v8  3.14.5(node0.10.28)
V8 is Google's open source JavaScript engine
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Pages
small-pointer-list.h
Go to the documentation of this file.
1 // Copyright 2011 the V8 project authors. All rights reserved.
2 // Redistribution and use in source and binary forms, with or without
3 // modification, are permitted provided that the following conditions are
4 // met:
5 //
6 // * Redistributions of source code must retain the above copyright
7 // notice, this list of conditions and the following disclaimer.
8 // * Redistributions in binary form must reproduce the above
9 // copyright notice, this list of conditions and the following
10 // disclaimer in the documentation and/or other materials provided
11 // with the distribution.
12 // * Neither the name of Google Inc. nor the names of its
13 // contributors may be used to endorse or promote products derived
14 // from this software without specific prior written permission.
15 //
16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 
28 #ifndef V8_SMALL_POINTER_LIST_H_
29 #define V8_SMALL_POINTER_LIST_H_
30 
31 #include "checks.h"
32 #include "v8globals.h"
33 #include "zone.h"
34 
35 namespace v8 {
36 namespace internal {
37 
38 // SmallPointerList is a list optimized for storing no or just a
39 // single value. When more values are given it falls back to ZoneList.
40 //
41 // The interface tries to be as close to List from list.h as possible.
42 template <typename T>
44  public:
45  SmallPointerList() : data_(kEmptyTag) {}
46 
47  SmallPointerList(int capacity, Zone* zone) : data_(kEmptyTag) {
48  Reserve(capacity, zone);
49  }
50 
51  void Reserve(int capacity, Zone* zone) {
52  if (capacity < 2) return;
53  if ((data_ & kTagMask) == kListTag) {
54  if (list()->capacity() >= capacity) return;
55  int old_length = list()->length();
56  list()->AddBlock(NULL, capacity - list()->capacity(), zone);
57  list()->Rewind(old_length);
58  return;
59  }
60  PointerList* list = new(zone) PointerList(capacity, zone);
61  if ((data_ & kTagMask) == kSingletonTag) {
62  list->Add(single_value(), zone);
63  }
64  ASSERT(IsAligned(reinterpret_cast<intptr_t>(list), kPointerAlignment));
65  data_ = reinterpret_cast<intptr_t>(list) | kListTag;
66  }
67 
68  void Clear() {
69  data_ = kEmptyTag;
70  }
71 
72  void Sort() {
73  if ((data_ & kTagMask) == kListTag) {
74  list()->Sort(compare_value);
75  }
76  }
77 
78  bool is_empty() const { return length() == 0; }
79 
80  int length() const {
81  if ((data_ & kTagMask) == kEmptyTag) return 0;
82  if ((data_ & kTagMask) == kSingletonTag) return 1;
83  return list()->length();
84  }
85 
86  void Add(T* pointer, Zone* zone) {
87  ASSERT(IsAligned(reinterpret_cast<intptr_t>(pointer), kPointerAlignment));
88  if ((data_ & kTagMask) == kEmptyTag) {
89  data_ = reinterpret_cast<intptr_t>(pointer) | kSingletonTag;
90  return;
91  }
92  if ((data_ & kTagMask) == kSingletonTag) {
93  PointerList* list = new(zone) PointerList(2, zone);
94  list->Add(single_value(), zone);
95  list->Add(pointer, zone);
96  ASSERT(IsAligned(reinterpret_cast<intptr_t>(list), kPointerAlignment));
97  data_ = reinterpret_cast<intptr_t>(list) | kListTag;
98  return;
99  }
100  list()->Add(pointer, zone);
101  }
102 
103  // Note: returns T* and not T*& (unlike List from list.h).
104  // This makes the implementation simpler and more const correct.
105  T* at(int i) const {
106  ASSERT((data_ & kTagMask) != kEmptyTag);
107  if ((data_ & kTagMask) == kSingletonTag) {
108  ASSERT(i == 0);
109  return single_value();
110  }
111  return list()->at(i);
112  }
113 
114  // See the note above.
115  T* operator[](int i) const { return at(i); }
116 
117  // Remove the given element from the list (if present).
118  void RemoveElement(T* pointer) {
119  if ((data_ & kTagMask) == kEmptyTag) return;
120  if ((data_ & kTagMask) == kSingletonTag) {
121  if (pointer == single_value()) {
122  data_ = kEmptyTag;
123  }
124  return;
125  }
126  list()->RemoveElement(pointer);
127  }
128 
130  ASSERT((data_ & kTagMask) != kEmptyTag);
131  if ((data_ & kTagMask) == kSingletonTag) {
132  T* result = single_value();
133  data_ = kEmptyTag;
134  return result;
135  }
136  return list()->RemoveLast();
137  }
138 
139  void Rewind(int pos) {
140  if ((data_ & kTagMask) == kEmptyTag) {
141  ASSERT(pos == 0);
142  return;
143  }
144  if ((data_ & kTagMask) == kSingletonTag) {
145  ASSERT(pos == 0 || pos == 1);
146  if (pos == 0) {
147  data_ = kEmptyTag;
148  }
149  return;
150  }
151  list()->Rewind(pos);
152  }
153 
154  int CountOccurrences(T* pointer, int start, int end) const {
155  if ((data_ & kTagMask) == kEmptyTag) return 0;
156  if ((data_ & kTagMask) == kSingletonTag) {
157  if (start == 0 && end >= 0) {
158  return (single_value() == pointer) ? 1 : 0;
159  }
160  return 0;
161  }
162  return list()->CountOccurrences(pointer, start, end);
163  }
164 
165  private:
166  typedef ZoneList<T*> PointerList;
167 
168  static int compare_value(T* const* a, T* const* b) {
169  return Compare<T>(**a, **b);
170  }
171 
172  static const intptr_t kEmptyTag = 1;
173  static const intptr_t kSingletonTag = 0;
174  static const intptr_t kListTag = 2;
175  static const intptr_t kTagMask = 3;
176  static const intptr_t kValueMask = ~kTagMask;
177 
178  STATIC_ASSERT(kTagMask + 1 <= kPointerAlignment);
179 
180  T* single_value() const {
181  ASSERT((data_ & kTagMask) == kSingletonTag);
182  STATIC_ASSERT(kSingletonTag == 0);
183  return reinterpret_cast<T*>(data_);
184  }
185 
186  PointerList* list() const {
187  ASSERT((data_ & kTagMask) == kListTag);
188  return reinterpret_cast<PointerList*>(data_ & kValueMask);
189  }
190 
191  intptr_t data_;
192 
193  DISALLOW_COPY_AND_ASSIGN(SmallPointerList);
194 };
195 
196 } } // namespace v8::internal
197 
198 #endif // V8_SMALL_POINTER_LIST_H_
T & at(int i) const
Definition: list.h:90
SmallPointerList(int capacity, Zone *zone)
#define ASSERT(condition)
Definition: checks.h:270
bool IsAligned(T value, U alignment)
Definition: utils.h:206
int CountOccurrences(T *pointer, int start, int end) const
#define T(name, string, precedence)
Definition: token.cc:48
void Sort(int(*cmp)(const T *x, const T *y))
Definition: list-inl.h:198
int CountOccurrences(const T &elm, int start, int end) const
Definition: list-inl.h:188
const intptr_t kPointerAlignment
Definition: v8globals.h:48
void Reserve(int capacity, Zone *zone)
void Add(T *pointer, Zone *zone)
void Add(const T &element, AllocationPolicy allocator=AllocationPolicy())
Definition: list-inl.h:38
activate correct semantics for inheriting readonliness enable harmony semantics for typeof enable harmony enable harmony proxies enable all harmony harmony_scoping harmony_proxies harmony_scoping tracks arrays with only smi values automatically unbox arrays of doubles use crankshaft use hydrogen range analysis use hydrogen global value numbering use function inlining maximum number of AST nodes considered for a single inlining loop invariant code motion print statistics for hydrogen trace generated IR for specified phases trace register allocator trace range analysis trace representation types environment for every instruction put a break point before deoptimizing polymorphic inlining perform array bounds checks elimination use dead code elimination trace on stack replacement optimize closures cache optimized code for closures functions with arguments object loop weight for representation inference allow uint32 values on optimize frames if they are used only in safe operations track parallel recompilation enable all profiler experiments number of stack frames inspected by the profiler call recompile stub directly when self optimizing trigger profiler ticks based on counting instead of timing weight back edges by jump distance for interrupt triggering percentage of ICs that must have type info to allow optimization watch_ic_patching retry_self_opt interrupt_at_exit extra verbose compilation tracing generate extra emit comments in code disassembly enable use of SSE3 instructions if available enable use of CMOV instruction if available enable use of SAHF instruction if enable use of VFP3 instructions if available this implies enabling ARMv7 and VFP2 enable use of VFP2 instructions if available enable use of SDIV and UDIV instructions if enable loading bit constant by means of movw movt instruction enable unaligned accesses for enable use of MIPS FPU instructions if NULL
Definition: flags.cc:301
Vector< T > AddBlock(T value, int count, AllocationPolicy allocator=AllocationPolicy())
Definition: list-inl.h:97
bool RemoveElement(const T &elm)
Definition: list-inl.h:128