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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
/* Shadow definition of |JS::Zone| innards. Do not use this directly! */
#ifndef js_shadow_Zone_h
#define js_shadow_Zone_h
#include "mozilla/Assertions.h" // MOZ_ASSERT
#include "mozilla/Atomics.h"
#include <stdint.h> // uint8_t, uint32_t
#include "jspubtd.h" // js::CurrentThreadCanAccessRuntime
#include "jstypes.h" // js::Bit
struct JS_PUBLIC_API JSRuntime;
class JS_PUBLIC_API JSTracer;
namespace JS {
namespace shadow {
struct Zone {
enum GCState : uint32_t {
NoGC = 0,
Prepare,
MarkBlackOnly,
MarkBlackAndGray,
Sweep,
Finished,
Compact,
VerifyPreBarriers,
Limit
};
using BarrierState = mozilla::Atomic<uint32_t, mozilla::Relaxed>;
enum Kind : uint8_t { NormalZone, AtomsZone, SystemZone };
protected:
JSRuntime* const runtime_;
JSTracer* const barrierTracer_; // A pointer to the JSRuntime's |gcMarker|.
BarrierState needsIncrementalBarrier_;
GCState gcState_ = NoGC;
const Kind kind_;
Zone(JSRuntime* runtime, JSTracer* barrierTracerArg, Kind kind)
: runtime_(runtime), barrierTracer_(barrierTracerArg), kind_(kind) {
MOZ_ASSERT(!needsIncrementalBarrier());
}
public:
bool needsIncrementalBarrier() const { return needsIncrementalBarrier_; }
JSTracer* barrierTracer() {
MOZ_ASSERT(needsIncrementalBarrier_);
MOZ_ASSERT(js::CurrentThreadCanAccessRuntime(runtime_));
return barrierTracer_;
}
JSRuntime* runtimeFromMainThread() const {
MOZ_ASSERT(js::CurrentThreadCanAccessRuntime(runtime_));
return runtime_;
}
// Note: Unrestricted access to the zone's runtime from an arbitrary
// thread can easily lead to races. Use this method very carefully.
JSRuntime* runtimeFromAnyThread() const { return runtime_; }
GCState gcState() const { return GCState(uint32_t(gcState_)); }
static constexpr uint32_t gcStateMask(GCState state) {
static_assert(uint32_t(Limit) < 32);
return js::Bit(state);
}
bool hasAnyGCState(uint32_t stateMask) const {
return js::Bit(gcState_) & stateMask;
}
bool wasGCStarted() const { return gcState() != NoGC; }
bool isGCPreparing() const { return gcState() == Prepare; }
bool isGCMarkingBlackOnly() const { return gcState() == MarkBlackOnly; }
bool isGCMarkingBlackAndGray() const { return gcState() == MarkBlackAndGray; }
bool isGCSweeping() const { return gcState() == Sweep; }
bool isGCFinished() const { return gcState() == Finished; }
bool isGCCompacting() const { return gcState() == Compact; }
bool isGCMarking() const {
return hasAnyGCState(gcStateMask(MarkBlackOnly) |
gcStateMask(MarkBlackAndGray));
}
bool isGCMarkingOrSweeping() const {
return hasAnyGCState(gcStateMask(MarkBlackOnly) |
gcStateMask(MarkBlackAndGray) | gcStateMask(Sweep));
}
bool isGCMarkingOrVerifyingPreBarriers() const {
return hasAnyGCState(gcStateMask(MarkBlackOnly) |
gcStateMask(MarkBlackAndGray) |
gcStateMask(VerifyPreBarriers));
}
bool isGCSweepingOrCompacting() const {
return hasAnyGCState(gcStateMask(Sweep) | gcStateMask(Compact));
}
bool isVerifyingPreBarriers() const { return gcState() == VerifyPreBarriers; }
bool isAtomsZone() const { return kind_ == AtomsZone; }
bool isSystemZone() const { return kind_ == SystemZone; }
static shadow::Zone* from(JS::Zone* zone) {
return reinterpret_cast<shadow::Zone*>(zone);
}
static const shadow::Zone* from(const JS::Zone* zone) {
return reinterpret_cast<const shadow::Zone*>(zone);
}
};
} // namespace shadow
} // namespace JS
#endif // js_shadow_Zone_h