Patch re2 to support MSan.

third_party/re2/util/sparse_set.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
 // 
 // SparseSet<T>(m) is a set of integers in [0, m).
 // It requires sizeof(int)*m memory, but it provides
 // fast iteration through the elements in the set and fast clearing
 // of the set.
@@ skipping 36 matching lines @@
 #ifndef RE2_UTIL_SPARSE_SET_H__
 #define RE2_UTIL_SPARSE_SET_H__
 
 #include "util/util.h"
 
 namespace re2 {
 
 class SparseSet {
  public:
   SparseSet()
-    : size_(0), max_size_(0), sparse_to_dense_(NULL), dense_(NULL), valgrind_(RunningOnValgrind()) {}
+    : size_(0), max_size_(0), sparse_to_dense_(NULL), dense_(NULL),
+#if defined(MEMORY_SANITIZER)
+      valgrind_(true)
+#else
+      valgrind_(RunningOnValgrind())
+#endif
+  {
+  }
 
   SparseSet(int max_size) {
     max_size_ = max_size;
     sparse_to_dense_ = new int[max_size];
     dense_ = new int[max_size];
+#if defined(MEMORY_SANITIZER)
+    valgrind_ = true;
+#else
     valgrind_ = RunningOnValgrind();
+#endif
     // Don't need to zero the memory, but do so anyway
     // to appease Valgrind.
     if (valgrind_) {
       for (int i = 0; i < max_size; i++) {
         dense_[i] = 0xababababU;
         sparse_to_dense_[i] = 0xababababU;
       }
     }
     size_ = 0;
   }
@@ skipping 96 matching lines @@
   int* sparse_to_dense_;
   int* dense_;
   bool valgrind_;
 
   DISALLOW_EVIL_CONSTRUCTORS(SparseSet);
 };
 
 }  // namespace re2
 
 #endif  // RE2_UTIL_SPARSE_SET_H__