js/src/gc/AllocKind.h

   1
   2 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   3  * vim: set ts=8 sts=2 et sw=2 tw=80:
   4  * This Source Code Form is subject to the terms of the Mozilla Public
   5  * License, v. 2.0. If a copy of the MPL was not distributed with this
   6  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   7
   8 /*
   9  * GC-internal definition of GC cell kinds.
  10  */
  11
  12 #ifndef gc_AllocKind_h
  13 #define gc_AllocKind_h
  14
  15 #include "mozilla/EnumeratedArray.h"
  16 #include "mozilla/EnumeratedRange.h"
  17
  18 #include <iterator>
  19 #include <stdint.h>
  20
  21 #include "js/TraceKind.h"
  22
  23 class JSDependentString;
  24 class JSExternalString;
  25 class JSFatInlineString;
  26 class JSLinearString;
  27 class JSRope;
  28 class JSThinInlineString;
  29
  30 namespace js {
  31
  32 class CompactPropMap;
  33 class FatInlineAtom;
  34 class NormalAtom;
  35 class NormalPropMap;
  36 class DictionaryPropMap;
  37 class DictionaryShape;
  38 class SharedShape;
  39 class ProxyShape;
  40 class WasmGCShape;
  41
  42 namespace gc {
  43
  44 // The GC allocation kinds.
  45 //
  46 // These are defined by macros which enumerate the different allocation kinds
  47 // and supply the following information:
  48 //
  49 //  - the corresponding AllocKind
  50 //  - their JS::TraceKind
  51 //  - their C++ base type
  52 //  - a C++ type of the correct size
  53 //  - whether they can be finalized on the background thread
  54 //  - whether they can be allocated in the nursery (this is true for foreground
  55 //    finalized objects but these will can only actually be allocated in the
  56 //    nursery if JSCLASS_SKIP_NURSERY_FINALIZE is set)
  57 //  - whether they can be compacted
  58
  59 // clang-format off
  60 #define FOR_EACH_OBJECT_ALLOCKIND(D) \
  61  /* AllocKind              TraceKind     TypeName           SizedType          BGFinal Nursery Compact */ \
  62     D(FUNCTION,            Object,       JSObject,          JSObject_Slots4,   true,   true,   true) \
  63     D(FUNCTION_EXTENDED,   Object,       JSObject,          JSObject_Slots6,   true,   true,   true) \
  64     D(OBJECT0,             Object,       JSObject,          JSObject_Slots0,   false,  true,   true) \
  65     D(OBJECT0_BACKGROUND,  Object,       JSObject,          JSObject_Slots0,   true,   true,   true) \
  66     D(OBJECT2,             Object,       JSObject,          JSObject_Slots2,   false,  true,   true) \
  67     D(OBJECT2_BACKGROUND,  Object,       JSObject,          JSObject_Slots2,   true,   true,   true) \
  68     D(ARRAYBUFFER4,        Object,       JSObject,          JSObject_Slots4,   true,   true,   true) \
  69     D(OBJECT4,             Object,       JSObject,          JSObject_Slots4,   false,  true,   true) \
  70     D(OBJECT4_BACKGROUND,  Object,       JSObject,          JSObject_Slots4,   true,   true,   true) \
  71     D(ARRAYBUFFER8,        Object,       JSObject,          JSObject_Slots8,   true,   true,   true) \
  72     D(OBJECT8,             Object,       JSObject,          JSObject_Slots8,   false,  true,   true) \
  73     D(OBJECT8_BACKGROUND,  Object,       JSObject,          JSObject_Slots8,   true,   true,   true) \
  74     D(ARRAYBUFFER12,       Object,       JSObject,          JSObject_Slots12,  true,   true,   true) \
  75     D(OBJECT12,            Object,       JSObject,          JSObject_Slots12,  false,  true,   true) \
  76     D(OBJECT12_BACKGROUND, Object,       JSObject,          JSObject_Slots12,  true,   true,   true) \
  77     D(ARRAYBUFFER16,       Object,       JSObject,          JSObject_Slots16,  true,   true,   true) \
  78     D(OBJECT16,            Object,       JSObject,          JSObject_Slots16,  false,  true,   true) \
  79     D(OBJECT16_BACKGROUND, Object,       JSObject,          JSObject_Slots16,  true,   true,   true)
  80
  81 #define FOR_EACH_NONOBJECT_NONNURSERY_ALLOCKIND(D) \
  82  /* AllocKind              TraceKind     TypeName               SizedType              BGFinal Nursery Compact */ \
  83     D(SCRIPT,              Script,       js::BaseScript,        js::BaseScript,        false,  false,  true) \
  84     D(SHAPE,               Shape,        js::Shape,             js::SizedShape,        true,   false,  true) \
  85     D(BASE_SHAPE,          BaseShape,    js::BaseShape,         js::BaseShape,         true,   false,  true) \
  86     D(GETTER_SETTER,       GetterSetter, js::GetterSetter,      js::GetterSetter,      true,   false,  true) \
  87     D(COMPACT_PROP_MAP,    PropMap,      js::CompactPropMap,    js::CompactPropMap,    true,   false,  true) \
  88     D(NORMAL_PROP_MAP,     PropMap,      js::NormalPropMap,     js::NormalPropMap,     true,   false,  true) \
  89     D(DICT_PROP_MAP,       PropMap,      js::DictionaryPropMap, js::DictionaryPropMap, true,   false,  true) \
  90     D(EXTERNAL_STRING,     String,       JSExternalString,      JSExternalString,      true,   false,  true) \
  91     D(FAT_INLINE_ATOM,     String,       js::FatInlineAtom,     js::FatInlineAtom,     true,   false,  false) \
  92     D(ATOM,                String,       js::NormalAtom,        js::NormalAtom,        true,   false,  false) \
  93     D(SYMBOL,              Symbol,       JS::Symbol,            JS::Symbol,            true,   false,  false) \
  94     D(JITCODE,             JitCode,      js::jit::JitCode,      js::jit::JitCode,      false,  false,  false) \
  95     D(SCOPE,               Scope,        js::Scope,             js::Scope,             true,   false,  true) \
  96     D(REGEXP_SHARED,       RegExpShared, js::RegExpShared,      js::RegExpShared,      true,   false,  true)
  97
  98 #define FOR_EACH_NONOBJECT_NURSERY_ALLOCKIND(D) \
  99  /* AllocKind              TraceKind     TypeName           SizedType          BGFinal Nursery Compact */ \
 100     D(BIGINT,              BigInt,       JS::BigInt,        JS::BigInt,        true,   true,  true)
 101
 102 #define FOR_EACH_NURSERY_STRING_ALLOCKIND(D) \
 103     D(FAT_INLINE_STRING,   String,        JSFatInlineString, JSFatInlineString, true,   true,  true) \
 104     D(STRING,              String,        JSString,          JSString,          true,   true,  true)
 105 // clang-format on
 106
 107 #define FOR_EACH_NONOBJECT_ALLOCKIND(D)      \
 108   FOR_EACH_NONOBJECT_NONNURSERY_ALLOCKIND(D) \
 109   FOR_EACH_NONOBJECT_NURSERY_ALLOCKIND(D)    \
 110   FOR_EACH_NURSERY_STRING_ALLOCKIND(D)
 111
 112 #define FOR_EACH_ALLOCKIND(D)  \
 113   FOR_EACH_OBJECT_ALLOCKIND(D) \
 114   FOR_EACH_NONOBJECT_ALLOCKIND(D)
 115
 116 #define DEFINE_ALLOC_KIND(allocKind, _1, _2, _3, _4, _5, _6) allocKind,
 117 enum class AllocKind : uint8_t {
 118   // clang-format off
 119     FOR_EACH_OBJECT_ALLOCKIND(DEFINE_ALLOC_KIND)
 120
 121     OBJECT_LIMIT,
 122     OBJECT_LAST = OBJECT_LIMIT - 1,
 123
 124     FOR_EACH_NONOBJECT_ALLOCKIND(DEFINE_ALLOC_KIND)
 125
 126     LIMIT,
 127     LAST = LIMIT - 1,
 128
 129     FIRST = 0,
 130     OBJECT_FIRST = FUNCTION // Hardcoded to first object kind.
 131   // clang-format on
 132 };
 133 #undef DEFINE_ALLOC_KIND
 134
 135 static_assert(int(AllocKind::FIRST) == 0,
 136               "Various places depend on AllocKind starting at 0");
 137 static_assert(int(AllocKind::OBJECT_FIRST) == 0,
 138               "OBJECT_FIRST must be defined as the first object kind");
 139
 140 constexpr size_t AllocKindCount = size_t(AllocKind::LIMIT);
 141
 142 /*
 143  * This flag allows an allocation site to request a specific heap based upon the
 144  * estimated lifetime or lifetime requirements of objects allocated from that
 145  * site.
 146  */
 147 enum InitialHeap : uint8_t { DefaultHeap, TenuredHeap };
 148
 149 inline bool IsAllocKind(AllocKind kind) {
 150   return kind >= AllocKind::FIRST && kind <= AllocKind::LIMIT;
 151 }
 152
 153 inline bool IsValidAllocKind(AllocKind kind) {
 154   return kind >= AllocKind::FIRST && kind <= AllocKind::LAST;
 155 }
 156
 157 const char* AllocKindName(AllocKind kind);
 158
 159 inline bool IsObjectAllocKind(AllocKind kind) {
 160   return kind >= AllocKind::OBJECT_FIRST && kind <= AllocKind::OBJECT_LAST;
 161 }
 162
 163 inline bool IsShapeAllocKind(AllocKind kind) {
 164   return kind == AllocKind::SHAPE;
 165 }
 166
 167 // Returns a sequence for use in a range-based for loop,
 168 // to iterate over all alloc kinds.
 169 inline auto AllAllocKinds() {
 170   return mozilla::MakeEnumeratedRange(AllocKind::FIRST, AllocKind::LIMIT);
 171 }
 172
 173 // Returns a sequence for use in a range-based for loop,
 174 // to iterate over all object alloc kinds.
 175 inline auto ObjectAllocKinds() {
 176   return mozilla::MakeEnumeratedRange(AllocKind::OBJECT_FIRST,
 177                                       AllocKind::OBJECT_LIMIT);
 178 }
 179
 180 // Returns a sequence for use in a range-based for loop,
 181 // to iterate over alloc kinds from |first| to |limit|, exclusive.
 182 inline auto SomeAllocKinds(AllocKind first = AllocKind::FIRST,
 183                            AllocKind limit = AllocKind::LIMIT) {
 184   MOZ_ASSERT(IsAllocKind(first), "|first| is not a valid AllocKind!");
 185   MOZ_ASSERT(IsAllocKind(limit), "|limit| is not a valid AllocKind!");
 186   return mozilla::MakeEnumeratedRange(first, limit);
 187 }
 188
 189 // AllAllocKindArray<ValueType> gives an enumerated array of ValueTypes,
 190 // with each index corresponding to a particular alloc kind.
 191 template <typename ValueType>
 192 using AllAllocKindArray =
 193     mozilla::EnumeratedArray<AllocKind, AllocKind::LIMIT, ValueType>;
 194
 195 // ObjectAllocKindArray<ValueType> gives an enumerated array of ValueTypes,
 196 // with each index corresponding to a particular object alloc kind.
 197 template <typename ValueType>
 198 using ObjectAllocKindArray =
 199     mozilla::EnumeratedArray<AllocKind, AllocKind::OBJECT_LIMIT, ValueType>;
 200
 201 /*
 202  * Map from C++ type to alloc kind for non-object types. JSObject does not have
 203  * a 1:1 mapping, so must use Arena::thingSize.
 204  *
 205  * The AllocKind is available as MapTypeToAllocKind<SomeType>::kind.
 206  *
 207  * There are specializations for strings and shapes since more than one derived
 208  * type shares the same alloc kind.
 209  */
 210 template <typename T>
 211 struct MapTypeToAllocKind {};
 212 #define EXPAND_MAPTYPETOALLOCKIND(allocKind, traceKind, type, sizedType, \
 213                                   bgFinal, nursery, compact)             \
 214   template <>                                                            \
 215   struct MapTypeToAllocKind<type> {                                      \
 216     static const AllocKind kind = AllocKind::allocKind;                  \
 217   };
 218 FOR_EACH_NONOBJECT_ALLOCKIND(EXPAND_MAPTYPETOALLOCKIND)
 219 #undef EXPAND_MAPTYPETOALLOCKIND
 220
 221 template <>
 222 struct MapTypeToAllocKind<JSDependentString> {
 223   static const AllocKind kind = AllocKind::STRING;
 224 };
 225 template <>
 226 struct MapTypeToAllocKind<JSRope> {
 227   static const AllocKind kind = AllocKind::STRING;
 228 };
 229 template <>
 230 struct MapTypeToAllocKind<JSLinearString> {
 231   static const AllocKind kind = AllocKind::STRING;
 232 };
 233 template <>
 234 struct MapTypeToAllocKind<JSThinInlineString> {
 235   static const AllocKind kind = AllocKind::STRING;
 236 };
 237
 238 template <>
 239 struct MapTypeToAllocKind<js::SharedShape> {
 240   static const AllocKind kind = AllocKind::SHAPE;
 241 };
 242 template <>
 243 struct MapTypeToAllocKind<js::DictionaryShape> {
 244   static const AllocKind kind = AllocKind::SHAPE;
 245 };
 246 template <>
 247 struct MapTypeToAllocKind<js::ProxyShape> {
 248   static const AllocKind kind = AllocKind::SHAPE;
 249 };
 250 template <>
 251 struct MapTypeToAllocKind<js::WasmGCShape> {
 252   static const AllocKind kind = AllocKind::SHAPE;
 253 };
 254
 255 static inline JS::TraceKind MapAllocToTraceKind(AllocKind kind) {
 256   static const JS::TraceKind map[] = {
 257 #define EXPAND_ELEMENT(allocKind, traceKind, type, sizedType, bgFinal, \
 258                        nursery, compact)                               \
 259   JS::TraceKind::traceKind,
 260       FOR_EACH_ALLOCKIND(EXPAND_ELEMENT)
 261 #undef EXPAND_ELEMENT
 262   };
 263
 264   static_assert(std::size(map) == AllocKindCount,
 265                 "AllocKind-to-TraceKind mapping must be in sync");
 266   return map[size_t(kind)];
 267 }
 268
 269 static inline bool IsNurseryAllocable(AllocKind kind) {
 270   MOZ_ASSERT(IsValidAllocKind(kind));
 271
 272   static const bool map[] = {
 273 #define DEFINE_NURSERY_ALLOCABLE(_1, _2, _3, _4, _5, nursery, _6) nursery,
 274       FOR_EACH_ALLOCKIND(DEFINE_NURSERY_ALLOCABLE)
 275 #undef DEFINE_NURSERY_ALLOCABLE
 276   };
 277
 278   static_assert(std::size(map) == AllocKindCount,
 279                 "IsNurseryAllocable sanity check");
 280   return map[size_t(kind)];
 281 }
 282
 283 static inline bool IsBackgroundFinalized(AllocKind kind) {
 284   MOZ_ASSERT(IsValidAllocKind(kind));
 285
 286   static const bool map[] = {
 287 #define DEFINE_BACKGROUND_FINALIZED(_1, _2, _3, _4, bgFinal, _5, _6) bgFinal,
 288       FOR_EACH_ALLOCKIND(DEFINE_BACKGROUND_FINALIZED)
 289 #undef DEFINE_BACKGROUND_FINALIZED
 290   };
 291
 292   static_assert(std::size(map) == AllocKindCount,
 293                 "IsBackgroundFinalized sanity check");
 294   return map[size_t(kind)];
 295 }
 296
 297 static inline bool IsForegroundFinalized(AllocKind kind) {
 298   return !IsBackgroundFinalized(kind);
 299 }
 300
 301 static inline bool IsCompactingKind(AllocKind kind) {
 302   MOZ_ASSERT(IsValidAllocKind(kind));
 303
 304   static const bool map[] = {
 305 #define DEFINE_COMPACTING_KIND(_1, _2, _3, _4, _5, _6, compact) compact,
 306       FOR_EACH_ALLOCKIND(DEFINE_COMPACTING_KIND)
 307 #undef DEFINE_COMPACTING_KIND
 308   };
 309
 310   static_assert(std::size(map) == AllocKindCount,
 311                 "IsCompactingKind sanity check");
 312   return map[size_t(kind)];
 313 }
 314
 315 static inline bool IsMovableKind(AllocKind kind) {
 316   return IsNurseryAllocable(kind) || IsCompactingKind(kind);
 317 }
 318
 319 } /* namespace gc */
 320 } /* namespace js */
 321
 322 #endif /* gc_AllocKind_h */