1  // Copyright 2006 Google LLC
  2  //
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  4  // modification, are permitted provided that the following conditions are
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  9  //     * Redistributions in binary form must reproduce the above
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 11  // in the documentation and/or other materials provided with the
 12  // distribution.
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 14  // contributors may be used to endorse or promote products derived from
 15  // this software without specific prior written permission.
 16  //
 17  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 18  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 20  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 21  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 22  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 23  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 27  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 28  
 29  // contained_range_map-inl.h: Hierarchically-organized range map implementation.
 30  //
 31  // See contained_range_map.h for documentation.
 32  //
 33  // Author: Mark Mentovai
 34  
 35  #ifndef PROCESSOR_CONTAINED_RANGE_MAP_INL_H__
 36  #define PROCESSOR_CONTAINED_RANGE_MAP_INL_H__
 37  
 38  #include "processor/contained_range_map.h"
 39  
 40  #include <assert.h>
 41  
 42  #include "processor/logging.h"
 43  
 44  
 45  namespace google_breakpad {
 46  
 47  
 48  template<typename AddressType, typename EntryType>
 49  ContainedRangeMap<AddressType, EntryType>::~ContainedRangeMap() {
 50    // Clear frees the children pointed to by the map, and frees the map itself.
 51    Clear();
 52  }
 53  
 54  
 55  template<typename AddressType, typename EntryType>
 56  bool ContainedRangeMap<AddressType, EntryType>::StoreRange(
 57      const AddressType& base, const AddressType& size, const EntryType& entry) {
 58    AddressType high = base + size - 1;
 59  
 60    // Check for undersize or overflow.
 61    if (size <= 0 || high < base) {
 62      //TODO(nealsid) We are commenting this out in order to prevent
 63      // excessive logging.  We plan to move to better logging as this
 64      // failure happens quite often and is expected(see comment in
 65      // basic_source_line_resolver.cc:671).
 66      // BPLOG(INFO) << "StoreRange failed, " << HexString(base) << "+"
 67      // << HexString(size) << ", " << HexString(high);
 68      return false;
 69    }
 70  
 71    if (!map_)
 72      map_ = new AddressToRangeMap();
 73  
 74    MapIterator iterator_base = map_->lower_bound(base);
 75    MapIterator iterator_high = map_->lower_bound(high);
 76    MapIterator iterator_end = map_->end();
 77  
 78    if (iterator_base == iterator_high && iterator_base != iterator_end &&
 79        base >= iterator_base->second->base_) {
 80      // The new range is entirely within an existing child range.
 81  
 82      // If the new range's geometry is exactly equal to an existing child
 83      // range's, it violates the containment rules, and an attempt to store
 84      // it must fail.  iterator_base->first contains the key, which was the
 85      // containing child's high address.
 86      if (!allow_equal_range_ && iterator_base->second->base_ == base &&
 87          iterator_base->first == high) {
 88        // TODO(nealsid): See the TODO above on why this is commented out.
 89        //       BPLOG(INFO) << "StoreRange failed, identical range is already "
 90        //                      "present: " << HexString(base) << "+" <<
 91        //                      HexString(size);
 92        return false;
 93      }
 94  
 95      // Pass the new range on to the child to attempt to store.
 96      return iterator_base->second->StoreRange(base, size, entry);
 97    }
 98  
 99    // iterator_high might refer to an irrelevant range: one whose base address
100    // is higher than the new range's high address.  Set contains_high to true
101    // only if iterator_high refers to a range that is at least partially
102    // within the new range.
103    bool contains_high = iterator_high != iterator_end &&
104                         high >= iterator_high->second->base_;
105  
106    // If the new range encompasses any existing child ranges, it must do so
107    // fully.  Partial containment isn't allowed.
108    if ((iterator_base != iterator_end && base > iterator_base->second->base_) ||
109        (contains_high && high < iterator_high->first)) {
110      // TODO(mmentovai): Some symbol files will trip this check frequently
111      // on STACK lines.  Too many messages will be produced.  These are more
112      // suitable for a DEBUG channel than an INFO channel.
113      // BPLOG(INFO) << "StoreRange failed, new range partially contains "
114      //               "existing range: " << HexString(base) << "+" <<
115      //               HexString(size);
116      return false;
117    }
118  
119    // When copying and erasing contained ranges, the "end" iterator needs to
120    // point one past the last item of the range to copy.  If contains_high is
121    // false, the iterator's already in the right place; the increment is safe
122    // because contains_high can't be true if iterator_high == iterator_end.
123    if (contains_high)
124      ++iterator_high;
125  
126    // Optimization: if the iterators are equal, no child ranges would be
127    // moved.  Create the new child range with a NULL map to conserve space
128    // in leaf nodes, of which there will be many.
129    AddressToRangeMap* child_map = NULL;
130  
131    if (iterator_base != iterator_high) {
132      // The children of this range that are contained by the new range must
133      // be transferred over to the new range.  Create the new child range map
134      // and copy the pointers to range maps it should contain into it.
135      child_map = new AddressToRangeMap(iterator_base, iterator_high);
136  
137      // Remove the copied child pointers from this range's map of children.
138      map_->erase(iterator_base, iterator_high);
139    }
140  
141    // Store the new range in the map by its high address.  Any children that
142    // the new child range contains were formerly children of this range but
143    // are now this range's grandchildren.  Ownership of these is transferred
144    // to the new child range.
145    ContainedRangeMap* new_child =
146        new ContainedRangeMap(base, entry, child_map, allow_equal_range_);
147  
148    map_->insert(MapValue(high, new_child));
149    return true;
150  }
151  
152  
153  template<typename AddressType, typename EntryType>
154  bool ContainedRangeMap<AddressType, EntryType>::RetrieveRange(
155      const AddressType& address, EntryType* entry) const {
156    BPLOG_IF(ERROR, !entry) << "ContainedRangeMap::RetrieveRange requires "
157                               "|entry|";
158    assert(entry);
159  
160    // If nothing was ever stored, then there's nothing to retrieve.
161    if (!map_)
162      return false;
163  
164    // Get an iterator to the child range whose high address is equal to or
165    // greater than the supplied address.  If the supplied address is higher
166    // than all of the high addresses in the range, then this range does not
167    // contain a child at address, so return false.  If the supplied address
168    // is lower than the base address of the child range, then it is not within
169    // the child range, so return false.
170    MapConstIterator iterator = map_->lower_bound(address);
171    if (iterator == map_->end() || address < iterator->second->base_)
172      return false;
173  
174    // The child in iterator->second contains the specified address.  Find out
175    // if it has a more-specific descendant that also contains it.  If it does,
176    // it will set |entry| appropriately.  If not, set |entry| to the child.
177    if (!iterator->second->RetrieveRange(address, entry))
178      *entry = iterator->second->entry_;
179  
180    return true;
181  }
182  
183  template <typename AddressType, typename EntryType>
184  bool ContainedRangeMap<AddressType, EntryType>::RetrieveRanges(
185      const AddressType& address,
186      std::vector<const EntryType*>& entries) const {
187    // If nothing was ever stored, then there's nothing to retrieve.
188    if (!map_)
189      return false;
190    MapIterator iterator = map_->lower_bound(address);
191    if (iterator == map_->end() || address < iterator->second->base_)
192      return false;
193    iterator->second->RetrieveRanges(address, entries);
194    entries.push_back(&iterator->second->entry_);
195    return true;
196  }
197  
198  template<typename AddressType, typename EntryType>
199  void ContainedRangeMap<AddressType, EntryType>::Clear() {
200    if (map_) {
201      MapConstIterator end = map_->end();
202      for (MapConstIterator child = map_->begin(); child != end; ++child)
203        delete child->second;
204  
205      delete map_;
206      map_ = NULL;
207    }
208  }
209  
210  
211  }  // namespace google_breakpad
212  
213  
214  #endif  // PROCESSOR_CONTAINED_RANGE_MAP_INL_H__