https://github.com/mozilla/gecko-dev
Tip revision: 43dffdc333867ea60702078cae26680e7bcda33e authored by Jeff Muizelaar on 10 November 2014, 21:11:42 UTC
Bug 1021265 - Fix DisplayLink version expansion code. r=Bas, a=sledru
Bug 1021265 - Fix DisplayLink version expansion code. r=Bas, a=sledru
Tip revision: 43dffdc
jsgcinlines.h
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef jsgcinlines_h
#define jsgcinlines_h
#include "jsgc.h"
#include "gc/GCTrace.h"
#include "gc/Zone.h"
#include "vm/ForkJoin.h"
namespace js {
class Shape;
/*
* This auto class should be used around any code that might cause a mark bit to
* be set on an object in a dead zone. See AutoMaybeTouchDeadZones
* for more details.
*/
struct AutoMarkInDeadZone
{
explicit AutoMarkInDeadZone(JS::Zone *zone)
: zone(zone),
scheduled(zone->scheduledForDestruction)
{
gc::GCRuntime &gc = zone->runtimeFromMainThread()->gc;
if (gc.isManipulatingDeadZones() && zone->scheduledForDestruction) {
gc.incObjectsMarkedInDeadZone();
zone->scheduledForDestruction = false;
}
}
~AutoMarkInDeadZone() {
zone->scheduledForDestruction = scheduled;
}
private:
JS::Zone *zone;
bool scheduled;
};
inline Allocator *
ThreadSafeContext::allocator() const
{
JS_ASSERT_IF(isJSContext(), &asJSContext()->zone()->allocator == allocator_);
return allocator_;
}
template <typename T>
inline bool
ThreadSafeContext::isThreadLocal(T thing) const
{
if (!isForkJoinContext())
return true;
#ifdef JSGC_FJGENERATIONAL
ForkJoinContext *cx = static_cast<ForkJoinContext*>(const_cast<ThreadSafeContext*>(this));
if (cx->nursery().isInsideNewspace(thing))
return true;
#endif
// Global invariant
JS_ASSERT(!IsInsideNursery(thing));
// The thing is not in the nursery, but is it in the private tenured area?
if (allocator_->arenas.containsArena(runtime_, thing->arenaHeader()))
{
// GC should be suppressed in preparation for mutating thread local
// objects, as we don't want to trip any barriers.
JS_ASSERT(!thing->zoneFromAnyThread()->needsBarrier());
JS_ASSERT(!thing->runtimeFromAnyThread()->needsBarrier());
return true;
}
return false;
}
namespace gc {
static inline AllocKind
GetGCObjectKind(const Class *clasp)
{
if (clasp == FunctionClassPtr)
return JSFunction::FinalizeKind;
uint32_t nslots = JSCLASS_RESERVED_SLOTS(clasp);
if (clasp->flags & JSCLASS_HAS_PRIVATE)
nslots++;
return GetGCObjectKind(nslots);
}
#ifdef JSGC_GENERATIONAL
inline bool
ShouldNurseryAllocate(const Nursery &nursery, AllocKind kind, InitialHeap heap)
{
return nursery.isEnabled() && IsNurseryAllocable(kind) && heap != TenuredHeap;
}
#endif
#ifdef JSGC_FJGENERATIONAL
inline bool
ShouldFJNurseryAllocate(const ForkJoinNursery &nursery, AllocKind kind, InitialHeap heap)
{
return IsFJNurseryAllocable(kind) && heap != TenuredHeap;
}
#endif
inline JSGCTraceKind
GetGCThingTraceKind(const void *thing)
{
JS_ASSERT(thing);
const Cell *cell = static_cast<const Cell *>(thing);
#ifdef JSGC_GENERATIONAL
if (IsInsideNursery(cell))
return JSTRACE_OBJECT;
#endif
return MapAllocToTraceKind(cell->tenuredGetAllocKind());
}
inline void
GCRuntime::poke()
{
poked = true;
#ifdef JS_GC_ZEAL
/* Schedule a GC to happen "soon" after a GC poke. */
if (zealMode == ZealPokeValue)
nextScheduled = 1;
#endif
}
class ArenaIter
{
ArenaHeader *aheader;
ArenaHeader *unsweptHeader;
ArenaHeader *sweptHeader;
public:
ArenaIter() {
aheader = nullptr;
unsweptHeader = nullptr;
sweptHeader = nullptr;
}
ArenaIter(JS::Zone *zone, AllocKind kind) {
init(zone, kind);
}
void init(Allocator *allocator, AllocKind kind) {
aheader = allocator->arenas.getFirstArena(kind);
unsweptHeader = allocator->arenas.getFirstArenaToSweep(kind);
sweptHeader = allocator->arenas.getFirstSweptArena(kind);
if (!unsweptHeader) {
unsweptHeader = sweptHeader;
sweptHeader = nullptr;
}
if (!aheader) {
aheader = unsweptHeader;
unsweptHeader = sweptHeader;
sweptHeader = nullptr;
}
}
void init(JS::Zone *zone, AllocKind kind) {
init(&zone->allocator, kind);
}
bool done() const {
return !aheader;
}
ArenaHeader *get() const {
return aheader;
}
void next() {
JS_ASSERT(!done());
aheader = aheader->next;
if (!aheader) {
aheader = unsweptHeader;
unsweptHeader = sweptHeader;
sweptHeader = nullptr;
}
}
};
class ArenaCellIterImpl
{
// These three are set in initUnsynchronized().
size_t firstThingOffset;
size_t thingSize;
#ifdef DEBUG
bool isInited;
#endif
// These three are set in reset() (which is called by init()).
FreeSpan span;
uintptr_t thing;
uintptr_t limit;
// Upon entry, |thing| points to any thing (free or used) and finds the
// first used thing, which may be |thing|.
void moveForwardIfFree() {
JS_ASSERT(!done());
JS_ASSERT(thing);
// Note: if |span| is empty, this test will fail, which is what we want
// -- |span| being empty means that we're past the end of the last free
// thing, all the remaining things in the arena are used, and we'll
// never need to move forward.
if (thing == span.first) {
thing = span.last + thingSize;
span = *span.nextSpan();
}
}
public:
ArenaCellIterImpl()
: firstThingOffset(0) // Squelch
, thingSize(0) // warnings
{
}
void initUnsynchronized(ArenaHeader *aheader) {
AllocKind kind = aheader->getAllocKind();
#ifdef DEBUG
isInited = true;
#endif
firstThingOffset = Arena::firstThingOffset(kind);
thingSize = Arena::thingSize(kind);
reset(aheader);
}
void init(ArenaHeader *aheader) {
#ifdef DEBUG
AllocKind kind = aheader->getAllocKind();
JS_ASSERT(aheader->zone->allocator.arenas.isSynchronizedFreeList(kind));
#endif
initUnsynchronized(aheader);
}
// Use this to move from an Arena of a particular kind to another Arena of
// the same kind.
void reset(ArenaHeader *aheader) {
JS_ASSERT(isInited);
span = aheader->getFirstFreeSpan();
uintptr_t arenaAddr = aheader->arenaAddress();
thing = arenaAddr + firstThingOffset;
limit = arenaAddr + ArenaSize;
moveForwardIfFree();
}
bool done() const {
return thing == limit;
}
Cell *getCell() const {
JS_ASSERT(!done());
return reinterpret_cast<Cell *>(thing);
}
template<typename T> T *get() const {
JS_ASSERT(!done());
return static_cast<T *>(getCell());
}
void next() {
MOZ_ASSERT(!done());
thing += thingSize;
if (thing < limit)
moveForwardIfFree();
}
};
class ArenaCellIterUnderGC : public ArenaCellIterImpl
{
public:
explicit ArenaCellIterUnderGC(ArenaHeader *aheader) {
JS_ASSERT(aheader->zone->runtimeFromAnyThread()->isHeapBusy());
init(aheader);
}
};
class ArenaCellIterUnderFinalize : public ArenaCellIterImpl
{
public:
explicit ArenaCellIterUnderFinalize(ArenaHeader *aheader) {
initUnsynchronized(aheader);
}
};
class ZoneCellIterImpl
{
ArenaIter arenaIter;
ArenaCellIterImpl cellIter;
protected:
ZoneCellIterImpl() {}
void init(JS::Zone *zone, AllocKind kind) {
JS_ASSERT(zone->allocator.arenas.isSynchronizedFreeList(kind));
arenaIter.init(zone, kind);
if (!arenaIter.done())
cellIter.init(arenaIter.get());
}
public:
bool done() const {
return arenaIter.done();
}
template<typename T> T *get() const {
JS_ASSERT(!done());
return cellIter.get<T>();
}
Cell *getCell() const {
JS_ASSERT(!done());
return cellIter.getCell();
}
void next() {
JS_ASSERT(!done());
cellIter.next();
if (cellIter.done()) {
JS_ASSERT(!arenaIter.done());
arenaIter.next();
if (!arenaIter.done())
cellIter.reset(arenaIter.get());
}
}
};
class ZoneCellIterUnderGC : public ZoneCellIterImpl
{
public:
ZoneCellIterUnderGC(JS::Zone *zone, AllocKind kind) {
#ifdef JSGC_GENERATIONAL
JS_ASSERT(zone->runtimeFromAnyThread()->gc.nursery.isEmpty());
#endif
JS_ASSERT(zone->runtimeFromAnyThread()->isHeapBusy());
init(zone, kind);
}
};
/* In debug builds, assert that no allocation occurs. */
class AutoAssertNoAlloc
{
#ifdef JS_DEBUG
GCRuntime *gc;
public:
AutoAssertNoAlloc() : gc(nullptr) {}
explicit AutoAssertNoAlloc(JSRuntime *rt) : gc(nullptr) {
disallowAlloc(rt);
}
void disallowAlloc(JSRuntime *rt) {
JS_ASSERT(!gc);
gc = &rt->gc;
gc->disallowAlloc();
}
~AutoAssertNoAlloc() {
if (gc)
gc->allowAlloc();
}
#else
public:
AutoAssertNoAlloc() {}
explicit AutoAssertNoAlloc(JSRuntime *) {}
void disallowAlloc(JSRuntime *rt) {}
#endif
};
class ZoneCellIter : public ZoneCellIterImpl
{
AutoAssertNoAlloc noAlloc;
ArenaLists *lists;
AllocKind kind;
public:
ZoneCellIter(JS::Zone *zone, AllocKind kind)
: lists(&zone->allocator.arenas),
kind(kind)
{
/*
* We have a single-threaded runtime, so there's no need to protect
* against other threads iterating or allocating. However, we do have
* background finalization; we have to wait for this to finish if it's
* currently active.
*/
if (IsBackgroundFinalized(kind) &&
zone->allocator.arenas.needBackgroundFinalizeWait(kind))
{
gc::FinishBackgroundFinalize(zone->runtimeFromMainThread());
}
#ifdef JSGC_GENERATIONAL
/* Evict the nursery before iterating so we can see all things. */
JSRuntime *rt = zone->runtimeFromMainThread();
if (!rt->gc.nursery.isEmpty())
MinorGC(rt, JS::gcreason::EVICT_NURSERY);
#endif
if (lists->isSynchronizedFreeList(kind)) {
lists = nullptr;
} else {
JS_ASSERT(!zone->runtimeFromMainThread()->isHeapBusy());
lists->copyFreeListToArena(kind);
}
/* Assert that no GCs can occur while a ZoneCellIter is live. */
noAlloc.disallowAlloc(zone->runtimeFromMainThread());
init(zone, kind);
}
~ZoneCellIter() {
if (lists)
lists->clearFreeListInArena(kind);
}
};
class GCZonesIter
{
private:
ZonesIter zone;
public:
explicit GCZonesIter(JSRuntime *rt) : zone(rt, WithAtoms) {
if (!zone->isCollecting())
next();
}
bool done() const { return zone.done(); }
void next() {
JS_ASSERT(!done());
do {
zone.next();
} while (!zone.done() && !zone->isCollecting());
}
JS::Zone *get() const {
JS_ASSERT(!done());
return zone;
}
operator JS::Zone *() const { return get(); }
JS::Zone *operator->() const { return get(); }
};
typedef CompartmentsIterT<GCZonesIter> GCCompartmentsIter;
/* Iterates over all zones in the current zone group. */
class GCZoneGroupIter {
private:
JS::Zone *current;
public:
explicit GCZoneGroupIter(JSRuntime *rt) {
JS_ASSERT(rt->isHeapBusy());
current = rt->gc.getCurrentZoneGroup();
}
bool done() const { return !current; }
void next() {
JS_ASSERT(!done());
current = current->nextNodeInGroup();
}
JS::Zone *get() const {
JS_ASSERT(!done());
return current;
}
operator JS::Zone *() const { return get(); }
JS::Zone *operator->() const { return get(); }
};
typedef CompartmentsIterT<GCZoneGroupIter> GCCompartmentGroupIter;
#ifdef JSGC_GENERATIONAL
/*
* Attempt to allocate a new GC thing out of the nursery. If there is not enough
* room in the nursery or there is an OOM, this method will return nullptr.
*/
template <AllowGC allowGC>
inline JSObject *
TryNewNurseryObject(JSContext *cx, size_t thingSize, size_t nDynamicSlots)
{
JS_ASSERT(!IsAtomsCompartment(cx->compartment()));
JSRuntime *rt = cx->runtime();
Nursery &nursery = rt->gc.nursery;
JSObject *obj = nursery.allocateObject(cx, thingSize, nDynamicSlots);
if (obj)
return obj;
if (allowGC && !rt->mainThread.suppressGC) {
MinorGC(cx, JS::gcreason::OUT_OF_NURSERY);
/* Exceeding gcMaxBytes while tenuring can disable the Nursery. */
if (nursery.isEnabled()) {
JSObject *obj = nursery.allocateObject(cx, thingSize, nDynamicSlots);
JS_ASSERT(obj);
return obj;
}
}
return nullptr;
}
#endif /* JSGC_GENERATIONAL */
#ifdef JSGC_FJGENERATIONAL
template <AllowGC allowGC>
inline JSObject *
TryNewNurseryObject(ForkJoinContext *cx, size_t thingSize, size_t nDynamicSlots)
{
ForkJoinNursery &nursery = cx->nursery();
bool tooLarge = false;
JSObject *obj = nursery.allocateObject(thingSize, nDynamicSlots, tooLarge);
if (obj)
return obj;
if (!tooLarge && allowGC) {
nursery.minorGC();
obj = nursery.allocateObject(thingSize, nDynamicSlots, tooLarge);
if (obj)
return obj;
}
return nullptr;
}
#endif /* JSGC_FJGENERATIONAL */
static inline bool
PossiblyFail()
{
JS_OOM_POSSIBLY_FAIL();
return true;
}
template <AllowGC allowGC>
static inline bool
CheckAllocatorState(ThreadSafeContext *cx, AllocKind kind)
{
if (!cx->isJSContext())
return true;
JSContext *ncx = cx->asJSContext();
JSRuntime *rt = ncx->runtime();
#if defined(JS_GC_ZEAL) || defined(DEBUG)
JS_ASSERT_IF(rt->isAtomsCompartment(ncx->compartment()),
kind == FINALIZE_STRING ||
kind == FINALIZE_FAT_INLINE_STRING ||
kind == FINALIZE_SYMBOL ||
kind == FINALIZE_JITCODE);
JS_ASSERT(!rt->isHeapBusy());
JS_ASSERT(rt->gc.isAllocAllowed());
#endif
// Crash if we perform a GC action when it is not safe.
if (allowGC && !rt->mainThread.suppressGC)
JS::AutoAssertOnGC::VerifyIsSafeToGC(rt);
// For testing out of memory conditions
if (!PossiblyFail()) {
js_ReportOutOfMemory(cx);
return false;
}
if (allowGC) {
#ifdef JS_GC_ZEAL
if (rt->gc.needZealousGC())
js::gc::RunDebugGC(ncx);
#endif
if (rt->interrupt) {
// Invoking the interrupt callback can fail and we can't usefully
// handle that here. Just check in case we need to collect instead.
js::gc::GCIfNeeded(ncx);
}
}
return true;
}
template <typename T>
static inline void
CheckIncrementalZoneState(ThreadSafeContext *cx, T *t)
{
#ifdef DEBUG
if (!cx->isJSContext())
return;
Zone *zone = cx->asJSContext()->zone();
JS_ASSERT_IF(t && zone->wasGCStarted() && (zone->isGCMarking() || zone->isGCSweeping()),
t->arenaHeader()->allocatedDuringIncremental);
#endif
}
/*
* Allocate a new GC thing. After a successful allocation the caller must
* fully initialize the thing before calling any function that can potentially
* trigger GC. This will ensure that GC tracing never sees junk values stored
* in the partially initialized thing.
*/
template <AllowGC allowGC>
inline JSObject *
AllocateObject(ThreadSafeContext *cx, AllocKind kind, size_t nDynamicSlots, InitialHeap heap)
{
size_t thingSize = Arena::thingSize(kind);
JS_ASSERT(thingSize == Arena::thingSize(kind));
JS_ASSERT(thingSize >= sizeof(JSObject));
static_assert(sizeof(JSObject) >= CellSize,
"All allocations must be at least the allocator-imposed minimum size.");
if (!CheckAllocatorState<allowGC>(cx, kind))
return nullptr;
#ifdef JSGC_GENERATIONAL
if (cx->isJSContext() &&
ShouldNurseryAllocate(cx->asJSContext()->nursery(), kind, heap)) {
JSObject *obj = TryNewNurseryObject<allowGC>(cx->asJSContext(), thingSize, nDynamicSlots);
if (obj)
return obj;
}
#endif
#ifdef JSGC_FJGENERATIONAL
if (cx->isForkJoinContext() &&
ShouldFJNurseryAllocate(cx->asForkJoinContext()->nursery(), kind, heap))
{
JSObject *obj =
TryNewNurseryObject<allowGC>(cx->asForkJoinContext(), thingSize, nDynamicSlots);
if (obj)
return obj;
}
#endif
HeapSlot *slots = nullptr;
if (nDynamicSlots) {
slots = cx->pod_malloc<HeapSlot>(nDynamicSlots);
if (MOZ_UNLIKELY(!slots))
return nullptr;
js::Debug_SetSlotRangeToCrashOnTouch(slots, nDynamicSlots);
}
JSObject *obj = static_cast<JSObject *>(cx->allocator()->arenas.allocateFromFreeList(kind, thingSize));
if (!obj)
obj = static_cast<JSObject *>(js::gc::ArenaLists::refillFreeList<allowGC>(cx, kind));
if (obj)
obj->setInitialSlots(slots);
else
js_free(slots);
CheckIncrementalZoneState(cx, obj);
js::gc::TraceTenuredAlloc(obj, kind);
return obj;
}
template <typename T, AllowGC allowGC>
inline T *
AllocateNonObject(ThreadSafeContext *cx)
{
static_assert(sizeof(T) >= CellSize,
"All allocations must be at least the allocator-imposed minimum size.");
AllocKind kind = MapTypeToFinalizeKind<T>::kind;
size_t thingSize = sizeof(T);
JS_ASSERT(thingSize == Arena::thingSize(kind));
if (!CheckAllocatorState<allowGC>(cx, kind))
return nullptr;
T *t = static_cast<T *>(cx->allocator()->arenas.allocateFromFreeList(kind, thingSize));
if (!t)
t = static_cast<T *>(js::gc::ArenaLists::refillFreeList<allowGC>(cx, kind));
CheckIncrementalZoneState(cx, t);
js::gc::TraceTenuredAlloc(t, kind);
return t;
}
/*
* When allocating for initialization from a cached object copy, we will
* potentially destroy the cache entry we want to copy if we allow GC. On the
* other hand, since these allocations are extremely common, we don't want to
* delay GC from these allocation sites. Instead we allow the GC, but still
* fail the allocation, forcing the non-cached path.
*
* Observe this won't be used for ForkJoin allocation, as it takes a JSContext*
*/
template <AllowGC allowGC>
inline JSObject *
AllocateObjectForCacheHit(JSContext *cx, AllocKind kind, InitialHeap heap)
{
#ifdef JSGC_GENERATIONAL
if (ShouldNurseryAllocate(cx->nursery(), kind, heap)) {
size_t thingSize = Arena::thingSize(kind);
JS_ASSERT(thingSize == Arena::thingSize(kind));
if (!CheckAllocatorState<NoGC>(cx, kind))
return nullptr;
JSObject *obj = TryNewNurseryObject<NoGC>(cx, thingSize, 0);
if (!obj && allowGC) {
MinorGC(cx, JS::gcreason::OUT_OF_NURSERY);
return nullptr;
}
return obj;
}
#endif
JSObject *obj = AllocateObject<NoGC>(cx, kind, 0, heap);
if (!obj && allowGC) {
MaybeGC(cx);
return nullptr;
}
return obj;
}
inline bool
IsInsideGGCNursery(const js::gc::Cell *cell)
{
#ifdef JSGC_GENERATIONAL
if (!cell)
return false;
uintptr_t addr = uintptr_t(cell);
addr &= ~js::gc::ChunkMask;
addr |= js::gc::ChunkLocationOffset;
uint32_t location = *reinterpret_cast<uint32_t *>(addr);
JS_ASSERT(location != 0);
return location & js::gc::ChunkLocationBitNursery;
#else
return false;
#endif
}
} /* namespace gc */
template <js::AllowGC allowGC>
inline JSObject *
NewGCObject(js::ThreadSafeContext *cx, js::gc::AllocKind kind, size_t nDynamicSlots, js::gc::InitialHeap heap)
{
JS_ASSERT(kind >= js::gc::FINALIZE_OBJECT0 && kind <= js::gc::FINALIZE_OBJECT_LAST);
return js::gc::AllocateObject<allowGC>(cx, kind, nDynamicSlots, heap);
}
template <js::AllowGC allowGC>
inline jit::JitCode *
NewJitCode(js::ThreadSafeContext *cx)
{
return gc::AllocateNonObject<jit::JitCode, allowGC>(cx);
}
inline
types::TypeObject *
NewTypeObject(js::ThreadSafeContext *cx)
{
return gc::AllocateNonObject<types::TypeObject, js::CanGC>(cx);
}
template <js::AllowGC allowGC>
inline JSString *
NewGCString(js::ThreadSafeContext *cx)
{
return js::gc::AllocateNonObject<JSString, allowGC>(cx);
}
template <js::AllowGC allowGC>
inline JSFatInlineString *
NewGCFatInlineString(js::ThreadSafeContext *cx)
{
return js::gc::AllocateNonObject<JSFatInlineString, allowGC>(cx);
}
inline JSExternalString *
NewGCExternalString(js::ThreadSafeContext *cx)
{
return js::gc::AllocateNonObject<JSExternalString, js::CanGC>(cx);
}
} /* namespace js */
inline JSScript *
js_NewGCScript(js::ThreadSafeContext *cx)
{
return js::gc::AllocateNonObject<JSScript, js::CanGC>(cx);
}
inline js::LazyScript *
js_NewGCLazyScript(js::ThreadSafeContext *cx)
{
return js::gc::AllocateNonObject<js::LazyScript, js::CanGC>(cx);
}
inline js::Shape *
js_NewGCShape(js::ThreadSafeContext *cx)
{
return js::gc::AllocateNonObject<js::Shape, js::CanGC>(cx);
}
template <js::AllowGC allowGC>
inline js::BaseShape *
js_NewGCBaseShape(js::ThreadSafeContext *cx)
{
return js::gc::AllocateNonObject<js::BaseShape, allowGC>(cx);
}
#endif /* jsgcinlines_h */