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-rw-r--r--js/src/jsgc.cpp203
1 files changed, 112 insertions, 91 deletions
diff --git a/js/src/jsgc.cpp b/js/src/jsgc.cpp
index 3d4dae9bb..5a9d732b6 100644
--- a/js/src/jsgc.cpp
+++ b/js/src/jsgc.cpp
@@ -207,7 +207,6 @@
#include "jsscript.h"
#include "jstypes.h"
#include "jsutil.h"
-#include "jswatchpoint.h"
#include "jsweakmap.h"
#ifdef XP_WIN
# include "jswin.h"
@@ -1524,19 +1523,11 @@ GCMarker::delayMarkingChildren(const void* thing)
}
inline void
-ArenaLists::prepareForIncrementalGC(JSRuntime* rt)
+ArenaLists::prepareForIncrementalGC()
{
+ purge();
for (auto i : AllAllocKinds()) {
- FreeSpan* span = freeLists[i];
- if (span != &placeholder) {
- if (!span->isEmpty()) {
- Arena* arena = span->getArena();
- arena->allocatedDuringIncremental = true;
- rt->gc.marker.delayMarkingArena(arena);
- } else {
- freeLists[i] = &placeholder;
- }
- }
+ arenaLists[i].moveCursorToEnd();
}
}
@@ -2251,7 +2242,7 @@ GCRuntime::updateTypeDescrObjects(MovingTracer* trc, Zone* zone)
{
zone->typeDescrObjects.sweep();
for (auto r = zone->typeDescrObjects.all(); !r.empty(); r.popFront())
- UpdateCellPointers(trc, r.front().get());
+ UpdateCellPointers(trc, r.front());
}
void
@@ -2310,22 +2301,27 @@ GCRuntime::updateCellPointers(MovingTracer* trc, Zone* zone, AllocKinds kinds, s
// 2) typed object type descriptor objects
// 3) all other objects
//
+// Also, there can be data races calling IsForwarded() on the new location of a
+// cell that is being updated in parallel on another thread. This can be avoided
+// by updating some kinds of cells in different phases. This is done for JSScripts
+// and LazyScripts, and JSScripts and Scopes.
+//
// Since we want to minimize the number of phases, we put everything else into
// the first phase and label it the 'misc' phase.
static const AllocKinds UpdatePhaseMisc {
AllocKind::SCRIPT,
- AllocKind::LAZY_SCRIPT,
AllocKind::BASE_SHAPE,
AllocKind::SHAPE,
AllocKind::ACCESSOR_SHAPE,
AllocKind::OBJECT_GROUP,
AllocKind::STRING,
- AllocKind::JITCODE,
- AllocKind::SCOPE
+ AllocKind::JITCODE
};
static const AllocKinds UpdatePhaseObjects {
+ AllocKind::LAZY_SCRIPT,
+ AllocKind::SCOPE,
AllocKind::FUNCTION,
AllocKind::FUNCTION_EXTENDED,
AllocKind::OBJECT0,
@@ -2395,11 +2391,6 @@ GCRuntime::updatePointersToRelocatedCells(Zone* zone, AutoLockForExclusiveAccess
Debugger::markIncomingCrossCompartmentEdges(&trc);
WeakMapBase::markAll(zone, &trc);
- for (CompartmentsInZoneIter c(zone); !c.done(); c.next()) {
- c->trace(&trc);
- if (c->watchpointMap)
- c->watchpointMap->markAll(&trc);
- }
// Mark all gray roots, making sure we call the trace callback to get the
// current set.
@@ -2408,7 +2399,6 @@ GCRuntime::updatePointersToRelocatedCells(Zone* zone, AutoLockForExclusiveAccess
}
// Sweep everything to fix up weak pointers
- WatchpointMap::sweepAll(rt);
Debugger::sweepAll(rt->defaultFreeOp());
jit::JitRuntime::SweepJitcodeGlobalTable(rt);
rt->gc.sweepZoneAfterCompacting(zone);
@@ -3574,6 +3564,23 @@ RelazifyFunctions(Zone* zone, AllocKind kind)
}
}
+static bool
+ShouldCollectZone(Zone* zone, JS::gcreason::Reason reason)
+{
+ // Normally we collect all scheduled zones.
+ if (reason != JS::gcreason::COMPARTMENT_REVIVED)
+ return zone->isGCScheduled();
+
+ // If we are repeating a GC because we noticed dead compartments haven't
+ // been collected, then only collect zones containing those compartments.
+ for (CompartmentsInZoneIter comp(zone); !comp.done(); comp.next()) {
+ if (comp->scheduledForDestruction)
+ return true;
+ }
+
+ return false;
+}
+
bool
GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAccess& lock)
{
@@ -3597,7 +3604,7 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAcces
#endif
/* Set up which zones will be collected. */
- if (zone->isGCScheduled()) {
+ if (ShouldCollectZone(zone, reason)) {
if (!zone->isAtomsZone()) {
any = true;
zone->setGCState(Zone::Mark);
@@ -3616,7 +3623,7 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAcces
for (CompartmentsIter c(rt, WithAtoms); !c.done(); c.next()) {
c->marked = false;
c->scheduledForDestruction = false;
- c->maybeAlive = false;
+ c->maybeAlive = c->hasBeenEntered() || !c->zone()->isGCScheduled();
if (shouldPreserveJITCode(c, currentTime, reason, canAllocateMoreCode))
c->zone()->setPreservingCode(true);
}
@@ -3636,6 +3643,7 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAcces
* on. If the value of keepAtoms() changes between GC slices, then we'll
* cancel the incremental GC. See IsIncrementalGCSafe.
*/
+
if (isFull && !rt->keepAtoms()) {
Zone* atomsZone = rt->atomsCompartment(lock)->zone();
if (atomsZone->isGCScheduled()) {
@@ -3650,15 +3658,12 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAcces
return false;
/*
- * At the end of each incremental slice, we call prepareForIncrementalGC,
- * which marks objects in all arenas that we're currently allocating
- * into. This can cause leaks if unreachable objects are in these
- * arenas. This purge call ensures that we only mark arenas that have had
- * allocations after the incremental GC started.
+ * Ensure that after the start of a collection we don't allocate into any
+ * existing arenas, as this can cause unreachable things to be marked.
*/
if (isIncremental) {
for (GCZonesIter zone(rt); !zone.done(); zone.next())
- zone->arenas.purge();
+ zone->arenas.prepareForIncrementalGC();
}
MemProfiler::MarkTenuredStart(rt);
@@ -3743,12 +3748,10 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAcces
gcstats::AutoPhase ap2(stats, gcstats::PHASE_MARK_ROOTS);
if (isIncremental) {
- gcstats::AutoPhase ap3(stats, gcstats::PHASE_BUFFER_GRAY_ROOTS);
bufferGrayRoots();
+ markCompartments();
}
-
- markCompartments();
-
+
return true;
}
@@ -3761,9 +3764,14 @@ GCRuntime::markCompartments()
* This code ensures that if a compartment is "dead", then it will be
* collected in this GC. A compartment is considered dead if its maybeAlive
* flag is false. The maybeAlive flag is set if:
- * (1) the compartment has incoming cross-compartment edges, or
- * (2) an object in the compartment was marked during root marking, either
- * as a black root or a gray root.
+ * (1) the compartment has been entered (set in beginMarkPhase() above)
+ * (2) the compartment is not being collected (set in beginMarkPhase()
+ * above)
+ * (3) an object in the compartment was marked during root marking, either
+ * as a black root or a gray root (set in RootMarking.cpp), or
+ * (4) the compartment has incoming cross-compartment edges from another
+ * compartment that has maybeAlive set (set by this method).
+ *
* If the maybeAlive is false, then we set the scheduledForDestruction flag.
* At the end of the GC, we look for compartments where
* scheduledForDestruction is true. These are compartments that were somehow
@@ -3781,26 +3789,37 @@ GCRuntime::markCompartments()
* allocation and read barriers during JS_TransplantObject and the like.
*/
- /* Set the maybeAlive flag based on cross-compartment edges. */
- for (CompartmentsIter c(rt, SkipAtoms); !c.done(); c.next()) {
- for (JSCompartment::WrapperEnum e(c); !e.empty(); e.popFront()) {
+ /* Propagate the maybeAlive flag via cross-compartment edges. */
+
+ Vector<JSCompartment*, 0, js::SystemAllocPolicy> workList;
+
+ for (CompartmentsIter comp(rt, SkipAtoms); !comp.done(); comp.next()) {
+ if (comp->maybeAlive) {
+ if (!workList.append(comp))
+ return;
+ }
+ }
+ while (!workList.empty()) {
+ JSCompartment* comp = workList.popCopy();
+ for (JSCompartment::WrapperEnum e(comp); !e.empty(); e.popFront()) {
if (e.front().key().is<JSString*>())
continue;
JSCompartment* dest = e.front().mutableKey().compartment();
- if (dest)
+ if (dest && !dest->maybeAlive) {
dest->maybeAlive = true;
+ if (!workList.append(dest))
+ return;
+ }
}
}
- /*
- * For black roots, code in gc/Marking.cpp will already have set maybeAlive
- * during MarkRuntime.
- */
-
- /* Propogate maybeAlive to scheduleForDestruction. */
- for (GCCompartmentsIter c(rt); !c.done(); c.next()) {
- if (!c->maybeAlive && !rt->isAtomsCompartment(c))
- c->scheduledForDestruction = true;
+
+ /* Set scheduleForDestruction based on maybeAlive. */
+
+ for (GCCompartmentsIter comp(rt); !comp.done(); comp.next()) {
+ MOZ_ASSERT(!comp->scheduledForDestruction);
+ if (!comp->maybeAlive && !rt->isAtomsCompartment(comp))
+ comp->scheduledForDestruction = true;
}
}
@@ -3824,10 +3843,6 @@ GCRuntime::markWeakReferences(gcstats::Phase phase)
for (ZoneIterT zone(rt); !zone.done(); zone.next())
markedAny |= WeakMapBase::markZoneIteratively(zone, &marker);
}
- for (CompartmentsIterT<ZoneIterT> c(rt); !c.done(); c.next()) {
- if (c->watchpointMap)
- markedAny |= c->watchpointMap->markIteratively(&marker);
- }
markedAny |= Debugger::markAllIteratively(&marker);
markedAny |= jit::JitRuntime::MarkJitcodeGlobalTableIteratively(&marker);
@@ -4599,9 +4614,6 @@ GCRuntime::beginSweepingZoneGroup(AutoLockForExclusiveAccess& lock)
// Bug 1071218: the following two methods have not yet been
// refactored to work on a single zone-group at once.
- // Collect watch points associated with unreachable objects.
- WatchpointMap::sweepAll(rt);
-
// Detach unreachable debuggers and global objects from each other.
Debugger::sweepAll(&fop);
@@ -5301,7 +5313,7 @@ AutoGCSlice::~AutoGCSlice()
for (ZonesIter zone(runtime, WithAtoms); !zone.done(); zone.next()) {
if (zone->isGCMarking()) {
zone->setNeedsIncrementalBarrier(true, Zone::UpdateJit);
- zone->arenas.prepareForIncrementalGC(runtime);
+ zone->arenas.purge();
} else {
zone->setNeedsIncrementalBarrier(false, Zone::UpdateJit);
}
@@ -5482,7 +5494,7 @@ gc::AbortReason
gc::IsIncrementalGCUnsafe(JSRuntime* rt)
{
MOZ_ASSERT(!rt->mainThread.suppressGC);
-
+
if (rt->keepAtoms())
return gc::AbortReason::KeepAtomsSet;
@@ -5493,9 +5505,17 @@ gc::IsIncrementalGCUnsafe(JSRuntime* rt)
}
void
-GCRuntime::budgetIncrementalGC(SliceBudget& budget, AutoLockForExclusiveAccess& lock)
+GCRuntime::budgetIncrementalGC(JS::gcreason::Reason reason, SliceBudget& budget,
+ AutoLockForExclusiveAccess& lock)
{
AbortReason unsafeReason = IsIncrementalGCUnsafe(rt);
+ if (unsafeReason == AbortReason::None) {
+ if (reason == JS::gcreason::COMPARTMENT_REVIVED)
+ unsafeReason = gc::AbortReason::CompartmentRevived;
+ else if (mode != JSGC_MODE_INCREMENTAL)
+ unsafeReason = gc::AbortReason::ModeChange;
+ }
+
if (unsafeReason != AbortReason::None) {
resetIncrementalGC(unsafeReason, lock);
budget.makeUnlimited();
@@ -5503,12 +5523,7 @@ GCRuntime::budgetIncrementalGC(SliceBudget& budget, AutoLockForExclusiveAccess&
return;
}
- if (mode != JSGC_MODE_INCREMENTAL) {
- resetIncrementalGC(AbortReason::ModeChange, lock);
- budget.makeUnlimited();
- stats.nonincremental(AbortReason::ModeChange);
- return;
- }
+
if (isTooMuchMalloc()) {
budget.makeUnlimited();
@@ -5667,7 +5682,7 @@ GCRuntime::gcCycle(bool nonincrementalByAPI, SliceBudget& budget, JS::gcreason::
stats.nonincremental(gc::AbortReason::NonIncrementalRequested);
budget.makeUnlimited();
} else {
- budgetIncrementalGC(budget, session.lock);
+ budgetIncrementalGC(reason, budget, session.lock);
}
/* The GC was reset, so we need a do-over. */
@@ -5759,6 +5774,22 @@ GCRuntime::checkIfGCAllowedInCurrentState(JS::gcreason::Reason reason)
return true;
}
+bool
+GCRuntime::shouldRepeatForDeadZone(JS::gcreason::Reason reason)
+{
+ MOZ_ASSERT_IF(reason == JS::gcreason::COMPARTMENT_REVIVED, !isIncremental);
+
+ if (!isIncremental || isIncrementalGCInProgress())
+ return false;
+
+ for (CompartmentsIter c(rt, SkipAtoms); !c.done(); c.next()) {
+ if (c->scheduledForDestruction)
+ return true;
+ }
+
+ return false;
+}
+
void
GCRuntime::collect(bool nonincrementalByAPI, SliceBudget budget, JS::gcreason::Reason reason)
{
@@ -5777,27 +5808,23 @@ GCRuntime::collect(bool nonincrementalByAPI, SliceBudget budget, JS::gcreason::R
do {
poked = false;
bool wasReset = gcCycle(nonincrementalByAPI, budget, reason);
-
- /* Need to re-schedule all zones for GC. */
- if (poked && cleanUpEverything)
+
+ bool repeatForDeadZone = false;
+ if (poked && cleanUpEverything) {
+ /* Need to re-schedule all zones for GC. */
JS::PrepareForFullGC(rt->contextFromMainThread());
- /*
- * This code makes an extra effort to collect compartments that we
- * thought were dead at the start of the GC. See the large comment in
- * beginMarkPhase.
- */
- bool repeatForDeadZone = false;
- if (!nonincrementalByAPI && !isIncrementalGCInProgress()) {
- for (CompartmentsIter c(rt, SkipAtoms); !c.done(); c.next()) {
- if (c->scheduledForDestruction) {
- nonincrementalByAPI = true;
- repeatForDeadZone = true;
- reason = JS::gcreason::COMPARTMENT_REVIVED;
- c->zone()->scheduleGC();
- }
- }
+
+ } else if (shouldRepeatForDeadZone(reason) && !wasReset) {
+ /*
+ * This code makes an extra effort to collect compartments that we
+ * thought were dead at the start of the GC. See the large comment
+ * in beginMarkPhase.
+ */
+ repeatForDeadZone = true;
+ reason = JS::gcreason::COMPARTMENT_REVIVED;
}
+
/*
* If we reset an existing GC, we need to start a new one. Also, we
@@ -6149,12 +6176,6 @@ gc::MergeCompartments(JSCompartment* source, JSCompartment* target)
for (auto group = source->zone()->cellIter<ObjectGroup>(); !group.done(); group.next()) {
group->setGeneration(target->zone()->types.generation);
group->compartment_ = target;
-
- // Remove any unboxed layouts from the list in the off thread
- // compartment. These do not need to be reinserted in the target
- // compartment's list, as the list is not required to be complete.
- if (UnboxedLayout* layout = group->maybeUnboxedLayoutDontCheckGeneration())
- layout->detachFromCompartment();
}
// Fixup zone pointers in source's zone to refer to target's zone.
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-23 08:24:26 +0000