Bug 1709695 - Only init PropertyInfos and sort IDs for resolving Xray properties once needed. r=nika

Most of the time, a lot of the WebIDL interfaces are never used with Xray wrappers.
We still always initialise the necessary PropertyInfo arrays whenever they're used
normally (not through Xray wrappers). I think we should postpone that initialisation
until we're actually going to use them with Xray wrappers.

Differential Revision: https://phabricator.services.mozilla.com/D114402

dom/bindings/BindingUtils.cpp

@@ -1275,8 +1275,8 @@ static inline JSPropertySpec::Name ToPropertySpecName(const char* name) {
 }
 
 template <typename SpecT>
-static bool InitIdsInternal(JSContext* cx, const Prefable<SpecT>* pref,
-                            PropertyInfo* infos, PropertyType type) {
+static bool InitPropertyInfos(JSContext* cx, const Prefable<SpecT>* pref,
+                              PropertyInfo* infos, PropertyType type) {
   MOZ_ASSERT(pref);
   MOZ_ASSERT(pref->specs);
 
@@ -1308,24 +1308,25 @@ static bool InitIdsInternal(JSContext* cx, const Prefable<SpecT>* pref,
   return true;
 }
 
-#define INIT_IDS_IF_DEFINED(TypeName)                                 \
-  {                                                                   \
-    if (nativeProperties->Has##TypeName##s() &&                       \
-        !InitIdsInternal(cx, nativeProperties->TypeName##s(),         \
-                         nativeProperties->TypeName##PropertyInfos(), \
-                         e##TypeName)) {                              \
-      return false;                                                   \
-    }                                                                 \
+#define INIT_PROPERTY_INFOS_IF_DEFINED(TypeName)                        \
+  {                                                                     \
+    if (nativeProperties->Has##TypeName##s() &&                         \
+        !InitPropertyInfos(cx, nativeProperties->TypeName##s(),         \
+                           nativeProperties->TypeName##PropertyInfos(), \
+                           e##TypeName)) {                              \
+      return false;                                                     \
+    }                                                                   \
   }
 
-bool InitIds(JSContext* cx, const NativeProperties* nativeProperties) {
-  INIT_IDS_IF_DEFINED(StaticMethod);
-  INIT_IDS_IF_DEFINED(StaticAttribute);
-  INIT_IDS_IF_DEFINED(Method);
-  INIT_IDS_IF_DEFINED(Attribute);
-  INIT_IDS_IF_DEFINED(UnforgeableMethod);
-  INIT_IDS_IF_DEFINED(UnforgeableAttribute);
-  INIT_IDS_IF_DEFINED(Constant);
+static bool InitPropertyInfos(JSContext* cx,
+                              const NativeProperties* nativeProperties) {
+  INIT_PROPERTY_INFOS_IF_DEFINED(StaticMethod);
+  INIT_PROPERTY_INFOS_IF_DEFINED(StaticAttribute);
+  INIT_PROPERTY_INFOS_IF_DEFINED(Method);
+  INIT_PROPERTY_INFOS_IF_DEFINED(Attribute);
+  INIT_PROPERTY_INFOS_IF_DEFINED(UnforgeableMethod);
+  INIT_PROPERTY_INFOS_IF_DEFINED(UnforgeableAttribute);
+  INIT_PROPERTY_INFOS_IF_DEFINED(Constant);
 
   // Initialize and sort the index array.
   uint16_t* indices = nativeProperties->sortedPropertyIndices;
@@ -1341,7 +1342,26 @@ bool InitIds(JSContext* cx, const NativeProperties* nativeProperties) {
   return true;
 }
 
-#undef INIT_IDS_IF_DEFINED
+#undef INIT_PROPERTY_INFOS_IF_DEFINED
+
+static inline bool InitPropertyInfos(
+    JSContext* aCx, const NativePropertiesHolder& nativeProperties) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (!*nativeProperties.inited) {
+    if (nativeProperties.regular &&
+        !InitPropertyInfos(aCx, nativeProperties.regular)) {
+      return false;
+    }
+    if (nativeProperties.chromeOnly &&
+        !InitPropertyInfos(aCx, nativeProperties.chromeOnly)) {
+      return false;
+    }
+    *nativeProperties.inited = true;
+  }
+
+  return true;
+}
 
 void GetInterfaceImpl(JSContext* aCx, nsIInterfaceRequestor* aRequestor,
                       nsWrapperCache* aCache, JS::Handle<JS::Value> aIID,
@@ -1678,6 +1698,11 @@ static bool ResolvePrototypeOrConstructor(
 
   const NativePropertiesHolder& nativePropertiesHolder =
       nativePropertyHooks->mNativeProperties;
+
+  if (!InitPropertyInfos(cx, nativePropertiesHolder)) {
+    return false;
+  }
+
   const NativeProperties* nativeProperties = nullptr;
   const PropertyInfo* found = nullptr;
 
@@ -1949,6 +1974,10 @@ bool XrayOwnNativePropertyKeys(JSContext* cx, JS::Handle<JSObject*> wrapper,
   const NativePropertiesHolder& nativeProperties =
       nativePropertyHooks->mNativeProperties;
 
+  if (!InitPropertyInfos(cx, nativeProperties)) {
+    return false;
+  }
+
   if (nativeProperties.regular &&
       !XrayOwnPropertyKeys(cx, wrapper, obj, flags, props, type,
                            nativeProperties.regular)) {
@@ -2053,13 +2082,15 @@ JSObject* GetCachedSlotStorageObjectSlow(JSContext* cx,
 
 DEFINE_XRAY_EXPANDO_CLASS(, DefaultXrayExpandoObjectClass, 0);
 
-NativePropertyHooks sEmptyNativePropertyHooks = {nullptr,
-                                                 nullptr,
-                                                 nullptr,
-                                                 {nullptr, nullptr},
-                                                 prototypes::id::_ID_Count,
-                                                 constructors::id::_ID_Count,
-                                                 nullptr};
+bool sEmptyNativePropertiesInited = true;
+NativePropertyHooks sEmptyNativePropertyHooks = {
+    nullptr,
+    nullptr,
+    nullptr,
+    {nullptr, nullptr, &sEmptyNativePropertiesInited},
+    prototypes::id::_ID_Count,
+    constructors::id::_ID_Count,
+    nullptr};
 
 const JSClassOps sBoringInterfaceObjectClassClassOps = {
     nullptr,             /* addProperty */

dom/bindings/BindingUtils.h

@@ -1770,8 +1770,6 @@ static inline bool AtomizeAndPinJSString(JSContext* cx, jsid& id,
   return false;
 }
 
-bool InitIds(JSContext* cx, const NativeProperties* properties);
-
 void GetInterfaceImpl(JSContext* aCx, nsIInterfaceRequestor* aRequestor,
                       nsWrapperCache* aCache, JS::Handle<JS::Value> aIID,
                       JS::MutableHandle<JS::Value> aRetval,

dom/bindings/Codegen.py

@@ -544,11 +544,12 @@ class CGNativePropertyHooks(CGThing):
 
         return fill(
             """
+            bool sNativePropertiesInited = false;
             const NativePropertyHooks sNativePropertyHooks[] = { {
               ${resolveOwnProperty},
               ${enumerateOwnProperties},
               ${deleteNamedProperty},
-              { ${regular}, ${chrome} },
+              { ${regular}, ${chrome}, &sNativePropertiesInited },
               ${prototypeID},
               ${constructorID},
               ${parentHooks},
@@ -2362,11 +2363,12 @@ class CGLegacyFactoryFunctions(CGThing):
 
         return fill(
             """
+            bool sLegacyFactoryFunctionNativePropertiesInited = true;
             const NativePropertyHooks sLegacyFactoryFunctionNativePropertyHooks = {
                 nullptr,
                 nullptr,
                 nullptr,
-                { nullptr, nullptr },
+                { nullptr, nullptr, &sLegacyFactoryFunctionNativePropertiesInited },
                 prototypes::id::${name},
                 ${constructorID},
                 nullptr
@@ -3614,36 +3616,6 @@ class CGCreateInterfaceObjectsMethod(CGAbstractMethod):
             getConstructorProto=getConstructorProto,
         )
 
-        idsToInit = []
-        # There is no need to init any IDs in bindings that don't want Xrays.
-        if self.descriptor.wantsXrays:
-            if self.properties.hasNonChromeOnly():
-                idsToInit.append("sNativeProperties")
-            if self.properties.hasChromeOnly():
-                idsToInit.append("sChromeOnlyNativeProperties")
-        if len(idsToInit) > 0:
-            initIdCalls = [
-                "!InitIds(aCx, %s.Upcast())" % (properties) for properties in idsToInit
-            ]
-            idsInitedFlag = CGGeneric(
-                "static Atomic<bool, Relaxed> sIdsInited(false);\n"
-            )
-            setFlag = CGGeneric("sIdsInited = true;\n")
-            initIdConditionals = [
-                CGIfWrapper(CGGeneric("return;\n"), call) for call in initIdCalls
-            ]
-            initIds = CGList(
-                [
-                    idsInitedFlag,
-                    CGIfWrapper(
-                        CGList(initIdConditionals + [setFlag]),
-                        "!sIdsInited && NS_IsMainThread()",
-                    ),
-                ]
-            )
-        else:
-            initIds = None
-
         if self.descriptor.interface.ctor():
             constructArgs = methodLength(self.descriptor.interface.ctor())
         else:
@@ -3936,7 +3908,6 @@ class CGCreateInterfaceObjectsMethod(CGAbstractMethod):
             [
                 getParentProto,
                 getConstructorProto,
-                initIds,
                 CGGeneric(call),
                 defineAliases,
                 unforgeableHolderSetup,

dom/bindings/DOMJSClass.h

@@ -384,6 +384,11 @@ typedef NativePropertiesN<7> NativeProperties;
 struct NativePropertiesHolder {
   const NativeProperties* regular;
   const NativeProperties* chromeOnly;
+  // Points to a static bool that's set to true once the regular and chromeOnly
+  // NativeProperties have been inited. This is a pointer to a bool instead of
+  // a bool value because NativePropertiesHolder is stored by value in
+  // a static const NativePropertyHooks.
+  bool* inited;
 };
 
 // Helper structure for Xrays for DOM binding objects. The same instance is used