hashlib: allow forcing Hasher state, use it for IdString trivial hashing

YosysHQ · Oct 30, 2024 · df44003 · df44003
1 parent 88f0774
commit df44003
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Showing 2 changed files with 13 additions and 0 deletions.
diff --git a/kernel/hashlib.h b/kernel/hashlib.h
@@ -132,6 +132,13 @@ class Hasher {
 		state ^= t;
 	}
 
+	void force(hash_t new_state) {
+		state = new_state;
+	}
+
+	bool is_new() const {
+		return state == Hasher().state;
+	}
 };
 
 template<typename T>

diff --git a/kernel/rtlil.h b/kernel/rtlil.h
@@ -361,6 +361,12 @@ namespace RTLIL
 		}
 
 		Hasher hash_acc(Hasher h) const {
+			// If we're starting a hashing sequence, simply start with unhashed ID
+			if (h.is_new()) {
+				h.force((Hasher::hash_t) index_);
+				return h;
+			}
+
 			return hash_ops<int>::hash_acc(index_, h);
 		}