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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* 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/. */
/*
* JS engine garbage collector API.
*/
#ifndef gc_GC_h
#define gc_GC_h
#include "gc/AllocKind.h"
#include "gc/GCEnum.h"
#include "js/GCAPI.h"
#include "js/HeapAPI.h"
#include "js/RealmIterators.h"
#include "js/TraceKind.h"
class JSTracer;
namespace JS {
class RealmOptions;
}
namespace js {
class Nursery;
namespace gc {
class Arena;
class TenuredChunk;
} /* namespace gc */
// Define name, key and writability for the GC parameters.
#define FOR_EACH_GC_PARAM(_) \
_("maxBytes", JSGC_MAX_BYTES, true) \
_("minNurseryBytes", JSGC_MIN_NURSERY_BYTES, true) \
_("maxNurseryBytes", JSGC_MAX_NURSERY_BYTES, true) \
_("gcBytes", JSGC_BYTES, false) \
_("nurseryBytes", JSGC_NURSERY_BYTES, false) \
_("gcNumber", JSGC_NUMBER, false) \
_("majorGCNumber", JSGC_MAJOR_GC_NUMBER, false) \
_("minorGCNumber", JSGC_MINOR_GC_NUMBER, false) \
_("incrementalGCEnabled", JSGC_INCREMENTAL_GC_ENABLED, true) \
_("perZoneGCEnabled", JSGC_PER_ZONE_GC_ENABLED, true) \
_("unusedChunks", JSGC_UNUSED_CHUNKS, false) \
_("totalChunks", JSGC_TOTAL_CHUNKS, false) \
_("sliceTimeBudgetMS", JSGC_SLICE_TIME_BUDGET_MS, true) \
_("highFrequencyTimeLimit", JSGC_HIGH_FREQUENCY_TIME_LIMIT, true) \
_("smallHeapSizeMax", JSGC_SMALL_HEAP_SIZE_MAX, true) \
_("largeHeapSizeMin", JSGC_LARGE_HEAP_SIZE_MIN, true) \
_("highFrequencySmallHeapGrowth", JSGC_HIGH_FREQUENCY_SMALL_HEAP_GROWTH, \
true) \
_("highFrequencyLargeHeapGrowth", JSGC_HIGH_FREQUENCY_LARGE_HEAP_GROWTH, \
true) \
_("lowFrequencyHeapGrowth", JSGC_LOW_FREQUENCY_HEAP_GROWTH, true) \
_("balancedHeapLimitsEnabled", JSGC_BALANCED_HEAP_LIMITS_ENABLED, true) \
_("heapGrowthFactor", JSGC_HEAP_GROWTH_FACTOR, true) \
_("allocationThreshold", JSGC_ALLOCATION_THRESHOLD, true) \
_("smallHeapIncrementalLimit", JSGC_SMALL_HEAP_INCREMENTAL_LIMIT, true) \
_("largeHeapIncrementalLimit", JSGC_LARGE_HEAP_INCREMENTAL_LIMIT, true) \
_("minEmptyChunkCount", JSGC_MIN_EMPTY_CHUNK_COUNT, true) \
_("maxEmptyChunkCount", JSGC_MAX_EMPTY_CHUNK_COUNT, true) \
_("compactingEnabled", JSGC_COMPACTING_ENABLED, true) \
_("parallelMarkingEnabled", JSGC_PARALLEL_MARKING_ENABLED, true) \
_("parallelMarkingThresholdMB", JSGC_PARALLEL_MARKING_THRESHOLD_MB, true) \
_("minLastDitchGCPeriod", JSGC_MIN_LAST_DITCH_GC_PERIOD, true) \
_("nurseryEagerCollectionThresholdKB", \
JSGC_NURSERY_EAGER_COLLECTION_THRESHOLD_KB, true) \
_("nurseryEagerCollectionThresholdPercent", \
JSGC_NURSERY_EAGER_COLLECTION_THRESHOLD_PERCENT, true) \
_("nurseryEagerCollectionTimeoutMS", \
JSGC_NURSERY_EAGER_COLLECTION_TIMEOUT_MS, true) \
_("zoneAllocDelayKB", JSGC_ZONE_ALLOC_DELAY_KB, true) \
_("mallocThresholdBase", JSGC_MALLOC_THRESHOLD_BASE, true) \
_("urgentThreshold", JSGC_URGENT_THRESHOLD_MB, true) \
_("chunkBytes", JSGC_CHUNK_BYTES, false) \
_("helperThreadRatio", JSGC_HELPER_THREAD_RATIO, true) \
_("maxHelperThreads", JSGC_MAX_HELPER_THREADS, true) \
_("helperThreadCount", JSGC_HELPER_THREAD_COUNT, false) \
_("markingThreadCount", JSGC_MARKING_THREAD_COUNT, true) \
_("systemPageSizeKB", JSGC_SYSTEM_PAGE_SIZE_KB, false)
// Get the key and writability give a GC parameter name.
extern bool GetGCParameterInfo(const char* name, JSGCParamKey* keyOut,
bool* writableOut);
extern void TraceRuntime(JSTracer* trc);
// Trace roots but don't evict the nursery first; used from DumpHeap.
extern void TraceRuntimeWithoutEviction(JSTracer* trc);
extern void ReleaseAllJITCode(JS::GCContext* gcx);
extern void PrepareForDebugGC(JSRuntime* rt);
/* Functions for managing cross compartment gray pointers. */
extern void NotifyGCNukeWrapper(JSContext* cx, JSObject* wrapper);
extern unsigned NotifyGCPreSwap(JSObject* a, JSObject* b);
extern void NotifyGCPostSwap(JSObject* a, JSObject* b, unsigned removedFlags);
using IterateChunkCallback = void (*)(JSRuntime*, void*, gc::TenuredChunk*,
const JS::AutoRequireNoGC&);
using IterateZoneCallback = void (*)(JSRuntime*, void*, JS::Zone*,
const JS::AutoRequireNoGC&);
using IterateArenaCallback = void (*)(JSRuntime*, void*, gc::Arena*,
JS::TraceKind, size_t,
const JS::AutoRequireNoGC&);
using IterateCellCallback = void (*)(JSRuntime*, void*, JS::GCCellPtr, size_t,
const JS::AutoRequireNoGC&);
/*
* This function calls |zoneCallback| on every zone, |realmCallback| on
* every realm, |arenaCallback| on every in-use arena, and |cellCallback|
* on every in-use cell in the GC heap.
*
* Note that no read barrier is triggered on the cells passed to cellCallback,
* so no these pointers must not escape the callback.
*/
extern void IterateHeapUnbarriered(JSContext* cx, void* data,
IterateZoneCallback zoneCallback,
JS::IterateRealmCallback realmCallback,
IterateArenaCallback arenaCallback,
IterateCellCallback cellCallback);
/*
* This function is like IterateHeapUnbarriered, but does it for a single zone.
*/
extern void IterateHeapUnbarrieredForZone(
JSContext* cx, JS::Zone* zone, void* data, IterateZoneCallback zoneCallback,
JS::IterateRealmCallback realmCallback, IterateArenaCallback arenaCallback,
IterateCellCallback cellCallback);
/*
* Invoke chunkCallback on every in-use chunk.
*/
extern void IterateChunks(JSContext* cx, void* data,
IterateChunkCallback chunkCallback);
using IterateScriptCallback = void (*)(JSRuntime*, void*, BaseScript*,
const JS::AutoRequireNoGC&);
/*
* Invoke scriptCallback on every in-use script for the given realm or for all
* realms if it is null. The scripts may or may not have bytecode.
*/
extern void IterateScripts(JSContext* cx, JS::Realm* realm, void* data,
IterateScriptCallback scriptCallback);
JS::Realm* NewRealm(JSContext* cx, JSPrincipals* principals,
const JS::RealmOptions& options);
namespace gc {
void FinishGC(JSContext* cx, JS::GCReason = JS::GCReason::FINISH_GC);
void WaitForBackgroundTasks(JSContext* cx);
enum VerifierType { PreBarrierVerifier };
#ifdef JS_GC_ZEAL
extern const char ZealModeHelpText[];
/* Check that write barriers have been used correctly. See gc/Verifier.cpp. */
void VerifyBarriers(JSRuntime* rt, VerifierType type);
void MaybeVerifyBarriers(JSContext* cx, bool always = false);
void DumpArenaInfo();
#else
static inline void VerifyBarriers(JSRuntime* rt, VerifierType type) {}
static inline void MaybeVerifyBarriers(JSContext* cx, bool always = false) {}
#endif
/*
* Instances of this class prevent GC from happening while they are live. If an
* allocation causes a heap threshold to be exceeded, no GC will be performed
* and the allocation will succeed. Allocation may still fail for other reasons.
*
* Use of this class is highly discouraged, since without GC system memory can
* become exhausted and this can cause crashes at places where we can't handle
* allocation failure.
*
* Use of this is permissible in situations where it would be impossible (or at
* least very difficult) to tolerate GC and where only a fixed number of objects
* are allocated, such as:
*
* - error reporting
* - JIT bailout handling
* - brain transplants (JSObject::swap)
* - debugging utilities not exposed to the browser
*
* This works by updating the |JSContext::suppressGC| counter which is checked
* at the start of GC.
*/
class MOZ_RAII JS_HAZ_GC_SUPPRESSED AutoSuppressGC
: public JS::AutoRequireNoGC {
int32_t& suppressGC_;
public:
explicit AutoSuppressGC(JSContext* cx);
~AutoSuppressGC() { suppressGC_--; }
};
const char* StateName(State state);
} /* namespace gc */
/* Use this to avoid assertions when manipulating the wrapper map. */
class MOZ_RAII AutoDisableProxyCheck {
public:
#ifdef DEBUG
AutoDisableProxyCheck();
~AutoDisableProxyCheck();
#else
AutoDisableProxyCheck() {}
#endif
};
struct MOZ_RAII AutoDisableCompactingGC {
explicit AutoDisableCompactingGC(JSContext* cx);
~AutoDisableCompactingGC();
private:
JSContext* cx;
};
/*
* Dynamically select the GC heap to allocate into for a graph of GC things.
*
* Initially |heap()| will return Heap::Default to select nursery allocation,
* but when a specified number of nursery collections have been triggered it
* switches to returning Heap::Tenured.
*/
class MOZ_RAII AutoSelectGCHeap {
public:
explicit AutoSelectGCHeap(JSContext* cx,
size_t allowedNurseryCollections = 0);
~AutoSelectGCHeap();
gc::Heap heap() const { return heap_; }
operator gc::Heap() const { return heap_; }
void onNurseryCollectionEnd();
private:
static void NurseryCollectionCallback(JSContext* cx,
JS::GCNurseryProgress progress,
JS::GCReason reason, void* data);
JSContext* cx_;
size_t allowedNurseryCollections_;
gc::Heap heap_ = gc::Heap::Default;
};
} /* namespace js */
#endif /* gc_GC_h */
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