mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-24 21:31:04 +00:00
4c52aa4d3f
Notice as TimeStamp is not an integral type, it can't be wrapped by mozilla::Atomic. However, we wrap it in MainThreadData to assure it only is accessed from the main thread. Another issue is that TimeStamp class does allow some operations on a Null value, with assertions on debug builds. MozReview-Commit-ID: 9GPNDUooQmI --HG-- extra : rebase_source : e2b5fe81a4c5c696425583a04395f2ae79aeaccc
1040 lines
33 KiB
C++
1040 lines
33 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* vim: set ts=8 sts=4 et sw=4 tw=99:
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/*
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* High-level interface to the JS garbage collector.
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*/
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#ifndef js_GCAPI_h
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#define js_GCAPI_h
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#include "mozilla/TimeStamp.h"
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#include "mozilla/Vector.h"
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#include "js/GCAnnotations.h"
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#include "js/TypeDecls.h"
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#include "js/UniquePtr.h"
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#include "js/Utility.h"
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struct JSFreeOp;
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#ifdef JS_BROKEN_GCC_ATTRIBUTE_WARNING
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wattributes"
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#endif // JS_BROKEN_GCC_ATTRIBUTE_WARNING
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class JS_PUBLIC_API(JSTracer);
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#ifdef JS_BROKEN_GCC_ATTRIBUTE_WARNING
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#pragma GCC diagnostic pop
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#endif // JS_BROKEN_GCC_ATTRIBUTE_WARNING
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namespace js {
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namespace gc {
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class GCRuntime;
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} // namespace gc
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namespace gcstats {
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struct Statistics;
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} // namespace gcstats
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} // namespace js
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typedef enum JSGCMode {
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/** Perform only global GCs. */
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JSGC_MODE_GLOBAL = 0,
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/** Perform per-zone GCs until too much garbage has accumulated. */
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JSGC_MODE_ZONE = 1,
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/**
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* Collect in short time slices rather than all at once. Implies
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* JSGC_MODE_ZONE.
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*/
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JSGC_MODE_INCREMENTAL = 2
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} JSGCMode;
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/**
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* Kinds of js_GC invocation.
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*/
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typedef enum JSGCInvocationKind {
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/* Normal invocation. */
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GC_NORMAL = 0,
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/* Minimize GC triggers and release empty GC chunks right away. */
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GC_SHRINK = 1
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} JSGCInvocationKind;
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typedef enum JSGCParamKey {
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/**
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* Maximum nominal heap before last ditch GC.
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*
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* Soft limit on the number of bytes we are allowed to allocate in the GC
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* heap. Attempts to allocate gcthings over this limit will return null and
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* subsequently invoke the standard OOM machinery, independent of available
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* physical memory.
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*
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* Pref: javascript.options.mem.max
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* Default: 0xffffffff
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*/
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JSGC_MAX_BYTES = 0,
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/**
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* Initial value for the malloc bytes threshold.
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*
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* Pref: javascript.options.mem.high_water_mark
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* Default: TuningDefaults::MaxMallocBytes
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*/
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JSGC_MAX_MALLOC_BYTES = 1,
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/**
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* Maximum size of the generational GC nurseries.
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*
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* Pref: javascript.options.mem.nursery.max_kb
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* Default: JS::DefaultNurseryBytes
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*/
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JSGC_MAX_NURSERY_BYTES = 2,
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/** Amount of bytes allocated by the GC. */
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JSGC_BYTES = 3,
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/** Number of times GC has been invoked. Includes both major and minor GC. */
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JSGC_NUMBER = 4,
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/**
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* Select GC mode.
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*
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* See: JSGCMode in GCAPI.h
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* prefs: javascript.options.mem.gc_per_zone and
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* javascript.options.mem.gc_incremental.
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* Default: JSGC_MODE_INCREMENTAL
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*/
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JSGC_MODE = 6,
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/** Number of cached empty GC chunks. */
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JSGC_UNUSED_CHUNKS = 7,
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/** Total number of allocated GC chunks. */
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JSGC_TOTAL_CHUNKS = 8,
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/**
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* Max milliseconds to spend in an incremental GC slice.
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*
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* Pref: javascript.options.mem.gc_incremental_slice_ms
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* Default: DefaultTimeBudget.
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*/
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JSGC_SLICE_TIME_BUDGET = 9,
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/**
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* Maximum size the GC mark stack can grow to.
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*
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* Pref: none
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* Default: MarkStack::DefaultCapacity
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*/
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JSGC_MARK_STACK_LIMIT = 10,
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/**
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* GCs less than this far apart in time will be considered 'high-frequency
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* GCs'.
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*
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* See setGCLastBytes in jsgc.cpp.
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*
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* Pref: javascript.options.mem.gc_high_frequency_time_limit_ms
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* Default: HighFrequencyThreshold
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*/
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JSGC_HIGH_FREQUENCY_TIME_LIMIT = 11,
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/**
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* Start of dynamic heap growth.
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*
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* Pref: javascript.options.mem.gc_high_frequency_low_limit_mb
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* Default: HighFrequencyLowLimitBytes
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*/
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JSGC_HIGH_FREQUENCY_LOW_LIMIT = 12,
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/**
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* End of dynamic heap growth.
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*
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* Pref: javascript.options.mem.gc_high_frequency_high_limit_mb
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* Default: HighFrequencyHighLimitBytes
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*/
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JSGC_HIGH_FREQUENCY_HIGH_LIMIT = 13,
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/**
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* Upper bound of heap growth.
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*
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* Pref: javascript.options.mem.gc_high_frequency_heap_growth_max
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* Default: HighFrequencyHeapGrowthMax
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*/
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JSGC_HIGH_FREQUENCY_HEAP_GROWTH_MAX = 14,
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/**
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* Lower bound of heap growth.
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*
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* Pref: javascript.options.mem.gc_high_frequency_heap_growth_min
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* Default: HighFrequencyHeapGrowthMin
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*/
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JSGC_HIGH_FREQUENCY_HEAP_GROWTH_MIN = 15,
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/**
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* Heap growth for low frequency GCs.
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*
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* Pref: javascript.options.mem.gc_low_frequency_heap_growth
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* Default: LowFrequencyHeapGrowth
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*/
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JSGC_LOW_FREQUENCY_HEAP_GROWTH = 16,
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/**
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* If false, the heap growth factor is fixed at 3. If true, it is determined
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* based on whether GCs are high- or low- frequency.
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*
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* Pref: javascript.options.mem.gc_dynamic_heap_growth
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* Default: DynamicHeapGrowthEnabled
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*/
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JSGC_DYNAMIC_HEAP_GROWTH = 17,
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/**
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* If true, high-frequency GCs will use a longer mark slice.
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*
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* Pref: javascript.options.mem.gc_dynamic_mark_slice
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* Default: DynamicMarkSliceEnabled
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*/
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JSGC_DYNAMIC_MARK_SLICE = 18,
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/**
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* Lower limit after which we limit the heap growth.
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*
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* The base value used to compute zone->threshold.gcTriggerBytes(). When
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* usage.gcBytes() surpasses threshold.gcTriggerBytes() for a zone, the
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* zone may be scheduled for a GC, depending on the exact circumstances.
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*
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* Pref: javascript.options.mem.gc_allocation_threshold_mb
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* Default GCZoneAllocThresholdBase
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*/
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JSGC_ALLOCATION_THRESHOLD = 19,
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/**
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* We try to keep at least this many unused chunks in the free chunk pool at
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* all times, even after a shrinking GC.
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*
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* Pref: javascript.options.mem.gc_min_empty_chunk_count
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* Default: MinEmptyChunkCount
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*/
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JSGC_MIN_EMPTY_CHUNK_COUNT = 21,
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/**
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* We never keep more than this many unused chunks in the free chunk
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* pool.
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*
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* Pref: javascript.options.mem.gc_min_empty_chunk_count
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* Default: MinEmptyChunkCount
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*/
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JSGC_MAX_EMPTY_CHUNK_COUNT = 22,
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/**
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* Whether compacting GC is enabled.
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*
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* Pref: javascript.options.mem.gc_compacting
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* Default: CompactingEnabled
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*/
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JSGC_COMPACTING_ENABLED = 23,
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/**
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* Factor for triggering a GC based on JSGC_ALLOCATION_THRESHOLD
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*
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* Default: ZoneAllocThresholdFactorDefault
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* Pref: None
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*/
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JSGC_ALLOCATION_THRESHOLD_FACTOR = 25,
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/**
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* Factor for triggering a GC based on JSGC_ALLOCATION_THRESHOLD.
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* Used if another GC (in different zones) is already running.
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*
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* Default: ZoneAllocThresholdFactorAvoidInterruptDefault
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* Pref: None
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*/
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JSGC_ALLOCATION_THRESHOLD_FACTOR_AVOID_INTERRUPT = 26,
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/**
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* Attempt to run a minor GC in the idle time if the free space falls
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* below this threshold.
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*
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* Default: NurseryChunkUsableSize / 4
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* Pref: None
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*/
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JSGC_NURSERY_FREE_THRESHOLD_FOR_IDLE_COLLECTION = 27,
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} JSGCParamKey;
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/*
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* Generic trace operation that calls JS::TraceEdge on each traceable thing's
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* location reachable from data.
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*/
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typedef void
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(* JSTraceDataOp)(JSTracer* trc, void* data);
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typedef enum JSGCStatus {
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JSGC_BEGIN,
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JSGC_END
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} JSGCStatus;
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typedef void
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(* JSGCCallback)(JSContext* cx, JSGCStatus status, void* data);
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typedef void
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(* JSObjectsTenuredCallback)(JSContext* cx, void* data);
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typedef enum JSFinalizeStatus {
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/**
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* Called when preparing to sweep a group of zones, before anything has been
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* swept. The collector will not yield to the mutator before calling the
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* callback with JSFINALIZE_GROUP_START status.
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*/
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JSFINALIZE_GROUP_PREPARE,
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/**
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* Called after preparing to sweep a group of zones. Weak references to
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* unmarked things have been removed at this point, but no GC things have
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* been swept. The collector may yield to the mutator after this point.
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*/
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JSFINALIZE_GROUP_START,
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/**
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* Called after sweeping a group of zones. All dead GC things have been
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* swept at this point.
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*/
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JSFINALIZE_GROUP_END,
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/**
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* Called at the end of collection when everything has been swept.
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*/
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JSFINALIZE_COLLECTION_END
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} JSFinalizeStatus;
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typedef void
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(* JSFinalizeCallback)(JSFreeOp* fop, JSFinalizeStatus status, void* data);
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typedef void
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(* JSWeakPointerZonesCallback)(JSContext* cx, void* data);
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typedef void
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(* JSWeakPointerCompartmentCallback)(JSContext* cx, JS::Compartment* comp, void* data);
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/**
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* Finalizes external strings created by JS_NewExternalString. The finalizer
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* can be called off the main thread.
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*/
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struct JSStringFinalizer {
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void (*finalize)(const JSStringFinalizer* fin, char16_t* chars);
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};
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namespace JS {
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#define GCREASONS(D) \
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/* Reasons internal to the JS engine */ \
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D(API) \
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D(EAGER_ALLOC_TRIGGER) \
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D(DESTROY_RUNTIME) \
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D(ROOTS_REMOVED) \
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D(LAST_DITCH) \
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D(TOO_MUCH_MALLOC) \
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D(ALLOC_TRIGGER) \
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D(DEBUG_GC) \
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D(COMPARTMENT_REVIVED) \
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D(RESET) \
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D(OUT_OF_NURSERY) \
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D(EVICT_NURSERY) \
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D(DELAYED_ATOMS_GC) \
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D(SHARED_MEMORY_LIMIT) \
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D(IDLE_TIME_COLLECTION) \
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D(INCREMENTAL_TOO_SLOW) \
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D(ABORT_GC) \
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D(FULL_WHOLE_CELL_BUFFER) \
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D(FULL_GENERIC_BUFFER) \
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D(FULL_VALUE_BUFFER) \
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D(FULL_CELL_PTR_BUFFER) \
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D(FULL_SLOT_BUFFER) \
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D(FULL_SHAPE_BUFFER) \
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D(TOO_MUCH_WASM_MEMORY) \
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\
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/* These are reserved for future use. */ \
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D(RESERVED0) \
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D(RESERVED1) \
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D(RESERVED2) \
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D(RESERVED3) \
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D(RESERVED4) \
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D(RESERVED5) \
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D(RESERVED6) \
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D(RESERVED7) \
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D(RESERVED8) \
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\
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/* Reasons from Firefox */ \
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D(DOM_WINDOW_UTILS) \
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D(COMPONENT_UTILS) \
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D(MEM_PRESSURE) \
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D(CC_WAITING) \
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D(CC_FORCED) \
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D(LOAD_END) \
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D(POST_COMPARTMENT) \
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D(PAGE_HIDE) \
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D(NSJSCONTEXT_DESTROY) \
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D(SET_NEW_DOCUMENT) \
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D(SET_DOC_SHELL) \
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D(DOM_UTILS) \
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D(DOM_IPC) \
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D(DOM_WORKER) \
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D(INTER_SLICE_GC) \
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D(UNUSED1) \
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D(FULL_GC_TIMER) \
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D(SHUTDOWN_CC) \
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D(UNUSED2) \
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D(USER_INACTIVE) \
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D(XPCONNECT_SHUTDOWN) \
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D(DOCSHELL) \
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D(HTML_PARSER)
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namespace gcreason {
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/* GCReasons will end up looking like JSGC_MAYBEGC */
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enum Reason {
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#define MAKE_REASON(name) name,
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GCREASONS(MAKE_REASON)
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#undef MAKE_REASON
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NO_REASON,
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NUM_REASONS,
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/*
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* For telemetry, we want to keep a fixed max bucket size over time so we
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* don't have to switch histograms. 100 is conservative; as of this writing
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* there are 52. But the cost of extra buckets seems to be low while the
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* cost of switching histograms is high.
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*/
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NUM_TELEMETRY_REASONS = 100
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};
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/**
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* Get a statically allocated C string explaining the given GC reason.
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*/
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extern JS_PUBLIC_API(const char*)
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ExplainReason(JS::gcreason::Reason reason);
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} /* namespace gcreason */
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/*
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* Zone GC:
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*
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* SpiderMonkey's GC is capable of performing a collection on an arbitrary
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* subset of the zones in the system. This allows an embedding to minimize
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* collection time by only collecting zones that have run code recently,
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* ignoring the parts of the heap that are unlikely to have changed.
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*
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* When triggering a GC using one of the functions below, it is first necessary
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* to select the zones to be collected. To do this, you can call
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* PrepareZoneForGC on each zone, or you can call PrepareForFullGC to select
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* all zones. Failing to select any zone is an error.
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*/
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/**
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* Schedule the given zone to be collected as part of the next GC.
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*/
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extern JS_PUBLIC_API(void)
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PrepareZoneForGC(Zone* zone);
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/**
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* Schedule all zones to be collected in the next GC.
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*/
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extern JS_PUBLIC_API(void)
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PrepareForFullGC(JSContext* cx);
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/**
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* When performing an incremental GC, the zones that were selected for the
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* previous incremental slice must be selected in subsequent slices as well.
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* This function selects those slices automatically.
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*/
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extern JS_PUBLIC_API(void)
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PrepareForIncrementalGC(JSContext* cx);
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/**
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* Returns true if any zone in the system has been scheduled for GC with one of
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* the functions above or by the JS engine.
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*/
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extern JS_PUBLIC_API(bool)
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IsGCScheduled(JSContext* cx);
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/**
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* Undoes the effect of the Prepare methods above. The given zone will not be
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* collected in the next GC.
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*/
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extern JS_PUBLIC_API(void)
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SkipZoneForGC(Zone* zone);
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/*
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* Non-Incremental GC:
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*
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* The following functions perform a non-incremental GC.
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*/
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/**
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* Performs a non-incremental collection of all selected zones.
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*
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* If the gckind argument is GC_NORMAL, then some objects that are unreachable
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* from the program may still be alive afterwards because of internal
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* references; if GC_SHRINK is passed then caches and other temporary references
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* to objects will be cleared and all unreferenced objects will be removed from
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* the system.
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*/
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extern JS_PUBLIC_API(void)
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NonIncrementalGC(JSContext* cx, JSGCInvocationKind gckind, gcreason::Reason reason);
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/*
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* Incremental GC:
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*
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* Incremental GC divides the full mark-and-sweep collection into multiple
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* slices, allowing client JavaScript code to run between each slice. This
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* allows interactive apps to avoid long collection pauses. Incremental GC does
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* not make collection take less time, it merely spreads that time out so that
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* the pauses are less noticable.
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*
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* For a collection to be carried out incrementally the following conditions
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* must be met:
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* - The collection must be run by calling JS::IncrementalGC() rather than
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* JS_GC().
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* - The GC mode must have been set to JSGC_MODE_INCREMENTAL with
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* JS_SetGCParameter().
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*
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* Note: Even if incremental GC is enabled and working correctly,
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* non-incremental collections can still happen when low on memory.
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*/
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/**
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* Begin an incremental collection and perform one slice worth of work. When
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* this function returns, the collection may not be complete.
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* IncrementalGCSlice() must be called repeatedly until
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* !IsIncrementalGCInProgress(cx).
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*
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* Note: SpiderMonkey's GC is not realtime. Slices in practice may be longer or
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* shorter than the requested interval.
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*/
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extern JS_PUBLIC_API(void)
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StartIncrementalGC(JSContext* cx, JSGCInvocationKind gckind, gcreason::Reason reason,
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int64_t millis = 0);
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|
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/**
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* Perform a slice of an ongoing incremental collection. When this function
|
|
* returns, the collection may not be complete. It must be called repeatedly
|
|
* until !IsIncrementalGCInProgress(cx).
|
|
*
|
|
* Note: SpiderMonkey's GC is not realtime. Slices in practice may be longer or
|
|
* shorter than the requested interval.
|
|
*/
|
|
extern JS_PUBLIC_API(void)
|
|
IncrementalGCSlice(JSContext* cx, gcreason::Reason reason, int64_t millis = 0);
|
|
|
|
/**
|
|
* If IsIncrementalGCInProgress(cx), this call finishes the ongoing collection
|
|
* by performing an arbitrarily long slice. If !IsIncrementalGCInProgress(cx),
|
|
* this is equivalent to NonIncrementalGC. When this function returns,
|
|
* IsIncrementalGCInProgress(cx) will always be false.
|
|
*/
|
|
extern JS_PUBLIC_API(void)
|
|
FinishIncrementalGC(JSContext* cx, gcreason::Reason reason);
|
|
|
|
/**
|
|
* If IsIncrementalGCInProgress(cx), this call aborts the ongoing collection and
|
|
* performs whatever work needs to be done to return the collector to its idle
|
|
* state. This may take an arbitrarily long time. When this function returns,
|
|
* IsIncrementalGCInProgress(cx) will always be false.
|
|
*/
|
|
extern JS_PUBLIC_API(void)
|
|
AbortIncrementalGC(JSContext* cx);
|
|
|
|
namespace dbg {
|
|
|
|
// The `JS::dbg::GarbageCollectionEvent` class is essentially a view of the
|
|
// `js::gcstats::Statistics` data without the uber implementation-specific bits.
|
|
// It should generally be palatable for web developers.
|
|
class GarbageCollectionEvent
|
|
{
|
|
// The major GC number of the GC cycle this data pertains to.
|
|
uint64_t majorGCNumber_;
|
|
|
|
// Reference to a non-owned, statically allocated C string. This is a very
|
|
// short reason explaining why a GC was triggered.
|
|
const char* reason;
|
|
|
|
// Reference to a nullable, non-owned, statically allocated C string. If the
|
|
// collection was forced to be non-incremental, this is a short reason of
|
|
// why the GC could not perform an incremental collection.
|
|
const char* nonincrementalReason;
|
|
|
|
// Represents a single slice of a possibly multi-slice incremental garbage
|
|
// collection.
|
|
struct Collection {
|
|
mozilla::TimeStamp startTimestamp;
|
|
mozilla::TimeStamp endTimestamp;
|
|
};
|
|
|
|
// The set of garbage collection slices that made up this GC cycle.
|
|
mozilla::Vector<Collection> collections;
|
|
|
|
GarbageCollectionEvent(const GarbageCollectionEvent& rhs) = delete;
|
|
GarbageCollectionEvent& operator=(const GarbageCollectionEvent& rhs) = delete;
|
|
|
|
public:
|
|
explicit GarbageCollectionEvent(uint64_t majorGCNum)
|
|
: majorGCNumber_(majorGCNum)
|
|
, reason(nullptr)
|
|
, nonincrementalReason(nullptr)
|
|
, collections()
|
|
{ }
|
|
|
|
using Ptr = js::UniquePtr<GarbageCollectionEvent>;
|
|
static Ptr Create(JSRuntime* rt, ::js::gcstats::Statistics& stats, uint64_t majorGCNumber);
|
|
|
|
JSObject* toJSObject(JSContext* cx) const;
|
|
|
|
uint64_t majorGCNumber() const { return majorGCNumber_; }
|
|
};
|
|
|
|
} // namespace dbg
|
|
|
|
enum GCProgress {
|
|
/*
|
|
* During GC, the GC is bracketed by GC_CYCLE_BEGIN/END callbacks. Each
|
|
* slice between those (whether an incremental or the sole non-incremental
|
|
* slice) is bracketed by GC_SLICE_BEGIN/GC_SLICE_END.
|
|
*/
|
|
|
|
GC_CYCLE_BEGIN,
|
|
GC_SLICE_BEGIN,
|
|
GC_SLICE_END,
|
|
GC_CYCLE_END
|
|
};
|
|
|
|
struct JS_PUBLIC_API(GCDescription) {
|
|
bool isZone_;
|
|
bool isComplete_;
|
|
JSGCInvocationKind invocationKind_;
|
|
gcreason::Reason reason_;
|
|
|
|
GCDescription(bool isZone, bool isComplete, JSGCInvocationKind kind, gcreason::Reason reason)
|
|
: isZone_(isZone), isComplete_(isComplete), invocationKind_(kind), reason_(reason) {}
|
|
|
|
char16_t* formatSliceMessage(JSContext* cx) const;
|
|
char16_t* formatSummaryMessage(JSContext* cx) const;
|
|
char16_t* formatJSON(JSContext* cx, uint64_t timestamp) const;
|
|
|
|
mozilla::TimeStamp startTime(JSContext* cx) const;
|
|
mozilla::TimeStamp endTime(JSContext* cx) const;
|
|
mozilla::TimeStamp lastSliceStart(JSContext* cx) const;
|
|
mozilla::TimeStamp lastSliceEnd(JSContext* cx) const;
|
|
|
|
JS::UniqueChars sliceToJSON(JSContext* cx) const;
|
|
JS::UniqueChars summaryToJSON(JSContext* cx) const;
|
|
|
|
JS::dbg::GarbageCollectionEvent::Ptr toGCEvent(JSContext* cx) const;
|
|
};
|
|
|
|
extern JS_PUBLIC_API(UniqueChars)
|
|
MinorGcToJSON(JSContext* cx);
|
|
|
|
typedef void
|
|
(* GCSliceCallback)(JSContext* cx, GCProgress progress, const GCDescription& desc);
|
|
|
|
/**
|
|
* The GC slice callback is called at the beginning and end of each slice. This
|
|
* callback may be used for GC notifications as well as to perform additional
|
|
* marking.
|
|
*/
|
|
extern JS_PUBLIC_API(GCSliceCallback)
|
|
SetGCSliceCallback(JSContext* cx, GCSliceCallback callback);
|
|
|
|
/**
|
|
* Describes the progress of an observed nursery collection.
|
|
*/
|
|
enum class GCNurseryProgress {
|
|
/**
|
|
* The nursery collection is starting.
|
|
*/
|
|
GC_NURSERY_COLLECTION_START,
|
|
/**
|
|
* The nursery collection is ending.
|
|
*/
|
|
GC_NURSERY_COLLECTION_END
|
|
};
|
|
|
|
/**
|
|
* A nursery collection callback receives the progress of the nursery collection
|
|
* and the reason for the collection.
|
|
*/
|
|
using GCNurseryCollectionCallback = void(*)(JSContext* cx, GCNurseryProgress progress,
|
|
gcreason::Reason reason);
|
|
|
|
/**
|
|
* Set the nursery collection callback for the given runtime. When set, it will
|
|
* be called at the start and end of every nursery collection.
|
|
*/
|
|
extern JS_PUBLIC_API(GCNurseryCollectionCallback)
|
|
SetGCNurseryCollectionCallback(JSContext* cx, GCNurseryCollectionCallback callback);
|
|
|
|
typedef void
|
|
(* DoCycleCollectionCallback)(JSContext* cx);
|
|
|
|
/**
|
|
* The purge gray callback is called after any COMPARTMENT_REVIVED GC in which
|
|
* the majority of compartments have been marked gray.
|
|
*/
|
|
extern JS_PUBLIC_API(DoCycleCollectionCallback)
|
|
SetDoCycleCollectionCallback(JSContext* cx, DoCycleCollectionCallback callback);
|
|
|
|
/**
|
|
* Incremental GC defaults to enabled, but may be disabled for testing or in
|
|
* embeddings that have not yet implemented barriers on their native classes.
|
|
* There is not currently a way to re-enable incremental GC once it has been
|
|
* disabled on the runtime.
|
|
*/
|
|
extern JS_PUBLIC_API(void)
|
|
DisableIncrementalGC(JSContext* cx);
|
|
|
|
/**
|
|
* Returns true if incremental GC is enabled. Simply having incremental GC
|
|
* enabled is not sufficient to ensure incremental collections are happening.
|
|
* See the comment "Incremental GC" above for reasons why incremental GC may be
|
|
* suppressed. Inspection of the "nonincremental reason" field of the
|
|
* GCDescription returned by GCSliceCallback may help narrow down the cause if
|
|
* collections are not happening incrementally when expected.
|
|
*/
|
|
extern JS_PUBLIC_API(bool)
|
|
IsIncrementalGCEnabled(JSContext* cx);
|
|
|
|
/**
|
|
* Returns true while an incremental GC is ongoing, both when actively
|
|
* collecting and between slices.
|
|
*/
|
|
extern JS_PUBLIC_API(bool)
|
|
IsIncrementalGCInProgress(JSContext* cx);
|
|
|
|
/**
|
|
* Returns true while an incremental GC is ongoing, both when actively
|
|
* collecting and between slices.
|
|
*/
|
|
extern JS_PUBLIC_API(bool)
|
|
IsIncrementalGCInProgress(JSRuntime* rt);
|
|
|
|
/**
|
|
* Returns true if the most recent GC ran incrementally.
|
|
*/
|
|
extern JS_PUBLIC_API(bool)
|
|
WasIncrementalGC(JSRuntime* rt);
|
|
|
|
/*
|
|
* Generational GC:
|
|
*
|
|
* Note: Generational GC is not yet enabled by default. The following class
|
|
* is non-functional unless SpiderMonkey was configured with
|
|
* --enable-gcgenerational.
|
|
*/
|
|
|
|
/** Ensure that generational GC is disabled within some scope. */
|
|
class JS_PUBLIC_API(AutoDisableGenerationalGC)
|
|
{
|
|
JSContext* cx;
|
|
|
|
public:
|
|
explicit AutoDisableGenerationalGC(JSContext* cx);
|
|
~AutoDisableGenerationalGC();
|
|
};
|
|
|
|
/**
|
|
* Returns true if generational allocation and collection is currently enabled
|
|
* on the given runtime.
|
|
*/
|
|
extern JS_PUBLIC_API(bool)
|
|
IsGenerationalGCEnabled(JSRuntime* rt);
|
|
|
|
/**
|
|
* Returns the GC's "number". This does not correspond directly to the number
|
|
* of GCs that have been run, but is guaranteed to be monotonically increasing
|
|
* with GC activity.
|
|
*/
|
|
extern JS_PUBLIC_API(size_t)
|
|
GetGCNumber();
|
|
|
|
/**
|
|
* Pass a subclass of this "abstract" class to callees to require that they
|
|
* never GC. Subclasses can use assertions or the hazard analysis to ensure no
|
|
* GC happens.
|
|
*/
|
|
class JS_PUBLIC_API(AutoRequireNoGC)
|
|
{
|
|
protected:
|
|
AutoRequireNoGC() {}
|
|
~AutoRequireNoGC() {}
|
|
};
|
|
|
|
/**
|
|
* Diagnostic assert (see MOZ_DIAGNOSTIC_ASSERT) that GC cannot occur while this
|
|
* class is live. This class does not disable the static rooting hazard
|
|
* analysis.
|
|
*
|
|
* This works by entering a GC unsafe region, which is checked on allocation and
|
|
* on GC.
|
|
*/
|
|
class JS_PUBLIC_API(AutoAssertNoGC) : public AutoRequireNoGC
|
|
{
|
|
#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
|
|
JSContext* cx_;
|
|
|
|
public:
|
|
// This gets the context from TLS if it is not passed in.
|
|
explicit AutoAssertNoGC(JSContext* cx = nullptr);
|
|
~AutoAssertNoGC();
|
|
#else
|
|
public:
|
|
explicit AutoAssertNoGC(JSContext* cx = nullptr) {}
|
|
~AutoAssertNoGC() {}
|
|
#endif
|
|
};
|
|
|
|
/**
|
|
* Disable the static rooting hazard analysis in the live region and assert in
|
|
* debug builds if any allocation that could potentially trigger a GC occurs
|
|
* while this guard object is live. This is most useful to help the exact
|
|
* rooting hazard analysis in complex regions, since it cannot understand
|
|
* dataflow.
|
|
*
|
|
* Note: GC behavior is unpredictable even when deterministic and is generally
|
|
* non-deterministic in practice. The fact that this guard has not
|
|
* asserted is not a guarantee that a GC cannot happen in the guarded
|
|
* region. As a rule, anyone performing a GC unsafe action should
|
|
* understand the GC properties of all code in that region and ensure
|
|
* that the hazard analysis is correct for that code, rather than relying
|
|
* on this class.
|
|
*/
|
|
#ifdef DEBUG
|
|
class JS_PUBLIC_API(AutoSuppressGCAnalysis) : public AutoAssertNoGC
|
|
{
|
|
public:
|
|
explicit AutoSuppressGCAnalysis(JSContext* cx = nullptr) : AutoAssertNoGC(cx) {}
|
|
} JS_HAZ_GC_SUPPRESSED;
|
|
#else
|
|
class JS_PUBLIC_API(AutoSuppressGCAnalysis) : public AutoRequireNoGC
|
|
{
|
|
public:
|
|
explicit AutoSuppressGCAnalysis(JSContext* cx = nullptr) {}
|
|
} JS_HAZ_GC_SUPPRESSED;
|
|
#endif
|
|
|
|
/**
|
|
* Assert that code is only ever called from a GC callback, disable the static
|
|
* rooting hazard analysis and assert if any allocation that could potentially
|
|
* trigger a GC occurs while this guard object is live.
|
|
*
|
|
* This is useful to make the static analysis ignore code that runs in GC
|
|
* callbacks.
|
|
*/
|
|
class JS_PUBLIC_API(AutoAssertGCCallback) : public AutoSuppressGCAnalysis
|
|
{
|
|
public:
|
|
#ifdef DEBUG
|
|
AutoAssertGCCallback();
|
|
#else
|
|
AutoAssertGCCallback() {}
|
|
#endif
|
|
};
|
|
|
|
/**
|
|
* Place AutoCheckCannotGC in scopes that you believe can never GC. These
|
|
* annotations will be verified both dynamically via AutoAssertNoGC, and
|
|
* statically with the rooting hazard analysis (implemented by making the
|
|
* analysis consider AutoCheckCannotGC to be a GC pointer, and therefore
|
|
* complain if it is live across a GC call.) It is useful when dealing with
|
|
* internal pointers to GC things where the GC thing itself may not be present
|
|
* for the static analysis: e.g. acquiring inline chars from a JSString* on the
|
|
* heap.
|
|
*
|
|
* We only do the assertion checking in DEBUG builds.
|
|
*/
|
|
#ifdef DEBUG
|
|
class JS_PUBLIC_API(AutoCheckCannotGC) : public AutoAssertNoGC
|
|
{
|
|
public:
|
|
explicit AutoCheckCannotGC(JSContext* cx = nullptr) : AutoAssertNoGC(cx) {}
|
|
} JS_HAZ_GC_INVALIDATED;
|
|
#else
|
|
class JS_PUBLIC_API(AutoCheckCannotGC) : public AutoRequireNoGC
|
|
{
|
|
public:
|
|
explicit AutoCheckCannotGC(JSContext* cx = nullptr) {}
|
|
} JS_HAZ_GC_INVALIDATED;
|
|
#endif
|
|
|
|
/*
|
|
* Internal to Firefox.
|
|
*/
|
|
extern JS_FRIEND_API(void)
|
|
NotifyGCRootsRemoved(JSContext* cx);
|
|
|
|
} /* namespace JS */
|
|
|
|
/**
|
|
* Register externally maintained GC roots.
|
|
*
|
|
* traceOp: the trace operation. For each root the implementation should call
|
|
* JS::TraceEdge whenever the root contains a traceable thing.
|
|
* data: the data argument to pass to each invocation of traceOp.
|
|
*/
|
|
extern JS_PUBLIC_API(bool)
|
|
JS_AddExtraGCRootsTracer(JSContext* cx, JSTraceDataOp traceOp, void* data);
|
|
|
|
/** Undo a call to JS_AddExtraGCRootsTracer. */
|
|
extern JS_PUBLIC_API(void)
|
|
JS_RemoveExtraGCRootsTracer(JSContext* cx, JSTraceDataOp traceOp, void* data);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_GC(JSContext* cx);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_MaybeGC(JSContext* cx);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_SetGCCallback(JSContext* cx, JSGCCallback cb, void* data);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_SetObjectsTenuredCallback(JSContext* cx, JSObjectsTenuredCallback cb,
|
|
void* data);
|
|
|
|
extern JS_PUBLIC_API(bool)
|
|
JS_AddFinalizeCallback(JSContext* cx, JSFinalizeCallback cb, void* data);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_RemoveFinalizeCallback(JSContext* cx, JSFinalizeCallback cb);
|
|
|
|
/*
|
|
* Weak pointers and garbage collection
|
|
*
|
|
* Weak pointers are by their nature not marked as part of garbage collection,
|
|
* but they may need to be updated in two cases after a GC:
|
|
*
|
|
* 1) Their referent was found not to be live and is about to be finalized
|
|
* 2) Their referent has been moved by a compacting GC
|
|
*
|
|
* To handle this, any part of the system that maintain weak pointers to
|
|
* JavaScript GC things must register a callback with
|
|
* JS_(Add,Remove)WeakPointer{ZoneGroup,Compartment}Callback(). This callback
|
|
* must then call JS_UpdateWeakPointerAfterGC() on all weak pointers it knows
|
|
* about.
|
|
*
|
|
* Since sweeping is incremental, we have several callbacks to avoid repeatedly
|
|
* having to visit all embedder structures. The WeakPointerZonesCallback is
|
|
* called once for each strongly connected group of zones, whereas the
|
|
* WeakPointerCompartmentCallback is called once for each compartment that is
|
|
* visited while sweeping. Structures that cannot contain references in more
|
|
* than one compartment should sweep the relevant per-compartment structures
|
|
* using the latter callback to minimizer per-slice overhead.
|
|
*
|
|
* The argument to JS_UpdateWeakPointerAfterGC() is an in-out param. If the
|
|
* referent is about to be finalized the pointer will be set to null. If the
|
|
* referent has been moved then the pointer will be updated to point to the new
|
|
* location.
|
|
*
|
|
* Callers of this method are responsible for updating any state that is
|
|
* dependent on the object's address. For example, if the object's address is
|
|
* used as a key in a hashtable, then the object must be removed and
|
|
* re-inserted with the correct hash.
|
|
*/
|
|
|
|
extern JS_PUBLIC_API(bool)
|
|
JS_AddWeakPointerZonesCallback(JSContext* cx, JSWeakPointerZonesCallback cb, void* data);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_RemoveWeakPointerZonesCallback(JSContext* cx, JSWeakPointerZonesCallback cb);
|
|
|
|
extern JS_PUBLIC_API(bool)
|
|
JS_AddWeakPointerCompartmentCallback(JSContext* cx, JSWeakPointerCompartmentCallback cb,
|
|
void* data);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_RemoveWeakPointerCompartmentCallback(JSContext* cx, JSWeakPointerCompartmentCallback cb);
|
|
|
|
namespace JS {
|
|
template <typename T> class Heap;
|
|
}
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_UpdateWeakPointerAfterGC(JS::Heap<JSObject*>* objp);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_UpdateWeakPointerAfterGCUnbarriered(JSObject** objp);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_SetGCParameter(JSContext* cx, JSGCParamKey key, uint32_t value);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_ResetGCParameter(JSContext* cx, JSGCParamKey key);
|
|
|
|
extern JS_PUBLIC_API(uint32_t)
|
|
JS_GetGCParameter(JSContext* cx, JSGCParamKey key);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_SetGCParametersBasedOnAvailableMemory(JSContext* cx, uint32_t availMem);
|
|
|
|
/**
|
|
* Create a new JSString whose chars member refers to external memory, i.e.,
|
|
* memory requiring application-specific finalization.
|
|
*/
|
|
extern JS_PUBLIC_API(JSString*)
|
|
JS_NewExternalString(JSContext* cx, const char16_t* chars, size_t length,
|
|
const JSStringFinalizer* fin);
|
|
|
|
/**
|
|
* Create a new JSString whose chars member may refer to external memory.
|
|
* If a new external string is allocated, |*allocatedExternal| is set to true.
|
|
* Otherwise the returned string is either not an external string or an
|
|
* external string allocated by a previous call and |*allocatedExternal| is set
|
|
* to false. If |*allocatedExternal| is false, |fin| won't be called.
|
|
*/
|
|
extern JS_PUBLIC_API(JSString*)
|
|
JS_NewMaybeExternalString(JSContext* cx, const char16_t* chars, size_t length,
|
|
const JSStringFinalizer* fin, bool* allocatedExternal);
|
|
|
|
/**
|
|
* Return whether 'str' was created with JS_NewExternalString or
|
|
* JS_NewExternalStringWithClosure.
|
|
*/
|
|
extern JS_PUBLIC_API(bool)
|
|
JS_IsExternalString(JSString* str);
|
|
|
|
/**
|
|
* Return the 'fin' arg passed to JS_NewExternalString.
|
|
*/
|
|
extern JS_PUBLIC_API(const JSStringFinalizer*)
|
|
JS_GetExternalStringFinalizer(JSString* str);
|
|
|
|
namespace JS {
|
|
|
|
extern JS_PUBLIC_API(bool)
|
|
IsIdleGCTaskNeeded(JSRuntime* rt);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
RunIdleTimeGCTask(JSRuntime* rt);
|
|
|
|
} // namespace JS
|
|
|
|
namespace js {
|
|
namespace gc {
|
|
|
|
/**
|
|
* Create an object providing access to the garbage collector's internal notion
|
|
* of the current state of memory (both GC heap memory and GCthing-controlled
|
|
* malloc memory.
|
|
*/
|
|
extern JS_PUBLIC_API(JSObject*)
|
|
NewMemoryInfoObject(JSContext* cx);
|
|
|
|
} /* namespace gc */
|
|
} /* namespace js */
|
|
|
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#endif /* js_GCAPI_h */
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