1 files changed, 156 insertions, 0 deletions
diff --git a/js/src/vm/RealmFuses.h b/js/src/vm/RealmFuses.h
new file mode 100644
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+++ b/js/src/vm/RealmFuses.h
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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/. */
+
+#ifndef vm_RealmFuses_h
+#define vm_RealmFuses_h
+
+#include "vm/GuardFuse.h"
+
+namespace js {
+
+class NativeObject;
+struct RealmFuses;
+
+// [SMDOC] RealmFuses:
+//
+// Realm fuses are fuses associated with a specific realm. As a result,
+// popFuse for realmFuses has another argument, the set of realmFuses related to
+// the fuse being popped. This is used to find any dependent fuses in the realm
+// (rather than using the context).
+class RealmFuse : public GuardFuse {
+ public:
+  virtual void popFuse(JSContext* cx, RealmFuses& realmFuses) { popFuse(cx); }
+
+ protected:
+  virtual void popFuse(JSContext* cx) override { GuardFuse::popFuse(cx); }
+};
+
+struct OptimizeGetIteratorFuse final : public RealmFuse {
+  virtual const char* name() override { return "OptimizeGetIteratorFuse"; }
+  virtual bool checkInvariant(JSContext* cx) override;
+};
+
+struct PopsOptimizedGetIteratorFuse : public RealmFuse {
+  virtual void popFuse(JSContext* cx, RealmFuses& realmFuses) override;
+};
+
+struct ArrayPrototypeIteratorFuse final : public PopsOptimizedGetIteratorFuse {
+  virtual const char* name() override { return "ArrayPrototypeIteratorFuse"; }
+  virtual bool checkInvariant(JSContext* cx) override;
+};
+
+struct ArrayPrototypeIteratorNextFuse final
+    : public PopsOptimizedGetIteratorFuse {
+  virtual const char* name() override {
+    return "ArrayPrototypeIteratorNextFuse";
+  }
+  virtual bool checkInvariant(JSContext* cx) override;
+};
+
+// This fuse covers ArrayIteratorPrototype not having a return property;
+// however the fuse doesn't pop if a prototype acquires the return property.
+struct ArrayIteratorPrototypeHasNoReturnProperty final
+    : public PopsOptimizedGetIteratorFuse {
+  virtual const char* name() override {
+    return "ArrayIteratorPrototypeHasNoReturnProperty";
+  }
+  virtual bool checkInvariant(JSContext* cx) override;
+};
+
+// This fuse covers IteratorPrototype not having a return property;
+// however the fuse doesn't pop if a prototype acquires the return property.
+struct IteratorPrototypeHasNoReturnProperty final
+    : public PopsOptimizedGetIteratorFuse {
+  virtual const char* name() override {
+    return "IteratorPrototypeHasNoReturnProperty";
+  }
+  virtual bool checkInvariant(JSContext* cx) override;
+};
+
+struct ArrayIteratorPrototypeHasIteratorProto final
+    : public PopsOptimizedGetIteratorFuse {
+  virtual const char* name() override {
+    return "ArrayIteratorPrototypeHasIteratorProto";
+  }
+  virtual bool checkInvariant(JSContext* cx) override;
+};
+
+struct IteratorPrototypeHasObjectProto final
+    : public PopsOptimizedGetIteratorFuse {
+  virtual const char* name() override {
+    return "IteratorPrototypeHasObjectProto";
+  }
+  virtual bool checkInvariant(JSContext* cx) override;
+};
+
+struct ObjectPrototypeHasNoReturnProperty final
+    : public PopsOptimizedGetIteratorFuse {
+  virtual const char* name() override {
+    return "ObjectPrototypeHasNoReturnProperty";
+  }
+  virtual bool checkInvariant(JSContext* cx) override;
+};
+
+#define FOR_EACH_REALM_FUSE(FUSE)                                        \
+  FUSE(OptimizeGetIteratorFuse, optimizeGetIteratorFuse)                 \
+  FUSE(ArrayPrototypeIteratorFuse, arrayPrototypeIteratorFuse)           \
+  FUSE(ArrayPrototypeIteratorNextFuse, arrayPrototypeIteratorNextFuse)   \
+  FUSE(ArrayIteratorPrototypeHasNoReturnProperty,                        \
+       arrayIteratorPrototypeHasNoReturnProperty)                        \
+  FUSE(IteratorPrototypeHasNoReturnProperty,                             \
+       iteratorPrototypeHasNoReturnProperty)                             \
+  FUSE(ArrayIteratorPrototypeHasIteratorProto,                           \
+       arrayIteratorPrototypeHasIteratorProto)                           \
+  FUSE(IteratorPrototypeHasObjectProto, iteratorPrototypeHasObjectProto) \
+  FUSE(ObjectPrototypeHasNoReturnProperty, objectPrototypeHasNoReturnProperty)
+
+struct RealmFuses {
+  RealmFuses() = default;
+
+#define FUSE(Name, LowerName) Name LowerName{};
+  FOR_EACH_REALM_FUSE(FUSE)
+#undef FUSE
+
+  void assertInvariants(JSContext* cx) {
+// Generate the invariant checking calls.
+#define FUSE(Name, LowerName) LowerName.assertInvariant(cx);
+    FOR_EACH_REALM_FUSE(FUSE)
+#undef FUSE
+  }
+
+  // Code Generation Code:
+  enum class FuseIndex : uint8_t {
+  // Generate Fuse Indexes
+#define FUSE(Name, LowerName) Name,
+    FOR_EACH_REALM_FUSE(FUSE)
+#undef FUSE
+        LastFuseIndex
+  };
+
+  GuardFuse* getFuseByIndex(FuseIndex index) {
+    switch (index) {
+      // Return fuses.
+#define FUSE(Name, LowerName) \
+  case FuseIndex::Name:       \
+    return &this->LowerName;
+      FOR_EACH_REALM_FUSE(FUSE)
+#undef FUSE
+      default:
+        break;
+    }
+    MOZ_CRASH("Fuse Not Found");
+  }
+
+  static int32_t fuseOffsets[];
+  static const char* fuseNames[];
+
+  static int32_t offsetOfFuseWordRelativeToRealm(FuseIndex index);
+  static const char* getFuseName(FuseIndex index);
+};
+
+}  // namespace js
+
+#endif