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Issue 142813003: A64: Synchronize with r15358. (Closed) Base URL: https://v8.googlecode.com/svn/branches/experimental/a64
Patch Set: Created 6 years, 11 months ago
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1 // Copyright 2012 the V8 project authors. All rights reserved. 1 // Copyright 2012 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
(...skipping 50 matching lines...) Expand 10 before | Expand all | Expand 10 after
61 Address address(int n) const { 61 Address address(int n) const {
62 return Address(this) + n; 62 return Address(this) + n;
63 } 63 }
64 64
65 Segment* next_; 65 Segment* next_;
66 int size_; 66 int size_;
67 }; 67 };
68 68
69 69
70 Zone::Zone(Isolate* isolate) 70 Zone::Zone(Isolate* isolate)
71 : zone_excess_limit_(256 * MB), 71 : allocation_size_(0),
72 allocation_size_(0),
73 segment_bytes_allocated_(0), 72 segment_bytes_allocated_(0),
74 position_(0), 73 position_(0),
75 limit_(0), 74 limit_(0),
76 scope_nesting_(0),
77 segment_head_(NULL), 75 segment_head_(NULL),
78 isolate_(isolate) { 76 isolate_(isolate) {
79 } 77 }
80 78
81 79
82 ZoneScope::~ZoneScope() { 80 Zone::~Zone() {
83 if (ShouldDeleteOnExit()) zone_->DeleteAll(); 81 #ifdef DEBUG
84 zone_->scope_nesting_--; 82 // Constant byte value used for zapping dead memory in debug mode.
83 static const unsigned char kZapDeadByte = 0xcd;
84 #endif
85
86 // Traverse the chained list of segments, zapping
87 // (in debug mode) and freeing every segment
88 Segment* current = segment_head_;
89 while (current != NULL) {
90 Segment* next = current->next();
91 int size = current->size();
92 #ifdef DEBUG
93 // Zap the entire current segment (including the header).
94 memset(current, kZapDeadByte, size);
95 #endif
96 DeleteSegment(current, size);
97 current = next;
98 }
99
100 // We must clear the position and limit to force
101 // a new segment to be allocated on demand.
102 position_ = limit_ = 0;
103
104 // Update the head segment.
105 segment_head_ = NULL;
85 } 106 }
86 107
87 108
88 // Creates a new segment, sets it size, and pushes it to the front 109 // Creates a new segment, sets it size, and pushes it to the front
89 // of the segment chain. Returns the new segment. 110 // of the segment chain. Returns the new segment.
90 Segment* Zone::NewSegment(int size) { 111 Segment* Zone::NewSegment(int size) {
91 Segment* result = reinterpret_cast<Segment*>(Malloced::New(size)); 112 Segment* result = reinterpret_cast<Segment*>(Malloced::New(size));
92 adjust_segment_bytes_allocated(size); 113 adjust_segment_bytes_allocated(size);
93 if (result != NULL) { 114 if (result != NULL) {
94 result->Initialize(segment_head_, size); 115 result->Initialize(segment_head_, size);
95 segment_head_ = result; 116 segment_head_ = result;
96 } 117 }
97 return result; 118 return result;
98 } 119 }
99 120
100 121
101 // Deletes the given segment. Does not touch the segment chain. 122 // Deletes the given segment. Does not touch the segment chain.
102 void Zone::DeleteSegment(Segment* segment, int size) { 123 void Zone::DeleteSegment(Segment* segment, int size) {
103 adjust_segment_bytes_allocated(-size); 124 adjust_segment_bytes_allocated(-size);
104 Malloced::Delete(segment); 125 Malloced::Delete(segment);
105 } 126 }
106 127
107 128
108 void Zone::DeleteAll() {
109 #ifdef DEBUG
110 // Constant byte value used for zapping dead memory in debug mode.
111 static const unsigned char kZapDeadByte = 0xcd;
112 #endif
113
114 // Find a segment with a suitable size to keep around.
115 Segment* keep = segment_head_;
116 while (keep != NULL && keep->size() > kMaximumKeptSegmentSize) {
117 keep = keep->next();
118 }
119
120 // Traverse the chained list of segments, zapping (in debug mode)
121 // and freeing every segment except the one we wish to keep.
122 Segment* current = segment_head_;
123 while (current != NULL) {
124 Segment* next = current->next();
125 if (current == keep) {
126 // Unlink the segment we wish to keep from the list.
127 current->clear_next();
128 } else {
129 int size = current->size();
130 #ifdef DEBUG
131 // Zap the entire current segment (including the header).
132 memset(current, kZapDeadByte, size);
133 #endif
134 DeleteSegment(current, size);
135 }
136 current = next;
137 }
138
139 // If we have found a segment we want to keep, we must recompute the
140 // variables 'position' and 'limit' to prepare for future allocate
141 // attempts. Otherwise, we must clear the position and limit to
142 // force a new segment to be allocated on demand.
143 if (keep != NULL) {
144 Address start = keep->start();
145 position_ = RoundUp(start, kAlignment);
146 limit_ = keep->end();
147 #ifdef DEBUG
148 // Zap the contents of the kept segment (but not the header).
149 memset(start, kZapDeadByte, keep->capacity());
150 #endif
151 } else {
152 position_ = limit_ = 0;
153 }
154
155 // Update the head segment to be the kept segment (if any).
156 segment_head_ = keep;
157 }
158
159
160 void Zone::DeleteKeptSegment() {
161 if (segment_head_ != NULL) {
162 DeleteSegment(segment_head_, segment_head_->size());
163 segment_head_ = NULL;
164 }
165 }
166
167
168 Address Zone::NewExpand(int size) { 129 Address Zone::NewExpand(int size) {
169 // Make sure the requested size is already properly aligned and that 130 // Make sure the requested size is already properly aligned and that
170 // there isn't enough room in the Zone to satisfy the request. 131 // there isn't enough room in the Zone to satisfy the request.
171 ASSERT(size == RoundDown(size, kAlignment)); 132 ASSERT(size == RoundDown(size, kAlignment));
172 ASSERT(size > limit_ - position_); 133 ASSERT(size > limit_ - position_);
173 134
174 // Compute the new segment size. We use a 'high water mark' 135 // Compute the new segment size. We use a 'high water mark'
175 // strategy, where we increase the segment size every time we expand 136 // strategy, where we increase the segment size every time we expand
176 // except that we employ a maximum segment size when we delete. This 137 // except that we employ a maximum segment size when we delete. This
177 // is to avoid excessive malloc() and free() overhead. 138 // is to avoid excessive malloc() and free() overhead.
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208 V8::FatalProcessOutOfMemory("Zone"); 169 V8::FatalProcessOutOfMemory("Zone");
209 return NULL; 170 return NULL;
210 } 171 }
211 limit_ = segment->end(); 172 limit_ = segment->end();
212 ASSERT(position_ <= limit_); 173 ASSERT(position_ <= limit_);
213 return result; 174 return result;
214 } 175 }
215 176
216 177
217 } } // namespace v8::internal 178 } } // namespace v8::internal
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