Line data Source code
1 : // Copyright 2014 the V8 project authors. All rights reserved.
2 : // Use of this source code is governed by a BSD-style license that can be
3 : // found in the LICENSE file.
4 :
5 : #ifndef V8_COMPILER_TYPES_H_
6 : #define V8_COMPILER_TYPES_H_
7 :
8 : #include "src/base/compiler-specific.h"
9 : #include "src/compiler/js-heap-broker.h"
10 : #include "src/conversions.h"
11 : #include "src/globals.h"
12 : #include "src/handles.h"
13 : #include "src/objects.h"
14 : #include "src/ostreams.h"
15 :
16 : namespace v8 {
17 : namespace internal {
18 : namespace compiler {
19 :
20 : // SUMMARY
21 : //
22 : // A simple type system for compiler-internal use. It is based entirely on
23 : // union types, and all subtyping hence amounts to set inclusion. Besides the
24 : // obvious primitive types and some predefined unions, the type language also
25 : // can express class types (a.k.a. specific maps) and singleton types (i.e.,
26 : // concrete constants).
27 : //
28 : // The following equations and inequations hold:
29 : //
30 : // None <= T
31 : // T <= Any
32 : //
33 : // Number = Signed32 \/ Unsigned32 \/ Double
34 : // Smi <= Signed32
35 : // Name = String \/ Symbol
36 : // UniqueName = InternalizedString \/ Symbol
37 : // InternalizedString < String
38 : //
39 : // Receiver = Object \/ Proxy
40 : // OtherUndetectable < Object
41 : // DetectableReceiver = Receiver - OtherUndetectable
42 : //
43 : // Constant(x) < T iff instance_type(map(x)) < T
44 : //
45 : //
46 : // RANGE TYPES
47 : //
48 : // A range type represents a continuous integer interval by its minimum and
49 : // maximum value. Either value may be an infinity, in which case that infinity
50 : // itself is also included in the range. A range never contains NaN or -0.
51 : //
52 : // If a value v happens to be an integer n, then Constant(v) is considered a
53 : // subtype of Range(n, n) (and therefore also a subtype of any larger range).
54 : // In order to avoid large unions, however, it is usually a good idea to use
55 : // Range rather than Constant.
56 : //
57 : //
58 : // PREDICATES
59 : //
60 : // There are two main functions for testing types:
61 : //
62 : // T1.Is(T2) -- tests whether T1 is included in T2 (i.e., T1 <= T2)
63 : // T1.Maybe(T2) -- tests whether T1 and T2 overlap (i.e., T1 /\ T2 =/= 0)
64 : //
65 : // Typically, the former is to be used to select representations (e.g., via
66 : // T.Is(SignedSmall())), and the latter to check whether a specific case needs
67 : // handling (e.g., via T.Maybe(Number())).
68 : //
69 : // There is no functionality to discover whether a type is a leaf in the
70 : // lattice. That is intentional. It should always be possible to refine the
71 : // lattice (e.g., splitting up number types further) without invalidating any
72 : // existing assumptions or tests.
73 : // Consequently, do not normally use Equals for type tests, always use Is!
74 : //
75 : // The NowIs operator implements state-sensitive subtying, as described above.
76 : // Any compilation decision based on such temporary properties requires runtime
77 : // guarding!
78 : //
79 : //
80 : // PROPERTIES
81 : //
82 : // Various formal properties hold for constructors, operators, and predicates
83 : // over types. For example, constructors are injective and subtyping is a
84 : // complete partial order.
85 : //
86 : // See test/cctest/test-types.cc for a comprehensive executable specification,
87 : // especially with respect to the properties of the more exotic 'temporal'
88 : // constructors and predicates (those prefixed 'Now').
89 : //
90 : //
91 : // IMPLEMENTATION
92 : //
93 : // Internally, all 'primitive' types, and their unions, are represented as
94 : // bitsets. Bit 0 is reserved for tagging. Only structured types require
95 : // allocation.
96 :
97 : // -----------------------------------------------------------------------------
98 : // Values for bitset types
99 :
100 : // clang-format off
101 :
102 : #define INTERNAL_BITSET_TYPE_LIST(V) \
103 : V(OtherUnsigned31, 1u << 1) \
104 : V(OtherUnsigned32, 1u << 2) \
105 : V(OtherSigned32, 1u << 3) \
106 : V(OtherNumber, 1u << 4) \
107 : V(OtherString, 1u << 5) \
108 :
109 : #define PROPER_BITSET_TYPE_LIST(V) \
110 : V(None, 0u) \
111 : V(Negative31, 1u << 6) \
112 : V(Null, 1u << 7) \
113 : V(Undefined, 1u << 8) \
114 : V(Boolean, 1u << 9) \
115 : V(Unsigned30, 1u << 10) \
116 : V(MinusZero, 1u << 11) \
117 : V(NaN, 1u << 12) \
118 : V(Symbol, 1u << 13) \
119 : V(InternalizedString, 1u << 14) \
120 : V(OtherCallable, 1u << 16) \
121 : V(OtherObject, 1u << 17) \
122 : V(OtherUndetectable, 1u << 18) \
123 : V(CallableProxy, 1u << 19) \
124 : V(OtherProxy, 1u << 20) \
125 : V(Function, 1u << 21) \
126 : V(BoundFunction, 1u << 22) \
127 : V(Hole, 1u << 23) \
128 : V(OtherInternal, 1u << 24) \
129 : V(ExternalPointer, 1u << 25) \
130 : V(Array, 1u << 26) \
131 : V(BigInt, 1u << 27) \
132 : \
133 : V(Signed31, kUnsigned30 | kNegative31) \
134 : V(Signed32, kSigned31 | kOtherUnsigned31 | \
135 : kOtherSigned32) \
136 : V(Signed32OrMinusZero, kSigned32 | kMinusZero) \
137 : V(Signed32OrMinusZeroOrNaN, kSigned32 | kMinusZero | kNaN) \
138 : V(Negative32, kNegative31 | kOtherSigned32) \
139 : V(Unsigned31, kUnsigned30 | kOtherUnsigned31) \
140 : V(Unsigned32, kUnsigned30 | kOtherUnsigned31 | \
141 : kOtherUnsigned32) \
142 : V(Unsigned32OrMinusZero, kUnsigned32 | kMinusZero) \
143 : V(Unsigned32OrMinusZeroOrNaN, kUnsigned32 | kMinusZero | kNaN) \
144 : V(Integral32, kSigned32 | kUnsigned32) \
145 : V(Integral32OrMinusZero, kIntegral32 | kMinusZero) \
146 : V(Integral32OrMinusZeroOrNaN, kIntegral32OrMinusZero | kNaN) \
147 : V(PlainNumber, kIntegral32 | kOtherNumber) \
148 : V(OrderedNumber, kPlainNumber | kMinusZero) \
149 : V(MinusZeroOrNaN, kMinusZero | kNaN) \
150 : V(Number, kOrderedNumber | kNaN) \
151 : V(Numeric, kNumber | kBigInt) \
152 : V(String, kInternalizedString | kOtherString) \
153 : V(UniqueName, kSymbol | kInternalizedString) \
154 : V(Name, kSymbol | kString) \
155 : V(InternalizedStringOrNull, kInternalizedString | kNull) \
156 : V(BooleanOrNumber, kBoolean | kNumber) \
157 : V(BooleanOrNullOrNumber, kBooleanOrNumber | kNull) \
158 : V(BooleanOrNullOrUndefined, kBoolean | kNull | kUndefined) \
159 : V(Oddball, kBooleanOrNullOrUndefined | kHole) \
160 : V(NullOrNumber, kNull | kNumber) \
161 : V(NullOrUndefined, kNull | kUndefined) \
162 : V(Undetectable, kNullOrUndefined | kOtherUndetectable) \
163 : V(NumberOrHole, kNumber | kHole) \
164 : V(NumberOrOddball, kNumber | kNullOrUndefined | kBoolean | \
165 : kHole) \
166 : V(NumericOrString, kNumeric | kString) \
167 : V(NumberOrUndefined, kNumber | kUndefined) \
168 : V(NumberOrUndefinedOrNullOrBoolean, \
169 : kNumber | kNullOrUndefined | kBoolean) \
170 : V(PlainPrimitive, kNumber | kString | kBoolean | \
171 : kNullOrUndefined) \
172 : V(NonBigIntPrimitive, kSymbol | kPlainPrimitive) \
173 : V(Primitive, kBigInt | kNonBigIntPrimitive) \
174 : V(OtherUndetectableOrUndefined, kOtherUndetectable | kUndefined) \
175 : V(Proxy, kCallableProxy | kOtherProxy) \
176 : V(ArrayOrOtherObject, kArray | kOtherObject) \
177 : V(ArrayOrProxy, kArray | kProxy) \
178 : V(DetectableCallable, kFunction | kBoundFunction | \
179 : kOtherCallable | kCallableProxy) \
180 : V(Callable, kDetectableCallable | kOtherUndetectable) \
181 : V(NonCallable, kArray | kOtherObject | kOtherProxy) \
182 : V(NonCallableOrNull, kNonCallable | kNull) \
183 : V(DetectableObject, kArray | kFunction | kBoundFunction | \
184 : kOtherCallable | kOtherObject) \
185 : V(DetectableReceiver, kDetectableObject | kProxy) \
186 : V(DetectableReceiverOrNull, kDetectableReceiver | kNull) \
187 : V(Object, kDetectableObject | kOtherUndetectable) \
188 : V(Receiver, kObject | kProxy) \
189 : V(ReceiverOrUndefined, kReceiver | kUndefined) \
190 : V(ReceiverOrNullOrUndefined, kReceiver | kNull | kUndefined) \
191 : V(SymbolOrReceiver, kSymbol | kReceiver) \
192 : V(StringOrReceiver, kString | kReceiver) \
193 : V(Unique, kBoolean | kUniqueName | kNull | \
194 : kUndefined | kReceiver) \
195 : V(Internal, kHole | kExternalPointer | kOtherInternal) \
196 : V(NonInternal, kPrimitive | kReceiver) \
197 : V(NonBigInt, kNonBigIntPrimitive | kReceiver) \
198 : V(NonNumber, kBigInt | kUnique | kString | kInternal) \
199 : V(Any, 0xfffffffeu)
200 :
201 : // clang-format on
202 :
203 : /*
204 : * The following diagrams show how integers (in the mathematical sense) are
205 : * divided among the different atomic numerical types.
206 : *
207 : * ON OS32 N31 U30 OU31 OU32 ON
208 : * ______[_______[_______[_______[_______[_______[_______
209 : * -2^31 -2^30 0 2^30 2^31 2^32
210 : *
211 : * E.g., OtherUnsigned32 (OU32) covers all integers from 2^31 to 2^32-1.
212 : *
213 : * Some of the atomic numerical bitsets are internal only (see
214 : * INTERNAL_BITSET_TYPE_LIST). To a types user, they should only occur in
215 : * union with certain other bitsets. For instance, OtherNumber should only
216 : * occur as part of PlainNumber.
217 : */
218 :
219 : #define BITSET_TYPE_LIST(V) \
220 : INTERNAL_BITSET_TYPE_LIST(V) \
221 : PROPER_BITSET_TYPE_LIST(V)
222 :
223 : class HeapConstantType;
224 : class OtherNumberConstantType;
225 : class TupleType;
226 : class Type;
227 : class UnionType;
228 :
229 : // -----------------------------------------------------------------------------
230 : // Bitset types (internal).
231 :
232 : class V8_EXPORT_PRIVATE BitsetType {
233 : public:
234 : using bitset = uint32_t; // Internal
235 :
236 : enum : uint32_t {
237 : #define DECLARE_TYPE(type, value) k##type = (value),
238 : BITSET_TYPE_LIST(DECLARE_TYPE)
239 : #undef DECLARE_TYPE
240 : kUnusedEOL = 0
241 : };
242 :
243 : static bitset SignedSmall();
244 : static bitset UnsignedSmall();
245 :
246 : static bool IsNone(bitset bits) { return bits == kNone; }
247 :
248 : static bool Is(bitset bits1, bitset bits2) {
249 353731398 : return (bits1 | bits2) == bits2;
250 : }
251 :
252 : static double Min(bitset);
253 : static double Max(bitset);
254 :
255 : static bitset Glb(double min, double max);
256 : static bitset Lub(HeapObjectType const& type) {
257 18989893 : return Lub<HeapObjectType>(type);
258 : }
259 12193 : static bitset Lub(MapRef const& map) { return Lub<MapRef>(map); }
260 : static bitset Lub(double value);
261 : static bitset Lub(double min, double max);
262 : static bitset ExpandInternals(bitset bits);
263 :
264 : static const char* Name(bitset);
265 : static void Print(std::ostream& os, bitset); // NOLINT
266 : #ifdef DEBUG
267 : static void Print(bitset);
268 : #endif
269 :
270 : static bitset NumberBits(bitset bits);
271 :
272 : private:
273 : struct Boundary {
274 : bitset internal;
275 : bitset external;
276 : double min;
277 : };
278 : static const Boundary BoundariesArray[];
279 : static inline const Boundary* Boundaries();
280 : static inline size_t BoundariesSize();
281 :
282 : template <typename MapRefLike>
283 : static bitset Lub(MapRefLike const& map);
284 : };
285 :
286 : // -----------------------------------------------------------------------------
287 : // Superclass for non-bitset types (internal).
288 : class TypeBase {
289 : protected:
290 : friend class Type;
291 :
292 : enum Kind { kHeapConstant, kOtherNumberConstant, kTuple, kUnion, kRange };
293 :
294 1151431675 : Kind kind() const { return kind_; }
295 63590230 : explicit TypeBase(Kind kind) : kind_(kind) {}
296 :
297 : static bool IsKind(Type type, Kind kind);
298 :
299 : private:
300 : Kind kind_;
301 : };
302 :
303 : // -----------------------------------------------------------------------------
304 : // Range types.
305 :
306 : class RangeType : public TypeBase {
307 : public:
308 : struct Limits {
309 : double min;
310 : double max;
311 17767148 : Limits(double min, double max) : min(min), max(max) {}
312 : explicit Limits(const RangeType* range)
313 : : min(range->Min()), max(range->Max()) {}
314 : bool IsEmpty();
315 : static Limits Empty() { return Limits(1, 0); }
316 : static Limits Intersect(Limits lhs, Limits rhs);
317 : static Limits Union(Limits lhs, Limits rhs);
318 : };
319 :
320 : double Min() const { return limits_.min; }
321 : double Max() const { return limits_.max; }
322 :
323 : static bool IsInteger(double x) {
324 9811803 : return nearbyint(x) == x && !IsMinusZero(x); // Allows for infinities.
325 : }
326 :
327 : private:
328 : friend class Type;
329 : friend class BitsetType;
330 : friend class UnionType;
331 :
332 : static RangeType* New(double min, double max, Zone* zone) {
333 17767148 : return New(Limits(min, max), zone);
334 : }
335 :
336 21657020 : static RangeType* New(Limits lim, Zone* zone) {
337 : DCHECK(IsInteger(lim.min) && IsInteger(lim.max));
338 : DCHECK(lim.min <= lim.max);
339 : BitsetType::bitset bits = BitsetType::Lub(lim.min, lim.max);
340 :
341 43313982 : return new (zone->New(sizeof(RangeType))) RangeType(bits, lim);
342 : }
343 :
344 : RangeType(BitsetType::bitset bitset, Limits limits)
345 21656991 : : TypeBase(kRange), bitset_(bitset), limits_(limits) {}
346 :
347 : BitsetType::bitset Lub() const { return bitset_; }
348 :
349 : BitsetType::bitset bitset_;
350 : Limits limits_;
351 : };
352 :
353 : // -----------------------------------------------------------------------------
354 : // The actual type.
355 :
356 : class V8_EXPORT_PRIVATE Type {
357 : public:
358 : using bitset = BitsetType::bitset; // Internal
359 :
360 : // Constructors.
361 : #define DEFINE_TYPE_CONSTRUCTOR(type, value) \
362 : static Type type() { return NewBitset(BitsetType::k##type); }
363 : PROPER_BITSET_TYPE_LIST(DEFINE_TYPE_CONSTRUCTOR)
364 : #undef DEFINE_TYPE_CONSTRUCTOR
365 :
366 201490984 : Type() : payload_(0) {}
367 :
368 6849140 : static Type SignedSmall() { return NewBitset(BitsetType::SignedSmall()); }
369 233109 : static Type UnsignedSmall() { return NewBitset(BitsetType::UnsignedSmall()); }
370 :
371 : static Type OtherNumberConstant(double value, Zone* zone);
372 : static Type HeapConstant(JSHeapBroker* broker, Handle<i::Object> value,
373 : Zone* zone);
374 : static Type HeapConstant(const HeapObjectRef& value, Zone* zone);
375 : static Type Range(double min, double max, Zone* zone);
376 : static Type Range(RangeType::Limits lims, Zone* zone);
377 : static Type Tuple(Type first, Type second, Type third, Zone* zone);
378 : static Type Union(int length, Zone* zone);
379 :
380 : // NewConstant is a factory that returns Constant, Range or Number.
381 : static Type NewConstant(JSHeapBroker* broker, Handle<i::Object> value,
382 : Zone* zone);
383 : static Type NewConstant(double value, Zone* zone);
384 :
385 : static Type Union(Type type1, Type type2, Zone* zone);
386 : static Type Intersect(Type type1, Type type2, Zone* zone);
387 :
388 : static Type For(HeapObjectType const& type) {
389 : return NewBitset(BitsetType::ExpandInternals(BitsetType::Lub(type)));
390 : }
391 12193 : static Type For(MapRef const& type) {
392 24386 : return NewBitset(BitsetType::ExpandInternals(BitsetType::Lub(type)));
393 : }
394 :
395 : // Predicates.
396 840599712 : bool IsNone() const { return payload_ == None().payload_; }
397 391239 : bool IsInvalid() const { return payload_ == 0u; }
398 :
399 46810532 : bool Is(Type that) const {
400 412798747 : return payload_ == that.payload_ || this->SlowIs(that);
401 : }
402 : bool Maybe(Type that) const;
403 344670 : bool Equals(Type that) const { return this->Is(that) && that.Is(*this); }
404 :
405 : // Inspection.
406 1455281434 : bool IsBitset() const { return payload_ & 1; }
407 : bool IsRange() const { return IsKind(TypeBase::kRange); }
408 : bool IsHeapConstant() const { return IsKind(TypeBase::kHeapConstant); }
409 : bool IsOtherNumberConstant() const {
410 : return IsKind(TypeBase::kOtherNumberConstant);
411 : }
412 : bool IsTuple() const { return IsKind(TypeBase::kTuple); }
413 :
414 : const HeapConstantType* AsHeapConstant() const;
415 : const OtherNumberConstantType* AsOtherNumberConstant() const;
416 : const RangeType* AsRange() const;
417 : const TupleType* AsTuple() const;
418 :
419 : // Minimum and maximum of a numeric type.
420 : // These functions do not distinguish between -0 and +0. NaN is ignored.
421 : // Only call them on subtypes of Number whose intersection with OrderedNumber
422 : // is not empty.
423 : double Min() const;
424 : double Max() const;
425 :
426 : // Extracts a range from the type: if the type is a range or a union
427 : // containing a range, that range is returned; otherwise, nullptr is returned.
428 : Type GetRange() const;
429 :
430 : int NumConstants() const;
431 :
432 : static Type Invalid() { return Type(); }
433 :
434 3020 : bool operator==(Type other) const { return payload_ == other.payload_; }
435 : bool operator!=(Type other) const { return payload_ != other.payload_; }
436 :
437 : // Printing.
438 :
439 : void PrintTo(std::ostream& os) const;
440 :
441 : #ifdef DEBUG
442 : void Print() const;
443 : #endif
444 :
445 : // Helpers for testing.
446 : bool IsUnionForTesting() { return IsUnion(); }
447 : bitset AsBitsetForTesting() { return AsBitset(); }
448 2504 : const UnionType* AsUnionForTesting() { return AsUnion(); }
449 44044 : Type BitsetGlbForTesting() { return NewBitset(BitsetGlb()); }
450 44052 : Type BitsetLubForTesting() { return NewBitset(BitsetLub()); }
451 :
452 : private:
453 : // Friends.
454 : template <class>
455 : friend class Iterator;
456 : friend BitsetType;
457 : friend UnionType;
458 : friend size_t hash_value(Type type);
459 :
460 60136941 : explicit Type(bitset bits) : payload_(bits | 1u) {}
461 : Type(TypeBase* type_base) // NOLINT(runtime/explicit)
462 60014764 : : payload_(reinterpret_cast<uintptr_t>(type_base)) {}
463 :
464 : // Internal inspection.
465 : bool IsKind(TypeBase::Kind kind) const {
466 1235859764 : if (IsBitset()) return false;
467 : const TypeBase* base = ToTypeBase();
468 1151431675 : return base->kind() == kind;
469 : }
470 :
471 : const TypeBase* ToTypeBase() const {
472 1664418903 : return reinterpret_cast<TypeBase*>(payload_);
473 : }
474 : static Type FromTypeBase(TypeBase* type) { return Type(type); }
475 :
476 43748853 : bool IsAny() const { return payload_ == Any().payload_; }
477 : bool IsUnion() const { return IsKind(TypeBase::kUnion); }
478 :
479 : bitset AsBitset() const {
480 : DCHECK(IsBitset());
481 647853511 : return static_cast<bitset>(payload_) ^ 1u;
482 : }
483 :
484 : const UnionType* AsUnion() const;
485 :
486 : bitset BitsetGlb() const; // greatest lower bound that's a bitset
487 : bitset BitsetLub() const; // least upper bound that's a bitset
488 :
489 : bool SlowIs(Type that) const;
490 :
491 : static Type NewBitset(bitset bits) { return Type(bits); }
492 :
493 : static bool Overlap(const RangeType* lhs, const RangeType* rhs);
494 : static bool Contains(const RangeType* lhs, const RangeType* rhs);
495 :
496 : static int UpdateRange(Type type, UnionType* result, int size, Zone* zone);
497 :
498 : static RangeType::Limits IntersectRangeAndBitset(Type range, Type bits,
499 : Zone* zone);
500 : static RangeType::Limits ToLimits(bitset bits, Zone* zone);
501 :
502 : bool SimplyEquals(Type that) const;
503 :
504 : static int AddToUnion(Type type, UnionType* result, int size, Zone* zone);
505 : static int IntersectAux(Type type, Type other, UnionType* result, int size,
506 : RangeType::Limits* limits, Zone* zone);
507 : static Type NormalizeUnion(UnionType* unioned, int size, Zone* zone);
508 : static Type NormalizeRangeAndBitset(Type range, bitset* bits, Zone* zone);
509 :
510 : // If LSB is set, the payload is a bitset; if LSB is clear, the payload is
511 : // a pointer to a subtype of the TypeBase class.
512 : uintptr_t payload_;
513 : };
514 :
515 : inline size_t hash_value(Type type) { return type.payload_; }
516 : V8_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& os, Type type);
517 :
518 : // -----------------------------------------------------------------------------
519 : // Constant types.
520 :
521 : class OtherNumberConstantType : public TypeBase {
522 : public:
523 : double Value() const { return value_; }
524 :
525 : static bool IsOtherNumberConstant(double value);
526 :
527 : private:
528 : friend class Type;
529 : friend class BitsetType;
530 :
531 1735499 : static OtherNumberConstantType* New(double value, Zone* zone) {
532 : return new (zone->New(sizeof(OtherNumberConstantType)))
533 1735499 : OtherNumberConstantType(value); // NOLINT
534 : }
535 :
536 1735499 : explicit OtherNumberConstantType(double value)
537 1735499 : : TypeBase(kOtherNumberConstant), value_(value) {
538 1735499 : CHECK(IsOtherNumberConstant(value));
539 1735499 : }
540 :
541 : BitsetType::bitset Lub() const { return BitsetType::kOtherNumber; }
542 :
543 : double value_;
544 : };
545 :
546 : class V8_EXPORT_PRIVATE HeapConstantType : public NON_EXPORTED_BASE(TypeBase) {
547 : public:
548 : Handle<HeapObject> Value() const;
549 : const HeapObjectRef& Ref() const { return heap_ref_; }
550 :
551 : private:
552 : friend class Type;
553 : friend class BitsetType;
554 :
555 18989884 : static HeapConstantType* New(const HeapObjectRef& heap_ref, Zone* zone) {
556 : DCHECK(!heap_ref.IsHeapNumber());
557 : DCHECK_IMPLIES(heap_ref.IsString(), heap_ref.IsInternalizedString());
558 37979760 : BitsetType::bitset bitset = BitsetType::Lub(heap_ref.GetHeapObjectType());
559 : return new (zone->New(sizeof(HeapConstantType)))
560 37979730 : HeapConstantType(bitset, heap_ref);
561 : }
562 :
563 : HeapConstantType(BitsetType::bitset bitset, const HeapObjectRef& heap_ref);
564 :
565 : BitsetType::bitset Lub() const { return bitset_; }
566 :
567 : BitsetType::bitset bitset_;
568 : HeapObjectRef heap_ref_;
569 : };
570 :
571 : // -----------------------------------------------------------------------------
572 : // Superclass for types with variable number of type fields.
573 : class StructuralType : public TypeBase {
574 : public:
575 : int LengthForTesting() const { return Length(); }
576 :
577 : protected:
578 : friend class Type;
579 :
580 : int Length() const { return length_; }
581 :
582 : Type Get(int i) const {
583 : DCHECK(0 <= i && i < this->Length());
584 261153377 : return elements_[i];
585 : }
586 :
587 : void Set(int i, Type type) {
588 : DCHECK(0 <= i && i < this->Length());
589 56283339 : elements_[i] = type;
590 : }
591 :
592 : void Shrink(int length) {
593 : DCHECK(2 <= length && length <= this->Length());
594 17629694 : length_ = length;
595 : }
596 :
597 : StructuralType(Kind kind, int length, Zone* zone)
598 21207875 : : TypeBase(kind), length_(length) {
599 21207875 : elements_ = reinterpret_cast<Type*>(zone->New(sizeof(Type) * length));
600 : }
601 :
602 : private:
603 : int length_;
604 : Type* elements_;
605 : };
606 :
607 : // -----------------------------------------------------------------------------
608 : // Tuple types.
609 :
610 : class TupleType : public StructuralType {
611 : public:
612 : int Arity() const { return this->Length(); }
613 : Type Element(int i) const { return this->Get(i); }
614 :
615 : void InitElement(int i, Type type) { this->Set(i, type); }
616 :
617 : private:
618 : friend class Type;
619 :
620 : TupleType(int length, Zone* zone) : StructuralType(kTuple, length, zone) {}
621 :
622 1380 : static TupleType* New(int length, Zone* zone) {
623 2760 : return new (zone->New(sizeof(TupleType))) TupleType(length, zone);
624 : }
625 : };
626 :
627 : // -----------------------------------------------------------------------------
628 : // Union types (internal).
629 : // A union is a structured type with the following invariants:
630 : // - its length is at least 2
631 : // - at most one field is a bitset, and it must go into index 0
632 : // - no field is a union
633 : // - no field is a subtype of any other field
634 : class UnionType : public StructuralType {
635 : private:
636 : friend Type;
637 : friend BitsetType;
638 :
639 : UnionType(int length, Zone* zone) : StructuralType(kUnion, length, zone) {}
640 :
641 21206504 : static UnionType* New(int length, Zone* zone) {
642 42412966 : return new (zone->New(sizeof(UnionType))) UnionType(length, zone);
643 : }
644 :
645 : bool Wellformed() const;
646 : };
647 :
648 : } // namespace compiler
649 : } // namespace internal
650 : } // namespace v8
651 :
652 : #endif // V8_COMPILER_TYPES_H_
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