Memoize loc_t hashes

p4lang · Jul 17, 2024 · 148e2d4 · 148e2d4
1 parent 18c06c9
commit 148e2d4
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Showing 2 changed files with 8 additions and 3 deletions.
diff --git a/frontends/p4/def_use.cpp b/frontends/p4/def_use.cpp
@@ -764,9 +764,13 @@ void ComputeWriteSet::visitVirtualMethods(const IR::IndexedVector<IR::Declaratio
 }
 
 std::size_t P4::loc_t::hash() const {
-    if (!parent) return Util::Hash{}(node->id);
-
-    return Util::Hash{}(node->id, parent->hash());
+    if (!computedHash) {
+        if (!parent)
+            computedHash = Util::Hash{}(node->id);
+        else
+            computedHash = Util::Hash{}(node->id, parent->hash());
+    }
+    return computedHash;
 }
 
 // Returns program location of n, given the program location of n's direct parent.

diff --git a/frontends/p4/def_use.h b/frontends/p4/def_use.h
@@ -39,6 +39,7 @@ class LocationSet;
 struct loc_t {
     const IR::Node *node;
     const loc_t *parent;
+    mutable std::size_t computedHash = 0;
     bool operator==(const loc_t &a) const {
         if (node != a.node) return false;
         if (parent == a.parent) return true;