Add hash function for IntervalDomain

Summary: Move hash function for IntervalDomain from MT to sparta since it appears quite re-usable. Reviewed By: arnaudvenet Differential Revision: D48239105 fbshipit-source-id: 2bff16f61d839aa1fc4cf71b3574a8c3c95feb2e
facebook · Aug 11, 2023 · 980e2b2 · 980e2b2
1 parent 250e104
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diff --git a/sparta/include/sparta/IntervalDomain.h b/sparta/include/sparta/IntervalDomain.h
@@ -11,6 +11,8 @@
 #include <limits>
 #include <ostream>
 
+#include <boost/functional/hash.hpp>
+
 #include <sparta/AbstractDomain.h>
 
 namespace sparta {
@@ -264,3 +266,20 @@ inline std::ostream& operator<<(std::ostream& o,
 }
 
 } // namespace sparta
+
+template <typename Num>
+struct std::hash<sparta::IntervalDomain<Num>> {
+  std::size_t operator()(const sparta::IntervalDomain<Num>& interval) const {
+    std::size_t seed = 0;
+
+    if (interval.is_bottom()) {
+      boost::hash_combine(seed, sparta::IntervalDomain<Num>::MAX);
+      boost::hash_combine(seed, sparta::IntervalDomain<Num>::MIN);
+    } else {
+      boost::hash_combine(seed, interval.lower_bound());
+      boost::hash_combine(seed, interval.upper_bound());
+    }
+
+    return seed;
+  }
+};
diff --git a/sparta/test/IntervalDomainTest.cpp b/sparta/test/IntervalDomainTest.cpp
@@ -148,4 +148,23 @@ TEST(IntervalDomainTest, lattice) {
   EXPECT_EQ(top.narrowing(b).narrowing(a), Domain::finite(0, 4));
 }
 
+TEST(IntervalDomainTest, hash) {
+  const auto top = Domain::top();
+  const auto bot = Domain::bottom();
+
+  const auto a = Domain::finite(0, 5);
+
+  EXPECT_NE(std::hash<Domain>()(top), std::hash<Domain>()(bot));
+  EXPECT_NE(std::hash<Domain>()(top), std::hash<Domain>()(a));
+  EXPECT_EQ(std::hash<Domain>()(top), std::hash<Domain>()(top));
+
+  EXPECT_EQ(std::hash<Domain>()(bot), std::hash<Domain>()(bot));
+  EXPECT_NE(std::hash<Domain>()(bot), std::hash<Domain>()(a));
+  EXPECT_NE(std::hash<Domain>()(bot), std::hash<Domain>()(top));
+
+  EXPECT_NE(std::hash<Domain>()(a), std::hash<Domain>()(bot));
+  EXPECT_EQ(std::hash<Domain>()(a), std::hash<Domain>()(a));
+  EXPECT_NE(std::hash<Domain>()(a), std::hash<Domain>()(top));
+}
+
 } // namespace