js/src/vm/ObjectFlags-inl.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef vm_ObjectFlags_inl_h
   8 #define vm_ObjectFlags_inl_h
   9
  10 #include "vm/ObjectFlags.h"
  11
  12 #include "builtin/Array.h"
  13 #include "vm/JSAtomState.h"
  14 #include "vm/JSContext.h"
  15 #include "vm/PlainObject.h"
  16 #include "vm/PropertyInfo.h"
  17
  18 namespace js {
  19
  20 MOZ_ALWAYS_INLINE ObjectFlags
  21 GetObjectFlagsForNewProperty(const JSClass* clasp, ObjectFlags flags, jsid id,
  22                              PropertyFlags propFlags, JSContext* cx) {
  23   uint32_t index;
  24   if (IdIsIndex(id, &index)) {
  25     flags.setFlag(ObjectFlag::Indexed);
  26   } else if (id.isSymbol() && id.toSymbol()->isInterestingSymbol()) {
  27     flags.setFlag(ObjectFlag::HasInterestingSymbol);
  28   }
  29
  30   if ((!propFlags.isDataProperty() || !propFlags.writable()) &&
  31       clasp == &PlainObject::class_ && !id.isAtom(cx->names().proto_)) {
  32     flags.setFlag(ObjectFlag::HasNonWritableOrAccessorPropExclProto);
  33   }
  34
  35   // https://tc39.es/ecma262/multipage/ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-get-p-receiver
  36   // Proxy.[[Get]] or [[Set]] Step 9
  37   if (!propFlags.configurable()) {
  38     MOZ_ASSERT(clasp->isNativeObject());
  39     // NOTE: there is a hole which this flag does not cover, which is if the
  40     // class has a resolve hook which could lazily define a non-configurable
  41     // non-writable property. We can just look this up directly though in the
  42     // JIT.
  43     if (propFlags.isDataProperty() && !propFlags.writable()) {
  44       flags.setFlag(ObjectFlag::NeedsProxyGetSetResultValidation);
  45     } else if (propFlags.isAccessorProperty()) {
  46       // This will cover us for both get trap validation and set trap
  47       // validation. We could be more aggressive, because what we really
  48       // care about is if there is a getter but not a setter and vice
  49       // versa, but the first pass at doing that resulted in test
  50       // failures. We'll need to work on that as a follow-up if it is
  51       // important.
  52       flags.setFlag(ObjectFlag::NeedsProxyGetSetResultValidation);
  53     }
  54   }
  55
  56   if (propFlags.enumerable()) {
  57     flags.setFlag(ObjectFlag::HasEnumerable);
  58   }
  59
  60   return flags;
  61 }
  62
  63 // When reusing another shape's PropMap, we need to copy the object flags that
  64 // are based on property information. This is equivalent to (but faster than)
  65 // calling GetObjectFlagsForNewProperty for all properties in the map.
  66 inline ObjectFlags CopyPropMapObjectFlags(ObjectFlags dest,
  67                                           ObjectFlags source) {
  68   if (source.hasFlag(ObjectFlag::Indexed)) {
  69     dest.setFlag(ObjectFlag::Indexed);
  70   }
  71   if (source.hasFlag(ObjectFlag::HasInterestingSymbol)) {
  72     dest.setFlag(ObjectFlag::HasInterestingSymbol);
  73   }
  74   if (source.hasFlag(ObjectFlag::HasNonWritableOrAccessorPropExclProto)) {
  75     dest.setFlag(ObjectFlag::HasNonWritableOrAccessorPropExclProto);
  76   }
  77   if (source.hasFlag(ObjectFlag::NeedsProxyGetSetResultValidation)) {
  78     dest.setFlag(ObjectFlag::NeedsProxyGetSetResultValidation);
  79   }
  80   return dest;
  81 }
  82
  83 }  // namespace js
  84
  85 #endif /* vm_ObjectFlags_inl_h */