}
CONTRACTL_END;
Interop::OnGCFinished(condemned);
}
bool GCToEEInterface::RefCountedHandleCallbacks(Object * pObject)
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
}
CONTRACTL_END;
#ifdef FEATURE_COMINTEROP
//<REVISIT_TODO>@todo optimize the access to the ref-count
ComCallWrapper* pWrap = ComCallWrapper::GetWrapperForObject((OBJECTREF)pObject);
if (pWrap != NULL && pWrap->IsWrapperActive())
return true;
#endif
#ifdef FEATURE_COMWRAPPERS
bool isRooted = false;
if (ComWrappersNative::HasManagedObjectComWrapper((OBJECTREF)pObject, &isRooted))
return isRooted;
#endif
#ifdef FEATURE_OBJCMARSHAL
bool isReferenced = false;
if (ObjCMarshalNative::IsTrackedReference((OBJECTREF)pObject, &isReferenced))
return isReferenced;
#endif
#if (defined(FEATURE_COMINTEROP) || defined(FEATURE_COMWRAPPERS)) && defined(FEATURE_OBJCMARSHAL)
#error COM and Objective-C are not supported at the same time.
#endif
return false;
}
void GCToEEInterface::SyncBlockCacheDemote(int max_gen)
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
}
CONTRACTL_END;
SyncBlockCache::GetSyncBlockCache()->GCDone(TRUE, max_gen);
}
void GCToEEInterface::SyncBlockCachePromotionsGranted(int max_gen)
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
}
CONTRACTL_END;
SyncBlockCache::GetSyncBlockCache()->GCDone(FALSE, max_gen);
}
uint32_t GCToEEInterface::GetActiveSyncBlockCount()
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
}
CONTRACTL_END;
return SyncBlockCache::GetSyncBlockCache()->GetActiveCount();
}
gc_alloc_context * GCToEEInterface::GetAllocContext()
{
WRAPPER_NO_CONTRACT;
Thread* pThread = ::GetThreadNULLOk();
if (!pThread)
{
return nullptr;
}
return pThread->GetAllocContext();
}
void GCToEEInterface::GcEnumAllocContexts(enum_alloc_context_func* fn, void* param)
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
}
CONTRACTL_END;
if (GCHeapUtilities::UseThreadAllocationContexts())
{
Thread * pThread = NULL;
while ((pThread = ThreadStore::GetThreadList(pThread)) != NULL)
{
fn(pThread->GetAllocContext(), param);
}
}
else
{
fn(&g_global_alloc_context, param);
}
}
uint8_t* GCToEEInterface::GetLoaderAllocatorObjectForGC(Object* pObject)
{
CONTRACTL
{
NOTHROW;
GC_NOTRIGGER;
}
CONTRACTL_END;
return pObject->GetGCSafeMethodTable()->GetLoaderAllocatorObjectForGC();
}
bool GCToEEInterface::IsPreemptiveGCDisabled()
{
WRAPPER_NO_CONTRACT;
Thread* pThread = ::GetThreadNULLOk();
return (pThread && pThread->PreemptiveGCDisabled());
}
bool GCToEEInterface::EnablePreemptiveGC()
{
WRAPPER_NO_CONTRACT;
Thread* pThread = ::GetThreadNULLOk();
if (pThread && pThread->PreemptiveGCDisabled())
{
pThread->EnablePreemptiveGC();
return true;
}
return false;
}
void GCToEEInterface::DisablePreemptiveGC()
{
WRAPPER_NO_CONTRACT;
Thread* pThread = ::GetThreadNULLOk();
if (pThread)
{
pThread->DisablePreemptiveGC();
}
}
Thread* GCToEEInterface::GetThread()
{
WRAPPER_NO_CONTRACT;
return ::GetThreadNULLOk();
}
//
// Diagnostics code
//
#if defined(GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
// Tracks all surviving objects (moved or otherwise).
inline bool ShouldTrackSurvivorsForProfilerOrEtw()
{
#ifdef GC_PROFILING
if (CORProfilerTrackGC())
return true;
#endif
#ifdef FEATURE_EVENT_TRACE
if (ETW::GCLog::ShouldTrackMovementForEtw())
return true;
#endif
return false;
}
// Only tracks surviving objects in compacting GCs (moved or otherwise).
inline bool ShouldTrackSurvivorsInCompactingGCsForProfiler()
{
#ifdef GC_PROFILING
if (CORProfilerTrackGCMovedObjects())
return true;
#endif
return false;
}
#endif // defined(GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
void ProfScanRootsHelper(Object** ppObject, ScanContext *pSC, uint32_t dwFlags)
{
#if defined(GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
Object *pObj = *ppObject;
if (dwFlags & GC_CALL_INTERIOR)
{
pObj = GCHeapUtilities::GetGCHeap()->GetContainingObject(pObj, true);
if (pObj == nullptr)
return;
}
ScanRootsHelper(pObj, ppObject, pSC, dwFlags);
#endif // defined(GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
}
// TODO - at some point we would like to completely decouple profiling
// from ETW tracing using a pattern similar to this, where the
// ProfilingScanContext has flags about whether or not certain things
// should be tracked, and each one of these ProfilerShouldXYZ functions
// will check these flags and determine what to do based upon that.
// GCProfileWalkHeapWorker can, in turn, call those methods without fear
// of things being ifdef'd out.
// Returns TRUE if GC profiling is enabled and the profiler
// should scan dependent handles, FALSE otherwise.
BOOL ProfilerShouldTrackConditionalWeakTableElements()
{
#if defined(GC_PROFILING)
return CORProfilerTrackConditionalWeakTableElements();
#else
return FALSE;
#endif // defined (GC_PROFILING)
}
// If GC profiling is enabled, informs the profiler that we are done
// tracing dependent handles.
void ProfilerEndConditionalWeakTableElementReferences(void* heapId)
{
#if defined (GC_PROFILING)
g_profControlBlock.pProfInterface->EndConditionalWeakTableElementReferences(heapId);
#else
UNREFERENCED_PARAMETER(heapId);
#endif // defined (GC_PROFILING)
}
// If GC profiling is enabled, informs the profiler that we are done
// tracing root references.
void ProfilerEndRootReferences2(void* heapId)
{
#if defined (GC_PROFILING)
g_profControlBlock.pProfInterface->EndRootReferences2(heapId);
#else
UNREFERENCED_PARAMETER(heapId);
#endif // defined (GC_PROFILING)
}
void GcScanRootsForProfilerAndETW(promote_func* fn, int condemned, int max_gen, ScanContext* sc)
{
Thread* pThread = NULL;
while ((pThread = ThreadStore::GetThreadList(pThread)) != NULL)
{
sc->thread_under_crawl = pThread;
#ifdef FEATURE_EVENT_TRACE
sc->dwEtwRootKind = kEtwGCRootKindStack;
#endif // FEATURE_EVENT_TRACE
ScanStackRoots(pThread, fn, sc);
ScanTailCallArgBufferRoots(pThread, fn, sc);
#ifdef FEATURE_EVENT_TRACE
sc->dwEtwRootKind = kEtwGCRootKindOther;
#endif // FEATURE_EVENT_TRACE
}
}
void ScanHandleForProfilerAndETW(Object** pRef, Object* pSec, uint32_t flags, ScanContext* context, bool isDependent)
{
ProfilingScanContext* pSC = (ProfilingScanContext*)context;
#ifdef GC_PROFILING
// Give the profiler the objectref.
if (pSC->fProfilerPinned)
{
if (!isDependent)
{
BEGIN_PIN_PROFILER(CORProfilerTrackGC());
g_profControlBlock.pProfInterface->RootReference2(
(uint8_t *)*pRef,
kEtwGCRootKindHandle,
(EtwGCRootFlags)flags,
pRef,
&pSC->pHeapId);
END_PIN_PROFILER();
}
else
{
BEGIN_PIN_PROFILER(CORProfilerTrackConditionalWeakTableElements());
g_profControlBlock.pProfInterface->ConditionalWeakTableElementReference(
(uint8_t*)*pRef,
(uint8_t*)pSec,
pRef,
&pSC->pHeapId);
END_PIN_PROFILER();
}
}
#endif // GC_PROFILING
#if defined(FEATURE_EVENT_TRACE)
// Notify ETW of the handle
if (ETW::GCLog::ShouldWalkHeapRootsForEtw())
{
ETW::GCLog::RootReference(
pRef,
*pRef, // object being rooted
pSec, // pSecondaryNodeForDependentHandle
isDependent,
pSC,
0, // dwGCFlags,
flags); // ETW handle flags
}
#endif // defined(FEATURE_EVENT_TRACE)
}
// This is called only if we've determined that either:
// a) The Profiling API wants to do a walk of the heap, and it has pinned the
// profiler in place (so it cannot be detached), and it's thus safe to call into the
// profiler, OR
// b) ETW infrastructure wants to do a walk of the heap either to log roots,
// objects, or both.
// This can also be called to do a single walk for BOTH a) and b) simultaneously. Since
// ETW can ask for roots, but not objects
#if defined(GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
void GCProfileWalkHeapWorker(BOOL fProfilerPinned, BOOL fShouldWalkHeapRootsForEtw, BOOL fShouldWalkHeapObjectsForEtw)
{
{
ProfilingScanContext SC(fProfilerPinned);
unsigned max_generation = GCHeapUtilities::GetGCHeap()->GetMaxGeneration();
// **** Scan roots: Only scan roots if profiling API wants them or ETW wants them.
if (fProfilerPinned || fShouldWalkHeapRootsForEtw)
{
GcScanRootsForProfilerAndETW(&ProfScanRootsHelper, max_generation, max_generation, &SC);
SC.dwEtwRootKind = kEtwGCRootKindFinalizer;
GCHeapUtilities::GetGCHeap()->DiagScanFinalizeQueue(&ProfScanRootsHelper, &SC);
// Handles are kept independent of wks/svr/concurrent builds
SC.dwEtwRootKind = kEtwGCRootKindHandle;
GCHeapUtilities::GetGCHeap()->DiagScanHandles(&ScanHandleForProfilerAndETW, max_generation, &SC);
// indicate that regular handle scanning is over, so we can flush the buffered roots
// to the profiler. (This is for profapi only. ETW will flush after the
// entire heap was is complete, via ETW::GCLog::EndHeapDump.)
if (fProfilerPinned)
{
ProfilerEndRootReferences2(&SC.pHeapId);
}
}
// **** Scan dependent handles: only if the profiler supports it or ETW wants roots
if ((fProfilerPinned && ProfilerShouldTrackConditionalWeakTableElements()) ||
fShouldWalkHeapRootsForEtw)
{
// GcScanDependentHandlesForProfiler double-checks
// CORProfilerTrackConditionalWeakTableElements() before calling into the profiler
ProfilingScanContext* pSC = &SC;
// we'll re-use pHeapId (which was either unused (0) or freed by EndRootReferences2
// (-1)), so reset it to NULL
_ASSERTE((*((size_t *)(&pSC->pHeapId)) == (size_t)(-1)) ||
(*((size_t *)(&pSC->pHeapId)) == (size_t)(0)));
pSC->pHeapId = NULL;
GCHeapUtilities::GetGCHeap()->DiagScanDependentHandles(&ScanHandleForProfilerAndETW, max_generation, &SC);
// indicate that dependent handle scanning is over, so we can flush the buffered roots
// to the profiler. (This is for profapi only. ETW will flush after the
// entire heap was is complete, via ETW::GCLog::EndHeapDump.)
if (fProfilerPinned && ProfilerShouldTrackConditionalWeakTableElements())
{
ProfilerEndConditionalWeakTableElementReferences(&SC.pHeapId);
}
}
ProfilerWalkHeapContext profilerWalkHeapContext(fProfilerPinned, SC.pvEtwContext);
// **** Walk objects on heap: only if profiling API wants them or ETW wants them.
if (fProfilerPinned || fShouldWalkHeapObjectsForEtw)
{
GCHeapUtilities::GetGCHeap()->DiagWalkHeap(&HeapWalkHelper, &profilerWalkHeapContext, max_generation, true /* walk the large object heap */);
}
#ifdef FEATURE_EVENT_TRACE
// **** Done! Indicate to ETW helpers that the heap walk is done, so any buffers
// should be flushed into the ETW stream
if (fShouldWalkHeapObjectsForEtw || fShouldWalkHeapRootsForEtw)
{
ETW::GCLog::EndHeapDump(&profilerWalkHeapContext);
}
#endif // FEATURE_EVENT_TRACE
}
}
#endif // defined(GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
void GCProfileWalkHeap(bool etwOnly)
{
BOOL fWalkedHeapForProfiler = FALSE;
#ifdef FEATURE_EVENT_TRACE
if (ETW::GCLog::ShouldWalkStaticsAndCOMForEtw())
ETW::GCLog::WalkStaticsAndCOMForETW();
BOOL fShouldWalkHeapRootsForEtw = ETW::GCLog::ShouldWalkHeapRootsForEtw();
BOOL fShouldWalkHeapObjectsForEtw = ETW::GCLog::ShouldWalkHeapObjectsForEtw();
#else // !FEATURE_EVENT_TRACE
BOOL fShouldWalkHeapRootsForEtw = FALSE;
BOOL fShouldWalkHeapObjectsForEtw = FALSE;
#endif // FEATURE_EVENT_TRACE
#if defined (GC_PROFILING)
{
BEGIN_PIN_PROFILER(!etwOnly && CORProfilerTrackGC());
GCProfileWalkHeapWorker(TRUE /* fProfilerPinned */, fShouldWalkHeapRootsForEtw, fShouldWalkHeapObjectsForEtw);
fWalkedHeapForProfiler = TRUE;
END_PIN_PROFILER();
}
#endif // defined (GC_PROFILING)
#if defined (GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
// we need to walk the heap if one of GC_PROFILING or FEATURE_EVENT_TRACE
// is defined, since both of them make use of the walk heap worker.
if (!fWalkedHeapForProfiler &&
(fShouldWalkHeapRootsForEtw || fShouldWalkHeapObjectsForEtw))
{
GCProfileWalkHeapWorker(FALSE /* fProfilerPinned */, fShouldWalkHeapRootsForEtw, fShouldWalkHeapObjectsForEtw);
}
#endif // defined(GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
}
void WalkFReachableObjects(bool isCritical, void* objectID)
{
g_profControlBlock.pProfInterface->FinalizeableObjectQueued(isCritical, (ObjectID)objectID);
}
static fq_walk_fn g_FQWalkFn = &WalkFReachableObjects;
void GCToEEInterface::DiagGCStart(int gen, bool isInduced)
{
#ifdef GC_PROFILING
DiagUpdateGenerationBounds();
GarbageCollectionStartedCallback(gen, isInduced);
{
BEGIN_PIN_PROFILER(CORProfilerTrackGC());
size_t context = 0;
// When we're walking objects allocated by class, then we don't want to walk the large
// object heap because then it would count things that may have been around for a while.
GCHeapUtilities::GetGCHeap()->DiagWalkHeap(&AllocByClassHelper, (void *)&context, 0, false);
// Notify that we've reached the end of the Gen 0 scan
g_profControlBlock.pProfInterface->EndAllocByClass(&context);
END_PIN_PROFILER();
}
#endif // GC_PROFILING
}
void GCToEEInterface::DiagUpdateGenerationBounds()
{
#ifdef GC_PROFILING
if (CORProfilerTrackGC() || CORProfilerTrackBasicGC())
UpdateGenerationBounds();
#endif // GC_PROFILING
}
void GCToEEInterface::DiagGCEnd(size_t index, int gen, int reason, bool fConcurrent)
{
#ifdef GC_PROFILING
// We were only doing generation bounds and GC finish callback for non concurrent GCs so
// I am keeping that behavior to not break profilers. But if BasicGC monitoring is enabled
// we will do these for all GCs.
if (!fConcurrent)
{
GCProfileWalkHeap(false);
}
if (CORProfilerTrackBasicGC() || (!fConcurrent && CORProfilerTrackGC()))
{
DiagUpdateGenerationBounds();
GarbageCollectionFinishedCallback();
}
#endif // GC_PROFILING
}
void GCToEEInterface::DiagWalkFReachableObjects(void* gcContext)
{
#ifdef GC_PROFILING
if (CORProfilerTrackGC())
{
BEGIN_PIN_PROFILER(CORProfilerPresent());
GCHeapUtilities::GetGCHeap()->DiagWalkFinalizeQueue(gcContext, g_FQWalkFn);
END_PIN_PROFILER();
}
#endif //GC_PROFILING
}
// Note on last parameter: when calling this for bgc, only ETW
// should be sending these events so that existing profapi profilers
// don't get confused.
void WalkMovedReferences(uint8_t* begin, uint8_t* end,
ptrdiff_t reloc,
void* context,
bool fCompacting,
bool fBGC)
{
ETW::GCLog::MovedReference(begin, end,
(fCompacting ? reloc : 0),
(size_t)context,
fCompacting,
!fBGC);
}
void GCToEEInterface::DiagWalkSurvivors(void* gcContext, bool fCompacting)
{
#if defined(GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
if (ShouldTrackSurvivorsForProfilerOrEtw() ||
(fCompacting && ShouldTrackSurvivorsInCompactingGCsForProfiler()))
{
size_t context = 0;
ETW::GCLog::BeginMovedReferences(&context);
GCHeapUtilities::GetGCHeap()->DiagWalkSurvivorsWithType(gcContext, &WalkMovedReferences, (void*)context, walk_for_gc);
ETW::GCLog::EndMovedReferences(context);
}
#endif //GC_PROFILING || FEATURE_EVENT_TRACE
}
void GCToEEInterface::DiagWalkUOHSurvivors(void* gcContext, int gen)
{
#if defined(GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
if (ShouldTrackSurvivorsForProfilerOrEtw())
{
size_t context = 0;
ETW::GCLog::BeginMovedReferences(&context);
GCHeapUtilities::GetGCHeap()->DiagWalkSurvivorsWithType(gcContext, &WalkMovedReferences, (void*)context, walk_for_uoh, gen);
ETW::GCLog::EndMovedReferences(context);
}
#endif //GC_PROFILING || FEATURE_EVENT_TRACE
}
void GCToEEInterface::DiagWalkBGCSurvivors(void* gcContext)
{
#if defined(GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
if (ShouldTrackSurvivorsForProfilerOrEtw())
{
size_t context = 0;
ETW::GCLog::BeginMovedReferences(&context);
GCHeapUtilities::GetGCHeap()->DiagWalkSurvivorsWithType(gcContext, &WalkMovedReferences, (void*)context, walk_for_bgc);
ETW::GCLog::EndMovedReferences(context);
}
#endif //GC_PROFILING || FEATURE_EVENT_TRACE
}
void GCToEEInterface::StompWriteBarrier(WriteBarrierParameters* args)
{
assert(args != nullptr);
int stompWBCompleteActions = SWB_PASS;
bool is_runtime_suspended = args->is_runtime_suspended;
switch (args->operation)
{
case WriteBarrierOp::StompResize:
// StompResize requires a new card table, a new lowest address, and
// a new highest address
assert(args->card_table != nullptr);
assert(args->lowest_address != nullptr);
assert(args->highest_address != nullptr);
// We are sensitive to the order of writes here (more comments on this further in the method)
// In particular g_card_table must be written before writing the heap bounds.
// For platforms with weak memory ordering we will issue fences, for x64/x86 we are ok
// as long as compiler does not reorder these writes.
// That is unlikely since we have method calls in between.
// Just to be robust agains possible refactoring/inlining we will do a compiler-fenced store here.
VolatileStoreWithoutBarrier(&g_card_table, args->card_table);
#ifdef FEATURE_MANUALLY_MANAGED_CARD_BUNDLES
assert(args->card_bundle_table != nullptr);
g_card_bundle_table = args->card_bundle_table;
#endif
#ifdef FEATURE_USE_SOFTWARE_WRITE_WATCH_FOR_GC_HEAP
if (g_sw_ww_enabled_for_gc_heap && (args->write_watch_table != nullptr))
{
assert(args->is_runtime_suspended);
g_sw_ww_table = args->write_watch_table;
}
#endif // FEATURE_USE_SOFTWARE_WRITE_WATCH_FOR_GC_HEAP
stompWBCompleteActions |= ::StompWriteBarrierResize(is_runtime_suspended, args->requires_upper_bounds_check);
is_runtime_suspended = (stompWBCompleteActions & SWB_EE_RESTART) || is_runtime_suspended;
if (stompWBCompleteActions & SWB_ICACHE_FLUSH)
{
// flushing/invalidating the write barrier's body for the current process
// NOTE: the underlying API may flush more than needed or nothing at all if Icache is coherent.
::FlushWriteBarrierInstructionCache();
}
// IMPORTANT: managed heap segments may surround unmanaged/stack segments. In such cases adding another managed
// heap segment may put a stack/unmanaged write inside the new heap range. However the old card table would
// not cover it. Therefore we must ensure that the write barriers see the new table before seeing the new bounds.
//
// On architectures with strong ordering, we only need to prevent compiler reordering.
// Otherwise we put a process-wide fence here (so that we could use an ordinary read in the barrier)
#if defined(HOST_ARM64) || defined(HOST_ARM)
if (!is_runtime_suspended)
{
// If runtime is not suspended, force all threads to see the changed table before seeing updated heap boundaries.
// See: http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/346765
FlushProcessWriteBuffers();
}
#endif
g_lowest_address = args->lowest_address;
g_highest_address = args->highest_address;
#if defined(HOST_ARM64) || defined(HOST_ARM)
// Need to reupdate for changes to g_highest_address g_lowest_address
stompWBCompleteActions |= ::StompWriteBarrierResize(is_runtime_suspended, args->requires_upper_bounds_check);
#ifdef HOST_ARM
if (stompWBCompleteActions & SWB_ICACHE_FLUSH)
{
// flushing/invalidating the write barrier's body for the current process
// NOTE: the underlying API may flush more than needed or nothing at all if Icache is coherent.
::FlushWriteBarrierInstructionCache();
}
#endif
#endif
// At this point either the old or the new set of globals (card_table, bounds etc) can be used. Card tables and card bundles allow such use.
// When card tables are de-published (at EE suspension) all the info will be merged, so the information will not be lost.
// Another point - we should not yet have any managed objects/addresses outside of the former bounds, so either old or new bounds are fine.
// That is - because bounds can only become wider and we are not yet done with widening.
//
// However!!
// Once we are done, a new object can (and likely will) be allocated outside of the former bounds.
// So, before such object can be used in a write barier, we must ensure that the barrier also uses the new bounds.
//
// This is easy to arrange for architectures with strong memory ordering. We only need to ensure that
// - object is allocated/published _after_ we publish bounds here
// - write barrier reads bounds after reading the new object locations
//
// for architectures with strong memory ordering (x86/x64) both conditions above are naturally guaranteed.
// Systems with weak ordering are more interesting. We could either:
// a) issue a write fence here and pair it with a read fence in the write barrier, or
// b) issue a process-wide full fence here and do ordinary reads in the barrier.
//
// We will do "b" because executing write barrier is by far more common than updating card table.
//
// I.E. - for weak architectures we have to do a process-wide fence.
//
// NOTE: suspending/resuming EE works the same as process-wide fence for our purposes here.
// (we care only about managed threads and suspend/resume will do full fences - good enough for us).
//
#if defined(HOST_ARM64) || defined(HOST_ARM)
is_runtime_suspended = (stompWBCompleteActions & SWB_EE_RESTART) || is_runtime_suspended;
if (!is_runtime_suspended)
{
// If runtime is not suspended, force all threads to see the changed state before observing future allocations.
FlushProcessWriteBuffers();
}
#endif
if (stompWBCompleteActions & SWB_EE_RESTART)
{
assert(!args->is_runtime_suspended &&
"if runtime was suspended in patching routines then it was in running state at beginning");