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1 // Copyright 2016 the V8 project authors. All rights reserved. | 1 // Copyright 2016 the V8 project authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef V8_ZONE_ZONE_SEGMENT_H_ | 5 #ifndef V8_ZONE_ZONE_SEGMENT_H_ |
6 #define V8_ZONE_ZONE_SEGMENT_H_ | 6 #define V8_ZONE_ZONE_SEGMENT_H_ |
7 | 7 |
8 #include "src/v8.h" | 8 #include "src/v8.h" |
9 | 9 |
10 // Segments represent chunks of memory: They have starting address | 10 // Segments represent chunks of memory: They have starting address |
11 // (encoded in the this pointer) and a size in bytes. Segments are | 11 // (encoded in the this pointer) and a size in bytes. Segments are |
12 // chained together forming a LIFO structure with the newest segment | 12 // chained together forming a LIFO structure with the newest segment |
13 // available as segment_head_. Segments are allocated using malloc() | 13 // available as segment_head_. Segments are allocated using malloc() |
14 // and de-allocated using free(). | 14 // and de-allocated using free(). |
15 namespace v8 { | 15 namespace v8 { |
16 namespace internal { | 16 namespace internal { |
17 | 17 |
18 // Forward declaration | 18 // Forward declaration |
19 class Zone; | 19 class Zone; |
20 | 20 |
21 class Segment { | 21 class Segment { |
22 public: | 22 public: |
23 void Initialize(size_t size) { size_ = size; } | 23 void Initialize(Segment* next, size_t size, Zone* zone) { |
| 24 next_ = next; |
| 25 size_ = size; |
| 26 zone_ = zone; |
| 27 } |
24 | 28 |
25 Zone* zone() const { return zone_; } | 29 Zone* zone() const { return zone_; } |
26 void set_zone(Zone* const zone) { zone_ = zone; } | 30 void set_zone(Zone* const zone) { zone_ = zone; } |
27 | 31 |
28 Segment* next() const { return next_; } | 32 Segment* next() const { return next_; } |
29 void set_next(Segment* const next) { next_ = next; } | 33 void set_next(Segment* const next) { next_ = next; } |
30 | 34 |
31 size_t size() const { return size_; } | 35 size_t size() const { return size_; } |
32 size_t capacity() const { return size_ - sizeof(Segment); } | 36 size_t capacity() const { return size_ - sizeof(Segment); } |
33 | 37 |
34 Address start() const { return address(sizeof(Segment)); } | 38 Address start() const { return address(sizeof(Segment)); } |
35 Address end() const { return address(size_); } | 39 Address end() const { return address(size_); } |
36 | 40 |
37 // Zap the contents of the segment (but not the header). | 41 // Zap the contents of the segment (but not the header). |
38 void ZapContents(); | 42 void ZapContents(); |
39 // Zaps the header and makes the segment unusable this way. | 43 // Zaps the header and makes the segment unusable this way. |
40 void ZapHeader(); | 44 void ZapHeader(); |
41 | 45 |
42 private: | 46 private: |
43 #ifdef DEBUG | 47 #ifdef DEBUG |
44 // Constant byte value used for zapping dead memory in debug mode. | 48 // Constant byte value used for zapping dead memory in debug mode. |
45 static const unsigned char kZapDeadByte = 0xcd; | 49 static const unsigned char kZapDeadByte = 0xcd; |
46 #endif | 50 #endif |
47 | |
48 // Computes the address of the nth byte in this segment. | 51 // Computes the address of the nth byte in this segment. |
49 Address address(size_t n) const { return Address(this) + n; } | 52 Address address(size_t n) const { return Address(this) + n; } |
50 | 53 |
51 Zone* zone_; | 54 Zone* zone_; |
52 Segment* next_; | 55 Segment* next_; |
53 size_t size_; | 56 size_t size_; |
54 }; | 57 }; |
55 } // namespace internal | 58 } // namespace internal |
56 } // namespace v8 | 59 } // namespace v8 |
57 | 60 |
58 #endif // V8_ZONE_ZONE_SEGMENT_H_ | 61 #endif // V8_ZONE_ZONE_SEGMENT_H_ |
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