Fix randomization of dynamic arrs of objects

Signed-off-by: Ryszard Rozak <rrozak@antmicro.com>

src/V3Randomize.cpp

@@ -4569,6 +4569,16 @@ class RandomizeVisitor final : public VNVisitor {
         }
     }
 
+    static bool isDynArrOfClassTypeRecurse(const AstNodeDType* const dtypep) {
+        const AstNodeDType* const refp = dtypep->skipRefp();
+        if (VN_IS(refp, DynArrayDType) || VN_IS(refp, QueueDType)) {
+            return isDynArrOfClassTypeRecurse(refp->subDTypep());
+        } else if (VN_IS(refp, ClassRefDType)) {
+            return true;
+        }
+        return false;
+    }
+
     // VISITORS
     void visit(AstNodeModule* nodep) override {
         VL_RESTORER(m_modp);
@@ -4801,6 +4811,18 @@ class RandomizeVisitor final : public VNVisitor {
 
                 // Refresh array element tables after resize
                 for (AstVar* const arrVarp : sizeArraysIt->second) {
+                    // Array elements of class data type are passed to the solver as separate
+                    // variables, so passing the original array variable is redundant, because it
+                    // won't be referenced
+                    if (isDynArrOfClassTypeRecurse(arrVarp->dtypep())) {
+                        const uint32_t unpackedDims = arrVarp->dtypep()->dimensions(false).second;
+                        if (unpackedDims > 1) {
+                            arrVarp->v3warn(
+                                E_UNSUPPORTED,
+                                "Unsupported: Nested array element access in global constraint");
+                        }
+                        continue;
+                    }
                     AstCMethodHard* const methodp = new AstCMethodHard{
                         fl, new AstVarRef{fl, genModp, genp, VAccess::READWRITE},
                         VCMethod::RANDOMIZER_WRITE_VAR};

test_regress/t/t_constraint_global_cls_arr.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of either the GNU Lesser General Public License Version 3
+# or the Perl Artistic License Version 2.0.
+# SPDX-FileCopyrightText: 2025 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+
+if not test.have_solver:
+    test.skip("No constraint solver installed")
+
+test.compile()
+
+test.execute()
+
+test.passes()

test_regress/t/t_constraint_global_cls_arr.v

@@ -0,0 +1,37 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain.
+// SPDX-FileCopyrightText: 2026 Antmicro
+// SPDX-License-Identifier: CC0-1.0
+
+class Foo;
+  rand int abcd;
+endclass
+
+class Bar;
+  rand Foo foo_arr[];
+
+  function new();
+    foo_arr = new[12];
+    foreach(foo_arr[i]) foo_arr[i] = new;
+  endfunction
+
+  constraint c {
+    foo_arr.size() == 10;
+    foreach (foo_arr[i]) foo_arr[i].abcd < 8;
+  }
+endclass
+
+module t;
+  Bar bar;
+  initial begin
+    bar = new();
+    bar.randomize();
+    if (bar.foo_arr.size() != 10) $stop;
+    foreach (bar.foo_arr[i]) begin
+      if (bar.foo_arr[i] >= 8) $stop;
+    end
+    $write("*-* All Finished *-*\n");
+    $finish;
+  end
+endmodule

test_regress/t/t_constraint_global_cls_arr_2d_unsup.out

@@ -0,0 +1,6 @@
+%Error-UNSUPPORTED: t/t_constraint_global_cls_arr_2d_unsup.v:13:12: Unsupported: Nested array element access in global constraint
+                                                                  : ... note: In instance 't'
+   13 |   rand Foo foo_arr[$][];
+      |            ^~~~~~~
+                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
+%Error: Exiting due to

test_regress/t/t_constraint_global_cls_arr_2d_unsup.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of either the GNU Lesser General Public License Version 3
+# or the Perl Artistic License Version 2.0.
+# SPDX-FileCopyrightText: 2025 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('vlt')
+
+test.lint(fails=test.vlt_all, expect_filename=test.golden_filename)
+
+test.passes()

test_regress/t/t_constraint_global_cls_arr_2d_unsup.v

@@ -0,0 +1,41 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain.
+// SPDX-FileCopyrightText: 2026 Antmicro
+// SPDX-License-Identifier: CC0-1.0
+
+class Foo;
+  rand int abcd;
+   constraint c { abcd >= 2; }
+endclass
+
+class Bar;
+  rand Foo foo_arr[$][];
+
+  function new();
+    for (int i = 0; i < 3; i++) foo_arr[i] = new[5];
+    foreach(foo_arr[i, j]) foo_arr[i][j] = new;
+  endfunction
+
+  constraint c {
+    foo_arr.size() == 10;
+    foreach (foo_arr[i, j]) foo_arr[i][j].abcd < 8;
+  }
+endclass
+
+module t;
+  Bar bar;
+  initial begin
+    bar = new();
+    void'(bar.randomize());
+    if (bar.foo_arr.size() != 10) $stop;
+    foreach (bar.foo_arr[i, j]) begin
+      if (bar.foo_arr[i][j].abcd < 2 || bar.foo_arr[i][j].abcd >= 8) $stop;
+    end
+    for (int i = 3; i < 10; i++) begin
+      if (bar.foo_arr[i].size() != 0) $stop;
+    end
+    $write("*-* All Finished *-*\n");
+    $finish;
+  end
+endmodule