Support unique constraints (on 1D static arrays) (#6810) (#6878)

include/verilated_random.cpp

@@ -367,7 +367,26 @@ void VlRandomizer::randomConstraint(std::ostream& os, VlRNG& rngr, int bits) {
 }
 
 bool VlRandomizer::next(VlRNG& rngr) {
-    if (m_vars.empty()) return true;
+    if (m_vars.empty() && m_unique_arrays.empty()) return true;
+    for (const std::string& baseName : m_unique_arrays) {
+        const auto it = m_vars.find(baseName);
+
+        // Look up the actual size we stored earlier
+        // const uint32_t size = m_unique_array_sizes[baseName];
+        const uint32_t size = m_unique_array_sizes.at(baseName);
+
+        if (it != m_vars.end()) {
+            std::string distinctExpr = "(__Vbv (distinct";
+            for (uint32_t i = 0; i < size; ++i) {
+                char hexIdx[12];
+                sprintf(hexIdx, "#x%08x", i);
+                distinctExpr += " (select " + it->first + " " + hexIdx + ")";
+            }
+            distinctExpr += "))";
+            m_constraints.push_back(distinctExpr);
+        }
+    }
+
     std::iostream& os = getSolver();
     if (!os) return false;
 
@@ -384,6 +403,7 @@ bool VlRandomizer::next(VlRNG& rngr) {
         var.second->emitType(os);
         os << ")\n";
     }
+
     for (const std::string& constraint : m_constraints) {
         os << "(assert (= #b1 " << constraint << "))\n";
     }