зеркало из https://github.com/mozilla/gecko-dev.git
352 строки
10 KiB
C++
352 строки
10 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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#ifndef js_GCAPI_h
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#define js_GCAPI_h
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#include "mozilla/NullPtr.h"
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#include "js/HeapAPI.h"
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#include "js/RootingAPI.h"
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#include "js/Value.h"
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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(MAYBEGC) \
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D(DESTROY_RUNTIME) \
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D(DESTROY_CONTEXT) \
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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(TRANSPLANT) \
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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(FULL_STORE_BUFFER) \
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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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D(RESERVED9) \
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D(RESERVED10) \
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D(RESERVED11) \
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D(RESERVED12) \
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D(RESERVED13) \
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D(RESERVED14) \
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D(RESERVED15) \
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D(RESERVED16) \
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D(RESERVED17) \
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D(RESERVED18) \
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D(RESERVED19) \
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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(REFRESH_FRAME) \
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D(FULL_GC_TIMER) \
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D(SHUTDOWN_CC) \
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D(FINISH_LARGE_EVALUTE)
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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 26. 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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} /* namespace gcreason */
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extern JS_FRIEND_API(void)
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PrepareZoneForGC(Zone *zone);
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extern JS_FRIEND_API(void)
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PrepareForFullGC(JSRuntime *rt);
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extern JS_FRIEND_API(void)
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PrepareForIncrementalGC(JSRuntime *rt);
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extern JS_FRIEND_API(bool)
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IsGCScheduled(JSRuntime *rt);
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extern JS_FRIEND_API(void)
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SkipZoneForGC(Zone *zone);
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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 compartments to be collected. To do this, you can call
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* PrepareZoneForGC on each compartment, or you can call PrepareForFullGC
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* to select all compartments. Failing to select any compartment is an error.
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*/
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extern JS_FRIEND_API(void)
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GCForReason(JSRuntime *rt, gcreason::Reason reason);
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extern JS_FRIEND_API(void)
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ShrinkingGC(JSRuntime *rt, gcreason::Reason reason);
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extern JS_FRIEND_API(void)
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ShrinkGCBuffers(JSRuntime *rt);
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extern JS_FRIEND_API(void)
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IncrementalGC(JSRuntime *rt, gcreason::Reason reason, int64_t millis = 0);
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extern JS_FRIEND_API(void)
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FinishIncrementalGC(JSRuntime *rt, gcreason::Reason reason);
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enum GCProgress {
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/*
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* During non-incremental GC, the GC is bracketed by JSGC_CYCLE_BEGIN/END
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* callbacks. During an incremental GC, the sequence of callbacks is as
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* follows:
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* JSGC_CYCLE_BEGIN, JSGC_SLICE_END (first slice)
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* JSGC_SLICE_BEGIN, JSGC_SLICE_END (second slice)
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* ...
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* JSGC_SLICE_BEGIN, JSGC_CYCLE_END (last slice)
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*/
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GC_CYCLE_BEGIN,
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GC_SLICE_BEGIN,
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GC_SLICE_END,
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GC_CYCLE_END
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};
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struct JS_FRIEND_API(GCDescription) {
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bool isCompartment_;
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GCDescription(bool isCompartment)
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: isCompartment_(isCompartment) {}
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jschar *formatMessage(JSRuntime *rt) const;
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jschar *formatJSON(JSRuntime *rt, uint64_t timestamp) const;
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};
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typedef void
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(* GCSliceCallback)(JSRuntime *rt, GCProgress progress, const GCDescription &desc);
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extern JS_FRIEND_API(GCSliceCallback)
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SetGCSliceCallback(JSRuntime *rt, GCSliceCallback callback);
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/*
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* Signals a good place to do an incremental slice, because the browser is
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* drawing a frame.
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*/
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extern JS_FRIEND_API(void)
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NotifyDidPaint(JSRuntime *rt);
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extern JS_FRIEND_API(bool)
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IsIncrementalGCEnabled(JSRuntime *rt);
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JS_FRIEND_API(bool)
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IsIncrementalGCInProgress(JSRuntime *rt);
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extern JS_FRIEND_API(void)
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DisableIncrementalGC(JSRuntime *rt);
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extern JS_FRIEND_API(void)
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DisableGenerationalGC(JSRuntime *rt);
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extern JS_FRIEND_API(void)
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EnableGenerationalGC(JSRuntime *rt);
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extern JS_FRIEND_API(bool)
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IsGenerationalGCEnabled(JSRuntime *rt);
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extern JS_FRIEND_API(bool)
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IsIncrementalBarrierNeeded(JSRuntime *rt);
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extern JS_FRIEND_API(bool)
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IsIncrementalBarrierNeeded(JSContext *cx);
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extern JS_FRIEND_API(void)
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IncrementalReferenceBarrier(void *ptr, JSGCTraceKind kind);
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extern JS_FRIEND_API(void)
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IncrementalValueBarrier(const Value &v);
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extern JS_FRIEND_API(void)
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IncrementalObjectBarrier(JSObject *obj);
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extern JS_FRIEND_API(void)
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PokeGC(JSRuntime *rt);
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/* Was the most recent GC run incrementally? */
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extern JS_FRIEND_API(bool)
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WasIncrementalGC(JSRuntime *rt);
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extern JS_FRIEND_API(size_t)
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GetGCNumber();
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class JS_PUBLIC_API(AutoAssertNoGC)
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{
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#ifdef JS_DEBUG
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JSRuntime *runtime;
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size_t gcNumber;
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public:
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AutoAssertNoGC();
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AutoAssertNoGC(JSRuntime *rt);
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~AutoAssertNoGC();
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#else
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public:
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/* Prevent unreferenced local warnings in opt builds. */
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AutoAssertNoGC() {}
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AutoAssertNoGC(JSRuntime *) {}
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#endif
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};
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class JS_PUBLIC_API(ObjectPtr)
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{
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Heap<JSObject *> value;
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public:
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ObjectPtr() : value(nullptr) {}
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ObjectPtr(JSObject *obj) : value(obj) {}
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/* Always call finalize before the destructor. */
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~ObjectPtr() { JS_ASSERT(!value); }
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void finalize(JSRuntime *rt) {
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if (IsIncrementalBarrierNeeded(rt))
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IncrementalObjectBarrier(value);
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value = nullptr;
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}
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void init(JSObject *obj) { value = obj; }
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JSObject *get() const { return value; }
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void writeBarrierPre(JSRuntime *rt) {
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IncrementalObjectBarrier(value);
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}
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bool isAboutToBeFinalized();
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ObjectPtr &operator=(JSObject *obj) {
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IncrementalObjectBarrier(value);
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value = obj;
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return *this;
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}
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void trace(JSTracer *trc, const char *name);
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JSObject &operator*() const { return *value; }
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JSObject *operator->() const { return value; }
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operator JSObject *() const { return value; }
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};
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/*
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* Unsets the gray bit for anything reachable from |thing|. |kind| should not be
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* JSTRACE_SHAPE. |thing| should be non-null.
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*/
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extern JS_FRIEND_API(bool)
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UnmarkGrayGCThingRecursively(void *thing, JSGCTraceKind kind);
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/*
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* This should be called when an object that is marked gray is exposed to the JS
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* engine (by handing it to running JS code or writing it into live JS
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* data). During incremental GC, since the gray bits haven't been computed yet,
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* we conservatively mark the object black.
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*/
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static JS_ALWAYS_INLINE void
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ExposeGCThingToActiveJS(void *thing, JSGCTraceKind kind)
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{
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JS_ASSERT(kind != JSTRACE_SHAPE);
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shadow::Runtime *rt = js::gc::GetGCThingRuntime(thing);
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#ifdef JSGC_GENERATIONAL
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/*
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* GC things residing in the nursery cannot be gray: they have no mark bits.
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* All live objects in the nursery are moved to tenured at the beginning of
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* each GC slice, so the gray marker never sees nursery things.
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*/
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if (js::gc::IsInsideNursery(rt, thing))
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return;
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#endif
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if (IsIncrementalBarrierNeededOnGCThing(rt, thing, kind))
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IncrementalReferenceBarrier(thing, kind);
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else if (GCThingIsMarkedGray(thing))
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UnmarkGrayGCThingRecursively(thing, kind);
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}
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static JS_ALWAYS_INLINE void
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ExposeValueToActiveJS(const Value &v)
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{
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if (v.isMarkable())
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ExposeGCThingToActiveJS(v.toGCThing(), v.gcKind());
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}
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static JS_ALWAYS_INLINE void
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ExposeObjectToActiveJS(JSObject *obj)
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{
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ExposeGCThingToActiveJS(obj, JSTRACE_OBJECT);
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}
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/*
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* If a GC is currently marking, mark the object black.
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*/
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static JS_ALWAYS_INLINE void
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MarkGCThingAsLive(JSRuntime *rt_, void *thing, JSGCTraceKind kind)
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{
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shadow::Runtime *rt = shadow::Runtime::asShadowRuntime(rt_);
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#ifdef JSGC_GENERATIONAL
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/*
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* Any object in the nursery will not be freed during any GC running at that time.
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*/
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if (js::gc::IsInsideNursery(rt, thing))
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return;
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#endif
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if (IsIncrementalBarrierNeededOnGCThing(rt, thing, kind))
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IncrementalReferenceBarrier(thing, kind);
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}
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static JS_ALWAYS_INLINE void
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MarkStringAsLive(Zone *zone, JSString *string)
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{
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JSRuntime *rt = JS::shadow::Zone::asShadowZone(zone)->runtimeFromMainThread();
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MarkGCThingAsLive(rt, string, JSTRACE_STRING);
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}
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} /* namespace JS */
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#endif /* js_GCAPI_h */
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