1 files changed, 126 insertions, 0 deletions
diff --git a/js/public/shadow/Zone.h b/js/public/shadow/Zone.h
new file mode 100644
index 0000000000..02cd57a14b
--- /dev/null
+++ b/js/public/shadow/Zone.h
@@ -0,0 +1,126 @@
+/* -*- 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/. */
+
+/* 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