re2: Initialize sparse_to_dense_ on initial allocation under Valgrind.

third_party/re2/util/sparse_array.h

 // Copyright 2006 The RE2 Authors.  All Rights Reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // DESCRIPTION
 // 
 // SparseArray<T>(m) is a map from integers in [0, m) to T values.
 // It requires (sizeof(T)+sizeof(int))*m memory, but it provides
 // fast iteration through the elements in the array and fast clearing
 // of the array.  The array has a concept of certain elements being
@@ skipping 255 matching lines @@
 
 // Change the maximum size of the array.
 // Invalidates all iterators.
 template<typename Value>
 void SparseArray<Value>::resize(int new_max_size) {
   DebugCheckInvariants();
   if (new_max_size > max_size_) {
     int* a = new int[new_max_size];
     if (sparse_to_dense_) {
       memmove(a, sparse_to_dense_, max_size_*sizeof a[0]);
-      // Don't need to zero the memory but appease Valgrind.
-      if (valgrind_) {
-        for (int i = max_size_; i < new_max_size; i++)
-          a[i] = 0xababababU;
-      }
       delete[] sparse_to_dense_;
     }
+    // Don't need to zero the memory but appease Valgrind.
+    if (valgrind_) {
+      for (int i = max_size_; i < new_max_size; i++)
+        a[i] = 0xababababU;
+    }
     sparse_to_dense_ = a;
 
     dense_.resize(new_max_size);
   }
   max_size_ = new_max_size;
   if (size_ > max_size_)
     size_ = max_size_;
   DebugCheckInvariants();
 }
 
@@ skipping 152 matching lines @@
 
 // Comparison function for sorting.
 template<typename Value> bool SparseArray<Value>::less(const IndexValue& a,
                                                        const IndexValue& b) {
   return a.index_ < b.index_;
 }
 
 }  // namespace re2
 
 #endif  // RE2_UTIL_SPARSE_ARRAY_H__