1 | // Copyright (c) 2006, Google Inc. |
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29 | |
30 | // contained_range_map-inl.h: Hierarchically-organized range map implementation. |
31 | // |
32 | // See contained_range_map.h for documentation. |
33 | // |
34 | // Author: Mark Mentovai |
35 | |
36 | #ifndef PROCESSOR_CONTAINED_RANGE_MAP_INL_H__ |
37 | #define PROCESSOR_CONTAINED_RANGE_MAP_INL_H__ |
38 | |
39 | #include "processor/contained_range_map.h" |
40 | |
41 | #include <assert.h> |
42 | |
43 | #include "processor/logging.h" |
44 | |
45 | |
46 | namespace google_breakpad { |
47 | |
48 | |
49 | template<typename AddressType, typename EntryType> |
50 | ContainedRangeMap<AddressType, EntryType>::~ContainedRangeMap() { |
51 | // Clear frees the children pointed to by the map, and frees the map itself. |
52 | Clear(); |
53 | } |
54 | |
55 | |
56 | template<typename AddressType, typename EntryType> |
57 | bool ContainedRangeMap<AddressType, EntryType>::StoreRange( |
58 | const AddressType& base, const AddressType& size, const EntryType& entry) { |
59 | AddressType high = base + size - 1; |
60 | |
61 | // Check for undersize or overflow. |
62 | if (size <= 0 || high < base) { |
63 | //TODO(nealsid) We are commenting this out in order to prevent |
64 | // excessive logging. We plan to move to better logging as this |
65 | // failure happens quite often and is expected(see comment in |
66 | // basic_source_line_resolver.cc:671). |
67 | // BPLOG(INFO) << "StoreRange failed, " << HexString(base) << "+" |
68 | // << HexString(size) << ", " << HexString(high); |
69 | return false; |
70 | } |
71 | |
72 | if (!map_) |
73 | map_ = new AddressToRangeMap(); |
74 | |
75 | MapIterator iterator_base = map_->lower_bound(base); |
76 | MapIterator iterator_high = map_->lower_bound(high); |
77 | MapIterator iterator_end = map_->end(); |
78 | |
79 | if (iterator_base == iterator_high && iterator_base != iterator_end && |
80 | base >= iterator_base->second->base_) { |
81 | // The new range is entirely within an existing child range. |
82 | |
83 | // If the new range's geometry is exactly equal to an existing child |
84 | // range's, it violates the containment rules, and an attempt to store |
85 | // it must fail. iterator_base->first contains the key, which was the |
86 | // containing child's high address. |
87 | if (!allow_equal_range_ && iterator_base->second->base_ == base && |
88 | iterator_base->first == high) { |
89 | // TODO(nealsid): See the TODO above on why this is commented out. |
90 | // BPLOG(INFO) << "StoreRange failed, identical range is already " |
91 | // "present: " << HexString(base) << "+" << |
92 | // HexString(size); |
93 | return false; |
94 | } |
95 | |
96 | // Pass the new range on to the child to attempt to store. |
97 | return iterator_base->second->StoreRange(base, size, entry); |
98 | } |
99 | |
100 | // iterator_high might refer to an irrelevant range: one whose base address |
101 | // is higher than the new range's high address. Set contains_high to true |
102 | // only if iterator_high refers to a range that is at least partially |
103 | // within the new range. |
104 | bool contains_high = iterator_high != iterator_end && |
105 | high >= iterator_high->second->base_; |
106 | |
107 | // If the new range encompasses any existing child ranges, it must do so |
108 | // fully. Partial containment isn't allowed. |
109 | if ((iterator_base != iterator_end && base > iterator_base->second->base_) || |
110 | (contains_high && high < iterator_high->first)) { |
111 | // TODO(mmentovai): Some symbol files will trip this check frequently |
112 | // on STACK lines. Too many messages will be produced. These are more |
113 | // suitable for a DEBUG channel than an INFO channel. |
114 | // BPLOG(INFO) << "StoreRange failed, new range partially contains " |
115 | // "existing range: " << HexString(base) << "+" << |
116 | // HexString(size); |
117 | return false; |
118 | } |
119 | |
120 | // When copying and erasing contained ranges, the "end" iterator needs to |
121 | // point one past the last item of the range to copy. If contains_high is |
122 | // false, the iterator's already in the right place; the increment is safe |
123 | // because contains_high can't be true if iterator_high == iterator_end. |
124 | if (contains_high) |
125 | ++iterator_high; |
126 | |
127 | // Optimization: if the iterators are equal, no child ranges would be |
128 | // moved. Create the new child range with a NULL map to conserve space |
129 | // in leaf nodes, of which there will be many. |
130 | AddressToRangeMap* child_map = NULL; |
131 | |
132 | if (iterator_base != iterator_high) { |
133 | // The children of this range that are contained by the new range must |
134 | // be transferred over to the new range. Create the new child range map |
135 | // and copy the pointers to range maps it should contain into it. |
136 | child_map = new AddressToRangeMap(iterator_base, iterator_high); |
137 | |
138 | // Remove the copied child pointers from this range's map of children. |
139 | map_->erase(iterator_base, iterator_high); |
140 | } |
141 | |
142 | // Store the new range in the map by its high address. Any children that |
143 | // the new child range contains were formerly children of this range but |
144 | // are now this range's grandchildren. Ownership of these is transferred |
145 | // to the new child range. |
146 | ContainedRangeMap* new_child = |
147 | new ContainedRangeMap(base, entry, child_map, allow_equal_range_); |
148 | |
149 | map_->insert(MapValue(high, new_child)); |
150 | return true; |
151 | } |
152 | |
153 | |
154 | template<typename AddressType, typename EntryType> |
155 | bool ContainedRangeMap<AddressType, EntryType>::RetrieveRange( |
156 | const AddressType& address, EntryType* entry) const { |
157 | BPLOG_IF(ERROR, !entry) << "ContainedRangeMap::RetrieveRange requires " |
158 | "|entry|" ; |
159 | assert(entry); |
160 | |
161 | // If nothing was ever stored, then there's nothing to retrieve. |
162 | if (!map_) |
163 | return false; |
164 | |
165 | // Get an iterator to the child range whose high address is equal to or |
166 | // greater than the supplied address. If the supplied address is higher |
167 | // than all of the high addresses in the range, then this range does not |
168 | // contain a child at address, so return false. If the supplied address |
169 | // is lower than the base address of the child range, then it is not within |
170 | // the child range, so return false. |
171 | MapConstIterator iterator = map_->lower_bound(address); |
172 | if (iterator == map_->end() || address < iterator->second->base_) |
173 | return false; |
174 | |
175 | // The child in iterator->second contains the specified address. Find out |
176 | // if it has a more-specific descendant that also contains it. If it does, |
177 | // it will set |entry| appropriately. If not, set |entry| to the child. |
178 | if (!iterator->second->RetrieveRange(address, entry)) |
179 | *entry = iterator->second->entry_; |
180 | |
181 | return true; |
182 | } |
183 | |
184 | template <typename AddressType, typename EntryType> |
185 | bool ContainedRangeMap<AddressType, EntryType>::RetrieveRanges( |
186 | const AddressType& address, |
187 | std::vector<const EntryType*>& entries) const { |
188 | // If nothing was ever stored, then there's nothing to retrieve. |
189 | if (!map_) |
190 | return false; |
191 | MapIterator iterator = map_->lower_bound(address); |
192 | if (iterator == map_->end() || address < iterator->second->base_) |
193 | return false; |
194 | iterator->second->RetrieveRanges(address, entries); |
195 | entries.push_back(&iterator->second->entry_); |
196 | return true; |
197 | } |
198 | |
199 | template<typename AddressType, typename EntryType> |
200 | void ContainedRangeMap<AddressType, EntryType>::Clear() { |
201 | if (map_) { |
202 | MapConstIterator end = map_->end(); |
203 | for (MapConstIterator child = map_->begin(); child != end; ++child) |
204 | delete child->second; |
205 | |
206 | delete map_; |
207 | map_ = NULL; |
208 | } |
209 | } |
210 | |
211 | |
212 | } // namespace google_breakpad |
213 | |
214 | |
215 | #endif // PROCESSOR_CONTAINED_RANGE_MAP_INL_H__ |
216 | |