js/src/gc/TraceKind.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 gc_TraceKind_h
   8 #define gc_TraceKind_h
   9
  10 #include "js/TraceKind.h"
  11
  12 namespace js {
  13 namespace gc {
  14
  15 // Map from all trace kinds to the base GC type.
  16 template <JS::TraceKind kind>
  17 struct MapTraceKindToType {};
  18
  19 #define DEFINE_TRACE_KIND_MAP(name, type, _, _1)   \
  20   template <>                                      \
  21   struct MapTraceKindToType<JS::TraceKind::name> { \
  22     using Type = type;                             \
  23   };
  24 JS_FOR_EACH_TRACEKIND(DEFINE_TRACE_KIND_MAP);
  25 #undef DEFINE_TRACE_KIND_MAP
  26
  27 // Map from a possibly-derived type to the base GC type.
  28 template <typename T>
  29 struct BaseGCType {
  30   using type =
  31       typename MapTraceKindToType<JS::MapTypeToTraceKind<T>::kind>::Type;
  32   static_assert(std::is_base_of_v<type, T>, "Failed to find base type");
  33 };
  34
  35 template <typename T>
  36 struct TraceKindCanBeGray {};
  37 #define EXPAND_TRACEKIND_DEF(_, type, canBeGray, _1) \
  38   template <>                                        \
  39   struct TraceKindCanBeGray<type> {                  \
  40     static constexpr bool value = canBeGray;         \
  41   };
  42 JS_FOR_EACH_TRACEKIND(EXPAND_TRACEKIND_DEF)
  43 #undef EXPAND_TRACEKIND_DEF
  44
  45 struct TraceKindCanBeGrayFunctor {
  46   template <typename T>
  47   bool operator()() {
  48     return TraceKindCanBeGray<T>::value;
  49   }
  50 };
  51
  52 static inline bool TraceKindCanBeMarkedGray(JS::TraceKind kind) {
  53   return DispatchTraceKindTyped(TraceKindCanBeGrayFunctor(), kind);
  54 }
  55
  56 } /* namespace gc */
  57 } /* namespace js */
  58
  59 #endif /* gc_TraceKind_h */