1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
|
//===-- vector.h ------------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef SCUDO_VECTOR_H_
#define SCUDO_VECTOR_H_
#include "common.h"
#include <string.h>
namespace scudo {
// A low-level vector based on map. May incur a significant memory overhead for
// small vectors. The current implementation supports only POD types.
template <typename T> class VectorNoCtor {
public:
constexpr void init(uptr InitialCapacity = 0) {
Data = &LocalData[0];
CapacityBytes = sizeof(LocalData);
if (InitialCapacity > capacity())
reserve(InitialCapacity);
}
void destroy() {
if (Data != &LocalData[0])
unmap(Data, CapacityBytes);
}
T &operator[](uptr I) {
DCHECK_LT(I, Size);
return Data[I];
}
const T &operator[](uptr I) const {
DCHECK_LT(I, Size);
return Data[I];
}
void push_back(const T &Element) {
DCHECK_LE(Size, capacity());
if (Size == capacity()) {
const uptr NewCapacity = roundUpToPowerOfTwo(Size + 1);
reallocate(NewCapacity);
}
memcpy(&Data[Size++], &Element, sizeof(T));
}
T &back() {
DCHECK_GT(Size, 0);
return Data[Size - 1];
}
void pop_back() {
DCHECK_GT(Size, 0);
Size--;
}
uptr size() const { return Size; }
const T *data() const { return Data; }
T *data() { return Data; }
constexpr uptr capacity() const { return CapacityBytes / sizeof(T); }
void reserve(uptr NewSize) {
// Never downsize internal buffer.
if (NewSize > capacity())
reallocate(NewSize);
}
void resize(uptr NewSize) {
if (NewSize > Size) {
reserve(NewSize);
memset(&Data[Size], 0, sizeof(T) * (NewSize - Size));
}
Size = NewSize;
}
void clear() { Size = 0; }
bool empty() const { return size() == 0; }
const T *begin() const { return data(); }
T *begin() { return data(); }
const T *end() const { return data() + size(); }
T *end() { return data() + size(); }
private:
void reallocate(uptr NewCapacity) {
DCHECK_GT(NewCapacity, 0);
DCHECK_LE(Size, NewCapacity);
NewCapacity = roundUpTo(NewCapacity * sizeof(T), getPageSizeCached());
T *NewData =
reinterpret_cast<T *>(map(nullptr, NewCapacity, "scudo:vector"));
memcpy(NewData, Data, Size * sizeof(T));
destroy();
Data = NewData;
CapacityBytes = NewCapacity;
}
T *Data = nullptr;
T LocalData[256 / sizeof(T)] = {};
uptr CapacityBytes = 0;
uptr Size = 0;
};
template <typename T> class Vector : public VectorNoCtor<T> {
public:
constexpr Vector() { VectorNoCtor<T>::init(); }
explicit Vector(uptr Count) {
VectorNoCtor<T>::init(Count);
this->resize(Count);
}
~Vector() { VectorNoCtor<T>::destroy(); }
// Disallow copies and moves.
Vector(const Vector &) = delete;
Vector &operator=(const Vector &) = delete;
Vector(Vector &&) = delete;
Vector &operator=(Vector &&) = delete;
};
} // namespace scudo
#endif // SCUDO_VECTOR_H_
|
