1 files changed, 159 insertions, 0 deletions
diff --git a/js/src/gc/Policy.h b/js/src/gc/Policy.h
new file mode 100644
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+++ b/js/src/gc/Policy.h
@@ -0,0 +1,159 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * 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/. */
+
+/* JS Garbage Collector. */
+
+#ifndef gc_Policy_h
+#define gc_Policy_h
+
+#include "mozilla/TypeTraits.h"
+#include "gc/Barrier.h"
+#include "gc/Marking.h"
+#include "js/GCPolicyAPI.h"
+
+// Forward declare the types we're defining policies for. This file is
+// included in all places that define GC things, so the real definitions
+// will be available when we do template expansion, allowing for use of
+// static members in the underlying types. We cannot, however, use
+// static_assert to verify relations between types.
+class JSLinearString;
+namespace js {
+class AccessorShape;
+class ArgumentsObject;
+class ArrayBufferObject;
+class ArrayBufferObjectMaybeShared;
+class ArrayBufferViewObject;
+class ArrayObject;
+class BaseShape;
+class DebugEnvironmentProxy;
+class DebuggerFrame;
+class ExportEntryObject;
+class EnvironmentObject;
+class GlobalObject;
+class ImportEntryObject;
+class LazyScript;
+class LexicalEnvironmentObject;
+class ModuleEnvironmentObject;
+class ModuleNamespaceObject;
+class ModuleObject;
+class NativeObject;
+class ObjectGroup;
+class PlainObject;
+class PropertyName;
+class RegExpObject;
+class SavedFrame;
+class Scope;
+class EnvironmentObject;
+class ScriptSourceObject;
+class Shape;
+class SharedArrayBufferObject;
+class StructTypeDescr;
+class UnownedBaseShape;
+class WasmMemoryObject;
+namespace jit {
+class JitCode;
+} // namespace jit
+} // namespace js
+
+// Expand the given macro D for each valid GC reference type.
+#define FOR_EACH_INTERNAL_GC_POINTER_TYPE(D) \
+    D(JSFlatString*) \
+    D(JSLinearString*) \
+    D(js::AccessorShape*) \
+    D(js::ArgumentsObject*) \
+    D(js::ArrayBufferObject*) \
+    D(js::ArrayBufferObjectMaybeShared*) \
+    D(js::ArrayBufferViewObject*) \
+    D(js::ArrayObject*) \
+    D(js::BaseShape*) \
+    D(js::DebugEnvironmentProxy*) \
+    D(js::DebuggerFrame*) \
+    D(js::ExportEntryObject*) \
+    D(js::EnvironmentObject*) \
+    D(js::GlobalObject*) \
+    D(js::ImportEntryObject*) \
+    D(js::LazyScript*) \
+    D(js::LexicalEnvironmentObject*) \
+    D(js::ModuleEnvironmentObject*) \
+    D(js::ModuleNamespaceObject*) \
+    D(js::ModuleObject*) \
+    D(js::NativeObject*) \
+    D(js::ObjectGroup*) \
+    D(js::PlainObject*) \
+    D(js::PropertyName*) \
+    D(js::RegExpObject*) \
+    D(js::SavedFrame*) \
+    D(js::Scope*) \
+    D(js::ScriptSourceObject*) \
+    D(js::Shape*) \
+    D(js::SharedArrayBufferObject*) \
+    D(js::StructTypeDescr*) \
+    D(js::UnownedBaseShape*) \
+    D(js::WasmInstanceObject*) \
+    D(js::WasmMemoryObject*) \
+    D(js::WasmTableObject*) \
+    D(js::jit::JitCode*)
+
+// Expand the given macro D for each internal tagged GC pointer type.
+#define FOR_EACH_INTERNAL_TAGGED_GC_POINTER_TYPE(D) \
+    D(js::TaggedProto)
+
+// Expand the macro D for every GC reference type that we know about.
+#define FOR_EACH_GC_POINTER_TYPE(D) \
+    FOR_EACH_PUBLIC_GC_POINTER_TYPE(D) \
+    FOR_EACH_PUBLIC_TAGGED_GC_POINTER_TYPE(D) \
+    FOR_EACH_INTERNAL_GC_POINTER_TYPE(D) \
+    FOR_EACH_INTERNAL_TAGGED_GC_POINTER_TYPE(D)
+
+namespace js {
+
+// Define the GCPolicy for all internal pointers.
+template <typename T>
+struct InternalGCPointerPolicy {
+    using Type = typename mozilla::RemovePointer<T>::Type;
+    static T initial() { return nullptr; }
+    static void preBarrier(T v) { Type::writeBarrierPre(v); }
+    static void postBarrier(T* vp, T prev, T next) { Type::writeBarrierPost(vp, prev, next); }
+    static void readBarrier(T v) { Type::readBarrier(v); }
+    static void trace(JSTracer* trc, T* vp, const char* name) {
+        TraceManuallyBarrieredEdge(trc, vp, name);
+    }
+};
+
+} // namespace js
+
+namespace JS {
+
+#define DEFINE_INTERNAL_GC_POLICY(type) \
+    template <> struct GCPolicy<type> : public js::InternalGCPointerPolicy<type> {};
+FOR_EACH_INTERNAL_GC_POINTER_TYPE(DEFINE_INTERNAL_GC_POLICY)
+#undef DEFINE_INTERNAL_GC_POLICY
+
+template <typename T>
+struct GCPolicy<js::HeapPtr<T>>
+{
+    static void trace(JSTracer* trc, js::HeapPtr<T>* thingp, const char* name) {
+        js::TraceEdge(trc, thingp, name);
+    }
+    static bool needsSweep(js::HeapPtr<T>* thingp) {
+        return js::gc::IsAboutToBeFinalized(thingp);
+    }
+};
+
+template <typename T>
+struct GCPolicy<js::ReadBarriered<T>>
+{
+    static void trace(JSTracer* trc, js::ReadBarriered<T>* thingp, const char* name) {
+        js::TraceEdge(trc, thingp, name);
+    }
+    static bool needsSweep(js::ReadBarriered<T>* thingp) {
+        return js::gc::IsAboutToBeFinalized(thingp);
+    }
+};
+
+} // namespace JS
+
+#endif // gc_Policy_h