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1 // Copyright 2013 the V8 project authors. All rights reserved. | 1 // Copyright 2013 the V8 project authors. All rights reserved. |
2 // Redistribution and use in source and binary forms, with or without | 2 // Redistribution and use in source and binary forms, with or without |
3 // modification, are permitted provided that the following conditions are | 3 // modification, are permitted provided that the following conditions are |
4 // met: | 4 // met: |
5 // | 5 // |
6 // * Redistributions of source code must retain the above copyright | 6 // * Redistributions of source code must retain the above copyright |
7 // notice, this list of conditions and the following disclaimer. | 7 // notice, this list of conditions and the following disclaimer. |
8 // * Redistributions in binary form must reproduce the above | 8 // * Redistributions in binary form must reproduce the above |
9 // copyright notice, this list of conditions and the following | 9 // copyright notice, this list of conditions and the following |
10 // disclaimer in the documentation and/or other materials provided | 10 // disclaimer in the documentation and/or other materials provided |
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41 // obvious primitive types and some predefined unions, the type language also | 41 // obvious primitive types and some predefined unions, the type language also |
42 // can express class types (a.k.a. specific maps) and singleton types (i.e., | 42 // can express class types (a.k.a. specific maps) and singleton types (i.e., |
43 // concrete constants). | 43 // concrete constants). |
44 // | 44 // |
45 // The following equations and inequations hold: | 45 // The following equations and inequations hold: |
46 // | 46 // |
47 // None <= T | 47 // None <= T |
48 // T <= Any | 48 // T <= Any |
49 // | 49 // |
50 // Oddball = Boolean \/ Null \/ Undefined | 50 // Oddball = Boolean \/ Null \/ Undefined |
51 // Number = Integer32 \/ Double | 51 // Number = Signed32 \/ Unsigned32 \/ Double |
52 // Integer31 < Integer32 | 52 // Smi <= Signed32 |
53 // Name = String \/ Symbol | 53 // Name = String \/ Symbol |
54 // UniqueName = InternalizedString \/ Symbol | 54 // UniqueName = InternalizedString \/ Symbol |
55 // InternalizedString < String | 55 // InternalizedString < String |
56 // | 56 // |
57 // Allocated = Receiver \/ Number \/ Name | 57 // Allocated = Receiver \/ Number \/ Name |
58 // Detectable = Allocated - Undetectable | 58 // Detectable = Allocated - Undetectable |
59 // Undetectable < Object | 59 // Undetectable < Object |
60 // Receiver = Object \/ Proxy | 60 // Receiver = Object \/ Proxy |
61 // Array < Object | 61 // Array < Object |
62 // Function < Object | 62 // Function < Object |
| 63 // RegExp < Object |
63 // | 64 // |
64 // Class(map) < T iff instance_type(map) < T | 65 // Class(map) < T iff instance_type(map) < T |
65 // Constant(x) < T iff instance_type(map(x)) < T | 66 // Constant(x) < T iff instance_type(map(x)) < T |
66 // | 67 // |
67 // Note that Constant(x) < Class(map(x)) does _not_ hold, since x's map can | 68 // Note that Constant(x) < Class(map(x)) does _not_ hold, since x's map can |
68 // change! (Its instance type cannot, however.) | 69 // change! (Its instance type cannot, however.) |
69 // TODO(rossberg): the latter is not currently true for proxies, because of fix, | 70 // TODO(rossberg): the latter is not currently true for proxies, because of fix, |
70 // but will hold once we implement direct proxies. | 71 // but will hold once we implement direct proxies. |
71 // | 72 // |
72 // There are two main functions for testing types: | 73 // There are two main functions for testing types: |
73 // | 74 // |
74 // T1->Is(T2) -- tests whether T1 is included in T2 (i.e., T1 <= T2) | 75 // T1->Is(T2) -- tests whether T1 is included in T2 (i.e., T1 <= T2) |
75 // T1->Maybe(T2) -- tests whether T1 and T2 overlap (i.e., T1 /\ T2 =/= 0) | 76 // T1->Maybe(T2) -- tests whether T1 and T2 overlap (i.e., T1 /\ T2 =/= 0) |
76 // | 77 // |
77 // Typically, the former is to be used to select representations (e.g., via | 78 // Typically, the former is to be used to select representations (e.g., via |
78 // T->Is(Integer31())), and the to check whether a specific case needs handling | 79 // T->Is(Integer31())), and the to check whether a specific case needs handling |
79 // (e.g., via T->Maybe(Number())). | 80 // (e.g., via T->Maybe(Number())). |
80 // | 81 // |
81 // There is no functionality to discover whether a type is a leaf in the | 82 // There is no functionality to discover whether a type is a leaf in the |
82 // lattice. That is intentional. It should always be possible to refine the | 83 // lattice. That is intentional. It should always be possible to refine the |
83 // lattice (e.g., splitting up number types further) without invalidating any | 84 // lattice (e.g., splitting up number types further) without invalidating any |
84 // existing assumptions or tests. | 85 // existing assumptions or tests. |
85 // | 86 // |
| 87 // Consequently, do not use pointer equality for type tests, always use Is! |
| 88 // |
86 // Internally, all 'primitive' types, and their unions, are represented as | 89 // Internally, all 'primitive' types, and their unions, are represented as |
87 // bitsets via smis. Class is a heap pointer to the respective map. Only | 90 // bitsets via smis. Class is a heap pointer to the respective map. Only |
88 // Constant's, or unions containing Class'es or Constant's, require allocation. | 91 // Constant's, or unions containing Class'es or Constant's, require allocation. |
89 // Note that the bitset representation is closed under both Union and Intersect. | 92 // Note that the bitset representation is closed under both Union and Intersect. |
90 // | 93 // |
91 // The type representation is heap-allocated, so cannot (currently) be used in | 94 // The type representation is heap-allocated, so cannot (currently) be used in |
92 // a parallel compilation context. | 95 // a parallel compilation context. |
93 | 96 |
94 class Type : public Object { | 97 class Type : public Object { |
95 public: | 98 public: |
96 static Type* None() { return from_bitset(kNone); } | 99 static Type* None() { return from_bitset(kNone); } |
97 static Type* Any() { return from_bitset(kAny); } | 100 static Type* Any() { return from_bitset(kAny); } |
98 static Type* Allocated() { return from_bitset(kAllocated); } | 101 static Type* Allocated() { return from_bitset(kAllocated); } |
99 static Type* Detectable() { return from_bitset(kDetectable); } | 102 static Type* Detectable() { return from_bitset(kDetectable); } |
100 | 103 |
101 static Type* Oddball() { return from_bitset(kOddball); } | 104 static Type* Oddball() { return from_bitset(kOddball); } |
102 static Type* Boolean() { return from_bitset(kBoolean); } | 105 static Type* Boolean() { return from_bitset(kBoolean); } |
103 static Type* Null() { return from_bitset(kNull); } | 106 static Type* Null() { return from_bitset(kNull); } |
104 static Type* Undefined() { return from_bitset(kUndefined); } | 107 static Type* Undefined() { return from_bitset(kUndefined); } |
105 | 108 |
106 static Type* Number() { return from_bitset(kNumber); } | 109 static Type* Number() { return from_bitset(kNumber); } |
107 static Type* Integer31() { return from_bitset(kInteger31); } | 110 static Type* Smi() { return from_bitset(kSmi); } |
108 static Type* Integer32() { return from_bitset(kInteger32); } | 111 static Type* Signed32() { return from_bitset(kSigned32); } |
| 112 static Type* Unsigned32() { return from_bitset(kUnsigned32); } |
109 static Type* Double() { return from_bitset(kDouble); } | 113 static Type* Double() { return from_bitset(kDouble); } |
| 114 static Type* NumberOrString() { return from_bitset(kNumberOrString); } |
110 | 115 |
111 static Type* Name() { return from_bitset(kName); } | 116 static Type* Name() { return from_bitset(kName); } |
112 static Type* UniqueName() { return from_bitset(kUniqueName); } | 117 static Type* UniqueName() { return from_bitset(kUniqueName); } |
113 static Type* String() { return from_bitset(kString); } | 118 static Type* String() { return from_bitset(kString); } |
114 static Type* InternalizedString() { return from_bitset(kInternalizedString); } | 119 static Type* InternalizedString() { return from_bitset(kInternalizedString); } |
115 static Type* Symbol() { return from_bitset(kSymbol); } | 120 static Type* Symbol() { return from_bitset(kSymbol); } |
116 | 121 |
117 static Type* Receiver() { return from_bitset(kReceiver); } | 122 static Type* Receiver() { return from_bitset(kReceiver); } |
118 static Type* Object() { return from_bitset(kObject); } | 123 static Type* Object() { return from_bitset(kObject); } |
119 static Type* Undetectable() { return from_bitset(kUndetectable); } | 124 static Type* Undetectable() { return from_bitset(kUndetectable); } |
120 static Type* Array() { return from_bitset(kArray); } | 125 static Type* Array() { return from_bitset(kArray); } |
121 static Type* Function() { return from_bitset(kFunction); } | 126 static Type* Function() { return from_bitset(kFunction); } |
| 127 static Type* RegExp() { return from_bitset(kRegExp); } |
122 static Type* Proxy() { return from_bitset(kProxy); } | 128 static Type* Proxy() { return from_bitset(kProxy); } |
123 | 129 |
124 static Type* Class(Handle<Map> map) { return from_handle(map); } | 130 static Type* Class(Handle<Map> map) { return from_handle(map); } |
125 static Type* Constant(Handle<HeapObject> value) { | 131 static Type* Constant(Handle<HeapObject> value) { |
126 return Constant(value, value->GetIsolate()); | 132 return Constant(value, value->GetIsolate()); |
127 } | 133 } |
128 static Type* Constant(Handle<v8::internal::Object> value, Isolate* isolate) { | 134 static Type* Constant(Handle<v8::internal::Object> value, Isolate* isolate) { |
129 return from_handle(isolate->factory()->NewBox(value)); | 135 return from_handle(isolate->factory()->NewBox(value)); |
130 } | 136 } |
131 | 137 |
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181 // A union is a fixed array containing types. Invariants: | 187 // A union is a fixed array containing types. Invariants: |
182 // - its length is at least 2 | 188 // - its length is at least 2 |
183 // - at most one field is a bitset, and it must go into index 0 | 189 // - at most one field is a bitset, and it must go into index 0 |
184 // - no field is a union | 190 // - no field is a union |
185 typedef FixedArray Unioned; | 191 typedef FixedArray Unioned; |
186 | 192 |
187 enum { | 193 enum { |
188 kNull = 1 << 0, | 194 kNull = 1 << 0, |
189 kUndefined = 1 << 1, | 195 kUndefined = 1 << 1, |
190 kBoolean = 1 << 2, | 196 kBoolean = 1 << 2, |
191 kInteger31 = 1 << 3, | 197 kSmi = 1 << 3, |
192 kOtherInteger = 1 << 4, | 198 kOtherSigned32 = 1 << 4, |
193 kDouble = 1 << 5, | 199 kUnsigned32 = 1 << 5, |
194 kSymbol = 1 << 6, | 200 kDouble = 1 << 6, |
195 kInternalizedString = 1 << 7, | 201 kSymbol = 1 << 7, |
196 kOtherString = 1 << 8, | 202 kInternalizedString = 1 << 8, |
197 kUndetectable = 1 << 9, | 203 kOtherString = 1 << 9, |
198 kArray = 1 << 10, | 204 kUndetectable = 1 << 10, |
199 kFunction = 1 << 11, | 205 kArray = 1 << 11, |
200 kOtherObject = 1 << 12, | 206 kFunction = 1 << 12, |
201 kProxy = 1 << 13, | 207 kRegExp = 1 << 13, |
| 208 kOtherObject = 1 << 14, |
| 209 kProxy = 1 << 15, |
202 | 210 |
203 kOddball = kBoolean | kNull | kUndefined, | 211 kOddball = kBoolean | kNull | kUndefined, |
204 kInteger32 = kInteger31 | kOtherInteger, | 212 kSigned32 = kSmi | kOtherSigned32, |
205 kNumber = kInteger32 | kDouble, | 213 kNumber = kSigned32 | kUnsigned32 | kDouble, |
206 kString = kInternalizedString | kOtherString, | 214 kString = kInternalizedString | kOtherString, |
207 kUniqueName = kSymbol | kInternalizedString, | 215 kUniqueName = kSymbol | kInternalizedString, |
208 kName = kSymbol | kString, | 216 kName = kSymbol | kString, |
209 kObject = kUndetectable | kArray | kFunction | kOtherObject, | 217 kNumberOrString = kNumber | kString, |
| 218 kObject = kUndetectable | kArray | kFunction | kRegExp | kOtherObject, |
210 kReceiver = kObject | kProxy, | 219 kReceiver = kObject | kProxy, |
211 kAllocated = kDouble | kName | kReceiver, | 220 kAllocated = kDouble | kName | kReceiver, |
212 kAny = kOddball | kNumber | kAllocated, | 221 kAny = kOddball | kNumber | kAllocated, |
213 kDetectable = kAllocated - kUndetectable, | 222 kDetectable = kAllocated - kUndetectable, |
214 kNone = 0 | 223 kNone = 0 |
215 }; | 224 }; |
216 | 225 |
217 bool is_bitset() { return this->IsSmi(); } | 226 bool is_bitset() { return this->IsSmi(); } |
218 bool is_class() { return this->IsMap(); } | 227 bool is_class() { return this->IsMap(); } |
219 bool is_constant() { return this->IsBox(); } | 228 bool is_constant() { return this->IsBox(); } |
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250 int GlbBitset(); // greatest lower bound that's a bitset | 259 int GlbBitset(); // greatest lower bound that's a bitset |
251 bool InUnion(Handle<Unioned> unioned, int current_size); | 260 bool InUnion(Handle<Unioned> unioned, int current_size); |
252 int ExtendUnion(Handle<Unioned> unioned, int current_size); | 261 int ExtendUnion(Handle<Unioned> unioned, int current_size); |
253 int ExtendIntersection( | 262 int ExtendIntersection( |
254 Handle<Unioned> unioned, Handle<Type> type, int current_size); | 263 Handle<Unioned> unioned, Handle<Type> type, int current_size); |
255 }; | 264 }; |
256 | 265 |
257 } } // namespace v8::internal | 266 } } // namespace v8::internal |
258 | 267 |
259 #endif // V8_TYPES_H_ | 268 #endif // V8_TYPES_H_ |
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